Mild Contraction Research Articles

Neuromuscular disease auxiliary diagnosis using a portable magnetomyographic system.

The measurement of electromyography (EMG) signals with needle electrodes is widely used in clinical settings for diagnosing neuromuscular diseases. Patients experience pain during needle EMG testing. It is significant to develop alternative diagnostic modalities. This paper proposes a portable magnetomyography (MMG) measurement system for neuromuscular disease auxiliary diagnosis. Firstly, the design and operating principle of the system are introduced. The feasibility of using the system for auxiliary diagnosis of neuromuscular diseases is then studied. The magnetic signals and needle EMG signals of thirty subjects were collected and compared. It is found that the amplitude of muscle magnetic field signal increases during mild muscle contraction, and the signal magnitudes of the patients are smaller than those of normal subjects. The diseased muscles tested in the experiment can be distinguished from the normal muscles based on the signal amplitude, using a threshold value of 6 pT. The MMG diagnosis results align well with the needle EMG diagnosis. In addition, the MMG measurement indicates that there is a persistence of spontaneous activity in the diseased muscle. The experimental results demonstrate that it is feasible to auxiliary diagnose neuromuscular diseases using the portable MMG system, which offers the advantages of non-contact and painless measurements. After more in-depth, systematic, and quantitative research, the portable MMG could potentially be used for auxiliary diagnosis of neuromuscular diseases.

The Occurrence of Small, Short-period Planets Younger than 200 Myr with TESS

Within the first few hundreds of millions of years, many physical processes sculpt the eventual properties of young planets. NASA’s Transiting Exoplanet Survey Satellite (TESS) mission has surveyed young stellar associations across the entire sky for transiting planets, providing glimpses into the various stages of planetary evolution. Using our own detection pipeline, we search a magnitude-limited sample of 7219 young stars (≲200 Myr) observed in the first 4 yr of TESS for small (2–8 R ⊕), short period (1.6–20 days) transiting planets. The completeness of our survey is characterized by a series of injection and recovery simulations. Our analysis of TESS 2 minute cadence and Full Frame Image (FFI) light curves recover all known TESS Objects of Interest (TOIs), as well as four new planet candidates not previously identified as TOIs. We derive an occurrence rate of 35−10+13% for mini-Neptunes and 27−8+10% for super-Neptunes from the 2 minute cadence data, and 22−6.8+8.6 % for mini-Neptunes and 13−4.9+3.9 % for super-Neptunes from the FFI data. To independently validate our results, we compare our survey yield with the predicted planet yield assuming Kepler planet statistics. We consistently find a mild increase in the occurrence of super-Neptunes and a significant increase in the occurrence of Neptune-sized planets with orbital periods of 6.2–12 days when compared to their mature counterparts. The young planet distribution from our study is most consistent with evolution models describing the early contraction of hydrogen-dominated atmospheres undergoing atmospheric escape and inconsistent with heavier atmosphere models offering only mild radial contraction early on.

The Power of Substitution: The Great German Gas Debate in Retrospect

ABSTRACT: The Russian attack on Ukraine in February 2022 laid bare Germany's dependence on Russian energy imports and ignited a heated debate on the costs of a cutoff from Russian gas. While one side predicted economic collapse, the other side (ours) predicted "substantial but manageable" economic costs due to households and firms adapting to the shock. Using the empirical evidence now at hand, this paper studies the adjustment of the German economy after Russia weaponized gas exports by cutting Germany off from gas supplies in the summer of 2022. We document two key margins of adjustment. First, Germany was able to replace substantial amounts of Russian gas with imports from third countries, underscoring the insurance provided by openness to international trade. Second, the German economy reduced gas consumption by about 20 percent, driven mostly by industry (26 percent) and households (17 percent). The economic costs of demand reduction were manageable with the economy as a whole only experiencing a mild one-quarter contraction in the winter of 2022–2023 and then stagnating. Overall industrial production decoupled from production in energy-intensive sectors (which did see large drops) and declined only slightly. We draw a number of key lessons from this important case study about the insurance offered by access to global markets and the power of substitution, specifically that supply shocks have dramatically smaller costs when elasticities of substitution are very low (but nonzero) compared to a truly zero elasticity.

Serial blood volume measurements in patients with compensated chronic heart failure: How do volume profiles change over time?

