Memory deficit in patients with cerebral small vessel disease: evidence from eye tracking technology.

Cerebral small vessel disease is the one of the most prevalent causes of vascular cognitive impairment. We aimed to find objective and process-based indicators related to memory function to assist in the detection of memory impairment in patients with cerebral small vessel disease. Thirty-nine cerebral small vessel disease patients and 22 healthy controls were invited to complete neurological examinations, neuropsychological assessments, and eye tracking tasks. Eye tracking indicators were recorded and analyzed in combination with imaging features. The cerebral small vessel disease patients scored lower on traditional memory task and performed worse on eye tracking memory task performance compared to the healthy controls. The cerebral small vessel disease patients exhibited longer visit duration and more visit count within areas of interest and targets and decreased percentage value of total visit duration on target images to total visit duration on areas of interest during decoding stage among all levels. Our results demonstrated the cerebral small vessel disease patients performed worse in memory scale and eye tracking memory task, potentially due to their heightened attentional allocation to nontarget images during the retrieval stage. The eye tracking memory task could provide process-based indicators to be a beneficial complement to memory assessment and new insights into mechanism of memory impairment in cerebral small vessel disease patients.

Preservation of the celiac branch of the vagus nerve reduces the incidence of postoperative diarrhea in gastric cancer: a cohort study.

BACKGROUND: To investigate the short-term and long-term outcomes of preserving the celiac branch of the vagus nerve during laparoscopic distal gastrectomy. METHODS: A total of 149 patients with prospective diagnosis of gastric cancer who underwent laparoscopic-assisted distal gastrectomy (LADG) combined with Billroth-II anastomosis and D2 lymph node dissection between 2017 and 2018 were retrospectively analyzed. The patients were divided into the preserved LADG group (P-LADG, n = 56) and the resected LADG group (R-LADG, n = 93) according to whether the vagus nerve celiac branch was preserved. We selected 56 patients (P-LADG, n = 56) with preservation of the celiac branch of the vagus nerve and 56 patients (R-LADG, n = 56) with removal of the celiac branch of the vagus nerve by propensity-matched score method. Postoperative nutritional status, weight change, short-term and long-term postoperative complications, and gallstone formation were evaluated in both groups at 5 years of postoperative follow-up. The status of residual gastritis and bile reflux was assessed endoscopically at 12 months postoperatively. RESULTS: The incidence of diarrhea at 5 years postoperatively was lower in the P-LADG group than in the R-LADG group (p < 0.05). In the multivariate logistic analysis, the removal of vagus nerve celiac branch was an independent risk factor for the occurrence of postoperative diarrhea (odds ratio = 3.389, 95% confidential interval = 1.143-10.049, p = 0.028). In the multivariate logistic analysis, the removal of vagus nerve celiac branch was an independent risk factor for the occurrence of postoperative diarrhea (odds ratio = 4.371, 95% confidential interval = 1.418-13.479, p = 0.010). CONCLUSIONS: Preservation of the celiac branch of the vagus nerve in LADG reduced the incidence of postoperative diarrhea postoperatively in gastric cancer. TRIAL REGISTRATION: This study was registered with the Ethics Committee of the First Affiliated Hospital of Dalian Medical University in 2014 under the registration number: LCKY2014-04(X).

Dietary protein sources, genetics, and cardiovascular disease incidence.

