Size and Strain of Zinc Sulfide Nanoparticles Altered by Interaction with Organic Molecules.

Nanosized zinc sulfides (nano-ZnS) have size-dependent and tunable physical and chemical properties that make them useful for a variety of technological applications. For example, structural changes, especially caused by strain, are pronounced in nano-ZnS < 5 nm in size, the size range typical of incidental nano-ZnS that form in the environment. Previous research has shown how natural organic matter impacts the physical properties of nano-ZnS but was mostly focused on their aggregation state. However, the specific organic molecules and the type of functional groups that are most important for controlling the nano-ZnS size and strain remain unclear. This study examined the size-dependent strain of nano-ZnS synthesized in the presence of serine, cysteine, glutathione, histidine, and acetate. Synchrotron total scattering pair distribution function analysis was used to determine the average crystallite size and strain. Among the different organic molecules tested, those containing a thiol group were shown to affect the particle size and size-induced strain most strongly when added during synthesis but significantly reduced the particle strain when added to as-formed nano-ZnS. The same effects are useful to understand the properties and behavior of natural nano-ZnS formed as products of microbial activity, for example, in reducing environments, or of incidental nano-ZnS formed in organic wastes.

Assessment of the In Vivo Release and Biocompatibility of Novel Vesicles Containing Zinc in Rats.

This paper is focused on the in vivo release and biocompatibility evaluation in rats of some novel systems entrapping zinc chloride in lipid vesicles. The particles were prepared by zinc chloride immobilization inside lipid vesicles made using phosphatidylcholine, stabilized with 0.5% chitosan solution, and dialyzed for 10 h to achieve a neutral pH. The submicrometric systems were physico-chemically characterized. White Wistar rats, assigned into four groups of six animals each, were treated orally with a single dose, as follows: Group I (control): deionized water 0.3 mL/100 g body weight; Group II (Zn): 2 mg/kg body weight (kbw) zinc chloride; Group III (LV-Zn): 2 mg/kbw zinc chloride in vesicles; Group IV (LVC-Zn): 2 mg/kbw zinc chloride in vesicles stabilized with chitosan. Haematological, biochemical, and immune parameters were assessed after 24 h and 7 days, and then liver fragments were collected for histopathological examination. The use of zinc submicrometric particles-especially those stabilized with chitosan-showed a delayed zinc release in rats. No substantial changes to blood parameters, plasma biochemical tests, serum complement activity, or peripheral neutrophils phagocytic capacity were noted; moreover, the tested substances did not induce liver architectural disturbances. The obtained systems provided a delayed release of zinc, and showed good biocompatibility in rats.

In vitro and In vivo toxicity analysis of zinc selenium/zinc sulfide (ZnSe/ZnS) quantum dots.

Despite the versatility of quantum dots (QDs) in optoelectronics and biomedical field, their toxicity risks remain a considerable hindrance for clinical applications. Cytotoxicity of Cadmium containing QDs is well documented and reveals that they are toxic to cells. Reports suggest that the presence of toxic elements at the QD core (e.g., cadmium, selenium) is responsible for its toxicity in in vivo and in vitro levels. Hence, here the toxicity of heavy metal free ZnSe/ZnS QDs on two scenarios were assessed, (i) HEK cells as in vitro system and (ii) Swiss Albino mice as in vivo model. Before toxicity analysis, QDs subjected to various optical and physico-chemical characterization methods such as absorption and emission spectra analysis, observation under U.V light, TEM, DLS, Zeta potential, FTIR, Raman and XPS spectra, ICP-OES, TGA and DTG curve. It is very necessary to characterize the synthesized QDs because their toxicity greatly influenced by the physico-chemical properties. On checking the vulnerability of HEK cells on exposure to ZnSe/ZnS QDs, the obtained results disclose that ZnSe/ZnS QDs showed merest impact on cellular viability at a concentration less than 100 µg/ml. Acute toxicity of 10 mg/kg ZnSe/ZnS QDs was studied in mice and no clinical or behavioural changes were observed. It did not induce any changes in haematological parameters and any loss of body or organ weight. Moderate pathological changes were evident only in the liver, all others organs like kidney, spleen and brain did not show any manifestations of toxicity. Current work lays substantial bedrock for safe biomedical and environmental application of ZnSe/ZnS QDs in near future.

