Risk Factors of Cardiovascular Disease as Predictors of Cardiomotor Profiles in Hispanic-Latinos Living with HIV

Background: People living with HIV are at increased risk of developing cardiovascular disease. Risk factors associated with cardiovascular disease negatively impact cardiovascular and muscular function. Therefore, this study aims to determine if cardiovascular disease risk factors are predictors of cardiomotor profiles in Hispanic-Latinos living with HIV. Subjects: A total of 176 participants were enrolled in this study. There were 134 males and 42 females with a mean age of 53.34 +/- 10.31 years old. Methods: Data was collected retrospectively from people living with HIV in San Juan, Puerto Rico from 2000-2020. Cardiovascular disease risk factors were collected by interview. In addition, the cardiovascular and locomotor components were collected using the Ross submaximal exercise test. Results: Hyperlipidemia was a significant predictor of treadmill time (B= -1.882, p=.034) and heart rate (B= -6.878, p<.001), whereas hypertension was a predictor of heart rate (B= -12.903, p=.026) and systolic blood pressure (B=12.263, p<.001). Hyperlipidemia was also a significant predictor of inclination (B= -1.707, p=.034). In addition, 57.4 % of the sample had at least one cardiovascular disease risk factor. Conclusion: Hyperlipidemia and hypertension should be considered in managing people living with HIV. This study indicated that hyperlipidemia and hypertension negatively affect cardiovascular and locomotor performance during exercise. Clinicians should be aware that exercise tolerance may be reduced in people with HIV and CVD risk factors; therefore, exercise prescription should be tailored and monitored accordingly

Lower limb muscle activation and kinematics modifications of young healthy adults while pushing a variable resistance sled

Introduction: The XPO Trainer used in this research is a novel device which provides low rolling resistance at low speeds with an immediate and automatic proportional increase in resistance with increased speed. Purpose: To examine the impact of using the XPO Trainer on gait and neuromuscular activation at low and high speeds in young, seemingly healthy adults. Materials and Methods: This work consisted of 48 healthy adults (age: 25.07 ± 3.46 years, weight: 148.2 ± 25.96 lbs, height: 66.57 ± 4.14 inches). Each participant wore accelerometers/gyroscopes sensors around each wrist and ankle, chest, and low back and surface electromyography (EMG) electrodes on their dominant leg over the quadriceps (QUAD), hamstring (HAM), anterior tibialis (TA), and gastrocnemius (GA). To initiate the tasks, participants walked then ran 40 feet with and without the XPO Trainer sled. Subjects did a total of 3 trials per tasks (total of 12) with one minute of rest between tasks to reduce fatigue factor. The data from the EMG and Mobility Lab sensors were then processed and compared through the SPSS 24 system for a repeated-measures ANOVA. Results: EMG- The QUAD muscle exhibited a significantly higher muscle activation (p ≤ .05) between walk (45.39 ± 24.43) and walk push (74.40 ± 56.73) tasks. Gait Parameters- There was a significant modification (p ≤ .05) between the different gait variables and tasks, including cadence, gait speed, stride length and trunk velocity while pushing the sled. Conclusion/Clinical Relevance: With the XPO Trainer being a novel device, it is important to understand how it affects the activation and response for muscles during different activities before using it as a training tool. Understanding the effect this particular sled can provide on the different components of the (temporospatial) gait parameters and muscle activation is valuable for a clinically appropriate application to specific populations.Supported by Texas Woman's University Small Grant Program

Differences in Temporal Gait Parameters When Walking on Even Surface Walkway, Treadmill, and Pushing a Constant Resistant Sled

