Medium Concentration Research Articles

Optimizing Different Medium Component Concentration and Temperature Stress Pretreatment for Gynogenesis Induction in Unpollinated Ovule Culture of Sugar Beet (Beta vulgaris L.)

The great economic importance of sugar beet determines the ongoing biotechnological studies conducted worldwide to improve the technology of obtaining doubled haploids (DHs) using the method of unpollinated ovule culture in vitro. To improve the induction of gynogenesis, we tested the effect of thidiazuron (TDZ), temperature bud pretreatment, different concentrations of sucrose, and culturing on liquid or solid medium. Three genotypes were tested in this study. The use of TDZ at a concentration of 0.4 mg/L in solid IMB (induction medium for Beta vulgaris) induction nutrient medium with 3 g/L phytagel, 50 g/L sucrose, 200 mg/L ampicillin and cultivation at 28◦C in the dark produced up to 16.7% induced ovules. The liquid nutrient medium of the same composition induced up to 8% ovules. Increasing TDZ concentration to 0.8 mg/L resulted in reduction or total inhibition of gynogenesis, depending on the genotype. Reducing the sucrose concentration to 20 g/L or increasing it to 80 g/L was not effective. In all three genotypes, the absence of temperature pretreatment of buds (5–6 °C) showed the best results. The plant regeneration with MS nutrient medium of 20 g/L sucrose, 3 g/L phytagel, 1 mg/L 6-benzylaminopurine (BAP) and 0.1 mg/L gibberellic acid (GA3) resulted in up to seven shoots from one induced ovule in the most responsive genotype. We showed by flow cytometry, chromosome counting and chloroplast number assessment that all regenerant plants were haploid (2n = x = 9).

Insight into three water additives: Revealing the protective effects on survival and stress response under cold stress for Pacific white shrimp Litopenaeus vannamei.

The reproduction, development and growth of shrimp were hindered by cold stress, and even death was caused in severe cases. Moreover, huge economic losses to the shrimp aquaculture industry were caused every year by cold currents. The purpose of this study was to investigate the potential protective effects of water additives on the cold stress resistance of Pacific white shrimp (Litopenaeus vannamei) and their ability to improve the survival and stress response of the shrimp. Three potential cold-resistant additives adenosine triphosphate (A), soybean phospholipid (SP) and Clostridium butyricum (CB) on Pacific white shrimp under cold stress were added to the water with three concentrations for each additive. The mortality, activities of antioxidation enzymes and expression of anti-stress related genes in each group under cold stress were detected. The results showed that the cumulative mortality of low concentration for adenosine triphosphate (AL) and soybean phospholipid (SPL), medium concentration for soybean phospholipid (SPM) and high concentration for Clostridium butyricum (CBH) groups were significantly lower than that of the control (C) group when temperature maintained at 13°C for 6 days. Total antioxidant capacity (T-AOC) content in shrimp plasma was significantly higher, while malondialdehyde (MDA) content was significantly lower than that in the C group. Gene expression analysis showed that 0.4mg/L of adenosine triphosphate could regulate the immune defense ability and decrease apoptosis level of Pacific white shrimp under cold stress. Soybean phospholipid (2mg/L) could enhance the immune ability of hepatopancreas, and Clostridium butyricum (10mg/L) could significantly increase the expression of stress-related genes in shrimp intestine. Overall, these findings suggested that adenosine triphosphate and soybean phospholipid have the potential to be used as cold-resistant additives in Pacific white shrimp culture. This study provided valuable insights into addressing the problem of cold stress in shrimp culture.

