On the formation of propylene oxide from propylene in space: gas-phase reactions

In the present article, we have investigated the possibility of forming propylene oxide (PO) from propylene (PE) by bi-molecular reactions. Propylene oxide is the first chiral molecule observed in the interstellar medium, and studying the thermodynamics and kinetics of formation can suggest possible synthetic routes. We have focused our attention on gas-phase reactions, and the presence of an environment is discussed in particular for the possibility of forming it by association reactions. In particular, we have considered radical and ion–molecule reactions. Results show that the main gas-phase route to PO formation is represented by ion–molecule reactions which turn out to be compatible with astrophysical conditions, notably: PE + O + and PE+HO2+. Their final product is not PO, but its ionized variant PO + that can be neutralized by electron capture. The only thermodynamically and kinetically allowed reaction which can directly lead to neutral PO is a collision of PE with a singlet-excited OH + but two competing reactions (leading to PE + and PO +) are thermodynamically favored and thus more plausible in space

Temporal lack of DNA methylation-mediated repression is a universal feature of vertebrate development

Resumen del póster presentado al IX Meeting of the Spanish Society for Developmental Biology celebrado en Granada del 12 al 14 de noviembre de 2012.-- et al.Peer Reviewe

Plant biodiversity of mountain grasslands as influenced by dairy farm management in the Eastern Alps

It has been widely demonstrated that farm management affects the plant species composition of grassland. The present study aimed to investigate the effect of farm management on plant species richness and composition in forty-nine small-scale farms breeding dairy cattle, located in the Eastern Italian Alps at two levels of precision: plot and farm levels. Data on housing system, quality scheme, farm productivity, income from milk yield and livestock density were collected through interviews with farmers. In each farm, botanical surveys were carried out in different plots representing the botanical composition of the farmland vegetation. Elevation, slope, type of use, number of hay cuts and type of fertilisation were also recorded. The botanical surveys of the plots on each farm were analysed to describe plant composition at the plot level, then merged to describe plant composition at the farm level. At both levels, grassland botanical composition was found to be affected by farm management. At the plot level, meadows cut 2 and 3 times per year did not exhibit any differences in plant richness, but they differed in plant species, botanical family and phytosociological class composition, with a general simplification of botanical composition. We found fewer phytosociological classes but not fewer plant species or botanical families in plots fertilised with slurry than in plots fertilised with manure or not fertilised, and a change in the botanical composition due to changes in the relative abundance of plant species. At the farm level, we observed a decrease in the number of plant species and phytosociological classes, and changes in plant composition, with increasing milk yield and livestock density. Changes in botanical composition were less evident at the farm level than at the plot level. However, protecting farms and their economic viability is a means of maintaining biodiversity at the plot level

Heat stress and feeding behaviour of dairy cows in late lactation

Heat stress is one of the most important problems that dairy cows have to face and the use of cooling systems is becoming more and more important. The first reaction that has the animal to cope with the environmental variations is to modify its behaviour. This study was aimed to investigate the effect of heat stress and a cooling system on the feeding behaviour of Italian Holstein Friesian dairy cows in late lactation. Two experiments were performed. In the first experiment, eight dairy cows were firstly kept 7 d under thermoneutral condition, and then under mild heat stress (temperature humidity index, THI, ranging between 72 and 78) for others 7 d. The second experiment consisted of 8 dairy cows used in a two-period cross-over design where the treatment was the use or not of a sprinkler system for cooling cows under mild heat stress. Cows were equipped with a noseband pressure sensor able to detect rumination and eating time, number of rumination and eating chews, number of rumination boluses and rumination intensity. Heat stress reduced rumination time, number of rumination chews and boluses (p <.05), and tended to reduce the number of eating chews (p <.10). Cooled cows increased rumination and eating time (p <.05), rumination intensity (p <.01), and the number of rumination and eating chews (p <.05). In conclusion, feeding behaviour was deeply influenced even by mild heat stress, which was effectively improved by the use of a sprinkler system.HIGHLIGHTS Mild heat stress reduced rumination time, number of rumination chews and boluses of dairy cows in late lactation Cooling cows with sprinklers was effective in alleviating heat stress in terms of feeding behaviour

Systematic Review and Critical Analysis of Cost Studies Associated with Parkinson's Disease

