577 research outputs found
Fluorescent Probes for Analysis and Imaging of Monoamine Oxidase Activity
Monoamine oxidases catalyze the oxidative deamination of dietary amines and amine neurotransmitters, and assist in maintaining the homeostasis of the amine neurotransmitters in the brain. Dysfunctions of these enzymes can cause neurological and behavioral disorders including Parkinson's and Alzheimer's diseases. To understand their physiological roles, efficient assay methods for monoamine oxidases are essential. Reviewed in this Perspective are the recent progress in the development of fluorescent probes for monoamine oxidases and their applications to enzyme assays in cells and tissues. It is evident that still there is strong need for a fluorescent probe with desirable substrate selectivity and photophysical properties to challenge the much unsolved issues associated with the enzymes and the diseases.X1132Ysciescopu
Trioctylphosphine as Both Solvent and Stabilizer to Synthesize CdS Nanorods
High quality CdS nanorods are synthesized reproducibly with cadmium acetate and sulfur as precursors in trioctylphosphine solution. The morphology, crystalline form and phase composition of CdS nanorods are characterized by transmission electron microscopy (TEM), high-resolution TEM and X-ray diffraction (XRD). CdS nanorods obtained are uniform with an aspect ratio of about 5:1 and in a wurtzite structure. The influence of reaction conditions on the growth of CdS nanorods demonstrates that low precursor concentration and high reaction temperature (260 °C) are favorable for the formation of uniform CdS nanorods with 85.3% of product yield
Control of electronic conduction at an oxide heterointerface using surface polar adsorbates
The transfer of electrons between a solid surface and adsorbed atomic or
molecular species is fundamental in natural and synthetic processes, being at
the heart of most catalytic reactions and many sensors. In special cases,
metallic conduction can be induced at the surface of, for example,
Si-terminated SiC1, or mixed-terminated ZnO2, in the presence of a hydrogen
adlayer. Generally, only the surface atoms are significantly affected by
adsorbates. However, remotely changing electronic states far from the adsorbed
layer is possible if these states are electrostatically coupled to the surface.
Here we show that the surface adsorption of common solvents such as acetone,
ethanol, and water can induce a large change (factor of three) in the
conductivity at the buried interface between SrTiO3 substrates and LaAlO3 thin
films3-8. This phenomenon is observed only for polar solvents. Our result
provides experimental evidence that adsorbates at the LaAlO3 surface induce
accumulation of electrons at the LaAlO3/SrTiO3 interface, suggesting a general
polarization-facilitated electronic transfer mechanism, which can be used for
sensor applications.Comment: 14 pages, 4 figure
Polymorphisms in the interleukin-10 gene cluster are possibly involved in the increased risk for major depressive disorder
<p>Abstract</p> <p>Background</p> <p>Innate immune inflammatory response is suggested to have a role in the pathogenesis of major depressive disorder (MDD). Interleukin (IL)-10 family cytokines IL-10, IL-19, IL-20, and IL-24 are all implicated in the inflammatory processes and polymorphisms in respective genes have been associated with various immunopathological conditions. This study was carried out to investigate whether single-nucleotide polymorphisms (SNPs) in these genes are also associated with MDD.</p> <p>Methods</p> <p>Case-control association study was performed with seven SNPs from the <it>IL10 </it>gene cluster. 153 patients with MDD and 277 healthy control individuals were recruited.</p> <p>Results</p> <p>None of the selected SNPs were individually associated with MDD. The linkage disequilibrium (LD) analysis indicated the existence of two recombination sites in the <it>IL10 </it>gene cluster, thus confirming the formerly established LD pattern of this genomic region. This also created two haplotype blocks, both consisting of three SNPs. Additionally, the haplotype analysis detected a significantly higher frequency of block 2 (<it>IL20 </it>and <it>IL24 </it>genes) haplotype TGC in the patients group compared to healthy control individuals (P = 0.0097).</p> <p>Conclusion</p> <p>Our study established increased risk for MDD related to the <it>IL20 </it>and <it>IL24 </it>haplotype and suggests that cytokines may contribute to the pathogenesis of MDD. Since none of the block 2 SNPs were individually associated with MDD, it is possible that other polymorphisms linked to them contribute to the disease susceptibility. Future studies are needed to confirm the results and to find the possible functional explanation.</p
