A boundary value problem of heat transfer within DBD-based plasma jet setups.

We claim an analytical solution for the thermal boundary value problem that arises in DBD-based plasma jet systems as a preliminary and consistent approach to a simplified geometry. This approach involves the outline of a coaxial plasma jet reactor and the consideration of the heat transfer to the reactor solids, namely, the dielectric barrier and the grounded electrode. The non-homogeneous initial and boundary value thermal problem is solved analytically, while a simple cut-off technique is applied to deal with the appearance of infinite series relationships, being the outcome of merging dual expressions. The results are also implemented numerically, supporting the analytical solution, while a Finite Integration Technique (FIT) is used for the validation. Both the analytical and numerical data reveal the temperature pattern at the cross-section of the solids in perfect agreement. This analytical approach could be of importance for the optimization of plasma jet systems employed in tailored applications where temperature-sensitive materials are involved, like in plasma biomedicine.

Application of the method of parallel trajectories on modeling the dynamics of COVID-19 third wave.

In this paper, we present a new method for successfully simulating the dynamics of COVID-19, experimentally focusing on the third wave. This method, namely, the Method of Parallel Trajectories (MPT), is based on the recently introduced self-organized diffusion model. According to this method, accurate simulation of the dynamics of the COVID-19 infected population evolution is accomplished by considering not the total data for the infected population, but successive segments of it. By changing the initial conditions with which each segment of the simulation is produced, we achieve close and detailed monitoring of the evolution of the pandemic, providing a tool for evaluating the overall situation and the fine-tuning of the restrictive measures. Finally, the application of the proposed MPT on simulating the pandemic's third wave dynamics in Greece and Italy is presented, verifying the method's effectiveness.

Criticality in epidemic spread: An application in the case of COVID19 infected population.

Recently, it has been successfully shown that the temporal evolution of the fraction of COVID-19 infected people possesses the same dynamics as the ones demonstrated by a self-organizing diffusion model over a lattice, in the frame of universality. In this brief, the relevant emerging dynamics are further investigated. Evidence that this nonlinear model demonstrates critical dynamics is scrutinized within the frame of the physics of critical phenomena. Additionally, the concept of criticality over the infected population fraction in epidemics (or a pandemic) is introduced and its importance is discussed, highlighting the emergence of the critical slowdown phenomenon. A simple method is proposed for estimating how far away a population is from this "singular" state, by utilizing the theory of critical phenomena. Finally, a dynamic approach applying the self-organized diffusion model is proposed, resulting in more accurate simulations, which can verify the effectiveness of restrictive measures. All the above are supported by real epidemic data case studies.

Stemless reverse total shoulder arthroplasty: a systematic review of contemporary literature.

PURPOSE: Reverse shoulder prostheses are increasingly used for treatment of rotator cuff tear arthropathy and other degenerative shoulder diseases. In recent years, aiming for bone stock preservation has led to the design of metaphyseal humeral components without a stem. The aims of this study were to evaluate the complication and reintervention rates, as well as the clinical and radiographic outcomes in patients who underwent reverse shoulder arthroplasty (RSA) with stemless implants. METHODS: A systematic review of the literature was completed until May 2020 using PubMed, EMBASE, CINAHL and Cochrane databases, according to PRISMA guidelines. RESULTS: The literature search revealed 2942 studies, of which 13 were included in this review, with a total of 517 patients and a mean follow-up between 6.4 and 101.6 months. The total complication rate was 6.5%, while 3.3% were humeral associated complications. Finally, the rate of shoulders that underwent a reintervention was 6.7%, with 1.4% relating to a humeral component reason. Stemless RSA led to substantial improvements in patient reported outcome measures and range of motion across all studies. Scapular notching was reported in 15.2%, and lucencies around humeral component were reported in 0.8% of shoulders. CONCLUSION: Stemless RSA resulted in low complication and reintervention rates at the mid-term follow-up. The reported clinical and radiological outcomes showed that these prostheses have at least equivalent outcomes with their stemmed counterparts. Further studies are required to investigate the long-term longevity and performance of the stemless humeral implants. LEVEL OF EVIDENCE: Level IV; Systematic Review.

