812 research outputs found

    A simple limit for slope instability

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    Ross and Thomas have shown that subschemes can K-destabilise polarised varieties, yielding a notion known as slope (in)stability for varieties. Here we describe a special situation in which slope instability for varieties (for example of general type) corresponds to a slope instability type condition for certain bundles, making the computations almost trivial.Comment: 11 page

    Scalable Synthesis of Few-Layered 2D Tungsten Diselenide (2H-WSe2) Nanosheets Directly Grown on Tungsten (W) Foil Using Ambient-Pressure Chemical Vapor Deposition for Reversible Li-Ion Storage

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    We report a facile two-furnace APCVD synthesis of 2H-WSe2. A systematic study of the process parameters is performed to show the formation of the phase-pure material. Extensive characterization of the bulk and exfoliated material confirm that 2H-WSe2 is layered (i.e., 2D). X-ray diffraction (XRD) confirms the phase, while high-resolution scanning electron microscopy (HRSEM), high-resolution transmission electron microscopy (HRTEM), and atomic force microscopy (AFM) clarify the morphology of the material. Focused ion beam scanning electron microscopy (FIB-SEM) estimates the depth of the 2H-WSe2 formed on W foil to be around 5-8 ÎĽm, and Raman/UV-vis measurements prove the quality of the exfoliated 2H-WSe2. Studies on the redox processes of lithium-ion batteries (LiBs) show an increase in capacity up to 500 cycles. On prolonged cycling, the discharge capacity up to the 50th cycle at 250 mA/g of the material shows a stable value of 550 mAh/g. These observations indicate that exfoliated 2H-WSe2 has promising applications as an LiB electrode material

    Ethical, social and economic issues in familial breast cancer: a compilation of views from the EC biomed II demonstration project

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    ABSTRACT: Demand for clinical services for familial breast cancer is continuing to rise across Europe. Service provision is far from uniform and, in most centres, its evolution has been determined by local conditions, specifically by local research interests, rather than by central planning. However, in a number of countries there is evidence of progress towards co-ordinated development and audit of clinics providing risk assessment, counselling, screening and, in some cases, prophylactic intervention. Much important information should emerge from continued observation and comparative assessment of these developments. In most countries for which relevant data are available, there is a distinct bias towards higher social class among those who avail themselves of clinic facilities (in line with findings from many other health-promotion initiatives). This should be addressed when considering future organisation of clinical services. Molecular genetic studies designed to identify the underlying mutations responsible for familial breast cancer are not generally regarded as part of the clinical service and are funded through research grants (if at all). Economic considerations suggest that there is a case for keeping this policy under review. Familial cancers throw into sharp relief certain ethical and legal issues that have received much recent attention from government advisory bodies, patients ’ representatives, professional commentators and the popular media. Two are of particular importance; first, the right to gain access to medical records of relatives, in order to provide accurate risk assessment for a given family member, versus the right to privacy in respect of personal medical information and, second, the obligation (or otherwise) to inform family members of their risk status if they have not actively sought that knowledge. The legal position seems to vary from country to country and, in many cases, is unclear. In view of pressures to establish uniform approaches to medical confidentiality across the EC, it is important to evaluate the experience of participants in this Demonstration Programme and to apply the principle of “ non-malfeasance ” in formulating regu- lations that should govern future practice in this field. Data on economic aspects of familial breast cancer are remarkably sparse and outdated. As evidence accrues on the influence of screening and intervention programmes on morbidity and mortality, there is a strong case for evaluating the cost-effectiveness of different models of service provisi

    Design and testing of a textile EMG sensor for prosthetic control

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    Nowadays, Electromyography (EMG) signals generated by the amputee’s residual limbs are widely used for the control of myoelectric prostheses, usually with the aid of pattern-recognition algorithms. Since myoelectric prostheses are wearable medical devices, the sensors that integrate them should be appropriate for the users’ daily life, meeting the requirements of lightness, flexibility, greater motion identification, and skin adaptability. Therefore, this study aims to design and test an EMG sensor for prosthetic control, focusing on aspects such as adjustability, lightness, precise and constant signal acquisition; and replacing the conventional components of an EMG sensor with textile materials. The proposed sensor was made with Shieldex Technik-tex P130 + B conductive knitted fabric, with 99% pure silver plating. EMG data acquisition was performed twice on three volunteers: one with the textile sensor, and other with a commercial sensor used in prosthetic applications. Overall, the textile and the commercial sensor presented total average Signal-to-Noise Ratio (SNR) values of 10.24 ± 5.45 dB and 11.74 ± 8.64 dB, respectively. The authors consider that the obtained results are promising and leave room for further improvements in future work, such as designing strategies to deal with known sources of noise contamination and to increase the adhesion to the skin. In sum, the results presented in this paper indicate that, with the appropriate improvements, the proposed textile sensor may have the potential of being used for myoelectric prosthetic control, which can be a more ergonomic and accessible alternative to the sensors that are currently used for controlling these devices.This work is financed by Project “Deus ex Machina”, NORTE-01-0145-FEDER-000026, funded by CCDRN, through Sistema de Apoio à Investigação Científica e Tecnológica (Projetos Estruturados I&D&I) of Programa Operacional Regional do Norte, from Portugal 2020 and by Project UID/CTM/00264/2019 of 2C2T –Centro de Ciência e TecnologiaTêxtil, funded by National Founds through FCT/MCTES

    Experience of Remifentanil in Extremely Low-birth-weight Babies Undergoing Laparotomy

