Comprehensive Assessment of Exposure Pathways for Perfluoroalkyl Ether Carboxylic Acids (PFECAs) in Residents Near a Fluorochemical Industrial Park: The Unanticipated Role of Cereal Consumption.

With the replacement of perfluorooctanoic acid (PFOA) with perfluorinated ether carboxylic acids (PFECAs), residents living near fluorochemical industrial parks (FIPs) are exposed to various novel PFECAs. Despite expectations of low accumulation, short-chain PFECAs, such as perfluoro-2-methoxyacetic acid (PFMOAA), previously displayed a considerably high body burden, although the main exposure routes and health risks remain uncertain. Here, we explored the distribution of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in diverse environmental media surrounding a FIP in Shandong Province, China. PFECAs were found at elevated concentrations in all tested matrices, including vegetables, cereals, air, and dust. Among residents, 99.3% of the ∑36PFAS exposure, with a 43.9% contribution from PFECAs, was due to gastrointestinal uptake. Dermal and respiratory exposures were negligible at 0.1 and 0.6%, respectively. The estimated daily intake (EDI) of PFMOAA reached 114.0 ng/kg body weight (bw)/day, ranking first among all detected PFECAs. Cereals emerged as the dominant contributor to PFMOAA body burden, representing over 80% of the overall EDI. The median EDI of hexafluoropropylene oxide dimer acid (HFPO-DA) was 17.9 ng/kg bw/day, markedly higher than the USEPA reference doses (3.0 ng/kg bw/day). The absence of established threshold values for other PFECAs constrains a comprehensive risk assessment.

Solvent-like bis (2-chloro-1-methylethyl) ether occurrence in drinking water: Multidimensional risk assessment integrated health and aesthetic aspects.

Bis (2-chloro-1-methylethyl) ether (DCIP), one U.S. Environmental Protection Agency priority pollutant, could pose health and/or odor risk in water environment. In this study, odor characteristics, occurrence and source of DCIP in drinking waters of China were investigated based on sensory analysis and a nation-wide investigation covering 140 drinking water treatment plants. Then multi-risk integrated health and aesthetic aspects through oral and inhalation (showering) exposure by drinking water were first estimated. Sensory evaluation showed DCIP exhibited "solvent-like" odor with thresholds of 34.8 ng/L in air and 142.0 ng/L in water. DCIP was detected at comparable concentrations in raw and finished waters (<1280 ng/L) and was by-product from industrial production of epichlorohydrin/propylene oxide. Lifetime Average Daily Dose through oral exposure was 0-36.65 ng/day/kg, corresponding to odor activity values of 0-8.4 and hazard quotients of far < 1, indicating drinking tap water might cause odor issues rather than significant health hazard. The proportion of sensitive population to DCIP's odor was 6.1%. In contrast, residents rarely detect DCIP's odor by inhalation. The presence in drinking water as industrial by-product, poor removal using conventional water treatment and potential to be T&O issues, indicates urgent demand for pollutant source control to protect DCIP from entering source waters.

Occurrence and ecological risk assessment of 2,2',4,4'-tetrabromodiphenyl ether and decabromodiphenyl ether in surface waters across China.

