Nickels and tines: the myth of nickel allergy in intracranial stents

BackgroundMost intracranial stents contain nickel alloy, and nickel allergy or hypersensitivity is common. Neurological injury following endovascular treatment with a nickel containing intracranial stent has been reported in patients with purported nickel allergy, but it is unclear whether these reactions represent true nickel hypersensitivity. We quantified nickel release from commonly used intracranial stents to investigate whether such stents should be avoided in patients with nickel allergy.MethodsWe examined nickel release from seven commonly used intracranial stents: Enterprise, LVIS Jr, Neuroform, Wingspan, Zilver, Pipeline Flex Embolization Device, and Surpass Evolve. We incubated each stent in human plasma-like media for 30 days. Dimethylglyoxime (DMG) spot testing was performed on each stent to detect released nickel at 0 and 30 days. Inductively coupled plasma–optical emission spectroscopy (ICP-OES) was then used to quantify the nickel concentration of the media at 30 days. Nickel currency and nickel standard for atomic absorption spectrometry were used as positive controls.ResultsDMG spot tests indicated nickel release only from nickel currency at 0 and 30 days of incubation. No nickel release was detected from any stent at 30 days using ICP-OES.ConclusionsNickel release from commonly used intracranial stents is negligible. These results suggest that previously reported hypersensitivity to these stents may be misattributed to nickel allergy, and that patients with nickel allergy may be safely treated with select nickel-containing stents.

Impurity Defect Induced Ferromagnetism Investigation of SiO2-Supported NiO Particles

This study examines amorphous SiO2-supported NiO particles by nickel concentration and calcination temperature arrangement to determine photoluminescence emission peaks and magnetic properties. Conventional co-precipitation with thermal calcination was used to produce NiO nanoparticles. Cubic NiO crystallization with single phase was improved by doubling the nickel concentration by calcination at 500 ºC and 600 ºC. Average crystalline size of 72 nm was obtained in the samples where double nickel concentration with calcination temperature at 600 ºC. Granular forms have been observed in all samples, and nickel clusters were shown in the samples where the nickel concentration is twice as high. Green band emission intensity increases with improved NiO crystallinity due to surface oxygen vacancies at 505 nm. It is interesting to observe ferrimagnetism for SiO2-supported NiO particles calcined at 500 ºC. From these results, optimal synthesis procedure and reduction in nucleation growth of NiO nanoparticles was achieved by double nickel concentration with calcination temperature at 600 ºC. Resumen. Este estudio examina partículas de NiO soportadas en SiO2. El estudio comprende la variación de la concentración de níquel y la temperatura de calcinación para determinar los picos de emisión de fotoluminiscencia y las propiedades magnéticas. Se utilizó la coprecipitación convencional con calcinación para producir nanopartículas de NiO. Se mejoró la cristalización cúbica de NiO con fase única al duplicar la concentración de níquel y calcinación a 500 ºC y 600 ºC. Se obtuvo un tamaño cristalino promedio de 72 nm en las muestras donde se duplicó la concentración de níquel con temperatura de calcinación a 600 ºC. Se observaron formas granulares en todas las muestras, y se encontraron agregados de níquel en las muestras donde la concentración de níquel fue el doble. La intensidad de la banda de emisión aumenta con la cristalinidad de NiO debido a las vacantes de oxígeno en la superficie. Es interesante observar el ferrimagnetismo de las partículas de NiO soportadas en SiO2 calcinadas a 500 ºC. A partir de estos resultados, se logró un procedimiento de síntesis óptimo y la reducción del crecimiento de nucleación de nanopartículas de NiO mediante una concentración doble de níquel con una temperatura de calcinación de 600 ºC.