Prediction of CO pollutant in Mashhad metropolis, Iran: Using multiple linear regression

AbstractGiven the importance of carbon monoxide (CO) in acute health threats, studies have been conducted in different countries and cities (272 cities in China and 337 cities on a global scale) on the relationship between daily mortality and CO while the spatial analysis of factors affecting CO pollutant in cities, especially in developing countries, has rarely been done. Accordingly, this research has measured the effect of five environmental‐social variables (ESVs) on the spatial distribution of CO pollutants in the metropolis of Mashhad, Iran. CO concentration data were collected in 23 air pollutant monitoring stations in an area of 356 km2 in 2019. Then, the relationship between five variables and CO pollutant were measured using linear and multiple regression by Sentinel 2A and 3 satellite images in ArcGIS and TerrSet software. The results show that the mean CO concentration averages at 1.56 ppm in the whole city. But its range varies between 0.171 and 2.907 ppm, which is a low figure compared with presented standards and does not indicate a critical situation. The results of multiple regression indicate that 42% of the variance in CO concentration is explained by independent variables. Among five independent variables, the beta value of the land surface temperature (LST) and digital elevation model (DEM) variables is negative and positive for the other three variables, including population density, normalised difference vegetation index (NDVI) and normalised difference built‐up index (NDBI). It should be noted that the strongest correlating variable is population density. Prediction of the spatial distribution of CO pollutants shows the division of the city into three areas: (1) the south and southwest slopes of the city with a low concentration; (2) central areas with a medium concentration; and (3) northern and northeastern areas of the city with a high concentration where low‐income groups reside and there are more worn‐out vehicles, motorcycles and industrial workshops. Areas with high CO concentration need more attention from urban managers.

Failure analysis on abnormal damage and corrosion of methanol distillation column in MTBE production plant

Methyl tert-butyl ether (MTBE) is a commonly used gasoline additive that improves combustion and reduces pollutant emissions. The methanol distillation column is an integral part of the recovery system in MTBE production plants, used to separate and recycle unreacted methanol from water through distillation. During regular maintenance, severe damage to the support ring and abnormal perforations in the column were discovered. Despite repair welding, the column still leaked. Various investigations were conducted to determine the root cause of the failure. The chemical composition, metallurgical structure, and hardness of the support ring and column materials were examined, and the medium in the column was characterized. The medium at the bottom of the column was unexpectedly subjected to an undesirable excessive acidity (with a pH of approximately 3.8) dominated by the upstream etherification reaction deacidification, and provided common basic conditions for localized pitting and uniform corrosion of low carbon steel. What's more, the appearance of clean and smooth corrosion pits and scour traces on the perforated column wall, as well as honeycomb pits and arc-shaped layered traces on the support ring, revealed that the corrosion failure was intensified due to the interaction of selective erosive corrosion and medium concentration accelerated corrosion caused by multiple corrosion types of the acidic medium. In addition, the unpolished surface from incomplete repair welding was another significant factor. Based on these findings, specific countermeasures were implemented and proved effective.

Nano engineered synthesis layer by layer and transparent synergistic antimicrobial coating based on Se/Ag/TiO2/ZnO hybrid nanostructures

Bio Threat Storm will payed popular attention to bio safety. Increasing of bio safety was depend on decreasing of microorganism concentration on surface and air. Focal point of bio safety is improving of anti-microbial activity of anti-microbial agent and anti-microbial surface. Anti-microbial nanomaterial such as titanium dioxide (TiO2) and Zinc oxide (ZnO) can be used for fighting to pathogen and decrease of microorganism amount. According to some report pathogen for example COV 19 type 2 can be transfer by surface. So far decrease of viruses concentration surface have important object in control of viruses pandemic. According to this object, we designed and synthesized synergistic antimicrobial coating agent based on photo catalytic activity of titanium oxide nanoparticles, ZnO nanoparticles, Selenium and silver nanoparticle was added to enhance antimicrobial activity. These metal and metal oxide Nano particle dispersed in water and mixed by organic resin. Antibacterial, antifungal and antiviral activity of coating studied after coating procedure on polymeric surface. The goal of this work is to evaluate the effects of antimicrobial coating activity against two common bacterial strains, including E. coli and Staphylococcus aureus. Antibacterial study showed after interaction of positive and negative gram bacteria to coated surface after 24 hours the number of viable bacteria was decreased to 2.4×106 and 2.3×106 (CFU/ml) respectively. Antiviral activity of coating layer was also performed against Enterovirus type D68 which showed it could be inactivated viruses in low and medium concentration. Results of this research showed that Nano engineered synthesis layer by layer and transparent antimicrobial coating can be used to overcome the emerging pandemic.

Commutability evaluation of candidate reference materials and ERM-DA470k/IFCC for immunoglobulin M using two international approaches.

