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31.
Transport of chemical and microbial compounds from known wastewater discharges: potential for use as indicators of human fecal contamination 总被引:3,自引:0,他引:3
Glassmeyer ST Furlong ET Kolpin DW Cahill JD Zaugg SD Werner SL Meyer MT Kryak DD 《Environmental science & technology》2005,39(14):5157-5169
The quality of drinking and recreational water is currently (2005) determined using indicator bacteria. However, the culture tests used to analyze forthese bacteria require a long time to complete and do not discriminate between human and animal fecal material sources. One complementary approach is to use chemicals found in human wastewater, which would have the advantages of (1) potentially shorter analysis times than the bacterial culture tests and (2) being selected for human-source specificity. At 10 locations, water samples were collected upstream and at two successive points downstream from a wastewaster treatment plant (WWTP); a treated effluent sample was also collected at each WWTP. This sampling plan was used to determine the persistence of a chemically diverse suite of emerging contaminants in streams. Samples were also collected at two reference locations assumed to have minimal human impacts. Of the 110 chemical analytes investigated in this project, 78 were detected at least once. The number of compounds in a given sample ranged from 3 at a reference location to 50 in a WWTP effluent sample. The total analyte load at each location varied from 0.018 microg/L at the reference location to 97.7 microg/L in a separate WWTP effluent sample. Although most of the compound concentrations were in the range of 0.01-1.0 microg/L, in some samples, individual concentrations were in the range of 5-38 microg/L. The concentrations of the majority of the chemicals present in the samples generally followed the expected trend: they were either nonexistent or at trace levels in the upstream samples, had their maximum concentrations in the WWTP effluent samples, and then declined in the two downstream samples. This research suggests that selected chemicals are useful as tracers of human wastewater discharge. 相似文献
32.
Islam Z Capatina D Ruff JP Das RK Trakhtenberg E Nojiri H Narumi Y Welp U Canfield PC 《The Review of scientific instruments》2012,83(3):035101
We present a pulsed-magnet system that enables x-ray single-crystal diffraction in addition to powder and spectroscopic studies with the magnetic field applied on or close to the scattering plane. The apparatus consists of a single large-bore solenoid, cooled by liquid nitrogen. A second independent closed-cycle cryostat is used for cooling samples near liquid helium temperatures. Pulsed magnetic fields close to ~30 T with a zero-to-peak-field rise time of ~2.9 ms are generated by discharging a 40 kJ capacitor bank into the magnet coil. The unique characteristic of this instrument is the preservation of maximum scattering angle (~23.6°) on the entrance and exit sides of the magnet bore by virtue of a novel double-funnel insert. This instrument will facilitate x-ray diffraction and spectroscopic studies that are impractical, if not impossible, to perform using split-pair and narrow-opening solenoid magnets. Furthermore, it offers a practical solution for preserving optical access in future higher-field pulsed magnets. 相似文献
33.
Kazuo Tsubota Stephen C. Pflugfelder Zuguo Liu Christophe Baudouin Hyo Myung Kim Elisabeth M. Messmer Friedrich Kruse Lingyi Liang Jimena Tatiana Carreno-Galeano Maurizio Rolando Norihiko Yokoi Shigeru Kinoshita Reza Dana 《International journal of molecular sciences》2020,21(23)
Over the past decades, the number of patients with dry eye disease (DED) has increased dramatically. The incidence of DED is higher in Asia than in Europe and North America, suggesting the involvement of cultural or racial factors in DED etiology. Although many definitions of DED have been used, discrepancies exist between the various definitions of dry eye disease (DED) used across the globe. This article presents a clinical consensus on the definition of DED, as formulated in four meetings with global DED experts. The proposed new definition is as follows: “Dry eye is a multifactorial disease characterized by a persistently unstable and/or deficient tear film (TF) causing discomfort and/or visual impairment, accompanied by variable degrees of ocular surface epitheliopathy, inflammation and neurosensory abnormalities.” The key criteria for the diagnosis of DED are unstable TF, inflammation, ocular discomfort and visual impairment. This definition also recommends the assessment of ocular surface epitheliopathy and neurosensory abnormalities in each patient with suspected DED. It is easily applicable in clinical practice and should help practitioners diagnose DED consistently. This consensus definition of DED should also help to guide research and clinical trials that, to date, have been hampered by the lack of an established surrogate endpoint. 相似文献
34.
