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Artigos de revistas sobre o tema "QCM"

Autor: Grafiati

Publicado: 4 de junho de 2021

Última modificação: 7 de setembro de 2023

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1

Tahir, Iqmal, Mudasir Mudasir, Irza Yulistia e Mustofa Mustofa. "QUANTITATIVE STRUCTURE-ACTIVITY RELATIONSHIP ANALYSIS (QSAR) OF VINCADIFFORMINE ANALOGUES AS THE ANTIPLASMODIAL COMPOUNDS OF THE CHLOROQUINOSENSIBLE STRAIN". Indonesian Journal of Chemistry 5, n.º 3 (15 de junho de 2010): 255–60. http://dx.doi.org/10.22146/ijc.21800.

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Quantitative Structure-Activity Relationship (QSAR) analysis of vincadifformine analogs as an antimalarial drug has been conducted using atomic net charges (q), moment dipole (), LUMO (Lowest Unoccupied Molecular Orbital) and HOMO (Highest Occupied Molecular Orbital) energies, molecular mass (m) as well as surface area (A) as the predictors to their activity. Data of predictors are obtained from computational chemistry method using semi-empirical molecular orbital AM1 calculation. Antimalarial activities were taken as the activity of the drugs against chloroquine-sensitive Plasmodium falciparum (Nigerian Cell) strain and were presented as the value of ln(1/IC50) where IC50 is an effective concentration inhibiting 50% of the parasite growth. The best QSAR model has been determined by multiple linier regression analysis giving QSAR equation: Log (1/IC50) = 9.602.qC1 -17.012.qC2 +6.084.qC3 -19.758.qC5 -6.517.qC6 +2.746.qC7 -6.795.qN +6.59.qC8 -0.190. -0.974.ELUMO +0.515.EHOMO -0.274. +0.029.A -1.673 (n = 16; r = 0.995; SD = 0.099; F = 2.682) Keywords: QSAR analysis, antimalaria, vincadifformine.

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2

Chen, Qiao, Xianhe Huang, Yao Yao e Kunlei Mao. "Analysis of the Effect of Electrode Materials on the Sensitivity of Quartz Crystal Microbalance". Nanomaterials 12, n.º 6 (16 de março de 2022): 975. http://dx.doi.org/10.3390/nano12060975.

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This paper investigated the effect of electrode materials on the performance of quartz crystal microbalance (QCM) sensors by means of theoretical calculation, experiment, and finite element analysis methods. First, we calculated the particle displacement amplitude and thus obtained the mass sensitivity function distribution of QCMs with gold, silver and aluminum electrodes, and found that the QCM with the gold electrode has the highest mass sensitivity at the center of the electrode. Then, we tested the humidity-sensing performance of QCMs with gold, silver, and aluminum electrodes using graphene oxide (GO) as the sensitive material, and found that the QCM with the gold electrode has higher humidity sensitivity. Finally, we used the finite element analysis software COMSOL Multiphysics to simulate the specific electrode material parameters that affect the sensitivity of the QCMs. The simulation results show that the density and Young’s modulus of the electrode material parameters mainly affect the sensitivity. The results of this paper are instructive for optimizing QCM sensor performance and improving the capability of QCM quantitative analysis.

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3

Huang, Xianhe, Qiao Chen, Wei Pan, Jianguo Hu e Yao Yao. "Assessing the Mass Sensitivity for Different Electrode Materials Commonly Used in Quartz Crystal Microbalances (QCMs)". Sensors 19, n.º 18 (14 de setembro de 2019): 3968. http://dx.doi.org/10.3390/s19183968.

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Mass sensitivity is vital for quartz crystal microbalance (QCM)-based data analysis. The mass sensitivity distribution of QCMs may differ greatly depending on the shapes, thicknesses, sizes, and materials of the metal electrodes. This is not considered by the Sauerbrey equation, and has a large potential to cause errors in QCM-based data analysis. Many previous works have studied the effects of shape, thickness, and size of metal electrodes on mass sensitivity. However, it is necessary to continue to clarify the relationship between the mass sensitivity and the electrode material of the QCM. In this paper, the results of both theoretical calculation and experimental analysis showed that the mass sensitivity of QCMs with gold electrodes is higher than that of the QCMs with silver electrodes, which in turn indicated that the mass sensitivity of QCMs varies with the electrode material. Meanwhile, the results of this study showed that the mass sensitivity of QCMs with different electrode materials is not proportional to the density of the electrode materials. This result suggests that, in order to obtain more accurate results in the practical applications of QCMs, the influence of electrode material on the mass sensitivity of the QCMs must be considered.

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4

Nowocień, Sylwester, Radosław Sławomir Wielgus e Janusz Mroczka. "Precision Temperature Control System with Low EMI for Applications in Analyzing Thermal Properties of Highly Sensitive Piezoelectric Sensors". Sensors 22, n.º 21 (5 de novembro de 2022): 8525. http://dx.doi.org/10.3390/s22218525.