Impact On Vegetables Irrigated With Municipal and Industrial Wastewater From Korangi Drain Near IoBM, Karachi

The present study was conducted to assess the Impact on Vegetables Irrigated with Municipal and Industrial wastewater from Korangi Drain near IoBM, Karachi. Some vegetables are grown using sewage and industrial wastewater laden with alarmingly high levels of heavy metals and bacteriological contamination. Maximum concentration of lead was found in spinach 8.20 mg/l as against safe limits of 0.01 mg/l and maximum Nickel concentration was found in banana 3.114 mg/l as against 0.02mg/l whereas all vegetables were invariably bacteriologically contaminated much beyond safe limits. Appropriate legislations in Sindh and competent manpower for rigorous monitoring to gage the harmful impact on vegetables grown with untreated municipal and industrial wastewater to effectively combat the problems of growing vegetables. The emptying of untreated municipal and industrial wastewater through Korangi Drain in fresh water bodies into Karachi cost should be banned to save the coast becoming hypoxic causing irreparable loss to marine life.

Effect of Nickel as Stress Factor on Phenol Biodegradation by Stenotrophomonas maltophilia KB2

This study focuses on the phenol biodegradation kinetics by Stenotrophomonas maltophilia KB2 in a nickel-contaminated medium. Initial tests proved that a nickel concentration of 33.3 mg·L−1 caused a cessation of bacterial growth. The experiments were conducted in a batch bioreactor in several series: without nickel, at constant nickel concentration and at varying metal concentrations (1.67–13.33 g·m−3). For a constant Ni2+ concentration (1.67 or 3.33 g·m−3), a comparable bacterial growth rate was obtained regardless of the initial phenol concentration (50–300 g·m−3). The dependence µ = f (S0) at constant Ni2+ concentration was very well described by the Monod equations. The created varying nickel concentrations experimental database was used to estimate the parameters of selected mathematical models, and the analysis included different methods of determining metal inhibition constant KIM. Each model showed a very good fit with the experimental data (R2 values were higher than 0.9). The best agreement (R2 = 0.995) was achieved using a modified Andrews equation, which considers the metal influence and substrate inhibition. Therefore, kinetic equation parameters were estimated: µmax = 1.584 h−1, KS = 185.367 g·m−3, KIS = 106.137 g·m−3, KIM = 1.249 g·m−3 and n = 1.0706.

Synthesis and Fabrication of Co1−xNixCr2O4 Chromate Nanoparticles and the Effect of Ni Concentration on Their Bandgap, Structure, and Optical Properties

In the present work, cobalt-chromite-based pigment Co1-xNixCr2O4 chromate powder and nanoparticles with various transition metal concentrations (x = 0.2, 0.4, 0.6, and 0.8) were manufactured by applying aqueous synthesis approaches and sol–gel synthesis routes. XRD analysis of the powder shows that all samples formulated by the sol–gel method were crystalline with a spinel structure. Chromites show green color with a higher nickel concentration, while Co-substituent shows blackish pigments. Samples were annealed at distinct temperatures ranging from 600 °C to 750 °C. The nanoparticles obtained were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy (RS), photoluminescence (PL), and energy-dispersive X-ray spectroscopy (EDS). The particle size of the parent compound (CoCr2O4) ranges from 100 nm to 500 nm, as measured by SEM. The tendency of particles to form aggregates with increasing annealing temperature was observed. These compounds may be successfully used as an effective doped nickel-cobalt ceramic pigment.

Structural, Morphological, and Magnetic Properties of Nickel Substituted Cobalt Zinc Nanoferrites at Different Sintering Temperature

Co-precipitation was used for the preparation of Co0.5-xNixZn0.5Fe2O4 (x = 0 to 0.3) nanoferrites. The inverse spinel structure of the samples was clearly shown by the structural analysis of X-ray Diffractometer (XRD) and Fourier Transform Infrared (FTIR) Spectroscopy. We have studied the effect of sintering temperature (500oC) on the lattice constant and particle size using XRD. The average lattice parameters for the non-sintered and sintered samples were 8.377 Å and 8.354 Å respectively. For the non-sintered sample, the nickel concentration decreases the lattice parameter from 8.354 Å to 8.310 Å due to its smaller ionic radii than that of cobalt. While for a sintered sample at 500oC, the lattice parameter increases for concentration x=0.3 due to the thermal effect. The particle size calculated by Transmission Electron Microscope (TEM) agrees well with that of XRD. The morphological and compositional analysis was done with the help of Scanning Electron Microscopy (SEM) and the attached Energy Dispersive X-ray (EDX) Analyzer. The increasing percentage of nickel with decreasing percentage of cobalt shows that the cobalt is substituted by Nickel. The magnetic properties were studied by Vibrational Spectrometer (VSM). The value of saturation magnetization is higher for x=0.1 but lower for x=0.2 and 0.3 due to their particle size. The hysteresis loop of the samples their superparamagnetic behavior at room temperature.

