L-ascorbic Acid Concentration Research Articles

Na2Ti3O7@RF@Ag Heterostructures as Efficient Substrates for SERS and Photocatalytic Applications.

A multi-step procedure was effectively employed to synthesize innovative three-dimensional (3D) heterostructures encompassing sodium titanate (Na2Ti3O7) nanowire cores, an intermediate resorcinol-formaldehyde (RF) layer, and outer silver (Ag) nanoparticle sheaths, referred to as Na2Ti3O7@RF@Ag heterostructures. Initially, a one-step hydrothermal technique facilitated the direct growth of single-crystal Na2Ti3O7 nanowires onto a flexible Ti foil. Subsequently, a two-step wet chemical process facilitated the sequential deposition of an RF layer and Ag nanoparticles onto the Na2Ti3O7 nanowires at a low reaction temperature. Optimal concentrations of silver nitrate and L-ascorbic acid can lead to the cultivation of Na2Ti3O7@RF@Ag heterostructures exhibiting heightened surface-enhanced Raman scattering (SERS), which is particularly beneficial for the detection of rhodamine B (RhB) molecules. This phenomenon can be ascribed to the distinctive geometry of the Na2Ti3O7@RF@Ag heterostructures, which offer an increased number of hot spots and surface-active sites, thereby showcasing notable SERS enhancement, commendable reproducibility, and enduring stability over the long term. Furthermore, the Na2Ti3O7@RF@Ag heterostructures demonstrate remarkable follow-up as first-order chemical kinetic and recyclable photocatalysts for the photodecomposition of an RhB solution under UV light irradiation. This result can be attributed to the enhanced inhibition of electron-hole pair recombination and increased surface-active sites.

Effects of l-ascorbic acid on growth, non-specific immunity, antioxidant capacity, and intestinal and hepatopancreatic histology of red swamp crayfish, Procambarus clarkii

This study investigated the dietary effects of coated l-ascorbic acid (LA) on growth, feed utilization, survival, serum biochemical indices, immunity, antioxidant capacity, and intestinal and hepatopancreatic histology of the pre-adult red swamp crayfish. Four isoproteinous and isolipidic diets were formulated to contain several LA levels as 0, 1300, 1600, and 1900 mg/kg and designated as control (LA0), LA13, LA16, and LA19, respectively. However, the analyzed LA concentrations in diets were 0.00, 199.57, 360.45, and 487.50 mg/kg in LA0, LA13, LA16, and LA19, respectively. Triplicate treatments of crayfish (21.60 ± 0.14 g) were fed the test diets and reared in fiberglass tanks with a density of 20 individuals per each for eight weeks. Results revealed that all LA treatments had significantly enhanced growth performance compared to the control. Of interest, the LA16 treatment recorded the highest final tank biomass, biomass gain, total feed intake, condition factor, and muscle yield among the other treatments. The tank feed conversion ratio was significantly decreased in LA treatments compared to the control. Moreover, dietary LA16 and LA19 had significantly higher survival rates (93.3%) compared to (85.0%) in the LA0 group. All dietary doses of LA significantly increased serum parameters (total protein, albumin, globulin, lysozyme activity) and respiratory burst activity compared to the LA0 treatment. Dietary LA16 significantly boosted the hepatopancreatic antioxidant capacity, manifested by decreased malondialdehyde concentrations, increased catalase, superoxide dismutase, and glutathione peroxidase enzyme activities, and reduced glutathione content compared to the LA-free diet. A normal histoarchitecture of the hepatopancreatic tubules was found in all LA treatments except with some minor degenerative changes in the tubular lumen, and hepatopancreatic cells associated with enlarged nuclei were found in the LA19. However, normal intestinal histoarchitecture was found in all treatments with no recorded intestinal lesions. Of interest, the polynomial regression performed on the analyzed LA concentrations suggested that 380 mg/kg would be suitable to provide maximal biomass gain for pre-adult crayfish. In conclusion, results revealed that coated LA could enhance the growth, immunity, and antioxidant capacity of pre-adult red swamp crayfish, suggesting its potential as a functional and necessary micronutrient for crayfish diets.

