Simple Monitoring Method Research Articles

Direct quantitation of tenofovir diphosphate in human blood with mass spectrometry for adherence monitoring.

Inadequate adherence to chronic medications is a far-reaching problem with financial and human health consequences. By a wide margin, non-adherence is the leading cause of therapeutic failures of HIV pre-exposure chemoprophylaxis (PrEP) and antiretroviral therapy (ART). It has been proven that HIV infection can be prevented by daily dosing of emtricitabine and tenofovir disoproxil fumarate. Measurement of intracellular tenofovir diphosphate in red blood cells has been established as an effective way to assess cumulative adherence, however, the LC-MS-based analytical method developed for the purpose is both complicated and expensive. Here, we report a simple method for adherence monitoring based on direct MS quantification of intracellular tenofovir diphosphate in human whole blood. The method requires only microliters of whole blood, employs special membranes to perform plasma separation and concomitant desalting during blood collection, and uses nanoelectrospray on a triple quadrupole instrument. Quantitative performance in this proof-of-concept study includes RSDs of < 15% and successful analysis of a small number of patient samples with medium to high adherence levels. The results correlate with those of a validated LC-MS/MS method, and an R2 value of 0.9962 is achieved. This methodology has promise for extension to point-of-care testing using miniature mass spectrometers. Graphical abstract.

In situ and low-cost monitoring of particles falling from freshwater animals: from microplastics to parasites.

A simple and low-cost method of monitoring and collecting particulate matter detaching from (or interacting with) aquatic animals is described using a novel device based on an airlift pump principle applied to floating cages. The efficiency of the technique in particle collection is demonstrated using polyethylene microspheres interacting with a cyprinid fish (Carassius carassius) and a temporarily parasitic stage (glochidia) of an endangered freshwater mussel (Margaritifera margaritifera) dropping from experimentally infested host fish (Salmo trutta). The technique enables the monitoring of temporal dynamics of particle detachment and their continuous collection both in the laboratory and in situ, allowing the experimental animals to be kept under natural water quality regimes and reducing the need for handling and transport. The technique can improve the representativeness of current experimental methods used in the fields of environmental parasitology, animal feeding ecology and microplastic pathway studies in aquatic environments. In particular, it makes it accessible to study the physiological compatibility of glochidia and their hosts, which is an essential but understudied autecological feature in mussel conservation programs worldwide. Field placement of the technique can also aid in outreach programs with pay-offs in the increase of scientific literacy of citizens concerning neglected issues such as the importance of fish hosts for the conservation of freshwater mussels.

Development and validation of an immunochromatography test strip for rapid detection of pyrimethanil residues

ABSTRACT Pyrimethanil is one of anilinopyrimidine fungicides widely used in crop protection and frequently found in a variety of crops, including fruits, vegetables, and cereals. This paper describes the development of the first reported immunochromatography test strip (ICTS) based on colloidal gold-labeled monoclonal antibody for the detection of pyrimethanil. Under optimal conditions, the visual cut-off value of ICTS for pyrimethanil was 40 ng/mL. Using a portable strip reader, the 50% inhibition concentration and calculated LOD of pyrimethanil in the PBS samples were 4.8 and 0.9 ng/mL, respectively. When used to analyse fortified samples of fruit and vegetable, acceptable recovery rates of 83.3–105.7% with the coefficient of variation values below 11.7% were obtained. Analysis of blindly fortified samples by the proposed ICTS gave similar results to those of the ic-ELISA and HPLC-MS/MS methods. These results indicate the proposed ICTS is a rapid, simple analytical method for quantitative on-site monitoring of pyrimethanil in foodstuffs.

The uses of overnight pulse oximetry.

