No abstract

Compared with stainless steel and Co-Cr-based alloys, Ti and its alloys are widely used as biomedical implants due to many fascinating properties, such as superior mechanical properties, strong corrosion resistance, and excellent biocompatibility. After briefly introducing several most commonly used biomedical materials, this article reviews the recent development in Ti alloys and their biomedical applications, especially the low-modulus β-type Ti alloys and their design methods. This review also systemically investigates the recently attractive progress in preparation of biomedical Ti alloys, including additive manufacturing, porous powder metallurgy, and severe plastic deformation, applied in the manufacturing and the influenced microstructures and properties. Nevertheless, there are still some problems with the long-term performance of Ti alloys, and therefore several surface modification methods are reviewed to further improve their biological activity, wear resistance, and corrosion resistance. Finally, the biocompatibility of Ti and its alloys is concluded. Summarizing the findings from literature, future prediction is also conducted. Darmstadt. His current research interest is focusing on the metal additive manufacturing (e.g. selective laser melting, electron beam melting), titanium alloys and composites, and processing-microstructure-properties in high-performance materials.

Carbon-carbon bond-forming reductive elimination from elusive organocopper(III) complexes has been considered the key step in many copper-catalyzed and organocuprate reactions. However, organocopper(III) complexes with well-defined structures that can undergo reductive elimination are extremely rare, especially for the formation of Csp 3-Csp 3 bonds. We report herein a general method for the synthesis of a series [alkyl-Cu III-(CF 3) 3 ]complexes, the structures of which have been unequivocally characterized by NMR, mass spectrometry and X-ray crystal diffraction. At elevated temperature, these complexes undergo reductive elimination following first-order kinetics, forming alky-CF 3 products with good yields (up to 91%). Both Kinetic studies and DFT calculations indicate that the reductive elimination to form Csp 3-CF 3 bonds proceeds through a concerted transition state, with a ΔH ‡ =20 kcal/mol barrier.

Thanks to a considerable number of fascinating properties, titanium (Ti) and Ti alloys play important roles in a variety of industrial sectors. However, Ti and Ti alloys could not satisfy all industrial requirements; the degradation of Ti and Ti alloys always commences on their surfaces in service, which declines the performances of Ti workpieces. Therefore, with aim to further improve their mechanical, corrosion and biological properties, surface modification is often required for Ti and Ti alloys. This article reviews the technologies and recent developments of surface-modification methods with respect to Ti and Ti alloys, including mechanical, physical, chemical, and biochemical technologies. Conventional methods have limited improvement in the properties and/or restriction on the geometry of workpieces. Therefore, many advanced surfacemodification technologies have emerged in recent decades. New methods make Ti and Ti alloys have better performance and extended applications. With requirement of high surface properties in future. Understanding the mechanism in various surface-modification methods, combining the advantages of current technologies and developing new coating materials with high performance are required urgently. As such, incorporation of different surface-modification technologies with high-performance modified layers may be the mainstream of surface modifications for Ti and Ti alloys. . His current research interests focus on the metal additive manufacturing (e.g., selective laser melting, electron beam melting), titanium alloys and composites, and processing-microstructureproperties in high-performance materials.

Skeletal muscle mass was significantly associated with handgrip strength along with aging, but the association of skeletal muscle mass and walking speed was less significant. In sarcopenia diagnosis among Asian populations, ASM/ht(2) should be the most suitable index for skeletal muscle mass measurements, and physical performance should be measured universally beyond measurements of skeletal muscle mass.

A decline in physical and/or cognitive function is a common feature of aging, and frailty has been shown to be associated with cognitive impairment and dementia. This study aimed to evaluate the association between dynapenia, sarcopenia, and cognitive impairment among community-dwelling older people in Taiwan. Data from the I-Lan Longitudinal Aging Study (ILAS) were retrieved for study. Global cognitive function was assessed by Mini-Mental State Examination (MMSE), whereas the Chinese Version Verbal Learning Test, Boston Naming Test, Verbal Fluency Test, Taylor Complex Figure Test, Digits Backward Test, and Clock Drawing Test were used to assess different domains of cognitive function. Association between sarcopenia and global cognitive function as well as all different dimensions of cognitive function were evaluated. Data from 731 elderly participants (mean age 73.4 ± 5.4 years, 53.8% males) were used for study analysis. The overall prevalence of sarcopenia was 6.8%, which was significantly higher in men (9.3% versus 4.1%, p < 0.05). The mean MMSE score was 23.4 ± 4.4 for all participants, and 10.3% of the study participants were cognitively impaired. Sarcopenia was not significantly associated with global cognitive function (odds ratio [OR] = 1.55, p = 0.317), but global cognitive impairment was significantly associated with low physical performance (OR = 2.31, p = 0.003) and low muscle strength (OR = 2.59, p = 0.011). Nonetheless, sarcopenia was significantly associated with impairment in the verbal fluency test (OR = 3.96, p = 0.006) after adjustment for potential confounders. Dynapenia was significantly associated with cognitive impairment in multiple dimensions and global cognitive function, but sarcopenia was only associated with an impaired verbal fluency test. Reduced muscle strength and/or physical performance related to non-muscle etiology were strongly associated with cognitive impairment. More longitudinal studies are needed.