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A low electromagnetic interference (EMI), precision temperature control system for sensitive piezoelectric sensors stabilization and their thermal characteristics research was proposed. Quartz crystal microbalance (QCM) was chosen as the device to be tested. Recently, QCMs found use in many fields of study such as biology, chemistry, and aerospace. They often operate in harsh environments and are exposed to many external factors including temperature fluctuations, to which QCMs are highly susceptible. Such disturbances can cause undesirable resonant frequency shifts resulting in measurement errors that are difficult to eliminate. The proposed solution enables measurements of QCMs thermal characteristics, effectiveness evaluation of temperature compensation methods, and testing of the frequency stability. As a part of the developed solution, two independent temperature regulators were used: first to maintain the QCM crystal at desired temperature, and second to keep the QCM oscillator circuit at fixed temperature. The single regulator consists of a thermoelectric module (TEC) used for both heating and cooling. Two considered TEC driving methods were compared in terms of EMI and their impact on the QCM signal quality. The proposed system was examined for its temperature stabilization capability showing high stability of 11 mKp-p for one hour and the setpoint accuracy of ±15 mK in the full temperature range.

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Na Songkhla, Sawit, e Takamichi Nakamoto. "Interpretation of Quartz Crystal Microbalance Behavior with Viscous Film Using a Mason Equivalent Circuit". Chemosensors 9, n.º 1 (2 de janeiro de 2021): 9. http://dx.doi.org/10.3390/chemosensors9010009.

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In odor sensing based on Quartz Crystal Microbalances (QCMs), the sensing film is crucial for both sensor sensitivity and selectivity. The typical response of the QCM due to sorption is a negative frequency shift. However, in some cases, the sorption causes a positive frequency shift, and then, Sauerbrey’s equation and Kanazawa’s equation cannot be applied to this situation. We model the QCM response with a Mason equivalent circuit. The model approximates a single layer of a uniform viscous coating on the QCM. The simulation of the equation circuit shows the possibility of the positive frequency change when the sorption occurs, which is the situation we find in some of the odor sensing applications. We measured the QCM frequency and resistance using the Vector Network Analyzer (VNWA). The QCMs were coated with glycerol, PEG2000, and PEG20M. To simulate odor exposure, a microdispenser was used to deposit the water. A positive frequency shift was observed in the case of PEG2000, and a negative frequency change was obtained for PEG20M. These results can be explained by the Mason equivalent circuit, with the assumption that when the film is exposed to water, its thickness increases and its viscosity decreases.

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Ortiz Monsalve, Camilo, Jorge Mario Guerra González e Marisol Jaramillo Grajales. "Immobilization of DNA probes on a high frequency piezoelectric biosensor". DYNA 87, n.º 212 (1 de janeiro de 2020): 163–68. http://dx.doi.org/10.15446/dyna.v87n212.82309.

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In recent years, researchers have taken to biosensors as effective tools for detection due to their portability, low-cost, fast response, and practicality. Piezoelectricity gave way to quartz crystal microbalances (QCM), of which high-frequency QCMs (HFF-QCM 100MHz) are still being researched. In this paper, we use DNA immobilization on a HFF-QCM via self-assembled monolayers (SAM) technique. Immobilization was initially verified with ATR-FTIR. Then, DNA was immobilized in real time on the HFF-QCM crystals. A variation in the phase of the signal suggests fixation of DNA to the surface, in accordance with ATR-FTIR results. A density of 629 ng/cm2 was computed. Also, a positive correlation between immobilized DNA and DNA concentration, and the appearance of a saturation point between 1 and 5 μM were shown after analysis of different DNA concentrations.

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7

Burda, Ioan. "Quartz Crystal Microbalance with Impedance Analysis Based on Virtual Instruments: Experimental Study". Sensors 22, n.º 4 (15 de fevereiro de 2022): 1506. http://dx.doi.org/10.3390/s22041506.

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The impedance quartz crystal microbalance (QCMI) is a versatile and simple method for making accurate measurements of the QCM sensor electrical parameters. The QCM sensor provides access to the physical parameters of the sample beyond the mass per unit area by measuring the dissipation factor, or another equivalent, ensuring a detailed analysis of the surface. By establishing a cooperative relationship between custom software and modular configurable hardware we obtain a user-defined measurement system that is called a virtual instrument. This paper aims primarily to improve and adapt existing concepts to new electronics technologies to obtain a fast and accurate virtual impedance analyzer (VIA). The second is the implementation of a VIA by software to cover a wide range of measurements for the impedance of the QCM sensor, followed by the calculation of the value of lumped electrical elements in real time. A method for software compensation of the parallel and stray capacitance is also described. The development of a compact VIA with a decent measurement rate (192 frequency points per second) aims, in the next development steps, to create an accurate impedance analyzer for QCM sensors. The experimental results show the good working capacity of QCMI based on VIA.

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Tamaki, Ichiro, e Yae Yamada. "Environmental pressure rather than ongoing hybridization is responsible for an altitudinal cline in the morphologies of two oaks". Journal of Plant Ecology 13, n.º 4 (26 de maio de 2020): 413–22. http://dx.doi.org/10.1093/jpe/rtaa028.

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Abstract Aims In a contact zone between related taxa, phenotypic variation can result from genetic and/or environmental gradients. This study aimed to clarify the cause of phenotypic variation in leaf morphology of two Quercus crispula varieties—crispula (QCC) and mongolicoides (QCM)—in their contact zone along an altitudinal gradient. Methods We measured 6 morphological traits of leaves and recorded genotypes of 13 nuclear microsatellite loci for 48 individuals in the contact zone and 24 individuals in each of the reference populations of QCC and QCM. We constructed a model explaining the phenotypic variation (leaf morphology) in relation to environmental (altitude) and genetic (ancestry from the reference population) gradients. Important Findings Both morphological and genetic markers distinguished the two varieties in the reference populations well. We were able to confirm the power of both morphological and genetic markers. Individuals within the contact zone population had intermediate ancestry that was slightly biased to QCM ancestry, and the distribution of their morphologies overlapped with those of the two varieties in the reference populations. The effect of altitude on leaf morphological traits was significant, while that of ancestry was not. Distributions of ancestry and interclass heterozygosity in the contact zone population resembled those in F2 or later generation hybrids. These results indicate that in the contact zone between QCC and QCM, there is no ongoing hybridization, but environmental pressure has created an altitudinal gradient in morphological traits through phenotypic plasticity and/or variation in functional genes.

