In their natural habitat, bacteria are consumed by bacterivorous nematodes; however, they are not simply passive preys. Here we report a defensive mechanism used by certain bacteria to mobilize ...nematode-trapping fungi to kill nematodes. These bacteria release urea, which triggers a lifestyle switch in the fungus Arthrobotrys oligospora from saprophytic to nematode-predatory form; this predacious form is characterized by formation of specialized cellular structures or 'traps'. The bacteria significantly promote the elimination of nematodes by A. oligospora. Disruption of genes involved in urea transport and metabolism in A. oligospora abolishes the urea-induced trap formation. Furthermore, the urea metabolite ammonia functions as a signal molecule in the fungus to initiate the lifestyle switch to form trap structures. Our findings highlight the importance of multiple predator-prey interactions in prey defense mechanisms.
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•Describe the use of a Nu Plasma 1700 MC-ICP-MS in high-resolution mode to determine Fe isotopic ratios at the center of Fe peaks instead of shoulders.•The measured iron isotopic ...compositions of geological reference materials agreed with the published data within 2 sd analytical uncertainties.•The precision and long-term reproducibility analyses are better than ±0.03‰ for δ56Fe (2 sd) measured by MC-ICP-MS with Ni doping and SSB method.
Herein, we describe the use of a Nu Plasma 1700 multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS) in true high-resolution mode to determine Fe isotopic ratios at the center of Fe peaks instead of their shoulders. A standard-sample bracketing (SSB) technique and a Ni doping method were used for instrumental mass bias calibration. The effects of Fe/Ni ratio and plasma mode were investigated in order to establish a high-precision Fe isotope analysis method. The results showed that the Ni-doping method provided more precision isotopic ratios than that of the SSB technique. Moreover, this work also presents Fe isotopic compositions of some geological reference materials (BCR-2, BHVO-2, AGV-2, GSR-1, GSR-2, GSR-3, GSP-2, and DSN-1), which were highly accurate with respect to the international Fe isotope standard IRMM-014. The iron isotopic compositions of most geological reference materials measured in this study agreed with the previously published data within quoted analytical uncertainties. Long-term reproducibility analyses of all samples indicate that the obtained isotopic ratios are highly reproducible, with precisions of better than ±0.03‰ for δ56Fe (2 sd) and ±0.06‰ (2 sd) for δ57Fe. Our results demonstrated the usefulness of internal element doping for improving the stability and precision of isotope analysis by MC-ICP-MS.
Status of the cutting tool has a great impact on the quality of the final product during the machining processes. However, the cutting tool condition monitoring (TCM) system mostly stays at the stage ...of research and development in the literature. In this research task, a combination of multiple sensors including three-axis accelerometer and acoustic emission (AE) sensor and driver current detector of the spindle, is used to collect respective data of the milling cutter during machining process of the CNC machines. The information is used indirectly to justify the tool wear level. During the machining process, two types of the cutter with different materials are considered with cutting paths classified into three categories: straight cutting path, square cutting path, and circle cutting path. We also propose a signal feature extraction method combined with an ANN for the TCM system. It can be used to perceive the difference between tool materials and wear level in three standard types of cutting path. Finally, online analysis supported by the TCM system is developed to show the identification accuracy of tool wear.
Magnesium alloys have many distinguished advantages; therefore, they are more and more popularly used in lightweight design of automotive and aviation manufacturing industries. However, its poor ...plasticity at room temperature has prevented its further application, especially in magnesium alloy sheet forming process. To expand the application of magnesium alloy sheets, single-point incremental forming process for rapid prototype manufacturing and small-scale productions of sheet metal was investigated. By combining finite element numerical simulations with physical experiments, the relationships between the maximum thickness differences and different process parameters are explored, and the optimal process parameters for forming a certain straight wall cylindrical part of AZ31 magnesium alloy were determined. Based on the analysis of the results, the formability of AZ31 magnesium alloy sheet using warm single-point incremental forming (SPIF) is improved with the increases of number of forming stage, forming temperature, and tool diameter but reduced with the increase of feed rate and interlayer spacing. The suitable forming temperature for AZ31 magnesium alloy sheet is about 250°C. For forming the deeper straight wall cylindrical parts, at least four forming stages are needed.
The aim of this study was to investigate the genetic polymorphism of 20 short tandem repeat (STR) loci including D1S1656, D2S1338, D3S1358, D5S818, D6S1043, D7S820, D8S1179, D12S391, D13S317, ...D16S539, D18S51, D19S433, D21S11, CSF1PO, FGA, Penta D, Penta E, TH01, TPOX, and vWA in Han population of Henan, China and to assess its value in forensic science. Genomic DNA was extracted from 274 blood samples of unrelated healthy individuals in the Henan Han population. Alleles were amplified with PowerPlex® 21 system kit and PCR products were detected with ABI3130 genetic analyzer (Applied Biosystems) and the data were analyzed with modified PowerStats v1.2. A total of 229 alleles were observed in this Han population and the allelic frequencies ranged from 0.0020 to 0.5090 in the present study. Observed genotype distributions for each locus do not show deviations from Hardy–Weinberg equilibrium expectations (p < 0.05). The combined power of discrimination, combined power of exclusion, and combined matching probability of this 20 STR loci were 0.999999999, 0.999999994603, and 4.0433 × 10−24, respectively. The 20 STR loci are highly polymorphic in the Han population of Henan, China and they may be of great value in forensic science and human population genetics.
