Stabilization of highly concentrated suspensions of iron nanoparticles using shear-thinning gels of xanthan gum

Nanoscale zerovalent iron (NZVI) particles have recently become subject of great interest in the field of groundwater remediation for their ability to treat a wide variety of organic and inorganic contaminants. However, the field application of this technology is strongly hindered by the lack of stability of NZVI water suspensions.This study demonstrates that highly concentrated NZVI slurries (15 g/L) can be stabilized for more than 10 days adding 6 g/L of xanthan gum biopolymer. Stability against aggregation and sedimentation was achieved in the range of ionic strength 6 × 10⁻³–12 mM and is mainly due to the formation of a viscous gel characterized by shear-thinning behaviour.     

Flexibility in manufacturing: A survey

This article is an attempt to survey the vast literature on flexibility in manufacturing that has accumulated over the last 10 to 20 years. The survey begins with a brief review of the classical literature on flexibility in economics and organization theory, which provides a background for manufacturing flexibility. Several kinds of flexibilities in manufacturing are then defined carefully along with their purposes, the means to obtain them, and some suggested measurements and valuations. Then we examine the interrelationships among the several flexibilities. Various empirical studies and analytical/optimization models dealing with these flexibilities are reported and discussed. The article concludes with suggestions for some possible future research directions.     

对运用压电陶瓷智能材料土木工程结构的振动控制回顾和总结

对土木工程中结构的振动控制进行了总结,对具有压电控制驱动的智能结构给予重点总结。过去的十年中,全世界范围内智能结构在螺旋形地发展着。这些智能结构方面的成就主要依靠材料来实现,如压电陶瓷、形状记忆合金、可控流体如磁流变液、电流变液、光纤维传感器和多种其他材料。压电陶瓷是一种低成本、轻质、便于成型的材料,可应用于结构振动的主动控制。压电陶瓷有多种形式如刚性片、柔性片、叠层式压电陶瓷堆、粗纤维复合驱动器和压电陶瓷摩擦阻尼器。只需要对原始结构做出轻微的改变,就可以将压电陶瓷驱动器粘结在结构高应变区域的表面,或者将其植入结构中形成组合结构。另一方面,在对原结构做出轻微改进之后,叠放型驱动器可以与这种需要高控制力和微小位移的结构结合成一体。首先介绍了压电陶瓷材料、各种驱动控制方法和压电陶瓷驱动器的类型,然后回顾了压电陶瓷驱动器在各种不同类型的土木工程结构中如梁、桁架、钢框架和悬索桥等的应用研究。     

The Immunometabolic Roles of Various Fatty Acids in Macrophages and Lymphocytes

Macrophages and lymphocytes demonstrate metabolic plasticity, which is dependent partly on their state of activation and partly on the availability of various energy yielding and biosynthetic substrates (fatty acids, glucose, and amino acids). These substrates are essential to fuel-based metabolic reprogramming that supports optimal immune function, including the inflammatory response. In this review, we will focus on metabolism in macrophages and lymphocytes and discuss the role of fatty acids in governing the phenotype, activation, and functional status of these important cells. We summarize the current understanding of the pathways of fatty acid metabolism and related mechanisms of action and also explore possible new perspectives in this exciting area of research.     

Antimicrobial resistance patterns of bovine Salmonella enterica isolates submitted to the Wisconsin Veterinary Diagnostic Laboratory: 2006–2015

Salmonellosis on the dairy continues to have a significant effect on animal health and productivity and in the United States. Additionally, Salmonella enterica ssp. enterica causes an estimated 1.2 million cases of human illness annually. Contributing to the morbidity and mortality in both human and domestic animal species is emergence of antimicrobial resistance by Salmonella species and increased incidence of multidrug-resistant isolates. This study describes serotype distribution and the antimicrobial resistance patterns for various Salmonella serotypes isolated from bovine samples submitted to the Wisconsin Veterinary Diagnostic Laboratory (WVDL) over the past 10 yr. Salmonella serotyping and antimicrobial susceptibility testing data were obtained from the laboratory information management system at WVDL. Data from accessions were limited to bovine samples submitted to the WVDL between January 2006 and June 2015 and those that had both a definitive serotype and complete results for antimicrobial susceptibility testing. A total of 4,976 isolates were identified. Salmonella enterica ser. Dublin was the most prevalent serotype identified among bovine samples submitted to the WVDL, accounting for a total of 1,153 isolates (23% of total isolates) over the study period. Along with Dublin, Salmonella enterica ser. Cerro (795, 16%), Newport (720, 14%), Montevideo (421, 8%), Kentucky (419, 8%), and Typhimurium (202, 4%) comprised the top 6 most commonly isolated serotypes during that time. Overall, resistance of bovine Salmonella isolates in the study population remained stable, although decreases in resistance were noted for gentamicin, neomycin, and trimethoprim sulfamethoxazole during the study period. All isolates remained susceptible to enrofloxacin. These data show that antimicrobial susceptibility for bovine Salmonella has changed in the population served by WVDL in the past 10 yr. This information is important for understanding Salmonella disease ecology in Wisconsin. Our findings are also relevant for animal and public health by improving informed antimicrobial use, new drug development, and regulation of their use in food animals.     

Nitroxide Radicals@US‐Tubes: New Spin Labels for Biomedical Applications

The encapsulation of nitroxide radicals within ultrashort (ca. 50 nm) single‐walled carbon nanotubes (US‐tubes) is achieved. Tempo‐ and Iodo‐Tempo@US‐tubes are characterized by thermogravimetric analysis (TGA), X‐ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Electron paramagnetic resonance (EPR) spectra display characteristic signals due to the detection of the spin probes within the US‐tubes. Longitudinal proton relaxivities (r₁) of both nitroxide@US‐tubes samples are 7 to 13 times greater than the free nitroxide radicals in solution, giving relaxivities comparable to the clinical contrast agent (CA) Magnevist. In addition, transverse proton relaxivities (r₂) show unprecedented proton relaxation enhancement in comparison to any other reported nitroxide radical‐based system or the clinically approved T₂ CA, Resovist, under the same conditions. T₂‐weighted magnetic resonance imaging (MRI) phantom images show that the encapsulation of nitroxide radicals within the US‐tubes produces good contrast enhancement due to their high r₂ relaxivities. The nitroxide radicals@US‐tube agents are a new promising class of spin probes for MRI and electronic paramagnetic resonance imaging (EPRI) labeling, tracking, and diagnosis.     

Survey and evaluation of heating technologies for worldwide agricultural greenhouse applications

This paper reviews and evaluates all the available heating technologies for worldwide agricultural greenhouses and discusses the representative applications of each technology. Available information on the location, ground area, cover materials and performance of the greenhouses coupled with each technology such as water storage (including solar flat plate collectors, ground-source heat pumps and shallow solar ponds), rock bed storage, phase change material storage and earth-to-air heat exchanger system is collected and presented in detail. Using the collected information an attempt has been made to correlate the approximate storage volume or weight of the material required for a given greenhouse area for different storage media under various greenhouse cover materials. These relations can be of great importance to the potential users for the successful development of future applications. Apart from the above-mentioned technologies, a complete review and performance evaluation of other greenhouse heating technologies such as movable insulation, north wall storage, ground air collector and aquifer coupled cavity flow heat exchanger system is also presented. Heating potential (overall performance) of each system under different cover materials along with their advantages, limitations and suitability is also discussed.