Overnight pulse oximetry (OPO) has proven to be an effective and beneficial technique to determine the cardiorespiratory status of patients in both the inpatient and outpatient settings. It is a cheap, safe, reliable, simple, and accurate method of patient monitoring as compared to the expensive and labor-intensive method of multichannel polysomnography for detecting sleep-disordered breathing. It provides accurate information about patient's oxygenation status and also helps in monitoring the response to continuous positive airway pressure and in the surgical treatment of obstructive sleep apnea (OSA). Nocturnal hypoxemia portends a poor prognosis in patients of chronic obstructive pulmonary disease (COPD), interstitial lung disease (ILD), and neuromuscular diseases. OPO can help its early detection and management.

Manometric real-time studies of the mechanochemical synthesis of zeolitic imidazolate frameworks.

We demonstrate a simple method for real-time monitoring of mechanochemical synthesis of metal–organic frameworks, by measuring changes in pressure of gas produced in the reaction. Using this manometric method to monitor the mechanosynthesis of the zeolitic imidazolate framework ZIF-8 from basic zinc carbonate reveals an intriguing feedback mechanism in which the initially formed ZIF-8 reacts with the CO2 byproduct to produce a complex metal carbonate phase, the structure of which is determined directly from powder X-ray diffraction data. We also show that the formation of the carbonate phase may be prevented by addition of excess ligand. The excess ligand can subsequently be removed by sublimation, and reused. This enables not only the synthesis but also the purification, as well as the activation of the MOF to be performed entirely without solvent.

Breath Acetone Sensors as Non-Invasive Health Monitoring Systems: A Review

Finding a non-invasive, painless and simple method for monitoring of health parameters and early detection of physiological disorders is of utmost importance in today’s world. Breath analysis has been attracted tremendous attention as a potentially powerful tool for studying the medical diagnosis diseases because of its noninvasive nature and capability of real-time monitoring. For metabolic monitoring, several candidates are attractive. As an example, acetone has been considered as a main breath biomarker for diabetes. In addition to diabetes, fat burn monitoring is another application for breath acetone. This article provides a comprehensive study on the state of the art research activities in gas sensor field. It mainly focuses on the metal oxide semiconductor based acetone sensors such as WO3, ZnO, SnO2, Fe2O3, In2O3, TiO2, Co2O3, NiO and etc. Several different type of acetone sensor technologies such as polymer based chemiresistors, mixed potential, optical and mass sensitive devices are presented as well. The effect of nano structures and morphology on response of sensors are discussed. The advantages and disadvantages of different techniques used for metal oxide semiconductor synthesis are also discussed. Finally, sensor arrays with different receptor materials and transducers for breath analyzing are discussed.

Monitoring Methods on Evaluating the Water-related Green Infrastructure Performance

Green Infrastructure (GI) theoretically can provide multiple ecosystem services, but its performance is uncertain and dynamic which will vary under the different environmental conditions, time and others. In different scenarios, it will probably provide optimal ecosystem service while also probably provide extremely less ecosystem service. This paper mainly focuses on exploring how to use implementable but simple monitoring methods to evaluate the performance of water-related green infrastructure, and discussing that the performance monitor is an indispensable part of GI’s design and practice. The process of “design-practice-monitor-feedback-adjustment”, effectively enhances the local GI’s design, construction, maintenance as well as the policy development level, and helps to achieve good ecological, economic and social benefits in the subsequent process.

Exploring the potential of infrared spectroscopy in qualitative and quantitative monitoring of ovalbumin amyloid fibrillation.

