bluuebunny/crossref_metadata_2025 huggingface dataset:
Diseño de un amplificador operacional de transconductancia aplicando técnicas de optimización multiobjetivo
Authors: Pereira-Arroyo Roberto , Molina-Robles Roberto , Chacón-Rodríguez Alfonso
Published: November 2015

En este trabajo, el problema en cuestión consiste en el dimensionamiento de un Amplificador Operacional de Transconductancia (OTA). El frente de Pareto se introduce como un concepto útil de análisis con el fin de explorar el espacio de diseño de este tipo de circuitos analógicos. Se emplea un algoritmo genético (GA) para detectar automáticamente este frente, en un proceso que de manera eficiente encuentra parametrizaciones óptimas y sus valores correspondientes en un espacio agregado de aptitudes. Ya que el problema es tratado como una tarea de optimización multiobjetivo, las diferentes medidas del amplificador como la transconductancia, razón de cambio de salida, el rango lineal y la capacitancia de entrada se utilizan como funciones de aptitud. Por último, se presentan los resultados de simulación, utilizando una tecnología CMOS estándar de 0,5μm.
Lineamientos para la manufactura de partes de alta precisión
Authors: Robles-Obando Natalia
Published: November 2015

La asignación de tolerancias para las dimensiones de las partes tiene un efecto importante tanto en el costo de la manufactura como en su calidad. Una manufactura muy precisa implica designar toleran­cias estrictas para las dimensiones, lo que se traduce en un alto costo del producto. Actualmente, la filo­sofía de calidad consiste en buscar la excelencia. La investigación que se resume en este artículo tuvo como objetivo establecer los factores que influyen en la mejora de las prácticas de manufactura de partes de acoples o ensambles.

Estos factores resultaron ser el ajuste requerido para el acople final, los equipos y herramientas disponi­bles para el maquinado, el sistema de producción, los equipos y métodos de medición, las condiciones ambientales durante el proceso, el tamaño de las partes, los métodos de manipulación, así como el material utilizado y los procesos o usos posteriores. En la investigación también se estudió el impacto de la filosofía de calidad usada para la manufactura, encontrando que la exactitud de la máquina deter­mina en gran medida la capacidad de cumplimiento de los valores dimensionales especificados.
Evaluación electroquímica de soldaduras en tubos capilares de acero inoxidable
Authors: Rodríguez-Yáñez Javier E. , Saborío-Leiva Ericka , Mora-Montoya Daniel
Published: November 2015

La recuperación de capilares de acero 316L utilizados en pozos geotérmicos neutros, por medio de soldadura orbital autógena, se evalúa desde el punto de vista de su resistencia a la corrosión en las condiciones de utilización, mediante técnicas electroquímicas básicas.

En el pretratamiento se encuentra que es más conveniente realizar un decapado químico previo a la soldadura por 5 minutos. Mientras que posteriormente a la soldadura, la aplicación de tratamiento térmico de reducción de tensiones no se justifica desde el punto de vista de la resistencia a la corrosión.

También se plantea la comparación de los capilares soldados respecto a capilares nuevos y usados, teniendo los capilares soldados un comportamiento intermedio entre ambos.
Principales géneros de nematodos fitoparásitos asociados a plátano y piña en las regiones Huetar Norte y Huetar Atlántica de Costa Rica
Authors: Guzmán-Hernández Tomás De Jesús , Varela-Benavides Ingrid , Hernández-Villalobos Silvia , Durán-Mora Joaquín , Montero-Carmona Wayner
Published: November 2015

Durante esta investigación se muestrearon periódicamente sistemas productivos de piña y plátano en la Región Huetar Norte (RHN) y de piña en la Región Huetar Atlántica (RHA), con el objetivo de identificar los géneros de nematodos fitoparásitos asociados a estos cultivos, su frecuencia y densidad de población. También se exploró la dinámica poblacional de los principales géneros. En el cultivo de piña, los nematodos con mayor densidad de población y más frecuentemente detectados en ambas regiones estudiadas fueron Pratylenchus y Helicotylenchus. Las poblaciones de estos nematodos fueron fluctuantes en la RHN y con un crecimiento que puede explicarse mediante funciones polinómicas en la RHA. En el caso del plátano, los nematodos con mayor densidad de población y más frecuentemente detectados fueron Radopholus similis, Pratylenchus y Meloidogyne. Las poblaciones de estos nematodos también mostraron fluctuaciones en el tiempo.
Producción y exportación de melón (Cucumis melo) en Costa Rica
Authors: Monge-Pérez José Eladio
Published: November 2015

Se estudió la producción y exportación de melón en Costa Rica. Se recopiló y analizó información obtenida a través de diferentes fuentes (FAO, BCCR, PROCOMER, MAG, CANAPEMS). Se estableció comunicación personal con gerentes de empresas exportadoras de melón y se revisaron diversas publicaciones sobre el tema. En este artículo se presentan datos sobre el área de siembra, el número de empresas exportadoras, la distribución geográfica del cultivo, el valor de las exportaciones, las exportaciones por país de destino y por tipo de melón a lo largo de varios años. Finalmente, se analizan los desafíos a nivel agronómico, económico, ambiental y logístico para el futuro de la producción de melón en Costa Rica.
Evaluación de monitores electroquímicos para estudios de corrosión atmosférica del acero carbono
Authors: Garita-Arce Luis
Published: November 2015

