Secondary rectal linitis plastica caused by prostatic adenocarcinoma - magnetic resonance imaging findings and dissemination pathways: A case report.

BACKGROUND: Secondary rectal linitis plastica (RLP) from prostatic adenocarcinoma is a rare and poorly understood form of metastatic spread, characterized by a desmoplastic response and concentric rectal wall infiltration with mucosal preservation. This complicates endoscopic diagnosis and can mimic gastrointestinal malignancies. This case series underscores the critical role of magnetic resonance imaging (MRI) in identifying the distinct imaging features of RLP and highlights the importance of considering this condition in the differential diagnosis of patients with a history of prostate cancer. CASE SUMMARY: Three patients with secondary RLP due to prostatic adenocarcinoma presented with varied clinical features. The first patient, a 76-year-old man with advanced prostate cancer, had rectal pain and incontinence. MRI showed diffuse prostatic invasion and significant rectal wall thickening with a characteristic "target sign" pattern. The second, a 57-year-old asymptomatic man with elevated prostate-specific antigen levels and a history of prostate cancer exhibited rectoprostatic angle involvement and rectal wall thickening on MRI, with positron emission tomography/computed tomography PSMA confirming the prostatic origin of the metastatic spread. The third patient, an 80-year-old post-radical prostatectomy, presented with refractory constipation. MRI revealed a neoplastic mass infiltrating the rectal wall. In all cases, MRI consistently showed stratified thickening, concentric signal changes, restricted diffusion, and contrast enhancement, which were essential for diagnosing secondary RLP. Biopsies confirmed the prostatic origin of the neoplastic involvement in the rectum. CONCLUSION: Recognizing MRI findings of secondary RLP is essential for accurate diagnosis and management in prostate cancer patients.

Reduced cardiovascular and metabolic responses during eccentric stepping exercise: A pilot study.

This study compared cardiovascular and metabolic responses during concentric and eccentric stepping. Eight participants (5 m, 3f; 22 ± 2 years) performed maximal concentric and eccentric ramp incremental tests on a modified stepping ergometer. Subsequently, three randomized 15-min constant-power tests were performed (1) concentric stepping at 90% of the concentric lactate threshold (LT), (2) eccentric stepping at the same power, and (3) eccentric stepping at the same oxygen uptake (V̇O2). At equivalent power (36 ± 6 W, p = 0.62), eccentric stepping resulted in 46 ± 8% lower V̇O2, 16 ± 6% lower heart rate (HR), and 11 ± 5% lower mean arterial blood pressure compared to concentric (p < 0.01). Matching V̇O2 required 65 ± 19% more power during eccentric stepping (p < 0.01). During this test, eccentric V̇O2 and HR continued to increase, resulting in a 22 ± 29% higher V̇O2 and 19 ± 16% higher HR in the final minute (p < 0.001). Reduced cardiorespiratory demand during eccentric stepping at the same power as concentric demonstrates a higher eccentric power is required to produce the same V̇O2. However, despite being below the concentric LT, eccentric V̇O2 and HR continued to increase past the predicted steady state, indicating a higher exercise intensity.

The impact of simulated 3x3 tournament on vertical jump force-time metrics in national team male basketball players.

With innovative portable force plate systems being widely implemented for lower-body neuromuscular performance assessment in an applied sports setting and the existing gap in the scientific literature regarding player performance during in-game competitive scenarios, the purpose of the present study was to compare changes in countermovement vertical jump (CVJ) performance pre-post a simulated 3×3 basketball tournament. Seven current or former members of a 3×3 national basketball team volunteered to participate in the present investigation. Upon completing standardized warm-up procedures, athletes stepped on a uni-axial force plate system sampling at 1,000 Hz and performed three maximal-effort CVJs with no arm swing. Then, the athletes proceeded to play a simulated 3×3 basketball tournament composed of two consecutive games, separated by a 15-min rest interval. Immediately following the completion of the second game, the identical CVJ testing procedures were repeated. Paired sample t-tests were used to examine pre-post-tournament differences in nineteen CVJ performance metrics (p < 0.05). The results reveal that force-time metrics during both eccentric and concentric phases of the CVJ remain relatively unchanged pre-post simulated 3×3 basketball tournament. However, multiple force-time metrics within the eccentric phase of the CVJ changed by 12.1%-19.1% (e.g., eccentric peak power and peak velocity, eccentric duration), suggesting that the eccentric phase of CVJ might be responsive to performance stimulus to a greater extent than the concentric phase. Overall, these findings further support the importance of comprehensive CVJ analysis when intending to measure changes in neuromuscular performance.

