Derivation of extracts from Persian Gulf sea cucumber (Holothuria leucospilota) and assessment of its antifungal effect

Sea cucumber is presented as a potential marine source of antimicrobial compounds. The purpose of this study is to evaluate antifungal effects of sea cucumber, Holothuria leucospilota, extracts on Aspergillus niger and Candida albicans. Methanol and chloroform extracts of the body wall, gonad and intestine of sea cucumber, H. leucospilota, collected from Persian Gulf, were evaluated for their antifungal activity against A. niger and C. albicans. The activity was determined using serial dilution method. Antifungal activity, minimum inhibitory concentration and minimum fungicidal concentration were evaluated by the different concentrations. Results showed that each of the extracts had antifungal effect at specified concentrations on the A. niger. All examined concentrations of Gonad methanol and intestine chloroform extracts had no inhibitory effect on C. albicans. Chloroform extracts of gonad and intestine had more fungicidal effect against A. niger compared with C. albicans. Gonad chloroform extracts showed more fungicidal effect on the C. albicans at concentrations of 2.5, 5 and 10 mg/ml. Sea cucumber extract can be considered as an antifungal agent in various industries such as medicine and pharmaceutical industry

Magnetic properties of the spin S=1/2S=1/2 Heisenberg chain with hexamer modulation of exchange

We consider the spin-1/2 Heisenberg chain with alternating spin exchange %on even and odd sites in the presence of additional modulation of exchange on odd bonds with period three. We study the ground state magnetic phase diagram of this hexamer spin chain in the limit of very strong antiferromagnetic (AF) exchange on odd bonds using the numerical Lanczos method and bosonization approach. In the limit of strong magnetic field commensurate with the dominating AF exchange, the model is mapped onto an effective $XXZ$ Heisenberg chain in the presence of uniform and spatially modulated fields, which is studied using the standard continuum-limit bosonization approach. In absence of additional hexamer modulation, the model undergoes a quantum phase transition from a gapped string order into the only one gapless L\"uttinger liquid (LL) phase by increasing the magnetic field. In the presence of hexamer modulation, two new gapped phases are identified in the ground state at magnetization equal to 1/3 and 2/3 of the saturation value. These phases reveal themselves also in magnetization curve as plateaus at corresponding values of magnetization. As the result, the magnetic phase diagram of the hexamer chain shows seven different quantum phases, four gapped and three gapless and the system is characterized by six critical fields which mark quantum phase transitions between the ordered gapped and the LL gapless phases.Comment: 21 pages, 5 figures, Journal of Physics: Condensed Matter, 24, 116002, (2012

Room temperature degradation of YBa2Cu3O(7-x) superconductors in varying relative humidity environments

An aging study was performed to determine the stability of YBa2Cu3O(7-x) ceramics in humid environments at 20 C. In this study, fired ceramic specimens were exposed to humidity levels ranging from 30.5 to 100 percent for 2-, 4-, and 6-week time intervals. After storage under these conditions, the specimens were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrical resistance measurements. At every storage condition evaluated, the fired ceramics were found to interact with H2O present in the surrounding environment, resulting in the decomposition of the YBa2Cu3O(7-x) phase. XRD data showed that BaCO3, CuO, and Y2BaCuO5 were present after aging and that the peak intensities of these impurity phases increased both with increasing humidity level and with increasing time of exposure. Additionally, SEM analyses of the ceramic microstructures after aging revealed the development of needle-like crystallites along the surface of the test specimens after aging. Furthermore, the superconducting transition temperature T(sub c) was found to decrease both with increasing humidity level and with increasing time of exposure. All the specimens aged at 30.5, 66, and 81 percent relative humidity exhibited superconducting transitions above 80 K, although these values were reduced by the exposure to the test conditions. Conversely, the specimens stored in direct contact with water (100 percent relative humidity) exhibited no superconducting transitions

Association of RS4784227-casc16 (Loc643714 locus) and RS4782447-ACSF3 polymorphisms and their association with breast cancer risk among iranian population

