199 research outputs found
Vacuum Polarization and Casimir Energy of a Dirac Field Induced by a Scalar Potential in One Spatial Dimension
We investigate the vacuum polarization and the Casimir energy of a Dirac
field coupled to a scalar potential in one spatial dimension. Both of these
effects have a common cause which is the distortion of the spectrum due to the
coupling with the background field. Choosing the potential to be a symmetrical
square-well, the problem becomes exactly solvable and we can find the whole
spectrum of the system, analytically. We show that the total number of states
and the total density remain unchanged as compared with the free case, as one
expects. Furthermore, since the positive- and negative-energy eigenstates of
the fermion are fermion-number conjugates of each other and there is no
zero-energy bound state, the total density and the total number of negative and
positive states remain unchanged, separately. Therefore, the vacuum
polarization in this model is zero for any choice of the parameters of the
potential. It is important to note that although the vacuum polarization is
zero due to the symmetries of the model, the Casimir energy of the system is
not zero in general. In the graph of the Casimir energy as a function of the
depth of the well there is a maximum approximately when the bound energy levels
change direction and move back towards their continuum of origin. The Casimir
energy for a fixed value of the depth is a linear function of the width and is
always positive. Moreover, the Casimir energy density (the energy density of
all the negative-energy states) and the energy density of all the
positive-energy states are exactly the mirror images of each other. Finally,
computing the total energy of a valence fermion present in the lowest fermionic
bound state, taking into account the Casimir energy, we find that the lowest
bound state is almost always unstable for the scalar potential.Comment: 16 pages, 7 figure
Evaluation Of Antihyperglycemic Effects, Nutritional/Antinutritional Values And Phytochemical Contents Of Ocimum Tenuiflorum Linn
The leaves of Ocimum tenuiflorum L. (lamiaceae) (locally known as ruku) has been used to make nasi ulam in Malaysia. Therefore, the present work is aimed to explore the nutritional, antinutritional, and it`s anti diabetic effect on ruku tree. The result of the first phase showed that ruku leaves displayed higher values of the nutritional level (proximate, amino acid profile, fatty acid profile, vitamin and phytochemical content) compared to the stem. In addition, the result of antinutrients level in the ruku leaves and stem displayed within the safe level
Distribution and Prevalence Potato virus Y Isolates Obtained from Potatoes Grown in the Iran by RT-PCR
To survey the distribution and prevalence of potato virus Y (PVY) strains in north western Iran, 381 symptomatic infected samples of the main potatoes grown in the said region were collected from the fields between (Hall et al., 1998) 2007 and 2008. The collected samples were first tested for PVY infection via a double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) technique. Of the total number of collected samples, 79 (20.73%) tested positive for PVY infection. The highest level of PVY infection was observed in the district of Gilak-Abad in Sarab County, whereas the lowest infection was observed in the district of Oughan in the suburbs of Sarab city. The RT-PCR detection of PVY strains by using specific primers resulted in the amplification of DNA fragments specific to the PVY strains NTN, C, O, and N at 725, 1553, 352, and 616 bp, respectively. The highest strain diversity of PVY was detected in the district of Shirehjin in Sarab city and the lowest in the district of Ghaleh Jugh in Bostan-Abad city. Both single and multiple infection types of the PVY stains were observed in the region. Of the 79 PVY-infected samples, 77.21% were infected with strain O, 62.02% with strain C, 39.24% with strain N, and 8.86% with strain NTN. The highest level of multiple infections was observed in the combinations of the strains C+O (27.84%) and the triple strains O+N+C (15.18%). This paper is the first to report the detection of the PVY strain NTN in Iran. Keywords: RT-PCR, Molecular diagnosis, Potato, ELISA, Potato Virus Y (PVY
Thermodynamic study of PCB-153 passing into single walled carbon nanotube (8,8)
Polychlorinated biphenyl (PCBs) are high resistant pollutants which cause adverse health effects in recent years. The accumulation of these toxic compounds in the food chain lead to oxidative stress in various ecosystems. Detection, absorption, and elimination of them are an environmental priority. Passing of PCB-153 through the armchair single walled carbon nanotube (SWNT) (8,8) were investigated by MNDO in semi-empirical quantum method. Calculated electrical and thermodynamic properties show a sudden change in the middle of the tube which may act as a trap for the studied pollutant. The results indicated the nanotube has considerable ability to interact with PCB-153 and cause its degradation. According to calculated thermodynamic parameters through the molecular modeling, it is expected that single wall carbon nanotube is a candidate in remediation of PCBs as well as in gas sensor devices for detection of them. The median tube is a place for trapping pollutants
Pattern and Visual Prognostic Factors of Behcet’s Uveitis in Northwest Iran
Purpose: To investigate the pattern of ocular involvement in Behcet’s disease (BD) with predictors of patients’ final state of vision.
