Onset Point Research Articles

Onset of pain to surgery time in acute aortic dissections type A: a mandatory factor for evaluating surgical results?

An acute aortic dissection type A (AADA) is a rare but life-threatening event. The mortality rate ranges between 18% to 28% and mortality is often within the first 24 h and up to 1%-2% per hour. Although the onset of pain to surgery time has not been a relevant factor in terms of research in the field of AADA, we hypothesize that a patient's preoperative conditions depend on the length of this time. Between January 2000 and January 2018, 430 patients received surgical treatment for acute aortic dissection DeBakey type I at our tertiary referral hospital. In 11 patients, the exact time point of initial onset of pain was retrospectively not detectable. Accordingly, a total of 419 patients were included in the study. The cohort was categorized into two groups: Group A with an onset of pain to surgery time < 6 h (n = 211) and Group B > 6 h (n = 208), respectively. Median age was 63.5 years (y) ((IQR: 53.3-71.4 y); (67.5% male)). Preoperative conditions differed significantly between the cohorts. Differences were detected in terms of malperfusion (A: 39.3%; B: 23.6%; P: 0.001), neurological symptoms (A: 24.2%; B: 15.4%; P: 0.024), and the dissection of supra-aortic arteries (A: 25.1%; B: 16.8%; P: 0.037). In particular, cerebral malperfusion (A 15.2%: B: 8.2%; P: 0.026) and limb malperfusion (A: 18%, B: 10.1%; P: 0.020) were significantly increased in Group A. Furthermore, Group A showed a decreased median survival time (A: 1,359.0 d; B: 2,247.5 d; P: 0.001), extended ventilation time (A: 53.0 h; B: 44.0 h; P: 0.249) and higher 30-day mortality rate (A: 25.1%; B: 17.3%; P: 0.051). Patients with a short onset of pain to surgery time in cases of AADA present themselves not only with more severe preoperative symptoms but are also the more compromised cohort. Despite early presentation and emergency aortic repair, these patients show increased chances of early mortality. The "onset of pain to surgery time" should become a mandatory factor when making comparable surgical evaluations in the field of AADA.

Optical study of knocking phenomenon in a spark-ignition engine by using high-speed OH* chemiluminescence imaging: A multiple ignition sites approach

Knock in a spark-ignition (SI) engine is a complicated combustion phenomenon that stimulates high-pressure oscillations inside the combustion chamber and restricts engine performance. This study presents a high-speed OH* chemiluminescence imaging technique to investigate the knock mechanism resulting from firing multiple spark plugs. The experiment was performed using a customized liner having three spark plugs installed at equal spacing, and to compare the results with conventional SI conditions, in which one spark plug was mounted at the center of the cylinder head. In addition, multiple pressure transducers were used at various locations to record the frequencies induced by the pressure oscillations inside the cylinder during knocking events. The results showed that firing a single central spark plug generated mild knock with late combustion phasing and lower power output. However, adding more spark plugs could advance the initiation of autoignition and produce higher knock intensity along with lower combustion duration for the same operating conditions. Additionally, a weak OH* chemiluminescence intensity oscillation was monitored before the autoignition of the unburned charge occurred. The crank angle location of peak OH* intensity and peak HRR showed a good linear curve fit with a positive slope. Furthermore, the larger amount of unburned mass fraction produced stronger pressure waves due to multiple autoignition sites, and the unburned mass fraction exhibited a good linear relationship with unburned temperature and end-gas area at the knock onset point. Moreover, the frequency spectrum recorded by the multiple pressure sensors illustrated that in the case of a single central spark plug only circumferential acoustic waves were formed with low power intensity. However, multiple ignition sites promoted both circumferential and radial pressure waves inside the combustion chamber because of multiple autoignitions occurring both near the center and cylinder wall.

Predictors of clinical outcomes in space-occupying cerebellar infarction undergoing suboccipital decompressive craniectomy.

