bluuebunny/crossref_metadata_2025 huggingface dataset:
Desarrollo e implementación de una interfaz gráfica de usuario para el cálculo y comparación de modelos de propagación electromagnética en exteriores
Authors: Eslava Gutiérrez M. A. , Vidal Beltrán S. , López Bonilla José Luis
Published: July 2016

Este trabajo, muestra el desarrollo e implementación de una herramienta de software para predecir la propagación electromagnética de señales en sistemas de comunicaciones móviles de tercera generación usando tres modelos de propagación (Okumura-Hata, Cost Walfish-Ikegami y 3GPP), los cuales son empleados en la planeación de cobertura de Sistemas  3G y posteriormente comparar el resultado con mediciones obtenidas en campo en distintos escenarios urbanos. Esta comparación de los modelos se realizó haciendo un análisis del error correspondiente con cada zona de estudio. Finalmente, los resultados obtenidos a través de la herramienta para cada modelo se muestran en mapas de estimación de cobertura usando un Sistemas de Información Geográfica (GIS, Geographic Information System).
Preferencias de las personas a las prestaciones y beneficios otorgados en su trabajo
Authors: Madero-Gómez Sergio M. , Calderón Leyva Victor , Velez Francisco
Published: July 2016

Las empresas que cuentan con procesos formales de compensaciones tienen la necesidad de estar revisándolos continuamente tratando de convertirlos en una ventaja competitiva que sea fundamental en el desarrollo del personal y de la empresa. Debido a la situación económica que se tiene en la que no es fácil ofrecer aumentos de salarios de doble dígito, es necesario analizar el paquete de prestaciones y beneficios que se ofrece en la empresa para identificar si están vigentes y además son importantes para el trabajador. Al llevar a cabo la aplicación de 123 cuestionarios dentro de una empresa del sector manufacturero del noroeste de México, encontramos que el fondo de ahorro, los vales de despensa, el aguinaldo, las instalaciones de trabajo debidamente refrigeradas y las condiciones de seguridad fueron los 5 beneficios/prestaciones más importantes de una lista de 30 que se utilizaron en el estudio.
La orientación al mercado en las mipymes de San Luis Potosí
Authors: Rodríguez Gutiérrez Paola Isabel , Ramos Ávila Adriana Eugenia , Pastor Pérez María Del Pilar
Published: July 2016

Introducción: El objetivo principal de la cultura organizacional orientada al mercado es proveer un valor superior a los clientes, sin dejar de lado la relevancia de la relación de la empresa con competidores y accionistas internos. En este sentido, el propósito del presente estudio es llevar a cabo un análisis descriptivo de los componentes que integran el constructo de la orientación al mercado, así como probar si existe una relación entre esta variable y el desempeño empresarial.Método: Con el fin de lograr el objetivo planteado se hizo un diseño cuantitativo. La población objeto de la investigación es la totalidad de mipymes de la ciudad de San Luis Potosí, registradas en el Directorio Estadístico Nacional de Unidades Económicas de INEGI. El muestreo fue aleatorio simple y la muestra consistió en 331 empresas (intervalo de confianza del 93% y precisión del 5%). La encuesta se aplicó cara a cara y se tuvo un 33.8% de tasa de respuesta.Resultados: Los resultados muestran un alto grado de consistencia interna en cada una de las variables analizadas. La prueba de hipótesis realizada muestra que hay una relación positiva entre la orientación al mercado y el desempeño.Conclusión: A partir de este estudio se sugiere que una gran proporción de las micro, pequeñas y medianas empresas potosinas, ponen en primer lugar la atención a las necesidades de los clientes, toman en cuenta las fortalezas propias de las organización para crear un valor superior y se encuentran atentos a las propuestas de la competencia, lo cual se relaciona a su desempeño.
Transitorios electromecánicos en sistemas de potencia industriales
Authors: Sánchez-García Héctor Manuel , Calderón-Guizar Jorge Guillermo
Published: July 2016

Los estudios de estabilidad transitoria o transitorios electromecánicos son frecuentemente ignorados en el ámbito de los sistemas eléctricos de potencia industriales, a pesar de que la información obtenida a partir de dichos estudios resulta fundamental para entender el comportamiento dinámico de sistemas eléctricos de potencia de cualquier tipo, así como para identificar la necesidad de acciones correctivas y evaluar su efectividad sobre la seguridad operativa del sistema eléctrico. En este artículo se analiza el comportamiento dinámico de un sistema de potencia industrial con generación propia, interconectado a la red pública del sistema de transmisión, al ocurrir una falla en el transformador de interconexión entre ambos sistemas. El análisis reportado en el presente trabajo resultó ser una parte fundamental para entender el porqué de la actuación de las protecciones de baja y alta frecuencia de los generadores y en consecuencia el colapso total del sistema industrial.
Descripción de los sistemas intensivos de engorda de corderos en Yucatán, México
Authors: Muñoz-Osorio Germani Adrian , Aguilar-Caballero Armando Jacinto , Sarmiento-Franco Luis Armando , Wurzinger Maria , Cámara-Sarmiento Ramón
Published: July 2016

