Distinct Active Regions Research Articles

Viola stocksii: A rich source of antioxidant and anti-inflammatory flavonoid glycosides with converged therapeutic potential against SARS-CoV-2 MPro, spike trimer, and surface glycoproteins

This research presents the first comprehensive investigation into the phytochemical and nutraceutical properties of Viola stocksii. The study aimed to identify the therapeutic efficacy and bioactive constituents of this medicinal herb, traditionally used as an herbal tea for managing respiratory and abdominal issues in remote areas of Pakistan. The therapeutic efficacy of the plant was assessed as an anti-oxidant-rich health tonic coupled with anti-inflammatory and immunomodulatory activities against COVID-19 and its evolving variants. The study involved sequential extraction, bio-assay guided fractionation, isolation, characterization, and biological evaluation. Preliminary in vitro studies have demonstrated that polar fractions of the plant possess significant antioxidant and antiinflammatory potential. A diverse combination of chromatographic techniques (Diaion resin HP-20, Sephadex LH-20, ODS-C18, and RP-HPLC) facilitated the purification of active constituents of the plant. Comprehensive analysis of NMR (1H, 13C, and 2D NMR) and mass (EIMS, HR-EIMS, and FAB-HRMS) spectral data lead to characterize the isolated compounds (1–4) as flavonoid glycosides. Results from in vitro and in-silico evaluations revealed that the isolated glycosides exhibit high antioxidant, antiinflammatory, and immunomodulatory activities, which synergistically show promising potential in combating SARS-CoV-2 variants. Besides MPro, therapeutic potential against two unexplored proteins i.e. the spike trimer (7WZ1) and surface glycoproteins (7QTJ) was studied for the first time. Kaempferol (KamGluαRh) and quercetin (QurGluαRh) carrying rutinoside, were identified as the most active constituents of the plant, with the highest binding affinities in the range of −10 to −13 kcal/mol. Ten distinct active regions were explored on the spike trimer, including strong binding affinity with the essential RBD region, spike head, and tail of the protein. MD simulation validated the stability of Mpro-KamGluαRh and Mpro-QurGluαRh complexes evidenced by an average RMSD of 0.2 nm led to the mechanistic understanding of Mpro inhibition. ADMET and pharmacokinetic studies authenticated the therapeutic ability and drug-likeness profiling of all extracted compounds. Results revealed the beneficial role of glycosides in boosting the medicinal effectiveness of flavonoids and the potential of Viola stocksii as an immunity booster against respiratory infections like COVID-19.

Readon: a novel algorithm to identify read-through transcripts with long-read sequencing data.

There are many clustered transcriptionally active regions in the human genome, in which the transcription complex cannot immediately terminate transcription at the upstream gene termination site, but instead continues to transcribe intergenic regions and downstream genes, resulting in read-through transcripts. Several studies have demonstrated the regulatory roles of read-through transcripts in tumorigenesis and development. However, limited by the read length of next-generation sequencing, discovery of read-through transcripts has been slow. For long but also erroneous third-generation sequencing data, this study developed a novel minimizer sketch algorithm to accurately and quickly identify read-through transcripts. Readon initially splits the reference sequence into distinct active regions. It employs a sliding window approach within each region, calculates minimizers, and constructs the specialized structured arrays for query indexing. Following initial alignment anchor screening of candidate read-through transcripts, further confirmation steps are executed. Comparative assessments against existing software reveal Readon's superior performance on both simulated and validated real data. Additionally, two downstream tools are provided: one for predicting whether a read-through transcript is likely to undergo nonsense-mediated decay or encodes a protein, and another for visualizing splicing patterns. Readon is freely available on GitHub (https://github.com/Bulabula45/Readon).

