1,556 research outputs found

    The complete mitochondrial genome of the enigmatic bigheaded turtle (Platysternon): description of unusual genomic features and the reconciliation of phylogenetic hypotheses based on mitochondrial and nuclear DNA

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    BACKGROUND: The big-headed turtle (Platysternon megacephalum) from east Asia is the sole living representative of a poorly-studied turtle lineage (Platysternidae). It has no close living relatives, and its phylogenetic position within turtles is one of the outstanding controversies in turtle systematics. Platysternon was traditionally considered to be close to snapping turtles (Chelydridae) based on some studies of its morphology and mitochondrial (mt) DNA, however, other studies of morphology and nuclear (nu) DNA do not support that hypothesis. RESULTS: We sequenced the complete mt genome of Platysternon and the nearly complete mt genomes of two other relevant turtles and compared them to turtle mt genomes from the literature to form the largest molecular dataset used to date to address this issue. The resulting phylogeny robustly rejects the placement of Platysternon with Chelydridae, but instead shows that it is a member of the Testudinoidea, a diverse, nearly globally-distributed group that includes pond turtles and tortoises. We also discovered that Platysternon mtDNA has large-scale gene rearrangements and possesses two, nearly identical, control regions, features that distinguish it from all other studied turtles. CONCLUSION: Our study robustly determines the phylogenetic placement of Platysternon and provides a well-resolved outline of major turtle lineages, while demonstrating the significantly greater resolving power of comparing large amounts of mt sequence over that of short fragments. Earlier phylogenies placing Platysternon with chelydrids required a temporal gap in the fossil record that is now unnecessary. The duplicated control regions and gene rearrangements of the Platysternon mtDNA probably resulted from the duplication of part of the genome and then the subsequent loss of redundant genes. Although it is possible that having two control regions may provide some advantage, explaining why the control regions would be maintained while some of the duplicated genes were eroded, examples of this are rare. So far, duplicated control regions have been reported for mt genomes from just 12 clades of metazoans, including Platysternon

    Comparing In-Person and Telepractice Service Delivery for Spoken Language Production and Comprehension Using the National Outcomes Measurement System

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    The American Speech-Language-Hearing Association (ASHA) developed the National Outcomes Measurement System for aggregating standardized patient outcomes. Outcomes are standardized using Functional Communication Measures (FCM), scales designed to describe communicative function across specific areas of clinical need. This investigation compared in-person and telepractice service delivery for children in elementary school settings who received treatment targeting the FCM categories of either “spoken language production” or “spoken language comprehension.” De-identified cases were secured from ASHA’s NOMS database and the database of a private e-learning provider that implemented the NOMS format. There were minimal significant differences in the median change scores between the traditional and telepractice interventions. These results support comparable treatment outcomes between in-person service delivery and telepractice for treatment of children exhibiting impaired spoken language production or spoken language comprehension in an elementary school settin

    Choosing the right path: enhancement of biologically relevant sets of genes or proteins using pathway structure

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    A method is proposed that finds enriched pathways relevant to a studied condition, using molecular and network data

    Electrospun Nano-fibers for biomedical and tissue engineering applications: A comprehensive review

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    Pharmaceutical nano-fibers have attracted widespread attention fromresearchers for reasons such as adaptability of the electro-spinning process and ease of production. As a flexible method for fabricating nano-fibers, electro-spinning is extensively used. An electro-spinning unit is composed of a pump or syringe, a high voltage current supplier, a metal plate collector and a spinneret. Optimization of the attained nano-fibers is undertaken through manipulation of the variables of the process and formulation, including concentration, viscosity, molecular mass, and physical phenomenon, as well as the environmental parameters including temperature and humidity. The nano-fibers achieved by electro-spinning can be utilized for drug loading. The mixing of two or more medicines can be performed via electro-spinning. Facilitation or inhibition of the burst release of a drug can be achieved by the use of the electro-spinning approach. This potential is anticipated to facilitate progression in applications of drug release modification and tissue engineering (TE). The present review aims to focus on electro-spinning, optimization parameters, pharmacological applications, biological characteristics, and in vivo analyses of the electro-spun nano-fibers. Furthermore, current developments and upcoming investigation directions are outlined for the advancement of electro-spun nano-fibers for TE. Moreover, the possible applications, complications and future developments of these nano-fibers are summarized in detail. © 2020 by the authors

