Significant Reduction In Reaction Time Research Articles

Эффект переноса имплицитного знания на сенсомоторную деятельность

The article is addressed on research aimed to discover effect of transfer of implicit knowledge of artificial grammar on sensorimotor tasks solving. Meaning of implicit knowledge in actual cognitive activity has been considered. 40 volunteers took part in experiment, ages 18 to 43 years. Participants of experiment implicit learned the rule of artificial grammar. The task of control phase was to solve the sensorimotor task — to react by pressing of certain key under appearance of green or yellow circle. In experimental group, always before presentation of green circle a grammatical sequence appeared, before presentation of yellow circle — ungrammatical. In control group, color of circle was not dependent on grammatically of sequence. The results have shown that significant reduction of reaction time was discovered in experimental group. Thus, transfer of implicitly learned knowledge of artificial grammar leads to increase of effectiveness of sensorimotor activity. Implicit knowledge acquired meaning prim-stimulation.

Spatial Attention in Binge-Drinking and Moderate-Drinking College Students: An fMRI Investigation

ABSTRACTCollege-age binge drinking is considered a developmental disturbance that may give rise to unique treatment challenges. The present study used functional magnetic resonance imaging (fMRI) during the completion of a spatial Stroop task to compare brain activation of 24 college-aged participants: 12 moderate drinkers (MoD) and 12 binge drinkers (BD). Overall, the BD showed a significant reduction in reaction time and accuracy in performing this task, while concurrently displaying less overall brain activation than moderate-drinking controls. In general, the BD showed decreased activity in regions related to rule discovery but hyperactivation in areas thought to mediate attention and response inhibition. Implications for treatment are discussed.

Preparation of Highly Pure n‐3 PUFA‐Enriched Triacylglycerols by Two‐Step Enzymatic Reactions Combined with Molecular Distillation

AbstractHighly pure n‐3 polyunsaturated fatty acids (PUFA)‐enriched triacylglycerols (TAG) have attracted considerable attention due to their nutritional benefits and pharmacological effects. In this study, an alternative approach to the conventional method for the synthesis of highly pure n‐3 PUFA‐enriched TAG by using a multi‐step process was reported. First, glyceride mixtures were synthesized through Novozym 435 [Novozymes A/S (Bagsvaerd, Denmark)] catalyzed esterification of n‐3 PUFA‐enriched FA and glycerol. Second, partial glycerides in the resulting glyceride mixtures were hydrolyzed to FA by immobilized partial glycerides‐selective lipase from Malassezia globosa. The purity of TAG reached 99.84% under the optimized conditions: buffer solution of pH 6.0, water content of 100% (w/w, with respect to the oil mass), enzyme loading of 120 U/g (U/w, with respect to oil mass) and reaction temperature of 30 °C. During hydrolysis, the immobilized SMG1‐F278N exhibited good reusability and TAG purity of over 94% was maintained after being used for six cycles. Subsequently, purification of TAG was accomplished by molecular distillation at low temperature (150 °C) and highly pure (99.85%) TAG with 88.73% n‐3 PUFA was obtained. The final glyceride mixtures with low acid, peroxide and anisidine value were promising products for medical and dietetic purposes. Compared with the conventional one‐step synthesis of n‐3 PUFA‐enriched TAG by enzymatic esterification or glycerolysis or the two‐step method by combined transesterification and ethanolysis, this improved process allows for higher purity of n‐3 PUFA‐enriched TAG and significant reduction in reaction time.

Proppant immobilization facilitated by carbon nanotube mediated microwave treatment of polymer-proppant structures

The application of multi-walled carbon nanotubes (MWCNTs) to facilitate the aggregation of ceramic particles (proppants) by embedding in the coating through localized microwave heating is reported. Thermogravimetric analysis (TGA), scanning electron microscopy (SEM) along with energy dispersive X-ray analysis (EDX) and atomic force microscopy (AFM) were used to characterize a series of covalently functionalized proppants with carboxylic acids (lysine and fumaric acid). The bi-functional acids allow for a controlled reaction with a coating (resin and polymer). The addition of carbon nanotubes results in the melting of the coating under exposure to microwave irradiation (20s @ 100W) joining the particles. The significant reduction in reaction time (compared to the thermal treatments of 2–24h) is due to the presence of the MWCNTs. The microwave heating of the MWCNTs can thus be used to create interaction and adhesion between functionalized particles subject to a specific stimulus.

