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Find video protocols related to scientific articles indexed in Pubmed.
Alignment and structural control of nitrogen-doped carbon nanotubes by utilizing precursor concentration effect.
Nanotechnology
PUBLISHED: 11-05-2014
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Nitrogen-doped carbon nanotubes (NCNTs) were prepared using a simple ultrasonic spray pyrolysis method. The precursor concentration effect was examined to effectively control alignment, open tip and diameter of the NCNTs by changing xylene/cyclohexylamine ratio. The structure and morphology of the resultant NCNTs were characterized by scanning electron microscopy, transmission electron microscopy and x-ray photoelectron spectroscopy. The degree of alignment and the diameter of the NCNTs increased as the xylene/cyclohexylamine precursor mixture was changed from 0 to 35% cyclohexylamine. This precursor composition also caused a large number of open-ended nanotubes to form with graphite layers inside the cavities of the NCNTs. However, further increase cyclohexylamine content in the precursor reduced the degree of alignment and diameter of the NCNTs. We demonstrate control over the NCNT alignment and diameter, along with the formation of open-ended nanotube tips, and propose a growth mechanism to understand how these properties are interlinked.
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Single molecular spectroscopy: identification of individual fullerene molecules.
Phys. Rev. Lett.
PUBLISHED: 10-29-2014
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We report the molecule-by-molecule spectroscopy of individual fullerenes by means of electron spectroscopy based on scanning transmission electron microscopy. Electron energy-loss fine structure analysis of carbon 1s absorption spectra is used to discriminate carbon allotropes with known symmetries. C_{60} and C_{70} molecules randomly stored inside carbon nanotubes are successfully identified at a single-molecular basis. We show that a single molecule impurity is detectable, allowing the recognition of an unexpected contaminant molecule with a different symmetry. Molecules inside carbon nanotubes thus preserve their intact molecular symmetry. In contrast, molecules anchored at or sandwiched between atomic BN layers show spectral modifications possibly due to a largely degraded structural symmetry. Moreover, by comparing the spectrum from a single C_{60} molecule and its molecular crystal, we find hints of the influence of solid-state effects on its electronic structure.
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Injury-induced MRP8/MRP14 stimulates IP-10/CXCL10 in monocytes/macrophages.
FASEB J.
PUBLISHED: 10-25-2014
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Trauma/hemorrhagic shock is associated with morbidity and mortality due to dysregulated inflammation, which is driven in part by monocytes/macrophages stimulated by injury-induced release of damage-associated molecular pattern (DAMP) molecules. MRP8/MRP14 is an endogenous DAMP involved in various inflammatory diseases, though its mechanism of action is unclear. Circulating MRP8/MRP14 levels in human blunt trauma nonsurvivors were significantly lower than those of survivors (P < 0.001). Human monocytic THP-1 cells stimulated with MRP8/MRP14 expressed the chemokine IFN-? inducible protein 10 (IP-10)/CXCL10. Circulating IP-10 levels in human blunt trauma patients were correlated positively with MRP8/MRP14 levels (r = 0.396, P < 0.001), and were significantly lower in trauma nonsurvivors than in survivors (P < 0.001). We therefore sought to determine the mechanisms by which MRP8/MRP14 stimulates IP-10 in monocytes/macrophages, and found that induction of IP-10 by MRP8/MRP14 required Toll-like receptor 4 and TRIF but not MyD88. Full induction of IP-10 by MRP8/MRP14 required synergy between the transcription factors NF-?B and IFN regulatory factor 3 (IRF3). The receptor for IP-10 is CXCR3, and MRP8/MRP14-induced chemotaxis of CXCR3(+) cells was dependent on the production of IP-10 in monocytes/macrophages. Furthermore, in vivo study with a mouse trauma/hemorrhagic shock model showed that administration of neutralizing antibody against MRP8 prevented activation of NF-?B and IRF3 as well as IP-10 production. Thus, the current study identified a novel signaling mechanism that controls IP-10 expression in monocytes/macrophages by MRP8/MRP14, which may play an important role in injury-induced inflammation.-Wang, J., Vodovotz, Y., Fan, L., Li, Y., Liu, Z., Namas, R., Barclay, D., Zamora, R., Billiar, T. R., Wilson, M. A., Fan, J., Jiang, Y. Injury-induced MRP8/MRP14 stimulates IP-10/CXCL10 in monocytes/macrophages.
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[Clinical analysis and literature review of primary melanoma in nasal cavity and sinus--report of 9 cases].
Lin Chung Er Bi Yan Hou Tou Jing Wai Ke Za Zhi
PUBLISHED: 10-18-2014
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To analyze and summarize clinical characteristic, treatment scheme and survival rate of primary melanom in nasal cavity and sinus.
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Clinical value of serum HMGB1 in diagnosis and prognosis of laryngeal squamous cell carcinoma.
Med. Oncol.
PUBLISHED: 10-14-2014
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Laryngeal squamous cell carcinoma (LSCC) is one of the most common malignancies in the head and neck region. Recently, aberrantly expressed high-mobility group box 1 (HMGB1) has received a great deal of attention as a potential biomarker for cancer diagnosis and prognosis. Therefore, the aim of this study was to estimate HMGB1 levels in serum in LSCC patients and healthy controls and evaluated the potential of serum HMGB1 as a noninvasive biomarker for diagnosis and prognosis in LSCC. Serum HMGB1 levels were analyzed in 71 LSCC patients and 50 healthy controls. The serum HMGB1 level was significantly higher in LSCC patients compared with the healthy controls (4.81 ± 2.33 vs. 3.21 ± 1.08 ng/mL, P < 0.001). High serum HMGB1 was significantly associated with T classification (P = 0.005), N classification (P = 0.002), and clinical stage (P = 0.001). The area under ROC curve was 0.716, and the sensitivity and specificity were 42.3 and 92.0 %, respectively. The Kaplan-Meier plots showed that patients with high serum HMGB1 had a poorer overall survival than those with low serum HMGB1 (P = 0.036). Serum HMGB1 levels are significantly associated with the progression of LSCC. In this population, HMGB1 has a poor sensitivity, but a high specificity for the diagnosis of LSCC. Serum HMGB1 level has potential as a biomarker for the prognosis in LSCC patients.
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Capsid expansion mechanism of bacteriophage T7 revealed by multistate atomic models derived from cryo-EM reconstructions.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 10-13-2014
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Many dsDNA viruses first assemble a DNA-free procapsid, using a scaffolding protein-dependent process. The procapsid, then, undergoes dramatic conformational maturation while packaging DNA. For bacteriophage T7 we report the following four single-particle cryo-EM 3D reconstructions and the derived atomic models: procapsid (4.6-Å resolution), an early-stage DNA packaging intermediate (3.5 Å), a later-stage packaging intermediate (6.6 Å), and the final infectious phage (3.6 Å). In the procapsid, the N terminus of the major capsid protein, gp10, has a six-turn helix at the inner surface of the shell, where each skewed hexamer of gp10 interacts with two scaffolding proteins. With the exit of scaffolding proteins during maturation the gp10 N-terminal helix unfolds and swings through the capsid shell to the outer surface. The refolded N-terminal region has a hairpin that forms a novel noncovalent, joint-like, intercapsomeric interaction with a pocket formed during shell expansion. These large conformational changes also result in a new noncovalent, intracapsomeric topological linking. Both interactions further stabilize the capsids by interlocking all pentameric and hexameric capsomeres in both DNA packaging intermediate and phage. Although the final phage shell has nearly identical structure to the shell of the DNA-free intermediate, surprisingly we found that the icosahedral faces of the phage are slightly (?4 Å) contracted relative to the faces of the intermediate, despite the internal pressure from the densely packaged DNA genome. These structures provide a basis for understanding the capsid maturation process during DNA packaging that is essential for large numbers of dsDNA viruses.
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Sulfur-doped porous reduced graphene oxide hollow nanosphere frameworks as metal-free electrocatalysts for oxygen reduction reaction and as supercapacitor electrode materials.
Nanoscale
PUBLISHED: 10-07-2014
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Chemical doping with foreign atoms is an effective approach to significantly enhance the electrochemical performance of the carbon materials. Herein, sulfur-doped three-dimensional (3D) porous reduced graphene oxide (RGO) hollow nanosphere frameworks (S-PGHS) are fabricated by directly annealing graphene oxide (GO)-encapsulated amino-modified SiO2 nanoparticles with dibenzyl disulfide (DBDS), followed by hydrofluoric acid etching. The XPS and Raman spectra confirmed that sulfur atoms were successfully introduced into the PGHS framework via covalent bonds. The as-prepared S-PGHS has been demonstrated to be an efficient metal-free electrocatalyst for oxygen reduction reaction (ORR) with the activity comparable to that of commercial Pt/C (40%) and much better methanol tolerance and durability, and to be a supercapacitor electrode material with a high specific capacitance of 343 F g(-1), good rate capability and excellent cycling stability in aqueous electrolytes. The impressive performance for ORR and supercapacitors is believed to be due to the synergistic effect caused by sulfur-doping enhancing the electrochemical activity and 3D porous hollow nanosphere framework structures facilitating ion diffusion and electronic transfer.
