Exploration of the structural, optoelectronic, magnetic, elastic, vibrational, and thermodynamic properties of molybdenum-based chalcogenides A2MoSe4 (A =Li, K) for photovoltaics and spintronics applications: a first-principle study.

CONTEXT: In the present work, the cubic phase of the chalcogenide materials, i.e., A2MoSe4 (A =Li, K) is examined to explore the structural, optoelectronic, magnetic, mechanical, vibrational, and thermodynamic properties. The lattice parameters for Li2MoSe4 are found to be a= 7.62 Å with lattice angles of α=ß=γ=90° whereas for K2MoSe4, a= 8.43 Å, and α=ß=γ=90°. These materials are categorized as semiconductors because Li2MoSe4 and K2MoSe4 exhibit direct energy band gap worth 1.32 eV and 1.61 eV, respectively through HSE06 functional. The optical analysis has declared them efficient materials for optoelectronic applications because both materials are found to be effective absorbers of ultraviolet radiations. These materials are noticed to be brittle while possessing anisotropic behavior for various mechanical applications. The vibrational properties are explored to check the thermal stability of the materials. On the basis of thermodynamics and heat capacity response, Li2MoSe4 is more stable than K2MoSe4. The results of our study lay the groundwork for future research on the physical characteristics of ternary transition metal chalcogenides (TMC). METHODS: These physical properties are explored for the first time while using a first-principles approach based on density functional theory (DFT) in the framework of Cambridge Serial Total Energy Package (CASTEP) by Perdew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA) functional. However, GGA+U and HSE06 are also employed to improve electronic properties. Kramers-Kronig relations are used to evaluate the dielectric function with a smearing value of 0.5 eV. Voigt-Reuss-Hill approximation is used for seeking the elastic response of these materials. The thermodynamic response is sought by harmonic approximation. The density functional perturbation theory (DFPT) approach is used for investigating atomic vibrations.

Ab-initio exploration of unique and substantial computational properties of double hydrides Cs2CaTlH6, Cs2SrTlH6, & Cs2BaTlH6, for the computational manufacturing of hydrogen fuel cell: A DFT study.

In the present article, the DFT based computational manufacturing for hydrogen fuel cell has been performed because hydrogen storage applications as one of the utmost explored research fields of the modern era. The discovery of novel and potential hydride perovskites materials has developed the current attention for hydrogen fuel cell and related applications. The double hydride perovskite Cs2CaTlH6, Cs2SrTlH6, Cs2BaTlH6 materials are promising for the computational manufacturing of hydrogen fuel cell because calculated tolerance factors for the considered materials are listed as Cs2CaTlH6 (0.90) > Cs2SrTlH6 (0.86) > Cs2BaTlH6 (0.84) illustrating the structure stability and compatibility along with metallic electronic behavior favorable for hydrogen storage devices. The mechanical parameters for the considered materials are also calculated to encounter the Born reliability, stability and compatibility criterion. The Pugh's ratio, poison coefficient and Cauchy pressure calculations confirmed the brittle character favorable for hydrogen fuel cell. Furthermore, gravimetric ratios recommended that the considered materials are suitable and favorable for hydrogen fuel cell as hydrogen fuel can sustain for longer time and contribute extraordinary assistances in transportation handling applications and multiplicity of power. In addition, the considered materials are thermodynamic and vibrational symmetry as no soft (imaginary) mode of phonon in dispersion curve is observed. In short, the considered materials Cs2CaTlH6, Cs2SrTlH6, Cs2BaTlH6 are novel, significant and potential candidates for the hydrogen fuel cell and motivate the experimental researcher to synthesize these materials for experimental manufacturing of hydrogen fuel cell to meet the energy demand of the present day.

Correction: An ab initio investigation of the structural, mechanical, electronic, optical, and thermoelectric characteristics of novel double perovskite halides Cs2CaSnX6 (X = Cl, Br, I) for optically influenced RRAM devices.

[This corrects the article DOI: 10.1039/D3RA00078H.].

An ab initio investigation of the structural, mechanical, electronic, optical, and thermoelectric characteristics of novel double perovskite halides Cs2CaSnX6 (X = Cl, Br, I) for optically influenced RRAM devices.

