Calcium Nitrate Research Articles

Highly efficient and eco‐friendly enhancement of polyvinyl chloride thermal stability: A renewable cinnamate‐intercalated calcium aluminum hydrotalcite stabilizer

AbstractWith the development of green chemistry, PVC thermal stabilizers should be developed in the direction of non‐toxic, environmental protection, and high efficiency. This study utilized natural Cinnamic acid to successfully synthesize an eco‐friendly and high‐performance cinnamate‐intercalated calcium aluminum hydrotalcite through the coprecipitation method. The structure of CaAl‐cinnamate‐LDHs was analyzed via XRD, IR, SEM, and thermogravimetric analyses. The CaAl‐cinnamate‐LDHs/PVC sample was thoroughly investigated using multiple techniques, including tests, such as oven aging, thermogravimetric analysis, Congo red analysis, and conductivity analysis. Compared with the commercial thermal stabilizers CaSt2/ZnSt2 and CaAl‐CO3‐LDHs, CaAl‐cinnamate‐LDHs demonstrated superior initial whiteness and exceptional long‐term thermal stability, it did not completely blacken until 120 min. Dynamic mechanical analysis showed that the addition of CaAl‐cinnamate‐LDHs could improve the plasticizing performance of PVC. CaAl‐cinnamate‐LDHs also had a synergistic effect with ZnSt2, with a static thermal stabilization time of up to 40.5 min. Through HCl absorption experiments to investigate the thermal stabilization mechanism, the results showed that CaAl‐cinnamate‐LDHs can effectively absorb HCl released during PVC degradation.Highlights By utilizing natural organic Cinnamic acid, Calcium nitrate, and Aluminum nitrate as raw materials, all from a wide range of sources, the reaction process eliminated the need for toxic solvents and a large number of chemicals. The preparation process of CaAl‐cinnamate‐LDHs was simple and the reaction time was short. Comprehensive tests showcased the exceptional long‐term thermal stability of the CaAl‐cinnamate‐LDHs/PVC sample. The addition of CaAl‐cinnamate‐LDHs can improve the plasticizing property of PVC. The mechanism of CaAl‐cinnamate‐LDHs was capable of absorbing HCl released during PVC degradation.

A novel and facile synthesis of calcium silicate nanoparticles as a base for root canal cement/sealer under constant potential: Compared to chemical synthesis

Among inorganic biomaterials, which recently have received great attention in regenerative medicine, calcium silicate-based cements are bioactive materials that are prepared based on a composition of calcium and silicate. This manuscript explores the synthesis of pure calcium silicate (CaSiO3) nanoparticles using two different methods: sol-gel synthesis and electrochemical synthesis. The goal is to compare the structural characteristics of the synthesized products. In the sol-gel method, CaSiO3 is prepared using tetraethyl orthosilicate (TEOS) and calcium nitrate tetrahydrate, while in the electrochemical method; CaSiO3 is synthesized under constant potential using the same materials. The resulting nanoparticles were characterized using various analytical techniques such as scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction analysis (XRD). Additionally, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were performed. The XRD analysis revealed crystal sizes of 21 nm and 39.94 nm for electrochemical and chemical synthesis, respectively, indicating the formation of wollastonite-type CaSiO3 in the electrochemical method. SEM analysis showed average particle sizes of 62.44 nm and 119 nm for electrochemical and chemical synthesis, respectively. The results demonstrate that the proposed electrochemical method offers a simple, rapid, inexpensive, and high-purity approach for the synthesis of CaSiO3, which can serve as an alternative to chemical methods. The findings of this study contribute to the development of biomaterials for dental and medical applications.

