Surface guided radiation therapy with an innovative open-face mask and mouth bite: patient motion management in brain stereotactic radiotherapy.

INTRODUCTION: To guarantee treatment reproducibility and stability, immobilization devices are essential. Additionally, surface-guided radiation therapy (SGRT) serves as an accurate complement to frameless stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT) by aiding patient positioning and real-time monitoring, especially when non-coplanar fields are in use. At our institute, we have developed a surface-guided SRS (SG-SRS) workflow that incorporates our innovative open-face mask (OM) and mouth bite (MB) to guarantee a precise and accurate dose delivery. METHODS: This study included 40 patients, and all patients were divided into closed mask (CM) and open-face mask (OM) groups according to different positioning flow. Cone beam computed tomography (CBCT) scans were performed, and the registration results were recorded before and after the treatment. Then Bland-Altman method was used to analyze the consistency of AlignRT-guided positioning errors and CBCT scanning results in the OM group. The error changes between 31 fractions in one patient were recorded to evaluate the feasibility of monitoring during treatment. RESULTS: The median of translation error between stages of the AlignRT positioning process was (0.03-0.07) cm, and the median of rotation error was (0.20-0.40)°, which were significantly better than those of the Fraxion positioning process (0.09-0.11) cm and (0.60-0.75)°. The mean bias values between the AlignRT guided positioning errors and CBCT were 0.01 cm, - 0.07 cm, 0.03 cm, - 0.30°, - 0.08° and 0.00°. The 31 inter-fractional errors of a single patient monitored by SGRT were within 0.10 cm and 0.50°. CONCLUSIONS: The application of the SGRT with an innovative open-face mask and mouth bite device could achieve precision positioning accuracy and stability, and the accuracy of the AlignRT system exhibits excellent constancy with the CBCT gold standard. The non-coplanar radiation field monitoring can provide reliable support for motion management in fractional treatment.

Proposal of Design and Innovation in the Creation of the Internet of Medical Things Based on the CDIO Model through the Methodology of Problem-Based Learning.

The educational framework-Conceive, Design, Implement, and Operate-is part of an international proposal to improve education in the field of engineering, emphasizing how to teach engineering comprehensively, which allows the standardization of skills in professionals as a model for teaching engineering. Moreover, problem-based learning allows students to experiment with challenging situations through cases that simulate natural contexts with their profession. The integration of these two education strategies applied to the Internet of Things (IoT) Education for Industry 4.0 has promoted the generation of teaching challenges. Our education strategy proposes the synergy between laboratory guides and the classroom with the following actions: the content of the topic is presented, followed by the presentation of an issue focused into a realistic context, with practical exercises integrating software and hardware for the deployment of the solution to be reported as a final project. Moreover, undergraduate students in the biomedical engineering area acquired new knowledge about IoT, but at the same time, they may develop skills in the field of programming and structuring different architectures to solve real-world problems. Finally, traditional models of education require new teaching initiatives in the field of biomedical engineering concerning the current challenges and needs of the labor market.

Real-time monitoring of Metridia luciferase release from cells upon interaction with model toxic substances by a fully automatic flow setup - A proof of concept.

This manuscript reports on a fully automatic sequential injection system incorporating a 3D printed module for real-time monitoring of the release of Metridia luciferase from a modified liver epithelial cell line. To this end, a simple and effective approach for the automation of flash-type chemiluminescence assays was developed. The 3D printed module comprised an apical and a basal compartment that enabled monitoring membrane processes on both sides of the cell monolayer aimed at elucidating the direction of luciferase release. A natural release was observed after transfection with the luciferase plasmid by online measurement of the elicited light from the reaction of the synthesized luciferase with the coelenterazine substrate. Model substances for acute toxicity from the group of cholic acids - chenodeoxycholic and deoxycholic acids - were applied at the 1.0 and 0.5 mmol L-1 levels. The tested cholic acids caused changes in cell membrane permeability that was accompanied by an increased luciferase release. The obtained kinetic profiles were evaluated based on the delay between the addition of the toxic substance and the increase of the chemiluminescence signal. All experiments were carried out in a fully automatic system in ca. 5 min per sample in 30 min intervals and no manual interventions were needed for a sampling period of at least 6 h.

