363 research outputs found

    G-quadruplex formation in human telomeric (TTAGGG)4 sequence with complementary strand in close vicinity under molecularly crowded condition

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    Chromosomes in vertebrates are protected at both ends by telomere DNA composed of tandem (TTAGGG)n repeats. DNA replication produces a blunt-ended leading strand telomere and a lagging strand telomere carrying a single-stranded G-rich overhang at its end. The G-rich strand can form G-quadruplex structure in the presence of K+ or Na+. At present, it is not clear whether quadruplex can form in the double-stranded telomere region where the two complementary strands are constrained in close vicinity and quadruplex formation, if possible, has to compete with the formation of the conventional Watson–Crick duplex. In this work, we studied quadruplex formation in oligonucleotides and double-stranded DNA containing both the G- and C-rich sequences to better mimic the in vivo situation. Under such competitive condition only duplex was observed in dilute solution containing physiological concentration of K+. However, quadruplex could preferentially form and dominate over duplex structure under molecular crowding condition created by PEG as a result of significant quadruplex stabilization and duplex destabilization. This observation suggests quadruplex may potentially form or be induced at the blunt end of a telomere, which may present a possible alternative form of structures at telomere ends

    Fully Band Resolved Scattering Rate in MgB2 Revealed by Nonlinear Hall Effect and Magnetoresistance Measurements

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    We have measured the normal state temperature dependence of the Hall effect and magnetoresistance in epitaxial MgB2 thin films with variable disorders characterized by the residual resistance ratio RRR ranging from 4.0 to 33.3. A strong nonlinearity of the Hall effect and magnetoresistance have been found in clean samples, and they decrease gradually with the increase of disorders or temperature. By fitting the data to the theoretical model based on the Boltzmann equation and ab initio calculations for a four-band system, for the first time, we derived the scattering rates of these four bands at different temperatures and magnitude of disorders. Our method provides a unique way to derive these important parameters in multiband systems.Comment: 4 pages, 4 figure

    FeCl3-Catalyzed Propargylation-Cycloisomerization Tandem Reaction: A Facile One-Pot Synthesis of Substituted Furans

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    An efficient FeCl3-catalyzed tandem propargylation-cycloisomerization reaction of propargylic alcohols or acetates with 1,3-dicarbonyl compounds, leading to the synthesis of substituted furans, has been developed.National Natural Science Foundation of China [20772098, 30572250]; Fujian Province Universit

    Capsule membranes encapsulated with smart nanogels for facile detection of trace lead(II) ions in water

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    A novel method based on capsule membranes encapsulated with smart nanogels is successfully developed for facilely detecting trace lead(II) (Pb2+) ions, which are hazardous to both human health and the environment because of their toxicity. The capsule membrane system is composed of a semi-permeable calcium alginate membrane and encapsulated poly(N-isopropylacrylamide-co-acryloylamidobenzo-18-crown-6) (PNB) nanogels. The semi-permeable membrane allows Pb2+ ions and water to pass through quickly, but rejects the encapsulated nanogels and polymers totally. As soon as Pb2+ ions appear in the aqueous environment and enter into the capsule, they can be specifically recognized by encapsulated PNB nanogels via forming 18-crown-6/Pb2+ complexes that cause a Pb2+-induced phase transition of PNB nanogels from hydrophobic to hydrophilic state. As a result, the osmotic pressure inside the capsule membrane increases remarkably, and thus the elastic capsule membrane isothermally swells upon the presence of Pb2+ ions in the environmental aqueous solution. The Pb2+-induced swelling degree of the capsule membrane is dependent on the concentration of Pb2+ ions ([Pb2+]) in water. Thus, the [Pb2+] value in water is able to be easily detected by directly measuring the Pb2+-induced isothermal swelling ratio of the capsule membrane, which we demonstrate by using 15 prepared capsule membranes arranged in a line. The Pb2+-induced swelling ratios of the capsule membrane groups are easily observed with the naked eye, and the detection limit of the [Pb2+] in water is 10-9 mol L-1. Such a proposed method provides an easy and efficient strategy for facile detection of trace threat analytes in water

    Depressive Neurosis Treated by Acupuncture for Regulating the Liver —A Report of 176 Cases

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    ObjectiveTo observe therapeutic effect of acupuncture for regulating the liver on depressive neurosis.MethodsIn a multi-center randomized controlled trial, 440 patients were divided into 3 groups: Acupuncture group for regulating the liver (Acup., 176 cases) was treated by acupuncture at Siguan Points, i.e. bilateral Hegu (LI 4) and Taichong (LR 3), Baihui (GV 20) and Yintang (EX-HN3) plus ear-acupuncture, Prozac group (P., 176 cases) by oral administration of Prozac, and Non-acupoint needling group (NAN, 88 cases) by acupuncture at non-acupoints as acupuncture placebo. Self-rating Depression Scale (SDS) was examined before treatment, and one month, two and three months after treatment respectively to evaluate therapeutic effect, and Rating Scale for Side Effects (SERS) was used to evaluate the safety.ResultsAfter one month of treatment, SDS scores in Acup. Group were significantly lower than that in P. Group (P<0.05) and than that in NAN Group (P<0.01), and SDS scores in P. Group were lower than that in NAN Group (P<0.05), showing the SDS scores in Acup. Group <P. Group <NAN Group. After 2 months of treatment, SDS scores in Acup. Group were also significantly lower than that in P. Group (P<0.01) and than that in NAN Group (P<0.01), and SDS scores in P. Group were also lower than that in NAN Group (P<0.05), showing the SDS scores in Acup. Group <P. Group <NAN Group. After 3 months of treatment, SDS scores in Acup. Group were also significantly lower than that in P. Group (P<0.01) and than that in NAN Group (P<0.01), and SDS scores in P. Group were also lower than that in NAN Group (P<0.01), showing the SDS score in Acup. Group <P. Group <NAN Group. After treatment, SERS scores were 0.16±0.95, 6.51±5.09 and 0.23±1.36 in Acup. Group, P. Group and NAN Group respectively. A significant difference existed between Acup. Group and P. Group (P<0.05), but no significant difference between Acup. Group and NAN Group (P>0.05), showing the SERS scores in Acup. Group <NAN Group <P. Group. No side effect was found in Acup. and NAN groups.ConclusionThe therapeutic effect of acupuncture on depressive neurosis is better than or similar to that of Prozac but with less side effect

