Zinc Exchange Research Articles

Zinc homeostasis and redox alterations in obesity.

Impairment of both cellular zinc and redox homeostasis is a feature of several chronic diseases, including obesity. A significant two-way interaction exists between redox metabolism and the relatively redox-inert zinc ion. Redox metabolism critically influences zinc homeostasis and controls its cellular availability for various cellular functions by regulating zinc exchange from/to zinc-binding proteins. Zinc can regulate redox metabolism and exhibits multiple pro-antioxidant properties. On the other hand, even minor disturbances in zinc status and zinc homeostasis affect systemic and cellular redox homeostasis. At the cellular level, zinc homeostasis is regulated by a multi-layered machinery consisting of zinc-binding molecules, zinc sensors, and two selective families of zinc transporters, the Zinc Transporter (ZnT) and Zrt, Irt-like protein (ZIP). In the present review, we summarize the current state of knowledge on the role of the mutual interaction between zinc and redox homeostasis in physiology and pathophysiology, pointing to the role of zinc in the alterations responsible for redox stress in obesity. Since zinc transporters primarily control zinc homeostasis, we describe how changes in the expression and activity of these zinc-regulating proteins are associated with obesity.

Zinc ion exchange assisted synthesis of R-TiO2@C hollow spheres with superior lithium-ion storage performance

Nanostructured anode materials hold the key to advance the performance of the corresponding lithium-ion batteries as advanced electrochemical energy storage devices. Here, we designed a zinc exchange assisted phase change strategy as an acid-free and well-controlled approach to successfully synthesize a kind of rutile phase TiO2 @C (R-TiO2 @C) hollow spheres with well-defined size by using SiO2 spheres as sacrificial templates. The exchanged zinc ions in an alcohol solvothermal reaction were considered as a phase transition medium to promote the formation of a high-quality rutile TiO2 crystal through a high temperature solid-state heat way. By this way, the final morphologies of rutile phase TiO2 nanocrystals were well controlled, and the rutile TiO2 phase transformation temperature was lower than that of conventional one-step high temperature calcination way (without zinc ions exchange). Note that it successfully avoided using acids as mediums to promote the formation of rutile phase TiO2 crystal in the nano process. Meanwhile, the carbon layer formed by a hydrothermal carbonization reaction not only provided self-supporting solid-state in situ reducing medium for Zn2+ to Zn vapor but also produced conductive porous carbon coating porous and robust R-TiO2 spherical shell with nanosized subunits. The reaction process and mechanism of zinc ions induced phase transformation were discussed. Benefiting from the nanoscale morphology-regulation and hollow structure with enhanced ability of ion and electron transfer as well as electrolyte transport, the resultant R-TiO2 @C hollow spheres can significantly promote Li ions storage and deliver a high reversible specific capacity of 115.6 mAh g-1 at 5.0 C over 1600 cycles. A typical electrochemical reaction on Li ions inserted into TiO2 crystal was simply elaborated as well. This work demonstrates its great potential for practical application in lithium-ion batteries.

Single-Micelle and Single-Zinc-Particle Imaging Provides Insights into the Physical Processes Underpinning Organozinc Reactions in Water.

Micelles on the surfaces of individual metallic zinc particles are imaged by fluorescence microscopy with sensitivity up to single micelles. These micelles are made fluorescent to enable imaging, through the incorporation of boron dipyrromethene fluorophores as representative organic molecular "cargo". Highlighting an advantage of this in situ and sensitive fluorescence technique, the same micelles are not visible by ex situ scanning electron microscopy/energy dispersive X-ray spectroscopy analysis. Examination of micellar solutions with zinc reveals an aging process: micelles do not immediately adhere to the zinc surfaces upon mixing but rather build up over time. Furthermore, at longer times, smaller zinc particles become fully encased in micelle "shells". Once adhered, micelles remain in the local regions of the zinc surface for the duration of the imaging experiments (>2 h). Single micelles are imaged in solution, and their molecular contents are characterized. Two-color fluorescence crossover experiments show that micelles adhered to the surface of the zinc exchange molecular contents with micelles in solution, achieving molecular exchange equilibrium in ∼2.5 h. Unique (non-ensemble averaged) exchange kinetics are displayed by micelles at different locations on the zinc surface, consistent with exchange kinetics of single micelles or small local clusters of micelles. The aging of the micellar solutions and the rate of exchange while on the surface of the zinc suggest that micelle mass transport processes may contribute to overall reaction barriers in sustainable organozinc cross-coupling reactions in micellar water. The observed aging of the system suggests routes for improvement of preparative, bench-scale synthetic reactions involving micellar preparations of organozinc compounds.

