Factors governing the protonation of Keggin-type polyoxometalates: influence of the core structure in clusters

Atomic substitution is a promising approach for controlling structures and properties for developing clusters with desired responses. Although many possible coordination candidates could be deduced for substitution, not all can be prepared. Therefore, predicting the correlation between structures and physical properties is important prior to synthesis. In this study, regarding Keggin-type polyoxometalates (POMs) as a model cluster, the dominant factors affecting the protonation were investigated by atomic substitutions and geometry changes. The valence of Keggin-type POMs and the constituent elements of the cluster shell structure affect the charge and potential distribution, which change the protonation sites. Furthermore, the valence of Keggin-type POMs and the bond length between the core and shell structure determine the protonation energy. These factors also affect the HOMO-LUMO gap, which governs photochemical and redox reactions. These governing factors derived from actual parameters of the α-isomer of Keggin-type POMs enabled us to deduce the protonation energy of the β-isomer, which is more difficult to prepare and isolate than the α-isomer.

Efficient reverse water gas shift reaction at low temperatures over an iron supported catalyst under an electric field

The development of high-performance Fe-based catalysts is attractive because Fe is a cost-effective and earth-abundant element. Application of an external electric field and an appropriate catalytic support to an Fe-based catalyst enabled the reverse water-gas shift reaction to proceed with high activity, selectivity, and durability even at the low temperature of 423 K. The Fe-supported catalyst showed superior CO selectivity (≈ 100%) compared to the Co- or Ni-supported catalyst. The apparent activation energy (5.9 kJ mol-1) over the Fe/Ce0.4Al0.1Zr0.5O2 catalyst under an electric field was much lower than that without an electric field (61.4 kJ mol-1).

Vanadium-Containing Keggin-Type Polyoxometalates, [VM12O40]3- and [VVM11O40]4- (M = Mo, W): Structural Characterization and Voltammetric, NMR, and EPR Studies Related to Electrochemical Reduction at Framework and Central Vanadium Sites

Vanadium is accommodated in both the framework (VoutV) and central positions (VinV) in the Keggin-type polyoxometalates (POMs) [VinVVoutVM11O40]4- (M = Mo, W; VinVVoutVM11) and in the central position in [VinVM12O40]3- (VinVM12). The structures of the VinVVoutVM11 class have been determined by X-ray crystallography and compared to those of VinVM12 reported previously. A major feature of interest with POMs is their capacity for very extensive reduction, particularly when protonation accompanies the electron transfer step. With VinVVoutVM11 and VinVM12 POMs, knowledge as to whether reduction occurs at V or M sites and the concomitant dependence on acidity has been obtained. Frozen solution EPR spectra obtained following bulk electrolysis showed that the one-electron reduction of VinVMo12 occurs at the molybdenum framework site to give VinVMoVMo11. In contrast, EPR spectra of one-electron reduced VinVW12 at <30 K are consistent with the electron being accommodated on the central V atom in a tetrahedral environment to give VinIVW12. In the case of VinVVoutVM11, the initial reduction occurs at the framework VoutV site to give VinVVoutIVM11. The second electron is delocalized over the Mo framework in two-electron reduced VinVVoutIVMoVMo10, whereas it is accommodated on the central V site in VinIVVoutIVW11. The distance between VinIV and VoutIV in VinIVVoutIVW11 estimated as 3.5 ± 0.2 Å from analysis of the EPR spectrum is consistent with that obtained in VinVVoutVW11 from crystallographic data. Simulations of the cyclic voltammograms as a function of CF3SO3H acid concentration for the initial reduction processes provide excellent agreement with experimental data obtained in acetonitrile (0.10 M [n-Bu4N][PF6]) and allowed acid association constants to be estimated and compared with the literature values available for [XVoutVM11O40]n- (X = S (n = 3), P and As (n= 4); M = Mo, W). The interpretation of the voltammetric data is supported by 51V NMR measurements on the oxidized VV forms of the POMs.

Changes in Target Coverage and Dose to the Normal Brain during Fractionated Stereotactic Radiotherapy for Metastatic Brain Tumors

PURPOSE/OBJECTIVE(S)

Fractionated stereotactic radiotherapy (SRT) has been applied to large brain metastases to reduce the risk of radiation necrosis. For fractionated SRT, potential of interfractional tumor changes during the treatment period, such as tumor size, shape, and geometry, must be considered to improve the tumor local control. Our center performs adaptive re-planning for large brain metastases based on repeat MRI verification with a contrast agent in the middle of the treatment period. Purpose of this study is to evaluate the dosimetric impact of the changes in tumor size, shape, and geometry on the doses to the targets and normal brain in patients with brain metastases undergoing fractionated SRT.

