Titration Method Research Articles

Charge-Transfer Interactions Between Antibiotics and Small Organic Acids: Spectroscopic Characterization and Computational Investigation

Six new charge-transfer complexes using ofloxacin (OFL) and sulfamethazine (SMR) as electron donors and coumaric acid (COA), cinnamic acid (CNA), and salicylic acid (SAA) as acceptors via equimolar mixture have been synthesized. The experiment used UV-vis spectroscopy to determine the formation of the complex in methanol through the presence of a new broad absorption band with a maximum wavelength in the 200-400 nm range. The molecular composition of the charge-transfer complexes was determined by the spectrophotometric titration method and found to be 1:1 (donor: acceptor). These complexes have been characterized by infrared (FTIR) and scanning electron microscopy (SEM). In the FTIR spectra, the CT complexes showed a wavelength shift compared to the reactants. The complexes exhibited various morphologies by SEM, including spherical particles, short rods, and flattened shapes. Additionally, quantum chemical calculations at the DFT/B3LYP level of theory investigated the complexes' steady-state structures, energies, and charge densities. The intermolecular binding energies was negative, indicating that the reactions of the six complexes proceeded spontaneously. There was strong van der Waals forces and hydrogen bonds between the donor and acceptor, which contributed to the complexes' strong molecular stability. The C-N and N-H groups in the donor molecule, and the -COOH group in the acceptor molecule, played key roles in the complexation process. DFT calculation results were appropriate to support our experimental results. This study highlights the molecular mechanisms of donor and acceptor action in charge-transfer interactions, providing a theoretical basis for the synthesis of antibiotic complexes and the removal of antibiotics.

PHYSICO-CHEMICAL ANALYSIS OF OGUTA LAKE WATER AND ITS EFFECT ON PHYTOPLANKTON POPULATION

Samples were collected from the three sampling stations namely; Up, Mid and Downstream respectively to investigate the effect of nutrients concentration on the phytoplankton in Oguta Lake. The methods used were electrometric, argentometric titration, phenate spectrophotometric, colorimetric, cadmium reduction and acetone extraction spectrophotometric methods were used to determine the pH of water sample, chlorides, sulphate, ammonia, phosphorus, nitrate, nitrite, chlorophyll-A, conductivity, turbidity, chemical oxygen demand, copper, colour, total dissolved solid, respectively. However, serial dilution was carried out using the spread plate or pour plate method was used to determine the microbial analysis of the sample. At the end of these researches, the Physico-chemical parameters analysed showed that Oguta Lake had total dissolved solids values of 6.50 ± 0.06mg/l, 6.50 ± 0.14 and 6.50 for upstream, mid stream and downstream respectively. The result showed there was no significance total dissolved solids difference between the various stream points (P0.05). the colour of the Lake showed significant difference ranging from 17.00 ± 1.41 and76.00 V 1.41 in upstream and downstream and the lowest value at upstream. The pH range in this study indicates that the water may be acidic (5.54-7.31). Phytoplankton assemblages obtain across the three stream points showed only three divisions and 78 species. The identified divisions and species are comprised of Eurcharyta (44), Cyanophyta (25) and Chlorophyta (9). Eurkaryta recorded 100%, 5% and 15% abundance in upstream, midstream and downstream respectively, while Cyanophyta recorded the highest abundance at downstream with 75%, Chlorophyta only was identified at the midstream and was least abundance with 23%. The phytoplankton diversity indices done showed that downstream was most diverse having the highest Shannon Weiner Index and Evenness Index of 3.631 and 1.212 respectively. In relation to physicochemical and phytoplankton abundance, the findings in this study is contradictory to some researches. They reported positive correlation of phytoplankton with phosphate and nitrate. There was negative correlation of phosphate with Eurkaryta and Chlorophyta, except for Cyanophyta that showed positive correlation with phytoplankton but not very significant. These low levels of phosphate and nitrate may be the cause of low phytoplankton levels.

