DESIGN OF BIOMIMETICALLY INSPIRED HYDROXYAPATITE-GELATIN BASED COMPOSITE FOR BONE SCAFFOLD APPLICATION

Bone tissue engineering (BTE) requires a sturdy biomimetic scaffold for restoration of large bone defects. This dissertation describes the progress made in improving our previously developed Gemosil composite consisting of Hydroxyapatite-Gelatin (HAp-Gel) with silane cross-linker as a potential scaffold. Our initial goal was to further improve the mechanical strength of the composite. We first successfully doubled the mechanical strength of the composite through adding selected co-solvent during the sol-gel process. We further experimentally confirmed that the improvement of the mechanical strength is due to the improved morphology of both the silane network and the Gemosil composite. Unfortunately, the scaffold fabricated from this composite (even with the newly optimized processing condition) underwent rapid degradation in water, and rapidly lost its mechanical strength. To mitigate this degradation issue, we attempted to incorporate a cross-linkable polymer into the Gemosil composite, aiming to further increase mechanical strength of the Gemosil composite with an additional polymeric network (i.e., reinforcing network). Specifically, we synthesized a new biocompatible and biodegradable copolymer, poly(L-lactide-co-propargyl carbonate) with pendent catechol functional groups. These catechol functional groups served as “liaison” molecules to help to improve the interfacial adhesion between the polymer network and the various components of the Gemosil. We demonstrated that through incorporating this copolymer together with mussel-inspired dopamine into Gemosil system, the compressive strength of the scaffold could be improved by 20% under aqueous condition. Finally, despite the impressive adhesive and coating property of dopamine/polydopamine demonstrated by us and others, polydopamine (PDA) has its own limitations. For instance, PDA’s black color is not favored for clinical applications and its polymerization mechanism is still elusive. We synthesized a series of dopamine analogues with different alkyl chain lengths between the catechol and the amine. We found all of these new dopamine analogues were able to polymerize. Through studying the adhesive and coating ability of these new dopamine analogues, together with systems having catechol and selected alkyl amines (unbound to catechol), we showed that the covalent linkage between the catechol and the amine via an alkyl chain is not required to show the adhesive property; however, this covalent link is crucial to achieve the impressive coating property of dopamine and its analogs. Our findings offer new insights in designing mussel-inspired materials for future BTE application, and further mechanistic understanding of the polymerization of dopamine and these new dopamine analogues.Doctor of Philosoph

The Effects of Packaging on Customer Purchasing Decision. (Melcom Ghana Limited)

This study’s goal was to reveal the impact of produce packaging on customers' purchasing decisions in the municipality of Ho. Using Melcom as a case study, the study selected a total of 109 customers of about 150 employees, and on what benefits to convenience. When collecting data, respondents who were analyzed using SPSS using frequency evaluation and One-Way Chi-Square were provided with self-managed questionnaires to determine the number and percentage of respondents who consent to specific statements and to check the importance of those answers. The outcome indicated that the packaging affects product prices, which affects the customer's purchasing decision. The study also determined that labels and printed materials promote the company's products and these elements affect consumers' decisions to make before they buy a product. The results also showed how packaging contributes to the company's product. The results showed that good packaging leaves a positive image of goods with the consumers. Based on the results, we have advised that manufacturers also use innovative ways to make packaging more attractive and qualitative, as it affects customer purchasing decisions. It is also recommended that consumer products deliver with good packaging that leaves a positive picture in their minds, creating brand loyalty. Keywords: consumer, customer, packaging, Melcom, shopping, promotion, products, purchasing DOI: 10.7176/JMCR/65-02 Publication date: February 29th 202

Child population, economic development and regional inequality of education resources in China

There is great inequality of educational resources between different provinces in China due to unbalanced economic development. Despite continued redistribution of financial resources by the central government in favor of poorer provinces, educational inequality remains. In this paper, we argue that focusing on educational resources is far from sufficient. Poorer provinces do not only suffer from a lower level of educational resources, but they also have more children to educate, i.e. a greater need for education. Combining and analyzing the data in the Sixth National Population Census of China and the official statistics on education spending and resources, we found that provincial-level variations in the child population and the child dependency ratio have made access to educational resources even more unequal given the unequal financial capacity at the provincial level. Poorer provinces face a higher child dependency ratio and have lower economic development, and these two factors jointly lead to limited educational resources. Apart from a much higher level of redistribution in favor of less developed provinces, encouraging more balanced distribution of teachers and more broadly promoting economic equality are essential to reduce inequality in educational resources in China

The Effect of the Crosstalk between Photoperiod and Temperature on the Heading-Date in Rice

