4,111 research outputs found

    A Note on the Edge Roman Domination in Trees

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    A subset XX of edges of a graph GG is called an \textit{edgedominating set} of GG if every edge not in XX is adjacent tosome edge in XX. The edge domination number γ(G)\gamma'(G) of GG is the minimum cardinality taken over all edge dominating sets of GG. An \textit{edge Roman dominating function} of a graph GG is a function f:E(G){0,1,2}f : E(G)\rightarrow \{0,1,2 \} such that every edgeee with f(e)=0f(e)=0 is adjacent to some edge ee' with f(e)=2.f(e') = 2.The weight of an edge Roman dominating function ff is the valuew(f)=eE(G)f(e)w(f)=\sum_{e\in E(G)}f(e). The edge Roman domination number of GG, denoted by γR(G)\gamma_R'(G), is the minimum weight of an edge Roman dominating function of GG. In this paper, we characterize trees with edge Roman domination number twice the edge domination number

    Possible co-existence of local itinerancy and global localization in a quasi-one-dimensional conductor

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    In the chain compound PrBa2_2Cu4_4O8_8 localization appears simultaneously with a dimensional crossover in the electronic ground state when the scattering rate in the chains exceeds the hopping rate between the chains. Here we report the discovery of a large, transverse magnetoresistance in PrBa2_2Cu4_4O8_8 in the localized regime. This result suggests a novel form of localization whereby electrons retain their metallic (quasi-one-dimensional) character over a microscopic length scale despite the fact that macroscopically, they exhibit localized (one-dimensional) behavior.Comment: 4 pages, 4 Figure

    Antioxidants: Positive or Negative Actors?

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    The term "antioxidant" is one of the most confusing definitions in biological/medical sciences. In chemistry, "antioxidant" is simply conceived "a compound that removes reactive species, mainly those oxygen-derived", while in a cell context, the conceptual definition of an antioxidant is poorly understood. Indeed, non-clinically recommended antioxidants are often consumed in large amounts by the global population, based on the belief that cancer, inflammation and degenerative diseases are triggered by high oxygen levels (or reactive oxygen species) and that through blocking reactive species production, organic unbalances/disorders can be prevented and/or even treated. The popularity of these chemicals arises in part from the widespread public mistrust of allopathic medicine. In fact, reactive oxygen species play a dual role in dealing with different disorders, since they may contribute to disease onset and/or progression but may also play a key role in disease prevention. Further, the ability of the most commonly used supplements, such as vitamins C, E, selenium, and herbal supplements to decrease pathologic reactive oxygen species is not clearly established. Hence, the present review aims to provide a nuanced understanding of where current knowledge is and where it should go.Antoni Sureda acknowledges the support of Institute of Health Carlos III (Project CIBEROBNCB12/03/30038). Natália Martins thank to Portuguese Foundation for Science and Technology (FCT–Portugal) for the Strategic project ref. UID/BIM/04293/2013 and “NORTE2020-Programa Operacional Regional do Norte” (NORTE-01-0145-FEDER-000012)

    Determinants of Early Marriage from Married Girls' Perspectives in Iranian Setting: A Qualitative Study

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    Early marriage is a worldwide problem associated with a range of health and social consequences for teenage girls. Designing effective health interventions for managing early marriage needs to apply the community-based approaches. However, it has received less attention from policymakers and health researchers in Iran. Therefore, the current study aimed to explore determinants of early marriage from married girls' perspectives. The study was conducted from May 2013 to January 2015 in Ahvaz, Iran. A purposeful sampling method was used to select fifteen eligible participants. Data were collected through face-to-face, semistructured interviews and were analyzed using the conventional content analysis approach. Three categories emerged from the qualitative data including "family structure," "Low autonomy in decision-making," and "response to needs." According to the results, although the participants were not ready to get married and intended to postpone their marriage, multiple factors such as individual and contextual factors propelled them to early marriage. Given that early marriage is a multifactorial problem, health care providers should consider a multidimensional approach to support and empower these vulnerable girls. � 2016 Simin Montazeri et al

    Management of Streptococcus mutans-Candida spp. Oral biofilms’ infections: Paving the way for effective clinical interventions

