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Four asymmetric Zn(II) phthalocyanines (Pc1–Pc4) bearing a carboxylic acid group in the peripheral position have been designed and synthesized to investigate the influence of the distance between COOH group and the phthalocyanine core on their photophysical and photochemical properties. The novel phthalocyanine complexes were characterized by ¹H, ¹³C NMR, IR, and UV-vis spectroscopies, elemental analysis and matrix-assisted laser desorption ionization mass spectrometry (MALDI). The aggregation behavior, photophysical and photochemical properties such as fluorescence lifetime and quantum yields and singlet oxygen quantum yields of Pc1–Pc4 were explored in tetrahydrofuran (THF) to the determination of the potential use of these novel phthalocyanines as photosensitizers for different applications such as photovoltaic technologies and photodynamic therapy (PDT). Pc1–Pc4 exhibited high singlet oxygen generation quantum yields (0.84, 0.66, 0.88 and 0.65, respectively). Fluorescence quantum yields could be obtained for Pc1, Pc2, Pc3 and Pc4 (0.13, 0.31, 0.10 and 0.25, respectively) in THF.

The catalytic functionalization of C–H, C–OH and C–C bonds belongs to the most important processes in nature and the industry. In nature, this process occurs via involvement of enzymes, effectively and selectively, usually with very high turnover numbers. The pivotal role in enzymatic activity is played by the metal center cofactors, which involve several bioavailable transition metals, such as, iron, copper, manganese and zinc. In the industry, bond functionalization requires the presence of metal catalysts; therefore, a bio-inspired design of metal catalysts is a challenging approach. The recent advances in the catalysis of industrially important reactions, namely the oxidation and hydrocarboxylation of alkanes, the oxidation of alcohols and C–C coupling are reported. Convenient, environmentally friendly methods are presented, and the role and efficacy of the various transition-metal (iron, copper, zinc, manganese, nickel, vanadium, palladium and cobalt) catalysts are explored.

The 10,000 or more species of diatoms are microscopic photosynthetic organisms of the class Bacillariophyceae in the phylum Heterokontophyta. They are dominant primary producers in marine and inland water habitats, and may account for up to 20% of global primary productivity. The core carboxylation enzyme in their photosynthesis is Form ID Rubisco (ribulose bisphosphate carboxylase–oxygenase), which, if it replaced rice Form IB Rubisco on a molecule-for-molecule basis, would give slightly lower rates of photosynthesis at extant CO₂ concentrations. These kinetic characteristics, along with the low conductance for CO₂ of aqueous boundary layers, rationalize the occurrence of CCMs (inorganic carbon-concentrating mechanisms) in all diatoms investigated. It was assumed that these mechanisms, which increase the CO₂ concentration around Rubisco, were all based on active transport of CO₂, HCO₃^- or H⁺ across membranes. It now appears, from recent extensions of earlier work, that there is a C₄-like photosynthetic carbon metabolism in certain diatoms. However, more work is needed to determine the extent to which diatoms have photosynthesis analogous to that of single-cell C₄ higher plants. The relevance of this work to producing C₄ rice probably comes more from concepts than from the direct introduction of diatom genes in rice. One such concept is the possibility that C₄-like photosynthesis in diatoms involves no carbonic anhydrases (CAs), and so needs less Zn. However, this requires HCO₃^- entry, so decreased Zn costs of growth may be less readily achieved in rice unless phosphorenolpyruvate carboxykinase (using CO₂) replaces phosphoenolpyruvate carboxylase (using HCO₃^-) as the C₄ carboxylase.

The structure and chemistry of mammalian metallothioneins (MTs) with divalent (Zn^II, Cd^II) and monovalent (Cu^I) metal ions pertinent to their role in biological systems are discussed. In human, four MT isoforms designated MT-1 through MT-4 are found. The characteristic feature of these cysteine- and metal-rich proteins is the presence of two metal-thiolate clusters located in independent protein domains. The structure of these clusters is highly dynamic, allowing a fast metal exchange and metal transfer to modulate the activity and function of zinc-binding proteins. Despite the fact that the protein thiolates are involved in metal binding, they show a high reactivity toward electrophiles and free radicals, leading to cysteine oxidation and/or modification and metal release. The unusual structural properties of MT-3 are responsible for its neuronal growth inhibitory activity, involvement in trafficking of zinc vesicles in the central nervous system (CNS), and protection against copper-mediated toxicity in Alzheimer's disease. MT-1/MT-2 also play a role in cellular resistance against a number of metal-based drugs.

