Optimum Concentration Range Research Articles

Dimethyl-Sulfoxide-Free Cell Cryoprotectant Derived from Amino Acids.

With the large-scale applications of cryopreservation technology in the cell therapy fields, traditional permeable cryoprotectants (CPAs) have led to serious issues, such as cell cycle arrest, inhibition of cell proliferation and differentiation, apoptosis, altered gene expression, etc. Development of green, non-toxic cryoprotectants is critically needed. Amino acids could serve as substrates for protein and cellular metabolism and as cryoprotectants with non-toxicity, balancing the intracellular water osmotic pressure. Current research on amino acids as cryoprotectants is hindered by several limitations, including unclear protection mechanisms, cryopreservation methods, and poor efficacy of individual formulations. Therefore, three specific amino acids and derivatives, including l-proline, l-carnitine, and betaine, as cryoprotectants were used for two types of cell cryopreservation. Single-factor experiments were conducted to obtain the optimal concentration range for each of the three amino acid cryoprotectants. On the basis of the key thermophysical parameters, the ability to inhibit ice crystals, and the effect after cryopreservation, multivariate orthogonal experiments were carried out to evaluate the actual effect of the three-component mixed cryoprotectant on cell cryopreservation. In comparison to the gold standard of 10% dimethyl sulfoxide (DMSO) for cell cryopreservation, the mixed cryoprotectant derived from amino acids achieves comparable preservation efficacy at lower concentrations with a convenient application method, which offers guidance for DMSO-free cryoprotectants.

Associations between serum mineral concentrations and mortality by renal function in the Ludwigshafen Risk and Cardiovascular Health Study

The association of serum concentrations of minerals and phosphate with overall and cardiovascular mortality based on renal function is poorly understood. 3307 patients (average age 62.7 ± 10.6 years) in the Ludwigshafen Risk and Cardiovascular Health (LURIC) study were grouped by estimated glomerular filtration rate (eGFR) into three categories: < 60, 60–89, and ≥ 90 mL/min per 1.73 m2, per KDIGO 2022 guidelines and were analysed using Cox regression. Low serum sodium and iron concentrations were associated with poor renal function and increased overall mortality risk, whereas higher serum zinc concentrations were associated with reduced overall and cardiovascular mortality risk. Elevated serum copper concentrations were associated with increased mortality risk across all eGFR categories. Comparing low and normal eGFR, we observed a fourfold increase in all-cause mortality risk for eGFR < 60 mL/min per 1.73 m2 and a twofold increase for eGFR 60–89 mL/min per 1.73 m2, accompanied by changes in serum mineral concentrations. The optimal range of mineral and phosphate concentrations in serum was strongly related to renal function. To reduce mortality risk, it’s important to regularly monitor serum mineral and phosphate concentrations as well as renal function, especially in cardiovascular patients with compromised renal function.

Machine Learning Insights into Ascorbic Acid-Enhanced Germination of Black Cumin (Nigella sativa L.) under Cadmium Stress

AbstractThe objective of the present work is to study the impact of seed priming with varying concentrations of ascorbic acid (vitamin C) on the germination process of black cumin (Nigella sativa) under cadmium (Cd) stress. As expected, Cd had a great effect on germination rates and seedling growth. However, the application of ascorbic acid during seed priming effectively alleviated Cd stress and significantly increased seed vigor. Primed seeds exhibited markedly elevated final germination percentage, germination index, mean germination time, seedling length, seedling vigor index, and reduced abnormal seedling percentage. Additionally, vitamin priming reduced membrane lipid peroxidation, in treated seeds. Moreover, seed priming elicited a considerable increase in peroxidase and catalase activity, thus mitigating stress effects and augmenting seed vitality. Our experimental data allowed us to establish 100–150 mg/L as the optimal concentration range for ascorbic acid in seed priming of black cumin. These insights were further corroborated through modeling techniques based on supervised machine learning. Notably, XGBoost emerged as a proficient tool for predicting final germination percentage, mean germination time, seedling vigor index, abnormal seedling percentage, and peroxidase activity, while SVR demonstrated aptitude in forecasting catalase activity and germination index. The Gaussian method exhibited superior performance in predicting malondialdehyde content. These comprehensive findings substantiate the premise that vitamin priming with ascorbic acid serves as a promising strategy to ameliorate germination outcomes under Cd-induced stress conditions.