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9

Cho, Hyokjin, Guee-Won Moon, Hee-Jun Seo, Sang-Hoon Lee e Seok-Weon Choi. "Measurement of Molecular Contamination for Satellites Using a Quartz Crystal Microbalance (QCM)". Journal of the IEST 47, n.º 1 (14 de setembro de 2004): 107–10. http://dx.doi.org/10.17764/jiet.47.1.pr658527u268l7q1.

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Quartz Crystal Microbalances (QCMs) have been used to measure the molecular contamination for satellites in vacuum bake-out tests at the Korea Aerospace Research Institute (KARI). Through measurement using QCMs, the mass and the mass deposition rate of molecular contamination could be traced in real-time. Vacuum bake-out tests were performed for the satellite KAISTAT-4 Flight Model and its components under various temperature conditions. During these tests, QCM measurement data was obtained and materials from the cold plate were analyzed using a Gas Chromatograph-Mass Spectrometer (GC-MS). The characteristics of the QCM sensor were also observed.

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10

Addabbo, Tommaso, Ada Fort, Elia Landi, Riccardo Moretti, Marco Mugnaini e Valerio Vignoli. "Strategies for the Accurate Measurement of the Resonance Frequency in QCM-D Systems via Low-Cost Digital Techniques". Sensors 22, n.º 15 (31 de julho de 2022): 5728. http://dx.doi.org/10.3390/s22155728.

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In this paper, an FPGA (Field Programmable Gate Array)-based digital architecture for the measurement of quartz crystal microbalance (QCM) oscillating frequency of transient responses, i.e., in QCM-D (QCM and Dissipation) applications, is presented. The measurement system is conceived for operations in liquid, with short QCM transient responses due to the large mechanical load. The proposed solution allows for avoiding the complex processing systems typically required by the QCM-D techniques and grants frequency resolutions better than 1 ppm. The core of the architecture is a reciprocal digital frequency meter, combined with the preprocessing of the QCM signal through mixing operations, such as a step-down of the input frequency and reducing the measurement error. The measurement error is further reduced through averaging. Different strategies are proposed to implement the proposed measurement solution, comprising an all-digital circuit and mixed analog/digital ones. The performance of the proposed architectures is theoretically derived, compared, and analyzed by means of experimental data obtained considering 10 MHz QCMs and 200 μs long transient responses. A frequency resolution of about 240 ppb, which corresponds to a Sauerbrey mass resolution of 8 ng/cm2, is obtained for the all-digital solution, whereas for the mixed solution the resolution halves to 120 ppb, with a measurement time of about one second over 100 repetitions.

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11

Williams, P. Mickey, Thomas Forbes, Steven P. Lund, Kenneth D. Cole, Hua-Jun He, Chris Karlovich, Cloud P. Paweletz et al. "Validation of ctDNA Quality Control Materials Through a Precompetitive Collaboration of the Foundation for the National Institutes of Health". JCO Precision Oncology, n.º 5 (maio de 2021): 910–20. http://dx.doi.org/10.1200/po.20.00528.

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PURPOSE We report the results from a Foundation for the National Institutes of Health Biomarkers Consortium project to address the absence of well-validated quality control materials (QCMs) for circulating tumor DNA (ctDNA) testing. This absence is considered a cause of variance and inconsistencies in translating ctDNA results into clinical actions. METHODS In this phase I study, QCMs with 14 clinically relevant mutations representing single nucleotide variants, insertions or deletions (indels), translocations, and copy number variants were sourced from three commercial manufacturers with variant allele frequencies (VAFs) of 5%, 2.5%, 1%, 0.1%, and 0%. Four laboratories tested samples in quadruplicate using two allele-specific droplet digital polymerase chain reaction and three (amplicon and hybrid capture) next-generation sequencing (NGS) panels. RESULTS The two droplet digital polymerase chain reaction assays reported VAF values very close to the manufacturers’ claimed concentrations for all QCMs. NGS assays reported most single nucleotide variants and indels, but not translocations, close to the expected VAF values. Notably, two NGS assays reported lower VAF than expected for all translocations in all QCM mixtures, possibly related to technical challenges detecting these variants. The ability to call ERBB2 copy number amplifications varied across assays. All three QCMs provided valuable insight into assay precision. Each assay across all variant types demonstrated dropouts at 0.1%, suggesting that the QCM can serve for testing of an assay’s limit of detection with confidence claims for specific variants. CONCLUSION These results support the utility of the QCM in testing ctDNA assay analytical performance. However, unique designs and manufacturing methods for the QCM, and variations in a laboratory’s testing configuration, may require testing of multiple QCMs to find the best reagents for accurate result interpretation.

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12

Hagege, A. "QCM". Archives des Maladies du Coeur et des Vaisseaux - Pratique 2022, n.º 305 (fevereiro de 2022): 31–32. http://dx.doi.org/10.1016/j.amcp.2021.11.019.

