Water Buffer Research Articles

Deep Eutectic Solvents based green approach for bioactive molecules recovery from Spirulina.

Spirulina is a unicellular microalga, characterized by blue/green color, that has received significant attention for its interesting nutritional composition. Phenolic compounds and phycocyanin (PC) are responsible for the many biological activities of Spirulina. Spirulina phenolic compounds are usually extracted using organic solvents, while PC is extracted with water or phosphate buffer solution, obtaining an extract characterized by low stability and low purity. Deep Eutectic Solvents (DESs) are green solvents, widely applied for bioactive molecules extraction, composed by two or more molecules which act as hydrogen bond acceptor or hydrogen bond donor to create an eutectic mixture. A Natural Deep Eutectic Solvent (NADES), is a DES composed only by natural compounds. This work aimed to optimize a green extraction procedure based on NADES to obtain an extract rich in phenolic compounds and PC from Spirulina. The application of NADESs as extraction solvents is an important strategy for recovering phenolic compounds and to increase and stabilize the protein PC. The optimized extraction procedure involved to use a betaine-glucose NADES under the following conditions: matrix-to-solvent ratio of 1:20 (w/w), temperature of 50 °C and one hour as extraction time. The developed extraction procedure guaranteed to recover a phenolic compounds and PC quantity of 11.77 ± 1.23 mg GAE (gallic acid equivalents) and 27.56 ± 2.46 g per g of Spirulina powder respectively. PC in the NADES extract degraded more slowly than in an aqueous extract. The extract phenolic compounds profile was determined through high performance liquid chromatography coupled with mass spectrometry analysis.

Water pervious concrete pavement blocks: durable structures for an integrated water policy

Water pervious pavement blocks are a durable and ecological solution to prevent water run off, to minimize the risk of flooding and to increase the efficiency of water purification. The application of water pervious pavement blocks on a permeable base and/or sub base allows buffering of the rainwater in the structure and infiltration or retarded outflow to the ground or infiltration system. This paper presents the results of a research project, conducted at the BRRC during 4 years. The efficiency of water buffering and infiltration in relation to the choice of material is investigated in the laboratory, on a test parking lot and on site. To allow a good choice of the materials and the application site and to control the efficiency on site, different test methods are optimized. Results for different types of concrete pavement blocks (pervious blocks, blocks with enlarged joints or drainage holes), different types of base layer (hydraulic bounded or unbounded materials) and different types of sand layer and jointing materials are looked at. Finally this paper focuses on several applications in Belgium, where measurements have shown a good behavior of the structure and a good durability of the permeability. Data from newly constructed projects, as well as projects in use for more than eight years are presented.

Synthesis and Characterization of Ru(II)−NSHC Catalysts Bearing Thiamine Analogs in Water‐Solvent Transfer Hydrogenation Catalysis

AbstractThiamine analogues with 3‐methyl and 4‐(2‐hydroxyethyl) substituents on the backbone of thiazole ring, were used to synthesize monodentate Ru(II)‐thiazolylidene complexes in a single step via transmetalation under mild conditions. These novel complexes catalyze the conversion of ketones and aldehydes to alcohols by transfer hydrogenation in a 5 : 2 HCO2H/NEt3 buffer in water. However, their efficiency was found to be much lower than the thiamine‐derived bidentate Ru(II) complexes, which strongly indicates that the ‘N−H’ plays a crucial role in the reaction.

Novel RP-HPLC method for simultaneous determination of dapagliflozin and teneligliptin in tablet formulation and identification of degradation products by LC-MS/MS

