Concentrations Of NiCl2 Research Articles

Low-temperature controlled synthesis of Ni3S4/NiS2 composite powder in deep eutectic solvent

Ni3S4/NiS2 composite powder with controllable morphology and proportion is synthesized without using any surfactant in choline chloride-ethylene glycol (ChCl-EG) deep eutectic solvent (DES) at 120 °C. The products are characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) to reveal the effects of reaction time, and reactant concentration on their composition and structure. The reaction mechanism for synthesizing Ni3S4/NiS2 in ChCl-EG DES is also elaborated. The results show that different proportions of wrinkled, lamellar and layer-rolled Ni3S4/NiS2 can be obtained by controlling the concentration of NiCl2·6H2O and Na2S2O3·5H2O. The analysis found that the reaction mechanism of Ni3S4/NiS2 is Ni(II) reacting with S2O32− and H2O to form Ni3S4, NiS2, SO42−, and H+. The NMR hydrogen spectrum (1H NMR), NMR carbon spectrum (13C NMR) and FT-IR tests of ChCl-EG indicate that it is structurally stable, and acted as a solvent and template during the reaction process.

Nickel chloride generates cytotoxic ROS that cause oxidative damage in human erythrocytes

BackgroundNickel is a heavy metal that is regarded as a possible hazard to living organisms due to its toxicity and carcinogenicity. Nickel chloride (NiCl2), an inorganic divalent Ni compound, has been shown to cause oxidative stress in cells by altering the redox equilibrium. We have investigated the effect of NiCl2 on isolated human erythrocytes under in vitro condition. MethodsIsolated erythrocytes were treated with different concentrations of NiCl2 (25–500 µM) for 24 h at 37 ºC. Hemolysates were prepared and several biochemical parameters were analyzed in them. ResultsTreatment of erythrocytes with NiCl2 enhanced the intracellular generation of reactive oxygen species (ROS). A significant increase in hydrogen peroxide levels and oxidation of proteins and lipids was also seen. This was accompanied by a reduction in levels of nitric oxide, glutathione, free amino groups and total sulfhydryl groups. NiCl2 treatment impaired both enzymatic and non-enzymatic defense systems, resulting in lowered antioxidant capacity and diminished ability of cells to quench free radicals and reduce metal ions. NiCl2 exposure also had an inhibitory effect on the activity of enzymes involved in pathways of glucose metabolism (glycolytic and pentose phosphate shunt pathways). Increased level of methemoglobin, which is inactive in oxygen transport, was also seen. The rate of heme breakdown increased resulting in the release of free iron. Exposure to NiCl2 led to considerable cell lysis, indicating damage to the erythrocyte membrane. This was supported by the inhibition of membrane bound enzymes and increase in the osmotic fragility of NiCl2 treated cells. NiCl2 treatment caused severe morphological alterations with the conversion of normal discocytes to echinocytes. All changes were seen in a NiCl2 concentration-dependent manner. ConclusionNiCl2 generates cytotoxic ROS in human erythrocytes which cause oxidative damage that can decrease the oxygen carrying capacity of blood and also lead to anemia.

Relaxation measurements of an MRI system phantom at low magnetic field strengths

ObjectiveTemperature controlled T1 and T2 relaxation times are measured on NiCl2 and MnCl2 solutions from the ISMRM/NIST system phantom at low magnetic field strengths of 6.5 mT, 64 mT and 550 mT.Materials and methodsThe T1 and T2 were measured of five samples with increasing concentrations of NiCl2 and five samples with increasing concentrations of MnCl2. All samples were scanned at 6.5 mT, 64 mT and 550 mT, at sample temperatures ranging from 10 °C to 37 °C.ResultsThe NiCl2 solutions showed little change in T1 and T2 with magnetic field strength, and both relaxation times decreased with increasing temperature. The MnCl2 solutions showed an increase in T1 and a decrease in T2 with increasing magnetic field strength, and both T1 and T2 increased with increasing temperature.DiscussionThe low field relaxation rates of the NiCl2 and MnCl2 arrays in the ISMRM/NIST system phantom are investigated and compared to results from clinical field strengths of 1.5 T and 3.0 T. The measurements can be used as a benchmark for MRI system functionality and stability, especially when MRI systems are taken out of the radiology suite or laboratory and into less traditional environments.

