7,799 research outputs found
Properly Quantized History Dependent Parrondo Games, Markov Processes, and Multiplexing Circuits
In the context of quantum information theory, "quantization" of various
mathematical and computational constructions is said to occur upon the
replacement, at various points in the construction, of the classical
randomization notion of probability distribution with higher order
randomization notions from quantum mechanics such as quantum superposition with
measurement. For this to be done "properly", a faithful copy of the original
construction is required to exist within the new "quantum" one, just as is
required when a function is extended to a larger domain. Here procedures for
extending history dependent Parrondo games, Markov processes and multiplexing
circuits to their "quantum" versions are analyzed from a game theoretic
viewpoint, and from this viewpoint, proper quantizations developed
Formulation and Evaluation of Tramadol HCl Matrix Tablets Using Carbopol 974P and 934 as Rate-Controlling Agents
Purpose: To formulate and prepare controlled release (CR) matrix tablets of tramadol HCl using Carbopol 974P and 934 polymers as rate-controlling agents.Methods: The tablets were prepared by direct compression method using various drug to polymer (D:P) ratios. Co-excipients, including carboxymethylcellulose, starch and/or hydroxypropyl methylcellulosewere also used to modulate the formulations. Various physical tests and in vitro dissolution studies were carried out on the formulations. The dissolution data were subjected to various release modelsResults: As the concentration of the polymer (rate-controlling agent) increased, dissolution rate decreased, For the formulation containing Carbopol 974P at D:P ratio of 10:7, drug release decreased to 83 % compared with the release rate of 99 % for the formulation with D:P ratio of 10:3. Kinetic analysis indicates that drug release mechanism was anomalous non-Fickian diffusion.Conclusion: Both Carbopol 974P and 934 can be used as rate-controlling agents in the formulation of tramadol HCl CR tablets. Appropriate selection of drug/polymer ratio can be applied effectively to modulate the dissolution rate of the drug.Keywords: Tramadol, Carbopol, Carboxymethylcellulose (CMC), Hydroxypropyl methylcellulose, Controlled releas
Reducing machining distortion in AA 6061 alloy through re-heating technique
Solution-treated AA 6061 alloy contains residual stresses which cause unwanted deformation during the machining operation rendering the parts unacceptable for use. Usually for AA 6061 alloy, stress relieving is performed by re-heating the parts at 343°C for 1 h. This stress relieving is however accompanied by a considerable loss of material strength which subsequently reduces the functionality of the parts. This paper is based on an effort to evaluate the effectiveness of lower re-heating temperatures for stress relieving without significant loss of strength. Temperatures within the range of 200–343°C were used and treated samples were tested for both the strength and machining distortion. The experimental results indicate 60% reduction in machining distortions with 21% decrease in the strength
Cataract prevalence, cataract surgical coverage and barriers to uptake of cataract surgical services in Pakistan: the Pakistan National Blindness and Visual Impairment Survey.
AIM: To estimate the prevalence of visual impairment and blindness caused by cataract, the prevalence of aphakia/pseudophakia, cataract surgical coverage (CSC) and to identify barriers to the uptake of cataract services among adults aged >or=30 years in Pakistan. METHODS: Probability proportional-to-size procedures were used to select a nationally representative sample of adults. Each subject underwent interview, visual acuity measurement, autorefraction, biometry and ophthalmic examination. Those that saw <6/12 in either eye underwent a more intensive examination procedure including corrected visual acuity, slit lamp and dilated fundus examination. CSC was calculated for different levels of visual loss by person and by eye. Individuals with <6/60 in the better eye as a result of cataract were interviewed regarding barriers. RESULTS: 16 507 Adults were examined (95.5% response rate). The crude prevalence of blindness (presenting <3/60 in the better eye) caused by bilateral cataract was 1.75% (95% CI 1.55%, 1.96%). 1317 Participants (633 men; 684 women) had undergone cataract surgery in one or both eyes, giving a crude prevalence of 8.0% (95% CI 7.6%, 8.4%). The CSC (persons) at <3/60, <6/60 and <6/18 were 77.1%, 69.3% and 43.7%, respectively. The CSC (eyes) at <3/60, <6/60 and <6/18 were 61.4%, 52.2% and 40.7%, respectively. Cost of surgery (76.1%) was the main barrier to surgery. CONCLUSION: Approximately 570 000 adults are estimated to be blind (<3/60) as a result of cataract in Pakistan, and 3,560000 eyes have a visual acuity of <6/60 because of cataract. Overall, the national surgical coverage is good but underserved populations have been identified
Gut modulator effects of Conyza bonariensis explain its traditional use in constipation and diarrhea
BACKGROUND AND OBJECTIVES:
The current investigation was carried out to explore the pharmacological basis of the crude extract of Conyza bonariensis (Cb.Cr) for its use in constipation and diarrhea. MATERIALS AND METHODS:
The plant extract of Conyza bonariensis (C. bonariensis) was prepared, isolated guinea-pig ileum and rabbit jejunum preparations were used to evaluate its gut modulator effects. RESULTS:
