91 research outputs found

    Explicitly solvable cases of one-dimensional quantum chaos

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    We identify a set of quantum graphs with unique and precisely defined spectral properties called {\it regular quantum graphs}. Although chaotic in their classical limit with positive topological entropy, regular quantum graphs are explicitly solvable. The proof is constructive: we present exact periodic orbit expansions for individual energy levels, thus obtaining an analytical solution for the spectrum of regular quantum graphs that is complete, explicit and exact

    Effect of Cyperus rotundus on ischemia-induced brain damage and memory dysfunction in rats

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    Objective(s): Global cerebral ischemia-reperfusion injury causes loss of pyramidal cells in CA1 region of hippocampus. In this study, we investigated the possible neuroprotective effects of the ethanol extract of Cyperus rotundus (EECR) on a model of global transient ischemia in rat, by evaluating the pathophysiology of the hippocampal tissue and spatial memory. Materials and Methods: Treatment group (EECR, 100 mg/kg/day) was gavaged from 4 days before, to 3 days after ischemia. Morris water maze test was performed 1 week after ischemia for 4 days. Brain tissue was prepared for Nissl staining. Results: Our data showed no statistical difference between the treatment and ischemia groups in water maze task. So, treatment of ischemia with EECR cannot improve spatial learning and memory. On the contrary EECR ameliorated the CA1 pyramidal cell loss due to transient global ischemia/ reperfusion injury. Conclusion: These results suggest that EECR cannot reduce the ischemia-induced, cognitive impairments seen after transient, global cerebral ischemia but can prevent pyramidal cell loss in CA1 region of hippocampus. © 2015, Mashhad University of Medical Sciences. All rights reserved

    Spectra of regular quantum graphs

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    We consider a class of simple quasi one-dimensional classically non-integrable systems which capture the essence of the periodic orbit structure of general hyperbolic nonintegrable dynamical systems. Their behavior is simple enough to allow a detailed investigation of both classical and quantum regimes. Despite their classical chaoticity, these systems exhibit a ``nonintegrable analog'' of the Einstein-Brillouin-Keller quantization formula which provides their spectra explicitly, state by state, by means of convergent periodic orbit expansions.Comment: 32 pages, 10 figure

    Weyl formulas for annular ray-splitting billiards

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    We consider the distribution of eigenvalues for the wave equation in annular (electromagnetic or acoustic) ray-splitting billiards. These systems are interesting in that the derivation of the associated smoothed spectral counting function can be considered as a canonical problem. This is achieved by extending a formalism developed by Berry and Howls for ordinary (without ray-splitting) billiards. Our results are confirmed by numerical computations and permit us to infer a set of rules useful in order to obtain Weyl formulas for more general ray-splitting billiards

    One-dimensional quantum chaos: Explicitly solvable cases

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    We present quantum graphs with remarkably regular spectral characteristics. We call them {\it regular quantum graphs}. Although regular quantum graphs are strongly chaotic in the classical limit, their quantum spectra are explicitly solvable in terms of periodic orbits. We present analytical solutions for the spectrum of regular quantum graphs in the form of explicit and exact periodic orbit expansions for each individual energy level.Comment: 9 pages and 4 figure

    Anti-proliferative and apoptotic effects of aqueous extract of ziziphus jujube in human thyroid carcinoma cell lines (C643)

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    Background: Ziziphus jujuba, which is known as �Annab� or �Onnab� in Iran, is an effective compound against some cancer cell lines. The present study aimed to investigate the anti-mutagenic and anticancer effects of the aqueous extract of Z. jujuba on C643 human thyroid carcinoma cells. Methods: C643 cells were cultured in (Roswell Park memorial institute) RPMI 1640 medium (Sigma) supplemented with 10 fetal bovine serum (FBS), penicillin-streptomycin, and L-glutamine. After incubating the cultures at 37ºC with 5 CO2, MTT assay was used to determine the inhibitory effect of Z. jujuba on cell proliferation. Cell cycle progression was monitored by sub-G1 apoptosis assay using flow cytometry. Finally, anti-mutagenicity properties of the extract were evaluated using a standard reverse mutation assay (Ames test), which was performed with a histidine auxotroph strain of Salmonella typhimurium (TA100) and exposure to a carcinogenic substance (sodium azide). Results: The aqueous extract of Z. jujuba inhibited the growth of C643 cells in a concentration range of 0.5-2 mg/mL and exhibited cytotoxic effects on C643 cells in a concentration-dependent manner (IC50: 1.671 mg/mL). The mechanism of action was the induction of apoptosis in the cells. The results of Ames test indicated a significant difference in the anti-mutagenic effects of Z. jujuba aqueous extract and controls (distilled water and sodium azide) (1.671 mg/mL) (P < 0.01). In addition, the herbal extract prevented reverted mutations and the hindrance percent was 87.97. Conclusions: According to the results, the aqueous extract of Z. jujuba fruit exerted anti-proliferative and apoptotic effects on C643 thyroid carcinoma cell lines and may be potentially useful as an anticancer agent. © 2018, Author(s)

