700 research outputs found
Crossing statistics of laser light scattered through a nanofluid
In this paper, we investigate the crossing statistics of speckle patterns
formed in Fresnel diffraction region by a laser beam scattering through a
nanofluid. We extend statistics to assess dynamical properties
of nanofluid. According to joint probability density function of laser beam
fluctuation and its time derivative, theoretical framework for Gaussian and
non-Gaussian regimes are revisited. We count number of crossings not only at
{\it zero} level but also for all available thresholds to determine the average
speed of moving particles. Using probabilistic framework in determining
crossing statistics, {\it a priori} Gaussianity is not essentially considered,
therefore even in presence of deviation from Gaussian fluctuation, this
modified approach is capable to compute relevant quantities such as mean value
of speed more precisely. Generalized total crossing which represents the
weighted summation of crossings for all thresholds to quantify small deviation
from Gaussian statistics is introduced. This criterion can also manipulate the
contribution of noises and trends to infer reliable physical quantities. The
characteristic time scale for having successive crossings at a given threshold
is defined. In our experimental setup, we find that increasing sample
temperature leads to more consistency between Gaussian and perturbative
non-Gaussian predictions. The maximum number of crossing does not necessarily
occur at mean level indicating that we should take into account other levels in
addition to {\it zero} level to achieve more accurate assessments.Comment: 12 pages, 7 figures, 2 tables. Matched to accepted versio
Linear-nonlinear stiffness responses of carbon fiber-reinforced polymer composite materials and structures: a numerical study
The stiffness response or load-deformation/displacement behavior is the most important mechanical behavior that frequently being utilized for validation of the mathematical-physical models representing the mechanical behavior of solid objects in numerical method, compared to actual experimental data. This numerical study aims to investigate the linear-nonlinear stiffness behavior of carbon fiber-reinforced polymer (CFRP) composites at material and structural levels, and its dependency to the sets of individual/group elastic and damage model parameters. In this regard, a validated constitutive damage model, elastic-damage properties as reference data, and simulation process, that account for elastic, yielding, and damage evolution, are considered in the finite element model development process. The linear-nonlinear stiffness responses of four cases are examined, including a unidirectional CFRP composite laminate (material level) under tensile load, and also three multidirectional composite structures under flexural loads. The result indicated a direct dependency of the stiffness response at the material level to the elastic properties. However, the stiffness behavior of the composite structures depends both on the structural configuration, geometry, lay-ups as well as the mechanical properties of the CFRP composite. The value of maximum reaction force and displacement of the composite structures, as well as the nonlinear response of the structures are highly dependent not only to the mechanical properties, but also to the geometry and the configuration of the structures
Formation of Nanostructured Al-Mg-Si Alloys and Evaluation Its Properties
In this study, nanostructured Al-Mg-Si (Al6061) alloy was prepared from elemental powders by mechanical alloying and heat treatment. 98.4% aluminum, 1% magnesium, 0.6% silicon powders were mixed
and mechanically alloyed under argon atmosphere. The rotation speed of 500rpm and ball to powder ratio
of 10:1 was employed. The mechanical alloyed powder was isothermally heat treated at 400 degrees Celsius for 2 h under argon atmosphere.
The results showed that after 10h of milling, a solid solution of Al-Mg-Si with a grain size of ~ 40 nm
was produced. The as milled and annealed powder was characterized by scanning electron microscopy
(SEM) and X-ray diffraction (XRD). The microhardness values of alloy increase by increasing MA time.
Mg2Si particles precipitate from solid solution during subsequent annealing. The as milled powder
appeared to have good thermal stability against grain growth so that the grain size after annealing
remained constant (~ 40 nm).
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3486
Comparison of closure of subcutaneous tissue versus non-closure in relation to wound infection and disruption after cesarean section delivery in obese patients.