This study aimed to assess the commutability of frozen pooled human serum (PHS), high concentration of Immunoglobulin M (IgM) pure diluted materials (HPDM), commercialized pure materials (CPM), and dilutions of ERM-DA470k/IFCC in IgM detection using the CLSI and IFCC approaches, to support standardization or harmonization of IgM measurement. Twenty-four serum samples, relevant reference materials (PHS, HPDM, CPM), and different ERM-DA470k/IFCC dilutions were analyzed in triplicate using six routine methods. The commutability of the relevant reference materials was carried out following CLSI EP30-A and IFCC bias analysis. According to the CLSI approach, low, medium, and high concentrations of PHS, HPDM, and CPM were commutable on 10, 13, 15, 13, and 8 of 15 assay combinations, respectively. Using the IFCC approach, low, medium, and high concentrations of PHS, HPDM, and CPM were commutable on 10, 11, 9, 15, and 10 of 15 assay combinations, respectively. The ERM-DA470k/IFCC dilutions with D-PBS and RPMI-1640 Medium were commutable on 13 of 15 assay combinations according to CLSI and were commutable on all 15 assay combinations using IFCC approach. High concentration of PHS were commutable on all six detection systems using the CLSI approach. Low and medium concentration of PHS showed unsatisfied commutability. HPDM, not CPM have good commutability, has the potential to become reference materials. ERM-DA470k/IFCC diluted with different medium showed different commutability.

Influence of polymer solution concentration and media permeability on the residual resistance factor

Purpose. Determination of the required concentration of polymer solution, providing the maximum well insulation effect, depending on the filtration characteristics of the medium. Methodology. The research was conducted by experimental method using the methodology of planning the experiment. The theory of rational planning was used by varying two variables on five levels. Media permeability and polymer solution concentration were used as variables. Methods of mathematical statistics were used in processing the results. Findings. Experimental studies made it possible to build a model expressing the dependence of the residual resistance factor on the permeability of the medium and the concentration of the polymer solution. By further statistical processing the connection between permeability and necessary concentration of polymer solution was obtained. Originality. The experimental studies have substantiated the possibility of evaluating the influence of medium permeability and concentration of polymer solution on the residual resistance factor and determined its dependence on the concentration of polymer solution and medium permeability. The main point of polymer solutions application is justification and choice of the reagent concentration. The concentration should be selected in such a way that it provides the maximum value of the residual resistance factor and the viscosity of the solution necessary to level out permeability heterogeneity of the environment to some extent. To achieve this, a relationship has been obtained that allows determining the concentration of the polymer solution at a given permeability of the environment that provides the maximum residual resistance factor. Practical value. The conducted experimental studies allow developing the ideas about the regularities of water manifestations. The results of the research allow selecting purposefully both the formulations of composite systems and the technology of their application to improve the efficiency of oil production and to limit water inflows in specific geological and physical conditions.

Long-term exposure to aryl hydrocarbon receptor agonist neburon induces reproductive toxicity in male zebrafish (Danio rerio)

Neburon is a phenylurea herbicide that is widely used worldwide, but its toxicity is poorly studied. In our previous study, we found that neburon has strong aryl hydrocarbon receptor (AhR) agonist activity, but whether it causes reproductive toxicity is not clear. In the present study, zebrafish were conducted as a model organism to evaluate whether environmental concentrations of neburon (0.1, 1 and 10 µg/L) induce reproductive disorder in males. After exposure to neburon for 150 days from embryo to adult, that the average spawning egg number in high concentration group was 106.40, which was significantly lower than 193.00 in control group. This result was mainly due to the abnormal male reproductive behavior caused by abnormal transcription of genes associated with reproductive behavior in the brain, such as secretogranin-2a. The proportions of spermatozoa in the medium and high concentration groups were 82.40% and 83.84%, respectively, which were significantly lower than 89.45% in control group. This result was mainly caused by hormonal disturbances and an increased proportion of apoptotic cells. The hormonal disruption was due to the significant changes in the transcription levels of key genes in the hypothalamus-pituitary-gonadal axis following neburon treatment. Neburon treatment also significantly activated the AhR signaling pathway, causing oxidative stress damage and eventually leading to a significant increase in apoptosis in the exposed group. Together, these data filled the currently more vacant profile of neburon toxicity and might provide information to assess the ecotoxicity of neburon on male reproduction at environmentally relevant concentrations.