Despite current clinical guidelines recommending suboccipital decompressive craniectomy (SDC) in cerebellar infarction when patients present with neurological deterioration, the precise definition of neurological deterioration remains unclear and accurate timing of SDC can be challenging. The current study aimed at characterizing whether clinical outcomes can be predicted by the GCS score immediately prior to SDC and whether higher GCS scores are associated with better clinical outcomes. In a single-center, retrospective analysis of 51 patients treated with SDC for space-occupying cerebellar infarction, clinical and imaging data were evaluated at the time points of symptom onset, hospital admission, and preoperatively. Clinical outcomes were measured by the mRS. Preoperative GCS scores were stratified into three groups (GCS, 3-8, 9-11, and 12-15). Univariate and multivariate Cox regression analyses were performed using clinical and radiological parameters as predictors of clinical outcomes. In cox regression analysis GCS scores of 12-15 at surgery were significant predictors of positive clinical outcomes (mRS, 1-2). For GCS scores of 3-8 and 9-11, no significant increase in proportional hazard ratios was observed. Negative clinical outcomes (mRS, 3-6) were associated with infarct volume above 6.0 cm3, tonsillar herniation, brainstem compression, and a preoperative GCS score of 3-8 [HR, 2.386 (CI, 1.160-4.906); p = 0.018]. Our preliminary findings suggest that SDC should be considered in patients with infarct volumes above 6.0 cm3 and with GCS between 12 and 15, as these patients may show better long-term outcomes than those in whom surgery is delayed until a GCS score below 11.

Interrelationship of bulk and oil-water interfacial properties of asphaltenes

Prediction and control of the behavior of asphaltenes have always been one of the most challenging topics in the oil and gas industry. To this aim, many attempts have been done so far to scrutinize the behavior of the asphaltenes in the bulk and at the oil/water interfaces. However, still more comprehensive knowledge about the relationships between the bulk and interfacial properties of the asphaltenes is required. In this study, the changes in the surface behavior of the asphaltenes upon aromaticity variation in the bulk are investigated. For this purpose, dynamic light scattering (DLS) experiments are accompanied by dynamic interfacial tension (IFT), and interfacial rheology measurements to analyze the asphaltene aggregates size, mobility, and surface activity upon a change in the bulk aromaticity. A wide range of aromatic conditions was used to cover possible changes in asphaltene behavior before and after the onset point. The results revealed that the interfacial activity and the structure of the adsorbed layers of the asphaltenes are significantly influenced by the bulk properties. Low aromaticity conditions led to an increase in asphaltene surface activity and changed the dilational rheological parameters considerably. For instance, the results illustrate the instantaneous elasticity of about 40 mN/m (around 0.08 Hz) for 500 mg/L asphaltene in heptol (50–50) while for the toluene sample, this value is reduced to about 30 mN/m and occurs at higher frequencies (about 0.12 Hz). Moreover, the results demonstrated the importance of the aging time on the measured parameters, particularly for the samples beyond the onset point. Our findings also showed the importance of dynamic interfacial data over static ones. Finally, by applying the concept of diffusion coefficient, it can be assumed that only a small portion of the asphaltenes are practically surface-active, and their surface activity is directly correlated with the aromaticity of the solution.

Modeling individual differences in the timing of change onset and offset.

Individual differences in the timing of developmental processes are often of interest in longitudinal studies, yet common statistical approaches to modeling change cannot directly estimate the timing of when change occurs. The time-to-criterion framework was recently developed to incorporate the timing of a prespecified criterion value; however, this framework has difficulty accommodating contexts where the criterion value differs across people or when the criterion value is not known a priori, such as when the interest is in individual differences in when change starts or stops. This article combines aspects of reparameterized quadratic models and multiphase models to provide information on the timing of change. We first consider the more common situation of modeling decelerating change to an offset point, defined as the point in time at which change ceases. For increasing trajectories, the offset occurs when the criterion attains its maximum ("inverted J-shaped" trajectories). For decreasing trajectories, offset instead occurs at the minimum. Our model allows for individual differences in both the timing of offset and ultimate level of the outcome. The same model, reparameterized slightly, captures accelerating change from a point of onset ("J-shaped" trajectories). We then extend the framework to accommodate "S-shaped" curves where both the onset and offset of change are within the observation window. We provide demonstrations that span neuroscience, educational psychology, developmental psychology, and cognitive science, illustrating the applicability of the modeling framework to a variety of research questions about individual differences in the timing of change. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Strain controlled shear hardening behavior in suspensions of alumina spheres in a polydimethylsiloxane oligomer matrix

