Reaction Time Variability Research Articles

A combined experimental-correlational approach to the construct validity of performance-based and self-report-based measures of sustained attention.

The ability to sustain attention is often measured with either objective performance indicators, like within-person RT variability, or subjective self-reports, like mind wandering propensity. A more construct valid approach, however, may be to assess the covariation in these performance and self-report measures, given that each of these is influenced by different sources of measurement error. If the correlation between performance-variability and self-report measures reflects the sustained attention construct, then task manipulations aimed at reducing the sustained attention demands of tasks should reduce the correlation between them (in addition to reducing mean levels of variability and mind wandering). The current study investigated this claim with a combined experimental-correlation approach. In two experiments (Ns ~ 1,500 each), participants completed tasks that either maximized or minimized the demand for sustained attention. Our demand manipulations successfully reduced the mean levels of sustained attention failures in both the objective and subjective measures, in both experiments. In neither experiment, however, did the covariation between these measures change as a function of the sustained attention demands of the tasks. We can therefore claim only minimal support for the construct validity of our measurement approach to sustained attention.

Mesoporous configuration effects on the physicochemical features of hierarchical ZSM-5 supported cobalt oxide as catalysts in methane partial oxidation

Hierarchical porous system has become a prevalent method to overcome the diffusion limitation of conventional zeolites. Two types of mesopores characterized as intra-crystalline (mesopores in the zeolite pore wall) and inter-crystalline mesopores (meso-sized voids between nano-zeolite aggregates) could be formed in the synthesis of hierarchical zeolites. In an attempt to investigate the influence of mesopores structure on the physicochemical properties of hierarchical ZSM-5, specifically cobalt oxide impregnated ZSM-5 zeolite samples with intra- and inter-crystalline mesopores were synthesized through two different synthesis strategies. Analysis of the physicochemical properties of the as-modified hierarchical ZSM-5 catalysts were carried out using SEM, TEM, XPS, and H2-TPR which showed distinct features given by the two mesopores configurations. Co-oxide impregnated on ZSM-5 with inter-crystalline mesopores was dominated by Co(II) species, while Co-oxide/ZSM-5 showed a fair amount of Co(III) and Co(II). Furthermore, analysis of the catalytic activity was conducted using methane partial oxidation as a model reaction. With a variation in reaction time, various types of oxygenated products, i.e. methanol, formaldehyde, formic acid, and a small trace of carbon dioxide were observed. Catalytic results suggested that the Co-oxide/ZSM-5 material with inter-crystalline mesopores configuration is more active for the methane partial oxidation reaction compared to the Co-oxide/ZSM-5 with intracrystalline mesopores. This was confirmed by the formation of formaldehyde rather than methanol as the major product in the brief reaction time of 30 min.

Modulating the magnetic anisotropy in SmCo/Co nanocomposites through alteration in spin–orbit coupling

In the present work, one-dimensional (1-D) as-synthesized SmCo/Co magnetic nanocomposites were prepared through magnetically-assisted chemical reduction method. The samples were prepared with the varying reaction times between 1 and 10 h labelled as SC1, SC2, SC5, SC7 and SC10. The Rietveld refinement of XRD patterns revealed the presence of Sm(OH)3 (P63/m), hcp-Co (P63/mmc), cubic-Co (Fm-3 m) and Sm2Co17 (P63/mmc) phases with varying phase fractions. The nanocomposites were found to possess the highest aspect ratio (∼7) with lowest crystallite size (∼50 nm) along with the highest developed lattice strain in SC5. The decisive influence of the reaction time was observed on the magnetic response of the samples indicating highest saturation magnetization of ∼ 150 emu/g and effective magnetic anisotropy of ∼ 1.5 x 106 erg/cm3 in SC5. The generalized form of Bloch law was employed to study the origin of magnetic anisotropy determined as spin–orbit coupling which was found to be highest in SC5. It was suggested that the enhanced magnetic properties of the nanocomposites are attributable to the high fraction of magnetic phases with the soft magnetic character and coupling between multiple phases.

