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Find video protocols related to scientific articles indexed in Pubmed.
Microvascular protective role of pericytes in melatonin-treated spinal cord injury in the C57BL/6 mice.
Chin. Med. J.
PUBLISHED: 08-23-2014
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Pericytes, located on microvessels, help to maintain vascular stability and blood-brain barrier integrity. The influence of pericytes on microvessels after spinal cord injury (SCI) is less clear. Therefore, the aim of this study was to investigate whether pericytes took a protective effect on microvessels in melatonin-treated SCI.
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[Gene expression profiling of three tissues of chicken after heat stress treatment by microarray technique].
Yi Chuan
PUBLISHED: 08-22-2014
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In the present study, tissue samples were collected from the cerebrum, liver, and leg muscle of 8-day-old dwarf chicks that were exposed to a 3 h treatment of 28?± 1? (control group) or 40?± 1? (treatment group). Differentially expressed (DE) genes in these samples were detected using whole-genome microarray chips, and their functions were.
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Effects of outlets on cracking risk and integral stability of super-high arch dams.
ScientificWorldJournal
PUBLISHED: 07-23-2014
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In this paper, case study on outlet cracking is first conducted for the Goupitan and Xiaowan arch dams. A nonlinear FEM method is then implemented to study effects of the outlets on integral stability of the Xiluodu arch dam under two loading conditions, i.e., normal loading and overloading conditions. On the basis of the case study and the numerical modelling, the outlet cracking mechanism, risk, and corresponding reinforcement measures are discussed. Furthermore, the numerical simulation reveals that (1) under the normal loading conditions, the optimal distribution of the outlets will contribute to the tensile stress release in the local zone of the dam stream surface and decrease the outlet cracking risk during the operation period. (2) Under the overloading conditions, the cracks initiate around the outlets, then propagate along the horizontal direction, and finally coalesce with those in adjacent outlets, where the yield zone of the dam has a shape of butterfly. Throughout this study, a dam outlet cracking risk control and reinforcement principle is proposed to optimize the outlet design, select the appropriate concrete material, strengthen the temperature control during construction period, design reasonable impounding scheme, and repair the cracks according to their classification.
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Cardioprotective effects of oxymatrine on isoproterenol-induced heart failure via regulation of DDAH/ADMA metabolism pathway in rats.
Eur. J. Pharmacol.
PUBLISHED: 07-22-2014
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The present study was designed to investigate whether oxymatrine could attenuate isoproterenol-induced heart failure via regulation of asymmetric dimethylarginine (ADMA) metabolism in rats. Heart failure model was established by once daily subcutaneous injection of isoproterenol (5mg/kg/d) to rats for 7 days. Simultaneously, oral administration of oxymatrine (25, 50 and 100mg/kg/d, respectively) was started from day 1 to day 7, or with vehicle as corresponding controls. After continuous preventive administration of oxymatrine for 7 days, significant isoproterenol-induced heart failure characterized by hypertrophy and dysfunction of left ventricular, and elevation of brain natruretic peptide (BNP, a heart failure biomarker) and cardiac troponin I (cTn-I, a cardiac injury biomarker) was observed. Preventive oxymatrine significantly ameliorated the cardiac hypertrophy, improved the left ventricular dysfunction and reduced the increased BNP and cTn-I in serum of isoproterenol-treated rats. And obvious changes with decrease of systolic blood pressure and increase of heart rate were present in isoproterenol group and normalized by oxymatrine. Besides, prevention with oxymatrine significantly up-regulated the dimethylarginine dimethylaminohydrolase 2 (DDAH2) expression, which was followed by decreased serum ADMA, but it had no effect on protein arginine methyltransferase1 (PRMT1) expression that is up-regulated in isoproterenol-induced heart failure rats. These results manifested that preventive oxymatrine could ameliorate the hypertrophy and dysfunction of left ventricle of rats with heart failure, which is attributed to modulation of DDAH/ADMA metabolism pathway by oxymatrine.
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GSK3 protein positively regulates type I insulin-like growth factor receptor through forkhead transcription factors FOXO1/3/4.
J. Biol. Chem.
PUBLISHED: 07-22-2014
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Glycogen synthase kinase-3 (GSK3) has either tumor-suppressive roles or pro-tumor roles in different types of human tumors. A number of GSK3 targets in diverse signaling pathways have been uncovered, such as tuberous sclerosis complex subunit 2 and ?-catenin. The O subfamily of forkhead/winged helix transcription factors (FOXO) is known as tumor suppressors that induce apoptosis. In this study, we find that FOXO binds to type I insulin-like growth factor receptor (IGF-IR) promoter and stimulates its transcription. GSK3 positively regulates the transactivation activity of FOXO and stimulates IGF-IR expression. Although kinase-dead GSK3? cannot up-regulate IGF-IR, the constitutively active GSK3? induces IGF-IR expression in a FOXO-dependent manner. Serum starvation or Akt inhibition leads to an increase in IGF-IR expression, which could be blunted by GSK3 inhibition. GSK3? knockdown or GSK3 inhibitor suppresses IGF-I-induced IGF-IR, Akt, and ERK1/2 phosphorylation. Moreover, knockdown of GSK3? or FOXO1/3/4 leads to a decrease in cellular proliferation and abrogates IGF-I-induced hepatoma cell proliferation. These results suggest that GSK3 and FOXO may positively regulate IGF-I signaling and hepatoma cell proliferation.
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SP600125 induces Src and type I IGF receptor phosphorylation independent of JNK.
Int J Mol Sci
PUBLISHED: 07-15-2014
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c-Jun N-terminal kinases (JNK) are members of the mitogen-activated protein kinase (MAPK) family that have important roles in signal transduction. The small molecule SP600125 is widely used in biochemical studies as a JNK inhibitor. However, recent studies indicate that SP600125 may also act independent of JNK. Here, we report that SP600125 can induce Src, type I insulin-like growth factor receptor (IGF-IR), Akt and Erk1/2 phosphorylation. Notably, these effects are independent of its inhibition of JNK. Inhibition of Src abrogates the stimulation of IGF-IR, Akt and Erk1/2 phosphorylation. IGF-IR knockdown blunts the induction of both Akt and Erk1/2 phosphorylation by SP600125. Moreover, combination of SP600125 and the Src inhibitor saracatinib synergistically inhibits cell proliferation. We conclude that SP600125 can activate Src-IGF-IR-Akt/Erk1/2 signaling pathways independent of JNK.
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Comparative research for the dietary pattern of patients with esophageal cancer at different developing stages and the daily intake of vitamin A, E and ?-carotene.
Pak J Pharm Sci
PUBLISHED: 07-13-2014
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This paper discusses the different stages of normal esophageal's developing to esophageal cancer, and the difference among dietary patterns of patients with esophageal cancer and acceptable daily intake of vitamin A, E and beta carotene intake in diet. This paper takes advantage of food composition table, calculates the intake amount of dietary vitamin A, E and beta carotene in all kinds of food for patients with esophageal cancer, and analyzes the intake amount difference of dietary vitamin A, E and beta carotene in each kind of food for different groups of people. Research conclusions: the low content level of dietary vitamin A, E beta-carotene and low intake amount of beans, vegetables and fruit intake may increase the risk of esophageal cancer' occurring, while the relationship among dietary vitamin E, the occurrence and development of esophageal cancer needs further discussion.
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The distinct abilities of tube-formation and migration between brain and spinal cord microvascular pericytes in rats.
Clin. Hemorheol. Microcirc.
PUBLISHED: 06-21-2014
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Pericytes are contractile cells that wrap around the endothelial cells of capillaries throughout the body. They play an important role in regulating the blood brain barrier (BBB) and blood spinal cord barrier (BSCB). The differences between brain and spinal cord microvascular endothelial cells have been investigated. However, no report has elucidated the similarities and differences between brain microvasular pericytes (BMPs) and spinal cord microvascular pericytes (SCMPs) in vitro. The similarities were found between the two types of pericytes not only in the proliferation ability but also in the expression of toll like receptor 4. On the other hand, BMPs showed more than 2 fold in tubular length formation compared with SCMPs. The number of migratory SCMPs was larger than that of migratory BMPs. The expressions of connexin 43 and vascular endothelial growth factor (VEGF) in BMPs were increased compared with those in SCMPs, while SCMPs expressed more desmin and N-cadherin than BMPs. The abilities of tube-formation and migration between BMPs and SCMPs were markedly different, which might be mediated by VEGF, connexin 43, N-cadherin and desmin. These distinguishing features may reflect the more widespread differences between the BBB and BSCB which directly impact pathophysiological processes in various major diseases.
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Shaped multi-cycle two-color laser field for generating an intense isolated XUV pulse toward 100 attoseconds.
