72 research outputs found
Ice-Water-Gas Interaction during Icebreaking by an Airgun Bubble
When an airgun releases high-pressure gas underwater below an ice plate, it is observed that a bubble is formed rapidly while the ice plate is broken fiercely. In order to study the ice-water-gas interaction during this transient and violent phenomenon, a set of laboratory-scale devices was designed and a series of icebreaking experiments were carried out. High-speed photography was used to capture the evolution of the bubble and the ice plate. It was found that the airgun bubble had a unique ‘pear’ shape compared with the spherical bubble generated by electric sparking. The pressure induced by the pulsation of the airgun bubble near a rigid wall was measured by the pressure sensor. The initial shockwave, oscillatory pressure peaks caused by the directional fast air injection, secondary shockwave, and pressure peak caused by the bubble jet impact were clearly recorded. Three damage patterns of ice plates were observed and corresponding reasons were analyzed. The influence of dimensionless parameters, such as airgun-ice distance (Formula presented.) and ice thickness (Formula presented.), was also investigated. The physical mechanism of ice-water-gas interaction was summarized
Advanced glycation end products accelerate ischemia/reperfusion injury through receptor of advanced end product/nitrative thioredoxin inactivation in cardiac microvascular endothelial cells.
The advanced glycation end products (AGEs) are associated with increased cardiac endothelial injury. However, no causative link has been established between increased AGEs and enhanced endothelial injury after ischemia/reperfusion. More importantly, the molecular mechanisms by which AGEs may increase endothelial injury remain unknown. Adult rat cardiac microvascular endothelial cells (CMECs) were isolated and incubated with AGE-modified bovine serum albumin (BSA) or BSA. After AGE-BSA or BSA preculture, CMECs were subjected to simulated ischemia (SI)/reperfusion (R). AGE-BSA increased SI/R injury as evidenced by enhanced lactate dehydrogenase release and caspase-3 activity. Moreover, AGE-BSA significantly increased SI/R-induced oxidative/nitrative stress in CMECs (as measured by increased inducible nitric oxide synthase expression, total nitric oxide production, superoxide generation, and peroxynitrite formation) and increased SI/R-induced nitrative inactivation of thioredoxin-1 (Trx-1), an essential cytoprotective molecule. Supplementation of EUK134 (peroxynitrite decomposition catalyst), human Trx-1, or soluble receptor of advanced end product (sRAGE) (a RAGE decoy) in AGE-BSA precultured cells attenuated SI/R-induced oxidative/nitrative stress, reduced SI/R-induced Trx-1 nitration, preserved Trx-1 activity, and reduced SI/R injury. Our results demonstrated that AGEs may increase SI/R-induced endothelial injury by increasing oxidative/nitrative injury and subsequent nitrative inactivation of Trx-1. Interventions blocking RAGE signaling or restoring Trx activity may be novel therapies to mitigate endothelial ischemia/reperfusion injury in the diabetic population
Advanced Glycation End Products Accelerate Ischemia/Reperfusion Injury Through Receptor of Advanced End Product/Nitrative Thioredoxin Inactivation in Cardiac Microvascular Endothelial Cells
The Relationship Between Cognitive Dysfunction and Symptom Dimensions Across Schizophrenia, Bipolar Disorder, and Major Depressive Disorder
Background: Cognitive dysfunction is considered a core feature among schizophrenia (SZ), bipolar disorder (BD), and major depressive disorder (MDD). Despite abundant literature comparing cognitive dysfunction among these disorders, the relationship between cognitive dysfunction and symptom dimensions remains unclear. The study aims are a) to identify the factor structure of the BPRS-18 and b) to examine the relationship between symptom domains and cognitive function across SZ, BD, and MDD.Methods: A total of 716 participants [262 with SZ, 104 with BD, 101 with MDD, and 249 healthy controls (HC)] were included in the study. One hundred eighty participants (59 with SZ, 23 with BD, 24 with MDD, and 74 HC) completed the MATRICS Consensus Cognitive Battery (MCCB), and 507 participants (85 with SZ, 89 with BD, 90 with MDD, and 243 HC) completed the Wisconsin Card Sorting Test (WCST). All patients completed the Brief Psychiatric Rating Scale (BPRS).Results: We identified five BPRS exploratory factor analysis (EFA) factors (“affective symptoms,” “psychosis,” “negative/disorganized symptoms,” “activation,” and “noncooperation”) and found cognitive dysfunction in all of the participant groups with psychiatric disorders. Negative/disorganized symptoms were the most strongly associated with cognitive dysfunctions across SZ, BD, and MDD.Conclusions: Our findings suggest that cognitive dysfunction severity relates to the negative/disorganized symptom domain across SZ, BD, and MDD, and negative/disorganized symptoms may be an important target for effective cognitive remediation in SZ, BD, and MDD
Role of Human-Mediated Dispersal in the Spread of the Pinewood Nematode in China