Amyloid fibrils are highly ordered self-assembled (poly)peptide aggregates with cross-β structural pattern. Ovalbumin was used as a model for exploring the potential of infrared spectroscopy in detecting structural transitions and quantitative monitoring of amyloid fibrillation. Low pH (pH 2) and high temperature (90 °C) over the course of 24 h were conditions applied for amyloid formation. Fibrillation of ovalbumin was monitored by ThT and ANS fluorescence, and SDS PAGE. A significant increase in ThT fluorescence with a plateau reached after 4 h of incubation, without the lag phase, was detected. Structural transitions leading to amyloid fibrillation were analysed using all three Amide regions in ATR-FTIR spectra. Significant changes were detected in Amide I and Amide III region (decrease of α-helix and increase of β-sheet peaks). To establish a fast, precise and simple method for quantitative monitoring of amyloid fibrillation, the Amide I/Amide II ratios of aggregation specific β-sheets (1625 and 1695 cm-1, respectively) with 1540 cm-1 as internal standard were used, resulting in good correlation (R2 = 0.93 and 0.95) with the data observed by monitoring ThT fluorescence. On the other hand, assessing aggregation specific β-sheet contents by self-deconvolution showed lower correlation with ThT fluorescence (R2 = 0.75 and 0.64). Here we examined structural transitions during ovalbumin fibrillation in a qualitative and quantitative manner by exploiting the full potential of Amide regions simultaneously. Secondary structure distribution was monitored using second derivative spectra in Amide I region. A novel, simple mathematical calculation for quantitative monitoring of fibrils formation was presented employing that the increase in low and high frequency aggregation specific β-sheet in Amide I region compared to the internal standard in Amide II region is suitable for fibril formation monitoring.

Determination of voriconazole in human plasma by liquid chromatography-tandem mass spectrometry and its application in therapeutic drug monitoring in Chinese patients.

ObjectiveTo develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of voriconazole in human plasma, and to evaluate its application in clinical therapeutic drug monitoring.MethodPlasma samples were obtained from Chinese patients receiving voriconazole, precipitated with methanol (using fluconazole as an internal standard), and then subjected to LC-MS/MS using an SB C18 column with a methanol and water mobile phase at a flow rate of 0.4 mL/minute. Quantification was performed by multiple-reaction monitoring using the precursor and product ion pair m/z 350–280.9 for voriconazole and m/z 307–219.9 for fluconazole.ResultsThe calibration curve was linear over a range of 0.1–10.0 µg/mL (R2 = 0.9995). The inter-day and intra-day relative standard deviations were <7.68% and <8.97%, respectively. Extraction recovery, matrix effect, and stability were also validated. Sixty-eight plasma samples from 42 patients were analyzed, and the voriconazole concentrations in 25 samples (36.8%) were outside the optimal range of 1.5–4.5 µg/mL.ConclusionsWe developed a simple and accurate method of drug monitoring, which could improve the efficacy and prevent adverse reactions of voriconazole.

A fully validated simple new method for environmental monitoring by surface sampling for cytotoxics

A wipe sampling procedure followed by a simple ultra-performance liquid chromatography – tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for simultaneous quantification of six cytotoxic drugs: 5-fluorouracil (5FU), doxorubicin (DOXO), epirubicin (EPI), ifosfamide (IF), cyclophosphamide (CP) and gemcitabine (GEM), as surrogate markers for occupational exposure.After a solid-phase extraction of wiping filter on 10 × 10 cm surface, the separation was performed within 6.5 min, using a gradient mobile phase and the analytes were detected by mass spectrometry in the multiple reaction ion monitoring mode. The method was validated according to the recommendations of the US Food and Drug Administration.The method was linear (r2 > 0.9912) between 2.5 and 200 ng per wiping sample (25 to 2000 pg/cm2) for 5FU, doxorubicin and epirubicin and between 0.2 and 40 ng per wiping sample (2 to 400 pg/cm2) for cyclophosphamide, ifosfamide and gemcitabine. The lower limits of quantification were 2.5 ng (25 pg/ cm2) for 5FU, doxorubicin and epirubicin, and 0.2 ng (2 pg/cm2) for CP, IF and GEM. Within-day and between-day imprecisions were <14.0, 10.6, 11.1, 8.7, 11.2 and 10.9% for 5-fluorouracil, doxorubicin, epirubicin, ifosfamide cyclophosphamide and gemcitabine, respectively. The inaccuracies did not exceed 2.7, 10.9, 1.1, 4.5, 1.6 and 2.9% for the studied molecules, respectively.This new sensitive validated method for surface contamination studies of cytotoxics was successfully applied on different localizations in hospital. This approach is particularly suitable to assess occupational exposure risk to cytotoxic drugs.

