1,899 research outputs found

    Effects of Molecular Crowding in Actin Polymerization

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    Topological properties of punctual Hilbert schemes of almost-complex fourfolds (I)

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    In this article, we study topological properties of Voisin's punctual Hilbert schemes of an almost-complex fourfold XX. In this setting, we compute their Betti numbers and construct Nakajima operators. We also define tautological bundles associated with any complex bundle on XX, which are shown to be canonical in KK-theory

    MAB21L2, a vertebrate member of the Male-abnormal 21 family, modulates BMP signaling and interacts with SMAD1

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    BACKGROUND: Through in vivo loss-of-function studies, vertebrate members of the Male abnormal 21 (mab-21) gene family have been implicated in gastrulation, neural tube formation and eye morphogenesis. Despite mounting evidence of their considerable importance in development, the biochemical properties and nature of MAB-21 proteins have remained strikingly elusive. In addition, genetic studies conducted in C. elegans have established that in double mutants mab-21 is epistatic to genes encoding various members of a Transforming Growth Factor beta (TGF-beta) signaling pathway involved in the formation of male-specific sensory organs. RESULTS: Through a gain-of-function approach, we analyze the interaction of Mab21l2 with a TGF-beta signaling pathway in early vertebrate development. We show that the vertebrate mab-21 homolog Mab21l2 antagonizes the effects of Bone Morphogenetic Protein 4 (BMP4) overexpression in vivo, rescuing the dorsal axis and restoring wild-type distribution of Chordin and Xvent2 transcripts in Xenopus gastrulae. We show that MAB21L2 immunoprecipitates in vivo with the BMP4 effector SMAD1, whilst in vitro it binds SMAD1 and the SMAD1-SMAD4 complex. Finally, when targeted to an heterologous promoter, MAB21L2 acts as a transcriptional repressor. CONCLUSIONS: Our results provide the first biochemical and cellular foundation for future functional studies of mab-21 genes in normal neural development and its pathological disturbances

    Effects of Abrupt Variations of Solar Wind Dynamic Pressure on the High-Latitude Ionosphere

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    We show the results of a statistical study on the effects in the high-latitude ionosphere of abrupt variations of solar wind dynamic pressure, using Super Dual Auroral Radar Network (SuperDARN) data in both hemispheres. We find that, during periods of quiet ionospheric conditions, the amount of radar backscatter increases when a variation in the dynamic pressure occurs, both positive (increase of the pressure) and negative (decrease of the pressure). We also investigate the behaviour of the Cross-Polar Cap Potential (CPCP) during pressure variations and show preliminary results

    A multi-modal intervention for Activating Patients at Risk for Osteoporosis (APROPOS): Rationale, design, and uptake of online study intervention material

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    OBJECTIVE: To develop an innovative and effective educational intervention to inform patients about the need for osteoporosis treatment and to determine factors associated with its online uptake. METHODS: Postmenopausal women with a prior fracture and not currently using osteoporosis therapy were eligible to be included in the Activating Patients at Risk for OsteoPOroSis (APROPOS). Four nominal groups with a total of 18 racially/ethnically diverse women identified osteoporosis treatment barriers. We used the Information, Motivation, Behavior Skills conceptual model to develop a direct-to-patient intervention to mitigate potentially modifiable barriers to osteoporosis therapy. The intervention included videos tailored by participants\u27 race/ethnicity and their survey responses: ranked barriers to osteoporosis treatment, deduced barriers to treatment, readiness to behavior change, and osteoporosis treatment history. Videos consisted of storytelling narratives, based on osteoporosis patient experiences and portrayed by actresses of patient-identified race/ethnicity. We also delivered personalized brief phone calls followed by an interactive voice-response phone messages aimed to promote uptake of the videos. RESULTS: To address the factors associated with online intervention uptake, we focused on participants assigned to the intervention arm (n = 1342). These participants were 92.9% Caucasian, with a mean (SD) age 74.9 (8.0) years and the majority (77.7%) had some college education. Preference for natural treatments was the barrier ranked #1 by most (n = 130; 27%), while concern about osteonecrosis of the jaw was the most frequently reported barrier (at any level; n = 322; 67%). Overall, 28.1% (n = 377) of participants in the intervention group accessed the videos online. After adjusting for relevant covariates, the participants who provided an email address had 6.07 (95% CI 4.53-8.14) higher adjusted odds of accessing their online videos compared to those who did not. CONCLUSION: We developed and implemented a novel tailored multi-modal intervention to improve initiation of osteoporosis therapy. An email address provided on the survey was the most important factor independently associated with accessing the intervention online. The design and uptake of this intervention may have implications for future studies in osteoporosis or other chronic diseases

    An ArsR/SmtB family member regulates arsenic resistance genes unusually arranged in Thermus thermophilus HB27.

