bluuebunny/crossref_metadata_2025_split huggingface dataset:
Shutdown of BAC filters: effects on water quality
Authors: Niquette Patrick , Prévost Michèle , Servais Pierre , Beaudet Jean‐François , Coallier Josée , Lafrance Pierre 
Published: February 2018

Adding a filter backwash after shutdown restored the quality of filtered water to its preshutdown standard.Biological activated carbon (BAC) filtration is used in drinking water treatment to biodegrade dissolved organic carbon (DOC) and to nitrify ammonia. This study evaluated BAC filters before, during, and after shutdown. Concentrations of five substrates were measured: ammonia, nitrite, nitrate, DOC, and dissolved oxygen. Media samples were taken simultaneously at similar depths to evaluate the effect of a shutdown on the densities of fixed bacteria. Dissolved oxygen concentrations quickly dropped below 2 mg/L within the BAC filters during the first 2 h of filter shutdown. At the same time, nitrite and bromide concentrations increased rapidly. Fixed bacterial biomass densities, measured at several depths in the filter after a 24‐h shutdown, declined. Concentrations of DOC and ammonia, measured in the effluent after the filter was restarted, were higher than those measured before shutdown. Backwashing after shutdown, before the filter was returned to normal operation, eliminated these negative effects and restored the biodegradation performance of the BAC filters.
DBP formation potential of aquatic humic substances
Authors: Pomes Michael L. , Green W. Reed , Thurman E. Michael , Orem William H. 
Published: February 2018

Terrestrial vegetation commonly shed into reservoirs contains chemical precursors of DBPs.Aquatic humic substances (AHSs) in water generate potentially harmful disinfection by‐products (DBPs) such as haloacetic acids (HAAs) and trihalomethanes (THMs) during chlorination. AHSs from two Arkansas reservoirs were characterized to define source, identify meta‐dihydroxybenzene (m‐DHB) structures as probable DBP precursors, and evaluate predicted HAA and THM formation potentials. Elemental nitrogen content < 1 percent, phenol content > 0.5 μeq/mg, δ13C values of –27%o, and low yields of syringyl phenols found by cupric oxide (CuO) oxidation suggest a pine tree source for the AHSs found in the Maumelle and Winona reservoirs in Little Rock, Ark. CuO oxidation yielded fewer m‐DHB structures in Maumelle AHSs than in Winona AHSs. A higher 3,5‐dihydroxybenzoic acid (3,5‐DHBA) content correlated with increased HAA and THM formation potential. The 3,5‐DHBA concentration in Winona AHSs was similar to the range found in AHSs extracted from deciduous leaf litter, twigs, and grass leachates.
Desktop guidance for mitigating Pb and Cu corrosion by‐products
Authors: Edwards Marc , Jacobs Sara , Dodrill Donna 
Published: February 2018

Desktop studies accurately predict trends in corrosion by‐product release.Utility experiences were examined to assess the reliability of solubility models and decision trees in forecasting control of lead (Pb) and copper (Cu) corrosion by‐products. Such approaches cannot quantitatively predict effectiveness of corrosion control. For example, even the best‐fit solubility models explain only about 35 and 18 percent of the quantitative variation in 90th percentile Cu and Pb release, respectively. However, the decision trees and solubility models are qualitatively consistent with utility experience and are thus useful when promising water quality changes are identified to mitigate corrosion by‐product release. Utility experiences confirm that an optimal alkalinity range (20–40 mg/L as CaCO3) exists for Pb corrosion control above pH 8.5, a higher mass ratio of chloride to sulfate tends to worsen Pb by‐product release, and detectable color can signal a natural organic material content that may adversely affect compliance with the Cu action limit.
Model calibration data: the good, the bad, and the useless
Authors: Walski Thomas M. 
Published: February 2018