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Clenet, Marie-France. "QCM". Revue Francophone d'Orthoptie 5, n.º 4 (outubro de 2012): 175. http://dx.doi.org/10.1016/j.rfo.2013.01.012.

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Amortila, Muriel. "QCM". Revue Francophone d'Orthoptie 6, n.º 1 (janeiro de 2013): 40. http://dx.doi.org/10.1016/j.rfo.2013.02.021.

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Berger-Martinet, Alexandra, e Muriel Amortila. "QCM". Revue Francophone d'Orthoptie 6, n.º 2 (abril de 2013): 84. http://dx.doi.org/10.1016/j.rfo.2013.05.006.

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Amortila, Muriel, e Annick Bouly de Lesdain. "QCM". Revue Francophone d'Orthoptie 6, n.º 4 (outubro de 2013): 201. http://dx.doi.org/10.1016/j.rfo.2013.10.010.

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Amortila, Muriel. "QCM". Revue Francophone d'Orthoptie 7, n.º 3 (julho de 2014): 254. http://dx.doi.org/10.1016/j.rfo.2014.09.015.

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Amortila, Muriel. "QCM". Revue Francophone d'Orthoptie 7, n.º 4 (outubro de 2014): 305. http://dx.doi.org/10.1016/j.rfo.2014.10.011.

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Amortila, Muriel. "QCM". Revue Francophone d'Orthoptie 8, n.º 1 (janeiro de 2015): 81. http://dx.doi.org/10.1016/j.rfo.2015.02.002.

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Amortila, Muriel. "QCM". Revue Francophone d'Orthoptie 8, n.º 2 (junho de 2015): 189–90. http://dx.doi.org/10.1016/j.rfo.2015.04.013.

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Amortila, Muriel. "QCM". Revue Francophone d'Orthoptie 8, n.º 3 (julho de 2015): 244. http://dx.doi.org/10.1016/j.rfo.2015.09.004.

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Amortila, Muriel. "QCM". Revue Francophone d'Orthoptie 9, n.º 1 (janeiro de 2016): 46. http://dx.doi.org/10.1016/j.rfo.2016.02.008.

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Amortila, Muriel. "QCM". Revue Francophone d'Orthoptie 9, n.º 2 (abril de 2016): 112. http://dx.doi.org/10.1016/j.rfo.2016.05.005.

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Derbré, Séverine. "QCM". Actualités Pharmaceutiques 53, n.º 534 (março de 2014): 21–24. http://dx.doi.org/10.1016/j.actpha.2013.12.024.

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Herpin, D. "QCM". Archives des Maladies du Coeur et des Vaisseaux - Pratique 2016, n.º 252 (novembro de 2016): 14. http://dx.doi.org/10.1016/j.amcp.2016.09.006.

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Roudaut, R. "QCM". Archives des Maladies du Coeur et des Vaisseaux - Pratique 2018, n.º 264 (janeiro de 2018): 32. http://dx.doi.org/10.1016/j.amcp.2017.10.016.

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Thambo, J. B. "QCM". Archives des Maladies du Coeur et des Vaisseaux - Pratique 2018, n.º 271 (outubro de 2018): 32–33. http://dx.doi.org/10.1016/j.amcp.2018.09.006.

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Artigou, J. Y. "QCM". Archives des Maladies du Coeur et des Vaisseaux - Pratique 2019, n.º 278 (maio de 2019): 19. http://dx.doi.org/10.1016/j.amcp.2019.03.012.

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Maupain, C., C. Bordet e E. Gandjbakhch. "QCM". Archives des Maladies du Coeur et des Vaisseaux - Pratique 2020, n.º 285 (fevereiro de 2020): 29. http://dx.doi.org/10.1016/j.amcp.2019.12.014.

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Messas, E. "QCM". Archives des Maladies du Coeur et des Vaisseaux - Pratique 2020, n.º 288 (maio de 2020): 19–20. http://dx.doi.org/10.1016/j.amcp.2020.03.009.

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Johannsmann, Diethelm, Arne Langhoff e Christian Leppin. "Studying Soft Interfaces with Shear Waves: Principles and Applications of the Quartz Crystal Microbalance (QCM)". Sensors 21, n.º 10 (17 de maio de 2021): 3490. http://dx.doi.org/10.3390/s21103490.

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The response of the quartz crystal microbalance (QCM, also: QCM-D for “QCM with Dissipation monitoring”) to loading with a diverse set of samples is reviewed in a consistent frame. After a brief introduction to the advanced QCMs, the governing equation (the small-load approximation) is derived. Planar films and adsorbates are modeled based on the acoustic multilayer formalism. In liquid environments, viscoelastic spectroscopy and high-frequency rheology are possible, even on layers with a thickness in the monolayer range. For particulate samples, the contact stiffness can be derived. Because the stress at the contact is large, the force is not always proportional to the displacement. Nonlinear effects are observed, leading to a dependence of the resonance frequency and the resonance bandwidth on the amplitude of oscillation. Partial slip, in particular, can be studied in detail. Advanced topics include structured samples and the extension of the small-load approximation to its tensorial version.

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Na Songkhla, Sawit, e Takamichi Nakamoto. "Overview of Quartz Crystal Microbalance Behavior Analysis and Measurement". Chemosensors 9, n.º 12 (10 de dezembro de 2021): 350. http://dx.doi.org/10.3390/chemosensors9120350.