Polybrominated diphenyl ethers (PBDEs) are efficient brominated flame retardants and are released into various environmental media via usage, recycling and disposal. This study investigated the concentrations and ecological risks of two typical PBDEs, 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) and decabromodiphenyl ether (BDE-209), in surface waters across China from 2011 to 2018. The results showed that the concentration of BDE-209 (8.25 ng L-1) was higher than that of BDE-47 (1.02 ng L-1), and the concentrations of BDE-47 and BDE-209 in the lakes (2.56 ng L-1 and 22.19 ng L-1, respectively) were higher than those in the rivers (0.58 ng L-1 and 7.05 ng L-1, respectively). In addition, the concentration of BDE-209 in the wet season (2.61 ng L-1) was lower than that in the dry season (10.83 ng L-1), whereas the concentration of BDE-47 in the wet season (0.24 ng L-1) was a little lower than that in the dry season (0.99 ng L-1). BDE-47 and BDE-209 concentrations showed a gradual decrease in surface waters across China during the eight-year period. Based on the species sensitivity distribution (SSD) models, the 5% hazardous concentration (HC5) and predicted no-effect concentration (PNEC) values were derived using the acute and chronic toxicity data of BDE-47 and BDE-209. Results showed that the PNEC values based on the acute and chronic toxicity data were 2.08 µg L-1 and 0.52 µg L-1 for BDE-47, respectively and 370 µg L-1 and 0.34 µg L-1 for BDE-209, respectively. The risk quotient (RQ) values of BDE-47 in surface waters across China were far smaller than 0.1 (low ecological risk). Similarly, the RQ values of BDE-209 were also smaller than 0.1, except for those at Baiyangdian Lake and Chaohu Lake, where the probability of 0.1 ≤ RQ < 1.0 (medium ecological risk) was approximately 10% based on 10,000 Monte Carlo simulations.

Assessment of Genetic Variability and Bran Oil Characters of New Developed Restorer Lines of Rice (Oryza sativa L.).

Rice is one of the most important crops in Egypt. Due to the gap between the demand and the availability of the local edible oils, there is need to raise the nutritional value of rice and, therefore, to improve the nutritional value of the consumer. This research was carried out at the Experimental Farm of Sakha Agricultural Research Station, Sakha, Kafr El-Sheikh, Egypt, during the 2019 and 2020 seasons. Five newly developed genotypes of rice, namely NRL 63, NRL 64, NRL 65, NRL 66, and Giza 178 as check variety (control), were used to evaluate the analytical characterization of raw rice bran and rice bran oil from rice bran, study the genetic variability and genetic advance for various quantitative and qualitative traits in rice as well as, rice bran oil. The genotypes were evaluated in a randomized complete block design (RCBD) with three replications. Analysis of variance revealed highly significant variations among the genotypes for all the studied characters. Data revealed that high estimates of the phenotypic coefficient of variance (PCV%) and genotypic coefficient of variance (GCV%) were observed for amylose content percentage, peroxide value (meq/kg oil), myristic C14:0, and arachidic C20:0, indicating that they all interacted with the environment to some extent. The line NRL66 and NRL64 showed the highest and high values of mean performance for grain yield (t/h), grain type (shape), amylose content percentage, crude protein, ether extract and ash of milled rice, crude protein, ether extract, ash, phosphorus, magnesium, manganese, zinc, and iron of stabilized rice bran oil. Genetic advance as a percentage of mean was high for most of the studied traits. It indicates that most likely, the heritability is due to additive gene effects, and selection may be effective. The percentage of advantage over the Giza 178 as the commercial variety was significant and highly significant among the genotypes for all the characters studied in the two years, indicating that the selection is effective in the genetic improvements for these traits.

Assessment of different surface treatments and shear bond characteristics of poly-ether-ether-ketone: An in vitro SEM analysis.

Aim: The aim of this study is to assess the surface roughness and shear bond characteristics of pol-ether-ether-ketone after different surface treatments. Setting and Design: An in vitro, prospective. Materials and Methods: One hundred and twenty disc-shaped samples of 10 mm diameter and 2 mm thickness were milled and subjected to following surface treatments: 110 µm alumina particles, 98% concentrated sulfuric acid, and 10-20 µm synthetic diamond particles. Surface characteristics of treated sample were studied under SEM with ×500 and ×1000 magnification. Shear bond strength (SBS) with composite resin discs embedded in acrylic blocks after luting with self-etch resin cement and resin-modified glass ionomer cement (RMGIC) was evaluated using the universal testing machine (Instron®, Massachusetts U. S. A). Statistical Analysis Used: The data collected were evaluated using the Analysis of variance and Tukey's honest significant difference post hoc test. Results: Highest SBS and SR were noted with self-etch resin cement in the given order: 98% sulfuric acid (2.106 ± 0.186 µm), followed by alumina particles (1.706 ± 0.160 µm) and synthetic diamond particles (1.101 ± 0.167 µm). Conclusion: The SBS of self-etch resin cement was higher compared to RMGIC for all three surface treatments done on test samples. Hundred percent samples treated by all three surface treatment methods showed mixed type of failure.

