Nonlinear Vibrations and Chaos in Rectangular Functionally Graded Plates with Thermo-mechanical Coupling

We analyze the nonlinear dynamics of a simply supported, rectangular, and functionally graded plate in terms of a newly derived coupled system of thermo-elasticity and energy equations, which is then expanded here in derivations and explored for chaotic responses through a parameter study in the state space. The plate properties vary linearly in thickness. Three-dimensional stress-strain relations are considered in general case and nonlinear strain-displacement relations are deployed to account for the plate’s large deflection. A lateral harmonic force is applied on the plate, and there is a heat generation source within it and the surfaces are exposed to free convection. By integrating over the thickness, four new thermal parameters are introduced, which together with the midplane displacements constitute a system of seven partial differential equations. These equations are changed into ordinary differential equations in time using Galerkin’s approximation and solved by using the 4th order RungeKutta method. Finally, a parameter study is performed and the appropriate conditions resulting in chaotic solutions are determined by using numerical features such as the Lyapunov exponent and power spectrum

Controlled Release Formulation of Indomethacin Prepared With Bee Glue Extracts

Purpose: To prepare and evaluate new sustained release formulations of indomethacin based on extracts of propolis (bee glue).Methods: Standardization of propolis (bee glue) extracts was performed by high performance liquid chromatography (HPLC) and determination of the values of fat and fixed oils. Several indomethacin capsule formulations (F1 - F18) containing varying amounts of chloroform (0.75 - 75 mg) and ethanol extracts (30 - 75 mg) of propolis were prepared. The dissolution rate of the formulations was evaluated by USP dissolution (rotating basket) method I and the release data subjected to various kinetic models. Probable interaction between the drug and propolis extracts was studied by differential scanning calorimetry (DSC).Results: The results show that, although the release rate of formulations F1 - F7 did not show any significant difference (p < 0.05) compared to F18 as blank, the other formulations did. DSC results indicate that incorporation of propolis extract in the formulations lowered indomethacin melting point by between 5 and 30 ºC, indicating interaction between the drug and the waxy extract. Kinetic analysis of the in vitro release data of the formulations showed that the best-fit drug release model varied with the drug:propolis extract ratio of the formulations.Conclusion: Formulation F13 (with equal proportion of drug and bee glue extract) came out best from the dissolution test for indomethacin extended-release capsules as it exhibited zero order kinetics. This fpormulation is therefore suitable for further development as a matrix formulation for controlled release.Keywords: Propolis (bee glue), Indomethacin, Controlled release, Zero order kinetics, Waxy material

Excitation of the Earth's Chandler wobble by a turbulent oceanic double-gyre

We develop a layer-averaged, multiple-scale spectral ocean model and show how an oceanic double-gyre can communicate with the Earth's Chandler wobble. The overall transfers of energy and angular momentum from the double-gyre to the Chandler wobble are used to calibrate the turbulence parameters of the layer-averaged model. Our model is tested against a multilayer quasi-geostrophic ocean model in turbulent regime, and base states used in parameter identification are obtained from mesoscale eddy resolving numerical simulations. The Chandler wobble excitation function obtained from the model predicts a small role of North Atlantic ocean region on the wobble dynamics as compared to all oceans, in agreement with the existing observations

Fast spectral solutions of the double-gyre problem in a turbulent flow regime

Several semi-analytical models are considered for a double-gyre problem in a turbulent flow regime for which a reference fully numerical eddy-resolving solution is obtained. The semi-analytical models correspond to solving the depth-averaged Navier–Stokes equations using the spectral Galerkin approach. The robustness of the linear and Smagorinsky eddy-viscosity models for turbulent diffusion approximation is investigated. To capture essential properties of the double-gyre configuration, such as the integral kinetic energy, the integral angular momentum, and the jet mean-flow distribution, an improved semi-analytical model is suggested that is inspired by the idea of scale decomposition between the jet and the surrounding flow

HPLC DETERMINATION OF PARTHENOLIDE AND APIGENIN CONTENTS VERSUS LABEL CLAIMS IN IRANIAN PRODUCTS

In this study parthenolide content of feverfew product (Tanamigraine capsule) and apigenin content of chamomile products (Chamomill drop, Kamisol solution, Prostatan drop, Prostatan tablet) were determined as effective compound by HPLC. Feverfew product was extracted by methanol/distilled de-ionized water (50: 50) and chamomile products by methanol. The HPLC operating conditions were C-18 reversed phase column (VP-ODS 250×4.6 mm, 5 mm), methanol/ distilled de-ionized water (60: 40) as the mobile phase at a flow rate of 1 ml/min and UV detection at 214 nm for parthenolide and 2% acetic acid: acetonitril with linear program 80 to 40 % of acetic acid 2% with a flow rate of 1 ml/min and UV detection at 275nm for apigenin. The amount of parthenolide and apigenin obtained in Tanamigraine capsules and chamomile products is 0.13- 016% and 0.04- 35% respectivel

Groundwater augmentation through the site selection of floodwater spreading using a data mining approach (case study: Mashhad Plain, Iran)