Speciation Analysis of Ag2S and ZnS Nanoparticles at the ng/L Level in Environmental Waters by Cloud Point Extraction Coupled with LC-ICPMS.

Toxicity and transport of metal-based nanoparticles (M-NPs) in environmental waters strongly depend on their speciation. A detailed understanding of the composition and speciation of M-NPs is necessary in order to move this field forward. Unfortunately, there is a shortage of analytical methods for metal-sulfide nanoparticles (MS-NPs) in the environment. In this work, a cloud point extraction (CPE) method combined with liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (LC-ICPMS) is developed for sensitive determination of Ag2S- and ZnS-NPs. Under the condition of 0.15% (w/v) of Triton X-114 (TX-114), pH 5, 20 mM NaNO3, incubation temperature of 45 °C, and time of 15 min, MS-NPs and non-MS-NPs were extracted into the surfactant-rich phase. With the sequent addition of 10 mM bis(p-sulfonatophenyl)phenylphosphane dehydrate dipotassium (BSPP) aqueous solution (100 µL) into the CPE-obtained extract, the non-MS-NPs were selectively dissociated into their ionic counterparts while maintaining the original size and shape of Ag2S- and ZnS-NPs. Interestingly, the micelle-mediated behavior suddenly disappeared with the addition of BSPP. Thus, the extract can be injected to LC-ICPMS for speciation analysis of trace Ag2S- and ZnS-NPs. This method exhibited excellent reproducibility (relative standard deviations < 4.9%), high sensitivity with the respective detection limits of 8 ng/L for Ag2S-NPs and 15 ng/L for ZnS-NPs, enabling recoveries of 81.3-96.6% for Ag2S-NPs and 83.9-93.5% for ZnS-NPs when they were spiked into three environmental water samples. Due to its potential applicability to low concentrations of Ag2S- and ZnS-NPs, this method is particularly convenient for monitoring the transformations of AgNPs and ZnO-NPs in the environment.

Phosphine detection in veterinary samples using headspace gas chromatography/tandem mass spectrometry with multiple reaction monitoring.

RATIONALE: Determination of phosphine exposure from zinc or aluminum phosphide fumigants continues to be a routine analytical requirement in veterinary forensic toxicology. There is a need for a more reliable and specific method than simple gas chromatography/mass spectrometry (GC/MS) analysis of sample solvent extracts, as GC/MS of extracts on capillary columns used for general screens involves significant interference from air peaks. METHODS: GC/MS/MS headspace analysis of acid-generated phosphine gas enabled study of the feasibility of devising multiple reaction monitoring (MRM) approaches to the determination of phosphine with greater specificity. RESULTS: Collision-induced dissociation in GC/MS/MS showed that phosphine generated m/z 34 → 31, 32 and 33 ion transitions by sequential proton release as well as minor transitions m/z 34 → 47, 34 → 63 and 63 → 31.5 by intermolecular collisions and double charging. Study of the formation of these product ions enabled development of MRM settings for a highly useful headspace method for phosphine detection. CONCLUSIONS: The method was validated over a working range of 5-100 ppm of phosphide generating phosphine gas which enabled retention of regular screen capillary columns without necessitating separation from air components. The method should have adequate sensitivity and reliability for veterinary toxicology laboratories confronting specimens from animals poisoned by crop fumigants.

Capabilities of asymmetrical flow field - Flow fractionation on-line coupled to different detectors for characterization of water-stabilized quantum dots bioconjugated to biomolecules.

