Acid Disodium Salt Research Articles

A novel method of rapid detection for heavy metal copper ion via a specific copper chelator bathocuproinedisulfonic acid disodium salt

The extensive usage and production of copper may lead to toxic effects in organisms due to its accumulation in the environment. Traditional methods for copper detection are time consuming and infeasible for field usage. It is necessary to discover a real-time, rapid and economical method for detecting copper to ensure human health and environmental safety. Here we developed a colorimetric paper strip method and optimized spectrum method for rapid detection of copper ion based on the specific copper chelator bathocuproinedisulfonic acid disodium salt (BCS). Both biological assays and chemical methods verified the specificity of BCS for copper. The optimized reaction conditions were 50 mM Tris–HCl pH 7.4, 200 µM BCS, 1 mM ascorbate and less than 50 µM copper. The detection limit of the copper paper strip test was 0.5 mg/L by direct visual observation and the detection time was less than 1 min. The detection results of grape, peach, apple, spinach and cabbage by the optimized spectrum method were 0.91 μg/g, 0.87 μg/g, 0.19 μg/g, 1.37 μg/g and 0.39 μg/g, respectively. The paper strip assays showed that the copper contents of grape, peach, apple, spinach and cabbage were 0.8 mg/L, 0.9 mg/L, 0.2 mg/L, 1.3 mg/L and 0.5 mg/L, respectively. These results correlated well with those determined by inductively coupled plasma-mass spectrometry (ICP-MS). The visual detection limit of the paper strip based on Cu-BCS-AgNPs was 0.06 mg/L. Our study demonstrates the potential for on-site, rapid and cost-effective copper monitoring of foods and the environment.

High-efficiency cleaning technology and lifespan prediction for the ceramic membrane treating secondary treated effluent.

Chemical cleaning is one of the key technical means to control membrane fouling, restore membrane flux and ensure the stable operation of membrane systems. In the experiment, the six most representative chemical cleaning agents for ceramic membranes, such as sulfuric acid (H2SO4), sodium hydroxide (NaOH), sodium hypochlorite (NaClO), ethylenediaminetetraacetic acid disodium salt (EDTA-Na2), sodium dodecyl sulfate (SDS) and nonylphenol polyoxyethylene ether (OP-10), were used as research objects. The cleaning effect of the two-step combined cleaning of chemical cleaning agents on the fouled membrane was systematically investigated. Results showed that the order of the chemical cleaning agent had a significant effect on the cleaning effect. The best chemical cleaning program was determined to be NaClO first and then SDS: the fouled ceramic membrane was soaked in NaClO solution at 0.15% for 2.5 h and further soaked in SDS solution at five times its own critical micelle concentration for 2.5 h. The predicted long-term lifespan of the ceramic membranes was 4.91 years. Scanning electron microscopy-energy spectrum analysis showed that the surface roughness of the cleaned ceramic membrane was slightly higher than that of the new membrane. The contact angle was slightly lower than that of the new membrane.

Reversible Morphology Locking via Metal Infiltration in a Block Copolymer.

Metal infiltration from an acid solution of a metal precursor into the poly(2-vinylpyridine) (P2VP) microdomains of a polystyrene-b-P2VP block copolymer is shown to reduce the uptake of solvent vapor during a subsequent solvent annealing process, locking the morphology of the self-assembled microdomains. The amount of metal, here Pt, incorporated into the P2VP increases with both metal precursor [PtCl4]2- and hydrochloric acid concentrations, reaching 0.83 Pt atom per pyridine unit. The metal is then exfiltrated using a KOH + ethylenediaminetetraacetic acid disodium salt dihydrate (Na2EDTA) complexing solution, which restores solvent uptake and unlocks the morphology. The reversibility of the metal infiltration and morphology locking is demonstrated in a multistage annealing process and is confirmed for Fe as well as Pt. Reversible locking and unlocking of block copolymer microdomain morphologies expand their utility for nanofabrication processes by allowing the morphology to be fixed during subsequent process steps.

The GRAS Salts of Na2SiO3 and EDTA-Na2 Control Citrus Postharvest Pathogens by Disrupting the Cell Membrane.