Hybrid lead halide perovskites have been considered as promising candidates for a large variety of optoelectronic applications. By exploring novel combinations of lead-free double perovskite halides, it is possible to find a suitable replacement for poisonous lead halide perovskites, enhancing electronic and optical response for their application as optically-influenced resistive switching random access memory (RRAM). In this work, the structural, mechanical, elastic, electronic, optical, and thermoelectric characteristics of lead-free double halide perovskites were investigated by Vienna ab initio simulation package (VASP) to explore their role in RRAM. From the analysis of mechanical constraints, it is clear that all three composites of Cs2CaSnX6 (X = Cl, Br, I) are mechanically stable and ductile in nature. The electronic bandgap with and without spin-orbit coupling (SOC), and total and sub-total density of states (TDOS, sub-TDOS) have been calculated using the Perdew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA) potentials. The observed direct band gaps of 3.58 eV, 3.09 eV, and 2.60 eV for Cs2CaSnCl6, Cs2CaSnBr6, and Cs2CaSnI6, respectively, reveal the suitability of these specified composites as resistive switching material for RRAM devices. Additionally, the optical characteristics, such as complex refractive index, absorption coefficient, and reflectivity of the compounds under consideration have been calculated under the action of incident photons of 0 to 14 eV energy. The thermoelectric properties of Cs2CaSnX6 (X = Cl, Br, I) double perovskite halide were computed and analyzed with the help of the BoltzTraP Code.

Improved resistive switching characteristics of a multi-stacked HfO2/Al2O3/HfO2 RRAM structure for neuromorphic and synaptic applications: experimental and computational study.

Atomic Layer Deposition (ALD) was used for a tri-layer structure (HfO2/Al2O3/HfO2) at low temperature over an Indium Tin Oxide (ITO) transparent electrode. First, the microstructure of the fabricated TaN/HfO2/Al2O3/HfO2/ITO RRAM device was examined by the cross-sectional High-Resolution Transmission Electron Microscopy (HRTEM). Then, Energy Dispersive X-ray Spectroscopy (EDS) was performed to probe compositional mapping. The bipolar resistive switching mode of the device was confirmed through SET/RESET characteristic plots for 100 cycles as a function of applied biasing voltage. An endurance test was performed for 100 DC switching cycles @0.2 V wherein; data retention was found up to 104 s. Moreover, for better insight into the charge conduction mechanism in tri-layer HfO2/Al2O3/HfO2, based on oxygen vacancies (VOX), total density of states (TDOS), partial density of states (PDOS) and isosurface three-dimensional charge density analysis was performed using WEIN2k and VASP simulation packages under Perdew-Burke-Ernzerhof _Generalized Gradient approximation (PBE-GGA). The experimental and theoretical outcomes can help in finding proper stacking of the active resistive switching (RS) layer for resistive random-access memory (RRAM) applications.

DFT-based study of the structural, optoelectronic, mechanical and magnetic properties of Ti3AC2 (A = P, As, Cd) for coating applications.

The first-principles approach has been used while employing the Perdew-Burke-Ernzerhof exchange-correlation functional of generalized gradient approximation (PBE-GGA) along with the Hubbard parameter to study the structural, optoelectronic, mechanical and magnetic properties of titanium-based MAX materials Ti3AC2 (A = P, As, Cd) for the first time. As there is no band gap found between the valence and conduction bands in the considered materials, these compounds belong to the conductor family of materials. A mechanical analysis carried out at pressures of 0 GPa to 20 GPa and the calculated elastic constants C ij reveal the stability of these materials. Elastic parameters, i.e., Young's, shear and bulk moduli, anisotropy factor and Poisson's ratio, have been investigated in the framework of the Voigt-Reuss-Hill approximation. The calculated values of relative stiffness are found to be greater than ½ for Ti3PC2 and Ti3AsC2, which indicates that these compounds are closer to typical ceramics, which possess low damage tolerance and fracture toughness. Optical parameters, i.e., dielectric complex function, refractive index, extinction coefficient, absorption coefficient, loss function, conductivity and reflectivity, have also been investigated. These dynamically stable antiferromagnetic materials might have potential applications in advanced electronic and magnetic devices. Their high strength and significant hardness make these materials potential candidates as hard coatings.

ab initio study of oxygen vacancy effects on structural, electronic and thermoelectric behavior of AZr1-xMxO3 (A = Ba, Ca, Sr; M= Al, Cu, x = 0.25) for application of memory devices.

