Hepatic Blood Flow in Hepatic Bilharzial Fibrosis Before and After Surgery

This review confirms that in hepatic bilharziaI fibrosis the hepatic blood flow (HBF) values obtained indirectly by the depuration constant of IlII rose bengal are within the limits of normality. The variations of the HBF before and after splenectomy and splenorenal shunt were also studied.S. Afr. Med. J., 48, 1312 (1974)

Beta-blockers to prevent gastroesophageal varices in patients with cirrhosis.

BACKGROUND: Nonselective beta-adrenergic blockers decrease portal pressure and prevent variceal hemorrhage. Their effectiveness in preventing varices is unknown. METHODS: We randomly assigned 213 patients with cirrhosis and portal hypertension (minimal hepatic venous pressure gradient [HVPG] of 6 mm Hg) to receive timolol, a nonselective beta-blocker (108 patients), or placebo (105 patients). The primary end point was the development of gastroesophageal varices or variceal hemorrhage. Endoscopy and HVPG measurements were repeated yearly. RESULTS: During a median follow-up of 54.9 months, the rate of the primary end point did not differ significantly between the timolol group and the placebo group (39 percent and 40 percent, respectively; P=0.89), nor were there significant differences in the rates of ascites, encephalopathy, liver transplantation, or death. Serious adverse events were more common among patients in the timolol group than among those in the placebo group (18 percent vs. 6 percent, P=0.006). Varices developed less frequently among patients with a baseline HVPG of less than 10 mm Hg and among those in whom the HVPG decreased by more than 10 percent at one year and more frequently among those in whom the HVPG increased by more than 10 percent at one year. CONCLUSIONS: Nonselective beta-blockers are ineffective in preventing varices in unselected patients with cirrhosis and portal hypertension and are associated with an increased number of adverse events. (ClinicalTrials.gov number, NCT00006398.

Statistical Signatures of Photon Localization

The realization that electron localization in disordered systems (Anderson localization) is ultimately a wave phenomenon has led to the suggestion that photons could be similarly localized by disorder. This conjecture attracted wide interest because the differences between photons and electrons - in their interactions, spin statistics, and methods of injection and detection - may open a new realm of optical and microwave phenomena, and allow a detailed study of the Anderson localization transition undisturbed by the Coulomb interaction. To date, claims of three-dimensional photon localization have been based on observations of the exponential decay of the electromagnetic wave as it propagates through the disordered medium. But these reports have come under close scrutiny because of the possibility that the decay observed may be due to residual absorption, and because absorption itself may suppress localization. Here we show that the extent of photon localization can be determined by a different approach - measurement of the relative size of fluctuations of certain transmission quantities. The variance of relative fluctuations accurately reflects the extent of localization, even in the presence of absorption. Using this approach, we demonstrate photon localization in both weakly and strongly scattering quasi-one-dimensional dielectric samples and in periodic metallic wire meshes containing metallic scatterers, while ruling it out in three-dimensional mixtures of aluminum spheres.Comment: 5 pages, including 4 figure

Photonic crystals with controlled disorder

Photonic crystals are extremely sensitive to structural disorder even to the point of completely losing their functionalities. While, on one side, this can be detrimental for applications in traditional optical devices, on the other side, it gives also rise to very interesting new physics and maybe even new applications. We propose a route to introduce disorder in photonic crystals in a controlled way by creating a certain percentage of vacancies in the lattice. We show how the method works and what type of materials can be obtained this way. Also, we use this system to probe the role of disorder on the resulting transport properties from various points of view, including measurements of the transport and scattering mean free path and the diffusion constant

Morphological image analysis for classification of gastrointestinal tissues using optical coherence tomography

Computer-aided diagnosis of ophthalmic diseases using optical coherence tomography (OCT) relies on the extraction of thickness and size measures from the OCT images, but such defined layers are usually not observed in emerging OCT applications aimed at "optical biopsy" such as pulmonology or gastroenterology. Mathematical methods such as Principal Component Analysis (PCA) or textural analyses including both spatial textural analysis derived from the two-dimensional discrete Fourier transform (DFT) and statistical texture analysis obtained independently from center-symmetric auto-correlation (CSAC) and spatial grey-level dependency matrices (SGLDM), as well as, quantitative measurements of the attenuation coefficient have been previously proposed to overcome this problem. We recently proposed an alternative approach consisting of a region segmentation according to the intensity variation along the vertical axis and a pure statistical technology for feature quantification. OCT images were first segmented in the axial direction in an automated manner according to intensity. Afterwards, a morphological analysis of the segmented OCT images was employed for quantifying the features that served for tissue classification. In this study, a PCA processing of the extracted features is accomplished to combine their discriminative power in a lower number of dimensions. Ready discrimination of gastrointestinal surgical specimens is attained demonstrating that the approach further surpasses the algorithms previously reported and is feasible for tissue classification in the clinical setting

A non-chiral lithium aluminate reagent for the determination of enantiomeric excess of chiral alcohols

Here we illustrate a new method for the rapid determination of ee’s of chiral alcohols using the thermally-stable, non-chiral lithium aluminate reagent [EtAl(6-Me-2-py)$_3$Li] (1). $\textit{In situ}$ reaction of the alcohols with 1 produces robust dimers in solution, present as diastereomeric pairs ($\textit{SS/RR}$ and $\textit{RS}$) with distinct resonances in their $^1$H and $^7$Li NMR spectra. The ee can be calculated simply from integration of the $^1$H and/or $^7$Li NMR spectra.We thank the EU for a Marie Curie Intra European Fellowship within the seventh European Community Framework Programme (R. G. R.) and an Advanced Investigator Award (D. S. W.). We also thank the Fonds der Chemischen Industrie and the Studienstiftung des deutschen Volkes (Scholarships for S. H.)

Flexible Bonding of the Phosph(V)azane Dianions [S(E)P(µ-NtBu)]22-

Oxidation of the P(III) dianion [S-P(µ-NtBu)]22- (1) with elemental sulphur, selenium and tellurium gives the P(V) dianions [(S)(E)P(µ-NtBu)]22- (E = S (6a), Se (6b), Te (6c)). Although 6c proves to be too unstable, the S,S-dianion 6a and ambidentate S,Se-dianion 6b are readily transferred intact to main group and transition metal elements, producing a range of new cage and coordination compounds. While their coordination characteristics are in many ways similar to closely-related isoelectronic phosph(V)azane anions [(E)(RN=)P(µ-NtBu)]22-, the sterically unhindered nature of 6 introduces an expanded range of coordination modes, i.e., facial S,S- and Se,Se-bonding as well as side-on S,Se-coordination. All of these bonding modes are observed for the amibidentate S,Se dianion 6b.We thank the EU (ERC Advanced Grant for DSW, Erasmus grant for AJP), Cambridge Australia Scholarships (FJR) and the Cambridge Trust (AJP, FJR) and the PPF (AJP) for funding and the Spanish MINECO-AEI and the European Union (ESF) for a Ramon y Cajal contract (RG-R, RYC-2015–19035)

Tuning of Human Modulation Filters Is Carrier-Frequency Dependent

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