Nutrient recovery from wastewater for hydroponic systems: A comparative analysis of fertilizer demand, recovery products, and supply potential of WWTPs

Nutrient recovery from wastewater treatment plants (WWTPs) for hydroponic cultivation holds promise for closing the nutrient loop and meeting rising food demands. However, most studies focus on solid products for soil-based agriculture, thus raising questions about their suitability for hydroponics. In this study, we address these questions by performing the first in-depth assessment of the extent to which state-of-the-art nutrient recovery processes can generate useful products for hydroponic application. Our results indicate that less than 11.5% of the required nutrients for crops grown hydroponically can currently be recovered. Potassium nitrate (KNO3), calcium nitrate (Ca(NO3)2), and magnesium sulfate (MgSO4), constituting over 75% of the total nutrient demand for hydroponics, cannot be recovered in appropriate form due to their high solubility, hindering their separated recovery from wastewater. To overcome this challenge, we outline a novel nutrient recovery approach that emphasizes the generation of multi-nutrient concentrates specifically designed to meet the requirements of hydroponic cultivation. Based on a theoretical assessment of nutrient and contaminant flows in a typical municipal WWTP, utilizing a steady-state model, we estimated that this novel approach could potentially supply up to 56% of the nutrient requirements of hydroponic systems. Finally, we outline fundamental design requirements for nutrient recovery systems based on this new approach. Achieving these nutrient recovery potentials could be technically feasible through a combination of activated sludge processes for nitrification, membrane-based desalination processes, and selective removal of interfering NaCl. However, given the limited investigation into such treatment trains, further research is essential to explore viable system designs for effective nutrient recovery for hydroponics.

The effect of various water-soluble fertilizers on the productivity of potato plants of the Dochka variety in aeroponics

The possibility and the prospects of using various water-soluble fertilisers for growing healthy planting material of potato variety Dochka under aeroponics conditions have been studied. Two variants of water-soluble fertilisers were used as objects of study: 1) Nutriflex-T complex fertiliser at a concentration of 2 g/l with the addition of calcium nitrate 4-aqueous at a concentration of 0.35 g/l; 2) author's water-soluble fertiliser Martirosyan Yu.Ts. At a concentration of 1 g/l. In the experiments, healthy potato microplants of the Dochka variety were used. The experiments were carried out on aeroponic systems "Urozhay-9000". Sodium sodium-vapour lamps DNAT 400 were used as a light source. After 30 days of cultivation on a water-soluble fertiliser, the height of potato plants and the length of the root system in the studied variants did not differ in the version using the author's environment, Martirosyan Yu.Ts. Compared with the variant with the use of the Nutriflex-T complex fertiliser, a statistically significant increase in the following indicators was observed: the average number of mini tubers obtained from one plant (17.38±0.29 pcs. pieces/bush compared to 14.44±0.35 pieces/bush), the average weight of one mini tuber (8.17±0.29 g compared to 5.47±0.26 g), the proportion of mini tubers weighing over 4 g (67.63% compared to 46.10%), biomass of the root system at the end of cultivation (33.31±0.45 g compared to 30.31±0.35 g). At the same time, the biomass of the vegetative part of potato plants at the end of cultivation on the Nutriflex-T fertiliser was higher than the biomass of the vegetative part of plants grown on the nutrient medium of Martirosyan Yu.Ts. (284.06±4.77 g compared to 151.25±2.45 g). It is shown that the cultivation of potato plants of the Dochka variety on the author's water-soluble fertiliser Martirosyan Yu.Ts. It is economically viable.

Integrated Nutrient Management as a Low Cost and Eco-Friendly Strategy for Sustainable Fruit Production in Apricot (Prunus armeniaca L.)