El objetivo de la investigación fue evaluar diferentes tipos de monitores electroquímicos para realizar estudios de corrosión atmosférica. Para ello se realizaron corridas en el estado cero de las probetas y condiciones controladas de humedad relativa y temperatura; también se efectuaron corridas a través del tiempo y con probetas activadas hidrofilicamente.  Las técnicas electroquímicas utilizadas son la resistencia de polarización líneal (RPL) y el ruido electroquímico (RE), las cuales tienen como variables respuesta la resistencia de polarización (Rp) y la resistencia al ruido (Rn) respectivamente.  Entre las principales conclusiones tenemos que la probeta de tres electrodos idénticos y la de tipo peineta de tres electrodos presentan mejores resultados con respecto a las variaciones de humedad relativa (HR); sin embargo, se recomienda realizar nuevos electrodos de forma de peineta, con distancias menores de separación entre ellos, para así realizar estudios comparándola con la de tres electrodos idénticos.
Determinación de material y condiciones de trabajo del Torno CNC en la operación de cilindrado
Authors: Hernández-Granados Juan Bautista , Meneses-Guzmán Marcela , Picado-Alvarado Federico
Published: November 2015

Uno de los principales problemas del maquinado es alcanzar la calidad definida del producto bajo las condiciones de trabajo de que se disponga. La operación de cilindrado en el torno CNC del Laboratorio de Sistemas Integrados de Manufactura (SIMTEC) ha sido estudiada con diferentes condiciones de corte (avance, profundidad de corte) y tipo de material (aluminio 6061, acero 1020) para identificar la combinación y el nivel de factores que mejoran el acabado superficial de una pieza. Utilizando tres técnicas de diseño de experimentos (DOE), a saber, diseño factorial, regresión lineal múltiple y de superficie de respuesta (RSM), se identifica que los factores y niveles que reducen la rugosidad superficial son el, y el material aluminio. Se ha establecido un modelo de regresión de primer orden que puede ser utilizado junto con la gráfica RMS para predecir el valor de la rugosidad promedio.
Prueba comparativa de uniformidad de contenido en tabletas de teofilina (150 mg/tab) de dos casas farmacéuticas en Costa Rica
Authors: Pérez-López Esteban , Morales-Alfaro Kevin , Rojas-Hernández Alfonso , Vargas-Vargas Anderson
Published: November 2015

Dada la importancia del medicamento denominado teofilina para su uso en pacientes con problemas de asma y su alto consumo en Costa Rica, se eligió el producto en tabletas de 150 mg de teofilina de una casa farmacéutica que lo produce y distribuye en forma genérica, junto con el que fabrica la Caja Costarricense de Seguro Social (CCSS) en la misma dosis. Se realizó el estudio comparativo de la prueba de uniformidad de contenido para las tabletas de teofilina de 150 mg de la casa farmacéutica LISAN y las fabricadas por la CCSS. La prueba de uniformidad de contenido analíticamente se fundamentó en la absorción y cuantificación del ingrediente activo teofilina a 272 nm para 10 muestras de cada casa farmacéutica, mediante el uso de un espectrofotómetro UV/Vis, empleando como disolvente agua destilada. Se probó un método selectivo, exacto y preciso y se obtuvo como resultado que todas las dosis ensayadas para cada fabricante se encuentran en el rango de 100% a 110%, con respecto a lo etiquetado sobre el principio activo en las tabletas y con un desvío relativo no mayor al 2,5%, cumpliendo holgadamente con lo establecido por la Farmacopea de Estados Unidos para la prueba de uniformidad de contenido.
Validación del constructo, contenido y confiabilidad de indicadores de proceso para la evaluación de la dimensión curricular en la educación superior: el caso del Instituto Tecnológico de Costa Rica
Authors: Lira-Valdivia Rosa Inés
Published: November 2015

En este trabajo se presentan los resultados de la validación efectuada a un conjunto de indicadores con el propósito de utilizarlos en la evaluación de la dimensión Proceso Curricular en una instancia de educación superior, en este caso el Instituto Tecnológico de Costa Rica. Se muestran los resultados relativos a los tres tipos de validez: de constructo, contenido y confiabilidad, incluyendo las correspondientes conclusiones del estudio. El trabajo se enmarca en una investigación evaluativa de enfoque cuantitativo de corte doctoral con la Universidad de Valencia y el Instituto Tecnológico de Costa Rica, utilizando como metodología el juicio de expertos.

Se concluye que los resultados de validez alcanzados ofrecen evidencia suficiente para respaldar los indicadores como ítems de calidad, ampliamente confiables para proporcionar información válida en la evaluación de la dimensión Proceso Curricular. Asimismo, se estima que estos indicadores proveerán información pertinente y serán un insumo importante para la toma de decisiones sobre políticas curriculares y evaluativas en la educación superior.
Evaluación de la corrosión por picadura en aluminio AA1050
Authors: Garita-Arce Luis , Rodríguez-Yáñez Javier E.
Published: November 2015

El aluminio presenta una gran diversidad de usos en la vida actual. La posibilidad de deterioro de este metal debido a la corrosión por picadura es una de las consideraciones principales de los fabricantes, con el fin de evitar reclamos. 

La norma ASTM G100-89 plantea una metodología de valoración del aluminio por medio de la evaluación del potencial frente a la aplicación de polarizaciones galvánicas cíclicas, obteniéndose de ella los potenciales de protección (Eprot) por debajo de los cuales el aluminio puede ser expuesto sin esperar corrosión por picadura. 

