Online monitoring system for qualitative and quantitative analysis of bioaerosols by combined ATP bioluminescence assay with loop-mediated isothermal amplification.

Rapid detection of airborne pathogens is crucial in preventing respiratory infections and allergies. However, technologies aiming to real-time analysis of microorganisms in air remain limited due to the sparse and complex nature of bioaerosols. Here, we introduced an online bioaerosol monitoring system (OBMS) comprised of integrated units including a rotatable stainless-steel sintered filter-based sampler, a lysis unit for extracting adenosine triphosphate (ATP), and a single photon detector-based fluorescence unit. Through optimization of the ATP bioluminescence method and establishment of standard curves between relative luminescence units (RLUs) and ATP as well as microbial concentration, we achieved simultaneous detection of bioaerosols' concentration and activity. Testing OBMS with four bacterial and two fungal aerosols at a sampling flow rate of 10 to 50 L/min revealed an outstanding collection efficiency of 95 % at 30 L/min. A single OBMS measurement takes only 8 min (sampling: 5 min; lysis and detection: 3 min) with detection limits of 3 Pcs/ms photons (2.9 × 103 and 292 CFU/m3 for Staphylococcus aureus and Candida albicans aerosol). In both laboratory and field tests, OBMS detected higher concentrations of bioaerosol compared to the traditional Andersen impactor and liquid biosampler. When combined OBMS with loop-mediated isothermal amplification (LAMP), the bioaerosol can be qualitative and quantitative analyzed within 40 min without the cumbersome procedures of sample pretreatment and DNA extraction. These results offer a high compressive and humidity resistance membrane filtration sampler and validate the potential of OBMS for online measurement of bioaerosol concentration and composition.

Development of a real-time and multitasking system for long-term monitoring of aqueous metallic elements using plasma spectroscopy.

In this work, we integrated a Raspberry Pi (RPi) board, an open-sourced hardware, with a spectrometer, a high voltage DC power source, and a plasma system to develop a multi-tasking monitoring system for metallic elements in solution. In this system, RPi precisely controls voltage pulses, synchronizes them with the spectrometer, and performs real-time analysis using data acquired in real-time. This integration enables continuous monitoring of multiple metallic elements in solutions of varying conductivities. Synchronization of voltage pulses and spectrometer triggering is crucial for reliable measurements and prolongs the lifetime of the electrode. This multitasking capability significantly improves the quality of the overall spectroscopic data and enables operation in a long-term manner. Two operating modes are proposed, namely regular detection mode (RDM) and event-based mode (EBM). RDM is used to identify the existence of metallic elements and EBM is used for quantification upon detection. A 24-h long-term test shown in this work demonstrates the system capability in of utilizing RDM to monitor the presence of Pb and Mg every 30 min. Injection of Pb- and/or Mg-containing solutions is performed to activate EBM for quantification analysis. Instant warning messages can be sent upon metal detection showcasing the system potential for real-time monitoring and efficient quantification. We believe this work can contribute to multiple fields such as environmental monitoring, industrial quality control, or process monitoring.

Avoidance behaviour of aquatic macroinvertebrates for real-time detection of micropollutant surge in wastewater effluents.

Micropollutants are regularly detected at the outlets of wastewater treatment plants (WWTPs). Across urban and industrial WWTPs, monitoring directives only require assessment for a handful of chemicals via sampling methods that fail to capture the temporal variability in micropollutant discharge. In this study, we develop a biotest for real-time on-line monitoring of micropollutant discharge dynamics in WWTPs effluents. The selected biomonitoring device ToxMate uses videotracking of invertebrate movement, which was used to deduce avoidance behaviour of the amphipod Gammarus fossarum. Organism conditioning was set up to induce a state of minimal locomotor activity in basal conditions to maximise avoidance signal sensitivity to micropollutant spikes. We showed that with a standardised protocol, it was possible to minimise both overall movement and sensitivity to physio-chemical variations typical to WWTP effluents, as well as capture the spikes of two micropollutants upon exposure (copper and methomyl). Spikes in avoidance behaviour were consistently seen for the two chemicals, as well as a strong correlation between avoidance intensity and spiked concentration. A two-year effluent monitoring case study also illustrates how this biomonitoring method is suitable for real-time on-site monitoring, and shows a promising non-targeted approach for characterising complex micropollutant discharge variability at WWTP effluents, which today remains poorly understood.