Research on the method of controlling the 99mTc-Technegas inhaled during 1-day pulmonary ventilation/perfusion imaging.

Our purpose was to establish a simple and feasible method for monitoring and controlling the Tc-Technegas inhaled to improve the success ratio of imaging and ensure the imaging quality. The relationship between the success ratio and the pulmonary ventilation counting rate (VCR) of 113 cases, the activity of perfusion imaging agents injected and the pulmonary perfusion counting rate (PCR) of another 114 cases were analysed retrospectively. And combined with the relationship between the surface radioactivity monitoring value and the SPECT probe counting rate of a pulmonary model, the effective range of the VCR and the surface radioactivity monitoring value were determined. Two hundred fifty cases with Tc-Technegas inhaled monitored and controlled were used to verify the reliability and practicability of this method. The VCR of the ventilation/perfusion imaging with deep venous thrombosis imaging and the ventilation/perfusion imaging without deep venous thrombosis imaging was in 1.0-3.0 kct/s and 1.0-2.0 kct/s when the monitoring values of handheld radiation monitor was within the range of 60-170 µSv/h and 60-110 µSv/h, respectively. The success ratio of the V/Q-Only increased from 48.9% (43/88) of the control group to 80.8% (122/151) of the experimental group. The VCR in the two groups was examined by the non-parametric Mann-Whitney U test (P < 0.001), which indicated that there was a significant difference between the experimental group and the control group. The external monitoring method established in this study was of great significance in improving the success ratio of 1-day pulmonary ventilation/perfusion imaging and ensuring the image quality.

A simple but quantitative method for non-destructive monitoring of myoglobin redox forms inside the meat.

This study aims at exploring a simple and quantitative method for non-destructive monitoring of the myoglobin redox forms inside of beef. The modified Beer-Lambert law was employed to derive an equation that delineates a relationship between attenuance differences and oxy-, deoxy-, and met-myoglobin proportions. An experiment with forty-three well-bled muscle beef samples during 7days of storage was performed to validate the equation. Firstly, the reflection spectra were collected from the beef samples using a probe consisting of a light source and a light detector. Secondly, the attenuance differences, A630-615 and A578-567, were calculated from the measured spectra. Finally, these attenuance differences were placed into the derived equation to determine the proportions of the three myoglobin redox forms. Both the met-myoglobin proportion and meat oxygenation computed via the attenuance differences established a strong correlation with the ones estimated using the whole spectrum (R2 > 0.88). The experimental results suggest the potential of using the attenuance at five wavelengths (524, 567, 578, 615, and 630nm) to monitor oxy-, deoxy-, and met-myoglobin inside of beef in a simple and fast manner with little to no sample preparation.

Establishment of a multiplex RT-PCR assay for identification of atmospheric virus contamination in pig farms

Spread of pathogens in pig farms not only causes transfection of diseases to other pigs or even farmers working in the farms, but also induces pollution to the living atmospheric environment of the residents around the farm. Therefore, it is necessary to establish a rapid and simple monitoring method. In this study, full genome sequences of common viruses were analyzed in pig farms, in combination with the design of primers, optimization of the reaction parameters, so as to establish a multiplex RT-PCR assay for the identification of classical swine fever virus (CSFV), Japanese encephalitis virus (JEV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine circovirus Type 2 (PCV-2), porcine pseudorabies virus (PRV) and porcine parvovirus virus (PPV), which are common in pig farms. This method has a minimal detectable concentration of 10−3 ng/μL, which is highly specific. Furthermore, multiplex RT-PCR was applied to examine air samples from 4 pig farms located in different cities of China. The results were in line with those obtained by single PCR. Therefore, this study can be expected to provide essential technique support for the early warning mechanism as well as disease prevention and control system against the major viruses.

