338 results match your criteria filter time-dependent

Broadband radar invisibility with time-dependent metasurfaces.

Sci Rep 2021 Jul 9;11(1):14187. Epub 2021 Jul 9.

School of Electrical Engineering, Tel Aviv University, 69978, Tel Aviv, Israel.

Concealing objects from interrogation has been a primary objective since the integration of radars into surveillance systems. Metamaterial-based invisibility cloaking, which was considered a promising solution, did not yet succeed in delivering reliable performance against real radar systems, mainly due to its narrow operational bandwidth. Here we propose an approach, which addresses the issue from a signal-processing standpoint and, as a result, is capable of coping with the vast majority of unclassified radar systems by exploiting vulnerabilities in their design. Read More

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SARS-CoV-2: Viral Loads of Exhaled Breath and Oronasopharyngeal Specimens in Hospitalized Patients with COVID-19.

Int J Infect Dis 2021 Jul 6. Epub 2021 Jul 6.

Department of Clinical Pharmacy, Pharmaceutical Institute, Kiel University, Gutenbergstraße 76, 24118 Kiel, Germany. Electronic address:

Background: SARS-CoV-2 seems to be mainly transmissible via respiratory droplets. We compared the time-dependent SARS-CoV-2 viral load in serial pharyngeal swab and exhaled breath (EB) samples of hospitalized COVID-19 patients.

Methods: In this prospective proof of concept study, we examined hospitalized patients initially tested positive for SARS-CoV-2. Read More

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A Fusion Algorithm for Estimating Time-Independent/-Dependent Parameters and States.

Sensors (Basel) 2021 Jun 12;21(12). Epub 2021 Jun 12.

State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China.

Vehicle parameters are essential for dynamic analysis and control systems. One problem of the current estimation algorithm for vehicles' parameters is that: real-time estimation methods only identify parts of vehicle parameters, whereas other parameters such as suspension damping coefficients and suspension and tire stiffnesses are assumed to be known in advance by means of an inertial parameter measurement device (IPMD). In this study, a fusion algorithm is proposed for identifying comprehensive vehicle parameters without the help of an IPMD, and vehicle parameters are divided into time-independent parameters (TIPs) and time-dependent parameters (TDPs) based on whether they change over time. Read More

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Spatial Modeling of Daily PM, NO, and CO Concentrations Measured by a Low-Cost Sensor Network: Comparison of Linear, Machine Learning, and Hybrid Land Use Models.

Environ Sci Technol 2021 07 16;55(13):8631-8641. Epub 2021 Jun 16.

Department of Mechanical Engineering, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.

Previous studies have characterized spatial patterns of pollution with land use regression (LUR) models from distributed passive or filter samplers at low temporal resolution. Large-scale deployment of low-cost sensors (LCS), which typically sample in real time, may enable time-resolved or real-time modeling of concentration surfaces. The aim of this study was to develop spatiotemporal models of PM, NO, and CO using an LCS network in Pittsburgh, Pennsylvania. Read More

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Enhancement for P300-speller classification using multi-window discriminative canonical pattern matching.

J Neural Eng 2021 06 4;18(4). Epub 2021 Jun 4.

College of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin, People's Republic of China.

P300s are one of the most studied event-related potentials (ERPs), which have been widely used for brain-computer interfaces (BCIs). Thus, fast and accurate recognition of P300s is an important issue for BCI study. Recently, there emerges a lot of novel classification algorithms for P300-speller. Read More

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Bivalve haemocyte adhesion, aggregation and phagocytosis: A tool to reckon arsenic induced threats to freshwater ecosystem.

Fish Shellfish Immunol 2021 Jul 9;114:229-237. Epub 2021 May 9.