Childhood trauma, intraindividual reaction time variability, baseline respiratory sinus arrhythmia, and perceived relapse tendency among males with substance use disorders

ABSTRACTBackground: People with substance use disorders (SUDs) who have experienced serious childhood trauma may have executive function impairments contributing to relapse. Baseline respiratory sinus arrhythmia (RSA) reflects physiological regulation capacity, which has been found to buffer the negative effects of childhood trauma. Baseline RSA has also been found to be related to intraindividual reaction time variability (IIRTV), which is an index of executive function.Objectives: The present study examined the relationship between childhood trauma and perceived relapse tendency, the mediation role of IIRTV, and the moderation role of baseline RSA.Methods: The study is cross-sectional, a total of 110 males with SUDs participated (Mage = 46.45 years, SD = 11.24). The Childhood Trauma Questionnaire and Intention to Rehabilitate Questionnaire were used to assess childhood trauma and perceived relapse tendency, the two-choice oddball task was used to measure IIRTV, and electrocardiogram (ECG) data were collected to obtain baseline RSA.Results: IIRTV mediated the relationship between childhood trauma and perceived relapse tendency (Coeff = 0.049, Boot CI [0.004, 0.121]); interaction of childhood trauma and Baseline RSA negatively influences IIRTV (β = –0.208, t = –2.022, p = .046).Conclusion: The results suggest that males with SUDs who have experienced serious childhood trauma may have executive function impairments that contribute to relapse, and baseline RSA may buffer the negative effect of childhood trauma on IIRTV. These findings suggest that the prevention of relapse through cognitive enhancement can be complemented by the enhancement of physiological regulation.

Synthesis of AgFeO2 delafossite catalyst and its application for photo-degradation of dye present in solution

The present work highlights the physicochemical properties of a series of novel silver ferric oxide (AgFeO2) delafossite nanoparticles while employing them as photocatalysts under visible light irradiation. The first sample was synthesized by a facile co-precipitation route (AFO-0) while the second and third samples were prepared at a constant hydrothermal temperature (180 °C) with varying reaction time of 2 h (AFO-2) and 8 h (AFO-8) and all three samples were subjected to visible light irradiation to photo-degrade Malachite Green (MG) dye. The crystalline structure, morphology, functional groups, elemental analysis, and optical property was conducted by their respective characterization techniques. The size of nanocrystals increased with the hydrothermal time and the average particle size of AFO-0, AFO-2 and AFO-8 were 87.7 nm, 154 nm, and 209.3 nm respectively, with AFO-8 exhibiting prominent hexagonal flake-like morphology. The direct band gap of AFO-0, AFO-2 and AFO-8 were 2.74 eV, 2.53 eV and 2.11 eV respectively and the Urbach energy was 0.20 eV, 0.217 eV and 0.254 eV respectively. The photo generated charge isolation efficiency of the samples was conducted where charge recombination sequence was of the order: AFO-8<AFO-2<AFO-0. The sample AFO-8 exhibited the optimum performance which resulted in excellent degradation of MG under visible light irradiation based on all the batch study experiments using solution pH, comparative analysis, catalyst dose, initial pollutant concentration as parameters. Finally, the optimum conditions at which AFO-8 degraded 97 % of MG were: 80 mg catalyst dose, pH 8, 20 mg L−1 (100 mL) MG, 90 min reaction time, 30 °C temperature and 130 rpm agitation speed. As per the quenching tests, the OH° and O2°− radicals were the governing reactive species that were responsible for degrading MG.

