Enhancing the activity of metal-organic nanosheets for oxygen evolution reaction by substituent effects.

Rational designing and synthesizing highly efficient oxygen evolution reaction (OER) electrocatalyst plays a key role in energy conversion. However, due to the numerous factors affecting the activity of electrocatalysis, the understanding of their catalytic mechanism is insufficient, and challenges still exist. Herein, the organic group of the metal-organic nanosheets electrocatalyst was replaced by NH2 to CH3 to controllable regulate the catalytic performance of OER, corresponding to the overpotential of OER reducing from 385 mV to 318 mV at 10 mA cm-2, superior to the commercial precious metal based catalyst RuO2. Furthermore, combining the density functional theory (DFT) and electron localization function (ELF) indicates that the type of ligands group can indirectly modulate the electronic structure of metal catalytic center and the degree of electronic localization of the metal-organic nanosheets catalysts, resulting in the change in electrocatalytic activity. This simple catalytic model is more favorable to investigate the catalytic mechanism, providing a new strategy for the development of efficient electrocatalyst.

Endo-siRNAs regulate early embryonic development by inhibiting transcription of long terminal repeat sequence in pig†.

Activity of some endogenous retroviruses (ERVs) has been proven to be important for development of early mammalian embryo. However, abnormal activation of ERVs can also cause genetic diseases due to their ability to retrotranspose, so the regulatory mechanism to limit transcription of ERVs needs to be clarified. Endogenous small interfering RNA (endo-siRNA) has been reported to protect cells against transposable elements (TEs). Here, we determined the role of ERVs long terminal repeat sequences (LTRs) derived endo-siRNAs (LTR-siRNAs) on inhibition of the activity of ERVs during early embryonic development in pig. Seven most highly expressed LTR-siRNAs were identified in porcine zygote by high-throughput small RNA sequencing. We verified that the biogenesis of the LTR-siRNAs was DICER-dependent and they were generated from double-stranded RNA (dsRNA) formed by sense and antisense transcripts of LTRs. And, the expression of sense and antisense of LTRs might be due to the loss of DNA methylation at some LTR loci. Furthermore, we showed that the LTR-siRNAs could regulate early embryonic development by repression of LTRs expression at a post-transcriptional level. So, we propose here, during early embryonic development when epigenetic reprogramming occurs, the endo-siRNA pathway acts as a sophisticated balance of regulatory mechanism for ERV activity.

Sporolactobacillus pectinivorans sp. nov., an anaerobic bacterium isolated from spoiled jelly.

A Gram-positive-staining, endospore-forming, facultatively anaerobic, lactic-acid-producing bacterium, strain GD201205T, was isolated from spoiled jelly in China. Strain GD201205T fermented glucose, fructose, mannose, sucrose, raffinose and turanose, but negative for nitrate reduction, catalase and oxidase. The predominant fatty acids of the strain were anteiso-C17 : 0 and anteiso-C15 : 0. Whole-cell hydrolysates contained glycine and alanine with meso-iaminopimelic acid as the diagnostic diamino acid. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, glycolipid 1 and glycolipid 2. The DNA G+C content of strain GD201205T was 48.7 mol%. 16S rRNA gene sequence analysis indicated that the strain belonged to the genus Sporolactobacillus and was most closely related to Sporolactobacillus vineaeKCTC 5376T and Sporolactobacillus putidusJCM 15325T with 16S rRNA gene sequence similarities of 97.5 and 96.9 %, respectively. Levels of DNA-DNA relatedness between strain GD201205T and Sporolactobacillus vineaeKCTC 5376Tand Sporolactobacillus putidusJCM 15325T were 29.2 and 47.6 %, respectively. Phylogenetic analysis based on the 16S rRNA gene and gyrB gene revealed that strain GD201205T was clearly distinct from all related species of the genus Sporolactobacillus. On the basis of the phylogenetic, chemotaxonomic and phenotypic evidence given in this study, strain GD201205T should be classified as a representative of a novel species of the genus Sporolactobacillus for which the name Sporolactobacillus pectinivorans is proposed. The type strain is GD201205T (=CICC 23867T=KCTC 15488T).

Investigation of the status of interhospital transport of critically ill pediatric patients.

