Small Amounts Of Chromium Research Articles

Development and evaluation of a novel chromium III-based compound for potential inhibition of emerging SARS-CoV-2 variants

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused 403 million cases of coronavirus disease (COVID-19) and resulted in more than 5.7 million deaths worldwide. Extensive research has identified several potential drug treatments for COVID-19. However, the development of new compounds or therapies is necessary to prevent the emergence of drug resistance in SARS-CoV-2. In this study, a novel compound based on hexaacetotetraaquadihydroxochromium(III)diiron(III) nitrate, which contains small amounts of chromium (III), was synthesised and evaluated for its effectiveness against multiple variants of COVID-19 using both in vitro and in vivo models. This innovative compound demonstrated interference with the interaction between the spike protein of SARS-CoV-2 and angiotensin-converting enzyme 2 (ACE2). Furthermore, in vitro experiments showed that this compound downregulated the expression of ACE2 and transmembrane serine protease 2 (TMPRSS2). It also exhibited a reduction in the activity of 3-chymotrypsin-like protease (3CL) and RNA-dependent RNA polymerase (RdRp). Pretreatment with this small chromium (III)-based compound resulted in reduced ACE2-rich cell infection by various variants of SARS-CoV-2 spike protein-pseudotyped lentivirus. Finally, the compound effectively inhibited viral infection by multiple variants of SARS-CoV-2 spike protein-pseudotyped lentivirus in both the abdominal and thoracic regions of mice. In conclusion, this compound lowers the likelihood of SARS-CoV-2 entry into cells, inhibits viral maturation and replication in vitro, and reduces infection levels of multiple variants of SARS-CoV-2 spike protein-pseudotyped lentivirus in the abdomen and thorax following pretreatment. Small chromium (III)-based compounds have the potential to restrict the progression of SARS-CoV-2 infections.

Effect of Chromium, Cadmium and Other Trace Metals on the Growth and Survival of Mice

Seven hundred weanling white mice were fed a diet of rye, corn oil and dried skim milk containing no detectable cadmium and only small amounts of chromium, titanium, lead and nickel. They were housed in quarters from which most contaminating metals were excluded. Groups of 100 or more animals were given 5 ppm of these metals in drinking water as soluble salts. Trivalent chromium increased the growth of both sexes and lessened the mortality of male animals up to 17 months of age. Tetravalent titanium increased growth, but did not significantly affect mortality. Divalent lead, nickel and cadmium had no marked effect on growth, mature weights nor mortalities up to 18 months of age, but after that, cadmium and lead significantly increased death rates in males when tissue levels were less than or equal to those of adult human beings. Mice “cadmium-free” by microanalytical methods (< 0.02 μg/g, wet tissue) grew normally and did not differ in any obvious way from those given the metal, except for prolonged survival of males. Chromium appears to act as an accessory trace metal for growth and survival while cadmium is not essential in these terms, having an innate “toxicity” similar to lead.

Effects of Chromium, Cadmium and Lead on the Growth and Survival of Rats

Eight groups of more than 50 hooded rats were each given (at 5 ppm) cadmium, trivalent chromium or lead in drinking water while fed a diet of rye flour, dried skim milk and corn oil containing no detectable cadmium and only small amounts of chromium and lead. Extensive precautions were taken to avoid environmental metallic contamination. The diet was nutritionally adequate for survival, all but 7 control animals surviving 21 months. Mortality of rats receiving chromium was equally low. Although those given lead and cadmium grew normally, survival was considerably reduced when their tissue concentrations of metal were approximately similar to or less than those of adult human beings. No metallic toxicity appeared. Growth of males was stimulated by chromium and mature animals were larger than the controls. Cadmium was not detected in the livers and kidneys of animals not given it, although they grew normally and survived. Cadmium is not an “essential” trace metal for rats in terms of growth and survival; it shortens their lives at less than human renal concentrations. Lead at human tissue concentrations has a similar innate toxicity in terms of survival. If chromium has a metabolic function, these experiments confine it to male rats.

