365 research outputs found

    Thinning and drilling laser-assisted hatching in thawed embryo transfer : A randomized controlled trial

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    Objective: In frozen and thawed embryos, the zona pellucida (ZP) can be damaged due to hardening. Laser-assisted hatching (LAH) of embryos can increase the pregnancy rate. This study compared thinning and drilling of the ZP before frozen embryo transfer (FET). Methods: Patients were randomly allocated into two groups for LAH using thinning or drilling on day 2 after thawing. Twenty-five percent of the ZP circumference and 50% of the ZP thickness was removed in the thinning group, and a hole 40 μm in diameter was made in the drilling group. Results: A total of 171 in vitro fertilization/intracytoplasmic sperm injection FET cycles, including 85 cycles with drilling LAH and 86 cycles with thinning LAH, were carried out. The thinning group had a similar β-human chorionic gonadotropin-positive rate (38.4% vs. 29.4%), implantation rate (16.5% vs. 14.4%), clinical pregnancy rate (36.0% vs. 25.9%), miscarriage rate (5.8% vs. 2.4%), ongoing pregnancy rate (30.2% vs. 23.5%), and multiple pregnancy rate (7.0% vs. 10.6%) to the drilling LAH group. There were no significant differences in pregnancy outcomes between subgroups defined based on age (older or younger than 35 years) or ZP thickness (greater or less than 17 μm) according to the LAH method. Conclusion: The present study demonstrated that partial ZP thinning or drilling resulted in similar outcomes in implantation and pregnancy rates using thawed embryos, irrespective of women's age or ZP thickness. © 2018. The Korean Society for Reproductive Medicine.Peer reviewe

    Efficient and precise CRISPR/Cas9-mediated MECP2 modifications in human-induced pluripotent stem cells

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    Patients with Rett syndrome (RTT) have severe mental and physical disabilities. The majority of RTT patients carry a heterozygous mutation in methyl-CpG binding protein 2 (MECP2), an X-linked gene encoding an epigenetic factor crucial for normal nerve cell function. No curative therapy for RTT syndrome exists, and cellular mechanisms are incompletely understood. Here, we developed a CRISPR/Cas9-mediated system that targets and corrects the disease relevant regions of the MECP2 exon 4 coding sequence. We achieved homologous recombination (HR) efficiencies of 20% to 30% in human cell lines and iPSCs. Furthermore, we successfully introduced a MECP2(R270X) mutation into the MECP2 gene in human induced pluripotent stem cells (iPSCs). Consequently, using CRISPR/Cas9, we were able to repair such mutations with high efficiency in human mutant iPSCs. In summary, we provide a new strategy for MECP2 gene targeting that can be potentially translated into gene therapy or for iPSCs-based disease modeling of RTT syndrome

    Factors influencing farmers' forestland-use changes over 15 years (2005–2020) in Thua Thien Hue province, Vietnam

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    Over the last decades, Vietnam has seen substantial shifts in forest landscape uses and associated livelihoods. We document the livelihood transformations in Nam Dong, a mountainous district of Central Vietnam, where land uses have changed from the utilisation of products from natural forests and shifting cultivation (swidden agriculture) to acacia tree-dominated plantation forestry. Forestry policies (forestland allocation, plantation development agendas), the increase in the economic value of acacia, and household livelihood assets are the primary factors driving these changes. We also found that there are differences in the access to and ownership of forestland with regard to households of different communities and between poor vs wealthy households. Therefore, careful attention needs to be paid to guide future land use policies in the area to foster social and ecological sustainability. HIGHLIGHTS • Major livelihood and forestland-use changes have taken place in central Vietnam over the last two decades. • There has been widespread conversion of forestland (degraded natural forests, swidden land) and cropland to acacia plantations. • Household-scale forestland use changes were primarily driven by forestry policies, the market for woodchips, and land resource access. • There is inequality in access to and ownership of forestland between poor and wealthier households in the mountain district of Vietnam. • Cases of illegal forestland conversions pose challenges to ensuring sustainable forest landscapes

    Application of Bounded Linear Stability Analysis Method for Metrics-Driven Adaptive Control

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    This paper presents the application of Bounded Linear Stability Analysis (BLSA) method for metrics-driven adaptive control. The bounded linear stability analysis method is used for analyzing stability of adaptive control models, without linearizing the adaptive laws. Metrics-driven adaptive control introduces a notion that adaptation should be driven by some stability metrics to achieve robustness. By the application of bounded linear stability analysis method the adaptive gain is adjusted during the adaptation in order to meet certain phase margin requirements. Analysis of metrics-driven adaptive control is evaluated for a second order system that represents a pitch attitude control of a generic transport aircraft. The analysis shows that the system with the metrics-conforming variable adaptive gain becomes more robust to unmodeled dynamics or time delay. The effect of analysis time-window for BLSA is also evaluated in order to meet the stability margin criteria