Assessment of 3-dimensional bone augmentation of severely atrophied maxillary alveolar ridges using patient-specific poly ether-ether ketone (PEEK) sheets.

BACKGROUND: This study aimed to analyze the effectiveness of virtually designed polyether-ether ketone (PEEK) sheets to delineate and maintains the three-dimensional patient's maxillary alveolar ridge. MATERIALS AND METHODS: Fourteen patients (34 implants) with severely atrophied anterior maxillary alveolar ridges underwent rehabilitation using custom-made CAD/CAM PEEK sheets acting as a containment system for interpositional mix of particulate autogenous and xenogeneic bone graft, fixed by mono-cortical screws. Radiographic Assessment included measurements of linear changes in the vertical and horizontal dimensions on cross-sectional cuts of computed tomography (CBCT) using special software. RESULTS: Wound healing was uneventful for all the patients except one patient that showed wound break down 2 weeks postoperatively, which did not affect the outcome of the procedure. CBCT scans were interpreted to compare the quantity of both vertical and horizontal bone preoperatively and 6 months postoperatively. Statistical analyses demonstrated a significant difference between the results of both time intervals, with a mean vertical and horizontal bone gain was 3.47 mm(±1.46) and 3.42 (±1.1) with a P-value of (.0001). The customized sheets were removed 6 months postoperative with the successful placement of dental implants. CONCLUSION: The virtual planning of three-dimensional maxillary alveolar ridge augmentation utilizing patient-specific PEEK sheets deemed successful to restore the deficient ridge and to accommodate suitable size dental implants.

Assessment of three dimensional bone augmentation of severely atrophied maxillary alveolar ridges using prebent titanium mesh vs customized poly-ether-ether-ketone (PEEK) mesh: A randomized clinical trial.

BACKGROUND: Alveolar bone grafting techniques and dental rehabilitation of patients with maxillary alveolar defects is a very challenging and costly procedure. Various methods have been described to reconstruct these defects in order to facilitate the placement of dental implants. The aim of this study was to assess three dimensional (3D) maxillary ridge augmentation using two innovative, accurate, and time saving protocols. MATERIALS AND METHODS: Sixteen patients (32 implants) with vertically and horizontally deficient maxillary alveolar ridges, were equally allocated into 2 groups; a mix of particulate autogenous and xenogenic bone grafts loaded in a prebent titanium mesh (Control group) vs patient specific poly-ether-ether ketone meshes (Study group). Radiographic assessment was performed preoperatively, 1 week and 6 months postoperatively. Assessment included measurements of linear changes in the vertical and horizontal dimensions on cross sectional cuts of cone beam computed tomography using special software. Finally; the percentage of 3D bone gain in each group was compared to that of the other. RESULTS: Wound healing was uneventful for all cases except one patient in each group were the meshes were exposed 2 weeks' postsurgery. There was no statistical significance between both groups (P value = 0.2). CONCLUSION: Within the limitations of the sample size of this study, both techniques could be used as a successful method of ridge augmentation with no statistical significance between them.

Two-generational reproductive toxicity assessment of 6:2 chlorinated polyfluorinated ether sulfonate (F-53B, a novel alternative to perfluorooctane sulfonate) in zebrafish.