The asymmetric flow field-flow fractionation (AF4) coupled on-line with elemental (inductively coupled plasma-mass spectrometry, ICP-MS) and molecular (fluorescence and UV) detection has been investigated as a powerful tool for the characterization of bioinorganic nano-conjugates. In this study, we described methods for the characterization of biotin-antibody complexes bioconjugated with streptavidin quantum dots (QDs-SA-b-Ab). Operating parameters of AF4 separation technique were optimized and two procedures are proposed using a channel thickness of 350 µm and 500 µm. The use of a 500 µm spacer allowed to achieve an efficient AF4 separation of the QDs-SA-b-Ab complexes from the excess of individual species used in the bioconjugation that was required for a proper characterization of the bioconjugates. Optimization of the AF4 allowed a separation resolution good enough to isolate the QDs-SA-b-Ab bioconjugates from the free excess of b-Ab and QD-SA. The efficiency of the bioconjugation process could be then calculated, obtaining a value of 86% for a 1 QDs-SA: 5 b-Ab bioconjugation ratio. In addition, sample recovery around 90% was achieved.

Triple-Labeling of Polymer-Coated Quantum Dots and Adsorbed Proteins for Tracing their Fate in Cell Cultures.

Colloidal CdSe/ZnS quantum dots were water solubilized by overcoating with an amphiphilic polymer. Human serum albumin (HSA) as a model protein was either adsorbed or chemically linked to the surface of the polymer-coated quantum dots. As the quantum dots are intrinsically fluorescent, and as the polymer coating and the HSA were fluorescent labeled, the final nanoparticle had three differently fluorescent components: the quantum dot core, the polymer shell, and the human serum albumin corona. Cells were incubated with these hybrid nanoparticles, and after removal of non-internalized nanoparticles, exocytosis of the three components of the nanoparticles was observed individually by flow cytometry and confocal microscopy. The data indicate that HSA is partly transported with the underlying polymer-coated quantum dots into cells. Upon desorption of proteins, those initially adsorbed to the quantum dots remain longer inside cells compared to free proteins. Part of the polymer shell is released from the quantum dots by enzymatic degradation, which is on a slower time scale than protein desorption. Data are quantitatively analyzed, and experimental pitfalls, such as the impact of cell proliferation and fluorescence quenching, are discussed.

Quantitative Assessment of Individual Populations Present in Nanoparticle-Antibody Conjugate Mixtures Using AF4-ICP-MS/MS.

A current remaining challenge in nanotechnology is the fast and reliable determination of the ratios between engineered nanoparticles and the species attached to their surface after chemical functionalization. The approach proposed herein based on the online coupling of asymmetric flow field-flow fractionation (AF4) with inductively coupled plasma-tandem mass spectrometry (ICP-MS/MS) allows for the first time the direct determination of such ratios in CdSe/ZnS core-shell quantum dot:rat monoclonal IgG2a antibody (QD:Ab) conjugate mixtures in a single run without any previous sample preparation (i.e., derivatization). AF4 provides full recovery and adequate resolution of the resulting bioconjugate from the excess of nanoparticles and proteins used in the different bioconjugation mixtures (1:1, 2:1, and 3:1 QD:Ab molar ratios were assessed). The point-by-point determination by ICP-MS/MS of the metal to sulfur ratios along the bioconjugate fractographic peak allowed disclosing the mixture of the different species in the bioconjugated sample, providing not only the limits of the range of QD:Ab ratios in the different bioconjugate species resulting after functionalization but also a good estimation of their individual relative abundance in the mixture. Interestingly, a wide variety of compositions were observed for the different bioconjugate mixtures studied (QD:Ab molar ratios ranging from 0.27 to 4.6). The resulting weighted QD:Ab ratio computed in this way for each bioconjugate peak matches well with both the global (average) QD:Ab ratio experimentally obtained by the simpler peak area ratio computation and the theoretical QD:Ab molar ratios assayed, which internally validates the procedure developed.

