Constitutive models for fibre reinforced soil bricks

The authors gratefully acknowledge the research support fund provided by the Sudanese Ministry of Higher Education, School of Engineering, University of Khartoum and the School of Engineering, University of Aberdeen.Peer reviewedPostprin

Conditioned Medium from Bone Marrow Mesenchymal Stem Cells Restored Oxidative Stress-Related Impaired Osteogenic Differentiation

Oxidative stress from high levels of intracellular reactive oxygen species (ROS) has been linked to various bone diseases. Previous studies indicate that mesenchymal stem cells (MSC) secrete bioactive factors (conditioned medium (MSC-CM)) that have antioxidant effects. However, the antioxidant role of MSC-CM on osteogenesis has not been fully studied. We aimed to identify antioxidant proteins in MSC-CM using mass spectrometry-based proteomics and to explore their effects on osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSC) exposed to oxidative stress induced by hydrogen peroxide (H2O2). Our analysis revealed that MSC-CM is comprised of antioxidant proteins that are involved in several biological processes, including negative regulation of apoptosis and positive regulation of cell proliferation. Then, hBMSC exposed to H2O2 were treated with MSC-CM, and the effects on their osteogenic differentiation were evaluated. MSC-CM restored H2O2-induced damage to hBMSC by increasing the antioxidant enzyme-SOD production and the mRNA expression level of the anti-apoptotic BCL-2. A decrease in ROS production and cellular apoptosis was also shown. MSC-CM also modulated mRNA expression levels of osteogenesis-related genes, runt-related transcription factor 2, collagen type I, bone morphogenic protein 2, and osteopontin. Furthermore, collagen type I protein secretion, alkaline phosphatase activity, and in vitro mineralization were increased. These results indicate that MSC-CM contains several proteins with antioxidant and anti-apoptotic properties that restored the impaired hBMSC osteogenic differentiation associated with oxidative stress.publishedVersio

Understanding of how the properties of medical grade lactide based copolymer scaffolds influence adipose tissue regeneration: Sterilization and a systematic in vitro assessment

Aliphatic polyesters are the synthetic polymers most commonly used in the development of resorbable medical implants/devices. Various three-dimensional (3D) scaffolds have been fabricated from these polymers and used in adipose tissue engineering. However, their systematic evaluation altogether lacks, which makes it difficult to select a suitable degradable polymer to design 3D resorbable implants and/or devices able to effectively mimic the properties of adipose tissue. Additionally, the impact of sterilization methods on the medical devices, if any, must be taken into account. We evaluate and compare five different medical-grade resorbable polyesters with l-lactide content ranging from 50 to 100 mol% and exhibiting different physiochemical properties depending on the comonomer (d-lactide, ε-caprolactone, glycolide, and trimethylene carbonate). The salt-leaching technique was used to prepare 3D microporous scaffolds. A comprehensive assessment of physical, chemical, and mechanical properties of the scaffolds was carried out in PBS at 37 °C. The cell-material interactions and the ability of the scaffolds to promote adipogenesis of human adipose tissue-derived stem cells were assessed in vitro. The diverse physical and mechanical properties of the scaffolds, due to the different composition of the copolymers, influenced human adipose tissue-derived stem cells proliferation and differentiation. Scaffolds made from polymers which were above their glass transition temperature and with low degree of crystallinity showed better proliferation and adipogenic differentiation of stem cells. The effect of sterilization techniques (electron beam and ethylene oxide) on the polymer properties was also evaluated. Results showed that scaffolds sterilized with the ethylene oxide method better retained their physical and chemical properties. Overall, the presented research provides (i) a detailed understanding to select a degradable polymer that has relevant properties to augment adipose tissue regeneration and can be further used to fabricate medical devices/implants; (ii) directions to prefer a sterilization method that does not change polymer properties.publishedVersio

Contact osteogenesis by biodegradable 3D-printed poly(lactide-co-trimethylene carbonate)