Sodium silicate (Na2SiO3) and ethylenediaminetetraacetic acid disodium salt (EDTA-Na2) are inorganic salts classified as 'Generally Recognized as Safe' (GRAS) compounds with great advantages in controlling various pathogens of postharvest fruits and vegetables. Here, we determined the median effective concentration (EC50) of Na2SiO3 (0.06%, 0.05%, 0.07% and 0.08%) and EDTA-Na2 (0.11%, 0.08%, 0.5%, and 0.07%) against common pathogens affecting postharvest citrus fruit, including Penicillium digitatum, Penicillium italicum, Geotrichum citri-aurantii, and Colletotrichum gloeosporioides. Na2SiO3 and EDTA-Na2 treatments at the EC50 decreased the spore germination rate, visibly disrupted the spore cell membrane integrity, and significantly increased the lipid droplets (LDs) of the four postharvest pathogens. Moreover, both treatments at EC50 significantly reduced the disease incidence of P. italicum (by 60% and 93.335, respectively) and G. citri-aurantii (by 50% and 76.67%, respectively) relative to the control. Furthermore, Na2SiO3 and EDTA-Na2 treatment resulted in dramatically lower disease severity of the four pathogens, while also demonstrating no significant change in citrus fruit quality compared with the control. Therefore, Na2SiO3 and EDTA-Na2 present a promising approach to control the postharvest diseases of citrus fruit.

Curcumin and Its Supramolecular Complex with Disodium Glycyrrhizinate as Potential Drugs for the Liver Fluke Infection Caused by Opisthorchis felineus.

Opisthorchiosis is a parasitic liver disease found in mammals that is widespread throughout the world and causes systemic inflammation. Praziquantel remains the drug of choice for the treatment of opisthorchiosis, despite its many adverse effects. An anthelmintic effect is attributed to the main curcuminoid of Curcuma longa L. roots-curcumin (Cur)-along with many other therapeutic properties. To overcome the poor solubility of curcumin in water, a micellar complex of curcumin with the disodium salt of glycyrrhizic acid (Cur:Na2GA, molar ratio 1:1) was prepared via solid-phase mechanical processing. In vitro experiments revealed a noticeable immobilizing effect of curcumin and of Cur:Na2GA on mature and juvenile Opisthorchis felineus individuals. In vivo experiments showed that curcumin (50 mg/kg) had an anthelmintic effect after 30 days of administration to O. felineus-infected hamsters, but the effect was weaker than that of a single administration of praziquantel (400 mg/kg). Cur:Na2GA (50 mg/kg, 30 days), which contains less free curcumin, did not exert this action. The complex, just as free curcumin or better, activated the expression of bile acid synthesis genes (Cyp7A1, Fxr, and Rxra), which was suppressed by O. felineus infection and by praziquantel. Curcumin reduced the rate of inflammatory infiltration, whereas Cur:Na2GA reduced periductal fibrosis. Immunohistochemically, a decrease in liver inflammation markers was found, which is determined by calculating the numbers of tumor-necrosis-factor-positive cells during the curcumin treatment and of kynurenine-3-monooxygenase-positive cells during the Cur:Na2GA treatment. A biochemical blood test revealed a normalizing effect of Cur:Na2GA (comparable to that of curcumin) on lipid metabolism. We believe that the further development and investigation of therapeutics based on curcuminoids in relation Opisthorchis felineus and other trematode infections will be useful for clinical practice and veterinary medicine.

Three-Dimensional-Printed Device for In Situ Monitoring of an Organic Redox-Flow Battery via NMR/MRI.

A mini organic redox-flow battery pluggable on the basis of a high-resolution nuclear magnetic resonance probehead has been conceived and built mainly by 3D printing. This device allows the realization of all modern spectroscopy experiments as well as imaging experiments. It has been tested for the real-time monitoring of redox cycling of 9,10-anthraquinone-2,7-disulfonic acid disodium salt (2,7-AQDS) in acidic conditions, which has revealed the preponderant role of dimerization in the processes of oxidation and reduction. Determination of the thermodynamic properties of homo- and heterodimer formation through quantum chemical, multilevel modeling workflows confirms our hypotheses about the molecular processes occurring during charge and discharge.

