Modifications of Surface Properties of Beta Ti by Laser Surface Treatment

β -type Ti-alloy is a promising biomedical implant material as it has a low Young’s modulus but is also known to have inferior surface hardness. Various surface treatments can be applied to enhance the surface hardness. Physical vapour deposition (PVD) and chemical vapour deposition (CVD) are two examples of this but these techniques have limitations such as poor interfacial adhesion and high distortion. Laser surface treatment is a relatively new surface modification method to enhance the surface hardness but its application is still not accepted by the industry. The major problem of this process involves surface melting which results in higher surface roughness after the laser surface treatment. This paper will report the results achieved by a 100 W CW fiber laser for laser surface treatment without the surface being melted. Laser processing parameters were carefully selected so that the surface could be treated without surface melting and thus the surface finish of the component could be maintained. The surface and microstructural characteristics of the treated samples were examined using X-ray diffractometry (XRD), optical microscopy (OM), 3-D surface profile & contact angle measurements and nano-indentation test.

Pleiotropic analysis of cancer risk loci on esophageal adenocarcinoma risk

Background: Several cancer-associated loci identified from genome-wide association studies (GWAS) have been associated with risks of multiple cancer sites, suggesting pleiotropic effects. We investigated whether GWAS-identified risk variants for other common cancers are associated with risk of esophageal adenocarcinoma (EA) or its precursor, Barrett's esophagus. 

Methods: We examined the associations between risks of EA and Barrett's esophagus and 387 SNPs that have been associated with risks of other cancers, by using genotype imputation data on 2,163 control participants and 3,885 (1,501 EA and 2,384 Barrett's esophagus) case patients from the Barrett's and Esophageal Adenocarcinoma Genetic Susceptibility Study, and investigated effect modification by smoking history, body mass index (BMI), and reflux/heartburn. 

Results: After correcting for multiple testing, none of the tested 387 SNPs were statistically significantly associated with risk of EA or Barrett's esophagus. No evidence of effect modification by smoking, BMI, or reflux/heartburn was observed. 

Conclusions: Genetic risk variants for common cancers identified from GWAS appear not to be associated with risks of EA or Barrett's esophagus. 

Impact: To our knowledge, this is the first investigation of pleiotropic genetic associations with risks of EA and Barrett's esophagus.

Learning Bayesian Networks with Thousands of Variables

We present a method for learning Bayesian networks from data sets containing thousands of variables without the need for structure constraints. Our approach is made of two parts. The first is a novel algorithm that effectively explores the space of possible parent sets of a node. It guides the exploration towards the most promising parent sets on the basis of an approximated score function that is computed in constant time. The second part is an improvement of an existing ordering-based algorithm for structure optimization. The new algorithm provably achieves a higher score compared to its original formulation. Our novel approach consistently outperforms the state of the art on very large data sets.

Injurious tail biting in pigs: How can it be controlled in existing systems without tail docking?

Tail biting is a serious animal welfare and economic problem in pig production. Tail docking, which reduces but does not eliminate tail biting, remains widespread. However, in the EU tail docking may not be used routinely, and some 'alternative' forms of pig production and certain countries do not allow tail docking at all. Against this background, using a novel approach focusing on research where tail injuries were quantified, we review the measures that can be used to control tail biting in pigs without tail docking. Using this strict criterion, there was good evidence that manipulable substrates and feeder space affect damaging tail biting. Only epidemiological evidence was available for effects of temperature and season, and the effect of stocking density was unclear. Studies suggest that group size has little effect, and the effects of nutrition, disease and breed require further investigation. The review identifies a number of knowledge gaps and promising avenues for future research into prevention and mitigation. We illustrate the diversity of hypotheses concerning how different proposed risk factors might increase tail biting through their effect on each other or on the proposed underlying processes of tail biting. A quantitative comparison of the efficacy of different methods of provision of manipulable materials, and a review of current practices in countries and assurance schemes where tail docking is banned, both suggest that daily provision of small quantities of destructible, manipulable natural materials can be of considerable benefit. Further comparative research is needed into materials, such as ropes, which are compatible with slatted floors. Also, materials which double as fuel for anaerobic digesters could be utilised. As well as optimising housing and management to reduce risk, it is important to detect and treat tail biting as soon as it occurs. Early warning signs before the first bloody tails appear, such as pigs holding their tails tucked under, could in future be automatically detected using precision livestock farming methods enabling earlier reaction and prevention of tail damage. However, there is a lack of scientific studies on how best to respond to outbreaks: the effectiveness of, for example, removing biters and/or bitten pigs, increasing enrichment, or applying substances to tails should be investigated. Finally, some breeding companies are exploring options for reducing the genetic propensity to tail bite. If these various approaches to reduce tail biting are implemented we propose that the need for tail docking will be reduced. © 2014 The Animal Consortium.