Background To support bone regeneration, 3D-printed templates function as temporary guides. The preferred materials are synthetic polymers, due to their ease of processing and biological inertness. Poly(lactide-co-trimethylene carbonate) (PLATMC) has good biological compatibility and currently used in soft tissue regeneration. The aim of this study was to evaluate the osteoconductivity of 3D-printed PLATMC templates for bone tissue engineering, in comparison with the widely used 3D-printed polycaprolactone (PCL) templates. Methods The printability and physical properties of 3D-printed templates were assessed, including wettability, tensile properties and the degradation profile. Human bone marrow-derived mesenchymal stem cells (hBMSCs) were used to evaluate osteoconductivity and extracellular matrix secretion in vitro. In addition, 3D-printed templates were implanted in subcutaneous and calvarial bone defect models in rabbits. Results Compared to PCL, PLATMC exhibited greater wettability, strength, degradation, and promoted osteogenic differentiation of hBMSCs, with superior osteoconductivity. However, the higher ALP activity disclosed by PCL group at 7 and 21 days did not dictate better osteoconductivity. This was confirmed in vivo in the calvarial defect model, where PCL disclosed distant osteogenesis, while PLATMC disclosed greater areas of new bone and obvious contact osteogenesis on surface. Conclusions This study shows for the first time the contact osteogenesis formed on a degradable synthetic co-polymer. 3D-printed PLATMC templates disclosed unique contact osteogenesis and significant higher amount of new bone regeneration, thus could be used to advantage in bone tissue engineering.publishedVersio

Bone regeneration in rat calvarial defects using dissociated or spheroid mesenchymal stromal cells in scaffold-hydrogel constructs

Background Three-dimensional (3D) spheroid culture can promote the osteogenic differentiation of bone marrow mesenchymal stromal cells (BMSC). 3D printing offers the possibility to produce customized scaffolds for complex bone defects. The aim of this study was to compare the potential of human BMSC cultured as 2D monolayers or 3D spheroids encapsulated in constructs of 3D-printed poly-L-lactide-co-trimethylene carbonate scaffolds and modified human platelet lysate hydrogels (PLATMC-HPLG) for bone regeneration. Methods PLATMC-HPLG constructs with 2D or 3D BMSC were assessed for osteogenic differentiation based on gene expression and in vitro mineralization. Subsequently, PLATMC-HPLG constructs with 2D or 3D BMSC were implanted in rat calvarial defects for 12 weeks; cell-free constructs served as controls. Bone regeneration was assessed via in vivo computed tomography (CT), ex vivo micro-CT and histology. Results Osteogenic gene expression was significantly enhanced in 3D versus 2D BMSC prior to, but not after, encapsulation in PLATMC-HPLG constructs. A trend for greater in vitro mineralization was observed in constructs with 3D versus 2D BMSC (p > 0.05). In vivo CT revealed comparable bone formation after 4, 8 and 12 weeks in all groups. After 12 weeks, micro-CT revealed substantial regeneration in 2D BMSC (62.47 ± 19.46%), 3D BMSC (51.01 ± 24.43%) and cell-free PLATMC-HPLG constructs (43.20 ± 30.09%) (p > 0.05). A similar trend was observed in the histological analysis. Conclusion Despite a trend for superior in vitro mineralization, constructs with 3D and 2D BMSC performed similarly in vivo. Regardless of monolayer or spheroid cell culture, PLATMC-HPLG constructs represent promising scaffolds for bone tissue engineering applications.publishedVersio

AWARENESS AND USE OF NUTRITION INFORMATION ON FOOD PACKAGES AMONG CONSUMERS IN MASERU (LESOTHO)

