Characterization of semi-packed columns with different cross section in high-pressure gas chromatography.

Hydrodynamics, efficiency, and loading capacity of two semi-packed columns with different cross sections (NANO 315 µm x 18 µm; CAP 1000 µm x 28 µm) and similar pillar diameter and pillar-pillar distance (respectively 5 µm and 2.5 µm) have been compared in high-pressure gas chromatography. A flow prediction tool has been first designed to determine pressure variations and hold-up time across the chromatographic system taking into account the rectangular geometry of the ducts into the semi-packed columns.

A Sensitive Micro Conductometric Ethanol Sensor Based on an Alcohol Dehydrogenase-Gold Nanoparticle Chitosan Composite.

In this paper, a microconductometric sensor has been designed, based on a chitosan composite including alcohol dehydrogenase-and its cofactor-and gold nanoparticles, and was calibrated by differential measurements in the headspace of aqueous solutions of ethanol. The role of gold nanoparticles (GNPs) was crucial in improving the analytical performance of the ethanol sensor in terms of response time, sensitivity, selectivity, and reproducibility. The response time was reduced to 10 s, compared to 21 s without GNPs.

Dual detection chromatographic method for fast characterization of nano-gravimetric detector.

Nano-gravimetric detector (NGD) has been recently introduced as miniaturized gas chromatography detector. The NGD response is based on an adsorption-desorption mechanism of compounds between the gaseous phase and the NGD porous oxide layer. The NGD response was characterized by hyphenating NGD in-line with FID detector and a chromatographic column.

Laparoscopic Liver Resection: A South American Experience with 2887 Cases.

Background: Laparoscopic liver resections (LLR) have been increasingly performed in recent years. Most of the available evidence, however, comes from specialized centers in Asia, Europe and USA. Data from South America are limited and based on single-center experiences.

Hyphenation of short monolithic silica capillary column with vacuum ultraviolet spectroscopy detector for light hydrocarbons separation.

Compared to conventionnal bench top instruments, on-line GC analyzers require specific characteristics. On one hand, for some applications operating with a reactor pressure as high as several tens of bars, sample pressure has to be reduced before GC separation, or specific valves and columns have to be designed to perform separation with high carrier gas inlet pressure. On the other hand, informative detectors such as mass spectrometer are valuable but low maintenance detectors are prefered.

Highly Sensitive Voltammetric Glucose Biosensor Based on Glucose Oxidase Encapsulated in a Chitosan/Kappa-Carrageenan/Gold Nanoparticle Bionanocomposite.

In this work, an enzymatic sensor, based on a bionanocomposite film consisting of a polyelectrolyte complex (PEC) (Chitosan/kappa-carrageenan) doped with gold nanoparticles (AuNPs) encapsulating glucose oxidase (GOD) deposited on a gold electrode (Au) for glucose sensing, is described. Using the electrocatalytic synergy of AuNPs and GOD as a model of enzyme, the variation of the current (µA) as a function of the log of the glucose concentration (log [glucose]), shows three times higher sensitivity for the modified electrode (283.9) compared to that of the PEC/GOD modified electrode (93.

Is vacuum ultraviolet detector a concentration or a mass dependent detector?

The vacuum ultraviolet detector (VUV) is a very effective tool for chromatogram deconvolution and peak identification, and can also be used for quantification. To avoid quantitative issues in relation to time drift, such as variation of peak area or peak height, the detector response type has to be well defined. Due to the make-up flow and pressure regulation of make-up, the detector response (height of the peak) and peak area appeared to be dependent on experimental conditions such as inlet pressure and make-up pressure.

Behavior of macroporous vinyl silica and silica monolithic columns in high pressure gas chromatography.

80% vinyltrimethoxysilane-based hybrid silica monoliths (80-VTMS), which have been initially developed for separation in reversed-phase liquid chromatography, have been investigated in high pressure gas chromatography separations (carrier gas pressure up to 60bar) and compared to silica monolithic columns. The behavior of both silica and 80-VTMS monolithic columns was investigated using helium, nitrogen and carbon dioxide as carrier gas. The efficiency of 80-VTMS monolithic columns was shown to vary differently than silica monolithic columns according to the temperature and the carrier gas used.