The impact of body size on Aedes [Stegomyia] aegypti wingbeat frequency: implications for mosquito identification.

Billions of people are at risk due to mosquito-borne diseases. Ideally, the control of mosquito-borne diseases should integrate mosquito control and surveillance to maximize transmission prevention while minimizing environmental impacts. Mosquito surveillance is often limited in scope by logistical constraints, especially the labour and expertise in identifying captured mosquitoes. Mosquito sounds, primarily the wingbeat frequencies (WBF), have been extensively studied in the literature, often targeting a straightforward assessment of this technology with species identification in laboratory conditions. Optical sensors for measuring the WBF of free-flying mosquitoes are the most recent proposal to automate species identification. However, many of the factors that may influence WBF within and between species have not been fully examined, resulting in failures in the species identification. Here we show that body size and temperature modify the wingbeat frequency of female Aedes [Stegomyia] aegypti Linnaeus (Diptera:Culicidae) and such an optical sensor can capture these alterations. We demonstrate that this study's optical sensor can distinguish wingbeat frequency from large and small mosquitoes at different temperatures. The relationship between WBF and size should be taken into account to improve the accuracy of devices that automatically identify species using WBF.

Real time monitoring of in situ generated hydrogen peroxide in electrochemical advanced oxidation reactors using an integrated Pt microelectrode.

This work propose the fabrication and characterization of a Pt microelectrode integrated with a silver quasi-reference counter electrode (Pt/AgQRCE) for real time amperometric measurements of hydrogen peroxide electrochemically generated by water oxidation on Nb-supported boron doped diamond (Ni/BDD) anode. The developed electroanalytical method requires a very small sample volume and has higher sensitivity when compared to the conventional spectrophotometric analysis using ammonium metavanadate. The experiments were performed with Nb/BDD anode applying current densities of 30, 60, 90 and 120 mA cm-2 in 0.10 mol L-1 HClO4 supporting electrolyte showed that H2O2 production increase in the first 90 min of electrolysis and then reaches a plateau in both off-line and real time measurements. For the first 90 min, the electrogeneration of H2O2 exhibited a pseudo zero-order kinetics. The results obtained by the electrochemical amperometric analysis were compared to a spectrophotometric methodology reported on the literature and, at 95% confidence level the two methods do not demonstrated significant difference.

All Single-Mode-Fiber Supercontinuum Source Setup for Monitoring of Multiple Gases Applications.

In this paper, a gas sensing system based on a conventional absorption technique using a single-mode-fiber supercontinuum source (SMF-SC) is presented. The SC source was implemented by channeling pulses from a microchip laser into a one kilometer long single-mode fiber (SMF), obtaining a flat high-spectrum with a bandwidth of up to 350 nm in the region from 1350 to 1700 nm, and high stability in power and wavelength. The supercontinuum radiation was used for simultaneously sensing water vapor and acetylene gas in the regions from 1350 to 1420 nm and 1510 to 1540 nm, respectively. The experimental results show that the absorption peaks of acetylene have a maximum depth of approximately 30 dB and contain about 60 strong lines in the R and P branches, demonstrating a high sensitivity of the sensing setup to acetylene. Finally, to verify the experimental results, the experimental spectra are compared to simulations obtained from the Hitran database. This shows that the implemented system can be used to develop sensors for applications in broadband absorption spectroscopy and as a low-cost absorption spectrophotometer of multiple gases.

In situ cell differentiation monitoring of Catharanthus roseus suspension culture processes by NIR spectroscopy.

