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This paper examines the extent to which the economic gains derived from gum and resin commercialization impact rural livelihood improvement under different resource management regimes in the drylands of Ethiopia and Sudan. Primary data were collected through semi-structured interviews with 240 randomly selected small-scale producers in four regions with gradients of resource management regimes. The survey was supplemented by secondary data, group discussions and key informant interviews. In the four regions, gum and resin income contributes to 14%–23% of the small-scale producers' household income. Absolute income was positively correlated with resource management regime and commercialization level. It was higher from cultivated resources on private lands, followed by regulated access to wild resources. In open-access resources, the producers' income was the lowest, although accessed by the poor and women. However, dependence on gum and resin was higher in open-access resource areas. Households' socioeconomic characteristics, resource access, production and marketing variables determining income from gum and resin were identified and their variation across the cases is discussed. Overall, gum and resin commercialization in the study areas play a potential poverty alleviation role as a source of regular income, a safety net, and a means of helping producers move out of poverty. [ABSTRACT FROM AUTHOR]

Color characteristics of the shades for different filler type resin composites were compared in the reflectance and transmittance modes, and specular component included (SCI) and specular component excluded (SCE) geometries for reflectance mode. Resin composites and shades used in this study were submicron filled Estelite Σ (Σ: Inc, A2, A3, B3, C2, OA2, OA3) and nanofilled Filtek™ Supreme XT (XT: Clear, A2E, A2B, A3B, C2B, A2D, A3D). Resin disks of 2 mm in thickness and final polish with 2,400-grit silicon carbide paper were kept in 100% humidity. One week after curing, color of the resin disks were measured with a spectrophotometer. Both for Σ and XT, reflectance of each of all shades measured with SCI were significantly higher than those with SCE. Compared to the values with SCI and SCE, the L* with SCI were significantly higher for all shades of Σ and XT, however, a* and b* were depended with brands and shades. Different filler type resin composites showed different color characteristics, reflectance, transmittance and L*a*b* distribution. In some shades, color difference between the measurement with SCI and SCE was visually perceptible level. It would be concluded that the color of resin composite measured with the SCI and SCE geometries differed. [ABSTRACT FROM AUTHOR]

Abstract: Polymeric systems gained great interest in the last decades as specialties in the field of drug delivery, being very attractive for their peculiar physico-chemical characteristics. In this paper we report the characterization of a chemical network based on guar gum (GG) cross-linked with glutaraldehyde (Ga). The system was studied at three different temperatures, 7, 25 and 37°C and at different ageing times in order to evaluate the influence of these two parameters on its stability. The experiments were carried out with a Texture Analyzer thus hardness, cohesion and Young modulus of the hydrogel were evaluated in the different conditions. Furthermore, relaxation experiments were performed and their interpretation, according to the Maxwell generalized model, allowed to describe the mechanical behaviour in terms of materials viscoelasticity theory. The kinetics of the chemical cross-linking was followed at 37°C by means of rheological measurements, i.e. recording the mechanical spectra of the gelling system. The storage and loss moduli followed a power law, expression of the mechanical and structural self-similarity which evolves during the cross-linking reaction. The critical exponent at the gel point was evaluated, together with the critical time corresponding to the infinity connectivity of the system and the phase angle between stress and strain. Furthermore, also the fractal dimension was evaluated assuming a complete screening of the excluded volume of the chains at the critical point. Information about the release behaviour of the hydrogel, used as a matrix for modified drug delivery of model molecules with different steric hindrance, is also given. [Copyright &y& Elsevier]

Additive manufacturing (AM) technologies provide more freedom to functional part design in various industries. One of the unique capabilities of AM is that multi-material parts can be produced with material compositional and geometric complexity. Multi-material parts have the advantage of achieving multiple performance requirements. In the research, we propose a framework for designing multi-material parts using AM processes. The proposed framework is composed of four interacting modules, including design requirement identification, primary material selection, AM process selection, material composition, and part geometry determination. Rules and guidelines for AM are integrated into the proposed framework with AM processes’ capabilities and constraints compiled in databases. We also introduce databases to assist in decision-making and ensure manufacturability of the designed multi-material part in various product design phases. The proposed framework is applied to a case study involving a conceptual design of a multi-material battery pack cooling plate. [ABSTRACT FROM AUTHOR]

This in vitro study evaluated the effect of light curing unit (LCU) type, mouthwashes, and soft drink on chemical degradation of a nanofilled resin composite. Samples (80) were divided into eight groups: halogen LCU, HS—saliva (control); HPT—Pepsi Twist®; HLC—Listerine®; HCP—Colgate Plax®; LED LCU, LS—saliva (control); LPT—Pepsi Twist®; LLC—Listerine®; LCP—Colgate Plax®. The degree of conversion analysis and the measure of the peak area at 2,930 cm−1 (organic matrix) of resin composite were done by Fourier-transform Raman spectroscopy (baseline, after 7 and 14 days). The data were subjected to multifactor analysis of variance (ANOVA) at a 95% confidence followed by Tukey's HSD post-hoc test. The DC ranged from 58.0% (Halogen) to 59.3% (LED) without significance. Differences in the peak area between LCUs were found after 7 days of storage in S and PT. A marked increase in the peak intensity of HLC and LLC groups was found. The soft-start light-activation may influence the chemical degradation of organic matrix in resin composite. Ethanol contained in Listerine® Cool Mint mouthwash had the most significant degradation effect. Raman spectroscopy is shown to be a useful tool to investigate resin composite degradation. [ABSTRACT FROM AUTHOR]