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Find video protocols related to scientific articles indexed in Pubmed.
Post-synthesis DNA modifications using a trans-cyclooctene click handle.
Org. Biomol. Chem.
PUBLISHED: 11-20-2014
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Post-synthesis DNA modification is a very useful method for DNA functionalization. This is achieved by using a modified NTP, which has a handle for further modifications, replacing the corresponding natural NTP in polymerase-catalyzed DNA synthesis. Subsequently, the handle can be used for further functionalization after PCR, preferably through a very fast reaction. Herein we describe polymerase-mediated incorporation of trans-cyclooctene modified thymidine triphosphate (TCO-TTP). Subsequently, the trans-cyclooctene group was reacted with a tetrazine tethered to other functional groups through a very fast click reaction. The utility of this DNA functionalization method was demonstrated with the incorporation of a boronic acid group and a fluorophore. The same approach was also successfully used in modifying a known aptamer for fluorescent labelling applications.
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A click-and-release approach to CO prodrugs.
Chem. Commun. (Camb.)
PUBLISHED: 11-07-2014
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Carbon monoxide belongs to the family of signaling molecules and has been shown to possess therapeutic effects. Similar to NO, safe delivery of CO is a key issue in developing CO-based therapeutics. Herein we report a "click and release" CO-prodrug approach, which allows the release of CO under physiological conditions without the need for light irradiation. The system releases CO in a triggered and controllable manner and possesses the potential of tunable release rates.
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The high heritability of educational achievement reflects many genetically influenced traits, not just intelligence.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 10-06-2014
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Because educational achievement at the end of compulsory schooling represents a major tipping point in life, understanding its causes and correlates is important for individual children, their families, and society. Here we identify the general ingredients of educational achievement using a multivariate design that goes beyond intelligence to consider a wide range of predictors, such as self-efficacy, personality, and behavior problems, to assess their independent and joint contributions to educational achievement. We use a genetically sensitive design to address the question of why educational achievement is so highly heritable. We focus on the results of a United Kingdom-wide examination, the General Certificate of Secondary Education (GCSE), which is administered at the end of compulsory education at age 16. GCSE scores were obtained for 13,306 twins at age 16, whom we also assessed contemporaneously on 83 scales that were condensed to nine broad psychological domains, including intelligence, self-efficacy, personality, well-being, and behavior problems. The mean of GCSE core subjects (English, mathematics, science) is more heritable (62%) than the nine predictor domains (35-58%). Each of the domains correlates significantly with GCSE results, and these correlations are largely mediated genetically. The main finding is that, although intelligence accounts for more of the heritability of GCSE than any other single domain, the other domains collectively account for about as much GCSE heritability as intelligence. Together with intelligence, these domains account for 75% of the heritability of GCSE. We conclude that the high heritability of educational achievement reflects many genetically influenced traits, not just intelligence.
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Vitelline membrane outer layer 1 homolog interacts with lysozyme C and promotes the stabilization of tear film.
Invest. Ophthalmol. Vis. Sci.
PUBLISHED: 09-27-2014
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The aim of this study was to explore the possible interactions between vitelline membrane outer layer 1 homolog (VMO1) and other tear proteins and to determine the function of VMO1 in tear fluid.
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A Convenient Fluorescent Method to Simultaneously Determine the Enantiomeric Composition and Concentration of Functional Chiral Amines.
Chemistry
PUBLISHED: 09-04-2014
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A 1,1'-bi-2-naphthol (BINOL)-based chiral aldehyde in combination with Zn(II) shows a highly enantioselective fluorescent response toward functional chiral amines at ?>500?nm. However, the combination of salicylaldehyde and Zn(II) gives the same fluorescent enhancement for both enantiomers of a functional chiral amine at ?=447?nm. By using the fluorescent responses of the combination of the BINOL-based chiral aldehyde, salicylaldehyde and Zn(II) at the two emission wavelengths, both the concentration and enantiomeric composition of functional chiral amines such as amino alcohols, diamines, and amino acids can be simultaneously determined by a single fluorescent measurement. This work provides a simple and convenient method for chiral assay.
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Trap-state-dominated suppression of electron conduction in carbon nanotube thin-film transistors.
ACS Nano
PUBLISHED: 09-03-2014
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The often observed p-type conduction of single carbon nanotube field-effect transistors is usually attributed to the Schottky barriers at the metal contacts induced by the work function differences or by the doping effect of the oxygen adsorption when carbon nanotubes are exposed to air, which cause the asymmetry between electron and hole injections. However, for carbon nanotube thin-film transistors, our contrast experiments between oxygen doping and electrostatic doping demonstrate that the doping-generated transport barriers do not introduce any observable suppression of electron conduction, which is further evidenced by the perfect linear behavior of transfer characteristics with the channel length scaling. On the basis of the above observation, we conclude that the environmental adsorbates work by more than simply shifting the Fermi level of the CNTs; more importantly, these adsorbates cause a poor gate modulation efficiency of electron conduction due to the relatively large trap state density near the conduction band edge of the carbon nanotubes, for which we further propose quantitatively that the adsorbed oxygen-water redox couple is responsible.
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Reflexive anaphor resolution in spoken language comprehension: structural constraints and beyond.
Front Psychol
PUBLISHED: 08-19-2014
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We report results from an eye-tracking during listening study examining English-speaking adults' online processing of reflexive pronouns, and specifically whether the search for an antecedent is restricted to syntactically appropriate positions. Participants listened to a short story where the recipient of an object was introduced with a reflexive, and were asked to identify the object recipient as quickly as possible. This allowed for the recording of participants' o?ine interpretation of the reflexive, response times, and eye movements on hearing the reflexive. Whilst our o?ine results show that the ultimate interpretation for reflexives was constrained by binding principles, the response time, and eye-movement data revealed that during processing participants were temporarily distracted by a structurally inappropriate competitor antecedent when this was prominent in the discourse. These results indicate that in addition to binding principles, online referential decisions are also affected by discourse-level information.
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Precise determination of the threshold diameter for a single-walled carbon nanotube to collapse.
ACS Nano
PUBLISHED: 08-19-2014
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Closed-edged bilayer graphene nanoribbons were formed by the spontaneous collapse of large-diameter single-walled carbon nanotubes (SWNTs) grown on gold nanoparticles by chemical vapor deposition. Such bilayer graphene nanoribbons could adopt different stacking configurations, such as AB-stacking or stacking order with any rotation angle, correlated with the chiral angles of their parent rounded SWNTs. On the basis of the electron diffraction characterizations on a good number of collapsed and uncollapsed SWNTs, the threshold diameter for SWNTs to collapse was precisely determined to be 5.1 nm, independent of the chiral angle of the SWNTs. The determination is consistent with that calculated by both classical adaptive intermolecular reactive empirical bond order force field and density functional theory after having taken the stacking effect and thermal fluctuation into account.
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The role of lipid-based nano delivery systems on oral bioavailability enhancement of fenofibrate, a BCS II drug: comparison with fast-release formulations.
J Nanobiotechnology
PUBLISHED: 08-13-2014
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The aim of this study was to compare various formulations solid dispersion pellets (SDP), nanostructured lipid carriers (NLCs) and a self-microemulsifying drug delivery system (SMEDDS) generally accepted to be the most efficient drug delivery systems for BCS II drugs using fenofibrate (FNB) as a model drug. The size and morphology of NLCs and SMEDDS was characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Their release behaviors were investigated in medium with or without pancreatic lipase. The oral bioavailability of the various formulations was compared in beagle dogs using commercial Lipanthyl® capsules (micronized formulation) as a reference. The release of FNB from SDP was much faster than that from NLCs and SMEDDS in medium without lipase, whereas the release rate from NLCs and SMEDDS was increased after adding pancreatic lipase into the release medium. However, NLCs and SMEDDS increased the bioavailability of FNB to 705.11% and 809.10%, respectively, in comparison with Lipanthyl® capsules, although the relative bioavailability of FNB was only 366.05% after administration of SDPs. Thus, lipid-based drug delivery systems (such as NLCs and SMEDDS) may have more advantages than immediate release systems (such as SDPs and Lipanthyl® capsules).
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Nickel-catalyzed decarboxylative C-P cross-coupling of alkenyl acids with P(O)H compounds.
J. Org. Chem.
PUBLISHED: 08-08-2014
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The first nickel-catalyzed decarboxylative C-P coupling of a wide range of alkenyl acids with various P(O)H compounds, especially for H-phosphonates, has been developed, affording a versatile and efficient tool for the preparation of valuable (E)-1-alkenylphosphonates, (E)-1-alkenylphosphinate oxides, and (E)-1-alkenylphosphine oxides with high stereoselectivity and broad substrate applicability. DFT calculation revealed that the phosphine ligand exhibits better catalytic performance than the nitrogen ligand in the reductive elimination step owing to the stronger nucleophilicity and larger size.
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Cloning and Sequence Analysis of Wild Argali ISG15 cDNA.
Asian-australas. J. Anim. Sci.
PUBLISHED: 07-23-2014
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The complete coding sequence of Wild Argali ISG15 cDNA was generated by rapid amplification of cDNA ends. The ISG15 cDNA was 642 bp with an open reading frame of 474 bp, which encoded a 17.47 kDa protein composed of 157 amino acids. Its amino acid sequence shared 97.9%, 80.8%, 91.4%, 94.3%, 78.3% identity with those of ISG15cDNA from Ovis aries (accession no. NM001009735.1), Capra hircus (accession no. HQ329186.1), Bos taurus (accession no. BC102318.1), Bubalus bubalis (accession no. HM543269.1), and Sus scrofa (accession no. EU647216.1), respectively. The entire coding sequence was inserted into the pET-28a vector and expressed in E. coli. The recombinant protein corresponded to the expected molecular mass of 25 kDa as judged by SDS-PAGE, and it was detected in the bacterial inclusion bodies. The expressed protein could be purified by Ni(2+) chelate affinity chromatography and the results from the lymphocyte proliferation test showed that the product could stimulate lymphocyte proliferation very well (p<0.05), which further confirmed its biological activity.