BACKGROUND: With the unequal distribution of medical resources in developing countries, critically ill children need to be transferred to tertiary hospitals from primary hospitals with limited resources. Although a large number of critically ill children are transferred each day in China, the standard process of inter-hospital transport is not formulated. METHODS: We retrospectively analyzed the data collected during transport. A total number of 9231 patients (≤14 years) who had been transferred to the Hunan Children's Hospital by a specialized team from primary hospitals from January 1, 2009 to June 30, 2012 were included in the study. RESULTS: Nearly half of the critically ill children were neonates (48.72%) and two thirds of the children were suffering from respiratory, neurological and cardiac diseases. Multivariate adjusted odds ratios (OR) and 95% confidence intervals (CI) were calculated using unconditional logistic regression. Mobilization time in non-working hours was longer than the working hours (OR=1.186, 95% CI=1.059-1.329). Our study showed that mobilization time for neonates was shorter than that for older children (OR=0.801, 95% CI=0.692-0.928). The mobilization time of referral cases was shorter in areas within a radius of 50 km than in those within a radius of over 250 km (OR=0.427, 95% CI=0.350-0.521). Referred patients in summer needed a significantly shorter mobilization time than in winter (OR=0.705, 95% CI=0.616-0.806). CONCLUSION: Standardized processes and guidelines for inter-hospital transport would be essential to ensure effective transport of patients and reduce the mobilization activation time.

p-Toluenesulfonic acid mediated 1,3-dipolar cycloaddition of nitroolefins with NaN3 for synthesis of 4-aryl-NH-1,2,3-triazoles.

A p-TsOH-mediated 1,3-dipolar cycloaddition of nitroolefins and sodium azide for the synthesis of 4-aryl-NH-1,2,3-triazoles has been developed. p-TsOH was discovered as a vital additive in this type of 1,3-dipolar cycloaddition. This novel cycloaddition reaction is a good method for the rapid synthesis of valuable 4-aryl-NH-1,2,3-triazoles in high yields.

A facile BPO-mediated ortho-hydroxylation and benzoylation of N-alkyl anilines for synthesis of 2-benzamidophenols.

A facile benzoyl peroxide (BPO) mediated ortho-hydroxylation and benzoylation of N-alkyl anilines for the synthesis of 2-benzamidophenols has been developed. The reaction tolerates a wide range of functional groups and is a good method for the straightforward synthesis of valuable 2-benzamidophenols in good yields under mild conditions.

[Adsorption behaviors of protonation modified chitosan and the analysis of spectra].

In order to improve adsorbing performance and stability of chitosan in acid simultaneously, cross-linking was employed after the protection of amino groups for improving its stability, then the protection of amino groups was removed and protonated to obtain high adsorption performance. With formaldehyde as amino-group protective agent and glutaraldehyde as cross-linking reagent, cross-linked chitosan (CCTS) was prepared by reversed phase suspension method in this paper, then it was protonated to make protonation modified chitosan adsorbent (P-CCTS). The adsorption performance of sulfate ion onto P-CCTS was firstly studied and investigated by static adsorption test. Elemental analysis by energy dispersive spectrometer of X-rays (EDS) and identifying of functional groups by Fourier transform infrared spectroscopy (FTIR) were used to analyze the preparation and adsorption of the adsorbent, and the reaction mechanism of cross-linking and adsorption was investigated. The results show that the adsorption performance of P-CCTS towards sulfate ion is 10 times higher than that of unmodified chitosan, and formaldehyde and glutaraldehyde mainly react with amino (-NH2) and part of hydroxy (C6-OH) of chitosn. A salt of chitosan protonated amino chlorine was formed through the process of the protonation of amino, the adsorption of sulfate ion mainly occurs on the protonated amino on which ion exchange happened between chlorine ion and sulfate ion.

Oxidation of 2-arylindoles for synthesis of 2-arylbenzoxazinones with oxone as the sole oxidant.

A novel and efficient method for the oxidation of 2-arylindoles to synthesize 2-arylbenzoxazinones utilizing oxone as the sole oxidant has been developed. The reaction tolerates a wide range of functional groups and allows quick and atom-economical assembly of a variety of valuable 2-arylbenzoxazinones in high yields.

Antimycins A(19) and A(20), two new antimycins produced by marine actinomycete Streptomyces antibioticus H74-18.

Two new antimycin antibiotics; that is antimycins A(19) (1) and A(20) (2), were isolated from a cultured broth of marine actinomycete Streptomyces antibioticus H74-18 together with antimycins A(1a) (3a) and A(1b) (3b), A(2a) (4), A(3a) (5a) and A(3b) (5b). Their structures were determined by spectroscopic methods in combination with X-ray diffraction. Antimycin A(19) possessed a chiral acyl chain and an alkyl branch. The absolute configuration of chiral acyl chain in 1 was determined by X-ray diffraction analysis. Antimycin A(20) (2) has the shortest and simplest acetoxy acyl chain in the antimycins family. All the antimycins (1-5) showed potential antifungal activities against Candida albicans with MIC of about 5-10 µg ml(-1).

[Etiologic and molecular characteristics of Vibrio parahaemolyticus strains isolated from diarrheal patients in Shenzhen, in 2007 - 2008].