Plant suspension culture is attracting interest as a promising platform to produce biological medicines due to the absence of virus, prions or DNA related to mammals during the production process. However, the heterogenic plant cell proliferation nature is particularly challenging for establishing industrial processes based on innovative approaches currently used, particularly in the animal cell culture industry. In this context, while Process Analytical Technology (PAT) tools have been used to monitor classical parameters such as biomass dry weight, its use in cells heterogeneity has received limited attention. Therefore, the feasibility of in situ monitoring of cell differentiation in plant cell suspensions employing NIR spectroscopy and chemometrics was investigated. Off-line measurements of cell heterogeneity in term of cell differentiation and in-line NIR spectra captured in 3 L bioreactor cultures were employed to generate calibration models. Then models were tested to estimate the population distribution of parenchyma, collenchyma and sclerenchyma cells during Catharanthus roseus suspension cultures. Results have proven in situ NIR spectroscopy as a capable PAT tool to monitor differentiated cells accurately and in real-time. These results are the starting point to follow-up PAT systems so that plant cell culture heterogeneity may be better understood and controlled in biopharmaceutical plant cell cultures.

Real-Time and Simultaneous Monitoring of NO, NO2, and N2O Using Substrate-Integrated Hollow Waveguides Coupled to a Compact Fourier Transform Infrared (FT-IR) Spectrometer.

Nitrogen-based fertilizers have been used in modern agricultural activities resulting in a relevant emission source of nitrogen gases into the atmosphere, mainly nitric oxide (NO), nitrogen dioxide (NO2), and nitrous oxide (N2O). Furthermore, the burning of fossil fuels is the most significant emission source of NOx (i.e., NO + NO2), being the controlling of vehicle exhaust system an essential task. Those compounds can be related to air pollution effects either directly, by emitting a powerful greenhouse gas (i.e., N2O), or indirectly, by formation of nitric acid (HNO3) or ammonium nitrate (NH4NO3) from NO or NO2, responsible for the increase of acid rain and particulate material into the atmosphere. This context requires appropriate sensor technology facilitating in situ and simultaneous monitoring of nitrogen emitted gases, with easiness of operation and compact dimensions. In this communication, we describe an innovative mid-infrared chemical sensor platform for the in situ, real-time, and simultaneous quantification of gaseous NO, NO2, and N2O by combining a compact Fourier transform infrared (FT-IR) spectrometer with the so-called substrate-integrated hollow waveguide (iHWG) as a miniaturized gas cell. The optical platform enabled limits of detection of 10, 1, and 0.5 ppm of NO, NO2, and N2O, respectively. The linear concentration range evaluated in this study is suitable for the application of the sensing platform in vehicle exhaust air samples. Given the high adaptability of the developed infrared sensing device toward preconcentration or ultraviolet conversion modules and also considering the potential for combining tunable interband cascade lasers (ICLs) in lieu of the FT-IR spectrometer, we anticipate the application of the sensing platform for in situ determination of nitrogen gases in a wide range of scenarios.

Kinetic spectrophotometric method for real-time monitoring of ultraviolet photoreactions: A mini-photoreactor.

It is proposed a new approach to evaluate the performance of ultraviolet photoreactions by integrating UV-LED and a UV-Vis cuvette as a mini-reactor for kinetic monitoring in a spectrophotometer not influenced by external light. This system uses only 3.0 mL of solutions in a rectangular quartz cuvette with a mini-bar magnetic stirrer in a cell holder and a UV-LED of 5 W with λmax at 370 nm was positioned on the top of the cuvette and maintained at 25.0 oC. The effectiveness of this photoreactor was demonstrated by measuring the real-time degradation of two model compounds, salicylic acid and methylene blue, in homogeneous and heterogenous systems. Photolysis of MB with H2O2 results in increasing of rate constants as [H2O2] increased. Heterogeneous photocatalysis of MB and SA was fastest achieved in ZnO dosage of 0,20 g.L-1. This mini-photoreactor allows monitoring the real-time kinetic performance collecting almost a thousand points in each experiment, leading to accurate rate constants. Moreover, this system presented positive environmental aspects such as: lower reactants and catalyst amounts, lower cost and waste amounts, use of the UV-LED radiation and labor time saving. This is a novel approach to determine the photoreaction effectiveness and it can be applied to systematic studies especially for the kinetic parameter determinations.

Real-time monitoring of a coffee roasting process with near infrared spectroscopy using multivariate statistical analysis: A feasibility study.