BACKGROUND: To explore the potential correlation between the amount and source of dietary protein and cardiovascular disease (CVD), as well as the potential impact of genetic susceptibility on these connections. METHODS: We performed a prospective analysis of 98,224 participants from the UK. We measured dietary protein intake using two 24-hour dietary recall interviews. To analyze the data, we used multivariable-adjusted Cox regression models and restricted cubic spline models. Additionally, we calculated weighted genetic risk scores. RESULTS: A total of 8818 new cases of CVD were documented, which included 4076 cases of coronary artery disease (CAD) and 1126 cases of stroke. The study found a J-shaped association (p nonlinearity = 0.005) between CVD risk and the percentage of energy obtained from consuming plant protein. Higher intake of plant protein and whole protein was associated with a decreased risk of CVD. On the other hand, larger intakes of animal protein was linked to a higher occurrence of CAD. Additionally, increased intake of plant protein was also linked to a lower incidence of stroke. Replacing 5 % of animal protein-based energy intake with plant protein-based energy intake resulted in a 5 % decrease in CVD risk. LIMITATIONS: There remains an effect of residual confounders. CONCLUSION: The consumption of larger amounts of plant protein, whole protein, and nut protein was found to be associated with a lower risk of CVD events. Conversely, higher intakes of animal protein was associated with an increased risk of CAD events. Furthermore, replacing 5 % of energy intake from animal protein with energy intake from plant protein was found to reduce the risk of CVD by 5 %.

Frontal lobe epilepsy: an eye tracking study of memory and attention.

Objective: To explore the characteristics and mechanisms of working memory impairment in patients with frontal lobe epilepsy (FLE) through a memory game paradigm combined with eye tracking technology. Method: We included 44 patients with FLE and 50 healthy controls (HC). All participants completed a series of neuropsychological scale assessments and a short-term memory game on an automated computer-based memory evaluation platform with an eye tracker. Results: Memory scale scores of FLE patients including digit span (U = 747.50, p = 0.007), visual recognition (U = 766.50, p = 0.010), and logical memory (U = 544.00, p < 0.001) were significantly lower than HC. The patients with FLE took longer to complete the four levels of difficulty of the short-term memory game than healthy controls (level 1: U = 2974.50, p = 0.000; level 2: U = 3060.50, p = 0.000; level 3: U = 2465.00, p = 0.000; level 4: U = 2199.00, p = 0.000). During the memory decoding period, first fixation on the targets took significantly longer for FLE patients for all difficulty levels compared to controls (level 1: U = 3407.00, p = 0.008; level 2: U = 3618.00, p = 0.036; level 3: U = 3345.00, p = 0.006; level 4: U = 2781.00, p = 0.000). The average fixation duration per target among patients with FLE was found to be significantly longer compared to HC (level 1: U = 2994.50, p = 0.000; level 2: U = 3101.00, p = 0.000; level 3: U = 2559.50, p = 0.000; level 4: U = 2184.50, p = 0.000). The total fixation duration on AOI/total completion time of FLE patients was significantly lower than those of HC for levels 1 to 3 (level 1: U = 1557.00, p = 0.000; level 2: U = 2333.00, p = 0.000; level 3: U = 2757.00, p = 0.000). Furthermore, the eye tracking data during the memory decoding phase were correlated with neuropsychological scale scores (p < 0.05). Conclusion: Patients with FLE exhibited short-term memory impairment probably due to deficits in attentional maintenance, especially during the memory decoding phase. Eye tracking technology provided the possibility to help separate and quantify visual attention from memory processing, contributing to exploring underlying mechanisms of memory impairment in FLE.

Deep neural network: As the novel pipelines in multiple preprocessing for Raman spectroscopy.

Raman spectroscopy is a kind of vibrational method that can rapidly and non-invasively gives chemical structural information with the Raman spectrometer. Despite its technical advantages, in practical application scenarios, Raman spectroscopy often suffers from interference, such as noises and baseline drifts, resulting in the inability to acquire high-quality Raman spectroscopy signals, which brings challenges to subsequent spectral analysis. The commonly applied spectral preprocessing methods, such as Savitzky-Golay smooth and wavelet transform, can only perform corresponding single-item processing and require manual intervention to carry out a series of tedious trial parameters. Especially, each scheme can only be used for a specific data set. In recent years, the development of deep neural networks has provided new solutions for intelligent preprocessing of spectral data. In this paper, we first creatively started from the basic mechanism of spectral signal generation and constructed a mathematical model of the Raman spectral signal. By counting the noise parameters of the real system, we generated a simulation dataset close to the output of the real system, which alleviated the dependence on data during deep learning training. Due to the powerful nonlinear fitting ability of the neural network, fully connected network model is constructed to complete the baseline estimation task simply and quickly. Then building the Unet model can effectively achieve spectral denoising, and combining it with baseline estimation can realize intelligent joint processing. Through the simulation dataset experiment, it is proved that compared with the classic method, the method proposed in this paper has obvious advantages, which can effectively improve the signal quality and further ensure the accuracy of the peak intensity. At the same time, when the proposed method is applied to the actual system, it also achieves excellent performance compared with the common method, which indirectly indicates the effectiveness of the Raman signal simulation model. The research presented in this paper offers a variety of efficient pipelines for the intelligent processing of Raman spectroscopy, which can adapt to the requirements of different tasks while providing a new idea for enhancing the quality of Raman spectroscopy signals.

