Statistical properties of a localization-delocalization transition induced by correlated disorder

The exact probability distributions of the resistance, the conductance and the transmission are calculated for the one-dimensional Anderson model with long-range correlated off-diagonal disorder at E=0. It is proved that despite of the Anderson transition in 3D, the functional form of the resistance (and its related variables) distribution function does not change when there exists a Metal-Insulator transition induced by correlation between disorders. Furthermore, we derive analytically all statistical moments of the resistance, the transmission and the Lyapunov Exponent. The growth rate of the average and typical resistance decreases when the Hurst exponent $H$ tends to its critical value ($H_{cr}=1/2$) from the insulating regime. In the metallic regime $H\geq1/2$, the distributions become independent of size. Therefore, the resistance and the transmission fluctuations do not diverge with system size in the thermodynamic limit

Evaluation of Waterlogging Tolerance in Twenty-One Cultivars and Genotypes of Bread Wheat (Triticum Aestivum L.) and its Effect on some Physiological Characteristics of Shoot and Root System at the Three-Leaf Stage

IntroductionCovering a staggering 215 million hectares, wheat stands as the world's most extensively cultivated crop plant. Just like its botanical counterparts, wheat operates as an obligate aerobic organism, implying its reliance on absorbing oxygen from the surrounding environment to facilitate growth, proliferation, and the successful completion of its life cycle. Annual instances of waterlogging stress inflict harm upon wheat crops, attributed to inadequate irrigation practices, subpar drainage systems, uneven field leveling, elevated groundwater levels, the presence of unyielding impermeable layers, and bouts of intense, abrupt rainfall. This adverse impact is progressively escalating, potentially influenced by the ongoing shifts in climate patterns. Consequently, the adoption of resilient cultivars and the genetic enhancement of bread wheat assume critical importance. These strategies are aimed at augmenting the wheat's capacity to effectively cope with waterlogging stress, aligning it with the mounting demands of a burgeoning global population.To achieve these goals, it is necessary to understand the factors causing waterlogging stress damage in wheat and to know the mechanisms of tolerance in this plant. The survival of root terminal meristem cells under waterlogging stress conditions is very limited, and their ability to grow again after removing the stress is also restricted. Waterlogging stress leads to the death of primary roots and reduced growth of lateral roots in wheat. However, there is variation among wheat cultivars concerning these traits. Reduced access to oxygen hampers root growth and nutrient absorption, including nitrogen. Consequently, photosynthesis and carbohydrate availability decrease, further restricting root growth.Materials and MethodsAn outdoor pot experiment was conducted to investigate the effect of waterlogging stress on shoot and root dry matter, as well as some physiological characteristics. The experiment followed a split-plot design based on randomized complete blocks with three replications. The stress was applied at the three-leaf stage, and three control levels were used: no waterlogging stress, mild stress (48 hours of waterlogging stress), and severe stress (120 hours of waterlogging stress) as the main factors. Cultivars and genotypes were also included as secondary factors.During the stress period, the water level was maintained at approximately 5 cm above the soil level. The cultivation took place outdoors in plastic pots. Data analysis was performed using SAS software, and graphs were generated using Excel software. Comparisons between treatments were based on the standard error. After testing different models, the linear regression model was ultimately employed.Results and DiscussionMild and severe waterlogging stress resulted in a significant decrease in shoot dry matter of 14.06% and 38.37%, respectively, across all cultivars and genotypes. Different cultivars and genotypes exhibited varying responses to waterlogging stress. To further understand the reasons for these differences, among the 21 cultivars and genotypes, Mehrgan and Sarang cultivars, as well as ms 93-16 and ms 93-6 genotypes, were selected due to their contrasting tolerance levels and yield potential. These selected cultivars and genotypes were studied to analyze specific root traits.Amidst severe waterlogging stress, a significant 38% reduction in root dry matter and a corresponding 29% decrease in root volume were recorded when compared to stress-free conditions. This closely mirrored the decline evident in shoot dry matter. Evaluation of the susceptibility index during the three-leaf stage unveiled that sole resilience was exhibited by the Aflak cultivar. In contrast, the remaining cultivars and genotypes were stratified into semi-tolerant and semi-susceptible categories.Notably, regression analysis underscored that even brief periods of waterlogging stress ushered in a reduction in dry matter. Furthermore, the elongation of the waterlogging duration magnified this decrease in dry matter, thereby mitigating the disparities across various cultivars and genotypes.ConclusionIn general, cultivars that were able to sustain higher levels of photosynthetic activity during waterlogging stress demonstrated a lower percentage decrease in dry matter. Although the Mehrgan cultivar experienced a significant reduction in dry matter yield and fell into the semi-sensitive group, it consistently exhibited significantly higher dry matter yield compared to other cultivars and genotypes across all treatments.AcknowledgmentThe authors express their gratitude to the Agriculture Research Center of Khuzestan for providing the seeds, the Research Vice-Chancellor of the Shahid Chamran University of Ahvaz for covering the costs, and all the employees of the Department of Plant Production and Genetics

Reduced DNA damage in tumor spheroids compared to monolayer cultures exposed to ionizing radiation

Background: Several cell lines when cultured under proper condition can form three dimensional structures called multicellular tumor spheroids. Tumor spheroids are valuable in vitro models for studying physical and biological behavior of real tumors. A number of previous studies using a variety of techniques have shown no relationship between radiosensitivity and DNA strand breaks in monolayer and spheroid model of cell culture. Materials and Methods: In the present study, the radiosensitivity of cells grown as monolayer and spheroid were measured with colony assay and the role of DNA strand breaks in this sensitivity was examined using single cell gel electrophoresis assay also known as Comet assay. Results: In the present experiment, spheroids showed more radioresistance than monolayers asjudged by the number of colonies which they produced after radiation. Under the same experimental conditions, less level of DNA damage was detected in spheroids using "comet assay" technique. Conclusion: It was concluded that the loss of radioresistance which was observed in monolayer cultures might have been attributed to the higher level of DNA damage occurred in the cells

