scholarly journals Phosphate Buffer Solubility and Oxidative Potential of Single Metals or Multielement Particles of Welding Fumes

Atmosphere ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 30
Author(s):  
Manuella Ghanem ◽  
Esperanza Perdrix ◽  
Laurent Yves Alleman ◽  
Davy Rousset ◽  
Patrice Coddeville
Keyword(s):  
Transition Metals ◽  
Phosphate Buffer ◽  
Soluble Fraction ◽  
Certified Reference Materials ◽  
Health Effect ◽  
Oxidative Capacity ◽  
Pure Metal ◽  
Welding Fumes ◽  
Oxidative Potential ◽  
Potential Health

To evaluate the chemical behavior and the health impact of welding fumes (WF), a complex and heterogeneous mixture of particulate metal oxides, two certified reference materials (CRMs) were tested: mild steel WF (MSWF-1) and stainless steel WF (SSWF-1). We determined their total chemical composition, their solubility, and their oxidative potential in a phosphate buffer (PB) solution under physiological conditions (pH 7.4 and 37 °C). The oxidative potential (OPDTT) of WF CRMs was evaluated using an acellular method by following the dithiothreitol (DTT) consumption rate (µmol DTT L−1 min−1). Pure metal salts present in the PB soluble fraction of the WF CRMs were tested individually at equivalent molarity to estimate their specific contribution to the total OPDTT. The metal composition of MSWF-1 consisted mainly of Fe, Zn, Mn, and Cu and the SSWF-1 composition consisted mainly of Fe, Mn, Cr, Ni, Cu, and Zn, in diminishing order. The metal PB solubility decreased from Cu (11%) to Fe (approximately 0.2%) for MSWF-1 and from Mn (9%) to Fe (<1%) for SSWF-1. The total OPDTT of SSWF-1 is 2.2 times the OPDTT of MSWF-1 due to the difference in oxidative capacity of soluble transition metals. Cu (II) and Mn (II) are the most sensitive towards DTT while Cr (VI), Fe (III), and Zn (II) are barely reactive, even at higher concentrations. The OPDTT measured for both WF CRMs extracts compare well with simulated extracts containing the main metals at their respective PB-soluble concentrations. The most soluble transition metals in the simulated extract, Mn (II) and Cu (II), were the main contributors to OPDTT in WF CRMs extracts. Mn (II), Cu (II), and Ni (II) might enhance the DTT oxidation by a redox catalytic reaction. However, summing the main individual soluble metal DTT response induces a large overestimation probably linked to modifications in the speciation of various metals when mixed. The complexation of metals with different ligands present in solution and the interaction between metals in the PB-soluble fraction are important phenomena that can influence OPDTT depletion and therefore the potential health effect of inhaled WF.

Resorbable Metallic Implant: Findings from an Animal Model

2008 ◽  
Vol 47-50 ◽  
pp. 604-607
Author(s):  
C.K. Yuen ◽  
W.Y. Ip
Keyword(s):  
Rare Earth ◽  
Magnesium Alloys ◽  
Health Effect ◽  
Earth Metal ◽  
Corrosion Property ◽  
Gas Production ◽  
Exposure Level ◽  
Potential Health ◽  
Metallic Implant

Resorbable metallic implant of magnesium and its alloys had been studied since the 1900s. However, the excessive gas production resulted in its unpopularity after CoCr alloys and stainless steel were developed. With the advancement of alloying technologies, its use as a resorbable implant has re-emerged recently. Foreign researchers focused on the use of AZ-series and magnesium-rare earth metal alloys. However, the corrosion property of AZ-series alloys is unsatisfactory, and the effect of rare-earth metals on human is poorly studied. Therefore, we have investigated on the feasibility of using commercially available AM-series magnesium alloys. Previous researchers avoided this alloy series presumably because of the potential health effect of manganese, however our toxicological risk assessment revealed that the exposure level would be lower than the NOAEL (No Observable Adverse Effect Level), thus it is unlikely to cause any observable health effect on healthy individuals. Subcutaneous implantation of AM-series magnesium alloys into a mouse model for six months confirmed that, while all alloys tested showed slow corrosion and no observable in vivo toxicity, pitting corrosion did not occur for AM-series alloys but was frequent for AZ91D. This suggests that AM-series magnesium alloys are good candidates of resorbable metallic implants.

Diamonds are Forever and Zirconium is for Submarines

2013 ◽  
Author(s):  
Lars Öhrström
Keyword(s):  
Transition Metals ◽  
Periodic Table ◽  
Chemical Properties ◽  
Pure Metal ◽  
Cubic Zirconia ◽  
Love Story ◽  
Zirconium Silicate ◽  
Similar Chemical ◽  
Engagement Rings

