Nano- and microplastics: a comprehensive review on their exposure routes, translocation, and fate in humans.

Contamination of the environment with nano-and microplastic particles (NMPs) and its putative adverse effects on organisms, ecosystems, and human health is gaining increasing scientific and public attention. Various studies show that NMPs occur abundantly within the environment, leading to a high likelihood of human exposure to NMPs. Here, different exposure scenarios can occur.

Using an IT-Based Algorithm for Health Promotion in Temporary Settlements to Improve Migrant and Refugee Health.

The application of the electronic algorithm developed by the Mig-Healthcare project was pilot tested in a sample of migrants and refugees in 2 Reception and Identification Centres (RICs), temporary settlements, in Greece using portable devices. The questions relate to health literacy issues, to mental health, to vaccination history, to lifestyle habits such as smoking, alcohol intake, diet, to the presence of diseases such as heart disease or diabetes, to the use of prevention services and to dental care. A total of 82 adults, 50 women and 32 men, participated.

Intra-arterial chemotherapy is not superior to intravenous chemotherapy for malignant gliomas: a systematic review and meta-analysis.

The efficacy and safety of intra-arterial (IA) chemotherapy versus intravenous (IV) chemotherapy for malignant gliomas were studied. We searched eight electronic databases to identify relevant randomized controlled trials that compared IA chemotherapy with IV chemotherapy in patients with malignant gliomas. This study was conducted in compliance with the Quality of Reporting of Meta-analysis (QUORUM) guidelines.

Dynamic chromatography: A stochastic approach.

During the chromatographic separation process, analyte reactions are often observed leading to band broadening and/or elution of peak clusters. For many different chemical compounds the reaction can be reduced to a simple isomerisation kinetic scheme where elution is the result of adsorption-desorption on the surface stationary phase coupled with a flipping two-level reaction system. In this paper, the chromatographic peak shape for a reacting analyte is calculated in frequency domain when the reaction follows a simple reversible first order scheme.

Intravascular sonotherapy decreases neointimal hyperplasia after stent implantation in swine.

Background: Intimal hyperplasia and subsequent in-stent restenosis remain a major limitation after stent implantation. In vitro cell culture studies show that low-frequency, noncavitational ultrasound energy may impact smooth muscle cell proliferation. Accordingly, we assessed the efficacy of intravascular sonotherapy treatment on intimal hyperplasia in a swine stent model.

Validation of a Doppler guide wire for intravascular measurement of coronary artery flow velocity.

Background: An improved intravascular ultrasonic Doppler device could aid the clinical assessment of coronary hemodynamics. We evaluated a new device consisting of a 12-MHz piezoelectric transducer integrated onto the tip of a 0.018-in.

Instantaneous and continuous cardiac output in humans obtained with a Doppler pulmonary artery catheter.

A new Doppler pulmonary artery catheter was used to measure instantaneous and continuous cardiac output in both an in vitro model and in 44 patients undergoing cardiac catheterization. Cardiac output was calculated with use of the Doppler catheter-determined instantaneous space-average velocity and the ultrasonically determined instantaneous vessel area. Doppler flow and thermodilution were compared with electromagnetic flow in the in vitro model and with Fick cardiac output in patients.

Flow determination using computed tomography: application to aortic dissection. Part II.

Dynamic CT is not only useful in imaging an aortic dissection but may provide additional information concerning the hemodynamic significance of differing flow patterns in the false channel compared with the true channel. Once validated, the computed tomographic (CT) method of flow determination (See Part I) was applied to an experimental animal model with a surgically created aortic dissection. Good correlation was obtained for the flow estimates of cardiac output derived for the true and false channel (r = .

Flow determination using computed tomography: application to aortic dissection. Part I.

The CT method of flow determination evaluated in this study was based on the application of contrast enhancement dynamics. In order to characterize flow, such parameters as mean transit time, rise time, peak CT value, curve width and variance, and others were derived from the venoarterial indicator dilution curves using a perfect mixers-in-series model of curve fitting analysis and a bolus injection of contrast medium. The technique was first validated in a steady state phantom model that simulated in vivo conditions of right-sided mixing closely by the introduction of a number of mixers.

The critical importance of convolution function (algorithm) selection in the measurement of blood flow in small blood vessels by computed tomography scanning.

In order to assess the capability for measuring blood flow in small vessels, the cardiac output was measured directly by either the microsphere reference sample technique or by obtaining blood samples simultaneously with the CT scan. The cardiac output was also measured in vivo by dynamic CT scanning and intravenous contrast as the indicator in an indicator dilution curve. Cardiac output was then calculated by two convolution back projection algorithms which optimized for either contrast or spatial resolution.