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Quartz Crystal Microbalance (QCM) is one of the many acoustic transducers. It is the most popular and widely used acoustic transducer for sensor applications. It has found wide applications in chemical and biosensing fields owing to its high sensitivity, robustness, small sized-design, and ease of integration with electronic measurement systems. However, it is necessary to coat QCM with a sensing film. Without coating materials, its selectivity and sensitivity are not obtained. At present, this is not an issue, mainly due to the advancement of oscillator circuits and dedicated measurement circuits. Since a new researcher may seek to understand QCM sensors, we provide an overview of QCM from its fundamental knowledge. Then, we explain some of the recent QCM applications both in gas-phase and liquid-phase. Next, the theory of QCM is introduced by using piezoelectric stress equations and the Mason equivalent circuit, which explains how the QCM behavior is obtained. Then, the conventional equations that govern QCM behaviors in terms of resonant frequency and resistance are described. We show the behavior of QCM with a viscous film based on the acoustic wave equation and Mason equivalent circuit. Then, we present various existing QCM electronic measurement methods. Furthermore, we describe the experiment on QCM with viscous loading and its interpretation based on the Mason equivalent circuit. Lastly, we review some theoretical models to describe QCM behavior with various models.

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Wei, Zhenfang, Jianguo Hu, Yuanyuan Li e Jing Chen. "Effect of Electrode Thickness on Quality Factor of Ring Electrode QCM Sensor". Sensors 22, n.º 14 (9 de julho de 2022): 5159. http://dx.doi.org/10.3390/s22145159.

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As a key type of sensor, the quartz crystal microbalance (QCM) has been widely used in many research areas. Recently, the ring electrode QCM sensor (R-QCM) with more uniform mass sensitivity has been reported. However, the quality factor (Q-factor) of the R-QCM has still not been studied, especially regarding the effect of electrode thickness on the Q-factor. Considering that the Q-factor is one of crucial parameter to the QCM and it is closely related to the output frequency stability of the QCM, we study the effect of different electrode thicknesses on the Q-factor of the R-QCM in this paper. On the other hand, we clarify the relationship between the electrode thickness and the Q-factor of the R-QCM. The measurement results show that the average Q-factor increases with increases in the thickness of ring electrodes generally; however, the resonance frequency of the QCM resonator decreases with increases in the thickness. The low half-bandwidth (2Γ < 1630 Hz) of the R-QCM shows that the frequency performance is good. Additionally, the R-QCM has a higher Q-factor (Q > 6000), which indicates that it has a higher frequency stability and can be applied in many research areas.

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Yoshimine, Hiroshi, Kai Sasaki e Hiroyuki Furusawa. "Pocketable Biosensor Based on Quartz-Crystal Microbalance and Its Application to DNA Detection". Sensors 23, n.º 1 (27 de dezembro de 2022): 281. http://dx.doi.org/10.3390/s23010281.

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Quartz-crystal microbalance (QCM) is a technique that can measure nanogram-order masses. When a receptor is immobilized on the sensor surface of a QCM device, the device can detect chemical molecules captured by the mass change. Although QCM devices have been applied to biosensors that detect biomolecules without labels for biomolecular interaction analysis, most highly sensitive QCM devices are benchtop devices. We considered the fabrication of an IC card-sized QCM device that is both portable and battery-powered. Its miniaturization was achieved by repurposing electronic components and film batteries from smartphones and wearable devices. To demonstrate the applicability of the card-sized QCM device as a biosensor, DNA-detection experiments were performed. The card-sized QCM device could detect specific 10-mer DNA chains while discerning single-base differences with a sensitivity similar to that of a conventional benchtop device. The card-sized QCM device can be used in laboratories and in various other fields as a mass sensor.

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Kim, Min-Hee, In-Keun Yu e Seong-Ho Choi. "Development of an Ionic Quartz Crystal Microbalance (QCM) Sensors for the Detection of Na+ and K+ in Human Urine". Sensor Letters 17, n.º 9 (1 de setembro de 2019): 671–79. http://dx.doi.org/10.1166/sl.2019.4125.

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In this study, we developed a quartz crystal microbalance (QCM) ionic sensor that can determine Na+ and K+ in human urine by the immobilization of crown ether as an ionic selector on a QCM electrode. In detail, –COOH was first introduced onto the QCM electrode surface by electrochemical copolymerization of thiophene and 3-thiopheneacetic acid, and then crown ether was introduced as an ionic selector onto the –COOH-modified QCM electrode by amide bond reaction. The prepared QCM ionic sensor was evaluated by FT-IR spectroscopy, SEM, contact angle, and cyclic voltammetry to confirm its successful fabrication. A prepared QCM ionic sensor with 4′-aminobenzo18-crown-6 adsorbed at 0.344 μg to K+ cation in this experiment. The Na+ cation was 0.360 mg in a human urine sample with a prepared QCM ionic sensor with 4′-aminobenzo-15-crown-5 and the K+ cation in a real human urine sample was 0.280 mg with a QCM ionic sensor with 4-aminobenzo18-crown-6, respectively. According to these results, the prepared QCM ionic sensor could be used to detection of sodium and potassium concentrations in human urine samples.

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Miyake, Akiko, Satoshi Komasa, Yoshiya Hashimoto, Yutaka Komasa e Joji Okazaki. "Adsorption of Saliva Related Protein on Denture Materials: An X-Ray Photoelectron Spectroscopy and Quartz Crystal Microbalance Study". Advances in Materials Science and Engineering 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/5478326.