Comparative estimation of ascorbic acid (Vitamin C) in Sweet-melon, Watermelon and Cucumber

This research is carried out to provide valuable information for individuals that would want to properly modify their nutrient intake. It would enable individuals to know the quantity of these fruits (Sweet melon, Watermelon and Cucumber) needed to be consumed per day to meet the Recommended Daily Allowance (RDA) of Vitamin C for healthy living. Understanding the relative content of Ascorbic acid in these fruits will help individuals plan their diets and know how to properly incorporate them in foods daily to avoid Vitamin C deficiency health problems. This study determined and compared the vitamin C content in Sweet melon, Watermelon and Cucumber. The extracted juices were analysed for ascorbic acid (Vitamin C) using Iodometric Titration method. Results obtained showed that Sweet melon contain (58.4mg/100cm³), Water melon (22.75mg/100cm³) and Cucumber (16.25mg/100cm³) concentrations of ascorbic acid. The ascorbic acid concentrations being highest in Sweet melon and lowest in Cucumber. Therefore sweet melon is the best source of Vitamin C among the three fruits analyzed. Sweet melon can be recommended for individuals suffering from vitamin C deficiency. It is recommended that nutrition and health education is needed to promote increased consumption of fruits rich in Vitamin C content to avoid diseases caused by its deficiency such as scurvy, Iron deficiency anemia, bone disease in children.

Effects of pyrolysis temperatures on the structural properties of straw biochar and its adsorption of tris-(1-chloro-2-propyl) phosphate

To investigate the effect of pyrolysis temperature on the adsorption behavior of the emerging organic pollutant tris-(1-chloro-2-propyl) phosphate (TCIPP) on biochar, corn stover was used as raw materials to prepare biochars at different pyrolysis temperatures (250, 350, 500, 700 °C) through limited oxygen carbonization. Elemental analysis, Boehm titration, FTIR, XPS, and other analytical methods were used to reveal the effect of pyrolysis temperature on the physicochemical properties of biochar and its mechanism of TCIPP adsorption. The results showed that the pyrolysis temperature had a significant impact on the physicochemical properties of biochar. As the pyrolysis temperature increases, the specific surface area of biochar rises from 3.083 m2/g to 435.573 m2/g, the pH value increases from 6.60 to 10.66, the mass percentage of C increases from 63.10 to 80.58%, and the mass percentage of O decreases from 26.42 to 9.20%. Additionally, the hydrophobicity and aromaticity of biochar also increase with rising pyrolysis temperature, while its polarity decreases. Boehm titration, FTIR, and XPS analysis showed that the total amount of functional groups on the surface of biochar decreased relatively with increasing temperature. Functional groups such as -OH, C = C/C = O, and C-O-C participated in the adsorption of TCIPP on biochar, and ester groups were produced after adsorption. The adsorption process of TCIPP on biochar fits best with the pseudo-second-order equation, indicating that the adsorption process is mainly chemical adsorption, and the main rate-controlling stage is intraparticle diffusion. The isothermal adsorption results were more in line with the Temkin model, indicating that the adsorption process of TCIPP on biochar was mainly surface adsorption. As the pyrolysis temperature increases, the maximum adsorption capacity of biochar increases from 0.8837 mg/g to 2.2574 mg/g. The adsorption process of TCIPP on biochar mainly included pore filling, hydrogen bonding, P-π interaction, hydrophobic interaction, and electrostatic attraction. Among them, pore filling, P-π interaction, and hydrophobic interaction were significantly enhanced with increasing temperature, while hydrogen bonding was relatively weakened. This study will provide a theoretical basis and technical support for the removal of TCIPP from water using biochar adsorption.

