Copper Content Research Articles

Alleviation of cadmium toxicity by improving antioxidant defense mechanism and nutrient uptake in wheat (Triticum aestivum L.) through foliar application of 24-epibrassinolide under elevated CO2.

Heavy metals like cadmium (Cd) contamination occur in conjunction with the rising CO2 threatening food security and safety. Foliar application of 24-Epibrassinolide (EBR) was found to ameliorate Cd stress and improve nutrient availability in crops. However, its role under elevated CO2 is currently unknown. Accordingly, a pot experiment was conducted in open-top chambers (CO2 at 400 and 600 μmol mol−1) to determine the protective effect of EBR on wheat plants under different Cd concentrations (0, 2, and 4mgkg-1) in soil. The foliar application of EBR significantly improved growth, biomass, photosynthesis, proline, total phenol, and total soluble protein in Cd stress treatments under elevated CO2. Simultaneously, it significantly (p≤ 0.05) increased catalase (42.89%), superoxide dismutase (26.53%), peroxidase (28.10%), and ascorbate peroxidase (61.70%) while reduced malondialdehyde (35.53%), hydrogen peroxide (19.94%), and electrolyte leakage (23.55%) under elevated CO2 compared to ambient CO2 conditions. Furthermore, EBR and elevated CO2 interactively showed a maximum reduction in Cd concentrations and accumulation in the wheat roots (39.74,41.63%), shoots (46.83,44.87%), and grains (27.52,29.06%) respectively. Elevated CO2 and Cd stress interactively showed a significant reduction in nutrient content. Conversely, the EBR application recovered and significantly increased calcium, magnesium, iron, zinc, and copper content in wheat roots, shoots, and grains. Our findings inferred that EBR foliar application reduced Cd toxicity and improved plant growth and nutritional quality under elevated CO2.

Determination of Metal Cadmium (Cd), Copper (Cu), Iron (Fe) and Zinc (Zn) in Drinking Water from The Boring Well of Surbakti Village, Karo District by Atomic Absorption Spectrophotometry Method

Water is an essential requirement for human existence. In addition to traditional water usage, water is essential for enhancing the quality of human existence and facilitating industrial and technological endeavors. An investigation was conducted on the contents of Cadmium (Cd), Copper (Cu), Iron (Fe), and Zinc (Zn) in drinking water from drilled wells in Surbakti Village, Karo District, employing Atomic Absorption Spectrophotometry (AAS) techniques. Sampling occurred during weeks 1, 2, 3, 4, and 5 and was subsequently digested with concentrated nitric acid until a volume of 15 mL was attained. The metal concentrations of Cd, Cu, Fe, and Zn were quantified using Atomic Absorption Spectroscopy (AAS) using a calibration curve. The findings indicated a concentration of Cd at 0.0031 mg/L, Cu at 0.0470 mg/L, Fe at 0.2741 mg/L, and Zn at 0.2929 mg/L. In this instance, Cd produced a greater concentration of drinking water standards compared to Cu, Fe, and Zn. Nonetheless, it nonetheless met the drinking quality standards established by Regulation Minister of Health No. 492/Menkes/Per/VII/2010.

Fatty Acid Composition, Oxidative Status, and Content of Biogenic Elements in Raw Oats Modified Through Agricultural Practices

The chemical composition of raw oat grain is responsible for the high dietary value and health-promoting properties of oat products. This article presents the results of a study investigating the biofortification of grain in two oat genotypes—hulless and hulled—through agronomic treatments: chemical plant protection against weeds and fungi and mineral nitrogen fertilization. The applied agronomic treatments induced different changes in the fatty acid profiles, content of tocopherols, macronutrients, and micronutrients in the grain of hulled and hulless oats. Plant health contributed to higher concentrations of unsaturated fatty acids and potassium in oat grain. In turn, nitrogen fertilization decreased the content of unsaturated fatty acids, potassium, and copper and increased the content of saturated fatty acids, calcium, and manganese in oat grain. At the same time, agronomic treatments reduced the tocopherol content of the grain, which implies that the nutritional value of oats increases in the absence of chemical plant protection agents. The correlations between the content of desirable chemical compounds and agronomic treatments were stronger in hulless oat grain, which may suggest that the agronomic modification of oat-based foods is more effective in this genotype. The content of exogenous alpha-linoleic acid C18:3 n-3 and alpha-tocopherol was higher in grain harvested from the control treatment (without chemical plant protection), whereas grain harvested from fully protected treatments accumulated more essential gamma-linolenic acid C18:3 n-6. The content of gamma-tocopherol and copper in oat grain was higher in the absence of nitrogen fertilization.

