Search

Er3+–Yb3+ co-doped NaGd(MoO4)2 phosphors with different concentrations of Er3+ and Yb3+ ions have been successfully synthesized via a high-temperature solid-state reaction method.

Most of us know turmeric (Curcuma longa) as the vibrant orange powder located in the spice section between thyme and vanilla beans. And many of us use turmeric root powder in our cooking, particularly if we have an affinity for preparing Indian–inspired dishes. Similar to the root–like component of its cousin ginger, turmeric has been a staple of Indian food traditions for millennia and has a long history of healing use (over 4000 years) in Ayurvedic, Traditional Chinese, and Siddhic medicinal traditions. Turmeric’s role in Hindu devotional and sacred ceremonies is alluded to by one of its Sanskrit names: Kanchani, the “Golden Goddess,” perhaps so called because its beautiful golden hue generously bestows healing to a wide range of ailments (Gallant, n.d.). Indeed, traditional Ayurvedic use includes turmeric as healing agent for skin abrasions, GI tract inflammation, aches and pains, and liver disorders, while modern research confirms the anti–bacterial, anti–inflammatory, and antioxidant properties of turmeric. The characteristic golden hue is produced by curcumin, the constituent in turmeric most isolated and studied by scientists, but the whole herb is used in herbal traditions and has also been the subject of many favorable studies. Turmeric’s Herbal Actions: Antioxidant and Anti–Inflammatory: Antioxidants scavenge free radicals and help to reduce or prevent damage and inflammation caused by free radicals, and anti–inflammatory agents block enzymes that promote inflammation and pain. Turmeric is often used in an Ayurvedic approach to reduce inflammation of the throat and tonsils, and as an anti–inflammatory herb for many other aches and pains. You will find that a number of culinary herbs also have antioxidant and anti–inflammatory properties, including sage, ginger, and garlic. Antimicrobial: Antimicrobial herbs inhibit the growth of pathogens like bacteria, viruses, and fungi. Cholerectic: Cholerectics stimulate production of bile, thereby supporting digestion. In Ayurveda, turmeric is a warming herb that kindles digestive fire, or agni. Like other bitter–flavored herbs that stimulate bile production, turmeric is used to promote digestion and alleviate symptoms in the GI tract. Turmeric offers such a dynamic array of health benefits that it’s even being studied in regards to its potential effect on serious diseases like cancer, Alzheimer’s, and heart disease. Cardiac specific benefits are its effects on cholesterol, triglycerides, and blood sugar. While studies do not show that it would be a good substitute for cholesterol and diabetes medications, long–term use may help reduce the amount of other medications used in a treatment level. How to Use Turmeric: Topical and External Use: Because of its antibacterial properties, when combined with a little salt and mixed together as a paste, turmeric can be applied to the skin in response to abrasions and swelling. This remedy is also used to help resolve bruises. Gargling with salt water is often thought to help relieve a sore throat. But turmeric, when paired with salt, has the potential to be even more effective! You can find turmeric at this link or at your local grocery store. Gargle With Turmeric and Salt: Ingredients: A pinch or two of turmeric, A pinch or two of salt, Add to warm water and gargle as you would regular salt water. Internal Use: The medicinal properties of turmeric may not be absorbed well due to its rapid metabolism in the liver and intestines unless it is consumed with black pepper. In a validating example of the time–tested concept of herbal catalysts (herbs that enhance the activity of other herbs), it turns out that the piperine in black pepper enhances the bioavailability of the curcumin in turmeric by 2000%. Whether by incorporating it into cooking or taking it as one of several herbs in a tea, turmeric is at the heart of many different remedies and continues to prove its value after thousands of years of use. One such tried and true recipe is “Golden Milk,” a traditional Ayurvedic concoction. Here is our take on this age–old recipe, with the addition of black pepper for enhanced curcumin bioavailability. This yummy, warming drink is delicious in the winter and can be served room temperature or slightly warmed if desired. turmeric for health – golden milk Turmeric Recipes: Traditional instructions recommend making a turmeric paste first, which can be spread on toast or added to other dishes, but you can also simply add turmeric powder into the milk. Turmeric Paste: Ingredients: ¼ cup ground turmeric, ½ cup water Directions: Combine turmeric powder and water in a saucepan. Simmer until mixture forms a thick paste. Let cool, then store in fridge. turmeric for health – golden milk Golden Milk: Serves one Ingredients: 1 cup unsweetened coconut, rice, or almond milk, ¼ – 1/2 teaspoon turmeric paste (or just add powder), 1 teaspoon coconut oil, Few shakes of ground black pepper, Generous dash of vanilla, Raw local honey or maple syrup to taste, Sprinkle of cinnamon Directions: Place 1 cup milk with turmeric paste, oil, black pepper, vanilla, and honey/maple syrup into a blender. Blend on high briefly until combined and foamy. Pour into cup, sprinkle with cinnamon, and serve. Safety: Turmeric eaten in food is considered safe. For some individuals, turmeric should not be used at high doses long term as overuse may cause gastrointestinal disturbances (e.g., diarrhea, nausea, ulcers) in some susceptible people Turmeric is considered contraindicated in the case of biliary tract obstruction due to potential bile–stimulating activity, and those with a history of biliary tract obstruction should gain professional advice before using turmeric at therapeutic doses. Because turmeric may have antiplatelet and blood–thinning activity, individuals on blood–thinning medications should exercise caution when considering therapeutic use and speak with their healthcare professional or pharmacist prior to self–administration. For similar reasons, it is also generally advised that individuals undergoing surgery stop consuming therapeutic doses of turmeric at least two weeks prior to their procedure. Eating foods with turmeric during pregnancy is generally considered safe, however turmeric should not be taken in high doses by pregnant women due to its potential emmenagogic effects. Lastly, one small study concluded that consumption of supplemental doses of turmeric can significantly increase urinary oxalate excretion which may subsequently increase risk of kidney stone formation in susceptible individuals.

