Quantum phase transition as an interplay of Kitaev and Ising interactions

We study the interplay between the Kitaev and Ising interactions on both ladder and two dimensional lattices. We show that the ground state of the Kitaev ladder is a symmetry-protected topological (SPT) phase, which is protected by a $\mathbb{Z}_2 \times \mathbb{Z}_2$ symmetry. It is confirmed by the degeneracy of the entanglement spectrum and non-trivial phase factors (inequivalent projective representations of the symmetries), which are obtained within infinite matrix-product representation of numerical density matrix renormalization group. We derive the effective theory to describe the topological phase transition on both ladder and two-dimensional lattices, which is given by the transverse field Ising model with/without next-nearest neighbor coupling. The ladder has three phases, namely, the Kitaev SPT, symmetry broken ferro/antiferromagnetic order and classical spin-liquid. The non-zero quantum critical point and its corresponding central charge are provided by the effective theory, which are in full agreement with the numerical results, i.e., the divergence of entanglement entropy at the critical point, change of the entanglement spectrum degeneracy and a drop in the ground-state fidelity. The central charge of the critical points are either c=1 or c=2, with the magnetization and correlation exponents being 1/4 and 1/2, respectively. In the absence of frustration, the 2D lattice shows a topological phase transition from the $\mathbb{Z}_2$ spin-liquid state to the long-range ordered Ising phase at finite ratio of couplings, while in the presence of frustration, an order-by-disorder transition is induced by the Kitaev term. The 2D classical spin-liquid phase is unstable against the addition of Kitaev term toward an ordered phase before the transition to the $\mathbb{Z}_2$ spin-liquid state.Comment: 16 pages, 18 figure

Investigating the level of moral distress and its related factors among nurses in mazandaran burn center

Background and purpose: Moral distress is a common phenomenon in nursing professional and burn nurses are constantly faced with making different moral decisions for patients who are in terrible conditions. Therefore, nurses in burn units experience moral distress as mental tension. This study was conducted to determine the severity of moral distress and the factors associated with that in burn nurses. Materials and methods: A descriptive- analytical study was conducted using census sampling on 172 nurses working in Mazandaran burn center, 2014. Data was collected through identifying demographic and occupational characteristics of the nurses (using relevant questionnaires) and Corley’s Moral Distress Scale. Data analysis was performed applying Mann-Whitney and Kruskal-Wallis test. Results: The mean score for moral distress was 105.65±52.39 which indicates a moderate level experienced by nurses. Kruskal-Wallis test showed a significant positive correlation between educational level and level of moral distress (P=0.011). There was no significant association between moral distress and other individual and professional characteristics (P>0.05). Conclusion: Moral distress is accompanied by many complications that have direct effects on nurses’ professional practice. Therefore, nurse managers should consider this issue and plan for programs on appropriate coping strategies. © 2015, Mazandaran University of Medical Sciences. All rights reserved

In vitro inhibition of growth in Saprolegnia sp. isolated from the eggs of Persian sturgeon Acipenser persicus (Pisces: Acipenseriformes) by Pseudomonas aeroginosa (PTCC:1430)

Saprolegnia is one of the most important agents decreasing the eggs survival rate in sturgeon hatcheries.There are some chemical substances for controlling the fungal infection of eggs. In this study, an attempt was made to introduce a germ negative bacterium, Pseudomonas aeroginosa (PTCC1430)(Persian Type Culture Collection) as a biocontrolling agent of water mold. Saprolegnia was isolated from the eggs of some infected Persian sturgeon, Acipenser persicus in a sturgeon hatchery and then was purified. P.aeroginosa was cultured in Potato dextrose Agar (PDB) media and then was prepared in 5 concentrations (103,104,105,106and107cfu.ml-1) while challenging with fungi in petri dishes under laboratory conditions.The results showed that by increasing the concentration of the bacteria in plates, hyphal growth of the fungi was reduced. The highest concentration of P. aeroginosa concentration (107) roughly stopped the -fungi growth and the Minimum Inhibitory Concentration (MIC) was 104cfu.m-l. Results in this study implied the potential of P. aeroginosa (PTCC1430) as a biological agent in controlling saprolegniosis