Applying Machine Learning Algorithms for Automatic Detection of Swallowing from Sound.

Despite the severe consequences of dysfunctional swallowing, there is no simple method of monitoring swallowing outside of clinical settings. People who cannot swallow cannot eat safely, resulting in profound changes in quality of life and risk of death from aspiration pneumonia. A non-invasive swallowing detector may have widespread impact in both clinical care and research. Detection of swallowing from laryngeal sounds could become an ideal assessment tool because sounds are simple to record, quantifiable, and amenable to software analysis. The focus of this paper is to achieve high accuracy binary swallowing detection from sound recordings. A dataset with 2500 swallow sound samples and 1700 mixed laryngeal noise samples from 15 healthy adults was used to train and test three supervised machine learning algorithms. A decision tree, support vector machine (SVM), and neural network trained with the scaled conjugate gradient (SCG) method had areas under the receiver operating characteristic (ROC) curve of 0.970, 0.961, and 0.971 and average accuracies of 93.2 percent, 86.2 percent, and 93.7 percent respectively. While further work needs to be done to further optimize these algorithms and validate their efficacy, these initial results suggest machine learning strategies may be helpful to improve accuracy of swallowing detection.

Occupational risks surveillance in informal vendors from Maputo: Experience of the use of direct observation for its monitoring

Over 90% of employment in Mozambique is informal. Given scarce resources and difficulties with monitoring informal employment, little is known about exposure to occupational hazards among informal workers in this country. Direct observation is a simple, easy, economical and rapid method for monitoring and obtaining data. We describe our experience with the use of direct observation of occupational hazards among informal street vendors in Maputo. Results reveal a high percentage of vendors are exposed to occupational hazards without any form of protection. Direct observation is a good method for monitoring occupational risks in exploratory phases of research or as a complementary method to quantitative data collection.

Equivalent circuit models for a biomembrane impedance sensor and analysis of electrochemical impedance spectra based on support vector regression

In this study, an electrochemical impedance biosensor was developed as a simple and fast method for real-time monitoring of biofilm binding properties via continuous impedance spectroscopy. To prepare the sensing membrane, cells were immobilized onto gold electrodes with nitrocellulose membranes. Different cell growth features were measured with the impedance instrument and analyzed using an equivalent model for data fitting and support vector regression (SVR) for data processing. The collected impedance spectra revealed that the binding attachment areas of cells differ depending on the cell density. Our results demonstrate the usefulness and feasibility of training our impedance-based sensor with a small amount of data to predict the effective area of different biofilms (GE, NGE, and CNGE), with a prediction error of 9.8%.Graphical abstract

The study of snow pollution levels based on heavy metal concentrations in Arkhangelsk, 2017-2018

Air pollution poses a significant hazard to human health. Snow is able to accumulate pollutants present in the air. Therefore, determination of pollutants levels in the snow is a simple and effective method of environmental monitoring. Heavy metals are among the most hazardous pollutants. Various methods can be used to determine heavy metal concentrations in snow, on being total-reflection X-ray fluorescence spectroscopy (TXRF). TXRF allows for parallel identification of several dozens of metals with concentrations of the order of μg/L. Since quantitative analysis is performed using the internal standard method, calibration for each measured element is not required. An important advantage of this method is the ability to carry out measurements in a mobile laboratory. Performed in 2017 and 2018, this study aims to determine heavy metal contents in the snow in Arkhangelsk using the TXRF method. It is assumed that the contents of heavy metals do not exceed permissible levels. The relative concentrations of Fe, Mn, Ni are the most significant (with respect to MPC). The content of Cu, Zn, Sr, Pb in samples is statistically significant, while the presence of As, Cd, Hg has not be detected.