Comparisons between field data and model results need to be made with “good” field data.Water distribution models are used to simulate a variety of conditions, including extreme flow events such as maximum hour demands and fire flows. Some models are tested only under average demand conditions, in which head loss is commonly of the same order of magnitude as errors in head loss measurements. Data collected when head loss is small in comparison with errors may give the false impression that the model is properly calibrated. Substantial errors may exist in the model that will not become apparent until the model is used at a time when head loss and velocity are high. This article contains guidelines for collecting data so that the model calibration will be meaningful.
Applying DBP models to full‐scale plants
Authors: Westerhoff Paul , Debroux Jean , Amy Gary L. , Gatel Dominique , Mary Veronique , Cavard Jacques 
Published: February 2018

A case study suggests that the use of site‐specific reactivity coefficients and chlorine consumption results in more accurate models of trihalomethane formation.Because of increasing concern about balancing health risks for microbiological control and disinfection by‐product formation, utilities are closely examining and optimizing disinfection practices. The authors present a methodology for developing site‐specific, inplant (finished water) chlorine (Cl2) residual and trihalomethane (THM) formation models. In a case study, the methodology was applied at three operating water treatment plants in the Paris suburbs. A key obstacle was the limited historical record of bromide (Br–) occurrence. However, lab chlorination experiments indicated that approximately 10 percent of Br– was typically incorporated into THMs. In‐plant Cl2 residuals were accurately simulated with a simple first‐order Cl2 consumption model. The most accurate THM simulations were obtained using a recently developed US Environmental Protection Agency model that incorporates species‐specific reactivity parameters.
Assessing biodegradable organic matter
Authors: Volk Christian J. , LeChevallier Mark W. 
Published: February 2018

High temperature, high BOM concentration, and low disinfectant residual promote regrowth of coliforms in distribution systems.This article summarizes data collected during various surveys that assessed four aspects of biodegradable organic matter (BOM) in drinking water: (1) BOM concentrations entering distribution systems, (2) the relationship between concentrations of assimilable organic carbon (AOC) and biodegradable dissolved organic carbon (BDOC), (3) field tests of a simple method of measuring BDOC using bioreactors, and (4) the effect of BOM on coliform occurrences in distribution networks. Overall, average concentrations of AOC and BDOC in plant effluent were 100 μg/L and 0.32 mg/L, respectively. A statistically significant but weak relationship between AOC and BDOC concentrations suggests that both parameters need to be monitored during biostability studies because they provide different pieces of information. BDOC bioreactors are useful for measuring BDOC concentrations at water utilities. However, they require a long time to colonize and must adapt to water at the site where they are used. Coliform occurrences were associated with three factors: temperature, disinfectant type and concentration, and AOC concentration. When threshold values for these factors were exceeded (15oC, AOC > 100 μg/L, and dead‐end disinfectant residuals < 0.5 mg/L for free chlorine or 1.0 mg/L for chloramines), the probability of coliform occurrences greatly increased.
Monochloramine and Legionnaires' disease
Authors: Kool Jacob L. , Carpenter Joseph C. , Fields Barry S. 
Published: February 2018

Use of monochloramine as a residual disinfectant could prevent Legionnaires' disease in communities throughout the United States.Legionnaires' disease is caused by Legionella bacteria, which live in biofilm in natural and synthetic aquatic environments. The most frequent route of infection is inhalation of contaminated aerosol, which is often produced by faucets, showers, or cooling towers. Although the disease can be disseminated in potable water, the effects of the disinfection methods used by municipal water treatment facilities on the occurrence of Legionnaires' disease have not been studied. This article describes an epidemiological study in which methods for disinfecting potable water supplied to 32 hospitals where outbreaks of Legionnaires' disease have occurred are compared with methods for water supplied to 48 randomly selected control hospitals. Hospitals supplied with drinking water containing free chlorine were 10.2 times more likely to have reported an outbreak of Legionnaires' disease associated with potable water than hospitals that used water with monochloramine as a residual disinfectant (odds ratio—10.2; 95 percent confidence interval—1.4–460).
Cryptosporidium during a simulated outbreak
Authors: Gale Paul , Stanfield Geoff 
Published: February 2018