Epoxy Value Measurement of E44 Epoxy Resin by Various Chemical Titration Method

AbstractDuring the production of epoxy resins, it is crucial to control or to know the epoxy groups. It is known that epoxy value is the most important analytical index of epoxy resin physical quantity to characterize the number of epoxy groups in epoxy resin. In this paper, two ways for testing the epoxy values of E44 epoxy resin are developed based on chemical titration method: hydrochloric acid‐acetone method and perchloric acid‐tetraethylammonium bromide method. The features of different methods and the influence of approaches on epoxy value are studied systematically. At the significant level of 0.05, for hydrochloric acid‐acetone method, the confidence interval for the mean is (0.454±0.003)eq/100 g, and for perchloric acid‐tetraethylammonium bromide method, the confidence interval for the mean is (0.453±0.003)eq/100 g. It has been proved that the test results of the two methods are basically the same. And the advantages and disadvantages of the two methods have been put forward. In addition, the testing mechanism of hydrochloric acid‐acetone method and perchloric acid‐tetraethylammonium bromide method is illustrated in detail. On the basis of superiority over the two methods, a novel method for testing epoxy resin with rapid and accurate epoxy value can be envisioned.

Mild acidic charcoal: adsorption, analysis, and application.

The adsorption of glacial acetic acid over a charcoal support was investigated. The amount of adsorption was analyzed using a traditional titration method and the prepared adsorbed system was employed as a heterogeneous catalyst for organic reactions as a viable application. Different 14-aryl-14H-dibenzo[a,j]xanthenes were synthesized using mild acidic charcoal as a catalyst and yields of 88%-94% were obtained. The advantages of this method include the easy preparation of a cheaper and environmentally safe catalyst system, a simple work-up procedure, and excellent catalytic efficacy.

Cnicus Benedictus roots as a low-cost adsorbent for methylene blue dye removal from aqueous solution: kinetic and equilibrium studies

In this research, Cnicus Benedictus roots powder (CBRP) was utilized as a low-cost adsorbent for removing methylene blue (MB) as a cationic dye from aqueous solution. Characterization of CBRP by Boehm titration method, Fourier transform infrared (FT-IR) and environmental scanning electron microscope (ESEM) indicates the presence of different types of functional groups and a very rough surface filled with cavities, suitable for MB adsorption. The effect of various parameters such as CBRP dose (0.2–2 g/1L), contact time (0–180 min), initial pH (1–10), coexisting anions/cations and the initial MB concentration (100–500 mg L−1) on MB adsorption were examined, the results showed that MB uptake depends on the pH of solution, the electrostatic attraction forces, the formation of H-bonds and π–π interactions are the possible CBRP–MB interaction mechanisms. Adsorption kinetic of MB on CBRP was best represented by linear and non-linear form of the pseudo-second order model. The experimental equilibrium data were best described by linear and non-linear forms of Langmuir and Redlich–Peterson isotherm models (R 2> 0.98) with a maximum MB adsorption capacity of 85.47 mg g−1 at 25 °C, the adsorption efficiency R (%) was greater than 90 (%). MB adsorption-desorption experiments showed the reusability of CBRP for five consecutive cycles. According to the obtained results, CBRP can be used as a natural adsorbent material for cationic dyes removal from aqueous solution.

Simultaneous determination of chlorides, bromides, and fluorides in ion-conducting electrolyte

There are developed the techniques of determining the content of chlorides, bromides and fluorides at their joint presence in two types of solid electrolytes differing in matrix content: the first type contains lithium, the second one — both lithium and aluminium, simultaneously. Determination of bromides mass fraction is fulfilled using a method of iodometric titration of iodic potassium excess after bromides are oxidized until free bromine. The fluorides mass fraction is measured by the gravimetric method in the form of fluoro-chloride of lead, in this case the aluminium interfering influence is eliminated by its precipitation in the form of hydroxide after it is fused with carbonates of potassium and natrium, as well as by the method of potentiometric titration with a fluoride ion-selective electrode using the nitrate lanthanum solution. The absence of aluminium interfering influence on the result of fluorine determination is estimated by the «input – found» method. The mass fraction of chlorides is determined by calculation by difference between results of determining the sum of chlorides and bromides using the method of mercurometric titration and — separately — the bromides mass fraction. Optimal conditions of samples preparation and analysis for each of mentioned methods of analysis were selected. The limits of the relative total error of determining bromides in the range of mass fractions from 28.0 to 41.0% is ±2.1%, chlorides within the mass fraction range from 8.0 to 15.0% — ±3.6%, fluorides within the mass fraction range from 3.0 to 7.0% — ±3.4% using gravimetric method and within the mass fraction range from 5.0 to 8.0% — ±1.5% using a method of potentiometric titration. The developed techniques were certified by a metrological service of the enterprise and are used to control the chemical composition of the ion-conducting electrolyte. The techniques do not require expensive equipment, and can be used in factory laboratories.

