Mechanical Property and Biocompatibility of PLLA Coated DCPD Composite Scaffolds

poster abstractIntroductions: Dicalcium phosphate dehydrate (DCPD) cements have been used for bone repair due to its excellent biocompatibility and resorability. However, DCPD cements are typically weak and brittleness. To address these limitations, the addition of sodium citrate as a regulator and polylactic acid (PLLA) as reinforcing agent has been proposed in this study. Objectives: 1) To develop composite PLLA/ DCPD scaffolds with enchanted toughness by PLLA coating. 2) To examine cell proliferation on the scaffolds. 3) To investigate the degradation behaviors of DCPD and PLLA/DCPD scaffolds. Materials and Methods: DCPD cements were synthesized with a 1:1 ratio of monocalcium phosphate monohydrate and -tricalcium phosphate with and without 100 mM sodium citrate in the mixing liquid. The specimens were prepared with powder to liquid ratio (P/L) of 1.00, 1.25 and 1.50. To fabricate the PLLA/DCPD composite scaffolds, DCPD scaffolds were coated with 5 % PLLA. The chemical and mechanical properties of DCPD scaffolds with and without PLLA coating after the in-vitro degradation (day 1, week 1, 4, and 6) were investigated by measuring their porosity, diametral tensile strength, and energy to fracture. In addition, cell adhesion and proliferation on these scaffolds were examined by scanning electron microscopy. Results: the addition of sodium citrate and the infiltration of PLLA significantly increased the mechanical properties of DCPD scaffolds (p < 0.05). The range of diametral tensile strength was 0.50-2.70 MPa and the range of energy to fracture was 0.80 to 9.90 N-mm. The most effective improvement of tensile strength and energy to fracture was achieved with P/L of 1.50. Moreover, incorporating PLLA to DCPD scaffolds slowed down the weight loss in the vitro degradation. Conclusion: a combination of template-casting and polymer impregnation methods can be applied to fabricate a cement/polymer biodegradable scaffold for bone tissue regeneration with significantly slow down degradation and excellent biocompatibility

Desire for experiential travel, avoidance of rituality and social esteem: An empirical study of consumer response to tourism innovation

AbstractThis study investigates tourist consumption responses toward tourism innovation. To measure tourist responses, this study posits three key consumption drivers, namely social esteem, desire for experiential travel, and avoidance against rituality of tourism settings (a subscale of need for uniqueness) and models consumers’ affective response within the context of tourism innovation. It involves 295 respondents in an empirical survey. The findings affirm the three drivers toward tourist consumption behavior. Avoidance of rituality reflects tourist preference toward tourism product and service innovation. Desire for experiential travel and the pursuit of social esteem signify tourism management and marketing innovation. Social esteem, need for status and creative choice have significant influence on tourists’ affective responses. Acquiring unique tourist products, desire for experiential travel and seeking social esteem are important motivations for tourist consumption. The implications of the study enrich the existing literature of consumer behavior and tourist consumption in response to tourism innovation

Fabrication of Poly-l-lactic Acid/Dicalcium Phosphate Dihydrate Composite Scaffolds with High Mechanical Strength-Implications for Bone Tissue Engineering

Scaffolds were fabricated from poly-l-lactic acid (PLLA)/dicalcium phosphate dihydrate (DCPD) composite by indirect casting. Sodium citrate and PLLA were used to improve the mechanical properties of the DCPD scaffolds. The resulting PLLA/DCPD composite scaffold had increased diametral tensile strength and fracture energy when compared to DCPD only scaffolds (1.05 vs. 2.70 MPa and 2.53 vs. 12.67 N-mm, respectively). Sodium citrate alone accelerated the degradation rate by 1.5 times independent of PLLA. Cytocompatibility of all samples were evaluated using proliferation and differentiation parameters of dog-bone marrow stromal cells (dog-BMSCs). The results showed that viable dog-BMSCs attached well on both DCPD and PLLA/DCPD composite surfaces. In both DCPD and PLLA/DCPD conditioned medium, dog-BMSCs proliferated well and expressed alkaline phosphatase (ALP) activity indicating cell differentiation. These findings indicate that incorporating both sodium citrate and PLLA could effectively improve mechanical strength and biocompatibility without increasing the degradation time of calcium phosphate cement scaffolds for bone tissue engineering purposes

