Runaway electron beams in the gas discharge for UV nitrogen laser excitation

The review of the methods for obtaining the runaway electron beams in the gas discharge is performed. The new method is offered, using which the beam is first formed in a narrow gap (∼1 mm) between the cathode and the grid and then it is accelerated by the field of the plasma column of the anomalous self-sustained discharge in the main gap (10–20 mm long). The electron beams with an energy of about 10 keV and current density of 10³ A/cm² at a molecular nitrogen pressure of up to 100 Torr have been obtained experimentally. The results of research of the UV nitrogen laser with an excitation via runaway electron beam and radiation of energy of ∼1 mJ are given. The UV nitrogen laser generation with the energy of ∼1 mJ has been obtained by the runaway electron beams.     

Moisture adsorption capacity and surface area as deduced from vapour pressure isotherms in relation to hygroscopic water of soils

Six calcareous and alluvial soil profiles differing in their texture, CaCO₃ and salinity were chosen from west and middle Nile Delta for the present study. The 1^st and 2^nd profiles from Borg El-Arab area were sandy loam in texture and > 30% CaCO₃, while the 3^rd and 4^th profiles (from Nubaria area) were sandy clay loam and < 30% CaCO₃. The 2^nd and 4^th profiles were taken from cultivated area with maize. The 5^th profile from Epshan area was non-saline clay alluvial soil and the 6^th from El-Khamsen was saline clay alluvial soil. The relation between soil moisture content (W%) and water vapour pressure (P/P _o) was established for the mentioned soils. Data showed that the specific surface area (S) values were 34–53 and 44–60 m²/g for calcareous soils of Borg El-Arab and Nubaria areas, 206–219 and 206–249 m²/g for non-saline and saline clay alluvial soils of Epshan and El-Khamsen areas, respectively. The corresponding values of the external specific surface area (S _e) were 16–21, 14–22, 72–86 and 92–112 m²/g. Submitting W _m+W _me as an adsorption boundary of moisture films (W _c) (where W _m is mono-adsorbed layer of water vapour on soil particles and W _me is the external mono-adsorbed layer), the maximum water adsorption capacity (W _a) was found to be W _c + W _me or W _m + 2W _me. It was ranged from 1.88 to 2.70%, 1.97 to 2.95%, 9.70–10.70% and 10.80 to 13.12% while the maximum hygroscopic water (M _H) values were 2.43–3.78%, 2.91–4.65%, 16–17% and 18.30–21.9% for the studied soil profiles respectively. The residual moisture content (θ _r) at pF 7 and P/P _o = 0 was ranged from 0.0005–0.0010%, 0.0007–0.0019% and 0.0043–0.0048% in Borg El-Arab, Nubaria and Epshan soil profiles, respectively. The inter-relations between the surface area and the hygroscopic moisture parameters of the soils under investigation were as follows Calcareous soils; W _m = 0.40 M _H, W _c = 0.55 M _H, W _a = 0.70 M _H, S = 14 M _H Non-saline soil; W _m = 0.35 M _H, W _c = 0.49 M _H, W _a = 0.63 M _H, S = 13 M _H Saline soil; W _m = 031 M _H, W _c = 0.45 M _H, W _a = 0.59 M _H, S = 12 M _H These relations give possibility to deduce the soil moisture adsorption capacities and specific surface area via maximum hygroscopic water, which can be obtained through the experimental determination of water vapor adsorption isotherms.     