Different Concentrations of Chemical Topping Agents Affect Cotton Yield and Quality by Regulating Plant Architecture

Manual removal of the main stem tips of cotton (Gossypium hirsutum L.) is a traditional topping approach in China. However, chemical topping has become an inevitable trend. Therefore, it is of great significance to study the effect and appropriate concentration of agents for advancement of cotton whole process mechanization management technology. A two-year field experiment was conducted to evaluate the effects of different methods of topping on cotton yield and plant architecture in Shihezi, Xinjiang, China. Plant topping included manual topping, non-topping as the control, and chemical topping (high, medium, and low concentrations of topping agent) to determine a suitable topping method and topping agent concentration for machine-picked cotton. Chemical topping was performed using fortified mepiquat chloride (DPC+). Chemical topping and manual topping increased seed cotton yield compared with non-topping. Compared with non-topping, high, medium, and low concentrations of topping agent significantly increased the yield by 19.5–27.9%, 24.1–29.4%, and 24.3–28.4%, respectively. Topping treatment mainly regulated yield and total boll number per unit area by affecting the boll number per plant and had a certain positive effect on fiber strength but no significant effect on boll weight. Chemical topping affected both vertical and horizontal plant architecture characteristics of cotton; the plant height of low-, medium-, and high-concentration treatments increased by 7.2–11.4 cm, 4.0–5.7 cm, and 2.3–4.4 cm, respectively, compared with manual topping and decreased by 5.1–7.8 cm, 8.3–13.5 cm, and 9.4–16.9 cm, respectively, compared with non-topping. The number of main stem internodes was significantly different between high- and low-concentration treatments, which showed that the higher the concentration, the lower the number of the main stem internodes. Chemical topping controlled the increase in the length of the upper branches, the higher the concentration, the lower the increase in the length of the upper fruit branch. Compared with non-topping, the medium concentration of topping agent controlled the number of fruit branches, similar to manual topping. The role of upper internode length of cotton cannot be ignored under chemical topping. The peak leaf area index (LAI) of medium- and high-concentration treatments was delayed for 1 week in the late growth period (after topping for 28 d) compared with manual topping. The LAI values were high, and the duration of high values was prolonged. The optimal chemical topping agent was the medium concentration.

Regulation of colony-stimulating factor 1 receptor inhibitor pexidartinib on the senescence of mouse bone marrow-derived macrophages stimulated by lipopolysaccharide