Background: Intensification of world trade is responsible for an increase in the number of alien species introductions. Human-mediated dispersal promotes not only introductions but also expansion of the species distribution via long-distance dispersal. Thus, understanding the role of anthropogenic pathways in the spread of invading species has become one of the most important challenges nowadays. Methodology/Principal Findings: We analysed the invasion pattern of the pinewood nematode in China based on invasion data from 1982 to 2005 and monitoring data on 7 locations over 15 years. Short distance spread mediated by long-horned beetles was estimated at 7.5 km per year. Infested sites located further away represented more than 90% of observations and the mean long distance spread was estimated at 111–339 km. Railways, river ports, and lakes had significant effects on the spread pattern. Human population density levels explained 87% of the variation in the invasion probability (P,0.05).Since 2001, the number of new records of the nematode was multiplied by a factor of 5 and the spread distance by a factor of 2. We combined a diffusion model to describe the short distance spread with a stochastic,individual based model to describe the long distance jumps. This combined model generated an error of only 13% when used to predict the presence of the nematode. Under two climate scenarios (stable climate or moderate warming), projections of the invasion probability suggest that this pest could expand its distribution 40–55% by 2025. Conclusions/Significance: This study provides evidence that human-induced dispersal plays a fundamental role in the spread of the pinewood nematode, and appropriate control measures should be taken to stop or slow its expansion. This model can be applied to Europe, where the nematode had been introduced later, and is currently expanding its distribution. Similar models could also be derived for other species that could be accidentally transported by humans
The Corrosion Behavior of As-cast Mg–4Al–xEr–0.3Mn Alloys
Magnesium and magnesium alloys are light-weighting candidates as the structure materials. The microstructure and corrosion behavior of Mg–4Al–xEr–0.3Mn (x = 2, 4, 6 all in wt%) alloys were studied. The results showed that the morphology, size and distribution of Mg17Al12 phase were gradually improved with the increasing of Er content, and a large number of Al2Er were observed. The Al2Er inhibited the hydrogen evolution reaction and promoted the growth of passivation film. Er oxides or hydroxides were found on the surface of the passivation film, and the charge transfer resistance of the film was 4447 Ω cm2, while the film resistance was 5852 Ω cm2, which reduced the electron transfer efficiency and improved the density and stability of the passivation film, thus greatly improving the corrosion resistance. As Er content reaches 6 wt%, the corrosion rate decreases by nearly 45 %
Seasonal Variation and Global Public Interest in the Internet Searches for Osteoporosis
Background. To ascertain the seasonal pattern and global public interest in osteoporosis by evaluating search term popularity changes of the disease over a decade. Methods. We applied Google Trends to retrieve search popularity scores for the term “osteoporosis” between January 01, 2004, and December 31, 2019. Cosinor analyses were conducted to examine the seasonality of osteoporosis, and analysis on osteoporosis-related topics including hot topics and rising-related topics was also performed. Results. The cosinor analyses demonstrated a statistically significant seasonal variation in relative search volume of the “osteoporosis” in the world (p=0.0083), USA (p<0.001), UK (p<0.001), Canada (p<0.001), Ireland (p<0.001), Australia (p<0.001), and New Zealand (p<0.001), with a peak in the late winter months and trough in the summer months. The peaks in late winter and valley in summer presented an approximately 6-month difference between hemispheres. The top 11 rising topics were denosumab, FRAX, hypocalcaemia, zoledronic acid, ibandronic acid, osteomyelitis, osteopenia, osteoarthritis, bone, calcium, and bone density. Conclusions. Google search query volumes related to osteoporosis follow strong seasonal patterns with late winter peaks and summer troughs. Further studies aimed at elucidating the possible mechanisms behind seasonality in osteoporosis are needed. Moreover, Internet data including the top rising topics may alert physicians to strengthen the propaganda of osteoporosis timely, so as to further promote the development of public health interventions
Simulation Evaluation of Fast Frequency Response Capacity of New Energy Power Stations
