Phasic Contractions Research Articles

Comparison of a semi-automatic strain analysis of left heart with manual myocardial tracing in speckle-tracking echocardiography

Purpose. To compare a semi-automatic strain analysis of the left ventricle and left atrium with a manual method in speckle-tracking echocardiography.Materials and methods. A strain of left ventricle and left atrium was assessed in 110 patients by two methods: manual (Q-Analysis) and semi-automatic (AutoStrain). The following parameters were evaluated: LV global longitudinal strain (LV GLS), LA longitudinal strain during the reservoir phase (LASr), LA longitudinal strain during the conduit phase (LAScd), and LA longitudinal strain during the contraction phase (LASct).Results. The ROI correction was carried out significantly more often with the semi-automatic method of measuring LV GLS than with manual (40.1% vs. 16.4%, p < 0.05). There were significant differences in LV GLS average values, LASr values, and LAScd values obtained by the semi-automatic and manual methods. LV GLS average values obtained by the semi-automatic method were lower (18.8 ± 2.8% vs. 20.0 ± 3.1%, p < 0.001), and the values of LASr and LAScd obtained by the semi-automatic method were higher (LASr 31.6 ± 9.8% vs. 30.3 ± 10.8%, p = 0.038; LAScd 17.1 ± 7.1% vs. 15.4 ± 6.8%, p < 0.001) than in manual. Semi-automatic method takes more time for LV strain analysis and less time for LA strain analysis than manual method.Conclusion. The semi-automatic method of LV and LA strain evaluation showed higher reproducibility compared with the manual method. With the semi-automatic method, the values of the LV GLS were lower, and the correction of ROI was required more often and took more time than with manual. The semi-automatic method of LA strain evaluation was characterized by higher values in the reservoir and conduit phases and required less time compared to the manual method. The LA longitudinal strain in the reservoir phase showed the highest values of reproducibility compared to other LA strain paremeters.

Dynamic phenotypic shifts and M2 receptor downregulation in bladder smooth muscle cells induced by mirabegron.

Mirabegron is available for treatment of overactive bladder (OAB). However, mechanisms underlying symptom improvements and long-term effects on bladder smooth muscle cells are uncertain. Contractility and growth of bladder smooth muscle contribute to OAB, and depend on smooth muscle phenotypes, and on muscarinic receptor expression. Here, we examined prolonged exposure to mirabegron (20-48h) on phenotype markers, muscarinic receptor expression, and phenotype-dependent functions in human bladder smooth muscle cells (hBSMC). Expression of markers for contractile (calponin, MYH11) and proliferative (MYH10, vimentin) phenotypes, proliferation (Ki-67), and of muscarinic receptors were assessed by RT-PCR. Proliferation, viability, actin organization and contractions in cultured hBSMC were examined by EdU, CCK-8, phalloidin staining and matrix contraction assays. Calponin-1 mRNA decreased with 100nM and 150nM mirabegron applied for 20h (0.56-0.6 fold of controls). Decreases were resistant to the β3-AR antagonist L-748,337 (0.34-0.55 fold, 100-150nM, 20h). After 40h, decreases occured in the presence of L-748,337, but not without L-748,337. MYH11 mRNA increased with 150nM mirabegron (40h, 1.9 fold). This was partly preserved with L-748,337, but not observed after 20h mirabegron exposure. Vimentin mRNA reduced with 150nM mirabegron after 20h, but not after 40h, with and without L-748,337 (0.71-0.63 fold). MYH10 mRNA expression remained unaffected by mirabegron. Exposure to 150nM mirabegron increased Ki-67 mRNA after 20h in the presence of, but not without L-748,337, and after 40h without, but not with L-748,337. Proliferation rates and actin organization were stable with 50-150nM mirabegron (24h, 48h). Viability increased significantly after mirabegron exposure for 20h, and by trend after 40h, which was fully sensitive to L-748,337. M2 mRNA was reduced by 20h mirabegron, which was resistant to L-748,337. Carbachol (3µM) enhanced time-dependent contractions of hBSMC, which was inhibited by mirabegron (150nM) in late phases (24h), but not in early phases of contractions. Conclusion: Mirabegron induces dynamic phenotype alterations and M2 downregulation in hBSMC, which is paralleled by time-shifted anticontractile effects. Phenotype transitions may be involved in improvements of storage symptoms in OAB by mirabegron.