Effect of composition and microstructure on the rusting of MS rebars and ultimately their impact on mechanical behavior

Rebar steel is used for reinforcement to aid concrete because concrete does not sustain tension. Thermomechanical treatment is an advanced manufacturing technique for rebar production, but rusting problems emerged in the local steel industry. Raw material sampling included ingot casting (IC) and continuous casting (CC). IC samples corroded more frequently than CC samples. Spectroscopy indicated a small amount of chromium and an improper ratio of manganese to sulfur in IC samples. The improper ratio of manganese to sulfur in IC samples promoted hot cracking at grain boundaries, which resulted in intergranular corrosion. The microstructural results of G40 (air cooled) and G60 (water cooled) showed ferrite and martensite in different proportions. The deformed ferrite in G60 indicated inclination to corrosion, and no proper stable layer of martensite was found. The percentage of martensite was not enough to retaliate against intergranular corrosion. Highly pressurized water initiated pitting corrosion due to the formation of small pits on the surface. Tensile testing revealed 10% reduction in ultimate strength, 8% reduction in yield strength, and 30% reduction in percentage of elongation of corroded samples. Environmental study revealed that the humidity level in the industry was greater than in the laboratory space. High values of SOxand NOxemission revealed the involvement of the environment in the deterioration of the product surface.

A Joining Process between Beryllium and Reduced-Activation Ferritic-Martensitic Steel by Plasma Sintering.

To investigate the growth kinetics of the reaction layer and mechanical strength of joined materials, we joined beryllium and reduced-activation ferritic–martensitic steel (F82H) by plasma sintering under various conditions and characterized the joined region. Scanning electron microscopy revealed that the thickness of the reaction layer increased with an increase in the joining time and temperature. Line analyses and elemental mapping using an electron microprobe analyser showed that the reaction layer consists of Be–Fe intermetallic compounds, including Be12Fe, Be5Fe, and Be2Fe, with small amounts of chromium and tungsten. Owing to the time and temperature dependence of the reaction-layer thickness, the layer growth of Be–Fe intermetallic compounds obeys the parabolic law, and the activation energy for the reaction-layer growth was 116.2 kJ/mol. The bonding strengths of the joined materials varied inversely with the thickness of the reaction layer.

High Temperature Corrosion Behaviors of 20G Steel, Hastelloy C22 Alloy and C22 Laser Coating under Reducing Atmosphere with H2S

High-temperature corrosion behaviors of 20G steel, Hastelloy C22 alloy and C22 laser coating was evaluated by corrosion mass gain measurements at 450 °C. The corrosive atmosphere is 0.2 vol% H2S–0.1 vol% O2–N2, which simulated the severe high-temperature corrosion environment occurred under low-NOx combustion in pulverized-coal furnaces. Experimental results showed that the corrosion resistance of the C22 laser coating and the C22 alloy was obviously better than 20G steel. Furthermore, it should be noted that the C22 laser coating fabricated in this study displayed a higher corrosion resistance than the commercial C22 alloy although they had the same chemical composition. The severe pitting corrosion was observed in 20G steel with the corrosion products consisting of FeS2, Fe2O3 and Fe3O4. The C22 alloy and C22 laser coating exhibited the uniform corrosion and their main corrosion products were NiS2, CrS and a small amount of chromium and manganese oxides.

Magnetic, Magnetoelastic and Corrosion Resistant Properties of (Fe-Ni)-Based Metallic Glasses for Structural Health Monitoring Applications.

We have performed a study of the magnetic, magnetoelastic, and corrosion resistance properties of seven different composition magnetoelastic-resonant platforms. For some applications, such as structural health monitoring, these materials must have not only good magnetomechanical properties, but also a high corrosion resistance. In the fabricated metallic glasses of composition , the Fe/Ni ratio was varied (Fe + Ni = 73% at.) thus changing the magnetic and magnetoelastic properties. A small amount of chromium was added in order to achieve the desired good corrosion resistance. As expected, all the studied properties change with the composition of the samples. Alloys containing a higher amount of than do not show magnetic behavior at room temperature, while iron-rich alloys have demonstrated not only good magnetic properties, but also good magnetoelastic ones, with magnetoelastic coupling coefficient as high as for in the (the sample containing only but not ). Concerning corrosion resistance, we have found a continuous degradation of these properties as the content increases in the composition. Thus, the corrosion potential decreases monotonously from 46.74 mV for the , composition to −239.47 mV for the , composition .

