Boron carbide composites with highly aligned graphene nanoplatelets: light-weight and efficient electromagnetic interference shielding materials at high temperatures.

B4C-based ceramic composites containing 0-2 vol% highly aligned graphene nanoplatelets (GNPs) are fabricated. The electromagnetic interference (EMI) shielding properties of the obtained composites are investigated at X-band (8.2-12.4 GHz) frequency range from room-temperature up to 800 °C. All composites exhibit outstanding EMI shielding properties with satisfactory frequency- and thermal-stability. The shielding effectiveness (SE) of GNP/B4C composites increases monotonically with increasing GNP loading. Superior room-temperature SE close to 40 dB is achieved with only 2 vol% GNPs and high SE around 35 dB still persists at 800 °C. Considering their relatively low density, GNP/B4C composites possess a high specific shielding effectiveness (SSE) of 16 dB cm3 g-1 which is among the highest values in reported ceramic-based shielding composites. Especially, the GNP/B4C composite with 2 vol% GNPs exhibits the highest SSE/t (SSE divided by thickness) values at temperatures above 200 °C for all reported shielding composites, indicating that GNP/B4C composites belong to the most promising high-temperature shielding composites. The excellent shielding properties of GNP/B4C composites arise mainly from the high electrical conductivity, high dielectric loss and the multiple reflections by the highly aligned and large-sized GNP layers.

Whole-exome sequencing identifies a homozygous donor splice-site mutation in STAG3 that causes primary ovarian insufficiency.

Primary ovarian insufficiency (POI) is the depletion or loss of normal ovarian function, which cause infertility in women before the age of 40 years. Two homozygous germline truncation mutations in STAG3 gene had been reported to causes POI in consanguineous families. Here, we aimed to identify the genetic cause of POI in 2 affected sisters manifested with primary amenorrhea and partial development of secondary sexual characters with normal range of height of a consanguineous Han Chinese family. Whole-exome and Sanger sequencing identified a homozygous donor splice-site mutation (NM_012447.2: c.1573+5G>A) in the STAG3 gene. RT-PCR revealed that the mutation causes loss of wild-type donor splice-site which leads to aberrant splicing of STAG3 mRNA and consecutive formation of STAG3 alternative transcript (p.Leu490Thrfs*10) . This is the first report of splice-site mutation of STAG3 gene causes POI in 2 Han Chinese patients.

Effect of temperature on endogenous hormone levels and opposite phyllotaxy in maize leaf primordial.

Newly identified maize (Zea mays) mutants with opposite leaf phyllotaxy are important in the study of the maize crop. Previous studies have revealed the developmental mechanism of opposite phyllotaxy on the physiological, cellular, and molecular levels. However, there have been few reports regarding the effects of changes in endogenous hormone levels in maize leaf primordia under different conditions. We conducted field studies to examine the influence of different environmental factors on leaf primordia differentiation. Our results indicated that compared with other major environmental factors, temperature was significantly positively correlated with the ratio of maize plants with opposite phyllotaxy. We examined endogenous hormone levels in maize at different temperatures using an enzyme-linked immunosorbent assay. The results showed that the ratio of maize plants with opposite phyllotaxy was mainly influenced by the cytokinin/auxin ratio. In addition, at the same temperature, the ratio of cytokinin/auxin in maize with opposite phyllotaxy was significantly higher than that near isogenic lines with alternate phyllotaxy.

Effects of dietary supplementation with the combination of zeolite and attapulgite on growth performance, nutrient digestibility, secretion of digestive enzymes and intestinal health in broiler chickens.

This study was designed to investigate the effects of basal diets supplemented with a clay product consisting of zeolite and attapulgite (ZA) at 1:1 ratio on growth performance, digestibility of feed nutrients, activities of digestive enzymes in small intestine and intestinal health in broiler chickens. In experiment 1, 112 one-day-old male chickens were randomly divided into 2 groups with 8 replicates of 7 chickens each. In experiment 2, 84 one-day-old male chickens were randomly allocated into 2 groups consisting 6 replicates of 7 chickens each. The experimental diets both consisted of a maize-soybean basal control diet supplemented with 0% or 2% ZA. The diets were fed from 1 to 42 days of age. The results showed that ZA supplementation could increase body weight gain (BWG) and feed intake (FI), but had no significant effect on feed conversion ratio. The apparent digestibility values of crude protein and gross energy were significantly increased (p<0.05) by ZA from 14 to 16 d and 35 to 37 d. Dietary ZA treatment significantly increased (p<0.05) the activities of amylase, lipase and trypsin in jejunal digesta and the activities of maltase and sucrase in jejunal mucosa on days 21 and 42. The ZA supplementation also significantly increased (p<0.05) the catalase activity, reduced (p<0.05) the malondialdehyde concentration in the jejunal mucosa. In addition, a decrease of serum diamine oxidase activity and an increase (p<0.05) in concentration of secretory immunoglobulin A in jejunal mucosa were observed in birds treated with ZA on 21 and 42 days. It is concluded that ZA supplementation (2%) could partially improve the growth performance by increasing BWG and FI. This improvement was achieved through increasing the secretion of digestive enzymes, enhancing the digestibilites of nutrients, promoting intestinal health of broiler chickens.