Influence of alkali molarity on compressive strength of high-strength geopolymer concrete using machine learning techniques based on curing regimes and temperature

The compressive strength behavior of high-strength geopolymer concrete (HSGPC) has been studied in this research work with varying alkali concentration using the novel machine learning techniques. The alkali concentration in the activation solution plays a significant role in the geopolymerization process and affects the resulting compressive strength. In this research work, the range between 4 M and 16 M for alkali molarity (M), 18 kg/m3 and 160 kg/m3 for NaOH and 41 kg/m3 and 229 kg/m3 for NaSi was collected from literature and used in the various design mixes of this exercise. This was necessary because higher alkali concentrations promote a more efficient dissolution and activation of the aluminosilicate compounds, leading to increased geopolymerization and the formation of more calcium silicate hydrate (C-S-H) gel. The increased C-S-H gel content contributes to improved strength development. However, there is an optimal alkali concentration range for the sustainable production of geopolymer concrete, and exceeding this range can have a negative impact on compressive strength and ecofriendly handling of concrete. A total of fifty-three records were collected from literature and deployed in modeling the compressive strength (Fc) considering various curing regimes. Three symbolic machine learning techniques such as genetic programming (GP), evolutionary polynomial regression (EPR), and the artificial neural network (ANN) are used in this research model. The relative importance values for each input parameter were also evaluated, which indicated that all factors have significant impacts on (Fc), but Age (i.e., curing regime) has the most influence compared to FA, NaOH, and CAg then the other inputs. From the model relations between the calculated and predicted values, it can be shown that the decisive model, ANN produced line of parametric equation of y = 0.995x, and produced performance indices; MAE of 2.13 MPa, RMSE of 2.86 MPa and R-squared of 0.981, which makes the ANN the most reliable model in agreement with previous applications of the technique. These are against the poor performance of the EPR and GP, which produced R-squared less than 0.8 with higher error rates. The Taylor chart and the variance distribution, which further compares the accuracy and variances of the developed models support the outcomes. Generally, alkali molarity has shown its potential in the production of HSGPC due to its role in the reactivity phases of the concrete formulation; hydration, activation, pozzolanic, and geopolymerization reactions producing the gel needed for the strength gain in HSGPC.

Effect of Ce co-doping on radiation resistance behavior and laser performance of Er/Yb/Ce co-doped high-phosphorous polarization-maintaining silica fiber

Er/Yb/Ce co-doped high-phosphorus silica fiber core glasses with varying Ce2O3 concentrations were prepared and systematically studied. Based on this research, optimized Er/Yb/Ce co-doped high-phosphorus polarization-maintaining silica fibers were subsequently fabricated using the modified chemical vapor deposition (MCVD) technique and hole drilling method. The study confirmed that there is an optimal range of Ce doping concentrations for spectral performance, Ce doping effectively suppressing the formation of P-related defects during X-ray irradiation, and the dynamic valence state transformation of Ce3+/Ce4+ ions during irradiation enhanced the radiation-resistant properties, as demonstrated through radiation-induced absorption (RIA), electron paramagnetic resonance (EPR), and L3-edge X-ray absorption near edge structure (XANES) spectra. The homemade fiber, with optimized element concentrations, exhibited high laser efficiency comparable to commercial high-power fibers. Furthermore, the radiation-induced background loss of the fiber was 0.16 dB/m under 60 krad γ-rays at a low dose rate of 100 rad/h, and the radiation-induced gain variation (RIGV) was 0.019 dB/krad.

Electrical Doping Regulation of Carrier Recombination Enhances the Perovskite Solar Cell Efficiency beyond 28.

