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In the practical environment, it is very common for the simultaneous occurrence of base excitation and crosswind. Scavenging the combined energy of vibration and wind with a single energy harvesting structure is fascinating. For this purpose, the effects of the wind speed and random excitation level are investigated with the stochastic averaging method (SAM) based on the energy envelope. The results of the analytical prediction are verified with the Monte-Carlo method (MCM). The numerical simulation shows that the introduction of wind can reduce the critical excitation level for triggering an inter-well jump and make a bi-stable energy harvester (BEH) realize the performance enhancement for a weak base excitation. However, as the strength of the wind increases to a particular level, the influence of the random base excitation on the dynamic responses is weakened, and the system exhibits a periodic galloping response. A comparison between a BEH and a linear energy harvester (LEH) indicates that the BEH demonstrates inferior performance for high-speed wind. Relevant experiments are conducted to investigate the validity of the theoretical prediction and numerical simulation. The experimental findings also show that strong random excitation is favorable for the BEH in the range of low wind speeds. However, as the speed of the incoming wind is up to a particular level, the disadvantage of the BEH becomes clear and evident. [ABSTRACT FROM AUTHOR]

Quasi-zero stiffness (QZS) vibration isolators have been intensively studied due to their importance in isolating low-frequency vibration, but isolating the ultralow frequency vibration and supporting variable mass are still challenging and open research issues. This paper proposes novel QZS isolators with two or three pairs of oblique bars. The distinctive feature of the proposed isolators is the constant QZS and thus it can achieve the isolation of ultralow frequency vibration and the capacity of supporting variable mass. Static and dynamic analyses of the proposed isolators are carried out to obtain the stiffness and displacement transmissibility. The QZS features of the proposed isolators are compared with the QZS isolators with two or three pairs of oblique springs. Prototypes of the proposed isolators with two or three pairs of oblique bars are fabricated and tested to verify the theoretical formulations and the constant QZS feature. The experiment results show that the proposed QZS isolators with constant QZS features have lower transmissibility and can isolate vibration in the frequency of 1–1.5 Hz. The isolators with constant QZS are expected to be used for practical applications in the situations of large amplitude and ultralow frequency vibration, and variable mass loading. [ABSTRACT FROM AUTHOR]

Fluid-conveying pipes are widely used to transfer bulk fluids from one point to another in many engineering applications. They are subject to various excitations from the conveying fluids, the supporting structures, and the working environment, and thus are prone to vibrations such as flow-induced vibrations and acoustic-induced vibrations. Vibrations can generate variable dynamic stress and large deformation on fluid-conveying pipes, leading to vibration-induced fatigue and damage on the pipes, or even leading to failure of the entire piping system and catastrophic accidents. Therefore, the vibration control of fluid-conveying pipes is essential to ensure the integrity and safety of pipeline systems, and has attracted considerable attention from both researchers and engineers. The present paper aims to provide an extensive review of the state-of-the-art research on the vibration control of fluid-conveying pipes. The vibration analysis of fluid-conveying pipes is briefly discussed to show some key issues involved in the vibration analysis. Then, the research progress on the vibration control of fluid-conveying pipes is reviewed from four aspects in terms of passive control, active vibration control, semi-active vibration control, and structural optimization design for vibration reduction. Furthermore, the main results of existing research on the vibration control of fluid-conveying pipes are summarized, and future promising research directions are recommended to address the current research gaps. This paper contributes to the understanding of vibration control of fluid-conveying pipes, and will help the research work on the vibration control of fluid-conveying pipes attract more attention. [ABSTRACT FROM AUTHOR]

We study an asymptotic property of weighted sequences of nonnegative functions which extends and unifies previous results concerned with precise asymptotics. As applications, we prove precise asymptotics for partial sums of independent identically distributed classical, noncommutative and free random variables. [ABSTRACT FROM AUTHOR]

Noises are ubiquitous in nature and can often induce some curious phenomena. In this paper, we investigate the internal signal stochastic resonance (ISSR) phenomenon of a two-component gene regulatory network under the excitation of Lévy noise. Our results reveal that the Lévy noise can induce the periodic oscillation of the protein concentration when the control parameter is close to its bifurcation points. Furthermore, we consider the noise-induced periodic signal as the periodic excitation and study the ISSR phenomenon under the cooperation of the nonlinear system, noise-induced periodic signal and random noise. And we found that there may be a connection between the ISSR phenomenon and the bifurcation mechanism. Besides, we also investigate the effects of different noise parameters on the ISSR phenomenon. The simulation results indicate that there is an optimal interval of the stability index α which can induce the ISSR phenomenon, and the skewness parameter β has a negative correlation with the ISSR phenomenon. Our results may provide a pathway to uncover the positive functional mechanism of noises in complex gene regulatory networks. [ABSTRACT FROM AUTHOR]

