647 research outputs found
Development of sustainable biodegradable lignocellulosic hemp fiber/polycaprolactone biocomposites for light weight applications
Biocomposites with poly(ε-caprolactone) (PCL) as matrix and lignocellulosic hemp fiber with varying average aspect ratios (19, 26, 30 and 38) as reinforcement were prepared using twin extrusion process. The influence of fiber aspect ratio on the water absorption behavior and mechanical properties are investigated. The percentage of moisture uptake increased with the aspect ratio, following Fickian behavior. The hemp fiber/PCL biocomposites showed enhanced properties (tensile, flexural and low-velocity impact). The biocomposite with 26 aspect ratio showed the optimal properties, with flexural strength and modulus of 169% and 285% respectively, higher than those of neat PCL. However, a clear reduction on the mechanical properties was observed for water-immersed samples, with reduction in tensile and flexural moduli for the aspect ratio of 26 by 90% and 62%, respectively than those of dry samples. Summarily, the optimal sample provides an eco-friendly alternative to conventional, petroleum-based and non-renewable composites for various applications.Peer reviewedFinal Accepted Versio
Production and purification of extreme xylanase from Aspergillus flavus AUMC 10331 in sub-merged fermentation
Xylan, extracted from oat spelts in a previous work, was assayed by HPLC and used as carbon source for the production of xylanase from Aspergillus flavus AUMC 10331. The produced xylanase was purified using ion exchange resin (IR-120 EP) and gel filtration column of Sephadex G-75 and Sephadex G-100. The purified xylanase showed total activity of 5.5 IU/ml and specific activity of 687.5 IU/mg, and the enzyme purified 156.75 fold with 4.43 % yield. The highest activity at pH 7.0 and 10.5 indicating two xylanases with the most interesting one with a maximum activity at pH 10.5 and 65 °C. The enzyme activity was greatly stimulated by 5 mM of FeSO4 and CuSO4, while slightly inhibited by other metal ions. Km and Vmax were determined as 8.36 mg/ml and 172.4 IU/min respectively.
DOI: http://dx.doi.org/10.5281/zenodo.258610
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A critical review on the contributions of chemical and physical factors toward the nucleation and growth of large-area graphene
Since the first isolation of graphene over a decade ago, research into graphene has exponentially increased due to its excellent electrical, optical, mechanical and chemical properties. Graphene has been shown to enhance the performance of various electronic devices. In addition, graphene can be simply produced through chemical vapor deposition (CVD). Although the synthesis of graphene has been widely researched, especially the CVD growth method, the lack of understanding of various synthetic parameters still limits the fabrication of large-area and defect-free graphene films. This report critically reviews various parameters affecting the quality of CVD grown graphene to understand the relationship between these parameters and thechoice of metal substrates and to provide a point of reference for future studies of large-area, CVD-grown graphene
W/M serrated osteotomy for infantile Blount’s disease in Ghana: Short‑term results
Purpose: The W/M serrated high tibial osteotomy is a not frequently described surgical technique for simultaneously correcting the varus and torsional deformity in patients with Blount’s disease. Without the need for internal fixation, this surgical treatment is well suited for developing countries. This study describes the short‑term results of the bilateral and unilateral W/M serrated osteotomy in patients with infantile Blount’s disease.Methods: Between May 2008 and January 2013, 52 patients were treated with uni‑ (n = 22) or bi‑lateral (n = 30) W/M serrated osteotomy of the proximal tibia due to a tibial varus deformity in two district hospitals in Ghana. Other causes than infantile Blount’s disease were excluded from the analysis. Pre‑ and post‑operative clinical and radiological measurements were done, and complications were monitored up to 12 weeks after surgery.Results: Seventeen patients (five males, 12 females; mean age 4.9 [standard deviation: 2.10]) were included, which underwent a total of 25 W/M serrated osteotomies. The femorotibial angle was corrected from 34.1° ([mean] range: 6 68°) to − 7.1° ([mean] range: −28–5°). Only one patient had developed a wound infection, and all reached full consolidation.Conclusions: The W/M serrated osteotomy seems a profitable alternative technique for treating the varus and torsional deformity in patients with Blount’s disease in the circumstances of developing countries. The short‑term outcomes are good and promising with a low complication rate and good consolidation. Long‑term follow‑up results of these patients are needed to observe possible complications.Level of Evidence: IV, therapeutic case series.Keywords: Blount’s disease, complications, infantile, osteotomy, tibia var
Validation of a specific phobia questionnaire by University students in Malaysia
Specific phobia is a subcategory of anxiety disorders that remains poor understanding due to inadequate screening tools. This study aimed to develop and validate a new Specific Phobia Questionnaire (SPQ). This SPQ was developed based on literature reviews and inputs from related experts for content validity. The SPQ questionnaire consisted of 14 items and after content validity and face validity testing procedure, 12 items were chosen for the final questionnaire. The questionnaire was then distributed via Google form to university students in Klang Valley. A total of 267 students participated in this study with 70.8% were female with mean age of 23.28 (Standard deviation of 4.98) years. Validity analysis using exploratory factor analysis from the final study indicated that the Kaiser-Meyer- Olkin value was 0.77 and extracted three domains; animals, blood injection injury and situational-environment. Reliability analysis showed that Cronbach’s α values were 0.84, 0.86, 0.78 and 0.72 for the total items, animal, blood injection injury and situational-environment domains, respectively. The newly developed SPQ showed good reliability and validity for evaluating specific phobia