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Ileocolonic anastomosis after right hemicolectomy for colon cancer: functional end-to-end or end-to-side?
World J Surg Oncol
PUBLISHED: 10-01-2014
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The purpose of this study was to compare short-term clinical outcomes of ileocolonic functional end-to-end anastomosis (FEEA) and end-to-side anastomosis (ESA) following resection of the right colon for cancer.
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Nanoparticle tension probes patterned at the nanoscale: impact of integrin clustering on force transmission.
Nano Lett.
PUBLISHED: 09-30-2014
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Herein we aimed to understand how nanoscale clustering of RGD ligands alters the mechano-regulation of their integrin receptors. We combined molecular tension fluorescence microscopy with block copolymer micelle nanolithography to fabricate substrates with arrays of precisely spaced probes that can generate a 10-fold fluorescence response to pN-forces. We found that the mechanism of sensing ligand spacing is force-mediated. This strategy is broadly applicable to investigating receptor clustering and its role in mechanotransduction pathways.
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Tumor miR-125b predicts recurrence and survival of patients with clear-cell renal cell carcinoma after surgical resection.
Cancer Sci.
PUBLISHED: 09-23-2014
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The present study aims to evaluate the impact of tumor microRNA-125b (miR-125b) on recurrence and survival of patients with clear-cell renal cell carcinoma (ccRCC) following surgery. We retrospectively enrolled 276 patients (200 in the training cohort and 76 in the validation cohort) with ccRCC undergoing nephrectomy at a single institution. Clinicopathologic features, cancer-specific survival (CSS) and recurrence-free survival (RFS) were recorded. Tumor miR-125b levels were assessed by in situ hybridization (ISH) in specimens of patients. The Kaplan-Meier method was applied to compare survival curves. Cox regression models were used to analyze the impact of prognostic factors on CSS and RFS. A concordance index (C-index) was calculated to assess predictive accuracy. In both cohorts, tumor miR-125b positively correlated with Fuhrman grade. High tumor miR-125b indicated poor survival and early recurrence for patients with ccRCC, especially with advanced stage disease. After multivariable adjustment, tumor miR-125b was identified as an independent adverse prognostic factor for survival and recurrence. The predictive accuracy of traditional TNM and UCLA Integrated Staging System prognostic models was improved when tumor miR-125b was added. The results showed that tumor miR-125b is a potential independent adverse prognostic biomarker for recurrence and survival of patients with ccRCC after nephrectomy.
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Epitaxial growth of large-gap quantum spin Hall insulator on semiconductor surface.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 09-22-2014
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Formation of topological quantum phase on a conventional semiconductor surface is of both scientific and technological interest. Here, we demonstrate epitaxial growth of 2D topological insulator, i.e., quantum spin Hall state, on Si(111) surface with a large energy gap, based on first-principles calculations. We show that the Si(111) surface functionalized with one-third monolayer of halogen atoms [Si(111)-[Formula: see text]×[Formula: see text]-X (X = Cl, Br, I)] exhibiting a trigonal superstructure provides an ideal template for epitaxial growth of heavy metals, such as Bi, which self-assemble into a hexagonal lattice with high kinetic and thermodynamic stability. Most remarkably, the Bi overlayer is atomically bonded to but electronically decoupled from the underlying Si substrate, exhibiting isolated quantum spin Hall state with an energy gap as large as ?0.8 eV. This surprising phenomenon originates from an intriguing substrate-orbital-filtering effect, which critically selects the orbital composition around the Fermi level, leading to different topological phases. In particular, the substrate-orbital-filtering effect converts the otherwise topologically trivial freestanding Bi lattice into a nontrivial phase; and the reverse is true for Au lattice. The underlying physical mechanism is generally applicable, opening a new and exciting avenue for exploration of large-gap topological surface/interface states.
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Two-dimensional heterostructures: fabrication, characterization, and application.
Nanoscale
PUBLISHED: 09-16-2014
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Two-dimensional (2D) materials such as graphene, hexagonal boron nitrides (hBN), and transition metal dichalcogenides (TMDs, e.g., MoS2) have attracted considerable attention in the past few years because of their novel properties and versatile potential applications. These 2D layers can be integrated into a monolayer (lateral 2D heterostructure) or a multilayer stack (vertical 2D heterostructure). The resulting artificial 2D structures provide access to new properties and applications beyond their component 2D atomic crystals and hence, they are emerging as a new exciting field of research. In this article, we review recent progress on the fabrication, characterization, and applications of various 2D heterostructures.
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One-pot synthesis of protein-embedded metal-organic frameworks with enhanced biological activities.
Nano Lett.
PUBLISHED: 09-15-2014
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Protein molecules were directly embedded in metal-organic frameworks (MOFs) by a coprecipitation method. The protein molecules majorly embedded on the surface region of MOFs display high biological activities. As a demonstration of the power of such materials, the resulting Cyt c embedded in ZIF-8 showed a 10-fold increase in peroxidase activity compared to free Cyt c in solution and thus gave convenient, fast, and highly sensitive detection of trace amounts of explosive organic peroxides in solution.
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Ink-jet printing an optimal multi-enzyme system.
Chem. Commun. (Camb.)
PUBLISHED: 09-13-2014
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A method using ink-jet printing for constructing multi-enzyme systems was proposed, in which a precisely defined enzyme ratio and two-dimensional distribution was obtained by the preset 'color' values. The applications of the print-on-paper multi-enzyme systems were exemplified by the detection of glucose and the design of an enzyme-enabled two-dimensional code.
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[Research of influence factors on spectral recognition for cotton leaf infected by Verticillium wilt].
Guang Pu Xue Yu Guang Pu Fen Xi
PUBLISHED: 09-12-2014
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Through carrying out spectral test experiment, the influence factors of spectrum test were analyzed, the influence degree of various factors in spectral recognition was explicated and the method of spectra test was optimized for cotton leaf infected by verticillium wilt. The results indicated that under different severity levels, the shape and value of reflectance of disease symptoms part were Significantly higher than healthy part on cotton leaf, compared with the black board as baseboard, the spectral values of disease leaves were slightly higher in visible light wavebands and significantly higher in others wavebands than healthy leaves on white baseboard. Different position of leaf on cotton plant has different effect degree to the recognition of disease, the effect of stem leaf was more obvious than that of else leaf, the identical leaf position was less influenced by disease than band. Test time and cotton varieties had less influence on recognizing disease by spectra, and the effect of the same condition was acceptable. Test site had no effect on disease recognition by spectra. The effect of each factor was different for recognizing disease leaf by spectra, and this study will provide reference for the researchers of crop disease diagnosis by spectra.
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[Transplanted epidermal neural crest stem cell in a peripheral nerve gap].
Sheng Wu Gong Cheng Xue Bao
PUBLISHED: 09-09-2014
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Neural crest stem cells originated from hair follicle (epidermal neural crest stem cell, EPI-NCSC) are easy to obtain and have potentials to differentiate into various tissues, which make them eminent seed cells for tissue engineering. EPI-NCSC is now used to repair nerve injury, especially, the spinal cord injury. To investigate their effects on repairing peripheral nerve injury, EPI-NCSC from a GFP-SD rat were primarily cultured on coated dishes and on a poly lactic acid coglycolic acid copolymer (PLGA) membrane. Methyl thiazolyl tetrazolium (MTT) assay showed that the initial adhesion rate of EPI-NCSC was 89.7% on PLGA membrane, and the relative growth rates were 89.3%, 87.6%, 85.6%, and 96.6% on the 1st, 3rd, 5th, 7th day respectively. Cell cycles and DNA ploidy analysis demonstrated that cell cycles and proliferation indexes of cultured EPI-NCSC had the same variation pattern on coated dishes and PLGA membrane. Then cultured EPI-NCSC were mixed with equal amount of extracellular matrix and injected into a PLGA conduit to connect a 10 mm surgery excision gap of rat sciatic nerve, Dulbecco's Modified Eagle's medium (DMEM) was used to substitute EPI-NCSC in the control group. After four weeks of transplantation, the defected sciatic nerve achieved a histological restoration, the sensory function of rat hind limb was partly recovered and the sciatic nerve index was also improved. The above results showed that a PLGA conduit filled with EPI-NCSC has a good repair effect on the peripheral nerve injury.
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Spatial co-localization of multi-enzymes by inorganic nanocrystal-protein complexes.
Chem. Commun. (Camb.)
