Electropenetrography Study of Euschistus heros (F.) (Heteroptera: Pentatomidae) Nymphs Feeding on Vegetative Soybean Structures.

The study aimed to understand the feeding behavior of Neotropical brown stink bug nymphs Euschistus heros (F.) on soybean plants during vegetative stage through electropenetrography (EPG) technique. Three distinct phases were identified: non-feeding, pathway, and ingestion. Waveforms representing these phases were consistent across nymphal instars and plant structures, and named Np, Eh1, and Eh2, respectively. Biological interpretations of the waveforms were proposed by integrating visual observations, comparisons with adult waveforms, and histological studies. The waveforms Np, Eh1, and Eh2 were associated with resting/walking, initial stylet-plant contact, and xylem sap ingestion, respectively. Notably, nymphs showed a higher number of Eh1 events and longer durations when feeding on petioles compared to leaves, particularly in younger instars. However, differences between instars diminished in older nymphs. Fifth instars consistently exhibited the highest Eh1 values, and displayed longer xylem ingestion durations compared to other instars. Second instars demonstrated increased xylem ingestion events on petioles compared to leaves. Across plant structures, on petioles, nymphs generally showed longer xylem ingestion durations than on leaf surfaces. Fifth instar consistently had the longest ingestion durations overall. Additionally, statistical differences in xylem ingestion duration were observed between instars within each plant structure, with fifth instars displaying the longest durations. These findings offer valuable insights into the feeding behavior of E. heros nymphs, which could inform the development of more effective pest management strategies for soybean crops.

Waveform load analysis for fatigue in the printed PLA.

Additive manufacturing is fast becoming a key process to manufacture a customized design with complex geometry and one process usually employed is based on the fused filament fabrication. Up to now this method is typically employed for rapid prototyping, it is therefore their mechanical strength is lower than the components manufactured using conventional casting process. It is well known that most failures are happened under repeated loads; therefore, a functional component mandatory needs to reach endurance strength under cyclic loads. Hence, this study set out to clarify several aspects of filament fused test specimens to determine their effect on accumulated damage to then predict component life under repeated loads. In this study is considered three waveforms such as sinusoidal, triangular and square, where it is observed that the square waveform provides the most severe loads. This study therefore makes a major contribution to research on the fatigue properties of parts manufactured using fused filament by reporting their fatigue behaviour under different fatigue load conditions. It would give a better understanding to improve the mechanical prediction of PLA, thereby it might be used to manufacture a functional component instead of only a prototype or spare part.

Histogram of Gradient Orientations of Signal Plots Applied to P300 Detection.

The analysis of Electroencephalographic (EEG) signals is of ulterior importance to aid in the diagnosis of mental disease and to increase our understanding of the brain. Traditionally, clinical EEG has been analyzed in terms of temporal waveforms, looking at rhythms in spontaneous activity, subjectively identifying troughs and peaks in Event-Related Potentials (ERP), or by studying graphoelements in pathological sleep stages. Additionally, the discipline of Brain Computer Interfaces (BCI) requires new methods to decode patterns from non-invasive EEG signals. This field is developing alternative communication pathways to transmit volitional information from the Central Nervous System. The technology could potentially enhance the quality of life of patients affected by neurodegenerative disorders and other mental illness. This work mimics what electroencephalographers have been doing clinically, visually inspecting, and categorizing phenomena within the EEG by the extraction of features from images of signal plots. These features are constructed based on the calculation of histograms of oriented gradients from pixels around the signal plot. It aims to provide a new objective framework to analyze, characterize and classify EEG signal waveforms. The feasibility of the method is outlined by detecting the P300, an ERP elicited by the oddball paradigm of rare events, and implementing an offline P300-based BCI Speller. The validity of the proposal is shown by offline processing a public dataset of Amyotrophic Lateral Sclerosis (ALS) patients and an own dataset of healthy subjects.

Electropenetrography (EPG): a Breakthrough Tool Unveiling Stink Bug (Pentatomidae) Feeding on Plants.

In this article, we review and discuss the potential use of EPG (electropenetrography) as a powerful tool to unveil the feeding process of phytophagous stink bugs (pentatomids). These bugs are relatively big and vigorous, which presents a problem during wiring (i.e., attachment of the gold wire on the bug's pronotum) for use in EPG. Once this challenge was overcome, using the sand paper-and-wire technique, several species have been studied using EPG, yielding waveforms that, coupled with histological studies, revealed the ingestion sites on different host plants. These sites include vascular tissues (xylem and phloem), parenchyma tissue, and seed endosperm. Stink bugs usually feed by secreting a gelling saliva to create a salivary sheath that surrounds the stylets and anchors/supports/lubricates them. However, using the cell rupture feeding strategy and the tactic of combined laceration (mechanical movements of the stylets) and maceration (action of chemical enzymes) breaks the plant cells enabling ingestion. The number of ingestion events and their duration is variable according to the feeding site. Waveforms generated have typical patterns according to the feeding site. Recent studies with several species of stink bugs have started to demonstrate the potential of EPG as a tool to unveil their feeding behavior. This may also be useful in the applied field of stink bug management, such as the development and screening of resistant genotypes and the action of chemical insecticides affecting their feeding and survivorship.