Among patients with chronic heart failure (HF) intravascular volume profiles vary significantly despite similar clinical compensation. However, little is known regarding changes in blood volume (BV) profiles over time. The objective of this analysis was to identify the extent and character of changes in volume profiles over time. A prospective analysis was undertaken in patients who were hospitalized and treated for fluid overload. Quantitative BV analyses were obtained in a compensated state at hospital discharge (baseline) and follow-up at 1, 3, and 6 mo. Data were available on 10 patients who remained stable without rehospitalization or medication change over a 6-mo period. Baseline BV profiles were highly variable at hospital discharge with an average deviation of +28% above normal in 6 patients and normal BV in 4 patients. Over the follow-up period, the median change in BV was -201 mL [-3% (-6, +3%)] from baseline with profiles remaining in the same volume category in 9 out of 10 patients. Crossover from normal BV to mild contraction (-13% of normal) occurred in one patient. Red blood cell mass demonstrated the largest change over 6 mo [median -275 (-410, +175) mL] with a deviation from normal of -14 (-20, +8) % (reflecting mild anemia). These findings suggest that BV profiles in clinically compensated patients with HF do not change substantially over a 6-mo period regardless of baseline expanded or normal BV. This lack of change in volume profiles particularly from an expanded BV has implications for long-term volume management, clinical outcomes, and also our understanding of volume homeostasis in HF.NEW & NOTEWORTHY The novel findings of this study demonstrate that blood volume profiles while highly variable in clinically compensated patients with HF on stable medical therapy do not change substantially over a 6-mo period regardless of baseline expanded or normal blood volumes. This lack of change in volume profiles particularly from an expanded blood volume has implications for long-term volume management and also for how we understand the pathophysiology of volume homeostasis in chronic HF.

Sex-specific reference values for total, central, and peripheral latency of motor evoked potentials from a large cohort.

Differentiating between physiologic and altered motor evoked potentials (MEPs) to transcranial magnetic stimulation (TMS) is crucial in clinical practice. Some physical characteristics, such as height and age, introduce sources of variability unrelated to neural dysfunction. We provided new age- and height-adjusted normal values for cortical latency, central motor conduction time (CMCT), and peripheral motor conduction time (PMCT) from a large cohort of healthy subjects. Previously reported data from 587 participants were re-analyzed. Nervous system disorders were ruled out by clinical examination and magnetic resonance imaging. MEP latency was determined as stimulus-to-response latency through stimulation with a circular coil over the "hot spot" of the First Dorsal Interosseous and Tibialis Anterior muscles, during mild tonic contraction. CMCT was estimated as the difference between MEP cortical latency and PMCT by radicular magnetic stimulation. Additionally, right-to-left differences were calculated. For each parameter, multiple linear regression models of increasing complexity were fitted using height, age, and sex as regressors. Motor evoked potential cortical latency, PMCT, and CMCT were shown to be age- and height-dependent, although age had only a small effect on CMCT. Relying on Bayesian information criterion for model selection, MEP cortical latency and PMCT were explained best by linear models indicating a positive correlation with both height and age. Also, CMCT to lower limbs positively correlated with height and age. CMCT to upper limbs positively correlated to height, but slightly inversely correlated to age, as supported by non-parametric bootstrap analysis. Males had longer cortical latencies and CMCT to lower limbs, as well as longer PMCT and cortical latencies to upper limbs, even when accounting for differences in body height. Right-to-left-differences were independent of height, age, and sex. Based on the selected regression models, sex-specific reference values were obtained for all TMS-related latencies and inter-side differences, with adjustments for height and age, where warranted. A significant relationship was observed between height and age and all MEP latency values, in both upper and lower limbs. These set of reference values facilitate the evaluation of MEPs in clinical studies and research settings. Unlike previous reports, we also highlighted the contribution of sex.

