Two-Phase (Solid-Liquid) Flow in Inclined Pipes

This paper presents an experimental research about the behavior of two-phase flows in inclined pipes. The inclination angle varied from 5° to 45° and the slurry solid concentration varied up to 15%. It was concluded that the head losses of the downward sloping pipe flow are always lower than the head losses of the horizontal flow and these are always lower than the head losses of the upward sloping pipe flow, regardless the concentration and inclination angle. It was possible to develop empirical equations to calculate the head losses of the horizontal flow and the upward and downward sloping pipe flows.

Bubble-Bubble Interaction in Horizontal Two-Phase Slug Flow

Modelling of the slug structure requires a new effort on fundamental research. To clarify some aspects of the horizontal slug flow, an experimental study of the behaviour of two isolated bubbles in a single-phase liquid flow was performed. This procedure was adopted to avoid the overlap of different phenomena induced by a train of long bubbles. The experimental facility consists of a 90-m horizontal PVC pipe with internal diameter of 0,053 m. The behaviour of two single air bubbles travelling in a water flow was studied. Focus was given on the influence of the distance between the bubbles on the velocity of the second bubble. This study allows the understanding of the mechanism of overtaking that takes place right after the slug formation and that precedes the coalescence of bubbles in a slug flow. The results show that bubbles placed behind a liquid slug smaller than a critical value move faster than the leading one. Otherwise, they move slower than the leading one.

Horizontal Slug Flow in a Large-Size Pipeline: Experimentation and Modeling

The knowledge of the slug flow characteristics is very important when designing pipelines and process equipment. When the intermittences typical in slug flow occurs, the fluctuations of the flow variables bring additional concern to the designer. Focusing on this subject the present work discloses the experimental data on slug flow characteristics occurring in a large-size, large-scale facility. The results were compared with data provided by mechanistic slug flow models in order to verify their reliability when modelling actual flow conditions. Experiments were done with natural gas and oil or water as the liquid phase. To compute the frequency and velocity of the slug cell and to calculate the length of the elongated bubble and liquid slug one used two pressure transducers measuring the pressure drop across the pipe diameter at different axial locations. A third pressure transducer measured the pressure drop between two axial location 200 m apart. The experimental data were compared with results of Camargo's1 algorithm (1991, 1993), which uses the basics of Dukler & Hubbard's (1975) slug flow model, and those calculated by the transient two-phase flow simulator OLGA.

Pressure Drop in Vertical Core-Annular Flow

An experimental apparatus for the study of core annular flows of heavy oil and water at room temperature has been set up and tested at laboratory scale. The test section consists of a 2.75 cm ID galvanized steel pipe. Tap water and a heavy oil (17.6 Pa.s; 963 kg/m³) were used. Pressure drop in a vertical upward test section was accurately measured for oil flow rates in the range 0.297 - 1.045 l/s and water flow rates ranging from 0.063 to 0.315 l/s. The oil-water input ratio was in the range 1-14. The measured pressure drop comprises gravitational and frictional parts. The gravitational pressure drop was expressed in terms of the volumetric fraction of the core, which was determined from a correlation developed by Bannwart (1998b). The existence of an optimum water-oil input ratio for each oil flow rate was observed in the range 0.07 - 0.5. The frictional pressure drop was modeled to account for both hydrodynamic and net buoyancy effects on the core. The model was adjusted to fit our data and shows excellent agreement with data from another source (Bai, 1995).

Hospitalization flow in the public and private systems in the state of Sao Paulo, Brazil

OBJECTIVE To describe the migration flows of demand for public and private hospital care among the health regions of the state of Sao Paulo, Brazil. METHODS Study based on a database of hospitalizations in the public and private systems of the state of Sao Paulo, Southeastern Brazil, in 2006. We analyzed data from 17 health regions of the state, considering people hospitalized in their own health region and those who migrated outwards (emigration) or came from other regions (immigration). The index of migration effectiveness of patients from both systems was estimated. The coverage (hospitalization coefficient) was analyzed in relation to the number of inpatient beds per population and the indexes of migration effectiveness. RESULTS The index of migration effectiveness applied to the hospital care demand flow allowed characterizing health regions with flow balance, with high emigration of public and private patients, and with high attraction of public and private patients. CONCLUSIONS There are differences in hospital care access and opportunities among health regions in the state of Sao Paulo, Brazil.