Review on recent progress in on-line monitoring technology for atmospheric pollution source emissions in China.

Emissions from mobile sources and stationary sources contribute to atmospheric pollution in China, and its components, which include ultrafine particles (UFPs), volatile organic compounds (VOCs), and other reactive gases, such as NH3 and NOx, are the most harmful to human health. China has released various regulations and standards to address pollution from mobile and stationary sources. Thus, it is urgent to develop online monitoring technology for atmospheric pollution source emissions. This study provides an overview of the main progress in mobile and stationary source monitoring technology in China and describes the comprehensive application of some typical instruments in vital areas in recent years. These instruments have been applied to monitor emissions from motor vehicles, ships, airports, the chemical industry, and electric power generation. Not only has the level of atmospheric environment monitoring technology and equipment been improving, but relevant regulations and standards have also been constantly updated. Meanwhile, the developed instruments can provide scientific assistance for the successful implementation of regulations. According to the potential problem areas in atmospheric pollution in China, some research hotspots and future trends of atmospheric online monitoring technology are summarized. Furthermore, more advanced atmospheric online monitoring technology will contribute to a comprehensive understanding of atmospheric pollution and improve environmental monitoring capacity.

Liquid Core Detection and Strand Condition Monitoring in a Continuous Caster Using Optical Fiber.

Real-time monitoring of the liquid core position during the continuous casting of steel has been demonstrated using low-cost distributed optical-fiber-based strain sensors. These sensors were installed on the containment roll support structures in the segments of a production continuous caster to detect the position of the solid-liquid interface and monitor the strand condition during the continuous casting. Distributed Fiber Bragg Grating sensors (FBGs) were used in this work to monitor strain at six roll positions in the caster. The sensor performance was first validated by comparing optical strain measurements with conventional strain gauge measurements in the lab. Next, optical strain measurements were performed on an isolated caster segment in a segment maintenance facility using hydraulic jacks to simulate the presence of a liquid core under the roll. Finally, the sensors were evaluated during caster operation. The sensors successfully detected the load increase associated with the presence of a liquid core under each instrumented roll location. Incidents of bulging and roll eccentricity were also detected using frequency analysis of the optical strain signal. The liquid core position measurements were compared using predictions from computer models (digital twins) in use at the production site. The measurements were in good agreement with the model predictions, with a few exceptions. Under certain transient caster operating conditions, such as spraying practice changes and SEN exchanges, the model predictions deviated slightly from the liquid core position determined from strain measurements.

[Monitoring of atmospheric CH4, CO, CO2, N2O and SF6 using three-channel gas chromatography].

China is approaching a critical period of carbon peak and carbon neutrality. To assess the impact of carbon peak and carbon neutrality measures, an accurate understanding of the variations of the spatial and temporal distribution of greenhouse gases is crucial. Gas chromatography, a classical approach for greenhouse gas observation, can be employed for the high-precision analysis of partial greenhouse gases. In this research, a new greenhouse gas analytical system capable of measuring five gases (CH4, CO, CO2, N2O and SF6) on a single instrument was developed based on the traditional gas chromatography approach. The following are the chromatographic operation conditions. The carrier gases were high purity N2(99.999%) and argon-methane (5% methane in argon, 99.9999%), and a stainless steel switching valve triggered the injection. Compressed CH4, CO, CO2, N2O and SF6 mixed standard gases were stored in a 0.029 m3 aluminum alloy steel cylinder for this experiment. After numerous rounds of calibration by Greenhouse Gas Laboratory of Atmospheric Sounding Center of China Meteorological Administration, the gas scale met the primary standard of World Meteorological Organization (WMO). The main performance of the system, including the measurement precision, accuracy and linear response, was tested. The results showed that the detection performance of the system met the quality standards of WMO/Global Atmospheric Watch (GAW). Precision test results indicated that the relative standard deviations (RSDs) of the mole fractions of CH4, CO, CO2, N2O and SF6 were 0.08%, 1.90%, 0.05%, 0.08%, and 0.66%, respectively. For the linear and accuracy test, the C1-C5 tested standard gases were employed and the deviations of five gases (CH4, CO, CO2, N2O and SF6) between the calculated mole fractions of the regression equation and calibrated mole fractions were 0.15×10-9, 0.20×10-9, 0.37×10-6, 0.35×10-9 and 0.02×10-12, respectively. For CH4, CO, CO2, N2O and SF6, the linear regression coefficients (R2) between the peak areas or heights and calibrated mole fractions were 0.9999. The linear regression residual and accuracy could roughly meet the expanded target of WMO/GAW quality control. The atmospheric greenhouse gases in the Hangzhou urban area were continuously measured from May 2021 to July 2021 using the developed system. The results revealed that atmospheric CH4, CO, CO2 and N2O have visible diurnal variation characteristics that were primarily affected by anthropogenic emissions. The target standard gases were measured every 2 h to monitor the stability of the system operation, and the gas mole fractions of the system response were routinely computed and compared with the assigned calibrated values. The results demonstrated that the system had good stability during the observation period and could meet the requirements of high-precision monitoring. The comprehensive test and trial operation results showed that the developed system had good precision, accuracy, linearity and stability.

