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Find video protocols related to scientific articles indexed in Pubmed.
Characterization of evolution of mode coupling in a graded-index polymer optical fiber by using Brillouin optical time-domain analysis.
Opt Express
PUBLISHED: 11-18-2014
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A narrow bandwidth (2GHz) ?-phase-shift flattop fiber Bragg grating (FBG) is proposed to achieve Brillouin optical time-domain analysis (BOTDA) for perfluorinated graded-index polymer optical fibers (GI-POFs) for the first time to best of our knowledge. Using the technique of BOTDA, we explore the evolution of mode coupling in perfluorinated GI-POFs by analyzing the Brillouin frequency shift (BFS) variation along the whole fiber, and compare them with that of silica graded index multimode fibers (GI-MMFs). The characteristics of mode coupling of GI-POFs and GI-MMFs were also investigated in terms of the speckle patterns at the output face of the two fibers. The results show that compared with silica GI-MMFs, GI-POFs exhibit more efficient mode coupling and the excellent ablility of mode scrambling regardless of alignment conditions.
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Internal and near-surface electromagnetic fields for a dielectric spheroid illuminated by a zero-order Bessel beam.
J Opt Soc Am A Opt Image Sci Vis
PUBLISHED: 11-18-2014
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Within the framework of generalized Lorenz-Mie theory, scattering from a homogeneous spheroidal particle illuminated by an on-axis zero-order Bessel beam is formulated analytically, with special attention paid to the investigation of internal and near-surface fields. Numerical results concerning the spatial distributions of internal and near-surface fields are presented for various parameter values, such as the half-cone angle of the incident zero-order Bessel beam, the major axis, the minor axis, and the refractive index of the spheroid. The study of internal and near-surface field distributions will contribute to the understanding of Bessel beam scattering by nonspherical particles with sizes close to the incident wavelength.
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Genetic Analysis of Zebrafish Gonadotropin (FSH and LH) Functions by TALEN-mediated Gene Disruption.
Mol. Endocrinol.
PUBLISHED: 11-15-2014
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Vertebrate reproduction is controlled by two gonadotropins (FSH and LH) from the pituitary. Despite numerous studies on FSH and LH in fish species, their functions in reproduction still remain poorly defined. This is partly due to the lack of powerful genetic approaches for functional studies in adult fish. This situation is now changing with the emergence of genome-editing technologies, especially TALEN and CRISPR/Cas9. In this study, we deleted the hormone-specific ? genes of both FSH and LH in the zebrafish using TALEN. This was followed by phenotype analysis for key reproductive events, including gonadal differentiation, puberty onset, gametogenesis, final maturation, and fertility. FSH-deficient zebrafish (fshb(-/-)) were surprisingly fertile in both sexes; however, the development of both ovary and testis was significantly delayed. In contrast, LH-deficient zebrafish (lhb(-/-)) showed normal gonadal growth, but the females failed to spawn and were therefore infertile. Using previtellogenic (PV) follicles as the marker, we observed a significant delay of puberty onset in fshb mutant but not lhb mutant females. Interestingly, FSH seemed to play a role in maintaining female status as we repeatedly observed sexual reversal in fshb mutant. Neither fshb nor lhb mutation alone seemed to affect gonadal differentiation; however, double mutation of the two genes led to all males although the development of the testis was significantly delayed. In summary, our data confirmed some well-known functions of FSH and LH in fish while also providing evidence for novel functions, which would be difficult to reveal using traditional biochemical and physiological approaches.
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A low cycle fatigue test device for micro-cantilevers based on self-excited vibration principle.
Rev Sci Instrum
PUBLISHED: 11-03-2014
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This paper reports a low-cycle fatigue test device for micro-cantilevers, which are widely used in micro scale structures. The working principle of the device is based on the phenomenon that a micro-cantilever can be set into self-excited vibration between two electrodes under DC voltage. Compared with previous devices, this simple device can produce large strain amplitude on non-notched specimens, and allows a batch of specimens to be tested simultaneously. Forty-two micro-cantilever specimens were tested and their fatigue fracture surfaces exhibit typical low cycle fatigue characteristics. As such, the device is very attractive for future fatigue investigation for micro scale structures.
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Enhanced spectral response of an AlGaN-based solar-blind ultraviolet photodetector with Al nanoparticles.
Opt Express
PUBLISHED: 10-17-2014
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An enhanced spectral response was realized in an AlGaN-based solar-blind ultraviolet (SB-UV) detector using aluminum (Al) nanoparticles (NPs) of 20-60 nm. The peak responsivity of the detector (about 288 nm) with 60 nm Al NPs is more than two times greater than that of a detector without Al NPs under a 5-V bias, reaching 0.288 A/W. To confirm the enhancement mechanism of the Al NPs, extinction spectra were simulated using time-domain and frequency-domain finite-element methods. The calculation results show that the dipole surface plasmon resonance wavelength of the Al NPs is localized near the peak responsivity position of AlGaN-based SB-UV detectors. Thus, the improvement in the detectors can be ascribed to the localized surface plasmon resonance effect of the Al NPs. The localized electric field enhancement and related scattering effect result in the generation of more electron-hole pairs and thus a higher responsivity. In addition, the dark current of AlGaN-based SB-UV detectors does not increase after the deposition of Al nanoparticles. The results presented here is promising for applications of AlGaN-based SB-UV detectors.
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[Screening of common deafness gene mutations in 17 000 Chinese newborns from Chengdu based on microarray analysis].
Zhonghua Yi Xue Yi Chuan Xue Za Zhi
PUBLISHED: 10-10-2014
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To achieve early diagnosis for inheritable hearing loss and determine carrier rate of deafness causing gene mutations in order to provide information for premarital, prenatal and postnatal genetic counseling.
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Optimized performances of tetrapod-like ZnO nanostructures for a triode structure field emission planar light source.
Nanoscale
PUBLISHED: 10-01-2014
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Tetrapod-like ZnO (T-ZnO) nanostructures were synthesized by a simple vapor phase oxidation method without any catalysts or additives. We optimized the performances of T-ZnO nanostructures by adjusting the partial pressure of Zn vapour in the total pressure of the quartz chamber and obtained T-ZnO nanostructure materials of high purity, uniform morphology and size and high aspect ratio with a low turn-on electric field of 2.75 V ?m(-1), a large field enhancement factor of 3410 and good field emission stability for more than 70 hour continuous emission. Besides, based on the optimized T-ZnO, we developed metal grid mask-assisted water-based electrostatic spraying technology, and fabricated a large-scale, pollution-free, hole-shaped array T-ZnO nanostructure cathode used in a triode structure field emission planar light source. The controllable performances of the triode device were intensively investigated and the results showed that the triode device uniformly illuminated with a luminous intensity as high as 8000 cd m(-2) under the conditions of 200 V grid voltage and 3300 V anode voltage. The research in this paper will benefit the development of a high performance planar light source based on T-ZnO nanostructures.
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[Digitalization study of sonotubometry device].
Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi
PUBLISHED: 09-23-2014
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Sonotubometry is wildly used in developed countries, offers a easy, versatile and objective way to assess the function of Eustachian tube. The objectives of this study are to develop a low-cost digitalized device.
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[Genetics and pedigree analysis of primary carnitine deficiency cardiomyopathy in 6 cases].
Zhonghua Er Ke Za Zhi
PUBLISHED: 09-17-2014
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To investigate the mutation and background of SLC22A5 in 6 patients with primary carnitine deficiency (PCD) who only presented as cardiomyopathy.
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Differential microRNA expression profile comparison between epidermal stem cells and differentiated keratinocytes.
Mol Med Rep
PUBLISHED: 09-12-2014
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The aim of the current study was to analyze the differential microRNA (miRNA) expression profiles of human epidermal stem cells (ESCs) and differentiated keratinocytes. Enzyme digestion was used in combination with rapid adhesion to collagen IV to isolate primary human ESCs and differentiated keratinocytes, from which total RNA was extracted. Fluorescence labeling, microarray hybridization and differential expression analyses were performed. Reverse transcription quantitative polymerase chain reaction (RT?qPCR) was performed to validate the reliability of the microarray results and predict the target genes of the differentially expressed miRNAs. A total of 25 miRNAs, including hsa?miR?197?5p, hsa?miR?125b?5p and hsa?miR?376a?3p, were upregulated, whereas 166 miRNAs, including hsa?miR?29b?3p, hsa?miR?203 and hsa?miR?34a?3p, were downregulated in the human ESCs compared with the expression in differentiated keratinocytes. RT?qPCR results confirmed the upregulation of hsa?miR?197?5p and the downregulation of hsa?miR?29b?3p, which were consistent with the microarray results. miRNA target prediction indicated that the miRNA expression levels correlated with cell proliferation, differentiation, apoptosis and senescence. Expression levels of miRNAs significantly differed between human ESCs and differentiated keratinocytes. This finding may be attributed to their biological characteristics, such as proliferative behavior and differentiation abilities.
