The onset of heterogeneity in the pinch-off of suspension drops.

SignificanceThe pinch-off of a liquid drop extruded from a nozzle is a canonical situation that involves a series of self-similar regimes ending in a finite-time singularity. This configuration allows for exploring capillary flows over a large range of scales. In the case of suspension drops, the presence of particles breaks the self-similarity by introducing a length scale that can be much larger than the particle diameter. This length scale is a signature of the heterogeneities and delimitates a regime, in which a continuum approach of a suspension can be used from a regime where the discrete nature of the particles is involved.

Associations between pinch strength, cardiovascular events and all-cause mortality in patients undergoing maintenance hemodialysis.

BACKGROUND AND AIMS: Patients undergoing maintenance hemodialysis (MHD) experience increased mortality and cardiovascular disease (CVD) risks; however, the potential connection between pinch strength (PS) and the prognosis of these patients remains unknown. Consequently, this study aimed to comprehensively assess the influence of PS and handgrip strength (HGS) on both survival and cardiovascular events (CVE) in patients undergoing MHD. METHODS: Data were gathered from patients undergoing MHD at the Hemodialysis Center of Guangzhou Red Cross Hospital in March 2021. We performed a retrospective follow-up spanning 24 months, with death serving as the primary endpoint for observation and CVE as the secondary endpoint. Multifactorial Cox regression analysis, Kaplan-Meier survival curves, trend tests, and restricted cubic spline were applied to explore the association. RESULTS: During a 24-month follow-up, data were collected from 140 patients undergoing MHD with an average age of 66.71 ± 12.61 years. Among them, 52 (37.14%) experienced mortality, whereas 36 (40.00%) had CVE without baseline CVD. Kaplan-Meier survival curves demonstrated better survival rates and reduced CVE risk for patients in the second, third, and fourth quartiles compared with those in the first quartile for PS. Adjusted analyses in different models revealed higher PS levels were independently associated with all-cause mortality (major model, model 4, HR, 0.78; 95% CI, 0.64-0.95) but not with CVE risk (unadjusted HR, 0.90; 95% CI, 0.77-1.05). Compared with lower quartile PS levels, higher PS levels significantly reduced all-cause mortality (HR, 0.31; 95% CI, 0.10-1.02), and this trend remained consistent (P for trend = 0.021). Finally, the restricted cubic spline method using different models showed a linear relationship between PS and all-cause mortality (P > 0.05), when PS exceeded 4.99 kg, the all-cause mortality of MHD patients significantly decreased. CONCLUSIONS: PS was independently associated with all-cause mortality but not with CVE in patients undergoing MHD.

Text neck is not associated with neck and upper limb disability in young adults who use smartphones.

PURPOSE: The objective of the present study was to correlate neck and upper-limb disabilities with neck flexion in university students who are smartphone users. While handling smartphones, a posture with sustained neck flexion known as "Text Neck" is usually adopted, and some authors related to musculoskeletal symptoms on the neck and the upper limb. However, recent studies state that such an association is questionable. METHODS: This is an observational study when evaluating 192 university students through questionnaires such as the Neck Disability Index (NDI), Disabilities of Arm, Shoulder, and Hand (DASH), besides the maximal neck flexion, grip and lateral pinch strength of the participants. RESULTS: The sociodemographic questionnaire demonstrated that most participants had used the device for 5 to 10 years, for five or more hours per day. The DASH questionnaire scores presented an average of 7.2 points, while the data regarding grip and lateral pinch strength showed averages of 29.5 kgf and 8.8 kgf, respectively. The NDI questionnaire scores presented an average of 10.5. The average range of motion of the maximum neck flexion was 27°. CONCLUSION: There was no association between neck flexion with the DASH and NDI or the grip and lateral pinch strength after the correlation and binary logistic regression analyses. The results show that the scores of DASH, NDI, hand grip and lateral pinch strength, have no association with the maximum neck flexion.

Using a Sensor-Embedded Baseball to Identify Finger Characteristics Related to Spin Rate and Pitching Velocity in Pitchers.