Ultrasonic and microwave effects on crystalline Mn(II) carbonate catalyzed biodiesel production using watermelon (Citrullus vulgaris) seed oil and alcohol (fibrous flesh) as exclusive green feedstock

ABSTRACTUltrasonic sonication and microwave irradiation exhibited pronounced effects on crystalline Mn(II) carbonate catalyzed biodiesel production using watermelon (Citrullus vulgaris) seed oil and alcohol (fibrous flesh) as exclusive green feedstock. Both ingredients, alcohol and oil, necessary for biodiesel production are extracted from watermelon fruit. Mn(II) carbonate and watermelon fruit, which are used for transesterification, are inexpensive, easily available and environmentally safe. The reactions occurred smoothly under conventional conditions and afforded good product yields. However, microwave assisted and ultrasonically assisted reactions exhibited highly significant reduction in reaction times with a trend: microwave assisted (35 min) << ultrasonically assisted (2.0 h) << conventional (8.0 h). The whole exercise is operationally simple, environmentally safe, energy saving, time saving and green, which fits well into the green chemical principles of Anastas and Warner.

Oxytocin to modulate emotional processing in schizophrenia: A randomized, double-blind, cross-over clinical trial

Deficits in social cognition, including emotional processing, are hallmarks of schizophrenia and antipsychotic agents seem to be ineffectual to improve these symptoms. However, oxytocin does seem to have beneficial effects on social cognition. The aim of this study was to examine the effects of four months of treatment with intranasal oxytocin, in 31 patients with schizophrenia, on distinct aspects of social cognition. This was assessed using standardized and experimental tests in a randomized, double-blind, placebo-controlled, cross-over trial. All patients underwent clinical and experimental assessment before treatment, four months after treatment and at the end of treatment. Social cognition abilities were assessed with the Mayer–Salovey–Caruso Emotional Intelligence Test (MSCEIT) and the Reading the Mind in the Eyes task (RMET). Furthermore, an Emotional Priming Paradigm (EPP) was developed to examine the effects of oxytocin on implicit perceptual sensitivity to affective information and explicit facial affect recognition.We found that oxytocin improved performance on MSCEIT compared to placebo in Branch 3-Understanding Emotion (p-value=0.004; Cohen׳s d=1.12). In the EPP task, we observed a significant reduction of reaction times for facial affect recognition (p-value=0.021; Cohen׳s d=0.88). No effects were found for implicit priming or for theory of mind abilities. Further study is required in order to highlight the potential for possible integration of oxytocin with antipsychotic agents as well as to evaluate psycho-social treatment as a multi-dimensional approach to increase explicit emotional processing abilities and compensate social cognition deficits related to schizophrenia.

Startle reveals decreased response preparatory activation during a stop-signal task.

In a stop-signal task participants are instructed to initiate a movement in response to a go signal, but to inhibit this movement if an infrequent stop signal is presented after the go. Reaction time (RT) in a stop-signal task is typically longer compared with that in a simple RT task, which may be attributed to a reduced readiness to initiate the response caused by the possibility of having to inhibit the response. The purpose of this experiment was to probe the preparatory activation level of the motor response during a stop-signal task using a startling acoustic stimulus (SAS), which has been shown to involuntarily trigger sufficiently prepared responses at a short latency. Participants completed two separate tasks: a simple RT task, followed by a stop-signal RT task. During both tasks, an SAS (120 dB) was pseudorandomly presented concurrently with the go signal. As expected, RT during the simple RT task was significantly shorter than during the stop-signal task. A significant reduction in RT was noted when an SAS was presented during the simple RT task; however, during the stop-signal task, an SAS resulted in either a significant speeding or a moderate delay in RT. Additionally, the subset of SAS trial responses with the shortest RT latencies produced during the stop-signal task were also delayed compared with the short-latency SAS trial responses observed during the simple RT task. Despite evidence that a response was prepared in advance of the go signal during a stop-signal task, it appears that the amount of preparatory activation was reduced compared with that achieved during a simple RT task.

Iron(III) Fluorinated Porphyrins: Greener Chemistry from Synthesis to Oxidative Catalysis Reactions.

Iron(III) fluorinated porphyrins play a central role in the biomimetics of heme enzymes and enable cleaner routes to the oxidation of organic compounds. The present work reports significant improvements in the eco-compatibility of the synthesis of 5,10,15,20-tetrakis-pentafluorophenylporphyrin (H2TPFPP) and the corresponding iron complex [Fe(TPFPP)Cl], and the use of [Fe(TPFPP)Cl] as an oxidation catalyst in green conditions. The preparations of H2TPFPP and [Fe(TPFPP)Cl] typically use toxic solvents and can be made significantly greener and simpler using microwave heating and optimization of the reaction conditions. In the optimized procedure it was possible to eliminate nitrobenzene from the porphyrin synthesis and replace DMF by acetonitrile in the metalation reaction, concomitant with a significant reduction of reaction time and simplification of the purification procedure. The Fe(III)porphyrin is then tested as catalyst in the selective oxidation of aromatics at room temperature using a green oxidant (hydrogen peroxide) and green solvent (ethanol). Efficient epoxidation of indene and selective oxidation of 3,5-dimethylphenol and naphthalene to the corresponding quinones is observed.