Department of Zoology, Aquatic Toxicology Laboratory, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, PIN 700019, West Bengal, India. Electronic address:

The freshwater aquifers of the Indo-Gangetic plains support rich biodiversity which is under the threat of arsenic contamination. The filter feeding bivalve mollusc Lamellidens marginalis is a sessile and sentinel resident of these freshwater habitats. In the present study, the classical cell behaviours of adhesion and aggregation were monitored in the circulating haemocytes of the freshwater bivalve under the exposure of sodium arsenite (NaAsO) at sublethal concentrations in controlled laboratory conditions for a maximum time-span of sixteen days. Read More

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Tooth Discoloration Induced by Different Calcium Silicate-Based Cements: A Two-Year Spectrophotometric and Photographic Evaluation in Vitro.

J Clin Pediatr Dent 2021 Apr;45(2):112-116

Objective: Calcium silicate-based cements (CSCs) may lead to coronal staining in young permanent teeth over the time. The purpose of this study was to evaluate and compare the long-term tooth discoloration induced by different CSCs.

Study Design: Ninety freshly-extracted human molars were assigned randomly into 6 groups (n=15/group) according to the CSC used as a pulpotomy material: ProRoot MTA, MTA Angelus, NeoMTA, EndoSequence Putty, Biodentine and Negative control (No cement). Read More

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Plug-in tubes allow tunable oil removal, droplet packing, and reaction incubation for time-controlled droplet-based assays.

Biomicrofluidics 2021 Mar 5;15(2):024108. Epub 2021 Apr 5.

Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA.

Here, we report a unique microfluidic technique that utilizes a membrane filter and plug-in tubes to remove oil and pack water-in-oil droplets for controlled incubation of droplet-based assays. This technique could be modularly incorporated into most droplet-generation devices without a need to alter the original designs. Our results show that removing excess oil to form tightly packed droplets allows for extended and controllable incubation for droplets traveling in microchannels. Read More

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Maximum likelihood-based extended Kalman filter for COVID-19 prediction.

Chaos Solitons Fractals 2021 May 2;146:110922. Epub 2021 Apr 2.

Centre for Smart Health, School of Nursing, The Hong Kong Polytechnic University, Hong Kong, China.

Prediction of COVID-19 spread plays a significant role in the epidemiology study and government battles against the epidemic. However, the existing studies on COVID-19 prediction are dominated by constant model parameters, unable to reflect the actual situation of COVID-19 spread. This paper presents a new method for dynamic prediction of COVID-19 spread by considering time-dependent model parameters. Read More

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Time-dependent soft and hard x-ray measurements using streak and x-ray diode array diagnostic systems.

Rev Sci Instrum 2021 Mar;92(3):033527

Plasma Physics Department, Soreq NRC, Yavne 81800, Israel.

High-temperature, high-density experiments require a simultaneous understanding of temporal and spectral regions. The spectral x-ray streak camera (SXSC) is a new high-temporal-resolution spectral x-ray diagnostic system that allows researchers to differentiate between soft and hard x-ray regions. The diagnostic offers three spectral channels with a wide spectral range, one direct channel that includes a filter and two indirect channels that include both mirrors and filters. Read More

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Model-based analysis and forecast of sleep-wake regulatory dynamics: Tools and applications to data.

Chaos 2021 Jan;31(1):013139

Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802, USA.

Extensive clinical and experimental evidence links sleep-wake regulation and state of vigilance (SOV) to neurological disorders including schizophrenia and epilepsy. To understand the bidirectional coupling between disease severity and sleep disturbances, we need to investigate the underlying neurophysiological interactions of the sleep-wake regulatory system (SWRS) in normal and pathological brains. We utilized unscented Kalman filter based data assimilation (DA) and physiologically based mathematical models of a sleep-wake regulatory network synchronized with experimental measurements to reconstruct and predict the state of SWRS in chronically implanted animals. Read More

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January 2021

A novel fluorescent cardiac imaging system for preclinical intraoperative angiography.

BMC Med Imaging 2021 02 25;21(1):37. Epub 2021 Feb 25.

Medical Physics and Biomedical Engineering Department, School of Medicine, Tehran University of Medical Sciences, 1417613151, Tehran, Iran.

Background: Intraoperative coronary angiography can tremendously reduce early coronary bypass graft failures. Fluorescent cardiac imaging provides an advanced method for intraoperative observation and real-time quantitation of blood flow with high resolution.