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A study into the extracted ion number for NASICON structured Na?V?(PO?)? in sodium-ion batteries.
Phys Chem Chem Phys
PUBLISHED: 07-17-2014
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Excellent C-rate and cycling performance with a high specific capacity of 117.6 mA h g(-1) have been achieved on NASICON-structure Na3V2(PO4)3 sodium-ion batteries. Two different Na sites, namely Na(1) and Na(2), are reported in the open three-dimensional framework, of which the ions at the Na(2) sites should be mainly responsible for the electrochemical properties. It is vitally important and interesting to find that there are two kinds of possible ion occupation of Na ions in Na3V2(PO4)3 and the investigation of ion-extraction number is firstly explored by discussing ion occupations with the help of first-principles calculations. The ion occupation of 0.75 for all Na sites is suitable for the configuration of [Na3V2(PO4)3]2, and the two-step extraction process accompanied by structure reorganization can account for the theoretical capacity of Na3V2(PO4)3.
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New insight in understanding oxygen reduction and evolution in solid-state lithium-oxygen batteries using an in situ environmental scanning electron microscope.
Nano Lett.
PUBLISHED: 07-07-2014
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Via designing a facile microscale all-solid-state lithium-oxygen battery system constructed in an environmental scanning electron microscope, direct visualization of discharge and charge processes of the lithium-oxygen battery is achieved. Different morphologies of the discharge product are observed, including a sphere, conformal film, and red-blood-cell-like shape, with a particle size up to 1.5 ?m; whereas upon charge, the decomposition initiates at their surface and continues along a certain direction, instead of from the contact point at the electrode. These new findings indicate that the electron and lithium ion conductivities of Li2O2 could support the growth and decomposition of the discharge product in our system. In addition, our results indicate that various morphologies of Li2O2 arise from the different current density and surface chemistry of CNT, and the growth and decomposition of the particle are related to the uneven distribution of the ionic and electronic conductivities of Li2O2.
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Preparation of multi-functional cellulose containing huge conjugated system and its UV-protective and antibacterial property.
Carbohydr Polym
PUBLISHED: 06-28-2014
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A novel Schiff base containing huge azo conjugated system and reactive groups, 3,5-bis{2-hydroxyphenyl-5-[(2-sulfate-4-sulfatoethylsulfonyl-azobenzol)methylene amino]}benzoic acid (BHSABA) was applied to modify cellulose. Exhaustion and grafting reactive rate, and grafting quantity of BHSABA on cellulose were calculated. The chemical structure of the modified cellulose was characterized and thermal degradation and morphology were also investigated. The UV protection and antibacterial properties were measured. With increasing the concentration of BHSABA, grafting quantity of BHSABA on cellulose increased from 1.52 × 10(-2)mmol/g to 5.08 × 10(-2)mmol/g. The multi-functional cellulose fabrics had excellent UV-protective property, which possessed very high UPF value and very low ultraviolet transmittance. The UPF values exceeded 50 and the ultraviolet transmittances were all less than 1%. They also exhibited moderate activity against Staphylococcus aureus and after 10 times washing still maintained antibacterial activity. The onsets of degradation slightly decreased. With increasing the grafting quantity of BHSABA on cellulose, mass loss yields of the residues increased. The morphological structure had no noticeable change.
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Sputtering graphite coating to improve the elevated-temperature cycling ability of the LiMn2O4 electrode.
Phys Chem Chem Phys
PUBLISHED: 06-26-2014
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To improve the cycle performance of LiMn2O4 at elevated temperature, a graphite layer is introduced to directly cover the surface of a commercial LiMn2O4-based electrode via room-temperature DC magnetron sputtering. The as-modified cathodes display improved capacity retention as compared to the bare LiMn2O4 cathode (BLMO) at 55 °C. When sputtering graphite for 30 min, the sample shows the best cycling performance at 55 °C, maintaining 96.2% capacity retention after 200 cycles. Reasons with respect to the graphite layer for improving the elevated-temperature performance of LiMn2O4 are systematically investigated via the methods of cyclic voltammetry, electrochemical impedance spectroscopy, X-ray photoelectron spectrometry, scanning and transmission electron microscopy, X-ray diffraction and inductively coupled plasma-atomic emission spectrometry. The results demonstrate that the graphite coated LiMn2O4 cathode has much less increased electrode polarization and electrochemical impedance than BLMO during the elevated-temperature cycling process. Furthermore, the graphite layer is able to alleviate the severe dissolution of manganese ions into the electrolyte and mitigate the morphological and structural degradation of LiMn2O4 during cycling. A model for the electrochemical kinetics process is also suggested for explaining the roles of the graphite layer in suppressing the Mn dissolution.
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Highly exothermic and superhydrophobic Mg/fluorocarbon core/shell nanoenergetic arrays.
ACS Appl Mater Interfaces
PUBLISHED: 06-23-2014
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Mg/fluorocarbon core/shell nanoenergetic arrays are prepared onto silicon substrate, with Mg nanorods as the core and fluorocarbon as the shell. Mg nanorods are deposited by the glancing angle deposition technique, and the fluorocarbon layer is then prepared as a shell to encase the Mg nanorods by the magnetron sputtering deposition process. Scanning electron microscopy and transmission electron microscopy show the core/shell structure of the Mg/fluorocarbon arrays. X-ray energy-dispersive spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy are used to characterize the structural composition of the Mg/fluorocarbon. It is found that the as-prepared fluorocarbon layer consists of shorter molecular chains compared to that of bulk polytetrafluoroethylene, which is proven beneficial to the low onset reaction temperature of Mg/fluorocarbon. Water contact angle test demonstrates the superhydrophobicity of the Mg/fluorocarbon arrays, and a static contact angle as high as 162° is achieved. Thermal analysis shows that the Mg/fluorocarbon material exhibits a very low onset reaction temperature of about 270 °C as well as an ultrahigh heat of reaction approaching 9 kJ/g. A preliminary combustion test reveals rapid combustion wave propagation, and a convective mechanism is adopted to explain the combustion behaviors.
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Fasudil inhibits prostate cancer-induced angiogenesis in vitro.
Oncol. Rep.
PUBLISHED: 06-16-2014
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Inhibition of angiogenesis is an important therapeutic strategy for advanced stage prostate cancer (PCa). RhoA/Rho-associated protein kinases (ROCK) are key regulators of the cytoskeleton and have been implicated in PCa angiogenesis. We investigated the anti-angiogenic effects of fasudil, a ROCK inhibitor, on PCa-induced angiogenesis in vitro. Proliferation of PCa-conditioned human umbilical vein endothelial cells (HUVECs) was assessed using a bromodeoxyuridine (BrdU) assay, and migration was assessed with a wound healing assay. In vitro angiogenesis of PCa-conditioned HUVECs was evaluated by tube formation and a spheroid sprouting assay. Fasudil inhibited PCa-induced endothelial cell proliferation at a concentration of 100 µM, and also decreased PCa-induced endothelial cell migration at a concentration of 30 µM. In the in vitro angiogenesis assay, fasudil exerted a more significant effect. Tube formation was significantly inhibited at fasudil concentrations exceeding 3 µM, and spheroid sprouts were significantly thinner and shorter (at fasudil concentrations of 10 and 30 µM, respectively). Western blotting results showed that expression of phosphorylated myosin phosphatase target subunit 1 (MYPT-1) was significantly lower after fasudil treatment, confirming that fasudil inhibited ROCK activity in these model systems. These data suggest that fasudil may be a useful anti-angiogenic agent for PCa.
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Effect of nano-structured bioceramic surface on osteogenic differentiation of adipose derived stem cells.
Biomaterials
PUBLISHED: 06-07-2014
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Tissue engineering strategies to construct vascularized bone grafts potentially revolutionize the treatment of massive bone loss. The surface topography of the grafts plays critical roles on bone regeneration, while adipose derived stem cells (ASCs) are known for their capability to promote osteogenesis and angiogenesis when applied to bone defects. In the present study, the effects of hydroxyapatite (HAp) bioceramic scaffolds with nanosheet, nanorod, and micro-nano-hybrid (the hybrid of nanorod and microrod) surface topographies on attachment, proliferation and osteogenic differentiation, as well as the expression of angiogenic factors of rat ASCs were systematically investigated. The results showed that the HAp bioceramic scaffolds with the micro-/nano-topography surfaces significantly enhanced cell attachment and viability, alkaline phosphatase (ALP) activity, and mRNA expression levels of osteogenic markers and angiogenic factors of ASCs. More importantly, the biomimetic feature of the hierarchical micro-nano-hybrid surface topography showed the highest stimulatory effect. The activation in Akt signaling pathway was observed in ASCs cultured on HAp bioceramics with nanorod, and micro-nano-hybrid surface topographies. Moreover, these induction effects could be repressed by Akt signaling pathway inhibitor LY294002. Finally, the in vivo bone regeneration results of rat critical-sized calvarial defect models confirmed that the combination of the micro-nano-hybrid surface and ASCs could significantly enhance both osteogenesis and angiogenesis as compared with the control HAp bioceramic scaffold with traditional smooth surface. Our results suggest that HAp bioceramic scaffolds with micro-nano-hybrid surface can act as cell carrier for ASCs, and consequently combine with ASCs to construct vascularized tissue-engineered bone.
