Material design of promising rare-earth free permanent magnet requires tailoring and controlling the intrinsic magnetic properties namely large saturation magnetization
, giant uniaxial magnetic ...anisotropy
, and high Curie temperature
. Based on first-principles electronic structure calculations, we present a detailed analysis for the intrinsic magnetic properties of Co
Fe
Ni and Co
Fe
NiN
ordered structures. We predict an enhanced structural stability with improved
ranging from 1.53-2.29 MJ m
for Co
Fe
NiN
ordered structures, with the exception of CoNiN
having planar anisotropy. Detailed analysis of the predicted large
, based on perturbation theory and electronic structure calculations, is attributed to the cumulative effect of contribution from the increased tetragonal distortion and induced orbital distortion from the simultaneous Co substitution and interstitial N-doping. By tailoring the
, we may create efficient and affordable PMs, bridging the gap between commonly used ferrite and high-performance Nd-Fe-B magnets.
Adsorption of arsenic onto iron-based adsorption media has been established as a convenient method for the removal of arsenic from contaminated water. The study describes the efficiency of iron oxide ...coated hollow poly(methyl methacrylate) microspheres (FHM) as an adsorptive media for the removal of arsenic from water. Hollow poly(methyl methacrylate) microspheres (HPMM) were synthesized by solvent evaporation and an electroless plating technique and the surface of the polymer was coated with iron oxide (FeO) particles. Structural characterization was performed using Optical Microscopy (OM), Scanning Electron Microscopy (SEM), Fourier Transform Infrared spectroscopy (FTIR), Energy Dispersive X-ray diffraction (EDAX), and Thermogravimetric Analysis (TGA). A study on the effect of the varying initial concentration of arsenic ions on percentage removal was performed in the laboratory and the adsorption capacity of the adsorbent was measured. Adsorption isotherm studies were carried out to evaluate the adsorption efficiency of FHM in removing arsenic from contaminated water. The Langmuir and Freundlich isotherm models were used to analyze the equilibrium experimental data. The isotherm study revealed that Langmuir adsorption data are well fitted and the maximum adsorption capacity of FHM in removing arsenic is 10.031 mg g
−1
. This high arsenic uptake capability combined with a low density of FHM makes it a potential material for arsenic removal particularly during the fabrication of lightweight portable water purification devices.
Adsorption of arsenic onto iron-based adsorption media has been established as a convenient method for the removal of arsenic from contaminated water.
We have synthesized diluted magnetic semiconducting nanoparticles of undoped and Ni doped ZnS, by varying Ni concentration, via chemical co-precipitation technique. The formation of cubic zinc blend ...structure and the incorporation of Ni into ZnS lattice are confirmed by the X-ray diffraction (XRD) measurements. Rietveld refinement of the structural parameters shows a reasonable GOF value. Transmission electron microscopy result reveals the crystalline nature of the ZnS nanocrystal with an average d-spacing of 3.1 Å and also clarifies that the average particle size of the nanoparticles is in the range of 3–7 nm, which are consistence with the XRD results. UV–visible measurement depicts that the band gap of the Ni doped ZnS nanoparticles is higher than that of bulk ZnS, which is a result of the quantum confinement effect. Room temperature photoluminescence (PL) spectra shows the green emission in Ni doped ZnS nanoparticles, which is the characteristic
3
T
2
–
3
A
2
transition of Ni
2+
ion and also depicts the PL quenching effect at higher Ni concentration. Fourier transform infrared measurements show different stretching and vibrational modes and also show the resonance interactions of the sulphide ions. Raman analysis reveals different phonon modes of ZnS and confirms the defect states. Room temperature magnetic measurements demonstrate the ferromagnetic behavior in undoped ZnS nanoparticles due to the presence of structural defects. Systemic studies on the magnetic properties revels that all the doped ZnS nanoparticles exhibit the carrier mediated ferromagnetism and the saturation magnetization increases with increasing concentration of Ni.
