How Solid Surfaces Control Stability and Interactions of Supported Cationic CuI(dppf) Complexes─A Solid-State NMR Study.

Organometallic complexes are frequently deposited on solid surfaces, but little is known about how the resulting complex-solid interactions alter their properties. Here, a series of complexes of the type Cu(dppf)(Lx)+ (dppf = 1,1'-bis(diphenylphosphino)ferrocene, Lx = mono- and bidentate ligands) were synthesized, physisorbed, ion-exchanged, or covalently immobilized on solid surfaces and investigated by 31P MAS NMR spectroscopy. Complexes adsorbed on silica interacted weakly and were stable, while adsorption on acidic γ-Al2O3 resulted in slow complex decomposition. Ion exchange into mesoporous Na-[Al]SBA-15 resulted in magnetic inequivalence of 31P nuclei verified by 31P-31P RFDR and 1H-31P FSLG HETCOR. DFT calculations verified that a MeCN ligand dissociates upon ion exchange. Covalent immobilization via organic linkers as well as ion exchange with bidentate ligands both lead to rigidly bound complexes that cause broad 31P CSA tensors. We thus demonstrate how the interactions between complexes and functional surfaces determine and alter the stability of complexes. The applied Cu(dppf)(Lx)+ complex family members are identified as suitable solid-state NMR probes for investigating the influence of support surfaces on deposited inorganic complexes.

Posttraumatic epilepsy in critically ill children with traumatic brain injury.

PURPOSE: The aim of this study was to determine the clinical, laboratory, and radiological factors related with posttraumatic epilepsy (PTE). METHODS: The study is a multicenter descriptive cross-sectional cohort study. Children who followed up for TBI in the pediatric intensive care unit between 2014 and 2021 were included. Demographic data and clinical and radiological parameters were recorded from electronic case forms. All patients who were in the 6-month posttraumatic period were evaluated by a neurologist for PTE. RESULTS: Four hundred seventy-seven patients were included. The median age at the time of trauma was 66 (IQR 27-122) months, and 298 (62.5%) were male. Two hundred eighty (58.7%) patients had multiple traumas. The mortality rate was 11.7%. The mean duration of hospitalization, pediatric intensive care unit hospitalization and mechanical ventilation, Rotterdam score, PRISM III score, and GCS at admission were higher in patients with epilepsy (p < 0.05). The rate of epilepsy was higher in patients with severe TBI, cerebral edema on tomography and clinical findings of increased intracranial pressure, blood transfusion in the intensive care unit, multiple intracranial hemorrhages, and intubated patients (p < 0.05). In logistic regression analysis, the presence of intracranial hemorrhage in more than one compartment of the brain (OR 6.13, 95%CI 3.05-12.33) and the presence of seizures (OR 9.75, 95%CI 4.80-19.83) were independently significant in terms of the development of epilepsy (p < 0.001). CONCLUSIONS: In this multicenter cross-sectional study, intracranial hemorrhages in more than one compartment and clinical seizures during intensive care unit admission were found to be independent risk factors for PTE development in pediatric intensive care unit patients with TBI.

Influence of ZSM-5 Crystal Size on Methanol-to-Olefin (MTO) vs. Ethanol-to-Aromatics (ETA) Conversion.

Crystal size is a key parameter of zeolites applied as catalysts. Herein, ZSM-5 crystals with similar physicochemical and acid properties, few defects, and aluminum exclusively in tetrahedral coordination are synthesized and the influence of the crystal size on the MTO and ETA conversion is investigated. Short olefins are the main products of the MTO conversion, whereas larger olefins and aromatics dominate the products after ETA conversion. In the case of both feeds, an increased crystal size decreases the catalyst's lifetime. The MTO conversion over larger ZSM-5 altered the product distribution, which was not the case for the ETA conversion. The reason is that the instantly available aromatics during ETA conversion lead to fast coking and zeolite crystals only active in the outer layers. Thus, the different reactivity of different-sized ZSM-5 is direct proof of a different conversion mechanism for both alcohols.

The Effect of Altitude on Phenolic, Antioxidant and Fatty Acid Compositions of Some Turkish Hazelnut (Coryllus avellana L.) Cultivars.

