Electrospun Nanofiber/Textile Supported Composite Membranes with Improved Mechanical Performance for Biomedical Applications.

Textile-supported nanocomposite as a scaffold has been extensively used in the medical field, mainly to give support to weak or harmed tissues. However, there are some challenges in fabricating the nanofiber/textile composite, i.e., suitable porous structure with defined pore size, less skin contact area, biocompatibility, and availability of degradable materials. Herein, polyamide-6 (PA) nanofibers were synthesized using needleless electrospinning with the toothed wheel as a spinneret. The electrospinning process was optimized using different process and solution parameters. In the next phase, optimized PA nanofiber membranes of optimum fiber diameter with uniform distribution and thickness were used in making nanofiber membrane-textile composite. Different textile fabrics (woven, non-woven, knitted) were developed. The optimized nanofiber membranes were combined with non-woven, woven, and knitted fabrics to make fabric-supported nanocomposite. The nanofiber/fabric composites were compared with available market woven and knitted meshes for mechanical properties, morphology, structure, and chemical interaction analysis. It was found that the tear strength of the nanofiber/woven composite was three times higher than market woven mesh, and the nanofiber/knitted composite was 2.5 times higher than market knitted mesh. The developed composite structures with woven and knitted fabric exhibited improved bursting strength (613.1 and 751.1 Kpa), tensile strength (195.76 and 227.85 N), and puncture resistance (68.76 and 57.47 N), respectively, than market available meshes. All these properties showed that PA nanofibers/textile structures could be utilized as a composite with multifunctional properties.

Robotic partial nephrectomy in the pediatric population: Cumulative experience at a large pediatric hospital.

INTRODUCTION: Robotic partial nephrectomy is a complex minimally invasive procedure that addresses the intricate anatomy of renal masses while maximizing preservation of renal function. However, while common in adults, the evolution toward these minimally invasive procedures for children has been slow due to the anticipated technical difficulties in pediatric-sized working spaces. We present our technique and our experience with pediatric robotic partial nephrectomies that were performed with our adult urology colleagues at a large free-standing children's hospital. METHODS: The video describes our technique for a robotic right-sided partial nephrectomy in a 14-month-old male patient. The video highlights several steps of the procedure including positioning and port placement, tumor resection, and renorrhaphy. RESULTS: Six pediatric patients underwent robotic partial nephrectomy with our associated adult urologic surgeons from January 2019 to January 2021. The surgical pathology revealed both benign as well as malignant diagnoses. CONCLUSION: Robotic partial nephrectomy is a feasible minimally invasive procedure in children. The collaboration with adult minimally invasive urologic surgeons with extensive adult procedural experience is recommended to avoid potential complications with this technically challenging procedure in pediatric patients. Pediatric strategies for robotic port placement are often needed to accommodate the smaller size of pediatric patients as well as tumor size.

Path Loss Model for 3.5 GHz and 5.6 GHz Bands in Cascaded Tunnel Environments.

An important and typical scenario of radio propagation in a railway or subway tunnel environment is the cascaded straight and curved tunnel. In this paper, we propose a joint path loss model for cascaded tunnels at 3.5 GHz and 5.6 GHz frequency bands. By combining the waveguide mode theory and the method of shooting and bouncing ray (SBR), it is found that the curvature of tunnels introduces an extra loss in the far-field region, which can be modeled as a linear function of the propagation distance of the signal in the curved tunnel. The channel of the cascaded straight and curved tunnel is thus characterized using the extra loss coefficient (ELC). Based on the ray-tracing (RT) method, an empirical formula between ELC and the radius of the curvature is provided for 3.5 GHz and 5.6 GHz, respectively. Finally, the accuracy of the proposed model is verified by measurement and simulation results. It is shown that the proposed model can predict path loss in cascaded tunnels with desirable accuracy and low complexity.

Design and Analysis of High-Capacity MIMO System in Line-of-Sight Communication.

The phase of the channel matrix elements has a significant impact on channel capacity in a mobile multiple-input multiple-output (MIMO) communication system, notably in line-of-sight (LoS) communication. In this paper, the general expression for the phase of the channel matrix at maximum channel capacity is determined. Moreover, the optimal antenna configuration of the 2 × 2 and 3 × 3 transceiver antenna array is realized for LoS communication, providing methods for n×n optimal antenna placement, which can be used in short-range LoS communication and non-scattering environment communication, such as coupling train communication and inter-satellite communication. Simulation results show that the 2 × 2 rectangular antenna array is more suitable for the communication of coupling trains, while the 3 × 3 circular arc antenna array is more suitable for virtual coupling trains according to antenna configurations. Moreover, the 2 × 2 antenna rectangular configuration proposed in this paper has reached the optimal channel in inter-satellite communication, which lays a foundation for the deployment of communication systems.

Analysis of LTE-M Adjacent Channel Interference in Rail Transit.