Managing Structure and Properties of Pipe Steel Alloyed with Chromium in the Process of Cooling After Thermomechanical Rolling

A study was conducted concerning the kinetics of phase transformations and structure of grade K60 (X70) pipe steels alloyed with small amounts of chromium (K60Cr) and molybdenum (K60Mo). It was shown that K60Mo steel differs by a higher structural content of M/A components. The laboratory tests and microstructure studies of the obtained samples by color etching, TEM, and XRD methods have shown that by using the improved cooling conditions after thermomechanical rolling of K60Cr steel, it becomes possible to obtain samples having different matrix microstructure (polygonal, quasi-polygonal, or bainitic ferrite) and various secondary phases (M/A or cementite), which yields different mechanical properties ranging from 467 to 633 MPa (yield point – σy ); 681 to 804 MPa (ultimate strength – σt ); 22 to 31.8% (percent elongation – δe); 8.8 to 17.4% (proportional elongation – δp); and 0.68 to 0.88 (σy /σt ratio). It was established that the presence of M/A component instead of cementite in the structure contributes to an increase in strength and decrease in σy /σt ratio without a considerable decline in cold resistance. At JSC “Vyksa Metallurgical Plant” (VMZ), K60Cr steel, which is more economical compared to K60Mo, and newly developed technology were used to produce commercial batches of rolled products and large diameter pipes, which demonstrated the specified σy /σt ratio and higher impact toughness and cold resistance values during a drop weight tear test (DWTT).

Failure analysis of titanium heater tubes and stainless steel heat exchanger weld joints in nitric acid loop

A 400 l capacity nitric acid loop (NAL) test facility simulating inactive plant operating conditions was designed, constructed and evaluation of candidate materials was carried out for nuclear spent fuel reprocessing applications. Austenitic stainless steel coupons were exposed to flowing nitric acid medium at various temperatures in NAL. Assessment of critical components of NAL after 10,000 h operation revealed failure of titanium heater tubes and stainless steel heat exchanger tube sheet welds. Failure analysis and detailed characterisation of corrosion products on the failed tubes were carried out using SEM, EDX and XRD techniques. The brown colour corrosion product on titanium heater tubes comprised iron and small amounts of chromium indicating that failure of titanium tubes was due to deposition of corrosion products of stainless steel, leading to galvanic corrosion. Cracks observed on titanium heater tubes were attributed to hydrogen-induced cracking, resulting in severe degradation. Surface morphology and EDX analysis of the corrosion product on stainless steel heat exchanger tubes revealed dislodged grains from 304LSS and XRD analysis confirmed the deposit as stainless steel. Grain dropping occurred due to intergranular corrosion of 304L SS in nitric acid and deposition of the dislodged grains at the seal weld joints resulted in localised corrosion and failure. Based on the studies carried out, surface heaters instead of immersion heaters and periodic inspection and frequent removal of corrosion products from the nitric acid loop were suggested to mitigate such failures. Based on the results of the investigation, repair and refurbishment of the nitric acid loop was undertaken.

Synthesis of Cr-doped Al2O3 by Pechini sol-gel method and its application for reversible thermochromic sensors

Abstract Aluminum oxide doped with a small amount of chromium is known as “ruby” or “ruby solution” and can be used as a thermochromic material. The Pechini sol-gel process is applied to synthesize this advanced material. The crystal structure, chemical composition, and morphology of the synthesized materials are analyzed using X-ray diffraction, scanning electron microscopy coupled with energy-dispersive X-ray spectrometry, and Fourier transform infrared (FT-IR) spectroscopy. The color performance of the synthesized material is analyzed using UV-VIS spectrometry. Finally, the thermochromism exhibited by the pigment powders at high temperatures is investigated. The pigment exhibits exceptional thermochromic properties, transitioning from pink to gray in a temperature range of 25–600 °C. The change in color is reversible and is dependent on the temperature and chromium concentration; however, it is independent of the exposure time. This novel property of Cr-doped Al2O3 can be potentially employed in reversible thermochromic sensors that could be used not only for warning users of damage due to overheating when the environmental temperature exceeds certain limits, but also for detecting and monitoring the temperature of various devices, such as aeronautical engine components, hotplates, and furnaces.

