Off-line Mode Research Articles

The achievements of clinical chemistry testing: 1967–2017

Activated platelets and platelet derived microvesicles (PMVs) emerged recently to be promising biomarkers. There is no universal procedure to carry out the proteomic analysis on microvesicles. In this study we proposed a nano-liquid chromatography (nano-LC) technique coupled off-line with a spectrometric measurement MALDI-TOF-MS/MS as a throughput and time-saving procedure. In this study we developed a simplified method to evaluate the protein composition of platelet organelles and PMVs. Platelet-rich plasma (PRP) was collected from healthy donors. PMVs were generated from washed and thrombin activated platelets. Activated platelets from every donor were used to compare the PMV proteome. Enzymatic digestion of protein lysate was carried out using Filter Aided Sample Preparation (FASP) method with trypsin as a proteolytic enzyme. Tryptic peptides derived from PMVs and activated platelets were analysed using nano-LC coupled off-line mode with a MALDI-TOF/TOF-MS. PMV and platelet protein identification was performed using the Mascot engine for searching against the Swiss-Prot human database. The precision tolerance was 100 ppm for peptide masses and 0.7 Da for fragment ion masses. Individual peptide matches with a score above 28 were considered statistically significant. In total, 446 proteins were identified in PMVs and 513 proteins in activated platelets. Among them 190 were specific for activated platelets and 123 were PMV specific. Cellular component analysis of identified proteins revealed that PMVs contained relatively more extracellular proteins than activated platelets (9.6 vs. 6.0 %) and unique synaptic proteins (0.3%). A new simplified bottom-up method for PMV proteome analysis allowed eliminating the drawbacks of the previously used protocols. This approach can be used in PMV proteome identification.

Application of nano-LC-MALDI-TOF/TOF-MS for proteomic analysis of microvesicles

Activated platelets and platelet derived microvesicles (PMVs) emerged recently to be promising biomarkers. There is no universal procedure to carry out the proteomic analysis on microvesicles. In this study we proposed a nano-liquid chromatography (nano-LC) technique coupled off-line with a spectrometric measurement MALDI-TOF-MS/MS as a throughput and time-saving procedure. In this study we developed a simplified method to evaluate the protein composition of platelet organelles and PMVs. Platelet-rich plasma (PRP) was collected from healthy donors. PMVs were generated from washed and thrombin activated platelets. Activated platelets from every donor were used to compare the PMV proteome. Enzymatic digestion of protein lysate was carried out using Filter Aided Sample Preparation (FASP) method with trypsin as a proteolytic enzyme. Tryptic peptides derived from PMVs and activated platelets were analysed using nano-LC coupled off-line mode with a MALDI-TOF/TOF-MS. PMV and platelet protein identification was performed using the Mascot engine for searching against the Swiss-Prot human database. The precision tolerance was 100ppm for peptide masses and 0.7Da for fragment ion masses. Individual peptide matches with a score above 28 were considered statistically significant. In total, 446 proteins were identified in PMVs and 513 proteins in activated platelets. Among them 190 were specific for activated platelets and 123 were PMV specific. Cellular component analysis of identified proteins revealed that PMVs contained relatively more extracellular proteins than activated platelets (9.6 vs. 6.0 %) and unique synaptic proteins (0.3%). A new simplified bottom-up method for PMV proteome analysis allowed eliminating the drawbacks of the previously used protocols. This approach can be used in PMV proteome identification.

Ligand Fishing: A Remarkable Strategy for Discovering Bioactive Compounds from Complex Mixture of Natural Products.

