bluuebunny/crossref_metadata_2025 huggingface dataset:
Single unit activity of periaqueductal gray and deep mesencephalic nucleus neurons involved in sleep stage switching in the mouse
Authors: Sakai K.
Published: March 2018

A total of 668 single units were recorded in the mouse periaqueductal gray (PAG) and adjacent deep mesencephalic nucleus (DpMe) to determine their role in the switching of sleep–wake states, that is, wakefulness (W), slow‐wave sleep (SWS) and paradoxical (or rapid eye movement) sleep (PS) in general, and, in particular, to determine whether PS‐on and PS‐off neurons involved in PS state switching are present in these structures and to identify neuronal substrates for the SWS‐PS switching mediated by DpMe neurons. Both structures were found to contain similar percentages of W/PS‐active neurons, which discharge at a higher rate during W and PS than during SWS, while W‐active neurons, which discharge maximally during W, were found mainly in the PAG. Both also contained similar percentages of SWS/PS‐active neurons, which discharge at higher rates during SWS and PS than during W, and PS‐active neurons, which discharge maximally during PS, while SWS‐active neurons, which discharge maximally during SWS, were found almost exclusively in the PAG. Both structures contained virtually no PS‐on or PS‐off neurons, which, respectively, discharge or cease firing selectively and tonically just prior to, and during, PS. Unlike the PAG, the DpMe contained many SWS/PS‐on neurons, which discharge selectively at high rates during SWS and PS, but show a decrease in discharge rate at the transition from SWS to PS. Analysis of discharge profiles and trends in spike activity at the state transitions strongly suggests that PAG and DpMe neurons play an important role in the W‐SWS, SWS‐PS and/or PS‐W switches.
“Now We Live for the Money”: Shifting Markers of Status, Stress, and Immune Function in the Peruvian Amazon
Authors: Tallman Paula
Published: March 2018

This article examines the relationship between cultural changes, socioeconomic status (SES), and psychobiological health outcomes among the Awajún, an indigenous group living in the Peruvian Amazon. Specifically, it documents how historically important markers of status for the Awajún, such as spiritual visions and war‐time success, were replaced by Western markers of status including occupation, income, education and Spanish‐language use. These changes are linked to the broader political‐economic and social agendas of Peruvian government officials and American missionaries who sought religious conversion and economic gain in the deepest reaches of the Amazon. The resulting socioeconomic hierarchies have implications for the health and well‐being of Awajún men and women in the present. Independent of other relevant factors such as age and community, men with lower SES tended to have higher Epstein‐Barr Virus (EBV) antibodies, indicating suppressed immune function, and both men and women with lower SES tended to have higher reported psychological stress levels. This critical biocultural analysis suggests that existing socioeconomic hierarchies in Awajún communities are the result of active colonial, evangelical, and capitalist efforts and shows that local histories and social spheres “get under the skin” to influence the mind and body. [lifestyle change, socioeconomic status (SES), psychological stress, Epstein‐Barr Virus (EBV) antibodies, Amazon, Awajún]
The Ethic of Spirituality and the Non‐Angry Subject
Authors: Simchai Dalit , Shoshana Avihu
Published: March 2018

This article is based on ethnographic studies of several spiritual groups in Israel. It offers a critical analysis of the discursive practices employed with regard to the link between spirituality and anger. We found that the emotion of anger occupies a singular status in New Age culture. By marking it as an uncontrollable and explosive emotion, anger is constructed as a key emotion that reflects and signifies the subject's proximity to the ideal spiritual personality. Our findings furthermore reveal two main emotion pedagogies employed to construct anger and to cope with it. In the discussion section, we address the affinity between the spiritual ethic and the nonangry subject, and the alliance between the spiritual, the therapeutic and the neo‐liberal discourses that sustains this affinity. This discursive alliance stands in the way of the adoption of critical cultural orientations toward the emotion of anger. [spirituality, emotions, anger, subjectivity, discursive alliance, emotion pedagogies]
Short‐ and long‐term evolution in our arms race with cancer: Why the war on cancer is winnable
Authors: Rosenheim Jay A.
Published: March 2018

Human society is engaged in an arms race against cancer, which pits one evolutionary process—human cultural evolution as we develop novel cancer therapies—against another evolutionary process—the ability of oncogenic selection operating among cancer cells to select for lineages that are resistant to our therapies. Cancer cells have a powerful ability to evolve resistance over the short term, leading to patient relapse following an initial period of apparent treatment efficacy. However, we are the beneficiaries of a fundamental asymmetry in our arms race against cancer: Whereas our cultural evolution is a long‐term and continuous process, resistance evolution in cancer cells operates only over the short term and is discontinuous — all resistance adaptations are lost each time a cancer patient dies. Thus, our cultural adaptations are permanent, whereas cancer's genetic adaptations are ephemeral. Consequently, over the long term, there is good reason to expect that we will emerge as the winners in our war against cancer.
Multiple pharmacological approaches on Fibigia eriocarpa extracts by in vitro and computational assays
Authors: Zengin Gokhan , Lobine Devina , Mollica Adriano , Locatelli Marcello , Carradori Simone , Mahomoodally Mohamad Fawzi
Published: March 2018