Monolaurin yield optimization in selective esterification of glycerol with lauric acid over post impregnated HPW/SBA-15 catalyst

Process optimization of selective esterification of glycerol with lauric acid catalyzed by highly uniformed SBA-15 catalysts post impregnated with 12-tungstophosphorus acid (HPW) has been elucidated via response surface methodology (RSM). The significance of factors including reaction time (t), reactants ratio (R) and temperature (T) was investigated and led to the development of response models for lauric acid conversion (R1) and monolaurin yield (R2). The optimized monolaurin yield operating condition (50% yield at t=3.18 h, R=4.6 and T=175 °C) was identified by using the developed models with high accuracy (98% confidence level, small standard deviation and error) and reproducibility (3 times). Comparison done with reported results showed the good performance of developed catalyst with significant reduction in reaction time needed to achieve similar lauric acid conversion and monolaurin yield.

Precision Synthesis of a Long-Chain Silane Coupling Agent Using Micro Flow Reactors and Its Application in Dentistry

In dentistry, a wide range of materials is available for restorative treatment; a typical product of such restorative materials mainly consists of radically polymerizable monomer(s) and inorganic filler(s) (for added physical strength), as well as a surface modifier (e.g. silane coupling agent) for improved affinity between monomer and filler. It is favorable to use an optimal surface modifier depending on the respective restorative materials. However, commercially available surface modifiers, which are synthesized by the ton, are not always suited for what is required for properties of the many different dental restorative materials. As a potential solution to such a problem, we focused on the latest technology, “micro flow reactors” that enabled an on-demand low-volume synthesis of many types of surface modifiers. Using micro reaction fields of such flow reactors, we synthesized a novel long-chain silane coupling agent. Compared to the control system synthesized using a conventional reaction flask, the novel system enabled significant reduction in reaction time without inducing any major side reactions. A dental composite resin that was treated with the novel coupling agent exhibited higher toughness, suggesting that such a silane coupling agent was an effective surface modifier.

Efficient Green Synthesis of N′-Benzylidene-2-(2-Fluorobiphenyl) Propanehydrazides: Crystal Structure and Anti-Oxidant Potential

For the synthesis of N′-benzylidene-2-(2-fluorobiphenyl)propanehydrazides, 2-(2-fluorobiphenyl-4-yl)propanoic acid was esterified to methyl 2-(2-fluorobiphenyl-4-yl)propanoate under microwave irradiation followed by hydrazinolysis. This hydrazide was then reacted in an ultrasonic bath with different benzaldehydes to afford a series of N′-benzylidene-2-(2-fluorobiphenyl)propanehydrazides. Comparison of both the conventional and ultrasound assisted reactions indicates a significant reduction in reaction times and improvement in yields. Besides chemical characterisation and X-ray crystallography, all the synthesised compounds were evaluated for their anti-oxidant potential (total anti-oxidant activity, ferric reducing antioxidant power and total phenolic content) and most of them were found to have useful potential for pharmaceutical applications especially derivative bearing 2-hydroxy substituents.

Dopaminergic genetic variation moderates effect of nicotine on cigarette reward self-report

Aims: Youth with a family history of substance use disorders (SUD) oftenhave particular emotional andbehavioral traits that are early predictors of later problem substance use. There is substantial evidence for a gender difference in risk trajectories such that females tend toward negative affectivity and males tend toward impulsivity. Gender differences in substance use are also evident during adolescence, concurrent with the appearance of genderbased developmental differences in the brain, indicating theremay also be gender-specific neural predictors in those at-risk for developing SUD. Methods: Longitudinal fMRI was conducted in males (n=18) and females (n=18) with a family history of SUD starting at ages 8–13 yrs. Participants performed an emotional arousal word task during fMRI at 1to 2-yr intervals (3–4 scans/participant), covering the age range of 8–17.5 yrs. Emotional words were positive, negative, or neutral, and participants were required to press a button indicating they understood the word when it appeared on the screen. A voxel-by-voxel analysis was conducted in SPM8 using a multiple regression model, designed to represent mixed linear effects and identify age-related changes between groups. Results: For performance measures, females demonstrated a significant reduction in reaction time to negative, positive, and neutral words across age, while males showed no change. Significant age-related differences were found between groups in the right premotor cortex (BA6) and right amygdala for the negative vs. neutral contrast, where males showed a significant decrease in activation with age (premotor: p= .006; amygdala: p= .001) and females non-significantly increased in activation (premotor: p= .111; amygdala: p= .351). Conclusions: These results reveal developmental differences in brain functional responses in emotional arousal between males and females at-risk for SUD. These differencesmay underlie gender differences in behavioral risk trajectories for SUD. Financial support:R01DA027261, R01AA12217, R01AA07065, T32 DA007267-19, and T32 DA7268-22.