Photoperiod and temperature are two important environmental factors that influence the heading-date of rice. Although the influence of the photoperiod on heading has been extensively reported in rice, the molecular mechanism for the temperature control of heading remains unknown. This study reports an early heading mutant derived from tissue culture lines of rice and investigates the heading-date of wild type and mutant in different photoperiod and temperature treatments. The linkage analysis showed that the mutant phenotype cosegregated with the Hd1 locus. Sequencing analysis found that the mutant contained two insertions and several single-base substitutions that caused a dramatic reduction in Hd1mRNA levels compared with wild type. The expression patterns of Hd1 and Hd3a were also analyzed in different photoperiod and temperature conditions, revealing that Hd1 mRNA levels displayed similar expression patterns for different photoperiod and temperature treatments, with high expression levels at night and reduced levels in the daytime. In addition, Hd1 displayed a slightly higher expression level under long-day and low temperature conditions. Hd3a mRNA was present at a very low level under low temperature conditions regardless of the day-length. This result suggests that suppression of Hd3a expression is a principle cause of late heading under low temperature and long-day conditions

The role of temperature in forming sol–gel biocomposites containing polydopamine

The processing temperature has a big impact on the mechanical properties of HAp-Gemosil composites containing polydopamine

Strong Neel ordering and luminescence correlation in a two-dimensional antiferromagnet

Magneto-optical effect has been widely used in light modulation, optical sensing and information storage. Recently discovered two-dimensional (2D) van der Waals layered magnets are considered as promising platforms for investigating novel magneto-optical phenomena and devices, due to the long-range magnetic ordering down to atomically-thin thickness, rich species and tunable properties. However, majority 2D antiferromagnets suffer from low luminescence efficiency which hinders their magneto-optical investigations and applications. Here, we uncover strong light-magnetic ordering interactions in 2D antiferromagnetic MnPS3 utilizing a newly-emerged near-infrared photoluminescence (PL) mode far below its intrinsic bandgap. This ingap PL mode shows strong correlation with the Neel ordering and persists down to monolayer thickness. Combining the DFT, STEM and XPS, we illustrate the origin of the PL mode and its correlation with Neel ordering, which can be attributed to the oxygen ion-mediated states. Moreover, the PL strength can be further tuned and enhanced using ultraviolet-ozone treatment. Our studies offer an effective approach to investigate light-magnetic ordering interactions in 2D antiferromagnetic semiconductors

Ampullary cancers harbor ELF3 tumor suppressor gene mutations and exhibit frequent WNT dysregulation

The ampulla of Vater is a complex cellular environment from which adenocarcinomas arise to form a group of histopathologically heterogenous tumors. To evaluate the molecular features of these tumors, 98 ampullary adenocarcinomas were evaluated and compared to 44 distal bile duct and 18 duodenal adenocarcinomas. Genomic analyses revealed mutations in the WNT signaling pathway among half of the patients and in all three adenocarcinomas irrespective of their origin and histological morphology. These tumors were characterized by a high frequency of inactivating mutations of ELF3, a high rate of microsatellite instability, and common focal deletions and amplifications, suggesting common attributes in the molecular pathogenesis are at play in these tumors. The high frequency of WNT pathway activating mutation, coupled with small-molecule inhibitors of β-catenin in clinical trials, suggests future treatment decisions for these patients may be guided by genomic analysis

Increased CDC20 expression is associated with pancreatic ductal adenocarcinoma differentiation and progression

<p>Abstract</p> <p>Purpose</p> <p>Cell division cycle 20 (CDC20) homolog is an anaphase-promoting complex activator that is essential for cell division, but whether its expression in pancreatic ductal adenocarcinoma (PDAC) is significant is unknown. In this retrospective study, we determined whether aberrant CDC20 expression can be used as a biomarker in pancreatic ductal adenocarcinoma (PDAC) tumorigenesis and whether its expression reflects clinical progression.</p> <p>Experimental design</p> <p>We compared CDC20 expression levels in normal, cancerous, and inflamed pancreatic tissues from stage II PDAC patients with clinical outcomes and determined CDC20 levels in seven PDAC cell lines. CDC20 was identified using a cDNA microarray database containing gene expression profiles for PDAC tissues and cell lines and chronic pancreatitis and normal pancreas tissues. Its expression was confirmed by real-time quantitative reverse-transcriptase-polymerase chain reaction (qRT-PCR). An immunohistochemical analysis of tissue microarrays from resected PDAC tumors and paired benign pancreatic tissues was done and CDC20 levels were correlated with clinical outcome.</p> <p>Results</p> <p>Fifty-six patients were included in this study. A microarray analysis revealed 5-fold higher CDC20 expression in PDAC tissue than in chronic pancreatitis tissue. A qRT-PCR analysis confirmed a mean 20-fold higher CDC20 level in PDAC tissue than in normal pancreas and pancreatitis tissue. RNA and protein CDC20 expression was detected in several PDAC cell lines. An immunohistochemical analysis revealed higher CDC20 protein expression levels in PDAC tissue than in normal pancreas tissue, and high CDC20 expression was associated with poor differentiation (<it>P </it>= 0.020) and a significantly lower 5-year recurrence-free survival rate (<it>P </it>= 0.039); we also found a trend toward a shorter overall survival duration.</p> <p>Conclusions</p> <p>Aberrant CDC20 expression may play an important role in PDAC tumorigenesis and progression and may thus be useful as a marker of disease progression and prognosis and as a therapeutic target.</p