The anode potential regulates bacterial activity in microbial fuel cells

The anode potential in microbial fuel cells controls both the theoretical energy gain for the microorganisms as the output of electrical energy. We operated three reactors fed with acetate continuously at a poised anode potential of 0 (R ₀), −200 (R ₋₂₀₀) and −400 (R ₋₄₀₀) mV versus Ag/AgCl and investigated the resulting bacterial activity. The anode potential had no influence on the start-up time of the three reactors. During a 31-day period, R ₋₂₀₀ produced 15% more charge compared to R ₀ and R ₋₄₀₀. In addition, R ₋₂₀₀ had the highest maximal power density (up to 199 W m⁻³ total anode compartment during polarization) but the three reactors evolved to the same power density at the end of the experimental period. During polarization, only the current of R ₋₄₀₀ levelled off at an anode potential of −300 mV versus Ag/AgCl. The maximum respiration rate of the bacteria during batch tests was also considerably lower for R ₋₄₀₀. The specific biomass activity however, was the highest for R ₋₄₀₀ (6.93 g chemical oxygen demand g⁻¹ biomass-volatile suspended solids (VSS) d⁻¹ on day 14). This lowered during the course of the experiment due to an increase of the biomass concentration to an average level of 578 ± 106 mg biomass-VSS L⁻¹ graphite granules for the three reactors. This research indicated that an optimal anode potential of −200 mV versus Ag/AgCl exists, regulating the activity and growth of bacteria to sustain an enhanced current and power generation.     

Measurements of the gas temperature in an oxygen plasma by spectroscopy of the O2( b 1Σ g+ ) → O2( X 3Σ g? ) transition

A method for measuring the gas temperature in an oxygen plasma by spectroscopy of the electronic transition from the O₂(b ¹Σ _g ⁺ , v = 0) metastable state of molecular oxygen into the O₂(X ³Σ _g ⁻ , v = 0) ground state is considered in detail. The method is verified experimentally for the plasma of dc glow discharge in pure oxygen. It is shown that the gas temperature can be determined by analyzing high-resolution spectra of the P branch of this transition, no matter whether its fine structure (^P P and ^P Q branches) is resolved or masked, provided that the rotational structure of the spectrum is resolved. The feasibility of the method proposed in 1999 by P. Maco and P. Veis for determining the gas temperature from the ratio between the intensity maxima of the R and P branches of the O₂(b ¹Σ _g ⁺ , v = 0) → O₂(X ³Σ _g ⁻ , v = 0) transition in a poorly resolved spectrum was studied experimentally. It is shown that, in order to use this method, it is necessary to know the spectrograph instrumental function. The effect of the spatial inhomogeneity of the temperature and concentration of O₂(b ¹Σ _g ⁺ ) molecules on the accuracy of integral (over the plasma volume) measurements of the gas temperature is investigated using spatially resolved spectroscopy of the O₂(b ¹Σ _g ⁺ , v = 0) → O₂(X ³Σ _g ⁻ , v = 0) transition. It is shown that precise measurements of the temperature require that the optical measurement system be thoroughly adjusted in order for the temperature and concentration of the emitting particles to vary insignificantly over the optically selected volume. Original Russian Text ? S.M. Zyryanov, D.V. Lopaev, 2007, published in Fizika Plazmy, 2007, Vol. 33, No. 6, pp. 563–574.     

The influence of phosphate concentration on the kinetics of uptake by maize roots

In an experiment with native maize roots depending on different phosphorus concentration in the external solution (0.001 … 50 mM P), the multiphasic character of the kinetics of phosphate uptake has been stated. The single phases are characterized by the different values of K_m and V_max. In the wide range of concentrations the isotherm of the phosphate uptake has five evident phases. The character of kinetics for the uptake of phosphate is analogical to the kinetics of the enzymatic reactions described by the Michaelis-Menten equation. On the other hand the linear dependence for the inactivated root was determined,i.e. the uptake of phosphate versus different phosphorus concentration in the external solution. The graphic representation of the logarithmic values for the phosphorus taken up versus the different phosphorus concentration in the external solution gives the biphasic course including concentration less than 1.0 mM P and more than 1.0 mM P. Within the framework of the concentration range the following values of V_max, K_m and ϕ_in were calculated under the conditions if the concentration of phosphorus is less than 1.0mMP: V_max = 1.705 μmol P × g^-1h^-1, K_m = 0.057 mM P and ϕ_in = 0.83,i.e. if the concentration of phosphorus is more than 1.0mM P: V_max = 40 μmol P × g^-1 h^-1, K_m = 16.66 mM and ϕ_in = 20. According to these results, the phosphate concentration in the external solution influences the activity of the transport mechanisms concerning their conformative changes which discretely change their working regime of membrane transport. This is also demonstrated in the change of values V_max, K_m and ϕ_in.     

