Saturated System Research Articles

Solid super saturated self-nanoemulsifying drug delivery system (sat-SNEDDS) as a promising alternative to conventional SNEDDS for improvement rosuvastatin calcium oral bioavailability

ABSTRACTObjective: This study aims to illustrate the applicability of solid supersaturated self-nanoemulsifying drug delivery system (sat-SNEDDS) for the improvement of rosuvastatin calcium (RC) oral bioavailability.Methods: Different sat-SNEDDS were prepared by incorporating different ratios of RC into SNEDDS using tween80/PEG400 (77.2%) as surfactant/cosurfactant mixture and garlic /olive oil (22.8%) as oil phase. The prepared systems were characterized viz; size, zeta potential, TEM and stability. Various hydrophilic and hydrophobic carriers were employed to solidify the optimized RC sat-SNEDDS. The influence of the carrier was investigated by SEM, XRPD, DSC, flow properties, in vitro precipitation, drug release and oral bioavailability study.Results: The adsorption of the stable positively charged nanocarrier RC sat-SNEDDS onto solid carriers provided free flowing amorphous powder. The carrier could amend the morphological architecture and in vitro release of the RC solid sat-SNEDDS. Hydrophobic carriers as microcrystalline cellulose 102 (MCC) showed superior physical characters and higher dissolution rate over hydrophilic carriers as maltodextrin with respective T100% 30 min and 45 min. The rapid spontaneous emulsification, the positively nanosized MCC-sat-SNEDDS improved oral bioavailability of RC by 2.1-fold over commercial tablets.Conclusion: Solid MCC-sat-SNEDDS combined dual benefits of sat-SNEDDS and solid dosage form was successfully optimized to improve RC oral bioavailability.

On the focal subgroup of a saturated fusion system

The influence of the cyclic subgroups of order p or 4 of the focal subgroup of a saturated fusion system F over a p-group S is investigated in this paper. Some criteria for normality of S in F as well as necessary and sufficient conditions for nilpotency of F are given. The resistance of a p-group in which every cyclic subgroup of order p or 4 is normal, and earlier results about p-nilpotence of finite groups and nilpotency of saturated fusion systems are consequences of our study.

Environmentally relevant organophosphate triesters in herring gulls: In vitro biotransformation and kinetics and diester metabolite formation using a hepatic microsomal assay

The in vitro biotransformation and kinetics of six organophosphate triester (OPE) flame retardants were investigated in herring gulls (Larus argentatus) from the Great Lakes using a hepatic microsomal metabolism assay. Administration of each individual OPE (tri-n-butyl phosphate (TNBP), tris(2-butoxyethyl) phosphate (TBOEP), triphenyl phosphate (TPHP), triethyl phosphate (TEP), tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and tris(2-chloroisopropyl) phosphate (TCIPP)) to the in vitro assay (concentration range 0.01 to 10μM) resulted in rapid depletion with the exception of TEP. Following the Michaelis-Menten enzyme kinetics model, a preliminary 2-minute incubation period was used to estimate the Vmax (±SE) values (i.e., the maximal rate of reaction for a saturated enzyme system), which ranged from 5.0±0.4 (TPHP) to 29±18pmol/min/mg protein (TBOEP), as well as the KM (±SE) values (i.e., the OPE concentration corresponding to one half of the Vmax), which ranged from 9.8±1 (TPHP) to 189±135nM (TBOEP). Biotransformation assays over a 100-minute incubation period revealed that TNBP was metabolized most rapidly (with a depletion rate of 73±4pmol/min/mg protein), followed by TBOEP (53±8pmol/min/mg), TCIPP (27±1pmol/min/mg), TPHP (22±2pmol/min/mg) and TDCIPP (8±1pmol/min/mg). In vitro biotransformation of OP triesters was clearly structure-dependent where non-halogenated alkyl OP triesters were metabolized more rapidly than halogenated alkyl triesters. Halogenated OP triesters were transformed to their respective diesters more efficiently relative to non-halogenated OP triesters. To our knowledge, this is the first study to investigate OP triester metabolism and OP diester formation in an avian or wildlife model system, which is important to understand the fate and biological activity of OPEs in an exposed organism.