Comparison of perfused volume segmentation between cone-beam CT and 99mTc-MAA SPECT/CT for treatment dosimetry before selective internal radiation therapy using 90Y-glass microspheres.

PURPOSE: To compare the reliability and accuracy of the pre-treatment dosimetry predictions using cone-beam computed tomography (CBCT) versus 99mTc-labeled macroaggregated albumin (MAA) SPECT/CT for perfused volume segmentation in patients with hepatocellular carcinoma treated by selective internal radiation therapy (SIRT) using 90Y-glass microspheres. MATERIALS AND METHODS: Fifteen patients (8 men, 7 women) with a mean age of 68.3±10.5 (SD) years (range: 47-82 years) who underwent a total of 17 SIRT procedures using 90Y-glass microspheres for unresectable hepatocellular carcinoma were retrospectively included. Pre-treatment dosimetry data were calculated from 99mTc-MAA SPECT/CT using either CBCT or 99mTc-MAA SPECT/CT to segment the perfused volumes. Post-treatment dosimetry data were calculated using 90Y imaging (SPECT/CT or PET/CT). The whole liver, non-tumoral liver, and tumor volumes were segmented on CT or MRI data. The mean absorbed doses of the tumor (DT), non-tumoral liver, perfused liver (DPL) and perfused non-tumoral liver were calculated. Intra- and interobserver reliabilities were investigated by calculating Lin's concordant correlation coefficients (ρc values). The differences (biases) between pre- and post-treatment dosimetry data were assessed using the modified Bland-Altman method (for non-normally distributed variables), and systematic bias was evaluated using Passing-Bablok regression. RESULTS: The intra- and interobserver reliabilities were good-to-excellent (ρc: 0.80-0.99) for all measures using both methods. Compared with 90Y imaging, the median differences were 5.8Gy (IQR: -12.7; 16.1) and 5.6Gy (IQR: -13.6; 10.2) for DPL-CBCT and DPL-99mTc-MAA SPECT/CT, respectively. The median differences were 1.6Gy (IQR: -29; 7.53) and 9.8Gy (IQR: -28.4; 19.9) for DT-CBCT and DT-99mTc-MAA SPECT/CT respectively. Passing-Bablok regression analysis showed that both CBCT and 99mTc-MAA SPECT/CT had proportional biases and thus tendencies to overestimate DT and DPL at higher post-treatment doses. CONCLUSION: CBCT may be a reliable segmentation method, but it does not significantly increase the accuracy of dose prediction compared with that of 99mTc-MAA SPECT/CT. At higher doses both methods tend to overestimate the doses to tumors and perfused livers.

Modelling the electric field in reactors yielding cold atmospheric-pressure plasma jets.

The behavior of the electric field in Cold Atmospheric-Pressure Plasma jets (CAPP jets) is important in many applications related to fundamental science and engineering, since it provides crucial information related to the characteristics of plasma. To this end, this study is focused on the analytic computation of the electric field in a standard plasma reactor system (in the absence of any space charge), considering the two principal configurations of either one-electrode or two-electrodes around a dielectric tube. The latter is considered of minor contribution to the field calculation that embodies the working gas, being an assumption for the current research. Our analytical technique employs the cylindrical geometry, properly adjusted to the plasma jet system, whereas handy subdomains separate the area of electric activity. Henceforth, we adapt the classical Maxwell's potential theory for the calculation of the electric field, wherein standard Laplace's equations are solved, supplemented by the appropriate boundary conditions and the limiting conduct at the exit of the nozzle. The theoretical approach matches the expected physics and captures the corresponding essential features in a fully three-dimensional fashion via the derivation of closed-form expressions for the related electrostatic fields as infinite series expansions of cylindrical harmonic eigenfunctions. The feasibility of our method for both cases of the described experimental setup is eventually demonstrated by efficiently incorporating the necessary numerical implementation of the obtained formulae. The analytical model is benchmarked against reported numerical results, whereas discrepancies are commented and prospective work is discussed.

