Atomic-Scale Insights into Light Emitting Diode

In solid-state lightning, GaN-based vertical LED technology has attracted tremendous attention because its luminous efficacy has surpassed the traditional lightning technologies, even the 2014 Nobel Prize in Physics was awarded for the invention of efficient blue LEDs, which enabled eco-friendly and energy-saving white lighting sources. Despite today’s GaN-based blue VLEDs can produce IQE of 90% and EQE of 70-80%, still there exist a major challenge of efficiency droop. Nonetheless, state-of-the-art material characterization and failure analysis tools are inevitable to address that issue. In this context, although LEDs have been characterized by different microscopy techniques, they are still limited to either its semiconductor or active layer, which mainly contributes towards the IQE. This is also one of the reason that today’s LEDs IQE exceeded above 80% but EQE of 70-80% remains. Therefore, to scrutinize the efficiency droop issue, this work focused on developing a novel strategy to investigate key layers of the LED structure, which play the critical role in enhancing the EQE = IQE x LEE factors. Based on that strategy, wafer bonding, reflection, GaN-Ag interface, MQWs and top-textured layers have been systematically investigated under the powerful advanced microscopy techniques of SEM-based TKD/EDX/EBSD, AC-STEM, AFM, Raman spectroscopy, XRD, and PL. Further, based on these correlative microscopy results, optimization suggestions are given for performance enhancement in the LEDs. The objective of this doctoral research is to perform atomic-scale characterization on the VLED layers/interfaces to scrutinize their surface topography, grain morphology, chemical composition, interfacial diffusion, atomic structure and carrier localization mechanism in quest of efficiency droop and reliability issues. The outcome of this research advances in understanding LED device physics, which will facilitate standardization in its design for better smart optoelectronics products

Glycemic control with four way model approach in rural area patients

Background: It is very important to keep the Glucose levels under control continuously and without any holidays. Type 2 diabetes is increasingly common in the industrialized world. Tight glycemic control attempts to rigidly glucose control levels (A1c: 6.5% -7.0% or lower). Maintaining tight glycemic control is lifesaving. Proper counselling, proper nutrition and if regular exercise is done it can result is good glycemic control.Methods: In the present study a total of 350 diabetic patients were selected out of which only 208 participants were eligible for study. Inclusion criteria in the study were 1) Age: men and women between age group 30 years to 70 years and 2) Type 2 Diabetes mellitus with HbA1c between 8 to 10%. Exclusion criteria in the study were 1) Type 1diabetes mellitus, Pre-existing renal, hepatic or cardiac disease, Hba1c >10%. A quadriad was established between patients, personal health worker, dietician and doctor.Results: Participants had regularly followed up and were divided randomly into cases (n = 112) and controls (n = 96). Patient were followed up as per study design it was observed that at the end of 3 months period mean FBS (case group 168.2±26.4 control group 200.8±38.3 p value <0.001) , Mean PPBS (case group 204.8±53.0 control group 271.0±45.5 p value <0.001) and Mean Hba1c (case group 8.7±0.5 control group 8.9±0.6 p value .003) in cases was significantly lower than control group.at the end 6 months it was observed that the mean cholesterol, mean triglyceride, mean LDL and mean VLDL was significantly lower in the cases compared to controls.Conclusions: A systematic approach and close monitoring that increased the adherence to medication, diet, and counselling would help in better glycemic control and prevent long term complication

Influence of single and multiple dry bands on critical flashover voltage of silicone rubber outdoor insulators: simulation and experimental study

Dry band formation on the surface of outdoor insulators is one of the main reasons leading to flashover and power outages. In this paper, a dynamic arc model is proposed for single and multiple dry bands configuration to predict the critical flashover voltage for silicone rubber outdoor insulators. An arc is modelled as a time dependent impedance consisting of a Resistor Inductor Capacitor (RLC) circuit. The effect of dry band location and existence of multiple dry bands on critical flashover voltage is investigated. To validate the proposed model, experiments were conducted in a climate chamber under controlled environmental conditions on rectangular silicone rubber sheets polluted using improved solid layer method based on IEC 60,507. Tests were conducted at different dry band configurations and pollution severity levels. A good correlation was found between experimental results and simulation results. This model can provide a good foundation for the development of mathematical models for station post insulators having multiple dry and clean bands and can be used in the design and selection of outdoor insulators for polluted conditions

Outcomes of laparoscopic fundoplication.