Effects of surfactants on the photolysis of chlorothalonil on pepper (Capsicum annuum var. grossum Sendt).

Chlorothalonil is a widely used fungicide on pepper and other vegetables in China. The present study was aimed to evaluate effects of three different surfactants, sodium dodecyl sulfonate (SDS), Span-20, and cetyltrimethylammonium bromide (CTAB), on the photolysis of chlorothalonil on peppers under irradiation of either high-pressure mercury lamp (HPML) or sunlight inside and outside greenhouse. Results showed that both SDS and Span-20 at a low concentration exhibited a photosensitization effect on the photolysis of chlorothalonil under HPML. Such effect gradually decreased with increasing concentrations of either surfactant prior to photoquenching effects observed. In contrast, CTAB showed a photoquenching effect on chlorothalonil photolysis, which was gradually enhanced with an increasing CTAB concentration. SDS, Span-20, and CTAB had consistent effects on the photolysis of chlorothalonil under sunlight as those observed under HPML irradiation. The use of appropriate surfactants as pesticide additives at optimal concentrations could decrease the residue of pesticide in agricultural food and improve food safety.

Using SNP array to identify aneuploidy and segmental imbalance in translocation carriers.

Translocation is one of the more common structural rearrangements of chromosomes, with a prevalence of 0.2%. The two most common types of chromosomal translocations, Robertsonian and reciprocal, usually result in no obvious phenotypic abnormalities when balanced. However, these are still associated with reproductive risks, such as infertility, spontaneous abortion and the delivery of babies with mental retardation or developmental delay. In recent years, array-based whole-genome amplification (WGA) technologies, including microarray comparative genomic hybridization (array CGH; aCGH) and single-nucleotide polymorphism (SNP) micro-arrays, have enabled the screening of every chromosome for whole-chromosome aneuploidy and segmental imbalance. These techniques have been shown to have clinical application for translocation carriers. Promising studies have indicated that array-based PGD of translocation carriers can lead to transfer pregnancy rates of 45-70% [2]. In addition to genetic testing techniques, the embryo biopsy stage (polar body, cleavage embryo or blastocyst) and the mode of embryo transfer (fresh or frozen embryos) can affect the outcome of PGD. It is now generally recommended that blastomere biopsy should be replaced by blastocyst biopsy to avoid a high mosaic rate and biopsy-related damage to cleavage-stage embryos, which might affect embryo development. However, more clinical data are required to confirm that the technique of SNP array-based PGD (SNP-PGD) combined with trophectoderm (TE) biopsy and frozen embryo transfer (FET) is superior to traditional FISH-PGD combined with Day 3 (D3) blastomere biopsy and fresh embryo transfer.

Single-nucleotide polymorphism microarray-based preimplantation genetic diagnosis is likely to improve the clinical outcome for translocation carriers.