Phytonutrient formulation using gum Arabic and Adansonia Digitata pulp: Lessons for boosting the human immune system - part 1

BackgroundThe human innate immune system (HIIs) defends the body against pathogens and relies on the energy obtained from food sources to increase its metabolic activity. AimIn this study, a new blended 3 in1 formula comprising A. senegal, A. seyal, and Adansonia digitata at a ratio of 5:3:2 was proposed as a potential aid in the management of Covid-19 patients with Metabolic Syndrome (MeT-S) disorders, with a specific focus on those presenting with impaired health. MethodsThe utilization of Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-MS) was employed to analyze 3 blended ingredient combinations, including the 3in1 formula, A. senegal, A. seyal, and A. digitata pulp, for the presence of elements by detecting the levels of moisture, ash, minerals, protein, amino acids, carbohydrates, sugars, prebiotic polysaccharides, energy, dietary fibers, and crude fibers. This advanced technique has replaced the titration method used in previous studies. ResultsThe mineral content of the blended 3in1 sample was found to be dominated by potassium (70.56±2.35), Calcium (68.54±3.12), Magnesium (16.60±4.80), Phosphorus (11.50±2.50), Sodium (31.4±4.80), Zinc (19.19±2.10), Iron (19 ± 0.14), Copper (15.12±1.81), and selenium (0.037 ± 0.005) g/100 g DW. The blended 3 in1 sample also had a higher hydroxyproline content (30.17 g/100 g and a higher total protein and carbohydrate content than the blended 2 in1 sample. Additionally, arabinose was identified as the major reducing sugar with up to 48.23 and 49.97g/100 gDW. The prebiotic polysaccharide content was 88.61±3.12g/100 gDW for the blended 3 in1 sample, which was significantly higher than that of the blended 2 in1 sample. Furthermore, the energy value of the blended 3 in1 sample was significantly higher at 350.12±5.210 kcal/100 g than the blended 2 in1 sample at 340.67±3.155 kWh. The Insoluble Dietary Fibers (IDFs) and Soluble Dietary Fibers (SDFs) of the blended 3 in1 sample were 12.6±2.10 g/100 gDW and 87±2.124 g/100 g DW, respectively, which were significantly higher than those of the blended 2 in1 sample. ConclusionThe discovery of distinct molecular compositions of A. senegal and A. seyal when combined with Adansonia Digitata Pulp (ADLP) in the 3 in1 blend demonstrated enhanced HIIs among Covid-19 patients with compromised MeT-S disorders. This may be considered a valuable natural antiviral agent for the treatment of such individuals.

A Novel Rhodamine‐Tetraphenylporphyrin Fluorescence Probe for Imaging Mercury In Vitro and In Vivo

ABSTRACTA highly selective fluorescent sensor Por‐RBO for determination of Hg2+ was designed and synthesized with Rhodamine B and Tetraphenylporphyrin. The sensor can determine the Hg2+ of a solution within the pH 5.0–8.0, free from interference of other metal ions. When detected in buffer solution, the fluorescence was the strongest when five times the concentration of Hg2+ ion was added. Calculated by fluorescence titration method, the detection limit of sensor Por‐RBO for Hg2+ ion was as low as 0.12 μmol/L. The geometries of Por‐RBO and Por‐RBO‐Hg2+ were optimized at the B3LYP/6‐31G** level by density functional theory. The charge distribution, orbital interactions, and bonding characteristics were analyzed and compared in detail to discuss the recognition mechanism and structure–fluorescence property relationships. The results of cell fluorescence imaging and CCK‐8 experiments indicate that the sensor Por‐RBO exhibits lower cytotoxicity. Por‐RBO can be used for fluorescence distribution imaging of Hg2+ in living cells.

