132 research outputs found

    On invariance functions in Relativity Theory

    Get PDF
    A new result for equivariant functions in terms of invariant functions in the case of Minkowski space is given. This generalizes the work of Hall and Wightman in the sense that only equivariance is required. In particular, it implies the possibility of defining physical magnitudes independently of the choice of the coordinate system, like the center of mass for relativistic particles

    CF2 transcription factor is involved in the regulation of Mef2 RNA levels, nuclei number and muscle fiber size

    Full text link
    This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. CF2 and Mef2 influence a variety of developmental muscle processes at distinct stages of development. Nevertheless, the exact nature of the CF2-Mef2 relationship and its effects on muscle building remain yet to be resolved. Here, we explored the regulatory role of CF2 in the Drosophila embryo muscle formation. To address this question and not having proper null CF2 mutants we exploited loss or gain of function strategies to study the contribution of CF2 to Mef2 transcription regulation and to muscle formation. Our data point to CF2 as a factor involved in the regulation of muscle final size and/or the number of nuclei present in each muscle. This function is independent of its role as a Mef2 collaborative factor in the transcriptional regulation of muscle-structural genes. Although Mef2 expression patterns do not change, reductions or increases in parallel in CF2 and Mef2 transcript abundance were observed in interfered and overexpressed CF2 embryos. Since CF2 expression variations yield altered Mef2 expression levels but with correct spatio-temporal Mef2 expression patterns, it can be concluded that only the mechanism controlling expression levels is de-regu-lated. Here, it is proposed that CF2 regulates Mef2 expression through a Feedforward Loop circuit.This work was supported by Ministerio de Economia y Competitividad español (MINECO) BFU2010-19551 to M

    A Cross-Sectional Study of Prisoners in Mexico City Comparing Prevalence of Transmissible Infections and Chronic Diseases with That in the General Population.

    Get PDF
    ObjectivesTo describe patterns of transmissible infections, chronic illnesses, socio-demographic characteristics and risk behaviors in Mexico City prisons, including in comparison to the general population, to identify those currently needing healthcare and inform policy.Materials and methodsA cross-sectional study among 17,000 prisoners at 4 Mexico City prisons (June to December 2010). Participation was voluntary, confidential and based on informed consent. Participants were tested for HIV, Hepatitis B & C, syphilis, hypertension, obesity, and, if at risk, glucose and cholesterol. A subset completed a questionnaire on socio-demographic characteristics and risk behaviors. Positive results were delivered with counseling and treatment or referral.Results76.8% (15,517/20,196) of men and 92.9% (1,779/1,914) of women participated. Complete data sets were available for 98.8%. The following prevalence data were established for transmissible infections: HIV 0.7%; syphilis: Anti-TP+/VDRL+ 2.0%; Hepatitis B: HBcAb 2.8%, HBsAg 0.15%; Anti-HCV 3.2%. Obesity: 9.5% men, 33.8% women. Compared with national age- and sex-matched data, the relative prevalence was greater for HIV and syphilis among women, HIV and Hepatitis C in men, and all infections in younger participants. Obesity prevalence was similar for women and lower among male participants. The prevalence of previously diagnosed diabetes and hypertension was lower. Questionnaire data (1,934 men, 520 women) demonstrated lower educational levels, increased smoking and substance use compared to national data. High levels of non-sterile tattooing, physical abuse and histories of sexual violence were found.ConclusionThe study identified that health screening is acceptable to Mexico City prisoners and feasible on a large-scale. It demonstrated higher prevalence of HIV and other infections compared to national data, though low rates compared to international data. Individual participants benefited from earlier diagnosis, treatment and support. The data collected will also enable the formulation of improved policy for this vulnerable group

    Mutations in MUSK causing congenital myasthenic syndrome impair MuSK–Dok-7 interaction

    Get PDF
    We describe a severe congenital myasthenic syndrome (CMS) caused by two missense mutations in the gene encoding the muscle specific receptor tyrosine kinase (MUSK). The identified MUSK mutations M605I and A727V are both located in the kinase domain of MuSK. Intracellular microelectrode recordings and microscopy studies of the neuromuscular junction conducted in an anconeus muscle biopsy revealed decreased miniature endplate potential amplitudes, reduced endplate size and simplification of secondary synaptic folds, which were consistent with postsynaptic deficit. The study also showed a striking reduction of the endplate potential quantal content, consistent with additional presynaptic failure. Expression studies in MuSK deficient myotubes revealed that A727V, which is located within the catalytic loop of the enzyme, caused severe impairment of agrin-dependent MuSK phosphorylation, aggregation of acetylcholine receptors (AChRs) and interaction of MuSK with Dok-7, an essential intracellular binding protein of MuSK. In contrast, M605I, resulted in only moderate impairment of agrin-dependent MuSK phosphorylation, aggregation of AChRs and interaction of MuSK with Dok-7. There was no impairment of interaction of mutants with either the low-density lipoprotein receptor-related protein, Lrp4 (a co-receptor of agrin) or with the mammalian homolog of the Drosophila tumorous imaginal discs (Tid1). Our findings demonstrate that missense mutations in MUSK can result in a severe form of CMS and indicate that the inability of MuSK mutants to interact with Dok-7, but not with Lrp4 or Tid1, is a major determinant of the pathogenesis of the CMS caused by MUSK mutations