Identification of active compounds from natural products is a critical and challenging task in drug discovery pipelines. Besides commonly used bio-guided screening approaches, affinity selection strategy coupled with liquid chromatography or mass spectrometry, known as ligand fishing, has been gaining increasing interest from researchers. In this review, we summarized this emerging strategy and categorized those methods as off-line or on-line mode according to their features. The separation principles of ligand fishing were introduced based on distinct analytical techniques, including biochromatography, capillary electrophoresis, ultrafiltration, equilibrium dialysis, microdialysis, and magnetic beads. The applications of ligand fishing approaches in the discovery of lead compounds were reviewed. Most of ligand fishing methods display specificity, high efficiency, and require less sample pretreatment, which makes them especially suitable for screening active compounds from complex mixtures of natural products. We also summarized the applications of ligand fishing in the modernization of Traditional Chinese Medicine (TCM), and propose some perspectives of this remarkable technique.

Determination of antipsychotic drugs in hospital and wastewater treatment plant samples by gas chromatography/tandem mass spectrometry.

The development and performance evaluation of a method for the simultaneous determination of six antipsychotic drugs in hospital effluents and wastewater treatment plants (WWTP) samples are herein presented. The method involves an off-line mixed mode (reversed-phase and strong cation exchange) solid phase extraction (SPE) with gas chromatography (GC) coupled to tandem mass spectrometry (MS/MS). The present methodology was validated following internationally accepted criteria, and the studied parameters included selectivity, linearity, limits of detection (LOD) and quantitation (LLOQ), instrumental limits, precision and accuracy, stability and recovery. The procedure was linear for concentrations ranging from 0.1 to 10μg/L (0.02 to 2μg/L for haloperidol), with determination coefficients higher than 0.99 for all analytes. Intra- and inter-day precision was lower than 15% for all analytes at the studied concentrations, while accuracy remained between a ±15% interval. Recoveries ranged from 31% to 83%. Low LODs were achieved, between 2 and 10ng/L, allowing a reliable identification of all analytes at trace levels, using only 50mL as sample volume. All studied parameters complied with the defined criteria and the method was successfully applied to gather preliminary results of the determination of antipsychotics on hospital effluents and on influent and effluent of WWTPs, opening perspectives for the study of their fate in the aquatic environment.

Development of a capacitance sensing system for monitoring moisture content of spray dried gelatin powders

For on-line, non-contact measurement of moisture content (MC) of spray dried products, a capacitance sensing system was developed using pairs of copper plates attached to the perimeter of the spray dryer measuring cylinder. The plates formed capacitors which were sensitive to changes in dielectric properties, which in turn were related to MC. The self-built system was tested on spray dried gelatin powders in three modes: a) an off-line mode to test the capabilities of the sensor at different MC levels (4%–44% (d.b.)); and b) an on-line mode to measure MC of samples passing through the sensor enclosure. Results indicated this system was feasible to measure MC both statically and dynamically, but it had better performance for off-line samples (R2 = 0.98, RMSE = 1.9%); c) this system was also used in an ECT mode and showed the capability to reflect spatial distribution of deposition during spray drying.

An Experimental Approach and Monitoring Tools for Evaluating a Dynamic Cubing System

In this paper, the authors propose an approach and different tools to evaluate the performance and assess the effectiveness of a model in the field of dynamic cubing. Experimental evaluation, on one hand allows observing the behavior and the performance of the solution, while on the other hand it lets one compare the results with those of the other competing solutions. The authors' proposal includes an experimental workflow based on a set of configuration parameters to characterize the inputs (data sets, queries sets and algorithm input parameters) and a set of metrics to analyze and qualify the output (performance and behavior metrics) of the solution. They have identified a number of useful tools necessary to develop an experimental evaluation strategy. These monitoring tools allow elaborating the execution scenarios, collecting output metrics and storing and analyzing them online in real-time as well as later in off-line mode. Using a use-case model, the authors show that the framework and the proposed environment help carrying out a rigorous experimental evaluation of a dynamic cubing solution.

RADON-222 DETECTION USING BETA-DECAY PRODUCTS

The paper shows the possibility of determining of the radon by the radiometer on a base of multi-channel time analyzer of beta – decay products of radon. The radiometer consist of an electrostatic aerosol collector combined with the air intake, Geiger-Muller counter for detection of beta particles and multi-channel time analyzer. Accumulation time of aerosol sample takes up to 20 min, the time data processing is done by the radiometer about 5 hours. The data processing is at off-line mode using the computer decomposition process of decay spectrum.