On-line monitoring of the dopamine-based molecular imprinting processes for protein templates with the assistance of a fluorescent indicator.

On-line monitoring of the dopamine (DA)-based molecular imprinting processes over Fe3O4@SiO2-NH2 nanoparticles (SiMNPs) is reported by using a real-time quantitative PCR machine. Taking advantages of the efficient fluorescence quenching capability of polydopamine (PDA) and its high binding affinity to rhodamine B (RhB), we performed molecular imprinting against different proteins with free dopamine as the functional monomer and RhB as a fluorescent indicator. Along with the template molecules, the fluorescent indicators were continuously encapsulated into the PDA layer formed on the surface of the SiMNPs, resulting in immediate quenching of the fluorescence, which can be conveniently monitored in real time. As proteins showed sequence-dependent influences on the oxidation of dopamine and subsequent self-assembly on the surface of the SiMNPs, the observed fluorescence signals clearly indicated the polymerization progress in the presence of the template proteins, allowing precise control of the reaction time for different templates at a given initial concentration. The optimum end point of the reaction was found to be when 90 ± 3% of the templates had been encapsulated into the polymer, which offered the highest imprinting factor and selectivity. We applied the approach to prepare a primary PDA-based surface imprinted polymer for a multifunctional protein apurinic/apyrimidinic endonuclease/redox effector factor 1 (APE1). After further introduction of 3-hydroxyphenylboronic acid to the interfaces between APE1 and PDA, the resultant molecularly imprinted polymers (MIP-II) enabled quantitative isolation APE1 from cell lysate samples. The developed approach will be useful for the quantitative preparation of PDA-based MIPs for precious template proteins with limited input quantity. It is also applicable for further study on the effects of different proteins or peptides on the PDA formation reactions.

On-Line Optical Monitoring of the Mixing Performance in Co-Rotating Twin-Screw Extruders.

The use of real-time techniques to evaluate the global mixing performance of co-rotating twin-screw extruders is well consolidated, but much less is reported on the specific contribution of individual screw zones. This work uses on-line flow turbidity and birefringence to ascertain the mixing performance of kneading blocks with different geometries. For this purpose, one of the barrel segments of the extruder was modified in order to incorporate four sampling devices and slit dies containing optical windows were attached to them. The experiments consisted in reaching steady extrusion and then adding a small amount of tracer. Upon opening each sampling device, material was laterally detoured from the local screw channel, and its turbidity and birefringence were measured by the optical detector. Residence time distribution curves (RTD) were obtained at various axial positions along three different kneading blocks and under a range of screw speeds. It is hypothesized that K, a parameter related to the area under each RTD curve, is a good indicator of dispersive mixing, whereas variance can be used to assess distributive mixing. The experimental data confirmed that these mixing indices are sensitive to changes in processing conditions, and that they translate the expected behavior of each kneading block geometry.

