1,720 research outputs found
Static Parameters of Hadrons and Quantum Groups
We study the static properties of hadrons, assuming quantum group symmetry.
We calculate the magnetic moment, axial form factor and A-symmetry, using
and quantum groups. The results are fitted with
experimental data, giving an interval of . Some of the implications
for the deformation parameter are discussed.Comment: 18 pages in LaTeX, one figure is included in PS foram
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Exceptional Points of Degeneracy Induced by Linear Time-Periodic Variation
We present a general theory of exceptional points of degeneracy (EPD) in periodically time-variant systems. We show that even a single resonator with a time-periodic component is able to develop EPDs, contrary to parity-time- (PT) symmetric systems that require two coupled resonators. An EPD is a special point in a system parameter space at which two or more eigenmodes coalesce in both their eigenvalues and eigenvectors into a single degenerate eigenmode. We demonstrate the conditions for EPDs to exist when they are directly induced by time-periodic variation of a system without loss and gain elements. We also show that a single resonator system with zero time-average loss-gain exhibits EPDs with purely real resonance frequencies, yet the resonator energy grows algebraically in time since energy is injected into the system from the time-variation mechanism. Although the introduced concept and formalism are general for any time-periodic system, here, we focus on the occurrence of EPDs in a single LC resonator with time-periodic modulation. These findings have significant importance in various electromagnetic and photonic systems and pave the way for many applications, such as sensors, amplifiers, and modulators. We show a potential application of this time-varying EPD as a highly sensitive sensor
Detection of Drug Resistance Gene in Cutaneous Leishmaniasis by PCR in Some Endemic Areas of Iran
Background: Cutaneous leishmaniasis is still a health problem in many rural and urban regions of Iran and drug resistance has emerged as a major impediment in the treatment of leishmaniasis. This study aims to determine the drug resistance gene in cutaneous leishmaniasis by PCR in some endemic areas of Iran. Methods: Ninety seven samples were collected from ulcers of leishmaniasis patients from some endemic areas of Iran. The Giemsa stained samples were examined microscopically and cultured in NNN and RPMI 1640 mediums for parasite detection. After DNA extraction, PCR was done by a pair of specific primers. For detection of mutation in DNA, first PCR products were electrophoresed on CSGE gel. The suspected samples were compared by sequencing and RFLP results were demonstrated. Comparison of DNA derived from a wild type cell and mutant cell was undertaken by CSGE and sequencing methods. Results: Among 90 isolates (92.8) examined for detection of mutation in gene with CSGE and RFLP, 10 (11.1) revealed a disorder in sequencing selection for unresponsive to drug. Conclusion: Drug resistance in cutaneous leishmaniasis to sodium stiboglocanat is probably due to a mutation in a genome. A field study is needed to determine the distribution of drug resistance and other gene mutations involved in unresponsiveness to drugs in leishmaniasis endemic areas of Iran. © Iranian Red Crescent Medical Journal
Comparison of ferment sugars, produce hemolysis and measuring growth in methicillin-resistant and methicillin-sensitive Staphylococcus aureus isolates from inpatients and healthcare workers in Gorgan Hospitals, North of Iran
The mec A gene in Staphylococcus aureus leads to production of new penicillin-binding protein called PBP2a.This change may follow some changes in other phenotypes. The aim of this study was the comparison of Ferment Sugars, Produce Hemolysis and Measuring Growth in MRSA and MSSA isolates. 188 Staphylococcus aureus isolates separated from inpatients and healthcare workers (healthy carriers)were studied.Bacterialcultures in blood agar environment at 37°C during 24h and at 4°C during other 24h were applied for studying hemolysis. Sugar fermentation carried out in phenol red Broth medium, containing glucose, galactose, arabinose, fructose, xylose, ramnose, mannose, sucrose, trehalose, raffinose or maltose. For determining bacterial growth,bacterial concentration of 103was taken each hour during 12 cultured in MHAand colonies were counted after 24h.The mean amount of hemolysis diameter in MRSA isolates was rather more than that of MSSA isolates. The difference between MRSA and MSSA isolates were significant as to fermenting ramnose, trehalose, galactose and xylose. The mean rate of growth in MRSAwere significantly different from that of MSSAisolates (p<0.05).Resistance to methicillin in Staphylococcus aureus isolates accompanies the increase of ability to ferment sugars. This phenomenon may be one of reasons for increased pathogenicity of MRSA isolates; So results shows the logarithmic phase is longer in MRSA isolates, This may implicate that PBP2a production in methicillin-resistant isolates follows slowing down nutrients entrance into the bacterium that in turn may causes slow growth
Comparing the effects of alcoholic extract of ginseng with itraconazole against Candida albicans and Candida krusei
Background: Candidiasis is a prevalent disease which is caused by different species of Candida. Herbal drugs (e.g. ginseng) were traditionally administrated for the treatment of different diseases. This study was carried out to compare the effect of alcoholic extract of ginseng with Itraconazole against Candida albicans (C. albicans) and Candida krusei (C. krusei). Material and Methods: This cross-sectional study was crried out on 22 and 8 species of C.albicans and 8 C.krusei, respectively which were isolated from vagina, urine and sputum of the patients. Using the CLSI M27 and disk diffusion methods the susceptibility test was done by Itraconazole (10 µg) and ginseng extract (1, 2, 4, 8, 16, 32, 64 and 128 mg.ml-1). The standard species of C. albicans (PTCC 5027) and C. Krusei (PTCC 5295) were used for the quality control purposes. Results: The lowest and highest minimum inhibitory concentration (MIC) for C. albicans and C. Kruzei was 0.0625 and 0.5 μg.ml-1, respectively for Itraconazole using the microdilution method. However, the lowest MIC and minimum fungal concentration (MFC) for alcoholic extract was 64 mg.ml-1 .The highest inhibition zone for C. albicans was 14 and 14-32 mm for alcoholic extract and Foritraconazole, respectively. Using the two methods no significant difference was seen between the alcoholic extract of ginseng (64 and 128 mg.ml-1) and the drug. (P<0.05) Conclusion: Considering the MICs and disk diffusion results, the ginseng extract (64,128 mg.ml-1) shows considerable antifungal effects compared to Itraconazole