AbstractAs a model system for thermal interface materials (TIMs), the complex rheological behavior of polydimethylsiloxane oligomer (oDMS)/alumina sphere particles (AlS) suspensions (i.e., oDMS/AlS) is investigated systematically in this work. Aluminum particles with 1 and 10 μm were used as fillers. Here, a surface treatment by using a silane coupling agent as found to be effective in improving the fluidity of the suspensions with small sized AlS particles. Peculiar large amplitude oscillatory shear (LAOS) results were observed for the suspensions that exhibited three or four responses (Hookean regime, shear softening, shear hardening and a second shear softening) depending on the surface properties of AlS particles. For the oDMS/AlS10 neat system, the width of the Hookean regime is determined by the shear stress () instead of the shear strain (), whereas it completely disappears in the oDMS/AlS10t system due to the increase potential energy between particles. Both critical stress and strain at the onset point for strain hardening decreased with the increase of particle concentration. Frequency dependent measurements illustrates that it is the critical strain instead of the stress that controls the shear hardening behavior. Average distance of neighboring particles is assumed to play a key role in the formation of hydroclusters.

MicroRNAs as Biomarkers of Endothelial Dysfunction and Therapeutic Target in the Pathogenesis of Atrial Fibrillation.

The pathophysiology of atrial fibrillation (AF) may involve atrial fibrosis/remodeling and dysfunctional endothelial activities. Despite the currently available treatment approaches, the progression of AF, its recurrence rate, and the high mortality risk of related complications underlay the need for more advanced prognostic and therapeutic strategies. There is increasing attention on the molecular mechanisms controlling AF onset and progression points to the complex cell to cell interplay that triggers fibroblasts, immune cells and myofibroblasts, enhancing atrial fibrosis. In this scenario, endothelial cell dysfunction (ED) might play an unexpected but significant role. microRNAs (miRNAs) regulate gene expression at the post-transcriptional level. In the cardiovascular compartment, both free circulating and exosomal miRNAs entail the control of plaque formation, lipid metabolism, inflammation and angiogenesis, cardiomyocyte growth and contractility, and even the maintenance of cardiac rhythm. Abnormal miRNAs levels may indicate the activation state of circulating cells, and thus represent a specific read-out of cardiac tissue changes. Although several unresolved questions still limit their clinical use, the ease of accessibility in biofluids and their prognostic and diagnostic properties make them novel and attractive biomarker candidates in AF. This article summarizes the most recent features of AF associated with miRNAs and relates them to potentially underlying mechanisms.

Evolution of Poisson’s Ratio in the Tension Process of Low-Carbon Hot-Rolled Steel with Discontinuous Yielding

Low-carbon hot-rolled steel generally undergoes a deformation process composed of four phases, i.e., elastic deformation, discontinuous yielding, work hardening, and macroscopic plastic-strain localization in a tension test. The evolution of the Poisson’s ratio in terms of the average Poisson’s ratio and the local Poisson’s ratio in the deformation process from the non-load state to the onset point of specimen necking was investigated. The main results are as follows: (1) the average Poisson’s ratio cannot accurately represent the local Poisson’s ratio in the discontinuous-yielding phase; (2) the Poisson’s ratio varied significantly within a plastic band in the discontinuous-yielding phase, and the maximum Poisson’s ratio was reached within the plastic band; and (3) the strain rate greatly increased the Poisson’s ratio.

Using surround DIC to extract true stress–strain curve from uniaxial tension experiments

The exact stress–strain curve can be directly identified from uniaxial tension experiments up to the point of onset of diffuse necking. To gain insight into the post-necking hardening response of metals, other experimental methods such as the bulge, compression or torsion experiments are typically employed. Here, we introduce the idea of using surround DIC to obtain accurate specimen shape measurements of tensile specimens with rectangular gage section. Based on the results from a series of detailed three-dimensional finite element simulations of ASTM E8 type of uniaxial tension experiments on a wide spectrum of steel and aluminum behaviors, it is proposed to combine the history of the axial strain on the surface at the specimen center with the average axial stress to extract the stress–strain curve for strains of up to axial true strain of 1. The estimation uncertainty of this stress–strain curve estimation procedure is of the same order as that of the associated experimental uncertainties. This result is validated through an additional computational study for more than 100 distinct hardening behaviors. Furthermore, a surround DIC system composed of four stereo DIC systems is built and used to determine the stress–strain curve for a 1.5 mm thick DP780 steel. In addition, bulge experiments are performed on the same material revealing a good agreement of the post-necking hardening behavior determined through uniaxial and bulge testing.

