Zn Density Research Articles

Adsorption of Zn(II) on the kaolinite(001) surfaces in aqueous environment: A combined DFT and molecular dynamics study

Adsorption of Zn(II) on two types of neutral (001) surfaces of kaolinite, tetrahedral Si(t) and octahedral Al(o), was studied by means of DFT calculations and classical molecular dynamics simulations. The position and structure for both outer-sphere and mono-/bi-dentate inner-sphere complexes of Zn(II) in aqueous environment were examined, with binding energy and radial distribution function calculated. Outer-sphere complex on the Si(t) surface, monodentate inner-sphere complex of “Ou” (surface oxygen with “upright” hydrogen) site and bidentate complex of “Ou-Ou” site of neighboring Al centers on the Al(o) surface are considered to be the dominant adsorption species. The outer-sphere complex is found six-coordinated with distorted octahedral geometry, while both the inner-sphere complexes exhibit the tetrahedral structure with coordination number of four. Hydrogen bonding interactions between oxygen or hydrogen of the kaolinite(001) surfaces and the aqua ligands of Zn(II) act as the key role for the structure and stability of adsorption complexes. Upon the Mulliken population analysis and partial density of states, both Zn(II) and surface oxygen accept electrons from aqua oxygens, and coupling of O 2p with the sp3d2 or sp3 hybridization states of Zn(II) is the primary bonding nature of Zn(II) with oxygen in outer- and inner-sphere complexes, respectively.

A Zinc Nitrate–Calcium Nitrate–Water System: The Solubility of Solids and the Density of Liquids in a Wide Range of Temperatures

The equilibrium phase diagram of the Zn(NO3)2–Ca(NO3)2–H2O system at 251.85, 262.35, and 288.15 K was studied by the isothermal solution saturation method and wet residue analysis. Densities of ternary Zn(NO3)2–Ca(NO3)2–H2O solutions were measured at 298.15–321.35 K. For some solutions, pH measurements were provided at 298.15 K.

Possible effect of threshing method on grain iron and zinc density estimation in pearl millet: a contribution to biofortification breeding

In crop biofortification research, threshing part is the primary place of contamination while dealing with grain mineral traits such as iron (Fe) and zinc (Zn) density, thus type of threshing operation is one of the important and effective factors for efficient grain mineral traits determination. This study is aimed at the effects of threshing methods namely power-operated single-head thresher and manual-hand threshing on Fe and Zn density estimation. In this context, 50 pearl millet progenies each from two broad-based populations (AIMP 92901 and ICMR 312) were evaluated in field condition and tested for machine and hand threshing. Grain samples were analyzed for Fe and Zn density using Inductively Coupled Plasma Optical-Emission Spectrometry (ICP-OES) method. The analysis of variance showed the significant difference among population progenies for these micronutrients by recording two-fold variations for Fe (40-91 mg kg-1) and Zn (32-74 mg kg-1) density. Threshing method had significant effect, however, estimated Fe and Zn values from both the methods were highly comparable, further non-significant t-test and linear correlations-coefficients showed machine-threshed samples results were highly positively significantly correlated with hand-threshed samples values for both micronutrients (r=0.88 to 0.93; p<0.01 for Fe and r= 0.92 to 0.95; p<0.01 for Zn) in two populations. This study indicating the high levels of consistency on ranking of test entries and threshing method has no effect on grain Fe and Zn estimation. Therefore, single-head thresher will be a reliable and faster method for large-number of breeding materials threshing and its grain micronutrient determination in pearl millet biofortification.

Energy-Dispersive X-ray Fluorescence Spectrometry for Cost-Effective and Rapid Screening of Pearl Millet Germplasm and Breeding Lines for Grain Iron and Zinc Density

ABSTRACTComparison of energy-dispersive X-ray fluorescence (XRF) and inductively coupled plasma-optical emission spectroscopy (ICP) for iron (Fe) and zinc (Zn) densities in pearl millet grain samples from 11 trials showed significant differences between these two methods for both micronutrients. XRF values were more often higher than the ICP values for both micronutrients, but the differences were significant in only 15–38% genotypes for Fe and in 7–25% genotypes for Zn across the trials. In 82% genotypes the differences between these two methods were ≤6 mg kg−1 for Fe; and in 88% genotypes, the differences were ≤4 mg kg−1for Zn. There were highly significant and high positive correlations between ICP and XRF for both micronutrients. Selection of genotypes above the XRF trial mean for Fe/Zn included at least 30% top-ranking genotypes based on ICP. Therefore, XRF can be used for cost-effective and rapid screening of a large number of grain samples in pearl millet biofortification programs.