Eruptivity in Solar Flares: The Challenges of Magnetic Flux Ropes

Abstract Two new schemes for identifying field lines involved in eruptions, the r-scheme and q-scheme, are proposed to analyze the eruptive and confined nature of solar flares, as extensions to the original r m scheme proposed in Lin et al. Motivated by three solar flares originating from NOAA Active Region 12192 that are misclassified by r m , we introduce refinements to the r-scheme employing the “magnetic twist flux” to approximate the force balance acting on a magnetic flux rope (MFR); in the q-scheme, the reconnected field is represented by those field lines that anchor in the flare ribbons. Based on data obtained by the Solar Dynamics Observatory/Helioseismic and Magnetic Imager, the coronal magnetic field for 51 flares larger than M5.0 class, from 29 distinct active regions, is constructed using a nonlinear force-free field extrapolation model. Statistical analysis based on linear discriminant function analysis is then performed, revealing that despite both schemes providing moderately successful classifications for the 51 flares, the coronal mass ejection-eruptivity classification for the three target events can only be improved with the q-scheme. We find that the highly twisted field lines and the flare-ribbon field lines have equal average force-free constant α, but all of the flare-ribbon-related field lines are shorter than 150 Mm in length. The findings lead us to conclude that it is challenging to distinguish the MFR from the ambient magnetic field using any quantity based on common magnetic nonpotentiality measures.

Partial oxidation of methanol to formaldehyde in an annular reactor

A structured reactor with annular configuration was applied for studying methanol oxidation to formaldehyde over silver. By eliminating gas phase reactions, high formaldehyde selectivity (93–97%) was obtained at low methanol and oxygen conversion under practically isothermal reaction conditions. CH2O and CO2 were the only carbon containing products, and both may be claimed as primary products along with H2. It also proves that CO is formed by homogenous decomposition of CH2O and should not be considered a main precursor to CO2, as assumed in several reaction mechanisms. The analysis of H2/CO2 ratio as a function of temperature provides an estimate of contributions from dehydrogenation and partial oxidation of methanol, and clearly suggests presence of a dehydrogenation pathway to CH2O. Extracting kinetic parameters is challenging due to a correlation between activity, oxygen dissolution, and silver restructuring and morphology and its dependence on temperature. Nevertheless, the data indicate 1st order with respect to oxygen. Conditioning by reaction at high temperature followed by a temperature ramp was performed to minimize the impact of a gradually changing Ag catalyst. The resulting Arrhenius analysis implies two distinct regions of activity. The apparent activation energy was estimated to 41 kJ/mol for the high temperature region, a value close to the activation energy for oxygen diffusion in silver at high temperature. The investigation demonstrates benefits of using an annular reactor configuration in bridging lab scale investigations with industrial conditions. Collecting reaction data at low oxygen conversion is enabled, which has not been achievable in conventional lab scale reactors this far.

Rate-Limiting Steps Elucidated By Electrochemical Impedance Spectroscopy of a Yttria-Stabilized Zirconia 2-in-1 Temperature and Oxygen Gas Sensor Measured at Extreme Temperatures