Zinc Containing Small‐Pore Zeolites for Capture of Low Concentration Carbon Dioxide

AbstractThe capture of low concentration CO2 presents numerous challenges. Here, we report that zinc containing chabazite (CHA) zeolites can realize high capacity, fast adsorption kinetics, and low desorption energy when capturing ca. 400 ppm CO2. Control of the state and location of the zinc ions in the CHA cage is critical to the performance. Zn2+ loaded onto paired anionic sites in the six‐membered rings (6MRs) in the CHA cage are the primary sites to adsorb ca. 0.51 mmol CO2/g‐zeolite with Si/Al=ca. 7, a 17‐fold increase compared to the parent H‐form. The capacity is increased further to ca. 0.67 mmol CO2/g‐zeolite with Si/Al=ca. 2 due to more paired sites for zinc exchange. Zeolites with double six‐membered rings (D6MRs) that orient 6MRs into the cages give enhanced uptakes for CO2 adsorption with zinc exchange. The results reveal that zinc exchanged CHA and several other small pore, cage containing zeolites merit further investigation for the capture of low concentration CO2.

Zinc Containing Small‐Pore Zeolites for Capture of Low Concentration Carbon Dioxide

AbstractThe capture of low concentration CO2 presents numerous challenges. Here, we report that zinc containing chabazite (CHA) zeolites can realize high capacity, fast adsorption kinetics, and low desorption energy when capturing ca. 400 ppm CO2. Control of the state and location of the zinc ions in the CHA cage is critical to the performance. Zn2+ loaded onto paired anionic sites in the six‐membered rings (6MRs) in the CHA cage are the primary sites to adsorb ca. 0.51 mmol CO2/g‐zeolite with Si/Al=ca. 7, a 17‐fold increase compared to the parent H‐form. The capacity is increased further to ca. 0.67 mmol CO2/g‐zeolite with Si/Al=ca. 2 due to more paired sites for zinc exchange. Zeolites with double six‐membered rings (D6MRs) that orient 6MRs into the cages give enhanced uptakes for CO2 adsorption with zinc exchange. The results reveal that zinc exchanged CHA and several other small pore, cage containing zeolites merit further investigation for the capture of low concentration CO2.

Антиковидные продукты из водных биоресурсов

The formation of collective immunity, in the context of the COVID-19 pandemic, is directly related to the state of health of each member of the community, therefore, taking care of the health of citizens becomes one of the priority tasks of any state. Recent studies have shown that vitamin D, essentially being a hormone D, strengthens the innate immunity associated with the exchange of zinc in the human body, which, in turn, affects the replication of viruses and accel-erates their excretion. Omega-3 fatty acids have a wide spectrum of biological activity, includ-ing in the treatment of inflammatory processes of various etiologies.

RESEARCH ON COPPER-67 SEPARATION OBTAINED BY PHOTO-NUCLEAR FROM ZINC OF NATURAL COMPOSITION

In the world, it is planned to produce promising for the manufacture of radiopharmaceuticals of radioisotope copper-67 by the reaction of its production from zinc-68 under the influence of γ-radiation on an electron accelerator. The next major issue is the separation of copper and zinc. Extraction, ion exchange and thermal distillation of zinc have already been studied in detail. Co-precipitation of copper with low zinc and thermal distillation of organic compounds of metals is promising.