Long Term Evolution-Metro (LTE-M), as a special communication system for train control, has strict requirements on adjacent channel interference (ACI). According to the 3rd Generation Partnership Project (3GPP) protocol of the European Telecommunications Standards Institute (ETSI) standards, this paper presents the required isolation degree for LTE-M systems to resist ACI. Aiming at the scenario of leaky cable transmission and antenna transmission adopted by the underground LTE-M system of the subway, the isolation degree required for LTE-M system deployment is deduced by combining the channel description with the principle of ACI. For the coexistence of a LTE-M system and an adjacent cellular system in a subway ground scenario, the Monte-Carlo (MC) method is used to simulate several conceivable scenarios of the LTE-M system and the adjacent frequency cellular system. In addition, the throughput loss of the LTE-M system is estimated by considering signal to interference plus noise ratio (SINR). Simulation results demonstrate that adjacent frequency user equipment (UE) has negligible small interference with the LTE-M underground system when using the leaky cable radiation pattern, whereas for the LTE-M ground system, the main interference comes from the adjacent frequency UE to the LTE-M base station (BS). Finally, interference avoidance solutions are presented, which can be utilized as a reference in the design and deployment of LTE-M systems in the rail transit environment.

Role of Rituximab in miraculous cessation of ventricular tachycardia in Granulomatosis with polyangiitis: A case report.

Granulomatosis with polyangiitis (GPA) is a rare systemic disorder of unknown aetiology. The histological findings comprise necrotising granulomatous inflammation of small arteries, arterioles, and the capillaries mainly of upper and lower respiratory tract and the kidneys. However, the disease rarely involves the cardiovascular system but may manifest as pericarditis, myocarditis, coronary arteritis, valvular lesions, and severe conduction disorders. We present an interesting, unusual, and complex case of a middle-aged man who initially presented with symptoms suggestive of Wagener's granulomatosis but two years later developed malignant ventricular arrhythmias. A diagnosis of exclusive involvement of the cardiac conduction system, without overt myocarditis, was made only after ruling it out by cardiac MRI, cardiac enzymes, echo, and normal serological markers. Evidence was paired with the cessation of monomorphic ventricular tachycardia due to induction therapy with Rituximab. In this case report, we highlight one of the rarest manifestations of GPA, i.e. Ventricular tachycardia without myocarditis.

Allograft discard risk index for heart transplantation.

BACKGROUND: The numberof patients awaiting heart transplantation (HTx) substantially exceeds the number of donor hearts transplanted each year, yet nearly 65% of eligible donor hearts are discarded rather than transplanted. METHODS: Deceased organ donors listed within the UNOS Deceased Donor Database between 2010 and 2020 were reviewed. Those greater than 10 years old and consented for heart donation were included and randomly separated into training (n = 48 435) and validation (n = 24 217) cohorts. A discard risk index (DSRI) was created using the results of univariable and multivariable analyses. Discard data were assessed at DSRI value deciles, and stratum-specific likelihood ratio (SSLR) analysis and Kaplan-Meier survival function were used for mortality data. RESULTS: Factors associated with higher DSRI values included donor age > 45, LVEF, HBV-core antibodies, hypertension, and diabetes. The DSRI C-statistic was .906 in the training cohort and .904 in the validation cohort. The DSRI did not reliably predict 30-day or 1-year mortality after transplantation (C-statistic .539 and .532, respectively). CONCLUSIONS: The factors leading to heart allograft discard are not correlated to the same degree with post-transplant outcomes. This suggests that optimizing utilization of certain allografts with slightly higher risk of discard could increase the heart donor pool with limited impact on posttransplant mortality.

Core Measures for Congestive Heart Failure in a Tertiary Care Setting in Pakistan.

PURPOSE:  Heart failure presents a huge burden for individual patients and the healthcare system as a whole. This study aims to assess the adherence to these core measures as identified by the Joint Commission on Accreditation of Healthcare Organizations (JCAHO)/ American Heart Association (AHA) by physicians of Pakistan. MATERIALS AND METHODOLOGY:  We conducted a cross-sectional study in Shifa International Hospital, Islamabad, Pakistan from the period of April 2013 to April 2016. Patients with a primary diagnosis of heart failure were drawn from a coding section of hospital's record department. Data was evaluated to assess how strictly doctors were following core measures identified by JCAHO/AHA for the given diagnosis. Inclusion criteria for this study were patients ≥ 17 years of age and patients with a primary diagnosis of heart failure according to New York Heart Association (NYHA) classification. Patients with congenital anomalies and structural heart wall problems, like sarcoidosis, hemochromatosis, and amyloidosis, were excluded from the study. RESULTS:  Mean ejection fraction (EF) was found to be 27.23 ± 11.72 percent. Symptoms assessment of heart failure was done in 16/421 (3.8%) patients according to NYHA classification and in 405/421 (96.2%) patients according to outpatient-based heart failure assessment based on physician's experience other than NYHA classification. Left ventricle ejection fraction (LVEF) was assessed in 411/421 (97%) patients. Out of these, 336/411 (81.7%) patients had EF < 40%. Mean EF was found to be significantly higher in females as compared to males (p < 0.001). Three hundred and thirty-six out of 411 (81.7%) patients with EF < 40% needed angiotensin converting enzyme inhibitors (ACEi) and beta-blocker (BB) prescriptions. ACEi were prescribed only to 230/336 (68.7%) patients and 248/336 (73.8%) patients were given BB with documented contraindication to ACEi and BB in 7.36% and 17% patients, respectively. There was no significant association between gender and mean duration of hospitalization (p = 0.411). No significant association was found between EF ≤ 40% and mean duration of hospitalization (p = 0.426). CONCLUSION:  We found that symptom assessment of congestive heart failure (CHF) patients, according to NYHA guidelines, are strikingly low. Also, a significant percentage of patients who need ACEi and BB are not prescribed the required medications despite echocardiography showing low left ventricular function.