Contraction Levels Research Articles

Equity in government contracting: Analyzing the performance of small disadvantaged businesses

AbstractSet aside programs, which preference disadvantaged businesses, have long been among the largest government equity programs in the United States. Set asides ensure government revenues spur economic growth in firms and communities that have traditionally lacked representation in systems of power. However, there has been skepticism about whether set aside programs are compatible with the efficiency objectives of government contracting. Few empirical studies have assessed the comparative performance of small, disadvantaged businesses and other firms to determine if there are differences. Using contract level data from the Federal Procurement Data System: Next Generation, we test whether set aside contracts are associated with a reduction in the government's ability to secure “best value.” We find few performance differences between small, disadvantaged businesses, and other vendors across a range of goods and services, suggesting mutual benefits and no outsized risks when governments engage in contracts with disadvantaged firms.

Investigation of the relationship between isokinetic lower extremity strength and the vertical jump parameter in elite women football players

Background and Study Aim. It can be said that recently, with the popularity of women's football and playing at a professional level, physical and physiological needs have increased. In this context, this study was conducted to examine the relationship between isokinetic lower extremity strength and vertical jump parameters in elite female football players. Material and Methods. The model of the research was the relational survey model, one of the survey models. The research group consisted of 26 volunteer professional female football players competing at the Turkish women's super league level. The maximum strength of the knee extensor and flexor muscles of female soccer players was measured using an isokinetic dynamometer device (Cybex NORM®, Humac, CA, USA) that allows the recording of instant isokinetic torque. The vertical jump test data of the female football players were determined with the Fusion Sport-Smart Jump brand jump mat. While SPSS 25.0 package program was used for statistical analysis evaluation, correlation analysis was applied to compare the relationship between isokinetic lower extremity strength and vertical jump parameter. Results. When the participants' vertical jump, right knee flexion and extension degrees were examined, a moderate positive correlation was found between the vertical jump parameter and the 240s Flexion Right %Body Weight values, and no relationship was found between the other parameters and the vertical jump. A moderate positive correlation was detected between the vertical jump parameter and 240s Flexion Left %Body Weight. Another moderate positive correlation was found between the vertical jump parameter and 240s Extension Left %Body Weight values. At the same time, no relation was found between other parameters and vertical jumps. Conclusions. As a result, when the study results were evaluated, a positive relationship was determined between vertical jump and right knee flexion parameters and similarly left knee flexion-extension parameters. Based on this situation, it was concluded that the contraction levels of the lower extremity strength, which plays an important role in determining the performance in the football branch, contribute positively to the jump performance.

Gender differences on effects of forearm rotation on compressive stiffness of flexor carpi ulnaris during submaximal handgrip contractions.

Little is known about gender differences in stiffness of forearm muscles during voluntary actions. This study aimed to investigate the effect of forearm rotation on flexor carpi ulnaris (FCU) stiffness in men and women during submaximal handgrip contractions. During a single session, measurements were made on 20 young participants (9 females). Two positions of the forearm were compared in random order with the elbow flexed 90 degrees: (i) neutral position and (ii) maximal supination. In each position, participants performed two submaximal handgrip contractions at 25% and 50% of maximal voluntary contraction, while compressive stiffness was collected using a hand myometer (MyotonPRO). A mixed repeated measurement ANOVA was applied to assess the interaction between gender, forearm position, and contraction intensity. The FCU stiffness is affected by handgrip contraction intensity (p < 0.001), gender (p < 0.001), BMI (p = 0.009), and forearm rotation (p = 0.007). Only the gender factor was found to have significant interaction with forearm rotation (p = 0.037). Men's FCU was stiffer than women's in both positions and contraction intensities (p < 0.05). Only in men a significant increase in FCU stiffness was observed when comparing contraction intensities at both forearm positions (p < 0.05), as well as when the forearm was rotated from neutral to supine at both intensities (p < 0.05). In conclusion, FCU stiffness during handgrip contraction differed significantly between men and women. Women have fewer stiffness changes in FCU when performing different levels of handgrip contraction. We also observed that only men increased FCU stiffness by changing the forearm position from neutral to supine position for both handgrip intensities.

Human-machine interface for two-dimensional steering control with the auricular muscles.