Objective: To investigate the effects of colony-stimulating factor 1 receptor (CSF-1R) inhibitor pexidartinib (PLX3397) on the senescence of bone marrow-derived macrophages (BMDM) stimulated by lipopolysaccharide (LPS). Methods: BMDM were isolated and cultured from femurs and tibiae of 10 male C57BL/6 mice aged 6-8 weeks (obtained from Laboratory Animal Center of Guizhou Medical University). They were divided into blank control group, LPS group (treated with 1 μg/ml LPS for 24 h) as well as low, medium and high concentration PLX3397 pretreatment groups (treated with 100, 500 and 1 000 nmol/L PLX3397 for 4 h respectively followed by 1 μg/ml LPS for 24 h). The corresponding markers of macrophages were detected by flow cytometry. Cell viability was detected by cell counting kit-8 and cellular senescence was detected by senescence-associated-β-galactosidase (SA-β-gal) staining. Meanwhile, protein expressions of cycle-dependent kinase inhibitor p16, p21 and CSF-1R were detected by Western blotting, and the expressions of p16 and p21 were detected by intracellular immunofluorescence. Real-time fluorescence quantitative PCR (RT-qPCR) was used to investigate the mRNA levels of senescence-associated secretory phenotype (SASP) genes including interleukin (IL), IL-1β, chemokine-1/10 (CXCL-1/10), matrix metalloproteinase-8 (MMP-8), and transforming growth factor-β (TGF-β). Results: The rate of SA-β-gal positive staining in medium and high concentration PLX3397 pretreatment groups [(39.33±4.93)% and (36.33±3.06)% respectively] were significantly downregulated compared with LPS group [(52.00±3.00)%] (P=0.020, P=0.005). The expression of CSF-1R protein in low, medium and high concentration PLX3397 pretreatment groups were (0.74±0.18, 0.61±0.07, 0.54±0.06), all of which were significantly lower than that in LPS group (1.16±0.08) (P=0.013, P=0.002, P<0.001). The expression levels of CSF-1R mRNA in low, medium and high concentration PLX3397 pretreatment groups (1.04±0.06, 0.90±0.05, 1.18±0.08) showed similar trend (2.90±0.25) (P<0.001). The average fluorescence intensity of p16 in all PLX3397 pretreatment groups were 49.76±3.65, 48.21±1.72, 47.99±1.26 respectively, which were significantly lower than that in LPS group (66.88±5.85) (P=0.001, P<0.001, P<0.001). The average fluorescence intensity of p21 in medium and high concentration PLX3397 pretreatment groups were (34.43±3.62, 30.13±0.86), significantly lower than that in LPS group (46.82±5.33) (P=0.043, P=0.007). The expression of p16 protein in low, medium and high concentration PLX3397 pretreatment groups (0.56±0.04, 0.55±0.04, 0.35±0.19) were significantly lower than that in LPS group (0.98±0.10) (P=0.003, P=0.002, P<0.001), as well the expression of p21 protein (0.69±0.20, 0.42±0.08, 0.26±0.14) (P=0.032, P=0.002, P<0.001). According to the results of RT-qPCR, the expressions of IL-6, IL-1β, CXCL-1, CXCL-10 and MMP-8 in PLX3397 pretreatment groups were significantly lower than those in LPS group (P<0.001), while the expression of TGF-β increased (P<0.001). Conclusions: LPS could induce the cell senescence, increase the secretion of SASP and aggravate local inflammation by activating the CSF-1R on the cell surface of bone marrow-derived macrophages. CSF-1R inhibitor PLX3397 might attenuate CSF-1R activation associated with LPS and inhibit the senescence of bone marrow-derived macrophages induced by LPS.

Two-step fabrication of cellulose embedded Fe3O4/Fe3+ composite beads as catalyst in degradation of sulfamethoxazole in floating bed reactor

In this study, magnetite particles were successfully embedded in sodium carboxymethyl cellulose as beads using FeCl3 as the cross-linker in two step-method and it was used as a Fenton-like catalyst to degrade sulfamethoxazole in aqueous solution. The surface morphology and functional groups influence of the Na-CMC magnetic beads was studied using FTIR and SEM analysis. The nature of synthesized iron oxide particles was confirmed as magnetite using XRD diffraction. The structural arrangement of Fe3+ and iron oxide particles with CMC polymer was discussed. The influential factors for SMX degradation efficiency were investigated including the pH of the reaction medium (4.0), catalyst dosage (0.2 g L−1) and initial SMX concentration (30 mg L−1). The results showed that under optimal conditions 81.89% SMX degraded in 40 min using H2O2. The reduction in COD was estimated to be 81.2%. SMX degradation was initiated neither by the cleaving of C–S nor C–N followed by some chemical reactions. Complete mineralization of SMX was not achieved which could be due to an insufficient amount of Fe particles in CMC matrix that are responsible for the generation of *OH radicals. It was explored that degradation followed first order kinetics. Fabricated beads were successfully applied in a floating bed column in which the beads were allowed to float in sewage water spiked with SMX for 40 min. A total reduction of 79% of COD was achieved in treating sewage water. The beads could be used 2–3 times with significant reduction in catalytic activity. It was found that the degradation efficiency was attributed to a stable structure, textural property, active sites and *OH radicals.

Validation of Free Formaldehyde Determination Method in DT Vaccine and Tetanus Toxoid Antigen.

