bluuebunny/crossref_metadata_2025 huggingface dataset:
High climate velocity and population fragmentation may constrain climate‐driven range shift of the key habitat former Fucus vesiculosus
Authors: Jonsson Per R. , Kotta Jonne , Andersson Helén C. , Herkül Kristjan , Virtanen Elina , Sandman Antonia Nyström , Johannesson Kerstin
Published: March 2018

Aim

The Baltic Sea forms a unique regional sea with its salinity gradient ranging from marine to nearly freshwater conditions. It is one of the most environmentally impacted brackish seas worldwide, and the low biodiversity makes it particularly sensitive to anthropogenic pressures including climate change. We applied a novel combination of models to predict the fate of one of the dominant foundation species in the Baltic Sea, the bladder wrack Fucus vesiculosus.

Location

The Baltic Sea.

Methods

We used a species distribution model to predict climate change‐induced displacement of F. vesiculosus and combined these projections with a biophysical model of dispersal and connectivity to explore whether the dispersal rate of locally adapted genotypes may match estimated climate velocities to recolonize the receding salinity gradient. In addition, we used a population dynamic model to assess possible effects of habitat fragmentation.

Results

The species distribution model showed that the habitat of F. vesiculosus is expected to dramatically shrink, mainly caused by the predicted reduction of salinity. In addition, the dispersal rate of locally adapted genotypes may not keep pace with estimated climate velocities rendering the recolonization of the receding salinity gradient more difficult. A simplistic model of population dynamics also indicated that the risk of local extinction may increase due to future habitat fragmentation.

Main conclusions

Results point to a significant risk of locally adapted genotypes being unable to shift their ranges sufficiently fast considering the restricted dispersal and long generation time. The worst scenario is that F. vesiculosus may disappear from large parts of the Baltic Sea before the end of this century with large effects on the biodiversity and ecosystem functioning. We finally discuss how to reduce this risk through conservation actions, including assisted colonization and assisted evolution.
Species‐poor and low‐lying sites are more ecologically unique in a hyperdiverse Amazon region: Evidence from multiple taxonomic groups
Authors: Landeiro Victor Lemes , Franz Bárbarah , Heino Jani , Siqueira Tadeu , Bini Luis Mauricio
Published: March 2018

Aim

We analysed beta‐diversity patterns of various biological groups simultaneously, from the perspective of site ecological uniqueness. We also investigated whether ecological uniqueness variation could be explained by variations in environmental conditions and spatial variables.

Data

Central Amazonia.

Methods

We estimated the total beta diversity and ecological uniqueness for 14 biological groups, including plants and animals, sampled at the same sites on a mesoscale in central Amazonia, Brazil. The uniqueness values for all biological groups were combined in a single matrix (multi‐taxa matrix of site uniqueness), which was then used as a response variable matrix in a partial redundancy analysis. We also investigated differences in the uniqueness patterns between plant and animal groups.

Results

In general, plants showed higher total beta diversity than animals. For plants, uniqueness was explained mainly by environmental conditions, while for animals, uniqueness was also related to spatial variables. Although variation in uniqueness was mainly related to soil clay content, it is difficult to determine a single major environmental variable underlying the variation in uniqueness because the topographical gradient influences many of them, including soil clay content.

Main Conclusion

The uniqueness values were higher in low‐lying areas, indicating that near‐stream sites were more ecologically unique. Despite the lower number of species in the lowlands, their unique biota contributed strongly to the maintenance of the total beta diversity of the area. This finding should be considered in conservation plans that aim to represent and preserve the regional biota. Our approach proved to be useful to analyse and compare the ecological uniqueness of multiple taxa.
Role of bicarbonate supplementation on urine uric acid crystals and diabetic tubulopathy in adults with type 1 diabetes
Authors: Bjornstad Petter , Maahs David M. , Roncal Carlos A. , Snell‐Bergeon Janet K. , Shah Viral N. , Milagres Tamara , Ellis Samuel L. , Hatch Matthew , Chung Linh T. , Rewers Marian J. , Garg Satish , Cherney David Z. , Pyle Laura , Nadeau Kristen J. , Johnson Richard J.
Published: March 2018

Uricosuria and crystallization are increasingly recognized risk factors for diabetic tubulopathy. This pilot clinical trial aimed to determine the acute effect of urinary alkalinization using oral sodium bicarbonate (NaHCO3) on UA crystals in adults with type 1 diabetes (T1D). Adults with T1D, ages 18 to 65 years (n = 45, 60% female, HbA1c, 7.5 ± 1.2%, 20.2 ± 9.3 years duration) without chronic kidney disease (eGFR ≥60 mL/min/1.73 m2 and albumin‐to‐creatinine ratio < 30 mg/g) received 2 doses of 1950 mg oral NaHCO3 over 24 hours. Fasting urine and serum were collected pre‐ and post‐intervention. UA crystals were identified under polarized microscopy. Urine measurements included: osmolality, pH, UA, creatinine and kidney injury molecule‐1 (KIM‐1).

