The performance of a multi guard ring (MGR) diode for clinical electron beams dosimetry.

The dosimetric response of a multi guard ring structure (MGR) diode has been studied with clinical electron beam energies from 5 MeV to 15 MeV. The results showed that the MGR dose response is linear in the range of 5-320 cGy and presents reproducibility with variation coefficients less than 0.4%. The field output factors measured with the MGR agreed within 2% with those measured with an ionization chamber. This study evidences that this diode can be used for clinical electron beam dosimetry.

Assessing soil erosion risk using RUSLE through a GIS open source desktop and web application.

Soil erosion is a serious environmental problem. An estimation of the expected soil loss by water-caused erosion can be calculated considering the Revised Universal Soil Loss Equation (RUSLE). Geographical Information Systems (GIS) provide different tools to create categorical maps of soil erosion risk which help to study the risk assessment of soil loss. The objective of this study was to develop a GIS open source application (in QGIS), using the RUSLE methodology for estimating erosion rate at the watershed scale (desktop application) and provide the same application via web access (web application). The applications developed allow one to generate all the maps necessary to evaluate the soil erosion risk. Several libraries and algorithms from SEXTANTE were used to develop these applications. These applications were tested in Montalegre municipality (Portugal). The maps involved in RUSLE method-soil erosivity factor, soil erodibility factor, topographic factor, cover management factor, and support practices-were created. The estimated mean value of the soil loss obtained was 220 ton km(-2) year(-1) ranged from 0.27 to 1283 ton km(-2) year(-1). The results indicated that most of the study area (80 %) is characterized by very low soil erosion level (<321 ton km(-2) year(-1)) and in 4 % of the studied area the soil erosion was higher than 962 ton km(-2) year(-1). It was also concluded that areas with high slope values and bare soil are related with high level of erosion and the higher the P and C values, the higher the soil erosion percentage. The RUSLE web and the desktop application are freely available.

Renal transplantation in type 1 diabetes mellitus: an unusual case report.

Diabetes mellitus (DM) may progress to diabetic nephropathy (DN) in approximately 40% of cases and it accounts for one of the most common causes of end-stage of renal disease (ESRD). The pathogenesis of DN involves complex interactions between metabolic and hemodynamic factors. DM type 1 has a dominant impact on morbidity and mortality after renal transplantation. We report a kidney transplantation patient with DM and DN as the etiology of end-stage renal disease and whose post-transplantation evolution over 19 years was remarkably atypical. DM was diagnosed at the age of 7 years and the patient suffered a rapid and aggressive progression of her disease with early development of DN and diabetic retinopathy. Nineteen years post-transplantation, the patient shows neither deterioration of graft function nor clinical reactivation of DN. There seems to be two quite distinct answers to the same injury supported by a group of factors that led to micro- and macrovascular lesions, all present before transplantation and potentially aggravated through some immunosuppressive therapy. This clinical evolution suggests the hypothesis that not only the graft but also the donor may have inherent characteristics that enabled him to display the resistance to DN despite the genetic susceptibility of the receptor. The answers to these questions would help to explain why some patients with diabetes progress to macro- and microvascular complications and others remain resistant to developing these vascular disorders. In this case, the resistance to DN is apparently a feature related to the donor.

Diagnosis of the infection by the Helicobacter pylori through stool examination: method standardization in adults.

OBJECTIVES: Infection caused by Helicobacter pylori (H. pylori) is one of the most common causes of chronic infection in the world. The presence of the infection is strongly associated with the neoplasia of the gastrointestinal tract, and its diagnosis is easily made by means of invasive or non-invasive methods. Among such methods, the H. pylori antigen detection in stool through ELISA technique is easily performed and it is an alternative to endoscopy in children, since this exam is not usually indicated in this age group. The aim of the current study is to establish the standardization of the ELISA method for the detection of H. pylori in stool specimens in Brazil. DESIGN AND METHODS: Patients between 18 and 70 years of age were randomly selected in the gastroenterology ambulatory center at Faculdade de Medicina do ABC between 2007 and 2009. They all answered a questionnaire to investigate possible dyspeptic symptoms and then underwent endoscopy and detection of H. pylori through no more than 4 methods. Besides the gastric biopsy, established as the gold standard test, the urease test, the stool ELISA test and serology were also methods applied. RESULTS: The sensitivity and specificity of the exams in this sample were respectively 87.2% and 44% for the stool ELISA test, 41.9% and 64% for serology, 65.6% and 58.8% for the urease test and 100% and 80.8% for the clinical analysis. CONCLUSIONS: The ROC curve showed a good correlation between the compared methods. In Brazil the standardization of the ELISA test for the detection of H. pylori in stool specimens constitutes a non-invasive diagnostic alternative.