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[Effect of perioperative treatment with ambroxol on lung cancer patients after video-assisted thoracic surgery lobectomy].
Zhong Nan Da Xue Xue Bao Yi Xue Ban
PUBLISHED: 09-10-2014
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To evaluate the influence of perioperative intravenous administration of ambroxol on pulmonary function, postoperative complications, postoperative hospital stay, and cost after video-assisted thoracic surgery lobectomy for lung cancer.
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Hypoxia-inducible factor 1? mediates neuroprotection of hypoxic postconditioning against global cerebral ischemia.
J. Neuropathol. Exp. Neurol.
PUBLISHED: 09-06-2014
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Hypoxia administered after transient global cerebral ischemia (tGCI) has been shown to induce neuroprotection in adult rats, but the underlying mechanisms for this protection are unclear. Here, we tested the hypothesis that hypoxic postconditioning (HPC) induces neuroprotection through upregulation of hypoxia-inducible factor 1? (HIF-1?) and vascular endothelial growth factor (VEGF), and that this involves phosphatidylinositol-3-kinase (PI3K), p38 mitogen-activated protein kinase (p38 MAPK), and mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK) pathways. The expression of HIF-1?, VEGF, and cleaved caspase-9 were determined by immunohistochemistry and Western blot. As pharmacologic interventions, the HIF-1? inhibitor 2-methoxyestradiol (2ME2), PI3K inhibitor LY294002, p38 MAPK inhibitor SB203580, and MEK inhibitor U0126 were administered before HPC or after tGCI. We found that HPC maintained the higher expression of HIF-1? and VEGF and decreased cleaved caspase-9 levels in CA1 after tGCI. These effects were reversed by 2ME2 administered before HPC, and the neuroprotection of HPC was abolished. LY294002 and SB203580 decreased the expression of HIF-1? and VEGF after HPC, whereas U0126 increased HIF-1? and VEGF after tGCI. These findings suggested that HIF-1? exerts neuroprotection induced by HPC against tGCI through VEGF upregulation and cleaved caspase-9 downregulation, and that the PI3K, p38 MAPK, and MEK pathways are involved in the regulation of HIF-1? and VEGF.
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Multimodal nonlinear optical microscopic imaging provides new insights into acetowhitening mechanisms in live mammalian cells without labeling.
Biomed Opt Express
PUBLISHED: 09-01-2014
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We developed a multimodal nonlinear optical microscopy imaging (e.g., third-harmonic generation (THG) and two-photon excited fluorescence (TPEF)) platform based on a femtosecond laser pumped photonic crystal fiber to investigate the acetowhitening phenomenon induced by acetic acid in live mammalian cells without labeling. After treated by acetic acid with concentrations of higher than 0.2%, THG images show that light scattering is remarkably increased inside the nucleus and cytoplasm in cells. Co-localized TPEF and THG imaging on tryptophan and NADH in cells indicates that the change of scattering property is largely originating from the morphological change of metabolic proteins induced by acetic acids. Further TPEF imaging on NADH and FAD in cells confirms that this change is irreversible when acetic acid concentration is higher than 1.2%. These subcellular-level THG/TPEF imaging results reveal that the acetowhitening phenomenon is highly related with proteins involved in metabolic pathways in the nucleus and cytoplasm in live cells.
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microRNA?22 acts as a metastasis suppressor by targeting metadherin in gastric cancer.
Mol Med Rep
PUBLISHED: 08-29-2014
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microRNA (miR)?22 has been reported to be downregulated in hepatocellular, lung, colorectal, ovarian and breast cancer, acting as a tumor suppressor. The present study investigated the potential effects of miR?22 on gastric cancer invasion and metastasis and the molecular mechanism. miR?22 expression was examined in tumor tissues of in 89 gastric cancer patients by in situ hybridization (ISH) analysis. Additionally, the association between miR?22 levels and clinicopathological parameters was analyzed. A luciferase assay was conducted for target identification. The ability of invasion and metastasis of gastric cancer cells in vitro and in vivo was evaluated by cell migration and invasion assays and in a xenograft model. The results showed that miR?22 was downregulated in the gastric cancer specimens and significantly correlated with the advanced clinical stage and lymph node metastasis. In addition, metadherin (MTDH) was shown to be a direct target of miR?22 and the expression of MTDH was inversely correlated with miR?22 expression in gastric cancer. Ectopic expression of miR?22 suppressed cell invasion and metastasis in vitro and in vivo. The present study suggested that miR?22 may be a valuable prognostic factor in gastric cancer. miR?22 inhibited gastric cancer cell invasion and metastasis by directly targeting MTDH. The novel miR?22/MTDH link confirmed in the present study provided a novel, potential therapeutic target for the treatment of gastric cancer.
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Mechanistic and dynamic insights into ligand encapsulation by helical arylamide foldamers.
Phys Chem Chem Phys
PUBLISHED: 08-26-2014
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Molecular capsules have been extensively used in catalysis, drug delivery, molecular recognition and protection of ligands from degradation. Novel "apple peel" shaped helical arylamide capsules have been experimentally pursued due to their flexible nature and designability. They were found to encapsulate a variety of small molecules. The apple peel shape of the capsules led to a hypothesis that binding and release of ligands involve partial unfolding. However, the exact mechanism is unknown. Using molecular dynamics simulations with our new aryl-amide force field parameters, we identify two low energy barrier binding/release mechanisms, in which the capsule's helical structure is either minimally disturbed or restored quickly (within 100 ps). Furthermore, we determine the effects of ligand sizes, their chemical nature (hydrogen bonding capabilities), and solvents on binding modes and stabilities. Our findings not only support experimental observations but also provide underlying principles that allow for rational design of foldamer capsules.
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Near-infrared Raman spectroscopy for assessing biochemical changes of cervical tissue associated with precarcinogenic transformation.
Analyst
PUBLISHED: 08-21-2014
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Raman spectroscopy measures the inelastically scattered light from tissue that is capable of identifying native tissue biochemical constituents and their changes associated with disease transformation. This study aims to characterize the Raman spectroscopic properties of cervical tissue associated with the multi-stage progression of cervical precarcinogenic sequence. A rapid-acquisition fiber-optic near-infrared (NIR) Raman diagnostic system was employed for tissue Raman spectral measurements at 785 nm excitation. A total of 68 Raman spectra (23 benign, 29 low-grade squamous intraepithelial lesions (LSIL) and 16 high grade squamous intraepithelial lesions (HSIL)) were measured from 25 cervical tissue biopsy specimens, as confirmed by colposcopy-histopathology. The semi-quantitative biochemical modeling based on the major biochemicals (i.e., DNA, proteins (histone, collagen), lipid (triolein) and carbohydrates (glycogen)) in cervical tissue uncovers the stepwise accumulation of biomolecular changes associated with progressive cervical precarcinogenesis. Multi-class partial least squares-discriminant analysis (PLS-DA) together with leave-one tissue site-out, cross-validation yielded the diagnostic sensitivities of 95.7%, 82.8% and 81.3%; specificities of 100.0%, 92.3% and 88.5%,for discrimination among benign, LSIL and HSIL cervical tissues, respectively. This work suggests that the Raman spectral biomarkers have identified the potential to be used for monitoring the multi-stage cervical precarcinogenesis, forming the foundation of applying NIR Raman spectroscopy for the early diagnosis of cervical precancer in vivo at the molecular level.
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Ontological reconstruction of the clinical terminology of traditional Chinese medicine.
Front Med
PUBLISHED: 08-16-2014
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This study proposes the ontological reconstruction of the current clinical terminology of traditional Chinese medicine (TCM). It also provides an overview of preliminary work related to the said reconstruction, including the ontology-based analysis of TCM clinical terminology. We conclude that the ontological reconstruction of TCM clinical terminology provides a proper translation from the idealized organizational model to real-world implementation and to a formalized, shared, and knowledge-based framework.
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Long-Term Effects of Continuous Positive Airway Pressure on Blood Pressure and Prognosis in Hypertensive Patients with Coronary Heart Disease and Obstructive Sleep Apnea: A Randomized Controlled Trial.
Am. J. Hypertens.
PUBLISHED: 08-14-2014
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Obstructive sleep apnea (OSA) can result in hypertension and significantly increase cardiovascular morbidity and mortality. There are few reports on the long-term effects of continuous positive airway pressure (CPAP) on blood pressure in patients with uncontrolled hypertension with coronary heart disease (CHD) and OSA.