ABSTRACT Prolonged and excessive use of chemical fertilizers has resulted in serious harm to soil health and ecosystems. This study aimed to reduce the cultivation costs for apricot trees, nearly 1/3rd of which are spent on fertilizers. The research was conducted on fully grown apricot trees of the cultivar “New Castle,” in the Solan district of Himachal Pradesh, India. The experiment consisted of fourteen treatment combinations evaluated in triplicate and statistically analyzed using a randomized block design (RBD). Results revealed that treatment T12 [50% Nitrogen (Calcium Nitrate) + 50% Nitrogen (Urea) + Azotobacter + Phosphate Solubilizing Bacteria + Vermicompost] resulted in the highest percent increase in tree trunk girth (6.82%), highest leaf chlorophyll content (3.00 mg g−1 fresh weight), leaf area (58.29 cm), fruit set (61.00%) and total yield (61.9 kg tree−1). In terms of nutrient status, T12 had the highest leaf N (2.95%), leaf K (2.60%), soil N (386.33 kg ha−1), soil P (51.00 kg ha−1) and soil organic carbon (1.81%). The highest net return and profit over recommended dose of fertilizers (RDF) was also recorded in treatment T12. The results of this study show that judicious fertilizer use along with integrated organic manure and bio-fertilizers can reduce cultivation costs, improve soil health, and increase fruit production with minimum ecosystem damage.

Mixed ensiling plus nitrate destroy fiber structure of rape straw, increase degradation, and reduce methanogenesis through in vitro ruminal fermentation.

Better utilization of rape straw can provide alternative strategies for sustainable ruminant and food production. The research reported here investigated changes in the carbohydrate composition of rape straw as a result of mixed ensiling with whole-crop corn or inoculated with nitrate, and the consequent effects on ruminal fermentation through in vitro batch culture. The three treatments included: rape straw and corn silage (RSTC), and ensiling treatment of rape straw with whole-crop corn (RSIC) or with calcium nitrate inoculation (RSICN). Ensiling treatment of rape straw and whole-crop corn or plus nitrate enriched lactic acid bacteria and lactate. The treatments broke the fiber surface connections of rape straw, leading to higher neutral detergent soluble (NDS) content and lower fiber content. Ensiling treatments led to greater (P < 0.05) dry matter degradation (DMD), molar proportions of propionate and butyrate, relative abundance of the phylum Bacteroidetes and genus Prevotella, and lower (P < 0.05) methane production in terms of g kg-1 DMD, molar proportions of acetate, and lower acetate to propionate ratio than the RSTC treatment. The RSICN treatment led to the lowest (P < 0.05) hydrogen concentration and methane production among the three treatments. Ensiling treatments of rape straw and whole-crop corn destroy the micro-structure of rape straw, promote substrate degradation by enriching the phylum Bacteroidetes and the genus Prevotella, and decrease methane production by favoring propionate and butyrate production. Nitrate inoculation in the ensiling treatment of rape straw and whole-crop corn further decreases methane production without influencing substrate degradation by providing an additional hydrogen sink. © 2023 Society of Chemical Industry.

Impact of nitrogen fertilizer type and application rate on growth, nitrate accumulation, and postharvest quality of spinach.

