Monte Carlo simulation of a Bonner sphere spectrometer for application to the determination of neutron field in the Experimental Advanced Superconducting Tokamak experimental hall

To assess the neutron energy spectra and the neutron dose for different positions around the Experimental Advanced Superconducting Tokamak (EAST) device, a Bonner Sphere Spectrometer (BSS) was developed at Peking University, with totally nine polyethylene spheres and a SP9 (3)He counter. The response functions of the BSS were calculated by the Monte Carlo codes MCNP and GEANT4 with dedicated models, and good agreement was found between these two codes. A feasibility study was carried out with a simulated neutron energy spectrum around EAST, and the simulated "experimental" result of each sphere was obtained by calculating the response with MCNP, which used the simulated neutron energy spectrum as the input spectrum. With the deconvolution of the "experimental" measurement, the neutron energy spectrum was retrieved and compared with the preset one. Good consistence was found which offers confidence for the application of the BSS system for dose and spectrum measurements around a fusion device.

First Report of Cylindrocarpon destructans var. destructans Causing Black Root Rot of Sanqi (Panax notoginseng) in China

Sanqi (Panax notoginseng (Burk.) F. H. Chen) is planted on >10,000 ha in China and is a popular Chinese medicinal material (2). Black root rot is a recently identified but worsening problem on Sanqi since 2010 in Wenshan, China. Of the plant tubers examined from 185 ha, 8.5 to 27.4% were black with necrotic lesions. The base of leaves of infected plants had brown, sunken, necrotic lesions, and symptomatic plants had one to three chlorotic leaves. A fungus was isolated consistently from the basal leaves, bulb, and tubers of symptomatic plants. Six single-spore isolates were cultured on potato sucrose agar (PSA) at 25 ± 1°C in the dark. The mycelium of each culture was white initially on PSA, and then became rust-colored. The adaxial surfaces of the plates were black. Conidiophores were 13.6 to 167.3 × 1.4 to 21.8 μm (avg. 68.6 × 2.9 μm), single or with up to four levels of branching and two to three branches (or phialides) per level. The basal branches were often divergent, whereas the terminal branches were usually more appressed. Sporodochia were not present. Microconidia were 0-septate, 4.1 to 9.5 × 2.7 to 4.1 μm (avg. 8.2 × 2.9 μm). Conidia were 1- to 3-septate and occasionally 4-septate. One- to 3-septate conidia were clavate, with a truncate or slightly protruding conidial base, 9.2 to 40.8 × 3.5 to 6.8 μm (avg. 26.7 × 5.2 μm); whereas 4-septate conidia were 32.6 to 50.3 × 5.4 to 6.8 μm (avg. 40.9 × 6.5 μm). Chlamydospores were abundant, golden to brown, single or in chains or clumps, and up to 21.8 μm in diameter. PCR amplification was carried out for one isolate, RR926, using rDNA internal transcribed spacer (ITS) primer pairs ITS1F and ITS4 (4). Sequencing of the PCR product (GenBank Accession No. KC904953) revealed 99% similarity (99% coverage) with the ITS sequence of Cylindrocarpon destructans var. destructans (AM419065). Phylogenetic analysis (MEGA 4.1) using the neighbor-joining algorithm placed the isolate in a well-supported cluster (>90% bootstrap value based on 1,000 replicates) with AM419065. Therefore, the pathogen was identified as C. destructans (Zinssm.) Scholten var. destructans (teleomorph Ilyonectria radicicola (Gerlach & L. Nilsson) P. Chaverri & C. Salgado) based on morphological characteristics and rDNA-ITS sequence analysis (1,3). Pathogenicity tests of the six isolates were conducted on five 1-year-old and five 3-year-old plants/isolate. The roots of all plants were washed with sterilized water, and then surface-sterilized with 75% ethanol. Inoculum (1 ml of 10⁶ conidia/ml) of each isolate was brushed onto the roots of each plant with a paintbrush. Inoculated plants were planted in pots in a mixture of sterilized quartz sand:vermiculite:pearlite (2:1:1, v/v). The pots were placed under black shadecloth. The roots of five 1-year-old and five 3-year-old plants were brushed similarly with sterilized water as control treatments. After 30 days, symptoms similar to those on the original diseased plants were observed on the roots of all plants inoculated with the six isolates. The roots of non-inoculated plants remained healthy. The experiment was repeated. The same pathogen was re-isolated from the inoculated plants, but no pathogen was isolated from roots of the control plants. C. destructans var. destructans is widely distributed in soils (1), but to our knowledge, this is the first report of this fungus causing black root rot of Sanqi in China. References: (1) P. Charerri et al. Stud. Mycol. 68:57, 2011. (2) C. Y. Hu. New Rural Technol. 2:59, 2013 (in Chinese). (3) K. A. Seifert and P. E. Axelrood. Can. J. Plant Pathol. 20:115, 1998. (4) K. A. Seifert et al. Phytopathology 93:1533, 2003.