BackgroundDiabetes mellitus affects millions globally, necessitating effective management strategies. Glenmark Pharmaceutical Limited introduced a fixed-dose combination of teneligliptin and dapagliflozin in 2022 to address this need. However, existing methods for their simultaneous detection are limited, lacking forced degradation studies essential for assessing drug stability.ResultsA stability-indicating RP-HPLC method was developed for the simultaneous determination of dapagliflozin and teneligliptin in pharmaceutical formulations. The separation was efficiently achieved employing a Zorbax Eclipse Plus C18 column (150 mm × 4.6 mm, 5 µm). The mobile phase comprised a mixture of 10 mM ammonium acetate buffer in water, methanol, and acetonitrile in a suitable proportion and delivered at a flow rate of 0.6 mL/min. Detection of the isocratic eluents was performed at 224 nm using a photodiode array (PDA) detector. Validation against various stress conditions, as per ICH guidelines, revealed significant degradation of teneligliptin primarily under acidic, basic, and oxidative stress. Moreover, liquid chromatography tandem mass spectrometry (LC-MS/MS)-based characterization was conducted for the primary degradation products of teneligliptin generated under acidic, basic, and oxidative conditions.ConclusionsThe developed RP-HPLC method with a stability-indicating approach provides an efficient means for the simultaneous determination of dapagliflozin and teneligliptin in pharmaceutical formulations. The significant degradation was observed under various stress conditions and also successfully separated the degradation products by this method. The proposed method directly applied for the characterization of degradation products and based on LC-MS/MS data the structure of degradation products was generated and also degradation pathways under various stress conditions were predicted. The proposed method ensured accurate and precise results in quality control process in pharmaceutical industry, and adherence to ICH validation guidelines affirms its reliability in assessing the stability of these compounds.

Drinking water buffer intensity simulator (BIS): Development and practical simulations

AbstractAn established body of research over many decades has identified the importance of both bulk‐water and pipe scale surface microenvironment buffering to meet distribution system pH targets and reduce corrosivity toward metallic piping and components. Buffer intensity quantifies the ability of water to resist pH changes, and the greater the buffer intensity, the more resistant the water is to pH changes. To provide a practical tool for exploring buffer intensity, a buffer intensity simulator (BIS) was implemented in open‐source R code, incorporating typical chemical species (e.g., carbonate and orthophosphate) that contribute to drinking water buffer intensity along with temperature and ionic strength impacts. The BIS was verified against a parallel spreadsheet implementation and is publicly available at https://github.com/USEPA/BIS. Simulations were conducted to illustrate impacts related to buffer intensity using three practical scenarios: carbonate buffering in drinking waters, temperature impacts, and free ammonia presence from chloramine use and/or source water presence.

Method Development and Validation of Luliconazole Bulk Drug Using Reverse Phase - HPLC Technique

Objective: To develop and validate the RP- HPLC method for determining Luliconazole in bulk and pharmaceutical formulations. Methods: Following the International Conference on Harmonization (ICH) guidelines, a sensitive, accurate, and specific reversed-phase HPLC technique was created and validated for the detection of Luliconazole. Using high-performance liquid chromatography, this drug was examined. A better separation of the drug was achieved by using Agilent Eclipse XDB C (4.6mm x 250mm, 5µm) with a mobile phase consisting of a mixture of Acetonitrile and Buffer in HPLC water. The ratio of 30:70 v/v (Formic acid and Acetonitrile) at a flow rate of 1.0 ml/ min and the detection was at the wavelength 295 nm using a Photodiode Arrays Detector. The planned method was able to produce good quality separation of the drug and its degradation products with sharp peaks. Findings: Luliconazole had a retention time of 2.38 ± 0.127 minutes. The technique was linear in the range of 10-100 µg/ml, with a correlation (r2) of 0.9995 and a run duration of 4 minutes. The method limit of detection (LOD) and limit of quantification (LOQ) were set at 0.1 and 1 g/ml, respectively. The method accuracy and system precision were estimated, and the findings were calculated as percentage RSD values, which were found to be limitations. Luliconazole recovery was 100% confirming the method's efficiency. Novelty: The presented approach was innovative and successfully fulfilled all validation requirements, including linearity, robustness, accuracy, reduced retention, and run time. This suggests that the method is appropriate for identifying the stability of luliconazole in bulk and pharmaceutical formulations. Keywords: RP-HPLC, Transferosome, ICH guidelines, Validation, Luliconazole

Molecular Dynamics Simulations Reveal How Competing Protein-Surface Interactions for Glycine, Citrate, and Water Modulate Stability in Antibody Fragment Formulations.