Turkey is the leading producer and exporter of hazelnuts, producing approximately 64% of global hazelnut production. This research investigated the effects of cultivars and altitude on the phenolic, antioxidant, and fatty acid compositions of five hazelnut cultivars grown at three different altitudes, 100 m, 350 m, and 800 m, in Ordu province, one of the territories that produce the most hazelnuts. The results showed that the cultivar and location significantly affected phenolic compounds, antioxidant activity, and fatty acid (FA) content. The lowest (2.30 mg/kg-Yagli) and highest (21.11 mg/kg-Kara) gallic acids were obtained at 100 m. The highest total phenolic content and antioxidant activity were found in the nuts grown at 350 m in the Kara and Palaz cultivars, at 100 m in the Yagli and Sivri cultivars, and at 800 m in the Çakildak cultivar. Oleic acid was the predominant FA in the cultivars and possessed a diverse trend according to the altitude and cultivar, ranging from 76.04% to 84.80%, increasing with altitude in all cultivars except Çakildak. Palmitic acid was the predominant saturated FA followed by stearic acid, which significantly varied according to the elevations. This study suggests that the responses of hazelnuts to altitude depend on the cultivar; hence, a proper approach to producing nuts containing more phenolic, fatty acids, and antioxidant activity includes choosing a suitable cultivar for a specific elevation.

Interference of preservatives on urinary iodine measurement by Sandell-Kolthoff method.

This report aimed to determine the effects of different preservatives used to maintain the integrity of urine samples for a 24-hour urine collection on urinary iodine measurement by the Sandell-Kolthoff method in vitro. The selected preservatives were hydrochloric acid, acetic acid, boric acid, sodium carbonate, sodium fluoride, thymol with isopropanol, sodium chloride with formalin, and Saccomanno fixative. The test samples to which these preservatives were added and the control samples for basal measurements were prepared from the urine pool obtained from urine samples taken from healthy volunteers. The urinary iodine measurements were performed following the calculated minimum number of replicates in these prepared samples. The data analysis of the interferences of the preservatives was performed based on the Clinical and Laboratory Standards Institute EP7-A2 guideline. The preservatives that had more acceptable effects on the urinary iodine measurement compared to the others were sodium carbonate (0.5% w/v) and thymol (10% w/v) with isopropanol (0.25% v/v) for 24-hour storage at room temperature. This report presented reliable and usable data revealing the effects of preservatives, which are frequently used to maintain the integrity of urine samples for a 24-hour urine collection, on urinary iodine measurement. There are need to reveal the possible effects of potential exogenous interfering substances and the pathological levels of endogenous analytes or shaped elements in the urine matrix on methods with routine clinical use in making medical decisions.

Early Pacemaker Implantation after Transcatheter Aortic Valve Replacement: Impact of PlasmaBlade™ for Prevention of Device-Associated Bleeding Complications.

Background and Objectives: Permanent pacemaker implantation (PPI) is frequently required following transcatheter aortic valve replacement (TAVR). Dual antiplatelet therapy (DAPT) or oral anticoagulation therapy (OAK) is often necessary in these patients since they are at higher risk of thromboembolic events due to TAVR implantation, high incidence of coronary artery diseases (CAD) with the necessity of coronary intervention, and high rate of atrial fibrillation with the need of stroke prevention. We sought to evaluate the safety, efficiency, and clinical outcomes of early PPI following TAVR using the PlasmaBlade™ (Medtronic Inc., Minneapolis, MN, USA) pulsed electron avalanche knife (PEAK) for bleeding control in patients under DAPT or OAK. Materials and Methods: This retrospective single-center study included patients who underwent PPI after transfemoral TAVR (TF) at our center between December 2015 and May 2020. All PPI were performed using the PlasmaBlade™ Device. Results: The overall PPI rate was 14.1% (83 of 587 patients; 82.5 ± 4.6 years; 45.8% male). The PPI procedures were used to treat high-grade atrioventricular block (81.9%), severe sinus node dysfunction (13.3%), and alternating bundle branch block (4.8%). At the time of the procedure, 35 (42.2%) patients received DAPT, and 48 (57.8%) patients received OAK (50% with vitamin K antagonist (VKA) and 50% with novel oral anticoagulants (NOAK)). One device-pocket hematoma treated conservatively occurred in a patient (1.2%) receiving NOAK. Two re-operations were necessary in patients due to immediate lead dislocation (2.4%). Conclusions: The results of this study illustrate that the use of PlasmaBlade™ for PPI in patients after a TAVR who require antithrombotic treatment is feasible and might result into lower rates of severe bleeding complications compared to rates reported in the literature. Use of the PlasmaBlade device may be considered in this specific group of patients because of their high risk of bleeding.

