66 research outputs found
Infection of pearl oyster, Pinctada margaritifera with Cliona sp. and subsequent destruction of oyster shell
One of the major problems of pearl oyster cage culture in the Persian Gulf is boring and fouling organisms attacking oyster under culture. The infected oyster lose their commercial longevity, heathy resulting in a decrease in pearl production capability. P. margaritifera is one of the rarest species of pearl oysters in the Persian Gulf. As such much research are now being under taken to study the parasites and their relationship with host organism in an effort to protect its stocks. Cliona sp. has been found to be the most common parasite, causing much destruction to the oysters. In this article the extent of oysters infested with this parasite and subsequent destruction of oyster shells is described
Substrate Stiffness Controls Osteoblastic and Chondrocytic Differentiation of Mesenchymal Stem Cells without Exogenous Stimuli
Stem cell fate has been linked to the mechanical properties of their underlying substrate, affecting mechanoreceptors and ultimately leading to downstream biological response. Studies have used polymers to mimic the stiffness of extracellular matrix as well as of individual tissues and shown mesenchymal stem cells (MSCs) could be directed along specific lineages. In this study, we examined the role of stiffness in MSC differentiation to two closely related cell phenotypes: osteoblast and chondrocyte. We prepared four methyl acrylate/methyl methacrylate (MA/MMA) polymer surfaces with elastic moduli ranging from 0.1 MPa to 310 MPa by altering monomer concentration. MSCs were cultured in media without exogenous growth factors and their biological responses were compared to committed chondrocytes and osteoblasts. Both chondrogenic and osteogenic markers were elevated when MSCs were grown on substrates with stiffnesschondrocytes, MSCs on lower stiffness substrates showed elevated expression of ACAN, SOX9, and COL2 and proteoglycan content; COMP was elevated in MSCs but reduced in chondrocytes. Substrate stiffness altered levels of RUNX2 mRNA, alkaline phosphatase specific activity, osteocalcin, and osteoprotegerin in osteoblasts, decreasing levels on the least stiff substrate. Expression of integrin subunits α1, α2, α5, αv, β1, and β3 changed in a stiffness- and cell type-dependent manner. Silencing of integrin subunit beta 1 (ITGB1) in MSCs abolished both osteoblastic and chondrogenic differentiation in response to substrate stiffness. Our results suggest that substrate stiffness is an important mediator of osteoblastic and chondrogenic differentiation, and integrin β1 plays a pivotal role in this process
Imaging bacteria with radiolabelled quinolones, cephalosporins and siderophores for imaging infection: a systematic review
Estudo biológico e comportamental de lagartas de Spodoptera frugiperda visando à produção de Baculovírus spodoptera
A utilização de bioinseticida a base de Spodoptera frugiperda
multiple nucleopolyhedrovirus (SfMNPV) possui potencial para o controle de
Spodoptera frugiperda (Lepidoptera: Noctuidae), porém sua obtenção em larga
escala depende da maximização da produção in vivo. Assim, alguns fatores
biológicos e comportamentais devem ser estudados para aperfeiçoar a
produção de SfMNPV com intuito de disponibilizar um bioinseticida eficiente,
economicamente viável e que possa ser usado no manejo de S. frugiperda nos
mais diversos sistemas agrícolas. Entre os fatores relacionados ao hospedeiro,
a temperatura e a idade para inoculação do vírus são de extrema importância,
pois interferem diretamente no ciclo de vida e na replicação viral. O
comportamento também deve ser avaliado, para evitar condições de criação do
hospedeiro que favoreçam o canibalismo e causa prejuízo na multiplicação in
vivo do SfMNPV. Assim, objetivou-se determinar a melhor condição térmica
para criar as lagartas e a idade ideal, para inocular e multiplicar o vírus no
hospedeiro, bem como, verificar a ocorrência do comportamento canibal em
lagartas de S. frugiperda. Os experimentos foram conduzidos no Laboratório de
Controle Microbiano de Insetos do Núcleo de Desenvolvimento Científico e
Tecnológico em Manejo Fitossanitário de Pragas e Doenças (NUDEMAFI),
localizado no Centro de Ciências Agrárias da UFES, em Alegre, Espírito Santo,
Brasil. A pesquisa foi desenvolvida em duas etapas, a primeira para determinar
a condição térmica e a idade ideais para criar e inocular, respectivamente, o
hospedeiro com o vírus, para multiplicação in vivo de SfMNPV. A segunda
etapa foi para avaliar o comportamento canibal de lagartas da espécie S.