    Structural evidence of quercetin multi-target bioactivity:A reverse virtual screening strategy

    Get PDF
    The ubiquitous flavonoid quercetin is broadly recognized for showing diverse biological and health-promoting effects, such as anti-cancer, anti-inflammatory and cytoprotective activities. The therapeutic potential of quercetin and similar compounds for preventing such diverse oxidative stress-related pathologies has been generally attributed to their direct antioxidant properties. Nevertheless, accumulated evidence indicates that quercetin is also able to interact with multiple cellular targets influencing the activity of diverse signaling pathways. Even though there are a number of well-established protein targets such as phosphatidylinositol 3 kinase and xanthine oxidase, there remains a lack of a comprehensive knowledge of the potential mechanisms of action of quercetin and its target space. In the present work we adopted a reverse screening strategy based on ligand similarity (SHAFTS) and target structure (idTarget, LIBRA) resulting in a set of predicted protein target candidates. Furthermore, using this method we corroborated a broad array of previously experimentally tested candidates among the predicted targets, supporting the suitability of this screening approach. Notably, all of the predicted target candidates belonged to two main protein families, protein kinases and poly [ADP-ribose] polymerases. They also included key proteins involved at different points within the same signaling pathways or within interconnected signaling pathways, supporting a pleiotropic, multilevel and potentially synergistic mechanism of action of quercetin. In this context we highlight the value of quercetin's broad target profile for its therapeutic potential in diseases like inflammation, neurodegeneration and cancer

    A telemedicine distributed system for cooperative medical diagnosis

    Get PDF
    Procceedings of: Eighteenth Annual Symposium on Computer Aplications in Medical Care, november 5-9, 1994, Washington, USA. Edited by Judy G. OzboltTelemedicine is changing the classicalform of health care delivery, dramatically increasing the number of new applications in which some type of distributed synchronous cooperation between health care professionals is required. This paper presents the design and development ofa telemedicine distributed system for cooperative medical diagnosis based on two new approaches: 1) a distributed layered architecture specially designed to add synchronous computer supported cooperative workfeatures either to new or existing medical applications; 2) the definition of a methodological procedure to design graphical user interfaces for telemedicine cooperative working scenarios. The cooperative work is supported by a collaborative toolkit that provides telepointing, window sharing, coordination and synchronization. Finally, we have implemented and installed the telemedicine system in clinical practice between two hospitals, providing teleconferencing facilities for cooperative decision support in haemodynamics studies. This specific implementation and a preliminary evaluation were accomplished under the Research Project FEST "Framework for European Services in Telemedicine" funded by the EU AIM Programme.This work is supported in part by EU - AIM FEST project no. A-201 1, and by grants CICYT TEMA TIC 92-1288-PB and TELEMEDICINA TIC 93-1279-E.Publicad

    Evaluation of the influence of pH modification on food proteins struc-ture by FT-IR and AFM

    Get PDF
    Objective: The aim of this study was to evaluate the influence of pH variation (3.6, 4.6 and 5.6) on morphometric parameters and the secondary structure of proteins (ovalbumin and gliadin). Design/methodology/approach: The arithmetic mean roughness (Ra) and agglomerate size (AS) of the proteins were analyzed by atomic force microscopy (AFM), while their secondary structure was analyzed by Fourier transform infrared spectroscopy (FT-IR), both at different pH. Subsequently, a correlation analysis of the morphometric changes of the proteins with their secondary structure was performed. Results: Highlighting that it was found that, protein agglomerate size is influenced by changes in β-sheets and turn conformations. Limitations on study/implications: Effect of pH variation (3.6, 4.6, and 5.6) on morphometric parameters and the secondary structure of proteins (ovalbumin and gliadin). Findings/conclusions: The novelty of this contribution consists in demonstrating that there is a close structure-functionality relationship between the morphometric parameters of proteins and their secondary structure, combining microscopy and spectroscopy techniques. This allows a clear and deep understanding of protein behavior to select the appropriate pH conditions to improve the properties of many foods.Objective: The aim of this study was to evaluate the influence of pH variation (3.6, 4.6 and 5.6) on morphometric parameters and the secondary structure of proteins (ovalbumin and gliadin). Design/methodology/approach: The arithmetic mean roughness (Ra) and agglomerate size (AS) of the proteins were analyzed by atomic force microscopy (AFM), while their secondary structure was analyzed by Fourier transform infrared spectroscopy (FT-IR), both at different pH. Subsequently, a correlation analysis of the morphometric changes of the proteins with their secondary structure was performed. Results: Highlighting that it was found that, protein agglomerate size is influenced by changes in β-sheets and turn conformations. Limitations on study/implications: Effect of pH variation (3.6, 4.6, and 5.6) on morphometric parameters and the secondary structure of proteins (ovalbumin and gliadin). Findings/conclusions: The novelty of this contribution consists in demonstrating that there is a close structure-functionality relationship between the morphometric parameters of proteins and their secondary structure, combining microscopy and spectroscopy techniques. This allows a clear and deep understanding of protein behavior to select the appropriate pH conditions to improve the properties of many foods