A cross-sectional study of urinary cadmium concentrations in relation to dietary intakes in Uruguayan school children.

BACKGROUND: Cadmium (Cd) exposure has adverse health effects in children. Diet contributes to Cd exposure, but dietary components could affect body Cd levels. OBJECTIVE: To examine associations between diet and urinary Cd (U-Cd) in children. METHODS: In this cross-sectional study conducted in Montevideo, Uruguay, Cd exposure of 5-8 year old children (n = 279 with complete data) was assessed in first morning urine (U-Cd), a marker of long-term exposure, measured by ICP-MS and adjusted for specific gravity. Distribution of U-Cd was (median [5%, 95%]: 0.06 [0.02, 0.17] µg/L); data were natural-log-transformed (ln) for statistical analyses. Serum ferritin (SF), an indicator of iron stores, was measured in fasting samples. Trained nutritionists completed two non-consecutive 24-h dietary recalls with both child and caregiver present. Measures of iron, zinc, calcium and fiber intake, and the consumption of grains, root vegetables, milk, and foods rich in heme iron (white and read meats) and non-heme iron (legumes, spinach, broccoli, tomatoes, dried fruit) were derived. Multivariable ordinary least squares (OLS) and ordinal regressions were used to examine associations among tertiles of water Cd, SF, diet, and U-Cd. OLS models were further stratified by sex. RESULTS: In covariate-adjusted models, SF was not related to ln-U-Cd. Children in highest tertile of iron and zinc intake had lower ln-U-Cd: (-0.23 [-0.42, -0.03]) and (-0.25 [-0.44, -0.05]), respectively, compared to the reference group. Children consuming higher amounts of foods rich in heme iron had slightly lower ln-U-Cd (-0.17 [-0.36, 0.03]). High grain consumption was related to higher ln-U-Cd (0.25 [0.06, 0.45]). CONCLUSIONS: Diets rich in grains were related to higher urinary Cd levels among children living in the context of low Cd pollution. Higher intake of iron and zinc was related to lower Cd levels. Given that urinary Cd is mainly a marker of long-term exposure, these findings should be further corroborated.

Zinc incorporation in marine bivalve shells grown in mine-polluted seabed sediments: a case study in the Malfidano mining area (SW Sardinia, Italy).

Zinc incorporation into marine bivalve shells belonging to different genera (Donax, Glycymeris, Lentidium, and Chamelea) grown in mine-polluted seabed sediments (Zn up to 1% w/w) was investigated using x-ray diffraction (XRD), chemical analysis, soft x-ray microscopy combined with low-energy x-ray fluorescence (XRF) mapping, x-ray absorption spectroscopy (XAS), and transmission electron microscopy (TEM). These bivalves grew their shells, producing aragonite as the main biomineral and they were able to incorporate up to 2.0-80 mg/kg of Zn, 5.4-60 mg/kg of Fe and 0.5-4.5 mg/kg of Mn. X-ray absorption near edge structure (XANES) analysis revealed that for all the investigated genera, Zn occurred as independent Zn mineral phases, i.e., it was not incorporated or adsorbed into the aragonitic lattice. Overall, our results indicated that Zn coordination environment depends on the amount of incorporated Zn. Zn phosphate was the most abundant species in Donax and Lentidium genera, whereas, Chamelea shells, characterized by the highest Zn concentrations, showed the prevalence of Zn-cysteine species (up to 56% of total speciation). Other Zn coordination species found in the investigated samples were Zn hydrate carbonate (hydrozincite) and Zn phosphate. On the basis of the coordination environments, it was deduced that bivalves have developed different biogeochemical mechanisms to regulate Zn content and its chemical speciation and that cysteine plays an important role as an active part of detoxification mechanism. This work represents a step forward for understanding bivalve biomineralization and its significance for environmental monitoring and paleoreconstruction.