The design of stable formulations remains a major challenge for protein therapeutics, particularly the need to minimize aggregation. Experimental formulation screens are typically based on thermal transition midpoints (Tm), and forced degradation studies at elevated temperatures. Both approaches give limited predictions of long-term storage stability, particularly at low temperatures. Better understanding of the mechanisms of action for formulation of excipients and buffers could lead to improved strategies for formulation design. Here, we identified a complex impact of glycine concentration on the experimentally determined stability of an antibody Fab fragment and then used molecular dynamics simulations to reveal mechanisms that underpin these complex behaviors. Tm values increased monotonically with glycine concentration, but associated ΔSvh measurements revealed more complex changes in the native ensemble dynamics, which reached a maximum at 30 mg/mL. The aggregation kinetics at 65 °C were similar at 0 and 20 mg/mL glycine, but then significantly slower at 50 mg/mL. These complex behaviors indicated changes in the dominant stabilizing mechanisms as the glycine concentration was increased. MD revealed a complex balance of glycine self-interaction, and differentially preferred interactions of glycine with the Fab as it displaced hydration-shell water, and surface-bound water and citrate buffer molecules. As a result, glycine binding to the Fab surface had different effects at different concentrations, and led from preferential interactions at low concentrations to preferential exclusion at higher concentrations. During preferential interaction, glycine displaced water from the Fab hydration shell, and a small number of water and citrate molecules from the Fab surface, which reduced the protein dynamics as measured by root-mean-square fluctuation (RMSF) on the short time scales of MD. By contrast, the native ensemble dynamics increased according to ΔSvh, suggesting increased conformational changes on longer time scales. The aggregation kinetics did not change at low glycine concentrations, and so the opposing dynamics effects either canceled out or were not directly relevant to aggregation. During preferential exclusion at higher glycine concentrations, glycine could only bind to the Fab surface through the displacement of citrate buffer molecules already favorably bound on the Fab surface. Displacement of citrate increased the flexibility (RMSF) of the Fab, as glycine formed fewer bridging hydrogen bonds to the Fab surface. Overall, the slowing of aggregation kinetics coincided with reduced flexibility in the Fab ensemble at the very highest glycine concentrations, as determined by both RMSF and ΔSvh, and occurred at a point where glycine binding displaced neither water nor citrate. These final interactions with the Fab surface were driven by mass action and were the least favorable, leading to a macromolecular crowding effect under the regime of preferential exclusion that stabilized the dynamics of Fab.

Biomass Carbon Dots as Fluorescent Probes for Fast and Highly Selective Detection of Fe3 + in Water Media.

In this study, a novel fluorescent probe for the rapid and highly selective detection of Fe3 + based on biomass carbon dots (b-CDs) was developed. The b-CDs were obtained via one-step hydrothermal synthesis by utilizing laurel fallen leaves. And the as-synthesized b-CDs were applied for sensing Fe3+ based on fluorescence (FL) quenching effect both in water and phosphate buffer solution (PBS) with a wide linear range from 1 µM to 300 µM, the detection limits (LODs) respectively to be 0.34 µM in water and 0.48 µM in PBS solution. The FL intensity of b-CDs was quenched fleetly within 1min after adding Fe3+. The sensing mechanism of the b-CDs + Fe3+ system can be attributed to the internal filtration effect (IFE) mechanism and the electron transfer (ET) between b-CDs and Fe3+ in water, and only the IFE mechanism in PBS solution based on multiple experimental evidences. Moreover, the as-proposed probe was successfully adopted for monitoring Fe3+ in lake water and tap water samples. This research shows some merits of economic, simplicity, green, high selectivity, and quick response for Fe3+ determination, and provides an approach for the water quality monitoring of Fe3+ and the effective utilization of waste biological materials.

Liquid-liquid extraction solvent selection for comparing illegal drugs in whole blood and dried blood spot with LC-MS-MS.