Synthesis, crystal structure, Hirshfeld surface analysis, DFT computations and protein binding efficiency of a 1-D Ni(II) chain derived from a tridentate Schiff base ligand

A new Ni(II)-azido 1-D coordination polymer, [Ni2L2(μ1,1-N3)(μ1,3-N3)]n, was obtained through reaction of 1-[(3-dimethylamino-propylimino)-methyl]-naphthalen-2-ol (HL) and the perchlorate salt of nickel(II) in the presence of pseudohalide azide. X-ray crystallography and spectroscopic experiments (IR and UV-Vis) were used to describe this coordination polymer (CP). Single crystal X-ray studies revealed that the CP is a one-dimensional chain of Ni(II) in which the neighboring dimeric units (triply bridged by di-μ2-phenoxidoand µ1,1-N3) are further connected by μ1,3-azido bridges in a zig-zag fashion. The cooperative participation of N···H hydrogen bonding, π···π stacking and C-H···π interactions occur during crystal packing. A 2-D supramolecular architecture with star-shaped voids results from additional C–H···π stacking interactions. Hirshfeld surface analysis was used to look at the intermolecular interactions. DFT studies were carried out to calculate the HOMO-LUMO band gap of the ligand as well as the coordination polymer. Interaction of the CP with bovine serum albumin (BSA) protein was investigated spectroscopically by absorption and fluorescence titration methods. The result showed that the CP could quench the intrinsic fluorescence of BSA. Fluorescence resonance energy transfer (FRET) studies revealed that energy transfer takes place from BSA to the CP. Cyclic voltammetry of the CP indicated an irreversible cathodic redox couple assigned to Ni(II)/Ni(I).

Characterization of chemical properties of fish-flavoured spicy tamarind cube

Fish-flavoured spicy tamarind cube is categorized as a type of bouillon cube. It is a processed food that has been developed and benefits the consumers due to low cost, being ready to use, reduced cooking time and giving intense flavour to the cooking dish. Food processing improves the stability, safety, taste and makes the food healthier. While there are various advantages to processing, the chemical food characteristics might be adversely affected. The study aimed to evaluate the amount of chemical composition, macromolecule, phytochemical content, peroxide value and antioxidant activity present in the fish-flavoured spicy tamarind cube. The analysis was performed using a different methodology. The content of mineral and ascorbic acid of the cube was evaluated by using scanning electron microscopy-energy dispersive X-ray (SEM-EDX) and titration methods respectively. Carbohydrate was estimated by difference using equation and protein by micro Kjeldahl method. For both phytochemical compounds, total phenolic and flavonoid are measured spectrophotometrically in this study. In addition, peroxide value was determined by titration method and antioxidant activity was assayed using 2,2- diphenyl-1-picrylhydrazyl (DPPH) free radical. The result showed the cube contained 2.12% sodium, 1.22% copper and 0.43% potassium while the ascorbic acid value was 66.00 mg/100 g. The macromolecule content recorded was 40.15 g/100 g for carbohydrates and 7.54 g/100 g for protein. The cube had 10.77 mg GAE/g and 21.72 mg QE/g for total phenolic and flavonoid respectively. The peroxide value of the cube was 9.52 meq/kg and classified in a moderate oxidation state. Furthermore, the half-maximal inhibitory concentration (IC50) for antioxidant activity analysed was 89.04 µg/mL which means the cube shows intermediate antioxidant activity. Based on the result, the cube is safe to consume and can provide health benefits to consumers.