N-acetyl-L-cysteine alleviated the oxidative stress-induced inflammation and necroptosis caused by excessive NiCl2 in primary spleen lymphocytes.

Nickel (Ni) is widely used in industrial manufacturing and daily life due to its excellent physical and chemical properties. However, Ni has the potential to harm animals' immune system, and spleen is a typical immune organ. Therefore, it is crucial to understand the mechanism of NiCl2 damage to the spleen. The purpose of this study is to investigate the effects of different concentrations of NiCl2 exposure and intervening with strong antioxidants on spleen lymphocytes to better understand the damage mechanism of Ni on spleen lymphocytes. In this experiment, mice spleen lymphocytes were used as the research object. We first measured the degree of oxidative stress, inflammation, and necroptosis caused by different NiCl2 concentrations. Subsequently, we added the powerful antioxidant N-acetyl-L-cysteine (NAC) and used hydrogen peroxide (H2O2) as the positive control in subsequent experiments. Our findings demonstrated that NiCl2 could cause spleen lymphocytes to produce a large number of reactive oxygen species (ROS), which reduced the mRNA level of antioxidant enzyme-related genes, the changes in GSH-PX, SOD, T-AOC, and MDA, the same to the mitochondrial membrane potential. ROS caused the body to produce an inflammatory response, which was manifested by tumor necrosis factor (TNF-α) in an immunofluorescence experiment, and the mRNA level of related inflammatory genes significantly increased. In the case of caspase 8 inhibition, TNF-α could cause the occurrence of necroptosis mediated by RIP1, RIP3, and MLKL. AO/EB revealed that spleen lymphocytes exposed to NiCl2 had significant necroptosis, and the mRNA and protein levels of RIP1, RIP3, and MLKL increased significantly. Moreover, the findings demonstrated that NAC acted as an antioxidant to reduce oxidative stress, inflammation, and necroptosis caused by NiCl2 exposure. Our findings showed that NiCl2 could cause oxidative stress, inflammation, and necroptosis in mice spleen lymphocytes, which could be mitigated in part by NAC. The study provides a point of reference for understanding the toxicological effect of NiCl2. The study suggests that NAC may be useful in reducing the toxicological effect of NiCl2 on the immune system. The research may contribute to the development of effective measures to prevent and mitigate the toxicological effects of NiCl2 on the immune system.

Double surface modification of graphite felt using a single facile step for electrolytic hydrogen production assisted by urea

Graphite felt (GF) is modified electrochemically using a facile controllable method via scanning the potential from +2 to ‒1.5 V in solutions containing various NiCl2 concentrations. By increasing the NiCl2 amount, the anodic oxidation and cathodic deposition processes are enhanced, and the GF surface is simultaneously functionalized. Firstly, at a high positive potential, GF’ functionalization occurs by making a defect in the carbon framework. Then, at a high negative potential, the rate of hydrogen evolution increases and produces a strong homogeneously uniform Ni(OH)2 coating at the GF surface. Modified GF is examined by SEM, mapping EDX, HR-TEM, XPS, XRD, Raman, and contact angle measurements. Interestingly, the Ni(OH)2 film deposited at GF from 100 mM NiCl2 solution (Ni(OH)2/GF-100) enhances the hydrogen evolution reaction in alkaline medium by deriving a current density of 10 mA cm−2 at a low overpotential of 69 mV which approaches the value of the benchmark catalyst. Additionally, the Ni(OH)2/GF-100 electrode supports urea oxidation as it drives a current density of 10 mA cm−2 at a potential of 1.38 V vs RHE. Therefore, Ni(OH)2/GF-100 is used as a bifunctional catalyst to replace the unfavourable anodic reaction (oxygen evolution reaction) with urea oxidation. Furthermore, a two electrode cell for urea electrolysis displays a cell voltage of 1.47 V, which is lower than that of water splitting by about 270 mV, to drive a current density of 10 mA cm−2 and shows superb stability over a prolonged electrolysis time of 24 h. So, this approach introduces an energy-saving route.