Abstract
An interfacial integration at the nanoscale domain through a core@shell (CS) nanostructure has constructively unbarred a wide dimension to researchers on biomedical applications, especially ...for magnetic fluid hyperthermia. Lately, the interconnection of the exchange bias effect (EBE) through the interface coupling to the magnetic heating efficiency has uttered its utmost prominence for researchers. Here, we delineate the ascendency of the heating ability through a coalescing assembly of mixed ferrite Co
0.5
Zn
0.5
Fe
2
O
4
(CZ) and soft magnetic material Fe
3
O
4
(F), by devising a network of CoZnFe
2
O
4
@Fe
3
O
4
(CZF) CS nanostructure. A hefty interface activity with validation of the EBE phenomenon is divulged through magnetic scrutiny for the CS sample. The magnetic nanoparticles heating response to applied magnetic field and frequency is discerned at three distinct fields, where the outcome prevailed to inflated specific loss power for CS CZF in distinction to bare F and CZ samples for all the assessments. Remarkably; a lofty intrinsic loss parameter is also perceived for the CS sample recorded to about 5.36 nHm
2
g
−1
; which is another eccentric outcome that significantly labels the CS CZF sample as a potentially high heating competence agent. This comprehension accords to a finer perspective to meliorate the theranostic environment for hyperthermia applications.
Systematic experimental and theoretical calculations have been performed to investigate the origin of the carrier-induced ferromagnetism in the Co-doped ZnS-diluted magnetic semiconductors. The ...crystalline structure, morphology of the chemically synthesized Co-doped ZnS nanoparticles are evaluated using X-ray diffraction (XRD) and transmission electron microscopy (TEM) and obtained the average crystallite size in the range 5–8 nm. Fourier transform-infrared spectra reveal the characteristic Zn–S vibrations of cubic ZnS and also show the splitting of peaks with increasing Co concentration which indicates that the Co-doping level beyond 3% affects the structure of ZnS. The room temperature ferromagnetic behavior analyzed by
M
–
H
curve exhibited up to the doping level 5%, achieving due to the indirect ‘
p
–
d
’ exchange interactions between the localized ‘
d
’ spins of Co
2+
ion and the free-delocalized carriers in the host lattice. The existence of the antiferromagnetic coupling is discernable beyond the 5% doping level, owing to the short-range super-exchange interactions between the characteristic ‘
d
’ spins of the Co
2+
ions which minimize the ferromagnetic ordering. Band structure and density of states (DOS) calculations demonstrate the
p
–
d
hybridization mechanism in Co-doped ZnS system which is the main cause of realizing ferromagnetic ordering in the system and also shows the half-metallic characteristics with the combination of semiconducting and metallic nature in the spin-up and spin-down states, respectively.
Manganese doped Zinc ferrite (Mn-ZnFe2O4, where Mn = 0%, 3%, 5% and 7%) nanoparticles were synthesized by a simple co-precipitation method. CTAB (cetyltrimethylammonium bromide) was used as a ...surfactant to inhibitgrowth and agglomeration. In this work, we have discussed on the influence of CTAB and Mn doping in tailoring the structural and magnetic properties of Mn-ZnFe2O4 nanoparticles for the effective application of magnetic hyperthermia. X-ray diffraction (XRD) pattern confirmed the formation of cubic spinel structure of Mn-ZnFe2O4 nanoparticles. Lattice parameter and x-ray densities were obtained from the Rietveld refinement of the XRD pattern. The presence of CTAB as a stabilizing layer adsorbed on the surface of the nanoparticles were confirmed by transmission electron microscope (TEM) and Raman vibrational spectrum. The saturation magnetization showsan increasing trend with Mn addition owing to cationic re-distribution and an increase super-exchange interaction between the two sub-lattices. Superparamagnetic behaviorof Mn-ZnFe2O4 nanoparticles were confirmed by temperature-dependent zero-field-cooling (ZFC) and field-cooling (FC) magnetization curves. The efficiency of induction heating measured by its specific absorption rate (SAR) and intrinsic loss power (ILP) value varies as a function of saturation magnetization. It has been hypothesized that the maximum generation of heat arises from Neel relaxation mechanism. The optimum generation of heat of Mn-ZnFe2O4 nanoparticle is determined by the higher frequency (f = 337 kHz) range and maximum concentration of Mn doping.