Evaluating anti-viral effect of Tylvalosin tartrate on porcine reproductive and respiratory syndrome virus and analyzing the related gene regulation by transcriptomics.

BACKGROUND: Porcine reproductive and respiratory syndrome virus (PRRSV) is an economically important pathogen, characterized by its genetic and antigenic variation. The PRRSV vaccine is widely used, however, the unsatisfied heterologic protection and the risk of reverse virulence raise the requirement to find some new anti-PRRSV strategies for disease control. Tylvalosin tartrate is used to inhibit PRRSV in the field non-specifically, however, the mechanism is still less known. METHODS: The antiviral effects of Tylvalosin tartrates from three producers were evaluated in a cell inoculation model. Their safety and efficacy concentrations, and effecting stage during PRRSV infection were analyzed. And, the Tylvalosin tartrates regulated genes and pathways which are potentially related to the anti-viral effect were further explored by using transcriptomics analysis. Last, the transcription level of six anti-virus-related DEGs was selected to confirm by qPCR, and the expression level of HMOX1, a reported anti-PRRSV gene, was proved by western blot. RESULTS: The safety concentrations of Tylvalosin tartrates from three different producers were 40 µg/mL (Tyl A, Tyl B, and Tyl C) in MARC-145 cells and 20 µg/mL (Tyl A) or 40 µg/mL (Tyl B and Tyl C) in primary pulmonary alveolar macrophages (PAMs) respectively. Tylvalosin tartrate can inhibit PRRSV proliferation in a dose-dependent manner, causing more than 90% proliferation reduction at 40 µg/mL. But it shows no virucidal effect, and only achieves the antiviral effect via long-term action on the cells during the PRRSV proliferation. Furthermore, GO terms and KEGG pathway analysis was carried out based on the RNA sequencing and transcriptomic data. It was found that the Tylvalosin tartrates can regulate the signal transduction, proteolysis, and oxidation-reduction process, as well as some pathways such as protein digestion and absorption, PI3K-Akt signaling, FoxO signaling, and Ferroptosis pathways, which might relate to PRRSV proliferation or host innate immune response, but further studies still need to confirm it. Among them, six antivirus-related genes HMOX1, ATF3, FTH1, FTL, NR4A1, and CDKN1A were identified to be regulated by Tylvalosin tartrate, and the increased expression level of HMOX1 was further confirmed by western blot. CONCLUSIONS: Tylvalosin tartrate can inhibit PRRSV proliferation in vitro in a dose-dependent manner. The identified DEGs and pathways in transcriptomic data will provide valuable clues for further exploring the host cell restriction factors or anti-PRRSV target.

Quality of life and mortality in older adults with sepsis after one-year follow up: A prospective cohort study demonstrating the significant impact of frailty.