NaHCO3 therapy increased mean ± SD urine pH from 6.1 ± 0.7 to 6.5 ± 0.7 (P < .0001). Prior to therapy, 31.0% of participants had UA crystals vs 6.7% post therapy (P = .005). Change in urine pH inversely correlated with change in urine KIM‐1 (r:–0.51, P = .0003). In addition, change in urine UA over 24 hours correlated with change in urine KIM‐1 (r:0.37, P = .01). In conclusion, oral NaHCO3 normalized urine pH and decreased UA crystals, and may hold promise as an inexpensive and safe tubulo‐protective intervention in individuals with T1D.
Coase Lecture – The Glass Ceiling
Authors: Bertrand Marianne
Published: March 2018

Despite decades of progress, women remain underrepresented in the upper part of the earnings distribution. We review the recent research trying to explain this phenomenon. After briefly revisiting gender differences in education, we turn our attention to a body of work that has argued that gender differences in psychological attributes are holding back women's earnings. We then review another active area of research focused on the challenges that women may face when trying to juggle competing demands on their time in the workplace and the home, particularly when the home includes children. We discuss recent work documenting women's greater demand for flexibility in the workplace, as well as work measuring the labour market penalties associated with such demand for flexibility, particularly in the higher paying occupations in the economy. We highlight possible countervailing forces (both at work and at home) that may explain why these work–family considerations may remain highly relevant to today's glass ceiling despite reduced time spent in non‐market work and a trend towards a more equal division of non‐market work between men and women. Finally, we discuss the role that public policy and human resource practices may play in adding more cracks to the glass ceiling.
MEASUREMENT ERROR IN MACROECONOMIC DATA AND ECONOMICS RESEARCH: DATA REVISIONS, GROSS DOMESTIC PRODUCT, AND GROSS DOMESTIC INCOME
Authors: Chang Andrew C. , Li Phillip
Published: March 2018

We use a preanalysis plan to analyze the effect of measurement error on economics research using the fact that the Bureau of Economic Analysis both revises its gross domestic product (GDP) data and also publishes a second, theoretically identical estimate of U.S. output that only differs from GDP due to measurement error: gross domestic income (GDI). Using a sample of 23 models published in top economics journals, we find that reestimating models using revised GDP always gives the same qualitative result as the original publication. Estimating models using GDI instead of GDP gives a different qualitative result for three of 23 models (13%). (JEL C80, C82, E01)
Producing offspring in Armadillidium vulgare: Effects of genetic diversity and inbreeding
Authors: Durand Sylvine , Loiseau Vincent , Prigot Cybèle , Braquart‐Varnier Christine , Beltran‐Bech Sophie
Published: March 2018

Genetic diversity is known to be correlated to fitness traits, and inbred individuals often display lower values for life history traits. In this study, we attempt to quantify how inbreeding affects such traits in the terrestrial isopod Armadillidium vulgare by performing inbred and non‐inbred crosses under laboratory conditions. We estimated genetic characteristics of parents and offspring, and related them to fecundity and fertility measures, as well as offspring growth and survival. Our study shows that a decrease in offspring number might result from mortality around birth, but not to changes in fecundity, fertilization rate, or developmental failure between inbred and non‐inbred crosses. More heterozygous females tended to be bigger and had a higher fecundity, which could have implications in mate choice. No effect of inbreeding was detected on offspring growth and survival. These results can be related to previously observed effects of genetic characteristics on mating strategies in A. vulgare, and could shed light on mechanisms of inbreeding avoidance in this species.
Innovation in dental education: The “On‐the‐Fly” approach to simultaneous development, implementation and evidence collection
Authors: de Boer I. R. , Bakker D. R. , Serrano C. M. , Koopman P. , Wesselink P. R. , Vervoorn J. M.
Published: March 2018

Introduction

This study outlines an approach for education innovation and addresses the ambivalence between evidence‐based and non‐evidence‐based conditions. The “on‐the‐fly” approach was described as involving implementation during the development of an innovation for dental education.

Materials and Methods

The process of designing and implementing cutting‐edge technology of the MOOG Simodont Dental Trainer (DT) whilst systematically collecting evidence illustrates the “on‐the‐fly” approach.

Results

Using the “on‐the‐fly” approach for developing, implementing and collecting evidence simultaneously in an academic environment appears feasible in serving both the professionals, users and developers and system designers. During the implementation of the new technology, growing evidence stepwise strengthened its position; therefore, showing stakeholders that evidence was used to improve the technology seemed to support and increase acceptance of the new technology.

Conclusions

When pioneering an innovative technology in a specialty field, the development stage often precedes evidence for its effectiveness. Consciously choosing the “on‐the‐fly” approach clarifies to stakeholders in advance about the lack of evidence in an innovation and the need of their support to collect such evidence for improvement and in order to facilitate implementation.
Rubric system for evaluation of crown preparation performed by dental students
Authors: Habib S. R.
Published: March 2018

Objective

This study aimed to investigate the use of an analytic rubric system for the evaluation of all‐ceramic crown preparation on the right maxillary central incisor performed by the dental students.