Methods: We devised a system comprised of an LED light source, special filters, lenses and a detector for preclinical coronary artery angiography. Read More

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February 2021

The critical importance of mask seals on respirator performance: An analytical and simulation approach.

PLoS One 2021 17;16(2):e0246720. Epub 2021 Feb 17.

Department of Biomedical Engineering, University of Melbourne, Melbourne, Victoria, Australia.

Filtering facepiece respirators (FFRs) and medical masks are widely used to reduce the inhalation exposure of airborne particulates and biohazardous aerosols. Their protective capacity largely depends on the fraction of these that are filtered from the incoming air volume. While the performance and physics of different filter materials have been the topic of intensive study, less well understood are the effects of mask sealing. Read More

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February 2021

Batch Effect Adjustment to Lower the Drug Attrition Rate of MCF-7 Breast Cancer Cells Exposed to Silica Nanomaterial-Derived Scaffolds.

Assay Drug Dev Technol 2021 01;19(1):46-61

Environmental Futures Research Institute, Griffith University, Nathan Campus, Nathan, Australia.

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January 2021

Efficient inference, potential, and limitations of site-specific substitution models.

Virus Evol 2020 Jul 20;6(2):veaa066. Epub 2020 Aug 20.

Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland.

Natural selection imposes a complex filter on which variants persist in a population resulting in evolutionary patterns that vary greatly along the genome. Some sites evolve close to neutrally, while others are highly conserved, allow only specific states, or only change in concert with other sites. On one hand, such constraints on sequence evolution can be to infer biological function, one the other hand they need to be accounted for in phylogenetic reconstruction. Read More

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Effect of surfactin on removal of semi-volatile organic compound: Emphasis on enhanced biofiltration performance.

Environ Res 2021 02 27;193:110532. Epub 2020 Nov 27.

Department of Chemical and Environmental Engineering, Environmental Engineering Program, University of Cincinnati, Cincinnati, OH, USA. Electronic address:

The performance of a lab-scale biotrickling filter (BTF) inoculated with a mixed fungal consortium was investigated for the simultaneous abatement of 2-ethylhexanol; a hydrophobic semi-volatile organic compound (SVOC), and propylene glycol monomethyl ether (PGME). The BTF performance was investigated in the presence of lipopeptide-type biosurfactant, surfactin. The effect of surfactin on the removal efficiency and elimination capacity was examined at stretched inlet loading rates (LR): 1. Read More

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February 2021

Medication errors and risk areas in a critical care unit.

J Adv Nurs 2021 Jan 27;77(1):286-295. Epub 2020 Oct 27.

Nursing Department, University of Valencia, Valencia, Spain.

Aims: The aim of this study was to identify the main medication errors, their causality and the highest risk areas in critical care.

Design: A descriptive, longitudinal and retrospective study.

Methods: We performed a systematic analysis of the prescription, transcription and administration records of 2,634 dose units of medications that were administered to a total of 87 critically ill patients during 2018. Read More

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January 2021

Construction and Validation of a Robust Cancer Stem Cell-Associated Gene Set-Based Signature to Predict Early Biochemical Recurrence in Prostate Cancer.

Dis Markers 2020 9;2020:8860788. Epub 2020 Oct 9.

Xinjiang Medical University, No. 393 Xinyi Road, Urumqi, Xinjiang 830011, China.

Background: Postoperative early biochemical recurrence (BCR) was an essential indicator for recurrence and distant metastasis of prostate cancer (PCa). The aim of this study was to construct a cancer stem cell- (CSC-) associated gene set-based signature to identify a subgroup of PCa patients who are at high risk of early BCR.

Methods: The PCa dataset from The Cancer Genome Atlas (TCGA) was randomly separated into discovery and validation set. Read More

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October 2020

Analysis of a multiple-quantum-dots embedded ring structure for potential optically-controlled quantum switch or spin filter.

Sci Rep 2020 Oct 1;10(1):16280. Epub 2020 Oct 1.

Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, People's Republic of China.