Human-machine interfaces (HMIs) can be used to decode a user's motor intention to control an external device. People that suffer from motor disabilities, such as spinal cord injury, can benefit from the uses of these interfaces. While many solutions can be found in this direction, there is still room for improvement both from a decoding, hardware, and subject-motor learning perspective. Here we show, in a series of experiments with non-disabled participants, a novel decoding and training paradigm allowing naïve participants to use their auricular muscles (AM) to control two degrees of freedom with a virtual cursor. AMs are particularly interesting because they are vestigial muscles and are often preserved after neurological diseases. Our method relies on the use of surface electromyographic records and the use of contraction levels of both AMs to modulate the velocity and direction of a cursor in a two-dimensional paradigm. We used a locking mechanism to fix the current position of each axis separately to enable the user to stop the cursor at a certain location. A five-session training procedure (20-30 min per session) with a 2D center-out task was performed by five volunteers. All participants increased their success rate (Initial: 52.78 ± 5.56%; Final: 72.22 ± 6.67%; median ± median absolute deviation) and their trajectory performances throughout the training. We implemented a dual task with visual distractors to assess the mental challenge of controlling while executing another task; our results suggest that the participants could perform the task in cognitively demanding conditions (success rate of 66.67 ± 5.56%). Finally, using the Nasa Task Load Index questionnaire, we found that participants reported lower mental demand and effort in the last two sessions. To summarize, all subjects could learn to control the movement of a cursor with two degrees of freedom using their AM, with a low impact on the cognitive load. Our study is a first step in developing AM-based decoders for HMIs for people with motor disabilities, such as spinal cord injury.

Curvature of gastrocnemius muscle fascicles as function of muscle-tendon complex length and contraction in humans.

It has been shown that muscle fascicle curvature increases with increasing contraction level and decreasing muscle-tendon complex length. The analyses were done with limited examination windows concerning contraction level, muscle-tendon complex length, and/or intramuscular position of ultrasound imaging. With this study we aimed to investigate the correlation between fascicle arching and contraction, muscle-tendon complex length and their associated architectural parameters in gastrocnemius muscles to develop hypotheses concerning the fundamental mechanism of fascicle curving. Twelve participants were tested in five different positions (90°/105°*, 90°/90°*, 135°/90°*, 170°/90°*, and 170°/75°*; *knee/ankle angle). They performed isometric contractions at four different contraction levels (5%, 25%, 50%, and 75% of maximum voluntary contraction) in each position. Panoramic ultrasound images of gastrocnemius muscles were collected at rest and during constant contraction. Aponeuroses and fascicles were tracked in all ultrasound images and the parameters fascicle curvature, muscle-tendon complex strain, contraction level, pennation angle, fascicle length, fascicle strain, intramuscular position, sex and age group were analyzed by linear mixed effect models. Mean fascicle curvature of the medial gastrocnemius increased with contraction level (+5 m-1 from 0% to 100%; p = 0.006). Muscle-tendon complex length had no significant impact on mean fascicle curvature. Mean pennation angle (2.2 m-1 per 10°; p < 0.001), inverse mean fascicle length (20 m-1 per cm-1 ; p = 0.003), and mean fascicle strain (-0.07 m-1 per +10%; p = 0.004) correlated with mean fascicle curvature. Evidence has also been found for intermuscular, intramuscular, and sex-specific intramuscular differences of fascicle curving. Pennation angle and the inverse fascicle length show the highest predictive capacities for fascicle curving. Due to the strong correlations between pennation angle and fascicle curvature and the intramuscular pattern of curving we suggest for future studies to examine correlations between fascicle curvature and intramuscular fluid pressure.

Calculating sample entropy from isometric torque signals: methodological considerations and recommendations.

We investigated the effect of different sampling frequencies, input parameters and observation times for sample entropy (SaEn) calculated on torque data recorded from a submaximal isometric contraction. Forty-six participants performed sustained isometric knee flexion at 20% of their maximal contraction level and torque data was sampled at 1,000Hz for 180s. Power spectral analysis was used to determine the appropriate sampling frequency. The time series were downsampled to 750, 500, 250, 100, 50, and 25Hz to investigate the effect of different sampling frequency. Relative parameter consistency was investigated using combinations of vector lengths of two and three and tolerance limits of 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, and 0.4, and data lengths between 500 and 18,000 data points. The effect of different observations times was evaluated using Bland-Altman plot for observations times between 5 and 90s. SaEn increased at sampling frequencies below 100Hz and was unaltered above 250Hz. In agreement with the power spectral analysis, this advocates for a sampling frequency between 100 and 250Hz. Relative consistency was observed across the tested parameters and at least 30s of observation time was required for a valid calculation of SaEn from torque data.

