bluuebunny/crossref_metadata_2025 huggingface dataset:
Two Pediatric Cases of Variant Neurogenic Stress Cardiomyopathy After Intracranial Hemorrhage
Authors: Wittekind Samuel G. , Yanay Ofer , Johnson Erin M. , Gibbons Edward F.
Published: September 2014

Takotsubo cardiomyopathy, also known as stress-induced cardiomyopathy, is an acquired form of left ventricular systolic dysfunction seen in the setting of physiologic stress and the absence of coronary artery disease. It is thought to be caused by excessive sympathetic stimulation. It is well described in the adult literature associated with subarachnoid hemorrhage where it is known as neurogenic stress cardiomyopathy (NSC), but few such pediatric cases have been reported. We describe our experience with 2 children (13- and 10-year-old girls) who presented with spontaneous intracranial hemorrhage followed by pulmonary edema and shock. Echocardiography revealed similar patterns of left ventricular wall motion abnormalities consistent with NSC, inverted Takotsubo variant. One child progressed to death, whereas the other made a remarkable recovery, including significant improvement in cardiac function over the course of 1 week. We argue that at least 1 of these cases represents true stress-induced cardiomyopathy. This report will alert pediatricians to this transient cardiomyopathy that is likely underdiagnosed in pediatric intensive care. We also highlight the challenges of managing both shock and elevated intracranial pressure in the setting of NSC.
Health Care-Associated Infections Among Critically Ill Children in the US, 2007–2012
Authors: Patrick Stephen W. , Kawai Alison Tse , Kleinman Ken , Jin Robert , Vaz Louise , Gay Charlene , Kassler William , Goldmann Don , Lee Grace M.
Published: September 2014

BACKGROUND:

Health care–associated infections (HAIs) are harmful and costly and can result in substantial morbidity for hospitalized children; however, little is known about national trends in HAIs in neonatal and pediatric populations. Our objective was to determine the incidence of HAIs among a large sample of hospitals in the United States caring for critically ill children from 2007 to 2012.

METHODS:

In this cohort study, we included NICUs and PICUs located in hospitals reporting data to the Centers for Disease Control and Prevention’s National Healthcare Safety Network for central line–associated bloodstream infections (CLABSIs), ventilator-associated pneumonias, and catheter-associated urinary tract infections. We used a time-series design to evaluate changes in HAI rates.

RESULTS:

A total of 173 US hospitals provided data from NICUs, and 64 provided data from PICUs. From 2007 to 2012, rates of CLABSIs decreased in NICUs from 4.9 to 1.5 per 1000 central-line days (incidence rate ratio (IRR) per quarter = 0.96, 95% confidence interval 0.94–0.97) and in PICUs from 4.7 to 1.0 per 1000 central-line days (IRR per quarter = 0.96 [0.94–0.98]). Rates of ventilator-associated pneumonias decreased in NICUs from 1.6 to 0.6 per 1000 ventilator days (IRR per quarter = 0.97 [0.93–0.99]) and PICUs from 1.9 to 0.7 per 1000 ventilator-days (IRR per quarter = 0.95 [0.92–0.98]). Rates of catheter-associated urinary tract infections did not change significantly in PICUs.

CONCLUSIONS:

Between 2007 and 2012 there were substantial reductions in HAIs among hospitalized neonates and children.
Surgical possibilities in the treatment of advanced and locally recurrent breast cancers
Authors: Mátrai Zoltán , Rényi Vámos Ferenc
Published: September 2014

Stage IV breast cancer is an incurable but treatable condition. Therapy of distant metastatic disease consists primarily of systemic and symptomatic treatments, while the role of surgery is subordinate. Conventional medical treatments result in 18–24 months average overall survival, and about 5–20% 5-year overall survival. However, it seems that in selected cases with solitary or oligometastases, mainly in those which respond well to drug therapy, the aggressive surgical removal of both the primary tumour and visceral metastases results in a survival advantage. After accurate evaluation of the patients, the indication for surgical treatment should be established through a biological and multidisciplinary approach. Other possible indications for surgical treatment are ulceration, bleeding, hygienic conditions undignified of human life, central nervous system metastases, acute neurological disorders, hydro- and pneumothorax greatly reducing respiratory surface and impending fractures. Surgical procedures include simple pleural drainage, minimal invasive techniques, large body cavity surgeries, extensive resection of soft tissue and chest wall due to the primary tumor, and plastic surgical reconstruction as well. Scientific assessment of the oncological value of surgical oncological interventions in stage IV. breast cancer require further multicentric prospective comparative studies. The present paper provides a broad review of the literature on surgical interventions and results in patients with breast cancer and remote metastases, and the surgical options of locally recurrent tumours. Orv. Hetil., 2014, 155(37), 1461–1468.
The secretory mechanism of the muscular system and its role in the metabolism and utilization of energy
Authors: Halmos Tamás , Suba Ilona
Published: September 2014