    Alert classification for the ALeRCE broker system: The real-time stamp classifier

    Get PDF
    We present a real-time stamp classifier of astronomical events for the Automatic Learning for the Rapid Classification of Events broker, ALeRCE. The classifier is based on a convolutional neural network, trained on alerts ingested from the Zwicky Transient Facility (ZTF). Using only the science, reference, and difference images of the first detection as inputs, along with the metadata of the alert as features, the classifier is able to correctly classify alerts from active galactic nuclei, supernovae (SNe), variable stars, asteroids, and bogus classes, with high accuracy (~94%) in a balanced test set. In order to find and analyze SN candidates selected by our classifier from the ZTF alert stream, we designed and deployed a visualization tool called SN Hunter, where relevant information about each possible SN is displayed for the experts to choose among candidates to report to the Transient Name Server database. From 2019 June 26 to 2021 February 28, we have reported 6846 SN candidates to date (11.8 candidates per day on average), of which 971 have been confirmed spectroscopically. Our ability to report objects using only a single detection means that 70% of the reported SNe occurred within one day after the first detection. ALeRCE has only reported candidates not otherwise detected or selected by other groups, therefore adding new early transients to the bulk of objects available for early follow-up. Our work represents an important milestone toward rapid alert classifications with the next generation of large etendue telescopes, such as the Vera C. Rubin Observatory.The authors acknowledge support from the National Agency of Research and Development’s Millennium Science Initiative through grant IC12009, awarded to the Millennium Institute of Astrophysics (RC, ER, CV, FF, PE, GP, FEB, IR, PSS, GC, SE, Ja, EC, DR, DRM, MC) and from the National Agency for Research and Development (ANID) grants: BASAL Center of Mathematical Modelling AFB-170001 (CV, FF, IR, ECN, CS, ECI) and Centro de Astrofísica y Tecnologías Afines AFB170002 (FEB, PSS, MC); FONDECYT Regular #1171678 (PE), #1200710 (FF), #1190818(FEB), #1200495 (FEB), #1171273 (MC), #1201793(GP); FONDECYT Postdoctorado #3200250 (PSS); FONDECYT Iniciación #11191130 (CV); Magíster Nacional 2019 #22190947 (ER). This work was funded in part by project CORFO 10CEII-9157 Inria Chile (PS). The authors acknowledge financial support from the Spanish Ministry of Science, Innovation, and Universities (MICIU) under the 2019 Ramón y Cajal program RYC2019- 027683 (LG)

    Risk behaviors of 15–21 year olds in Mexico lead to a high prevalence of sexually transmitted infections: results of a survey in disadvantaged urban areas

    Get PDF
    BACKGROUND: Due to the fact that adolescents are more likely to participate in high-risk behaviors, this sector of the population is particularly vulnerable to contracting sexually transmitted infections (STIs) and resultant health problems. METHODS: A survey was carried out among adolescents from poor homes in 204 small-urban areas of Mexico. Information was collected in relation to risk behaviors and socio-economic environment. A sub-group of the participants also provided blood and urine samples which were analyzed to detect sexually transmitted infections. RESULTS: The presence of Chlamydia was detected in nearly 8% of participants who had stated that they were sexually active (18%) and approximately 12% were positive for herpes type 2-specific antibodies. For both, a greater proportion of girls resulted positive compared to boys. The presence of these biological outcomes of sexual risk behavior was associated with other risk behaviors (smoking), but not with self-reported indicators of protected sex (reported use of condom during most recent sexual activity). CONCLUSION: The results presented in this study show a startlingly high prevalence of HSV-2 among sexually active Mexican adolescents in poor urban areas, suggesting that this group has participated to a great extent in risky sexual practices. The relationships between socioeconomic environment and adolescent risk behavior need to be better understood if we are to design preventive interventions that modify the determinants of risk behaviors
    corecore