The ethyl acetate, methanolic, and water extracts of Fibigia eriocarpa were assessed for a panoply of bioactivities. Total phenolic and flavonoid content were quantified as well as individual phenolic compounds by HPLC‐DAD. The in vitro antioxidant and enzyme (acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, α‐amylase, and α‐glucosidase) inhibitory potential of the extracts were evaluated. In silico molecular docking was used to investigate possible interaction between dominant compounds and selected enzymes. Vanillin (303 μg/g extract), apigenin (270 μg/g extract), and kaempferol (180 μg/g extract) were the main compounds in the ethyl acetate extract, while the methanolic extract was characterized by the presence of vanillin, rutin, and apigenin (616, 616 and 252 μg/g extract, respectively). (+)‐catechin (1422 μg/g extract) was the main compound in the water extracts. The ethyl acetate extract was found to be a superior source of antioxidant compounds and enzyme inhibitors against above‐mentioned enzymes. Docking studies revealed that p‐hydroxybenzoic and (+)‐catechin have the best scores for tyrosinase, while kaempferol and apigenin showed the best binding pose for α‐glucosidase, AChE, and BChE. Results amassed herein are the first report on the phytochemical and biological attributes of F. eriocarpa, which tend to validate the pharmacological uses of this plant as an alternative medicine.
Population collapse dynamics in Acropora downingi, an Arabian/Persian Gulf ecosystem‐engineering coral, linked to rising temperature
Authors: Riegl Bernhard , Johnston Matthew , Purkis Sam , Howells Emily , Burt John , Steiner Sascha C. C. , Sheppard Charles R. C. , Bauman Andrew
Published: March 2018

As in the tropical Atlantic, Acropora populations in the southern Persian/Arabian Gulf plummeted within two decades after having been ecosystem engineers on most wave‐exposed reefs since the Pleistocene. Since 1996/1998 live coral cover in the Gulf declined by over 90% in many areas, primarily due to bleaching and diseases caused by rising temperatures. In the formerly dominant table‐coral species A. downingi, population dynamics corresponding to disturbance regimes was quantified in three transition matrices (lower disturbance pre‐1996; moderate disturbance from 1998 to 2010 and 2013 to 2017, disturbed in 1996/1998, 2010/11/12, 2017). Increased disturbance frequency and severity caused progressive reduction in coral size, cover, and population fecundity. Small size‐classes were bolstered more by partial colony mortality than sexual recruitment. Some large corals had a size refuge and resisted die‐back but were also lost with increasing disturbance. Matrix and biophysical larval flow models suggested one metapopulation. Southern, Arabian, populations could be connected to northern, Iranian, populations but this connectivity was lost under assumptions of pelagic larval duration at rising temperatures shortened to a third. Then, the metapopulation disintegrated into isolated populations. Connectivity required to avoid extinctions increased exponentially with disturbance frequency and correlation of disturbances across the metapopulation. Populations became unsustainable at eight disturbances in 15 years, when even highest theoretical recruitment no longer compensated mortality. This lethal disturbance frequency was 3‐fold that of the moderately disturbed monitoring period and 4‐fold of the preceding low‐disturbance period—suggesting ongoing shortening of the disturbance‐free period. Observed population collapse and environmental changes in the Gulf suggest that A. downingi is heading toward at least functional extinction mainly due to increasingly frequent temperature‐induced mortality events, clearly linked to climate change.
Effectiveness of preoperative physical therapy for older patients with hip fracture
Authors: Sawaguchi Akira , Momosaki Ryo , Hasebe Kiyotaka , Chono Masayuki , Kasuga Seiji , Abo Masahiro
Published: March 2018

Aim

To clarify the effectiveness of preoperative physical therapy for older patients after hip fracture in an acute care hospital.

Methods

In the present retrospective observational study, data from the Japan Rehabilitation Database were analyzed for patients admitted to an acute care hospital with hip fracture between 2005 and 2015. In this study, all eligible patients received surgery within 10 days of admission. Propensity score analysis was used to compare outcomes between patients who underwent preoperative rehabilitation and those who did not. The primary outcome was motor Functional Independence Measure (FIM) gain.

Results

Of the 681 patients eligible after applying exclusion criteria, 50% underwent preoperative rehabilitation after hip fracture. Both before and after adjustment by inverse probability weighting, motor FIM gain was significantly higher in patients who underwent preoperative rehabilitation (motor FIM gain 31.1 ± 18.2 before weighting, 31.1 ± 18.2 after weighting) than in those who did not (motor FIM gain 24.6 ± 18.1 before weighting, P < 0.01; 26.2 ± 17.6 after weighting, P < 0.02). In addition, motor FIM effectiveness and motor FIM at discharge were significantly higher among patients who underwent preoperative rehabilitation.

Conclusions

Our data suggest that preoperative rehabilitation after hip fracture is associated with better rehabilitation outcomes than no preoperative rehabilitation. Geriatr Gerontol Int 2018; 18: 1003–1008.
Mg Isotope Interlaboratory Comparison of Reference Materials from Earth‐Surface Low‐Temperature Environments
Authors: Shalev Netta , Farkaš Juraj , Fietzke Jan , Novák Martin , Schuessler Jan A. , Pogge von Strandmann Philip A.E. , Törber Philip B.
Published: March 2018