It is well-known for a long-time, that intensive exercise is favourable for many metabolic parameters. Up-till now the exact mechanism has not been clarified. Recently it has turned out, that the muscular system is an extended endocrine organ, which, during contraction, secretes many hundred peptides, so called adipomyokines into the blood stream. Many of them improve glucose-utilization of the muscular system, and insulin-sensitivity, via endocrine, paracrine, or autocrine pathways. Worldwide intensive research takes place to clear up the exact pathomechanism of these processes. It came to light: 1. The newly discovered adipomyokine, irisin induces “browning” of beige precursor fat-cells, which are present in white adipose tissue. The developed beige adipose tissue by this way disposes with the advantegous properties of the brown adipose tissue. Taking together these facts, irisin might be a therapeutic choice in treating certain diseases, caused by inactive life-style. 2. Therapeutic application of brown adipose tissue in obesity, metabolic syndrome, and type 2 diabetes seems to be successful. This mechanism is based on removal of unnecessary calories via thermogenesis. 3. The role of myostatin, which is also produced by muscle contraction, is contradictory. It is not clear, why does the muscle system produce damaging product for the metabolism. On the other hand, inhibition of myostatin might be a therapeutic option. It is still questionnable, whether the other hundreds of myokines could possess practicable roles on glucose, lipid, insulin secretion/effects. At present one can establish, that regular exercise is essential for the everyday practise, in order to optimise quality of life. Orv. Hetil., 2014, 155(37), 1469–1477.
Microbiota–host symbiosis in the pathophysiology and treatment of irritable bowel, irritable eye and irritable mind syndrome
Authors: Fehér János , Kovács Illés , Pacella Elena , Radák Zsolt
Published: September 2014

Accumulating clinical evidence supports co-morbidity of irritable bowel, irritable eye and irritable mind symptoms. Furthermore, perturbation of the microbiota–host symbiosis (dysbiosis) is considered a common pathogenic mechanism connecting gastrointestinal, ocular and neuropsychiatric symptoms. Consequently, maintaining or restoring microbiota–host symbiosis represents a new approach to treat these symptoms or to prevent their relapses. Current treatment approach assigned a primary role to live probiotics alone or in combination with prebiotics to enhance colonization of beneficial bacteria and to strengthen the symbiosis. However, several papers showed major benefits of heat-killed probiotics as compared to their live counterparts on both intestinal and systemic symptoms. Recently, in addition to killing probiotics, in a proof of concept study lysates (fragments) of probiotics in combination with vitamins A, B, D and omega 3 fatty acids were successfully tested. These findings suggested a conceptual change in the approach addressed to both the microbiota and host as targets for intervention. Orv. Hetil., 2014, 155(37), 1454–1460.
Chronic obstructive pulmonary disease: a cardiologist’s point of view
Authors: Faludi Réka
Published: September 2014

Chronic obstructive pulmonary disease is often associated with cardiovascular diseases, such as pulmonary hypertension, ischemic heart disease, arrhythmias or heart failure. These co-morbidities may cause diagnostic or therapeutic difficulties and significantly worsen the morbidity and mortality of patients with chronic obstructive pulmonary disease. In this work the author reviews special considerations for the treatment of patients with chronic obstructive pulmonary disease who have cardiovascular co-morbidities. Orv. Hetil., 2014, 155(37), 1480–1484.
Growth of Reduced Graphene Oxide
Authors: Huang Jingfeng , Chen Hu , Fam Derrick , Faulkner Steve H. , Niu Wenbin , Larisika Melanie , Nowak Christoph , Nimmo Myra A. , Yoong Tok Alfred Iing
Published: September 2014

Reduced graphene oxide (RGO) has the advantage of an aqueous and industrial-scalable production route. However, one of the main limitations that prevent the use of RGO in electronics is the high electrical resistance deviation between fabricated chips. In this article, we present the novel growth of RGO which can bridge the gaps in-between existing flakes and thus reduce the electrical resistance standard deviation from 80.5 % to 16.5 %. The average resistivity of the treated RGO of ∼ 3.8 nm thickness was 200 Ω/square. The study uses an atmospheric-pressure chemical vapour deposition (CVD) system with hydrogen and argon gas bubbling through ethanol before entering the furnace. With a treatment of 2 hours, 100 % of the silicon dioxide substrate was covered with RGO from an initial 65 % coverage. This technology could enable large-scale application of RGO use in practical electronic devices.
Buddhist Aesthetics?
Authors: Gombrich Richard
Published: September 2014

The Pali canon shows a largely negative view of visual art. In ancient Indian culture, beauty is associated with sexual attraction, and has an erotic overtone. Concern with beauty conflicts with the Buddhist ideal of detachment from worldly pleasures. On the other hand Buddhists have created wonderful works of art, and monks can be painters or dancers. Pictures and performances are made as expressions of devotion, and as means of acquiring merit, and most importantly to convey a Buddhist message.
Introduction of the dengue virus type 4 in the State of Mato Grosso do Sul, Brazil
Authors: Bertolacci-Rocha Lívia Garcia , Cunha Rivaldo Venâncio da , Lichs Gislene Garcia de Castro , Fabbro Márcia Maria Ferrairo Janini Dal , Motta-Castro Ana Rita Coimbra
Published: September 2014