Nickel oxide thin film electrode synthesized by pneumatic spray pyrolysis with different NiCl2 concentration

Nickel oxide thin film electrode synthesized by pneumatic spray pyrolysis with different NiCl2 concentration

Lignin-containing hydrogels with anti-freezing, excellent water retention and super-flexibility for sensor and supercapacitor applications

We developed a highly conductive and flexible, anti-freezing sulfonated lignin (SL)-containing polyacrylic acid (PAA) (SL-g-PAA-Ni) hydrogel, with a high concentration of NiCl2. Ni2+ contributes multi-functions to the preparation of the hydrogel and its final properties, such as fast polymerization reaction as a result of the presence of redox pairs of Ni3+/Ni2+ and hydroquinone/quinone, and anti-freezing properties of the hydrogel due to the salt effects of NiCl2 so that at −20 °C the hydrogel shows similar properties to those at the room temperature. Thanks to the effective coordinations of Ni2+ with catecholic groups and carboxylic groups, as well as the rich hydrogen bonding capacity, the resultant hydrogel possesses excellent mechanical properties. High ionic conductivity (6.85 S·m−1) of the hydrogel is obtained due to the supply of high concentration of Ni2+. Moreover, the ionic solvation effect of NiCl2 in the hydrogel imparts excellent water retention ability, with water retention of ~93 % after 21-day storage. The SL-g-PAA-Ni hydrogel can accurately detect various human motions at −20 °C. The supercapacitor assembled from SL-g-PAA-Al hydrogel at −20 °C manifests a high specific capacitance of 252 F·g−1, with maximum energy density of 26.97 Wh·kg−1, power density of 2667 W·kg−1, and capacitance retention of 96.7 % after 3000 consecutive charge-discharge cycles.

Effects of short-term exposure to the heavy metal, nickel chloride (Nicl2) on gill histology and osmoregulation components of the gray mullet, Mugil cephalus

The gray mullet, Mugil cephalus is an inshore and bottom-feeding fish species of Oman sea. Therefore, the gray mullet may be more exposed to heavy metal contamination, as the toxic impacts of heavy metals mullet has been reported in various studies. This study was conducted to evaluate the toxic effects of the heavy metal, nickel (as NiCl2) on osmoregulation of the gray mullet by measuring blood biochemicals, hormones, minerals and gill histology. Fish (10 fish/tank) were experimentally exposed to NiCl2 at three environmentally relevant concentrations of 5, 10 and 15 μg/l for 96 h. Then, fish were challenged with seawater (35 mg/l) for a period of 120 min. The samples (blood and gill tissue) were collected After 96 exposure to NiCl2 and during salinity challenge (30, 60 and 120 min post challenge). The plasma levels of cortisol and glucose significantly increased in NiCl2−exposed fish. In addition, cortisol increased in all experimental groups 30 min after salinity challenge and then returned gradually to the same levels as the control at 120 min post salinity challenge (PSC). The triiodothyronine (T3) and thyroxine (T4) levels significantly decreased in response to 10 and 15 μg/l NiCl2. In all groups, the thyroid hormones significantly elevated at 30 min PSC. After 30 min PSC, T3 levels in all NiCl2−exposed fish and T4 in the treatment, 10 μg/l NiCl2 remained unchanged throughout the salinity challenge. In the treatment, 5 μg/l NiCl2, T4 levels were recovered at 120 min PSC and reached the same levels as the control. Exposure of fish to high concentrations of NiCl2 and salinity stress increased the lactate levels. However, lactate levels in 5 and 10 μg/l NiCl2 groups were recovered at 120 min PSC and reached the same levels as the control. Furthermore, plasma protein increased in response to 10 and 15 μg/l NiCl2. At 30 PSC, the protein levels decreased in control and 5 μg/l NiCl2 group, while it remained unchanged in fish exposed to 10 and 15 μg/l NiCl2 throughout the salinity challenge. Exposure of fish to NiCl2 disrupted the electrolyte (Na+, Cl−) balance both before and after salinity challenge, which may be due to gill lesions induced by the heavy metal and following alternations in gill permeability. However, fish in 5 μg/l NiCl2 re-established the ionic balance in the blood at the end of salinity challenge period. The malondialdehyde (MDA) levels significantly increased in response to 10 and 15 μg/l NiCl2. The MDA levels returned to the same levels as the control group at 120 min PSC. The results of the present study showed that nickel-induced toxicity (especially at high concentrations) can reduce the osmoregulation capabilities of mullet. However, fish are able to recover from the toxic effects over time, if contamination be eliminated.