Introduction Yttria-stabilized zirconia (YSZ) is known for its good ionic conductivity, essentially being synonymous with the term “lambda sensor”. Automotive lambda sensors have been fabricated with YSZ as the electrolyte for 30+ years and have operated in a temperature region of 600oC to 800oC. There is an increasing demand for higher operating temperature sensors, specifically a 2-in-1 temperature and oxygen sensor which is stable, selective, and sensitive in extreme environments. However, there remains a disagreement among scholars about the effects on oxygen vacancy activation energy at temperatures higher than 800oC. Also, the rate-limiting step of oxygen reduction on the platinum electrode is not inherently clear. A 2-in-1 temperature and oxygen sensor was fabricated and characterized with the analysis of electrochemical impedance spectroscopy (EIS), DC resistance, and open circuit potential measurements at temperatures between 600oC and 1200oC. The temperature dependence on individual activation energies within the sensor was elucidated directly through these techniques. Methods Yttria-stabilized zirconia (MTI Corp) was employed as the solid-state electrolyte in sensor fabrication, with the primary electrode material as porous platinum (ESL 5570). Platinum paste was screen printed onto planar YSZ substrates in an interdigitated electrode configuration, then fired at 1500oC for 2 hours in nitrogen atmosphere (1 atm). The sensor was placed in a ThermoScientific tube furnace capable of reaching 1500oC, with mass flow controllers varying oxygen gas concentration throughout electrical measurements. Platinum foil acted as a Faraday cage around the sensor to shield from furnace inductive fluctuations and minimize noise during low frequency EIS measurements. A thermocouple placed next to the sensor validated furnace operating temperature and cooling endcaps on the furnace tube created a natural temperature gradient between sensor placement and the electrical connections outside of the furnace. Figure 1 displays the environmental testing setup. Results and Conclusions Figure 2a displays an impedance Nyquist spectrum that contains real and imaginary components of impedance measured at 0.21 atm PO2, where electrolyte resistance decreases with an increase in temperature. Figure 2b displays the Arrhenius plot of isolated YSZ electrolytic resistance extracted from figure 2a, where there are distinct activation regions at moderate and high temperatures. In agreement with Badwal [1], the shift to lower EA at higher temperatures was due to a gradual transition between an association region where oxygen vacancies are bound to dopant cations, and a dissociation region where vacancies are free and mobile.At a known temperature, EIS also elucidates oxygen concentration dependence on sensor electrode resistance. Figure 3a shows sensor electrode resistance, fitted from figure 2a, as a function of oxygen concentration. Investigating the oxygen reduction reaction (ORR) variation on platinum at various temperature regions, it is suggested that ORR on platinum is co-limited by oxygen adsorption and by oxygen transport along the surface of the electrode, in agreement with Adler [2]. Figure 3b shows that electrode 2 is dominant at temperatures below 1050oC, indicative of oxygen diffusion limitation on the surface and through platinum. Electrode 1 is dominant at temperatures above 1050oC, where dissociative adsorption of oxygen on the electrode surface is predominant.

Facile high-temperature synthesis of weakly entangled polyethylene using a highly activated Ziegler-Natta catalyst

A Polyhedral oligomeric silsesquioxane (POSS) modified Ziegler-Natta catalyst is reported to synthesize the weakly entangled ultra-high molecular weight polyethylene at a high temperature and with a high activity. Incorporation of POSS can form numbers of aggregates with a mean size of 48 nm adsorbing on the surface of SiO2. The structure of nanoaggregates is evidenced by the experiments and theoretical calculations where one POSS can coordinate with multiple MgCl2 molecules serving as an electric donor to the further immobilized TiCl4. The catalyst is thus featured by two distinct active regions positioned in the POSS/MgCl2 nanoaggregates and δ-MgCl2, respectively. The former regions present extremely low activity on ethylene polymerization, which function as horizontal separators for isolating the active TiCl4 sites and the growing chains. This catalyst exhibits an exceptional activity (i.e. 1.3 × 106 gPE molTi−1 h−1 bar−1) for the synthesis of weakly entangled polyethylene at 60 °C.

I know I’ve seen you before: Distinguishing recent-single-exposure-based familiarity from pre-existing familiarity

This study examines how individuals differentiate recent-single-exposure-based familiarity from pre-existing familiarity. If these are two distinct cognitive processes, are they supported by the same neural bases? This study examines how recent-single-exposure-based familiarity and multiple-previous-exposure-based familiarity are supported and represented in the brain using functional MRI. In a novel approach, we first behaviorally show that subjects can divide retrieval of items in pre-existing memory into judgments of recollection and familiarity. Then, using functional magnetic resonance imaging, we examine the differences in blood oxygen level dependent activity and regional connectivity during judgments of recent-single-exposure-based and pre-existing familiarity. Judgments of these two types of familiarity showed distinct regions of activation in a whole-brain analysis, in medial temporal lobe (MTL) substructures, and in MTL substructure functional-correlations with other brain regions. Specifically, within the MTL, perirhinal cortex showed increased activation during recent-single-exposure-based familiarity while parahippocampal cortex showed increased activation during judgments of pre-existing familiarity. We find that recent-single-exposure-based and pre-existing familiarity are represented as distinct neural processes in the brain; this is supported by differing patterns of brain activation and regional correlations. This spatially distinct regional brain involvement suggests that the two separate experiences of familiarity, recent-exposure-based familiarity and pre-existing familiarity, may be cognitively distinct.