MATERIALS/METHODS

Fifteen solitary large intracranial metastatic lesions treated with fractionated SRT were investigated. Standardized planning MRI (MRI-1) and repeat verification MRI (MRI-2) were performed during the middle of the irradiation period. The GTV on the MRI-1 and MRI-2 scans was contoured by the same oncologist. The PTV was created by adding an isotropic margin of 1 mm from the GTV in all directions. Volumetric modulated arc therapy (VMAT) with beam energies of 6 MV (flattening filter-free mode) was used and plans were normalized such that PTV D95% or D98% was equal to the prescribed dose. Beam configuration and intensity on the initial VMAT plan were used to evaluate the dose to the tumor and the normal brain on MRI-2. We evaluated the impact of D98% on the GTV using the plans on the MRI-1 and MRI-2 scans. For the normal brain, the V90%, V80%, and V50% were investigated.

RESULTS

The median GTV changed from 9.8 cc (range of 3.2-33.0 cc) to 9.7 cc (range of 2.8-36.5 cc) (p = 0.482). Three and four tumors exhibited volume shrinkage and enlargement changes of >10%. Five tumors exhibited volume shrinkage and enlargement changes of <10%. Three tumors showed no volume changes. Of the 15 large brain metastases, 12 tumors required treatment plan modification. The dosimetric parameters of the GTV, PTV, and normal brain did not significantly differ between the MRI-1 and MRI-2 scans. Regarding the tumor dose, the D98% to the GTV increased in patients with tumor shrinkage because of dose inhomogeneity and decreased in patients with tumor enlargement. The V90%, V80%, and V50% increase with decreasing tumor volumes and were linearly related to the tumor volume difference, with a coefficient of determination of 0.97, 0.98, and 0.97, respectively.

CONCLUSION

Our study demonstrated the usefulness of repeat verification MRI for adaptive radiotherapy in the middle of the treatment period due to changes in tumor size, shape, and geometry in patients with brain metastases. Repeated MRI should be considered to evaluate the dose to the target and normal brain, which improves tumor local control and reduces brain necrosis, to reduce the magnitude of underdosing to the target or overdosing to the normal brain during the treatment period.

Selective Electrochemical Hydrogenation of Phenol with Earth-abundant Ni-MoO2 Heterostructured Catalysts: Effect of Oxygen Vacancy on Product Selectivity

Herein, we report highly efficient carbon supported Ni-MoO₂ heterostructured catalysts for the electrochemical hydrogenation (ECH) of phenol in 0.10 M aqueous sulfuric acid (pH 0.7) at 60 °C. Highest yields for cyclohexanol and cyclohexanone of 95 % and 86 % with faradaic efficiencies of ∼50 % are obtained with catalysts bearing high and low densities of oxygen vacancy (O_v ) sites, respectively. In situ diffuse reflectance infrared spectroscopy and density functional theory calculations reveal that the enhanced phenol adsorption strength is responsible for the superior catalytic efficiency. Furthermore, 1-cyclohexene-1-ol is an important intermediate. Its hydrogenation route and hence the final product are affected by the O_v density. This work opens a promising avenue to the rational design of advanced electrocatalysts for the upgrading of phenolic compounds.

Cation effect on the electrochemical reduction of polyoxometalates in room temperature ionic liquids

Polyoxometalates (POMs) are compounds that undergo multiple successive one-electron redox transitions, making them convenient model reactants to study ion solvation effects. Room temperature ionic liquids (RTILs) are solvents made entirely of ions, and are expected to have interactions with the highly negatively charged POM reduction products. In this work, 12 RTILs with a range of different anions ([FSI]−=bis(fluorosulfonyl)imide, [TFSI]−=bis(trifluoromethylsulfonyl)imide, [BETI]−=bis(pentafluoroethylsulfonyl)imide, [BF4]−, [PF6]−) and cations (imidazolium, pyrrolidinium, sulfonium, ammonium, phosphonium) were employed as solvents to study the kinetics and thermodynamics of [S2W18O62]4− reduction, to shed light on solvation effects and ion-pairing effects caused by different RTIL structures. Up to six reversible reduction processes (producing highly negatively charged [S2W18O62]10−) were observed. For the RTILs that showed multiple processes, a clear trend in both the thermodynamics (inferred from the reduction peak potentials) and kinetics (inferred from the peak-to-peak separation) was observed, in the order: imidazolium < sulfonium ≈ ammonium < pyrrolidinium < phosphonium, supporting strong interactions of the negatively charged POM reduction products with the cation. Two related POMs, [P2W18O62]6− and [PW12O40]3−, were also studied in the optimum RTIL found for [S2W18O62]4− ([C2mim][FSI]=1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide), revealing fast kinetics and asymmetric peaks for [PW12O40]3−. This work demonstrates the importance of understanding the solvation effects of RTIL ions for highly charged electrogenerated products, allowing tuning of the RTIL structure to achieve the optimum kinetics and thermodynamics for an electrochemical process.