Mechanism of action of aflatoxin B1

The inhibitory effects of aflatoxin B₁ were found to be related to the gram character in procaryotes, used in this study. Ethylene diamine tetra chloroacetic acid (0.05% w/v) or Tween-80 (0.05 % v/v) addition accentuated the aflatoxin B₁ growth inhibition inSalmonella typhi andEscherichia coli at different pH values. The inhibition of lipase production was only 5–20 % inPseudomonas fluorescence ca. 25–48% inStaphylococcus aureus andBacillus cereus at different aflatoxin B₁ concentrations (4–16μg/ml).However, inhibition of α-amylase induction was complete in1Bacillus megaterium whereas the inhibition was partial inPseudomonas fluorescence (27–40%) at 32μg aflatoxin B₁ concentration. An increase in leakage of cell contents and decreased inulin uptake were observed in toxin incubated sheep red blood cell suspension (1 %) with increased aflatoxin B₁ concentration     

Reduced fouling and enhanced microbial inactivation during online sterilization of cheese whey using UV coil reactors in series

The effectiveness of coil UV reactor series for the online sterilization of cheese whey was compared to those of the single conventional and coil reactors at various flow rates (5–70 mL/min). The residence time varied from 168 to 12 min and from 48 to 24 min for the single and the series reactors, respectively. Hundred percent destruction efficiency could not be achieved in the single reactors whereas in the coil reactor series the destruction efficiency reached 100% at the flow rates of 35 and 40 mL/min. The rate of microbial destruction was described by polynomial equation for the single coil reactor and by exponential equations for the single conventional reactor and the coil reactor series. The temperature of the effluent decreased with the increase in flow rate in all the reactors. The maximum effluent temperatures in the single conventional reactor, single coil reactor and coil reactor series were 45.8, 46.1, and 36.4 °C (Δt = 20.8, 21.1, 11.4 °C), respectively. The flow in all the reactors was laminar (R _e = 1.39–20.10) and the Dean number was in the range of 1.09–15.41 in the coil reactors. Visual observation revealed less fouling on the UV lamps of coil reactors than on that of the conventional reactor due to the impact of Dean flow. The total operating time during which 100% destruction efficiency is achieved prior to the advent of fouling was 240 min in the coil reactor series compared to only 45 min in the conventional reactor.     

Quantitative trait loci controlling water use efficiency and related traits in Quercus robur L.

Genetic variation for intrinsic water use efficiency (W _i) and related traits was estimated in a full-sib family of Quercus robur L. over 3 years. The genetic linkage map available for this F1 family was used to locate quantitative trait loci (QTL) for W _i, as estimated by leaf carbon stable isotope composition (δ ¹³C) or the ratio of net CO₂ assimilation rate (A) to stomatal conductance to water vapour (g _w) and related leaf traits. Gas exchange measurements were used to standardize estimates of A and g _w and to model the sensitivity of g _w to leaf-to-air vapour pressure deficit (sg^VPD). δ ¹³C varied by more than 3‰ among the siblings, which is equivalent to 40% variation of W _i. Most of the studied traits exhibited high clonal mean repeatabilities (>50%; proportion of clonal mean variability in global variance). Repeatabilities for δ ¹³C, leaf mass per area (LMA) and leaf nitrogen content were higher than 70%. For δ ¹³C, ten QTLs were detected, one of which was detected repeatedly for all 3 years and consistently explained more than 20% of measured variance. Four genomic regions were found in which co-localizing traits linked variation in W _i to variations in leaf chlorophyll and nitrogen content, LMA and sg^VPD. A positive correlation using clonal means between δ ¹³C and A/g _w, as well as a co-localisation of QTL detected for both traits, can be seen as validation of the theoretical model linking the genetic architecture of these two traits.     