Clinical Problem-Solving: A 19-Year-Old Woman With Progressive Neurological Decline and Multiple Intracranial Lesions.

The differential diagnosis for multiple intracranial lesions in a young adult is broad and includes demyelinating, neoplastic, and infectious etiologies. In this report, we describe the case of a 19-year-old immunocompetent woman presenting with progressive headaches and aphasia. MRI of the brain revealed multiple, large supratentorial lesions with concentric bands of alternating T2 signal intensities and peripheral contrast enhancement. Cerebrospinal fluid (CSF) analysis was overall bland with negative oligoclonal bands. Serum antibody testing for neuromyelitis optica (NMO) and myelin-oligodendrocyte associated disease (MOGAD) were negative. A broad infectious work-up was also unrevealing. A definitive diagnosis was ultimately obtained after brain biopsy and the patient was started on appropriate therapy. This case highlights a diagnostic framework in evaluating immunocompetent patients presenting with multiple intracranial lesions and progressive neurological decline. The main differential diagnoses for this constellation of radiological and clinical findings are discussed and a literature review is performed on the revealed diagnosis. Lastly, both acute and long-term therapeutic approaches are reviewed.

Left Ventricular Geometric Pattern Impacts QT Dispersion in Males Athletes and Sedentary Men.

AIM: To (1) compare QT dispersion (QTd) and echocardiographic features between athletes with concentric left ventricular (LV) hypertrophy, athletes with eccentric LV hypertrophy, and sedentary controls with a normal LV geometric pattern and (2) quantify associations between QTd and echocardiographic features within these groups. METHODS: Male athletes competing in different sports and sedentary men were stratified into groups according to their LV geometric pattern. These groups included eccentric LV hypertrophy (LV index > 115 g/m2, relative wall thickness [RWT] < 0.42) consisting of 38 athletes, concentric LV hypertrophy (LV index > 115 g/m2, RWT > 0.42) consisting of 40 athletes, and normal LV geometric pattern (LV index < 115 g/m2, RWT < 0.42) consisting of 40 sedentary controls. Following a cross-sectional design, participants underwent electrocardiographic (ECG) and echocardiographic screening. Data were compared between groups using one-way analyses of variance with Bonferroni post hoc tests. Associations between corrected QTd and echocardiographic variables were quantified using Pearson correlations. RESULTS: Alongside structural disparities between groups, corrected QTd was significantly (p < 0.001) lower in athletes with eccentric LV hypertrophy compared to athletes with concentric LV hypertrophy and sedentary controls. Significant, moderate-to-very-large correlations were found between corrected QTd and interventricular septal wall thickness in athletes with concentric (r = 0.416, p = 0.008) or eccentric LV hypertrophy (r = 0.734, p < 0.001), and sedentary controls (r = 0.464, p = 0.003). CONCLUSION: The provided comparative and relationship data may inform the development of more precise approaches for ECG and echocardiographic screening in athletes, particularly in those with concentric LV hypertrophy who may be at greater risk for developing prolonged QTd.

Does the short-term learning effect impact vertical jump performance assessment on a portable force plate system?

One of the reoccurring questions that arises during the countermovement vertical jump (CVJ) assessment is whether the learning effect has an impact on the accuracy of the results obtained. Thus, the purpose of the present investigation was to examine the impact of the short-term learning effect on the assessment of lower-body neuromuscular performance characteristics when performed on a portable one-dimensional force plate system. Sixteen recreationally active college-age males volunteered to participate in the present study. Each participant completed four sets of three non-consecutive CVJs with no arm swing throughout a single day. Besides strong verbal encouragement, participants were constantly instructed to focus on pushing the ground as explosively as possible. Fourteen force-time metrics were selected for CVJ performance analysis purposes: eccentric and concentric peak and mean force and power, eccentric and concentric duration, contraction time, jump height, reactive strength index-modified, and countermovement depth. Repeated measures multivariate analysis of variance was used to examine statistically significant differences across four testing time points (p < 0.05). The results indicate an absence of any meaningful differences across four testing time points in force-time metrics of interest during both eccentric and concentric phases of the CVJ. Moreover, no differences were observed in CVJ outcome metrics such as countermovement depth, suggesting that the movement strategy tends to remain consistent. Overall, these findings reveal that CVJ test repeatability is not affected by the short-term learning effect and that data are stable at least within the scope of this study and within this population.

