Solar canvas:Nanoscale light management for ultra-thin, semi-transparent, and colourful solar cells

This thesis provides new solutions for integrable PV by exploiting nanophotonic principles in nanoscale architectures. It shows a high degree of control over the absorption/transmission spectrum by using optical waveguiding in either nanowires (NW) or thin films. In Chapter 2, we focus on understanding the optical properties of vertically standing semiconductor NWs as promising building blocks for next generation photonics and photovoltaics. In Chapter 3, we explore in detail the potential of semiconductor NW-based solar cells as a powerful and tunable-in-design approach for wavelength-selective semi-transparent solar cells for BIPV. Optical simulations and experimental demonstration of PMDS-embedded NW arrays confirm that by changing diameter and periodicity one can engineer the absorption and transmission spectra of the NW array to provide a broad range of bright colours, semi-transparency and high PV performance. Chapter 4 focuses on ultrathin, high efficiency and flexible Si solar cells as another photonic-based solution to minimize the compromise of high conversion efficiency for aesthetics in solar cells. Here we present a new family of surface texturing, based on correlated disordered hyperuniform patterns, capable of manipulating scattering spectrum of the incident light to be efficiently coupled into the silicon slab optical modes. We experimentally demonstrate 66.5% solar light absorption in free-standing 1um c-Si layers by using these nanotextures. Finally, in Chapter 5, we combine the unique light waveguiding and absorption in vertically standing NWs with k-space engineering given by their arrangement into arrays to increase absorption in an ultra-thin tandem cell beyond the bulk limits. The photonic and design concepts presented here combined with highly-performing PV materials make the intersection between high-efficiency, flexibility, colour-tunability and transparency closer to reality

Vasopressin attenuates ischemia-reperfusion injury via reduction of oxidative stress and inhibition of mitochondrial permeability transition pore opening in rat hearts

Aim of this study was to investigate the involvement of the mitochondrial permeability transition pore (MPTP) and oxidative stress in the cardioprotective effect of vasopressin (AVP) on ischemia/reperfusion (I/R) injury. Anesthetized male wistar rats were subjected to regional 30 min ischemia and 120 min reperfusion and randomly divided into nine groups: (1) Control; saline was administered intravenously before ischemia, (2) vasopressin was administrated 10 min prior to ischemia, (3, 4) Atractyloside as MPTP opener, was injected 5 min prior to reperfusion without and with vasopressin, (5, 6) Cyclosporine A as a MPTP closer, was injected 5 min prior to reperfusion without and with vasopressin, (7) mitochondria were isolated from control group and CaCl2 was added as MPTP opener and swelling inducer, (8) isolated mitochondria from Control hearts was incubated with Cyclosporine A before adding the CaCl2 (9) CaCl2 was added to isolated mitochondria from vasopressin group. Infusion of vasopressin decreased infarct size (18.6±1.7% vs. control group 37.6±2.4%), biochemical parameters [LDH (Lactate Dehydrogenase), CK-MB (Creatine Kinase-MB) and MDA (Malondialdehyde) plasma levels, PAB (Prooxidant-antioxidant balance)] compared to control group. Atactyloside suppressed the cardioprotective effect of vasopressin (32.5±1.9% vs. 18.6±1.7%) but administration of the Cyclosporine A without and with vasopressin significantly reduced infarct size to 17.7±4% (P<0.001) and 22.7±3% (P<0.01) respectively, vs. 37.6±2.4% in control group. Also, vasopressin, similar to Cyclosporine A, led to decrease in CaCl2-induced swelling. It seems that vasopressin through antioxidant effect and MPTP inhibition has created a cardioprotection against ischemia/reperfusion injuries. © 2015 Elsevier B.V. All rights reserved

Risk factors of delayed pre-hospital treatment seeking in patients with acute coronary syndrome: A prospective study

Objectives: Despite enormous efforts in public education, treatment seeking time still remains more than optimal in patients with acute coronary syndrome. This prospective study tries to determine the risk factors of pre-hospital delay in patients with acute coronary syndrome. Methods: Descriptive data of 190 patients with diagnosis of acute coronary syndrome attending in 2 tertiary level teaching hospital emergency departments were analyzed to determine risk factors of delayed pre-hospital treatment seeking. Demographic, social and clinical characteristics of patients were obtained and they were asked to fully describe their symptoms and the actions they had done after their symptoms onset. Results: Thirty nine (20.52) of patients were arrived in emergency department in 6 h. Sex, route of transport, scene-to-hospital distance, attributing the symptoms to non-cardiac causes and outpatient physician consultation and cigarette smoking were the risk factors of delayed treatment seeking in our studied patients with acute coronary syndrome. Patients with previous history of ischemic heart disease and Coronary Care Unit admission and patients with underlying diseases like diabetes mellitus, hypertension and hyperlipidemia showed a trend to have more delayed treatment seeking behavior but not with a statistically significant difference. Patients with positive family history of acute coronary syndrome arrived in emergency department earlier than other patients but again with not a statistically significant difference. Conclusion: Most patients with acute coronary syndrome arrived in emergency department in >6 h of their symptoms onset. Sex, route of transport, scene-to-hospital distance, attributing the symptoms to non-cardiac origins, outpatient physician consultation and cigarette smoking were risk factors of delayed treatment seeking in studied patients. © 2016 The Emergency Medicine Association of Turkey

