Compared with natural enzymes, nanozymes have the advantages of high stability and low cost;however,selectivity and sensitivity are key issues that prevent their further development. In this study, we report a cascade...Compared with natural enzymes, nanozymes have the advantages of high stability and low cost;however,selectivity and sensitivity are key issues that prevent their further development. In this study, we report a cascade nanozymatic system with significantly improved selectivity and sensitivity that combines more substrate-specific reactions and sensitive fiuorescence detection. Taking detection of ascorbic acid(AA)as an example, a cascade catalytic reaction system consisting of oxidase-like N-doped carbon nanocages(NC) and peroxidase-like copper oxide(Cu O) improved the reaction selectivity in transforming the substrate into the target product by more than 1200 times against the interference of uric acid. The cascade catalytic reaction system was also applicable for transfer from open reactors into a spatially confined microfiuidic device, increasing the slope of the calibration curves by approximately 1000-fold with a linear detection range of 2.5 nmol/L to 100 nmol/L and a low limit of detection of 0.77 nmol/L. This work offers a new strategy that achieves significant improvements in selectivity and sensitivity.展开更多
Fresh-cut lettuce is widely used in ready-to-eat salads sold in modified atmosphere packages (MAP).Even in MAP,fresh-cut lettuce has short shelf life that results in loss of nutrients.Lettuce cultivars exhibit genetic...Fresh-cut lettuce is widely used in ready-to-eat salads sold in modified atmosphere packages (MAP).Even in MAP,fresh-cut lettuce has short shelf life that results in loss of nutrients.Lettuce cultivars exhibit genetic variation for shelf life in MAP,but their variation for nutrient retention is not known.Fifty accessions were evaluated for initial content of ascorbic acid (AsA),carotenoids,and sugars and their retention in storage.Accessions with high content and/or good retention of one or more nutrients were identified.The romaine accession ‘Floricos’ had high levels of all the three nutrients.Accessions with relatively high retention of all the three nutrients were ‘Salinas 88’,‘Siskiyou’,‘Solar’,SM09A,‘Romance’,and ‘Green Towers’.Romaine cultivars,‘Balady Barrage’,‘Green Towers’,and ‘Darkland’ had relatively high initial levels of all tested nutrients and good rate of their retention.There was no clear correlation between initial AsA/carotene concentrations and their retention rates,suggesting that besides content,retention of nutrients should also be a breeding target in a lettuce nutritional improvement program.Statistical analyses with the Pearson's correlation coefficient determined a negative relationship between tissue deterioration(AUDePS) and retention of all tested nutrients[r of-0.52 (P<0.0001) for AsA,-0.27 (P<0.01) for total carotene,and-0.59 (P<0.0001) for total sugars],suggesting that an increase in tissue deterioration intensifies nutrient decay.Broad-sense heritability (H^(2)) across the experiments was0.15 for AsA,0.23 for total carotene,and 0.50 for total sugars.Identification of germplasm with high nutrient content,extended shelf life and good nutrient retention provides valuable information for the lettuce industry and associated breeding programs.展开更多
Objective:To investigate the potential of ascorbic acid in mitigating reproductive toxicity induced by di-(2-ethyl hexyl)phthalate(DEHP)in female Wistar rats,focusing on oxidative stress,hormone levels,and gonadotropi...Objective:To investigate the potential of ascorbic acid in mitigating reproductive toxicity induced by di-(2-ethyl hexyl)phthalate(DEHP)in female Wistar rats,focusing on oxidative stress,hormone levels,and gonadotropin receptors expression.Methods:Forty female Wistar rats[30 days old,weighing(60±10)g]were randomly divided into five groups(n=8 per group).Group 1 received corn oil(control).Groups 2 and 3 were administered DEHP at 10 and 100 mg/kg body weight(b.wt.),respectively.Groups 4 and 5 received DEHP at 10 and 100 mg/kg b.wt.,respectively,plus ascorbic acid 100 mg/kg b.wt..All treatments were given orally for 30 days.Blood and ovarian tissues were collected to assess serum reproductive hormones,gonadotropin receptor gene expression,oxidative stress markers,and apoptosis.Results:DEHP,particularly at the higher dose,significantly decreased hormone levels(follicle-stimulating hormone,luteinizing hormone,estradiol)and gonadotropin receptor gene expression(FSHR,LHR),while increasing oxidative stress and apoptosis.Co-treatment with ascorbic acid significantly improved these parameters,reducing oxidative stress and apoptosis,and restoring hormone levels and gonadotropin receptor expression.Histopathology revealed fewer atretic follicles and less disruption in ovarian structure in DEHP and ascorbic acid-treated groups compared to those treated with DEHP alone.Conclusions:Ascorbic acid demonstrates protective effects against DEHP-induced reproductive toxicity in female rats,likely through mitigating oxidative stress and normalizing hormone levels and ovarian function.展开更多
Cu nanoparticles were prepared by reducing Cu2＋ ions with ascorbic acid through aqueous solution reduction method. The effects of solution pH and average size of Cu2O particles on the preparation of Cu nanoparticles ...Cu nanoparticles were prepared by reducing Cu2＋ ions with ascorbic acid through aqueous solution reduction method. The effects of solution pH and average size of Cu2O particles on the preparation of Cu nanoparticles were investigated. Cu particles were prepared at pH 3, 5 or 7, with the smallest Cu particles obtained at pH 7. However, Cu particles could not be prepared at pH 9 or 11. The average size of Cu2O particles can affect that of Cu particles. Larger Cu2O particles result in larger Cu particles. In addition, experiments were conducted to explore the reaction process by measuring the X-ray diffraction （XRD） patterns of specimens collected at different time points during the reaction. It was found that Cu（OH）2 was initially formed as a precursor, followed by the formation of Cu2O, which was finally reduced to Cu particles.展开更多
Objective: To study synergistic effect with Ascorbic acid(AA) on arsenic trioxide inducing human Hepatocarcinoma cell apoptosis, and provide theoretical basis for promoting human Hepatocarcinoma cell apoptosis induced...Objective: To study synergistic effect with Ascorbic acid(AA) on arsenic trioxide inducing human Hepatocarcinoma cell apoptosis, and provide theoretical basis for promoting human Hepatocarcinoma cell apoptosis induced by arsenic trioxide(AT). Methods: Human Hepatocarcinoma cell line BEL-7402 being cultured in vitro, the effect of AT and (or) AA on its growth inhibition and its two intracellular signal molecules was evaluated separately using MTT and Western blot. Results: AT at a few μmol/L concentration could suppress abnormal proliferation of human hepatocarcinoma cells, and initiate their apoptosis by activation of caspase-3, and activate extracellular-signal regulated kinases (ERKs), which were dependent on the dosage of AT conspicuously. The effect of AA on BEL-7402 was not significant; However, AA could effectively enhance AT-induced hepatocarcinoma cell apoptosis and lesion severity through activation of caspase-3 but not ERKs. Conclusion: Caspase-3 and ERKs proteins could involve in arsenic-induced hepatocarcinoma cell apoptosis and differentiation respectively as intracellular signaling molecules; The effect between AT and AA on hepatocarcinoma is synergistic, which further inhibits cell growth and induces apoptosis in human hepatocarcinoma cells through activation of caspase-3 but not ERKs.展开更多
