Design of a self-tunable, variable-length pendulum for harvesting energy from rotational motion

In this paper, a self-tunable energy harvester based on pendulum oscillations with a mechanical motion rectifier (MMR) system, which can convert vibration into electrical energy, is proposed. The harvester is composed of a pendulum excited by a slider-crank mechanism. The pendulum system is designed to automatically adjust its own natural frequency to match that of the imposed base excitation. Frequency adjustment in a proposed pendulum-type energy harvester is achieved by varying the length of the pendulum rod through changing the position of pendulum mass which mounted at its tip. The pendulum mass is driven by a ball screw through a stepper motor which controls the length of the pendulum automatically in accordance with the frequency of the external motion. The base motion frequency is detected by an infrared sensor. An ultrasonic distance sensor is used to detect the length of the pendulum rod and feeds this information to a microcontroller to obtain the corresponding natural frequency from a lookup table. The microcontroller calculates the frequency difference between natural frequency and excitation frequency and converts this value into a length difference through another lookup table. The microcontroller then gives instructions to drive a stepper motor through a sequence of steps to achieve the target length and keeps the device in resonance state to harvest maximum power during operation. Different time detection intervals were studied to investigate their effect on the tuning process. This study showed that the longer time intervals increase the detection accuracy for the calculation of low excitation frequency. The amount of energy consumed during the tuning process to adjust the pendulum length is presented. In this context, the consumed energy is only needed until the resonance of the device matches the excitation frequency. The harvester system was studied numerically and experimentally. Based on the findings of this work, the natural frequency of the harvester is successfully tuned below 0.7 Hz, when the length of pendulum rod is changed from 550 mm to 900 mm, generating power from 1.78 W to 4.1 W at an optimal load resistance value of 10 Ω and 3 Ω respectively at maximum excitation amplitude of 120 mm. Therefore, the proposed pendulum system can be used as an efficient harvester for producing power in low-frequency applications (< 1 Hz)

Demographics and clinical characteristics of alcohol-related admissions in a tertiary care hospital in Qatar: Does age matter?

Background: Alcohol consumption is a major cause of acute and chronic health conditions associated with comorbidities and traumatic injuries, despite its partial prohibition in some countries. Moreover, alcohol-related hospital admissions increase the burden on the healthcare system. More than 80% of the population in Qatar comprises expatriates. This study aimed to analyze the demographics and clinical characteristics of subjects with alcohol-related emergency department (ED) visits/hospitalization with respect to different age groups in a single tertiary hospital in Qatar. Methods: It is a retrospective observational study of adult patients who visited the ED at Hamad General Hospital between January 2013 and March 2015 and were screened positive for alcohol use. Collected data included sociodemographic characteristics, blood alcohol concentration (BAC), pattern of admission, previous medical history, laboratory investigations, treatment, hospital course, and mortality. Data were compared with respect to the distribution of age groups such as 55 years. Results: In total, 1506 consecutively admitted patients screened positive for alcohol use were included in the study; the majority of them were males (95.6%), non-Qatari nationals (71.1%), and aged 35-44 years (30.9%). The age groups 35-44 years and 45-54 years showed the highest median BAC ([0.24 interquartile range (IQR: 0.14-0.33)] and [0.24 (IQR: 0.13-0.33)], respectively) as compared to the other age groups (P = 0.001). The pattern of hospital admission, sociodemographic status, presence of comorbidities, laboratory investigations, and mortality showed specific age-related distribution. Particularly, young adults were more likely to have a previous ED visit due to trauma, whereas older patients' previous hospital admissions were mostly related to various underlying comorbidities. Conclusion: This study highlighted the patterns of age and clinico-epidemiological status of patients with alcohol-attributable hospital admissions. Our study showed that alcohol consumption was higher among the working-age group. Further studies are needed to investigate changes in the alcohol consumption patterns that may help plan for allocation of health resources and prevention of alcohol-related problems.qscienc

In-hospital mortality in SARS-CoV-2 stratified by gamma-glutamyl transferase levels