Opt Express
PUBLISHED: 06-13-2014
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The isolated attosecond pulse (IAP) generated from high-order harmonic (HH) radiation has been established as an important technique for the ultrafast optics over past decade. The applications of IAP in ultrafast processes can be greatly extended by further developing the high-intensity IAP. Here, we theoretically propose to shape a two-color field by performing peak amplitude-wavelength analysis. It is found that a 240-as IAP can be generated even without carrier envelop phase (CEP) stabilization using a 25 fs/800 nm fundamental field and a relative weak 25 fs/1330 nm control field, which enables us to markedly relax the requirements of the driving laser fields both in pulse duration and CEP control. On the other hand, if the CEPs of driving laser fields are stabilized, a 65-eV broadband continual harmonic, supporting a 81-as IAP, can be directly produced with the optimized intensity ratio of 0.866 and control wavelength of 1400 nm. Moreover, the propagation effect of two-color field on the macroscopic build-up of HH for generating a high-energy IAP is discussed. We found that the method of phase match still works for the efficient continuous harmonic generation as long as the ionization level and the pressure of gas medium are kept low enough. Since the phase-matched short IAP can be generated with our shaped two-color scheme in combination with a relaxed requirement of driving laser fields, the commercial available high-energy laser source with a loosely focused geometry is promising for scaling up the energy of IAP, showing the potential for the realization of IAP with high focused intensity toward 100 attoseconds.
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Environmental effects of heavy metals derived from the e-waste recycling activities in China: A systematic review.
Waste Manag
PUBLISHED: 05-06-2014
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As the world's leading manufacturing country, China has become the largest dumping ground for e-waste, resulting in serious pollution of heavy metals in China. This study reviews recent studies on environmental effects of heavy metals from the e-waste recycling sites in China, especially Taizhou, Guiyu, and Longtang. The intensive uncontrolled processing of e-waste in China has resulted in the release of large amounts of heavy metals in the local environment, and caused high concentrations of metals to be present in the surrounding air, dust, soils, sediments and plants. Though the pollution of many heavy metals was investigated in the relevant researches, the four kinds of heavy metals (Cu, Pb, Cd and Cr) from e-waste recycling processes attracted more attention. The exceedance of various national and international standards imposed negative effects to the environment, which made the local residents face with the serious heavy metal exposure. In order to protect the environment and human health, there is an urgent need to control and monitor the informal e-waste recycling operations.
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Analysis of complications in primary cleft lips and palates surgery.
J Craniofac Surg
PUBLISHED: 04-11-2014
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A series of retrospectively recorded patients with cleft lip and palate was uniquely investigated to demonstrate and analyze the complications after cleft repairing operations in a selected Chinese population.
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Melatonin Treatment Protects Against Acute Spinal Cord Injury-Induced Disruption of Blood Spinal Cord Barrier in Mice.
J. Mol. Neurosci.
PUBLISHED: 04-08-2014
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The spinal cord microcirculation plays a critically important role in maintaining the normal function of spinal cord neurons, glial cells, and axons. Previous researches were largely focused on improved neurological manifestations of spinal cord injury (SCI) while ignoring to improve spinal cord microcirculation disorder after melatonin treatment. Therefore, the mechanism of melatonin that affects blood spinal cord barrier (BSCB) integrity and microcirculation in SCI remains unclear. The present study was performed to investigate the effect of melatonin on the BSCB in a SCI mice model. Melatonin (5, 10, 25, 50, 100 mg/kg i.p.) was administered to mice immediately following SCI. Compared to the 48 h post-SCI group, mice treated with melatonin (50 mg/kg) exhibited significantly reduced BSCB permeability. Additionally, melatonin treatment restrained microvessel loss; attenuated edema; protected the tight junction proteins, endothelial cells, and pericytes; decreased the number of cell apoptosis; and reduced MMP3/AQP4/HIF-1?/VEGF/VEGFR2 expression after SCI. Above all, our results clearly demonstrated that melatonin could stabilize microvascular barrier function and microcirculation of SCI, whose mechanism was to promote the repair of the damaged BSCB.
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Synthesis, characterization and ethylene polymerization behaviour of binuclear nickel halides bearing 4,5,9,10-tetra(arylimino)pyrenylidenes.
Dalton Trans
PUBLISHED: 04-04-2014
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Pyrene-4,5,9,10-tetraone was prepared via the oxidation of pyrene, and reacted with various anilines to afford a series of 4,5,9,10-tetra(arylimino)pyrenylidene derivatives (L1-L4). The tetraimino-pyrene compounds L1 and L2 were reacted with two equivalents of (DME)NiBr2 in CH2Cl2 to afford the corresponding dinickel bromide complexes (Ni1 and Ni2). The organic compounds were fully characterized, whilst the bi-metallic complexes were characterized by FT-IR spectra and elemental analysis. The molecular structures of representative organic and nickel compounds were confirmed by single-crystal X-ray diffraction studies. These nickel complexes exhibited high activities towards ethylene polymerization in the presence of either MAO or Me2AlCl, maintaining a high activity over a prolonged period (longer than previously reported dinickel complex pre-catalysts). The polyethylene obtained was characterized by GPC, DSC and FT-IR spectroscopy and was found to possess branched features.
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DRP-1, ezrin and E-cadherin expression and the association with esophageal squamous cell carcinoma.
Oncol Lett
PUBLISHED: 04-01-2014
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It has been shown that death-associated protein kinase (DAPK) family and E-cadherin play significant roles in the promotion of apoptosis and the suppression of cell adhesion and migration, and are involved in tumor metastasis. Ezrin, a cytoplasmic peripheral membrane protein, has been shown to interact with E-cadherin to participate in the metastasis of tumor cells. The present study aimed to investigate the expression of DRP-1 (a member of the DAPK family), ezrin and E-cadherin in esophageal squamous cell carcinoma (ESCC), and to analyze their association with clinicopathological factors in order to explore their potential in ESCC diagnosis. The expression of these genes was studied in tissue microarrays using in situ hybridization and immunohistochemistry methods in 76 specimens of ESCC and their paracancerous normal squamous epithelium tissues. Expression was statistically analyzed with regard to clinicopathological factors using ?(2) and non-parametric tests. The expression level of DRP-1 was significantly different between the ESCC and paracancerous tissues (P<0.05). The expression level was correlated with the depth of invasion and lymph node metastasis (P<0.05). Abnormal E-cadherin expression was found to be associated with a high degree of cancer differentiation and lymph node metastasis (P<0.05). A positive correlation was observed between the expression of DRP-1 and E-cadherin (P<0.05). The expression of ezrin was found to be correlated with the depth of ESCC invasion, the degree of differentiation and lymph node metastasis (P<0.05). The high expression of ezrin has been previously shown to be correlated with the low or absent expression of E-cadherin. In conclusion, in ESCC, the expression levels of DRP-1, ezrin and E-cadherin were all reduced, and this reduction or absence of expression may have been attributed to ESCC tumorigenesis and progression. Simultaneous analyses of DRP-1, ezrin and E-cadherin expression levels would be useful to determine the malignancy and metastatic potential of ESCC, and these genes are consequently of potential use as biomarkers for the diagnosis and prognosis assessment of early-stage ESCC.
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Novel binding regioselectivity in the interpenetration of a non-symmetric axle into a non-symmetric pillar[5]arene wheel.
Chem. Commun. (Camb.)
PUBLISHED: 04-01-2014
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We describe the regioselective complexation of a non-symmetric 5-bromovaleronitrile axle by a non-symmetric pillar[5]arene bearing different alkyl (methyl and pentyl) rims, forming an oriented interpenetrated complex with the directionality of CN@methyl rim and Br@pentyl rim.
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Simultaneous removal of NOx and SO2 from flue gas using combined Na2SO3 assisted electrochemical reduction and direct electrochemical reduction.
J. Hazard. Mater.
PUBLISHED: 03-28-2014
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A method combining Na2SO3 assisted electrochemical reduction and direct electrochemical reduction using Fe(II)(EDTA) solution was proposed to simultaneously remove NOx and SO2 from flue gas. Activated carbon was used as catalyst to accelerate the process. This new system features (a) direct conversion of NOx and SO2 to harmless N2 and SO4(2-); (b) fast regeneration of Fe(II)(EDTA); (c) minimum use of chemical reagents; and (d) recovery of the reduction by-product (Na2SO4). Fe(II)(EDTA) solution was continuously recycled and reused during entire process, and no harmful waste was generated. Approximately 99% NOx and 98% SO2 were removed under the optimal condition. The stability test showed that the system operation was reliable.
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Probing rotational wave-packet dynamics with the structural minimum in high-order harmonic spectra.
Opt Express
PUBLISHED: 03-26-2014
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We investigate the alignment-dependent high-order harmonic spectrum generated from nonadiabatically aligned molecules around the first half rotational revival. It is found that the evolution of the molecular alignment is encoded in the structural minima. To reveal the relation between the molecular alignment and the structural minimum in the high-order harmonic spectrum, we perform an analysis based on the two-center interference model. Our analysis shows that the structural minimum position depends linearly on the inverse of the alignment parameter 2?>. This linear relation indicates the possibility of probing the rotational wave-packet dynamics by measuring the spectral minima.
