Ballistic Performance of Alumina and Zirconia-toughened Alumina Against 7.62 Armour Piercing Projectile

A study was carried out to compare the ballistic performance of high purity alumina and zirconia-toughened alumina (ZTA) using depth of penetration (DoP) test configuration against 7.62 mm armour piercing (AP) ammunition. The effect of tile thickness on the differential efficiency factor (DEF) was studied for tile thickness in the range of 3 mm to 6 mm for alumina tiles and 3 mm to 5 mm for ZTA tiles. The DEF is found to increase as tile thickness increases. An analysis on the failed shots showed that the residual shot weight does not follow a single linear relationship with ceramic tile thickness unlike the residual DoP for all thicknesses of tiles. Post-ballistic analysis on ceramic powder for particle size distribution was carried out and the results are presented.Defence Science Journal, Vol. 64, No. 5, September 2014, pp.477-483, DOI:http://dx.doi.org/10.14429/dsj.64.674

Toughening and creep in multiphase intermetallics through microstructural control

The lack of engineering ductility in intermetallics has limited their structural applications, in spite of their attractive specific properties at high temperatures. Over the last decade, research in intermetallics has been stimulated by the discovery of remarkable ductilisation mechanisms in these materials. It has however often been the case that the process of ductilisation or toughening has also led to a decrease in high temperature properties, especially creep. In this paper we describe approaches to the ductilisation of two different classes of intermetallic alloys through alloying to introduce beneficial, second phase effects. The Ti2AlNb based intermetallics in the Ti-Al-Nb system can be ductilised by stabilising thebcc phase of titanium into the structure. The principles of microstructural and compositional optimization developed to achieve adequate plasticity, while retaining creep properties of these alloys, are described. An entirely different approach has been successful in imparting plasticity to intermetallics based on Fe3Al. The addition of carbon to form the Fe3AlC0.5 phase imparts ductility, while enhancing both tensile and creep strength

Counting reducible, powerful, and relatively irreducible multivariate polynomials over finite fields

We present counting methods for some special classes of multivariate polynomials over a finite field, namely the reducible ones, the s-powerful ones (divisible by the s-th power of a nonconstant polynomial), and the relatively irreducible ones (irreducible but reducible over an extension field). One approach employs generating functions, another one uses a combinatorial method. They yield exact formulas and approximations with relative errors that essentially decrease exponentially in the input size.Comment: to appear in SIAM Journal on Discrete Mathematic

Raman Scattering Study of Ba-doped C60 with t1g States

Raman spectra are reported for Ba doped fullerides, BaxC60(x=3,4,and 6). The lowest frequency Hg modes split into five components for Ba4C60 and Ba6C60 even at room temperature, allowing us a quantitative analysis based on the electron-phonon couping theory. For the superconducting Ba4C60, the density of states at the Fermi energy was derived as 7 eV-1, while the total value of electron-phonon coupling \lambda was found to be 1.0, which is comparable to that of K3C60. The tangential Ag(2) mode, which is known as a sensitive probe for the degree of charge transfer on C60 molecule, shows a remarkable shift depending on the Ba concentration, being roughly consistent with the full charge transfer from Ba to C60. An effect of hybridization between Ba and C60 \pi orbitals is also discussed.Comment: 15 pages, 6 figures submitted to Phys. Rev. B (December 1,1998

Zinc intake, status and indices of cognitive function in adults and children: a systematic review and meta-analysis

In developing countries, deficiencies of micronutrients are thought to have a major impact on child development; however, a consensus on the specific relationship between dietary zinc intake and cognitive function remains elusive. The aim of this systematic review was to examine the relationship between zinc intake, status and indices of cognitive function in children and adults. A systematic literature search was conducted using EMBASE, MEDLINE and Cochrane Library databases from inception to March 2014. Included studies were those that supplied zinc as supplements or measured dietary zinc intake. A meta-analysis of the extracted data was performed where sufficient data were available. Of all of the potentially relevant papers, 18 studies met the inclusion criteria, 12 of which were randomised controlled trials (RCTs; 11 in children and 1 in adults) and 6 were observational studies (2 in children and 4 in adults). Nine of the 18 studies reported a positive association between zinc intake or status with one or more measure of cognitive function. Meta-analysis of data from the adult’s studies was not possible because of limited number of studies. A meta-analysis of data from the six RCTs conducted in children revealed that there was no significant overall effect of zinc intake on any indices of cognitive function: intelligence, standard mean difference of <0.001 (95% confidence interval (CI) –0.12, 0.13) P=0.95; executive function, standard mean difference of 0.08 (95% CI, –0.06, 022) P=0.26; and motor skills standard mean difference of 0.11 (95% CI –0.17, 0.39) P=0.43. Heterogeneity in the study designs was a major limitation, hence only a small number (n=6) of studies could be included in the meta-analyses. Meta-analysis failed to show a significant effect of zinc supplementation on cognitive functioning in children though, taken as a whole, there were some small indicators of improvement on aspects of executive function and motor development following supplementation but high-quality RCTs are necessary to investigate this further