The Role of Microgravity in Cancer: A Dual-edge Sword

Since human beings could travel beyond the earth atmosphere, scientists started to investigate the effect of microgravity on human cells. Microgravity has different effects on normal and cancer cells, but the related mechanisms are not well-known till now. The aim of the present review is to focus on the consequences of exposing the cancer cells to reduced gravity. Some cancer cells organize three-dimensional structures under microgravity. Obviously, microgravity is an external stress, which can affect cell proliferation, apoptosis, cytoskeleton and signaling pathways. In addition, it touches immune-related components, regulates immune responses, and implicates immune cell activation. Low mutation aggregation and cancer rate in astronauts may lead to use microgravity as a therapeutic approach. However, it reduces the invasion and migration in some types of cancer cells, triggers the oncogenic signaling pathways including KRAS, and inhibits proliferation in normal lymphocytes. In conclusion, using microgravity as a therapeutic method in cancer treatment needs to be more investigated on both cancer and normal cells, and might not become true in the near future

Change in bone mineral density in post menopausal women with rheumatoid arthritis

Introduction: Low bone mass is a serious complication of post menopausal women with rheumatoid arthritis. We determined the Change in Bone Mineral Density in postmenopausal women with rheumatoid arthritis. Methods: This retrospective cohort study was carried out on consecutive postmenopausal women with rheumatoid arthritis who were referred to the Azar 5th teaching hospital affiliated to Golestan University of Medical Sciences, North of Iran in 2009. The required data were gathered from the patients' medical records. The data were analyzed using SPSS software and statistical tests. Results: We studied 98 postmenopausal women with rheumatoid arthritis. Mean number of years since menopause and mean duration of disease were 9.39 and 5.13 respectively. T Score mean in femoral neck and lumbar spines was -1.45±1.26 and -2.45±1.44 respectively. The overall prevalence of osteoporosis at both the lumbar spine and femoral neck was 13.3. We have found a significant correlation between age, duration of disease, duration of menopause and bone mineral density (P-Value<0.01). Conlusion: Our results indicate a negative effect of age, number of years since menopause and duration of disease on bone mineral density. So, BMD should be measured in high risk women prior to the implementation of any treatment or prevention program

Testicular expression of TDRD1, TDRD5, TDRD9 and TDRD12 in azoospermia.

BACKGROUND: Tudor domain-containing proteins (TDRDs) play a critical role in piRNA biogenesis and germ cell development. piRNAs, small regulatory RNAs, act by silencing of transposons during germline development and it has recently been shown in animal model studies that defects in TDRD genes can lead to sterility in males. METHODS: Here we evaluate gene and protein expression levels of four key TDRDs (TDRD1, TDRD5, TDRD9 and TDRD12) in testicular biopsy samples obtained from men with obstructive azoospermia (OA, n = 29), as controls, and various types of non-obstructive azoospermia containing hypospermatogenesis (HP, 28), maturation arrest (MA, n = 30), and Sertoli cell-only syndrome (SCOS, n = 32) as cases. One-way ANOVA test followed by Dunnett's multiple comparison post-test was used to determine inter-group differences in TDRD gene expression among cases and controls. RESULTS: The results showed very low expression of TDRD genes in SCOS specimens. Also, the expression of TDRD1 and TDRD9 genes were lower in MA samples compared to OA samples. The expression of TDRD5 significantly reduced in SCOS, MA and HP specimens than the OA specimens. Indeed, TDRD12 exhibited a very low expression in HP specimens in comparison to OA specimens. All these results were confirmed by Western blot technique. CONCLUSION: TDRDs could be very important in male infertility, which should be express in certain stages of spermatogenesis