Urethane suppresses renal sympathetic nerve activity in Wistar rats

AIM

To investigate the effects of urethane on renal sympathetic nerve activity (RSNA) in Wistar rats.

MATERIALSAND METHODS

46 rats were randomly allocated in two groups: group A in which rats were injected with urethane; group B in which barbital sodium was used as a control. The changes of RSNA, blood pressure (BP) and heart rate (HR) of each group were evaluated and analyzed.

RESULTS

Compared to the control group, the value of RSNA, BP and HR were all significant decreased in rats of group A after urethane injection (p < 0.05).

CONCLUSIONS

These results suggest that urethane could affect RSNA through somatosensory system.

Comparison of 16S rRNA gene PCR and blood culture for diagnosis of neonatal sepsis

Septicemia is a common cause of morbidity and mortality among newborns in the developing world. However, accurate clinical diagnosis of neonatal sepsis is often difficult because symptoms and signs are often nonspecific. Blood culture has been the gold standard for confirmation of the diagnosis. However, the sensitivity is low and results are usually not promptly obtained. Therefore, the diagnosis of sepsis is often based on clinical signs in association with laboratory tests such as platelets count, immature/total neutrophils ratio (I/T), and a rise in C-reactive protein (CRP). Polymerase chain reaction (PCR) methods for the detection of neonatal sepsis represent new diagnostic tools for the early identification of pathogens.

METHODS

During a 4-month prospective study, 16S rRNA PCR was compared with conventional blood culture for the diagnosis of neonatal bacterial sepsis. In addition, the relationship between known risk factors, clinical signs, laboratory parameters, and the diagnosis of sepsis was considered.

RESULTS

Sepsis was suspected in 706 infants from the intensive neonatal care unit. They all were included in the study. The number of positive cultures and positive PCR results were 95 (13.5%) and 123 (17.4%), respectively. Compared with blood culture, the diagnosis of bacterial sepsis by PCR revealed a 100.0% sensitivity, 95.4% specificity, 77.2% positive predictive value, and 100.0% negative predictive value. In this study, Apgar scores at 5 min, weight, icterus, irritability, feeding difficulties, gestational age (GA), premature rupture of membrane (PRM), platelets count, I/T, and a marked rise in CRP were important in establishing the diagnosis of sepsis in the newborn. In addition, weight, GA, PRM, irritability, duration of antibiotic usage, mortality rate, and number of purulent meningitis cases were significantly different between early-onset sepsis and late-onset sepsis.

CONCLUSION

16S rRNA PCR increased the sensitivity in detecting bacterial DNA in newborns with signs of sepsis, allowed a rapid detection of the pathogens, and led to shorter antibiotic courses. However, uncertainty about the bacterial cause of sepsis was not reduced by this method. 16S rRNA PCR needs to be further developed and improved. Blood culture is currently irreplaceable, since pure isolates are essential for antimicrobial drug susceptibility testing.