A balanced supply of nitrogen is essential for spinach, supporting both optimal growth and appropriate nitrate (NO3 -) levels for improved storage quality. Thus, choosing the correct nitrogen fertilizer type and application rate is key for successful spinach cultivation. This study investigated the effects of different nitrogen (N) fertilizer type and application rates on the growth, nitrate content, and storage quality of spinach plants. Four fertilizer types were applied at five N doses (25, 50, 200, and 400 mg N kg-1) to plants grown in plastic pots at a greenhouse. The fertilizer types used in the experiment were ammonium sulphate (AS), slow-release ammonium sulphate (SRAS), calcium nitrate (CN), and yeast residue (YR). Spinach parameters like Soil Plant Analysis Development (SPAD) values (chlorophyll content), plant height, and fresh weight were measured. Nitrate content in leaves was analyzed after storage periods simulating post-harvest handling (0, 5, and 10 days). The application of nitrogen fertilizer significantly influenced spinach growth parameters and nitrate content. The YRx400 treatment yielded the largest leaves (10.3 ± 0.5 cm long, 5.3 ± 0.2 cm wide). SPAD values increased with higher N doses for AS, SRAS, and CN fertilizers, with AS×400 (58.1 ± 0.8) and SRAS×400 (62.0 ± 5.8) reaching the highest values. YR treatments showed a moderate SPAD increase. Fresh weight response depended on fertilizer type, N dose, and storage period. While fresh weight increased in all fertilizers till 200 mg kg-1 dose, a decrease was observed at the highest dose for AS and CN. SRAS exhibited a more gradual increase in fresh weight with increasing nitrogen dose, without the negative impact seen at the highest dose in AS and CN. Nitrate content in spinach leaves varied by fertilizer type, dose, and storage day. CNx400 resulted in the highest NO3 - content (4,395 mg kg-1) at harvest (Day 0), exceeding the European Union's safety limit. This level decreased over 10 days of storage but remained above the limit for CN on Days 0 and 5. SRAS and YR fertilizers generally had lower NO3 - concentrations throughout the experiment. Storage at +4 °C significantly affected NO3 - content. While levels remained relatively stable during the first 5 days, a substantial decrease was observed by Day 10 for all fertilizers and doses, providing insights into the spinach's nitrate content over a 10-day storage period. For rapid early growth and potentially higher yields, AS may be suitable at moderate doses (200 mg kg-1). SRAS offers a more balanced approach, promoting sustained growth while potentially reducing NO3 - accumulation compared to AS. Yeast residue, with its slow nitrogen release and consistently low NO3 - levels, could be a viable option for organic spinach production.

O uso de fertilizantes nitrogenados por plantas de citrus é afetado por diferentes proporções de nitrato e amônio

Abstract: Nitrogen (N) fertilization in citrus orchards is prone to significant environmental losses. Managing nutrients for sustainable development and optimizing nitrogen use efficiency (NUE) are key tasks in modern agriculture. NUE depends on N uptake and assimilation. In addition to intrinsic fertilizer use efficiency, we evaluated plant growth, nitrate reductase (NRase) activity, and the nutritional status of citrus plants fertilized with different N sources [calcium nitrate (CN), ammonium nitrate (AN), and ammonium sulfate (AS)]. After 240 days, plants supplied with either CN or AN exhibited higher biomass production and N accumulation in the leaves than those fertilized with AS. The supply of ammonium-containing sources (AN and AS) reduced the substrate pH, in which those with AS exhibited lower N partitioning to the leaves, as well as reduced the absorption and accumulation of magnesium and phosphorus. NRase activity was higher in plants supplied with CN or AN compared to AS, and CN fertilization provided the greatest NUE. The data demonstrated that citrus plants fertilized with sources containing nitrate increased the NUE from 10 to 25% and consequently had greater growth compared to those fed with AS.

Synthesis and Comparison of Chemical Changes for Novel Silver Substituted Hydroxyapatite using Fourier Transform InfraRed Rays

The aim of the study is to synthesize and compare the chemical changes using FTIR for silver substituted hydroxyapatite. Different types of silver substituted hydroxyapatite are used. Ammonium hydroxide solution is combined with calcium nitrate tetrahydrate (Ca(NO3)2·4H2O), silver chloride hexahydrate (AgCl2.6H2O), diammonium hydrogen phosphate ((NH4)2HPO4), and ammonium hydroxide (HN4OH) solutions. The precipitation method was carried out using the ultrasonic. With the use of clinclac.com, the total sample size was determined for the silver substituted data (N=4), alpha error of 0.05, G power of 80%, enrollment ratio of 0:1, confidence interval of 95%, and total sample size of 4. There is a statistical significance existence, P=0.004, (p&lt;0.05).This shows that there is a statistical significant difference between the two groups considered in this study. When compared to other percentages, 10% of silver substituted hydroxyapatite exhibits better properties. It is concluded that the 10% of silver doped hydroxyapatite is more efficient and exhibits better properties than other substitutions. It can be very used in bone regeneration, structural strength and dental implants.

