A comparative study and assessment of Doppler ultrasound spectral estimation techniques. Part I: Estimation methods

When compared to the classical Discrete Fourier Transform (DFT) or Fast Fourier Transform (FFT) approach, modern estimation methods offer the potential for achieving significant improvements in estimating the power density spectrum of Doppler ultrasound signals. Such improvements, for example, might enable minor flow disturbances to be detected, thereby improving the sensitivity in arterial disease assessment. Specifically, reduction in the variance and bias can be achieved, and this may enable disturbed flow to be detected in a more sensitive manner. The approach taken here, is to consider spectral estimation methods as a problem of fitting an assumed model to the Doppler signal. The models described assume that the signal is stationary. Since the Doppler signal is generally nonstationary, it is assumed that a short enough time window interval can be chosen over which the signal can be considered stationary. We shall review the various methods and when appropriate, relate them to the nature of the Doppler signal.     

Development of methods to analyse transcranial Doppler ultrasound signals recorded in microgravity

During space flights, several clinical syndromes may be the result of changes in cerebral circulation. The purpose of the paper is to describe the development and initial evaluation of a system for recording, processing and displaying transcranial Doppler ultrasound (TCD) waveforms from the middle cerebral artery (MCA) in microgravity. Volunteers were repeatedly subjected to 15–20 s intervals of microgravity (‘near zero gravity’) during flights on the KC-135 military aircraft. Continuous TCD recordings from the MCA were stored on magnetic tape. The paper describes the system that was developed to digitise the Doppler ultrasound data and markers that corresponded to the various levels of microgravity, obtain the maximum and mean Doppler waveforms, identify the waveforms and quantify them. The results demonstrate the feasibility of making TCD recordings in a microgravity environment and illustrate excellent performance of the system and its ease of operation. Quantitative waveform analysis of the recordings from the first subject studied in the supine position showed statistically significant changes in MCA velocity waveforms during microgravity.     

Helicobacter pylori infection in laryngeal diseases

Clinical studies have shown that Helicobacter pylori can be found not only in the mucosa of the stomach, but in the pharyngeal and laryngeal regions as well. The aim of this prospective case-control study was to identify H. pylori infection in the biopsy material from the larynx of the patients suffering from benign laryngeal diseases (vocal fold polyps, laryngitis) and laryngeal cancer and to investigate the possible relationships between the laryngeal H. pylori and patients’ socio-demographic data and laryngopharyngeal reflux. The results of the biopsy material from 67 adult patients treated for benign laryngeal diseases and laryngeal cancer and 11 individuals of the control group revealed that H. pylori infection could be identified in more than one-third of the patients. In the majority of cases H. pylori was found in the patients with chronic laryngitis (45.5 %) and laryngeal cancer (46.2 %). The findings of these sub-groups significantly differed from those of the control group (9.1 %) (p < 0.05). No significant relationships between H. pylori infection found in the laryngeal region and patients’ demographic data, their unhealthy habits and reflux-related symptoms or signs were obtained. It could be concluded that H. pylori can colonize in the larynx of patients with benign laryngeal diseases and laryngeal cancer. To clarify the role of H. pylori as a risk factor for laryngeal diseases further research is needed.     

The Y-box binding protein YB-1 is associated with progressive disease and mediates survival and drug resistance in multiple myeloma

Current knowledge about molecular mechanisms underlying disease progression and drug resistance in multiple myeloma (MM) is still limited. Here, we analyzed the potential pathogenetic role of the Y-box binding protein YB-1 in MM. YB-1 is a member of the cold-shock domain protein superfamily and involved in various cellular functions such as proliferation. Immunohistochemical analyses revealed that neither normal bone marrow (BM) plasma cells (PCs), premalignant PCs of patients with monoclonal gammopathy of unknown significance (MGUS), nor MM cells with a mature morphology showed expression of YB-1 in situ. In contrast, YB-1 was strongly expressed in situ in normal PC precursor blasts as well as in a MM subset and in vitro in all of the evaluated MM cell lines. The YB-1-expressing MM cells were characterized by an immature morphology and a highly proliferative phenotype as defined by Ki 67 expression. We observed that siRNA-mediated knockdown of YB-1 decreased proliferation and induced apoptosis in MM cells even in the presence of BM stromal cells. Furthermore, we found that overexpression of YB-1 mediated resistance toward doxorubicin-induced apoptosis in MM cells. Thus, YB-1 contributes to disease progression, survival, and drug resistance in MM and might therefore provide an attractive therapeutic target.     

Stroke complicating acute myocardial infarction. A meta-analysis of risk modification by anticoagulation and thrombolytic therapy.

