Computational Decision Support System for ADHD Identification

Machine Intelligence Research - Attention deficit/hyperactivity disorder (ADHD) is a common disorder among children. ADHD often prevails into adulthood, unless proper treatments are facilitated to...     

Polymer on Top: Current Limits and Future Perspectives of Quantitatively Evaluating Surface Grafting

Well‐defined polymer strands covalently tethered onto solid substrates determine the properties of the resulting functional interface. Herein, the current approaches to determine quantitative grafting densities are assessed. Based on a brief introduction into the key theories describing polymer brush regimes, a user's guide is provided to estimating maximum chain coverage and—importantly—examine the most frequently employed approaches for determining grafting densities, i.e., dry thickness measurements, gravimetric assessment, and swelling experiments. An estimation of the reliability of these determination methods is provided via carefully evaluating their assumptions and assessing the stability of the underpinning equations. A practical access guide for comparatively and quantitatively evaluating the reliability of a given approach is thus provided, enabling the field to critically judge experimentally determined grafting densities and to avoid the reporting of grafting densities that fall outside the physically realistic parameter space. The assessment is concluded with a perspective on the development of advanced approaches for determination of grafting density, in particular, on single‐chain methodologies.     

Methacrylate hydrogels reinforced with bacterial cellulose

Composite hydrogels consisting of nanofibrous bacterial cellulose (BC) embedded in a biocompatible polymeric matrix of various methacrylates were synthesized by UV polymerization using the ‘ever‐wet’ technique. The effect of monomer(s) type and ratio, system dilution at polymerization, monomer(s) hydrophilicity, crosslink density and cellulose/hydrogel ratio was investigated. The effect of BC reinforcement on equilibrium swelling depends on whether the neat gel swells more when brought into contact with water. The major improvement achieved by introduction of 1%–2% BC concerns mechanical properties. Compared with neat gels, the storage shear modulus G′ increased by a factor 10‐20, and the loss part G″ also rose significantly. The compression modulus ranged from 2 to 5.5 MPa for composites swollen to equilibrium (20‐70 wt% water). The BC‐hydrogel composites are considered for application in the tissue engineering area. Copyright © 2012 Society of Chemical Industry     

Age-dependent MRI-detected lesions at early stages of transient global ischemia in rat brain

Although ischemic stroke has higher incidence and severity in aged than in young humans, the age factor is generally neglected in ischemia animal models. This study was aimed at comparing age-dependent effects at early stages of transient global cerebral ischemia (TGCI) in rats. TGCI was induced in two groups of rats (3–6 and 20–24 months old, respectively) by exposure to 15% oxygen and 15 min occlusion of the two common carotid arteries. Brains were analysed in vivo by MRI–apparent diffusion coefficient (ADC) and T₂ maps–at 1–3 h post-TGCI and in vitro by histochemical examination of triphenyltetrazolium chloride (TTC)-stained slices. At 1–3 h post-TGCI, a higher incidence of lesions was found in aged than in young rats especially in the hippocampus and cortex (occipital plus parietal) but not in the thalamus. The lesioned regions showed lower ADC values in aged than in younger rats. The most substantial ADC decreases were associated with enhanced spin-spin relaxation and lower TTC staining. The different responses of the two age groups support the use of aged animals for investigations on different ischemia models. Our model of brain ischemia appears appropriate for further studies including drug effects.     

Transient global brain ischemia in young and aged rats: differences in severity and progression, but not localisation, of lesions evaluated by magnetic resonance imaging

A model of transient global brain ischemia consisting of bilateral occlusion of common carotid arteries for 10 min and mild hypoxia (15% O₂−85% N₂) for 20 min was studied by means of MRI in young and aged Fischer 344 rats (3–4 and 24–26 months, respectively). Ischemia was assessed by full suppression of spontaneous EEG activity, which reappeared and normalized similarly in the two age-groups. The survival of young with respect to aged rats was considerably higher both at 24 h (20/20, i.e. 100% vs 12/16, i.e. 75%) and at 48 h (16/20, i.e. 80% vs 6/16, i.e. 38%). The localisation of brain lesions, their severity and progression were evaluated by a diffusion-weighted MRI (DWI) sequence at 24 and 48 h post-ischemia. There were no DWI-detectable lesions in eight out of 20 young and two out of 12 aged rats. The localisation of DWI-detected lesions was rather similar in rats of the two age-groups. In fact, the cerebral cortex, mainly parietal, occipital and temporal lobes were damaged in 83% of young and 90% of aged rats. The respective percentages for the thalamus were 83 and 60%, for the striatum 58 and 50%, and for the hippocampus 25 and 30%. The lesions present in the cerebral cortex and the thalamus were considerably more severe in aged than in young rats. In conclusion, in spite of similar localisation of ischemic lesions in the two age-groups, their incidence was higher, appearance more rapid and severity more pronounced in aged with respect to young rats. This resulted in a considerably higher mortality of the former. The overall data indicate that the age issue is very important in experimental ischemia research.     