Single nanowire-based UV photodetectors for fast switching
Relatively long (30 µm) high quality ZnO nanowires (NWs) were grown by the vapor-liquid-solid (VLS) technique. Schottky diodes of single NW were fabricated by putting single ZnO NW across Au and Pt electrodes. A device with ohmic contacts at both the sides was also fabricated for comparison. The current-voltage (I-V) measurements for the Schottky diode show clear rectifying behavior and no reverse breakdown was seen down to -5 V. High current was observed in the forward bias and the device was found to be stable up to 12 V applied bias. The Schottky barrier device shows more sensitivity, lower dark current, and much faster switching under pulsed UV illumination. Desorption and re-adsorption of much smaller number of oxygen ions at the Schottky junction effectively alters the barrier height resulting in a faster response even for very long NWs. The NW was treated with oxygen plasma to improve the switching. The photodetector shows high stability, reversibility, and sensitivity to UV light. The results imply that single ZnO NW Schottky diode is a promising candidate for fabricating UV photodetectors
Effects of Proteins from Culture Medium on Surface Property of Silanes- Functionalized Magnetic Nanoparticles
Monodisperse magnetic nanoparticles (MNPs) were synthesized by thermal decomposition of iron-oleate and functionalized with silanes bearing various functional groups such as amino group (NH2), short-chain poly(ethylene glycol) (PEG), and carboxylic group (COOH). Then, silanes-functionalized magnetic nanoparticles (silanes-MNPs) were incubated in cell culture medium plus fetal calf serum to investigate the effects of proteins from culture medium on surface property of MNPs. Zeta potential measurements showed that although surface charges of silanes-MNPs were different, they exhibited negative charges at neutral pH and approximate isoelectric points after they were incubated in cell culture medium. The reason was that silanes-MNPs could easily adsorb proteins from culture medium via non-covalent binding, resulting in the formation of protein-silanes-MNPs conjugates. Moreover, silanes-MNPs with various functional groups had different adsorption capacity to proteins, as confirmed by Coomassie blue fast staining method. The in vitro cell experiments showed that protein-silanes-MNPs had higher cellular uptake by cancer cells than silanes-MNPs
CHD7 Mutational Analysis and Clinical Considerations for Auditory Rehabilitation in Deaf Patients with CHARGE Syndrome
BACKGROUND: Otologic manifestations are one of the most consistent findings of CHARGE syndrome found in more than 90%. Since genetic analysis of the CHD7 gene has rarely been performed in previous reports dealing with ear abnormalities, the genotypic spectrum of CHD7 mutations was analyzed in deaf patients with CHARGE syndrome, and the clinical considerations concerning auditory rehabilitation were investigated. METHODS: Nine Korean patients with CHARGE syndrome showing profound hearing loss and semicircular canal aplasia were included. All 38 exons of CHD7 were analyzed by direct sequencing. For splice site variations, in silico and exon-trapping analyses were performed to verify the pathogenicity of nucleotide variations. Clinical features and the outcome of auditory rehabilitation were also analyzed. RESULTS: Eight of 9 patients revealed alterations of the CHD7 gene including 3 frameshift, 2 nonsense, 2 splice site, and 1 missense mutations. Five of 9 patients were clinically diagnosed as atypical CHARGE syndrome but demonstrated various mutations of the CHD7 gene. One familial case showed intra-familial variability. Radiologic findings suggesting cochleovestibular nerve deficiency were identified in most of the patients. Of the 8 patients who underwent cochlear implantation, 5 patients demonstrated favorable outcome. Larger diameter of the cochleovestibular nerve on imaging and absence of severe mental retardation were factors related to better outcome after cochlear implantation rather than the type of CHD7 mutations. Auditory brainstem implantation was performed in two patients who did not benefit from cochlear implantation. CONCLUSIONS: Genetic analysis of the CHD7 gene should be performed in cases with semicircular canal aplasia even when other typical features of CHARGE syndrome are absent. For auditory rehabilitation in CHARGE syndrome, cochlear implantation should be strongly recommended in selected cases with favorable prognostic factors. Auditory brainstem implantation may be a viable option in patients with CHARGE syndrome who have failed to benefit from cochlear implantation
Potential new genes for resistance to Mycosphaerella graminicola identified in Triticum aestivum x Lophopyrum elongatum disomic substitution lines.