Temperature Changes in Luminescence of Mixed Complexes of Terbium and Samarium with Organic Ligands Based on 2,2-bipyridyldicarboxamides

Solutions in acetonitrile of three mixed complexes of rare earth elements (terbium and samarium) with organic ligands with various pyridine substituents were studied in this work. The ratios of ligands and metals in the resulting complexes were determined, and the stability constants of samarium complexes were calculated using the spectrophotometric titration method. Measurements of absorption, emission and excitation spectra of luminescence, luminescence kinetics of solutions of mixed complexes of rare earth elements with an excess of metal relative to the ligand were carried out at various temperatures in the range 298–328 K. An increase of luminescence intensity of a samarium ion in complex upon heating has been discovered for the first time. The dependences of the luminescence quantum yield and lifetime of mixed complexes on temperature were obtained. A thermometric parameter — the ratio of the integral luminescence intensities of samarium and terbium ions — was proposed, and the temperature sensitivity coefficient of this parameter was determined for different complexes.

Biochemical composition of three Opuntia species O. humifusa, O. phaeacantha, O. engelmannii var. lidheimeri. Prospects of their utilization

Relevance. Opuntia distinguished by high adaptability is widespread in many countries of the world. Tolerance to water deficiency and high biological activity provide prospects of its cultivation for food and pharmaceutical industry. In Russia Opuntia is grown in the Crimea, Caucasus, Donbass, Astrakhan region and even in the Central Russia. Evaluation of the Opuntia cultivation efficiency in the Crimea for various utilization supposes the importance of its biochemical characteristics which variability greatly depends on the place of habitat. Materials and Methods. Total antioxidant activity and titratable acidity were determined using titration methods, polyphenol content –using spectrophotometric method, monosaccharide and total sugar concentrations were assessed via reaction with ferricyanide, mucilage levels were determined gravimetrically.Results. Investigation of cladode, inflorescence and fruit biochemical parameters of three Opuntia species: O. humifusa, O. phaeacantha, O. engelmannii, – gathered at the Southern and South-Eastern part of the Crimean peninsular revealed wide variability of fruit mucilage (4.3-16.56% d.w.), sugar and total antioxidant activity. Polyphenol content decreased according to: inflorescence (18.4-21.0) > fruit (11.7-18) > cladodes (10.2-20.0). Fruit monosaccharide content reached (6.2-31) % while in cladodes these values were in the range of 8.1-16.0%. Total sugar content was equal to 32.6-95% in fruit and 15.5-29.7% in cladodes. Concentration of selenium as a natural antioxidant was higher in the cladodes (102-176 µg/kg d.w.) than in fruit (46.8-72 µg/kg d.w.). The highest levels of the total antioxidant activity and titratable acidity were registered in O. engelmannii while the highest sugar, mucilage and taste index were typical for O. humifusa. Nevertheless, O. humifusa was characterized by the lowest fruit mass (6.0-6.3 g) contrary to O. engelmannii (36-40 g). The results suppose prospects of fruit, cladode and inflorescence utilization in food industry, cosmetics and pharmacology with the preference to O. humifusa.

Using QI to develop a sustainable method for titrating taxane infusions to reduce hypersensitivity reactions.