Utilization of flue gas for cultivation of microalgae <Emphasis Type="Italic">Chlorella</Emphasis> sp.) in an outdoor open thin-layer photobioreactor

Flue gas generated by combustion of natural gas in a boiler was used for outdoor cultivation of Chlorella sp. in a 55 m² culture area photobioreactor. A 6 mm thick layer of algal suspension continuously running down the inclined lanes of the bioreactor at 50 cm s⁻¹ was exposed to sunlight. Flue gas containing 6–8% by volume of CO₂ substituted for more costly pure CO₂ as a source of carbon for autotrophic growth of algae. The degree of CO₂ mitigation (flue gas decarbonization) in the algal suspension was 10–50% and decreased with increasing flue gas injection rate into the culture. A dissolved CO₂ partial pressure (pCO₂) higher than 0.1 kPa was maintained in the suspension at the end of the 50 m long culture area in order to prevent limitation of algal growth by CO₂. NO_X and CO gases (up to 45 mg m⁻³ NO_X and 3 mg m⁻³ CO in flue gas) had no negative influence on the growth of the alga. On summer days the following daily net productivities of algae [g (dry weight) m⁻²] were attained in comparative parallel cultures: flue gas = 19.4–22.8; pure CO₂ = 19.1–22.6. Net utilization (η) of the photosynthetically active radiant (PAR) energy was: flue gas = 5.58–6.94%; pure CO₂ = 5.49–6.88%. The mass balance of CO₂ obtained for the flue gas stream and for the algal suspension was included in a mathematical model, which permitted the calculation of optimum flue gas injection rate into the photobioreactor, dependent on the time course of irradiance and culture temperature. It was estimated that about 50% of flue gas decarbonization can be attained in the photobioreactor and 4.4 kg of CO₂ is needed for production of 1 kg (dry weight) algal biomass. A scheme of a combined process of farm unit size is proposed; this includes anaerobic digestion of organic agricultural wastes, production and combustion of biogas, and utilization of flue gas for production of microalgal biomass, which could be used in animal feeds. A preliminary quantitative assessment of the microalgae production is presented.     

Rheological Behavior of Food Emulsions Mixed with Saliva: Effect of Oil Content, Salivary Protein Content, and Saliva Type

In this paper, we studied the effect of saliva on the rheological properties of β-lactoglobulin- and lysozyme-stabilized emulsions, prepared at pH = 6.7 in relation to variation of emulsions- and saliva-related parameters. The effect of oil–volume fraction (2.5% w/w to 10% w/w), salivary protein concentration (0.1 to 0.8 mg ml⁻¹), and the use of both stimulated and unstimulated saliva was investigated. Viscosity and storage modulus were measured before (η _emul and G′_emul, respectively) and after addition of saliva (η _mix and G′_mix). To better estimate the changes due to saliva-induced flocculation of the emulsions, the ratios η _mix/η _emul, G′_mix/G′_emul were calculated. In addition, tan δ (=the ratio of the loss and storage moduli) was investigated to evaluate the viscoelastic behavior of the emulsion/saliva mixtures. Increasing the oil–volume fraction and salivary protein concentration resulted in an increase in η _mix/η _emul and G′_mix/G′_emul, while a decrease in tan δ of the emulsion/saliva mixtures is occurring. When compared with unstimulated saliva, mixing β-lactoglobulin-stabilized emulsions with stimulated saliva led to a reduction in η _mix/η _emul and G′_mix/G′_emul, and an augment of tan δ at all measured deformations. In case of lysozyme-stabilized emulsions, the use of stimulated saliva increased G′_mix/G′_emul for γ < 3 when compared to unstimulated saliva. The effect of stimulated saliva on the η _mix/η _emul and tan δ in this mixture is similar to that of unstimulated saliva. These results indicate that the influence of stimulated saliva on the rheological parameters of emulsion/saliva mixtures largely depends on the type of emulsions. To conclude, our findings demonstrate that the rheological behavior of emulsions upon mixing with saliva is greatly affected by both saliva and emulsion properties.     