Materials and Methods

Seventy‐two‐third‐year students and 8 faculty members from prosthodontics participated in this double‐blind study. The students prepared an ivorine tooth # 11 for all‐ceramic crown. The students were given clear instructions regarding the all‐ceramic crown preparation and informed about the criteria for the assessment of the preparation. An analytic rubric based on 10‐point scale for assessment of various preparation parameters was used by the 8 examiners. Descriptive statistics, ANOVA and post hoc Tukey tests were used for statistical analysis.

Results

One‐way analysis of variance indicated significance amongst the examiners for all the parameters except for time management. The overall mean scoring by examiners was 7.60 ± 1.18, with highest and lowest mean scores for Examiner 1 (8.02 ± 1.06) and Examiner 4 (6.82 ± 1.50), respectively. The highest number of interexaminer variation (difference) in scoring was found for two plane reduction, and the least difference amongst the examiners was observed for finishing of margins and walls of the preparation. Examiner 4 had the highest number of significant difference with the rest of the examiners. The students scored least marks in axial reduction (56.33%) and preservation of adjacent teeth (66.9%).

Conclusions

Criteria‐based assessment using analytic rubric for crown preparations in pre‐clinical fixed prosthodontics is an effective tool for finding the errors/weak areas of dental students.
Neural and behavioral effects of subordinate‐level training of novel objects across manipulations of color and spatial frequency
Authors: Jones Travis , Hadley Hillary , Cataldo Andrea M. , Arnold Erik , Curran Tim , Tanaka James W. , Scott Lisa S.
Published: March 2018

Perceptual expertise is marked by subordinate‐level recognition of objects in the expert domain. In this study, participants learned one family of full‐color, artificial objects at the subordinate (species) level and another family at the basic (family) level. Discrimination of trained and untrained exemplars was tested before and after training across several image manipulations [full‐color, grayscale, low spatial frequency (LSF) and high spatial frequency (HSF)] while event‐related potentials (ERPs) were recorded. Regardless of image manipulation, discrimination (indexed by d’) of trained and of untrained exemplars was enhanced after subordinate‐level training, but not after basic‐level training. Enhanced discrimination after subordinate‐level training generalized to untrained exemplars and to grayscale images and images in which LSF or HSF information was removed. After training, the N170 and N250, recorded over occipital and occipitotemporal brain regions, were both more enhanced after subordinate‐level training than after basic‐level training. However, the topographic distribution of enhanced responses differed across components. The N170 latency predicted reaction time after both basic‐level training and subordinate‐level training, highlighting an association between behavioral and neural responses. These findings further elucidate the role of the N170 and N250 as ERP indices of subordinate‐level expert object processing and demonstrate how low‐level manipulations of color and spatial frequency impact behavior and the N170 and N250 components independent of training or expertise.
Contrast coding in the primary visual cortex depends on temporal contexts
Authors: Dai Ji , Wang Yi
Published: March 2018

Contrast response function in the primary visual cortex (V1) has long been described as following a sigmoid curve. However, this is mainly based on measuring neural responses to drifting contrast grating in a stable stimulation, a model that does not consider the effects of motion or length of stimulus presentation. During natural viewing, the visual system can obtain sufficient information for identifying the shapes defined by contrast from a single glance; acquiring greater knowledge of the neuronal response properties to contrast in such a short timescale is necessary to understand the underlying mechanisms. We investigated responses of cat V1 neurons to contrast presented by static grating for 40 ms without pause compared to drifting grating presented continuously for 2000 ms. The neuronal response to transiently presented contrast could be well described by a linear function. Further examination of the effects of motion and presentation duration on contrast responses demonstrated that motion increased response sensitivity in the low‐contrast range, while brief presentation increased response sensitivity in the high‐contrast range. Motion and prolonged presentation (adaptation) together resulted in an asymptotic sigmoid curve with a saturation response in the high‐contrast range. These results suggest that motion mainly enhance the neural response sensitivity to low‐contrast objects, while short and rapid presentation mainly enhance the neural sensitivity to high‐contrast stimulus. Our findings indicate that multiple factors influence the properties of contrast response functions, suggesting that V1 neuron contrast coding is flexible and depends on the temporal contexts.
Dermal fibroblasts can activate matrix metalloproteinase‐1 independent of keratinocytes via plasmin in a 3D collagen model
Authors: Sonoki Aska , Okano Yuri , Yoshitake Yuichiro
Published: March 2018

Photoaging of the skin is marked by obvious wrinkles and mainly depends on degradation of the extracellular matrix (ECM) in the dermis. Matrix metalloproteinase (MMP)‐1 is one of the most important factors involved in degradation of the ECM; however, its mechanism of activation is not fully understood. It has been thought that MMP‐1 is expressed by dermal fibroblasts as an inactive precursor protein that is activated by proteinases produced by keratinocytes in the epidermis. In this study, we constructed a 3D model of the dermis using collagen‐embedded fibroblasts with or without ultraviolet (UV)‐A exposure to mimic photoaging in the dermis. Collagen lattices embedded with UV‐A‐irradiated fibroblasts miniaturized and collagen was degraded to a greater extent than collagen lattices embedded with non‐irradiated fibroblasts. The results demonstrate that fibroblasts in this 3D model express activated MMP‐1 in the absence of keratinocytes. Moreover, the results confirm that activation of MMP‐1 depends on increased plasmin activity in this model and lattice miniaturization was inhibited by the plasmin inhibitor tranexamic acid. Our results suggest that plasmin acts as an activator of MMP‐1 and the inhibition of plasmin prevents collagen degradation.
SLAM family member 8 is involved in oncogenic KIT‐mediated signalling in human mastocytosis
Authors: Sugimoto Akihiko , Kataoka Tatsuki R. , Ueshima Chiyuki , Takei Yusuke , Kitamura Kyohei , Hirata Masahiro , Nomura Takashi , Haga Hironori
Published: March 2018

