Influence of Vibrotactile Feedback on Controlling Tilt Motion After Spaceflight

We hypothesize that adaptive changes in how inertial cues from the vestibular system are integrated with other sensory information leads to perceptual disturbances and impaired manual control following transitions between gravity environments. The primary goals of this ongoing post-flight investigation are to quantify decrements in manual control of tilt motion following short-duration spaceflight and to evaluate vibrotactile feedback of tilt as a sensorimotor countermeasure. METHODS. Data is currently being collected on 9 astronaut subjects during 3 preflight sessions and during the first 8 days after Shuttle landings. Variable radius centrifugation (216 deg/s, 30% based on the gain or the amount of tilt disturbance successfully nulled. Manual control performance tended to return to baseline levels within 1-2 days following landing. Root-mean-square position error and tilt velocity were significantly reduced with vibrotactile feedback. CONCLUSIONS. These preliminary results are consistent with our hypothesis that adaptive changes in vestibular processing corresponds to reduced manual control performance following G-transitions. A simple vibrotactile prosthesis improves the ability to null out tilt motion within a limited range of motion disturbances

Electron effective mass in Sn-doped monoclinic single crystal β\beta-gallium oxide determined by mid-infrared optical Hall effect

The isotropic average conduction band minimum electron effective mass in Sn-doped monoclinic single crystal $\beta$-Ga$_2$O$_3$ is experimentally determined by mid-infrared optical Hall effect to be $(0.284\pm0.013)m_{0}$ combining investigations on ($010$) and ($\bar{2}01$) surface cuts. This result falls within the broad range of values predicted by theoretical calculations for undoped $\beta$-Ga$_2$O$_3$. The result is also comparable to recent density functional calculations using the Gaussian-attenuation-Perdue-Burke-Ernzerhof hybrid density functional, which predict an average effective mass of $0.267m_{0}$ (arXiv:1704.06711 [cond-mat.mtrl-sci]). Within our uncertainty limits we detect no anisotropy for the electron effective mass, which is consistent with most previous theoretical calculations. We discuss upper limits for possible anisotropy of the electron effective mass parameter from our experimental uncertainty limits, and we compare our findings with recent theoretical results

Use of polimerase chain reaction for sexing south american camelids

Se reporta el desarrollo y optimizaciones de técnicas moleculares (PCR simple, múltiple y semi-anidada) para determinar el sexo de camélidos sudamericanos (CSA) amplificando la secuencia del gen Zinc Finger Protein (ZF). La técnica utilizó ADN obtenido de 28 muestras de sangre de alpacas, llamas y vicuñas, 20 muestras de heces de vicuñas y guanacos conservadas en etanol al 96%, y 22 embriones de alpaca colectados entre 72 y 96 horas postmonta y preservados en etanol. Las muestras de ADN de sangre y heces fueron extraídas usando kits comerciales, y las de embriones aplicando tres métodos (ebullición, proteinasa K y fenol-cloroformo). Una vez optimizada la PCR simple para la detección de los genes ZFY y ZFX, se implementó la PCR múltiple para ADN de sangre y heces y la PCR semi-anidada para ADN de embriones. La técnica de PCR múltiple determinó el sexo correctamente en el 100% de las muestras de ADN sanguíneo, en el 87.5% de muestras de ADN de heces colectadas en 2008 y en el 50% de las muestras de ADN de heces colectadas en 2004 y preservadas durante cuatro años antes del análisis. La prueba de PCR semi-anidada, sin embargo, no pudo ser optimizada.The objective of this study was to develop a PCR technique to determine the sex of South American camelids (CSA) using Zinc Finger Protein (ZF) sequences from blood and fecal samples, as well as cells from alpaca embryos. A total of 28 alpaca, llama and vicuña blood samples, 20 vicuña and guanaco fecal samples, and 22 alpaca embryos collected between 72 and 96 hours postcopula were used. The fecal and embryo samples were preserved in 96% and 70% ethanol respectively. DNA was extracted from blood and feces using commercial kits. Three methods (boiling, proteinase K and phenol-cloroform) were used to extract DNA from alpaca embryos. Two PCR techniques were developed to analyze DNA: multiplex (for fecal and blood sample DNA) and heminested PCR (for embryo cell DNA). The multiplex PCR accurately determined the sex in 100% of the DNA samples extracted from blood, in 87.5% of the samples extracted from fresh feces and in 50% of the 4-year old fecal samples. The heminested PCR, however, could not be optimized

Anisotropy, Phonon Modes, and Free Charge Carrier Parameters in Monoclinic β-Gallium Oxide Single Crystals