To enable quality control of measurement procedures for determinations of Mg isotope amount ratios, expressed as δ26Mg and δ25Mg values, in Earth‐surface studies, the δ26Mg and δ25Mg values of eight reference materials (RMs) were determined by interlaboratory comparison between five laboratories and considering published data, if available. These matrix RMs, including river water SLRS‐5, spring water NIST SRM 1640a, Dead Sea brine DSW‐1, dolomites JDo‐1 and BCS‐CRM 512, limestone BCS‐CRM 513, soil NIST SRM 2709a and vegetation NIST SRM 1515, are representative of a wide range of Earth‐surface materials from low‐temperature environments. The interlaboratory variability, 2s (twice the standard deviation), of all eight RMs ranges from 0.05 to 0.17‰ in δ26Mg. Thus, it is suggested that all these materials are suitable for validation of δ26Mg and δ25Mg determinations in Earth‐surface geochemical studies.
Altering Dissolved Oxygen to Determine Flow Conditions in Fractured Bedrock Wells
Authors: Chlebica Dariusz W. , Robbins Gary A.
Published: March 2018

A new approach to locate transmissive fractures and decipher vertical borehole flow conditions in fractured crystalline bedrock wells is presented, which uses dissolved oxygen (DO) as a benign tracer. The method was tested in two fractured crystalline bedrock wells previously characterized by televiewer and flow meter logging under both ambient and stressed (slug test) conditions. The method entailed elevating wellbore DO concentrations by circulating water through showerheads or injection of compressed air. The DO dilution was used to locate inflowing fractures. Changes in the DO concentration with time were used to ascertain flow within the borehole and to locate outflowing fractures and stagnant zones. Flow rates were also estimated. Fractures detected by the method corresponded to those observed by televiewer logging and for the most part were comparable to flow meter results. Given the effectiveness, time‐efficiency and low cost, the method is a promising alternative to other methods currently in use to characterize transmissive fractures in wells.
Using DNA‐Stable Isotope Probing to Identify MTBE‐ and TBA‐Degrading Microorganisms in Contaminated Groundwater
Authors: Key Katherine C. , Sublette Kerry L. , Duncan Kathleen , Mackay Douglas M. , Scow Kate M. , Ogles Dora
Published: March 2018

Although the anaerobic biodegradation of methyl tert‐butyl ether (MTBE) and tert‐butyl alcohol (TBA) has been documented in the laboratory and the field, knowledge of the microorganisms and mechanisms involved is still lacking. In this study, DNA‐stable isotope probing (SIP) was used to identify microorganisms involved in anaerobic fuel oxygenate biodegradation in a sulfate‐reducing MTBE and TBA plume. Microorganisms were collected in the field using Bio‐Sep® beads amended with 13C5‐MTBE, 13C1‐MTBE (only methoxy carbon labeled), or 13C4‐TBA. 13C‐DNA and 12C‐DNA extracted from the Bio‐Sep beads were cloned and 16S rRNA gene sequences were used to identify the indigenous microorganisms involved in degrading the methoxy group of MTBE and the tert‐butyl group of MTBE and TBA. Results indicated that microorganisms were actively degrading 13C‐labeled MTBE and TBA in situ and the 13C was incorporated into their DNA. Several sequences related to known MTBE‐ and TBA‐degraders in the Burkholderiales and the Sphingomonadales orders were detected in all three 13C clone libraries and were likely to be primary degraders at the site. Sequences related to sulfate‐reducing bacteria and iron‐reducers, such as Geobacter and Geothrix, were only detected in the clone libraries where MTBE and TBA were fully labeled with 13C, suggesting that they were involved in processing carbon from the tert‐butyl group. Sequences similar to the Pseudomonas genus predominated in the clone library where only the methoxy carbon of MTBE was labeled with 13C. It is likely that members of this genus were secondary degraders cross‐feeding on 13C‐labeled metabolites such as acetate.
Ambient Changes in Tracer Concentrations from a Multilevel Monitoring System in Basalt
Authors: Bartholomay Roy C. , Twining Brian V. , Rose Peter E.
Published: March 2018

Starting in 2008, a 4‐year tracer study was conducted to evaluate ambient changes in groundwater concentrations of a 1,3,6‐naphthalene trisulfonate tracer that was added to drill water. Samples were collected under open borehole conditions and after installing a multilevel groundwater monitoring system completed with 11 discrete monitoring zones within dense and fractured basalt and sediment layers in the eastern Snake River aquifer. The study was done in cooperation with the U.S. Department of Energy to test whether ambient fracture flow conditions were sufficient to remove the effects of injected drill water prior to sample collection. Results from thief samples indicated that the tracer was present in minor concentrations 28 days after coring, but was not present 6 months after coring or 7 days after reaming the borehole. Results from sampling the multilevel monitoring system indicated that small concentrations of the tracer remained in 5 of 10 zones during some period after installation. All concentrations were several orders of magnitude lower than the initial concentrations in the drill water. The ports that had remnant concentrations of the tracer were either located near sediment layers or were located in dense basalt, which suggests limited groundwater flow near these ports. The ports completed in well‐fractured and vesicular basalt had no detectable concentrations.
Geophysical and Hydrochemical Identification of Flow Paths with Implications for Water Quality at an ARR Site
Authors: Parsekian Andrew D. , Regnery Julia , Wing Alex D. , Knight Rosemary , Drewes Jörg E.
Published: March 2018