Effect of the Cobalt Content and Chromium Alloying on the Structure of the Scale Formed on Structural β-NiAl + γ'-Ni3Al + γ-Ni Alloys (Ni–Al–Co System) at 1300°C

The structures of the scale and the subscale layers that form during the air oxidation of the β + γ' + γ alloys of the Ni–Al–Co system containing (at %) ~27 Al (alloys 1–3), 10 Co (base alloy 1), 16 Co (alloy 2), and 10 Co and 4.25 Cr (alloy 3) at 1300°C for 100 h are studied. The formation of scale (Al2O3) in all alloys leads to the aluminum depletion of the subscale layers and to the γ' → γ + γ' transition due to the interdiffusion of aluminum and oxygen. An increase in the cobalt content from 5 to 10 at % increases the heat resistance. The degradation of the heat resistance induced by an increase in the cobalt content to 16 at % is related to an increase in the volume fraction of the γ phase in an alloy as compared to the base alloy with 10 at %. The introduction of small amounts of chromium degrades the heat resistance because of the development of internal oxidation, i.e., the penetration of alumina into an alloy along interdendritic γ-phase precipitates. The heat resistance of the chromium-free β + γ' + γ alloy with 10 at % Co at 1300°C, which was estimated from the sample mass increment per unit surface area in 100 h, is higher than the heat resistance of the well-known γ' + γ VKNA and VIN alloys at 1100–1200°C.

Cr(OH)3-NPs-CNC hybrid nanocomposite: a sorbent for adsorptive removal of methylene blue and malachite green from solutions.

In this article, Cr(OH)3 nanoparticle-modified cellulose nanocrystal (CNC) as a novel hybrid nanocomposite (Cr(OH)3-NPs-CNC) was prepared by a simple procedure and used as a sorbent for adsorptive removal of methylene blue (MB) and malachite green (MG) from aqueous solution. Different kinetic models were tested, and the pseudo-second-order kinetic model was found more suitable for the MB and MG adsorption processes. The BET and Langmuir models were more suitable for the adsorption processes of MB and MG. Thermodynamic studies suggested that the adsorption of MB and MG onto Cr(OH)3-NPs-CNC nanocomposite was a spontaneous and endothermic process. The maximum adsorption capacities for MB and MG were reached 106 and 104mg/g, respectively, which were almost two times higher than unmodified CNC. The chemical stability and leaching tests of the Cr(OH)3-NPs-CNC hybrid nanocomposite showed that only small amounts of chromium were leached into the solution.

¬¬Chromium fluoride-containing bioactive glasses: Structure and properties

Bioglasses in the system 24.5Na2O.24.5CaO.6P2O5.xCrF2.(45-x)SiO2 have been studied in the composition region of x= 0-10 mol%. CrF2. Glass of molar ratio (Ca+Na)/SiO2 ~1.1 is the base material for the glasses containing different CrF2 concentrations. X-ray diffraction (XRD), differential scanning calorimetriy (DSC), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Vicher hardness (Hv) measurements have been carried out. Crystalline feature of the glasses is followed up by XRD spectroscopy. It is found that crystallinity was enhanced via CrF2 addition. More enhancement was confirmed via thermal heat treatment process. Increasing CrF2 and sintering temperature will induce new ordered phases which will be distributed in the main glassy phase. Well formed flouroapatite (Ca5(PO4)3F and wollastonite Ca3Cr2(SiO4)3 phases containing fluorine and chromium ions are evidenced in CrF2 containing glasses. Increasing glass transition temperature Tg and hardness number Hv upon increasing CrF2 concentration was discussed on bases of formation of additional bonds by the effect of CrF2 molecules. The measured temperature window between Tc and Tg was found to have a great influence in material structure. Wide window is a feature of amorphous glass which free from CrF2. The window scale is found to quickly decrease with increasing CrF2, since crystalline phases are already formed in glasses containing CrF2. Formation of crystalline intermediate phases with more shielded silicate and phosphate structural is considered as the main reason for increasing Tg and (Hv) of the glasses. EDS as well as XRD analyzed spectra confirm that crystalline wollastonite of calcium inosilicate mineral (CaSiO3) phase is well formed. The wollastonite species is evidenced to contain small amounts of chromium and fluorine ions which are substituting for calcium cations. Wollastonite phases with Cr/Si=1 is the most dominant type. This ratio is a characteristic feature of crystalline CaSiO3 species. Small concentration from fluorine ions are involved in apatite phases. Presence of both crystalline apatite and wollastonite in the sample matrix promotes its biocompatibility, particularly orthopedic bioactivity. As a consequence, some of investigated glasses are recommended to be applicable in dental field of applications. This depends on its own crystallinity, hardness, its apatite and wollastonite concentration as biocompatible phases in the crystallized glass