N‐Arylsulfonyl Indolines as Retinoic Acid Receptor‐Related Orphan Receptor γ (RORγ) Agonists 下载免费PDF全文
Dr. Christelle Doebelin Rémi Patouret Ruben D. Garcia‐Ordonez Dr. Mi Ra Chang Dr. Venkatasubramanian Dharmarajan Dana S. Kuruvilla Scott J. Novick Li Lin Dr. Michael D. Cameron Dr. Patrick R. Griffin Dr. Theodore M. Kamenecka 《ChemMedChem》2016,11(23):2607-2620
The nuclear retinoic acid receptor‐related orphan receptor γ (RORγ; NR1F3) is a key regulator of inflammatory gene programs involved in T helper 17 (TH17) cell proliferation. As such, synthetic small‐molecule repressors (inverse agonists) targeting RORγ have been extensively studied for their potential as therapeutic agents for various autoimmune diseases. Alternatively, enhancing TH17 cell proliferation through activation (agonism) of RORγ may boost an immune response, thereby offering a potentially new approach in cancer immunotherapy. Herein we describe the development of N‐arylsulfonyl indolines as RORγ agonists. Structure–activity studies reveal a critical linker region in these molecules as the major determinant for agonism. Hydrogen/deuterium exchange coupled to mass spectrometry (HDX‐MS) analysis of RORγ–ligand complexes help rationalize the observed results. 相似文献
35.
Mohammad Dana Mohammad Amin Sobati Shahrokh Shahhosseini Aminreza Ansari 《中国化学工程学报》2020,28(5):1384-1396
A continuous-flow ultrasound-assisted oxidative desulfurization(UAOD) of partially hydro-treated diesel has been investigated using hydrogen peroxide-formic acid as simple and easy to apply oxidation system. The effects of different operating parameters of oxidation stage including residence time(2–24 min), formic acid to sulfur molar ratio(10–150), and oxidant to sulfur molar ratio(5–35) on the sulfur removal have been studied using response surface methodology(RSM) based on Box–Behnken design. Considering the operating costs of the continuous-flow oxidation stage including chemical and electrical energy consumption, the appropriate values of operating parameters were selected as follows: residence time of 16 min, the formic acid to sulfur molar ratio of 54.47, and the oxidant to sulfur molar ratio of 8.24. In these conditions, the sulfur removal and the volume ratio of the hydrocarbon phase to the aqueous phase were 86.90% and 4.34, respectively. By drastic reduction in the chemical consumption in the oxidation stage, the volume ratio of the hydrocarbon phase to the aqueous phase was increased up to 10. Therefore, the formic acid to sulfur molar ratio and the oxidant to sulfur molar ratio were obtained 23.64 and 3.58, respectively, which lead to sulfur removal of 84.38% with considerable improvements on the operating cost of oxidation stage in comparison with the previous works. 相似文献
36.
Mihaela Badea Rodica Olar Dana Marinescu Gina Vasile Bogdan Jurca Augustin M. Madalan Marius Andruh 《Inorganic chemistry communications》2009,12(6):555-557
The reaction between NiCO3 · Ni(OH)2, acrylic acid and ethylenediamine in a 2:4:1 molar ratio affords the binuclear complex, [Ni2(EDDP)2(H2O)2] · 2H2O 1. The organic ligand, EDDP2? (the dianion of the ethylenediamine-N,N-dipropionic acid ligand), results from the addition of one amine group to the carbon–carbon double bonds of two acrylato ions. The crystal structure of 1 consists of neutral centrosymmetric entities, with the nickel ions connected by two carboxylato groups, each one acting as a monoatomic bridge. The intramolecular Ni?Ni distance is 3.212 Å. The metal ions exhibit an octahedral geometry. The cryomagnetic investigation of 1 reveals an antiferromagnetic coupling of the nickel(II) ions (J = ?21.8 cm?1, H = ?JSNi1SNi2). 相似文献
37.