Involvement of Ca2+ and ROS signals in nickel-impaired human sperm function

As one of the main environmental pollutants and occupational hazards, nickel has been reported to have mutagenic, carcinogenic, and teratogenic properties, as well as reproductive toxicity. However, how nickel affects human reproduction is still unclear. In this study, the toxicity of nickel on human sperm and the underlying mechanisms were evaluated in vitro. We found that NiCl2 (10, 50, and 250 μM) impaired sperm total motility and progressive motility in a dose- and time-dependent manner. In addition, sperm hyperactivation and the ability of human sperm to penetrate a viscous medium were found to be compromised after nickel exposure. Mechanically, NiCl2 significantly inhibited the basal intracellular Ca2+ signaling. Besides, reactive oxygen species (ROS), superoxide, and malondialdehyde levels were increased in human sperm after exposure to different concentrations of NiCl2. Consistently, eliminating excess ROS by N-acetyl-L-cysteine or tocopherol significantly alleviated nickel-impaired sperm motility. Taken together, these results revealed that nickel could compromise sperm functions by interfering with Ca2+ signaling and inducing excessive oxidative stress. These findings suggest that, in the high and occupational nickel exposure environments, the contribution of nickel toxicity to the males who wish to preserve their fertility is worthy of careful evaluation.

Mechanism of Dy3+ and Nd3+ Ions Electrochemical Coreduction with Ni2+, Co2+, and Fe3+ Ions in Chloride Melts

The present paper is devoted to the study of the processes of the mechanism of electrochemical coreduction of Dy3+ and Nd3+ ions with Ni2+, Co2+, and Fe3+ ions in the equimolar NaCl-KCl melt at 973 K and characterization of the synthesized samples. The performed voltammetry analysis of the electrochemical coreduction processes elucidated a significant difference in the values of the extraction potentials of the studied metals. This melt testifies that intermetallic compounds of Dy and Nd with Ni, Co, and Fe may be synthesized in the kinetic regime. The intermetallic phases of Dy and Nd with Ni, Co, and Fe are found to be formed along with the phases of metallic Ni, Co, and Fe either during electrolysis at the cathode current densities exceeding the limiting diffusion current of Ni2+, Co2+, and Fe3+ ions or in the potentiostatic regime at the potentials of the corresponding voltammetry curves. Therefore, the following interrelated key parameters affecting the electrochemical synthesis of Dy and Nd intermetallic compounds with Ni, Co, and Fe were determined: (i) composition of the electrolyte, i.e., concentrations of FeCl3, CoCl2, NiCl2, DyCl3, and NdCl3; (ii) cathode current density or electrolysis potential and (iii) electrolysis time. The obtained samples were characterized by micro-X-ray diffraction analysis, cyclic voltammetry, and scanning electron microscopy methods.