Ultralight, superhydrophobic and fire-resistant nitrogen-doped graphene aerogel for oil/water separation

The simultaneous achievement of graphene aerogels with low density, high adsorption capacity and selectivity, as well as high mechanical strength, holds great significance but remains a challenging task. By adjusting the concentration and ratio of graphene oxide, dopamine and L-ascorbic acid, the hydrogel without obvious volume shrinkage and stability was synthesized by hydrothermal reaction at low temperature, after freeze-drying and calcination, nitrogen doped graphene aerogel (NGA) with ultralight, superhydrophobic, superoleophilic, fire-resistant, and compressible/recoverable were obtained. The density of NGA is only about 1.9 mg/cm3, and the water and oil contact angles in air are 153.3° and 0°, respectively. Given the aforementioned beneficial features, NGA can efficiently select and adsorb multifarious of oils and organic solvents in oil/water mixtures so as to achieve oil/water separation. Remarkably, NGA exhibits an impressive adsorption capacity of up to 150–305 times its own weight, and it also possesses excellent adsorption recyclability. Therefore, NGA has great potential in the treatment of oil pollution in the water environment.

Effects of the In ovo Administration of L-Ascorbic Acid on Tissue L-Ascorbic Acid Concentrations, Systemic Inflammation, and Tracheal Histomorphology of Ross 708 Broilers Subjected to Elevated Levels of Atmospheric Ammonia

The effects of in ovo injection of L-ascorbic acid (L-AA) on tissue L-AA concentrations, systemic inflammation, plasma mineral concentrations, and tracheal histomorphology of Ross 708 broilers subjected to elevated atmospheric ammonia (NH3) levels after hatch were investigated. The four in ovo treatments included non-injected (control), saline-injected (control), or saline containing 12 or 25 mg of L-AA. The in ovo treatments were applied at 17 days of incubation by injecting a 100 μL volume of each pre-specified treatment into the amnion. At hatch, 12 male chicks were randomly allocated to each of the 12 replicate battery cages belonging to each treatment group. The cages were arranged in a randomized complete block design within a common room. All birds were exposed to 50 ppm of NH3 at 35 days of posthatch age (doa), and the concentration of NH3 in the room was recorded every 20 s. At 0, 7, 14, 21, and 28 doa, one bird from each cage was arbitrarily selected and euthanized for determinations of liver and eye L-AA concentrations at 0, 7, 14, 21, 28 doa; plasma nitric oxide concentrations at 0, 14, 21, and 28 doa; and plasma calcium and trace mineral concentrations at 0 and 21 doa. Tracheal histomorphology evaluations were performed at 0, 21, and 28 doa. There were no significant treatment differences for plasma nitric oxide and mineral concentrations, and for liver and eye L-AA concentrations at each sampling timepoint. In ovo injection of either 12 or 25 mg of L-AA decreased tracheal attenuation incidence at 0 doa compared to the non-injected or saline-injected control groups. Furthermore, the percentage of mild tracheal inflammation scores was lower at 28 doa in response to the in ovo injection of 12 mg of L-AA compared to the non-injected or saline-injected control groups. These results indicate that in ovo injection of 12 mg of L-AA reduces tracheal inflammation in broilers subjected to elevated atmospheric NH3.

An Advanced Alkaline Al-Air Fuel Cell Using l-Ascorbic Acid Interface Layer upon Al Anode via Gradient Anti-corrosion

Al metal is considered as an excellent anode material for metal-air fuel cells thanks to the advantages in terms of capacity and energy density. However, the anodic parasitic corrosion has brought great obstacles to the performance breakthrough of Al-air fuel cells. Herein, we innovatively develop an advanced organic interface layer on an Al anode via gradient anti-corrosion, wherein low-cost, nontoxic, and high-ionized l-ascorbic acid is used to modify two basic research systems, 4 M KOH and 4 M KOH electrolyte containing 0.3 M ZnO. The results show that the relative anti-corrosion efficiency of Al and Zn@Al anodes can be gradually enhanced with the increase of l-ascorbic acid concentration. The optimal modification concentration of l-ascorbic acid is 0.35 M. The capacity and anode utilization of the cell increase to 479.50 mAh/g and 16.09% at 20 mA/cm2 after the l-ascorbic acid modification of 4 M KOH, respectively, while an excellent capacity of 2208.39 mAh/g and an anode utilization of 74.09% can be achieved for the cell using an l-ascorbic acid interface layer on a Zn@Al anode at the same current density. The density functional theory reveals that the groups of O–C═C–O and C═O in the layer molecules tend to accept the electrons provided by the Al and Zn@Al surfaces and release more adsorption energy than free H2O. l-ascorbic acid molecules are adsorbed on the anode surface as a stable interface layer, achieving Al self-corrosion inhibition and promoting the sustainable development of Al-air fuel cells.