STUDY QUESTION: Is preimplantation genetic diagnosis (PGD) for translocation carriers more effective when done with a single-nucleotide polymorphism (SNP) array using trophectoderm (TE) biopsy and frozen embryo transfer (FET) compared with traditional PGD based on fluorescence in situ hybridization (FISH-PGD) using blastomere biopsy and fresh embryo transfer? SUMMARY ANSWER: The procedure using the SNP array combined with TE biopsy and FET significantly improves the clinical pregnancy rate for translocation carriers. The miscarriage rate also slightly decreases. WHAT IS KNOWN ALREADY: FISH-PGD has been widely used in translocation carriers but the clinical outcomes have not been ideal. SNP arrays can detect both chromosome segmental imbalances and aneuploidy, and may overcome the limitations of FISH in PGD for translocation carriers. STUDY DESIGN, SIZE AND DURATION: This was a retrospective study of 575 couples with chromosomal translocations, including 169 couples treated by SNP-PGD between October 2011 and August 2012, and 406 couples treated by FISH-PGD between January 2005 and October 2011. PARTICIPANTS/MATERIALS, SETTING, METHODS: The study was set in an IVF center at the Reproductive and Genetic Hospital of CITIC-Xiangya, China. In total, 169 couples underwent SNP analysis, including 52 Robertsonian translocation carriers and 117 carriers of reciprocal translocations. Blastocysts (n = 773) were biopsied and FET was carried out on the balanced embryos. Four hundred and six couples underwent FISH-PGD, including 149 Robertsonian translocation carriers and 257 reciprocal translocation carriers. In total, 3968 embryos were biopsied and balanced embryos were transferred fresh. The SNP-PGD results and clinical outcomes were compared with those of FISH-PGD. MAIN RESULTS AND THE ROLE OF CHANCE: Reliable SNP-PGD results were obtained for 717 out of 773 (92.8%) biopsied blastocysts. The proportions of normal/balanced embryos, embryos with translocation-related and translocation-unrelated abnormalities, the median number of embryos per patient, the ongoing pregnancy rate per embryo transfer and the miscarriage rate were 58, 23, 19, 2, 69 and 12%, respectively, for Robertsonian translocation carriers and 36, 52, 12, 1, 74 and 11%, respectively, in reciprocal translocation carriers. Reliable FISH-PGD results were obtained for 3452 out of 3968 (87.0%) biopsied embryos. The proportions of normal/balanced embryos, unbalanced embryos, the median number of embryos per patient, the ongoing pregnancy rate per transfer and the miscarriage were 36, 64, 3, 38 and 17%, respectively, for Robertsonian translocation carriers and 20, 80, 1, 39 and 16%, respectively, for reciprocal translocation carriers. Thus, SNP-PGD achieved a higher pregnancy rate but a lower miscarriage rate than FISH-PGD. There were no significant differences in maternal age, basal endocrine level and the average number of retrieved oocytes and good-quality D3 embryos in the SNP-PGD group compared with the FISH-PGD group. LIMITATIONS, REASONS FOR CAUTION: This was a retrospective study with the two groups treated in different periods; therefore, there is a chance of sample bias and a possibility that the results were influenced by other factors that changed over time. Furthermore, the two treatment protocols differ in several respects and we cannot say which makes the greatest contribution to the difference in success. Complete pregnancy outcomes of SNP-PGD have not been obtained as some embryos have not been transferred yet. We cannot exclude differences between the final data and the data in the present manuscript. WIDER IMPLICATIONS OF THE FINDINGS: The adoption of SNP-PGD combined with TE biopsy and FET may significantly improve the clinical pregnancy rate, and decrease the miscarriage rate after PGD for translocation carriers.

Climatic factors correlate with innate immune response in children with Dermatophagoides farinae-induced allergic asthma.

OBJECTIVE: To determine the effect of climatic factors on immune markers in children with Dermatophagoides farinae induced asthma. METHODS: Serum concentrations of macrophage migration inhibitory factor (MIF), eosinophil cationic protein (ECP) and D. farinae-specific immunoglobulin E (DF-sIgE), together with peripheral blood eosinophil counts, were measured in children with D. farinae induced (n = 75) or non-D. farinae-induced asthma (n = 17), and in healthy controls (n = 30). Mean temperature and relative humidity in the month before enrolment were calculated from meteorological data. RESULTS: MIF, ECP and eosinophil counts were significantly higher in children with D. farinae-induced asthma than in controls, but comparable with non-D. farinae-induced asthma. Children with D. farinae-induced asthma in a low temperature (< 16 °C) or low relative humidity (< 70%) climate had significantly lower DF-sIgE, MIF, ECP and eosinophil counts than those in a high temperature or high humidity climate. DF-sIgE correlated positively with MIF, ECP and eosinophil count in D. farinae-induced asthma. CONCLUSIONS: Temperature and humidity influenced MIF, ECP, eosinophil count and DF-sIgE in D. farinae-induced asthma. Understanding this relationship may provide new strategies for asthma prevention and treatment.

Molecular mapping of genes for opposite leafing in maize using simple-sequence repeat markers.

