Phasic Contractions Research Articles

Left atrial stiffness index in patients with cryptogenic ischemic stroke: a clue of atrial fibrillation?

Abstract Introduction About 25% of cryptogenic ischemic stroke are due to undiagnosed atrial fibrillation. New echocardiographic markers derived from left atrial strain analysis could be useful to early identify patients candidates to oral anticoagulation. Purpose Aim of our study was to investigate the relationship between left atrial strain parameters assessed by speckle tracking echocardiography (STE) and the new documentation of atrial fibrillation at follow-up in patients admitted for acute cryptogenic ischemic stroke. Methods From 2020 to 2023 consecutive patients admitted to Stroke Unit of our Hospital for cryptogenic ischemic stroke undergoing loop-recorder implantation were retrospectively enrolled in our study. Main exclusion criteria were previous diagnosis of atrial fibrillation and poor image quality. All patients underwent full echocardiographic examination, including left atrial strain analysis with STE by dedicated software. Results Sixty-nine patients were finally selected, divided in patients with and without atrial fibrillation at follow-up (26 and 43 pts, respectively). No clinically significant differences were found between the two groups at baseline. Analysing echocardiographic parameters, significant differences were found in patients with and without diagnosis of atrial fibrillation at follow-up, respectively, with regard to left atrial volume index (LAVi, 44.26 ± 10.58 vs 34.54 ± 11.03 ml/m2, p 0.005), peak atrial longitudinal strain of reservoir phase (PALSr 19.50 ± 8.48 vs 26.22 ± 9.11%, p 0.01) and contraction phase (PALSct 5.70 (0; 20.92) vs 11.23 (5.98; 16), p 0.017). Left atrial stiffness index was defined as the ratio between E/E’ (expression of left ventricular filling pressures) and PALSr. Using a cut-point of 0.55, identified with ROC analysis, a significant difference was found between the two groups (10/26 (38.4%) vs 4/43 (9.3%), p 0.002). Among all these parameters, at the multivariate logistic regression analysis only left atrial stiffness index showed a trend to the significance (p 0.06). Conclusions Left atrial strain analysis can be useful to better select patients with cryptogenic stroke who need loop-recorder implantation and a closer follow-up to prompt recognize atrial fibrillation. In particular, Left atrial stiffness index seems to be the most useful parameter to stratify patients at higher risk of atrial fibrillation.

Left atrial stiffness index by three-dimensional speckle tracking echocardiography:association with exercise capacity in hypertension-related heart failure with preserved ejection fraction patients

Abstract Objective The purpose of this study was to analyze the characteristics of left atrial function and its utility compared with exercise E/e’(Ex-E/e’). To explore the diagnostic value of three dimensional left atrial stiffness index(3D-LASI) in predicting exercise ability in hypertension(HT) and hypertension-related heart failure with preserved ejection fraction (HT-HFpEF) patients. Methods The study population consisted of 62 healthy subjects and 163 patients with hypertension (112 patients in the simple HT group and 51 patients in the HT-HFpEF group) from July 1, 2022 to July 31, 2023. Standard two dimensional and three dimensional ultrasonic images were collected and analyzed, especially the 3D left atrial function were evaluated.Treadmill exercise stress test was performed, and hemodynamic parameters were recorded.To evaluate the diagnostic value of 3D-LASI (E/e’/LASr and E/e’/LASr-c) in HT and HT-HFpEF patients’ exercise capacity. Results Compared with the healthy subjects, the HT group’s left atrial volume of different phase increased and strain value decreased (p < 0.05). In HT-HFpEF group, the longitudinal strain of reserve phase(LASr),circumferential strain of reserve and contraction phase(LASr-c,LASct-c) furtherd decreased. The E/e’/LASr and E/e’/LASr-c were significantly correlated with METs (r=-0.498, p < 0.001;r=-0.412, p < 0.001) , through multiple regression model analysis, E/e’/LASr and E/e’/LASr-c remained independent predictors of metabolic equivalents(METs) .The E/e’/LASr and E/e’/LASr-c(AUC, 0.845;AUC,0.809) demonstrated great value for identify HT-HFpEF with reduced exercise capacity by receiver operating characteristic curves and E/e’/LASr had similar diagnostic efficacy compared with Ex-E/e’(AUC: 0.845 vs 0.876, p=0.239 dron test)). Conclusion The left atrial stiffness in HT-HFpEF patients can be evaluated by 3D speckle tracking technology, including rapid acquisition of different phase parameters.The E/e’/LASr and E/e’/LASr -c as indicators of atrioventricular compliance plays key role in maintaining left atrial function, and E/e’/LASr is an independent predictor of exercise ability and with similar diagnostic value to Ex-E/e’ in HT-HFpEF patients. correlation analysis heat map ROC for identify HT-HFpEF