Effects of self-management, education and specific exercises, delivered by health professionals, in patients with osteoarthritis of the knee

<p>Abstract</p> <p>Background</p> <p>An education self-management program for people with osteoarthritis (OA) of the knee was designed to be delivered by health professionals, incorporating their knowledge and expertise. Improvement in quality of life, health status and pain in response to this program has previously been demonstrated in an uncontrolled pilot study. To more rigorously test the effectiveness of the program we will undertake a randomised controlled trial of people with OA of the knee offering specific self-administered exercises and education, in accordance with the principles of self-management.</p> <p>Aim: To determine whether an education self management program for subjects with Osteoarthritis (OA) of the knee (OAK program) implemented by health professionals in a primary health care setting can achieve and maintain clinically meaningful improvements compared standard medical management in a control group.</p> <p>Methods</p> <p>The effects of standard medical management will be compared with the effects of the OAK program in a single-blind randomized study.</p> <p><it>Participants: </it>146 male and female participants with established OA knee will be recruited. Volunteers with coexistent inflammatory joint disease or serious co-morbidities will be excluded.</p> <p><it>Interventions: </it>Participants will be randomized into either intervention or control groups (delayed start). The intervention group will complete the OA knee program and both groups will be followed for 6 months.</p> <p><it>Measurements: </it>Assessments will be at baseline, 8 weeks and 6 months. SF-36, WOMAC and VAS pain questionnaires will be completed. Isometric quadriceps and hamstring strength will be measured using a dynamometer; knee range of movement using a goniometer; and physical function will be determined by a modified timed up and go test. Data will be analysed using repeated measures ANOVA.</p> <p>Discussion</p> <p>While there is evidence to support the effectiveness of SM programs for people with hypertension, diabetes and asthma, the evidence available for treatment of arthritis remains equivocal. The aim of this study is to determine the effectiveness of a disease specific self-management program for people with OA knee.</p> <p>The study design includes all the important features of a clinical experimental study to minimize bias so the results of the study will provide a high level of evidence. People with OA of the knee have identified pain and problems with daily activities as the most important problems associated with their condition. The outcome measures selected specifically address these issues and have demonstrated validity and are responsive within the range of change expected in response to the intervention. Hence the results of the study will reflect their priorities.</p> <p>The results of the study will provide evidence to guide clinicians and funding bodies seeking to establish priorities regarding the provision of this disease specific program.</p> <p>Trial registration</p> <p>ACTR number: 12607000080426</p

Recommendations for defining preventable HIV-related mortality for public health monitoring in the era of Getting to Zero: an expert consensus

Getting to Zero is a commonly cited strategic aim to reduce mortality due to both HIV and avoidable deaths among people with HIV. However, no clear definitions are attached to these aims with regard to what constitutes HIV-related or preventable mortality, and their ambition is limited. This Position Paper presents consensus recommendations to define preventable HIV-related mortality for a pragmatic approach to public health monitoring by use of national HIV surveillance data. These recommendations were informed by a comprehensive literature review and agreed by 42 international experts, including clinicians, public health professionals, researchers, commissioners, and community representatives. By applying the recommendations to 2019 national HIV surveillance data from the UK, we show that 30% of deaths among people with HIV were HIV-related or possibly HIV-related, and at least 63% of these deaths were preventable or potentially preventable. The application of these recommendations by health authorities will ensure consistent monitoring of HIV elimination targets and allow for the identification of inequalities and areas for intervention

Short and medium-term effects of an education self-management program for individuals with osteoarthritis of the knee, designed and delivered by health professionals: A quality assurance study

<p>Abstract</p> <p>Background</p> <p>Self-management (SM) programs are effective for some chronic conditions, however the evidence for arthritis SM is inconclusive. The aim of this case series project was to determine whether a newly developed specific self-management program for people with osteoarthritis of the knee (OAK), implemented by health professionals could achieve and maintain clinically meaningful improvements.</p> <p>Methods</p> <p><it>Participants: </it>79 participants enrolled; mean age 66, with established osteoarthritis of the knee. People with coexisting inflammatory joint disease or serious co-morbidities were excluded.</p> <p><it>Intervention: </it>6-week disease (OA) and site (knee) specific self-management education program that included disease education, exercise advice, information on healthy lifestyle and relevant information within the constructs of self-management. This program was conducted in a community health care setting and was delivered by health professionals thereby utilising their knowledge and expertise.</p> <p><it>Measurements: </it>Pain, physical function and mental health scales were assessed at baseline, 8 weeks, 6 and 12 months using WOMAC and SF-36 questionnaires. Changes in pain during the 8-week intervention phase were monitored with VAS.</p> <p>Results</p> <p>Pain improved during the intervention phase: mean (95% CI) change 15 (8 to 22) mm. Improvements (0.3 to 0.5 standard deviation units) in indices of pain, mental health and physical functioning, assessed by SF-36 and WOMAC questionnaires were demonstrated from baseline to 12 months.</p> <p>Conclusion</p> <p>This disease and site-specific self-management education program improved health status of people with osteoarthritis of the knee in the short and medium term.</p