We report on the first isolation of dengue virus serotype 4 (DENV-4) in the State of Mato Grosso do Sul, Brazil, in February, 2012. The cases were isolated in the city of Campo Grande, the state capital, and presented the classic signs and symptoms of dengue fever. DENV-4 was primarily identified through viral isolation in C6/36 clone lineage of Aedes albopictus cells; followed by indirect immunofluorescence, using type-specific monoclonal antibodies. The results were subsequently confirmed by Nested RT-PCR tests. The first description of the introduction of DENV-4 in a state whose population is susceptible to this serotype and the circulation of three other serotypes in the area is cause for concern due to the increased possibility of severe and lethal cases of the disease, and of huge epidemics.
Classificação orientada a objeto de imagens de sensoriamento remoto em estudos epidemiológicos sobre leishmaniose visceral em área urbana
Authors: Almeida Andréa Sobral de , Werneck Guilherme Loureiro , Resendes Ana Paula da Costa
Published: September 2014

Neste estudo, explorou-se o uso da classificação orientada a objeto de imagens de sensoriamento remoto em estudos epidemiológicos sobre leishmaniose visceral (LV) em áreas urbanas. A classificação orientada a objeto foi aplicada a cenas Landsat 5 TM da cidade de Teresina, Piauí, Brasil, para obtenção de informações ambientais e temperatura. Para o período de 1993-1996, a taxa de incidência de LV nos setores censitários da cidade foi positivamente correlacionada com a área do setor censitário coberta por vegetação densa, rasteira e solo exposto e negativamente com a área coberta por água e áreas densamente ocupadas. No período de 2001-2006, foram encontradas correlações positivas com vegetação densa, rasteira, solo exposto e áreas densamente ocupadas e negativas com áreas urbanas com alguma vegetação. A temperatura da superfície terrestre foi negativamente associada à incidência de LV nos dois períodos. A classificação orientada a objeto pode ser útil para caracterizar paisagens associadas à ocorrência da LV em áreas urbanas e delimitar áreas de risco para definição de prioridades na implementação de intervenções.
Eficiência dos estados brasileiros e do Distrito Federal no sistema público de transplante renal: uma análise usando método DEA (Análise Envoltória de Dados) e índice de Malmquist
Authors: Costa Cassia Kely Favoretto , Balbinotto Neto Giácomo , Sampaio Luciano Menezes Bezerra
Published: September 2014

O objetivo foi avaliar a eficiência dos estados brasileiros e do Distrito Federal no sistema público de transplante renal e a mudança de produtividade deles entre 2006 e 2011. Utilizou-se a Análise Envoltória de Dados (DEA) baseada em folgas e o índice de Malmquist com folgas. Os inputs usados foram os gastos dos serviços hospitalares e dos profissionais no sistema. Como output, o número de transplantes renais realizados por cada estado. Existe uma discrepância significativa em relação à captação e ao número de transplantes renais entre os estados. Evidencia-se uma ineficiência nesse sistema, que poder ser causada por sua gestão inadequada; não seguimento de regras nacionais; comissões intra-hospitalares não ativas e equipes hospitalares sobrecarregadas. As mudanças institucionais promovidas pelo Ministério da Saúde (aperfeiçoamento e padronização dos processos) não geraram aumento de produtividade na maioria dos estados nesse período.
Dimensões do coletivo na atividade de trabalho Dos motoboys
Authors: Moraes Thiago Drumond , Athayde Milton Raimundo Cidreira de
Published: September 2014

Políticas públicas brasileiras procuram reduzir a gravidade do quadro de acidentes de trabalho dos motoboys, priorizando dimensões individuais da pilotagem. Seus resultados são limitados por não contemplarem satisfatoriamente dimensões coletivas do trabalho e seus efeitos na profissão. Ademais, há carência de pesquisas neste campo. Para colaborar neste movimento de compreender↔transformar, objetivou-se verificar como o coletivo profissional vem se desenvolvendo no meio profissional dos motoboys. Orientada pela Ergologia, na pesquisa mobilizou-se vertentes clínicas do trabalho: Psicodinâmica do Trabalho e Clínica da Atividade. Observou-se a existência de coletivo profissional em formação, verificada por meio de saberes práticos, sistemas defensivos, linguagem profissional, valores e regras de ofício, que começam a ser elaborados e partilhados por esses trabalhadores. Porém, verificou-se que individualismo e baixa solidariedade entre pares vêm fragilizando esse coletivo, reduzindo sua capacidade de resposta às condições degradantes de trabalho. Entende-se incontornável seu fortalecimento no caminho do exercício profissional mais seguro.
DIAGNÓSTICO ETIOLÓGICO DE CATARROS GENITAIS EM VACAS LEITERAS
Authors: Cordeiro João Lari Félix , Neves Jairo Pereira , Albuquerque Antonio Jorge Dreon de , Badke Manoel Renato Teles
Published: September 2014