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    Arsenic resistance is commonly clustered in ars operons in bacteria; main ars operon components encode an arsenate reductase, a membrane extrusion protein, and an As-sensitive transcription factor. In the As-resistant thermophile Thermus thermophilus HB27, genes encoding homologues of these proteins are interspersed in the chromosome. In this article, we show that two adjacent genes, TtsmtB, encoding an ArsR/SmtB transcriptional repressor and, TTC0354, encoding a Zn2+/Cd2+-dependent membrane ATPase are involved in As resistance; differently from characterized ars operons, the two genes are transcribed from dedicated promoters upstream of their respective genes, whose expression is differentially regulated at transcriptional level. Mutants defective in TtsmtB or TTC0354 are more sensitive to As than the wild type, proving their role in arsenic resistance. Recombinant dimeric TtSmtB binds in vitro to both promoters, but its binding capability decreases upon interaction with arsenate and, less efficiently, with arsenite. In vivo and in vitro experiments also demonstrate that the arsenate reductase (TtArsC) is subjected to regulation by TtSmtB. We propose a model for the regulation of As resistance in T. thermophilus in which TtSmtB is the arsenate sensor responsible for the induction of TtArsC which generates arsenite exported by TTC0354 efflux protein to detoxify cells

    The control of abstinence in the treatment of alcohol dependence: the use of Acamprosate in relapse prevention

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    "The alcoholism can also deal with drug treatments." This is the message that emerges from the press conference of presentation of Campral, trade name of acamprosate, a neuromodulator specifically indicated in the maintenance of abstinence in alcohol-dependent patients.Alcoholism is a disease characterized by: craving, loss of control, tolerance and physical dependence.For many years the prevention of relapse in use of alcohol after detoxification was supported almost exclusively by psychosocial procedures and techniques with modest success. Treatment with acamprosate is a valid tool to complement psychotherapy as it does not cause addiction, abuse or withdrawal of its suspension and does not interfere with other medications that patients often alcoholics must take.To evaluate the effectiveness, our study evaluated the effects of Acamprosate compared to GHB in clinical-physiological and social health in a way indicators of a possible therapeutic success in terms of abstinence from alcohol and social reintegration. The hypothesis of the project is that pharmacotherapy anticraving with acamprosate integrated with psycho-social support, can reduce relapse in alcohol together with the reduction of the risk of abuse arising from the use of GHB. This work purports to be an account of 11 months of observation of patients treated with acamprosate. Results: A total of 36 patients were observed, of which 5, 4 men and 1 woman at the Ser.T Alcamo and 31, 21 men and 10 women at the Ser.T of Palermo. In the fight against alcoholism, this therapy with acamprosate offers significant potential: decreases, in fact, the incidence, severity and frequency of relapses (Fig. 1). As regards the craving, during the period of treatment with acamprosate, there has been a change, in the sense of reduction, of craving for alcohol: if before therapy was in 68% of cases, medium-high, becomes after 3-4 months after therapy in low-nil in 89% of patients observed. It has been recorded that, after 3-4 months after receiving acamprosate, the clinical picture of the patient is greatly improved by referring to biological markers (Fig. 2). Conclusions: The study shows that treatment with acamprosate is an exciting opportunity within a project of integrated care for the treatment of alcohol addiction. The acamprosate may also be used early in the pharmacological treatment of dependence on alcohol to prevent the appearance of excitability neuronal associated abstinence.On the other hand, its use must have a duration sufficient to allow neuronal excitability to normalize in the most enduring possible: the treatment, in fact, is recommended for one year. In any case, the use can be continued even in the face of relapses, with the aim to reduce the frequency or severity.In particular, the strong point seems to be the ability for the user to experience a new sense of normalcy and to remove the desire for significant periods of alcohol

    Optimal transport on wireless networks

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    We present a study of the application of a variant of a recently introduced heuristic algorithm for the optimization of transport routes on complex networks to the problem of finding the optimal routes of communication between nodes on wireless networks. Our algorithm iteratively balances network traffic by minimizing the maximum node betweenness on the network. The variant we consider specifically accounts for the broadcast restrictions imposed by wireless communication by using a different betweenness measure. We compare the performance of our algorithm to two other known algorithms and find that our algorithm achieves the highest transport capacity both for minimum node degree geometric networks, which are directed geometric networks that model wireless communication networks, and for configuration model networks that are uncorrelated scale-free networks.Comment: 5 pages, 4 figure
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