Association between force fluctuation during isometric ankle abduction and variability of neural drive in peroneus muscles

Analyzing motor unit (MU) activities of peroneus muscles may reveal the causes of force control deficits of ankle eversion. This study aimed to examine peroneus muscles' MU discharge characteristics and associations between force fluctuation and variability of the neural drive in healthy participants. Thirty-one healthy males participated in this study. MU activities were identified from high-density surface electromyography of peroneus muscles during ankle eversion at 15 and 30% of maximal voluntary contraction (MVC). Participants increased the contraction level until reaching the target and held it for 15s. The central 10s of the hold phase were used for analysis. A cumulative spike train (CST) was calculated using MU firings. Variabilities of the force and CST are represented by the coefficient of variation (CoV). Spearman's rank correlation coefficient was used to assess the association between CoV of force and CoV of CST. For 15 and 30 % MVC trials, CoV of force was 1.86±1.59 and 1.57±1.26%, and CoV of CST was 5.01±3.24 and 4.51±2.78%, respectively. The correlation was significant at 15% (rho=0.27, p<0.001) and 30% (rho=0.32, p<0.001) MVC. Our findings suggest that in peroneus muscles, force fluctuation weakly to moderately correlates with neural drive variability.

Antischistosomal effects of green and chemically synthesized silver nanoparticles: In vitro and in vivo murine model

Schistosomiasis is one of the most important neglected tropical diseases in Africa, caused by blood fluke, Schistosoma sp. The use of nanotechnology in the treatment of this type of disease is urgently important to avoid the unwanted side effects of chemotherapy. The present study aimed to evaluate the efficacy of green silver nanoparticles (G-AgNPs), fabricated by (Calotropis procera), comparing with both chemically prepared silver ones (C-AgNPs) and Praziquantel (PZQ) treatments. The study included in vitro and in vivo evaluations. In in vitro study, 4 groups of schistosome worms were exposed to treatments as follows: the first one with a dose of PZQ (0.2 µg/ml), the 2nd and 3rd groups with different concentrations of G-AgNPs and C-AgNPs, respectively and the last one act as a negative control group. In in vivo study, six groups of mice were infected and then treated as follows: the first one with a dose of PZQ, the second with G-AgNPs, the third with C-AgNPs, the fourth with G-AgNPs plus a half dose of PZQ, the fifth with C-AgNPs accompanied by a half dose of PZQ, and the last group acted as a positive control group. The parasitological (worm burden, egg count & oogram) and histopathological parameters (hepatic granuloma profile) were used to evaluate antischistosomal activities in experimental groups. Additionally, the subsequent ultrastructural alterations were observed in adult worms using scanning electron microscopy (SEM). Transmission electron microscopy analysis showed that G-AgNPs and C-AgNPs have 8–25 and 8–11 nm in diameter, respectively, besides, fourier transform infrared analysis (FTIR) revealed the presence of organic compounds (aromatic ring groups) which act as capping agents around the surfaces of biogenic silver nanoparticles. In in vitro experiment, adult worms incubated either with G-AgNPs or C-AgNPs at concentrations higher than 100 µg/ml or 80 µg/ml, respectively, showed full mortality of parasites after 24 h. In the infected treated groups (with G-AgNPs plus PZQ & C-AgNPs plus PZQ) showed the most significant reduction in the total worm burdens (92.17% & 90.52%, respectively). Combined treatment with C-AgNPs and PZQ showed the highest value of dead eggs (93,6%), followed by G-AgNPs plus PZQ-treated one (91%). This study showed that mice treated with G-AgNPs plus PZQ significantly has the highest percentage of reduction in granuloma size and count (64.59%, 70.14%, respectively). Both G-AgNPs plus PZQ-treated & C-AgNPs plus PZQ treated groups showed the highest similar values of reduction percentage of total ova count in tissues (98.90% & 98.62%, respectively). Concerning SEM, G-AgNPs-treated worms showed more variability in ultrastructural alterations than G-AgNPs plus PZQ-treated one, besides, worms treated with C-AgNPs plus PZQ exhibited the maximum level of contractions or (shrinkage) as a major impact.