Validation is a Good Manufacturing Practice principle that proves any procedure, process, method, equipment, material, activity, or system actually leads to the expected results. This study validates the method for the determination of free formaldehyde in biological products (including the diphtheria-tetanus vaccine and tetanus toxoid antigen). The operatingprocedure of this method is based on pharmacopoeial monographs. It also does not require full validation, although its suitability under the actual condition of use should be verified. Performance characterizations, such as accuracy, intra-precision (repeatability), intermediate precision (inter-precision), linearity, range, and the limit of quantitation, were investigated and calculated. Accuracy and precision were studied at different concentration levels by spiking known amounts of formaldehyde in real samples. The accuracy and precision results were expressed as the recovery and the relative standard deviation (RSD), respectively. Precision was expressed as intra-precision (repeatability) and inter-precision. Intra-precision or repeatability was performed by one operator in one day by adding three levels of concentration to the products. The inter-precision was conducted by one operator in three individual days within the same laboratory at three concentration levels. Range and linearity were assessed by investigating the correlation coefficient of the regression line between different concentrations of formaldehyde and their response. The acceptance criteria and limits were defined for these validation parameters in these biological products. The RSD for intra-day and inter-day precision studies was less than 5% in a medium concentration of linear range. At this concentration level, accuracy was 90%-110%. The method's linearity ranged between 0.0000039%-0.01% w/v of formaldehyde with a correlation coefficient of 0.9999. The results exhibited sufficient linearity, accuracy, precision, and range. Therefore, this method can be used successfully to determine free formaldehyde for biological products.

EFFECT OF LARVAL DENSITY AND DIET ON THE GROWTH AND SURVIVAL OF Perna perna MUSSELS IN RECIRCULATION SYSTEM (RAS).

This study evaluated the effect of initial larval stocking density and microalgae concentration in the diet on the growth and the number of competent larvae (number of live larvae at the end of the experiment retained on a sieve with mesh size of 210 µm) of Perna perna in a water recirculation system (RAS). The experiment was conducted using a completely randomized design and factorial scheme, with one factor being the food concentration at three levels (low: between 1.26 to 2.19, medium: between 2.36 to 3.94 and high: 5.03 to 7.29 x 104 cells mL⁻¹) and the second factor being the larval culture density, also at three levels (20, 80 and 200 larvae mL⁻¹), with 3 replications in each treatment. Larvae fed with the diet with low and high concentrations did not reach competence (210 µm) in 16 days. However, for larvae fed with the medium concentration (2.36 to 3.94 x 104 cells mL⁻¹), the average percentage of competent larvae, on day 16, was 21.8% ± 7.45, 27.4% ± 9.91 and 0.80% ± 0.26 at the densities 20, 80 and 200 larvae mL-1, respectively.

Impact of Combined Exposure to Glyphosate and Diquat on Microbial Community Structure and Diversity in Lateritic Paddy Soil

Microbial communities play crucial roles in the biogeochemical cycling of many important soil elements. Pesticides are known to affect non-targeted soil microorganisms. Glyphosate (GP) and diquat (DQ), two commonly used non-selective herbicides, often co-exist in lateritic paddy soil rich in iron/aluminum oxides. However, there is limited information on their co-impact on microbial community structure and diversity in this type of soil. Here, the short-term effects of combined exposure to GP and DQ on microbial diversity and community structure shifts were investigated in lateritic paddy soil from a tropical agricultural region (Hainan, China). The combined utilization dosages of two herbicides were set in three concentrations: low concentration (1 fold of the recommended dosage), medium concentration (10 fold of the recommended dosage) and high concentration (100 fold of the recommended dosage). The structure and diversity of microbial communities were determined via 16S rRNA and ITS gene high-throughput sequencing. The results revealed that Actinobacteria and Proteobacteria were the most sensitive microbial phyla to the combined exposure of GP and DQ in lateritic paddy soil. The combined exposure to GP and DQ increased the abundance of Actinobacteria but significantly inhibited that of Proteobacteria, especially at low and medium concentrations. Compared with CK, mixed herbicide (GP + DQ) had no adverse effects on the richness of bacteria and fungi communities as well as on the diversity of bacteria communities, but it significantly decreased the diversity of fungi communities at high concentrations within 28 days. However, the effects of combined exposure to GP and DQ on soil microbial richness and diversity were not significantly different from those of separate exposure of the two herbicides. In conclusion, the combined application of GP and DQ had no more adverse effects on soil microorganisms. Therefore, these two herbicides can be used reasonably in actual agricultural production.

