Sampling for volatile organic compounds from an aquitard: A field evaluation of screen length, purging method, and sampling time

Purging method, sampling time, and screen length were compared to determine their impact on the collection of representative ground-water samples from monitoring wells sited in an aquitard contaminated with volatile organic compounds (VOC); Two well-purging methods--(1) pump to the bottom of the screened interval and (2) pump to the top of the screened interval--were evaluated on three monitoring wells with different screened intervals (0.75-m and 3.0-m screen lengths); Monitoring wells completed in an aquitard should be purged before collecting ground-water samples for VOC analysis. Samples collected 2-8 hours after purging were statistically similar and representative of the highest VOC concentrations attained in the well. VOC concentrations detected in a long-screen (3.0-m) well were significantly impacted by the purging method used. Variation in purging method did not significantly impact VOC concentrations in samples collected from the short-screen (0.75-m) Wells (Abstract shortened with permission of author.)

CMOS compatible athermal silicon microring resonators

Silicon photonics promises to alleviate the bandwidth bottleneck of modern day computing systems. But silicon photonic devices have the fundamental problem of being highly sensitive to ambient temperature fluctuations due to the high thermo-optic (TO) coefficient of silicon. Most of the approaches proposed to date to overcome this problem either require significant power consumption or incorporate materials which are not CMOS-compatible. Here we demonstrate a new class of optical devices which are passively temperature compensated, based on tailoring the optical mode confinement in silicon waveguides. We demonstrate the operation of a silicon photonic resonator over very wide temperature range of greater than 80 degrees. The fundamental principle behind this work can be extended to other photonic structures such as modulators, routers, switches and filters.Comment: 9 pages, 4 figure

Steatosis affects the performance of liver stiffness measurement for fibrosis assessment in patients with genotype 1 chronic hepatitis C

BACKGROUND & AIMS: In Chronic Hepatitis C (CHC), the influence of steatosis on liver stiffness measurement (LSM) is still debated. We assessed the impact of steatosis and its ultrasonographical sign - bright liver echo pattern (BLEP) - on LSM values and on transient elastography (TE) accuracy for the diagnosis of liver fibrosis, in a cohort of consecutive patients with Genotype 1 (G1) CHC. METHODS: Patients (n=618) were assessed by clinical, ultrasonographic and histological (Scheuer score) features. TE was performed using the M probe. RESULTS: Male gender (p=0.04), steatosis as continuous variable (p<0.001), severity of necroinflammation (p=0.02) and stage of fibrosis (p<0.001) were associated with LSM by multivariate linear regression analysis. Among patients within the same fibrosis stages (F0-F2 and F3-F4; F0-F3 and F4), mean LSM values, expressed in kPa, were significantly higher in subjects with moderate-severe steatosis (⩾20% at liver biopsy) compared with those without, as well as in patients with BLEP on US compared with their counterpart. In subjects without severe fibrosis (F0-F2) and without cirrhosis (F0-F3), a higher rate of false-positive LSM results was observed in patients with steatosis ⩾20% compared with those without (F0-F2: 35.3% vs. 17.9%; F0-F3: 38.9% vs. 16.6%), and in patients with BLEP on US (F0-F2: 28.0% vs. 18.3%; F0-F3: 29.7% vs. 17.8%) compared with their counterpart. CONCLUSIONS: In patients with G1 CHC, the presence of moderate-severe steatosis, detected by histology or by US, should always be taken into account in order to avoid overestimations of liver fibrosis assessed by TE

Status of CUORE Experiment and latest results from CUORE-0

Neutrinoless Double Beta Decay (0νββ) is a rare nuclear transition that if it occurs at all it will be very important for the exploration of the inverted hierarchy region of the neutrino mass pattern. The Cryogenic Underground Observatory for Rare Events (CUORE) is an experiment that aims to search for such a transition in 130Te together with other rare processes. In the present paper we will describe the basic features of CUORE Experiment, the status of the experiment as well as the latest results obtained from CUORE-0 detector, a smaller scale experiment constructed to test and demonstrate the expected performances of CUOR

Neurological Screening in Elderly Liver Transplantation Candidates: A Single Center Experience

Background: Cerebral small vessels disease (cSVD) is an age-related disorder and risk factor for stroke and cognitive/motor impairments. Neurological complications (NCs) are among the causes of adverse outcomes in older liver transplant recipients. This study sought to determine whether cSVD predicts acute NCs in over 65-year-old liver transplant patients. Methods: Data were collected, from a retrospective medical chart review, of 22 deceased donor liver transplant recipients aged 65 years or older with a pre-operative brain magnetic resonance imaging (MRI). We used the Fazekas score (0–3) as a quantitative measurement of the vascular lesion load seen in the MRI. We analyzed all post-operative acute NCs occurring during the hospital stay and any other non-NC. Results: cSVD was recognized in all patients. Neurological complications (NCs) occurred in 18.1% of patients with toxic-metabolic encephalopathy the most frequent diagnosis (13.64%). More severe cSVD was associated with seizures (p = 0.0362), longer hospital stay (p 0.0299), and disability (p 0.0134). In our elderly cohort, hepatic encephalopathy (HE) (p 0.0287) and ascites (p 0.0270) were predictors of NCs after liver transplantation. Ascites and/or variceal bleeding and severity of liver disease were associated with adverse post-operative outcomes. The small sample size limited the statistical analysis power. Conclusions: We present the preliminary data of a single-center retrospective study aimed at understanding the cSVD role on NCs and non-NCs after a liver transplantation in elderly patients. This would encourage a more appropriate multicenter prospective study that will definitely confirm if a neurological screening in old age liver transplant candidates is appropriate