Neuroanatomical assessment of the impact of negative emotion on implicit memory in patients with obsessive compulsive disorder.

We performed functional magnetic resonance imaging (fMRI) to discriminate the differential brain activation patterns in patients with obsessive compulsive disorder (OCD) and healthy controls during implicit retrieval tasks with emotionally neutral and unpleasant words. Sixteen patients with OCD (mean age: 31.4±10.1 years) and 16 healthy controls (mean age: 32.6±5.8 years) with no history of neurological or psychiatric illness underwent 3-T fMRI. The stimulation paradigm consisted of the following cycle: rest, encoding of a string of two-syllable words, rest, and retrieval of the previously encoded words with the first consonant omitted. During the implicit retrieval task with emotionally neutral words, no distinct brain activity was observed in either the patients with OCD or healthy controls. On the other hand, during the retrieval task with unpleasant words, the patients with OCD showed predominant activity in the superior/middle temporal pole, medial superior frontal gyrus, and orbitofrontal cortex (uncorrected p<0.001, extent threshold: 30 voxels), whereas the healthy controls did not show any distinct regions of activation. This study revealed the differential brain activation patterns between patients with OCD and healthy controls during implicit memory tasks with unpleasant words. Our results suggest that the impact of negative emotion on implicit memory task may be associated with the symptomatology of OCD. This finding may be helpful for understanding the neural mechanisms that underlie implicit memory retrieval, particularly the interaction between emotion and cognition, in patients with OCD.

Polyethylene with Reverse Co‐monomer Incorporation: From an Industrial Serendipitous Discovery to Fundamental Understanding

A triethylaluminium(TEAl)-modified Phillips ethylene polymerisation Cr/Ti/SiO2 catalyst has been developed with two distinct active regions positioned respectively in the inner core and outer shell of the catalyst particle. DRIFTS, EPR, UV-Vis-NIR DRS, STXM, SEM-EDX and GPC-IR studies revealed that the catalyst produces simultaneously two different polymers, i.e., low molecular weight linear-chain polyethylene in the Ti-abundant catalyst particle shell and high molecular weight short-chain branched polyethylene in the Ti-scarce catalyst particle core. Co-monomers for the short-chain branched polymer were generated in situ within the TEAl-impregnated confined space of the Ti-scarce catalyst particle core in close proximity to the active sites that produced the high molecular weight polymer. These results demonstrate that the catalyst particle architecture directly affects polymer composition, offering the perspective of making high-performance polyethylene from a single reactor system using this modified Phillips catalyst.

Cortical activity differs between position- and force-control knee extension tasks.

Neural control differs between position- and force-control tasks as evident from divergent effects of fatigue and pain. Unlike force-control tasks, position-control tasks focus on a postural goal to maintain a joint angle. Cortical involvement is suggested to be less during postural control, but whether this differs between position- and force-control paradigms remains unclear. Coherence estimates the functional communication between spatially distinct active regions within the cortex (cortico-cortical coherence; CCC) and between the cortex and muscles (corticomuscular coherence; CMC). We investigated whether cortical involvement differed between force-control and more posturally focused, position-control tasks. Seventeen adults performed position- and force-control knee extensor efforts at a submaximal load (10% maximum voluntary contraction). Surface electromyography was recorded from the right knee extensor and flexor muscles and brain activity using electroencephalography (EEG). CCC and CMC in the beta (13-30Hz) and gamma (30-45Hz) frequency bands were calculated between combinations of intra- and inter-hemispheric pairs of electrodes, and between four EEG electrodes that approximated the left motor cortical area, and right knee extensor EMG, respectively. Differences in EEG power and muscle activity were also calculated. CCC was greater across distributed regions in the force-control task. Beta EEG power in the left hemisphere was higher for the position-control task. Although averaged CMC data differed between tasks, there was no task difference for individual CMC data. Muscle activity and force did not differ between tasks. The results demonstrate differential cortical contributions to control force- versus position-control tasks. This might contribute to differences in performance outcomes of these tasks that have been shown previously.