A new vendor-independent software tool allows for reliable measurement of left ventricular, right ventricular and left atrial global longitudinal strain

Abstract Introduction Speckle tracking echocardiography (STE) has become an essential clinical tool. However, its use in everyday practice remains cumbersome due to differences between vendor-specific measurement packages and a lack of compatibility. Vendor-independent software tools can overcome these limitations and allow for more widespread use of STE. Aim To assess the feasibility and accuracy of a new vendor-independent software (VIS) tool for measuring left and right ventricular, as well as left atrial global longitudinal strain using a well-established vendor-specific software (VSS) package as a reference. Methods 110 patients (60 male, mean age 65 ±12,5 years) with various cardiovascular pathologies who underwent transthoracic echocardiography in the cardiology department were included in the study group. All acquired images were sent to an external workstation, where they were analyzed offline using a vendor-specific measurement package and a new vendor-independent software tool. Patients with suboptimal image quality of any myocardial segment were excluded from the study group. The analysis included measurements of left ventricular global longitudinal strain (LV GLS) based on three apical views, as well as right ventricular global longitudinal strain (RV GLS) and right ventricular free wall strain (RV FWS) based on apical four-chamber RV-focused view. Left atrial strain (LAS) measurements were based on a four – and two-chamber apical view and the three phases of the atrial function were analyzed. Results Due to suboptimal image quality, 31 and 36 patients were excluded from the LV and RV analysis groups, respectively. We observed strong correlations between measurement results obtained using VS and VI software tools for the LV (r=0,888, p<0,0001) and RV global strain (r=0,807, p<0,0001) and RV FWS (r=0,836, p<0,0001). Mean LV GLS measured by VIS and VSS were -15,3±3,4% and -14,4±3,5%, respectively (p=NS). Mean RV GLS measured by VIS and VSS were -16,5±4,4% and -17,4±5%, respectively (p=0,NS). Mean RV FWS obtained with VIS and VSS were -18,7±5,5% and -21±6,7%, respectively (p=NS). 51 patients (32 male, mean age 63,5±12 years) had feasible image quality for calculating LAS. In this group, strong correlations between the measurement results using VS and VI software tools were observed for the reservoir (r=0,8956 p<0,0001), conduit (r=0,8168, p<0,0001), and contraction (r=0,8759 p<0,0001) phases. The mean reservoir strain measured by VIS and VSS were 23,04±7,99% and 21,7±7,7%, respectively (p=NS). Mean conduit strain measured by VIS and VSS were 10,07±5,02% and 8,71±3,85%, respectively (p=NS). The mean contraction strains obtained with VIS and VSS were 13,01±5,42% and 13,99±5,49%, respectively (p=NS). Conclusion A new vendor-independent software tool, allows for reliable measurement of left and right ventricular global longitudinal strain, as well as left atrial strain.

Single-Cell Proteomics Uncovers Dual Traits of Dermal Sheath Cells in Wound Repair.