Revisiting RANS prediction of transitional flow on T3A flat plate subject to various freestream turbulences

A laminar–turbulent transition subject to a freestream turbulence involves highly complex flow mechanisms, which have received considerable interest in the past decades. Accurately predicting such complex physical phenomena is significantly challenging using computational fluid dynamics solvers, particularly in industrial engineering applications. In this study, the capability of two transitional turbulence models—k−kl−ω and k−ω−γ−Re˜θt—to predict a T3A plate transition scenario was revisited. First, the predicted boundary layer data was compared to ERCOFTAC experimental measurements. Subsequently, a transitional flow subject to constant and sinusoidal freestream turbulences was systematically investigated. Under a constant freestream turbulence, the two models exhibited opposite tendencies of the transition starting and ending positions with the increase in Refst. However, there were still some similarities between the results of the two models. When the length scale was fixed, the transition area moved upstream with increasing turbulence intensity. The transition zone was more sensitive to a small length scale than to a considerable length scale. The dynamic boundary layer under the sinusoidal combination condition was less disturbed than the sinusoidal turbulence intensity and the sinusoidal specific turbulence dissipation rate. Regardless of the type of sinusoidal freestream turbulence the boundary layer was exposed to, increasing the oscillation frequency significantly disturbed the transitional flow. It was observed that the inertia effect of the dynamic onset point was enhanced by increasing the oscillation frequency. Concurrently, a significant phase delay occurred, and the delay time was approximately proportional to the oscillation frequency. The extreme position of the transition onset close to the leading edge of the plate was not affected by the oscillation frequency, whereas it depended on the sinusoidal variable. However, the extreme downstream transition onset point was significantly affected by the oscillation frequency.

Aldosterone activates cerebrovascular smooth muscle BK channels in absence of β1 subunits, yet these potentiate steroid action and thus facilitate aldosterone-induced dilation of cerebral arteries.

Calcium/voltage-gated, big conductance K+ channels (BK α subunits or slo1 proteins) modulate smooth muscle (SM) tone and thus cerebral artery diameter. In cerebral arteries, the BK current phenotype is conditioned by regulatory β1 subunits which fine-tune channel activity to tissue-specific physiology. Several physiological steroids modify BK function and may modify cerebral artery function. Thus, cholesterol and pregnenolone inhibit SM BK and evoke middle cerebral artery (MCA) constriction through recognition by slo1 whereas estradiol and cholanes activate SM BK through recognition by β1. Aldosterone is a steroid with documented vasoactive properties, yet the involvement of BK in aldosterone's cerebrovascular action and the contribution of distinct channel subunits to this action remain unknown. Here, we first used nanoscale differential scanning fluorimetry to test whether aldosterone (0.3-100 μM) could directly bind BK α or β1 subunits. Changes in temperature of onset and inflection point (indicators of protein-steroid binding) were evident at 10 and 1 µM aldosterone for α and β1. Next, MCA SM cells were enzymatically isolated from mice, and cell-free recordings were conducted to determine changes in BK activity by aldosterone. Increased activity by aldosterone was concentration-dependent: EC50 = 3 μM; ECMAX = 10 μM, at which activity increased by 20%. Consistently with this small yet reproducible SM BK activation, 10 μM aldosterone dilated MCA by 2%, independently of circulating and endothelial factors. In SM cells and MCA segments from β1-/- mice, aldosterone activated BK with reduced potency and efficacy, and vasodilation by the steroid was evoked by very high concentrations (>>10 µM). Therefore, aldosterone is able to activate SM BK in absence of β1, yet this regulatory subunit potentiates aldosterone action and thus enables subµM-µM aldosterone to dilate MCA.

