Features of the level of matrix metalloproteinase-2, -3, -9 and tissue inhibitors of metalloproteinases-1, -2, -3, -4 in the aqueous humor of patients with primary open-angle glaucoma

Aim. To study the content of matrix metalloproteinase (MMP)-2, -3, -9 and tissue inhibitors of metalloproteinases (TIMPs) -1, -2, -3, -4 in the aqueous humor of patients with moderate primary open-angle glaucoma (POAG).Materials and methods. The experimental group included 47 patients with verified moderate primary open-angle glaucoma. The control group consisted of 26 patients with uncomplicated cataract. The levels of MMP-2, -3, -9 were determined with Luminex Performance Human MMP Magnetic Panel 3-plex kit (R&D Systems, USA), the concentration of TIMPs-1, -2, -3, - 4 was determined with the Human TIMP Magnetic Luminex Performance Assay 4-plex kit (R&D Systems, USA). The study was carried out using flow-through field fluorometry on a Bio-Plex 200 double-beam laser analyzer (Bio-Rad, USA).Results. The study showed a statistically significant increase in the levels of matrix metalloproteinase-2 and tissue inhibitors of matrix metalloproteinases-1, -2, -3, -4 in the aqueous humor of patients with moderate POAG compared with patients with uncomplicated cataract.Conclusion. The obtained data on high concentrations and imbalance in the levels of matrix metalloproteinases and their tissue inhibitors in the aqueous humor of patients with moderate POAG confirm the role of local inflammation, as well as impairments in the structure of the extracellular matrix and its remodeling in the mechanisms of development of this pathology.

UV Spectrophotometric Method for Quantification of Rivastigmine Tartrate in Simulated Nasal Fluid: Development and Validation

Background: Rivastigmine Tartrate belongs to the class of cholinesterase inhibitors in Anti-alzheimer’s disease with optimum therapeutic efficacy. Till now no validated method of its quantification has been reported in simulated nasal fluid. Objective: The current research investigation aims to develop a rapid, simple, and reliable UV spectrophotometric method for the quantitative determination of the pure form of Rivastigmine Tartrate in SNF. Method: A suitable method was developed by using double beam UV spectrophotometer and selection of a suitable solvent system for estimation of Rivastigmine Tartrate at absorbance maxima 263nm in SNF. The method was validated for various parameters like including accuracy, linearity and precision as per the International Conference on Harmonization guidelines. Results: The method developed by selecting simulated nasal fluid as the solvent system satisfied the optimum condition of the good quality peak at the selected wavelength. The results proposed the developed method for Rivastigmine Tartrate quantification in the simulated nasal fluid to be linear in the working concentration range of 5-60 µg/ml with a co-relation coefficient of 0.998. The % accuracy was found to be 99.8 -100.57. The % RSD values were < 2 while LOD & LOQ values were detected to be 0.316 and 1.053 respectively. Conclusion: The stated method was analyzed to be rapid, accurate, reliable, and precise. Further, it can be used in checking the quality control parameters of the Rivastigmine Tartrate in routine analysis.

Rotational nonlinear double-beam energy harvesting

This paper presents an investigation of the performance of a coupled rotational double-beam energy harvester (DBEH) with magnetic nonlinearity. Two spring-connected cantilever beams are fixed on a rotating disc. Repelling magnets are attached to the frame and to the lower beam tip, and an equal-mass block is attached to the tip of the upper beam. To describe the dynamic response, a theoretical model related to the rotational motion of the coupled cantilever beam is derived from the Lagrange equations. In addition, the harmonic balance method, together with the arc-length continuation method, is applied to obtain the frequency response functions (FRFs). Parametric studies are then conducted to analyze the effect of varying the parameters on the energy harvesting performance, and numerical analysis is performed to validate the analytical solutions. Finally, the theoretical model is verified by forward- and reverse-frequency-sweeping experiments. The DBEH in rotational motion can perform effective energy harvesting over a wide range of rotational frequencies (10 to 35 rad/s). The upper beam is found to exhibit better energy harvesting efficiency than the lower beam around the resonant frequency. This study effectively broadens the energy harvesting bandwidth and provides a theoretical model for the design of nonlinear magnet-coupled double-beam structure in rotational energy harvesting.