Wound healing is a dynamic process involving multiple cell types and signaling pathways. Dermal sheath cells (DSCs), residing surrounding hair follicles, play a critical role in tissue repair, yet their regulatory mechanisms remain unclear. This study used single-cell proteomics with the AcanCreER;R26LSL-tdTomato-DTR mouse model to explore DSC function across different healing stages. All animal procedures were conducted in accordance with the Animal Research: Reporting of In Vivo Experiments guidelines. Gene set enrichment analysis (GSEA) and temporal clustering (Mfuzz) were employed to reveal dynamic functional shifts. GSEA identified enriched gene sets related to interferon-gamma response, inflammatory response, ultraviolet response, myogenesis, and xenobiotic metabolism. Temporal clustering revealed eight distinct clusters: clusters associated with the early contracting and proliferative phases were linked to metabolic activation and oxidative stress, while clusters from the later remodeling phase emphasized extracellular matrix remodeling and structural reorganization. The dynamic expression of epithelial-mesenchymal transition-related genes and keratins supported DSCs' dual epithelial and mesenchymal traits. Additionally, keratins, collagens, integrins, and actin proteins emerged as promising markers or signature molecules for DSCs. This study reveals DSCs' dual traits during wound repair, providing a basis for therapies to enhance healing.

Population Pharmacokinetics of Orvacabtagene Autoleucel, an Autologous BCMA-Directed Chimeric Antigen Receptor T-Cell Product, in Patients with Relapsed/Refractory Multiple Myeloma.

Orvacabtagene autoleucel (orva-cel; JCARH125), a CAR T-cell therapy targeting B-cell maturation antigen (BCMA), was evaluated in relapsed/refractory multiple myeloma (RRMM) patients in the EVOLVE phase 1/2 study (NCT03430011). We applied a modified piecewise model to characterize orva-cel transgene kinetics and assessed the impact of various covariates on its pharmacokinetics (PK). The population PK analysis included 159 patients from the EVOLVE study. Traditional piecewise models, employing a first-order expansion rate with or without lag time followed by a bi-exponential contraction phase, were compared with a modified model incorporating a cell number-dependent expansion phase aligned with cellular physiology. Covariates assessed encompassed baseline demographics, dose levels (50 to 600 × 106 CD3+ CAR+ T cells), prior/concomitant medications, baseline disease burden, and anti-therapeutic antibody (ATA) status. Traditional piecewise models failed to accurately describe maximum orva-cel transgene level (Cmax) and underestimated the time to Cmax (Tmax). Our modified model incorporating a cell number-dependent expansion rate outperformed traditional models by 1) more accurately capturing the cellular expansion phase, and 2) yielding a Tmax that closely matches observed values. Additionally, dose level, percentage of plasma cells in bone marrow, and treatment-induced ATA were identified as statistically significant covariates and associated with orva-cel expansion and/or persistence. Orva-cel PK were adequately described by the modified piecewise model incorporating a cell number-dependent expansion phase, which aligns closely with T cell biology.

KV7 channels modulate tension and calcium signalling in mouse corpus cavernosum.

Adrenergic stimulation induces contractions in the corpus cavernosum smooth muscle (CCSM) that are important in maintaining penile flaccidity. The aim of this study was to investigate the role of KV7 channels in regulating contractions and their underlying Ca2+ signals in mouse CCSM. Quantitative PCR revealed transcriptional expression of KCNQ1 and KCNQ3-5 genes in whole CCSM, with KCNQ5 as the most highly transcribed KV7 encoding gene. Immunocytochemistry in single CCSM myocytes confirmed expression of KV7.5 protein. CCSM crura developed spontaneous phasic contractions in vitro that were inhibited by retigabine (RTG), a KV7 channel opener, and potentiated by XE-991 a KV7 channel blocker. The contractions were also blocked by nifedipine, confirming that they were dependent upon Ca2+ influx via L-type Ca2+ channels. Similarly, PE (0.3 μM) evoked phasic contractions that were inhibited and enhanced by RTG and XE-991, respectively. When a range of concentrations of PE (0.3 μM - 30 μM) was examined, both phasic and tonic contractions were observed, with phasic predominating at lower concentrations and tonic at higher concentrations. RTG inhibited only the phasic contractions suggesting that these were dependent upon membrane potential, but tonic contractions were not. In single dispersed CCSM myocytes, spontaneous Ca2+ waves and Ca2+ waves induced by PE (0.1 μM) were inhibited by RTG or nifedipine and enhanced by XE-991. PE (10 μM) also induced Ca2+ waves but, similar to tonic contractions, these were resistant to inhibition with RTG or nifedipine. These findings have implications for targeting KV7 channels in treatment of erectile dysfunction (ED).