Background Post hepatectomy liver failure (PHLF) remains a significant risk in patients undergoing curative liver resection for cancer, however currently available PHLF risk prediction investigations are not sufficiently accurate. The Hepatectomy risk assessment with functional magnetic resonance imaging trial (HEPARIM) aims to establish if quantitative MRI biomarkers of liver function & perfusion can be used to more accurately predict PHLF risk and FLR function, measured against indocyanine green (ICG) liver function test. Methods HEPARIM is an observational cohort study recruiting patients undergoing liver resection of 2 segments or more, prior to surgery patients will have both Dynamic Gadoxetate-enhanced (DGE) liver MRI and ICG testing. Day one post op ICG testing is repeated and R15 compared to the Gadoxetate Clearance (GC) of the future liver remnant (FLR-GC) as measure by preoperative DGE- MRI which is the primary outcome, and preoperative ICG R15 compared to GC of whole liver (WL-GC) as a secondary outcome. Data will be collected from medical records, biochemistry, pathology and radiology reports and used in a multi-variate analysis to the value of functional MRI and derive multivariant prediction models for future validation. Discussion If successful, this test will potentially provide an efficient means to quantitatively assess FLR function and PHLF risk enabling surgeons to push boundaries of liver surgery further while maintaining safe practice and thereby offering chance of cure to patients who would previously been deemed inoperable. MRI has the added benefit of already being part of the routine diagnostic pathway and as such would have limited additional burden on patients time or cost to health care systems. (Hepatectomy Risk Assessment With Functional Magnetic Resonance Imaging - Full Text View -ClinicalTrials.gov, n.d.) Trial registration ClinicalTrials.gov, ClinicalTrials.gov NCT04705194 - Registered 12th January 2021 – Retrospectively registered