ABSTRACT Food product labelling has become a popular policy tool, particularly with respect to the provision of nutrition and health information. Nutrition labelling is a valuable tool in learning how to apply nutrition information in a practical way. Nutrition information on food labels can help consumers to choose healthier food. For companies competing in the global food and beverage marketplace, understanding local consumer attitudes and purchase behaviour regarding healthy foods, nutrition, and labelling is critically important for success. This study attempts to evaluate the level of knowledge and use of nutrition information on food packages among consumers in Maseru, Lesotho. A structured questionnaire, covering aspects of knowledge and use of food labels and nutrition information, was used to collect information from two hundred and sixty consumers. The study also included open-ended questions on what consumers expected to be on the food label, what they understand by nutrition information, what its importance is, and if they think it should be included on the food package labels and why. The findings indicate that the main demographic features of the participants were: 67.3% female, 59.6% married, 55.9% completed primary, middle or high school, and 68.4% were poor. Majority (71.2%) of the participants claimed that they use a shopping list. Less than half of the participants (40.5%) indicated that nutrition information on food labels, rather than price, taste, appearance, habit, convenience, or brand name, was their main motivator to purchase foods. With regard to food label and nutrition information knowledge, a majority of the participants said they knew about them (59.6% for food label knowledge, and 69.2% for nutrition information knowledge). The same trend has been observed with respect to use of nutrition information on food labels when shopping, where 63.8% claimed that they utilise that knowledge when shopping. For the lowest income group, food price was the major determining factor of the types of foods they buy. A positive relationship between age of participants and nutrition information knowledge was observed. It was noted that as the level of education increased, the level of knowledge about food label increased. The level and use of nutrition knowledge when purchasing foods increased with age, education level and family income. Answers to the open-ended questions showed high degree of awareness about nutrition information on food labels, and why it is important to utilise that information

Nanoparticulate silica, new absorbents for PTE extraction from aqueous media and VOCs from indoor air

Strathclyde theses - ask staff. Thesis no. : T13168Mesoporous silica samples were synthesised and used as sorbents for VOCs. 4 VOCs were extracted from polluted air streams; toluene, ethylbenzene, cumene and dichlorobenzene. Extraction efficiencies were compared to a commercially available sorbent (Tenax TA) at different relative humidity (25 or 80 % RH) and at different flow rates (25, 50, 100, 150 or 200 cm3 min-1). Silica adsorbents showed efficient performance at low RH, whereas Tenax-TA performed better at high RH. A room temperature method of MCM-41 was developed producing a silica product which exhibited an ordered hexagonal mesostructure, large pore volume (up to 0.99 cm3/g), and unusually large pore size (up to 6.7 nm). Diethylenetriamine functionalised MCM-41 was used to extract Pb (II) ions from solution and showed significant adsorption capacity (up to 1000 μmol g-1). The sorbent was regenerated, and Pb (II) ions recovered, allowing reuse of the sorbent. Mercaptopropyl (MP) functionalised MCM-41 showed extremely efficient and selective adsorption for the removal of Hg (II) ions from water samples doped with a wide range of metal ions. Additionally a method was developed to remove Hg (II) ions from loaded MP-MCM-41. Finally, speciation and separation of Cr (VI) and Cr (III) ions from aqueous solutions was achieved using amino-propyl functionalised MCM-41. The maximum adsorption capacity at 111.1 mg g-1 was calculated according to the Langmuir isotherm model. Silica materials with different pore sizes were used to extract Cr (VI) ions from water and the results were examined using kinetics models. Different adsorption behaviours were observed; of which the most significant conclusion was that MWD-samples of MCM-41 had a 2 step adsorption process; the first related to the diffusion of ions through the liquid to the sorbent surface and the second being the diffusion of ions through the large functionalised pores which explains the increased adsorption performance of MWD-MCM-41.Mesoporous silica samples were synthesised and used as sorbents for VOCs. 4 VOCs were extracted from polluted air streams; toluene, ethylbenzene, cumene and dichlorobenzene. Extraction efficiencies were compared to a commercially available sorbent (Tenax TA) at different relative humidity (25 or 80 % RH) and at different flow rates (25, 50, 100, 150 or 200 cm3 min-1). Silica adsorbents showed efficient performance at low RH, whereas Tenax-TA performed better at high RH. A room temperature method of MCM-41 was developed producing a silica product which exhibited an ordered hexagonal mesostructure, large pore volume (up to 0.99 cm3/g), and unusually large pore size (up to 6.7 nm). Diethylenetriamine functionalised MCM-41 was used to extract Pb (II) ions from solution and showed significant adsorption capacity (up to 1000 μmol g-1). The sorbent was regenerated, and Pb (II) ions recovered, allowing reuse of the sorbent. Mercaptopropyl (MP) functionalised MCM-41 showed extremely efficient and selective adsorption for the removal of Hg (II) ions from water samples doped with a wide range of metal ions. Additionally a method was developed to remove Hg (II) ions from loaded MP-MCM-41. Finally, speciation and separation of Cr (VI) and Cr (III) ions from aqueous solutions was achieved using amino-propyl functionalised MCM-41. The maximum adsorption capacity at 111.1 mg g-1 was calculated according to the Langmuir isotherm model. Silica materials with different pore sizes were used to extract Cr (VI) ions from water and the results were examined using kinetics models. Different adsorption behaviours were observed; of which the most significant conclusion was that MWD-samples of MCM-41 had a 2 step adsorption process; the first related to the diffusion of ions through the liquid to the sorbent surface and the second being the diffusion of ions through the large functionalised pores which explains the increased adsorption performance of MWD-MCM-41