English

Oxidative desulphurization (ODS) enables attainment of ultra-low sulphur content in diesel fuels by oxidation of refractory sulphur compounds that are difficult to remove with hydrodesulphurization when the sulphur content needs to be attained below 10 mg kg–1. In this work, the effect of the process conditions of ultrasound-assisted ODS (using N, N- dimethylformamide and methanol as extraction solvents) on real diesel fuels was researched. The experiments were conducted in a batch reactor with hydrogen peroxide as oxidant and acetic acid as catalyst. Temperature increase, reaction time extension, and increase in the amount of dibenzothiophene (DBT) in real diesel fuels showed a positive impact on the ODS process efficiency. Comparison of ultrasound-assisted ODS and ODS in a mechanically stirred system revealed a significant reduction in reaction time. The very low sulphur concentrations (3 mg kg–1) in the product obtained after 30 minutes of oxidation confirmed high efficiency of the oxidative desulphurization.

Genetic determinants of cognitive responses to caffeine drinking identified from a double-blind, randomized, controlled trial

The widely observed between-subject variability in cognitive responses to coffee may have a genetic basis.We evaluated cognitive responses to caffeine throughout three complex cognitive tasks assessing different subdomains of attention, namely Alerting and Orienting (Categorical Search Task) and Executive Control (Stroop Task and Eriksen Flanker Task). We explored whether they are influenced by gene variants affecting adenosine metabolism or catecholamine receptors.We recruited 106 healthy male subjects who were administered, in a double-blind design, 40mL of either a decaffeinated coffee preparation plus 3mg/kg caffeine (caf) or the corresponding vehicle (decaf). The protocol was repeated 24h later with the alternative preparation. Cognitive tasks were performed between 30min and 2h after caf or decaf administration. Each subject underwent ambulatory blood pressure monitoring for 2h. Blood samples were collected for genetic evaluations and for plasma caffeine and catecholamines measures.We found a significant reduction of reaction times in two of the cognitive tasks (Categorical Search Task and Stroop Task) after caf compared with decaf, indicating that caffeine, on average, improved the attention level in the domains under investigation. We also found, however, a great inter-individual variability in the cognitive performance responses to caffeine. In exploring genetic sources for such variability, we found a relation between polymorphisms of adenosine A2A and the caffeine effects on the attentional domains of Orienting and Executive control.In conclusion, variability in the attentional response to coffee may be partly explained by genetic polymorphisms of adenosine and adrenergic receptors.

Cu-promoted sydnone cycloadditions of alkynes: scope and mechanism studies.

Cu salts have been found to promote the cycloaddition reaction of sydnones and terminal alkynes, providing significant reduction in reaction times. Specifically, the use of Cu(OTf)2 is found to provide 1,3-disubstituted pyrazoles, whereas simply switching the promoter system to Cu(OAc)2 allows the corresponding 1,4-isomers to be produced. The mechanism of the Cu-effect in each case has been investigated by experimental and theoretical studies, and they suggest that Cu(OTf)2 functions by Lewis acid activation of the sydnone, whereas Cu(OAc)2 promotes formation of reactive Cu(I) acetylides.

Synthesis and spectroscopic characterization of a new tripodal hexadentate iron chelator incorporating catechol units

We report the synthesis and physicochemical properties of a new tripodal hexadentate chelator (catTHC) synthesized by reaction of a flexible tripodal backbone with three bidentate catechol units. To improve the efficiency of the amide coupling reaction, classical conditions using two pairs of coupling reactants were tested, and a significant reduction in reaction time was achieved by using microwave irradiation with the reactants DCC/HOBt. Subsequent removal of the benzyl protecting groups using BCl3 in dichloromethane provided the final chelator in good yield. The acid–base properties of catTHC in aqueous solution and the affinity of the ligand towards iron(III) were investigated at variable pH and in the presence of iron(III) using spectroscopic methods. The hexadentate ligand forms a 1:1 complex with iron(III) whose stability constant was determined by competition with EDTA. The values obtained for the stability constant and pFe3+ are logβ110=36.70 and pFe3+=26.7.

