Graphite Carbon-Supported Mo2C Nanocomposites by a Single-Step Solid State Reaction for Electrochemical Oxygen Reduction

Novel graphite-molybdenum carbide nanocomposites (G-Mo₂C) are synthesized by a typical solid state reaction with melamine and MoO₃ as precursors under inert atmosphere. The characterization results indicate that G-Mo₂C composites are composed of high crystallization and purity of Mo₂C and few layers of graphite carbon. Mo₂C nanoparticles with sizes ranging from 5 to 50 nm are uniformly supported by surrounding graphite layers. It is believed that Mo atom resulting from the reduction of MoO₃ is beneficial to the immobilization of graphite carbon. Moreover, the electrocatalytic performances of G-Mo₂C for ORR in alkaline medium are investigated by cyclic voltammetry (CV), rotating disk electrode (RDE) and chronoamperometry test with 3M methanol. The results show that G-Mo₂C has a considerable catalytic activity and superior methanol tolerance performance for the oxygen reduction reaction (ORR) benefiting from the chemical interaction between the carbide nanoparticles and graphite carbon.

Novel VN/C nanocomposites as methanol-tolerant oxygen reduction electrocatalyst in alkaline electrolyte

A novel VN/C nanostructure consisting of VN nanoparticles and graphite-dominant carbon layers is synthesized by nitridation of V₂O₅ using melamine as reductant under inert atmosphere. High crystalline VN nanoparticles are observed to be uniformly distributed in carbon layers with an average size of ca13.45 nm. Moreover, the electrocatalytic performance of VN/C towards oxygen reduction reaction (ORR) in alkaline electrolyte is fascinating. The results show that VN/C has a considerable ORR activity, including a 75 percent value of the diffusion-limited current density and a 0.11 V smaller value about the onset potential with respect to Pt/C catalyst. Moreover, the excellent methanol-tolerance performance of VN/C has also been verified with 3 M methanol. Combined with the competitive prices, this VN/C nanocomposite can serve as an appropriate non-precious methanol-tolerant ORR catalyst for alkaline fuel cells.

Time domain simulations of preliminary breakdown pulses in natural lightning

Lightning discharge is a complicated process with relevant physical scales spanning many orders of magnitude. In an effort to understand the electrodynamics of lightning and connect physical properties of the channel to observed behavior, we construct a simulation of charge and current flow on a narrow conducting channel embedded in three-dimensional space with the time domain electric field integral equation, the method of moments, and the thin-wire approximation. The method includes approximate treatment of resistance evolution due to lightning channel heating and the corona sheath of charge surrounding the lightning channel. Focusing our attention on preliminary breakdown in natural lightning by simulating stepwise channel extension with a simplified geometry, our simulation reproduces the broad features observed in data collected with the Huntsville Alabama Marx Meter Array. Some deviations in pulse shape details are evident, suggesting future work focusing on the detailed properties of the stepping mechanism.

KEY POINTS

Preliminary breakdown pulses can be reproduced by simulated channel extension Channel heating and corona sheath formation are crucial to proper pulse shape Extension processes and channel orientation significantly affect observations.

Ammonium increases Ca(2+) signalling and upregulates expression of Cav1.2 gene in astrocytes in primary cultures and in the in vivo brain

AIM

The primary aim of this study was to identify the effects of hyperammonaemia on functional expression of Cav1.2 L-type Ca(2+) channels in astroglia.

METHODS

Primary cultures of mouse astrocytes were used to study effects of chronic treatment (1-5 days) with ammonium chloride, at 1, 3 and 5 mm on depolarization-induced increases in free cytosolic Ca(2+) concentration ([Ca(2+)]i , measured with Fura-2 based microfluorimetry) in control conditions and following treatment with the L-type Ca(2+) channel inhibitor, nifedipine, or with ryanodine receptor inhibitor, ryanodine. Expression of Cav1.2 mRNA was identified with RT-PCR, whereas protein content was determined by Western blotting. Sustained hyperammonaemia in vivo was induced by daily injections of urease (33 units kg body weight(-1), i.p.) for 3 days.