Reduction in motor error by presenting subthreshold somatosensory information during visuomotor tracking tasks

Weak sensory noise acts on the nervous system and promotes sensory and motor functions. This phenomenon is called stochastic resonance and is expected to be applied for improving biological functions. This study investigated the effect of electrical stimulation on grip force adjustment ability. The coefficient of variation and absolute motor error in grip force was measured during a visuomotor tracking task under different intensities of somatosensory noise. Depending on the style of force exertion, the grip movement used in the visuomotor tracking task consisted of force generation (FG), force relaxation (FR), and constant contraction (Constant) phases. The subthreshold condition resulted in significantly lower coefficient of variation in the Constant phase and motor errors in the FG and Constant phases than the no-noise condition. However, the differences among the other conditions were insignificant. Additionally, we examined the correlation between the motor error in the condition without electrical stimulation and the change in motor error induced by subthreshold electrical stimulation. Significant negative correlations were observed in all FG, FR, and Constant phases. These results indicated that somatosensory noise had a strong effect on subjects with large motor errors and enhanced the grip force adjustment ability. By contrast, subjects with small motor errors had weak improvement in motor control. Although the effect of subthreshold noise varies depending on the individual differences, stochastic resonance is effective in improving motor control ability.

Impact Of Business Cycle And Revenue Diversification On Capital Buffer And Bank Risk: Empirical Studies From Asean Countries

The purpose of this research is to examine how business cycle and income diversification affect on capital buffer and banking risk in ASEAN from 2020 to 2022. The samples used in this research were 93 banks taken using purposive sampling techniques in the Philippines, Indonesia, Malaysia, Singapore, Thailand, and Vietnam. By using 2-SLS on panel data to analyze the data in the model being built. This research found that when the economy is in a contraction phase, banks will increase capital buffers. Then, if the bank’s revenue streams become more diversified, this could potentially weaken its capital buffer reserves and decrease risk levels in the banking sector. Meanwhile, expansionary business cycles and revenue diversification provide in reducing bank risk to encourage economic growth. In addition, the correlation between the level adjustment of capital buffer and bank risk confirms a positive impact.

Enhancing the diagnostic yield of esophageal manometry using distension-contraction plots of peristalsis and artificial intelligence.

Our prior study reveals that the distension-contraction profiles using high-resolution manometry impedance recordings can distinguish patients with dysphagia symptom but normal esophageal function testing ("functional dysphagia") from control subjects. The aim of this study was to determine the diagnostic value of the recording protocol used in our prior studies (10-mL swallows with subjects in the Trendelenburg position) against the standard clinical protocol (5-mL swallows with subjects in the supine position). We used advanced machine learning techniques and robust metrics for classification purposes. Studies were performed on 30 healthy subjects and 30 patients with functional dysphagia. A custom-built software was used to extract the relevant distension-contraction features of esophageal peristalsis. Ensemble methods, i.e., gradient boost, support vector machines (SVMs), and logit boost, were used as the primary machine learning algorithms. Although the individual contraction features were marginally different between the two groups, the distension features of peristalsis were significantly different. The receiver operating characteristic (ROC) curve values for the standard recording protocol and the distension features ranged from 0.74 to 0.82; they were significantly better for the protocol used in our prior studies, ranging from 0.81 to 0.91. The ROC curve values using three machine learning algorithms were far superior for the distension than the contraction features of esophageal peristalsis, revealing a value of 0.95 for the SVM algorithm. Current patient classification for esophageal motility disorders, based on the contraction phase of peristalsis, ignores a large number of patients who have an abnormality in the distension phase of peristalsis. Distension-contraction plots should be the standard for assessing esophageal peristalsis in clinical practice.NEW & NOTEWORTHY Our findings underscore the superiority of distension features over contraction metrics in diagnosing esophageal dysfunctions. By leveraging state-of-the-art machine learning techniques, our study highlights the diagnostic potential of distension-contraction plots of peristalsis. Implementation of these plots could significantly enhance the accuracy of identifying patients with esophageal motor disorders, advocating for their adoption as the standard in clinical practice.

