254 research outputs found

    Polarimetry of an Intermediate-age Open Cluster: NGC 5617

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    We present polarimetric observations in the UBVRI bands of 72 stars located in the direction of the medium age open cluster NGC 5617. Our intention is to use polarimetry as a tool membership identification, by building on previous investigations intended mainly to determine the cluster's general characteristics rather than provide membership suitable for studies such as stellar content and metallicity, as well as study the characteristics of the dust lying between the Sun and the cluster. The obsevations were carried out using the five-channel photopolarimeter of the Torino Astronomical Observatory attached to the 2.15m telescope at the Complejo Astron\'omico El Leoncito (CASLEO; Argentina. We are able to add 32 stars to the list of members of NGC 5617, and review the situation for others listed in the literature. In particular, we find that five blue straggler stars in the region of the cluster are located behind the same dust as the member stars are and we confirm the membership of two red giants. The proposed polarimetric memberships are compared with those derived by photometric and kinematical methods, with excellent results. Among the observed stars, we identify 10 with intrinsic polarization in their light. NGC 5617 can be polarimetrically characterized with Pmax=4.40P_{max}= 4.40% and θv=73.1 \theta_{v}= 73^\circ.1. The spread in polarization values for the stars observed in the direction of the cluster seems to be caused by the uneven distribution of dust in front of the cluster's face. Finally, we find that in the direction of the cluster, the interstellar medium is apparently free of dust, from the Sun's position up to the Carina-Sagittarius arm, where NGC 5617 seems to be located at its farthest border

    Optical polarization observations in the Scorpius region: NGC 6124

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    We have obtained optical multicolour (UBVRI) linear polarimetric data for 46 of the brightest stars in the area of the open cluster NGC 6124 in order to investigate the properties of the interstellar medium (ISM) that lies along the line of sight toward the cluster. Our data yield a mean polarization efficiency of PV/EBV=3.1±P_V/E_{B-V}=3.1\pm0.62, i.e., a value lower than the polarization produced by the ISM with normal efficiency for an average color excess of EBV=0.80E_{B-V}=0.80 as that found for NGC 6124. Besides, the polarization shows an orientation of θ8\theta \sim 8^\circ.1 which is not parallel to the Galactic Disk,an effect that we think may be caused by the Lupus Cloud. Our analysis also indicates that the observed visual extinction in NGC 6124 is caused by the presence of three different absorption sheets located between the Sun and NGC 6124. The values of the internal dispersion of the polarization (ΔPV1.3\Delta P_V\sim 1.3% ) and of the colour excess (ΔEBV0.29\Delta E_{B-V}\sim 0.29 mag) for the members of NGC 6124 seem to be compatible with the presence of an intra-cluster dust component. Only six stars exhibit some evidence of intrinsic polarization.Our work also shows that polarimetry provides an excellent tool to distinguish between member and non-member stars of a cluster

    Endoscopic Transorbital Approach for Spheno-Orbital Tumors: Case Series and Systematic Review of Literature

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    Background: Transorbital neuroendoscopic surgery (TONES) comprises a group of approaches with indications expanding from orbital tumors to more complex skull base lesions. We analyzed the role of the endoscopic transorbital approach (eTOA) for spheno-orbital tumors, reporting the results of our clinical series and of a systematic review of the literature. Materials and Methods: All patients operated on from 2016 to 2022 at our institution for a spheno-orbital tumor through an eTOA were included in a clinical series, and a systematic review of the literature was performed. Results: Our series consisted of 22 patients (16 females, mean age 57 ± 13 years). Gross tumor removal was achieved in 8 patients (36.4%) after the eTOA and in 11 (50.0%) after a multistaged strategy combining the eTOA with the endoscopic endonasal approach. Complications included 1 chronic subdural hematoma and 1 permanent extrinsic ocular muscle deficit. Patients were discharged after 2.4 ± 1.3 days. The most common histotype was meningioma (86.4%). Proptosis improved in all cases, visual deficit in 66.6%, and diplopia in 76.9%. These results were confirmed by the review of the 127 cases reported in the literature. Conclusions: Despite its recent introduction, a significant number of spheno-orbital lesions treated with an eTOA are being reported. Its main advantages are favorable patient outcome and optimal cosmetic results, with minimal morbidity and quick recovery. This approach can be combined with other surgical routes or adjuvant therapies for complex tumors. However, it is a technically demanding procedure, requiring specific skills in endoscopic surgery, that should be reserved to dedicated centers