Locked-in syndrome following a king cobra (Ophiophagus hannah) envenomation
The incidence of envenoming from king cobra, Ophiophagus hannah in human is relatively rare. Its venom acts on the postsynaptic region of the neuromuscular junction causing descending flaccid paralysis. Locked-in syndrome is a clinical state of inability to provide motor response in a conscious patient. Many reported cases of locked-in syndrome following neurotoxic snake-bite mimics brain death. We report a case of a middle aged man who presented with progressive neurological deficit following a king cobra bite over his right arm. He had local and systemic neurotoxic envenoming. His condition deteriorated, and was intubated and ventilated in the emergency department. He received a total of 33 vials of the Ophiophagus hannah monospecific antivenom and subsequently recovered well with no neurological deficit. Retrospectively, he was able to recall the events and while he was lying paralysed and intubated under minimal sedation in the intensive care unit. He described it as a terrifying and painful experience. This case highlights the rare presentation of locked-in syndrome following a systemic envenoming from a king cobra bite. It is important to differentiate neurotoxic snake envenoming lock-in syndrome from brain dead. Patients are unable to respond to physical pain and require adequate analgesia. A patient suffering this highly distressing experience may require psychological support
Development and characterisation of novel electrospun polylactic acid/tubular clay nanocomposites
A novel material formulation method of polylactic acid /tubular clay nanocomposites via electrospinning was introduced and the important processing parameters such as solution concentration, clay loading, material feed rate were particularly investigated. The hybrid fibre diameter, the clay dispersability and the thermal properties of such nanocomposites were then characterised by using the scanning electron microscopy, wide-angle X-ray diffraction and differential scanning calorimetry, respectively, to establish a fundamental structure–property relationship for the future application
Quantitative trait loci conferring grain mineral nutrient concentrations in durum wheat 3 wild emmer wheat RIL population
Mineral nutrient malnutrition, and particularly
deficiency in zinc and iron, afflicts over 3 billion people
worldwide. Wild emmer wheat, Triticum turgidum ssp.
dicoccoides, genepool harbors a rich allelic repertoire for
mineral nutrients in the grain. The genetic and physiological
basis of grain protein, micronutrients (zinc, iron,
copper and manganese) and macronutrients (calcium,
magnesium, potassium, phosphorus and sulfur) concentration
was studied in tetraploid wheat population of 152
recombinant inbred lines (RILs), derived from a cross
between durum wheat (cv. Langdon) and wild emmer
(accession G18-16). Wide genetic variation was found
among the RILs for all grain minerals, with considerable
transgressive effect. A total of 82 QTLs were mapped for
10 minerals with LOD score range of 3.2–16.7. Most QTLs
were in favor of the wild allele (50 QTLs). Fourteen pairs
of QTLs for the same trait were mapped to seemingly
homoeologous positions, reflecting synteny between the A
and B genomes. Significant positive correlation was found
between grain protein concentration (GPC), Zn, Fe and Cu,
which was supported by significant overlap between the
respective QTLs, suggesting common physiological and/or
genetic factors controlling the concentrations of these
mineral nutrients. Few genomic regions (chromosomes 2A,
5A, 6B and 7A) were found to harbor clusters of QTLs for
GPC and other nutrients. These identified QTLs may
facilitate the use of wild alleles for improving grain
nutritional quality of elite wheat cultivars, especially in
terms of protein, Zn and Fe
A one-stop perineal clinic: our eleven-year experience.
INTRODUCTION AND HYPOTHESIS: The perineal clinic is a dedicated setting offering assessment for various childbirth-related presentations including obstetric anal sphincter injuries (OASIs), perineal wound complications, pelvic floor dysfunction and other conditions such as female genital mutilation(FGM). We describe the clinical presentation and outcomes of women from a tertiary perineal clinic based on data collected over an 11-year period. METHODS: This is a retrospective observational study. A one-stop outpatient service was offered to all women who sustained OASIs (postnatally and antenatally in a subsequent pregnancy), perineal complications (within 16Â weeks postpartum), FGM and/or peripartum symptoms of urinary/anal incontinence or prolapse. Assessment included history with validated questionnaires, examination and anal manometry and endoanal ultrasound when appropriate. Outcomes were compared among different grades of OASIs. Management of each type of presentation was reported with outcomes. RESULTS: There were 3254 first attendance episodes between 2006 and 2016. The majority (58.1%) were for OASIs, followed by perineal wound complications. Compared to the lower grades, the higher grades of OASI were associated with poorer outcomes in terms of symptoms, investigations and complications. Women with OASIs had unrelated symptoms such as urinary incontinence, perineal pain and wound infections that needed further intervention. A high proportion(42%) of wound complications required further specialist management. CONCLUSION: We describe a dedicated, one-stop perineal clinic model for antenatal and postnatal women for management of perineal and pelvic floor disorders. This comprehensive and novel data will enable clinicians to better counsel women regarding of outcomes after OASI and focus training to minimize risks of morbidities
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