El objetivo del estudio fue describir los sistemas intensivos de engorda de corderos en el Estado de Yucatán, México. El estudio se desarrolló de marzo a junio de 2013. Se aplicó una encuesta a productores o responsables de 34 granjas, seleccionadas por conveniencia. La información fue analizada a través de tablas de frecuencias, medidas de tendencia central y análisis de varianza obtenidos con el paquete estadístico STATGRAPHICS® Centurion XV. Los resultados mostraron que los sistemas intensivos de engorda de corderos se diferencian básicamente por dos tipos de alojamiento: a) corrales a nivel del suelo (SICS) y b) corrales elevados con piso de rejilla (SICE). Los genotipos están formados por la cruza de razas Pelibuey, Dorper y Katahdin, principalmente (93.94 %). La alimentación se basa en la utilización de concentrados de marcas comerciales (47.06 %), elaborados en la granja (47.06 %) y elaborados por proveedores informales (5.88 %). El manejo sanitario consiste en la vacunación (79.41 %) y desparasitación de los animales (100 %). Se encontró, un mejor comportamiento productivo de los corderos de engorda en SICE comparado con aquellos de SICS. La venta de corderos en pie (91.18 %) es la principal fuente de ingresos económicos, con un precio de $29.75/kg. La mayoría de los productores (67.65 %) comercializan a sus animales en la unidad de producción. Es necesario hacer una evaluación prospectiva de los SICE y los SICS desde el punto de vista productivo y económico.
Demanda de agua de uso comercial en La Reserva de La Biosfera El Vizcaíno, México: Una estimación con datos de panel
Authors: Almendarez Hernández Marco Antonio , Avilés Polanco Gerzaín , Beltrán Morales Luis Felipe
Published: July 2016

La mayor parte de la literatura sobre demanda de agua urbana se ha enfocado en estimar los determinantes de la demanda de agua de uso residencial y existe poca evidencia empírica sobre la demanda de agua de uso comercial (Worthington, 2010). El análisis se ha centrado en áreas urbanas y no se ha abordado dentro de áreas naturales protegidas, particularmente en regiones áridas. El recurso hídrico es un insumo fundamental para el desarrollo de las actividades productivas, la generación de valor agregado y la cantidad de abastecimiento que necesita el personal que labora en el sector comercial. Además, los organismos encargados de la prestación de los servicios de agua potable y alcantarillado enfrentan serios problemas económicos como el pago no oportuno por parte de los usuarios beneficiados, así como insuficiencia de medidores para cuantificar con precisión la provisión del líquido, provocando una menor facturación y una restricción en el control de la demanda. Situación que merece un mayor tratamiento aplicado. El presente trabajo tiene como objetivo analizar la respuesta de los consumidores de agua comercial ante los cambios en su precio en el corto y largo plazo. Asimismo, mide el efecto de la falta del cobro, la proporción de usuarios que cuentan con medidor y otras variables como la temperatura promedio y la precipitación sobre el nivel de consumo. Se estimó una función dinámica de demanda de agua con especificación del precio promedio utilizando una estructura de panel de datos. Los resultados señalan que el precio impacta negativamente en el consumo con una magnitud baja. La elasticidad precio de corto y largo plazo fueron menores que uno, con -0.07 y -0.18, respectivamente. La elasticidad de la temperatura fue de 0.09, la semielasticidad del incumplimiento de pago fue de 0.20 y la proporción de tomas que cuentan con medidor fue de 0.23.
Dos geometrías aplicadas a estructuras de defectos sobre planos de tierra rectangulares y circulares
Authors: Tecpoyotl-Torres Margarita , Vera-Dimas José Gerardo , Flores-Gonzalez Miguel Angel , Vargas-Bernal Rafael
Published: July 2016

En este trabajo se compara el rendimiento de una antena de parche rectangular realizada sobre planos de tierra rectangular y circular, respectivamente. Se observa una mayor ganancia para el caso circular pero un menor ancho de banda. La comparación se llevó a cabo también cuando a los planos de tierra se agregaron defectos. Como resultado, se observaron cambios en las ganancias, el parámetro S11 y los anchos de banda.Para la antena rectangular sobre substrato rectangular con Defectos en el Substrato (DGS, por sus siglas en inglés) la principal mejora observada fue sobre el parámetro S11. Para el caso del plano de tierra (o substrato) circular, el ancho de banda muestra un incremento de 113.59% comparado con el caso sin defectos. Las antenas fueron simuladas utilizando el software FEKO.
Calificación ambiental de la vivienda. Estrategias de adaptabilidad higrotérmica
Authors: Fuentes Pérez Carlos Alberto
Published: July 2016

La calificación ambiental térmica es el procedimiento mediante el cual se evalúan las consecuencias de la implantación, ampliación, modificación o traslado de las actividades y elementos al interior de la vivienda estudio de caso, para comprobar y determinar las medidas correctoras o precautorias necesarias para prevenir o compensar sus posibles efectos térmicos sobre los espacios. Donde se argumentará que la climatología urbana y el sistema constructivo establecen el ambiente higrotérmico. Se observa y monitorea los valores térmicos y su oscilación, de consigna fijada para invierno y verano. Con base en los resultados se determina el comportamiento anual de temperatura y humedad relativa medio mensual así como las estrategias de adaptabilidad y la clasificación higrotérmica. El trabajo metodológicamente es una investigación experimental aplicada, donde los diferentes métodos se apoyan en varios tipos como el documental, de campo y descriptivo. El objetivo de la presente investigación es determinar la calificación ambiental térmica únicamente de temperatura y humedad relativa, al interior de la vivienda común en Tampico, México.
Piroxicam y cambios ováricos de cabras adultas
Authors: Miranda Jiménez Leonor
Published: July 2016

