Mn1-xZnxFe2O4 (0 ≤ x ≤ 0.7) nanoparticles were synthesised by a hydrothermal process. X-ray diffraction patterns reveal that all samples have spinel crystalline structures. Scanning electron ...microscopy and X-ray diffraction patterns show that nanoparticles are near-spherical in morphology and their average size is 13–45 nm. The elemental analysis was carried out by energy dispersive X-ray analysis technique. The optical direct band gap of Mn1-xZnxFe2O4 nanoparticle decreases from 2.38 to 1.88 eV as the Zn content increases. Moreover, the saturation magnetisation at room temperature tends to decrease with increasing Zn content. The specific absorption rate (SAR) values were measured at a fixed frequency of 178 kHz with magnetic field amplitude of 80 Oe. The SAR initially decreases with the sample concentration and its decrease is attributed to the enhancement of dipolar interaction and agglomeration of the particles. The intrinsic loss power (ILP) value varies between 6.5 and 15 nHm2kg−1 in the biologically safe experimental limit of 1.13 × 109Am−1s−1. The high value of ILP makes these nanoparticles possible for potential candidates for treating magnetic hyperthermia.
•sGrain size decreases as the Zn2+ concentration increases.•FTIR, Raman and spectra used to characterize the samples..•The optical band gap were calculated using UV-Vis diffuses reflectance spectra.•Ms and TC values decreases dramatically when Zn2+ doping increases..•ILP value varies between 6.5−15 nHm2kg−1, indicating Mn-Zn ferrite NPs can be used for magnetic hyperthermia.
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Investigations of wave and vibration properties of single- or multi-walled carbon nanotubes based on nonlocal beam models have been reported recently. However, there are numerous inconsistencies in ...the handling of the governing equations, applied forces, and boundary conditions based on some of the reported nonlocal beam models. In this paper, the consistent equations of motion for the nonlocal Euler and Timoshenko beam models are provided, and some issues on the nonlocal beam theories are discussed. The models are then applied to the studies of wave properties of single- and double-walled nanotubes. The wave and vibration properties of the nanotubes based on the presented nonlocal beam equations are studied, and scale effects are discussed.
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We present a detailed report on sterile neutrino oscillation and 235Uν¯e energy spectrum measurement results from the PROSPECT experiment at the highly enriched High Flux Isotope Reactor (HFIR) at ...Oak Ridge National Laboratory. In 96 calendar days of data taken at an average baseline distance of 7.9 m from the center of the 85 MW HFIR core, the PROSPECT detector has observed more than 50,000 interactions of νe produced in beta decays of 235U fission products. New limits on the oscillation of ν¯e to light sterile neutrinos have been set by comparing the detected energy spectra of ten reactor-detector baselines between 6.7 and 9.2 meters. Measured differences in energy spectra between baselines show no statistically significant indication of ν¯e to sterile neutrino oscillation and disfavor the reactor antineutrino anomaly best-fit point at the 2.5σ confidence level. The reported 235U ν¯e energy spectrum measurement shows excellent agreement with energy spectrum models generated via conversion of the measured 235U beta spectrum, with a χ2/d.o.f. of 31/31. PROSPECT is able to disfavor at 2.4σ confidence level the hypothesis that 235U ν¯e are solely responsible for spectrum discrepancies between model and data obtained at commercial reactor cores. A data-model deviation in PROSPECT similar to that observed by commercial core experiments is preferred with respect to no observed deviation, at a 2.2σ confidence level.
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In light optics, beams with orbital angular momentum (OAM) can be produced by employing a properly-tuned two-cylinder-lens arrangement, also called π/2 mode converter. It is not possible to convey ...this concept directly to the beam in an electron microscope due to the non-existence of cylinder lenses in commercial transmission electron microscopes (TEMs). A viable work-around are readily-available electron optical elements in the form of quadrupole lenses. In a proof-of-principle experiment in 2012, it has been shown that a single quadrupole in combination with a Hilbert phase-plate produces a spatially-confined, transient vortex mode.
Here, an analogue to an optical π/2 mode converter is realized by repurposing a CEOS DCOR probe corrector in an aberration corrected TEM in a way that it resembles a dual cylinder lens using two quadrupoles. In order to verify the presence of OAM in the output beam, a fork dislocation grating is used as an OAM analyser. The possibility to use magnetic quadrupole fields instead of, e.g., prefabricated fork dislocation gratings to produce electron beams carrying OAM enhances the beam brightness by almost an order of magnitude and delivers switchable high-mode purity vortex beams without unwanted side-bands.