PUBLISHED: 09-06-2014
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We report a simple precipitation method for the construction of spatially co-localized multi-enzyme systems based on inorganic nanocrystal-protein complexes. A spatially controlled multi-enzyme system exhibits enhanced overall catalytic performance, allowing for sensitive detection of glucose in solution.
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[The expression of VEGF and the regulation of clarithromycin on it in chronic rhinosinusitis with nasal polys].
Lin Chung Er Bi Yan Hou Tou Jing Wai Ke Za Zhi
PUBLISHED: 09-05-2014
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To investigate the expression of vascular endothelial growth factor in the nasal mucosa of chronic rhinosinusitis with nasal polys patients, and explored the regulation of clarithromycin on VEGF.
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Fecal microbiota transplantation through mid-gut for refractory Crohn's disease: Safety, feasibility and efficacy trial results.
J. Gastroenterol. Hepatol.
PUBLISHED: 08-28-2014
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The gut microbiota plays a pivotal role in the intestinal diseases. Fecal microbiota transplantation (FMT) might be a rescue therapy for refractory inflammatory bowel disease. This study aimed to evaluate the safety, feasibility and efficacy of FMT through mid-gut for refractory Crohn's disease (CD).
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Enzymatic oxidation of cholesterol: properties and functional effects of cholestenone in cell membranes.
PLoS ONE
PUBLISHED: 08-26-2014
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Bacterial cholesterol oxidase is commonly used as an experimental tool to reduce cellular cholesterol content. That the treatment also generates the poorly degradable metabolite 4-cholesten-3-one (cholestenone) has received less attention. Here, we investigated the membrane partitioning of cholestenone using simulations and cell biological experiments and assessed the functional effects of cholestenone in human cells. Atomistic simulations predicted that cholestenone reduces membrane order, undergoes faster flip-flop and desorbs more readily from membranes than cholesterol. In primary human fibroblasts, cholestenone was released from membranes to physiological extracellular acceptors more avidly than cholesterol, but without acceptors it remained in cells over a day. To address the functional effects of cholestenone, we studied fibroblast migration during wound healing. When cells were either cholesterol oxidase treated or part of cellular cholesterol was exchanged for cholestenone with cyclodextrin, cell migration during 22 h was markedly inhibited. Instead, when a similar fraction of cholesterol was removed using cyclodextrin, cells replenished their cholesterol content in 3 h and migrated similarly to control cells. Thus, cholesterol oxidation produces long-term functional effects in cells and these are in part due to the generated membrane active cholestenone.
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Synthesis of cholesterol analogues bearing BODIPY fluorophores by Suzuki or Liebeskind-Srogl cross-coupling and evaluation of their potential for visualization of cholesterol pools.
Chembiochem
PUBLISHED: 08-22-2014
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We report a synthetic route to BODIPY-cholesterol conjugates in which the key steps were Suzuki or Liebeskind-Srogl cross-coupling of cholesterol phenyl moieties with structurally diverse BODIPY scaffolds. All conjugates feature single-bonded and hydrophobic linkages between the fluorophore and sterol that are devoid of heteroatoms. Using HeLa cells, we show that these BODIPY-cholesterol analogues can be used simultaneously with the parent BODIPY-cholesterol for cell imaging and flow cytometry. The BODIPY-cholesterol analogues exhibit similar cellular localization in HeLa cells and show similar cholesterol efflux properties from THP-1 cells to HDL acceptors. These results demonstrate that the red-shifted BODIPY-cholesterol analogues behave in a manner similar to unlabeled cholesterol and are useful probes for simultaneous visualization of intracellular cholesterol pools and for monitoring cholesterol efflux from cells to extracellular acceptors.
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Predictors of catheter-related bladder discomfort after urological surgery.
J. Huazhong Univ. Sci. Technol. Med. Sci.
PUBLISHED: 08-19-2014
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The aim of this study was to figure out the predictors of early postoperative catheter-related bladder discomfort (CRBD) after urological surgery. We designed a prospective observational study in our hospital. Consecutive adult patients undergoing surgery under general anaesthesia or epidural anaesthesia necessitating urinary catheterization were included during a 3-month period. severity of bladder discomfort was assessed on a 4-point scale: (1) no pain, (2) mild pain (revealed only by interviewing the patient), (3) moderate (a spontaneous complaint by the patient of a burning sensation in the urethra and/or an urge to urinate and/or sensation of urethral foreign body without any emotional agitation) and (4) severe discomfort (agitation, loud complaints and attempt to remove the bladder catheter associated with a burning sensation in the urethra). Predictors of CRBD were identified by univariate and multivariate analysis. Totally, 116 patients were included, of which 84.5% had CRBD (mild CRBD: 40.5%; moderate or severe CRBD: 44.0%) at day 1, while 31.9% developed CRBD (mild CRBD: 29.3%; moderate or severe CRBD: 2.6%) at day 3. We evaluated 9 potential forecast factors of CRBD, and univariate Chi-square test showed male gender [OR=2.4, 95%CI (1.1-5.6), P<0.05], abdominal open surgery compared with transurethral surgery [OR=0.3, 95%CI (0.1-0.6), P<0.05], abdominal surgery compared with laparoscopic surgery [OR=3.3, 95%CI (1.2-8.9), P<0.05] and history of catheterization [OR=0.5, 95%CI (0.2-0.9), P<0.05] were independent predictors of moderate or severe CRBD in the patients after surgery. While multivariate logistic regression analysis showed that the abdominal open surgery [EXP(B)=3.074, 95%CI (1.3-7.4), P<0.05] and the history of catheterization [EXP(B)=2.458, 95%CI (1.1-5.9), P<0.05] might contribute more to the occurrence of moderate or severe CRBD. In conclusion, this observational study identified that the type of surgery and the history of catheterization might be predictive factors of moderate and severe CRBD after urological surgery.
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Band gap engineering and layer-by-layer mapping of selenium-doped molybdenum disulfide.
Nano Lett.
PUBLISHED: 08-16-2014
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Ternary two-dimensional dichalcogenide alloys exhibit compositionally modulated electronic structure, and hence, control of dopant concentration within each individual layer of these compounds provides a powerful tool to efficiently modify their physical and chemical properties. The main challenge arises when quantifying and locating the dopant atoms within each layer in order to better understand and fine-tune the desired properties. Here we report the synthesis of molybdenum disulfide substitutionally doped with a broad range of selenium concentrations, resulting in over 10% optical band gap modulations in atomic layers. Chemical analysis using Z-contrast imaging provides direct maps of the dopant atom distribution in individual MoS2 layers and hence a measure of the local optical band gaps. Furthermore, in a bilayer structure, the dopant distribution is imaged layer-by-layer. This work demonstrates that each layer in the bilayer system contains similar local Se concentrations, randomly distributed, providing new insights into the growth mechanism and alloying behavior in two-dimensional dichalcogenide atomic layers. The results show that growth of uniform, ternary, two-dimensional dichalcogenide alloy films with tunable electronic properties is feasible.
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Inducible and constitutive expression of an elicitor gene Hrip1 from Alternaria tenuissima enhances stress tolerance in Arabidopsis.
Transgenic Res.
PUBLISHED: 08-14-2014
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Hrip1 is a novel hypersensitive response-inducing protein secreted by Alternaria tenuissima that activates defense responses and systemic acquired resistance in tobacco. This study investigates the role that Hrip1 plays in responses to abiotic and biotic stress using transgenic Arabidopsis thaliana expressing the Hrip1 gene under the control of the stress-inducible rd29A promoter or constitutive cauliflower mosaic virus 35S promoter. Bioassays showed that inducible Hrip1 expression in rd29A?Hrip1 transgenic lines had a significantly higher effect on plant height, silique length, plant dry weight, seed germination and root length under salt and drought stress compared to expression in 35S?Hrip1 lines and wild type plants. The level of enhancement of resistance to Botrytis cinerea by the 35S?Hrip1 lines was higher than in the rd29A?Hrip1 lines. Moreover, stress-related gene expression in the transgenic Arabidopsis lines was significantly increased by 200 mM NaCl and 200 mM mannitol treatments, and defense genes in the jasmonic acid and ethylene signaling pathway were significantly up-regulated after Botrytis inoculation in the Hrip1 transgenic plants. Furthermore, the activity of some antioxidant enzymes, such as peroxidase and catalase increased after salt and drought stress and Botrytis infection. These results suggested that the Hrip1 protein contributes to abiotic and biotic resistance in transgenic Arabidopsis and may be used as a useful gene for resistance breeding in crops. Although the constitutive expression of Hrip1 is suitable for biotic resistance, inducible Hrip1 expression is more responsive for abiotic resistance.
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Disease-specific T-helper cell polarizing function of lesional dendritic cells in different types of chronic rhinosinusitis with nasal polyps.
