1,871 research outputs found
Robotic Extrusion of Algae-Laden Hydrogels for Large-Scale Applications
A bioprinting technique for large‐scale, custom‐printed immobilization of microalgae is developed for potential applications within architecture and the built environment. Alginate‐based hydrogels with various rheology modifying polymers and varying water percentages are characterized to establish a window of operation suitable for layer‐by‐layer deposition on a large scale. Hydrogels formulated with methylcellulose and carrageenan, with water percentages ranging from 80% to 92.5%, demonstrate a dominant viscoelastic solid–like property with G′ > G″ and a low phase angle, making them the most suitable for extrusion‐based printing. A custom multimaterial pneumatic extrusion system is developed to be attached on the end effector of an industrial multiaxis robot arm, allowing precision‐based numerically controlled layered deposition of the viscous hydrogel. The relationship between the various printing parameters, namely air pressure, material viscosity, viscoelasticity, feed rate, printing distance, nozzle diameter, and the speed of printing, are characterized to achieve the desired resolution of the component. Printed prototypes are postcured in CaCl2 via crosslinking. Biocompatibility tests show that cells can survive for 21 days after printing the constructs. To demonstrate the methodology for scale‐up, a 1000 × 500 mm fibrous hydrogel panel is additively deposited with 3 different hydrogels with varying water percentages
FRECUENCIA DEL USO DEL ANTICONCEPTIVO ORAL DE EMERGENCIA Y SUS REPERCUSIONES EN LA SALUD de las alumnas de la Universidad Alas Peruanas Puerto Maldonado- Marzo-Mayo, 2012
Objetivo: Conocer como la frecuencia de uso del anticonceptivo oral de emergencia (AOE), repercute en la salud de las alumnas de la Universidad Alas Peruanas-Puerto Maldonado, marzo-mayo del 2012. Material y métodos:Se trabajó con una población de 60 alumnas usuarias y el muestreo fue intencionado. Es una investigación de tipo Descriptivo, no experimental y de corte transversal. Resultados:El 33.0% de la muestra tienen 19 años a más seguidos de los que tienen 18 años (29.6%). Respecto a la religión el 100% son creyentes. Saben lo que es la AOE, el 42.85% de las usuarias obtuvo la información del internet y en menor % la obtuvieron de la pareja y propaganda televisiva. El 71.42% de las usuarias manifiesta que tienen conocimiento de los efectos Secundarios y conocen la dosificación. La frecuencia en el uso de AOE de los últimos 6 meses el 76.20% ha hecho uso de ella, 14 usuarias manifiestan haberla tomado de 1 a 3 veces. La frecuencia del uso de AOE en periodo de un año el 90.47% manifiesta que si la uso, de estas usuarias el 84.21% refiere que la uso de 1 a 3 veces.Dentro de las repercusiones en la salud el síntoma que se presentó con más frecuencia fue el dolor de cabeza (32%) seguido de las náuseas (28%), hinchazón de mamas (12%), secreción blanquecina (12%), y menstruación adelanta un 4%, frente a un 12% que no presento ningún síntoma.Conclusiones:La mayoría de usuarias son adolescentes tardías (18,19 años). En su totalidad son creyentes, y conocen la dosificación de la AOE. La frecuencia de uso es elevada y Dentro de las repercusiones en la salud el síntoma que se presentó con más frecuencia fue el dolor de cabeza, náuseas, hinchazón de mamas, secreción blanquecina, y menstruación adelantada.La frecuencia elevada de AOE ocasiona efectos colaterales no deseados, en las usuarias. Palabras clave: Anticoncepción oral de emergencia, repercusiones en la salud
Optimized Planar Penning Traps for Quantum Information Studies
A one-electron qubit would offer a new option for quantum information
science, including the possibility of extremely long coherence times.
One-quantum cyclotron transitions and spin flips have been observed for a
single electron in a cylindrical Penning trap. However, an electron suspended
in a planar Penning trap is a more promising building block for the array of
coupled qubits needed for quantum information studies. The optimized design
configurations identified here promise to make it possible to realize the
elusive goal of one trapped electron in a planar Penning trap for the first
time - a substantial step toward a one-electron qubit
A constitutive law for dense granular flows
A continuum description of granular flows would be of considerable help in
predicting natural geophysical hazards or in designing industrial processes.
However, the constitutive equations for dry granular flows, which govern how
the material moves under shear, are still a matter of debate. One difficulty is
that grains can behave like a solid (in a sand pile), a liquid (when poured
from a silo) or a gas (when strongly agitated). For the two extreme regimes,
constitutive equations have been proposed based on kinetic theory for
collisional rapid flows, and soil mechanics for slow plastic flows. However,
the intermediate dense regime, where the granular material flows like a liquid,
still lacks a unified view and has motivated many studies over the past decade.
