OBJECTIVETo study the influence of particle size and morphology on zinc cation adsorption by hydroxyapatite (HA) and dentifrice containing HA.

METHODSFour HAs with different particle sizes and morphologies, HA-containing dentifrice and blank dentifrice were prepared into suspensions of serial concentrations. Zinc ion solutions with an initial concentration of 10 mg/L was mixed with the suspensions and kept for 24 h for adsorption reaction. The zinc ion concentration in the supernatant was measured by inductively coupled plasma emission spectrometer and the sorption rate of zinc ion was calculated.

RESULTSHA and HA-containing dentifrice with various particle sizes and morphologies were all capable of absorbing zinc ions from simulated waste water, and the adsorption rate of HA-containing dentifrice was 3%-10% higher than that of HA. HA with a particle size of 12 µm and a spherical morphology showed the strongest adsorption ability, followed by short bar-shaped HA with a particle size of 30 µm. Both Langmuir and Freundlich equation could simulate the sorption processes of HA dentifrice, while only Langmuir equation could simulate the sorption processes of HA.

CONCLUSIONIncorporation of HA in dentifrice can enhance zinc ion adsorption capacity of the material. The particle size and morphology of HA both affect the adsorption of zinc ions, and 12-µm HA particle with a spherical morphology has the best adsorption ability.

Adsorption ; Dentifrices ; chemistry ; Durapatite ; chemistry ; Particle Size ; Solutions ; Zinc ; chemistry

The coordination compound of L-hydroxyproline (Hyp)-Zn (II) was synthesized with Hyp and zinc sulfate as raw materials in water medium, coordination Synthesizing Mechanism and Antioxidant Activity of Hyp-Zn(II) coordination compound has been researched. Compared with Hyp, the infrared spectrogram of Hyp-Zn (II) coordination compound emerge a new absorption peak at 1100 cm(-1). Conclusion could be obtained that there exists a coordination effect between Hyp and ZnSO4; TG and DSC curve of Hyp and Hyp-Zn(II) coordination compound were analysed. Compared with Hyp, the peak of Hyp-Zn(II) disappear at 290 degrees C and 375 degrees C. This phenomenon confirmed the front conclusion; At the NMR graph of Hyp-Zn(II) coordination compound, the disappearance of the alpha-carboxyl-hydrogen and alpha-hydroxyl-hydrogen's peak at 3.5-3.9 ppm could indicate that combination's position of Hyp is alpha-carboxyl and alpha-hydroxyl; Structure of Hyp-Zn(II) coordination compound were exosyndrome by the Atomic Force microscopy. It is showed that centr-atom Zn(II) was surrounded by several Hyp at Hyp-Zn(II) coordination compound's phase diagram; The proportion of Hyp-Zn(H) coordination compound was determined by dialysis experiment, the proportion is 4:1; Above-mentioned determination and exosyndrome indicated that the molecular formula of Hyp-Zn (II) coordination compound is Zn(Hyp)4.H2O. The results indicated that the Hyp-Zn(II) coordination compound can inhibit hydroxyl free radicals of Zn(II), and the Percentage of Inhibition is 75.5%; the total antioxidant activities of Hyp-Zn(II) coordination compound is 80.167 u/mL, the anti-superoxide activities of Hyp-Zn (II) coordination compound is 53.19 u/mL.
Antioxidants ; chemistry ; Drug Compounding ; Hydroxyproline ; chemistry ; Zinc Sulfate ; chemistry

The effects of reaction temperature, ethanol concentration and weight hourly space velocity (WHSV) on the ethylene production from ethanol dehydration using zinc, manganese and cobalt modified HZSM-5 catalyst were investigated by response surface methodology (RSM). The results showed that the most significant effect among factors was reaction temperature and the factors had interaction. The optimum conditions were found as 34.4% ethanol concentration, 261.3 0 degrees C of reaction temperature and 1.18 h(-1) of WHSV, under these conditions the yield of ethylene achieved 98.69%.
Catalysis ; Cobalt ; chemistry ; Dehydration ; Ethanol ; chemistry ; Ethylenes ; chemistry ; metabolism ; Manganese ; chemistry ; Zeolites ; chemistry ; Zinc ; chemistry