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Generation of few-cycle infrared pulses from a degenerate dual-pump OPCPA.
Opt Express
PUBLISHED: 03-26-2014
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A degenerate dual-pump optical parametric chirped-pulse amplifier (OPCPA) for generation of few-cycle intense pulses centered at 1.6 ?m is theoretically investigated. By adding the optimized linear chirp to the two pump pulses from Ti:sapphire source and carefully adjusting the delays between the two pumps and seed, the long- and short-wavelength components of the seed pulse are efficiently amplified during the parametric process. Our simulations show that a broadband spectrum spanning from 1.3 ?m to 2.1 ?m is attained with a conversion efficiency of 22.6%. Signal pulse with a near transform-limited (TL) duration of 10.1 fs can be achieved by simply removing the linear chirp from the output signal. Besides, the compressed signal beam manifests good quality both spectrally and temporally, which allows tightly focusing the signal beam for further use.
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Design, synthesis, and preliminary cardioprotective effect evaluation of danshensu derivatives.
Chem Biol Drug Des
PUBLISHED: 02-25-2014
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A series of (R)-3,4-dihydroxyphenyllactic acid Danshensu (DSS) derivatives were synthesized, and their cardioprotective effects were evaluated in vitro and in vivo. Among the new derivatives, compound 14 showed significant protective effects in cultured myocardial cells and in the rat model of myocardial ischemia. The therapeutic efficacy of compound 14 was significantly higher than that of its parent compound DSS, and amlodipine, a first-line treatment for angina pain. Compound 14 potently scavenged free radicals, significantly decreased the levels of LDH and MDA, and inhibited the leakage of CK in animal model of ischemia. We had previously found that compound 14 activated PI3K/Akt/GSK-3? and Nrf2//Keap1/heme oxygenase-1 (HO-1) signaling pathways in H9c2 cells. These results suggest that compound 14 has a unique mechanism of action, that is, multifunctional. Compound 14 may be a new potential therapy for ischemic heart diseases.
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Nanostructures from the self-assembly of ?-helical peptide amphiphiles.
J. Pept. Sci.
PUBLISHED: 01-30-2014
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Self-assembly of PAs composed of palmitic acid and several repeated heptad peptide sequences, C??H??CO-(IEEYTKK)(n)-NH? (n?=?1-4, represented by PA1-PA4), was investigated systematically. The secondary structures of the PAs were characterized by CD. PA3 and PA4 (n?=?3 and 4, respectively) showed an ?-helical structure, whereas PA1 and PA2 (n?=?1 and 2, respectively) did not display an ?-helical conformations under the tested conditions. The morphology of the self-assembled peptides in aqueous medium was studied by transmission electron microscopy. As the number of heptad repeats in the PAs increased, the nanostructure of the self-assembled peptides changed from nanofibers to nanovesicles. Changes of the secondary structures and the self-assembly morphologies of PA3 and PA4 in aqueous medium with various cations were also studied. The critical micelle concentrations were determined using a pyrene fluorescence probe. In conclusion, this method may be used to design new peptide nanomaterials.
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A systematic review of the human body burden of e-waste exposure in China.
Environ Int
PUBLISHED: 01-14-2014
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As China is one of the countries facing the most serious pollution and human exposure effects of e-waste in the world, much of the population there is exposed to potentially hazardous substances due to informal e-waste recycling processes. This report reviews recent studies on human exposure to e-waste in China, with particular focus on exposure routes (e.g. dietary intake, inhalation, and soil/dust ingestion) and human body burden markers (e.g. placenta, umbilical cord blood, breast milk, blood, hair, and urine) and assesses the evidence for the association between such e-waste exposure and the human body burden in China. The results suggest that residents in the e-waste exposure areas, located mainly in the three traditional e-waste recycling sites (Taizhou, Guiyu, and Qingyuan), are faced with a potential higher daily intake of these pollutants than residents in the control areas, especially via food ingestion. Moreover, pollutants (PBBs, PBDEs, PCBs, PCDD/Fs, and heavy metals) from the e-waste recycling processes were all detectable in the tissue samples at high levels, showing that they had entered residents' bodies through the environment and dietary exposure. Children and neonates are the groups most sensitive to the human body effects of e-waste exposure. We also recorded plausible outcomes associated with exposure to e-waste, including 7 types of human body burden. Although the data suggest that exposure to e-waste is harmful to health, better designed epidemiological investigations in vulnerable populations, especially neonates and children, are needed to confirm these associations.
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Impact of XRCC2 Arg188His polymorphism on cancer susceptibility: a meta-analysis.
PLoS ONE
PUBLISHED: 01-01-2014
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Association between the single nucleotide polymorphism rs3218536 (known as Arg188His) located in the X-ray repair cross complementing group 2 (XRCC2) gene and cancer susceptibility has been widely investigated. However, results thus far have remained controversial. A meta-analysis was performed to identify the impact of this polymorphism on cancer susceptibility.
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Correlated multielectron dynamics in mid-infrared laser pulse interactions with neon atoms.
Opt Express
PUBLISHED: 10-10-2013
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The multielectron dynamics in nonsequential triple ionization (NSTI) of neon atoms driven by mid-infrared (MIR) laser pulses is investigated with the three-dimensional classical ensemble model. In consistent with the experimental result, our numerical result shows that in the MIR regime, the triply charged ion longitudinal momentum spectrum exhibits a pronounced double-hump structure at low laser intensity. Back analysis reveals that as the intensity increases, the responsible triple ionization channels transform from direct (e, 3e) channel to the various mixed channels. This transformation of the NSTI channels leads to the results that the shape of ion momentum spectra becomes narrow and the distinct maxima shift towards low momenta with the increase of the laser intensity. By tracing the triply ionized trajectories, the various ionization channels at different laser intensities are clearly identified and these results provide an insight into the complex dynamics of the correlated three electrons in NSTI.
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Copper-Mediated Amidation of Alkenylzirconocenes with Acyl Azides: Formation of Enamides.
Org. Lett.
PUBLISHED: 10-01-2013
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Copper-mediated amidation of alkenylzirconocenes generated in situ from alkynes and zirconocenes with acyl azides is accomplished under mild conditions. The reaction can be used to prepare various enamides.
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TORC1 signaling is governed by two negative regulators in fission yeast.
Genetics
PUBLISHED: 08-09-2013
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The target of rapamycin (TOR) is a highly conserved protein kinase that regulates cell growth and metabolism. Here we performed a genome-wide screen to identify negative regulators of TOR complex 1 (TORC1) in Schizosaccharomyces pombe by isolating mutants that phenocopy ?tsc2, in which TORC1 signaling is known to be up-regulated. We discovered that ?npr2 displayed similar phenotypes to ?tsc2 in terms of amino acid uptake defects and mislocalization of the Cat1 permease. However, ?npr2 and ?tsc2 clearly showed different phenotypes in terms of rapamycin supersensitivity and Isp5 transcription upon various treatments. Furthermore, we showed that Tor2 controls amino acid homeostasis at the transcriptional and post-transcriptional levels. Our data reveal that both Npr2 and Tsc2 negatively regulate TORC1 signaling, and Npr2, but not Tsc2, may be involved in the feedback loop of a nutrient-sensing pathway.
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Maturation inside and outside bone marrow dendritic cells (BMDCs) modulated by interferon-? (IFN-?).
Int. Immunopharmacol.
PUBLISHED: 08-03-2013
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Interferons are made by cells in response to appropriate stimuli such as viruses, bacteria, parasites or tumor cells and are released into the surrounding medium. They then bind to receptors on target cells to allow for communication between cells to trigger the protective defenses of the immune system that eradicate pathogens or tumors. IFN-? is produced by leukocytes and is mainly involved in innate immune response against viral or bacterial infections and for tumor control. The aim of this work is to explore the detailed modulation of IFN-? on phenotypic and functional maturation inside and outside murine bone marrow derived dendritic cells (BMDCs). The maturity of BMDCs post treatment with IFN-? was evaluated with conventional light microscope and transmission electron microscopy (TEM) for morphology changes; flow cytometry (FCM) for changes of surface molecules on BMDCs; cytochemistry, acid phosphatase activity (ACP) test, and FITC-dextran bio-assay for biochemistry analysis and enzyme-linked immunosorbent assay (ELISA) for cytokine production by BMDCs. We have shown that IFN-? 1) up-regulates the expression of MHC II, CD40, CD83, CD80 and CD86 molecules on BMDCs; 2) down-regulates the rates of pinocytosis and phagocytosis by BMDCs as evidenced by the results of decreased ACP, and FITC-dextran bio-assay; 3) enhances the ability of BMDCs to drive T cell function; and 4) induces higher levels of IL-12 and TNF-? secreted by BMDCs. Therefore, we conclude that IFN-? can efficiently promote the maturation of BMDCs through detailed modulation inside and outside BMDCs. Our study has provided more detailed data on changes of BMDCs modulated by IFN-?, and rationale on future application of IFN-? for enhancing host immunity and potent adjuvant administration in the design of DC-based vaccines.
