Adherend thickness effect on the tensile fracture toughness of a structural adhesive using an optical data acquisition method

Adhesive bonding is nowadays a serious candidate to replace methods such as fastening or riveting, because of attractive mechanical properties. As a result, adhesives are being increasingly used in industries such as the automotive, aerospace and construction. Thus, it is highly important to predict the strength of bonded joints to assess the feasibility of joining during the fabrication process of components (e.g. due to complex geometries) or for repairing purposes. This work studies the tensile behaviour of adhesive joints between aluminium adherends considering different values of adherend thickness (h) and the double-cantilever beam (DCB) test. The experimental work consists of the definition of the tensile fracture toughness (GIC) for the different joint configurations. A conventional fracture characterization method was used, together with a J-integral approach, that take into account the plasticity effects occurring in the adhesive layer. An optical measurement method is used for the evaluation of crack tip opening and adherends rotation at the crack tip during the test, supported by a Matlab® sub-routine for the automated extraction of these quantities. As output of this work, a comparative evaluation between bonded systems with different values of adherend thickness is carried out and complete fracture data is provided in tension for the subsequent strength prediction of joints with identical conditions

Control of konzo in the Democratic Republic of Congo

Konzo is an upper motor neuron disease that causes irreversible paralysis of the legs mainly in children and young women^1,2^, due to consumption of large amounts of cyanogens from poorly processed cassava, the staple food of tropical Africa^3^. Konzo occurs in the Democratic Republic of Congo (DRC),Mozambique, Tanzania, Cameroon, Central African Republic and Angola. In March 2010 the wetting method, which removes cyanogens from cassava flour^4,5,6^, was taught to and used by the mothers of Kay Kalenge village. This reduced the total cyanide content of cassava flour to the FAO/WHO limit of 10ppm^7^. Cyanogen intake of school children, monitored by urinary thiocyanate analyses, decreased from mean values of 332 to 130 μmole/L. The percentage of urine samples that exceeded the danger level of about 350 μmole/L decreased from 26 in March 2010 to zero by May 2011. In 2009 there were many new cases of konzo, but none in 2010-2011. Konzo was first identified in1938 in Popokabaka area^8^ and it has now been prevented for the first time in the same area. This methodology is being used in three villages in Boko area and we believe it is the way to control konzo in tropical Africa

Using high density EEG to assess TMS treatment in patients with schizophrenia.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked DownloadWe present preliminary results from the ongoing study entitled "Icelandic AVH-TMS" which aim is to study the effectiveness of repetitive transcranial magnetic stimulation (rTMS) treatment for patients with schizophrenia and with persistent auditory verbal hallucinations (AVH) using symptoms and psychometric scales and high-density EEG system (256 channels). The aim of the present work was to describe cortical topography of the auditory evoked responses like P50 and N100-P300 complex in healthy participants and patients with schizophrenia and to define a robust methodology of signal quantification using dense-array EEG. Preliminary data is shown for three healthy participants and three patients in baseline conditions and for two patients we show the results recorded before and after 10 days rTMS treatment. Our results show differences in sensory gating (P50 suppresion) and a stronger N100-P300 response to rare audio stimulus after the treatment. Moreover we show the value of assessing brain electrical activity from high-density EEG (256 channels) analyzing the results in different regions of interest. However, it is premature and hazardous to assume that rTMS treatment effectiveness in patients with AVH can be assessed using P50 suppression ratio. Keywords: P300; P50; Transcranial magnetic stimulation; high density EEG; schizophrenia

Mechanical Characterization of Filler Modified ABS 3D Printed Composites Made via Fused Filament Fabrication

Rapid prototyping (also known as additive manufacturing, AM) is a quickly developing process with increasing new applications in a large variety of industrial sectors (i.e., aerospace, automotive, medical, among others.) However, despite the great advantage of a decoupled price to part complexity of an AM fabricated structure, the material properties (largely governed by filament material and printing parameters) still present a significant limiting factor. In this context, the development of new filament materials for a wider range of applications has great potential. In this study, the influence of micro-scale filler reinforcement (powders), both natural (curauá) and synthetic (glass fibre), in the fabrication of an Acrylonitrile Butadiene Styrene (ABS) filament was evaluated. The filler was controlled by weight fraction (~1%) and the filament was fabricated via extrusion. A commercially available 3D printer was used to print tensile and flexural specimens for mechanical characterization as per ASTM standards. The fracture morphology was analysed after tensile testing via optical microscopy in order to evaluate the effect of the fillers on the material deposition and void formation. No significant variation in the tensile properties was reported, except for the strain at failure, while more significant flexural strength variation was observed as a function of filler material. The fillers presented a significant effect on the void density of the fractured surface. It was demonstrated that this simple fabrication technique can generate novel filament materials that may enhance the mechanical properties or widen the range of application (e.g., faster decomposition times in nature for single-use plastics due to the hydrophilic nature of the natural filler and lower water absorption of the hydrophobic synthetic filler for marine environment applications)

P300 Analysis Using High-Density EEG to Decipher Neural Response to rTMS in Patients With Schizophrenia and Auditory Verbal Hallucinations.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked DownloadSchizophrenia is a complex disorder about which much is still unknown. Potential treatments, such as transcranial magnetic stimulation (TMS), have not been exploited, in part because of the variability in behavioral response. This can be overcome with the use of response biomarkers. It has been however shown that repetitive transcranial magnetic stimulation (rTMS) can the relieve positive and negative symptoms of schizophrenia, particularly auditory verbal hallucinations (AVH). This exploratory work aims to establish a quantitative methodological tool, based on high-density electroencephalogram (HD-EEG) data analysis, to assess the effect of rTMS on patients with schizophrenia and AVH. Ten schizophrenia patients with drug-resistant AVH were divided into two groups: the treatment group (TG) received 1 Hz rTMS treatment during 10 daily sessions (900 pulses/session) over the left T3-P3 International 10-20 location. The control group (CG) received rTMS treatment over the Cz (vertex) EEG location. We used the P300 oddball auditory paradigm, known for its reduced amplitude in schizophrenia with AVH, and recorded high-density electroencephalography (HD-EEG, 256 channels), twice for each patient: pre-rTMS and 1 week post-rTMS treatment. The use of HD-EEG enabled the analysis of the data in the time domain, but also in the frequency and source-space connectivity domains. The HD-EEG data were linked with the clinical outcome derived from the auditory hallucinations subscale (AHS) of the Psychotic Symptom Rating Scale (PSYRATS), the Quality of Life Scale (QoLS), and the Depression, Anxiety and Stress Scale (DASS). The general results show a variability between subjects, independent of the group they belong to. The time domain showed a higher N1-P3 amplitude post-rTMS, the frequency domain a higher power spectral density (PSD) in the alpha and beta bands, and the connectivity analysis revealed a higher brain network integration (quantified using the participation coefficient) in the beta band. Despite the small number of subjects and the high variability of the results, this work shows a robust data analysis and an interplay between morphology, spectral, and connectivity data. The identification of a trend post-rTMS for each domain in our results is a first step toward the definition of quantitative neurophysiological parameters to assess rTMS treatment. Keywords: P300; TMS (repetitive transcranial magnetic stimulation); brain connectivity; high-density EEG; schizophrenia; spectral analysis; temporal analysis.United States Department of Health & Human Services National Institutes of Health (NIH) - USA NIH National Institute of Neurological Disorders & Stroke (NINDS) Landspitali Scientific fund