Stable Isotope Probing to Confirm Field‐Scale Co‐Metabolic Biodegradation of 1,4‐Dioxane

1,4‐Dioxane, a common co‐contaminant with chlorinated solvents, is present in groundwater at Site 24 at Vandenberg Air Force Base in California. Historical use of chlorinated solvents resulted in concentrations of 1,4‐dioxane in groundwater up to approximately 2,000 μg/L. Starting in 2013, an in situ propane biosparge system operation demonstrated reductions in 1,4‐dioxane concentrations in groundwater. The work detailed herein extends the efforts of the first field demonstration to a second phase and confirms the biodegradation mechanism via use of stable isotope probing (SIP). After two months of operation, 1,4‐dioxane concentrations decreased approximately 45 to 83 percent at monitoring locations in the test area. The results of the SIP confirmed ¹³C‐enriched 1,4‐dioxane was transformed into dissolved inorganic carbon (suggesting mineralization to carbon dioxide) and incorporated into microbial biomass (likely attributed to metabolic uptake of biotransformation intermediates or of carbon dioxide).  ©2016 Wiley Periodicals, Inc.     

Modeling and inference of animal movement using artificial neural networks

Movement of animals in relation to objects in their environment is important in many areas of ecology and wildlife conservation. Tools for analysis of movement data, however, still remain rather limited. In previous work, we developed nonlinear regression models for movement in relation to a single landscape feature. Here we greatly expand these previous models by using artificial neural networks. The new models add substantial flexibility and capabilities, including the ability to incorporate multiple factors and covariates. We devise a likelihood-based model fitting procedure that utilizes genetic algorithms and demonstrate the approach with movement data for red diamond rattlesnakes. The proposed methodology can be useful for global positioning system tracking data that are becoming more common in studies of animal movement behavior.     

Bioaerosols as contributors to poor air quality in Taichung City, Taiwan

Bioaerosols are a type of suspended sediments that contribute to poor air quality in Taiwan. Bioaerosols include allergens such as: fungi, bacteria, actinomycetes, arthropods and protozoa, as well as microbial products such as mycotoxins, endotoxins and glucans. When allergens and microbial products are suspended in the air, local air quality will be influenced adversely. In addition, when the particle size is small enough to pass through the respiratory tract entering the human body, the health of the local population is also threatened. Therefore, the purpose of this study is to attempt to understand the concentration and types of bacteria and the bacteria numbers for various particle size ranges during a study period of June 2005 to February 2006 in Taichung City, Central Taiwan. The results indicate that the total average bacterial concentration by using NA medium incubated for 48 h were 8.0 × 10², 1.4 × 10³, 2.4 × 10³ and 1.3 × 10³, 1.9 × 10³, 3.5 × 10³ cfu/m³ for CMES, TRIPS and RFS sampling sites during the daytime and nighttime period of June 2005 to February 2006. Moreover, the total average bacterial concentration by using R₂A medium incubated for 48 h were 8.5 × 10², 1.5 × 10³, 2.2 × 10³ and 1.2 × 10³, 1.7 × 10³, 2.5 × 10³ cfu/m³ for CMES, TRIPS and RFS sampling sites the daytime and nighttime during the same sampling period. The total average bacteria concentration was the same in either NA or R₂A medium for the same sampling times or sites. The total average bacterial concentration was higher in daytime period than that of nighttime period for CMES, TRIPS and RFS sampling sites. The high average bacterial concentration was found in the particle size range of 0.53–0.71 mm (average bioaerosol size was in the range of 2.1–4.7 μm) for each sampling site. Also, 20 kinds of bacteria exceeded levels for each sampling site and were classified as according to shape: rod, coccus and filamentous.     

Biotransformation of p-toluic acid in anoxic estuarine sediments under a CO2 or N2/H2 atmosphere.

