Composite Wood–Concrete Structural Floor System with Horizontal Connectors

The concept of horizontal shear connection utilization on wood–concrete beams intends to be an alternative connection detail for composite wood–concrete decks. The volume of sawn-wood is over three times more expensive than concrete, in Brazil. In order to be competitive in the Brazilian market we need a composite deck with the least amount of wood and a simple and inexpensive connection detail. This research project uses medium to high density tropical hardwoods managed from the Brazilian Amazon region and construction steel rods. The beams studied are composed of a bottom layer of staggered wood boards and a top layer of concrete. The wood members are laterally nailed together to form a wide beam, and horizontal rebar connectors are installed before the concrete layer is applied on top. Two sets of wood–concrete layered beams with horizontal rebar connectors (6 and 8) were tested in third-point loading flexural bending. The initial results reveal medium composite efficiency for the beams tested. An improvement on the previously conceived connection detail (set with six connectors) for the composite wood–concrete structural floor system was achieved by the set with eight connectors. The new layout of the horizontal rebar connectors added higher composite efficiency for the beams tested. Further analysis with advanced rigorous numerical Finite Element Modeling is suggested to optimize the connection parameters. Composite wood–concrete decks can attend a large demand for pedestrian bridges, as well as residential and commercial slabs in the Brazilian Amazon. © 2014, The Author(s)

Postsynaptic dysfunction is associated with spatial and object recognition memory loss in a natural model of Alzheimer's disease

Alzheimer’s disease (AD) is an age-related neurodegenerative disorder associated with progressive memory loss, severe dementia, and hallmark neuropathological markers, such as deposition of amyloid-β (Aβ) peptides in senile plaques and accumulation of hyperphosphorylated tau proteins in neurofibrillary tangles. Recent evidence obtained from transgenic mouse models suggests that soluble, nonfibrillar Aβ oligomers may induce synaptic failure early in AD. Despite their undoubted value, these transgenic models rely on genetic manipulations that represent the inherited and familial, but not the most abundant, sporadic form of AD. A nontransgenic animal model that still develops hallmarks of AD would be an important step toward understanding how sporadic AD is initiated. Here we show that starting between 12 and 36 mo of age, the rodent Octodon degus naturally develops neuropathological signs of AD, such as accumulation of Aβ oligomers and phosphorylated tau proteins. Moreover, age-related changes in Aβ oligomers and tau phosphorylation levels are correlated with decreases in spatial and object recognition memory, postsynaptic function, and synaptic plasticity. These findings validate O. degus as a suitable natural model for studying how sporadic AD may be initiated

Neurodevelopmental Disruption of Cortico-Striatal Function Caused by Degeneration of Habenula Neurons

The habenula plays an important role on cognitive and affective functions by regulating monoamines transmission such as the dopamine and serotonin, such that its dysfunction is thought to underlie a number of psychiatric conditions. Given that the monoamine systems are highly vulnerable to neurodevelopmental insults, damages in the habenula during early neurodevelopment may cause devastating effects on the wide-spread brain areas targeted by monoamine innervations.Using a battery of behavioral, anatomical, and biochemical assays, we examined the impacts of neonatal damage in the habenula on neurodevelopmental sequelae of the prefrontal cortex (PFC) and nucleus accumbens (NAcc) and associated behavioral deficits in rodents. Neonatal lesion of the medial and lateral habenula by ibotenic acid produced an assortment of behavioral manifestations consisting of hyper-locomotion, impulsivity, and attention deficit, with hyper-locomotion and impulsivity being observed only in the juvenile period, whereas attention deficit was sustained up until adulthood. Moreover, these behavioral alterations were also improved by amphetamine. Our study further revealed that impulsivity and attention deficit were associated with disruption of PFC volume and dopamine (DA) receptor expression, respectively. In contrast, hyper-locomotion was associated with decreased DA transporter expression in the NAcc. We also found that neonatal administration of nicotine into the habenula of neonatal brains produced selective lesion of the medial habenula. Behavioral deficits with neonatal nicotine administration were similar to those caused by ibotenic acid lesion of both medial and lateral habenula during the juvenile period, whereas they were different in adulthood.Because of similarity between behavioral and brain alterations caused by neonatal insults in the habenula and the symptoms and suggested neuropathology in attention deficit/hyperactivity disorder (ADHD), these results suggest that neurodevelopmental deficits in the habenula and the consequent cortico-striatal dysfunctions may be involved in the pathogenesis and pathophysiology of ADHD

Fluid challenges in intensive care: the FENICE study A global inception cohort study