We derive a dielectric function tensor model approach to render the optical response of monoclinic and triclinic symmetry materials with multiple uncoupled infrared and far-infrared active modes. We apply our model approach to monoclinic β-Ga2O3 single-crystal samples. Surfaces cut under different angles from a bulk crystal, (010) and (2̅01), are investigated by generalized spectroscopic ellipsometry within infrared and far-infrared spectral regions. We determine the frequency dependence of 4 independent β-Ga2O3 Cartesian dielectric function tensor elements by matching large sets of experimental data using a point-by-point data inversion approach. From matching our monoclinic model to the obtained 4 dielectric function tensor components, we determine all infrared and far-infrared active transverse optic phonon modes with Au and Bu symmetry, and their eigenvectors within the monoclinic lattice. We find excellent agreement between our model results and results of density functional theory calculations. We derive and discuss the frequencies of longitudinal optical phonons in β-Ga2O3. We derive and report density and anisotropic mobility parameters of the free charge carriers within the tin-doped crystals. We discuss the occurrence of longitudinal phonon plasmon coupled modes in β-Ga2O3 and provide their frequencies and eigenvectors. We also discuss and present monoclinic dielectric constants for static electric fields and frequencies above the reststrahlen range, and we provide a generalization of the Lyddane-Sachs-Teller relation for monoclinic lattices with infrared and far-infrared active modes.We find that the generalized Lyddane-Sachs-Teller relation is fulfilled excellently for β-Ga2O3

Longitudinal Research on Aging Drivers (LongROAD): study design and methods

Background: As an important indicator of mobility, driving confers a host of social and health benefits to older adults. Despite the importance of safe mobility as the population ages, longitudinal data are lacking about the natural history and determinants of driving safety in older adults. Methods: The Longitudinal Research on Aging Drivers (LongROAD) project is a multisite prospective cohort study designed to generate empirical data for understanding the role of medical, behavioral, environmental and technological factors in driving safety during the process of aging. Results: A total of 2990 active drivers aged 65–79 years at baseline have been recruited through primary care clinics or health care systems in five study sites located in California, Colorado, Maryland, Michigan, and New York. Consented participants were assessed at baseline with standardized research protocols and instruments, including vehicle inspection, functional performance tests, and “brown-bag review” of medications. The primary vehicle of each participant was instrumented with a small data collection device that records detailed driving data whenever the vehicle is operating and detects when a participant is driving. Annual follow-up is being conducted for up to three years with a telephone questionnaire at 12 and 36 months and in-person assessment at 24 months. Medical records are reviewed annually to collect information on clinical diagnoses and healthcare utilization. Driving records, including crashes and violations, are collected annually from state motor vehicle departments. Pilot testing was conducted on 56 volunteers during March–May 2015. Recruitment and enrollment were completed between July 2015 and March 2017. Conclusions: Results of the LongROAD project will generate much-needed evidence for formulating public policy and developing intervention programs to maintain safe mobility while ensuring well-being for older adults

The Drosophila homolog of the mammalian imprint regulator, CTCF, maintains the maternal genomic imprint in Drosophila melanogaster

<p>Abstract</p> <p>Background</p> <p>CTCF is a versatile zinc finger DNA-binding protein that functions as a highly conserved epigenetic transcriptional regulator. CTCF is known to act as a chromosomal insulator, bind promoter regions, and facilitate long-range chromatin interactions. In mammals, CTCF is active in the regulatory regions of some genes that exhibit genomic imprinting, acting as insulator on only one parental allele to facilitate parent-specific expression. In <it>Drosophila</it>, CTCF acts as a chromatin insulator and is thought to be actively involved in the global organization of the genome.</p> <p>Results</p> <p>To determine whether CTCF regulates imprinting in <it>Drosophila</it>, we generated <it>CTCF </it>mutant alleles and assayed gene expression from the imprinted <it>Dp(1;f)LJ9 </it>mini-X chromosome in the presence of reduced <it>CTCF </it>expression. We observed disruption of the maternal imprint when <it>CTCF </it>levels were reduced, but no effect was observed on the paternal imprint. The effect was restricted to maintenance of the imprint and was specific for the <it>Dp(1;f)LJ9 </it>mini-X chromosome.</p> <p>Conclusions</p> <p>CTCF in <it>Drosophila </it>functions in maintaining parent-specific expression from an imprinted domain as it does in mammals. We propose that <it>Drosophila </it>CTCF maintains an insulator boundary on the maternal X chromosome, shielding genes from the imprint-induced silencing that occurs on the paternally inherited X chromosome.</p> <p>See commentary: <url>http://www.biomedcentral.com/1741-7007/8/104</url></p

