Search

This paper presents a collection of lidar-derived aerosol intensive optical properties for several aerosol types, namely the particle linear depolarization ratio, the extinction-to-backscatter ratio (lidar ratio) and the Ångström exponent. The data collection, named DeLiAn, is based on globally distributed, long-term, ground-based, multiwavelength, Raman and polarization lidar measurements, conducted mainly with lidars that have been developed at the Leibniz Institute for Tropospheric Research. The intensive optical properties are presented at two wavelengths, 355 and 532 nm, for 13 aerosol categories. The categories cover the basic aerosol types (i.e., marine, pollution, continental European background, volcanic ash, smoke, mineral dust), as well as the most frequently observed mixtures they form. This extensive collection also incorporates more peculiar aerosol categories, including dried marine aerosol that, compared to marine aerosol, exhibits a significantly enhanced depolarization ratio (up to 15 %). Besides Saharan dust, additional mineral dust types related to their source region were identified due to their lower lidar ratios (Central Asian and Middle Eastern dust). In addition, extreme wildfire events (such as in north America and Australia) emitted smoke into the stratosphere showing significantly different optical properties, i.e., high depolarization values (up to 25 %), compared to tropospheric smoke. The data collection reflects and underlines the variety of aerosol mixtures in the atmosphere and can be used for the development of aerosol-typing schemes. The paper contains the most up-to-date and comprehensive overview of optical properties from aerosol lidar measurements and, therefore, provides a solid basis for future aerosol retrievals in the frame of both spaceborne and ground-based lidars. Furthermore, DeLiAn can assist the efforts for the harmonization of satellite records of aerosol properties performed at different wavelengths.

A global vertically resolved aerosol data set covering more than 10 years of observations at more than 20 measurement sites distributed from 63° N to 52° S and 72° W to 124° E has been achieved within the Raman and polarization lidar network PollyNET. This network consists of portable, remote-controlled multiwavelength-polarization-Raman lidars (Polly) for automated and continuous 24/7 observations of clouds and aerosols. PollyNET is an independent, voluntary, and scientific network. All Polly lidars feature a standardized instrument design with different capabilities ranging from single wavelength to multiwavelength systems, and now apply unified calibration, quality control, and data analysis. The observations are processed in near-real time without manual intervention, and are presented online at http://polly.tropos.de/. The paper gives an overview of the observations on four continents and two research vessels obtained with eight Polly systems. The specific aerosol types at these locations (mineral dust, smoke, dust-smoke and other dusty mixtures, urban haze, and volcanic ash) are identified by their Ångström exponent, lidar ratio, and depolarization ratio. The vertical aerosol distribution at the PollyNET locations is discussed on the basis of more than 55 000 automatically retrieved 30 min particle backscatter coefficient profiles at 532 nm as this operating wavelength is available for all Polly lidar systems. A seasonal analysis of measurements at selected sites revealed typical and extraordinary aerosol conditions as well as seasonal differences. These studies show the potential of PollyNET to support the establishment of a global aerosol climatology that covers the entire troposphere.

This work concerns analysis of turbulence in the atmospheric boundary layer (ABL) shortly before and after sunset. Based on a large set of Doppler lidar measurements at rural and urban sites, we analyze frequency spectra of vertical wind at different heights and show that they increasingly deviate from Kolmogorov's -5/3 prediction in the measured low-wavenumber part of the inertial range. We find that before sunset, the integral length scales tend to decrease with time. These findings contrast with a classical model of equilibrium decay of isotropic turbulence, which predicts that the scaling exponent should remain constant and equal to -5/3 and the integral length scale should increase in time. We explain the observations using recent theories of non-equilibrium turbulence. The presence of non-equilibrium suggests that classical parametrization schemes fail to predict turbulence statistics shortly before sunset. By comparing the classical and the non-equilibrium models, we conclude that the former may underestimate the dissipation rate of turbulence kinetic energy in the initial stages of decay.