Kinetics of L-ascorbic acid degradation and non-enzymatic browning development in hot-compressed water.

The effect of reaction conditions, which comprised the reaction temperature (150-190°C), processing time (0.50, 0.75, 1.00, 1.25, 1.50, 2.00, and 2.50 h), pH (5.0, 7.0, and 9.5), and concentration (0.03-0.07 mol/L) of L-ascorbic acid (ASA), on the degradation of ASA was investigated in hot-compressed water (HCW). The degradation kinetics of ASA and generation kinetics of browning products (BPs) were studied. The results showed that ASA degradation conformed to the pseudo-first-order kinetics, and the formation of BPs was closely related to the concentration of H3O+ in HCW. The acidic condition (pH = 5.0) and lower concentration of ASA (0.03 mol/L) were more favorable for ASA degradation. In HCW, the average apparent activation energy (Ea) of ASA was 15.77, 31.70, and 47.53 kJ/mol at pH 5.0, 7.0, and 9.5, respectively. The possible degradation mechanisms of ASA and the generation of BPs in HCW were proposed based on the experimental results.

Temperature Correction of Spectra to Improve Solute Concentration Monitoring by In Situ Ultraviolet and Mid-Infrared Spectrometries toward Isothermal Local Model Performance.

Changes in temperature can significantly affect spectroscopic-based methods for in situ monitoring of processes. As varying temperature is inherent to many processes, associated temperature effects on spectra are unavoidable, which can hinder solute concentration determination. Ultraviolet (UV) and mid-infrared (IR) data were acquired for l-ascorbic acid (LAA) in MeCN/H2O (80:20 w/w) at different concentrations and temperatures. For both techniques, global partial least squares (PLS) models for prediction of LAA concentration constructed without preprocessing of the spectra required a high number of latent variables to account for the effects of temperature on the spectra (root mean square error of cross validation (RMSECV) of 0.18 and 0.16 g/100 g solvent, for UV and IR datasets, respectively). The PLS models constructed on the first derivative spectra required fewer latent variables, yielding variable results in accuracy (RMSECV of 0.23 and 0.06 g/100 g solvent, respectively). Corresponding isothermal local models constructed indicated improved model performance that required fewer latent variables in the absence of temperature effects (RMSECV of 0.01 and 0.04 g/100 g solvent, respectively). Temperature correction of the spectral data via loading space standardization (LSS) enabled the construction of global models using the same number of latent variables as the corresponding local model, which exhibited comparable model performance (RMSECV of 0.06 and 0.04 g/100 g solvent, respectively). The additional chemometric effort required for LSS is justified if prediction of solute concentration is required for in situ monitoring and control of cooling crystallization with an accuracy and precision approaching that attainable using an isothermal local model. However, the model performance with minimal preprocessing may be sufficient, for example, in the early phase development of a cooling crystallization process, where high accuracy is not always required. UV and IR spectrometries were used to determine solubility diagrams for LAA in MeCN/H2O (80:20 w/w), which were found to be accurate compared to those obtained using the traditional techniques of transmittance and gravimetric measurement. For both UV and IR spectrometries, solubility values obtained from models with LSS temperature correction were in better agreement with those determined gravimetrically. In this first example of the application of LSS to UV spectra, significant improvement in the predicted solute concentration is achieved with the additional chemometric effort. There is no extra experimental burden associated with the use of LSS if a structured approach is employed to acquire calibration data that account for both temperature and concentration.