Metallothionein (MT) is an avid metal-binding (metal + thiol/sulphur-binding) protein in the human body. It binds to trace elements like zinc and copper as well as heavy metals like cadmium, and plays an important role in metal detoxi-fication and homeostasis. MT isoforms are expressed differentially in benign and malignant prostate tissue, with increased MT expression noted in higher-Gleason-grade prostate cancer. MT expression in prostate has been shown to be regulated by high Zn concentration and promoter hypermethylation. MT is known to play a role in the resistance to chemotherapeutic agents such as cisplatin and radiation treatment, presumably by trace metal or free radical scavenging. MT expression in the prostate gland is of particular interest because heavy metals such as Zn, which is present at the highest concentration in prostate compared to other human organs, induce MT expression and may be amenable to therapeutic manipulation in order to improve sensitivity to chemotherapy and radiation. MT may prove to be a useful therapeutic target for novel approaches such as local or systemic heavy metal chelation therapy and gene vectors for treating patients with prostate cancer.

Zinc status, inflammation, and genetic determinants are prominent mechanisms in the pathogenesis of atherosclerosis (AT) and its compliances (cardiovascular diseases). In this review, we report the possible impact of zinc on AT development as well as the role played by a significant genetic determinant involved in inflammation, such as interleukin-6 (IL-6). Genetic polymorphism of IL-6 may affect a different inflammatory response as well as zinc turnover, predisposing to AT. Indeed, zinc deficiency is suggested as a risk factor for AT with advancing aging. The increment of dysfunctional proteins involved in zinc homeostasis, i.e. metallothioneins (MT), caused by persistent inflammation and oxidative stress may further contribute to zinc deficiency and consequently to the development of AT. A zinc supplementation may be useful to achieve healthy aging and, as such, to prevent AT, but it is necessary to consider the individual genetic background (especially when referred to IL-6 and MT polymorphisms) for the success of zinc intervention. Therefore, a zinc genomic approach may offer a reasonable hope for understanding the impact of zinc on molecular processes that maintain health and prevent the development of AT.

Metallothioneins (MTs) are cysteine-rich proteins capable of scavenging free radicals and sequestering metal ions. In the liver, these proteins are involved in copper and zinc metabolism, in the chelation of heavy metals, and in protection against oxidative damage. Because of their properties, MTs are involved in many liver diseases, which can be sorted into the following:

1. Metal storage liver diseases. Zinc, which is an important anticopper agent for Wilson's disease, acts by increasing the concentration of MTs in the enterocytes, thereby reducing metal absorption. Copper also accumulates in the liver in cholestatic diseases, in which MTs are reportedly overexpressed and induced by ursodeoxycholic acid (UDCA), the main drug used to treat cholestasis. The role of MTs in hemochromatosis, an iron-accumulating disease, has yet to be established; but in animal models, it has been suggested that zinc, by increasing MT concentration, could exert a beneficial effect.

2. Toxic liver diseases. By sequestering metal ions and scavenging free radicals, MTs protect against damage caused by exogenous toxic substances, such as cadmium and arsenic, and by the toxic effects on hepatocytes of ethanol and at in alcoholic and nonalcoholic liver diseases.

3. Chronic viral hepatitis. By lowering the inflammatory injury, MTs have a protective action against chronic liver damage; a relationship has also been described between MTs and the severity of liver disease and the response to therapy.

4. Hepatocellular carcinoma. MTs are downexpressed and inversely correlated with tumor stage; an inverse correlation has also been reported between MT concentrations and response to platinum chemotherapy.

Given the ability of zinc to strongly induce MT synthesis, zinc supplementation could be useful not only in Wilson's disease, but also in other liver diseases in which MTs exert a protective effect.

The central nervous system (CNS) is partially protected from circulating toxicants by the blood-brain barrier. However, for xenobiotics which are excluded from the CNS the olfactory pathway provides an alternative route of passage into the brain. Thus, in the olfactory epithelium the primary olfactory neurons have dendrites in contact with the nasal lumen and axons which project to the olfactory bulbs. Materials which come into contact with the olfactory epithelium may be taken up in the primary olfactory neurons and transported to the olfactory bulbs and even further into other areas of the brain. The article deals with the uptake and transport of metals in the olfactory system. Metals discussed are mainly manganese, cadmium, nickel, aluminum, zinc, cobalt and mercury. Among these metals manganese has a unique capacity to be taken up via the olfactory pathway. Thus, following transport along the primary olfactory neurons to the olfactory bulbs manganese continues via secondary and tertiary olfactory neurons and further connections to all parts of the brain and even into the spinal cord. Cadmium is transported along the axons of the primary olfactory neurons to the olfactory bulb, but this metal appears unable to leave the terminal arborizations of the axons in the glomeruli of the bulb. Studies with nickel, zinc, cobalt and mercury indicate that these metals are transported along the primary olfactory neurons and accumulated in the olfactory nerve layer and the glomerulular layer of the bulbs. In addition, low levels of these metals leave the terminations of the primary olfactory neurons. There is evidence that mercury also may undergo axonal transport in the primary olfactory neurons following uptake in these neurons from the systemic circulation. This may be a part of a more general ability of mercury to be taken up in neurons with access to the systemic circulation and reach the CNS via transport in these neurons. There is evidence that aluminum is transported along the olfactory pathway, but the fate of this metal in the olfactory system is not yet known in detail. The olfactory pathway is a route by which metals may circumvent the blood-brain barrier and reach the central nervous system. The possibility that uptake and transport of metals in the olfactory pathways may induce olfactory dysfunction and neurotoxicity should be taken into account in risk assessments of occupational metal exposure via inhalation.