Human Attention in Image Captioning: Dataset and Analysis

This is the author accepted manuscript. The final version is available from IEE via the DOI in this record.Data availablility: The dataset can be found at: https://github.com/SenHe/ Human-Attention-in-Image-CaptioningIn this work, we present a novel dataset consisting of eye movements and verbal descriptions recorded synchronously over images. Using this data, we study the differences in human attention during free-viewing and image captioning tasks. We look into the relationship between human attention and language constructs during perception and sentence articulation. We also analyse attention deployment mechanisms in the top-down soft attention approach that is argued to mimic human attention in captioning tasks, and investigate whether visual saliency can help image captioning. Our study reveals that (1) human attention behaviour differs in free-viewing and image description tasks. Humans tend to fixate on a greater variety of regions under the latter task, (2) there is a strong relationship between described objects and attended objects (97% of the described objects are being attended), (3) a convolutional neural network as feature encoder accounts for human-attended regions during image captioning to a great extent (around 78%), (4) soft-attention mechanism differs from human attention, both spatially and temporally, and there is low correlation between caption scores and attention consistency scores. These indicate a large gap between humans and machines in regards to top-down attention, and (5) by integrating the soft attention model with image saliency, we can significantly improve the model's performance on Flickr30k and MSCOCO benchmarks.Engineering and Physical Sciences Research Council (EPSRC)Alan Turing Institut

Semi-Automated Needle Steering in Biological Tissue Using an Ultrasound-Based Deflection Predictor

The performance of needle-based interventions depends on the accuracy of needle tip positioning. Here, a novel needle steering strategy is proposed that enhances accuracy of needle steering. In our approach the surgeon is in charge of needle insertion to ensure the safety of operation, while the needle tip bevel location is robotically controlled to minimize the targeting error. The system has two main components: (1) a real-time predictor for estimating future needle deflection as it is steered inside soft tissue, and (2) an online motion planner that calculates control decisions and steers the needle toward the target by iterative optimization of the needle deflection predictions. The predictor uses the ultrasound-based curvature information to estimate the needle deflection. Given the specification of anatomical obstacles and a target from preoperative images, the motion planner uses the deflection predictions to estimate control actions, i.e., the depth(s) at which the needle should be rotated to reach the target. Ex-vivo needle insertions are performed with and without obstacle to validate our approach. The results demonstrate the needle steering strategy guides the needle to the targets with a maximum error of 1.22 mm

Lorentz Symmetry in QFT on Quantum Bianchi I Space-Time

We develop the quantum theory of a scalar field on LQC Bianchi I geometry. In particular, we focus on single modes of the field: the evolution equation is derived from the quantum scalar constraint, and it is shown that the same equation can be obtained from QFT on an "classical" effective geometry. We investigate the dependence of this effective space-time on the wavevector of the mode (which could in principle generate a deformation in local Lorentz-symmetry), focusing our attention on the dispersion relation. We prove that when we disregard backreaction no Lorentz-violation is present, despite the effective metric being different than the classical Bianchi I one. A preliminary analysis of the correction due to inclusion of backreaction is briefly discussed in the context of Born-Oppenheimer approximation.Comment: 14 pages, v3. Corrected a reference in the bibliograph

Preparation of Diltiazem Topical Gel for the Treatment of Anal Fissure and In-vitro, Ex-vivo Drug Release Evaluations

Abstract: Introduction: Anal fissures are small tears in the lining skin of the anus presenting with typical symptoms of pain and bleeding during defecation. Several new forms of medicines such as glyceryle trinitrate (GTN) ointments and diltiazem, a calcium channel-blocking agent, have been recently used for the treatment of these fissures. Diltiazem relaxes the muscle of anal sphincter and consequently increases blood flow to promote healing. It does not have GTN side effects like headache, anal burning and hypotension. The objective of this study was to formulate a suitable topical gel from diltiazem and then to investigate its physicochemical stability and also the drug release profiles from the bases. Methods: Various formulations of gel base including Guar 1.25%, Tragacanth 1.5%, HPMC 1%, and HPMC 1.5% were prepared and in vitro release and penetration characteristics of diltiazem from each preparation were studied through a hydrophilic dora pore diffusion barrier and membrane excised rat skin using Franz cell over a period of 5 hours. The amount of drug released from topical preparations was determined spectrophotometrically at ? max=236 nm. Stability studies and shelf life assessments were performed too. Results: Gel formulations containing HPMC, Guar and Tragacanth presented both good chemical and physical stabilities. The rates of cumulative drug release from HPMC 1%, HPMC 1.5%, Guar 1.25% and Tragacanth 1.5% bases using synthetic membrane were 89.7%, 76.7%, 94.9% and 66.1% respectively. For excised rat skin test, the cumulative percent of penetrated drug at the end of each experiment were 52.7 %, 50.9%, 64.6% and 42.6% for HPMC 1%, HPMC 1.5%, Guar 1.25% and Tragacanth 1.5% bases respectively. Conclusion: The comparative study showed that the percent of drug release from synthetic membrane was more than the percent of penetrated drug through excised rat skin for all bases (P<0.05). It was concluded that the kinetics of diltiazem release in vitro was not affected by the kind of gel forming agent and for all of the formulations, Higuchi’s kinetic model was suitable to explain their kinetics. Keywords: Diltiazem, Topical gel, Anal fissur