Change-of-Direction Performance and Its Deficits in Relation to Countermovement-Jump Height and Phase-Specific Performance Among Female Athletes.

PURPOSE: Jump and linear sprint performances both correlate with pro-agility performance. However, correlation does not imply causation, and potential confounders may affect the correlation. Therefore, this study aimed to determine the relationship between change-of-direction (COD) performance and COD deficits (COD-D) in linear-sprint and countermovement-jump (CMJ) -related performance using multiple stepwise linear-regression models. METHODS: The study included 42 female national-level intercollegiate athletes. The 10- and 20-m linear-sprint and pro-agility times, COD-D, CMJ height, and phase-specific force production and rate of force development during eccentric unloading, eccentric braking, and the concentric phases of CMJ were measured. Stepwise linear-regression analyses were used to predict the factors related to COD and COD-D. RESULTS: CMJ height was the sole predictor in the 10-m pro-agility model (adjusted R2 = .234, P = .001). Modified Reactive Strength Index (standardized coefficient, -.710) and the lowest center-of-mass depth during the CMJ (standardized coefficient, .323) were predictors in the 20-m pro-agility model (adjusted R2 = .330, P < .001). For the 10- and 20-m COD-D models, the rate of force development at 30 and 60 milliseconds, respectively, during the concentric phase was the only predictor of performance (adjusted R2 = .183, P = .003 and .237, P = .001, respectively). CONCLUSIONS: These results suggest that athletes should concentrate on improving their CMJ height, increasing their ability to lower their center of mass more deeply, and increasing their instantaneous force-production abilities immediately after the eccentric braking phase of CMJ to improve their COD performance.

Relationship between sleep quality and quantity and lower-body neuromuscular performance characteristics in semi-professional male basketball players.

Sleep has been recognized as one of the most essential recovery methods necessary for achieving optimal performance. However, there is still a lack of scientific literature focused on examining its impact on one of the most prevalent skills in the game of basketball, the countermovement vertical jump (CVJ). Therefore, the purpose of the present study was to examine the relationship between sleep quality and quantity, and lower-body neuromuscular performance characteristics within a cohort of semi-professional male basketball players. Twenty-eight athletes competing in a first-tier regional league in Serbia volunteered to participate in this investigation. Upon arrival at the gym, all athletes completed the Pittsburgh Sleep Quality Index (PSQI) self-rated questionnaire. Immediately after completion of the PSQI, each athlete stepped on a force plate system and performed three maximum-effort CVJs with no arm swing. The following force-time metrics were obtained for the analysis: eccentric and concentric absolute and relative mean and peak force and power, vertical jump height, and reactive strength index-modified. Pearson product-moment correlation coefficients were used to examine the strength of the linear relationships between sleep quality and quantity and lower-body neuromuscular performance characteristics (p < 0.05). The results indicated that sleep quality appears to have a greater impact on the concentric than the eccentric phase of the CVJ (e.g., concentric mean force [r = -0.830; p < 0.001], relative concentric peak force [r = -0.466; p = 0.013, eccentric mean power (r = -0.162; p = 0.409)], while no significant relationship was found between sleep quantity and lower-body neuromuscular performance (e.g., concentric peak force [r = -0.055; p = 0.782], relative eccentric mean power [r = -0.301; p = 0.107]). Overall, these findings offer valuable insights into the importance of good sleep hygiene (e.g., efficiency, duration) in an athletic population, and can help practitioners develop more effective training and recovery programs.

A Comparison of the Plyometric Performance of Upper Limbs between Experienced and Non-Experienced Athletes.