To develop a sustainable three-step method for titrating first and second taxane exposures through integration of best practices in patient and environmental safety; and to evaluate the impact on immediate hypersensitivity rates. A quality improvement study was initiated at a large, NCI-designated comprehensive cancer center in the U.S. to determine a sustainable method of slow, upward titration for reducing taxane-related hypersensitivity reactions. Multidisciplinary collaboration led to the incorporation of best practices for safe preparation and administration of high risk, hazardous drugs. Retrospective data from the electronic health records of 690 patients who received 1221 taxane doses were analyzed. Non-titrated infusions were compared with infusions titrated using a method initially tested for efficacy; and infusions titrated using a method revised for greater compliance with safety standards. Two-sided Fisher's exact tests at a 0.1 level of significance were used to detect differences in the rate of HSR between the three groups. A method of taxane titration that incorporated standardized, preprogrammed infusion rates and tubing primed with inert IV fluid showed a significant reduction in HSR incidence in comparison to non-titrated infusions (6% v. 19%, P = 0.001) and a similar decrease in the rate of HSR (6%) to the initial method previously studied (7%) (P = 0.659) which was not sustainable due to patient and environmental safety concerns. A three-step titration method using standardized, preprogrammed infusion rates and tubing primed with inert IV fluid reduced taxane-related HSRs and was adopted as sustainable practice in ambulatory cancer care.

Facile photometric quantification of aldehyde content in oxidized starches using 2-aminobenzamide oxime as an aldehyde selective reagent

AbstractThe oxidation of starch to aldehyde starch or dialdehyde starch introduces aldehyde groups to the starch core structure. This functionalization enables a wide range of further derivatization, e.g., oxidation to the corresponding carboxylic acid or functionalization to the corresponding amine via imine formation and reduction, which can be used for cross-linking. Herein, we report a novel method for efficiently quantifying these aldehyde groups based on the selective adduct formation of 2-aminobenzamide oxime (ABAO) and aldehydes. We initially implemented this photometric assay for C6-oxidized aldehyde starch using a plate reader, enabling parallel analysis of multiple samples in a fraction of the time and consistent with the conventional titration methods. Complementing this stream-lined analytical approach, we present an abbreviated workflow for faster downstream processing of reaction samples toward analysis. All of this was performed at a very small scale, cutting costs for (expensive) reagents and solvents, as well as drastically reducing working time. Finally, we also demonstrate our assay's applicability for quantifying the two aldehyde groups formed in dialdehyde starch derived from NaIO4 oxidation. Graphical abstract

مقارنة محتوى فيتامين C في بعض عينات الفواكه الطازجة والمجمدة

The concentrations of Vitamin C, also known as L-ascorbic acid, in eleven different types of fresh and frozen fruits were determined by titration method. The effects of some conditions such as time of freezing on the Vitamin C contents were studied. Samples were collected from farms close to Janzour overall seasons. Each sample or a part of it was squeezed to get juice and centrifuged; the volume and the weight of the supernatant liquid were taken. The estimation of vitamin C concentrations were done for fresh samples, after 12, 24, 48 and 72 hours and frozen samples after 1, 2, 3 and 4 weeks. From obtained results, the concentrations of vitamin C were decreased with increasing time of experiments for fresh and frozen samples with statistically significant deference. The highest concentration was found in blood oranges and lowest concentration noticed with apple for fresh and frozen samples. Meanwhile, the concentration of vitamin C was higher in frozen sample than fresh sample without significant differences. In conclusion, the freezing method for limited time (month for example) is the best way to maintain the concentration of vitamin C because it works to inhibit the activity of oxidative enzymes and break down the vitamin C. Keywords: Vitamin C, Frozen fruits; Fresh fruits; titrimetric method; L-ascorbic acid

Eco-Friendly Synthesis of Cerium Nanoparticles Using Spirulina platensis: Assessing Antibacterial and Anti-inflammatory Efficacy.