Influence of nickel doping on MnO2 nanoflowers as electrocatalyst for oxygen reduction reaction

Doping is promising strategy for the alteration of nanomaterials to enhance their optical, electrical, and catalytic activities. The development of electrocatalysts for oxygen reduction reactions (ORR) with excellent activity, low cost and durability is essential for the large-scale utilization of energy storage devices such as batteries. In this study, MnO2 and Ni-doped MnO2 nanowires were prepared through a simple co-perception technique. The influence of nickel concentration on electrochemical performance was studied using linear sweep voltammetry and cyclic voltammetry. The morphological, thermal, structural, and optical properties of MnO2 and Ni-doped MnO2 nanowires were examined by SEM, ICP-OES, FT-IR, XRD, UV–Vis, BET and TGA/DTA. Morphological analyses showed that pure MnO2 and Ni-doped MnO2 had flower-like and nanowire structures, respectively. The XRD study confirmed the phase transformation from ε to α and β phases of MnO2 due to the dopant. It was also noted from the XRD studies that the crystallite sizes of pure MnO2 and Ni-doped MnO2 were in the range of 2.25–6.6 nm. The band gaps of MnO2 and 0.125 M Ni-doped MnO2 nanoparticles were estimated to be 2.78 and 1.74 eV, correspondingly, which can be seen from UV–Vis. FTIR spectroscopy was used to determine the presence of functional groups and M–O bonds (M = Mn, Ni). The TGA/TDA examination showed that Ni-doping in MnO2 led to an improvement in its thermal properties. The cyclic voltammetry results exhibited that Ni-doped MnO2 nanowires have remarkable catalytic performance for ORR in 0.1 M KOH alkaline conditions. This work contributes to the facile preparation of highly active and durable catalysts with improved catalytic performance mainly due to the predominance of nickel. Article Highlights MnO2 and Ni-doped MnO2 nanowires were synthesized via a facile co-perception approach. Nickel doping in MnO2 induces the formation of wire-like nanostructures. Nickel doping enhances the electrochemical activity and thermal stability of MnO2 nanoflowers. The addition of nickel into MnO2 promoted the catalytic activity for oxygen reduction reaction. A higher catalytic activity was achieved in 0.125 M Ni-MnO2 nanowires. Graphic abstract

Evaluation of Lead, Cadmium and Nickel Contamination in Lactuca Sativa Cultivated in Savadkooh Region, Iran

Aims: To investigate the level of heavy metal contamination in the lettuce cultivated in Place: Savadkooh County in Mazandaran, Iran. Methodology: five samples were taken from the lettuce produced in this area and also from the soils in which they were cultivated, and the concentrations of Nickel, Lead, and Cadmium were measured by atomic absorption spectrometry. Descriptive and inferential statistics were used to analyze the measured data. Data analysis was performed by SPSS ver.16 at the 0.05 significance level. Results: The highest lead concentration, 0.07ppm, was observed in the sample No. 5 (Lettuce 5), the highest cadmium concentration, 0.008ppm, was measured in the sample No. 2 (Lettuce 2), and the highest nickel concentration, 0.07ppm, was observed in the samples No. 1 and 4 (Lettuce 1 and Lettuce 4). Conclusion: The results of this study show that while all the lettuces cultivated in the Savadkooh region contain some amounts of nickel, cadmium, and lead, these amounts are much lower than the limits specified in Iran’s national standard, and therefore these products are perfectly safe to consume. Also, the concentration of each heavy metal in the lettuces was found to be directly correlated with the corresponding concentration in the soil in which they were grown, indicating that the heavy metal content of the products increases with the increasing heavy metal content of the soil.