Objective We sought to characterize the impact of uterine leiomyomas (fibroids) in a racially diverse sample of women in the United States. Study Design A total of 968 women (573 white, 268 African ...American, 127 other races) aged 29-59 years with self-reported symptomatic uterine leiomyomas participated in a national survey. We assessed diagnosis, information seeking, attitudes about fertility, impact on work, and treatment preferences. Frequencies and percentages were summarized. The χ2 test was used to compare age groups. Results Women waited an average of 3.6 years before seeking treatment for leiomyomas, and 41% saw ≥2 health care providers for diagnosis. Almost a third of employed respondents (28%) reported missing work due to leiomyoma symptoms, and 24% believed that their symptoms prevented them from reaching their career potential. Women expressed desire for treatments that do not involve invasive surgery (79%), preserve the uterus (51%), and preserve fertility (43% of women aged <40 years). Conclusion Uterine leiomyomas cause significant morbidity. When considering treatment, women are most concerned about surgical options, especially women aged <40 years who want to preserve fertility.
Given the enormous and rising global need for permanent magnet supply, even minor enhancements to the magnetic characteristics and economic viability of permanent magnet materials could result in ...significant energy and financial savings. In this work, the experimental conditions were optimized in order to produce barium hexaferrite (BaFe
12
O
19
) substituted with transition elements (Co and Mn) through chemical co-precipitation method. Powder X-ray Diffraction (XRD), Transmission Electron Microscope (TEM) and Fourier Transform Infra-red (FTIR) were used to reveal the structure, morphology and vibrational spectrum of the sample. The site preference for cobalt and manganese was estimated using Rietveld refinement of the XRD spectrum. It is obvious that Co and Mn occupied two crystallographic inequivalent sites, 4f
2
and 4f
1
respectively. Investigation of magnetic properties (VSM) at room temperature showed that as Co and Mn concentrations increase, saturation magnetization and retentivity increase, but coercivity decreases. At higher substitution concentrations, the behavior is the inverse. The possible reasons for these behaviors were discussed. The close correlation between site selection by the dopant and magnetic properties is also demonstrated.
To conduct comparative cost analysis of hospital care for critically ill patients with Limited English Proficiency (LEP) versus patients with English proficiency (controls).
We conducted a historical ...cohort study using propensity matching at Mayo Clinic Rochester, a quaternary care academic center. We included hospitalized patients who had at least one admission to ICU during a 10-year period between 1/1/2008-12/31/2017.
Due to substantial differences in baseline characteristics of the groups, propensity matching for the covariates age, sex, race, ethnicity, APACHE 3 score, and Charlson Comorbidity score was used, and we achieved the intended balance. The final cohort included 80,404 patients, 4,246 with LEP and 76,158 controls. Patients with LEP had higher costs during hospital admission to discharge, with a mean cost difference of $3861 (95% CI $822 to $6900, p = 0.013) and also higher costs during index ICU admission to hospital discharge, with a mean cost difference of $3166 (95% CI $231 to $6101, p = 0.035). A propensity matched cohort including only those that survived showed those with LEP had significantly greater mean costs for all outcomes. Sensitivity analysis revealed that international patients with LEP had significantly greater overall hospital costs of $9,240 than patients with LEP who resided in the US (95% CI $3341 to $15,140, p = 0.002).
This is the first study to demonstrate significantly higher costs for patients with LEP experiencing a critical illness. The causes for this may be increased healthcare utilization secondary to communication deficiencies that impede timely decision making about care.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
An interfacial coupling origin of the exchange bias effect (EBE) is a novel phenomenon due to its technological and fundamental importance. We have carefully synthesized an Fe
3
O
4
@NiO (FO@N) ...core@shell (CS) nanostructure using a co-precipitation method, and the CS nanostructure formation was evident from the HRTEM analysis. The magnetic measurement study endorses unique characteristics on the temperature-dependent EBE switching from negative to the positive axis under a fixed cooling field. To the best of our knowledge, this unique characteristic behavior at a fixed cooling field has not been reported, particularly for the ferro/ferrimagnetic@antiferromagnetic FiM@AFM CS nanostructure. The switching is attributed to a formation of ferromagnetic (negative) or antiferromagnetic (positive) coupling arrangement at the magnetically disordered interface of two materials.
An interfacial coupling origin of the exchange bias effect (EBE) is a novel phenomenon due to its technological and fundamental importance.
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