For the first time, it was demonstrated that the catalytic properties of semiconductors can be activated using an external electric field only. More particularly, the TiO2 and Fe2O3 were found to ...produce noticeable amounts of carbon monoxide from carbon dioxide – water vapor gas mixture under the electric field with the strength in the 104 V/cm range. The reported process, i.e. the activation of semiconductors using the electric field is more efficient than the utilization of UV–vis radiation in terms of energy efficiency and amount of products formed.
Display omitted
•Catalytic properties of semiconductors was activated using the external electric field only.•Wet CO2 was converted into CO over TiO2 and Fe2O3 in the presence of field in the 104 V/cm range.•The activity of investigated semiconductors depended on both surface and electronical properties.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Herein, we reported the method of synthesis of sodium titanates using metal-ammonia solution and their photocatalytic activity for the gas-phase reduction of carbon dioxide under visible light. The ...results of physicochemical measurements showed that the obtained samples resemble multiphase systems containing Na2Ti4O9, Na4Ti5O12, and Na0.8Ti4O8 of cylindrical forms. They demonstrated perfect adsorption of visible light and improved activity in the investigated process.
Display omitted
•Intercalation of sodium into titanium dioxide was performed using a solution of sodium metal in liquid ammonia.•Multiphase systems containing sodium titanates of different stoichiometry (Na2Ti4O9, Na4Ti5O12, and Na0.8Ti4O8) were formed.•Localization of sodium ions in titanium dioxide depended on its initial concentration in liquid ammonia.•Absorption of visible light and photocatalytic activity of titanium dioxide were greatly improved.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Ethanol steam reforming was studied over Ni supported catalysts. The effects of support (Al
2
O
3
, Al
2
O
3
–ZnO, and Al
2
O
3
–CeO
2
), metal loading, catalyst activation method, and ...steam-to-ethanol molar feed ratio were investigated. The properties of catalysts were studied by N
2
physisorption, TPD-CO
2
, X-ray diffraction, and temperature programmed reduction. After activity tests, the catalysts were analyzed by TOC analysis. The catalytic activity measurements showed that the addition either of ZnO SSor CeO
2
to alumina enhances both ethanol conversion and promotes selectivity towards hydrogen formation. The same effects were observed for catalysts with higher metal loadings. High process temperature and high water-to-ethanol ratio were found to be beneficial for hydrogen production. An extended catalyst stability tests showed no loss of activity over 50 h on reaction stream. The TOC analysis of spent catalysts revealed only insignificant amounts of carbon deposit.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Inhibitory control, the ability to suppress irrelevant thoughts or actions, is central to cognitive and social development. Protracted maturation of frontal brain networks has been reported as a ...major restraint for this ability, yet, young children, when motivated, successfully inhibit delayed responses. A better understanding of the age-dependent neural inhibitory mechanism operating during the
awaiting-to-respond
window in children may elucidate this conundrum. We recorded ERPs from children and parental adults to a visual-spatial working memory task with delayed responses. Cortical activation elicited during the first 1000 ms of the
awaiting-to-respond
window showed, as predicted by prior studies, early inhibitory effects in prefrontal ERPs (
P200,
160–260 ms) associated with top-down
attentional-biasing,
and later effects in parietal/occipital ERPs (
P300,
270–650 ms) associated with selective inhibition of task-irrelevant stimuli/responses and recurrent memory retrieval. Children successfully inhibited delayed responses and performed with a high level of accuracy (often over 90%), although, the prefrontal P200 displayed reduced amplitude and uniformly delayed peak latency, suggesting low efficacy of top-down
attentional-biasing
. P300, however, with no significant age-contrasts in latency was markedly elevated in children over the occipital/inferior parietal regions, with effects stronger in younger children. These results provide developmental evidence supporting the
sensorimotor recruitment
model of visual-spatial working memory relying on the occipital/parietal regions of the early maturing dorsal-visual network. The evidence is in line with the concept of age-dependent variability in the recruitment of cognitive inhibitory networks, complementing the former predominant focus on frontal lobes.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, ODKLJ, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Bullying victimization has a profound negative impact on a child’s emotional, social, and cognitive development. Childhood bullying victimization is reported across various social settings, ...suggesting common characteristics that increase a child’s vulnerability to victimization. It is critical to identify early markers of such vulnerability to design preventative tools. Comprehensive semi-structured clinical interviews from mothers of child-victims and non-engaged control children included assessment of early developmental rituals and behavioral inhibition to social novelty, as potential behavioral correlates of anxiety. Neuropsychological and clinical assessment tools were used, and resting state spectral resting state EEG (rsEEG) was recorded. Increased frequency/severity of early developmental rituals and behaviorally inhibited responses to social novelty were apparent in all child-victims, alongside significantly reduced power of ventral prefrontal brain rsEEG alpha oscillations (8–13 Hz). This triad of findings, in line with prior studies, suggested an elevated early childhood anxiety, which, as current findings indicate, may be a cross-diagnostic marker of increased risk for life-long bullying victimization. Gaining insight into early childhood markers of anxiety may meaningfully complement neuropsychiatric prognosis and preventative efforts.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Monometallic copper and bimetallic palladium–copper catalysts supported on ZnO–Al
2
O
3
, CeO
2
–Al
2
O
3
and ZrO
2
–Al
2
O
3
were prepared by conventional impregnation method and tested in the ...methanol synthesis reaction in a gradient less reactor under elevated pressure (3.5 MPa) at 220°C. The physicochemical properties of prepared catalytic systems were studied using BET, TPR-H
2
, TPD-NH
3
, XRD, SEM-EDS and FT-IR techniques. The results of XRD and SEM-EDS measurements showed the formation of Pd–Cu alloy during the activation of bimetallic catalysts. It was found that the formed alloy was responsible for the improved activity and selectivity of catalysts in the studied reaction. Among investigated catalysts, the highest formation rate of methanol was observed with 2%Pd–20%Cu/ZnO–Al
2
O
3
system. Based on the results of FT-IR measurements it can be concluded that hydrogen molecules adsorb dissociatively on the metallic copper surface to form hydrogen atoms, increasing the hydrogen spillover effect on the metal-support interface. In contrast, CO
2
adsorb on the oxygen vacancies of the support to form carbonates, which can further undergo hydrogenation to methanol.