frugiperda criadas a 22, 25 e 31°C, inoculadas com SfMNPV quando com
idades de 10, 8 e 4 dias, respectivamente, e mantidas em diferentes
densidades populacionais (5, 10, 25 e 50 lagartas por recipiente). A
mortalidade diminuiu com o aumento da temperatura e da idade do hospedeiro
nas temperaturas de 25, 28 e 31 °C. O aumento na taxa de canibalismo foi
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diretamente proporcional à densidade populacional quando as lagartas foram
criadas a 22 °C, inoculadas aos 10 dias de idade e 25 ºC, inoculadas aos 8
dias e atingiram 63,5 e 62,5%, respectivamente na densidade populacional de
50 lagartas. Mas, quando as lagartas foram criadas a 31ºC e inoculadas com
idade de 4 dias, a densidade populacional não afetou o comportamento
canibal, taxa média de 24%, inferior aos outros tratamentos com 50 lagartas
por recipiente. Demonstrando que é viável para a multiplicação viral, criar
lagartas a 31 °C e aos 4 dias de idade inocular o vírus, podendo a partir de
então colocar até 50 lagartas por recipiente, o que reduz a mão-de-obra
necessária para individualizar as lagartas e otimiza o espaço físico em uma
biofábrica. Portanto, se para otimizar o processo produção viral e o serviço em
uma biofábrica, é preciso maximizar a produção viral, reduzir o tempo de
multiplicação do vírus e o canibalismo entre as lagartas, com ausência de
contaminação da criação, a temperatura e idade ideais para criação massal de
S. frugiperda e inoculação do vírus nas lagartas, respectivamente, visando
produção de baculovírus em larga escala são de 31 ºC e 4 dias
Infestation of pearl oysters by boring and fouling organisms in the northern Persian Gulf
168-169Infestation of the pearl oysters Pinctada margaritifera and Pinctada radiata by boring and fouling organisms at pearl culture farms, as well as in the wild, was studied on the northern coast of the Persian Gulf. Barnacles, spat of edible oysters and tubiculous polychaetes were major fouling organisms in the pearl culture farms. In natural beds, however, fouling sponges, algae and ascidians were considered to be the main fouling organisms. The sponge Cliona and mussel Lithophaga were the most destructive boring organisms encountered causing considerable damage to the shells
Reconstruction of Interfering Waves from Three Dimensional Analysis of Their Interference Pattern
Optical interferometry is being used as an efficient tool to analyse smooth surfaces for more than a century. Although, due to introduction of novel computer assisted analyzing techniques and array detectors, like CCD, the speed and the precision of processing have been increased tremendously, but the main equation involved is not changed. The main equation is the intensity distribution in the interference pattern of a plane reference wave and the required wave. In the paper it is shown that by analysis of the interference pattern of two unknown waves in three dimension (which is possible for coherent waves) it is possible to reconstruct each wave separately. This approach has several useful applications, namely, on can do without reference plane wave in the interferometric surface analysis and, it is possible to reconstruct an unknown wave by making it to interfere with itself. This is very useful in determining the profile of laser beams and erasing the effect of atmospheric disturbances on observing astronomical objects
Finite Element Analysis of Permanent Magnet Synchronous Motors Subjected to Symmetrical Voltage Sags
This paper studies the effects of symmetrical voltage sags on the operational characteristics of a Permanent Magnet Synchronous Motor (PMSM) by Finite Element Method (FEM). Voltage sags may cause high torque pulsations which can damage the shaft or equipment connected to the motor. By recognizing the critical voltage sags, sags that produce hazardous torque variations could be prevented. Simulations results will be provided and the critical voltage sags are recognized. A simple theoretical analysis will also be presented to obtain a qualitative understanding of the phenomena occurring in PMSM during symmetrical voltage sag
Evaluation of the Rate of Data Transfer, Learning, and Ease of Access to Data via Data Visualization in Virtual Medical Courses from the Viewpoint of Teachers and Students in Shahid Beheshti University of Medical Sciences
Variation in clearance and ingestion rates by larvae of the black-lip pearl oyster (Pinctada margaritifera, L.) feeding on various microalgae
Clearance rate (CR) and ingestion rate (IR) of different sizes (89, 125 and 188 μm shell length) of Pinctada margaritifera larvae were determined when feeding on various microalgae. The microalgae tested were the diatoms, Chaetoceros muelleri and C. simplex, and flagellates, Tahitian Isochrysis aff. galbana, Pavlova lutheri and P. salina at 5 or 10 cells μL–1. Both CR and IR of microalgae tested in this study increased with increasing larval size; but at all larval sizes, diatoms resulted in lower CR and IR. Of the microalgae tested, P. margaritifera larvae showed greatest CR and IR with the two Pavlova spp. Maximum CR for P. salina was 10.5, 21.2 and 29.7 μL h–1 for larvae with shell lengths of 89, 125 and 188 μm, respectively. The highest IR values for P. margaritifera larvae with shell lengths of 89, 125 and 188 μm were 8.7, 81.0 and 165.7 cells·larva–1 h–1, respectively. CR and IR of P. salina were approximately five times higher than those recorded for C. muelleri and C. simplex
Learning from the systematic approach to aquaculture zoning in South Australia: a case study of aquaculture (Zones - Lower Eyre Peninsula) Policy 2013
Abstract not availablePeter Lauer, Lambertus López, Emmanuelle Sloan, Sean Sloan, Mehdi Doroud
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