Emission measurements with gravimetric impactors and electrical devices: An aerosol instrument comparison

Particulate matter in the atmosphere is known to affect Earth’s climate and to be harmful to human health. Accurately measuring particles from emission sources is important, as the results are used to inform policies and climate models. This study compares the results of two ELPI?+?devices, two PM10 cascade impactors and an eFilter, in combustion emission measurements. The comparison of the instruments in a realistic setting shows what types of challenges arise from measuring an emission aerosol with unknown particle morphologies and densities, different particle concentrations and high temperature. Our results show that the PM10 cascade impactors have very good intercorrelation when the collected mass is greater than 150?µg, but below that, the uncertainty of the results increases with decreasing mass. The raw signals of two ELPI?+?devices were nearly identical in most samples, as well as the particle number concentrations and size distributions calculated from raw signals; however, transforming the current distributions into mass distributions showed variation in the mass concentration of particles larger than 1?µm. The real-time time signal measured by eFilter was similar to the total current measured by ELPI+. The eFilter and PM10 cascade impactors showed similar particle mass concentrations, whereas ELPI?+?showed clearly higher ones in most cases. We concluded that the difference is at least partially due to volatile components being measured by ELPI+, but not by the mass collection measurements.

Copyright © 2019 American Association for Aerosol Research     

Indoor Planning for High Speed Downlink Packet Access in WCDMA Cellular Network

The aim of this paper is to show the special characteristics of the indoor environment related to radio propagation and furthermore to radio network planning. The aspects of the radio network planning are highlighted especially for Wideband Code Division Multiple Access (WCDMA) radio access technology that is used widely in the third generation mobile networks. Moreover, the detailed planning parameters in indoor environment are studied for High Speed Downlink Packet Access (HSDPA) in order to support high throughput data applications in Universal Mobile Telecommunications System (UMTS). The final target of the paper is to compare pico cell, distributed antenna system (DAS), and radiating cable network configurations in indoor environment to provide the optimal radio conditions for the data applications, and thus to serve highest number of mobile users. Several measurement campaigns with different antenna configurations have been conducted in order to study the effect of multi path related parameters, as delay spread of the signal. Also other capacity related parameters as received signal levels, interference, throughput, and transmit power levels have been studied in order to find out the optimal solution for HSDPA in UMTS. The results clearly show that pico cells and distributed antenna system have outstanding performance in indoor propagation channel compared to radiating cable. In sense of signal quality, pico cell performance is slightly better compared to distributed antenna system. However, measurements with HSDPA indicate that practical capacity of DAS outperforms pico cells. The measurements also show that separation of the antennas is a key capacity related parameter when planning WCDMA based indoor systems.     

High levels of equol in organic skimmed Finnish cow milk

The isoflavonoids, equol, formononetin, daidzein, genistein, biochanin A, and O-demethylangolensin (O-DMA), were analyzed from commercial cartons of skimmed Finnish milk by HPLC-diode array detector (DAD)-FL. We found 411 +/- 65 ng/mL of equol and traces of formononetin and daidzein in organic skimmed milk whereas conventionally produced milk contained 62 +/- 16 ng/mL of equol and no formononetin or daidzein.     

Dissolution properties of direcet compression tablets containing an agglomerated cellulose powder

In previous studies a novel agglomerated cellulose powder was shown to own advantageous properties for direct compression. Due to the favourable particle and powder properties this material has good binding and disintegration ability in direct compression tablets. In this study the dissolution properties of direct compression tablets containing the agglomerated cellulose powder as a fillerbinder were evaluated. Especially the effect of the amount of cellulose, the porosity of tablets, the solubility of drug material and the amount and the amount and mixing method of lubricant, magnesium stearate were studied.