Aim:To study the detrimental effects of cyclophosphamide on the testicular androgenic and gametogenic activities through endocrine inhibition and/or induction of oxidative stress in male albino rats and to evaluate th...Aim:To study the detrimental effects of cyclophosphamide on the testicular androgenic and gametogenic activities through endocrine inhibition and/or induction of oxidative stress in male albino rats and to evaluate the protective effect of ascorbic acid.Methods:The testicular△^(5),3β-hydroxysteroid dehydrogenase(HSD),17β-HSD,peroxidase and catalase activities along with the levels of malondialdehyde(MDA)and conjugated dienes in testicular tissue were measured for the evaluation of testicular oxidative stress.The plasma testosterone(T)level was measured by immunoassay.Various germ cells at stageⅦof spermatogenic cycle were quantified from testicular stained sections.Results:Cyclophosphamide treatment results in a significant inhibition in the testicular△^(5),3β-HSD and 17β-HSD activities,a decrease in plasma T level and a diminution in the counts of various germ cells.Moreover,this treatment was also associated with a significant inhibition of the peroxidase and catalase activities along with high levels of MDA and conjugated dienes in the testis.All these changes were reversed by ascorbic acid co-administration.Conclusion:Cyclophosphamide treatment at the dosage used caused testicular gametogenic and androgenic disorders as well as induced testicular oxidative stress that can be reversed by ascorbic acid co-administration.展开更多
AIM： To investigate the effectiveness of low-volume plus ascorbic acid [polyethylene glycol plus ascorbic acid （PEG ＋ Asc）] and high-volume plus simethicone [polyethylene glycol plus simethicone （PEG ＋ Sim）] bo...AIM： To investigate the effectiveness of low-volume plus ascorbic acid [polyethylene glycol plus ascorbic acid （PEG ＋ Asc）] and high-volume plus simethicone [polyethylene glycol plus simethicone （PEG ＋ Sim）] bowel preparations. METHODS： A total of one hundred and forty-four outpatients （76 males）, aged from 20 to 84 years （median age 59.5 years）, who attended our Department, were divided into two groups, age and sex matched, and underwent colonoscopy. Two questionnaires, one for patients reporting acceptability and the other for endoscopists evaluating bowel cleansing effectiveness according to validated scales, were completed. Indications, timing of examination and endoscopical findings were recorded. Biopsy forceps were used as a measuring tool in order to determine polyp endoscopic sizeestimation. Difficulty in completing the preparation was rated in a 5-point Likert scale （1 = easy to 5 = unable）. Adverse experiences （fullness, cramps, nausea, vomiting, abdominal pain, headache and insomnia）, number of evacuations and types of activities performed during preparation （walking or resting in bed） were also investigated. RESULTS： Seventy-two patients were selected for each group. The two groups were age and sex matched as well as being comparable in terms of medical history and drug therapies taken. Fourteen patients dropped out from the trial because they did not complete the preparation procedure. Ratings of global bowel cleansing examinations were considered to be adequate in 91% of PEG ＋ Asc and 88% of PEG ＋ Sim patients. Residual Stool Score indicated similar levels of amount and consistency of residual stool; there was a significant difference in the percentage of bowel wall visualization in favour of PEG ＋ Sim patients. In the PEG ＋ Sire group, 12 adenomas≤ 10 mm diameter （5/left colon ＋ 7/right colon） vs 9 （8/left colon ＋ 1/right colon） in the PEG ＋ Asc group were diagnosed. Visualization of small lesions seems to be one of the primary advantages of the PEG ＋ Sim preparation. CONCLUSION： PEG ＋ Asc is a good alternative solution as a bowel preparation but more improvements are necessary in order to achieve the target of a perfect preparation.展开更多
Wallerian degeneration occurs after peripheral nerve injury and provides a beneficial microenvironment for nerve regeneration.Our previous study demonstrated that ascorbic acid promotes peripheral nerve regeneration,p...Wallerian degeneration occurs after peripheral nerve injury and provides a beneficial microenvironment for nerve regeneration.Our previous study demonstrated that ascorbic acid promotes peripheral nerve regeneration,possibly through promoting Schwann cell proliferation and phagocytosis and enhancing macrophage proliferation,migration,and phagocytosis.Because Schwann cells and macrophages are the main cells involved in Wallerian degeneration,we speculated that ascorbic acid may accelerate this degenerative process.To test this hypothesis,400 mg/kg ascorbic acid was administered intragastrically immediately after sciatic nerve transection,and 200 mg/kg ascorbic acid was then administered intragastrically every day.In addition,rat sciatic nerve explants were treated with 200μM ascorbic acid.Ascorbic acid significantly accelerated the degradation of myelin basic protein-positive myelin and neurofilament 200-positive axons in both the transected nerves and nerve explants.Furthermore,ascorbic acid inhibited myelin-associated glycoprotein expression,increased c-Jun expression in Schwann cells,and increased both the number of macrophages and the amount of myelin fragments in the macrophages.These findings suggest that ascorbic acid accelerates Wallerian degeneration by accelerating the degeneration of axons and myelin in the injured nerve,promoting the dedifferentiation of Schwann cells,and enhancing macrophage recruitment and phagocytosis.The study was approved by the Southern Medical University Animal Care and Use Committee(approval No.SMU-L2015081)on October 15,2015.展开更多
The magnesium sulfate leaching technology for the ion-absorbed rare earths ore can solve the ammonia pollution problem existing in ammonium sulfate leaching process. However, the leaching capacity of magnesium sulfate...The magnesium sulfate leaching technology for the ion-absorbed rare earths ore can solve the ammonia pollution problem existing in ammonium sulfate leaching process. However, the leaching capacity of magnesium sulfate is slightly weaker than that of ammonium sulfate, resulting in a bigger consumption of magnesium sulfate. In this paper, the MgSO4-ascorbic acid compound leaching agent had been demonstrated to deal with the ion-absorbed rare earths ore. The ascorbic acid could form a stable coordination with rare earth ions, so that it can strengthen the leaching of ion-exchangeable phase.Moreover, ascorbic acid has a strong reductive property, it can leach the colloidal sediment phase rare earth as well. The present study investigates the effect of the initial pH and the composition of leaching agent on the rare earth leaching. It is determined that the rare earth leaching efficiency is 107.5% under the condition of pH 2.00,0.15 mol/L magnesium sulfate and 1.0 g/L ascorbic acid in leaching agent. In this case, the content of the ion-exchangeable phase and colloidal sediment phase rare earth in the leaching residues are both only 0.02‰. The leaching efficiency of colloid sediment phase rare earth can be 85.7%,so that the Ce partition in the leaching liquor increases to be 5.77%. The magnesium-ascorbic acid compound leaching agent is proposed to be a promising choice to deal with the ion-absorbed rare earths ore, which can realize the efficient leaching, low consumption of MgSO4 and environmentally friendly leaching.展开更多
The effects of exogenous ascorbic acid and silicium on leaf fresh weigh, seed yield, photosynthesis, changes of the activities of major antioxidant enzymes, nitrate reductase activity, proline accumulation, chlorophyl...The effects of exogenous ascorbic acid and silicium on leaf fresh weigh, seed yield, photosynthesis, changes of the activities of major antioxidant enzymes, nitrate reductase activity, proline accumulation, chlorophyll content, and fatty acid composition were investigated in salt-stressed canola. A hydroponic pot experiment was conducted based on randomized complete block design, factorial arrangement was used with 16 combinations of salinity stress （0, 100, 200, and 300 mmol L-1 NaC1）, ascorbic acid （0 and 30 mmol L-1）, and silicium （2 and 4 mmol L-1 from potassium silicate） with three replicates. The results showed that salinity significantly decreased leaf area and leaf fresh weight, seed yield, photosynthesis, nitrate reductase activity, chlorophyll content, and seed protein percentage. Conversely, respiration, antioxidant enzymes activity, proline accumulation, and linolenic acid percentage increased due to salt stress. Ascorbic acid application improved photosynthesis and seed yield and mitigated antioxidant enzyme activity. In addition, nitrate reductase activity and chlorophyll a and b were positively affected by ascorbic acid. Regarding silicium application, that was found that leaf area, leaf fresh weight, seed yield and photosynthesis, ascorbate peroxidase activity, nitrate reductase activity, and chlorophyll content increased, while respiration decreased. Furthermore, silicium had not significant effect on antioxidant enzyme activity. In general, ascorbic acid and silicium were involved in the defensive mechanisms against salinity stress and it can be suggested that, ascorbic acid and silicium application had positive effect on canola growth under conditions of salt stress.展开更多
