382 research outputs found
Incorporating Betweenness Centrality in Compressive Sensing for Congestion Detection
This paper presents a new Compressive Sensing (CS) scheme for detecting
network congested links. We focus on decreasing the required number of
measurements to detect all congested links in the context of network
tomography. We have expanded the LASSO objective function by adding a new term
corresponding to the prior knowledge based on the relationship between the
congested links and the corresponding link Betweenness Centrality (BC). The
accuracy of the proposed model is verified by simulations on two real datasets.
The results demonstrate that our model outperformed the state-of-the-art CS
based method with significant improvements in terms of F-Score
A simple powerful bivariate test for two sample location problems in experimental and observational studies
<p>Abstract</p> <p>Background</p> <p>In many areas of medical research, a bivariate analysis is desirable because it simultaneously tests two response variables that are of equal interest and importance in two populations. Several parametric and nonparametric bivariate procedures are available for the location problem but each of them requires a series of stringent assumptions such as specific distribution, affine-invariance or elliptical symmetry.</p> <p>The aim of this study is to propose a powerful test statistic that requires none of the aforementioned assumptions. We have reduced the bivariate problem to the univariate problem of sum or subtraction of measurements. A simple bivariate test for the difference in location between two populations is proposed.</p> <p>Method</p> <p>In this study the proposed test is compared with Hotelling's <it>T</it><sup>2 </sup>test, two sample Rank test, Cramer test for multivariate two sample problem and Mathur's test using Monte Carlo simulation techniques. The power study shows that the proposed test performs better than any of its competitors for most of the populations considered and is equivalent to the Rank test in specific distributions.</p> <p>Conclusions</p> <p>Using simulation studies, we show that the proposed test will perform much better under different conditions of underlying population distribution such as normality or non-normality, skewed or symmetric, medium tailed or heavy tailed. The test is therefore recommended for practical applications because it is more powerful than any of the alternatives compared in this paper for almost all the shifts in location and in any direction.</p
Factors Affecting Minor Psychiatric Disorder in Southern Iranian Nurses: A Latent Class Regression Analysis
Background: Mental health is one of the most important dimensions of life and its quality. Minor Psychiatric Disorder as a type of mental health problem is prevalent among health workers. Nursing is considered to be one of the most stressful occupations.
Objectives: This study aimed to evaluate the prevalence of minor psychiatric disorder and its associated factors among nurses in southern Iran.
Patients and Methods: A cross-sectional study was carried out on 771 nurses working in 20 cities of Bushehr and Fars provinces in southern Iran. Participants were recruited through multi-stage sampling during 2014. The General Health Questionnaire (GHQ-12) was used for screening of minor psychiatric disorder in nurses. Latent Class Regression was used to analyze the data.
Results: The prevalence of minor psychiatric disorder among nurses was estimated to be 27.5%. Gender and sleep disorders were significant factors in determining the level of minor psychiatric disorder (P Values of 0.04 and < 0.001, respectively). Female nurses were 20% more likely than males to be classified into the minor psychiatric disorder group.
