Magnetic irreversibility and magnetization processes in NiAl/NiO core/shell nanoparticle system.

This work brings out many interesting facets of magnetism in the NiAl/NiO core/shell nanoparticle system. Theandmagnetic irreversibility lines (TWI(H)andTSI(H)) reproduce the previously reported - phase diagram at fieldsH⩽30 Oe, but strong departures occur for > 30 Oe. Comparison with the theoretically predicted - phase diagram allows us to identifywithTCG+SG, where the paramagnetic (PM)-chiral glass () and PM-spin glass () phase transitions occur, andwith, the temperature at which transition to the replica symmetry breakingstate takes place.

Investigation of airborne spread of COVID-19 using a hybrid agent-based model: a case study of the UK.

Agent-based models have been proven to be quite useful in understanding and predicting the SARS-CoV-2 virus-originated COVID-19 infection. Person-to-person contact was considered as the main mechanism of viral transmission in these models. However, recent understanding has confirmed that airborne transmission is the main route to infection spread of COVID-19.

Enhancing adherence and management in patients with hypertension: Impact of form and frequency of knowledge intervention.

Background: The alarming rise in prevalence of hypertension warrants psychosocial methods supplementing pharmacotherapy for better management and prevention of cardiac emergencies. The objective of the study was to assess the differential impact of the form and frequency of knowledge intervention on management of primary hypertension.

Materials And Method: The study was conducted on 256 hypertensive patients recruited through purposive sampling at health centers in Hyderabad, India.

Knowledge, attitude, and practice of radiation oncologists during COVID-19 pandemic.

Background: Cancer care hospitals are taking measures to reduce the spread of COVID-19. Doctors and health-care workers might be suffering from burnout. Measures taken to reduce overcrowding in hospitals might be making access to essential cancer care difficult.

Quantification of niclosamide polymorphic forms - A comparative study by Raman, NIR and MIR using chemometric techniques.

Niclosamide, an anthelmintic drug recently repurposed for its activity against cancer, crystallizes into three solvated forms, two monohydrates (NHa, NHb) and one anhydrous (NAn) form. NAn is sensitive to pseudopolymorphic transformations that affect its dissolution and consequently, its bioavailability. NAn exhibits a polymorphic conversion to metastable monohydrate (NHa) form during high-energy milling in presence of poorly soluble solvents like water.

Cadmium and sodium adsorption properties of magnetite nanoparticles synthesized from Hevea brasiliensis Muell. Arg. bark: Relevance in amelioration of metal stress in rice.

Magnetite nanoparticles use for the remediation of toxic metal ions. Therefore, the scope of green synthesis of magnetite nanoparticles from Hevea bark extract, and application of these particles for the environmental remediation of Cd and Na tested. Mixing of 10.

Improved Stability of Tuberculosis Drug Fixed-Dose Combination Using Isoniazid-Caffeic Acid and Vanillic Acid Cocrystal.

The classic fixed-dose combination (FDC) of 4 tuberculosis drugs, namely rifampicin (RIF), isoniazid (INH), pyrazinamide (PZA), and ethambutol dihydrochloride (EDH) has the twin issues of physical stability and RIF cross-reaction in the 4-FDC. The major reason for these quality issues is the interaction between RIF and INH to yield isonicotinyl hydrazone in drug tablets. Pharmaceutical cocrystals of INH with caffeic acid (CFA) (PZA + EDH + RIF + INH-CFA cocrystal) and vanillic acid (VLA) (PZA + EDH + RIF + INH-VLA cocrystal) are able to stabilize the FDC formulation compared with the reference batch (PZA + EDH + RIF + INH).

Rufinamide: Crystal structure elucidation and solid state characterization.

Rufinamide (R) is a triazole derivative approved for the management of partial seizures and seizures associated with Lennox-Gastaut Syndrome, in November 2007. Crystal structure, solid state characterization, drug-excipient compatibility and solubility play a pivotal role in formulation development. This work deals with the crystal structure elucidation of R by single crystal X-ray diffraction and solid state characterization by thermal, spectroscopic and crystallographic techniques.

Acemetacin cocrystal structures by powder X-ray diffraction.

Cocrystals of acemetacin drug (ACM) with nicotinamide (NAM), -aminobenzoic acid (PABA), valerolactam (VLM) and 2-pyridone (2HP) were prepared by melt crystallization and their X-ray crystal structures determined by high-resolution powder X-ray diffraction. The powerful technique of structure determination from powder data (SDPD) provided details of molecular packing and hydrogen bonding in pharmaceutical cocrystals of acemetacin. ACM-NAM occurs in anhydrate and hydrate forms, whereas the other structures crystallized in a single crystalline form.