With the power conversion efficiency (PCE) of perovskite solar cells (PSCs) exceeding 26.7%, achieving further enhancements in device performance has become a key research focus. Here, we investigate the impact of electrical doping in the perovskite layer using the drift-diffusion equation-based device physics model, coupled with a self-developed equivalent circuit model. Our results demonstrate that electrical doping can increase the PCE from 24.78% to >28%. In-depth theoretical analysis reveals that these improvements in performance are driven by the modulation of carrier recombination processes through doping, leading to significant increases in the open-circuit voltage and fill factor. Additionally, we explore the influence of physical parameters on device performance. Our study identifies an optimal doping concentration range from 1.0 × 1017 to 1.0 × 1019 cm-3 and a transport layer mobility of >0.01 cm2 V-1 s-1. This work provides a theoretical foundation for the development of ultra-high-performance PSCs through targeted electrical doping strategies.

Evaluating the effect of Incorporating Chicken Feather Fibers on the Technological Properties of Eco-Friendly Compressed Earth Bricks

This paper investigates the feasibility of improving the performance of raw bricks by using chemically treated chicken feather fibers as a sustainable reinforcement material. Although numerous studies have already explored the use of chicken feathers in brick composites, this work is distinguished by the application of a novel chemical treatment involving formaldehyde and silane to enhance the fibers' compatibility with the clay matrix. The treated fibers were incorporated into raw brick samples at varying concentrations. The effects of fiber reinforcement on critical properties such as porosity, bulk density, compressive strength, and thermal conductivity were systematically analyzed. The results indicate that incorporating chemically treated chicken feather fibers reduces porosity and bulk density while increasing compressive strength within an optimal concentration range. Additionally, a significant reduction in thermal conductivity was observed, demonstrating the potential of these materials to improve thermal insulation in construction applications. This study highlights the promise of utilizing chicken feather waste, treated with formaldehyde and silane, as reinforcement in the production of eco-friendly bricks, with implications for sustainable construction practices.

Double modulation of the electric field in InGaAs/Si APD by groove rings for the achievement of THz gain-bandwidth product

Abstract Avalanche photodiode (APD) is commonly used as a receiver in optical communication and light detection and ranging (LIDAR), offering highly sensitive photodetection capabilities. A key strategy for improving the gain-bandwidth product (GBP) of the APD involves the optimization of the electric field distribution using the charge layer. However, traditional modulation methods to adjust the carrier transport and avalanche process using the charge layer often face challenges (inefficiency and non-uniformity). An InGaAs/Si APD based on the wafer bonding method with a GBP up to 1.03 terahertz (THz) is reported theoretically in this work. The charge layer and groove rings are inserted at the InGaAs/Si bonded interface to modulate the electric field in the APD effectively, demonstrating low dark current and reduced avalanche bias of the device. This approach induces a dramatic and rapid variation of the electric field at the interface while reducing the gradient of the electric field in the multiplication layer. Additionally, the indirect impact of the groove ring on mitigating the adverse effects of the lattice mismatch is pointed out, and the optimal doping concentration range of the charge layer is identified to enhance the modulation effect of the electric field for stronger impact ionization. These findings provide valuable insights for the next-generation InGaAs/Si APDs with high GBP for high-speed data transmission.

Growth Stimulation of Tropical Grass (Megathyrsus maximus Jacq.) by Humic Substances and Herbaspirillum seropedicae

This study aimed to evaluate the effect of soluble humic substances and plant-growth-promoting bacteria on the vegetative growth of Mombaça grass. A greenhouse experiment was conducted to study the effects of foliar applications of humic substances (0, 12, 24, 48, and 96 mg C L−1) on the growth of Mombaça fifteen days after germination. After determining the optimal concentration range, a field trial was carried out in which humic substances at the best concentration were applied simultaneously with Herbaspirillum seropedicae strain UENF-H19 fifteen days after germination in three replicates. The best growth of Mombaça in the greenhouse was obtained with 48 mg C of the humic substance L−1, which promoted a shoot fresh weight 80% higher than in the control treatment. The increase was almost identical to that observed during the 50-week field experiment in plots treated with humic substances combined with H. seropedicae. The treated plants produced an 81% higher shoot fresh weight than the control, with no dry mass, nitrogen content, or crude protein change during the one-year evaluation period. Despite the efficiency of the selected microbial inoculants under controlled-environment experiments, the agronomical significance under field conditions remains a subject of debate and improvement. The present study demonstrates that combining Herbaspirillum seropedicae with humic substances (plural) could significantly increase pasture production under field conditions.

