Measurements of strongly-anisotropic g-factors for spins in single quantum states

We have measured the full angular dependence, as a function of the direction of magnetic field, for the Zeeman splitting of individual energy states in copper nanoparticles. The g-factors for spin splitting are highly anisotropic, with angular variations as large as a factor of five. The angular dependence fits well to ellipsoids. Both the principal-axis directions and g-factor magnitudes vary between different energy levels within one nanoparticle. The variations agree quantitatively with random-matrix theory predictions which incorporate spin-orbit coupling.Comment: 4 pages, 3 figures, 2 in colo

Investigation of Mobility Limiting Mechanisms in Undoped Si/SiGe Heterostructures

We perform detailed magnetotransport studies on two-dimensional electron gases (2DEGs) formed in undoped Si/SiGe heterostructures in order to identify the electron mobility limiting mechanisms in this increasingly important materials system. By analyzing data from 26 wafers with different heterostructure growth profiles we observe a strong correlation between the background oxygen concentration in the Si quantum well and the maximum mobility. The highest quality wafer supports a 2DEG with a mobility of 160,000 cm^2/Vs at a density 2.17 x 10^11/cm^2 and exhibits a metal-to-insulator transition at a critical density 0.46 x 10^11/cm^2. We extract a valley splitting of approximately 150 microeV at a magnetic field of 1.8 T. These results provide evidence that undoped Si/SiGe heterostructures are suitable for the fabrication of few-electron quantum dots.Comment: Related papers at http://pettagroup.princeton.ed

Bacterial biofilms on biopolymeric sorbent supports for environmental bioremediation

Bioremediation encompasses a broad range of environmental biotechnology, which require multidisciplinary approaches through implementation of innovative tools to the natural biological process occurring in soil, water and air. Immobilization of hydrocarbon-degrading microorganisms on biodegradable sorbent supports significantly promotes bioremediation processes. Recently ecofriendly, low cost bioremediation devices based on polylactic acid (PLA) and polycaprolactone (PCL) membranes hosting a biodegrading bacterial biofilms were obtained[1]. This work investigates the higher effectiveness of immobilizing hydrocarbon-degrading bacteria compared to that of planktonic cells. Soil hydrocarbon (HC) degrading Actinobacteria Nocardia cyriacigeorgica strain SoB, Gordonia amicalis strain SoCg[2], and the marine hydrocarbonoclastic Alcanivorax borkumensis strain AU3-AA-7[3] were immobilized on PLA and PCL membranes and tested on hexadecane. The capacity of adhesion and proliferation of these biodegrading biofilms within the biopolymers were evaluated at various time points (5, 10, 15, and 30 incubation days) using scanning electron microscopy (SEM). The SEM images revealed that PLA and PCL nanofibers were nearly completely covered by a complex three-dimensional bacterial film for all tested strains. Quantification of total biomass (estimated as total dsDNA) confirmed biofilm growth up to 30 days of incubation. Crude oil biodegradation ability of biofilms-membranes systems, assessed by Gas Chromatography-FID analysis, demonstrated the removal of over 60% of the oil after 5 days of incubation, outperforming free-living bacteria by 24%. Viable plate counts showed that bacterial biofilms adsorbed on biopolymers were still viable after 30 days, indicating their potential for long-term applications

Understanding the dynamics of biological colloids to elucidate cataract formation towards the development of methodology for its early diagnosis

The eye lens is the most characteristic example of mammalian tissues exhibiting complex colloidal behaviour. In this paper we briefly describe how dynamics in colloidal suspensions can help addressing selected aspects of lens cataract which is ultimately related to the protein self-assembly under pathological conditions. Results from dynamic light scattering of eye lens homogenates over a wide protein concentration were analyzed and the various relaxation modes were identified in terms of collective and self-diffusion processes. Using this information as an input, the complex relaxation pattern of the intact lens nucleus was rationalized. The model of cold cataract - a phase separation effect of the lens cytoplasm with cooling - was used to simulate lens cataract at in vitro conditions in an effort to determine the parameters of the correlation functions that can be used as reliable indicators of the cataract onset. The applicability of dynamic light scattering as a non-invasive, early-diagnostic tool for ocular diseases is also demonstrated in the light of the findings of the present paper.Comment: Slightly different version from the published one 10 pages, 2 figure

Dynamic nuclear polarisation in biased quantum wires with spin-orbit interaction

We propose a new method for dynamic nuclear polarisation in a quasi one-dimensional quantum wire utilising the spin-orbit interaction, the hyperfine interaction, and a finite source-drain potential difference. In contrast with current methods, our scheme does not rely on external magnetic or optical sources which makes independent control of closely placed devices much more feasible. Using this method, a significant polarisation of a few per cent is possible in currently available InAs wires which may be detected by conductance measurements. This may prove useful for nuclear-magnetic-resonance studies in nanoscale systems as well as in spin-based devices where external magnetic and optical sources will not be suitable.Comment: 6 pages, published versio