En el presente trabajo se plantea la evaluación de la técnica, valorando la corrosión por picadura en aluminios del tipo AA1050, utilizados para la mayoría de las aplicaciones usuales. Las variables consideradas fueron las de exposición habitual para el aluminio en ambientes normales: composición, pH, temperatura y porcentajes de deformación. 

Los ensayos realizados según la norma ASTM G100- 89 para las aleaciones consideradas no indicaron diferencias significativas, aunque sí se observó que la aleación AA1050 presenta mayor susceptibilidad a la picadura en ámbitos de un pH= 7 y con deformaciones elevadas. 
Diseño óptimo de un sistema de distribución de agua (SDA) aplicando el algoritmo Simulated Annealing (SA)
Authors: Méndez-Morales Maikel
Published: November 2015

En este artículo se presenta la aplicación del algoritmo Simulated Annealing (SA) en el diseño óptimo de un sistema de distribución de agua (SDA). El SA es un algoritmo metaheurístico de búsqueda, basado en una analogía entre el proceso de recocido en metales (proceso controlado de enfriamiento de un cuerpo) y la solución de problemas de optimización combinatorios. El algoritmo SA, junto con diversos modelos matemáticos, ha sido utilizado exitosamente en el óptimo diseño de SDA. Como caso de estudio se utilizó el SDA a escala real de la comunidad de Marsella, en San Carlos, Costa Rica. El algoritmo SA fue implementado mediante el conocido modelo EPANET, a través de la extensión WaterNetGen. Se compararon tres diferentes variaciones automatizadas del algoritmo SA con el diseño manual del SDA Marsella llevado a cabo a prueba y error, utilizando únicamente costos unitarios de tuberías. Los resultados muestran que los tres esquemas automatizados del SA arrojaron costos unitarios por debajo del 0.49 como fracción, respecto al costo original del esquema de diseño ejecutado a prueba y error. Esto demuestra que el algoritmo SA es capaz de optimizar problemas combinatorios ligados al diseño de mínimo costo de los sistemas de distribución de agua a escala real. 
Consideraciones de las propiedades mecánicas y térmicas para la elaboración de un ducto de riego a partir de materiales poliméricos postconsumo
Authors: Barrios-Hernández Mary Luz
Published: November 2015

En este artículo se presentan los resultados obtenidos al desarrollar tres nuevas formulaciones a partir de materiales poliméricos generados en el desecho doméstico, con el fin de determinar el mejor material para fabricar poliducto de riego en Costa Rica, utilizando poliducto comercial como referencia. Se recuperó material polimérico postconsumo, específicamente polietilenos y polipropilenos, con la ayuda de actores de programas de recuperación de desechos del Tecnológico de Costa Rica. El material requirió de procesos como limpieza, clasificación, molienda y la extrusión de láminas. Las muestras se prepararon con diferentes proporciones de los polímeros utilizados. Un primer especimen fue de polietileno de baja densidad, otra mezcla fue de 75% de polietileno de baja densidad y 25% de polietileno de alta densidad, y una última mezcla de 75% de polietileno de alta densidad y 25% de polipropileno. A estas muestras se les determinaron propiedades mecánicas y térmicas. 

Como principal resultado se obtuvo que la formulación que mejoró las propiedades estudiadas del poliducto fue la mezcla de diferentes productos de Polietileno de Baja Densidad postconsumo, para un total de 10 repeticiones con 95% de confianza en la prueba de Kolmogorov-Smirnov, concluyendo que este producto supera las propiedades de resistencia en elongación y flexión y que necesita la optimización de las características para resistencia al impacto modo IZOD. Además, la prueba de calorimetría diferencial de barrido demostró la ausencia de agentes externos en la muestras y el análisis termogravimétrico reveló cambios de temperatura de descomposición semejantes al ducto y mayores a las otras mezclas. 
Implementación de la metodología DMAIC-Seis Sigma en el envasado de licores en Fanal
Authors: Pérez-López Esteban , García-Cerdas Minor
Published: November 2015

El presente artículo trata sobre la propuesta de mejora de la eficiencia en la línea de envasado de pet en la Fábrica Nacional de Licores (Fanal), empleando la metodología DMAIC-Seis Sigma. El trabajo se realizó con el fin de solucionar el problema que presentaba la línea de envasado de licores en envase pet, la cual no estaba operando a su máxima capacidad por deficiencias en la línea. Durante el diagnóstico de la situación se pudo determinar que en la línea de envasado de licores en pet se tenían tiempos efectivos de producción muy bajos, exceso de paros en la línea, las máquinas de cada subproceso no alcanzan en ningún momento su capacidad máxima de producción, defectos recurrentes en calidad, procesos repetitivos y desgastantes por parte del personal y no existe capacidad para dar abasto con los picos en temporadas de alta de demanda, entre otros. 

