611 research outputs found

    The Impact of Inappropriate Gestational Weight Gain on Pregnancy, Delivery, and Neonatal Outcomes

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    Inappropriate weight gain during pregnancy is a widespread problem associated with adverse maternal and newborn outcomes. This studyā€™s objective was to examine the impact of gestational weight gain (GWG) above and below the Institute of Medicine (IOM) guidelines on pregnancy, delivery, and newborn outcomes in a rural population. Women were recruited at the first prenatal visit, and data was collected through research interviews and examination of prenatal and delivery medical records. Prepregnancy weight and weight at delivery were obtained, and the final sample (n=913) was restricted to women with singleton pregnancies. Participants were categorized by prepregnancy body mass index (BMI) and GWG above, within, or below IOM guidelines based on gestational length. After controlling for pregnancy smoking, odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to identify significant outcomes associated with high or low weight gain, with normal GWG as the control. Of the 913 participants, 208 (22.8%) had inadequate GWG, 255 (27.9%) gained within the recommended range, and 450 (49.3%) gained more than recommended. Inadequate GWG was associated with delivery before 39 weeks, oxygen administration to the infant, admission to the neonatal intensive care unit (NICU), and a hospital stay longer than seven days. Excess GWG was associated with preeclampsia, pregnancy-induced hypertension (PIH), gestational diabetes mellitus, cesarean delivery, labor longer than 12 hours, macrosomia, and large-for-gestational-age (LGA) infants. GWG outside IOM guidelines was prevalent in the sample and associated with numerous adverse outcomes, suggesting a need for increased awareness and improved management of GWG in this population

    Structural and petrologic insights into the emplacement of effusive silicic lavas: Inyo Domes, California

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    The Long Valley volcanic region, eastern California, USA is most famous for the caldera-forming eruption which produced the Bishop Tuff ~760,000 years ago. Over the last 3,000 years volcanism has been focused in the western margin of the region through punctuated eruptions of silicic lavas and domes. Three simultaneous effusive silicic eruptions, ~600 years ago, generated three lava domes: Obsidian Dome; Glass Creek Dome; and Deadman Dome which erupted onto vastly different topographies. These domes are exceptionally unique as they erupted variable amounts of two textural and chemical endmember lavas (crystal-rich and crystal-poor) that intimately mixed. The overarching goal of this dissertation is to investigate the magmatic genesis and emplacement styles of these young effusive silicic lava domes. The first chapter of this dissertation investigates the petrogenesis of the three 600-year-old Inyo Domes, concluding they originated from variable mixing of several long-lived, complex, contiguous, magmatic plumbing systems. The second chapter characterizes brittle and brittle-ductile structures preserved across the upper surface of Obsidian Dome, challenging the long-standing theory that the upper surface of silicic lavas is dominated by ductile folding. The third chapter utilizes morphologies classified from analog modeling to characterize the upper surface of Obsidian Dome and Glass Creek Dome to assess the control of underlying topography and crystallinity on lava emplacement rates. The first chapter of this dissertation investigates the petrogenesis of the three 600-year-old Inyo Domes, concluding they originated from variable mixing of several long-lived, complex, contiguous, magmatic plumbing systems. The second chapter characterizes brittle and brittle-ductile structures preserved across the upper surface of Obsidian Dome, challenging the long-standing theory that the upper surface of silicic lavas is dominated by ductile folding. The third chapter utilizes morphologies classified from analog modeling to characterize the upper surface of Obsidian Dome and Glass Creek Dome to assess the control of underlying topography and crystallinity on lava emplacement rates

    Colloquium 9: Structural and Molecular Dissection of the Node of Ranvier

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65182/1/j.1471-4159.81.s1.94.x.pd