A molecular dynamics approach to investigate effect of pressure on asphaltene self-aggregation

Asphaltene aggregation is a serious issue in the oil industry that negatively affects the production, transportation, and exploitation of oil, causing considerable costs. In the past few years, the experimental analysis of asphaltene aggregation has been a fascinating topic; however, a laboratory study that can assess the asphaltene aggregation behaviors at high pressures will be a costly and high-risk project. In this paper, molecular dynamics (MD) simulations are used to investigate the influence of pressure on the asphaltene aggregation phenomenon. The employed asphaltene in this research is Gachsaran asphaltene (obtained from an Iranian oilfield) with archipelago geometry. The aggregation number, radial distribution function (RDF), potential of mean force (PMF), cohesive energy, solubility parameter, mean square displacement (MSD), diffusion coefficient, relative concentration, potential energy, and radius of gyration are analyzed based on the data and results obtained from the output trajectory files. It is concluded that the number and the average size of asphaltene aggregates significantly decrease with increasing pressure because the pressure delays the growth of asphaltene aggregates by enhancing the asphaltene solubility parameter. The associated energies of asphaltene molecules at 35, 90, and 135 bar are calculated to be −15.7834, −15.7571, and −15.7249 kJ / mol, respectively. It is found that the tendency of asphaltene molecules to aggregate reduces upon an increase in pressure. Face-to-face interactions are more likely than T-shaped and offset stacking for this asphaltene sample because of the more aromatic nuclei in the asphaltene structure than the aliphatic chains, which increase the strength of the π-π interactions. It is also observed that by increasing pressure, the movement and vibration of asphaltene increase and then decrease by further increase in pressure. According to the asphaltene onset envelope diagram, the asphaltene molecules at 35 bar are located in the solid–liquid region. As the pressure increases to 90 bar, the asphaltene passes the upper asphaltene onset point zone. It can be concluded that when asphaltene is in the solid–liquid region, the mobility and displacement of molecules increase with increasing pressure. In the upper asphaltene onset point zone, the tendency of molecules to move is reduced. The MD results are consistent with the laboratory data.

Enhancing phenomenological yield functions with data: Challenges and opportunities

The formulation of history-dependent material laws has been a significant research and industrial activity in solid mechanics for over a century. A large variety of models has been developed, tailored for the description of different families of materials. However, model selection for a specific problem is a delicate issue and there still remain open problems. In fact, the catalog of yield models is continuously being enriched by experts to meet new needs and tailor models to new experimental evidence. We propose here an alternative approach, that is a flexible model-data-driven plasticity formulation, and analyze its challenges and opportunities. A phenomenological yield model is locally improved by a data-driven correction term. The data-based correction component is described by a surrogate model built from machine-learning techniques. In this regard, the framework is versatile, as shown by the fact that similar performances are obtained with Support Vector Regression, Gaussian Process Regression, and Neural Networks. The convexity of model-data yield functions is guaranteed by employing convex extensions of the adopted machine-learning techniques. The proposed approach is substantiated by reproducing a highly anisotropic yield response with tension/compression asymmetries from a simple phenomenological model enhanced with a limited number of synthetic data points of yield onset. It is shown that a crucial role is played by both model and data, the former allowing to use a limited number of data and the latter significantly enhancing model performance.

Therapeutic Trial of anle138b in Mouse Models of Genetic Prion Disease.

Phenotypic screening has yielded small-molecule inhibitors of prion replication that are effective in vivo against certain prion strains but not others. Here, we sought to test the small molecule anle138b in multiple mouse models of prion disease. In mice inoculated with the RML strain of prions, anle138b doubled survival and durably suppressed astrogliosis measured by live-animal bioluminescence imaging. In knock-in mouse models of the D178N and E200K mutations that cause genetic prion disease, however, we were unable to identify a clear, quantifiable disease endpoint against which to measure therapeutic efficacy. Among untreated animals, the mutations did not impact overall survival, and bioluminescence remained low out to >20 months of age. Vacuolization and PrP deposition were observed in some brain regions in a subset of mutant animals but appeared to be unable to carry the weight of a primary endpoint in a therapeutic study. We conclude that not all animal models of prion disease are suited to well-powered therapeutic efficacy studies, and care should be taken in choosing the models that will support drug development programs. IMPORTANCE There is an urgent need to develop drugs for prion disease, a currently untreatable neurodegenerative disease. In this effort, there is a debate over which animal models can best support a drug development program. While the study of prion disease benefits from excellent animal models because prions naturally afflict many different mammals, different models have different capabilities and limitations. Here, we conducted a therapeutic efficacy study of the drug candidate anle138b in mouse models with two of the most common mutations that cause genetic prion disease. In a more typical model where prions are injected directly into the brain, we found anle138b to be effective. In the genetic models, however, the animals never reached a clear, measurable point of disease onset. We conclude that not all prion disease animal models are ideally suited to drug efficacy studies, and well-defined, quantitative disease metrics should be a priority.