Se proponen algunas soluciones como: medir y monitorear la eficiencia de cada máquina en la línea con un indicador efectivo como el OEE (eficiencia general de los equipos), controlar las paradas no obligatorias de manera que el proceso sea más fluido y expedito, automatizar algunos subprocesos en la línea de manera que los operadores no tengan que realizar trabajos que una máquina puede hacer con facilidad y a menor costo. En síntesis, con la mejora conseguida por medio de la metodología DMAIC-Seis Sigma en la línea de envasado de licores en pet de Fanal se logra pasar de un OEE de 47% al inicio a uno de 80% al final de las mejoras implementadas (entrenamiento al personal de mantenimiento y de la línea, así como la creación del plan de mantenimiento), lo que ofrece una solución integral al problema presentado y permite cubrir la demanda en el período de mayor venta; además de permitir la reducción de tiempos muertos en el proceso y una mayor utilización de los recursos instalados y del recurso humano involucrado, de manera tal que se optimiza a su máximo rendimiento la capacidad de la línea productiva, generándole mayores ingresos anuales a la empresa. 
Baumgarten‘s foundation of modern aesthetics
Authors: Grubor Nebojsa
Published: November 2015

The paper explains Baumgarten?s foundation of modern aesthetics as the
science of sensible cognition. The paper first examines mentalistic paradigm
in modern philosophy as an intellectual background of Baumgarten?s philosophy
and aesthetics (I). This is followed by consideration of Baumgarten?s
definitions of aesthetics from Philosophical meditations of pertaining to
some matters concerning poetry (1735), Metaphysics (1739) and Aesthetics
(1750) (II). Finally, it considers Baumgarten?s definition of aesthetics as
the science of sensible cognition starting from Leibniz?s theory of different
stages of knowledge (III).
Ancient or modern? Alexander G. Baumgarten and the coming of age of aesthetics
Authors: Nannini Alessandro
Published: November 2015

The aim of this essay is to examine Baumgarten?s conception on the history of
aesthetics and on his role in it. In the first part, I analyze the way in
which Baumgarten?s aesthetic innovation has been perceived by two of his
disciples, namely Georg Conrad Winckelmann and Georg Andreas Will. While the
former puts the emphasis on the modernity of aesthetics, Will seems more
inclined to attribute the birth of aesthetics to ancient philosophers.
Despite this apparent disagreement, my thesis is that the basic positions of
the two authors are very similar and find their rationale in Baumgarten?s
peculiar treatment of the issue. Consequently, I set out to inquire into
Baumgarten?s theory, in the attempt to better understand his reconstruction
of the empirical history of aesthetics. My purpose is to see how this
empirical history is framed within a more systematic history which
establishes its guidelines and marks its turning points. Eventually, I take
into account the possible implications of this position with regard to the
question of the origin of aesthetics.
Art: A brief history of absence (From the conception and birth, life and death, to the living deadness of art)
Authors: Dzalto Davor
Published: November 2015

This essay focuses on the logic of the aesthetic argument used in the
eighteenth century as a conceptual tool for formulating the modern concept of
?(fine) art(s).? The essay also examines the main developments in the history
of the art of modernity which were initiated from the way the ?nature? of art
was conceived in early modern aesthetics. The author claims that the
formulation of the ?aesthetic nature? of art led to the process of the
gradual disappearance of all of the formal elements that had previously
characterized the visual arts; the result was ?emptiness? or ?nothingness? as
art. The author refers to this process in terms of ?vanishing acts? that
allow for the formulation of an aesthetics of absence in connection to
twentieth-century art (complementing the ?sthetik der Absenz, formulated in
German art theory). The author also briefly addresses the consequences that
these processes have for the way contemporary art, and art world operate.
"Taking the human out of human rights" human rights or group rights?
Authors: Bojanic Petar
Published: November 2015

What interest me are the reasons why ?human? or ?human rights? could be
important or possibly most important in constituting a group (hence the
introduction of the complicated word ?group? and ?group right(s)? in the
subtitle). If I had to justify the existence of the latest debates on nature,
justification and universality of human rights, on their distinction from
other normative standards, on the philosophy and (legal) foundation of human
rights, on ?Human Rights without (or with) Foundations? (Raz, Tasioulas,
Besson), then I would immediately conclude that this ?process of grandiose
concretization? of a complete fabrication is far from over. Despite the
innumerable pacts and international conventions established after World War
II, the slew of obligations to which states have agreed in the last few
decades, the establishment of rights to secession or humanitarian
intervention it is as if the constitution of classification of basic human
rights and their universality is far from over.
The reasons for the moral partiality
Authors: Sládecek Michal
Published: November 2015

In the first part of this text, the author explains the arguments against
partiality in moral decision-making, as well as the arguments advocating for
partiality and indicating to limitations and possible unacceptable
consequences of impartial position. The central part of the text concerns the
moral status of personal projects and the issue of whet her and how relation
ships and close ness between persons are relevant for moral decision-making.
The final part discusses the importance of reflection regarding the limits of
validity of moral reasons of partiality, while pointing at the crucial
importance of nature of relations between people, the context and moral
relevance or the significance of case to which moral assessment refers.
The presence of non-carious lesions in children
Authors: Demko-Rihter Ivana , Jovanov Gordana , Petrovic Bojan , Blagojevic Duska , Petrovic Djordje , Markovic Dejan , Dmitrovic Jelena
Published: November 2015