Effects of the In Ovo and Dietary Supplementation of L-Ascorbic Acid on the Growth Performance, Inflammatory Response, and Eye L-Ascorbic Acid Concentrations in Ross 708 Broiler Chickens.

Simple SummaryL-ascorbic acid (L-AA), known as vitamin C, is involved in several metabolic process, including bone formation, antioxidant activity, and inflammatory response. It is well documented that the antioxidant capacity and immunity of broilers are enhanced in response to the dietary or in ovo administration of L-AA. The aim of the current study was to determine the effects the in ovo or dietary administration of L-AA on the post hatch performance, plasma nitric oxide, and eye L-AA concentrations of Ross 708 broilers. At 17 days of incubation, the following treatments were administered: non-injected or sham-injected (100 μL of saline) controls, or the injection of either 12 or 25 mg of L-AA suspended in 100 μL of saline. In addition, chicks were fed a commercial diet with or without 200 mg/kg of supplemental L-AA. The results of the current study revealed that the eye concentrations of L-AA were higher in males in comparison to females. Additionally, 12 mg of L-AA decreased plasma nitric oxide levels in 14-day-old male broilers in comparison to all the other in ovo injection treatment groups. Compared to a commercial diet, dietary L-AA lowered feed conversion ratio during the second week of post hatch growth. In conclusion, the in ovo administration of L-AA was more effective in reducing inflammatory response, whereas the dietary source had a greater impact on the live performance of broilers. Further research is needed to determine the aforementioned effects throughout the entire growing phase.Effects of the dietary and in ovo administration of L-ascorbic acid (L-AA) on the performance, plasma nitric oxide, and eye L-AA concentrations of Ross 708 broilers were investigated. At 17 days of incubation, live embryonated hatching eggs were randomly assigned to a non-injected or sham-injected (100 μL of saline) control group, or a group injected with either 12 or 25 mg of L-AA suspended in 100 μL of saline. Chicks received a commercial diet with or without 200 mg/kg of supplemental L-AA and were randomly assigned to each of 6 replicate floor pens in each in ovo injection-dietary treatment combination. Weekly live performance variables through 14 days of post hatch age (doa) and the eye weights in both sexes at 0, 7, and 14 doa were determined. At 0 and 14 doa, plasma nitric oxide levels and eye L-AA concentrations of one bird of each sex in each pen were determined. Dietary supplemental L-AA decreased feed intake and growth between 0 and 7 doa, but from 8 to 14 doa; all birds fed supplemental L-AA had a lower feed conversion ratio. At 14 doa, male chicks had higher eye L-AA concentrations and lower plasma nitric oxide levels when treated in ovo with 12 mg of L-AA. In conclusion, dietary L-AA may be used to improve feed conversion in the second week of broiler post hatch growth. However, the in ovo administration of 12 mg of L-AA can increase male eye L-AA concentrations and is effective in reducing their general inflammatory response.

Comparison of the Yield of Different Rice Varieties Treated with l-Ascorbic Acid on Site-Specific Saline Soil

We conducted a comparative study of the effect of vitamin C (l-ascorbic acid) treatment on the yield of selected rice varieties grown in site-specific saline soil; the study area was Paluh Merbau, which is situated on the east coast of North Sumatra and has a salinity of 5.9 dS/m. Salinity causes osmotic, salt-specific, and oxidative stress, which negatively affects crop yields. The aim of this study was to compare the effects of l-ascorbic acid treatment on the yield parameters of eight varieties of rice grown on saline soil. This study was based on a randomized block design with two factors. The first factor was the rice variety (Ciherang, IR 64, Lambur, Batanghari, Banyuasin, IR 42, Inpara 10, and Margasari), and the second factor was the concentration of l-ascorbic acid (0, 500, 1,000, or 1,500 mg/L). The number of empty grains per panicles, grain weight per clump, and number of filled grains per panicles increased as the concentration of l-ascorbic acid increased. l-Ascorbic acid at a concentration of 1,500 mg/L exhibited the best results, and the grain weight of Banyuasin and Batanghari varieties was 33.22 and 30.18 g, respectively; however, there was no significant difference in grain weight between the varieties. Batanghari and Ciherang were the most salt-tolerant genotypes, with a high ability to produce high number of filled grains compared to other varieties. l-Ascorbic acid treatment can promote the yields of rice varieties grown under salinity stress.