The magnesium sulfate(MgSO_(4))-ascorbic acid(Vc)compound leaching technique can extract rare earth elements(REEs)existing in ion-exchangeable phase and colloidal phase from ion-adso rption type rare earth ore through...The magnesium sulfate(MgSO_(4))-ascorbic acid(Vc)compound leaching technique can extract rare earth elements(REEs)existing in ion-exchangeable phase and colloidal phase from ion-adso rption type rare earth ore through the synergy effect of coordination and reduction,but its reaction process and mechanism remain unclear.In this paper,the coordination-reduction leaching mechanism was analyzed from the perspectives of leaching thermodynamics and kinetics,which provide theoretical guidance for the compound leaching process.In the case of neodymium,about 45%of dissolved neodymium will exist as the complex species of NdVc_(()3(aq))in Nd-Vc-sulfate system.Based on this,it is deduced that the Gibbs free energy of the leaching reaction of ion-exchangeable phase REEs will change to a more negative value through the coordination of REEs cations and Vc anions in the MgSO_(4)leaching process.In addition,the E_(h)-pH diagrams of Ce-SO_(4)^(2-)-H_(2)O and Fe-SO_(4)^(2-)-H_(2)O together with the dissolution experiments confirm that the added Vc initiates the leaching process of colloidal phase REEs through reduction-dissolution reaction.Through the study of leaching kinetics,the leaching of REEs is controlled by diffusion and chemical reaction in the co mpound leaching system since colloidal phase REEs are leached.Therefore,the addition of Vc can shift the leaching equilibrium to a more favorable state and accelerate leaching process.The rare earth leaching efficiency of ion-exchangeable phase and colloidal phase can be effectively improved by increasing the reaction temperature,the conce ntrations of leaching agent and Vc,and the leaching agent acidity.展开更多
Tea polyphenols have been shown to have anticancer activity in many studies.In the present study,we investigated effects of theaflavin-3-3'-digallate(TF3),one of the major theaflavin monomers in black tea,in combi...Tea polyphenols have been shown to have anticancer activity in many studies.In the present study,we investigated effects of theaflavin-3-3'-digallate(TF3),one of the major theaflavin monomers in black tea,in combination with ascorbic acid(AA),a reducing agent,and(-)-epigallocatechin-3-gallate(EGCG),the main polyphenol presented in green tea,in combination with AA on cellular viability and cell cycles of the human lung adenocarcinoma SPC-A-1 cells.The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT) assay showed that the 50% inhibition concentrations(IC50) of TF3,EGCG,and AA on SPC-A-1 cells were 4.78,4.90,and 30.62 μmol/L,respectively.The inhibitory rates of TF3 combined with AA(TF3+AA) and EGCG combined with AA(EGCG+AA) at a molar ratio of 1:6 on SPC-A-1 cells were 54.4% and 45.5%,respectively.Flow cytometry analysis showed that TF3+AA and EGCG+AA obviously increased the cell population in the G0/G1 phase of the SPC-A-1 cell cycle from 53.9% to 62.8% and 60.0%,respectively.TF3-treated cells exhibited 65.3% of the G0/G1 phase at the concentration of its IC50.Therefore,TF3+AA and EGCG+AA had synergistic inhibition effects on the proliferation of SPC-A-1 cells,and significantly held SPC-A-1 cells in G0/G1 phase.The results suggest that the combination of TF3 with AA or EGCG with AA enhances their anticancer activity.展开更多
Cerium-based conversion coatings were formed on AZ91D magnesium alloy by immersion of the substrate in solutions containing Ce(NO_(3))_(3),H_(2)O_(2) and ascorbic acid(HAsc).The characterisation of the films was perfo...Cerium-based conversion coatings were formed on AZ91D magnesium alloy by immersion of the substrate in solutions containing Ce(NO_(3))_(3),H_(2)O_(2) and ascorbic acid(HAsc).The characterisation of the films was performed by electrochemical and surface analysis techniques such as SEM,EDS,X-ray diffraction and X-ray photoelectron spectroscopy(XPS).The degree of corrosion protection achieved was evaluated in simulated physiological solution by the open circuit potential monitoring,polarisation techniques and electrochemical impedance spectroscopy(EIS).The presence of HAsc in the conversion solution causes changes in the morphology,adherence and anticorrosive performance of the films.The improvement in the corrosion resistance is closely associated with the corrosion inhibition properties of HAsc.展开更多
Background: Laying hens over 75 weeks of age commonly show great declines in immunity and production performance.It is unclear whether these declines can be relieved by supplementing with ascorbic acid(AA) in feed.Two...Background: Laying hens over 75 weeks of age commonly show great declines in immunity and production performance.It is unclear whether these declines can be relieved by supplementing with ascorbic acid(AA) in feed.Two trials were conducted to investigate the synthesis and metabolism of AA in layers of different ages and the effects of dietary supplemental AA on the performance and the immune and antioxidant statuses of 78 weeks old hens.Methods: In Exp.1,equal numbers(24 hens) of 35 weeks old(Young) and 75 weeks old(Old) layers were fed the same diet without AA supplementation for 4 weeks.In Exp.2,360 healthy 78 weeks old laying hens were randomly assigned to 4 treatments(basal diet supplemented with 0,0.25,0.5,or 1 g AA/kg diet) in an 8-week feeding trial.Results: The old hens tended to have decreased L-gulonolactone oxidase(GLO) synthase activity in the kidney and liver than that of the young hens(P = 0.07 and P = 0.05,respectively).Compared with the young hens,the old hens had lower hepatic antioxidant capacity allowing for the lower thioredoxin(TXN),thioredoxin reductase(TXNR) and cytochrome b5 reductase(CYB5 R) gene expression(P < 0.05),whereas increased sodium-dependent vitamin C transporter(SVCT) 1 expression levels in the ileum and kidney and enhanced splenic and hepatic AA concentrations(P < 0.05).Dietary supplementation with AA significantly decreased GLO enzyme activity but increased splenic AA concentration and anti-bovine serum albumin IgG levels(P < 0.05) and tended to increase CD4+T lymphocyte numbers(P = 0.06) in serum.Supplementation of 0.25 g AA/kg diet significantly increased hepatic total antioxidant capacity(T-AOC,P < 0.05) relative to the control group.Conclusions: Laying hens could synthesize AA in both the kidney and the liver,though the GLO enzyme activities were 100 times greater in kidneys than in livers.The old laying hens had greater absorption and reabsorption capacity and higher AA retention in some tissues that did the young hens.Dietary supplementation of AA can improve the health of old layers by enhancing immunity and antioxidant capacity.展开更多
Objective To find out the mechanisms of redifferentiation and reversion of malignant human gastric cancer cells induced by ascorbic acid. Methods Human gastric cancer cells grown in the laboratory were used. The Trypa...Objective To find out the mechanisms of redifferentiation and reversion of malignant human gastric cancer cells induced by ascorbic acid. Methods Human gastric cancer cells grown in the laboratory were used. The Trypan blue dye exclusion method was used to determine the cell doubling time. The electrophoresis rate and colonogenic potential were the indices used to measure the rate of redifferentiation. The content of malondialdehyde （MDA） was measured using the thiobarbituric acid （TBA） method. The activities of superoxide dismutase （SOD）, catalase （CAT） and the content of H2O2 were evaluated by spectrophotography. Results Six mmol/L ascorbic acid was used as a positive control. Human gastric cancer cells were treated with 75 μm hydrogen peroxide, which alleviated many of the malignant characteristics. For example, the cell surface charge obviously decreased and the electrophoresis rate dropped from 2.21 to 1.10 pm·s^-1·cm^-1 The colonogenic potential, a measure of cell differentiation, decreased 90.2%. After treatment with ascorbic acid, there was a concentration- and time-dependent increase in hydrogen peroxide （H2O2） and the activity of superoxide dismutase （SOD）. However, the activity of catalase （CAT） resulted in a concentration- and time-dependent decrease. SOD and 3-amino- 1,2,4-triazole （AT） exhibited some effects, but there were statistically significant differences between the SOD and AT group and the H2O2 group, Conclusions Ascurbic acid induces growth inhibition and redifferentiation of human gastric cancer cells through the production of hydrogen peroxide.展开更多
