Parameter optimization and active vibration suppression control in gyroscopic system

A new method for suppressing vibration in a rotating beam system of a helicopter is presented. The method uses a non-linear dynamics equation to compute actual natural frequencies using FFT, not based on nominal natural frequencies of linear dynamics. A design based on linear coupling may not take account of the effect of non-linear coupling in the system, so a conceptual controller design is also presented, and a detailed control algorithm is developed. In fact, this is a non-linear dynamics optimization problem.In a gyroscopic system, tuning of the flywheel allows a commensurable relationship to be established between the natural frequencies of the system, resulting in a strong coupling between the vibrating modes. Having established a strong coupling within the system, damping is introduced in the flywheel via an actuator, resulting in rapid vibration suppression. Numerical simulation demonstrates the efficiency of the modification

Effect Of Smoking On Thyroid Status In Depression

Research Problem: Whal is Ihe impact of smoking cigarettes on thyroid functions in depression patients. Objective: To estimate T3, T4 and TSH in depressed smokers. Study Design:   Hospital   based clinical  study. Setting: Psychiatry out - door patients. Participants: Depression patients with or without history of smoking. Sample Size:     Twenty five  patients  of depression. Study Variables: Smoking, Non - smoking, T3 , T4 , TSH Statistical Analysis: Student t- test. Result: The patients of both the study group and control group had subnormal T3 but in smokers it was significantly lower than in non - smoker patients. T4 was within the normal range in both the groups, but it was significantly higher in smokers. TSH levels were normal in both the groups of patients and there was no significant difference between the two groups. Conclusion: A low T3 state exists in depression with further worsening of the condition in depressed patients who smoke, which might have an impact on therapeutic outcome. Therefore, avoidance of smoking in depression patients is suggeste

Patients\u27 perceptions of blood transfusion risks in Karachi, Pakistan

Objective: To evaluate the understanding of and attitudes toward risks of blood transfusions among transfusion recipients in Karachi.Methods: One hundred forty-one transfusion recipients from 13 major Karachi hospitals were interviewed. Indications for transfusion were obtained by reviewing the patients\u27 medical records.Results: The most common indications for transfusion were surgical complications (n = 77, 55%), anemia (n = 34, 24%), and generalized weakness (n = 15, 11%). Most recipients (n = 103, 80%) had never heard of viral hepatitis, and 44 (31%) had never heard of acquired immunodeficiency syndrome (AIDS). Ninety-four recipients (66%) believed that generalized weakness was a valid indication for blood transfusion. Sixty-nine recipients (49%) were not willing to pay an increased price for blood that was screened for blood-borne pathogens.CONCLUSIONS: Blood recipients in Karachi are unaware of the risks of transfusions, and the reasons given by the ordering physician for many of the transfusions were not consistent with international guidelines. Steps to educate the public about the risks of transfusions and practitioners about the indications for transfusion could prevent blood-borne virus transmission in Karachi

Non-Newtonian effects in the peristaltic flow of a Maxwell fluid

We analyzed the effect of viscoelasticity on the dynamics of fluids in porous media by studying the flow of a Maxwell fluid in a circular tube, in which the flow is induced by a wave traveling on the tube wall. The present study investigates novelties brought about into the classic peristaltic mechanism by inclusion of non-Newtonian effects that are important, for example, for hydrocarbons. This problem has numerous applications in various branches of science, including stimulation of fluid flow in porous media under the effect of elastic waves. We have found that in the extreme non-Newtonian regime there is a possibility of a fluid flow in the direction {\it opposite} to the propagation of the wave traveling on the tube wall.Comment: to Appear in Phys. Rev. E., 01 September 2001 issu

Pro-poor intervention strategies in irrigated agriculture in Asia: poverty in irrigated agriculture: issues and options: Bangladesh

Irrigated farming / Poverty / Irrigation management / Water resource management / Policy / Planning / Institutions / Organizations / Local government / Non-governmental organizations / Legislation / Water users / Participatory management / Public sector / Water allocation / Cost recovery / Households / Income / Expenditure / Irrigation canals / Bangladesh

Behind the counter: pharmacies and dispensing patterns of pharmacy attendants in Karachi.

