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11.
Justyna Popi Agnieszka Gunia-Krzyak Karolina Soczyska Paulina Koczurkiewicz-Adamczyk Kamil Piska Katarzyna Wjcik-Pszczoa Dorota elaszczyk Anna Krupa Pawe mudzki Henryk Marona Elbieta Pkala 《International journal of molecular sciences》2021,22(1)
Excessive UV exposure contributes to several pathological conditions like skin burns, erythema, premature skin aging, photodermatoses, immunosuppression, and skin carcinogenesis. Effective protection from UV radiation may be achieved with the use of sunscreens containing UV filters. Currently used UV filters are characterized by some limitations including systemic absorption, endocrine disruption, skin allergy induction, and cytotoxicity. In the research centers all over the world new molecules are developed to improve the safety, photostability, solubility, and absorption profile of new derivatives. In our study, we designed and synthesized seventeen novel molecules by combining in the structures two chromophores: xanthone and (E)-cinnamoyl moiety. The ultraviolet spectroscopic properties of the tested compounds were confirmed in chloroform solutions. They acted as UVB or UVA/UVB absorbers. The most promising compound 9 (6-methoxy-9-oxo-9H-xanthen-2-yl)methyl (E)-3-(2,4-dimethoxyphenyl)acrylate) absorbed UV radiation in the range 290–369 nm. Its photoprotective activity and functional photostability were further evaluated after wet milling and incorporation in the cream base. This tested formulation with compound 9 possessed very beneficial UV protection parameters (SPFin vitro of 19.69 ± 0.46 and UVA PF of 12.64 ± 0.32) which were similar as broad-spectrum UV filter tris-biphenyl triazine. Additionally, compound 9 was characterized by high values of critical wavelength (381 nm) and UVA/UVB ratio (0.830) thus it was a good candidate for broad-spectrum UV filter and it might protect skin against UVA-induced photoaging. Compound 9 were also shown to be photostable, non-cytotoxic at concentrations up to 50 µM when tested on five cell lines, and non-mutagenic in Ames test. It also possessed no estrogenic activity, according to the results of MCF-7 breast cancer model. Additionally, its favorable lipophilicity (miLogP = 5.62) does not predispose it to penetrate across the skin after topical application. 相似文献
12.
This paper proposes a new multi-objective framework for optimal placement and sizing of the active power filters (APFs) with satisfactory and acceptable standard levels. total harmonic distortion (THD) of voltage, harmonic transmission line loss (HTLL), motor load loss function (MLLF), and total APFs currents are the four objectives considered in the optimization, while harmonic distortions within standard level, and maximum allowable APF size, are modeled as constraints. The proposed model is one of non-convex optimization problem having a non-linear, mixed-integer nature. Since, a new modified harmony search algorithm (MHSA) is used and followed by a min–max technique in order to obtain the final optimal solution. The harmony search algorithm is a recently developed optimization algorithm, which imitates the music improvisation process. In this process, the Harmonists improvise their instrument pitches searching for the perfect state of harmony. The newly developed method has been applied on the IEEE 18-bus test system and IEEE 30-bus test system by different scenarios and cases to demonstrate the feasibility and effectiveness of the proposed method. The detailed results of the case studies are presented and thoroughly analyzed. The obtained results illustrate the sufficiency and profitableness of the newly developed method in the placement and sizing of the multiple active power filters, when compared with other methods. 相似文献
13.
Estimation of film accumulation is necessary for the successful operational management of percolating filters. Prevention of ponding and loss of performance due to excessive film accumulation, and the optimization of the recirculation and alternating double filtration processes can only be achieved by regular monitoring of film growth. Five methods of determining film accumulation are compared; total film weight, total dry solids, volatile solids, percentage settlement of solids and the neutron scattering technique. The methods were used to monitor the film growth in pilot filters containing a mineral and a random plastics medium, over two twelve-month loading periods at 1.68 m3 m−3 day−1 (0.28 kg BOD m−3 day−1) and 3.37 m3 m−3 day−1 (0.63 kg BOD m−3 day−1).
Good correlations (P < 0.001) are found between all methods at the lower loading although the neutron scattering results are not significantly correlated (P > 0.10) with any of the gravimetric methods at the higher loading. Although the neutron scattering technique does provide a rapid and sensitive measure of hydrogen atoms in the filter, the results, expressed as percentage saturation of the voids, are not directly transferable to film weights and should be treated separately and not as a true measure of film accumulation. 相似文献
14.
Davyhulme sewage-treatment works, which serves the Manchester drainage area, is one of the lagest in the UK. The dry-weather flow is 300 000 m3 /d, and the plant receives a wide range of industrial effluents. The works has been identified as a major source of pollution in the Mersey estuary, with an average discharge of 6500 kg ammonia/day. As part of its initiative to improve the Mersey estuary, North West Water intends to reduce the daily ammonia load from Davyhulme to about 1000 kg/d by 1995. In order to assess the capabilities of both conventional and novel processes to achieve this degree of ammonia removal, a number of on-site pilot plants were established. This paper reports on the pilot-plant studies and the selection of process options. Recommendations with regard to design parameters and final process selection are given. 相似文献
15.