BACKGROUND: Survivors of sepsis often develop chronic critical illness after the inflammatory stage, resulting in death or hospital readmission. The long-term prognosis of older patients with sepsis and the associated factors, particularly frailty, are not well studied. OBJECTIVES: To investigate the effect of frailty on the quality of life (QoL) and mortality in older patients after one year of sepsis diagnosis. METHODS: This prospective study included patients admitted to a specialized geriatric intensive care unit between May 2018 and April 2019. Patients were grouped according to the Clinical Frailty Scale as severely frail, mildly to moderately frail, and non-frail/vulnerable. The primary outcome was QoL one year after sepsis diagnosis, measured using the European QoL 5-Dimension (EQ-5D) and 12-item Short Form. The secondary outcome was one-year survival. RESULTS: Of the 211 participants, 75 (35.5%) completed the QoL surveys. Of them, 37 (49.3%) did not return to their baseline QoL one year after sepsis diagnosis. The rate of reported mobility problems (a dimension of the EQ-5D) increased by 100% during the year. Additionally, survivors in the severely frail group exhibited poorer QoL at one year than those in the mildly to moderately frail and non-frail/vulnerable groups. The one-year mortality in the severely frail group was 75.9%, with an adjusted hazard ratio of 1.70 (95% confidence interval, 1.02-2.82, p = 0.041). CONCLUSIONS: Frailty significantly impacts the one-year prognosis in older patients with sepsis. This research highlights the need for frailty management and physical rehabilitation in frail older patients at risk of poor prognosis, with implications for improving transitional and post-acute care services.

Effects of histone methylation modification on low temperature seed germination and growth of maize.

Low temperature is a limiting factor of seed germination and plant growth. Although there is a lot information on the response of maize to low temperatures, there is still poorly description of how histone methylation affects maize germination and growth development at low temperatures. In this study, the germination rate and physiological indexes of wild-type maize inbred lines B73 (WT), SDG102 silencing lines (AS), SDG102 overexpressed lines (OE) at germination stage and seedling stage were measured under low temperature stress (4 â„ƒ), and transcriptome sequencing was applied to analyze the differences of gene expression in panicle leaves among different materials. The results showed that the germination rate of WT and OE maize seeds at 4 â„ƒ was significantly lower than 25 â„ƒ. The content of MDA, SOD and POD of 4 â„ƒ seeding leaves higher than contrast. Transcriptome sequencing results showed that there were 409 different expression genes (DEGs) between WT and AS, and the DEGs were mainly up-regulated expression in starch and sucrose metabolism and phenylpropanoid biosynthesis. There were 887 DEGs between WT and OE, which were mainly up-regulated in the pathways of plant hormone signal transduction, porphyrin and chlorophyll metabolism. This result could provide a theoretical basis for analyzing the growth and development of maize from the perspective of histone methylation modification.

A Reactive Molecular Dynamics Study on Crosslinked Epoxy Resin Decomposition under High Electric Field and Thermal Aging Conditions.

To reveal the microscopic mechanism of synergetic thermal-electrical degradation during a partial discharge process in epoxy insulation materials, the decomposition of crosslinked epoxy resin is investigated using reactive molecular dynamics simulations under high electric field and thermal degradation conditions. Bond-boost acceleration method is employed in reactive molecular dynamics simulations to successfully establish epoxy polymer models with a crosslink degree of 93%. Active molecular species derived from electrical partial discharges are considered in the current work. Small molecule products and decomposition temperature in the degradation process under an electric field are calculated to elucidate the effect of nitric acid and ozone molecules, being the active products generated by electrical partial discharges, on the synergetic thermal-electrical degradation of epoxy resin. Both nitric acid and ozone exacerbate thermal impact decomposition of crosslinked epoxy polymer by decreasing initial decomposition temperature from 1050 K to 940 K and 820 K, respectively. It is found that these active products can oxidize hydroxyl groups and carbon-nitrogen bridge bonds in epoxy molecular chains, leading to the aggravation of epoxy resin decomposition, as manifested by the significant increase in the decomposed molecular products. In contrast, thermal degradation of the epoxy resin without the active species is not expedited by increasing electric field. These strongly oxidative molecules are easily reduced to negative ions and able to obtain kinetic energies from electric field, which result in chemical corrosion and local temperature increase to accelerate decomposition of epoxy insulation materials.

Dielectric Characteristics of Crosslinked Polyethylene Modified by Grafting Polar-Group Molecules.