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The aim of this study was to evaluate the difference in the adsorption behavior of different types of bovine salivary proteins on the PMMA and Ti QCM sensors are fabricated by spin-coating and sputtering onto bare QCM sensors by using QCM and X-ray photoelectron spectroscopy (XPS). SPM, XPS, and contact angle investigations were carried out to determine the chemical composition and surface wettability of the QCM surface. We discuss the quality of each sensor and evaluate the potential of the high-frequency QCM sensors by investigating the binding between the QCM sensor and the proteins albumin and mucin (a salivary-related protein). The SPM image showed a relatively homogeneous surface with nano-order roughness. The XPS survey spectra of the thin films coated on the sensors were similar to the binding energy of the characteristic spectra of PMMA and Ti. Additionally, the amount of salivary-related protein on the PMMA QCM sensor was higher than those on the Ti and Au QCM sensors. The difference of protein adsorption is proposed to be related to the wettability of each material. The PMMA and Ti QCM sensors are useful tools to study the adsorption and desorption of albumin and mucin on denture surfaces.

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Wang, Zhenqiang, Mingqing Yang e Junhui He. "Sensing Properties of GO and Amine-Silica Nanoparticles Functionalized QCM Sensors for Detection of Formaldehyde". International Journal of Nanoscience 13, n.º 05n06 (outubro de 2014): 1460011. http://dx.doi.org/10.1142/s0219581x14600114.

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In the current work, graphene oxides (GO) and Amine-Functionalized Silica Nanoparticles ( NH 2-SNs) were used as sensing layer on quart crystal microbalance (QCM) for detection of HCHO gas. The GO and NH 2-SNs functionalized QCM resonators all had a significant response to HCHO gas. The sensitivity of GO functionalized QCM resonator is 0.04 Hz/(μg⋅ppm), which is four times as high as that of NH 2-SNs functionalized QCM resonator (0.01 Hz/(μg⋅ppm)). The GO functionalized QCM resonators would be of benefit in area of environmental applications.

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Niiranen, Pentti, Hama Nadhom, Michal Zanáška, Robert Boyd, Mauricio Sortica, Daniel Primetzhofer, Daniel Lundin e Henrik Pedersen. "Biased quartz crystal microbalance method for studies of chemical vapor deposition surface chemistry induced by plasma electrons". Review of Scientific Instruments 94, n.º 2 (1 de fevereiro de 2023): 023902. http://dx.doi.org/10.1063/5.0122143.

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A recently presented chemical vapor deposition (CVD) method involves using plasma electrons as reducing agents for deposition of metals. The plasma electrons are attracted to the substrate surface by a positive substrate bias. Here, we present how a standard quartz crystal microbalance (QCM) system can be modified to allow applying a DC bias to the QCM sensor to attract plasma electrons to it and thereby also enable in situ growth monitoring during the electron-assisted CVD method. We show initial results from mass gain evolution over time during deposition of iron films using the biased QCM and how the biased QCM can be used for process development and provide insight into the surface chemistry by time-resolving the CVD method. Post-deposition analyses of the QCM crystals by cross-section electron microscopy and high-resolution x-ray photoelectron spectroscopy show that the QCM crystals are coated by an iron-containing film and thus function as substrates in the CVD process. A comparison of the areal mass density given by the QCM crystal and the areal mass density from elastic recoil detection analysis and Rutherford backscattering spectrometry was done to verify the function of the QCM setup. Time-resolved CVD experiments show that this biased QCM method holds great promise as one of the tools for understanding the surface chemistry of the newly developed CVD method.

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Bai, Qingsong, e Xianhe Huang. "Using Quartz Crystal Microbalance for Field Measurement of Liquid Viscosities". Journal of Sensors 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/7580483.

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The field measurement of liquid viscosities, especially the high viscous liquids, is challenging and often requires expensive equipment, long processing time, and lots of reagent. We use quartz crystal microbalances (QCMs) operating in solution which are also sensitive to the viscosity and density of the contacting solution. QCMs are typically investigated for sensor applications in which one surface of QCM completely immersed in Newtonian liquid, but the viscous damping in liquids would cause not only large frequency shifts but also large losses in the quality factorQleading to instability and even cessation of oscillation. A novel mass-sensitivity-based method for field measurement of liquid viscosities using a QCM is demonstrated in this paper and a model describing the influence of the liquid properties on the oscillation frequency is established as well. Two groups of verified experiments were performed and the experimental results show that the presented method is effective and possesses potential applications.

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Lord, Nick, Francois Guenard e Patricia Hug. "QCM Mathematiques". Mathematical Gazette 76, n.º 477 (novembro de 1992): 422. http://dx.doi.org/10.2307/3618412.

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DUCHEYRON, D. "Autoévaluation/QCM". Réanimation 17, n.º 8 (dezembro de 2008): 823–24. http://dx.doi.org/10.1016/j.reaurg.2008.09.013.

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du Cheyron, D. "Autoévaluation/QCM☆". Réanimation 18, n.º 8 (dezembro de 2009): 742–43. http://dx.doi.org/10.1016/j.reaurg.2009.09.003.

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43

Yang, Mingqing, e Junhui He. "A copper–manganese composite oxide as QCM sensing layers for detection of formaldehyde gas". RSC Advances 8, n.º 1 (2018): 22–27. http://dx.doi.org/10.1039/c7ra11427c.