RESULTS

Depolarization-induced [Ca(2+)]i transients sensitive to nifedipine (peak of the response) and to ryanodine (plateau phase) were significantly increased in astrocytes chronically exposed to ammonium. The ammonium-induced increase in Ca(2+) influx in astrocytes resulted from an upregulation of Cav1.2 channel's expression detected at mRNA and protein levels. Increase in Cav1.2 expression was prevented by ouabain antagonist canrenone. Similar upregulation of Cav1.2 gene expression was found in the brains of adult mice subjected to intraperitoneal injection of urease. In transgenic mice tagged with an astrocyte-specific or neurone-specific markers and treated with intraperitoneal injections of urease, the fluorescence-activated cell sorting of neurones and astrocytes demonstrated that Cav1.2 mRNA expression was upregulated in astrocytes, but not in neurones.

CONCLUSIONS

Ammonium-induced deregulation of astroglial Ca(2+) signalling, is, in part, associated with upregulation of Cav1.2 L-type calcium channels.

First Report of Powdery Mildew Podoshaera tridactyla on Prunus hypoleuca in China

Prunus hypoleuca (≡ Maddenia hypoleuca), a native plant in China, grows in the Qinling Mountains that lie at the intersection of several forest regions in north, central, and southwest China. In October 2013, P. hypoleuca suffering from heavy powdery mildew infections was found with approximately 75% of the plants affected. The powdery mildew at first appeared as circular to irregular white patches, which subsequently showed abundant hyphal growth on both sides of leaves, leading to the withering of the leaves. A voucher specimen was maintained in the Mycological Herbarium of Northwest A & F University (Accession No. HMNWAFU-CF 2013166). Hyphal appressoria were nipple-shaped or nearly absent. Conidiophores were cylindrical, measured 83 to 110 × 10 to 12.5 μm, and produced two to five immature conidia in chains with a crenate outline. Foot-cells of conidiophores were straight, cylindrical, and 28 to 62 × 7 to 10 μm. Conidia were hyaline, ellipsoid to ovate, and measured 20 to 32 × 14 to 21 μm (length/width ratio 1.4:1.8). Chasmothecia were scattered or gregarious, depressed globose, and 65 to 112 μm in diameter. Appendages, arising from the upper half of the chasmothecia, usually had two to four dichotomous branches, and were one to three and a half times as long as the chasmothecial diameter. A single ascus in a chasmothecium was subglobose or broadly ellipsoid-ovoid, measured 66 to 86 × 47 to 76 μm and contained six to eight ascospores. The ascospores were ellipsoid-ovoid and 15 to 27 × 12 to 18 μm. The fungus was identified as Podosphaera tridactyla based on its anamorph and teleomorph characteristics (1,2). To confirm the identification, 28S rDNA and the ITS region were amplified. The ITS5/P3 and then PM5/ITS4 primers were used to amplify the ITS region by nested PCR. The primers LSU1/LSU2 were used to amplify the 28S rDNA, and the cloned fragments were sequenced. The 28S rDNA and ITS region sequences were deposited in GenBank (Accession Nos. KJ879240 and KM213121). A GenBank BLAST search of two sequences revealed 99% identity with P. tridactyla infecting Prunus salicina Lindl. in Korea (3). Based on ITS and a 28S rDNA phylogenetic tree, the two sequences retrieved from the Chinese specimen clustered within a strongly supported clade (bootstrap value = 100%) with P. tridactyla (JQ517296 and AB022393, respectively). Cladistic trees were constructed using the neighbor-joining method with the Kimura two-parameter substitution model in MEGA 5.0. Branch robustness was assessed via bootstrap analysis with 1,000 replicates. Phylogenetic analysis data were in agreement with morphological characters (3). To our knowledge, this is the first report of powdery mildew caused by P. tridactyla on P. hypoleuca. While Koch's postulates have not been carried out because of the biotrophic nature of the pathogen, the present report serves as a novel resource in order to improve the understanding of the etiology and epidemiology of the powdery mildew (P. tridactyla) on P. hypoleuca. The occurrence of P. tridactyla, a common powdery mildew on Prunus s. lat., supports recently published results of phylogenetic analyses of the Prunus complex, indicating that Maddenia must be reduced to synonymy with Prunus (4). References: (1) U. Braun. Beih. Nova Hedwigia 89:1, 1987. (2) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No. 11. CBS, Utrecht, Netherlands, 2012. (3) S. C. Lee et al. Res. Plant Dis. 18:49, 2012. (4) J. Wen and W. T. Shi. PhytoKeys 17(2):39, 2012.