Influence of internal muscle properties on muscle shape change and gearing in the human gastrocnemii.

Skeletal muscles bulge when they contract. These three-dimensional shape changes, coupled with fiber rotation, influence a muscle's mechanical performance by uncoupling fiber velocity from muscle belly velocity (i.e., gearing). Muscle shape change and gearing are likely mediated by the interaction between internal muscle properties and contractile forces. Muscles with greater stiffness and intermuscular fat, due to aging or disuse, may limit a muscle's ability to bulge in width, subsequently causing higher gearing. The aim of this study was to determine the influence of internal muscle properties on shape change, fiber rotation, and gearing in the medial (MG) and lateral gastrocnemii (LG) during isometric plantar flexion contractions. Multimodal imaging techniques were used to measure muscle shear modulus, intramuscular fat, and fat-corrected physiological cross-sectional area (PCSA) at rest, as well as synchronous muscle architecture changes during submaximal and maximal contractions in the MG and LG of 20 young (24 ± 3 yr) and 13 older (70 ± 4 yr) participants. Fat-corrected PCSA was positively associated with fiber rotation, gearing, and changes in thickness during submaximal contractions, but it was negatively associated with changes in thickness at maximal contractions. Muscle stiffness and intramuscular fat were related to muscle bulging and reduced fiber rotation, respectively, but only at high forces. Furthermore, the MG and LG had varied internal muscle properties, which may relate to the differing shape changes, fiber rotations, and gearing behaviors observed at each contraction level. These results indicate that internal muscle properties may play an important role in mediating in vivo muscle shape change and gearing, especially during high-force contractions.NEW & NOTEWORTHY Here, we measured internal muscle properties in vivo to determine their influence on the varying shape change and gearing behaviors in the synergistic gastrocnemii muscles. These relationships have previously only been hypothesized or examined within isolated muscles during supramaximal contractions. Our results contribute to a more comprehensive understanding of the factors that influence a muscle's mechanical response to force with implications for preventing or treating muscle deficits associated with aging, disease, and disuse.

THE EFFECTS OF NEUROTICISM ON APPROACH-AVOIDANCE-RELATED MOTOR BEHAVIOR

In the present study, we aimed to investigate whether positive emotional stimuli may affect high and low neuroticism individuals’ maximal voluntary contraction (MVC) level of the biceps brachii muscle, which is considered a motor representation of approach behavior. The sample consisted of 36 right-handed individuals (12 females) ranging in age from 18 to 27 (M= 23.516 [2.120]). Participants completed items from the Big Five Factor Personality Inventory concerning Neuroticism. After completing the psychometric test, we exposed participants to the high valance low arousal pictures selected from the International Affective Picture System (IAPS) via Biotrace+ software during the execution of arm flexions. Participants made 2 MVC attempts for each experimental condition lasting 6 seconds and rested 3 minutes between MVC attempts to eliminate the effect of fatigue. Results of Pearson correlation analysis revealed that the percent change of MVC was positively associated with neuroticism (r= .368, p&lt; .05). The results also showed that the percent change of MVC of the high neuroticism group was significantly greater than the percent change of the low neuroticism group [t(36)= -2.449, p= .020]. Results provided some support for our hypothesis. Hence the data demonstrated that positive emotional stimuli decreased the MVC of the biceps brachii muscle in individuals with low neuroticism. On the contrary, MVC levels of high neuroticism individuals remained almost stable in response to positive emotional stimuli.

The interaction between changes of muscle activation and cortical network dynamics during isometric elbow contraction: a sEMG and fNIRS study.