Structure and Properties of 9,14,15,16,17,18,19,20-Octahydro-9,14[1′,4′]-benzenobenzo[b]triphenylene

The compound 9,14,15,16,17,18,19,20-octahydro-9,14[1′,4′]-benzenobenzo[b]triphenylene, C28H24, was prepared by hydrogenation of the 4πs+4πs photocycloadduct of dibenz[a,c]anthracene and 1,3-cyclohexadiene with Pt/C in ethyl acetate. The X-ray diffraction analysis shows that the compound crystallizes in the monoclinic space group P21/c with the geometric parameters of a = 11.0090(17) Å, b = 13.733(2) Å, c = 13.091(2) Å, and β = 109.583(13)°. In addition to several close intramolecular contacts involving hydrogens derived from the dibenzanthracene moiety, long interannular C–C single bonds of about 1.593 Å are present. These bonds are shorter by about 0.18 Å than the corresponding bonds in the unsaturated precursor, which can be attributed to reduced strain in the more saturated polycyclic ring system. Anisotropic shielding of the four endo-methylene hydrogens in the 1H NMR spectrum is larger for the two hydrogens lying above the phenanthrene unit, which resonate at 1.03 ppm, than those above the benzenoid ring, which resonate at 1.24 ppm. Theoretical calculations reproduce the geometry with good agreement.

Patients with gout differ from healthy subjects in renal response to changes in serum uric acid

ObjectiveOur objectives were to determine whether a change in serum uric acid (sUA) resulted in a corresponding change in the fractional excretion of uric acid (FEUA) and whether the renal response was different in patients with gout versus healthy subjects. MethodsFEUA was calculated from previously published studies and four new phase I studies in healthy subjects and/or patients with gout before and after treatment to lower or raise sUA. Treatments included xanthine oxidase inhibitors to lower sUA as well as infusion of uric acid and provision of a high-purine diet to raise sUA. Plots were created of FEUA versus sUA before and after treatment. For the phase I studies, percent change in FEUA per mg/dL change in sUA was calculated separately for healthy subjects and patients with gout, and compared using Student's t test. ResultsAnalysis of previously published data and the new phase I clinical data indicates that changing sUA by a non-renal mechanism leads to a change in FEUA. The magnitude of change is greater in subjects with higher baseline FEUA versus patients with gout. Healthy subjects excrete more urate than do patients with gout at physiological urate-filtered load; this difference disappears when the urate-filtered load is decreased to ∼5000mg/24hours. ConclusionThese observations are consistent with a less saturated urate reabsorption system in patients with gout versus healthy subjects, resulting in elevated retention of uric acid. Further investigation could lead to the discovery of mechanisms responsible for the etiology of hyperuricemia/gout.

Numerical Modeling on Benzene Dissolution into Groundwater and Transport of Dissolved Benzene in a Saturated Fracture-Matrix System

Dissolution from residual source zones of benzene poses serious threat to the groundwater quality. Proper understanding of fate and migration of dissolved benzene is a prerequisite for planning remediation strategies to reduce groundwater contamination. In the present study, an attempt has been made to numerically model the dissolution of benzene and to investigate the transport of aqueous phase benzene in a saturated fracture-matrix system under steady-state flow condition. In addition to dissolution mass transfer, advection, dispersion and matrix diffusion of aqueous benzene has been considered along the fracture. In the present numerical model, residual phase benzene is considered to be present along the entire length of the fracture and residual phase benzene is assumed to be immobile for the flow conditions considered in the analysis. Transport equations for fracture and rock-matrix are solved using implicit finite difference method. Transport equation for aqueous benzene within the fracture has been solved in a one-dimensional domain and transport equation for aqueous benzene within rock-matrix has been solved in a pseudo-two-dimensional domain. Sensitivity studies have been conducted to investigate the impact of variation of flow velocity, dispersivity, fracture aperture, inlet benzene concentration, rock-matrix diffusion coefficient, and half fracture spacing on transport of aqueous benzene concentration within the fracture. From the present study, it can be concluded that the addition of slow liquid benzene dissolution into aqueous phase influences the benzene breakthrough curves/profiles at different velocity, fracture aperture, initial benzene concentration, mass transfer rate, rock dispersivity and half fracture spacing.