17 Norming for the reverse-translated 5-choice continuous performance test (5C-CPT) of attention and cognitive control

Objective:Translatability of preclinical results remains a major obstacle in neuropsychiatric research. Even when cognitive tests in preclinical models show translational validity for human testing, with sensitivity to clinical deficits, there remains the issue of heterogeneity among human participants. Norming of performance on cognitive tasks enable corrections for any differences in performance that may arise from the influence of socioeconomic factors, and thus a more direct comparison with preclinical testing results. The 5-choice continuous performance task (5C-CPT) is a test sensitive to changes in sustained attention and cognitive control in rodent manipulations and clinical populations, including schizophrenia and bipolar disorder. Herein, we present normed results of 5C-CPT data from a cohort of human participants, enabling greater comparison to future clinical and rodent testing.Participants and Methods:5C-CPT data were generated from a range of participants from the Translational Methamphetamine AIDS Research Center (n=82) and a study of bipolar disorder (n=45). Participant demographics were as follows: Age M=38.5, SD=16.7, Education: M=14.5, SD=1.9, 45% female, 10% Asian, 17% African American, 27% Hispanic, and 46% non-Hispanic White. We used the test2norm R-package to create norms for each of the major outcomes from the 5C-CPT. Non-normally distributed raw scores were transformed to generate more normally distributed data needed for the norming process. Raw scores were first converted into uniform scaled scores that range from 0-20 where a higher score indicated better performance. We then generated T-score formulas, which are standardized residuals and scaled to have a mean of 50 and standard deviation of 10. The residuals are obtained from regressions, modeled using multiple fractional polynomial method (MFP), which regresses scaled scores on demographic variables, which a user wishes to control for (gender, age, education, ethnicity, etc.). MFP models allow to fit non-linear effects for numeric demographic factors (e.g., age), if such effects exist.Results:New, demographically corrected T-score formulas were calculated for each major outcome of the 5C-CPT: reaction time (MCL), reaction time variability (VarRT), dprime, hit rate (HR) and false-alarm rate (FAR). MFP models showed that age had a significant effect on MCL, VarRT, dprime, and HR (all p&lt;0.01), while gender only showed a significant effect for MCL and VarRT (all p&lt;0.05). Interestingly, education and ethnicity did not show a significant effect for any MFP model and none of the demographic factors (age, education, gender, ethnicity) were significant in the model for FAR. As defined in the test2norm package, all scaled scores had a mean of 10 and SD of 3 and all T-scores had a mean of 50 and SD of 10.Conclusions:The 5C-CPT is a test of attention and cognitive control available for human testing, reverse-translated from rodent studies. The normative data generated here will enable future comparisons of data without the need for additional control studies. Furthermore, comparing these normative data to manipulations will enable further comparisons to rodent testing, with manipulations relative to baseline becoming more meaningful. Thus, the 5C-CPT is a viable tool for conducting cross-species translational research toward developing novel therapeutics that treat dysfunctional attentional and cognitive control.

24 Mindfulness-based cognitive therapy enhances executive control in recurrent depression in a randomized wait-list controlled trial