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An intensity ratio of interlocking loops determines circadian period length.
Nucleic Acids Res.
PUBLISHED: 08-13-2014
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Circadian clocks allow organisms to orchestrate the daily rhythms in physiology and behaviors, and disruption of circadian rhythmicity can profoundly affect fitness. The mammalian circadian oscillator consists of a negative primary feedback loop and is associated with some 'auxiliary' loops. This raises the questions of how these interlocking loops coordinate to regulate the period and maintain its robustness. Here, we focused on the REV-ERB?/Cry1 auxiliary loop, consisting of Rev-Erb?/ROR-binding elements (RORE) mediated Cry1 transcription, coordinates with the negative primary feedback loop to modulate the mammalian circadian period. The silicon simulation revealed an unexpected rule: the intensity ratio of the primary loop to the auxiliary loop is inversely related to the period length, even when post-translational feedback is fixed. Then we measured the mRNA levels from two loops in 10-mutant mice and observed the similar monotonic relationship. Additionally, our simulation and the experimental results in human osteosarcoma cells suggest that a coupling effect between the numerator and denominator of this intensity ratio ensures the robustness of circadian period and, therefore, provides an efficient means of correcting circadian disorders. This ratio rule highlights the contribution of the transcriptional architecture to the period dynamics and might be helpful in the construction of synthetic oscillators.
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Genotoxicity of tri- and hexavalent chromium compounds in vivo and their modes of action on DNA damage in vitro.
PLoS ONE
PUBLISHED: 08-11-2014
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Chromium occurs mostly in tri- and hexavalent states in the environment. Hexavalent chromium [Cr(VI)] compounds are extensively used in diverse industries, and trivalent chromium [Cr(III)] salts are used as micronutrients and dietary supplements. In the present work, we report that they both induce genetic mutations in yeast cells. They both also cause DNA damage in both yeast and Jurkat cells and the effect of Cr(III) is greater than that of Cr(VI). We further show that Cr(III) and Cr(VI) cause DNA damage through different mechanisms. Cr(VI) intercalates DNA and Cr(III) interferes base pair stacking. Based on our results, we conclude that Cr(III) can directly cause genotoxicity in vivo.
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Expression of sulfur uptake assimilation-related genes in response to cadmium, bensulfuron-methyl and their co-contamination in rice roots.
J Environ Sci (China)
PUBLISHED: 08-01-2014
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The responses of sulfur (S) uptake assimilation-related genes' expression in roots of two rice cultivars to cadmium (Cd), bensulfuron-methyl (BSM) and their co-contamination (Cd+BSM) were investigated by gene-chip microarray analysis and quantitative real-time PCR (QRT-PCR) technology. Treatments of Cd and Cd+BSM induced expression of sulfate transporter and permease genes, and promoted sulfate uptake in rice roots. Cd+BSM could alleviate Cd toxicity to cv. Fengmeizhan seedlings, probably due to Cd+BSM promoting greater S absorption by seedlings. Cd and Cd+BSM induced expression of sulfate assimilation-related genes, and thus activated the sulfur assimilation pathway. Cd and Cd+BSM induced expression of phytochelatin synthase and metallothionein genes, and induced expression of glutathione S-transferases (GSTs), glutathione synthase (GS) and S-containing antioxidation enzyme genes, which detoxified Cd(2+). It is suggested that (to cope with the toxicity of Cd, BSM and their co-contamination) the S uptake and assimilation pathway was activated in rice roots by increased expression of related genes, thus enhancing the supply of organic S for synthesis of Cd or BSM resistance-related substances.
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Control for a synchronization-desynchronization switch.
Phys Rev E Stat Nonlin Soft Matter Phys
PUBLISHED: 07-28-2014
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How to freely enhance or suppress synchronization of networked dynamical systems is of great importance in many disciplines. A unified precise control method for a synchronization-desynchronization switch, called the pull-push control method, is suggested. Namely, synchronization can be achieved when the original systems are desynchronous by pulling (or protecting) one node or a certain subset of nodes, whereas desynchronization can be accomplished when the systems are already synchronous by pushing (or kicking) one node or a certain subset of nodes. With this method, the controlled nodes should be chosen by the generalized eigenvector centrality of the critical synchronization mode of the Laplacian matrix. Compared with existing control methods for synchronization, it displays high efficiency, flexibility, and precision as well.
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Nucleotide excision repair gene ERCC1 19007T>C polymorphism contributes to lung cancer susceptibility: a meta-analysis.
Genet Test Mol Biomarkers
PUBLISHED: 07-22-2014
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Association studies of ERCC1 19007T>C polymorphism and lung cancer have yielded inconsistent results, possibly because single studies often lack sufficient statistical power.
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Phase matching for noncollinear Brillouin amplification based on controlling of frequency shift of Stokes seed.
Opt Lett
PUBLISHED: 07-01-2014
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A method to compensate phase detuning, which will lead to the low efficiency in noncollinear Brillouin amplification by controlling the frequency shift of Stokes seed, is proposed. The efficiency of noncollinear Brillouin amplification can be sustained at the level of collinear Brillouin amplification for a large crossing angle. For crossing angles between Stokes and pump of 20° and 35°, the Brillouin gain coefficient is improved 1.24 and 4.93 times, accordingly.
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Sub-MHz ultrahigh-resolution optical spectrometry based on Brillouin dynamic gratings.
Opt Lett
PUBLISHED: 07-01-2014
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We propose and demonstrate an ultrahigh-resolution optical spectrometry based on Brillouin dynamic gratings (BDGs). Taking advantage of creating a long grating in an optical fiber, an ultra-narrow bandwidth optical filter is realized by operating a BDG in a long single-mode fiber (SMF), and the optical spectrometry is performed by sweeping the center wavelength of the BDG-based filter through a swept-tuned laser. The BDG-based optical spectrometry features ultrahigh resolution, large wavelength coverage, and a simple direction-detection scheme. In the experiment, a 4 fm (0.5 MHz) spectral resolution is achieved by operating a BDG in a 400 m SMF, and the wavelength coverage can be readily extended to C+L bands with a commercial tunable laser.
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A cytosolic glucose-6-phosphate dehydrogenase gene, ScG6PDH, plays a positive role in response to various abiotic stresses in sugarcane.
Sci Rep
PUBLISHED: 06-10-2014
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As one of the key enzymes in the oxidative pentose phosphate pathway, glucose-6-phosphate dehydrogenase (G6PDH) plays a role in response to abiotic stresses and pathogenesis. Here, a full-length cDNA was obtained, designed as ScG6PDH from sugarcane. The ScG6PDH gene is 1,646?bp long with a 1,524-bp long ORF encoding 507 amino acid residues. Analysis of a phylogenetic tree indicated that this gene is a member of the cytosolic G6PDH gene family, which is consistent with results from a subcellular localization experiment. Based on a real-time quantitative RT-PCR performed under salt, drought, heavy metal (CdCl2) and low temperature (4°C) treatments, the transcription levels of the ScG6PDH gene were higher compared with transcription levels where these treatments were not imposed, suggesting a positive response of this gene to these environmental stresses. Furthermore, G6PDH activity was stimulated under 4°C, CdCl2, NaCl and PEG treatments, but the increments varied with treatment and sampling time, implying positive response to abiotic stresses, similar to the transcript of the G6PDH gene. Ion conductivity measurements and a histochemical assay provided indirect evidence of the involvement of the ScG6PDH gene in defense reactions to the above-mentioned abiotic stresses.
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Modified arterioportal shunting in radical resection of hilar cholangiocarcinoma.
Hepatogastroenterology
PUBLISHED: 06-05-2014
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The resection and reconstruction of hepatic artery is often required in radical surgery for hilar cholangiocarcinoma. In this study, we reported our experience in performing the arterioportal shunting with restriction of the arterial caliber as an alternative for the arterial reconstruction on the basis of our experiment when reconstruction of hepatic artery is impossible.
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The pharmacokinetic properties of bifenthrin in the rat following multiple routes of exposure.
Pest Manag. Sci.
PUBLISHED: 05-23-2014
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Pyrethroids generally have relatively low oral toxicity but variable inhalation toxicity. The pharmacokinetics of bifenthrin in the rat after oral, inhalation and intravenous administration is described. Pyrethroid acute toxicity via oral and inhalation routes is also presented.
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The compensatory enrichment of sphingosine -1- phosphate harbored on glycated high-density lipoprotein restores endothelial protective function in type 2 diabetes mellitus.
