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Pathogenic Escherichia coli poses a serious threat to global public health and is especially dangerous with the increase of antibiotic resistance. beta-Glucuronidase (GUS) and some other glycosidases can serve as useful biomarkers...
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Pathogenic Escherichia coli poses a serious threat to global public health and is especially dangerous with the increase of antibiotic resistance. beta-Glucuronidase (GUS) and some other glycosidases can serve as useful biomarkers or indicators for the detection of E. coli. The probes made up of a glycosyl residue (recognition group), a label or reporter group, and a linkage that is generally a direct glycosidic bond, are powerful analytical tools. Upon hydrolysis of the glycosidic linkages by the corresponding glycosidases, these probes irreversibly release detectable labels or reporter molecules. A variety of such glycosidase probes have been developed and applied for the detection ofE. coli or the development of various corresponding detection methods. This paper provides an overview of recent advances in this field, covering the development and applications of chromogenic, fluorogenic, luminogenic, and electrochemical glycosidase substrates. The challenges and opportunities in the probe development for detection ofE. coli are also discussed.
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Although glycopeptide antibiotics (GPAs), including vancomycin and teicoplanin, represent the most important class of anti-infective agents in the treatment of serious Gram-positive bacterial infections, their usefulness is threat...
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Although glycopeptide antibiotics (GPAs), including vancomycin and teicoplanin, represent the most important class of anti-infective agents in the treatment of serious Gram-positive bacterial infections, their usefulness is threatened by the emergence of resistant strains. GPAs are complex natural products consisting of a heptapeptide skeleton assembled via nonribosomal peptide synthesis and constrained through multiple crosslinks, with diversity resulting from enzymatic modifications by a variety of tailoring enzymes, which can be used to produce GPA analogues that could overcome antibiotic resistance. GPA-modifying sulfo-transferases are promising tools for generating the unique derivatives. Despite significant sequence and structural similarities, these sulfotransferases modify distinct side chains on the GPA scaffold. To provide insight into the spatial diversity of modifications, we have determined the crystal structure of the ternary complex of bacterial sulfotransferase StaL with the cofactor product 3-phosphoadenosine 5-phosphate and desulfo-A47934 aglycone substrate. Desulfo-A47934 binds with the hydroxyl group on the 4-hydroxyphenylglycine in residue t directed toward the 3-phosphoadenosine 5'-phosphate and hydrogen-bonded to the catalytic His67. Homodimeric StaL can accommodate GPA substrate in only one of the two active sites because of potential steric clashes. Importantly, the aglycone substrate demonstrates a flattened conformation, in contrast to the cup-shaped structures observed previously. Analysis of the conformations of this scaffold showed that despite the apparent rigidity due to crosslinking between the side chains, the aglycone scaffold displays substantial flexibility, important for enzymatic modifications by the GPA-tai-loring enzymes. We also discuss the potential of using the current structural information in generating unique GPA derivatives.
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Half-metallic MnAs and MnP layers were grown on GaAs substrates by the laser sputtering of ametal Mn target in a hydrogen and arsine (phosphine) flow. The effect of the arsine concentration in the gas-carrier and the substrate tem...
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Half-metallic MnAs and MnP layers were grown on GaAs substrates by the laser sputtering of ametal Mn target in a hydrogen and arsine (phosphine) flow. The effect of the arsine concentration in the gas-carrier and the substrate temperature ( Tg = 300-450°C) on the crystal structure and electrical and magneticproperties were determined. It was shown that MnP samples grown at T_g≥400°C exhibit ferromagnetic prop-erties up to 300 K, according to Hall effect measurements
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In the present study, effect of different substrates on mycelial growth and yield of Volvariella diplasia was evaluated. Volvariella diplasia, the paddy straw mushroom, is worldwide one of the most widely cultivated mushrooms. Cer...
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In the present study, effect of different substrates on mycelial growth and yield of Volvariella diplasia was evaluated. Volvariella diplasia, the paddy straw mushroom, is worldwide one of the most widely cultivated mushrooms. Cereals are the most popular basal ingredient used in synthetic substrate formulation for producing paddy straw mushroom spawn. However, the present work evaluates the best and cheap substrate for spawn culture and mushroom production. Paddy straw mushroom was cultivated on various types of cereals (Wheat, Maize, Ragi, Jowar, Bajra) and pulses (Bengal gram, Green gram). Cultivation on Bajra resulted in significantly faster mycelial growth as compared to other substrates followed by Jowar. With respect to fructification, culture on wheat shows highest production. The lowest biological and economical yields were found when the culture was on bajra. Biological efficiency and biological yield were highest with culture on wheat. The above findings reveal an opportunity for commercial implication of paddy straw mushroom especially Volvariella diplasia for utilization of different feasible and cheap substrates.
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This technical note describes the transfer of continuous, single-layer, pristine graphene to standard Quantifoil TEM grids. We compare the transmission properties of pristine graphene substrates to those of graphene oxide and thin...
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This technical note describes the transfer of continuous, single-layer, pristine graphene to standard Quantifoil TEM grids. We compare the transmission properties of pristine graphene substrates to those of graphene oxide and thin amorphous carbon substrates. Positively stained DNA imaged across amorphous carbon is typically indiscernible and requires metal shadowing for sufficient contrast. However, in a practical illustration of the new substrates properties, positively stained DNA is imaged across pristine graphene in striking contrast without the need of metal shadowing. We go onto discuss technical considerations and the potential applications of pristine graphene substrates as well as their ongoing development
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In this letter, the variation in the key RF performance parameters of MOSFETs in the presence of the substrate digital noise coupling is investigated. The parameters, including $f_{T}$ and $f_{max}$ , showed substantial change up...
