204 research outputs found

    Effects of Fe doping in La1/2Ca1/2MnO3

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    The effect of Fe doping in the Mn site on the magnetic, transport and structural properties of polycrystalline La1/2Ca1/2MnO3 was studied. Doping with low Fe concentration (< 10%) strongly affects electrical transport and magnetization. Long range charge order is disrupted even for the lowest doping level studied (~2%). For Fe concentration up to 5% a ferromagnetic state develops at low temperature with metallic like conduction and thermal hysteresis. In this range, the Curie temperature decreases monotonously as a function of Fe doping. Insulating behavior and a sudden depression of the ferromagnetic state is observed by further Fe doping.Comment: 2 pages, presented at ICM2000, to appear in JMM

    Giant enhancement in UV response of ZnO nanobelts by polymer surface-functionalization

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    High sensitivity photodetectors are of great significance in developing a new generation of optoelectronic devices in sensing, imaging, and other applications. In this Communication, highly sensitive UV detectors based on ZnO nanobelts (NBs) are achieved by polymer surface-functionalization. The UV-induced photoconductance in ZnO NBs increases by 5 orders of magnitude after functionalizing, using a polymer that exhibits large UV absorption. The huge increase in photoconductance is attributed to an electron-hole generation process as assisted by the energy states in the polymer. This study suggests that, by selecting polymers with different wavelengths of UV absorption, highly sensitive UV detectors with a large range of detection wavelengths can be fabricated using ZnO NBs

    Conceivable security risks and authentication techniques for smart devices

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    With the rapidly escalating use of smart devices and fraudulent transaction of users’ data from their devices, efficient and reliable techniques for authentication of the smart devices have become an obligatory issue. This paper reviews the security risks for mobile devices and studies several authentication techniques available for smart devices. The results from field studies enable a comparative evaluation of user-preferred authentication mechanisms and their opinions about reliability, biometric authentication and visual authentication techniques

    Does chronic oral anticoagulation reduce in-hospital mortality among COVID-19 older patients?

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    Background: Patients hospitalized with COVID-19 experienced an increased risk of venous thromboembolism. Aims: To evaluate the effect of chronic oral anticoagulation (OAC) therapy, both with vitamin K antagonists (VKAs) or direct oral anticoagulants (DOACs), on prognosis of COVID-19 older patients. Methods: Single-center prospective study conducted in the Emergency Department (ED) of a teaching hospital, referral center for COVID-19 in central Italy. We evaluated all the patients ≥ 65&nbsp;years, consecutively admitted to our ED for confirmed COVID-19. We compared the clinical outcome of those who were on chronic OAC at ED admission with those who did not, using a propensity score matched paired cohort of controls. The primary study endpoint was all-cause in-hospital death. Patients were matched for age, sex, clinical comorbidities, and clinical severity at presentation (based on NEWS ≥ 6). Study parameters were assessed for association to all-cause in-hospital death by a multivariate Cox regression analysis to identify independent risk factor for survival. Results: Although overall mortality was slightly higher for anticoagulated patients compared to controls (63.3% vs 43.5%, p = 0.012), the multivariate adjusted hazard ratio (HR) for death was not significant (HR = 1.56 [0.78–3.12]; p = 0.208). Both DOACs (HR 1.46 [0.73–2.92]; p = 0.283) and VKAs (HR 1.14 [0.48–2.73]; p = 0.761) alone did not affect overall survival in our cohort. Conclusions: Among older patients hospitalized for COVID-19, chronic OAC therapy was not associated with a reduced risk of in-hospital death. Moreover, our data suggest similar outcome both for patients on VKAs or in patients on DOACs

    The T.O.S.C.A. Project: Research, Education and Care

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    Despite recent and exponential improvements in diagnostic- therapeutic pathways, an existing “GAP” has been revealed between the “real world care” and the “optimal care” of patients with chronic heart failure (CHF). We present the T.O.S.CA. Project (Trattamento Ormonale dello Scompenso CArdiaco), an Italian multicenter initiative involving different health care professionals and services aiming to explore the CHF “metabolic pathophysiological model” and to improve the quality of care of HF patients through research and continuing medical education

    Do women â©ľ50 years of age need as much screening as women <50 years after they have had negative screening results?