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    Oral diseases are considered the most common noncommunicable diseases and are related to serious local and systemic disorders. Oral pathogens can grow and spread in the oral mucosae and frequently in biomaterials (e.g., dentures or prostheses) under polymicrobial biofilms, leading to several disorders such as dental caries and periodontal disease. Biofilms harbor a complex array of interacting microbes, increasingly unapproachable to antimicrobials and with dynamic processes key to disease pathogenicity, which partially explain the gradual loss of response towards conventional therapeutic regimens. New drugs (synthesized and natural) and other therapies that have revealed promising results for the treatment or control of these mixed biofilms are presented and discussed here. A structured search of bibliographic databases was applied to include recent research. There are several promising new approaches in the treatment of Candida spp.–Streptococcus mutans oral mixed biofilms that could be clinically applied in the near future. These findings confirm the importance of developing effective therapies for oral Candida–bacterial infections.C.F.R. would like to acknowledge the UID/EQU/00511/2019 Project—Laboratory of Process Engineering, Environment, Biotechnology and Energy (LEPABE), financed by national funds through FCT/MCTES (PIDDAC). N.M. would like to thank the Portuguese Foundation for Science and Technology (FCT-Portugal) for the Strategic project ref. UID/BIM/04293/2013 and “NORTE2020—Northern Regional Operational Program” (NORTE-01-0145-FEDER-000012)

    Antibacterial potential of Saussurea obvallata petroleum ether extract: A spiritually revered medicinal plant

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    Uttarakhand Himalayan region holds Asteraceae or Compositae as the largest family of flowering, medicinal and aromatic plants. Species belonging to this family rises from low altitude to the alpine region. Among Asteraceae, Saussurea obvallata (DC.) Edgew. is widely used in several indigenous systems of medicine. Flowers, leaves and rhizomes of S. obvallata are used for several traditional, religious, therapeutic and ornamental purposes. Aim of this study was to determine the chemical composition and antibacterial efficacy of petroleum ether extract (PEE) of S. obvallata. Gas chromatography-mass spectrometry (GC-MS) analysis was used for identifying phytochemicals present in the plant extract. Furthermore, the PEE was assessed for in-vitro antibacterial activity against selected Gram positive and negative strains. Structure of squalene and \u3b1-linolenic acid methyl ester were identified in PEE by GC-MS analysis, by comparing the results obtained with NIST library and literature reports. PEE exhibited significant activity against Staphylococcus aureus, Escherichia coli, Bacillus cereus, Bacillus subtilis with IC50 value of 87.2 \ub1 1.6, 98.4 \ub1 1.1 and 90.2 \ub1 1.8 \u3bcg/ml, respectively. These results showed that squalene and a-linolenic acid derivative identified in S. obvallata may be responsible for the observed antibacterial activity. To the best of our knowledge, this is the first report focused on the chemical composition and antibacterial activity of S. obvallata

    Fragile three-dimensionality in the quasi-one-dimensional cuprate PrBa_2Cu_4O_8

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    In this article we report on the experimental realization of dimensional crossover phenomena in the chain compound PrBa2_2Cu4_4O8_8 using temperature, high magnetic fields and disorder as independent tuning parameters. In purer crystals of PrBa2_2Cu4_4O8_8, a highly anisotropic three-dimensional Fermi-liquid state develops at low temperatures. This metallic state is extremely susceptible to disorder however and localization rapidly sets in. We show, through quantitative comparison of the relevant energy scales, that this metal/insulator crossover occurs precisely when the scattering rate within the chain exceeds the interchain hopping rate(s), i.e. once carriers become confined to a single conducting element.Comment: 12 pages, 5 figures, published at http://www.iop.org/EJ/article/1367-2630/8/9/172/njp6_9_172.htm

    The evolving landscape of predictive biomarkers in immuno-oncology with a focus on spatial technologies.

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    Immunotherapies have shown long-lasting and unparalleled responses for cancer patients compared to conventional therapy. However, they seem to only be effective in a subset of patients. Therefore, it has become evident that a greater understanding of the tumor microenvironment (TME) is required to understand the nuances which may be at play for a favorable outcome to therapy. The immune contexture of the TME is an important factor in dictating how well a tumor may respond to immune checkpoint inhibitors. While traditional immunohistochemistry techniques allow for the profiling of cells in the tumor, this is often lost when tumors are analysed using bulk tissue genomic approaches. Moreover, the actual cellular proportions, cellular heterogeneity and deeper spatial distribution are lacking in characterisation. Advances in tissue interrogation technologies have given rise to spatially resolved characterisation of the TME. This review aims to provide an overview of the current methodologies that are used to profile the TME, which may provide insights into the immunopathology associated with a favorable outcome to immunotherapy
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