Impact of previous left atrial ablation procedures on the mechanism of left atrial flutter: A single-centre experience.

INTRODUCTION: Left atrial flutter predominantly occurs after surgical or ablation procedures but this entity has also been recently reported in individuals without previous interventions. The use of high-density electroanatomical mapping-systems (HDM) has improved the understanding of underlying mechanisms beyond entrainment maneuvers and substrate analyses. We aimed to evaluate the mechanism of left atrial (LA) flutters in preablated vs ablation-naïve individuals and sought to assess the efficacy of empiric ablations sets in these groups. METHODS AND RESULTS: We included 55 patients admitted for ablation of LA flutter between July 2017 and August 2019. On the basis of HDM analyses the arrhythmia mechanism was determined with consecutive ablation targeting the suspected critical isthmus. Mean age was 69.8 ± 10.7 years, with 26 of 55 (47.3%) male patients. Thirty-nine (71%) patients had previously undergone LA ablation. Arrhythmia mechanisms differed between preablated and ablation-naïve patients as anatomical structure-related LA flutters (perimitral, roof-dependent, within-pulmonary veins) were more frequent in the preablated cohort compared to ablation-naïve individuals (74.4% vs 43.8%; P = .03). In ablation-naïve patients, most flutters (9 of 16, 56.3%) were related to low-voltage areas at the anterior/posterior wall. Acute termination rates were high (>90%) in both groups. Empirical mitral isthmus or roof lines showed a potential higher success rate in preablated patients. CONCLUSION: We identified different mechanisms of LA flutters in preablated vs ablation-naïve patients. In ablation-naïve patients, most tachycardias involved low-voltage areas rather than anatomical structures. Using HDM, acute success rates were high. Hypothetical linear ablations were less successful in ablation-naïve individuals, further highlighting the need to identify the specific individual tachycardia mechanism in these patients.

Kinetic and in silico studies of hydroxy-based inhibitors of carbonic anhydrase isoforms I and II.

A series of hydroxy and phenolic compounds have been assayed for the inhibition of two physiologically relevant carbonic anhydrase (CA, EC 4.2.1.1) isozymes, the cytosolic human isozymes I and II. The investigated molecules showed inhibition constants in the range of 1.07-4003 and 0.09-31.5 µM at the hCA I and hCA II enzymes, respectively. In order to investigate the binding mechanisms of these inhibitors, in silico studies were also applied. Molecular docking scores of the studied compounds are compared using three different scoring algorithms, namely Glide/SP, Glide/XP and Glide/IFD. In addition, different ADME (absorption, distribution, metabolism and excretion) analysis was performed. All the examined compounds were found within the acceptable range of pharmacokinetic profiles.

Synthesis and determination of some biological activities of novel 2,4-dinitrophenyl derivatives.

The antioxidant and radical scavenging activities of the synthesized compounds 3, 5, and 6 were determined by various in vitro assays such as 2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid radical (ABTS(·+) ) scavenging, ferric ion (Fe(3+) ) reducing power and ferrous ion (Fe(2+) ) chelating activities. Moreover, these activities were compared to those of standard antioxidants such as butylated hydroxyanisole, butylated hydroxytoluene, and trolox. The results showed that the new compounds (3, 5, and 6) had potential antioxidant activity. Besides, inhibition of the two human cytosolic carbonic anhydrase (hCA, EC 4.2.1.1) isozymes I and II with some nitrobenzene compounds was investigated. Compounds 1-6 showed Ki values in the range of 4.88-193.4 µM and 5.295-54.75 µM for hCA I and hCA II, respectively.

Cu(dppf) complexes can be synthesized from Cu-exchanged solids and enable a quantification of the Cu-accessibility by 31P MAS NMR spectroscopy.

Herein, we apply three different copper-exchanged materials (Na-[Al]SBA-15, silica, Na-MCM-22) as hosts for a direct synthesis of CuI(1,1'-bis(diphenylphosphino)ferrocene = dppf) complexes in cationic ion exchange position. Using 31P MAS NMR spectroscopy, we show that identical complexes as after ion exchange are generated if the solids are applied as reactants directly. The homogeneity of copper exchanges is evaluated by EDX spectroscopy. Both CuI and CuII result in the formation of complexes, thereby oxidizing dppf. Cu-particles were not reactive. Optimized conditions for a maximized complex formation are identified applying quantitative 31P MAS NMR spectroscopy and ICP-OES. Only accessible copper in cationic position of the solids forms the complexes. This enables a quantification of the amount of copper in mesopores vs. the total copper amount. Thus, besides a new synthesis of the complex a suitable method for quantitative elucidation of the location of copper cations is demonstrated herein.

