Isolation and characterization of the microbial population of different South African kefir grains

Kefir, a slightly acidic fermented milk, is produced by adding lactic acid bacteria and yeasts, in the form of grains, to milk. The bacteria and yeasts present in the kefir grains are known to vary widely. Selective growth media and morphological and biochemical characteristics were used for the isolation and identification of the microbes present in the grains from eight different sources in South Africa. The kefir grains were activated in milk for only 24 h to prevent any changes in the microbial population of the grains. The microbial numbers varied between 6.4 × 10⁴ and 8.5 × 10 ⁸  cfu/g on the media selective for the bacterial species and between 1.5 × 10 ⁵ and 3.7 × 10 ⁸   cfu/g on the media selective for the yeast species. The bacterial genera that were identified included Lactobacillus , Leuconostoc and Lactococcus and the yeast genera included Zygosaccharomyces , Candida and Saccharomyces . The distribution frequencies of the microbes in the different grains were determined and most of the grains were dominated by two microbial species. No pediococci, acetic acid bacteria or propionibacteria were detected.     

Life-cycle assessment of diesel, natural gas and hydrogen fuel cell bus transportation systems

The Sustainable Transport Energy Programme (STEP) is an initiative of the Government of Western Australia, to explore hydrogen fuel cell technology as an alternative to the existing diesel and natural gas public transit infrastructure in Perth. This project includes three buses manufactured by DaimlerChrysler with Ballard fuel cell power sources operating in regular service alongside the existing natural gas and diesel bus fleets. The life-cycle assessment (LCA) of the fuel cell bus trial in Perth determines the overall environmental footprint and energy demand by studying all phases of the complete transportation system, including the hydrogen infrastructure, bus manufacturing, operation, and end-of-life disposal. The LCAs of the existing diesel and natural gas transportation systems are developed in parallel. The findings show that the trial is competitive with the diesel and natural gas bus systems in terms of global warming potential and eutrophication. Emissions that contribute to acidification and photochemical ozone are greater for the fuel cell buses. Scenario analysis quantifies the improvements that can be expected in future generations of fuel cell vehicles and shows that a reduction of greater than 50% is achievable in the greenhouse gas, photochemical ozone creation and primary energy demand impact categories.     

Fuel cycle analysis of GFR using advanced fuels

The potential benefits of a synergistic light-water reactor (LWR) and gas-cooled fast reactor (GFR) fuel cycle were evaluated for its impact on the front-end and back-end of the fuel cycle. Comparisons were made with conventional once-through cycle (OTC) and MOX fuel cycle. Variations in the synergistic LWR/GFR fuel cycles were based on the degree of recycle in the LWR including both plutonium and reprocessed uranium with concomitant impact on used LWR fuel inventory. This provided a wide range in composition of GFR feed from low to high plutonium content with impact on transmutation/incineration within the GFR fuel cycle. Self-recycle of all actinides was modeled for the GFR with analyses demonstrating that the GFR can be sustained on and consequently accept a wide range of feed materials. Analyses were done using Monteburns along with MCNP and Origen2.2 to model a 60-year period corresponding to the anticipated lifetime of supposed contemporary LWRs and GFRs. All cycles were evaluated based on actinide total mass and isotopic inventory, radiotoxicity, heatload, and resource requirements including natural uranium and SWU. For comparison, all fuel cycles were normalized based on 1 TWHe output. Improvements in fuel cycle performance are dictated by the production and incineration of minor actinides in the GFR and their continued recycle may not be feasible due to the buildup of troublesome isotopes such as ²⁴⁴Cm and ²⁵²Cf. But where uranium and plutonium continue to be recycled beyond the 60-year period, the LWR/GFR cycles demonstrated order of magnitude reductions in used fuel inventories, heatload, and radiotoxicity on a per TWHe basis over LWR only cycles. The full details of the advanced fuel cycle methodology and results are presented.     

过敏性皮肤贴身穿轻薄毛织物的主要医用规格

最新研究表明贴身穿细美利奴羊毛的衣服对敏感型皮肤的皮疹有一定的治疗作用。为了确保这类过敏性皮肤穿着的舒适性,文章利用澳大利亚羊业合作研究中心的穿着试验数据和成衣,借助新近研发的羊毛舒适仪,对过敏性皮肤贴身穿轻薄毛织物的医用规格进行了研究。通过相关性分析发现:纯羊毛织物的刺痒性能很大程度上决定了穿着者的皮肤舒适度。进而通过使用多元变量主成分分析,辨别出人们对羊毛织物刺痒性能在不同的穿着环境和不同的活动强度下的感应模式,从而对织物的刺痒性能进行分类。最后通过对试穿服装的纤维细度和舒适度指数进行测试分析,确定了该类贴身穿毛织物的主要医用规格。包括舒适度指数不高于200,纤维的平均直径不大于17.5μm,直径大于25μm的纤维含量不高于2.0%。     

Characterisation of the $$chi$$χ-index and the rec-index

Scientometrics - Axiomatic characterisation of a bibliometric index provides insight into the properties that the index satisfies and facilitates the comparison of different indices. A geometric...     