The structural, electronic and thermoelectric properties of AZr1-xMxO3 (A = Ba, Ca, Sr; M = Al, Cu, x = 0.25) without and with an oxygen vacancy (Vo) have been unveiled using the Perdew-Burke-Ernzerhof Generalized Gradient Approximation (PBE-GGA) functional along with Tran-Blaha modified Becke-Jonhson (TB-mBJ)approximation based on Density Functional Theory (DFT) in the framework of WIEN2k code for memristors applications. Moreover, isosurface charge density plots have been calculated by using Vienna ab initio Simulation Package (VASP) simulation code. The analysis of structural parameters reveals that substituting Zr4+ with Al3+ and Cu2+ causes the lattice distortion which tends to increase in the presence of Vo along with dopant. The study of band structure, density of states (DOS) and isosurface charge density plots predict the enhanced charge conduction and formation of conducting filaments (CFs) for all composites with dopant and/or Vo. Moreover, spin polarized density of states for Cu doped composites has also been calculated to confirm the large exchange splitting of Cu-3d states. The thermoelectric characteristics of considered composites have also been explored using the Boltztrap code to better explain the semi-classical Boltzmann transport theory. Thermoelectric parameters confirm the semiconductor nature of all composites, ensuring the compatibility for memristors and thermoelectric devices applications. In addition to this spin polarized thermoelectric behavior of Cu doped composites that ensure the contribution of spin down (↓) states of Cu for charge transport mechanism. The SrZrCuO3+Vo composite is found most promising candidate followed by BaZrCuO3 for memristors applications while, CaZrCuO3 is found most suitable amongst studied composites for thermoelectric devices.

Ab-initio prediction of the mechanical, magnetic and thermoelectric behaviour of perovskite oxides XGaO3 (X = Sc, Ti, Ag) using LDA+U functional: For optoelectronic devices.

The mechanical, magnetic and thermoelectric properties of spin polarized XGaO3 (X = Sc, Ti, Ag) perovskite oxides in cubic phase have been investigated using LDA + U functional through ab-initio study based on density functional theory (DFT) in the framework of WIEN2K simulation code. The Full Potential Linearized Augmented Plane Wave (FP-LAPW) technique along with PBE-GGA functional have been used to optimize the systems and determining exchange-correlation potential. However, in order to address on-site self-interactions error and overcome limitations of PBE-GGA functional, LDA + U has been employed because Hubbard parameter 'U' is found an appropriate remedy to consider on-site self-interactions, and to calculate improved electronic energy band gap. All spin polarized band structures reveal indirect band gap with different energies Eg (eV) such as ↑↓ 0.98 eV for ScGaO3, ↑1.05 eV and ↓1.70 eV for TiGaO3, ↑1.13 eV and ↓2.19 eV for AgGaO3. Thus, all compounds are semiconductor in nature. The analysis of spin polarized total and partial density of states unveil that ScGaO3 is non-magnetic material, whereas, TiGaO3 and AgGaO3 are characterized by strong exchange splitting of 3d (Ti) and 4d (Ag) states with significant spin magnetic moments, i.e., 1.0002 µB and -2.0002 µB, respectively. The elastic constants, i.e., Bulk, Young and Shear moduli, Poisson's coefficient, Anisotropy factor, Pugh's ratio, Cauchy pressure and melting temperature are calculated through Viogt-Reuss-Hill approximation. The thermoelectric response of the considered perovskites has been determined through semi-classical Boltzmann transport theory in the framework of BoltzTraP simulation code. Basic understandings of the mechanical, magnetic and thermoelectric properties of these compounds are studied for the first time in this manuscript.

Ab-initio prediction of structure stability, electromagnetic, optical and thermoelectric behavior of orthorhombic LaXO3 (X= Cr, Mn, Fe): For device application.

In this paper, theoretical calculations for electronic band structure, the density of states, the optical and thermoelectric response of orthorhombic LaXO3 (X = Cr, Mn, Fe) compounds are calculated. The Full Potential Linearized Augmented Plane Wave plus local orbital (FP-LAPW + lo) method is used in the context of density functional theory. Band gaps of three compounds are determined using Wu Cohen Generalized Gradient approximation with additional U potential (WC-GGA + U). Ferromagnetism is observed due to strong p-d hybridization and is justified by observed magnetic moments across individual atoms and at interstitial regions, and exchange constants are also reported. Optical properties are explained by calculating real and imaginary parts of the dielectric function, refractive index (n), extinction coefficient (k), reflection coefficient (R), the absorption coefficient (α), and energy loss spectrum (L). High value of dielectric constant, very small reflectivity and lower energy loss factor in, visible to ultraviolet region favours them for optoelectronic devices. We also computed the thermoelectric properties, including Seebeck coefficient, thermal and electrical conductivity and power factor as a function of temperature by combining results from DFT and Boltzmann transport theory. The phonon dispersion curve shows the stability of the current structures.