چکیده: زمینه و هدف: باز شدگی زخم یکی از عوارض مهم بعد از سزارین است و چاقی یکی از ریسک فاکتورهای عفونت زخم به همراه سایر عوارض می باشد. این مطالعه با هدف مقایسه اثر دوختن یا ندوختن بافت زیر جلد در ایجاد عفونت و باز شدگی زخم بعد از عمل سزارین در افراد چاق انجام شده است. روش بررسی: در یک مطالعه کارآزمایی بالینی در شهرستان یزد 100 نفر از زنان چاقی (که بافت زیر جلد آنها حداقل cm2 بود) و با روش سزارین زایمان می کردند به دو گروه 50 نفری تقسیم شدند، در گروه مورد بعد از دوختن فاشیای شکم بافت زیر جلد با نخ ویکریل 2/0 سوچور شد و گروه شاهد بعد از دوختن فاشیا، زیر جلد را باز گذاشته و جلد ترمیم شد. بیماران هر دو گروه از نظر ترشحات عفونت و باز شدگی زخم بررسی شدند. نتایج مطالعه با تست های آماری t-student و کای دو بررسی شد. یافته ها: هر دو گروه از نظر سن، تعداد زایمان، نوع بیهوشی و نوع انسزیون یکسان بودند. عفونت چرکی (کشت مثبت) در 2 نفر ازگروه مورد و 5 نفر از گروه شاهد مشاهده شد (05/0
Induction of cytochrome P4501A1 by beta-naphtho flavone and determination of enzyme properties in Huso huso
Cytochrome P4501 AI is a major isoenzyme in fish monooxygenase system which is induced by polycyclic aromatic hydrocarbons (PAHs) compounds. In this research, the inducing effect of p-naphtoflavone and its catalytic properties was studied in Huso huso liver. Fish were given ip injection of p-naphthoflavone at three different doses. The enzyme activity was measured with de-ethylation of ethoxyresorufin reaction (EROD) by flourometery method and relative amount of induced proteins were determined using polyacrylamid del electrophoresis (SDS-PAGE). The results showed that EROD activity in the microsomal fraction of the treated fish was 15-26 folds that of the control group. Optimum activity of this enzyme was observed at 20-25 degrees centivade. The maximum enzyme activity was seen in the precence of 180 micrograms of microsomai protein and 1.5311M of 7-ethoxyresorufin. SDS-PAGE of microsomal protein pattern in the treated fish revealed a protein with molecular mass 58+1 KDa translating to cytochrome P4501A. We conclude that the p-naphtoflovone in fish liver can induce cytochrome P4501A gene and increase its biosenthysis leading to raised enzyme activity in EROD reaction
Structural and Electrical Investigation of Cobalt-Doped NiOx/Perovskite Interface for Efficient Inverted Solar Cells
Inorganic hole-transporting materials (HTMs) for stable and cheap inverted
perovskite-based solar cells are highly desired. In this context, NiOx, with low synthesis temperature,
has been employed. However, the low conductivity and the large number of defects limit the boost
of the efficiency. An approach to improve the conductivity is metal doping. In this work, we have
synthesized cobalt-doped NiOx nanoparticles containing 0.75, 1, 1.25, 2.5, and 5 mol% cobalt (Co) ions
to be used for the inverted planar perovskite solar cells. The best efficiency of the devices utilizing the
low temperature-deposited Co-doped NiOx HTM obtained a champion photoconversion efficiency
of 16.42%, with 0.75 mol% of doping. Interestingly, we demonstrated that the improvement is not
from an increase of the conductivity of the NiOx film, but due to the improvement of the perovskite
layer morphology. We observe that the Co-doping raises the interfacial recombination of the device
but more importantly improves the perovskite morphology, enlarging grain size and reducing the
density of bulk defects and the bulk recombination. In the case of 0.75 mol% of doping, the beneficial
effects do not just compensate for the deleterious one but increase performance further. Therefore,
0.75 mol% Co doping results in a significant improvement in the performance of NiOx-based inverted
planar perovskite solar cells, and represents a good compromise to synthesize, and deposit, the
inorganic material at low temperature, without losing the performance, due to the strong impact
on the structural properties of the perovskite. This work highlights the importance of the interface
from two different points of view, electrical and structural, recognizing the role of a low doping Co
concentration, as a key to improve the inverted perovskite-based solar cells’ performance
Drug-related mutational patterns in hepatitis B virus (HBV) reverse transcriptase proteins from Iranian treatment-Naïve chronic HBV patients
Background: Immunomodulators and Nucleotide analogues have been used globally for the dealing of chronic hepatitis B virus (HBV) infection. However, the development of drug resistance is a major limitation to their long-term effectiveness. Objectives: The aim of this study was to characterize the hepatitis B virus reverse transcriptase (RT) protein variations among Iranian chronic HBV carriers who did not receive any antiviral treatments. Materials and Methods: Hepatitis B virus partial RT genes from 325 chronic in active carrier patients were amplified and directly sequenced. Nucleotide/amino acid substitutions were identified compared to the sequences obtained from the database. Results: All strains belonging to genotype D.365 amino-acid substitutions were found. Mutations related to lamivudine, adefovir, telbivudine, and entecavir occurred in (YMDD) 4% (n = 13), (SVQ) 17.23% (n = 56), (M204I/V + L180M) 2.45% (n = 8) and (M204I) 2.76% (n = 9) of patients, respectively. Conclusions: RT mutants do occur naturally and could be found in HBV carriers who have never received antiviral therapy. However, mutations related to drug resistance in Iranian treatment-naïve chronic HBV patients were found to be higher than other studies published formerly. Chronic HBV patients should be monitored closely prior the commencement of therapy to achieve the best regimen option. © 2013, KOWSAR Corp
Anticonvulsant and neuroprotective effects of Pimpinella anisum in rat brain
Background: Essential oil of Pimpinella anisum L. Apiaceae (anise oil) has been widely used in traditional Persian medicine to treat a variety of diseases, including some neurological disorders. This study was aimed to test the possible anti-seizure and anti-hypoxia effects of anise oil.