Quantitative evaluation of left ventricular function using computed tomography.

Computed tomography (CT) provides a noninvasive technique with high resolution cross-sectional tomographic images which allow volume measurements of an object, independent of its geometric configuration. A phantom of known volume with controllable periodic motion was used to validate the CT method of volume determination. A good correlation (P less than 0.

Variability of myocardial CT measurements in vivo.

Variability of myocardial CT measurements, as indicated by standard deviations of mean CT numbers from four myocardial regions, was compared in 12-second scans, 3-second scans, and gated end-diastolic and end-systolic images, all from the same 12 seconds of scan data, both without and with radiographic contrast enhancement in experimental animals. There were statistically significant differences (P less than 0.05) in standard deviations of myocardial CT measurements when comparing 3-second and 12-second scans without contrast (10.

Measurement of attenuation and scatterer spacing in human liver tissue: preliminary results.

A study measuring two quantitative parameters of human liver in vivo was performed to assess the reliability of measurement of the two parameters, and to evaluate their potential for diagnosing and grading diffuse fibrotic liver disease. The parameters measured were attenuation and "mean scatterer spacing," a measure of tissue structure. Components of variance analysis demonstrated that variation in the measured parameters was a function of the subject being examined, with significant variation noted between data acquisition sessions performed the same day.

Ultrasound attenuation measurements of the liver in vivo using a commercial sector scanner.

Attenuation measurements of various tissue mimicking phantoms and three different groups of patients were obtained using a modified commercial sector scanner. Estimates of attenuation were made using the spectral shift method with mean frequencies at different depths of a region of interest being obtained by both zero crossing and fast Fourier transform techniques. The accuracy and precision of both techniques was compared in phantoms and it was found that the FFT technique yielded less day-to-day variation (SD=3 percent) than the zero crossing technique (5 percent).

Validation of a CT method for flow determination. Work in progress.

The dynamic computed tomographic (DCT) method of flow determination is based on the application of venoarterial indicator dilution curves as they reflect flow. Using a simple model consisting of a tube and a single mixing chamber, experimental parameters were optimized in a controlled manner to achieve ideal mixing for flow determination. Under these ideal conditions, and using 16 consecutive 3-second scans of an 8-mm thick section, tube diameters of 8 mm and 20 mm, and flow range of 0.

Estimation of the slope of the acoustic attenuation coefficient.

In this paper, a theoretical framework is developed which removes the Gaussian assumption commonly used in ultrasonic attenuation estimation based on mean frequency shift. The theory is developed for general non-Gaussian spectra and for media whose attenuation coefficient is nonlinear with frequency. Then, a linear approximation in the estimation of the attenuation coefficient's slope is examined.

Baseline subtraction in quantitative cardiovascular computed tomography.

Beam-hardening (BH) effect was evaluated to determine its potential significance in quantitative blood flow measurements using computed tomography (CT). CT scans of a water bath containing a range of concentrations of iodine (0-15 mg/ml) placed outside and within the chest of a dead dog were obtained at different kVp levels (100, 120, and 130 kVp). The mean CT number and standard deviation were measured over a small region of interest for each concentration.

In vivo stochastic ultrasonic characterisation of abdominal tissues.

Two experimental systems have been used for digitization of waveforms backscattered from normal and pathologic abdominal tissues in vivo. Initial studies were performed with a digitization system which allowed only A-mode display of areas of interest before and during waveform recording. A new interactive system allows for digitization of waveforms from areas of interest in abdominal organs, selected with the aid of real-time B-mode images of a mechanical sector scanner.

Dynamics of myocardial contrast enhancement: an in vivo computed-tomographic study.

Enhancement of normal functioning myocardium was quantitated in 15 dogs by serial computed transmission tomographic (CT) images during the bolus (10 ml/sec.) or slow (1 ml/sec.) intravenous injection of diatrizoate contrast media (1 ml/kg body weight) in concentrations of 37, 18.

Acute myocardial ischemia detected in vivo by computed tomography.

Normal and acutely ischemic myocardium was imaged by dynamic computed transmission tomography (CT) in dogs during injection of contrast material. The rotary fan-beam CT scanner used could obtain 16 sequential, ungated, 3.0-second scans at 13-20-second intervals.

Regional myocardial flow estimation using computed tomography.

A novel method is presented for estimating regional myocardial blood flow (RMBF) using x-ray computed tomography (CT). Two major setbacks are removed from the existing methods; namely, the requirement for intra-arterial bolus injection of tracer, and the inability to determine regional volumes of tracer distribution when the corresponding partition coefficients are unknown. The mathematical model developed for RMBF estimation combines both the tracer dispersion process and the CT measurement process.