La función de los ovarios puede alterarse por inhibidores de la enzima ciclooxigenasa (COX). La aplicación de piroxicam, antiinflamatorio no esteroideo e inhibidor de COX es de amplio uso veterinario (AINE) y puede alterar la función de los ovarios. El objetivo de esta investigación fue evaluar los cambios extra e intraováricos en cabras adultas en respuesta a piroxicam. En seis cabras adultas de entre 35 y 40 kg de peso vivo, se sincronizaron estros y ovulación, mediante la colocación de CIDR (dispositivo intravaginal de liberación controlada de P4) durante 11 días, al retirar el CIDR se aplicaron prostaglandinas F2α y 400 UI de eCG (inducción de la ovulación). Antes (24 h),  de la inducción de ovulación al grupo testigo y tratado (n=3) se les hicieron  cuatro aplicaciones intramusculares de un ml de solución salina o piroxicam (1.5 mg-1 kg de peso vivo) con intervalo de 24 h. Posterior a la primera aplicación de piroxicam (144 h) se extrajeron los ovarios. Se colectaron muestras sanguíneas cada 24 h; desde 48 h antes de la inducción de la ovulación y, hasta la ovariectomía. En ovario derecho e izquierdo se cuantificó el número y tamaño de folículos y cuerpos lúteos superficiales. En 16 cortes histológicos de cada ovario, se evaluaron las mismas estructuras con localización intraovárica. En suero sanguíneo se determinó la concentración sérica de progesterona (P4) y estradiol (E2). En los datos de folículos y CL se realizó la prueba de suma de rangos de Wilcoxon. Mientras que, P4 y E2 se analizaron utilizando modelos para datos con medidas repetidas (modelos mixtos lineales), los cuales fueron ajustados usando el programa estadísto R. La significancia en los resultados se consideró con α< 0.05. La aplicación de piroxicam disminuyó el número de folículos intraováricos (P< 0.0001) y el de CL intraováricos en desarrollo (P=0.04). Los niveles de P4 y E2 no se modificaron por aplicación de piroxicam (P=0.2), aunque, P4 mostró elevación en concentración, coincidente con el momento de inducción de la ovulación, pero no con el tratamiento (0h; P=0.002). Las alteraciones foliculares encontradas representan una vía más que piroxicam y otros AINE utilizan para inhibir la ovulación reportada con frecuencia en tratamientos con este tipo de fármacos.
Dinámicas de transferencia tecnológica en una universidad pública regional. El caso de la Universidad del Bío-Bío
Authors: García Llanos Fernando Esteban , Aguilera Cristhian , Catalán Pablo
Published: July 2016

Durante las últimas décadas, Chile ha experimentado un significativo crecimiento, resultando ello en un mayor bienestar socio-económico para su población. Sin embargo, su éxito se ve ensombrecido por diversos factores, principalmente su elevada desigualdad de ingresos, su excesiva centralización institucional y su baja capacidad de innovación. En este respecto, la transferencia tecnológica ha seguido una tendencia similar: el país no ha alcanzado, a pesar de su nueva riqueza, estándares internacionales, postergando de esta forma su entrada a la economía del conocimiento. El presente artículo tiene como objetivo analizar y explorar las dinámicas de transferencia tecnológica en una universidad pública y regional en Chile: la Universidad del Bío-Bío (UBB). La metodología utilizada considera herramientas cuantitativas y cualitativas, aplicando primero un modelo logit, para luego desarrollar, tres estudios de casos sobre proyectos de Investigación y Desarrollo (I+D) en UBB. El modelo a testear define como variable dependiente la ocurrencia de transferencia tecnológica e incluye cuatro variables independientes: i) Financiamiento Público en I+D; ii) Capacidad de Investigación; iii) Estructuras de Soporte de la Universidad; y iv) Redes. Los resultados muestran que la transferencia tecnológica en UBB depende de la Capacidad de Investigación de la Universidad – particularmente del número de patentes solicitadas por  el investigador principal y el desempeño, por parte del investigador principal, como director de un Centro o Laboratorio de I+D– , además de Redes, en relación al capital social del equipo del proyecto.
Degradation of chlorpyrifos in contaminated soil by immobilized laccase
Authors: Wang Xin , Yao Meng , Liu Li , Cao Yu , Bao Jia
Published: July 2016

In the present study, the embedding-crosslinking method was used to immobilize fungal laccase, and to determine the suitable conditions for immobilization by measuring various activities of the immobilized laccase. In addition, the immobilized laccase was further employed to repair chlorpyrifos-contaminated soil, and then the degradation rates of chlorpyrifos were measured under different conditions. Based on the results, the appropriate conditions for the method of mbedding-crosslinking were found to be as follows: concentration of sodium alginate ? 3 %, concentration of glutaraldehyde ? 1 %, crosslinking time ? 6h, volume of crude laccase ? 60 ml, and immobilization time ? 4 h. After 48 h, the degradation rate of chlorpyrifos in soil could reach at least 70 % by the use of immobilized laccase that was prepared by the method of embedding-crosslinking under different environmental conditions.
Effect of the formulation parameters on the encapsulation efficiency and release behavior of p-aminobenzoic acid-loaded ethylcellulose microspheres
Authors: Mouffok Meryem , Mesli Abderrezzak , Abdelmalek Ilham , Gontier Etienne
Published: July 2016