Thymol and Carvacrol as Potential Tocolytic and Anti-inflammatory Agents in Pregnant Rat Uterus.

This work aimed to evaluate the anti-inflammatory and myorelaxant effect of thymol (TM) and carvacrol (CAR) in the pregnant rat uterus. Both compounds exhibit considerable antimicrobial, antispasmodic, and anti-inflammatory effects and due to these properties, they were studied in this in vitro model of premature birth induced by infection. All uterine tissues were studied in uterine contraction tests to determine the inhibitory effect of TM, CAR (10, 56, 100, 150, and 230 μM), and nifedipine (a calcium channel antagonist) on phasic and tonic contraction induced by electro- and pharmacomechanical stimuli. The quantitative determination of cyclic adenosine monophosphate (cAMP) induced by TM and CAR in the uterine lysate was carried out by ELISA. For the determination of the anti-inflammatory effect of TM, the pro-inflammatory cytokine, interleukin (IL)-1β, in uterine samples stimulated with lipopolysaccharide (LPS) was measured. Forskolin (FSK) was used as a positive control to evaluate the cAMP and cytokine levels. TM, CAR, and nifedipine inhibited the uterine contractions at the highest concentration level, however, nifedipine was the most equipotent (p<0.05). In addition, TM and CAR did not increase the intracellular cAMP production in comparison with FSK (p<0.05). However, both compounds were able to decrease the LPS-induced production in a concentration-dependent manner that was considered statistically significant (p>0.05). Finally, both the anti-inflammatory and uterine relaxing effects induced by TM and CAR were neither associated with the increase in cAMP levels nor with the production of IL-1β in pregnant rat uterine samples. Therefore, TM and CAR can be considered as alternative adjuvants for the treatment of infection-induced preterm labor. Before the in vitro experiments, an in-silico analysis was conducted using the Expaisy online server to evaluate the biological effects of thymol on uterine contraction. It is crucial to know the interaction and identification of genes encoding the Voltage-dependent L-type calcium channel subunit alpha-1C proteins, because of the functional relationship it may have in the inhibition of the uterine contraction. These properties place TM as a potentially safe and effective adjuvant agent in cases of preterm birth, an area of pharmacological treatment that requires urgent improvement.

Left Atrial Mechanics and Atrioventricular Coupling in Hypertension With Supra-Normal Left Ventricular Ejection Fraction.

Supra-normal left ventricular ejection fraction (snLVEF) represents a heterogeneous group with distinct prognoses. Left atrial (LA) strain, measured by speckle tracking echocardiography (STE), is a validated prognostic indicator. This study aimed to evaluate LA and left ventricular (LV) mechanical strains in hypertensive patients with snLVEF. This retrospective study included 101 patients (mean age 59.7 ± 8.4 years; 61.4% men) with primary arterial hypertension and preserved LVEF (≥50%). Patients were categorized into low-normal LVEF (lnLVEF; 50%-59%), mid-normal LVEF (mnLVEF; 60%-69%), and snLVEF (≥70%). LV global longitudinal strain (LVGLS) and LA strains during reservoir (LASr), conduit (LAScd), and contraction (LASct) phases were measured using STE. Relative wall thickness was significantly higher in snLVEF patients compared to mnLVEF (p < 0.01), with no difference in LVGLS (p = 0.933). Compared to mnLVEF, snLVEF patients had reduced LASr and LAScd (both p<0.01) but preserved LASct (p=0.057). In contrast, lnLVEF patients showed greater reductions in all phasic LA strains (all p<0.01). Loess regression revealed an inverted U-shaped relationship between LASr and LVEF, peaking at LVEF 65%-70%. The mitral E/e'mean ratio and LVGLS correlated moderately to strongly with LASr (r = -0.39 and r = -0.65, respectively; both p < 0.001). Hypertensive patients with snLVEF exhibit impaired LA reservoir and conduit functions while maintaining pump function, suggesting snLVEF may be an intermediate stage between mnLVEF and lnLVEF as hypertension progresses. Further studies are needed to explore the prognostic potential of LA strain in this population.

