Sustainable Supply Chain Management Drivers and Barriers in the Ethiopian Manufacturing Sec-tor

The prime essence of this paper is to identify the drivers of Sustainable Supply Chain Management (SSCM) and determine the barriers to its implementation in the Ethiopian manufacturing sector. Studies related to SSCM mainly from 2010 onwards are reviewed, analysed and discussed using exploratory and meta-synthesis analyses. The findings indicate that there is an absence of a clear connection between SSCM practices and performance among the manufacturing industries in Ethiopia. This creates a hindrance for manufacturing firms in Ethiopia seeking to implement SSCM

Development of chitosan based composite matrices for Bone tissue engineering

The thesis work deals with the development of chitosan (CS) based composite scaffold matrices with improved material and osteogenic differentiation property for bone tissue engineering. Pure CS and CS/ β-TCP composite scaffolds reinforced with micro and nano sized β-TCP with different CS:β-TCP ratios were successfully prepared by freeze gelation method and characterized for morphological, structural, mechanical, swelling, wettability and degradation. Pure CS and composite scaffolds possess interconnected open pore microstructure with desired pore size and porosity. The compressive strength of CS scaffold was remarkably increased by the incorporation of micro and nano sized β-TCP. However, the highest compressive strength of 2.67±0.21 MPa was achieved with CS/nano β-TCP composite scaffold at optimal CS:β-TCP ratio of 60:40. The scaffold also exhibited favourable biodegradation and improved bioactivity. The biocompatibility of the scaffold is confirmed by in-vitro cell culture study using human mesenchymal stem cells (hMSCs) seeded on the scaffold. Conjugation with fibrin is shown to be beneficial for improving cellular affinity of the scaffold which is evident by the enhanced cell attachment (FE-SEM), metabolic activity (MTT assay), proliferation (DNA quantification) and osteogenic differentiation (ALP), bio-mineralization, total calcium content and expression of osteogenic specific genes (semi quantitative RT-PCR) of seeded hMSCs. CS/nano β-TCP scaffold was cross-linked with genipin (GN) and sodium tri poly phosphate (TPP) with the aim of controlling rapid degradation rate of CS scaffold and improving mechanical strength. Thus the developed GN cross-linked CS/nano β-TCP composite scaffold has shown favourable degradation (8%) and higher compressive strength (2.78±0.11) than the scaffold cross-linked with TPP. CS/nano β-TCP/GN scaffold was further coated with fibrin thereby a significant improvement of cellular responses such as cell attachment, proliferation, metabolic activity and osteogenic differentiation was achieved. The enhanced osteogenic differentiation ability of the fibrin coated scaffold was further evident by Semi Quantitative RT-PCR study that has revealed up regulation in the expression of osteogenic specific genes like collagen 1 (COL1), osteocalcein (OC), bone sialo protein (BSP), osteonectin (ON), β-actin and ALP. In-vivo biocompatibility of the CS/nano β-TCP/GN/F composite scaffold was confirmed by animal testing using mice model. All together, the study has demonstrated that the developed CS composite scaffolds in particular CS/nano β-TCP/GN/F can be used as potential artificial ECM (extra cellular matrix) for various non-load bearing bone tissue engineering applications

Hybridizing Micro - B4C with Carbon nanotubes to Enhance the Mechanical Properties of Aluminium Matrix Composites

In present work, the effects of hybridizing micron sized B4C particles with multi walled carbon nanotubes on the microstructural and mechanical properties of Al - B4C composite were investigated. Microstructure reveals grain refinement ascribed to the presence of uniformly distributed micron sized B4C particles with multi walled carbon nanotubes. The Al - (B4C + MWCNT) hybrid composite indicates the alliance of mechanical properties such as hardness, tensile strength and ductility. The enhanced attribute of Al - (B4C + MWCNT) hybrid composite when compared to Al - B4C is the increased content and uniform distribution of MWCNTs. © Published under licence by IOP Publishing Ltd

Regulation of TNF-α and NF-κB activation through the JAK/STAT signaling pathway downstream of histamine 4 receptor in a rat model of LPS-induced joint inflammation.

Histamine 4 receptor (H4R) is a novel target for the pharmacological modulation of histamine-mediated immune signals during inflammatory diseases. The purpose of this study was to assess the effects of the H4R agonist 4-methylhistamine dihydrochloride (4-MeH) and antagonist JNJ7777120 (JNJ) in the inflamed rat knee. Animals were fasted for 18h before a single dose of 4-MeH or JNJ (30mg/kg) was administered intraperitoneally (i.p.), both followed by intra-articular (i.a.) injection of LPS 2h later. Blood and synovial fluid were collected after a short incubation period and TNF-α, NF-κB, and IkB-α levels were measured via flow cytometry. Additionally, we assessed the effects of H4R engagement on the expression of IL-1β, TNF-α, and NF-κB mRNAs and the protein levels of TNF-α, NF-κB, JAK-1, and STAT-3 in the inflamed knee tissue. These results revealed increased TNF-α and NF-κB expression and decreased IkB-α levels in both the LPS alone and 4-MeH treated groups in whole blood and synovial fluid. Further, IL-1β, TNF-α, and NF-κB mRNA levels were significantly increased and western blot analysis confirmed increased expression of TNF-α, NF-κB, JAK-1, and STAT-3 in both LPS and 4-MeH treatment groups. Furthermore, these increases were completely inhibited in the inflamed knee tissue of the JNJ-treated group. Thus, the inhibition of inflammatory mediators and signaling pathways by the H4R antagonist JNJ suggests the anti-arthritic importance of this molecule