Methods: This historical cohort encompassed the clinical records of 200 patients diagnosed according to the International Criteria for BD (ICBD), over a period of 17 years between 2004 and 2021.
Results: The prevalence of Behcet’s uveitis (BU) was more common in females and patients in the fourth decade of life. Ninety-five patients (47.5%) had evidence of ocular involvement in the initial ophthalmologic evaluation, and 171 patients (85.5%) manifested evidence of BU during the follow-up visits of which bilateral non-granulomatous panuveitis was the most common anatomical pattern of involvement (32.9%) followed by posterior (27.6%), anterior (26.5%), and intermediate (13.8%) uveitis. The prevalent accompanying signs were oral aphthous (67%), skin lesions (29%), and genital ulcers (19.5%). Cystoid macular edema (CME) was the most frequent ocular complication (62%), followed by cataract (57.5%) and epiretinal membranes (ERM) (36.5%). Univariate analysis showed the following determinants: male gender, younger age at onset, panuveitis, posterior uveitis, retinal vasculitis, and longer duration of uveitis as poorer visual prognostic factors of the disease. Multivariate analysis demonstrated a higher chance of poor visual prognosis of BD in patients with panuveitis, posterior uveitis, retinal vasculitis, and longer duration of uveitis.
Conclusion: This cohort study demonstrated an overview on epidemiological patterns of BU along with the visual prognostic factors in Iranian patients
Comparison of rumination between men and women with obsessive- compulsive disorder and social anxiety disorder: a cross-sectional study
Introduction: Ruminations are one of the influencing factors in the development and continuation of obsessive-compulsive disorder and social phobias. Therefore, this study aimed to compare the rumination between man and women with obsessive-compulsive disorder and social anxiety.
Materials & Methods: The research design was cross-sectional. The research participants included 30 patients with social anxiety disorder and 30 patients with obsessive-compulsive disorder who were aged between 15 and 50 years from Zanjan city in 2017. Samples were selected on the basis of psychiatrist diagnosis and structured diagnostic interviews (SCID-I) and (SCID-II), and the inclusion and exclusion criteria. The rumination response style questionnaire (RRS) was used to measure the variables.
Results: The results of MANOVA showed that women with OCD have more rumination and distraction than men with this disorder (p≤0.05). However, there was no significant difference between two groups regarding the component of contemplation. There was no significant difference between men and women in social anxiety disorder in terms of rumination and its related components.
Conclusion: According to research findings, rumination plays an important role in obsessive-compulsive disorder and social anxiety, which are experienced by both groups. Therefore, the role of ruminations in women with obsessive-compulsive disorder is more intense.
 
Optical coherence tomography angiography in intermediate uveitis-related cystoid macular edema
Background: Cystoid macular edema (CME) is the leading cause of permanent visual impairment in patients with uveitis, particularly in patients with intermediate uveitis (IU). This study was aimed at comparing the changes in the macular microvasculature in patients with IU with uveitic non-responsive CME and without macular edema.
Methods: In this case-control study, 55 eyes of patients with IU were assessed for macular microvascular structures, including vascular density, foveal avascular zone (FAZ) measurement, and vascular morphological changes, using spectral-domain optical coherence tomography angiography (OCT-A) with the AngioVue OCT-A system. We divided patients into the following two groups: the case group, including 30 eyes with IU-related non-responsive CME, and the control group, including 25 eyes with IU without macular edema.
Results: Participants in the case and control groups had comparable age (P = 0.753) and sex (P = 0.124) distributions. Superficial capillary plexus vessel density in the case group was significantly decreased in the whole image (P = 0.027) and the parafoveal area (P = 0.001) compared to the control group. However, there were no statistically significant differences between the two groups in terms of foveal superficial vessel density, deep capillary plexus vessel density, FAZ area, FAZ perimeter, FAZ acircularity index, or foveal vessel density in a 300-µm-wide annulus around the FAZ (all P > 0.05). Vascular morphological changes, such as the capillary tuft, telangiectatic vessels, or micro-aneurism, were not different in the overview images of the OCT-A printout between the two groups.