Unmasking the Epicardial Adipose Tissue-Left Atrial Strain Nexus in HFpEF: A Potential Echocardiographic Signature of Cardiac Adaptation.

This study aims to investigate the relationship between epicardial adipose tissue (EAT) and left atrial function in patients with preserved ejection fraction heart failure (HFpEF). We conducted a cross-sectional study involving 113 patients diagnosed with HFpEF and 48 control subjects without heart failure. Echocardiography was performed to assess EAT thickness and left atrial function was quantified using Autostrain left atrium (LA), including left atrial strain during reservoir phase (LASr), left atrial strain during conduit phase (LAScd), and left atrial strain during contraction phase (LASct). Clinical and biochemical parameters were correlated with EAT and LA strain using regression analyses and generating receiver operating characteristic (ROC) curves for left atrial strain parameters. EAT thickness was significantly greater in the HFpEF group (8.0±1.0mm) compared to the control group (5.0±0.7mm). HFpEF group exhibited poorer left ventricle diastolic function, indicated by lower e' velocity, E/A ratio, and higher E/e' values. Left atrial strain parameters, including LASr (22.4±9.1%), LAScd (11.9±6.9%), and LASct (10.5±3.9%), were all lower in the HFpEF. EAT thickness was positively correlated with NT-proBNP, triglycerides, and fasting blood glucose. Multivariate analysis revealed significant associations between EAT and LA strain parameters even after adjusting for potential confounders. ROC curve analysis indicated that LASr had the highest diagnostic accuracy for HFpEF. Additionally, left atrial strain parameters were strongly correlated with left ventricular diastolic function. Patients with HFpEF exhibit increased EAT thickness and reduced left atrial function. The thickening of EAT is associated with a decrease in left atrial strain. LA strain, particularly LASr, may serve as a sensitive indicator for early detection of left ventricular diastolic dysfunction in HFpEF.

Using Functional Magnetic Resonance Imaging to Detect Differences in Micturition-Related Brain Activity Between Volitional and Involuntary Detrusor Contractions.

Detrusor contractions can be classified as either volitional or involuntary. The latter are a hallmark of urge urinary incontinence. Understanding differences in neuroactivation associated with both types of contractions can help elucidate pathophysiology and therapeutic targets. In this study we aim to compare brain activity associated with voluntary and involuntary detrusor contractions. Twenty seven stroke survivors with secondary storage lower urinary tract symptoms underwent four filling cycles of simultaneous urodynamics and BOLD-signal fMRI. After each fill, participants were instructed to void. Voids inside the designated 10-s period were considered voluntary contractions. All others were considered involuntary. Each contraction was then segmented into phases: Early (10 s before start of contraction), Rise (start of contraction to peak vesical pressure), Plateau, and Fall (from peak pressure to resolution of the contraction). BOLD-effect was compared between the two contraction types, employing a minimum cluster size of 25 voxels and significance threshold at p < 0.005. Compared to volitional contractions, involuntary contractions were associated with diminished brain activity in each contraction phase. During the Early phase, this difference was most prominent in areas implicated with sensory and autonomic function, shifting to regions tasked with motor control as the contraction continued and eventually attenuating as the contraction resolved. This study uniquely contrasts brain activation associated with volitional and involuntary contractions. Relative to involuntary contractions, volitional contractions revealed increased activity in motor, sensory, and executive functioning regions. These findings reflect both the physiological mechanism of volitional contractions and suggest the displacement of this mechanism by a subcortical reflex in involuntary contractions. NCT05301335.