Strong events of long-range transported biomass burning aerosol were detected during July 2013 at three EARLINET (European Aerosol Research Lidar Network) stations, namely Granada (Spain), Leipzig (Germany) and Warsaw (Poland). Satellite observations from MODIS (Moderate Resolution Imaging Spectroradiometer) and CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) instruments, as well as modeling tools such as HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory) and NAAPS (Navy Aerosol Analysis and Prediction System), have been used to estimate the sources and transport paths of those North American forest fire smoke particles. A multiwavelength Raman lidar technique was applied to obtain vertically resolved particle optical properties, and further inversion of those properties with a regularization algorithm allowed for retrieving microphysical information on the studied particles. The results highlight the presence of smoke layers of 1–2 km thickness, located at about 5 km a.s.l. altitude over Granada and Leipzig and around 2.5 km a.s.l. at Warsaw. These layers were intense, as they accounted for more than 30 % of the total AOD (aerosol optical depth) in all cases, and presented optical and microphysical features typical for different aging degrees: color ratio of lidar ratios (LR532 ∕ LR355) around 2, α-related ångström exponents of less than 1, effective radii of 0.3 µm and large values of single scattering albedos (SSA), nearly spectrally independent. The intensive microphysical properties were compared with columnar retrievals form co-located AERONET (Aerosol Robotic Network) stations. The intensity of the layers was also characterized in terms of particle volume concentration, and then an experimental relationship between this magnitude and the particle extinction coefficient was established.

We report on importance of conducting comprehensive studies of atmospheric aerosol particles, which cannot be done if information from various complementary sensors is unavailable. We present an example for such application and recommend on the types of sensors that should be used in view of the ACTRIS and RI-URBANS new strategies for monitoring at supersites. Although active and passive remote sensing data was not available in continuous mode, we show that synergic use of them with in-situ observations allows for comprehensive study of temporal and height-resolved distribution of aerosol in the lower troposphere and it can be successfully combined to assess biomass burning impact on air quality and optical properties. The analysed period was divided into three episodes based on the measured black carbon (BC) concentration and the prevailing wind direction. The dominant 72-h backward trajectories were ending in western Europe, mid-Atlantic and western Russia, respectively, The in-situ measured mass concentrations of BCtotal and BC apportioned to biomass burning as well as particulate matter (PM) concentrations in accumulation mode were twice higher during the first and last episodes compared to the second episode, representing long-range transport from different source regions. The obtained complementary surface, column-integrated, and layer-derived size distributions and other parameters demonstrate the added value of multisensor analyses., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

High quality lidar measurements of PollyXT operating at the University of Warsaw in the years 2013-2022 were analyzed to present a comprehensive optical characterization of biomass burning aerosols over Warsaw. The directions of the aerosol inflows were analyzed by dividing advection cases into four types, according to the area of origin: Western Europe, Eastern Europe, the Iberian Peninsula, and North America. It was shown that optical properties of smoke vary in each of these types, and emphasized that aerosol aging processes are important. It was found that as aerosol's age increases, there is more backscattering and less extinction at 355 nm in relation to 532 nm. The analysis of the lidar ratio demonstrated that the main changes of the aging process were observed in the UV spectra.

Objectives: To evaluate the presence and extent of cardiac calcifications and aortic stiffness in patients with end-stage renal disease (ESRD)., Patients and Methods: The study group consisted of 60 patients with ESRD with a mean age of 51.7 years, treated with peritoneal dialysis. In all patients transthoracic echocardiogram was performed to assess the following parameters: left ventricular end-systolic diameter, left ventricular end-diastolic diameter (LVEDd), interventricular septum end-diastolic diameter (IVSDd), posterior wall end-diastolic diameter (PWDd), ejection fraction (EF), fractional shortening (FS), aortic maximal and minimal diameter, aortic valve area, mitral valve area (MVA), left ventricular ejection time (LVET), maximal aortic velocity. Aortic stiffness index (AS) was calculated. Aortic and mitral valve calcifications were assessed., Results: Patients with ESRD had a larger left ventricle (LVEDd 5.4 cm vs. 4.76 cm) and its wall was thicker (IVSDd 1.36 cm vs. 1.02 cm; PWDd 1.31 cm vs. 0.94 cm). Patients had poorer left ventricle contractility (EF 56.1 vs. 61.6%; FS 28.5 vs. 33.2%). Atherosclerotic plaques, calcified plaques and valvular calcifications were more frequently detected in patients with ESRD. Patients with ESRD had significantly higher values of the AS index: (5.34 vs. 3.24). Among ESRD subjects with the stiffer aorta, atherosclerotic plaques including calcificones and the aortic valve damage were more frequently detected., Conclusions: Patients with ESRD are characterized by increased aortic stiffness. Atherosclerotic plaques in the aorta as well as cardiac and large vessels calcifications are more common among patients with ESRD. In patients with ESRD there is a correlation between an increase in aortic stiffness and damage of aortic valvular leaflets as well as calcifications of atherosclerotic plaques in the aorta. The degree of aortic stiffness is not related to impairment of mitral valvular leaflets and extravalvular calcifications. A relationship between aortic stiffness and aortic or aortic valve calcifications suggest a different pathogenesis of aorta calcification as compared to that underlying calcifications of other localizations.