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Copper–manganese composite oxide functionalized QCM resonators were fabricated and explored for HCHO. The liner equation between the response of QCM and HCHO concentration endows the QCM resonators with a capability of HCHO quantitative analysis.

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44

Triyana, Kuwat, Agustinus Sembiring, Aditya Rianjanu, Shidiq Hidayat, Riowirawan Riowirawan, Trisna Julian, Ahmad Kusumaatmaja, Iman Santoso e Roto Roto. "Chitosan-Based Quartz Crystal Microbalance for Alcohol Sensing". Electronics 7, n.º 9 (8 de setembro de 2018): 181. http://dx.doi.org/10.3390/electronics7090181.

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Short-chain alcohols are a group of volatile organic compounds (VOCs) that are often found in workplaces and laboratories, as well as medical, pharmaceutical, and food industries. Real-time monitoring of alcohol vapors is essential because exposure to alcohol vapors with concentrations of 0.15–0.30 mg·L−1 may be harmful to human health. This study aims to improve the detection capabilities of quartz crystal microbalance (QCM)-based sensors for the analysis of alcohol vapors. The active layer of chitosan was immobilized onto the QCM substrate through a self-assembled monolayer of L-cysteine using glutaraldehyde as a cross-linking agent. Before alcohol analysis, the QCM sensing chip was exposed to humidity because water vapor significantly interferes with QCM gas sensing. The prepared QCM sensor chip was tested for the detection of four different alcohols: n-propanol, ethanol, isoamyl alcohol, and n-amyl alcohol. For comparison, a non-alcohol of acetone was also tested. The prepared QCM sensing chip is selective to alcohols because of hydrogen bond formation between the hydroxyl groups of chitosan and the analyte. The highest response was achieved when the QCM sensing chip was exposed to n-amyl alcohol vapor, with a sensitivity of about 4.4 Hz·mg−1·L. Generally, the sensitivity of the QCM sensing chip is dependent on the molecular weight of alcohol. Moreover, the developed QCM sensing chips are stable after 10 days of repeated measurements, with a rapid response time of only 26 s. The QCM sensing chip provides an alternative method to established analytical methods such as gas chromatography for the detection of short-chain alcohol vapors.

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45

Hu, Yufeng, Hanwen Xing, Gang Li e Minghuo Wu. "Magnetic Imprinted Polymer-Based Quartz Crystal Microbalance Sensor for Sensitive Label-Free Detection of Methylene Blue in Groundwater". Sensors 20, n.º 19 (25 de setembro de 2020): 5506. http://dx.doi.org/10.3390/s20195506.

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Tiny changes in the mass of the sensor in a quartz crystal microbalance with dissipation monitoring (QCM-D) can be observed. However, the lack of specificity for target species has hindered the use of QCM-D. Here, molecularly imprinted polymers (MIPs) were used to modify a QCM-D sensor to provide specificity. The MIPs were formed in the presence of sodium dodecyl benzene sulfonate. Imprinted layers on Fe3O4 nanoparticles were formed using pyrrole as the functional monomer and cross-linker and methylene blue (MB) as a template. The MIPs produced were then attached to the surface of a QCM-D sensor. The MIPs-coated QCM-D sensor could recognize MB and gave a linear response in the concentration range 25 to 1.5 × 102 µg/L and a detection limit of 1.4 µg/L. The QCM-D sensor was selective for MB over structural analogs. The MIPs-coated QCM-D sensor was successfully used to detect MB in river water and seawater samples, and the recoveries were good. This is the first time MB has been detected using a QCM-D sensor. Mass is an intrinsic property of matter, so this method could easily be extended to other target species by using different MIPs.

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Zhou, Zhen, Xiaoyu Zhang, Tiean Zhou, Fushen Huang e Jinjun Chen. "Quartz Crystal Microbalance Technology Coupled with Impedance for the Dynamic Monitoring of the Cardiomyocyte Beating Function and Drug Screening". Biosensors 13, n.º 2 (28 de janeiro de 2023): 198. http://dx.doi.org/10.3390/bios13020198.

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The main sensing techniques used to study myocardial pulsation are electrical impedance sensing (EIS) and by quartz crystal microbalance (QCM). While electrical impedance technology is the gold standard for the study of myocardial pulsation, the clinical application of drugs is being followed up in real time additionally, thus, QCM technology needs to be further developed as a very important class of quality sensor technology. Moreover, the application of EIS, in combination with the QCM, for monitoring myocardial pulsation, has been rarely reported. In this paper, a series of cell growth and adhesion conditions were optimized using rat primary cardiomyocytes, and QCM was used in combination with EIS to monitor the adhesion and the myocardial pulsation ability of the cells in real time. Furthermore, cardiomyocytes that adhered to the QCM and EIS were treated with isoprenaline (ISO), a positive inotropic drug, and verapamil (VRP), a negative inotropic drug. Next, the cell index (CI)-time (T) plots, beating amplitude (BA) and beating rate (BR) of the cardiomyocytes were calculated and changes in these parameters, before and after, dosing were evaluated. The results showed that the QCM technique results were not only consistent with the results obtained with EIS, but also that the QCM technique had a certain degree of sensitivity for the calculation of cardiomyocyte beating. Thus, our findings validate the reliability and validity of the QCM technique for measuring cardiomyocyte beating and drug testing. We hope that further studies would evaluate the application of the QCM technology for clinical use.