BACKGROUND. The objective of this meta-analysis was to examine the impact of systemic anticoagulation and thrombolysis on the total incidence of stroke following myocardial infarction. Additionally, we sought to compare the relative risk of stroke with different thrombolytic agents. METHODS. A computerized and manual literature search for controlled clinical trials of anticoagulants and thrombolytic agents in myocardial infarction reporting on total strokes in treated and control patients was used. Pooling was performed by calculating the Mantel-Haenszel odds ratio and 95% confidence interval (CI). RESULTS. The Mantel-Haenszel pooled odds ratio for anticoagulation trials was 0.46 (95% CI, 0.30 to 0.64), suggesting a benefit of anticoagulant therapy. However, a statistically significant degree of variability (heterogeneity) was present among study results. The odds ratios for all thrombolytic trials, tissue plasminogen activator, and streptokinase trials, respectively, were 1.08 (95% CI, 0.87 to 1.35), 1.28 (95% CI, 0.76 to 2.17), and 1.02 (95% CI, 0.80 to 1.30), suggesting no overall excess of stroke with thrombolysis. The pooled odds ratio for three studies directly comparing streptokinase and tissue plasminogen activator was 0.73 (95% CI, 0.61 to 0.86), suggesting an excess of stroke for patients treated with tissue plasminogen activator in comparison with streptokinase-treated patients. CONCLUSIONS. The available data may support a role for anticoagulants in reducing the incidence of stroke after myocardial infarction, but the heterogeneity among the trials makes interpretation of this effect difficult. Although the available data do not indicate an increase in stroke with thrombolysis, a direct comparison of tissue plasminogen activator and streptokinase reveals an excess of strokes with tissue plasminogen activator.     

Research of Wood Waste as a Potential Filler for Loose-Fill Building Insulation: Appropriate Selection and Incorporation into Polyurethane Biocomposite Foams

Currently, the recycling potential of wood waste (WW) is still limited, and in a resource efficiency approach, recycling WW in insulation materials, such as polyurethane (PUR), appears as an appropriate solution. It is known that the quality of WW is the main aspect which influences the stability of the final products. Therefore, the current study analyses different WW-based fillers as possible modifiers for polyurethane biocomposite foams for the application as loose-fill materials in building envelopes. During the study of WW-based fillers, it was determined that the most promising filler is wood scobs (WS) with a thermal conductivity of 0.0496 W/m·K, short-term water absorption by partial immersion—12.5 kg/m², water vapour resistance—0.34 m²·h·Pa/mg and water vapour diffusion resistance factor—2.4. In order to evaluate the WS performance as a filler in PUR biocomposite foams, different ratios of PUR binder and WS filler (PURb/WS) were selected. It was found that a 0.40 PURb/WS ratio is insufficient for the appropriate wetting of WS filler while a 0.70 PURb/WS ratio produced PUR biocomposite foams with the most suitable performance: thermal conductivity reduced from 0.0523 to 0.0476 W/m·K, water absorption—from 5.6 to 1.3 kg/m², while the compressive strength increased from 142 to 272 kPa and the tensile strength increased from 44 to 272 kPa.     

The optimization of technological processes,stability and microbiological evaluation of innovative natural ingredients-based multiple emulsion

Abstract

For the last couple of decades, multiple emulsions were prepared either by the re-emulsification of primary emulsion or they were produced by an emulsion inversion and their technological peculiarities were widely investigated. The aim of our study was to investigate and determine the optimal technological parameters of innovative multiple emulsion, prepared directly—by addition of ethanolic rosemary extract in the presence of polymeric emulsifier—and evaluate its stability by experimental surface response design approach. The results revealed that simplified W/O/W emulsification process is stirring time and stirring speed sensitive: the change of stirring time from 5 to 15?min at 600?rpm resulted in increased viscosity (from 1705.6?±?62.2 to 3364.1?±?112.5?mPA/s) and smaller oil droplet size (from 33.09?±?1.51 to 17.81?±?0.78?μm), though the conductivity increased from 800?±?2 to 882?±?2 μS/cm (p?<?.05). The second mixing stage (1000?rpm) had a negative effect on the conductivity of W/O/W emulsion because of the inner aqueous phase encapsulation efficiency. Ethanolic rosemary extract was used as multifunctional agent: not only to form multiple emulsion but also to preserve it; microbiological assay confirmed its effectiveness. A stable W/O/W type drug delivery system was successfully created without additional technological stages, phase inversion or surfactants.     

The temporary effect of short-term endotracheal intubation on vocal function

The objective of the study was to assess and perceive the vocal and pharyngeal symptoms and acoustic changes of voice after short-term endotracheal intubation and to evaluate the relation between these changes and the endotracheal tube parameters, number of intubation attempts, duration of anaesthesia, experience of anaesthesiologist. A total of 108 patients were evaluated preoperatively, 1–2 and 24 h after extubation. The vocal and pharyngeal symptoms, voice acoustic characteristics and maximum phonation time (MPT) were evaluated to find the relationship with endotracheal tube parameters, number of intubation attempts, duration of anaesthesia, experience of anaesthesiologist. All vocal and pharyngeal symptoms increased significantly at 24 h and remained significantly increased at 24 h after general anaesthesia. The vocal acoustic parameters changed significantly at 1–2 h: decrease of MPT and increase relative average perturbation were recorded. The day after the short-term intubation: only noise to harmony ratio and habitual pitch remains significantly changed. The most important endotracheal tube parameters that affect significantly (P value <0.05) the vocal function were the size of tube, cuff volume and number of intubation attempts. In relation to the anaesthesia, the changes of the acoustic parameters did not associate significantly with the anaesthesia-related parameters. No statistically significant relationship between experience of an anaesthesiologist and changes of the voice after anaesthesia was detected. Though being short-term, endotracheal anaesthesia is an invasive procedure, and its temporary influence on vocal function is important.