Microfluidic Oxidation of Graphite in Two Minutes with Capability of Real-Time Monitoring.

Graphite oxide and its exfoliated counterpart, graphene oxide, are important precursors for the large-scale production of graphene-based materials and many relevant applications. The current batch-style preparation of graphite oxide suffers from safety concern, long reaction time, and nonuniform product quality, due to the large volume of reactors and slow energy exchange. Reaction in microchannels can largely enhance the oxidization efficiency of graphite due to the enhanced mass transfer and extremely quick energy exchange, by which the controllable oxidization of graphite is achieved in ≈2 min. Comprehensive characterizations show that the graphene oxide obtained through the microfluidic strategy has features like those prepared in laboratory beakers and industrial reactors, yet with the higher oxidization degree and more epoxy groups. More importantly, the microfluidic preparation allows for on-line monitoring of the oxidization by Raman spectroscopy, ready for the dynamical control of reaction condition and product quality. The capability of continuous preparation is also demonstrated by showing the assembly of fibers and reduction of graphene oxide in microfluidic channels, and the applicability of graphene oxide prepared from the microfluidic strategy for thermally and electrically conductive films.

Measuring Nd(III) Solution Concentration in the Presence of Interfering Er(III) and Cu(II) Ions: A Partial Least Squares Analysis of Ultraviolet-Visible Spectra.

Optical spectroscopy is a powerful characterization tool with applications ranging from fundamental studies to real-time process monitoring. However, it can be difficult to apply to complex samples that contain interfering analytes which are common in processing streams. Multivariate (chemometric) analysis has been examined for providing selectivity and accuracy to the analysis of optical spectra and expanding its potential applications. Here we will discuss chemometric modeling with an in-depth comparison to more simplistic analysis approaches and outline how chemometric modeling works while exploring the limits on modeling accuracy. Understanding the limitations of the chemometric model can provide better analytical assessment regarding the accuracy and precision of the analytical result. This will be explored in the context of UV-Vis absorbance of neodymium (Nd3+) in the presence of interferents, erbium (Er3+) and copper (Cu2+) under conditions simulating the liquid-liquid extraction approach used to recycle plutonium (Pu) and uranium (U) in used nuclear fuel worldwide. The selected chemometric model, partial least squares regression, accurately quantifies Nd3+ with a low percentage error in the presence of interfering analytes and even under conditions that the training set does not describe.

Environmental impact, treatment technology and monitoring system of ship domestic sewage: A review.

Marine pollution caused by the substandard discharge of domestic sewage from ships has received considerable attention in recent years. Thus, the research and application of efficient treatment and supervision system of domestic ship sewage are matters of considerable interest in marine pollution prevention. The environmental impacts of black and grey water on marine and river environments were reviewed to emphasize the urgency and importance of sewage treatment. Development and changes of emission indexes revealed the emphasis on marine environmental protection and domestic sewage discharge. Based on summarizing the difficulties of high salinity, high organic load and poor stability in ship sewage treatment, the technologies of physical-, chemical- and biochemical-based processing were reviewed. Case study of online monitoring system was displayed to provide research trends. The challenges and future perspectives were also provided to promote supervision and disposal of domestic sewage from ships.

Measurement of High Protein Concentrations by Optical Rotation: A Case Study for Monitoring of Monoclonal Antibody Drug Downstream Processes.

BACKGROUND: Recent advancements in cell engineering and bioreactor engineering have enabled high monoclonal antibody (mAb) concentrations in harvested solutions for the downstream process (DSP).

Methods: As many unit operations such as capture chromatography, polish chromatography, membrane filtration, virus inactivation, virus filtration, and concentration by ultrafiltration are involved in DSP, it is crucial to monitor the process carefully in order to perform reliable and stable DSP operations. One of the most important signals (process parameter) to be monitored is the protein concentration CP. Although various methods are available, most of them are not suited for measuring high CP. In this paper, we have developed a method for measuring very high CP by optical rotation (OR).

Result: Linear correlations were confirmed between OR and Cp in the range CP = 0 to 80 g/L for mAbs with high repeatability and small variation coefficients. This method was applied to the monitoring of CP in the opaque (colored) solution during the cell culture. The CP by OR was in good agreement with those by the standard Protein A HPLC method.