    Calibration uncertainty in molecular dating analyses: there is no substitute for the prior evaluation of time priors

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    Calibration is the rate-determining step in every molecular clock analysis and, hence, considerable effort has been expended in the development of approaches to distinguish good from bad calibrations. These can be categorized into a priori evaluation of the intrinsic fossil evidence, and a posteriori evaluation of congruence through cross-validation. We contrasted these competing approaches and explored the impact of different interpretations of the fossil evidence upon Bayesian divergence time estimation. The results demonstrate that a posteriori approaches can lead to the selection of erroneous calibrations. Bayesian posterior estimates are also shown to be extremely sensitive to the probabilistic interpretation of temporal constraints. Furthermore, the effective time priors implemented within an analysis differ for individual calibrations when employed alone and in differing combination with others. This compromises the implicit assumption of all calibration consistency methods, that the impact of an individual calibration is the same when used alone or in unison with others. Thus, the most effective means of establishing the quality of fossil-based calibrations is through a priori evaluation of the intrinsic palaeontological, stratigraphic, geochronological and phylogenetic data. However, effort expended in establishing calibrations will not be rewarded unless they are implemented faithfully in divergence time analyses

    Differences in Cervical Cancer Screening Knowledge and Practices by HIV Status and Geographic Location: Implication for Program Implementation in Zambia

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    The knowledge and perceptions of cervical cancer among HIV negative and positive women, aged 25-49 years, from rural and urban locations in  Zambia was systematically accessed in this study to determine any  differences. Data were coded and analyzed using NVivo software. Compared to HIV negative women, HIV positive women had more accurate information about cervical cancer. They were more likely to cite male circumcision as the best approach to cervical cancer prevention. HPV infection was more commonly mentioned as a risk factor among HIV positive women. However, HIV positive women displayed little knowledge about HPV being the major cause of cervical cancer. Among HIV positive women, lack of time was the major screening barrier cited while HIV negative women mentioned being symptomatic as a determinant for early detection. Compared to rural residents, urban residents cited a wider range of cervical cancer information sources, including media and workplace although all of the participants who stated that they had no knowledge of cervical cancer were urban residents. Overall, knowledge and perceptions of cervical cancer among study  participants was high, although differences exist between subgroups. Sharing accurate and standardized information on cervical cancer would improve participation in cervical cancer screening services. (Afr J Reprod Health 2018; 22[4]:92-101).Keywords: Cervical cancer, screening, HIV status, cervical cancer knowledge and perception, rural and urban location, Zambi

    Antioxidant, antimicrobial and antiviral properties of herbal materials

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    Recently, increasing public concern about hygiene has been driving many studies to investigate antimicrobial and antiviral agents. However, the use of any antimicrobial agents must be limited due to their possible toxic or harmful effects. In recent years, due to previous antibiotics’ lesser side effects, the use of herbal materials instead of synthetic or chemical drugs is increasing. Herbal materials are found in medicines. Herbs can be used in the form of plant extracts or as their active components. Furthermore, most of the world’s populations used herbal materials due to their strong antimicrobial properties and primary healthcare benefits. For example, herbs are an excellent material to replace nanosilver as an antibiotic and antiviral agent. The use of nanosilver involves an ROS-mediated mechanism that might lead to oxidative stress-related cancer, cytotoxicity, and heart diseases. Oxidative stress further leads to increased ROS production and also delays the cellular processes involved in wound healing. Therefore, existing antibiotic drugs can be replaced with biomaterials such as herbal medicine with high antimicrobial, antiviral, and antioxidant activity. This review paper highlights the antibacterial, antiviral, and radical scavenger (antioxidant) properties of herbal materials. Antimicrobial activity, radical scavenger ability, the potential for antimicrobial, antiviral, and anticancer agents, and efficacy in eliminating bacteria and viruses and scavenging free radicals in herbal materials are discussed in this review. The presented herbal antimicrobial agents in this review include clove, portulaca, tribulus, eryngium, cinnamon, turmeric, ginger, thyme, pennyroyal, mint, fennel, chamomile, burdock, eucalyptus, primrose, lemon balm, mallow, and garlic, which are all summarized. © 2020 by the authors. Licensee MDPI, Basel, Switzerland
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