Development of bilayer tissue-engineered scaffolds: combination of 3D printing and electrospinning methodologies.

Although different fabrication methods and biomaterials are used in scaffold development, hydrogels and electrospun materials that provide the closest environment to the extracellular matrix have recently attracted considerable interest in tissue engineering applications. However, some of the limitations encountered in the application of these methods alone in scaffold fabrication have increased the tendency to use these methods together. In this study, a bilayer scaffold was developed using 3D-printed gelatin methacryloyl (GelMA) hydrogel containing ciprofloxacin (CIP) and electrospun polycaprolactone (PCL)-collagen (COL) patches. The bilayer scaffolds were characterized in terms of chemical, morphological, mechanical, swelling, and degradation properties; drug release, antibacterial properties, and cytocompatibility of the scaffolds were also studied. In conclusion, bilayer GelMA-CIP/PCL-COL scaffolds, which exhibit sufficient porosity, mechanical strength, and antibacterial properties and also support cell growth, are promising potential substitutes in tissue engineering applications.

Correction to "Design of Cinnamaldehyde- and Gentamicin-Loaded Double-Layer Corneal Nanofiber Patches with Antibiofilm and Antimicrobial Effects".

[This corrects the article DOI: 10.1021/acsomega.3c00914.].

Human performance in predicting enhancement quality of gliomas using gadolinium-free MRI sequences.

BACKGROUND AND PURPOSE: To develop and test a decision tree for predicting contrast enhancement quality and shape using precontrast magnetic resonance imaging (MRI) sequences in a large adult-type diffuse glioma cohort. METHODS: Preoperative MRI scans (development/optimization/test sets: n = 31/38/303, male = 17/22/189, mean age = 52/59/56.7 years, high-grade glioma = 22/33/249) were retrospectively evaluated, including pre- and postcontrast T1-weighted, T2-weighted, fluid-attenuated inversion recovery, and diffusion-weighted imaging sequences. Enhancement prediction decision tree (EPDT) was developed using development and optimization sets, incorporating four imaging features: necrosis, diffusion restriction, T2 inhomogeneity, and nonenhancing tumor margins. EPDT accuracy was assessed on a test set by three raters of variable experience. True enhancement features (gold standard) were evaluated using pre- and postcontrast T1-weighted images. Statistical analysis used confusion matrices, Cohen's/Fleiss' kappa, and Kendall's W. Significance threshold was p < .05. RESULTS: Raters 1, 2, and 3 achieved overall accuracies of .86 (95% confidence interval [CI]: .81-.90), .89 (95% CI: .85-.92), and .92 (95% CI: .89-.95), respectively, in predicting enhancement quality (marked, mild, or no enhancement). Regarding shape, defined as the thickness of enhancing margin (solid, rim, or no enhancement), accuracies were .84 (95% CI: .79-.88), .88 (95% CI: .84-.92), and .89 (95% CI: .85-.92). Intrarater intergroup agreement comparing predicted and true enhancement features consistently reached substantial levels (≥.68 [95% CI: .61-.75]). Interrater comparison showed at least moderate agreement (group: ≥.42 [95% CI: .36-.48], pairwise: ≥.61 [95% CI: .50-.72]). Among the imaging features in the EPDT, necrosis assessment displayed the highest intra- and interrater consistency (≥.80 [95% CI: .73-.88]). CONCLUSION: The proposed EPDT has high accuracy in predicting enhancement patterns of gliomas irrespective of rater experience.

Development of a Near-Zero-Waste Valorization Concept for Waste NdFeB Magnets: Production of Antimicrobial Fe Alginate Beads via Adsorption and Recovery of High-Purity Rare-Earth Elements.