Pit-mound microrelief on a forested slope drives infiltration and preferential flow after heavy rainfall – experiments with soil resistance monitoring and dye tracing

With the changing climate, short heavy rainfalls (SHRs) are becoming more frequent and intensive. The distribution of rainwater and subsurface runoff formation in forest soils can be strongly affected by soil disturbances and surface microrelief. Rainwater redistribution and the formation of preferential flow in response to natural and simulated SHRs were investigated in soil profiles on slopes forested by Norway spruce with a pit-mound microrelief formed by historical tree uprooting using two independent methods; soil electrical resistance monitoring and the application of dye tracer. In the deepest soil layers, resistance decreased in responses to natural SHRs on average by 46% in pits and by 11% on ‘smooth slope’ controls, reflecting the deeper redistribution of infiltrated water in pits. Dye tracing in the simulated rainfall revealed the formation of shallow biomat flow at the control plot. In contrast, the shallow lateral flow was focused by the pit and redirected into funnel flow underneath the pit bottom. The sum of medium and high dye concentration classes obtained with the support vector machine classification of profile photographs indicated a higher water entry into topsoil and subsoil layers in pit (44% and 31% of area, respectively) as compared to the control profile (16% and 8% of area, respectively). Leaving pit-mound microrelief as the natural legacy in forest soils can mitigate some of the negative hydrological effects of intensive forest management and may improve the water yields on forested slopes by redirecting shallow subsurface runoff and facilitating deep distribution of infiltrated water. Such beneficial effects of pit-mounds on the hydrology of forested slopes should be considered in future hydrological modelling and land management.

Coupling fluorescent probes to characterize S-containing compounds in a sulfate reducing bacteria involved in Hg methylation

The microbial methylation of inorganic mercury Hg(II) is governed by S-containing compounds such as thiols (RSH) and sulfides (S2−). Various S-containing molecules in an environmental or culture medium can be difficult to assess because of the complexity of the medium, poor stability, and low concentration ranges of sulfide and thiol compounds. Here, we applied two fluorescence spectroscopy-based methods using α, β-unsaturated ethanoylcoumarin fluorophore (DHC) for the quantification of sulfides, and monobromo (trimethylammonio) bimane (qBBr) to quantify total thiol concentrations (in extracellular and bacterial cell fractions). The potential interferences of both organic and inorganic compounds from the matrix were evaluated. In the presence of Hg species, both methods allowed the quantification of free sulfides or thiols (not forming complexes with Hg). The two methods were highly sensitive, with detection limits of 100 nM and 20 nM for thiols and sulfides, respectively. They also exhibited high selectivity for the detection of thiols or sulfides against other tested matrix compounds. Finally, both methods were applied to characterize S-containing compounds in a culture of Pseudodesulfovibrio hydrargyri strain BerOc1, a methylating sulfate-reducing bacterium (SRB) exposed to 0.1 mM of cysteine. During bacterial growth, we used (i) DHC probe to quantify sulfide concentration in the bulk fraction, (ii) qBBr for total extracellular thiols and total thiols adsorbed on the cells, and (iii) liquid chromatography-tandem mass spectrometry to track cysteine degradation and characterize other thiols. The time series until the end of BerOc1 growth showed biodegradation of cysteine, and biosynthesis of sulfides and other thiol compounds.

Application of Quality by Design Approach in the Optimization and Development of the UPLC Analytical Method for Determination of Fusidic Acid in Pharmaceutical Products

Background: Analytical techniques are a crucial method used in quality control procedures. Fusidic acid (FU), an antibacterial drug, is available on the market in a semisolid dosage form. This work aimed to develop a simple, sensitive, and robust UPLC assay for FU. Method: The effect of the formic acid concentration (X1 (1%, 0.55%, and 0.1%)), and column temperature (X2 (40, 32.5, and 25 °C)) on the retention time, peak area, and peak height were determined. Results: The results show that a long retention time of 1.18 min can be achieved with a low column temperature and a low to medium concentration of formic acid. A good peak height resolution was obtained with a low concentration of formic acid at different temperature settings. The optimized condition was suggested by the software program to analyze the drug in a mobile phase, consisting of 72% acetonitrile and 28% water containing 0.1% formic acid with a column temperature adjusted to 40 °C. Conclusion: The method was validated in terms of linearity, accuracy, precision, and robustness. In addition, the stability degradation study determined that the method can separate the drug from other degradation production. The method was applicable to determine the drug content in the marketed product.

