Size tunable visible and near-infrared photoluminescence from vertically etched silicon quantum dots

Corrugated etching techniques were used to fabricate size-tunable silicon quantum dots that luminesce under photoexcitation, tunable over the visible and near infrared. By using the fidelity of lithographic patterning and strain limited, self-terminating oxidation, uniform arrays of pillar containing stacked quantum dots as small as 2 nm were patterned. Furthermore, an array of pillars, with multiple similar sized quantum dots on each pillar, was fabricated and tested. The photoluminescence displayed a multiple, closely peaked emission spectra corresponding to quantum dots with a narrow size distribution. Similar structures can provide quantum confinement effects for future nanophotonic and nanoelectronic devices

Blood-based bioenergetic profiling is related to differences in brain morphology in African Americans with Type 2 diabetes.

Blood-based bioenergetic profiling has promising applications as a minimally invasive biomarker of systemic bioenergetic capacity. In the present study, we examined peripheral blood mononuclear cell (PBMC) mitochondrial function and brain morphology in a cohort of African Americans with long-standing Type 2 diabetes. Key parameters of PBMC respiration were correlated with white matter, gray matter, and total intracranial volumes. Our analyses indicate that these relationships are primarily driven by the relationship of systemic bioenergetic capacity with total intracranial volume, suggesting that systemic differences in mitochondrial function may play a role in overall brain morphology

Visuomotor Entrainment and the Frequency-Dependent Response of Walking Balance to Perturbations

Visuomotor entrainment, or the synchronization of motor responses to visual stimuli, is a naturally emergent phenomenon in human standing. Our purpose was to investigate the prevalence and resolution of visuomotor entrainment in walking and the frequency-dependent response of walking balance to perturbations. We used a virtual reality environment to manipulate optical flow in ten healthy young adults during treadmill walking. A motion capture system recorded trunk, sacrum, and heel marker trajectories during a series of 3-min conditions in which we perturbed a virtual hallway mediolaterally with systematic changes in the driving frequencies of perceived motion. We quantified visuomotor entrainment using spectral analyses and changes in balance control using trunk sway, gait variability, and detrended fluctuation analyses (DFA). ML kinematics were highly sensitive to visual perturbations, and instinctively synchronized (i.e., entrained) to a broad range of driving frequencies of perceived ML motion. However, the influence of visual perturbations on metrics of walking balance was frequency-dependent and governed by their proximity to stride frequency. Specifically, we found that a driving frequency nearest to subjects' average stride frequency uniquely compromised trunk sway, gait variability, and step-to-step correlations. We conclude that visuomotor entrainment is a robust and naturally emerging phenomenon during human walking, involving coordinated and frequency-dependent adjustments in trunk sway and foot placement to maintain balance at the whole-body level. These findings provide mechanistic insight into how the visuomotor control of walking balance is disrupted by visual perturbations and important reference values for the emergence of balance deficits due to age, injury, or disease

Family involvement for children with disruptive behaviors: The role of parenting stress and motivational beliefs

Children with disruptive behaviors are at risk for adverse outcomes. Family involvement is a significant predictor of positive child behavior outcomes; however, little research has investigated parent psychological variables that influence family involvement for children with disruptive behaviors. This study investigated the role of parental motivational beliefs (i.e., role construction and efficacy) as a potential mechanism by which parenting stress impacts family involvement for families of children with disruptive behaviors. Results indicated that parent role construction mediated the relation between parenting stress and all aspects of family involvement examined (i.e., home-based involvement, school-based involvement, and home–school communication). Parent efficacy mediated the relation between parenting stress and home-based involvement only. Parents of children with disruptive behaviors reporting stress may experience negative beliefs about their role and efficacy to support their child’s education, which may thereby negatively influence their actual involvement. Therefore, parent motivational beliefs may serve as an important point for intervention to support involvement of families of children with disruptive behavior

Stem‐cell–based therapies to enhance peripheral nerve regeneration

Peripheral nerve injury remains a major cause of morbidity in trauma patients. Despite advances in microsurgical techniques and improved understanding of nerve regeneration, obtaining satisfactory outcomes after peripheral nerve injury remains a difficult clinical problem. There is a growing body of evidence in preclinical animal studies demonstrating the supportive role of stem cells in peripheral nerve regeneration after injury. The characteristics of both mesoderm‐derived and ectoderm‐derived stem cell types and their role in peripheral nerve regeneration are discussed, specifically focusing on the presentation of both foundational laboratory studies and translational applications. The current state of clinical translation is presented, with an emphasis on both ethical considerations of using stems cells in humans and current governmental regulatory policies. Current advancements in cell‐based therapies represent a promising future with regard to supporting nerve regeneration and achieving significant functional recovery after debilitating nerve injuries.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154610/1/mus26760.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154610/2/mus26760_am.pd

Effects of Normal Aging on Visuo-Motor Plasticity

Normal aging is associated with declines in neurologic function. Uncompensated visual and vestibular problems may have dire consequences including dangerous falls. Visuomotor plasticity is a form of behavioral neural plasticity which is important in the process of adapting to visual or vestibular alteration, including those changes due to pathology, pharmacotherapy, surgery or even entry into a microgravity or underwater environment. In order to determine the effects of aging on visuomotor plasticity, we chose the simple and easily measured paradigm of visual-motor re-arrangement created by using visual displacement prisms while throwing small balls at a target. Subjects threw balls before, during and after wearing a set of prisms which displace the visual scene by twenty degrees to the right. Data obtained during adaptation were modeled using multilevel analyses for 73 subjects aged 20 to 80 years. We found no statistically significant difference in measures of visuomotor plasticity with advancing age. Further studies are underway examining variable practice training as a potential mechanism for enhancing this form of behavioral neural plasticity

