Modeling and Experimental Study of Bulk Acoustic Wave Resonator Sensor

Bulk acoustic wave (BAW) resonator as one of the simplest acoustic device, has been proven a most powerful tool for sensor applications with the advantage of precise frequency counting in electronic measurement. Meanwhile, with the improvement of device fabrication and material growth techniques, the resonator can be made with very small size, especially thin film bulk acoustic wave resonators (FBARs) based on ZnO and AlN have been attracted much interest for sensor application due to their high sensitivity induced by high resonance frequency. In this thesis, research focus is on the modeling and experimental study of bulk acoustic wave resonator sensor.Quartz thickness shear mode (TSM) resonator is adopted to characterize the viscoelastic properties of polymer nanocomposite thin films deposited on the resonators surface. The input electric admittance of multilayer loaded TSM acoustic wave resonator is firstly derived using transfer matrix method by taking into account the acoustic wave impedance of the polymeric layer. Nanocomposite thin films of multi-wall carbon nanotubes (MWCNTs) in copolymers of polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) are deposited on TSM resonators through spin-on coating processing. The electric impedance spectra of the unloaded and loaded acoustic wave resonators are measured experimentally, and a data fitting approach is applied to extract the properties of the polymer nanocomposites films. It has been found that the thickness of the polymer layer plays a very important role in the extraction of the viscoelastic properties of the films through data fitting, and the reinforcement of the elastic shear modulus of polymer nanocomposite films is not significant. Quartz TSM resonator is also investigated for in-situ and real time detection of liquid flow rate. A 5MHz TSM quartz resonator is edge-bonded to the sensor mounting port of a special flow chamber with one side exposed to the flowing liquid and other side exposed to air. The fundamental, 3rd, 5th, 7th, and 9th resonant frequency shift due to flow pressure is found to be around 920 (Hz), 3572 (Hz), 5947 (Hz), 8228 (Hz) and 10300 (Hz) for flow rate variation from 0 to 3000 ml/min, which has a corresponding Reynolds number change from 0 to 822. Both theoretical and experimental investigation shows the resonant frequency shifts of different modes are quadratic with flow rate. The results indicate that quartz TSM resonators can be used for flow sensors with characteristics of simplicity, fast response, and good repeatability.FBARs based on c-axis tilted ZnO and AlN thin films have been theoretically analyzed. Material properties including elastic, dielectric and piezoelectric coefficients, bulk wave properties including acoustic velocity and electromechanical coupling coefficient, and impedance of FBARs are calculated and show strong dependence on the tilt angle of c-axis(¦È).Besides ¦È=90¡ã pure thickness shear mode occurs at 43¡ãfor ZnO and 46.1¡ãfor AlN, besides ¦È=0¡ã pure thickness longitudinal mode occurs at 65.4¡ã for ZnO and 67.1¡ãfor AlN. The electromechanical coupling coefficient of shear mode has a maximum value 13.1% at ¦È=33.3¡ãfor ZnO, and 6.5% at ¦È=34.5¡ãfor AlN; the maximum electromechanical coupling coefficient of longitudinal mode occurs at ¦È=0¡ãwith a value of 8.5% for ZnO, and 6% for AlN. The simulation results show that c-axis tilted ZnO and AlN thin films can provide more options for filter design and sensor application

On how zero-knowledge proof blockchain mixers improve, and worsen user privacy

One of the most prominent and widely-used blockchain privacy solutions are zero-knowledge proof (ZKP) mixers operating on top of smart contract-enabled blockchains. ZKP mixers typically advertise their level of privacy through a so-called anonymity set size, similar to k-anonymity, where a user hides among a set of $k$ other users. In reality, however, these anonymity set claims are mostly inaccurate, as we find through empirical measurements of the currently most active ZKP mixers. We propose five heuristics that, in combination, can increase the probability that an adversary links a withdrawer to the correct depositor on average by 51.94% (108.63%) on the most popular Ethereum (ETH) and Binance Smart Chain (BSC) mixer, respectively. Our empirical evidence is hence also the first to suggest a differing privacy-predilection of users on ETH and BSC. We further identify 105 Decentralized Finance (DeFi) attackers leveraging ZKP mixers as the initial funds and to deposit attack revenue (e.g., from phishing scams, hacking centralized exchanges, and blockchain project attacks). State-of-the-art mixers are moreover tightly intertwined with the growing DeFi ecosystem by offering ``anonymity mining'' (AM) incentives, i.e., mixer users receive monetary rewards for mixing coins. However, contrary to the claims of related work, we find that AM does not always contribute to improving the quality of an anonymity set size of a mixer, because AM tends to attract privacy-ignorant users naively reusing addresses