Spin Liquid State in the 3D Frustrated Antiferromagnet PbCuTe_{2}O_{6}: NMR and Muon Spin Relaxation Studies.

PbCuTe_{2}O_{6} is a rare example of a spin liquid candidate featuring a three-dimensional magnetic lattice. Strong geometric frustration arises from the dominant antiferromagnetic interaction that generates a hyperkagome network of Cu^{2+} ions although additional interactions enhance the magnetic lattice connectivity. Through a combination of magnetization measurements and local probe investigations by NMR and muon spin relaxation down to 20 mK, we provide robust evidence for the absence of magnetic freezing in the ground state.

Binary and ternary cocrystals of sulfa drug acetazolamide with pyridine carboxamides and cyclic amides.

A novel design strategy for cocrystals of a sulfonamide drug with pyridine carboxamides and cyclic amides is developed based on synthon identification as well as size and shape match of coformers. Binary adducts of acetazolamide (ACZ) with lactams (valerolactam and caprolactam, VLM, CPR), cyclic amides (2-pyridone, labeled as 2HP and its derivatives MeHP, OMeHP) and pyridine amides (nicotinamide and picolinamide, NAM, PAM) were obtained by manual grinding, and their single crystals by solution crystallization. The heterosynthons in the binary cocrystals of ACZ with these coformers suggested a ternary combination for ACZ with pyridone and nicotinamide.

A Brønsted Acid-Amino Acid as a Synergistic Catalyst for Asymmetric List-Lerner-Barbas Aldol Reactions.

Herein, for the first time, a combination of L-amino acid, (R)-5,5-dimethyl thiazolidinium-4-carboxylate (L-DMTC) with simple Brønsted acid TFA is reported as the suitable synergistic catalyst for the List-Lerner-Barbas aldol (LLB-A) reaction of less reactive 2-azidobenzaldehydes with various ketones at ambient temperature to furnish the optically active functionalized (2-azidophenyl)alcohols with very good yields, dr's, and ee's. This method gives first time access to the novel azido-containing multifunctional compounds, which are applicable in material to medicinal chemistry. Chiral functionalized (2-azidophenyl)alcohols were transformed into different molecular scaffolds in good yields with high selectivity through Lewis acid mediated NaBH4 reduction, aza-Wittig and Staudinger reaction (azide reduction), followed by oxidative cyclizations, allenone synthesis, and click reaction, respectively.

Observation of S = 1/2 quasi-1D magnetic and magneto-dielectric behavior in a cubic SrCuTe2O6.

We investigate the magnetic, thermal, and dielectric properties of SrCuTe2O6, which is isostructural to PbCuTe2O6, a recently found, Cu-based 3D frustrated magnet with a corner-sharing triangular spin network having dominant first and second nearest neighbor (nn) couplings (Koteswararao et al 2014 Phys. Rev. B 90 035141).

Modularity and three-dimensional isostructurality of novel synthons in sulfonamide-lactam cocrystals.

The design of novel supramolecular synthons for functional groups relevant to drugs is an essential prerequisite for applying crystal engineering in the development of novel pharmaceutical cocrystals. It has been convincingly shown over the past decade that molecular level control and modulation can influence the physicochemical properties of drug cocrystals. Whereas considerable advances have been reported on the design of cocrystals for carboxylic acids and carboxamide functional groups, the sulfonamide group, which is a cornerstone of sulfa drugs, is relatively unexplored for reproducible heterosynthon-directed crystal engineering.

Anomalous magnetoresistance in nanocrystalline gadolinium at low temperatures.

The results of a detailed investigation of electrical resistivity, ρ(T) and transverse magnetoresistance (MR) in nanocrystalline Gd samples with an average grain size d = 12 nm and 18 nm reveal the following. Besides a major contribution to the residual resistivity, ρ(r)(0), arising from the scattering of conduction electrons from grain surfaces/interfaces/boundaries (which increases drastically as the average grain size decreases, as expected), coherent electron-magnon scattering makes a small contribution to ρ(r)(0), which gets progressively suppressed as the applied magnetic field (H) increases in strength. At low temperatures (T ≲ 40 K) and fields (H = 0 and H = 5 kOe), ρ(H)(T) varies as T(3/2) with a change in slope at T(+) ≃ 16.

Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt.

Acemetacin (ACM) is a non-steroidal anti-inflammatory drug (NSAID), which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing.

Eutectics as improved pharmaceutical materials: design, properties and characterization.

