The use of ultrasound in clinical setting for children affected by NAFLD. is it safe and accurate?

Non-alcoholic fatty liver disease (NAFLD) has become over the last decade the most common form of chronic liver disease in children and adults. Thus, establishing the diagnosis of NAFLD is of utmost importance and represents a major challenge as the disease is generally silent and the current gold standard for diagnosis is an invasive liver biopsy, a procedure that is not suitable for screening purposes. Many non-invasive diagnostic tools have been evaluated so far. Recently the utility of ultrasonography for non-invasive diagnosis and estimation of hepatic steatosis has been demonstrated in a large prospective pediatric study

Low-loss amorphous silicon waveguides grown by PECVD on indium tin oxide

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All-optical modulation in a CMOS-compatible amorphous silicon-based device

Active silicon photonic devices, which dynamically control the flow of light, have received significant attention for their use in on-chip optical networks. High-speed active silicon photonic modulators and switches rely on the plasma dispersion effect, where a change in carrier concentration causes a variation in the refractive index. The necessary electron and hole concentration change can be introduced either by optical pumping, or by direct electrical injection and depletion. We demonstrate a fast photoinduced absorption effect in low loss hydrogenated amorphous silicon (a-Si:H) waveguides deposited at a temperature as low as 190°C. Significant modulation (M% ~90%) occurs with a 1 mm-long device. We attribute the enhanced modulation to the significantly larger free-carrier absorption effect of a-Si:H. The complementary metal-oxide semiconductor (CMOS) compatible technology of a-Si:H could be considered as a promising candidate to enable an easy back-end integration with standard microelectronics processes

Exchange Rates and Sovereign Risk

We empirically investigate the relation between currency excess returns and sovereign risk, as measured by credit default swap (CDS) spreads. An increase in a country’s CDS spread is accompanied by a contemporaneous depreciation of its exchange rate as well as an increase of its currency volatility and crash risk. The link between currency excess returns and sovereign risk is mainly driven by exposure to global sovereign risk shocks and also emerges in a predictive setting for currency risk premia. Sovereign risk forecasts excess returns to trading exchange rates, volatility and skewness, and is strongly priced in the cross-section of currencies. Moreover, we find that sovereign risk accounts for a large share of carry trade returns, and that carry and momentum strategies generate high (low) returns across countries with high (low) sovereign risk

Exchange rates and sovereign risk

An increase in a country's sovereign risk, as measured by credit default swap spreads, is accompanied by a contemporaneous depreciation of its currency and an increase of its volatility. The relation between currency excess returns and sovereign risk is mainly driven by default expectations (rather than distress risk premia) and exposure to global sovereign risk shocks, and also emerges in a predictive setting for currency risk premia. We show that a sovereign risk factor is priced in the cross-section of currency returns and that it is not subsumed by the carry factor.Christian Wagner acknowledges support from the Center for Financial Frictions (FRIC), grant no. DNRF10

Photometry of the Oort Cloud comet C/2009 P1(Garradd): pre-perihelion observations at 5.7 and 2.5 AU

The aim of this paper is to contribute to the characterization of the general properties of the Long Period Comets (LPCs) family, and in particular to report on the dust environment of comet C/2009 P1 (Garradd). The comet was observed at two epochs pre-perihelion, at ~6 AU and at ~2.5 AU: broad-band images have been used to investigate its coma morphology and properties and to model the dust production rate. Comet C/2009 P1 (Garradd) is one of the most active and “dust producing” LPCs ever observed, even at the large heliocentric distance rh~6 AU. Its coma presents a complex morphology, with subtle structures underlying the classical fan-shaped tail, and, at rh~2.5 AU, also jet-like structures and spiralling outflows. In the reference aperture of radius ρ=5°×104 km, the R-Afρ is 3693±156 cm and 6368±412 cm, in August 2010 (rh~6 AU) and July 2011 (rh~2.5 AU), respectively. The application of a first order photometric model, under realistic assumptions on grain geometric albedo, power-law dust size distribution, phase darkening function and grain dust outflow velocity, yielded a measure of the dust production rate for the two epochs of observation of Qd=7.27×102 kg/s and Qd=1.37×103 kg/s, respectively, for a reference outflow dust velocity of vsmall=25 m/s for small (0.1–10 µm) grains and vlarge=1 m/s for large (10 µm–1 cm) grains. These results suggest that comet Garradd is one of the most active minor bodies observed in recent years, highly contributing to the continuous replenishment of the Interplanetary Dust Complex also in the outer Solar System, and pose important constraints on the mechanism(s) driving the cometary activity at large heliocentric distances