Strategy for enhancing the solar-driven water splitting performance of TiO2 nanorod arrays with thin Zn(O,S) passivated layer by atomic layer deposition

An array of one dimensional (1D) TiO2 nanorods (TONRs) has been regarded as an attractive candidate for electrochemical energy conversion and as storage device due to its large surface area, effiective light scattering, and undisturbed charge transport pathway. However, the high defect/trap densities on surface of the nanostructured morphology and architecture may generally hinder the performance enhancement by providing electron-hole recombination sites. Hence, the surface passivation of nanoarchitectures based photoelectrodes has recently received much attention as an effective strategy to enhance the charge-separation and charge-transfer processes in photoelectrochemical (PEC) water splitting devices. In particular, a coating layer with narrowing band gap materials can promote enhanced light harvesting in the UV–vis region as well as surface passivation, directly supplying a driving force for charge separation and charge transfer due to band alignment. In this paper, the surface of TONRs were passivated by 10 and 30nm thick Zn(O,S) layers with a relatively narrow band gap using an atomic layer deposition technique to modulate the thickness exactly. The 10nm Zn(O,S)/TONR array exhibits a significantly enhanced photocurrent density (Jsc) of 5.94mA/cm2 at 1.23eV vs NHE and an incident photon-to-electron conversion efficiency (IPCE) of 49% at 374nm compared with that of TONR arrays (Jsc of 1.99mA/cm2 at 1.23eV vs NHE and an IPCE of 20% at 380nm). However, the PEC performance is worse in the 30nm Zn(O,S)/TONR arrays, showing a Jsc of 3.09mA/cm2 at 1.23eV vs NHE and an IPCE of 29% at 374nm. To clearly demonstrate these PEC behaviors, the TONR and Zn(O,S)/TONR arrays were characterized by electrochemical impedance spectroscopy (EIS), open circuit voltage decay (OCV) measurement, and X-ray photoelectron spectroscopy (XPS). The above mentioned characterizations indicate that the enhanced PEC performance of the 10nm Zn(O,S)/TONR array resulted from the (i) increased light harvesting in the UV–vis region, (ii) lower charge transfer resistance and (iii) high value of valence band offset (VBO, −1.44eV) and conduction band offset (CBO, −1.2eV) than those of the TONR. However, the deterioration of Jsc in the 30nm Zn(O,S)/TONR array is attributed to the negative value of VBO (-0.13eV) and positive value of CBO (+0.27eV), as well as the higher charge transfer resistance to the electrolyte than that of the TONR arrays, despite of the improved light absorption in the visible region. The photocurrent densities of 10nm Zn(O,S)/TONR and 30nm Zn(O,S)/TONR photocathodes decay to 4.718mA/cm2 (5.90mA/cm2 at 0min) and 2.212mA/cm2 (3.03mA/cm2 at 0min) after 90min, respectively, they retain of about∼80% and 70% of its original values. These experimental results and discussions not only provide the physical insights into the surface passivation effect and band alignment but also can open a promising route to design the thin passivation layer having the narrowing band gap energy (1.0eV∼2.5eV) on the 1D TiO2 nanostructure for further enhanced performance and realization of a TiO2 based PEC system.