Determination of adduct forms of antitumor ruthenium(III) complex with cytosolic components by capillary electrophoresis with mass spectrometry

Using capillary electrophoresis with inductively coupled plasma mass spectrometry, the transformation of adduct forms of indazolium trans-[tetrachloridobis(1H-indazole)ruthenate(III)] with apo-transferrin and albumin under the effect of active intracellular reducing agents, glutathione and ascorbic acid, and citric acid as a complexant was studied under conditions simulating a cytosolic environment. These adducts of ruthenium with transport proteins are forms in which the anticancer drug exists after intravenous administration. Two modes of interaction of adducts with glutathione, ascorbic acid, and citric acid were studied: in a capillary using a background electrolyte containing a cytosolic active ingredient and upon incubation of the reaction components in the off-line mode, followed by their separation and determination by capillary electrophoresis. Incubation with intracellular components and separation were carried out in a 10 mM phosphate buffer solution (pH 6.0) containing 4 mM NaCl. The effect 1–10 mM of glutathione, 10 mM of ascorbic acid, and 50 mM of citric acid on the adducts was studied. It is shown that under the selected model conditions, new forms of ruthenium do not emerge.

Realistic Projection on Casual Dual-Planar Surfaces with Global Illumination Compensation

Projectors are deployed in increasingly demanding environments. The fidelity of the projected image as seen by a user is compromised when projectors are deployed in dual-planar environments (e.g. corner of a room or an office cubicle), thereby diminishing the richness of the user experience. There are many reasons for this. The focus of this paper is to compensate for the global illumination effects due to inter-reflection of light. In the process we also correct geometry distortion. Our system is built from off-the-shelf components and easily deployable without any elaborated setup. In this paper, we describe two complementary methods to compensate for global illumination effects in dual-planar environments. Our methods are based on the systematic adaptation and interpretation of the classical radiosity equation in the image domain. The technique neither assumes nor computes 3D scene geometry, relying on an implicit inference. The system is calibrated in an off-line mode once; in our first method, corrected images and video are computed in real time, and in our second method, a richer scene is offered with a modest increase in computational time. The corrected images when projected have better contrast and are more appealing to the user.

MSFIA-LOV system for 226Ra isolation and pre-concentration from water samples previous radiometric detection

An automatic system based on multisyringe flow injection analysis (MSFIA) and lab-on-valve (LOV) flow techniques for separation and pre-concentration of 226Ra from drinking and natural water samples has been developed. The analytical protocol combines two different procedures: the Ra adsorption on MnO2 and the BaSO4 co-precipitation, achieving more selectivity especially in water samples with low radium levels.Radium is adsorbed on MnO2 deposited on macroporous of bead cellulose. Then, it is eluted with hydroxylamine to transform insoluble MnO2 to soluble Mn(II) thus freeing Ra, which is then coprecipitated with BaSO4. The 226Ra can be directly detected in off-line mode using a low background proportional counter (LBPC) or through a liquid scintillation counter (LSC), after performing an on-line coprecipitate dissolution. Thus, the versatility of the proposed system allows the selection of the radiometric detection technique depending on the detector availability or the required response efficiency (sample number vs. response time and limit of detection).The MSFIA-LOV system improves the precision (1.7% RSD), and the extraction frequency (up to 3 h−1). Besides, it has been satisfactorily applied to different types of water matrices (tap, mineral, well and sea water). The 226Ra minimum detectable activities (LSC: 0.004 Bq L−1; LBPC: 0.02 Bq L−1) attained by this system allow to reach the guidance values proposed by the relevant international agencies e.g. WHO, EPA and EC.