Gastro-esophageal reflux disease (GORD) is common and a variety of surgical repair techniques have been shown to be effective. This thesis contains two randomised controlled trials and a combined data analysis of both studies to establish which techniques appear the most effective in controlling reflux. It also contains a pilot study to determine whether intraoperative manometry can predict which patients are likely to suffer from postoperative dysphagia. One hundred and three underwent partial fundoplication (Anterior or Posterior) and one hundred and twenty one patients underwent total/subtotal (Nissen or Lind) in the randomised controlled trials and 40 patients were recruited into the intraoperative manometry study. Patients were followed up for 12 months and their change in symptoms recorded. In the partial fundoplication trial, patients who underwent posterior fundoplication had better control of symptoms compared to those who underwent anterior fundoplication at the 12 month follow up point. There was no difference between the groups who underwent Nissen and Lind fundoplication. When the studies were collated, the laparoscopic total/subtotal fundoplication appears to be superior in the control of reflux when compared to the laparoscopic partial fundoplication. Intraoperative manometry may be advantageous as the study does suggest that this investigation may be useful in predicting post-operative dysphagia

Effects of temperature and water purity on germination and yield of mungbean sprouts

Mungbean (Vigna radiata L. Wilczek) is a popular pulse crop, producing protein-rich food and nitrogen-rich residues. Mungbean sprouts were grown at different temperature levels of 10, 20 and 30°C in various water purities of 30 (distilled water), 100, 400, 700 and 1000 TDS (ppm). After keeping them in the germination chamber for 72 h, the percentage of germination, stem length and yield along with proximate composition were determined. The temperature was kept as main factor and water purity as the second. The experiment was replicated four times and the data obtained were analyzed using two factorial completely randomized design. The results showed that both the factors had significant (p<0.05) effect on the germination, stem length, yield as well as proximate composition. A temperature of 30°C and water with high purity of 30 TDS resulted in high emergence (69%), stem length (3.14 cm) and yield (70.1 g) as compared to the other treatments. Minimum germination (2.1%), stem length (0.11 cm) and yield (12.11 g) were recorded in samples kept at low temperature of 10°C and water purity with 1000 TDS. The mungbean seeds showed a very low plasticity to water purity, and that they were very susceptible to water impurities. It is concluded that, to prepare sprouts from mungbeans, it is necessary to germinate mungbean seeds them in water having high purity and temperature of 30oC for maximum germination, stem length and yield

Short-Term Load Forecasting Using AMI Data

Accurate short-term load forecasting is essential for efficient operation of the power sector. Predicting load at a fine granularity such as individual households or buildings is challenging due to higher volatility and uncertainty in the load. In aggregate loads such as at grids level, the inherent stochasticity and fluctuations are averaged-out, the problem becomes substantially easier. We propose an approach for short-term load forecasting at individual consumers (households) level, called Forecasting using Matrix Factorization (FMF). FMF does not use any consumers' demographic or activity patterns information. Therefore, it can be applied to any locality with the readily available smart meters and weather data. We perform extensive experiments on three benchmark datasets and demonstrate that FMF significantly outperforms the computationally expensive state-of-the-art methods for this problem. We achieve up to 26.5% and 24.4 % improvement in RMSE over Regression Tree and Support Vector Machine, respectively and up to 36% and 73.2% improvement in MAPE over Random Forest and Long Short-Term Memory neural network, respectively

Outcome of Surgical Treatment for Lumber Disc Herniation Causing Painful Incomplete Foot-Drop

Objective:&nbsp;&nbsp;To determine the outcome of surgical treatment for lumder disc herniation causing the painful incomplete foot drop. Material and Methods:&nbsp;&nbsp;This retrospective observational study was conducted at the Department of Neurosurgery Lady Reading Hospital, Peshawar. Both Male and female patients with lumbar disc disease causing unilateral incomplete painful foot drop were included in our study. Patients with complete or painless foot drop, bilateral foot-drop, Multiple level disc prolapse, cauda equina syndrome or sciatic neuropathy due to injection injury were excluded. Patients were followed was post-operatively in terms of power in foot dorsiflexion, medical research council (MRC) grade and pain relief &nbsp;on a Visual Analogue Scale (VAS) after 1 month and then after 6 months. Results:&nbsp;Total number of patients included were 43. Age was ranging from 18 years to 54 years and mean age was 33 years. Before surgery, &nbsp;power of MRC grade 3 or less, but greater than 1 in dorsiflexion was noted in all patients. The pain was scaled using VAS. Post peratively, at 1 month follow up, the foot-drop improved to MRC grade 4 or 5 along with pain relief of ≥ 2 points on VAS in 81. 4% (n = 35) patients and at 6 month follow-up, the figure rose to 93% (n = 40). Conclusion:&nbsp;&nbsp;Lumbar disc disease can cause a debilitating foot-drop and pain. Improving or restoring a neurology early surgical intervention has proven benefits