Effect of NaCl on kinetics ofd-glucosamine uptake in yeasts differing in halotolerance

The initial rate ofd-glucosamine uptake by the non-halotolerant yeastSaccharomyces cerevisiae was approximately halved as the apparent half saturation constant (K_m) and the apparent maximum velocity (V_max) changed from 6.6mm to 16.4mm and from 22 μmol · g⁻¹ · min⁻¹ to 16 μmol · g⁻¹ · min⁻¹, respectively, when the salinity in the medium was increased from zerom to 0.68m NaCl. Corresponding changes in a high affinity transport system in the halotolerant yeastDebaryomyces hansenii were from 1.1mm to 4.6mm and from 3.1 μmol · g⁻¹ · min⁻¹ to 4.5 μmol · g⁻¹ · min⁻¹, implying a practically unchanged transport capacity. In 2.7m NaCl, K_m and V_max in this system were 24.5mm and 1.1 μmol · g⁻¹ · min⁻¹, respectively, representing a marked decrease in transport capability. Nevertheless, the degree of affinity in this extreme salinity must still be regarded as noteworthy. In addition to the high affinity transport system inD. hansenii, a low affinity system, presumably without relevance ind-glucosamine transport, was observed.     

Hyaluronic acid depolymerization by ascorbate-redox effects on solid state cultivation of <Emphasis Type="Italic">Streptococcus zooepidemicus</Emphasis> in cashew apple fruit bagasse

The cashew fruit (Anacardium occidentale L.) has been used as a promising agricultural resource for the production of low-molecular weight (M_W) hyaluronic acid (HA) (10⁴–10⁵ Da). The cashew juice is a rich source of vitamin C containing, 1.2–2.0 g L⁻¹. This work explores the effects of the initial concentration of the ascorbate on the solid fermentation of the juice-moisturized bagasse from the cashew apple fruit. The results show that the M_W reduction of HA is proportional to the initial ascorbate concentration. The presence of ascorbate did not influence the Streptococcus zooepidemicus metabolism. However, the HA productivity was increased from 0.18 to 0.28 mg g⁻¹ h⁻¹ when the ascorbate concentration ranged from 1.7 to 10 mg mL⁻¹. These findings contribute to the controlled production of HA in a low M_W range, which is important in cell signalization, angiogenesis and nanoparticles production.     

Transpiration of spring barley under nitrogen and phosphorus deficiency during leaf wilting

In an open gas exchange system with a thermocouple psychrometer the transpiration rate of the first leaf in 8-day plants of spring barley was measured in dependence on the water saturation deficit (ΔW _sat). The plants were cultivated in Richter’s nutrient solution, either complete, or deficient in nitrogen or phosphorus. The cuticular transpiration (as measured in the dark) was unaffected by N and P deficiency. The N deficiency reduced the transpiration rate by increasing stomatal resistance since full water saturation of the leaf (67% rate of the control variant) up to stomatal closing at Δ W_sat = 14%. The P deficiency does not affect the transpiration rate at initial phases of wilting, but the stomata close only at a higher Δ W_sat (25%) than those in the control.     