A Systematic Review and Meta-Analysis of the Sustainable Impact of Sewage Sludge Application on Soil Organic Matter and Nutrient Content

The increasing scarcity of natural resources makes the linear production model unsustainable, highlighting the need for more sustainable practices under the umbrella of circular economic principles. Sewage sludge emerges as a promising solution to provide soil organic matter (SOM) and nutrients. This meta-analysis evaluated the impacts of three levels of sludge application (low, medium, and high) on organic matter (OM), nitrogen (N), phosphorus (P), copper (Cu), and zinc (Zn) contents, considering different areas and experimental conditions worldwide. The analysis included 37 studies and 355 comparisons, after screening 7625 records, following the 2020 PRISMA protocol. The effects of sludge concentrations, continents, and types of experiment (field or greenhouse) were evaluated. Sewage sludge application significantly increased OM, N, Cu, and Zn levels, mainly at medium and high rates. The largest effects were observed in greenhouses, suggesting variation by location and environment. Moderators explained a part of the variation in the results, but the residual heterogeneity test revealed that there is still unexplained variability.

Interfacial reaction on different solder composition after laser soldering

AbstractThis study used electroless nickel‐immersion gold surface finish. The lead free solder used are tin‐silver‐copper 305 and tin‐silver‐copper 307 solder alloys. The difference in copper composition will affect the intermetallic compound′s microstructure after the laser soldering process. The intermetallic compound formation analysis reveals that only (Cu, Ni)6Sn5 was observed at the solder joint interface for both solders after laser soldering. The grain microstructure of tin‐silver‐copper 305 formed is rounded‐shaped and bar‐shaped, while tin‐silver‐copper 307 shapes are oval‐shaped and flake‐like. However, for cross‐sectioned analysis, the intermetallic compound grain microstructure formed at the solder joint formation was (Ni, Cu)3Sn4 and (Cu, Ni)6Sn5 presented in dendrite‐like and scale‐like shapes. This result shows that copper content in solder composition is directly affected the intermetallic compound grain microstructure. When exposed to the ageing process, the intermetallic compound thickness will increase directly with ageing time. The intermetallic compound thickness for tin‐silver‐copper 305 was increased from 0.98 μm to 8.34 μm while tin‐silver‐copper 307 was increased from 1.54 μm to 8.76 μm. The result also shows that nano‐sized of Ag3Sn grain particle was formed on the intermetallic compound surface after an ageing process for both samples, tin‐silver‐copper 305 and tin‐silver‐copper 307.

Copper Versatility in Hydroxyapatite: Valence States, Clusters, and Optical Absorption Properties.

The solid-state reaction between a stoichiometric hydroxyapatite (HA) and CuO at temperatures above 1100 °C produces pure Cux-HA phases for x ≤ 0.7 with the general formula Ca10CuIx(PO4)6(OH)2-xOx. The Cu atoms are located at the center of the hexagonal tunnels between two hydroxyl ligands, as determined by Fourier analysis based on XRD data. During heat treatment, the reduction of Cu2+ ions into Cu+ is concomitant with the stabilization of copper in HA in the hexagonal tunnel. The incorporation of monovalent copper within the apatite, as revealed by XANES spectroscopy, explains the violet color of the samples. The incorporation of Cu+ ions, by substitution of a hydrogen atom by copper(I), results in the formation of linear O-Cu-O chains where the majority of which are isolated for x ≤ 0.3. In addition, the EXAFS investigation showed, thanks to the linear geometry of these clusters that results in multiple diffusion effects, the existence of [CuO]n chains with n ≥ 2, which only appear clearly for higher copper contents x ≥ 0.5. The strong covalency of the Cu-O bond in such a dumbbell configuration would lead to strong hybridization between the 3d and 4s orbitals of copper and the 2p orbitals of oxygen, as illustrated by ESR signals. In the case of Cu-doped HA prepared by coprecipitation and annealed at a lower temperature (T ≤ 600 °C), copper substitutes calcium according to the theoretical formula Ca10-xCux(PO4)6(OH)2, mainly at the Ca(2) site. This local environment is in line with the Jahn-Teller distortion induced by the Cu2+ ion (as evidenced by UV-vis-NIR, XPS, and XANES-EXAFS spectroscopy analyses) and also allows copper-copper interactions from one site to another, as observed by ESR spectroscopy. This versatility of copper in HA gives it optical properties that change from a violet color with near-IR absorption to a blue hue. In all cases, Cu-O-Cu interactions persist whatever the valence state, and heat treatment induces a redox phenomenon, with copper exchanging between two sites close to each other.