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Sulfur nanocrystals confined in carbon nanotube network as a binder-free electrode for high-performance lithium sulfur batteries.
Nano Lett.
PUBLISHED: 06-06-2014
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A binder-free nano sulfur-carbon nanotube composite material featured by clusters of sulfur nanocrystals anchored across the superaligned carbon nanotube (SACNT) matrix is fabricated via a facile solution-based method. The conductive SACNT matrix not only avoids self-aggregation and ensures dispersive distribution of the sulfur nanocrystals but also offers three-dimensional continuous electron pathway, provides sufficient porosity in the matrix to benefit electrolyte infiltration, confines the sulfur/polysulfides, and accommodates the volume variations of sulfur during cycling. The nanosized sulfur particles shorten lithium ion diffusion path, and the confinement of sulfur particles in the SACNT network guarantees the stability of structure and electrochemical performance of the composite. The nano S-SACNT composite cathode delivers an initial discharge capacity of 1071 mAh g(-1), a peak capacity of 1088 mAh g(-1), and capacity retention of 85% after 100 cycles with high Coulombic efficiency (?100%) at 1 C. Moreover, at high current rates the nano S-SACNT composite displays impressive capacities of 1006 mAh g(-1) at 2 C, 960 mAh g(-1) at 5 C, and 879 mAh g(-1) at 10 C.
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Can surface EMG be adequately described by digital sampling?
Nonlinear Dynamics Psychol Life Sci
PUBLISHED: 06-05-2014
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Surface electromyography (SEMG) is a common tool to evaluate muscle function in kinesiological studies, musculoskeletal rehabilitation, prosthetics, clinical research and neurological disease diagnosis. The acquisition of SEMG is a crucially basic issue to gain an insight into musculoskeletal system function. The aim of this study is to investigate if the sampled surface EMG signals can reflect adequately the neural activity of the underlying musculature. The surface EMG signals of four muscles (abductor pollicis muscles and abductor digiti minimi muscles of right hand and left hand) are studied on the amplitude, frequency and nonlinear measure based on symplectic geometry. There are obvious differences in nonlinear measures of the different sampled signals, although there are little significant changes in their amplitude and frequency measures. Meanwhile, surface EMG signals obviously differ from their surrogate data at higher sampling frequencies. The results indicate that surface EMG signals contain nonlinear components. To gather the sufficient information of surface EMG signal, the data acquisition should be required at the higher sampling frequency. Furthermore, the nonlinear measure based on symplectic geometry can be used as a sensitive index for evaluation of the activity of the human muscles.
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Dexamethasone Increases Cdc42 Expression in Human TM-1 Cells.
Curr. Eye Res.
PUBLISHED: 05-30-2014
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Abstract Purpose: Changes in the cytoskeletal organization of the human trabecular meshwork (HTM) is thought to be responsible for primary open-angle glaucoma (POAG) pathologies. Cdc42 is a Rho GTPase; Rho GTPases are important modulatory agents of the cytoskeleton. This study aimed to investigate the effects of dexamethasone (DEX) on Cdc42 in a transformed HTM cell line, TM-1 to understand the molecular pathologies underlying POAG. Methods: TM-1 cells were cultured in vitro. The cultures were treated with DEX at 10(-6) and 10(-7)?M for 1-4 days. Cdc42 was silenced using small interfering RNA (siRNA). The expression levels of Cdc42 in the TM-1 cells were measured using reverse transcription (RT)-PCR, western blotting analysis and immunofluorescence. Its downstream effectors, p21-activated kinase phosphorylation (phospho-PAK) and myosin light chain kinase (MLCK), were measured using western blotting analysis. In addition, the F-actin of TM-1 cells was stained using phalloidin. Results: The mRNA and protein levels of Cdc42 showed an increase in TM-1 cells with DEX treatment and a decrease in TM-1 cells transfected with Cdc42 siRNA. Moreover, phospho-PAK levels increased, whereas MLCK levels appeared to decrease, with DEX treatment. The F-actin of DEX-treated TM-1 cells displayed a rearrangement. Cdc42 siRNA decreased the expression of Cdc42 and its related proteins, resulting in an attenuation of the effects of DEX on Cdc42 and F-actin organization in TM-1 cells. Conclusions: DEX increases Cdc42 expression in TM-1. This may represent a potential mechanism of DEX-induced HTM cytoskeletal rearrangement.
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Vapor-condensation-assisted optical microscopy for ultralong carbon nanotubes and other nanostructures.
Nano Lett.
PUBLISHED: 05-28-2014
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Here we present a simple yet powerful approach for the imaging of nanostructures under an optical microscope with the help of vapor condensation on their surfaces. Supersaturated water vapor will first form a nanometer-sized water droplet on the condensation nuclei on the surface of nanostructures, and then the water droplet will grow bigger and scatter more light to make the outline of the nanostructure be visible under dark-field optical microscope. This vapor-condensation-assisted (VCA) optical microscopy is applicable to a variety of nanostructures from ultralong carbon nanotubes to functional groups, generating images with contrast coming from the difference in density of the condensation sites, and does not induce any impurities to the specimens. Moreover, this low-cost and efficient technique can be conveniently integrated with other facilities, such as Raman spectroscope and so forth, which will pave the way for widespread applications.
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Connexin 31.1 degradation requires the Clathrin-mediated autophagy in NSCLC cell H1299.
J. Cell. Mol. Med.
PUBLISHED: 05-08-2014
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Connexins have relative short half-lives. Connexin 31.1 (Cx31.1) was newly reported to be down-regulated in non-small cell lung cancer cell lines, and displayed tumour-suppressive properties. However, no reports describing how a cell regulates Cx31.1 level were found. In this study, Cx31.1 was suggested to be degraded through both ubiquitin-proteasome system (UPS) and autophagy. Blockage of UPS with MG-132 increased Cx31.1 level, but could not inhibit the degradation of Cx31.1 completely. In H1299 cells stably expressing Cx31.1, Cx31.1 reduced when autophagy was induced through starvation or Brefeldin A treatment. Knockdown of autophagy-related protein ATG5 could increase the cellular level of Cx31.1 both under normal growth condition and starvation-induced autophagy. Colocalization of Cx31.1 and autophagy marker light chain 3 (LC3) was revealed by immunofluorescence analysis. Coimmunoprecipitation and immunofluorescence showed that Cx31.1 might interact with clathrin heavy chain which was newly reported to regulate autophagic lysosome reformation (ALR) and controls lysosome homoeostasis. When clathrin expression was knockdown by siRNA treatment, the level of Cx31.1 increased prominently both under normal growth condition and starvation-induced autophagy. Under starvation-induced autophagy, LC3-II levels were slightly accumulated with siCla. treatment compared to that of siNC, which could be ascribed to that clathrin knockdown impaired the late stage of autophagy, ALR. Taken together, we found autophagy contributed to Cx31.1 degradation, and clathrin might be involved in the autophagy of Cx31.1.
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RAID: a comprehensive resource for human RNA-associated (RNA-RNA/RNA-protein) interaction.
RNA
PUBLISHED: 05-06-2014
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Transcriptomic analyses have revealed an unexpected complexity in the eukaryote transcriptome, which includes not only protein-coding transcripts but also an expanding catalog of noncoding RNAs (ncRNAs). Diverse coding and noncoding RNAs (ncRNAs) perform functions through interaction with each other in various cellular processes. In this project, we have developed RAID (http://www.rna-society.org/raid), an RNA-associated (RNA-RNA/RNA-protein) interaction database. RAID intends to provide the scientific community with all-in-one resources for efficient browsing and extraction of the RNA-associated interactions in human. This version of RAID contains more than 6100 RNA-associated interactions obtained by manually reviewing more than 2100 published papers, including 4493 RNA-RNA interactions and 1619 RNA-protein interactions. Each entry contains detailed information on an RNA-associated interaction, including RAID ID, RNA/protein symbol, RNA/protein categories, validated method, expressing tissue, literature references (Pubmed IDs), and detailed functional description. Users can query, browse, analyze, and manipulate RNA-associated (RNA-RNA/RNA-protein) interaction. RAID provides a comprehensive resource of human RNA-associated (RNA-RNA/RNA-protein) interaction network. Furthermore, this resource will help in uncovering the generic organizing principles of cellular function network.
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A colloidal gold nanoparticle-based immunochromatographic test strip for rapid and convenient detection of Staphylococcus aureus.
J Nanosci Nanotechnol
PUBLISHED: 04-25-2014
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An immunochromatographic test strip using gold nanoparticles-staphylococcus aureus monoclonal antibody conjugates was developed for the rapid and convenient detection of staphylococcus aureus based on a double-antibody sandwich format. The detection limit and the detection rate of this test strip is 10(3) CFU /mL and 98.7%, respectively. It could be used for the rapid detection of staphylococcus aureus in food and the results can be visually identified by the naked eye within 10 min. Compared with conventional bacterial detection methods, this developed immunochromatographic assay based test strip has several advantages including simple, fast, low-cost, favorable sensitivity and specificity, exhibiting a great potential for application in food safety control systems and clinical diagnosis.
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Multidimensional mapping of spin-exchange optical pumping in clinical-scale batch-mode 129Xe hyperpolarizers.
