545 research outputs found
REACTIVE STRENGTH INDEX-MODIFIED: A COMPARISON BETWEEN SIX U.S. COLLEGIATE ATHLETIC TEAMS
The purpose of this study was to compare reactive strength index-modified (RSImod) between six U.S. collegiate sport teams. One hundred six athletes performed maximum effort countermovement jumps during unloaded and loaded conditions. RSImod measures for each team were compared using one-way ANOVAs, and Bonferroni post hoc tests where warranted. Statistically significant differences in RSImod values existed between teams during both unloaded (< 1kg) and loaded (20kg) conditions. The greatest RSImod values during both conditions were produced by men’s soccer and followed in order by baseball, women’s volleyball, men’s tennis, women’s soccer, and women’s tennis. The data indicate that athletes from different sports possess different reactive strength characteristics
A COMPARISON OF BASEBALL POSITIONAL DIFFERENCES WITH REACTIVE STRENGTH INDEX-MODIFIED
The purpose of this study was to examine positional differences amongst 29 baseball players using the Reactive Strength Index-modified (RSImod) values during unloaded and loaded countermovement jumps (CMJ). A secondary purpose was to determine the relationship between other jump performance characteristics and RSImod values. All athletes underwent CMJ testing and RSImod values were compared between pitchers and position players. The loaded condition CMJ produced statistically different RSImod values between the two groups. Scaled peak force was somewhat more strongly related to RSImod than rate of force development (RFD). The current study indicates that position players may possess higher reactive strength capabilities than pitchers and scaled peak force may be more important than RFD in determining reactive strength characteristics
THE RELATIONSHIP OF THE REACTIVE STRENGTH INDEX-MODIFIED AND MEASURES OF FORCE DEVELOPMENT IN THE ISOMETRIC MID-THIGH PULL
Reactive strength index-modified (RSImod) may be an important variable to measure in the performance testing and monitoring of athletes, and very little work has examined this particular variable. One hundred six Division-I collegiate athletes performed countermovement jumps and the isometric mid-thigh pull. The relationship between the RSImod and variables from the isometric mid-thigh pull representative of explosive performance were evaluated with Pearson’s r. Relationships between RSImod and variables related to explosiveness ranged from moderate to large. Maximum and relative maximum strength had the strongest correlations to RSImod. RSImod appears to be a measure of explosiveness. Furthermore, an athlete’s isometric strength may be an indicator of their reactive strength
THE USE OF REACTIVE STRENGTH INDEX-MODIFIED AS AN EXPLOSIVE PERFORMANCE MEASUREMENT IN MALE AND FEMALE ATHLETES
This study examined the reliability of reactive strength index-modified (RSImod), relationships between RSImod and force-time variables, and difference in RSImod between male and female collegiate athletes. 106 Division I collegiate athletes performed unloaded and loaded countermovement jumps. Intraclass correlation coefficients and coefficients of variation were used to establish the reliability of RSImod. Correlations were calculated between RSImod and rate of force development, peak force, and peak power. RSImod appears to be a reliable performance measurement in male and female athletes. Furthermore, RSImod has moderate to very large relationships with rate of force development, peak force, and peak power. Statistically significant differences in RSImod existed between males and females during both unloaded and loaded CMJs
West Nile virus growth is independent of autophagy activation
AbstractWest Nile virus (WNV) is an arthropod-borne virus with a worldwide distribution that causes neurologic disease and death. Autophagy is a cellular homeostatic mechanism involved in antiviral responses but can be subverted to support viral growth as well. We show that autophagy is induced by WNV infection in cell culture and in primary neuron cultures. Following WNV infection, lysosomes co-localize with autophagosomes resulting in LC3B-II turnover and autolysosomal acidification. However, activation or inhibition of autophagy has no significant effect on WNV growth but pharmacologic inhibition of PI3 kinases associated with autophagy reduce WNV growth. Basal levels of p62/sequestosome1(SQSTM1) do not significantly change following WNV-induced autophagy activation, but p62 is turned over or degraded by autophagy activation implying that p62 expression is increased following WNV-infection. These data show that WNV-induces autophagy but viral growth is independent of autophagy activation suggesting that WNV-specific interactions with autophagy have diverged from other flaviviruses
Recommended from our members
Technoeconomic and life-cycle analysis of single-step catalytic conversion of wet ethanol into fungible fuel blendstocks
Technoeconomic and life-cycle analyses are presented for catalytic conversion of ethanol to fungible hydrocarbon fuel blendstocks, informed by advances in catalyst and process development. Whereas prior work toward this end focused on 3-step processes featuring dehydration, oligomerization, and hydrogenation, the consolidated alcohol dehydration and oligomerization (CADO) approach described here results in 1-step conversion of wet ethanol vapor (40 wt% in water) to hydrocarbons and water over a metal-modified zeolite catalyst. A development project increased liquid hydrocarbon yields from 36% of theoretical to >80%, reduced catalyst cost by an order of magnitude, scaled up the process by 300-fold, and reduced projected costs of ethanol conversion 12-fold. Current CADO products conform most closely to gasoline blendstocks, but can be blended with jet fuel at low levels today, and could potentially be blended at higher levels in the future. Operating plus annualized capital costs for conversion of wet ethanol to fungible blendstocks are estimated at 1.44/GJ in the future, similar to the unit energy cost of producing anhydrous ethanol from wet ethanol (100 per barrel but not at 60 per barrel. Life-cycle greenhouse gas emission reductions for CADO-derived hydrocarbon blendstocks closely follow those for the ethanol feedstock
Intracranial meningiomas: an update of the 2021 World Health Organization classifications and review of management with a focus on radiation therapy