Characterization of thick film piezoelectric lead zirconate titanate (PZT) ceramics fabricated by tape casting processing

Conference Name:2013 IEEE International Ultrasonics Symposium, IUS 2013. Conference Address: Prague, Czech republic. Time:July 21, 2013 - July 25, 2013.Microstructures and electrical properties of PZT thick films fabricated by using a tape casting processing have been studied. The PZT thick film elements sintered at 1250-1300 °C. The PZT thick film obtained shows a uniform grain size and very dense microstructure with minimal pores and better than most of the screen-printed film reported before. A piezoelectric constant d31 of about -181pm/V was derived from the measurement of a unimorph actuator (23μm PZT/110μm stainless steel foil), which was very close the measurement results of thicker films. This proves that PZT films can be fabricated down to tens of micrometer with similar piezoelectric coefficients to bulk ceramics. The characterization results show tape-casting processing can be used to fabricate high quality PZT thick film resonators, and the extracted material constants can be used for sensor, actuator and transducer design. ? 2013 IEEE

Assessing perceived participation among older adults total hip arthroplasty and total knee arthroplasty patients six months post-surgery: a cross-sectional study

AimsThis research sought to assess the perceived levels of participation and autonomy in senior patients who had received total hip arthroplasty (THA) or total knee arthroplasty (TKA) in Hangzhou, China. Furthermore, the study aimed to identify the factors linked to these outcomes.Study designThis investigation will utilize a cross-sectional study design to assess perceived participation and autonomy among older adults total hip arthroplasty (THA) and total knee arthroplasty (TKA) patients. The research was conducted in Hangzhou, China, at a tertiary hospital.MethodsConvenient sampling was utilized to select 139 patients who underwent THA or TKA between March 2022 and March 2023 and met the inclusion criteria at a tertiary hospital in Hangzhou. The Impact on Participation and Autonomy Questionnaire, Hip/Knee Injury and Osteoarthritis Outcome Score (HOOS/KOOS), 5-Item Geriatric Depression Scale, Multidimensional Scale of Perceived Social Support, and Elders Health Empowerment Scale were used to assess perceived participation, hip/knee-related symptoms and functional restrictions, depression symptoms, social support, and health empowerment.ResultsThe mean score for perceived participation and autonomy was 22.554 (SD: 13.042). The mean scores for participation in indoor autonomy, outdoor autonomy, family roles, and social relations were 0.654 (SD: 0.608), 1.324 (SD: 0.792), 1.053 (SD: 0.657), and 0.664 (SD: 0.542), respectively. Negative correlations were observed between perceived participation/autonomy scores and HOOS/KOOS, social support, and health empowerment scores. Conversely, a positive correlation was found between perceived participation/autonomy scores and depression scores. The detrimental effect of HOOS/KOOS, social support, and health empowerment scores on perceived participation and autonomy was notable, while the impact of depressive symptoms was comparatively minor.ConclusionOlder Chinese patients, at first six months post THA/TKA surgery, reported higher levels of perceived participation compared to individuals with other conditions, such as stroke patients. Functional limitations resulting from hip/knee-related symptoms, as well as social support and health empowerment, emerged as significant influencing factors for perceived participation and autonomy. This research enhances our comprehension of the elements influencing perceived participation among older adults individuals who have undergone THA/TKA procedures

Comparative studies of salinomycin-loaded nanoparticles prepared by nanoprecipitation and single emulsion method

To establish a satisfactory delivery system for the delivery of salinomycin (Sal), a novel, selective cancer stem cell inhibitor with prominent toxicity, gelatinase-responsive core-shell nanoparticles (NPs), were prepared by nanoprecipitation method (NR-NPs) and single emulsion method (SE-NPs). The gelatinase-responsive copolymer was prepared by carboxylation and double amination method. We studied the stability of NPs prepared by nanoprecipitation method with different proportions of F68 in aqueous phase to determine the best proportion used in our study. Then, the NPs were prepared by nanoprecipitation method with the best proportion of F68 and single emulsion method, and their physiochemical traits including morphology, particle size, zeta potential, drug loading content, stability, and in vitro release profiles were studied. The SE-NPs showed significant differences in particle size, drug loading content, stability, and in vitro release profiles compared to NR-NPs. The SE-NPs presented higher drug entrapment efficiency and superior stability than the NR-NPs. The drug release rate of SE-NPs was more sustainable than that of the NR-NPs, and in vivo experiment indicated that NPs could prominently reduce the toxicity of Sal. Our study demonstrates that the SE-NPs could be a satisfactory method for the preparation of gelatinase-responsive NPs for intelligent delivery of Sal