Objective:Adults with recurrent depression have been shown to have cognitive deficits also while in remission. Thus, it has been suggested that with a chronic course of depression, poorer executive control can be a vulnerability factor for depressive relapse. This has led to research on how cognitive remediation training can protect against recurrent depressive episodes. Findings indicate that such training has short term effects on cognitive functioning, and small effect on depression symptoms. Less focus has been on how “standard” psychotherapy can have positive effects on executive and attentional control. Mindfulness-based cognitive therapy (MBCT) has been shown to be as effective as antidepressant medication in preventing relapses of depressive episodes. Mindfulness training in healthy samples seems to improve executive and attentional control. However, the few studies of MBCT in recurrent depression show mixed effects on executive and attentional control. As far as we know, no prior study has investigated the effect of MBCT in recurrent depression with the revised version of the attention network test (ANT-R). In a randomized controlled trial, we expected that the MBCT group would show enhanced executive control and lower levels of attentional fluctuations than the wait-list controls (WLC) from pre (T0) to post (T1) treatment. We further investigated if positive effects of MBCT on executive and attentional control were associated with reduction in depression symptoms.Participants and Methods:Adults with recurrent depression in partial or full remission (N = 64) were randomized to MBCT or WLC. In the MBCT and WLC groups, 25 and 29, respectively, performed the ANT-R at T0 and T1. The attention network reaction time scores of executive control, alerting, and orienting were calculated in addition to attention fluctuations scores of intra-individual reaction time variability (IIVRT) and exgaussian-mean of longer reaction times (TAU). Self-reported depression symptoms were measured with BDI-II. The two groups were compared at baseline on full-scale IQ (WASI), executive control (D-KEFS Stroop), and processing speed (D-KEFS TMT).Results:The MBCT and WCL groups did not differ significantly in age or gender distribution, education, full-scale IQ or in baseline executive and attentional control as measured with the ANT-R, Stroop and TMT. The MBCT group showed a higher efficiency in conflict detection as measured with the executive control score from T0 to T1 compared to the WLC. This positive effect of MBCT on executive control was independent from the greater reductions in depression symptoms in the MBCT group compared to in the WLCs. However, reduction in depression symptoms at T1 was associated with enhanced efficiency in responding to alerting cues in conflict detection. No effects of MBCT compared to WLC were found at T1 on the attention fluctuation measures (IIVRT and TAU).Conclusions:The findings from the current study indicates that MBCT enhances executive control in adults with recurrent depression. As such, MBCT may target an important cognitive vulnerability factor in the chronic course of recurrent depression that may contribute to its efficacy in preventing depressive relapses. It was also observed that reductions in depression symptoms led to higher alertness in conflict detection.

Effects of stochastic vestibular stimulation on cognitive performance in children with ADHD

Previous work has shown that exposure to auditory white noise (WN) can improve cognitive performance in children with ADHD, but it is unknown whether this improvement generalizes to other sensory modalities. To address this knowledge gap, we tested the effect of Stochastic Vestibular Stimulation (SVS) on cognitive performance and reaction time (RT) variability in two groups: children with ADHD and typically developing children (TDC). Children with ADHD (N=42) and TDC (N=28) performed three cognitive tasks (Spanboard, Word Recall and N-back tasks) at two different occasions, with and without exposure to SVS, in a double blinded design. The results showed no main effects of SVS on neither performance nor RT variability for children in any of the groups, and no interactions between SVS and group. Based on these results we conclude that, using our stimulation protocol, the positive effects of WN exposure on cognition in children with ADHD do not generalize to Stochastic Vestibular Stimulation.

Resting-state EEG dynamics help explain differences in response control in ADHD: Insight into electrophysiological mechanisms and sex differences.

Reductions in response control (greater reaction time variability and commission error rate) are consistently observed in those diagnosed with attention-deficit/hyperactivity disorder (ADHD). Previous research suggests these reductions arise from a dysregulation of large-scale cortical networks. Here, we extended our understanding of this cortical-network/response-control pathway important to the neurobiology of ADHD. First, we assessed how dynamic changes in three resting-state EEG network properties thought to be relevant to ADHD (phase-synchronization, modularity, oscillatory power) related with response control during a simple perceptual decision-making task in 112 children/adolescents (aged 8-16) with and without ADHD. Second, we tested whether these associations differed in males and females who were matched in age, ADHD-status and ADHD- subtype. We found that changes in oscillatory power (as opposed to phase-synchrony and modularity) are most related with response control, and that this relationship is stronger in ADHD compared to controls. Specifically, a tendency to dwell in an electrophysiological state characterized by high alpha/beta power (8-12/13-30Hz) and low delta/theta power (1-3/4-7Hz) supported response control, particularly in those with ADHD. Time in this state might reflect an increased initiation of alpha-suppression mechanisms, recruited by those with ADHD to suppress processing unfavourable to response control. We also found marginally significant evidence that this relationship is stronger in males compared to females, suggesting a distinct etiology for response control in the female presentation of ADHD.