Derivation and validation of a machine learning-based risk prediction model for in-hospital mortality in patients with acute heart failure

Background

Although risk stratification is important in patients with acute heart failure (AHF) to predict patient prognosis, pre-existing risk models have not often been used due to its complexity. Recently, machine learning methods have been presented as an alternative approach to analyzing the predictive probability of large clinical datasets.

Purpose

The aim of this study is to develop a user-friendly risk score developed by one of machine learning methods and compare the performance of the new risk score to the existing conventional risk models.

Methods

A machine-learning-based risk model was developed using least absolute shrinkage and selection operator (LASSO) regression by identifying predictors of in-hospital mortality in the derivation cohort (REALITY-AHF) and externally validating and comparing its performance with two pre-existing risk models: the Get With The Guidelines risk score incorporating brain natriuretic peptide and hypochloremia (GWTG-BNP-Cl-RS) and the acute decompensated heart failure national registry (ADHERE) risk model.

Results

In-hospital deaths in the derivation and validation (NARA-HF) cohorts were 76 (5.1%) and 61 (4.9%), respectively. The risk score comprised four variables (systolic blood pressure, blood urea nitrogen, serum chloride, and C-reactive protein) and was developed according to the results of the LASSO regression weighting the coefficient for selected variables using a logistic regression model (4V-RS). Even though 4V-RS comprised fewer variables, In the validation cohort, it showed a higher area under the receiver operating characteristic curve (AUC) than the ADHERE risk model (AUC, 0.783 vs. 0.740; P=0.059) and a significant improvement in net reclassification (0.359; 95% CI, 0.10–0.67; p=0.006). 4V-RS performed similarly to GWTG-BNP-Cl-RS in terms of discrimination (AUC, 0.783 vs. 0.759; p=0.426) and net reclassification (0.176; 95% CI, −0.08–0.43; p=0.178).

Conclusions

The 4V-RS model comprising only four readily available data points at the time of admission performed similarly to the more complex pre-existing risk model in patients with AHF.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Cardiovascular Research Fund

Effect on Physical Functions of Older Adults When Refraining from Going out due to COVID-19 Restrictions

The study investigated the effect of refraining from going out during the coronavirus disease 2019 pandemic on physical function in community-dwelling older adults. The study included 49 patients who underwent home-visit rehabilitation. Four parameters of physical function—grip strength, five-times sit-to-stand test, single-leg stance test, and standing test for imbalance and disequilibrium (SIDE)—were assessed. They were evaluated before (March 2020) and after (May 2020) the state emergency was imposed, and the results were compared. The grip strength decreased significantly. A significant difference was also observed in the proportion of different SIDE levels in the study group before and after the implementation of the state emergency. The number of SIDE 2a or lower patients increased during the state emergency (p < 0.001). Comprehensive community support and rehabilitation are necessary to maintain physical function in older individuals. In particular, we believe that there is a need to utilize remote rehabilitation using digital devices (such as internet-based guidance) so that older adults can continue to exercise at home.

