Augmentation of perivascular space visualization in basal ganglia and white matter hyperintensity lesion is a meaningful finding for subsequent cognitive decline.

BACKGROUND: Cerebral small vessel disease (CSVD) causes cognitive decline and perivascular space enlargement is one of the image markers for CSVD. PURPOSE: To search for clinical significance in the time-course augmentation of perivascular space in basal ganglia (BG-PVS) for cognitive decline. MATERIAL AND METHODS: This study population included 179 participants from a community-based cohort, aged 70 years at baseline. They had undergone magnetic resonance imaging (MRI) studies two or three times between 2000 and 2008. Based on the severity of BG-PVS or white matter hyperintensity lesions (WMHL) in 2000, the participants were divided into low-grade or high-grade groups, respectively. In addition, their time-course augmentation was evaluated, and we created a categorical BG-PVS WMHL change score based on their augmentation (1 = neither, 2 = BG-PVS augmentation only, 3 = WMHL augmentation only, 4 = both). Cognitive function was assessed based on the Mini-Mental State Examination (MMSE); the change was defined as the difference between scores in 2000 and 2008. We used simple or multiple regression analysis for MMSE score change according to MRI findings and clinical characteristics that were probably related to cognitive decline. RESULTS: In univariate analysis, MMSE score change was negatively associated with BG-PVS high grade at baseline and BG-PVS WMHL change score 4; this remained significant in multivariate analysis. In the final model based on the Akaike Information Criterion, BG-PVS WMHL change score 4 was associated with a 3.3-point decline in subsequent MMSE score. CONCLUSIONS: This study suggested that augmentation in both BG-PVS and WMHL was associated with subsequent cognitive decline.

Enhancing photocatalytic activity of LaTiO2N by removal of surface reconstruction layer.

LaTiO2N is an oxynitride photocatalyst that has ability to generate H2 and O2 from water under irradiation of light with wavelengths up to 600 nm. However, LaTiO2N necessitates sacrificial reagents that capture either photoexcited electrons or holes efficiently to be active in the photocatalytic reactions because of a considerable number of defects that cause trapping and recombination of photoexcited carriers. Therefore, identifying defect structures of LaTiO2N is important. In this study, using atomic-resolution scanning transmission electron microscopy, we evidence that eliminating defective surface reconstructed layers of LaTiO2N particles by the treatment with aqua regia can double the photocatalytic activity.

The time-course augmentation of perivascular space enlargement in the basal ganglia among a community-dwelling elder population.

PURPOSE: We examined whether time-course augmentation of perivascular space enlargement in the basal ganglia (BG-PVS) reflected cerebral small vessel disease (CSVD) severity by considering white matter hyperintensity lesion (WMHL) as an indicator for CSVD. MATERIALS AND METHODS: This study population included 416 older participants from a community-based cohort. They participated in magnetic resonance imaging (MRI) studies more than once during the study period. The grades for BG-PVS and WMHL were evaluated by visual rating scales; BG-PVS time-course augmentation in 4-9 years was also evaluated. At baseline, the participants were asked about their smoking and drinking history, and medical history. They also underwent a blood examination and their office blood pressure (BP) examination. In addition, 24-h ambulatory BP monitoring was also performed within the study period. RESULTS: Of the 416 participants, 48 participants (11.5%) had BG-PVS time-course augmentation. The participants with BG-PVS augmentation had significantly lower LDL levels, hyper-nighttime BP, and lower nighttime BP fall in univariate analysis (p = 0.03, p = 0.03, p = 0.003, respectively). In multivariate analysis, lower nighttime BP fall and male sex showed significance (p = 0.02, 0.03, respectively). Additionally, BG-PVS time-course augmentation was significantly associated with subsequent WMHL severity in univariate analysis (p < 0.001), which remained significant in multivariate analysis adjusted by imaging and demographic factors (p = 0.03). In multivariate analysis, additionally adjusted by the clinical factors, the significance disappeared (p = 0.07). CONCLUSION: This study revealed that the lower nighttime BP fall in ambulatory blood pressure monitoring was a factor significantly associated with BG-PVS augmentation. Moreover, the BG-PVS time-course augmentation would be a notable finding that was associated with the subsequent WMHL.

