Reduction of Escherichia coli O157:H7 viability on leafy green vegetables by treatment with a bacteriophage mixture and trans-cinnamaldehyde

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 has been recognized as a major foodborne pathogen responsible for frequent gastroenteritis outbreaks. Phages and essential oils can be used as a natural antimicrobial method to reduce bacterial pathogens from the food supply. The objective of this study was to determine the effect of a bacteriophage cocktail, BEC8, alone and in combination with the essential oil trans-cinnameldehyde (TC) on the viability of a mixture of EHEC O157:H7 strains applied on whole baby romaine lettuce and baby spinach leaves. The EHEC O157:H7 strains used were Nal^R mutants of EK27, ATCC 43895, and 472. Exponentially growing cells from tryptic soy (TS) broth cultures were spot inoculated on leaves and dried. EHEC cells were placed at low, medium, and high inoculum levels (10⁴, 10⁵, and 10⁶ CFU/mL, respectively). Appropriate controls, BEC8 (approx. 10⁶ PFU/leaf), and TC (0.5% v/v) were applied on treated leaves. The leaves were incubated at 4, 8, 23, and 37 °C in Petri dishes with moistened filter papers. EHEC survival was determined using standard plate count on nalidixic acid (50 μg/mL) Sorbitol MacConkey agar. No survivors were detected when both leaves were treated with BEC8 or TC individually at low inoculum levels after 24 h at 23 and 37 °C. When the EHEC inoculum size increased and/or incubation temperature decreased, the efficacy of BEC8 and TC decreased. However, when the two treatments were combined, no survivors were detected after 10 min at all temperatures and inoculum levels on both leafy greens. These results indicated that the BEC8/TC combination was highly effective against EHEC on both leafy greens. This combination could potentially be used as an antimicrobial to inactivate EHEC O157:H7 and reduce their incidence in the food chain.     

Performance evaluation of silty sand reinforced with fibres

Triaxial compression tests were conducted to evaluate the response of randomly distributed fibre on the strength of reinforced silty sand. In this study, oil palm empty fruit bunch (OPEFB) fibre was mixed with silty sand soil to investigate the increase of shear strength during triaxial compression. The specimens were tested under drained and undrained conditions with 0.25% and 0.5% content of OPEFB fibres of different lengths (i.e. 15 mm, 30 mm and 45 mm). In addition, OPEFB fibres coated with acrylic butadiene styrene thermoplastic were tested to determine the effect of coating on reinforcement. Inclusion of randomly distributed discrete fibres significantly improved the shear strength of silty sand. Coated OPEFB fibres increased the shear strength of silty sand much more compared to uncoated fibres. Coating fibres increases interface friction between fibre and soil particles by increasing the surface area. Reinforced silty sand containing 0.5% coated fibres of 30 mm length exhibited approximately 25% increase in friction angle and 35% in cohesion under undrained loading conditions compared to those of unreinforced silty sand. The results indicate that the shear strength parameters of the soil-fibre mixture (i.e. Φ′ and c′) can be improved significantly.     

Performance of oil palm empty fruit bunch fibres coated with acrylonitrile butadiene styrene

Natural fibres are suitable for reinforcement of soils due to their availability, low cost and environment-friendly nature. Oil palm empty fruit bunches (OPEFB), solid waste produced during refinement of oil from oil palm fruit, provide fibres which have been used as reinforcement material for soil improvements. To protect the fibres from biodegrading in reinforced soil, OPEFB fibre is coated with non-biodegradable material. The effect of coating OPEFB fibres with acrylonitrile butadiene styrene (ABS) was evaluated. Morphological characterization, mechanical and physical properties of the coated fibres exhibited improved fibre performance. The ABS treatment protected fibres from water absorption and decreased the biodegradation potential of the fibres in contact with soil. The tensile strength and elasticity moduli of the OPEFB fibres were also improved with the coating. Coating fibres increases interface friction between fibre and soil particles due to increased surface area. The results were shown that the shear strength parameters of the fibre-reinforced soils can be improved significantly.     