Variational autoencoder for prosody‐based speaker recognition

AbstractThis paper describes a novel end‐to‐end deep generative model‐based speaker recognition system using prosodic features. The usefulness of variational autoencoders (VAE) in learning the speaker‐specific prosody representations for the speaker recognition task is examined herein for the first time. The speech signal is first automatically segmented into syllable‐like units using vowel onset points (VOP) and energy valleys. Prosodic features, such as the dynamics of duration, energy, and fundamental frequency ( ), are then extracted at the syllable level and used to train/adapt a speaker‐dependent VAE from a universal VAE. The initial comparative studies on VAEs and traditional autoencoders (AE) suggest that the former can efficiently learn speaker representations. Investigations on the impact of gender information in speaker recognition also point out that gender‐dependent impostor banks lead to higher accuracies. Finally, the evaluation on the NIST SRE 2010 dataset demonstrates the usefulness of the proposed approach for speaker recognition.

The prevalence and clinical correlates of anxiety in Chinese patients with first-episode and drug-naïve major depressive disorder at different ages of onset

BackgroundMajor depressive disorder (MDD) with comorbid anxiety is very common and is associated with worse clinical outcomes. MDD patients at different ages of onset may have different clinical features and associated factors. The aim of this study was to investigate the prevalence of anxiety and related factors in MDD patients at different ages of onset. MethodsA total of 1718 first-episode and drug-naïve (FEDN) MDD patients were recruited. The cutoff point for early-adulthood onset (EAO) and mid-adulthood onset (MAO) was the first depressive episode before or after age 45 years. Clinical features (depressive, anxiety and psychiatric symptoms) and some metabolic parameters were collected. ResultsThere was no significant difference in the prevalence of anxiety between EAO patients (50.7 %) and MAO patients (55.7 %). For EAO patients, regression analysis showed that TSH levels, TgAb levels, and TC levels were significantly associated with anxiety. For MAO patients, regression analysis showed that anxiety was associated with HDL-c levels and impaired glucose metabolism. Furthermore, suicide attempts, psychotic symptoms, and depression severity were correlated with anxiety in both groups. LimitationsOur cross-sectional study cannot explain the causal relationship between anxiety and related factors in MDD patients at different ages of onset. ConclusionsThis study revealed that the clinical characteristics and factors associated with anxiety in MDD patients differed according to age of onset, and therefore age of onset needs to be considered while treating anxiety.

Estimation of neuronal task information in fMRI using zero frequency resonator

In functional magnetic resonance imaging (fMRI), temporal onsets of BOLD events contain crucial information on activity-inducing signals and make a significant impact in the analysis of functional connectivity (FC). In literature, the estimation of the onsets of the BOLD events from the acquired blood oxygen level-dependent (BOLD) signal using fMRI is mostly performed by choosing locations with a high value of the BOLD signal. This approach may give false onset points because it can incorporate redundant onsets which could be due to non-neuronal activity or can exclude true low-valued BOLD signals. In this study, we present a novel approach to estimating the temporal onsets of the BOLD events using a zero frequency resonator (ZFR) without necessitating information regarding the experimental paradigm (EP). The proposed approach exploits the impulse-like characteristic of activity-inducing signal to estimate the temporal onset points of BOLD events using ZFR which has been widely studied in the area of speech signal processing to estimate the glottal closure instances. The idea behind the approach is that an ideal neuronal impulse has, in principle, equal energy at all frequencies, including around the zero frequency, and will preserve the information of the temporal onsets of the BOLD events at its output. The ZFR-based approach estimates two important features, namely: 1) task-induced temporal onsets of the BOLD events in the fMRI time course and 2) high SNR (HSNR) regions around the estimated BOLD events. Both the estimated features are used to obtain the FC. Results are demonstrated using both the synthetic and experimental (event-related finger tapping and block design working memory) data. We show that a small number of plausible time points, estimated by ZFR, can convey sufficient information indicating the associated activation pattern. The method also illustrates its significance over the conventional correlation and threshold-based conditional rate analysis to estimate FC. The study demonstrates that ZFR-estimated BOLD events and HSNR regions can produce sufficient functionality of the brain in the task paradigm.