First principle study of electronic, mechanical, optical and thermoelectric properties of CsMO3 (M = Ta, Nb) compounds for optoelectronic devices.

The electronic, mechanical, optical and thermoelectric properties of Cesium based perovskites CsMO3 (M = Nb, Ta) in the cubic phase has been performed through PBEsol-mBJ scheme in the framework of DFT. The electronic band structures and density of states show the studied materials having a direct band gap in the visible range. The mechanical stability and ductile behavior have been analyzed from elastic constants. Moreover, the optical behavior of the studied materials has been analyzed in terms of dielectric functions, refractive index, extinction coefficient, absorption coefficient, optical conductivity, reflectivity and energy loss factor. Finally, the material response with temperature has been elaborated by electrical conductivity, thermal conductivity, Seebeck coefficient, power factor, heat capacity, Hall coefficient, susceptibility and electron density by using BoltzTraP code. This first principle calculation of optical and thermoelectric properties of the novel compounds provides a new route to the experimentalist for the potential application in energy renewable devices.

Formulation and hypoglycemic activity of pioglitazone-cyclodextrin inclusion complexes.

Pioglitazone is a thiazolidinedione derivative used for the treatment of type 2 diabetes. The drug's poor aqueous solubility and slow dissolution rate are the main causes of its limited therapeutic action in some cases. The aim of the present study is to formulate a more soluble product of pioglitazone at physiological pH. The potential interaction of pioglitazone with cyclodextrins and water-soluble polymers was investigated to enhance the drug's bioavailability and improve its efficacy. The interaction of pioglitazone with ß-cyclodextrin, HP-ß-cyclodextrin, and dimethyl-ß- cyclodextrin was evaluated by spectrophotometric and solubility methods. Both methods revealed the formation of 1:1 inclusion complexes. The phase solubility diagram of pioglitazone-cyclodextrin systems with or without water-soluble polymers was classified as the AL type. The solubilization strength of cyclodextrins and the apparent stability constant of systems increased upon addition of water-soluble polymers. Inclusion complexes of pioglitazone in cyclodextrins with or without watersoluble polymers were prepared by the kneading method. Binary systems were characterized and confirmed by IR spectroscopy, X-ray diffractometry, and thermogravimetric analysis. The dissolution rates of pioglitazone, pioglitazone-cyclodextrin physical mixtures, pioglitazone-cyclodextrin complexes, and ternary systems containing watersoluble polymers were determined using a USP dissolution tester; results revealed enhanced dissolution properties of cyclodextrin complexes compared to drug and physical mixtures, and all of the ternary systems displayed higher dissolution efficiency than corresponding binary systems. The permeation of pioglitazone and pioglitazonecyclodextrin complexes through a cellulose membrane with and without water-soluble polymers (PVP and HPMC) present increased and the release pattern follows the kinetics of a Higuchi equation. Assessment of the hypoglycemic effect of the free drug and its cyclodextrin complexes in normal rats via measurement of blood glucose levels (BGL) after administration of a single oral dose revealed that the hypoglycemic effect of pioglitazone-cyclodextrin complexes was greater than that of the free drug and that a pioglitazone-DM ß-cyclodextrin complex had the greatest effect. In conclusion, the physicochemical and biological properties of pioglitazone improved as a result of complexation with cyclodextrins, and the improvement of physicochemical properties was more prominent after water-soluble polymers were associated with pioglitazone-cyclodextrin systems.

Nanosuspension as an ophthalmic delivery system for certain glucocorticoid drugs.

Poorly-water-soluble compounds are difficult to develop as drug products using conventional formulation techniques. The use of nanotechnology to formulate poorly-water-soluble drugs as nanosuspensions offers the opportunity to address many of the deficiencies associated with this class of molecules. In the present study, the high pressure homogenization method used to prepare nanosuspensions of three practically insoluble glucocorticoid drugs; hydrocortisone, prednisolone and dexamethasone. The effect of particle size in the micron and nano-size ranges as well as the effect of viscosity of the nanosuspension on the ocular bioavailability was studied by measuring the intraocular pressure of normotensive Albino rabbits using shiØetz tonometer. The results show that compared to solution and micro-crystalline suspensions it is a common feature of the three drugs that the nanosuspensions always enhance the rate and extent of ophthalmic drug absorption as well as the intensity of drug action. In the majority of cases nanosuspensions extend the duration of drug effect to a significant extent. The data presented confirms that nanosuspensions differ from micro-crystalline suspensions and solution as ophthalmic drug delivery systems and that the differences are statistically, highly to very highly significant. The results confirm also the importance of viscosity of nanosuspension especially in increasing the duration of drug action.

