Author
Raymond M. Anchan
Other affiliations: University of North Carolina at Chapel Hill, East Carolina University, Harvard University ...read more
Bio: Raymond M. Anchan is an academic researcher from Brigham and Women's Hospital. The author has contributed to research in topics: Uterine fibroids & Hysterectomy. The author has an hindex of 18, co-authored 56 publications receiving 1275 citations. Previous affiliations of Raymond M. Anchan include University of North Carolina at Chapel Hill & East Carolina University.
Papers published on a yearly basis
Papers
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TL;DR: This work explains theoretically and observe experimentally a threshold droplet radius during the vitrification of a cryoprotectant droplet in the presence of the Leidenfrost effect.
Abstract: The vitrification of a liquid occurs when ice crystal formation is prevented in the cryogenic environment through ultrarapid cooling. In general, vitrification entails a large temperature difference between the liquid and its surrounding medium. In our droplet vitrification experiments, we observed that such vitrification events are accompanied by a Leidenfrost phenomenon, which impedes the heat transfer to cool the liquid, when the liquid droplet comes into direct contact with liquid nitrogen. This is distinct from the more generally observed Leidenfrost phenomenon that occurs when a liquid droplet is self-vaporized on a hot plate. In the case of rapid cooling, the phase transition from liquid to vitrified solid (i.e., vitrification) and the levitation of droplets on liquid nitrogen (i.e., Leidenfrost phenomenon) take place simultaneously. Here, we investigate these two simultaneous physical events by using a theoretical model containing three dimensionless parameters (i.e., Stefan, Biot, and Fourier numbers). We explain theoretically and observe experimentally a threshold droplet radius during the vitrification of a cryoprotectant droplet in the presence of the Leidenfrost effect.
126 citations
TL;DR: It is suggested that local retinoid signaling is essential for the normal development of the mammalian olfactory pathway.
Abstract: We have evaluated the role of retinoid signaling in the early development of the olfactory epithelium and olfactory bulb. When retinoid-mediated gene expression is blocked briefly in mouse embryos at midgestation with citral (a general alcohol dehydrogenase antagonist that is thought to interfere with retinoid synthesis), the spectrum of morphogenetic abnormalities includes disruption of olfactory pathway development. It is difficult, however, to assess the specificity of this pharmacological manipulation, insofar as it also compromises several other aspects of central nervous system development. In homozygous Pax6 mutant mice (small eye: Pax6Sey-Neu), there is a more discrete lesion to the olfactory pathway: The epithelium and bulb cannot be recognized at any time during development, whereas other forebrain subdivisions can still be recognized. This loss of the entire primary olfactory pathway is accompanied by a failure of retinoid-mediated gene expression limited to the frontonasal region and forebrain. Retinoid receptors are expressed in the forebrain of Pax6Sey-Neu/Pax6Sey-Neu embryos, and the mutant forebrain remains responsive to exogenous retinoic acid. However, in Pax6Sey-Neu/Pax6Sey-Neu embryos, retinoic acid (RA) is not produced by the frontonasal mesenchyme, which normally provides local retinoid signals to the placode and forebrain. Together, these results suggest that local retinoid signaling is essential for the normal development of the mammalian olfactory pathway. J. Comp. Neurol. 379:171–184, 1997. © 1997 Wiley-Liss, Inc.
106 citations
TL;DR: Some recent research in centrifugation and non-centrifugation based techniques and their effect on sperm quality and ART outcomes are discussed.
103 citations
TL;DR: A simple, cost-effective microfluidic channel is designed on the same scale to regulate the sperm's journey to the egg, supported by a computational model incorporating the exhaustion time of sperm.
Abstract: Fertilization is central to the survival and propagation of a species, however, the precise mechanisms that regulate the sperm's journey to the egg are not well understood. In nature, the sperm has to swim through the cervical mucus, akin to a microfluidic channel. Inspired by this, a simple, cost-effective microfluidic channel is designed on the same scale. The experimental results are supported by a computational model incorporating the exhaustion time of sperm.
102 citations
TL;DR: The presented chip is an easy‐to‐use high‐throughput sperm sorter that provides standardized sperm sorting assay with less reliance on operators's skills, facilitating reliable operational steps.
Abstract: Fertilization and reproduction are central to the survival and propagation of a species. Couples who cannot reproduce naturally have to undergo in vitro clinical procedures. An integral part of these clinical procedures includes isolation of healthy sperm from raw semen. Existing sperm sorting methods are not efficient and isolate sperm having high DNA fragmentation and reactive oxygen species (ROS), and suffer from multiple manual steps and variations between operators. Inspired by in vivo natural sperm sorting mechanisms where vaginal mucus becomes less viscous to form microchannels to guide sperm towards egg, a chip is presented that efficiently sorts healthy, motile and morphologically normal sperm without centrifugation. Higher percentage of sorted sperm show significantly lesser ROS and DNA fragmentation than the conventional swim-up method. The presented chip is an easy-to-use high-throughput sperm sorter that provides standardized sperm sorting assay with less reliance on operators's skills, facilitating reliable operational steps.
97 citations
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TL;DR: The progress of the current state-of-the-art engineering methods to create cell-encapsulating hydrogel tissue constructs as well as their applications in in vitro models in biomedicine are detailed.
723 citations
TL;DR: A comprehensive review that synthesises the highlights of a century of classical experimental research, together with more modern evidence for the tissues and molecules involved in the induction of each placode is provided.
561 citations
TL;DR: Because the clinical deterioration that occurs in schizophrenia may actually begin in the prepsychotic phase, early identification and intervention may favorably alter the course and outcome of schizophrenia.
551 citations
TL;DR: The data suggest that the estrogen-progestin regimen increases breast cancer risk beyond that associated with estrogen alone, and were evident for the majority of invasive tumors with ductal histology and regardless of extent of invasive disease.
Abstract: N A RECENT COLLABORATIVE REanalysis of more than 90% of the world’s epidemiological data on the relationship between menopausal hormone replacement therapy (HRT) and breast cancer risk, it was found that longer durations of recent, but not past, use of HRT increased breast cancer risk, particularly among leaner women and for tumors that were less clinically advanced. 1 Unresolved issues include the extent to which the findings were due to a biological effect of hormones rather than issues of screening and ascertainment. The data were also insufficient to determine whether a combined estrogen-progestin regimen increased risk beyond that associated with estrogen alone. In 1994, we published data on HRT
546 citations