Objective: The relationship between muscle activation during motor tasks and cerebral cortical activity remains poorly understood. The aim of this study was to investigate the correlation between brain network connectivity and the non-linear characteristics of muscle activation changes during different levels of isometric contractions. Methods: Twenty-one healthy subjects were recruited and were asked to perform isometric elbow contractions in both dominant and non-dominant sides. Blood oxygen concentrations in brain from functional Near-infrared Spectroscopy (fNIRS) and surface electromyography (sEMG) signals in the biceps brachii (BIC) and triceps brachii (TRI) muscles were recorded simultaneously and compared during 80% and 20% of maximum voluntary contraction (MVC). Functional connectivity, effective connectivity, and graph theory indicators were used to measure information interaction in brain activity during motor tasks. The non-linear characteristics of sEMG signals, fuzzy approximate entropy (fApEn), were used to evaluate the signal complexity changes in motor tasks. Pearson correlation analysis was used to examine the correlation between brain network characteristic values and sEMG parameters under different task conditions. Results: The effective connectivity between brain regions in motor tasks in dominant side was significantly higher than that in non-dominant side under different contractions (p < 0.05). The results of graph theory analysis showed that the clustering coefficient and node-local efficiency of the contralateral motor cortex were significantly varied under different contractions (p < 0.01). fApEn and co-contraction index (CCI) of sEMG under 80% MVC condition were significantly higher than that under 20% MVC condition (p < 0.05). There was a significant positive correlation between the fApEn and the blood oxygen value in the contralateral brain regions in both dominant or non-dominant sides (p < 0.001). The node-local efficiency of the contralateral motor cortex in the dominant side was positively correlated with the fApEn of the EMG signals (p < 0.05). Conclusion: In this study, the mapping relationship between brain network related indicators and non-linear characteristic of sEMG in different motor tasks was verified. These findings provide evidence for further exploration of the interaction between the brain activity and the execution of motor tasks, and the parameters might be useful in evaluation of rehabilitation intervention.

Reaction dynamics of C(3P) + Si2(X $^{3}\Sigma ^-_g$ ) → Si(3P) + SiC(X 3Π) on a global CHIPR potential energy surface of the ground state Si2C(X 1A1)

ABSTRACT The dynamics of C(3P) + Si2(X $^{3}\Sigma ^-_g$ ) → Si(3P) + SiC(X 3Π) on its ground state Si2C(X 1A1) are of great significance in carbon-rich interstellar chemistry. Using the combined-hyperbolic-inverse-power-representation method, we construct the first global potential energy surface (PES) for the electronic ground state Si2C(X 1A1) based on a total of 4080 ab initio energy points, which are obtained at the Davidson-corrected internally contracted multireference configuration interaction level of theory. The topographical features of the newly constructed PES are examined in detail and show good agreement with previous theoretical and experimental studies. Finally, we investigate the C(3P) + Si2(X $^{3}\Sigma ^-_g$ ) → Si(3P) + SiC(X 3Π) reaction using the quasi-classical trajectory and time-dependent wave packet calculations, yielding reasonable integral cross sections and rate constants, which are expected to be useful for astrochemical modelling in carbon-rich interstellar environments.

Acute adaptation of central and peripheral motor unit features to exercise-induced fatigue differs with concentric and eccentric loading.

What is the central question of this study? Conflicting evidence exists on motor unit (MU) firing rate in response to exercise-induced fatigue, possibly due to the contraction modality used: Do MU properties adapt similarly following concentric and eccentric loading? What is the main finding and its importance? MU firing rate increased following eccentric loading only despite a decline in absolute force. Force steadiness deteriorated following both loading methods. Central and peripheral MU features are altered in a contraction type-dependant manner, which is an important consideration for training interventions. Force output of muscle is partly mediated by the adjustment of motor unit (MU) firing rate (FR). Disparities in MU features in response to fatigue may be influenced by contraction type, as concentric (CON) and eccentric (ECC) contractions demand variable amounts of neural input, which alters the response to fatigue. This study aimed to determine the effects of fatigue following CON and ECC loading on MU features of the vastus lateralis (VL). High-density surface (HD-sEMG) and intramuscular (iEMG) electromyography were used to record MU potentials (MUPs) from bilateral VLs of 12 young volunteers (six females) during sustained isometric contractions at 25% and 40% of the maximum voluntary contraction (MVC), before and after completing CON and ECC weighted stepping exercise. Multi-level mixed effects linear regression models were performed with significance assumed as P<0.05. MVC decreased in both CON and ECC legs post-exercise (P<0.0001), as did force steadiness at both 25% and 40% MVC (P<0.004). MU FR increased in ECC at both contraction levels (P<0.001) but did not change in CON. FR variability increased in both legs at 25% and 40% MVC following fatigue (P<0.01). From iEMG measures at 25% MVC, MUP shape did not change (P>0.1) but neuromuscular junction transmission instability increased in both legs (P<0.04), and markers of fibre membrane excitability increased following CON only (P=0.018). These data demonstrate that central and peripheral MU features are altered following exercise-induced fatigue and differ according to exercise modality. This is important when considering interventional strategies targeting MU function.