Am. J. Respir. Crit. Care Med.
PUBLISHED: 08-14-2014
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Although eosinophilic and noneosinophilic chronic rhinosinusitis with nasal polyps (CRSwNP) exhibit distinct T-helper (Th) responses, the underlying mechanisms remain unclear.
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Electrokinetic desalination using honeycomb carbon nanotubes (HC-CNTs): a conceptual study by molecular simulation.
Phys Chem Chem Phys
PUBLISHED: 08-06-2014
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A new concept of electrokinetic desalination using a CNT honeycomb is presented through molecular dynamics simulation. The preferential translocation of ions towards the outlets near two electrodes was realized by applying an electric field perpendicular to bulk fluid flow in a CNT network, which, in the meantime, generated deionized water flux discharged from the central outlets. The effects of the major factors such as electric field strength, numbers of separation units, diameter of CNT, and ion concentration on the desalination were examined. It was shown that over 95% salt rejection and around 50% fresh water recovery were achieved by the presented module by applying an electric field of 0.8 V nm(-1). CNT diameter, which is critical to ion rejection without the electric field, had a marginal effect on the desalination of this new module when a strong electric field was applied. The desalination was also not sensitive to ion concentration, indicating its excellent workability for a wide range of water salinity, e.g. from brackish water to seawater. A potential of mean force profile revealed a free energy barrier as large as 2.0-6.0 kcal mol(-1) for ions to move opposite to the implemented electrical force. The simulation confirmed the high potential of the CNT honeycomb in water desalination.
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Th17 response and its regulation in inflammatory upper airway diseases.
Clin. Exp. Allergy
PUBLISHED: 07-23-2014
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Allergic rhinitis (AR) and chronic rhinosinusitis (CRS) are two widely prevalent inflammatory diseases in the upper airways. T-cell immunity has been suggested to play an important pathogenic role in many chronic inflammatory diseases including inflammatory upper airway diseases. Inappropriate CD4(+) T cell responses, especially the dysregulation of the Th1/Th2 balance leading to excessive Th1 or Th2 cell activation, have been associated with allergic rhinitis and chronic rhinosinusitis. Nevertheless, recent studies suggest that IL-17A and IL-17A-producing Th17 cell subset, a distinct pro-inflammatory CD4(?) T cell lineage, may also play an important role in the pathophysiology of inflammatory upper airway diseases. Th17 cells may promote both eosinophilic and neutrophilic inflammation in AR and CRS. In addition, a few, but accumulating evidence shows that the Th17 responses can be tightly regulated by endogenous and exogenous substances in the context of AR and CRS. This review discusses recent advances in our understanding of the expression and function of the Th17 response and its regulation in inflammatory upper airway diseases, and the perspective for future investigation and clinical utility. This article is protected by copyright. All rights reserved.
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Electrical transport properties of polycrystalline monolayer molybdenum disulfide.
ACS Nano
PUBLISHED: 07-23-2014
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Semiconducting MoS2 monolayers have shown many promising electrical properties, and the inevitable polycrystallinity in synthetic, large-area films renders understanding the effect of structural defects, such as grain boundaries (GBs, or line-defects in two-dimensional materials), essential. In this work, we first examine the role of GBs in the electrical-transport properties of MoS2 monolayers with varying line-defect densities. We reveal a systematic degradation of electrical characteristics as the line-defect density increases. The two common MoS2 GB types and their specific roles are further examined, and we find that only tilt GBs have a considerable effect on the MoS2 electrical properties. By examining the electronic states and sources of disorder using temperature-dependent transport studies, we adopt the Anderson model for disordered systems to explain the observed transport behaviors in different temperature regimes. Our results elucidate the roles played by GBs in different scenarios and give insights into their underlying scattering mechanisms.
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Crystal structure of DnaT84-153-dT10 ssDNA complex reveals a novel single-stranded DNA binding mode.
Nucleic Acids Res.
PUBLISHED: 07-22-2014
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DnaT is a primosomal protein that is required for the stalled replication fork restart in Escherichia coli. As an adapter, DnaT mediates the PriA-PriB-ssDNA ternary complex and the DnaB/C complex. However, the fundamental function of DnaT during PriA-dependent primosome assembly is still a black box. Here, we report the 2.83 Å DnaT(84-153)-dT10 ssDNA complex structure, which reveals a novel three-helix bundle single-stranded DNA binding mode. Based on binding assays and negative-staining electron microscopy results, we found that DnaT can bind to phiX 174 ssDNA to form nucleoprotein filaments for the first time, which indicates that DnaT might function as a scaffold protein during the PriA-dependent primosome assembly. In combination with biochemical analysis, we propose a cooperative mechanism for the binding of DnaT to ssDNA and a possible model for the assembly of PriA-PriB-ssDNA-DnaT complex that sheds light on the function of DnaT during the primosome assembly and stalled replication fork restart. This report presents the first structure of the DnaT C-terminal complex with ssDNA and a novel model that explains the interactions between the three-helix bundle and ssDNA.
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Impact of microbubble enhanced, pulsed, focused ultrasound on tumor circulation of subcutaneous VX2 cancer.
Chin. Med. J.
PUBLISHED: 07-22-2014
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Intravascular microbubble-enhanced acoustic cavitation is capable of disrupting the vascular walls of capillaries and small vessels. This study was designed to investigate the impact of microbubble-enhanced, pulsed and focused ultrasound (MEUS) on the blood perfusion of subcutaneous VX2 tumors in rabbits.
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Gating electron-hole asymmetry in twisted bilayer graphene.
ACS Nano
PUBLISHED: 07-10-2014
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Electron-hole symmetry is one of the unique properties of graphene that is generally absent in most semiconductors because of the different conduction and valence band structures. Here we report on the manipulation of electron-hole symmetry in the low-energy band structure of twisted bilayer graphene, where symmetric saddle points form in the conduction and valence bands as a result of interlayer coupling. By applying a gate voltage to a twisted bilayer with a critical rotation angle, enhanced electron resonance between the two saddle points can be turned on or off, depending on the electron-hole symmetry near the saddle points. The appearance of a 2D(+) peak, a gate-tunable Raman feature found near the critical angle, indicates a reduction of Fermi velocity in the vicinity of the saddle point to/from which electrons are inelastically scattered by phonons in the round trip of the double-resonance process.
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[Effect of transanal excision in the treatment of rectal cancer].
Zhonghua Wei Chang Wai Ke Za Zhi
PUBLISHED: 06-24-2014
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The surgical approach for rectal cancer includes trans-abdominal and transanal excision. Total mesorectal excision(TME) is the golden standard for surgical treatment. In the functional surgery era, more and more evidence shows that under strict indications, traditional abdominal radical surgery and transanal excision can achieve similar survival in patients with early stage cancer. However, the local recurrence rate of local resection was significantly higher compared to TME, suggesting strict patients selection for transanal excision. Preoperative accurate evaluation is critical in clinical practice.
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ATRA-induced cellular differentiation and CD38 expression inhibits acquisition of BCR-ABL mutations for CML acquired resistance.
PLoS Genet.
PUBLISHED: 06-01-2014
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Acquired resistance through genetic mutations is a major obstacle in targeted cancer therapy, but the underlying mechanisms are poorly understood. Here we studied mechanisms of acquired resistance of chronic myeloid leukemia (CML) to tyrosine kinase inhibitors (TKIs) by examining genome-wide gene expression changes in KCL-22 CML cells versus their resistant KCL-22M cells that acquire T315I BCR-ABL mutation following TKI exposure. Although T315I BCR-ABL is sufficient to confer resistance to TKIs in CML cells, surprisingly we found that multiple drug resistance pathways were activated in KCL-22M cells along with reduced expression of a set of myeloid differentiation genes. Forced myeloid differentiation by all-trans-retinoic acid (ATRA) effectively blocked acquisition of BCR-ABL mutations and resistance to the TKIs imatinib, nilotinib or dasatinib in our previously described in vitro models of acquired TKI resistance. ATRA induced robust expression of CD38, a cell surface marker and cellular NADase. High levels of CD38 reduced intracellular nicotinamide adenine dinucleotide (NAD+) levels and blocked acquired resistance by inhibiting the activity of the NAD+-dependent SIRT1 deacetylase that we have previously shown to promote resistance in CML cells by facilitating error-prone DNA damage repair. Consequently, ATRA treatment decreased DNA damage repair and suppressed acquisition of BCR-ABL mutations. This study sheds novel insight into mechanisms underlying acquired resistance in CML, and suggests potential benefit of combining ATRA with TKIs in treating CML, particularly in advanced phases.
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A new diketopyrrolopyrrole-based probe for sensitive and selective detection of sulfite in aqueous solution.
