Correlations of structural, magnetic, and dielectric properties of undoped and doped CaCu3Ti4O12

The present work reports synthesis, as well as a detailed and careful characterization of structural, magnetic, and dielectric properties of differently tempered undoped and doped CaCu3Ti4O12 (CCTO) ceramics. For this purpose, neutron and x-ray powder diffraction, SQUID measurements, and dielectric spectroscopy have been performed. Mn-, Fe-, and Ni-doped CCTO ceramics were investigated in great detail to document the influence of low-level doping with 3d metals on the antiferromagnetic structure and dielectric properties. In the light of possible magnetoelectric coupling in these doped ceramics, the dielectric measurements were also carried out in external magnetic fields up to 7 T, showing a minor but significant dependence of the dielectric constant on the applied magnetic field. Undoped CCTO is well-known for its colossal dielectric constant in a broad frequency and temperature range. With the present extended characterization of doped as well as undoped CCTO, we want to address the question why doping with only 1% Mn or 0.5% Fe decreases the room-temperature dielectric constant of CCTO by a factor of ~100 with a concomitant reduction of the conductivity, whereas 0.5% Ni doping changes the dielectric properties only slightly. In addition, diffraction experiments and magnetic investigations were undertaken to check for possible correlations of the magnitude of the colossal dielectric constants with structural details or with magnetic properties like the magnetic ordering, the Curie-Weiss temperatures, or the paramagnetic moment. It is revealed, that while the magnetic ordering temperature and the effective moment of all investigated CCTO ceramics are rather similar, there is a dramatic influence of doping and tempering time on the Curie-Weiss constant.Comment: 10 pages, 11 figure

Postoperative complications after pancreatoduodenectomy for malignancy: results from the Recurrence After Whipple’s (RAW) study

Background Pancreatoduodenectomy (PD) is associated with significant postoperative morbidity. Surgeons should have a sound understanding of the potential complications for consenting and benchmarking purposes. Furthermore, preoperative identification of high-risk patients can guide patient selection and potentially allow for targeted prehabilitation and/or individualized treatment regimens. Using a large multicentre cohort, this study aimed to calculate the incidence of all PD complications and identify risk factors. Method Data were extracted from the Recurrence After Whipple’s (RAW) study, a retrospective cohort study of PD outcomes (29 centres from 8 countries, 2012–2015). The incidence and severity of all complications was recorded and potential risk factors for morbidity, major morbidity (Clavien–Dindo grade > IIIa), postoperative pancreatic fistula (POPF), post-pancreatectomy haemorrhage (PPH) and 90-day mortality were investigated. Results Among the 1348 included patients, overall morbidity, major morbidity, POPF, PPH and perioperative death affected 53 per cent (n = 720), 17 per cent (n = 228), 8 per cent (n = 108), 6 per cent (n = 84) and 4 per cent (n = 53), respectively. Following multivariable tests, a high BMI (P = 0.007), an ASA grade > II (P II patients were at increased risk of major morbidity (P < 0.0001), and a raised BMI correlated with a greater risk of POPF (P = 0.001). Conclusion In this multicentre study of PD outcomes, an ASA grade > II was a risk factor for major morbidity and a high BMI was a risk factor for POPF. Patients who are preoperatively identified to be high risk may benefit from targeted prehabilitation or individualized treatment regimens

Interventions that increase use of adult immunization and cancer screening services: a meta-analysis.