Two key challenges regarding the design and operation of aquifer recharge and recovery (ARR) systems are evaluating aquifer heterogeneity and understanding hydrochemical interactions. Uncertainty in this respect can impact the volume of recoverable water and the improvement in water quality. The objective of this research is to leverage the advantages of geophysical measurements and hydrochemical sampling to reveal the properties of an ARR site to inform current ARR system operations and future design decisions. Electrical resistivity tomography was used to image the subsurface below two key infiltration/extraction areas of an ARR site in Colorado, USA. Hydrochemical measurements on transects intersecting the geophysical measurements resolved bulk parameters (i.e., total organic carbon, nitrate, and major cations and anions) and trace organic chemicals (e.g., pharmaceuticals, personal care products). Conservative tracers were also used to estimate degrees of mixing and water travel times and to better assess the performance of the ARR site regarding water quality changes and water recovery. The electrical resistivity measurements suggest that certain areas of the infiltration basins have hydraulic connections to the extraction wells through preferential flow paths, compared with other infiltration basins that are separated by fine‐grained materials from their respective extraction wells. The hydrochemical results indicate that consistent improvements in water quality can be achieved in these preferential flow paths within relatively short travel times (<5 d) at this ARR site.
Effects of Fall vs. Spring Plowing Forages on Nitrate Leaching Losses to Groundwater
Authors: Jiang Yefang , Jamieson Terra , Nyiraneza Judith , Somers George , Thompson Barry , Murray Brian , Grimmett Mark , Geng Xiaoyuan
Published: March 2018

High levels of nitrate leaching losses from potato rotation systems have caused concerns for both drinking water quality and aquatic ecosystem protection in Prince Edward Island (PEI). Paired‐field experiments were carried out in commercial fields to evaluate the potential of delayed plowing forages within potato rotation from fall to spring on reducing nitrate leaching at two separate sites in PEI during 2010 and 2013. Monitoring showed that fall plowing resulted in elevated tile‐drain nitrate concentrations compared to spring plowing, probably mainly due to crop residue mineralization during fall which was hastened by earlier herbicidal termination of forage (i.e., herbicidal killing) at Site 1. A similar trend was also observed regarding nitrate concentrations of shallow groundwater at Site 2 during the forage phase. The practice of delaying the plowing of forages and/or associated earlier herbicidal termination of forage until spring reduces forage‐phase nitrate leaching loss by 20 to 61%, and should therefore be encouraged for nitrate mitigation. The study also demonstrated that only a small fraction (9.6 to 22%) of the fall plow‐down forages decayed during the forage phase and a large portion was retained in the soil into the next season. Growers should consider accounting for some of the carried‐over N for the subsequent crops regardless implementing fall or spring plowing.
Field Test of Enhanced Remedial Amendment Delivery Using a Shear‐Thinning Fluid
Authors: Truex Michael J. , Vermeul Vince R. , Adamson David T. , Oostrom Mart , Zhong Lirong , Mackley Rob D. , Fritz Brad G. , Horner Jake A. , Johnson Tim C. , Thomle Jonathan N. , Newcomer Darrell R. , Johnson Chris D. , Rysz Michal , Wietsma Tom W. , Newell Charles J.
Published: March 2018

Heterogeneity of hydraulic properties in aquifers may lead to contaminants residing in lower‐permeability zones where it is difficult to deliver remediation amendments using conventional injection processes. The focus of this study is to examine use of a shear‐thinning fluid (STF) to improve the uniformity of remedial amendment distribution within a heterogeneous aquifer. Previous studies have demonstrated the significant potential of STFs for improving remedial amendment delivery in heterogeneous aquifers, but quantitative evaluation of these improvements from field applications is lacking. A field‐scale test was conducted that compares data from successive injection of a tracer in water followed by injection of a tracer in an STF to evaluate the impact of the STF on tracer distribution uniformity in the presence of permeability contrasts within the targeted injection zone. Data from tracer breakthrough at multiple depth‐discrete monitoring intervals and electrical resistivity tomography (ERT) showed that inclusion of STF in the injection solution improved the distribution of the injected fluid within the targeted treatment zone. One improvement was a reduction in the movement of injected fluids through high‐permeability pathways, as evidenced by slower breakthrough of tracer at monitoring locations where breakthrough in baseline tracer‐only injection data was faster. In addition, STF‐amended injection solutions arrived faster and to a greater extent in monitoring locations within low‐permeability zones. ERT data showed that the STF injection covered a higher percentage of a two‐dimensional cross section within the injection interval between the injection well and a monitoring well about 3 m away.
Tree Coring as a Complement to Soil Gas Screening to Locate PCE and TCE Source Zones and Hot Spots
Authors: Algreen Mette , Trapp Stefan , Jensen Pernille Rehné , Broholm Mette Martina
Published: March 2018

Preliminary risk assessment for prioritisation of site investigations requires efficient screening to reveal type and level of contamination. The screening methods, tree coring and soil gas sampling were applied and compared at two forested sites contaminated with tetrachloroethylene (PCE) or trichloroethylene (TCE) to evaluate their ability to locate source zones and contaminant hot spots. One test site represented a relatively homogeneous sandy soil and aquifer, and the second a more heterogeneous geology with both sandy and less permeable clay till layers overlying a chalk aquifer. Tree cores from different tree species were sampled and analysed, and compared to soil gas measurements and existing soil gas data. Both methods were found useful as screening tools to locate hot spots of PCE and TCE in the shallow subsurface. Tree coring was found to be particularly beneficial as a complement to soil gas sampling at sites with low permeable soils, and where contamination was located in the capillary rise or shallow groundwater. The shorter time required for tree coring reduced the costs compared to soil gas sampling, but the sensitivity and precision of tree coring were lower. However, this did not affect the feasibility of using tree coring to locate the hot spots. Moreover, a combination of the two methods can help to focus any subsequent investigations like soil or groundwater sampling. The use of tree coring to complement soil gas sampling for pre‐screening is expected to result in higher certainty for revealing hot spots and source zones at contaminated sites.
Land Application of Sulfate Salts for Enhanced Natural Attenuation of Benzene in Groundwater: A Case Study
Authors: Kolhatkar Ravi , Schnobrich Matthew
Published: March 2018