An electrochemical sensor made with thermally regulated sheets of Ce2(WO4)3@rGO nanocomposite for aqueous hydroquinone detection

Hydroquinone (HQ) is a toxic and poorly biodegradable substance that can cause various health issues. To address this problem, we devised an electrochemical sensor using Ce2(WO4)3@rGO (CeW@rGO) nanocomposites coated onto a glassy carbon electrode (GCE). The novel nanocomposites were synthesized using a hydrothermal process, with varying reaction times of 2, 6, 12, 24, and 48 h. It was then treated with a surfactant and combined with reduced graphene oxide (rGO) to produce CeW@rGO nanocomposite. The GCE was then modified using different CeW-X (where X represents the reaction times of 2, 6, 12, 24, and 48 h). Among these, the CeW-6@rGO nanocomposite exhibited the most optimal electrochemical behavior. Our results showed that the novel sensor made with CeW-6@rGO nanocomposites possesses long-term stability with high selectivity for sensing HQ. The new CeW-6@rGO/GCE sensor has a detection limit of 0.00964 μM with a linear range of 0.1–115 µM and can detect HQ in real-world water samples with reliable results. Our findings suggest that this novel sensor is potentially useful in real-world applications.

Interoception in the Determination of Reaction Times and Pulse Amplitude Sensitivity

Interoception is the awareness of changes of sensation within the body. Over the years, interoception has been analyzed in the context of the perception of visceral activity and its effects on emotional regulation. There is little to no knowledge of how the interoceptive ability of an individual affects physical parameters such as Reaction Time (RT). Measures such as the MAIA-2 have been used to rank an individual’s interoceptive ability. The Multidimensional Assessment of Interoceptive Awareness (MAIA) is an 8-scale state-trait questionnaire with 37 items to measure multiple dimensions of interoception by self-report. Participants (n = 29, x̄ = 21.4 years) in the study first completed the MAIA-2 and a series of tests to extrapolate measures of RT [ms], Reaction Time Variability (RTV) [ms], and the minimum differentiable pulse amplitude (lower limen) [um] of two stimuli. RT and RTV scores were compared to subscales scores of Noticing, Self-regulation, and Body-Listening. Non-Distracting, Non-Worrying, and Attention Regulation were compared to lower limen scores. External cues for these measures were presented with the Brain Gauge from Cortical Metrics. No correlations were found between the RT, RTV, lower limen, and their respective MAIA-2 categories. Clusters of data are evident for certain categories (i.e. RTV), however, they may be influenced by the age composition of the sample. Though there are no conclusive results, further post-testing along with more variable samples could reveal connections between self-perception and interactions with the environment.

Effects of Genre, Emotional Response, and Perception of Music on Simple Cognitive Tasks

Investigating the impact of music on cognitive performance is incredibly complex, in part because of the potential for wide variation in the qualities of the music and the type and complexity of the cognitive task being performed. This study examined how variations in genre, familiarity, and enjoyment of background music affected the performance of 41 individuals on somatosensory simple and choice reaction tests. Although no significant trends were found in parameters of reaction time, reaction time variability, choice reaction time, and percent of correct choices on choice reaction time, trends in the data suggest that further investigation into the effects of familiarity, enjoyment, and other such emotional components of music processing on cognitive performance may be a valuable direction for more extensive testing.

The Effects of Quiet Eye Training on Attention in Children with ADHD.

Based on linkage between attention control, gaze and visuomotor control, previous studies suggested that quiet eye training (QET) could improve attention control. The aim of the study was to investigate the effects of QET-based visuomotor intervention on different aspects of attention in children with ADHD. Fifty seven children with ADHD aged 9-12 years, were tested on focused, tonic and phasic attention, as well as attention control during a throwing task analysed via eye tracking, in pre- and post-test sessions, six weeks apart. The QET group that underwent specific 5-week QET-based intervention significantly increased focused attention including its accuracy aspect. Reaction times (RTs) and intraindividual RT variability under non-alert and alert conditions as measures of tonic and phasic attention did not change over time in either group. In contrast with the control (CON) group, an extended total time of eye fixations during the pre-throw and throw phase was found in the QET group after the intervention. The results of this study suggest that focused attention in children with ADHD can be improved by a short-term QET-based visuomotor intervention. Future research needs to examine the effects of a longer QET-based intervention, or the intervention in combination with other cognitive training of attention.