Tablets containing different amounts of cellulose with dicalcium phosphate as a filler and 10 wt % of water soluble sodium tolmetin as a drug were compressed at a constant pressure of 150 MPa. The breaking strength of tablets increased with increasing amounts of agglomerated cellulose powder. However, the dissolution of drug accelerated up to cellulose amount of 50 wt %. This was due to the ability of the agglomerated cellulose powder to enhance the water penetration into powder compact and the loosening of tablet structure, i.e. formation of cracks.

Tablets containing 20 wt % of cellulose material and 10 wt % of drug material were compressed to different porosities. Tablet porosity had no effect on dissolution of poorly water soluble tolfenamic acid. Also the dissolution of water soluble sodium tolmetin was only slightly affected by the porosity of tablets. This supports the suggested disintegrant mechanism of the agglomerated cellulose powder. The expansion of cellulose agglomerates, which have been deformed, under compression, is widely responsible for the disintegration of the tablets. An increase in the amount as well as in the mixing intensity of magncsium stearate decreased the dissolution of sodium tolmetin from tablets containing 20 wt % of agglomerated cellulose. However, the intrinsic wetting and dissolution phenomens were practically unchanged when the amount of magnesium stearate was below 2 wt %. Thus, the retardation of drug dissolution was acceptable at low lubricant concentrations.

The properties of tablets containing the agglomerated cellulose were compared to those containing microcrystalline cellulose. In all cases tablets containing the agglomerated cellulose powder liberated drug clearly faster and more properly than corresponding microcrystalline cellulose tablets.     

Meta-searches in peer-to-peer networks

We propose a method for carrying out enhanced collaborative searches, called meta-searches, in peer-to-peer networks. In addition to performing regular searches, our method supports searches based on other network users’ previous searches on the same or similar topic. In essence, when a user performs a search, s/he will receive not only the usual result set, but also information on other users’ previous results, as well as relevancy information (such as how many times a resource that appeared in the result set was successfully downloaded). The core components of meta-search are query relevancy calculation, query matching algorithms, and relevancy file format. In this paper we discuss the underlying concepts and principles, and describe the component design in detail. Meta-search provides a way of benefiting from other users’ successful searches without any additional effort, thus potentially improving the efficiency and experience of a search.     

Modelling lidar-derived boreal forest canopy cover with SPOT 4 HRVIR data

Forest canopy cover (C) is needed in forest area monitoring and for many ecological models. Airborne scanning lidar sensors can produce fairly accurate C estimates even without field training data. However, optical satellite images are more cost-efficient for large area inventories. Our objective was to use airborne lidar data to obtain accurate estimates of C for a set of sample plots in a boreal forest and to generalize C for a large area using a satellite image. The normalized difference vegetation index (NDVI) and reduced simple ratio (RSR) were calculated from the satellite image and used as predictors in the regressions. RSR, which combines information from the red, near-infrared, and shortwave infrared bands, provided the best performance in terms of absolute root mean square error (RMSE) (7.3%) in the training data. NDVI produced a markedly larger RMSE (10.0%). However, in an independent validation data set, RMSE increased (13.0–17.1%) because the systematic sample of validation plots contained more variation than the training plots. Our results are better than those reported earlier, which is probably explained by more consistent C estimates derived from the lidar. Our approach provides an efficient method for creating C maps for large areas.     

Soft computing methods to predict gene regulatory networks: An integrative approach on time-series gene expression data