Ce(iv)-centered charge-neutral perovskite layers topochemically derived from anionic [CeTa2O7]- layers

Layered perovskites have been extensively investigated in many research fields, such as electronics, catalysis, optics, energy, and magnetics, because of the fascinating chemical properties that are generated by the specific structural features of perovskite frameworks. Furthermore, the interlayers of these structures can be chemically modified through ion exchange to form nanosheets. To further expand the modification of layered perovskites, we have demonstrated an advance in the new structural concept of layered perovskite "charge-neutral perovskite layers" by manipulating the perovskite layer itself. A charge-neutral perovskite layer in [CeIVTa2O7] was synthesized through a soft chemical oxidative reaction based on anionic [CeIIITa2O7]- layers. The Ce oxidation state for the charge-neutral [CeIVTa2O7] layers was found to be tetravalent by X-ray absorption fine structure (XAFS) analysis. The atomic arrangements were determined through scattering transmission electron microscopy and extended XAFS (EXAFS) analysis. The framework structure was simulated through density functional theory (DFT) calculations, the results of which were in good agreement with those of the EXAFS spectra quantitative analysis. The anionic [CeIIITa2O7]- layers exhibited optical absorption in the near infrared (NIR) region at approximately 1000 nm, whereas the level of NIR absorption decreased in the [CeIVTa2O7] charge-neutral layer due to the disappearance of the Ce 4f electrons. In addition, the chemical reactivity of the charge-neutral [CeIVTa2O7] layers was investigated by chemical reduction with ascorbic acid, resulting in the reduction of the [CeIVTa2O7] layers to form anionic [CeIIITa2O7]- layers. Furthermore, the anionic [CeIIITa2O7]- layers exhibited redox activity which the Ce in the perovskite unit can be electrochemically oxidized and reduced. The synthesis of the "charge-neutral" perovskite layer indicated that diverse features were generated by systematically tuning the electronic structure through the redox control of Ce; such diverse features have not been found in conventional layered perovskites. This study could demonstrate the potential for developing innovative, unique functional materials with perovskite structures.

Habitual exercise provides better prognosis for cardiac arrest with coronary artery disease

Background

Although regular physical activity has beneficial cardiovascular effects, exercise can trigger sudden cardiac arrest (SCA). Coronary artery disease (CAD) was identified as the most common cause of an exercise-related out-of-hospital cardiac arrest (OHCA). Regular exercise has been reported to reduce the risk of plaque rupture in animal studies and basic research. Therefore, we compared the coronary artery findings in CAD-OHCA patients with and without habitual exercise.

There have been few reports on whether regular exercise changes the prognosis in OHCA due to CAD (CAD-OHCA). We investigated the association between the better clinical outcome and the regular exercise in patients with CAD-OHCA.

Methods

This is a single-center retrospective analysis from 2006 to 2019. The consecutive 397 patients with OHCA due to myocardial ischemia underwent coronary angiography (CAG). After excluding 73 patients with vasospastic angina, the remaining 324 patients with CAD were enrolled in this study. We divided these patients into two groups according to whether they were habitually exercising (Exercise group: N=37) or not/unknown (Non-Exercise group: N=287).

Clinical outcome was a 30-day survival with minimal neurologic impairment represented by a Glasgow-Pittsburgh Cerebral Performance Categories Scale value 1 or 2.

Results

The patients in the Exercise Group were significantly younger (exercise vs. non-exercise, 57±12 vs. 64±12 years; P&lt;0.01) than those in the non-exercise group. The Exercise group had a lower incidence of diabetes mellitus (22% vs. 42%; P=0.02) and a higher incidence of dyslipidemia (81% vs. 62%; P=0.02) than the non-exercise group. The time from collapse to cardiopulmonary resuscitation (1.4±4.0 vs. 3.0±4.8min) and from collapse to return of spontaneous circulation (11.9±10.0 vs. 28.0±25.3min) were shorter in Exercise group (all p&lt;0.05). The ST-segment elevation was recorded on electrocardiography in fewer of the Exercise group (22% vs. 63%; P&lt;0.01). The finding of culprit lesion in the coronary arteries on arrival resulted significant differences between the 2groups (good collateral and/or TIMI3 flow: 62% vs. 25%, the plaque rupture and/or thrombus: 22% vs. 73%) (all p&lt;0.01) (Figure 1). Kaplan-Meier curve showed Exercise group has better neurological outcome at 30days compared than Non-Exercise (95% vs 51%; P&lt;0.001, log-rank test) (Figure 2). Multivariable Cox proportional hazards models revealed that a habitual exercise was one of the predictors of a good neurological outcome (HR 0.21, 95% CI 0.05–0.92; P=0.039).