Cem vacas leiteras da região do Vale do Itajaí, de Santa Catarina, foram agrupadas, através do exame ginecológico, em quatro categorias, para um estudo bacteriológico dos catarros genitais inespecíficos. Os grupos compostos de 25 vacas, em fase pós-puerperal, foram assim caracterizados: A - sem alteração; B - catarro genital do primeiro grau; C - catarro genital de segundo grau; D - catarro genital de terceiro grau. O exame bacteriológico das secreções cérvico-uterinas demonstrou que ocorreu crescimento bacteriano em 57 vacas, das quais 46 com manifestação clínica de catarro genital. Os microrganismos mais freqüentemente isolados foram Staphylococcus epidermidis, Streptococcus beta - hemolítico, Bacillus sp., Escherichia coli, Actinomyces pyogenes, Serratia odorífera, Proteus mirabilis e Candida sp. Considerando que foi detectado crescimento bacteriano nos quatro grupos de vacas, conclui-se que não existe relação entre este crescimento e a existência de catarros genitais.
DESCRIÇÃO DE Cucullanus patoi sp. n. (NEMATODA, CUCULLANIDAE) DE PINTADO Pimelodus maculatus LACÉPEDE, 1803 (PISCES), DO LAGO DO GUAÍBA, RS, BRASIL
Authors: Fortes Elinor , Hoffmann Rita Pato , Sarmento Telma Maria
Published: September 2014

Uma nova espécie de nematódeo, Cucullanus patoi sp. n. é descrita no intestino do pintado (Pimelodus maculatus) do Lago do Guaíba, RS.
Performance of the probability distribution models applied to heavy rainfall daily events
Authors: Marques Rosângela Francisca de Paula Vitor , Mello Carlos Rogério de , Silva Antônio Marciano da , Franco Camila Silva , Oliveira Alisson Souza de
Published: September 2014

Probabilistic studies of hydrological variables, such as heavy rainfall daily events, constitute an important tool to support the planning and management of water resources, especially for the design of hydraulic structures and erosive rainfall potential. In this context, we aimed to analyze the performance of three probability distribution models (GEV, Gumbel and Gamma two parameter), whose parameters were adjusted by the Moments Method (MM), Maximum Likelihood (ML) and L - Moments (LM). These models were adjusted to the frequencies from long-term of maximum daily rainfall of 8 rain gauges located in Minas Gerais state. To indicate and discuss the performance of the probability distribution models, it was applied, firstly, the non-parametric Filliben test, and in addition, when differences were unidentified, Anderson-Darlling and Chi-Squared tests were also applied. The Gumbel probability distribution model showed a better adjustment for 87.5% of the cases. Among the assessed probability distribution models, GEV fitted by LM method has been adequate for all studied rain gauges and can be recommended. Considering the number of adequate cases, MM and LM methods had better performance than ML method, presenting, respectively, 83% and 79.2% of adequate cases.
Fazer viver e deixar morrer: a velhice na era do biopoder
Authors: Matos Robson Kleber de Souza , Vieira Luciana Leila Fontes
Published: September 2014

O presente artigo objetiva investigar a forma pela qual o biopoder incide sobre a construção da velhice na atualidade, principalmente, através do discurso médico-cientifico. Para tanto, a partir da obra foucaultiana, investigamos as origens, as características e as especificidades do poder disciplinar, da biopolítica e do biopoder, interrogando as suas incidências e as suas implicações em relação à posição de exclusão e de marginalização social do idoso. Espera-se, assim, repensar a posição do idoso e fomentar possibilidades para se construir uma nova imagem para essa parcela da população.
Ocorrência de equídeos soropositivos para os vírus das encefalomielites e anemia infecciosa no Estado de Mato Grosso
Authors: Melo R.M. , Cavalcanti R.C. , Villalobos E.M.C. , Cunha E.M.S. , Lara M.C.C.S.H. , Aguiar D.M.
Published: September 2014

O presente trabalho determinou a ocorrência de equídeos com sorologia positiva para os vírus das encefalomielites virais dos tipos Leste (EEL), Oeste (EEO) e Venezuelana (EEV) e Anemia Infecciosa (AIE) nos biomas Amazônico, Pantaneiro e Cerrado do Estado de Mato Grosso. A detecção de anticorpos para AIE foi realizada em 886 soros pela prova de Imunodifusão em Gel de Ágar (IDGA), enquanto que para EEL, EEO e EEV foi realizada em 473 soros pela Microtécnica de Soroneutra-lização viral em culturas de células VERO. Para AIE, 46 (5,1%) equídeos foram positivos, não sendo observados animais positivos da região amazônica e a maior frequência ocorrendo no ambiente do pantanal com 36,6% de animais positivos (P < 0,05). Para as encefalites virais, foram detectados 168 (35,5%) equídeos positivos para EEL e 31 (6,5%) para EEV. Não houve soros positivos para EEO. As maiores frequências de animais positivos para EEL foram observadas nos ambientes pantaneiro e amazônico com 45,8% e 62,0%, respectivamente (P < 0,05). Os três biomas estudados apresentaram ocorrência similar (P > 0.05) de animais positivos para EEV, com 4,1%, 6,4% e 10,3% para o pantanal, cerrado e amazônia, respectivamente. Embora não apresentando equídeos reagente ao vírus da AIE na região amazônica, a presença de positivos em Mato Grosso encontra-se dentro do relatado no Brasil. O comportamento diferenciado do vírus da EEL e EEV nos três ecossistemas estudados reforça a presença de animais reservatórios, condições ambientais e climáticas que favorecem a proliferação de vetores que propiciam a infecção pelos vírus no Estado de Mato Grosso.
Avaliação microbiológica e físico-química de linguiça toscana no Município de Mossoró, RN
Authors: Bezerra M.V.P. , Abrantes M.R. , Silvestre M.K.S. , Sousa E.S. , Rocha M.O.C. , Faustino J.G. , Silva J.B.A.
Published: September 2014