Monitoring programs often underestimate the total oocyst loading and, thus, the risk of infection.Counts of Cryptosporidium oocysts in 100‐L volume “spot” samples of treated water have been simulated for conditions representative of an outbreak. The counts agree well with those reported in outbreaks in the United Kingdom and the United States. Whereas 33 percent of 100‐L samples contained no oocysts, a small proportion contained hundreds and even thousands of oocysts. The risk of Cryptosporidium infection is directly related to the total number of oocysts entering the distribution system in the treated water as represented by the arithmetic mean oocyst density. Monitoring programs based on taking single spot 100‐L volume samples will tend to miss the “all important” high‐count samples and thus underestimate the arithmetic mean and the risk to public health. Spot samples recording 0 oocysts/100 L therefore provide very little reassurance. To detect temporal variation in the form of infrequent high‐count spikes, the Cryptosporidium regulations in the United Kingdom require continuous monitoring of treated water as it leaves the treatment facility.
Preozonation effects on coagulation
Authors: Schneider Orren D. , Tobiason John E. 
Published: February 2018

Depending on the type of coagulant used, preozonation can help or hinder the removal of organic matter.The effects of preozonation on interactions among coagulants, particles, and natural organic matter were examined at bench scale through a series of jar tests using different organic matter, pH values, and coagulants. When alum was used as a coagulant, preozonation hindered turbidity and dissolved organic matter (DOM) removal at the conditions tested. When cationic polymers were used as the coagulant, however, preozonation led to small but statistically significant increases in the removal of both turbidity and DOM. When polyaluminum chloride was used as the coagulant for several natural waters, preozonation aided turbidity and DOM removal in one instance and hindered removal of particles and organic materials in another instance. The authors hypothesize that preozonation reduces the surface charge of particulates, leading to better coagulation by charge neutralization.
Tissue engineering of human knee meniscus using functionalized and reinforced silk‐polyvinyl alcohol composite three‐dimensional scaffolds: Understanding the in vitro and in vivo behavior
Authors: Pillai Mamatha Muraleedharan , Gopinathan Janarthanan , Senthil Kumar Rathinasamy , Sathish Kumar Gopal , Shanthakumari Sivanandam , Sahanand Kulasekaran Santosh , Bhattacharyya Amitava , Selvakumar Rajendran 
Published: February 2018

AbstractTissue engineered constructs with rapid restoration of mechanical and biological properties remain a challenge, emphasizing the need to develop novel scaffolds. Here, we present a multicomponent composite three‐dimensional scaffold structure with biomimetic reinforcement and biomolecule functionalization for meniscus tissue engineering. The scaffold structure was developed using 3:1 silk fibroin (SF) and polyvinyl alcohol (PVA). Autoclaved eggshell membrane (AESM) powder (1–3%w/v) was used as reinforcement to enhance biomechanical properties. Further to improve cell attachment and proliferation, these scaffolds were functionalized using an optimized unique combination of biomolecules. Comprehensive analysis of scaffolds was carried out on morphological, structural, mechanical and biological functionalities. Their mechanical properties were compared with different native human menisci. The results indicated that, functionalized SF‐PVA with 3%AESM has shown similar order of magnitude of compressive and dynamic mechanical properties as in human meniscus. Moreover, 3% AESM based scaffolds were found to support better primary human meniscal cellular proliferation and extracellular matrix secretion. Immunohistochemical analysis revealed angiogenesis and biocompatibility with minimal inflammatory response for subcutaneously implanted scaffolds in New Zealand white rabbits. The developed reinforced and functionalized SF‐PVA scaffolds can uniquely combine the potential for load‐bearing properties with improved in vitro and in vivo support for meniscus tissue regeneration. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1722–1731, 2018.
Combining advantages: Direct correlation of two‐dimensional microcomputed tomography datasets onto histomorphometric slides to quantify three‐dimensional bone volume in scaffolds
Authors: Westhauser F. , Reible B. , Höllig M. , Heller R. , Schmidmaier G. , Moghaddam A. 
Published: February 2018