Absolute densities of Cu, Zn, Sn, and S atoms in magnetron sputtering plasmas employing a Cu2ZnSnS4 target

Absolute densities of Cu, Zn, Sn, and S atoms in magnetron sputtering plasmas were measured by ultraviolet absorption spectroscopy and vacuum ultraviolet absorption spectroscopy. A stoichiometric Cu2ZnSnS4 (CZTS) target was used in this work. It was found that, at various Ar pressures, the S density ranged between (2–8) × 1010 cm−3, the Cu and Sn densities ranged between (0.6–3) × 1010 cm−3, and the Zn density ranged between (2–3) × 109 cm−3. The effective depositing flux, which was evaluated from the absolute densities and the sticking probabilities, was comparable with that evaluated from the deposition rate of the CZTS film. However, the composition ratio of Cu, Zn, Sn, and S in the gas phase deviated from the ideal stoichiometry of CZTS. We discussed the possible mechanisms for the difference among the element compositions of the target, the deposited film, and the gas-phase densities.

Grain iron and zinc densities in released and commercial cultivars of pearl millet (Pennisetum glaucum)

Crop biofortification is a cost-effective and sustainable agricultural strategy to reduce micronutrient malnutrition arising from iron (Fe) and zinc (Zn) deficiencies. A large number of hybrids and open-pollinated varieties (OPVs) of pearl millet [Pennisetum glaucum (L.) R. Br.] have been released and/or commercialized in India. Eighteen OPVs and 15 high-Fe candidate hybrids were evaluated in multi-location trials for Fe and Zn density to identify those with high density of these micronutrients. The Fe density in OPVs varied from 42 mg/kg to 67 mg/kg, and Zn density from 37 mg/kg to 52 mg/kg with ICTP 8203 having the highest Fe density (67 mg/kg) followed by ICMV 221 (61 mg/kg) and AIMP 92901 (56 mg/kg). While ICTP 8203 had also the highest level of Zn density (52 mg/kg), ICMV 221 and AIMP 92901 had 45-46 mg/kg Zn density. The Fe density in hybrids varied from 46 mg/kg to 56 mg/kg and Zn density from 37 mg/kg to 44 mg/kg. Four hybrids, viz. Ajeet 38, Proagro XL 51, PAC 903 and 86M86 had the highest Fe density of 55-56 mg/kg and 39-41 mg/kg Zn density. The six commercial cultivars (2 OPVs and 4 hybrids) identified in this study with high Fe and Zn densities can be undertaken for expanded cultivation in their recommended ecologies to specifically address the Fe and Zn deficiencies in India. This study also enabled to re-define base line for Fe density at 42 mg/kg for hybrids, the most dominant cultivar type grown in India.

Zinc accumulation in lettuce cultivars grown with organic or chemical based nutritional regimes

ABSTRACTThis study determined the potential to increase Zn density of lettuce (Lactuca sativa L.) through cultivar selection and nutrient management. Organic fertilizer and Hoagland and Arnon no.1 solution factored with three zinc (Zn) levels provided as zinc sulfate (ZnSO4) were the fertilizer regimes in a greenhouse experiment. Modern cultivars had a 32% higher fresh head weight than heritage cultivars, but each accumulated the same Zn concentration (65 mg kg−1 dry wt). Butterhead phenotypes had a 38% lower yield than loose-leaf and had the highest Zn concentration (78 mg kg−1 dry wt) followed by romaine (66 mg kg−1 dry wt) and loose-leaf (53 mg kg−1 dry wt). Concentration of Zn did not differ between fertility regimes, being about 66 mg kg−1 dry wt with each regime. Differences in Zn concentrations were significant among individual cultivars with ranges from 42 mg g−1 dry wt to 91 mg kg−1 dry wt. ‘Tom Thumb’, ‘Adriana’, ‘Claremont’, and ‘Focea’ were the top in cultivar ranking, with mean Zn concentration of 63 mg kg−1 dry wt. The results signify that selection of cultivars may be utilized to increase Zn accumulation in lettuce but that nutritional regimes had little effect on accumulation.