Ground Water Flow Modelling Applications in Mining Hydrogeology

Some specific features and problems of numerical modelling applications in mining environment are briefly discussed and three modelling case studies are presented. Two of the applications are aimed at mine dewatering problems in active coal mines. The first represents the underground hard coal mining region in the Czech part of the Upper Silesian Coal Basin. The second example is focussed on optimisation of the dewatering regime of open pit mining of brown coal in the Most sub-basin of the North Bohemian Coal Basin. The third example describes how mathematical modelling can be applied to solve issues associated with the intensive use of mine waters from the flooded Olsi-Drahonin mine as a source of uranium to shorten the time necessary for the purification of mine waters discharged into watercourses.     

A Natural Algacide from Soft Coral Sinularia flexibilis (Coelenterata, Octocorallia, Alcyonacea)

A crude lipophilic extract and specific pure metabolites of the soft coral Sinularia flexibilis have been examined for algacidal properties both in laboratory and field experiments. Laboratory algal bioassays, in which cultures of the common fouling alga Ceramium codii were incubated with six different diterpenes isolated from S. flexibilisrevealed that 11-episinulariolide exhibits strong algacidal properties. Field experiments carried out with treated settlement tiles confirmed the laboratory findings and provided evidence for the algacidal properties of 11-episinulariolide against several other common reef algae. Sinulariolide, which had previously been reported to inhibit the growth of unicellular algae, was approximately one third as effective as its stereoisomer 11-episinulariolide in the laboratory growth inhibition bioassay and showed no significant algacidal properties at the concentrations used in the field experiments.     

Chemical denaturation and modification of ovalbumin alters its dependence on ubiquitin conjugation for class I antigen presentation

Class I presentation of microinjected native OVA by a temperature-sensitive ubiquitin conjugation mutant, ts85, but not wild-type murine cells, was markedly inhibited following incubation at a nonpermissive temperature. In contrast, the nonpermissive temperature did not affect class I presentation of a minimal OVA peptide expressed in the cytosol. Therefore, these results provide a second example in which a temperature sensitive mutation in the ubiquitin conjugation pathway inhibits MHC class I presentation of native OVA. Surprisingly, incubation at the nonpermissive temperature did not inhibit class I presentation of chemically denatured and alkylated OVA microinjected into the cytosol of mutant cells. Similarly, the presentation of endogenously synthesized OVA (which is expressed from a recombinant vaccinia virus and, presumably, is misfolded in the cytosol) was also not inhibited in both mutant cell lines. Methylation of the lysine groups in denatured OVA, which blocks ubiquitin conjugation, reduced but did not eliminate the presentation of denatured OVA, providing evidence for both ubiquitin-dependent and ubiquitin-independent pathways for class I presentation. In contrast, a proteasome inhibitor blocked class I presentation of all forms of OVA, while a control peptide aldehyde was not inhibitory. These results indicate that modification of the structure of a protein can influence its requirements for ubiquitin conjugation for efficient class I presentation, with the key alteration possibly being the loss of proper conformation. However, regardless of the form of the Ag, the proteasome appears to be required for generating peptides from both endogenously synthesized and microinjected OVA for class I presentation.     

Routes of immunization and antigen delivery systems for optimal mucosal immune responses in humans

Numerous experiments performed in humans and animals have revealed that stimulation of mucosal lymphoid inductive sites such as intestinal Peyer's patches results in parallel immune responses manifested by the appearance of S-IgA antibodies in the external secretions of remote glands. However, recent experiments suggest that inductive sites associated with the upper respiratory tract, rectum, and perhaps genital tract may also function as sources of lymphoid cells that populate, with some selectivity, certain remote mucosal effector sites. Furthermore, antigen-specific IgA antibodies can be induced in certain secretions (e.g., female genital tract) not only by immunization in the vicinity of corresponding mucosal tissues (e.g., vagina and rectum) but also by oral and especially intranasal immunization. The ineffectiveness of simple delivery of soluble antigens to mucosal membranes for immunization has stimulated extensive studies of strategies for effective delivery systems that would (a) increase the antigen absorption, (b) prevent its degradation, and (c) skew the outcome of immunization to a desired goal (protective response to infectious diseases vs. tolerance; B vs. T cell responses; mucosal vs. systemic). The induction of immune responses at a desired mucosal site can be accentuated with the use of a suitable antigen-delivery system including relevant bacterial or viral vectors, edible transgenic plants expressing microbial antigens, incorporation of antigens in biodegradable microspheres or liposomes, and linkage or coadministration of antigens with cholera toxin B subunit. However, only a few antigen-delivery systems extensively used in animal experimentation have been evaluated for their efficacy in humans. The combination of various immunization routes and the use of suitable antigen-delivery systems may accomplish an important task-the induction of mucosal immune responses at a location relevant to the site of entry of a given pathogen.     

Factors that influence the further survival of patients who survive for five years after the diagnosis of cancer in childhood or adolescence

Acute confusional states and agitated delirium are among the most common psychopathologic disorders in the elderly. However, they are rarely reported in the course of infarcts in the territory of the posterior cerebral artery. This study involving thirteen patients aged more than 65 years suggests that acute confusional states from posterior cerebral artery infarcts are less rare than usually thought, although the diagnosis may be difficult during the acute phase. The risk factors are no different from those observed for infarcts in other cortical areas, suggesting that this syndrome is due to structural damage of the brain rather than the other, usual causes of confusion in the elderly (intoxications, dysmetabolic diseases or dementia). The recognition of acute confusional states from posterior cerebral artery infarcts and its distinction from other causes of confusion is important in elderly patients because of the different diagnostic, prognostic and therapeutic implications involved.