A meta-analysis of functional reading systems in typically developing and struggling readers across different alphabetic languages.

Functional neuroimaging research has identified multiple brain regions supporting reading-related activity in typical and atypical readers across different alphabetic languages. Previous meta-analyses performed on these functional magnetic resonance imaging findings typically report significant between-group contrasts comparing typical readers and readers with reading difficulty or a clinical diagnosis of developmental dyslexia. In order to advance our understanding of cross-linguistic convergence of reading-related brain activations for these reader groups, analyses using activation likelihood estimation were carried out separately for typical and atypical readers who ranged from children to adults. Contrasts were analyzed for tasks involving rhyming or reading of letter or word stimuli presented visually in English, Dutch, Italian, German, French, or Norwegian. Typical readers showed reliable activation in only left lateralized regions, including the inferior frontal area, precentral area and middle temporal gyrus. Atypical readers also showed activation in the left inferior frontal area and precentral region, in addition to significant activations in the right hemisphere, including the superior, medial and inferior frontal regions, lingual gyrus and the inferior occipital area. These results distinguish between typical and atypical reader group activations, showing common and distinct regions of activation when engaged in reading-related activities, extending previous meta-analyses on identifying brain regions relevant to reading to include cross-linguistic analyses for alphabetic scripts. Results support the universality of a signature pattern of brain activation in developmental dyslexia across alphabetic languages.

Deconstructing the default: Cortical subdivision of the default mode/intrinsic system during self‐related processing

Recent brain imaging research has highlighted a new global system of areas termed the Default Mode network (DM), which appears to specialize in intrinsically oriented functions. However, it is still unresolved to what extent this system contains functional subsystems as in the better known sensory and motor cortices. Here, we report that functional subdivisions can be revealed within individual nodes of the DM, such as the Inferior Parietal Lobule (IPL), through the use of different categories of self-oriented tasks. Subjects underwent BOLD fMRI scans during which they were asked to recall self-related positive and negative information in the categories of people and food. These tasks elicited distinct regions of activation within the DM. Importantly, the observed activations were above the activity level in the baseline, no-task condition for these regions. The main subdivision within the DM was observed in the inferior and posterior parietal cortex. Analysis of coherent resting state fluctuations (functional connectivity analysis) revealed that these regions of activation were part of a distinct network of regions within the DM. These results argue against viewing the DM as a unitary system, and are compatible with the notion that, similar to the rest of the cerebral cortex, the DM consists of distinct, functionally specialized subregions.

Stimulus Site and Modality Dependence of Functional Activity within the Human Spinal Cord

Chronic pain is thought to arise because of maladaptive changes occurring within the peripheral nervous system and CNS. The transition from acute to chronic pain is known to involve the spinal cord (Woolf and Salter, 2000). Therefore, to investigate altered human spinal cord function and translate results obtained from other species, a noninvasive neuroimaging technique is desirable. We have investigated the functional response in the cervical spinal cord of 18 healthy human subjects (aged 22-40 years) to noxious thermal and non-noxious tactile stimulation of the left and right forearms. Physiological noise, which is a significant source of signal variability in the spinal cord, was accounted for in the general linear model. Group analysis, performed using a mixed-effects model, revealed distinct regions of activity that were dependent on both the side and the type of stimulation. In particular, thermal stimulation on the medial aspect of the wrist produced activity within the C6/C5 segment ipsilateral to the side of stimulation. Similar to data recorded in animals (Fitzgerald, 1982), painful thermal stimuli produced increased ipsilateral and decreased contralateral blood flow, which may reflect, respectively, excitatory and inhibitory processes. Nonpainful punctate stimulation of the thenar eminence provoked more diffuse activity but was still ipsilateral to the side of stimulation. These results present the first noninvasive evidence for a lateralized response to noxious and non-noxious stimuli in the human spinal cord. The development of these techniques opens the path to understanding, at a subject-specific level, central sensitization processes that contribute to chronic pain states.