Addressing diffusion behavior and impact in an epoxy–amine cure system using molecular dynamics simulations

To deepen understanding of diffusion-controlled crosslinking, molecular dynamics (MD) simulations are carried out by taking the diffusion image of 3,3′-diamino diphenyl sulfone (3,3′-DDS) and polyethersulfone (PES) with epoxy resin varying temperatures from 393.15 to 473.15 K over crosslinking conversion of 0–85%. The diffusion of PES and 3,3′-DDS into the bulk increased with increasing the temperature as a result of enhanced mobility of the molecules when the difference between the glass-transition temperature (Tg) and the curing temperature. Beyond the onset points of the converged crosslinking conversion ratio of 3,3′-DDS and PES, their diffusion properties are obviously restricted with crosslinking conversion ratio. At low crosslinking conversion ratios (> 10%), the diffusion coefficients of triglycidyl p-aminophenol (TGAP) were 1.1 times higher than those of diglycidyl ether of bisphenol F (DGEBF) because of the lower molecular weight of TGAP. On the other hand, the diffusion coefficients of TGAP decreased when the crosslinking ratio was up to ~ 60% because, compared with DGEBF, it had more functional groups available to react with the curing agent. At higher crosslinking ratios, the diffusion coefficients of both resins converged to zero as a result of their highly crosslinked structures.

The influence of vegetable additives on the flocculation of asphaltenes in oil dispersed systems

The study examines the existing asphaltene flocculation inhibitors in oil dispersed systems — oil-soluble surfactants of various nature. It is proposed to use cheap surfactants of vegetable origin as flocculation inhibitors — phosphatide concentrate and sodium sulfosuccinate. The process of flocculation of asphaltenes on model mixtures of asphaltenes of different concentrations with toluene and precipitants, as well as the influence of the proposed inhibitors on the aggregative stability of the mixtures, was studied. The flocculation starting point (onset point) of each mixture was determined by the photocolorimetric method.

Can Biologics Be Discontinued in Patients with Psoriatic Arthritis in Stable Remission? A Prospective Single‐CenterClinical and Ultrasound Study

Biologic disease‐modifying antirheumatic drugs (bDMARDs) and particularly tumor necrosis factor inhibitors (TNFi) have dramatically changed the natural history of psoriatic arthritis (PsA), making complete clinical remission possible in most patients. However, TNFi drugs are not without potential adverse effects such as increased infectious risk. In addition, their extensive use is associated with a significant economic burden. This prospective longitudinal cohort study involving 45 PsA patients treated with TNFi in stable remission aimed to evaluate by both clinical examination and ultrasound timing and predictive factors of disease relapse after discontinuation of TNFi treatment. Thirty‐nine (86.6%) of 45 enrolled patients experienced disease relapse during the follow‐up period, while six patients (13.4%) maintained remission beyond the scheduled 104 weeks. The median survival time of drug‐free remission after TNFi discontinuation was 24 weeks (95% confidence interval (CI): 22.6–25.4). Disease relapse was characterized by marked clinical and ultrasound worsening of dermatologic and rheumatologic conditions. However, resuming previously discontinued treatment allowed all patients to quickly regain clinical remission. Interestingly, axial involvement was a key feature of the symptomatological pattern of disease relapse, being the main reason for treatment restart in 26% of our cohort. Based on a multivariate Cox model, three variables (VAS pain, tender joint count, and swollen joint count) of the clinical assessment performed at the time point of TNFi treatment onset negatively influenced the time to disease relapse. In conclusion, temporary discontinuation of TNFi drugs is feasible and relatively safe. However, as few predictors of the risk and timing of disease relapse have been identified, patients should be closely monitored when therapy is discontinued.