In the current study, p-aminobenzoic acid-loaded ethylcellulose microspheres
were prepared under various conditions by solvent evaporation method (o/w).
This preparation was carried out with different p-aminobenzoic
acid:ethylcellulose (PABA:EC) ratios, stirring speed, surfactant nature and
concentration in order to investigate their effect on encapsulation
efficiency and drug release kinetics. Scanning Electron Microscopy (SEM)
studies showed spherical microspheres with a porous surface and different
structures. The mean diameter of Sauter (d32) of these microparticles is in
the range from 47 to 165 ?m with PVA and from 793 to 870 ?m with Tween 80 by
adjusting process parameters. However, the encapsulation efficiency varied
from 37.52 to 79.05 % suitable for the adjustment of a p-aminobenzoic acid
with pro-longed release. Microspheres were characterized by FTIR, DSC and
XRD. The release of cation of p-aminobenzoic acid was performed in simulated
gastric medium at pH 1.2 and 37?0.5?C by UV-VIS analysis to estimate its
content. The release data were best fitted to Higuchi model with high
correlation coefficient (r?) and the obtained values of n from
Korsmeyer-Peppas showed that the drug release follows the Fickian diffusion
mechanism.
Does debt ceiling and government shutdown help in forecasting the us equity risk premium?
Authors: Aye Goodness , Deale Frederick , Gupta Rangan
Published: July 2016

This article evaluates the predictability of the equity risk premium in the
United States by comparing the individual and complementary predictive power
of macroeconomic variables and technical indicators using a comprehensive set
of 16 economic and 14 technical predictors over a monthly out-ofsample period
of 1995:01 to 2012:12 and an in-sample period of 1986:01- 1994:12. In order
to do so we consider, in addition to the set of variables used in Christopher
J. Neely et al. (2013) and using a more recent dataset, the forecasting
ability of two other important variables namely government shutdown and debt
ceiling. Our results show that one of the newly added variables namely
government shutdown provides statistically significant out-of-sample
predictive power over the equity risk premium relative to the historical
average. Most of the variables, including government shutdown, also show
significant economic gains for a risk averse investor especially during
recessions.
The sustainability of current account in the presence of endogenous multiple structural breaks: Evidence from developed and developing countries
Authors: Dülger Fikret
Published: July 2016

The purpose of this study is to test for the sustainability of current
account in 18 developed and 10 developing countries. The stability of the
relationship between export (inflows) and import (outflows) is assessed using
the tests proposed by Mohitosh Kejriwal and Pierre Perron (2010). In
particular, the nature of the long-run relationship, when multiple regime
shifts are identified endogenously, is analyzed using the residual-based test
of the null hypothesis of cointegration with multiple breaks proposed by
Kejriwal (2008). The results clearly indicate that, for all countries, (i)
the stability tests reject the null of coefficient stability of the long-run
relationship between exports and imports; (ii) the cointegration tests that
correspond to the number of breaks selected reject the null of cointegration
(weak form of sustainability); and (iii) the strong form of sustainability
hypothesis is not supported by the data for all countries in most regimes but
not for 20 of 28 countries especially in the last regime (the post-2000
era). For eight countries (Canada, New Zealand, Spain, Brazil, Mexico, South
Africa, Thailand, and Turkey), the findings may be perceived as a warning to
creditors and policymakers unless there are policy distortions or permanent
productivity shocks to the domestic economies.
Capital structure in the global shipping industry
Authors: Paun Cristian , Topan Vladimir
Published: July 2016

The current economic crisis emerged from a particular financial crisis that
started in the United States and being rapidly propagated all over the world.
It did not affect a limited region or a limited economic sector. This crisis
induced significant changes in all management areas, including financial
management. This study is focused on financing strategies adopted by shipping
companies during the crisis, analyzing relevant factors for a specific issue
- the capital structure. The research methodology proposed for this analysis
on relevant factors that could explain the capital structure of shipping is
OLS regression applied on selected variables derived from the financial
statements of the major shipping companies. The dependent variables
reflecting capital structure are book value to total liabilities ratio and
book value to total debt ratio. The explanatory variables are derived from
the theory of capital structure. This study empirically illustrates the
relevance of the capital structure theory for the studied economic sector and
is a useful tool for the shipping companies, providing relevant information
about the optimal capital structure adopted by shipping companies and about
factors that influence this decision during a crisis period.
The presence of turnip yellows virus in oilseed rape (Brassica napus L.) in Serbia
Authors: Milosevic Dragana , Ignjatov Maja , Nikolic Zorica , Stankovic Ivana , Bulajic Aleksandra , Marjanovic-Jeromela Ana , Krstic Branka
Published: July 2016

A total of 86 oilseed rape samples from six crops in different localities
were collected during 2014 and analyzed for the presence of Turnip yellows
virus (TuYV), Cauliflower mosaic virus (CaMV) and Turnip mosaic virus (TuMV)
using commercial double-antibody sandwich (DAS)-ELISA kits. TuYV was
serologically detected in 60 collected samples (69.77%), and none of the
samples tested were positive for CaMV and TuMV. Six selected TuYV isolates
were successfully transmitted by Myzus persicae to three test plants,
confirming the infectious nature of the disease. In the selected
ELISA-positive samples, the presence of TuYV was further confirmed by RT-PCR
and sequencing. A comparison of the obtained sequence with those available in
GenBank confirmed the presence of TuYV in oilseed rape samples. An analysis
of P0 gene sequence data for a subset of these isolates showed they clustered
with the known TuYV and were distinct from Beet western yellows virus (BWYV)
isolates.
Field efficacy of different fungicide mixtures in control of net blotch on barley
Authors: Stepanovic Milos , Rekanovic Emil , Milijasevic-Marcic Svetlana , Potocnik Ivana , Todorovic Biljana , Stepanovic Jelena
Published: July 2016