Neural systems for guilt from actions affecting self versus others

Guilt is a core emotion governing social behavior by promoting compliance with social norms or self-imposed standards. The goal of this study was to contrast guilty responses to actions that affect self versus others, since actions with social consequences are hypothesized to yield greater guilty feelings due to adopting the perspective and subjective emotional experience of others. Sixteen participants were presented with brief hypothetical scenarios in which the participant's actions resulted in harmful consequences to self (guilt-self) or to others (guilt-other) during functional MRI. Participants felt more intense guilt for guilt-other than guilt-self and guilt-neutral scenarios. Guilt scenarios revealed distinct regions of activity correlated with intensity of guilt, social consequences of actions, and the interaction of guilt by social consequence. Guilt intensity was associated with activation of the dorsomedial PFC, superior frontal gyrus, supramarginal gyrus, and anterior inferior frontal gyrus. Guilt accompanied by social consequences was associated with greater activation than without social consequences in the ventromedial and dorsomedial PFC, precuneus, posterior cingulate, and posterior superior temporal sulcus. Finally, the interaction analysis highlighted select regions that were more strongly correlated with guilt intensity as a function of social consequence, including the left anterior inferior frontal gyrus, left ventromedial PFC, and left anterior inferior parietal cortex. Our results suggest these regions intensify guilt where harm to others may incur a greater social cost.

Multi‐color light emitting diode using polarization‐induced tunnel junctions

AbstractA multi‐color light emitting diode (LED) using two distinct active regions connected via a tunnel junction was grown by rf‐plasma‐assisted molecular beam epitaxy. The LED is contacted through n‐type layers, one of which provides efficient contact to a p‐type layer via a second tunnel junction. The tunnel junctions used in the structure use the high polarization fields found in the III‐nitrides material system to narrow the depletion width of the junction. Two peaks at 405 nm and 490 nm are observed in the electroluminescence spectrum of the LED, and current‐voltage characteristics indicate a turn‐on voltage of roughly 7.5 V and dynamic series resistance of 19 Ω at 80 mA for a 300 μm square device. (© 2007 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Distinct regions of medial rostral prefrontal cortex supporting social and nonsocial functions.

While some recent neuroimaging studies have implicated medial rostral prefrontal cortex (MPFC) in 'mentalizing' and self-reflection, others have implicated this region in attention towards perceptual vs self-generated information. In order to reconcile these seemingly contradictory findings, we used fMRI to investigate MPFC activity related to these two functions in a factorial design. Participants performed two separate tasks, each of which alternated between 'stimulus-oriented phases' (SO), where participants attended to task-relevant perceptual information, and 'stimulus-independent phases' (SI), where participants performed the same tasks in the absence of such information. In half of the blocks ('mentalizing condition'), participants were instructed that they were performing these tasks in collaboration with an experimenter; in other blocks ('non-mentalizing condition'), participants were instructed that the experimenter was not involved. In fact, the tasks were identical in these conditions. Neuroimaging data revealed adjacent but clearly distinct regions of activation within MPFC related to (i) mentalizing vs non-mentalizing conditions (relatively caudal/superior) and (ii) SO vs SI attention (relatively rostral/inferior). These results generalized from one task to the other, suggesting a new axis of functional organization within MPFC.

Phonological processing in Chinese–English bilingual biscriptals: An fMRI study

Different activation loci have been reported for language processing in unilingual Chinese and unilingual English participants, as well as in bilingual readers of English and French, two alphabetic languages. Nevertheless, the extant imaging work on Mandarin–English bilinguals favors common neural substrates for English and Chinese, languages with contrasting oral and written forms. We investigated the phonological processes in reading for English–Chinese biscriptals using a homophone matching task with parallel behavioral ( n = 28) and fMRI ( n = 6) experiments. Unlike previous reports, we observed distinct regions of activation for Mandarin in the left and right frontal lobes, the left temporal lobe, and the right occipital lobe, plus distinct regions of activation for English bilaterally in both the frontal and parietal lobes. The implications of these novel findings are discussed with reference to language representation in bilinguals.

