Lifestyle Modifications and Dietary Factors versus Surgery in Benign Anorectal Conditions; Hemorrhoids, Fissures, and Fistulas

Benign anorectal diseases are a spectrum of conditions that involve the anus and rectum. Hemorrhoids, anal fissures, and fistulas are three of the most prevalent benign anorectal disorders that can have a detrimental impact on a patient’s quality of life

An integrated approach to simulate gas turbine secondary air system

© 2023 The American Society of Mechanical Engineers. All rights reserved.One of the most critical parts of a modern gas turbine that its reliability and performance has a great influence on cycle efficiency is the secondary air system (SAS). Modern systems functions to supply not only cooling air flow for turbine blades and vanes but sealing flow for bearing chambers and turbine segments as well as turbine disk s' purge flow in order to eliminate hot gas ingestion. Due to the various interactions between SAS and main gas, consideration of the former is substantially crucial in design and analysis of the whole engine. Geometrical complexities and centrifugal effects of rotating blades and disks, however, make the flow field and heat transfer of the problem so complicated AND too computationally costly to be simulated utilizing full 3-D CFD methods. Therefore, developing 1-D and 0-D tools applying network methods are of great interests. The present article describes a modular SAS analysis tool that is consisted of a network of elements and nodes. Each flow branch of a whole engine SAS network is substituted with an element and then, various branches (elements) intersect with each other just at their end nodes. These elements which might include some typical components such as labyrinth seals, orifices, stationary/rotating pipes, pre-swirls, and rim-seals, are generally articulated with characteristic curves that are extracted from high fidelity CFD modeling using commercial software such as Flowmaster or ANSYS-CFX. Having these curves, an algorithm is developed to calculate flow parameters at nodes with the aid of iterative methods. The procedure is based on three main innovative ideas. The first one is related to the network construction by defining a connectivity matrix which could be applied to any arbitrary network such as hydraulic or lubrication networks. In the second one, off-design SAS calculation will be proposed by introducing some SAS elements that their characteristic non-dimensional curves are influenced by their inlet total pressure. The last novelty is the integration of the blades coolant calculation process that incorporates external heat transfer calculation, structural conduction and coolant side modeling with SAS network simulation. Finally, SAS simulation of an industrial gas turbine is presented to illustrate capabilities of the presented tool in design point and off-design conditions

Analytical Modelling of Electromagnetic Bulging of Thin Metallic Tubes

© 2021 The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. This is the accepted manuscript version of a conference paper which has been published in final form at https://doi.org/10.1007/978-981-15-9505-9_70The main objective of this paper is to develop an analytical method based on the energy balance equation to model the plastic deformation of thin metallic tubes in a high velocity forming process under axisymmetric conditions. A yield criterion is proposed, which involves the coupled effect of the axial and circumferential internal force resultants. Using a combination of power-law strain hardening and strain rate hardening flow stress models, both strain hardening and strain rate effects are included. The proposed method permits consideration of the influence of different terms of kinetic energy and plastic work of the tube. The study presents a typical electromagnetic tube expansion model, using a dynamic high strain-rate forming method with strain-rates above 103 s−1. In this process, the deformation of the workpiece is achieved by the interaction of a current generated in the workpiece with a magnetic field generated by a coil adjacent to the workpiece. The results reveal that the achieved high strain rates influence the plastic flow stress and the final permanent radial deformation, consequently. The study concluded that an appropriate shape function eventuates a more accurate estimation of both the radial displacement and the deformed meridian profile

Hypertension after Bilateral Nephron Sparing Surgery for Bilateral Wilms

Background: Nephron sparing surgery (NSS) for unilateral Wilms tumor (WT) has been debated recently and is being used to preserve kidney tissue and function. However, NSS is feasible only for selected cases with higher local relapse rates. There is a significant reduction of nephrons with the development of renal hypertension and progressive renal failure. In this paper, we have analyzed outcomes after bilateral partial nephrectomy (PN) and unilateral partial plus contralateral total nephrectomy in our patients with bilateral WT.Methods: We have analyzed our four patients (8 kidneys) with bilateral WT and 8 unilateral complete resection. Kidney size was measured using volumetric analysis computed tomography scan imaging. The patients were matched with children who had undergone imaging of the abdomen for other malignancies.Results: Mean kidney volumes after unilateral partial plus total contralateral nephrectomy (60.9 cm3) were significantly greater than the reference kidneys. Total kidney volume was significantly larger after bilateral PN (98.1 cm3) versus unilateral partial plus total contralateral nephrectomy (60.9 cm3).Conclusions: Our findings suggest that patients with bilateral WT benefit from bilateral NSS. Hypertension is less common after bilateral PN. However, rates of local relapse or disease associated death are separately between the groups