Design method and experimental study on a novel self-sustaining internal combustion burner

Peak shaving represents a particular challenge with regard to coal-fired power plants, as methods to achieve stable, high-efficiency, and low-nitrogen-oxide combustion at ultralow loads remain unavailable. In this study, based on analysis of the ignition mechanism, heating mode, and theory of preheating method, we proposed a novel pulverized coal full-time self-sustaining internal combustion burner by combining the processes of plasma ignition, reverse jetting, and multi-stage ignition. A flame stability model for the burner's recirculation zone was established using the temperature change rate of the recirculation zone as a criterion. The ignition position of the stable self-sustained combustion of the pulverized coal gas stream was determined under various working conditions, and the length of the ignition core stage, a component of the burner inside which the pulverized coal gas stream achieves stable self-sustained combustion, was determined based on the calculated maximum ignition position; a self-sustaining internal combustion burner was then designed based on the ascertained length. Subsequently, we established an experimental system for the self-sustaining internal combustion burner and conducted tests in the load range of 25 %–100 %. Notably, the results of the pulverized coal self-sustained ignition position experiment were consistent with the computational results of the model. The self-sustaining internal combustion burner offers a quick start–stop feature, with the pulverized coal able to achieve stable self-sustained combustion after the plasma igniter shuts off. The resultant gas-phase products exiting the burner met the boiler's concentration requirements for enhanced nitrogen reduction, and the burner exhibited good anti-interference properties. The influence of the pulverized coal gas stream velocity and concentration on the self-sustained ignition was expounded. Under the experimental conditions, an optimal concentration range was ascertained for stable ignition of the pulverized coal gas stream, with the ignition position gradually advancing backward with increasing gas stream velocity. Together, our findings highlight the potential of the proposed burner design to support clean and efficient pulverized coal combustion in coal-fired power plants.

Hydroxychloroquine blood concentrations and effects in Chinese patients with IgA nephropathy.

Hydroxychloroquine (HCQ) is recommended for Chinese patients with immunoglobulin A nephropathy (IgAN). However, the relationship between HCQ blood concentration and the therapeutic effect for IgAN has not yet been defined. This study investigates the optimal and efficacious range of HCQ blood concentrations in Chinese patients with IgAN. Seventy-three patients with biopsy-proven IgAN who were at risk of progression were included in this study. Thirty-eight patients with IgAN were treated with HCQ plus an optimized renin-angiotensin-aldosterone system inhibitor (RAASi), and thirty-five patients received only RAASi. Blood HCQ concentration and 24-h proteinuria were examined at three and six months after treatment. The baseline proteinuria levels were comparable between the RAASi and HCQ groups. The HCQ group had lower 24-h proteinuria than the RAASi group three months after treatment, though the difference was not significant (p = 0.38). After six months, the median proteinuria level was significantly lower in the HCQ group than in the RAASi group (p < 0.05). The percentage reduction in 24-h proteinuria in the HCQ group was greater than that in the RAASi group at three (p < 0.05) and six months (p < 0.05). Hydroxychlorquine blood concentration and efficacy were positively correlated at three months (r = 0.428, p < 0.05) and six months (r = 0.48, p < 0.05). Moreover, the optimal blood concentration of HCQ for three-month efficacy was 418.96ng/mL and that for six-month efficacy was 582.48ng/mL. No serious adverse events were reported during HCQ treatment. Hydroxyhloroquine safely reduces proteinuria in Chinese patients with IgAN. The efficacy of HCQ is positively correlated with its blood concentration.