The signalling lymphocytic activation molecule family member 8 (SLAMF8)/CD353 is a member of the CD2 family of proteins. Its ligand has not been identified. SLAMF8 is expressed by macrophages and suppresses cellular functions. No study has yet explored SLAMF8 expression or function in human mastocytosis, which features oncogenic KIT‐mediated proliferation of human mast cells. SLAMF8 protein was expressed in human mastocytosis cells, immunohistochemically. SLAMF8 expression was also evident in the human mast cell lines, HMC1.2 (expressing oncogenic KIT) and LAD2 (expressing wild‐type KIT) cells. SLAMF8 knock‐down significantly reduced the KIT‐mediated growth of HMC1.2 cells but not that of LAD2 cells. SLAMF8 knock‐down HMC1.2 cells exhibited significant attenuation of SHP‐2 activation and oncogenic KIT‐mediated RAS‐RAF‐ERK signalling. An interaction between SLAMF8 and SHP‐2 was confirmed in HMC1.2 cells and all pathological mastocytosis specimens examined (19 of 19 cases, 100%). Thus, SLAMF8 is involved in oncogenic KIT‐mediated RAS‐RAF‐ERK signalling and the subsequent growth of human neoplastic mast cells mediated by SHP‐2. SLAMF8 is a possible therapeutic target in human mastocytosis patients.
An ice‐binding and tandem beta‐sandwich domain‐containing protein in Shewanella frigidimarina is a potential new type of ice adhesin
Authors: Vance Tyler D.R. , Graham Laurie A. , Davies Peter L.
Published: March 2018

Out of the dozen different ice‐binding protein (IBP) structures known, the DUF3494 domain is the most widespread, having been passed many times between prokaryotic and eukaryotic microorganisms by horizontal gene transfer. This ~25‐kDa β‐solenoid domain with an adjacent parallel α‐helix is most commonly associated with an N‐terminal secretory signal peptide. However, examples of the DUF3494 domain preceded by tandem Bacterial Immunoglobulin‐like (BIg) domains are sometimes found, though uncharacterized. Here, we present one such protein (SfIBP_1) from the Antarctic bacterium Shewanella frigidimarina. We have confirmed and characterized the ice‐binding activity of its ice‐binding domain using thermal hysteresis measurements, fluorescent ice plane affinity analysis, and ice recrystallization inhibition assays. X‐ray crystallography was used to solve the structure of the SfIBP_1 ice‐binding domain, to further characterize its ice‐binding surface and unique method of stabilizing or ‘capping’ the ends of the solenoid structure. The latter is formed from the interaction of two loops mediated by a combination of tandem prolines and electrostatic interactions. Furthermore, given their domain architecture and membrane association, we propose that these BIg‐containing DUF3494 IBPs serve as ice‐binding adhesion proteins that are capable of adsorbing their host bacterium onto ice.

Database

Submitted new structure to the Protein Data Bank (PDB: 6BG8).
Differential effects of Vav‐promoter‐driven overexpression of BCLX and BFL1 on lymphocyte survival and B cell lymphomagenesis
Authors: Tuzlak Selma , Haschka Manuel D. , Mokina Anna‐Maria , Rülicke Thomas , Cory Suzanne , Labi Verena , Villunger Andreas
Published: March 2018

Overexpression of BCLX and BFL1/A1 has been reported in various human malignancies and is associated with poor prognosis and drug resistance, identifying these prosurvival BCL2 family members as putative drug targets. We have generated transgenic mice that express human BFL1 or human BCLX protein throughout the haematopoietic system under the control of the Vav gene promoter. Haematopoiesis is normal in both the Vav‐BFL1 and Vav‐BCLX transgenic (TG) mice and susceptibility to spontaneous haematopoietic malignancies is not increased. Lymphoid cells from Vav‐BCLX TG mice exhibit increased resistance to apoptosis in vitro while most blood cell types form Vav‐BFL1 TG mice were poorly protected. Both transgenes significantly accelerated lymphomagenesis in Eμ‐MYC TG mice and, surprisingly, the Vav‐BFL1 transgene was the more potent. Unexpectedly, expression of transgenic BFL1 RNA and protein is significantly elevated in B lymphoid cells of Vav‐BFL1/Eμ‐MYC double‐transgenic compared to Vav‐BFL1 mice, even during the preleukaemic phase, providing a rationale for the potent synergy. In contrast, Vav‐BCLX expression was not notably different. These mouse models of BFL1 and BCLX overexpression in lymphomas should be useful tools for the testing the efficacy of novel human BFL1‐ and BCLX‐specific inhibitors.
Using remote sensing indicators to investigate the association of landings with fronts: Application to the Alboran Sea (western Mediterranean Sea)
Authors: Brigolin D. , Girardi P. , Miller P. I. , Xu W. , Nachite D. , Zucchetta M. , Pranovi F.
Published: March 2018