The welfare implications of large litter size in the domestic pig I:Biologica factors

Increasing litter size has long been a goal of pig breeders and producers, and may have implications for pig (Sus scrofa domesticus) welfare. This paper reviews the scientific evidence on biological factors affecting sow and piglet welfare in relation to large litter size. It is concluded that, in a number of ways, large litter size is a risk factor for decreased animal welfare in pig production. Increased litter size is associated with increased piglet mortality, which is likely to be associated with significant negative animal welfare impacts. In surviving piglets, many of the causes of mortality can also occur in non-lethal forms that cause suffering. Intense teat competition may increase the likelihood that some piglets do not gain adequate access to milk, causing starvation in the short term and possibly long-term detriments to health. Also, increased litter size leads to more piglets with low birth weight which is associated with a variety of negative long-term effects. Finally, increased production pressure placed on sows bearing large litters may produce health and welfare concerns for the sow. However, possible biological approaches to mitigating health and welfare issues associated with large litters are being implemented. An important mitigation strategy is genetic selection encompassing traits that promote piglet survival, vitality and growth. Sow nutrition and the minimisation of stress during gestation could also contribute to improving outcomes in terms of piglet welfare. Awareness of the possible negative welfare consequences of large litter size in pigs should lead to further active measures being taken to mitigate the mentioned effects. © 2013 Universities Federation for Animal Welfare.

The welfare implications of large litter size in the domestic pig II:Management factors

Increasing litter size has long been a goal of pig (Sus scrofa domesticus) breeders and producers in many countries. Whilst this has economic and environmental benefits for the pig industry, there are also implications for pig welfare. Certain management interventions are used when litter size routinely exceeds the ability of individual sows to successfully rear all the piglets (ie viable piglets outnumber functional teats). Such interventions include: tooth reduction; split suckling; cross-fostering; use of nurse sow systems and early weaning, including split weaning; and use of artificial rearing systems. These practices raise welfare questions for both the piglets and sow and are described and discussed in this review. In addition, possible management approaches which might mitigate health and welfare issues associated with large litters are identified. These include early intervention to provide increased care for vulnerable neonates and improvements to farrowing accommodation to mitigate negative effects, particularly for nurse sows. An important concept is that management at all stages of the reproductive cycle, not simply in the farrowing accommodation, can impact on piglet outcomes. For example, poor stockhandling at earlier stages of the reproductive cycle can create fearful animals with increased likelihood of showing poor maternal behaviour. Benefits of good sow and litter management, including positive human-animal relationships, are discussed. Such practices apply to all production situations, not just those involving large litters. However, given that interventions for large litters involve increased handling of piglets and increased interaction with sows, there are likely to be even greater benefits for management of hyper-prolific herds. © 2013 Universities Federation for Animal Welfare.

Board invited review:The importance of the gestation period for welfare of calves: Maternal stressors and difficult births

The prenatal period is of critical importance in defining how individuals respond to their environment throughout life. Stress experienced by pregnant females has been shown to have detrimental effects on offspring biology in humans and a variety of other species. It also is becoming increasingly apparent that prenatal events can have important consequences for the behavior, health, and productivity of offspring in farmed species. Pregnant cattle may experience many potentially important stressors, for instance, relating to their social environment, housing system and physical environment, interactions with humans and husbandry procedures, and their state of health. We examined the available literature to provide a review of the implications of prenatal stress for offspring welfare in cattle. The long-term effects of dystocia on cattle offspring also are reviewed. To ensure a transparent and repeatable selection process, a systematic review approach was adopted. The research literature clearly demonstrates that prenatal stress and difficult births in beef and dairy cattle both have implications for offspring welfare and performance. Common husbandry practices, such as transport, were shown to influence offspring biology and the importance of environmental variables, including thermal stress and drought, also were highlighted. Maternal disease during pregnancy was shown to negatively impact offspring welfare. Moreover, dystocia-affected calves suffer increased mortality and morbidity, decreased transfer of passive immunity, and important physiological and behavioral changes. This review also identified considerable gaps in our knowledge and understanding of the effects of prenatal stress in cattle. © 2012 American Society of Animal Science. All rights reserved.