Com o objetivo de avaliar a qualidade microbiológica e físico-química da linguiça toscana comercializada no Município de Mossoró, RN, foram analisadas 28 amostras de seis supermercados, verificando-se o Número Mais Provável (NMP) de coliformes termotolerantes, Salmonella spp. e bactérias psicrotróficas, umidade, pH e atividade de água. Todas as amostras estavam dentro do padrão vigente que estabelece um limite máximo de 5 x 10³ NMP/g-1 para coliformes termotole-rantes conforme a ANVISA. Na contagem de bactérias psicrotróficas houve uma variação de 2,9 x 10¹ a 1,31 x 10(4) UFC/g-1. Das 28 amostras pesquisadas quanto a presença de Salmonella spp., em cinco verificou-se a presença deste micro-organismo em 25 g. Para umidade, todas as amostras encontravam-se dentro da legislação estabelecida (< 70%) e para atividade de água os limites variaram de 0,772 a 0,809. Os valores de pH das amostras estavam entre 5,7 e 6,2. Apesar das amostras analisadas estarem dentro do estabelecido pela legislação brasileira, faz necessária a aplicação de boas práticas, visto que a contaminação por micro-organismos psicrotróficos e Salmonella foi significativa, podendo diminuir a vida de prateleira do produto e causar danos a saúde pública.
Análise organizacional de destinos turísticos com base nos conceitos de mudança, de incerteza e na Teoria do Caos: estudo dos exemplos de Gramado e Canela, na serra gaúcha
Authors: Tomazzoni Edegar Luis , Dorion Eric , Zottis Alexandra
Published: September 2014

As teorias da mudança e do caos proporcionam visão do conjunto de relações, aspectos e implicações do turismo, com base nas incertezas e instabilidades ambientais e de mercado. A maioria dos modelos de análise, planejamento e gestão do turismo ainda é limitada, em razão do seu caráter linear e unidimensional. O objetivo da teoria do caos é fornecer explicações dos fenômenos, não é fazer previsões, pois é impossível prever o futuro a longo prazo. As estratégias de gestão geram novas fontes de incerteza, pois a realidade não pode ser completamente representada por modelos. Ter consciência desses fatos significa, entretanto, considerar o campo de múltiplas possibilidades e oportunidades da mudança e do caos na gestão do desenvolvimento do turismo. Essas idéias são aplicadas à análise das experiências de dois dos principais municípios turísticos do Brasil, Gramado e Canela, localizados na Região das Hortênsias, Serra Gaúcha.
A mobilidade como novo capital simbólico nas organizações ou sejamos nômades?
Authors: Freitas Maria Ester de
Published: September 2014

O objetivo deste artigo, de natureza exploratória, é o de analisar a mobilidade como um novo capital simbólico no mundo organizacional. Argumentamos três questõeschave: a) a de que a mobilidade já é uma necessidade sócioorganizacional; b) a de que a transformação ideológica dessa necessidade em virtude legitima a mobilidade como um novo capital; e c) a de que a circulação mundial de profissionais, por meio de processos de expatriação, e a de empresas, a partir de processos de relocalização, fusões e aquisições, traduzem um novo tipo de nomadismo que reforça a mobilidade como um valor desejável. Em virtude da ausênciade bibliografia específica sobre o tema no universo organizacional, construímos ao longo do texto alguns conceitos, dentre eles o de mobilidade. Esta se refere à capacidade, à disposição e ao desejo que um individuo tem de mudar de país para interagir com diferenças em relação à sua cultura, à sua profissão, aos seus saberes e ao seu cargo. O conceito de capital simbólico foi tomado de empréstimo de Bourdieu, que desenvolveu e consolidou, progressivamente, elementos conceituais para uma teoria da ação social(1972, 1980 e 1994) e, junto com Passeron (1964 e 1970), analisou mecanismos de reprodução social.
A new modal pushover analysis approach for soil–structure interaction
Authors: Halabian Amir M. , Zafarani Mohammad M.
Published: September 2014

Soil–structure interaction has been taken into account in performance-based seismic analysis of flexibly supported single-degree-of-freedom systems, but there has been less research for multiple-degrees-of-freedom structures. In a new complex modal pushover analysis developed in this study, the seismic demand for each mode is determined by regular pushover analysis method using modified modal inertia force distributions. Combining all modal demands then leads to the estimation of seismic demands of the soil–structure system. A set of generic frame models representing low-rise, mid-rise and high-rise structures was developed. The foundation flexibility was considered using a substructuring method and the soil–structure systems were subjected to a number of far-field and near-fault ground motions. The results indicated that the foundation flexibility could significantly change the response of the system and neglecting this phenomenon might lead to erroneous conclusions in the prediction of seismic performance of flexibly supported reinforced concrete frame structures.
Annular Pressure Build Up (APB) Analysis-Optimization of Fluid Rheology
Authors: Osgouei R. Ettehadi , Miska S. Z. , Ozbayoglu M. E. , Takach N. E. , Coe D.. , Chen D. C.
Published: September 2014

Annular pressure build up (APB) is an important problem in the area of well design. Different solutions have been proposed to mitigate APB, including vacuum-insulated tubing, silicate foam wellbore insulation techniques, and insulating with completion (packer) fluids. However, proposed solutions that include the optimization of annular fluid rheology of drilling fluids trapped in the outer annuli need further investigation.