OBJECTIVE: To study the infection status and the molecular characteristics of Vibrio parahaemolyticus isolated from diarrheal patients in Shenzhen, in 2007 to 2008 and to provide evidence for the prevention and control of diarrheal diseases caused by Vibrio parahaemolyticus. METHODS: More than 80 fecal specimens from four sentinel surveillance hospitals were collected and cultured each month. A total of 361 isolates of Vibrio parahaemolyticus were sero-typed and examined by real-time PCR for the presence of two major virulence genes, tdh and trh. Of 361 strains, 60 O3: K6 strains isolated from six suspected outbreaks in August, 2007 and in September, 2008 were typed by pulsed-field gel electrophoresis (PFGE). RESULTS: 4384 stool samples were detected in four sentinel surveillance hospitals and with 361 Vibrio parahaemolyticus strains isolated that belonged to 28 serotypes. Serotype O3:K6, O4:K8 and O1:KUT accounted for 67.90%, 7.50% and 6.10%, respectively. Of 361 strains, 337 strains belonged to tdh+trh-, 11 strains were tdh-trh- and 13 strains were tdh+trh+. The most prevalent serotype which caused diarrheal diseases was tdh+trh in Shenzhen. The 60 isolates were discriminated into twenty different PFGE patterns, which belonged to three clones. Among the 60 isolates, most of the PFGE patterns of isolates from the suspected outbreak locations were identical and some strains isolated from different year were different. CONCLUSION: Vibrio parahaemolyticus isolates in Shenzhen were dominated by O3:K6 strains. Most of these isolates carried tdh gene and few carried trh gene. Meanwhile, the identical patterns of isolates from 6 suspected outbreaks locations demonstrated that Vibrio parahaemolyticus outbreaks occurred in July 2007 and in September 2008 in Shenzhen. However, the dominated strains' PFGE patterns were different each year, indicating that the sources of Vibrio parahaemolyticus had a multiplex nature and the multiplex sources such as water, sea food and pickled products should be integrated monitored. Laboratory based surveillance of diarrheal diseases could contribute in establishing early warning system for the better prevention and control of diarrheal diseases.

[Analysis of pulsed-field gel electrophoresis molecular subtyping of Shigella strains in Shenzhen].

OBJECTIVE: To analyze the genetic relations of Shigella isolated from Shenzhen in 2001-2006 and develop primary molecular subtyping surveillance network of Shigella. METHODS: Chromosomal DNAs from 55 isolated in agarose were digested with the restriction enzyme Xba I, and then were analyzed by pulsed-field gel electrophoresis. Pulsed-field gel electrophoresis (PFGE) patterns were clustered using BioNumerics software. RESULTS: All 41 distinctive PFGE patterns were identified among 55 strains. 32 strains belonged to one cluster. Differences were observed in other strains. CONCLUSION: Both genetic-related clones and non-related clones of Shigella existed in Shenzhen. The development of PFGE molecular subtyping surveillance network would contribute to the active surveillance, outbreak investigation and source tracking for Shigellosis.

Influence of surface microroughness by plasma deposition and chemical erosion followed by TiO2 coating upon anticoagulation, hydrophilicity, and corrosion resistance of NiTi alloy stent.

Two different surface modification techniques were used to change the surface morphology and roughness of stents at the micrometer level, and eventually improve their surface adhesion properties with respect to endothelial cells. One was chemical erosion followed by sol-gel TiO(2) coating, and the other was low temperature gas plasma deposition. After surface modification, the biocompatibility including the anticoagulation properties, hydrophilicity, and corrosion resistance of these stents was evaluated. It was found that both techniques could change the surface morphology of the stents with microroughness. In comparison with the control, the treated NiTi alloy intravascular stents showed increased surface hydrophilicity and enhanced anticoagulation properties. However, the corrosion properties of the stents were not improved significantly.

[Application of pulsed-field gel electrophoresis in a food-borne outbreak of Salmonella serotype Muenchen infection].

OBJECTIVE: To investigate the application of pulsed-field gel electrophoresis (PFGE) in food-borne outbreak. METHODS: Pathogens were isolated and further characteristics identified by traditional methods. The strains isolated were carried out with molecular typing with using PFGE. PFGE was performed by Laboratory Directions for molecular subtyping of Salmonella by PFGE (CDC, USA) and the results of PFGE were analyzed by BioNumerics soft. RESULTS: Totally 14 Salmonella serotype Muenchen strains were isolated from 19 patients, 3 of 9 suspicious foods were positive for S. muenchen and 7 strains were isolated from 18 cooks. The biochemistry characterization and antimicrobial susceptibility of all the strains isolated were the same. 23 S. muenchen isolates were all shown indistinguishable by PFGE. CONCLUSION: PFGE should play a key role in identifying the outbreak-associated isolates and distinguishing them from unrelated sporadic isolates. It might also demonstrate that the genetic fingerprints of serotype Muenchen isolates derived from patients were indistinguishable from those derived from drinks. PFGE might provide precise information on bacterial food-borne pathogens, promptly identify the source of infection, and effectively prevent from spreading. It should be one of the early warning method on controlling outbreak of the food-borne disease.