Cleaning iron rust compounds from cotton textiles: application to Qing Dynasty armor

A composite structure consisting of cotton fabric and iron sheet was widely used in Qing Dynasty armor. Due to iron sheet corroding easily, the surfaces of cotton fabric were covered with numerous rust compounds, which has a significant negative impact on the relics. In this paper, by taking Qing Dynasty armor relics as the research object, the cleaning process was reported for cotton fabrics stained with corrosion products. Using an orthogonal experiment, rust stained model samples were used to explore a specialized and efficient cleaning process. Results show that the cleaning reagents, including ascorbic acid (mass fraction 10.0 g/L), ethylenediaminetetraacetic acid disodium salt (EDTA-2Na, mass fraction 10.0 g/L), and the surfactant composed of 70% rhamnolipid and 30% alkyl glycoside (mass fraction 8.0 g/L), could fully exert a synergistic effect. After treatment, the color difference (ΔE) value between the cleaned sample and the unstained sample is only 3.81. A series of comprehensive experimental results demonstrate that the cleaning procedure is effective and safe. There are almost no rust compounds and cleaning reagent residues, and no damage to cotton fiber. The reported wet cleaning process, aided by soft bristle brush, achieved good cleaning results, indicating that the process can be used to clean rust stain pollutants in Qing dynasty cotton armor.

Limiting Pink Discoloration in Cooked Ground Turkey in the Absence or Presence of Sodium Tripolyphosphate Produced from Presalted and Stored Raw Ground Breasts.

The effects of pink inhibiting ingredients (PII) to eliminate the pink color defect in cooked turkey breast produced from presalted and stored raw ground turkey in the absence or presence of sodium tripolyphosphate (STP) were examined. Ground turkey breast was mixed with 2% sodium chloride and vacuum packaged. After storage for 6 d, ten PII were individually incorporated without or with added STP (0.5%) as follows: none (control), citric acid (CA; 0.1%, 0.2%, 0.3%), calcium chloride (CC; 0.025%, 0.05%), ethylenediaminetetraacetic acid disodium salt (EDTA; 0.005%, 0.01%), and sodium citrate (SC; 0.5%, 1.0%). Treatments were cooked at a fast or slow cooking rate, cooled, and stored before analysis. All PII tested were capable of lowering inherent pink color compared to the control (No STP: CIE a* pooled day reduction of 23.0%, 5.2%, 12.6%, and 12.6% for CA, CC, EDTA, and SC, respectively; STP: reduction of 21.5%, 17.4%, 6.0%, and 18.2% for CA, CC, EDTA, and SC, respectively). For samples without STP, fast cooking rate resulted in higher CIE a*. However, slow cooking resulted in more red products than fast cooking when samples included STP. Presalting and storage of ground turkey caused the pink discoloration in uncured, cooked turkey (CIE a* 6.24 and 5.12 for without and with STP). This pink discoloration can be decreased by inclusion of CA, CC, EDTA, or SC, but incorporation of CA decreased cooking yield. In particular, the addition of SC may provide some control without negatively impacting the cooking yield.

Reduction of hepatotoxicity of nimesulide in mechanochemically obtained composition with disodium salt of glycyrrhizic acid

