91 research outputs found
A New Model to Derive the Transport Parameters in CZT Detectors with a Liner Decreasing Internal Electric Field
Charge collection efficiency and material transport properties in CdTe and CZT planar devices for X and gamma ray detection are commonly determined by means of the Hecht equation, under the limiting approximation of a uniform internal electric field. As an alternative, the Manys theory is helpful when surface recombination velocity of carriers has to be taken into account. Experiments carried out on planar detectors have shown a non constant, linearly decreasing profiles of the internal electric field and, in several cases, the electric field does not decrease down to zero but to a fixed value different and afterwards it result to be constant. A similar non-uniform electric field could be also expected when a high radiation flux hits the surface near the detector contacts. This fact could explains as photoconductivity measurements on these kinds of devices are often not so easy described by means of the Hecht theory. Last of all, the use of the Hecht or Manys equations to fit photoconductivity curves could lead to wrong conclusionsin the determination of μτ product. Starting from the Ramo-Shockley theorem, the authors calculate a new relation between charge collection efficiency and applied bias in the case of an electric field decreasing linearly along the detector thickness, being satisfied all the other Hecht hypotheses. The new functional dependence of charge collection efficiency on applied bias contains the slope of the electric field as a parameter and provides for the Hecht model as the special solution when the electric field is uniform. Moreover this model allows to fit with a very good accuracy experimental results on several our CZT detectors. The authors believe that this shape of field should be widespread in presence of diffused spatial charge and think that this model could be an important instrument for interpreting the data arising from pulsed photocurrent measures not only for CdTe and CZT detectors but also for other materials
The impact of reproductive life on breast cancer risk in women with family history or BRCA mutation
Reproductive history and exogenous hormonal exposures are acknowledged risk factors for breast cancer in the general population. In women at increased breast cancer risk for genetic predisposition or positive family history, data regarding these risk factors are limited or con icting, and recommendations for these categories are unclear. We evaluated the characteristics of reproductive life in 2522 women at increased genetic or familial breast cancer risk attending our Family Cancer Center. Breast cancers in BRCA mutation carriers were more likely to be hormone receptor negative, diagnosed at 35 years or before and multiple during the lifetime than tumors in women at increased familial risk, while the distribution of invasive cancers and HER2 positive tumors was similar in the different risk groups. At least one full- term pregnancy (HR 0.27; 95% CI 0.12\u20130.58; p = 0.001), breastfeeding either less (HR 0.24; 95% CI 0.09\u20130.66; p = 0.005) or more (HR 0.25; 95% IC 0.08\u20130.82; p = 0.022) than one year and late age at menopause (HR 0.10; 95% CI 0.01\u20130.82; p = 0.033) showed to be protective factors in BRCA mutation carriers, while in women at increased familial risk early age at rst full-term pregnancy (HR 0.62; 95% IC 0.38\u20130.99; p = 0.048) and late menarche (HR 0.61; 95% CI 0.42\u20130.85; p = 0.004) showed to be the main protective factors. Finally, for the entire population, combined hormonal contraceptives demonstrated to do not increase breast cancer risk. The results of our study suggest that women at high familial risk and mutation carries develop tumors with different clinical-pathological characteristics and, consequently, are in uenced by different protective and risk factors
Topographical and compositional gradient tubular scaffold for bone to tendon interface regeneration