    Na+ Channel Ī² Subunits: Overachievers of the Ion Channel Family

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    Voltage-gated Na+ channels (VGSCs) in mammals contain a pore-forming Ī± subunit and one or more Ī² subunits. There are five mammalian Ī² subunits in total: Ī²1, Ī²1B, Ī²2, Ī²3, and Ī²4, encoded by four genes: SCN1Bā€“SCN4B. With the exception of the SCN1B splice variant, Ī²1B, the Ī² subunits are type I topology transmembrane proteins. In contrast, Ī²1B lacks a transmembrane domain and is a secreted protein. A growing body of work shows that VGSC Ī² subunits are multifunctional. While they do not form the ion channel pore, Ī² subunits alter gating, voltage-dependence, and kinetics of VGSCĪ± subunits and thus regulate cellular excitability in vivo. In addition to their roles in channel modulation, Ī² subunits are members of the immunoglobulin superfamily of cell adhesion molecules and regulate cell adhesion and migration. Ī² subunits are also substrates for sequential proteolytic cleavage by secretases. An example of the multifunctional nature of Ī² subunits is Ī²1, encoded by SCN1B, that plays a critical role in neuronal migration and pathfinding during brain development, and whose function is dependent on Na+ current and Ī³-secretase activity. Functional deletion of SCN1B results in Dravet Syndrome, a severe and intractable pediatric epileptic encephalopathy. Ī² subunits are emerging as key players in a wide variety of physiopathologies, including epilepsy, cardiac arrhythmia, multiple sclerosis, Huntingtonā€™s disease, neuropsychiatric disorders, neuropathic and inflammatory pain, and cancer. Ī² subunits mediate multiple signaling pathways on different timescales, regulating electrical excitability, adhesion, migration, pathfinding, and transcription. Importantly, some Ī² subunit functions may operate independently of Ī± subunits. Thus, Ī² subunits perform critical roles during development and disease. As such, they may prove useful in disease diagnosis and therapy

    Helical Magnetorotational Instability in Magnetized Taylor-Couette Flow

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    Hollerbach and Rudiger have reported a new type of magnetorotational instability (MRI) in magnetized Taylor-Couette flow in the presence of combined axial and azimuthal magnetic fields. The salient advantage of this "helical'' MRI (HMRI) is that marginal instability occurs at arbitrarily low magnetic Reynolds and Lundquist numbers, suggesting that HMRI might be easier to realize than standard MRI (axial field only). We confirm their results, calculate HMRI growth rates, and show that in the resistive limit, HMRI is a weakly destabilized inertial oscillation propagating in a unique direction along the axis. But we report other features of HMRI that make it less attractive for experiments and for resistive astrophysical disks. Growth rates are small and require large axial currents. More fundamentally, instability of highly resistive flow is peculiar to infinitely long or periodic cylinders: finite cylinders with insulating endcaps are shown to be stable in this limit. Also, keplerian rotation profiles are stable in the resistive limit regardless of axial boundary conditions. Nevertheless, the addition of toroidal field lowers thresholds for instability even in finite cylinders.Comment: 16 pages, 2 figures, 1 table, submitted to PR

    Biobased Sprayable Mulch Films Suppressed Annual Weeds in Vegetable Crops

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    Biobased sprayable mulch (BSM) films are a potential alternative to herbicides, polyethylene plastic mulch film, and hand weeding for specialty crops. We developed a series of BSM films using locally available biomaterials [including corn (Zea mays) starch, glycerol, keratin hydrolysate, corn gluten meal, corn zein, eggshells, and isolated soy (Glycine max) protein] and tested their effects on weeds and crop yield during a total of seven greenhouse or field trials between 2017 and 2019 in Nebraska, USA. Application rates of BSM films applied in pots (greenhouse), planting holes in plastic film (field), or bed tops (field) ranged from 0.9 to 18.2 Lā€¢m-2 ; they were applied before and after the emergence of weeds. Weed control efficacy was variable, and results of greenhouse pots were rarely replicated under field conditions. Increasing the viscosity of the final suspension tested [BSM7; a mix of corn starch (72.8 gā€¢L-1 ), glycerol (184.7 mLā€¢L-1 ), keratin hydrolysate (733.3 mLā€¢L-1 ), corn zein (19.8 gā€¢L-1 ), and isolated soy protein (19.8 gā€¢L-1 )] reduced weed biomass by more than 96% in field-grown kale (Brassica oleracea var. sabellica) when applied to bare soil bed tops before or after weed emergence, but kale yield in treated plots was not different from the weedy control. The results demonstrated the potential for postemergence applications of BSM films, which increase application timing flexibility for growers. Further research is needed to explore the effects of BSM films on soil properties and crop physiology and yield

    Modulation of the effects of class Ib antiarrhythmics on cardiac NaV1.5-encoded channels by accessory NaVĪ² subunits