Farm animal welfare:Assessing risks attributable to the prenatal environment

An ever-expanding scientific literature highlights the impact of the prenatal environment on many areas of biology. Across all major farmed species, experimental studies have clearly shown that prenatal experiences can have a substantial impact on outcomes relevant to later health, welfare and productivity. In particular, stress or sub-optimal nutrition experienced by the mother during pregnancy has been shown to have wide-ranging and important effects on how her offspring cope with their social, physical and infectious environment. Variation in the conditions for development provided by the reproductive tract or egg, for instance by altered nutritional supply or hormonal exposure, may therefore explain a large degree of variation in many welfare- and productivity-relevant traits. The scientific literature suggests a number of management practices for pre-birth/hatch individuals that could compromise their later welfare. Such studies may have relevance for the welfare of animals under human care, depending on the extent to which real life conditions involve exposure to these practices. Overall, the findings highlight the importance of extending the focus on animal welfare to include the prenatal period, an aspect which until recently has been largely neglected. © 2012 Universities Federation for Animal Welfare The Old School.

Effects of sucrose on opioid gene expression in the rat brain.

Opioid peptide neurotransmitters stimulate feeding and are involved in mediating the rewarding aspects of feeding, as well as in energy regulation in the brain. The effects of sucrose diets on opioid peptide gene expression were measured in the arcuate nucleus (ARC) and the paraventricular nucleus (PVN) of the rat. Rats were fed a cornstarch-based diet or a low (16.7%), medium (33.4%), or high (50%) sucrose containing diet for 7 days. Analyses of the ARC and PVN demonstrated that sucrose in the diet had no effect on mRNA levels of opioid peptides. The lack of an opioid response in the ARC and PVN suggests that opioids in the ARC and PVN are involved in energy regulation rather than in mediating hedonic aspects of feeding.

Modifications of Surface Properties of Beta Ti by Laser Gas Diffusion Nitriding

Beta-type Ti-alloy is a promising biomedical implant material as it has a low Young’s modulus and is also known to have inferior surface hardness. Various surface treatments can be applied to enhance the surface hardness. Physical vapor deposition and chemical vapor deposition are two examples of this but these techniques have limitations such as poor interfacial adhesion and high distortion. Laser surface treatment is a relatively new surface modification method to enhance the surface hardness but its application is still not accepted by the industry. The major problem of this process involves surface melting which results in higher surface roughness after the laser surface treatment. This paper will report the results achieved by a 100 W continuous wave (CW) fiber laser for laser surface treatment without the surface being melted. Laser processing parameters were carefully selected so that the surface could be treated without surface melting and thus the surface finish of the component could be maintained. The surface and microstructural characteristics of the treated samples were examined using x-ray diffractometry, optical microscopy, three-dimensional surface profile and contact angle measurements, and nanoindentation test.

Laser Surface Treatment of Polyamide and NiTi Alloy and the Effects on Mesenchymal Stem Cell Response

Mesenchymal stem cells (MSCs) are known to play important roles in development, post-natal growth, repair, and regeneration of mesenchymal tissues. What is more, surface treatments are widely reported to affect the biomimetic nature of materials. This paper will detail, discuss and compare laser surface treatment of polyamide (Polyamide 6,6), using a 60 W CO2 laser, and NiTi alloy, using a 100 W fiber laser, and the effects of these treatments on mesenchymal stem cell response. The surface morphology and composition of the polyamide and NiTi alloy were studied by scanning electron microscopy (SEM) and X-ray photoemission spectroscopy (XPS), respectively. MSC cell morphology cell counting and viability measurements were done by employing a haemocytometer and MTT colorimetric assay. The success of enhanced adhesion and spreading of the MSCs on each of the laser surface treated samples, when compared to as-received samples, is evidenced in this work. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Towards the 2021 UK Census imputation strategy: Response mode as a matching variable in a donor-based approach?