Virulence and Pathogen Multiplication: A Serial Passage Experiment in the Hypervirulent Bacterial Insect-Pathogen Xenorhabdus nematophila

The trade-off hypothesis proposes that the evolution of pathogens' virulence is shaped by a link between virulence and contagiousness. This link is often assumed to come from the fact that pathogens are contagious only if they can reach high parasitic load in the infected host. In this paper we present an experimental test of the hypothesis that selection on fast replication can affect virulence. In a serial passage experiment, we selected 80 lines of the bacterial insect-pathogen Xenorhabdus nematophila to multiply fast in an artificial culture medium. This selection resulted in shortened lag phase in our selected bacteria. We then injected these bacteria into insects and observed an increase in virulence. This could be taken as a sign that virulence in Xenorhabdus is linked to fast multiplication. But we found, among the selected lineages, either no link or a positive correlation between lag duration and virulence: the most virulent bacteria were the last to start multiplying. We then surveyed phenotypes that are under the control of the flhDC super regulon, which has been shown to be involved in Xenorhabdus virulence. We found that, in one treatment, the flhDC regulon has evolved rapidly, but that the changes we observed were not connected to virulence. All together, these results indicate that virulence is, in Xenorhabdus as in many other pathogens, a multifactorial trait. Being able to grow fast is one way to be virulent. But other ways exist which renders the evolution of virulence hard to predict

Lateral Transfer of a Lectin-Like Antifreeze Protein Gene in Fishes

Fishes living in icy seawater are usually protected from freezing by endogenous antifreeze proteins (AFPs) that bind to ice crystals and stop them from growing. The scattered distribution of five highly diverse AFP types across phylogenetically disparate fish species is puzzling. The appearance of radically different AFPs in closely related species has been attributed to the rapid, independent evolution of these proteins in response to natural selection caused by sea level glaciations within the last 20 million years. In at least one instance the same type of simple repetitive AFP has independently originated in two distant species by convergent evolution. But, the isolated occurrence of three very similar type II AFPs in three distantly related species (herring, smelt and sea raven) cannot be explained by this mechanism. These globular, lectin-like AFPs have a unique disulfide-bonding pattern, and share up to 85% identity in their amino acid sequences, with regions of even higher identity in their genes. A thorough search of current databases failed to find a homolog in any other species with greater than 40% amino acid sequence identity. Consistent with this result, genomic Southern blots showed the lectin-like AFP gene was absent from all other fish species tested. The remarkable conservation of both intron and exon sequences, the lack of correlation between evolutionary distance and mutation rate, and the pattern of silent vs non-silent codon changes make it unlikely that the gene for this AFP pre-existed but was lost from most branches of the teleost radiation. We propose instead that lateral gene transfer has resulted in the occurrence of the type II AFPs in herring, smelt and sea raven and allowed these species to survive in an otherwise lethal niche

Prevalence of Potentially Inappropriate Medication use in older drivers

Background Potentially Inappropriate Medication (PIM) use has been studied in a variety of older adult populations across the world. We sought to examine the prevalence and correlates of PIM use in older drivers. Methods We applied the American Geriatrics Society 2015 Beers Criteria to baseline data collected from the “brown-bag” review of medications for participants of the Longitudinal Research on Aging Drivers (LongROAD) study to examine the prevalence and correlates of PIM use in a geographically diverse, community-dwelling sample of older drivers (n = 2949). Proportions of participants who used one or more PIMs according to the American Geriatrics Society 2015 Beers Criteria, and estimated odds ratios (ORs) and 95% confidence intervals (CIs) of PIM use associated with participant characteristics were calculated. Results Overall, 18.5% of the older drivers studied used one or more PIM. The most commonly used therapeutic category of PIM was benzodiazepines (accounting for 16.6% of the total PIMs identified), followed by nonbenzodiazepine hypnotics (15.2%), antidepressants (15.2%), and first-generation antihistamines (10.5%). Compared to older drivers on four or fewer medications, the adjusted ORs of PIM use were 2.43 (95% CI 1.68–3.51) for those on 5–7 medications, 4.19 (95% CI 2.95–5.93) for those on 8–11 medications, and 8.01 (95% CI 5.71–11.23) for those on ≥12 medications. Older drivers who were female, white, or living in urban areas were at significantly heightened risk of PIM use. Conclusion About one in five older drivers uses PIMs. Commonly used PIMs are medications known to impair driving ability and increase crash risk. Implementation of evidence-based interventions to reduce PIM use in older drivers may confer both health and safety benefits. Trial registration Not applicable