Polar group-modified crosslinked polyethylene (XLPE) materials are developed with a peroxide thermochemical method of individually grafting chloroacetic acid allyl ester (CAAE) and maleic anhydride (MAH) to polyethylene molecular-chains, which are dedicated to ameliorating dielectric characteristics through charge-trapping mechanism. By free radical addition reactions, the CAAE and MAH molecules are successfully grafted to polyethylene molecular chains of XLPE in crosslinking process, as verified by infrared spectroscopy molecular characterizations. Dielectric spectra, electric conductance, and dielectric breakdown strength are tested to evaluate the improved dielectric performances. Charge trap characteristics are investigated by analyzing thermal stimulation depolarization currents in combination with first-principles electronic-structure calculations to reveal the polar-group introduced mechanisms of contributing dipole dielectric polarization, impeding electric conduction, and promoting electrical breakdown field. The grafted polar-group molecules, especially for MAH, can introduce deep-level charge traps in XLPE materials to effectively restrict charge injections and hinder charge carrier transports, which accounts for the significant improvements in electric resistance and dielectric breakdown strength.

[Corrigendum] Role of cysteine­rich angiogenic inducer 61 in fibroblast­like synovial cell proliferation and invasion in rheumatoid arthritis.

Following the publication of the above article, an interested reader drew to the authors' attention that Fig. 4A on p. 921, showing the results from cell migration assay experiments, featured a pair of duplicated data panels. After having consulted their original data, the authors have realized that Fig. 3A on the same page, showing the fluorometric images of apoptotic cells, also contained a pair of duplicated data panels. These errors in the presentation of these figures arose inadvertently as a consequence of selecting the wrong images for the 'RA NC' data panel in Fig. 3A and the NOR-FLS data panel in Fig. 5E. The revised versions of Figs. 3 and 4 are shown on the next two pages. All the authors approve of the publication of this corrigendum, and the authors are grateful to the Editor of Molecular Medicine Reports for granting them the opportunity to publish this. The authors regret their oversight in allowing these errors to be included in the paper, and also apologize to the readership for any inconvenience caused. [Molecular Medicine Reports 11: 917­923, 2015; DOI: 10.3892/mmr.2014.2770].

Association between Coronary Heart Disease, Heart Failure, and Risk of Alzheimer's Disease: A Systematic Review and Meta-Analysis.

Background: Cardiovascular diseases such as coronary heart disease (CHD), heart failure (HF), and stroke have been linked to the development of Alzheimer's disease (AD). However, previous studies have reported inconsistent results. The study aimed to investigate the association between CHD, HF, and the risk of AD using a meta-analysis. Methods: STATA 12.0 software is used to compute odds ratios (ORs)/relative risks (RRs) and 95% confidence intervals (CIs) for the association between CHD, HF, and the risk of AD. Results: A total of 12 studies (including N = 36,913 individuals with AD and N = 1,701,718 participants) investigated the association between CHD and the risk of AD. Meta-analysis indicated that CHD was associated with an increased risk of AD with a random effects model (OR/RR: 1.22, 95% CI: 1.00-1.48, I2 = 97.2%, P < 0.001). Additionally, seven studies (including N = 5,119 individuals with AD and N = 1,231,399 participants) investigated the association between myocardial infarction (MI) and the risk of AD. Our meta-analysis demonstrated no significant association between MI and the risk of AD with a fixed effects model (RR: 1.09, 95% CI: 0.91-1.30, I2 = 42.8%, P = 0.105). Finally, six studies (including N = 83,065 individuals with AD and N = 2,414,963 participants) examined the association between HF and the risk of AD. Our meta-analysis revealed that HF was associated with an increased risk of AD using a random effects model (RR: 1.53, 95% CI: 1.05-2.24, I2 = 96.8%, P < 0.001). Conclusion: In conclusion, our meta-analysis suggests that CHD and HF are associated with an increased risk of developing AD. Nonetheless, more large-scale prospective studies are necessary to further investigate the associations between CHD, HF, and the risk of AD.

Direct Current Electrical Performances of Cable Accessory Insulation EPDM Modified by Grafting Polar-Group Compound.