Synthesis of Ni-Fe-CO3 layered double hydroxide as Effective Adsorbent to remove Cr(VI) and ARS-dye from aqueous media

Ni2+/Fe3＋LDH, (Ni-Fe-CO3 LDH) with Ni/Fe molar ratio 3.0 was synthesized by co-precipitation for the remediation of chromium (VI), and Alizarine Red-S (ARS-dye) as anionic species. The investigated adsorbent was characterized by TGA, SEM, XRD, BET and FTIR. The effect of the hydrogen ion concentration of the medium, shaking time, ARS-dye and/or Cr(VI) concentration and adsorbents mass on the process was studied. The results of Ni-Fe-CO3 LDH fitted well with the pseudo-second-order model. Langmuir isotherm is more favor than the Freundlich isotherm with maximum capacity (Qmax) of 69.9 and 6.1 mg/g for ARS-dye and Cr(VI), respectively.

Foliar spraying of potassium gluconate promotes the synthesis of the seed oil of Styrax tonkinensis

AbstractStyrax tonkinensis is a promising woody biodiesel species. In this experiment, we investigated how foliar spraying of potassium gluconate solution affected the production of seed oil in S. tonkinensis. Leaf spraying of potassium gluconate solution appreciably promoted the photosynthesis of S. tonkinensis leaves through both the light reaction and the dark reaction. By boosting the activity of enzymes involved in glucose metabolism and seed oil synthesis, foliar spraying of potassium gluconate solution also dramatically enhanced glucose metabolism and seed oil synthesis in the S. tonkinensis seeds. This indicates that foliar spraying with potassium gluconate solution discernibly improved the synthesis of seed oil in S. tonkinensis by encouraging the transit of photosynthetic products from the source to the reservoir and the flow of carbon into the seed oil synthesis in the seeds. Overall, the medium concentration of potassium gluconate solution (4 g/L) was found to be the most effective for increasing the oil content of S. tonkinensis seeds. While higher potassium gluconate solution concentrations (6 g/L) had a slight inhibitory effect on specific indicators (ACCase) during specific seed development periods. This study highlighted the importance of potassium for seed oil synthesis in woody plants and provided a useful foundation for future cultivation practices aimed at enhancing seed oil synthesis in woody plants.

Research on highly sensitive quantitative detection of aflatoxin B2 solution based on THz metamaterial enhancement

Food such as cereal crops, oil crops and dairy products are very easy to produce highly toxic and carcinogenic aflatoxins during inappropriate storage. Therefore, it is of great significance to achieve rapid, non-destructive and highly sensitive detection of aflatoxin. A terahertz metamaterial sensor with “X” compound double-peak structure is designed based on electromagnetic theory to realize highly sensitive detection of aflatoxin B2 solution. It is found that the amplitude of the transmission peak of the terahertz transmission spectrum of aflatoxin B2 (AFB2) solution around 1.2 THz and 2.0 THz gradually decreased with the increase of the concentration of aflatoxin B2 solution, and the frequency of the transmission peak gradually shifted to high frequency with the increase of the concentration of aflatoxin B2 solution, hence a full concentration model was established. And a strategy of first classifying concentration intervals and then building a grouped quantitative model was proposed. The Limit of Detection (LOD) of the interval sub-model of low and medium concentration of aflatoxin B2 solution has been greatly improved with the LOD of the optimal grouping model was 7.28 × 10−11 mg/ml, 4.19 × 10−9 mg/ml and 1.22 × 10−7 mg/ml, respectively. This research verifies the feasibility of terahertz metamaterial sensor based on “X” composite double-peak structure combined with THz-TDS technology for highly sensitive detection of aflatoxin B2 solution. And it provides a new rapid, non-destructive and highly sensitive detection of aflatoxin in food.