Degradation of La0.6Sr0.4Co0.2Fe0.8O3–δ–Ce0.8Sm0.2O1.9 Cathodes on Coated and Uncoated Porous Metal Supports

AbstractThe degradation of composite LSCF‐SDC cathodes on porous 430 stainless steel supports was investigated. Two degradation mechanisms were observed: a multi‐layer oxide scale, believed to consist of Cr2O3 and SrCrO4, formed at the support‐cathode interface, and small amounts of chromium were detected within the cathodes. To reduce degradation, La2O3 and Y2O3 reactive element oxide coatings were deposited on the internal pore surfaces of the metal supports. The reactive element oxide coatings reduced the amount of volatile chromium that deposited in the cathodes. As a result, the degradation rates of the cathodes on coated supports were significantly lower than the degradation rates of cathodes made on uncoated metal supports. In cathode symmetrical cells, polarization resistance degradation rates as low as 2.56 × 10−6 Ω cm2 h−1 were observed over 100 hours on coated metal supports, compared to an average of 1.23 × 10−4 Ω cm2 h−1 on uncoated supports.

탄소강의 유동가속부식에 미치는 크롬의 영향

The alloy content of structural materials of nuclear power plants has been recognized an important factor in predicting flow accelerated corrosion (FAC). In particular, many literature data reported that chromium content is one of the most important alloying element and even a small amount of chromium is effective to suppress FAC. This report reviewed and compared chromium models of Ducreux, Bouchacourt, and Kastner which were used in predicting FAC rates. The plant data indicate that Ducreux model may be conservative for the specimen containing 0.15 wt% chromium. The related articles were reviewed as follows. Combined effects of chromium content, pH, temperature, dissolved oxygen (DO), flow velocity, test time, and kinds of amine on the FAC rate were described. 0.1 wt% chromium in steel did not affect the FAC rate with changes in pH. The FAC rates pronounced with higher flow rate and increased with increasing test duration(600 d) for 0.013 wt% chromium. The FAC rates in mixed amine chemistry were higher than in ammonia chemistry, which may be lessened by the addition of chromium to the steel.

Chromium 3+ as a therapy for diabetes type 2 (828.1)

Chromium in the +3 oxidative state is an essential and important form metabolically Chromium forms very stable complexes with water (5 x 10‐7 M‐1s‐1), urea, ammonia, halides, sulfate and organic acids. Chromium's major function is in proper glucose utilization by establishing stable complexes with glutamic acid residues in insulin, in a chaperone located between the insulin and insulin receptor. The insulin receptor will open a glucose channel in the cell membrane and thus allow the glucose to enter the cell to be metabolized by glycolysis. Only small amounts of chromium are required, less than 1 % of dietary chromium is absorbed and retained. The chaperone has been isolated from liver and kidney of several mammalian species and bovine colostrum. The chaperone is composed of glycine, cysteine, aspartate and glutamate in a molar ratio of 2:2:2:4 and has a molecular weight of ~1500.The combination of insulin, chaperone and insulin receptor are the functional aspects of the receptor. Chaperone and insulin require stability for activation of tyrosine kinase for the process of providing the means to transport glucose into the metabolic cells for metabolism to energy and the provision of carbon segments for other metabolic entities. Though the number of human test subjects is small, it has been demonstrated that Diabetes Type 2 can be effectively treated as a chromium deficiency.

Effects of pressure and temperature on sintering of Cr-doped Al2O3 by pulsed electric current sintering process

The aluminium oxide crystal, Al2O3, which contains a small amount of chromium, Cr, is called ruby. Pulsed electric current sintering (PECS) was applied to sinter ruby polycrystals. Cr2O3-Al2O3 powder mixture prepared by drying an aqueous slurry containing amounts of Al2O3 and Cr(NO3)3 was consolidated by PECS process. The PECS process was performed in vacuum at sintering temperature raging from 1100 to 1300°C with heating rate of 2 K/min under applied uniaxial pressure varied from 40 to 100 MPa. This study found that highly densified and transparent Cr-doped Al2O3 can be obtained by the PECS process with the high applied pressure at sintering temperature of 1200°C.