Aging-induced changes in lymphatic muscle cell transcriptomes are associated with reduced pumping of peripheral collecting lymphatic vessels in mice.

Lymphatic muscle cells (LMCs) within the wall of collecting lymphatic vessels exhibit tonic and autonomous phasic contractions, which drive active lymph transport to maintain tissue-fluid homeostasis and support immune surveillance. Damage to LMCs disrupts lymphatic function and is related to various diseases. Despite their importance, knowledge of the gene transcriptional signatures in LMCs and how they relate to lymphatic function in normal and disease contexts is largely missing. We have generated a comprehensive transcriptional single-cell atlas-including LMCs-of peripheral collecting lymphatic vessels from mice across the lifespan. We identified genes that distinguish LMCs from other types of muscle cells, characterized the phenotypical and transcriptomic changes in LMCs in aged vessels, and identified a proinflammatory microenvironment that suppresses the contractile apparatus in LMCs from advanced-aged mice. Our findings provide a valuable resource to accelerate future research for the identification of potential drug targets on LMCs to improve lymphatic vessel function.

Analysis of initial singularity admitting viable bounce models

Analysis of initial singularity admitting viable bounce models

Analysis of initial singularity admitting viable bounce models

Analysis of initial singularity admitting viable bounce models

Ratcheting fluid pumps: Using generalized polynomial chaos expansions to assess pumping performance and sensitivity

A large diversity of fluid pumps is found throughout nature. The study of these pumps has provided insights into fundamental fluid dynamic processes and inspiration for the development of micro-fluid devices. Recent work by Thiria and Zhang [Appl. Phys. Lett. 106, 054106 (2015)] demonstrated how a reciprocal, valveless pump with a geometric asymmetry could drive net fluid flow due to an impedance mismatch when the fluid moves in different directions. Their pump's geometry is reminiscent of the asymmetries seen in the chains of contractile chambers that form the insect heart and mammalian lymphangions. Inspired by these similarities, we further explored the role of such geometric asymmetry in driving bulk flow in a preferred direction. We used an open-source implementation of the immersed boundary method to solve the fluid-structure interaction problem of a viscous fluid moving through a sawtooth channel whose walls move up and down with a reciprocal motion. Using a machine learning approach based on generalized polynomial chaos expansions, we fully described the model's behavior over the target 3-dimensional design space, composed of input Reynolds numbers (Rein), pumping frequencies, and duty cycles. Scaling studies showed that the pump is more effective at higher intermediate Rein. Moreover, greater volumetric flow rates were observed for near extremal duty cycles, with higher duty cycles (longer contraction and shorter expansion phases) resulting in the highest bulk flow rates.

Comparison of Preoperative and Postoperative Conventional and Speckle Tracking Echocardiographic Parameters in Living Liver Donors.