Looking back to look forward: setting future research agenda for international business in textiles and clothing industry

Since its development by Tinbergen (1962), the gravity model of international trade has widely been applied to analyse the effect of various factors on trade relationships between countries. Past studies on trade gravity vary not only in the mix of model variables but also in how they have come into the analysis. This study reviews existing literature on bilateral trade with an aim to identify influential predictors such as changes of trade policy and national development strategy and highlight important yet understudied factors such as transport and logistics infrastructure, and sustainable development. To demonstrate the needs to examine these critical factors across industry sectors, the study presents the case of textiles and clothing (T&C) production and trade between China and its trading partners as an illustration. Through the literature review, it shows how the gravity model can be applied to address current issues in international trade arena such as the potential trade war between the US and China, China’s Belt and Road Initiative (BRI), and other important factors shaping global T&C trade. This study offers future research directions for analysis of global trade in the T&C industry and contributes to the wider literature of international business and trade

Effects of Bioactive Glass Scaffold and BMP-2 in Segmental Defects

poster abstractReconstruction of segmental defects in the load-bearing area has long been a challenge in orthopaedics. We have demonstrated the feasibility of a biodegradable load-bearing scaffold fabricated from poly(propylene fumarate)/tricalcium phosphate (PPF/TCP) loaded with bone morphogenetic protein-2 (BMP-2) to successfully induce healing in those defects. However, there is limited osteoconduction observed with the PPF/TCP scaffold itself. Furthermore, a recent review on BMP-2 revealed greater risks in radiculities, ectopic bone formation, osteolysis and poor global outcome in association with the use of BMP-2 for spinal fusion. The aims of this study were to evaluate the potential use of a more osteoconductive material 13-93 bioactive glass and the potential side effects of locally delivered BMP-2 on adjacent bones. 13-93 glass scaffolds were fabricated by indirect selective laser sintering and implanted into critical size defects created in rat right femurs with and without 10 micrograms of BMP-2. The X-ray and micro-CT results showed that bridging callus was found as soon as 3 weeks and progressed gradually in the BMP group while minimal bone formation was observed in the control group. As expected, stiffness, peak load and energy to break of the BMP group were all higher than the control group. Higher healing rates in the 13-93 group was found compared to the healing rate in PPF/TCP group evaluated in the past indicating a more osteoconductive nature of the 13-93 scaffolds. The scaffolds of both control and BMP groups were partially degraded after 15 weeks as seen in the histological images. For the effects of local BMP-2 delivery to adjacent bones, no statistical difference in the bone area, mineral content and mineral density was found between control and BMP groups. In conclusion, a 13-93 bioactive glass scaffold with local BMP-2 delivery has been demonstrated for its potential application in treating large bone defects

What are the opportunities for manufacturing in the “one belt one road” initiative? The case of Hong Kong’s textiles and clothing sector

The One Belt, One Road (hereafter OBOR) initiative is a development strategy launched by China in 2015. Its aim is to increase economic co-operation among countries along the China’s Silk Road Economic Belt and 21st Century Maritime Silk Road that connect Asia, Europe and Africa. As one of China’s important economic drivers, Hong Kong’s anticipated gains taking part in this initiative are substantial. This is particularly true for companies in the textiles and clothing (T&C) sectors, as the OBOR initiative offers investment opportunities in developing low-cost production bases in developing countries and promotes global trade. The main objective of this paper is twofold. First, it investigates how Hong Kong can strengthen its “superconnector” role, facilitating sustainable trade and development in the T&C industries among some OBOR countries. Specific measures are identified so that T&C companies in Hong Kong can establish and facilitate technological upgrades and transformation to potential production facilities in some developing countries under the OBOR initiative. This would contribute to the sustainable development of the T&C sectors in Hong Kong. Second, the study extends the gravity trade model to analyze the development of T&C trade patterns between Hong Kong and OBOR countries. Especially it covered some of the key factors not considered in previous studies, such as Logistics Performance Index (LPI), demographical factors, and those related to the business environment and policies. The analysis covers the impacts of country-specific, social, economic and supply chain factors on T&C trade. Based on the results, recommendations are provided to address how Hong Kong helps to facilitate trade and development of the T&C sectors under the OBOR initiative