Convective and conductive heat transfer through fluids placed between the casing strings is a driving force for increasing annular pressure. This study explains how to design and optimize the rheological and thermal properties of drilling fluid to provide a sustainable and reliable insulating performance. The objectives of this study are 1) to develop a better insight of APB in the annulus of casing and 2) to experimentally measure and 3) analytically model the effect of different parameters, such as rheological and thermal properties, on the insulating performance of drilling fluid trapped in annular spaces.

By combining the theory of sedimentation and the model proposed for free convective heat transfer of Yield Power Law fluids, a stepwise guideline is proposed to estimate the Nusselt number and thermal conductivity coefficient of annular fluids. A computer code to perform this procedure has been developed. Additionally, a unique experimental apparatus was designed and constructed to investigate the insulating performance of drilling fluids.

Experimental observation and model results indicate that compressive yield stress, density difference between the solid and liquid phases of a drilling fluid, solid particle size and annular space geometry, are four important factors that determine sedimentation rate. These criteria can be used to characterize YPL annular fluid properties to minimize sedimentation rate and consequently to reduce free convective flow. The magnitude of the convective heat transfer coefficient is affected by the shear yield stress and density of annular fluid, by the flow behavior index (m), consistency index (k), conductivity coefficient and specific heat of the YPL fluid, and by annular space clearance. This conclusion can be used to quantitatively analyze the reliability and sustainability of the insulating performance of drilling fluids.

The sedimentation profile, shear yield stress distribution and effective conductivity coefficient profile as functions of time and depth, as well as the Nusselt number, Nu, as a function of temperature difference in the radial direction can be estimated by the introduced guideline. The most important achievement is that the developed guideline can be used as a design tool in offshore drilling and completion operations to mitigate APB. A practical benefit of this study is demonstrated by the application of its findings in an illustrative example.
Improved Sand-Screen Design for Multi-Joint Flow Control
Authors: Hailey Travis , Cunningham Scott , Novelen Ryan , Kang James
Published: September 2014

A new sand screen design that enables collection and control of production flow from multiple sand-screen joints has been developed; the control in this design is in the form of a sliding-sleeve circulating device that is at a single point and enables flow from multiple joints. This type of functionality was developed previously for use in multiple-zone frac- or gravel-packs as a means of helping to control flows and pressures more efficiently in zones other than the one being packed. However, these early designs were less efficient in use of available geometry than the new design, which uses, 1) tall wire ribs of a wire-wrapped structure to create an annular flow space, and 2) an innovative crimping technology that uses plastic deformation of metal components to connect the annular flow space across connections between sand-screen joints during rig assembly.

Although the initial use of the new screen design was planned to provide an improvement to existing multi-zone packing systems (the new screens are already being planned for use in two deep-water lower tertiary projects in the Gulf of Mexico), alternative uses are now being envisioned for the design. Future uses may be as stand-alone or gravel-packed screens in long (probably horizontal) intervals, where a single circulating sleeve can control a longer portion of the interval. Another improvement being considered is the incorporation of passive inflow-control device (ICDs or AICDs) functionality into the single flow points for multiple screens.

Additionally, with minor modification, it is anticipated that the new screen design will be conducive to installing tracer materials in the channels between ribs of the annular flow space.
Lost Circulation Materials Capability of Sealing Wide Fractures
Authors: Alsaba Mortadha , Nygaard Runar , Saasen Arild , Nes Olav-Magnar
Published: September 2014

Lost circulation prevention or mitigation is a major challenge while drilling. Conventional lost circulation materials (LCM) are often implemented to prevent/cure seepage or partial losses. When it comes to severe losses, often caused by larger fracture sizes, special treatments are being applied. Curing severe losses with specialized treatments requires more time because some treatments can't be applied in the presence of downhole tools, where special equipment and procedures are required. In addition, polymer and cement treatments require time to be activated or cured after being pumped.

Evaluating the performance of LCM and their effectiveness in sealing wide fractures is required in conjunction with an optimized LCM combination to ensure their ability in curing losses. This paper presents investigations about the possibility of sealing relatively large fracture using conventional LCM instead of the other approaches such as cement or hydratable LCM pills. Two specifically developed apparatuses were used to optimize LCM combination and investigate their ability in sealing wide fractures at different pressures. A set of tapered slots that simulate sealable fracture widths with different fracture aperture (2.5 – 5 mm) and tip sizes (1-2 mm) were used in this study.

A total of 160 tests were conducted to optimize LCM combinations and concentrations in addition to 30 tests to evaluate the integrity of the seal formed under elevated pressures with apparatus capability of up to 10,000 psi (69 MPa) fracture differential pressure. The effects of varying LCM's type, concentration, particle size distribution and fracture width were studied with respect to differential pressure and fluid loss. The results showed that LCM's that have irregularity in particles shapes and a degree of deformability such as nut shells are capable of sealing wide fractures when used individually or in combination with other LCM's. In addition, a strong relationship between fluid loss values and the seal integrity was observed, i.e. lower fluid loss, gave higher sealing efficiency.