Microencapsulated epoxidized palm oil: A self-healing coating solution

Coatings are susceptible to cracking due to chemical exposure and mechanical forces. To enhance their durability and self-healing properties, microcapsules are utilized. In this study, poly(urea formaldehyde) microcapsules containing epoxidized palm oil as the core material were synthesized and investigated for their self-healing properties in diglycidyl ether of bisphenol A (DGEBA) epoxy resin. The epoxidation reaction of palm oil was carried out by varying reaction times and the molar ratio of hydrogen peroxide to formic acid to achieve an effective oxygen carrier with a high oxirane oxygen content. The formation of epoxide groups was confirmed using Fourier transform infrared spectroscopy (FT-IR) and Fourier transform Nuclear Magnetic Resonance Spectroscopy (NMR). The core-shell structure of the microcapsules was characterized using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Pencil hardness and adhesion tests were conducted on the epoxy coatings containing different amounts of microcapsules to evaluate the impact of microcapsules on hardness and adhesion properties. The epoxy coatings with microcapsules demonstrated significant self-healing ability and provided effective anti-corrosive protection. Higher microcapsule contents resulted in improved self-healing performance. Furthermore, the addition of microcapsules at 5 to 15 wt % did not compromise the hardness and adhesion properties of the epoxy coating.

Depression, anxiety and problematic smartphone use: the moderating roles of inhibitory control and trial-to-trial intraindividual reaction time variability

Depression, anxiety and problematic smartphone use: the moderating roles of inhibitory control and trial-to-trial intraindividual reaction time variability

Executive Control and Associated Brain Activity in Children With Familial High-Risk of Schizophrenia or Bipolar Disorder: A Danish Register-based Study.

Impaired executive control is a potential prognostic and endophenotypic marker of schizophrenia (SZ) and bipolar disorder (BP). Assessing children with familial high-risk (FHR) of SZ or BP enables characterization of early risk markers and we hypothesize that they express impaired executive control as well as aberrant brain activation compared to population-based control (PBC) children. Using a flanker task, we examined executive control together with functional magnetic resonance imaging (fMRI) in 11- to 12-year-old children with FHR of SZ (FHR-SZ) or FHR of BP (FHR-BP) and PBC children as part of a register-based, prospective cohort-study; The Danish High Risk and Resilience study-VIA 11. We included 85 (44% female) FHR-SZ, 63 (52% female) FHR-BP and 98 (50% female) PBC in the analyses. Executive control effects, caused by the spatial visuomotor conflict, showed no differences between groups. Bayesian ANOVA of reaction time (RT) variability, quantified by the coefficient of variation (CVRT), revealed a group effect with similarly higher CVRT in FHR-BP and FHR-SZ compared to PBC (BF10 = 6.82). The fMRI analyses revealed no evidence for between-group differences in task-related brain activation. Post hoc analyses excluding children with psychiatric illness yielded same results. FHR-SZ and FHR-BP at age 11-12 show intact ability to resolve a spatial visuomotor conflict and neural efficacy. The increased variability in RT may reflect difficulties in maintaining sustained attention. Since variability in RT was independent of existing psychiatric illness, it may reflect a potential endophenotypic marker of risk.

Delayed and More Variable Unimanual and Bimanual Finger Tapping in Alzheimer's Disease: Associations with Biomarkers and Applications for Classification.