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    Native myocardial voltage-gated sodium (NaV) channels function in macromolecular complexes comprising a pore-forming (Ī±) subunit and multiple accessory proteins. Here, we investigated the impact of accessory NaVĪ²1 and NaVĪ²3 subunits on the functional effects of 2 well-known class Ib antiarrhythmics, lidocaine and ranolazine, on the predominant NaV channel Ī± subunit, NaV1.5, expressed in the mammalian heart. We showed that both drugs stabilized the activated conformation of the voltage sensor of domain-III (DIII-VSD) in NaV1.5. In the presence of NaVĪ²1, the effect of lidocaine on the DIII-VSD was enhanced, whereas the effect of ranolazine was abolished. Mutating the main class Ib drug-binding site, F1760, affected but did not abolish the modulation of drug block by NaVĪ²1/Ī²3. Recordings from adult mouse ventricular myocytes demonstrated that loss of Scn1b (NaVĪ²1) differentially affected the potencies of lidocaine and ranolazine. In vivo experiments revealed distinct ECG responses to i.p. injection of ranolazine or lidocaine in WT and Scn1b-null animals, suggesting that NaVĪ²1 modulated drug responses at the whole-heart level. In the human heart, we found that SCN1B transcript expression was 3 times higher in the atria than ventricles, differences that could, in combination with inherited or acquired cardiovascular disease, dramatically affect patient response to class Ib antiarrhythmic therapies

    Cloning and expression of a zebrafish SCN1B ortholog and identification of a species-specific splice variant

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    Abstract Background Voltage-gated Na+ channel Ī²1 (Scn1b) subunits are multi-functional proteins that play roles in current modulation, channel cell surface expression, cell adhesion, cell migration, and neurite outgrowth. We have shown previously that Ī²1 modulates electrical excitability in vivo using a mouse model. Scn1b null mice exhibit spontaneous seizures and ataxia, slowed action potential conduction, decreased numbers of nodes of Ranvier in myelinated axons, alterations in nodal architecture, and differences in Na+ channel Ī± subunit localization. The early death of these mice at postnatal day 19, however, make them a challenging model system to study. As a first step toward development of an alternative model to investigate the physiological roles of Ī²1 subunits in vivo we cloned two Ī²1-like subunit cDNAs from D. rerio. Results Two Ī²1-like subunit mRNAs from zebrafish, scn1ba_tv1 and scn1ba_tv2, arise from alternative splicing of scn1ba. The deduced amino acid sequences of Scn1ba_tv1 and Scn1ba_tv2 are identical except for their C-terminal domains. The C-terminus of Scn1ba_tv1 contains a tyrosine residue similar to that found to be critical for ankyrin association and Na+ channel modulation in mammalian Ī²1. In contrast, Scn1ba_tv2 contains a unique, species-specific C-terminal domain that does not contain a tyrosine. Immunohistochemical analysis shows that, while the expression patterns of Scn1ba_tv1 and Scn1ba_tv2 overlap in some areas of the brain, retina, spinal cord, and skeletal muscle, only Scn1ba_tv1 is expressed in optic nerve where its staining pattern suggests nodal expression. Both scn1ba splice forms modulate Na+ currents expressed by zebrafish scn8aa, resulting in shifts in channel gating mode, increased current amplitude, negative shifts in the voltage dependence of current activation and inactivation, and increases in the rate of recovery from inactivation, similar to the function of mammalian Ī²1 subunits. In contrast to mammalian Ī²1, however, neither zebrafish subunit produces a complete shift to the fast gating mode and neither subunit produces complete channel inactivation or recovery from inactivation. Conclusion These data add to our understanding of structure-function relationships in Na+ channel Ī²1 subunits and establish zebrafish as an ideal system in which to determine the contribution of scn1ba to electrical excitability in vivo.http://deepblue.lib.umich.edu/bitstream/2027.42/112585/1/12864_2007_Article_939.pd

    Teaching with Digital 3D Models of Minerals and Rocks

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    The disruption to geoscience curricula due to the COVID-19 pandemic highlights the difficulty of making mineral and rock samples accessible to students online rather than through traditional lab classes. In spring 2020, our community had to adapt rapidly to remote instruction; this transition amplified existing disparities in access to geoscience education but can be a catalyst to increase accessibility and flexibility in instruction permanently. Fortunately, a rich collection of 3D mineral and rock samples is being generated by a community of digital modelers (e.g., Perkins et al., 2019)
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