Although explosive upper-limb movements are far less studied than the equivalent lower-limb movements, they are important in many sports activities. The goal of this study was to explore, for the first time, the performance of street workout (SW) athletes who primarily focus on explosive and isometric strength in the upper limbs and to examine the effect of the contraction type on performance during a classical upper-body movement. Eighteen men took part in this study (age: 22.6 ± 2.1 years, height: 179.6 ± 7.1 cm, bodyweight: 71.9 ± 6.6 kg). Of these, nine practiced SW and nine practiced various team and individual sports-the latter serving as the control group. The athletes performed three different types of push-ups-one in a concentric way and two others in a plyometric way-and a fatigue-inducing push-up set. Jump heights, myoelectrical activities (through electromyography), muscle architecture, and hypertrophy (through ultrasonography) were measured. The results show no significant differences in jump height between the push-up types. Both groups confounded, but the SW athletes jumped on average 66 ± 21% higher than the control athletes (p < 0.05). There was no major difference in EMG between groups, regardless of the push-up type, but the SW athletes had a greater pectoralis major and anterior deltoid thickness as well as a greater pennation angle of the pectoralis major. The results suggest that the plyometric performance of the upper limbs does not follow the same pattern as that of the lower limbs. The SW group's greater capacity in performing explosive push-ups could be attributed to greater upper-body muscle hypertrophy and more efficient execution of the movement.

Recovery after Exercise-Induced Muscle Damage in Subjects Following a Vegetarian or Mixed Diet.

It is unclear if following a vegetarian diet affects muscle recovery after exercise-induced muscle damage (EIMD). Sixteen vegetarians (VEG) and sixteen mixed dieters (MIX) performed a vertical jump, quadriceps femoris maximal isometric, and isokinetic concentric strength tests prior to and five days following the EIMD protocol. The quadriceps muscle was injured by performing eccentric contractions. Diet: MIX consumed more g/kg of animal protein (p < 0.001) and EAA (p < 0.05) except for isoleucine. VEG consumed more plant protein (p = 0.001). Isometric strength: MIX recovered post-day 2, VEG recovered post-day 4 (group (p = 0.07), time (p < 0.001)). Concentric contractions at 60 degrees per second: Both recovered post-day 1 (group (p = 0.27), time (p = 0.05)); 180 degrees per second: MIX recovered post-day 2, VEG recovered post-day 5 (group (p = 0.10), time (p < 0.001)); and 240 degrees per second: MIX recovered post-day 1, VEG did not recover by post-day 5 (group (p = 0.01), time (p < 0.001)). Vertical jump: Both recovered post-day 3 (group (p = 0.45), time (p < 0.001)). MIX recovered isometric strength 2 days faster, concentric strength was up to 5 days faster, and soreness was 1-4 days faster when compared to VEG. Both groups had similar recovery time for power.

Soluble ST2 is a biomarker associated with left ventricular hypertrophy and concentric hypertrophy in patients with essential hypertension.

BACKGROUND: Elevated soluble stimulating factor 2 (sST2) level is observed in cardiovascular diseases, such as heart failure and acute coronary syndrome, which reflects myocardial fibrosis and hypertrophy, indicating adverse clinical outcomes. However, the association between sST2 and hypertensive heart disease are less understood. This study aimed to determine the relationship of sST2 with left ventricular hypertrophy (LVH) and geometric remodeling in essential hypertension (EH). METHODS: We enrolled 483 patients (aged 18-80 years; 51.35% female). sST2 measurements and echocardiographic analyses were performed. RESULTS: Stepwise multiple linear regression analysis showed significant associations between sST2, left ventricular (LV) mass, and LV mass index. The prevalence of LVH and concentric hypertrophy (CH) increased with higher sST2 grade levels (p for trend<0.05). Logistic regression analysis suggested that the highest tertile of sST2 was significantly associated with increased LVH risk, compared with the lowest tertile (multivariate-adjusted odds ratio [OR] of highest group: 6.61; p<0.001). Similar results were observed in the left ventricular geometric remodeling; the highest tertile of sST2 was significantly associated with increased CH risk (multivariate-adjusted OR of highest group: 5.80; p<0.001). The receiver operating characteristic analysis results revealed that sST2 had potential predictive value for LVH (area under the curve [AUC]: 0.752, 95% confidence interval [CI]: 0.704-0.800) and CH (AUC: 0.750, 95% CI: 0.699-0.802) in patients with EH. CONCLUSIONS: High sST2 level is strongly related to LVH and CH in patients with EH and can be used as a biomarker for the diagnosis and risk assessment of hypertensive heart disease.