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Spray absorption and electrochemical reduction of nitrogen oxides from flue gas.
Environ. Sci. Technol.
PUBLISHED: 08-02-2013
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This work developed an electrochemical reduction system which can effectively scrub NO× from flue gas by using aqueous solution of Fe(II)(EDTA) (ethylenediaminetetraacetate) as absorbent and electrolyte. This new system features (a) complete decomposition of NOX to harmless N2; and (b) fast regeneration of Fe(II)(EDTA) through electrochemical reaction. The Fe(II)(EDTA) solution was recycled and reused continuously during entire process, and no harmful waste was generated. The reaction mechanism was thoroughly investigated by using voltammetric, chromatographic and spectroscopic approaches. The operating conditions of the system were optimized based on NOX removal efficiency. Approximately 98% NO removal was obtained at the optimal condition. The interference of SO2 in flue gas and the system operating stability was also evaluated.
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Greenhouse gas emissions of alternative pavement designs: Framework development and illustrative application.
J. Environ. Manage.
PUBLISHED: 07-14-2013
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Pavement rehabilitation is carbon intensive and the choice of pavement type is a critical factor in controlling greenhouse gas (GHG) emissions. The existing body of knowledge is not able to support decision-making on pavement choice due to a lack of consensus on the system boundaries, the functional units and the estimation periods. Excessive data requirements further inhibit the generalization of the existing methodologies for design evaluation at the early planning stage. This study proposes a practical life-cycle GHG estimation approach, which is arguably effective to benchmark pavement emissions given project bid tabulation. A set of case studies conducted for this study suggest that recycled asphalt pavement (e.g., foam stabilized base (FSB), and warm mix asphalt (WMA)) would prevent up to 50% of GHGs from the initial construction phase. However, from a life-cycle perspective, pavement emissions are dictated largely by the traffic characteristics and the analysis period for the use phase. The benefits from using recycled materials (e.g., FSB) are likely to diminish if the recycled products do not perform as well as those properly proportioned with less recycled materials, or if the recycled materials are locally unavailable. When the AADT reaches 10,000, use phase releases more than 97% of the life cycle emissions and the emissions difference among alternative designs will be within 1%.
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Physicochemical characterization of a high molecular weight bioactive ?-d-glucan from the fruiting bodies of Ganoderma lucidum.
Carbohydr Polym
PUBLISHED: 06-22-2013
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A purified polysaccharide coded as GLP20 was obtained by precipitating a hot-water extract from Ganoderma lucidum fruiting bodies with 20% (V/V) ethanol. Its total carbohydrate content was 95.9%. Structural analysis showed that GLP20 was a ?-(1?3)-linked d-glucan with a (1?6)-?-d-glucopyranosyl side-branching unit on every third residue. Cell culture study revealed that GLP20 can significantly increase NO production of RAW264.7 macrophages. The analysis of light scattering and high performance size exclusion chromatography (HPSEC) showed that the molecular weight and polydispersity of GLP20 was 3.75×10(6)Da and 1.36, respectively. GLP20 had a rigid chain conformation in aqueous solution. A conformation transition occurred in the alkaline solution with NaOH concentration larger than 0.15M. The transition from ordered structure to single chain happened when GLP20 was heated above 135°C in water solution and was irreversible as demonstrated by differential scanning calorimetry (DSC). GLP20 existed as random coils in DMSO.
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Contribution of recollision ionization to the cross-shaped structure in nonsequential double ionization.
Opt Express
PUBLISHED: 05-15-2013
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With the three-dimensional classical ensemble model, we investigate the correlated electron emission in nonsequential double ionization (NSDI) of argon atoms by few-cycle laser pulses. Our calculations well reproduce the experimentally observed cross-shaped structure in the correlated two-electron momentum spectrum [ Nature Commun. 3, 813 (2012)]. By tracing these NSDI trajectories, we find that besides the process of recollision-induced excitation with subsequent ionization just before the next field maximum, the recollision ionization also significantly contributes to the cross-shaped structure.
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Ammonia solution strengthened three-dimensional macro-porous graphene aerogel.
Nanoscale
PUBLISHED: 05-15-2013
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Recently, many approaches were applied for assembling graphene sheets into a three-dimensional structure. However, it is still a great challenge to obtain a three-dimensional macroporous graphene network with high mechanical strength after drying. Herein, an ammonia strengthened three-dimensional graphene aerogel was prepared. Based on graphene chemistry and ice physics, the mechanical strength of graphene aerogel was improved greatly when the graphene hydrogel was treated by ammonia solution at an ambient temperature. The results demonstrated that the three-dimensional structure of graphene aerogels was destroyed thoroughly without ammonia solution treatment; conversely, the three-dimensional structure was maintained and the compressive strength was improved to 152 kPa at the static load after it was treated by ammonia solution at 90 °C for only 1 h. This phenomenon is due to two reasons: (1) the low freezing point of ammonia solution, which effectively retarded its freezing and then kept the porous structure undestroyed; (2) the reaction between ammonia and graphene hydrogel, which brought some covalent bonds among graphene sheets. We believe our efforts may pave the way for the development and application of three-dimensional graphene based materials.
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Copper-mediated electrophilic imination of alkenylzirconocenes with O-benzoyl ketoximes and aldoximes.
Chem. Commun. (Camb.)
PUBLISHED: 05-10-2013
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Copper-mediated electrophilic imination of alkenylzirconocenes generated in situ from alkynes and zirconocenes is accomplished under mild reaction conditions. The reaction can be used to prepare various 2-azadienes.
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Design and application of a rigid quinazolone scaffold based on two-face Bim ?-helix mimicking.
Eur J Med Chem
PUBLISHED: 05-07-2013
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Based on our previous discovery of an anthraquinone scaffold mimicking two faces of Bim ?-helix, we derived a quinazolone scaffold through structure simplification and optimization. It was inferred that a rigid bicyclic ring was necessary and efficient to maintain the two-faced binding mode. A novel dual inhibitor 6c [6,7,8-trihydroxy-3-(2-hydroxy-5-methylbenzyl)-2-phenylquinazolin-4(3H)-one] was obtained based on this scaffold. 6c exhibited dual binding activity with K(i) values of 0.123 ?M for Mcl-1 and 0.179 ?M for Bcl-2.
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Compact dual-crystal optical parametric amplification for broadband IR pulse generation using a collinear geometry.
Opt Express
PUBLISHED: 04-24-2013
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A novel compact dual-crystal optical parametric amplification (DOPA) scheme, collinearly pumped by a Ti:sapphire laser (0.8 ?m), is theoretically investigated for efficiently generating broadband IR pulses at non-degenerate wavelengths (1.2 ?m~1.4 ?m and 1.8 ?m~2.1 ?m). By inserting a pair of barium fluoride (BaF(2)) wedges between two thin ?-barium borate (BBO) crystals, the group velocity mismatch (GVM) between the three interacting pulses can be compensated simultaneously. In this case, the obtained signal spectrum centered at 1.3 ?m is nearly 20% broader and the conversion efficiency is increased, but also the pulse contrast and beam quality are improved due to the better temporal overlap. Furthermore, sub-two-cycle idler pulses with carrier-envelope phase (CEP) fluctuation of sub-100-mrad root mean square (RMS) can be generated. Because a tunable few-cycle IR pulse with millijoule energy is attainable in this scheme, it will contribute to ultrafast community and be particularly useful as a driving or controlling field for the generation of ultrafast coherent x-ray supercontinuum.
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Numerical simulation of ultrasonic enhancement on mass transfer in liquid-solid reaction by a new computational model.
Ultrason Sonochem
PUBLISHED: 04-19-2013
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Mass transfer coefficient is an important parameter in the process of mass transfer. It can reflect the degree of enhancement of mass transfer process in liquid-solid reaction and in non-reactive systems like dissolution and leaching, and further verify the issues by experiments in the reaction process. In the present paper, a new computational model quantitatively solving ultrasonic enhancement on mass transfer coefficient in liquid-solid reaction is established, and the mass transfer coefficient on silicon surface with a transducer at frequencies of 40kHz, 60kHz, 80kHz and 100kHz has been numerically simulated. The simulation results indicate that mass transfer coefficient increases with the increasing of ultrasound power, and the maximum value of mass transfer coefficient is 1.467×10(-4)m/s at 60kHz and the minimum is 1.310×10(-4)m/s at 80kHz in the condition when ultrasound power is 50W (the mass transfer coefficient is 2.384×10(-5)m/s without ultrasound). The extrinsic factors such as temperature and transducer diameter and distance between reactor and ultrasound source also influence the mass transfer coefficient on silicon surface. Mass transfer coefficient increases with the increasing temperature, with the decreasing distance between silicon and central position, with the decreasing of transducer diameter, and with the decreasing of distance between reactor and ultrasound source at the same ultrasonic power and frequency. The simulation results indicate that the computational model can quantitatively solve the ultrasonic enhancement on mass transfer coefficient.