    Attitude and practice of diabetic patients towards complementary/alternative medicine and related factors, Sari, 2014-2015

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    Background and purpose: The purpose of this study was to evaluate the use of complementary/alternative medicine (CAM) and related factors in diabetic patients attending diabetes clinics in Sari and their attitudes and satisfaction. Materials and methods: In this cross-sectional study, the use of CAM methods, attitude and satisfaction of 270 diabetic patients, were assessed by a questionnaire. The t-test, chi-square test and logistic regression were used to analyze the related factors. Results: Among the participants 99 (36.6) had used at least one of the CAM methods in the year before the study. The most commonly used CAM were medicinal plants (n= 85 patients), cupping (n= 14), acupuncture (n= 11), bloodletting (n= 5), and massage (n= 1). The most common herbs were nettle, fenugreek, barberry, cinnamon, and green tea. More than 51 of patients expressed their satisfaction with the effects of these methods and over 67 were willing to use them again. There was a positive attitude towards CAM methods in 47 patients (17.4). A significant correlation was observed between the use of these methods and marriage (P= 0.02), duration of disease (P=0.01) and duration of treatment (P=0.02). Conclusion: In our study, the use of non-conventional methods in diabetic patients was found to be common which was related to duration of diabetes and its therapy. More studies are needed to evaluate the effects, side effects and interactions of these methods with conventional methods in treatment of diabetes. © 2016, Mazandaran University of Medical Sciences. All rights reserved

    Combination of Nigella sativa and honey in eradication of gastric helicobacter pylori infection

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    Background: Gastric Helicobacter pylori is extremely common worldwide. Objectives: The aim of this study was to assess the effectiveness of combination of Nigella sativa and honey (Dosin) in eradication of gastric H. pylori infection. Patients and Methods: Nineteen patients who had positive result for H. pylori infection by urea breath test (UBT) without a past history of peptic ulcer, gastric cancer or gastrointestinal bleeding, were suggested to receive one teaspoon of the mixture of Dosin (6 g/day of N. sativa as ground seeds and 12 g/day of honey) three times a day after meals for two weeks. The second UBT was used to detect the presence of H. pylori four weeks after completion of the test. In addition, symptoms of dyspepsia were scored before and after the study and analyzed with Wilcoxon signed-rank test Results: Fourteen patients completed the study. Negative UBT was observed in 57.1 (8/14) of participants after intervention. The median and interquartile range (IQR) of total dyspepsia symptoms was significantly reduced from 5.5 (5 -12) to 1 (0 -4) (P = 0.005). All the patients tolerated Dosin except for one who was excluded due to mild diarrhea. No serious adverse events were reported. Conclusions: Dosin was concluded to be an anti H. pylori and an anti-dyspeptic agent. Further studies are recommended to investigate the effect of Dosin plus antibiotics (concurrently or following another) on gastric H. pylori infection. � 2016, Iranian Red Crescent Medical Journal

    Exact trace formulae for a class of one-dimensional ray-splitting systems

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    Based on quantum graph theory we establish that the ray-splitting trace formula proposed by Couchman {\it et al.} (Phys. Rev. A {\bf 46}, 6193 (1992)) is exact for a class of one-dimensional ray-splitting systems. Important applications in combinatorics are suggested.Comment: 14 pages, 3 figure

    The effects of myrtle (myrtus communis) and clindamycin topical solution in the treatment of mild to moderate acne vulgaris: A comparative split-face study

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    Objectives: Although Acne vulgaris is a chronic skin disease, which its standard treatment causes therapeutic limitations and some common adverse effects, medicinal plants can be effective in treatment with low adverse effects as combination therapy. Myrtle (Myrtus Communis) has some beneficial properties, which has been administered topically and orally for some skin diseases in Persian medicine. This study aimed to compare the efficacy and safety of Myrtle formula and 1 clindamycin topical solution. Methods: This was a split-face clinical trial that was done on 55 patients with mild to moderate acne vulgaris for 16 weeks. The patients received topical Myrtle solution to the right side of the face (group 1) and clindamycin solution to the left side (group 2) twice daily for 12 weeks. All participants were examined for the acne severity index (ASI) and total acne lesions counting (TLC) at certain times during the study. Then, they stopped using them for four weeks. They also did not take the drug in the final four weeks of the study. Results: Forty-eight patients completed the study for 16 weeks; 40 (83.2) patients were female and the rest of them were male. The mean age and standard deviation were 25.62 ± 7.62 years. After 12 weeks, the percentage changes of comedones, inflammatory lesions, ASI and TLC were significantly reduced in both groups (p < 0.001). The percentage change of inflammatory lesions and ASI decrease was significantly higher in the group 1 (p = 0.03). There was no significant difference in the incidence of side effects between the two groups. There was a more significant decrease in sebum percentage change in the group 1 (p = 0.003). Conclusion: Myrtle lotion was effective and safe for the treatment of mild to moderate acne vulgaris. Copyright © Korean Pharmacopuncture Institut
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