Motorized treadmills and weighted sleds are employed in clinical settings to improve lower extremity strength, power, and endurance. However, little is known about how the spatio-temporal parameters compare when walking on an even surface walkway, walking on a treadmill, or pushing a sled. This study aimed to examine the variations in spatial and temporal gait parameters when walking on an even surface walkway (EW), on a treadmill (TW), and while pushing a sled (SP). Forty healthy subjects participated in this pilot study. The mean age and BMI of all participants were 24.39 (± 2.86) years and 68.26 (± 13.92) kg/m^2, respectively. Spatio-temporal parameters were gathered using the Mobility Lab ADPM software and six sensors containing accelerometers and gyroscopes. Participants were directed to walk at a normal and comfortable speed for 7 m on an even surface walkway for two trials. Next, the subjects walked on the treadmill for two trials at a speed based on age. For males aged <30 and females 20-40 years of age, the speed was 1.3 m/s. While for males aged 30 or older, the speed was set to 1.4 m/s. Finally, participants were instructed to walk at their normal pace while pushing a 60 lb sled for 9.1 meters (m). Treadmill walking provoked a significant increase in temporal variables, whereas pushing a sled significantly reduced the temporal variables. Treadmill walking resulted in a decrease in double limb support time and an increase in single-limb support time compared with even surface walking. Although cadence was greater when walking on a treadmill versus an even surface walkway, the difference may be attributed to a fixed speed on the treadmill, which was determined by age. Treadmill gait training is recommended for subjects that could benefit from an increase single limb support time to improve dynamic balance such as Parkinson patients. On the other hand, for those participants that dynamic activities are challenging, such as concussion and vestibular patients, pushing the sled will slow down gait parameters allowing gait training with an added resistance benefit. Finally, it has been proposed that further investigation should focus on the differences in lower extremity muscle activation and recruitment patterns under various walking conditions

Anteroposterior and mediolateral postural adaptations during single and duals tasks in healthy young adults

Dual tasks are fundamental and standard for daily walking and balance movements. However, further research is required to determine the comprehensive postural profile during challenging dual cognitive tasks. To distinguish the influence of dual cognitive tasks on anterior-posterior (AP) and mediolateral (ML) jerk (direction of sway), velocity, and distance in young adults with normal balance systems. Nineteen subjects took part in this inquiry (2 males and 17 females), with a mean age of 23.9+\- 2.3 years. The participants were instrumented using a lumbar accelerometer and a dynamometer designed to capture sway. All subjects completed eight balance tests comprising four single and four dual-cognitive tasks involving counting backward by three, starting at the number 100 (dual-task). Postural modifications were prominent in the AP direction, with a faster jerk, velocity, and considerable distance than in the ML direction. The introduction to challenging balance situations, including dual tasks, provoke AP direction adaptations to preserve balance through variations in AP parameters, indicating the engagement of the sensory reweighting system

Constant Resistance During Proportional Speed Provoked Higher Lower Limb Proximal Musculature Recruitment than Distal Musculature in Young Healthy Adults

The lack of exercise in society today often leads to severe muscle loss and poor physical performance. Training methods targeting specific weakened muscle groups can help prevent or counteract muscle loss. This study aimed to analyze how the lower extremity muscles are activated when pushing a sled with constant resistance at two different speeds. Twenty-six participants with an average age of 23.77 years consented to having electromyography surface electrodes placed along the gluteus maximus (GMax), gluteus medius (GMed), tibialis anterior (TA), and gastrocnemius (GA) of their dominant leg. Muscle activation levels were then measured while the participant walked and ran with and without sled resistance. The study results showed that muscle activation was comparable during all trials and was not influenced by speed or constant resistance. However, the muscle activation for GMax and GMed was significantly higher than the activation levels exhibited by GA and TA. While pushing a sled has been shown to impact all studied musculature similarly, adding resistance to the movement can affect gait parameters such as stride length and cadence. Our findings support the use of sled training in patients with hip pathologies who are seeking to strengthen their GMax and GMed

Constant Resistant at Different Speeds while Pushing a Sled Prompts Different Adaptations in Neuromuscular Timing on Back and Lower Limb Muscles

Resistance training (RT) is commonly used to target specific weakened muscle groups. Among the plethora of methods employed as RT, the current study focused on a sled that provides constant resistance proportional to speed. This study aimed to examine neuromuscular patterns of the lower extremity and trunk muscles in response to pushing a sled with constant resistance at two different speeds. Twenty-six young adults (average age, 23.8) participated in this study. Surface electromyography electrodes were placed on gluteus maximus (GMAX), gluteus medius (GMED), tibialis anterior (TA), gastrocnemius (GA), and erector spinae (lumbar and thoracic) of their dominant leg or side (unilateral at the same side as the dominant lower limb). Neuromuscular timing was collected during four tasks: walking, running, walking-pushing the sled (WP), and running-pushing the sled (RP). All gait activities were repeated twice, with self-selected speed and an equivalent distance of 40 feet. A MANOVA analysis showed that during WP, GMED and GMAX showed more neuromuscular recruitment than leg and trunk muscles when compared to walking. During RP, the thoracic musculature was significantly more involved than any other muscle during running. Based on our findings, we recommend that physiotherapists and trainers use this sled with constant resistance during walking in patients with pelvic or hip weakness. Further, we suggested utilizing the sled in subjects requiring mid-trunk activation at faster speeds, such as fast walking or running

