Identifying what makes a good question in a mechanics diagnostic test

Many students entering engineering degrees encounter problems with the mathematics involved. More recently, research has shown that freshers may have insuffi cient knowledge of mechanics. In order to assess this, the authors created and administered a multiple-choice mechanics diagnostic test. This paper gives details of the test, and evaluates, using item analysis, how students performed on the questions and on the topics assessed by it. It also makes recommendations for devising questions which allow a diagnostic test to discriminate between students

Predicting performance of 1st year engineering students and the importance of assessment tools therein

In recent years, the increase in the number of people entering university has contributed to a greater variability in the background of those beginning programmes. Consequently, it has become even more important to understand a student’s prior knowledge of a given subject. Two main reasons for this are to produce a suitable first year curriculum and to ascertain whether a student would benefit from additional support. Therefore, in order that any necessary steps can be taken to improve a student’s performance, the ultimate goal would be the ability to predict future performance. A continuing change in students’ prior mathematics (and mechanics) knowledge is being seen in engineering, a subject that requires a significant amount of mathematics knowledge. This paper describes statistical regression models used for predicting students’ first year performance. Results from these models highlight that a mathematics diagnostic test is not only useful for gaining information on a student’s prior knowledge but is also one of the best predictors of future performance. In the models, it was also found that students’ marks could be improved by seeking help in the university’s mathematics learning support centre. Tools and methodologies (e.g. surveys and diagnostic tests) suitable for obtaining data used in the regression models are also discussed

Engineering students' knowledge of mechanics upon arrival: expectation and reality

In recent years there has been an increasing awareness of a lack of knowledge of mechanics amongst engineering students entering English universities. In this paper, the authors investigate the level of knowledge of mechanics which lecturers commonly expect from students entering university. They also review students’ actual knowledge upon arrival. This research was carried out by implementing several research methods, including a survey of 497 schools in England; a survey of over 1,000 engineering students; results from a mechanics diagnostic test sat by 451 engineering students and a survey and follow-up interviews of academic staff. Findings from these indicate that there is a considerable difference between academic expectation and the reality of students’ prior knowledge of mechanics

Evaluation of the flexural properties and failure evolution of a hybrid composite manufactured by automated dry fibre placement followed by liquid resin infusion

The market for composites is developing rapidly due to the widespread general requirement for lightweight design in various industries. However, the proliferation of fibre-reinforced composites is limited partly due to the lack of ductility associated with these materials. Hybridisation of fibres has emerged as an important strategy to increase the ductility of polymer composite materials. In the present work, water based dispersion was used to develop a dry fibre carbon tape and a hybrid glass/carbon tape which are both compatible with automated deposition techniques. Dry fibre preforms were manufactured using laser-assisted dry fibre placement (DFP) and laminates were subsequently manufactured using vacuum assisted liquid resin infusion. The hybrid composite exhibited both higher flexural strength (8%) and higher strain-to-failure (58%) relative to the carbon based laminate. To understand the failure modes, X-ray micro-computed tomography was used in conjunction with interrupted flexural tests to monitor the evolution of damage. The progressive failure analysis revealed that for hybrid composites, damage propagation was delayed due to the staggered arrangement of glass and carbon fibres. The majority of damage in the hybrid composite was located in the carbon fibres tows

Influence of environmental conditioning on mechanical properties of carbon dry fibre preformed thermoplastic matrix composites manufactured via automated placement-resin infusion process

In the present work, dry fibre placement (DFP) of co-polyamide based carbon fibre spreadtow bindered tape for fabrication of thermoplastic acrylic resin composites was explored. The DFP followed by vacuum assisted liquid resin infusion (LRI) is expected to be an alternative process to traditional preforming approaches. This research work looks at the influence of water immersion on the performance of the composites was studied. The thermo mechanical behaviour of the aged and unaged samples were carried out as a function of temperature. The flexural strength of aged samples dropped by 4 and 17% after one and three months respectively. However, no significant changes were observed in flexural modulus compared to unaged. The interlaminar shear strength decreased by 19% and 35% after one month immersion and three months immersion. The results were complimented by fractographic and morphological studies

Gender and age-related cell compositional differences in C57BL/6 murine adipose tissue stromal vascular fraction