AbstractMicrocomputed tomography (mCT) belongs to the most powerful tools for the three‐dimensional (3D) assessment of bone. While it is possible to refer to landmarks in mCT scans of actual bone structure, the assessment of calcified osteoid within scaffolds is problematic, due to the missing morphological correlates. Therefore, bone formation within scaffolds is mostly analyzed using indirect parameters such as changes in volume or surface alteration, preserving histomorphometry the gold standard in the direct analysis of bone formation. The presented method combines the advantages of mCT and histomorphometry: by creating an overlay image of the exact same histomorphometric and mCT slice, a grey‐value‐threshold representing calcified tissue was defined. Compared to the scaffolds global threshold, a direct evaluation of bone formation within scaffolds is possible by mCT—applied on the whole dataset, evaluation of bone volume is achievable. Two groups of human mesenchymal‐stem‐cell‐seeded ß‐Tricalciumphosphate‐scaffolds were analyzed: whilst group B was stimulated with 0.1 µg/mL Bone Morphogenetic Protein‐7, group A remained unstimulated during in vivo differentiation. Strong correlations (r > 0.8) were obtained between percentage bone area in mCT and histomorphometry, as well as for 3D bone volume. Using the presented method, 3D bone volume can be directly estimated within scaffolds by combination of histomorphometric and mCT‐analysis. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1812–1821, 2018.
Fatigue and quasi‐static mechanical behavior of bio‐degradable porous biomaterials based on magnesium alloys
Authors: Hedayati R. , Ahmadi S. M. , Lietaert K. , Tümer N. , Li Y. , Amin Yavari S. , Zadpoor A. A. 
Published: February 2018

AbstractMagnesium and its alloys have the intrinsic capability of degrading over timein vivowithout leaving toxic degradation products. They are therefore suitable for use as biodegradable scaffolds that are replaced by the regenerated tissues. One of the main concerns for such applications, particularly in load‐bearing areas, is the sufficient mechanical integrity of the scaffold before sufficient volumes ofde novotissue is generated. In the majority of the previous studies on the effects of biodegradation on the mechanical properties of porous biomaterials, the change in the elastic modulus has been studied. In this study, variations in the static and fatigue mechanical behavior of porous structures made of two different Mg alloys (AZ63 and M2) over different dissolution times (,, and) have been investigated. The results showed an increase in the mechanical properties obtained from stress–strain curve (elastic modulus, yield stress, plateau stress, and energy absorption) afterand a sharp decrease after. The initial increase in the mechanical properties may be attributed to the accumulation of corrosion products in the pores of the porous structure before degradation has considerably proceeded. The effects of mineral deposition was more pronounced for the elastic modulus as compared to other mechanical properties. That may be due to insufficient integration of the deposited particles in the structure of the magnesium alloys. While the bonding of the parts being combined in a composite‐like material is of great importance in determining its yield stress, the effects of bonding strength of both parts is much lower in determining the elastic modulus. The results of the current study also showed that the dissolution rates of the studied Mg alloys were too high for direct use in human body. © 2018 Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1798–1811, 2018.
Comparison of the CMNC and MNC apheresis protocol for the collection of T‐cells showed comparable outcome: An observational study in a single centre
Authors: Putensen Daniel , Smith Richard , Pilcher Linda , Trandafir George 
Published: February 2018