Maternal Obesity Programs Offspring Muscle Mitochondrial Function

A high-fat (HF) diet induces metabolic disease while initially increasing muscle mitochondrial content: a putative compensatory response to increased reactive oxygen species (ROS). Maternal obesity exacerbates the metabolic syndrome phenotype in offspring weaned to a HF diet, but little is known about the effects of maternal obesity on muscle mitochondrial function. PURPOSE: To determine whether maternal obesity influences muscle mitochondrial function in offspring weaned to a HF diet. METHODS: Female mice were fed a control (CON, 10% kcal) or HF (45% kcal) diet to induce maternal obesity prior to mating. Diets were maintained throughout pregnancy and lactation. Male offspring (n=30) were weaned to HF or CON diet creating 4 groups (CON/CON, CON/HF, HF/CON, HF/HF). At 12 months body composition (DEXA) and mitochondrial function in permeabilized gastrocnemius bundles (high-resolution respirometry) was determined. RESULTS: Newborns and adult offspring of obese dams were heavier than CON. Percent lean body mass was lower in offspring of obese mice, and those weaned to a HF diet (71±2, 52±2, 60±2, 50±1 % in the 4 groups respectively; effect of maternal obesity and HF diet p<0.05, two-way ANOVA). Maximal muscle fatty-acid (palmitoyl+carnitine, PC) and carbohydrate (glutamate) driven respiration with saturating ADP, oxidative phosphorylation (OXPHOS) and electron transport system capacity (ETS) were each greater in HF diet (p<0.05). Flux control ratio for ADP+PC was also greater in HF diet (0.15±0.05, 0.25±0.06, 0.16±0.04, 0.23±0.05, p<0.05). OXPHOS capacity tended to be lower in offspring of obese dams (64±16, 82±21 vs. 56±16, 72±12 pmol/s/mg, effect of maternal obesity p=0.2) and was accompanied by a greater LEAK respiration (5.7±3.1, 7.5±2.1 vs. 8.0±2.3, 8.7±3.8 pmol/s/mg, effect of maternal obesity p=0.06). CONCLUSIONS: Greater LEAK in offspring of obese dams indicates pathologically dyscoupled respiration, perhaps consequent to increased ROS. Despite this, muscle oxidative capacity tended to be lower in the muscles of offspring of obese dams. Maternal obesity may contribute to HF-diet associated metabolic disease by ameliorating the compensatory increase in muscle mitochondrial content and function. Support: March of Dimes 030344; Pulmonary Education and Research Foundation.

Experimental temperature cycling as a powerful tool to enlarge melt pools and crystals at magma storage conditions