Nowadays, with the evolution of technology, rare earths are raw materials for a multitude of products, especially in high technological applications. A high amount of REEs is used in the production of permanent magnets, particularly NdFeB. The demand for some of the REEs, including neodymium, praseodymium, and dysprosium, is expected to increase in the coming years. REEs are defined as critical materials due to their high supply risk and economic importance. Recycling secondary raw materials for supplying REEs in the future is one promising option, and one of the best candidates is NdFeB magnets. NdFeB magnets include approximately 30% REEs and 66% of iron. For the near-zero-waste concept, the recovered iron from NdFeB must be evaluated in other applications. In this study, the near-zero-waste valorization concept for EoL-NdFeB magnets is developed, and high-purity REEs are achieved with a two-step process, including leaching and adsorption using alginate beads. Moreover, antimicrobial Fe alginate beads are produced in the leach liquor via adsorption. The antimicrobial activity of the produced Fe alginate beads is evaluated with disc diffusion and broth dilution methods against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The most effective antibacterial Fe alginate beads are against E. coli and S. aureus with inhibitions of 87.21 and 56.25%, respectively.

Three-Dimensional-Printed GelMA-KerMA Composite Patches as an Innovative Platform for Potential Tissue Engineering of Tympanic Membrane Perforations.

Tympanic membrane (TM) perforations, primarily induced by middle ear infections, the introduction of foreign objects into the ear, and acoustic trauma, lead to hearing abnormalities and ear infections. We describe the design and fabrication of a novel composite patch containing photocrosslinkable gelatin methacryloyl (GelMA) and keratin methacryloyl (KerMA) hydrogels. GelMA-KerMA patches containing conical microneedles in their design were developed using the digital light processing (DLP) 3D printing approach. Following this, the patches were biofunctionalized by applying a coaxial coating with PVA nanoparticles loaded with gentamicin (GEN) and fibroblast growth factor (FGF-2) with the Electrohydrodynamic Atomization (EHDA) method. The developed nanoparticle-coated 3D-printed patches were evaluated in terms of their chemical, morphological, mechanical, swelling, and degradation behavior. In addition, the GEN and FGF-2 release profiles, antimicrobial properties, and biocompatibility of the patches were examined in vitro. The morphological assessment verified the successful fabrication and nanoparticle coating of the 3D-printed GelMA-KerMA patches. The outcomes of antibacterial tests demonstrated that GEN@PVA/GelMA-KerMA patches exhibited substantial antibacterial efficacy against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. Furthermore, cell culture studies revealed that GelMA-KerMA patches were biocompatible with human adipose-derived mesenchymal stem cells (hADMSC) and supported cell attachment and proliferation without any cytotoxicity. These findings indicated that biofunctional 3D-printed GelMA-KerMA patches have the potential to be a promising therapeutic approach for addressing TM perforations.

Surface immobilized Cu-1,10-phenanthroline complexes with α-aminophosphonate groups in the 5-position as heterogenous catalysts for efficient atom-transfer radical cyclizations.

Many Cu catalyzed ATRC reactions suffer from low catalyst activity and stability. We have synthesized five 1,10-phenanthroline ligands substituted in the 5-position with α-aminophosphonate groups, through which the corresponding Cu complexes can be immobilized on Al2O3. These catalysts show similar activity and higher selectivity than the homogenous catalysts while being recyclable.

Design of Cinnamaldehyde- and Gentamicin-Loaded Double-Layer Corneal Nanofiber Patches with Antibiofilm and Antimicrobial Effects.

In this study, two-layer poly(vinyl alcohol)/gelatin (PVA/GEL) nanofiber patches containing cinnamaldehyde (CA) in the first layer and gentamicin (GEN) in the second layer were produced by the electrospinning method. The morphology, chemical structures, and thermal temperatures of the produced pure (PVA/GEL), CA-loaded (PVA/GEL/CA), GEN-loaded (PVA/GEL/GEN), and combined drug-loaded (PVA/GEL/CA/GEN) nanofiber patches were determined by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and differential scanning calorimetry, respectively. Their mechanical properties, swelling and degradation behavior, and drug release kinetics were investigated. SEM images showed that both drug-free and drug-loaded nanofiber patches possess smooth and monodisperse structures, and nanofiber size increase occurred as the amount of drug increased. The tensile test results showed that the mechanical strength decreased as the drug was loaded. According to the drug release results, CA release ended at the 96th hour, while GEN release continued until the 264th hour. The antibacterial and antibiofilm activities of PVA/GEL, PVA/GEL/CA, PVA/GEL/GEN, and PVA/GEL/CA/GEN nanofiber patches against Pseudomonas aeruginosa and Staphylococcus aureus were evaluated. Results showed that PVA/GEL/GEN and PVA/GEL/CA/GEN nanofiber patches have excellent antibacterial and antibiofilm activities. Moreover, all materials were biocompatible, with no cytotoxic effects in the mammalian cell model for 8 days. PVA/GEL/GEN nanofiber patches were the most promising material for a high cell survival ratio, which was confirmed by SEM images. This research aims to develop an alternative method to stop and treat the rapid progression of bacterial keratitis.