This study examined links between the variability of coastal front features and composition of fishery landings. Satellite‐derived sea surface temperature data allowed the detection of thermal fronts and calculation of front metrics that account for gradient, persistency, and vicinity. Landings data were clustered by functional group (according to habitat use, size, morphology), and trophic level (TL). Three independent time series analyses, based on two different classes of statistical methodologies, were carried out: (i) correlation analysis performed on species aggregated by functional groups, and (ii) compositional analysis performed on the top five species landed and on species aggregated by trophic level. Analyses were carried out for the Moroccan coast of the Alboran Sea (western Mediterranean Sea). Results of the proposed type of application were discussed with respect to their potential for improving scientific knowledge and management of fisheries in data‐poor areas. Pelagic landings were associated with front indicators in two‐thirds of tested cases. The results demonstrated a markedly different association between landings and front features in the Nador fishing zone, relative to M'diq and Al Hoceima. Improved performance of the front gradient and persistence indicator was detected, with respect to the front gradient only for flatfish and demersal landings. Compositional data regression outlined a different role for Sardina pilchardus and Trachurus trachurus in the Al Hoceima and M'diq landings, and in the latter case the dominance of these two species in the landings seemed to respond to the front density indicator. A decreasing trend in TL > 3.5 landings was detected with increasing front distance.
Climate change likely to reduce orchid bee abundance even in climatic suitable sites
Authors: Faleiro Frederico Valtuille , Nemésio André , Loyola Rafael
Published: March 2018

Studies have tested whether model predictions based on species’ occurrence can predict the spatial pattern of population abundance. The relationship between predicted environmental suitability and population abundance varies in shape, strength and predictive power. However, little attention has been paid to the congruence in predictions of different models fed with occurrence or abundance data, in particular when comparing metrics of climate change impact. Here, we used the ecological niche modeling fit with presence–absence and abundance data of orchid bees to predict the effect of climate change on species and assembly level distribution patterns. In addition, we assessed whether predictions of presence–absence models can be used as a proxy to abundance patterns. We obtained georeferenced abundance data of orchid bees (Hymenoptera: Apidae: Euglossina) in the Brazilian Atlantic Forest. Sampling method consisted in attracting male orchid bees to baits of at least five different aromatic compounds and collecting the individuals with entomological nets or bait traps. We limited abundance data to those obtained by similar standard sampling protocol to avoid bias in abundance estimation. We used boosted regression trees to model ecological niches and project them into six climate models and two Representative Concentration Pathways. We found that models based on species occurrences worked as a proxy for changes in population abundance when the output of the models were continuous; results were very different when outputs were discretized to binary predictions. We found an overall trend of diminishing abundance in the future, but a clear retention of climatically suitable sites too. Furthermore, geographic distance to gained climatic suitable areas can be very short, although it embraces great variation. Changes in species richness and turnover would be concentrated in western and southern Atlantic Forest. Our findings offer support to the ongoing debate of suitability–abundance models and can be used to support spatial conservation prioritization schemes and species triage in Atlantic Forest.
A comparison of milk yields and methane production from three contrasting high‐yielding dairy cattle feeding regimes: Cut‐and‐carry, partial grazing and total mixed ration
Authors: Cameron L. , Chagunda M. G. G. , Roberts D. J. , Lee M. A.
Published: March 2018

There have been reductions in grazing cattle and corresponding increases in mixed diets across many regions. Mixed diets consist of silage, grains, legumes and other herbaceous plants (termed total mixed ration, TMR). TMR has been associated with increased milk yields but has also been linked to increased enteric methane production. We measured milk yields and methane production from high‐yielding Holstein‐Friesian cattle after substituting 29%–36% of a TMR diet with grass. Two feeding treatments were compared with a diet of TMR: grass grazed at pasture and grass cut in the field and delivered to housed cattle (termed cut‐and‐carry). Each feeding treatment was fed to 15 cattle, and the experiment was conducted in South‐west Scotland. Using a laser methane detector, we measured a twofold and fourfold decline in enteric methane production for the cut‐and‐carry and grazing groups, respectively, when the animals consumed grass. TMR was consumed by both grass‐fed groups overnight, so daily values were adjusted to include elevated methane production during this period. This revealed that methane production for the cut‐and‐carry and grazing groups was 17% and 39% lower than for the TMR‐fed group respectively. Milk yields were maintained for all three groups, and the efficiency of milk production per unit of methane was substantially greater for the two grass‐fed groups. A shift away from exclusively feeding TMR by adding fresh grass to the diets of cattle could contribute to meeting emissions targets and could also represent an economically sustainable climate change mitigation strategy.
Natural history of gastric cancer from a retrospective review of endoscopic images of older patients with interval gastric cancer
Authors: Iida Tomoya , Yamashita Kentaro , Ohwada Sae , Ohkubo Yosuke , Hirano Takehiro , Miyake Takakazu , Onodera Kei , Kubo Toshiyuki , Yamano Hiroo , Nakase Hiroshi
Published: March 2018

Aim

Interval gastric cancers (IGC) are defined as those diagnosed after negative results of endoscopy carried out within the past 10 years. We aimed to investigate the characteristics of IGC and the natural history of gastric cancer (GC) from a retrospective view of endoscopic images of older patients with IGC.