Genotypic variation for drought tolerance in cotton (Gossypium hirsutum L.): Leaf gas exchange and productivity

Although water-limited environments are detrimental to cotton growth and productivity worldwide, identification of cotton (Gossypium hirsutum L.) genotypes that are less sensitive to drought may improve productivity in drought prone areas. The objective of the study was to assess genotypic variation for drought tolerance in cotton varieties using physiological attributes as selection criteria, and to determine the relationship of physiological attributes with productivity traits. The association of target physiological traits for drought tolerance (photosynthetic rate (P_n), stomatal conductance (g_s), and transpiration rate (E)) with productivity traits under well-watered (W₁) and water-limited (W₂) regimes was analyzed using 32 public cotton cultivars/bred lines in two field experiments conducted during the normal cotton growing seasons 2003 and 2004. Seed cotton yield (SCY) and biological yield (BY) were markedly affected under W₂ regime in all cultivars except the outstanding performance of CIM-1100 and RH-510 proving their superiority to other cultivars in drought tolerance. Conversely, FH-901, FH-634, and FH-2000 were high yielding under W₁ regime; however, exhibited a sharp decline in yield under W₂ regime. A positive correlation between SCY and BY under water stress (r=0.44 in 2003; r=0.69 in 2004) indicates that BY is also a primary determinant of SCY under water stress and genetic improvement of BY under water-limited environment may also improve SCY. P_n, g_s, and E were significantly reduced by water stress. Substantial genotypic variation for gas exchange attributes existed among the cotton cultivars. A positive association (P<0.01) was observed between g_s and E under both regimes in both years indicating the prevalence of stomatal control of transpiration. The positive association (P<0.01) between P_n and g_s in both years in W₂ regime indicates also a major role of stomatal effects in regulating leaf photosynthesis under water-limited conditions. P_n was significantly correlated with SCY (P<0.01) and BY (P<0.05 in 2003; P<0.01 in 2004) in W₂ regime; however, the level of these associations was not significant in W₁ regime. These findings demonstrate that association of P_n with productivity is effective under water-limited environment and may be useful as a selection criterion in breeding programs with the objective of improving drought tolerance and SCY under water-limited environments. Moreover, association between SCY and BY under water stress suggests that genetic improvement of BY under water stress may also improve SCY.     

Improvement of the anaerobic treatment of potato processing wastewater in a UASB reactor by co-digestion with glycerol

The effect of three different types of glycerol on the performance of up-flow anaerobic sludge blanket (UASB) reactors treating potato processing wastewater was investigated. High COD removal efficiencies were obtained in both control and supplemented UASB reactors (around 85%). By adding 2 ml glycerol product per liter of raw wastewater, the biogas production could be increased by 0.74 l biogas ml⁻¹ glycerol product, which leads to energy values in the range of 810–1270 kWh_electric per m³ product. Moreover, a better in-reactor biomass yield was observed for the supplemented UASB reactor (0.012 g VSS g⁻¹ COD_removed) compared to the UASB control (0.002 g VSS g⁻¹ COD_removed), which suggests a positive effect of glycerol on the sludge blanket growth.     

Effect of oral creatine ingestion on parameters of the work rate-time relationship and time to exhaustion in high-intensity cycling

The relationship between work rate (W˙) and time to exhaustion (t) during intense exercise is commonly described by either a hyperbolic function (NLin), t=W ^′/(W˙−W˙ _cp), or by its linear equivalent (LinW) W _lim =W ^′+W˙ _cp(t). The parameter W˙<INF _</INF>cp (critical power) has been described as an inherent characteristic of the aerobic energy system, while W ′ has been shown to be a ralid estimate of anaerobic work capacity. Recent studies have demonstrated that oral supplementation of creatine monohydrate (CrH₂O) increases total muscle creatine stores, and have linked these increases to improved performances in intense intermittent exercise. This study was conducted to determine the effect of CrH₂O supplementation on estimates of W ′ and W˙<INF _</INF>cp derived from the NLin and LinW equations, and to determine the effect of CrH₂O on t in exhaustive constant power exercise of different intensities. Fifteen active but untrained university students completed three phases of testing on a cycle ergometer: (1) familiarization, three learning trials, (2) baseline determination of W ′ and W˙<INF _</INF>cp, four bouts performed at a W˙ selected to elicit fatigue in 90–600 s, and (3) experimental determination of W ′ and W˙ _cp, four bouts performed at the same W˙ as baseline, but performed after 5 days of ingesting either a placebo (4 × 6 g of glucose/day) or CrH₂O (4 × 5 g of CrH₂O and 1 g glucose/day). Testing was administered in a double-blind manner. Analyses of covariance revealed a significant effect for CrH₂O on both estimates of W ′ (NLin, P=0.04; LinW, P<0.01), but not on estimates of W˙ _cp (NLin, P=0.37; LinW; P=0.30). Within groups, t was significantly different for only CrH₂O at the two highest W˙s (P=0.04). It is concluded that oral ingestion of CrH₂O increases estimates of W ′ due to an improved t at the shorter, more intense exercise bouts. Accepted: 1 September 1997     