Spectrochim Acta A Mol Biomol Spectrosc
PUBLISHED: 05-21-2014
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A new probe was synthesized by incorporating an ?,? -unsaturated ketone to a diketopyrrolopyrrole fluorophore. The probe had exhibited a selective and sensitive response to the sulfite against other thirteen anions and biothiols (Cys, Hcy and GSH), through the nucleophilic addition of sulfite to the alkene of probe with the detection limit of 0.1?M in HEPES (10mM, pH 7.4) THF/H2O (1:1, v/v). Meanwhile, it could be easily observed that the probe for sulfite changed from pink to colorless by the naked eye, and from pink to blue under UV lamp after the sulfite was added for 20min. The NMR and Mass spectral analysis demonstrated the expected addition of sulfite to the CC bonds.
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Formation of quantum spin Hall state on Si surface and energy gap scaling with strength of spin orbit coupling.
Sci Rep
PUBLISHED: 05-07-2014
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For potential applications in spintronics and quantum computing, it is desirable to place a quantum spin Hall insulator [i.e., a 2D topological insulator (TI)] on a substrate while maintaining a large energy gap. Here, we demonstrate a unique approach to create the large-gap 2D TI state on a semiconductor surface, based on first-principles calculations and effective Hamiltonian analysis. We show that when heavy elements with strong spin orbit coupling (SOC) such as Bi and Pb atoms are deposited on a patterned H-Si(111) surface into a hexagonal lattice, they exhibit a 2D TI state with a large energy gap of ?0.5?eV. The TI state arises from an intriguing substrate orbital filtering effect that selects a suitable orbital composition around the Fermi level, so that the system can be matched onto a four-band effective model Hamiltonian. Furthermore, it is found that within this model, the SOC gap does not increase monotonically with the increasing strength of SOC. These interesting results may shed new light in future design and fabrication of large-gap topological quantum states.
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Vertical and in-plane heterostructures from WS2/MoS2 monolayers.
Nat Mater
PUBLISHED: 04-25-2014
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Layer-by-layer stacking or lateral interfacing of atomic monolayers has opened up unprecedented opportunities to engineer two-dimensional heteromaterials. Fabrication of such artificial heterostructures with atomically clean and sharp interfaces, however, is challenging. Here, we report a one-step growth strategy for the creation of high-quality vertically stacked as well as in-plane interconnected heterostructures of WS2/MoS2 via control of the growth temperature. Vertically stacked bilayers with WS2 epitaxially grown on top of the MoS2 monolayer are formed with preferred stacking order at high temperature. A strong interlayer excitonic transition is observed due to the type II band alignment and to the clean interface of these bilayers. Vapour growth at low temperature, on the other hand, leads to lateral epitaxy of WS2 on MoS2 edges, creating seamless and atomically sharp in-plane heterostructures that generate strong localized photoluminescence enhancement and intrinsic p-n junctions. The fabrication of heterostructures from monolayers, using simple and scalable growth, paves the way for the creation of unprecedented two-dimensional materials with exciting properties.
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Atomic structure and dynamic behaviour of truly one-dimensional ionic chains inside carbon nanotubes.
Nat Mater
PUBLISHED: 04-24-2014
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Materials with reduced dimensionality have attracted much interest in various fields of fundamental and applied science. True one-dimensional (1D) crystals with single-atom thickness have been realized only for few elemental metals (Au, Ag) or carbon, all of which showed very short lifetimes under ambient conditions. We demonstrate here a successful synthesis of stable 1D ionic crystals in which two chemical elements, one being a cation and the other an anion, align alternately inside carbon nanotubes. Unusual dynamical behaviours for different atoms in the 1D lattice are experimentally corroborated and suggest substantial interactions of the atoms with the nanotube sheath. Our theoretical studies indicate that the 1D ionic crystals have optical properties distinct from those of their bulk counterparts and that the properties can be engineered by introducing atomic defects into the chains.
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Plasmonic hot electron induced structural phase transition in a MoS2 monolayer.
Adv. Mater. Weinheim
PUBLISHED: 04-21-2014
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A reversible 2H-to-1T phase transition in a MoS2 monolayer is realized by plasmonic hot electrons. This transition can be actively controlled by the incident light intensity, wavelength, sample areas, and perimeters, resulting in an effective shift of photoluminescence. The suggested configuration paves the way for plasmonic optoelectronic device applications of MoS2 in the future.
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Synergic Effects of EPI-NCSCs and OECs on the Donor Cells Migration, the Expression of Neurotrophic Factors, and Locomotor Recovery of Contused Spinal Cord of Rats.
J. Mol. Neurosci.
PUBLISHED: 04-14-2014
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Cell-based therapy is a promising strategy for the repair of spinal cord injury (SCI), and the synergic effects of donor cells are emphasized in recent years. In this study, epidermal neural crest stem cells (EPI-NCSCs) and olfactory ensheathing cells (OECs) were transplanted into the contused spinal cord of rats separately or jointly at 1 week after injury. At 3 and 9 weeks posttransplantation, migration of the donor cells, expression of brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) and functional recovery of the contused cord were determined by techniques of histopathology, quantitative real-time polymerase chain reaction (qPCR), immunohistochemistry and Basso-Beattie-Bresnahan (BBB) score. The results showed that the migration and distribution of EPI-NCSCs in vivo were promoted by OECs at 3 weeks after transplantation, but they vanished at 9 weeks. The expression of BDNF and GDNF was significantly increased by co-transplantation at molecular and protein level. Although the expression of both factors in EPI-NCSCs- and OECs-injected group was lower than in co-injected group, it was higher than in control groups. Similarly, the best locomotor recovery of the contused cord was acquired from co-injected animals. As we know, this is the first time to study the synergic effects of EPI-NCSCs and OECs, and the data indicates that donor cells migration, expression of neurotrophic factors (NTFs), and recovery of motor function can be improved by EPI-NCSCs and OECs synergistically.
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Identification of 'erasers' for lysine crotonylated histone marks using a chemical proteomics approach.
Elife
PUBLISHED: 04-03-2014
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Posttranslational modifications (PTMs) play a crucial role in a wide range of biological processes. Lysine crotonylation (Kcr) is a newly discovered histone PTM that is enriched at active gene promoters and potential enhancers in mammalian cell genomes. However, the cellular enzymes that regulate the addition and removal of Kcr are unknown, which has hindered further investigation of its cellular functions. Here we used a chemical proteomics approach to comprehensively profile 'eraser' enzymes that recognize a lysine-4 crotonylated histone H3 (H3K4Cr) mark. We found that Sirt1, Sirt2, and Sirt3 can catalyze the hydrolysis of lysine crotonylated histone peptides and proteins. More importantly, Sirt3 functions as a decrotonylase to regulate histone Kcr dynamics and gene transcription in living cells. This discovery not only opens opportunities for examining the physiological significance of histone Kcr, but also helps to unravel the unknown cellular mechanisms controlled by Sirt3, that have previously been considered solely as a deacetylase.
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Chlorella zofingiensis as an alternative microalgal producer of astaxanthin: biology and industrial potential.
Mar Drugs
PUBLISHED: 04-03-2014
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Astaxanthin (3,3'-dihydroxy-?,?-carotene-4,4'-dione), a high-value ketocarotenoid with a broad range of applications in food, feed, nutraceutical, and pharmaceutical industries, has been gaining great attention from science and the public in recent years. The green microalgae Haematococcus pluvialis and Chlorella zofingiensis represent the most promising producers of natural astaxanthin. Although H. pluvialis possesses the highest intracellular astaxanthin content and is now believed to be a good producer of astaxanthin, it has intrinsic shortcomings such as slow growth rate, low biomass yield, and a high light requirement. In contrast, C. zofingiensis grows fast phototrophically, heterotrophically and mixtrophically, is easy to be cultured and scaled up both indoors and outdoors, and can achieve ultrahigh cell densities. These robust biotechnological traits provide C. zofingiensis with high potential to be a better organism than H. pluvialis for mass astaxanthin production. This review aims to provide an overview of the biology and industrial potential of C. zofingiensis as an alternative astaxanthin producer. The path forward for further expansion of the astaxanthin production from C. zofingiensis with respect to both challenges and opportunities is also discussed.
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Strain and structure heterogeneity in MoS2 atomic layers grown by chemical vapour deposition.
Nat Commun
PUBLISHED: 03-21-2014
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Monolayer molybdenum disulfide (MoS2) has attracted tremendous attention due to its promising applications in high-performance field-effect transistors, phototransistors, spintronic devices and nonlinear optics. The enhanced photoluminescence effect in monolayer MoS2 was discovered and, as a strong tool, was employed for strain and defect analysis in MoS2. Recently, large-size monolayer MoS2 has been produced by chemical vapour deposition, but has not yet been fully explored. Here we systematically characterize chemical vapour deposition-grown MoS2 by photoluminescence spectroscopy and mapping and demonstrate non-uniform strain in single-crystalline monolayer MoS2 and strain-induced bandgap engineering. We also evaluate the effective strain transferred from polymer substrates to MoS2 by three-dimensional finite element analysis. Furthermore, our work demonstrates that photoluminescence mapping can be used as a non-contact approach for quick identification of grain boundaries in MoS2.