《International Journal of Circuit Theory and Applications》2017,45(5):595-612
Novel topologies of fractional‐order generalized filters are introduced in this paper. These offer the following benefits: (1) realization of lowpass, highpass, bandpass, allpass, or bandstop filter functions by the same topology; (2) resistorless realizations; (3) electronic adjustment of their frequency characteristics as well as their order; and (4) employment of only grounded capacitors. All the above have been achieved using Operational Transconductance Amplifiers as active elements and appropriate multi‐feedback topologies. The behavior of the proposed designs is verified through simulation results using the Cadence IC design suite and the Design Kit provided by the Austrian Micro Systems 0.35‐µm complementary metal–oxide–semiconductor process. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Analytical synthesis of voltage‐mode even/odd‐nth‐order differential difference current conveyor and fully differential current conveyor II‐grounded resistor and capacitor universal filter structures 下载免费PDF全文
Chun‐Ming Chang M. N. S. Swamy Ahmed M. Soliman 《International Journal of Circuit Theory and Applications》2015,43(10):1263-1310
A complete definition of an odd/even‐nth‐order notch or band‐reject filter transfer function is presented. Based on the differences between the input voltage and (i) an nth‐order high‐pass; (ii) a traditional nth‐order notch; and (iii) an nth‐order all‐pass filtering transfer function, a systematic method has been proposed to derive a universal filter structure that can realize voltage‐mode odd/even‐nth‐order low‐pass, band‐pass, high‐pass, all‐pass and traditional notch filters. The intrinsic capability of voltage‐mode addition and subtraction of the two active elements, differential difference current conveyors and fully differential current conveyors, is used to advantage in the aforementioned synthesis procedure. Based upon the definition of an nth‐order notch or band‐reject filter transfer function proposed in this paper, the aforementioned universal one has been further extended to the newly defined nth‐order band rejection filter. The voltage and current tracking errors of the two active elements are compensated by varying the resistances of the proposed filter. Filtering feasibility, stability, component sensitivities, linear and dynamic ranges, power consumption, and noise are simulated using H‐Spice with 0.35 µm process. Compared to some of the recently reported universal biquads, the new one is shown to enjoy the lowest component sensitivities and the best output accuracy for all‐pass signals. Moreover, Monte Carlo and two‐tone tests for intermodulation linearity simulations are also investigated. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
19.
Georgia Tsirimokou Costas Laoudias Costas Psychalinos 《International Journal of Circuit Theory and Applications》2015,43(9):1105-1126
Novel configurations of fractional‐order filter topologies, realized through the employment of the concept of companding filtering, are introduced in this paper. As a first step, the design procedure is presented in a systematic algorithmic way, while in the next step, the basic building blocks of sinh‐domain and log‐domain integrators are presented. Because of the employment of metal–oxide–semiconductor (MOS) transistors operated in the subthreshold region, the derived filter structures offer the capability for operation in an ultra‐low‐voltage environment. In addition, because of the offered resistorless realizations, the proposed topologies are reconfigurable, in the sense that the order of the filter could be chosen through appropriate bias current sources. The performance of the derived fractional‐order filters has been evaluated through simulation and comparison results using the Analog Design Environment of the Cadence software and MOS transistor parameters provided by the Taiwan Semiconductor Manufacturing Company (TSMC) 180‐nm complementary MOS (CMOS) process. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
20.
High‐tuning‐range CMOS band‐pass IF filter based on a low‐Q cascaded biquad optimization technique 下载免费PDF全文
Pietro Monsurrò Salvatore Pennisi Giuseppe Scotti Alessandro Trifiletti 《International Journal of Circuit Theory and Applications》2015,43(11):1615-1636
A design procedure for high‐order continuous‐time intermediate‐frequency band‐pass filters based on the cascade of low‐Q biquadratic cells is presented. The approach is well suited for integrated‐circuit fabrication, as it takes into account the maximum capacitance spread dictated by the available technology and maximum acceptable sensitivity to component variations. A trade‐off between noise and maximum linear range is also met. A novel, wide‐tuning‐range transconductor topology is also described. Based on these results, a 10‐pole band‐pass filter for a code division multiple‐access satellite receiver has been designed and tested. The filter provides tunable center frequency (f0) from 10 to 70 MHz and exhibits a 28‐MHz bandwidth around f0 = 70 MHz with more than 39‐dB attenuation at f0/2 and 2f0. Third‐order harmonic rejection is higher than 60 dB for a 1‐Vpp 70‐MHz input, and equivalent output noise is lower than 1 mVrms. The circuit is fabricated in a 0.25‐µm complementary metal oxide semiconductor process, and the core consumes 12 mA from a 2.5‐V supply, offering the best current/pole ratio figure. The die area resulted to be 0.9 × 1.1 mm2. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献