Fulx-pinning mechanism and activation energy of MgB2 doped with 10 wt % MALIC- ACID has been investigated by measurement of critical current density and resistivity as a function of magnetic fields and temperatures. The field dependence of the critical current density, Jc (B), was analyzed within the collective pinning model. A crossover field, Bsb, from the single vortex to the small vortex bundle-pinning regime was observed. For sintered sample, the temperature dependence of Bsb (T) at low temperature is in good agreement with the δℓ pinning mechanism, i.e., pinning associated with charge-carrier mean free path fluctuation. The activation energy was decreased linearly by increasing magnetic field.

Soil pollution by toxic metals is a serious problem for the environment and is also one of the environmental stresses for higher plants. Zinc as a heavy metal plays an important role in many biochemical functions of plants. However, excess amount of zinc is one of the most important growth limiting factors in ACID soils. In this investigation five day seedlings of Zea mays L. for 12 days, under hydroponic conditions were treated with concentrations of 0, 400 and 600 of zinc sulfate also MALIC ACID and citric ACID 0.32 mM together with zinc concentrations. Then, plants were harvested and dry weight, root and shoot length, Malondialdehyde (MDA), H2O2 content and antioxidant enzyme activity (CAT, APX, GR and GPX) was measured. The results showed that by increasing Zn concentration from 400 to 600 mM, root and shoot dry weight and length were decreased, while MDA, H2O2 content, antioxidant enzyme activity were increased. Also, the present of citric and MALIC ACIDs decreased toxicity effects. Generally, it was concluded that zinc at high concentration induced toxicity effects in Zea mays L. but presece of MALIC and citric ACID decreased toxicity effects in this plant.

Background: Poly-L-MALIC ACID (PLMA) comprises aliphatic polyester polymers with broad applications in pharmaceutical industries. The fungal microorganisms are among the best natural sources recruited to supply L-MALIC ACID (MA) as a precursor of PLMA. In this study, we investigated MA production ability of 7 clinical isolated of the fungus Aureobasidium pullulans. Materials and Methods: Seven clinical isolates of A. pullulans acquired from Westerdijk Fungal Biodiversity Institute were studied, and the isolate with the highest total MA production was selected for the optimization process. We tried to optimize the output by applying different concentrations of CaCO3 in fungus medium (1. 5%, 3%, and 6%) and various incubation temperatures (27° C, 32° C, and 37° C) during 3, 7, and 14 days. Results: Intra-strains variation was significantly strong (P<0. 0001), and the highest production of MA was carried out by the isolate A. pullulans var. melanigenum dH 21931, UTHSC 06-456. The amount of MA produced by this strain was significantly higher in medium with 3% CaCO3 compared with other concentrations of CaCO3 and after 7 days incubation than the other fermentation times (P<0. 05). Although MA production was higher at 27° C, the differences between the investigated various temperatures were not significant (P>0. 05). Conclusion: Overall, we obtained the highest MA production in Sabouraud dextrose agar (SDA) medium with 3% CaCO3 at 27° C after 7 days of incubation. Our study indicated that the fermentation period and CaCO concentration significantly alter MA production in A. pullulans var. melanigenum.

A spectrophotometric study of the kinetics and mechanism of the oxidation of MALIC ACID (Mal) by chromium (VI) catalyzed by 2,2'-bipyridyl (bpy) in aqueous ACIDic medium was conducted in a temperature range of ~298 to 313 K. This reaction was found to be pseudo-first order with respect to Cr(VI) and first order with respect to MALIC ACID. Under the conditions of the pseudo-first order ([Mal]o >> [Cr(VI)]o ), the observed rate constant (kobs) increased with the increase in [H+] and [bpy]. There was a weak negative salt effect. Based on the experimental results, a possible reaction mechanism for this oxidation catalyzed by bpy is proposed. The rate equation derived from this mechanism can explain all the experimental phenomena.

IntroductionFruits are one of the most valuable horticultural products that play an important role in providing of human nutrition and health. This group of agricultural products are perishable due to high content of water, high respiration and transpiration rate, hence, most of them are short life products. In present study, MALIC ACID with different concentrations were used as treatments to protect cell membranes, maintain quality and increase shelf life during the postharvest period in sour cherry fruits. Materials and MethodsSour cherry fruits were selected from a commercial orchard in Mahan city of kerman in 2021 years, after treatment with 0, 2 and 4% MALIC ACID and stored at 1°C with 85% relative humidity for 16 days. Traits such as chilling injury, hydrogen peroxide, lipid peroxidation, ion leakage, antioxidant capacity and antioxidant enzymes including peroxidase, catalase, superoxide dismutase, ascorbate peroxidase were measured. Results and DiscussionThe results showed that the application of MALIC ACID with both concentrations of 2 and 4% and in all studied intervals led to a decrease in chilling injury, hydrogen peroxide, lipid peroxidation, and ion leakage compared to the control samples. On the other hand, in fruits treated with MALIC ACID, the antioxidant capacity and activity of antioxidant enzymes including peroxidase, catalase, superoxide dismutase, and ascorbate peroxidase increased. ConclusionAs a general conclusion, MALIC ACID with a concentration of 4% in all studied intervals had significant effects at a statistical level of 5% on improving the antioxidant activities of cherry fruits during the storage period.

Novel separation methods that are necessary for the purification of biomolecules and carboxylic ACIDs at industries, are expanding. Therefore, these methods should be fast, selective, and easy to scale up. The aqueous two-phase system is an effective separation procedure for the purification of materials. The purification of biomolecules and carboxylic ACIDs is extremely selective by this method and also, the separation process is conducted in one step. This research aimed to investigate the effects of molecular weight of polyethylene glycol, pH, salt concentration, and salt type in polymer/salt aqueous two-phase systems. In this research, purification of MALIC ACID in aqueous two-phase systems containing polyethylene glycol 4000 and 8000 g/mol, different concentration sodium di hydrogen phosphate, diammonium hydrogen phosphate, and di potassium hydrogen phosphate were studied. After investigating the effective factors, the best operation conditions for MALIC ACID extraction was obtained in a system composed of PEG4000, 0. 25 (w/w) sodium di hydrogen phosphate at pH=5. The purification parameters such as partition coefficient of MALIC ACID and yield were achieved 0. 85 and 80%, respectively.

In the present study, the effects of dietary MALIC ACID on growth and intestinal histomorphology of goldfish (Carassius auratus) was investigated. 120 goldfish (mean initial weight 14. 62 ± 0. 92 g) (Mean ± Standard Error) were divided into 4 treatments and 3 replicates. Treatments included different concentrations of MALIC ACID 0 (control), 2. 5, 5 and 10 g/kg diet. Fish feeding was carried out three times a day for 8 weeks. Fish biometry performed every two weeks and at the end of the experiment, six fish per each tank were sampled for histological study of the intestinal tissue. Results showed that there were not significant differences in final weight, percentage of body weight gain, specific growth rate, feed conversion ratio and condition factor between different treatments (P> 0. 05). There were not significant statistical differences in the length of the villi, the diameter of the tunica mascularis and also the number of calyx in the intestinal tract between different treatments (P> 0. 05). The results of the present study showed that the use of MALIC ACID does not affect the growth performance and intestinal histomorphology of goldfish.