Effect of Ascorbic Acid Concentration on the Stability of Tartrate-Capped Silver Nanoparticles

In this work, tartrate-capped silver nanoparticles (AgNPs) by reducing Ag+ ions into Ag0 using L-ascorbic acid and capping disodium tartrate have been prepared. The reaction was carried out at room temperature in an alkaline medium of pH 11 to obtain a rapid and one-step green synthesis method. The effect of L-ascorbic acid concentration on the synthesis preparation was studied to investigate their impact on the particle size, morphology, and stability of the AgNPs. The obtained tartrate capped AgNPs have SPR absorbance in 390–410 nm. They have a spherical shape, as confirmed by TEM. Increasing L-ascorbic acid concentrations from 25 mM to 100 and 200 mM leads to the 27, 17, and 11 nm particle size distributions. They give the zeta potential of –33.5, –20.8, and –21.3, respectively. After a week, the decreasing absorbance peaks were 0.151, 0.0105, and 0.336 a.u. The optimum L-ascorbic acid concentration was obtained at 100 mM, indicated by the smallest FWHM point. Thus, we may conclude that lower or higher levels of reducing agents resulted in low stability. Therefore, controlling L-ascorbic acid concentration is an important parameter. A sufficient concentration and an appropriate capping agent can produce good nanoparticle stability essential for further application.

Effects of the In Ovo Injection of L-Ascorbic Acid on Broiler Hatching Performance.

Simple SummaryPrevious studies have shown positive effects of the use of supplementary L-ascorbic acid (L-AA) to mitigate various stressors such as heat and ammonia exposure in the broiler industry. The aim of the current study was to determine the effects of L-AA administrated by in ovo injection on various hatch variables and the embryonic serum L-AA concentrations of Ross 708 broilers. At 18 days of incubation (doi), the following four treatment groups: non-injected control, saline-injected control, and saline containing either 12 or 25 mg of L-AA were administrated. An automated multi-egg injector accurately delivered 100 μL solution volumes into the amnion. The in ovo injection of high levels of L-AA (12 and 25 mg) did not affect hatchability, but 12 mg of L-AA in saline and saline alone resulted in a reduction in embryonic mortality. Additionally, serum L-AA did not differ between the in ovo injected treatments at any time period; however, the serum L-AA concentration was numerically higher in males as compared to female hatchlings. In conclusion, the automated in ovo injection of high levels of L-AA may not be detrimental to hatchling quality but may promote embryonic livability.Effects of the in ovo injection of various concentrations of L-ascorbic acid (L-AA) on the hatchability and retention levels of L-AA in the serum of broiler embryos were investigated. A total of 960 Ross 708 broilers hatching eggs were randomly divided into four treatment groups: non-injected control, saline-injected control, and saline containing either 12 or 25 mg of L-AA. At 18 days of incubation (doi), injected eggs received a 100 μL volume of sterile saline (0.85%) alone or containing one of the two L-AA levels. Percentage egg weight loss was also determined from 0 to 12 and 12 to 18 doi. Hatch residue analysis was conducted after candling to determine the staging of embryo mortality. At approximately 21 doi, hatchability of live embryonated eggs (HI) and hatchling body weight (BW) were determined. Blood samples were taken at 6 and 24 h after L-AA in ovo injection to determine serum L-AA concentrations. Serum L-AA concentrations, HI, and hatchling BW did not differ among all treatment groups. However, chicks in the non-injected group had a higher (p = 0.05) embryonic mortality at hatch in comparison to those in the 12 mg of L-AA in saline and saline alone treatment groups. These results suggest that the in ovo injection of high levels of L-AA (12 and 25 mg) does not negatively affect HI or serum concentrations of L-AA but has the potential to promote embryonic livability. Further research is needed to determine the retention time of L-AA in the other tissues of broilers, including the cornea of the eye, in response to different levels of supplemental L-AA.