Cardiovasc Diabetol
PUBLISHED: 04-07-2014
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Glycation of high-density lipoprotein (HDL) decreases its ability to induce cyclooxygenase-2 (COX-2) expression and prostacyclin I-2 (PGI-2) release in endothelial cells. Whether lipid content of HDL, especially sphingosine-1-phosphate (S1P), plays any specific role in restoring the protective function of HDL in type 2 diabetes mellitus (T2DM) is still unknown.
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PER1 phosphorylation specifies feeding rhythm in mice.
Cell Rep
PUBLISHED: 03-25-2014
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Organization of circadian behavior, physiology, and metabolism is important for human health. An S662G mutation in hPER2 has been linked to familial advanced sleep-phase syndrome (FASPS). Although the paralogous phosphorylation site S714 in PER1 is conserved in mice, its specific function in circadian organization remains unknown. Here, we find that the PER1S714G mutation accelerates the molecular feedback loop. Furthermore, hPER1S714G mice, but not hPER2S662G mice, exhibit peak time of food intake that is several hours before daily energy expenditure peaks. Both the advanced feeding behavior and the accelerated clock disrupt the phase of expression of several key metabolic regulators in the liver and adipose tissue. Consequently, hPER1S714G mice rapidly develop obesity on a high-fat diet. Our studies demonstrate that PER1 and PER2 are linked to different downstream pathways and that PER1 maintains coherence between the circadian clock and energy metabolism.
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Effect of oleic acid on the levels of eight metal ions in human hepatoma SMMC-7721 cells.
Biol Trace Elem Res
PUBLISHED: 03-17-2014
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Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease. Its incidence is rising worldwide. However, no specific therapy has been shown to be effective in its treatment. In the present study, the in vitro NAFLD model was established in human SMMC-7721 cells by using oleic acid (OA). Then, content changes of eight cations, including sodium, magnesium, potassium, calcium, iron, copper, zinc, and manganese, were investigated in the experimental model. The results showed that OA induced a decrease in magnesium level, while an increase in iron one. Additionally, the supplementation of magnesium in the cell culture model was studied. It showed that magnesium ameliorated lipid accumulation induced by OA. Our results suggest that magnesium could decrease the risk of NAFLD and be used as a promising candidate for the treatment of NAFLD.
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Preoperative total cholesterol predicts postoperative outcomes after partial hepatectomy in patients with chronic hepatitis B- or C-related hepatocellular carcinoma.
Surgery
PUBLISHED: 02-27-2014
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Total cholesterol (TC) can reflect the degree of liver damage in patients with chronic hepatitis B or C; its role in evaluating liver functional reserve and predicting postoperative complications remains unknown.
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Selection of suitable endogenous reference genes for relative copy number detection in sugarcane.
Int J Mol Sci
PUBLISHED: 02-19-2014
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Transgene copy number has a great impact on the expression level and stability of exogenous gene in transgenic plants. Proper selection of endogenous reference genes is necessary for detection of genetic components in genetically modification (GM) crops by quantitative real-time PCR (qPCR) or by qualitative PCR approach, especially in sugarcane with polyploid and aneuploid genomic structure. qPCR technique has been widely accepted as an accurate, time-saving method on determination of copy numbers in transgenic plants and on detection of genetically modified plants to meet the regulatory and legislative requirement. In this study, to find a suitable endogenous reference gene and its real-time PCR assay for sugarcane (Saccharum spp. hybrids) DNA content quantification, we evaluated a set of potential "single copy" genes including P4H, APRT, ENOL, CYC, TST and PRR, through qualitative PCR and absolute quantitative PCR. Based on copy number comparisons among different sugarcane genotypes, including five S. officinarum, one S. spontaneum and two S. spp. hybrids, these endogenous genes fell into three groups: ENOL-3--high copy number group, TST-1 and PRR-1--medium copy number group, P4H-1, APRT-2 and CYC-2--low copy number group. Among these tested genes, P4H, APRT and CYC were the most stable, while ENOL and TST were the least stable across different sugarcane genotypes. Therefore, three primer pairs of P4H-3, APRT-2 and CYC-2 were then selected as the suitable reference gene primer pairs for sugarcane. The test of multi-target reference genes revealed that the APRT gene was a specific amplicon, suggesting this gene is the most suitable to be used as an endogenous reference target for sugarcane DNA content quantification. These results should be helpful for establishing accurate and reliable qualitative and quantitative PCR analysis of GM sugarcane.
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In vitro screening of LPS-induced miRNAs in leukocytes derived from cord blood and their possible roles in regulating TLR signals.
Pediatr. Res.
PUBLISHED: 02-10-2014
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microRNAs (miRNAs) are involved in a wide variety of biological processes and play roles in the regulation of Toll-like receptor (TLR) signals. We hypothesized that lipopolysaccharide (LPS)-induced miRNAs in the leukocytes from cord blood (CB) play an important role in newborn innate immunity, specifically in the regulation of the TLR signaling pathway.
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A coarse-grained model for epoxy molding compound.
J Phys Chem B
PUBLISHED: 01-30-2014
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We present a coarse-grained model for molecular dynamics simulations of an epoxy system composed of epoxy phenol novolac as epoxy monomer and bisphenol-A as the cross-linking agent. The epoxy and hardener molecules are represented as short chains of connected beads, and cross-linking is accomplished by introducing bonds between reactive beads. The interbead potential, composed of Lennard-Jones, bond stretching, and angle bending terms, is parametrized through an optimization process based on a particle swarm optimization method to fit certain key thermomechanical properties of the material obtained from experiments and previous full atomistic simulations. The newly developed coarse-grained model is capable of predicting a number of thermomechanical properties of the epoxy system. The predictions are in very good agreement with available data in the literature. More importantly, our coarse-grained model is capable of predicting tensile failure of the epoxy system, a capability that no other conventional molecular dynamic simulation model has. Finally, our coarse-grained model can speed up the simulations by more than an order of magnitude when compared with traditional molecular dynamic simulations.
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Evaluation of plasma Epstein-Barr virus DNA load to distinguish nasopharyngeal carcinoma patients from healthy high-risk populations in Southern China.
Cancer
PUBLISHED: 01-29-2014
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The utility of circulating Epstein-Barr Virus (EBV) DNA as a tumor marker for nasopharyngeal carcinoma (NPC) detection suggests that it might improve the diagnostic performance of anti-EBV antibody markers in NPC screening. In this study, the authors evaluated whether circulating EBV DNA load is capable of distinguishing NPC patients from high-risk individuals who have positive anti-EBV antibodies.
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Genome-wide analysis of radiation-induced mutations in rice (Oryza sativa L. ssp. indica).
Mol Biosyst
PUBLISHED: 01-24-2014
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Radiation has been efficiently used for rice germplasm innovation. However, the molecular mechanisms by which radiation induces mutations are still unclear. In this study, we performed whole genome sequencing to reveal the comprehensive mutations in rice treated with radiation. Red-1 (a rice rich in beneficial ingredients for human health) was derived from rice 9311 after ?-radiation. Solexa sequencing technology was applied to uncover the mutations. Compared with the 9311 genome, 9.19% of genome sequences were altered in the Red-1 genome. Among these alterations, there were 381,403 SNPs, 50,116 1-5 bp Indels, 1279 copy number variations, and 10,026 presence/absence variations. These alterations were located in 14,493 genes, the majority of which contained a kinase domain, leucine rich repeats, or Cyt_P450. Point mutations were the main type of variation in the Red-1 genome. Gene ontology clustering revealed that genes that are associated with cell components, binding function, catalytic activity and metabolic processes were susceptible to ?-radiation. It was also predicted that 8 mutated genes were involved in the biosynthetic pathways of beneficial products or pigment accumulation. We conclude that genome-wide analysis of mutations provides novel insights into the mechanisms by which radiation improves the beneficial ingredients in rice Red-1.
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Comparative diversity analysis of gut microbiota in two different human flora-associated mouse strains.
Curr. Microbiol.
PUBLISHED: 01-16-2014
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The Kunming (KM) mouse is a closed colony mouse strain widely used in Chinese pharmacology, toxicology, and microbiology research laboratories. However, few studies have examined human flora-associated (HFA) microbial communities in KM mice. In this study, HFA models were built from germ-free KM and C57BL/6J mouse strains, and gut microbial diversity was analyzed by denaturing gradient gel electrophoresis (DGGE) and DNA sequencing. We found that the two strains of HFA mice were significantly different based on the UPGMA dendrogram and the Richness index, but dice similarity coefficients of mouse replicates were not significantly different between HFA-KM and HFA-C57BL/6J. Most of the dominant phyla of human gut microflora could be transferred into the guts of the two mouse strains. However, the predominant genus that formed in HFA-KM was Clostridium sp. and that in HFA-C57BL/6J was Blautia sp. These results imply that genotypes difference between the two mice strains is a critical factor in shaping the intestinal microflora. However, genetic differences of individuals within KM mouse populations failed to lead to individual difference in microflora. Successful generation of HFA-KM mice will facilitate studies examining how diet affects gut microbial structure, and will enable comparative studies for uncovering genetic factors that shape gut microbial communities.