Sulfate reducing conditions are widely observed in groundwater plumes associated with petroleum hydrocarbon releases. This leads to sulfate depletion in groundwater which can limit biodegradation of hydrocarbons (usually benzene, toluene, ethylbenzene, xylenes [BTEX] compounds) and can therefore result in extended timeframes to achieve groundwater cleanup objectives by monitored natural attenuation. Under these conditions, sulfate addition to the subsurface can potentially enhance BTEX biodegradation and facilitate enhanced natural attenuation. However, a delivery approach that enables effective contact with the hydrocarbons and is able to sustain elevated and uniform sulfate concentrations in groundwater remains a key challenge. In this case study, sulfate addition to a groundwater plume containing predominantly benzene by land application of agricultural gypsum and Epsom salt is described. Over 4 years of groundwater monitoring data from key wells subjected to pilot‐scale and site‐wide land application events are presented. These are compared to data from pilot testing employing liquid Epsom salt injections as an alternate sulfate delivery approach. Sulfate land application, sulfate retention within the vadose zone, and periodic infiltration following ongoing precipitation events resulted in elevated sulfate concentrations (>150 mg/L) in groundwater that were sustained over 12 months between application events and stimulated benzene biodegradation as indicated by declines in dissolved benzene concentration, and compound‐specific isotope analysis data for carbon in benzene. Long‐term groundwater benzene concentration reductions were achieved in spite of periodic rebounds resulting from water table fluctuations across the smear zone. Land application of gypsum is a potentially cost‐effective sulfate delivery approach at sites with open, unpaved surfaces, relatively permeable geology, and shallow hydrocarbon impacts. However, more research is needed to understand the fate and persistence of sulfate and to improve the likelihood of success and effectiveness of this delivery approach.
Bioremediation Management Reduces Mass Discharge at a Chlorinated DNAPL Site
Authors: Baldwin Brett R. , Taggart Dora , Chai Yunzhou , Wandor David , Biernacki Anita , L. Sublette Kerry , T. Wilson John , Walecka‐Hutchison Claudia , Coladonato Camillo , Goodwin Bryan
Published: March 2018

Adaptive site management and aggressive bioremediation in the source zone of a complex chlorinated dense nonaqueous phase liquid (DNAPL) site reduced total chlorinated hydrocarbon mass discharge by nearly 80%. Successful anaerobic bioremediation of chlorinated hydrocarbons can be impaired by inadequate concentrations of electron donors, competing electron acceptors, specific inhibitors such as chloroform, and potentially by high contaminant concentrations associated with residual DNAPL. At the study site, the fractured bedrock aquifer was impacted by a mixture of chlorinated solvents and associated daughter products. Concentrations of 1,1,2,2‐tetrachloroethane (1,1,2,2‐TeCA), 1,1,2‐trichloroethane (1,1,2‐TCA), and 1,2‐dichloroethane (1,2‐DCA) were on the order of 100 to 1000 mg/L. Chloroform was present as a co‐contaminant and background sulfate concentrations were approximately 400 mg/L. Following propylene glycol injections, concentrations of organohalide‐respiring bacteria including Dehalococcoides and Dehalogenimonas spp. increased by two to three orders of magnitude across most of the source area. Statistical analysis indicated that reaching volatile fatty acid concentrations greater than 1000 mg/L and depleting sulfate to concentrations less than 50 mg/L were required to achieve a Dehalococcoides concentration greater than the 104 cells/mL recommended for generally effective reductive dechlorination. In a limited area, chloroform concentrations greater than 5 mg/L inhibited growth of Dehalococcoides populations despite the availability of electron donor and otherwise appropriate geochemical conditions. After implementing a groundwater recirculation system targeting the inhibited area, chloroform concentrations decreased permitting significant increases in concentrations of Dehalococcoides and vinyl chloride reductase gene copies.
Overview of Natural Source Zone Depletion: Processes, Controlling Factors, and Composition Change
Authors: Garg Sanjay , Newell Charles J. , Kulkarni Poonam R. , King David C. , Adamson David T. , Renno Maria Irianni , Sale Tom
Published: March 2018