J Phys Chem B
PUBLISHED: 04-25-2014
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We present a systematic, multiparameter study of Rb/(129)Xe spin-exchange optical pumping (SEOP) in the regimes of high xenon pressure and photon flux using a 3D-printed, clinical-scale stopped-flow hyperpolarizer. In situ NMR detection was used to study the dynamics of (129)Xe polarization as a function of SEOP-cell operating temperature, photon flux, and xenon partial pressure to maximize (129)Xe polarization (PXe). PXe values of 95 ± 9%, 73 ± 4%, 60 ± 2%, 41 ± 1%, and 31 ± 1% at 275, 515, 1000, 1500, and 2000 Torr Xe partial pressure were achieved. These PXe polarization values were separately validated by ejecting the hyperpolarized (129)Xe gas and performing low-field MRI at 47.5 mT. It is shown that PXe in this high-pressure regime can be increased beyond already record levels with higher photon flux and better SEOP thermal management, as well as optimization of the polarization dynamics, pointing the way to further improvements in hyperpolarized (129)Xe production efficiency.
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Collagen/Wollastonite nanowire hybrid scaffolds promoting osteogenic differentiation and angiogenic factor expression of mesenchymal stem cells.
J Nanosci Nanotechnol
PUBLISHED: 04-17-2014
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Porous materials and scaffolds have wide applications in biomedical and biological fields. They can provide biological and physical cues to promote cell adhesion, proliferation, differentiation and extracellular matrix secretion to guide new tissue formation. Hybrid scaffolds of collagen and wollastonite nanowires with well controlled pore structures were prepared by using ice particulates as a porogen material. The hybrid scaffolds had interconnected large spherical pores with wollastonite nanowires embedded in the walls of the pores. The wollastonite nanowires reinforced the hybrid scaffolds and showed some stimulatory effects on cell functions. Human bone marrow-derived mesenchymal stem cells showed higher proliferation and osteogenic differentiation and expressed higher level of genes encoding angiogenesis-related genes in the hybrid scaffolds than did in the collagen scaf-. fold. The results suggest the hybrid scaffolds could facilitate osteogenic differentiation and induce angiogenesis and will be useful for bone tissue engineering.
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Implementation of blind source separation for optical fiber sensing.
Appl Opt
PUBLISHED: 03-26-2014
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Blind source separation (BSS) is implemented for optical fiber sensing systems, such as the fiber Bragg grating (FBG) sensing system and the single-mode-multimode-single-mode fiber (SMS) sensing system. The FastICA, a kind of multichannel BSS algorithm, is used to get the strain and the temperature with two FBGs. For the SMS sensing, a single-channel blind source separation (SCBSS) algorithm is employed to simultaneously measure the vibration and the temperature variation with only one SMS sensor. The errors of both the FBG and the SMS optical fiber sensing system are very small with the BSS algorithm. The implementation of BSS for the optical fiber sensing makes the multiparameter measurements more easily with low cost and high accuracy and can also be applied for signal de-noising field.
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Nanostructured energetic composites: synthesis, ignition/combustion modeling, and applications.
ACS Appl Mater Interfaces
PUBLISHED: 02-28-2014
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Nanotechnology has stimulated revolutionary advances in many scientific and industrial fields, particularly in energetic materials. Powder mixing is the simplest and most traditional method to prepare nanoenergetic composites, and preliminary findings have shown that these composites perform more effectively than their micro- or macro-sized counterparts in terms of energy release, ignition, and combustion. Powder mixing technology represents only the minimum capability of nanotechnology to boost the development of energetic material research, and it has intrinsic limitations, namely, random distribution of fuel and oxidizer particles, inevitable fuel pre-oxidation, and non-intimate contact between reactants. As an alternative, nanostructured energetic composites can be prepared through a delicately designed process. These composites outperform powder-mixed nanocomposites in numerous ways; therefore, we comprehensively discuss the preparation strategies adopted for nanostructured energetic composites and the research achievements thus far in this review. The latest ignition and reaction models are briefly introduced. Finally, the broad promising applications of nanostructured energetic composites are highlighted.
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The role of the RhoA/Rho kinase pathway in angiogenesis and its potential value in prostate cancer (Review).
Oncol Lett
PUBLISHED: 02-25-2014
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Prostate cancer (PCa) remains a major cause of mortality among males in western countries, with little change in mortality rates observed over the past 25 years. Despite recent advances in therapy, treatment options for metastatic castration-resistant disease remain limited. In terms of chemotherapy, only the combination of docetaxel and prednisone has been shown to improve survival in these patients, but duration of response to therapy is short. There is a continuing unmet need for new systemic interventions that act either alone or synergistically with chemotherapy in patients with progressive PCa. Angiogenesis plays a critical role in tumor growth and metastasis in PCa. Several strategies have been used to target angiogenesis; however, it is becoming increasingly apparent that current anti-angiogenic therapies frequently achieve only modest effects in clinical settings. The RhoA/Rho kinase (ROCK) pathway plays a crucial role in the process of angiogenesis in PCa, and studies have demonstrated that ROCK inhibitors decrease VEGF-induced angiogenesis and tumor cell growth. However, further research is required to fully elucidate the molecular mechanisms involved in this pathway, and the potential value of modulating these mechanisms in the treatment of PCa. This study reviews the current understanding of the role of the RhoA/ROCK pathway in the process of angiogenesis in PCa, and the potential of this pathway as a therapeutic target in the future.
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Production of fumaric acid from biodiesel-derived crude glycerol by Rhizopus arrhizus.
Bioresour. Technol.
PUBLISHED: 02-25-2014
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This work investigated the capability of Rhizopus arrhizus to assimilate biodiesel-derived crude glycerol and convert it into fumaric acid. After optimizing the initial glycerol concentration, spore inoculum and yeast extract concentration, smaller pellets (0.7 mm) and higher biomass (3.11 g/L) were obtained when R. arrhizus grew on crude glycerol. It was found that crude glycerol was more suitable than glucose for smaller R. arrhizus pellet forming. When 80 g/L crude glycerol was used as carbon source, the fumaric acid production of 4.37 g/L was obtained at 192 h. With a highest concentration of 22.81 g/L achieved in the co-fermentation of crude glycerol (40 g/L) and glucose (40 g/L) at 144 h, the fumaric acid production was enhanced by 553.6%, compared to the fermentation using glycerol (80 g/L) as sole carbon source. Moreover, the production cost of fumaric acid in co-fermentation was reduced by approximately 14% compared to glucose fermentation.
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Advances in synthesis of calcium phosphate crystals with controlled size and shape.
Acta Biomater
PUBLISHED: 02-24-2014
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Calcium phosphate (CaP) materials have a wide range of applications, including biomaterials, adsorbents, chemical engineering materials, catalysts and catalyst supports and mechanical reinforcements. The size and shape of CaP crystals and aggregates play critical roles in their applications. The main inorganic building blocks of human bones and teeth are nanocrystalline CaPs; recently, much progress has been made in the application of CaP nanocrystals and their composites for clinical repair of damaged bone and tooth. For example, CaPs with special micro- and nanostructures can better imitate the biomimetic features of human bone and tooth, and this offers significantly enhanced biological performances. Therefore, the design of CaP nano-/microcrystals, and the shape and hierarchical structures of CaPs, have great potential to revolutionize the field of hard tissue engineering, starting from bone/tooth repair and augmentation to controlled drug delivery devices. Previously, a number of reviews have reported the synthesis and properties of CaP materials, especially for hydroxyapatite (HAp). However, most of them mainly focused on the characterizations and physicochemical and biological properties of HAp particles. There are few reviews about the control of particle size and size distribution of CaPs, and in particular the control of nano-/microstructures on bulk CaP ceramic surfaces, which is a big challenge technically and may have great potential in tissue engineering applications. This review summarizes the current state of the art for the synthesis of CaP crystals with controlled sizes from the nano- to the macroscale, and the diverse shapes including the zero-dimensional shapes of particles and spheres, the one-dimensional shapes of rods, fibers, wires and whiskers, the two-dimensional shapes of sheets, disks, plates, belts, ribbons and flakes and the three-dimensional (3-D) shapes of porous, hollow, and biomimetic structures similar to biological bone and tooth. In addition, this review will also summarize studies on the controlled formation of nano-/microstructures on the surface of bulk ceramics, and the preparation of macroscopical bone grafts with 3-D architecture nano-/microstructured surfaces. Moreover, the possible directions of future research and development in this field, such as the detailed mechanisms behind the size and shape control in various strategies, the importance of theoretical simulation, self-assembly, biomineralization and sacrificial precursor strategies in the fabrication of biomimetic bone-like and enamel-like CaP materials are proposed.
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Content and molecular weight of water-extractable arabinoxylans in wheat malt and wheat malt-based wort with different Kolbach indices.
J. Sci. Food Agric.
PUBLISHED: 02-13-2014
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Arabinoxylans (AXs) are partially water-extractable polymers that cause problems of viscosity and filterability during beer brewing. This study investigated the effects of Kolbach index (KI) on water-extractable AXs (WEAXs).
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Growth of hierarchical 3D mesoporous NiSix /NiCo2 O4 core/shell heterostructures on nickel foam for lithium-ion batteries.
ChemSusChem
PUBLISHED: 02-09-2014
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We demonstrate the facile and well-controlled design and fabrication of heterostructured and hierarchical 3D mesoporous NiSix /NiCo2 O4 core/shell nanowire arrays on nickel foam through a facile chemical vapor deposition (CVD) technique combined with a simple but powerful chemical bath deposition (CBD) technique. The smart hybridization of NiCo2 O4 and NiSix nanostructures results in an intriguing mesoporous hierarchical core/shell nanowire-array architecture. The nanowire arrays demonstrate enhanced electrochemical performance as binder- and conductive-agent-free electrodes for lithium ion batteries (LIBs) with excellent capacity retention and high rate capability on cycling. The electrodes can maintain a high reversible capacity of 1693 mA h g(-1) after 50 cycles at 20 mA g(-1) . Given the outstanding performance and simple, efficient, cost-effective fabrication, we believe that these 3D NiSix /NiCo2 O4 core/shell heterostructured arrays have great potential application in high-performance LIBs.