Self‐Healing and Flexible Porous Nickel/Polyurethane Composite Based on Multihealing Systems and Applications

AbstractWith the development of science and technology, the need for high performance sensors is more and more urgent to deal with different needs and environments. In this study, a flexible strain sensor with performance of self‐healing is developed based on porous nickel as conductive filler and polyurethane (PU) with hydrogen bonding, disulfide bond, and metal coordination bond as polymer matrix. Porous nickel is prepared by a new biotemplates method, and the effects of reaction temperature and concentration of NiCl2·6H2O on the morphology of porous nickel are studied. Polyurethanes containing hydrogen bonding, disulfide bonds, and metal coordination bonds are prepared, and the mechanical properties and self‐healing properties of polyurethanes with different contents of hard and soft segments are studied. A strain sensor is prepared by mixing porous nickel and polyurethane. The effect of filler content on mechanical properties, self‐healing properties, and electrical self‐healing properties is studied. The sensor is attached to the joints of human limbs, and the peak diagram of time‐relative resistance changes is obtained through the cyclic and repeated movements of the limbs. The sensor has excellent sensitivity.

Electrical and Structural Characterization of Polyaniline Synthesized in Acid Medium Having Nickel Salts as Impurities

Electrical properties of polyaniline (PANI) synthesized in a solution containing nickel salts are investigated. The structural characterization by scanning electron microscopy shows that PANI yielded in nickel chloride (NiCl2) has thicker structures with high porosity that increases insofar NiCl2 concentration does. The pH variation monitoring due to the nickel salt inclusion in solution shows that mass and thickness are strongly dependent on pH variation. Thermogravimetric investigation reveals that PANI formed in the presence of nickel salts is thermally more stable. This fact is more accentuated in samples produced in nickel nitrate and, also, produces the absorbance peak shift of some functional groups, as well as their intensification, as pointed by the infrared spectroscopy analysis. On the other side, the electrical characterization through the current–potential analysis shows that PANI conductivity is larger in PANI yielded in the presence of sulfates and lower in nitrates, while the impedance electrochemical analysis evidences the formation of a surface passivated PANI region having higher resistance and lower capacitance than PANI in bulk. Concerning the resistance of this region, the difference between surface and bulk PANI is smaller in the sample yielded in NiCl2, but the difference in capacitance is greater.

Hydrothermal facile fabrication of superhydrophobic magnetic nanospiky nickel wires: Optimization via statistical design

In the present research, novel superhydrophobic magnetic nanospiky nickel wires via a controlled one-step hydrothermal method were fabricated using Taguchi L16 statistical design. The effects of independent factors including concentration of NiCl2 .6H2O (50-125 mM), the concentration of N2H4.H2O (450-1650 mM), reaction temperature (80-100 ºC), and reaction time (6-12 h) on the wettability properties of octadecyl trichlorosilane (ODTS)-modified samples were investigated. Based on ANOVA and the main effect analyses, despite all factors affecting the wettability response, hydrazine solution concentration with a contribution percent of 47.22% had the most significant effect on the samples' hydrophobicity and growth mechanism as a reducing agent and bridging bidentate ligand. Under the predicted optimum conditions (A1¯,B3¯,C2¯,D2¯), the water contact angle (WCA) and contact angle hysteresis (CAH) were 162.78°±2.4º and 4.32°±0.9º, respectively. Morphological aspects and chemical composition of the as-prepared samples were studied using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive X-ray spectroscopy (EDX), and Vibrating Sample Magnetometer (VSM) analyses. According to the FESEM images, the length and spike diameters were ranged 500-800 nm and 50-90 nm, respectively. The conical nanospikes' growth on the nickel wires was not dependent on the external magnetic field. It just promoted the formation of straight wires along the present magnetic field. The coercivity (Hc) and remnant magnetism (Mr) in the presence of the magnetic field were 103.077 Oe and 7.80 emu/g, respectively, due to the crystallite arrangement anisotropy.

