Drug loading capacity of microporous β-pyrophosphate crystals

Periodontitis and peri-implantitis are two characteristic examples where bacterial infections compromise the healing of dental tissues. Drug eluting scaffolds are a potential solution to this problem but their fabrication requires suitable biomaterials with significant drug loading capacity and regenerative potential to support new tissue formation. With this aim, porous β-pyrophosphate crystals having a micro-pore area of 2.59 m2/g and an average pore diameter of 65 nm, have been obtained by the heat treatment of brushite (at 780 °C). To demonstrate the drug loading potential of the mineral, experiments with chloramphenicol have been conducted. After tests with four common bacteria, the drug loaded mineral was shown to have enhanced antibacterial properties, particularly towards E. coli (74% growth inhibition) and S. aureus (48% growth inhibition). Taking into account β-pyrophosphate's significant role in hard tissue mineralisation and the capability to tailor crystal micro-porosity characteristics by controlled heat treatment, the mineral can be considered as an ideal biomaterial for localised drug delivery in dental applications

Antibacterial properties and regenerative potential of Sr²+ and Ce³+ doped fluorapatites; a potential solution for peri-implantitis

Scaffolds and implants in orthopaedics and regenerative dentistry usually fail because of bacterial infections. A promising solution would be the development of biomaterials with both significant regenerative potential and enhanced antibacterial activity. Working towards this direction, fluorapatite was synthesised and doped with Sr²+ and Ce³+ ions in order to tailor its properties. After experiments with four common bacteria (i.e. E. Coli, S. Aureus, B. Subtilis, B. Cereus), it was found that the undoped and the Ce³+ doped fluorapatites present better antibacterial response than the Sr²+ doped material. The synthesised minerals were incorporated into chitosan scaffolds and tested with Dental Pulp Stem Cells (DPSCs) to check their regenerative potential. As was expected, the scaffolds containing Sr²+-doped fluorapatite, presented high osteoconductivity leading to the differentiation of the DPSCs into osteoblasts. Similar results were obtained for the Ce³+-doped material, since both the concentration of osteocalcin and the RUNX2 gene expression were considerably higher than that for the un-doped mineral. Overall, it was shown that doping with Ce³+ retains the good antibacterial profile of fluorapatite and enhances its regenerative potential, which makes it a promising option for dealing with conditions where healing of hard tissues is compromised by bacterial contamination

A numerical method to solve higher-order fractional differential equations

In this paper, we present a new numerical method to solve fractional differential equations. Given a fractional derivative of arbitrary real order, we present an approximation formula for the fractional operator that involves integer-order derivatives only. With this, we can rewrite FDEs in terms of a classical one and then apply any known technique. With some examples, we show the accuracy of the method

Learning difficulties screening web application

Learning disabilities is a generic term that refers to a heterogeneous group of disorders. The aim of the present pilot study was to examine the efficacy of a new web neurocognitive screening tool, the 'askisi' that was developed to provide a brief screening measure for learning difficulties. Participants were twenty children who had been initially identified with learning difficulties and a control group of twenty students' age- and sex-matched with the children with learning difficulties. Group members' ages range between 8 and 12 years old. The set of tasks which all children had to undergo included 10 test that examined children's rreading, spelling, arithmetic and cognitive skills. In our effort to enhance the aforementioned procedure we created a client-server web application that implements its core characteristics. The results indicated that children with learning difficulties had significantly less correct responses in eight of the ten tasks, of our web screening test, compared with the control group, suggesting that the difference between the two groups could be practically important. Although time latency of learning disabled children was larger than their typical developing schoolmates (see Table 2), this difference did not reach statistical significance in five of the nine tasks measured. Overall, these results of this pilot study revealed strong convergent and discriminant evidence for the eight tasks of the 'askisi' screening measure, suggesting that this web application may provide a useful method to screen for learning difficulties in both research studies and clinical settings. © 2015 IEEE

Enhanced tetris legalization

Legalization and detailed placement methods for standard cell designs, are two of the most notable topics in current VLSI research. Being the final steps in a classic placement procedure they must be efficient in terms of the delay overhead they introduce to the overall design flow and the quality of the final solution. In this paper we present a combined solution of the aforementioned steps, based on Tetris a particular simple and fast legalization algorithm, that produces considerable results taking into account the tradeoff between total wirelength, total cell displacement and runtime. © 2016 ACM

