Nanostructured exchange coupled hard / soft composites: from the local magnetization profile to an extended 3D simple model

In nanocomposite magnetic materials the exchange coupling between phases plays a central role in the determination of the extrinsic magnetic properties of the material: coercive field, remanence magnetization. Exchange coupling is therefore of crucial importance in composite systems made of magnetically hard and soft grains or in partially crystallized media including nanosized crystallites in a soft matrix. It has been shown also to be a key point in the control of stratified hard / soft media coercive field in the research for optimized recording media. A signature of the exchange coupling due to the nanostructure is generally obtained on the magnetization curve $M(H)$ with a plateau characteristic of the domain wall compression at the hard/soft interface ending at the depinning of the wall inside the hard phase. This compression / depinning behavior is clearly evidenced through one dimensional description of the interface, which is rigorously possible only in stratified media. Starting from a local description of the hard/soft interface in a model for nanocomposite system we show that one can extend this kind of behavior for system of hard crystallites embedded in a soft matrix.Comment: 18 pages, 8 figures. To be published in the Journal of Magnetism and Magnetic Materials. (To be found at http://www.sciencedirect.com/science/journal/03048853

Long term nucleotide and nucleoside analogs treatment in chronic hepatitis B HBeAg negative genotype D patients and risk for hepatocellular carcinoma

Background and rationale of the study. Effect of Long-term nucleoside/nucleotide (NUC) on hepatocellular carcinoma (HCC) incidence in a population of HBeAg-negative genotype D patients has not been adequately studied in real-life cohorts. Our aim was to evaluate the impact of liver fibrosis and other variables on HCC incidence in this population of patients. Of 745 patients with chronic hepatitis B (CHB), 306 HBeAg-negative genotype D were selected and included in this study. All patients received treatment with NUC for at least 18 months. Patients with CHB or compensated cirrhosis were included. Patients with HCC diagnosed before or during the first 18 months of NUC therapy were excluded. Results. HCC was diagnosed in 2 CHB patients (1.0%) and 23 cirrhosis patients (20%) (OR = 24.41, 95% CI 5.40 < OR < 153.2; p < 0.0001). Multivariate analysis revealed that HCC risk was independently associated with age ≥ 60 years (OR = 6.45, 95% CI 1.22 to 34.0; p = 0.02) and liver cirrhosis (OR = 12.1, 95% CI 1.39 to 106.2; p = 0.02), but not with virological response (VR), and previous resistance to NUC, or rescue therapy. Multivariate analysis in cirrhosis patients revealed that only age ≥ 60 years was an independent risk factor associated with HCC (p = 0.003). Conclusions. Liver cirrhosis and age ≥ 60 years are the stronger risk factors for HCC in genotype D HBeAgnegative patients. Previous resistance to NUC in patients that achieved a VR after rescue therapy was not a predictive factor regarding HCC. VR does not appear to significantly reduce the overall incidence of HCC when a patient has already progressed to liver cirrhosis

Decline of Prevalence of Resistance Associated Substitutions to NS3 and NS5A inhibitors at DAA-failure in Hepatitis C Virus in Italy over the years 2015 to 2018