BACKGROUND: Previous investigations have shown a positive relationship between baseball pitching velocity and the kinetic chain involved in pitching motion. However, no study has examined the influence of finger characteristics on pitching velocity and rate of spin via a sensor-embedded baseball. METHODS: Twenty-one pitchers volunteered and were recruited for this study. An experimental baseball embedded with a force sensor and an inertial measurement unit was designed for pitching performance measurement. Finger length and strength were measured as dependent variables. Spin rate and velocity were independent variables. Pearson product-moment correlations (r) and intraclass correlation coefficients (ICCs) determined the relationship between finger characteristics and pitching performance. RESULTS: Finger length discrepancy, two-point pinch strength, index finger RFD (rate of force development), middle finger impulse, and force discrepancy had significant correlations with spin rate (r = 0.500~0.576, p ≤ 0.05). Finger length discrepancy, two-point pinch, three-point pinch strength, index and middle finger RFD, middle finger impulse, and force combination had significant correlations with fastball pitching velocity (r = 0.491~0.584, p ≤ 0.05). CONCLUSIONS: Finger length discrepancy, finger pinch strength, and pitching finger force including maximal force and RFD may be factors that impact fastball spin rate and fastball pitching velocity.

Movement analysis of the distal transverse arch of the dominant hand while grasping and pinching objects: A descriptive, correlational research study.

BACKGROUND: The distal transverse arches obtained from active and passive motions of the hand and the used range of motion (u-ROM) of the hand arch in activities of daily living have rarely been reported. PURPOSE: This study aimed to investigate the distal transverse arch angle of the dominant hand, the influence of age, and the u-ROM of the arch when grasping and pinching objects. STUDY DESIGN: Descriptive and correlational research design. METHODS: The active and passive distal transverse arches of the dominant hand of 104 healthy subjects were measured using a goniometer. Additionally, the hand arch was measured when the subjects grasped and pinched objects. These data were used to analyze the correlation with age and to calculate the u-ROM (u-ROM %) rate of the distal transversal arch. Furthermore, the u-ROM% between the ring and fifth finger components of the hand arch was compared. RESULTS: The active and passive dorsal arch angles were 135.8 (10.0°) and 169.9 (11.5°), respectively. The distal transverse arch angle tended to decline with age (active: r = -0.18, p = 0.07, 95% confidence interval = -0.36 to 0.02; passive: r = -0.40, p ≤ 0.001, 95% confidence interval = -0.55 to -0.23). The u-ROM% of the hand arch in grasping and pinching ranged from 65.5 (9.8)% to 84.6 (11.6)% and from 52.1 (7.9)% to 67.4 (9.1)%, respectively, against active and passive motions. The ring finger component was significantly higher than the fifth finger component (active: p = 0.08 to <0.001, effect size = -0.17 to -0.69; passive: p ≤ 0.001, effect size= -0.71 to -0.86). A similar trend was observed in both men and women. CONCLUSIONS: Therapists should evaluate the movement of the distal transverse arch of the injured hand in detail and consider the age, sex, and component of the hand arch when intervening.

Combining Exergy and Pinch Analysis for the Operating Mode Optimization of a Steam Turbine Cogeneration Plant in Wonji-Shoa, Ethiopia.

In this research, the simulation of an existing 31.5 MW steam power plant, providing both electricity for the national grid and hot utility for the related sugar factory, was performed by means of ProSimPlus® v. 3.7.6. The purpose of this study is to analyze the steam turbine operating parameters by means of the exergy concept with a pinch-based technique in order to assess the overall energy performance and losses that occur in the power plant. The combined pinch and exergy analysis (CPEA) initially focuses on the depiction of the hot and cold composite curves (HCCCs) of the steam cycle to evaluate the energy and exergy requirements. Based on the minimal approach temperature difference (∆Tlm) required for effective heat transfer, the exergy loss that raises the heat demand (heat duty) for power generation can be quantitatively assessed. The exergy composite curves focus on the potential for fuel saving throughout the cycle with respect to three possible operating modes and evaluates opportunities for heat pumping in the process. Well-established tools, such as balanced exergy composite curves, are used to visualize exergy losses in each process unit and utility heat exchangers. The outcome of the combined exergy-pinch analysis reveals that energy savings of up to 83.44 MW may be realized by lowering exergy destruction in the cogeneration plant according to the operating scenario.