Sanitary effect of FE-DBD cold plasma in ambient air on sewage biosolids.

Sewage sludge is treated by means of cold plasma and stabilization in terms of biological load deactivation is achieved. The plasma is produced by floating electrode dielectric barrier discharge operating with air under atmospheric pressure conditions. The process is presented in detail and the discharge is characterized electrically. Additionally, simulation of the thermal flow inside the process chamber is implemented, using computational fluid dynamics. Deactivation of the serotypes S. Paratyphi B., S. Livingstone, S. Mbandaka and S. Typhimurium, and Escherichia coli and Coliforms, is hereby claimed. The process involves mean electrical power in the range of tens of watts, treatment time in the scale of minutes, and maximum instantaneous temperature <400 K. The present work is a preliminary contribution towards the promotion of advanced methods for the pro-ecological management of biosolids, according to European Regulations.

Point-shear wave elastography predicts liver hypertrophy after portal vein embolization and postoperative liver failure.

PURPOSE: To correlate point-shear wave elastography (SWE) with liver hypertrophy after right portal vein embolization (RPVE) and to determine its usefulness in predicting postoperative liver failure in patients undergoing partial liver resection. PATIENTS AND METHODS: Point-SWE was performed the day before RPVE in 56 patients (41 men) with a median age of 66 years. The percentage (%) of future remnant liver (FRL) volume increase was defined as: %FRLpost-%FRLpre%FRLpre×100 and assessed on computed tomography performed 4 weeks after RPVE. RESULTS: Median (range) %FRLpre and %FRLpost was respectively, 31.5% (12-48%) and 41% (23-61%) (P<0.001), with a median %FRL volume increase of 25.6% (-8; 123%). SWE correlated with %FRL volume increase (P=-0.510; P<0.001). SWV (P=0.003) and %FRLpre (P<0.001) were associated with %FRL volume increase at multivariate regression analysis. Forty-three patients (77%) were operated. Postoperative liver failure occurred in 14 patients (32.5%). Median SWE was different between the group with (1.68m/s) and without liver failure (1.07m/s) (P=0.018). The AUROC of SWE predicting liver failure was 0.724 with a best cut-off of 1.31m/s, corresponding to a sensitivity of 21%, specificity of 96%, positive predictive value 75% and negative predictive value of 72%. SWE was the single independent preoperative variable associated with liver failure. CONCLUSIONS: SWE assessed by point-SWE is a simple and useful tool to predict the FRL volume increase and postoperative liver failure in a population of patients with liver tumor.

Acute partial passive stretching increases range of motion and muscle strength.

AIM: The purpose of this study was to investigate the effects of partial passive stretching (PPS) on peak torque (PT) and joint range of motion (ROM) in healthy subjects. METHODS: Twenty-two males (mean age 20.4±1.0 yrs, height 181.1±4.2 cm and weight 75.8±6.8 kg) participated in the study. Quadriceps and hamstrings PT at different angular velocities was obtained on an isokinetic dynamometer. Standing leg method hop was tested for the stretched and unstretched leg. Each subject performed PPS for 20 seconds. The stretching procedure was repeated 5 times for each muscle group. The whole stretching program lasted for 6 minutes and 20 seconds followed by 5 seconds resting period. RESULTS: Directly after the stretching procedure significant increases were observed of PT in quadriceps and hamstrings, however, only at 300o.s⁻¹ (P<0.05). Joint ROM was increased in all subjects (P<0.05). The distance in single length hop was increased significantly in the stretched leg following stretching (P<0.05). No changes were observed in the unstretched leg. CONCLUSION: Our results indicated that the PPS altered ROM, maximal concentric isokinetic strength at high angle velocities and single length hop only for the stretched leg. These findings suggest that PPS may be an effective technique for enhancing muscle performance.

Dynamic measurement of the force required to move a liquid drop on a solid surface.