[Molecular subtyping of Vibrio cholerae isolates by pulsed-field gel electrophoresis in Shenzhen from 1993].

OBJECTIVE: To determine the genetic relationships between different Vibrio cholerae isolates in Shenzhen from 1993 to 2002. METHODS: Chromosomal DNA from 60 isolates was digested in seakem gold agrose with restriction enzyme Not I and plugs were then analyzed by pulsed-field gel electrophoresis. Pulsed-field gel electrophoresis (PFGE) patterns of V. cholerae isolates were clustered using BioNumerics software. RESULTS: 39 distinctive PFGE patterns were identified with each pattern having 20 to 30 bands. Most PFGE patterns were divided into cluster A or cluster B. CONCLUSION: The closely related pandemic clone clusters of V. cholerae strains did exist in Shenzhen. PFGE of V. cholerae could be used for active surveillance and tracking for cholerae.

[Preliminary study of the ultrasonic measurement of thickness of skin in children].

OBJECTIVE: To collect the data of measuring skin thickness of children of both genders of different ages and parts of body with non-invasive high-frequency ultrasound method. METHODS: Two hundred and twenty-one children from 1 to 18 years of age,without systemic disease or injury in skin, were enrolled in the study and divided into 4 groups: i.e., infant group (112 years of age), pre-school age group (3-6 years of age), school age group (7-12 years for boys and 7-11 years for girls), adolescent age group (13-18 years for boys and 12-18 years for girls), and each group was subdivided into 2 groups according to the gender. The skin thicknesses of children in cheek, chest, abdomen, forearms, fundament and thigh was respectively measured by 13 MHz high-frequency ultrasound. RESULTS: The region with thinnest skin in children was the cheek, and the thickest was the back and buttock. (1) There were no significant differences in thickness of skin in the same region between genders and also among different age groups (P > 0.05). (2) There were also no obvious differences of thickness of the dermis and the whole skin in the same region between male and female, or among infants, pre-school age and school age groups (P > 0.05). In adolescent group, the average thickness of dermis in male was (1.16 +/- 0.04 ) - (1.98 +/- 0.47) mm, the average whole thickness of skin in male was (1.27 +/- 0.12) - (2.20 +/- 0.45) mm, while those of female were (1.00 +/- 0.18) - (1.60 +/- 0.30) mm and (1.10 +/- 0.17) - (1.83 +/- 0.29) mm (P < 0.05). CONCLUSION: It is reliable to measure the skin thickness by 13MHz ultrasound as a non-invasive method. The main factor which determined the thickness of the skin is dermal thickness, especially in males. The significant differences of skin thickness among cheek, back and buttock provide the basis for us to choose the appropriate thickness of skin grafts harvested from different body parts.

[Study on surface modification and biocompatibility of NiTi alloy intravascular stents].

This paper introduces the surface modification of NiTi alloy intravascular stents for roughness by chemical erosion and plasma deposition technology. The stent which had been granulated with chemical erosion was treated with TiO2 film prepared with Gel-sol. The study on the biocompatibility of the modified stent by the above two ways shows that the modified stent is rougher, and its anticoagulation and hydrophilicity are improved. However, the capability of erosion resistance is not enhanced significantly.

[Analysis of antimicrobial resistance of clinical isolates of Escherichia coli].

OBJECTIVE: To analyze the antimicrobial resistance of clinical Escherichia coli and the situations of ESBLs-producing clinical isolates of Escherichia coli for guiding the rational use of antibiotics to control infections. METHODS: Identification, susceptibility tests of 20 antibiotics and ESBLs detection tests were performed using Microscan WalkAway40. RESULTS: The resistant rates to 14 antibiotics were higher than 50%. The clinical isolates of Escherichia coli were highly resistant to ampicillin, but were highly susceptible to imipenem. The number of antibiotics encountering resistance of clinical isolates of Escherichia coli ranged from 1 to 19; 93% of the isolates were multidrug-resistant; 49% of the isolates produced ESBLs. The resistant rates of ESBLs-producing isolates to 14 antibiotics were higher than those of non-ESBLs-producing isolates. CONCLUSION: The antimicrobial resistance of clinical isolates of Escherichia coli, especially that of multidrug-resistant isolates, is highly prevalent. So doctors must pay great attention to the resistance pattern and the distribution of Escherichia coli in the hospitals and localities where they work. Rational use of antibiotics should be emphasized for reducing the pressure of screening to control the prevalence of antimicrobial resistance.