The mineral phase quantification of vermiculite and interstratified clay minerals-containing ores by X-ray diffraction and Rietveld method after K cation exchange

Hydrothermal transformations and weathering are important mineralizing processes in carbonatite-related ores. But the transformation products of mafic minerals, such as the clay minerals, vermiculite and interstratified phases, preclude the use of X-ray diffraction, particularly the Rietveld method, for mineral phase quantification. After treatment with KCl, vermiculite and interstratified phases (all peaks roughly at 1.2, 1.4-1.5 and 2.4 nm) are converted to a phlogopite-like structure with d(0 0 1) = 1.0 nm, which can successfully be refined. The method was tested using three carbonatite-derived ores, with a total phlogopite-like phase content ranging from 1.2 to 32.3 wt.%. Comparison of the chemical analyses with the calculated chemical composition, based on the phase quantification and the mineral composition is in good agreement for major elements, such as Si, Fe and Al. For P results were also very good, but Ti and Nb are generally underestimated, and Ba is overestimated. Minerals with lower contents, as pyrochlore, approach the diffraction detection limit. Problems to accurately determine mineral composition for some of the phases also impacts on the reconciliation. The chemical composition of the pyrochlore group minerals changed, but not to an extent to constrain the usefulness of the technique. Cation exchange successfully extended the amenability of the Rietveld method for phase quantification.     

DRYING OF BIOLOGICAL PRODUCTS WITH SIGNIFICANT VOLUME VARIATION. EXPERIMENTAL AND MODELING RESULTS FOR POTATO DRYING.

This work is devoted to the experimental investigation and theoretical modeling of biological products with high initial moisture content which implies significant volume contraction. Firstly, experimental equipment which was designed to continuously determine variations in the global moisture content and in the temperature of the sample is introduced. Furthermore, the equipment is controlled by a PC which records experimental information in real time. In particular, measurement of the radial and temporal distributions of moisture content and temperature during the drying process of the homogeneous porous media potato are given. The mean moisture content and temperature curves are also given.     

Hydrogeological and geothermal changes in karstic reservoirs due to mine dewatering

Lowering of the piezometric-head due to pumping to protect mines from water-inrushes can create an extensive cone of depression. As a result of this, the directions of ground water flow in the surrounding aquifers can be changed, which can be sensitively indicated by the changes in water-temperature. In the bauxite deposits of Hungary the regular temperature measurements in the piezometric boreholes and observation wells, makes it possible to monitor, in combination with other methods, the hydrological structure of the surrounding rock mass.     

DNA polymorphism detection in Tribolium castaneum (HERBST) (Coleoptera: Tenebrionidae): potential use in stored product pest management

PURPOSE: To evaluate long-term efficacy of double balloon percutaneous mitral valvuloplasty technique (PMV2B). METHODS: Sixty-eight patients (76% female), mean-age 32 (15-69) years who had been submitted to PMV2B, that completed clinical and echodopplercardiographic one year follow-up (PO12M). Admission criteria were: exertional dyspnoea, no thromboembolism antecedent up to three months before the procedure, absence of other cardiac disease requiring correction, an admissible echodopplercardiographic score, absence of intracavitary thrombus and mitral regurgitation absent or minor. RESULTS: The patients were divided in two groups: group A of 7 (11%) patients that have a cardiac event in this period, and group B of 61 patients that completed the follow-up without a cardiac event. In group A three patients have had a severe mitral regurgitation, one case was unsuccessful and other one had a re-stenosis. There were two deaths, not related to the intervention. In group B, haemodynamic results before and immediately after PMV2B (POI) showed a significant improvement, except in relation to cardiac index. There was an increase in the grade of mitral regurgitation in 17 (28%) patients and in two cases this regurgitation became moderate. The mitral valvar area (MVA) variation between PRE x POI x PO12M presented, comparing MVA between POI and PO12M, a significant reduction. Two (3%) patients with a reduction greater than 50% of the initial increase, 33 (54%) between 10 and 50% and 26 (42%) less that 10% remained in functional class I/II. CONCLUSION: PMV2B is an attractive treatment to select symptomatic mitral stenosis patients, with a low incidence of complications, symptomatic effective improvement that was maintained in one year follow-up, although there was a reduction in MVA.     

Fiber optic hot-wire flowmeter based on a metallic coated hybrid long period grating/fiber Bragg grating structure

In this work an all-optical hot-wire flowmeter based on a silver coated fiber combining a long period grating and a fiber Bragg grating (FBG) structure is proposed. Light from a pump laser at 1480 nm propagating down the fiber is coupled by the long period grating into the fiber cladding and is absorbed by the silver coating deposited on the fiber surface over the Bragg grating structure. This absorption acts like a hot wire raising the fiber temperature locally, which is effectively detected by the FBG resonance shift. The temperature increase depends on the flow speed of the surrounding air, which has the effect of cooling the fiber. It is demonstrated that the Bragg wavelength shift can be related to the flow speed. A flow speed resolution of 0.08 m/s is achieved using this new configuration.     