Urinary Nâ Telopeptide as Predictor of Onset of Menopauseâ Related Bone Loss in Preâ and Perimenopausal Women

The menopause transition (MT) is a period of rapid bone loss and has been proposed to be a timeâ limited window for early intervention to prevent permanent microarchitectural damage and reduce the risk of subsequent fracture. To intervene early, however, we first need to be able to determine whether menopauseâ related bone loss is about to begin, in advance of substantial bone loss. The objective of this study was, therefore, to assess whether urinary Nâ telopeptide (Uâ NTX) in preâ or early perimenopause can predict the onset of menopauseâ related bone loss. Repeated Uâ NTX measurements were obtained during preâ and early perimenopause in 1243 participants from the Study of Women’s Health Across the Nation (SWAN). We examined the ability of Uâ NTX to predict the onset of significant menopauseâ related bone loss (categorical outcome, yes versus no) at the lumbar spine (LS) and femoral neck (FN), defined as annualized bone mineral density (BMD) decline at a rate faster than the smallest detectable change in BMD over the 3 to 4 years from the time of Uâ NTX measurement. Adjusting for age, race/ethnicity, body mass index, urine collection time, starting BMD, and study site in multivariable, modified Poisson regression, every standard deviation increment in Uâ NTX, measured at baseline in early perimenopausal women, was associated with an 18% and 22% greater risk of significant bone loss at the LS (pâ =â 0.003) and FN (pâ =â 0.003), respectively. The area under the receiverâ operator curve for predicting LS and FN bone loss was 0.72 and 0.72, respectively. In mixedâ effects analysis of all repeated measures of early perimenopausal Uâ NTX over followâ up, Uâ NTX predicted onset of bone loss at the LS (pâ =â 0.002) but not at the FN. We conclude that Uâ NTX can be used early in the MT to determine if a woman is about to experience significant LS bone loss before there has been substantial skeletal deterioration. © 2018 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149249/1/jbm410116_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149249/2/jbm410116.pd

Defining the Risk of Zika and Chikungunya Virus Transmission in Human Population Centers of the Eastern United States

The recent spread of mosquito-transmitted viruses and associated disease to the Americas motivates a new, data-driven evaluation of risk in temperate population centers. Temperate regions are generally expected to pose low risk for significant mosquito-borne disease; however, the spread of the Asian tiger mosquito (Aedes albopictus) across densely populated urban areas has established a new landscape of risk. We use a model informed by field data to assess the conditions likely to facilitate local transmission of chikungunya and Zika viruses from an infected traveler to Ae. albopictus and then to other humans in USA cities with variable human densities and seasonality. Mosquito-borne disease occurs when specific combinations of conditions maximize virus-to-mosquito and mosquito-to-human contact rates. We develop a mathematical model that captures the epidemiology and is informed by current data on vector ecology from urban sites. The model demonstrates that under specific but realistic conditions, fifty-percent of introductions by infectious travelers to a high human, high mosquito density city could initiate local transmission and 10% of the introductions could result in 100 or more people infected. Despite the propensity for Ae. albopictus to bite non-human vertebrates, we also demonstrate that local virus transmission and human outbreaks may occur when vectors feed from humans even just 40% of the time. Inclusion of human behavioral changes and mitigations were not incorporated into the models and would likely reduce predicted infections. This work demonstrates how a conditional series of non-average events can result in local arbovirus transmission and outbreaks of human disease, even in temperate cities

Estradiol and Follicleâ Stimulating Hormone as Predictors of Onset of Menopause Transitionâ Related Bone Loss in Preâ and Perimenopausal Women

The menopause transition (MT) may be an opportunity for early intervention to prevent rapid bone loss. To intervene early, we need to be able to prospectively identify preâ and perimenopausal women who are beginning to lose bone. This study examined whether estradiol (E2), or follicleâ stimulating hormone (FSH), measured in preâ and perimenopausal women, can predict significant bone loss by the next year. Bone loss was considered significant if bone mineral density (BMD) decline at the lumbar spine (LS) or femoral neck (FN) from a preâ or early perimenopausal baseline to 1â year after the E2 or FSH measurement was greater than the least detectable change. We used data from 1559 participants in the Study of Women’s Health Across the Nation and tested E2 and FSH as separate predictors using repeated measures modified Poisson regression. Adjusted for MT stage, age, race/ethnicity, and body mass index, women with lower E2 (and higher FSH) were more likely to lose BMD: At the LS, each halving of E2 and each doubling of FSH were associated with 10% and 39% greater risk of significant bone loss, respectively (pâ <â 0.0001 for each). At the FN, each halving of E2 and each doubling of FSH were associated with 12% (p = 0.01) and 27% (pâ <â 0.001) greater risk of significant bone loss. FSH was more informative than E2 (assessed by the area under the receiverâ operator curve) at identifying women who were more versus less likely to begin losing bone, especially at the LS. Prediction was better when hormones were measured in preâ or early perimenopause than in late perimenopause. Tracking withinâ individual change in either hormone did not predict onset of bone loss better than a single measure. We conclude that measuring FSH in the MT can help prospectively identify women with imminent or ongoing bone loss at the LS. © 2019 American Society for Bone and Mineral Research.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153118/1/jbmr3856_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153118/2/jbmr3856.pd