TATA-binding Protein-free TAF-containing Complex (TFTC) and p300 Are Both Required for Efficient Transcriptional Activation

Initiation of transcription of protein-encoding genes by RNA polymerase II was thought to require transcription factor TFIID, a complex comprising the TATA-binding protein (TBP) and TBP-associated factors (TAFs). In the presence of TBP-free TAF complex (TFTC), initiation of polymerase II transcription can occur in the absence of TFIID. TFTC contains several subunits that have been shown to play the role of transcriptional coactivators, including the GCN5 histone acetyltransferase (HAT), which acetylates histone H3 in a nucleosomal context. Here we analyze the coactivator function of TFTC. We show direct physical interactions between TFTC and the two distinct activation regions (H1 and H2) of the VP16 activation domain, whereas the HAT-containing coactivators, p300/CBP (CREB-binding protein), interact only with the H2 subdomain of VP16. Accordingly, cell transfection experiments demonstrate the requirement of both p300 and TFTC for maximal transcriptional activation by GAL-VP16. In agreement with this finding, we show that in vitro on a chromatinized template human TFTC mediates the transcriptional activity of the VP16 activation domain in concert with p300 and in an acetyl-CoA-dependent manner. Thus, our results suggest that these two HAT-containing co-activators, p300 and TFTC, have complementary rather than redundant roles during the transcriptional activation process.

Reading the mind in cartoons and stories: an fMRI study of ‘theory of mind’ in verbal and nonverbal tasks

Previous functional imaging studies have explored the brain regions activated by tasks requiring ‘theory of mind’—the attribution of mental states. Tasks used have been primarily verbal, and it has been unclear to what extent different results have reflected different tasks, scanning techniques, or genuinely distinct regions of activation. Here we report results from a functional magnetic resonance imaging study (fMRI) involving two rather different tasks both designed to tap theory of mind. Brain activation during the theory of mind condition of a story task and a cartoon task showed considerable overlap, specifically in the medial prefrontal cortex (paracingulate cortex). These results are discussed in relation to the cognitive mechanisms underpinning our everyday ability to ‘mind-read’.

Structure and catalytic activity of La 1− xFeO 3 system ( x=0.00, 0.05, 0.10, 0.15, 0.20, 0.25, 0.35) for the NO+CO reaction

Solids of the nominal formula La 1− x FeO 3 where x=0.00, 0.05, 0.10, 0.15, 0.20, 0.25, 0.35, and containing only the perovskite (small x) and the perovskite plus Fe 2O 3 crystal phases (large X) were examined in the catalytic reaction of (NO+CO). The solids were prepared by heating at T=1000°C under ∼10 −5 Torr vacuum and showed appreciable catalytic activity at temperatures from 280°C to 480°C when SV is ∼300 h −1. XRD analysis and Rietveld refinement showed that for x=0.00 and 0.05 only the perovskite phase is apparent. For x≥0.10 an additional crystal phase of Fe 2O 3 appears which increases with x up to a maximum of 4.1% at x=0.35. Moessbauer examination indicated that iron exists in the perovskite structure at x=0.00 and 0.05 but for x≥0.10 the extra-perovskite Fe 3+ increases proportional to the parameter x of the solids La 1− x FeO 3 and reaches 43% at x=0.35. These results are explained assuming that in the catalyst particles with x≥0.10 a Fe 2O 3 core of increasing size is covered by a LaFeO 3 shell. The sample LaFeO 3 showed lower catalytic activity for the NO+CO reaction than the rest of La 1− x FeO 3 solids. The Arrhenius plots showed two distinct regions of activity one at low temperature with high apparent activation energies and another at high temperature with lower apparent activation barriers. At low temperatures the low activity at x=0.00 is related to high apparent activation energies while for x≥0.05 the opposite is true. A detailed scrutinization of the apparent activation energies resulted in an estimation of the heats of adsorption of NO on LaFeO 3 and La 1− x FeO 3. The reaction of NO+CO also resulted in small amounts of N 2O which showed a maximum at ∼320°C. The dependence of N 2O production and elimination on the temperature made it possible to determine the activation energies of its formation as well as the heat of desorption of nitrogen from the catalyst surface. The catalytic activity of the solids is destroyed if they are heated under atmospheric conditions.