    Low appendicular muscle mass is correlated with femoral neck bone mineral density loss in postmenopausal women

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    <p>Abstract</p> <p>Background</p> <p>After menopause, rapid bone mass loss occurs in response to hypoestrogenism. Several studies suggest that muscle mass and bone mineral density (BMD) are positively associated in postmenopausal women. Therefore, it may be assumed that postmenopausal low appendicular muscle mass (aMM) can increase BMD loss in a short period of time.</p> <p>Objective</p> <p>The purpose of this study was to assess relationship of aMM with femoral neck BMD in postmenopausal women.</p> <p>Methods</p> <p>Prospective, controlled clinical Trial including 64 women aged 45-70 years, who had not had their last menstruation for at least one year. Subjects were divided into two groups: low aMM (n = 32), and normal aMM (n-32). Femoral neck BMD and muscle mass were measured by DXA at baseline and after twelve months. Pairwise and independent t tests were used for data analysis.</p> <p>Results</p> <p>Baseline weight, BMI and muscle mass (total and appendicular) significantly differ between groups (p < 0.05). After twelve months, femoral neck BMD was significantly lower in the group with low aMM, whereas no significant difference was observed in the group with normal aMM (p < 0.05).</p> <p>Conclusion</p> <p>In postmenopausal women, low appendicular muscle mass is associated negatively with femoral neck BMD in a short period of time.</p

    Hepatitis C virus NS5A is a direct substrate of casein kinase I-&#945;, a cellular kinase identified by inhibitor affinity chromatography using specific NS5A hyperphosphorylation inhibitors

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    The hepatitis C virus encodes a single polyprotein that is processed by host and viral proteases to yield at least 10 mature viral proteins. The nonstructural (NS) protein 5A is a phosphoprotein, and experimental data indicate that the phosphorylation state of NS5A is important for the outcome of viral RNA replication. We were able to identify kinase inhibitors that specifically inhibit the formation of the hyperphosphorylated form of NS5A (p58) in cells. These kinase inhibitors were used for inhibitor affinity chromatography in order to identify the cellular targets of these compounds. The kinases casein kinase I (CKI), p38 MAPK, CIT (Citron Rho-interacting kinase), GAK, JNK2, PKA, RSK1/2, and RIPK2 were identified in the high affinity binding fractions of two NS5A hyperphosphorylation inhibitors (NS5A-p58-i). Even though these kinases are targets of the NS5A-p58-i, the only kinase showing an effect on NS5A hyperphosphorylation was confirmed to be CKI-\u3b1. Although this finding does not exclude the possibility that other kinase(s) might be involved in basal or regulatory phosphorylation of NS5A, we show here that NS5A is a direct substrate of CKI-\u3b1. Moreover, in vitro phosphorylation of NS5A by CKI-\u3b1 resulted for the first time in the production of basal and hyperphosphorylated forms resembling those produced in cells. In vitro kinase reactions performed with NS5A peptides show that Ser-2204 is a preferred substrate residue for CKI-\u3b1 after pre-phosphorylation of Ser-2201

    ETV6::ABL1-Positive Myeloid Neoplasm: A Case of a Durable Response to Imatinib Mesylate without Additional or Previous Treatment

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    ETV6::ABL1 rearranged neoplasms are rare hematological diseases. To date, about 80 cases have been reported, including myeloid and lymphoid leukemias. The ETV6 gene codes for an ETS family transcription factor and several fusion partners have been described. When translocated, ETV6 causes the constitutive activation of the partner genes. Here, we report the case of a 54-year-old woman with a cryptic insertion of the 3′ region of ABL1 in the ETV6 gene. The patient was first diagnosed with idiopathic hypereosinophilic syndrome, according to the clinical history, conventional cytogenetics, standard molecular analyses and pathologist description. Next generation sequencing of diagnosis samples unexpectedly detected both ETV6::ABL1 type A and B fusion transcripts, which were then confirmed by FISH. The diagnosis was Myeloid/Lymphoid neoplasm with ETV6::ABL1 fusion, and the patient received imatinib mesylate treatment. In a follow-up after more than one year, the patient still maintained the molecular and complete hematological responses. This case highlights the importance of timely and proper diagnostics and prompt tyrosine kinase inhibitor treatment

    The Web will kill them all: new media, digital utopia, and political struggle in the Italian 5-Star Movement