30 Years of Experience in Musculocutaneous Latissimus Dorsi Flap Phalloplasty with Reinnervation: Optimal Principles.

We performed a retrospective review of patients who underwent shaft-only, two-stage or one-stage latissimus dorsi flap phalloplasty with or without reinnervation at a single institution from 1991 through 2020. Patients with a minimum of 1 year of follow-up were included. Data on the patient's demographics, the procedure, and the results of the operation were maintained. In total, 592 latissimus dorsi flap phalloplasties were performed during the entire study period. Of the phalloplasties, 494 (83.5%) were performed for gender-affirming surgery, of which 470 were performed for transgender patients and 24 for intersex patients. Twenty-five patients (4.2%) had congenital malformations, 17 (2.9%) had oncologic resections, and 56 had posttraumatic loss (9.5%). Latissimus dorsi flap total phalloplasty with reinnervation is currently one of the few methods that can solve not only an aesthetic problem, but also a functional one without the use of an endoprosthesis if the level of reinnervation and muscle contraction is sufficient.

Comparison of myo-electrical control methods: From muscle energy consumption to mechanical speed output

In this study, an answer was sought to the question of how the person's muscle energy consumption is related to the prosthesis average speed outputs obtained through a comparison of the three control methods normally used in commercial prosthetics. Data sets for the sEMG (Surface Electromyography) were generated using commercial muscle tester for different contraction levels of wrist extension motion. These signals were then conditioned to get valuable information for moving the motor using comparable control methods. A customized experimental setup was established for the comparison of these control methods.For comparison purposes, the desired response from the prosthetic hand was considered as the ability to vary the speed constantly and uniformly from a minimum (zero) to a maximum value. Each sEMG signal was applied to the controllers, and the controller outputs were applied to the prosthetic hand. Measured prosthetic hand speeds were compared to the desired motion. To do this, parameters such as the error from the desired speed, total energy transferred to the motor of the prosthesis, and average speed were compared.The results indicate that the three control methods map the same sEMG energies to a different range of control signal energies and consequently, to different speed ranges. It has been shown that no control method alone can cover the all-speed range. This study suggests that new control methods (such as hybrid control methods) should be developed that better cover all speed ranges.

Motor Unit Number Estimation in Spastic Biceps Brachii Muscles of Chronic Stroke Survivors Before and After BoNT Injection.

The study aims to characterize the motor unit (MU) loss in spastic biceps brachii muscle (BBM) of chronic stroke survivors before and after botulinum neurotoxin (BoNT) injection. High-density weighted average (HDWA) motor unit number estimation (MUNE) was employed to estimate the number of functioning motor units of BBMs of eight chronic stroke survivors 1-week before (1st visit) and 3-week after (2nd visit) BoNT injection based on the surface electromyography (sEMG) signals recorded during voluntary contraction and supramaximal electrical stimulation. Significant lower MUNE was estimated from the spastic BBMs compared to the non-spastic MUNEs during two visits. A surprisingly higher MUNE was obtained from the spastic side during the 2nd visit after BoNT injection. The HDWA MUNE technique can be employed to characterize the motor unit loss in spastic muscle caused by upper motor neuro lesions at contraction level up to 30% MVC, but may fail to detect the MU loss caused by the chemodenervation effect of BoNT due to the non-uniform denervation of small and large size MUs. This study presents the first effort to evaluate the applicability of HDWA MUNE technique to characterize the MU loss in the spastic muscle following stroke and the subsequent BoNT injection for the treatment of post-stroke spasticity. The finding of this study suggests that HDWA MUNE can be a sensitive approach to detect the MU loss in spastic muscles after stroke, but the large inter-subject MUNE variability after the BoNT injection should be interpreted with caution.