Quantitative anatomy mimicking slice phantoms.

To present a reproducible methodology for building an anatomy mimicking phantom with targeted T1 and T2 contrast for use in quantitative magnetic resonance imaging. We propose a reproducible method for creating high-resolution, quantitative slice phantoms. The phantoms are created using gels with different concentrations of NiCl2 and MnCl2 to achieve targeted T1 and T2 values. We describe a calibration method for accurately targeting anatomically realistic relaxation pairs. In addition, we developed a method of fabricating slice phantoms by extruding 3D printed walls on acrylic sheets. These procedures are combined to create a physical analog of the Brainweb digital phantom. With our method, we are able to target specific T1 /T2 values with less than 10% error. Additionally, our slice phantoms look realistic since their geometries are derived from anatomical data. Standardized and accurate tools for validating new techniques across sequences, platforms, and different imaging sites are important. Anatomy mimicking, multi-contrast phantoms designed with our procedures could be used for evaluating, testing, and verifying model-based methods.

In vitro assessment of the impact of nickel on the viability and steroidogenesis in the human adrenocortical carcinoma (NCI-H295R) cell line.

Nickel is a ubiquitous environmental pollutant, which has various effects on reproductive endocrinology. In this study, human adrenocortical carcinoma (NCI-H295R) cell line was used as an in vitro biological model to study the effect of nickel chloride (NiCl2) on the viability and steroidogenesis. The cells were exposed to different concentrations (3.90; 7.80; 15.60; 31.20; 62.50; 125; 250 and 500 microM) of NiCl2 and compared with control group (culture medium without NiCl2). The cell viability was measured by the metabolic activity assay. Production of sexual steroid hormones was quantified by enzyme linked immunosorbent assay. Following 48 h culture of the cells in the presence of NiCl2 a dose-dependent depletion of progesterone release was observed even at the lower concentrations. In fact, lower levels of progesterone were detected in groups with higher doses (>/=125 microM) of NiCl2 (P<0.01), which also elicited cytotoxic action. A more prominent decrease in testosterone production (P<0.01) was also noted in comparison to that of progesterone. On the other hand, the release of 17beta-estradiol was substantially increased at low concentrations (3.90 to 62.50 microM) of NiCl2. The cell viability remained relatively unaltered up to 125 microM (P>0.05) and slightly decreased from 250 microM of NiCl2 (P<0.05). Our results indicate endocrine disruptive effect of NiCl2 on the release of progesterone and testosterone in the NCI-H295R cell line. Although no detrimental effect of NiCl2 (</=62.50 microM) could be found on 17beta-estradiol production, its toxicity may reflect at other points of the steroidogenic pathway.

Determination of ED50 in a Calcareous Soil Contaminated with Different Concentrations of Ni