Experiments in high silica systems at temperatures close to the solidus often produce crystals and melt pools that are too small for in situ analysis. Oscillating the temperature during an experimental run speeds up recrystallization of magma by dissolving small and increasing the size of larger crystals, dramatically changing the crystal size distribution. This principle of periodic heating and cooling, caused for example by repeated injection of hot magma, is also a potential acceleration for the formation of phenocrystic textures in natural rocks. Here we show that temperature cycling has the potential to significantly enlarge melt pools and crystals in a fluid saturated dacitic system. Using a natural dacite dredged from the Pacific-Antarctic Rise as starting material, we performed crystallization experiments applying temperature cycling systematically for two different temperatures and different water activities at 200 MPa. For experiments at 950 °C (with a H2O ~1, ~0.3, and <0.1) an internally heated pressure vessel was used, experiments at 800 °C (with a H2O ~1, ~0.5) were performed in a cold-seal pressure vessel. Comparative experiments at equilibrium conditions with constant temperature were performed for both approaches. For all other experiments temperature was cycled with amplitudes of 20 K for different time intervals but constant total run duration after initial equilibration at constant temperature. Additionally, for one experiment at 800 °C, the temperature was increased several times by 50 K to study the potential of dissolving tiny crystals in the matrix. As a result of the temperature cycling, tiny crystals in the matrix were preferentially dissolved, leading to large melt pools with only rare mineral inclusions enabling microprobe analysis using a defocused beam. With regard to the area of the 10 largest crystals of each cycling experiment, clinopyroxene crystals were up to 19 times larger, and plagioclase crystals even up to 69 times when comparing to experiments performed at constant temperature. Grain sizes of FeTi-oxide phases are less influenced by this technique. Essential requirements for applying temperature cycling routinely are identical phase relations and compositions in runs with constant and cycled temperature. For all studied temperatures and water activities, the phase assemblage was the same and compositions of all phases are identical within the analytical error. Thus, the temperature cycling technique opens interesting perspectives, especially in facilitating in situ analysis in near solidus systems.

Superconducting Nanowire Single-Photon Detector With a System Detection Efficiency Over 80% at 940-nm Wavelength

Implementations of quantum information require single-photon detectors (SPDs) with high detection efficiency (DE) at a wavelength of 940 nm, which is a challenge for the available semiconducting SPDs. Superconducting nanowire SPDs (SNSPDs) are capable of detecting visible and near-infrared single photons with high DE. However, these detection capabilities place stringent design requirements on the cavity and nanowire geometry structures. We design, fabricate, and measure SNSPDs with high DE optimized for the 940-nm wavelength. The NbN SNSPDs were fabricated on 1-D photonic crystals for high optical absorptance. By tuning the filling factor of the nanowire through numerical simulations and experiments, we were able to obtain an SNSPD (7 nm thick, 125 nm width, and 0.57 filling factor, as well as active area of 18 * 18 μm) with a saturated system DE of 83.6 ± 3.7%, at a dark count rate of 10 Hz, and a low polarization dependence of 1.17 ± 0.02. To our best knowledge, this is the highest value reported for NbN SNSPDs at 940-nm wavelength. The availability of an SNSPD with high system DE at 940 nm may have a profound impact in the field of photonic quantum technologies, such as multiphoton entanglement.

Control of fixed points and existence and uniqueness of centric linking systems

A. Chermak has recently proved that to each saturated fusion system over a finite $p$-group, there is a unique associated centric linking system. B. Oliver extended Chermak's proof by showing that all the higher cohomological obstruction groups relevant to unique existence of centric linking systems vanish. Both proofs indirectly assume the classification of finite simple groups. We show how to remove this assumption, thereby giving a classification-free proof of the Martino-Priddy conjecture concerning the $p$-completed classifying spaces of finite groups. Our main tool is a 1971 result of the first author on control of fixed points by $p$-local subgroups. This result is directly applicable for odd primes, and we show how a slight variation of it allows applications for $p=2$ in the presence of offenders.

Real-Time Reachability for Verified Simplex Design

The Simplex architecture ensures the safe use of an unverifiable complex/smart controller by using it in conjunction with a verified safety controller and verified supervisory controller (switching logic). This architecture enables the safe use of smart, high-performance, untrusted, and complex control algorithms to enable autonomy without requiring the smart controllers to be formally verified or certified. Simplex incorporates a supervisory controller that will take over control from the unverified complex/smart controller if it misbehaves and use a safety controller. The supervisory controller should (1) guarantee that the system never enters an unsafe state (safety), but should also (2) use the complex/smart controller as much as possible (minimize conservatism). The problem of precisely and correctly defining the switching logic of the supervisory controller has previously been considered either using a control-theoretic optimization approach or through an offline hybrid-systems reachability computation. In this work, we show that a combined online/offline approach that uses aspects of the two earlier methods, along with a real-time reachability computation, also maintains safety, but with significantly less conservatism, allowing the complex controller to be used more frequently. We demonstrate the advantages of this unified approach on a saturated inverted pendulum system, in which the verifiable region of attraction is over twice as large compared to the earlier approach. Additionally, to validate the claims that the real-time reachability approach may be implemented on embedded platforms, we have ported and conducted embedded hardware studies using both ARM processors and Atmel AVR microcontrollers. This is the first ever demonstration of a hybrid-systems reachability computation in real time on actual embedded platforms, which required addressing significant technical challenges.