Free versus liposome-encapsulated lignocaine hydrochloride topical applications.

The influence of encapsulating lignocaine hydrochloride, in a liposomal delivery system on its release from a topical formulation was studied. Liposomes were prepared from a mixture of L-alpha-dipalmitoylphosphatidyl choline (DPPC) and cholesterol in different molar ratios with or without charge inducing agents. The swelling time affording maximum entrapment was tested from 0-48 h at 53 degrees C. The percentage of drug entrapped in liposomes was found to be charge dependent and more pronounced for negatively charged liposomes. The amount of drug entrapped increased by increasing the ratio of cholesterol. The selected formulations were evaluated in vivo using the pin prick method. The results revealed localized and prolonged activity of lignocaine contained in liposomes when compared with an equivalent conventional topical application.

Cyclodextrins in acetazolamide eye drop formulations.

The interaction of acetazolamide with beta-cyclodextrin, (beta-CD), dimethyl-beta-cyclodextrin (DM-beta-CD) and trimethyl-beta-cyclodextrin (TM-beta-CD) was monitored spectrophotometrically. The results revealed formation of equimolar complexes. The apparent solubility of acetazolamide in water was found to increase linearly with increasing CD concentration. The effect of CDs on the permeation of acetazolamide through semi-permeable membranes and the topical delivery of acetazolamide was investigated. Maximum acetazolamide penetration was obtained when just enough CD was used to keep all acetazolamide in solution. For an acetazolamide concentration of 10 mg/ml, the optimum CD concentration appeared to be 3.5 mmol/l for beta-CD, 2.8 mmol/l for TM-beta-CD and 6.0 mmol/l for DM-beta-CD. The effect of CDs on the bioavailability of acetazolamide was assessed by measuring the intraocular pressure in rabbits. The results indicated that CDs have a significant influence on the biological performance of the drug leading to augmentation in its intensity of action and bioavailability as well as prolongation in its duration of action.

CT appearance of direct leukemic invasion of bowel.

Although leukemic invasion of bowel is frequently seen on pathologic examination, it has rarely been described in the imaging literature. Previous radiographic reports have relied mostly on non-cross-sectional imaging techniques such as barium enema and have detected abnormalities only in the most advanced stages of disease when prognosis is uniformly poor. We describe a case of direct leukemic invasion seen on computed tomography which may offer the advantage of earlier detection and more favorable prognosis.

Common carotid artery: variability of Doppler US velocity measurements.

PURPOSE: To determine if Doppler ultrasound (US) measurements of systolic velocity in the common carotid artery vary markedly with distance from the bifurcation. MATERIALS AND METHODS: Bilateral, insonation angle-corrected velocity was measured with US in the common carotid artery. Measurements were obtained 1, 2, 3, 4, and 5 cm from the carotid artery bifurcation in 20 volunteers (aged 25-43 years) with no history of neurologic or cardiovascular disease. RESULTS: Velocity in the common carotid artery increased with distance (toward the aorta) from the bifurcation (mean increase, 9 cm/sec for each centimeter of distance from the bifurcation, up to the 4-cm distance; P < .001). Velocity increased more rapidly in subjects who were younger (P < .001) and in those with a lower pulse rate (P = .001). CONCLUSION: The distance from the bifurcation at which common carotid artery velocity is measured should be standardized. This may increase the accuracy of the systolic velocity ratio for assessment of internal carotid artery stenosis and decrease some of the reported variability between different centers that perform US of the carotid artery.

Schistosoma mansoni infection in mice augments the capacity for interleukin 3 (IL-3) and IL-9 production and concurrently enlarges progenitor pools for mast cells and granulocytes-macrophages.