Silver phosphate-modified carbonate apatite honeycomb scaffolds for anti-infective and pigmentation-free bone tissue engineering

Bone regeneration using synthetic materials has a high rate of surgical site infection, resulting in severe pain for patients and often requiring revision surgery. We propose Ag3PO4-based surface modification and structural control of scaffolds for preventing infections in bone regeneration. We demonstrated the differences in toxicity and antibacterial activity between in vitro and in vivo studies and determined the optimal silver content in terms of overall anti-infection effects, bone regeneration, toxicity, and pigmentation. A honeycomb structure comprising osteoconductive and resorbable carbonate apatite (CAp) was used as the base scaffold. CAp in the scaffold surface was partially replaced with different concentrations of Ag3PO4 via controlled dissolution-precipitation reactions in an AgNO3 solution. Both bone regeneration and infection prevention were achieved at 860–2300 ppm of silver. Despite the absence of Ag3PO4, honeycomb scaffolds were less susceptible to infection, even under conditions where infection occurs in clinically used three-dimensional porous scaffolds. Regardless of in vitro cytotoxicity at >5200 ppm of silver, increasing the silver content to 21,000 ppm did not adversely affect in vivo bone formation and scaffold resorption or cause acute systemic toxicity. Rather, bone formation was enhanced with 5200 ppm of silver. However, pigmentation was observed at that concentration. Hence, we concluded that the optimal silver concentration range is 860–2300 ppm for anti-infective and pigmentation-free bone regeneration. Bone regeneration was achieved via surface modification, resulting in the rapid release of silver ions immediately after implantation, followed by gradual release over several months. The scaffold structure may also aid in preventing bacterial growth within the scaffolds.

Enhanced anaerobic digestion of waste-activated sludge by thermal-alkali pretreatment: a pilot-scale study.

The composition of waste-activated sludge (WAS) is complex, containing a large amount of harmful substances, which pose a threat to the environment and human health. The reduction and resource utilization of sludge has become a development demand in sludge treatment and disposal. Based on the technical bottlenecks in the practical application of direct anaerobic digestion technology, this study adopted two different thermal and thermal-alkali hydrolysis technologies to pretreat sludge. A pilot-scale experiment was conducted to investigate the experimental conditions, parameters, and effects of two hydrolysis technologies. This study showed that the optimal hydrolysis temperature was 70 °C, the hydrolysis effect and pH can reach equilibrium with the hydrolysis retention time was 4-8 h, and the optimal alkali concentration range was 0.0125-0.015 kg NaOH/kg dry-sludge. Thermal-alkali combination treatment greatly improved the performance of methane production, the addition of NaOH increased methane yield by 31.2% than that of 70 °C thermal hydrolysis. The average energy consumption is 75 kWh/m3 80% water-content sludge during the experiment. This study provides a better pretreatment strategy for exploring efficient anaerobic digestion treatment technologies suitable for southern characteristic sewage sludge.

An Assessment of the Performance Limitations of the Integrated QuantifilerTM Trio-HRM Assay: A Forensic Tool Designed to Identify Mixtures at the Quantification Stage.

Although guidelines exist for identifying mixtures, these measures often occur at the end-point of analysis and are protracted. To facilitate early mixture detection, we integrated a high-resolution melt (HRM) mixture screening assay into the qPCR step of the forensic workflow, producing the integrated QuantifilerTM Trio-HRM assay. The assay, when coupled with a prediction tool, allowed for 75.0% accurate identification of the contributor status of a sample (single source vs. mixture). To elucidate the limitations of the developed qPCR-HRM assay, developmental validation studies were conducted assessing the reproducibility and samples with varying DNA ratios, contributors, and quality. From this work, it was determined that the integrated QuantifilerTM Trio-HRM assay is capable of accurately identifying mixtures with up to five contributors and mixtures at ratios up to 1:100. Further, the optimal performance concentration range was found to be between 0.025 and 0.5 ng/µL. With these results, evidentiary-like DNA samples were then analyzed, resulting in 100.0% of the mixture samples being accurately identified; furthermore, every time a sample was predicted as a single source, it was true, giving confidence to any single-source calls. Overall, the integrated QuantifilerTM Trio-HRM assay has exhibited an enhanced ability to discern mixture samples from single-source samples at the qPCR stage under commonly observed conditions regardless of the contributor's sex.