There is a good potential for conventional LCM's to be reconsidered as a corrective approach for partial or severe losses when the proper LCM's size, type and concentration are selected for a wider range of fracture widths. Curing losses using conventional LCM's for a wider range of fractures widths is advantageous since it can cut time and cost compared to current practices.
A Novel Approach in Locating Single Loss Zone during Deepwater Drilling with Distributed Temperature Measurement
Authors: Chen Yuanhang , Yu Mengjiao , Miska Stefan Z. , Ozbayoglu Evren M. , Takach Nicholas
Published: September 2014

One of the major concerns when drilling deepwater wells is fluid loss since the fracture gradients are typically lower than their onshore counterparts. Failure to minimize the fluid loss can significantly increase the cost of drilling, and even lead to abandonment of the well. Successful management of lost circulation should incorporate accurate estimation of loss zone location, followed by corresponding lost circulation control procedures.

This paper presents an innovative way to estimate the location of mud loss by interpreting distributed temperature measurement which is facilitated by a recently developed drilling microchip technology. Firstly, a transient wellbore thermal model is presented to predict the effect of mud loss on the change in circulating mud temperature profile for tubular fluids. The model is developed based on heat balance equations with variable local flow rates along the wellbore due to the mud loss. The effects of heat transfer above the seabed between riser and the drilling muds are included. Downward shifts in the temperature curves are noted in both the drillpipe and annulus. With distributed temperature measurement data, the derivative of annulus temperature with respect to depth can be used to effectively identify the location of the loss zone. A case study has been conducted to identify the location of a loss zone in a deepwater well. According to the results, a jump in the derivative coincides with the location of loss and is sufficiently significant in magnitude to be identified. The seawater-riser heat transfer has minimum effect on the loss zone prediction; furthermore, the effect of the same amount of loss is more conspicuous if the loss occurs at a shallower depth, in which case the loss zone can be more reliably located.
Investigating the Impact of the "Tool Joint Effect" on Equivalent Circulating Density in Deep-Water Wells
Authors: Vajargah Ali Karimi , Fard Fardis Najafi , Parsi Mazdak , Hoxha Besmir Buranaj
Published: September 2014

Precise prediction of Equivalent Circulating Density (ECD) is one of the most important challenges during drilling operations. This becomes more vital in deep-water offshore wells in which formation pressure is very close to the fracture pressure. In addition, techniques such as Managed Pressure Drilling (MPD) rely on the precise estimation of frictional pressure losses.

Although many theoretical and experimental studies have been conducted on fluid flow through pipes and annuli to predict the pressure losses, majority of them undermine or simply ignore the effect of tool joints. A few studies that take the effect of tool joints into account indicate that it can have significant effect on pressure loss. Therefore, there is a strong need to determine the amount of additional pressure loss caused by the tool joints.

This paper presents a Computational Fluid Dynamics (CFD) approach to investigate the effect of tool joint on annular pressure losses. The utilized software package in this simulation study uses Finite Volume methods to solve the problem. The effects of important parameters such as flow rate, mud type, mud weight and mesh size are investigated. The pressure loss in the annuli, with and without tool joint, is obtained and additional pressure loss due to presence of tool joint is calculated accordingly.

Simulation results show that the ratio of annular pressure loss with tool joints to the pressure loss without tool joints (α) strongly depends on the flow regime. In Laminar flow, this ratio remains relatively constant, regardless of the type of the drilling fluid. In turbulent flow, it increases rapidly with increasing Reynolds number and can be precisely estimated by the proposed correlation. It has been found that in deep offshore wells and high range of operational flow rate, the additional pressure loss due to tool joints can be as high as 30% of the total frictional pressure loss and must be taken into consideration during ECD calculations.
Finite Element Analysis of Casing Drilling Smearing Effect
Authors: Kiran R.. , Salehi S.. , Karimi M..
Published: September 2014

Casing while Drilling (CwD) is a new drilling method where the well is drilled and cased simultaneously. Previous field operations of CwD have shown a decrease in drilling non-productive time as well as improvement in controlling lost circulation and wellbore stability. Although advantages of this technology are well noted in the literature, the mechanisms of improvements were not studied comprehensively. In order to study these mechanisms, one has to understand the formation properties, fluid hydraulics, casing dynamics, and how CwD helps in better hydraulic control and results in strengthening effects. In the previous research works, the factors that were widely discussed and results obtained were related to formation properties. However, while considering the stresses in the wellbore, mechanical factors such as the RPM and contact of casing at different positions in wellbore were usually neglected. In furtherance to this study, the importance of plastering mechanism cannot be ignored. This work includes a new insight towards the underlying mechanism of casing-wellbore contact and changes in the near wellbore stresses while casing rotation. The main objective of this study is to investigate the hypothesis of the increase in hoop stress when the casing contacts wellbore with regard to the formation stresses orientations. To accomplish this objective, finite-element analysis has been conducted to simulate several CwD scenarios. The classical equations used to obtain the wellbore stresses include parameters like the far-field stresses, pore pressure, and wellbore geometry. These equations do not consider the effect of casing pipe contact and eccentricity; therefore finite element simulations can be very helpful to investigate these effects. Casing-wellbore contact in both maximum and minimum in-situ stress directions are considered in this study as well as changing contact length. The study of different cases shows the variation of hoop stress, which can be beneficial if properly implemented in CwD operations.
Profiling Drilling Fluid’s Invasion Using Scanning Electron Microscopy: Implications for Bridging and Wellbore Strengthening Effects
Authors: Salehi Saeed , Hussmann Stefanie , Karimi M.. , Ezeakacha Chinedum , Tavanaei Amirhossien
Published: September 2014

