Biofilm development in micro-irrigation emitters for wastewater reuse

Laboratory experiments were carried out to investigate bioclogging on three types of online emitters using synthetic wastewater filtered at 10 μm (COD = 200 mg L^?1). The three types of emitters were as follows: non-pressure-compensating emitters delivering 2 L h^?1 (NPC2), non-pressure-compensating emitters delivering 4 L h^?1 (NPC4) and pressure-compensating emitters delivering 2.2 L h^?1 (PC). They were plugged on two parallel pipe diameters (16 and 20 mm). Emitter performance was followed by flow rate measurements. The results showed that PC emitters seemed to be more sensitive to clogging than NPC emitters. Biofilm was observed mainly on NPC flow paths and PC membranes; its presence was also confirmed by the assessment of different water quality parameters such as total organic carbon and pH. Experimental results compared with a model designed with computational fluid dynamics Software (ANSYS Fluent^®) showed relations between biofilm development and velocity distribution on NPC flow paths. Finally, pipe diameter also appeared to be a parameter inducing emitter clogging.     

Usefulness of trunk diameter variations as continuous water stress indicators of pomegranate (Punica granatum) trees

Pomegranate trees (Punica granatum L.) is a deciduous fruit tree included in the so-called group of minor fruit tree species, not widely grown but of some importance in the south east of Spain. Pomegranate trees are considered as a culture tolerant to soil water deficit. However, very little is known about pomegranate orchard water management. The objective of this research was to asses the feasibility of using trunk diameter variation (TDV) indexes, obtained by means of LVDT sensors, as a plant water stress indicators for pomegranate trees. The experiment was carried out with mature trees grown in the field under three irrigation regimes: control well watered trees; trees continuously deficit irrigated at 50% of the control regime (SDI); and trees that had a summer water stress cycle being irrigated at 25% of the control rates only in July and August (RDI). The seasonal variations of maximum diurnal trunk shrinkage (MDS) and trunk growth rates (TGR) were compared with midday stem water potential (Ψstem) measurements. During the course of the entire season, control trees maintained lower MDS values than the SDI ones. In the RDI treatment, as water restrictions began, there was a slow increase in MDS, in correspondence with a decrease in Ψstem. When water was returned at full dosage, the RDI quickly recovered to MDS and Ψstem values similar to the control. However, lower MDS for a given Ψstem values were observed as the season advanced. The magnitude of differences between well watered and deficit irrigated trees was much larger in the case of MDS than for Ψstem. However, the tree-to-tree variability of the MDS readings was more than four times higher than for Ψstem; average coefficient of variation of 7.5 and 36% for Ψstem and MDS, respectively. On the other hand, TGR did not clearly reflect differences in tree water status. Overall, results reported indicated that MDS is a good indicator of pomegranate tree water status and it can be further used for managing irrigation. However, the seasonal changes in the MDS-Ψstem relationship should be taken into account when attempting to use threshold MDS values for scheduling irrigation.     

Stem and head reaction of winter wheat cultivars to artificial inoculation by Microdochium nivale under controlled environment and field conditions

Summary Experiments to assess variation in the resistance of winter wheat to infection by Microdochium nivale were conducted over two consecutive years. Resistance was evaluated using an agar disk technique to reproduce stem lesions and by spraying a conidial suspension to reproduce head blight symptoms. Significant variation for stem reaction measured as stem lesion area (SLA), and head reaction measured as disease severity (DS) was found in the 33 winter wheat genotypes tested. Data obtained over two years in controlled environment conditions were significantly correlated (r=0.713 for SLA and r=0.738 for DS), whereas field data showed a significant genotype x year interaction for disease severity. Quantitative variation for susceptibility to stem and head infection by M. nivale was found among the 33 genotypes tested. The majority of genotypes expressed moderate susceptibility, with cultivar Goupil being very susceptible to both stem and head infection, and the remainder, Renan, Arminda, Munstertaler and Saint-Johann were the most resistant. Resistance to stem and head to M. nivale were not correlated (r=0.358).     

Conformational interpretation of vescalagin and castalagin physicochemical properties

Vescalagin and castalagin are two diastereoisomers. The variability of their principal physicochemical properties, compared with their small structural differences, suggests important conformational variations. This study shows, experimentally, that vescalagin has a greater effect on polarity, oxidizability in solution, and thermodegradability than castalagin. Conformational analysis by molecular mechanics demonstrated that vescalagin was more hydrophilic and was more reactive to electrophilic reagents than castalagin. Experimental results were thus explained and demonstrated the distinct behaviors of vescalagin and castalagin. These results were attributed to the C1 position of the two compounds because vescalin and castalin have comparable characteristics. Experimental data were confirmed and interpreted by molecular mechanics. This work represents one of the first attempts to correlate conformation and the properties of phenolic compounds. This step constitutes a predictive method for the pharmacology or chemistry of new compounds.     

Impact of concentration of ellagitannins in oak wood on their levels and organoleptic influence in red wine

Some wood substances such as ellagitannins can be extracted during wine aging in oak barrels. The level of these hydrolyzable tannins in wine depends of some parameters of oak wood. Their impact on the organoleptic perception of red wine is poorly known. In our research, oak staves were classified in three different groups according to their level of ellagitannins estimated by NIRS (near infrared spectroscopy) online procedure (Oakscan). First, the ellagitannin level and composition were determine for each classified stave and an excellent correlation between the NIRS classification (low, medium and high potential level of ellagitannin) and the ellagitannin content estimated by HPLC-UV was found. Each different group of NIRS classified staves was then added to red wine during its aging in a stainless tank, and the extraction and evolution of the ellagitannins were monitored. A good correlation between the NIRS classification and the concentration of ellagitannins in red wine aging in contact with the classified staves was observed. The influence of levels of ellagitannins on the resulting wine perception was estimated by a trained judge's panel, and it reveals that the level of ellagitannins in wine has an impact on the roundness and amplitude of the red wine.     