Mast cells and granulocytes-macrophages (GM) are components of the host defense system against worm infections, including schistosomiasis. Here we report the kinetics of changes in the number of colony-forming cells (CFC) for mast cells and GM during the course of a primary experimental infection of mice with Schistosoma mansoni cercariae over a period of 24 weeks postinfection (p.i.). Concurrently, we measured known myelopoietic and/or mast cell-stimulating cytokines (i.e., interleukin 3 [IL-3] and IL-9) in pokeweed mitogen-activated spleen cell-conditioned medium. Our results show that during the acute phase of the hepatic granulomatous reaction, the numbers of both mast-CFC and GM-CFC were significantly elevated in bone marrow. However, while femoral GM-CFC numbers had returned to normal control values at week 16 p.i., femoral and splenic mast-CFC numbers remained significantly elevated until week 20 p.i., which corresponds to the chronic fibrotic phase of hepatic granulomatous inflammation. Increased GM-CFC numbers correlated with elevated IL-3 levels, while increased mast-CFC numbers paralleled the increased IL-9 concentrations in spleen cell-conditioned medium. By the reverse transcription-PCR method, enhanced expression of IL-3 and IL-9 transcripts was found in RNA samples obtained from livers and spleens of infected mice. Our data demonstrate that during the course of infection of mice with S. mansoni, the coordinate need for mast cells and GM is at least partly regulated at the stage of progenitor cell commitment in the bone marrow and spleen. It appears that IL-3 and IL-9 help to promote at this stage the ultimate generation of mature effector cells.

Interaction of ibuprofen and indomethacin with caffeine.

The potentiality of interaction of ibuprofen and indomethacin with caffeine was investigated by UV and IR spectrophotometry. Differential UV spectrophotometry revealed a decrease in optical intensity of the two drugs in presence of caffeine as well as a bathochromic shift in the delta max of ibuprofen. On the other hand, IR spectrophotometry confirmed such an interaction as evidenced by a marked change in the spectra of the two drugs in presence of caffeine. The stoichiometry of interaction of the two drugs with caffeine was determined and found to be 2:1. The stability constants of the complexes were determined and the complex of ibuprofen was found to be more stable. The complexes were prepared by the kneading method and the implication of interaction on certain pharmaceutical properties of the two drugs was monitored. These included apparent solubility in water, dissolution rate, stability, partitioning properties as well as dermal diffusion. The results depicted an increase in the apparent solubility of the two drugs in water, enhancement in their dissolution properties, increase in stability, decrease in their partition coefficients between phosphate buffer (pH = 5.5) and n-octanol as well as decrease in their release rate constants through abdominal rat skin. The latter result would point out to the limitation of using these complexes in transdermal systems.

Kinetics of interleukin-6 production after experimental infection of mice with Schistosoma mansoni.

It has been reported that interleukin-6 (IL-6) is expressed in cells of acute inflammatory granulomas experimentally induced in mice by eggs of Schistosoma mansoni. Moreover, in vitro IL-6 was shown to enhance the cytotoxic activity of human platelets against larvae of S. mansoni. To elucidate further a proposed biological significance of this cytokine during the course of schistosomiasis, we studied the kinetics of IL-6 production and concomitantly performed a histopathological analysis of the livers in BALB/c mice subcutaneously infected with S. mansoni cercariae. Over a period of 24 weeks postinfection (p.i.) we monitored serum IL-6 levels, IL-6 production in vitro by pokeweed mitogen (PWM)-stimulated spleen cells as well as IL-6 mRNA expression in livers, spleens and kidneys. We found significantly elevated IL-6 levels in PWM-stimulated spleen cell-conditioned media (SCM) at weeks 6 to 20 p.i., peaking at week 10 p.i. In contrast, serum IL-6 concentrations started to rise not before week 8 but remained significantly elevated above normal control values until week 24 p.i. The time pattern of enhanced IL-6 mRNA expression detected in spleens and livers, but not in kidneys, as well as the rises of IL-6 in SCM and with a delay of 2 weeks in serum samples correlated with the onset of the egg-induced inflammatory reactions as well as the incidence and the number of the granulomas observed histopathologically in the livers of infected mice. Our data emphasize both a local and a systemic role of IL-6 in the host immune response following infection of mice with S. mansoni.

Discrepancy among dissolution rates of commercial tablets as a function of dissolution method. part 6: rifampicin.

The dissolution rate of six batches of commercial rifampicin products manufactured by three pharmaceutical companies was determined by both closed and open dissolution systems. The most consistent results were those obtained by the beaker method. Inter-batch as well as inter-brand variation in dissolution were found to be more evidently detected and evaluated by adopting the beaker and flow-through methods. The biovailability of these products was assessed in human subjects according to a cross-over design system. Based on the values of the correlation coefficient of the in vitro results obtained by different dissolution methods with the in vivo results, the USP rotating basket method appears to correlate best with maximum urinary excretion rate, area under excretion rate versus time curve as well as total amount of drug excreted. Thus, determination of the dissolution rate of rifampicin products by the USP rotating basket method can be considered as a reliable tool for predicting the in vivo performance of the drug.