Asiatic acid (AA), an aglycone of pentacyclic triterpene glycoside, obtained from the leaves of Centella asiatica exerts anticancer effects by inhibiting cellular proliferation and inducing apoptosis in a wide range of carcinogenic distresses. However, its chemotherapeutic efficacy is dampened by its low bioavailability. Polymeric nanoparticles (NPs) exhibit therapeutic efficacy and compliance by improving tissue penetration and lowering toxicity. Thus, to increase the therapeutic effectiveness of AA in the treatment of breast cancer, AA-loaded poly lactic-co-glycolic acid (PLGA) NPs (AA-PLGA NPs) have been formulated. The AA-PLGA NPs were characterized on the basis of their average particle size, zeta potential, electron microscopic imaging, drug loading, and entrapment efficiency. The NPs exhibited sustained drug release profile in vitro. Developed NPs exerted dose-dependent cytotoxicity to MCF-7 and MDA-MB-231 cells without damaging normal cells. The pro-oxidant and pro-apoptotic properties of AA-PLGA NPs were determined by the study of the cellular levels of SOD, CAT, GSH-GSSG, MDA, protein carbonylation, ROS, mitochondrial membrane potential, and FACS analyses on MCF-7 cells. Immunoblotting showed that AA-PLGA NPs elicited an intrinsic pathway of apoptosis in MCF-7 cells. In vivo studies on female BALB/c mice exhibited reduced volume of mammary pad tumor tissues and augmented expression of caspase-3 when administered with AA-PLGA NPs. No systemic adverse effect of AA-PLGA NPs was observed in our studies. Thus, AA-PLGA NPs can act as an efficient drug delivery system against breast cancer.

To determine if golden-angle radial sparse parallel (GRASP) dynamic contrast-enhanced (DCE)-MRI allows simultaneous evaluation of perfusion and morphology in liver fibrosis.Participants who were scheduled for liver biopsy or resection were enrolled (NCT02480972). Images were reconstructed at 12-s temporal resolution for morphologic assessment and at 3.3-s temporal resolution for quantitative evaluation. The image quality of the morphologic images was assessed on a four-point scale, and the Liver Imaging Reporting and Data System score was recorded for hepatic observations. Comparisons were made between quantitative parameters of DCE-MRI for the different fibrosis stages, and for hepatocellular carcinoma (HCCs) with different LR features.DCE-MRI of 64 participants (male = 48) were analyzed. The overall image quality consistently stood at 3.5 ± 0.4 to 3.7 ± 0.4 throughout the exam. Portal blood flow significantly decreased in participants with F2-F3 (n = 18, 175 ± 110 mL/100 mL/min) and F4 (n = 12, 98 ± 47 mL/100 mL/min) compared with those in participants with F0-F1 (n = 34, 283 ± 178 mL/100 mL/min, p0.05 for all). In participants with F4, the arterial fraction and extracellular volume were significantly higher than those in participants with F0-F1 and F2-F3 (p0.05). Compared with HCCs showing non-LR-M features (n = 16), HCCs with LR-M (n = 5) had a significantly prolonged mean transit time and lower arterial blood flow (p0.05).Liver MRI using GRASP obtains both sufficient spatial resolution for confident diagnosis and high temporal resolution for pharmacokinetic modeling. Significant differences were found between the MRI-derived portal blood flow at different hepatic fibrosis stages.A single MRI examination is able to provide both images with sufficient spatial resolution for anatomic evaluation and those with high temporal resolution for pharmacokinetic modeling. Portal blood flow was significantly lower in clinically significant hepatic fibrosis and mean transit time and extracellular volume increased in cirrhosis, compared with those in no or mild hepatic fibrosis. HCCs with different LR features showed different quantitative parameters of DCE-MRI: longer mean transit time and lower arterial flow were observed in HCCs with LR-M features.