Quality of Different Papaya Cultivars Grown in the Greenhouse throughout the Year in Subtropical Regions

Harvest time is one of the factors affecting postharvest fruit quality. Under the subtropical condition, greenhouse cultivation allows a year-round harvest. However, the crop should meet the quality and the marketing criteria for overall customer satisfaction. This study aims to determine the impact of the harvest season on the quality characteristics of papaya fruit. For this purpose, two different cultivars (Sel-42 and Tainung) were grown in the greenhouse and harvested in the winter, the summer, the spring, and the autumn of two years. Sampling was carried out at the same visual maturity stage at each season. The two cultivars had soft fruit flesh almost throughout the year, although the fruit harvested in the winter had a better visual appeal in terms of color. Both fruit cultivars harvested in the autumn had higher soluble solids and lower acidity. The highest concentrations of total phenolic content and L-ascorbic acid were observed in the spring and summer season harvested fruits although there was no significant difference between those (P > 0.05). It was concluded that the growth in the greenhouse minimizes the harvest season effects on papaya fruit quality. Thus, greenhouse cultivation is recommended for a higher quality product, especially in a subtropical climate.

Optimisation of food grade mixed surfactant-based l-ascorbic acid nanoemulsions using response surface methodology.

Co‐surfactant free l‐ascorbic acid (LAA) nanoemulsions were prepared using mixed surfactants (Soya lecithin and Tween 80). Response surface methodology (RSM) was used to optimise the emulsifying conditions for LAA nanoemulsions. The effects of water proportion (6%–14% w/w), homogenisation pressure (80–160 MPa), surfactant concentrations (4%–12% w/w) and laa concentration (0.5–1.3 w/w) on responses (size of droplets and nanoemulsion stability) were investigated. RSM results showed that the values of responses can be successfully predicted through second‐order polynomial model. The coefficients of determinations for droplet size and nanoemulsion stability were 0.9375 and 0.9027, respectively. The optimum preparation conditions for l‐LAA nanoemulsion were 9.04% water proportion, 114.48 MPa homogenisation pressure, 7.36% surfactant concentration and 1.09% LAA concentration. At the end of one month storage study, the retention of LAA in optimised nanoemulsions stored at 4°C and 25°C were 74.4% and 66.7%, respectively. These results may provide valuable contributions for food and pharmaceutical industry to develop delivery system for food additives and nutraceutical components.

Persistent free radicals in humin under redox conditions and their impact in transforming polycyclic aromatic hydrocarbons

The role of humic substance-associated persistent free radicals (PFRs) in the fate of organic contaminants under various redox conditions remains unknown. This study examined the characterization of original metal-free peat humin (HM), and HM treated with varying concentrations of H2O2 and L-ascorbic acid (VC) (assigned as H2O2-HM and VC-HM). The concentration of PFRs in HM increased with the addition of VC/H2O2 at concentrations less than 0.08 mol/L. The evolution of PFRs in HM under different environmental conditions (e.g., oxic/anoxic and humidity) was investigated. Two types of PFRs were detected in HM: a relatively stable radical existed in the original sample, and the other type, which was generated by redox treatments, was relatively unstable. The spin densities of VC/H2O2-HM readily returned to the original value under relatively high humidity and oxic conditions. During this process, the HM-associated “unstable” free radicals released an electron to O2, inducing the formation of reactive oxygen species (ROS, i.e., ⦁OH and ⦁O2−). The generated ROS promoted the degradation of polycyclic aromatic hydrocarbons based on the radical quenching measurements. The transformation rates followed the order naphthalene>phenanthrene>anthracene>benzo[a]pyrene. Our results provide valuable insight into the HM-induced transformation of organic contaminants under natural conditions.