Zinc-substituted Ag2CrO4: A material with enhanced photocatalytic and biological activity

Abstract In the past years, new environmentally-friendly photocatalysts have been reported, but the realization of efficient visible-light driven photocatalyst with highly active bactericidal and fungicidal activity is still challenging. This work is a joint experimental and theoretical study on the structural, electronic, and optical properties of Ag2CrO4:Zn2+ (ACOxZn, x = 1%, 2%, and 4%) solid solutions for photocatalytic, bactericidal, and fungicidal activity. For the first time, synthesis of these innovative and multifunctional materials were performed through the cation exchange of zinc and silver using a simple, fast, and cheap co-precipitation method. Powder X-ray diffraction measurements revealed the long range order of the materials. X-ray photoelectron spectroscopy provided information about the surface of the samples demonstrating that they were pure. The materials showed short-range order as verified by FT-Raman spectroscopy. Additionally, ultraviolet-visible diffuse reflectance spectra and photoluminescence spectroscopy were used to examine the electronic properties which corroborated with the increasing photocatalytic activity for the degradation of Rhodamine B and bactericidal activity against Staphylococcus aureus and Candida albicans. Field emission scanning electron microscopy images showed different types of particles with different facets and sizes. Theoretical results based on density functional theory calculations complement the experimental results to rationalize the effects of the incorporation of Zn cations in the ACO host lattice.

Recent Advances of the Halogen-Zinc Exchange Reaction.

For the preparation of zinc organometallics bearing highly sensitive functional groups such as ketones, aldehydes or nitro groups, especially mild halogen–zinc exchange reagents have proven to be of great potential. In this Minireview, the latest research in the area of the halogen–zinc exchange reaction is reported, with a special focus lying on novel dialkylzinc reagents complexed with lithium alkoxides. Additionally, the preparation and application of organofluorine zinc reagents and transition‐metal‐catalyzed halogen–zinc exchange reactions are reviewed.

Exchange of zinc, cobalt and selenium in highly productive cows in the first 100 days of lactation when feeding them mixed ligand complexes

Exchange of zinc, cobalt and selenium in highly productive cows in the first 100 days of lactation when feeding them mixed ligand complexes

FEATURES OF BILIARY TRACT FUNCTION OF THE LIVER WITH MECHANICAL TRAUMA OF VARYING SEVERITY AGAINST THE BACKGROUND OF POISONING WITH SALTS OF COPPER AND ZINC

Skeletal trauma causes significant biliary tract violations of the liver. Excess copper ions and zinc reduces biliary function of the liver.
 The aim of the study – to find out the pathogenetic features of liver damage in the case of mechanical injury of varying severity in the presence of excess copper and zinc ions in the body and its antidote therapy.
 Material and Methods. Experiments were performed on 150 non-linear white male rats weighing 180–200 g. In the context of chronic intoxication with copper and zinc sulfates, they simulated skeletal trauma of varying severity. In animals after 1, 3 and 7 days of post-traumatic period, bile duct function of the liver was studied. The received digital data was subject to statistical analysis.
 Results and Discussion. Against the background of a medium-degree injury, the indicator varied wavy: after 1 day it increased significantly in relation to the control group (by 32.7 %, p<0.05). After 3 days it significantly decreased and became 17.6 % less than control (p<0.05). After 7 days, it continued to remain at the same level (p<0.05 for control). In conditions of excessive ion exchange of copper and zinc in 1 day the indicator was at the control group level (p>0.05). However, after 3 and 7 days it was significantly lower than the reference level (27.8 % and 24.3 % respectively, p<0.05). In these conditions, after 1 and 3 days, the indicator was statistically significantly lower on the background of excessive intake of copper and zinc ions (31.6 % and 12.4 % respectively, p<0.05).
 Conclusions. Skeletal trauma causes a significant violation of biliary tract function of the liver. At a trauma of a light degree without intoxication copper and zinc salts in 1 day the index to 7 days increases. While in the middle and severe injuries, after 1 day it is greater than control, but in the future it is lower than the control group. Excessive intake of copper ions and zinc contributes to a decrease in the studied index from 1 to 7 days, and with the trauma of moderate and severe severity of the lungs 3 and 7 days it becomes significantly lower than in the nontoxic group.