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Electrocardiographic Difference between Ventricular Arrhythmias from the Right Ventricular Outflow Tract and Idiopathic Right Ventricular Arrhythmias.
Pacing Clin Electrophysiol
PUBLISHED: 02-27-2014
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Ventricular arrhythmias (VA) arising from arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) and idiopathic right ventricular outflow tract ventricular arrhythmias (RVOT-VA) share the pattern of left bundle branch block (LBBB)/inferior axis. The existence of QRS notching showed a discriminating effect of the two conditions in recent research; however, there are little data regarding the difference in the distribution of QRS notching. The aim of this study was to compare the VA morphology between the two conditions, especially evaluating the diagnostic role of QRS notching.
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Length quantization of DNA partially expelled from heads of a bacteriophage T3 mutant.
Virology
PUBLISHED: 02-20-2014
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DNA packaging of phages phi29, T3 and T7 sometimes produces incompletely packaged DNA with quantized lengths, based on gel electrophoretic band formation. We discover here a packaging ATPase-free, in vitro model for packaged DNA length quantization. We use directed evolution to isolate a five-site T3 point mutant that hyper-produces tail-free capsids with mature DNA (heads). Three tail gene mutations, but no head gene mutations, are present. A variable-length DNA segment leaks from some mutant heads, based on DNase I-protection assay and electron microscopy. The protected DNA segment has quantized lengths, based on restriction endonuclease analysis: six sharp bands of DNA missing 3.7-12.3% of the last end packaged. Native gel electrophoresis confirms quantized DNA expulsion and, after removal of external DNA, provides evidence that capsid radius is the quantization-ruler. Capsid-based DNA length quantization possibly evolved via selection for stalling that provides time for feedback control during DNA packaging and injection.
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Agmatine protects against zymosan-induced acute lung injury in mice by inhibiting NF-?B-mediated inflammatory response.
Biomed Res Int
PUBLISHED: 02-16-2014
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Acute lung injury (ALI) is characterized by overwhelming lung inflammation and anti-inflammation treatment is proposed to be a therapeutic strategy for ALI. Agmatine, a cationic polyamine formed by decarboxylation of L-arginine, is an endogenous neuromodulator that plays protective roles in diverse central nervous system (CNS) disorders. Consistent with its neuromodulatory and neuroprotective properties, agmatine has been reported to have beneficial effects on depression, anxiety, hypoxic ischemia, Parkinson's disease, and gastric disorder. In this study, we tested the effect of agmatine on the lung inflammation induced by Zymosan (ZYM) challenge in mice. We found that agmatine treatment relieved ZYM-induced acute lung injury, as evidenced by the reduced histological scores, wet/dry weight ratio, and myeloperoxidase activity in the lung tissue. This was accompanied by reduced levels of TNF-?, IL-1?, and IL-6 in lung and bronchoalveolar lavage fluid and decreased iNOS expression in lung. Furthermore, agmatine inhibited the phosphorylation and degradation of I?B and subsequently blocked the activation of nuclear factor (NF)-?B induced by Zymosan. Taken together, our results showed that agmatine treatment inhibited NF-?B signaling in lungs and protected mice against ALI induced by Zymosan, suggesting agmatine may be a potential safe and effective approach for the treatment of ALI.
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Analysis of multiple transcriptomes of the African oil palm (Elaeis guineensis) to identify reference genes for RT-qPCR.
J. Biotechnol.
PUBLISHED: 01-14-2014
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The African oil palm (Elaeis guineensis), which is grown in tropical and subtropical regions, is a highly productive oil-bearing crop. For gene expression-based analyses such as reverse transcription-quantitative real time PCR (RT-qPCR), reference genes are essential to provide a baseline with which to quantify relative gene expression. Normalization using reliable reference genes is critical in correctly interpreting expression data from RT-qPCR. In order to identify suitable reference genes in African oil palm, 17 transcriptomes of different tissues obtained from NCBI were systematically assessed for gene expression variation. In total, 53 putative candidate reference genes with coefficient of variation values <3.0 were identified: 18 in reproductive tissue and 35 in vegetative tissue. Analysis for enriched functions showed that approximately 90% of identified genes were clustered in cell component gene functions, and 12 out of 53 genes were traditional housekeeping genes. We selected and validated 16 reference genes chosen from leaf tissue transcriptomes by using RT-qPCR in sets of cold, drought and high salinity treated samples, and ranked expression stability using statistical algorithms geNorm, Normfinder and Bestkeeper. Genes encoding actin, adenine phosphoribosyltransferase and eukaryotic initiation factor 4A genes were the most stable genes over the cold, drought and high salinity stresses. Identification of stably expressed genes as reference gene candidates from multiple transcriptome datasets was found to be reliable and efficient, and some traditional housekeeping genes were more stably expressed than others. We provide a useful molecular genetic resource for future gene expression studies in African oil palm, facilitating molecular genetics approaches for crop improvement in this species.
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In situ observation of step-edge in-plane growth of graphene in a STEM.
Nat Commun
PUBLISHED: 01-13-2014
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It is extremely difficult to control the growth orientation of the graphene layer in comparison to Si or III-V semiconductors. Here we report a direct observation of graphene growth and domain boundary formation in a scanning transmission electron microscope, with residual hydrocarbon in the microscope chamber being used as the carbon source for in-plane graphene growth at the step-edge of bilayer graphene substrate. We show that the orientation of the growth is strongly influenced by the step-edge structure and areas grown from a reconstructed 5-7 edge are rotated by 30° with respect to the mother layer. Furthermore, single heteroatoms like Si may act as catalytic active sites for the step-edge growth. The findings provide an insight into the mechanism of graphene growth and defect reconstruction that can be used to tailor carbon nanostructures with desired properties.
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Leptin level and oxidative stress contribute to obesity-induced low testosterone in murine testicular tissue.
Oxid Med Cell Longev
PUBLISHED: 01-07-2014
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This study evaluated the effects of obesity on the function of reproductive organs in male mice and the possible mechanism of male secondary hypogonadism (SH) in obesity.
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Peroxisome Proliferator-Activated Receptor ? Deficiency in T Cells Accelerates Chronic Rejection by Influencing the Differentiation of CD4+ T Cells and Alternatively Activated Macrophages.
PLoS ONE
PUBLISHED: 01-01-2014
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In a previous study, activation of the peroxisome proliferator-activated receptor ? (PPAR?) inhibited chronic cardiac rejection. However, because of the complexity of chronic rejection and the fact that PPAR? is widely expressed in immune cells, the mechanism of the PPAR? - induced protective effect was unclear.
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Microbubbles coupled to methotrexate-loaded liposomes for ultrasound-mediated delivery of methotrexate across the blood-brain barrier.
Int J Nanomedicine
PUBLISHED: 01-01-2014
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Methotrexate (MTX) is the single most effective agent for the treatment of primary central nervous system lymphoma. Currently, the delivery of MTX to the brain is achieved by high systemic doses, which cause severe long-term neurotoxicity, or intrathecal administration, which is highly invasive and may lead to infections or hemorrhagic complications. Acoustically active microbubbles have been developed as drug carriers for the noninvasive and brain-targeted delivery of therapeutics. However, their application is limited by their low drug-loading capacity. To overcome this limitation, we prepared microbubbles coupled to MTX-loaded liposomes using ZHIFUXIAN, a novel type of microbubbles with a superior safety profile and long circulation time. MTX-liposome-coupled microbubbles had a high drug-loading capacity of 8.91%± 0.86%, and their size (2.64 ± 0.93 ?m in diameter) was suitable for intravenous injection. When used with ultrasound, they showed more potent in vitro cytotoxicity against Walker-256 cancer cells than MTX alone or MTX-loaded liposomes. When Sprague-Dawley rats were exposed to sonication, administration of these MTX-liposome-coupled microbubbles via the tail vein led to targeted disruption of the blood-brain barrier without noticeable tissue or capillary damage. High-performance liquid chromatography analysis of the brain MTX concentration showed that MTX delivery to the brain followed the order of MTX-liposome-coupled microbubbles + ultrasound (25.3 ± 2.4 ?g/g) > unmodified ZHIFUXIAN + MTX + ultrasound (18.6 ± 2.2 ?g/g) > MTX alone (6.97 ± 0.75 ?g/g) > MTX-liposome-coupled microbubbles (2.92 ± 0.39 ?g/g). Therefore, treatment with MTX-liposome-coupled microbubbles and ultrasound resulted in a significantly higher brain MTX concentration than all other treatments (P<0.01). These results suggest that MTX-liposome-coupled microbubbles may hold great promise as new and effective therapies for primary central nervous system lymphoma and other central nervous system malignancies.