Effects of a Soluble Guanylate Cyclase Stimulator Riociguat on Contractility of Isolated Pulmonary Artery and Hemodynamics of U46619-Induced Pulmonary Hypertension in Dogs

Soluble guanylate cyclase (sGC) stimulator riociguat is a relatively novel therapeutic agent for pulmonary hypertension (PH) in human medicine. Riociguat induces endothelium-independent pulmonary artery (PA) relaxation by directly activating the sGC-cyclic guanosine-3',5'-monophosphate (cGMP) pathway in muscle cells. Although riociguat may be effective in the treatment of dogs with refractory PH, basic studies on its clinical application in veterinary medicine are lacking. The present study aimed to explore the effects of riociguat on the contractility of an isolated canine PA and the hemodynamics of dogs with acute PH. In an isolated endothelium-denuded canine PA, the effects of riociguat on endothelin (ET)-1-induced contraction and cGMP levels were investigated using the Magnus method and ELISA, respectively. The effect of riociguat on the hemodynamics of the thromboxane A2 analog U46619-induced PH model dog was examined by invasive catheterization. Riociguat increased cGMP levels and reduced ET-1-induced contraction of the isolated PA. Riociguat inhibited the U46619-induced elevation of PA pressure and pulmonary vascular resistance and increased cardiac output, but it had no effect on basal systemic blood pressure. These results demonstrate for the first time that riociguat can inhibit the elevation of PA pressure through PA relaxation via an endothelium-independent increase in cGMP in dogs with PH.

Relevant criteria for selecting project delivery methods in sustainable construction

There is a lag in incorporating sustainability in core project management practices such as the selection of project delivery methods. Available literature focuses on traditional selection criteria of project delivery methods. These criteria, while important, may not address the challenges associated with sustainable construction projects’ delivery. There is a need to develop relevant selection criteria that increase the success rate of sustainable construction projects. This paper bridges this gap by identifying relevant criteria and modelling the correlation between the selection criteria exogenous variables and their corresponding latent variables as well as evaluating the impact of the relevant selection criteria on the success of sustainable construction projects. A partial least square structural equation model (PLS-SEM) is developed based on a survey that was administered to construction professionals in the UAE to collect their perceptions on the significance of the selection criteria. 110 responses were collected using a snowball sampling technique and the results revealed that all of the selection criteria proved to be significant. These include: level of integration, green team, green contract, green liability and technology. It is recommended to prioritize the level of integration, green team and green liability criteria groups for the PDM selection in sustainable construction projects.

Remuneration level of security guards from Samburu community working in Nairobi

This study investigated the remuneration level of security guards from Samburu Community working in Nairobi. The study adopted, as its theoretical framework, the Interests Theory of human rights as described by Raz. In examining these issues, the study looked at the following indicators, which provided evidence for granting or non-granting of employee rights: shelter, diet and investments made by the employees; existence of job contracts, insurance cover, retirement benefit plan and health cover; membership to a trade union; promotion at work and salary increment; and the nature of equipment and training for the job. The study involved all security guards from the Samburu community working in Nairobi as the population of study and individual security guards as the unit of analysis. Five areas of the city, that is, Westlands/Kabete, Lavington/Kangemi/Waithaka/Muthaiga/Thika Road, Karen/Lang’ata, South C/South B and Embakasi, were marked out as the places from which the study sample was taken. The study adopted a survey design, and data was collected through questionnaires, which were applied to 200 security guards who had been randomly selected from 5 administrative clusters in Nairobi. The findings indicated that security guards were poorly remunerated. It recommended that the government of Kenya enforce a minimum salary of at least at the level of maximum un-taxable income and proper job contraction for security guards.

Remuneration level of security guards from Samburu community working in Nairobi

This study investigated the remuneration level of security guards from Samburu Community working in Nairobi. The study adopted, as its theoretical framework, the Interests Theory of human rights as described by Raz. In examining these issues, the study looked at the following indicators, which provided evidence for granting or non-granting of employee rights: shelter, diet and investments made by the employees; existence of job contracts, insurance cover, retirement benefit plan and health cover; membership to a trade union; promotion at work and salary increment; and the nature of equipment and training for the job. The study involved all security guards from the Samburu community working in Nairobi as the population of study and individual security guards as the unit of analysis. Five areas of the city, that is, Westlands/Kabete, Lavington/Kangemi/Waithaka/Muthaiga/Thika Road, Karen/Lang’ata, South C/South B and Embakasi, were marked out as the places from which the study sample was taken. The study adopted a survey design, and data was collected through questionnaires, which were applied to 200 security guards who had been randomly selected from 5 administrative clusters in Nairobi. The findings indicated that security guards were poorly remunerated. It recommended that the government of Kenya enforce a minimum salary of at least at the level of maximum un-taxable income and proper job contraction for security guards.