Conclusion: Monitoring of high CP by OR is expected to be an efficient process analytical tool (PAT) for DSP.

Application of UV absorbance and electron-donating capacity as surrogates for micropollutant abatement during full-scale ozonation of secondary-treated wastewater.

Ozonation of secondary-treated wastewater for the abatement of micropollutants requires a reliable control of ozone doses. Changes in the UV absorbance of dissolved organic matter (DOM) during ozonation allow to estimate micropollutant abatement on-line and were therefore identified as feed-back control parameter. In this study, the suitability of the electron-donating capacity (EDC) as an additional surrogate parameter which is independent of optical DOM properties was evaluated during full-scale ozonation. For this purpose, a recently developed EDC analyzer was enhanced to enable continuous on-line EDC and UV absorbance measurements. During a multi-week monitoring campaign at the wastewater treatment plant of Zurich, Switzerland, specific ozone doses were varied from 0.13 to 0.91 mgO3⋅mgDOC-1 and selected micropollutants with different ozone reactivities were analyzed by LC-MS in conjunction with bromate analysis by IC-MS. In agreement with previous laboratory studies, the relative residual UV absorbance and EDC both decreased exponentially as a function of the specific ozone dose and, in comparison to the residual UV absorbance, residual EDC values showed a more pronounced decrease at low specific ozone doses ≤0.34 mgO3⋅mgDOC-1. Logistic regression models allowed to estimate relative residual micropollutant concentrations in the ozonation effluent using either the residual UV absorbance or EDC as explanatory variable. Averaging those models along the explanatory variables allowed to estimate target values in relative residual UV absorbances and EDC for specific micropollutant abatement targets. In addition, both parameters allowed to identify conditions with elevated conversions of bromide to bromate. Taken together, these findings show that the integration of relative residual EDC values as a second control parameter can improve existing absorbance-based ozonation control systems to meet micropollutant abatement targets, particularly for treatment systems where low ozone doses are applied.

Quantification of Raman-Interfering Polyoxoanions for Process Analysis: Comparison of Different Chemometric Models and a Demonstration on Real Hanford Waste.

The Hanford site represents a complicated environmental remediation challenge, remaining from the production of nuclear weapons. Over 100 million gallons of liquid radioactive waste of unknown composition will be chemically processed and vitrified, but the varying chemical composition and highly radioactive nature of the waste preclude the implementation of more developed, offline technologies to determine the composition. The only practical approach to waste treatment will require the significant utilization of real-time, chemometric modeling approaches. Although chemometric approaches have been applied to the analysis of Hanford waste, the models developed were highly tank-specialized, and limited discussion was provided on how models fared with interfering signals. As the tank waste is largely composed of oxoanions, which tend to have interfering Raman spectra, the general question was posed as to what chemometric approach is best suited to accurately quantify analytes in the presence of interfering signals. This was carried out by examining the ability of classical least square (CLS), principal component regression (PCR), partial least square (PLS), and locally weighted regression (LWR) to quantify NO3- and CO32- using their bands around 1050 cm-1. For all samples, the PLS-based model was found to be the most efficient approach from a model building and application perspective.

State estimation and nonlinear tracking control simulation approach. Application to a bioethanol production system.

Tracking control of specific variables is key to achieve a proper fermentation. This paper analyzes a fed-batch bioethanol production process. For this system, a controller design based on linear algebra is proposed. Moreover, to achieve a reliable control, on-line monitoring of certain variables is needed. In this sense, for unmeasurable variables, state estimators based on Gaussian processes are designed. Cell, ethanol and glycerol concentrations are predicted with only substrates measurement. Simulation results when the controller and estimators are coupled, are shown. Furthermore, the algorithms were tested with parametric uncertainties and disturbances in the control action, and are compared, in all cases, with neural networks estimators (previous work). Bayesian estimators show a performance improvement, which is reflected in a decrease of the total error. Proposed techniques give reliable monitoring and control tools, with a low computational and economic cost, and less mathematical complexity than neural network estimators.