This study focused on the simultaneous detection of amphetamine, 3,4-methylenedioxy methamphetamine, morphine, benzoylecgonine, and 11-nor-9-carboxy-tetrahydrocannabinol in whole blood and dried blood spot (DBS). It is aimed to select a solvent mixture for liquid-liquid extraction technique employing liquid chromatography-tandem mass spectrometry (LC-MS-MS). The obtained DBS results were compared with the whole blood samples results. A simple, rapid, and reliable LC-MS-MS method was developed and validated for all analytes in whole blood and DBS. LC was performed on a Hypersil Gold C18 column with an initial gradient of 0.01% formic acid, 5 mM ammonium format buffer in water, and acetonitrile at 0.3 ml/min with 7.5 min runtime. A methanol:acetonitrile (40:60 v/v) mixture was selected for both matrices. Limit of quantitation (LOQ) values were 10-25 ng/mL; linear ranges were LOQ-500 ng/ml for all analytes; correlation coefficients were greater than 0.99, and all calibrator concentrations were within 20%. Analytical recovery in blood and DBS ranged from 84.9% to 113.2% of the expected concentration for both intra- and inter-day. Analytes were stable for 1, 10, and 30 days after three freeze/thaw cycles. It was determined that the variances of the results obtained with the two matrices in the comparison study were equal for each analyte, and the results were highly correlated (r = 0.9625). A sensitive, accurate, and reliable chromatographic method was developed to determine amphetamine, 3,4-methylenedioxy methamphetamine, morphine, benzoylecgonine, and cannabis, by performing the same preliminary steps with whole blood and dried blood spots. It was observed that the results obtained in these two matrices were compatible and interchangeable when statistically compared.

Research on the Spatial–Temporal Distribution and Morphological Characteristics of Ancient Settlements in the Sichuan Basin

An investigation into the spatial–temporal distribution characteristics of ancient settlements and their relationship with the environment in the Sichuan Basin can enhance our understanding of the evolution of the regional human–land relationship. Utilizing kernel density analysis by GIS, this paper obtained the spatial distribution characteristics of 1100 settlements in the Neolithic, Shang–Zhou, and Qin to Southern Dynasties periods. Subsequently, a GIS spatial analysis was performed to examine the distribution of these settlements in relation to the natural environment, focusing on four aspects: elevation, slope, aspect, and water buffer zone. The results demonstrate that: (1) The distribution of settlements from the Neolithic to the Southern Dynasties has expanded from the Chengdu Plain in the west and the Xiajiang Area in the east to the hilly areas in the center. (2) The settlements in the Neolithic and Shang–Zhou periods are predominantly located at elevations between 300–600 m, slopes between 0–3°, aspects between 135–225°, distances to rivers between 0–1000 m, and soil choice on Luvisols, Cambisols, Regosols, and Anthrosols. The influence of aspect on settlements during the Qin–Southern Dynasties period was notably reduced. The settlements mainly grow in the Chengdu Plain and the smaller plains along the river from the Neolithic to the Southern Dynasties in the Sichuan Basin. (3) The emergence and advancement of primitive agriculture, the construction of early water conservancy facilities, commercial and trade exchanges, and the establishment of regimes led to a shift from a double core to a more dispersed distribution in the Sichuan Basin from the Neolithic to the Southern Dynasties periods. The evolution of settlements reflects the adaption and competition of the residents to the natural environment in the Sichuan Basin. Furthermore, it provides insights into the complex social development in the region, ranging from the formation of early states to the establishment of the Qin and Han Empires.

Extraction and Concentration of Spirulina Water-Soluble Metabolites by Ultrafiltration.