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Influence of large permanent dipoles on molecular orbital tomography.
Opt Express
PUBLISHED: 03-14-2013
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The influence of large permanent dipoles on molecular orbital tomography via high-order harmonic generation (HHG) is investigated in this work. It is found that, owing to the modification of the angle-dependent ionization rate resulting from the Stark shift, the one-side-recollision condition for the tomographic imaging can not be satisfied even with the few-cycle driving pulses. To overcome this problem, we employ a tailored driving pulse by adding a weak low-frequency pulse to the few-cycle laser pulse to control the HHG process and the recollision of the continuum electrons are effectively restricted to only one side of the core. Then we carried out the orbital reconstruction in both the length and velocity forms. The results show that, the orbital structure can only be successfully reproduced by using the dipole matrix elements projected perpendicular to the permanent dipole in both forms.
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Anomalous isotopic effect on electron-directed reactivity by a 3-?m midinfrared pulse.
Opt Express
PUBLISHED: 03-14-2013
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We have theoretically studied the effect of nuclear mass on electron localization in dissociating H?? and its isotopes subjected to a few-cycle 3-?m pulse. Our results reveal an anomalous isotopic effect in which the degree of electron-directed reactivity can be even higher for heavier isotopes in the intense midinfrared field. We show, for the first time, the pronounced electron localization can be established through the interferences among the multi-photon coupling channels. Due to the relative enhancement of higher-order coupling channels with growing mass, the interference maxima at different kinetic energy of the spectra gradually become in phase, ultimately resulting in the larger dissociation asymmetries of heavier isotopes.
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Quantum-orbit analysis for yield and ellipticity of high order harmonic generation with elliptically polarized laser field.
Opt Express
PUBLISHED: 03-14-2013
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We perform a quantum-orbit analysis for the dependence of high-order-harmonic yield on the driving field ellipticity and the polarization properties of the generated high harmonics. The electron trajectories responsible for the emission of particular harmonics are identified. It is found that, in elliptically polarized driving field, the electrons have ellipticity-dependent initial velocities, which lead to the decrease of the ionization rate. Thus the harmonic yield steeply decreases with laser ellipticity. Besides, we show that the polarization properties of the harmonics are related to the complex momenta of the electron. The physical origin of the harmonic ellipticity is interpreted as the consequence of quantum-mechanical uncertainty of the electron momentum. Our results are verified with the experimental results as well as the numerical solutions of the time dependent Schrödinger equation from the literature.
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Ultra-broadband water window supercontinuum generation with high efficiency in a three-color laser field.
Opt Express
PUBLISHED: 03-14-2013
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We propose an efficient method to generate an ultra-broadband supercontinuum by using a three-color field synthesized by a 1600 nm driving pulse and two weak (3200 nm and 400 nm) control pulses. The results show that the acceleration and ionization steps in the HHG process are simultaneously controlled in our scheme, which can not only broaden the bandwidth but also enhance the harmonic yields of the generated spectrum. Thus a high-efficiency supercontinuum with the photon energies ranging from 205 eV to 480 eV is observed. Based on our 3D propagation simulations, we show that the short quantum path of the supercontinuum is well phase-matched and can be selected under suitable propagation conditions. Thereby, the modulation due to quantum path interference is largely reduced and intense isolated sub-100 as pulses with tunable central wavelengths are directly obtained within water window spectral region.
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Cathepsin B inhibition attenuates cardiac dysfunction and remodeling following myocardial infarction by inhibiting the NLRP3 pathway.
Mol Med Rep
PUBLISHED: 01-30-2013
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Recently, cathepsin B has been demonstrated to be involved in myocardial infarction (MI). This study aimed to elucidate the effects of a specific cathepsin B inhibitor, CA-074Me, on cardiac dysfunction, remodeling and fibrosis following MI in a rat model. Furthermore, the potential mechanisms of action of this inhibitor were investigated. In the present study, Sprague-Dawley rats were anesthetized and subjected to a sham operation or left anterior descending coronary artery ligation, followed by intraperitoneal injection of CA-074Me (10 mg/kg/day) or an equal volume of vehicle for 4 weeks. Activation of the cathepsin B and NLRP3 pathway was detected. Cardiac function was assessed by echocardiography, while hypertrophy and fibrosis were determined by Massons trichrome, immunofluorescence and morphometry. The results demonstrated that cathepsin B-NLRP3 activation was inhibited by CA-074Me treatment. Following such treatment for 4 weeks, the rats demonstrated smaller decreases in cardiac function, and a decrease in cardiomyocyte hypertrophy and the level of fibrosis. Cathepsin B inhibition significantly attenuated cardiac dysfunction, and reduced cardiomyocyte size and cardiac fibrosis in the experimental MI model, by inhibiting NLRP3 activation. This suggested that targeting the cathepsin B-NLRP3 pathway may represent a novel therapeutic strategy to prevent heart failure and remodeling following MI.
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Promoter hypermethylation of ARID1A gene is responsible for its low mRNA expression in many invasive breast cancers.
PLoS ONE
PUBLISHED: 01-21-2013
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ARID1A (AT-rich interactive domain 1A) has recently been identified as a tumor suppressor gene. Its mRNA expression is significantly low in many breast cancers; this is often associated with more aggressive phenotypes. However, the underlying molecular mechanism for its low expression has not been fully understood. This study was undertaken to evaluate the contribution of gene copy number variation, mutations, promoter methylation and histone modification to ARID1As low expression. 38 pairs of breast invasive ductal carcinomas and their normal breast tissue counterparts from the same patients were randomly selected for gene expression and copy number variation detection. Promoter methylation and histone modification levels were evaluated by MeDIP-qPCR and ChIP-qPCR, respectively. PCR product Sanger sequencing was carried out to detect the exon mutation rate. Twenty-two out of 38 invasive ductal carcinomas in the study (57.9%) revealed ARID1A mRNA low expression by realtime RT-PCR. The relative promoter methylation level was, significantly higher in ARID1A mRNA low expression group compared with its high expression group (p<0.001). In the low expression group, nineteen out of 22 invasive ductal carcinomas (86.4%) exhibited ARID1A promoter hypermthylation. In addition, the promoter hypermethylation was accompanied with repressive histone modification (H3K27Me3). Although five out of 38 invasive ductal carcinomas (13.2%) exhibited loss of ARID1A gene copy number by realtime PCR and nine exon novel mutations are seen from eight out of 33 invasive ductal carcinomas (24.2%), there was no statistically significant difference in both ARID1A mRNA low and high expression groups (p=0.25,and p=0.68, respectively). We demonstrate that promoter hypermethylation was the main culprit for ARID1A mRNA low expression in invasive ductal carcinomas. The influence of mutation and copy number variation on the expression were statistically insignificant at mRNA level, and were, therefore, not considered the main causes for ARID1A mRNA low expression in invasive breast cancer.
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Reduced expression levels of the death-associated protein kinase and E-cadherin are correlated with the development of esophageal squamous cell carcinoma.
Exp Ther Med
PUBLISHED: 01-11-2013
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The aim of this study was to investigate the expression levels of the death-associated protein kinase (DAPK) and E-cadherin in esophageal squamous cell carcinoma (ESCC) and their correlation with clinical and pathological factors. Immunohistochemistry [streptavidin-peroxidase (SP) method], in situ hybridization, immunoblot assays and reverse transcription-PCR (RT-PCR) were used to detect the expression of DAPK and E-cadherin in the carcinomas and the adjacent normal tissues of 76 cases of esophageal squamous carcinomas. The immunoblot assay indicated that the expression levels of DAPK and E-cadherin were decreased significantly in the ESCC tissue (P<0.05) when compared with the adjacent normal tissues. The RT-PCR results showed that the mRNA levels of DAPK and E-cadherin were reduced. The abnormal expression of DAPK was highly correlated with the invasiveness and lymphatic metastasis of the cancer. The abnormal expression of E-cadherin was highly correlated with the differentiation and lymphatic metastasis of the cancer. The decreased expression levels of DAPK and E-cadherin correlated with the development of ESCC. The combined detection of DAPK and E-cadherin proteins may be correlated with the degree of malignancy and metastatic potency of ESCC.
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A molecular beacon and graphene oxide-based fluorescent biosensor for Cu(2+) detection.
