417 research outputs found
Supraspinal reorganization after pediatric-onset spinal cord injury.
Pediatric spinal cord injury (SCI) disrupts the efferent and afferent flow of the developing brain, leading to devastating functional impairments below the injury site, yet our understanding of its impact on the brain remains limited. This study examines supraspinal reorganization in children with SCI using electrophysiology and neuroimaging techniques to understand the relationship between residual spinal transmission and supraspinal reorganization. Chapter 2 discusses the development of a child-centric approach using ‘learn, play, and practice’ to foster a trusting relationship with each child and increase compliance with experimental protocols. Chapter 3 evaluates the residual neural transmission of three spinal pathways in children with SCI, revealing that supraspinal inputs onto spinal motor circuitry persist despite a clinical diagnosis of complete SCI. This finding supports the concept of discomplete injuries and suggests that clinical assessments may not fully capture the extent of residual sensorimotor function in this population. The neural conduction of the corticospinal tract (CST), the primary mediator of volitional motor function, was assessed via functional neurophysiological assessment (FNPA). Reticulospinal tract (RST) activity, crucial for movement coordination, was evaluated using acoustic startle response (ASR). Finally, the functional transmission of the dorsal column-medial lemniscus (DCML) pathway, which conveys touch information from the periphery to the brain, was evaluated by analyzing somatosensory evoked potentials (SSEP). In Chapter 4, the impact of SCI on the pediatric brain was investigated using neuroimaging techniques. Analysis of 8 children with SCI and 18 age- and gender-matched typically developing controls showed reduced gray matter morphometry and functional connectivity in cortical and subcortical sensorimotor structures and lower CST microstructural integrity in the brains of children with SCI. Additional analysis reveals that higher cortical and subcortical neuroimaging measures were associated with a higher probability of volitional muscle activation, and higher RST activity levels were correlated with better measurements of subcortical morphometry and functional connectivity. These findings provide valuable insights into the effects of pediatric SCI on the brain and their underlying relationships to motor pathways activity, suggesting the potential of supraspinal neuroimaging to serve as biomarkers to assess recovery and track the efficacy of interventions targeting spinal translesional connectivity
Rubisco function, evolution, and engineering
Carbon fixation is the process by which CO2 is converted from a gas into
biomass. The Calvin Benson Bassham (CBB) cycle is the dominant carbon fixation
pathway on earth, driving >99.5% of the ~120 billion tons of carbon that are
"fixed" as sugar, by plants, algae and cyanobacteria. The carboxylase enzyme in
the CBB, ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco), fixes one
CO2 molecule per turn of the cycle. Despite being critical to the assimilation
of carbon, rubisco's kinetic rate is not very fast and it is a bottleneck in
flux through the pathway. This presents a paradox - why hasn't rubisco evolved
to be a better catalyst? Many hypothesize that the catalytic mechanism of
rubisco is subject to one or more trade-offs, and that rubisco variants have
been optimized for their native physiological environment. Here we review the
evolution and biochemistry of rubisco through the lens of structure and
mechanism in order to understand what trade-offs limit its improvement. We also
review the many attempts to improve rubisco itself and, thereby, promote plant
growth
Characteristics of homogeneous multi-core fibers for SDM transmission
We describe optical data transmission systems using homogeneous, single-mode, multi-core fibers (MCFs). We first briefly discuss space-division multiplexing (SDM) fibers, observing that no individual SDM fiber offers overwhelming advantages over bundles of single-mode fiber (SMF) across all transmission regimes. We note that for early adoption of SDM fibers, uncoupled or weakly coupled fibers which are compatible with existing SDM infrastructure have a practical advantage. Yet, to be more attractive than parallel SMF, it is also necessary to demonstrate benefits beyond improved spatial spectral efficiency. It is hoped that the lower spread of propagation delays (skew) between spatial channels in some fibers can be exploited for improved performance and greater efficiency from hardware sharing and joint processing. However, whether these benefits can be practically harnessed and outweigh impairments or effort to mitigate cross talk between spatial channels is not yet clear. Hence, focusing on homogeneous MCFs, we first describe measurements and simulations on the impact of inter-core cross talk in such fibers before reporting experimental investigation into the spatial channel skew variation with a series of the experimental results including a comparison with SMF in varying environmental conditions. Finally, we present some system and transmission experiments using parallel recirculating loops that enable demonstration of both multi-dimensional modulation and joint digital processing techniques across three MCF cores. Both techniques lead to increased transmission reach but highlight the need for further experimental analysis to properly characterize the potential benefits of correlated propagation delays in such fibers