Seven fungicide mixtures (epoxiconazol + metconazole, boscalid +
epoxiconazole, pyraclostrobin + epoxiconazole, prothioconazole +
tebuconazole, picoxistrobin + cyproconazole, azoxystrobin + cyproconazole
and spiroxamine + tebuconazole + triadimenol) were evaluated for control of
net blotch of barley caused by Drechslera teres, as well as yield losses,
over the 2010 and 2011 growing seasons. Two applications of the fungicide
combination pyraclostrobin + epoxiconazole at the rate of 1.0 l ha-1 were
the most effective treatment in controlling the disease and improving yield
in both experimental years. Treatments with the fungicide mixtures
epoxiconazol + metconazole and spiroxamine + tebuconazole + triadimenol
showed the least effectiveness in disease control, as well as yield
increase.
Integrated Information Systems, Alliance Formation, and the Risk of Information Exchange between Partners
Authors: Christ Margaret H. , Nicolaou Andreas I.
Published: July 2016

Alliances are an important strategic tool for many companies. However, they are inherently risky and a large percentage of alliances fail. We examine the effects of integrated information systems (IISs) and alliance formalization (i.e., formal alliance controls) on information exchange risk and overall alliance risk. We develop a model that predicts that when firms are engaged in alliances with greater collaboration intensity (i.e., alliances with multiple objectives) they are more likely to use an IIS and a broad portfolio of formal controls to manage alliance risk. Using a survey of chief financial officers, we find that collaboration intensity is positively associated with IIS and alliance formalization. IISs are negatively associated with information exchange risk, but this effect is mediated by alliance formalization, suggesting that the formal controls implemented throughout the alliance, and within the IIS, are integral to reducing information exchange risk and, subsequently, overall alliance risk. Our study adds to the literature examining tools and strategies for effectively managing strategic alliances.

JEL Classifications: B20; C31; C42; M40.
Standardized Mixed-Meal Tolerance and Arginine Stimulation Tests Provide Reproducible and Complementary Measures of β-Cell Function: Results From the Foundation for the National Institutes of Health Biomarkers Consortium Investigative Series
Authors: Shankar Sudha S. , Vella Adrian , Raymond Ralph H. , Staten Myrlene A. , Calle Roberto A. , Bergman Richard N. , Cao Charlie , Chen Danny , Cobelli Claudio , Dalla Man Chiara , Deeg Mark , Dong Jennifer Q. , Lee Douglas S. , Polidori David , Robertson R. Paul , Ruetten Hartmut , Stefanovski Darko , Vassileva Maria T. , Weir Gordon C. , Fryburg David A.
Published: July 2016

OBJECTIVE

Standardized, reproducible, and feasible quantification of β-cell function (BCF) is necessary for the evaluation of interventions to improve insulin secretion and important for comparison across studies. We therefore characterized the responses to, and reproducibility of, standardized methods of in vivo BCF across different glucose tolerance states.

RESEARCH DESIGN AND METHODS

Participants classified as having normal glucose tolerance (NGT; n = 23), prediabetes (PDM; n = 17), and type 2 diabetes mellitus (T2DM; n = 22) underwent two standardized mixed-meal tolerance tests (MMTT) and two standardized arginine stimulation tests (AST) in a test-retest paradigm and one frequently sampled intravenous glucose tolerance test (FSIGT).

RESULTS

From the MMTT, insulin secretion in T2DM was >86% lower compared with NGT or PDM (P < 0.001). Insulin sensitivity (Si) decreased from NGT to PDM (∼50%) to T2DM (93% lower [P < 0.001]). In the AST, insulin secretory response to arginine at basal glucose and during hyperglycemia was lower in T2DM compared with NGT and PDM (>58%; all P < 0.001). FSIGT showed decreases in both insulin secretion and Si across populations (P < 0.001), although Si did not differ significantly between PDM and T2DM populations. Reproducibility was generally good for the MMTT, with intraclass correlation coefficients (ICCs) ranging from ∼0.3 to ∼0.8 depending on population and variable. Reproducibility for the AST was very good, with ICC values >0.8 across all variables and populations.

CONCLUSIONS

Standardized MMTT and AST provide reproducible and complementary measures of BCF with characteristics favorable for longitudinal interventional trials use.
The Influences of Cutting Temperature on the Filling Value of Cut Tobacco and on the Compressibility of Cigarettes / Der Einfluss verschiedener Temperaturen beim Schneiden von Blattabak auf das Füllvermögen von Schnittabak und die Kompressibilität von Cigaretten
Authors: Smit H.
Published: July 2016

The influences of the cutting temperature on the filling value and elasticity of a bright blend as well as on the compressibility and elasticity of cigarettes made of the same blend are investigated. A low cutting temperature of about 25°C (as against 40°C) gives a more elastic cut tobacco presenting a better filling value. Cigarettes made with cold cut tobaccos have clearly less compressibility and elasticity, i.e. they are more compact. The distribution of strand dimensions remains unchanged in the two cutting temperatures. In neither case is there any tendency towards sticking
Determination of the Properties of French Tobaccos / Systematische Untersuchung der Kennwerte der französischen Tabake
Authors: Pietrucci A.
Published: July 2016

Every year the Regie Française specifies the properties of the French tobaccos harvested for the current production. The author describes procedures and practical measures by which the filling value of the different tobacco samples composed at the planters' when purchased is determined
The Function of Nucleonic Controllers in Cigarette Machines - Über die Auswirkungen von nukleonischen Steuerungen an Cigarettenstrangmaschinen
Authors: Marek J. , Hayn G.
Published: July 2016