Biosens Bioelectron
PUBLISHED: 01-04-2013
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In this work, we report a "turn-on" fluorescent strategy for the direct detection of Cu(2+) in solutions using molecular beacons (MBs) and graphene oxide (GO). MBs are special single-stranded DNA and carry fluorescence sources. GO is a new nanomaterial having remarkable physical properties. In the sensing system, GO was used as an efficient fluorescence quencher upon the adsorption of MBs, which reduced the background signal and made the detection method highly sensitive. In the presence of Cu(2+), the MBs were cut into short pieces and released by the GO, leading to fluorescence restoration. The detection limit of the sensing strategy was ?50nM, which is sufficiently sensitive for practical applications. The sensing method also exhibited high selectivity in testing samples containing other metal ions. The application of the method for drinking water is demonstrated.
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Catalytic dehydration of carbohydrates on in situ exfoliatable layered niobic acid in an aqueous system under microwave irradiation.
ChemSusChem
PUBLISHED: 01-02-2013
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A simple and efficient microwave-assisted HNb(3)O(8) catalytic process is proposed for the dehydration of carbohydrates in the aqueous phase. A 5-hydroxymethylfurfural (HMF) yield of 55.9 % was achieved at a high substrate/catalyst weight ratio of 50 from a 10 wt % fructose solution, which is close to the yield achieved by homogeneous aqueous systems. The critical factor for this performance is the fast in situ exfoliation of layered HNb(3)O(8) with the aid of microwave irradiation, which leads to quasi-homogeneous catalytic behavior. Importantly, the catalytic system is also applicable for the one-pot production of HMF from di- and polysaccharides, such as inulin, through a consecutive hydrolysis-dehydration reaction. Additionally, the unique restacking feature of the exfoliated HNb(3)O(8) ensures the good reusability of the catalyst.
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Genome-wide screening for genes associated with valproic acid sensitivity in fission yeast.
PLoS ONE
PUBLISHED: 01-01-2013
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We have been studying the action mechanisms of valproic acid (VPA) in fission yeast Schizosaccharomyces pombe by developing a genetic screen for mutants that show hypersensitivity to VPA. In the present study, we performed a genome-wide screen of 3004 haploid deletion strains and confirmed 148 deletion strains to be VPA sensitive. Of the 148 strains, 93 strains also showed sensitivity to another aliphatic acids HDAC inhibitor, sodium butyrate (SB), and 55 strains showed sensitivity to VPA but not to SB. Interestingly, we found that both VPA and SB treatment induced a marked increase in the transcription activity of Atf1 in wild-type cells. However, in clr6-1, a mutant allele the clr6(+) gene encoding class I HDAC, neither VPA- nor SB induced the activation of Atf1 transcription activity. We also found that VPA, but not SB, caused an increase in cytoplasmic Ca(2+) level. We further found that the cytoplasmic Ca(2+) increase was caused by Ca(2+) influx from extracellular medium via Cch1-Yam8 channel complex. Altogether, our present study indicates that VPA and SB play similar but distinct roles in multiple physiological processes in fission yeast.
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Mid-infrared laser-driven broadband water-window supercontinuum generation from pre-excited medium.
Opt Express
PUBLISHED: 11-24-2011
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We theoretically investigate the broadband water-window supercontinuum generation from pre-excited medium with a mid-infrared pulse. We find that the wavelength scaling of the harmonic yield from near-visible (0.8 ?m) to mid-infrared (1.8 ?m) in single-atom level is ?(-2.7). Using an intense phase-stabilized few-cycle 1.6 ?m laser pulse, a broadband water window supercontinuum with bandwidth of approximately 140 eV is obtained. We also investigate the macroscopic effects and find that large initial population of the excited state leads to the high-density of free electrons, which shift the carrier-envelop phase of the driving pulse and further diminish the water-window supercontinuum generation. The highly-ionized medium also results in poor temporal and spatial properties of the attosecond pulse. Instead, small initial population of the excited state can produce well phase-matched xuv supercontinuum in water-window region and an 100-as pulse with central wavelength of 2.8 nm and pulse energy of 0.15 nJ can be filtered out.
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Laser-polarization-dependent photoelectron angular distributions from polar molecules.
Opt Express
PUBLISHED: 11-24-2011
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Photoelectron angular distributions (PADs) of oriented polar molecules in response to different polarized lasers are systematically investigated. It is found that the PADs of polar CO molecules show three distinct styles excited by linearly, elliptically and circularly polarized lasers respectively. In the case of elliptical polarization, a deep suppression is observed along the major axis and the distribution concentrates approximately along the minor axis. Additionally, it is also found that the concentrated distributions rotate clockwise as the ellipticity increases. Our investigation presents a method to manipulate the motion and angular distribution of photoelectrons by varying the polarization of the exciting pulses, and also implies the possibility to control the processes in laser-molecule interactions in future work.
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Diagnostic significance of CK19, TG, Ki67 and galectin-3 expression for papillary thyroid carcinoma in the northeastern region of China.
Diagn Pathol
PUBLISHED: 10-27-2011
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To evaluate the expression and differential diagnostic significance of CK19, TG, Ki67 and galectin-3 in papillary thyroid carcinoma (PTC) (metastatic and non metastatic), follicular adenoma and nodular goiter in patients from the northeastern part of China.
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Molecular orbital imaging via above-threshold ionization with circularly polarized pulses.
Opt Express
PUBLISHED: 09-22-2011
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Above-threshold ionization (ATI) for aligned or orientated linear molecules by circularly polarized laser pulsed is investigated. It is found that the all-round structural information of the molecular orbital is extracted with only one shot by the circularly polarized probe pulse rather than with multi-shot detections in a linearly polarized case. The obtained photoelectron momentum spectrum directly depicts the symmetry and electron distribution of the occupied molecular orbital, which results from the strong sensitivity of the ionization probability to these structural features. Our investigation indicates that the circularly polarized probe scheme would present a simple method to study the angle-dependent ionization and image the occupied electronic orbital.
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Wavelength dependence of electron localization in the laser-driven dissociation of H2(+).
Opt Express
PUBLISHED: 09-02-2011
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We theoretically investigate the laser wavelength dependence of asymmetric dissociation of H2(+). It is found that the electron localization in molecular dissociation is significantly manipulated by varying the wavelength of the driving field. Through creating a strong nuclear vibration in the laser-molecular interaction, our simulations demonstrate that the few-cycle mid-infrared pulse can effectively localize the electron at one of the dissociating nuclei with weak ionization. Moreover, we show that the observed phase-shift of the dissociation asymmetry is attributed to the different population transfers by the remaining fields after the internuclear distances reach the one-photon coupling point.
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Isolated attosecond pulse generation with the stability against the carrier-envelope phase shift and with the high-beam quality from CO gas medium.
Opt Express
PUBLISHED: 09-02-2011
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We theoretically investigate the isolated attosecond pulse generation with a 1300-nm infrared few-cycle laser pulse from the CO medium. It is found that the supercontinuum in the plateau from CO in the microscopic level can be generated for nearly all the carrier-envelop phase(CEP) of the driving pulse. The macroscopic investigation shows that when the molecular axis is parallel to the electric field, the supercontinuum can be phase-matched in broader spectral range than the antiparallel case and achieve a good beam quality with the divergence angle of 0.2 mrad, which benefits for some potential applications of ultrafast detections with high spatial and temporal resolutions.
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Macroscopic control of quantum paths in high order harmonics by a weak second harmonic field.
Opt Express
PUBLISHED: 09-02-2011
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The phase matching of quantum paths in high-order harmonic generation is investigated in a two-color laser field. Our results show that the phase-matching properties of the short and long trajectories can be modulated effectively by adding a weak second harmonic field. This scheme can not only achieve the quantum path selection, but more importantly it can achieve on-axis phase matching for both of the two trajectories simultaneously. A bright interference pattern induced by the simultaneously phase-matched two trajectories can be observed by placing a near-field on-axis filter, which has great potential for experimentally characterizing the full single-atom dipole moment.
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Broadband large-ellipticity harmonic generation with polar molecules.
Opt Express
PUBLISHED: 09-02-2011
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We investigate the polarization properties of high harmonic generation from polar molecules with a linearly polarized field. It is found that elliptically polarized harmonics are observed in a wide spectral range from the plateau to the cutoff. Further analyses show that the nonsymmetric structure of the highest occupied molecular orbital is the origin of ellipticity of the harmonics. The results provide a method for generation of large-ellipticity XUV pulses, which will benefit the application of HHG as a tool of detection in materials and biology science.
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Structural characterization of a low-molecular-weight heteropolysaccharide (glucomannan) isolated from Artemisia sphaerocephala Krasch.
Carbohydr. Res.