Effect of Business Cycle, Income Diversification, and Financial Ratios on Bank Risk in the ASEAN Region

Research Aims: This research aims to analyze the influence of the business cycle, income diversification, and financial ratios as proxied by profitability and liquidity on the level of banking risk adjustment in ASEAN in the 2020-2022 period. Design/methodology/approach: The research used a sample of 93 banks in the ASEAN region. Sample selection applied purposive sampling techniques based on certain criteria in the Philippines, Indonesia, Malaysia, Singapore, Thailand and Vietnam. The estimation technique used is the Ordinary Least Square method on panel data to analyze the model being built. Research Findings: Research shows that the relationship between the business cycle and bank risk is negative. This means that when the economy is in a contraction phase, bank risk will decrease and vice versa. Then, banks that diversify their income can reduce bank risk. On the other hand, the influence of profitability and liquidity has a negative effect, meaning that a high level of income accompanied by liquid bank assets has the potential to reduce the level of bank risk. Apart from that, there are several other aspects that banks need to pay attention to in anticipating emerging risks, including previous year's credit risk, business size, loan loss reserves, asset growth and financial freedom. Theoretical Contribution/Originality: The originality of the research lies in its comprehensive approach to analyzing the impact of business cycles, income diversification, and financial ratios on bank risk in the ASEAN region. The study's methodology, variables, and empirical evidence all contribute to its originality and relevance to the existing literature Keywords: Revenue Diversification, Liquidity, Profitability, Bank Risk, Business Cycle

Peningkatan Kreativitas Anak Di Panti Asuhan Bala Keselamatan (Salvation Army) Dengan Menggunakan Metode Casework

The purpose of this study is to improve the children's creativity at the Salvation Army Orphanage by using casework procedures. One tactic to stress problem solutions through organized and systematic social interventions is the casework technique. Children who took part in the program shown gains in their ability to think creatively, express themselves, and solve problems. Youngsters who had a natural desire to work and greater self-confidence also benefited. This journal's goal is to foster the imaginations and inventiveness of the kids at the Salvation Army Orphanage through the application of casework techniques, which span the engagement, intake, contract, assessment, planning, intervention, monitoring, evaluation, and termination phases.

Mapping the rat gastric slow-wave conduction pathway: bridging in vitro and in vivo methods, revealing a loosely coupled region in the distal stomach.

Rhythmic electrical events, termed slow waves, govern the timing and amplitude of phasic contractions of the gastric musculature. Extracellular multielectrode measurement of gastric slow waves can be a biomarker for phenotypes of motility dysfunction. However, a gastric slow-wave conduction pathway for the rat, a common animal model, is unestablished. In this study, the validity of extracellular recording was demonstrated in vitro with simultaneous intracellular and extracellular recordings and by pharmacological inhibition of slow waves. The conduction pathway was determined by in vivo extracellular recordings while considering the effect of motion. Slow-wave characteristics [means (SD)] varied regionally having higher amplitude in the antrum than the distal corpus [1.03 (0.12) mV vs. 0.75 (0.31) mV; n = 7; P = 0.025 paired t test] and faster propagation near the greater curvature than the lesser curvature [1.00 (0.14) mm·s-1 vs. 0.74 (0.14) mm·s-1; n = 9 GC, 7 LC; P = 0.003 unpaired t test]. Notably, in some subjects, separate wavefronts propagated near the lesser and greater curvatures with a loosely coupled region occurring in the area near the distal corpus midline at the interface of the two wavefronts. This region had either the greater or lesser curvature wavefront propagating through it in a time-varying manner. The conduction pattern suggests that slow waves in the rat stomach form annular wavefronts in the antrum and not the corpus. This study has implications for interpretation of the relationship between slow waves, the interstitial cells of Cajal network structure, smooth muscles, and gastric motility.NEW & NOTEWORTHY Mapping of rat gastric slow waves showed regional variations in their organization. In some subjects, separate wavefronts propagated near the lesser and greater curvatures with a loosely coupled region near the midline, between the wavefronts, having a varying slow-wave origin. Furthermore, simultaneous intracellular and extracellular recordings were concordant and independent of movement artifacts, indicating that extracellular recordings can be interpreted in terms of their intracellular counterparts when intracellular recording is not possible.