Incidence of and risk factors for hepatitis B virus and hepatitis C virus infection among haemodialysis and CAPD patients: evidence for environmental transmission

Hepatitis B virus (HBV) serum markers (HBsAg, anti-HBs, anti-HBc) and antihepatitis C antibody (anti-HCV) were prospectively followed in haemodialysis and CAPD patients. From January 1987 to January 1990, 185 patients on haemodialysis and 124 on CAPD were analysed. Among patients susceptible to HBV (69 on haemodialysis and 70 on CAPD), there were 17 HBsAg seroconversions on haemodialysis (0.19/patient-year) and 1 on CAPD (0.01/patient-year). A Cox proportional hazards model showed that haemodialysis treatment was the only risk factor significantly associated with HBV infection, thus suggesting transmission through the environment. Regarding hepatitis C, 83 anti-HCV-negative patients on haemodialysis and 46 on CAPD were followed. There were 18 seroconversions on haemodialysis (0.15/patient-year) and two seroconversions on CAPD (0.03/patient-year). Haemodialysis treatment was also the only risk factor significantly associated with a higher risk of HCV infection. The hazard ratio for HCV infection in haemodialysis patients was 5.7 compared to CAPD patients. Nevertheless, for one patient on CAPD treatment transfusions were the only possible source of HCV infection. In conclusion, both viruses were transmitted mainly through the haemodialysis environment, but the role of transfusions could not be excluded.     

The use of non-human primates as animal models for the study of hepatitis viruses

Hepatitis viruses belong to different families and have in common a striking hepatotropism and restrictions for propagation in cell culture. The transmissibility of hepatitis is in great part limited to non-human primates. Enterically transmitted hepatitis viruses (hepatitis A virus and hepatitis E virus) can induce hepatitis in a number of Old World and New World monkey species, while the host range of non-human primates susceptible to hepatitis viruses transmitted by the parenteral route (hepatitis B virus, hepatitis C virus and hepatitis delta virus) is restricted to few species of Old World monkeys, especially the chimpanzee. Experimental studies on non-human primates have provided an invaluable source of information regarding the biology and pathogenesis of these viruses, and represent a still indispensable tool for vaccine and drug testing.     

The influence of meat consumption on dietary data, iron status and serum lipid parameters in young women

The outcome of adjusting health care spending to the overall economic performance of the country has become a major issue of health care policy of the industrialized nations. How can progress in medicine be consistently financed under the restriction of fixed contributions to mandatory sickness funds? Medical Technology Assessment is an interdisciplinary concept that proposes solutions to this issue. This article discusses the concept of Medical Technology Assessment and shows how Medical Technology Assessment should be implemented into the health care system. This article depicts how Medical Technology Assessment is implemented in the United States of America, in the United Kingdom and in the Netherlands. It also discusses which institutions take steps towards Medical Technology Assessment in Germany. The second article examines how to implement Medical Technology Assessment into the German health care system.     

Influence of an oligodendroglial component on the survival of patients with anaplastic astrocytomas: a report of Radiation Therapy Oncology Group 83-02

PURPOSE: Seven percent of patients with high grade gliomas enrolled in RTOG 83-02 had mixed astrocytoma/oligodenroglial elements on central pathology review. It has often been assumed that the most aggressive histologic component of a tumor determines biologic behavior; however in this trial, the survival of patients who had mixed glioblastomas/oligodenrogliomas was significantly longer than that of patients with pure glioblastomas (GBM). We therefore evaluated the effect of an oligodendroglial component on the survival of patients who had anaplastic astrocytomas (AAF) treated in the same trial. METHODS AND MATERIALS: One hundred nine patients who had AAF and 24 patients with mixed AAF/oligodendrogliomas (AAF/OL) were enrolled in a Phase I/II trial of randomized dose-escalation hyperfractioned radiotherapy plus BCNU. AAF/OL patients were older and more likely to have had more aggressive surgery than AAF patients. Other pretreatment characteristics were balanced between groups, as was assigned treatment. RESULTS: The median survival time for AAF was 3.0 years versus 7.3 years for AAF/OL (p = 0.019). In a multivariate analysis, adjusting for extent of surgical resection and age, an oligodendroglial component was an independent prognostic factor for survival. CONCLUSION: The results support the concept that AAFs with an oligodendroglial component have a better prognosis than pure AAF tumors, similar to the effect seen among patients with glioblastoma multiforme tumors. This better survival outcome should be taken into consideration in the design and stratification of future trials. Additionally, in contrast to patients with GBMs, patients who have AAF/OL have the potential for prolonged survival; therefore, late sequelae of treatment (both radiation and chemotherapy) must be weighed more heavily in the benefits to risks analysis.     

Assessment of the effects of various UV sources on inactivation and photoproduct induction in phage T7 dosimeter

Left ventricular pseudoaneurysm following acute myocardial infarction generally has an extremely poor prognosis without surgical repair. A rare case of long term survival for 23 years following cardiac rupture with subsequent development of a left ventricular pseudoaneurysm after acute myocardial infarction is reported. The patient suffered acute inferoposterior myocardial infarction in July 1974 at the age of 58 years. Clinical course and findings obtained on reassessment in 1992 (transesophageal echocardiography, chest computed tomography and left ventriculography) confirmed a left ventricular pseudoaneurysm. The patient refused surgical resection of the lesion, but remained alive and well in 1997 (81 years old). In this case, it is considered that containment of hemorrhage by pericardial adhesion prevented immediate tamponade and sudden death.