Background: This study investigates in-hospital mortality amongst patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its relation to serum levels of gamma-glutamyl transferase (GGT). Methods: Patients were stratified according to serum levels of gamma-glutamyl transferase (GGT) (GGT<50 IU/L or GGT≥50 IU/L). Results: A total of 802 participants were considered, amongst whom 486 had GGT<50 IU/L and a mean age of 48.1 (16.5) years, whilst 316 had GGT≥50 IU/L and a mean age of 53.8 (14.7) years. The chief sources of SARS-CoV-2 transmission were contact (366, 45.7%) and community (320, 40%). Most patients with GGT≥50 IU/L had either pneumonia (247, 78.2%) or acute respiratory distress syndrome (ARDS) (85, 26.9%), whilst those with GGT<50 IU/L had hypertension (141, 29%) or diabetes mellitus (DM) (147, 30.2%). Mortality was higher amongst patients with GGT≥50 IU/L (54, 17.1%) than amongst those with GGT<50 IU/L (29, 5.9%). More patients with GGT≥50 required high (83, 27.6%) or low (104, 34.6%) levels of oxygen, whereas most of those with GGT<50 had no requirement of oxygen (306, 71.2%). Multivariable logistic regression analysis indicated that GGT≥50 IU/L (odds ratio [OR]: 2.02, 95% confidence interval [CI]: 1.20–3.45, p=0.009), age (OR: 1.05, 95% CI: 1.03–1.07, p<0.001), hypertension (OR: 2.06, 95% CI: 1.19–3.63, p=0.011), methylprednisolone (OR: 2.96, 95% CI: 1.74–5.01, p<0.001) and fever (OR: 2.03, 95% CI: 1.15–3.68, p=0.016) were significant predictors of all-cause cumulative mortality. A Cox proportional hazards regression model (B = −0.68, SE =0.24, HR =0.51, p = 0.004) showed that patients with GGT<50 IU/L had a 0.51-times lower risk of all-cause cumulative mortality than patients with GGT≥50 IU/L. Conclusion: Higher levels of serum GGT were found to be an independent predictor of in-hospital mortality

Ferritin level : a predictor of severity and mortality in hospitalized COVID-19 patients

Introduction: This study aims to investigate in-hоsрitаl mоrtаlity in severe асute resрirаtоry syndrоme соrоnаvirus 2 раtients strаtified by serum ferritin levels. Methods: Patients were stratified based on ferritin levels (ferritin levels ≤ 1000 or >1000). Results: Approximately 89% (118) of the patients with ferritin levels > 1000 had pneumonia, and 51% (67) had hypertension. Fever (97, 73.5%) and shortness of breath (80, 61%) were two major symptoms among the patients in this group. Logistic regression analysis indicated that ferritin level (odds ratio [OR] = 0.36, 95% confidence interval [CI] = 0.21–0.62; p 1000. Conclusion: In this study, higher levels of serum ferritin were found to be an independent predictor of in-hоsрitаl mоrtаlity

In-hospital mortality in SARS-CoV-2 stratified by hemoglobin levels : a retrospective study

This study is to estimate in-hospital mortality in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) patients stratified by hemoglobin (Hb) level. Patients were stratified according to hemoglobin level into two groups, that is, Hb 100 g/L. A total of 6931 patients were included. Of these, 6377 (92%) patients had hemoglobin levels >100 g/L. The mean age was 44 ± 17 years, and 66% of the patients were males. The median length of overall hospital stay was 13 days [2; 31]. The remaining 554 (8%) patients had a hemoglobin level 100 g/L (52, 0.82%). Risk factors associated with increased mortality were determined by multi- variate analysis. The Kaplan-Meier survival analysis showed hemoglobin as a predictor of mortality. Cox proportional hazards regression coefficients for hemoglobin for the HB ≤ 100 category of hemoglobin were significant, B = 2.79, SE = 0.17, and HR = 16.34, p < 0.001. Multivariate logistic regression showed Hb < 100 g/L had a higher cumu- lative all-cause in-hospital mortality (22.4% vs. 0.8%; adjusted odds ratio [aOR], 0.33; 95% [CI]: [0.20–0.55]; p < 0.001). In this study, hemoglobin levels <100 g/L were found to be an independent predictor of in-hospital mortality

Computer applications in railway operation

One of the main goals of the railway simulation technique is the formation of a model that can be easily tested for any desired changes and modifications in infrastructure, control system, or in train operations in order to improve the network operation and its productivity. RailSys3.0 is a German railway simulation program that deals with this goal. In this paper, a railway network operation, with different suggested modifications in infrastructure, rolling stocks, and control system, using RailSys3.0, has been studied, optimized, and evaluated. The proposed simulation program (RailSys 3.0) was applied on ABO-KIR railway line in Alexandria city, as a case study, to assess the impact of changing track configuration, operating and control systems on the performance measures, time-table, track capacity and productivity. Simulation input, such as track element, train and operation components of the ABO-KIR railway line, has been entered to the computer program to construct the simulation model. The simulation process has been carried out for the existing operation system to construct a graphical model of the case-study track including line alignment and train movements, as well as to evaluate the existing operation system. To improve the operation system of the railway line, eight different innovative alternatives are generated, analyzed and evaluated. Finally, different track measures to improve the operation system of the ABO-KIR railway line have been introduced

Efficacy of combined letrozole-metformin in comparison with letrozole only in clomiphene resistant infertile women with polycystic ovarian syndrome: a randomized controlled trial

The aim of the work is to compare and determine the efficacy of combined metformin-letrozole administration in comparison with letrozole only in ovulation induction and the reproductive outcome in clomiphene – resistant infertile women with PCOS.The sample was 80 Women with PCOS and clomiphene citrate resistance. This study sample was allocated&nbsp; into two groups group (1) that received letrozole plus metformin, and group (2) that received letrozole only. All participants were followed up for 6 cycles and during this period monitoring through transvaginal ultrasonography was done every other day from day 12 of the cycle to assess follicular growth,number of follicles and endometrial thickness until at least one follicle reach 18 mm or more or reaching day 18.HCG was administered to those in whom at least one ovarian follicle reached 18 mm or more in size. The study revealed that Ovulation was 43.68 %&nbsp; in group (1) and 31.69 % in group (2) but without significant differences between both groups. pregnancy occurred in 8 women in group (1) and in 5 women in group (2) (20 % vs. 12.5 %) with no statistically significant differences between the two groups