Ability of ICU Health-Care Professionals to Identify Patient-Ventilator Asynchrony Using Waveform Analysis.

BACKGROUND: Waveform analysis by visual inspection can be a reliable, noninvasive, and useful tool for detecting patient-ventilator asynchrony. However, it is a skill that requires a properly trained professional. METHODS: This observational study was conducted in 17 urban ICUs. Health-care professionals (HCPs) working in these ICUs were asked to recognize different types of asynchrony shown in 3 evaluation videos. The health-care professionals were categorized according to years of experience, prior training in mechanical ventilation, profession, and number of asynchronies identified correctly. RESULTS: A total of 366 HCPs were evaluated. Statistically significant differences were found when HCPs with and without prior training in mechanical ventilation (trained vs non-trained HCPs) were compared according to the number of asynchronies detected correctly (of the HCPs who identified 3 asynchronies, 63 [81%] trained vs 15 [19%] non-trained, P < .001; 2 asynchronies, 72 [65%] trained vs 39 [35%] non-trained, P = .034; 1 asynchrony, 55 [47%] trained vs 61 [53%] non-trained, P = .02; 0 asynchronies, 17 [28%] trained vs 44 [72%] non-trained, P < .001). HCPs who had prior training in mechanical ventilation also increased, nearly 4-fold, their odds of identifying ≥2 asynchronies correctly (odds ratio 3.67, 95% CI 1.93-6.96, P < .001). However, neither years of experience nor profession were associated with the ability of HCPs to identify asynchrony. CONCLUSIONS: HCPs who have specific training in mechanical ventilation increase their ability to identify asynchrony using waveform analysis. Neither experience nor profession proved to be a relevant factor to identify asynchrony correctly using waveform analysis.

High-speed Videolaryngoscopy: Quantitative Parameters of Glottal Area Waveforms and High-speed Kymography in Healthy Individuals.

OBJECTIVES: We conducted a study to obtain quantitative parameters of the vocal dynamic using high-speed videolaryngoscopy and to characterize the vocal fold vibration pattern of healthy individuals by analyzing glottal area waveforms and high-speed kymography. METHODS: Laryngeal images of 45 healthy individuals were captured using high-speed videolaryngoscopy. The open and speed quotients of the glottal area waveforms and high-speed kymography were obtained and statistically analyzed according to the gender of each individual. RESULTS: Glottal area waveforms revealed average values of 0.85 and 1.16 for open and speed quotients, respectively, for women, and 0.70 and 1.19 for men. Using high-speed kymography, quantitative parameters of open and speed quotients for women were 0.62 and 1.02, respectively, and for men were 0.57 and 1.12. By gender, a significant statistical difference emerged for open quotients obtained from both glottal area waveforms (P = 0.004) and high-speed kymography (P = 0.013). CONCLUSION: Obtained by using computational tools specifically for analyzing laryngeal images from high-speed videolaryngoscopy, quantitative parameters of glottal area waveforms and high-speed kymography in healthy individuals provide reference data and normality for future studies.

Determinación de la Rigidez Arterial Empleando Simulación Computacional / Determination of Arterial Stiffness Using Computational Simulation

El incremento de la rigidez arterial está asociado con el desarrollo de enfermedades cardiovasculares, las cuales constituyen una de las principales causas de muertes en el mundo. Por este motivo el desarrollo de métodos no invasivos que permitan cuantificar la rigidez arterial ha alcanzado un gran impacto. En este trabajo se estudia el método no invasivo de medición de la velocidad de la onda del pulso de la arteria braquial al tobillo (baPWV), por sus siglas en inglés. Para estudiar este método se simularon las formas de ondas de presión en el sistema arterial empleando un modelo unidimensional, a partir de las cuales se determinaron los valores de baPWV. Estos valores fueron comparados con los calculados por otros dos métodos: cfPWV (velocidad de la onda del pulso entre la carótida y la femoral, el método estándar) y PWVteor (ecuación de Bramwell-Hill), obteniéndose correlaciones significativas, r=0.967 y r=0.9828 respectivamente. Se investigó la sensibilidad del método baPWV a la variación de la rigidez, representada por la variación de la distensibilidad y, se concluyó que el método es sensible a los cambios de rigidez que ocurren tanto en las arterias centrales como en las arterias periféricas.

The arterial stiffness increased is associated with the development of cardiovascular diseases, which constitute one of the first causes of death globally. For this reason the development of noninvasive methods to quantify arterial stiffness have had great impact. The purpose of this paper is the study of the noninvasive measurement method of brachial ankle pulse wave velocity (baPWV). To perform this study pressure waveforms in the arterial system were simulated, by using a one-dimensional model. With these pressure waveforms baPWV's values were calculated, and were compared with two others calculated methods: cfPWV (carotid-femoral PWV, gold standard method), and PWVteor (Bramwell-Hill equation). Significant correlations were obtained, r=0.967 y r=0.9828 respectively. The sensibility of the baPWV method to the stiffness change, represented for the distensibility change, was investigated, and we conclude that baPWV method is sensitive to the changes that take place in both central and peripheral arteries.