Mostofa Shamim Somnath Sinhamahapatra Jahangir Hossain Sayan Lahiri Kausik Dana 《Ceramics International》2018,44(2):1868-1874
The mechanistic pathway of MgO-Al2O3 reaction in solid state to form MgAl2O4 spinel was investigated to correlate the kinetic parameters with ratio of reactants (MgO:Al2O3) and with the presence of a doping agent, TiO2. The time-temperature-expansion data of oxide compacts was analyzed using several model free analyses and model based (linear and non-linear) kinetic algorithms. These indicated that spinel formation process can be best described by single step with n-dimensional Avrami equation for every MgO:Al2O3 ratio, irrespective of titania dopant. The activation energy (Ea) of the process was proportional to % spinel formed in each system and validated with quantitative XRD analysis. The higher value of Avrami coefficient (n) in 90 wt% Al2O3 compositions has been explained with geometric considerations of powder packing. Incorporations of 1% TiO2 in the MgO: Al2O3 oxide compact did not markedly affect the reaction model, frequency factor and Activation energy. 相似文献
38.
Effect of Alumina Reactivity on the Densification and Properties of Al2O3–Cr2O3 Refractories 下载免费PDF全文
Mithun Nath Vakiti Pradeep Reddy Somnath Sinhamahapatra Kausik Dana Arup Ghosh Himansu Sekhar Tripathi 《International Journal of Applied Ceramic Technology》2015,12(3):608-613
Alumina‐chrome (Al2O3–Cr2O3) refractories with Al2O3:Cr2O3 molar ratio 1:1 were synthesized in the temperature range of 1400–1700°C by conventional solid–oxide reaction route. The effect of different aluminas (viz., hydrated and calcined) on the densification, microstructure, and properties of Al2O3–Cr2O3 refractories was investigated without changing the Cr2O3 source. The starting materials were analyzed to determine the chemical composition, mineralogy, density, surface area, and particle size. Sintered materials were characterized in terms of densification, phase assemblage, and mechanical strength at room temperature and at higher temperatures. Microstructural evolution at different sintering temperature was correlated with sintering characteristics. It can be concluded that the Al2O3–Cr2O3 refractories prepared with hydrated alumina as Al2O3 source show better densification and hot mechanical strength than corresponding calcined variety. 相似文献
39.
Influence of solute type and concentration on ice scaling in fluidized bed ice crystallizers 总被引:1,自引:0,他引:1
During crystallization of ice from aqueous solutions, ice crystals exhibit a marked tendency to adhere to the cooled heat exchanger wall resulting in the formation of an insulating ice layer, often referred to as ice scaling. A promising method to avoid ice scaling is the application of a solid-liquid fluidized bed heat exchanger in which fluidized steel particles remove the ice crystals from the walls. This paper presents experiments with a single-tube fluidized bed heat exchanger in which ice crystals were produced from aqueous solutions of various solutes with varying concentrations. The experiments reveal that ice scaling is only prevented when a certain temperature difference between wall and solution is not exceeded. This transition temperature difference appears to increase approximately linearly with the solute concentration and is higher in aqueous solutions with low diffusion coefficients. The observed phenomena are explained by the hypothesis that ice scaling is only prevented when the mass transfer controlled growth rate of ice crystals on the wall does not exceed the scale removal rate induced by the fluidized steel particles. In conclusion, a model based on these physical phenomena is proposed to predict ice scaling in fluidized bed heat exchangers. 相似文献
40.
This study examined the individual and combined effects of exposure to positive Latino exemplars and prototypes in the media on White audience members' attitudes about and judgments regarding Latinos in society. Although it was expected that exposure to these favorable models would promote positive evaluations of Latinos among White consumers, the extent to which one mode of presentation could be privileged in the production of more beneficial outcomes was uncertain based on existing research. These results cautiously indicate that while prototypes may offer some advantages in terms of reducing stereotyping, both exemplar‐ and prototype‐based characterizations of positive race‐related media content (alone and in combination) can positively influence consumers' perceptions of target racial/ethnic groups. 相似文献