Comparison of the new Cl2/O3/UV process with different ozone- and UV-based AOPs for wastewater treatment at pilot scale: Removal of pharmaceuticals and changes in fluorescing organic matter.

This work critically compared the removal of fluorescing PARAFAC components and selected pharmaceuticals (carbamazepine, fluoxetine, gemfibrozil, primidone, sulfamethoxazole, trimethoprim) from a tertiary wastewater effluent by different UV- and ozone-based advanced oxidation processes (AOPs) operated at pilot-scale. Investigated AOPs included UV/H2O2, UV/Cl2, O3, O3/UV, H2O2/O3/UV, and the new Cl2/O3/UV. AOPs comparison was accomplished using various ozone doses (0-9 mg/L), UV fluences (191-981 mJ/cm2) and radical promoter concentrations of Cl2 = 0.04 mM and H2O2 = 0.29 mM. Chlorine-based AOPs produced radical species that reacted more selectively with pharmaceuticals than radical species and oxidants generated by other AOPs. Tryptophan-like substances and humic-like fluorescing compounds were the most degraded components by all AOPs, which were better removed than microbial products and fulvic-like fluorescing substances. Removal of UV absorbance at 254 (UV254) nm was always low. Overall, chlorine-based AOPs were more effective to reduce fluorescence intensities than similar H2O2-based AOPs. The Cl2/O3/UV process was the most effective AOP to degrade all target micro-pollutants except primidone. On the other hand, the oxidation performance of pharmaceuticals by other ozone-based AOPs followed the order H2O2/O3/UV > O3/UV > O3. UV/Cl2 process outcompeted UV/H2O2 only for the removal of trimethoprim and sulfamethoxazole. Correlations between the removal of pharmaceuticals and spectroscopic indexes (PARAFAC components and UV254) had unique regression parameters for each compound, surrogate parameter and oxidation process. Particularly, a diverse PARAFAC component for each investigated AOP resulted to be the most sensitive surrogate parameter able to monitor small changes of pharmaceuticals removal.

Utilization of a Gas-Sensing System to Discriminate Smell and to Monitor Fermentation during the Manufacture of Oolong Tea Leaves.

The operational duration of shaking tea leaves is a critical factor in the manufacture of oolong tea; this duration influences the formation of its flavor and fragrance. The current method to control the duration of fermentation relies on the olfactory sense of tea masters; they monitor the entire process through their olfactory sense, and their experience decides the duration of shaking and setting. Because of this human factor and olfactory fatigue, it is difficult to define an optimum duration of shaking and setting; an inappropriate duration of shaking and setting deteriorates the quality of the tea. In this study, we used metal-oxide-semiconductor gas sensors to establish an electronic nose (E-nose) system and tested its feasibility. This research was divided into two experiments: distinguishing samples at various stages and an on-line experiment. The samples of tea leaves at various stages exhibited large differences in the level of grassy smell. From the experience of practitioners and from previous research, the samples could be categorized into three groups: before the first shaking (BS1), before the shaking group, and after the shaking group. We input the experimental results into a linear discriminant analysis to decrease the dimensions and to classify the samples into various groups. The results show that the smell can also be categorized into three groups. After distinguishing the samples with large differences, we conducted an on-line experiment in a tea factory and tried to monitor the smell variation during the manufacturing process. The results from the E-nose were similar to those of the sense of practitioners, which means that an E-nose has the possibility to replace the sensory function of practitioners in the future.

Stochastic simulation of phytoplankton biomass using eighteen years of daily data - predictability of phytoplankton growth in a large, shallow lake.