Introduction We aimed toassess whether partial hepatectomy has an influence on conventional and speckle tracking parameters on echocardiography in living liver donors in the early postoperative period. Methods This study was a retrospective study to investigate the cardiac effects of liver donation after the transplant operation in a high-volume liver transplant center. Ninety living liver donors were included in the study. The echocardiographic images were obtained from 90 living liver donors before and five to seven days after the operation. The echocardiographic examinations were evaluated with a Philips Epiq 7 ultrasound system (Philips Ultrasound; Bothell, WA, USA) by experienced cardiologists in accordance with the recommendations of the American Society of Echocardiography. These included M-mode, two-dimensional imaging, tissue Doppler assessment at the septal and lateral mitral annulus, and strain imaging in all patients at rest in the left decubitus position. The changes in echocardiographic parameters in living liver donors were analyzed.Paired T-test was used to assess significant differences. Results The left ventricular (LV) global longitudinal strain (GLS), right ventricular (RV)GLS, and RV free wall LS, reservoir phase of left atrial strain (LAS-r), conduit phase of LAS (LAS-cd) did not show significant changes after the operation (for all, p>0.05). However, the absolute atrial contraction phase of LAS (LAS-ct) mean value increased significantly (14.2±8.8 vs 16.6±8.3, p=0.025) postoperatively. Among the conventional echo parameters, isovolumic relaxation time (IVRT) and the E/A ratio demonstrated notable postoperative alterations.The mean IVRT (87.3 ± 22.4 vs. 80.8 ± 18.1, p=0.014) and E/A ratio (1.5 ± 0.5 vs. 1.3 ± 0.3, p=0.012) exhibited a postoperative decline. Conclusions To the best of our knowledge, our study is the first to evaluate the effect of partial hepatectomy on cardiac functions by echocardiography in living liver donors, and there was no deterioration in the functions of both the ventricles and left atrium.

Innovative Technique for Muscle Exploration in Patients With COPD

Chronic obstructive pulmonary disease (COPD) is associated with numerous comorbidities, including muscle involvement which consists of changes in the structure and function of peripheral and respiratory muscles. Ultrasound can provide a non-invasive assessment of muscle damage. Ultrasound assessment of the quadriceps contractility index (Qci) is feasible, rapid, simple and reliable. Numerous studies have demonstrated that Qci is linked to the severity of COPD, clinical symptoms and respiratory muscle activity. Furthermore, ultrasound makes it possible to observe the dynamics of the diaphragm by measuring its amplitude, its contraction speed and the duration of each contraction phase. Ultrasound examination of muscle damage in COPD could constitute a promising new tool to assess the severity of the disease.

Thrust system, flower structures and transpressive duplexes in Zeidun-Kareim Belt, Central Tectonic Province, Egyptian Nubian Shield (East African Orogen)

In this study, we explore thrust system, flower structures and transpressive duplexes in the Zeidun-Kareim belt (ZKB) in the Egyptian Nubian Shield (ENS; northwestern ANS). Filed observations and the measured stretched lineations along thrust planes reveal two main thrusting directions; ESE- (to NE- and NNE-)- and NW- (to WNW-)-directions belonging to two main phases of contraction. The timing of both phases is indirectly constrained. The older ESE- (to NE- and NNE-)-vergent thrusting is attributed to the E-W Gondwana assembly. The younger NW- (to WNW-)-vergent thrusting is akin to the Najd Orogeny. The poles to the in-sequence thrusts lie close to the poles of stretching lineations. The mean orientations of thrust propagation are, respectively, 059° and 309°. Propagation of thrusting along the two main thrusting directions resulted in the formation of a complete geometry of thrust duplex system, imbricate nappe stacking, flower structures and thrust-related folding. The top-to- ESE- (to NE- and NNE-) transpression reflects dextral sense, whereas the top-to- NW- (to WNW-) transpression exhibits sinistral sense, in compatible with those recorded and argued by many authors elsewhere in the ENS and the entire ANS. Our study fully constraints the ZKB spathio-temporal tectonic evolution which involves three main stages.

Greater motor unit discharge rate during rapid contractions in chronically strength-trained individuals.