Wellbore stability issues are continually plaguing the industry and it is important to understand the mud properties that contribute to these issues. The effects of mud cake build up and filtration with time aids the understanding of formation damage and wellbore stability. The increase of drilling in high temperature and pressure zones (HTHP) necessitates studies that can predict filtrate invasion, and particle bridging. The most common hydraulically challenged zones are: depleted sands or intervals with very low pore pressure and fracture pressure, wellbore ballooning zones encountered in deep water drilling where surge and swab pressures could be a serious challenge, and complete lost circulation/no return zones.

Filtrate invasion and mud cake build up can be considered as primary factors controlling wellbore stability while drilling. Decreasing the near wellbore permeability by forming an ultra low permeability mud cake can strengthen the wellbore and mitigate further lost circulation problems. Very few studies have investigated filtration and filter cake build up under HPHT situations where the effect of different mud particles and bridging solids can be analyzed.

This paper focuses on experimental methods to investigate the effects of particle bridging, filtrate invasion and permeability on some common water based muds used by the industry. The methodology in this paper is based on using high temperature and pressure (HTHP) filtration tests at different time steps on sandstone cores of 50 mD and 750 mD fitted into Particle Plugging Test (PPT) aparatus. The Scanning Electron Microscope (SEM) and elemental mapping was used to characterize filter cake and further investigating the particles invasion in the core samples. Finally, mud cake permeability of the samples was calculated using analytical models from litreture.
Study of Casing Annulus Pressure for Deepwater Drilling and Completions
Authors: Liu Baosheng , Yang Jin , Zhou Bo , Yan De , Tian Ruirui , Liu Zhengli , Luo Junfeng , Huang Xiaolong
Published: September 2014

Casing collapse and fracture may be caused by the rise of casing annulus temperature and pressure in the initial stage of production and testing of deepwater wells. Based on the casing program and wellbore heat transfer process, a pressure calculation model for casing annulus was established, which provides basis for annulus pressure control.

Fluid trapped in the annulus of subsea wells can cause casing strings to fail. This condition occurs when casing annuli attain a closed-volume circumstance (when a well is cased, cemented, and head seals are set). During production, the heat transfer of the produced fluids to the casing strings causes the trapped fluid to increase in pressure. This condition is magnified in deepwater because annular fluids are cooler due to the cold deepwater environment.

With the annulus between testing string and production casing as an example, a casing annulus temperature calculation method was derived according to the principle of conservation of energy and wellbore heat transfer analysis. The casing annulus pressure prediction model was established for typical deepwater wells according to the volume change of casing annulus fluid with temperature and pressure, and in combination of the casing annulus PVT equation and annulus temperature equation.

The casing annulus temperature and pressure calculation methods were successfully applied in the casing annulus temperature and pressure management operation in deepwater wells in West Africa, and the predicted temperature and pressure were compared with the actual ones, which indicates that casing annulus temperature and pressure prediction methods have good accuracy.
Automated Well Control Decision-Making during Managed Pressure Drilling Operations
Authors: Vajargah Ali Karimi , Hoxha Besmir Buranaj , van Oort Eric
Published: September 2014

Blow-out prevention and formation gas/fluid influx control is a major concern in any drilling operation. In conventional drilling, the only widely accepted response to a gas influx is to shut the well in on the BOPs. New Managed Pressure Drilling (MPD) technology using the constant bottom-hole pressure (CBHP) technique allows for circulating small and medium-sized influxes out without the need to shut in the well, either by increasing casing back-pressure and/or adjusting pump flow rate. Evident benefits include a faster response to the influx (with clear safety benefits) and a considerable time and cost savings compared to the conventional approach.

Unfortunately, there is currently no method available to decide upon the best MPD-CBHP response during an influx, because such a response depends on many parameters, such as Maximum Allowable Surface Pressure (MASP), wellbore geometry, fracture pressure of any weak zones exposed in open hole, type of drilling fluid, influx size, etc. To remedy this situation, we present a fast and accurate decision-making method that overcomes the traditional difficulties and automatically selects a best well control response. The method incorporates a transient multi-phase model based on mass, energy and momentum conservation. A sophisticated numerical simulator was developed for this purpose. Comparing the actual well response with simulated results during an influx event and following the proposed algorithm allows the best response to be taken in a quick, convenient, and accurate manner. Moreover, the approach lends itself well to fully automated control.

Here, we describe the new method and its validation using available two-phase experimental data for annular air-mud flow for a wide range of flow rates and flow regimes. We believe that the method provides a powerful new decision-making and design tool in MPD operations that ensures delivery of safer wells with lower non-productive time and associated trouble cost spent on well control operations.