Reduction of Escherichia coli O157:H7 viability on hard surfaces by treatment with a bacteriophage mixture

This study determined the effect of a previously characterized phage mixture, referred as BEC8 on enterohemorrhagic Escherichia coli (EHEC) O157:H7 strains applied on materials typically used in food processing surfaces. Sterile stainless steel chips (SSC), ceramic tile chips (CTC), and high density polyethylene chips (HDPEC) were used. Cultures of EHEC O157:H7 strains EK27, ATCC 43895, and 472 were combined, spot inoculated on surfaces, and dried. Chips were inoculated with 10⁶, 10⁵, and 10⁴CFU/chip, to obtain 1, 10 and 100 multiplicity of infection (MOI) values, respectively. Controls and BEC8 (approx. 10⁶ PFU/chip) were applied on inoculated surfaces and incubated at 4, 12, 23, and 37 °C. EHEC survival was determined using standard plate count on tryptic soy agar. At 37 °C and 12 °C on SSC, no survivors were detected (detection limit 10 CFU/chip) after BEC8 treatment at MOI of 100 after 10 min and at 23 °C after 1 h on SSC. A similar result was obtained on CTC at 37 °C after 10 min, and after 1 h at 23 °C. These results indicated that the phage cocktail was effective within an hour against low levels of the EHEC mixture at above room temperature on all 3 hard surfaces.     

Lycopene-rich fractions derived from pink guava by-product and their potential activity towards hydrogen peroxide-induced cellular and DNA damage

Effects of solvent and supercritical carbon dioxide (SC-CO₂) extraction on antioxidant and cytotoxic activities of lycopene-rich fractions of decanted pink guava by-product (decanter) were determined with lycopene-equivalent antioxidant capacity, β-carotene bleaching and MTT (3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide) assays. Extraction with SC-CO₂ gave a higher yield than solvent extraction (3.15 vs. 0.68 mg/100 g dried decanter, corresponding to 42.99 and 33.63 mg of lycopene). No cytotoxicity was found in Chang liver cells supplemented with either extracts (6.25–200 μg/ml). Solvent extract at 25 μg/ml (2.32 μM lycopene) and SC-CO₂ extract at 200 μg/ml (5.09 μM lycopene) had protective effect against hydrogen peroxide-induced cytotoxicity. However, only high concentrations of solvent extract (200 μg/ml; lycopene = 18.65 μM) or lycopene standard (10 μM) protected cells against DNA damage. Supercritical fluid extraction demonstrated a higher yield in lycopene-rich fraction from decanter. These fractions have the potential to be developed as a functional ingredient to prevent oxidative stress and other related diseases.     

Analysis of deposition mechanism during ultrafiltration of glycerin-rich solutions

Clarification of glycerin-rich solution is one of the potential applications of membrane within the oleochemical industry. However, one of the barriers in successfully utilizing the use of membranes such as ultrafiltration (UF) has been due to the fouling. In this work, flux decline during ultrafiltration of the glycerin-rich solutions was studied by using commercialized polymeric polyethersulphone (PES) membrane. Influence of fatty acids as foulants model (palmitic acid, stearic acid and oleic acid), pH of feed solution (3-10) and molecular weight cut-off (5 kDa, 20 kDa and 25 kDa) were analyzed. All the experiments were performed at constant pressure (2 bar) and temperature (40 °C). The Hermia's model was used to analyze the fouling mechanism during the flux decline which involve cake layer model due to adsorption of solute as well as pore blocking model. All the different types of flux decline kinetics were found to occur during the permeation of glycerin-rich solutions. However, the contribution of resistance due to cake layer formation was small for all the conditions studied. The fouling mechanisms were found to depend on the hydrophobicity of the PES membrane itself as well as the nature of foulants used in the study.     