Anophthalmic socket syndrome: Management and cosmetic outcome

To describe the management strategy and evaluate the outcome of Anophthalmic socket syndrome. This retrospective case study includes 40 patients with anophthalmic socket syndrome who attended the orbit and ocular oncology department of Ispahani Islamia Eye Hospital from January 1, 2018, to June 31, 2021 were included in this study. All the information regarding age, gender, initial pathology, type of initial surgery, implant, degree of contraction, the procedure of socket reconstruction, the management outcome and complication were recorded and analyzed correctly. 17 males (42.5%) and 23 females (57.5%) with a mean age of 24.47 years were included in the study. Trauma (30%) and Tumour (25%) were the main reasons for initial eye removal. Enucleation performed in 24 (60%) cases was the most common initial surgery. The primary implant was not done in 20 (50%) cases. Mild socket contraction (grade 1) was recorded in 10 (25%) cases. Moderate contraction (grade 2 and 3) in 25(62.5%) cases and severe contraction (grade 4) in 5(12.5%) cases were recorded. Only fornix forming suture was done in 10 (25%) cases, mucous membrane graft (MMG) was done in 27 (67.5%) cases and dermis fat graft was done in 3 (7.5%) cases. All the patients were followed up routinely for six months. The outcome was good in 16 (40%) cases, acceptable in 20 (50%), and poor in 4 (10%) cases. A common complication was infection (5%) and fat atrophy (5%).: Anophthalmic socket syndrome remains a challenging entity for the oculoplastic surgeon. Multiple factors help to determine the overall prognosis of socket reconstruction. The goal of management is to provide a socket that can maintain a cosmetically acceptable prosthesis. Timely detection, proper correction of the underlying pathology and a high level of care directly correlate with expected surgical outcomes.

Effects of muscle energy technique on improving the range of motion and pain in patients with frozen shoulder

Introduction and Aim: Muscle Energy Technique (MET) is a type of manual treatment that utilises the energy of the muscle in the form of a mild isometric contraction to stretch the muscle and relax the muscles through reciprocal or autogenic inhibition. An idiopathic ailment of the shoulder joint known as frozen shoulder is characterised by a rapid onset of shoulder discomfort and a limitation in mobility. Much research has been conducted to determine how various manual approaches affect shoulder discomfort. This study focuses on how MET affects pain and range of motion during the initial stages of rehabilitation.
 Materials and Methods: Patients who are diagnosed with frozen shoulders with fulfilling the inclusion and exclusion criteria were selected for the study. In the current study, thirty patients who had a prevalence of musculoskeletal complications of the frozen shoulder were selected. Out of which eighteen are male and twelve are female. To identify the prevalence each patient's range of motion and VAS Score for pain sensation were recorded. The same patients have been introduced to MET for another seven days. MET includes 5 repetitions/sets, 3 sets/session, and 1 session/day. A statistical test was performed to identify the significant difference between pre and post-values.
 Results: Most of the patients had an average range of motion (Flexion) (of 132±18.96), range of motion (Abduction) of (107.00±12.77), range of motion (Rotation) of (63.50±9.39) and VAS score was (5.96±1.29). Most patients showed the improvement in range of motion and a decrease in pain sensation as per the VAS Score.
 Conclusion: This study shows that MET effectively improves the range of motion and functional ability, relieving pain in Frozen Shoulder patients in the early stage of rehabilitation.

Image-guided stent-directed irreversible electroporation for circumferential ablation in the rat esophagus.

Background: Irreversible electroporation (IRE) has been investigated in the alimentary tract; however, the lack of dedicated electrodes and insufficient tissue responses made its application limited. The aim of this study was to investigate the efficacy and safety of image-guided stent-directed IRE in the rat esophagus. Methods: The bipolar self-expandable electrode (SE) was developed using the braiding technique. A finite element analysis was performed to validate optimal electrical field strength for the rat esophagus. A total of 40 out of 50 rats received stent-directed IRE and were sacrificed at 10h, 3days, 7days, and 28days of 10 each. The remaining ten rats underwent a sham procedure. The outcomes of stent-directed IRE were assessed by esophagography and histological responses. Results: Stent-directed IRE was technically successful in all rats with mild muscle contraction. The heart rate dropped immediately and gradually recovered at 180s. TUNEL and caspase-3 with submucosal thickness significantly increased at 10h and Day 3 compared with those of the sham control (all p < 0.001). The thickness of epithelial layers with collagen deposition significantly decreased at 10h and Day 3 (all p < 0.001), however, increased at Day 7 compared with that of the sham control (all p < 0.05). The Ki67-positive deposition significantly increased at Day 3 and 7 compared with that of the sham control (all p < 0.001). All variables were similar to those of the sham control at Day 28. Conclusion: Image-guided stent-directed IRE was effective and safe in the rat esophagus. It seems to have effectively and evenly induced cell death and gradually recovered with cellular regeneration.

