883 research outputs found
Novel Technique of Fabrication of Porous Copper and Copper Oxide to Improve the Lithium Ion Battery Performance
Due to widespread and long-term application, Lithium-ion batteries are considered as promising power sources for portable devices, satellites, medical instruments, computers, electric vehicles and grid application. It started to occupy the market once Sony commercialized in 1991. Rechargeable lithium ion batteries drawing people attention due to their peculiar properties such as high energy density and low self-discharge compared to other alkali metals. However, these widespread and long-term applications still require better batteries in terms of performance, safety and cost, which can be achieved by better utilization of anode materials and/or an optimized design of battery configuration. There are several challenges in improving the battery performance, safety and to reduce the cost. The goal of this work was to design a high-performance battery with fabricating porous current collector and copper oxide. Current collector are essential features of batteries and being responsible for efficient charge transport to active electrode materials. In this study, a chemically treated high surface area, three-dimensional copper current collectors considerable improve the anodic performance of a batteries, by means of enhance in specific capacity and control over the fast decay. The electron transfers rapidly at the junction of the metal foam, the active material, and the electrolyte which increase the rate of redox reaction. On the other hand, the transfer of electron relatively slowly between foil current collector and the electrolyte surface of the active material. Impedance analysis also reveals that the charge transfer resistance is lower in porous copper current collector than the non-porous one. Unique properties of porous copper current collector improve the first discharge specific capacity of Li2 Ti5O12 (LTO) from 168.5 mAhg-1 to 235.8 mAhg-1 in comparison with the non-porous copper current collector. Moreover, fabrication of binder-free copper oxide on top of porous copper can open new window to the battery research
Agonist versus antagonist protocol in induction of ovulation and its outcome
Background: Gonadotropin-releasing hormone (GnRH) antagonist produces immediate suppression of gonadotrophins secretion without the initial stimulatory effect of premature luteinizing hormone (LH) .The aim of the study was to compare the agonist and the antagonist protocol in the induction of ovulation.Methods: The study is a comparative study conducted from 01 November 2011 to 31 August 2013. All patients of primary or secondary infertility underwent a baseline transvaginal sonography on day 2 or day 3rd of the menstrual cycle for follicle count and endometrial thickness. All patients received oral contraceptive pills from day 5 for 21 days of menstrual cycle and were assigned to two categories; the agonist and the antagonist group.Results: A total of 380 patients, 190 patients of agonist group 52 had a positive β hCG (human chorionic gonadotropin) report (27.3%) compared to the 60 patients of 190 antagonist group (31.5%). The P value was 0.44 which is statistically insignificant. Age group were similar and mean age of agonist group was27.96+3.21 where as in antagonist group 28.11+3.24. The number of oocyte retrieved was found to be better in the antagonist group compared to agonist group (mean±sd 10.71+6.41 versus 8.62±5.65, P value<0.001). The patients in the agonist group had a slightly more number of transfers performed (2.78±0.94), in comparison to the antagonist group (2.75±0.97). P-value was 0.789 which was statistically insignificant.Conclusions: The GnRH antagonist therefore seems to be a more patient friendly protocol for the first choice in ART cycle with lower incidence of side effects and similar pregnancy rate. It is also time saving and simple protocol with good clinical outcome
Clinical experience using Delta 4 phantom for pretreatment patient-specific quality assurance in modern radiotherapy
Purpose In advanced radiotherapy techniques such as intensity-modulated radiation therapy (IMRT), the quality assurance (QA) process is essential. The aim of the study was to assure the treatment planning dose delivered during delivery of complex treatment plans. The QA standard is to perform patient-specific comparisons between planned doses and doses measured in a phantom. Materials and method The Delta 4 phantom (Scandidos, Uppsala, Sweden) has been used in this study. This device consists of diode matrices in two orthogonal planes inserted in a cylindrical acrylic phantom. Each diode is sampled per beam pulse so that the dose distribution can be evaluated on segment-by-segment, beam-by-beam, or as a composite plan from a single set of measurements. Ninety-five simple and complex radiotherapy treatment plans for different pathologies, planned using a treatment planning system (TPS) were delivered to the QA device. The planned and measured dose distributions were then compared and analysed. The gamma index was determined for different pathologies. Results The evaluation was performed in terms of dose deviation, distance to agreement and gamma index passing rate. The measurements were in excellent agreement between with the calculated dose of the TPS and the QA device. Overall, good agreement was observed between measured and calculated doses in most cases with gamma values above 1 in >95% of measured points. Plan results for each test met the recommended dose goals. Conclusion The delivery of IMRT and volumetric-modulated arc therapy (VMAT) plans was verified to correspond well with calculated dose distributions for different pathologies. We found the Delta 4 device is accurate and reproducible. Although Delta4 appears to be a straightforward device for measuring dose and allows measure in real-time dosimetry QA, it is a complex device and careful quality control is required before its use
Prevalence of Helicobacter Pylori among Patients undergoing Gastrodudenoscopy in a Hospital in Western Nepal
Introduction: Helicobacter pylori (H. pylori) related chronic gastritis is a major health problem worldwide, specially in the developing countries. The prevalence of H. pylori infection has been reported to vary between and even within countries. There are limited data on this infection in Western Nepal. Our objective was to study the prevalence of H. pylori infection and its association with presenting complains and upper gastrointestinal diseases.