•Experimental realization of a π/2 mode converter that produces an electron vortex beam using a Hilbert phase plate and a dual quadrupole setup.•Verification of the orbital angular momentum (OAM) content using a binary holographic vortex mask as an OAM analyser.•Wave optical simulations further verified the OAM content and the high mode purity of >80%.•7.5-fold higher beam brightness compared to the holographic vortex mask technique.
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Deep-powder-bed additive manufacturing (AM) can lead to distinctive microstructural features. In this study, 300-mm long cylindrical rods (12-mm diameter) of Ti–6Al–4V were vertically built to the ...limit height of a commercial selective electron beam melting (SEBM) system for quantitative three-dimensional (3D) characterization of the defects by X-ray micro-computed tomography (μ-CT). Detailed μ-CT data from 18,337 consecutive slices revealed a strong dependence of defect characteristics on build height, including defect volume, population, sphericity, major axis length, depth and orientation angle. The first 100-mm build exhibited the worst presence of defects by each measurement, while the middle and last 100-mm builds contained much fewer defects, especially the last 100-mm build, which was free of lack-of-fusion defects (sphericity < 0.5). As a result, the first 100-mm build displayed 50% lower reduction of area and 20% lower strain-to-fracture than the last 100-mm build, while the tensile strengths varied within just ±3%. An outer 3-mm thick ring and a central 1.5-mm diameter region were found to contain substantially less defects along the 300-mm build height. The dependence of defect features on build height was attributed to the existence of an upward temperature gradient during SEBM. The 3D defect features revealed by μ-CT along the build height provide important implications for deep-powder-bed AM by SEBM.
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•Vitamin B12 is useful in treating diverse chronic pain conditions.•We performed a systematic literature review and meta-analysis of RCTs to evaluate the efficacy of vitamin B12 in the management of ...PHN.•Vitamin B12 administration significantly reduces the NRS score and improves the quality of life in PHN patients with moderate quality evidence.•Vitamin B12 supplementation also significantly decreases the number of patients using analgesics.•Vitamin B12 appears to be an attractive complementary therapy for PHN patients.
Postherpetic neuralgia (PHN) is the most distressful complication of herpes zoster. PHN results in an impaired quality of life and higher healthcare utilization. Vitamin B12 has been proven to be effective in pain relief for various conditions.
We conducted a systematic review and a meta-analysis to evaluate the efficacy of vitamin B12 supplementation in PHN patients.
PubMed, Embase, Cochrane Library, CINAHL, and ClinicalTrials.gov registry were searched. Randomised control trials evaluating the efficacy and safety of vitamin B12 in PHN patients were selected. Eligible trials were abstracted and assessed for the risk of bias by two reviewers, and the results of pain indicators in the selected trials were analysed.
Four trials including 383 participants were published between 2013 and 2016. Compared with the placebo group, the Vitamin B12 group exhibited a significant decrease in the Numeric Rating Scale score, with a mean difference of −4.01 (95% confidence interval = −4.70 to −3.33). Vitamin B12 administration improved the quality of life of PHN patients with moderate quality evidence and significantly decreased the number of patients using analgesics.
Vitamin B12 appears to be an attractive complementary therapy for PHN patients. Further investigation is needed before conclusive recommendations can be made.
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29.
Single-Molecule Enzymatic Dynamics Lu, H. Peter; Xun, Luying; Xie, X. Sunney
Science (American Association for the Advancement of Science),
12/1998, Volume:
282, Issue:
5395
Journal Article
Peer reviewed
Enzymatic turnovers of single cholesterol oxidase molecules were observed in real time by monitoring the emission from the enzyme's fluorescent active site, flavin adenine dinucleotide (FAD). ...Statistical analyses of single-molecule trajectories revealed a significant and slow fluctuation in the rate of cholesterol oxidation by FAD. The static disorder and dynamic disorder of reaction rates, which are essentially indistinguishable in ensemble-averaged experiments, were determined separately by the real-time single-molecule approach. A molecular memory phenomenon, in which an enzymatic turnover was not independent of its previous turnovers because of a slow fluctuation of protein conformation, was evidenced by spontaneous spectral fluctuation of FAD.
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Individual graphene layers in a multilayer graphene sample contribute their own edges. The edge of a graphene layer laid on an n layer graphene (nLG) is a building block for the edges of multilayer ...graphenes. We found that the D band observed from the edge of the top graphene layer laid on the nLG exhibits an identical line shape to that of disordered (n+1)LG. Based on the spectral features of the D and 2D bands, we identified two types of alignment configurations at the edges of bilayer and trilayer graphenes, whose edges are well-aligned from their optical images.
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