Investigating homeopathic preparations with light spectroscopy

Background Several series of experiments from our research group have shown ultraviolet (UV) light transmission of homeopathic preparations to slightly but significantly differ from controls. We now investigated whether visible and near infrared spectroscopy were also useful for exploring properties of homeopathic preparations. Materials and methods Homeopathic preparations of copper sulfate (CuSO4), hypericum and sulfur (S8) were produced in 30 sequential steps of 1:100 dilutions (c-preparations). As controls, succussed potentization medium was used. Transmission of the samples from 190-1100nm was measured 4 times on 5 days with a double beam Shimadzu UV PC 1601 spectrophotometer. To correct for the daily variations of the spectrophotometer, transmission of the samples at each nm was divided by the average transmission of the controls. Median transmissions of the samples were calculated for the ranges of 190-340nm (near and middle UV), 340-640nm (visible light without red), and 640-1100nm (red and near infrared). Differences in the median transmission between potency levels from 6c to 30c were determined using Kruskal-Wallis and Jonckheere-Terpstra tests. Results Differences in transmissions of the various potency levels were more pronounced in the UV range than in the visible or red/near infrared range. The Kruskal-Wallis test revealed significant differences for homeopathic preparations of CuSO4, hypericum and S8 in the UV range (p=0.032, 0.008, 0.009, respectively) and of S8 in the visible range (p=0.026). Jonckheere's test showed a tendency towards ascending medians with ascending potency levels for CuSO4 in the UV range (p=0.080). Significant trends were revealed for hypericum in the visible range (p=0.042, descending medians) and S8 in the UV range (p=0.015, ascending medians). Conclusion UV spectroscopy seemed to be more suitable for investigating homeopathic preparations than visible or near infrared spectroscopy, since differences in transmission were more pronounced in the UV range.

Degradation of Imidacloprid Residue on Red Tomatoes (Solanum lycopersicum) by Advanced Oxidation Processes and Analysis using Spectrophotometer and HPLC

The insecticide imidacloprid (C9H10ClN5O2) common used by farmers to control pests on red tomato plants, is a dangerous substance classified as a Class II toxic. The imidacloprid residue in red tomatoes enters the body, it will lead to health problems. The purpose of this study was to determine the percentage of imidacloprid residue that can be degraded using the Advanced Oxidation Processes (AOPs) method, which includes sonolysis, sonozolysis, ozonolysis, ozone water, and the effect of various parameters. Processing time, water volume, and red tomato mass were the test parameters studied. The change in imidacloprid residue concentration during the degradation process was measured using a UV/Vis spectrophotometer (double beam) with a wavelength of 200-400 nm and HPLC with mobile phase composition used was acetonitrile/water (65:35 v/v). With a processing time of 10 minutes, the imidacloprid residue in red tomatoes can be degraded 57.38% by sonozonolysis, 63.51 % by sonolysis, 85.17 % by ozonolysis, and 88.76 % by ozone water. The imidacloprid residue in 75 g of red tomatoes could be removed as much as 91.65% by treating with ozone water for 15 minutes. HPLC analysis showed that no intermediate compounds were detected in the imidacloprid residue degradation process in red tomatoes.

Total Harmonic Distortion of a Piezoelectric MEMS Loudspeaker in an IEC 60318-4 Coupler Estimation Using Static Measurements and a Nonlinear State Space Model

We propose a method to evaluate the Total Harmonic Distortion generated by a cantilever-based PZT loudspeaker inside an IEC 60318-4 coupler. The model is validated using experimental data of a commercial loudspeaker. Using the time domain equations of the equivalent electrical circuit of the loudspeaker inside the coupler and a state space formulation, the acoustic pressure response is calculated and compared to the measurement of the manufacturer. Next, the stiffness, transduction and capacitance nonlinear functions are evaluated with a Double-Beam Laser Interferometer (DBLI) and a nanoindenter on test devices and on the commercial loudspeaker. By introducing the nonlinear functions into the model as amplitude-dependent parameters, the THD generated by the loudspeaker is calculated and compared to the value provided by the manufacturer. The good agreement between the measurement and the simulation could allow for a rather quick simulation of the performance of similarly designed loudspeakers at the early stage of the design, by only estimating the static linearity of the main nonlinearity sources.

Bridge Damping Extraction Method from Vehicle–Bridge Interaction System Using Double-Beam Model

When vehicles interact with a bridge, a vehicle–bridge interaction (VBI) system is created. The frequency and modal shape of VBI systems have been widely studied, but the damping of VBI systems has not been adequately investigated. In recent years, several incidents of abnormal bridge vibration due to changes in bridge damping have occurred and aroused widespread concern in society. Damping is an important evaluation index of structural dynamic performance. Knowing the damping ratio of a VBI system is useful for analyzing the damping changes while a bridge is in service. This paper presents a method to extract bridge damping values from a VBI system, which can serve as a guide for bridge damping evaluation. First, a double-beam theoretical model was used to simplify the VBI system for cases involving uniform traffic flow. The damping ratio equation for the simplified VBI system was obtained using the extended dynamic stiffness method (EDSM). A double-beam finite element model and a VBI finite element model were established. The damping ratios of the two models were separately calculated and then compared with the simplified VBI model results. The results verified the accuracy of the simplified method. This paper then explains that bridge damping values can be extracted by estimating the equivalent traffic flow parameters and using the damping formula for the simplified VBI system. The bridge damping ratios extracted using this method in an engineering case ranged from 0.75% to 0.78%, which is smaller than the range that was directly identified using monitoring data (0.83–1.19%). The results show that the method can effectively extract bridge damping ratios and improve damping ratio identification.