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Simultaneous determination of mequindox, quinocetone, and their major metabolites in chicken and pork by UPLC-MS/MS.
Food Chem
PUBLISHED: 02-08-2014
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This report presents a UPLC-MS/MS method for determination of mequindox (MEQ), quinocetone (QCT) and their 11 metabolites in chicken and pork samples. Following extraction process with acetonitrile-ethyl acetate, acidulation, and re-extraction with ethyl acetate in turn, target analytes were further purified using C18 solid phase extraction (SPE) cartridges for UPLC-MS/MS analysis. Validation was processed with mean recoveries from 69.1% to 113.3% with intra-day relative standard deviation (RSD) <14.7%, inter-day RSD <19.2%, and limit of detection between 0.05 and 1.0 ?g/kg for each analytes. The verified method was successfully applied to the quantitative determination of commercial samples. This developed procedure will help to control food animal products with MEQ and QCT residues, and facilitate further pharmacokinetic and residue studies of similar quinoxaline-1,4-dioxide veterinary drugs.
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Genetic influence on family socioeconomic status and children's intelligence.
Intelligence
PUBLISHED: 02-04-2014
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Environmental measures used widely in the behavioral sciences show nearly as much genetic influence as behavioral measures, a critical finding for interpreting associations between environmental factors and children's development. This research depends on the twin method that compares monozygotic and dizygotic twins, but key aspects of children's environment such as socioeconomic status (SES) cannot be investigated in twin studies because they are the same for children growing up together in a family. Here, using a new technique applied to DNA from 3000 unrelated children, we show significant genetic influence on family SES, and on its association with children's IQ at ages 7 and 12. In addition to demonstrating the ability to investigate genetic influence on between-family environmental measures, our results emphasize the need to consider genetics in research and policy on family SES and its association with children's IQ.
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XeNA: an automated 'open-source' (129)Xe hyperpolarizer for clinical use.
Magn Reson Imaging
PUBLISHED: 01-30-2014
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Here we provide a full report on the construction, components, and capabilities of our consortium's "open-source" large-scale (~1L/h) (129)Xe hyperpolarizer for clinical, pre-clinical, and materials NMR/MRI (Nikolaou et al., Proc. Natl. Acad. Sci. USA, 110, 14150 (2013)). The 'hyperpolarizer' is automated and built mostly of off-the-shelf components; moreover, it is designed to be cost-effective and installed in both research laboratories and clinical settings with materials costing less than $125,000. The device runs in the xenon-rich regime (up to 1800Torr Xe in 0.5L) in either stopped-flow or single-batch mode-making cryo-collection of the hyperpolarized gas unnecessary for many applications. In-cell (129)Xe nuclear spin polarization values of ~30%-90% have been measured for Xe loadings of ~300-1600Torr. Typical (129)Xe polarization build-up and T1 relaxation time constants were ~8.5min and ~1.9h respectively under our spin-exchange optical pumping conditions; such ratios, combined with near-unity Rb electron spin polarizations enabled by the high resonant laser power (up to ~200W), permit such high PXe values to be achieved despite the high in-cell Xe densities. Importantly, most of the polarization is maintained during efficient HP gas transfer to other containers, and ultra-long (129)Xe relaxation times (up to nearly 6h) were observed in Tedlar bags following transport to a clinical 3T scanner for MR spectroscopy and imaging as a prelude to in vivo experiments. The device has received FDA IND approval for a clinical study of chronic obstructive pulmonary disease subjects. The primary focus of this paper is on the technical/engineering development of the polarizer, with the explicit goals of facilitating the adaptation of design features and operative modes into other laboratories, and of spurring the further advancement of HP-gas MR applications in biomedicine.
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Phase II trial of bortezomib alone or in combination with irinotecan in patients with adenocarcinoma of the gastroesophageal junction or stomach.
Invest New Drugs
PUBLISHED: 01-28-2014
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To determine the effectiveness of bortezomib plus irinotecan and bortezomib alone in patients with advanced gastroesophageal junction (GEJ) and gastric adenocarcinoma. We also sought to explore the effect of these therapeutics on tumor and normal gene expression in vivo.
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Clinical pathologies of breast cancer in the elderly and youths and their prognosis.
Pak J Med Sci
PUBLISHED: 01-21-2014
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To explore the correlation between the clinical pathologies of breast cancer in the elderly and youths as well as their prognosis.
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Highly sensitive and quantitative human thrombospondin-1 detection by an M55 aptasensor and clinical validation in patients with atherosclerotic disease.
Biosens Bioelectron
PUBLISHED: 01-18-2014
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Aptamer-based biosensors (aptasensor) are powerful tools for rapid and sensitive biomarker detection. In this study, we report a DNA aptamer probe evolved from cell-SELEX that can recognize thrombospondin-1 protein in human plasma samples. The KD value of the aptamer M55 binding to thrombospondin-1 was determined as 0.5 ± 0.2 ?M with an R(2) of 0.9144. A horseradish peroxidase-linked short oligo was complementarily bound onto the 3' end of the aptamer sequence to facilitate the 'smart' design of an M55-aptasensor for quantifying thrombospondin-1 protein in plasma samples. The limit of detection was 6.96 fM. Thrombospondin-1 is a glycoprotein with multiple biological functions, including inflammation, platelet aggregation and endothelial cell apoptosis, and is involved in the pathology of atherosclerosis. In total, 118 plasma subjects were analyzed by using the aptasensor measurement with 1 ?L sample volume and 5 min incubation time. The thrombospondin-1 concentrations in ST-Elevation Myocardial Infarction patients with severe atherosclerotic plaque burden were statistically significantly higher than in the healthy volunteers without atherosclerosis conditions, suggesting that thromboposnidn-1 is a potential plasma biomarker for atherosclerosis progression.
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Enhanced optical output power of blue light-emitting diodes with quasi-aligned gold nanoparticles.
Nanoscale Res Lett
PUBLISHED: 01-06-2014
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The output power of the light from GaN-based light-emitting diodes (LEDs) was enhanced by fabricating gold (Au) nanoparticles on the surface of p-GaN. Quasi-aligned Au nanoparticle arrays were prepared by depositing Au thin film on an aligned suspended carbon nanotube thin film surface and then putting the Au-CNT system on the surface of p-GaN and thermally annealing the sample. The size and position of the Au nanoparticles were confined by the carbon nanotube framework, and no other additional residual Au was distributed on the surface of the p-GaN substrate. The output power of the light from the LEDs with Au nanoparticles was enhanced by 55.3% for an injected current of 100 mA with the electrical property unchanged compared with the conventional planar LEDs. The enhancement may originate from the surface plasmon effect and scattering effect of the Au nanoparticles.
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Hydrothermal synthesis and characterization of Si and Sr co-substituted hydroxyapatite nanowires using strontium containing calcium silicate as precursors.
Mater Sci Eng C Mater Biol Appl
PUBLISHED: 01-05-2014
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In the absence of any organic surfactants and solvents, the silicon (Si) and strontium (Sr) co-substituted hydroxyapatite [Ca10(PO4)6(OH)2, Si/Sr-HAp] nanowires were synthesized via hydrothermal treatment of the Sr-containing calcium silicate (Sr-CS) powders as the precursors in trisodium phosphate (Na3PO4) aqueous solution. The morphology, phase, chemical compositions, lattice constants and the degradability of the products were characterized. The Si/Sr-HAp nanowires with diameter of about 60nm and up to 2?m in length were obtained after hydrothermal treatment of the Sr-CS precursors. The Sr and Si substitution amount of the HAp nanowires could be well regulated by facile tailoring the Sr substitution level of the precursors and the reaction ratio of the precursor/solution, respectively. The SiO4 tetrahedra and Sr(2+) ions occupied the crystal sites of the HAp, and the lattice constants increased apparently with the increase of the substitution amount. EDS mapping also suggested the uniform distribution of Si and Sr in the synthetic nanowires. Moreover, the Si/Sr-substitution apparently improved the degradability of the HAp materials. Our study suggested that the precursor transformation method provided a facile approach to synthesize the Si/Sr co-substituted HAp nanowires with controllable substitution amount, and the synthetic Si/Sr-HAp nanowires might be used as bioactive materials for hard tissue regeneration applications.
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Enhancement of oral bioavailability of cyclosporine A: comparison of various nanoscale drug-delivery systems.
Int J Nanomedicine
PUBLISHED: 01-01-2014
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A variety of nanoscale delivery systems have been shown to enhance the oral absorption of poorly water-soluble and poorly permeable drugs. However, the performance of these systems has seldom been evaluated simultaneously. The aim of this study was to compare the bioavailability enhancement effect of lipid-based nanocarriers with poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) to highlight the importance of the lipid composition, with cyclosporine A (CyA) as a model drug. CyA-loaded PLGA NPs, nanostructured lipid carriers (NLCs), and self-microemulsifying drug-delivery systems (SMEDDS) were prepared. The particle size of PLGA NPs (182.2 ± 12.8 nm) was larger than that of NLCs (89.7 ± 9.0 nm) and SMEDDS (26.9 ± 1.9 nm). All vehicles are charged negatively. The entrapment efficiency of PLGA NPs and NLCs was 87.6%± 1.6% and 80.3%± 0.6%, respectively. In vitro release tests indicated that the cumulative release of CyA was lower than 4% from all vehicles, including Sandimmun Neoral(®), according to the dialysis method. Both NLCs and SMEDDS showed high relative oral bioavailability, 111.8% and 73.6%, respectively, after oral gavage administration to beagle dogs, which was not statistically different from commercial Sandimmun Neoral(®). However, PLGA NPs failed to achieve efficient absorption, with relative bioavailability of about 22.7%. It is concluded that lipid-based nanoscale drug-delivery systems are superior to polymeric NPs in enhancing oral bioavailability of poorly water-soluble and poorly permeable drugs.