PUBLISHED: 08-15-2011
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Using 60% (w/v) ammonium sulfate precipitation, a heteropolysaccharide (designated 60S), with relatively low molecular weight (38.7kDa), was isolated from the seeds of Artemisiasphaerocephala Krasch. The structural properties of 60S were elucidated by partial acid hydrolysis, methylation analysis, 1D and 2D NMR spectroscopy, and MALDI-TOF-MS. The results of the partial acid hydrolysis and methylation analysis indicated that the main chain of 60S consisted of (1?4)-linked d-Manp and (1?4)-linked d-Glcp in a molar ratio of 1:1.3. Over half of the glucosyl residues in the main chain were branched at the O-6 position. The terminal sugar residues were mainly composed of T-Araf, T-Arap, T-Galp, T-GlcpA, and T-Glcp. Besides, 3-Araf and 2-Galp were also observed in comparable amounts. Based on all the aforementioned results and the data obtained by 1D and 2D NMR spectroscopy as well as MALDI-TOF-MS, a structure of 60S is proposed as follows: R could be one or some of -(3-?-Araf)(n)-(A), T-?-Galp(B), T-?-Glcp(C), T-Araf(H) or T-Arap.
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Transparent conductive films consisting of ultralarge graphene sheets produced by Langmuir-Blodgett assembly.
ACS Nano
PUBLISHED: 06-28-2011
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Monolayer graphene oxide (GO) sheets with sizes ranging from a few to ?200 ?m are synthesized based on a chemical method and are sorted out to obtain four different grades having uniform sizes. Transparent conductive films are produced using the ultralarge graphene oxide (UL-GO) sheets that are deposited layer-by-layer on a substrate using the Langmuir-Blodgett (LB) assembly technique. The density and degree of wrinkling of the UL-GO monolayers are turned from dilute, close-packed flat UL-GO to graphene oxide wrinkles (GOWs) and concentrated graphene oxide wrinkles (CGOWs) by varying the LB processing conditions. The method demonstrated here opens up a new avenue for high-yield fabrication of GOWs or CGOWs that are considered promising materials for hydrogen storage, supercapacitors, and nanomechanical devices. The films produced from UL-GO sheets with a close-packed flat structure exhibit exceptionally high electrical conductivity and transparency after thermal reduction and chemical doping treatments. A remarkable sheet resistance of ?500 ?/sq at 90% transparency is obtained, which outperforms the graphene films grown on a Ni substrate by chemical vapor deposition. The technique used in this work to produce transparent conductive UL-GO thin films is facile, inexpensive, and tunable for mass production.
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Proton pump inhibitors therapy and risk of hip fracture: a systematic review and meta-analysis.
Eur J Gastroenterol Hepatol
PUBLISHED: 06-25-2011
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Previous studies have reported inconsistent findings that proton pump inhibitors (PPIs) therapy might increase the risk of hip fracture. We investigated the association between PPIs therapy and hip fracture by a systematic review and meta-analysis.
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Spatial coherence control of xuv supercontinuum generation by two-color laser field.
Opt Express
PUBLISHED: 06-07-2011
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We investigate the spatial characteristics of xuv supercontinuum generation in the two-color laser field consisting of a fundamental and a weak second harmonic field. By optimizing the synthesized two-color field, the spatial profile of the xuv supercontinuum varies from annular-like to Gaussian-like and then the spatial quality is improved effectively, which is beneficial for its potential applications. Moreover, our calculation shows that the spatial quality of the supercontinuum is stable when the intensity of the controlling field varies in the acceptable fluctuation.
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Misuse of statistical methods in 10 leading Chinese medical journals in 1998 and 2008.
ScientificWorldJournal
PUBLISHED: 05-17-2011
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Statistical methods are vital to biomedical research. Our aim was to find out whether progress has been made in the last decade in the use of statistical methods in Chinese medical research. We reviewed 10 leading Chinese medical journals published in 1998 and in 2008. Regarding statistical methods, using a multiple t-test for multiple group comparison was the most common error in the t-test in both years, which significantly decreased in 2008. In contingency tables, no significant level adjustment for multiple comparison significantly decreased in 2008. In ANOVA, over a quarter of articles misused the method of multiple pair-wise comparison in both years, and no significant difference was seen between the two years. In the rank transformation nonparametric test, the error of using multiple pair-wise comparison for multiple group comparison became less common. Many mistakes were found in the randomised controlled trial (56.3% in 1998; 67.9% in 2008), non- randomised clinical trial (57.3%; 58.6%), basic science study (72.9%; 65.5%), case study or case series study (48.4%; 47.2%), and cross-sectional study (57.1%; 44.2%). Progress has been made in the use of statistical methods in Chinese medical journals, but much is yet to be done.
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Rosuvastatin attenuates monocrotaline-induced pulmonary hypertension via regulation of Akt/eNOS signaling and asymmetric dimethylarginine metabolism.
Eur. J. Pharmacol.
PUBLISHED: 05-17-2011
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This study was designed to investigate whether rosuvastatin could attenuate monocrotaline-induced pulmonary hypertension via regulation of Akt/eNOS signaling pathway and asymmetric dimethylarginine (ADMA) metabolism in rats. After a single-dose injection of monocrotaline (60 mg/kg), oral administration of rosuvastatin (5mg/kg) was started from day 1 to day 28 (preventive administration) or from day 15 to day 28 (therapeutic administration), or with vehicle as corresponding controls. 28 days after monocrotaline, significant pulmonary hypertension characterized by pulmonary arterial medial wall thickening, right ventricular hypertrophy and right heart failure was observed. Rosuvastatin (5mg/kg, for 14 days and 28 days) treatment significantly attenuated monocrotaline-induced pulmonary vascular remodeling, right ventricular hypertrophy and dysfunction, and normalized the down-regulated pulmonary Akt/p-Akt and eNOS/p-eNOS expressions, while increased DDAH2 expression accompanied by decreased serum level of ADMA. However expression of PRMT1 and GSK3?/p-GSK3? did not differ among all groups (all P>0.05). We concluded that rosuvastatin inhibits monocrotaline-induced pulmonary hypertension through normalization of Akt, eNOS and DDAH2 expressions, and decreasing the level of ADMA.
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Triterpenoid saponins from the seeds of Celosia argentea and their anti-inflammatory and antitumor activities.
Chem. Pharm. Bull.
PUBLISHED: 05-03-2011
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Three new triterpenoid saponins, named celosin E (1), celosin F (2) and celosin G (3), together with a known compound cristatain (4), were isolated from the seeds of Celosia argentea L. (Amaranthaceae). All the isolated compounds were obtained for the first time from this plant. The structures of new compounds were characterized on the basis of extensive NMR experiments and mass spectrometry data. The antitumor and anti-inflammatory activities of the four compounds were tested in vitro.
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Genome-wide screening for genes associated with FK506 sensitivity in fission yeast.
PLoS ONE
PUBLISHED: 04-20-2011
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We have been studying calcineurin signal transduction pathway in fission yeast Schizosaccharomyces pombe (S. pombe) by developing a genetic screen for mutants that show hypersensitivity to the immunosuppressive calcineurin inhibitor FK506 (tacrolimus). In the present study, to identify nonessential genes that are functionally related to the calcineurin signaling pathway, we performed a genome-wide screen of 3004 haploid deletion strains and confirmed 72 deletion strains to be FK506 sensitive. These 72 genes are classified into nine functional groups to include membrane trafficking (16 genes), signal transduction (10 genes), ubiquitination (8 genes), chromatin remodeling (6 genes), cytokinesis (4 genes), ribosomal protein (3 genes), RNA binding protein (3 genes), and a variety of other known functions (17 genes) or still unknown functions (5 genes) in the biological system. In our previous screening of FK506-sensitive mutants we isolated several membrane-trafficking mutants showing defective cell wall integrity. Here, we further examined the vacuolar fusion, the v-SNARE synaptobrevin Syb1 localization, and the sensitivity to the ?-glucan synthase inhibitor micafungin in these 72 FK506-sensitive strains. Results showed that 25 deletion strains exhibited abnormal vacuole fusion, 19 deletion strains exhibited Syb1 mislocalization, and 14 deletion strains exhibited both abnormal vacuole fusion and Syb1 mislocalization, while 42 deletion strains showed both normal vacuole fusion and Syb1 localization. Likewise, 16 deletion strains showed sensitivity to micafungin. Altogether, our present study indicates that calcineurin mediates a plethora of physiological processes in fission yeast, and that calcineurin is extensively involved in cross-talk between signaling pathways.
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Dual-chirped optical parametric amplification for generating few hundred mJ infrared pulses.
