Development and study of the stability of comenic acid solutions

Introduction. The article presents the development of solutions based on the comenic acid substance. The criteria of the studied compositions that affect their stability during storage are evaluated within the framework of the Quality-by-Design concept. The optimal compositions of comenic acid solutions have been established.Aim. The purpose of the study is to develop solutions based on the comenic acid substance and determine the most stable variants of execution.Materials and methods. The study of comenic acid solutions was carried out by using a laboratory pH meter PB-11-P11 (SARTORIUS, Germany) and a liquid/ion chromatograph "Stayer" ("Akvilon" JSC, Russia).Results and discussion. The study made it possible to determine the most stable compositions of solutions based on the comenic acid substance and to establish optimal indicators of their stability criteria. It was found that solutions of comenic acid are the most stable in the pH range: from 4.0 to 6.0. At the same time, regardless of the studied methods of neutralization of comenic acid, solutions are unstable at concentrations of 25 mg/ml or more.Conclusion. As a result of the study, the optimal compositions of solutions based on the comenic acid substance were determined. A comparative analysis of excipients that increase the solubility of comenic acid in aqueous solvents is performed. The stability criteria of the studied solutions are established and their values for ensuring the stability of the developed drug are determined.

A Paleoclimate Reconstruction of the Little Ice Age to Modern Era Climate Conditions in the Eastern Ross Sea, Antarctica as Captured in the RICE Ice Core

<p>The Little Ice Age (LIA) (1400-1850 AD) represents one of the most significant climatic shifts over the past 5000 years. Previous studies from Antarctica indicate generally cooler and stormier conditions during this period, but this pattern shows distinct spatial and temporal variability. The Roosevelt Island Climate Evolution (RICE) ice core provides a new opportunity to study the drivers behind this variability at annual/seasonal resolution, in a relatively under-sampled and climatically sensitive region in the eastern Ross Sea. Contrary to previous studies, isotope measurements suggest warm conditions during the LIA at Roosevelt Island. This study presents analysis of eight major ions (Na⁺, Mg²⁺, Ca²⁺, K⁺, MS⁻, Cl⁻, NO₃⁻, SO₄²⁻) using both Ion Chromatograph and ICP-MS data, in order to reconstruct the atmospheric circulation pattern, sea ice extent and marine primary productivity across this LIA to Modern Era (ME) at Roosevelt Island. The dataset is tied to a robust age model allowing annual dating and the opportunity to accurately reconstruct rates of change during this ME-LIA. Challenges revolving around the calibration of the Ion Chromatograph are also discussed. The major ion record determines whether the lack of cooling in the Roosevelt Island core implied by the stable isotopes represents a true temperature anomaly or whether the atmospheric circulation pattern caused an isotopic enrichment that masks an underlying cooling. It was determined that Roosevelt Island experienced during the LIA (i) an increase in marine air mass intrusions along with weaker katabatic winds compared to the 200 years prior, (ii) decreased biological productivity and (iii) increased sea ice. From the 1850-1880s to 1992 AD, there is a shift to reduced marine winds, increased katabatics, increased biological productivity and decreased sea ice until 1992. In the wider Ross Sea context, this suggests an east-west divide in terms of the dominance of katabatics versus marine wind influence. This divide is attributed with the warming signal seen in the RICE record in the Eastern Ross Sea and the cooling in the Western Ross Sea records. It is also likely linked to the influence of climate indices on the depth/position of the Amundsen Sea Low.</p>

A Paleoclimate Reconstruction of the Little Ice Age to Modern Era Climate Conditions in the Eastern Ross Sea, Antarctica as Captured in the RICE Ice Core