New law of renal transplantation in Portugal associated with more acute rejection episodes and higher costs.

The new law implemented in August 2007 changed the criteria to select renal transplantation (RT) candidates in Portugal, favoring hyperimmunized subjects and those on the waiting list for a longer time, making human leukocyte antigen (HLA) compatibilities less important. The authors compared patients who received a deceased donor kidney between 2005 and 2010. Patients were divided in group A who underwent transplantation before August 2007 (n = 132) and group B (n = 125) after that date. We considered a value of P < .05. Overall mean age at RT was 46.6 ± 13.9 years with 58.8% men, 88% on hemodialysis (HD), with a mean dialysis time of 82.8 ± 119 months. Also, 10.5% of patients underwent a previous transplantation. The mean follow-up was 35 ± 17.1 months. Group B showed significant adverse differences, including dialysis time (50.9 vs. 117 months), length of hospitalization (14.4 vs. 23.2 days), need for HD (1 vs. 3.4 days), HLA match (3.3 vs. 1.4 compatibilities), previous sensitization (4.4% vs. 21.7%), acute rejection episodes in the 1st year (23% vs. 37%), greater use of immunosuppressive drugs, higher costs of induction therapy (2790 vs 4360ϵ), and greater costs of drugs during first hospitalization (3456 vs. 7144ϵ). Among the 16 subjects who lost their grafts, 7 were in group A (3 in the first year) and 9 in group B all in the first year. There was a 5.1% decrease in graft survival at 12 months (P = .07). Univariate analysis showed an association of acute rejection episodes with HLA mismatches, hyperimmunized patients, absence of immediate graft function, hospitalization time, longer HD need, and higher creatinine level at months 1, 2, 3, and 6. Multivariate analysis revealed acute rejection episodes to be associated with a lower number of HLA compatibilities (odds ratio = 0.65; 95% confidence interval, [0.46-0.9]). Application of the law has led to a greater number of acute rejection episodes in the first year and increased costs.

Experimental investigation on the effect of liquid injection by multiple orifices in the formation of droplets in a Venturi scrubber.

Venturi scrubbers are widely utilized in gas cleaning. The cleansing elements in these scrubbers are droplets formed from the atomization of a liquid into a dust-laden gas. In industrial scrubbers, this liquid is injected through several orifices so that the cloud of droplets can be evenly distributed throughout the duct. The interaction between droplets when injected through many orifices, where opposite clouds of atomized liquid can reach each other, is to be expected. This work presents experimental measurements of droplet size measured in situ and the evidence of cloud interaction within a Venturi scrubber operating with multi-orifice jet injection. The influence of gas velocity, liquid flow rate and droplet size variation in the axial position after the point of the injection of the liquid were also evaluated for the different injection configurations. The experimental results showed that an increase in the liquid flow rate generated greater interaction between jets. The number of orifices had a significant influence on droplet size. In general, the increase in the velocity of the liquid jet and in the gas velocity favored the atomization process by reducing the size of the droplets.

Atomization of liquids in a Pease-Anthony Venturi scrubber. Part II. Droplet dispersion.

Droplet distribution is of fundamental importance to the performance of a Venturi scrubber. Ensuring good liquid distribution can increase performance at minimal liquid usage. In this study, droplet dispersion in a rectangular Pease-Anthony Venturi scrubber, operating horizontally, was examined both theoretically and experimentally. The Venturi throat cross-section was 24 mm x 35 mm, and the throat length varied from 63 to 140 mm. Liquid was injected through a single orifice (1.0 mm diameter) on the throat wall. This arrangement allowed the study of the influence of jet penetration on droplet distribution. Gas velocity at the throat was 58.3 and 74.6 m/s, and the liquid flow rate was 286, 559 and 853 ml/min. A probe with a 2.7 mm internal diameter was used to isokinetically remove liquid from several positions inside the equipment. It was possible to study liquid distribution close to the injection point. A new model for droplet dispersion, which incorporates the new description of the jet atomization process developed by the present authors in the first article of this series, is proposed and evaluated. The model predicted well the experimental data.