Nimesulide (NIM) is a nonsteroid anti-inflammatory drug which acts as a selective cyclooxygenase 2 inhibitor and is widely used for acute pain treatment. In medical practice, a large amount of data has been collected describing the effect of NIM on the body, while a hepatotoxic side effect of the drug has been found. The exact mechanisms of such NIM-induced hepatotoxicity largely remain unknown but likely involve the intermediate reaction of its metabolism. Reduction of the hepatotoxic side effect of NIM is an actual problem for pharmacology. The aim of the present research was to evaluate the hepatotoxicity of the mechanochemically obtained composition of NIM with glycyrrhizic acid disodium salt (Na2GA) compared to pure NIM and a physical mixture of NIM with Na2GA. Material and methods. CD-1 mice were orally administered for 14 days: 1 group – mechanochemical composition NIM/Na2GA (1:10, m/m) at a dose of 1650 mg/kg; 2 group – physical mixture of NIM with Na2GA (1:10, m/m) at a dose of 1650 mg/kg; 3 group – pure NIM at a dose of 600 mg/kg (which pharmacokinetically corresponds to 1650 mg/kg of NIM/Na2GA); 4 group – vehicle (distilled water). The liver damage was assessed using histological studies and enzymatic activity of the alanine aminotransferase and aspartate aminotransferase in blood serum. Results. Histological analysis did not detect any changes in the liver of NIM/Na2GA-treated animals in comparison with a water-treated group. On the opposite, NIM given alone or as a physical mixture with Na2GA induced severe hepatotoxicity in experimental mice. Biochemical analysis of the blood serum revealed that mechanochemical NIM/Na2GA composition significantly reduced activity of the alanine aminotransferase (about 1.5 times) and aspartate aminotransferase (1.3 times) as compared with the pure NIM. Conclusions. The results obtained indicate a high potential for the practical application of the NIM/Na2GA mechanochemical composition.

Synthesis and characterization of sulfonated polytriazoles utilizing 1,4‐bis(4‐azido‐2‐(trifluoromethyl)phenoxy)benzene for the proton exchange membrane applications

AbstractThe aromatic hydrocarbon‐based sulfonated polytriazoles have a reputation as a high‐performing polymer because of their excellent properties. This work demonstrates the synthesis of a new semi‐fluorinated diazide monomer, that is, 1,4‐bis(4‐azido‐2‐(trifluoromethyl)phenoxy)benzene (BATFB), and exploiting this compound a series of aromatic hydrocarbon‐based semi‐fluorinated sulfonated polytriazoles (BABPSSH‐60, −70, −80, −90) was synthesized utilizing the Cu(I)‐induced “click” cycloaddition polymerization reaction along with the sulfonated diazide monomer, 4,4′‐diazido‐2,2′‐stilbenesulfonic acid disodium salt tetrahydrate (DASSA) and the terminal dialkyne monomer, 4,4′‐(propane‐2,2′‐diyl)bis((prop‐2‐ynyloxy)benzene) (BPAAL). The structural analysis of those copolymers was completed by the FTIR and the NMR (1H and 13C) spectroscopic methods. Further, the degree of sulfonation (DS) and the ion exchange capacity (IEC) values of the copolymers were confirmed using the 1H NMR spectrums. They are readily soluble in respective solvents, and a light yellowish membrane was obtained using the solution casting procedure. These membranes demonstrated admissible mechanical and thermal stabilities, balanced water absorption properties, and reasonable chemical stability. The surface phase (SAXS, AFM) and bulk phase (TEM) morphological analysis proved the well‐separated phase morphology. The BABPSSH‐90 displayed a proton conductivity of 104 mS cm−1 at 90.

Cost-Effective Preparation of Gold Tailing-Based Aerogels for Efficient Adsorption of Copper Ions from Wastewater

Water pollution caused by heavy metal ions has attracted worldwide attention. In this work, gold tailings were used as raw materials and the sol–gel method combined with the atmospheric pressure drying method were used to achieve the low-cost preparation of a silica aerogel. (3-Aminopropyl) triethoxysilane (APTES), ethylenediaminetetraacetic acid disodium salt (EDTA-2Na), and chitosan were used to modify the silica aerogel, which was then used as an adsorbent for the adsorption of copper ions in wastewater. The adsorbent type, adsorption time, copper ion concentration, and pH value were investigated as variables to explore the best adsorption conditions. The adsorption mechanism was also elaborated on. The crystal structure, surface morphology, surface functional groups, chemical composition, and specific surface area of the aerogels and the modified aerogels were characterized by various physiochemical characterizations such as XRD, SEM, FT-IR, XRF, and BET. The results showed that the prepared silica aerogel contained 91.1% SiO2, mainly amorphous SiO2, and amino and carboxyl groups. Other functional groups were successfully grafted onto the silica aerogels. The original silica aerogels and modified silica aerogels had a large specific surface area, total pore volume, and pore diameter. When copper ions were adsorbed by the chitosan-modified silica aerogels, the adsorption capacity of the copper ions was the highest (33.51 mg/g) under the conditions of a copper ion concentration of 100 mg/L, a pH value of 7, and an adsorption time of 2 h. The adsorption of Cu2+ was mainly due to the ion exchange and electrostatic gravity.