Starch determination in horticultural plant material by an enzymic-colorimetric procedure

The starch content of horticultural plant material (including leaves and woody tissues such as roots, stems, twigs, trunks and bark) was determined by an enzymic procedure. A heat-stable α-amylase and amyloglucosidase were used to hydrolyse the starch in the finely ground plant material to glucose. The glucose produced was measured colorimetrically using a coupled glucose oxidase/peroxidase reaction. Conditions necessary for maximum glucose recovery were established. Plant material analysed included samples from macadamia (Macadamia integrifolia Maiden and Betche, trunk and bark), mango (Mangifera indica L; stems and roots), lychee (Litchi chinensis Sonn; leaves, stems, twigs and roots), pineapple (Ananas comosus (L) Merrill; leaves, stems and roots) and nectarine (Prunus persica (L) Batsch var nucipersica (Suckow) C K Schneid; twigs, shoots, branches, limbs, roots and trunk). Starch values ranged from less than 14% to greater than 30%. The method allows assessment of variations in the starch content of perennial plants and may be used in crop management.     

3D Printing of Customized Drug Delivery Systems with Controlled Architecture via Reversible Addition-Fragmentation Chain Transfer Polymerization

3D printing via reversible addition-fragmentation chain transfer (RAFT) polymerization has been recently developed to expand the scope of 3D printing technologies. A potentially high-impact but relatively unexplored opportunity that can be provided by RAFT-mediated 3D printing is a pathway toward personalized medicine through manufacturing bespoke drug delivery systems (DDSs). Herein, 3D printing of drug-eluting systems with precise geometry, size, drug dosage, and release duration/profiles is reported. This is achieved through engineering a range of 3D models with precise interconnected channel-pore structure and geometric proportions in architectural patterns. Notably, the application of the RAFT process is crucial in manufacturing materials with highly resolved macroscale features by confining curing to exposure precincts. This approach also allows spatiotemporal control of the drug loading and compositions within different layers of the scaffolds. The ratio between the polyethylene glycol units and the acrylate units in the crosslinkers is found to be a critical factor, with a higher ratio increasing swelling capacity, and thus enhancing the drug release profile, from the drug-eluting systems. This proof-of-concept research demonstrates that RAFT-mediated 3D printing enables the production of personalized drug delivery materials, providing a pathway to replace the “one-size-fits-all” approach in traditional health care.     

Biomagnification of perfluoroalkyl compounds in the bottlenose dolphin (Tursiops truncatus) food web

The environmental distribution and the biomagnification of a suite of perfluoroalkyl compounds (PFCs), including perfluorooctane sulfonate (PFOS) and C8 to C14 perfluorinated carboxylates (PFCAs), was investigated in the food web of the bottlenose dolphin (Tursiops truncatus). Surficial seawater and sediment samples, as well as zooplankton, fish, and bottlenose dolphin tissue samples, were collected at two U.S. locations: Sarasota Bay, FL and Charleston Harbor, SC. Wastewater treatment plant (WWTP) effluents were also collected from the Charleston area (n = 4). A solid-phase extraction was used for seawater and effluent samples and an ion-pairing method was used for sediment and biotic samples. PFCs were detected in seawater (range <1-12 ng/L), sediment (range <0.01-0.4 ng/g wet weight (ww)), and zooplankton (range 0.06-0.3 ng/g ww). The highest PFC concentrations were detected in WWTP effluents, whole fish, and dolphin plasma and tissue samples in which PFOS, C8 and C10-PFCAs predominated in most matrices. Contamination profiles varied with location suggesting different sources of PFC emissions. Biomagnification factors (BMFs) ranged from <1 to 156 at Sarasota Bay and <1 to 30 at Charleston. Trophic magnification factors (TMFs) for PFOS and C8-C11 PFCAs indicated biomagnification in this marine food web. The results indicate that using plasma and liver PFC concentrations as surrogate to whole body burden in a top marine predator overestimates the BMFs and TMFs.     

Managing job seekers' organizational image beliefs: The role of media richness and media credibility.

In this article, the authors assessed job seekers' organizational image beliefs before and after they experienced 3 recruitment media. The authors examined whether perceptions of media richness and credibility were related to improvements in the correspondence between job seekers' image beliefs and firms' projected images. Both media richness and credibility perceptions were associated with correspondence between job seekers' image beliefs and firms' projected images. However, results revealed that richness and credibility perceptions were likely to enhance job seekers' initial beliefs about firms' images when their beliefs were positive but did not diminish job seekers' beliefs about firms' images when their initial impressions were too positive. (PsycINFO Database Record (c) 2010 APA, all rights reserved)