Response of PIN diodes as room temperature photon detectors.

In this work we have studied the direct detection and spectrometric capabilities of low-cost commercial silicon photodiodes for X- and gamma-rays (energies from 10 up to 80 keV) envisaging their use in characterization of porous microstructures by X-ray microtomography. The best values of the energy resolution for the 59.5 keV 241Am gamma-ray line, measured at room temperature, were found to be 2.1 and 1.8 keV for SFH00206K (Siemens) and S2506-04 (Hamamatsu) PIN diodes, respectively.

Atomization of liquids in a Pease-Anthony Venturi scrubber. Part I. Jet dynamics.

Jet dynamics, in particular jet penetration, is an important design parameter affecting the collection efficiency of Venturi scrubbers. A mathematical description of the trajectory, break-up and penetration of liquid jets initially transversal to a subsonic gas stream is presented. Experimental data obtained from a laboratory scale Venturi scrubber, operated with liquid injected into the throat through a single orifice, jet velocities between 6.07 and 15.9 m/s, and throat gas velocities between 58.3 and 74.9 m/s, is presented and used to validate the model.

A Portuguese palliative care unit.

The background to the development of the first Portuguese palliative care unit is described. The activities of this pioneer unit in Porto, which include patient assistance, teaching and research, are reported, and the paper closes with some general thoughts on the possible ways of providing a more rapid response to the suffering of patients with far advanced chronic diseases in an environment where palliative care is not yet well developed.

Evaluation of the models available for the prediction of pressure drop in venturi scrubbers.

The major running cost derived from the operation of venturi scrubbers is pressure drop. In the present study, the predictions of different models are compared to experimental data from venturi scrubbers of different sizes (throat diameter from 1.9 to 16cm), geometries, operating variables and liquid injection arrangements. As a result, it is concluded that most of the models must be used with caution. Much attention must be paid to the validity of the assumptions employed in the mathematical models. The equations proposed by Calvert [Scrubbing, Air Pollution, 3rd Edition, Vol. IV, Academic Press, New York, 1982], Yung et al. [JAPCA 27 (1977) 348] or Hesketh [Atomization and cloud behaviour in wet scrubbers, in: Proceedings of the US-USSR Symposium Control Fine Particulate Emissions 1974, San Francisco, 15-18 January 1974] produce good results only in very specific situations. The model proposed by Boll [Ind. Eng. Chem. Fundam. 12 (1973) 40] is simple, easy to compute and agrees reasonably well with the experimental data. Unfortunately, it cannot predict the effect of different liquid injection arrangements. The model by Azzopardi and coworkers [Filtr. Sep. 21 (1984) 196; Trans. IchemE. 69B (1991) 237; Chem Eng. J. 67 (1997) 9] was the only one to give good predictions for all the range of variables studied. On the other hand, this model is not simple and requires from the engineer an additional effort in terms of computation. In order to apply this model to the rectangular geometry, the concept of hydraulic equivalent diameter was used.

Factors influencing outcome of prolonged norepinephrine therapy for shock in critical surgical illness.