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A novel cellular senescence gene, SENEX, is involved in peripheral regulatory T cells accumulation in aged urinary bladder cancer.
PLoS ONE
PUBLISHED: 01-01-2014
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Regulatory T cells (Tregs) play an essential role in sustaining self-tolerance and immune homeostasis. Despite many studies on the correlation between Tregs accumulation and age, or malignancies, the related mechanism hasn't been well explored. To find out the mechanism of Tregs accumulation in aged urinary bladder cancer, we examined the novel cellular senesence gene SENEX and relevant apoptosis gene mRNA expression in sorted CD4+CD25(hi) Tregs from aged UBC donors, evaluated serum cytokine profiles related to tumor immunopathology, and further explored the relationship between SENEX expression, apoptosis gene expression and cytokine secretion. After having silenced down SENEX gene expression with RNA interference, we also evaluated the cellular apoptosis of Tregs sorted from aged UBC patients in response to H?O?-mediated stress. Our data indicated that upregulated SENEX mRNA expression in Tregs of aged UBC patients was correlated with pro-apoptotic gene expression and cytokine concentration. Silencing SENEX gene expression increased cellular apoptosis and pro-apoptotic gene expression of Tregs, in response to H?O?-mediated stress. Upregulated SENEX mRNA expression together with decreased pro-apoptotic gene expression and disturbances in cytokines synthesis may contribute to the Tregs proliferation and promote tumorigenesis and metastasis. Overall, upregulation of cellular senescence gene SENEX, was associated to regulatory T cells accumulation in aged urinary bladder cancer. Our study provides a new insight into understanding of peripheral Tregs accumulation in aged malignancies.
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The Dependence of Graphene Raman D-band on Carrier Density.
Nano Lett.
PUBLISHED: 12-03-2013
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Raman spectroscopy has been an integral part of graphene research and can provide information about graphene structure, electronic characteristics, and electron-phonon interactions. In this study, the characteristics of the graphene Raman D-band, which vary with carrier density, are studied in detail, including the frequency, full width half-maximum, and intensity. We find the Raman D-band frequency increases for hole doping and decreases for electron doping. The Raman D-band intensity increases when the Fermi level approaches half of the excitation energy and is higher in the case of electron doping than that of hole doping. These variations can be explained by electron-phonon interaction theory and quantum interference between different Raman pathways in graphene. The intensity ratio of Raman D- and G-band, which is important for defects characterization in graphene, shows a strong dependence on carrier density.
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Evaluating bandgap distributions of carbon nanotubes via scanning electron microscopy imaging of the Schottky barriers.
Nano Lett.
PUBLISHED: 10-22-2013
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We show that the Schottky barrier at the metal-single walled carbon nanotube (SWCNT) contact can be clearly observed in scanning electron microscopy (SEM) images as a bright contrast segment with length up to micrometers due to the space charge distribution in the depletion region. The lengths of the charge depletion increase with the diameters of semiconducting SWCNTs (s-SWCNTs) when connected to one metal electrode, which enables direct and efficient evaluation of the bandgap distributions of s-SWCNTs. Moreover, this approach can also be applied for a wide variety of semiconducting nanomaterials, adding a new function to conventional SEM.
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Azacrown[N,S,O]-modified porphyrin sensor for detection of Ag+, Pb2+, and Cu2+.
Photochem. Photobiol. Sci.
PUBLISHED: 09-24-2013
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One new azacrown[N,S,O]-modified metal-free porphyrin derivative, H2Por-azacrown (1), with the central tetrapyrrole moiety as signaling fluorophore and/or metal ion receptor has been designed, synthesized, and characterized. Addition of Ag(+) into this novel metal-free porphyrin compound induces a fluorescence ON-OFF process, while adding Pb(2+) leads to absorption/emission-ratiometric signals. Quite interestingly, blue-shift of the Soret band, ratiometric change of Q bands, and dual-signal changes (absorption ratio and fluorescence ON-OFF) associated with the Cu(2+) displacement from the 1-Pb(2+) system were observed upon addition of Cu(2+). These results render this H2Por-azacrown compound a porphyrin-based multi-responsive optical sensor towards Ag(+), Pb(2+), and in particular Cu(2+) with dual-mode detecting potential.
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Thermoacoustic chips with carbon nanotube thin yarn arrays.
Nano Lett.
PUBLISHED: 09-18-2013
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Aligned carbon nanotube (CNT) films drawn from CNT arrays have shown the potential as thermoacoustic loudspeakers. CNT thermoacoustic chips with robust structures are proposed to promote the applications. The silicon-based chips can play sound and fascinating rhythms by feeding alternating currents and audio signal to the suspending CNT thin yarn arrays across grooves in them. In additional to the thin yarns, experiments further revealed more essential elements of the chips, the groove depth and the interdigital electrodes. The sound pressure depends on the depth of the grooves, and the thermal wavelength can be introduced to define the influence-free depth. The interdigital fingers can effectively reduce the driving voltage, making the chips safe and easy to use. The chips were successfully assembled into earphones and have been working stably for about one year. The thermoacoustic chips can find many applications in consumer electronics and possibly improve the audiovisual experience.
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What I look like: college women, body image, and spirituality.
J Relig Health
PUBLISHED: 09-11-2013
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Despite public acknowledgment of the importance of spiritual development, little has been written globally on female young adults personal views of their spiritual values and body image. This article briefly presents the findings of a pilot study that explored female college students reflections on body image and spirituality. Responses from participants showed that (1) many students are interested in faith and spiritual development; (2) body dissatisfaction affects those women who viewed themselves as spiritual (92%) as well as those who said they were free thinkers (49%). Nevertheless, religion and spiritual values seemed to confer some behavioral protection. Implications for educational programs that will address the spiritual dimension of learning are discussed.
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The realistic domain structure of as-synthesized graphene oxide from ultrafast spectroscopy.
J. Am. Chem. Soc.
PUBLISHED: 08-12-2013
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Graphene oxide (GO) is an attractive alternative for large-scale production of graphene, but its general structure is still under debate due to its complicated nonstoichiometric nature. Here we perform a set of femtosecond pump-probe experiments on as-synthesized GO to extrapolate structural information in situ. Remarkably, it is observed that, in these highly oxidized GO samples, the ultrafast graphene-like dynamics intrinsic to pristine graphene is completely dominant over a wide energy region and can be modified by the localized impurity states and the electron-phonon coupling under certain conditions. These observations, combined with the X-ray photoelectron spectroscopy analysis and control experiments, lead to an important conclusion that GO consists of two types of domain, namely the carbon-rich graphene-like domain and the oxygen-rich domain. This study creates a new understanding of the realistic domain structure and properties of as-synthesized GO, offering useful guidance for future applications based on chemically modified/functionalized graphenes.
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In Situ Synthesis of CuO and Cu Nanostructures with Promising Electrochemical and Wettability Properties.
Small
PUBLISHED: 08-02-2013
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A strategy is presented for the in situ synthesis of single crystalline CuO nanorods and 3D CuO nanostructures, ultra-long Cu nanowires and Cu nanoparticles at relatively low temperature onto various substrates (Si, SiO2 , ITO, FTO, porous nickel, carbon cotton, etc.) by one-step thermal heating of copper foam in static air and inert gas, respectively. The density, particle sizes and morphologies of the synthesized nanostructures can be effectively controlled by simply tailoring the experimental parameters. A compressive stress based and subsequent structural rearrangements mechanism is proposed to explain the formation of the nanostructures. The as-prepared CuO nanostructures demonstrate promising electrochemical properties as the anode materials in lithium-ion batteries and also reversible wettability. Moreover, this strategy can be used to conveniently integrate these nanostructures with other nanostructures (ZnO nanorods, Co3 O4 nanowires and nanowalls, TiO2 nanotubes, and Si nanowires) to achieve various hybrid hierarchical (CuO-ZnO, CuO-Co3 O4 , CuO-TiO2 , CuO-Si) nanocomposites with promising properties. This strategy has the potential to provide the nano society with a general way to achieve a variety of nanostructures.
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Tailoring the nanostructured surfaces of hydroxyapatite bioceramics to promote protein adsorption, osteoblast growth, and osteogenic differentiation.
ACS Appl Mater Interfaces
PUBLISHED: 08-01-2013
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To promote and understand the biological responses of the implant via nanostructured surface design is essential for the development of bioactive bone implants. However, the control of the surface topography of the bioceramics in nanoscale is a big challenge because of their brittle property. Herein, the hydroxyapatite (HAp) bioceramics with distinct nanostructured topographies were fabricated via hydrothermal treatment using ?-tricalcium phosphate ceramic as hard-template under different reaction conditions. HAp bioceramics with nanosheet, nanorod and micro-nanohybrid structured surface in macroscopical size were obtained by controlling the composition of the reaction media. Comparing with the traditional sample with flat and dense surface, the fabricated HAp bioceramics with hierarchical 3D micro-nanotextured surfaces possessed higher specific surface area, which selectively enhanced adsorption of specific proteins including Fn and Vn in plasma, and stimulated osteoblast adhesion, growth, and osoteogenic differentiation. In particular, the biomimetic features of the hierarchical micro-nanohybrid surface resulted in the best ability for simultaneous enhancement of protein adsorption, osteoblast proliferation, and differentiation. The results suggest that the hierarchical micro-nanohybrid topography might be one of the critical factors to be considered in the design of functional bone grafts.
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Effects of particle size on the pharmacokinetics of puerarin nanocrystals and microcrystals after oral administration to rat.