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease worldwide, affecting more than four million people. Typically, it affects individuals above 45, when they are still productive, compromising both aging and quality of life. Therefore, the cost of the disease must be identified, so that the use of resources can be rational and efficient. Additionally, in Brazil, there is a lack of research on the costs of neurodegenerative diseases, such as PD, a gap addressed in this study. This systematic review critically addresses the various methodologies used in original research around the world in the last decade on the subject, showing that costs are hardly comparable. Nonetheless, the economic and social impacts are implicit, and important information for public health agents is provided.Hosp Israelita Albert Einstein, Programa Posgrad, Sao Paulo, SP, BrazilUniv Fed Sao Paulo UNIFESP, Movement Disorders Dept Neurol, Sao Paulo, SP, BrazilUniv Fed Sao Paulo UNIFESP, Sao Paulo, SP, BrazilHosp Israelita Albert Einstein, Neurol Program, Sao Paulo, SP, BrazilMovement Disorders Department in Neurology, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, BrazilUniversidade Federal de São Paulo (UNIFESP), São Paulo, SP, BrazilWeb of Scienc

Sfrp1 deficiency makes retinal photoreceptors prone to degeneration

Millions of individuals worldwide suffer from impaired vision, a condition with multiple origins that often impinge upon the light sensing cells of the retina, the photoreceptors, affecting their integrity. The molecular components contributing to this integrity are however not yet fully understood. Here we have asked whether Secreted Frizzled Related Protein 1 (SFRP1) may be one of such factors. SFRP1 has a context-dependent function as modulator of Wnt signalling or of the proteolytic activity of A Disintegrin And Metalloproteases (ADAM) 10, a main regulator of neural cell-cell communication. We report that in Sfrp1^{-/-} mice, the outer limiting membrane (OLM) is discontinuous and the photoreceptors disorganized and more prone to light-induced damage. Sfrp1 loss significantly enhances the effect of the Rpe6^{Leu450Leu} genetic variant -present in the mouse genetic background- which confers sensitivity to light-induced stress. These alterations worsen with age, affect visual function and are associated to an increased proteolysis of Protocadherin 21 (PCDH21), localized at the photoreceptor outer segment, and N-cadherin, an OLM component. We thus propose that SFRP1 contributes to photoreceptor fitness with a mechanism that involves the maintenance of OLM integrity. These conclusions are discussed in view of the broader implication of SFRP1 in neurodegeneration and aging

Systematic review of outcome measures of walking training using electromechanical and robotic devices in patients with stroke

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Pαx6 Expression in Postmitotic Neurons Mediates the Growth of Axons in Response to SFRP1

During development, the mechanisms that specify neuronal subclasses are coupled to those that determine their axonal response to guidance cues. Pax6 is a homedomain transcription factor required for the specification of a variety of neural precursors. After cell cycle exit, Pax6 expression is often shut down in the precursor progeny and most postmitotic neurons no longer express detectable levels of the protein. There are however exceptions and high Pax6 protein levels are found, for example, in postmitotic retinal ganglion cells (RGCs), dopaminergic neurons of the olfactory bulb and the limbic system in the telencephalon. The function of Pax6 in these differentiating neurons remains mostly elusive. Here, we demonstrate that Pax6 mediates the response of growing axons to SFRP1, a secreted molecule expressed in several Pax6-positive forebrain territories. Forced expression of Pax6 in cultured postmitotic cortical neurons, which do not normally express Pax6, was sufficient to increment axonal length. Growth was blocked by the addition of anti-SFRP1 antibodies, whereas exogenously added SFRP1 increased axonal growth of Pax6-transfected neurons but not that of control or untransfected cortical neurons. In the reverse scenario, shRNA-mediated knock-down of Pax6 in mouse retinal explants specifically abolished RGCs axonal growth induced by SFRP1, but had no effect on RGCs differentiation and it did not modify the effect of Shh or Netrin on axon growth. Taken together these results demonstrate that expression of Pax6 is necessary and sufficient to render postmitotic neurons competent to respond to SFRP1. These results reveal a novel and unexpected function of Pax6 in postmitotic neurons and situate Pax6 and SFRP1 as pair regulators of axonal connectivity

Foxd1-dependent induction of a temporal retinal character is required for visual function

Appropriate patterning of the retina during embryonic development is assumed to underlie the establishment of spatially localised specialisations that mediate the perception of specific visual features. For example, in zebrafish, an area involved in high acuity vision (HAA) is thought to be present in the ventro-temporal retina. Here, we show that the interplay of the transcription factor Rx3 with Fibroblast Growth Factor and Hedgehog signals initiates and restricts foxd1 expression to the prospective temporal retina, initiating naso-temporal regionalisation of the retina. Abrogation of Foxd1 results in the loss of temporal and expansion of nasal retinal character, and consequent absence of the HAA. These structural defects correlate with severe visual defects, as assessed in optokinetic and optomotor response assays. In contrast, optokinetic responses are unaffected in the opposite condition, in which nasal retinal character is lost at the expense of expanded temporal character. Our study indicates that the establishment of temporal retinal character during early retinal development is required for the specification of the HAA, and suggests a prominent role of the temporal retina in controlling specific visual functions