Characterization of Cr (VI) - Containing solid phase particles in dry dust deposition in Daejeon, South Korea.

Solid phase speciation of chromium in dry dust deposition and road paint was determined using transmission electron microscopy (TEM) and X-ray absorption spectroscopy (XAS). Spherical black carbon aggregates in dry dust deposition contained discrete nano-sized lead chromate (PbCrO4) and zinc chromate (ZnCrO4), which likely originated from yellow traffic paint and zinc chromate primer (corrosion resistant pigment), respectively based on their main applications. Road marking paint samples from auto roads included lead chromate particles whose size, shape, composition and crystal structure were similar to those in dry dust deposition. A slight difference was found at the particle boundary. Namely, lead chromate in traffic paint was encapsulated by silica-bearing matrix, while discrete lead chromate in the black carbon of dry deposition was rarely enclosed within silica-bearing matrix. The Cr K edge X-ray absorption near edge structure (XANES) spectrum for dry deposition showed the characteristic pre-edge resonance peak similar to the spectra for the Cr(VI) standard and road paint, but the lower intensity. The amount of Cr(VI) accounted for approximately 45% of the total Cr in the dust sample. The solid phase speciation of Cr observed using TEM and their valence states determined using XANES were consistent with the chemical speciation determined using the sequential extraction. The contribution of this study is that XANES was applied to identify Cr valance states in urban dust deposition and zinc chromate was found as a Cr(VI) phase in dry dust deposition using TEM. These study results provide novel data on Cr speciation and Cr(VI)-containing mineral phases in dry dust deposition and their potential sources. Based on the wide use of lead and zinc chromate, atmospheric contamination with these solid phase speciation of Cr(VI) is expected in other cities in the world.

Zinc preconditioning protects against renal ischaemia reperfusion injury in a preclinical sheep large animal model.

Ischaemia-reperfusion injury (IRI) during various surgical procedures, including partial nephrectomy for kidney cancer or renal transplantation, is a major cause of acute kidney injury and chronic kidney disease. Currently there are no drugs or methods for protecting human organs, including the kidneys, against the peril of IRI. The aim of this study was therefore to investigate the reno-protective effect of Zn2+ preconditioning in a clinically relevant large animal sheep model of IRI. Further the reno-protective effectiveness of Zn2+ preconditioning was tested on normal human kidney cell lines HK-2 and HEK293. Anaesthetised sheep were subjected to uninephrectomy and 60 min of renal ischaemia followed by reperfusion. Sheep were preconditioned with intravenous injection of zinc chloride prior to occlusion. Serum creatinine and urea were measured before ischaemia and for 7 days after reperfusion. HK-2 and HEK293 cells were subjected to in vitro IRI using the oxygen- and glucose-deprivation model. Zn2+ preconditioning reduced ischaemic burden determined by creatinine and urea rise over time by ~ 70% in sheep. Zn2+ preconditioning also increased the survival of normal human kidney cells subjected to cellular stress such as hypoxia, hydrogen peroxide injury, and serum starvation. Overall, our protocol incorporating specific Zn2+ dosage, number of dosages (two), time of injection (24 and 4 h prior), mode of Zn2+ delivery (IV) and testing of efficacy in a rat model, a large preclinical sheep model of IRI and cells of human origin has laid the foundation for assessment of the benefit of Zn2+ preconditioning for human applications.

Spray-chilling encapsulation of 2-acetyl-1-pyrroline zinc chloride complex using hydrophobic materials: Feasibility and characterization of microcapsules.