Requirement for PINCH in skeletal myoblast differentiation.

PINCH, an adaptor of focal adhesion complex, plays essential roles in multiple cellular processes and organogenesis. Here, we ablated PINCH1 or both of PINCH1 and PINCH2 in skeletal muscle progenitors using MyoD-Cre. Double ablation of PINCH1 and PINCH2 resulted in early postnatal lethality with reduced size of skeletal muscles and detachment of diaphragm muscles from the body wall. PINCH mutant myofibers failed to undergo multinucleation and exhibited disrupted sarcomere structures. The mutant myoblasts in culture were able to adhere to newly formed myotubes but impeded in cell fusion and subsequent sarcomere genesis and cytoskeleton organization. Consistent with this, expression of integrin ß1 and some cytoskeleton proteins and phosphorylation of ERK and AKT were significantly reduced in PINCH mutants. However, N-cadherin was correctly expressed at cell adhesion sites in PINCH mutant cells, suggesting that PINCH may play a direct role in myoblast fusion. Expression of MRF4, the most highly expressed myogenic factor at late stages of myogenesis, was abolished in PINCH mutants that could contribute to observed phenotypes. In addition, mice with PINCH1 being ablated in myogenic progenitors exhibited only mild centronuclear myopathic changes, suggesting a compensatory role of PINCH2 in myogenic differentiation. Our results revealed a critical role of PINCH proteins in myogenic differentiation.

Improving the electrical properties of transparent ZnO-based thin- film transistors using MgO gate dielectric with various oxygen concentrations.

Zinc oxide (ZnO)-based thin-film transistors (TFTs) have attracted increasing attention towards flat-panel displays as alternatives to silicon-based TFTs due to their transparency to visible light. Magnesium oxide (MgO) has a wide bandgap (7.8 eV) and high dielectric constant (k). This leads to the development of TFTs using MgO as a gate oxide layer, which can significantly reduce the operating voltage. However, the electrical properties and dielectric constant of MgO are determined from the percentage of oxygen in MgO. In this study, a MgO gate-oxide was deposited on ZnO by magnetron sputtering at various oxygen concentrations (0%, 66%, and 100%) to fabricate TFTs. With an increase in the oxygen concentration, the oxygen vacancies of MgO were compensated, thereby improving the crystallinity and enhancing the dielectric constant from 6.53 to 12.9 for the oxygen concentrations of 0% and 100%. No pinch-off (saturation) behavior was observed in the TFTs with 0% oxygen; however, the pinch-off voltages were significantly reduced to 17 and 2 V in the TFTs with 66% and 100% oxygen, respectively; hence, the TFT-100 could be operated at a low operating voltage (2 V). With an increase in oxygen from 0% to 100%, the threshold voltage and trap-state density significantly decreased from -159 V and 1.6 × 1018cm-3to -31.4 V and 6.5 × 1016cm-3, respectively. The TFTs with 0% oxygen exhibited a higher field-effect mobility of 12 cm2V-1s-1due to the uncompensated oxygen vacancy in ZnO, which had a higher electron concentration. After introducing oxygen atoms, the field-effect mobility decreased to 0.16 cm2V-1s-1in the TFTs with 66% oxygen, which can be attributed to the compensated oxygen vacancy and lower electron concentration. In contrast, the field-effect mobility increased to 1.88 cm2V-1s-1for the TFTs with 100% oxygen due to the enhanced dielectric constant and crystallinity of MgO.

Investigation of grip strength, pain threshold, pain tolerance and function in smartphone users.