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    To assess the adequacy of a routine screening to identify cervical intraepithelial neoplasia 2 or worse (CIN2+) in women over 50 years of age, a retrospective cohort was set in six Italian organised population-based screening programmes. In all, 287 330 women (1 714 550 person-years of observation, 1110 cases) screened at age 25–64, with at least two cytological screening tests, the first negative, were followed from their first negative smear until a biopsy proven CIN2+ lesion or their last negative smear. For women aged 25–49 and 50–64 years, crude and age-standardised detection rate (DR), cumulative risk (CR), adjusted hazard risk for number of previous negative screens, probability of false-positive CIN2+ after two or more smear tests were calculated. Detection rate is significantly lower over 50 years of age. Multivariable analysis shows a significant protective effect from four screening episodes (DR=0.70, 95% CI: 0.51–0.97); the effect of age ⩾50 is 0.29 (95% CI: 0.24–0.35). The CR of CIN2+ is at least eightfold higher in women <50 (CR=2.06, 95% CI: 1.88–2.23) after one previous negative test than in women ⩾50 years with four screens (CR=0.23, 95% CI: 0.00–0.46). Over 50 years of age, after four tests at least three false-positive cases are diagnosed for every true positive. Benefits arising from cytological screening is uncertain in well-screened older women

    Clinical Characteristics and Predictors of In-Hospital Mortality among Older Patients with Acute Heart Failure

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    Acute Heart Failure (AHF)-related hospitalizations and mortality are still high in western countries, especially among older patients. This study aimed to describe the clinical characteristics and predictors of in-hospital mortality of older patients hospitalized with AHF. We conducted a retrospective study including all consecutive patients ≥65 years who were admitted for AHF at a single academic medical center between 1 January 2008 and 31 December 2018. The primary outcome was all-cause, in-hospital mortality. We also analyzed deaths due to cardiovascular (CV) and non-CV causes and compared early in-hospital events. The study included 6930 patients, mean age 81 years, 51% females. The overall mortality rate was 13%. Patients ≥85 years had higher mortality and early death rate than younger patients. Infections were the most common condition precipitating AHF in our cohort, and pneumonia was the most frequent of these. About half of all hospital deaths were due to non-CV causes. After adjusting for confounding factors other than NYHA class at admission, infections were associated with an almost two-fold increased risk of mortality, HR 1.74, 95% CI 1.10–2.71 in patients 65–74 years (p = 0.014); HR 1.83, 95% CI 1.34–2.49 in patients 75–84 years (p = 0.001); HR 1.74, 95% CI 1.24–2.19 in patients ≥85 years (p = 0.001). In conclusion, among older patients with AHF, in-hospital mortality rates increased with increasing age, and infections were associated with an increased risk of in-hospital mortality. In contemporary patients with AHF, along with the treatment of the CV conditions, management should be focused on timely diagnosis and appropriate treatment of non-CV factors, especially pulmonary infections

    Frailty in Elderly Patients with Covid-19: A Narrative Review

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    Introduction: The SARS CoV-2 pandemic still generates a very high number of affected patients and a significant mortality rate. It is essential to establish objective criteria to stratify COVID-19 death risk. Frailty has been identified as a potential determinant of increased vulnerability in older adults affected by COVID-19, because it may suggest alterations of physical performance and functional autonomy. Methods: We have conducted a narrative review of the literature on the evidences regarding COVID-19 and the frailty condition. Thirteen observational studies were included. Conclusion: Data emerging from the studies indicate that older COVID-19 patients with a frailty condition have an increased risk of mortality compared with non-frail patients, and this association is independent of other clinical and demographic factors. A frailty evaluation is required to help clinicians to better stratify the overall risk of death for older patients with COVID-19
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