Ventricular Complementarity

Objective: Through research that we have carried out continuously in recent years and that includes the sequence of cardiac activation, anatomical studies, physiological experiences on the protodiastolic phase, ventricular septal interdependence, clinical and experimental research on negative intraventricular pressure and the suction mechanism, we reach the understanding of biventricular complementarity. Methods: The endo- and epicardial electrical activation sequence of the left ventricle has been studied using three-dimensional electroanatomical mapping with a Carto navigation that allows a three-dimensional anatomical representation, including five patients. Results: Diastole is divided into two phases. In the first, the ventricular volume does not vary, it is isometric, but with energy expenditure its morphology changes generating intraventricular negative pressure, call protodiastolic phase of myocardial contraction. During the second phase, ventricular filling occurs without energy expenditure. Conclusions: The asynchrony between the RV and LV cycles allows the interaction between expulsion and loading of each of them.

Pleistocene climate oscillations have shaped the expansion and contraction speciation model of the globose Eriosyce sect. Neoporteria cacti in Central Chile.

Pleistocene climatic oscillations, characterized by arid (interglacial) and pluvial (glacial) phases, have profoundly impacted the floras of Mediterranean climates. Our study investigates the hypothesis that these climatic extremes have promoted phases of range expansion and contraction in the Eriosyce sect. Neoporteria, resulting in pronounced genetic structuring and restricted gene flow. Utilizing nuclear microsatellite markers, we genotyped 251 individuals across 18 populations, encompassing all 14 species and one subspecies within the Eriosyce sect. Neoporteria. Additionally, Species Distribution Models (SDMs) were employed to reconstruct past (Last Interglacial, Last Glacial Maximum, Mid-Holocene) and current potential distribution patterns, aiming to delineate the climatic influences on species' range dynamics. The gene flow analysis disclosed disparate levels of genetic interchange among species, with marked restrictions observed between entities that are geographically or ecologically separated. Notably, E. subgibbosa from Hualpen emerged as genetically distinct, warranting its exclusion for clearer genetic clustering into north, central, and south clusters. The SDMs corroborated these findings, showing marked range expansions during warmer periods and contractions during colder times, indicating significant shifts in distribution patterns in response to climatic changes. Our findings emphasize the critical role of Pleistocene climatic fluctuations in driving the dynamic patterns of range expansions and contractions that have led to geographic isolation and speciation within the Eriosyce sect. Neoporteria. Even in the face of ongoing gene flow, these climate-driven processes have played a pivotal role in sculpting the species' genetic architecture and diversity. This study elucidates the complex interplay between climatic variability and evolutionary dynamics among Mediterranean cacti in central Chile, highlighting the necessity of considering historical climatic millenial oscillations in conservation and evolutionary biology studies.

Discovery of a Proto–White Dwarf with a Massive Unseen Companion

We report the discovery of SDSS J022932.28+713002.7, a nascent extremely low-mass (ELM) white dwarf (WD) orbiting a massive (>1 M ⊙ at 2σ confidence) companion with a period of 36 hr. We use a combination of spectroscopy, including data from the ongoing fifth-generation Sloan Digital Sky Survey (SDSS-V), and photometry to measure the stellar parameters of the primary pre-ELM WD. The lightcurve of the primary WD exhibits ellipsoidal variation, which we combine with radial velocity data and PHOEBE binary simulations to estimate the mass of the invisible companion. We find that the primary WD has mass M 1 = 0.18−0.02+0.02 M ⊙ and the unseen secondary has mass M 2 = 1.19−0.14+0.21 M ⊙. The mass of the companion suggests that it is most likely a near-Chandrasekhar-mass WD or a neutron star. It is likely that the system recently went through a Roche lobe overflow from the visible primary onto the invisible secondary. The dynamical configuration of the binary is consistent with the theoretical evolutionary tracks for such objects, and the primary is currently in its contraction phase. The measured orbital period puts this system on a stable evolutionary path which, within a few gigayears, will lead to a contracted ELM WD orbiting a massive compact companion.