Design and fabrication of magnetic cross-linked laccase aggregate using superparamagnetic metal-organic frameworks for phenol removal

Phenolic pollutants represent a significant environmental concern due to their widespread presence in industrial effluents, agricultural runoff, and urban waste streams. Enzymatic bioremediation emerges as a promising approach for the efficient removal of phenolic pollutants from contaminated environments. Laccases exhibit remarkable catalytic capabilities in degrading phenolic compounds into less harmful or even inert products. In this study, magnetic cross-linked laccase aggregate was prepared using superparamagnetic metal-organic frameworks and then was applied for phenol removal. The obtained results showed that the magnetic cross-linked laccase aggregate retains its activity across a broad pH range. Interestingly, (NH4)2SO4 exhibited a positive influence on enzyme activity, resulting in a relative activity of 137.7 %. The findings suggest that an optimal concentration range of 0.4–0.8 % can achieve maximum enzyme activity while avoiding potential negative impacts associated with excessive cross-linking. Optimal pH and temperature conditions were identified for enhanced phenol removal efficiency as pH 4.5 and 45℃, respectively. The investigation revealed the remarkable reusability of the cross-linked enzyme over multiple cycles. Harnessing the power of enzymes for phenolic pollutant remediation holds immense promise for mitigating environmental pollution and safeguarding public health.

Oleanolic Acid Promotes the Formation of Probiotic Escherichia coli Nissle 1917 (EcN) Biofilm by Inhibiting Bacterial Motility.

Probiotic biofilms have been beneficial in the fight against infections, restoring the equilibrium of the host's gut microbiota, and enhancing host health. They are considered a novel strategy for probiotic gut colonization. In this case, we evaluated the effects of various active substances from traditional Chinese medicine on Escherichia coli Nissle 1917 (EcN) to determine if they promote biofilm formation. It was shown that 8-64 μg/mL of oleanolic acid increased the development of EcN biofilm. Additionally, we observed that oleanolic acid can effectively suppress biofilm formation in pathogenic bacteria such as Salmonella and Staphylococcus aureus. Next, we assessed the amount of EcN extracellular polysaccharides, the number of live bacteria, their metabolic activity, the hydrophobicity of their surface, and the shape of their biofilms using laser confocal microscopy. Through transcriptome analysis, a total of 349 differentially expressed genes were identified, comprising 134 upregulated and 215 downregulated genes. GO functional enrichment analysis and KEGG pathway enrichment analysis revealed that oleanolic acid functions are through the regulation of bacterial motility, the iron absorption system, the two-component system, and adhesion pathways. These findings suggest that the main effects of oleanolic acid are to prevent bacterial motility, increase initial adhesion, and encourage the development of EcN biofilms. In addition, oleanolic acid interacts with iron absorption to cooperatively control the production of EcN biofilms within an optimal concentration range. Taking these results together, this study suggests that oleanolic acid may enhance probiotic biofilm formation in the intestines, presenting new avenues for probiotic product development.

GC-MS determination of polychlorinated biphenyls in water using extractive freezing-out of analytes

A method for determining polychlorinated biphenyls (PCBs) in water using the method of concentrating analytes through extractive freezing-out under the effect of a centrifugal forces (EFC) has been developed. A mathematical model for analyte extraction using a three-factor Box-Behnken design demonstrated that the content of acetonitrile in the extraction mixture is a significant factor, whereas the degree of PCBs chlorination and the concentration of analytes are insignificant parameters. Analysis of the surface area of the model allowed the determination of the optimal range of the acetonitrile concentration, which fell between 14 and 21%. A 15% content of acetonitrile in the extraction mixture provided maximum extraction efficiency for 7 different PCBs (&gt;92%) across a wide range of analyte concentrations (1.0 – 5000 ng/liter). The relative standard deviations in the repeatability and reproducibility range from 4.2 to 6.8% and 5.3 to 8.1%, respectively, the accuracy of analyte determination being 10 – 15%. Petroleum hydrocarbons were not extracted into the acetonitrile extract and did not interfere with the determination of PCBs, which provided longer operation of the detector without any loss in the sensitivity. Co-extraction of polycyclic aromatic hydrocarbons and chlorinated pesticides did not affect the extraction of PCBs from water (95 – 100%) and did not touch on the metrological indicators of the determination procedure.

Development and Validation of Fast and Sensitive RP-HPLC Stability-Indicating Method for Quantification of Piroxicam in Bulk Drug.