THF: an efficient electron donor in continuous flow radical cyclization photocatalyzed by graphitic carbon nitride.

Mesoporous graphitic carbon nitride (mpg-C3 N4 ) was found to be an efficient heterogeneous photocatalyst for the metal-free radical cyclization of 2-bromo-1,3-dicarbonyl compounds. Reactions leading to functionalized cyclopentanes proceed under mild conditions and can be conducted in a continuous flow photoreactor. Compared to the batch reaction, the use of a continuous flow reactor resulted in a significant reduction in reaction time (complete conversion of 0.04 mmol of substrate in a batch was achieved after 4 h, whereas in a flow reactor the same amount of substrate was fully converted into a product within 40 min). Mechanistic studies of the reaction showed that THF plays not only the role of solvent, but is also a crucial hydrogen and electron donor.

Optimization of microwave-assisted synthesis of cyclodextrin nanosponges using response surface methodology

The reaction of polymerization of cyclodextrins with suitable polyfunctional agents leads to highly cross linked porous structures, referred to as cyclodextrin nanosponges. The conventional heating approach for the synthesis of nanosponges can lead to nonuniform reaction conditions caused by sharp thermal gradients in the bulk solution. In this work, we present a facile method for the synthesis of cyclodextrin nanosponges by microwave irradiation with significant reduction in reaction time. Response surface methodology and Box–Behnken design were used for the optimization of the process parameters including microwave power level (A), reaction time (B) and stirring speed (C). Two dependent variables practical yield and particle size were measured as responses. Mathematical equations and response surface plots were used to relate the dependent variables with independent variables. The optimization model predicted a yield of 96.5287 % and particle size of about 152.355 nm with A, B and C levels of 508.22, 83.55 and 1,471.55 respectively. The observed responses of the optimized process were in close agreement with the predicted values. Three confirmation batches of cyclodextrin nanosponges were synthesized under optimized conditions. The Fourier transformed infrared spectra of nanosponges showed a characteristic peak of the carbonate group at around 1,750 cm−1 which confirms the formation of nanosponges. TGA revealed the stability of obtained nanosponges up to 325 °C. The nanosponges obtained by microwave irradiation exhibited a higher degree of crystallinity. Dimension of the crystal lattice was found to be equal to 0.70 nm. TEM image confirmed the spherical shape and the particle size range of about 153 nm. Compared to conventional heating method, microwave method resulted in four folds reduction in reaction time and provided with particles of homogeneous size distribution and uniform crystallinity.

Microwave-assisted methods for the synthesis of pentacyclo[5.4.0.02,6.03,10.05,9]undecylamines

Efficient methodologies for the preparation of pentacyclo[5.4.0.02,6.03,10.05,9]undecane (PCU) amine derivatives are described via microwave-assisted synthesis. The obtained results revealed that microwave-assisted synthetic procedures under controlled conditions (power, temperature and time) are very convenient, high yielding, efficient and low-cost methods for the preparation of PCU amine derivatives. The new methods show several advantages including operational simplicity, good performance, significant reduction in reaction time, less by-product formation and easier purification.

Site-Dependent Effects of tDCS Uncover Dissociations in the Communication Network Underlying the Processing of Visual Search

BackgroundThe right posterior parietal cortex (rPPC) and the right frontal eye field (rFEF) form part of a network of brain areas involved in orienting spatial attention. Previous studies using transcranial magnetic stimulation (TMS) have demonstrated that both areas are critically involved in the processing of conjunction visual search tasks, since stimulation of these sites disrupts performance. ObjectiveThis study investigated the effects of long term neuronal modulation to rPPC and rFEF using transcranial direct current stimulation (tDCS) with the aim of uncovering sharing of these resources in the processing of conjunction visual search tasks. MethodsParticipants completed four blocks of conjunction search trials over the course of 45 min. Following the first block they received 15 min of either cathodal or anodal stimulation to rPPC or rFEF, or sham stimulation. ResultsA significant interaction between block and stimulation condition was found, indicating that tDCS caused different effects according to the site (rPPC or rFEF) and type of stimulation (cathodal, anodal, or sham). Practice resulted in a significant reduction in reaction time across the four blocks in all conditions except when cathodal tDCS was applied to rPPC. ConclusionsThe effects of cathodal tDCS over rPPC are subtler than those seen with TMS, and no effect of tDCS was evident at rFEF. This suggests that rFEF has a more transient role than rPPC in the processing of conjunction visual search and is robust to longer-term methods of neuro-disruption. Our results may be explained within the framework of functional connectivity between these, and other, areas.