Enhanced water oxidation on Ta3N5 photocatalysts by modification with alkaline metal salts.

Tantalum nitride (Ta(3)N(5)) is a promising nitride semiconductor photocatalyst for solar water splitting because it has band edge potentials capable of producing hydrogen and oxygen from water under visible light (λ < 590 nm). However, the photocatalytic performance of Ta(3)N(5) has been far below expectations because insufficient crystallization upon thermal nitridation of the oxide precursors enhances undesirable charge recombination limiting the quantum efficiency of the photocatalytic reaction. This problem was successfully rectified in this study by modifying the surface of the starting Ta(2)O(5) with a small amount of alkaline metal (AM) salts. Compared with conventional Ta(3)N(5), Ta(3)N(5) nitrided from AM salt-modified Ta(2)O(5) had better crystallinity and smaller particles with smoother surfaces and, most importantly, demonstrated a 6-fold improvement in photocatalytic activity for O(2) evolution under visible light. AM salt modification was compatible with the loading of an O(2) evolution cocatalyst, such as CoO(x), yielding an apparent quantum efficiency of 5.2% at 500-600 nm. This indicates that the effects of AM modification were attributable to the changes in the crystallinity and the morphology of Ta(3)N(5) rather than to catalytic effects. Detailed characterization of the Na(2)CO(3)-modified Ta(3)N(5) suggested partial dissolution of Ta(2)O(5) and nucleation of NaTaO(3) in the early stages of nitridation, which gave rise to the characteristic particle morphologies and improved the crystallinity of the nitridation products. This study demonstrates that a facile pretreatment of a starting material can improve the physical and photocatalytic properties of photocatalysts drastically, enabling the development of advanced photocatalysts for solar water splitting.

Cobalt-modified porous single-crystalline LaTiO2N for highly efficient water oxidation under visible light.

Highly efficient water oxidation utilizing visible photons of up to 600 nm is a crucial step in artificial photosynthesis. Here we present a highly active photocatalyst for visible-light-driven water oxidation, consisting of single-crystalline meso- and macroporous LaTiO(2)N (LTON) with a band gap of 2.1 eV, and earth-abundasnt cobalt oxide (CoO(x)) as a cocatalyst. The optimized CoO(x)/LTON had a high quantum efficiency of 27.1 ± 2.6% at 440 nm, which substantially exceeds the values reported for previous particulate photocatalysts with a 600-nm absorption edge.

High temperature end of the so-called "Koga line": anomalies in temperature derivatives of heat capacities.

The so-called "Koga line" is a collection of the loci of anomalies in various third derivatives of the Gibbs function, G, in the temperature-mole fraction field for aqueous solutions of nonelectrolytes. This splits the H(2)O-rich region into two, in each of which the molecular organization and interactions we call it mixing scheme is qualitatively different. In this work, we attempt to locate the high temperature end of the Koga line. This is a particularly interesting range of the boundary, since its extrapolation to zero solute concentration provides information on possible temperature induced changes in the properties of pure water. To this end, we determine semi-isobaric heat capacities of aqueous 2-butoxyethanol by adiabatic calorimetry up to a maximum of 95 degrees C. The corrections due to vaporization were not applied due to the lack of required vapor pressure and thermal expansivity data. Furthermore, we measured directly the isobaric heat capacities per molar volume for aqueous 1-propanol as well as 2-butoxyethanol by differential scanning calorimetry up to 120 degrees C at 3 atm. We then took one more temperature derivative of the respective heat capacity data. The resulting third derivative quantities from the former data showed step-type anomalies, while those from the latter negative peak-type anomalies. The loci of these anomalous points seem to point to about 70 degrees C at infinite dilution.

Investigation on nitridation processes of Sr2Nb2O7 and SrNbO3 to SrNbO2N for photoelectrochemical water splitting.