We measured the forces required to slide sessile drops over surfaces. The forces were measured by means of a vertical deflectable capillary stuck in the drop. The drop adhesion force instrument (DAFI) allowed the investigation of the dynamic lateral adhesion force of water drops of 0.1 to 2 µL volume at defined velocities. On flat PDMS surfaces, the dynamic lateral adhesion force increases linearly with the diameter of the contact area of the solid-liquid interface and linearly with the sliding velocity. The movement of the drop relative to the surfaces enabled us to resolve the pinning of the three-phase contact line to individual defects. We further investigated a 3D superhydrophobic pillar array. The depinning of the receding part of the rim of the drop occurred almost simultaneously from four to five pillars, giving rise to peaks in the lateral adhesion force.

Ultrasound evaluation of the distal migration of the long head of biceps tendon following tenotomy in patients undergoing arthroscopic repair of tears of the rotator cuff.

This study evaluates the position of the long head of biceps tendon using ultrasound following simple tenotomy, in patients with arthroscopically repaired rotator cuff tears. In total, 52 patients with a mean age of 60.7 years (45 to 75) underwent arthroscopic repair of the rotator cuff and simple tenotomy of the long head of biceps tendon. At two years post-operatively, ultrasound revealed that the tendon was inside the bicipital groove in 43 patients (82.7%) and outside in nine (17.3%); in six of these it was lying just outside the groove and in the remaining three (5.8%) it was in a remote position with a positive Popeye Sign. A dynamic ultrasound scan revealed that the tenotomised tendons had adhered to the surrounding tissues (autotenodesis).The initial condition of the tendon influenced its final position (p < 0.0005). The presence of a Popeye sign was statistically influenced by the pre-operative co-existence of supraspinatus and subscapularis tears (p < 0.0001). It appears that the natural history of the tenotomised long head of biceps tendon is to tenodese itself inside or just outside the bicipital groove, while its pre-operative condition and coexistent subscapularis tears play a significant role in the occurrence of a Popeye sign.

Arthroscopic removal of impinging cement after unicompartmental knee arthroplasty.

Complications following unicompartmental knee arthroplasty (UKA) include aseptic loosening, polyethylene wear, arthritis progression and periprothetic fractures. We report on a patient with a firmly fixed, sizeable cement extrusion into the posteromedial aspect of the knee after a UKA causing impingement and pain in full extension. Cement extrusion is an extremely rare but potentially disabling complication that may occur despite care to remove all cement following implantation of the prosthesis. Removing a cement fragment, especially when this is firmly fixed to difficult-to-visualise and access parts of the prosthesis, is challenging. We believe the patient we report is the first one where a firmly fixed, sizeable cement extrusion was removed arthroscopically from the posterior aspect of the knee. This was achieved via an anterolateral portal with trans-notch view, combined with a posteromedial portal used both for viewing and instrument insertion. Arthroscopic removal of the impinging cement with the technique described above is a safe and effective option for the treatment of this difficult albeit rare problem.

Trastuzumab beyond progression in HER2-positive advanced breast cancer: the Royal Marsden experience.

BACKGROUND: Recent UK clinical guidance advises against continuing trastuzumab (T) beyond disease progression (PD) in the absence of brain metastases in patients with HER-2 positive (+ve) advanced breast cancer .We have retrospectively evaluated the outcome of patients with HER-2+ve locally advanced (LA) or metastatic breast cancer (MBC) who continued T beyond PD, treated in our unit. METHODS: All HER-2+ve patients on our prospectively maintained database with LA or MBC who received T beyond PD after adjuvant or one line of T for advanced disease were assessed for response and outcome. From the timepoint of T continuation beyond PD, we calculated the overall disease control rate, time to progression (TTP), and overall survival (OS). RESULTS: One hundred and fourteen patients with HER-2+ve LA or MBC treated with T beyond PD were identified. The main site of disease was visceral in 84 (74%) patients. Seventy-six (66%) had one line of chemotherapy before continuation of T beyond PD and 21 (19%) had two or more. Post-progression, 66 (58%) received T combined with chemotherapy. Of the 93 (82%) patients with documented clinical or radiological response evaluation, 67 (59%) were considered as having stable disease or better. The median TTP was 24 weeks (95% CI: 21-28) and the median OS was 19 months (95% CI: 12-24). CONCLUSION: Our results from an unselected group of patients provide additional evidence that continuation of T beyond PD is of clinical benefit.