The number of new energy power stations in China is boosting in recent years, a large number of conventional power supplies have been replaced, resulting in severe problems in controlling the frequency of power grids and easily leading to frequency issues of the state power grid. When large frequency disturbance occurs in power grid, renewable energy stations can participate in primary frequency regulation of power grid and provide support for system frequency, and the primary frequency regulation capability of the large power grid in sending end is significantly enhanced. In this study, a simulation evaluation method was proposed for the FFR controller of new energy power stations based on the RT-LAB real-time simulation analysis platform. The FFR controller was connected to in the simulation model of the state power grid via I/O physical interfaces and MODBUS communication, so as to conduct the step disturbance test, anti-disturbance performance verification test and automatic generation control (AGC) coordination test and hardware-in-the-loop simulation test of the controller. Results of the tests proved that the test method proposed in this study is accurate and reliable, and help improve the performance of a new energy power station in the state power grid
Biallelic variants in SLC26A2 cause multiple epiphyseal dysplasia-4 by disturbing chondrocyte homeostasis
Abstract Background Multiple epiphyseal dysplasia-4 (MED-4, MIM 226900) is a rare autosomal recessive disease characterized by disproportionate height and early onset osteoarthritis of the lower limbs. MED-4 is caused by homozygous or compound heterozygous pathogenic variants in the SLC26A2 gene. However, the underlying pathogenic mechanisms in chondrocytes remains unknown. This study aimed to identify the pathogenic variants within a MED-4 family and explore the molecular etiology of this condition in human primary chondrocyte cells. Methods Clinical data were recorded and peripheral blood samples were collected for analysis. Whole exome sequencing (WES) and bioinformatic analyses were performed to determine causative variants. Wild-type SLC26A2 and corresponding mutant expression plasmids were constructed and transfected into human primary chondrocytes. The expression and subcellular distribution of SLC26A2 protein in chondrocytes were detected by immunoblotting and immunofluorescence. Effects of these variants on chondrocytes viability and apoptosis were measured by Cell Counting Kit-8 (CCK-8) assay. Expression of genes related to cartilage homeostasis was subsequently analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). Results We identified two compound heterozygous variants c.1020_1022delTGT(p.Val341del) and c.1262 T > C(p.Ile421Thr) in the SLC26A2 gene in the patients. Mutant SLC26A2Val341del and SLC26A2Ile421Thr proteins were distributed in relatively few cells and were observed only within the nucleus. The viability of chondrocytes with the SLC26A2 variant group was similar to the wild-type (WT) group. However, the protein expressions of SLC26A2Val341del and SLC26A2Ile421Thr were decreased compared with SLC26A2WT. Expression levels of matrix metallopeptidase 13 (MMP13), α-1 chain of type X collagen (COL10A1), and Runt-related transcription factor 2 (RUNX2) were significantly decreased in the variant group. However, aggrecan (ACAN) expression was higher in the variant group than the WT group. Conclusions Overall, our data demonstrate that the variants p.Val341del and p.Ile421Thr in SLC26A2 cause MED-4 and that these two variants promote chondrocyte proliferation while inhibiting chondrocyte differentiation
Mapping of QTL for Chlorophyll Content in Rice on High-Density Bin Map
【Objective】The research explored the genetic mechanism for regulating chlorophyll content and its response to nitrogen (N) fertilizer in rice, and provide new molecular marker segments for breeding of high-yield and nitrogen- efficient rice varieties.【Method】The 113 family lines of ZS 97 × MH 63 recombinant inbred lines (RIL, F11) were adopted as tested materials for QTL analysis. Field experiments were performed with split-plot design, N fertilizer rate being the main plots and RIL being subplots. The low N (no N) and normal N (130, 135 N kg/hm2) fertilizer treatments were established in the fields. The chlorophyll meter was used to determine SPAD values of leaves at 30 days after transplanting (30 DAT) and at heading (HD) stage. By using a high-density genetic map containing 1 619 Bin markers, IciMappingv3.4 software and complete interval mapping, QTL for controlling leaf chlorophyll content at two growth stages was mapped.【Result】In two N treatments at two growth stages within two years, a total of 15 QTLs for controlling leaf chlorophyll content were detected and they were located on chromosomes 1, 2, 3, 6, 7, 10 and 11. Each single QTL could explain 1.21%-40.74% of genetic contributions to traits. Through comparison of their physical loci, 6 QTLs were found to have been cloned or have the same loci being known previously for chlorophyll content. Among them, a locus, named qHDCHL6-1, regulating the chlorophyll content of flag leaf at heading stage was detected at 8.45-9.12Mb of chromosome 6. It was stably detected under two N treatments in two years, which explained 1.55%-28.01% of contributions to traits. Through functional annotation, 4 candidate genes related to chlorophyll content of flag leaf were found in the qHDCHL6-1 chromosome interval. These genes were LOC_Os06g15370 (OsNPF3.1), LOC_Os06g15420 (OsAS2), LOC_Os06g15620 (GAS) and LOC_Os06g15590, and the first three of these genes have been cloned【Conclusion】15 QTLs controlling leaf chlorophyll content of rice at 30 DAT and HD stage are detected, and a QTL locus qHDCHL6-1 with stable expression was identified, which contains 4 candidate genes
- …