Meningiomas account for approximately one third of all primary intracranial tumors. Arising from the cells of the arachnoid mater, these neoplasms are found along meningeal surfaces within the calvarium and spinal canal. Many are discovered incidentally, and most are idiopathic, although risk factors associated with meningioma development include age, sex, prior radiation exposure, and familial genetic diseases. The World Health Organization grading system is based on histologic criteria, and are as follows: grade 1 meningiomas, a benign subtype; grade 2 meningiomas, which are of intermediately aggressive behavior and usually manifest histologic atypia; and grade 3, which demonstrate aggressive malignant behavior. Management is heavily dependent on tumor location, grade, and symptomatology. While many imaging-defined low grade appearing meningiomas are suitable for observation with serial imaging, others require aggressive management with surgery and adjuvant radiotherapy. For patients needing intervention, surgery is the optimal definitive approach with adjuvant radiation therapy guided by extent of resection, tumor grade, and location in addition to patient specific factors such as life expectancy. For grade 1 lesions, radiation can also be used as a monotherapy in the form of stereotactic radiosurgery or standard fractionated radiation therapy depending on tumor size, anatomic location, and proximity to dose-limiting organs at risk. Optimal management is paramount because of the generally long life-expectancy of patients with meningioma and the morbidity that can arise from tumor growth and recurrence as well as therapy itself
The tissue-type plasminogen activator-plasminogen activator inhibitor 1 complex promotes neurovascular injury in brain trauma: evidence from mice and humans
The neurovascular unit provides a dynamic interface between the circulation and central nervous system. Disruption of neurovascular integrity occurs in numerous brain pathologies including neurotrauma and ischaemic stroke. Tissue plasminogen activator is a serine protease that converts plasminogen to plasmin, a protease that dissolves blood clots. Besides its role in fibrinolysis, tissue plasminogen activator is abundantly expressed in the brain where it mediates extracellular proteolysis. However, proteolytically active tissue plasminogen activator also promotes neurovascular disruption after ischaemic stroke; the molecular mechanisms of this process are still unclear. Tissue plasminogen activator is naturally inhibited by serine protease inhibitors (serpins): plasminogen activator inhibitor-1, neuroserpin or protease nexin-1 that results in the formation of serpin:protease complexes. Proteases and serpin:protease complexes are cleared through high-affinity binding to low-density lipoprotein receptors, but their binding to these receptors can also transmit extracellular signals across the plasma membrane. The matrix metalloproteinases are the second major proteolytic system in the mammalian brain, and like tissue plasminogen activators are pivotal to neurological function but can also degrade structures of the neurovascular unit after injury. Herein, we show that tissue plasminogen activator potentiates neurovascular damage in a dose-dependent manner in a mouse model of neurotrauma. Surprisingly, inhibition of activity following administration of plasminogen activator inhibitor-1 significantly increased cerebrovascular permeability. This led to our finding that formation of complexes between tissue plasminogen activator and plasminogen activator inhibitor-1 in the brain parenchyma facilitates post-traumatic cerebrovascular damage. We demonstrate that following trauma, the complex binds to low-density lipoprotein receptors, triggering the induction of matrix metalloproteinase-3. Accordingly, pharmacological inhibition of matrix metalloproteinase-3 attenuates neurovascular permeability and improves neurological function in injured mice. Our results are clinically relevant, because concentrations of tissue plasminogen activator: plasminogen activator inhibitor-1 complex and matrix metalloproteinase-3 are significantly elevated in cerebrospinal fluid of trauma patients and correlate with neurological outcome. In a separate study, we found that matrix metalloproteinase-3 and albumin, a marker of cerebrovascular damage, were significantly increased in brain tissue of patients with neurotrauma. Perturbation of neurovascular homeostasis causing oedema, inflammation and cell death is an important cause of acute and long-term neurological dysfunction after trauma. A role for the tissue plasminogen activator-matrix metalloproteinase axis in promoting neurovascular disruption after neurotrauma has not been described thus far. Targeting tissue plasminogen activator: plasminogen activator inhibitor-1 complex signalling or downstream matrix metalloproteinase-3 induction may provide viable therapeutic strategies to reduce cerebrovascular permeability after neurotraum
Largest GWAS of PTSD (N=20 070) yields genetic overlap with schizophrenia and sex differences in heritability
The Psychiatric Genomics Consortium-Posttraumatic Stress Disorder group (PGC-
PTSD) combined genome-wide case–control molecular genetic data across 11
multiethnic studies to quantify PTSD heritability, to examine potential shared
genetic risk with schizophrenia, bipolar disorder, and major depressive
disorder and to identify risk loci for PTSD. Examining 20 730 individuals, we
report a molecular genetics-based heritability estimate (h2SNP) for European-
American females of 29% that is similar to h2SNP for schizophrenia and is
substantially higher than h2SNP in European-American males (estimate not
distinguishable from zero). We found strong evidence of overlapping genetic
risk between PTSD and schizophrenia along with more modest evidence of overlap
with bipolar and major depressive disorder. No single-nucleotide polymorphisms
(SNPs) exceeded genome-wide significance in the transethnic (overall) meta-
analysis and we do not replicate previously reported associations. Still, SNP-
level summary statistics made available here afford the best-available
molecular genetic index of PTSD—for both European- and African-American
individuals—and can be used in polygenic risk prediction and genetic
correlation studies of diverse phenotypes. Publication of summary statistics
for ∼10 000 African Americans contributes to the broader goal of increased
ancestral diversity in genomic data resources. In sum, the results demonstrate
genetic influences on the development of PTSD, identify shared genetic risk
between PTSD and other psychiatric disorders and highlight the importance of
multiethnic/racial samples. As has been the case with schizophrenia and other
complex genetic disorders, larger sample sizes are needed to identify specific
risk loci
- …