Publications by authors named "Beyler A"

Background And Goals: The aims of the present study were to investigate the natural history of cirrhosis and to determine trends in the etiology of cirrhosis.

Methods: Between January 2001 and January 2018, a total of 1,341 patients had been diagnosed with cirrhosis and were included.

Results: A total of 898 cirrhotic patients, who were followed up for at least 6 months were included into the analysis.

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We present a method for obtaining the average single-molecule biexciton lifetime from an ensemble of chromophores in solution. We apply this analysis to a series of core/shell CdSe/CdS quantum dot heterostructures with increasing shell thickness and find that the lifetime of the biexciton increases with increasing shell thickness, consistent with a simultaneous measurement of biexciton quantum yield.

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Lead chalcogenide colloidal nanocrystals (NCs) are promising materials for solution processable optoelectronics. However, there is little agreement on the identity and character of PbS NC emission for different degrees of quantum confinement-a critical parameter for realizing applications for these nanocrystals. In this work, we combine ensemble and single NC spectroscopies to interrogate preparations of lead sulfide NCs.

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The optimization of photoluminescence spectral linewidths in semiconductor nanocrystal preparations involves minimizing both the homogeneous and inhomogeneous contributions to the ensemble spectrum. Although the inhomogeneous contribution can be controlled by eliminating interparticle inhomogeneities, far less is known about how to synthetically control the homogeneous, or single-nanocrystal, spectral linewidth. Here, we use solution photon-correlation Fourier spectroscopy (S-PCFS) to measure how the sample-averaged single-nanocrystal emission linewidth of CdSe core and core/shell nanocrystals change with systematic changes in the size of the cores and the thickness and composition of the shells.

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The brightness of nanoscale optical materials such as semiconductor nanocrystals is currently limited in high excitation flux applications by inefficient multiexciton fluorescence. We have devised a solution-phase photon correlation measurement that can conveniently and reliably measure the average biexciton-to-exciton quantum yield ratio of an entire sample without user selection bias. This technique can be used to investigate the multiexciton recombination dynamics of a broad scope of synthetically underdeveloped materials, including those with low exciton quantum yields and poor fluorescence stability.

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Prior to the advent of single-molecule fluorescence spectroscopy, many of the fundamental optical properties of colloidal semiconductor nanocrystal quantum dots were obscured by ensemble averaging over their inherent inhomogeneities. Single quantum dot spectroscopy has become a leading technique for the unambiguous determination of the governing excitonic physics of these quantum-confined systems. The analysis and interpretation of the timing and energies of photons emitted from individual nanocrystals have uncovered unexpected and fundamental electronic processes at the nanoscale.

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We measure the anomalous spectral diffusion of single colloidal quantum dots over eight temporal decades simultaneously by combining single-molecule spectroscopy and photon-correlation Fourier spectroscopy. Our technique distinguishes between discrete and continuous dynamics and directly reveals that the quasicontinuous spectral diffusion observed using conventional spectroscopy is composed of rapid, discrete spectral jumps. Despite their multiple time scales, these dynamics can be captured by a single mechanism whose parameters vary widely between dots and over time in individual dots.

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The spectral linewidth of an ensemble of fluorescent emitters is dictated by the combination of single-emitter linewidths and sample inhomogeneity. For semiconductor nanocrystals, efforts to tune ensemble linewidths for optical applications have focused primarily on eliminating sample inhomogeneities, because conventional single-molecule methods cannot reliably build accurate ensemble-level statistics for single-particle linewidths. Photon-correlation Fourier spectroscopy in solution (S-PCFS) offers a unique approach to investigating single-nanocrystal spectra with large sample statistics and high signal-to-noise ratios, without user selection bias and at fast timescales.

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Background/aims: The management of non-responders (NR) represents the most challenging of all aspects in the care of patients with chronic hepatitis C (CHC). The purpose of the study was to evaluate the efficacy of amantadine.

Methodology: Fourty- three patients with CHC who did not respond to prior combination therapy [IFNα-2a plus ribavirin for 48 weeks] were enrolled into the study.

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Background/aims: The aim of this study was to evaluate the efficacy of pegylated interferon (PEG-IFN) alfa-2b for short (one year) and long (two years) terms of treatment for chronic hepatitis D.