Methods: Medical records of patients undergoing gastrodudenoscopy and biopsy for various upper gastrointestinal symptoms from 1st of January 2015 to 30th of June 2017 were reviewed for presence of H. pylori infection, demographics, indications for gastrodudenoscopy, and histopathology findings. T-test, Chi-square test, and Fisher exact test were applied.
Results: Two hundred fifty six patients (135 male and 121 female) with a mean age of 47 (SD = 16.5) underwent gastroscopic biopsy and had an overall H. pylori prevalence of 24.6%. H. pylori infection was most commonly noted between 41 to 60 years of age. Gender did not seem to be significantly associated (p = 0.82) but gastrointestinal bleed was significantly associated with H. pylori infection (p = 0.006). The most common histopathological diagnosis was gastritis followed by gastrodudenitis; however, none of the diagnosis were found to be significantly associated with H. pylori infection.
Conclusion: The overall prevalence of H. pylori infection was 24.6% and was most common between 40 to 60 years of age. Heart burn was the most common symptom and gastrointestinal bleed was the only significantly associated symptom with H. pylori infection
Investigation of anomaly in the -specific 2HDM with Vector like leptons and the phenomenological implications
The anomalous magnetic moment of muons has been a long-standing problem in
SM. The current deviation of experimental value of the from the
standard model prediction is exactly . Two Higgs Doublet Models can
accommodate this discrepancy but such type of model naturally generate flavor
changing neutral current(FCNC). To prevent this it was postulated that 2HDM
without FCNC required that all fermions of a given charge couple to the same
Higgs boson but the rule breaks in Muon Specific Two Higgs Doublet Model where
all fermions except muon couple to one Higgs doublet and muon with the other
Higgs doublet. The Muon Specific Two Higgs Doublet model explain muon anomaly
with a fine tuning problem of very large value with other
parameters. We have found a simple solution of this fine tuning problem by
extending this model with a vector like lepton generation which could explain
the muon anomaly at low value with a heavy pseudo scalar Higgs
boson under the shadow of current experimental and theoretical constraints.
Moreover, with the help of the cut based analysis and multivariate analysis
methods, we have also attempted to shed some light on the potential
experimental signature of vector lepton decay to the heavy Higgs boson in the
LHC experiment. We have showed that a multivariate analysis can increase the
vector like leptons signal significance by up to an order of magnitude than
that of a cut based analysis.Comment: 24 pages and multiple figures, comments are welcom
Administration of Stabilized Flyash Stratum in Flexible Pavements
Expansive soils are major source of heave stimulated structural agony. Swelling of expansive soils cause grave problems and create damage to structures. Extensive work has been carried out on waste materials concerning the feasibility and environmental suitability. Flyash, a waste byproduct from coal burning in thermal power stations is bountiful in India causing health, environmental and dumping problems. Stabilization process with model test tracks over expansive subgrade in flexible pavements is one of the solutions. Cyclic plate load tests along with heave measurements are carried out on the tracks with chemicals like lime and cement introduced in flyash subbase laid on expansive subgrades. Test results show that maximum load carrying capacity is obtained for treated alternatives compared to untreated alternatives. Keywords: Expansive soil, Flyash, Lime, Cement,Flexible pavemen
Clinico-radiological Profile of Stroke in Western Nepal
Introduction: Stroke is a major public health burden worldwide and is responsible for a large proportion of disability. It ranks third in the causation of morbidity and mortality. This study was carried out to establish the pattern of various types of cerebrovascular accident (CVA) in western Nepal, to correlate the clinical data and radiological findings in cases of stroke, and to identify the common risk factors associated with stroke.
