We provide the first experimental evidence of oxygen vacancy defect induced ferromagnetism in undoped multiferroic CaMn7O12 (CMO) manganite synthesized from the facile chemical combustion method. The ...obtained nanocrystalline is characterized by various techniques like TGA, FTIR, XRD, SEM-EDX, AFM, UV-visible, XPS, and SQUID, etc. to confirm the phase purity and crystallinity of CMO. Surface roughness increases with sintering time attributed to the increase of surface oxygen vacancy defects. X-ray photoelectron spectroscopy was carried out to confirm the oxidation state of constituent elements and also provides direct evidence of enhanced oxygen vacancies. UV–vis optical absorption used to infer band gap shift from 1.68 to 1.38 eV, respectively, is also attributed to increases in oxygen vacancy defects. Multiple magnetic phase transition temperatures of 90, 50, and 42 K, respectively, were obtained from the derivative of magnetization. A systematic decrease of full widths at half maxima (fwhm) of dM/dT vs T curves with sintering time indicates strengthening of ferromagnetism (FM). Transition temperature does not change significantly with sintering time, indicating the extrinsic origin of FM. The results of the UV–vis, XPS, and AFM and strengthening of ferromagnetism all are corroborated with each other’s results and also attribute to enhanced oxygen vacancy concentration with sintering time. The origin of FM in undoped CMO manganite with sintering time results from bound magnetic polarons (BMPs) of enhanced iterant and the localized electron of oxygen vacancies trapped center at the surface or interfaces. Our finding also opens a new perspective for exploiting oxygen vacancy defect engineering at surfaces or interfaces in the design of exotic magnetic- and spintronics-based devices.
Uric acid, generated from the metabolism of purines, has proven and emerging roles in human disease. Serum uric acid is determined by production and the net balance of reabsorption or secretion by ...the kidney and intestine. A detailed understanding of epithelial absorption and secretion of uric acid has recently emerged, aided in particular by the results of genome-wide association studies of hyperuricemia. Novel genetic and regulatory networks with effects on uric acid homeostasis have also emerged. These developments promise to lead to a new understanding of the various diseases associated with hyperuricemia and to novel, targeted therapies for hyperuricemia.
Bi1–xBaxFeO3 (0.0≤x≤0.25) ceramics are prepared by chemical synthesis route. At room temperature, antiferromagnetic BiFeO3 is converted to ferromagnetic on doping Ba. A large change in the ...magnetization is observed around 370°C which is close to the Neel temperature (TN) of parent compound. Another magnetic transition is also observed near 600°C. Spin canting or impurity phase could be a probable reason for the origin of ferromagnetism in both cases. Ferroelectric and magnetic transitions of the compounds shift towards higher temperature with Ba-doping concentration. Anomaly in the dielectric constant is also observed near the TN of BiFeO3. The composition x=0.15 shows the maximum magnetic moment at room temperature while better fatigue resistance and maximum magnetoelectric coupling are observed for x=0.20 composition.
► Here we have synthesized Ba doped bismuth ferrite (BFO) sample of different compositions with chemical route. ► Structural analysis shows an increase in lattice parameter due to doping of barium replacing Bi in the parent compound. ► Large change in multiferroic property is observed. ► Two magnetic transitions one at near Neel temperature of BFO and another at higher temperature (∼600°C) are observed. ► Dielectric anomaly also takes place near this temperature. Sample with Ba concentration 0.20 shows good fatigue resistance.
Cerebral stroke is the leading cause of death and permanent disability among elderly people. In both humans and animals, cerebral ischemia damages the nerve cells in vulnerable regions of the brain, ...viz., hippocampus, cerebral cortex, cerebellum, and hypothalamus. The present study was conducted to evaluate the therapeutic efficacy of nanoencapsulated quercetin (QC) in combating ischemia-reperfusion-induced neuronal damage in young and aged Swiss Albino rats. Cerebral ischemia was induced by occlusion of the common carotid arteries of both young and aged rats followed by reperfusion. Nanoencapsulated quercetin (2.7 mg/kg b wt) was administered to both groups of animals via oral gavage two hours prior to ischemic insults as well as post-operation till day 3. Cerebral ischemia and 30 min consecutive reperfusion caused a substantial increase in lipid peroxidation, decreased antioxidant enzyme activities and tissue osmolality in different brain regions of both groups of animals. It also decreased mitochondrial membrane microviscosity and increased reactive oxygen species (ROS) generation in different brain regions of young and aged rats. Among the brain regions studied, the hippocampus appeared to be the worst affected region showing increased upregulation of iNOS and caspase-3 activity with decreased neuronal count in the CA1 and CA3 subfields of both young and aged rats. Furthermore, three days of continuous reperfusion after ischemia caused massive damage to neuronal cells. However, it was observed that oral treatment of nanoencapsulated quercetin (2.7 mg/kg b wt) resulted in downregulation of iNOS and caspase-3 activities and improved neuronal count in the hippocampal subfields even 3 days after reperfusion. Moreover, the nanoformulation imparted a significant level of protection in the antioxidant status in different brain regions, thus contributing to a better understanding of the given pathophysiological processes causing ischemic neuronal damage.