The effects of Pt cocatalyst particle size on charge transfer kinetics in dye-sensitized SrTiO3 photocatalysts for hydrogen evolution studied by time-resolved emission/absorption spectroscopy

Dye-sensitized H2 evolution systems were constructed from Pt-loaded SrTiO3 and Ru(II) complex photosensitizers as building blocks, and the impact of the Pt cocatalyst was investigated. In the presence of a stronger electron donor (sodium ascorbate), SrTiO3 loaded with larger Pt particles showed higher activity. On the other hand, the sample having smaller Pt particles gave higher activity in the presence of a weaker electron donor (ethylenediaminetetraacetic acid disodium salt dihydrate). Time-resolved emission/absorption measurements revealed that the larger Pt particles facilitated electron injection from the excited Ru sensitizer to Pt/SrTiO3, while the smaller one improved charge carrier separation by suppressing the back electron transfer reaction from Pt/SrTiO3 to the oxidized sensitizer. These results show that the cocatalyst particle size can affect the kinetics of the electron injection and carrier separation processes. Judicious choice of the Pt particle size can therefore improve the H2 evolution activity in accordance with the reaction system.

Size dependence of magnetic properties of Fe, Co and Ni nanoparticles prepared by the chemical-metallurgical method using surfactants

The present study focuses on the synthesis of Fe, Co and Ni nanoparticles (NPs) by the chemical-metallurgical method with surfactant additives at the precipitation stage. The effect of surfactant additives on the dispersion, morphology and magnetic properties of the Fe, Co and Ni NPs was studied. The size characteristics of the NPs were measured by scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, and the Brunauer–Emmett–Teller method. Sodium dodecyl sulfate (SDS) and ethylenediaminetetraacetic acid disodium salt (EDTA) were used as surfactants in this study. Application of SDS and EDTA amounting to 0.1 wt% yielded an increase of 1.5–3 times the specific surface area of the reduced NPs. No surfactant traces were found in the reduced samples according to energy dispersive X-ray analysis. The mechanism of surfactant action is proposed. The surfactants reduce the critical radius of hydroxide clusters and prevent their growth and coagulation. The use of more dispersed hydroxides as precursors leads to the formation of NPs with a smaller particle size. The NPs with a diameter close to the critical size of the single-domain state for each material were obtained due to application of the surfactants. It was found that the saturation magnetization values of the Fe, Co and Ni NPs synthesized using surfactants are close to the values of micron-sized samples. This makes them suitable for many applications in mechanical engineering and technological industries.

Rare earth complexes chemiluminescence catalyzed by gold nanoparticles for fast sensing of Tb3+ and Eu3+

Developing multiplex sensing technique is of great significance for fast sample analysis. However, the broad emissions of most chemiluminescence (CL) luminophores make the multiplex CL analysis be difficult. In this work, a simple and sensitive CL analytical method has been developed for the simultaneous determination of Tb3+ and Eu3+ thanking to their narrow band emission. The technique was based on a mixed CL system of periodate (IO4−)-hydrogen peroxide (H2O2)-rare earth complexes, in which the reactive oxygen species (ROSs) especially singlet oxygen (1O2) can transfer its energy to the complex of Tb3+/Eu3+-ethylenediaminetetraacetic acid disodium salt (EDTA) and then produce the characteristic emissions of Tb3+ and Eu3+ without cross-interference. The further experiment found that the CL emissions of Tb3+ and Eu3+ could be catalyzed by the gold nanoparticles (AuNPs) via enhancing the yield of 1O2. The CL intensities of Tb3+ (at 490 nm) and Eu3+ (at 620 nm) increased linearly with concentration of Tb3+ and Eu3+. After the optimization of the CL sensing conditions, the limits of detection (LOD) were 5.0 × 10−9 mol/L and 8.0 × 10−7 mol/L for Tb3+ and Eu3+, respectively. Finally, the method has been applied for measuring the contents of Tb3+ and Eu3+ in leaching solution of mine sample and Tb3+/Eu3+-contained nanomaterials with satisfactory results. The present system provides a new CL technique for multiplex sensing with simplicity and high sensitivity.