Cervical ripening agent dinoprostone for delivery induction in late pregnancy mothers: experiences of 685 cases

The failure of labor induction often requires following cesarean section and suffering of patients. Cervical ripening is therefore critical in clinical care of pregnant mothers. The present study demonstrated the use of dinoprostone in cervical ripening for delivery induction in 685 cases of pregnancy mothers. The authors conclude that dinoprostone is a very useful and safe drug for delivery induction. The combined use of oxytocin and careful monitoring of all body symptoms are important for the clinical safety.

Connexin26 (GJB2) deficiency reduces active cochlear amplification leading to late-onset hearing loss

Connexin26 (Cx26, GJB2) mutations account for >50% of nonsyndromic hearing loss. The deafness is not always congenital. A large group of these patients (∼30%) demonstrate a late-onset hearing loss, starting in childhood. They have normal hearing early in life and are therefore good candidates for applying protective and therapeutic interventions. However, the underlying deafness mechanism is unclear. In this study, we used a time-controlled, inducible gene knockout technique to knockout Cx26 expression in the cochlea after birth. We found that deletion of Cx26 after postnatal day 5 (P5) in mice could lead to late-onset hearing loss. Similar to clinical observations, the mice demonstrated progressive, mild to moderate hearing loss. The hearing loss initiated at high frequencies and then extended to the middle- and low-frequency range. The cochlea showed normal development and had no apparent hair cell loss. However, distortion product otoacoustic emission (DPOAE) was reduced. The reduction was also progressive and large at high-frequencies. Consistent with DPOAE reduction, we found that outer hair cell electromotility-associated nonlinear capacitance was shifted to the right and the slope of voltage dependence was reduced. The endocochlear potential was reduced in Cx26 conditional knockout (cKO) mice but the reduction was not associated with progressive hearing loss. These data suggest that Cx26 deficiency may impair active cochlear amplification leading to late-onset hearing loss. Our study also helps develop newer protective and therapeutic interventions to this common nonsyndromic hearing loss.

[Study on of the current status of volatile organic compounds pollution in typical rural drinking water and the relationship between its concentration and health of the population, in Huai'an, Jiangsu]

OBJECTIVE

This study was to understand the status of pollution on drinking water, by volatile organic compounds (VOCs), among rural residents living in the basin of Huaihe River. Relationship between the morbidity, morbidity of cancers and VOCs were also explored.

METHODS

28 villages were chosen from Xuyi,Jinhu, Chuzhou along the Huaihe River, with water samples collected from ditch pond water, shallow wells, deep wells in November-December 2010. VOCs indicators were evaluated according to the Standard Quality GB 5749-2006 for Drinking Water.

RESULTS

Methylene chloride, chloroform, benzene and carbon tetrachloride were all detected in 76 water samples. The rates of chloroform, benzene, carbon tetrachloride which exceeding the quality standards were 3.95% , 21.05% and 22.37% , but no significant differences were found among these three water resources in chloroform, benzene or carbon tetrachloride. Results from the correlation analysis showed that benzene had positive correlation with tumor deaths (r = 0.24, P < 0.05). Results from the risk assessment on health showed that some chloroform, benzene, carbon tetrachloride products which were related to the risks of cancers were exceeding the acceptable ranges of risk, with the rates as 28.95%, 22.37% and 64.47% but with no significant differences among the three water resources (P > 0.05).

CONCLUSION

Drinking waters for rural residents along the Huaihe River were polluted while VOCs might have related to tumor incidence with potential impact and risk to the health of local residents.

Systematic review: faecal microbiota transplantation therapy for digestive and nondigestive disorders in adults and children

BACKGROUND

There has been growing interest in the use of faecal microbiota transplantation (FMT) for the treatment of gastrointestinal and nongastrointestinal diseases.

AIM

To review systematically the reported efficacy and safety of FMT in the management of gastrointestinal and nongastrointestinal disorders in adults and children.

METHODS

The systematic review followed Cochrane and PRISMA recommendations. Available articles were identified using three electronic databases in addition to hand searching and contacting experts. Inclusion criteria were any reports of FMT therapy written in English.