Lead is a ubiquitous environmental and industrial pollutant that may have toxic effects on the male. Vitamins may protect against toxic effects of lead in the liver and reproductive system, which is confirmed by our i...Lead is a ubiquitous environmental and industrial pollutant that may have toxic effects on the male. Vitamins may protect against toxic effects of lead in the liver and reproductive system, which is confirmed by our initial research. The aim of this study was to further investigate the protective effects of vitamins （ascorbic acid combined with thiamine） on lead acetate （Pb）-induced reproductive toxicities in mice and study the possible mechanisms underlying these effects. Forty-five male mice were randomly divided into 3 groups, 15 mice in each and received daily intragastric administration with control, Pb （20 mg/kg）, and Pb＋vitamins （ascorbic acid of 420 mg/kg＋thiamine of 30 mg/kg） for 6 weeks, respectively. The Pb-treated animals showed significant decreases in the epididymal sperm count and motility compared to the control group, while the Pb＋vitamins group had significant increases for these variables. Moreover, an increasing apoptosis of germinal cells induced by Pb was reduced by vitamin treatment. Pb induced the activation of Caspase-3, Fas/Fas-L and Bcl-2 with elevated levels, and the adaptor protein primarily regulated signaling through Fas and required for Fas-induced apoptosis. In conclusion, ascorbic acid combined with thiamine exhibited protective effect on reproductive system by inhibiting Pb-induced excessive cell apoptosis.展开更多
The kinetics of dissolved O_2 reduction and hydrogen evolution reactions on copper surface was studied in naturally aerated and air and O_2-saturated 0.50 mol/L H_2SO_4 solutions using polarization measurements combin...The kinetics of dissolved O_2 reduction and hydrogen evolution reactions on copper surface was studied in naturally aerated and air and O_2-saturated 0.50 mol/L H_2SO_4 solutions using polarization measurements combined with the rotating disc electrode (RDE).The Koutecky-Levich plot indicated that the dissolved O_2 reduction at the copper electrode was an apparent four-electron process.A correlation between the presence of dissolved O_2 and the formation of Cu_2O,confirmed from XRD,was discussed. Ascorbic a...展开更多
BACKGROUND The current case report describes successful phacoemulsification with the aid of perioperative topical ascorbic acid(AA) in two patients with corneal endothelial disorders to prevent postoperative corneal e...BACKGROUND The current case report describes successful phacoemulsification with the aid of perioperative topical ascorbic acid(AA) in two patients with corneal endothelial disorders to prevent postoperative corneal endothelial decompensation.CASE SUMMARY Two eyes of two patients underwent phacoemulsification with pre-existing corneal endothelial disorders including Fuchs corneal endothelial dystrophy(Patient 1) and endotheliitis(Patient 2). Topical AA was applied to both patients at least one month before and after with a frequency of four times per day. After the surgery, both eyes improved best-corrected visual acuity(BCVA) and there was limited human corneal endothelial cell loss without signs of corneal endothelial decompensation, such as deteriorated BCVA or persistent corneal edema during the follow-up of at least two years.CONCLUSION Perioperative administration of topical AA may be an alternative therapy to the triple procedure in patients expecting to undergo cataract surgery.展开更多
Two-dimensional(2 D)titanium carbide(MXene)nanosheets exhibited excellent conductivity,flexibility,high volumetric capacity,hydrophilic surface,thermal stability,etc.So,it has been exploited in various applications.He...Two-dimensional(2 D)titanium carbide(MXene)nanosheets exhibited excellent conductivity,flexibility,high volumetric capacity,hydrophilic surface,thermal stability,etc.So,it has been exploited in various applications.Herein,we report synthesis of mixed phase 2 D MXene as a catalytic material for simultaneous detection of important biomolecules such as ascorbic acid(AA),dopamine(DA)and uric acid(UA).Crystalline structure,surface morphology and elemental composition of mixed phase titanium carbide(Ti-C-T_(x))MXene(T_(x)=-F,-OH,or-O)nanosheets were confirmed by X-ray diffraction(XRD),Raman spectroscopy,high-resolution transmission electron microscopy(HR-TEM),high-re solution scanning electron microscopy(HR-SEM)and Energy-dispersive X-ray spectroscopy(EDS)mapping analysis.Furthermore,Ti-C-T_(x) modified glassy carbon electrode(GCE)was prepared and its electrochemical properties are studied by cyclic voltammetry(CV)and diffe rential pulse voltammetry(DPV).It was found that Ti-C-T_(x) modified GCE(Ti-C-T_(x)/GCE)showed excellent electrocatalytic activity and separated oxidation peaks of important biomolecules such as AA(at 0.01 V),DA(at 0.21 V)and UA(at 0.33 V).Also,Ti-C-T_(x)/GCE sensor is enabled their simultaneous detection in physiological pH from 100 to 1000μM for AA,0.5-50μM for DA and 0.5-4μM&100-1500μM for UA.The limit of detection’s(LOD)was estimated as 4.6μM,0.06μM and 0.075μM for AA,DA and UA,respectively.Moreover,real sample analysis indicated that spiked AA,DA and UA can be determined accurately by Ti-C-T_(x)/GCE with the recovery ratio in the range between 100.5%-103%in human urine samples.The proposed Ti-C-T_(x) modified electrode exhibited good stability,selectivity and reproducibility as an electrochemical sensor for the detection of AA,DA and UA molecules.展开更多
A carbon paste electrode modified with electropolymerized fills of isonicotinic acid was developed. The modified electrode shows excellent electrocatalytic activity toward the oxidation of both dopamine （DA） and epi...A carbon paste electrode modified with electropolymerized fills of isonicotinic acid was developed. The modified electrode shows excellent electrocatalytic activity toward the oxidation of both dopamine （DA） and epinephrine （EP）. Separation of the reduction peak potentials for dopamine and epinephrine was about 357 mV in pH 5.3 phosphate buffer solution （PBS） and the character was used for the detection DA and EP simultaneously. The peak currents increase linearly with DA and EP concentration over the range of 8.0×10^-5 to 7.0×10^-4 mol/L and 5.0×10^-6 to 1.0×10^-4 mol/L with detection limits of 2×10^-5 and 1×10^-6 mol/L, respectively. The interference studies showed that the modified electrode exhibits excellent selectivity in the presence of large excess of ascorbic acid （AA）.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 22174014 and 22074015)。
文摘Compared with natural enzymes, nanozymes have the advantages of high stability and low cost;however,selectivity and sensitivity are key issues that prevent their further development. In this study, we report a cascade nanozymatic system with significantly improved selectivity and sensitivity that combines more substrate-specific reactions and sensitive fiuorescence detection. Taking detection of ascorbic acid(AA)as an example, a cascade catalytic reaction system consisting of oxidase-like N-doped carbon nanocages(NC) and peroxidase-like copper oxide(Cu O) improved the reaction selectivity in transforming the substrate into the target product by more than 1200 times against the interference of uric acid. The cascade catalytic reaction system was also applicable for transfer from open reactors into a spatially confined microfiuidic device, increasing the slope of the calibration curves by approximately 1000-fold with a linear detection range of 2.5 nmol/L to 100 nmol/L and a low limit of detection of 0.77 nmol/L. This work offers a new strategy that achieves significant improvements in selectivity and sensitivity.