Extent types of and the factors related to malnutrition among children under three years of age in Botswana

Malnutrition affects physical growth, morbidity, mortality, cognitive development, reproduction, and physical work capacity, and it consequently impacts on human performance, health and survival. It is an underlying factor in many diseases for both children and adults, and is particularly prevalent in developing countries, where it affects one out of every 3 preschool-age children. A well-nourished child is one whose weight and height measurements compare very well with the standard normal distribution of heights and weights of healthy children of the same age and sex. Factors that contribute to malnutrition are many and varied. The objective of the present study is to evaluate the level of malnutrition and the impact of some socio-economic and demographic factors of households on the nutritional status of children under 3 years of age in Botswana. Factors included: the number of children under 3 years of age in the family, occupation of the parents, marital status, family income, parental education, maternal nutritional knowledge, residence location (urban or rural), gender, and breastfeeding practices. The study was a cross-sectional descriptive survey using a structured questionnaire and measurements of weight and height. Four hundred households and mothers of children under three, representing the 23 Health Regions of Botswana, participated in the study. Reference standards used were those of the National Center for Health Statistics (NCHS). EPI Info software (version 5) was used for data entry and analysis. The results show that the level of wasting, stunting, and underweight in children under three years of age was 5.5 %, 38.7 %, and 15.6 % respectively. Malnutrition was significantly (p < 0.01) higher among boys than among girls. Underweight was less prevalent among children whose parents worked in the agricultural sector than among children whose parents were involved in informal business. Children brought up by single parents suffered from underweight to a significantly (p < 0.01) higher level than children living with both parents. The prevalence of underweight decreased significantly (p < 0.01) as family income increased. The higher the level of the mother's education, the lower the level of child underweight observed. Breastfeeding was found to reduce the occurrence of underweight among children. The study findings imply that efforts for redressing child under nutrition issues in Botswana should focus on factors associated with development outcomes such as maternal income, maternal education, and the creation of employment or economic engagements that do not compromise important child care practices such as breastfeeding. Keywords: child malnutrition, socio-economic factors, breastfeeding, Botswana, pre-school children African Journal of Food, Agriculture, Nutrition and Development Vol. 6(1) 200

Selective extraction of mercury(II) from water samples using mercapto functionalised-MCM-41 and regeneration of the sorbent using microwave digestion

Silica sorbents, based on mesoporus crystalline material-41 (MCM-41), were functionalized using mercaptopropyl (MP) or diethylenetriamine (DETA) to extract mercury (II) ions from water. MP-MCM-41 was an extremely efficient and selective sorbent for the removal of mercury (II) from samples of distilled water doped with heavy metal ions, tap or river water. DETA-MCM-41 preferentially removed hard metal ions (chromium, manganese, lead and zinc) over soft metal ions such as mercury. During extraction, the influence of pH on adsorption capacity was examined; a maximum adsorption capacity of 1245 μmol g-1 was achieved for MP-MCM-41 even at pH values as low as 3. Significantly, a method has been developed, for the first time, to remove Hg (II) from loaded MP-MCM-41 allowing this analyte to be selectively removed from waters contaminated with a wide range of heavy metal ions. The regeneration method does not disrupt the chelating agent which remains on the surface of the silica permitting reuse of the sorbent in further extractions