Spirulina (Arthospira platensis) is known for its rich content of natural compounds like phycocyanin, chlorophylls, carotenoids, and high protein levels, making it a nutrient-dense food. Over the past decade, research has aimed to optimize the extraction, separation, and purification of these valuable metabolites, focusing on technologies such as high-pressure processing, ultrasound-assisted extraction, and microwave-assisted extraction as well as enzymatic treatments, chromatographic precipitation, and membrane separation. In this study, various extraction methods (conventional vs. ultrasound-assisted), solvents (water vs. phosphate buffer), solvent-to-biomass ratios (1:5 vs. 1:10), and ultrafiltration (PES membrane of MWCO 3 kDa, 2 bar) were evaluated. The quantities of total protein, phycocyanin (PC), chlorophyll a (Cla), and total carotenoids (TCC) were measured. The results showed that ultrasound-assisted extraction (UAE) with phosphate buffer at a 1:10 ratio yielded a metabolite-rich retentate (MRR) with 37.0 ± 1.9 mg/g of PC, 617 ± 15 mg/g of protein, 0.4 ± 0.2 mg/g of Cla, and 0.15 ± 0.14 mg/g of TCC. Water extraction in the concentration process achieved the highest concentrations in MRR, with approximately 76% PC, 92% total protein, 62% Cla, and 41% TCC. These findings highlight the effective extraction and concentration processes to obtain a metabolite-rich retentate from Spirulina biomass, reducing the volume tenfold and showing potential as a functional ingredient for the food, cosmetic, and pharmaceutical industries.

Magnetic Nanoparticles with On-Site Azide and Alkyne Functionalized Polymer Coating in a Single Step through a Solvothermal Process.

Background/Objectives: Magnetic Fe3O4 nanoparticles (MNPs) are becoming more important every day. We prepared MNPs in a simple one-step reaction by following the solvothermal method, assisted by azide and alkyne functionalized polyethylene glycol (PEG400) polymers, as well as by PEG6000 and the polyol β-cyclodextrin (βCD), which played a crucial role as electrostatic stabilizers, providing polymeric/polyol coatings around the magnetic cores. Methods: The composition, morphology, and magnetic properties of the nanospheres were analyzed using Transmission Electron and Atomic Force Microscopies (TEM, AFM), Nuclear Magnetic Resonance (NMR), X-ray Diffraction Diffractometry (XRD), Fourier-Transform Infrared Spectroscopy (FT-IR), Matrix-Assisted Laser Desorption/Ionization (MALDI) and Vibrating Sample Magnetometry (VSM). Results: The obtained nanoparticles (@Fe3O4-PEGs and @Fe3O4-βCD) showed diameters between 90 and 250 nm, depending on the polymer used and the Fe3O4·6H2O precursor concentration, typically, 0.13 M at 200 °C and 24 h of reaction. MNPs exhibited superparamagnetism with high saturation mass magnetization at room temperature, reaching values of 59.9 emu/g (@Fe3O4-PEG6000), and no ferromagnetism. Likewise, they showed temperature elevation after applying an alternating magnetic field (AMF), obtaining Specific Absorption Rate (SAR) values of up to 51.87 ± 2.23 W/g for @Fe3O4-PEG6000. Additionally, the formed systems are susceptible to click chemistry, as was demonstrated in the case of the cannabidiol-propargyl derivative (CBD-Pro), which was synthesized and covalently attached to the azide functionalized surface of @Fe3O4-PEG400-N3. Prepared MNPs are highly dispersible in water, PBS, and citrate buffer, remaining in suspension for over 2 weeks, and non-toxic in the T84 human colon cancer cell line, Conclusions: indicating that they are ideal candidates for biomedical applications.

Mg2+ - Ca2+ chelating citric acid crosslinked gelatin, a bone adhesive composed of hydroxyapatite and calcined dolomite: Physicochemical characteristics and in-vitro biological activity