The main characteristics of granular liquids are: a yield criterion (a critical
shear stress below which flow is not possible) and a complex dependence on
shear rate when flowing. In this sense, granular matter shares similarities
with classical visco-plastic fluids such as Bingham fluids. Here we propose a
new constitutive relation for dense granular flows, inspired by this analogy
and recent numerical and experimental work. We then test our three-dimensional
(3D) model through experiments on granular flows on a pile between rough
sidewalls, in which a complex 3D flow pattern develops. We show that, without
any fitting parameter, the model gives quantitative predictions for the flow
shape and velocity profiles. Our results support the idea that a simple
visco-plastic approach can quantitatively capture granular flow properties, and
could serve as a basic tool for modelling more complex flows in geophysical or
industrial applications.Comment: http://www.nature.com/nature/journal/v441/n7094/abs/nature04801.htm
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Urinary incontinence related to perineal muscle strength in the first trimester of pregnancy: cross-sectional study
Objective To analyze pelvic floor muscle strength (PFMS), urinary continence and quality of life related to urinary incontinence (UI) of women in the first trimester of pregnancy. Method Cross-sectional study with a sample of 500 women who started prenatal care in a complementary healthcare facility in Guarulhos, state of São Paulo, from 2012 and 2013. Pelvic floor muscle strength was evaluated through perineometry. The pregnant women who presented UI answered the International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF). Results It was found that maternal age (OR=1.06; CI95% 1.02-1.11) and prior UI (OR=15.12; 95%CI 8.19-27.92) are the variables that, in tandem, best explain the occurrence of UI at the beginning of pregnancy. The mean score on the ICIQ-SF was 8.2 (SD=3.9), considered a moderate impact on quality of life. Conclusion Older pregnant women with prior UI are more likely to have UI in the first trimester of pregnancy.
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Women’s pelvic floor muscle strength and urinary and anal incontinence after childbirth: a cross-sectional study
Abstract OBJECTIVE To analyse pelvic floor muscle strength (PFMS) and urinary and anal incontinence (UI and AI) in the postpartum period. METHOD Cross-sectional study carried out with women in their first seven months after child birth. Data were collected through interviews, perineometry (Peritron™), and the International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF). RESULTS 128 women participated in the study. The PFMS mean was 33.1 (SD=16.0) cmH2O and the prevalence of UI and AI was 7.8% and 5.5%, respectively. In the multiple analyses, the variables associated with PFMS were type of birth and cohabitation with a partner. Newborn’s weight, previous pregnancy, UI during pregnancy, and sexual activity showed an association with UI after child birth. Only AI prior to pregnancy was associated with AI after childbirth. CONCLUSION Vaginal birth predisposes to the reduction of PFMS, and caesarean section had a protective effect to its reduction. The occurrence of UI during pregnancy is a predictor of UI after childbirth, and women with previous pregnancies and newborns with higher weights are more likely to have UI after childbirth.AI prior to pregnancy is the only risk factor for its occurrence after childbirth. Associations between PFMS and cohabitation with a partner, and between UI and sexual activity do not make possible to conclude that these variables are directly associated
Modelling the influence of age of steel fibre reinforced self-compacting concrete on its compressive behaviour
Steel fibre reinforced self-compacting
concrete (SFRSCC) can combine the benefits of
self-consolidating concrete technology with those
derived from adding steel fibres to quasi-brittle
cement based materials. In a recent applied research
project joining pre-casting industry, private and
public research institutions, a method was developed
to design cost-competitive SFRSCC of rheological
and mechanical properties required for the prefabrication
of SFRSCC fac¸ade panels. To assure safe
demoulding process of the panels, the influence of the
concrete age on the compression behaviour of the
SFRSCC should be known. For this purpose, series of
tests with specimens of 12 h to 28 days were tested in
order to analyze the age influence on the compressive
strength, strain at peak stress, Young’s modulus, and
compressive volumetric fracture energy. The experimental
program was divided in two groups of test
series, one with SFRSCC of a volumetric fibre
percentage of 0.38% and the other with 0.57%. To
apply the obtained data in the design and numerical
analysis framework, the influence of the age on
these SFRSCC properties was modelled. This work
describes the carried out experimental program, presents and analyzes the obtained results, and
provides the derived analytical expressions
Acute kidney disease and renal recovery : consensus report of the Acute Disease Quality Initiative (ADQI) 16 Workgroup
Consensus definitions have been reached for both acute kidney injury (AKI) and chronic kidney disease (CKD) and these definitions are now routinely used in research and clinical practice. The KDIGO guideline defines AKI as an abrupt decrease in kidney function occurring over 7 days or less, whereas CKD is defined by the persistence of kidney disease for a period of > 90 days. AKI and CKD are increasingly recognized as related entities and in some instances probably represent a continuum of the disease process. For patients in whom pathophysiologic processes are ongoing, the term acute kidney disease (AKD) has been proposed to define the course of disease after AKI; however, definitions of AKD and strategies for the management of patients with AKD are not currently available. In this consensus statement, the Acute Disease Quality Initiative (ADQI) proposes definitions, staging criteria for AKD, and strategies for the management of affected patients. We also make recommendations for areas of future research, which aim to improve understanding of the underlying processes and improve outcomes for patients with AKD
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