Interspecies difference of luteolin and apigenin after oral administration of Chrysanthemum morifolium extract and prediction of human pharmacokinetics

The aims of the present study were to study the interspecies difference in the pharmacokinetics of luteolin and apigenin occurring in Chrysanthemum morifolium extract (CME) among rats, beagle dogs, mini-pigs, and humans, and compared the human pharmacokinetic parameters with the data predicted from the above three animals. The plasma concentrations of luteolin and apigenin were determined with a RP-HPLC method. An interspecies difference of pharmacokinetics was found, especially between rats and other species, the plasma concentration of luteolin was much lower than that of apigenin in rats, although the content of luteolin in CME was higherthan that of apigenin, whereas the plasma concentration of luteolin was much higher than that of apigenin in dogs, mini-pigs and humans. Animal scale-up of some pharmacokinetic parameters of luteolin and apigenin were also performed after rats, beagle dogs, mini-pigs and humans were orally given CME at dosages of 400 mg/kg, 102 mg/kg, 90 mg/kg, and 20 mg/kg, respectively. Linear relationships were obtained between log mean retention time (MRT) and log species body weight (W) (kg), and log elimination half-life (t1/2) (h) and logW. The corresponding allometric equations were MRT=9.382W(0.1711) (R2 = 0.9999) and t1/2 = 4.811W(0.1093) (R2 = 0.9013) for luteolin, MRT = 12.53W(0.0356) (R2 = 0.9980) and t1/2 = 7.940W(0.0294) (R2 = 0.9258) for apigenin, respectively. The predicted human pharmacokinetic parameters (MRT and t1/2) by an allometric approach were 18.6 h and 7.46 h for luteolin, 14.3 h and 8.95 h for apigenin, respectively, which were close to the values obtained from humans (20 mg CME/kg) in the present study. The study has demonstrated the possibility to extrapolate the pharmacokinetic behavior of flavonoids from animals to humans.

[Species-area and species-abundance relationships of arthropod community in various vegetation restoration areas in Zhifanggou watershed, Shaanxi province of Northwest China]

Taking the Zhifanggou watershed in Ansai, Shaanxi Province of Northwest China as a study unit, an investigation on the arthropods in 8 forest stands was conducted from 2006 to 2008, with the species-area and species-abundance relationships of the arthropods in these stands analyzed by various mathematical models. In these forest stands, the species-area relationship of the arthropods accorded with the formula S= CAm With the increase of investigation area, the species number approached to a constant, and the corresponding smallest investigation area was in the order of natural bush > natural forest > Populus davidiana+Robinia pseudoacacia forest > Hippaphae rhamnoides +Caragana mocrophylla forest> Periploca sepium forest > Hippaphae rhamnoides forest > Robinia pseudoacacia forest > Caragana mocrophylla forest, indicating that the more complex the stands, the larger the minimum area needed to be investigated. Based on sampling investigation, the species-abundance models of the arthropods in various stands were established. Lognormal distribution model (LN) was most suitable to fit the arthropod community in natural recovery stands, suggesting that in the arthropod community, there were more species with medial individual amount and fewer abundant species and rare species, and no obvious dominant species. LogCauchy distribution model (LC) was most suitable to fit the arthropod community in mixed and pure stands. As compared with natural recovery stand, mixed and pure stands had more abundant and rare species, and more dominant species.

Proteomic divergence in Arabidopsis autopolyploids and allopolyploids and their progenitors