Synthesis and Comparison of Chemical Changes Using FTIR Spectroscop for Copper Substituted Hydroxyapatite

The study aims to scrutinise and compare the chemical modifications present in copper-substituted hydroxyapatite utilising FT-IR spectroscopy. The synthesis of both HAp and Cu-modified HAp was conducted via the chemical precipitation method, involving specific chemicals like ammonium hydroxide (HN4OH) solution, diammonium hydrogen phosphate ((NH4)2HPO4), copper chloride hexahydrate (CuCl2.6H2O), and calcium nitrate tetrahydrate (Ca(NO3)2.4H2O). The overall sample size was determined through clinlac.com considering the copper-substituted dataset (N=4), an alpha error of 0.05, G power at 80%, an enrolment ratio of 0.1, and a confidence interval of 95%. The acquired FT-IR spectra denote minimal differences between the CuHAp and HAp samples. Each peak bears a resemblance to the distinctive features of HAp, indicating structural similarity between pure hydroxyapatite and the copper-substituted variant. The investigation utilised SPSS 27.0.1 software to compute the copper-doped hydroxyapatite percentages at 0%, 1%, 5%, and 10%. A One Sample T-test revealed a statistically significant difference with a p-value of 0.001 (p&lt;0.05), particularly highlighting the statistical significance of copper hydroxyapatite weight percentage (p=0.006). Significant alterations in peak values were observed in the novel copper-substituted hydroxyapatite concentrations of 1%, 5%, and 10%. Notably, the study identifies the 10% copper and hydroxyapatite combination as yielding the most noteworthy chemical modifications via spectroscopy. This finding suggests the potential utility of these compounds in medicinal applications.

Prevention of White Spot Lesion during Orthodontic Treatment: A Novel Bioactive Glass Nanobioadhesive

Objectives: The objective of this study is to evaluate the ability of the bioactive glass (BAG)-Bonds to inhibit the demineralization surrounding the orthodontic brackets when being exposed to an in vitro caries challenge and also simultaneously evaluate the physical and mechanical properties in order to be accepted as an orthodontic bonding agent. Materials and Methods: Preparation of mesoporous bioactive glass (MBG) used an improved sol-gel method, combining with sacrificial liquid template to MBGs with controllable particle size. Tetraethyl orthosilicate, triethyl phosphate, calcium nitrate tetrahydrate, ethanol absolute, ethyl acetate, hexadecyltrimethylammonium bromide, deionized water, and ammonium hydroxide were used. The microstructure was analyzed using a field emission gun-based scanning electron microscope (SEM). The debonding and adhesion characteristics were analyzed using an Instron Universal Testing Machine. Results: SEM analysis shows that the prepared MBG particles possess spherical morphology with generally uniform size. Novel orthodontic bonding material (BG) provides adequate mechanical and physical properties in order to be accepted as an orthodontic bonding agent since its bond strength both at the time of bonding and after 6 months in simulated salivary conditions is significantly higher than conventional bonding resin (TBXT). The bond strength was also evaluated both initially at the time of bonding as well as 6 months after being kept in simulated salivary conditions. Conclusion: These novel adhesives result in reduced demineralization surrounding orthodontic brackets and possess optimal physical and mechanical properties to be accepted as an orthodontic adhesive.

Research new type of cation-exchange resin for waste water treatment

This article presents the studies obtaining and research new polycondensation type phosphoric cation-exchange resin. The conditions for the phosphorylation of this polymer were selected from the experiments accumulated in relation to the phosphorylation reactions of low- and high-molecular compounds. The resulting polymer had an exchange capacity for a 0.1 N NaOH solution – 5,5-5,6 mEq/g and contained 16,5% phosphorus. Based on the studies carried out, the optimal conditions for the synthesis of the styrene-furfural polymer are assumed to be: the reaction temperature is 90°C, the concentration of the ZnCl2 catalyst is 0.07 mol per mole of furfural, and the molar ratio of styrene to furfural is 1:1. There was studied an interaction of the cation exchanger in Na- and H-forms with solutions of salts of copper sulfate, nickel, cobalt, sodium chloride, calcium and uranyl nitrate. In order to elucidate the mechanism of sorption of the cations of these metals, were taken the IR-spectra of the cation exchanger in the H- and Na- form, saturated with copper ions. The less dissociated phosphoric acid groups, the stronger hydrogen bond forms phosphoryl oxygen with OH-groups. Therefore, it can be expected that as the cation exchanger is saturated with sodium, the maximum of the band corresponding to the phosphorus-oxygen bond vibrations will slightly shift to longer wavelengths as a result of the destruction of the weaker hydrogen bond.