Simultaneous measurement of the size and methylation of chromosome 4qA-D4Z4 repeats in facioscapulohumeral muscular dystrophy by long-read sequencing

BackgroundFacioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant muscular disorder characterized by asymmetric muscle wasting and weakness. FSHD can be subdivided into two types: FSHD1, caused by contraction of the D4Z4 repeat on chromosome 4q35, and FSHD2, caused by mild contraction of the D4Z4 repeat plus aberrant hypomethylation mediated by genetic variants in SMCHD1, DNMT3B, or LRIF1. Genetic diagnosis of FSHD is challenging because of the complex procedures required.MethodsWe applied Nanopore CRISPR/Cas9-targeted resequencing for the diagnosis of FSHD by simultaneous detection of D4Z4 repeat length and methylation status at nucleotide level in genetically-confirmed and suspected patients.ResultsWe found significant hypomethylation of contracted 4q-D4Z4 repeats in FSHD1, and both 4q- and 10q-D4Z4 repeats in FSHD2. We also found that the hypomethylation in the contracted D4Z4 in FSHD1 is moderately correlated with patient phenotypes.ConclusionsOur method contributes to the development for the diagnosis of FSHD using Nanopore long-read sequencing. This finding might give insight into the mechanisms by which repeat contraction causes disease pathogenesis.

Cutaneous silent period modulation by tooth clenching, tonic and phasic limb movements in healthy subjects.

We aimed to examine the modulation of the cutaneous silent period (CSP) by tooth clenching and contralateral tonic dorsiflexion of lower limb and phasic voluntary movements of upper limb. In 18 healthy subjects, we recorded CSP on right thenar muscle after painful stimulation of index finger during mild contraction at six conditions: baseline, maximum tooth clenching, contralateral tonic dorsiflexion of foot, as well as at the beginning (RT1), in the middle (RT2) and at last part (RT3) of the contralateral phasic wrist extension. We measured latency and duration and calculated suppression indices. During tooth clenching, the suppression index of second inhibitory phase (I2) was significantly higher than that at baseline condition. The suppression index of first inhibitory phase (I1) was reduced in tonic dorsiflexion. The I2 durations in RT2 and RT3 were longer than that at baseline. The I2 suppression indices during RT1, RT2, and RT3 were significantly higher than that at baseline condition (p < 0.05). The tooth clenching has an inhibitory effect on CSP. The contralateral phasic hand movements caused higher suppression index. The CSP is modulated by remote influences differently depending on the type of muscle contraction (tonic vs. phasic) and/or where it is realized (tooth, upper or lower limb).

Preclinical Studies to Evaluate the Gut Stimulatory Activity of Aloe Musabbar.

Background Constipation is a common functional gastrointestinal disorder. Medicines derived from nature are routinely used to treat it. The present study evaluates the gut stimulatory activity of Aloe musabbar (processed powder of Aloe vera) using in vitro and in vivo models for gut stimulatory activity. Materials and Methods In vitro tests were conducted on isolated rat colon, guinea pig ileum, and rabbit jejunum, while in vivo study was performed using mice intestinal transit time. Aloe musabbar (A. musabbar) was tested at doses 0.2–200 mg/mL (in-vitro study) and 86.6 mg/kg (in vivo study). In vitro studies were done in the presence and absence of atropine sulphate (1 ng/ml). The results were statistically analyzed, and p < 0.05 was considered to indicate the significance. Results A. musabbar exhibited dose-dependent increase in the smooth muscle contraction of isolated gut tissues. Presence of atropine minimized the contractile responses and shifted the dose-response curves towards the right-hand side. The intestinal transit time in mice was observed to be increased significantly (p < 0.01) in A. musabbar-treated animals, when compared with normal animals. Conclusion A mild smooth muscle contraction induced by A. musabbar suggests that it can stimulate intestinal bowel movement without causing spasms. The diminished responses in the presence of atropine indicated that the gut stimulatory activity could be mediated partially through parasympathetic innervations. More studies are needed to determine the precise mechanism of action including the specific active ingredient responsible for the gut stimulatory activity.