Hydroxyapatite-based bone adhesives have strong bond strength and good adsorbability, however, they also have some disadvantages such as poor mechanical strength, fast curing reaction rate and high exothermic strength, which limit their wide application in bone tissue engineering. In this study, hydroxyapatite-based bone adhesive was prepared by solid-liquid blended crosslinking followed by heating. The prepared bone adhesive has two components: (i) is a mineral composed of calcined dolomite and montmorillonite and (ii) is organic composite composed of citric acid and gelatine. The optimum solid-liquid ratio (0.50 g/mL) of the bone adhesive was determined based on the bond strength of nano-hydroxyapatite/calcined dolomite/citric acid/gelatin system. The best physicochemical properties of the bond adhesive were obtained when the composition of the bone adhesive was as follows: 20 wt% citric acid, 17 wt% gelatin and 12 wt% calcined dolomite. The acquired curing time of bone adhesive was 10.5 min, comparable to the necessity for surgery (5–30 min); moreover, the adhesive strength and compressive strength of the bone adhesive were 12.18 MPa and 9.36 MPa respectively, obtained after being placed in the air for 168 h; besides, the porosity (16.8 %) was found quite suitable. Upon this, a certain amount of montmorillonite was added with calcined dolomite to prepare bone adhesive, resulting reduction in the adhesive strength (10.19 MPa) and compressive strength (7.109 MPa), but improved the biocompatibility of the system. The absorbency of the hydroxyapatite-based bone adhesives in deionized water and Tris-HCl buffer solution was found to be 27.19 % and 18.68 %, respectively, ascertaining that such bone adhesives are efficient in absorbing certain blood and tissue fluid in the biological body and promoting the absorption of required nutrients in the process of bone repair. In addition, the formation of osteoid apatite in the In-vitro study, proved by FTIR and EDAX analysis, rationalized for improving the osteogenic activity. Furthermore, after 56 days of immersion in the Tris-HCl buffer solution, the weight loss rate of the bone adhesive reached up to 42.73 %, indicating that the bone adhesive had satisfactory degradation performance. Finally, in the cytotoxicity test, the survival rate of mouse precranial bone cells was found to be greater than 80 % after adding the prepared bone adhesive, demonstrating its sufficient biocompatibility.

Does afforestation increase soil water buffering? A demonstrator study on soil moisture variability in the Alpine Geroldsbach catchment, Austria

This study employed an operational monitoring network to measure soil moisture and runoff behaviour continuously in the Alpine catchment Geroldsbach-Götzens, Austria. We hypothesize that afforestation can have a positive impact on soil water buffering. To analyse the impact of soil properties and vegetation cover changes on soil water dynamics, four experimental plots were established on grassland and monitoring stations were installed in the forest. The rainfall test site is equipped with an automatic weather station to obtain meteorological observations, and weirs to measure surface runoff of natural occurring precipitation events and artificial rainfall simulations. In the plots, 200 soil moisture sensors were installed at five different depths, aimed to track and visualize infiltration and subsurface flow processes. Another twenty sensors monitored soil moisture at different afforestation stages in the forested part of the catchment. The measurements show that soils covered with young and old-growth forest have a higher and more stable soil moisture content than grassland and soils with a lack of vegetation throughout the seasons. We observed large spatial differences at plot scale, where the spatial variability of soil moisture increases with depth and is highest during convective precipitation. The initial conditions and rainfall characteristics play an important role in infiltration processes and soil water storage. Our rainfall test site demonstrated the challenges of innovative monitoring techniques and that it offers opportunities for more experiments to gather evidence-based data as input for flood models. Overall findings confirm the sponge effect of forest soils and indicate that afforestation as Nature-Based Solution reduces the temporal soil moisture variability, buffering soil water during precipitation events, which can be beneficial for runoff reduction in Alpine catchments.

Soil water dynamics and plant water uptake: Primeval mature vs. debris flow-developed half-mature subalpine fir stands in the eastern Tibetan Plateau

Natural disaster can disrupt soil structure and replace established vegetation with younger plants, altering the local hydrological processes. We used hydrogen and oxygen stable isotopes to examine soil water dynamics and plant water uptake patterns in two adjacent fir stands in the eastern Qinghai-Tibet Plateau: a primeval mature stand (MF, finer- textured soil) and a debris flow-developed half-mature stand (HMF, coarser-textured soil). Our results showed that the isotopic composition and soil gravimetric water content (SWC) in deep soil water in MF exhibited a more pronounced hysteresis pattern in response to precipitation compared to HMF, indicating lower turnover rate of soil water in MF. This was also confirmed by a smaller contribution of preferential flow to deep soil water in MF compared to HMF. The higher water storage (higher SWC values) and lower turnover rate of soil water suggest a higher soil water buffer capacity in MF. Additionally, both stands showed no significant difference in plant water sources, but plants in MF used more winter precipitation due to the lower soil water turnover rate. These differences suggest MF may be more vulnerable to water disasters, while HMF may be more susceptible to seasonal droughts under climate change. Our insights enhance understanding of hydrological processes linked to changing surface conditions and offer valuable information for managing forest water resources in mountainous regions.

