Mammalian oocytes not fertilized immediately after ovulation can undergo ageing and a rapid decline in quality. The addition of antioxidants can be an efficient approach to delaying the oocyte ageing process. Onion peel extract (OPE) contains quercetin and other flavonoids with natural antioxidant activities. In this study, we investigated the effect of OPE on mouse oocyte ageing and its mechanism of action. The oocytes were aged in vitro in M16 medium for 16 h after adding OPE at different concentrations (0, 50, 100, 200, and 500 μg/ml). The addition of 100 μg/ml OPE reduced the oocyte fragmentation rate, decreased the reactive oxygen species (ROS) level, increased the glutathione (GSH) level, and improved the mitochondrial membrane potential compared with the control group. The addition of OPE also increased the expression of SOD1, CAT, and GPX3 genes, and the caspase-3 activity in OPE-treated aged oocytes was significantly lower than that in untreated aged oocytes and similar to that in fresh oocytes. These results indicated that OPE delayed mouse oocyte ageing by reducing oxidative stress and apoptosis and enhancing mitochondrial function.

Climbing robots that use bionic claws can climb vertical or even inverted rough surfaces. However, wall-climbing robots with unidirectional spiny feet cannot crawl horizontally or downward on vertical rough surfaces. In this paper, a pair of gripping spiny feet is used to give a robot the capacity to crawl in any direction on a rough wall. On the basis of observations of the gecko’s method for grasping onto a vertical rough surface, a multilevel interlocking structure is proposed. A spherical contact model of the claw tip on a vertical rough surface is established, and the influences of the contact angle, friction coefficient, and other factors on the grappling claw action are analyzed. Moreover, the optimal structure of the grappling claws is proposed. The force during the grasping and detachment of the mechanism and the influence of the number of feet on grasping performance are determined through experiments. Furthermore, a six-legged wall-climbing robot is designed and evaluated in terms of crawling on a vertical rough surface at various angles. The feasibility of using an opposed gripping mechanism to allow a robot to crawl in any direction on a vertical rough surface is also verified.

For individual cultures, findings on regulating embryo density by changing the microdrop volume are contradictory. The aim of this study was to investigate the relationship between embryo density and the developmental outcome of day 3 embryos after adjusting covariates. In total, 1196 embryos from 206 couples who had undergone in vitro fertilization treatment were analyzed retrospectively. Three embryo densities were used routinely, i.e. one embryo in a drop (30 μl/embryo), two embryos in a drop (15 μl/embryo) and three embryos in a drop (10 μl/embryo). Embryo quality on day 3 was evaluated, both the cell number of day 3 embryos and the proportion of successful implantations served as endpoints. Maternal age, paternal age, antral follicles and level of anti-Müllerian hormone, type of infertility, controlled ovarian stimulation protocol, length of stimulation, number of retrieved oocytes, number of zygotes (two pronuclei) and insemination type were covariates and adjusted. After adjusting fully for all covariates, the cell number of day 3 embryos was significantly increased by 0.40 (95% CI 0.00, 0.79; P = 0.048) and 0.78 (95% CI 0.02, 1.54; P = 0.044) in the 15 μl/embryo and 10 μl/embryo group separately, compared with the 30 μl/embryo group. The proportions of implanted embryos were 42.1%, 48.7% and 0.0% in the 30 μl/embryo, 15 μl/embryo and 10 μl/embryo groups respectively. There was no statistical significance (P = 0.22) between the 30 μl/embryo group and the 15 μl/embryo group. After adjusting for confounders that were significant in univariate analysis, embryo density was still not associated with day 3 embryo implantation potential (P > 0.05). In a 30-μl microdrop, culturing embryos with an embryo density of both 15 and 10 μl/embryo increased the cell number of day 3 embryos, which did not benefit embryo implanting potential, compared with individual culture of 30 μl/embryo.

The effect of vitamin D (VD) on the risk of preeclampsia (PE) is uncertain. Few of previous studies focused on the relationship between dietary VD intake and PE risk. Therefore, we conducted this 1:1 matched case–control study to explore the association of dietary VD intake and serum VD concentrations with PE risk in Chinese pregnant women. A total of 440 pairs of participants were recruited during March 2016 to June 2019. Dietary information was obtained using a seventy-eight-item semi-quantitative FFQ. Serum concentrations of 25(OH)D2 and 25(OH)D3 were measured by liquid chromatography–tandem MS. Multivariate conditional logistic regression was used to estimate OR and 95 % CI. Restricted cubic splines (RCS) were plotted to evaluate the dose–response relationship of dietary VD intake and serum VD concentrations with PE risk. Compared with the lowest quartile, the OR of the highest quartile were 0·45 (95 % CI 0·29, 0·71, Ptrend = 0·001) for VD dietary intake and 0·26 (95 % CI 0·11, 0·60, Ptrend = 0·003) for serum levels after adjusting for confounders. In addition, the RCS analysis suggested a reverse J-shaped relationship between dietary VD intake and PE risk (P-nonlinearity = 0·02). A similar association was also found between serum concentrations of total 25(OH)D and PE risk (P-nonlinearity = 0·02). In conclusion, this study provides evidence that higher dietary intake and serum levels of VD are associated with the lower risk of PE in Chinese pregnant women.