The composition of the headspace gas affected the growth dynamics of microbial populations and the biotransformation pattern of p-toluic acid in anoxic estuarine sediments. Under CO2 atmosphere, p-toluic acid was transformed by the sediment microorganisms without a lag period, while under N2/H2 atmosphere, p-toluic acid was transformed after a lag period of 55 days. Under the N2/H2 atmosphere, the methanogen population, following a rapid increase of almost two orders of magnitude, remained at a high level until just before the onset of biotransformation. We hypothesize that during the lag period, the hydrogenotrophic methanogens were removing the H2, a step which is essential before the reaction can be exergonic. Acetogenic bacteria did not initiate decarboxylation as the first step of biotransformation under either atmosphere. Neither the methanogens nor the acetogenic bacteria appeared to be directly involved in the biotransformation of p-toluic acid under either atmosphere. Under the CO2 atmosphere, biotransformation of p-toluic acid involved sulfate-reducing bacteria, while under N2/H2, both sulfate-reducing bacteria and other eubacteria were involved.     

Impact of the 1998 Central American fires on PM2.5 mass and composition in the southeastern United States

The impact of the Central American fires on PM_2.5 mass concentration and composition in the Tennessee Valley region during portions of May, 1998, has been quantified. Elevated concentrations of smoke aerosol tracers—fine potassium, (and to a lesser extent, calcium and silicon) and, where available, organic and elemental carbon—were observed in the region during times in which satellite imagery (TOMS and GOES-8) showed regional transport of hazy, smoky airmasses from southern Mexico and adjacent areas of Central America. Back-trajectories from network sites in the Tennessee Valley network were consistent with this regional transport. The extent of transport of extra-regional fine particle mass during May, 1998, is discussed relative to the new US fine particle mass-based standards for fine particulate matter.     

Late-onset growth restriction in Galloway–Mowat syndrome: a case report

Galloway–Mowat syndrome (GMS) is a rare autosomal recessive disorder and is characterized by marked intrauterine growth retardation, central nervous system anomalies, and early onset nephrotic syndrome. Of the reported cases in the literature, all were diagnosed postnatally. We describe a case of GMS in which only late-onset intrauterine growth restriction was detected by prenatal ultrasound. In her fourth pregnancy, the mother had delivered a male baby with clinical features of GMS who died at seven months of age due to early onset of nephrotic syndrome. In her fifth pregnancy, serial ultrasound examinations were normal during the first and second trimester of pregnancy. Growth restriction and microcephaly were not detectable until 28 to 32 weeks' gestation. At 40 weeks' gestation, a female baby was born with dysmorphic features of GMS. Nephrotic syndrome developed after birth and renal biopsy revealed minimal change nephrotic syndrome. The prenatal course of this case suggests GMS may not be diagnosed in early pregnancy and the only abnormality detected before birth was intrauterine growth restriction. Copyright © 2005 John Wiley & Sons, Ltd.     

Study on safe air transporting velocity of nanograde aluminum,iron, and titanium

The process of delivering nanograde metal powders by a high-speed carrier gas is often subject to high explosion risks. This study adopted initial flow rates of 13.1, 8.5, 6.5, and 3.5 m/s for air transporting 30-nm titanium powder, 35-nm iron powder, and 35-nm aluminum powder to gauge the impact on a pipe bend in a 20-l-apparatus. The test results revealed that the 30-nm titanium powder caused an explosion at all initial flow rates; the 35-nm iron powder also caused an explosion, but dust explosion and sintering were eliminated when the flow rate was adjusted to less than 3.5 m/s; and the 35-nm aluminum powder exhibited no explosion or sintering at all flow rates. When pure nitrogen was used for transporting nanograde metal powders, no explosions occurred for all the three types of metal powders. The minimum ignition energy for these three types of nanograde metal powders was less than 1 mJ.     

Cyber first aid: proactive risk management and decision-making

Public and private organizations need a robust approach to prepare, respond, and recover from cyber-attacks. This perspective article will refer to such an approach as Cyber First AID—adaptable, integrated, and deliberate. Adaptable describes that one size does not fit all; Integrated means the effort is throughout the organization; and Deliberate describes plans that are reviewed periodically and practiced, in which all members of the organization know their respective roles and responsibilities. The article outlines a decision-making process for how to minimize the impacts of cyber threats, maintain stakeholder and customer confidence, and help organizations to adaptively manage and respond to cyber threats in rapidly changing cyber environments.     

Associations of long-term ambient air pollution and traffic-related pollution with blood pressure and hypertension defined by the different guidelines worldwide: the CHCN-BTH study

Environmental Science and Pollution Research - The assessment of the generalization of the strict hypertension definition in the 2017 ACC/AHA Hypertension Guideline from environmental condition...