1,138 research outputs found

    Mutant monoclonal antibodies with alterations in biological functions

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    Somatic cell mutants with deletions in the immunoglobulin constant region were isolated from an IgG(2b) Ar-binding hybridoma. Rat anti-mouse immunoglobulins were used to identify the sites of the deletions. The mutant monoclonal antibodies differ from the parental molecule in their assembly states and are defective in various immunoglobulin activities, making them potentially more useful reagents

    3D-printed biomimetic artificial muscles using soft actuators that contract and elongate

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    Biomimetic machines able to integrate with natural and social environments will find ubiquitous applications, from biodiversity conservation to elderly daily care. Although artificial actuators have reached the contraction performances of muscles, the versatility and grace of the movements realized by the complex arrangements of muscles remain largely unmatched. Here, we present a class of pneumatic artificial muscles, named GeometRy-based Actuators that Contract and Elongate (GRACE). The GRACEs consist of a single-material pleated membrane and do not need any strain-limiting elements. They can contract and extend by design, as described by a mathematical model, and can be realized at different dimensional scales and with different materials and mechanical performances, enabling a wide range of lifelike movements. The GRACEs can be fabricated through low-cost additive manufacturing and even built directly within functional devices, such as a pneumatic artificial hand that is fully three-dimensionally printed in one step. This makes the prototyping and fabrication of pneumatic artificial muscle-based devices faster and more straightforward

    The CMS Event Builder

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    The data acquisition system of the CMS experiment at the Large Hadron Collider will employ an event builder which will combine data from about 500 data sources into full events at an aggregate throughput of 100 GByte/s. Several architectures and switch technologies have been evaluated for the DAQ Technical Design Report by measurements with test benches and by simulation. This paper describes studies of an EVB test-bench based on 64 PCs acting as data sources and data consumers and employing both Gigabit Ethernet and Myrinet technologies as the interconnect. In the case of Ethernet, protocols based on Layer-2 frames and on TCP/IP are evaluated. Results from ongoing studies, including measurements on throughput and scaling are presented. The architecture of the baseline CMS event builder will be outlined. The event builder is organised into two stages with intelligent buffers in between. The first stage contains 64 switches performing a first level of data concentration by building super-fragments from fragments of 8 data sources. The second stage combines the 64 super-fragments into full events. This architecture allows installation of the second stage of the event builder in steps, with the overall throughput scaling linearly with the number of switches in the second stage. Possible implementations of the components of the event builder are discussed and the expected performance of the full event builder is outlined.Comment: Conference CHEP0

    Operon mRNAs are organized into ORF-centric structures that predict translation efficiency

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    Bacterial mRNAs are organized into operons consisting of discrete open reading frames (ORFs) in a single polycistronic mRNA. Individual ORFs on the mRNA are differentially translated, with rates varying as much as 100-fold. The signals controlling differential translation are poorly understood. Our genome-wide mRNA secondary structure analysis indicated that operonic mRNAs are comprised of ORF-wide units of secondary structure that vary across ORF boundaries such that adjacent ORFs on the same mRNA molecule are structurally distinct. ORF translation rate is strongly correlated with its mRNA structure in vivo, and correlation persists, albeit in a reduced form, with its structure when translation is inhibited and with that of in vitro refolded mRNA. These data suggest that intrinsic ORF mRNA structure encodes a rough blueprint for translation efficiency. This structure is then amplified by translation, in a self-reinforcing loop, to provide the structure that ultimately specifies the translation of each ORF

    Extended Longevity of Reproductives Appears to be Common in Fukomys Mole-Rats (Rodentia, Bathyergidae)