Well-Dispersed CsPbBr3@TiO2 Heterostructure Nanocrystals from Asymmetric to Symmetric.

Metal halide perovskites (MHPs) have undergone rapid development in the fields of solar cells, light diodes, lasing, photodetectors, etc. However, the MHPs still face significant challenges, such as poor stability and heterocompositing with other functional materials at the single nanoparticle level. Herein, the successful synthesis of well-dispersed CsPbBr3@TiO2 heterostructure nanocrystals (NCs) is reported, in which each heterostructure NC has only one CsPbBr3 with a precise anatase TiO2 coating ranging from asymmetric to symmetric. Due to the protection of anatase TiO2, CsPbBr3 shows dramatically improved chemical stability and photostability. More significantly, the synthesized CsPbBr3@TiO2 heterostructure NCs form a type II heterojunction, which strongly promoted efficient photogenerated carrier separation between anatase TiO2 and CsPbBr3, hence leading to improved optoelectronic activity. This study provides a robust avenue for synthesizing stable and highly efficient MHPs@metal oxide heterostructure NCs, paving the way for the practical application of all inorganic perovskites.

Dual concentric echo sign of ultrasound in primary hyperparathyroidism: The clinical and histopathologic features and differentiation from lymph nodes.

Context: Ultrasound (US) is the most economical and widely used method for detecting lesions in parathyroid regions. Identifying typically parathyroid adenomas as hypoechoic nodules with clear margins. However, 10 % of lesions exhibit atypical features, such as the dual concentric sign, and the cognition of them still needs to be improved. Objective: To promote understanding of clinical and histopathological features for parathyroid lesions with the dual concentric echo sign and to investigate its pathogenesis and methods for distinguishing from cervical lymph nodes to improve US diagnostic accuracy. Methods: Retrospectively, patients were categorized into three groups: Group 1, with 36 patients showing parathyroid lesions with dual concentric echo signs; Group 2, with 40 patients displaying classic hypoechoic parathyroid lesions; and Group 3, comprising 36 patients with identified lymph nodes, which were all examined from January 2018 to December 2019. The clinical data on demographics, clinical symptoms, serum levels, histopathologic findings, and US image characteristics were thoroughly reviewed. Results: According to the clinical data, no significant differences in demographics or lesion sizes were observed in Group 1 and Group 2 (p > 0.05). No significant variances were noted in biochemical markers, including PTH, T-25OHD, and ALP. However, a notable difference was identified in adjusted serum calcium levels, which were significantly lower in Group 1 compared to Group 2 (p < 0.05). Additionally, the proportion of asymptomatic patients was significantly higher in Group 1 compared to Group 2 (p < 0.05). Pathological examination revealed that all lesions with dual concentric echo signs were parathyroid adenomas. The isoechoic central region predominantly corresponded to areas of loose edema, while the hypoechoic peripheral layer was primarily associated with chief and/or oncocytic cells. By comparing the ultrasonography of Groups 1 and 3, the parathyroid lesions with dual concentric echo signs exhibited significant distinctions from lymph nodes in size, blood flow classification, vascular distribution, and anatomical location (p < 0.05). Conclusion: The parathyroid lesions with dual concentric echo signs in US corresponded to specific histopathological manifestations and relatively mild clinical features in the patients, this finding may increase the likelihood of incidental detection of parathyroid lesions by US. Attention to the details of size, location, and blood flow, especially, may aid US physicians in differentiating parathyroid adenomas from cervical lymph nodes.

Fingolimod-associated Balo's concentric sclerosis in multiple sclerosis: A case report.

A report of Balo's concentric sclerosis developed alongside with fingolimod use in a patient with previously diagnosed multiple sclerosis.