Natural source zone depletion (NSZD) has emerged as a practical alternative for restoration of light non‐aqueous phase liquid (LNAPL) sites that are in the later stages of their remediation lifecycle. Due to significant research, the NSZD conceptual model has evolved dramatically in recent years, and methanogenesis is now accepted as a dominant attenuation process (e.g., Lundegard and Johnson ; Ng et al. ). Most of the methane is generated within the pore space adjacent to LNAPL (Ng et al. ) from where it migrates through the unsaturated zone (e.g., Amos and Mayer ), where it is oxidized. While great progress has been made, there are still some important gaps in our understanding of NSZD. NSZD measurements provide little insight on which constituents are actually degrading; it is unclear which rate‐limiting factors that can be manipulated to increase NSZD rates; and how longevity of the bulk LNAPL and its key constituents can be predicted. Various threads of literature were pursued to shed light on some of the questions listed above. Several processes that may influence NSZD or its measurement were identified: temperature, inhibition from acetate buildup, protozoa predation, presence of electron acceptors, inhibition from volatile hydrocarbons, alkalinity/pH, and the availability of nutrients can all affect methanogenesis rates, while factors such as moisture content and soil type can influence its measurement. The methanogenic process appears to have a sequenced utilization of the constituents or chemical classes present in the LNAPL due to varying thermodynamic feasibility, biodegradability, and effects of inhibition, but the bulk NSZD rate appears to remain quasi‐zero order. A simplified version of the reactive transport model presented by Ng et al. has the potential to be a useful tool for predicting the longevity of key LNAPL constituents or chemical fractions, and of bulk LNAPL, but more work is needed to obtain key input parameters such as chemical classes and their biodegradation rates and any potential inhibitions.
On Methods for In‐Well Nitrate Monitoring Using Optical Sensors
Authors: MacDonald Graeme , Levison Jana , Parker Beth
Published: March 2018

Optical sensors are promising for collecting high resolution in‐well groundwater nitrate monitoring data. Traditional well purging methods are labor intensive, can disturb ambient conditions and yield an unknown blend of groundwater in the samples collected, and obtain samples at a limited temporal resolution (i.e., monthly or seasonally). This study evaluated the Submersible Ultraviolet Nitrate Analyzer (SUNA) for in‐well nitrate monitoring through new applications in shallow overburden and fractured bedrock environments. Results indicated that SUNA nitrate‐N concentration measurements during flow cell testing were strongly correlated (R
2 = 0.99) to purged sample concentrations. Vertical profiling of the water column identified distinct zones having different nitrate‐N concentrations in conventional long‐screened overburden wells and open bedrock boreholes. Real‐time remote monitoring revealed dynamic responses in nitrate‐N concentrations following recharge events. The monitoring platform significantly reduced labor requirements for the large amount of data produced. Practitioners should consider using optical sensors for real‐time monitoring if nitrate concentrations are expected to change rapidly, or if a site's physical constraints make traditional sampling programs challenging. This study demonstrates the feasibility of applying the SUNA in shallow overburden and fractured bedrock environments to obtain reliable data, identifies operational challenges encountered, and discusses the range of insights available to groundwater professionals so they will seek to gather high resolution in‐well monitoring data wherever possible.
Storage and Preservation of Artificial Sweeteners in Groundwater Samples
Authors: Saurette Emily M. , Groza Laura G. , Blowes David W. , Ptacek Carol J.
Published: March 2018

Compound‐specific standardized sampling and storage methods are not available for artificial sweeteners found in groundwater. This study aimed to understand: (1) the appropriate length of storage time for samples containing acesulfame (ACE), sucralose (SUC), saccharin (SAC), and cyclamate (CYC) in simulated groundwater (SGW); (2) conditions of their stability; and (3) which sampling materials are appropriate for sample collection. The evaluated storage conditions included acidification, headspace, exposure to light, and refrigeration; the evaluated sampling materials included steel, stainless steel, aluminum, polyvinyl chloride, polyamide (nylon), polypropylene (PharMed BPT™) tubing, styrene‐ethylene‐butylene co‐polymer (MasterFlex™) tubing, and polytetrafluoroethylene (Teflon™) tubing. All compounds evaluated were stable in storage at 4 °C for 241 d (8 months). Concentrations of artificial sweeteners were consistently within 60% to 120% of original concentrations, except ACE and SAC that were substantially lower under acidified conditions at 25 °C after 241 d. Artificial sweetener concentrations remained nearly constant while in contact with all sampling materials except steel. SEM and TEM images showed oxidation of steel occurred; moreover, removal of all artificial sweetener compounds from aqueous solution had occurred after 289 d. These results suggest artificial sweetener analyses conducted within 14 d of sample collection produce optimal results; however, longer storage times may be acceptable under certain conditions. The results also suggest concentrations of artificial sweeteners in SGW are not affected by contact with typical well casing, sampling, and storage materials, with the exception of steel. The findings from this study will improve the use of artificial sweeteners as tracers in environmental studies.
Novel Well Completions in Small Diameter Coreholes Created Using Portable Rock Drills
Authors: Pierce Amanda A. , Parker Beth L. , Ingleton Robert , Cherry John A.
Published: March 2018

Difficult access conditions have limited techniques for groundwater system characterization and monitoring in bedrock exposed landscapes. This condition is common in the mining industry and resulted in the development of lightweight portable drills. This paper describes how these drills were used at a contaminated site to understand the groundwater flow system by adapting piezometer designs, ensuring effective seals to obtain reliable hydraulic head, hydrochemistry, and contaminant concentrations. Two drilling machines were evaluated: the Shaw Portable Core Drill™ fits in a backpack and can advance continuously cored rock holes, nominal 51 millimeters (mm) diameter, to depths up to approximately 15 meters (m); and the larger Winkie Drill™ requires a two or more people to mobilize and can advance continuously cored holes, nominal 48 mm diameter, to depths of approximately 45 m. The resulting small diameter coreholes were accommodated in the design of each well using a seal created by injecting grout into a semipermeable fabric sleeve. This “fabric sleeve” serves as a means to contain the grout and ensures that the entire annulus above the screen is sealed without loss of grout into the formation, allowing the well to perform as a piezometer. To develop and demonstrate this methodology for groundwater monitoring in bedrock, the two drills were used in drainages located along the slopes of an elevated sandstone outcrop near Los Angeles, California. Unique insights into the groundwater flow system of this bedrock environment, which would otherwise be unattainable, were achieved. This methodology overcomes the accessibility limitations of conventional drilling methods that prevent installation of wells in remote and rugged mountainous terrains.
1,4‐Dioxane Soil Remediation Using Enhanced Soil Vapor Extraction: I. Field Demonstration
Authors: Hinchee Robert E. , Dahlen Paul R. , Johnson Paul C. , Burris David R.
Published: March 2018

