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Polymer Crosslinking: a new Strategy to Enhance Mechanical Properties and Structural Stability of Bioactive Glasses

The organic-inorganic hybrids fabricated by the sol-gel method are intrinsically bioactive materials with extensive applications in bone tissue engineering. The brittleness and limited water uptake capacity of these monoliths, however, restrict their applications for engineering the soft tissues and their interfaces with bone. To address these challenges, we developed a unique method in which polymer crosslinking was used to cease the over-condensation of a bioactive glass component and eradicate the formation of brittle structure. In this study, an organosilane-functionalized gelatin methacrylate was covalently bonded to a bioactive glass during the sol-gel process, and the condensation of silica networks was controlled by polymer-crosslinking. The physicochemical properties and mechanical strength of these hybrid hydrogels were then tuned by the incorporation of secondary crosslinking agents such as poly(ethylene glycol diacrylate). The resulting elastic hydrogels displayed tuneable compressive modulus in the range of 42 kPa to 530 kPa. The swelling behaviours of these hybrids and their structural integrities were also favourable for tissue engineering applications. Moreover, these hybrid hydrogels kept their structures for more than 28 days in simulated body fluid. The bioactivity of the constructs due to the presence of silica networks were confirmed by detecting nearly 2-fold increase in the alkaline phosphatase activity of the cultured bone progenitor cells on these hybrid hydrogels within 28 days of in vitro culture. Within the same period, in vivo studies on mice subcutaneous model showed that the hybrid hydrogels were highly biocompatible and well-tolerated. In summary, the bioactivity of the constructs, their tuneable physicochemical properties, the outstanding biocompatibility, and biodegradability of the hybrid hydrogels showed the high potential of the developed technique for fabrication of constructs for a variety of soft and hard tissue regeneration

Kostprijsvergelijking varkenshouderij in Europees verband

De concurrentiepositie van de varkenshouderij in de Europese lidstaten hangt onder meer af van de kostprijs in relatie tot de opbrengstprijs. De gemiddelde kostprijs over alle bedrijven in Nederland én Denemarken bedroeg in 1995 f 3,47 per kg karkas. In Frankrijk was de gemiddelde kostprijs per kg karkas 5 cent hoger

Auditory attention influences trajectories of symbol–speech sound learning in children with and without dyslexia

The acquisition of letter–speech sound correspondences is a fundamental process underlying reading development, one that could be influenced by several linguistic and domain-general cognitive factors. In the current study, we mimicked the first steps of this process by examining behavioral trajectories of audiovisual associative learning in 110 7- to 12-year-old children with and without dyslexia. Children were asked to learn the associations between eight novel symbols and native speech sounds in a brief training and subsequently read words and pseudowords written in the artificial orthography. We then investigated the influence of auditory attention as one of the putative domain-general factors influencing associative learning. To this aim, we assessed children with experimental measures of auditory sustained selective attention and interference control. Our results showed shallower learning trajectories in children with dyslexia, especially during the later phases of the training blocks. Despite this, children with dyslexia performed similarly to typical readers on the post-training reading tests using the artificial orthography. Better auditory sustained selective attention and interference control skills predicted greater response accuracy during training. Sustained selective attention was also associated with the ability to apply these novel correspondences in the reading tests. Although this result has the limitations of a correlational design, it denotes that poor attentional skills may constitute a risk during the early stages of reading acquisition, when children start to learn letter–speech sound associations. Importantly, our findings underscore the importance of examining dynamics of learning in reading acquisition as well as individual differences in more domain-general attentional factors

Attentional modulation of neural sound tracking in children with and without dyslexia

Auditory selective attention forms an important foundation of children's learning by enabling the prioritisation and encoding of relevant stimuli. It may also influence reading development, which relies on metalinguistic skills including the awareness of the sound structure of spoken language. Reports of attentional impairments and speech perception difficulties in noisy environments in dyslexic readers are also suggestive of the putative contribution of auditory attention to reading development. To date, it is unclear whether non-speech selective attention and its underlying neural mechanisms are impaired in children with dyslexia and to which extent these deficits relate to individual reading and speech perception abilities in suboptimal listening conditions. In this EEG study, we assessed non-speech sustained auditory selective attention in 106 7-to-12-year-old children with and without dyslexia. Children attended to one of two tone streams, detecting occasional sequence repeats in the attended stream, and performed a speech-in-speech perception task. Results show that when children directed their attention to one stream, inter-trial-phase-coherence at the attended rate increased in fronto-central sites; this, in turn, was associated with better target detection. Behavioural and neural indices of attention did not systematically differ as a function of dyslexia diagnosis. However, behavioural indices of attention did explain individual differences in reading fluency and speech-in-speech perception abilities: both these skills were impaired in dyslexic readers. Taken together, our results show that children with dyslexia do not show group-level auditory attention deficits but these deficits may represent a risk for developing reading impairments and problems with speech perception in complex acoustic environments. Research Highlights: Non-speech sustained auditory selective attention modulates EEG phase coherence in children with/without dyslexia Children with dyslexia show difficulties in speech-in-speech perception Attention relates to dyslexic readers’ speech-in-speech perception and reading skills Dyslexia diagnosis is not linked to behavioural/EEG indices of auditory attention