Bio-Electrochemical Analysis of L-Ascorbic Acid Concentration in between Glaucoma/Cataract Patients Aqueous Humor

Glaucoma is the second leading causes of vision loss in the world after cataract and irreversible, particularly among the elderly, several years past, most of the molecular mechanisms leading to primary open angle glaucoma (POAG) are still unknown, however scientists discovered ascorbic acid (AA) concentration is reduced in cataract and glaucomatous patients aqueous humor compared with healthy eyes.For understand relationship between AA concentration and glaucoma, we try to develop a simple, sensitive and accurate sensor device for detection in AA . Electrochemical sensor featured with short analytical time, low cost, high sensitivity compared with other methods, in this work, a new electrochemical aptamer sensor for detecting AA was fabricated based on AA specific aptamer linked with polydopmine (PD) layer and immobilized on screen printed carbon electrode (SPCE). Cyclic voltammetry (CV) was used to investigate AA concentration dropped on modified electrode .Both analyze real human aqueous humor sample or commercial AA solution , aptamer electrode performed a good accuracy compared with high performance liquid chromatography (HPLC).

Influence of Harvest Stage and Rootstock Genotype on Compositional and Sensory Profile of the Elongated Tomato cv. “Sir Elyan”

The present experiment addressed the effects of two harvest stages, namely breaker (S1) and turning (S2), on compositional and sensory profile of grafted, greenhouse elongated tomatoes cv. “Sir Elyan”. The rootstocks “He-Man”, “Interpro”, and “Armstrong” were used. The S1 fruits showed a higher dry matter content, firmness and titratable acidity when compared to the S2 ones (by 6%, 3%, and 15%, respectively). They showed, also, the highest L-ascorbic acid concentration and antioxidant activity. Differently, soluble solid content, lycopene and β-carotene increased in the S2 fruits (by 4%, 92%, and 26%, respectively). Excepting methyl salicylate, all the volatiles detected peaked in the S2 fruits, which were scored by panelists as sweeter and more flavorful than the S1 ones. Among the rootstock genotypes, “He-Man” promoted fruits firmness, carotenoids concentration and antioxidant activity, irrespective of the harvest stage. “Interpro” enhanced the sensory attributes of the S1 fruits in terms of bitterness, sourness, sweetness and flavor. Differently, sweetness, sourness, and tomato flavor of the S2 fruits were promoted by “Armstrong”. The results highlight the influence of rootstock genotype on the nutraceutical and sensorial profile of “Sir Elyan” fruits harvested at early ripening stages.

Synergistic leaching of valuable metals from spent Li-ion batteries using sulfuric acid- l-ascorbic acid system

With increase in the number of scrapped portable electronics and new energy powered vehicles, the production of spent Li-ion batteries (LIBs) has increased progressively each year. Harmful substances in spent LIBs can pollute the environment and threaten human health. A sustainable technology should be developed to recycle the spent LIBs. Accordingly, a new environmentally friendly hydro-metallurgical process was proposed for leaching Li, Co, Ni, and Mn from spent LIBs using sulfuric acid with l-ascorbic acid as a reductant. Over the leaching process, several parameters, including sulfuric acid and l-ascorbic acid concentrations, solid to liquid ratio, temperature and time were systematically investigated. The maximum recovery efficiencies of Li, Co, Ni, and Mn were as high as 99.69%, 99.56%, 99.60%, and 99.87% under the optimized conditions (C(H2SO4 concentration) = 1.5 mol/L, C(C6H8O6 concentration) = 0.25 mol/L, the agitation speed was 300 r/min, the liquid–solid ratio was 15 mL/g, and the temperature was 333 K for 60 min), respectively. The synergistic mechanism was analyzed by X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared spectroscopy of the structure of cathode materials, residues, and leachate. The analysis results indicate that the dissolution rate of Ni, Mn, and Co was significantly improved under the condition of adding l-ascorbic acid as a reducing agent. Finally, 98.96 of Ni, 99.57% of Mn, 99.76% of Co, and 89.81% of Li were recovered in the form of C8H14N4NiO4, MnCO3, CoC2O4, and Li2CO3 through precipitation-solvent extraction methods.