Molecular complex inspired design of an efficient copper(II)-containing robust porous polymers for electrochemical water oxidation

Homogeneous copper-bipyridine complexes have been reported as effective catalysts for water oxidation, demonstrating significant potential as alternatives to precious metal-based complexes. However, these complexes face long-term stability and product separation challenges similar to many homogeneous catalysts. Meanwhile, recent studies have underscored the potential of metalated polymer networks, which integrate the structural advantages of polymers with the functional benefits of metal species, making them highly attractive for various applications. Herein, we integrated copper-bipyridine units into porous polymer networks to overcome the limitations of copper-bipyridine complexes. We prepared a series of copper-incorporated polymers (TpBpy-Cux) for electrochemical water oxidation. The electrochemical properties of these polymers were tuned by varying the copper content, with TpBpy-Cu3 presenting the best performance among the samples studied. TpBpy-Cu3 demonstrated a low Tafel slope of 69 mV/decade, achieved a high Faradaic efficiency (FE) of 94 %, and exhibited exceptional stability over 1000 cyclic scans. This study offers insights into the design and optimization of metal-incorporated porous polymer networks building on the foundational understanding of their molecular counterparts for advanced catalytic applications.

Carbonate-mediated Mars-van Krevelen mechanism on CuxO/CeO2 catalysts for boosting CO oxidation

Copper-cerium-based catalysts have gained considerable attention for their excellent performance in low-temperature CO oxidation applications. In this context, the carbonate-mediated Mars-van Krevelen (M−vK) pathway stands out as a promising route for enhancing catalytic performance. Herein, we prepared three CuxO/CeO2 nanocatalysts with varying copper content using Cu2O nanocrystals (Cu2O NCs) and Ce-BTC metal–organic frameworks (MOFs) as dual precursors. The optimal catalyst exhibits excellent performance (T100 value of 110 °C) comparable to the precious metal catalyst. Through integrating in-depth experimental results and density functional theory (DFT) calculations, we reveal the intricate interplay of interfacial synergistic catalysis and carbonate-mediated M−vK mechanisms, confirming that carbonate species generated under mild conditions significantly promote CO oxidation on CuxO/CeO2 nanocatalysts. Based on the comparison of the transition state (TS) energy barrier between the traditional and the carbonate-mediated M−vK mechanism reaction paths, we found that carbonate species is easier to form and establish the rate-determining step (viz., carbonate → CO2, the energy barrier of 1.51 eV). This study sheds light on the importance of carbonate species in modulating the catalytic behaviour of copper-cerium catalysts and provides valuable insights for designing efficient catalysts for CO oxidation applications.

A novel fine-grained TiZrCu alloy tailored for marine environment with high microbial corrosion-resistance

Titanium alloys, usually known as non-corrodible material, are susceptible to microbiologically influenced corrosion (MIC) in marine environment. While titanium-zirconium (TiZr) alloys have been extensively studied in medical applications, the influence of microorganisms, especially marine microorganisms, on their corrosion behavior has not been explored. In this work, a TiZrCu alloy with a combination of excellent mechanical, anti-corrosion, and antibacterial properties was developed by optimizing the Cu content and grain refinement. Its MIC and antibacterial mechanisms against Pseudomonas aeruginosa, a representative marine microorganism, were systematically investigated. 5.5 wt% was determined as the optimal copper content. The fine-grained Ti-15Zr-5.5Cu (TZC-5.5FG) alloy maintained high MIC resistance, exhibiting a corrosion current of 5.7 ± 0.1 nA/cm2 and an antibacterial rate of 91.8 % against P. aeruginosa. The mechanism of improved corrosion resistance was attributed to the denser passive film with high TiO2 content and the lower surface potential difference ΔE. The release of Cu2+ ions, ΔE, and the generation of ROS are three major factors that contribute to the antibacterial performance of TiZrCu alloys. Compared to other available marine metals, TZC-5.5FG alloy exhibited superior comprehensive performance, including excellent mechanical properties and anti-MIC capacity, which make it a promising material for load-bearing applications in marine environment.