Microsampling techniques enable the minimization of blood collection volume from animals and subsequent handling of the blood samples or their derived plasma or serum samples. This offers advantages over conventional large-volume sampling, such as eliminating the need for satellite animals and improving animal welfare aspects, and providing the opportunity for additional assessments in small animals where blood volume constraints limit endpoints. This study evaluated the feasibility of implementation of capillary microsampling (CMS) in a single-dose study in mice with the ultimate goal of enabling its use in toxicology studies. The focus was on the impact of microsampling on toxicokinetic assessment and on the subsequent hematology assessment in the same animal. A seventy (70)-μL blood collection via CMS from the tail vein had a minimal effect on the hematology parameters of mice (strain C57BL/6) in samples taken within 24 h of blood collection. TK parameters were similar in plasma samples collected via CMS and cardiac puncture sampling. A bioanalytical assay was developed which enabled the quantification of concentration of both the parent drug and a metabolite using only 5-μL plasma sample per analysis. Incurred sample reanalysis (ISR), unexpected event investigation, and re-assay were successfully performed on the limited samples (≤ 20 μL) collected from CMS. The results of this study confirmed the feasibility of implementing CMS in regulated mouse toxicity studies and demonstrated that it is possible to eliminate or reduce satellite animals. [ABSTRACT FROM AUTHOR]

A 12bit 250MSPS pipeline analog-to-digital converter (ADC) with serial output interface is presented. The pseudo random digital calibration dithered sub-ADC in first stage is used to lower non-ideal errors and improve the dynamic performance in the high speed ADC. An integrated serial output interface is implemented to convert 12bit parallel data into a differential serial data stream. The pipeline ADC was fabricated with CMOS 180 nm 1.8 V 1P5 M process. The active ADC with the serial output interface consumes a power consumption of 395 mW and occupies an area of 8.0 mm2, where the active area of the interface is 0.75 mm2. The measurement results show that the differential non-linearity and integral non-linearity of the proposed ADC are − 0.22/+ 0.16LSB and − 0.4/+ 0.6LSB, respectively. The spurious free dynamic range and signal-to-noise ratio can get 81.17 dB and 69.92 dB with 20 MHz input signal at full sampling speed. The serial output interface provides an eye height greater than 800 mV for data rates of 4 GHz bits per second with a power of 75 mW. [ABSTRACT FROM AUTHOR]

This paper studies the dynamics of a maglev system around 1:3 resonant Hopf-Hopf bifurcations. When two pairs of purely imaginary roots exist for the corresponding characteristic equation, the maglev system has an interaction of Hopf-Hopf bifurcations at the intersection of two bifurcation curves in the feedback control parameter and time delay space. The method of multiple time scales is employed to drive the bifurcation equations for the maglev system by expressing complex amplitudes in a combined polar-Cartesian representation. The dynamics behavior in the vicinity of 1:3 resonant Hopf-Hopf bifurcations is studied in terms of the controller’s parameters (time delay and two feedback control gains). Finally, numerical simulations are presented to support the analytical results and demonstrate some interesting phenomena for the maglev system. [ABSTRACT FROM AUTHOR]

We first systematically study the multivortex states in mesoscopic superconductors via self-consistent Bogoliubov-de Gennes equations. Our work focuses on how the geometrical symmetry affects the penetration and arrangement of vortices in mesoscopic superconductors and find that the key parameter determining the entrance of the vortex is the current density at the hot spots on the edge of sample. Through determining the spatial distribution of hot spots, the geometrical symmetry of the superconducting sample influences the nucleation and entrance of vortices. Our results propose one possible experimental approach to control and manipulate the quantum states of mesoscopic superconductors with their topological geometries, and they can be easily generalized to the confined superfluids and Bose-Einstein condensates. [ABSTRACT FROM AUTHOR]