Several studies indicate that norepinephrine (NE) may be more effective than dopamine for the treatment of septic shock. Nonetheless, many consider dopamine to be the pressor of choice for shock refractory to volume resuscitation. Owing to fear of excessive vasoconstriction, accentuated end-organ hypoperfusion, and the development of multiple organ dysfunction syndrome (MODS), it is contended that NE may be deleterious. We analyzed the duration of NE use and the variables that predict mortality in a consecutive cohort of 406 surgical intensive care unit patients treated with NE for shock. Study parameters included age, acute physiology and chronic health evaluation (APACHE) II and APACHE III scores, hospital (HLOS) and intensive care unit (ULOS) length of stay, maximal and daily multiple organ dysfunction (MOD) scores, MOD score minus cardiovascular points (MOD-CV), duration of NE infusion, and survival. The duration of NE infusion was stratified into six subsets (1, 2, 3-5, 6-10, 11-20, and > or =21 days). An age- and APACHE II and III score-matched cohort of 195 patients, in whom NE was not utilized, was identified retrospectively for comparison. The prevalence of NE use was 10.9%. NE patients developed MODS to a greater degree (11.7 +/- .3 vs. 5.9 +/- .4 points, p < .0001). NE patients had a greater degree (p < .0001) of noncardiovascular MOD as well. When stratified by survival, a greater degree of MOD occurred in both nonsurvivors and survivors of NE (both, p < .0001) compared with comparably ill patients without pressor-dependent shock. MOD scores, ULOS, and HLOS increased progressively with prolonged NE therapy (all, p < .0005), whereas mortality increased significantly only when the duration of NE infusion exceeded 10 days (p = .05). By multivariate analysis of variance (ANOVA), MOD score (p < .0001), and APACHE III (p < .01) predicted mortality, but notably the duration of NE therapy failed to attain predictive value (p = .3192). Only the MOD score was predictive of HLOS (p = .0001) and ULOS (p = .003). Daily MOD scores revealed that nonsurvivors of NE therapy were admitted to the intensive care unit with a greater degree of baseline organ dysfunction than NE survivors (7.5 +/- .4 vs. 5.1 +/- .2 for survivors, p < .0001). In addition, whereas survivors showed significant improvement by Day 5 (p < .01), MOD amongst nonsurvivors remained unchanged (p = .993). Although critically ill surgical patients requiring NE support have significantly greater degrees of organ dysfunction than patients not requiring pressors, much of the organ dysfunction is present on admission. The data contradict the notion that NE facilitates the development of MODS.

Efficacy of nutritional pharmacology in surgical patients.

The present article reviews the current concepts of immune enhancement through nutritional support for the surgical patient as they are derived experimentally and clinically. Although the potential for altering outcome in surgical patients through nutritional enhancement exists, the authors caution against overzealous application of laboratory data in the clinical arena. Available clinical studies have, at best, only demonstrated modest benefits. It is appropriate that the current literature be critically reviewed to assess the efficacy of the agent(s) purported to be of clinical benefit. Although present reports of immune-enhancing nutrition regimens demonstrate no overwhelming benefits in the critically ill or immunocompromised patient, the pursuit of this science remains undaunted. Lessons learned from the past are leading to reinvestigations in the laboratory, as well as better designs of clinical trials that are free of distracting post-hoc analysis and performed clearly in an intention-to-treat manner.

Aerobic degradation of 2-sulphobenzoic acid by Pseudomonas strain SB(W).

A 2-sulphobenzoic acid-degrading bacterium, Pseudomonas sp. strain SB(W), was isolated from creosote-contaminated soil. It used this compound as its sole carbon, sulphur and energy source, and gave a nearly stoichiometric release of sulphate from 2-sulphobenzoic acid. It did not grow on 3- to 4- sulphobenzoic acids. Isolated SB(W) produced two transient metabolites. The first to appear, and the more abundant metabolite, was identified as 2,3-dihydroxybenzoic acid. The second metabolite was identified as salicylic acid. Both of these compounds served as growth substrates for the isolates.

Microbially Mediated Formation of Benzonaphthothiophenes from Benzo[b]thiophenes.

Studies of the microbial metabolism of benzo[b]thiophene (molecular weight 134) by three Pseudomonas isolates showed the formation of benzothiophene sulfoxide, benzothiophene sulfone, and a sulfur-containing metabolite with a molecular weight of 234. Desulfurization of the high-molecular-weight product with nickel boride gave 1-phenylnaphthalene, indicating that the metabolite was benzo[b]naphtho[1,2-d]thiophene. Similarly, the isolates were capable of producing the analogous dimethyl-substituted benzonaphthothiophenes from methylbenzothiophenes that had the methyl substitution on the benzene ring. The formation of benzo[b] naphtho[1,2-d]thiophene was also observed when a petroleum-degrading mixed culture was incubated with benzothiophene-supplemented Prudhoe Bay crude oil. Investigations into the mechanism of formation of these high-molecular-weight compounds showed that they resulted from an abiotic, Diels-Alder-type condensation of two molecules of the sulfoxide, which were microbially produced from the respective benzothiophene, with the subsequent loss of two atoms of hydrogen and oxygen and one atom of sulfur. The condensation products also formed from the sulfoxides of benzothiophene and methylbenzothiophenes when the sulfoxides were enzymatically synthesized by oxidation of the benzothiophene with horse heart cytochrome c and H(2)O(2).