378 research outputs found
Knowledge, Attitude and Practice of Iranian Women Towards Breast Cancer Screening Methods
Female breast cancer is the second leading cause of death due to cancer and the second leading cause of cancer deaths in women after lung cancer. This study aimed to investigate the knowledge, attitude and practice of women about breast cancer\u27s screening methods in order to offer more appropriate training programs if necessary. A cross-sectional study was carried out with a population comprised of women who had referred to public health centers in Sanandaj in 2008. The results of this study do provide some understanding on the topic and suggest that although the majority of Iranian women seem to be quite knowledgeable about breast cancer and screening methods. They need more education on breast cancer, SBE and other methods of early detection. We recommend the establishment of an institutional framework and policy guidelines that will enhance adequate and urgent information dissemination about breast cancer and screening methods to all women in Iran. Since women\u27s beliefs and behaviors may impact young women, designing training courses for this group seems to be essential
Central Obesity and BMI Associated with Different Phenotypes of Polycystic Ovary Syndrome in Adolescent
Adipose tissue distribution is effective in metabolic complications resulting from obesity. Fat accumulation in the body, particularly increase in visceral fat, is a major risk factor of diabetes and cardiovascular diseases. The present study aimed to determine the prevalence of obesity and android obesity based on various phenotypes of Polycystic Ovarian Syndrome (PCOS) in 14-18 year old high-school girl students in Shiraz in 2009. This descriptive study was conducted on 14-18 year old high-school girl students in Shiraz in 2009. Considering the confidence coefficient of 95% and loss rate of 20%, a 3190subject sample size was determined for the study. The participants were selected through purposive sampling. After obtaining written informed consents, demographic information questionnaire was completed and the participants were examined regarding hirsutism, acne, alopecia, and menstrual disorders. Besides, the criteria proposed by Adams et al. were employed to diagnose PCOS in sonography. Android obesity and Body Mass Index (BMI) were evaluated, as well. The results of independent t-test showed no significant difference among various phenotypes of PCOS regarding mean android obesity and BMI (P>0.05). The results of the present study revealed no significant relationship between girl adolescents\u27 obesity and various phenotypes of PCOS. However, adolescents should be informed about the long-term hyperandrogenic outcomes which are accompanied by insulin secretion and endanger their health after the age of 40 years
The Cosmology of Composite Inelastic Dark Matter
Composite dark matter is a natural setting for implementing inelastic dark
matter - the O(100 keV) mass splitting arises from spin-spin interactions of
constituent fermions. In models where the constituents are charged under an
axial U(1) gauge symmetry that also couples to the Standard Model quarks, dark
matter scatters inelastically off Standard Model nuclei and can explain the
DAMA/LIBRA annual modulation signal. This article describes the early Universe
cosmology of a minimal implementation of a composite inelastic dark matter
model where the dark matter is a meson composed of a light and a heavy quark.
The synthesis of the constituent quarks into dark mesons and baryons results in
several qualitatively different configurations of the resulting dark matter
hadrons depending on the relative mass scales in the system.Comment: 31 pages, 4 figures; references added, typos correcte
Anomalous Dimensions and Non-Gaussianity
We analyze the signatures of inflationary models that are coupled to strongly
interacting field theories, a basic class of multifield models also motivated
by their role in providing dynamically small scales. Near the squeezed limit of
the bispectrum, we find a simple scaling behavior determined by operator
dimensions, which are constrained by the appropriate unitarity bounds.