A moisture-sensitive 2-acetyl-1-pyrroline zinc chloride complex (2AP-ZnCl2) was successfully encapsulated by spray-chilling, using a hydrophobic moisture barrier as a practical way to protect the complex and to help facilitate its general use in food applications. Use of octacosane as wall material provided a flavor retention of 65.3%. The results from scanning electron microscopy (SEM) and X-ray micro-computed tomography (X-ray micro-CT) indicated desirable morphological characteristics of the matrix type microcapsules. Gas chromatography (GC) and absorbance spectroscopy were used for chemical quantitation of 2AP and ZnCl2, respectively, in the microcapsules. Results revealed no degradation of 2AP occurred as a result of the encapsulation process. This study is the first to demonstrate the feasibility of producing high quality microcapsules from labile flavor complexes by spray-chilling. The use of generally recognized as safe (GRAS) substances, including 2AP and ZnCl2, may allow for widespread commercial use of 2AP as a flavor ingredient.

Retention of CdS/ZnS Quantum Dots (QDs) on the Root Epidermis of Woody Plant and Its Implications by Benzo[a]pyrene: Evidence from the in Situ Synchronous Nanosecond Time-Resolved Fluorescence Spectra Method.

The retention of CdS/ZnS QDs on the epidermis has been confirmed to be one of the core procedures during the root uptake process. However, the retention mechanisms of QDs on the epidermis of woody plant were poorly understood for lacking of an appropriate QD quantitative method. In this study, a novel method for in situ determination of CdS/ZnS QDs retained on the root epidermis was established using synchronous nanosecond time-resolved fluorescence spectroscopy. No correlations between Kf values of oleylamine-CdS/ZnS QDs retained on the epidermal tissues and the surface/bulk composition of mangrove root were observed (p > 0.05) due to the existence of endocytosis mechanisms during the QD uptake processes. Moreover, the difference of the CdS/ZnS QDs in water and further translocated to xylem/phloem of root rather than the combination with cell wall/membranes was the predominant reason that caused the Kf values to follow the sequence of PEG-COOH-CdS/ZnS QDs < PEG-NH2-CdS/ZnS QDs ≪ oleylamine-CdS/ZnS QDs.

New toothpaste to deal with dentine hypersensitivity: double-blind randomized controlled clinical trial.

OBJECTIVES: The purpose was to evaluate a combined effect of active ingredients contained in new toothpaste in reducing dentine hypersensitivity. METHODS: The tested toothpaste contained active ingredients potassium nitrate (5.00%) and zinc citrate (0.50%). Pain to water stimulus and blowing air was reported on hypersensitive teeth and measured using the VAS (Visual Analogue Scale). The degree of pain to water stimulus was detected after each subject drank a few sips of water which was boiled to the room temperature. Data were collected on each subject's dental history. RESULTS: A significant reduction in dentine hypersensitivity (26-29% after 2 weeks versus 40% after 4 weeks) was detected in the tested group. The controls also showed significant reduction to both stimuli, but at lower rate. A statistically significant difference to blowing air and water stimuli showed the highest impact for the tested group after 4 weeks (P = 0.033, P = 0.006). CONCLUSION: This study supports the efficacy of the tested toothpaste in reducing the phenomenon of dentine hypersensitivity after 4 weeks of usage.

Avaliação do status de zinco considerando diferentes combinações de componentes na síndrome metabólica / Zinc status assessment considering different combinations of components in metabolic syndrome