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Association of miR-146a gene polymorphism with risk of nasopharyngeal carcinoma in the central-southern Chinese population.
J. Hum. Genet.
PUBLISHED: 01-16-2014
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This case-control study focused on estimating the association between miR-146a polymorphism and risk of nasopharyngeal carcinoma (NPC) in central-south China. In total, 160 patients with NPC and 200 healthy controls in central-south China were genotyped using polymerase chain reaction-restriction fragment length polymorphism assay. Chi-square test was used to assess the different distribution of miR-146a polymorphism between NPC patients and controls; and logistic regression analysis was applied to analyze the associations between miR-146a polymorphism with cancer risk in different contrast models. Significant differences between NPC patients and controls were found in genotype (P=0.033 for GG versus CG versus CC; and odds ratio (OR)=0.568, 95% confidence interval (CI)=0.354-0.912, P=0.019 for CG versus CC; and OR=0.503, 95% CI=0.261-0.971, P=0.041 for CG versus CC; and OR=0.564, 95% CI=0.360-0.884, P=0.012 for GG+CG versus CC, respectively) and allelic analysis (P=0.025 for G versus C). Our findings suggested that polymorphism of mir-146a was associated with NPC in the central-southern Chinese population.
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ScChi, encoding an acidic class III chitinase of sugarcane, confers positive responses to biotic and abiotic stresses in sugarcane.
Int J Mol Sci
PUBLISHED: 01-13-2014
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Chitinases (EC 3.2.2.14), expressed during the plant-pathogen interaction, are associated with plant defense against pathogens. In the present study, a positive correlation between chitinase activity and sugarcane smut resistance was found. ScChi (GenBank accession no. KF664180), a Class III chitinase gene, encoded a 31.37 kDa polypeptide, was cloned and identified. Subcellular localization revealed ScChi targeting to the nucleus, cytoplasm and the plasma membrane. Real-time quantitative PCR (RT-qPCR) results showed that ScChi was highly expressed in leaf and stem epidermal tissues. The ScChi transcript was both higher and maintained longer in the resistance cultivar during challenge with Sporisorium scitamineum. The ScChi also showed an obvious induction of transcription after treatment with SA (salicylic acid), H2O2, MeJA (methyl jasmonate), ABA (abscisic acid), NaCl, CuCl2, PEG (polyethylene glycol) and low temperature (4 °C). The expression levels of ScChi and six immunity associated marker genes were upregulated by the transient overexpression of ScChi. Besides, histochemical assay of Nicotiana benthamiana leaves overexpressing pCAMBIA 1301-ScChi exhibited deep DAB (3,3'-diaminobenzidinesolution) staining color and high conductivity, indicating the high level of H2O2 accumulation. These results suggest a close relationship between the expression of ScChi and plant immunity. In conclusion, the positive responses of ScChi to the biotic and abiotic stimuli reveal that this gene is a stress-related gene of sugarcane.
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Hypoglycemic effect of Gynostemma pentaphyllum saponins by enhancing the Nrf2 signaling pathway in STZ-inducing diabetic rats.
Arch. Pharm. Res.
PUBLISHED: 01-10-2014
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Gynostemma pentaphyllum (GP) is a natural plant resources for diabetes therapy, however, there is little research on the mechanisms of GP. The present study was undertaken to characterize if G. pentaphyllum saponins (GPs) is the principal active compound of GP responsible for anti-diabetes, and to examine the relativity between blood glucose modulate and antioxidation. The GPs-treated streptozotocin diabetic rats had a more effective hypoglycemic status than those of diabetic control rats, which also ameliorate dyslipidemia. GPs has increased SOD and GSH-px activities, and the spleen and thymus indexes in diabetic rats. The insulin levels in the GPs-treated groups were significantly higher than diabetic control group. Our finding provides a new insight into the application of GPs for the treatment of oxidative stress related diseases.
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Structural basis for hijacking CBF-? and CUL5 E3 ligase complex by HIV-1 Vif.
Nature
PUBLISHED: 01-10-2014
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The human immunodeficiency virus (HIV)-1 protein Vif has a central role in the neutralization of host innate defences by hijacking cellular proteasomal degradation pathways to subvert the antiviral activity of host restriction factors; however, the underlying mechanism by which Vif achieves this remains unclear. Here we report a crystal structure of the Vif-CBF-?-CUL5-ELOB-ELOC complex. The structure reveals that Vif, by means of two domains, organizes formation of the pentameric complex by interacting with CBF-?, CUL5 and ELOC. The larger domain (?/? domain) of Vif binds to the same side of CBF-? as RUNX1, indicating that Vif and RUNX1 are exclusive for CBF-? binding. Interactions of the smaller domain (?-domain) of Vif with ELOC and CUL5 are cooperative and mimic those of SOCS2 with the latter two proteins. A unique zinc-finger motif of Vif, which is located between the two Vif domains, makes no contacts with the other proteins but stabilizes the conformation of the ?-domain, which may be important for Vif-CUL5 interaction. Together, our data reveal the structural basis for Vif hijacking of the CBF-? and CUL5 E3 ligase complex, laying a foundation for rational design of novel anti-HIV drugs.
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Toona Sinensis and Moschus Decoction Induced Cell Cycle Arrest in Human Cervical Carcinoma HeLa Cells.
Evid Based Complement Alternat Med
PUBLISHED: 01-08-2014
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Toona sinensis and Moschus are two herb materials used in traditional Chinese medicine, most commonly for their various biological activities. In this study, we investigated the inhibitory effect of three decoctions from Toona sinensis, Moschus, and Toona sinensis and Moschus in combination on cell growth in several normal and cancer cell lines by cell viability assay. The results showed that the combined decoction exhibited the strongest anticancer effects, compared to two single decoctions. The observations indicated that the combined decoction did not induce cell apoptosis and autophagy in HeLa cells by fluorescence microscopy. Flow cytometry analysis revealed that the combined decoction arrested HeLa cell cycle progression in S-phase. After the decoction incubation, among 41 cell cycle related genes, eight were reduced, while five were increased in mRNA levels by real-time PCR assay. Western blotting showed that there were no apparent changes of protein levels of Cyclin E1, while P27 expression significantly declined and the levels of CDC7 and CDK7 obviously increased. The data suggest that the RB pathway is partially responsible for the decoction-induced S-phase cell cycle arrest in HeLa cells. Therefore, the combined decoction may have therapeutic potential as an anticancer formula for certain cancers.
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Electronic metal-support interactions in single-atom catalysts.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 01-06-2014
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The synthesis of single-atom catalysts and the control of the electronic properties of catalytic sites to arrive at superior catalysts is a major challenge in heterogeneous catalysis. A stable supported single-atom silver catalyst with a controllable electronic state was obtained by anti-Ostwald ripening. An electronic perturbation of the catalytic sites that is induced by a subtle change in the structure of the support has a strong influence on the intrinsic reactivity. The higher depletion of the 4d?electronic state of the silver atoms causes stronger electronic metal-support interactions, which leads to easier reducibility and higher catalytic activity. These results may improve our understanding of the nature of electronic metal-support interactions and lead to structure-activity correlations.
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Cyclin D1 G870A Polymorphism and Risk of Nasopharyngeal Carcinoma: A Case-Control Study and Meta-Analysis.
PLoS ONE
PUBLISHED: 01-01-2014
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Cyclin D1 (CCND1) plays a key role in cell cycle regulation. It is a well-established human oncogene which is frequently amplified or overexpressed in cancers. The association between CCND1 G870A polymorphism and cancer risk has been widely assessed. However, a definitive conclusion between CCND1 G870A polymorphism and risk of nasopharyngeal carcinoma (NPC) remains elusive.
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Oral Cadmium in Mice Carrying 5 Versus 2 Copies of the Slc39a8 Gene: Comparison of Uptake, Distribution, Metal Content, and Toxicity.
Int. J. Toxicol.