The Antarctic subglacial drilling rig (ASDR) is designed to recover 105 mm-diameter ice cores up to 1400 m depth and 41.5 mm-diameter bedrock cores up to 2 m in length. In order to ensure safe and convenient drilling, drilling auxiliaries are designed to support fieldwork and servicing. These auxiliaries are subdivided into several systems for power supply, drill tripping in the borehole, ice core and chip processing, and drill servicing and maintenance. The required equipment also includes two generators, a drilling winch with a cable, logging winch with a cable, control desk, pipe handler with a fixed clamp, chip chamber vibrator, centrifuge, emergency devices and fitting and electrical tools. Additionally, several environmental protective measures such as a new liquid-tight casing with a thermal casing shoe and a bailing device for recovering drilling fluid from the borehole were designed. Most of the auxiliaries were tested during the summer of 2018–2019 near Zhongshan Station, East Antarctica while drilling to the bedrock to a depth of 198 m.

A new, modified version of the cable-suspended Ice and Bedrock Electromechanical Drill (IBED) was designed for drilling in firn, ice, debris-rich ice and rock. The upper part of the drill is almost the same for all drill variants and comprises four sections: cable termination, a slip-ring section, an antitorque system and an electronic pressure chamber. The lower part of the IBED comprises an auger core barrel, reamers, a core barrel for ice/debris-ice drilling and a conventional geological single-tube core barrel or custom-made double-tube core barrel. First, the short and full-scale field versions of the IBED were tested at an outdoor testing stand and a testing facility with a 12.5 m-deep ice well. Then, in the 2018–2019 summer season, the IBED was tested in the field at a site ~12 km south of Zhongshan Station, East Antarctica, and a ~6 cm bedrock core was recovered from a 198 m-deep borehole. A total of 18 d was required to penetrate the ice sheet. The retrieved core samples of blue ice, basal ice and bedrock provided valuable information regarding the Earth's paleo-environment.

Surface modification with poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) is an effective method for improving hemocompatibility. Peptide GREDVY immobilized on Ti is of great benefit to endothelialization. Micropattern of PMPC and GREDVY can regulate cells distribution, behaviors, and nitric oxide (NO) release. Copper can be used as catalytic to release NO from a donor in vitro, which can inhibit platelets adhesion, activation, and aggregation. The Ti-PDA(Cu)-M/R(P) micropattern was fabricated with PMMPC-HD {PMMPC [monomer contain MPC and methacrylic acid (MA)] was cross-linked with hexamethylene diamine} and peptide Gly-Arg-Glu-Asp-Val-Tyr (GREDVY) using PDMS stamp, and it was characterized by SEM, FTIR, and XPS. The results demonstrated that the PMPC and peptide GREDVY were immobilized onto polydopamine successfully. Simultaneously, the copper existed in polydopamine was confirmed by XPS. The rate of NO release in vitro catalyzed by copper ions was 1.5–5.3 × 10−10 mol/(cm2 min). It will be beneficial to inhibiting platelets adhesion and proliferation of ECs.

The layer-by-layer self-assembly technology was adopted to prepare a new generation of supercapacitor electrode material, GOQDs@NiAl-LDH, between Ni–Al layered double hydroxide (LDH) and graphene oxide quantum dots (GOQDs). First, Ni–Al LDH was prepared by coprecipitation of nickel nitrate and aluminum nitrate and then delaminated by ultrasonication. Second, NiAl-LDH was combined with GOQDs that were prepared by a ball milling reaction using hexachlorobenzene as raw material. The electrochemical data indicate that the composite (OGL9) exhibits highest specific capacitance, large current charge and discharge characteristics, and excellent cycle stability when the content of GOQDs is 10%. And the specific capacitance of composite reaches to 869 F/g at the current density of 1 A/g. Moreover, the capacitance retention at 1 A/g discharge current condition is 69.6% after 2000 cycles. And the results indicate that the OGL9 can be a promising electrode material for supercapacitor applications.

A study of 7,388 consecutive patients after hepatic resection between 2011 and 2012 identified hepatolithiasis, cirrhosis, and intraoperative blood transfusion as the only independent risk factors of both incisional and organ/space surgical site infection (SSI). Patients with these conditions should be cared for with caution to lower SSI rates.