基金supported by the Specialty Crop Block Grant Program of the U.S. Department of Agriculture's (USDA), Agricultural Marketing Service (AMS) through the California Department of Food and Agriculture (SCB15015)partly also by funding from the California Leafy Greens Research Board and by Oak Ridge Institute for Science and Education (ORISE) Research Participation Program。
文摘Fresh-cut lettuce is widely used in ready-to-eat salads sold in modified atmosphere packages (MAP).Even in MAP,fresh-cut lettuce has short shelf life that results in loss of nutrients.Lettuce cultivars exhibit genetic variation for shelf life in MAP,but their variation for nutrient retention is not known.Fifty accessions were evaluated for initial content of ascorbic acid (AsA),carotenoids,and sugars and their retention in storage.Accessions with high content and/or good retention of one or more nutrients were identified.The romaine accession ‘Floricos’ had high levels of all the three nutrients.Accessions with relatively high retention of all the three nutrients were ‘Salinas 88’,‘Siskiyou’,‘Solar’,SM09A,‘Romance’,and ‘Green Towers’.Romaine cultivars,‘Balady Barrage’,‘Green Towers’,and ‘Darkland’ had relatively high initial levels of all tested nutrients and good rate of their retention.There was no clear correlation between initial AsA/carotene concentrations and their retention rates,suggesting that besides content,retention of nutrients should also be a breeding target in a lettuce nutritional improvement program.Statistical analyses with the Pearson's correlation coefficient determined a negative relationship between tissue deterioration(AUDePS) and retention of all tested nutrients[r of-0.52 (P<0.0001) for AsA,-0.27 (P<0.01) for total carotene,and-0.59 (P<0.0001) for total sugars],suggesting that an increase in tissue deterioration intensifies nutrient decay.Broad-sense heritability (H^(2)) across the experiments was0.15 for AsA,0.23 for total carotene,and 0.50 for total sugars.Identification of germplasm with high nutrient content,extended shelf life and good nutrient retention provides valuable information for the lettuce industry and associated breeding programs.
文摘Objective:To investigate the potential of ascorbic acid in mitigating reproductive toxicity induced by di-(2-ethyl hexyl)phthalate(DEHP)in female Wistar rats,focusing on oxidative stress,hormone levels,and gonadotropin receptors expression.Methods:Forty female Wistar rats[30 days old,weighing(60±10)g]were randomly divided into five groups(n=8 per group).Group 1 received corn oil(control).Groups 2 and 3 were administered DEHP at 10 and 100 mg/kg body weight(b.wt.),respectively.Groups 4 and 5 received DEHP at 10 and 100 mg/kg b.wt.,respectively,plus ascorbic acid 100 mg/kg b.wt..All treatments were given orally for 30 days.Blood and ovarian tissues were collected to assess serum reproductive hormones,gonadotropin receptor gene expression,oxidative stress markers,and apoptosis.Results:DEHP,particularly at the higher dose,significantly decreased hormone levels(follicle-stimulating hormone,luteinizing hormone,estradiol)and gonadotropin receptor gene expression(FSHR,LHR),while increasing oxidative stress and apoptosis.Co-treatment with ascorbic acid significantly improved these parameters,reducing oxidative stress and apoptosis,and restoring hormone levels and gonadotropin receptor expression.Histopathology revealed fewer atretic follicles and less disruption in ovarian structure in DEHP and ascorbic acid-treated groups compared to those treated with DEHP alone.Conclusions:Ascorbic acid demonstrates protective effects against DEHP-induced reproductive toxicity in female rats,likely through mitigating oxidative stress and normalizing hormone levels and ovarian function.
文摘Cu nanoparticles were prepared by reducing Cu2＋ ions with ascorbic acid through aqueous solution reduction method. The effects of solution pH and average size of Cu2O particles on the preparation of Cu nanoparticles were investigated. Cu particles were prepared at pH 3, 5 or 7, with the smallest Cu particles obtained at pH 7. However, Cu particles could not be prepared at pH 9 or 11. The average size of Cu2O particles can affect that of Cu particles. Larger Cu2O particles result in larger Cu particles. In addition, experiments were conducted to explore the reaction process by measuring the X-ray diffraction （XRD） patterns of specimens collected at different time points during the reaction. It was found that Cu（OH）2 was initially formed as a precursor, followed by the formation of Cu2O, which was finally reduced to Cu particles.
文摘Objective: To study synergistic effect with Ascorbic acid(AA) on arsenic trioxide inducing human Hepatocarcinoma cell apoptosis, and provide theoretical basis for promoting human Hepatocarcinoma cell apoptosis induced by arsenic trioxide(AT). Methods: Human Hepatocarcinoma cell line BEL-7402 being cultured in vitro, the effect of AT and (or) AA on its growth inhibition and its two intracellular signal molecules was evaluated separately using MTT and Western blot. Results: AT at a few μmol/L concentration could suppress abnormal proliferation of human hepatocarcinoma cells, and initiate their apoptosis by activation of caspase-3, and activate extracellular-signal regulated kinases (ERKs), which were dependent on the dosage of AT conspicuously. The effect of AA on BEL-7402 was not significant; However, AA could effectively enhance AT-induced hepatocarcinoma cell apoptosis and lesion severity through activation of caspase-3 but not ERKs. Conclusion: Caspase-3 and ERKs proteins could involve in arsenic-induced hepatocarcinoma cell apoptosis and differentiation respectively as intracellular signaling molecules; The effect between AT and AA on hepatocarcinoma is synergistic, which further inhibits cell growth and induces apoptosis in human hepatocarcinoma cells through activation of caspase-3 but not ERKs.