New functionalised polymeric microspheres for multicomponent solid phase extraction of phenolic compounds

Three new porous copolymers possessing basic character were prepared by chemical modification of polymeric adsorbent (copolymer of bis[4(2-hydroxy-3-methacryloyloxypropoxy)phenyl]sulfide and glycidyl methacrylate, BES.DM + GMA). Modification was carried out by reactions of surface epoxide groups of the precursor with amines: butylenediamine, diethylenetriamine and triethylenetetramine. Next, two of the synthesized materials were chosen for further modification involving addition of HCO3 − groups to amine species. The obtained polymer adsorbents were characterised by elemental analyses, FTIR, nitrogen adsorption and thermal analyses. The prepared copolymers were studied for use as adsorbent in solid phase extraction (SPE) of multicomponent mixture of phenolic compounds consisting of: phenol, 2-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol. The SPE experiments were carried out in off-line mode. The influence of the chemical modification on adsorption properties of the presented materials was observed. The prepared adsorbents possessed different sorption properties towards the phenols. In addition, a competition phenomenon of the testing compounds for active sites on the polymer surface was observed. The most effective in adsorption of phenol and its chlorinated derivatives were the polymers with both amine and bicarbonate groups. The best recovery results were obtained for 2,4-dichlorophenol.

Selective determination of COXIBs in environmental water samples by mixed-mode solid phase extraction and liquid chromatography quadrupole time-of-flight mass spectrometry

The development and performance evaluation of a method for the simultaneous determination of six pharmaceuticals belonging to the class of non-steroidal anti-inflammatory drugs (NSAIDs) which present high selectivity for the cyclooxygenase (COX)-2 isoform of COX (COXIBs) in environmental waters are presented. The method involves an off-line mixed mode (reversed-phase and strong anionic exchange) solid phase extraction (SPE) for the selective concentration of COXIBs in combination with liquid chromatography (LC) quadrupole time-of-flight (QTOF) mass spectrometry (MS). The use of a strong anionic exchange sorbent (Oasis MAX) led to a significant reduction of matrix effects, during electrospray ionization (ESI), in comparison with results obtained for mixed mode weak anionic exchange sorbent (Oasis Wax) and polymeric reversed phase sorbents (Oasis HLB and Strata X).The developed method attained limits of quantification (LOQs) between 0.01 and 0.20ngL−1 for river water and effluent wastewater and, for influent wastewater this limits were ranged between 0.03 and 0.45ngL−1.Among the pharmaceuticals investigated, two of them (celecoxib and etoricoxib) were detected at low levels (ppt) in real samples of treated and raw wastewaters, and two metabolites were also found; the carboxylated celecoxib and the hydroxylated etoricoxib.

BOOK@HAND BIDL: Mobile Exploring of the Bulgarian Iconography by Using Panorama Pictures

The paper presents the newest developments in integrating Bulgarian Iconographical Digital Library (BIDL) and the tourist mobile application family named as (GUIDE@HAND). The integration made it possible for collections to be created by the user at the BIDL Web page and then downloaded to the GUIDE@HAND Veliko Tarnovo application by using QR codes. This year, a new standalone offline mobile application (BOOK@HAND) was created providing information on icons available in BIDL where the collection presentation functionality of the former system was enhanced with new features. The main novelty of the application is the option to present collections in a virtual exhibition room by using panorama pictures in off-line mode.

Experience of using FEM for real-time flood early warning systems: Monitoring and modeling Boston levee instability

Boston levee has a documented history of slope slippages under tidal fluctuations reaching 6-m range on spring tides. A finite element model of the Boston levee has been developed in the off-line mode; after that, it was integrated into the common information space of the UrbanFlood early warning system and connected to live sensor data stream registering tidal fluctuations of river level and corresponding response of pore pressures and media temperatures. Stability analysis was carried in a real-time mode.Besides finite element method, limit equilibrium analysis of levee stability was used in parallel. Real-time assessment of stability was performed by interpolating between safety factors pre-computed for a number of different tidal phases. FEM results indicate instability and agree with real-life observations, while LEM predicted safe condition of the dike. The mismatching is caused by a simplified procedure of pore pressures calculation which is typically used in LEM. For clayey levees, this simplification can lead to over-estimation of slope stability.The Boston levee case has become one of the pilot sites for validation of the UrbanFlood early warning system (EWS) for flood protection. This validation case has shown that the FEM module for levee stability analysis successfully operates in the real-time workflow of the EWS and correctly predicts levee instability.