Autophagy Inhibition Enhances Daunorubicin-Induced Apoptosis in K562 Cells

Anthracycline daunorubicin (DNR) is one of the major antitumor agents widely used in the treatment of myeloid leukemia. Unfortunately, the clinical efficacy of DNR was limited because of its cytotoxity at high dosage. As a novel cytoprotective mechanism for tumor cell to survive under unfavorable conditions, autophagy has been proposed to play a role in drug resistance of tumor cells. Whether DNR can activate to impair the sensitivity of cancer cells remains unknown. Here, we first report that DNR can induce a high level of autophagy, which was associated with the activation of extracellular signal-regulated kinase 1/2 (ERK1/2). Moreover, cell death induced by DNR was greatly enhanced after autophagy inhibition by the pharmacological inhibitor chloroquine (CQ) and siRNAs targeting Atg5 and Atg7, the most important components for the formation of autophagosome. In conclusion, we found that DNR can induce cytoprotective autophagy by activation of ERK in myeloid leukemia cells. Autophagy inhibition thus represents a promising approach to improve the efficacy of DNR in the treatment of patients with myeloid leukemia

Effects of the interactions between platelets with other cells in tumor growth and progression

It has been confirmed that platelets play a key role in tumorigenesis. Tumor-activated platelets can recruit blood cells and immune cells to migrate, establish an inflammatory tumor microenvironment at the sites of primary and metastatic tumors. On the other hand, they can also promote the differentiation of mesenchymal cells, which can accelerate the proliferation, genesis and migration of blood vessels. The role of platelets in tumors has been well studied. However, a growing number of studies suggest that interactions between platelets and immune cells (e.g., dendritic cells, natural killer cells, monocytes, and red blood cells) also play an important role in tumorigenesis and tumor development. In this review, we summarize the major cells that are closely associated with platelets and discuss the essential role of the interaction between platelets with these cells in tumorigenesis and tumor development

Antioxidant Properties and Correlation with Chemical Components in Selenium-Enriched Rape Powder

This work aims to study the in vitro antioxidant activity of selenium-enriched rape powder extract and its correlation with basic chemical components. The results showed that compared with regular rape powder extract, selenium-enriched rape powder extract contained more nitrogen compounds, polyphenols, flavonoids, total selenium and polysaccharide-bound selenium, and had higher Fe3+ reducing power, 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation, and hydroxyl free radical scavenging activity. Correlation analysis showed that the antioxidant activity was positively correlated with nitrogen compounds, total sugar, polyphenols, flavonoids, saponins, polysaccharides, total selenium, and polysaccharide-bound selenium. Partial correlation analysis showed that the antioxidant activity was only significantly or highly significantly positively correlated with polysaccharides and polysaccharide-bound selenium, which indicated that the difference in antioxidant activity between the two rape powder extracts may be mainly caused by the differences in polysaccharides and polysaccharide-bound selenium contents. In conclusion, there are differences in the basic chemical compositions of selenium-enriched and regular rape powder extracts, and selenium-enriched rape powder extract has a higher in vitro antioxidant activity. Polysaccharide-bound selenium was the major antioxidant component

Resolving the genetic paradox of invasions: Preadapted genomes and postintroduction hybridization of bigheaded carps in the Mississippi River Basin

The genetic paradox of biological invasions is complex and multifaceted. In particular, the relative role of disparate propagule sources and genetic adaptation through postintroduction hybridization has remained largely unexplored. To add resolution to this paradox, we investigate the genetic architecture responsible for the invasion of two invasive Asian carp species, bighead carp (Hypophthalmichthys nobilis) and silver carp (H. molitrix) (bigheaded carps) that experience extensive hybridization in the Mississippi River Basin (MRB). We sequenced the genomes of bighead and silver carps (~1.08G bp and ~1.15G bp, respectively) and their hybrids collected from the MRB. We found moderate‐to‐high heterozygosity in bighead (0.0021) and silver (0.0036) carps, detected significantly higher dN/dS ratios of single‐copy orthologous genes in bigheaded carps versus 10 other species of fish, and identified genes in both species potentially associated with environmental adaptation and other invasion‐related traits. Additionally, we observed a high genomic similarity (96.3% in all syntenic blocks) between bighead and silver carps and over 90% embryonic viability in their experimentally induced hybrids. Our results suggest intrinsic genomic features of bigheaded carps, likely associated with life history traits that presumably evolved within their native ranges, might have facilitated their initial establishment of invasion, whereas ex-situ interspecific hybridization between the carps might have promoted their range expansion. This study reveals an alternative mechanism that could resolve one of the genetic paradoxes in biological invasions and provides invaluable genomic resources for applied research involving bigheaded carps