Conclusions

The patients with habitual exercise had less plaque rupture, less coronary thrombosis than non-exercise. The patients with regular exercise had better clinical outcomes than non-exercise after CAD-OHCA.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Tokyo Metropolitan Goverment Figure 1. Findings of the culprit lesion in coronar arteriesFigure 2. Kaplan-Meier analysis

Polyoxometalates in Imidazolim-based Ionic Liquids: Acceptor Number and Polarity Estimated from Their Voltammetric Behaviour

The selection of an appropriate solvent is essential for achieving high yields and selectivity in chemical reactions. The chemical and physical parameters of organic solvents have been classified into several groups, and solvents can be compared with each other with respect to these properties. The acceptor number (A_N), donor number (D_N) and polarity (E_T^N) have been widely accepted and used for theoretically and quantitatively evaluating the properties of organic solvents. In a similar manner, the A_N, D_N and E_T^N of room temperature ionic liquids (RTILs) have been estimated from spectral changes in solvatochromic compounds. In this paper, the A_N and E_T^N of eight types of imidazolium-based RTILs were estimated from the relationship between the A_N and E_T^N values and the first redox potential obtained from the voltammograms of polyoxometalates (POMs) in various organic solvents. The obtained parameters were compared with those estimated by spectrophotometric methods reported previously by several groups. This new method for estimating the A_N and E_T^N of RTILs using the voltammetric behaviour of POMs with low charge density and high symmetry could provide the other path to obtain more reliable A_N and E_T^N of RTILs.

CMR feature tracking cloud assess right ventricular functional reserve with pulmonary arterial hypertension

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): JSPS KAKENHI, Grant-in-Aid for Early-Career Scientists.

Background

  Pulmonary arterial hypertension (PAH) remains a fatal disorder characterized by elevated pulmonary arterial pressure. Survival of the patients with PAH is determined from right ventricular (RV) function. CMR has become an attractive modality for following up and providing prognosis in such patients, and CMR feature tracking has been used as a newer useful parameter to assess RV function. However, it has not yet been determined whether CMR feature tracking can assess RV functional reserve in patients with PAH.

Purpose

We investigated whether CMR feature tracking can estimate RV functional reserve using a rat model with PAH.

Methods

 Rats were received injections with monocrotaline (MCT-rats, n = 19) or solvent (Ctr-rats, n = 5). Four weeks after the injections, we performed CMR on 7-T MRI scanner and imaged retrospective ECG-gated cine MR (16 phases/beat). RV ejection fraction (RVEF) and RV strain were analyzed before and after addition of 0.5∼3 nmol endothelin-1 (ET-1). After the measurements, we dissected trabeculae (length = 1.45 ± 0.07 mm, width = 334 ± 27 µm, thickness = 114 ± 6 µm) from the RVs of rat hearts. Trabeculae were electrically stimulated with 2-s intervals at extracellular Ca2+ of 0.7 and 2.0 mmol/L (24°C). Force and maximum dF/dt (dF/dtmax) were then measured using a silicon strain gauge in the absence and presence of 0.1 µM ET-1.

Results

 MCT-rats showed higher systolic RV pressure (RVP), lower RVEF, and lower RV global longitudinal strain (RVGLS) in CMR imaging and showed lower developed force and lower dF/dtmax in their trabeculae. Correlation between RVGLS and dF/dtmax was higher (r = 0.53, p &lt; 0.05) than that between RVEF and dF/dtmax (r = 0.24). In 5 MCT-rats with preserved RVEF (&gt;50%), RVGLS had already been reduced, suggesting that RVGLS is reduced earlier than RVEF. ET-1 increased developed force and dF/dtmax in trabeculae from MCT-rats (12.2 ± 5.7 to 17.4 ± 3.1 mN/mm2 and 0.08 ± 0.03 to 0.14 ± 0.06 mN/mm2/sec, respectively, n = 6), and ET-1 also increased RVP in MCT-rats and Ctr-rats (49.0 ± 19.3 to 59.7 ± 16.8 mmHg in MCT-rats, n = 6, 17.3 ± 7.5 to 20.4 ± 7.8 mmHg in Ctr-rats, n = 2). According to RV global circumferential strain (RVGCS) and RVEF, we could divide MCT-rats into three groups as follows: MCT-rats with reduced-RVGCS (&gt; -20%)/preserved-RVEF (&gt; 50%), MCT-rats with increased-RVGCS (&lt; -30%)/preserved-RVEF and MCT-rats with reduced-RVGCS/reduced-RVEF. ET-1 reduced RVGCS in MCT-rats with reduced-RVGCS/preserved-RVEF, while ET-1 did not change RVGCS in MCT-rats with increased-RVGCS/preserved-RVEF. MCT-rats with reduced-RVGCS/reduced-RVEF died after injection of ET-1.  In Ctr-rats, ET-1 did not change RVGCS and RVEF.  These results suggest that RVGCS can be useful to assess RV functional reserve.