Anthropometric characteristics, quality of life and functional capacity in adults living with HIV in Puerto Rico

Survival and longevity rates in people living with HIV (HIV+) have increased with the availability and use of antiretroviral therapy (ART). However, despite the above HIV+ adults treated with ART have a higher risk of developing dyslipidemia and high waist circumference. In addition, they have lower cardiorespiratory fitness, loss of muscle mass, reduced balance, and reduced functional capacity, which affects their quality of life. To explore the impact of balance perception, treadmill time, grip strength, body mass index (BMI), and waist-to-height ratio (WHtR) on quality of life in Latino Hispanic people living with HIV. This study recruited twenty-five participants from a community-based center, La Perla de Gran Precio, in San Juan, Puerto Rico, with the medical diagnosis of HIV. Descriptive measures were obtained for all variables of interest, and correlation and regression analyses were used to assess the associations between functional capacity, quality of life, and anthropometric measures. Result: Men had greater left- and right-hand grip strength than women (86.9±18.8, 56.9±26.8 kg; p=0.003 and 87.6±15.1 vs. 61.4±26.6 kg; p =0.004). Two anthropometric variables showed a trend toward a moderate positive correlation with quality of life:  WHtR (r= -0.38, p =0.12) and BMI (r= -0.38, p = p-0.14). Although gender differences in upper body strength are expected, handgrip strength is within the gender-specific average range of the general population. The integration of anthropometric characteristics and upper body strength when prescribing exercise must be considered since these factors influence functional capacity and quality of life among HIV+ adults

Blockade and Counterflow Supercurrent in exciton-condensate Josephson junctions

We demonstrate that perfect conversion between charged supercurrents in superconductors and neutral supercurrents in electron-hole pair condensates is possible via a new Andreev-like scattering mechanism. As a result, when two superconducting circuits are coupled through a bilayer exciton condensate, the superflow in both layers is drastically modified. Depending on the phase biases the supercurrents can be completely blocked or exhibit perfect drag.Comment: 4 pages, 2 figure

Positive cross-correlations induced by ferromagnetic contacts

Due to the Fermionic nature of carriers, correlations between electric currents flowing through two different contacts attached to a conductor present a negative sign. Possibility for positive cross-correlations has been demonstrated in hybrid normal/superconductor structures under certain conditions. In this paper we show that positive cross-correlations can be induced, if not already present, in such structures by employing ferromagnetic leads with magnetizations aligned anti-parallel to each other. We consider three-terminal hybrid structures and calculate the mean-square correlations of current fluctuations as a function of the bias voltage at finite temperature.Comment: 6 pages, 5 figures; accepted version by PRB, figures replace

A Deep Chandra ACIS Study of NGC 4151. II. The Innermost Emission Line Region and Strong Evidence for Radio Jet-NLR Cloud Collision

We have studied the X-ray emission within the inner 150 pc radius of NGC 4151 by constructing high spatial resolution emission line images of OVII, OVIII, and NeIX. These maps show extended structures that are spatially correlated with the radio outflow and optical [OIII] emission. We find strong evidence for jet--gas cloud interaction, including morphological correspondences with regions of X-ray enhancement, peaks of near-infrared [FeII] emission, and optical clouds. In these regions, moreover, we find evidence of elevated NeIX/OVII ratios; the X-ray emission of these regions also exceeds that expected from nuclear photoionization. Spectral fitting reveals the presence of a collisionally ionized component. The thermal energy of the hot gas suggests that >0.1% of the estimated jet power is deposited into the host interstellar medium through interaction between the radio jet and the dense medium of the circum-nuclear region. We find possible pressure equilibrium between the collisionally ionized hot gas and the photoionized line-emitting cool clouds. We also obtain constraints on the extended iron and silicon fluorescent emission. Both lines are spatially unresolved. The upper limit on the contribution of an extended emission region to the Fe Kalpha emission is <5% of the total, in disagreement with a previous claim that 65% of the Fe Kalpha emission originates in the extended narrow line region.Comment: Accepted for publication in ApJ. 28 pages, 9 figure