The implementation of a web application for screening children with dyslexia

Developmental dyslexia is defined as an unexpected specific and persistent failure to acquire efficient reading skills despite conventional instruction, adequate intelligence and sociocultural opportunity. The main aim of the present research protocol was to construct a web screening battery of tests in order to screen children’s reading, orthographic and cognitive skills. The main hypothesis of the present study was that Greek students that were already diagnosed as dyslexic, shall present significantly lower scores. A total of sixty, right handed children (30 male and 30 female, age range 8–11 years old M = 8.93, SD = 0.83) participated in this study. Reading, cognitive and orthographic skills of children with dyslexia and typically achieving children were examined, using a battery that consisted of seven tasks. Subsequent analysis of variance revealed that the children with dyslexia had statistically significant (p < 0.01) lower mean scores of correct answers and larger latencies in all tasks compared to their average peers that participated at the control group. © Springer International Publishing AG 2017

Screening for disorders of mathematics via a web application

Dyscalculia is a neurodevelopmental disorder that affects the ability of a child to learn arithmetic. Dyscalculia appears despite normal intelligence, proper schooling, adequate environment, socioeconomic status and motivation. The first aim of the present research protocol was to construct a battery of tests that can be delivered by computer in order to screen children's arithmetic skills. Our second aim was to develop a web application screener for dyscalculia that assesses children aged from 8-11 years old and that, to the best of our knowledge, does not exist. The hypothesis of the present study was that Greek students that are already diagnosed by paper-and-pencil tests as dyscalculic, will present lower performance and higher time latencies in the tasks of the aforementioned web application screener. A total of sixty, right handed children (30 male and 30 female, age range 8-11 years old) participated in this study. The students with disorders in mathematics (N=30, 15 male and 15 female) had a statement of dyscalculia issued after assessment at a Centre of Diagnosis, Assessment and Support, as required by Greek Law. The comparison group (N=30) was formed by pupils who attended the same classes with dyscalculics, presented typical academic performance according to their teachers' ratings and had been matched for age and gender with the children with disorder in mathematics. Three tasks were used for evaluating children's arithmetic ability: a calculation task, a task that evaluated their skills in understanding mathematical terminology, and an arithmetic problem solving task. Statistical analysis revealed that children with dyscalculia had statistically significant lower mean scores of correct answers and larger time latencies in all tasks compared to their average peers that participated in the comparison group. In conclusion, it must be highlighted that the web application screener for dyscalculia used in this study was found to be a feasible instrument for first-pass screening services and referral. © 2017 IEEE

Novel poly(butylene succinate) nanocomposites containing strontium hydroxyapatite nanorods with enhanced osteoconductivity for tissue engineering applications

Three series of poly(butylene succinate) (PBSu) nanocomposites containing 0.5, 1 and 2.5 wt% strontium hydroxyapatite [Sr5(PO4)3OH] nanorods (SrHAp nrds) were prepared by in situ polymerisation. The structural effects of Sr5(PO4)3OH nanorods, for the different concentrations, inside the polymeric matrix (PBSu), were studied through high angle annular dark field scanning transmission electron microscopy (HAADF-STEM). HAADF-STEM measurements revealed that the SrHAp nanorods at low concentrations are dispersed inside the polymeric PBSu matrix while in 1 wt% some aggregates are formed. These aggregations affect the mechanical properties giving an enhancement for the concentration of 0.5 wt% SrHAp nrds in tensile strength, while a reduction is recorded for higher loadings of the nanofiller. Studies on enzymatic hydrolysis revealed that all nanocomposites present higher hydrolysis rates than neat PBSu, indicating that nanorods accelerate the hydrolysis degradation process. In vitro bioactivity tests prove that SrHAp nrds promote the formation of hydroxyapatite on the PBSu surface. All nanocomposites were tested also in relevant cell culture using osteoblast-like cells (MG-63) to demonstrate their biocompatibility showing SrHAp nanorods support cell attachment

Continuous hydrologic modelling for small and ungauged basins: A comparison of eight rainfall models for sub-daily runoff simulations

Continuous hydrologic modelling is a natural evolution of the event-based design approach in modern hydrology. It improves the rainfall-runoff transformation and provides the practitioner with more effective hydrological output information for risk assessment. However, this approach is still not widely adopted, mainly because the choice of the most appropriate rainfall simulation model (which is the core of continuous frameworks) for the specific aim of risk analysis has not been sufficiently investigated. In this paper, we test eight rainfall models by evaluating the performances of the simulated rainfall time series when used as input for a simplified continuous rainfall-runoff model, the COSMO4SUB, which is particularly designed for small and ungauged basins. The comparison confirms the capability of all models to provide realistic flood events and allows identifying the models to be further improved and tailored for data-scarce hydrological risk applications. The suggested framework is transferable to any catchment while different hydrologic and rainfall models can be used