Study on ITS1 Gene of Iranian Trichomonas vaginalis by Molecular Methods
Background: Trichomoniasis is a worldwide protozoan parasitic disease and metronidazole is a choice drug for its treatment. Because of disease importance in public health and its controversial ideas about the prevalence of drug resistance, this study was carried out.Methods: Fifty-two suspected vaginal samples were collected from 2006 to 2007 in Gynecology Maryam Hospital, Tehran, Iran. All isolates were examined by microscopic, culture and PCR techniques. The PCR products were analyzed by RFLP and CSGE methods and two suspected samples were sequenced.Results: Trichomonas vaginalis was identified from all 52 samples. Of 52 isolates, 45 samples were successfully cultured and amplified by PCR except one. Seven were positive only by PCR. Finally, ITS1 fragment was successfully amplified in 51 of 52. CSGE analysis and PCR products digestion by MspI followed by sequencing showed nucleotide mutation at position 209 (C209T) of the ITS1 fragment in two (3.9%) of them.Conclusion: The results showed mutation in ITS1 fragment of T. vaginalis in two (3.9%) of Iranian isolates which may be related to metronidazole resistance
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Depression, anxiety, stress, and dysmenorrhea: a protocol for a systematic review
Background: Dysmenorrhea is one of the most common menstrual disorders and is influenced by various factors. Psychological disorders including anxiety, depression, and stress have been suggested as influencing dysmenorrhea, but previous findings are inconsistent. This study will investigate the relationship between depression/anxiety/stress and dysmenorrhea using a systematic review and meta-analysis.
Methods: Online databases including PsycINFO, Scopus, PubMed, Science Direct, ProQuest, ISI Web of Knowledge, and Embase will be searched. Appropriate keywords and MeSH terms will be used to retrieve the journal papers published from 1990 until the end of December 2019. To improve search coverage, the reference lists of all included studies will be reviewed to find eligible papers. Inclusion criteria include the following: descriptive, cohort, case-control, and cross-sectional studies; the relationship between depression/anxiety/stress and dysmenorrhea being an objective of the study; and published in peer-reviewed journals. The paper selection, data extraction, and quality assessment of selected studies will be performed independently by two researchers, and disagreements will be resolved through discussions. The Newcastle-Ottawa Quality Assessment Scale will be used to assess the quality of selected studies. A quantitative synthesis will be performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) via the STATA software, if retrieving enough number of studies with no severe methodological heterogeneities. Otherwise, qualitative synthesis will be used to report the findings.
Discussion: To the best of our knowledge, this will be the first systematic review on this topic. Performing an inclusive search in major databases over a wide timescale is one key strength of the proposed study and will maximize the coverage of the original research studies on this topic. Results of present study are expected to lead to deeper understanding the relationship between common mental health conditions and dysmenorrhea
Induced Nucleon Polarization and Meson-Exchange Currents in (e,e'p) Reactions
Nucleon recoil polarization observables in reactions are
investigated using a semi-relativistic distorted-wave model which includes one-
and two-body currents with relativistic corrections. Results for the induced
polarization asymmetry are shown for closed-shell nuclei and a comparison with
available experimental data for C is provided. A careful analysis of
meson exchange currents shows that they may affect significantly the induced
polarization for high missing momentum.Comment: 7 pages, 9 figures. Revised version with small changes, new curve in
Fig. 3. To be published in PR
Effect of hypoxia, normoxia and hyperoxia conditions on gill histopathology in two weight groups of beluga (Huso huso)
The influence of dissolved oxygen concentration on gill histopathology of great sturgeon (Huso huso) was evaluated in two weight classes (initial weight 280.9±49.2 g and 1217.9±138.1 g respectively). Oxygen treatments included hypoxia (2-3 mg/l), normoxia (5-6 mg/l) and hyperoxia (9-10 mg/l). The fish were acclimated to experimental tanks for one week then randomly distributed into 9 tanks in each of the initial weight classes (3 and 6 fish per tank in higher and lower initial weight classes respectively) for 8 weeks. In order to find the histopathological changes, gill samples were collected, dehydrated through ethanol series, embedded in paraffin , sectioned at 7 µm thickness using a Leitz microtome and stained with H & E. No mortality was observed over the 8 weeks of the experimental period. There were significant differences in weight and feed intake between treatments in the both weight classes (P<0.05). Fork length showed significant differences in lower initial weight class (P<0.05). The main histopathological changes were observed in gills including: Hyperplasia, loss of secondary lamellae, hemorrhage and congestion in primary and secondary lamellae, lamellar fusion, epithelial lifting in secondary lamellae, clubbing of secondary lamellae, telangiectases, increase in melanin pigments and numerous vacuoles in primary and secondary lamellae (in hyperoxia treatment). All these lesions may reduce gill functional surface of gaseous exchange, impairing respiratory function
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