Experimental Indicators of Accretion Processes in Active Galactic Nuclei

Bright Active Galactic Nuclei are powered by accretion of mass onto the super massive black holes at the centers of the host galaxies. For fainter objects star formation may significantly contribute to the luminosity. We summarize experimental indicators of the accretion processes in Active Galactic Nuclei (AGN), i.e., observable activity indicators that allow us to conclude on the nature of accretion. The Galactic Center is the closest galactic nucleus that can be studied with unprecedented angular resolution and sensitivity. Therefore, here we also include the presentation of recent observational results on Sagittarius A* and the conditions for star formation in the central stellar cluster. We cover results across the electromagnetic spectrum and find that the Sagittarius A* (SgrA*) system is well ordered with respect to its geometrical orientation and its emission processes of which we assume to reflect the accretion process onto the super massive black hole.Comment: 16 pages, 4 figures, conference proceeding: Accretion Processes in Cosmic Sources - APCS2016 - 5-10 September 2016, Saint Petersburg, Russi

Drug-related mutational patterns in hepatitis B virus (HBV) reverse transcriptase proteins from Iranian treatment-Naïve chronic HBV patients

Background: Immunomodulators and Nucleotide analogues have been used globally for the dealing of chronic hepatitis B virus (HBV) infection. However, the development of drug resistance is a major limitation to their long-term effectiveness. Objectives: The aim of this study was to characterize the hepatitis B virus reverse transcriptase (RT) protein variations among Iranian chronic HBV carriers who did not receive any antiviral treatments. Materials and Methods: Hepatitis B virus partial RT genes from 325 chronic in active carrier patients were amplified and directly sequenced. Nucleotide/amino acid substitutions were identified compared to the sequences obtained from the database. Results: All strains belonging to genotype D.365 amino-acid substitutions were found. Mutations related to lamivudine, adefovir, telbivudine, and entecavir occurred in (YMDD) 4% (n = 13), (SVQ) 17.23% (n = 56), (M204I/V + L180M) 2.45% (n = 8) and (M204I) 2.76% (n = 9) of patients, respectively. Conclusions: RT mutants do occur naturally and could be found in HBV carriers who have never received antiviral therapy. However, mutations related to drug resistance in Iranian treatment-naïve chronic HBV patients were found to be higher than other studies published formerly. Chronic HBV patients should be monitored closely prior the commencement of therapy to achieve the best regimen option. © 2013, KOWSAR Corp

Dysregulation in multiple transcriptomic endometrial pathways is associated with recurrent implantation failure and recurrent early pregnancy loss

Overlapping disease aetiologies associated with multiple altered biological processes have been identified that change the endometrial function leading to recurrent implantation failure (RIF) and recurrent early pregnancy loss (REPL). We aimed to provide a detailed insight into the nature of the biological malfunction and related pathways of differentially expressed genes in RIF and REPL. Endometrial biopsies were obtained from 9 women experiencing RIF, REPL and control groups. Affymetrix microarray analysis was performed to measure the gene expression level of the endometrial biopsies. Unsupervised clustering of endometrial samples shows scattered distribution of gene expression between the RIF, REPL and control groups. 2556 and 1174 genes (p value 1.2) were significantly altered in the endometria of RIF and REPL patients’ group, respectively compared to the control group. Downregulation in Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of the differentially expressed genes (DEGs) in RIF and REPL including ribosome and oxidative phosphorylation pathways. Gene Ontology (GO) analysis revealed ribosomes and mitochondria inner membrane as the most significantly downregulated cellular component (CC) affected in RIF and REPL. Determination of the dysregulated genes and related biological pathways in RIF and REPL will be key in understanding their molecular pathology and of major importance in addressing diagnosis, prognosis, and treatment issue

Bone Mineral Density and Tibial Microarchitecture Changes in Division I Male and Female Cross - Country Runners

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Clinical and genetic spectrum of SCN2A-associated episodic ataxia

Background: Pathogenic variants in SCN2A are associated with various neurological disorders including epilepsy, autism spectrum disorder and intellectual disability. Few reports have recently described SCN2A-associated episodic ataxia (EA). Our study identifies its broader clinical and genetic spectrum, and describes pharmacological approaches. Results: We report 21 patients with SCN2A-associated EA, of which 9 are unpublished cases. The large majority of patients present with epileptic seizures (18/21, 86%), often starting within the first three months of life (12/18, 67%). In contrast, onset of episodic ataxia ranged from 10 months to 14 years of age. The frequency of EA episodes ranged from brief, daily events up to 1-2 episodes per year each lasting several weeks. Potential triggers include minor head traumas and sleep deprivation. Cognitive outcome is favorable in most patients with normal or mildly impaired cognitive development in 17/21 patients (81%). No clear genotype-phenotype correlations were identified in this cohort. However, two mutational hotspots were identified, i.e. 7/21 patients (33%) harbor the identical pathogenic variant p.A263V, whereas 5/21 (24%) carry pathogenic variants that affect the S4 segment and its cytoplasmic loop within the domain IV. In addition, we identified six novel pathogenic variants in SCN2A. While acetazolamide was previously reported as beneficial in SCN2A-associated EA in one case, our data show a conflicting response in 8 additional patients treated with acetazolamide: three of them profited from acetazolamide treatment, while 5/8 did not. Conclusions: Our study describes the heterogeneous clinical spectrum of SCN2A-associated EA, identifies two mutational hotspots and shows positive effects of acetazolamide in about 50%. (C) 2019 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.Peer reviewe