Development of a novel graphene/polyaniline electrodeposited coating for on-line in-tube solid phase microextraction of aldehydes in human exhaled breath condensate

In this work, we introduced a novel graphene/polyaniline (G/PANI) electrodeposited coating for on-line in-tube solid phase microextraction (IT-SPME) for the first time. The G/PANI coating was prepared on the internal surface of stainless steel tube by a facile in-situ electrodeposition method. The morphology and formation of the composite coating were confirmed by scanning electronic microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Some important experimental parameters that could affect the extraction and separation such as the coating thickness, internal diameter of tube, sampling flow rate as well as sample volume were optimized. The extraction performance of the IT-SPME coating was evaluated systematically. The coating exhibited enhanced mechanical stability, long lifespan, large specific surface area and good biocompatibility compared with polyaniline coating. The on-line IT-SPME method showed higher enrichment efficiency, faster analysis speed and higher automation level than off-line manual mode. Six aldehydes were determined simultaneously with low limits of detection of 0.02–0.04nmolL−1 and good linearity (R2≥0.9920). The method has been applied successfully for the determination of aldehydes in human exhaled breath condensates with good recovery (70–120%) and satisfied reproducibility (relative standard deviation: 1.1–11.9%). This on-line IT-SPME method provides a promising approach for the determination of trace aldehydes with approving sensitivity in human exhaled breath condensates.

Rapid screening of phytoremediation effluents by off-line tetramethylammonium hydroxide assisted thermochemolysis

Tetramethylammonium hydroxide-assisted thermochemolysis performed in an off-line mode proved a useful tool in determining organic compounds in the effluent from laboratory-scale phytoremediation systems. Studies were performed with artificial wastewaters contaminated with xylenols and densely rooted Juncus effuses plants. Analytes in these molecular-level based studies included xylenol substrates, an array of stable intermediates such as low molecular weight carboxylic acids and oxidative coupling products (tetramethyl biphenyldiols, tetramethyl diphenylether monools), diagnostic fatty acid biomarkers, as well as lignin-, carbohydrate-, and protein-based phenols and carboxylic acids. Lignin-based breakdown products belonged to p-hydroxyphenyl- and guaiacyl-units, with lower abundance of syringyl units and the dominance of acids over phenols. Monomeric lignin-, protein- and carbohydrate-based breakdown products could not be detected in the non-treated lyophilized effluent. The formation of diketopiperazines pointed to soluble peptides and proteins. The procedure described herein can easily be applied in every modern laboratory to characterize underlying processes in phytoremediation.

A buffer-aware HTTP live streaming approach for SDN-enabled 5G wireless networks

With increasing interest in the concept of 5G wireless networks and the popularization of mobile devices, users gradually watch videos through mobile devices in streaming mode rather than off-line mode. However, the latency and lags of mobile networks will reduce the quality of service. In HTTP live streaming services, when there are multiple sources for the same content stored in the streaming servers, the suited quality content is able to be selected for playing according to the networking bandwidth conditions between servers and user equipment, and the users can obtain appropriate streaming quality automatically. However, the selection policy is difficult to be approved between 5G wireless communication networks and SDNs. In this study a buffer-aware HTTP live streaming approach is proposed, which evaluates the weights of media segments to decide the transmitting priorities based on the current playing time and adjust the appropriate transmission path through the decision making network controller according to the utilization and stability of the routers and switches in SDN. Finally, the experimental results proved that the approach is able to correct the overall streaming source sequence with the buffer status to effectively upgrade overall streaming service quality, as well as maintain a certain level of streaming quality for SDN-enable 5G wireless networks.