基金The authors gratefully acknowledge the financial assistance from the Major Research Project(Project No.F-3/50/99 dated 3l-3-99)provided by the University Grants Commission(UGC),New Delhi,India
文摘Aim:To study the detrimental effects of cyclophosphamide on the testicular androgenic and gametogenic activities through endocrine inhibition and/or induction of oxidative stress in male albino rats and to evaluate the protective effect of ascorbic acid.Methods:The testicular△^(5),3β-hydroxysteroid dehydrogenase(HSD),17β-HSD,peroxidase and catalase activities along with the levels of malondialdehyde(MDA)and conjugated dienes in testicular tissue were measured for the evaluation of testicular oxidative stress.The plasma testosterone(T)level was measured by immunoassay.Various germ cells at stageⅦof spermatogenic cycle were quantified from testicular stained sections.Results:Cyclophosphamide treatment results in a significant inhibition in the testicular△^(5),3β-HSD and 17β-HSD activities,a decrease in plasma T level and a diminution in the counts of various germ cells.Moreover,this treatment was also associated with a significant inhibition of the peroxidase and catalase activities along with high levels of MDA and conjugated dienes in the testis.All these changes were reversed by ascorbic acid co-administration.Conclusion:Cyclophosphamide treatment at the dosage used caused testicular gametogenic and androgenic disorders as well as induced testicular oxidative stress that can be reversed by ascorbic acid co-administration.
文摘AIM： To investigate the effectiveness of low-volume plus ascorbic acid [polyethylene glycol plus ascorbic acid （PEG ＋ Asc）] and high-volume plus simethicone [polyethylene glycol plus simethicone （PEG ＋ Sim）] bowel preparations. METHODS： A total of one hundred and forty-four outpatients （76 males）, aged from 20 to 84 years （median age 59.5 years）, who attended our Department, were divided into two groups, age and sex matched, and underwent colonoscopy. Two questionnaires, one for patients reporting acceptability and the other for endoscopists evaluating bowel cleansing effectiveness according to validated scales, were completed. Indications, timing of examination and endoscopical findings were recorded. Biopsy forceps were used as a measuring tool in order to determine polyp endoscopic sizeestimation. Difficulty in completing the preparation was rated in a 5-point Likert scale （1 = easy to 5 = unable）. Adverse experiences （fullness, cramps, nausea, vomiting, abdominal pain, headache and insomnia）, number of evacuations and types of activities performed during preparation （walking or resting in bed） were also investigated. RESULTS： Seventy-two patients were selected for each group. The two groups were age and sex matched as well as being comparable in terms of medical history and drug therapies taken. Fourteen patients dropped out from the trial because they did not complete the preparation procedure. Ratings of global bowel cleansing examinations were considered to be adequate in 91% of PEG ＋ Asc and 88% of PEG ＋ Sim patients. Residual Stool Score indicated similar levels of amount and consistency of residual stool; there was a significant difference in the percentage of bowel wall visualization in favour of PEG ＋ Sim patients. In the PEG ＋ Sire group, 12 adenomas≤ 10 mm diameter （5/left colon ＋ 7/right colon） vs 9 （8/left colon ＋ 1/right colon） in the PEG ＋ Asc group were diagnosed. Visualization of small lesions seems to be one of the primary advantages of the PEG ＋ Sim preparation. CONCLUSION： PEG ＋ Asc is a good alternative solution as a bowel preparation but more improvements are necessary in order to achieve the target of a perfect preparation.
基金supported by the National Natural Science Foundation of China,Nos.81870982&81571182the Program for Changjiang Scholars and Innovative Research Team in Universities of China,No.IRT-16R37+4 种基金the National Key Basic Research Program of China,No.2014CB542202the Science and Technology Project of Guangdong Province of China,No.2015A020212024Key Research&Development Program of Guangzhou Regenerative Medicine and Health Guangdong Laboratory of China,No.2018GZR110104008the Natural Science Foundation of Guangdong Province of China,No.2017A030312009Research Grant of Guangdong Province Key Laboratory of Psychiatric Disorders of China,No.N201904(all to JG).
文摘Wallerian degeneration occurs after peripheral nerve injury and provides a beneficial microenvironment for nerve regeneration.Our previous study demonstrated that ascorbic acid promotes peripheral nerve regeneration,possibly through promoting Schwann cell proliferation and phagocytosis and enhancing macrophage proliferation,migration,and phagocytosis.Because Schwann cells and macrophages are the main cells involved in Wallerian degeneration,we speculated that ascorbic acid may accelerate this degenerative process.To test this hypothesis,400 mg/kg ascorbic acid was administered intragastrically immediately after sciatic nerve transection,and 200 mg/kg ascorbic acid was then administered intragastrically every day.In addition,rat sciatic nerve explants were treated with 200μM ascorbic acid.Ascorbic acid significantly accelerated the degradation of myelin basic protein-positive myelin and neurofilament 200-positive axons in both the transected nerves and nerve explants.Furthermore,ascorbic acid inhibited myelin-associated glycoprotein expression,increased c-Jun expression in Schwann cells,and increased both the number of macrophages and the amount of myelin fragments in the macrophages.These findings suggest that ascorbic acid accelerates Wallerian degeneration by accelerating the degeneration of axons and myelin in the injured nerve,promoting the dedifferentiation of Schwann cells,and enhancing macrophage recruitment and phagocytosis.The study was approved by the Southern Medical University Animal Care and Use Committee(approval No.SMU-L2015081)on October 15,2015.
基金Project supported by Program of National Natural Science Foundation of China(51604128)China Postdoctoral Science Foundation(2017M620279)Key projects of the major Research and Development Program of Jiangxi Province(20171ACE50008)
文摘The magnesium sulfate leaching technology for the ion-absorbed rare earths ore can solve the ammonia pollution problem existing in ammonium sulfate leaching process. However, the leaching capacity of magnesium sulfate is slightly weaker than that of ammonium sulfate, resulting in a bigger consumption of magnesium sulfate. In this paper, the MgSO4-ascorbic acid compound leaching agent had been demonstrated to deal with the ion-absorbed rare earths ore. The ascorbic acid could form a stable coordination with rare earth ions, so that it can strengthen the leaching of ion-exchangeable phase.Moreover, ascorbic acid has a strong reductive property, it can leach the colloidal sediment phase rare earth as well. The present study investigates the effect of the initial pH and the composition of leaching agent on the rare earth leaching. It is determined that the rare earth leaching efficiency is 107.5% under the condition of pH 2.00,0.15 mol/L magnesium sulfate and 1.0 g/L ascorbic acid in leaching agent. In this case, the content of the ion-exchangeable phase and colloidal sediment phase rare earth in the leaching residues are both only 0.02‰. The leaching efficiency of colloid sediment phase rare earth can be 85.7%,so that the Ce partition in the leaching liquor increases to be 5.77%. The magnesium-ascorbic acid compound leaching agent is proposed to be a promising choice to deal with the ion-absorbed rare earths ore, which can realize the efficient leaching, low consumption of MgSO4 and environmentally friendly leaching.
基金carried out in the frame work of the project(2-033-180000-03-0000-85013) funded by Iranian Ministry of Jahade Agriculture, Agricultural Extension, Education and Research Organization
文摘The effects of exogenous ascorbic acid and silicium on leaf fresh weigh, seed yield, photosynthesis, changes of the activities of major antioxidant enzymes, nitrate reductase activity, proline accumulation, chlorophyll content, and fatty acid composition were investigated in salt-stressed canola. A hydroponic pot experiment was conducted based on randomized complete block design, factorial arrangement was used with 16 combinations of salinity stress （0, 100, 200, and 300 mmol L-1 NaC1）, ascorbic acid （0 and 30 mmol L-1）, and silicium （2 and 4 mmol L-1 from potassium silicate） with three replicates. The results showed that salinity significantly decreased leaf area and leaf fresh weight, seed yield, photosynthesis, nitrate reductase activity, chlorophyll content, and seed protein percentage. Conversely, respiration, antioxidant enzymes activity, proline accumulation, and linolenic acid percentage increased due to salt stress. Ascorbic acid application improved photosynthesis and seed yield and mitigated antioxidant enzyme activity. In addition, nitrate reductase activity and chlorophyll a and b were positively affected by ascorbic acid. Regarding silicium application, that was found that leaf area, leaf fresh weight, seed yield and photosynthesis, ascorbate peroxidase activity, nitrate reductase activity, and chlorophyll content increased, while respiration decreased. Furthermore, silicium had not significant effect on antioxidant enzyme activity. In general, ascorbic acid and silicium were involved in the defensive mechanisms against salinity stress and it can be suggested that, ascorbic acid and silicium application had positive effect on canola growth under conditions of salt stress.