Background and Objectives: Soil microbial properties such as biomass, microbial respiration and nitrogen mineralization can be used as indicators to show the stress caused by heavy metal pollution on soil quality. The aim of this study was the measurement soil microbial activity to evaluate the effect of soil Ni contamination on soil quality and determination of ecological dose 50 (ED50). Method: This study was conducted as a factorial experiment in year 2016 based on a randomized completely design with three replications. The experiment factors including Ni concentration in six levels (0, 50, 100, 150, 300 and 600 mg Ni kg-1) and two incubation times (15 and 60 days). Soils sample was spiked uniformly with different concentrations of NiCl2. Microbial respiration, microbial biomass carbon, heterotrophic population and metabolic quotient were measured after incubation times of 15 and 60 days, then according to the results, ED50 was determined by using the dose-response curve. Findings: Soil Nickel contamination on the indicator was significantly effective at P<0.01 level. Heterotrophic population, respiration and microbial carbon biomass decreased significantly (P<0.01) compared to control by increasing the Ni concentration and incubation times, whereas the increase of Ni concentration and incubation times were not significantly affected on metabolic quotient. The minimum amount of microbial respiration, microbial biomass carbon, and the heterotrophic population was observed at the end of incubation times and 600 mg Ni kg-1 with 77.07, 75.72 and 99.99% decrement compared to the control, respectively. ED50 value (mg/kg soil) of microbial respiration, microbial biomass carbon, and heterotroph population increased from 77.55, 78.63, 81.34 to 97.84, 111.04 and 84.67 respectively, with increased incubation time. Discussion and Conclusion: The soil contaminated with Nickel acutely decreased the biological activity of soil and the ecological dose increased with increasing the incubation time, suggesting that toxicity of Ni to soil microbial activity was decreased with increased incubation time. Ni concentration of 100 mgNikg-1 soil can be considered as the critical range of Ni for soil quality at which negative effect was observed.

Design and evaluation of quantitative MRI phantoms to mimic the simultaneous presence of fat, iron, and fibrosis in the liver.

To design, construct, and evaluate quantitative MR phantoms that mimic MRI signals from the liver with simultaneous control of three parameters: proton-density fat fraction (PDFF), , and T1 . These parameters are established biomarkers of hepatic steatosis, iron overload, and fibrosis/inflammation, respectively, which can occur simultaneously in the liver. Phantoms including multiple vials were constructed. Peanut oil was used to modulate PDFF, MnCl2 and iron microspheres were used to modulate , and NiCl2 was used to modulate the T1 of water (T1,water ). Phantoms were evaluated at both 1.5 T and 3 T using stimulated-echo acquisition-mode MRS and chemical shift-encoded MRI. Stimulated-echo acquisition-mode MRS data were processed to estimate T1,water , T1,fat , , and for each vial. Chemical shift-encoded MRI data were processed to generate PDFF and maps, and measurements were obtained in each vial. Measurements were evaluated using linear regression and Bland-Altman analysis. High-quality PDFF and maps were obtained with homogeneous values throughout each vial. High correlation was observed between imaging PDFF with target PDFF (slope = 0.94-0.97, R2 = 0.994-0.997) and imaging with target (slope = 0.84-0.88, R2 = 0.935-0.943) at both 1.5 T and 3 T. The values of and were highly correlated with slope close to 1.0 at both 1.5 T (slope = 0.90, R2 = 0.988) and 3 T (slope = 0.99, R2 = 0.959), similar to the behavior observed in vivo. The value of T1,water (500-1200 ms) was controlled with varying NiCl2 concentration, while T1,fat (300 ms) was independent of NiCl2 concentration. Novel quantitative MRI phantoms that mimic the simultaneous presence of fat, iron, and fibrosis in the liver were successfully developed and validated.

Rapid multicontrast brain imaging on a 0.35T MR-linac.