Maize with opposite phyllotaxy (OP) and also initiating ears in opposite pairs is an aberrant mutant and also precious material for maize breeding and plant evolution studies. Mapping and identifying the markers closely linked to genes for the OP trait are essential for cloning the gene and marker-assisted selection in breeding. We established H14D, a near-isogenic line of the OP trait with H53 genetic background. We found that the OP trait is regulated by two independent dominant genes with mutually complementary relations, named Opp-1 and Opp-2. Screening of seven simple-sequence repeat (SSR) markers among the 105 pairs of SSR primers showed polymorphism between the inbred lines H14D and H53. The polymorphic SSR markers were then used to determine linkage with the trait in an F(2) population with 441 progeny, suggesting that SSR marker umc2094 in the Bin2.01 region is linked with Opp-1 at 6.7 cM, and bnlg1831 in Bin2.06 is linked with Opp-2 at 6.1 cM. Further investigation showed that bnlg1092 and umc1028 are linked to Opp-1 and Opp-2 genes, with genetic distances of 12.2 and 1.9 cM. It was also found that the four SSR markers flank the two OP genes, respectively. These results will be useful for marker-assisted selection breeding of OP maize and will also strengthen the basis for cloning of the opposite leafing gene.

Differences between karyotypically normal and abnormal human embryonic stem cells.

OBJECTIVES: To compare different biological characteristics of human embryonic stem cells (HESCs) between those with normal and those with abnormal karyotype. MATERIALS AND METHODS: Culture-adapted HESCs (chHES-3) with abnormal karyotype were compared with karyotypically normal cells, with regard to pluripotency and differentiation capacity, ultrastructure, growth characteristics, gene expression profiles and signalling pathways. RESULTS: We found a new abnormal karyotype of HESCs. We observed that chHES-3 cells with normal and abnormal karyotypes shared similarities in expression markers of pluripotency; however, karyotypically abnormal chHES-3 cells had a tendency for differentiation towards ectoderm lineages and were easily maintained in suboptimal culturing conditions. Abnormal chHES-3 cells displayed relatively mature cell organelles compared to normal cells, and karyotypically abnormal chHES-3 cells had increased survival and population growth. Genes related to cell proliferation and apoptosis were up-regulated, but genes associated with genetic instability (p53, Rb, BRCA1) were down-regulated in the karyotypically abnormal cells. CONCLUSION: Karyotypically abnormal chHES-3 cells had a more developed capacity for proliferation, resistance to apoptosis and less genetic stability compared to normal chHES-3 cells and may be an excellent model for studying and characterizing initial stages that determine transition of embryonic stem cells into cancer stem cells.

Activation of a protease cascade involved in patterning the Drosophila embryo.

Dorsoventral patterning of the Drosophila embryo is initiated by a ventralizing signal. Production of this signal requires the serine proteases Gastrulation Defective (GD), Snake, and Easter, which genetic studies suggest act sequentially in a cascade that is activated locally in response to a ventral cue provided by the pipe gene. Here, we demonstrate biochemically that GD activates Snake, which in turn activates Easter. We also provide evidence that GD zymogen cleavage is important for triggering this cascade but is not spatially localized by pipe. Our results suggest that a broadly, rather than locally, activated protease cascade produces the ventralizing signal, so a distinct downstream step in this cascade must be spatially regulated to restrict signaling to the ventral side of the embryo.

[Effect of BSAP/Pax-5 on the development, proliferation and differentiation of B lymphocyte cell].

BSAP, a B cell lineage-specific activator protein, is a nucleus transcription factor and is encoded by the Pax-5 gene. It is a critical modulator of B cell development, proliferation and differentiation. BSAP also influences B cell immunoglobulin secretion at later stages of B cell differentiation.

Gastrulation defective is a serine protease involved in activating the receptor toll to polarize the Drosophila embryo.

The dorsoventral axis of the Drosophila embryo is induced by a ventrally restricted ligand for the receptor Toll. The Toll ligand is generated by a proteolytic processing reaction, which occurs at the end of a proteolytic cascade and requires the gastrulation defective (gd), nudel, pipe, and windbeutel genes. Here we demonstrate that the GD protein is a serine protease and that the three other genes act to restrict GD activity to the ventral side of the embryo. Our data support a model in which the GD protease catalyzes the ventral activation of the proteolytic cascade that produces the Toll ligand.

[Effect and mechanism of active fraction A guizhi decoction on dual-directional thermoregulation: effect on heat shock protein in hypothalamus of rats].

OBJECTIVE: To investigate the effect of active fraction A in Guizhi Decoction (Fr.A) on dual-directional thermoregulation and its mechanism of influencing heat shock protein (HSP) in hypothalamus. METHOD: Using Western blot method to measure HSP of hypothalamus in febrile and hypothermal rats. RESULTS: Regulating the body temperature in dual-direction, Fr.A could antagonize the decrease of HSP contents of hypothalamus in hypothermal rats induced by aminopyrine, and abate the HSP content in febrile rats induced by yeast. CONCLUSION: Fr.A adjusts the body temperature through regulating the contents of HSP of hypothalamus in febrile and hypothermal rats.