A Novel Elastomeric Dielectric Materials: Natural Rubber/Copper-Modified Activated Carbon

In this research, a new elastomeric dielectric material is created by integrating natural rubber (NR) with activated carbon derived from coconut shells that has been modified with copper (Ac-Cu). Here, The copper content, ranging from 0 to 2%, was meticulously examined on the AC surface through a reduction technique from copper (II) to copper (0), with the Ac-Cu concentration fixed at 15 parts per hundred of rubber (phr). Systematic investigations into the effects of the additive were conducted across various parameters, encompassing optimum curing time (t90), density, crosslink density, mechanical properties, morphology, and dielectric properties. Results revealed a notable influence of copper on the curing process, resulting in decreased cure time, and a corresponding decrease in crosslink density as the copper content increased. Interestingly, copper incorporation demonstrated a positive impact on mechanical properties. Dielectric property analysis further confirmed a direct effect of increasing copper content on the frequency range of 0.85 to 1.15 GHz. This work not only introduces a pioneering dielectric material but also provides crucial insights into the nuanced effects of copper modification, offering avenues for tailored material design in the realm of enhanced dielectric applications.

Copper Catalysts Anchored on Cysteine-Functionalized Polydopamine-Coated Magnetite Particles: A Versatile Platform for Enhanced Coupling Reactions.

Cysteine plays a crucial role in the development of an efficient copper-catalyst system, where its thiol group serves as a strong anchoring site for metal coordination. By immobilizing copper onto cysteine-modified, polydopamine-coated magnetite particles, this advanced catalytic platform exhibits exceptional stability and catalytic activity. Chemical modification of the polydopamine (PDA) surface with cysteine enhances copper salt immobilization, leading to the formation of the Fe3O4@PDA-Cys@Cu platform. This system was evaluated in palladium-free, copper-catalyzed Sonogashira coupling reactions, effectively catalyzing the coupling of terminal acetylenes with aryl halides. Additionally, the Fe3O4@PDA-Cys@Cu platform was employed in click reactions, confirming the enhanced catalytic efficiency due to increased copper content. The reusability of the platform was further investigated, demonstrating improved performance, especially in recyclability tests in click reaction, making it a promising candidate for sustainable heterogeneous catalysis.

Impact of Row Configuration and Biofertilizers on Yield and Quality of Sorghum (Sorghum bicolor (L.) Moench.) Intercropped with Cowpea in the Southern Laterites of Kerala, India

A field experiment was conducted at the Instructional Farm, College of Agriculture, Vellayani during December 2023 to April 2024 to assess the performance of sorghum in terms of yield and quality, when intercropped with cowpea at varying row configuration and biofertilizers. The field experiment was laid out in Randomized Block Design (RBD). The study comprised intercropping sorghum with cowpea, at three row ratios and four levels of biofertilizer application (r1 – 1:1 row ratio, r2 – 1:2 row ratio, r3 – 2:1 row ratio; b0 – No biofertilizer, b1 – AMF, b2 – Rhizobium and b3 – AMF + Rhizobium). The treatment r3 (2:1 row ratio) resulted in higher grain yield, grains per panicle, grain weight per panicle, and green stover yield of sorghum.19.4 per cent yield increase was observed in the treatment r3 than r2. Application of AMF and Rhizobium together (b3) resulted in more number of grains per panicle, grain weight, grain yield and green stover yield of sorghum. Sorghum grain yield was reduced in the absence of biofertilizer (b0). The treatment combination r2b1 (sorghum intercropped with cowpea in 1:2 ratio along with AMF) showed the highest crude protein content in sorghum grains. Iron and copper content were increased with the application of AMF (b1). However, application of AMF and Rhizobium (b3) together resulted in higher magnesium content in sorghum grains.