Micronucleus test using formalin-fixed rat glandular stomach and colon

BackgroundGenotoxicity in tissues other than hematopoietic tissues, such as the liver and gastrointestinal (GI) tract, is an important focus in the risk assessment of chemicals in humans. We previously developed a rat micronucleus test for the GI tract, which is the first contact tissue where chemicals are introduced into the body through oral exposure. Target cells were obtained from fresh tissue samples by ethylenediaminetetraacetic acid disodium salt (EDTA) treatment. As an improvement to this method, we have used formalin-fixed tissues instead of fresh tissues; this approach can be used for tissues that are sampled from other toxicological tests and that are archived for several years. This new method can be used for examining micronucleus induction retrospectively when needed. In the present study, we compared the performance of the EDTA method and the new method with formalin-fixed tissues (formalin-fixation method).ResultsHistological examination showed that both the EDTA and formalin-fixation methods could be used for collecting cells located in or above the proliferative zone of the GI tract tissues of rats. In addition, the collected cells were similar in shape. We conducted micronucleus tests with rat GI tract tissues by the two methods using model chemicals, which were used as positive control chemicals (a combination of diethylnitrosamine, 1,2-dimethylhydrazine dihydrochloride, and potassium bromate). The two methods showed similar results. We additionally evaluated the aging effect of tissues stored in formalin fixative. The results showed that 1 year of storage did not affect the frequency of micronucleated cells.ConclusionThe equivalence of the EDTA and formalin-fixation methods was confirmed, and micronucleus analysis was possible up to at least 1 year after formalin fixation of the GI tract, indicating that the formalin-fixation method is valuable for the rat GI tract micronucleus test.

Detection of human annexin A1 as the novel N-terminal tag for separation and purification handle

BackgroundSeveral fusion tags for separation handle have been developed, but the fused tag for simply and cheaply separating the target protein is still lacking.ResultsSeparation conditions for the human annexin A1 (hanA1) tagged emerald green fluorescent protein (EmGFP) in Escherichia coli were optimized via precipitation with calcium chloride (CaCl2) and resolubilization with ethylenediamine tetraacetic acid disodium salt (EDTA-Na2). The HanA1-EmGFP absorbing with other three affinity matrix was detected, only it was strongly bound to heparin Sepharose. The separation efficiency of the HanA1-EmGFP was comparable with purification efficiency of the His6-tagged HanA1-EmGFP via metal ion affinity chromatography. Three fluorescent proteins for the EmGFP, mCherry red fluorescent protein and flavin-binding cyan-green fluorescent protein LOV from Chlamydomonas reinhardtii were used for naked-eye detection of the separation and purification processes, and two colored proteins including a red protein for a Vitreoscilla hemoglobin (Vhb), and a brown protein for maize sirohydrochlorin ferrochelatase (mSF) were used for visualizing the separation process. The added EDTA-Na2 disrupted the Fe–S cluster in the mSF, but it showed little impact on heme in Vhb.ConclusionsThe selected five colored proteins were efficient for detecting the applicability of the highly selective hanA1 for fusion separation and purification handle. The fused hanA1 tag will be potentially used for simple and cheap affinity separation of the target proteins in industry and diagnosis.

The SEM and TEM study on the structure of organic scaffold (conchix) isolated from Mytilus edulis L. mussel shells

Demineralised shell of marine molluscs represents an scaffold matrix or conchix and a promising mineral-free biomaterial. The purpose of this work was to study the microstructure of the demineralized shell of the mussel Mytilus edulis L. – an organic matrix isolated with various decalcified reagents – a solution hydrochloric acid HCl and a solution of ethylenediaminetetraacetic acid disodium salt Na2-EDTA. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used as experimental methods in this study. It is shown that the chemical nature of the demineralising reagent determines the structural features of the studied conchix samples, their three layers – periostracum, prismatic layer and nacreous layer in particular. Treatment of mussel shells with HCl solution to remove calcium carbonate leads to partial destruction of the biopolymer structure of the binding organic matrix of mussel shells. Gentle treatment of mussel shells with EDTA solution ensures the preservation of the native structure of the organic matrix. This mineral-free biopolymer has high potential for using in food industry and biomedical applications.