During stent development, accurate monitoring of the drug concentration in animal tissues can provide critical information on how the drug is released into the circulation and the surrounding tissues. To establish the relationship between the drug concentration and the distance from the stent to the target tissue, a comprehensive strategy was developed for sample collection, sample homogenization and sample storage as well as sample analysis. This strategy was developed with the analytical chemists and animal surgical specialists working together as a team. The optimized sampling process was designed to yield a representative sample, appropriately located and of an appropriate size. The sampling process was also designed to eliminate the potential for carryover and cross-contamination. During sample processing, the analyte solution was spiked into blank tissues using a sharp needle and a gas-tight syringe to prepare tissue quality control samples. These tissue quality controls were then used to evaluate the stability of the drug in solid tissue and homogenate, the homogenization carryover, the cross-contamination and the recovery of the drug during method validation and to monitor the overall process of drug analysis of the swine tissues. This thorough strategy has been applied to the accurate determination of zotarolimus in swine tissues for regulated toxicology studies. The entire process was controlled, including precise tissue sampling, compound-based tissue homogenization, method validation, and the application of the method to regulated toxicokinetics studies. The results demonstrate that analytical chemistry concepts can be successfully integrated into toxicokinetics studies in order to collect precise samples and obtain meaningful results. The strategy can be applied to similar toxicokinetics studies of locally administrated drugs in tissues. [ABSTRACT FROM AUTHOR]

A widely used statistical method to test for genetic association is the transmission disequilibrium test (TDT) using two parent-proband trios. West et al1 have presented evidence from clinically ascertained ADHD families that children from trios were less likely to have DSM-IV combined subtype ADHD and conduct disorder. They suggest that the exclusion of parent-proband duos could reduce the power of the TDT and similar tests to detect susceptibility genes for this subtype of ADHD. We sought to test this hypothesis in a population-based sample of twin families, while controlling for the effects of other proband and family characteristics in a multivariant logistic regression framework using both latent class and DSM-IV ADHD subtype definitions. For both latent class and DSM-IV defined combined and inattentive ADHD, sex of the proband and comorbid conduct disorder or oppositional defiant disorder, significantly predicted diagnosis. For latent class and DSM-IV defined combined subtype, younger age also significantly predicted ADHD subtype. Latent class and DSM-IV defined combined subtype ADHD with comorbid conduct disorder was significantly less common in children from trios while conduct disorder without ADHD did not differ in frequency between families with zero, one or two participating parents.Molecular Psychiatry (2004) 9, 260-263. doi:10.1038/sj.mp.4001406 [ABSTRACT FROM AUTHOR]

The microsampling workshop generated recommendations pertaining to blood sampling site (venous blood versus capillary blood), when to conduct a bridging study, statistical approaches to establish correlation/concordance and deciding on sample size, opportunities and challenges with patient-centric sampling, and how microsampling technology can enrich clinical drug development. Overall, the goal was to provide clarity and recommendations and enable the broader adoption of microsampling supporting patients' needs, convenience, and the transformation from clinic-centric to patient-centric drug development. The need and adoption of away-from-clinic sampling techniques has become critical to maintain patient safety during the current COVID-19 pandemic. [ABSTRACT FROM AUTHOR]

ND-L02-s0201/BMS-986263 is a lipid nanoparticle (LNP) drug product containing a heat shock protein 47 (HSP47)–specific small interfering ribonucleic acid (siRNA) and being developed for the treatment of liver and idiopathic pulmonary fibrosis. To address immunogenicity-related issues, we developed a robust, fit-for-purpose (FFP) three-tier electrochemiluminescent (ECL) anti-drug antibody (ADA) assay for the detection of antibodies (Abs) generated to surface-exposed components of BMS-986263. The drug was coated directly on plates, and several Abs specific for polyethylene glycol (PEG) and other surface components were tested for use as positive quality controls (QCs). Following selection of a rabbit monoclonal anti-PEG Ab, the assay was optimized, and various method development challenges specific to the modality and pseudo surrogate rabbit control were addressed. Screening, confirmatory, and titer cut points were validated following a statistical evaluation of 41 individual K2EDTA human plasma samples at a minimum required dilution (MRD) of 100. Assay precision, sensitivity, selectivity, drug tolerance, and hook effect were determined for the rabbit Ab prepared in human K2EDTA plasma matrix. The assay was used to interrogate anti-drug Ab (ADA) responses in normal human subjects who were administered 90 mg of the drug intravenously (IV) once every week for 3 weeks in phase I clinical trials. All pre- and post-dose samples were found to be negative for ADA. Based on these results, we concluded that BMS-986263 is not immunogenic. To the best of our knowledge, this work represents the first ADA method developed and reported for an LNP-based drug product. [ABSTRACT FROM AUTHOR]