Specifically, we analyze two simple and calculable classes of examples:
conformal field theories (CFTs), and large-N CFTs deformed by relevant
time-dependent double-trace operators. Together these two classes of examples
exhibit a wide range of scalings and shapes of the bispectrum, including nearly
equilateral, orthogonal and local non-Gaussianity in different regimes. Along
the way, we compare and contrast the shape and amplitude with previous results
on weakly coupled fields coupled to inflation. This signature provides a
precision test for strongly coupled sectors coupled to inflation via irrelevant
operators suppressed by a high mass scale up to 1000 times the inflationary
Hubble scale.Comment: 40 pages, 10 figure
Fano resonances in plasmonic core-shell particles and the Purcell effect
Despite a long history, light scattering by particles with size comparable
with the light wavelength still unveils surprising optical phenomena, and many
of them are related to the Fano effect. Originally described in the context of
atomic physics, the Fano resonance in light scattering arises from the
interference between a narrow subradiant mode and a spectrally broad radiation
line. Here, we present an overview of Fano resonances in coated spherical
scatterers within the framework of the Lorenz-Mie theory. We briefly introduce
the concept of conventional and unconventional Fano resonances in light
scattering. These resonances are associated with the interference between
electromagnetic modes excited in the particle with different or the same
multipole moment, respectively. In addition, we investigate the modification of
the spontaneous-emission rate of an optical emitter at the presence of a
plasmonic nanoshell. This modification of decay rate due to electromagnetic
environment is referred to as the Purcell effect. We analytically show that the
Purcell factor related to a dipole emitter oriented orthogonal or tangential to
the spherical surface can exhibit Fano or Lorentzian line shapes in the near
field, respectively.Comment: 28 pages, 10 figures; invited book chapter to appear in "Fano
Resonances in Optics and Microwaves: Physics and Application", Springer
Series in Optical Sciences (2018), edited by E. O. Kamenetskii, A. Sadreev,
and A. Miroshnichenk
Steel fiber reinforced concrete : a review
Concrete is one of the world most widely used construction material. However, since the early 1800’s, it has been known that concrete is weak in tension. Weak tensile strength combined with brittle behavior result in sudden tensile failure without warning. This is obviously not desirable for any construction material. Thus, concrete requires some form of tensile reinforcement to compensate its brittle behavior and improve its tensile strength and strain capacity to be used in structural applications. Historically, steel has been used as the material of choice for tensile reinforcement in concrete. Unlike conventional reinforcing bars, which are specifically designed and placed in the tensile zone of the concrete member, fibers are thin, short and distributed randomly throughout the concrete member. Fibers are commercially available and manufactured from steel, plastic, glass and other natural materials. Steel fibers can be defined as discrete, short length of steel having ratio of its length to diameter (i.e. aspect ratio) in the range of 20 to 100 with any of the several cross-section, and that are sufficiently small to be easily and randomly dispersed in fresh concrete mix using conventional mixing procedure. The random distribution results in a loss of efficiency as compared to conventional rebars, but the closely spaced fibers improve toughness and tensile properties of concrete and help to control cracking. In many situations it is prudent to combine fiber reinforcement with conventional steel reinforcement to improve performance. Fibre Reinforced Concrete (FRC) is defined as a composite material essentially consisting of conventional concrete or mortar reinforced by the random dispersal of short, discontinious, and discrete fine fibres of specific geometry. Since Biblical times, approximately 3500 years ago, brittle building materials, e.g. clay sun baked bricks, were reinforced with horse-hair, straw and other vegetable fibres. Although reinforcing brittle materials with fibers is an old concept, modern day use of fibers in concrete is only started in the early 1960s. Realizing the improved properties of the fiber reinforced concrete products, further research and development on fiber reinforced concrete (FRC) has been initiated since the last three decades. This paper presents an overview of the mechanical properties of Steel Fiber Reinforced Concrete (SFRC), its advantages, and its applications
Investigation of Chemical Properties of Green Tea Ethanolic Extract and Its Inhibitory and Lethal Effects on Aspergillus niger, Botrytis cinerea and Rhizopus stolonifer (Causing Rot in Strawberry and Grapes)
Introduction
Strawberry and grapes are generally infected with pathogenic fungi (e.g., Aspergillus niger, Botrytis cinerea, Rhizopus stolonifera, etc.). Synthetic fungicides are commonly used as the first line of defense against post-harvest pathogens on packaging lines. However, disposal of toxic waste is a costly process and the hazardous waste causes serious environmental problems. In addition, fungal pathogens have shown a worrying trend of resistance to these fungicides, thus shortening the shelf life of products. Compounds that can be equally effective in controlling pathogens, but preventing or minimizing the waste problems will be inevitable. The large volume of internationally processed agricultural products, as well as the increasing demand for organically produced fruits, emphasizes the need to replace synthetic fungicides with safer and biodegradable alternatives. Natural plant-derived products effectively meet this criterion and have great potential to influence modern agricultural research. Catechins and other polyphenols in green tea show strong antioxidant activity. Also, the antimicrobial activity of green tea extract against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans has been reported. Therefore, the present study was performed to prepare the ethanolic extract of green tea and to determine the content of total phenol, total flavonoids, antioxidant activity, and its antifungal effect against Aspergillus niger, Botrytis cinerea, and Rhizopus stolonifer (causing rot in strawberry and grapes).