As an alternative to perfluorooctane sulfonate (PFOS), 6:2 chlorinated polyfluorinated ether sulfonate (commercial name: F-53B) has been used in the Chinese chrome plating industry for over four decades. It has been increasingly detected in environmental matrices in recent years, causing great concern regarding its potential health risks to humans and wildlife. However, its adverse effects on biota remain largely unknown. To explore the chronic toxicity of F-53B on reproduction, a two-generational study was conducted using zebrafish (Danio rerio). Adult zebrafish (F0 generation) were chronically exposed to different concentrations of F-53B (0, 5, 50, and 500 µg/L) for 180 d using a flow-through exposure system, with F1 and F2 generations reared without exposure. The reproductive toxicity endpoints were assessed in F0 and F1 adult fish. Results showed that F-53B accumulated in the F0 gonads and transferred to the F1 generation via maternal eggs, and even remained in F1 adult fish and their eggs (F2) after 180 d depuration. In the F0 generation, F-53B exposure significantly inhibited growth and induced reproductive toxicity, including decreased gonadosomatic index and egg production/female, changes in the histological structure of the gonads, and increased serum testosterone levels. In particular, serum estradiol and vitellogenin levels were significantly increased in 5 µg/L F-53B-exposed adult males. The transcriptional levels of several genes along the hypothalamic-pituitary-gonadal axis were altered in F0 generation fish. Testis transcriptome analysis revealed that F-53B exposure disrupted spermatogenesis in F0 male zebrafish. Maternal transfer of F-53B also induced adverse effects on growth and reproduction in the F1 generation. Furthermore, the higher occurrence of malformation and lower survival in F1 and F2 embryos indicated that parental exposure to F-53B could impair the embryonic development of offspring. Taken together, this study demonstrated that F-53B could induce reproductive toxicity in zebrafish similar to that induced by legacy PFOS, and its potential adverse effects on offspring deserve further investigation.

Cembrene Diterpenoids with Ether Linkages from Sarcophyton ehrenbergi: An Anti-Proliferation and Molecular-Docking Assessment.

Three new cembrene diterpenoids, sarcoehrenbergilid A-C (1-3), along with four known diterpenoids, sarcophine (4), (+)-7α,8ß-dihydroxydeepoxysarcophine (5), sinulolide A (6), and sinulolide B (7), and one steroid, sardisterol (8), were isolated and characterized from a solvent extract of the Red Sea soft coral Sarcophyton ehrenbergi. Chemical structures were elucidated by NMR and MS analyses with absolute stereochemistry determined by X-ray analysis. Since these isolated cembrene diterpenes contained 10 or more carbons in a large flexible ring, conformer stabilities were examined based on density functional theory calculations. Anti-proliferative activities for 1-8 were evaluated against three human tumor cell lines of different origins including the: lung (A549), colon (Caco-2), and liver (HepG2). Sardisterol (8) was the most potent of the metabolites isolated with an IC50 of 27.3 µM against the A549 cell line. Since an elevated human-cancer occurrence is associated with an aberrant receptor function for the epidermal growth factor receptor (EGFR), molecular docking studies were used to examine preferential metabolite interactions/binding and probe the mode-of-action for metabolite-anti tumor activity.

Chemical oxidation of bis(2-chloroethyl) ether in the Fenton process: Kinetics, pathways and toxicity assessment.

Bis(2-chloroethyl) ether (BCEE) is a common chemical material and a frequently detected contaminant in groundwater. It has a strong toxicity and some other chemicals such as poly(vinyl chloride-co-isobutyl vinyl ether) contain similar chloroaliphatic ether structure. So the effective degradation method and transformation pathways for BCEE need to be learned. The present study compared the degradation rate of BCEE by Fenton's reagent and other common oxidation methods, and optimized the reaction conditions. Oxidation intermediates and pathways were also proposed and toxicities of the intermediates were investigated. Results showed that Fenton was highly effective to degrade BCEE. pH, Fe2+ and H2O2 concentration all affected the oxidation rate, among which Fe2+ was the most significant variable. A total of twelve chlorinated intermediates were detected. Three main reaction pathways involved cleavage of the ether bond, hydroxyl substitution for hydrogen, and radical coupling. The pathways could be well interpreted and supported by theoretical calculations. The reaction mixture showed a decreasing trend in TOC concentration and toxicity until totally harmless to Vibrio fischeri after 15 min, but it was noteworthy that toxicities of some dimeric intermediates were stronger than BCEE by calculation.