Mixed metals migration through zeolite-amended backfills for vertical cut-off walls

Column tests were performed with two sand–bentonite backfills comprising 5·8% bentonite with 5% of one of two high-cation-exchange-capacity (CEC) zeolite amendments – clinoptilolite and chabazite upper bed (chabazite-UB). The backfill specimens were permeated with a mixed salt solution of 17·5 mM potassium chloride (KCl) and 10 mM zinc chloride (ZnCl2) to evaluate the extent of attenuation of two metals – potassium (K) and zinc (Zn). The specimens were characterised by low hydraulic conductivity (<1·0 × 10−9 m/s) and delayed breakthrough of potassium and zinc that was consistent with exchange of potassium (K+) and zinc (Zn2+) ions for the sodium (Na+) and/or calcium (Ca2+) ions initially occupying the exchange sites of the bentonite and zeolite components of the backfills. The results were consistent with those previously reported for the same backfills permeated with single-salt solutions of the same metals, indicating that the competition between potassium and zinc ions in the mixed salt solution had little effect on the metals migration. Overall, the metals attenuation was enhanced relative to that for the unamended backfill by a factor ranging from 2·0 for zinc with both zeolite-amended backfills to 3·7 for potassium with the chabazite-UB-amended backfill, further illustrating the benefit resulting from amending a sand–bentonite backfill with a small amount of high-CEC zeolite.

Augmentation of Nanofluids Heat transfer in a Circular Tube with Baffled Winged Twisted Swirl Generator

This article introduces a numerical study on heat exchange and corrosion coefficients of Zinc–water nanofluid stream in a circular tube fitted with swirl generator utilizing CFD emulation. Different forms of swirl generator which have the following properties of plain twisted tape (PTT) and baffle wings twisted tape (BTT) embeds with various ratio of twisting (y = 2.93, 3.91 and 4.89), baffle inclination angles (β = 0°, - 30° and 30) joined with 1%, 1.5% and 2% volume fraction of ZnO nanofluid were utilized for simulation. The results demonstrated that the heat and friction coefficients conducted by these two forms of vortex generator raised with Reynolds number, twist ratio and baffle inclination angles decreases. Likewise, the results showed that the heat transfer rate raised with accretion of ZnO nanoparticle concentration. Furthermore, the maximum rate of heat transfer with significant intension in friction coefficient has been produced by baffle wings tape with ratio of twisting y=2.93 and baffle angle β= -30 with 2% volume fraction of ZnO nanofluid.

Structural and Antibacterial Properties of HyZnxNa2−xSi14O29 nH2O Layered Silicate Compounds, Prepared by Ion-Exchange Reaction

In this paper, zinc ion-exchange into the interlayer space of magadiite at different theoretical rates Zn2+/Si14O29 was investigated. Five Zn-exchanged materials, HyZnxNa2−xSi14O29 nH2O (x = 0.06, 0.21, 0.35, 0.57 and 0.82), were prepared and characterized using several techniques. As results, X-ray diffraction reveals that the basal spacing (d001) of the derivatives decreases with the increase of the zinc exchange rate, confirming the intercalation of zinc ions into the layer spaces of magadiite. This result is supported by thermogravimetric analysis, where an increase in decomposition temperatures is observed for Zn-exchanged materials. The introduction of Zn2+ ions into the interlayer space does not substantially affect the structure of the magadiite, but rather tends to stabilize it by increasing the decomposition temperature of the silanol groups. The UV-Visible DR analysis shows the presence of more than one intercalated zinc species in the all Zn-exchanged magadiite materials. The antibacterial activity for all exchanged materials was evaluated by the disc inhibition method against E. Coli and S. Aureus. The results show that the activity is strongly dependent on the zinc content of the Zn-exchanged material.