Materials and Methods
Fresh green tea leaves were dried at room temperature and then powdered. Then, ethanol (70%) was added to the powdered leaves (solvent to powder ratio of 10:1 v/w) and the mixture was refluxed for 120 min. The resulting mixture was filtered through a filter paper and then concentrated under vacuum and finally dried in an oven.
Total phenol content (by Folin-Ciocalteu reagent at 756 nm), total flavonoid content (spectrophotometrically at 510 nm), antioxidant activity (by DPPH and ABTS radical scavenging methods), and antifungal effect (by disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum fungicidal concentration) of the extract were evaluated.
Results and Discussion
The extract contained 175.60 mg GAE /g total phenol and 47.53 mg QE/g total flavonoids and its antioxidant activity using DPPH and ABTS free radical assays was 78.89% and 86.57%, respectively. The results of antifungal activity showed that the diameter of the growth inhibition zone increased significantly with increasing the concentration of the extract, and Botrytis cinerea and Rhizopus stolonifer were the most sensitive and resistant fungal strains to the extract, respectively. The minimum fungicidal concentrations for the strains of Botrytis cinerea and Rhizopus stolonifer were 64 and 512 mg/ml, respectively.
Conclusion
The results of the present study showed that the ethanolic extract of green tea could be considered as potential source of natural antioxidant and antifungal agents. The presence of phenolic and flavonoid compounds may be responsible for the antifungal and antioxidant effects of the extract. However, due to the fact that this study was performed with the crude extract of green tea, it is difficult to identify compounds responsible for antifungal and antioxidant activity. On this point, only the separation of the components of the extract allows the detection of antifungal and antioxidant compounds. This study provides a basis for further researches, in particular the use of these antioxidants and antifungal compounds. Green tea extract is especially suitable for products with high sensitivity to lipid oxidation and infection with molds
Flexural behavior of Steel-Fiber-Added-RC (SFARC) beams with C30 and C50 classes of concrete
Although conventional reinforced concrete (RC) is the most globally used building material; however, its detrimental structural characteristics such as brittle failure mechanism in tension need to be improved. Discrete and short steel fibers (SFs) can be added into the concrete mix to improve its brittleness. The effects of the addition of optimum percentage of SFs on flexural behavior of RC beams have been investigated in this paper. In this study, the optimum percentage of hooked-end SFs with the dimensions of 0.75mm in diameter and 50mm in length are added in RC beams with two different classes of concrete (i.e. two different compressive strengths of 30MPa (C30) and 50MPa (C50)). In order to determine the optimum percentage of SFs added to the concrete mix, 5 prisms and 30 cubes with 5 different percentages of SFs (i.e. 0%v/v, 0.5%v/v, 1%v/v, 1.5%v/v, and 2%v/v) from both C30 and C50 classes of concrete have been tested. Based on the results of the flexural strength and compressive strength tests, it is found that the optimum value is 1% of SFs by volume (i.e. 78.5 kg/m3). To investigate the flexural behavior of steel fiber added RC (SFARC) beams compared to conventional RC beams with no SFs, two RC beams with the dimensions of 170 mm in height, 120mm in width, and 2400mm in length, with SF percentages of 0 and 1%v/v and both having exactly the same steel reinforcement were tested under flexure using a four-point loading test setup for both C30 and C50 classes of concrete. The experimental results show that the SFARC beams with 1.0% by volume of SFs have higher first cracking strength, ultimate flexural strength, stiffness, and ductility compared to those conventional RC beams with no SFs. Furthermore, the addition of SFs has more effects on RC beams with higher compressive strength (50MPa) compared to lower concrete grade (30MPa)
Evaluation of Antioxidant and Antimicrobial Properties of Nanoemulsion of Citrus paradisi Essential Oil Against Pathogenic Microorganisms: In Vitro Study
Introduction
Oxidation reactions and microorganisms’ activity are considered as the most important factors affecting the quality of food products. Recently, in the light of the inefficiency of some chemical preservatives against microorganisms and the presence of toxic residues in food products, the use of natural antimicrobials and antioxidants has been increased. Natural antimicrobial compounds have the potential to control microbial contamination and reduce the use of antibiotics. Plant essential oils are natural compounds with the potential to be used as active ingredients in the food, pharmaceutical, and cosmetic industries. Various studies have shown that essential oils have antifungal, antibacterial, antiviral, and antioxidant activity. The essential oils are considered as superb preservatives with various biological functions. Essential oils are generally recognized as safe product (GRAS) which can be used as an alternative to synthetic additives.