Tester Effect on Combining Ability and Its Relationship with Line Performance per se for Grain Iron and Zinc Densities in Pearl Millet

Development of inbred lines with high general combining ability (GCA) is an important aspect of hybrid breeding research. Although broad‐based open‐pollinated populations (varieties and composites) are widely used to assess GCA of inbred lines and population progenies, identification of the most effective testers has remained a continuing challenge. Two broad‐based and diverse populations of pearl millet [Pennisetum glaucum (L.) R. Br.] were crossed with 14 diverse inbred lines in each of two experiments to produce 56 topcross hybrids, which were evaluated along with their parental lines for grain Fe and Zn densities. Results showed that there was highly significant and moderately high positive correlation between the topcross hybrid performance per se (a measure of GCA) produced with the two testers, both for Fe and Zn densities in both experiments. However, the correlation between performance per se of lines and their topcross hybrids averaged over both testers (giving more reliable estimates of GCA than individual testers) was even higher for both micronutrients and in both experiments. Thus, while each tester was effective in identifying 30 to 35% of the top‐ranking high general combiners as reflected in topcross hybrid performance, line performance per se was even more effective in identifying these top‐ranking combiners for both micronutrients in both experiments, indicating that based on performance per se lines can be selected for high GCA of Fe and Zn densities in pearl millet.

Genetic architecture of open-pollinated varieties of pearl millet for grain iron and zinc densities

Genetic architecture of two commercial open-pollinated varieties of pearl millet (ICTP 8203 and ICMV 221) for grain iron and zinc densities was studied using 160 full-sib progenies each that were developed following North Carolina Design-1 and evaluated for two seasons. Results showed predominantly additive genetic variance and nonsignificant additive gene effect × environment interaction variance compared to large and significant dominance × environment interaction variance for both micronutrients in both populations. This translated into high narrow-sense heritability for Fe (65%) and Zn (86%) in ICTP 8203, and moderate heritability of 45% for both micronutrients in ICMV 221. In comparison, 1000-seed weight, generally assumed to be highly heritable, was predominantly under dominance gene control and had large dominance × environment interaction, giving the narrow-sense heritability estimates of 31% in ICTP 8203 and 13% in ICMV 221. These results, and highly significant and positive correlation observed between Fe and Zn densities, and non-significant correlations of these micronutrients with grain weight suggest that simultaneous selection for Fe and Zn densities in these populations can be effectively made without compromising the grain size.

Effect of dietary zinc oxide and phytase on the plasma metabolites and enzyme activities in aged broiler breeder hens

Background: It has been shown that zinc has an effect on physiological responses in animals and birds. On the other hand, dietary phytase in poultry results in increased availability of zinc. OBJECTIVES: This study was conducted to investigate the effects of zinc oxide (ZnO) and Escherichia coli-derived 6-phytase supplemented diets on the plasma metabolites and enzyme activities of broiler breeder hens from 60 to 72 weeks of age. METHODS: A total of 128 breeder hens were randomly assigned to eight dietary treatments, with four replicates of four hens each. Blood concentration of Zn, Ca, P, total protein, cholesterol, triglyceride (TG) and high density lipoprotein (HDL), and plasma activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) were measured. RESULTS: Results showed that supplementary ZnO increased plasma Zn, Ca, P, HDL, and total protein (p<0.01) concentrations, as well as enzyme activities of LDH, ALT and AST (p<0.01). Also, a ZnO-supplemented diet resulted in a decrease in plasma cholesterol and TG (p<0.01) levels. Adding phytase to the diet increased plasma (P) and HDL contents (p<0.01). The interactive effect of phytase × ZnO × period on the plasma levels of Zn, P, total protein, HDL, total cholesterol, and the enzymatic activity of LDH, ALT and ALP was significant. CONCLUSIONS: It is concluded that supplementary ZnO and phytase may improve metabolism and enzymatic activity of aged broiler breeder hens.