A Case of Balo Concentric Sclerosis: A Multiple Sclerosis Mimic.

Balo Concentric Sclerosis (BCS) is a rare neurological demyelinating disorder similar to Multiple Sclerosis. Both present with progressive neurological debility but differences on brain imaging help with distinction. The lack of prevalence and general diagnostic information about BCS makes it an underdiagnosed disease which can sometimes delay treatment. This case of BCS was initially treated as an infectious brain mass, leading to unnecessary interventions. Early recognition and differentiation from other neurological conditions are crucial for appropriate management and prognosis. We hope that by presenting this case, we can aid in creating diagnostic criteria and promote awareness of this chronic debilitating disease.

Outcomes of Corrective, Concentric (C2) Glenoid Reaming combined with Pyrocarbon Hemiarthroplasty for B2, B3 Glenoid Arthritis.

BACKGROUND: Posterior humeral subluxation (PHS) in B2/B3 glenoid is a cause of asymmetric long-term stress on the glenoid and the potential reason for glenoid loosening in anatomic total shoulder arthroplasty (ATSA) and painful glenoid erosion in hemiarthroplasty with metallic heads (HA-Metal). We hypothesized that corrective and concentric reaming (CCR) of the glenoid associated with pyrocarbon hemiarthroplasty (HA-PYC) could improve the centering of the humeral head and decrease the risk of persistent painful glenoid erosion in young/active patients with B2/B3 glenoid. METHODS: Between 2014 and 2020, 41shoulders (in 35 patients, mean age of 57.9 years) underwent HA-PYC combined with CCR reaming for B2 (n=30) or B3 (n=11) osteoarthritis. Patients were prospectively followed with computed tomography (CT) scans performed preoperatively, immediate postoperatively and at last follow-up (> 2 years). The primary outcomes were 3D-corrected CT-scan measurements of glenoid version, PHS, progression of glenoid erosion. Secondary outcomes included functional outcome scores, return to activities, and revision rate and complications. RESULTS: At a mean follow-up of 4.5 years (2 to 9.5 years), the prosthesis survival was 95% (39/41). No patient has been reoperated for painful glenoid erosion. The mean glenoid retroversion decreased from 17.1° ± 7.5 preoperatively to 8.3° ± 8.2 at last follow-up (p=0.001), and the mean PHS from 74% to 56.5% (p=0.001) based on the scapular plane and from 59.9% to 50.3% based on the glenoid plane. The humeral head was recentered in 97% according to the glenoid surface and 71% according to the scapular plane. Correction of PHS in the scapular plane was highly correlated to correction of glenoid retroversion (p<0.001). CT-scan measurements showed that the average total medialization was 3.7 ± 3.2 mm (2.0 ± 1.8 mm due to reaming and only 1.7 ± 2.4 mm due to erosion). The Adjusted Constant score increased from 43% ± 13 to 97% ± 16 and the Subjective Shoulder Value from 38% ± 14 to 84 % ± 12 (p<0.001). Overall, 84% of active patients returned to work and all patients returned to sports. CONCLUSION: In B2/B3 glenoid arthritis, corrective, concentric glenoid reaming combined with HA-PYC improves centering of the humeral head and shows a low risk of painful glenoid erosion at mid-term follow-up. The combined procedure results in excellent functional outcomes and high prosthesis survivorship at mid-term follow-up. HA-PYC and CCR is offering an alternative shoulder arthroplasty for young/active patients with B2/B3 glenoid osteoarthritis who want to return to work or sports practice.

Eccentric exercise-induced delayed onset trunk muscle soreness alters high-density surface EMG-torque relationships and lumbar kinematics.