1,4‐Dioxane is totally miscible in water, sequestering in vadose pore water that can serve as a source of long‐term groundwater contamination. Although some 1,4‐dioxane is removed by conventional soil vapor extraction (SVE), remediation is typically inefficient. SVE efficiency is hindered by low Henry’s Law constants at ambient temperature and redistribution to vadose pore water if SVE wells pull 1,4‐dioxane vapors across previously clean soil. It was hypothesized that heated air injection and more focused SVE extraction (“Enhanced SVE” or XSVE) could increase the efficiency of 1,4‐dioxane vadose treatment, and this new process was tested at former McClellan Air Force Base, CA. The XSVE system had four peripheral heated air injection wells surrounding a 6.1 m × 6.1 m × 9.1 m deep treatment zone with a central vapor extraction well. After 14 months of operation, soil temperatures reached as high as ~90 °C near the injection wells and the treatment zone was flushed with ~20,000 pore volumes of injected air. Post‐treatment sampling results showed reductions of ~94% in 1,4‐dioxane and ~45% in soil moisture. Given the simplicity of the remediation system components and the promising demonstration test results, XSVE has the potential to be a cost‐effective remediation option for vadose zone soil containing 1,4‐dioxane.
Detection and function of lipopolysaccharide and its purified lipid A after treatment with auxiliary chemical substances and calcium hydroxide dressings used in root canal treatment
Authors: Marinho A. C. S. , To T. T. , Darveau R. P. , Gomes B. P. F. A.
Published: March 2018

Aim

To investigate the influence of auxiliary chemical substances (ACSs) and calcium hydroxide [Ca(OH)2] dressings on lipopolysaccharides (LPS)/lipid A detection and its functional ability in activating Toll‐like receptor 4 (TLR4).

Methodology

Fusobacterium nucleatum pellets were exposed to antimicrobial agents as following: (i) ACS: 5.25%, 2.5% and 1% sodium hypochlorite solutions (NaOCl), 2% chlorhexidine (CHX) (gel and solution) and 17% ethylenediaminetetraacetic acid (EDTA); (ii) intracanal medicament: Ca(OH)2 paste for various periods (1 h, 24 h, 7 days, 14 days and 30 days); (iii) combination of substances: (a) 2.5% NaOCl (1 h), followed by 17% EDTA (3 min) and Ca(OH)2 (7 days); (b) 2% CHX (1 h), afterwards, 17% EDTA (3 min) followed by Ca(OH)2 (7 days). Saline solution was the control. Samples were submitted to LPS isolation and lipid A purification. Lipid A peaks were assessed by matrix‐assisted laser desorption ionization time‐of‐flight mass spectrom (MALDI‐TOF MS) whilst LPS bands by SDS–PAGE separation and silver staining. TLR4 activation determined LPS function activities. Statistical comparisons were carried out using one‐way anova with Tukey–Kramer post‐hoc tests at the 5% significance level.

Results

Matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry analysis of control lipid A demonstrated the ion cluster at mass/charge (m/z) 1882 and an intense band in SDS–PAGE followed by silver staining of control LPS. In parallel, LPS control induced a robust TLR4 activation when compared to ACS (P ≤ .001). 5.25% NaOCl treatment led to the absence of lipid A peaks and LPS bands, whilst no changes occurred to lipid A/LPS after treatment with others ACS. Concomitantly, 5.25% NaOCl‐treated LPS did not activate TLR4 (P < .0001). As for Ca(OH)2, lipid A was not detected by MALDI‐TOF nor by gel electrophoresis within 24 h. LPS treated with Ca(OH)2 was a weak TLR4 activator (P < .0001). From 24 h onwards, no significant differences were found amongst the time periods tested (P > 0.05). The addition of Ca(OH)2 for 7 days to cells treated either with 2.5% NaOCl or 2% CHX led to the absence of lipid A peaks and LPS bands, leading to a lower activation of TLR4.

Conclusion

5.25% NaOCl and Ca(OH)2 dressings from 24 h onwards were able to induce both, loss of lipid A peaks and no detection of LPS bands, rendering a diminished immunostimulatory activity through TLR4.
RESIDUAL WAGE DISPERSION WITH EFFICIENCY WAGES
Authors: Piyapromdee Suphanit
Published: March 2018

This article extends a classic on‐the‐job search model of homogeneous workers and firms by introducing a shirking problem. Workers choose their effort levels and search on the job. Firms elicit effort through wages and monitoring; an inverse relationship between wages and monitoring rates is derived. Wages play a dual role by allocating labor supply and motivating employee effort. This gives rise to an equilibrium wage distribution that contrasts with existing literature. In particular, I show that a hump‐shaped and positively skewed wage distribution, as observed empirically, can be derived even when firms and workers are, respectively, identical.
THE EFFECT OF AN EARLY CAREER RECESSION ON SCHOOLING AND LIFETIME WELFARE
Authors: Guo Naijia
Published: March 2018