基金supported by the National Key Research and Development Project of China(2021YFC2902202,2020YFC1909002)the National Natural Science Foundation of China(51604128)+1 种基金the Youth Jinggang Scholars Program in Jiangxi Province(QNJG2019056)the Cultivation Project of the State Key Laboratory of Green Development and High-value Utilization of Ionic Rare Earth Resources in Jiangxi Province(20194AFD44003)。
文摘The magnesium sulfate(MgSO_(4))-ascorbic acid(Vc)compound leaching technique can extract rare earth elements(REEs)existing in ion-exchangeable phase and colloidal phase from ion-adso rption type rare earth ore through the synergy effect of coordination and reduction,but its reaction process and mechanism remain unclear.In this paper,the coordination-reduction leaching mechanism was analyzed from the perspectives of leaching thermodynamics and kinetics,which provide theoretical guidance for the compound leaching process.In the case of neodymium,about 45%of dissolved neodymium will exist as the complex species of NdVc_(()3(aq))in Nd-Vc-sulfate system.Based on this,it is deduced that the Gibbs free energy of the leaching reaction of ion-exchangeable phase REEs will change to a more negative value through the coordination of REEs cations and Vc anions in the MgSO_(4)leaching process.In addition,the E_(h)-pH diagrams of Ce-SO_(4)^(2-)-H_(2)O and Fe-SO_(4)^(2-)-H_(2)O together with the dissolution experiments confirm that the added Vc initiates the leaching process of colloidal phase REEs through reduction-dissolution reaction.Through the study of leaching kinetics,the leaching of REEs is controlled by diffusion and chemical reaction in the co mpound leaching system since colloidal phase REEs are leached.Therefore,the addition of Vc can shift the leaching equilibrium to a more favorable state and accelerate leaching process.The rare earth leaching efficiency of ion-exchangeable phase and colloidal phase can be effectively improved by increasing the reaction temperature,the conce ntrations of leaching agent and Vc,and the leaching agent acidity.
基金supported by the Key Program of Science and Technology of Zhejiang Province(No.2007C12068)of Chinathe National Natural Science Foundation of China(No.30901002)
文摘Tea polyphenols have been shown to have anticancer activity in many studies.In the present study,we investigated effects of theaflavin-3-3'-digallate(TF3),one of the major theaflavin monomers in black tea,in combination with ascorbic acid(AA),a reducing agent,and(-)-epigallocatechin-3-gallate(EGCG),the main polyphenol presented in green tea,in combination with AA on cellular viability and cell cycles of the human lung adenocarcinoma SPC-A-1 cells.The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT) assay showed that the 50% inhibition concentrations(IC50) of TF3,EGCG,and AA on SPC-A-1 cells were 4.78,4.90,and 30.62 μmol/L,respectively.The inhibitory rates of TF3 combined with AA(TF3+AA) and EGCG combined with AA(EGCG+AA) at a molar ratio of 1:6 on SPC-A-1 cells were 54.4% and 45.5%,respectively.Flow cytometry analysis showed that TF3+AA and EGCG+AA obviously increased the cell population in the G0/G1 phase of the SPC-A-1 cell cycle from 53.9% to 62.8% and 60.0%,respectively.TF3-treated cells exhibited 65.3% of the G0/G1 phase at the concentration of its IC50.Therefore,TF3+AA and EGCG+AA had synergistic inhibition effects on the proliferation of SPC-A-1 cells,and significantly held SPC-A-1 cells in G0/G1 phase.The results suggest that the combination of TF3 with AA or EGCG with AA enhances their anticancer activity.
基金CONICET(PIP-112-201101-00055)ANPCYT(PICT-2012-0141)and Universidad Nacional del Sur(PGI 24/M127)Bahía Blanca,Argentina are acknowledged for financial support.
文摘Cerium-based conversion coatings were formed on AZ91D magnesium alloy by immersion of the substrate in solutions containing Ce(NO_(3))_(3),H_(2)O_(2) and ascorbic acid(HAsc).The characterisation of the films was performed by electrochemical and surface analysis techniques such as SEM,EDS,X-ray diffraction and X-ray photoelectron spectroscopy(XPS).The degree of corrosion protection achieved was evaluated in simulated physiological solution by the open circuit potential monitoring,polarisation techniques and electrochemical impedance spectroscopy(EIS).The presence of HAsc in the conversion solution causes changes in the morphology,adherence and anticorrosive performance of the films.The improvement in the corrosion resistance is closely associated with the corrosion inhibition properties of HAsc.
基金The State Key Development Program(2016YFD0501202)supported this study
文摘Background: Laying hens over 75 weeks of age commonly show great declines in immunity and production performance.It is unclear whether these declines can be relieved by supplementing with ascorbic acid(AA) in feed.Two trials were conducted to investigate the synthesis and metabolism of AA in layers of different ages and the effects of dietary supplemental AA on the performance and the immune and antioxidant statuses of 78 weeks old hens.Methods: In Exp.1,equal numbers(24 hens) of 35 weeks old(Young) and 75 weeks old(Old) layers were fed the same diet without AA supplementation for 4 weeks.In Exp.2,360 healthy 78 weeks old laying hens were randomly assigned to 4 treatments(basal diet supplemented with 0,0.25,0.5,or 1 g AA/kg diet) in an 8-week feeding trial.Results: The old hens tended to have decreased L-gulonolactone oxidase(GLO) synthase activity in the kidney and liver than that of the young hens(P = 0.07 and P = 0.05,respectively).Compared with the young hens,the old hens had lower hepatic antioxidant capacity allowing for the lower thioredoxin(TXN),thioredoxin reductase(TXNR) and cytochrome b5 reductase(CYB5 R) gene expression(P < 0.05),whereas increased sodium-dependent vitamin C transporter(SVCT) 1 expression levels in the ileum and kidney and enhanced splenic and hepatic AA concentrations(P < 0.05).Dietary supplementation with AA significantly decreased GLO enzyme activity but increased splenic AA concentration and anti-bovine serum albumin IgG levels(P < 0.05) and tended to increase CD4+T lymphocyte numbers(P = 0.06) in serum.Supplementation of 0.25 g AA/kg diet significantly increased hepatic total antioxidant capacity(T-AOC,P < 0.05) relative to the control group.Conclusions: Laying hens could synthesize AA in both the kidney and the liver,though the GLO enzyme activities were 100 times greater in kidneys than in livers.The old laying hens had greater absorption and reabsorption capacity and higher AA retention in some tissues that did the young hens.Dietary supplementation of AA can improve the health of old layers by enhancing immunity and antioxidant capacity.