Diffusion and Defect Phenomena in III-V Semiconductors and their Investigation by Transmission Electron Microscopy

This article reviews the studies of diffusion and defect phenomena induced by high-concentration zinc diffusion in the single-crystal III-V compound semiconductors GaAs, GaP, GaSb and InP by methods of transmission electron microscopy and their consequences for numerical modelling of Zn (and Cd) diffusion concentration profiles. Zinc diffusion from the vapour phase into single-crystal wafers has been chosen as a model case for interstitial-substitutional dopant diffusion in these studies. The characteristics of the formation of diffusion-induced extended defects and of the temporal evolution of the defect microstructure correlate with the experimentally determined Zn profiles whose shapes depend on the chosen diffusion conditions. General phenomena observed for all semiconductors are the formation of dislocation loops, precipitates, voids, and dislocations and of Zn-rich precipitates in the diffusion regions. The formation of extended defects near the diffusion front can be explained as result of point defect supersaturations generated by interstitial-substitutional zinc exchange via the kick-out mechanism. The defects may act as sinks for dopants and as sources and sinks for point defects during the continuing diffusion process, thereby providing a path to establishing defect-mediated local point defect equilibria. The investigations established a consistent picture of the formation and temporal evolution of defects and the mechanisms of zinc diffusion in these semiconductors for diffusion conditions leading to high-concentration Zn concentrations. Based on these results, numerical modelling of anomalously shaped dopant concentration profiles leads to satisfactory quantitative results and yields information on type and charge states of the point defect species involved, also for near-surface Zn concentration profiles and the absence of extended defects.

Effect of Cu and Zn ion-exchange locations on mordenite performance in dimethyl ether carbonylation

Cu2+ and Zn2+ ion-exchange locations in mordenite (MOR) were evaluated using infrared spectroscopy, pore-size distribution, and temperature-programmed reduction. Isolated copper ions were the most abundant ion-exchanged species, as detected by UV-vis spectroscopy, in addition to oxide nanoparticles, with no presence of binuclear species, which was assigned to a low copper loading of 0.3 Cu/Al. The characterization revealed that only zinc could exchange in 8-membered rings. Hartree-Fock modeling confirmed copper exchange into 12-membered rings involving at least one T1 atom, and zinc exchange in T4 sites and in 8-membered structures, including T3 sites. Copper ion exchange did not offer improvement in the dimethyl ether carbonylation rate or selectivity over acidic mordenite. Zinc ion exchange led to the selectivity and stability improvement with some loss of activity. This work contributes to the understanding of acid and metal site contribution to DME carbonylation and contributes to the understanding for Cu2+ and Zn2+ ion-exchange locations in MOR with a low metal/Al loading (<0.2).

A concise and practical stereoselective synthesis of ipragliflozin L-proline.

A concise and practical stereoselective synthesis of ipragliflozin L-proline was presented starting from 2-[(5-iodo-2-fluorophenyl)methyl]-1-benzothiophene and 2,3,4,6-tetra-O-pivaloyl-α-D-glucopyranosyl bromide without catalyst via iodine–lithium–zinc exchange. The overall yield was 52% in three steps and the product purity was excellent. Two key diastereomers were prepared with efficient and direct access to the α-C-arylglucoside.

ChemInform Abstract: A One‐Pot Dilithiation—Lithium—Zinc Exchange—Negishi Coupling Approach to 2,6‐Di(hetero)aryl Substituted Dithienothiazines — A Novel Class of Electronically Fine‐Tunable Redox Systems.

ChemInform Abstract: A One‐Pot Dilithiation—Lithium—Zinc Exchange—Negishi Coupling Approach to 2,6‐Di(hetero)aryl Substituted Dithienothiazines — A Novel Class of Electronically Fine‐Tunable Redox Systems.

ChemInform Abstract: Dialkylzinc‐Mediated Cross‐Coupling Reactions of Perfluoroalkyl and Perfluoroaryl Halides with Aryl Halides.

AbstractA chemoselective perfluoroalkylation becomes possible by halogen—zinc exchange followed by coupling with a broad spectrum of aryl iodides and some bromides.

Dialkylzinc-mediated allylic polyfluoroarylation reaction

We present an allylic polyfluoroarylation reaction with broad substrate scope and excellent functional group tolerance, using organozinc reagents under mild conditions. A catalytic amount of triphenylphosphine oxide efficiently promotes iodine–zinc exchange reaction between polyfluoroaryl iodide and dimethylzinc, and the resulting phosphine oxide-activated polyfluoroarylzinc undergoes substitution reaction with allylic halides to afford the corresponding polyfluoroarylated products.