Innovative approach in signal processing of electromyography signals

with its potential implementation for the purpose of HMI systems, where embedded platforms are applied. The method does not involve any traditional, statistical signal processing methods. Materials and methods. The proposed method differs from the traditional signal processing methods due to the no need of using equipment with high-computing power, which results with its wide potential implementation. Signal processing of various bio-signals is currently a very dynamically developing scientific area. The innovation of the proposed solution relies on its simplicity, efficiency and waht’s more – it does not implement any statistical signal processing. Results. The proposed method has prospective implementation for the control purpose in order to improve quality of life for handicapped users. Conducted research was intended for potential application on an embedded system platform, which has caused some significant limits in choosing an appropriate signal processing method. Traditional, sophisticated, statistical signal processing methods were not used for the purpose of this work. Discussion. This paper is a pilot study for the prospective EMG-based control of an artificial hand. The conducted analysis was done in an off-line mode, however further plans on on-line signal processing plans were made. All calculations were done in MATLAB. Conclusions. The paper presents an innovation as no other similar methods were found in literature. The paper also shows

Security Analysis and Improvement on Two RFID Authentication Protocols

Several lightweight RFID authentication protocols have been proposed to settle the security and privacy problems. Nevertheless, most of these protocols are analyzed and they are not successful in their attempt to achieve the claimed security objectives. In this paper, we consider the security of two recently proposed typical RFID authentication protocols: RAPLT protocol and SRP+ protocol. RAPLT protocol is a new ultra-lightweight RFID protocol based on two new operations named $$merge$$merge and $$separation$$separation. Utilizing the linear property of the $$merge$$merge operation, we present a passive disclosure attack on RAPLT protocol, and we can deduce the shared secrets with overwhelming probability after eavesdropping about 100 round authentication sessions. SRP+ protocol is a novel secure RFID authentication protocol conforming to the EPC C-1 G-2 standard, and we present efficient de-synchronization attack and passive disclosure attack through exhaustive search. Our disclosure attack only needs one run of the protocol, and the attack complexity is $$O(2^{16})$$O(216) evaluation of the PRNG function in off-line analysis mode. In addition, to counteract the vulnerabilities, we propose a new modified version of SRP+ protocol, denoted by $$ SRP ^{++}$$SRP++, conforming to the EPC C-1 G-2 standard. Our security analysis demonstrates that $$ SRP ^{++}$$SRP++ protocol can resist the exhaustive search attack with the complexity $$O(2^{32})$$O(232), which is the optimal security bound.

From daily climatic scenarios to hourly atmospheric forcing fields to force Soil-Vegetation-Atmosphere transfer models

This paper presents a method to produce long term climatic forcing fields to force Soil-Vegetation-Atmosphere transfer (SVAT) models in off-line mode. The objective is to increase the temporal frequency of existent climate projections databases from daily frequency to hourly time step to be used in impact climate studies. A statistical clustering k-means method is used. A tens of clusters seems to be enough to describe the climate variability in term of wind regimes, precipitation and thermal and humidity amplitude. These clusters are identified in the future projections of climate and reconstructed sequences at hourly frequency are obtained for all the forcing variables needed by a SVAT model, typically: air temperature, specific humidity, wind speed and direction, precipitation, direct short-wave radiation, downward long-wave radiation, and scattered short-wave radiation. Eleven years of observations from two sites in France are used to illustrate the method: the Chartres station (Paris) and Blagnac station (Toulouse). The reconstruction algorithm is able to produce diurnal cycles that fits well with hourly series from observations (1998–2008; 1961–1990) and from climatic scenarios (1961–2100). The diurnal amplitude and mean value is well represented for variables with marked daily cycle as temperature or humidity. Changes in the mean wind direction are represented and, to a certain extent, changes in wind intensity are also retained. The mean precipitation is conserved during the day even if the method is not able to reproduce the short rain picks variability. Precipitation is used as input in the clusterization process so in clusters representative of rainy days some diurnal variability is nevertheless retained.