An effective strategy to improve grain zinc concentration of winter wheat, Aphids prevention and farmers’ income

Foliar zinc (Zn) application represents an effective way to improve grain Zn concentration of cereal crops. Spraying Zn together insecticides would be an important advantage for the growers to minimize costs. However, there is very little information about combined foliar application of Zn fertilizers together with insecticides. A field experiment was conducted to investigate how spraying Zn fertilizer in form of ZnSO4 together with commonly applied insecticides (e.g., Acetamiprid and Imidacloprid) affects the grain Zn concentration of wheat grown in the Northern China Plain. The main treatment included three levels: only insecticide applied (recorded as T1); foliar Zn fertilizer applied one day after insecticide application (recorded as T2); foliar Zn fertilizer applied together with insecticide (recorded as T3). The results showed that there was no antagonistic effect between insecticide and Zn when they were sprayed together. Compared with insecticide application only, foliar application of Zn fertilizer with insecticide increased grain yield by 3.7–4.9%, and grain Zn density by 48.2–61.6%. Grain yield and grain Zn concentration were not affected no matter Zn fertilizers were applied simultaneously with insecticide or one day after. The toxic effect of insecticide on insects was not affected when it was mixed with Zn fertilizer in the laboratory condition. Compared with application of Zn fertilizer and insecticide at different times, simultaneous combination can reduce the cost by 120 USDha−1 and increase farmers’ net income by 6.3%. Therefore the results show clearly that ZnSO4 can be mixed and sprayed together with insecticide without causing any adverse effect. This is a very useful and cost-effective approach for growers contributing both to improving grain yield and grain Zn concentration and controlling aphids as well.

Synthesis and characterization of carbon black/manganese oxide air cathodes for zinc–air batteries: Effects of the crystalline structure of manganese oxides

Manganese oxides (MnOx) in α-, β-, γ-, δ-MnO2 phases, Mn3O4, Mn2O3, and MnOOH are synthesized for systematically comparing their electrocatalytic activity of the oxygen reduction reaction (ORR) in the Zn–air battery application. The optimal MnOx/XC-72 mass ratio for the ORR is equal to 1 and the oxide crystalline structure effect on the ORR is compared. The order of composites with respect to decreasing the ORR activity is: α-MnO2/XC-72 > γ-MnO2/XC-72 > β-MnO2/XC-72 > δ-MnO2/XC-72 > Mn2O3/XC-72 > Mn3O4/XC-72 > MnOOH/XC-72. The textural properties of MnOx are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption/desorption isotherms with Brunauer–Emmett–Teller (BET) analysis, X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Electrochemical studies include linear sweep voltammetry (LSV), rotating ring-disk electrode (RRDE) voltammetry, and the full-cell discharge test. The discharge peak power density of Zn–air batteries varies from 61.5 mW cm−2 (α-MnO2/XC-72) to 47.1 mW cm−2 (Mn3O4/XC-72). The maximum peak power density is 102 mW cm−2 for the Zn–air battery with an air cathode containing α-MnO2/XC-72 under an oxygen atmosphere when the carbon paper is 10AA. The specific capacity of all full-cell tests is higher than 750 mAh g−1 at all discharge current densities.

Mechanism investigation and surface complexation modeling of zinc sorption on aluminum hydroxide in adsorption/coprecipitation processes

The sorption mechanism of dilute Zn [initial Zn(II) concentration up to 40mgdm−3] on aluminum hydroxide was investigated. Adsorption and coprecipitation at pH 7 were compared. The adsorption process gave a Langmuir-type isotherm and the zeta potential of Zn(II)-adsorbed aluminum hydroxide decreased linearly with increasing sorption density of Zn on aluminum hydroxide. The adsorption mechanism is therefore mainly surface complexation. In contrast, in the coprecipitation process, a Brunauer–Emmett–Teller like isotherm was obtained; the slope of the zeta potential versus Zn(II) sorption density decreased when the initial Zn/Al molar ratio was greater than 0.5. The X-ray diffraction pattern of Zn(II)-coprecipitated aluminum hydroxide changed from that of poorly crystalline gibbsite to a Zn–Al layered double-hydroxide (LDH) when the initial Zn/Al molar ratio was greater than 0.5, showing that surface complexation was the main sorption mechanism, but surface precipitation of Zn–Al LDH was also involved when the initial Zn/Al molar ratio in the coprecipitation process was greater than 0.5. A quantitative diffuse-layer model was constructed. The aluminum hydroxide exchange capacity was set at 0.61molmol-Al−1, based on the experimentally determined surface area, 340m2g−1. Surface complexation coefficients for H+, OH−, and Zn(II) adsorption on aluminum hydroxide were determined by fitting to the experimental adsorption results. The obtained parameters were in excellent agreement with those previously reported for a database of gibbsite adsorption equilibrium constants. The pH edge for Zn(II) removal by aluminum hydroxide was successfully reproduced by the constructed model.