The enthesis is an extremely specific region, localized at the tendon–bone interface (TBI) and made of a hybrid connection of fibrocartilage with minerals. The direct type of enthesis tissue is commonly subjected to full laceration, due to the stiffness gradient between the soft tissues and hard bone, and this often reoccurs after surgical reconstruction. For this purpose, the present work aimed to design and develop a tubular scaffold based on pullulan (PU) and chitosan (CH) and intended to enhance enthesis repair. The scaffold was designed with a topographical gradient of nanofibers, from random to aligned, and hydroxyapatite (HAP) nanoparticles along the tubular length. In particular, one part of the tubular scaffold was characterized by a structure similar to bone hard tissue, with a random mineralized fiber arrangement; while the other part was characterized by aligned fibers, without HAP doping. The tubular shape of the scaffold was also designed to be extemporarily loaded with chondroitin sulfate (CS), a glycosaminoglycan effective in wound healing, before the surgery. Micro CT analysis revealed that the scaffold was characterized by a continuous gradient, without interruptions from one end to the other. The gradient of the fiber arrangement was observed using SEM analysis, and it was still possible to observe the gradient when the scaffold had been hydrated for 6 days. In vitro studies demonstrated that human adipose stem cells (hASC) were able to grow and differentiate onto the scaffold, expressing the typical ECM production for tendon in the aligned zone, or bone tissue in the random mineralized part. CS resulted in a synergistic effect, favoring cell adhesion/proliferation on the scaffold surface. These results suggest that this tubular scaffold loaded with CS could be a powerful tool to support enthesis repair upon surgery.Horizon 2020 Research and Innovation Programme under Grant Agreement No. 81460
Invasive meningococcal disease in three siblings with hereditary deficiency of the 8th component of complement: Evidence for the importance of an early diagnosis
Deficiency of the eighth component of complement (C8) is a very rare primary immunodeficiency, associated with invasive, recurrent infections mainly caused by Neisseria species. We report functional and immunochemical C8 deficiency diagnosed in three Albanian siblings who presented with severe meningococcal infections at the age of 15 years, 4 years and 17 months, respectively. The youngest suffered serious complications (necrosis of fingers and toes requiring amputation).
METHODS:
Functional activity of the classical, alternative and mannose-binding lectin complement pathways was measured in serum from the 3 siblings and their parents (37-year-old woman and 42-year-old man). Forty healthy subjects (20 males and 20 females aged 4-38 years) served as normal controls. Serum complement factors were measured by haemolytic assays and immunoblotting. Sequence DNA analysis of the C8B gene was performed.
RESULTS:
Analyses of the three complement pathways revealed no haemolytic activity and also absence of C8beta in serum samples from all three siblings. The genetic analysis showed that the three siblings were homozygous for the p.Arg428* mutation in the C8B gene on chromosome 1p32 (MIM 120960). The parents were heterozygous for the mutation and presented normal complement activities. A 2-year follow-up revealed no further infective episodes in the siblings after antibiotic prophylaxis and meningococcal vaccination.
CONCLUSIONS:
Complement deficiencies are rare and their occurrence is often underestimated. In presence of invasive meningococcal infection, we highlight the importance of complement screening in patients and their relatives in order to discover any genetic defects which would render necessary prophylaxis to prevent recurrent infections and severe complications
Effects of Albumin Treatment on Systemic and Portal Hemodynamics and Systemic Inflammation in Patients With Decompensated Cirrhosis
BACKGROUND & AIMS: We investigated the effect of albumin treatment (20% solution) on hypoalbuminemia, cardiocirculatory dysfunction, portal hypertension, and systemic inflammation in patients with decompensated cirrhosis with and without bacterial infections. METHODS: We performed a prospective study to assess the effects of long-term (12 weeks) treatment with low doses (1 g/kg body weight every 2 weeks) and high doses (1.5 g/kg every week) of albumin on serum albumin, plasma renin, cardiocirculatory function, portal pressure, and plasma levels of cytokines, collecting data from 18 patients without bacterial infections (the Pilot-PRECIOSA study). We also assessed the effect of short-term (1 week) treatment with antibiotics alone vs the combination of albumin plus antibiotics (1.5 g/kg on day 1 and 1 g/kg on day 3) on plasma levels of cytokines in biobanked samples from 78 patients with bacterial infections included in a randomized controlled trial (INFECIR-2 study). RESULTS: Circulatory