Introduction. A non-carious lesion (NCL) is the loss of hard dental tissue on
the neck, tuberculum and incisal edges of the teeth. Interest in clinical
presence and in unclear etiology of these lesions allows for their future
prevention and treatment. Objective. The aim of the study was to determine
presence and clinical characteristics of NCLs and dentine hypersensitivity
(DH), as well as their possible risk factors in children, in the population
of the city of Novi Sad. Methods. A total of 55 subjects were included in the
present study, aged between three and 18 years. Each subject completed a
structured questionnaire related to the etiological factors, and all teeth of
each subject were examined by two independent clinical dentists to determine
NCLs and DH. In the case of small children, their parents or guardians filled
out the questionnaire. Teeth with NCLs and DH were diagnosed according to the
Basic Erosive Wear Examination (BEWE) index and by a blast of air according
to Schiff and Hypersensitivity Index. The review was carried out by
inspection and probing. Results. The data were analyzed by clinical
examination and comparison of the answers to the questionnaires. We observed
an increased presence of non-caries lesions on primary teeth, compared to
permanent teeth, with a statistically significant difference (?2=3.86, df=1,
p=0.04). The changes were observed in 82 teeth, and were most frequent on the
canine deciduous teeth (65%) and canine permanent teeth (51%). BEWE index was
10-11% to 92-100% in permanent, and 51-57% in deciduous teeth. Majority of
patients with primary teeth (89.36%) did not respond to air stimulus, while
most patients with permanent teeth (74.29%) did not react to Schiff Index. In
the estimate of sensitivity, the respondents reported hypersensitivity on
6.38% of the deciduous teeth and 22.86% of the permanent teeth. Comparison of
etiology factors did not reveal a direct link with the appearance of NCLs.
Conclusion. Research has shown that despite the lack of subjective symptoms,
these lesions have distinct clinical characteristics. The fact that they
occur even in deciduous dentition justifies the need for further
investigations.
Neonatal abstinence syndrome: Diagnostic dilemmas in the maternity ward
Authors: Lazic-Mitrovic Tanja , Mikovic Zeljko , Mandic Vesna , Hajnal-Avramovic Lidija , Cecez Djurdjica , Stanimirovic Aleksandar , Jankovic Borisav
Published: November 2015

Introduction. Neonatal abstinence syndrome (NAS) refers to a newborn
neurological, gastrointestinal and/or respiratory disorder if a newborn was
exposed to psychoactive substances in the intrauterine period. NAS is
difficult to diagnose due to unreliability of the data on addictive
substances use during pregnancy, limited possibilities of the prenatal
exposure diagnosis and postnatal substance detection, which all lead to
diagnostic dilemmas. Objective. The aim of this study was to indicate the
problems in patients with early NAS diagnosis in the maternity ward and the
importance of clinical presentation used as a guide toward the diagnosis.
Methods. This retrospective study included five term eutrophic newborns with
high Apgar score, good adaptation in the first day and with clinical
presentation of NAS during the second day of life. The clinical presentation
was dominated by irritability, increased wakefulness, increased muscle tone,
shrilly crying, tremors, problems with accepting food, tachypnea,
subfebrility and hyperhidrosis. Finnegan scale was introduced in order to
diagnose NAS and apply the therapy. Single-medication therapy of
phenobarbitone was applied in four cases and a combination of phenobarbitone
and morphine in one case. For toxicological analysis newborns? urine samples
were used. Results. Conditions such as perinatal asphyxia, infection, hunger,
polycythemia, hypoglycemia or hypocalcemia were excluded. Finnegan score
implied that pharmacological treatment had to be administered. The
discrepancy between the NAS anamnesis and toxicological analysis existed.
Response to the treatment was positive in all cases. Conclusion. NAS is a
multisystemic disorder and should be suspected when it is noticed that
children exhibit characteristic signs. However, other pathological conditions
have to be excluded. Quantification according to the adopted scales for NAS
leads toward appropriate treatment and recovery of the newborns.
Levels of vascular endothelial growth factor during first six months of peritoneal dialysis
Authors: Stojimirovic Biljana , Jovanovic Natasa , Trbojevic-Stankovic Jasna , Krstic Slobodan , Nesic Dejan , Zunic-Bozinovski Snezana
Published: November 2015

Introduction. Chronic peritoneal dialysis (PD) up-regulates vascular
endothelial growth factor (VEGF) synthesis and VEGF is found in drained
dialysate (dd). Objective. Aims of this prospective study were to evaluate
serum (s) and ddVEGF concentration during the first six months of PD,
relationships between these concentrations and demographic and biochemical
parameters, presence of diabetes, peritonitis, and the use of medications.
Methods. The study included 20 patients, with the mean age of 62.9?12.69, 11
of whom were affected by diabetes mellitus. Fasting venous blood samples were
taken at the beginning and after six months of PD, in tri-potassium
ethylenediaminetetraacetic acid (K3EDTA) vacutainer. Results. After six
months of PD, sVEGF concentrations increased significantly, without
significant change in ddVEGF. Concentrations of sVEGF at the beginning of
chronic PD treatment directly significantly correlated with serum fibrinogen,
and after six months with fibrinogen and glycemia. In patients receiving
erythropoiesis-stimulating agent (ESA), levels of sVEGF and ddVEGF were lower
at baseline, while after six months of PD ddVEGF increased. In patients not
receiving ESA, sVEGF increased more prominently, while ddVEGF decreased. The
changes were not statistically significant. Patients receiving
angiotensinconverting- enzyme inhibitor (ACEi) had sVEGF and ddVEGF levels
insignificantly lower than those not using ACEi, however sVEGF significantly
increased during six months of PD. After six months of PD, ddVEGF was
significantly higher compared to those not using ACEi. Treatment with statins
did not significantly influence levels of sVEGF and ddVEGF during the
follow-up. Concentrations of sVEGF were continually lower than those of
ddVEGF and increased more, while concentrations of ddVEGF were higher in
patients using statins. Conclusion. Serum and drained dialysate
concentrations of VEGF in PD patients were connected with poorer metabolic
profile, while the role of inflammation and treatment agents should be
studied further.
Fixed combinations of glaucoma medications
Authors: Babic Nikola
Published: November 2015