Transpiration efficiency of three Mediterranean annual pasture species and wheat

Attempts to improve water use efficiency in regions with Mediterranean climates generally focus on increasing plant transpiration relative to evaporation from the soil and increasing transpiration efficiency. Our aim was to determine if transpiration efficiency differs among key species occurring in annual pastures in southern Australia. Two glasshouse experiments were conducted with three key pasture species, subterranean clover (Trifolium subterraneum L.), capeweed [Arctotheca calendula (L.) Levyns] and annual ryegrass (Lolium rigidum Gaudin), and wheat (Triticum aestivum L.). Transpiration efficiency was assessed at the levels of␣whole-plant biomass and water use (W), leaf gas exchange measurements of the ratio of CO₂ assimilation to leaf conductance to water vapour (A/g), and carbon isotope discrimination (Δ) in leaf tissue. In addition, Δ was measured on shoots of the three pasture species growing together in the field. In the glasshouse studies, annual ryegrass had a consistently higher transpiration efficiency than subterranean clover or capeweed by all methods of measurement. Subterranean clover and capeweed had similar transpiration efficiencies by all three methods of measurement. Wheat had W values similar to ryegrass but A/g and Δ values similar to subterranean clover or capeweed. The high W of annual ryegrass seems to be related to a conservative leaf gas exchange behaviour, with lower assimilation and conductance but higher A/g than for the other species. In contrast to the glasshouse results, the three pasture species had similar Δ values when growing together in mixed-species swards in the field. Reasons for these differing responses between glasshouse and field-grown plants are discussed in terms of the implications for improving the transpiration efficiency of mixed-species annual pasture communities in the field. Received: 6 March 1997 / Accepted: 23 December 1997     

Highly Tough,Li‐Metal Compatible Organic–Inorganic Double‐Network Solvate Ionogel

Ionogels are considered promising electrolytes for safe lithium‐ion batteries (LIBs) because of their low flammability, good thermal stability, and wide electrochemical stability window. Conventional ionic liquid‐based ionogels, however, face two main challenges; poor mechanical property and low Li‐ion transfer number. In this work, a novel solvate ionogel electrolyte (SIGE) based on an organic–inorganic double network (DN) is designed and fabricated through nonhydrolytic sol–gel reaction and in situ polymerization processes. The unprecedented SIGE possesses high toughness (bearing the deformation under the pressure of 80 MPa without damage), high Li‐ion transfer number of 0.43, and excellent Li‐metal compatibility. As expected, the LiFePO₄/Li cell using the newly developed SIGE delivers a high capacity retention of 95.2% over 500 cycles, and the average Coulombic efficiency is as high as 99.8%. Moreover, the Ni‐rich LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811)/Li cell based on the modified SIGE achieves a high Coulombic efficiency of 99.4%, which outperforms previous solid/quasi‐solid‐state NCM811‐based LIBs. Interestingly, the SIGE‐based pouch cells are workable under extreme conditions (e.g., severely deforming or clipping into segments). In terms of those unusual features, the as‐obtained SIGE holds great promise for next‐generation flexible and safe energy‐storage devices.     