Calculating rabies virus neutralizing antibodies titres by flow cytometry

The determination of the rabies neutralizing antibody (VNA) response after immunization against rabies is an acceptable index of the efficacy of a vaccine and a successful treatment. Several tests have been developed in attempt to improve the assessment of VNA, from mice inoculation to cell-culture fluorescence inhibition tests. All of them, however, present special difficulties in terms of reading or accuracy. The present study describes a neutralization test performed in cell-culture appraised by flow cytometry (FC). Serial dilutions of the serum samples were mixed in vitro with rabies virus before the addition of BHK-21 cells. After 24h-incubation, cells were released by trypsin treatment, fixed and permeabilized with a p-formaldehyde solution and stained with a rabies virus nucleocapsid protein-specific antibody conjugate. The percentage of virus infection inhibition caused by specific antibodies present in the serum were evaluated in a Beckton & Dickinson FACSCalibur® flow cytometer. A correlation curve between the IU/ml content and the percentage of infective inhibition was built with a reference serum and the VNA titers of serum samples were obtained by extrapolation. Titers obtained by FC and standard test showed an effective pairing results (p < 0.01), with a correlation coefficient (r) = 0.7. These results permit to envisage the FC as a suitable technique to evaluate VNA in sera from immunized animals and likely in human serum samples. Nevertheless, new studies comparing FC to gold-standard techniques are required for determining the FC values of Sensibility and Specificity .

LATERAL FLOW ASSAY FOR CRYPTOCOCCAL ANTIGEN: AN IMPORTANT ADVANCE TO IMPROVE THE CONTINUUM OF HIV CARE AND REDUCE CRYPTOCOCCAL MENINGITIS-RELATED MORTALITY

SUMMARYAIDS-related cryptococcal meningitis continues to cause a substantial burden of death in low and middle income countries. The diagnostic use for detection of cryptococcal capsular polysaccharide antigen (CrAg) in serum and cerebrospinal fluid by latex agglutination test (CrAg-latex) or enzyme-linked immunoassay (EIA) has been available for over decades. Better diagnostics in asymptomatic and symptomatic phases of cryptococcosis are key components to reduce mortality. Recently, the cryptococcal antigen lateral flow assay (CrAg LFA) was included in the armamentarium for diagnosis. Unlike the other tests, the CrAg LFA is a dipstick immunochromatographic assay, in a format similar to the home pregnancy test, and requires little or no lab infrastructure. This test meets all of the World Health Organization ASSURED criteria (Affordable, Sensitive, Specific, User friendly, Rapid/robust, Equipment-free, and Delivered). CrAg LFA in serum, plasma, whole blood, or cerebrospinal fluid is useful for the diagnosis of disease caused by Cryptococcusspecies. The CrAg LFA has better analytical sensitivity for C. gattii than CrAg-latex or EIA. Prevention of cryptococcal disease is new application of CrAg LFA via screening of blood for subclinical infection in asymptomatic HIV-infected persons with CD4 counts < 100 cells/mL who are not receiving effective antiretroviral therapy. CrAg screening of leftover plasma specimens after CD4 testing can identify persons with asymptomatic infection who urgently require pre-emptive fluconazole, who will otherwise progress to symptomatic infection and/or die.

Flow cytometric quantitation of phagocytosis in heparinized complete blood with latex particles and Candida albicans

We report a rapid method for the flow cytometric quantitation of phagocytosis in heparinized complete peripherial blood (HCPB), using commercially available phycoerythrin-conjugated latex particles of 1µm diameter. The method is faster and shows greater reproducibility than Bjerknes' (1984) standard technique using propidium iodide-stained Candida albicans, conventionally applied to the leukocytic layer of peripherial blood but here modified for HCPB. We also report a modification of Bjerknes' Intracellular Killing Test to allow its application to HCPB.

Detection of Mycobacterium leprae infection in wild nine-banded armadillos (Dasypus novemcinctus) using the rapid ML Flow test

Mycobaterium leprae infection was investigated in armadillos from the State of Espírito Santo, Brazil. The ML Flow test was performed on 37 nine-banded armadillos and positive results were found in 11 (29.7%). The ML Flow test may be used to identify possible sources of Mycobaterium leprae among wild armadillos.

Comportamento dos testes sorológicos ML Flow e ELISA (PGL-I) em áreas endêmica e não endêmica de hanseníase

O ML Flow e o ELISA PGL-I são testes sorológicos que detectam anticorpos IgM contra o glicolipídio fenólico I específico do Mycobacterium leprae. Para avaliar o comportamento destes testes em áreas endêmica e não endêmica para hanseníase foram estudados 351 voluntários no Brasil e no Chile, incluindo pacientes com hanseníase, controles sadios, portadores de outras doenças infecciosas, não infecciosas e dermatoses que fazem diagnóstico diferencial com hanseníase. O ponto de corte do ELISA foi estabelecido pelo método da Curva ROC (> 0,157). Em área endêmica, o ML Flow apresentou resultados positivos em 70% dos pacientes com hanseníase; o ELISA foi positivo em 53,3%. Em área não endêmica, o ML Flow foi negativo em todos os voluntários testados; o ELISA foi positivo em 4 voluntários. O ML Flow é um ensaio mais rápido, facilmente aplicável e, portanto, mais adequado para ser utilizado na Atenção Básica; o ELISA necessita, alem de uma infra-estrutura de laboratório adequada, pessoal treinado e especializado em sua execução.