<p>Adipose tissue is now recognized as a functional organ that contains cellular heterogeneity and diversity within anatomical depots. The stromal vascular fraction (SVF) of adipose contains endothelial progenitors, fibroblasts, lymphocytes, monocyte/macrophages, pericytes, pre-adipocytes, and stromal/stem cells, among others. In recent years, there has been a growing appreciation of the influence of age and gender in the field of stem cell biology. Yet few studies have evaluated the influence of biological age or sex on either SVF cell heterogeneity or immunophenotype. To address this issue, the current study has compared the flow cytometric characteristics between murine SVF of inguinal (iWAT), epidydimal (eWAT), and brown (BAT) adipose tissue of male and female, as well as young (6–8 week) and middle-aged (8–12 month) male C57BL/6 mice. Murine gender comparisons revealed male iWAT expressed higher percentages of leukocyte and CD34⁺ ASC-like sub-populations than female iWAT. Murine age comparisons revealed younger male iWAT, eWAT, and BAT SVF all contained a significantly higher percentage of pre-adipocytes, HSC-like cells, CD25⁻, and FoxP3⁺ T-regulatory cells compared to SVF from middle-aged male mice. These findings highlight the potential contribution of biological variables on adipose-derived cell applications and experimental outcomes.</p

Mechanical evaluation and failure analysis of composite laminates manufactured using automated dry fibre tape placement followed by liquid resin infusion

Automated tape placement is seen as a promising technique for the manufacture of net-shape dry fibre preforms using carbon fibre tapes. However, most of the dry fibre tapes (DFT) available on the market are proprietary and aimed mainly at the aerospace sector. In the current study, two different binders (polyurethane and phenoxy water based binder) were used to coat and hence stabilise the carbon fibre tows. A net shaped preform was manufactured using Laser-Assisted Dry Fibre Tape Placement (LDFTP) and subsequently infused by vacuum assisted liquid resin infusion. The mechanical properties of the resulting laminates were compared to the laminates where the preform was manually laid up by hand with and without a coating (baseline). Failure mechanism analysis was carried out using scanning electron microscopy (SEM). The LDFTP process improved cured ply thickness (17–20% reduction) and fibre volume fraction (+9%). Interlaminar shear strength (ILSS) showed a significant improvement of 35–48%. However, only laminates manufactured using phenoxy coated LDFTP manufactured preforms showed comparable flexural strength to the uncoated baseline. Flexural modulus reduced in all cases. Further optimisation of binder content and process parameters (layup rate, consolidation temperature) is required for high speed deposition, better consolidation and improvements in mechanical properties

Engineered Biocompatible Nanoparticles for <i>in Vivo</i> Imaging Applications

Iron−platinum alloy nanoparticles (FePt NPs) are extremely promising candidates for the next generation of contrast agents for magnetic resonance (MR) diagnostic imaging and MR-guided interventions, including hyperthermic ablation of solid cancers. FePt has high Curie temperature, saturation magnetic moment, magneto-crystalline anisotropy, and chemical stability. We describe the synthesis and characterization of a family of biocompatible FePt NPs suitable for biomedical applications, showing and discussing that FePt NPs can exhibit low cytotoxicity. The importance of engineering the interface of strongly magnetic NPs using a coating allowing free aqueous permeation is demonstrated to be an essential parameter in the design of new generations of diagnostic and therapeutic MRI contrast agents. We report effective cell internalization of FePt NPs and demonstrate that they can be used for cellular imaging and <i>in vivo</i> MRI applications. This opens the way for several future applications of FePt NPs, including regenerative medicine and stem cell therapy in addition to enhanced MR diagnostic imaging

Additional file 1: of Predictors of high-cost hospitalization in the treatment of acute coronary syndrome in Asia: findings from EPICOR Asia

Table S1. List of participating sites and principal investigators. Table S2. Mean (95% CI) individual center-specific cost ($INT) per procedure by country*. (DOCX 34 kb

Discovery and Optimization of a Novel Series of Potent Mutant B‑Raf^V600E Selective Kinase Inhibitors

B-Raf represents an attractive target for anticancer therapy and the development of small molecule B-Raf inhibitors has delivered new therapies for metastatic melanoma patients. We have discovered a novel class of small molecules that inhibit mutant B-Raf^V600E kinase activity both in vitro and in vivo. Investigations into the structure–activity relationships of the series are presented along with efforts to improve upon the cellular potency, solubility, and pharmacokinetic profile. Compounds selectively inhibited B-Raf^V600E in vitro and showed preferential antiproliferative activity in mutant B-Raf^V600E cell lines and exhibited selectivity in a kinase panel against other kinases. Examples from this series inhibit growth of a B-Raf^V600E A375 xenograft in vivo at a well-tolerated dose. In addition, aminoquinazolines described herein were shown to display pERK elevation in nonmutant B-Raf cell lines in vitro