This work proposes the use of near infrared (NIR) spectroscopy in diffuse reflectance mode and multivariate statistical process control (MSPC) based on principal component analysis (PCA) for real-time monitoring of the coffee roasting process. The main objective was the development of a MSPC methodology able to early detect disturbances to the roasting process resourcing to real-time acquisition of NIR spectra. A total of fifteen roasting batches were defined according to an experimental design to develop the MSPC models. This methodology was tested on a set of five batches where disturbances of different nature were imposed to simulate real faulty situations. Some of these batches were used to optimize the model while the remaining was used to test the methodology. A modelling strategy based on a time sliding window provided the best results in terms of distinguishing batches with and without disturbances, resourcing to typical MSPC charts: Hotelling's T2 and squared predicted error statistics. A PCA model encompassing a time window of four minutes with three principal components was able to efficiently detect all disturbances assayed. NIR spectroscopy combined with the MSPC approach proved to be an adequate auxiliary tool for coffee roasters to detect faults in a conventional roasting process in real-time.

Real Time Monitoring of Children, and Adults with Mental Disabilities Using a Low-Cost Non-Invasive Electronic Device.

There are a growing number of small children-as well as adults-with mental disabilities (including elderly citizens with Alzheimer's disease or other forms of age-related dementia) that are getting lost in rural and urban areas for various reasons. Establishing their location within the first 72 h is crucial because lost people are exposed to all kinds of adverse conditions and in the case of the elderly, this is further aggravated if prescribed medication is needed. Herein we describe a non-invasive, low-cost electronic device that operates constantly, keeping track of time, the geographical location and the identification of the subject using it. The prototype was made using commercial low-cost electronic components. This electronic device shows high connectivity in open and closed areas and identifies the geographical location of a lost subject. We freely provide the software and technical diagrams of the prototypes.

Application of In-Line Mid-Infrared (MIR) Spectroscopy Coupled with Calorimetry for the Determination of the Molar Enthalpy of Reaction between Ammonium Chloride and Sodium Nitrite.

The reaction between ammonium chloride and sodium nitrite has been known for its application as a source of heat because of its large enthalpy of reaction, for which it has been used by the oil industry. There have been no known calorimetric studies for the experimental determination of its molar enthalpy of reaction, which is necessary in order to predict the limits achieved for up-scale applications. Attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR) and reaction calorimetry were used to determine this value by using a simple methodology. Both techniques were used concomitantly as a source of information regarding the time-dependent moles converted (Δn) and the amount of exchanged heat (ΔH). The molar enthalpy of reaction was calculated to be -74 ± 4 kcal mol(-1). The percentage between the confidence interval and the calculated value was 5.4%, which shows that the methodology was precise. After the determination of the molar enthalpy of reaction, it was proved that the ATR FT-IR alone was able to be used as a substitute for the reaction calorimetry technique, in which the IR signal is converted to the heat information, presenting as an easier technique for the monitoring of the heat released by this system for future applications.

New approach for natural products screening by real-time monitoring of hemoglobin hydrolysis using quartz crystal microbalance.

The hemoglobin (Hb) released from erythrocytes is a primary nutritive component for many blood-feeding parasites. The aspartic protease cathepsin D is a hemoglobinase that is involved in the Hb degradation process and is considered an interesting target for chemotherapy intervention. However, traditional enzymatic assays for studying Hb degradation utilize spectrophotometric techniques, which do not allow real-time monitoring and can present serious interference problems. Herein, we describe a biosensor using simple approach for the real-time monitoring of Hb hydrolysis as well as an efficient screening method for natural products as enzymatic inhibitors using a quartz crystal microbalance (QCM) technique. Hemoglobin was anchored on the quartz crystal surface using mixed self-assembled monolayers. The addition of the enzyme caused a mass change (frequency shift) due to Hb hydrolysis, which was monitored in real time. From the frequency change patterns of the Hb-functionalized QCM, we evaluated the enzymatic reaction by determining the kinetic parameters of product formation (k(cat)). The QCM enzymatic assay using immobilized human Hb was shown to be an excellent approach for screening possible inhibitors in complex mixtures, opening up a new avenue for the discovery of novel inhibitors.