Zinc is relevant to the maintenance of brain functions. It is involved in glutaminergic transmission in the gene expression of transcriptional factors and in nerve growth factor activity. Zinc turnover in the brain is mediated by metallothionein (MT) and the zinc traffic into the brain is due to ZnTl-4 transporter proteins. Alterations in zinc turnover lead to brain dysfunction. During aging, zinc turnover is altered, coupled with decreased brain functions and impaired cognitive performances. This decrease may lead to neurodegeneration. One of the causes of altered zinc turnover in aging may be due to altered zinc-bound MT homeostasis, which transforms from being a protective shield against stress into a harmful factor in aging because of the exclusive sequestration of zinc and lack of subsequent zinc release by MT for brain functions. The beneficial effect of zinc supplementation is discussed in aging and neurodegeneration.

Alzheimer's disease is an age-dependent neurodegenerative disorder associated with parenchymal and cerebrovascular deposition of fibrillized amyloid-β protein. Strong genetic evidence implicates the amyloid-β protein and its precursor, the amyloid-β protein precursor in the pathogenesis of Alzheimer's disease. Amyloid-β and amyloid-β protein precursor are both metalloproteins, and significant progress has been made toward understanding their biologic functions. A growing body of evidence links pathophysiologic copper and zinc metabolism to Alzheimer's disease. The role of copper and zinc in Alzheimer's disease, as well as possible physiological and pathophysiological interactions between these metals and amyloid-β and amyloid-β protein precursor, is reviewed here and therapeutic implications are discussed.

The effects of sonication during electrolysis include the cavitation phenomena. The collapse of a bubble near the surface of substrate causes the formation of high-speed liquid jet towards the surface of substrate, which travels along its surface. The liquid jet speed is 120 m/s, the water hammer pressures is 200 MPa and shock wave pressure is 1000 MPa. In this work the crystal orientation and hardness of zinc electrodeposited films were determined by frequency of ultrasonic irradiation, flow rate and hydrostatic pressure. The texture coefficient of {002} plane increased, and {100} and {102} planes decreased with sonication and increasing of acoustic intensity. These effects maximized at 45 kHz and 0.35 W/cm². The texture coefficient of {002} plane increased, and {100} plane decreased with increasing of hydrostatic pressure. The crystal orientations were not affected with liquid flow. The hardness of deposited films increased with increasing of acoustic intensity and maximized at 45 kHz and 0.35 W/cm². The hardness decreased with increasing of hydrostatic pressure. It was concluded that the effects of sonication on the hardness were shock wave pressures.

Inquiries comparatively was carried out on the ability of biosorption of copper and zinc for the biomass of Phanerochaete chrysosporium UCP 963 and Cunninghamella elegans UCP 596. The strain of C. elegans showed ability to removal of heavy metals in the concentration of 4 mM with incomes of 55% of removal of copper, and 51% of zinc, respectively, and in the concentration of 6 mM zinc was removed 53% and copper 57%, all the treatment using 120 mg of the biomass. The inactivated biomass of P. chrysosporium was more efficient in the copper removal in the concentration of 6 mM with results of 45% of removal and in both zinc concentrations (4 and 6 mM) it presented a sorption of 59-63 %, respectively, during 480 minutes. The results demonstrate that inactivated biomass and/or live biomass of P. chrysosporium and C. elegans presents ability of removal of copper and zinc.