Spirulina platensis, a type of cyanobacterium (blue-green algae), is well known for its rich abundant nutritional profile and bioactive compounds, which contribute to various biological functions within the human body. The application of nanotechnology toSpirulina has the potential to further enhance its biological activity in biomedical assays. This study aimed to utilize Spirulina platensisfor the green synthesis of cerium oxide nanoparticles (CeO-NPs) and evaluate their physiochemical properties. The research will assess the antibacterial and anti-inflammatory efficacy of the synthesized nanoparticles and explore the underlying mechanisms of action. Spirulinaplatensis-mediatedcerium oxide nanoparticlesare synthesized by thegreen synthesis (titration method). The biosynthesized CeO-NPs are characterized by using techniques such as UV-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX). Antibacterial activity was carried out by the agar-well diffusion method and anti-inflammatory activity was carried out by the albumin denaturation method. The green synthesis of cerium oxide nanoparticles (CeO-NPs) using Spirulina, a sustainable and eco-friendly method has potential application in antibacterial and anti-inflammatory therapies. This study focuses on the green synthesis of CeO-NPs and characterizes them by using UV-Vis, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), SEM, and EDX. The UV-vis analysis confirmed the presence of CeO-NPs at a wavelength of 320 nm. FT-IR reveals four functional groups, such as C-O, N-O, and C=Cstretches. XRD analysis showed higher crystallineand less amorphous content. SEM and EDX spectra were utilized to confirm the morphology (agglomerated square shape) and the elemental composition [Ce, O, C]in the CeO-NPs. The antibacterial activity was evaluated against multidrug-resistant (MDR) clinical strains and the anti-inflammatory activity revealed significant activity in a dose-dependent manner. This study concluded that Spirulina-mediated CeO-NPs have potential as a drug in biomedical assays. Further in vitro and in vivo analysis is required to fully confirm their viability as a potential drug.

Development and validation of a droplet digital PCR method for quantifying lentiviral vector infectious titer

Lentiviruses, with their high transduction efficiency and gene expression levels, are widely used as gene delivery vectors in the development of chimeric antigen receptor T cells (CAR-T) and other genetically modified cell therapies. Accurate determination of the lentiviral vector infectious titer is essential to ensure effective transduction and product consistency. In this study, we developed an efficient method for lentiviral vector titration based on digital droplet polymerase chain reaction (ddPCR) technology, enabling absolute quantification of the target gene. Benzonase treatment of non-transduced plasmids substantially shortened the experimental period, reducing cell culture duration from 10-14 days–3 days. The method was rigorously validated by assessing specificity, working range, limit of quantification, precision, accuracy, and robustness. This study demonstrates the feasibility of combining enzymatic digestion with ddPCR to quantify lentiviral vector infectious titer and provides a detailed and readily adaptable methodology for the scientific community.

Potential Fermentation of Sweet Potato Pickle (Ipomoea batatas L.) with Lactobacillus plantarum B1765 in the Production of Short Chain Fatty Acids

Short-chain fatty acid (SCFA) is the final metabolic product of inulin that can provide various health benefits. In this study, the effect of fermentation duration of sweet potato pickle using Lactobacillus plantarum B1765 starter culture in the production of SCFA was studied, as well as its relationship with total Lactic Acid Bacteria (LAB), pH, and Total Titratable Acid (TTA). Fermentation was carried out with the addition of starter culture as much as 10% (v/v) at 37ºC for 4, 8, 12, 24, and 0 hours which was used as a control. The number of LAB was measured using the Total Plate Count (TPC) method, pH value was measured with a pH meter, TTA was measured using the acid-alkalimetric titration method, and SCFA was measured using an HPLC instrument with 0.1% H3PO4 eluent and 25% acetonitrile. Fermentation duration affects LAB growth, TTA, SCFA, and pH. The results showed that total LAB growth was optimal at 8 hours fermentation time at 2.81×108 CFU/mL, which increased by 2 log cycles from the initial fermentation time of 0 hours. Still, the pH decreased until it reached 3.23 ± 0.20, and TTA increased to 0,56 ± 0.02% until the end of fermentation at 24 hours. SCFA also increased until the end of fermentation at 24 hours, where acetic acid levels showed the highest levels (6.85 ± 0.30 mg/mL), followed by propionic acid (5.04 ± 0.20 mg/mL) and butyric acid (2.14 ± 0.10 mg/mL). Sweet potato pickles fermented with L. plantarum B1765 starter culture have met the SNI 01-3784-1995 standard and have the potential to be developed as a functional food source of SCFA, which has many health benefits.