Spectroscopic survey of faint planetary-nebula nuclei

We present spectroscopy of three hydrogen-deficient central stars of faint planetary nebulae, with effective temperatures (Teff) in excess of 100 000 K. The nucleus of RaMul 2 is a Population II Wolf-Rayet star of spectral type [WC], and the central stars of Abell 25 and StDr 138 are two new members of the PG1159 class. Our spectral analyses reveal that their atmospheres have a similar chemical composition. They are dominated by helium and carbon, which was probably caused by a late helium-shell flash. Coincidentally, the three stars have similar masses of about M = 0.53 M⊙ and hence form a post-asymptotic giant branch (AGB) evolutionary sequence of an initially early-K-type main sequence star with M = 0.8 M⊙. The central stars cover the period during which the luminosity fades from about 3000 to 250 L⊙ and the radius shrinks from about 0.15 to 0.03 R⊙. The concurrent increase of the surface gravity during this interval from log g = 5.8 to 7.2 causes the shutdown of the stellar wind from an initial mass-loss rate of log Ṁ/(M⊙ yr−1) = −6.4, as measured for the [WC] star. Along the contraction phase, we observe an increase in Teff from 112 000 K, marked by the [WC] star, to the maximum value of 140 000 K, and a subsequent cooling to 130 000 K, marked by the two PG1159 stars.

Urothelium-derived prostanoids enhance contractility of urinary bladder smooth muscle and stimulate bladder afferent nerve activity in the mouse.

The transitional epithelial cells (urothelium) that line the lumen of the urinary bladder form a barrier between potentially harmful pathogens, toxins, and other bladder contents and the inner layers of the bladder wall. The urothelium, however, is not simply a passive barrier, as it can produce signaling factors, such as ATP, nitric oxide, prostaglandins, and other prostanoids, that can modulate bladder function. We investigated whether substances produced by the urothelium could directly modulate the contractility of the underlying urinary bladder smooth muscle. Force was measured in isolated strips of mouse urinary bladder with the urothelium intact or denuded. Bladder strips developed spontaneous tone and phasic contractions. In urothelium-intact strips, basal tone, as well as the frequency and amplitude of phasic contractions, were 25%, 32%, and 338% higher than in urothelium-denuded strips, respectively. Basal tone and phasic contractility in urothelium-intact bladder strips were abolished by the cyclooxygenase (COX) inhibitor indomethacin (10 µM) or the voltage-dependent Ca2+ channel blocker diltiazem (50 µM), whereas blocking neuronal sodium channels with tetrodotoxin (1 µM) had no effect. These results suggest that prostanoids produced in the urothelium enhance smooth muscle tone and phasic contractions by activating voltage-dependent Ca2+ channels in the underlying bladder smooth muscle. We went on to demonstrate that blocking COX inhibits the generation of transient pressure events in isolated pressurized bladders and greatly attenuates the afferent nerve activity during bladder filling, suggesting that urothelial prostanoids may also play a role in sensory nerve signaling.NEW & NOTEWORTHY This paper provides evidence for the role of urothelial-derived prostanoids in maintaining tone in the urinary bladder during bladder filling, not only underscoring the role of the urothelium as more than a barrier but also contributing to active regulation of the urinary bladder. Furthermore, cyclooxygenase products greatly augment sensory nerve activity generated by bladder afferents during bladder filling and thus may play a role in perception of bladder fullness.

Interferometric Biosensor for High Sensitive Label-Free Recording of HiPS Cardiomyocytes Contraction in Vitro.

Heart disease remains a leading cause of global mortality, underscoring the need for advanced technologies to study cardiovascular diseases and develop effective treatments. We introduce an innovative interferometric biosensor for high-sensitivity and label-free recording of human induced pluripotent stem cell (hiPSC) cardiomyocyte contraction in vitro. Using an optical cavity, our device captures interference patterns caused by the contraction-induced displacement of a thin flexible membrane. First, we demonstrate the capability to quantify spontaneous contractions and discriminate between contraction and relaxation phases. We calculate a contraction-induced vertical membrane displacement close to 40 nm, which implies a traction stress of 34 ± 4 mN/mm2. Finally, we investigate the effects of a drug compound on contractility amplitude, revealing a significant reduction in contractile forces. The label-free and high-throughput nature of our biosensor may enhance drug screening processes and drug development for cardiac treatments. Our interferometric biosensor offers a novel approach for noninvasive and real-time assessment of cardiomyocyte contraction.

Analysis of pelvic floor muscle electromyography parameters in women with or without sexual dysfunction.