文摘Objective To find out the mechanisms of redifferentiation and reversion of malignant human gastric cancer cells induced by ascorbic acid. Methods Human gastric cancer cells grown in the laboratory were used. The Trypan blue dye exclusion method was used to determine the cell doubling time. The electrophoresis rate and colonogenic potential were the indices used to measure the rate of redifferentiation. The content of malondialdehyde （MDA） was measured using the thiobarbituric acid （TBA） method. The activities of superoxide dismutase （SOD）, catalase （CAT） and the content of H2O2 were evaluated by spectrophotography. Results Six mmol/L ascorbic acid was used as a positive control. Human gastric cancer cells were treated with 75 μm hydrogen peroxide, which alleviated many of the malignant characteristics. For example, the cell surface charge obviously decreased and the electrophoresis rate dropped from 2.21 to 1.10 pm·s^-1·cm^-1 The colonogenic potential, a measure of cell differentiation, decreased 90.2%. After treatment with ascorbic acid, there was a concentration- and time-dependent increase in hydrogen peroxide （H2O2） and the activity of superoxide dismutase （SOD）. However, the activity of catalase （CAT） resulted in a concentration- and time-dependent decrease. SOD and 3-amino- 1,2,4-triazole （AT） exhibited some effects, but there were statistically significant differences between the SOD and AT group and the H2O2 group, Conclusions Ascurbic acid induces growth inhibition and redifferentiation of human gastric cancer cells through the production of hydrogen peroxide.
文摘Lead is a ubiquitous environmental and industrial pollutant that may have toxic effects on the male. Vitamins may protect against toxic effects of lead in the liver and reproductive system, which is confirmed by our initial research. The aim of this study was to further investigate the protective effects of vitamins （ascorbic acid combined with thiamine） on lead acetate （Pb）-induced reproductive toxicities in mice and study the possible mechanisms underlying these effects. Forty-five male mice were randomly divided into 3 groups, 15 mice in each and received daily intragastric administration with control, Pb （20 mg/kg）, and Pb＋vitamins （ascorbic acid of 420 mg/kg＋thiamine of 30 mg/kg） for 6 weeks, respectively. The Pb-treated animals showed significant decreases in the epididymal sperm count and motility compared to the control group, while the Pb＋vitamins group had significant increases for these variables. Moreover, an increasing apoptosis of germinal cells induced by Pb was reduced by vitamin treatment. Pb induced the activation of Caspase-3, Fas/Fas-L and Bcl-2 with elevated levels, and the adaptor protein primarily regulated signaling through Fas and required for Fas-induced apoptosis. In conclusion, ascorbic acid combined with thiamine exhibited protective effect on reproductive system by inhibiting Pb-induced excessive cell apoptosis.
文摘The kinetics of dissolved O_2 reduction and hydrogen evolution reactions on copper surface was studied in naturally aerated and air and O_2-saturated 0.50 mol/L H_2SO_4 solutions using polarization measurements combined with the rotating disc electrode (RDE).The Koutecky-Levich plot indicated that the dissolved O_2 reduction at the copper electrode was an apparent four-electron process.A correlation between the presence of dissolved O_2 and the formation of Cu_2O,confirmed from XRD,was discussed. Ascorbic a...
基金Supported by the Chang Gung Memorial Hospital,No.CMRPG3F1471~2 and No.CMRPG3G0031~3the Ministry of Science and Technology No.MOST106-2314-B-182A-042-34 and No.MOST 107-2314-B-182A-088-MY3
文摘BACKGROUND The current case report describes successful phacoemulsification with the aid of perioperative topical ascorbic acid(AA) in two patients with corneal endothelial disorders to prevent postoperative corneal endothelial decompensation.CASE SUMMARY Two eyes of two patients underwent phacoemulsification with pre-existing corneal endothelial disorders including Fuchs corneal endothelial dystrophy(Patient 1) and endotheliitis(Patient 2). Topical AA was applied to both patients at least one month before and after with a frequency of four times per day. After the surgery, both eyes improved best-corrected visual acuity(BCVA) and there was limited human corneal endothelial cell loss without signs of corneal endothelial decompensation, such as deteriorated BCVA or persistent corneal edema during the follow-up of at least two years.CONCLUSION Perioperative administration of topical AA may be an alternative therapy to the triple procedure in patients expecting to undergo cataract surgery.
基金financial support from the Science and Engineering Research Board(SERB),India(No.ECR/2016/001446)Department of Science and Technology(International Bilateral Cooperation Division)for financial support through"INDO-RUSSIA Project(No.INT/RUS/RFBR/385)"。
文摘Two-dimensional(2 D)titanium carbide(MXene)nanosheets exhibited excellent conductivity,flexibility,high volumetric capacity,hydrophilic surface,thermal stability,etc.So,it has been exploited in various applications.Herein,we report synthesis of mixed phase 2 D MXene as a catalytic material for simultaneous detection of important biomolecules such as ascorbic acid(AA),dopamine(DA)and uric acid(UA).Crystalline structure,surface morphology and elemental composition of mixed phase titanium carbide(Ti-C-T_(x))MXene(T_(x)=-F,-OH,or-O)nanosheets were confirmed by X-ray diffraction(XRD),Raman spectroscopy,high-resolution transmission electron microscopy(HR-TEM),high-re solution scanning electron microscopy(HR-SEM)and Energy-dispersive X-ray spectroscopy(EDS)mapping analysis.Furthermore,Ti-C-T_(x) modified glassy carbon electrode(GCE)was prepared and its electrochemical properties are studied by cyclic voltammetry(CV)and diffe rential pulse voltammetry(DPV).It was found that Ti-C-T_(x) modified GCE(Ti-C-T_(x)/GCE)showed excellent electrocatalytic activity and separated oxidation peaks of important biomolecules such as AA(at 0.01 V),DA(at 0.21 V)and UA(at 0.33 V).Also,Ti-C-T_(x)/GCE sensor is enabled their simultaneous detection in physiological pH from 100 to 1000μM for AA,0.5-50μM for DA and 0.5-4μM&100-1500μM for UA.The limit of detection’s(LOD)was estimated as 4.6μM,0.06μM and 0.075μM for AA,DA and UA,respectively.Moreover,real sample analysis indicated that spiked AA,DA and UA can be determined accurately by Ti-C-T_(x)/GCE with the recovery ratio in the range between 100.5%-103%in human urine samples.The proposed Ti-C-T_(x) modified electrode exhibited good stability,selectivity and reproducibility as an electrochemical sensor for the detection of AA,DA and UA molecules.
基金supported by Key Scientific Research Program in Colleges and Universities of Ministry of Education of China(No.207151)Foundation of Educational Commission of Shnanxi Province of China(No.08JK322)Youth Foundation of Xi'an University of Architecture and Technology(No.QN0620)
文摘A carbon paste electrode modified with electropolymerized fills of isonicotinic acid was developed. The modified electrode shows excellent electrocatalytic activity toward the oxidation of both dopamine （DA） and epinephrine （EP）. Separation of the reduction peak potentials for dopamine and epinephrine was about 357 mV in pH 5.3 phosphate buffer solution （PBS） and the character was used for the detection DA and EP simultaneously. The peak currents increase linearly with DA and EP concentration over the range of 8.0×10^-5 to 7.0×10^-4 mol/L and 5.0×10^-6 to 1.0×10^-4 mol/L with detection limits of 2×10^-5 and 1×10^-6 mol/L, respectively. The interference studies showed that the modified electrode exhibits excellent selectivity in the presence of large excess of ascorbic acid （AA）.