Conclusions: The results of this study provide information about the prevalence of minor psychiatric disorder among nurses, and factors, which affect the prevalence of such disorders. These findings can be used in strategic planning processes to improve nurses’ mental health
Brittle or Quasi-Brittle Fracture of Engineering Materials: Recent Developments and New Challenges
1 Department of Management and Engineering, University of Padova, Stradella San Nicola 3, 36100 Vicenza, Italy 2 Departamento de Ciencia de Materiales, Universidad Politecnica de Madrid, E. T. S. de Ingenieros de Caminos Canales y Puertos C/ Profesor Aranguren s/n, 28040 Madrid, Spain 3 Fatigue and Fracture Research Laboratory, Center of Excellence in Experimental Solid Mechanics and Dynamics, School of Mechanical Engineering, Iran University of Science and Technology, Narmak, Tehran 16846, Iran 4Department of Mechanical Engineering & Aeronautics, Institute of Strength Physics and Material Science, Siberian Branch of Russian Academy of Sciences, Tomsk 634021, Russia 5 Laboratory of Technology & Strength of Materials (LTSM), Department of Mechanical Engineering & Aeronautics, University of Patras, 26500 Patras, Greec
Review of the Influence of non-singular higher order terms on the stress field of thin welded lap joints and small inclined cracks in plates
In stress analysis of cracked plates, alongside the stress intensity factor which quantifies the singular stress component perpendicular to the crack plane, the role played in crack growth by the constant term parallel to the crack plane, called the T-stress, has been widely investigated by many researchers. There are, however, cases of practical interest where the influence on the stress field of the higher order terms in the series expansion for the crack tip stress field, is not negligible. The main aim of the present investigation is to present and apply a set of equations able to describe more accurately the stress components for those cases where the mode I and mode II stress intensity factors used in combination with the T-stress are unable to characterise with sufficient precision the complete stress field ahead the crack tip. The starting point is represented by the Williams’ solution (Williams, 1957) where stresses as expressed in terms of a power series. An example is investigated of a thin-thickness welded lap joint characterized by various joint width to thickness ratios, in the range of d/t ranging from 0.5 to 5. The present paper indicates that the local stresses as well as the strain energy averaged over a control volume which embraces the slip tip, can be evaluated with satisfactory precision only by taking into account a further four terms besides KI, KII and T-stress
Green Synthesized Silver Nanoparticles as Potent Antifungal Agent against Aspergillus terreus Thom
Medicinal plants are composed of a rich pool of biomolecules and have been increasingly recognized for their antimicrobial properties; however, increasing concerns have been put on the bioavailability features. Thus, this study is aimed at exploring the synthesis and characterization of silver nanoparticles synthesized by Chenopodium album L. leaf extract and assessing the antifungal activity against Aspergillus terreus Thom. Plant extract was prepared in methanol to synthetize silver nanoparticles, which were then characterized by Scanning Electron Microscopy (SEM), UV-Visible spectroscopy, and particle size analysis. UV-Visible analysis indicated maximum absorption at 378 nm, and an average particle size was observed as 25.6 nm. Oval to hexagonal shape was observed by SEM. Antifungal activity of silver nanoparticles (1, 1.5, 2, 2.5, 3, and 3.5%) was addressed against A. terreus biomass. At 3.5%, silver nanoparticles revealed to be highly effective, leading to 92% retardation in fungus growth. In next phase, various organic fractions, viz., chloroform, n-butanol, n-hexane, and ethyl acetate, were obtained from plant methanol extract, and the corresponding silver nanoparticles were prepared. These fractions were also assessed for antifungal activity, and n-hexane fraction led to 64% inhibition in A. terreus biomass. Following gas chromatography-mass spectrometry (GC-MS), 18 compounds were identified, namely, 1,3-cyclopentadiene-5-(1 methylethylidene and o-xylene), ethyl benzene, octadecane, nonane, decane, 2-methylheptane, n-hexadecane, 2-methylheptane, and eicosane, along with carbonyl compounds (4,4-dimethyl-3-hexanone) and phenols, like stearic acid, propionic acid hydrazide, and 2,4-di-T-butylphenol. These findings proved that C. album silver nanoparticles are highly effective against A. terreus.N.C.-M. acknowledges the Portuguese Foundation for Science and Technology under the Horizon 2020 Program (PTDC/PSI-GER/28076/2017)
Analgesic effects of intravenous ketamine during spinal anesthesia in pregnant women undergone Caesarean section; a randomized clinical trial
Suitable analgesia after cesarean section helps mothers to be more comfortable and increases their mobility and ability to take better care of their infants. Objectives: Pain relief properties of ketamine prescription were assessed in women with elective cesarean section who underwent spinal anesthesia with low dose intravenous ketamine and midazolam and intravenous midazolam alone. Patients and Methods: Sixty pregnant women scheduled for spinal anesthesia for cesarean section were randomized into two study groups. Ketamine (30 mg) + midazolam (1 mg = 2CC) or 1mg midazolam (2CC) alone, was given immediately after spinal anesthesia. Pain scores at first, second and third hours after CS operation, analgesic requirement and drug adverse effects were recorded in all patients. Results: Ketamine group had significant pain relief properties in compare with control group in first hours after cesarean section (0.78 ± 1.09 vs. 1.72 ± 1.22, VAS score, P = 0.00). Total dose of meperidine consumption in women of ketamine group was significantly lower than women of control group (54.17 ± 12.86 vs. 74.44 ± 33.82 mg, P = 0.02). There were no significant drug side effects in participated patients. Conclusions: Intravenous low-dose ketamine combined with midazolam for sedation during spinal anesthesia for elective Caesarean section provides more effective and long lasting pain relief than control group. © 2013 Iranian Society of Regional Anesthesia and Pain Medicine
Evaluation of antifungal activities of the essential oil and various extracts of Nigella sativa and its main component, thymoquinone against pathogenic dermatophyte strains
Objective. — Plant extracts and plant-derived compounds are valuable sources as folk medicine
for the treatment and prevention of a wide range of diseases including infectious diseases. In the
present study, the antifungal activities of the essential oil and various extracts Nigella sativa and
its active principle, thymoquinone against Trichophyton mentagrophytes, Microsporum canis and
Microsporum gypseum as pathogenic dermatophyte strains have been evaluated. In addition, the
cytotoxic effects of N. sativa against murine macrophage cells were determined.