Background To investigate the differences in pelvic floor muscle (PFM) electromyography (EMG) parameters between women with or without sexual dysfunction (FSD) and their correlations. Methods Women who voluntarily participated in a questionnaire-based survey on sexual function and underwent PFM EMG in Weifang People's Hospital during the period from March 2021 to December 2021 were retrospectively enrolled. The female sexual (dys)function was measured using the Female Sexual Function Index. Glazer PFM EMG was performed using a Melander instrument (MLD A2 Deluxe). The differences in PFM EMG parameters between women with or without FSD were compared, and the relationships between PFM EMG parameters and FSD were analysed using multiple linear regression models. Results A total of 305 women were enrolled, with 163 in the FSD group and 142 in the non-FSD group. Comparisons of PFM EMG parameters between these two groups revealed that the FSD group had significantly higher peak EMG amplitude during the phasic (flick) contractions and shorter recovery latency during the tonic contractions than the non-FSD group (both P P Conclusions The results of the pelvic floor EMG in this study suggest that the pelvic floor muscles of women with FSD may be more susceptible to fatigue, and may have poorer coordination of their pelvic floor muscles.

Nitrergic inhibition of sympathetic arteriolar constrictions in the female rodent urethra.

During the urine storage phase, tonically contracting urethral musculature would have a higher energy consumption than bladder muscle that develops phasic contractions. However, ischaemic dysfunction is less prevalent in the urethra than in the bladder, suggesting that urethral vasculature has intrinsic properties ensuring an adequate blood supply. Diameter changes in rat or mouse urethral arterioles were measured using a video-tracking system. Intercellular Ca2+ dynamics in arteriolar smooth muscle (SMCs) and endothelial cells were visualised using NG2- and parvalbumin-GCaMP6 mice, respectively. Fluorescence immunohistochemistry was used to visualise the perivascular innervation. In rat urethral arterioles, sympathetic vasoconstrictions were predominantly suppressed by α,β-methylene ATP (10μM) but not prazosin (1μM). Tadalafil (100nM), a PDE5 inhibitor, diminished the vasoconstrictions in a manner reversed by N-ω-propyl-l-arginine hydrochloride (l-NPA, 1μM), a neuronal NO synthesis (nNOS) inhibitor. Vesicular acetylcholine transporter immunoreactive perivascular nerve fibres co-expressing nNOS were intertwined with tyrosine hydroxylase immunoreactive sympathetic nerve fibres. In phenylephrine (1μM) pre-constricted rat or mouse urethral arterioles, nerve-evoked vasodilatations or transient SMC Ca2+ reductions were largely diminished by l-nitroarginine (l-NA, 10μM), a broad-spectrum NOS inhibitor, but not by l-NPA. The CGRP receptor antagonist BIBN-4096 (1μM) shortened the vasodilatory responses, while atropine (1μM) abolished the l-NA-resistant transient vasodilatory responses. Nerve-evoked endothelial Ca2+ transients were abolished by atropine plus guanethidine (10μM), indicating its neurotransmitter origin and absence of non-adrenergic non-cholinergic endothelial NO release. In urethral arterioles, NO released from parasympathetic nerves counteracts sympathetic vasoconstrictions pre- and post-synaptically to restrict arteriolar contractility. KEY POINTS: Despite a higher energy consumption of the urethral musculature than the bladder detrusor muscle, ischaemic dysfunction of the urethra is less prevalent than that of the bladder. In the urethral arterioles, sympathetic vasoconstrictions are predominately mediated by ATP, not noradrenaline. NO released from parasympathetic nerves counteracts sympathetic vasoconstrictions by its pre-synaptic inhibition of sympathetic transmission as well as post-synaptic arteriolar smooth muscle relaxation. Acetylcholine released from parasympathetic nerves contributes to endothelium-dependent, transient vasodilatations, while CGRP released from sensory nerves prolongs NO-mediated vasodilatations. PDE5 inhibitors could be beneficial to maintain and/or improve urethral blood supply and in turn the volume and contractility of urethral musculature.