PURPOSE/AIM OF THE STUDY: Few studies have demonstrated the effects of smartphone use on grip strength and upper extremity function. The present study was purposed to compare smartphone users' grip/lateral pinch strength, pain threshold/tolerance and upper limb function. MATERIALS AND METHODS: A prospective cross-sectional study was conducted with 241 individuals. Participants were divided into three groups with the cut-off values of the Smartphone Addiction Scale (SAS). The Edinburgh Handedness Inventory (EHI) was used to determine the dominant side. Thumb pain threshold and tolerance were evaluated with the algometer. A hand dynamometer measured the grip and lateral pinch strength. Upper extremity functions were evaluated with the Shortened Disabilities of the Arm, Shoulder and Hand Questionnaire (Quick-DASH). RESULTS: Handgrip strength of the dominant/non-dominant extremities and Quick-DASH scores were higher in low-level smartphone users (p < 0.05). There was no significant difference between the groups on lateral pinch strength and pain threshold/tolerance (p > 0.05). Smartphone usage significantly affected dominant and non-dominant hand grip strength (Standardized ß1 = -0.15, ß2 = -0.15, p < 0.05). In addition, the smartphone use level negatively affected dominant lateral pinch strength (Standardized ß = -0.12, p = 0.05). On the other hand, smartphone use positively affected upper extremity function (Standardized ß = 0.17, p < 0.05). CONCLUSIONS: As smartphone addiction increases, standard handgrip strength and functionality decrease. Pain threshold/tolerance is not affected by smartphone use. Future studies should focus on fine motor skills to present a more comprehensive upper limb function evaluation.

Normative values for hand grip and pinch strength for 6 to 18 year-olds in Saudi Arabia.

BACKGROUND: Normative values for hand grip and pinch strength among children in Saudi Arabia has not been well established. Therefore, the main aim of this study is to establish normative values for hand grip and pinch strength in children aged 6 to 18 years in Saudi Arabia. METHODS: A cross-sectional study was conducted from different 5 regions in Saudi Arabia. Participants between the age of 6 years and 18 years old were recruited through different primary and secondary schools in Saudi Arabia. Data for age, gender, Body Mass Index, and preferred hand were collected. Hand grip strength was measured using digital hand dynamometer and the tip pinch, palmar pinch, and key pinch strength were measured using the hydraulic pinch gauge. RESULTS: A total of 616 participants included in this study (318 boys and 298 girls). Participants were stratified into 5 chronological age groups of 6-7 years, 8-9, 10-11, 12-13, 14-15, 16-17, and 18 years. The results showed an overall trend of increasing hand grip strength and pinch strength with age regardless of hand preference. Boys had significantly higher grip strength than girls in all age groups (P < 0.05). CONCLUSION: This study established normative values for hand grip and pinch strength in the healthy Saudi pediatric and adolescent population, using boys and girls aged 6 to 18. The outcomes of this study also demonstrated that gender, age, and hand preference can all have an impact on how strong a handgrip develops.

Head posture mediates the association of cognition with hand grip and pinch strength in older adults: an examination using structural equation modeling.

BACKGROUND: The association of cognition with hand grip and pinch strength has been well-recognized in older adults. The authors sought to explore: (1) associations among forward head posture (FHP), cognition, and hand grip and pinch strength in older adults; and (2) the mediator role of FHP in these pathways using structural equation modeling (SEM). METHODS: This cross-sectional study included 88 older adults (70.5% male; mean age = 68.75±3.87 years). Cognition was assessed by the Mini-Mental State Examination (MMSE), head posture by the Craniovertebral Angle (CVA) obtained from photographic analysis, hand grip strength by a handheld dynamometer, and pinch strength by a pinch meter. Using the two SEMs, a potential mediator role of the CVA was investigated. While the MMSE was addressed as an independent variable in both models, hand grip and pinch strength were addressed as dependent variables in model 1 and model 2, respectively. RESULTS: The correlations between the CVA and MMSE (r = 0.310), hand grip strength (r = 0.370), and pinch strength (r = 0.274 to 0.292) were statistically significant (p < 0.001). In addition, significant associations were found between the MMSE and hand grip and pinch strength, ranging from 0.307 to 0.380 (p < 0.001). The mediation analysis showed that the standardized total (ß = 0.41, p < 0.001) and indirect (mediated) effects (ß = 0.12, p = 0.008) of the MMSE on hand grip strength were significant in model (1) The results were similar for model (2) The standardized total (ß = 0.39, p = 0.001) and indirect effects (ß = 0.10, p = 0.026) of the MMSE on pinch strength were significant. As a partial mediator in both models, the CVA explained 29% and 26% of the total effect in models 1 and 2, respectively. CONCLUSIONS: The CVA was associated with the MMSE, hand grip strength, and pinch strength, and CVA partially mediates the association of the MMSE with grip and pinch strength in older adults, indicating that cognition had an effect on grip and pinch strength through an indirect path via head posture. This finding reveals that evaluating head posture and providing corrective therapeutic interventions as needed may be beneficial in reducing the negative impact of decreased cognition on motor functions in older adults.