A Color-Changeable “Pearl” for Visually Displaying Chemical Complexation Reactions

An experimental design by combining hydrogel and ethylenediaminetetraacetic acid disodium salt (EDTA) for visually displaying chemical complexation reactions is developed. The Na+ ions on the α-l-guluronic acid (G) unit of the sodium alginate molecule undergo an ion exchange with a divalent cation, so that the G units are stacked to create a cross-linked network, forming a hydrogel. EDTA is inserted into the as-prepared hydrogel, producing transparent hydrogel microspheres containing EDTA, which are considered to be color-changeable pearls on the basis of the chelation of EDTA when reacting with several metal ions. By using different stability constants of the same typed coordination complexes, the color of pearls is changeable. The process and mechanism of the complex reaction are investigated by using elemental mapping, Fourier transform infrared reflection (FTIR) and Raman spectra. Moreover, all the instruments and chemicals for this experiment are included in one single portable experimental kit. The kit is small, easy to carry, cheap, and safe, and it enables easy display of related chemical reactions. By using the developed kit, the students’ hands-on experience can be improved. The experimental operation is simple, green, safe, and interesting, which enables the engineering of color-changeable pearls to be broadly used including the chemical experiment courses in universities, experimental teaching in schools, and the chemical popularization activities for the public.

Purification of Extracellular Protease from Staphylococcus simulans QB7and Its Ability in Generating Antioxidant and Anti-inflammatory Peptides from Meat Proteins

Proteases, especially microbial proteases, are widely used in food processing. The purpose of this study was aimed to purify an extracellular protease produced by the strain Staphylococcus simulans QB7 and to evaluate its ability in hydrolyzing meat proteins and generating antioxidant and anti-inflammatory peptides. The optimal conditions for producing the enzyme were as follows: inoculum ratio, 10%; initial pH, 6.5; temperature, 32 °C; incubation time, 36 h; and rotation speed, 160 rpm. The protease had a molecular weight of approximately 47 kDa, possessing the optimal activity at 50 °C, pH 7.0, The protease was stable at pH 4.0-8.0 and 30-60 °C, and the activity was improved by Na+, Mg2+, Ca2+, and Zn2+ ions, whereas it was inhibited by Cu2+, Co2+, Fe3+, Ba2+, Fe2+, β-M, and ethylene diamine tetraacetic acid disodium salt (EDTA). The protease could effectively hydrolyze meat proteins, and the generated hydrolysate could significantly inhibit tumor necrosis factor-alpha (TNFα)-induced oxidative stress, including superoxide and malondialdehyde levels and inflammation (vascular adhesion molecule-1 [VCAM-1] and cyclooxygenase 2 [COX2)) in human vascular EA.hy926 cells. The present findings support the ability of S. simulans QB7 protease in generating antioxidant and anti-inflammatory peptides during the fermentation of meat products.

Highly efficient hydrogen evolution from formic acid using B, N co-doped carbon-supported Pd nanoparticles

A facile novel B, N co-doped carbon was fabricated by high-temperature pyrolysis of a mixture of ethylenediamine tetraacetic acid disodium salt and boric acid, on which Pd nanoparticles were loaded to synthesize highly efficient Pd/BNC catalyst for dehydrogenation of formic acid. The type and content of N are regulated by the doping of B elements in carbon materials. The high content of N and B doping provides more anchor sites for Pd and strengthens the interaction between the support and Pd nanoparticles, thus forming highly dispersed Pd nanoparticles and regulating the electronic property of Pd. Therefore, the obtained Pd/BNC catalyst displayed enhanced performance (TOF = 2760 h−1) and a lower activation barrier (31.84 kJ/mol). Furthermore, the catalyst also exhibited wonderful cycling stability for hydrogen evolution from formic acid.