Evaluation of the spatial arrangement of Purkinje cells in ataxic rat’s cerebellum after Sertoli cells transplantation

Background: Purkinje cells (PCs) pathology is important in cerebellar disorders like ataxia. The spatial arrangement of PCs after different treatments has not been studied extensively. Immunohistochemistry (IHC) analysis of cerebellum can give a proper tool for explaining the pathophysiology of PCs in ataxia. Here we stereologically analysed the 3-dimensional spatial arrangement of PCs in the cerebellum of rats after ataxia induction with 3-acetylpyridine (3-AP). Materials and methods: Ataxia was induced in rats by intraperitoneal injection of 3-AP (65 mg/kg). Spatial arrangement of PCs for differences in ataxic rats with (3-AP-SC) or without (3-AP) Sertoli cells (SCs) transplantation was evaluated using second-order stereology. The IHC method by using antibodies to anti-calbindin in the cerebellum was applied. Results: Our results showed that a random arrangement is at larger distances between PCs in 3-AP and 3-Ap-SC groups. Therefore the PCs are not normally arranged after 3-AP and SCs transplantation stored the spatial arrangements of the cells after ataxia induction in rats. IHC analyse shows that number of PCs was significantly improved after the SC transplantation. Conclusions: Segregation of PCs can be observed at some areas in the ataxic rats’ cerebellum. However, the spatial arrangement of PCs was unchanged in SCs transplanted rats. (Folia Morphol 2018; 77, 2: 194–200

A graph search algorithm: Optimal placement of passive harmonic filters in a power system

The harmonic in distribution systems becomes an important problem due to an increase in nonlinear loads. This paper presents a new approach based on a graph algorithm for optimum placement of passive harmonic filters in a multi-bus system, which suffers from harmonic current sources. The objective of this paper is to minimize the network loss, the cost of the filter and the total harmonic distortion of voltage, and also enhances voltage profile at each bus effectively. Four types of sub-graph have been used for search space of optimization. The method handles standard capacitor sizes in planning filters and associated costs. In this paper, objective function is not differential but eases solving process. The IEEE 30 bus test system is used for the placement of passive filter. The simulation has been done to show applicability of the proposed method. Simulation results prove that the method is effective and suitable for the passive filter planning in a power system

Female gender and Helicobacter pylori infection, the most important predisposition factors in a cohort of gastric cancer: A longitudinal study

Background: Gastric cancer (GC) is one of the most common Cancers in the world and Helicobacter pylori (HP) infection is considered a causative factor. The aim of this study was to determine the characteristics and the associated factors of (GC) in a small cohort. Methods: Overall, 54 patients with diagnosed gastric cancer were followed-up at the Department of Gastroenterology&Hepatology at Baqiyatallah University of Medical Sciences. 37 (68.5) of them were positive for H pylori infection in histopathological evaluations. Univariate and multivariate regression analyses were used to determine the associations of demographic features and HP infection status with GC characteristics and prognosis. Results: Univariate analysis showed female gender (odds ratio (OR): 6.53; 95 confidence interval (95CI): 1.59-26.8; P=0.008), and illiteracy (compared to intermediate education; OR: 5.9, 95CI: 1.37-25.43; p=0.05) were associated significantly with higher rate of HP infection. After a mean±SD follow-up duration of 254±329 months, only female gender was significantly associated with HP infection in GC (OR:4.56; 95 CI: 1.0-21.76; P=0.05). H pylori positive patients had significantly higher grade of GC (OR: 3.97; 95 CI: 1.0-16.16; P=0.05), and a trend toward greater GC stage (OR: 4.46, 95 CI: 9.39-21.23; p=0.06). There was no association between survival rate and H pylori infection. Conclusion: In the current study, we found a significant association of female gender with GN and an association of higher grade of GC with female gender. These findings may indicate a sex disparity in susceptibility to HP infection regarding GC future studies of larger populations are recommended