Optimization of Head CT Protocol to Reduce the Absorbed Dose in Eye Lenses and Thyroid: A Phantom Study

Introduction: This study was conducted to measure the gamma emitters (e.g., uranium-238 [238U], thorium-232 [232Th], and potassium-40[40K]) and alpha emitters (e.g., radon-222 [222Rn] and radium), and also to evaluate the radiation hazard indices of radionuclides in parenteral nutrition samples utilized in the hospitals of Iraq. Material and Methods: An anthropomorphic phantom was examined with head protocols in both helical and sectional modes using two 16-slice CT scanners. The entrance surface dose of eye lenses and thyroid was measured with standard protocols and after reducing the mAS and kilo-voltage using thermo-luminescence dosimeters (TLDs). Results: In sectional mode with standard protocol, the highest surface dose was 2.3 mSv1 for eye lens and 0.021 mSv for thyroid in hospital A. Moreover, in helical mode with standard protocol, the highest surface dose was 0.964 and 0.02 mSv for eye lens and thyroid in hospital B, respectively. Reducing tube current and kilovoltage decreased the dose up to 35% for eye lens and 45% for thyroid in hospital A. By the mentioned reductions a dose decrease of up to 40% was achieved for both eye lens and thyroid in hospital B. There were no considerable differences in image quality between scans with standard protocol and the protocols of reduced parameters. Conclusion: Head CT scans with standard factors conduce to images with the best quality. It may be possible to diminish the absorbed dose up to 40% without losing information, especially in follow up head scans

Subchronic effects of different doses of Zinc oxide nanoparticle on reproductive organs of female rats: An experimental study

Background: Zinc performs many biochemical and physiological functions; however, toxicological studies demonstrate that Nano-zinc oxide has harmful effects on human health and environmental species in high concentrations. Objective: The aim of this study was to investigate the toxicity of zinc oxide nanoparticles on reproductive tissues of female rat. Materials and Methods: Eighty female Wistar adult rats weighing 180–200 gr, divided into eight groups (n= 10 in each group) including control, sham (treated with saline), and six groups injected with different doses of zinc oxide nanoparticle with 10–30 nanometer size (4, 8, 25, 50, 100, and 200 mg/kg) twice a week for four weeks. At the end of the study, the rats were bled and slaughtered; the Ovary and Uterus were taken for histopathology studies and blood samples were transferred to the laboratory for biochemical analysis. Results: Microscopic diagnoses in ovary tissue were included; increase in the corpus luteum, follicular cysts, inflammatory cells infiltration and fibrosis. Histopathological changes in ovary in a dose-dependent manner. In uterus tissue the lesions consisted; epithelial destruction, hyperplasia of endometrial glands. The Estrogen and Progesterone level in the serum of rats increased in low doses and reduced in a dose-dependent manner at high doses. Conclusion: The results of the current study proved the toxicity of zinc oxide nanoparticles on the ovary and uterus organs at high concentrations, so further investigation is needed to reduce these effects. Key words: Zinc oxide, Nanoparticles, Ovary, Uterus, Toxicity

Validity and Reliability of Bariatric Surgery Self- Management Behaviors Questionnaire in Iranian Population

Background: Bariatric surgery is the most effective intervention for treatment of severe obesity and patient’s adherence to self management behaviors are essential to reduce complications after surgery. The purpose of this study was to investigate the validity and reliability of bariatric surgery self-management behaviors questionnaire (BSSQ) in Iranian population. Methods: From December 2016 till June 2016, all obese patients who underwent laparoscopic obesity surgery in Shiraz Ghadir Mother and Child Hospitalwere were enrolled. Their demographic characteristics, BSSQ, General Adherence Scale (GAS), and the Specific Adherence Scale (SAS) questionnaires were collected. The content, structural and simultaneous validity and factor analysis were determined using GAS and SAS questionnaires. Results: According to psychometric factors including eating behaviors, fluid intake, vitamin and mineral supplement intake, fruits, vegetables, whole grain and protein intake, physical activity and dumping syndrome management, 6 factors could explain 61.5% of BSSQ. Total score of correlation matrix BSSQ with GAS and SAS were 0.36 and 0.70. For reliability, the Cronbach’s alpha coefficient was found 0.90 and Guttmann split-half coefficient was 0.78. Conclusion: BSSQ was shown to have an acceptable validity and reliability to be used for assessing the bariatric surgery self-management behaviors in Iranian population