Lophopyrum species carry many desirable agronomic traits, including disease resistance, which can be transferred towheat by interspecific hybridization. To identify potentially new genes for disease and insect resistance carried by individual Lophopyrum chromosomes, 19 of 21 possible wheat cultivar Chinese Spring 9 Lophopyrum elongatum disomic substitution lines were tested for resistance to barley yellow dwarf virus (BYDV), cereal yellow dwarf virus (CYDV), the Hessian fly Mayetiola destructor, and the fungal pathogens Blumeria graminis and Mycosphaerella graminicola (asexual stage: Septoria tritici). Low resistance to BYDV occurred in some of the disomic substitution lines, but viral titers were significantly higher than those of two Lophopyrum species tested. This suggested that genes on more than one Lophopyrum chromosome are required for complete resistance to this virus. A potentially new gene for resistance to CYDV was detected on wheatgrass chromosome 3E. All of the
substitution lines were susceptible to Mayetiola destructor
and one strain of B. graminis. Disomic substitution lines containing wheatgrass chromosomes 1E and 6E were significantly more resistant to M. graminicola compared to Chinese Spring. Although neither chromosome by itself conferred resistance as high as that in the wheatgrass parent, they do appear to contain potentially new genes for resistance against this pathogen that could be useful for future plant-improvement programs
Laparoscopic and open resection for colorectal cancer: an evaluation of cellular immunity
<p>Abstract</p> <p>Background</p> <p>Colorectal cancer is one kind of frequent malignant tumors of the digestive tract which gets high morbidity and mortality allover the world. Despite the promising clinical results recently, less information is available regarding the perioperative immunological effects of laparoscopic surgery when compared with the open surgery. This study aimed to compare the cellular immune responses of patients who underwent laparoscopic(LCR) and open resections(OCR) for colorectal cancer.</p> <p>Methods</p> <p>Between Mar 2009 and Sep 2009, 35 patients with colorectal carcinoma underwent LCR by laparoscopic surgeon. These patients were compared with 33 cases underwent conventional OCR by colorectal surgeon. Clinical data about the patients were collected prospectively. Comparison of the operative details and postoperative outcomes between laparoscopic and open resection was performed. Peripheral venous blood samples from these 68 patients were taken prior to surgery as well as on postoperative days(POD) 1, 4 and 7. Cell counts of total white blood cells, neutrophils, lymphocyte subpopulations, natural killer(NK) cells as well as CRP were determined by blood counting instrument, flow cytometry and hematology analyzer.</p> <p>Results</p> <p>There was no difference in the age, gender and tumor status between the two groups. The operating time was a little longer in the laparoscopic group (<it>P </it>> 0.05), but the blood loss was less (<it>P </it>= 0.039). Patients with laparoscopic resection had earlier return of bowel function and earlier resumption of diet as well as shorter median hospital stay (<it>P </it>< 0.001). Compared with OCR group, cell numbers of total lymphocytes, CD4<sup>+</sup>T cells and CD8<sup>+</sup>T cells were significant more in LCR group (<it>P </it>< 0.05) on POD 4, while there was no difference in the CD45RO<sup>+</sup>T or NK cell numbers between the two groups. Cellular immune responds were similar between the two groups on POD1 and POD7.</p> <p>Conclusions</p> <p>Laparoscopic colorectal resection gets less surgery stress and short-term advantages compared with open resection. Cellular immune respond appears to be less affected by laparoscopic colorectal resection when compared with open resection.</p
The Effect of Iron Oxide Magnetic Nanoparticles on Smooth Muscle Cells
Recently, magnetic nanoparticles of iron oxide (Fe3O4, γ-Fe2O3) have shown an increasing number of applications in the field of biomedicine, but some questions have been raised about the potential impact of these nanoparticles on the environment and human health. In this work, the three types of magnetic nanoparticles (DMSA-Fe2O3, APTS-Fe2O3, and GLU-Fe2O3) with the same crystal structure, magnetic properties, and size distribution was designed, prepared, and characterized by transmission electronic microscopy, powder X-ray diffraction, zeta potential analyzer, vibrating sample magnetometer, and Fourier transform Infrared spectroscopy. Then, we have investigated the effect of the three types of magnetic nanoparticles (DMSA-Fe2O3, APTS-Fe2O3, and GLU-Fe2O3) on smooth muscle cells (SMCs). Cellular uptake of nanoparticles by SMC displays the dose, the incubation time and surface property dependent patterns. Through the thin section TEM images, we observe that DMSA-Fe2O3is incorporated into the lysosome of SMCs. The magnetic nanoparticles have no inflammation impact, but decrease the viability of SMCs. The other questions about metabolism and other impacts will be the next subject of further studies
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