PUBLISHED: 12-17-2013
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The highly conserved human and mouse SLC39A8 gene encodes the divalent cation/bicarbonate symporter ZIP8 expressed ubiquitously in most cell types. Our bacterial artificial chromosome-transgenic BTZIP8-3 line has 3 additional copies of the Slc39a8 gene in addition to its constitutive diploid pair found in wild-type (WT) mice. In liver, kidney, lung, testis, gastrointestinal tract, and brain, BTZIP8-3 mice are known to express ?2.5 times greater amounts of ZIP8, compared with WT mice. Herein we administered cadmium chloride (CdCl2) in drinking water (100 mg/L through week 2, 200 mg/L through week 4, 400 mg/L through week 8, 800 mg/L through week 12, and 1600 mg/L through week 20, when the experiment was concluded). We postulated that Cd uptake and distribution--and, therefore, toxicity in certain tissues--would be enhanced in BTZIP8-3, compared with WT mice. BTZIP8-3 and WT groups ingested comparable amounts of Cd. Compared with WT, BTZIP8-3 mice showed tissue specific: increases in Cd, zinc, and manganese content and decreases in calcium content. Both Cd-exposed BTZIP8-3 and WT were similar in lower urinary pH; increased plasma alanine and aspartate aminotransferase activities; elevated iron and copper content in liver, kidney, lung, and testis; and higher blood urea nitrogen and kidney weight. Histological changes in liver, kidney, lung, and testis were minimal. In summary, at the daily oral Cd exposures chosen for this study, 5 versus 2 Slc39a8 gene copies result in no differences in Cd toxicity but do cause differences in tissue-specific content of Cd, zinc, manganese, calcium, iron, and copper.
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Multiple scattering of arbitrarily incident Bessel beams by random discrete particles.
J Opt Soc Am A Opt Image Sci Vis
PUBLISHED: 12-11-2013
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In this paper, we introduce an efficient numerical method to characterize the multiple scattering by random discrete particles illuminated by Bessel beams with arbitrary incidence. Specifically, the vector expressions of Bessel beams that perfectly satisfy Maxwells equations in combination with rotation Euler angles are used to represent the arbitrarily incident Bessel beams. A hybrid vector finite element-boundary integral-characteristic-basis function method is utilized to formulate the scattering problems involving multiple discrete particles with a random distribution. Due to the flexibility of the finite element method, the adopted method can conveniently deal with the problems of multiple scattering by randomly distributed homogeneous particles, inhomogeneous particles, and anisotropic particles. Some numerical results are included to illustrate the validity and capability of the proposed method and to show the scattering behaviors of random discrete particles when they are illuminated by Bessel beams.
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Scattering of a zero-order Bessel beam by arbitrarily shaped homogeneous dielectric particles.
J Opt Soc Am A Opt Image Sci Vis
PUBLISHED: 12-11-2013
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In this paper, we introduce an efficient numerical method based on surface integral equations to characterize the scattering of a zero-order Bessel beam by arbitrarily shaped homogeneous dielectric particles. The incident beam is described by vector expressions in terms of the electric and magnetic fields that perfectly satisfy Maxwells equations. The scattering problems involving homogeneous dielectric particles with arbitrary shapes are formulated with the electric and magnetic current combined-field integral equation and modeled by using surface triangular patches. Solutions are performed iteratively by using the multilevel fast multipole algorithm. Some numerical results are included to illustrate the validity and capability of the proposed method. These results are also expected to provide useful insights into the scattering of a Bessel beam by complex-shaped particles.
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Multivariate reference technique for quantitative analysis of fiber-optic tissue Raman spectroscopy.
Anal. Chem.
PUBLISHED: 11-12-2013
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We report a novel method making use of multivariate reference signals of fused silica and sapphire Raman signals generated from a ball-lens fiber-optic Raman probe for quantitative analysis of in vivo tissue Raman measurements in real time. Partial least-squares (PLS) regression modeling is applied to extract the characteristic internal reference Raman signals (e.g., shoulder of the prominent fused silica boson peak (?130 cm(-1)); distinct sapphire ball-lens peaks (380, 417, 646, and 751 cm(-1))) from the ball-lens fiber-optic Raman probe for quantitative analysis of fiber-optic Raman spectroscopy. To evaluate the analytical value of this novel multivariate reference technique, a rapid Raman spectroscopy system coupled with a ball-lens fiber-optic Raman probe is used for in vivo oral tissue Raman measurements (n = 25 subjects) under 785 nm laser excitation powers ranging from 5 to 65 mW. An accurate linear relationship (R(2) = 0.981) with a root-mean-square error of cross validation (RMSECV) of 2.5 mW can be obtained for predicting the laser excitation power changes based on a leave-one-subject-out cross-validation, which is superior to the normal univariate reference method (RMSE = 6.2 mW). A root-mean-square error of prediction (RMSEP) of 2.4 mW (R(2) = 0.985) can also be achieved for laser power prediction in real time when we applied the multivariate method independently on the five new subjects (n = 166 spectra). We further apply the multivariate reference technique for quantitative analysis of gelatin tissue phantoms that gives rise to an RMSEP of ?2.0% (R(2) = 0.998) independent of laser excitation power variations. This work demonstrates that multivariate reference technique can be advantageously used to monitor and correct the variations of laser excitation power and fiber coupling efficiency in situ for standardizing the tissue Raman intensity to realize quantitative analysis of tissue Raman measurements in vivo, which is particularly appealing in challenging Raman endoscopic applications.
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[Hypophosphatemia and chest pain related to adefovir dipivoxil treatment for chronic hepatitis B: report of two cases].
Nan Fang Yi Ke Da Xue Xue Bao
PUBLISHED: 09-27-2013
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Adefovir dipivoxil (ADV) is an acyclic nucleotide phosphate analogue, currently used for anti-HBV therapy. A few cases of hypophosphatemia related to ADV were reviewed. We report two cases of chronic hepatitis B patients with the chief complaints of chest pain due to hypophosphatemia associated with ADV treatment.
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Synthesis and biological evaluation of cyclopentyl-triazolol-pyrimidine (CPTP) based P2Y12 antagonists.
Bioorg. Med. Chem. Lett.
PUBLISHED: 09-04-2013
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In this Letter we describe SAR investigation on the cyclopentyl-triazolol-pyrimidine scaffold in pursuit of new oral P2Y12 inhibitors. Different synthetic routes were developed for variations at the cyclopentyl core. Optimization finally led to compound 2d which was advanced into preclinical development based on better potency and safety profile in comparison to ticagrelor.
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Comparative Studies of Tri- and Hexavalent Chromium Cytotoxicity and Their Effects on Oxidative State of Saccharomyces cerevisiae Cells.
Curr. Microbiol.
PUBLISHED: 08-24-2013
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Chromium is a significant mutagen and carcinogen in environment. We compared the effects of tri- and hexavalent chromium on cytotoxicity and oxidative stress in yeast. Cell growth was inhibited by Cr(3+) or Cr(6+), and Cr(6+) significantly increased the lethal rate compared with Cr(3+). Both Cr(3+) and Cr(6+) can enter into the yeast cells. The percent of propidium iodide permeable cells treated with Cr(3+) is almost five times as that treated with the same concentration of Cr(6+). Levels of TBARS, O2 (-), and carbonyl protein were significantly increased in both Cr(6+)- and Cr(3+)-treated cells in a concentration- and time-dependent manner. Moreover, the accumulation of these stress markers in Cr(6+)-treated cells was over the Cr(3+)-treated ones. The decreased GSH level and increased activity of GPx were observed after 300 ?M Cr(6+)-exposure compared with the untreated control, whereas there was no other change of GSH content in cells treated with Cr(3+) even at very high concentration. Exposure to both Cr(3+) and Cr(6+) resulted in the decrease of activities of SOD and catalase. Furthermore, the effect of Cr(6+) is stronger than that of Cr(3+). Null mutation sensitivity assay demonstrated that the gsh1 mutant was sensitive to Cr(6+) other than Cr(3+), the apn1 mutant is more sensitive to Cr(6+) than Cr(3+), and the rad1 mutant is sensitive to both Cr(6+) and Cr(3+). Therefore, Cr(3+) can be concluded to inhibit cell growth probably due to the damage of plasma membrane integrality in yeast. Although both tri- and hexavalent chromium can induce cytotoxicity and oxidative stress, the action mode of Cr(3+) is different from that of Cr(6+), and serious membrane damage caused by Cr(3+) is not the direct consequence of the increase of lipid peroxidation.
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Development of a beveled fiber-optic confocal Raman probe for enhancing in vivo epithelial tissue Raman measurements at endoscopy.