Competition for Oxygen Among Oxidative Systems During Bread Dough Mixing: Consequences of Addition of Glucose Oxidase and Lipoxygenase on Yeasted Dough Rheology

The effect on O₂ uptake during the mixing of yeasted dough, either unsupplemented or supplemented with glucose oxidase (GOX), horsebean flour (HB), soybean flour (SB), or combinations thereof, was studied using an airtight mixer. Two wheat flours with a low (flour A) and a high (flour B) content of free polyunsaturated fatty acids were used. Addition of HB or SB provokes a similar increase of O₂ uptake for both wheat flours, whereas addition of GOX causes a larger increase for flour A than for flour B. When the wheat flours were supplemented with HB or SB, addition of GOX caused a small but significant increase of O₂ uptake for flour A. This increase was not observed for flour B. The mixing tolerance of dough A, determined with the Chopin Consistograph, is increased by GOX addition. However, this effect is less pronounced when flour A is supplemented with HB or SB. Similarly, the relaxation index of dough B is decreased by GOX addition, but the decrease is less distinct in the presence of HB or SB. These results can be explained by a competition among yeast, GOX, and lipoxygenases (present in wheat, HB, and SB flours) for the O₂ uptake by dough, which likely decreases the amount of hydrogen peroxide produced by GOX during dough mixing. This competition for O₂ consequently also modifies the rheological properties of dough.     

What are the limits of the drilosphere? An incubation experiment using Metaphire posthuma

The near infrared reflectance spectroscopy (NIRS) method was used in the present study to compare earthworm-made soil aggregates to aggregates found in the surrounding bulk soil. After initially assessing the daily cast production of Metaphire posthuma, boxes with soil incubated with M. posthuma and control soils were subjected to wetting in order to reorganize the soil structure. After two months of incubation, soil aggregates produced by earthworms (casts and burrows), soil aggregates that were appeared to be unaffected by earthworms (bulk soil without visible trace of earthworm bioturbation from the earthworm treatment) and soil aggregates that were entirely unaffected by earthworms (control – no earthworm – treatment) were sampled and their chemical signatures analyzed by NIRS. The production of below-ground and surface casts reached 14.9 g soil g worm^?1 d^?1 and 1.4 g soil g worm^?1 d^?1, respectively. Soil aggregates from the control soils had a significantly different NIRS signature from those sampled from boxes with earthworms. However, within the earthworm incubation boxes the NIRS signature was similar between cast and burrow aggregates and soil aggregates from the surrounding bulk soil. We conclude that the high cast production by M. posthuma and the regular reorganization of the soil structure by water flow in and through the soil lead to a relatively homogenous soil structure. Given these results, we question the relevance of considering the bulk soil that has no visible activity of earthworm activity as a control to determine the effect of earthworms on soil functioning.     

Pyogenic bacterial infections in humans with MyD88 deficiency

MyD88 is a key downstream adapter for most Toll-like receptors (TLRs) and interleukin-1 receptors (IL-1Rs). MyD88 deficiency in mice leads to susceptibility to a broad range of pathogens in experimental settings of infection. We describe a distinct situation in a natural setting of human infection. Nine children with autosomal recessive MyD88 deficiency suffered from life-threatening, often recurrent pyogenic bacterial infections, including invasive pneumococcal disease. However, these patients were otherwise healthy, with normal resistance to other microbes. Their clinical status improved with age, but not due to any cellular leakiness in MyD88 deficiency. The MyD88-dependent TLRs and IL-1Rs are therefore essential for protective immunity to a small number of pyogenic bacteria, but redundant for host defense to most natural infections.     

Seasonal flows on warm Martian slopes

Water probably flowed across ancient Mars, but whether it ever exists as a liquid on the surface today remains debatable. Recurring slope lineae (RSL) are narrow (0.5 to 5 meters), relatively dark markings on steep (25° to 40°) slopes; repeat images from the Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment show them to appear and incrementally grow during warm seasons and fade in cold seasons. They extend downslope from bedrock outcrops, often associated with small channels, and hundreds of them form in some rare locations. RSL appear and lengthen in the late southern spring and summer from 48°S to 32°S latitudes favoring equator-facing slopes, which are times and places with peak surface temperatures from ~250 to 300 kelvin. Liquid brines near the surface might explain this activity, but the exact mechanism and source of water are not understood.     

Effect of a polyphenols-enriched chardonnay white wine in diabetic rats

A Chardonnay white wine enriched in polyphenols was obtained by modification of winemaking and characterized by its enrichment in total polyphenolic content (1346 mg/L as compared to 316 mg/L for traditional Chardonnay) and in various individual polyphenols (catechin, epicatechin, procyanidins dimers B1-B4, gallic acid, cafeic acid, and caftaric acid), as determined from HPLC coupled to a diode array detector. The polyphenols-enriched white wine (W) or its ethanol-free derivative (EFW) was then administered by gavage (10 mL/kg, twice a day) for 6 weeks to rats that have been rendered diabetic by a single iv injection of streptozotocin (55 mg/kg). Treatments had no effect on the symptoms associated with hyperglycemia. However, while a reduction in plasma antioxidant capacity was associated with the diabetic state, administration of W or EFW restored plasma antioxidant capacities to a level not significantly different from that of nondiabetic control animals. In addition, the effect of both treatments was manifested by the enlargement of mesenteric arteries, as determined by quantitative histomorphometry. In summary, our study indicates that white wine, when enriched in polyphenols, is able to induce ethanol-independent in vivo effects in a model of insulin-deficient diabetes characterized by a major oxidative stress.