Methods

We retrospectively reviewed endoscopic images of 240 patients with GC who were aged >60 years. We compared past endoscopic images with newer ones, in which GC was diagnosed. IGC were classified into two categories: missed cancers and new cancers.

Results

Of the 240 patients with GC, 32 had past endoscopic images that qualified for a precise review. A total of 14 cases involved new cancers, whereas 18 involved missed cancers. Most of the IGC were stage I for at least 2 years; however, a small subset was unresectable at >2 years after a negative endoscopy. Furthermore, the rate of endoscopic treatment was significantly higher for IGC compared with that for non‐IGC.

Conclusions

In people aged >60 years, most IGC remain in an early stage for at least 2 years; however, at >2 years after a negative endoscopy, some are unresectable. These results suggest that most early‐stage GC will not develop into advanced cancers within 2 years; thus, a 2‐year interval might be within the permissible range for patients with negative endoscopy results for any lesions. Geriatr Gerontol Int 2018; 18: 997–1002
Effects of Glacial Sediment Type and Land Use on Nitrate Patterns in Groundwater
Authors: Best Anna , Arnaud Emmanuelle , Parker Beth , Aravena Ramon , Dunfield Kari
Published: March 2018

Growing population centers such as those in southern Ontario rely on fractured bedrock aquifers for drinking water. A threat to these aquifers is posed by surficial nonpoint‐source pollution infiltrating with rainwater and moving through the overlying Quaternary glacial deposits. Investigation of local unconsolidated sediments, and the factors affecting contaminant transport through these, is needed to assess risks to the quality of underlying groundwater resources. In this study, sites with a variety of agricultural land management practices and glacial geologic settings were investigated by employing high‐resolution data collection methods. Geologic data from continuous sediment cores were combined with depth‐discrete hydrogeologic and geochemical parameter measurements using high‐resolution multilevel monitoring wells. Within a relatively small geographic area with three distinct glacially derived sediment types, the three sites exhibited greatly disparate vulnerability to nitrate contamination. The geologic setting, including surface topography and architecture and heterogeneity of sediment types at depth, influenced groundwater flow paths and water geochemistry, and subsequently, nitrate distribution. Although management practices influence the quantity of pollutants leaching to groundwater resources, the physical and chemical properties of the subsurface related to the geologic setting ultimately determine the persistence or attenuation of nitrate, and therefore become important to characterize when evaluating best nutrient and waste management practices.
Challenges and a Strategy for Agricultural BMP Monitoring and Remediation of Nitrate Contamination in Unconsolidated Aquifers
Authors: Rudolph D.L. , Devlin J.F. , Bekeris L.
Published: March 2018

Nitrate in groundwater and surface water is among the most common contamination problems in the world. Efforts to reduce the loss of excess nutrients at the regional scale currently focus on Best Management Practices (BMPs) designed to facilitate the optimal use of fertilizers, adjusted for specific site conditions. Performance monitoring of regional BMPs has proven to be problematic owing to the large areal scales, the inherent heterogeneity of nutrient mobility on landscapes and in the subsurface, and the extended time lag between implementation and overall improvements in groundwater quality. In order to shorten the time for useful assessments of progress and for the beneficial results to be realized, a strategy is proposed here with specific application to unconsolidated granular aquifers. First, a novel approach for quantifying BMP performance in the short term is demonstrated involving the monitoring of transient nitrate storage in the unsaturated zone. Secondly, a temporary remediation method based on in situ denitrification is implemented for reducing nitrate levels in public supply wells in the interim period until the full influence of the regional nutrient management BMPs is realized. The remediation approach incorporates a passive component that necessitates enhanced site characterization methods including high definition assessments of aquifer properties and groundwater velocity. The preliminary findings from a series of field investigations conducted between 2004 and 2011 at a site in southern Ontario indicate that this combined two‐step strategy may be capable of providing short‐term quantifiable evidence of BMP performance and also of attenuating nitrate to desirable levels during the time lag period between implementation of the BMPs and the arrival of their desired beneficial effects on the quality of public well water supplies. This may avoid the need to construct permanent above‐ground water treatment facilities that could eventually become redundant.
Review of Abiotic Degradation of Chlorinated Solvents by Reactive Iron Minerals in Aquifers
Authors: He Y. T. , Wilson J. T. , Su C. , Wilkin R. T.
Published: March 2018