Due to continuously higher demands from different organizations and severe legislation on passive automotive safety and the effort to reduce vehicle emissions, the use of high- and ultra-high strength components in both car body and closures have increased drastically during the last two decades. An increased interest has been directed towards the use of press hardened steel in underbody parts. However, the lower part of the body in white (BIW) can be highly affected by corrosion due to the harsh road environment. Consequently enhanced corrosion protection properties is desired. The Zn coated material (GA, GI) for the direct press hardening process show better corrosion properties then the reference materials/coatings used in this investigation and is therefore suited also for under body parts in the BIW. The surface defects (LME and micro cracks) are avoided using the new process and tool technology for forming at low temperature. Even if the forming operation is done at low temperature, the tensile properties fulfil the requirements. The friction coefficient is lower for the GA material in comparison with the AlSi-coated reference and this indicate that the formability is better and that more complex shaped parts can be produced with this material and new process.

Due to continuously higher demands from different organizations and severe legislation on passive automotive safety and the effort to reduce vehicle emissions, the use of high- and ultra-high strength components in both car body and closures have increased drastically during the last two decades. An increased interest has been directed towards the use of press hardened steel (sometimes referred to as hot stamped steel) in underbody parts. However, the lower part of the body in white (BIW) can be highly affected by corrosion due to the harsh road environment. Consequently, enhanced corrosion protection properties are desired. In order to meet the higher demands for corrosion protection of press harden steel, zinc coated material for the direct press hardening process will be more frequently used in future car bodies.

In the present study the corrosion properties of zinc coated material for the direct press hardening process have been investigated and compared to references i.e. Aluminized 22MnB5, bare press-hardened 22MnB5 and standard galvanized steel for cold forming. The results show that zinc coated material has an electrochemical potential significantly below the potential of the base material, the boron steel. Hence, it gives a cathodic corrosion protection of the substrate. However the cathodic protection is influenced by the dwell time (total time in furnace) in the press hardening process. The heating dwell time governs the amount and type of Fe–Zn-intermetallic phases formed. Consequently the cosmetic corrosion behaviour of the zinc coated material is connected to the heating dwell time in the press hardening process. The results show that an optimum corrosion resistance is obtained after short dwell time. This can probably be attributed to a combined effect of the galvanic corrosion protection and the thickness of the layer.

We prepared zinc-containing TCP/HAp ceramics (Zn-TCP/HAp) in the shape of disk, and examined the effect of zinc on the osteogenic differentiation of cultured marrow cells on the surface of Zn TCP/HAp. Fresh marrow cells were obtained from the femora of Fischer rats and cultured in a medium containing 15% fetal bovine serum to reach confluent. After trypsinization, the cells were seeded at 20×10³ cells/16 mm ϕ on Falcon tissue wells with the ceramic disk for subculture. Just before the cell seeding, three different disks (TCP/HAp containing 0, 0.126, or 0.316 wt% Zn) were placed in the wells. After 2 weeks of subculture in the presence of β-glycerophosphate, vitamin C phosphate, and dexamethasone, the cells were stained for alkaline phosphatase (ALP). The ALP positive area on the Zn-TCP/HAp disk was expanded with an increase in Zn content, as covering almost the entire surface of the Zn-TCP/HAp disk of 0.316 Zn wt%. The results indicate that the Zn doped TCP/HAp ceramics stimulate osteoblastic differentiation in cultured marrow stromal cells.

Zinc was doped into β-tricalcium phosphate up to 10 mol %. The zinc-doped tricalcium phosphate (ZnTCP), tricalcium phosphate (TCP) and hydroxyapatite (HAP) powders were mixed with a total metal-per-phosphate ratio fixed at 1.60, followed by being sintered into a dense body at 1100°C for 1 hour to make a ZnTCP and HAP composite ceramic (ZnTCP/HAP). The ZnTCP/HAP released calcium, phosphate and zinc ions for at least 30 days in a physiological saline solution.

No inhibitory effect of ZnTCP/HAP on the proliferation of MC3T3-E1 cells was observed up to a zinc content of 1.26 wt%. A relative cell growth rate increased significantly in a zinc content of the ZnTCP/HAP from 0.6 to 1.26 wt%. The ZnTCP and the ZnTCP/HAP ceramics were implanted in the femora of New Zealand White rabbits for four weeks. Histological and histomorphometrical investigation on the undecalcified sections revealed that the bone formation area per area of medullary cavity increased by 51 % (p=0.509, n=6) around the ZnTCP/HAP implants with a zinc content of 0.316 wt%, compared with the control.

The broad spectrum of microbiocidal activity of silver and zinc ions is known as oligodynamic effect. The aim of this work was to provide a facile and robust approach to finish polymeric surfaces with microbiocidal functions, basing on hyperbranched polymers as carriers for silver or zinc ion release agents. Due to the encapsulation of the metal species a high compatibility with various finishing techniques (coating or bulk incorporation) and a controlled release of metal ions in the end use application can be realized. This ensures a high surface activity at low agent content. Both effects could be demonstrated for different polymer material applications.