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    African mole-rats (Bathyergidae, Rodentia) contain several social, cooperatively breeding species with low extrinsic mortality and unusually high longevity. All social bathyergids live in multigenerational families where reproduction is skewed towards a few breeding individuals. Most of their offspring remain as reproductively inactive “helpers” in their natal families, often for several years. This “reproductive subdivision” of mole-rat societies might be of interest for ageing research, as in at least one social bathyergid (Ansell's mole-rats Fukomys anselli), breeders have been shown to age significantly slower than non-breeders. These animals thus provide excellent conditions for studying the epigenetics of senescence by comparing divergent longevities within the same genotypes without the inescapable short-comings of inter-species comparisons. It has been claimed that many if not all social mole-rat species may have evolved similar ageing patterns, too. However, this remains unclear on account of the scarcity of reliable datasets on the subject. We therefore analyzed a 20-year breeding record of Giant mole-rats Fukomys mechowii, another social bathyergid species. We found that breeders indeed lived significantly longer than helpers (ca. 1.5–2.2fold depending on the sex), irrespective of social rank or other potentially confounding factors. Considering the phylogenetic positions of F. mechowii and F. anselli and unpublished data on a third Fukomys-species (F. damarensis) showing essentially the same pattern, it seems probable that the reversal of the classic trade-off between somatic maintenance and sexual reproduction is characteristic of the whole genus and hence of the vast majority of social mole-rats

    Large area and flexible micro-porous piezoelectric materials for soft robotic skin

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    The need for flexible, highly sensitive tactile sensors that can fit onto curved surfaces is driving the conformable sensor materials research in the field of human–machine interactions. Here we report a new type of compliant piezoelectric active composite, a micro-porous polyurethane-PZT material, capable of generating a voltage output upon touch. The composites are synthesized with the aim of maximizing the piezoelectric sensitivity of particulate composite sensor materials. The goal is to reduce the dielectric constant of the polymer matrix and improve flexibility of conventional bulk piezo-composites, consisting of ceramic particles in a dense polymeric matrix, by adding a third (gaseous) phase to the system in the form of uniformly sized pores. The presence of the gaseous component in the polymer matrix in the form of well-distributed spherical inclusions effectively decreases the polymer dielectric permittivity, which increases the piezoelectric voltage sensitivity (g33) of the composite sensors significantly. The unique combination of dielectrophoretic structuring of PZT particles and the addition of a gaseous phase to the polymer resin results in the highest performance of the particulate composite sensors reported in the literature so far. The newly developed micro-porous composites show g33 value of 165 mV m/N that is twice that of the structured PZT-bulk PU composites (80 mV m/N) and more than five times the g33 value of bulk PZT ceramics (24–28 mV m/N). The capability of the flexible freestanding sensors for application in touch sensing devices for soft robotics is demonstrated

    BENEFÍCIOS DA DRENAGEM LINFÁTICA MANUAL NA PANICULOPATIA EDEMATO FIBROESCLERÓTICA

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    Paniculopatia edemato fibroesclerótica (PEFE) popularmente conhecida como celulite, é uma afecção que ocasiona alterações inestéticas, caracterizadas por depressões e nódulos, principalmente em glúteos, coxas e abdômens da maioria das mulheres a partir da adolescência. Pouco ainda se conhece da sua fisiopatologia, sendo um assunto carente de estudos na área e, com tratamentos nem sempre toleráveis e efetivos. Estudos colocam os estrógenos como importantes no início, no desenvolvimento e cronificação da PEFE, pela influência na polimerização das glicosaminoglicanas, na microcirculação, nas proteínas fibrosas e no tecido adiposo da região ginóide, os quais são afetados em diferentes graus, podendo levar à reação fibrótica e à esclerose. A drenagem linfática manual consiste em um conjunto de manobras específicas, por meio de pressão suave, lenta e rítmica, que segue o trajeto do sistema linfático, e visa melhorar suas funções essenciais, prejudicadas nesta patologia. Desta maneira, este trabalho teve o objetivo de revisar na literatura a fisiopatologia da PEFE, e relacionar os benefícios da drenagem linfática manual nesta afecção, relacionando-a com a anatomofisiologia do sistema linfático

    Emotions and self-esteem as indicators of somatic complaints in children

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    The literature on somatic complaints in children without a clear physical medical cause often demonstrates connections with various psychological factors, such as negative emotions and problems handling them, poor self-image, and coping potential. We entered these elements into a structural model to elucidate the relationships among them and tested it on 330 children (mean age 10 years and 9 months). The results showed that mood balance contributed most to the prediction of self-reported somatic complaints. Moreover, mood (in combination with anxiety and depression problems) had an indirect impact on children's somatic complaints by influencing self-esteem. The influence and position of coping was less clear. The results are discussed in terms of the 'symptom perception theory'. Copyright © 2006 John Wiley & Sons, Ltd
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