In order to improve electrical matching between ethylene-propylene-diene misch-polymere (EPDM) reinforce insulation and crosslinked polyethylene (XLPE) main insulation in direct current (DC) cable accessories, the glyceryl monooleate (GMO) organic compound composed of several polar-groups and one long carbon chain is employed for chemical graft modification on EPDM to ameliorate DC electrical performances. Charge trap characteristics are analyzed by testing thermal stimulation current (TSC) and verified by calculating first-principles electronic properties to elucidate the GMO-graft-modified charge trapping mechanism accounting for DC electric conductance and dielectric breakdown. The grafted GMO molecules introduce substantial shallow charge traps that lead to nonlinear profiles of electric conduction versus electric field and cause hopping transports of percolation conductance. Electric conductance of EPDM is significantly improved by GMO graft for electrical matching with XLPE, while a high level of dielectric breakdown strength is retained sufficiently for reinforce insulation in cable accessories. Shallow charge traps introduced by GMO graft are capable of capturing charge carriers to form homocharge layers near electrodes which can scatter the transporting charge carriers and exclude further charge injections, thus to mitigate the dielectric breakdown strength reduction caused by electric conductivity improvement. Electric field finite-element simulations demonstrate that the electric field in DC cable terminals can be evidently homogenized by using GMO-grafted EPDM as reinforce insulation.

Attenuated Porcine Reproductive and Respiratory Syndrome Virus Regains Its Fatal Virulence by Serial Passaging in Pigs or Porcine Alveolar Macrophages To Increase Its Adaptation to Target Cells.

Porcine reproductive and respiratory syndrome (PRRS) is a globally important disease threatening the pork industry, and modified live-virus (MLV) vaccines are widely used for its prevention. However, PRRS MLV shows high potential for reversion to virulence, leading to a major concern about its safety. Yet the revertant mechanism is still poorly understood. Here, attenuated virus JXwn06-P80, derived from the highly pathogenic PRRS virus (PRRSV) strain JXwn06 by serial passaging in MARC-145 cells, was reversely passaged in pigs through intranasal inoculation to mimic natural infection for 13 rounds, and the pathogenicity of viruses at the 3rd, 5th, 9th, 10th, and 11th passages was evaluated in pigs. From the 9th passage, the viruses caused mortality, which was related to their increased adaptability and replication efficiency (100 times higher than those of JXwn06-P80) in porcine alveolar macrophage (PAM) target cells. Similarly, JXwn06-P80 could also regain fatal virulence through reverse passage in PAMs for 25 or more passages, indicating that the increased adaptability in PAMs directly contributes to its regained fatal virulence. Next, the full-genome sequences were analyzed to explore the genetic evolutionary processes during adaptation both in vivo and in vitro. Finally, by a reverse genetic operation, four reverse mutation sites, NSP12-W121R, ORF2b (open reading frame 2b)-H9D, ORF5-H15L, and ORF5-V189L, were finally identified to partially contribute to the ability of the virus to adapt to PAMs, which may be related to virulence reversion during reverse passage. These findings provided direct scientific evidence for the virulence reversion of PRRS MLV and provided valuable clues for exploring its molecular mechanism. IMPORTANCE Reversion to virulence of a live attenuated vaccine is a public concern; however, direct scientific evidence is limited, and the mechanism is still poorly understood. Here, we present direct evidence for the reversion to virulence of PRRS MLV after serial passaging in pigs or target cells and found a correlation between virulence reversion and increased replication fitness in primary PAMs. The genetic evolutionary process during adaptation will provide valuable clues for exploring the molecular mechanism of PRRS MLV virulence reversion and offer important implications for understanding the reversion mechanisms of other vaccines.

Electrical Insulation and Radar-Wave Absorption Performances of Nanoferrite/Liquid-Silicone-Rubber Composites.