Opt Lett
PUBLISHED: 07-02-2013
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We report on the development of a beveled fiber-optic confocal Raman probe coupled with a ball lens for enhancing in vivo epithelial tissue Raman measurements at endoscopy. Our Monte Carlo simulations show that by selecting a proper fiber-ball lens distance and beveled angle of collection fibers, the confocal Raman probe design can be optimized for maximizing shallower tissue Raman measurements in epithelial tissue; in addition, the ratio of epithelium to stromal Raman photons collected using an optimized confocal Raman probe is approximately 19-fold higher than that using a volume-type Raman probe. Further experiments confirm that the confocal Raman endoscopic probe developed is in favor of probing superficial tissue Raman signals from a two-layer tissue phantom as well as esophagus tissue in vivo during endoscopy. This work suggests the great potential of applying the beveled fiber-optic confocal Raman probe for improving in vivo diagnosis of precancer occurring in epithelial tissue at endoscopy.
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Near-infrared-excited confocal Raman spectroscopy advances in vivo diagnosis of cervical precancer.
J Biomed Opt
PUBLISHED: 06-26-2013
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Raman spectroscopy is a unique optical technique that can probe the changes of vibrational modes of biomolecules associated with tissue premalignant transformation. This study evaluates the clinical utility of confocal Raman spectroscopy over near-infrared (NIR) autofluorescence (AF) spectroscopy and composite NIR AF/Raman spectroscopy for improving early diagnosis of cervical precancer in vivo at colposcopy. A rapid NIR Raman system coupled with a ball-lens fiber-optic confocal Raman probe was utilized for in vivo NIR AF/Raman spectral measurements of the cervix. A total of 1240 in vivo Raman spectra [normal (n=993), dysplasia (n=247)] were acquired from 84 cervical patients. Principal components analysis (PCA) and linear discriminant analysis (LDA) together with a leave-one-patient-out, cross-validation method were used to extract the diagnostic information associated with distinctive spectroscopic modalities. The diagnostic ability of confocal Raman spectroscopy was evaluated using the PCA-LDA model developed from the significant principal components (PCs) [i.e., PC4, 0.0023%; PC5, 0.00095%; PC8, 0.00022%, (p<0.05)], representing the primary tissue Raman features (e.g., 854, 937, 1095, 1253, 1311, 1445, and 1654 cm(-1)). Confocal Raman spectroscopy coupled with PCA-LDA modeling yielded the diagnostic accuracy of 84.1% (a sensitivity of 81.0% and a specificity of 87.1%) for in vivo discrimination of dysplastic cervix. The receiver operating characteristic curves further confirmed that the best classification was achieved using confocal Raman spectroscopy compared to the composite NIR AF/Raman spectroscopy or NIR AF spectroscopy alone. This study illustrates that confocal Raman spectroscopy has great potential to improve early diagnosis of cervical precancer in vivo during clinical colposcopy.
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[Research on biometric method of heart sound signal based on GMM].
Zhongguo Yi Liao Qi Xie Za Zhi
PUBLISHED: 06-20-2013
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Extraction of cepstral coefficients combined with Gaussian Mixture Model (GMM) is used to propose a biometric method based on heart sound signal.
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Conformational preferences of furan- and thiophene-based arylamides: a combined computational and experimental study.
Phys Chem Chem Phys
PUBLISHED: 06-15-2013
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We examine the conformational preferences of the furan- and thiophene-based arylamides, N-methylfuran-2-carboxamide (3) and N-methylthiophene-2-carboxamide (4), using a combination of computational methods and NMR experiments. The compound choice stems from their use as foldamer building blocks. We quantify the differences in the conformational rigidity of the two compounds, which governs corresponding foldamer conformations. Specifically, we demonstrate the effects of intramolecular hydrogen bonding (H-bonding), geometrical patterns and solvent polarity on arylamide conformations by comparing 3, 4 and previously studied ortho-methoxy N-methylbenzamide (1) and ortho-methylthio N-methylbenzamide (2). The study reveals that compound 3, despite its non-optimal S(5)-type H-bond geometry, retains a large portion of the H-bonded (eclipsed) conformation even in polar protic solvents. This behaviour is consistent with the quantum mechanical (QM) torsional energy profile. The percentages of H-bonded conformers that 3 retains are just slightly smaller than those of 1, which has a stronger S(6)-type H-bond. As for 2 and 4, the replacement of the O atom in 1 by an S atom in 2 results in a 70–90% loss of the H-bonded conformer in solution. However, the equivalent O to S replacement in 3 (leading to 4) causes only 15–30% loss of the eclipsed conformers in 4. Therefore, conformational preferences of 4 are very different from 2, in contrast to the similarity between 3 and 1. This study shows how the interplay of several forces modulates the conformational flexibility of arylamides. It also attests the strategy we are developing, which leads to accurate prediction of foldamer structure. The vital component of this strategy is the re-parameterization of critical force field parameters based on QM potential energy profiles, as well as validation of these parameters using experimental data in solution.
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Thermomechanical properties and deformation of coarse-grained models of hard-soft block copolymers.
Phys Rev E Stat Nonlin Soft Matter Phys
PUBLISHED: 06-13-2013
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In this paper, we investigate the enhancement mechanism of the mechanical properties for hard-soft block copolymers by using molecular dynamics simulations at various temperatures. A coarse-grained approach is adopted to study sufficiently generic models. Our numerical experiments demonstrate that the nonbond potential plays a more significant role in mechanical properties compared to the bond potential. This finding serves as a cornerstone to understand the hard-soft materials. To explore the effect of hard segments, four copolymers with different concentrations and energy factors that describe the interaction between hard beads are conducted. Simulation results show that the mechanical performances of the system with large attractive force and small concentration of hard segments could be improved dramatically in conjunction with a moderate increment of the glass transition temperature. In particular, the energy factor shows a substantial influence in determining the microphase separation as well as the morphology of hard domains. These observations are believed to provide design guidelines for polymeric materials in engineering practice.
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Crystal structure of NLRC4 reveals its autoinhibition mechanism.
Science
PUBLISHED: 06-13-2013
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Nucleotide-binding and oligomerization domain-like receptor (NLR) proteins oligomerize into multiprotein complexes termed inflammasomes when activated. Their autoinhibition mechanism remains poorly defined. Here, we report the crystal structure of mouse NLRC4 in a closed form. The adenosine diphosphate-mediated interaction between the central nucleotide-binding domain (NBD) and the winged-helix domain (WHD) was critical for stabilizing the closed conformation of NLRC4. The helical domain HD2 repressively contacted a conserved and functionally important ?-helix of the NBD. The C-terminal leucine-rich repeat (LRR) domain is positioned to sterically occlude one side of the NBD domain and consequently sequester NLRC4 in a monomeric state. Disruption of ADP-mediated NBD-WHD or NBD-HD2/NBD-LRR interactions resulted in constitutive activation of NLRC4. Together, our data reveal the NBD-organized cooperative autoinhibition mechanism of NLRC4 and provide insight into its activation.
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Numerical simulation and experiment on multilayer stagger-split die.
Rev Sci Instrum
PUBLISHED: 06-08-2013
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A novel ultra-high pressure device, multilayer stagger-split die, has been constructed based on the principle of "dividing dies before cracking." Multilayer stagger-split die includes an encircling ring and multilayer assemblages, and the mating surfaces of the multilayer assemblages are mutually staggered between adjacent layers. In this paper, we investigated the stressing features of this structure through finite element techniques, and the results were compared with those of the belt type die and single split die. The contrast experiments were also carried out to test the bearing pressure performance of multilayer stagger-split die. It is concluded that the stress distributions are reasonable and the materials are utilized effectively for multilayer stagger-split die. And experiments indicate that the multilayer stagger-split die can bear the greatest pressure.
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Non-invasive analysis of hormonal variations and effect of postmenopausal Vagifem treatment on women using in vivo high wavenumber confocal Raman spectroscopy.
Analyst
PUBLISHED: 06-03-2013
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This study aims to evaluate the feasibility of applying high wavenumber (HW) confocal Raman spectroscopy for non-invasive assessment of menopause-related hormonal changes in the cervix as well as for determining the effect of Vagifem(®) treatment on postmenopausal women with atrophic cervix. A rapid HW confocal Raman spectroscopy system coupled with a ball lens fiber-optic Raman probe was utilized for in vivo cervical tissue Raman measurements at 785 nm excitation. A total of 164 in vivo HW Raman spectra (premenopausal (n = 104), postmenopausal-prevagifem (n = 34), postmenopausal-postvagifem (n = 26)) were measured from the normal cervix of 26 patients undergoing colposcopy. We established the biochemical basis of premenopausal, postmenopausal-prevagifem and postmenopausal-postvagifem cervix using semiquantitative biomolecular modeling derived from Raman-active biochemicals (i.e., lipids, proteins and water) that play a critical role in HW Raman spectral changes associated with the menopausal process. The diagnostic algorithms developed based on partial least squares-discriminant analysis (PLS-DA) together with leave-one patient-out, cross-validation yielded the diagnostic sensitivities of 88.5%, 91.2% and 88.5%, and specificities of 91.7%, 90.8% and 99.3%, respectively, for non-invasive in vivo discrimination among premenopausal, postmenopausal-prevagifem and postmenopausal-postvagifem cervix. This work demonstrates for the first time that HW confocal Raman spectroscopy in conjunction with biomolecular modeling can be a powerful diagnostic tool for identifying hormone/menopause-related variations in the native squamous epithelium of normal cervix, as well as for assessing the effect of Vagifem treatment on postmenopausal atrophic cervix in vivo during clinical colposcopic inspections.