Int J Pharm
PUBLISHED: 07-31-2013
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Puerarin, which is extracted from traditional Chinese medicine, is widely used in clinic in China and mainly used as a therapeutic agent to cardiovascular diseases. Owing to its poor water solubility and adverse drug reactions caused by cosolvents after intravenous administration, the development of oral formulation is urgently needed. Nowadays, nanocrystals technique has become a preferred way to develop oral dosage form. In this study, we used high pressure homogenization (HPH) to prepare puerarin nanocrystals and microcrystals with different sizes ranged from 525.8 nm to 1875.6 nm and investigated the influence of particle size on pharmacokinetics. The nanocrystals and microcrystals prepared were characterized using DLS, DSC, XRD and SEM, and we found that the crystalline state of puerarin was changed during the preparation process and the drug was dispersed into HPMC. In the pharmacokinetic study, we observed an increasing of Cmax and AUC and a decreasing of CL/F with the decreasing of particle size. The AUC of the puerarin nanocrystals (525.8 nm) was 7.6-fold of that of raw puerarin suspension, with an absolute bioavailability of 21.44%. From the above results, we can conclude that nanocrystal technique is an efficient technology to improve the oral bioavailability of puerarin.
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Facile green in situ synthesis of Mg/CuO core/shell nanoenergetic arrays with a superior heat-release property and long-term storage stability.
ACS Appl Mater Interfaces
PUBLISHED: 07-31-2013
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We report a facile green method for the in situ synthesis of Mg/CuO core/shell nanoenergetic arrays on silicon, with Mg nanorods as the core and CuO as the shell. Mg nanorods are first prepared by glancing angle deposition. CuO is then deposited around the Mg nanorods by reactive magnetron sputtering to realize the core/shell structure. Various characterization techniques are used to investigate the prepared Mg/CuO core/shell nanoenergetic arrays, including scanning electron microscopy, transmission electron microscopy, X-ray energy dispersive spectroscopy, X-ray diffraction, and thermal analysis. Uniform mixing and intimate contact between the Mg nanorods and CuO are confirmed from both visual inspection of the morphological images and analyses of the heat-release curves. The nanoenergetic arrays exhibit a low-onset reaction temperature (?300 °C) and high heat of reaction (?3400 J/g). Most importantly, the nanoenergetic arrays possess long-term storage stability resulting from the stable CuO shell. This study provides a potential general strategy for the synthesis of various Mg nanorod-based stable nanoenergetic arrays.
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Development of an ultra-thin film comprised of a graphene membrane and carbon nanotube vein support.
Nat Commun
PUBLISHED: 07-26-2013
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Graphene, exhibiting superior mechanical, thermal, optical and electronic properties, has attracted great interest. Considering it being one-atom-thick, and the reduced mechanical strength at grain boundaries, the fabrication of large-area suspended chemical vapour deposition graphene remains a challenge. Here we report the fabrication of an ultra-thin free-standing carbon nanotube/graphene hybrid film, inspired by the vein-membrane structure found in nature. Such a square-centimetre-sized hybrid film can realize the overlaying of large-area single-layer chemical vapour deposition graphene on to a porous vein-like carbon nanotube network. The vein-membrane-like hybrid film, with graphene suspended on the carbon nanotube meshes, possesses excellent mechanical performance, optical transparency and good electrical conductivity. The ultra-thin hybrid film features an electron transparency close to 90%, which makes it an ideal gate electrode in vacuum electronics and a high-performance sample support in transmission electron microscopy.
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Enhanced osteoporotic bone regeneration by strontium-substituted calcium silicate bioactive ceramics.
Biomaterials
PUBLISHED: 07-23-2013
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The regeneration capacity of the osteoporotic bones is generally lower than that of the normal bones. Current methods of bone defect treatment for osteoporosis are not always satisfactory. Recent studies have shown that the silicate based biomaterials can stimulate osteogenesis and angiogenesis due to the silicon (Si) ions released from the materials, and enhance bone regeneration in vivo. Other studies showed that strontium (Sr) plays a distinct role on inhibiting bone resorption. Based on the hypothesis that the combination of Si and Sr may have synergetic effects on osteoporotic bone regeneration, the porous Sr-substituted calcium silicate (SrCS) ceramic scaffolds combining the functions of Sr and Si elements were developed with the goals to promote osteoporotic bone defect repair. The effects of the ionic extract from SrCS on osteogenic differentiation of bone marrow mesenchymal stem cells derived from ovariectomized rats (rBMSCs-OVX), angiogenic differentiation of human umbilical vein endothelial cells (HUVECs) were investigated. The in vitro results showed that Sr and Si ions released from SrCS enhanced cell viability, alkaline phosphatase (ALP) activity, and mRNA expression levels of osteoblast-related genes of rBMSCs-OVX and expression of vascular endothelial growth factor (VEGF) without addition of extra osteogenic and angiogenic reagents. The activation in extracellular signal-related kinases (ERK) and p38 signaling pathways were observed in rBMSCs-OVX cultured in the extract of SrCS, and these effects could be blocked by ERK inhibitor PD98059, and P38 inhibitor SB203580, respectively. Furthermore, the ionic extract of SrCS stimulated HUVECs proliferation, differentiation and angiogenesis process. The in vivo experiments revealed that SrCS dramatically stimulated bone regeneration and angiogenesis in a critical sized OVX calvarial defect model, and the enhanced bone regeneration might be attributed to the modulation of osteogenic differentiation of endogenous mesenchymal stem cells (MSCs) and the inhibition of osteoclastogenesis, accompanying with the promotion of the angiogenic activity of endothelial cells (ECs).
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Maternal separation is associated with DNA methylation and behavioural changes in adult rats.
Eur Neuropsychopharmacol
PUBLISHED: 07-17-2013
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Early life stress is known to promote long-term neurobiological changes, which may underlie the increased risk of psychopathology. Maternal separation (MS) is used as an early life stressor that causes profound neurochemical and behavioural changes in the pups that persist into adulthood. However, the exact mechanism of how MS alters these behavioural changes is not yet understood. Epigenetic modifications, such as DNA methylation, are critical regulators of persistent gene expression changes and may be related to behavioural disorders. The aim of the present study was to investigate whether early life stress on rats could alter cocaine-induced behavioural sensitisation in adulthood via aberrant DNA methylation. We have three main findings: (1) MS increased DNA methyltransferases (DNMTs) expression in the nucleus accumbens (NAc) of infant and adult rats; (2) MS induced DNA hypomethylation on a global level in the NAc, and hypermethylation of the promoter regions of the protein phosphatase 1 catalytic subunit (PP1C) and adenosine A2Areceptor (A2AR) genes, which was associated with their transcriptional downregulation in the NAc; (3) MS-induced molecular changes paralleled an increased response to cocaine-induced locomotor activity and exploratory behaviour in adult rats. Thus, our results suggest that stressful experiences in early life may create a background, via aberrant DNA methylation, which promotes the development of cocaine-induced behavioural sensitisation in adulthood.
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The HIV/AIDS epidemic characteristics in a northeast province of China-Men who have sex with men have made a tremendous contribution to the growth of the HIV epidemic.
J. Infect.
PUBLISHED: 07-14-2013
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To investigate the characteristics and trends of the HIV epidemic in Heilongjiang province of China between 1993 and 2012.
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Superiority of preemptive donor lymphocyte infusion based on minimal residual disease in acute leukemia patients after allogeneic hematopoietic stem cell transplantation.
Transfusion
PUBLISHED: 07-01-2013
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Donor lymphocyte infusion (DLI) was used as salvage therapy in leukemia relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT), but existing results on DLI administration to acute leukemia patients were disappointing. Although increasing minimal residual disease (MRD) after HSCT had been proven to be highly indicative of posttransplant relapse, preemptive DLI (pDLI) based on MRD has not been well evaluated.
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Multilevel Hierarchically Ordered Artificial Biomineral.
Small
PUBLISHED: 05-27-2013
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Living organisms are known for creating complex organic-inorganic hybrid materials such as bone, teeth, and shells, which possess outstanding functions as compared to their simple mineral forms. This has inspired many attempts to mimic such structures, but has yielded few practical advances. In this study, a multilevel hierarchically ordered artificial biomineral (a composite of hydroxyapatite and gelatine) with favorable nanomechanical properties is reported. A typical optimized HAp/gelatin hybrid material in the perpendicular direction of the HAp c-axis has a modulus of 25.91 + 1.78 GPa and hardness of 0.90 + 0.10 GPa, which well matches that of human cortical bone (modulus 24.3 + 1.4 GPa, hardness 0.69 + 0.05 GPa). The bottom-up crystal constructions (from nano- to micro- to macroscale) of this material are achieved through a hard template approach by the phase transformation from DCP to HAp. The structural biomimetic material shows another way to mimic the complex hierarchical designs of sclerous tissues which have potential value for application in hard tissue engineering.
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S-adenosylmethionine modifies cocaine-induced DNA methylation and increases locomotor sensitization in mice.
Int. J. Neuropsychopharmacol.