Abiotic degradation of chlorinated solvents by reactive iron minerals such as iron sulfides, magnetite, green rust, and other Fe(II)‐containing minerals has been observed in both laboratory and field studies. These reactive iron minerals form under iron‐ and sulfate‐reducing conditions which are commonly found in permeable reactive barriers (PRBs), enhanced reductive dechlorination (ERD) treatment locations, landfills, and aquifers that are chemically reducing. The objective of this review is to synthesize current understanding of abiotic degradation of chlorinated solvents by reactive iron minerals, with special focus on how abiotic processes relate to groundwater remediation. Degradation of chlorinated solvents by reactive minerals can proceed through reductive elimination, hydrogenolysis, dehydrohalogenation, and hydrolysis reactions. Degradation products of abiotic reactions depend on degradation pathways and parent compounds. Some degradation products (e.g., acetylene) have the potential to serve as a signature product for demonstrating abiotic reactions. Laboratory and field studies show that various minerals have a range of reactivity toward chlorinated solvents. A general trend of mineral reactivity for degradation of chlorinated solvents can be approximated as follows: disordered FeS > FeS > Fe(0) > FeS2 > sorbed Fe2+ > green rust = magnetite > biotite = vermiculite. Reaction kinetics are also influenced by factors such as pH, natural organic matter (NOM), coexisting metal ions, and sulfide concentration in the system. In practice, abiotic reactions can be engineered to stimulate reactive mineral formation for groundwater remediation. Under appropriate site geochemical conditions, abiotic reactions can occur naturally, and can be incorporated into remedial strategies such as monitored natural attenuation.
A Simple and Affordable System for Installing Shallow Drive Point Piezometers
Authors: Burk Lawrence , Cook Peter G.
Published: March 2018

This paper describes a drive point system for installing small‐diameter (15 to 25 mm ID) piezometers to depths of several metres in unconsolidated sediments. The system fills the gap between (1) heavy duty drive point systems powered by drilling rig hydraulics or air hammers that are capable of installing large diameter drive points to depths of many tens of metres and (2) manually driven systems that typically install 10 mm ID or smaller tubing to depths of <2 m. Unlike many existing systems, which install piezometers inside an outer casing that is later removed, our system protects the piezometer screen inside the casing and extends it only once the casing is driven to the desired depth. This avoids clogging of the screen during installation and the risk of creating an annulus around the piezometer, which can provide a preferential pathway for water movement. The piezometer has a larger diameter than most manually driven systems, and thus has a higher yield; it also permits use of most commercially available pressure transducers and electrical conductivity sensors. The piezometers have been successfully installed to depths of up to 6 m using an electric hammer. The system overcomes some issues associated with existing systems and provides the advantages of affordability, rapid installation, mechanical assistance and manual portability.
Biofilm Detection in a Model Well‐Bore Environment Using Low‐FieldNMR
Authors: Kirkland Catherine M. , Hiebert Randy , Phillips Adrienne , Grunewald Elliot , Walsh David O. , Seymour Joseph D. , Codd Sarah L.
Published: March 2018

This research addresses the challenges of the lack of non‐invasive methods and poor spatiotemporal resolution associated with monitoring biogeochemical activity central to bioremediation of subsurface contaminants. Remediation efforts often include growth of biofilm to contain or degrade chemical contaminants, such as nitrates, hydrocarbons, heavy metals, and some chlorinated solvents. Previous research indicates that nuclear magnetic resonance (NMR) is sensitive to the biogeochemical processes of biofilm accumulation. The current research focuses on developing methods to use low‐costNMRtechnology to support in situ monitoring of biofilm growth and geochemical remediation processes in the subsurface. Biofilm was grown in a lab‐scale radial flow bioreactor designed to model the near wellbore subsurface environment. The Vista Clara JavelinNMRlogging device, a slim down‐the‐borehole probe, collectedNMRmeasurements over the course of eight days while biofilm was cultivated in the sand‐packed reactor. MeasuredNMRmean logT2relaxation times decreased from approximately 710 to 389 ms, indicating that the pore environment and bulk fluid properties were changing due to biofilm growth. Destructive sampling employing drop plate microbial population analysis and scanning electron and stereoscopic microscopy confirmed biofilm formation. Our findings demonstrate that theNMRlogging tool can detect small to moderate changes inT2distribution associated with environmentally relevant quantities of biofilm in quartz sand.
Evaluating the Use of In‐Well Heat Tracer Tests to Measure Borehole Flow Rates
Authors: Sellwood Stephen M. , Hart David J. , Bahr Jean M.
Published: March 2018

Recent research has demonstrated the use of in‐well heat tracer tests monitored by a fiber optic distributed temperature sensing (DTS) system to characterize borehole flow conditions in open bedrock boreholes. However, the accuracy of borehole flow rates determined from in‐well heat tracer tests has not been evaluated. The purpose of the research presented here is to determine whether borehole flow rates obtained using DTS‐monitored in‐well heat tracer tests are reasonable, and to evaluate the range of flow rates measureable with this method. To accomplish this, borehole flow rates measured using in‐well heat tracer tests are compared to borehole flow rates measured in the same boreholes using an impeller or heat pulse flowmeter. A comparison of flow rates measured using in‐well heat tracer tests to flow rates measured with an impeller flowmeter under the same conditions showed good agreement. A comparison of in‐well heat tracer test flow rate measurements to previously‐collected heat pulse flowmeter measurements indicates that the heat tracer test results produced borehole flow rates and flow profiles similar to those measured with the heat pulse flowmeter. The results of this study indicate that borehole flow rates determined from DTS‐monitored in‐well heat tracer tests are reasonable estimates of actual borehole flow rates. In addition, the range of borehole flow rates measurable by in‐well heat tracer tests spans from less than 10−1 m/min to approximately 101 m/min, overlapping the ranges typically measurable with an impeller flowmeter or a heat pulse flowmeter, making in‐well heat tracer testing a versatile borehole flow logging tool.
Electrical Resistance Heating of Clay Layers in Water‐Saturated Sand
Authors: Martin Eric J. , Mumford Kevin G. , Kueper Bernard H.
Published: March 2018