Materials and methods. — In this study, the antifungal activity was studied by disk diffusion
method and assessment of minimum inhibitory concentration (MIC) of extracts using broth macrodilution method. In addition, the cytotoxic activity of N. sativa was evaluated by
colorimetric assay (MTT). The components of the N. sativa essential oil were also identified
by gas chromatography/mass spectroscopy (GC/MS) analysis.
Results. — The results showed that the essential oil and various extracts of N. sativa particularly
thymoquinone have potent antifungal effects on T. mentagrophytes, M. canis and M. gypseum as
pathogenic dermatophyte strains. In the assessment of the cytotoxicity activity, it could be
observed that N. sativa had no significant cytotoxicity in the murine macrophages at low
concentrations. While, thymoquinone in comparison with essential oil and various extracts of
N. sativa showed higher cytotoxicity on murine macrophage cells. In the GC/MS analysis,
thymoquinone (42.4%), p-cymene (14.1%), carvacrol (10.3%) and longifolene (6.1%) were found
to be the major components of N. sativa essential oil.
Conclusion. — The findings of this study suggest a first step in the search of new antidermatophytic
drugs and aid the use of N. sativa seeds in the traditional medicine for dermatophytic
infections
Antibacterial activity of some Lamiaceae species against Staphylococcus aureus in yoghurt-based drink (Doogh)
Doogh is a dairy drinkable fermented product, whose shelf-life and quality is mostly affected by bacteria such as Staphylococcus spp. This study investigated the antibacterial activity of essential oils (EOs) from Thymus vulgaris L., Mentha piperita L. and Ziziphora tenuior L., alone or in combination, against Staphylococcus aureus in industrial doogh. A three-level and three-variable face centered central composite design experiment was used. Results showed that EOs significantly inhibited S. aureus growth after 1 and 7 days of storage. According to the model, the maximum inhibition was obtained in the presence of 0.2% of EO, independently of the type, and no synergistic or additive effects were observed. Slightly lower S. aureus survivals were observed at the maximum concentration of Z. tenuior EO. In spite of the antimicrobial activity of these EOs, further research is needed to assess their performance in food matrix and, in particular, in dairy product
Medicinal plants used in the treatment of human immunodeficiency virus
Since the beginning of the epidemic, human immunodeficiency virus (HIV) has infected around 70 million people worldwide, most of whom reside is sub-Saharan Africa. There have been very promising developments in the treatment of HIV with anti-retroviral drug cocktails. However, drug resistance to anti-HIV drugs is emerging, and many people infected with HIV have adverse reactions or do not have ready access to currently available HIV chemotherapies. Thus, there is a need to discover new anti-HIV agents to supplement our current arsenal of anti-HIV drugs and to provide therapeutic options for populations with limited resources or access to currently efficacious chemotherapies. Plant-derived natural products continue to serve as a reservoir for the discovery of new medicines, including anti-HIV agents. This review presents a survey of plants that have shown anti-HIV activity, both in vitro and in vivo
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