Gene silencing is defined as epigenetic of gene expression leading to inactivation of previously active individual genes or larger chromosome regions. Silencing of a target gene can be achieved at two levels-transcriptional and post-transcriptional stages. The transcriptional gene silencing occurs through the repression of the process of transcription and the post transcriptional gene silencing occurs by the degradation of mRNA. There is also another type called Meiotic. Mechanisms responsible for repression of genes involve changes in level of DNA methylation and alterations in covalent modifications of histone proteins which leads to chromatin compaction. These are the effects of small RNA regulators such as small interfering RNAs (siRNAs), microRNAs (miRNA), Piwi-associated RNAs (piRNAs) etc. Virus can also conduct gene silencing which is known as Virus Induced Gene Silencing by cloning and inserting plant endogenous gene sequence in recombinant viral vectors. Even Gene Silencing helps in buildup resistance against biotic and abiotic stress and helps in knock down any kind of undesirable genes.

Bismuth selenide (Bi2Se3) is a 3D topological insulator, its strong spin-orbit coupling resulting in the well-known topologically protected coexistence of gapless metallic surface states and semiconducting bulk states with a band gap, Eg ≃ 300 meV. A fundamental question of considerable importance is how the electronic properties of this material evolve under nanoscale confinement. We report on catalyst-free, high-quality single-crystalline Bi2Se3 with controlled lateral sizes and layer thicknesses that could be tailored down to a few nanometers and a few quintuple layers (QLs), respectively. Energy-resolved photoabsorption spectroscopy (1.5 eVE(photon)6 eV) of these samples reveals a dramatic evolution of the photon absorption spectra as a function of size, transitioning from a featureless metal-like spectrum in the bulk (corresponding to a visually gray color), to one with a remarkably large band gap (Eg ≥ 2.5 eV) and a spectral shape that correspond to orange-red colorations in the smallest samples, similar to those seen in semiconductor nanostructures. We analyze this colorful transition using ab initio density functional theory and tight-binding calculations which corroborate our experimental findings and further suggest that while purely 2D sheets of few QL-thick Bi2Se3 do exhibit small band gaps that are consistent with previous ARPES results, the presently observed large gaps of a few electronvolts can only result from a combined effect of confinement in all three directions.

We stand at the threshold of a new ‘golden age’ of spectroscopic studies of materials for unraveling how charge, spin, orbital and lattice degrees of freedom interact to produce emergent phenomena and exotic states of matter. In this connection, the need for proper modeling of various highly resolved spectroscopies is becoming of critical importance in providing discriminating tests of competing theoretical models and as a rational basis for future experimentation. Here we present an overview of our modeling efforts aimed at obtaining a realistic description of various highly resolved spectroscopies in complex materials with illustrative examples drawn from angle-resolved photoemission studies of the cuprate high-temperature superconductors.

We discuss a comprehensive scheme for modeling various highly resolved spectroscopies of the cuprates where effects of matrix element, crystal structure, strong electron correlations, and superconductivity are included realistically in material-specific detail. A number of illustrative examples drawn from our recent work are presented. Specific issues in the cuprate physics considered are: (i) Origin of high-energy kink or the waterfall effect; (ii) Dichroic effects in angle-resolved photoemission spectrum; (iii) Asymmetry of the scanning tunneling spectrum between the processes of electron extraction and injection; (iv) Persistence of ‘Mott’ like high-energy features with doping in optical spectra; (v) Magnetic excitations in electron and hole doped cuprates.

We demonstrate that many features ascribed to strong correlation effects in various spectroscopies of the cuprates are captured by a calculation of the self-energy incorporating effects of spin and charge fluctuations. The self-energy is calculated over the full doping range from half-filling to the overdoped system. In the normal state, the spectral function reveals four subbands: two widely split incoherent bands representing the remnant of the two Hubbard bands, and two additional coherent, spin- and charge-dressed in-gap bands split by a spin-density wave, which collapses in the overdoped regime. The resulting coherent subbands closely resemble our earlier mean-field results. Here we present an overview of the combined results of our mean-field calculations and the newer extensions into the intermediate coupling regime.