Though similar motor unit (MU) discharge properties have been observed during slow sustained contractions between chronically strength-trained (ST) and untrained (UT) individuals, it is currently unknown whether differences between these groups exist for when maximal in vivo MU discharge rate is assessed during rapid, maximal rate of force development (RFD) contractions. Therefore, we compared MU discharge characteristics and RFD during rapid contractions in chronic ST and UT individuals. The investigations were performed in two independent cohorts of chronically ST men, with trained elbow flexors (experiment 1, n = 13, 6 ± 4 yr of training experience) or knee extensors (experiment 2, n = 11, 9 ± 4 yr of experience), and compared with those of UT (n = 12 and n = 10, respectively). ST individuals had greater absolute elbow flexion and knee extension RFD throughout the first 150 ms of rapid contractions compared with UT, but this difference was absent for relative RFD. ST exhibited higher initial MU discharge rate in both biceps brachii (74 [68, 80] vs. 56 [50, 63] pulses per second (pps), P < 0.0001) and vastus lateralis (102 [90, 115] vs. 76 [63, 90] pps, P = 0.0025) and a greater average number of MU discharges per second in both trained muscles in the early phase of rapid contractions. We provide novel evidence for a higher maximal MU discharge rate in strength-trained individuals. Interestingly, despite the augmented output of the spinal cord, no differences in relative RFD were observed, which suggests either greater maximal force enhancement of ST compared with UT and/or slowing of the intrinsic contractile properties by prolonged strength training.NEW & NOTEWORTHY Chronically strength-trained and untrained individuals show similar motor unit discharge rates during slow sustained contractions, however, potential differences in motor unit discharge rates during rapid contractions remained unclear. Here, we show greater maximal motor unit discharge rates during rapid contractions of chronically strength-trained individuals. However, the augmented spinal cord output of strength-trained individuals did not lead to greater relative maximal rate of force development compared with untrained men.

Prediction of the Technology Stock Market in American: based on Apple, Microsoft and Netflix

Abstract. Stock market has been and will always be the central of the financial market. It is also a leading indicator of the economy react before the business cycle. Thus, predicted the trend of the stock market should be considered by market participants, policymakers and academicians. Simultaneously, technology stock market is gradually dominating the market. Under such a background, this paper will forecast the trend of the technology stock market based on a few technology companies, which are highly weighted in the technology industry, via the Autoregressive Integrated Moving Average (ARIMA) model. This study has successfully predicted the price of the technology stock market, which the predicted outcome is a close match to the actual price. The trend of the technology market analyzed by the ARIMA model with first order difference parameters, is going upward. The result represents American business cycle is undergoing a transition from contraction phase to recovery phase to some extent.

Normal ranges of left atrial phasic strains and strain rates by 2D speckle-tracking echocardiography in pediatrics: a systematic review and meta-analysis

Establishing normal values of left atrial (LA) phasic strains and strain rates is essential for distinguishing between normal and abnormal functions, determining the degree of abnormality, and understanding the clinical significance of reported values in pediatrics. This meta-analysis aimed to establish normal values of two-dimensional speckle-tracking echocardiography (2DSTE)-derived LA phasic strains and strain rates in the pediatric population and identify the sources of inter-study heterogeneity for these values. A comprehensive search of PubMed, Scopus, and Embase databases was conducted using keywords such as “left atrial/left atrium,” “strain/speckle/deformation,” and “echocardiography” combined with pediatric age categories. Inclusion criteria comprised English-language human studies involving healthy subjects under 18 years of age. Subjects were categorized as neonates (up to 1 month), infants (1–12 months), and children (1–18 years). A random-effects model was applied to determine 2DSTE-derived LA strains and strain rates, and a meta-regression analysis was performed to investigate inter-study heterogeneity. Our analysis included 17 studies involving 1448 healthy subjects. For children, the mean values of LA strains during the reservoir, conduit, and contraction phases were 47.3% (95% CI 42.5–52.1%), 32.8% (95% CI 27.8–37.8%), and 12% (95% CI 10.0–14.1%), respectively. The mean values for LA strain rates were 2.4 s−1 (95% CI 1.1–3.8 s−1), 4.3 s−1 (95% CI 0.6–8.0 s−1), and 2.4 s−1 (95% CI 0.4–4.5 s−1), respectively. Inter-study heterogeneity for 2DSTE-derived LA phasic strains and strain rates was attributed to factors such as the number of study participants, publication year, software utilized, gating methods, the number of analyzed segments, the geographical region of the study, and heart rate. This study established the normal range of 2DSTE-derived LA phasic strains and strain rates. Additionally, inter-study heterogeneity was found to be influenced by various demographic, physiologic, and methodological factors.