Contribution of treated wastewater to the microbiological quality of Seine River in Paris

Urban part of Seine River serving as drinking water supply in Paris can be heavily contaminated by Cryptosporidium spp. and Giardia duodenalis. In the absence of agricultural practice in this highly urbanized area, we investigated herein the contribution of treated wastewater to the microbiological quality of this river focusing on these two parasites. Other microorganisms such as faecal bacterial indicators, enteroviruses and oocysts of Toxoplasma gondii were assessed concurrently. Raw wastewaters were heavily contaminated by Cryptosporidium and Giardia (oo)cysts, whereas concentrations of both protozoa in treated wastewater were lower. Treated wastewater, flowed into Seine River, had a parasite concentration closed to the one found along the river, in particular at the entry of a drinking water plant (DWP). Even if faecal bacteria were reliable indicators of a reduction in parasite concentrations during the wastewater treatment, they were not correlated to protozoal contamination of wastewater and river water. Oocysts of T. gondii were not found in both raw and treated wastewater, or in Seine River. Parasitic contamination was shown to be constant in the Seine River up to 40 km upstream Paris. Altogether, these results strongly suggest that treated wastewater does not contribute to the main parasitic contamination of the Seine River usually observed in this urbanized area.     

Influence of algal and bacterial particulate organic matter on benzo[a]pyrene bioaccumulation in Daphnia magna

In order to better asses the influence of organic matter on the bioavailability of hydrophobic organic contaminants, the effect of algae and POM of bacterial origin on the bioaccumulation of benzo[a]pyrene in Daphnia magna was evaluated. The bioaccumulation was monitored with increasing concentrations of particulate organic matter (POM) and dissolved organic matter (DOM). In all experiments, the presence of POM greatly reduced the bioaccumulation of benzo[a]pyrene. The reduction was more pronounced in the presence of algae, for which we observed a 99%-reduction effect in the presence of 6 x10 (5) cell/mL (equivalent to 5.3 mg C/L). The bioaccumulation of benzo[a]pyrene was decreased by 49% by organic matter of bacterial origin at 4.7 mg C/L. Assuming that benzo[a]pyrene was partitioned between water, DOM and POM and supposing that D. magna accumulated free benzo[a]pyrene via respiration and POM-bond benzo[a]pyrene via ingestion, bioaccumulation data allowed to estimate the dietary uptake rate of benzo[a]pyrene as well as partitioning coefficients K(POC) and K(DOC). Despite the ingestion of contaminated particles, we could not observe any dietary uptake of benzo[a]pyrene in daphnids. We verified, as usually supposed, that the bioaccumulation of benzo[a]pyrene to D. magna occurs mainly via direct contact. Very high partitioning coefficients (log K(POC) between 5.2 and 6.2) were estimated. This study pointed out the great influence of biogenic organic matter on the fate and the bioavailability of benzo[a]pyrene in aquatic ecosystems.     

Quantitative aerobiologic analysis of an influenza human challenge-transmission trial

Despite evidence that airborne transmission contributes to influenza epidemics, limited knowledge of the infectiousness of human influenza cases hinders pandemic preparedness. We used airborne viral source strength and indoor CO₂ monitoring from the largest human influenza challenge-transmission trial (EMIT: Evaluating Modes of Influenza Transmission, ClinicalTrials.gov number NCT01710111) to compute an airborne infectious dose generation rate q = 0.11 (95% CI 0.088, 0.12)/h and calculate the quantity of airborne virus per infectious dose σ = 1.4E + 5 RNA copies/quantum (95% CI 9.9E + 4, 1.8E + 5). We then compared these calculated values to available data on influenza airborne infectious dose from several previous studies, and applied the values to dormitory room environments to predict probability of transmission between roommates. Transmission risk from typical, moderately to severely symptomatic influenza cases is dramatically decreased by exposure reduction via increasing indoor air ventilation. The minority of cases who shed the most virus (ie, supershedders) may pose great risk even in well-ventilated spaces. Our modeling method and estimated infectiousness provide a ground work for (a) epidemiologic studies of transmission in non-experimental settings and (b) evaluation of the extent to which airborne exposure control strategies could limit transmission risk.     