We theoretically study the average current through a ring embedded with multiple quantum dots in each arm subjected to a time-dependent external field. A current resonance band can be observed in a six-quantum-dot system. In the presence of a time-dependent external field, mutual transformation occurs between the resonance band and antiresonance band, indicating an effective optically-controlled quantum switch can be realized in a wider quantum dot's energy regime. Read More

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October 2020

Dynamic K-edge Subtraction Fluoroscopy at a Compact Inverse-Compton Synchrotron X-ray Source.

Sci Rep 2020 06 15;10(1):9612. Epub 2020 Jun 15.

Department of Diagnostic and Interventional Radiology, Munich School of Medicine and Klinikum rechts der Isar, Ismaniger Str. 22, 81675, Munich, Germany.

X-ray fluoroscopy is a commonly applied diagnostic tool for morphological and functional evaluation of the intestine in clinical routine. Acquisition of repetitive X-ray images following oral or rectal application of iodine contrast agent visualizes the time dependent distribution of the contrast medium, and helps to detect for example leakages, tumors or functional disorders. However, movements of the intestine and air trapped inside usually prevent temporal subtraction imaging to be applied to fluoroscopy of the gastrointestinal tract. Read More

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Accumulation and toxicity of multi-walled carbon nanotubes in Xenopus tropicalis tadpoles.

Chemosphere 2020 Oct 24;257:127205. Epub 2020 May 24.

School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China.

Multi-walled carbon nanotubes (MWCNTs), a common nanomaterial widely used and discharged in environment, might exert toxic effects on aquatic animals. In this paper, filter-feeding tadpole of Xenopus tropicalis was selected as bioindicator to study the exposure effects of MWCNTs suspensions of 0.5, 1, 2, 4 and 8 mg/L for 72 h. Read More

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October 2020

Effect on Mortality With Inferior Vena Cava Filters in Patients Undergoing Pulmonary Embolectomy.

Am J Cardiol 2020 04 30;125(8):1276-1279. Epub 2020 Jan 30.

Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan.

In the absence of a randomized controlled trial, it is important to obtain as much evidence as possible by other methods on whether inferior vena cava (IVC) filters reduce mortality in patients who undergo pulmonary embolectomy. Therefore, this retrospective cohort study based data from the National Inpatient Sample 2009 to 2014 was undertaken. We assessed in-hospital all-cause mortality in stable and unstable (in shock or on ventilator support) patients with acute pulmonary embolism who underwent pulmonary embolectomy. Read More

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Extended field investigations of ozone-biofiltration advanced water treatment for potable reuse.

Water Res 2020 Apr 22;172:115513. Epub 2020 Jan 22.

American Water, 1 Water Street, Camden, NJ, 08102, USA.

Recovering and reusing treated wastewater effluent is a sustainable and cost-effective practice for addressing global water sustainability. To date, most potable reuse advanced water treatment (AWT) solutions are based on reverse osmosis (RO), which generates a continuous reject stream of concentrated brine waste. Ozone-biofiltration based solutions have been investigated as a potential alternative for RO. Read More

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A Parallel Multiscale Filter Bank Convolutional Neural Networks for Motor Imagery EEG Classification.

Front Neurosci 2019 26;13:1275. Epub 2019 Nov 26.

Engineering Research Center of Molecular and Neuroimaging, Ministry of Education, School of Life Sciences and Technology, Xidian University, Xi'an, China.

Objective: Electroencephalogram (EEG) based brain-computer interfaces (BCI) in motor imagery (MI) have developed rapidly in recent years. A reliable feature extraction method is essential because of a low signal-to-noise ratio (SNR) and time-dependent covariates of EEG signals. Because of efficient application in various fields, deep learning has been adopted in EEG signal processing and has obtained competitive results compared with the traditional methods. Read More

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November 2019

Comparative toxicity of UV-filter Octyl methoxycinnamate and its photoproducts on zebrafish development.

Sci Total Environ 2020 May 20;718:134546. Epub 2019 Nov 20.