Quince (Cydonia oblonga) in vitro plant root formation through an automated temporary inmersion system, and its acclimation
Artículo científicoQuince (Cydonia oblonga) is a non-traditional fruit tree found in Costa Rica that has
therapeutic and nutritional properties; however its slow growth and root formation prevents the production
of a homogeneous population when using conventional farming techniques. Hence, the aim of this research
project was to generate uniform plant material in a reduced time span using a temporary immersion bioreactor
system (RITAS ®). A semisolid rooting MS culture medium supplemented with 0.1 mg L-1 NAA; 0.3 mg L-1
IBA and 3% sucrose (pH 6.5), developed in the Centro de Investigación en Biotecnología (CIB), Instituto
Tecnológico de Costa Rica (ITCR), in Cartago, was used as a reference medium. Four different variations
in the sucrose concentration (1%, 2%, 3%, and 4%) were performed in liquid medium. Each trial was
evaluated with in vitro plants which had been previously exposed to the culture medium of the corresponding
treatments, in a stationary mode and for a 15 day long period, and with in vitro plants without any previous
treatment (a total of eight treatments). The comparison of the root formation percentages evidenced the clear
effect of sucrose concentration used, with the best results obtained when using the 2% sucrose trial with no
pre-treatment (73.3%). The in vitro plants were acclimated in cylinders made out of peat, have previously
been disinfected with fungicide, and placed in a humidity chamber at a 20.5°C average temperature and a
75,5% relative humidity for the establishment of weekly fertilizing cycles. The acclimation process generated
an 80% survival rate, since several seedlings experienced stem strangulation caused by a fungal attack.
The conidiophores identified through optical and scanning electron microscopy evidenced the presence of
Cladosporium spp., which was controlled with carbendazim and iprodione fungicides
Agglomerations and firm performance: who benefits and how much?
[EN] Agglomerations and firm performance: who benefits and how much? Regional Studies. Agglomeration can generate gains. If it does, how does it work and how are those gains distributed across agglomerated firms? The paper examines the effect
of localization externalities on innovation. Localization externalities are measured as industry specialization or a firm s colocation in a relatively high own-industry employment region. By analyzing a large dataset of 6697 firms integrated with
another regional agglomeration-related dataset, results show that (1) co-location in an agglomeration has a positive influence on a firm s innovative performance; and (2) firms benefit heterogeneously from agglomerations, with benefits being distributed asymmetrically. Agglomeration gains exist but not all firms benefit equally.Financial support was provided by the Spanish Ministry of Economics, Industry and Competitiveness [research grant ECO:2015-63645-R] (Mineco/Feder), Open Innovation in Clusters.Hervás Oliver, JL.; Sempere-Ripoll, F.; Rojas Alvarado, RJ.; Estelles Miguel, S. (2018). Agglomerations and firm performance: who benefits and how much?. Regional Studies. 52(3):338-349. https://doi.org/10.1080/00343404.2017.1297895S33834952
Registro continental de digitonthophagus gazella (coleoptera: scarabaeidae) en colombia
Con el fin de contribuir en la remocióndel excremento depositado por el ganadoel escarabajo coprófago Digitonthophagusgazella (Fabricius, 1787) fue liberado demanera deliberada en Texas (EE.UU.)en 1972 (Blume and amp; Aga 1978, Fincher etal. 1983) y posteriormente en California,Louisiana, Georgia y Florida
Plan de negocio para determinar la viabilidad de constituir una empresa de dise?o y fabricaci?n de m?quinas trituradoras de Cizalla
Nuestra tesis, enfocada en la fabricaci?n de maquinaria industrial, aspira a ser una buena opci?n manufacturera que brinde: valor agregado a la materia prima, genere empleo y sobretodo que beneficie a la sociedad y al medio ambiente. Para ello, hemos identificado un problema de com?n denominador a nivel mundial, la excesiva generaci?n de residuos s?lidos, en contraparte hemos revisado soluciones para corregir y/o aliviar esta situaci?n, eligiendo la m?quina trituradora de cizalla como la opci?n m?s amigable y confiable para reducir el tama?o de los residuos s?lidos, cualquiera sea su origen. Para el Estudio de Mercado, ten?amos que estudiar el proceso de gesti?n de residuos s?lidos en Lima Metropolitana; y elegir certeramente nuestra posible cartera de clientes, en algunos casos ideando estrategias para crear la demanda la cual era nula. Estimada la demanda, ideamos el Plan de Marketing que haga atractivo y sostenible nuestro Plan de Negocio y en funci?n a ello creamos nuestro Plan de Operaciones, considerando proveedores, procesos, costos y legislaci?n vigente. Finalmente nuestro Plan Financiero reflej? que nuestra idea de negocio s? era rentable y atractiva. Esperamos que esta Tesis sea de gu?a para futuras ideas de negocios en nuestra incipiente industria manufacturera peruana
Minimal cobalt metabolism in the marine cyanobacterium Prochlorococcus.