Prostate sarcomatoid carcinoma as accidental finding in transurethral resection of prostate specimen. A case report and systematic review of current literature.

BACKGROUND: Sarcomatoid carcinoma of the prostate is an extremely rare and highly aggressive neoplasm that accounts for less than 0.1% of primary prostate malignancies. Long-term survival rates for adult patients with prostate sarcomatoid carcinoma are poor. Surgical treatment seems to be the most effective therapeutic approach. In contrast radiation therapy alone has shown limited efficacy. AIM: The purpose of the study is to present a case of sarcomatoid carcinoma of the prostate treated with a combination of radiotherapy and TURP. CASE REPORT: A 76-year-old man treated with TURP due to acute urinary retention was finally diagnosed with sarcomatoid carcinoma upon pathology examination of the surgical specimen. Patient was initially treated with external beam radiotherapy. Six months later, he presented with urinary retention suggesting extension of the tumor into the bladder neck. Pathology report diagnosed prostate sarcomatoid carcinoma containing also large areas of necrosis. Patient underwent an extensive TURP and he received a second round radiotherapy. One year after the initial diagnosis of sarcomatoid carcinoma, patient is free of symptoms and follow up investigation shows no evidence of metastatic disease. CONCLUSIONS: Radiation therapy in combination with extensive TURP may delay disease progression.

Ionic concentration- and pH-dependent electrophoretic mobility as studied by single colloid electrophoresis.

Optical tweezers are employed to measure separately the complex electrophoretic mobility of a single colloid and the complex electroosmotic response of the surrounding medium in a specially designed microfluidic cell. Using the very same colloid both quantities are determined in dependence on the concentration of the aqueous salt solution (10 (- 5)-10 (- 1) mol l (- 1)), the valence of the ions (K (+) , Ca(2 +) ) and the pH (2.5-8.5). A pronounced effect is observed for all these examined parameters. The dependence on ion concentration agrees qualitatively-for the monovalent case-with the predictions of the standard electrokinetic model.

Single colloid electrophoresis.

Optical tweezers enable one to trap a single particle without any mechanical contact and to measure its position and the forces acting on it with high resolution (+/-4 nm, +/-160 fN). Taking advantage of a specially designed microfluidic cell the electrophoretic response of the colloid under study and the electroosmotic effect on the surrounding medium are determined using the identical colloid. The former is found to be by more than one order of magnitude larger than the electroosmotic effect. It is shifted in phase with respect to the external field, hence giving rise to a complex electrophoretic mobility which can be theoretically described by a strongly damped driven harmonic oscillator model. By exchanging the medium surrounding the colloid it is possible to deduce the (KCl) concentration dependence of the single colloid electrophoretic response. The results are compared with conventional Zetasizer measurements.

Total elbow arthroplasty for the treatment of insufficient distal humeral fractures. A retrospective clinical study and review of the literature.

