630 research outputs found
Initial KAATSU Cuff Tightness: Effect of Limb Anthropometrics on Blood Flow Restriction
abstractINTRODUCTION KAATSU training involves low load (20%1RM) resistance exercise combined with partial blood flow restriction (BFR). BFR is achieved by positioning a specially designed pneumatic cuff around the proximal aspect of the limb, cinching it to an initial cuff tightness (ICT), then inflating the cuff to a higher restrictive training pressure. ICTs can potentially impact the degree of BFR (%BFR) caused at the higher training pressures, yet many studies use the same ICTs for all subjects (1). Identifying that discrepancies in %BFR exist between subjects with different limb anthropometrics is an important step in moving toward standardization of BFR dose for KAATSU training prescription. The purpose of this study was to identify variation in %BFR between subjects experiencing the same ICT and what limb anthropometrics (circumference, muscle, and fat composition) may be determinants.
METHODS Forty-two volunteers (26 men, 16 women) provided informed consent. Caliper skin folds, Gulick tape circumferences, and peripheral quantitative computed tomography (pQCT) scans were performed on the randomly assigned ipsilateral arm and leg at the level of the KAATSU cuff application. %BFR was measured via pulse-wave Doppler ultrasound at baseline (no cuff) and at an ICT of 30 mmHg. Variable relationships were assessed using Pearson correlations and stepwise linear regression. RESULTS The average %BFR (avgĀ±st. dev.) for the arm and leg was 16.01Ā±11.42% and 16.75Ā±9.27% with a range of 46.66% and 36.41%, respectively. The dependent variable for regression analysis was %BFR. In the arm, pQCT-determined muscle (R2=0.614) and fat composition (R2=0.587) were significant (p<0.05) determinants of %BFR. Circumference was also a determinant (R2=0.163). There were no significant correlations between %BFR and the anthropometrics for the leg. pQCT fat composition and sum of skin folds correlated significantly (r=0.915, p<0.05). pQCT circumference and Gulick circumference measures correlated significantly (r=0.991, p<0.05).
DISCUSSION
Conflicting BFR training results have been reported in the literature. A potential cause could be universal ICT usage causing some individuals to receive an inadequate training stimulus. Individuals using a 30 mmHg ICT will experience different %BFR when limb anthropometrics vary. Thus a method of assigning ICTs specific to individualsā anthropometric characteristics is needed to ensure equally potent stimuli. Skin fold measures and circumference measures were highly correlated with pQCT data. As a result, skin fold and Gulick circumference measures can be used to predict arm composition at the level of the cuff and may inform prescription of appropriate ICTs that result in more consistent initial %BFR across individuals
KAATSU Cuff Tightness and Limb Anthropometry: Effect on Blood Flow Restriction
abstractKAATSU resistance training involves low loads (20%1RM) and partial blood flow restriction (BFR). When applying a BFR cuff, the initial cuff tightness (ICT) is important. ICTs can potentially impact the degree of BFR (%BFR) caused by the subsequent inflation to the target training pressures. Itās known that limb anthropometrics can affect the amount of BFR that is produced at specific pressures. Understanding the interaction between limb anthropometrics and ICT is an important first step in standardizing BFR dose between individuals for KAATSU training prescription.
Purpose: To determine what limb anthropometrics (circumference, muscle or fat composition) have the greatest effect on %BFR with various ICTs.
Methods: Forty-two volunteers (26 men, 16 women) provided informed consent. Caliper skin folds (anterior and posterior), Gulick tape circumferences, and peripheral quantitative computed tomography (pQCT) scans were performed on the randomly assigned ipsilateral arm and leg at the level of the KAATSU cuff. %BFR was measured via pulse-wave Doppler ultrasound at baseline (no cuff) and at 5 ICT pressures (20, 30, 40, 50 and 60mmHg). Variable relationships were assessed using Pearson correlations and stepwise linear regression.
Results: The dependent variable for regression analysis was %BFR at each ICT. pQCT-determined muscle (R2= .147, .614, .445, .360, & .232, respectively) and fat composition (R2= .138, .587, .429, .338, & .220, respectively) were significant (p<.05) determinants of BFR at all ICT pressures in the arm. At 30mmHg, circumference was also a determinant (R2=.163). There were no significant correlations between %BFR and any of the ICT pressures for the leg. pQCT fat composition and sum of skin folds correlated significantly (r=.915, p<.05). pQCT circumference and Gulick circumference measures correlated significantly (r=.991, p<.05).