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Improving Mycobacterium bovis bacillus Calmette-Guèrin as a vaccine delivery vector for viral antigens by incorporation of glycolipid activators of NKT cells.
PLoS ONE
PUBLISHED: 01-01-2014
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Recombinant Mycobacterium bovis bacillus Calmette-Guèrin (rBCG) has been explored as a vector for vaccines against HIV because of its ability to induce long lasting humoral and cell mediated immune responses. To maximize the potential for rBCG vaccines to induce effective immunity against HIV, various strategies are being employed to improve its ability to prime CD8+ T cells, which play an important role in the control of HIV infections. In this study we adopted a previously described approach of incorporating glycolipids that activate CD1d-restricted natural killer T (NKT) cells to enhance priming of CD8+ T cells by rBCG strains expressing an SIV Gag antigen (rBCG-SIV gag). We found that the incorporation of the synthetic NKT activating glycolipid ?-galactosylceramide (?-GC) into rBCG-SIV gag significantly enhanced CD8+ T cell responses against an immunodominant Gag epitope, compared to responses primed by unmodified rBCG-SIV gag. The abilities of structural analogues of ?-GC to enhance CD8+ T cell responses to rBCG were compared in both wild type and partially humanized mice that express human CD1d molecules in place of mouse CD1d. These studies identified an ?-GC analogue known as 7DW8-5, which has previously been used successfully as an adjuvant in non-human primates, as a promising compound for enhancing immunogenicity of antigens delivered by rBCG.vectors. Our findings support the incorporation of synthetic glycolipid activators of NKT cells as a novel approach to enhance the immunogenicity of rBCG-vectored antigens for induction of CD8+ T cell responses. The glycolipid adjuvant 7DW8-5 may be a promising candidate for advancing to non-human primate and human clinical studies for the development of HIV vaccines based on rBCG vectors.
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The tumor-suppressive microRNA-135b targets c-myc in osteoscarcoma.
PLoS ONE
PUBLISHED: 01-01-2014
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Osteosarcoma is the most common primary tumor of the bone. It leads to many deaths because of its rapid proliferation and metastasis. Recent studies have shown that microRNAs are important gene regulators that are involved in various cancer-related processes. In this study, we found that miR-135b was down-regulated in both osteoscarcoma patient tumor tissues and osteoscarcoma cell lines in comparison to paired adjacent non-tumor bone tissue. We observed that a lower level of miR-135b was associated with metastasis. The ectopic expression of miR-135b markedly suppressed osteoscarcoma cell proliferation, migration, and invasion. Conversely, the inhibition of miR-135b expression dramatically accelerated cell proliferation, migration, and invasion. The forced expression of miR-135b in osteosarcoma cells resulted in a significant reduction in the protein level of c-Myc and repressed the activity of a luciferase reporter that contained the 3'-untranslated region of the c-Myc mRNA. These effects were abolished by the mutation of the predicted miR-135b-binding site, which indicates that c-Myc may be a miR-135b target gene. Moreover, the ectopic expression of c-Myc partially reversed the inhibition of cell proliferation and invasion that was caused by miR-135b. These data therefore suggest that miR-135b may function as a tumor suppressor to regulate osteosarcoma cell proliferation and invasion through a mechanism that targets the c-Myc oncogene. These findings indicate that miR-135b may play a role in the pathogenesis of osteosarcoma.
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Preparation of anti-tumor nanoparticle and its inhibition to peritoneal dissemination of colon cancer.
PLoS ONE
PUBLISHED: 01-01-2014
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5-Fluorouracil (5-FU) is one of the most classic chemotherapy drugs. Nanoparticle drug delivery vehicles offer superiority over target effect enhancement and abatement of side effects. Little is known however as to the specific effect of nanoparticle on peritoneal dissemination of colon cancer. The aim of this study is to prepare one NPs (nanoparticles) loaded with 5-FU and investigate the characteristic of NPs and the role of it in peritoneal metastasis nodules formation of human colon cancer.
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Hemostatic effects of microbubble-enhanced low-intensity ultrasound in a liver avulsion injury model.
PLoS ONE
PUBLISHED: 01-01-2014
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Microbubble-enhanced therapeutic ultrasound (MEUS) can block the blood flow in the organs. The aim of this study was to evaluate the hemostatic effect of microbubble-enhanced pulsed, low-intensity ultrasound in a New Zealand White rabbit model of avulsion trauma of the liver. The therapeutic ultrasound (TUS) transducer was operated with the frequency of 1.2 MHz and an acoustic pressure of 3.4 MPa. Microbubble-(MB) enhanced ultrasound (MEUS) (n?=?6) was delivered to the distal part of the liver where the avulsion was created. Livers were treated by TUS only (n?=?4) or MB only (n?=?4) which served as controls. Bleeding rates were measured and contrast enhanced ultrasound (CEUS) was performed to assess the hemostatic effect, and liver hemoperfusion before and after treatment. Generally, bleeding rates decreased more than 10-fold after the treatment with MEUS compared with those of the control group (P<0.05). CEUS showed significant declines in perfusion. The peak intensity value and the area under the curve also decreased after insonation compared with those of the control group (P<0.05). Histological examination showed cloudy and swollen hepatocytes, dilated hepatic sinusoids, perisinusoidal spaces with erythrocyte accumulation in small blood vessels, obvious hemorrhage around portal areas and scattered necrosis in liver tissues within the insonation area of MEUS Group. In addition, necrosis was found in liver tissue 48 h after insonation. We conclude that MEUS might provide an effective hemostatic therapy for serious organ trauma such as liver avulsion injury.
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Ultrasound effects on the assembly of casein micelles in reconstituted skim milk.
J. Dairy Res.
PUBLISHED: 12-19-2013
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Reconstituted skim milks (10 % w/w total solids, pH 6·7-8·0) were ultrasonicated (20, 400 or 1600 kHz at a specific energy input of 286 kJ/kg) at a bulk milk temperature of <30 °C. Application of ultrasound to milk at different pH altered the assembly of the casein micelle in milk, with greater effects at higher pH and lower frequency. Low frequency ultrasound caused greater disruption of casein micelles causing release of protein from the micellar to the serum phase than high frequency. The released protein re-associated to form aggregates of smaller size but with surface charge similar to the casein micelles in the original milk. Ultrasound may be used as a physical intervention to alter the size of the micelles and the partitioning of caseins between the micellar and serum phases in milk. The altered protein equilibria induced by ultrasound treatment may have potential for the development of milk with novel functionality.
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Active Tunable 002.Absorption Enhancement with Graphene Nanodisk Arrays.
Nano Lett.
PUBLISHED: 12-18-2013
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If not for its inherently weak optical absorption at visible and infrared wavelengths, graphene would show exceptional promise for optoelectronic applications. Here we show that by nanopatterning a graphene layer into an array of closely packed graphene nanodisks, its absorption efficiency can be increased from less than 3% to 30% in the infrared region of the spectrum. We examine the dependence of the enhanced absorption on nanodisk size and interparticle spacing. By incorporating graphene nanodisk arrays into an active device, we demonstrate that this enhanced absorption efficiency is voltage-tunable, indicating strong potential for nanopatterned graphene as an active medium for infrared electro-optic devices.
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Using the Plasmon Linewidth To Calculate the Time and Efficiency of Electron Transfer between Gold Nanorods and Graphene.
ACS Nano
PUBLISHED: 12-03-2013
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We present a quantitative analysis of the electron transfer between single gold nanorods and monolayer graphene under no electrical bias. Using single-particle dark-field scattering and photoluminescence spectroscopy to access the homogeneous linewidth, we observe broadening of the surface plasmon resonance for gold nanorods on graphene compared to nanorods on a quartz substrate. Because of the absence of spectral plasmon shifts, dielectric interactions between the gold nanorods and graphene are not important and we instead assign the plasmon damping to charge transfer between plasmon-generated hot electrons and the graphene that acts as an efficient acceptor. Analysis of the plasmon linewidth yields an average electron transfer time of 160 ± 30 fs, which is otherwise difficult to measure directly in the time domain with single-particle sensitivity. In comparison to intrinsic hot electron decay and radiative relaxation, we furthermore calculate from the plasmon linewidth that charge transfer between the gold nanorods and the graphene support occurs with an efficiency of ?10%. Our results are important for future applications of light harvesting with metal nanoparticle plasmons and efficient hot electron acceptors as well as for understanding hot electron transfer in plasmon-assisted chemical reactions.
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Synthesis of chiral metal oxide complexes with tunable electron transition-based optical activity.