29Si nuclear spin relaxation in microcrystals of plastically deformed Si: B samples

Single crystals and microcrystals Si: B enriched with 29Si isotopes have been studied using nuclear magnetic resonance and electron paramagnetic resonance (EPR) in the temperature range from 300 to 800 K. It has been found that an increase in the temperature from 300 to 500 K leads to a change in the kinetics of the relaxation of the saturated nuclear spin system. At 300 K, the relaxation kinetics corresponds to direct electron–nuclear interaction with inhomogeneously distributed paramagnetic centers introduced by the plastic deformation of the crystals. At 500 K, the spin relaxation occurs through the nuclear spin diffusion and electron–nuclear interaction with an acceptor impurity. It has been revealed that the plastic deformation affects the EPR spectra at 9 K.

Variable speed wind turbine control by discrete-time sliding mode approach

The aim of this paper is to propose a new design variable speed wind turbine control by discrete-time sliding mode approach. This methodology is designed for linear saturated system. The saturation constraint is reported on inputs vector. To this end, the back stepping design procedure is followed to construct a suitable sliding manifold that guarantees the attainment of a stabilization control objective. It is well known that the mechanisms are investigated in term of the most proposed assumptions to deal with the damping, shaft stiffness and inertia effect of the gear. The objectives are to synthesize robust controllers that maximize the energy extracted from wind, while reducing mechanical loads and rotor speed tracking combined with an electromagnetic torque. Simulation results of the proposed scheme are presented.

A Bijective Map on Normal Fusion Subsystems

Let ℱ be a saturated fusion system over a finite p-group S, and let Z ≤ Zn (ℱ), which is strongly closed in S with respect to ℱ. In this paper, we prove that there is a natural bijection from the set of normal subsystems of ℱ containing Z to the set of normal subsystems of the factor system ℱ+ = ℱ/Z. This generalizes a result of Aschbacher.

The theory of injection of liquid carbon dioxide in formation, saturated system “hydrate of methane–methane” in the mode of formation of the intermediate melt zone

The scheme and the corresponding theoretical model of process of methane replacement by liquid carbon dioxide at his injection in a gas hydrate layer are offered. The flat one-dimensional automodel solution corresponding to injection of carbon dioxide in semi-infinite layer through flat border is constructed. It is fixed that such solution can contain three characteristic zones in general case: the far zone, where there is a methane filtration in the porous medium which is partially saturated by methane hydrate in the absence of phase transitions; the melted zone of products of decomposition of methane hydrate (water and methane) can be formed in the intermediate zone (this zone is formed because of heating owing to injection of warm carbon dioxide); the near zone where there is a filtration of liquid carbon dioxide in the layer which is partially saturated by hydrate of carbon dioxide. The analysis of influence of parameters of layer, his initial state (temperature, pressure and hydrate saturation) and the parameters of the injected dioxide of carbon on the various modes of filtration is conducted.

Effect of Temperature and Pressure on the Bulk Modulus of a Poroelastic System

Pressure and temperature are ubiquitous physical parameters that affect subsurface porous systems both under ambient geologic conditions and under engineering operations related to fluid injection and thermal operations. Consequently, for efficient planning of subsurface operations, trends in elastic parameter variations with temperature and pressure need to be understood. In the petroleum literature, measurements have been made on the effect of temperature and pressure on bulk modulus of saturated porous systems. Reported experimental results predict interesting and definite trends. In this paper, the effect of pressure and temperature on the bulk modulus of the saturated porous system under undrained conditions, mostly applicable to low permeability environments has been mathematically, investigated. The equation presented has been found to predict experimental observations under different combinations of pressure and temperature as found in published works. Also, the model predicts higher bulk moduli for poroelastic systems with lower initial porosities for a given set of temperature and pressure conditions and this has been substantiated using literature source experimental data. By using this model, the combined effect of temperature and pressure on bulk moduli of igneous and sedimentary rocks can be compared analytically.