A Mild Dyssynchronous Contraction Pattern Detected by SPECT Myocardial Perfusion Imaging Predicts Super-Response to Cardiac Resynchronization Therapy.

BackgroundUsing single photon emission computed tomography myocardial perfusion imaging (SPECT MPI) with phase analysis (PA), we aimed to identify the predictive value of a new contraction pattern in cardiac resynchronization therapy (CRT) response.MethodsLeft ventricular mechanical dyssynchrony (LVMD) was evaluated using SPECT MPI with PA in non-ischemic dilated cardiomyopathy (DCM) patients with left bundle branch block (LBBB) indicated for CRT. CRT super-response was defined as LV ejection fraction (EF) ≥50% or an absolute increase of LVEF >15%. The LV contraction was categorized as the mild dyssynchronous pattern when the phase standard deviation (PSD) ≤ 40.3° and phase histogram bandwidth (PBW) ≤ 111.9°, otherwise it was defined as severe dyssynchronous pattern which was further characterized as U-shaped, heterogeneous or homogenous pattern.ResultsThe final cohort comprised 74 patients, including 32 (43.2%) in mild dyssynchronous group, 17 (23%) in U-shaped group, 19 (25.7%) in heterogeneous group, and 6 (8.1%) in homogenous group. The mild dyssynchronous group had lower PSD and PBW than U-shaped, heterogeneous, and homogenous groups (P < 0.0001). Compared to patients with the heterogeneous pattern, the odds ratios (ORs) with 95% confidence intervals (CIs) for CRT super-response were 10.182(2.43–42.663), 12.8(2.545–64.372), and 2.667(0.327–21.773) for patients with mild dyssynchronous, U-shaped, and homogenous pattern, respectively. After multivariable adjustment, mild dyssynchronous group remained associated with increased CRT super-response (adjusted OR 5.709, 95% CI 1.152–28.293). Kaplan-Meier curves showed that mild dyssynchronous group demonstrated a better long-term prognosis.ConclusionsThe mild dyssynchronous pattern in patients with DCM is associated with an increased CRT super-response and better long-term prognosis.

The effect of intra-vaginal oxytocin on sexual function in breastfeeding mothers: a randomized triple-blind placebo-controlled trial

BackgroundConsidering the importance of sexual function, high prevalence of sexual dysfunction (especially dyspareunia caused by atrophic vaginitis) in breastfeeding women, and lack of effective interventions, the present research aimed to determine the effect of oxytocin (OXT) vaginal gel on sexual function (primary outcome), sexual satisfaction, and depression (secondary outcomes) in the breastfeeding women.MethodsThis randomized triple-blind controlled trial was conducted on 64 breastfeeding women who referred to health centers in the city of Tabriz, Iran, in 2020-21. Participants were equally assigned to intervention/control groups using block randomization. 200 IU of OXT vaginal gel was given to the participants in the intervention group daily for eight week and the same protocol was carried out for the control group with placebo. Standard questionnaires of Female Sexual Function Index (FSFI), Edinburgh Postpartum Depression Scale (EPDS) and Sexual satisfaction scale for women (SSSW) were completed at baseline and 8 weeks after intervention. ANCOVA test was used to compare post-intervention mean score of the groups, adjusted for the baseline values.ResultsAfter intervention, there was no statistically significant difference between groups in terms of mean total score of FSFI (Adjusted Mean Difference (AMD): 1.14; 95% Confidence Interval (95% CI): -1.28 to 9.16; P= 0.349) and sexual satisfaction (AMD: 5.01; 95% CI: -0.53 to 10.56; P= 0.075). However, there was statistically significant difference between the groups in terms of mean scores of sexual contentment (AMD: 1.56; 95% CI: 0.29 to 2.83; P = 0.017) and depression (AMD: -1.90; 95% CI: -1.27 to -2.54; P < 0.001). One participant in the OXT group and one participant in the placebo group reported mild uterine contraction and one person in the placebo group reported vaginal burning sensations.ConclusionsNo evidence was found for the effects of OXT gel in the improvement of FSFI, even though, OXT significantly improved sexual satisfaction in the domain of contentment, and improved the symptoms of depression in comparison to the placebo group. However, a definite conclusion requires more research in this regard.Trial registrationthe Iranian Registry of Clinical Trials (IRCT), code: IRCT20120718010324N55, Date of registration: 27/05/2020, URL: https://en.irct.ir/user/trial/44986/view.