A Study on the Potential for the Application of Peanut Shells as a Reducer in the Process of Metal Recovery from Metallurgical Slags

Copper production technology is a complex process consisting of many stages. The combination of pyrometallurgical and hydrometallurgical stages, on the one hand, complicates production while, on the other hand, allowing for a relatively selective separation of intermediate or waste materials that can be subjected to the process of recovery of useful components. Materials of this type are characterised by a much higher copper content relative to the ore material. On the other hand, due to the oxide form, reduction processes are used in which coke is mainly applied. Reduction of the unfavourable phenomenon of CO2 emissions, in this case, can be performed through the use of bioreducers, which are characterised by an inert carbon footprint since the generation of carbon dioxides is the same as its absorption at the stage of vegetation and growth. In this paper, the topic of determining the feasibility of using selected bioreducers, such as peanut shells, to verify their suitability in the process of reducing copper oxides as well as the impact on the working components of the laboratory reactor in which the process is carried out are discussed. In this case, raw materials with a composition similar to the that of slags produced at the copper production stage in a flash furnace were tested for reduction. The results referring to reducing lead and copper contents above 88% Pb and 98% Cu indicate the great potential of this type of bioreducer. An additional advantage is the relatively wide availability of peanut resources. The effects of the copper reduction time on the degree of decopperisation performed with a constant reducer addition at 1300 °C were studied in this paper. Following 1 h of the process, the copper content in the slag was 0.78 wt%, while the longer process duration resulted in a copper fraction of 0.19 wt%. Considering lead, its content was 0.33 wt% after the reduction process.

Nanowires made of ternary alloys – synthesis features and magnetic properties

Nanowires of FexCoyCu(100–x–y) and FexNiyCu(100–x–y) alloys have been studied. The features of obtaining such structures by the matrix synthesis method have been investigated. Elemental analysis of nanowires grown at sequentially increasing voltages revealed a significant decrease in the amount of copper, as well as a change in the ratio of the main magnetic elements. X-ray phase analysis showed that FeCoCu is a three-component solid solution, while FeNiCu contains three phases of solid solutions: FeCu with copper content up to 80%, FeNi with high iron content, and NiCu in an amorphous or fine-crystalline state with nickel content up to 80%. Mössbauer spectroscopy revealed that the addition of copper can lead to a change in the angle of magnetic moment misalignment in nanowires, which correlates with magnetometry data.

Effect of pre-exposure to chloride environment on the tensile deformation of SS 304HCu at 973 K

304HCu austenitic stainless steel (SS 304HCu) with 3 % copper content is utilized as the tubing material for advanced ultra-supercritical boilers, which operate at temperatures around 973 K and a pressure of 31 MPa. The current investigation aimed to examine the influence of prior exposure to an acidic chloride environment on the tensile characteristics of SS 304HCu at 973 K with the nominal strain rate of 1× 10−3 s−1 in solution annealed as well as thermally aged (973 K/10000 h) conditions. In the prior exposure condition, both the solution annealed and aged specimens were subjected to a pre-determined potential of −0.14 V (Ag/AgCl) for 48 h in 5 M NaCl + 0.15 M Na2SO4 + 2 ml HCl solutions. Thermally aged SS 304HCu showed lower strength in both true UTS and true yield strength compared to the solution annealed specimen tested at 973 K. Exposure to an acidic environment resulted in a considerable reduction in tensile strength and uniform plastic strain. For all the conditions, saturation-stress-based relationship was employed to describe the flow behaviour of the alloy. The relationship adequately fits the true stress-true strain data of SS 304HCu. A systematic variation in strain hardening parameters with respect to different test conditions is noticed. In the case of the aged alloy, the observed microstructure revealed the presence of M23C6 at grain boundaries and copper precipitates in the grain interior. The increased chromium depletion and the higher degree of sensitization led to the formation of localized pits in pre-exposed aged specimen conditions. Consequently, the synergistic influence of precipitation and pitting corrosion significantly affected the tensile deformation behaviour of SS 304HCu alloy in the aged and pre-exposed condition compared to the solution annealed condition.

Performance of poplars and willow grown on soil under wastewater irrigation during the first 2 years of establishment.