Eutectics are a long known class of multi-component solids with important and useful applications in daily life. In comparison to other multi-component crystalline solids, such as salts, solid solutions, molecular complexes and cocrystals, eutectics are less studied in terms of molecular structure organization and bonding interactions. Classically, a eutectic is defined based on its low melting point compared to the individual components.

Stereoselective synthesis of five-membered spirooxindoles through Tomita zipper cyclization.

Functionalized five-membered spirooxindoles were furnished in good yields and excellent stereoselectivities by using an effective Tomita zipper cyclization (TZC) reaction through organophosphine catalysis.

Asymmetric synthesis of druglike six-membered spirooxindoles through an amino enyne catalysis.

An effective reflexive-Michael (r-M) reaction has been disclosed to access drug-like six-membered spirooxindoles in good yields and excellent enantioselectivities by using an aminoenyne-catalysis.

Solid-state form screen of cardiosulfa and its analogues.

Cardiosulfa is a biologically active sulfonamide molecule that was recently shown to induce abnormal heart development in zebrafish embryos through activation of the aryl hydrocarbon receptor (AhR). The present report is a systematic study of solid-state forms of cardiosulfa and its biologically active analogues that belong to the N-(9-ethyl-9H-carbazol-3-yl)benzene sulfonamide skeleton. Cardiosulfa (molecule 1; R(1) = NO2, R(2) = H, R(3) = CF3), molecule 2 (H, H, CF3), molecule 3 (CF3, H, H), molecule 4 (NO2, H, H), molecule 5 (H, CF3, H), and molecule 6 (H, H, H) were synthesized and subjected to a polymorph search and solid-state form characterization by X-ray diffraction, differential scanning calorimetry (DSC), variable-temperature powder X-ray diffraction (VT-PXRD), FTIR, and solid-state (ss) NMR spectroscopy.

Magnetization processes in nanocrystalline gadolinium.

The thermal decline in magnetization, M(T), at fixed magnetic field (H) under 'zero-field-cooled' (ZFC) and 'field-cooled' (FC) conditions, the time evolution of ZFC magnetization, M(ZFC)(t), at fixed temperature and field, M(H) hysteresis loops/isotherms, and ac susceptibility have been measured on polycrystalline Gd samples with average grain sizes of d = 12 and 18 nm. The irreversibility in magnetization, M(irr), occurring below a characteristic temperature that reduces with increasing H, is completely suppressed above a grain-size-dependent threshold field, H*. At low fields (H ≤ 100 Oe), M(irr)(T), like the coercive field, H(c)(T), exhibits a minimum at ∼16 K and a broad peak at ∼50 K before going to zero at T ≃ T(C) (Curie temperature).

Novel furosemide cocrystals and selection of high solubility drug forms.

Furosemide was screened in cocrystallization experiments with pharmaceutically acceptable coformer molecules to discover cocrystals of improved physicochemical properties, that is high solubility and good stability. Eight novel equimolar cocrystals of furosemide were obtained by liquid-assisted grinding with (i) caffeine, (ii) urea, (iii) p-aminobenzoic acid, (iv) acetamide, (v) nicotinamide, (vi) isonicotinamide, (vii) adenine, and (viii) cytosine. The product crystalline phases were characterized by powder x-ray diffraction, differential scanning calorimetry, infrared, Raman, near IR, and (13) C solid-state NMR spectroscopy.

Magnons as a Bose-Einstein condensate in nanocrystalline gadolinium.

The recent observation [S. P. Mathew et al.

Bose-Einstein condensation of magnons in polycrystalline gadolinium with nano-size grains.

We report the observation of Bose-Einstein condensation (BEC) of magnons in nanocrystalline Gd. Employing a self-consistent approach, the variations with magnetic field (H) of the BEC transition temperature, T(c)(H), and the volume, V (H), over which the condensate wavefunction retains its phase coherence, the temperature and magnetic field variations of the chemical potential, μ(T, H), and the average occupation number for the ground state, [linear span]n(0)(T, H)[linear span], are accurately determined from the magnetization, M(T, H), and specific heat, C(T, H), data. The variation of T(c) with magnetic field has the functional form T(c)(H) = T(c)(H = 0) + aH(2/3) that is characteristic of BEC.

Phase transformation in conformational polymorphs of nimesulide.

Nimesulide is a nonsteroidal anti-inflammatory drug (NSAID) and a COX-2 inhibitor. The native crystal structure of nimesulide (or Form I) has been characterized in the literature by X-ray powder diffraction (XRPD) lines, whereas full three-dimensional coordinates are known for a second polymorph (Form II). A detailed structural characterization and phase stability of nimesulide polymorphs were carried out.