1,120 research outputs found

    Quality Control Factors Influencing the Successful and Reliable Implementation of Oocyte and Embryo Vitrification

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    Clinical vitrification evolved slowly, with interests and acceptance being commercially driven by the development of unique devices, safer solutions, and the misconception that ultra‐rapid cooling in an “open” system was a necessity to optimizing vitrification success. Furthermore, the dogma surrounding the importance of cooling rates has led to unsafe practices subject to excessive technical variation and risky modifications to create closed‐storage devices. The aim of this chapter is to highlight important quality control factors (e.g., ease of use, repeatability, reliability, labeling security, and cryostorage safety) into the selection process of which device/solution to use, independent of commercial manipulations. In addition, we provide clinical and experimental evidence in support of warming rates being the most important factor determining vitrification survival. Lastly, we exhibit indisputable support that aseptic, closed vitrification systems, specifically microSecure vitrification (ÎŒS‐VTF), can achieve success with attention to quality control details often lacking in open vitrification devices

    Show Me the Money!

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    Table of Contents: What Are Expanded Learning Opportunities? Identifying resources available to support expanded learning opportunity programs in Nebraska Some Key Findings of the Fund Mapping Projec

    Electronic structure of the substitutional versus interstitial manganese in GaN

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    Density-functional studies of the electron states in the dilute magnetic semiconductor GaN:Mn reveal major differences for the case of the Mn impurity at the substitutional site Mn_Ga versus the interstitial site Mn_I. The splitting of the two-fold and the three-fold degenerate Mn(d)states in the gap are reversed between the two cases, which is understood in terms of the symmetry-controlled hybridization with the neighboring atoms. In contrast to Mn_Ga, which acts as a deep acceptor, Mn_I acts as a donor, suggesting the formation of Coulomb-stabilized complexes such as (Mn_Ga Mn_I Mn_Ga), where the acceptor level of Mn_Ga is passivated by the Mn_I donor. Formation of such passivated clusters might be the reason for the observed low carrier-doping efficiency of Mn in GaN. Even though the Mn states are located well inside the gap,the wave functions are spread far away from the impurity center. This is caused by the hybridization with the nitrogen atoms, which acquire small magnetic moments aligned with the Mn moment. Implications of the differences in the electronic structure for the optical properties are discussed

    Vitrification: Fundamental Principles and Its Application for Cryopreservation of Human Reproductive Cells

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    The fundamental understanding of cryobiology through experimentation in the 1960s, 1970s, and 1980s has led to the development of today’s vitrification technology. Although human embryo and oocyte vitrification was slow to evolve, it has become an invaluable technology in the field of reproductive medicine. The aim of this chapter is to discuss some of the underlying basic principles behind forming a metastable glass phase during rapid cooling in liquid nitrogen (LN2) and the prevention of recrystallization events upon warming. We then highlight how this understanding has led to its highly effective and reliable usage in clinical IVF. Furthermore, we describe how quality control factors (e.g., ease of use, repeatability, reliability, labeling security, and cryostorage safety) can vary between vitrification device systems, potentially influencing clinical outcomes and creating possible liability issues. An open-minded approach to continued experimentation is a necessity, especially pertaining to oocyte freeze preservation, if we are to optimize the vitrification of reproductive cells and tissue in the future

    Efficient Uncertainty Quantification in a Multiscale Model of Pulmonary Arterial and Venous Hemodynamics

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    Computational hemodynamics models are becoming increasingly useful in the management and prognosis of complex, multiscale pathologies, including those attributed to the development of pulmonary vascular disease. However, diseases like pulmonary hypertension are heterogeneous, and affect both the proximal arteries and veins as well as the microcirculation. Simulation tools and the data used for model calibration are also inherently uncertain, requiring a full analysis of the sensitivity and uncertainty attributed to model inputs and outputs. Thus, this study quantifies model sensitivity and output uncertainty in a multiscale, pulse-wave propagation model of pulmonary hemodynamics. Our pulmonary circuit model consists of fifteen proximal arteries and twelve proximal veins, connected by a two-sided, structured tree model of the distal vasculature. We use polynomial chaos expansions to expedite the sensitivity and uncertainty quantification analyses and provide results for both the proximal and distal vasculature. Our analyses provide uncertainty in blood pressure, flow, and wave propagation phenomenon, as well as wall shear stress and cyclic stretch, both of which are important stimuli for endothelial cell mechanotransduction. We conclude that, while nearly all the parameters in our system have some influence on model predictions, the parameters describing the density of the microvascular beds have the largest effects on all simulated quantities in both the proximal and distal circulation.Comment: 10 Figures, 2 table

    The effect of dimple error on the horizontal launch angle and side spin of the golf ball during putting

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    This study aimed to examine the effect of the impact point on the golf ball on the horizontal launch angle and side spin during putting with a mechanical putting arm and human participants. Putts of 3.2 m were completed with a mechanical putting arm (four putter-ball combinations, total of 160 trials) and human participants (two putter-ball combinations, total of 337 trials). The centre of the dimple pattern (centroid) was located and the following variables were measured: distance and angle of the impact point from the centroid and surface area of the impact zone. Multiple regression analysis was conducted to identify whether impact variables had significant associations with ball roll variables, horizontal launch angle and side spin. Significant associations were identified between impact variables and horizontal launch angle with the mechanical putting arm but this was not replicated with human participants. The variability caused by “dimple error” was minimal with the mechanical putting arm and not evident with human participants. Differences between the mechanical putting arm and human participants may be due to the way impulse is imparted on the ball. Therefore it is concluded that variability of impact point on the golf ball has a minimal effect on putting performanc

    Autologous Platelet-Rich Plasma Infusion to Improve Pregnancy Outcome in Suboptimal Endometrium: A Review

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    Over the past decade, platelet-rich plasma (PRP) has been used in several fields of medicine to promote cell growth and expedite wound healing for the treatment of arthritis, nerve injury, tendinitis, bone regeneration, cardiac muscle repair, and oral & plastic surgery. Recently, researchers have been applying autologous PRP to bolster the growth of endometrial lining in patients with a history of endometrium-related failed embryo transfers. Evidence reveals that PRP is a rich source of active cytokines and various growth factors, which come from an autologous source that can be easily attained from peripheral blood without risk of disease transmission to the patient. In this review, several studies were analyzed that involved patients 18–42 years of age undergoing hormone replacement therapy (HRT) in preparation for embryo transfer and serial transvaginal ultrasound in conjunction with PRP infusions into the endometrium via an intrauterine insemination (IUI) catheter. Exclusion criteria included patients with endometritis, polyps, or adhesions. Embryo transfers (ET) were performed when the endometrial lining achieved a thickness of >7 mm. The database indicates that PRP infusion therapy is a promising low-cost treatment for HRT patients that significantly increases endometrial thickness and improves pregnancy success in a previous suboptimal ET patient population
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