Seed Set and Xenia Effects on Grain Iron and Zinc Density in Pearl Millet

ABSTRACTThree types of seed samples (selfed, sibbed and open pollinated) can be used for mineral analysis in pearl millet [Pennisetum glaucum (L.) R. Br.] and other cross‐pollinated crops. Cost effectiveness and reliability of mineral estimates in these types of seed samples have a direct bearing on breeding efficiency. Three sets of experiments using a diverse range of materials were conducted to examine the potential use of selfed and open pollinated (OP) seed samples for the analysis of grain Fe and Zn density in pearl millet. The results of this study showed that reduction in seed set under selfing, a genotype‐dependent typical trait of this crop, led to significant and large overestimates of Fe and Zn density, indicating that selfed seeds cannot be used for reliable estimation of grain Fe and Zn density. There was no significant difference between the sibbed and crossed seeds, indicating that there was no xenia effect. Differences among the sibbed and OP seeds for Fe, Zn, and Al density were small in magnitude and not always significant, indicating that dust contamination was not a significant factor determining Fe and Zn density. Since production of OP seed is most cost effective, it can be used for reliable estimation of Fe and Zn density when dealing with a large number of breeding lines, thereby enhancing the breeding efficiency for these micronutrients in pearl millet.

Dyshomeostasis of Serum Oxidant/Antioxidant Status and Copper, Zinc, and Selenium Levels in Elderly Physically Disabled Persons: an AHAP-Based Study.

The percentage of elderly persons is rapidly growing. Physical disability is one of the main age-related diseases which affect life quality. There are some studies that suggest the oxidative stress and trace elements are involved in physical disability in elderly persons, but the results are inconclusive. Therefore, the aim of this study was to investigate the status of aforementioned parameters in elderly physically disabled patients vs. healthy ones. According to the Katz questionnaire form, 44 subjects with physical disability and 66 age-gender-matched healthy subjects were selected from Amirkola Health and Aging Project (AHAP). The results indicated that patient group had lower serum Zn, Se, and total antioxidant levels than the control group (p < 0.001), whereas serum total oxidant level and Cu to Zn ratio (CZr) were higher in control group than in healthy one (p < 0.001). A positive correlation was found between Zn, Se, total antioxidant, and bone mineral density of femur (BMD.F) with activities of daily living (ADL) score (p < 0.01); meanwhile, a negative correlation between CZr and total oxidant with ADL score was observed (p < 0.01). Serum total oxidant level and CZr index had the highest area under the curve in receiver operating characteristic (ROC) analysis among the included parameters for discrimination of physically disabled patients than the normal ones. Decrease in serum Zn and Se levels, low BMD, and increase in CZr and oxidative stress were observed in physically disabled patients. It seems that CZr is more reliable parameter than the others to discriminate the physically disabled patients than the healthy persons.

Grain iron and zinc density in pearl millet: combining ability, heterosis and association with grain yield and grain size.

Genetics of micronutrients and their relationships with grain yield and other traits have a direct bearing on devising effective strategies for breeding biofortified crop cultivars. A line × tester study of 196 hybrids and their 28 parental lines of pearl millet (Pennisetum glaucum (L.) R.Br.) showed large genetic variability for Fe and Zn densities with predominantly additive gene action and no better-parent heterosis. Hybrids with high levels of Fe and Zn densities, involved both parental lines having significant positive general combining ability (GCA), and there were highly significant and high positive correlations between performance per se of parental lines and their GCAs. There was highly significant and high positive correlation between the Fe and Zn densities, both for performance per se and GCA. Fe and Zn densities had highly significant and negative, albeit weak, correlations with grain yield and highly significant and moderate positive correlation with grain weight in hybrids. These correlations, however, were non-significant in the parental lines. Thus, to breed hybrids with high Fe and Zn densities would require incorporating these micronutrients in both parental lines. Also, simultaneous selection for Fe and Zn densities based on performance per se would be highly effective in selecting for GCA. Breeding for high Fe and Zn densities with large grain size will be highly effective. However, combining high levels of these micronutrients with high grain yield would require growing larger breeding populations and progenies than breeding for grain yield alone, to make effective selection for desirable recombinants.Electronic supplementary materialThe online version of this article (doi:10.1186/2193-1801-3-763) contains supplementary material, which is available to authorized users.