Cardiovascular disease (CVD) is a major cause of death in peritoneal dialysed patients (PD-pts). Coronary artery calcification (CAC) is likely to affect the development of CVD. Purpose of our study was to evaluate coronary artery calcification and risk factors of this calcification in PD-pts. We studied 62 patients (38 F, 24 M) undergoing peritoneal dialysis (PD). Coronary calcification was examined by ECG-gated multidetector CT (Light Speed Ultra) using Agatson (AG) and volumetric (V) methods. Patients were divided into 3 groups depending on mean value of estimated CAC: group A-no calcification, group B-CAC maximal value 400 mm3, group C-CAC value more than 400 mm3. As risk factors of CAC were evaluated: patients age, sex, dialysis duration, serum concentration of Ca, P, homocysteine CRP and fibrinogen, as well as, CaxP product, intact PTH; presence of diabetes or hypertension. Coronary artery calcification was detected in 68% of patients. In the whole observed population positive correlation between CAC determined by AG and V methods and CRP (r = 0.36, p < 0.05) as well as patients age (r = 0.5, p < 0.01) was observed. There was also positive correlation between CAC and fibrinogen concentration (AG CAC r = 0.58, p < 0.05; V CAC r = 0.72, p < 0.05). When compared group C with the groups A and B cardiovascular complications were in this group more frequent than in the last two: 4 patients from group C died because of cardiovascular complications.

The loss of sense of smell significantly decreases a quality of life after total laryngectomy. That is why this problem should be considered within a complex rehabilitation of laryngectomized patients. The smell exercises ought to start parallely to the speech rehabilitation. The aim of our study was to estimate the efficacy of smell rehabilitation after total laryngectomy. 59 persons after total laryngectomy attending the fourteen days long rehabilitation camp were examined. All the patients had the examination of three smells identification (lemon, mint and anise) made before the beginning of exercises. All the persons had also the efficacy of air aspiration through the nose measured. The control examination of those parameters was conducted after fourteen days of exercises of making the negative pressure in the throat and nasopharynx directing the air flow into the olfactory area of the nose. We confirmed a statistically significant differences between the smell identification and the force of aspiration before and after rehabilitation. We confirmed that patient's age and the time from laryngectomy have the influence into the efficacy of smell rehabilitation.