The function of nucleonic controllers in cigarette machines is briefly described. Improvements in the quality of the final product brought about by application of the system as well as resulting economic profits are examined. The efficiency of the protective screen against radiation is discussed
Examination of the Gas-Vapour Phase of Tobacco Smoke. 1. Report: An Apparatus for the Absorption of Aerosoles, Vapours and Gases in Liquids / Zur Untersuchung der Gas-Dampf-Phase des Cigarettenrauches. 1. Mitteilung: Der Rotations-Abscheider, ein Gerät zur Absorption von Aerosolen, Dämpfen und Gasen in Flüssigkeiten
Authors: Barkemeyer H.
Published: July 2016

An apparatus for the absorption of tobacco smoke in liquids and particularly for the absorption of the gas-vapour phase of tobacco smoke is described. The depicted procedure enables the collection of representative mean samples for analytical purposes in one smoking process
The Selective Effect of Cigarette Filters on the Nicotine and Phenol Retention in Different Tobacco Types / Über die selektive Wirkung von Cigarettenfiltern auf Nikotin und Phenole sowie ihre Abhängigkeit von der Tabaksorte
Authors: Lipp G.
Published: July 2016

The dependence of the nicotine and phenol retention by filters made of cellulose and cellulose acetate upon the type of tobacco or tobacco mixture, upon the hydrogen ion concentration of the smoke, and upon tobacco additives which are apt to modify the reaction of the smoke is presented. The investigations centre in the circumstances under which nicotine can selectively be retained by a filter. Furthermore the distribution of nicotine and phenols within the filter is studied. It is shown that the coefficient of filtration of these substances is not constant but obviously diminishes with the length and predominantly in the first 10 mm of the fore-part of the filter
The Selective Retention of Phenol by Cigarette Filter Materials
Authors: Roux J. H. le
Published: July 2016

A method is described for the study of the abilities of different substances to r~move phenol from a gas stream, with application to the selective filtration of tobacco smoke in mind. Use was made .of ,gas chromatography, measuring the retention time of phenol on columns containing different materials. Differences in the mechanism through which phenol is retained by pure and plasticized cellulose acetates became apparent. A number of substances expected to give hydrogen bonding with phenol were added to the usual cigarette filter materials. Considerable increase in phenol retention was only found in the cases of urea and nicotinamide
Trapping and Analysis of the Gas Phase of Cigarette Smoke/Zur Gewinnung und Behandlung frischer Gasphase aus Cigarettenrauch
Authors: Grob K.
Published: July 2016

The gaseous part of cigarette smoke was brought into contact with the surfaces of different materials such as glass, stainless steel, silicone rubber, and condensed gas phase. Subsequent analysis by gaschromatography shows that the gas phase may be even less stable than is generally assumed. Inert as well as reactive components are reduced by a short surface contact, the former up to 50, the latter up to 300 %. Using a specially designed large syringe made of teflon and steel we observed the lowest loss of smoke constituents caused by trapping the gas phase at room temperature.
N-Nitroso Compounds in Tobacco Smoke II/Zur Frage der N-Nitroso-Verbindungen im Tabakrauch ll
Authors: Neurath G. , Pirmann B. , Lüttich W. , Wichern H.
Published: July 2016

The cold pentane traps of the precipitation procedure described in the preceding paper (cotton wool trap, water trap, pentane traps) favour the formation of N-nitroso components and, as a result, the emergence of artefacts. If, however, the smoke sojourns in the aerosol state for a period of 40 seconds (compared to 5 seconds) also that part of condensate of smoke from cigarette tobaccos rich in nitrates and bases which is trapped on cotton wool at normal temperature, contains N-nitroso-dimethylamine and N-nitroso-pyrrolidine in quantities corresponding to 0.004 µg N-NO per cigarette. The formation of N-nitroso components in the smoke of tobaccos of high nitrate and base contents accordingly occurs during a gas phase reaction which is dependent on time.

In conformity with the previously reported findings N-nitrosomethyl-n-butylamine was identified in the condensate gathered in pentane traps. Presumably, it has however to be regarded as an artefact produced by the precipitation system employed. Condensates collected in cold and acetone traps were found to contain more N-nitroso components than condensates precipitated simply by the gas phase reaction of the smoke. The quantity of N-nitroso components contained in condensates gathered in cold traps was found to increase during aging.

Model experiments with pure substances showed that the formation of N-nitroso components in the gas phase requires the presence of a mixture of NO and NO

The competitive reaction of dimethylamine and methanol with the gaseous mixture of nitrogen oxides displays the prevailing formation of N-nitroso-dimethylamine. The yield of N-nitroso-dimethylamine in NO-air-mixtures is probably only dependent on the rate of the oxidation NO undergoes to NO

Nitramines cannot occur in smoke.
Methods of Quantitative Determination of Catechol in Cigarette Smoke Condensate/Methoden der quantitativen Bestimmung des Brenzcatechins im Cigarettenrauch
Authors: Waltz P. , Häusermann M. , Krull A.
Published: July 2016

Three methods of quantitative determination of catechol in cigarette smoke condensate are presented. The procedures are based on:

a.Column chromatography of a smoke condensate solution in chloroform over polyamide powder, followed by elution with ethyl acetate and a spectrophotometric measure in methanol solution;

b.Liquid-liquid partitions of the smoke condensate, followed by a spectrophotometric measure based on a bathochromic shift of the absorption spectrum of catechol; and

c.Vapour-phase chromatography of the phenolic smoke components in the form of their methyl ethers. The procedure a. is best suited as a routine method, as it is easy to execute and gives fairly accurate and precise results. The procedures b. and c. both give less reproducible results, and c. shows insufficient analytical yields. Their advantages are the rapid execution of method b. and the high specificity of method c.