Despite reports of gross motor problems in mild cognitive impairment (MCI) and Alzheimer's disease (AD), fine motor function has been relatively understudied. We examined if finger tapping is affected in AD, related to AD biomarkers, and able to classify MCI or AD. Forty-seven cognitively normal, 27 amnestic MCI, and 26 AD subjects completed unimanual and bimanual computerized tapping tests. We tested 1) group differences in tapping with permutation models; 2) associations between tapping and biomarkers (PET amyloid-β, hippocampal volume, and APOEɛ4 alleles) with linear regression; and 3) the predictive value of tapping for group classification using machine learning. AD subjects had slower reaction time and larger speed variability than controls during all tapping conditions, except for dual tapping. MCI subjects performed worse than controls on reaction time and speed variability for dual and non-dominant hand tapping. Tapping speed and variability were related to hippocampal volume, but not to amyloid-β deposition or APOEɛ4 alleles. Random forest classification (overall accuracy = 70%) discriminated control and AD subjects, but poorly discriminated MCI from controls or AD. MCI and AD are linked to more variable finger tapping with slower reaction time. Associations between finger tapping and hippocampal volume, but not amyloidosis, suggest that tapping deficits are related to neuropathology that presents later during the disease. Considering that tapping performance is able to differentiate between control and AD subjects, it can offer a cost-efficient tool for augmenting existing AD biomarkers.

An aldehyde as a rapid source of secondary aerosol precursors: theoretical and experimental study of hexanal autoxidation

Abstract. Aldehydes are common constituents of natural and polluted atmospheres, and their gas-phase oxidation has recently been reported to yield highly oxygenated organic molecules (HOMs) that are key players in the formation of atmospheric aerosol. However, insights into the molecular-level mechanism of this oxidation reaction have been scarce. While OH initiated oxidation of small aldehydes, with two to five carbon atoms, under high-NOx conditions generally leads to fragmentation products, longer-chain aldehydes involving an initial non-aldehydic hydrogen abstraction can be a path to molecular functionalization and growth. In this work, we conduct a joint theoretical–experimental analysis of the autoxidation chain reaction of a common aldehyde, hexanal. We computationally study the initial steps of OH oxidation at the RHF-RCCSD(T)-F12a/VDZ-F12//ωB97X-D/aug-cc-pVTZ level and show that both aldehydic (on C1) and non-aldehydic (on C4) H-abstraction channels contribute to HOMs via autoxidation. The oxidation products predominantly form through the H abstraction from C1 and C4, followed by fast unimolecular 1,6 H-shifts with rate coefficients of 1.7×10-1 and 8.6×10-1 s−1, respectively. Experimental flow reactor measurements at variable reaction times show that hexanal oxidation products including HOM monomers up to C6H11O7 and accretion products C12H22O9−10 form within 3 s reaction time. Kinetic modeling simulations including atmospherically relevant precursor concentrations agree with the experimental results and the expected timescales. Finally, we estimate the hexanal HOM yields up to seven O atoms with mechanistic details through both C1 and C4 channels.

The effects of reaction time on kinematic viscosity and conversion in the manufacturing of bio-ubricant alternatives from oleic acid with palm kernel shell catalyst as an approach to renewable energy

The effects of reaction time on kinematic viscosity and conversion in the manufacturing of bio-ubricant alternatives from oleic acid with palm kernel shell catalyst as an approach to renewable energy

Flower-like In2O3-ZnO nanosensor with improved acetone performance at low temperature

In2O3-ZnO nanoflower-like acetone gas sensors with varied reaction time were created using a simple and green synthesis idea. Morphological and structural analysis indicated that the In2O3-ZnO nanoflowers were made up of nanoplates with a thickness of around 35–60 nm and some small nanoparticles with the particle size of about 11 nm adhered to the surface. With a sensitivity of 238 for 100 ppm acetone at 140 °C, a lower detection limit as low as 0.64 ppm, good selectivity and excellent stability, the In-Zn(5) sensor with a hydrothermal time of 5 h has the most excellent performance. The enhanced gas-sensitive performance of In-Zn(5) can be attributed to the heterogeneous structure between the two and the three-dimensional flower-like structure with a large specific surface area and fast gas transfer rate. This work brings a better prospect for the future detection of acetone.