Phase equilibria study of Cu–O–ZnO system in various oxygen partial pressures

Phase relationships of the Cu–O–ZnO system in equilibrium with air (PO2=0.21atm) and metallic copper (in pure argon) have been studied for the first time using equilibration/quenching/EPMA techniques. In this study, we quantified the phases in equilibrium with air in the temperature range 1095–1500°C and represented the equilibria by the pseudo-binary phase diagram (Cu2O–ZnO). The diagram has one simple eutectic reaction with two primary phases of cuprite (Cu2O) and zincite (ZnO), and the binary eutectic point was found to be 1098±2°C with 0.10±0.01mol fraction of ZnO. There were three phases Cu2O+ZnO+liquid copper or ZnO (Cu2O)+liquid oxide+liquid copper coexisting with each other in the temperature range 1205–1300°C, when the system was equilibrated with metallic copper. Isothermal ternary phase diagrams (Cu–O–ZnO) were used to present the results of the experiments at Cu saturation. The eutectic point of the Cu saturated system was determined to be 1208±2°C and 0.03±0.01mol fraction of ZnO. Results were compared with the phase diagrams calculated by MTDATA 5.10 and its Mtox 7.0 database. The differences between the experimental data and the computational phase boundaries were significant and the system properties require a re-assessment.

The abelian monoid of fusion-stable finite sets is free

We show that the abelian monoid of isomorphism classes of G-stable finite S-sets is free for a finite group G with Sylow p-subgroup S; here a finite S-set is called G-stable if it has isomorphic restrictions to G-conjugate subgroups of S. These G-stable S-sets are of interest, e.g., in homotopy theory. We prove freeness by constructing an explicit (but somewhat nonobvious) basis, whose elements are in one-to-one correspondence with the G-conjugacy classes of subgroups in S. As a central tool of independent interest, we give a detailed description of the embedding of the Burnside ring for a saturated fusion system into its associated ghost ring.

Transfer and characteristic idempotents for saturated fusion systems

We construct a well-behaved transfer map from the p-local Burnside ring of the underlying p-group S to the p-local Burnside ring of a saturated fusion system F. Using this transfer map, we give new results on the characteristic idempotent of F – the unique idempotent in the p-local double Burnside ring of S satisfying properties of Linckelmann and Webb. We describe this idempotent explicitly both in terms of fixed points and as a linear combination of transitive bisets. Additionally, using fixed points we determine the map for Burnside rings given by multiplication with the characteristic idempotent, and show that this is the transfer map previously constructed. Applying these results, we show that for every saturated fusion system the ring generated by all (not necessarily idempotent) characteristic elements in the p-local double Burnside ring is isomorphic as rings to the p-local “single” Burnside ring of the fusion system, and we disprove a conjecture by Park–Ragnarsson–Stancu on the composition product of fusion systems.

Stabilization of a class of nonlinear systems with actuator saturation via active disturbance rejection control

The stabilization problem of a class of nonlinear systems with actuator saturation is investigated via active disturbance rejection control (ADRC). We first present results for systems with nonlinear ADRC and show that local stabilization can be achieved in a region including the origin. Then, for the linear ADRC, the linear matrix inequality (LMI) conditions for determining the estimate of the domain of attraction of the resulting closed-loop system are formulated based on a quadratic candidate Lyapunov function and a generalized sector condition. An LMI-based algorithm is correspondingly established to design the linear ADRC controller. The obtained results suggest a new way to stabilize the saturated nonlinear system, even in the case that the state of the system is not fully available for measurement and system nonlinear dynamics are largely unknown. An illustrative example validates the effectiveness of the proposed approach.