We aimed to assess high-density surface electromyography (HDsEMG)-torque relationships in the presence of delayed onset trunk muscle soreness (DOMS) and the effect of these relationships on torque steadiness (TS) and lumbar movement during concentric/eccentric submaximal trunk extension contractions. Twenty healthy individuals attended three laboratory sessions (24 h apart). HDsEMG signals were recorded unilaterally from the thoracolumbar erector spinae with two 64-electrode grids. HDsEMG-torque signal relationships were explored via coherence (0-5 Hz) and cross-correlation analyses. Principal component analysis was used for HDsEMG-data dimensionality reduction and improvement of HDsEMG-torque-based estimations. DOMS did not reduce either concentric or eccentric trunk extensor muscle strength. However, in the presence of DOMS, improved TS, alongside an altered HDsEMG-torque relationship and kinematic changes were observed, in a contraction-dependent manner. For eccentric trunk extension, improved TS was observed, with greater lumbar flexion movement and a reduction in δ-band HDsEMG-torque coherence and cross-correlation. For concentric trunk extensions, TS improvements were observed alongside reduced thoracolumbar sagittal movement. DOMS does not seem to impair the ability to control trunk muscle force, however, perceived soreness induced changes in lumbar movement and muscle recruitment strategies, which could alter motor performance if the exposure to pain is maintained in the long term.

Study on the Tribological Properties of Multilayer Concentric Hexagonal Laser Texturing on Rubber Surfaces of Screw Pumps.

Given the friction and drag reduction effects observed in various biological hexagonal structures in nature, a new design was implemented on the rubber surface of the stator of a submersible screw pump. This design featured a multilayer concentric hexagonal groove structure. Furthermore, a composite multilayer hexagonal structure integrating grooves and pits was also developed and applied. This study investigated the influence of groove layer number, groove depth, pit depth, and multilayer hexagonal groove texture arrangement on the rubber surface flow characteristics. Additionally, the pressure field state, the degree of influence on the oil film-bearing capacity, and the biomimetic and hydrodynamic lubrication theories were tested using the finite element analysis method. Tribological experiments were conducted on nanosecond laser-processed rubber textures under simulated liquid lubrication conditions, reflecting actual shale oil well experiments. These experiments aimed to investigate the influence of multilayer hexagonal shape parameters on the tribological characteristics of the stator-rotor friction pair of a submersible screw pump. The results indicated that with a constant overall size, a multilayer hexagonal structure with ~0.1 mm groove depth enhanced the oil film-bearing capacity, providing significant friction and drag reduction. For composite textures, a deeper pit depth within the study area enhanced the oil film-bearing capacity. Furthermore, a gradient arrangement of groove textures featuring wider outer grooves and shallower depth exhibited superior performance in terms of bearing capacity.

Contrast enhancement patterns associated with acute stroke in moyamoya disease using MR vessel wall imaging.

BACKGROUND AND PURPOSE: High-resolution magnetic resonance imaging (HR-MRI) can provide valuable insights into the histopathological characteristics of moyamoya disease (MMD). However, the patterns of vessel wall contrast enhancement have not been well established. We aimed to identify the contrast enhancement patterns of the vessel walls associated with acute cerebral infarction using HR-MRI in MMD. METHODS: In this retrospective study, we conducted genetic tests for Ring Finger Protein 213 (RNF 213) and performed HR-MRI on patients suspected of having MMD. We analyzed wall enhancement patterns including concentric, eccentric, or mixed enhancement types, and the occurrence of acute cerebral infarction in patients who simultaneously tested positive for RNF 213 and exhibited definite features of MMD on HR-MRI. RESULTS: Among 306 patients who underwent RNF 213 tests for the evaluation of MMD, 56 showed positive RNF 213, and HR-MRI was performed on 32 of them. Among the patients with acute cerebral infarction, the incidence rate was significantly higher in the group with concentric wall enhancement compared to patients without acute cerebral infarction (73.3% vs. 17.0%, p < .002). Furthermore, the incidence was notably elevated, even in patients with pure concentric wall enhancement (40.0% vs. 5.9%, p = .033). The area under the curve (AUC) for the group with any concentric wall enhancement showed a significant result of .78 (95% confidence interval [CI]: .61-.95, p = .007), whereas the predictive ability for pure concentric wall enhancement did not reach significance (AUC = .67, 95% CI: .48-.86, p = .100). CONCLUSIONS: Concentric wall enhancement was a significant predictor of acute cerebral infarction in patients with MMD.

Corrigendum: Effects of exercise treatment on functional outcome parameters in mid-portion Achilles tendinopathy: a systematic review.

[This corrects the article DOI: 10.3389/fspor.2023.1144484.].