Characteristic calcification behavior of five surgical aortic valve bioprostheses models: An in vitro study.

The durability of surgical aortic valve bioprostheses (SAV) is limited by the calcification of the leaflets, which results in degeneration. In clinical routine, there seems to be substantial variability in the degeneration of specific SAV models. Our study aims to establish an in vitro calcification model for prosthetic valves,characterizing the calcification behavior of different SAVs. Five commercially available SAV models (Epic™ Supra, Freestyle®, Intuity®, Perimount®, and Trifecta™) were perfused with double-distilled water and physiological buffer with a defined calcium concentration (CaCl2 = 1.5 mM) at 37°C over 32.9 million cycles in a Hi-Cycle tester which corresponds to approximately 1 patient-year (calcified group). Untreated prosthetic valves served as the negative control group (noncalcified group). Calcium titration, scanning electron microscopy (SEM), histological examination, and tissue thickness measurements were performed to evaluate noncalcified and calcified SAVs (n = 10). Treatment in the Hi-Cycle tester with calcification buffer maintained significantly higher calcium absorption of SAVs compared to the control group (p < 0.001). Additionally, hydroxyapatite crystals were found in the calcified SAV in SEM. Porcine valves rarely demonstrated punctual calcification pattern, while bovine pericardial valves presented distinct planar calcification pattern in histological examination. Further, calcification content differed significantly depending on the SAV model, with the highest calcium content in Trifecta (213 µg/cm2) and the lowest in Epic Supra (8 µg/cm2) (p < 0.001). Data from our study revealed significant differences in leaflet calcification for the various aortic valve bioprostheses models. Further studies are necessary to investigate whether these findings can mimic the clinical data of the implanted prostheses.

Landscape Planning for the Preservation of Cisadane Sub-Watershed in Situgede Area with Bioregion-based

Abstract Situ has an important role in controlling the water system by restraining the inflow hydrograph and reducing the peak discharge of the outflow. Situgede watershed, part of the Cisadane Sub-watershed consists of several Sub Catchment, namely Situ Gede, Situ Panjang, and Situ Burung, that can threaten the water system’s sustainability. Water preservation in the Situgede Sub-watershed is needed as an effort to maintain the existence and sustainability in terms of the balance and function of water resources. The availability of water resources in sufficient quantity and quality for human needs, both now and in the future must be guaranteed. This study aims to develop a landscape plan of the Situgede watershed based on Bioregion. Landscape planning is developed for each bioregion unit, especially place units, based on the direction of the small watershed zoning concept. Furthermore, based on small watershed spatial plans (zoning), landscape plans can be produced and derivative a hardscape plan, green plan, infrastructure, and utility plans. Based on bioregion-based zonation (place units) can be developed landscape planning into three zone (water management, buffer and development). Landscape plan can be prepared for the preservation of the Cisadane Sub-watershed in the Situgede Area which consists of a water body of 9.05 ha (3.92%), WWTP of 0.2 ha (0.09% ), green space in the form of research forests and greenbelts of 39.95 ha (17.29%), residential areas and public facilities of 34.48 ha (14.93%), agriculture of 131.9 ha (57.1%), agricultural buffer area of 131.9 ha (57.1%), water harvesting ponds of 4.32 ha (1.87%) in units 5-8 and 14-17, bioswale and other open space of 4 ha (1.73%). Moreover, based on the landscape plan, thematic plans can be derived, namely: hardscape plan, green plan, infrastructure, and utility plans.