Impact Of Missing Data Imputation On The Fairness And Accuracy Of Graph Node Classifiers

Analysis of the fairness of machine learning (ML) algorithms recently attracted many researchers' interest. Most ML methods show bias toward protected groups, which limits the applicability of ML models in many applications like crime rate prediction etc. Since the data may have missing values which, if not appropriately handled, are known to further harmfully affect fairness. Many imputation methods are proposed to deal with missing data. However, the effect of missing data imputation on fairness is not studied well. In this paper, we analyze the effect on fairness in the context of graph data (node attributes) imputation using different embedding and neural network methods. Extensive experiments on six datasets demonstrate severe fairness issues in missing data imputation under graph node classification. We also find that the choice of the imputation method affects both fairness and accuracy. Our results provide valuable insights into graph data fairness and how to handle missingness in graphs efficiently. This work also provides directions regarding theoretical studies on fairness in graph data.Comment: Accepted at IEEE International Conference on Big Data (IEEE Big Data

Source of Bleeding and Per-Operative Findings in Extradural Hematoma (Edh): A Three-Year Experience in Lady Reading Hospital Peshawar

OBJECTIVES: The purpose of this study was to analyze the main source of bleeding and operative findings in an extradural hematoma (EDH).   METHODOLOGY: This study was conducted in the Department of Neurosurgery, Lady Reading Hospital, Peshawar. The sample size of the study was analyzed through WHO sample size calculator and 300 diagnosed patients were recruited by purposive sampling technique. Ethical approval was taken from the College of Physicians and Surgeons Pakistan (CPSP) and the hospital’s ethical committee. By using the SPSS version 23.0, all the collected data were analyzed. RESULTS: The mean age of enrolled patients was 27.96±12.71 years. There were 65.7% male and 34.3% female. The most common age group was 21–30 years followed by 31 to 40 years and 11 to 20 years with the most common source of bleeding was middle meningeal artery, 39.7% of patients fall in the temporal parietal category. CONCLUSION: Middle meningeal artery is the most common source of bleeding in EDH. Therefore, proper management of this vessel is significant to avoid the chances of re-bleed and re-do surgeries.

Improvement of Headache in Patients after Occipital Extradural Hematoma (EDH) with Less Than 15 ml of Volume after Single Burr Hole Evacuation and Placement of Drain

Objective:&nbsp;&nbsp;We hypothesized that if we operate occipital extradural hematoma (EDH) having a volume less than 15 ml by single burr hole evacuation of extradural hematoma (EDH) and placement of drain without doing craniotomy then clinical status of the patients particularly headache improves. Method:&nbsp;&nbsp;An observational study of 15 patients (with presenting GCS: 8–13) was conducted on patients who were operated in Punjab Institute of Neurosciences (PINS). All patients had acute extradural hematoma less than 15 ml after a road traffic accident (RTA). The age range was 22 – 45 years. All patients were operated on within 12 hours of road traffic accident. The timing of surgery was in the range of 1-2 hours. Results:&nbsp;&nbsp;In all patients, surgery was performed by a single burr hole at the occipital region at the site of occipital EDH and the drain was placed in an extradural position. Co-morbidities in our patients were DM, polytrauma. Receiving GCS was 9 in 2 (13.33%) patients, was 13 in 10 (66.67%), was 8 in 1 (6.66%) patient and receiving GCS was 15 in 2 (13.33%) patients. All patients were assessed clinically on 5th post-operative day. It was seen headache was relieved on 5th post-operative day in all patients except 1 (6.66%) patient. Our 1 (6.66%) patients came for follow-up with the complaint of headache and vomiting which was managed conservatively. Conclusion:&nbsp;Surgery by single burr hole evacuation and placement of drain is a safe method if occipital EDH is less than 15 ml in volum