<p>The Little Ice Age (LIA) (1400-1850 AD) represents one of the most significant climatic shifts over the past 5000 years. Previous studies from Antarctica indicate generally cooler and stormier conditions during this period, but this pattern shows distinct spatial and temporal variability. The Roosevelt Island Climate Evolution (RICE) ice core provides a new opportunity to study the drivers behind this variability at annual/seasonal resolution, in a relatively under-sampled and climatically sensitive region in the eastern Ross Sea. Contrary to previous studies, isotope measurements suggest warm conditions during the LIA at Roosevelt Island. This study presents analysis of eight major ions (Na⁺, Mg²⁺, Ca²⁺, K⁺, MS⁻, Cl⁻, NO₃⁻, SO₄²⁻) using both Ion Chromatograph and ICP-MS data, in order to reconstruct the atmospheric circulation pattern, sea ice extent and marine primary productivity across this LIA to Modern Era (ME) at Roosevelt Island. The dataset is tied to a robust age model allowing annual dating and the opportunity to accurately reconstruct rates of change during this ME-LIA. Challenges revolving around the calibration of the Ion Chromatograph are also discussed. The major ion record determines whether the lack of cooling in the Roosevelt Island core implied by the stable isotopes represents a true temperature anomaly or whether the atmospheric circulation pattern caused an isotopic enrichment that masks an underlying cooling. It was determined that Roosevelt Island experienced during the LIA (i) an increase in marine air mass intrusions along with weaker katabatic winds compared to the 200 years prior, (ii) decreased biological productivity and (iii) increased sea ice. From the 1850-1880s to 1992 AD, there is a shift to reduced marine winds, increased katabatics, increased biological productivity and decreased sea ice until 1992. In the wider Ross Sea context, this suggests an east-west divide in terms of the dominance of katabatics versus marine wind influence. This divide is attributed with the warming signal seen in the RICE record in the Eastern Ross Sea and the cooling in the Western Ross Sea records. It is also likely linked to the influence of climate indices on the depth/position of the Amundsen Sea Low.</p>

Three-channel ion chromatograph for improved metabolic evaluation of urolithiasis

Background Urolithiasis is a multi-etiological disease resulting from a combination of environmental and genetic factors. One of the most challenging aspects of this disease is its high recurrence rate. For most patients, an in-depth metabolic evaluation may reveal the presence of urinary stones. The fact that different urinary stone-related compounds (USRCs) are measured by different methods renders the metabolic evaluation of urolithiasis quite tedious and complex. Methods A three-channel ion chromatograph (IC) that automatically measures the concentration of common metabolic indicators of urolithiasis in urine (i.e., oxalate, citrate, uric acid, calcium, and magnesium) was developed to improve the efficiency. To validate its precision and specificity, standard curves were prepared using working solution of these indicators. 100 standard solutions of these indicators were measured with our new IC and three other ICs as the control instruments; analyte concentrations in 100 24-h urine samples from volunteers and 135 calculi patients were also measured. Results All analytes had good linear relationships in concentration ranges of 0–10 mg/L. The precision experiments in the standard and urine samples showed that the measurement errors of the newly developed IC were all less than 5%. In urine, the recovery rate ranged from 99.6 to 100.4%, the coefficient of variation ranged from 1.39 to 2.99%, and the results matched between our newly developed IC and the control ICs. The results of the efficiency test showed that we can finish the analysis at the average number of 14 people per day with the new IC. While the average number in the control group is 3.85/day (p = 0.000). Conclusions Overall, this multi-channel system significantly improves the efficiency of metabolic evaluation while retaining accuracy and precision.

Study on the Morphological Change and Reduction of Nitrogen and Phosphorous in Litter and Compost of Cowshed

Litter and compost were obtained at a cowshed of a livestock farm in Andong city in Korea. The morphological change of nitrogen and phosphorous from these samples were examined and suggested a more useful and realistic way for reducing them. Constituents and their content of sample were identified by XRF. The nitrite ion (NO2 −), nitrate ion (NO2 −) and phosphate ion (PO4 3−) and ammonium ion (NH4 +), total phosphorous (T-P) and total nitrogen (T-N) released from sample were analyzed using ion chromatograph and UV/Vis spectrometry. As the results of this study, the ammonia in the early stage of cow excretion is a need to make an ammonia gas state that can be immediately volatile by increasing the pH. Nitrogen and phosphorous, the main source of nutrition in green algal bloom can be reduced by transforming insoluble salts such as calcium phosphate (CaHPO4·3H2O) and struvite (NH4MgPO4·6H2O), respectively, with addition of Ca and Mg after stimulating fermentation of compost.