Background: A minority of patients fail to eliminate HCV and resistance-associated substitutions (RASs) are commonly detected at failure of interferon-free DAA regimens. Material and methods: Within the Italian network VIRONET-C, the prevalence of NS3/NS5A/NS5B RASs was retrospectively evaluated in patients who failed an EASL recommended DAA-regimen in 2015-2018. NS3, NS5A and NS5B Sanger sequencing was performed using homemade protocols. The geno2pheno system was used to infer HCV-genotype/subtype and predict drug resistance. The changes in the prevalence of RASs over time were evaluated using the chi-square test for trend, predictors of RASs at failure were analysed by logistic regression. Results: We included 386 real-life HCV pts failed to recommended DAA regimens: 92% (271/294) Italians, 75% (286/384) males, median age was 56 years (IQR 52-61); 106 (28%) were treatment-experienced: 91 (86%) with IFN-based treatments, 26 (25%) with DAA-based regimens. Metavir fibrosis stage was F4 in 76% (245/322), 65% (240/369) had clinical cirrhosis. Patients with HIV and HBV coinfection were 10% (33/317) and 8% (6/72), respectively. HCV genotype (G) was G1b in 122 pts (32%), G3a 103 (27%), G1a 97 (25%), G4d 30 (8%), G2c 19 (5%), G3h 5 (1.3%), G4a 4 (1%) and 1 (0.3%) each for G3g, G4n/o/v. DAA regimens were: LDV/SOF in 115 (30%), DCV/SOF in 103 (27%), 3D in 83 (21%), EBR/GRZ in 32 (8%), VEL/SOF in 29 (7%), GLE/PIB in 18 (5%) and 2D in 6 (2%); ribavirin was administered in 123 (32%). Antiviral treatment was completed by 352 pts (91%), while 34 (9%) discontinued prematurely. The NS5A fasta-sequence was available for all pts, NS5B for 361 (94%), NS3 for 365 (95%). The prevalence of any RASs was 87%, namely 78/135 (58%) in NS3, 303/359 (85%) in NS5A, 114/286 (40%) in NS5B (Tab 1). The prevalence of any RASs significantly declined from 2015 to 2018 (100%, 13/13 vs 81%, 101/125, p=0.01): NS5A RASs from 100%, 13/13 to 76%, 76/100 (p&lt;0.001), NS3 RASs from 88%, 7/8 to 44%, 28/63 (p=0.02), while NS5B RASs remained stable. Independent predictors of any RASs included liver cirrhosis/advanced fibrosis (AOR 3.72, CI 95% 1.51-9.17, p=0.004) and genotype (G2 vs G1a AOR 0.01, CI 95% 0.0-0.3, p&lt;0.001; G3 vs G1a AOR 0.22, CI 95% 0.05-0.98, p&lt;0.047; G4 vs G1a AOR 0.13, CI 95% 0.03-0.63, p&lt;0.011), with a modest effect scored for past treatment (AOR 3.45, CI 95% 1.00-11.92, p=0.05), after adjusting for DAA regimen and year of genotype. Notably, full activity was predicted for GLE/PIB in 75.9% of cases and for at least two components of VEL/SOF/VOX in 59% of cases and no case with full-resistance to either regimen was found (Tab 2). Conclusions: Despite decreasing prevalence over the years, RASs remain a common signature at virological failure of DAA treatment, particularly in patients with the highest grade of liver fibrosis. Their distribution may vary according to genotype, so the identification of RASs after failure could play a crucial role in optimizing retreatment strategies

Usefulness and limitations of transthoracic echocardiography in heart transplantation recipients

Transthoracic echocardiography is a primary non-invasive modality for investigation of heart transplant recipients. It is a versatile tool which provides comprehensive information about cardiac structure and function. Echocardiographic examinations can be easily performed at the bedside and serially repeated without any patient's discomfort. This review highlights the usefulness of Doppler echocardiography in the assessment of left ventricular and right ventricular systolic and diastolic function, of left ventricular mass, valvular heart disease, pulmonary arterial hypertension and pericardial effusion in heart transplant recipients. The main experiences performed by either standard Doppler echocardiography and new high-tech ultrasound technologies are summarised, pointing out advantages and limitations of the described techniques in diagnosing acute allograft rejection and cardiac graft vasculopathy. Despite the sustained efforts of echocardiographic technique in predicting the biopsy state, endocardial myocardial biopsies are still regarded as the gold standard for detection of acute allograft rejection. Conversely, stress echocardiography is able to identify accurately cardiac graft vasculopathy and has a recognised prognostic in this clinical setting. A normal stress-echo justifies postponement of invasive studies. Another use of transthoracic echocardiography is the monitorisation and the visualisation of the catheter during the performance of endomyocardial biopsy. Bedside stress echocardiography is even useful to select appropriately heart donors with brain death. The ultrasound monitoring is simple and effective for monitoring a safe performance of biopsy procedures