ABSTRACTBackgroundAn increasing demand for human lymphocytes require an efficient, reliable and reproducible lymphocyte process. Here, we compare the Spectra Optia® CMNC protocol with the Optia MNC platform in unmobilised donor lymphocyte collections.PurposeTo establish and compare the feasibility, efficiency, and practicability of the two apheresis protocols.MethodsData was collected prospectively from 60 non‐cytokine stimulate donors who underwent a total of 64 T‐cell collection procedures. Of these, 24 procedures were performed in the CMNC cohort and 40 procedures in the MNC cohort. All donors in the CMNC group were related; all donors in the MNC group were donors from a registry. Donor characteristics, procedure parameters and cellular product content were analysed and compared.ResultsDonor characteristics and full blood count results were comparable, except the median white blood cell count, which was higher in the CMNC cohort (6.87 vs. 5.58 ×109/L, P < .005). This resulted in higher lymphocyte (1.95 vs. 1.57 ×109/L, P < .009) and CD3+ cell counts (1476 vs. 1060/L, P < .02). A total blood volume processed of 2.0 resulted in i) run time (222 vs. 242 min), ii) product volume (192 vs. 183 ml), iii) platelet content (2140 vs. 1345 ×106/ml, P < .003). CD3+ CE2 (%): 54.7 vs. 50.4.ConclusionThe CMNC and MNC protocols are reliable, efficient and comparable in performance parameters and cell composition of final product, respectively. One advantages of the CMNC protocol is the potential ability to tailor the cell composition of the final product accordingly to demands from cell processing laboratories.
Evaluation of electron tomography reconstruction methods for interface roughness measurement
Authors: Hayashida Misa , Ogawa Shinichi , Malac Marek 
Published: February 2018

AbstractWe evaluate the suitability of simultaneous iterative reconstruction technique (SIRT), filtered back projection, and simultaneous algebraic reconstruction technique methods for buried interface roughness measurements. We also investigate the effect of total electron dose distributed over the entire tilt series on measured roughness values. We investigate the applicability of the dose fractionation theorem by evaluating the effect of an increasing number of images, i.e., decreasing tilt increment size at fixed total electron irradiation dose on the quantitative measurement of buried interface roughness. The results indicate that SIRT is the most suitable method for reconstruction and a 3° to 5° angle is optimal for the roughness measurement.
Rapid and Selective Detection of Cyanide Anion by Enhanced Fluorescent Emission and Colorimetric Color Changes at Micromole Levels in Aqueous Medium
Authors: Qu Wen‐Juan , Li Wen‐Ting , Zhang Hai‐Li , Wei Tai‐Bao , Lin Qi , Yao Hong , Zhang You‐Ming 
Published: February 2018

One main source of cyanide (CN−) exposure for mammals is through the plant consumption; thus, the sensitive and selective cyanide detection in plant tissue is a significant and urgent work. Here, a simple sensor N′‐(2,4‐dihydroxybenzylidene)naphtha[2,1‐b]furan‐2‐carbohydrazide (Q1‐3) was designed and synthesized for selective and sensitive dual‐channel detection of cyanide in aqueous medium (DMSO/H2O, 1:9, v/v). Acylhydrazone and phenolic hydroxyl groups on Q1‐3 are the recognition sites, and naphthofuran group is the signal report group. The intramolecular charge transfer between the benzene group and naphthofuran group was impeded because of the electron‐withdrawing groups (hydroxyl) on sensor Q1‐3. Interestingly, the sensor Q1‐3 exhibited an intramolecular charge transfer absorption band at 400 nm and emission band at 500 nm, respectively, directly realizing an “OFF–ON” response after the deprotonation process induced by cyanide anions in aqueous medium (DMSO/H2O, 1:9, v/v). Notably, this sensor was successfully applied to detect cyanide anions in food samples, which proves a very simple and selective platform for on‐site monitoring of cyanide in agriculture samples. In addition, the test strips and silica gel plates based on Q1‐3 were also fabricated, which could act as test kits and silica gel plates for convenient and efficient detection of cyanide anions.
Neutrophil heterogeneity: Bona fide subsets or polarization states?
Authors: Deniset Justin F , Kubes Paul 
Published: February 2018

AbstractNeutrophils are key components of the innate immune system that play important roles during infection, injury, and chronic disease. In recent years, neutrophil heterogeneity has become an emerging focus with accumulating evidence of neutrophil populations with distinct functions under both steady-state and pathologic conditions. Despite these advances, it remains unclear whether these different populations represent bona fide subsets or simply activation/polarization states in response to local cues. In this review, we summarize the varied neutrophils populations that have been described under both basal and during inflammation. We discuss the evidence that supports the existence of neutrophils subsets. Finally, we identify potential gaps in our knowledge that may further advance our current understanding of neutrophil heterogeneity.