The appearance of a diamond engagement ring in the long and convoluted love story between Botswana’s First Lady Detective, Mma Ramotswe, and the owner and brilliant mechanic of Tlokweng Road Speedy Motors, Mr J. L. B. Matekoni, seems to signal an end to this particular sub-plot, stretching over several volumes of Alexander McCall Smith’s bestselling and original series of crime novels (that we met in Chapter 1). However, a slight problem involving cubic zirconia is discovered, and the story lingers on until the next book in the series. Similar names for elements and their compounds are a nuisance in chemistry, but oft en arise historically, and zirconium is just one such example. Apart from the pure metal we have zircon and zirconia, all three of which have important applications. Zircon is zirconium silicate, with the formula ZrSiO4, and cubic zirconia is a special form of zirconium dioxide, ZrO2. The latter, as you may have guessed, is an excellent diamond substitute in, among other applications, engagement rings. We are not going to dwell on the details of the element zirconium, but you should know that within the Periodic Table it is located in the large middle chunk called the transition metals. You have probably heard of its cousin titanium, immediately above it, and a sibling, hafnium, straight down the ladder. Why do I call them siblings? Because in the Periodic Table elements in the same column tend to have similar chemical properties. In particular, in the family of transition metals in the central section containing 27 elements—each with a number of properties in common—the two lower elements in each column tend to be the most similar. The similar chemical properties of zirconium and titanium means that we can usually find zirconium where we mine the much more plentiful titanium, and also that once we have separated the titanium from zirconium there will be a small quantity of hafnium trailing along—an impurity that is much harder to get rid of. The sleek jeweller in Gaborone will not care if his fake diamonds contain trace levels of HfO2 mixed with the ZrO2.

Rat diaphragm during postnatal development. I. Changes in distribution of muscle fibre type and in oxidative potential

1996 ◽  
Vol 8 (3) ◽  
pp. 391 ◽  
Author(s):  
MD Fratacci ◽  
M Levame ◽  
A Rauss ◽  
H Bousbaa ◽  
G Atlan
Keyword(s):  
Muscle Fibre ◽  
Fibre Type ◽  
Oxidative Capacity ◽  
Cross Sectional Area ◽  
Fibre Types ◽  
Type I ◽  
Sectional Area ◽  
Rat Diaphragm ◽  
Oxidative Potential ◽  
Cross Sectional

The changes occurring in the histochemical characteristics of the rat diaphragm during the postnatal period were examined. Fibre-type distribution, fibre oxidative capacity, i.e. succinate-dehydrogenase (SDH) activity, and cross-sectional area were compared in the costal (COS) and crural (CRU) regions, and across their abdominal and thoracic surfaces. The proportions of type I and IIb fibres in both COS and CRU increased with age, while the proportion of type IIa fibres progressively decreased. For COS, fibre distribution was homogeneous over the entire muscle and did not change after 4 weeks. For CRU, it was heterogeneous with a higher proportion of type I fibres on the thoracic surface as from the first week. All fibre types significantly increased in cross-sectional area between 1 and 8 weeks, with no significant differences in COS and CRU. Mean SDH activity did not differ between COS and CRU or across the muscles. Mean SDH activities-were low and identical in all fibre types at birth, and then increased, peaking at the 6th week in type I and IIa fibres. When total muscle fibre oxidative capacity was calculated from an index including fibre-type proportion, cross-sectional area and mean SDH activity, it was significantly higher at 1 than at 8 weeks after birth; this might have functional implications for the newborn.

scholarly journals On dithiothreitol (DTT) as a measure of oxidative potential for ambient particles: evidence for the importance of soluble transition metals

2012 ◽  
Vol 12 (5) ◽  
pp. 11317-11350 ◽  
Author(s):  
J. G. Charrier ◽  
C. Anastasio
Keyword(s):  
Particulate Matter ◽  
Transition Metals ◽  
Fine Particulate Matter ◽  
Chemical Species ◽  
Past Research ◽  
Active Species ◽  
Oxidative Potential ◽  
Adverse Health Effects ◽  
Redox Active ◽  
Small Set

Abstract. The rate of consumption of dithiothreitol (DTT) is increasingly used to measure the oxidative potential of particulate matter (PM), which has been linked to the adverse health effects of PM. While several quinones are known to be very reactive in the DTT assay, it is unclear what other chemical species might contribute to the loss of DTT in PM extracts. To address this question, we quantify the rate of DTT loss from individual redox-active species that are common in ambient particulate matter. While most past research has indicated that the DTT assay is not sensitive to metals, our results show that seven out of the ten transition metals tested do oxidize DTT, as do three out of the five quinones tested. While metals are less efficient at oxidizing DTT compared to the most reactive quinones, concentrations of soluble transition metals in fine particulate matter are generally much higher than those of quinones. The net result is that metals appear to dominate the DTT response for typical ambient PM2.5 samples. Based on particulate concentrations of quinones and soluble metals from the literature, and our measured DTT responses for these species, we estimate that for typical fine particle samples approximately 80% of DTT loss is from transition metals (especially copper and manganese), while quinones account for approximately 20%. We find a similar result for DTT loss measured in a small set of PM2.5 samples from the San Joaquin Valley of California. Because of the important contribution from metals, we also tested how the DTT assay is affected by EDTA, a chelator that is sometimes used in the assay. EDTA significantly suppresses the response from both metals and quinones; we therefore recommend that EDTA should not be included in the DTT assay.