Unit of Toxicology, Department of Zoology, School of Life Sciences, Bharathiar University, Coimbatore 641046, India. Electronic address:

In the present study, we explored the adverse effects of Octyl methoxycinnamate (OMC), and its photoproducts, namely 2-ethylhexanol (2-EH) and 4-methoxybenzaldehyde (4-MBA) on the developmental stages of zebrafish using various biomarkers such as developmental toxicity, oxidative stress, antioxidant response, neurotoxicity and histopathological changes. The 96 h effective concentrations (EC) of OMC, 2-EH and 4-MBA were found to be 64.0, 34. Read More

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Molecular modeling as a design tool for sunscreen candidates: a case study of bemotrizinol.

J Mol Model 2019 Nov 26;25(12):362. Epub 2019 Nov 26.

Laboratório de Planejamento Farmacêutico e Simulação Computacional (LaPFarSC), Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-902, Brazil.

Sunscreen-based photoprotection is an important strategy to prevent photoaging and skin cancer. Among the effective and modern sunscreens, triazine compounds are known as an important class based on their physical-chemical properties, such as photostability and UV broad-spectrum absorption (UVA and UVB). Molecular modeling and quantum mechanical calculations approaches can be helpful to orientate the design of sunscreens. Read More

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November 2019

Exceptional points in classical spin dynamics.

Sci Rep 2019 Nov 25;9(1):17484. Epub 2019 Nov 25.

Materials Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA.

Non-conservative physical systems admit a special kind of spectral degeneracy, known as exceptional point (EP), at which eigenvalues and eigenvectors of the corresponding non-Hermitian Hamiltonian coalesce. Dynamical parametric encircling of the EP can lead to non-adiabatic evolution associated with a state flip, a sharp transition between the resonant modes. Physical consequences of the dynamical encircling of EPs in open dissipative systems have been explored in optics and photonics. Read More

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November 2019

Reduced rovibrational coupling Cartesian dynamics for semiclassical calculations: Application to the spectrum of the Zundel cation.

J Chem Phys 2019 Sep;151(11):114307

Dipartimento di Chimica, Università degli Studi di Milano, via C. Golgi 19, 20133 Milano, Italy.

We study the vibrational spectrum of the protonated water dimer, by means of a divide-and-conquer semiclassical initial value representation of the quantum propagator, as a first step in the study of larger protonated water clusters. We use the potential energy surface from the work of Huang et al. [J. Read More

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September 2019

Thymidylate synthase-catalyzed, tetrahydrofolate-dependent self-inactivation by 5-FdUMP.

Arch Biochem Biophys 2019 10 11;674:108106. Epub 2019 Sep 11.

Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warszawa, Poland. Electronic address:

In view of previous crystallographic studies, N-hydroxy-dCMP, a slow-binding thymidylate synthase inhibitor apparently caused "uncoupling" of the two thymidylate synthase-catalyzed reactions, including the N-methylenetetrahydrofolate one-carbon group transfer and reduction, suggesting the enzyme's capacity to use tetrahydrofolate as a cofactor reducing the pyrimidine ring C(5) in the absence of the 5-methylene group. Testing the latter interpretation, a possibility was examined of a TS-catalyzed covalent self-modification/self-inactivation with certain pyrimidine deoxynucleotides, including 5-fluoro-dUMP and N-hydroxy-dCMP, that would be promoted by tetrahydrofolate and accompanied with its parallel oxidation to dihydrofolate. Electrophoretic analysis showed mouse recombinant TS protein to form, in the presence of tetrahydrofolate, a covalently bound, electrophoretically separable 5-fluoro-dUMP-thymidylate synthase complex, similar to that produced in the presence of N-methylenetetrahydrofolate. Read More

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October 2019

Calcium chloride enhances the delivery of exosomes.

PLoS One 2019 22;14(7):e0220036. Epub 2019 Jul 22.

Division of Cardiology, Yonsei University College of Medicine, Seoul, Republic of Korea.

Exosomes might have an unimproved potential to serve as effective delivery vehicles. However, when exosomes are developed for therapeutic applications, a method to enhance their delivery is important. This study aimed to evaluate wheather calcium chloride (CaCl2) or other chloride compounds could enhance exosome delivery to various cells without causing toxicity. Read More

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February 2020