The Cb.Cr (0.3-10 mg/mL) exhibited spasmogenic effect in isolated guinea-pig ileum preparation, which was about 19-84% of the acetylcholine maximum. Pretreatment of the tissues with atropine (0.1 µM) abolished the contractile effect, similar to acetylcholine. Among the fractions, only the butanol fraction exhibited atropine sensitive contractile effect. In isolated rabbit jejunum preparations, Cb.Cr produced appreciable atropine-sensitive spasmogenic effect at lower concentrations (0.03-0.3 mg/mL) followed by spasmolytic effect at next higher concentration (1.0 and 3.0 mg/mL). Cb.Cr caused an inhibition of the high K+ induced contraction in isolated rabbit jejunum preparation with EC50 value of 0.62 mg/mL. Similarly, verapamil, a standard calcium blocker, inhibited high K+ induced contraction in isolated rabbit jejunum preparations. Cb.Cr caused a right ward shift in the Ca++ concentration response curve, similar to verapamil. Among various fractions of C. bonariensis, only hexane and ethylacetate fractions showed spasmolytic effects. CONCLUSIONS:
The crude extract of C. bonariensis contains spasmogenic and spasmolytic constituents, which explains its medicinal use in constipation and diarrhe
Premedication in Surgical Day Care Patients
The purpose of this audit was to find out the efficiencyof our system in providing premedication to surgical daycare patients. This audit was conducted in the Surgical DayCare (SDC) Unit of a University Hospital. All patientsanaesthetised in the SDC unit on day care basis were includedin this audit. Nursing notes and preoperative orders of allpatients to be anaesthetised were checked to see whetherpremedication was given or not and was the timing accordingto the orders written. The result showed that out of 205patients scheduled, twenty (9.7%) patients did not receivepremedication. Only 37.2% of our patients were receivingpremedication according to the orders. The majority of theerrors noted in our audit were system errors related to cancellation,rescheduling and admitting the outpatient in theinpatient ward
Landslide susceptibility assessment using Frequency Ratio, a case study of northern Pakistan
The northern Pakistan is attributed with rough terrain, active seismicity, monsoon rains, and therefore hosts to variety of geohazards. Among the geohazards, landslides are the most frequent hazard with devastating impacts on economy and society. However, for most of the northern Pakistan, landslide susceptibility maps are not available which can be used for landslide hazard mitigation. This study aims to develop a remote sensing based landslide inventory, analysing their spatial distribution and develop the landslide susceptibility map. The area, selected for this study is comprised of Haramosh valley, Bagrote valley and some parts of Nagar valley, in the Central Karakoram National Park (CKNP) in Gilgit-Baltistan, northern Pakistan. The SPOT-5 satellite image was used to develop a landslide inventory
which was subsequently verified in the field. The landslide causative factors of topographic attributes (slope and aspect), geology, landcover, distances from fault, road and streams were used to evaluate their influence on the spatial distribution of landslides. The study revealed that the distance to road, slope gradient
has the significant influence on the spatial distribution of the landslides, followed by the geology. The derived results were used in the Frequency ratio technique to develop a landslide susceptibility map. The developed landslide susceptibility map can be utilized for landslide mitigation in the study area
MULTI-HAZARD RISK ASSESSMENT OF QURUMBAR VALLEY, GHIZER, GILGIT BALTISTAN, PAKISTAN
Being located in a seismically active zone, these mountain valleys are exposed to different hydro-meteorological hazards like rockfall, debris flow, landslide, ice avalanches, and glacial lake outburst flood (GLOFs). The present study is to investigate different multi-hazards and their prevailing risk in the particular area of Qurumbar valley Ishkoman. In the mid-nineteen and twenty centuries at least six devastating glacial lake outburst floods (GLOFs) has been recorded, initially, only the Qurumbar glacier was considered as the main cause of this outburst flood, later field investigation and interview from local inhabitant revealed that nine more tributary glacier are existing in the area. The recent outburst of flood in the Badswat area of Qurumbar Ishkoman is also considerable, submerging 12 houses and a stretch of roads. Apart from it, the physical vulnerability of the area is increasing, as new areas are being used for housing with the increase in population. The study area is exposed to several other natural hazards like rock fall, debris flows, ice avalanches, and bank erosion. The present study is based on quantitative and qualitative approaches in assistance with GIS/RS an emergent application. The following methodologies were adapted to gather the primary and secondary data for GIS/RS processing. The primary data comprises GIS data and procurement and development and field data. The field data contain ground-truthing /validation. The community-based Hazard Vulnerability Risk Assessment (HVRA) was also carried out to know about human perception. Secondary data has been collected from different literature. Both the data were put into GIS for the processing which gives us our final developmental tools in the form of maps. The hazard and risk map of the Qurumbar Ishkoman depict that flash floods, debris flow, bank erosion, and GLOFs account for major hazards in Qurumbar valley. It is concluded based on our outcomes i.e., hazard and risk maps that earthquake is the main hazard of the area while flash floods, GLOFs, debris flow, bank erosion and the bank collapsed are the main hazards of the area. It is very important to systematically integrate map information into the planning and management process which contributes to a safer environment
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