© 2018 by the authors. It is a well-known fact that sustainable development goals are difficult to achieve without a proper water resources management strategy. This study tries to implement some state-of-the-art statistical and data mining models i.e., weights-of-evidence (WoE), boosted regression trees (BRT), and classification and regression tree (CART) to identify suitable areas for artificial recharge through floodwater spreading (FWS). At first, suitable areas for the FWS project were identified in a basin in north-eastern Iran based on the national guidelines and a literature survey. Using the same methodology, an identical number of FWS unsuitable areas were also determined. Afterward, a set of different FWS conditioning factors were selected for modeling FWS suitability. The models were applied using 70% of the suitable and unsuitable locations and validated with the rest of the input data (i.e., 30%). Finally, a receiver operating characteristics (ROC) curve was plotted to compare the produced FWS suitability maps. The findings depicted acceptable performance of the BRT, CART, and WoE for FWS suitability mapping with an area under the ROC curves of 92, 87.5, and 81.6%, respectively. Among the considered variables, transmissivity, distance from rivers, aquifer thickness, and electrical conductivity were determined as the most important contributors in the modeling. FWS suitability maps produced by the proposed method in this study could be used as a guideline for water resource managers to control flood damage and obtain new sources of groundwater. This methodology could be easily replicated to produce FWS suitability maps in other regions with similar hydrogeological conditions

Control Space Reduction and Real-Time Accurate Modeling of Continuum Manipulators Using Ritz and Ritz-Galerkin Methods

To address the challenges with real-time accurate modeling of multi-segment continuum manipulators in the presence of significant external and body loads, we introduce a novel series solution for variable-curvature Cosserat rod static and Lagrangian dynamic method. By combining a modified Lagrange polynomial series solution, based on experimental observations, with Ritz and Ritz-Galerkin methods, the infinite modeling state space of a continuum manipulator is minimized to geometrical position of a handful of physical points (in our case two). As a result, a unified easy to implement vector formalism is proposed for the nonlinear impedance and configuration control. We showed that by considering the mechanical effects of highly elastic axial deformation, the model accuracy is increased up to 6%. The proposed model predicts experimental results with 6-8% (4-6 [mm]) mean error for the Ritz-Galerkin method in static cases and 16-20% (12-14 [mm]) mean error for the Ritz method in dynamic cases, in planar and general 3D motions. Comparing to five different models in the literature, our approximate solution is shown to be more accurate with the smallest possible number of modeling states and suitable for real-time modeling, observation and control applications

Usefulness of nabilone as an antiemetic in persistent vomiting due to refractory gastrointestinal disorders

Nabilone, a synthetic analogue of delta-9-Tetrahydrocannabinol, is an agonist of cannabinoid receptors (CB-1 and CB-2) approved to treat chemotherapy-induced vomiting refractory to antiemetics. Its use in patients with refractory vomiting due to gastrointestinal dysmotility (GID) has not been reported. Our study aims are to assess nabilone usefulness and side-effects in patients with refractory vomiting due to GID. Patients prescribed nabilone at St. Mark's intestinal rehabilitation unit (January 2017 to September 2022) due to GID vomiting have been retrospectively reviewed. Descriptive analysis has been done. Variables measured: age, sex, comorbidities, antiemetics/prokinetics, enteral or parenteral nutrition, nabilone prescription, subjective symptom improvement and side-effects. Seven patients received nabilone. 5/7 (72%) were females. Median age:25 years (23-37). 3/7 (43%) had gastroparesis (1/3 related to postural orthostatic tachycardia syndrome -POTS- , 1/3 to Ehlers-Danlos' Syndrome, POTS, Crohn's Disease and adrenal insufficiency -AI- and 1/3 to sinus node ablation and AI), 2/7 (29%) had gastroparesis and intestinal dysmotility (1/2 related to POTS and 1/2 related to EDS and other connective tissue diseases) and 2/7 (29%) had intestinal dysmotility (1/2 because of polyglucosan body visceral myopathy and 1/2 to intestinal surgery). All patients had received antiemetics or prokinetics before (median of 5 drugs; 2-11). 1/7 (14%) received enteral supplements, 5/7 (72%) enteral nutrition through enteral tubes and 4/7 (57%) parenteral nutrition. 5/7 (72%) patients received 1mg of nabilone bd orally, 1/7 (14%) 2 mg bd through jejunostomy and 1/7 (14%) started nabilone at 2 mg bd orally, but had to be switched to 1 mg bd because of side-effects. The median treatment's duration was 9 days (7-35). Regarding the efficacy of nabilone, 3/7 (43%) had symptomatic improvement. In terms of side-effects 4/7 (57%) patients reported some incidence under the treatment such as headache, light-headedness, drowsiness, dizziness or hallucinations. Patients with refractory GID vomiting despite multiple anti-sickness are difficult to treat. Nabilone improved symptoms in almost half of the patients although adverse effects appeared in more than 50%. Doses higher than 1 mg bd po did not show benefit. Although our study has important limitations, nabilone might be a temporary measure in these patients. Side-effects should be taken into consideration

Investigating the cytotoxic effect of some medicinal plants from northern parts of Iran

Abstract Background and objectives: Iran owns a rich and prestigious heritage of medicinal herbs but the majority of these plants have not yet undergone chemical, pharmacological and toxicological studies. In the present study some species form northern parts of Iran were evaluated for cytotoxicity. Methods: Sixteen medicinal plants were extracted with methanol and screened for their cytotoxic activities. The inhibition of cell growth for these extracts was evaluated against MCF-7, WEHI-164, HepG-2 and MDBK cell lines. Their 50% inhibitions of growth (IC 50 ) were determined by MTT assay. Moreover, cytotoxic evaluation of different fractions of the most potent species was performed. Results: Among examined samples, the IC 50 values of methanol extract of Centaurea bruguierana (DC.) Hand.-Mzt. on mentioned cell lines were found 47.30-87.40 µg/mL. In addition, the chloroform fraction of the species was cytotoxic with IC 50 values 17.00-23.03 µg/mL. Conclusion: It was concluded that the chloroform fraction of C. bruguierana was the best candidate for identification and isolation of active principles with cytotoxic effects. These results recommend further studies about this species