Magnetic resonance-guided radiation therapy (MRgRT) has shown great promise for localization and real-time tumor monitoring. However, to date, quantitative imaging has been limited for low field MRgRT. This work benchmarks quantitative T1, R2*, and Proton Density (PD)mapping in a phantom on a 0.35T MR-linac and implements a novel acquisition method, STrategically Acquired Gradient Echo (STAGE). To further validate STAGE in a clinical setting, a pilot study was undertaken in a cohort of brain tumor patients to elucidate opportunities for longitudinal functional imaging with an MR-linac in the brain. STAGE (two triple-echo gradient echo (GRE) acquisitions) was optimized for a 0.35T low-field MR-linac. Simulations were performed to choose two flip angles to optimize signal-to-noise ratio (SNR) and T1-mapping precision. Tradeoffs between SNR, scan time, and spatial resolution for whole-brain coverage were evaluated in healthy volunteers. Data were inputted into a STAGE processing pipeline to yield four qualitative images (T1-weighted, enhanced T1-weighted, proton-density (PD) weighted, and simulated FLuid-Attenuated Inversion Recovery (sFLAIR)), and three quantitative datasets (T1, PD, and R2*). A benchmarking ISMRM/NIST phantom consisting of vials with variable NiCl2 and MnCl2 concentrations was scanned using variable flip angles (VFA) (2-60degrees) and inversion recovery (IR) methods at 0.35T. STAGE and VFA T1 values of vials were compared to IR T1 values. As measures of agreement with reference values and repeatability, relative error (RE) and coefficient of variability (CV) were calculated, respectively, for quantitative MR values within the phantom vials (spheres). To demonstrate feasibility, longitudinal STAGE data (pretreatment, weekly, and~2months post-treatment) were acquired in an IRB-approved pilot study of brain tumor cases via the generation of temporal and differential quantitative MRI maps. In the phantom, RE of measured VFA T1 and STAGE relative to IR reference values were 7.0±2.5% and 9.5±2.2% respectively. RE for the PD vials was 8.1±6.8% and CV for phantom R2* measurements was 10.1±9.9%. Simulations and volunteer experiments yielded final STAGE parameters of FA=50°/10°, 1×1×3mm3 resolution, TR=40ms, TE=5/20/34ms in 10min (64 slices). In the pilot study of brain tumor patients, differential maps for R2* and T1 maps were sensitive to local tumor changes and appeared similar to 3T follow-up MRI datasets. Quantitative T1, R2*, and PD mapping are promising at 0.35T agreeing well with reference data. STAGE phantom data offer quantitative representations comparable to traditional methods in a fraction of the acquisition time. Initial feasibility of implementing STAGE at 0.35T in a patient brain tumor cohort suggests that detectable changes can be observed over time. With confirmation in a larger cohort, results may be implemented to identify areas of recurrence and facilitate adaptive radiation therapy.

Synthesis and characterization of polyaniline-nickel chloride composites

NiCl2/polyaniline composites with varying NiCl2 concentration have been synthesized and characterized for structural and optical modifications in polyaniline with the addition of NiCl2, and to explore the effect of addition of NiCl2 on the electrical properties of polyaniline. FTIR spectral peaks attributed to various entities present in polyaniline have been shifted towards longer wavelengths with the addition of NiCl2. The d-spacing for the two x-ray diffraction peaks at 20.30° and 26.22° has been determined by using the Bragg’s relation and found to decrease with the addition of NiCl2. The SEM images of the composites indicate the uniform dispersal of the salt in the polymeric conformation. The band edge of UV-VIS spectra of the composites has been found to blue shift indicating increase in the band gaps with the increased NiCl2 concentration except for a concentration of 5%. The capacitance has been found to decrease with increase in frequency and the increase in the NiCl2 content. The resistance has been found to increase with the addition of NiCl2 thus establishing a positive correlation between the optical band gap and variations of resistance with the addition of NiCl2 to the polyaniline.

Nickel sulphide-reduced graphene oxide composites as counter electrode for dye-sensitized solar cells: Influence of nickel chloride concentration

Nickel sulphide-reduced graphene oxide (NiS-rGO) composite films have been prepared via modified Hummers’s method assisted with spin coating technique. The NiS-rGO samples were then employed as counter electrode in a dye-sensitized solar cell (DSSC). The main aim of this work is to investigate the relationship between the concentrations of NiCl2 with the properties of NiS-rGO and performance parameters of the device. The dominant rGO and minor NiS phase exist in the composite. The morphology of the composite is white strips rGO and NiS agglomerate particle. The element of C, O, Ni and S present in the composite. The highest η of 1.04% and Jsc of 7.39 mA cm−2 were obtained from the device with 0.06 M NiCl2 resulted from the longest carrier lifetime. The photovoltaic parameters results reveal that NiS-rGO composite has potential to become as a free platinum counter electrode of DSSC.