4 Final Report on the Safety Assessment of Butyl Stearate, Cetyl Stearate, Isobutyl Stearate, Isocetyl Stearate, Isopropyl Stearate, Myristyl Stearate, and Octyl Stearate

1985 ◽  
Vol 4 (5) ◽  
pp. 107-146 ◽  
Keyword(s):  
Safety Assessment ◽  
Animal Studies ◽  
Health Effect ◽  
Final Report ◽  
Cosmetic Products ◽  
Oral Toxicity ◽  
Potential Health ◽  
Rabbit Skin ◽  
Cosmetic Ingredients ◽  
Cosmetic Formulations

The 7 Stearates described in this report are either oily liquids or waxy solids that are primarily used in cosmetics as skin emollients at concentrations up to 25 percent. The toxicology of the Stearates has been assessed in a number of animal studies. They have low acute oral toxicity and are essentially nonirritating to the rabbit eye when tested at and above use concentration. At cosmetic use concentrations the Stearates are, at most, minimally irritating to rabbit skin. In clinical studies the Stearates and cosmetic products containing them were at most minimally to mildly irritating to the human skin, essentially nonsensitizing, nonphototoxic and nonphotosensitizing. Comedogenicity is a potential health effect that should be considered when the Stearate ingredients are used in cosmetic formulations. On the basis of the information in this report, it is concluded that Butyl, Cetyl, Isobutyl, Isocetyl, Isopropyl, Myristyl, and Octyl Stearate are safe as cosmetic ingredients in the present practices of use.

scholarly journals An Awareness Survey of Inhabitants Exposure to Radiological Impacts on Mines in Yauri LGA, Kebbi State, Nigeria

2018 ◽  
Vol 3 (11) ◽  
pp. 12-15
Author(s):  
Yusuf Musa Ahijjo ◽  
A. N. Baba-Kutigi ◽  
M. Momoh ◽  
A. M. Bayawa ◽  
M. Hussain
Keyword(s):  
Random Sampling ◽  
Health Effect ◽  
Mining Activities ◽  
Radioactive Elements ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Potential Health ◽  
Subsequent Issue ◽  
Near Future ◽  
Vegetation Samples

A cross-sectional survey was conducted in Yauri LGA, Kebbi State in between April, 2015 and January, 2016 in order to ascertain the level of awareness of inhabitant’s exposure to radioactivity from the mines. Yauri LGA was sampled based on its metropolitan and suburban parts that receives heavy mining activities by stratified random sampling by proportions. An interactive medium was created to sample the opinions of inhabitants around these mines through questionnaire. A total of 150 questionnaire were designed, 30 were accepted by the respondents and 22 were returned with response from the correspondents during the survey and interview to document and assessment awareness of the inhabitants. The study unveiled facts about the inhabitant’s awareness towards the environmental and health effect of indiscriminate mining activities around living places. The results shows that over 70% of the inhabitants within the suburb and metropolis concurred to the potential health consequences in their dwellings as a result of exposure to radioactivity from the mines respectively. These results indicates that the environmental and health discomfort due to indiscriminate mining activities around living places will be more significant in the near future if no immediate efforts are put in place to mimic future malady. The second aspect of this study whose results will be published in the subsequent issue involved collection of soil, water and vegetation samples in order to further assess the level of radioactive elements viz: 226Ra, 232Th and 40K occurrence in the study locality.

scholarly journals Protein Corona Hinders N-CQDs Oxidative Potential and Favors Their Application as Nanobiocatalytic System

2021 ◽  
Vol 22 (15) ◽  
pp. 8136
Author(s):  
Joanna Czarnecka ◽  
Mateusz Kwiatkowski ◽  
Marek Wiśniewski ◽  
Katarzyna Roszek
Keyword(s):  
Biomedical Applications ◽  
Catalytic Efficiency ◽  
Protein Corona ◽  
Immobilized Enzymes ◽  
Oxidative Capacity ◽  
Carbon Quantum Dots ◽  
Oxidative Potential ◽  
Corona Formation ◽  
High Concentrations ◽  
Enzyme Application

The oxidative properties of nanomaterials arouse legitimate concerns about oxidative damage in biological systems. On the other hand, the undisputable benefits of nanomaterials promote them for biomedical applications; thus, the strategies to reduce oxidative potential are urgently needed. We aimed at analysis of nitrogen-containing carbon quantum dots (N-CQDs) in terms of their biocompatibility and internalization by different cells. Surprisingly, N-CQD uptake does not contribute to the increased oxidative stress inside cells and lacks cytotoxic influence even at high concentrations, primarily through protein corona formation. We proved experimentally that the protein coating effectively limits the oxidative capacity of N-CQDs. Thus, N-CQDs served as an immobilization support for three different enzymes with the potential to be used as therapeutics. Various kinetic parameters of immobilized enzymes were analyzed. Regardless of the enzyme structure and type of reaction catalyzed, adsorption on the nanocarrier resulted in increased catalytic efficiency. The enzymatic-protein-to-nanomaterial ratio is the pivotal factor determining the course of kinetic parameter changes that can be tailored for enzyme application. We conclude that the above properties of N-CQDs make them an ideal support for enzymatic drugs required for multiple biomedical applications, including personalized medical therapies.

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