    Digital transient torque measurement for rotating or linear AC machines (real time measurement)

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    The digital transient torque measuring device presented in this paper is able to make a "real time" calculation in steady-state and transient conditions of the electromagnetic torque or force of an extremely wide range of ac electrical machines supplied with sinusoidal voltages or through frequency converters with frequencies up to 30 kHz. The device needs no shaft position or speed sensors, it uses exclusively the acquisition of the stator currents and voltages. The main fields of applications are: test shop, control, measurement, integration in a control or regulation unit, element of a monitoring system

    Blockade of SARS-CoV-2 Spike Protein-Mediated Cell–Cell Fusion Using COVID-19 Convalescent Plasma

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    The recent COVID-19 pandemic poses a serious threat to global public health, thus there is an urgent need to define the molecular mechanisms involved in SARS-CoV-2 spike (S) protein-mediated virus entry that is essential for preventing and/or treating this emerging infectious disease. In this study, we examined the blocking activity of human COVID-19 convalescent plasma by cell–cell fusion assays using SARS-CoV-2-S-transfected 293 T as effector cells and ACE2-expressing 293 T as target cells. We demonstrate that the SARS-CoV-2 S protein exhibits a very high capacity for membrane fusion and is efficient in mediating virus fusion and entry into target cells. Importantly, we find that COVID-19 convalescent plasma with high titers of IgG neutralizing antibodies can block cell–cell fusion and virus entry by interfering with the SARS-CoV-2-S/ACE2 or SARS-CoV-S/ACE2 interactions. These findings suggest that COVID-19 convalescent plasma may not only inhibit SARS-CoV-2-S but also cross-neutralize SARS-CoV-S-mediated membrane fusion and virus entry, supporting its potential as a preventive and/or therapeutic agent against SARS-CoV-2 as well as other SARS-CoV infections

    Assisting Vietnamese Mango Farmers to Capture Greater Benefi ts through Improved Supply Chain Management

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    In the developing countries, traditional supply chains for fresh produce are giving way to new supermarket-led supply chains. The rapid transformation in the fruit and vegetable sector is due to the meteoric rise of supermarkets, hypermarkets, superstores, neighbourhood stores, convenience stores, and discount stores, which are impacting on smallholder farmers. This change is also impacting on both upstream and downstream market intermediaries through the demand for safe, high-quality produce that has been produced in a sustainable manner. Problems with procurement in traditional supply chains include few product standards, inconsistent supply, highly variable transaction costs, and limited market information. Supermarkets are now setting new procurement practices and supply systems which focus on reducing costs and improving quality to enable them to sell at lower prices. This will allow them to win over consumers and to obtain a larger market share. However, the ability of smallholder farmers, collector agents, and wholesalers in the Mekong Delta to meet safe food levels and the quality demands of domestic and overseas supermarkets can only be obtained through improving their production and supply chain practices. The implementation of new production and postharvest practices and the modernization of these supply chains may preclude many smallholder farmers from participating. Smallholder farmers must develop risk minimization strategies, such as forming collaborative marketing groups, implementing new crop management and production systems, improving the packaging, and creating more efficient transport methods and handling practices to provide a safe, competitively priced, high-quality product. Understanding the supply chain and where to intervene are essential if farmers and all supply chain participants are to benefit. In this paper, we describe mango supply chains in the Mekong Delta, provide empirical data collected from surveys, and highlight improvements smallholder farmers have been making to achieve greater benefits

    Rainfall variability and internal migration: the importance of agriculture linkage and gender inequality

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    This paper investigates the extent to which exposure to climate volatility can in-fluence individual migration decisions in Vietnam, based on the historical rainfall data from 70 weather stations in Vietnam and the Vietnam Access to Resources House-hold Survey. Utilizing the exogenous variation in the rainfall deviation from the local norms within an individual fixed-effects framework, we uncover the negative associa-tion between rainfall and the probability of individual migration. Individual migration probability drops by 7.5 percentage points when the amount of rainfall relative to the long-run local average doubles. This reduction could potentially be driven by individ-uals who work in the agricultural sector and are less likely to migrate as more rainfall could increase their agricultural incomes. Furthermore, our heterogeneity analyses sug-gest that rainfall shocks could perpetuate gender inequality in Vietnam since women cannot cope with climatic shocks through migration. Policy-makers could shift their focus on flood control and water management in affected areas, where people’s liveli-hoods depend on agriculture, to efficiently address issues related to climate-induced internal migration
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