To develop and validate a prediction score for a successful retrograde procedure in chronic total occlusion (CTO) percutaneous coronary intervention (PCI).
A total of 228 CTO lesions in 223 patients ...who underwent PCI by retrograde approach were analyzed. All subjects were randomly grouped to a derivation set and a validation set at a ratio of 2:1. A successful retrograde procedure was set as the end point. Each of the identified predictors for the end point by logistic regression was assigned 1 point and summed.
Independent predictors of a successful retrograde procedure were Werner's score odds ratio (OR) 4.841, 95% confidence interval (CI) 1.952-12.005, p = 0.001, diameter of distal CTO segment (OR 5.263, 95% CI 2.067-13.398, p < 0.001) and tortuous collateral (type b; OR 0.119, 95% CI 0.032-0.444, p = 0.002). The predictive model developed in the derivation set stratified the difficulty of achieving a successful retrograde procedure into 4 grades - very difficult (10.5%), difficult (23.7%), intermediate (50.7%) and easy (15.1%) - and was demonstrated significantly in the validation set: very difficult (15.8%), difficult (18.4%), intermediate (47.4%) and easy (18.4%). The area under the receiver-operating characteristic curve was 0.832 ± 0.042 for the derivation set and 0.912 ± 0.041 for the validation set with an almost equal performance.
According to the experience of our center, this model performed excellently in predicting the difficulty in achieving a successful retrograde procedure.
Male infertility has evolved from a common reproductive system disease to a major social issue. Youjing granule (YG) is a Chinese medicinal material used as a therapy method for tonifying the kidneys ...and removing dampness due to its pathogenic characteristics. YG has been shown to regulate sperm quality in clinical trials, but the underlying mechanism is not fully understood. The present study was aimed to explore the protective effects and mechanism of action of YG on male reproductive system damage caused by methyl methane sulfonate (MMS). We first established an infertility model of rats through oral administration of MMS and then treated with YG. To determine the effect of YG, spermatogenesis, microvascular density, and secretory function of Leydig cells and Sertoli cells in rats were assessed. Spermatogonial stem cells (SSCs) were co-cultured with mouse embryo fibroblast (MEF) cells as an in vitro cell model before exposure to serum containing YG. Furthermore, the proliferation and apoptosis of SSCs were measured. Results indicated that YG increased the expression of self-renewal and proliferation-related molecules such as glial cell line derived neurotrophic factor (GDNF) and fibroblast growth factor-2 (FGF2), and improved the quality of sperm and the proliferation of SSCs. In conclusion, YG may protect spermatogenetic function of rats through regulating the proliferation and self-renewal of SSCs.
Immunotherapy has developed rapidly and has gradually become one of the important methods for treatment of gastric cancer (GC). The research on tumor infiltrating immune cells (TIICs) and ...immune-related genes in the tumor microenvironment (TME) greatly encourages the development of immunotherapy. The devolution algorithm (CIBERSORT) was applied to infer the proportion of 22 TIICs based on gene expression profiles of GC tissues, which were downloaded from TCGA and GEO. TCGA was utilized to analyze the differential expression of immune-related genes, and explore the potential molecular functions of these genes. We have observed the enrichment of multiple TIICs in microenvironment of GC. Some of these cells were closely related to tumor mutational burden (TMB), microsatellite instability (MSI), Fuhrman grade, and TNM staging. Survival analysis showed that the infiltration level of CD8
T cells, activated CD4
memory T cells and M2 macrophages were significantly related to the prognosis of GC patients. The functional enrichment analysis of immune-related genes revealed that these genes were mainly associated with cytokine activation and response. Four significant modules were screened by PPI network and 20 key genes were screened from the modules. The expression levels of CALCR and PTH1R are strikingly related to the expression of immune checkpoint and the prognosis of GC patients. The type and number of TIICs in microenvironment of GC, as well as immune-related genes are closely related to tumor progression, and can be used as important indicators for patient prognosis assessment.
We report the observation of local superconductivity induced at the point contact formed between a normal metal tip and tungsten carbide-a triple point topological semimetal with superhardness. ...Remarkably, the maximum critical temperature is up to near 12 K but insensitive to the tip's magnetism. The lateral dimensions of the superconducting puddles were evaluated and the temperature dependencies of the superconducting gap and upper critical field were also obtained. These results put constraints on the explanation of the induced superconductivity and pave a pathway for exploring topological superconductivity.
To evaluate cadmium (Cd) remediation capacity of gray poplar (
Populus
×
canescens
Sm. referred to the hybrid of
Populus tremula
L. ×
Populus alba
L.), the glasshouse experiment was conducted in ...hydroponics, and the effects of Cd (0, 10, 30, 50, and 70 μM) on plant growth as well as Cd uptake and translocation were investigated. The growth rate of all tissues in
P.
×
canescens
decreased slowly with an increase in Cd concentrations. Among different tissues, the root exhibited the highest level of bio-concentration factor (BCF), followed by leaves, bark, and wood. BCFs in bark and wood significantly decreased with an increase in Cd concentrations. The translocation factor in different tissues firstly increased and then declined with an increase in Cd concentrations, respectively. The translocation factor in different tissues decreased slowly with an increase in Cd concentrations. Cd accumulation rates significantly increased and reached about sevenfold the level after 70 μM than that observed after 0 μM (control) for 28 days. These results indicated that
P.
×
canescens
have good tolerance against Cd stress, varying in Cd accumulation and translocation. These properties need to be taken into account in selecting species for the phytoremediation of orefield.
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