RESULTS

A total of 844 patients who had undergone FMT were identified from 67 published studies. The most common indications were refractory/relapsing Clostridium difficile infection (CDI) (76.3%) and inflammatory bowel disease (IBD) (13.2%). There has been only one placebo-controlled trial, a successful trial in 43 patients with recurrent CDI. Seven publications report FMT in paediatric patients with a total of 11 treated, 3 with chronic constipation and the remainder with recurrent CDI or ulcerative colitis (UC). 90.7% of patients with refractory/relapsing CDI were cured and 78.4% of patients with IBD were in remission after FMT. FMT therapy could also be effective in treatment of some nongastrointestinal disorders such as chronic fatigue syndrome. The only reported serious adverse event attributed to the therapy was a case of suspected peritonitis.

CONCLUSIONS

Although more controlled trials are needed, faecal microbiota transplantation therapy shows promise in both adults and children with gastrointestinal diseases such as CDI and IBD.

Surface characterization and osteoblast response to a functionally graded hydroxyapatite/fluoro-hydroxyapatite/titanium oxide coating on titanium surface by sol-gel method

OBJECTIVES

To improve efficacy of current titanium and its alloys, in bioactivity and speed of osseointegration, of orthopaedic implants.

MATERIALS AND METHODS

A novel triple-layered functional graded coating, consisting of a porous hydroxyapatite (HA) outermost layer, fluoro-HA (FHA) intermediate layer and titanium oxide (TiO2 ) innermost layer, was created on a titanium substrate by a multistep sol-gel method. X-ray diffraction analysis showed TiO2 anatase and apatite crystallization in the coating.

RESULTS

Morphological analysis performed by scanning electron microscopy showed excellent bonding between coating and substrate, with a thickness of ~2 μm. Scratch testing found favourable adhesion strength of the composite coating. In addition, optical microscope images suggested good biocompatibility. Considering thet in vitro cell response, osteoblasts on the coating exhibited higher cell proliferation and ALP activity compared to pure titanium and HA coating, and demonstrated excellent coating bioactivity.

CONCLUSIONS

Current results indicated that the novel TiO2 /FHA/HA coating has promising clinical applications in orthopaedic and dental implantation.

First Report of Powdery Mildew Caused by Podosphaera spiraeae on Japanese Spiraea in China

Japanese spiraea (Spiraea japonica L.f.), belonging to Rosaceae, is widely planted for its ornamental value in China. Since July 2011, powdery mildew infections on leaves and stems of Japanese spiraea have been noticed in some parks and gardens of Chengyang District in Qingdao City, China (GPS coordinates 36°31'04.22″ N, 120°39'41.92″ E). Symptoms first appeared as white spots covered with mycelium on both side of the leaves and young stems. As the disease progressed, abundant mycelial growth covered the whole shoots and caused growth reduction and leaf distortion with or without reddening. A voucher specimen was deposited in the herbarium of Qingdao Agricultural University (Accession No. HMQAU13013). Hyphae were flexuous to straight, branched, septate, 5 to 7 μm wide, and had nipple-shaped appressoria. Conidiophores arising from the upper surface of hyphal cells produced 2 to 5 immature conidia in chains with a crenate outline. Foot-cells of conidiophores were straight, 60 to 125 × 7 to 9 μm, and followed by 1 to 2 shorter cells. Conidia were ellipsoid-ovoid to doliiform, measured 25 to 32 × 12 to 15 μm with a length/width ratio of 1.8 to 2.6, and had distinct fibrosin bodies. Chasmothecia were not found. The structures and measurements were compatible with the anamorphic state of Podosphaera spiraeae (Sawada) U. Braun & S. Takam. as described before (1). The identity of HMQAU13013 was further confirmed by analysis of nucleotide sequences of the internal transcribed spacer (ITS) regions amplified using the primers ITS1/ITS4 (4). The resulting 564-bp sequence was deposited in GenBank (Accession No. KF500426). A GenBank BLAST search of complete ITS sequence showed 100% identity with that of P. spiraeae on S. cantoniensis (AB525940). A pathogenicity test was conducted through inoculation by gently pressing a diseased leaf onto five healthy leaves of a potted Japanese spiraea. Five non-inoculated leaves served as controls. The plants were maintained in a greenhouse at 22°C. Inoculated leaves developed typical symptoms of powdery mildew after 5 days, but the non-inoculated leaves remained symptomless. The fungus presented on the inoculated plant was morphologically identical to that originally observed on diseased plants, fulfilling Koch's postulates. Powdery mildew of S. japonica caused by P. spiraeae has been recorded in Japan, Poland, and Switzerland (2,3). To our knowledge, this is the first report of powdery mildew caused by P. spiraeae on Japanese spiraea in China. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No.11. CBS, Utrecht, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ September 10, 2013. (3) T. Kobayashi. Index of Fungi Inhabiting Woody Plants in Japan. Host, Distribution and Literature. Zenkoku-Noson-Kyoiku Kyokai Publishing Co. Ltd., Tokyo, 2007. (4) S. Matsuda and S. Takamatsu. Mol. Phylogenet. Evol. 27:314, 2003.