Normal Values of the Second Interosseous Pinch: A Measurement of Pure Ulnar-Innervated Intrinsic Muscles of the Hand.

PURPOSE: The second palmar interosseous muscle is innervated solely by the ulnar nerve, and second palmar interosseous pinch (2IP) strength may be a good indicator of ulnar nerve motor function. The goal of this study was to describe the 2IP test and establish its normative values, stratified by age, sex, and dominance. METHODS: Volunteers were recruited to participate in this study at various community locations. Patients over the age of 18 years were eligible for this study. Demographic information on all subjects was collected. The volunteers were asked to pinch a hydraulic pinch gauge between the index and middle finger proximal phalanges with the proximal and distal interphalangeal joints flexed and without recruiting the thumb. Three 2IP measurements were taken for each hand. Descriptive statistics and analysis of covariance were performed to determine the effect of age, sex, dominance, and side on 2IP. We analyzed the 2IP strength using the 2IP test across 3 trials to determine whether it was affected by repeated testing. RESULTS: Two hundred thirty-eight patients met the inclusion criteria (45 ± 21 years, 55% women, 87% right-hand dominant). There was no statistically significant difference between dominant and nondominant hands or among the 3 trials. There was a statistically significant correlation between age and 2IP strength ranging between 0.32 and 0.44 kg. Age and sex showed a statistically significant association with 2IP strength, with patients of older age and women having weaker 2IP. CONCLUSIONS: We determined normative values for 2IP strength using a sample from a normal population. More studies are needed to validate these results. CLINICAL RELEVANCE: Second interosseous pinch strength may be a useful tool to assess ulnar nerve function.

Validity and Reliability of the Thumb Grasp and Pinch Assessment for Children After Reconstruction of Congenital Hypoplastic Thumbs.

PURPOSE: The Thumb Grasp and Pinch Assessment (T-GAP) is a new instrument for evaluating thumb use in children with congenital hypoplastic thumbs. The assessors video-record the children while they perform nine specific activities and score their grasp types using T-GAP. A high T-GAP score indicates more mature grasp patterns. The developers reported the instrument's validity and reliability for index finger pollicization. This study investigated T-GAP's validity and reliability in children with reconstructed hypoplastic thumbs. METHODS: Four hand surgeons and two hand therapists from two hospitals rated video clips of 20 Manske type II and IIIa hands twice in 17 patients who performed the T-GAP at least 1 year after opposition transfer and thumb ligament reconstruction. To investigate the validity, we calculated correlation coefficients for T-GAP scores and clinical outcomes, including thumb ROM, grip and pinch strength, and visual analog assessments of thumb function and appearance. To estimate T-GAP's inter- and intrarater reliability, we calculated intraclass correlation coefficients and their 95% confidence intervals (CIs). RESULTS: Thumb Grasp and Pinch Assessment score showed a strong linear correlation (r = 0.815-0.944) and a moderate to strong nonlinear correlation (ρ = 0.527-0.744) with visual analog scale assessments of thumb function and appearance, respectively; a moderate nonlinear correlation (ρ = 0.464) with grip strength; and a moderate nonlinear correlation (ρ = 0.541) with thumb MCP joint range of motion. The intraclass correlation coefficient for the interrater reliability was 0.892 (95% CI, 0.768-0.954) in round 1 and 0.898 (95% CI, 0.754-0.959) in round 2, and for intrarater reliability, the mean was 0.882 (95% CI, 0.785-0.980). CONCLUSIONS: Thumb Grasp and Pinch Assessment score had a moderate to strong construct validity and a moderate concurrent validity. Both inter- and intrarater reliability was strong. CLINICAL RELEVANCE: This study supports the T-GAP instrument's validity and reliability for assessing functional outcomes in congenital hypoplastic thumb reconstruction.