Photosynthesis Inhibition During Gas Exchange Oscillations in ABA-Treated Helianthus annuus: Relative Role of Stomatal Patchiness and Leaf Carboxylation Capacity

Environmental factors that induce spatial heterogeneity of stomatal conductance, g _s, called stomatal patchiness, also reduce the photochemical capacity of CO₂ fixation, yet current methods cannot distinguish between the relative effect of stomatal patchiness and biochemical limitations on photosynthetic capacity. We evaluate effects of stomatal patchiness and the biochemical capacity of CO₂ fixation on the sensitivity of net photosynthetic rate (P _N) to stomatal conductance (g _s), θ (θ = δP _N/g _s). A qualitative model shows that stomatal patchiness increases the sensitivity θ while reduced biochemical capacity of CO₂ fixation lowers θ. We used this feature to distinguish between stomatal patchiness and mesophyll impairments in the photochemistry of CO₂ fixation. We compared gas exchange of sunflower (Helianthus annuus L.) plants grown in a growth chamber and fed abscisic acid, ABA (10⁻⁵ M), for 10 d with control plants (-ABA). P _N and g _s oscillated more frequently in ABA-treated than in control plants when the leaves were placed into the leaf chamber and exposed to a dry atmosphere. When compared with the initial CO₂ response measured at the beginning of the treatment (day zero), both ABA and control leaves showed reduced P _N at particular sub-stomatal CO₂ concentration (c _i) during the oscillations. A lower reduction of P _N at particular g _s indicated overestimation of c _i due to stomatal patchiness and/or omitted cuticular conductance, g _c. The initial period of damp oscillation was characterised by inhibition of chloroplast processes while stomatal patchiness prevailed at the steady state of gas exchange. The sensitivity θ remained at the original pre-treatment values at high g _s in both ABA and control plants. At low g _s, θ decreased in ABA-treated plants indicating an ABA-induced impairment of chloroplast processes. In control plants, g _c neglected in the calculation of g _s was the likely reason for apparent depression of photosynthesis at low g _s. This revised version was published online in August 2006 with corrections to the Cover Date.     

Relationships between dynamics of nitrogen uptake and dry matter accumulation in maize crops. Determination of critical N concentration

The concept of critical nitrogen concentration(%N _c) has been proposed as the minimum%N in shoots required to produce the maximum aerial biomassat a given time. Several authors have shown that%N _c declines as a function of aerial biomassaccumulation (W) and the %N _c –W relationship has been proposed as a diagnostic tool of N statusin different crops, excluding maize. From data obtained in five nitrogenfertilisation experiments in irrigated maize crops, 26 critical data-pointswere selected with a precise statistical procedure. An allometric relationwas fitted and a critical %N−W relationshipmodel is proposed in maize as: If W < 1 t ha^-1%N _c = 3.40 If 1 t ha^-1≤ W ≤ 22 t ha^-1%N _c = 3.40(W)^−0.37 The model is applicable to maize crop development between emergenceand silking + 25 days. The model was tested and validated with dataobtained in a network of 17 N fertilisation experiments conducted inFrance under contrasting pedoclimatic conditions. In only nineout of 280 data-points (3.2%), the plant N status was mispredictedwhen ±5% error around %N _c wasallowed. A critical N uptake model (Nu_c, kg Nha^-1) is proposed as Nu_c = 34 (W)^0.63 A comparison between Nu_c and N uptake observedin N treatments giving the maximal grain yields has shown that maizecrops assimilate at least 30 kg N ha^-1 in a storage N poolat the silking stage. The significance of the critical%N−W and Nu−W relationships is discussed in relation to theoretical models proposed inwhole plant ecophysiology. Different relationships calculated betweenleaf area index and aerial biomass accumulation, and between N uptakeand leaf area were consistent with previous results for other crops.This strengthens the interest of the critical%N−W relationship for use as diagnostictool of nitrogen status in maize crops. This revised version was published online in June 2006 with corrections to the Cover Date.