First Report of Powdery Mildew Caused by Erysiphe cruciferarum on Chinese Cabbage in China

Chinese cabbage, Brassica rapa ssp. pekinensis (syn. Brassica pekinensis (Lour.) Rupr.), in the Brassicaceae, is an important vegetable grown on about 3 million ha in China. Since 2012, a powdery mildew has been found infecting Chinese cabbage plants (cv. Qingyanchunbai No. 1) after bolting for seed production from autumn through spring 2013 in a greenhouse in Qingdao, China. Symptoms first appeared as circular to irregular white patches on both sides of the leaves, and on stems and pods, often thinly covering the whole surface. A voucher specimen was deposited in the herbarium of Qingdao Agricultural University (Accession No. HMQAU12216). Hyphae were thin-walled, smooth, hyaline, and 4 to 6 μm wide. Appressoria on the mycelia were well developed, lobed, solitary, or in pairs. Conidiophores were erect, cylindrical, 45 to 110 μm long, and comprised 3 to 4 cells. Foot-cells of conidiophores were straight, cylindrical, 16 to 28 μm long, and 7.6 to 10 μm wide. Singly-produced conidia were oblong to cylindrical or somewhat ellipsoid-doliiform, 32 to 56 × 12 to 18 μm, with a length/width ratio of 1.8 to 3.8, with angular/rectangular wrinkling of the outer wall surface, and lacked distinct fibrosin bodies. Germ tubes were produced in the perihilar position of conidia. No chasmothecia were found. These structures are typical of the powdery mildew Pseudoidium anamorph of Erysiphe (2). The specific measurements and characteristics (especially short foot-cells of conidiophores) were consistent with previous records of Erysiphe cruciferarum Opiz ex L. Junell (2,3). To confirm the identification, the complete internal transcribed spacer (ITS) region of rDNA of isolate HMQAU12216 was amplified (4) and sequenced directly. The resulting 649-bp sequence was deposited in GenBank (Accession No. KC878683). A GenBank BLAST search of ITS sequences showed an exact match with those of E. cruciferarum on B. oleracea var. acephala (GU721075) and Oidium sp. on B. pekinensis (AB522714). A pathogenicity test was conducted by gently pressing a symptomatic leaf loaded with conidia onto a leaf of each five, healthy, potted, 40-day-old plants (cv. Qingyanchunbai No. 1). Five non-inoculated plants served as a control treatment. Inoculated plants were isolated from non-inoculated plants in separate rooms in a greenhouse at 20 ± 2°C. Inoculated plants developed signs and symptoms after 10 days, whereas the control plants remained symptomless. The fungus present on the inoculated plants was identical morphologically to that originally observed on diseased plants, thus fulfilling Koch's postulates. Though many Brassica spp. have been known to be infected with E. cruciferarum throughout the world, powdery mildew of Chinese cabbage caused by E. cruciferarum has been reported only in Finland, Germany, and Korea (1,3). To our knowledge, this is the first report of powdery mildew caused by E. cruciferarum on Chinese cabbage in China. Though occurrence of the powdery mildew on Chinese cabbage was noticed in an experimental breeding plot, this finding poses a potential threat to production of this vegetable in China. References: (1) U. Braun. The Powdery Mildews (Erysiphales) of Europe. Gustav Fischer Verlag, Jena, Germany, 1995. (2) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No. 11. CBS, Utrecht, 2012. (3) H. J. Jee et al. Plant Pathol. 57:777, 2008. (4) S. Matsuda and S. Takamatsu. Mol. Phylogen. Evol. 27:314, 2003.