Electrical resistance heating (ERH) experiments were performed in a two‐dimensional water‐saturated porous medium comprising an electrically conductive, low‐permeability clay lens embedded within a less electrically conductive, higher permeability silica sand. These were compared to experiments performed in homogeneous silica sand. All experiments were performed in the absence of a non‐aqueous phase liquid (NAPL) or dissolved volatile organic compound (VOC). Temperature monitoring showed preferential heating in the clay lens and higher overall heating rates throughout the test cell compared to the homogeneous case. Gas production was localized around the sand–clay interface due to high temperature and low capillary displacement pressure. Above the clay lens, unexpected temperature plateaus were observed, similar to those observed in previous experiments during NAPL–water co‐boiling. A conceptual model based on the consumption of thermal energy as latent heat of vaporization in the highly localized heating and gas production region adjacent to the clay lens is proposed to explain the temperature plateaus. Supporting data is drawn from images of the gas phase and electric current measurements. These results show that the use of co‐boiling plateaus as an indicator of NAPL–water co‐boiling could be misleading during applications of ERH at sites containing electrically conductive, low‐permeability clay lenses embedded within less electrically conductive, higher‐permeability sands.
Evaluation of Long‐Term Performance and Sustained Treatment at Enhanced Anaerobic Bioremediation Sites
Authors: McGuire Travis M. , Adamson David. T. , Burcham Michael S. , Bedient Philip B. , Newell Charles J.
Published: March 2018

This study evaluated the long‐term performance of enhanced anaerobic bioremediation (EAB) at chlorinated solvent sites to determine if sustained treatment processes were helping to prevent concentration rebound. A database of groundwater concentration versus time records was compiled for 34 sites, with at least 3 years of posttreatment monitoring data (median = 4.7 years, range = 3.0 to 11.7 years). Long‐term performance was evaluated based on order‐of‐magnitude (OoM) changes in parent compound concentrations during various monitoring periods. Results indicate that, relative to the pretreatment concentration, a median concentration reduction for all 34 sites of 1.0 OoM (90% reduction) was achieved by the end of the posttreatment monitoring period. No rebound was observed at 65% of the sites between the first year of posttreatment monitoring and the final year. During this posttreatment period, Mann‐Kendall trend analysis indicated that the concentration was stable or decreasing at 89% of the sites where a trend could be established (n = 27; 33% decreasing, 56% stable, 11% increasing). Statistical analysis indicates there is no evidence that the distribution of median concentration reductions after the first year of posttreatment monitoring was different than the distribution of median reductions 2 to 11 years later at the end of the monitoring period (p = 0.67). Similarly, statistical analysis indicates that there is no evidence that the distribution of median reductions for a larger set of sites (n = 84) with less than 3 years of posttreatment monitoring data (1.1 OoM; 92% reduction) was different than the distribution of median OoM reductions for the 34‐site dataset with longer monitoring periods (p = 0.80). This suggests that, at a typical site, a 3‐year monitoring period should be sufficient for evaluating performance. The results of this study indicate that, in the long term, after the end of active treatment, sustained treatment processes contribute to relatively modest concentration reductions but do mitigate rebound at the majority of EAB sites.
Geochemical Distribution of Trace Elements in Groundwater from the North Mara Large‐Scale Gold Mining Area of Tanzania
Authors: Rwiza Mwemezi Johaiven , Kim, Kyoung‐Woong , Kim Sang‐don
Published: March 2018

The influence of large‐scale mining operations on groundwater quality was investigated in this study. Trace element concentrations in groundwater samples from the North Mara mining area of northern Tanzania were analyzed. Statistical analyses for relationships between elemental concentrations in the samples and distance of a sampling site from the mine tailings dam were also conducted. Eleven trace elements (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) were determined, and averages of Fe and Al concentrations were higher than levels accepted by the Tanzanian drinking water guideline. Levels of Pb in three samples were higher than the World Health Organization (WHO) and United States Environmental Protection Agency (USEPA) drinking water guidelines of 10 and 15 µg/L, respectively. One sample contained a higher As level than the WHO and USEPA guideline of 10 µg/L. The correlation between element concentrations and distance from the mine tailings dam was examined using the hierarchical agglomeration cluster analysis method. A significant difference in the elemental concentration existed depending on the distance from the mine tailings dam. Mann–Whitney U‐test post hoc analysis confirmed a relationship between element concentration and distance of a sampling site from the mine tailings dam. This relationship raises concerns about the increased risks of trace elements to people and ecosystem health. A metal pollution index also suggested a relationship between elemental concentrations in the groundwater and the sampling sites’ proximity from the mine tailings dam.