Dopamine D3 Receptor Modulates Akt/mTOR and ERK1/2 Pathways Differently during the Reinstatement of Cocaine-Seeking Behavior Induced by Psychological versus Physiological Stress.

Stress triggers relapses in cocaine use that engage the activity of memory-related nuclei, such as the basolateral amygdala (BLA) and dentate gyrus (DG). Preclinical research suggests that D3 receptor (D3R) antagonists may be a promising means to attenuate cocaine reward and relapse. As D3R regulates the activity of the Akt/mTOR and MEK/ERK1/2 pathways, we assessed the effects of SB-277011-A, a D3R antagonist, on the activity of these kinases during the reinstatement of cocaine-induced conditioned place preference (CPP) induced by psychological (restraint) and physiological (tail pinch) stress. Both stimuli reactivated an extinguished cocaine-CPP, but only restrained animals decreased their locomotor activity during reinstatement. Cocaine-seeking behavior reactivation was correlated with decreased p-Akt, p-mTOR, and p-ERK1/2 activation in both nuclei of restrained animals. While a D3R blockade prevented stress-induced CPP reinstatement and plasma corticosterone enhancement, SB-277011-A distinctly modulated Akt, mTOR, and ERK1/2 activation depending on the stressor and the dose used. Our data support the involvement of corticosterone in the SB-277011-A effects in restrained animals. Additionally, the ratios p-mTOR/mTOR and/or p-ERK1/2 /ERK1/2 in the BLA during stress-induced relapse seem to be related to the locomotor activity of animals receiving 48 mg/kg of the antagonist. Hence, our study indicates the D3R antagonist's efficacy to prevent stress-induced relapses in drug use through distinct modulation of Akt/mTOR and MEK/ERK1/2 pathways in memory-processing nuclei.

Effects of Tail Pinch on BDNF and trkB Expression in the Hippocampus of Roman Low- (RLA) and High-Avoidance (RHA) Rats.

In this article, we describe the effects of tail pinch (TP), a mild acute stressor, on the levels of brain-derived neurotrophic factor (BDNF) and its tyrosine kinase receptor B (trkB) proteins in the hippocampus (HC) of the outbred Roman High- (RHA) and Low-Avoidance (RLA) rats, one of the most validated genetic models for the study of fear/anxiety- and stress-related behaviors. Using Western blot (WB) and immunohistochemistry assays, we show for the first time that TP induces distinct changes in the levels of BDNF and trkB proteins in the dorsal (dHC) and ventral (vHC) HC of RHA and RLA rats. The WB assays showed that TP increases BDNF and trkB levels in the dHC of both lines but induces opposite changes in the vHC, decreasing BDNF levels in RHA rats and trkB levels in RLA rats. These results suggest that TP may enhance plastic events in the dHC and hinder them in the vHC. Immunohistochemical assays, carried out in parallel to assess the location of changes revealed by the WB, showed that, in the dHC, TP increases BDNF-like immunoreactivity (LI) in the CA2 sector of the Ammon's horn of both Roman lines and in the CA3 sector of the Ammon's horn of RLA rats while, in the dentate gyrus (DG), TP increases trkB-LI in RHA rats. In contrast, in the vHC, TP elicits only a few changes, represented by decreases of BDNF- and trkB-LI in the CA1 sector of the Ammon's horn of RHA rats. These results support the view that the genotypic/phenotypic features of the experimental subjects influence the effects of an acute stressor, even as mild as TP, on the basal BDNF/trkB signaling, leading to different changes in the dorsal and ventral subdivisions of the HC.

A human, allogeneic cortical bone screw for distal interphalangeal joint (DIP) arthrodesis: a retrospective cohort study with at least 10 months follow-up.