BACKGROUND: There is little literature available on dispensing patterns and unsupervised sale of medicines from pharmacies in developing countries. OBJECTIVE: This study obtained background information on pharmacies assessed the level of training, knowledge and dispensing patterns of pharmacy attendants in Karachi. METHODOLOGY: This is a descriptive cross sectional study with convenient sampling. A structured questionnaire was used to interview pharmacy attendants. RESULTS: Of the 219 pharmacies surveyed, 62% reported more than 50 customers daily and 20% also sold items of general provision. Mean operating hours were 13. Only 24 (11%) had a visible license. On an average 3 attendants were employed per pharmacy. We interviewed one in each. Amongst the 219 interviewed, 77 (35%) were intermediate qualified and only 26 (12%) pharmacologically trained. Correct frequency of ORS administration was not known by 167 (76%) and 21% incorrectly suggested an anti-diarrhoeal preparation for viral diarrhoea in children. The knowledge of those with pharmacological training was significantly better. For respiratory tract infection in children approximately 60% did not know the correct dose of Paracetamol and Amoxicillin. Only 13 (6%) knew that Propanalol was contraindicated in hypertensive asthamatics. For Cotrimoxazole, metronidazole and lomotil only 40%, 21% and 15% respectively, were aware that these could not be dispensed without prescription. CONCLUSION: In the absence of trained pharmacists existing pharmacy attendants should be trained to improve drug-dispensing patterns

Ischaemic stroke and peripheral artery disease

Objective: To determine the frequency of atherosclerosis by ankle brachial index in patients with an ischaemic stroke and to assess the association of carotid artery stenosis and ankle brachial index in ischaemic stroke. Methods: This cross-sectional study was conducted at Abbasi Shaheed Hospital, Karachi, from July 2011 to May 2014, and comprised patients with ischaemic stroke. The patients were classified according to the Asian stroke criteria for classification of brain infarction. Primary outcome measures included carotid artery stenosis and ankle brachial index. The other independent variables were age, gender, body mass index and waist circumference. SPSS 20 was used for data analysis. Results: A total of 327 patients were enrolled. The overall mean age was 57.612.8 years. Besides, 168(51.3%) participants were males. Peripheral artery disease was found in 60(18.3%) patients. Mild carotid artery stenosis was found in 182(55.6%) patients, moderate in 140(42.8%), severe in 3(0.9%) and complete occlusion in 2(0.6%) patients. In patients having mild carotid artery stenosis, 32(17.5%) had peripheral artery disease, whereas in patients with moderate carotid artery stenosis, 25(17.8%) had peripheral artery disease. Conclusion: Abnormally low ankle brachial index suggesting subclinical peripheral artery disease was 18%. Keywords: Ischaemic stroke, Peripheral artery disease, Ankle brachial index, Carotid artery stenosis. (JPMA 67: 1138; 2017)sch_pod67pub4830pub

The genome and transcriptome of Trichormus sp NMC-1: insights into adaptation to extreme environments on the Qinghai-Tibet Plateau

The Qinghai-Tibet Plateau (QTP) has the highest biodiversity for an extreme environment worldwide, and provides an ideal natural laboratory to study adaptive evolution. In this study, we generated a draft genome sequence of cyanobacteria Trichormus sp. NMC-1 in the QTP and performed whole transcriptome sequencing under low temperature to investigate the genetic mechanism by which T. sp. NMC-1 adapted to the specific environment. Its genome sequence was 5.9 Mb with a G+C content of 39.2% and encompassed a total of 5362 CDS. A phylogenomic tree indicated that this strain belongs to the Trichormus and Anabaena cluster. Genome comparison between T. sp. NMC-1 and six relatives showed that functionally unknown genes occupied a much higher proportion (28.12%) of the T. sp. NMC-1 genome. In addition, functions of specific, significant positively selected, expanded orthogroups, and differentially expressed genes involved in signal transduction, cell wall/membrane biogenesis, secondary metabolite biosynthesis, and energy production and conversion were analyzed to elucidate specific adaptation traits. Further analyses showed that the CheY-like genes, extracellular polysaccharide and mycosporine-like amino acids might play major roles in adaptation to harsh environments. Our findings indicate that sophisticated genetic mechanisms are involved in cyanobacterial adaptation to the extreme environment of the QTP