Assessment of Calcium Nitrate Fertilizer as a Suitable Nitrogen Source for Cacao (Theobroma cacao L.) Cultivation in Ghana

Assessment of Calcium Nitrate Fertilizer as a Suitable Nitrogen Source for Cacao (<i>Theobroma cacao</i> L.) Cultivation in Ghana

Water Quality Monitoring for Smart Farming Using Machine Learning Approach

Water quality in fish farming environments has been a topic of research investigation for numerous years. While most studies have concentrated on managing water quality in fish ponds, there is a lack of research on implementing these practices on a commercial scale. Maintaining good water quality helps prevent disease, stress, and death in fish, resulting in higher yields and profits in fish farming operations. In our study, we gathered weekly data from two fish ponds in the Lintangsongo smart farming area over six months. To deal with the limited dataset, we utilized methods for reducing dimensionality, like the pairwise comparison of correlation matrices to eliminate the highest correlated predictors. We used techniques of feature selection, including XGBoost classification, and apart from that, we used Recursive Feature Elimination (RFE) to determine the importance of features. This analysis identified ammonium and calcium as the top two predictors. These nutrients played a vital role in maintaining the paired cultivation system and promoting the robust development of Nile tilapia fish and water spinach. This process of detecting and distributing nutrients persists until the desired quantities of ammonium and calcium are reached. During each cycle, 0.7 g of ammonium sulfate and calcium nitrate are distributed, and the nutrient levels are assessed. Vernier sensors were employed for assessing nutrient values, and a system of actuators was integrated to supply the necessary nutrients to the smart farming environment using the closed-loop concept. This research investigates water quality management practices in fish farming, assesses their impact on fish health and profitability, identifies key water quality predictors, and implements a closed-loop system for nutrient delivery.

Nitrous oxide emissions and N-cycling gene abundances in a drip-fertigated (surface versus subsurface) maize crop with different N sources

Surface drip fertigation has demonstrated promising results regarding the mitigation of nitrous oxide (N2O) emissions. The use of subsurface irrigation may offer the possibility of reducing these emissions further due to the modification of the soil moisture profile and N allocation, both of which affect the biochemical processes leading to N2O fluxes. However, the mitigation potential of subsurface irrigation combined with different mineral nitrogen (N) fertilizers (ammonium or nitrate-based, use of nitrification inhibitors) still needs to be evaluated. To respond to this need, a 2-year field experiment was set up in central Spain to test two different drip-fertigation systems (surface and subsurface at 30 cm depth) and four N fertilization treatments (control, calcium nitrate, and ammonium sulfate with or without the nitrification inhibitor 3,4-dimethylpyrazole phosphate, DMPP) in an irrigated maize (Zea mays L.) crop. Nitrous oxide emissions, mineral N concentrations (ammonium, NH4+, and nitrate, NO3−), and abundance of key N genes involved in nitrification and denitrification processes were measured in two soil layers (0–20 and 20–40 cm). Regardless of the irrigation system, ammonium sulfate gave the highest cumulative N2O losses in both campaigns, while calcium nitrate and the use of DMPP were the most effective strategies to abate N2O fluxes in the first and second years, respectively. Differences between irrigation systems were not statistically significant for cumulative N2O emissions, despite the clear effect on topsoil mineral N (higher NH4+ and NO3− concentrations in surface and subsurface drip, respectively). Nitrous oxide emissions were positively correlated with soil NH4+ concentrations. Gene abundances were not a trustworthy predictor of N2O losses in the 1st year, although a clear inhibitory effect of fertilization on microbial communities (i.e., ammonia oxidizers, nitrite reducers, and N2O reducers) was observed during this campaign. During the second year, nitrifying and denitrifying genes were affected by irrigation (with higher abundances in the 20–40 cm layer in subsurface than in surface drip) and by the addition of DMPP (which had a detrimental effect on gene abundances in both irrigation systems that disappeared after the fertigation period). In conclusion, the use of DMPP or calcium nitrate instead of ammonium sulfate may enhance the chances for an additional mitigation in both surface and subsurface irrigation systems.