Peer reviewedPublisher PD

Free-fermion descriptions of parafermion chains and string-net models

Topological phases of matter remain a focus of interest due to their unique properties: fractionalization, ground-state degeneracy, and exotic excitations. While some of these properties can occur in systems of free fermions, their emergence is generally associated with interactions between particles. Here, we quantify the role of interactions in general classes of topological states of matter in one and two spatial dimensions, including parafermion chains and string-net models. Surprisingly, we find that certain topological states can be exactly described by free fermions, while others saturate the maximum possible distance from their optimal free-fermion description [C. J. Turner et al., Nat. Commun. 8, 14926 (2017)]. Our work opens the door to understanding the complexity of topological models by establishing new types of fermionization procedures to describe their low-energy physics, thus making them amenable to experimental realizations

Sense of coherence and coping strategies: How they influence quality of life in Iranian women with breast cancer

Aim: To investigate the mediation/moderation effect between Coping Behaviors (CBs) and Sense of Coherence (SOC) in the prediction of health-related quality of life (HRQoL) in breast cancer patients. Design: Cross-sectional. Methods: A total of 221 patients were included in this study. The 13-item Orientation to Life Questionnaire, Brief COPE and Functional Assessment of Cancer Therapy�Breast were investigated. Pearson's correlation coefficient and mediation/moderation analysis were performed. Results: Significant correlations were observed for SOC, active coping, acceptance, positive reframing (PR), planning, use of emotional support (UES), use of instrumental support, behaviour disengagement and self-blame with HRQoL. Except for planning and acceptance, SOC partially mediated the CBs' effect on HRQoL. The UES and PR's effects on HRQoL were significant at lower SOC levels and diminished at higher SOC levels. Conclusion: Practitioners can incorporate SOC and adaptive CBs, including PR and UES, into the rehabilitation programmes to improve HRQoL in patients. © 2021 The Authors. Nursing Open published by John Wiley & Sons Ltd

Biophysical and electrochemical studies of protein-nucleic acid interactions

This review is devoted to biophysical and electrochemical methods used for studying protein-nucleic acid (NA) interactions. The importance of NA structure and protein-NA recognition for essential cellular processes, such as replication or transcription, is discussed to provide background for description of a range of biophysical chemistry methods that are applied to study a wide scope of protein-DNA and protein-RNA complexes. These techniques employ different detection principles with specific advantages and limitations and are often combined as mutually complementary approaches to provide a complete description of the interactions. Electrochemical methods have proven to be of great utility in such studies because they provide sensitive measurements and can be combined with other approaches that facilitate the protein-NA interactions. Recent applications of electrochemical methods in studies of protein-NA interactions are discussed in detail

Synthetic biology to access and expand nature's chemical diversity

Bacterial genomes encode the biosynthetic potential to produce hundreds of thousands of complex molecules with diverse applications, from medicine to agriculture and materials. Accessing these natural products promises to reinvigorate drug discovery pipelines and provide novel routes to synthesize complex chemicals. The pathways leading to the production of these molecules often comprise dozens of genes spanning large areas of the genome and are controlled by complex regulatory networks with some of the most interesting molecules being produced by non-model organisms. In this Review, we discuss how advances in synthetic biology — including novel DNA construction technologies, the use of genetic parts for the precise control of expression and for synthetic regulatory circuits — and multiplexed genome engineering can be used to optimize the design and synthesis of pathways that produce natural products

The Magneto-Optical Response of Diluted Magnetic Semiconductor CdTe−Cd1−xMnxTeCdTe-Cd_{1-x}Mn_{x}Te Multi Quantum Wells in the Voigt Configuration

We have calculated the s- and p-polarized far infrared magnetoplasmon spectra of doped $CdTe-Cd_{1-x}Mn_{x}Te$ multi quantum wells in the presence of a static magnetic field up to 20 T parallel to the surface of the layers using a macroscopic model based on effective medium theory, using a novel approach which gives a good account of the data together with a clear physical interpretation of the various spectral features, such as the free carrier and optical phonon properties. The results show that the transverse optical modes (for the whole composition range, x = 0 to 1) are sensitive and change linearly with respect to the composition parameter. In p-polarized reflectivity the cyclotron resonance experiences a blue shift when the magnetic field strength increases. Also, the analysis of the dielectric tensor function and the Voigt dielectric function is used to determine the carriers' cyclotron effective masses (for both holes and electrons) as a function of composition. Furthermore, a modified random element iso-displacement approach has been extended for the multi layers to analyze the influence of the composition on the optical phonon response in the barrier layer