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    Premature babies experience pain and require adequate analgesia for any painful procedure. Fentanyl and morphine resulted in safe and effective anesthesia in the past; however, their pharmacokinetics may be impaired in preterm babies with multiorgan failure. Remifentanil, despite the absence of available pharmacokinetic data in preterm infants and few reports in newborns, demonstrated its advantages in children undergoing either major surgery or minor painful procedures and has been shown to be useful even in neonates, because its elimination is independent of organ function. We report two cases of babies born at 26 weeks’ and 27 weeks’ gestation, weighing 580g and 400g, respectively, undergoing laparotomy for necrotizing enterocolitis. Both received midazolam bolus and remifentanil infusion at high doses. This technique seems to be an advantageous alternative even in extremely low-birth-weight prematures. Furthermore, it becomes a technique of choice in these babies because the available ventilators are often not equipped with halogenated vaporizers. Particularly in intensive care, where there are no scavenger systems, it could allow to operate without moving out the preterm babies and avoiding stress and hypothermia

    ICOS-Fc as innovative immunomodulatory approach to counteract inflammation and organ injury in sepsis

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    Inducible T cell co-stimulator (ICOS), an immune checkpoint protein expressed on activated T cells and its unique ligand, ICOSL, which is expressed on antigen-presenting cells and non-hematopoietic cells, have been extensively investigated in the immune response. Recent findings showed that a soluble recombinant form of ICOS (ICOS-Fc) can act as an innovative immunomodulatory drug as both antagonist of ICOS and agonist of ICOSL, modulating cytokine release and cell migration to inflamed tissues. Although the ICOS-ICOSL pathway has been poorly investigated in the septic context, a few studies have reported that septic patients have reduced ICOS expression in whole blood and increased serum levels of osteopontin (OPN), that is another ligand of ICOSL. Thus, we investigated the pathological role of the ICOS-ICOSL axis in the context of sepsis and the potential protective effects of its immunomodulation by administering ICOS-Fc in a murine model of sepsis. Polymicrobial sepsis was induced by cecal ligation and puncture (CLP) in five-month-old male wild-type (WT) C57BL/6, ICOS(-/-), ICOSL(-/-) and OPN(-/-) mice. One hour after the surgical procedure, either CLP or Sham (control) mice were randomly assigned to receive once ICOS-Fc, (F119S)ICOS-Fc, a mutated form uncapable to bind ICOSL, or vehicle intravenously. Organs and plasma were collected 24 h after surgery for analyses. When compared to Sham mice, WT mice that underwent CLP developed within 24 h a higher clinical severity score, a reduced body temperature, an increase in plasma cytokines (TNF-α, IL-1β, IL-6, IFN-γ and IL-10), liver injury (AST and ALT) and kidney (creatinine and urea) dysfunction. Administration of ICOS-Fc to WT CLP mice reduced all of these abnormalities caused by sepsis. Similar beneficial effects were not seen in CLP-mice treated with (F119S)ICOS-Fc. Treatment of CLP-mice with ICOS-Fc also attenuated the sepsis-induced local activation of FAK, P38 MAPK and NLRP3 inflammasome. ICOS-Fc seemed to act at both sides of the ICOS-ICOSL interaction, as the protective effect was lost in septic knockout mice for the ICOS or ICOSL genes, whereas it was maintained in OPN knockout mice. Collectively, our data show the beneficial effects of pharmacological modulation of the ICOS-ICOSL pathway in counteracting the sepsis-induced inflammation and organ dysfunction

    Low expression of bcl-2 in Brca1-associated breast cancers

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    Little data are available concerning the molecular mechanisms of action of Brca1 and Brca2 in breast oncogenesis. Recent experimental results suggest that Brca1 plays a role in the regulation of apoptosis. In order to determine whether the analysis of human tumours would provide data supporting this hypothesis, we have assessed the expression of the antiapoptotic bcl-2 and of the proapoptotic p53 genes in Brca1- and Brca2-associated breast carcinomas. The levels of expression of these genes were compared to those observed in controls and to the mitotic and the apoptotic indexes. Our series were composed of 16 cases of breast carcinoma in women with a germline Brca1 gene mutation, and of four cases with Brca2 mutation. A group of 39 patients aged under 36 years and for whom the search for Brca1 gene mutations was negative, and a group of 36 cases of sporadic cancers without data on their Brca status were used as controls. Immunohistochemistry was used to detect p53 and bcl-2 gene products. Mitotic and apoptotic indexes were higher in Brca1-associated tumours than in controls. No significant difference in p53 immunostaining was observed between the four groups of patients. In contrast, the rate of bcl-2-positive tumours was lower (31%) in Brca1-carcinomas than in carcinomas without Brca1 mutation (90%) (P< 10–3). A strong Bcl-2 expression was found in the four cases of Brca2-associated carcinomas. No significant correlation was observed between p53 and Bcl-2 immunostainings, either in cases or in controls. The association between Brca1 status and Bcl-2 expression remained significant after adjustment for the oestrogen receptor status. Our study shows that a low expression of bcl-2 characterises most Brca1-associated breast carcinomas, a biological trait which seems not to be shared by Brca2-associated tumours nor to be related to oestrogen receptor and/or p53 status.bcl-2 might thus be one of the target genes involved in the oncogenesis related to Brca1 and its down-regulation may account for the increased apoptosis and the high proliferative rate observed in Brca1-associated carcinomas. © 2000 Cancer Research Campaig
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