Opt Express
PUBLISHED: 04-20-2011
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An ultrafast high-power infrared pulse source employing a dual-chirped optical parametric amplification (DC-OPA) scheme based on a Ti:sapphire pump laser system is theoretically investigated. By chirping both pump and seed pulses in an optimized way, high-energy pump pulses can be utilized for a DC-OPA process without exceeding the damage threshold of BBO crystals, and broadband signal and idler pulses at 1.4 ?m and 1.87 ?m can be generated with a total conversion efficiency approaching 40%. Furthermore, few-cycle idler pulses with a passively stabilized carrier-envelope phase (CEP) can be generated by the difference frequency generation process in a collinear configuration. DC-OPA, a BBO-OPA scheme pumped by a Ti:sapphire laser, is efficient and scalable in output energy of the infrared pulses, which provides us with the design parameters of an ultrafast infrared laser system with an energy up to a few hundred mJ.
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Effects of stage, intercalant species and expansion technique on exfoliation of graphite intercalation compound into graphene sheets.
J Nanosci Nanotechnol
PUBLISHED: 04-02-2011
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Graphite is composed of a series of stacked parallel graphene layers bonded by weak van der Waals forces. Although the weak interactions that hold the graphene sheets together allow them to slide readily over each other, the numerous weak bonds make it difficult to separate the sheets. A graphene sheet is a two-dimensional platelet consisting of a few graphene layers with an overall thickness in nanometer scale. Graphene sheets can be obtained from intercalation and subsequent exfoliation of graphite. To realize the expansion and exfoliation behaviors of graphite, graphite intercalation compound (GIC) is produced using an electrochemical method and three important factors, namely stage structure of GIC, intercalant species and expansion techniques, are taken into account. Graphene sheets produced from a lower stage FeCl3-GIC display the best exfoliation behavior in terms of specific surface area, total pore volume and expansion volume. Microwave irradiation gives rise to a more explosive expansion than heating in a furnace.
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Molecular engineering and theoretical investigation of organic sensitizers based on indoline dyes for quasi-solid state dye-sensitized solar cells.
Phys Chem Chem Phys
PUBLISHED: 04-01-2011
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Novel indoline dyes, I-1-I-4, with structural modification of ?-linker group in the D-?-A system have been synthesized and fully characterized. Molecular engineering through expanding the ?-linker segment has been performed. The ground and excited state properties of the dyes have been studied by means of density functional theory (DFT) and time-dependent DFT (TD-DFT). Larger ?-conjugation linkers would lead to broader spectral response and higher molar extinction coefficient but would decrease dye-loaded amount on TiO(2) electrode and LUMO level. While applied in DSSCs, the variation trends in short-circuit current density (J(sc)) and open-circuit voltage (V(oc)) were observed to be opposite to each other. The internal reasons were studied by experimental data and theoretical calculations in detail. Notably, I-2 showed comparable photocurrent values with liquid and quasi-solid state electrolyte, which suggested through molecular engineering of organic sensitizers the dilemma between optical absorption and charge diffusion lengths can be balanced well. Through studies of photophysical, electrochemical, and theoretical calculation results, the internal relations between chemical structure and efficiency have been revealed, which serve to enhance our knowledge regarding design and optimization of new sensitizers for quasi-solid state DSSCs, providing a powerful strategy for prediction of photovoltaic performances.
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Hospital-based study of the economic burden associated with rotavirus diarrhea in eastern China.
Vaccine
PUBLISHED: 03-18-2011
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Rotavirus infection is one of the most common causes of severe diarrhea in China. To evaluate the economic burden associated with rotavirus infection of children in China, we combined data on the disease burden of rotavirus-associated costs for samples comprising 832 outpatients and 604 inpatients from five seaside cities. The average social costs and direct medical costs for rotavirus-associated admissions were calculated to be US $61.64 and US $40.73 for outpatients, and US $684.15 and US $559.48 for inpatients, respectively, from October 1, 2006 to December 1, 2007. On average, the private cost ranged from US $54.64 for outpatients to US $454.24 for inpatients when children suffered from rotavirus infection. Accordingly, this cost accounted for 35.19-293% of the monthly income of an unskilled or service worker. We estimated that the annual number of children with rotavirus diarrhea was 12.10 million. Consequently, the total annual direct cost, total annual social cost, and total annual private cost were US $271.4 million, US $365.0 million, and US $290.0 million, respectively. Furthermore, rotavirus diarrhea affected childrens behavior and emotions, which had a great influence on the caretakers quality of life. These data indicate the potential requirement for a safe and effective rotavirus vaccine to reduce the economic burden associated with rotavirus disease.
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Intense isolated attosecond pulse generation in pre-excited medium.
Opt Express
PUBLISHED: 03-04-2011
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We present a theoretical study of isolated attosecond pulse generation in pre-excited medium driven by an intense few-cycle laser pulse. We show that the generation of the macroscopic xuv supercontinuum is governed by the initial population of the excited state. Large initial population of the excited state leads to the high density of the free electrons in the media and strongly changes macroscopic properties of the driving pulse and the supercontinuum, and diminishes the isolated attosecond pulse generation. Instead, small initial population of 5% in the pre-excited media subjected to the few-cycle driving pulse can produce well phase-matched xuv supercontinuum, and a pure intense isolated attosecond pulse with the pulse duration of approximately 150 as and the pulse energy up to 0.5 nJ is directly obtained.
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Tributyltin chloride-induced immunotoxicity and thymocyte apoptosis are related to abnormal Fas expression.
Int J Hyg Environ Health
PUBLISHED: 01-27-2011
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Tributyltin chloride (TBTC), a characteristic organotin compound, is widely used as an agricultural pesticide, as a stabiliser for polyvinyl-chloride plastics and in antifouling paints for ship hulls. Organotin compounds are known to produce toxicity in the immune system, but the mechanism underlying this immunotoxicity remains unclear. In this study, we evaluated the immunotoxic effect of TBTC on the acquired immune response, and we investigated the involvement of thymocyte apoptosis and Fas expression in the observed immunotoxicity of TBTC. Mice were randomly assigned to four groups (10 mice per group) and treated with TBTC at doses of 0, 0.5, 4 and 20 mg/kg by oral gavage for 28 days. Following TBTC administration, animals were sacrificed, and morphologic changes in the thymus and spleen were assessed. Atrophy in both the thymus and spleen was observed in all groups treated with TBTC, and the relative organ weight in the highest TBTC group (20 mg/kg) was significantly lower than that observed in the control group. We also conducted assays to assess the cellular and humoral functional responses such as plaque-forming cell assay (PFC), lymphocyte proliferation test and delayed-type hypersensitivity (DTH) response to SRBC. Our results indicate that at doses of 4 mg/kg and 20 mg/kg, TBTC could significantly suppress both the humoral and cellular immune responses when compared to the control group (p<0.05). In addition, immunohistochemical staining and flow cytometry analysis were carried out to measure the expression of Fas and thymocyte apoptosis, respectively. We observed a dose-dependent increase in thymocyte apoptosis and that Fas expression in the TBTC-treated groups (4 mg/kg and 20 mg/kg) was significantly enhanced when compared to the control group. Correlation analysis demonstrated a positive linear correlation between apoptosis and Fas expression, indicating that TBTC-induced thymocyte apoptosis may be mediated by Fas expression. Taken together, our data clearly demonstrate that TBTC-induced immunotoxicity is associated with thymocyte apoptosis and that this process is mediated by the Fas pathway.
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Two-center interference in high-order harmonic generation from heteronuclear diatomic molecules.
Opt Express
PUBLISHED: 01-26-2011
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Two-center interference for heteronuclear diatomic molecules (HeDM) is investigated. The minimum in the high-order harmonic spectrum, as a consequence of the destructive interference, is shifted to lower harmonic orders compared with that in a homonuclear case. This phenomenon is explained by performing phase analysis. It is found that, for an HeDM, the high harmonic spectrum contains information not only on the internuclear separation but also on the properties of the two separate centers, which implies the potential application of estimating the asymmetry of molecules and judging the linear combination of atomic orbitals (LCAO) for the highest occupied molecular orbital (HOMO). Moreover, the possibility to monitor the evolution of HOMO itself in molecular dynamics is also promised.
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Molecular dynamics study of the effect of chemical functionalization on the elastic properties of graphene sheets.
J Nanosci Nanotechnol
PUBLISHED: 12-09-2010
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In this study, the effects of chemical functionalization on the elastic properties of graphene sheets are investigated by using molecular dynamics (MD) and molecular mechanics (MM) simulations. The influences of the degree of functionalization, which is defined as the ratio of the number of the total sp3-hybridized atoms to the number of the total carbon atoms of the graphene sheet, the chirality of graphene sheets, the molecular structure and molecular weight of functional groups on Youngs modulus are studied. The dependence of shear modulus and wrinkling properties on the functional groups are also investigated. The simulation results indicate that Youngs modulus depends strongly on the degree of functionalization and the molecular structure of the functional groups, while the effects of chirality of the graphene sheets and the molecular weight of the functional groups are negligible. The chemical functionalization also reduces the shear modulus and critical strain, beyond which the wrinkling instability occurs.
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