Conclusion: Arm anthropometrics impact the %BFR created by 5 ICTs in the arm. Skin fold measures and circumference measures were highly correlated with pQCT data. As a result, skin fold and Gulick circumference measures can be used to predict arm composition at the level of the cuff and may inform prescription of appropriate ICTs that result in more consistent initial %BFR across individuals
A Transcriptional Program Mediating Entry into Cellular Quiescence
The balance of quiescence and cell division is critical for tissue homeostasis and organismal health. Serum stimulation of fibroblasts is well studied as a classic model of entry into the cell division cycle, but the induction of cellular quiescence, such as by serum deprivation (SD), is much less understood. Here we show that SS and SD activate distinct early transcriptional responses genome-wide that converge on a late symmetric transcriptional program. Several serum deprivation early response genes (SDERGs), including the putative tumor suppressor genes SALL2 and MXI1, are required for cessation of DNA synthesis in response to SD and induction of additional SD genes. SDERGs are coordinately repressed in many types of human cancers compared to their normal counterparts, and repression of SDERGs predicts increased risk of cancer progression and death in human breast cancers. These results identify a gene expression program uniquely responsive to loss of growth factor signaling; members of SDERGs may constitute novel growth inhibitors that prevent cancer
VCU Job Shadowing
Job shadowing is an initiative aimed at bolstering students\u27 career preparedness through an immersive exploration of the multifaceted landscape of career opportunities within higher education. By facilitating these experiential learning opportunities, this program endeavors to achieve a twofold objective. Firstly, it seeks to enhance the student experience at Virginia Commonwealth University (VCU) by cultivating meaningful interactions between students and VCU\u27s typically non-student-facing staff and faculty members. Secondly, by facilitating direct engagement with our students, it is our aspiration that every member of the VCU community, regardless of their traditional roles, will have the opportunity to support our students\u27 personal and academic growth
A Multimodal Dataset of 21,412 Recorded Nights for Sleep and Respiratory Research
This study introduces a novel, rich dataset obtained from home sleep apnea
tests using the FDA-approved WatchPAT-300 device, collected from 7,077
participants over 21,412 nights. The dataset comprises three levels of sleep
data: raw multi-channel time-series from sensors, annotated sleep events, and
computed summary statistics, which include 447 features related to sleep
architecture, sleep apnea, and heart rate variability (HRV). We present
reference values for Apnea/Hypopnea Index (AHI), sleep efficiency, Wake After
Sleep Onset (WASO), and HRV sample entropy, stratified by age and sex.
Moreover, we demonstrate that the dataset improves the predictive capability
for various health related traits, including body composition, bone density,
blood sugar levels and cardiovascular health. These results illustrate the
dataset's potential to advance sleep research, personalized healthcare, and
machine learning applications in biomedicine.Comment: Extended Abstract presented at Machine Learning for Health (ML4H)
symposium 2023, December 10th, 2023, New Orleans, United States, 14 page
Semiprojectivity with and without a group action
The equivariant version of semiprojectivity was recently introduced by the
first author. We study properties of this notion, in particular its relation to
ordinary semiprojectivity of the crossed product and of the algebra itself.
We show that equivariant semiprojectivity is preserved when the action is
restricted to a cocompact subgroup. Thus, if a second countable compact group
acts semiprojectively on a C*-algebra , then must be semiprojective.
This fails for noncompact groups: we construct a semiprojective action of the
integers on a nonsemiprojective C*-algebra.
We also study equivariant projectivity and obtain analogous results, however
with fewer restrictions on the subgroup. For example, if a discrete group acts
projectively on a C*-algebra , then must be projective. This is in
contrast to the semiprojective case.
We show that the crossed product by a semiprojective action of a finite group
on a unital C*-algebra is a semiprojective C*-algebra. We give examples to show
that this does not generalize to all compact groups.Comment: 38 page
Charged Free Fermions, Vertex Operators and Classical Theory of Conjugate Nets
We show that the quantum field theoretical formulation of the -function
theory has a geometrical interpretation within the classical transformation
theory of conjugate nets. In particular, we prove that i) the partial charge
transformations preserving the neutral sector are Laplace transformations, ii)
the basic vertex operators are Levy and adjoint Levy transformations and iii)
the diagonal soliton vertex operators generate fundamental transformations. We
also show that the bilinear identity for the multicomponent
Kadomtsev-Petviashvili hierarchy becomes, through a generalized Miwa map, a
bilinear identity for the multidimensional quadrilateral lattice equations.Comment: 28 pages, 3 Postscript figure
Estimating Cell Depth from Somatic Mutations
The depth of a cell of a multicellular organism is the number of cell divisions it underwent since the zygote, and knowing this basic cell property would help address fundamental problems in several areas of biology. At present, the depths of the vast majority of human and mouse cell types are unknown. Here, we show a method for estimating the depth of a cell by analyzing somatic mutations in its microsatellites, and provide to our knowledge for the first time reliable depth estimates for several cells types in mice. According to our estimates, the average depth of oocytes is 29, consistent with previous estimates. The average depth of B cells ranges from 34 to 79, linearly related to the mouse age, suggesting a rate of one cell division per day. In contrast, various types of adult stem cells underwent on average fewer cell divisions, supporting the notion that adult stem cells are relatively quiescent. Our method for depth estimation opens a window for revealing tissue turnover rates in animals, including humans, which has important implications for our knowledge of the body under physiological and pathological conditions
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