This article evaluates the lifetime welfare and labor market consequences of experiencing a recession during youth, using a directed search equilibrium model with heterogeneous agents and aggregate shocks. In particular, the model allows for endogenous schooling decisions over the business cycles. The counterfactual analysis shows that experiencing the 1981–82 recession in youth causes a 1.6%–2.3% loss in lifetime welfare. Endogenizing the schooling decision avoids overestimation of welfare loss because of the selection effect and the human capital effect. I also decompose lifetime wage changes into different channels: changes from schooling, work experience, and job mobility.
Evidence‐based nursing outputs and hot spot analysis of the last 5 years in mainland China: Results of a bibliometric analysis
Authors: Zhao Junqiang , Liu Xinjuan , Zhang Wei , Xing Yana , Cho Sang Wouk , Hao Yufang
Published: March 2018

Background

Evidence‐based nursing has been highlighted and highly developed in recent decades in mainland China. Nevertheless, little is known about its overall development.

Aims

To gain insights on the overall development of evidence‐based nursing in the most recent 5 years and to inform future evidence‐based nursing research in mainland China.

Method

Four Chinese and four English databases were searched with the search terms “evidence‐based practice,” “nurse or nursing,” and “China or Chinese” from 2012 to 2016. Bibliometric and co‐word cluster analysis were conducted with the final included publications.

Results

A total of 9036 papers published by 13 808 authors in 606 journals were included. Publication numbers were increasing. None of the top ten journals publishing evidence‐based nursing papers were core nursing journals. The research hot spots on evidence‐based nursing in the recent five years were cardiovascular disease, mental health, and complication prevention. However, little attention has been paid to education for evidence‐based nursing.

Conclusion

Evidence‐based nursing has penetrated into various nursing branches in mainland China and become a well‐recognized and relatively mature research domain. More importance should be attached to the study design, methodological, and reporting quality of evidence‐based nursing projects.
The educational preparation of nurses in a developing economy and patient mortality
Authors: Mahfoud Z. R. , Gkantaras I. , Topping A. E. , Cannaby A. M. , Foreman B. , Watson R. , Thompson D. R. , Gray R.
Published: March 2018

Background

Most studies have reported that higher levels (baccalaureate degree) of educational attainment by nurses are associated with lower levels of patient mortality. Researchers working in developed economies (e.g. North America and Europe) have almost exclusively conducted these studies. The value of baccalaureate nurse education has not been tested in countries with a developing economy.

Method

A retrospective observational study conducted in seven hospitals. Patient mortality was the main outcome of interest. Anonymized data were extracted from nurses and patients from two different administrative sources and linked using the staff identification number that exists in both systems. We used bivariate logistic regression models to test the association between mortality and the educational attainment of the admitting nurse (responsible for assessment and care planning).

Results

Data were extracted for 11 918 (12, 830 admissions) patients and 7415 nurses over the first 6 months of 2015. The majority of nurses were educated in South Asia and just over half were educated to at least bachelor degree level. After adjusting for confounding and clustering, nurse education was not found to be associated with mortality.

Implications for nursing and health policy

Our observations may suggest that in a developing economy, the academic level of nurses’ education is not associated with a reduction in patient mortality. Findings should be interpreted with considerable caution but do challenge widely held assumptions about the value of baccalaureate‐prepared nurses. Further research focused on nursing education in developing economies is required to inform health policy and planning.
Trends of hospitalizations for syncope/collapse in the United States from 2004 to 2013–An analysis of national inpatient sample
Authors: Anand Vidhu , Benditt David G. , Adkisson Wayne O. , Garg Sushil , George Stephen A. , Adabag Selcuk
Published: March 2018

Introduction

Syncope/collapse is a common reason for emergency department visits, and approximately 30–40% of these individuals are hospitalized. We examined changes in hospitalization rates, in‐hospital mortality, and cost of syncope/collapse‐related hospital care in the United States from 2004 to 2013.

Methods

We used the US Nationwide Inpatient Sample (NIS) from 2004 to 2013 to identify syncope/collapse‐related hospitalizations using ICD‐9, code 780.2, as the principal discharge diagnosis. Data are presented as mean ± SEM.

Results

From 2004 to 2013, there was a 42% reduction in hospitalizations with a principal discharge diagnosis of syncope/collapse from 54,259 (national estimate 253,591) in 2004 to 31,427 (national estimate 156,820) in 2013 (P < 0.0001). The mean length of hospital stays decreased (2.88 ± 0.04 days in 2004 vs. 2.54 ± 0.02 in 2013; P < 0.0001), while in‐hospital mortality did not change (0.28% in 2004 vs. 0.18% in 2013; P  =  0.12). However, mean charges (inflation adjusted) for syncope/collapse‐related hospitalization increased by 43.6% from $17,514 in 2004 to $25,160 in 2013 (P < 0.0001). The rates of implantation of permanent pacemakers and implantable cardioverter defibrillator remained low during these hospitalizations, and decreased over time (P for both < 0.0001).

Conclusions

Hospitalization rates for syncope/collapse have decreased significantly in the US from 2004 to 2013. Despite a modest reduction in length of stay, the cost of syncope/collapse‐related hospital care has increased.