Novel radar-wave absorption nanocomposites are developed by filling the nanoscaled ferrites of strontium ferroxide (SrFe12O19) and carbonyl iron (CIP) individually into the highly flexible liquid silicone rubber (LSR) considered as dielectric matrix. Nanofiller dispersivities in SrFe12O19/LSR and CIP/LSR nanocomposites are characterized by scanning electronic microscopy, and the mechanical properties, electric conductivity, and DC dielectric-breakdown strength are tested to evaluate electrical insulation performances. Radar-wave absorption performances of SrFe12O19/LSR and CIP/LSR nanocomposites are investigated by measuring electromagnetic response characteristics and radar-wave reflectivity, indicating the high radar-wave absorption is dominantly derived from magnetic losses. Compared with pure LSR, the SrFe12O19/LSR and CIP/LSR nanocomposites represent acceptable reductions in mechanical tensile and dielectric-breakdown strengths, while rendering a substantial nonlinearity of electric conductivity under high electric fields. SrFe12O19/LSR nanocomposites provide high radar-wave absorption in the frequency band of 11~18 GHz, achieving a minimum reflection loss of -33 dB at 11 GHz with an effective absorption bandwidth of 10 GHz. In comparison, CIP/LSR nanocomposites realize a minimum reflection loss of -22 dB at 7 GHz and a remarkably larger effective absorption bandwidth of 3.9 GHz in the lower frequency range of 2~8 GHz. Radar-wave transmissions through SrFe12O19/LSR and CIP/LSR nanocomposites in single- and double-layered structures are analyzed with CST electromagnetic-field simulation software to calculate radar reflectivity for various absorbing-layer thicknesses. Dual-layer absorbing structures are modeled by specifying SrFe12O19/LSR and CIP/LSR nanocomposites, respectively, as match and loss layers, which are predicted to acquire a significant improvement in radar-wave absorption when the thicknesses of match and loss layers approach 1.75 mm and 0.25 mm, respectively.

Water-Tree Characteristics and Its Mechanical Mechanism of Crosslinked Polyethylene Grafted with Polar-Group Molecules.

In order to restrain electric-stress impacts of water micro-droplets in insulation defects under alternating current (AC) electric fields in crosslinked polyethylene (XLPE) material, the present study represents chemical graft modifications of introducing chloroacetic acid allyl ester (CAAE) and maleic anhydride (MAH) individually as two specific polar-group molecules into XLPE material with peroxide melting approach. The accelerated water-tree aging experiments are implemented by means of a water-blade electrode to measure the improved water resistance and the affording mechanism of the graft-modified XLPE material in reference to benchmark XLPE. Melting−crystallization process, dynamic viscoelasticity and stress-strain characteristics are tested utilizing differential scanning calorimeter (DSC), dynamic thermomechanical analyzer (DMA) and electronic tension machine, respectively. Water-tree morphology is observed for various aging times to evaluate dimension characteristics in water-tree developing processes. Monte Carlo molecular simulations are performed to calculate free-energy, thermodynamic phase diagram, interaction parameter and mixing energy of binary mixing systems consisting of CAAE or MAH and water molecules to evaluate their thermodynamic miscibility. Water-tree experiments indicate that water-tree resistance to XLPE can be significantly improved by grafting CAAE or MAH, as indicated by reducing the characteristic length of water-trees from 120 to 80 µm. Heterogeneous nucleation centers of polyethylene crystallization are rendered by the grafted polar-group molecules to ameliorate crystalline microstructures, as manifested by crystallinity increment from 33.5 to 36.2, which favors improving water-tree resistance and mechanical performances. The highly hydrophilic nature of CAAE can evidently inhibit water molecules from aggregating into water micro-droplets in amorphous regions between crystal lamellae, thus acquiring a significant promotion in water-tree resistance of CAAE-modified XLPE. In contrast, the grafted MAH molecules can enhance van der Waals forces between polyethylene molecular chains in amorphous regions much greater than the grafted CAAE and simultaneously act as more efficient crystallization nucleation centers to ameliorate crystalline microstructures of XLPE, resulting in a greater improvement (relaxation peak magnitude increases by >10%) of mechanical toughness in amorphous phase, which primarily accounts for water-tree resistance promotion.

SDG102, a H3K36-Methyltransferase-Encoding Gene, Plays Pleiotropic Roles in Growth and Development of Maize (Zea mays L.).