LiFePO4 is a battery cathode material with high safety standards due to its unique electronic structure. We performed systematic experimental and theoretical studies based on soft X-ray emission, absorption, and hard X-ray Raman spectroscopy of LixFePO4 nanoparticles and single crystals. The results clearly show a non-rigid electron-state reconfiguration of both the occupied and unoccupied Fe-3d and O-2p states during the (de)lithiation process. We focus on the energy configurations of the occupied states of LiFePO4 and the unoccupied states of FePO4, which are the critical states where electrons are removed and injected during the charge and discharge process, respectively. In LiFePO4, the soft X-ray emission spectroscopy shows that, due to the Coulomb repulsion effect, the occupied Fe-3d states with the minority spin sit close to the Fermi level. In FePO4, the soft X-ray absorption and hard X-ray Raman spectroscopy show that the unoccupied Fe-3d states again sit close to the Fermi level. These critical 3d electron state configurations are consistent with the calculations based on modified Becke and Johnson potentials GGA+U (MBJGGA+U) framework, which improves the overall lineshape prediction compared with the conventionally used GGA+U method. The combined experimental and theoretical studies show that the non-rigid electron state reshuffling guarantees the stability of oxygen during the redox reaction throughout the charge and discharge process of LiFePO4 electrodes, leading to the intrinsic safe performance of the electrodes.

The topology of a topological material can be encoded in its surface states. These surface states can only be removed by a bulk topological quantum phase transition into a trivial phase. Here we use photoemission spectroscopy to image the formation of protected surface states in a topological insulator as we chemically tune the system through a topological transition. Surprisingly, we discover an exotic spin-momentum locked, gapped surface state in the trivial phase that shares many important properties with the actual topological surface state in anticipation of the change of topology. Using a spin-resolved measurement, we show that apart from a surface bandgap these states develop spin textures similar to the topological surface states well before the transition. Our results offer a general paradigm for understanding how surface states in topological phases arise from a quantum phase transition and are suggestive for the future realization of Weyl arcs, condensed matter supersymmetry and other fascinating phenomena in the vicinity of a quantum criticality., In topological insulators, topology imposes a quantum phase transition between the trivial and nontrivial phases. Here, Xu et al. demonstrate how properties of the topological surface states emerge in the trivial phase of BiTl(S1-δSeδ)2 when close to its chemically tuned phase transition.

We report the evolution of the surface electronic structure and surface material properties of a topological crystalline insulator (TCI) Pb1-xSnxSe as a function of various material parameters including composition x, temperature T and crystal structure. Our spectroscopic data demonstrate the electronic groundstate condition for the saddle point singularity, the tunability of surface chemical potential, and the surface states' response to circularly polarized light. Our results show that each material parameter can tune the system between trivial and topological phase in a distinct way unlike as seen in Bi2Se3 and related compounds, leading to a rich and unique topological phase diagram. Our systematic studies of the TCI Pb1-xSnxSe are valuable materials guide to realize new topological phenomena., Comment: 10 pages, 7 figures. Expanded version of arXiv:1403.1560

Nanocrystalline MFe2O4 (M=Co, Ni) particles are synthesized by citrate precursor technique. Mossbauer and magnetic studies are carried out with the CoFe2O4 samples having particle sizes of 9, 14 and 30 nm and the NiFe2O4 samples having particle sizes of 9, 21 and 30 nm. The intrinsic magnetic parameters are found to vary with the particle size. The magnetic interactions and cation distribution present in these systems influence the room temperature Mossbauer parameters. Ferrimagnetic sextets are observed for all the different particle sizes. The observed reduction of the magnetic hyperfine field values with the decrease in the size of MFe2O4 particles are attributed to the intrinsic size effect and the canted spin structure at the surface of the nanoparticles.