Feynman integrals obey linear relations governed by intersection numbers, which act as scalar products between vector spaces. We present a general algorithm for the construction of multivariate ...intersection numbers relevant to Feynman integrals, and show for the first time how they can be used to solve the problem of integral reduction to a basis of master integrals by projections, and to directly derive functional equations fulfilled by the latter. We apply it to the decomposition of a few Feynman integrals at one and two loops, as first steps toward potential applications to generic multiloop integrals. The proposed method can be more generally employed for the derivation of contiguity relations for special functions admitting multifold integral representations.
A
bstract
We elaborate on the recent idea of a direct decomposition of Feynman integrals onto a basis of master integrals on maximal cuts using intersection numbers. We begin by showing an ...application of the method to the derivation of contiguity relations for special functions, such as the Euler beta function, the Gauss
2
F
1
hypergeometric function, and the Appell
F
1
function. Then, we apply the new method to decompose Feynman integrals whose maximal cuts admit 1-form integral representations, including examples that have from two to an arbitrary number of loops, and/or from zero to an arbitrary number of legs. Direct constructions of differential equations and dimensional recurrence relations for Feynman integrals are also discussed. We present two novel approaches to decomposition-by-intersections in cases where the maximal cuts admit a 2-form integral representation, with a view towards the extension of the formalism to
n
-form representations. The decomposition formulae computed through the use of intersection numbers are directly verified to agree with the ones obtained using integration-by-parts identities.
The aim of this study was to comprehensively delineate iron metabolism and its implications in patients with chronic heart failure (CHF).
Iron deficiency is an emerging therapeutic target in CHF.
...Iron and clinical indexes were quantified in 157 patients with CHF.
Several observations were made. First, iron homeostasis was deranged in anemic and nonanemic subjects and characterized by diminished circulating (transferrin saturation) and functional (mean cell hemoglobin concentration) iron status in the face of seemingly adequate stores (ferritin). Second, while iron overload and elevated iron stores were rare (1%), iron deficiency (transferrin saturation <20%) was evident in 43% of patients. Third, disordered iron homeostasis related closely to worsening inflammation and disease severity and strongly predicted lower hemoglobin levels independently of age, sex, erythrocyte sedimentation rate, New York Heart Association (NYHA) functional class, and creatinine. Fourth, the etiologies of anemia varied with disease severity, with an iron-deficient substrate (anemia of chronic disease and/or iron-deficiency anemia) evident in 16%, 72%, and 100% of anemic NYHA functional class I or II, III, and IV patients, respectively. Although anemia of chronic disease was more prevalent than iron-deficiency anemia, both conditions coexisted in 17% of subjects. Fifth, iron deficiency was associated with lower peak oxygen consumption and higher ratios of ventilation to carbon dioxide production and identified those at enhanced risk for death (hazard ratio: 3.38; 95% confidence interval: 1.48 to 7.72; p = 0.004) independently of hemoglobin. Nonanemic iron-deficient patients had a 2-fold greater risk for death than anemic iron-replete subjects.
Disordered iron homeostasis in patients with CHF relates to impaired exercise capacity and survival and appears prognostically more ominous than anemia.
Perovskite quantum dots (PQDs) are known to be defect-tolerant, possessing a clean band gap with optically inactive benign defect states. However, we show that there exist significant deep trap ...states beyond the conduction band minimum, although the extent of shallow trap states is observed to be minimal. The extent of deep trap states beyond the conduction band minimum seems to be significant in PQDs; however, the extent is less than that of even optically robust CdSe- and InP-based core/alloy-shell QDs. In-depth analyses based on ultrafast transient absorption and ultrasensitive single-particle spectroscopic investigations decode the underlying degree of charge carrier recombination in CsPbBr3 PQDs, which is quite important for energy applications.
Using achiral components, a V-shaped dicarboxylic acid (H2L) and a conformationally flexible bidentate linker (bpp), a thermally stable chiral metal organic framework {Cd(bpp)(L)(H2O)·DMF} n (1), ...where H2L = 4,4′-(dimethylsilanediyl)bis-benzoic acid, bpp = 1,3-bis(4-pyridyl)propane and DMF = N,N-dimethylformamide, has been solvothermally synthesized and crystallographically characterized. It consists of 1D helical chains linked at the cadmium centers resulting in an overall 2D framework. Its microporous nature was confirmed by gas-sorption measurements. Upon thermal activation of 1, where both guest DMF molecules present in the 1D open channels and the coordinated H2O molecules are removed, its active metal site shows Lewis acid character to be an excellent heterogeneous catalyst for the C–C (Knoevenagel condensation reaction) and C–N (Strecker) bond forming reactions.
A
bstract
The computation of Feynman integrals is often the bottleneck of multi-loop calculations. We propose and implement a new method to efficiently evaluate such integrals in the physical region ...through the numerical integration of a suitable set of differential equations, where the initial conditions are provided in the unphysical region via the sector decomposition method. We present numerical results for a set of two-loop integrals, where the non-planar ones complete the master integrals for
gg
→
γγ
and
q
q
¯
→
γγ
scattering mediated by the top quark.
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