Individualized hepatocellular carcinoma risk : the challenges for designing successful chemoprevention strategies

Hepatocellular carcinoma (HCC) develops in the context of environmental risk factors like chronic viral hepatitis, diabetes and alcohol exposure, often associated to an increased risk of cirrhosis. Antiviral treatments that are effective to counteract hepatitis B and C may also attenuate the risk of tumor development. However, since hepatitis B-related carcinogenesis is promoted independently of the onset of cirrhosis, such antiviral treatments as nucleo(t)side analogs can promote regression of cirrhosis, prevent clinical decompensation and variceal bleeding but not HCC. This means that in successfully treated patients with cirrhosis, HCC is often the consequence of their extended survival. In hepatitis C patients, a sustained virological response to interferon-based therapies can reduce the rate of HCC development, even in patients with cirrhosis who experience histological regression of their liver disease. Future therapies aimed at this endpoint in at risk populations should take into consideration pretreatment patient stratification for host, viral and environmental risk factors. In this context the recent discovery of single nucleotide polymorphisms involved in the immune system function and tumorigenesis, might permit enrollment of populations of patients enriched with HCC risk factors for targeted chemopreventive therapies. This could finally pave the way to personalized algorithms, as already seen in the diagnosis and treatment schemes for chemoprevention

Mercorio, A.; Della Corte, L.; De Angelis, M.C.; Buonfantino, C.; Ronsini, C.; Bifulco, G.; Giampaolino, P. Ovarian Drilling: Back to the Future. Medicina 2022, 58, 1002. https://doi.org/10.3390/ medicina58081002

Polycystic ovary syndrome (PCOS) is the leading cause of anovulatory infertility. The complex metabolic dysregulation at the base of this syndrome often renders infertility management challenging. Many pharmacological strategies have been applied for the induction of ovulation with a non-negligible rate of severe complications such as ovarian hyperstimulation syndrome and multiple pregnancies. Ovarian drilling (OD) is currently being adopted as a second-line treatment, to be performed in case of medical therapy. Laparoscopic ovarian drilling (LOD), the contemporary version of ovarian wedge resection, is considered effective for gonadotropins in terms of live birth rates, but without the risks of iatrogenic complications in gonadotropin therapy. Its endocrinal effects are longer lasting and, after the accomplishment of this procedure, ovarian responsiveness to successive ovulation induction agents is enhanced. Traditional LOD, however, is burdened by the potential risks of iatrogenic adhesions and decreased ovarian reserve and, therefore, should only be considered in selected cases. To overcome these limits, novel tailored and mini-invasive approaches, which are still waiting for wide acceptance, have been introduced, although their role is still not well-clarified and none of them have provided enough evidence in terms of efficacy and safety

Low-loss amorphous silicon waveguides grown by PECVD on indium tin oxide

Low-loss hydrogenated amorphous silicon (α-Si:H) waveguides were realized by plasma enhanced chemical vapour deposition (PECVD) on a transparent conductive oxide (TCO) layer which is intended to provide the buried contact for the application of an external bias in active devices, e.g. switches and modulators. In particular we propose a technological solution to overcome both the strong reduction in optical transmittance due to the very high extinction coefficient of metal contacts and, at the same time, the optical scattering induced by the texturization effect induced in α-Si:H films grown on TCO. The very high optical propagation losses were minimized by depositing a spin-on-glass (SOG) layer between the α-Si:H core-layer and the TCO bottom contact. In this case, propagation losses of 2.5 dB/cm at 1550 nm were measured. All the fabricated samples were optically characterized and the surface roughness was accurately measured using a mechanical profilometer. We observed that, for an α-Si:H core-layer directly deposited on the TCO contact, the surface roughness is of the order of 100 nm leading to totally opaque waveguides. The experimental performances have been compared to those obtained through calculations using an optical simulation package. The results are found to be in agreement with the experimental data