Conclusions: The mean superficial capillary plexus vessel density was lower in eyes with IU-related nonresponsive CME than in those without macular edema. We observed more cystoid spaces in SCP than in DCP. Microcystic changes in the inner retina and ischemia may be the underlying cause in eyes with nonresponsive CME. Future prospective longitudinal studies with healthy, matched controls are warranted to confirm our findings
Cardiovascular Complications of Acute Amphetamine Abuse : Cross-sectional study
Objectives: This study aimed to evaluate cardiovascular complications among patients who abuse amphetamines. Methods: This cross-sectional study took place between April 2014 and April 2015 among 3,870 patients referred to the Toxicology Emergency Department of Baharlou Hospital, Tehran University of Medical Sciences, Tehran, Iran. Those with clinical signs of drug abuse and positive urine screening tests were included in the study, while cases of chronic abuse were excluded. Cardiac complications were evaluated via electrocardiography (ECG) and transthoracic echocardiography. Results: A total of 230 patients (5.9%) had a history of acute amphetamine abuse and positive urine tests. Of these, 32 patients (13.9%) were <20 years old and 196 (85.2%) were male. In total, 119 (51.7%) used amphetamine and methamphetamine compounds while 111 (48.3%) used amphetamines with morphine or benzodiazepines. The most common ECG finding was sinus tachycardia (43.0%), followed by sinus tachycardia plus a prolonged QT interval (34.3%). Mean creatine kinase-MB and troponin I levels were 35.9 ± 4.3 U/mL and 0.6 ± 0.2 ng/mL, respectively. A total of 60 patients (26.1%) were admitted to the Intensive Care Unit. The majority (83.3%) of these patients had normal echocardiography results. The mean aortic root diameter (ARD) was 27.2 ± 2.8 mm. Abnormalities related to the ARD were found in 10 patients (16.7%), three of whom subsequently died. Conclusion: According to these findings, cardiac complications were common among Iranian patients who abuse amphetamines, although the majority of patients had normal echocardiography and ECG findings
Administration of Nicotine Exacerbates the Quinine-induced Structural and Functional Alterations of Testicular Tissue in Adult Rats:An Experimental Study
Purpose: In this study the role of nicotine (NCT) administration on the intensity of rat testicular tissue alterations induced by quinine (QU) was evaluated. Materials and Methods: Forty adult Wistar rats were divided into four groups. Control (CON), NCT administrated (4 mg/kg) (NCT), QU treated (25 mg/kg for 7 days) (QU), and nicotine with quinine received (NCT+QU). After 28 days, serum testosterone and malondialdehyde (MDA) levels were measured. Testes and epididymides samples were prepared for determining tissue MDA levels, histomorphometry, microscopic indices of spermatogenesis, immunohistochemistry of p53 and sperm analysis. Results: Testosterone levels were decreased significantly (P =.0004) in treated groups compared to CON group. Serum MDA levels were increased significantly (P =.0004) in NCT and QU groups compared to CON group. Tissue MDA levels were increased significantly (P =.0012) in NCT+QU group in comparison to CON group. These parameters were changed significantly in NCT+QU group compared to QU group. Seminiferous tubules diameter decreased significantly (P Conclusion: The administration of nicotine could be involved in the exacerbation of testicular tissue alterations related to quinine therapy
The effectiveness of psychiatric therapy against Malaysian cancer patients with depressive disorders: a systematic review
The aim of this study is to compare depression in terms of treatment between psychotherapy and medical approach or to combine these approaches among cancer patients in Malaysia with respect to the
cancer categories. It also studies the major prevalence of depressive disorder in the group together
with the specialized clinical connection to the health outcomes. The annual incidence of cancer cases
in Malaysia is 30,000 at late stage of the disease. We found 17 eligible researches out of 142 articles
which most were under designed of cross-sectional or prospective study, and contained 2,523 cancer
patients. This study was conducted on systematic electronic review using the databases such as Pub-Med, Scopus, ScienceDirect, Google Scholar, Wiley Online Library were carried out from the period
of time between 2006 and 2015. For data collection purposes, the study goes through the Malaysian
articles in English language, in which some of the considered factors were general management principles, cancer level among the depressed patients, the selection of the psychological therapies and the
use of antidepressant medication. However, the evidences are still not enough to present an effective
diagnostic method for the depressive disorders in cancer patients, and to find a successful antidepressant drug and/or an appropriate psychotherapy in this group of patients. Hence, many different approaches could be presented for psychotherapy. In conclusion, we found increased hazard rates for
the cancer death among psychiatric patients compared to the control group without a registered mental illness
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