β-type titanium (Ti) alloys have attracted a lot of attention as novel biomedical materials in the past decades due to their low elastic moduli and good biocompatibility. This article provides a broad and extensive review of β-type Ti alloys in terms of alloy design, preparation methods, mechanical properties, corrosion behavior, and biocompatibility. After briefly introducing the development of Ti and Ti alloys for biomedical applications, this article reviews the design of β-type Ti alloys from the perspective of the molybdenum equivalency (Moeq) method and DV-Xα molecular orbital method. Based on these methods, a considerable number of β-type Ti alloys are developed. Although β-type Ti alloys have lower elastic moduli compared with other types of Ti alloys, they still possess higher elastic moduli than human bones. Therefore, porous β-type Ti alloys with declined elastic modulus have been developed by some preparation methods, such as powder metallurgy, additive manufacture and so on. As reviewed, β-type Ti alloys have comparable or even better mechanical properties, corrosion behavior, and biocompatibility compared with other types of Ti alloys. Hence, β-type Ti alloys are the more suitable materials used as implant materials. However, there are still some problems with β-type Ti alloys, such as biological inertness. As such, summarizing the findings from the current literature, suggestions forβ-type Ti alloys with bioactive coatings are proposed for the future development.

BackgroundHerpes zoster (HZ) is a prevalent viral disease that inflicts substantial morbidity and associated healthcare and socioeconomic burdens. Current treatments are not fully effective, especially among the most vulnerable patients. Although widely recommended, vaccination against HZ is not routine; barriers in Asia-Pacific include long-standing neglect of adult immunisation and sparse local data. To address knowledge gaps, raise awareness, and disseminate best practice, we reviewed recent data and guidelines on HZ from the Asia-Pacific region.MethodsWe searched PubMed, Scopus, and World Health Organization databases for articles about HZ published from 1994 to 2014 by authors from Australia, China, Hong Kong, India, Indonesia, Japan, Korea, Malaysia, New Zealand, the Philippines, Singapore, Taiwan, Thailand, and Vietnam. We selected articles about epidemiology, burden, complications, comorbidities, management, prevention, and recommendations/guidelines. Internet searches retrieved additional HZ immunisation guidelines.ResultsFrom 4007 retrieved articles, we screened-out 1501 duplicates and excluded 1264 extraneous articles, leaving 1242 unique articles. We found guidelines on adult immunisation from Australia, India, Indonesia, Malaysia, New Zealand, the Philippines, South Korea, and Thailand.HZ epidemiology in Asia-Pacific is similar to elsewhere; incidence rises with age and peaks at around 70 years – lifetime risk is approximately one-third. Average incidence of 3–10/1000 person-years is rising at around 5% per year. The principal risk factors are immunosenescence and immunosuppression. HZ almost always causes pain, and post-herpetic neuralgia is its most common complication. Half or more of hospitalised HZ patients have post-herpetic neuralgia, secondary infections, or inflammatory sequelae that are occasionally fatal. These disease burdens severely diminish patients’ quality of life and incur heavy healthcare utilisation.ConclusionsSeveral countries have abundant data on HZ, but others, especially in South-East Asia, very few. However, Asia-Pacific countries generally lack data on HZ vaccine safety, efficacy and cost-effectiveness. Physicians treating HZ and its complications in Asia-Pacific face familiar challenges but, with a vast aged population, Asia bears a unique and growing burden of disease. Given the strong rationale for prevention, most adult immunisation guidelines include HZ vaccine, yet it remains underused. We urge all stakeholders to give higher priority to adult immunisation in general and HZ in particular.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-017-2198-y) contains supplementary material, which is available to authorized users.