Contents between 200 and 500 µg of catechol per cigarette were found in the smoke of cigarettes.
An Automatic Capillary Press, a Smoking Machine for Collecting Instant Smoke Condensate. 2nd Report: An Automatic Capillary Press/Die Kapillarpresse, eine Rauchmaschine zur Gewinnung von nativem Rauchkondensat. 2. Mitteilung: Die automatische Kapillarpresse
Authors: Seehofer F. , Hanssen D.
Published: July 2016

Construction and working principle of an automatic capillary press, a smoking machine for preparing instant smoke condensate of 15 cigarettes per smoking procedure, are presented. The smoking capacity is 500 cigarettes per day. Condensate production by means of total puffs smoking, in echelons as well as by means of individual puffs is possible. The reproducibility of smoke condensate and smoke nicotine yields is 2.5% R.S.D. Compared with electrostatic precipitation the smoke yield is 90%. The yields of condensate, nicotine, phenols, water, acids, and benzopyrene are reported. Changes of the results of total puffs yields and individual puff yields as a function of initial tobacco moisture as well as different precipitation procedures are indicated.
Total Water Content of Mainstream Smoke and Sidestream Smoke / Über den Wassergehalt von Haupt- und Nebenstromrauch
Authors: Neurath G. , Ehmke H. , Schneemann H.
Published: July 2016

The present paper gives a balance of total water (comprising moisture content of tobacco as well as water of combustion) in the smoking of a plain cigarette without filter under standard conditions. 62.8 % of the hydrogen originally present in the burnt portion of the cigarette are transformed into water. The sidestream smoke is enriched by the total water to a large extent, i.e., in proportion to the total water of a cigarette, 14.4 mg of water are calculated to be transferred to the mainstream smoke and 344.7 mg to the sidestream smoke and to the ashes. 14.6 % of the said hydrogen are found to be delivered into the condensates of main and sidestream smoke in the form of slightly volatile compounds containing hydrogen. The residual 22.6 % are transferred into the gas-vapour phase in the form of volatile compounds. The interpretation of temperature measurements made along the axis of and in the space above a freely smouldering cigarette (without drawing) as well as the determination of the velocity (33 cm/sec) of the escaping sidestream smoke indicate the presence of a rapid and steep convection stream over the glowing zone. This finding accounts for the large water enrichment of the sidestream smoke and for the fact that water formed by the combustion process does not contribute to the transfer of steam-volatile substances into the sidestream smoke.
A Capillary Press, a Smoking Machine for the Collection of Native Smoke Condensate. 3rd Report: An Automatic Smoking Machine Equipped with a Supplementary Appliance for Free and Restricted Smoking / Die Kapillarpresse, eine Rauchmaschine zur Gewinnung von nativem Rauchkondensat. 3. Mitteilung: Die automatische Kapillarpresse mit einem Rauchkopf für offenes oder geschlossenes Abrauchen
Authors: Seehofer F. , Hanßen D.
Published: July 2016

A supplementary appliance for free and restricted smoking has been developed for the ''capillary press'' smoking machine. The principle of the instrument is also applicable to the automatic smoking machine for rapid series analyses (BAT). The device permitted to examine to what extent smoke yields obtained by free and restricted smoking vary as a function of initial moisture content, puff order, butt length, and the pressure drop of the filter. The yields produced by "capillary press" free smoking of cigarettes whose initial moisture content was 12 % were found to exceed the corresponding yields obtained by restrictive smoking of the same cigarettes by the following proportions; phenols: up to 38 %, nicotine: up to 32 %, mainstream smoke condensate: up to 17 %, and benzo[a]pyrene: up to 13 %. The differences in smoke yields decreased continuously with augmenting initial moisture content (5 to 20 %). Extreme increase of pressure drop (for example by means of filters) resulted in almost complete compensation of the effect of free smoking. Increased retention efficiency of the filter (measured by the indirect method) was simulated.
Electric Polarity of Cigarette Mainstream Smoke / Die elektrischen Ladungen des Hauptstromrauches von Cigaretten
Authors: Erxleben E. , Janke K. , Neurath G.
Published: July 2016

The electric polarity of cigarette mainstream smoke depending on the remaining length of the cigarette was determined using two different devices. Furthermore the concentrations of positive and negative charges in the smoke were dimensionally measured. The results show that positive as well as negative charges are existent in mainstream smoke with about the same concentration of 10
The Distribution of the Air Flow through a Cigarette / Die Verteilung des Ventilationsstromes auf einer Cigarette
Authors: Meyer-Abich K.M.
Published: July 2016

The distribution of the air flow through the porous wrapping of a cigarette is

ν (λ, l) being the density of the air flow (cm3 sec-1 cm-1) on the paper wrapping at the position l if l is the length of the porous paper wrapping between the non-porous tip and the burning cone and l is the distance of the position in question from the non-porous tip. ν (λ, l) is given in air flow per cm rather than in air flow per cm2 because of the cylindrical shape of the cigarette. I denotes the total stream at the mouth piece, a is the specific conductivity to air flow of the paper wrapping, b is the specific resistance to air flow of the tobacco rod, RG is the resistance to air flow of the burning cone [compare (1)]. The formula is derived and discussed. The dependence of the distribution of the ventilation stream on the length l and on the resistance RG is demonstrated for the case of a formerly investigated cigarette rod (1). The gradient of ν (λ, l) is

so that the density of the ventilation stream through the paper wrapping decreases almost linearly from its maximum at the tip to its minimum at the burning cone if the degree of ventilation is low, i.e. if the air flow I (λ, l) in the cigarette is not much higher at λ = 0 than at λ = l
Evaluation of Normal, Branched Paraffin Hydrocarbons and Some Unsaturated Aliphatic Hydrocarbons in Cigarette Smoke by Glass Capillary Columns
Authors: Carugno N. , Rossi S.
Published: July 2016