Understanding the spin-texture behavior of boundary modes in ultrathin topological insulator films is critically essential for the design and fabrication of functional nano-devices. Here by using spin-resolved photoemission spectroscopy with p-polarized light in topological insulator Bi2Se3 thin films, we report tunneling-dependent evolution of spin configuration in topological insulator thin films across the metal-to-insulator transition. We observe strongly binding energy- and wavevector-dependent spin polarization for the topological surface electrons in the ultra-thin gapped-Dirac-cone limit. The polarization decreases significantly with enhanced tunneling realized systematically in thin insulating films, whereas magnitude of the polarization saturates to the bulk limit faster at larger wavevectors in thicker metallic films. We present a theoretical model which captures this delicate relationship between quantum tunneling and Fermi surface spin polarization. Our high-resolution spin-based spectroscopic results suggest that the polarization current can be tuned to zero in thin insulating films forming the basis for a future spin-switch nano-device., To appear in Nature Communications (2014); Expanded version of http://arxiv.org/abs/1307.5485

We present an approximation for efficient calculation of the Lindhard susceptibility $\chi^{L}(q,\omega)$ in a periodic system through the use of simple products of real space functions and the fast Fourier transform (FFT). The method is illustrated by providing $\chi^{L}(q,\omega)$ results for the electron doped cuprate Nd$_{2-x}$Ce$_{x}$CuO$_{4}$ extended over several Brillouin zones. These results are relevant for interpreting inelastic X-ray scattering spectra from cuprates., Comment: 6 pages, 6 figures, accepted in Physical Review B

We present a computation of Cu K-edge resonant inelastic x-ray scattering (RIXS) spectra for electron-doped cuprates which includes coupling to bosonic fluctuations. Comparison with experiment over a wide range of energy and momentum transfers allows us to identify the signatures of three key normal-state energy scales: the pseudogap, charge transfer gap, and Mott gap. The calculations involve a three band Hubbard Hamiltonian based on Cu $d_{x^2-y^2}$ and O $p_x$, $p_y$ orbitals, with a self-energy correction which arises due to spin and charge fluctuations. Our theory reproduces characteristic features e.g., gap collapse, large spectral weight broadening, and spectral weight transfer as a function of doping, as seen in experiments., 5 pages, 4 figures

We have investigated the nature of surface states in the Bi2Te3 family of three-dimensional topological insulators using first-principles calculations as well as model Hamiltonians. When the surface Dirac cone is warped due to Dresselhaus spin-orbit coupling in rhombohedral structures, the spin acquires a finite out-of-plane component. We predict a novel in-plane spin-texture of the warped surface Dirac cone with spins not perpendicular to the electron momentum. Our k.p model calculation reveals that this novel in-plane spin-texture requires high order Dresselhaus spin-orbit coupling terms., Comment: 4 pages, 3 figures

International audience; The high-temperature superconducting cuprate La2−xSrxCuO4 (LSCO) shows several phases ranging from antiferromagnetic insulator to metal with increasing hole doping. To understand how the nature of the hole state evolves with doping, we have carried out high-resolution Compton scattering measurements at room temperature together with first-principles electronic structure computations on a series of LSCO single crystals in which the hole doping level varies from the underdoped (UD) to the overdoped (OD) regime. Holes in the UD system are found to primarily populate the O 2px /py orbitals. In contrast, the character of holes in the OD system is very different in that these holes mostly enter Cu d orbitals. High-resolution Compton scattering provides a bulk-sensitive method for imaging the orbital character of dopants in complex materials.

We study interference patterns of a magnetically doped topological insulator Bi(2-x)Fe(x)Te(3+d) by using Fourier transform scanning tunneling spectroscopy and observe several new scattering channels. A comparison with angle-resolved photoemission spectroscopy allows us to unambiguously ascertain the momentum-space origin of distinct dispersing channels along high-symmetry directions and identify those originating from time-reversal symmetry breaking. Our analysis also reveals that the surface state survives far above the energy where angle-resolved photoemission spectroscopy finds the onset of continuum bulk bands.