PUBLISHED: 05-20-2013
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Several studies suggest that individual variability is a critical component underlying drug addiction as not all members of a population who use addictive substance become addicted. There is evidence that the overall epigenetic status of a cell (epigenome) can be modulated by a variety of environmental factors, such as nutrients and chemicals. Based on these data, our aim was to investigate whether environmental factors like S-adenosylmethionine (SAM) via affecting epigenome could alter cocaine-induced gene expression and locomotor sensitization in mice. Our results demonstrate that repeated SAM (10 mm/kg) pretreatment significantly potentiated cocaine-induced locomotor sensitization. Using mouse nucleus accumbens (NAc) tissue, whole-genome gene expression profiling revealed that repeated SAM treatment affected a limited number of genes, but significantly modified cocaine-induced gene expression by blunting non-specifically the cocaine response. At the gene level, we discovered that SAM modulated cocaine-induced DNA methylation by inhibiting both promoter-associated CpG-island hyper- and hypomethylation in the NAc but not in the reference tissue cerebellum. Finally, our in vitro and in vivo data show that the modulating effect of SAM is in part due to decreased methyltransferase activity via down-regulation of Dnmt3a mRNA. Taken together, our results suggest that environmental factors that affect the NAc-cell epigenome may alter the development of psychostimulant-induced addiction and this may explain, at least partly, why some individuals are more vulnerable to drug addiction.
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Fabrication of All-Carbon Nanotube Electronic Devices on Flexible Substrates Through CVD and Transfer Methods.
Adv. Mater. Weinheim
PUBLISHED: 05-18-2013
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SWNT thin films with different nanotube densities are fabricated by CVD while controlling the concentration of catalyst and growth time. Three layers of SWNT films are transferred to flexible substrates serving as electrodes and channel materials, respectively. All-carbon nanotube TFTs with an on/off ratio as high as 10(5) are obtained. Inverters are fabricated on top of the flexible substrates with symmetric input/output behavior.
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Sensitivity limits and scaling of bioelectronic graphene transducers.
Nano Lett.
PUBLISHED: 05-14-2013
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Semiconducting nanomaterials are being intensively studied as active elements in bioelectronic devices, with the aim of improving spatial resolution. Yet, the consequences of size-reduction on fundamental noise limits, or minimum resolvable signals, and their impact on device design considerations have not been defined. Here, we address these key issues by quantifying the size-dependent performance and limiting factors of graphene (Gra) transducers under physiological conditions. We show that suspended Gra devices represent the optimal configuration for cardiac extracellular electrophysiology in terms of both transducer sensitivity, systematically ~5× higher than substrate-supported devices, and forming tight bioelectronic interfaces. Significantly, noise measurements on free-standing Gra together with theoretical calculations yield a direct relationship between low-frequency 1/f noise and water dipole-induced disorders, which sets fundamental sensitivity limits for Gra devices in physiological media. As a consequence, a square-root-of-area scaling of Gra transducer sensitivity was experimentally revealed to provide a critical design rule for their implementation in bioelectronics.
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A two-step stimulus-response cell-SELEX method to generate a DNA aptamer to recognize inflamed human aortic endothelial cells as a potential in vivo molecular probe for atherosclerosis plaque detection.
Anal Bioanal Chem
PUBLISHED: 05-08-2013
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Aptamers are single-stranded oligonucleotides that are capable of binding wide classes of targets with high affinity and specificity. Their unique three-dimensional structures present numerous possibilities for recognizing virtually any class of target molecules, making them a promising alternative to antibodies used as molecular probes in biomedical analysis and clinical diagnosis. In recent years, cell-systematic evolution of ligands by exponential enrichment (SELEX) has been used extensively to select aptamers for various cell targets. However, aptamers that have evolved from cell-SELEX to distinguish the "stimulus-response cell" have not previously been reported. Moreover, a number of cumbersome and time-consuming steps involved in conventional cell-SELEX reduce the efficiency and efficacy of the aptamer selection. Here, we report a "two-step" methodology of cell-SELEX that successfully selected DNA aptamers specifically against "inflamed" endothelial cells. This has been termed as stimulus-response cell-SELEX (SRC-SELEX). The SRC-SELEX enables the selection of aptamers to distinguish the cells activated by stimulus of healthy cells or cells isolated from diseased tissue. We report a promising aptamer, N55, selected by SRC-SELEX, which can bind specifically to inflamed endothelial cells both in cell culture and atherosclerotic plaque tissue. This aptamer probe was demonstrated as a potential molecular probe for magnetic resonance imaging to target inflamed endothelial cells and atherosclerotic plaque detection.
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The stimulation of osteogenic differentiation of mesenchymal stem cells and vascular endothelial growth factor secretion of endothelial cells by ?-CaSiO3 /?-Ca3 (PO4 )2 scaffolds.
J Biomed Mater Res A
PUBLISHED: 04-30-2013
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Porous ?-CaSiO3 /?-Ca3 (PO4 )2 (?-CS/?-TCP) composite scaffolds have been previously shown to promote bone formation in vivo. However, the mechanisms underlying such beneficial effects remain unclear. In this study, we recreated an extracellular environment using the extracts of ?-CS/?-TCP composites developed in our previous in vivo study, and investigated the effects of the extracts on osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells (rBMSCs) and its related mechanisms. The angiogenic potential of the extracts was also evaluated using human umbilical vein endothelial cells (HUVECs). In the absence of osteogenic supplements, the osteogenic differentiation of rBMSCs was detected by alkaline phosphatase (ALP) activity assay and the messenger RNA expression of a panel of osteoblast markers. The results showed that the soluble ions of porous ?-CS/?-TCP composites were capable of promoting cell viability, directly inducing cell differentiation. The increase in phosphorylation of AMP-activated protein kinase (AMPK) and ERK1/2 were observed in rBMSCs cultured in ?-CS/?-TCP composite extracts. The ALP expression, calcium deposition, and ERK1/2 phosphorylation of rBMSCs, which was promoted by ions released from ?-CS/?-TCP composites, were blocked by an AMPK inhibitor, Compound C. These results indicate that bioactive ions extracted from ?-CS/?-TCP composites could stimulate the osteogenic differentiation of rBMSCs via the AMPK-Erk1/2 pathway. Interestingly, the secretion of vascular endothelial growth factor and the viability of HUVECs were shown to be enhanced in the presence of extracts from the ?-CS/?-TCP composite scaffolds. Our findings suggest that 50 or 80% wt. CS could promote bone regeneration by stimulating osteogenesis and angiogenesis. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
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Synthesis of medium chain length fatty acid ethyl esters in engineered Escherichia coli using endogenously produced medium chain fatty acids.
Enzyme Microb. Technol.
PUBLISHED: 03-07-2013
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Microbial biosynthesis of fatty acid-derived biofuels from renewable carbon sources has attracted significant attention in recent years. Free fatty acids (FFAs) can be used as precursors for the production of micro-diesel. The expression of codon optimized two plants (Umbellularia californica and Cinnamomum camphora) medium-chain acyl-acyl carrier protein (ACP) thioesterase genes (ucFatB and ccFatB) in Escherichia coli resulted in a very high level of extractable medium-chain-specific hydrolytic activity and caused large accumulation of medium-chain free fatty acids. By heterologous co-expression of acyl-coenzyme A:diacylglycerol acyltransferase from Acinetobacter baylyi ADP1, specific plant thioesterases in E. coli, with supplementation of exogenous ethanol, resulted in drastic changes in fatty acid ethyl esters (FAEEs) composition ranging from 12:0 to 18:1. Through an optimized microbial shake-flask fermentation of two modified E. coli strains, yielded FFAs and FAEEs in the concentration of approximately 500 mg L(-1)/250 mg L(-1) and 2.01 mg g(-1)/1.99 mg g(-1), respectively. The optimal ethanol level for FAEEs yield in the two recombinant strains was reached at the 3% ethanol concentration, which was about 5.4-fold and 1.93-fold higher than that of 1% ethanol concentration.
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The effect of calcium silicate on in vitro physiochemical properties and in vivo osteogenesis, degradability and bioactivity of porous ?-tricalcium phosphate bioceramics.
Biomed Mater
PUBLISHED: 02-22-2013
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Porous ?-tricalcium phosphate(TCP)/calcium silicate(CS) composite bioceramics with different weight proportions were prepared to investigate the in vitro effects of CS on the physiochemical properties of TCP and the in vivo effects of CS on the degradability, osteogenesis and bioactivity of TCP. The physiochemical results showed that the addition of CS to porous TCP resulted in a looser and rougher surface and a lower solid density, compressive strength and Youngs modulus and a lower pH value as compared to pure CS without any chemical interaction between the TCP and the CS. The in vivo study showed that the material degradation of porous TCP/CS composite bioceramics was slower than that of pure CS, although the osteogenesis, degradability and bioactivity were significantly increased in the long term. Thereafter, the introduction of CS into porous TCP bioceramics is an effective way to prepare bioactive bone grafting scaffolds for clinical use and to control properties such as in vivo degradability and osteoinduction of TCP.
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Antidepressant therapy in patients undergoing coronary artery bypass grafting: the MOTIV-CABG trial.
Ann. Thorac. Surg.
PUBLISHED: 02-17-2013
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The efficacy of antidepressant therapy in patients undergoing coronary artery bypass grafting (CABG) is not clearly established.
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Facile fabrication of nanorod-assembled fluorine-substituted hydroxyapatite (FHA) microspheres.
Chem Asian J
PUBLISHED: 02-12-2013
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Nanorod-assembled FHA microspheres with different F contents were for the first time prepared through a facile one-step hydrothermal method. The effect of the reaction time and pH value of reaction solutions on the FHA morphology was investigated to elucidate the self-assembly process of FHA microspheres. The results showed pH values had significant effect on the morphology of the formed FHA crystals, which were self-assembled into sphere-like sturctures at high pH conditions and rod-like structures at low pH values. The results suggested that formation of FHA crystals with varied morphology may be directly related to Ca(2+) release kinetics from EDTA-Ca-Na2 at different pH conditions. Furthermore, it was found that the chemical stability of FHA microspheres was dependent on the F content in the materials, and high F contents in FHA microspheres lead to improved chemical stability. These results suggest that the prepared self-assembled FHA microspheres may be used for teeth substitution materials due to their unique hierarchical structures and controllable chemical stability.
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