Although histone lysine methylation has been studied in thale cress (Arabidopsis thaliana (L.) Heynh.) and rice (Oryza sativa L.) in recent years, its function in maize (Zea mays L.) remains poorly characterized. To better understand the function of histone lysine methylation in maize, SDG102, a H3 lysine 36 (H3K36) methylase, was chosen for functional characterization using overexpressed and knockout transgenic plants. SDG102-deficiency in maize caused multiple phenotypes including yellow leaves in seedlings, late-flowering, and increased adult plant height, while the overexpression of SDG102 led to reduced adult plant height. The key flowering genes, ZCN8/ZCN7 and MADS4/MADA67, were downregulated in SDG102-deficient plants. Chromatin immunoprecipitation (ChIP) experiments showed that H3 lysine 36 trimethylation (H3K36me3) levels were reduced at these loci. Perturbation of SDG102 expression caused the misexpression of multiple genes. Interestingly, the overexpression or knockout of SDG102 also led to genome-wide decreases and increases in the H3K36me3 levels, respectively. Together, our results suggest that SDG102 is a methyltransferase that catalyzes the trimethylation of H3K36 of many genes across the maize genome, which are involved in multiple biological processes including those controlling flowering time.

Magnetic Force Probe Characterizations of Nanoscaled Ferromagnetic Domains: Finite-Element Magnetostatic Simulations.

Microscopic characterization of magnetic nanomaterials by magnetic probe interacting with ferromagnetic nano-domains is proposed according to finite-element magnetostatic field simulations. Magnetic forces detected by microscopic probe are systematically investigated on magnetic moment orientation, magnetization intensity and geometry of ferromagnetic nano-domains, and especially on permanent magnetic coating thickness and tilting angle of probe, to provide a theoretical basis for developing magnetic force microscopy. Magnetic force direction is primarily determined by magnetic moment orientation of nanosample, and the tip curvature dominates magnetic force intensity that is meanwhile positively correlated with nanosample magnetization and probe magnetic coating thickness. Nanosample should reach a critical thickness determined by its transverse diameter to be capable of accurately detecting the magnetic properties of ferromagnetic nanomaterials. Magnetic force signal relies on probe inclination when the sample magnetic moment is along probe tilting direction, which, however, is not disturbed by probe inclination when sample magnetic moment is perpendicular to probe tilting plane. Within the geometry of satisfying a critical size requirement, the magnetic force can successfully image the ferromagnetic nano-domains by characterizing their sizes and magnetic moment orientations. The present study is expected to provide effective analyzing schemes and theoretical evidences for magnetic force microscopy of characterizing magnetic structures in ferromagnetic nanomaterials.

Nonlinear Conductivity and Space Charge Characteristics of SiC/Silicone Rubber Nanocomposites.

To achieve a preferable compatibility between liquid silicone rubber (LSR) and cable main insulation in a cable accessory, we developed SiC/LSR nanocomposites with a significantly higher conductivity nonlinearity than pure LSR, whilst representing a notable improvement in space charge characteristics. Space charge distributions in polarization/depolarization processes and surface potentials of SiC/LSR composites are analyzed to elucidate the percolation conductance and charge trapping mechanisms accounting for nonlinear conductivity and space charge suppression. It is verified that SiC/LSR composites with SiC content higher than 10 wt% represent an evident nonlinearity of electric conductivity as a function of the electric field strength. Space charge accumulations can be inhibited by filling SiC nanoparticles into LSR, as illustrated in both dielectric polarization and depolarization processes. Energy level and density of shallow traps increase significantly with SiC content, which accounts for expediting carrier hopping transport and surface charge decay. Finite-element multiphysics simulations demonstrate that nonlinear conductivity acquired by 20 wt% SiC/LSR nanocomposite could efficiently homogenize an electric field distributed in high-voltage direct current (HVDC) cable joints. Nonlinear conductivities and space charge characteristics of SiC/LSR composites discussed in this paper suggest a feasible modification strategy to improve insulation performances of direct current (DC) cable accessories.