There is much interest in the recent years in the nanoscale metallic multilayered composite materials due to their unusual mechanical properties, such as very high flow strength and stable plastic flow to large strains. These unique mechanical properties have been proposed to result from the interface-dominated plasticity mechanisms in nanoscale composite materials. Studying how the dislocation configurations and densities evolve during deformation will be crucial in understanding the yield, work hardening, and recovery mechanisms in the nanolayered materials. In an effort to shed light on these topics, uniaxial compression experiments on nanoscale Cu/Nb single-crystal multilayer pillars using ex situ synchrotron-based Laue x-ray microdiffraction technique were conducted. Using this approach, we studied the nanoscale Cu/Nb multilayer pillars before and after uniaxial compression to about 14% of plastic strain and found significant Laue peak broadening in the Cu phase, which indicates storage of statistically stored dislocations, while no significant Laue peak broadening was observed in the Nb phase in the nanoscale multilayers. These observations suggest that at 14% plastic strain of the nanolayered pillars, the deformation was dominated by plasticity in the Cu nanolayers and elasticity or possibly a zero net plasticity (due to the possibility of annihilation of interface dislocations) in the Nb nanolayers.

The diatoms are an ecologically important group of algae that have been extensively studied by ecologists and taxonomists. However, the large-scale patterns of diatom distribution and the factors underlying this distribution are largely unknown. The aims of this study were to identify the large-scale spatial patterns of benthic diatom assemblages in Korean streams and rivers, and to assess the importance of numerous environmental factors on diatom distribution. We classified 720 study sites based on diatom flora. Benthic diatoms, water chemistry, altitude, and riparian land cover and use were characterized by multivariate analyses, Monte Carlo permutation tests, and indicator species analysis. In total, we identified 531 diatom taxa. Diatom assemblages were mostly dominated by species of the genera Achnanthes, Navicula, Nitzschia, Cocconeis, Fragilaria (Synedra included), Cymbella, Gomphonema, and Melosira. Cluster analysis partitioned all 720 sites into eight groups based on diatom species composition. Canonical correspondence analysis indicated that altitude, land cover and use, current velocity, electrical conductivity, and nutrient levels explained a significant amount of the variation in the composition of assemblages of benthic diatoms. At the national scale, a downstream ecological gradient was apparent, from fast-flowing, mostly oligotrophic highland streams to slow-flowing, mostly eutrophic lowland rivers. Our data suggest that spatial factors explain some of the variation in diatom distribution. The present investigation of the spatial patterns of benthic diatoms, the ecological determinants of diatom occurrence, and the identification of diatom indicator species contributes to development of a program for assessing the biological integrity of lotic ecosystems in Korea.

Anthropogenic land use within watersheds has substantial effects on aquatic habitats and biological communities. From September 2006 to December 2008, we investigated the effects of land use on benthic macroinvertebrate communities by comparing Song Stream and Odae Stream, two adjacent mountain streams in Korea whose watersheds have different land use patterns. Song Stream is significantly disturbed by agricultural activities in the watershed, whereas Odae Stream is relatively undisturbed and is surrounded by a well-conserved forest area. Song Stream had significantly higher levels of all nutrients and sediment-related factors due to the adjacent agricultural area. As a result, Song Stream had markedly lower species community indices, such as taxa richness and abundance. In Song Stream, macroinvertebrate scrapers and predators were most adversely affected, whereas collector-gatherers became a dominant group. Based on correlation and multivariate analyses, total dissolved solids had the strongest negative relationship with macroinvertebrate assemblages, followed by electrical conductivity, total nitrogen, and pH. The proportion of cobble in stream substrate was positively related to the richness and abundance of macroinvertebrates. Our results indicate that disturbances caused by agricultural land use, particularly sand deposition, had significant adverse effects on macroinvertebrate habitats and on the biotic integrity of benthic macroinvertebrate communities.

The (Pb1−xLax)TiO3, (PLT) thin films possessing good ferroelectric properties were successfully obtained by using metal-organic-decomposition (MOD) process, followed by furnace post-annealing at 600-700°C (60 min) or rapid thermal annealing (RTA) at 600-700°C (60 s). Excess Pb-species incorporated in precursors for compensating for the Pb-loss during MOD process results in pronounced modification on thin film's electrical properties. The leakage current is reduced from JL= 1 × 10−3 A/cm2 to 1 × 10−4 A/cm2 (at 400 kV/cm) and the remanent polarization is increased from Pr= 8.3 µ C/cm2 to 12.6 µC/cm2, when 10 mol% excess-Pb is added. On the other hand, larger La-content in PLT films results in more pronounced Pb-loss and induces larger leakage current, which significantly degrades the ferroelectric properties of the films. The best properties obtained for PLT films prepared by the MOD process are: Pr= 12.6 µC/cm2, Ec = 80 kV/cm and JL= 10−5 A/cm2 (at 400 kV/cm).