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    This article examines the role of discourses about new media technology and the Web in the rise of the 5-Star Movement (Movimento 5 Stelle, or M5S) in Italy. Founded by comedian and activist Beppe Grillo and Web entrepreneur Gianrobe rto Casaleggio in 2009, this movement succeeded in becoming the second largest party at t he 2013 national elections in Italy. This article aims to discuss how elements of digital uto pia and Web-centric discourses have been inserted into the movement’s political message, and how the construction of the Web as a myth has shaped the movement’s discourse and political p ractice. The 5-Star Movement is compared and contrasted with other social and political move ments in Western countries which have displayed a similar emphasis on new media, such as the Occupy movement, the Indignados movement, and the Pirate Parties in Sweden and Germ any. By adopting and mutating cyber- utopian discourses from the so-called Californian i deology, the movement symbolically identifies itself with the Web. The traditional political esta blishment is associated with “old” media (television, radio, and the printed press), and rep resented as a “walking dead,” doomed to be superseded and buried by a Web-based direct democra cy

    Structural and biochemical characterization of the wild type PCSK9-EGF(AB) complex and natural familial hypercholesterolemia mutants

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    PCSK9 regulates low density lipoprotein receptor (LDLR) levels and consequently is a target for the prevention of atherosclerosis and coronary heart disease. Here we studied the interaction, of LDLR EGF(A/AB) repeats with PCSK9. We show that PCSK9 binds the EGF(AB) repeats in a pH-dependent manner. Although the PCSK9 C-terminal domain is not involved in LDLR binding, PCSK9 autocleavage is required. Moreover, we report the x-ray structure of the PCSK9 Delta C-EGF(AB) complex at neutral pH. Compared with the low pH PCSK9-EGF(A) structure, the new structure revealed rearrangement of the EGF( A) His-306 side chain and disruption of the salt bridge with PCSK9 Asp-374, thus suggesting the basis for enhanced interaction at low pH. In addition, the structure of PCSK9 Delta C bound to EGF(AB)(H306Y), a mutant associated with familial hypercholesterolemia (FH), reveals that the Tyr-306 side chain forms a hydrogen bond with PCSK9 Asp-374, thus mimicking His-306 in the low pH conformation. Consistently, Tyr-306 confers increased affinity for PCSK9. Importantly, we found that although the EGF(AB)(H306Y)-PCSK9 interaction is pH-independent, LDLRH306Y binds PCSK9 50-fold better at low pH, suggesting that factors other than His-306 contribute to the pH dependence of PCSK9-LDLR binding. Further, we determined the structures of EGF(AB) bound to PCSK9 Delta C containing the FH-associated D374Y and D374H mutations, revealing additional interactions with EGF(A) mediated by Tyr-374/His-374 and providing a rationale for their disease phenotypes. Finally, we report the inhibitory properties of EGF repeats in a cellular assay measuring LDL uptake

    Power training and postmenopausal hormone therapy affect transcriptional control of specific co-regulated gene clusters in skeletal muscle

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    At the moment, there is no clear molecular explanation for the steeper decline in muscle performance after menopause or the mechanisms of counteractive treatments. The goal of this genome-wide study was to identify the genes and gene clusters through which power training (PT) comprising jumping activities or estrogen containing hormone replacement therapy (HRT) may affect skeletal muscle properties after menopause. We used musculus vastus lateralis samples from early stage postmenopausal (50–57 years old) women participating in a yearlong randomized double-blind placebo-controlled trial with PT and HRT interventions. Using microarray platform with over 24,000 probes, we identified 665 differentially expressed genes. The hierarchical clustering method was used to assort the genes. Additionally, enrichment analysis of gene ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways was carried out to clarify whether assorted gene clusters are enriched with particular functional categories. The analysis revealed transcriptional regulation of 49 GO/KEGG categories. PT upregulated transcription in “response to contraction”—category revealing novel candidate genes for contraction-related regulation of muscle function while HRT upregulated gene expression related to functionality of mitochondria. Moreover, several functional categories tightly related to muscle energy metabolism, development, and function were affected regardless of the treatment. Our results emphasize that during the early stages of the postmenopause, muscle properties are under transcriptional modulation, which both PT and HRT partially counteract leading to preservation of muscle power and potentially reducing the risk for aging-related muscle weakness. More specifically, PT and HRT may function through improving energy metabolism, response to contraction as well as by preserving functionality of the mitochondria
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