INTRODUCTION: The prime requisites of a good digital arthrodesis are a painless and stable union in a proper position. Arthrodesis of the distal interphalangeal joint of the fingers is not without potential complications including nonunion, malunion, and deep tissue infections. The Shark Screw® is a human, cortical bone allograft for osteosynthesis and an alternative to metal or bioabsorbable devices in orthopedics and trauma surgery. The primary hypothesis is that the fusion and complication rate, using the Shark Screw®, is at least similar to those reported in the literature, using metal or bioabsorbable screws. MATERIAL AND METHODS: This retrospective cohort study analyzes the fusion and complication rate and the patient satisfaction of distal interphalangeal joint arthrodesis of 27 fingers with the human allogeneic cortical bone screw. Complications, Disabilities of Arm, Shoulder, and Hand Questionnaire (Quick-DASH) score and Michigan Hand Outcomes Questionnaire (MHQ) score, grip and pinch strength and fusion angle were investigated. RESULTS: The mean follow-up was 23 months. At 6 weeks after surgery, fusion was obtained for all fingers. There was no surgical complication that required revision surgery. An average fusion angle of 13.6° ± 10.7° was measured. VAS pain score decreased significantly from 6.9 before surgery to 0.14 after surgery. The Quick-DASH score decreased from 10.7 to 7.8. The MHQ score improved in all sub-scores. CONCLUSION: The complication rates, using the Shark Screw® for DIP joint arthrodesis, are lower compared to the results reported in the literature for other surgical techniques. Complications related to the human allograft cortical bone screw itself were not observed. The bone screw is completely remodeled into the host bone and further hardware removal is not necessary. LEVEL OF EVIDENCE: IV.

Flexion-extension strength of the index-thumb system in Italian population. A cross-sectional study to gather normative data.

STUDY DESIGN: Cross-sectional study. INTRODUCTION: Flexion (Palmar Pinch, PP-MVC and Tip Pinch, TP-MVC) and extension (E-MVC) maximal voluntary contraction (MVC) of the index-thumb system offers a quick way to estimate the level of hands' impairment in several musculoskeletal and neurologic conditions. PURPOSE OF THE STUDY: This study established normative data of PP-MVC, TP-MVC, E-MVC in the Italian population and evaluated their correlation with hand dominance, anthropometric factors, dexterity and workload level. METHODS: In our study, 303 healthy people (150F, 153M) were recruited. Participants performed PP-MVC, TP-MVC and E-MVC tests per hand, conducted by using a pinch-gauge. T-test was used to analyze MVC means between sexes and between hands. One-way ANOVA was conducted to compare MVC means in male and female samples stratified by age (18-29, 30-44, 45-59, 60-74, +75). Spearman's correlation analysis was performed to determine anthropometric variables, dexterity and workload level effects on MVCs. RESULTS: Medium-to-large effect sizes of age were shown in the majority of tasks. The 30 to 44 years and then +75 years age groups showed the highest and the lowest values, respectively, for both sex and both hands. Men were meanly 50% stronger, and the dominant hand showed higher values (6-10%). MVC-tests correlated moderately with weight and height weakly with dexterity and workload level. CONCLUSIONS: After 30 to 44 years, hand strength declines in line with the normal process of aging that also entails muscle fibers and the reduction of daily activities in older adults. In relative terms, E-MVC showed the highest strength loss in the over 75 seconds. The difference between sexes was higher in E-MVC than in flexion MVCs. E-MVC seems to depend more on musculoskeletal architecture that differs from women to men, according to the highest correlation between E-MVC and anthropometric variables. Only high workload levels impacted hand strength. In heaviest occupations, no PP-MVCs differences were observed between hands.

Determinants of hand function in children and adolescent with Down Syndrome-A scoping review.