Item does not contain fulltextPURPOSE: The relative effectiveness of the diverse approaches used to promote preventive care activities, such as cancer screening and adult immunization, is unknown. Despite many high-quality published studies, practices and policymakers attempting to improve preventive care have little definitive information on which to base decisions. Thus, we quantitatively assessed the relative effectiveness of previously studied approaches for improving adherence to adult immunization and cancer screening guidelines. DATA SOURCES: MEDLINE, the Cochrane Effective Practice and Organization of Care Review Group register, previous systematic reviews, and the Medicare Health Care Quality Improvement Project database. STUDY SELECTION: Controlled clinical trials that assessed interventions to increase use of immunizations for influenza and pneumococcal pneumonia and screening for colon, breast, and cervical cancer in adults. DATA EXTRACTION: Two reviewers independently extracted data on characteristics and outcomes from unmasked articles. Intervention components to increase use of services were classified as reminder, feedback, education, financial incentive, legislative action, organizational change, or mass media campaign. DATA SYNTHESIS: Of 552 abstracts and articles, 108 met the inclusion criteria. To assess the effect of intervention components, meta-regression models were developed for immunizations and each cancer screening service by using 81 studies with a usual care or control group. The most potent intervention types involved organizational change (the adjusted odds ratios for increased use of services from organizational change ranged from 2.47 to 17.6). Organizational change interventions included the use of separate clinics devoted to prevention, use of a planned care visit for prevention, or designation of nonphysician staff to do specific prevention activities. The next most effective intervention components were patient financial incentives (adjusted odds ratios, 1.82 to 3.42) and patient reminders (adjusted odds ratios, 1.74 to 2.75); the adjusted odds ratios ranged from 1.29 to 1.53 for patient education and from 1.10 to 1.76 for feedback. CONCLUSIONS: Rates of adult immunization and cancer screening are most likely to improve when a health care organization supports performance of these activities through organizational changes in staffing and clinical procedures. Involving patients in self-management through patient financial incentives and reminders is also likely to positively affect performance

Defect chemistry to trigger zirconia densification at low temperatures by Spark Plasma Sintering

In-depth control of reactivity and defects chemistry is shown to be mandatory to reach high density YSZ ceramics at sintering temperatures lower than 900°C. The combination of Cold Sintering Process (CSP) and Spark Plasma Sintering (SPS) has highlighted the role of transient chemistry on the densification of this material. More, optimised conditions were found for achieving densification of YSZ at 850°C in a one-step SPS process. In particular, the vacuum level in the SPS chamber is clearly shown to be a decisive parameter to obtain dense nanostructured YSZ tetragonal ceramics up to 95% below 900°C. The occurrence of oxygen vacancies has thus been addressed associating thermal analyses, X-ray photoelectron spectroscopy, Electron Paramagnetic Resonance, photoluminescence spectroscopy and impedance spectroscopy. Understanding defect chemistry mechanisms and their dependence on the process or combination of processes, is a lever towards high-quality YSZ nanostructured ceramics below 900°C

Loss of Caveolin-1 Gene Expression Accelerates the Development of Dysplastic Mammary Lesions in Tumor-Prone Transgenic Mice

Caveolin-1 is the principal structural component of caveolae microdomains, which represent a subcompartment of the plasma membrane. Several independent lines of evidence support the notion that caveolin-1 functions as a suppressor of cell transformation. For example, the human CAV-1 gene maps to a suspected tumor suppressor locus (D7S522/7q31.1) that is frequently deleted in a number of carcinomas, including breast cancers. In addition, up to 16% of human breast cancers harbor a dominant-negative mutation, P132L, in the CAV-1 gene. Despite these genetic associations, the tumor suppressor role of caveolin-1 still remains controversial. To directly assess the in vivo transformation suppressor activity of the caveolin-1 gene, we interbred Cav-1 (−/−) null mice with tumor-prone transgenic mice (MMTV-PyMT) that normally develop multifocal dysplastic lesions throughout the entire mammary tree. Herein, we show that loss of caveolin-1 gene expression dramatically accelerates the development of these multifocal dysplastic mammary lesions. At 3 wk of age, loss of caveolin-1 resulted in an approximately twofold increase in the number of lesions (foci per gland; 3.3 ± 1.0 vs. 7.0 ± 1.2) and an approximately five- to sixfold increase in the total area occupied by these lesions. Similar results were obtained at 4 wk of age. However, complete loss of caveolin-1 was required to accelerate the appearance of these dysplastic mammary lesions, because Cav-1 (+/−) heterozygous mice did not show any increases in foci development. We also show that loss of caveolin-1 increases the extent and the histological grade of these mammary lesions and facilitates the development of papillary projections in the mammary ducts. Finally, we demonstrate that cyclin D1 expression levels are dramatically elevated in Cav-1 (−/−) null mammary lesions, consistent with the accelerated appearance and growth of these dysplastic foci. This is the first in vivo demonstration that caveolin-1 can function as a transformation suppressor gene