Effect of Magnetic Field Dynamics on the Copper‐Constantan Thermocouple Performance

Abstract

This paper presents some results of experimental research addressing the influence of magnetic field dynamics on the copper‐constantan thermocouple performance. There are challenges in measuring temperature by thermocouples in a time‐dependent magnetic field. Although there is considerable experience on the effect of a static magnetic field, there is a lack of awareness of the outcome of a varying field on thermocouple performance. We measured the accuracy of the thermocouple response in an alternating magnetic field for various operational parameters: frequency of the magnetic field, geometry, and length of the thermocouple wire in the field, and magnetic field strength. The effect of each of the operational parameters is discussed. Test results of temperature profile measure by a copper‐constantan thermocouple in a varying magnetic field system that was used in a room temperature magnetic refrigeration test bed are demonstrated.     

Electron microscopy localization and characterization of functionalized composite organic-inorganic SERS nanoparticles on leukemia cells

We demonstrate the use of electron microscopy as a powerful characterization tool to identify and locate antibody-conjugated composite organic-inorganic nanoparticle (COINs) surface enhanced Raman scattering (SERS) nanoparticles on cells. U937 leukemia cells labeled with antibody CD54-conjugated COINs were characterized in their native, hydrated state using wet scanning electron microscopy (SEM) and in their dehydrated state using high-resolution SEM. In both cases, the backscattered electron (BSE) detector was used to detect and identify the silver constituents in COINs due to its high sensitivity to atomic number variations within a specimen. The imaging and analytical capabilities in the SEM were further complemented by higher resolution transmission electron microscopy (TEM) images and scanning Auger electron spectroscopy (AES) data to give reliable and high-resolution information about nanoparticles and their binding to cell surface antigens.     

Polymerization of α-olefins and Hydrogenolysis of the Resulting Polyolefins with Hafnium Hydrides Supported on Silica

The reaction of Hf(CH₂ tBu)₄ with a silica surface treated at 800 °C affords the unique single site (≡SiO)Hf(CH₂ tBu)_3, 1, ((≡SiO) = silica surface ligand). Reaction of 1, with dihydrogen at temperatures (θ) ranging from 100 °C to 250 °C leads to different surface hydrides. At θ ≤ 100 °C, there is formation of [(≡SiO)Hf(CH₂ tBu)(H)₂], 2. For 100 ≤ θ ≤ 200 °C, 2 affords, [(≡SiO)₂Hf(H)₂], 3, and [(≡SiO)₃SiH]. For 150 ≤ θ ≤ 250 °C, 3, is totally converted into [(≡SiO)₃Hf(H)], 4, and [(≡SiO)₂Si(H)₂]. These different surface hafnium hydrides 2–4, which are obtained simultaneously but in various proportions were referred to as [Hf]_θ–H, (θ = 75, 100, 125, 150 and 250 °C). [Hf]₁₅₀–H is the most active catalyst in α olefin (ethylene, propene, isobutylene) polymerization at 25 °C and in polyolefin depolymerization at 150 °C under H₂ atmosphere. Although, there is a clear correlation between the catalytic activity both in polymerization and in depolymerization, and the amount of 3 and 4, it is not possible to establish which between the mono and the bis-hydride is the most active.     

Modeling nitrous oxide emissions from tile-drained winter wheat fields in Central France

Modeling nitrous oxide (N₂O) emissions from agricultural soils is still a challenge due to influences of artificial management practices on the complex interactions between soil factors and microbial activities. The aims of this study were to evaluate the process-based DeNitrification-DeComposition (DNDC, version 9.5) model and modified non-linear empirical Nitrous Oxide Emission (NOE_V2) model with weekly N₂O flux measurements at eight sites cropped with winter wheat across a tile-drained landscape (around 30-km²) in Central France. Adjustments of the model default field capacity and wilting point and the optimum crop production were necessary for DNDC95 to better match soil water content and crop biomass yields, respectively. Multiple effects of varying soil water and nitrate contents on the fraction of N₂O emitted through denitrification were added in NOE_V2. DNDC95 and NOE_V2 successfully predicted background N₂O emissions and fertilizer-induced emission peaks at all sites during the experimental period but overestimated the daily fluxes on the sampling dates by 54 and 25 % on average, respectively. Cumulative emissions were slightly overestimated by DNDC95 (4 %) and underestimated by NOE_V2 (15 %). The differences between evaluations of both models for daily and cumulative emissions indicate that low frequency measurements induced uncertainty in model validation. Nonetheless, our validations for soil water content with daily resolution suggest that DNDC95 well represented the effect of tile drainage on soil hydrology. The model overestimated soil ammonium and nitrate contents mostly due to incorrect nitrogen partitioning when urea ammonium nitrate solution was applied. The performance of the model would be improved if DNDC included the canopy interception and foliar nitrogen uptake when liquid fertilizer was sprayed over the crops.     