Behavior of short silica monolithic columns in high pressure gas chromatography.

In order to analyze light hydrocarbons mixtures with silica monolithic columns, a conventional gas chromatograph was modified to work with carrier gas pressure as high as 60bar. To understand hydrodynamic flow and retention with short columns (less than 30cm), special attention was required due to the temperature difference between the oven area and the FID detector which contain a significant length of the column. Efficiency and selectivity using various carrier gases (helium, nitrogen and carbon dioxide) at different inlet pressure for different oven temperature were studied.

Pectin gelation with chlorhexidine: Physico-chemical studies in dilute solutions.

Low methoxyl pectin is known to gel with divalent cations (e.g. Ca(2+), Zn(2+)).

[Liver resection for non tumoral liver disease. Multicentric experience in Argentina].

Background: The role of liver resection (LR) in patients with non-tumoral hepatic disease (NTHD) remains controversial.

Objective: To analyze the indications and outcomes of liver resections in patients with NTHD.

Methods: A retrospective analysis in a multicentric data base was performed.

[Radical surgery for incidental gallbladder cancer: the value of a deferred pathological finding of residual disease].

Background: Surgical treatment of gallbladder cancer is still controversial. The extent of the radical surgery and its therapeutic efficacy continue to be debated.

Objective: Analyze the efficacy of radical resection in patients with incidental gallbladder cancer evaluating the presence of residual disease in the resection specimen and analyzing the associated factors of survival.

Relevance of residual disease after liver resection for incidental gallbladder cancer.

Objectives: In patients diagnosed with incidental gallbladder cancer (GC), the benefit and optimal extent of further surgery remain unclear. The aims of this study were to analyse outcomes in patients who underwent liver resection following a diagnosis of incidental GC and to determine factors associated with longterm survival.

Methods: A retrospective analysis of patients diagnosed with incidental GC between June 1999 and June 2010 was performed.

[Study of prognostic factors in the hepatectomy for metastases of colorectal carcinoma--analysis of two scores].

Background: Resection is the treatment of choice for colorectal cancer liver metastases.

Objective: This is a retrospective, longitudinal, retrospective analysis of different prognostic factors for survival in a consecutive series of liver resection for metastatic colorectal carcinoma.

Patients And Methods: Between October 1998 and November 2007, we performed 89 liver resections for colorectal metastases.

Caroli's disease: report of surgical options and long-term outcome of patients treated in Argentina. Multicenter study.

Background: Caroli's disease (CD) management is still controversial.

Aim: The purpose of this study is to report the most frequent clinical features, treatment options, and outcome obtained after surgical management of CD.

Methods: A voluntary survey was conducted.

Liver transplantation in adult patients with portal vein thrombosis: risk factors, management and outcome.

Background: Portal vein thrombosis (PVT) is a well recognized complication of patients with end-stage cirrhosis and its incidence ranges from 2 to 26%. The aim of this study was to analyze the results and long-term follow-up of a consecutive series of liver transplants performed in patients with PVT and compare them with patients transplanted without PVT.

Patients And Methods: Between July 1995 and June 2006, 26 liver transplants were performed in patients with PVT (8.

Liver resection for non-colorectal, non-neuroendocrine metastases: analysis of a multicenter study from Argentina.

Background And Aim: Resection of colorectal liver metastases has become a standard of care, although the value of this procedure in non-colorectal non-neuroendocrine (NCRNNE) metastases remains controversial and is still a matter of debate. The aim of the study was to determine the utility of liver resection in the long-term outcome of patients with NCRNNE metastases.

Material And Methods: The records of 106 patients who underwent liver resection for NCRNNE metastases in the period 1989 to 2006 at 5 HPB Centers in Argentina were analyzed.

[Diminution of antifungal activity of fluconazole associated with ibuprofen and piroxicam in experimental histoplasmosis of hamsters (Mesocricetus auratus)].

The aim of this study was to determine if tha association of non-steroid antiinflammatory drugs (piroxicam and ibuprofen) with fluconazole, affects the antifungal activity of the azole compound, in an experimental model histoplasmosis in hamsters (Mesocricetus auratus). Sixty hamsters were intracardially inoculated with 4x10(6) yeasts of Histoplasma capsulatum var. capsulatum.