Recycling wastewaters as irrigation and fertilization of tree species is a market-driven action for purpose-grown timber plantations that promotes the circular economy. A greenhouse experiment was carried out to investigate the performance of poplar clones (Populus alba L. "20/45", P. nigra L. "62/154", and P. euramericana (Dode) Guinier "92/40") and willow (Salix excelsa S.G. Gmel) grown on soils under tap water irrigation (TWI) or wastewater irrigation (WWI) during the first 2 years of establishment. Results showed that at 2 years after planting, poplars and willow exhibited significantly greater performance when grown in WWI versus TWI (P < 0.05). Likewise, phytoremediation of nutrients along with some heavy metals increased in plant organs of WWI-grown plants relative to their TWI counterparts (P < 0.05). After 2 years of growth and under both conditions (TWI and WWI), P. nigra plants showed the greatest growth and biomass; however, leaf area was the largest for P. alba and P. euramericana plants. Also, P. nigra plants had the highest total contents of copper (Cu) and manganese (Mn), P. alba had the most zinc (Zn), and differences for iron (Fe) were negligible across species. In contrast, total contents of nickel (Ni) and chromium (Cr) were higher for S. excelsa, P. nigra, and P. alba plants, while the lowest values were measured in P. euramericana plants. Across all species and soil treatments, the translocation factor (TF) was greater than 1 for Mn, Cu, and Zn, indicating phytoextraction and phytoaccumulation of these elements into leaves and stems, while TF was less than 1 for Fe, lead (Pb), Ni, and Cr, resulting in phytoremediation of these elements as phytostabilization. Differences in tolerance index (TI) values were negligible across species, and TI was greater than 100% after 2 years of growth, indicating that all four species are suitable for phytoremediation applications with urban wastewaters having similar heavy metal concentrations as in the present study. Nevertheless, given the combination of enhanced growth, biomass, and heavy metal accumulation (Mn, Cu, Cr, and Ni), P. nigra plants exhibited the greatest phytoremediation potential of four tested species.

Copper supplementation alleviates hypoxia‑induced ferroptosis and oxidative stress in neuronal cells.

Hypoxic ischemia is the primary cause of brain damage in newborns. Notably, copper supplementation has potential benefits in ischemic brain damage; however, the precise mechanisms underlying this protective effect remain unclear. In the present study, a hypoxic HT22 cell model was developed to examine the mechanism by which copper mitigates hypoxia‑induced oxidative stress. Cell viability was assessed using the Cell Counting Kit‑8 assay, mitochondrial structure was examined with a transmission electron microscope, intracellular ferrous ions and lipid reactive oxygen species levels in HT22 cells were measured using FerroOrange and BODIPY 581/591 C11 staining, copper content was determined using graphite furnace atomic absorption spectroscopy, and gene and protein expression were analyzed by reverse transcription‑quantitative PCR and western blotting. The present findings indicated that hypoxic exposure may lead to reduced cell viability, along with the upregulation of various markers associated with ferroptosis. Furthermore, hypoxia elevated the levels of reactive oxygen species, hydrogen peroxide and malondialdehyde, and decreased the activity of superoxide dismutase 1 (SOD1) in HT22 cells. In addition, the intracellular copper concentration exhibited a notable decrease, while supplementation with an appropriate dose of copper effectively shielded neurons from hypoxia‑induced oxidative stress and ferroptosis, and elevated cell viability in hypoxia‑exposed HT22 cells through the copper chaperone for superoxide dismutase/SOD1/glutathione peroxidase 4 axis. In conclusion, the present study identified a novel function of copper in protecting neurons from oxidative stress and ferroptosis under hypoxic conditions, providing fresh insights into the therapeutic potential of copper in mitigating hypoxia‑induced neuronal injury.

Effects of heavy alkali metals (Rb, Cs) post-deposition treatments on CuInGaSe2 using a spin-coating technique

Abstract This study used a controlled environment to explore the post-deposition treatment (PDT) effects on CuInGaSe2 (CIGSe2) semiconducting thin films using a non-vacuum spin-coating technique for doping the CIGSe layers with Cs and Rb. The structural characterization confirmed the successful deposition of chalcopyrite structures with no phases belonging to any alkali metals after the PDT, with crystallite sizes in the range between 40-67 nm, and with a slight change in the X Ray Diffraction (XRD) peak positions indicating a change from copper-rich to copper-poor phases. The morphological studies confirmed the increase in grain sizes after the PDT. The EDS chemical studies showed that there is a reduction in the copper content after PDT. The topographical studies showed a change in the surface morphology with modifications of the grain parameters. In addition, the electrical characterization showed a significant increase of the effective carrier mobility after the treatments, consistent with the grain size increase observed by both microscopic (SEM and AFM) studies. Raman characterization of the CIGSe2 films showed the A1 optical phonon mode of CIGS chalcopyrite structures and peaks at lower frequencies belonging to ordered vacancy compounds (OVCs). The deconvolution of the Raman spectroscopy broad peaks for the CIGSe2 films after their PDT confirmed the formation of alk-InSe2 OVC phases on top of the absorber layer.