Background: A well-functioning mature arteriovenous fistula is essential for the maintenance of haemodialysis in patients with chronic renal failure. The Brescia-Cimino arteriovenous fistula has the best survival characteristics and low rate of complications. The most common reason of fistula failure is thrombosis caused by stenosis. Colour Doppler ultrasonography has proven to be effective in the assessment of anatomical vascular features. The majority of studies were done in patients with clinically presumed arteriovenous fistula complications. However, only limited data are available about the well-functioning mature arteriovenous fistulas. The purpose of the present study was to evaluate completely asymptomatic, mature arteriovenous fistulas with colour Doppler ultrasound., Materials and Methods: From July 2001 to April 2003, we examined 139 patients with the end-stage renal disease. They were in the range of 19-79 years of age (mean, 46.7 years). The study included only the patients who met the following criteria: (1) no difficulties with haemodialysis (as reported by nurses); (2) normal venous diastolic blood pressure (<150 mmHg) at monthly evaluation; (3) normal urea clearance x time/urea volume of distribution; (4) blood cells count, plasma electrolytes, and liver function at monthly evaluation. The mean fistula age was 26 months (S.D.=21.9). The mean time of dialysis therapy was 49 months. Thirty-eight percent patients had primary fistulas, 23%--secondary, 11%--third and 11%--fourth, 4%--fifth, 5%--sixth, and 8% patients had more than sixth., Results: There was no correlation between: (1) patient's age and fistula age; (2) patient's age and number of fistulas in one patient; (3) fistula age and number of fistulas in one patient; (4) localization of fistula and fistula age. There was a strong correlation between dialysis therapy period and number of fistulas in one patient. The mean flow volume was 1204.1 ml/min (S.D.=554). It was significantly higher in the fistulas with aneurysms, calcifications and tortuous vessels and lower in those with stenosis. There was no correlation between the flow volume or presence of stenosis and fistula age. Stenosis was detected in 64% fistulas. Fifty-seven percent of stenoses were located in the anastomotic region, 22% stenoses were in vein junction, 19% were at one or both ends of aneurysm, and 2% in the remaining region of the efferent vein. Perivascular colour artefacts were present at the 94% fistulas with stenosis. Chronic venous occlusion with collateral veins was detected in 6% of fistulas. The aneurysms were observed in 54% fistulas. The mean diameter of aneurysms was 12.4 mm. Ninety-six percent of aneurysms were located at puncture sites. Ten patients had a small thrombus in an aneurysm and at puncture sites., Conclusions: We conclude that there was a high level of abnormalities present in well-functioning mature arteriovenous fistulas. However, these abnormalities were not sufficient to affect the functioning of the dialysis fistula.

Introduction: Mycobacterium tuberculosis is a facultative intracellular pathogen that developes specific T cell response expressed by the production of IL-12, IFN-gamma, and TNF-alpha. The response has been quite well investigated in the experimental models, however, there is little information about certain cytokine levels in patients with extrapulmonary tuberculosis. The shortage of data pertains also to its most common form-kidney tuberculosis, especially when bacilli dissemination into the blood circulation has occurred., Objectives: The aim of our study was to examine simultaneously the frequency of Mycobacterium tuberculosis presence in the blood circulation and the serum cytokine concentration during kidney tuberculosis to approach their relationship in the clinical infection process. It is considered that cytokine levels do not correlate with localisation of tuberculosis (pulmonary vs. extrapulmonary), however, there is little information about the cytokine levels in patients with kidney tuberculosis., Materials and Methods: 30 patients attending the urology clinic with suspicion of kidney tuberculosis were evaluated. Serum concentrations of selected cytokines in patients with urine, urine and blood Mycobacterium tuberculosis presence were quantified by ELISA and compared to PCR negative patient and group of healthy people., Results: Our study demonstrates the increase of TNF-alpha and IL-12 level in comparison to control group. TNF-alpha concentration was about 2-fold higher in the positive patients than it was in control group; IL-12 concentration was about 4-fold higher and the differences between IL-12 levels were statistically important (p < 0.05). However, no significant differences were found in IFN-gamma level among all groups. Using Spearman correlation rank test, a significant correlation was found between TNF-alpha and IL-12 in the positive patient group. The correlation factor was more significant for the group of patients with Mycobacterium tuberculosis present in blood and urine than it was in urine positive PCR group (r = -0.66 vs. r = -0.51).

Development of vascular and systemic calcification is one of the more serious and often occurring complications in hemodialyzed patients. The cardiac valves calcifications are of the essential importance. They are result of the very complicated calcification process connected with hyperphosphataemia, hyperparathyroidism, calcium carbonate administering and active vitamin D3 metabolites as well as using dialysis fluids with high concentration of calcium. Elevated P and Ca x P product are both significant predictors of cardiovascular mortality in hemodialized patients. We describe two patients with cardiac failure because of cardiac valves calcification. Both patients underwent artificial valves implantation. The patients showed a marked improvement of the quality of life and haemodynamic status.