Methods: The effects of different concentrations of anise oil were tested on seizure attacks induced by pentylenetetrazol (PTZ) injection and neuronal hypoxia induced by oxygen withdrawal as well as on production of dark neurons and induction of long-term potentiation (LTP) in in vivo and in vitro experimental models of rat brain.
Results: Anise oil significantly prolonged the latency of seizure attacks and reduced the amplitude and duration of epileptiform burst discharges induced by injection of intraperitoneal PTZ. In addition, anise oil significantly inhibited production of dark neurons in different regions of the brain in epileptic rats. Anise oil also significantly enhanced the duration of the appearance of anoxic terminal negativity induced by oxygen withdrawal and inhibited induction of LTP in hippocampal slices.
Conclusions: Our data indicate the anticonvulsant and neuroprotective effects of anise oil, likely via inhibition of synaptic plasticity. Further evaluation of anise oil to use in the treatment of neurological disorders is suggested
Measuring the degree of development and educational deprivation of Sistan and Baluchistan Counties
Background and Objectives: Education sector and its indicators as one of the most important components of the social dimension of sustainable development, by playing its fundamental and crucial role in the process of comprehensive development, has a very important and key role and it is prerequisite for achieving the development of communities. Education has always been a concern of governments in achieving a fair distribution of facilities and expertise and has therefore been one of the most important public policies. Public education improves the productivity of low-income and poor people; because it improves their position in the labor market, and as a result, through education, income and welfare gaps can be reduced, and these gaps in turn affect the degree of development of the countries. Therefore, the issue of inequality is a major development challenge in many countries, especially for those countries whose sovereignty includes vast geographical areas. These inequalities make a serious threat to the balanced development of the regions and make it difficult to achieve the national unity. The present study aimed to investigate the development level of Sistan and Baluchistan counties in educational facilities and services according to student’s population. Methods: The research method of this study is descriptive - analytical. The statistical population of the research is the counties of the province in 2016. The statistical sample of the study is 19 counties of the province. The required data for this study was obtained from the province's 2015 statistical yearbook. In the present study, 23 effective indicators in the education sector were used to obtain a logical answer to the main research questions. In this way, in order to analyze the data, at first, the Shannon entropy technique was used to weigh the indicators and then, based on TOPSIS technique with the help of TOPSIS Solver and Excel software, the extent of development of counties in terms of their access to educational facilities were analyzed and determined. Findings: The results of the research show that according to the TOPSIS method, the county of Zahedan is the most developed county and Dalgan is the most deprived county in the province. Based on this index, and according to the educational facilities, the counties of Zahedan, Hamoon, Konarak, Zabol and Sarbaz are the most developed counties in the province; and Dalgan, Qasr-e Qand, Mehrestan and Fanoj are the most deprived counties, respectively. Conclusion: Research findings show that 84.21% of the province counties are at relatively deprived and deprived level of development and none of the counties of the province are at a developed or relatively developed level. The findings of this study indicate the inadequate distribution of educational facilities and services in Sistan and Baluchestan province. Unfair concentration and distribution of educational resources and facilities in different regions of the province will aggravate the underdevelopment of counties and their further backwardness. Therefore, considering the abundant deprivation of the counties of this province in the field of educational indicators, it is necessary for provincial and national officials to make more serious efforts at the national and provincial levels to eliminate these inequalities and under-development of educational development in this vast province. ===================================================================================== COPYRIGHTS ©2021 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers. ====================================================================================
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