BACKGROUND: Down Syndrome (DS) is a genetic condition. Physical characteristics like short stature, hypotonia, small, and thick hands result in decreased grip and pinch strength and quality of fine motor tasks. PURPOSE: The purpose of this review is to summarize the evidence of upper extremity physical characteristics and its influence on hand function in DS population. STUDY DESIGN: A scoping review. METHODOLOGY: A comprehensive electronic literature search was conducted through PubMed, CINAHL, Cochrane Library. The search was limited to articles written in English and published between 2010 to 2021. Additionally, books were referred for a better understanding of the hand function in DS. The Preferred Reporting Items for Systematic Review and Meta-Analysis extension for scoping reviews (PRISMA-ScR) was adopted to develop the protocol. RESULTS: Following a detailed review of 28 articles meeting the inclusion criteria, fetuses with a diagnosis of DS are reported to have shortening of humerus on sonographic markers wherein 9% of fetuses had below 5th percentile shortening. Additionally, literature reports that during reaching there was increased trunk rotation (effect size = 0.88). DS population had 60% less grip strength, 33% less palmar pinch strength ,20% less key pinch strength and poor manual dexterity (CI = 4.5-5.5). CONCLUSION: Findings of this review concludes that physical characteristics of the upper extremity have an influence on hand function performance in children and adolescents with DS.However, only arm length and hand span have been quantified and correlated with grip strength. Further work must focus on correlation of upper extremity anthropometry and overall hand function in children and adolscents with DS.

Effect Of Texting And Handwriting On Hand-Grip And Key-Pinch Strength Among Female-Collegiate Students: Randomized Controlled Trial.

OBJECTIVE: To evaluate immediate and long-term effect of texting or handwriting on hand-grip and key-pinch strength among healthy female students. Methods: The single-blind, randomised controlled trial was conducted between February and April 2021 after approval from the ethics review committee of the College of Medical Rehabilitation Sciences, Taibah University, Saudi Arabia, and comprised female Physio Therapy students aged 19-23 years who were right-hand dominant and had normal body mass index. The subjects used smartphones and electronic gadgets for >2hrs daily, writing more than 10min/day. They were randomised using sealed envelopes into five groups. Group A practised 10min texting, group B 15min texting, group C 10min writing, group D 15min writing, and group E used the phones only for talking or watching, with no texting or writing, and was taken as the control group. Hand-grip strength and key- pinch strength were assessed one minute before starting, and within one minute after having finished the assigned hand activity. All measurements were recorded in the sitting position using a single hand-grip dynamometer. Data was analysed using SPSS 23. RESULTS: Of the 65 individuals assessed, 60(92.3%) were initially enrolled, but the study was finished by 50(83.3%) subjects with a mean age of 20.88±0.98 years and mean body mass index 20.8±2.30kg/m2. There were 12(24%) subjects in group A, 7(14%) in group B, 12(24%) in group C, 10(20%) in group D and 9(18%) in group E. The association of the time-based groups with hand-grip and key-pinch strength was not significant (p>0.05). CONCLUSIONS: Texting and handwriting did not have any significant immediate effect on hand- grip or key-pinch strength. Clinical Trial Number: (NCT04810416).

Pinch force generation during scaling by dental professionals: A systematic review.

OBJECTIVE: The objective of this review was to examine the impact of instrument designs on pinch force generation during scaling by dental professionals. METHODS: Three databases were utilized from September 2019 to November 2021 in addition to hand-searching specific journals and reference lists. Research articles that examined pinch force generation in dental professionals during scaling with manual instruments only were included. Bias was assessed in the individual articles. RESULTS: Six research articles were included with sample populations that varied from 12 to 24 participants. Four articles evaluated instrument designs in relation to pinch force generation during scaling by dental professionals. Two articles evaluated the clinicians' experience levels and the impact on pinch force generation. Results of three articles revealed instruments with large diameters and low weights produced the least amount of pinch force (p < 0.05). Additionally, two articles found instruments with a round, tapered shape produced less pinch force and instrument handles made of silicone produced higher pinch strength post-scaling (p < 0.05). One study indicated instrument designs associated with modified scaling techniques may reduce thumb and index finger pinch force (p < 0.05). CONCLUSION: The findings from this review indicate weak evidence for instrument choices to reduce pinch force during scaling. Dental professionals should consider lightweight and large diameter instruments for manual scaling. Clinicians may also want to consider round, tapered handles and instrument designs with modified scaling techniques. This systematic review further identified the need for clinical research studies with rigorous research designs that examine the ergonomic impacts of instrument designs.