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Imbalance between Th17 and regulatory T-Cells in sarcoidosis.
Int J Mol Sci
PUBLISHED: 05-27-2013
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Sarcoidosis is a systemic granulomatous disease, which is thought to result from an aberrant immune response. CD4+ T lymphocytes play an important role in the development of granulomas. Previously, the immunopathogenesis of sarcoidosis was focused on Th1/Th2 disturbances. The aim of this study was to evaluate the balance between newer CD4+ T lymphocytes, i.e., Treg and Th17 cells. In our studies, a decrease in Treg cells and an increase in Th17 cells were observed in the peripheral blood and BALF of sarcoidosis patients. A significant increase in the Th17/Treg cell ratio was observed in sarcoidosis patients. After treatment with prednisone, the expression of Foxp3 mRNA was elevated in the peripheral blood, and expression of (ROR)?t mRNA showed a downward trend. These findings suggest that sarcoidosis is associated with an imbalance between Th17 and Treg cells in peripheral blood and BALF. Therefore, targeting the cytokines that affect the Th17/Treg ratio could provide a new promising therapy for pulmonary sarcoidosis.
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Constructing lanthanide [Nd(III), Er(III) and Yb(III)] complexes using a tridentate N,N,O-ligand for near-infrared organic light-emitting diodes.
Dalton Trans
PUBLISHED: 05-13-2013
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A novel type of NIR-emitting lanthanide complexes Ln(PND)3 (Ln = Nd, Er and Yb) was designed and synthesized based on a tridentate monoanionic N,N,O-ligand 6-(pyridin-2-yl)-1,5-naphthyridin-4-ol (PND). Such complex owns definite charge-neutral, coordination-saturated and mononuclear structure that is proved by X-ray single crystal diffraction of Nd(PND)3. Photophysical studies on the ligand and complexes reveal that the PND ligand has suitable energy level to sensitize the near-infrared (NIR) emitting lanthanide ions (Nd(3+), Er(3+), and Yb(3+)). Among the three compounds, Yb(PND)3 shows the highest photoluminescence quantum yield up to 0.9% in a mixture of acetonitrile and methanol solution (10 : 1, v/v, 10(-4) M). Thermal measurements indicate that these compounds have high decomposition (Td) and glass transition (Tg) temperature up to 420 and 265 °C, respectively, implying great advantage for constructing organic electronic devices via vacuum deposition method. At last, NIR organic light-emitting diodes (OLEDs) with simple three-layer structure were fabricated to test their electroluminescent performance, showing maximum NIR irradiance and maximum external quantum efficiency (EQE) of 25 ?W cm(-2) and 0.019% for Nd(3+), 0.46 ?W cm(-2) and 0.004% for Er(3+), and 86 ?W cm(-2) and 0.14% for Yb(3+), respectively.
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Long non-coding RNA: a new player in cancer.
J Hematol Oncol
PUBLISHED: 05-08-2013
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Emerging evidence showed that long non-coding RNAs (lncRNAs) play important roles in a wide range of biological processes and dysregulated lncRNAs are involved in many complex human diseases, including cancer. Although a few lncRNAs functions in cancer have been characterized, the detailed regulatory mechanisms of majority of lncRNAs in cancer initiation and progression remain largely unknown. In this review, we summarized recent progress on the mechanisms and functions of lncRNAs in cancer, especially focusing on the oncogenic and tumor suppressive roles of the newly identified lncRNAs, and the pathways these novel molecules might be involved in. Their potentials as biomarkers for diagnosis and prognosis in cancer are also discussed in this paper.
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Serum leptin, adiponectin and endometrial cancer risk in Chinese women.
J Gynecol Oncol
PUBLISHED: 04-30-2013
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To investigate the relationship between serum concentrations of leptin or adiponectin, and endometrial carcinoma in Chinese women.
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Effects of Placental Inflammation on Neonatal Outcome in Preterm Infants.
Pediatr Neonatol
PUBLISHED: 04-29-2013
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Intrauterine infection is the most commonly identified cause of preterm birth. In this study, our aim was to determine the association between placental inflammation and neonatal outcome in a prospective observational cohort of preterm infants of less than 34 weeks gestational age. We especially focused on the distinct effects of maternal inflammatory response (MIR) with and without fetal inflammatory response (FIR).
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Circularly polarized coherent anti-Stokes Raman scattering microscopy.
Opt Lett
PUBLISHED: 04-19-2013
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We demonstrate circularly polarized coherent anti-Stokes Raman scattering (CP-CARS) microscopy that significantly suppresses the nonresonant background for high-contrast vibrational imaging. Circularly polarized pump and Stokes fields with opposite handedness are used to excite CARS signal. In this case, theoretically the nonresonant CARS signal and resonant CARS signal from isotropic media will completely vanish, while the resonant CARS signal from anisotropic structures can still exist. This allows CARS imaging of anisotropic samples with enhanced resonant contrast. Furthermore, we performed CP-CARS imaging on fibroin fibers from silkworm silk, and the results confirmed its effectiveness in background suppression.
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Prolyl isomerase Pin1 regulated signaling pathway revealed by Pin1 +/+ and Pin1 -/- mouse embryonic fibroblast cells.
Pathol. Oncol. Res.
PUBLISHED: 03-22-2013
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Pin1 (peptidylprolyl cis/trans isomerase, NIMA-interacting 1) plays a key role in a number of diseases including cancer and Alzheimer disease. Previous studies have identified a wide range of phosphoproteins as Pin1 substrates. Related pathways were analyzed separately. The aim of this study was to provide a comprehensive picture involving Pin1 regulation. A genome-wide mRNA expression microarray was carried out using the RNA isolation from Pin1 (+/+) and Pin1 (-/-) mouse embryonic fibroblast (MEF) cells. Signaling pathways regulated by Pin1 were analyzed with the utility of KEGG pathway and GO annotation. An expression pattern regulated by Pin1 was revealed. A total of 606 genes, 375 being up-regulated and 231 down-regulated, were differentially expressed when comparing Pin1 +/+ to Pin1 -/- MEF cells. Totally 48 pathways were shown to be regulated by Pin1 expression in KEGG pathway analysis. In the GO annotation system, 19 processes on biological processes, 15 processes on cellular components, and 18 processes on molecular functions were found to be in the regulation of Pin1 expression. Pathways related to immune system and cancer showed most significant association with Pin1 regulation. Pin1 is an important regulator in a wide range of signaling pathways that were related to immune system and cancer.
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Ionic Extraction of a Novel Nano-sized Bioactive Glass Enhances Differentiation and Mineralization of Human Dental Pulp Cells.
J Endod
PUBLISHED: 03-21-2013
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This study aimed to investigate the effects of a novel nano-sized 58S bioactive glass (nano-58S BG) on the odontogenic differentiation and mineralization of human dental pulp cells (hDPCs) in vitro.
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Dual roles of FBXL3 in the mammalian circadian feedback loops are important for period determination and robustness of the clock.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 03-05-2013
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The mammalian circadian clock is composed of interlocking feedback loops. Cryptochrome is a central component in the core negative feedback loop, whereas Rev-Erb?, a member of the nuclear receptor family, is an essential component of the interlocking loop. To understand the roles of different clock genes, we conducted a genetic interaction screen by generating single- and double-mutant mice. We found that the deletion of Rev-erb? in F-box/leucine rich-repeat protein (Fbxl3)-deficient mice rescued its long-circadian period phenotype, and our results further revealed that FBXL3 regulates Rev-Erb/retinoic acid receptor-related orphan receptor-binding element (RRE)-mediated transcription by inactivating the Rev-Erb?:histone deacetylase 3 corepressor complex. By analyzing the Fbxl3 and Cryptochrome 1 double-mutant mice, we found that FBXL3 also regulates the amplitudes of E-box-driven gene expression. These two separate roles of FBXL3 in circadian feedback loops provide a mechanism that contributes to the period determination and robustness of the clock.
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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.