The first line treatment in the management of glaucoma is topical medical
therapy. Many patients with glaucoma require multiple medications for
adequate intraocular pressure control. For patients who need multi-dose
regimens to control intraocular pressure, fixed combinations offer
convenience, efficacy and safety. This review summarizes the role, efficacy,
mechanism of action and indications for use of modern fixed combination of
topical glaucoma medications. The review shows the advantages and
disadvantages of a prescribing fixed combination in daily clinical practice.
Resource based view and resource dependence theory in decision making process of public organisation - research fi ndings
Authors: Frączkiewicz-Wronka Aldona , Szymaniec Karolina
Published: November 2015

Resource based view and resource dependence theory in decision making process of public organisation - research findings One of the premises which build relationships between stakeholder and a public organisation are stakeholder’s resources which public organisation would like to possess and use. The other one is configuration of resources possessed by the public organisation that should allow the unit in question to realize stakeholder’s expectations. Above observations lead scientific inquiries to the two management theories - resource-based view (RBV) and resource dependence theory (RDT). The first one is orientated at resources owned by the organisation, the second one is orientated at the resources obtained from environment. The objective of this article is identification which orientation, RBV or RDT, dominates in decision making process in public organisations.
Predicting shunt failure in children: should the global shunt revision rate be a quality measure?
Authors: Rossi Nicholas B. , Khan Nickalus R. , Jones Tamekia L. , Lepard Jacob , McAbee Joseph H. , Klimo Paul
Published: November 2015

OBJECT

Ventricular shunts for pediatric hydrocephalus continue to be plagued with high failure rates. Reported risk factors for shunt failure are inconsistent and controversial. The raw or global shunt revision rate has been the foundation of several proposed quality metrics. The authors undertook this study to determine risk factors for shunt revision within their own patient population.

METHODS

In this single-center retrospective cohort study, a database was created of all ventricular shunt operations performed at the authors’ institution from January 1, 2010, through December 2013. For each index shunt surgery, demographic, clinical, and procedural variables were assembled. An “index surgery” was defined as implantation of a new shunt or the revision or augmentation of an existing shunt system. Bivariate analyses were first performed to evaluate individual effects of each independent variable on shunt failure at 90 days and at 180 days. A final multivariate model was chosen for each outcome by using a backward model selection approach.

RESULTS

There were 466 patients in the study accounting for 739 unique (“index”) operations, for an average of 1.59 procedures per patient. The median age for the cohort at the time of the first shunt surgery was 5 years (range 0–35.7 years), with 53.9% males. The 90- and 180-day shunt failure rates were 24.1% and 29.9%, respectively. The authors found no variable—demographic, clinical, or procedural—that predicted shunt failure within 90 or 180 days.

CONCLUSIONS

In this study, none of the risk factors that were examined were statistically significant in determining shunt failure within 90 or 180 days. Given the negative findings and the fact that all other risk factors for shunt failure that have been proposed in the literature thus far are beyond the control of the surgeon (i.e., nonmodifiable), the use of an institution’s or individual’s global shunt revision rate remains questionable and needs further evaluation before being accepted as a quality metric.
Reevaluating the weekend effect on patients with hydrocephalus undergoing operative shunt intervention
Authors: Attenello Frank J. , Christian Eisha , Wen Timothy , Cen Steven , Zada Gabriel , Kiehna Erin N. , Krieger Mark D. , McComb J. Gordon , Mack William J.
Published: November 2015

OBJECT

Recently published data have suggested an increase in adverse outcomes in pediatric patients after insertion or revision of a ventricular CSF diversion shunt after a same-day weekend procedure. The authors undertook an evaluation of the impact of weekend admission and time to shunting on surgery-related quality outcomes in pediatric patients who underwent ventricular shunt insertion or revision.

METHODS

Pediatric patients with hydrocephalus who underwent ventriculoperitoneal, ventriculoatrial, or ventriculopleural shunt placement were selected from the 2000–2010 Nationwide Inpatient Sample and Kids’ Inpatient Database. Multivariate regression analyses (adjusted for patient, hospital, case severity, and time to shunting) were used to determine the differences in inpatient mortality and routine discharge rates among patients admitted on a weekday versus those among patients admitted on a weekend.

RESULTS

There were 99,472 pediatric patients with shunted hydrocephalus, 16% of whom were admitted on a weekend. After adjustment for disease severity, time to procedure, and admission acuity, weekend admission was not associated with an increase in the inpatient mortality rate (p = 0.46) or a change in the percentage of routine discharges (p = 0.98) after ventricular shunt procedures. In addition, associations were unchanged after an evaluation of patients who underwent shunt revision surgery. High-volume centers were incidentally noted in multivariate analysis to have increased rates of routine discharge (OR 1.04 [95% CI 1.01–1.07]; p = 0.02).

CONCLUSIONS

Contrary to those of previous studies, the authors’ data suggest that weekend admission is not associated with poorer outcomes for ventricular shunt insertion or revision. Increased rates of routine discharge were noted at high-volume centers.
Trends in hospitalization of preterm infants with intraventricular hemorrhage and hydrocephalus in the United States, 2000–2010
Authors: Christian Eisha A. , Jin Diana L. , Attenello Frank , Wen Timothy , Cen Steven , Mack William J. , Krieger Mark D. , McComb J. Gordon
Published: November 2015

OBJECT

Even with improved prenatal and neonatal care, intraventricular hemorrhage (IVH) occurs in approximately 25%–30% of preterm infants, with a subset of these patients developing hydrocephalus. This study was undertaken to describe current trends in hospitalization of preterm infants with posthemorrhagic hydrocephalus (PHH) using the Nationwide Inpatient Sample (NIS) and the Kids’ Inpatient Database (KID).