The processes involved in the nitridation of Sr2Nb2O7 and SrNbO3 to SrNbO2N were assessed by varying the nitridation time, and the related effects on the physical and photoelectrochemical properties of the nitrided products were investigated. In the case of the layered perovskite-type oxide Sr2Nb2O7, the introduction of nitrogen and the extraction of oxygen took place concurrently, leading to lattice shrinkage and a porous structure. In contrast, during nitridation of the perovskite-type oxide SrNbO3, nitrogen was initially introduced without any loss of oxygen, which caused phase separation as a result of a lattice expansion and a charge compensation. The photoelectrochemical properties of obtained SrNbO2N under simulated sunlight were found to vary with the oxide precursor used and with the nitridation process.

Site-selective photodeposition of Pt on a particulate Sc-La5Ti2CuS5O7 photocathode: evidence for one-dimensional charge transfer.

Photodeposition of Pt on the Sc-doped La5Ti2CuS5O7 (Sc-LTC) photocathode, a visible-light-responsive semiconducting oxysulfide, is accomplished in a solution containing H2PtCl6 and K2C2O4. Pt particles are selectively deposited on the top surface of rod-like Sc-LTC particles as a result of one-dimensional transfer of photogenerated electrons.

Photoanodic and photocathodic behaviour of La5Ti2CuS5O7 electrodes in the water splitting reaction.

The particulate semiconductor La5Ti2CuS5O7 (LTC) with a band gap energy of 1.9 eV functioned as either a photocathode or a photoanode when embedded onto Au or Ti metal layers, respectively. By applying an LTC/Au photocathode and LTC/Ti photoanode to, respectively, photoelectrochemical (PEC) water reduction and oxidation concurrently, zero-bias overall water splitting was accomplished under visible light irradiation. The band structures of LTC/Au and LTC/Ti calculated using a semiconductor device simulator (AFORS-HET) confirmed the critical role of the solid/solid junction of the metal back contact in the charge separation and PEC properties of LTC photoelectrodes. The prominently long lifetime of photoexcited charge carriers in LTC, confirmed by transient absorption spectroscopy, allowed the utilization of both photoexcited electrons and holes depending on the band structure at the solid/solid junction.

The effects of preparation conditions for a BaNbO2 N photocatalyst on its physical properties.

BaNbO2 N is a semiconductor photocatalyst active for water oxidation under visible-light irradiation up to λ=740 nm. It is important to understand the nitridation processes of precursor materials to form BaNbO2 N to tune the physical properties and improve the photocatalytic activity. Comprehensive experiments and analyses of temperatures, durations, ammonia flow rates, and barium/niobium ratios in the precursor during the nitridation process reveals that faster ammonia flow rates and higher barium/niobium ratios in the precursors help to suppress reduction of pentavalent niobium ions in the nitridation products and that the use of a precursor prepared by a soft-chemistry route allows the production of BaNbO2 N at lower temperatures in shorter times than the use of physical mixtures of BaCO3 and Nb2 O5 because the niobium species is dispersed among the barium species. BaNbO2 N prepared by the soft-chemistry route exhibits comparatively higher activity than that prepared from physical mixtures of BaCO3 and Nb2 O5 , probably because of lower nitridation temperatures, which suppress excessive dissociation of ammonia, and thereby reduce pentavalent niobium ions, and intimate interaction of niobium and barium sources, which lowers the densities of mid-gap states associated with defects.

Specific-heat anomaly caused by ferroelectric nanoregions in Pb(Mg(1/3)Nb(2/3))O3 and Pb(Mg(1/3)Ta(2/3))O3 relaxors.

The specific heat of typical relaxors, Pb(Mg(1/3)Nb(2/3))O3 (PMN) and Pb(Mg(1/3)Ta(2/3))O3 (PMT), was measured by adiabatic and relaxation methods between 2 and 420 K. A broad anomaly was found in the specific heat curve over the wide temperature range between 150 and 500 K for PMN, and between 50 and 400 K for PMT, which provides evidence for the formation of ferroelectric nanoregions (FNR) in the paraelectric matrix. The entropy of the anomaly was estimated as 3.3 J K(-1) mol(-1) and 2.9 J K(-1) mol(-1) for PMN and PMT, respectively, which implies an order-disorder-type mechanism for the formation of FNR.