Autopolyploidy and allopolyploidy are common in many plants and some animals. Rapid changes in genomic composition and gene expression have been observed in both autopolyploids and allopolyploids, but the effects of polyploidy on proteomic divergence are poorly understood. Here, we report quantitative analysis of protein changes in leaves of Arabidopsis autopolyploids and allotetraploids and their progenitors using isobaric tags for relative and absolute quantitation (iTRAQ) coupled with mass spectrometry. In more than 1000 proteins analyzed, the levels of protein divergence were relatively high (~18%) between Arabidopsis thaliana and Arabidopsis arenosa, relatively low (~6.8%) between an A. thaliana diploid and autotetraploid and intermediate (~8.3 and 8.2%) in F(1)- and F(8)-resynthesized allotetraploids relative to mid-parent values, respectively. This pattern of proteomic divergence was consistent with the previously reported gene expression data. In particular, many non-additively accumulated proteins (61-62%) in the F(1) and F(8) allotetraploids were also differentially expressed between the parents. The differentially accumulated proteins in functional categories of abiotic and biotic stresses were overrepresented between an A. thaliana autotetraploid and diploid and between two Arabidopsis species, but not significantly different between allotetraploids and their progenitors. Although the trend of changes is similar, the percentage of differentially accumulated proteins that matched previously reported differentially expressed genes was relatively low. Western blot analysis confirmed several selected proteins with isoforms the cumulative levels of which were differentially expressed. These data suggest high protein divergence between species and rapid changes in post-transcriptional regulation and translational modifications of proteins during polyploidization.

Lung Resistance Protein and Multidrug Resistance Protein in Non-Small Cell Lung Cancer and Their Clinical Significance

This study examined lung resistance protein (LRP) and multidrug resistance protein (MRP) in lung tumour tissue from 92 patients with non-small cell lung cancer (NSCLC) and normal lung tissue from 20 patients with benign lung tumours. The rates for LRP- and MRP-positive tumours among the NSCLC cases were 54% and 59%, respectively, and their combined positive rate was 45%. These rates were significantly higher than in normal lung tissue. The rates of LRP- and MRP-positive tumours were significantly higher among cases of adenocarcinoma than in cases of squamous cell carcinoma, and in highly differentiated tumours compared with tumours of low or moderate differentiation. There was a significant association between LRP- and MRP-positive tumours and a decrease in overall survival. In conclusion, LRP and MRP play a role in multidrug resistance in NSCLC and are related to prognosis in patients with NSCLC.

A novel coaxial tube catheter for central nervous system infusions: performance characteristics in brain phantom gel

We tested a novel neurocatheter in a brain-tissue gel model of drug infusion via convection-enhanced delivery (CED) for the treatment of a variety of neurological diseases. CED is an alternative to systemic administration of agents by intravenous or oral routes, which are often less effective or carry risk of systemic side effects. We investigated two co-axial tube devices, with outer diameters of 1.6 mm and 2.0 mm. Bromophenol blue dye was infused into 400 ml of 0.6% agarose gel at 1 μl/min for 1 h, with/without the inner and outer tubes Luer-locked at the proximal end, with/without the inner tube primed, and with/without the inner tube preloaded into the outer tube upon insertion into the gel. The unlocked, primed, and unloaded configuration produced infusions that resulted in significantly less (p < 0.05) entrapped air escaping into the gel and resulted in no reflux of infusate.

Numb regulates meiotic spindle organisation in mouse oocytes

Numb is an adaptor protein that controls the fate of cells in different species through asymmetrical inheritance by sibling cells during division. It has been investigated extensively in mitosis, mostly in neural progenitor cells, but its function in meiosis remains unknown. The present study was designed to investigate the expression, subcellular localisation and functional roles of Numb during mouse oocyte meiotic maturation. Using real-time polymerase chain reaction and western blotting, we found that the expression of Numb increased from the germinal vesicle (GV) to MII stages. Immunofluorescent staining revealed that Numb was mainly concentrated in the GV before meiosis resumption, aggregated in the vicinity of the chromosomes after GV breakdown and then localised to the spindle poles from prometaphase I to MII. Nocodazole treatment resulted in spindle destruction and Numb diffusion into the cytoplasm. However, Numb appeared at the spindle poles again once the spindles had formed when nocodazole-treated oocytes were washed and cultured for spindle recovery. Depletion of Numb by RNA interference resulted in chromosome misalignment, spindle deformation and even doubled spindle formation. Our results suggest that Numb is critical for spindle organisation during mouse oocytes meiosis. The present study provides evidence of a new function for Numb in addition to its action as a cell fate-determining factor.