Understanding and Visualizing Deep Visual Saliency Models

This is the author accepted manuscript. The final version is available from IEEE via the DOI in this recordRecently, data-driven deep saliency models have achieved high performance and have outperformed classical saliency models, as demonstrated by results on datasets such as the MIT300 and SALICON. Yet, there remains a large gap between the performance of these models and the inter-human baseline. Some outstanding questions include what have these models learned, how and where they fail, and how they can be improved. This article attempts to answer these questions by analyzing the representations learned by individual neurons located at the intermediate layers of deep saliency models. To this end, we follow the steps of existing deep saliency models, that is borrowing a pre-trained model of object recognition to encode the visual features and learning a decoder to infer the saliency. We consider two cases when the encoder is used as a fixed feature extractor and when it is fine-tuned, and compare the inner representations of the network. To study how the learned representations depend on the task, we fine-tune the same network using the same image set but for two different tasks: saliency prediction versus scene classification. Our analyses reveal that: 1) some visual regions (e.g. head, text, symbol, vehicle) are already encoded within various layers of the network pre-trained for object recognition, 2) using modern datasets, we find that fine-tuning pre-trained models for saliency prediction makes them favor some categories (e.g. head) over some others (e.g. text), 3) although deep models of saliency outperform classical models on natural images, the converse is true for synthetic stimuli (e.g. pop-out search arrays), an evidence of significant difference between human and data-driven saliency models, and 4) we confirm that, after-fine tuning, the change in inner-representations is mostly due to the task and not the domain shift in the data.Engineering and Physical Sciences Research Council (EPSRC

Quality of life, Work ability and other important indicators of women's occupational health

Objectives: Work ability may be considered as an important aspect of well-being and health status. One of the most important factors in association with work ability is health-related quality of life (HRQoL). The aim of this study has been to determine the association between work ability, individual characteristics and HRQoL of female workers. Material and Methods: The design of this study has been cross-sectional. The work ability index (WAI) and Short-Form General Health Survey (SF-12) questionnaires were used to collect data. Three hundred and twenty female workers were selected from food supplier factories in Karaj. One-way analysis of variance, Pearson's correlation analysis, independent sample t-test and multiple linear regression methods were used to analyze data. Results: Mean (M) and standard deviation (SD) of the WAI stood at 35.02 and 5.57, respectively. The categories of the WAI for women being as follows: 8.8 poor, 62 moderate, 25.4 good and 3.7 excellent. Mean±SD for the physical component summary (PCS) and mental component summary (MCS) of quality of life was 58.84±11.12 and 57.45±9.94, respectively. There was a positive significant association between the PCS and MCS with the WAI (p = 0.0001). Workers with higher education had a better work ability (p = 0.002) and shift-work workers had a worse work ability (p = 0.03). Conclusions: Work ability of majority of women was moderate. Considering mean age of studied women (27.6 years old), this work ability is not satisfactory. Physical and mental components of the HRQoL were the important factors associated with work ability

Designing a clinical decision support system for managing and treating patients with the chief complaint of vertigo

Background: One of the challenging issues for emergency specialists is the etiology of dizziness. Using portable software installing in the mobile cell can help the clinicians to reduce the effects of confounders in emergency treatment of patients. Methods: This study was conducted in 2017 in the Department of Emergency, Rasoul-e Akram hospital, Tehran, Iran. After designing the management protocol for patients with vertigo based on the literature and standards, the validity of the protocol was approved by the expert panel. A number of 190 patients with vertigo were diagnosed using two methods for treatment and management of the disease. The first group were assessed using designed clinical decision support system, and the second group were assessed using routine method. Treatment duration, maintenance duration, and the differences between the primary and the final diagnosis were compared between the groups. Findings: Differences between the primary and the final diagnosis were significant among both groups (P < 0.050). Mean treatment duration was 3.38 and 4.96 hours in the first and second groups using support system and routine methods, respectively (P < 0.001). Mean hospitalization period was significantly shorter in support system group (9.37 hours) compared to routine method group (11.17 hours) (P < 0.001). The level of physician satisfaction with the support system was average (47.9). Conclusion: Using clinical decision support system can greatly help physicians to improve the diagnosis, decrease the hospitalization period, and manage the patients with the chief complaint of vertigo much better. © 2018, Isfahan University of Medical Sciences(IUMS). All rights reserved