Introdução: Fatores cardiometabólicos característicos da síndrome metabólica (SM) influenciam no metabolismo do zinco, de forma isolada ou conjuntamente. Objetivo: Comparar as concentrações de zinco no plasma e na dieta entre os três de grupos de indivíduos com SM, distribuídos conforme número de componentes da SM. Métodos: Estudo transversal incluindo 88 indivíduos com SM, diagnosticados segundo NCEP-ATP III. Definiu-se os grupos, considerando três (n=36), quatro (n=40) e cinco componentes da SM (n=12). O zinco da dieta foi avaliado por dois recordatórios de 24h. Verificou-se a pressão arterial, perímetro da cintura e glicemia de jejum, colesterol da lipoproteína de alta densidade e triglicerídeos. O zinco no plasma foi avaliado por espectrofotometria de absorção atômica. As comparações entre os grupos foram realizadas por meio do teste ANOVA, seguido do teste Tukey. Resultados e discussão: A idade média foi de 50(11) anos, predominando o sexo feminino (72%). Observou-se no grupo com três componentes, dez diferentes fenótipos, destacando- se a combinação: hipertensão arterial ou pressão arterial elevada, diabetes mellitus ou glicemia de jejum elevada e perímetro da cintura aumentado (11,4%). Não foram verificadas diferenças significativas do zinco no plasma entre os grupos com três, quatro e cinco componentes, apresentando médias de 92,62(18,26) μg/dL; 86,24(17,88) μg/dL; 86,94(17,12) μg/dL, respectivamente (p>0,05). Constataramse percentuais de inadequação de ingestão de zinco de 75%, 73,6% e 66,6% nos grupos com três, quatro e cinco componentes, respectivamente. Conclusão: Indivíduos com SM, independentemente do número de componentes, apresentam médias de zinco no plasma dentro da normalidade e baixa ingestão de zinco na dieta

Introduction: Cardiometabolic risk factors characteristic of the metabolic syndrome (MS) influence zinc metabolism, either alone or in combination. Objective: This study aims to compare plasma zinc and zinc intake among the three groups of individuals with MS, distributed according to the number of components of SM. Methods: Cross-sectional study including 88 individuals with MS, diagnosed according to NCEP-ATP III. The groups were defined, considering three (n = 36), four (n = 40) and five components of MS (n = 12). Zinc intake was evaluated by two 24-hour recall. Blood pressure, waist circumference and fasting glycemia, high density lipoprotein cholesterol and triglycerides were measured. Analysis of plasma zinc was performed by atomic absorption spectrophotometry. We used ANOVA, followed by the Tukey test, for comparisons between the groups. Results and discussion: The mean age was 5011 years, predominantly female (72%). We found ten different phenotypes based on the three components of MS, with emphasis on the phenotype: arterial hypertension or high blood pressure, diabetes mellitus or fasting blood glucose and increased waist circumference (11.4%). There were no significant differences in plasma zinc between the groups with three, four and five components, presenting a mean of 92.62 (18.26) μg / dL; 86.24 (17.88) μg / dL; 86.94 (17.12) μg / dL, respectively (p> 0.05). The percentages of zinc intake inadequacy were 75%, 73.6% and 66.6% in the groups with three, four and five components, respectively. Conclusion: Individuals with MS, regardless of the number of components, present mean plasma zinc within normal range and low dietary zinc intake

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A highly sensitive fluorescent turn-on biosensor for glycoproteins based on boronic acid functional polymer capped Mn-doped ZnS quantum dots.

A simple fluorescence turn-on sensor has been designed for the highly sensitive detection of glycoproteins on the basis of boronic acid functional polymer capped Mn-doped ZnS quantum dots (QDs@MPS@AAPBA). In the absence of glycoproteins, the fluorescence emission intensity of the QDs@MPS@AAPBA was relatively weaker due to the effective electronic transfer from the QDs to the boron moieties on its surface. While the glycoproteins were introduced into the system, an obvious fluorescence enhancement was observed. It was attributed to the boron moieties covalent binding glycans of the glycoproteins resulting in the electronic transfer process being inhibited. Under the optimal conditions, this fluorescent probe not only could be applied in a wide pH range of 5.0-9.0, but also the binding constants and detection limits of the QDs@MPS@AAPBA for horseradish peroxidase (HRP) and transferrin (TRF) were up to 7.23 × 106 M-1, 1.53 × 107 M-1 and 1.44 × 10-10 M, 3.36 × 10-10 M, respectively. Finally, this proposed method has also been utilized for the TRF determination in serum without any complicated pretreatment and the recovery was in the range of 95.7%-103.0%. As a result, it is promising for application on the glycoproteins detection in complex biological samples.