Helical Actuator–Driven Inchworm Robot Design and Prototype

Abstract Bio-inspired robots provide solutions in many applications. Robots that can traverse and transport materials through confined areas are useful in disaster response, mining, mapping, and tunneling. The proposed robot is an inchworm-inspired robot that contracts and expands its body segments to move. It has spiky feet that are angled to only allow each foot to slide forward. It has a small frontal area compared to its length, and this allows it to travel through tight gaps or tunnels. Each segment uses two helical actuators as prismatic linkages to drive both forward movement and turning movement. These helical actuators transform the rotation of stepper motors into linear motion. Many linkage configurations were considered in designing this robot, and one without continuous singularities was selected. The robot stride consists of an extension phase and a contraction phase. In each phase, one foot is stationary, and one foot is moving. When each of the feet is in motion, the ground reaction force is assumed to be zero. The motion planning of the robot is designed so that the velocity and acceleration of each of the robot's rigid bodies are zero at the beginning and end of each movement phase. A 3D-printed prototype of the robot has been manufactured, and initial testing has shown that the foot spike design successfully allows the inchworm to shuffle forward. Testing the turning capabilities of this robot is ongoing.

Bouncing Cosmology in f(R,G)$f(R,\mathcal {G})$ Gravity with Thermodynamic Analysis

AbstractThe evolution of the universe in a modified gravity theory that includes the terms Ricci scalar () and the Gauss‐Bonnet invariant () is studied. The function is obtained using the e‐folding number and reconstruction technique by assuming an appropriate parameterization of the scale factor . In this model, the various cosmological parameters are analyzed to explicate the bouncing scenario of the universe with the help of the contraction and expansion phases of the universe before and after the bouncing point of the model, respectively. A violation of the null energy condition is found. Additionally, the ghost condensate nature of the model in the neighborhood of the bouncing point () is seen. Furthermore, the deceleration parameter is not defined at the bouncing point, i.e., at and approaches a finite value in later times (). Finally, the evolution of the Hawking temperature and the validity of the second law of thermodynamics in the bouncing scenario of our model are discussed.

Open air X-ray diffractometer for crystallography, compression, contraction, and structural phase transitions with variable temperature capabilities

It is a fact that materials contract or expand by changing their temperature. In a certain temperature range, the distance between atoms changes linearly in some materials whereas it changes non-linearly in other materials. X-ray diffraction (XRD) is one of the popular techniques used for understanding the crystal structure of these materials. However, XRD is mostly carried in open air at room temperature or require very expensive high vacuum set-ups and expensive temperature controllers for low temperature studies. Here we propose a design of a variable temperature X-ray diffractometer that can operate in dual modes: heating and cooling in open air. The proposed diffractometer has been used for studying structural phase transition in chromium nitride thin films. The results demonstrated not only the effectiveness of our proposed setup but also its applicability in advancing our understanding of complex material behaviors.•A new design of a variable temperature X-ray diffractometer has been introduced in this paper, which can be used for acquiring XRD data while heating or cooling samples in open air.•As a proof of concept, the newly designed variable temperature X-ray diffractometer is used for studying structural phase transition in CrN thin films.

Commonality and heterogeneity of pacemaker mechanisms in the male reproductive organs.

During emission, the first phase of ejaculation, smooth muscle in organs of the male reproductive tract (MRT) vigorously contract upon sympathetic nerve excitation to expel semen consisting of sperm and seminal plasma. During inter-ejaculation phases, the epididymis, seminal vesicles and prostate undergo spontaneous phasic contractions (SPCs), this transporting and maintaining the quality of sperm and seminal plasma. Recent studies have revealed platelet-derived growth factor receptor α-expressing (PDGFRα+) subepithelial interstitial cells in seminal vesicles subserve the role of pacemaker cells that electrically drive SPCs in this organ. PDGFRα+ smooth muscle cells in the epididymis also appear to function as pacemaker cells implicating PDGFRα as a potential signature molecule in MRT pacemaking. The dominant mechanism driving pacemaking in these organs is the cytosolic Ca2+ oscillator. This operates through entrainment of the release-refill cycle of Ca2+ stores, the released Ca2+ ions opening Ca2+-activated chloride channels, including in some cases ANO1 (TMEM16A), with the resultant pacemaker potential activating L-type voltage-dependent Ca2+ channels in the smooth muscle causing contraction (viz. SPCs). A second pacemaker mechanism, namely the membrane oscillator also has a role in specific cases. Further investigations into the commonality and heterogeneity of MRT pacemakers will open an avenue for understanding the pathogenesis of male infertility associated with deterioration of seminal plasma.