To unravel the controlling mechanisms of gene regulation, in this paper we present the application of sophisticated soft computing methods applied on an important problem from Bioinformatics—inferring gene regulatory networks (GRN) from time series gene expression microarray data. The main questions addressed in this paper are: (a) what knowledge can be derived from different models? (b) Would an integrated approach be more suitable to reveal about the controls of gene regulation? To reduce the number of genes in addition to apply the appropriate clustering methods, here we have also considered the valuable inputs from the biological experiments. To infer the GRN we have applied: three computational intelligence methods—Least Angle Regression (LARS), Expectation Maximization (EM) with Kalman Filter (KF), and an Evolving Fuzzy Neural Network (EFuNN). The methods are applied on time series microarray data of Schizosaccharomyces pombe yeast cell-cycle genes. Each method reveals some new aspects of the problem and it is agreed that to infer the GRN and to understand the processes behind gene regulation it is more suitable to adopt such integrative approach as ours through which some new knowledge is discovered, such as: using LARS we hypothesize—first, an exoglucanase gene exg1 is now implicated to be tied with MCB cluster regulation and second, a mannosidase with histone linked mannoses. A new quantitative prediction is that the time delay of the interaction between two genes seems to be approximately 30 min, or 0.17 cell cycles. Using the method of EM with KF, 25 cell cycle-regulated key genes were successfully clustered into three functionally co-regulated groups. We have also identified two genes namely Cdc22 and Suc22 that indeed interact with each other and are the potential candidates as a control in Ribonucleotide reductase (RNR) activity. Based on the EFuNN results and integrating knowledge from EM-KF method, we hypothesize that interaction between Suc22, Cdc22 and Mrc1 may be mediated by two other genes namely Cds1 and Spd1. The methods discussed and applied here can be used to analyze any kind of short time series of many interacting variables for inferring the regulatory network. Researchers should take such integrative computational intelligence approach seriously to understand the complex phenomenon of gene regulation and thus to simulate the development of the cell.     

Low temperature growth of SWNTs on a nickel catalyst by thermal chemical vapor deposition

Single-walled carbon nanotubes (SWNTs) have been grown on a silica-supported monometallic nickel (Ni) catalyst at temperatures ranging from as low as 450 °C to 800 °C. Different spectroscopic techniques, such as Raman, photoluminescence emission (PLE), and ultra violet-visible-near infrared (UV-vis-NIR) absorption spectroscopy were used to evaluate the diameter and quality of the SWNTs grown over the Ni catalyst at different temperatures. The analysis revealed that high quality SWNTs with a very narrow diameter distribution were obtained at a growth temperature of 500 °C. In the PLE and absorption spectra, differences were observed between the SWNTs grown on Ni and those grown on cobalt (Co). This result expands the potential of growing a specific (n, m) tube species with relatively high abundance by tuning the catalyst composition. Furthermore, the prerequisites for the low temperature growth of SWNTs over a monometallic transition metal catalyst have been elucidated.      

Endotoxins associated with cyanobacteria and their removal during drinking water treatment

The aim of this study was to investigate endotoxin concentrations in cyanobacterial water blooms and strains, and to assess the removal of endotoxins during drinking water treatment. Endotoxin concentrations were measured from 151 hepatotoxic, neurotoxic and non-toxic cyanobacterial water blooms by using Limulus amebocyte lysate (LAL) assay, and the results were compared to bacterial data. Endotoxin activities ranged from 20 to 3.8 x 10(4) endotoxin units (EU) per ml. Endotoxicity of the samples correlated with phycobiliprotein concentration that was used to assess cyanobacterial abundance, heterotrophic plate count, and Aeromonas spp. but it did not correlate with the number of coliforms or streptococci. The high endotoxin concentrations occasionally detected in the water bloom samples were probably due to Gram negative bacteria that existed together with cyanobacteria since the 26 axenic cyanobacterial strains from different genera that were studied showed very low endotoxin activity. No differences in endotoxin activity were detected between hepatotoxic, neurotoxic and non-toxic strains. Removal of endotoxins during drinking water treatment was studied at nine waterworks that previously had been associated with high numbers of cyanobacteria and that used different processes for water purification. Endotoxin concentration in raw waters ranged from 18 to 356 EU ml(-1). The treatment processes reduced 59-97% of the endotoxin activity; in the treated water the concentration ranged from 3 to 15 EU ml(-1). The most significant reduction occurred at the early stages of water treatment, during coagulation, settling and sand filtration. Activated carbon filtration either increased or had no effect on endotoxin concentration. Ozonation and chlorination had little effect on the endotoxin concentrations.