Comparing Conventional and Modern Methods for The Phycocyanin Extraction from Spirullina sp

Spirulina platensis, a blue-green algae abundant in tropical regions, is rich in minerals, vitamins, fibers, and pigments, with low nucleic acid content. It has unique chromoproteins called phycobiliproteins, notably phycocyanin, used in various applications. This study aims to optimize phycocyanin extraction using different solvents (distilled water and sodium phosphate buffer pH 6.7) and methods (freeze-thaw and sonication). Spirulina platensis biomass was extracted in both solvents, then some of them was freeze for 24 and 48 hours followed by thawing overnight. The other was sonicated for 2.5 minutes, 50 Hz then soaked for 1, 2, and 3 hours. All of the samples were centrifuged at 6000 rpm for 10 minutes and the absorbance was measured using a UV-Vis spectrophotometer at wavelengths of 280, 620, and 650 nm. with freeze-thawing for 48 hours yielded the highest phycocyanin concentration (0.55%), with a yield of 11.07 and purity of 0.21. Sonication improved phycocyanin concentration, yield, and purity significantly, yielding 1.108, 25.85, and 0.26, respectively.

Enhanced recovery of R-phycoerythrin using recombination cell-assisted pressurized fluid extraction: yield, characterization, and antioxidant evaluation

The recovery of phycobiliproteins, with an emphasis on R-phycoerythrin (R-PE), from Solieria filiformis macroalgae was investigated in the current study. This is accomplished using an environmentally friendly method known as pressurized fluid extraction. Phycobiliprotein production was analyzed over time, considering four different parameters: i) solvents (ultrapure water and phosphate buffer), ii) macroalgae particle sizes, iii) stirring, and iv) pressure of 200 to 800 bar. Notably, the highest R-PE yield reached an impressive 22.53 mg/g dry biomass. The best extraction conditions were identified as a macerated structure, employing a combination of 500 bar pressure and agitation facilitated by a recombination cell. R-phycocyanin (R-PC) was also extracted with a 3.70 mg/g yield. Two distinct extracts, crude and precipitate, underwent comprehensive characterization. Extracted R-PE exhibited an α-helix structure (80.51–90.39 %), suggesting the existence of other proteins in both extracts. Three different subunits, α (15 kDa), β (21 kDa), and γ (29 kDa), were segregated under SDS-PAGE. Moreover, both extracts demonstrated antioxidant capacity, achieving a 99.55 % reduction in 2,2-diphenyl-1-picryl-hydrazil (DPPH) radicals and a 13.94 % chelation of ferrous ions. This study reports the extraction of biomolecules using the recombination cell for the first time in the literature, proving an appealing alternative for non-aggressive extraction with inherent biological activity. These findings underscore the potential applications of these extracted phycobiliproteins in various fields, including biotechnology and health.

Characterization of biosurfactants' micelles formation using fluorescence measurements: sodium taurocholate as case of study.

The evaluation of micellization parameters of surfactants that aggregate gradually, such as bile salts, is not trivial. In this work, different probes and data treatment models are tested to set up an analytical method based on fluorescence measurements to determine the critical micelle concentration (CMC) and micellization range ((C) of biosurfactants. Sodium taurocholate (NaTc) is used as example. The fluorescence intensity of five fluorophores has been monitored upon the addition of a concentrated NaTc solution in two different media: water and a biorelevant buffer (maleic buffer pH 6.5, I = 120 mM). Four different data treatment methods have been tested. The micellization process can be evaluated satisfactorily using fluorescent probes such as propranolol and tetracaine, and also monitoring directly the intrinsic fluorescence of NaTc. However, the results obtained with nonpolar probes (pyrene and naphthalene) are more complex to evaluate due to the presence of confluent processes. Although the four models tested for the data treatment are commonly used for this purpose, Carpena's method is the most appropriate as it provides the most accurate CMC and ΔC values. The micellization process is faster in a biorelevant buffer than in water. The study of the micellization of bile salts is not an evident process. After the selection of adequate probes and data treatment methods, the CMC values for NaTC in water and maleic buffer reveal that the biorelevant conditions favour micellization, which in turn may allow faster solubilization of ingested compounds.