Nd Recovery from Wastewater with Magnetic Calcium Alginate ((1,4)-ß-d-Mannuronic Acid and α-L-Guluronic Acid) Hydrogels.

In this study, a magnetic adsorbent material was produced, by environmentally friendly and inexpensive precursor materials, to clean wastewater that may result from primary and secondary rare earth metal (REM) production. Then, the absorption of Nd3+ ions from wastewater was done and this process's kinetic and isotherm models were developed. Thus, the removal of Nd3+ from wastewater with magnetic materials was accomplished, and then, this precious metal was recovered by using different acid media. First, Fe sub-micron particles were successfully produced by the polyol method. To increase the stability of Fe-based particles, their surfaces were covered with an oxide layer, and the average thickness was determined as 16 nm. The synthesized Fe particles were added into the calcium alginate beads and then coated with chitosan to increase the pH stability of the gels. The chemical composition of the gels was determined by Fourier transform infrared spectroscopy, the thermal properties were determined by differential scanning calorimetry, and the magnetic properties were determined by vibrating-sample magnetometer analysis. The magnetic saturation of the hydrogels was 0.297 emu/g. After the production of magnetic calcium alginate hydrogels, Nd3+ ion removal from wastewater was done. Wastewater was cleaned with 94.22% efficiency. The kinetic models of the adsorption study were derived, and isotherm studies were done. Adsorption reaction fitted different kinetic models at different time intervals and the Freundlich isotherm model. The effect of pH, temperature, and solid-liquid ratio on the system was determined and the thermodynamic constants of the system were calculated. After the adsorption studies, Nd3+ ions were regenerated in different acid environments and achieved an 87.48% efficiency value. The removal of Nd3+ ions from wastewater was carried out with high efficiency, the gels obtained as a result of adsorption were regenerated with high efficiency by using acid media, and it was predicted that the gels could be reused. This study is thought to have reference results not only for the removal of REM from wastewater by magnetic adsorption materials but also for the adsorption of heavy metals from wastewater.

An Overview of Advances in the Chromatography of Drugs Impurity Profiling.

A systematic literature survey published in several journals of pharmaceutical chemistry and of chromatography used to analyze impurities for most of the drugs that have been reviewed. This article covers the period from 2016 to 2020, in which almost of chromatographic techniques have been used for drug impurity analysis. These chromatography techniques are important in the analysis and description of drug impurities. Moreover, some recent developments in forced impurity profiling have been discussed, such as buffer solutions, mobile phase, columns, elution modes, and detectors are highlighted in drugs used for the study. This primarily focuses on thorough updating of different analytical methods which include hyphenated techniques for detecting and quantifying impurity and degradation levels in various pharmaceutical matrices.

Recycling of NdFeB magnets employing oxidation, selective leaching, and iron precipitation in an autoclave.

The increasing production of neodymium-iron-boron (NdFeB) magnets for technological applications results in disposal problems. NdFeB magnets contain a significant quantity of rare earth elements (REEs). China is the largest REEs producer, but it applies quotas and increases the export prices of REEs. To address this issue, this study aims at investigating the recovery process of REEs from scrap NdFeB magnets. After oxidation of NdFeB magnet powders, selective leaching with nitric acid was carried out to achieve high-purity REE-rich leaching liquor. First, the oxidation kinetics of NdFeB powders was studied in detail to determine the oxidation temperature and duration. Afterwards, the effects of selective leaching parameters, including acid concentration, leaching temperature, stirring speed and solid/liquid ratio, were examined by analysis of variance (ANOVA) analysis based on Taguchi method. The most substantial parameters were assigned to be the temperature and solid/liquid ratio. Eventually, the dissolution kinetics were studied to propose a model for REEs. Several universal equations for dissolution kinetics were tested, and (1 - (1 - x) = k × tn) gives the best results for REEs. The findings show that the leaching process follows the shrinking core model. Activation energy was calculated to be 40.375 kJ mol-1 for REEs. As the last step, the iron dissolved during leaching was precipitated as hematite in the autoclave. The hematite precipitation experiments were performed based on the Box-Behnken design. The effect of precipitation parameters was investigated by ANOVA analysis, and the precipitation process was optimized using response surface methodology (RSM), which resulted in the minimum iron and maximum REEs content in the leach liquor.