During the past decades, on-line monitoring of freshwater lakes has developed rapidly. To use high frequency time-series in lake management, novel models are needed that are simple and provide insight into the complexity of phytoplankton dynamics. Chlorophyll a (Chl), a proxy for phytoplankton biomass and environmental drivers were monitored on-line in large, shallow Lake Balaton during the vegetation periods between 2001 and 2018. Growth and non-growth (G and non-G) states of algae were deduced from daily change in Chl. Random forests (RF) were used to find stochastic response rules of phytoplankton to growth-supporting environmental habitat templates. The stochastic G/non-G state was translated into long-term daily biomass dynamics by a deterministic biomass model to assess uncertainty and to distinguish between inevitable and unpredictable blooms. A biomass peak was qualified as inevitable or unpredictable if the lower 95% confidence limit of simulations exceeded or remained at the baseline Chl level, respectively. Compared to a stochastic null model based on monthly Markovian transition probabilities, RF-based models captured wax and wane of biomass realistically. Timing of peaks could be better simulated than their magnitude, likely because habitat templates were primarily determined by light whereas peak sizes might depend on unmeasured processes, such as phosphorus availability. In general, algal growth was favored by wind-induced sediment resuspension that decreased light availability but simultaneously enhanced the P supply. Seasonal temperature and an integral of departures from the "normal" seasonal temperature over 2 to 3 generations were important drivers of phytoplankton growth, whereas short-term (diel and day to day) changes in water temperature appeared to be irrelevant. Four types of years could be distinguished during the study period with respect to algal growth conditions. The present modeling approach can reasonably be used even in highly variable aquatic environments when 3 to 4 years of daily data are available.

Use of Near-Infrared-Mid-Infrared Dual-Wavelength Spectrometry to Obtain Two-Dimensional Difference Spectra of Sesame Oil as Inactive Drug Ingredient.

The present study has investigated the transformation of sesame oil kept at low temperature during a definite period of time for refinement (called winterization) as an inactive drug ingredient by using two-dimensional difference spectra (2D-DS) analysis of spectra collected using a near-infrared (NIR) and mid-infrared (MIR) dual-wavelength spectrometer (NIR-MIR-DWS). The NIR and MIR spectra were measured nearly simultaneously from samples of sesame oil before and after winterization. The difference spectrum analysis of the obtained NIR-MIR data elucidated that, after the winterization process, the absorbances at peaks attributed to C=O, C=C, and OH groups decrease while the absorbances arising from the main chain (CH2) increase. The result indicated the removal of lignan and the fatty acids with relatively short main chains. Moreover, sesame oil unwinterized was cooled from room temperature to near 1 ℃ and subsequently warmed to room temperature. And the cycle was repeated two times. Real-time monitoring during the cooling and warming processes were carried out using the NIR-MIR-DWS. The prediction results obtained from partial least square calibration model for the temperature suggests that there are subtle differences in the oil composition between the first cooling process and after the warming and cooling cycle. For the more detailed analysis, the 2D-DS method is proposed. The results of the analyses using 2D-DS revealed that the starting point of the transformation is around 15 ℃. It can be estimated that sesame oil is mainly transformed by the first cooling down. Moreover, it was implied that the structure of methylene (CH2) was significantly related to the modifications in sesame oil with temperature change. A series of experimental results elucidated that the winterization of sesame oil removed its impurities and stabilized its conditions. These results are probably the first report on the effect of the winterization process on sesame oil.

Real-Time Monitoring of Volatile Compounds Losses in the Oven during Baking and Toasting of Gluten-Free Bread Doughs: A PTR-MS Evidence.

Losses of volatile compounds during baking are expected due to their evaporation at the high temperatures of the oven, which can lead to a decrease in the aroma intensity of the final product, which is crucial for gluten-free breads that are known for their weak aroma. Volatiles from fermentation and lipids oxidation are transferred from crumb to crust, and they flow out to the air together with Maillard and caramelisation compounds from the crust. In this study, the release to the oven of volatile compounds from five gluten-free breads (quinoa, teff and rice flours, and corn and wheat starches) and wheat bread during baking and toasting was measured in real-time using proton transfer reaction-time of flight-mass spectrometry (PTR-ToF-MS). Baking showed different volatile release patterns that are described by bell-shaped curves, plateaus and exponential growths. Flour-based breads had the higher overall volatile release during baking, but also high ratios in the final bread, while starch-based breads showed high pyrazine releases due to moisture losses. Meanwhile, toasting promoted the release of volatile compounds from the bread matrix, but also the additional generation of volatiles from Maillard reaction and caramelisation. Interestingly, gluten-free breads presented higher losses of volatiles during baking than wheat bread, which could partially explain their weaker aroma.