18,839 research outputs found
Generalized retarded integral inequalities
We prove some new retarded integral inequalities. The results generalize
those in [J. Math. Anal. Appl. 301 (2005), no. 2, 265--275].Comment: Changes suggested by the referee don
Economic analysis of royalactin production under uncertainty: Evaluating the effect of parameter optimization.
Royalactin is a protein with several different potential uses in humans. Research, in insects and in mammalian cells, has shown that it can accelerate cell division and prevent apoptosis. The method of action is through the use of the epidermal growth factor receptor, which is present in humans. Potential use in humans could be to lower cholesterolemic levels in blood, and to elicit similar effects to those seen in bees, e.g., increased lifespan. Mass production of Royalactin has not been accomplished, though a recent article presented a Pichia pastoris fermentation and recovery by aqueous two-phase systems at laboratory scale as a possible basis for production. Economic modelling is a useful tool with which compare possible outcomes for the production of such a molecule and in particular, to locate areas where additional research is needed and optimization may be required. This study uses the BioSolve software to perform an economic analysis on the scale-up of the putative process for Royalactin. The key parameters affecting the cost of production were located via a sensitivity analysis and then evaluated by Monte Carlo analysis. Results show that if titer is not optimized the strategy to maintain a low cost of goods is process oriented. After optimization of this parameter the strategy changes to a product-oriented and the target output becomes the critical parameter determining the cost of goods. This study serves to provide a framework for the evaluation of strategies for future production of Royalactin, by analyzing the factors that influence its cost of manufacture. © 2015 The Authors Biotechnology Progress published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers Biotechnol. Prog., 2015
Characterization and optimization of polymer-polymer aqueous two-phase systems for the isolation and purification of CaCo2 cell-derived exosomes
Exosomes are cell-derived vesicles that present attractive characteristics such as nano size and unique structure for their use as drug delivery systems for drug therapy, biomarkers for prognostic, diagnostic and personalized treatments. So far, one of the major challenges for therapeutic applications of exosomes is the development of optimized isolation methods. In this context, aqueous two-phase systems (ATPS) have been used as an alternative method to isolate biological molecules and particles with promising expectations for exosomes. In this work, fractionation of exosomes obtained from CaCo2 cell line and culture media contaminants were individually performed in 20 polymer-polymer ATPS. The effect of design parameters such as polymer composition, molecular weight, and tie-line length (TLL) on polyethylene glycol (PEG)-Dextran, Dextran-Ficoll and PEG-Ficoll systems was studied. After partition analysis, 4 of the 20 systems presented the best exosome fractionation from contaminants under initial conditions, which were optimized via salt addition (NaCl) to a final concentration of 25 mM, to improve collection efficiency. The PEG 10,000 gmol-1 –Dextran 10,000 gmol-1 system at TLL 25% w/w with NaCl, showed the best potential isolation efficiency. Following this proposed strategy, an exosome purification factor of 2 in the top PEG-rich phase can be expected furtherly demonstrating that ATPS have the potential for the selective recovery of these promising nanovesicles
The prehistoric individual, connoisseurship and archaeological science: The Muisca goldwork of Colombia
Unlike art historians, archaeologists rarely make systematic attempts at attributing artefacts to individual artisans - they stop at the broader category of 'provenance regions' or 'technical styles'. The identification of archaeological individuals, however, allows detailed insight into the organisation of workshops, knowledge transmission, skill, and the tension between individual and social agency. This paper reviews the potential of archaeological science methods to identify individual artisans through the study of material culture. Focusing on the Muisca votive goldwork of Colombia, it combines stylistic, chemical and microscopic analyses to identify idiosyncratic motor habits, material selections and artistic preferences that allow the identification of individual makers and manufacturing events. The results are informative of the internal dynamics between the Muisca technological tradition, religious behaviour and craft specialists. We conclude by outlining the potentials and challenges of science-based archaeological connoisseurship in other contexts
New objects in old structures: The Iron Age hoard of the Palacio III megalithic funerary complex (Almadén de la Plata, Seville, Spain)
Cultural contact, exchange and interaction feature high in the list of challenging topics of current research on European Prehistory. Not far off is the issue of the changing role of monuments in the making and maintaining of key cultural devices such as memory and identity. Addressing both these highly-debated issues from a science-based perspective, in this paper we look at an unusual case study set in southern Iberia and illustrate how these archaeological questions can benefit from robust materials-science approaches.We present the contextual, morphological and analytical study of an exceptional Early Iron Age hoard composed of a number of different (and mostly exotic) materials such as amber, quartz, silver and ceramic. This hoard, found under the fallen orthostat of a megalithic structure built at least 2000 years earlier, throws new light on long-distance exchange networks and the effect they could have had on the cultural identities and social relations of local Iberian Early Iron Age communities. Moreover, the archaeometric study reveals how diverse and distant the sources of these item are (Northern Europe to Eastern and Western Mediterranean raw materials, as well as local and eastern technologies), therefore raising questions concerning the social mechanisms used to establish change and resistance in contexts of colonial encounter
Primordial Nucleosynthesis as a test of variable rest masses 5-dimensional cosmology
The deviation of primordial Helium production due to a variation on the
difference between the rest masses of the nucleons is presented. It is found an
upper bound \delta (M_{_n} - M_{_p}) \alt 0.129 MeV, between the present and
nucleosynthesis epochs. This bound is used to analyze Wesson's theory of
gravitation; as a result, it is ruled out by observation.Comment: Corrected version with referee's remarks. Unchanged global results.