Synthesis and characterization of Zn-modified hydroxyapatite photoactive composites from eggshell residues for bone regeneration

Photoactive composites based on hydroxyapatite containing zinc (HAp-Zn x%, x = 0, 0.5, 2.5, 5.0, 10.0, 15.0 and 100 mol% Zn2+) were produced by precipitation method and using calcium nitrate converted from eggshell residues. These materials were carefully designed to be used in bone regeneration, and the results demonstrated essential properties to improve the bone repair processes, such as nanometric size, spherical and/or spherocylindrical morphology, negative zeta potential, antioxidant action and ability to scavenger reactive oxygen species (ROS). In addition, antimicrobial tests demonstrated that the modification of HAp with zinc ions induced a photomodulated antibacterial action on HAp, since all tested composites containing zinc exhibited an inhibitory effect against Staphylococcus aureus (S. aureus) bacteria, which was expressively intensified after irradiation with visible light. This photomodulated antibacterial action is essentially interesting to prevent the occurrence of post-surgical infections common in placement of bone implants. Among these materials, HAp-Zn 15.0% is noteworthy, since it presented the lowest minimum inhibitory concentration (MIC) of 0.12 mg mL−1 in the absence of light, and 0.06 mg mL−1 after 3 h of exposure to the visible light. In this context, our new findings showed that the antibacterial activity of these photoactive composites against S. aureus is not attributed only to the leaching of zinc ions, but also to action of •OH and O2•− radicals, which can be generated even in the absence of irradiation. Additionally, our multifunctional composites were able of inhibit S. aureus bacteria and concomitantly stimulate the growth of pre-osteoblastic cells, ensuring its efficient use in regenerative medicine.

Studies on the Upper Leaf Necrosis in Orientalliliums

Oriental Lilium is one of the commercial bulbous flower crops grown for its cut flower and ornamental value. Upper leaf necrosis is a nutrition disorder that is specific to certain conditions and often misconceived with other disorders. The symptoms of upper leaf necrosis occur on the growing portions of the upper 3 to 5 pairs of young leaves in oriental lilium and it is more specific. The imbalance of calcium and boron nutrients which is actively involved in the growing regions of plants viz., root tip, bud development, and in the meristematic tissues resulting in deficiency causes upper leaf necrosis in the Oriental lilium. The research on supplementing the deficiency of nutrients through foliar application during the vegetative phase on critical days in oriental lilium variety Paradero helped in alleviating the necrosis symptoms. Treatments withfoliar application of 0.08% &amp; 0.1% each of calcium nitrate &amp; borax applied from 30 to 45 days after planting at 5 days intervals resulted in no visible necrosis symptoms (score 0), early appearance of flower bud (48 days) and a greater number of flower buds (3 - 4). Treatment with foliar application of 0.1% each of calcium nitrate &amp; borax ensures a greater number of flower buds (4) per plant.