dysfunction and systemic inflammation were extremely unstable in many patients included in the Pilot-PRECIOSA study; these patients had intense and reversible peaks in plasma levels of renin and interleukin 6. Long-term high-dose albumin, but not low-dose albumin, was associated with normalization of serum level of albumin, improved stability of the circulation and left ventricular function, and reduced plasma levels of cytokines (interleukin 6, granulocyte colony-stimulating factor, interleukin 1 receptor antagonist, and vascular endothelial growth factor) without significant changes in portal pressure. The immune-modulatory effects of albumin observed in the Pilot-PRECIOSA study were confirmed in the INFECIR-2 study. In this study, patients given albumin had significant reductions in plasma levels of cytokines. CONCLUSIONS: In an analysis of data from 2 trials (Pilot-PRECIOSA study and INFECIR-2 study), we found that albumin treatment reduced systemic inflammation and cardiocirculatory dysfunction in patients with decompensated cirrhosis. These effects might be responsible for the beneficial effects of albumin therapy on outcomes of patients with decompensated cirrhosis. ClinicalTrials.gov, Numbers: NCT00968695 and NCT03451292
Prolonged higher dose methylprednisolone vs. conventional dexamethasone in COVID-19 pneumonia: a randomised controlled trial (MEDEAS)
Dysregulated systemic inflammation is the primary driver of mortality in severe COVID-19 pneumonia. Current guidelines favor a 7-10-day course of any glucocorticoid equivalent to dexamethasone 6 mg·day-1. A comparative RCT with a higher dose and a longer duration of intervention was lacking
Life history and temporal distribution of Orchestia sp. cf. cavimana (Amphipoda, Talitridae) on a lake shore in central Italy
The life history of the amphipod Orchestia sp. cf. cavimana (Heller, 1865) was studied throughout the course of a year with monthly samplings and the use of pitfall traps along the shores of Lake Albano in central Italy. The data thus obtained showed two peaks in abundance (the first in June and the second in October) and a minimum capture frequency in February. Egg-bearing females were recorded in spring and late summer, whilst recruitment occurred from spring to autumn, with maximum in June and October. The data collected also indicated the presence of a positive correlation between the abundance of talitrids and both temperature and sediment moisture. Morphological analysis enabled the identification of four different cohorts (with a lifespan of the species of approximately 12-15 months) all four of which remained distinguishable throughout the course of the year. It, moreover, enabled sex determination in individuals of 5 or more millimetres. The subsequent distribution indicated that, when significant, the sex ratio was female biased and that maximum size was greater in males. In particular, maximum sizes were recorded in spring for both males and females and were of 17.5 and 13.0 mm, respectively. Furthermore, the total body length recorded for egg-bearing females was positively correlated with the number of eggs in their brood pouch. (C) 2009 Elsevier GmbH. All rights reserved
Life history of the talitrid amphipod Macarorchestia remyi (Schellenberg, 1950) on a Tyrrhenian sandy beach, Italy
In this study, we analysed the life cycle and some aspects of the reproductive biology of the talitrid amphipod Macarorchestia remyi (Schellenberg, 1950) on a sandy beach in central Italy (Tyrrhenian Sea). The species is strongly associated with rotting wood carried by the sea. The animals were sampled once a month by hand over 1 year (May 2006-April 2007) and a total of 3,484 individuals were collected. Results showed the occurrence of intersexes in addition to males and females (n = 268) and a sex ratio always in favour of females. Breeding peaked twice during the year and the number of eggs in the ventral brood chamber ranged from 3 to 19. Linear regression analysis showed a positive correlation between total length of ovigerous females and the number of eggs they carried. The mean length of both mature males and mature females was 6 mm, while the maximum length was 13 mm. The presence of two cohorts during the year was also identified. Our results suggest that, despite the ephemeral habitats where the species lives, the population is stable over time and its life cycle does not differ in relation to other talitrid species that live on beaches
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