Novel insights into the pathogenesis of tendon injury: mechanotransduction and neuroplasticity.

Novel insights into the pathogenesis of tendon injury: mechanotransduction and neuroplasticity.

Dry annealing of radiation-damaged zircon: Single-crystal X-ray and Raman spectroscopy study

Structural reconstitution upon dry thermal annealing of mildly to strongly radiation-damaged, gem-quality zircon from Sri Lanka has been studied by single-crystal X-ray diffraction and Raman spectroscopy. Results of structure refinement of a strongly radiation-damaged zircon (sample GZ5, calculated alpha dose ~4 × 1018 g−1) indicate the existence of an interstitial oxygen site that is sparsely occupied (about 4% of all O atoms). Annealing of this sample at Ta (annealing temperature) = 700 °C has resulted in nearly complete recrystallization of its amorphous volume fraction and significant decrease in the occupation of O-interstitial sites. For all samples studied, annealing up to Ta ≤ 650–700 °C is characterised by preferred recovery of Raman shifts (compared to Raman FWHMs; full width at half band maximum) and extensive contraction of the unit-cell volume, in particular along unit-cell dimension a. This low-T annealing is dominated by epitaxial growth of the crystalline volume fraction at the expense of the amorphous volume fraction, and general recovery of low-energy defects. During annealing at Ta = 700–1400 °C there is preferred recovery of Raman FWHMs (compared to Raman shifts) and only mild unit-cell contraction. High-T annealing is dominated by the recovery of high-energy defects such as recombination of cation Frenkel pairs. Here, unit-cell parameter a shows a remarkable behaviour (namely, mild re-increase at Ta = 700–1150 °C and mild final shrinking at Ta = 1000–1400 °C), which is attributed to enhanced contortion of ZrO8 polyhedrons due to cation repulsion. The combined data set of Raman band and unit-cell parameter presented herein will help analysts to assign Raman spectra of annealed unknowns to certain recovery stages.

ENHANCED ACTIVE CONTRACTION OF THE TRANSVERSUS ABDOMINIS DURING WALKING

ABSTRACT Introduction: We applied three-dimensional gait analysis to assess the effects of enhanced active contraction of the transversus abdominis (EACTA) during walking. We sought to evaluate the effect of EACTA during walking in order to improve walking quality. Methods: Thirty college students were recruited and trained to perform EACTA during walking. We examined gait parameters under different conditions, including EACTA and habitual ACTA (natural walking with mild contraction of the feedforward mechanism of ACTA, HACTA) during walking using three-dimensional gait analysis. We compared differences in gait parameters under the two walking conditions using SPSS 16.0 statistical software. Results: The following gait parameters were significantly lower under EACTA conditions than under HACTA conditions (P &lt; 0.05): stance phase, 59.151% ± 1.903% vs. 59.825% ± 1.495%; stride time, 1.104 s ± 0.080 s vs. 1.134 s ± 0.073 s:; stance time, 0.656 s ± 0.057 s vs. 0.678 s ± 0.053 s; and swing time, 0.447 s ± 0.028 s vs. 0.454 s ± 0.031 s, respectively. Gait parameters single support phase and mean velocity were significantly higher for EACTA than for HACTA conditions (both P &lt; 0.05). Conclusions: Overall, the results revealed that EACTA during walking can improve gait. This method is simple, and EACTA training during walking to improve gait quality in daily life could provide a positive basis for people to strengthen the transverse abdominal muscle. Level of evidence III; Retrospective comparative study .

The impact of a national carbon price on China

As the world No.1 emitter of carbon dioxide (CO2), China has made up its mind to act on climate change. After trials in six pilot regions- Shenzhen, Shanghai, Beijing, Guangdong, Tianjin, Hubei, and Chongqing- a nationwide ETS has been established and implemented in line with the Thirteenth Five-Year Plan period (2016–2020). This paper simulates the effect of a national ETS in China using GTAP 9.1 database and a revised GTAP-E model. The simulation results show that the ETS is very effective in emissions reduction but will cause a mild economic contraction. At the sectoral level, the energy and resource sectors and energy intensive sectors are to be hit hard while most other sectors are affected negatively but insignificantly.