Exploration of the Quality of Life in Iranian Morbid Obese People: A Qualitative Study

Background: Morbid obesity (body mass index≥40 kg/m2 or >35 kg/m2 with co-morbidity) is an important factor in reducing the quality of life which is influenced by the characteristics of the individual, his social, cultural, and environmental conditions; also, each disease has unique effects on it. Although most of the studies have been conducted on obesity (25>BMI>40), how to prevent it and improve life quality, there is lack of knowledge about what morbid obese people really experience about their life quality. Thus, this qualitative study aimed to explore the viewpoints of morbid obese people about life quality. Methods: In this conventional content analysis, data were collected using semi-structured interviews with 20 morbid obese patients who were referred to nutrition and obesity clinics of Shiraz and Ahvaz Jundishapur University of Medical Sciences. Purposeful sampling was processed from May 2016 to January 2017. The sampling continued until data saturation. Each interview was recorded by audio recorder and typed in the MAXQDA10 software. Data were analyzed after each interview. The meaning units were encoded and the codes were categorized. This trend continued until the main and sub-categories emerged. Results: Data analysis indicated 1835 codes, 76 sub-subcategories, 26 subcategories and 6 main categories including physical changes, psychological experiences, socio-personal dysfunction, negative body image, financial pressure, and change in the spirituality. Conclusion: Final results indicated that life quality had a special definition in morbid obesity and includes very different dimensions. This study can promote health care providers’ knowledge (nurses) for supporting obese people and improving their quality of life by community-based care approaches

Design and manufacturing challenges of a microturbine wheel

Micro gas turbine (MGT) is a core technology in many hybrid and integrated power systems to address the low-emission future aviation and decentralisation of energy generation. To achieve a high power-to-weight ratio as well as lowering the required maintenance, a new compact configuration with an air-bearing compartment was developed to build a 2 kW micro gas turbine. Designing a turbine wheel faced a multidisciplinary problem with many inputs and constraints in aerodynamic, heat transfer, strength, and manifesting aspects. To meet all requirements of these aspects, a design procedure is proposed in this paper. Since the manufacturing process affects the performance and life of the system, several processes, including casting, additive manufacturing (AM) and machining of the turbine wheel with different materials, were carried out, and the structural strength and performance of the components were investigated in this study. The prototype was tested experimentally to prove its performance and validate the concept. The cast wheel demonstrated both the required performance of 2 kW power output of the MGT in turbine inlet temperature of 1200 K and rotational speed of 170 krpm. However, the machined and additive manufactured samples for low-temperature/low-speed off-design conditions did not withstand structurally and called for a re-design or change in conditions.European Union funding: Marie Skłodowska-Curie 80160

Multi-fidelity combustor design and experimental test for a micro gas turbine system

A multi-fidelity micro combustor design approach is developed for a small-scale combined heat and power CHP system. The approach is characterised by the coupling of the developed preliminary design model using the combined method of 3D high-fidelity modelling and experimental testing. The integrated multi-physics schemes and their underlying interactions are initially provided. During the preliminary design phase, the rapid design exploration is achieved by the coupled reduced-order models, where the details of the combustion chamber layout, flow distributions, and burner geometry are defined as well as basic combustor performance. The high-fidelity modelling approach is then followed to provide insights into detailed flow and emission physics, which explores the effect of design parameters and optimises the design. The combustor is then fabricated and assembled in the MGT test bench. The experimental test is performed and indicates that the designed combustor is successfully implemented in the MGT system. The multi-physics models are then verified and validated against the test data. The details of refinement on lower-order models are given based on the insights acquired by high-fidelity methods. The shortage of conventional fossil fuels and the continued demand for energy supplies have led to the development of a micro-turbine system running renewable fuels. Numerical analysis is then carried out to assess the potential operation of biogas in terms of emission and performance. It produces less NOx emission but presents a flame stabilisation design challenge at lower methane content. The details of the strategy to address the flame stabilisation are also provided.Engineering and Physical Sciences Research Council (EPSRC): EP/T004665/