Methodology: Eighteen patients with chronic hepatitis D were administered PEG-IFN alfa-2b 1.5μg/kg twice weekly for 1 month, after which they were randomly assigned (2:1) to receive PEG-IFN alfa-2b 1.

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We describe Linearly Polarized Luminescent Solar Concentrators (LP-LSCs) to replace conventional, purely absorptive, linear polarizers in energy harvesting applications. As a proof of concept, we align 3-(2-Benzothiazolyl)-N,N-diethylumbelliferylamine (Coumarin 6) and 4- dicyanomethyl-6-dimethylaminostiryl-4H-pyran (DCM) dye molecules linearly in the plane of the substrate using a polymerizable liquid crystal host. We show that up to 38% of the photons polarized on the long axis of the dye molecules can be coupled to the edge of the device for an LP-LSC based on Coumarin 6 with an order parameter of 0.

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We describe Linearly Polarized Luminescent Solar Concentrators (LP-LSCs) to replace conventional, purely absorptive, linear polarizers in energy harvesting applications. As a proof of concept, we align 3-(2-Benzothiazolyl)-N,N-diethylumbelliferylamine (Coumarin 6) and 4-dicyanomethyl-6-dimethylaminostiryl-4H-pyran (DCM) dye molecules linearly in the plane of the substrate using a polymerizable liquid crystal host. We show that up to 38% of the photons polarized on the long axis of the dye molecules can be coupled to the edge of the device for an LP-LSC based on Coumarin 6 with an order parameter of 0.

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Background/aims: The pathogenesis of non-alcoholic steatohepatitis (NASH) is poorly understood. Hepatic iron and copper overload can directly cause lipid peroxidation and eventually hepatic damage. The aim of this study was to investigate the role of hepatic iron and copper accumulation in the development of NASH.

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Hepatic epithelioid hemangioendothelioma (HEH) is a rare vascular tumor of the liver of unknown etiology. Although HEH is usually characterized by a low grade malignancy and a good long-term prognosis, its growth can be progressive and lead to hepatic failure, extrahepatic metastasis and death. Several different antineoplastic agents have been proposed for cases of nonresectable HEH.

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Topterone, 17 alpha-propyltestosterone, was administered parenterally or topically to rats, rabbits or hamsters to determine its endocrine profile. Systemic administration demonstrated that topterone was both antiandrogenic and progestational. Topical application failed to elicit a systemic antiandrogenic response at 1 g/kg/day and only a minimal progestational response was seen at 32 mg/kg/day.

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Win 17,665 [topterone, (17 beta)-17-hydroxy-17-propylandrost-4-en-3-one] inhibited stimulation of flank organ development of castrated immature male hamsters by both testosterone and dihydrotestosterone, whereas progesterone inhibited the stimulation by only testosterone. Topical application of Win 17,665 on the flank organs of the male hamster did not cause any significant effect on testosterone metabolism of this tissue. In addition, there was no decrease in the lipogenic capacity of the flank organ.

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Ciprofibrate, a new orally effective hypolipidemic agent like clofibrate, suppressed tyloxapol-induced hypercholesterolemia in rats. Ciprofibrate at 10 mg/kg was effective. Clofibrate required a dosage of 180 mg/kg to suppress the tyloxapol effect.

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The blood levels, distribution and duration of action of ciprofibrate, an orally active hypolipidemic agent, was investigated in rats. Serum concentrations of 30 micrograms of ciprofibrate/ml are associated with significant reductions in both serum cholesterol and triglycerides in rats on a hyperlipidemic diet. Increasing the plasma concentrations of ciprofibrate to 69 micrograms/ml resulted in only a modest incremental reduction in serum lipids.

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Findings are given to show that ciprofibrate, a new orally active phenoxyisobutyrate, is significantly more hypolipidemic than is the reference clofibrate. In hyperlipidemic rats ciprofibrate suppresses the increase in blood lipids 33% at a daily dosage of 0.6--3 mg/kg.

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Topical application of the testosterone derivative 17alpha-propylandrost-4-en-17beta-ol-3-one (Win 17665) caused a dose-related regression of the hamster flank organ and guinea pig supracaudal gland in mature male animals. Histological examination confirmed that this action of Win 17665 was on the size of the hamster sebaceous glands and was reversible on cessation of treatment. Topical application of Win 17665 also counteracted flank organ stimulation by directly applied 5-alpha-dihydrotestosterone and 4-androstene-3,17-dione.

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