Optimization of tannase production by Aspergillus glaucus in solid-state fermentation of black tea waste

Abstract Tannases are valuable industrial enzymes used in food, pharmaceutical, cosmetic, leather manufacture and in environmental biotechnology. In this study, 15 fungal isolates were obtained from Egyptian cultivated soil and marine samples. The isolated fungi were qualitatively and quantitatively screened for their abilities to produce tannase. The selected fungal isolate NRC8 giving highest tannase activity was identified by molecular technique (18S rRNA) as Aspergillus glaucus. Among different tannin-containing wastes tested, the black tea waste was the best substrate for tannase production by Aspergillus glaucus in solid-state fermentation (SSF). Optimization of the different process parameters required for maximum enzyme production was carried out to design a suitable SSF process. Maximal tannase production was achieved with moisture content of 75%, an inoculums size of 6 × 108 spore/ml and sodium nitrate 0.2% (pH of 5.0) at 30 °C after 5 days of incubation. Box–Behnken experiment was designed to get a quadratic model for further optimization studies. Four-factor response-surface method with 27 runs was prepared using independent parameters including (moisture content %, initial pH, substrate concentration (g) and sodium nitrate concentration (g) for tannase model. The F- and P-values of the model were 4.30 and 0.002, respectively, which implied that the model is significant. In addition, the lack-of-fit was 1040.37 which indicates the same significance relative to the pure error. A. glaucus tannase was evaluated by the efficiency of conversion of tannic acid to gallic acid. Moreover, production of gallic acid from SSF process of A. glaucus using black tea waste was found to be 38.27 mg/ml. The best bioconversion efficiency was achieved at 40 °C with tannic acid concentration up to 200 g/L. Graphical Abstrac

A Novel Approach of SWATH-Based Metabolomics Analysis Using the Human Metabolome Database Spectral Library

Metabolomics is a potential approach to paving new avenues for clinical diagnosis, molecular medicine, and therapeutic drug monitoring and development. The conventional metabolomics analysis pipeline depends on the data-independent acquisition (DIA) technique. Although powerful, it still suffers from stochastic, non-reproducible ion selection across samples. Despite the presence of different metabolomics workbenches, metabolite identification remains a tedious and time-consuming task. Consequently, sequential windowed acquisition of all theoretical MS (SWATH) acquisition has attracted much attention to overcome this limitation. This article aims to develop a novel SWATH platform for data analysis with a generation of an accurate mass spectral library for metabolite identification using SWATH acquisition. The workflow was validated using inclusion/exclusion compound lists. The false-positive identification was 3.4% from the non-endogenous drugs with 96.6% specificity. The workflow has proven to overcome background noise despite the complexity of the SWATH sample. From the Human Metabolome Database (HMDB), 1282 compounds were tested in various biological samples to demonstrate the feasibility of the workflow. The current study identified 377 compounds in positive and 303 in negative modes with 392 unique non-redundant metabolites. Finally, a free software tool, SASA, was developed to analyze SWATH-acquired samples using the proposed pipeline

Evaluation of Aspergillus tamarii NRC 3 biomass as a biosorbent for removal and recovery of heavy metals from contaminated aqueous solutions

Abstract Background Biomass produced as a byproduct from the β-mannanase production process by Aspergillus tamarii NRC 3was evaluated as a biosorbent for the removal and recovery of some heavy metal ions. Results Under optimal conditions, the isolated strain recorded the highest β-mannanase activity (31.88 Uml−1). Thus, the biomass produced from mannanase production process as a byproduct was evaluated as a biosorbent for the removal and recovery of some heavy metal ions from aqueous solutions and an industrial wastewater. The fungal biomass was found to be efficient for the removal of Cu+2 and some heavy metal ions. The biosorption process of copper(II) by Aspergillus tamarii NRC 3 biomass was affected by changing of time, temperature, pH, metal ions concentration, the presence of some heavy metals, and biomass concentration. The rate of Cu+2 uptake from Cu+2solution proceeded rapidly, and it appeared to be virtually complete during the initial 5 min (92%); the maximum uptake of Cu+2 appeared at 30 °C, pH 5, and biomass concentration 5 g w/w. On the other hand, the fungal biomass was to remove considerable proportion of Pb2+, Co+2, Ni2+, Fe+3, and Cr3+ in addition to Cu2+. The uptake of Cu+2 by pretreated biomass was studied. Recovery of the sorbed metal ions by desorbing agents and the potential reuse of the regenerated biomass in metal ions uptake (reloading) were evaluated. Conclusions Aspergillus tamarii NRC 3 biomass seems to be quite feasible in the removal of heavy metal ions especially Cu+2 from aqueous solutions