Influence of individual Cr–C layer thickness on structural and tribological properties of multilayered Cr–C/a-C:Cr thin films

Abstract Multilayered Cr–C/a-C:Cr thin films were prepared by using a hybrid technique of combined vacuum cathodic arc/magnetron sputtering/ion beam deposition. The multilayered films consisted of a dense gradient base layer and 10 bi-layers of Cr–C (chromium matrix containing some carbon) and a-C:Cr (amorphous carbon matrix containing a small amount of chromium). The thickness of individual a-C:Cr layer was kept constant at about 18.5 nm, while that of individual Cr–C layer varied from 11.1 to 55.1 nm. It was found that an increase of the individual Cr–C layer thickness from 11.1 to 40 nm resulted in increase in material nanohardness from 7.6 to 13.6 GPa and Young's modulus from 107 to 164.8 GPa. However, a further increase in the individual Cr–C layer thickness to 55.1 nm led to decrease in nanohardness to 9.5 GPa and Young's modulus to 142.4 GPa. The scratch tests indicate that the adhesion strengths between the films and substrates are dramatically improved through the multilayered structure, acquiring critical loads exceeding 80 N. The results of pin-on-disk tests show that the lowest wear rate 1.35 × 10 − 6 mm 3 /Nm was achieved from the coated sample with the individual Cr–C layer thickness of about 40 nm.

Effect of Alloying Elements on Tensile Properties, Microstructure, and Corrosion Resistance of Reinforcing Bar Steel

The effect of copper, phosphorus, and chromium present in a semikilled reinforcing bar steel produced by in-line quenching [thermomechanical treatment (TMT)] process on the tensile properties, microstructure, and corrosion resistance of steel in simulated chloride environment has been investigated. The results have been compared with that of a semikilled C-Mn reinforcing bar steel without these alloying elements produced by the same process route. Though the amount of phosphorus (0.11 wt.%) was higher than that specified by ASTM A 706 standard, the Cu-P-Cr steel exhibited a composite microstructure, and good balance of yield stress, tensile stress, elongation, and ultimate tensile to yield stress ratio. Two conventional test methods, namely, the salt fog, and potentiodynamic polarization tests, were used for the corrosion test. The rust formed on Cu-P-Cr steel was adherent, and was of multiple colors, while the corrosion products formed on the C-Mn steel were weakly adherent and relatively darker blue. Also, the free corrosion potential of the Cu-P-Cr steel was nobler, and the corrosion current was markedly lower than that of a C-Mn rebar. The Cu-P-Cr steel did not develop any pits/deep grooves on its surface even after the prolonged exposure to salt fog. The improved corrosion resistance of the Cu-P-Cr steel has been attributed to the presence of copper, phosphorus, and small amount of chromium in the dense, adherent rust layer on the surface of reinforcing steel bar. A schematic mechanism of charge transfer has been proposed to explain the improved corrosion resistance of the Cu-P-Cr alloyed TMT rebar.

Microelectrochemical Investigation on Pit Initiation at Sulfide and Oxide Inclusions in Type 304 Stainless Steel

MnS and MnO inclusions with a small amount of chromium were obtained by heat-treatments of Type 304 stainless steel at 1353, 1573, and , and the anodic dissolution behavior of the inclusions was investigated using a microelectrochemical technique. In the case of the sulfide inclusions, those with a high dissolution potential were found to provide high pitting potentials in the macroscopic measurements in NaCl. The initiation sites of metastable and stable pits were at the boundaries of the inclusions and the matrix in NaCl, , and LiCl. The dissolution current densities on the inclusion surface at the moment of the initiation of a stable pit decreased with increasing chloride-ion concentration. The synergistic effect of chloride ions and sulfur-containing species released from the inclusions was thought to play an important role in the pit-initiation process. The oxide inclusions did not dissolve in the passive region of Type 304 stainless steel. In the solutions with chloride-ion concentrations of up to , pitting did not occur at the oxide inclusions in microscopic polarization measurements. The oxide inclusions exhibited a comparatively inert characteristic as pit-initiation sites.