Study on the Changes in the Microbial Community in Rhizosphere Soil of Blueberry Plants at Different Growth Stages

In order to clarify the relationship between mineral nutrients and rhizosphere microorganisms at different growth and development stages of blueberry (Vaccinium spp.), this work studied the dynamic changes in element content and microbial quantity in different parts of blueberry plants. The test material was a 12-year-old half-highbush blueberry variety (‘Beilu’). The changes in the mineral nutrient elements in leaves, branches and the soil of blueberry plants were studied at the full bloom stage (T1), green fruit stage (T2), mature stage (T3) and late mature stage (T4), and the correlations of the average contents of mineral elements in the four periods were studied. The bacterial community in the rhizosphere soil was determined and analyzed using 16S rRNA high-throughput sequencing technology. The results showed that the changes in other mineral elements in various parts of blueberry plants varied in different periods. Nitrogen (N) showed a downward trend in branches, leaves and soil, especially in leaves (p &lt; 0.05). The N contents in T2, T3 and T4 decreased by 9.9%, 26.4% and 29.9%, respectively. The N contents in the leaves and branches showed a downward trend at different growth stages, especially in leaves. The phosphorus (P) content in leaves showed a trend of increasing first and then decreasing, while it continued to increase in branches. The content of potassium (K) in leaves changed significantly, where it increased first and then decreased. The content of calcium (Ca) in leaves decreased first and then increased, while the content of magnesium (Mg) in branches and leaves decreased first and then increased, and the relative change was significant. The contents of iron (Fe) and zinc (Zn) in leaves decreased first and then increased, while the contents of manganese (Mn) and copper (Cu) were relatively stable. Cu decreased first and then increased in leaves and soil, and it increased first and then decreased in branches. The mineral nutrients in different growth stages of blueberry showed significant correlation in leaves, branches and soil. Mn in leaves was significantly positively correlated with P, Ca, Mg, Mn, Cu and Zn in soil (p &lt; 0.01). Nitrogen and calcium in leaves were significantly correlated with manganese and phosphorus in soil, respectively. Ca in branches was significantly positively correlated with N and K in soil and was significantly positively correlated with Zn in soil (p &lt; 0.01). Magnesium was significantly negatively correlated with iron in soil. The bacterial community structure of the blueberry rhizosphere soil changed significantly over time (p &lt; 0.05), and the relative abundance showed the following trend: T4 &gt; T2 &gt; T3 &gt; T1. At the phylum level, Proteobacteria, Acidobacteria, Actinobacteria, Chloroflexi and Verrucomicrobia were the dominant bacteria in different periods. Candidatus solibacter and Bryobacter were significantly higher in T1 and T3 than in T1 and T4. Bradyrhizobium flora increased significantly at T3. Sphingomonas increased significantly at T1 (p &lt; 0.05).

Plant growth promoting bacteria promote rice growth cultivated in two different sandy soils subjected distinct climates conditions.

Sandy soils contain around 70% sand in their composition, making them highly fragile and susceptible to land degradation. Practices such as no-tillage cultivation, the use of bioinoculants, and the application of organic amendments can restore the organic matter in these soils, ensuring sustainable production. In this context, this work aimed to study the microbiological aspects of two sandy soil areas (Brazilian Northeast and South) under contrasting climatic conditions (tropical and temperate). With this purpose, prokaryotic communities were evaluated, and the plant growth-promoting potential of isolated bacteria was assessed by rice inoculation in sandy soil. Despite the high sand content in both soils, soil from the NE was related to the highest phosphorous, calcium, potassium, copper, sodium, zinc, magnesium, and manganese contents, organic matter percentage, and pH. The Shannon diversity index indicated that prokaryotic communities in NE were more diverse than in SU, and PCA revealed that microbial composition exhibited distinct patterns. The rice inoculation experiments were executed to verify if the bacterial isolates displayed a similar growth promotion potential when inoculated in sandy soil areas subjected to different climatic conditions. When all PGP characteristics evaluated were pooled in a PCA, a similar pattern was observed for SU and NE. Burkholderia sp. SU94 was related to highest PGP characteristics evaluated. Paraburkholderia sp. NE32 showed similar results to those of the non-inoculated control. This similar effect of rice growth in the Northeast and South of Brazil suggests that isolate SU94 adapts to different environmental conditions.