The professional and personal impact of the coronavirus pandemic on US neurointerventional practices: a nationwide survey

Background Little is currently known about the effects of the coronavirus (COVID-19) pandemic on neurointerventional (NI) procedural volumes or its toll on physician wellness. Methods A 37-question online survey was designed and distributed to physician members of three NI physician organizations. Results A total of 151 individual survey responses were obtained. Reduced mechanical thrombectomy procedures compared with pre-pandemic were observed with 32% reporting a greater than 50% reduction in thrombectomy volumes. In concert with most (76%) reporting at least a 25% reduction in non-mechanical thrombectomy urgent NI procedures and a nearly unanimous (96%) cessation of non-urgent elective cases, 68% of physicians reported dramatic reductions (\u3e50%) in overall NI procedural volume compared with pre-pandemic. Increased door-to- puncture times were reported by 79%. COVID-19-positive infections occurred in 1% of physician respondents: an additional 8% quarantined for suspected infection. Sixty-six percent of respondents reported increased career stress, 56% increased personal life/family stress, and 35% increased career burnout. Stress was significantly increased in physicians with COVID-positive family members (P\u3c0.05). Conclusions This is the first study designed to understand the effects of the COVID-19 pandemic on NI physician practices, case volumes, compensation, personal/family stresses, and work-related burnout. Future studies examining these factors following the resumption of elective cases and relaxing of social distancing measures will be necessary to better understand these phenomena

Pharmacological Evaluation and Synthesis of New Sulfonamides Derivatives Based on 1,4-Benzodioxane

We report here the synthesis of a series of N-aryl-2,3-dihydrobenzo[1,4]dioxine-6-sulfonamide and its N-substituted derivatives with benzyl chloride and ethyl iodide. Initially, 2,3-dihydrobenzo[1,4]dioxine-6-sulfonyl chloride (1) was subjected to react with various aryl amines (2a-e) to afford parent compounds N-aryl-2,3-dihydrobenzo[1,4]dioxine-6-sulfonamide (3a-e). At second step, these parent compounds were reacted with benzyl chloride (4) and ethyl iodide (5) as to synthesize N-benzyl-N-aryl-2,3-dihydrobenzo[1,4]dioxine-6-sulfonamide (6a-e) and N-ethyl-N-aryl-2,3-dihydrobenzo[1,4]dioxine-6-sulfonamide (7a-e) in the presence of lithium hydride and N,Nꞌ-dimethylformamide respectively. FT-IR, Nuclear Magnetic Resonance (1H-NMR) and Mass Spectrometry (MS) techniques were used to investigate the structures of these synthesized compounds. A fingerprinted study was conducted against some enzymes like butyrylcholin-esterase (BChE), acetylcholinesterase (AChE) and lipoxygenase (LOX). This study revealed that most of them demonstrated a moderate activity against butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) however promisingly a good activity against lipoxygenase enzyme was observed. Finally, an antimicrobial and hemolytic activities of these sulfonamides were probed which confirmed that the parent sulfonamides 3b have the proficient antimicrobial activities, while the derivatives 6a, 7a, 7b and 7c explored a good activity against the selected panel of bacterial and fungal species. All the compounds were further computationally docked against (LOX), (BChE) and (AChE) enzymes and these interaction highlighted the importance of sulfonamides in the inhibition of the target enzymes