Optical absorption spectroscopy of facing targets and conventional magnetron sputtering during process of Al-doped ZnO films

Facing targets sputtering (FTS) is a promising process for low-temperature TCO film deposition and for the significant reduction of damage in film structure by suppression of the direct impinging of high-energy particles due to confining plasma between two facing magnetic fields compared with conventional magnetron sputtering (CMS). In this study, FTS was compared with CMS by measuring Zn densities during the deposition process of Al-doped ZnO films with DC and 13.56MHz RF discharge at various process conditions. Optical absorption spectroscopy (OAS) was adopted for measuring Zn densities, for which a hollow cathode lamp was used as a source light of a 213.9nm line, which was selected to measure absorption coefficients and to calculate the ground state densities of Zn atoms. When RF power was applied, Zn densities were lower than in DC conditions in both CMS and FTS. Interestingly, in FTS, Zn densities were observed to be lower than in CMS regardless of the RF and DC powers, indicating an increase of plasma density associated with the high ionization rate and collision rate of FTS.

Iniadi pearl millet germplasm as a valuable genetic resource for high grain iron and zinc densities

Crop biofortification is increasingly being recognized as a cost-effective and sustainable approach to address the widespread micronutrient malnutrition arising from Fe and Zn deficiencies. Pearl millet as a cereal crop species has higher Fe density than all other major cereals. Earlier studies in pearl millet have shown that breeding lines, hybrid parents, improved populations and composites having high Fe and Zn densities were often based largely or entirely on iniadi pearl millet germplasm. In an attempt to identify additional sources of high Fe density in this group of germplasm, 297 accessions were screened using Perl's Prussian Blue staining, of which 191 accessions (118 from Togo, 62 from Ghana and 11 from Burkina Faso) were re-evaluated during the 2010 rainy and 2012 summer seasons using the inductively coupled plasma atomic emission spectroscopy method. On the basis of the mean performance over the two seasons (environments), large variability was observed for both Fe (51–121 mg/kg) and Zn (46–87 mg/kg) densities. There was a highly significant and positive correlation between the two micronutrients (r= 0.77, P&lt; 0.01). Of these re-evaluated accessions, 49% had higher Fe density than the high-Fe control commercial cultivar ICTP 8203 (81 mg/kg), and most of these accessions also had Zn density ≥ 61 mg/kg (59 mg/kg for ICTP 8203). A total of 27 accessions (20 from Togo and seven from Ghana) having a Fe density of 95–121 mg/kg (1 standard error of difference above that for ICTP 8203) and a Zn density of 59–87 mg/kg were selected as a valuable germplasm resource for genetic improvement of these two micronutrients in pearl millet.

Interface-Barrier-Induced J–V Distortion of CIGS Cells With Sputtered-Deposited Zn(S,O) Window Layers

Sputtered-deposited Zn(S,O) is an attractive alternative to CdS for the window layer of Cu(In,Ga)Se 2 (CIGS) thin-film solar cells due to its higher band gap, which allows greater blue-photon collection. However, distortions to current-voltage ( J-V) curves are observed in some cases. A straightforward photodiode model with a secondary barrier at the Zn(S,O)/CIGS interface is employed to explain the physical mechanisms of the experimental J-V distortions. The primary contributor to the secondary barrier is the conduction-band offset (CBO), whose magnitude is determined by the oxygen fraction in Zn(S,O) and by the carrier density of Zn(S,O); the latter may be increased with indium-doping. Comparison of experimental and simulated J-V characteristics with variation in oxygen fraction, window carrier density, and temperature, allows a reasonably compelling test of the secondary-barrier model for this system.