Despite very low concentrations of cobalt in marine waters, cyanobacteria in the genus Prochlorococcus retain the genetic machinery for the synthesis and use of cobalt-bearing cofactors (cobalamins) in their genomes. We explore cobalt metabolism in a Prochlorococcus isolate from the equatorial Pacific Ocean (strain MIT9215) through a series of growth experiments under iron- and cobalt-limiting conditions. Metal uptake rates, quantitative proteomic measurements of cobalamin-dependent enzymes, and theoretical calculations all indicate that Prochlorococcus MIT9215 can sustain growth with less than 50 cobalt atoms per cell, ∼100-fold lower than minimum iron requirements for these cells (∼5,100 atoms per cell). Quantitative descriptions of Prochlorococcus cobalt limitation are used to interpret the cobalt distribution in the equatorial Pacific Ocean, where surface concentrations are among the lowest measured globally but Prochlorococcus biomass is high. A low minimum cobalt quota ensures that other nutrients, notably iron, will be exhausted before cobalt can be fully depleted, helping to explain the persistence of cobalt-dependent metabolism in marine cyanobacteria
Human papillomavirus infections in women seeking cervical Papanicolaou cytology of Durango, Mexico: prevalence and genotypes
BACKGROUND: HPV infection in women from developing countries is an important public health problem. Therefore, we sought to determine the prevalences of HPV infection and HPV genotypes in a female population of Durango City, Mexico. Also to determine whether any socio-demographic characteristic from the women associated with HPV infection exists. METHODS: Four hundred and ninety eight women seeking cervical Papanicolaou examination in three public Health Centers were examined for HPV infection. All women were tested for HPV DNA PCR by using HPV universal primers. In addition, all positive HPV DNA PCR samples were further analyzed for genotyping of HPV genotype 16, 18 and 33. Socio-demographic characteristics from each participant were also obtained. RESULTS: Twenty-four out of four hundred and ninety-eight (4.8%) women were found infected by HPV. HPV genotype 16 was found in 18 out of the 24 (75%) infected women. Two of them were also coinfected by HPV genotype 18 (8.3%). In the rest 6 PCR positive women, genotyping for HPV genotypes 16, 18 and 33 were negative. CONCLUSION: The prevalence of HPV in women of Durango City is low; however, most infected women have high risk HPV genotype. The women who were studied showed low frequency of risk factors for HPV infection and this may explain the low prevalence of HPV infection. The high frequency of high risk HPV genotypes observed might explain the high rate of mortality for cervical cancer in our region
Risks of dengue secondary infective biting associated with aedes aegypti in home environments in Monterrey, Mexico
Abstract. Secondary dengue virus infections are a major risk for developing dengue hemorrhagic fever. Recent exposure to infectious bites of Aedes aegypti (L.) females in previously diagnosed dengue cases fulfills the epidemiological model of dengue hemorrhagic fever. A study was comprised of 357 (89.2%) dengue and 43 (10.8%) dengue hemorrhagic fever cases confirmed by laboratory tests and clinical manifestations. An entomological survey was done in homes and backyards. Concurrently, a questionnaire was used to assess the impact of healthpromotion campaigns through knowledge of the vector and its epidemiological role. Seventy-six (28.4%) of the 268 (67.0%) total wet or dry oviposition sites were
positive for the presence of larvae or pupae, while adult Ae. aegypti were found in 32 (8.0%). One hundred thirty-two (33%) householders who formerly had dengue fever or dengue hemorrhagic fever had knowledge of either larval or adult dengue vector stages. According to gender distribution, 145 (36.2%) and 14 (3.5%) of the males confirmed with cases of dengue and dengue hemorrhagic fever lived in houses with 17.9 and 2% of the Ae. aegypti larval and pupal habitats. Houses with females who had dengue and dengue hemorrhagic fever were 212 (53%) and 29
(7.3%), with containers with immature Ae. aegypti in 19.4 and 7%, respectively. Lack of sustainability of government-targeted health education campaigns is the
major problem for involving communities in prevention and control of dengu
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