A novel mıcrobıal bıosensor system based on C. tropicalis yeast cells for selectıve determınatıon of L-Ascorbıc acid

In this study, a novel microbial biosensor was developed for the selective determination of L-Ascorbic acid. In the construction of the microbial biosensor, lyophilized Candida tropicalis yeast cells were immobilized with o-aminophenol by forming a film layer on a platinum electrode surface using electropolymerization. L-Ascorbic acid was quantified on the basis of both amperometric and differential pulse voltammetry (DPV) methods using the biosensor. The measurements were made at +0.24 V (vs Ag/AgCl) for amperometric studies and between 0.0 V and +0.7 V for DPV studies based on the oxidation of L-Ascorbic acid to dehydro-L-Ascorbic acid by ascorbate oxidase which takes place within the catabolic metabolic pathway of C. tropicalis yeast cells. According to the results obtained from the two methods, the response of the biosensor depends linearly on L-Ascorbic acid concentration between 100 and 1500 μM. The detection limit was 62 μM and 59 μM for amperometric and DPV measurements, respectively. The response time of the microbial biosensor was 14 s and 5 s for DPV and amperometric measurements, respectively. In the optimization studies of the biosensor, some parameters such as the optimum amount of the microorganism, o-aminophenol concentration, pH and temperature were determined. For the characterization of the biosensor, reproducibility, storage stability and the effect of interferences were determined.

The compartmentalised nature of the mechanisms governing superoxide formation and scavenging in cells exposed to arsenite

In this study, respiration-proficient (RP) and -deficient (RD) cells were exposed to 2.5 or 10 μM arsenite to generate superoxide (O2-.) respectively in the mitochondrial respiratory chain or via NADPH oxidase activation. These treatments, while causing similar, although mitochondrial permeability transition-dependent (RP-cells) or independent (RD-cells), delayed apoptosis, surprisingly generated identical kinetics and levels of dihydrorhodamine oxidation, indicative of O2-. formation. These similarities were attributable to the involvement of a common upstream event resulting in activation of the two O2-.-generating systems, and to intrinsic features of the cells. Both mechanisms required an initial and sequential mobilization of Ca2+ from the inositol-1,4,5-trisphosphate receptor and the ryanodine receptor (RyR), with however different implications. The close contacts existing between the RyR and the mitochondria created optimal conditions for the Ca2+ clearance, and the ensuing formation of O2-. in RP-cell mitochondria. Exposure to low concentrations of l-ascorbic acid (AA) transported by high affinity mechanisms in cells and mitochondria, suppressed O2-. formation. Much more Ca2+, and hence more arsenite, was necessary to promote NADPH oxidase activation in RD-cells, as a consequence of the cytosolic dilution and mitochondrial clearance of Ca2+. For the same reasons, an exposure to high concentrations of AA was required to suppress O2-. formation under these conditions.

Surfactant-dependant thermally induced nonlinear optical properties of l-ascorbic acid-stabilized colloidal GNPs and GNP-PVP thin films.

Gold nanoparticle (GNP) colloids stabilized with various concentrations of l-ascorbic acid were synthesized by the chemical reduction method and characterized by UV-Vis spectroscopy, XRD, FT-IR spectroscopy and TEM. XRD and TEM studies confirmed the reduction in particle size with the stabilizer concentration. UV-Vis spectra showed a blue shift in the LSPR peak. FT-IR peaks ascertained the strong encapsulation of GNPs with l-ascorbic acid functional groups. The nonlinear optical (NLO) properties of colloidal GNPs and GNP–PVP composite thin film were investigated using the Z-scan technique with CW laser excitation at 632.8 nm. The effects of stabilizer concentrations on nonlinear refractive index (n2), nonlinear absorption coefficient (β) and third-order susceptibility (χ(3)) of colloidal GNPs and GNP–PVP composite thin films were investigated. The values of the NLO parameters for the thin films were as large as n2 = 10−5 cm2 W−1, β = 10−5 cm W−1 and χ(3)eff = 10−5 esu. For colloidal GNPs, these parameters were n2 = 10−6 cm2 W−1, β = 10−6 cm W−1 and χ(3)eff = 10−7 esu. In both these cases, the NLO parameter values were found to decrease as the stabilizer concentration increased from 1 to 5 mM. The considerable enhancement in the NLO parameters may be attributed to the thermal lensing effect originating from the thermo-optic phenomenon. From the results, the influence of the concentration of the stabilizer on the NLO properties is obvious.