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In this letter, the variation in the key RF performance parameters of MOSFETs in the presence of the substrate digital noise coupling is investigated. The parameters, including $f_{T}$ and $f_{max}$ , showed substantial change up to ${sim}20hbox{%}$ with realistic level of noise injection. It is shown that such change in the RF performance with the noise injection is due to the threshold voltage $(V_{T})$ variation. The observed $V_{T}$ variation is attributed to the virtual body effect due to the substrate potential fluctuation by the coupled substrate digital noise.
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Ellenberg indicator values (EIVs) describe the realized niche of species and habitat parameters, and are commonly used for vascular plants, bryophytes, and lichens. We provide a methodology for EIVs and an EIV list for nearly 650 ...
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Ellenberg indicator values (EIVs) describe the realized niche of species and habitat parameters, and are commonly used for vascular plants, bryophytes, and lichens. We provide a methodology for EIVs and an EIV list for nearly 650 species of macromycetes. We propose a new EIV scale, namely substrate openness (0). We also give the results of two applications and compare EIV values related to the Red List classification with those related to lifestyle classification. Mycorrhizal species on average have higher demands on substrate openness and are less tolerant of high nutrient levels than saprotrophic or parasitic species. Critically endangered species have on average distinctly higher demands on openness of habitat and substrate than not threatened or less strongly threatened species, which in turn have higher demands for nutrient availability. This pattern clearly highlights the points of threat for many macromycete species. (C) 2016 Elsevier Ltd and British Mycological Society. All rights reserved.
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We report studies of preimplantation human embryo development that correlate time-lapse image analysis and gene expression profiling. By examining a large set of zygotes from in vitro fertilization (IVF), we find that success in p...
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We report studies of preimplantation human embryo development that correlate time-lapse image analysis and gene expression profiling. By examining a large set of zygotes from in vitro fertilization (IVF), we find that success in progression to the blastocyst stage can be predicted with >93% sensitivity and specificity by measuring three dynamic, noninvasive imaging parameters by day 2 after fertilization, before embryonic genome activation (EGA). These parameters can be reliably monitored by automated image analysis, confirming that successful development follows a set of carefully orchestrated and predictable events. Moreover, we show that imaging phenotypes reflect molecular programs of the embryo and of individual blastomeres. Single-cell gene expression analysis reveals that blastomeres develop cell autonomously, with some cells advancing to EGA and others arresting. These studies indicate that success and failure in human embryo development is largely determined before EGA. Our methods and algorithms may provide an approach for early diagnosis of embryo potential in assisted reproduction.
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We report studies of preimplantation human embryo development that correlate time-lapse image analysis and gene expression profiling. By examining a large set of zygotes from in vitro fertilization (IVF), we find that success in p...
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We report studies of preimplantation human embryo development that correlate time-lapse image analysis and gene expression profiling. By examining a large set of zygotes from in vitro fertilization (IVF), we find that success in progression to the blastocyst stage can be predicted with >93% sensitivity and specificity by measuring three dynamic, noninvasive imaging parameters by day 2 after fertilization, before embryonic genome activation (EGA). These parameters can be reliably monitored by automated image analysis, confirming that successful development follows a set of carefully orchestrated and predictable events. Moreover, we show that imaging phenotypes reflect molecular programs of the embryo and of individual blastomeres. Single-cell gene expression analysis reveals that blastomeres develop cell autonomously, with some cells advancing to EGA and others arresting. These studies indicate that success and failure in human embryo development is largely determined before EGA. Our methods and algorithms may provide an approach for early diagnosis of embryo potential in assisted reproduction.
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Substrate materials have a significant influence on the coating properties, especially on the adhesion of coating to substrate. Therefore, the understanding of the substrate materials effect on deposited coatings will lead to a be...
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Substrate materials have a significant influence on the coating properties, especially on the adhesion of coating to substrate. Therefore, the understanding of the substrate materials effect on deposited coatings will lead to a better performance of the coated cutting tools. In this investigation, the TiAlN-(TiAlN/CrAlSiN)-TiAlN multiple coatings have been prepared by arc ion plating technology on cermet, cemented carbide and high-speed steel substrates, respectively. The effects of substrate materials on microstructure, hardness, adhesion strength as well as tribological properties of the as-deposited coatings were investigated. The results show that the TiAlN-(TiAlN/ CrAlSiN)-TiAlN multiple coatings on all substrates exhibit a single (200) preferred fcc-CrN structure with columnar grain morphology. With the finest grains of 16.2 rim and the strong solid solution strengthening effect, the coating deposited on the cermet substrate possesses the highest hardness. However, the TiAlN-(TiAlN/CrAlSiN)-TiAlN multiple coating obtained on the cemented carbide substrate has the highest adhesion of 95 N due to the slightly lower thermal expansion coefficient of the cemented carbide substrate than the inner TiAlN layer as well as the small hardness difference between the cemented carbide substrate and the coating. Owing to the low friction coefficient and high hardness, the TiAlN-(TiAlN/CrAlSiN)-TiAlN multiple coating prepared on the cemented carbide substrate exhibits the best wear resistance. Besides, the wear mechanism of the TiAlN(TiAlN/CrAlSiN)-TiAlN multiple coatings is the combination of abrasive, oxidative and adhesive wear, which is little affected by the substrate materials.
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