Some references added; to be published in Phys. Lett. A
Oral Cancer Screening Habits Performed by Registered Dental Hygienists
The purpose of this study was to assess if registered dental hygienists perform thorough and complete extraoral and intraoral assessments for cancer detection through the use of palpation techniques, visualization and adjunctive screening devices. Our goal was to assess if these exams are being performed routinely and thoroughly, and if not, what possible barriers to regular exams may exist. This study will determine if registered dental hygienists perform thorough and complete extra oral and intra oral assessments for cancer detection. If there is a lack of performance of extra oral and intra oral assessments, it is essential to determine the barriers that are preventing the hygienist from performing them. This information will be generalizable to all RDH’s
Estudio del yeísmo en el español de Barcelona a partir de materiales de PRESEEA
En enero de 2006, el equipo de investigación sociolingüística de la Universidad de
Barcelona, integrado por profesores y doctorandos del Departamento de Filología
Hispánica, se incorporó al Proyecto para el Estudio Sociolingüístico del Español de
España y de América (PRESEEA), vinculado a la Asociación de Lingüística y Filología
de América Latina (ALFAL), y que tiene como coordinador general a Francisco
Moreno Fernández, Catedrático de Lengua Española de la Universidad de Alcalá. Dicho
proyecto se organiza en una red internacional de equipos de investigación cuyo objetivo
central es el de reunir un ingente corpus oral, sociolingüísticamente representativo, de
un gran número de ciudades pertenecientes al mundo hispánico. La primera fase del
proyecto, que se presentó en 1996, abarca hasta el año 2010 (Moreno Fernández 2006).1
Para el estudio de Barcelona, en el seno del grupo PRESEEA – BARCELONA – ES
diseñamos una plantilla que contempla una representación de 108 informantes (los
cuales deben haber nacido en la ciudad, haber llegado a ella antes de cumplir los diez
años o llevar viviendo en el lugar más de veinte), distribuidos en tres variables de
preestratificación: sexo, edad y nivel de instrucción. A este perfil general añadimos la
variable ‘lengua primera’ (catalán / español), vista la repercusión que alcanza la
convivencia de las dos lenguas en la ciudad (Torres 2007).
En las páginas que siguen, nos proponemos abordar el avance real del yeísmo en la
Ciudad Condal a partir de unas muestras seleccionadas de los datos de PRESEEABARCELONA-
ES. El trabajo, que básicamente es de carácter fonético y presenta un
análisis acústico centrado en aspectos frecuenciales, de duración y de intensidad de las
muestras mencionadas, pretende ser un primer acercamiento al estadio en el que se encuentra el fenómeno en esta área específica
MAKING TECHNOLOGIES WORK IN RURAL COMMUNITIES: THE CASE OF FLATBED DRYER APPROPRIATION IN STO. DOMINGO, NUEVA ECIJA, PHILIPPINES
This paper aimed to explain how rice farmers in Sto. Domingo, Nueva Ecija, Philippines managed to properly appropriate flatbed dryers. It also sought to describe the modes of appropriation offlatbed dryers: adoption, adaptation, and peer/group learning. Data were gathered through a survey among 131 rice farmers and key informant interviews. Findings revealed that the rice farmers experimented and modified the features of flatbed dryers to better adapt the technology to their needs. The rice farmers have encountered problems in using the technology but have managed to employ adaptation strategies to address these problems which resulted to peer/group learning among them
A slip-based model for the size-dependent effective thermal conductivity of nanowires
The heat flux across a nanowire is computed based on the Guyer-Krumhansl
equation. Slip conditions with a slip length depending on both temperature and
nanowire radius are introduced at the outer boundary. An explicit expression
for the effective thermal conductivity is derived and compared to existing
models across a given temperature range, providing excellent agreement with
experimental data for Si nanowires
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