    Intrahepatic HBV DNA as a predictor of antivirus treatment efficacy in HBeAg-positive chronic hepatitis B patients

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    AIM: To evaluate the effect of antiviral agents on intrahepatic HBV DNA in HBeAg-positive chronic hepatitis B patients. METHODS: Seventy-one patients received treatment with lamivudine, interferon alpha (IFN-alpha 2b) or sequential therapy with lamivudine-IFN-alpha 2b for 48 wk. All subjects were followed up for 24 wk. Serum and intrahepatic HBV DNA were measured quantitatively by PCR. HBV genotypes were analyzed by PCR-RFLP. RESULTS: At the end of treatment, the intrahepatic HBV DNA level in 71 patients decreased from a mean of (6.1 +/- 1.0) log10 to (4.9 +/- 1.4) log10. Further, a larger decrease was seen in the intrahepatic HBV DNA level in patients with HBeAg seroconversion. Intrahepatic HBV DNA level (before and after treatment) was not significantly affected by the patients' HBV genotype, or by the probability of virological flare after treatment. CONCLUSION: Intrahepatic HBV DNA can be effectively lowered by antiviral agents and is a significant marker for monitoring antivirus treatment. Low intrahepatic HBV DNA level may achieve better efficacy of antivirus treatment

    Control of the dipole layer of polar organic molecules adsorbed on metal surfaces via different charge-transfer channels

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    Organic molecules with a permanent electric dipole moment have been widely used as a template for further growth of molecular layers in device structures. Key properties of the resulting organic films such as energy level alignment (ELA), work function, and injection/collection barrier are linked to the magnitude and direction of the dipole moment at the interface. Using angle-resolved photoemission spectroscopy (ARPES), we have systematically investigated the coverage-dependent work function and spectral line shapes of occupied molecular energy states (MES) of chloroaluminium-phthalocyanine (ClAlPc) grown on Ag(111). We demonstrate that the dipole orientation of the first ClAlPc layer can be controlled by adjusting the deposition rate and post annealing conditions; the ELA at the interface differs by ~0.4 eV between the Cl-up and -down configurations of the adsorbed ClAlPc molecules. These observations are rationalized by density-functional-theory (DFT) calculations based on a realistic model of the ClAlPc/Ag(111) interface, which reveal that the different orientations of the ClAlPc dipole layer lead to different charge-transfer channels between the adsorbed ClAlPc and Ag(111) substrate. Our findings provide a useful framework towards method development for ELA tuning

    Effect of Garlic Juice on Quality Changes of Oyster (Crassostrea Belcheri) Meat During Chilled Storage

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    Surat-thani oyster, a big and thin-shell bivalve mollusks, has been registered as Geographical Indicators, GI, as its good taste and delicacy as well as nutritious. Eaten style is raw then there is high risk to face with some disease as oyster is filter feeder. Physical, chemical, microbiological and sensory qualities after the oyster meat treated with the garlic juice at 0, 2 and 3 ml, respectively were monitored. Though initial pH of the control, untreated with garlic juice, was higher compared with the sample treated with 3 ml garlic juice, pH of it (control) was significantly lower (p5) at the end of the storag

    A multigene phylogeny toward a new phylogenetic classification of Leotiomycetes

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    Fungi in the class Leotiomycetes are ecologically diverse, including mycorrhizas, endophytes of roots and leaves, plant pathogens, aquatic and aero-aquatic hyphomycetes, mammalian pathogens, and saprobes. These fungi are commonly detected in cultures from diseased tissue and from environmental DNA extracts. The identification of specimens from such character-poor samples increasingly relies on DNA sequencing. However, the current classification of Leotiomycetes is still largely based on morphologically defined taxa, especially at higher taxonomic levels. Consequently, the formal Leotiomycetes classification is frequently poorly congruent with the relationships suggested by DNA sequencing studies. Previous class-wide phylogenies of Leotiomycetes have been based on ribosomal DNA markers, with most of the published multi-gene studies being focussed on particular genera or families. In this paper we collate data available from specimens representing both sexual and asexual morphs from across the genetic breadth of the class, with a focus on generic type species, to present a phylogeny based on up to 15 concatenated genes across 279 specimens. Included in the dataset are genes that were extracted from 72 of the genomes available for the class, including 10 new genomes released with this study. To test the statistical support for the deepest branches in the phylogeny, an additional phylogeny based on 3156 genes from 51 selected genomes is also presented. To fill some of the taxonomic gaps in the 15-gene phylogeny, we further present an ITS gene tree, particularly targeting ex-type specimens of generic type species. A small number of novel taxa are proposed: Marthamycetales ord. nov., and Drepanopezizaceae and Mniaeciaceae fams. nov. The formal taxonomic changes are limited in part because of the ad hoc nature of taxon and specimen selection, based purely on the availability of data. The phylogeny constitutes a framework for enabling future taxonomically targeted studies using deliberate specimen selection. Such studies will ideally include designation of epitypes for the type species of those genera for which DNA is not able to be extracted from the original type specimen, and consideration of morphological characters whenever genetically defined clades are recognized as formal taxa within a classification
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