Clinical Outcome of Cortical Venous Thrombosis in Stroke Patients at a Tertiary Care Hospital of Southern Punjab

Objective:  This study was determined to find out the clinical Outcome of Cortical Venous Thrombosis (CVT) in Stroke patients at a Tertiary Care Hospital of Southern Punjab. Material & Methods:  A total of 100 patients with cortical venous thrombosis were included in this descriptive case series study, which was conducted at Department of Neurology, Nishtar Hospital Multan. Outcome of patients in terms of partial recovery or complete recovery, any recurrence, any complication, indication for Surgery and any disability in terms of focal deficit, prolonged hospital stay and Mortality was followed. Results:  Our study included a total of 100 patients with cortical venous thrombosis (CVT), 35 (35%) were male and 65 (65%) were female patients with their mean age was 37.69 ± 16.52 years, ranging from 20 – 83 years (51.37 ± 17.44 in males versus 30.32 ± 10.15 years for females). Headache was noted in 80%, focal deficit in 57%, nerve palsy in 30%, coma in 22% and disability was noted in 35%. Partial recovery was noted in 65%, whereas complete recovery was noted in 35% while, complications were noted in 12 (12%) of these patients with CVT. Conclusion:  Cortical venous thrombosis was more prevalent in females in their younger age groups and it was associated with poor prognosis as high frequency of partial recovery was noted in our study. Keywords:  Cortical venous thrombosis, Stroke, headache, recovery, outcome

Dynamic performance evaluation of ultrasonic composite horn for machining soft and brittle composites

Ultrasonic horn (USH) is a key component in high intensity power ultrasonic systems to enhance vibration amplitude at tool end (VATE). Due to high intensity ultrasonic operating frequency of at least , horn may be exposed to high stress levels leading to failure. The primary objective of USH design is to achieve high vibration amplification with good strength. In present research, the effect of fillet radius / roundness on ultrasonic composite horn (USCH) performance was investigated for various materials: stainless steel, aluminum, titanium, and steel, respectively, using finite element analysis (FEA). USCH was developed for ultrasonic machining of soft and brittle composites, especially Nomex honeycomb composite. The important performance parameters considered were longitudinal modal frequency (LMF), Von Mises (VM) stresses, magnification factor (MF), VATE and factor of safety (FS). LMF was found to increase, with decrease in VATE and VM stresses by increasing the roundness at the transition section. Titanium was observed to be highly appropriate material for USCH, because it delivered at least 81.6 % to 142.62 % more vibration amplification and up to 4 times higher factor of safety, consequently, operating life in comparison to other USCH materials

Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability

Real time modeling, simulation and control of dynamical systems

This book introduces modeling and simulation of linear time invariant systems and demonstrates how these translate to systems engineering, mechatronics engineering, and biomedical engineering. It is organized into nine chapters that follow the lectures used for a one-semester course on this topic, making it appropriate for students as well as researchers. The author discusses state space modeling derived from two modeling techniques and the analysis of the system and usage of modeling in control systems design. It also contains a unique chapter on multidisciplinary energy systems with a special focus on bioengineering systems and expands upon how the bond graph augments research in biomedical and bio-mechatronics systems

Asymmetrical Bipedal Modeling for Biomechanical Sit-to-Stand Movement

Non

USE OF PARABOLIC SOLAR COLLECTOR FOR MULTAN: OPTIMIZING TILT ANGLE

In Pakistan there is a growing gap between supply and demand of electricity and ever increasing &nbsp;cost per unit of fossil fuel based thermal power generation. This necessitates the need to diversify the energy-mix and increase the role of renewable energy sources like solar in the strategic planning for future. In this work, a low cost parabolic solar collector has been designed to heat water up to 150&deg; C for use in city of Multan. Its orientation and average monthly tilt angles have been estimated &amp; optimized on monthly bases. Moreover, solar radiations for the designed collector at the optimum tilt angles have been estimated. The importance of the work is that it will be helpful in disseminating the low cost indigenous solution which will help in reducing the fossil fuel import bill

Numerical evaluation of contemporary excavator bucket designs using finite element analysis

Bucket is key and primary component of heavy construction machinery such as excavators. It has to bear high impact loads during digging process, resulting in large stress and deformations. This research work has been focused on reducing stress and deformations produced in excavator bucket due to digging. For this purpose, different design patents of excavator buckets (including ornamental designs) were considered. Various models of excavator buckets were developed by varying geometrical parameters such as number of blade teeth/tips and bucket curvature. Finite element analysis of these models was carried out by using ANSYS in order to determine stress and strains. Maximum values of Von Mises stress, principal stress, factor of safety and total deformation were evaluated numerically for all three-dimensional geometric models. Excavator bucket with least values of stress and deformations, but largest factor of safety, was identified through numerical computations. Mechanical performance of ornamental buckets having quarter circular curvature with 6 blade teeth was observed to be better as compared to designs having single blade strip or 5 blade teeth. Mass reduction up to 2.5%, while the stress reduction and factor of safety enhancement up to 9.6% was achieved by incorporating 6 blade teeth in ornamental design of excavator bucket

Design of Model-Based and Model-Free Robust Control Strategies for Lower Limb Rehabilitation Exoskeletons

Rehabilitation in the form of locomotion assistance and gait training through robotic exoskeletons requires both precision and accuracy to achieve effective results. The essential challenge is to ensure robust tracking of the reference signal, i.e., of the gait or locomotion. This paper presents the design of model-based (MB) and model-free (MF) robust control strategies to achieve desired performance and robustness in terms of transient behavior and steady-state/tracking error, implementable to the locomotion assistance and gait training by exoskeletons. The dynamic responses of the exoskeleton system were investigated with both the control strategies. The study was carried out with a variety of reference signals and performance was evaluated to identify the best suited approach for rehabilitation exoskeletons. In case of the model-based control, a mathematical model of the system was developed using a bond graph modeling technique and a lead compensated H-infinity reference gain controller was designed to ensure robust tracking performance. In the model-free control strategy, however, the system function is approximated using radial basis function neural networks (RBFNNs) and an adaptive proportional-derivative RBFNN controller was designed to achieve the desired results with minimum tracking error. Both strategies make the system robust and stable. However, the MF control strategy is faster for all reference inputs as compared to the MB control strategy i.e., faster to approach the peak value and settle, and rapidly approaches the zero steady-state/tracking error. The rise time in the case of a sinusoidal input for model-free control is 0.4 s faster than the rise time in model-based control. Similarly, the settling time is 3.9 s faster in the case of model-free control, which is a prominent difference and can provide better rehabilitation results