In the present research, molecular simulation and quantum chemistry calculations were combined to investigate the thermal stability of three kinds of insulin aggregations and the effect of Zn (II) ion coordination on these aggregations. The results of molecular simulation indicated that the three insulin dimers in the same sphere closed hexamer had synergistic stability. It is the synergistic stability that enhances the structural and thermal stability of insulin, preserves its bioactivity during production, storage, and delivery of insulin formulations, and prolongs its halflife in human bodies. According to the results of quantum chemistry calculations, each Zn (II)-N (Im-insulin) bond energy can reach 73.610 kJ/mol for insulin hexamer and 79.907 kJ/mol for insulin tetramer. However, the results of Gibbs free energy changes still indicats that the coordination of zinc (II) ions is unfavorable for the formation of insulin hexamer, because the standard Gibbs free energy change of the coordinate reaction of zinc (II) ions associated with the formatting insulin hexamer is positive and increased.
Insulin ; chemistry ; metabolism ; Molecular Dynamics Simulation ; Protein Stability ; Zinc ; chemistry

Antibiotics are playing an increasingly important role in clinical antibacterial applications. However, their abuse has also brought toxic and side effects, drug-resistant pathogens, decreased immunity and other problems. New antibacterial schemes in clinic are urgently needed. In recent years, nano-metals and their oxides have attracted wide attention due to their broad-spectrum antibacterial activity. Nano-silver, nano-copper, nano-zinc and their oxides are gradually applied in biomedical field. In this study, the classification and basic properties of nano-metallic materials such as conductivity, superplasticity, catalysis, and antibacterial activities were firstly introduced. Secondly, the common preparation techniques, including physical, chemical and biological methods, were summarized. Subsequently, four main antibacterial mechanisms, such as cell membrane, oxidative stress, DNA destruction and cell respiration reduction, were summarized. Finally, the effect of size, shape, concentration and surface chemical characteristics of nano-metals and their oxides on antibacterial effectiveness and the research status of biological safety such as cytotoxicity, genotoxicity and reproductive toxicity were reviewed. At present, although nano-metals and their oxides have been applied in medical antibacterial, cancer treatment and other clinical fields, some issues such as the development of green preparation technology, the understanding of antibacterial mechanism, the improvement of biosafety, and the expansion of application fields, require further exploration.
Oxides/chemistry* ; Metal Nanoparticles/chemistry* ; Anti-Bacterial Agents/chemistry* ; Zinc ; Copper

The wide use of ZnO and CuO nanoparticles in research, medicine, industry, and other fields has raised concerns about their biosafety. It is therefore unavoidable to be discharged into the sewage treatment system. Due to the unique physical and chemical properties of ZnO NPs and CuO NPs, it may be toxic to the members of the microbial community and their growth and metabolism, which in turn affects the stable operation of sewage nitrogen removal. This study summarizes the toxicity mechanism of two typical metal oxide nanoparticles (ZnO NPs and CuO NPs) to nitrogen removal microorganisms in sewage treatment systems. Furthermore, the factors affecting the cytotoxicity of metal oxide nanoparticles (MONPs) are summarized. This review aims to provide a theoretical basis and support for the future mitigating and emergent treatment of the adverse effects of nanoparticles on sewage treatment systems.
Wastewater/toxicity* ; Sewage/chemistry* ; Zinc Oxide/chemistry* ; Waste Disposal, Fluid ; Nanoparticles/chemistry* ; Metal Nanoparticles/chemistry* ; Nitrogen/metabolism* ; Water Purification

Zinc-finger proteins have been widely studied due to their highly conserved structures and DNA-binding specificity of zinc-finger domains. However, researches on the zinc-finger proteins from microorganisms, especially those from prokaryotes, are still very limited. This review focuses on the latest progress on microbial zinc-finger proteins, especially those from prokaryotes and the application of artificial zinc-finger proteins in the breeding of robust strains. Artificial zinc-finger proteins with transcriptional activation or repression domain can regulate the global gene transcription of microbial cells to acquire improved phenotypes, such as stress tolerance to heat, ethanol, butanol, and osmotic pressure. Using the zinc-finger domain as DNA scaffold in the construction of enzymatic system can enhance the catalytic efficiency and subsequently the production of specific metabolites. Currently, zinc-finger domains used in the construction of artificial transcription factor are usually isolated from mammalian cells. In the near future, novel transcription factors can be designed for strain development based on the natural zinc-finger domains from different microbes, which may be used to regulate the global gene expression of microbial cells more efficiently.
Bacteria ; metabolism ; DNA ; chemistry ; Protein Engineering ; Transcription Factors ; chemistry ; Transcriptional Activation ; Zinc Fingers