Gas chromatographic analyses of normal and branched paraffin hydrocarbons of cigarette smoke condensate were performed with SE 52 coated glass capillary columns using a flame ionization detector and working in isotherm temperature and in linear programmed temperature. This investigation was extended to fractions containing unsaturated aliphatic hydrocarbons, by using in this case both an electron capture detector and a flame ionization detector. Some chromatograms are reported.
The Effect of Different Puff Profiles on Yield and Composition of Mainstream Smoke of Cigarettes Smoked on a Smoking Machine/Einfluss verschiedener Zugvolumenprofile auf Ausbeute und Zusammensetzung des Rauches beim maschinellen Abrauchen von Cigaretten
Authors: Seehofer F. , Wennberg D.
Published: July 2016

A study was made of the effect of the puff profile on yield and composition of the mainstream smoke of cigarettes smoked on a RM 20/68 smoking machine producing three different puff profiles (square-shaped profile, early peak and late peak profiles). The smoke was precipitated in an electrostatic trap. Crude condensate, dry condensate, smoke nicotine, phenols, puff number, and draw resistance were determined. Significant differences were found between the dry condensate yields of two puff profiles and between the nicotine and phenol yields of all the three puff profiles.
Automatic Dropping-Applicator for Epicutaneous Tests with Mice in Combination with a Capillary Press - Applikationsautomatik für Epikutanversuche an Mäusen als Zusatzgerät zur Seehofer'schen Kapillarpresse
Authors: Brune H. , Burghart H.
Published: July 2016

An automatic dropping-applicator for fresh cigarette smoke condensate is described. The new applicator makes it possible to apply separately a solvent and the smoke condensate produced by a capillary press. 15 animals can be treated simultaneously
Chromatographic Examinations on the Separation of the Alkylating Fractions of Cigarette Tobacco and Smoke/Chromatographische Untersuchungen zur Auftrennung alkylierender Fraktionen des Cigarettentabaks und des Cigarettenrauches
Authors: Norpoth K. , Papatheodorou T. , Venjakob G.
Published: July 2016

In order to obtain information about number and origin of compounds which may contribute to the alkylating activity of tobacco smoke condensate identifiable in the methanol extract of the condensate of commerciaI cigarettes by means of 4-(4'-nitrobenzyI)pyridine, spectroscopic as well as thin-layer- and column-chromatographic procedures were used. Two compounds of the water- or methanoI-soluble fraction were separated and proved to be resorbed during inhalation and dissolved in saliva. During the process of conventional condensate treatment, further five less polaric compounds were found to remain in the cyclohexane fraction, whereas the resulting nitromethane fraction contains the carcinogenic activity almost totally. These compounds can also be extracted from unsmoked tobacco. The role they possibly play in respiratory carcinogenesis is discussed on the basis of the results obtained by the present study with regard to carcinogenic constituents of tobacco extracts.
Composition Studies on Tobacco: XLV. Use of Cigarette Additives to Alter the Composition and Reducing Properties of Cigarette Smoke
Authors: Lakritz L. , Strange E.D. , Bailey D.G. , Stedman R.L.
Published: July 2016

The reducing potential of fresh cigarette smoke can be modified by the use of certain oxidants and reductants. The influence of these additives on smoke may be monitored by employing a system which measures changes in EMF on a puff by puff basis. The addition of the oxidant 1,4-benzoquinone to tobacco eliminates the rapid reduction in potential which normally takes place when an untreated cigarette is smoked. The addition of the benzoquinone alters the composition of the smoke by increasing the levels of the total particulate matter and possibly the phenols, while decreasing the nicotine content without affecting the amount of benzo[a]pyrene formed. The addition of sodium thiosulfate to tobacco causes a significant increase in the reducing capacity of cigarette smoke. It also brings about increases in the smoke BAP, phenols and TPM. The level of nicotine in these cigarettes, however, is lowered.
The Determination of Menthol in Tobacco, in Filters and in the Smoke of Mentholated Cigarettes/Untersuchungen über die Verteilung des Menthols auf Tabak, Filter und Rauch von Mentholcigaretten
Authors: Brozinski M. , Dölberg U. , Lipp G.
Published: July 2016

A method for the determination of menthol in tobacco, in filters before and after smoking as well as in the smoke of mentholated cigarettes is presented which is based on the combination of steam distillation and liquid-Iiquid partition followed by gas chromatography on polypropylene glycol in the presence of benzylpropionate as an internal standard. The procedure also permits menthone to be quantitatively determined as a characteristic constituent of peppermint oils. Analytical results concerning reproducibility, recovery and sensitivity of the method are detailed. The transfer of menthol from the tobacco rod to the acetate filter and vice versa as a function of the storing period of mentholated cigarettes has been investigated as well as the menthol distribution due to the smoking process. A considerable selective retention of menthol by cellulose acetate filters could be demonstrated. Various mentholated cigarettes of different origin and of different menthol contents have comparatively been analysed.
Characteristic Products from Pyrolysis of Nitrogenous Organic Substances
Authors: Schmeltz I , Schlotzhauer W.S. , Higman E.B.
Published: July 2016

The products resulting from the pyrolysis of tobacco and a number of nitrogenous organic compounds similar, if not identical, to those found in tobacco have been compared. Similarities have been noted in the composition of the various pyrolyzates, but essentially no physiologically active materials were found. Generalities with regard to pyrolysis of nitrogenous organic substances have been suggested by the data assembled.