Associação do teste sorológico ML Flow com a baciloscopia

Realizou-se estudo descritivo e exploratório relacionando as covariáveis aos resultados do teste sorológico ML Flow e baciloscopia. Foram estudados 60 casos novos de hanseníase diagnosticados no Centro de Referência em Dermatologia Sanitária. Para a baciloscopia, foi utilizada a coleta de esfregaço dérmico em quatro sítios, sendo o resultado expresso pelo índice bacilocópico. O ML Flow foi registrado de modo qualitativo e semi-quantitativo. Para o estudo da concordância, foi utilizado o índice de Kappa e, para sua interpretação, os critérios de Landis e Koch. Para análise estatística foram realizados a regressão logística e o teste de Kruskal-Wallis. O ML Flow mostrou forte associação com a baciloscopia, observou-se que o aumento gradativo do índice baciloscópico foi acompanhado pelo aumento semi-quantitativo dos níveis de anticorpos medidos pelo ML Flow, tendo sido positivo em 100% dos casos com baciloscopia positiva. Os resultados deste estudo evidenciaram que o ML Flow, por estar fortemente correlacionado à bacilocopia, poderá tornar-se um valioso instrumento auxiliar na classificação e alocação dos pacientes para fins de tratamento.

A influência do teste sorológico ML Flow na classificação da hanseníase

Estudo descritivo e exploratório correlacionando o ML Flow, a baciloscopia e a classificação em paucibacilar (PB) e multibacilar (MB), envolveu 1.041 casos novos com hanseníase em 13 municípios de Minas Gerais, de outubro de 2002 a março de 2004. A concordância entre o ML Flow e a classificação pelo número de lesões cutâneas e a baciloscopia foi moderada (Kappa:0,51 e 0,48, respectivamente) e, substancial (Kappa:0,77) com a classificação final. De janeiro de 2000 a março de 2004, a proporção de casos novos MB no Estado, passou de 78,1 para 65,8%. A queda no percentual de MB foi maior nos serviços participantes da pesquisa ML Flow (73,1 para 53,3%). A diferença de PB e MB nos serviços participantes e não participantes, de janeiro a março de 2004, foi estatisticamente significativa, indicando implicação direta e benéfica no tratamento e no controle da endemia em Minas Gerais.

Fatores de risco para a soropositividade do ML Flow em pacientes com hanseníase

O diagnóstico precoce da hanseníase, a correta classificação e o estudo dos fatores de risco relacionados à soropositividade, tornam-se importantes para o tratamento do doente e controle da endemia, especialmente, quando a responsabilidade pelo atendimento desses pacientes está sendo absorvida pelos serviços de atenção básica. Estudo descritivo e exploratório utilizando regressão logística avaliou a associação das variáveis: sexo, idade, modo de detecção, número de lesões cutâneas e de nervos acometidos, grau de incapacidade, baciloscopia, com o resultado do teste sorológico ML Flow, em 1.072 casos novos com hanseníase em 13 municípios de Minas Gerais. A soropositividade (50,7%) estava estatisticamente associada aos pacientes com 15 anos ou mais de idade (OR:2,6), mais de cinco lesões cutâneas (OR:7,5), mais de um nervo acometido (OR:2,4) e com baciloscopia positiva (OR:5,5 para IB<2 e OR:191,2 para IB>2), colaborando, assim, com a classificação e o tratamento adequados dos doentes.

Sorologia rápida para hanseníase (teste ML Flow) em pacientes dimorfos classificados como paucibacilares pelo número de lesões cutâneas: uma ferramenta útil

A hanseníase ainda é doença endêmica no Brasil, com cerca de 40.000 novos casos por ano. Devido à dificuldade na realização de exames laboratoriais em campo, classifica-se a forma clínica contando-se lesões, o que pode causar subdiagnóstico de casos multibacilares e falha terapêutica. Para avaliar uma nova ferramenta para diagnóstico de hanseníase multibacilar, o teste ML Flow, foi realizado em 21/77 (27,3%) pacientes com hanseníase dimorfa (6 DV e 15 DT) não tratados, com até cinco lesões de pele, avaliados de acordo com a classificação de Ridley & Jopling (R&J). O teste ML Flow foi positivo em 14/21 (66,6%) pacientes (4 DV e 10 DT); em 7/21 (33,3%) pacientes (5 DT e 2 DV) o resultado foi negativo. A classificação da hanseníase baseada somente na contagem de lesões pode falhar em diagnosticar casos MB. O ML Flow é ferramenta útil no diagnóstico de hanseníase dimorfa com até cinco lesões cutâneas.