Methods: A total of 200 patients presented at the department of Radiodiagnosis from emergency or ward within six months of study period from 18th of September 2015 to 17th of March 2016 with clinical diagnosis of stroke. Brain CT scan was done within 14 days of onset.
Results: There were 200 patients with stroke (124 males and 76 females), aged 19 to 92 years in which infarction was more common than hemorrhage (57% Vs 41.5%) clinically. Hypertension was the commonest risk factor noted in 59% cases followed by Diabetes Mellitus in 39%. Middle cerebral artery (MCA) territory infarction was the most common site of infarction. Clinical and CT localization of hemorrhage and infarct was correct in 153 cases (75%) which was statistically significant.
Conclusion: Infarction is more common than hemorrhage as the type of stroke. Hypertension is the commonest risk factor followed by diabetes mellitus.  
Pattern of Acute Poisoning Attending a Tertiary Care Hospital of Western Nepal
Introduction: Poisoning with various substances is a major public health problem and a reason for significant morbidity and mortality throughout the globe. It is one of the most common presentation in an emergency department. This study was conducted to determine the sociodemographic, poisoning types, and mode of poisoning in cases attending a tertiary hospital of Western Nepal.
Methods: A retrospective observational study of two years was conducted from July 2014 to June 2016. Demography details, name of poisonous substance, and reasons for poisoning were reviewed and analyzed using descriptive statistics.
Results: A total of 65 cases of poisoning were recorded. The occurrence was more common in female (n=44, 67.7%) than in male (n=21, 32.3%) with a F:M ratio of 2.1:1. Poisoning was most common in the age group of 11-20 years (32.3%). Most of the cases were students (37%) followed by farmers (26%). The most commonly abused poisoning substance were organophosphorous compounds, zinc-phosphate, and kerosene in adults, adolescents, and children respectively. Oral route was the most common (99%) route of administration. Suicidal attempt, as a mode of poisoning, accounted for 70.8% of total poisoning cases.
Conclusion: Female and young people are at greater risk of acute poisoning. Insecticide was the most common agent and self administer poisoning was the most common mode of poisoning. The occurrence of poisoning and its morbidity and mortality can be reduced by developing and implementation of effective prevention strategies like restricting easy poison sales, establishing drug and poison information centers, and community awareness programs
Benefits and limitations of volumetric modulated arc therapy in treating bilateral breast cancer with regional lymph nodes
Purpose: The study was performed comparing dosimetric characteristics of
volumetric modulated arc therapy (VMAT) and field-in-field (FiF) techniques on a patient with synchronous bilateral breast carcinoma. Methods:
The patients with bilateral breast cancer treatment were included in this
study. A total dose of 40.05 Gy in 15 fractions was prescribed to the Planning
Target Volume (PTV) of the whole bilateral breast cancer with the supraclavicular and infraclavicular nodes, with a complementary boost of 10 Gy in 4
fractions to the surgical bed (PTVboost). For both radiotherapy techniques,
several VxGy parameters were analyzed for the PTVs, together with the Conformity index (CI), the Homogeneity index (HI) and the critical organs at
risk (OARs), lungs and heart. Results: The patient was treated by the VMAT
technique and the daily treatment time was less than 20 minutes with daily
CBCT imaging. In the VMAT plan, the PTV 95% dose covered 38.89 ± 0.81
Gy, compared to 37.26 ± 1.02 Gy in the FiF technique. The VMAT plan improved the dose homogeneity index and lower dose in lung towards high dose
region. Conclusion: The study demonstrates the viability of the VMAT technique in the treatment of bilateral breast cancer. The introduced single isocentric VMAT technique is fast to deliver and it increases the dose homogeneity of the target volume with some limitations. The treatment was well
tolerated, without interruption of the treatment courses caused by treatmentrelated toxicities
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