Rh–Fe/Ca–Al2O3: A Unique Catalyst for CO-Free Hydrogen Production in Low Temperature Ethanol Steam Reforming

Low temperature ethanol steam reforming (ESR) was studied over a series of 1 wt% Rh–x % Fe catalysts with various Fe loading (x = 0–10 wt%) and on different supports (Ca–Al₂O₃, SiO₂ and ZrO₂). The results show that close interaction between Rh and Fe is required to reduce the CO selectivity to almost negligible values. In addition, Rh–Fe supported on Ca–Al₂O₃ exhibits the best performance in terms of CO selectivity and hydrogen yield as compared to other supports. Characterization by XPS and XANES indicates the presence of Fe_xO_y species upon reduction, resulting in the formation of coordinatively unsaturated ferrous (CUF) active sites along the Rh–Fe_xO_y interface. These CUF sites promote water–gas shift reaction during low temperature ESR. Temperature programmed oxidation and Raman spectroscopy of spent catalysts also indicate that the addition of iron oxide reduces coke deposition and forms more reactive coke. Hence, the catalyst lifespan is significantly extended.     

Legume,cropping intensity,and N-fertilization effects on soil attributes and processes from an eight-year-old semiarid wheat system

In the North American northern Great Plains (NGP), legumes are promising summer fallow replacement/cropping intensification options that may decrease dependence on nitrogen (N) fertilizer in small grain systems and mitigate effects of soil organic matter (SOM) losses from summer fallow. Benefits may not be realized immediately in semiarid conditions though, and longer-term effects of legumes and intensified cropping in this region are unclear, particularly in no-till systems. We compared effects of four no-till wheat (Triticum aestivum L.) cropping systems–summer fallow–wheat (F–W), continuous wheat (CW), legume green manure (pea, Pisum sativum L.)—wheat (LGM–W), and pea–wheat (P–W)—on select soil attributes in an 8-year-old rotation study, and N fertilizer effects on C and N mineralization on a duplicate soil set in a laboratory experiment. We analyzed potentially mineralizable carbon and nitrogen (PMC and PMN) and mineralization trends with a nonlinear model, microbial biomass carbon (MB-C), and wet aggregate stability (WAS). Legume-containing systems generally resulted in higher PMC, PMN, and MB-C, while intensified systems (CW and P–W) had higher WAS. Half-lives of PMC were shortest in intensified systems, and were longest in legume systems (LGM–W and P–W) for PMN. Nitrogen addition depressed C and N mineralization, particularly in CW, and generally shortened the half-life of mineralizable C. Legumes may increase long-term, no-till NGP agroecosystem resilience and sustainability by (1) increasing the available N-supply (~26–50 %) compared to wheat-only systems, thereby reducing the need for N fertilizer for subsequent crops, and (2) by potentially mitigating negative effects of SOM loss from summer fallow.     

ANN Analysis of a Roller Compaction Process in the Pharmaceutical Industry

Dry granulation via a roller compactor was simulated based on the artificial neural network (ANN) methodology. Two process parameters, including roll force and screw speed, were considered as input of the simulation whereas ribbon density was considered as output. Experimental work was carried out using an industrial‐scale roller compactor. The results showed an excellent agreement between simulation and experiments. The findings were compared as well with the results obtained in a previous study employing the Johanson model, which is the predominant model for the simulation of a roller compaction process. The overall deviation observed for the developed ANN model was found to be significantly improved in comparison with the deviation obtained for the Johanson model. The results demonstrated a very good capability and robustness of the developed ANN model in design and optimization of the roller compaction process.