Microvessel density and expression of thrombospondin-1 in non-small cell lung cancer and their correlation with clinicopathological features

Microvessel density and thrombospondin-1 (TSP-1) expression were analysed in 42 non-small cell lung cancer (NSCLC) specimens and 40 normal lung tissue specimens using immunohistochemistry. Microvessel density was significantly higher and TSP-1 expression significantly lower in NSCLC tissue compared with normal tissue. Significantly lower levels of TSP-1 expression and higher microvessel densities were found in late-stage NSCLC compared with early-stage NSCLC, and in those with lymph node metastasis compared with those without metastasis. A statistically significant inverse correlation was observed between TSP-1 expression and microvessel density in squamous cell carcinoma but not in adenocarcinoma. These results suggest a close relationship between microvessel density and NSCLC tumour progress, and that a high expression of TSP-1 may play an important role in inhibiting tumour occurrence and development. The lack of correlation between microvessel density and TSP-1 expression in adenocarcinoma suggests that the mechanism of tumour inhibition by TSP-1 varies according to histological type.

Changes and effects of plasma arginine vasopressin in traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) is a common disease accompanied by chronic morbidity and mortality. The pathological mechanism and effective pharmacological treatments of TBI remain undetermined. It is suggested that AVP is involved in TBI. It is thus interesting to investigate the changes and effects of plasma AVP in clinical trials.

METHODS

The serum concentrations of AVP, serum electrolytes, and serum osmolarity in a total of 23 TBI patients were dynamically monitored (on admission, Day 1, Day 3, and Day 5). Relationship between AVP and severity of brain injury and functional outcome were evaluated, respectively.

RESULTS

The mean AVP serum concentrations in the TBI group were significantly higher than those recorded in the control (CTRL) group on intensive care unit (ICU) admission and Day 1 (p<0.05). On Day 3 and Day 5, the differences between those groups were not significant (p>0.05). The negative correlations were found between sodium and AVP (r=-0.35; p<0.05) and between osmolarity and AVP (r=-0.42; p<0.05). In poor outcome group, the mean AVP serum concentrations were significantly higher than in good outcome group and CTRL group (p<0.05). A statistically significant correlation was also found between AVP on ICU admission and the initial Glasgow Coma Scale (r=0.47; p<0.05).

CONCLUSION

We suggest that AVP is involved in the pathophysiology process of secondary brain damage after TBI. It seems that AVP antagonist is a promising target for the treatment of TBI, while further studies should be carried out.

Superconducting properties of the Fe-based layered superconductor LaFeAsO0.9F0.1-delta

We have employed a new route to synthesize single phase F-doped LaOFeAs compound and confirmed the superconductivity above 20 K in this Fe-based system. We show that the new superconductor has a rather high upper critical field of over 50 T. A clear signature of superconducting gap opening below T(c) was observed in the far-infrared reflectance spectra, with 2Delta/kT(c) approximately 3.5-4.2. Furthermore, we show that the new superconductor has electron-type conducting carriers with a rather low-carrier density.

Low-temperature electronic transport in single K(0.27)MnO(2)·0.5H(2)O nanowires: enhanced electron-electron interaction

The current-voltage (I-V) characteristics and electrical resistivity of isolated potassium manganese oxide (K(0.27)MnO(2)·0.5H(2)O) nanowires prepared by a simple hydrothermal method were investigated over a wide temperature range from 300 to 4 K. With lowering temperature, a transition from linear to nonlinear I-V curves was observed around 50 K, and a clear zero bias anomaly (i.e., Coulomb gap-like structure) appeared on the differential conductance (dI/dV) curves, possibly due to enhanced electron-electron interaction at low temperatures. The temperature dependence of resistivity, [Formula: see text], follows the Efros-Shklovskii (ES) law, as expected in the presence of a Coulomb gap. Here we note that both the ES law and Coulomb blockade can in principle lead to a reduced zero bias conductance at low temperatures; in this study we cannot exclude the possibility of Coulomb-blockade transport in the measured nanowires, especially in the low-temperature range. It is still an open question how to pin down the origin of the observed reduction to a Coulomb gap (ES law) or Coulomb blockade.

