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.

Grip and pinch strength prediction models based on hand anthropometric parameters: an analytic cross-sectional study.

BACKGROUND: Hand grip strength (HGS) and pinch strength are important clinical measures for assessing the hand and overall health. OBJECTIVE: The aim of the present study is to predict HGS and pinch strength based on 1 hand anthropometry, and (2) body anthropometric parameters using machine learning. METHODS: A Secondary analysis was conducted on 542 participant aged 30-60 years from the Persian Organizational Cohort study in Mashhad University of Medical Sciences. Artificial Neural Network (ANN) were fitted as prediction model. The dataset was divided into two sets: a training set, which comprised 70% of the data, and a test set, which comprised 30% of the data. Various combinations of the hand anthropometric, demographic, and body anthropometric parameters were used to determine the most accurate model. RESULTS: The optimal HGS model, using the input of gender, body mass, and hand anthropometric parameters of length (both total length and palm), maximum width, maximum breadth, and hand shape index, achieved nearly equal accuracy to the model that incorporated all variables (RMSE = 5.23, Adjusted R2 = 0.67). As for pinch strength, gender, hand length (both total length and palm), maximum width, maximum breadth, hand shape index, hand span, and middle finger length came closest to the model incorporating all variables (RMSE = 1.20, Adjusted R2 = 0.52). CONCLUSION: This ANN model showed that hand anthropometric parameters of total length, palm length, maximum width, maximum breadth, and the hand shape index, emerge as optimal predictors for both HGS and HPS. Body anthropometric factors (e.g., body mass) play roles as predictors for HGS, whereas their influence on pinch strength appears to be less pronounced. LEVEL OF EVIDENCE: Level III (Diagnosis). TRIAL REGISTRATION: Not applicable.

Pressure Sensors for Evaluating Hand Grasp and Pinch.

This study addresses the need for highly sensitive tools to evaluate hand strength, particularly grasp and pinch strength, which are vital for diagnosing and rehabilitating conditions affecting hand function. Current devices like the Jamar dynamometer and Martin Vigorimeter, although reliable, fail to measure extremely low force or pressure values required for individuals with severe hand impairments. This research introduces a novel device, a modified Martin Vigorimeter, utilizing an ultra-soft latex chamber and differential pressure measurement to detect minute pressure changes, thus significantly enhancing sensitivity. The device offers a cost-effective solution, making advanced hand strength evaluation more accessible for clinical and research applications. Future research should validate its accuracy across diverse populations and settings, exploring its broader implications for hand rehabilitation and occupational health.

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.

The Application of Pinch Technology to a Novel Closed-Loop Spray Drying System with a Condenser and Reheater.

Spray drying is an energy-intensive process in industrial use, making energy recovery a critical focus for improving overall efficiency. This study investigates the potential of integrating heat-recovery systems, including an innovative air reheater, into a closed-loop spray-drying unit to maximise energy savings. Through detailed pinch analysis, the system achieved a very low approach temperature, averaging 3.48 K, which is significantly lower than that of conventional open-loop systems. The study quantifies the energy-recovery potential by demonstrating that the integration of heat-recovery components can reduce the external heating demand by up to 30%. This not only enhances heat-transfer efficiency but also lowers operational costs and reduces the system's environmental impact. The results suggest that closed-loop systems with air reheaters offer a scalable solution for improving energy efficiency across different industrial applications. The research highlights a new paradigm: focusing on latent energy within the system rather than adjusting individual operational variables.

Normative Data of Grip Strength and Pinch Strength in the Indian Population.

Background There is no normative study of transregional grip strength data available from India. Hence, a multicenter study is designed to obtain reference value. Materials and Methods This is a prospective observational study conducted as a part of the Indian normative data project of the Indian Society for Surgery of the Hand. The study included three participating centers: one from the northern part and two from the southern part. Certified calibrated Jamar dynamometer and Jamar pinch gauge were used to measure the grip strength, key pinch strength, tip pinch strength, and tripod pinch strength as per the guidelines of the American Society of Hand Therapists. Results A total of 1,019 volunteers in the age group of 18 to 60 years were studied. The mean grip strength in males and females was 38.18 and 24.06 kg, respectively. The mean key pinch strength was 8.52 kg in males and 5.97 kg in females. The mean tip pinch strength was 4.86 kg in males and 3.59 kg in females. The mean tripod pinch strength was 5.41 kg in males and 4.16 kg in females. Conclusions All four strengths were lower in value when compared with American and other populations. The men had more strength than women. There was no relation to hand dominance. There was a correlation for age and height but no correlation with body mass index (BMI).

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.