Association of antipsychotic use with breast cancer:a systematic review and meta-analysis of observational studies with over 2 million individuals-CORRIGENDUM

AIMS: Despite reports of an elevated risk of breast cancer associated with antipsychotic use in women, existing evidence remains inconclusive. We aimed to examine existing observational data in the literature and determine this hypothesised association. METHODS: We searched Embase, PubMed and Web of Science™ databases on 27 January 2022 for articles reporting relevant cohort or case-control studies published since inception, supplemented with hand searches of the reference lists of the included articles. Quality of studies was assessed using the Newcastle-Ottawa Scale. We generated the pooled odds ratio (OR) and pooled hazard ratio (HR) using a random-effects model to quantify the association. This study was registered with PROSPERO (CRD42022307913). RESULTS: Nine observational studies, including five cohort and four case-control studies, were eventually included for review (N = 2 031 380) and seven for meta-analysis (N = 1 557 013). All included studies were rated as high-quality (seven to nine stars). Six studies reported a significant association of antipsychotic use with breast cancer, and a stronger association was reported when a greater extent of antipsychotic use, e.g. longer duration, was operationalised as the exposure. Pooled estimates of HRs extracted from cohort studies and ORs from case-control studies were 1.39 [95% confidence interval (CI) 1.11–1.73] and 1.37 (95% CI 0.90–2.09), suggesting a moderate association of antipsychotic use with breast cancer. CONCLUSIONS: Antipsychotic use is moderately associated with breast cancer, possibly mediated by prolactin-elevating properties of certain medications. This risk should be weighed against the potential treatment effects for a balanced prescription decision

The growing needs of genetic counselling—Feasibility in utilization of tele-genetic counselling in Asia and Hong Kong

The need for the expansion of genomic services has been at a record time high in the past decade. As technological advancement continues to strengthen the entire genetic and genomic pipeline and clinical operational workflow, the major challenge remains to be the speed of workforce development to meet service growth. In particular, the international expansion of genetic counselling (GC) services has been a topic of interest for the past few years. GC is an emerging profession in most of Asia, and in many countries the profession of GC often refers to physicians or front-line health workers with expertise in genetics to provide GC services rather than being a specific independent profession. As genetic and genomic services, especially pre-test and post-test GC, expand globally, the need to tackle the longstanding obstacles of GC personnel shortage and funding issues must not be overlooked. There is an urgent need internationally, and especially in Asia, where GC profession is comparatively less well-established, to seek alternative approaches to meet service demand. The present review examines the global development and feasibility of tele-genetics and tele-genetic counselling (TGC), and serves as the foundation to explore a possible roadmap in Hong Kong via the Hong Kong Genome Project

The photometric observation of the quasi-simultaneous mutual eclipse and occultation between Europa and Ganymede on 22 August 2021

Mutual events (MEs) are eclipses and occultations among planetary natural satellites. Most of the time, eclipses and occultations occur separately. However, the same satellite pair will exhibit an eclipse and an occultation quasi-simultaneously under particular orbital configurations. This kind of rare event is termed as a quasi-simultaneous mutual event (QSME). During the 2021 campaign of mutual events of jovian satellites, we observed a QSME between Europa and Ganymede. The present study aims to describe and study the event in detail. We observed the QSME with a CCD camera attached to a 300-mm telescope at the Hong Kong Space Museum Sai Kung iObservatory. We obtained the combined flux of Europa and Ganymede from aperture photometry. A geometric model was developed to explain the light curve observed. Our results are compared with theoretical predictions (O-C). We found that our simple geometric model can explain the QSME fairly accurately, and the QSME light curve is a superposition of the light curves of an eclipse and an occultation. Notably, the observed flux drops are within 2.6% of the theoretical predictions. The size of the event central time O-Cs ranges from -14.4 to 43.2 s. Both O-Cs of flux drop and timing are comparable to other studies adopting more complicated models. Given the event rarity, model simplicity and accuracy, we encourage more observations and analysis on QSMEs to improve Solar System ephemerides.Comment: 23 pages, 5 appendixes, 16 figures, 7 table