Characterization and modeling of the demagnetization processes in exchange-coupled SmCo5/Fe/SmCo5 trilayers

The demagnetization processes in epitaxially grown SmCo5 /Fe/SmCo5 trilayers have been analyzed in the framework of a one-dimensional micromagnetic model, exploiting the well-defined orientation of the easy magnetization axis present in both SmCo5 layers. The applied magnetic field is considered along easy, hard, and tilted directions. For the case of hard direction, the nucleation field equation and the analytical expression of the critical susceptibility are given. Due to the observed separate switching behavior of the two hard layers in the realized trilayers, the analysis also considers demagnetization processes in which the two hard layers have opposite magnetic polarization. Calculations based on the nominal values of the magnetic and geometric parameters for the ideal symmetric trilayer are only in qualitative agreement with the corresponding experimental curves. In order to explain the discrepancies, the influence of variations in the parameters has been deeply analyzed, as well as the effect of a distribution of tilting angles of the hard layers anisotropy axes. In addition, we have extended the model to treat the case of a real asymmetric trilayer, characterized by slightly different anisotropy properties of the two hard layers, and we have derived the corresponding nucleation field equation for the case of easy direction. This analysis shows that a better agreement between calculations and measurements concerning the reversible behavior of the trilayers can be achieved by slightly modifying the nominal soft layer thickness and by assigning different tilting angles to the hard layers. Moreover, it shows that the remaining discrepancies can be ascribed to imperfections, which cannot be considered in detail in the one-dimensional model

Traumatic potential of Recurrent Implantation Failure in Assisted Reproductive Technology paths for couples experiencing infertility

Heterosexual couples dealing with infertility can seek Assisted Reproductive Technology (ART) treatments to achieve pregnancy. Within these programs, infertile couples can experience Recurrent Implantation Failure (RIF), which is the failure to achieve a clinical pregnancy after three or more transfers of good-quality embryos into the uterus. RIF also refers to cases of biochemical pregnancy in which increased levels of Beta hCG hormone are detected without subsequent signs of clinical pregnancy.Although the psychological literature has shown that the repetition of ART attempts significantly correlates with negative psychological outcomes for men and women, to date there are no studies regarding the potentially traumatic features of RIF experiences.Hence, we provide an overview of the extant literature to highlight points of contact between the features of traumatic experiences and those of RIF and infertility, including the specific characteristics that make the population of infertile couples in ART programs potentially more vulnerable to trauma. This article aims to stimulate reflection in this area and emphasize the importance of expanding research to deepen our knowledge of the psychological processes involved in RIF conditions within ART treatments for infertile couples

Direct magnetocaloric characterization and simulation of thermomagnetic cycles

n experimental setup for the direct measurement of the magnetocaloric effect capable of simulating high frequency magnetothermal cycles on laboratory-scale samples is described. The study of the magnetocaloric properties of working materials under operative conditions is fundamental for the development of innovative devices. Frequency and time dependent characterization can provide essential information on intrinsic features such as magnetic field induced fatigue in materials undergoing first order magnetic phase transitions. A full characterization of the adiabatic temperature change performed for a sample of Gadolinium across its Curie transition shows the good agreement between our results and literature data and in-field differential scanning calorimetry.RST/Radiation, Science and TechnologyApplied Science

Market-Driven Management in Fashion and Luxury Industries

The Market-Driven Management requires that the continuous attention to customers is combined to constant and direct competition in all reference markets. The Market-Driven Management, in the specific context of companies competing in the fashion and luxury industries can be traced back to three main factors: a growing attention to brand equity; the reinforcement of the direct relationships with final consumers; the improvement of the information flow management system