METHODS

The KID and NIS were combined to generate data for the years 2000–2010. All neonatal discharges with ICD-9-CM codes for preterm birth with IVH alone or with IVH and hydrocephalus were included.

RESULTS

There were 147,823 preterm neonates with IVH, and 9% of this group developed hydrocephalus during the same admission. Of patients with Grade 3 and 4 IVH, 25% and 28%, respectively, developed hydrocephalus in comparison with 1% and 4% of patients with Grade 1 and 2 IVH, respectively. Thirty-eight percent of patients with PHH had permanent ventricular shunts inserted. Mortality rates were 4%, 10%, 18%, and 40%, respectively, for Grade 1, 2, 3, and 4 IVH during initial hospitalization. Length of stay has been trending upward for both groups of IVH (49 days in 2000, 56 days in 2010) and PHH (59 days in 2000, 70 days in 2010). The average hospital cost per patient (adjusted for inflation) has also increased, from $201,578 to $353,554 (for IVH) and $260,077 to $495,697 (for PHH) over 11 years.

CONCLUSIONS

The number of neonates admitted with IVH has increased despite a decrease in the number of preterm births. Rates of hydrocephalus and mortality correlated closely with IVH grade. The incidence of hydrocephalus in preterm infants with IVH remained stable between 8% and 10%. Over an 11-year period, there was a progressive increase in hospital cost and length of stay for preterm neonates with IVH and PHH that may be explained by a concurrent increase in the proportion of patients with congenital cardiac anomalies.
Predicting discharge destination with admission outcome scores in stroke patients
Authors: Ouellette D.S. , Timple C. , Kaplan S.E. , Rosenberg S.S. , Rosario E.R.
Published: November 2015

BACKGROUND:

The goal of this study was to predict the discharge location for stroke patients.

OBJECTIVE:

To design a tool to assess a community discharge that will assist in development of individualized care plans and discharge planning.

METHODS:

Patients ( N = 407) hospitalized for an acute stroke in an inpatient rehabilitation facility were used for this retrospective study. Admission data from the Functional Independence Measure (FIM) and Simplified Stroke Rehabilitation Assessment of Movement (S-STREAM) were used to determine predictive factors for a community discharge.

RESULTS:

Logistic regressions and chi-square analyses were used to determine admission factors that predict a community discharge and the cut off score for each predictive variable. The S-STREAM, Motor FIM, Total FIM, FIM Bladder, FIM bed transfer, FIM toilet transfer, FIM bathing, and FIM memory were predictive of a community discharge. A predictive tool with a sensitivity and specificity of 76% and 64% was developed using the combined relative risk scores of the S-Stream, FIM Bladder, FIM Bed Transfer and FIM Memory.

CONCLUSIONS:

By using outcome data at the time of admission, a discharge destination can be predicted for stroke patients with significant sensitivity and specificity.
Fatty replacement of rotator cuff in brain-injured patients is associated with hemiplegic arm function, but not with tendon tear: A multicenter study
Authors: Beom Jaewon , Jang Hye Jin , Han Tai Ryoon , Oh Byung-Mo , Paik Nam-Jong , Yang Eun Joo , Lee Shi-Uk
Published: November 2015

BACKGROUND:

The association between fatty replacement of rotator cuff and hemiplegic upper extremity function has not been defined yet. Moreover, the relationships among rotator cuff tears, shoulder pain, spasticity, and fatty replacement were not clearly studied.

OBJECTIVE:

We investigated the association of fatty replacement of the supraspinatus and infraspinatus muscles with tendon tear in stroke or brain-injured patients.

METHODS:

A total of 72 hemiplegic patients were enrolled in 3 hospitals, and ultrasonography of both shoulders was performed once. Fatty replacement of the supraspinatus and infraspinatus was graded by the visibility of outer contours, pennate pattern, central tendon, and echogenicity.

RESULTS:

Fatty replacement was observed in 22 (30.6%) out of the 72 patients (in 18 supraspinatus muscles and 12 infraspinatus). Inter-rater agreement (kappa value) between the 2 physiatrists was 0.530 for the supraspinatus, and 0.411 for the infraspinatus. The Fugl-Meyer assessment score, Brunnstrom stage, and modified Barthel index were significantly lower in patients with fatty replacement of the supraspinatus or infraspinatus (group 1) than in those without (group 2). The motor power of both shoulders, the pain-free range of motion, spasticity, and hemiplegic shoulder pain were comparable between the two groups. The tear rate of the supraspinatus, infraspinatus, or subscapularis tendon at the hemiplegic side was higher than that at the contralesional side in each group, although there was no significant difference between group 1 and group 2.

CONCLUSION:

Disuse leading to muscle atrophy rather than rotator cuff tear might be the cause of fatty replacement of these muscles, which may be associated with decreased function of the hemiplegic upper extremities.
Swallowing function after occipitocervical arthrodesis for cervical deformity in patients with rheumatoid arthritis
Authors: Ebata Shigeto , Hatsushika Kyousuke , Ohba Tetsuro , Nitta Kyohko , Akaike Hiroshi , Masuyama Keisuke , Haro Hirotaka
Published: November 2015

BACKGROUND:

Some patients develop dysphagia after OC arthrodesis with RA. A previous report has indicated that establishing appropriate occipito-C2 is important for avoiding these side effects. However, a more recent report has demonstrated that the O-C2 angle did not have a significant effect on the incidence of postoperative dysphagia.