Introduction
Juvenile idiopathic arthritis is the most common disease in pediatric rheumatology. It is characterized by chronically progressive joint destruction. The temporomandibular joints (TMJs) ...are involved in up to 87% of patients and may take an asymptomatic course in 69% of cases. Other than contrast-enhanced magnetic resonance imaging (MRI), there are no reliable screening symptoms or non-invasive procedures available to diagnose the inflammation in its acute form. The goal of this study was to establish an imaging-based classification system for TMJ erosion via MRI and cone-beam computed tomography (CBCT) in an effort to improve indication-specific treatment approaches and to facilitate the comparison of findings.
Materials and methods
A total of 46 patients were included. Contrast-enhanced MRI and CBCT images obtained during treatment by pediatric rheumatologists and orthodontists were available from 23 patients with juvenile idiopathic arthritis. We devised a classification system combining the findings of both imaging techniques based on this patient sample in comparison with CBCT findings from an age- and gender-matched group of 23 non-arthritis patients, taking into consideration the available literature and administration of contrast medium.
Results
Our cohort of 46 patients comprised 60% female and 40% male patients with a mean age of 14 years, providing a total of 92 TMJs for evaluation. We were able to apply the findings efficiently and conveniently to this classification system with no relevant interobserver differences. Mild structural abnormalities were noted in 21% of TMJs in the control group, whereas 83% of TMJs in the arthritis group exhibited severe anomalies, including cases of extreme destruction. Age and gender did not affect the degree of destruction significantly.
Conclusion
This is the first classification system to link CBCT and MRI with the use of contrast medium. Contrast-enhanced MRI is an internationally recognized technique that permits acute inflammation to be unequivocally diagnosed. Although structural erosion of the TMJs in our arthritis group was generally severe and significant, we were surprised to observe some cases that were clinically asymptomatic.
Full text
Available for:
CMK, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This review describes features of the structure of carbon nanotubes, their principal characteristics, methods of synthesis, and regions of potential application. Most attention has been paid to the ...use of nanotubes in catalysis. Examples are given of the functionalization of nanotubes and also their use as catalysts, catalytic additives, and catalyst supports.
Full text
Available for:
DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Resting-state activity has been used to gain a broader understanding of typical and aberrant developmental changes. However, the developmental trajectory of resting-state activity in relation to ...cognitive performance has not been studied in detail. The present study assessed spectral characteristics of theta (5–8 Hz) and alpha (9–13 Hz) frequency bands during resting-state in a priori selected regions of the frontoparietal network (FPN). We also examined the relationship between resting-state activity and cognitive performance in typically developing children. We hypothesized that older children and children with high attentional scores would have higher parietal alpha activity and frontal theta activity while at rest compared to young children and those with lower attentional scores. MEG data were collected in 65 typically developing children, ages 9–14 years, as part of the Developmental Chronnecto-Genomics study. Resting-state data were collected during eyes open and eyes closed for 5 min. Participants completed the NIH Toolbox Flanker Inhibitory Control (FICA) and Attention Test and Dimensional Change Card Sort Test (DCCS) to assess top-down attentional control. Spectral power density was used to characterize the FPN. We found during eyes open and eyes closed, all participants had higher theta and alpha power in parietal regions relative to frontal regions. The group with high attentional scores had higher alpha power during resting-state eyes closed compared to those with low attentional scores. However, there were no significant differences between age groups, suggesting changes in the maturation of neural oscillations in theta and alpha are not evident among children in the 9-14-year age range.
•Alpha power is associated with neuropsychological performance on attention tasks.•Theta and alpha power are greater in parietal regions relative to frontal regions.•Children with high resting alpha power also scored high in the attentional task.•Low variation in alpha reactivity across age and attentional ability.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Results are given for a study of the catalytic and physicochemical properties of monometallic Cu/CeO
2
-Al
2
O
3
and bimetallic Pd-Cu/CeO
2
-Al
2
O
3
catalysts for the synthesis of methanol from ...hydrogen and carbon dioxide. The catalytic activity was determined in methanol synthesis in a gradientless reactor at 200°C and 3.5 MPa. The physicochemical properties of these catalytic systems were studied by the BET method (Brunauer−Emmett− Teller method), temperature-programmed reduction of hydrogen (TPR-H
2
), temperature-programmed desorption of ammonia (TPD-NH
3
), x-ray diffraction (XRD), and Fourier-transform IR spectroscopy (FTIR). Our results showed high activity for the palladium-promoted catalyst, which is attributed to a synergistic effect between palladium and copper as well as the formation of a PdCu alloy during activation of this bimetallic catalyst in a reducing atmosphere of 5% H
2
95% Ar.
Full text
Available for:
DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
PDF