Since July 2014, the Office for National Statistics has committed to a predominantly online 2021 UK Census. Item-level imputation will play an important role in adjusting the 2021 Census database. Research indicates that the internet may yield cleaner data than paper based capture and attract people with particular characteristics. Here, we provide preliminary results from research directed at understanding how we might manage these features in a 2021 UK Census imputation strategy. Our findings suggest that if using a donor-based imputation method, it may need to consider including response mode as a matching variable in the underlying imputation model.

Using the fluorescent properties of STO-609 as a tool to assist structure-function analyses of recombinant CaMKK2

Calcium/calmodulin-dependent kinase kinase 2 (CaMKK2) has been implicated in the regulation of metabolic activity in cancer and immune cells, and affects whole-body metabolism by regulating ghrelin-signalling in the hypothalamus. This has led to efforts to develop specific CaMKK2 inhibitors, and STO-609 is the standardly used CaMKK2 inhibitor to date. We have developed a novel fluorescence-based assay by exploiting the intrinsic fluorescence properties of STO-609. Here, we report an in vitro binding constant of KD ∼17 nM between STO-609 and purified CaMKK2 or CaMKK2:Calmodulin complex. Whereas high concentrations of ATP were able to displace STO-609 from the kinase, GTP was unable to achieve this confirming the specificity of this association. Recent structural studies on the kinase domain of CaMKK2 had implicated a number of amino acids involved in the binding of STO-609. Our fluorescent assay enabled us to confirm that Phe(267) is critically important for this association since mutation of this residue to a glycine abolished the binding of STO-609. An ATP replacement assay, as well as the mutation of the 'gatekeeper' amino acid Phe(267)Gly, confirmed the specificity of the assay and once more confirmed the strong binding of STO-609 to the kinase. In further characterising the purified kinase and kinase-calmodulin complex we identified a number of phosphorylation sites some of which corroborated previously reported CaMKK2 phosphorylation and some of which, particularly in the activation segment, were novel phosphorylation events. In conclusion, the intrinsic fluorescent properties of STO-609 provide a great opportunity to utilise this drug to label the ATP-binding pocket and probe the impact of mutations and other regulatory modifications and interactions on the pocket. It is however clear that the number of phosphorylation sites on CaMKK2 will pose a challenge in studying the impact of phosphorylation on the pocket unless the field can develop approaches to control the spectrum of modifications that occur during recombinant protein expression in E. coli.

Pro-internationalisation policies and outward foreign direct investment

This thesis addresses the impacts of public policies on outward foreign direct investment, seeking to contribute to a better understanding of the interplay between pro-internationalisation policies and firm behaviour. Home country measures associated with these policies are explored in terms of use and awareness, as determinants of foreign direct investment, as drivers of policy objectives, in terms of perceived importance and impact in different scenarios of internationalisation. Using a comprehensive database of 441 Portuguese firms, being those that had participated at least in one of the 11 types of public support between 1994 and 2009. The empirical papers presented here reveal a moderating effect of firm capabilities and internationalisation conditions on policy objectives. In fact, firms’ resources and capabilities frame the awareness and use of home country support measures, the existence of public policy determinants of foreign direct investment, the decision to carry out more aggressive modes of entry and the choice of more demanding environments, the impact of policy objectives, and the perceived importance of incentives. In practical terms, the findings of this thesis points that firms’ resources and capabilities are negatively associated with the use of public support, contrasting with awareness, which is found to increase with firms’ resources and capabilities. This insight sheds light on a potential problem of incentives allocation. Our results support the established theorizing about the co-evolution of government and firms' policies, home country measures being found as determinants of foreign direct investment. It is also shown that prointernationalization policies reinforce the firms’ resources and capabilities, which seems to have a positive impact on international growth. An evaluation of public policy, from the foreign direct investor's lens, supports the argument that firms involved in more demanding projects tend to attribute more importance to public supports. Behind the specific and concrete contributions identified in each of the empirical papers, as a whole this thesis makes methodological contributions by introducing the evaluation of impacts of public policies to the field of international business through the firm perspective; these contributions are achieved by taking the pro-internationalisation policies of a small open economy to better understand the impacts of public policies, and by shedding light on co-evolution between resource and institutional-based views.