[Health hazards resulting from exposure to zinc and its inorganic compounds in industry]. / Zagrozenia zdrowotne wynikajace z narazenia na cynk i jego zwiazki nieorganiczne w przemysle.

This article deals with health risks resulting from exposure to zinc and its inorganic compounds in industry. The main source of zinc exposure are fumes generated during thermal and chemical processes, mainly zinc oxide fume formed by immediate oxidation of metallic zinc vapor formed during high-temperature processes, as well as dust generated during the mechanical processing of zinc-containing materials. It is recognized that zinc ions are responsible for health effects of exposure to dust/fumes of the majority of zinc compounds, and the final effect of exposure depends on the degree of dispersion of dusts/fumes suspended in the air. Since the effects of exposure depends on the particle size, occupational exposure limits have began to be established separately for respirable and inhalable fractions. A critical effect of acute exposure to respirable fraction is a "fume fever" which in chronic exposure occurs as an effect associated with recurrent symptoms of acute poisoning. Impaired lung function and asthma symptoms are considered to be the main effects of exposure to inhalable fraction. Due to the limited number of the available data it is not possible to assess carcinogenicity, reproductive toxicity and teratogenicity of zinc and its compounds. The aim of the study was to analyze the major health hazards resulting from occupational exposure to zinc and its inorganic compounds in the context of their physico-chemical properties, a wide range of applications and occupational exposure data. Med Pr 2017;68(6):779-794.

The role of intracellular trafficking of CdSe/ZnS QDs on their consequent toxicity profile.

BACKGROUND: Nanoparticle interactions with cellular membranes and the kinetics of their transport and localization are important determinants of their functionality and their biological consequences. Understanding these phenomena is fundamental for the translation of such NPs from in vitro to in vivo systems for bioimaging and medical applications. Two CdSe/ZnS quantum dots (QD) with differing surface functionality (NH2 or COOH moieties) were used here for investigating the intracellular uptake and transport kinetics of these QDs. RESULTS: In water, the COOH- and NH2-QDs were negatively and positively charged, respectively, while in serum-containing medium the NH2-QDs were agglomerated, whereas the COOH-QDs remained dispersed. Though intracellular levels of NH2- and COOH-QDs were very similar after 24 h exposure, COOH-QDs appeared to be continuously internalised and transported by endosomes and lysosomes, while NH2-QDs mainly remained in the lysosomes. The results of (intra)cellular QD trafficking were correlated to their toxicity profiles investigating levels of reactive oxygen species (ROS), mitochondrial ROS, autophagy, changes to cellular morphology and alterations in genes involved in cellular stress, toxicity and cytoskeletal integrity. The continuous flux of COOH-QDs perhaps explains their higher toxicity compared to the NH2-QDs, mainly resulting in mitochondrial ROS and cytoskeletal remodelling which are phenomena that occur early during cellular exposure. CONCLUSIONS: Together, these data reveal that although cellular QD levels were similar after 24 h, differences in the nature and extent of their cellular trafficking resulted in differences in consequent gene alterations and toxicological effects.

Rhodium(I)-Complexes Catalyzed 1,4-Conjugate Addition of Arylzinc Chlorides to N-Boc-4-pyridone.

Rhodium(I)-complexes catalyzed the 1,4-conjugate addition of arylzinc chlorides to N-Boc-4-pyridone in the presence of chlorotrimethylsilane (TMSCl). A combination of [RhCl(C2H4)2]2 and BINAP was determined to be the most effective catalyst to promote the 1,4-conjugate addition reactions of arylzinc chlorides to N-Boc-4-pyridone. A broad scope of arylzinc reagents with both electron-withdrawing and electron-donating substituents on the aromatic ring successfully underwent 1,4-conjugate addition to N-Boc-4-pyridone to afford versatile 1,4-adducts 2-substituted-2,3-dihydropyridones in good to excellent yields (up to 91%) and excellent ee (up to 96%) when (S)-BINAP was used as chiral ligand.