An Analysis of the Seasonal Cycle and the Business Cycle

Robert Barsky and Jeffrey Miron (1989) revealed the seasonal cycle of the U.S. economy from 1948 to 1985 was characterized by a “bubble-like” expansion in the second and fourth quarters, a “crash-like” contraction in the first quarter, and a mild contraction in the third quarter. We replicate, in part, their seasonal cycle analysis from 1946 to 2001. Our results are largely in line with theirs. Nonetheless, we find the seasonal cycle is not stable and can evolve across time. In particular, the Great Moderation affected both the business cycle and the seasonal cycle. Robert Barsky and Jeffrey Miron also found real aggregates, like the output, move together in the seasonal cycle across broadly defined sectors, similar to a phenomenon observed under the conventional business cycle. They posed a challenge question concerning why “the seasonal and the conventional business cycles are so similar.” To answer their question, we focus on a number of aggregate variables with a recursive application of the HP filter and find that aggregates, such as the GDP, consumption, the S&P 500 Index, and so forth, have a “bubble-like” expansion and a “crash-like” contraction in their cyclical trends in business cycle frequencies. Although preference shifts and production synergy are the two major forces that drive the seasonal cycle, we find the time-varying stochastic discount factor is the main cause of the business cycle and plays a more important role in macroeconomic fluctuations in business cycle frequencies than other factors.

Age, Height, and Sex on Motor Evoked Potentials: Translational Data From a Large Italian Cohort in a Clinical Environment.

IntroductionMotor evoked potentials (MEPs) to transcranial magnetic stimulation (TMS) are known to be susceptible to several sources of variability. However, conflicting evidences on individual characteristics in relatively small sample sizes have been reported. We investigated the effect of age, height, and sex on MEPs of the motor cortex and spinal roots in a large cohort.MethodsA total of 587 subjects clinically and neuroradiologically intact were included. MEPs were recorded during mild tonic contraction through a circular coil applied over the “hot spot” of the first dorsal interosseous and tibialis anterior muscles (TAs), bilaterally. Central motor conduction time (CMCT) was estimated as the difference between MEP cortical latency and the peripheral motor conduction time (PMCT) by cervical or lumbar magnetic stimulation. Peak-to-peak MEP amplitude to cortical stimulation and right-to-left difference of each parameter were also measured.ResultsAfter Bonferroni correction, general linear (multiple) regression analysis showed that both MEP cortical latency and PMCT at four limbs positively correlated with age and height. At lower limbs, an independent effect of sex on the same measures was also observed (with females showing smaller values than males). CMCT correlated with both age (negatively) and height (positively) when analyzed by a single regression; however, with a multiple regression analysis this significance disappeared, due to the correction for the multicollinearity within the dataset.ConclusionPhysical individual features need to be considered for a more accurate and meaningful MEPs interpretation. Both in clinical practice and in research setting, patients and controls should be matched for age, height, and sex.

Harvesting Split-thickness Skin from the Scalp Using a Scalpel.

Split-thickness skin grafts (STSGs) from the scalp may be an attractive option for patients who do not want scars on their limbs or trunk. However, not all institutions have the equipment typically used to perform STSGs. Between January 2015 and June 2017, STSGs were harvested with a No. 15 blade under local anesthesia from the scalps of 4 patients and grafted on small skin defects from facial trauma, a tattoo, and scarring, and on a large defect from burns. Epithelialization of the donor sites and graft take, secondary contraction, and color and texture match of the recipient sites were observed. Thickness of the harvested skin was confirmed by histopathologic examination. Mean patient age was 39.8 years; 2 patients were male. Epithelialization of the donor sites took a mean of 8.75 days. No hypertrophic scarring or alopecia was observed. Good graft take and relatively good color and texture match of the recipient site were achieved. Mild secondary contraction was noted in 2 cases. Histopathologic examination showed no damage to the hair follicles. The thickness of the harvested skin varied from 0.3 to 0.7 mm. Using the scalpel technique, surgeons can perform STSGs with only several blades, minimizing surgical costs. The hair follicles remain intact because the thickness of the graft skin is <1 mm. Epithelialization of the donor site is quick, and there is no visible wound on the limb or trunk. It is especially useful to cover small defects.