OBJECTIVE:

To investigate the swallowing function of patients with rheumatoid arthritis (RA) before and after they underwent occipitocervical (OC) fusion.

METHODS:

The study was performed in collaboration with the Departments of Orthopaedic, Otorhinolaryngology, and Rehabilitation. Seven consecutive patients (3 men and 4 women; mean age, 66.4 years) with RA-induced upper cervical deformity were enrolled from 2013 to 2014. The patients underwent deglutition analysis, which was performed by otorhinolaryngologists, before and after surgery, and comprised videofluoroscopy and fiberoptic endoscopy. We examined the relationship between imaging studies and swallowing function.

RESULTS:

Preoperatively, subjective dysphagia was reported by 2 patients. Videofluoroscopy identified dysmotility of the epiglottis and incomplete closure of the laryngeal inlet in 2 patients, with contrast medium entering the larynx, and endoscopy identified food residue in the larynx of 1 patient during swallowing evaluation. Postoperatively, 2 patients with preoperative impaired deglutition showed dysphagia. Imaging examinations of the 2 patients revealed a 10°-reduction in the O-C2 angle of 1 patient, but the angle was unchanged in the other patient.

CONCLUSIONS:

To the best of our knowledge, this is the first report to evaluate swallowing function before and after O-C3 arthrodesis. The preoperative O-C2 angle was unchanged after surgery. Impairment of deglutition may be closely associated with air leakage from the oropharynx due to impaired mobility of the soft palate. Because the precise mechanism of dysphagia has not been fully elucidated, further study using dynamic videofluoroscopy and videoendoscopy is needed to examine the swallowing mechanism.
An Assessment of Air Pollution Exposure Information for Health Studies
Authors: Lipfert Frederick
Published: November 2015

Most studies of air pollution health effects are based on outdoor ambient exposures, mainly because of the availability of population-based data and the need to support emission control programs. However, there is also a large body of literature on indoor air quality that is more relevant to personal exposures. This assessment attempts to merge these two aspects of pollution-related health effects, emphasizing fine particles. However, the basic concepts are applicable to any pollutant. The objectives are to examine sensitivities of epidemiological studies to the inclusion of personal exposure information and to assess the resulting data requirements. Indoor air pollution results from penetration of polluted outdoor air and from various indoor sources, among which environmental tobacco smoke (ETS) is probably the most toxic and pervasive. Adequate data exist on infiltration of outdoor air but less so for indoor sources and effects, all of which have been based on surveys of small samples of individual buildings. Since epidemiology is based on populations, these data must be aggregated using probabilistic methods. Estimates of spatial variation and precision of ambient air quality are also needed. Hypothetical personal exposures in this paper are based on ranges in outdoor air quality, variable infiltration rates, and ranges of indoor source strength. These uncertainties are examined with respect to two types of mortality studies: time series analysis of daily deaths in a given location, and cross-sectional analysis of annual mortality rates among locations. Regressions of simulated mortality on personal exposures, as affected by all of these uncertainties, are used to examine effects on dose-response functions using quasi-Monte Carlo methods. The working hypothesis is that indoor sources are reasonably steady over time and thus applicable only to long-term cross-sectional studies. Uncertainties in exposure attenuate the simulated mortality regression coefficients; correlations between “true” and hypothesized exposures are used to compare their effects. For a given exposure uncertainty level, attenuation of regression coefficients is similar for both types of simulated mortality studies, but since cross-sectional studies involve indoor sources they are more sensitive, to the point where regression coefficients may be driven to zero. The most pressing need for confirming data is the distribution of indoor sources among cities, especially for ETS.
Active Packaging Coatings
Authors: Bastarrachea Luis , Wong Dana , Roman Maxine , Lin Zhuangsheng , Goddard Julie
Published: November 2015

Active food packaging involves the packaging of foods with materials that provide an enhanced functionality, such as antimicrobial, antioxidant or biocatalytic functions. This can be achieved through the incorporation of active compounds into the matrix of the commonly used packaging materials, or by the application of coatings with the corresponding functionality through surface modification. The latter option offers the advantage of preserving the packaging materials’ bulk properties nearly intact. Herein, different coating technologies like embedding for controlled release, immobilization, layer-by-layer deposition, and photografting are explained and their potential application for active food packaging is explored and discussed.
Coating Acetylated Wood
Authors: Rowell Roger , Bongers Ferry
Published: November 2015

Wood exposed to the outdoor environment is susceptible to weathering due to a series of chemical, biological and physical processes. Acetylation of wood is known to reduce cell wall moisture content, improve dimensional stability and durability against fungal decay. As a result of these improvements, less stress is created between the coating and the wood surface improving the performance of the coating and increasing its useful lifetime. This paper is a review of research done on the chemistry of the acetylation process, the coating performance of acetylated wood and concentrates on the factors influencing coating performance.
Quantitative Evaluation of Photoinduced Bending Speed of Diarylethene Crystals
Authors: Kitagawa Daichi , Iwaihara Chika , Nishi Hiroyasu , Kobatake Seiya
Published: November 2015

We investigated photoinduced crystal bending behavior of various photochromic diarylethenes. In all the diarylethene derivatives we used in this work, the relationship between the initial photoinduced bending speed and the crystal thickness was well explained by the easy-handled Timoshenkoʼs bimetal model. Moreover, we proposed a quantitative analysis method to reveal the relationship between the bending speed and the molecular structure of diarylethenes. These results provide the quantitative evaluation method of the photoinduced crystal bending speed.