Thermogravimetry (TG), TG-MS, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM)-energy dispersive spectrometer(EDS) were adopted to investigate the pyrolysis characteristics of calamina. According to the findings of the qualitative and quantitative studies on the changes in the content of relevant elements, the whole shape, the functional groups, and the volatile components of calamina before and after being pyrolyzed, the 200-360, 580-750 degrees C were two sensitive temperature ranges related to the changes in effective component during calamina processing. Thermal weight loss was observed for ZnCO3, Zn(OH)2 and ZnCO3-2Zn(OH)2-H2O under 200-360 degrees C and for CaCO3 under 580-750 degrees C. The results of studies on chemical reaction kinetics showed good linear relations. This experiment integrated relevant methods and theories of physical chemistry and science of traditional Chinese medicine processing, and interpretes calamina processing techniques and mechanism, in order to provide a good example for modem studies on other traditional Chinese medicine processing.
Drug Combinations ; Drug Compounding ; methods ; Ferric Compounds ; chemistry ; Kinetics ; Temperature ; Zinc Oxide ; chemistry

OBJECTIVEThe aim of this study is to analyze the processing mechanism of calamine.

METHODXRD, TEM and IR were adopted to analyze the structures and the components of original and calcined calamine. Their antibacterial activities were also determined.

RESULTThe results indicated that zinc carbonate in original calamine was decomposed into zinc oxide after processing at 700 degrees C for 1 hour using original calamine of 40 mesh, and the particle size was smaller than before processing. All of ZnO, ZnCO3 and Zn5 (CO3) 2 (OH) 6 had antibacterial activitives.

CONCLUSIONOriginal calamine is deposed to ZnO after being calcined for 1 h at 700 degrees C and wet milling. The content of ZnO and antibacterial activity of calcined calamine are better than those of original calamine, moreover, the particle size diminishes and become dimensional uniformity, and the contents of dissolved impurities is decreased. The antibacterial activitives of original and calcined calamine are decided by zinc.

Anti-Bacterial Agents ; chemistry ; pharmacology ; Bacteria ; drug effects ; Drug Combinations ; Ferric Compounds ; chemistry ; pharmacology ; Particle Size ; Zinc Oxide ; chemistry ; pharmacology

In order to investigate the effects of pyrolysis conditions on bio-oil production from biomass in molten salt, experiments of biomass pyrolysis were carried out in a self-designed reactor in which the molten salt ZnCl2-KCl (with mole ratio 7/6) was selected as heat carrier, catalyst and dispersion agent. The effects of metal salt added into ZnCl2-KCl and biomass material on biomass pyrolysis were discussed, and the main compositions of bio-oil were determined by GC-MS. Metal salt added into molten salt could affect pyrolysis production yields remarkably. Lanthanon salt could enhance bio-oil yield and decrease water content in bio-oil, when mole fraction of 5.0% LaCl3 was added, bio-oil yield could reach up to 32.0%, and water content of bio-oil could reduce to 61.5%. The bio-oil and char yields were higher when rice straw was pyrolysed, while gas yield was higher when rice husk was used. Metal salts showed great selectivity on compositions of bio-oil. LiCl and FeCl2 promoted biomass to pyrolyse into smaller molecular weight compounds. CrCl3, CaCl2 and LaCl3 could restrain second pyrolysis of bio-oil. The research provided a scientific reference for production of bio-oil from biomass pyrolysis in molten salt.
Biofuels ; analysis ; Bioreactors ; microbiology ; Catalysis ; Chlorides ; chemistry ; Lanthanum ; chemistry ; Lipids ; biosynthesis ; Oryza ; metabolism ; Plant Stems ; metabolism ; Potassium Chloride ; chemistry ; Salts ; chemistry ; Zinc Compounds ; chemistry