Loudness and intelligibility of irrelevant background speech differentially hinder children's short story reading

Reading skills are usually assessed in silent conditions, but children often experience noisy educational settings. Effects of auditory distraction on children's reading skills remain relatively unexplored. The present study investigates the influence of two features of background speech—intelligibility and loudness—on children's reading speed and comprehension. Sixty‐three 8‐to‐10‐year‐old elementary school children performed a reading task in the context of single‐talker background speech. Background speech was either intelligible or unintelligible and presented at low (45–50 dB SPL) or moderate (65–72 dB SPL) sound intensity (here termed “loudness”). Results showed a differential effect of intelligibility and loudness, respectively affecting children's comprehension and reading speed. In addition, the intelligibility effect was larger in children with lower interference control, as assessed with an auditory Stroop task. Our findings provide evidence for the influence of different properties of background speech on children's text reading with implications for reading in everyday classroom environments

Cognitive complaints in patients with untreated obstructive sleep apnea versus patients with neurological and respiratory diseases:Prevalence, severity and risk factors

PurposeLittle is known about cognitive complaints (self-reported problems in cognitive functioning) in patients with Obstructive Sleep Apnea (OSA). We compared the prevalence and severity of cognitive complaints in patients with untreated OSA to patients with neurological and respiratory diseases. We also studied risk factors for cognitive complaints across these diseases, including OSA.MethodsWe used a convenience sample to compare untreated OSA patients (N = 86) to patients with stroke (N = 166), primary brain tumor (N = 197) and chronic obstructive pulmonary disease (COPD, N = 204) on cognitive complaints (Cognitive Failure Questionnaire, CFQ), anxiety and depression (Hospital Anxiety and Depression Scale, HADS) and cognitive impairments using neuropsychological tests. We combined all patient groups (OSA, stroke, brain tumor and COPD) and studied potential risk factors (demographic variables, anxiety, depression and cognitive impairments) for cognitive complaints across all patient groups using regression analysis.ResultsThe prevalence of cognitive complaints was higher in OSA patients and complaints of forgetfulness and distractibility were more severe compared to stroke and primary brain tumor patients, but similar to or lower than COPD patients. Regression analysis for the combined sample of all patient groups showed that cognitive complaints were most strongly associated with symptoms of anxiety and depression.ConclusionA high rate of OSA reported clinically significant cognitive complaints, comparable to other respiratory and neurological patients. Symptoms of anxiety and depression are important risk factors for cognitive complaints in patients with various neurological and respiratory diseases. Future studies should examine the relation between anxiety, depression and cognitive complaints in patients with OSA

Gezondheidsproblemen op zeugenbedrijven

Uit een enqulte op 438 zeugenbedrijven bleek dat op meer dan de helft van die bedrijven problemen voorkomen bij de gespeende biggen bij vijf van tien onderscheiden aandoeningen

Gezondheidsmanagement op zeugenbedrijven: de geenqulteerde bedrijven

In 1995 is op 438 zeugenbedrijven een enqulte uitgevoerd naar het gezondheidsmanagement op het bedrijf. Varkenshouders verschilden onderling in hun opvattingen over het nut van bepaalde maatregelen ter voorkoming van ziekte-uitbraak

Ectopic expression of PtaRHE1, encoding a poplar RING-H2 protein with E3 ligase activity, alters plant development and induces defence-related responses

RING (really interesting new gene)-H2 domain-containing proteins are widely represented in plants and play important roles in the regulation of many developmental processes as well as in plant–environment interactions. In the present report, experiments were performed to unravel the role of the poplar gene PtaRHE1, coding for a RING-H2 protein. In vitro ubiquitination assays indicate a functional E3 ligase activity for PtaRHE1 with the specific E2 ubiquitin-conjugating enzyme UbcH5a. The overexpression of PtaRHE1 in tobacco resulted in a pleiotropic phenotype characterized by a curling of the leaves, the formation of necrotic lesions on leaf blades, growth retardation, and a delay in floral transition. The plant gene expression response to PtaRHE1 overexpression provided evidence for the up-regulation of defence- and/or programmed cell death-related genes. Moreover, genes coding for WRKY transcription factors as well as for mitogen-activated protein kinases, such as wound-induced protein kinase (WIPK), were also found to be induced in the transgenic lines as compared with the wild type. In addition, histochemical β-glucuronidase staining showed that the PtaRHE1 promoter is induced by plant pathogens and by elicitors such as salicylic acid and cellulase. Taken together, these results suggest that the E3 ligase PtaRHE1 plays a role in the ubiquitination-mediated regulation of defence response, possibly by acting upstream of WIPK and/or in the activation of WRKY factors