A simple, rapid, sensitive, and cost-effective green solvent-assisted reverse-phase high-performance liquid chromatographic technique, coupled with a photodiode array detector, was developed and validated for the estimation of piroxicam (PRXM). The chromatographic separation was achieved by using a C-18 (250 × 4.6) mm, 5-μm stationary phase and a mobile phase consisting of methanol and 0.1% ortho-phosphoric acid in water in a ratio of (80:20) v/v at a flow rate of 1ml/min. The detection was carried out at a wavelength of 254nm with a constant injection volume of 10μL throughout the analysis. The calibration curve was observed to be linear over the optimum concentration range of 50-300μgmL-1, with an R2 value of 0.9995. The developed method was validated as per the International Council for Harmonisation (ICH) Q2 (R1) guideline. Various parameters like selectivity/specificity, accuracy/recovery, linearity, precision, detection limit, quantitation limit, robustness and stability of analyte in solution were performed for the method validation. The PRXM was evaluated under stressed conditions, including acidic, basic, oxidative, thermal and photolytic, as per ICH Q1 (R2) guidelines. Significant degradation was observed in acidic and basic degradation conditions. Conversely, the drug substance showed stability when exposed to oxidative, photolytic and thermal degradation conditions.

The microstructure and corrosion resistance of Mg–Zn-0.5Ag-xCa (x=0, 0.5, 1.0, 1.5 wt%) alloys in Hank's solution

Due to the excellent biocompatibility of Zn, Ag, and Ca, these elements were chosen for the development of a Mg–Zn–Ag–Ca alloy system for biomedical applications. This study studied the effect of Ca on the microstructure and corrosion behavior of as-cast Mg–Zn-0.5Ag-xCa alloy. The composition and microstructure of the alloys were analyzed using metallographic microscopy, scanning electron microscopy, transmission electron microscopy, and X-ray diffractometry. The alloys were immersed in Hank's solution for weight loss experiments to analyze the corrosion rate and micro-corrosion morphology of alloys with different Ca contents. It was observed that with the increase of Ca content, grain refinement and the amount of the second phase increased. Corrosion tests in Hank's solution demonstrated that a minor addition of Ca could reduce the corrosion rate, but the rate increased sharply once the Ca content exceeded 1.0 wt%. Considering corrosion performance, the optimal range of Ca concentration was determined to be 1.0 wt% to 1.5 wt%.

Relationship between hydro-environmental variables and Coilia nasus catch in a highly turbid macrotidal estuary in Japan

The effect of estuarine hydro-environmental parameters and tidal phases on the fish catch in the macrotidal Chikugo River estuary was investigated. This study focuses on the catch data of Etsu (Coilia nasus) fish, obtained during their spawning season from 2009 to 2020, employing traditional fishing techniques at a site situated 14.6–16 km upstream from the river mouth. It analyses various hydro-environmental parameters and identifies optimal ranges of environmental parameters. The optimal range of salinity (0.04–0.2) and suspended sediment concentration (SSC, 16–118 mg/L) indicated a higher fish catch at the saltwater-freshwater interface and upstream of the estuarine turbidity maximum (ETM) zone. By developing a generalized additive model (GAM) to analyze the relationship between CPUE and environmental parameters, the study assesses the relative importance of each variable in explaining CPUE variance. GAM exhibited a reasonable predictive capability (R2 = 0.509) and indicated the relative importance of each variable (SSC-24.69%, salinity-21.81%, temperature-24.41%, discharge-9.16%, and MTR-19.91%) in explaining the CPUE variance. Additionally, it aims to verify the maturity status and spawning migration patterns of C. nasus fish through standard-length distribution analysis during the spawning season. The standard-length distribution and comparison with previous literature confirmed that fishes caught by the fisherman belong to the category of matured fishes aged 2–3 years. The results indicated that the high CPUE of matured C. nasus at the upstream of ETM and freshwater-saltwater interface was related to the spawning migration and not to their feeding behaviour at the ETM. This research contributes to fisheries management strategies and conservation efforts in the Chikugo River estuary by providing valuable guidance for habitat restoration, informing fishing regulations, and understanding the behaviour of C. nasus.