Microscopic deposition-property relationships in microbial-induced consolidation of coal dusts

In recent years, the preparation of new microbial dust suppressants based on microbial induced carbonate precipitation (MICP) technology through enriched urease-producing microbial communities has become a new topic in the field of coal dust control. The deposition of CaCO3 was the key to suppress coal dust. However, deposition characteristics in the field is not sufficient and the relationship between deposition characteristics and erosion resistance is not clear, which hinders the development of engineering application of new microbial dust suppressant. Therefore, based on X-CT technology, this paper observed and quantified micro-deposition of bio-consolidated coal dust with different calcium sources. Furthermore, a conceptual framework for deposition was proposed and its correlation with erosion resistance was revealed. The results showed that CaCO3 induced by calcium chloride and calcium lactate was aggregate deposited. Aggregate deposited CaCO3 was small in volume, showed the distribution of aggregation in the central area and loose outside, and mosaiced pores. CaCO3 induced by calcium nitrate was surface deposition due to attached biomass. Surface deposition was mostly large volume CaCO3 expanding from the inside out, which could cover coal dust to a high degree and completely cemented pores. In addition, the threshold detachment velocity of coal dust cemented by surface deposition was increased by 17.6–19.1% compared to aggregate deposition. This depended on the abundance and strength of CaCO3 bonding between coal dust particles under different deposition. The two-factor model based on porosity and CaCO3 coverage can well express relationship between erosion resistance and depositional characteristics. Those results will help the engineering application of MICP technology in coal dust suppression.

AgNPs incorporated in Eu(III)-doped hydroxyapatite biomaterial: Spectroscopic, cytotoxicity, and antimicrobial investigation

This study aimed to synthesize and to characterize hydroxyapatite with antimicrobial action. For the synthesis, the precursors calcium nitrate and phosphoric acid were employed; europium(III), 1 % w/w in relation to calcium(II), was used as spectroscopic probe, to investigate structural alterations. Silver nanoparticles, as antimicrobial agents, were added to the resulting material. Formation of the hydroxyapatite phase was confirmed by X-ray diffraction and vibrational spectroscopy in the infrared region. Incorporation of silver nanoparticles in the material was confirmed by electronic absorption spectroscopy in the ultraviolet–visible region, through the absorption band at approximately 400 nm. Scanning electron microscopy revealed that the material had adequate morphology to induce bone formation. The excitation, emission, and lifetime measurements of the structural probe, europium(III), showed that the hydroxyapatite unit cell had two symmetry sites. Cytotoxicity evaluation in human cells showed that the material was toxic at concentrations above 1250 μg/mL. At 2000 ppm, the material displayed antimicrobial activity against E. coli, but the maximum evaluated concentration was insufficient to verify activity against S. aureus. Therefore, hydroxyapatite bearing silver nanoparticles is a promising material for application in the medical area.

Analysis of sorption/desorption of cadmium and lead in the legal amazon soils

Sorption and desorption tests were carried out for competitive and non-competitive systems with isotherms to verify the presence of Cd and Pb in soils. The soils investigated were: (i) with natural content of organic matter and (ii) with residual content of organic matter. Hydrated nitrate salts of Cd and Pb diluted in 0.01 M calcium nitrate solution in six concentrations were used for the Cd solutions and, for the solutions of Pb, five concentrations. For multielement solutions, mixtures of the simple Cd and Pb solutions in a 1:1 ratio were used. The results of the first stage tests (i) showed good adjustments of the experimental data to the isotherms of Langmuir, Freundlich and Linear, which did not occur for the tests in stage (ii). According to the tests (i), the organic matter was the soil attribute of dominant influence in the sorting mechanisms. The parameters Qo and Kd were adequate to evaluate the adsorption of the studied metals, especially Cd. In step (ii), there was a significant increase in metal retention, especially for element Pb in the samples of Haplic Cambisol (AM) and Red-Yellow Latosol1 (RO), justified by the combined action of (1) increasing the surface area of the mineral fraction, previously covered by organic matter; and (2) increase in soil pH. The Cd element was more bioavailable in relation to the Pb. This was confirmed by the high desorption values observed for Cd. The samples of Haplic Cambisol and Red-Yellow Latosol demonstrated greater capacity to retain Cd and Pb.