Essential oils of Alpinia conchigera Griff. and their antimicrobial activities

The essential oils from the dried leaves, pseudostems and rhizomes of Alpinia conchigera Griff. (KL 5049), collected from Jeli province of Kelantan, east coast of Peninsular Malaysia, were isolated by hydrodistillation. The collected oils were analyzed by capillary GC and GC–MS. Forty one compounds were identified, among which 13 have not been detected previously. The leaf, pseudostem and rhizome oils afforded 40, 33 and 39 constituents, respectively. The most abundant components in the leaf oil included β-bisabolene (15.3%), β-pinene (8.2%), β-sesquiphellandrene (7.6%), chavicol (7.5%) and β-elemene (6.0%), while β-bisabolene (19.9%), β-sesquiphellandrene (11.3%), β-caryophyllene (8.8%) and β-elemene (4.7%) were the main components in the pseudostem. In the rhizome, 1,8-cineole (17.9%), β-bisabolene (13.9%), β-sesquiphellandrene (6.8%) and β-elemene (4.0%) were the major components. The essential oils were also subjected to antifungal and antibacterial tests, using the minimum inhibitory concentration (MIC) method. Results revealed weak inhibitions against the microorganisms tested.     

Toward collective organizational values: a case study in UK construction

Despite privatization, many government‐linked companies (GLCs) still continue to operate in Malaysia. Many have objectives that include the redressing of ethnic economic imbalance. Government‐linked construction companies (GLCCs) were created within these larger public groups. A study was conducted to explore whether the GLCCs are still valid in Malaysia's present construction industry scenario, and if not, what actions should be taken in respect of them. Four aspects (i.e. social obligation, competitiveness, efficiency and income generation) were looked into. To answer the research questions, the viewpoints of ‘A’ Class bumiputera contractors were solicited which were then investigated on four GLCCs, three belonging to state economic development corporations (SEDCs) and one to a land development agency (LDA). The exploratory study found that three case study GLCCs have limited public value. This paper concludes by recommending changes that should be made to them. There is much that policy makers in developing countries with GLCCs can learn from the Malaysian experience. At the very least, it underscores the need to assess their raison d'être periodically. This study also hopes to encourage other scholars to look into a much under‐researched area—that of a particular set of actors commonly created to promote local construction industry development.     

中性硼硅玻璃与药物相容性研究进展

目的 药品包装材料与药物相容性实验是评价药品包装材料安全性能与药品质量的重要研究项目,中性硼硅玻璃具有膨胀系数小、耐极冷极热性强、不易炸裂、化学稳定性好等特点,已成为注射剂包装的首选材质.探索中性硼硅玻璃与药物相容性的研究进展与发展趋势,为中性硼硅玻璃用于药品包装材料提供参考.方法 分别从玻璃成分中金属离子向药液中的迁移量、有害物质的浸出量、不同温度与酸碱条件下玻璃的脱片、玻璃对药物的吸附以及药物对玻璃表面的侵蚀程度等方面综述中性硼硅玻璃与药物相容性的研究进展,考察中性硼硅玻璃对于药品质量的影响.结论 中性硼硅玻璃与药物的相容性评价方法逐渐完善,为中性硼硅玻璃作为药用包装材料的研究提供参考.     

Ferroelectric‒to‒relaxor crossover in KNN‒based lead‒free piezoceramics

This study investigated the phase transition behavior and electrical properties of (K_0.5Na_0.5)(Nb_1-xZr_x)O₃ (KNN?100xZ) and (K_0.5Na_0.5)NbO₃–yBaZrO₃ (KNN–100yBZ) lead–free piezoelectric ceramics. The phase transitions in crystal structures were compared in KNN ceramics between single Zr⁴⁺ doping and Ba²⁺Zr⁴⁺ co?doping. Piezoelectric properties such as the piezoelectric constant (d₃₃) and electromechanical coupling factor (k_p) are optimized for KNN?6BZ ceramics and were clarified via the polymorphic phase transition from the orthorhombic to pseudocubic phase. The fitted degree of diffuseness (γ) for a phase transition from the modified Curie–Weiss law indicated that KNN ceramics as ferroelectrics are gradually transformed through BaZrO₃ modification. Accordingly, the enhanced strain properties at y = 0.08 consist of coexisting ferroelectric domains and polar nanoregions that are supported by ferroelectric–to–relaxor crossover in KNN?100BZ ceramics.