An Enhanced Evaluation Method of Sequential Probability Ratio Test

Accurate event detection has high priority in many technical applications. Events in acquired data series, their duration, and statistical parameters provide useful information about the observed system and about its current state. This information can be used for condition monitoring, state identification, and many kinds of forecasting as well. In some cases background noise covers the events and simple threshold or power monitoring methods cannot be used effectively. A novel method called Scaled Sequential Probability Ratio Test (SSPRT) produces 2D array of data via special cumulative sum calculation. A peak determination algorithm has also been developed to find significant peaks and to store the corresponding data for further evaluation. The method provides straight information about the endpoints and possible duration of the detected events as well as shows their significance level. The new method also gives representative visual information about the structure of detected events. Application example for thermomechanical fatigue test monitoring and another for vibration based rotational speed estimation of a four-cylinder internal combustion engine is discussed in this paper.

Vertical change in transparency of water at Lake Nyos, a possible indicator for the depth of chemocline

A limnic eruption in 1986 at Lake Nyos in Cameroon was caused by sudden release of magmatic CO2 dissolved in the lake water. For frequent measurements of CO2 in the lake water, we developed a simple method of CO2 monitoring using sound speed (SS) measurement. We measured the depth profile of sound speed at Lake Nyos in 2012, 2013, 2014, and 2015. Furthermore, in the 2014 and 2015 survey, we took movies of the underwater and the bottom of the lake using an underwater camera housed in a pressure-resistant container. The vertical change of transparency of water was checked by the visibility of reflectors set in front of the camera. A pressure sensor monitored the depth simultaneously. In both years, in addition to well-known red surface water, we discovered a cloudy layer near the upper chemocline around 100 m depth. The depth of chemocline is a good indicator of the change of total amount of CO2 in Lake Nyos. Because the transparency can be detected by a simple optical sensor, we can now apply our low-cost monitoring tool to find the depth of chemocline for Lake Nyos.

Continuous invasive hemodynamic monitoring using steerable guide catheter to optimize mitraclip transcatheter mitral valve repair: A multicenter, proof-of-concept study.

We report our multicenter experience on continuous hemodynamic monitoring using exclusively the steerable guide catheter (SGC) during MitraClip repair. Left atrial pressure (LAP) and V-wave are useful to evaluate MitraClip repair but no simple method of continuous monitoring exists. From 11/2016 to 8/2017, 74 patients from four centers with symptomatic moderate-severe to severe mitral regurgitation (MR), underwent MitraClip NT repair with continuous hemodynamic monitoring via the SGC. Real-time LAP/V-wave changes were compared with transesophageal echocardiography (TEE). When mitral stenosis was suspected, transmitral gradients were verified by invasive hemodynamics. Clinical and echocardiographic outcomes were determined. Mean age was 78 ± 10 years and STS score 9.1 ± 11.0%. Pathology included leaflet prolapse/flail (45%), restriction (35%), and mixed (20%). Number of clips averaged 1.7 ± 0.7 per case. There was a significant reduction in LAP (21 ± 10 to 15 ± 7 mmHg, P < 0.0001) and V-wave(37 ± 19 to 24 ± 10 mmHg, P < 0.0001) post MitraClip, but the decrease was less in patients with atrial fibrillation (P < 0.05). Transmitral gradient significantly increased from 2.0 ± 1.2 to 4.0 ± 1.7 mmHg (P < 0.0001). Paradoxical increases in LAP and V-wave despite MR reduction were observed in three cases requiring MitraClip repositioning or retrieval to avoid stenosis. Follow-up averaged 5.0 ± 2.9 months and was 100% complete. KCCQ improvement was significant and MR reduction to <1+ was 67% and <2+ was 93% at 30 days. Continuous hemodynamic monitoring using the SGC complements TEE to assess and optimize MitraClip repair in real-time. Further validation is necessary but this feature may be part of future MitraClip and other transcatheter mitral repair systems.