Grapefruit (Citrus paradisi) peel and fruit contain active ingredients such as acids, flavonoids, vitamin C, and potassium, and its essential oil is composed of terpenic hydrocarbons, such as citral, limonene, citronelal, and geraniol. Although plant essential oils have antimicrobial and antioxidant properties, one of the main problems of these natural compounds is their high volatility and instability. In this context, nanoemulsion formulations are frequently used to increase the stability and efficiency of these biologically active compounds. This study is therefore aimed to nanoemulsifying the grapefruit essential oil and evaluate its antioxidant and antimicrobial properties.
Materials and Methods
β-carotene, linoleic acid, ABTS (2,2’-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt), and DPPH (2,2-diphenly-1-picrylhydrazyl) were purchased from Sigma-Aldrich Co. (USA). Mueller Hinton Broth (MHB) and Mueller Hinton Agar (MHA) were supplied from Merck Co. (Darmstadt, Germany). Grapefruit peel was dried at ambient temperature and then powdered. The obtained powder was then transferred to a Clevenger device containing 750 ml of distilled water to perform the distillation extraction (3 h). The resulting grapefruit essential oil was stored at 4 °C until use. Grapefruit essential oil was prepared using the hydrodistillation method, and then nanoemulsified. The antioxidant activity of the nanoemulsified essential oil was investigated by DPPH and ABTS radical scavenging activity and beta-carotene/linoleic bleaching test. The nanoemulsified essential oil or methanolic (control) was mixed with DPPH solution and the mixture was then stored at ambient temperature for 30 min, in a dark place. The control sample was prepared by methanol. The absorbance of the samples was measured at 517 nm. To determine the ABTS-RS activity, the nanoemulsified essential oil was briefly charged with methanolic ABTS radical cation solution and the resulting mixture was left at room temperature for 30 min. Afterward, the absorbance was read at 734 nm. A spectrophotometric method was applied to monitor β-carotene/linoleate solution bleaching in the presence of the nanoemulsified essential oil. To do this, the absorbance of the solution was recorded at 490 nm after 120 min against the control sample at time zero and after 120 min. Antibacterial effect of the grapefruit essential oil nanoemulsion was also evaluated against Escherichia coli ATCC 25922, Salmonella typhi ATCC 6539, Pseudomonas aeruginosa ATCC 27853, Listeria innocua ATCC 33090, Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 14579, Bacillus subtilis ATCC 23857, Streptococcus pyogenes ATCC 19615, and Staphylococcus epidermidis ATCC 12228, based on disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration.
Results and Discussions
The results showed that the nanoemulsion of grapefruit essential oil had a remarkable antioxidant effect of 42.27 mg/ml, 33.27 mg/ml and 54.54%, respectively, based on DPPH, ABTS, and beta-carotene-linoleic acid bleaching tests. According to disk diffusion agar and well diffusion agar results, the lowest inhibition zone was related to E. coli and the highest inhibition zone was observed in L. innocua. The minimum inhibitory concentration for L. innocua and S. aureus (the most sensitive bacteria) was 25 mg/ml, and E. coli, S. typhi, and P. aeruginosa had the highest inhibitory concentration. Also, the lowest bactericidal concentration was related to L. innocua and S. aureus bacteria and the highest concentration was observed for E. coli, S. typhi and P. aeruginosa. The nanoemulsified essential oil generally exhibited greater antibacterial activity against Gram-positive species. This could be mainly due to the difference in the cell wall composition of Gram-positive bacteria in comparison to Gram-negative; Gram-positive bacteria have a thicker mucopeptide layer in their cell wall, while Gram-negative bacteria have only a thin layer of mucopeptide and the wall structure is mainly composed of lipoprotein and lipopolysaccharide, thereby leading to a higher resistant to antibacterial agents According to the results, grapefruit essential oil nanoemulsion can be used as a natural antioxidant and antimicrobial agent to control oxidation reactions and the growth of spoilage and pathogenic microorganisms
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