Fluid challenges (FCs) are one of the most commonly used therapies in critically ill patients and represent the cornerstone of hemodynamic management in intensive care units. There are clear benefits and harms from fluid therapy. Limited data on the indication, type, amount and rate of an FC in critically ill patients exist in the literature. The primary aim was to evaluate how physicians conduct FCs in terms of type, volume, and rate of given fluid; the secondary aim was to evaluate variables used to trigger an FC and to compare the proportion of patients receiving further fluid administration based on the response to the FC.This was an observational study conducted in ICUs around the world. Each participating unit entered a maximum of 20 patients with one FC.2213 patients were enrolled and analyzed in the study. The median [interquartile range] amount of fluid given during an FC was 500 ml (500-1000). The median time was 24 min (40-60 min), and the median rate of FC was 1000 [500-1333] ml/h. The main indication for FC was hypotension in 1211 (59 %, CI 57-61 %). In 43 % (CI 41-45 %) of the cases no hemodynamic variable was used. Static markers of preload were used in 785 of 2213 cases (36 %, CI 34-37 %). Dynamic indices of preload responsiveness were used in 483 of 2213 cases (22 %, CI 20-24 %). No safety variable for the FC was used in 72 % (CI 70-74 %) of the cases. There was no statistically significant difference in the proportion of patients who received further fluids after the FC between those with a positive, with an uncertain or with a negatively judged response.The current practice and evaluation of FC in critically ill patients are highly variable. Prediction of fluid responsiveness is not used routinely, safety limits are rarely used, and information from previous failed FCs is not always taken into account

Low catalytic activity is insufficient to induce disease pathology in triosephosphate isomerase (TPI) deficiency

Triosephosphate isomerase (TPI) deficiency is a fatal genetic disorder characterized by hemolytic anemia and neurological dysfunction. Although the enzyme defect in TPI was discovered in the 1960s, the exact etiology of the disease is still debated. Some aspects indicate the disease could be caused by insufficient enzyme activity, whereas other observations indicate it could be a protein misfolding disease with tissue-specific differences in TPI activity. We generated a mouse model in which exchange of a conserved catalytic amino acid residue (isoleucine to valine, Ile170Val) reduces TPI specific activity without affecting the stability of the protein dimer. TPIIle170Val/Ile170Val mice exhibit an approximately 85% reduction in TPI activity consistently across all examined tissues, which is a stronger average, but more consistent, activity decline than observed in patients or symptomatic mouse models that carry structural defect mutant alleles. While monitoring protein expression levels revealed no evidence for protein instability, metabolite quantification indicated that glycolysis is affected by the active site mutation. TPIIle170Val/Ile170Val mice develop normally and show none of the disease symptoms associated with TPI deficiency. Therefore, without the stability defect that affects TPI activity in a tissue-specific manner, a strong decline in TPI catalytic activity is not sufficient to explain the pathological onset of TPI deficiency

Zmiany zawartosci chlorofilu a i b oraz amoniaku u wybranych gatunkow roslin rabatowych pod wplywem stresu suszy

Badania nad reakcją roślin rabatowych na stres suszy przeprowadzono w sezonie wegetacyjnym 2004 roku w szklarniach Katedry Roślin Ozdobnych SGGW. Materiałem doświadczalnym były dwa gatunki roślin: niecierpek Walleriana (Impatiens walleriana ‘Deep Rose’) i pelargonia rabatowa (Pelargonium X hortorum 'Deep Red’). Określono wpływ 3 poziomów SWC, 3 stężeń chlorku wapnia (0%, 0,1% i 1%) oraz 3 okresów suszy na zawartość chlorofilu i amoniaku w liściach badanych roślin. Pod wpływem suszy zwiększyła się zawartość amoniaku u niecierpka i pelargonii oraz zmniejszyła zawartość chlorofilu w liściach niecierpka. Niski poziom SWC nie miał wpływu na zawartość chlorofilu u pelargonii. Dolistne zastosowanie 1% roztworu CaCl₂ wpłynęło korzystnie na jakość roślin w warunkach stresu suszy, co wyraziło się zmniejszeniem strat chlorofilu i ograniczeniem wzrostu poziomu amoniaku.The experiment on the effect of drought on bedding plants was carried out in the greenhouses of the Department of Ornamental Plants during the vegetative season of 2004. The experimental material was two plant species: Impatiens walleriana ‘Deep Rose' and Pelargonium x hortorum ‘Deep Red’. The effect of three SWC levels, three calcium chloride concentrations (0%, 0.1% and 1%) and three drought cycles on chlorophyll and ammonium contents was examined. The ammonium content increased in both species under drought stress. Chlorophyll content decreased in Impatiens walleriana while there was no effect of low SWC on the pigment content in Pelargonium X hortorum. Spraying plants with of 1% calcium chloride reduced chlorophyll loss and ammonium accumulation

Molluscs of the middle and lower Odra: the role of the river in the expansion of alien species in Poland

The malacofauna of the middle and lower Odra (Oder River), a large river degraded by human ac- tivities, is still rich and diversified. Fifty five mollusc species were recorded from 31 studied localities: 32 Gastropoda and 23 Bivalvia. The highest number of species (47) inhabited the areas between groynes, whereas the fewest species (20) were found in the river current outside groynes. As many as 14.5% of the re- corded species were alien to the Polish fauna: Lithoglyphus naticoides, Potamopyrgus antipodarum, Physella acuta, Ferrissia fragilis, Menetus dilatatus, Corbicula fluminalis, C. fluminea, and Dreissena polymorpha. The presence of so many alien species shows that the Odra, together with the system of canals (which through the Spree and the Havel connect it to the drainage basin of the Elbe), is a major route along which alien molluscs migrate to Poland