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Humairah, Nur Aisyah, Fadlunisa Fadlunisa, Kiki Amalia Histhiningtyas, Innas Amaliya Fatyadi, Roto Roto, Ahmad Kusumaatmaja e Kuwat Triyana. "Molecular Imprinting Polymer-Based QCM Sensor for Detection of α-Pinene". Key Engineering Materials 840 (abril de 2020): 418–23. http://dx.doi.org/10.4028/www.scientific.net/kem.840.418.

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The quartz crystal microbalance (QCM) modified by chitosan/α-pinene, prepared by spin-coating technique has been successfully developed with molecular imprinting polymer (MIP) concept. To remove the template, we carried out two treatments namely heating and vacuum in a desiccator. To find out selectivity of the sensor, the QCM modified with polymer chitosan has been tested with another analyte such as acetone, ethanol, N-amyl alcohol, iso-amyl alcohol. The result shows that chitosan/α-pinene coated QCM sensor can provide a good response as good as sensitivity. The best QCM at heating treatment in a furnace with the decline of frequency is 32 Hz, then the QCM vacuum pumping treatment with decline frequency is 27 Hz.

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Regmi, Bishnu P., Puspa L. Adhikari e Beni B. Dangi. "Ionic Liquid-Based Quartz Crystal Microbalance Sensors for Organic Vapors: A Tutorial Review". Chemosensors 9, n.º 8 (27 de julho de 2021): 194. http://dx.doi.org/10.3390/chemosensors9080194.

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Organic vapor sensors are used in diverse applications ranging from environmental monitoring to biomedical diagnostics. Among a number of these sensors, quartz crystal microbalance (QCM) sensors prepared by coating ionic liquids (ILs) or their composites are promising devices for the analysis of volatile organic compounds (VOCs) in complex chemical mixtures. Ionic liquids are remarkable materials, which exhibit tunable physico-chemical properties, chemical and thermal stability, multiple interactions with diverse group of molecules, and enormous structural variability. Moreover, ILs exhibit viscoelastic properties, and hence these materials are ideal for creation of QCM virtual sensor arrays. While the scientific literature on IL-coated QCM sensors is rapidly growing, there is still much to learn. This manuscript provides a comprehensive review on the development of IL-coated QCM sensors and multi-sensor arrays as well as their applications for the analysis of VOCs in complex mixtures. Furthermore, IL-coated QCM virtual sensor arrays and their applications are presented. A short overview of some of the QCM designs, future research areas, and recommendations are also discussed. This short review is a necessary first step towards standardization and further development of QCM for the analysis of VOCs.

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Ummah, Auliya Rahmatul, Imam Tazi e Muthmainnah Muthmainnah. "QCM SENSOR SENSITIVITY ANALYSIS OF SILVER ELECTRODES COATED WITH LIPID MEMBRANE OLEYL ALCOHOL TOWARD NaCl AND HCl". Jurnal Neutrino 11, n.º 2 (17 de setembro de 2019): 65. http://dx.doi.org/10.18860/neu.v11i2.6597.

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<p>One of the sensors, which is currently being developed is the QCM sensor. The QCM sensor is a sensor that utilizes the frequency change to detect a change in mass due to a test substance. The use of a QCM sensor includes other forms of electronic tongue sensor that can distinguish five basic flavours on the tongue. QCM sensor can also be varied electrodes using various lipid membranes such as electronic tongues to increase sensor sensitivity. This research aims to determine the sensitivity of the QCM sensor before and after coated with the lipid membrane to NaCl and HCl. The sensitivity of the QCM sensor to NaCl is 1.47 Hz/M for uncoated sensor and 0.63 Hz/M for coated sensor, while the sensitivity of HCl is 4.55 Hz/M for uncoated sensor and 4.93 Hz/M for coated sensor. The difference of the results is caused by the nature of ionization of the compound and the amount of concentration used. The result of the sensitivity research shows that the QCM sensor with Oleyl Alcohol lipid membrane is more sensitive to HCl than NaCl.</p>

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Naranda, Jakob, Matej Bračič, Matjaž Vogrin, Uroš Maver e Teodor Trojner. "Practical Use of Quartz Crystal Microbalance Monitoring in Cartilage Tissue Engineering". Journal of Functional Biomaterials 13, n.º 4 (21 de setembro de 2022): 159. http://dx.doi.org/10.3390/jfb13040159.

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Quartz crystal microbalance (QCM) is a real-time, nanogram-accurate technique for analyzing various processes on biomaterial surfaces. QCM has proven to be an excellent tool in tissue engineering as it can monitor key parameters in developing cellular scaffolds. This review focuses on the use of QCM in the tissue engineering of cartilage. It begins with a brief discussion of biomaterials and the current state of the art in scaffold development for cartilage tissue engineering, followed by a summary of the potential uses of QCM in cartilage tissue engineering. This includes monitoring interactions with extracellular matrix components, adsorption of proteins onto biomaterials, and biomaterial–cell interactions. In the last part of the review, the material selection problem in tissue engineering is highlighted, emphasizing the importance of surface nanotopography, the role of nanofilms, and utilization of QCM as a “screening” tool to improve the material selection process. A step-by-step process for scaffold design is proposed, as well as the fabrication of thin nanofilms in a layer-by-layer manner using QCM. Finally, future trends of QCM application as a “screening” method for 3D printing of cellular scaffolds are envisioned.

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