Ubiquitin-mediated activation of TAK1 and IKK

Transforming growth factor beta activated kinase-1 (TAK1), a member of the mitogen-activated protein kinase kinase kinase family, has emerged as a key regulator of signal transduction cascades leading to the activation of the transcription factors nuclear factor-kappa B (NF-kappaB) and activator protein-1 (AP-1). Stimulation of cells with cytokines and microbial pathogens results in the activation of TAK1, which subsequently activates the I-kappa B kinase complex (IKK) and mitogen-activated protein (MAP) kinases, culminating in the activation of NF-kappaB and AP-1, respectively. Recent studies have shown that polyubiquitination of signalling proteins through lysine (Lys)-63-linked polyubiquitin chains plays an important role in the activation of TAK1 and IKK. Unlike Lys-48-linked polyubiquitination, which normally targets proteins for degradation by the proteasome, Lys-63-linked polyubiquitin chains act as scaffolds to assemble protein kinase complexes and mediate their activation through proteasome-independent mechanisms. The concept of ubiquitin-mediated activation of protein kinases is supported by the discoveries of ubiquitination and deubiquitination enzymes as well as ubiquitin-binding proteins that function upstream of TAK1 and IKK. Recent biochemical and genetic studies provide further insights into the mechanism and function of ubiquitin signalling and these advances will be the focus of this review.

Molecular marker genotypes, heterozygosity and genetic interactions explain heterosis in Arabidopsis thaliana

The underlying mechanisms for hybrid vigor or heterosis are elusive. Here we report a population of recombinant inbred lines (RILs), derived from the two ecotypes, Col and Ler, which can serve as a permanent resource for studying the molecular basis of hybrid vigor in Arabidopsis. Using a North Carolina mating design III (NCIII), we determined the additive and dominant nature of gene action in this population. We detected heterosis among crosses of RILs with one of the two parents (Col and Ler) and analyzed genotypes and heterozygosities for RILs and test cross families (RILs crossed to Col and Ler) using a total of 446 published molecular markers. The performance of RILs and additive and dominant components in the test cross families were used to analyze QTLs for 16 traits, using QTL cartographer and composite interval mapping with 1,000 permutations for each trait. Our data suggest that locus-specific and/or genome-wide differential heterozygosity, including epistasis, plays an important role in the generation of the observed heterosis. Furthermore, the hybrid vigor occurred between two closely related ecotypes, and provides a general mechanism for novel variation generated between genetically similar materials.

Effects of sucrose concentration on the developmental potential of human frozen–thawed oocytes at different stages of maturity

BACKGROUND

Success of human oocyte cryopreservation depends on multiple cryobiological factors that could influence the developmental potential of the oocytes. The objective of this study was to examine the effects of different sucrose concentrations on the developmental potential of human frozen-thawed oocytes at different maturity stages.

METHODS

A total of 355 oocytes collected from small follicles were randomly divided into three groups and two groups (B and C) were cryopreserved using slow-freezing method. Group A included 131 oocytes at different maturity stages without freezing. Another 119 oocytes in Group B were cryopreserved with 0.1 M sucrose and 105 oocytes in Group C with 0.2 M sucrose concentration.

RESULTS

The post-thaw survival rate of the oocytes and the cleavage rate in Group C were significantly higher than that of Group B (P<0.05). For immature metaphase I (MI) stage oocytes, a significant difference was found in the maturation rate between Group C and Group B (P<0.05). The maturation rate for the GV oocytes in Groups A and C was significantly higher than Group B (P<0.01).

CONCLUSIONS

The results suggested that sucrose concentration of 0.2 M in the cryoprotectant solution is more suitable for human oocyte cryopreservation.