Chem. Commun. (Camb.)
PUBLISHED: 11-07-2013
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Chiral metal oxide complexes with tunable optical response to circularly polarised light over the full range of the UV-Vis absorption band were synthesised. This optical activity was attributed to electronic transitions from the ground state to the excited state or from the valence band to the conduction band under an asymmetric electric field.
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Probing spatially dependent photoinduced charge transfer dynamics to TiO2 nanoparticles using single quantum dot modified atomic force microscopy tips.
Nano Lett.
PUBLISHED: 10-31-2013
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Using single CdSe/CdS quantum dot (QD) functionalized atomic force microscopy (AFM) tips, we demonstrate that the spatial dependence of photoinduced electron transfer dynamics from the single QD to TiO2 nanoparticles can be controlled and probed with high spatial (subdiffraction-limited) and temporal (limited by fluorescence microscopy) resolutions. This finding suggests the feasibility of using electron donor or acceptor modified AFM tips for simultaneous high resolution imaging of morphology and photoinduced charge transfer dynamics in nanomaterials.
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Building 3D structures of vanadium pentoxide nanosheets and application as electrodes in supercapacitors.
Nano Lett.
PUBLISHED: 10-22-2013
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Various two-dimensional (2D) materials have recently attracted great attention owing to their unique properties and wide application potential in electronics, catalysis, energy storage, and conversion. However, large-scale production of ultrathin sheets and functional nanosheets remains a scientific and engineering challenge. Here we demonstrate an efficient approach for large-scale production of V2O5 nanosheets having a thickness of 4 nm and utilization as building blocks for constructing 3D architectures via a freeze-drying process. The resulting highly flexible V2O5 structures possess a surface area of 133 m(2) g(-1), ultrathin walls, and multilevel pores. Such unique features are favorable for providing easy access of the electrolyte to the structure when they are used as a supercapacitor electrode, and they also provide a large electroactive surface that advantageous in energy storage applications. As a consequence, a high specific capacitance of 451 F g(-1) is achieved in a neutral aqueous Na2SO4 electrolyte as the 3D architectures are utilized for energy storage. Remarkably, the capacitance retention after 4000 cycles is more than 90%, and the energy density is up to 107 W·h·kg(-1) at a high power density of 9.4 kW kg(-1).
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Surgical therapy for craniocerebral firearm injury.
Turk Neurosurg
PUBLISHED: 10-09-2013
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The current study aims to explore the clinical characteristics of craniocerebral firearm injury and to improve the diagnosis and treatment of this condition.
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Controlled display of enzyme activity with a stretchable hydrogel.
Chem. Commun. (Camb.)
PUBLISHED: 09-14-2013
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An enzyme-incorporated hydrogel made of alginate and polyacrylamide shows a linearly increased activity with the enlargement of surface area upon stretching.
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Sensitivity of graphene edge states to surface adatom interactions.
Nano Lett.
PUBLISHED: 09-06-2013
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Electron beam irradiation at 60 kV is used to open holes in graphene and expose fresh clean edges for further examination by electron energy loss spectroscopy (EELS) at the single atom level combined with scanning transmission electron microscopy (STEM). We show that light element surface adatoms attached on top of the edges of graphene influence the carbon K-edge EELS. A single nitrogen adatom on graphene was imaged by STEM and chemically identified by EELS. We also extend this study to small graphene nanoribbons, termed nanoconstrictions. The arrival of surface adatoms disrupt the detection of unique carbon edge states present in both single edges and in the nanoconstrictions. The spatial distribution of the EELS signals is also examined. These results show that edge states in graphene are highly sensitive to single atom functionalization and sheds light on their long-term stability.
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The multiple chemokine-binding Bovine Herpesvirus 1 Glycoprotein G (BHV1gG) inhibits polymorphonuclear cell but not monocyte migration into inflammatory sites.
Mol. Med.
PUBLISHED: 08-28-2013
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Chemokines facilitate the recruitment of inflammatory cells into tissues, contributing to target organ injury in a wide range of inflammatory and autoimmune diseases. Targeting either single chemokines or chemokine receptors alters the progression of disease in animal models of rheumatoid arthritis and lupus with varying degrees of efficacy but clinical trials in humans have been less successful. Given the redundancy of chemokine-chemokine receptor interactions, targeting of more than one chemokine may be required to inhibit active inflammatory disease. To test the effects of multiple-chemokine blockade in inflammation, we generated an adenovirus expressing bovine herpesvirus 1 glycoprotein G (BHV1gG), a viral chemokine antagonist that binds to a wide spectrum of murine and human chemokines, fused to the Fc portion of murine IgG2a. Administration of the adenovirus significantly inhibited thioglycollate-induced migration of polymorphonuclear leukocytes into the peritoneal cavity of BALB/c mice and reduced both clinical severity and articular damage in K/BxN serum transfer-induced arthritis. However, treatment with BHV1gG-Ig fusion protein did not prevent monocyte infiltration into the peritoneum in the thioglycollate model and did not prevent renal monocyte infiltration or nephritis in lupus-prone NZB/W mice. These observations suggest that the simultaneous inhibition of multiple chemokines by BHV1gG has the potential to interfere with acute inflammatory responses mediated by polymorphonuclear leukocytes, but is less effective in chronic inflammatory disease mediated by macrophages.
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Directed evolution of a virus exclusively utilizing human epidermal growth factor receptor as the entry receptor.
J. Virol.
PUBLISHED: 08-07-2013
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Rational design and directed evolution are powerful tools to generate and improve protein function; however, their uses are mostly limited to enzyme and antibody engineering. Here we describe a directed-evolution strategy, named the tandem selection and enrichment system (TSES), and its use in generating virus with exclusive specificity for a particular cellular receptor. In TSES, evolving viruses are sequentially and iteratively transferred between two different host cells, one for selection of receptor specificity and the other for enrichment of the fittest virus. By combining rational design and TSES, we generated human epidermal growth factor receptor (EGFR)-specific virus 1 (ESV1). ESV1 has the backbone of Sindbis virus (SINV) and displays an EGF domain engrafted onto structural protein E2 after residue Pro192, together with eight amino acid changes stabilizing the E2-EGF chimera. ESV1 uses EGFR to initiate infection and has lost the capacity to interact with all known SINV receptors. A 12.2-? cryoelectron microscopic (cryoEM) reconstruction of ESV1 reveals that the E2-EGF fusion adopts a fixed conformation, with EGF sitting at the top of the E2 spike; The EGFR binding interface faces outward, and the EGF domain completely masks SINV receptor binding. The cryoEM structure of ESV1 explains the desirable properties of ESV1 and provides insights for its further modification. TSES expands the scope of directed evolution and can be easily extended to other targeting molecules and viral systems.
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Morphological study of Schwann cells remyelination in contused spinal cord of rats.
Chin. J. Traumatol.
PUBLISHED: 08-06-2013
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To study the role and effect of Schwann cells (SCs) remyelination in contused spinal cord.
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Integrins protect cardiomyocytes from ischemia/reperfusion injury.
J. Clin. Invest.
PUBLISHED: 07-18-2013
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Ischemic damage is recognized to cause cardiomyocyte (CM) death and myocardial dysfunction, but the role of cell-matrix interactions and integrins in this process has not been extensively studied. Expression of ?7?1D integrin, the dominant integrin in normal adult CMs, increases during ischemia/reperfusion (I/R), while deficiency of ?1 integrins increases ischemic damage. We hypothesized that the forced overexpression of integrins on the CM would offer protection from I/R injury. Tg mice with CM-specific overexpression of integrin ?7?1D exposed to I/R had a substantial reduction in infarct size compared with that of ?5?1D-overexpressing mice and WT littermate controls. Using isolated CMs, we found that ?7?1D preserved mitochondrial membrane potential during hypoxia/reoxygenation (H/R) injury via inhibition of mitochondrial Ca2+ overload but did not alter H/R effects on oxidative stress. Therefore, we assessed Ca2+ handling proteins in the CM and found that ?1D integrin colocalized with ryanodine receptor 2 (RyR2) in CM T-tubules, complexed with RyR2 in human and rat heart, and specifically bound to RyR2 amino acids 165-175. Integrins stabilized the RyR2 interdomain interaction, and this stabilization required integrin receptor binding to its ECM ligand. These data suggest that ?7?1D integrin modifies Ca2+ regulatory pathways and offers a means to protect the myocardium from ischemic injury.
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Respiratory viral infection in the chronic persistent phase of chronic rhinosinusitis.
Laryngoscope
PUBLISHED: 07-18-2013
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The role of respiratory viral infection in the pathogenesis of chronic rhinosinusitis (CRS) has been rarely studied and remains controversial. The aim of this study was to explore the prevalence of respiratory viruses in the chronic status of CRS.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.