A Novel Multi Scale Index for Exact and Approximate NKS Query Processing

Keyword based search in content rich multi-dimensional datasets encourages numerous novel applications and devices. In this paper, we consider objects that are labeled with Keywords and are implanted in a vector space. For these datasets, we consider questions that request the most impenetrable gatherings of focuses fulfilling a given arrangement of Keywords. We propose a novel strategy called ProMiSH (Projection and Multi Scale Hashing) that utilizations arbitrary projection and hash-based list structures, and accomplishes high versatility and speedup. We introduce a correct and an inexact variant of the algorithm

Comparison of Histochemical Stainings in Evaluation of Liver Fibrosis and Correlation with Transient Elastography in Chronic Hepatitis

Background and Aim. The best staining to evaluate liver fibrosis in liver hepatitis is still a debated topic. This study aimed to compare Masson's trichrome (MT), Sirius Red (SR), and orcein stainings in evaluating liver fibrosis in chronic HCV hepatitis (CHC) with semiquantitative and quantitative methods (Collagen Proportionate Area (CPA) by Digital Image Analysis (DIA)) and correlate them with transient elastography (TE). Methods. Liver stiffness evaluation of 111 consecutive patients with CHC was performed by TE. Semiquantitative staging by Metavir score system and CPA by DIA were assessed on liver biopsy stained with MT, SR, and orcein. Results. MT, SR, and orcein staining showed concordant results in 89.6% of cases in staging CHC, without significant difference in both semiquantitative and quantitative evaluations of fibrosis. TE values were concordant with orcein levels in 86.5% of the cases and with MT/RS in 77.5% (P < 0.001). No significant correlation between the grade of necroinflammatory activity and TE values was found. Conclusion. In CHC, SR/MT and orcein stainings are almost concordant and when discordant, orcein staining is better related to TE values than MT/RS. This suggests that elastic fibers play a more important role than reticular or collagenous ones in determining stiffness values in CHC

Efficacy of 8 weeks elbasvir/grazoprevir regimen for naïve-genotype 1b, HCV infected patients with or without glucose abnormalities: Results of the EGG18 study

Background and aim: Direct Acting Antivirals(DAAs) achieve the highest rate of sustained viral response(SVR) in patients with genotype-1b(G1b) Hepatitis C virus(HCV) infection. Reducing treatment duration can simplify the management and improve adherence of therapy. Patients and methods: The study evaluates the efficacy of 8 weeks of elbasvir/grazoprevir regimen in 75 treatment-naïve(TN), G1b patients with mild-moderate fibrosis(Liver Stiffness by Fibroscan® &lt;9.0&nbsp;kPa). Viral load(VL) has been evaluated by Roche TaqMan RT-PCR(LLOQ&lt;15 IU/ml). Results: Mean age was 61.0&nbsp;±&nbsp;14.2 years, 44% were male, mean LS by Fibroscan® was 6.1&nbsp;±&nbsp;1.8&nbsp;kPa. Twenty-eight patients(37.3%) had an HOMA&gt;2.5. Two patients were excluded from analysis(one dropped out and the other one had diagnosed genotype 2c at genotyping by sequencing performed after relapse). At 8 weeks(EOT), 71 out of 73 patients(97.3%) had undetectable HCV-RNA, while in two cases HCV-RNA was detectable but with VL&lt;15 IU/ml. Both of them achieved SVR. Two G1b patients relapsed at 12 weeks of follow-up, both with baseline VL&gt;800,000 IU/ml and HOMA score 1.3 and 3.8 respectively. Both had undetectable HCV VL at 4th week and at the EOT. Modified intention-to-treat SVR12 for G1b patients was 71/73(97.3%). Conclusion: In naïve, genotype-1b HCV-infected patients with mild/moderate liver fibrosis, short course of 8 weeks of EBR/GZR appears to achieve high efficacy regardless of features of insulin resistance

Obstructive Sleep Apnea Is Associated with Liver Damage and Atherosclerosis in Patients with Non-Alcoholic Fatty Liver Disease

We assessed whether obstructive sleep apnea (OSA) and nocturnal hypoxemia are associated with severity of liver fibrosis and carotid atherosclerosis in patients with biopsy-proven NAFLD and low prevalence of morbid obesity. Secondary aim was to explore the association of OSA and hypoxemia with NASH and severity of liver pathological changes