Management practices, physically effective fiber, and ether extract are related to bulk tank milk de novo fatty acid concentration on Holstein dairy farms.

The objective of this study was to evaluate the relationship of management practices and dietary factors with de novo fatty acid concentration in bulk tank milk from commercial dairy farms milking Holstein cows. Farms were selected based on de novo fatty acid concentration during the 6 mo before the farm visit and were categorized as high de novo (HDN; 24.61 ± 0.75 g/100 g of fatty acids, mean ± standard deviation; n = 19) or low de novo (LDN; 23.10 ± 0.88 g/100 g of fatty acids; n = 20). Farms were visited once in February, March, or April 2015 and evaluated based on management and facility design known to affect cow behavior, physical and chemical characteristics of the diet, and ration formulation and forage analyses obtained from the farm's nutritionist. We observed no differences between HDN and LDN farms in farm size, time away from the pen for milking, days in milk, or body condition score. We detected no differences between HDN and LDN farms in milk fat or true protein yield; however, milk fat and protein content and de novo fatty acid yield per day were higher for HDN farms, as was gross income per unit of milk sold. High de novo farms tended to be more likely to deliver fresh feed twice versus once per day, have a freestall stocking density ≤110%, and provide ≥46 cm of feed bunk space per cow. We observed no detectable differences in forage quality or ration dry matter, crude protein, or starch content. However, ether extract was lower and physically effective neutral detergent fiber was higher for HDN farms. Feeding management, stocking density, dietary ether extract content, and the physical characteristics of the diet are related to de novo fatty acid, fat, and protein concentration in bulk tank milk from high-producing Holstein dairy farms.

Ether in the developing world: rethinking an abandoned agent.

BACKGROUND: The first true demonstration of ether as an inhalation anesthetic was on October 16, 1846 by William T.G. Morton, a Boston dentist. Ether has been replaced completely by newer inhalation agents and open drop delivery systems have been exchanged for complicated vaporizers and monitoring systems. Anesthesia in the developing world, however, where lack of financial stability has halted the development of the field, still closely resembles primitive anesthetics. DISCUSSION: In areas where resources are scarce, patients are often not given supplemental intraoperative analgesia. While halothane provides little analgesia, ether provides excellent intra-operative pain control that can extend for several hours into the postoperative period. An important barrier to the widespread use of ether is availability. With decreasing demand, production of the inexpensive inhalation agent has fallen. Ether is inexpensive to manufacture, and encouraging increased production at a local level would help developing nations to cut costs and become more self-sufficient.

The outlook of physician histories: J. Marion Sims and 'The Discovery of Anaesthesia'.

The fact that doctors have a long tradition of writing medical history to interpret and direct their profession is well established. But readers (particularly modern physician readers) can also understand physician-authored histories as offering commentary and analysis of the world beyond medicine. In this essay, we offer a reading (perhaps a modern one) of J. Marion Sims's 1877 article, 'The Discovery of Anaesthesia' which exemplifies the stance of looking both inward and outward from the medical field. We begin by discussing Sims, including the complicated legacy he left as a physician. Next, we review late 19th-century history with a focus on Reconstruction. Finally, we show how the modern reader can use Sims's article both to trace the first use of ether and nitrous oxide for surgical anaesthesia and to provide a window into the 19th-century medical profession and the post-Civil War period. Through this study, we hope to show how to read both medicine and the world around it in physician histories.