Treatment of complex distal humeral fractures in older patients with osteopenic bone remains a major surgical challenge. We report the results of 11 patients over 75 years of age who underwent semiconstrained sloppy-hinge total elbow arthroplasty (TEA) due to comminuted intraarticular fractures of the distal humerus. There were 9 women and 2 men with a mean age of 79.6 years. The mean duration of follow up was 2.8 years. According to AO classification, there were 8 type C3 and 3 type C2 fractures. The mean time from injury to operation was 4.3 days and the mean length of hospital stay was 9.8 days. The elbow flexion/extension and forearm pronation/supination arc of motion averaged 107(0) and 121(0) respectively. The mean Mayo Elbow Performance Score (MEPS) was 90 points, equivalent to excellent result. One patient sustained a periprosthetic humeral fracture and signs of non-progressive radiolucency were found in 8 out of the 11 elbows. Our search in the English and International literature revealed 9 other clinical studies describing the results of TEA in 167 patients with 168 distal humeral fractures. The mean age of patients varied from 69 to 84.6 years and the mean follow up from 17.8 months to 7 years. The mean MEPS among the studies was between 85 and 95 points. Wound infection was diagnosed in 9 cases (5.4%) but component removal and subsequent reimplantation was only applied in 3 elbows (1.8%). Partial ulnar nerve lesions were reported in 11 patients (6.5%) and reflex sympathetic dystrophy was developed in 5 patients (3%). In 3 elbows (1.8%) a periprosthetic fracture after a fall was recorded. Radiolucent lines between the cement mantle and bone interface were described in 24 cases (14.3%) but the majority of them (17 cases) were stable and asymptomatic. In conclusion, TEA constitutes a viable treatment option for the complex distal humeral fractures in elderly and medically compromised patients. Careful patient selection and regular follow up evaluation are mandatory for achieving an optimal result and eliminating the risks of mismanagement and early implant failure.

Temporal bone and mastoid process morphology in Mediterranean population.

The mastoid process originates from a recent phylogenetic formation and is currently considered as an evolution of the supper-structures bones. The aim of this study was the detailed description of the anatomic elements of the mastoid and the temporal bone in a large Greek adult corpse material. In total, 298 temporal bones from 149 cadaverous (74 male and 75 female) were examined from 1973 through 1993. Concerning the shape of the mastoid apex 94.0% were normal, while the rest presented several variations No statistically significant difference was revealed between genders. The diameters and axis of the temporal bone presented an independent correlation with gender in a multiple regression model. This prescription may add in easier surgical approach by adding new morphological details directly from the corpse material.

A national human neuroimaging collaboratory enabled by the Biomedical Informatics Research Network (BIRN).

The aggregation of imaging, clinical, and behavioral data from multiple independent institutions and researchers presents both a great opportunity for biomedical research as well as a formidable challenge. Many research groups have well-established data collection and analysis procedures, as well as data and metadata format requirements that are particular to that group. Moreover, the types of data and metadata collected are quite diverse, including image, physiological, and behavioral data, as well as descriptions of experimental design, and preprocessing and analysis methods. Each of these types of data utilizes a variety of software tools for collection, storage, and processing. Furthermore sites are reluctant to release control over the distribution and access to the data and the tools. To address these needs, the Biomedical Informatics Research Network (BIRN) has developed a federated and distributed infrastructure for the storage, retrieval, analysis, and documentation of biomedical imaging data. The infrastructure consists of distributed data collections hosted on dedicated storage and computational resources located at each participating site, a federated data management system and data integration environment, an Extensible Markup Language (XML) schema for data exchange, and analysis pipelines, designed to leverage both the distributed data management environment and the available grid computing resources.

Snapping knee syndrome in an athlete caused by the semitendinosus and gracilis tendons. A case report.

We report a case of symptomatic subluxation of the semitendinosus and gracilis over the posteromedial corner of the tibia manifesting with snapping. This is the first such case recorded in non-Asian population and in a high-demand athlete. Snapping was reproduced on active extension of the knee and at initiation of flexion and could be readily palpated over the posteromedial aspect of the tibia. Dynamic ultrasound, a key diagnostic tool in such conditions, revealed abrupt anterior subluxation of the semitendinosus and gracilis tendons during active terminal extension over the insertion of the semimembranosus as well as areas of tendinopathy corresponding with the site of subluxation. Due to failure of conservative treatment, surgery was undertaken, involving tenotomy and resection of a 10-12 cm segment of the semitendinosus and gracilis. The patient returned to the same level of sporting activities within 4 months and remained symptom-free 18 months post-operatively. The role of eccentric loading of the knee joint, as well as the "protective" role of the accessory tendinous bands and aponeurotic expansions of the semitendinosus and gracilis is discussed.