Conclusion

 CMR feature tracking can estimate RV functional reserve earlier and more accurately than RVEF in rats with PAH.  RV strain may become an important parameter to assess RV functional reserve in patients with PAH.

Prognostic impact of six versus eight cycles of standard regimen in patients with diffuse large B-cell lymphoma: propensity score-matching analysis

Background

R-CHOP-21 has been the standard treatment for diffuse large B-cell lymphoma (DLBCL), but there is a paucity of evidence focusing on the number of cycles of regimens.

Patients and methods

We conducted a retrospective study to compare the effectiveness of six cycles of standard regimens versus eight cycles for overall survival (OS) in DLBCL patients using propensity score matching, in consideration of relative dose intensity (RDI).

Results

A total of 685 patients with newly diagnosed DLBCL were identified in three institutions from 2007 to 2017. Patients treated using six cycles of standard regimens were matched by propensity scores with those treated using eight cycles. A 1 : 1 propensity score matching yielded 138 patient pairs. Eight cycles did not significantly improve OS in the conventional Cox proportional hazards model (hazard ratio 0.849, 95% confidence interval 0.453-1.588, P = 0.608). Restricted cubic spline Cox models for OS confirmed that the effect of the number of cycles was not modified by total average RDI, the International Prognostic Index, and age. Occurrence of adverse events did not differ between six and eight cycles.

Conclusion

Even considering the impact of RDI, six cycles of the initial standard regimen for DLBCL is not inferior to eight cycles.

•

The optimal number of cycles of standard regimens including R-CHOP-21 for newly diagnosed DLBCL has not been determined.

•

This study was conducted to verify whether six cycles or eight cycles of standard regimen improved the prognosis of DLBCL.

•

Propensity score matching and a Cox hazards model with restricted cubic spline were used in this study.

•

No survival benefit of eight cycles compared with six cycles was seen, even taking into account RDI.

•

Prognosis was no better with eight cycles of (R-)CHOP-21 or THP-COP-21 than with six cycles, after age and IPI modifications.

Polyoxometalates in Analytical Sciences

Polyoxometalates (POMs) have been used for spectrophotometric determinations of silicon and phosphorus under acidic conditions, referred to as the molybdenum yellow method and molybdenum blue method, respectively. Many POMs are redox active and exhibit fascinating but complicated voltammetric responses. These compounds can reversibly accommodate and release many electrons without exhibiting structural changes, implying that POMs can function as excellent mediators and can be applied to sensitive determination methods based on catalytic electrochemical reactions. In addition, some rare-earth-metal-incorporated POMs exhibit fluorescence, which enables sensitive determination by the enhancement and quenching of fluorescence intensities. In this review, various analytical applications of POMs are introduced, mainly focusing on papers published after 2000, except for the molybdenum yellow method and molybdenum blue method.

Right ventricular longitudinal strain with CMR can more accurately estimate right ventricular functional reserve in rats with pulmonary arterial hypertension

Background

Right ventricular (RV) function is an important prognostic factor in patients with pulmonary arterial hypertension (PAH). Recently, CMR has become an attractive modality for follow up and providing prognosis in the patients, and strain has been used as a newer parameter to assess contractile properties of ventricle. It has not yet been established, however, whether RV strain with CMR can estimate RV functional reserve in the patients with PAH.

Purpose

We focused on CMR imaging of RV, investigating whether RV longitudinal strain can estimate RV functional reserve using a rat model with PAH.

Method

Rats were given a subcutaneous injection of 60 mg/kg monocrotaline (MCT-rats) or solvent (Ctr-rats). Four weeks after the injection, 25% of MCT-rats died due to RV failure. In the survivors of MCT- (n=19) and Ctr-rats (n=5), retrospective ECG-gated cine MR (16 phases/beat) was imaged with a 7T scanner. Subsequently, we measured RV pressure (RVP) via right internal jugular vein and dissected trabeculae (length = 1.45±0.07 mm, width = 334±27 μm, thickness = 114±6 μm) from RVs. We calculated weight ratio of RV free wall to left ventricle (LV) by RV/(LV+septum). Trabeculae were electrically stimulated with 2-s stimulus intervals, and force was measured using a silicon strain gauge (0.7 mM extracellular Ca2+, 24°C). To determine contractile properties of RV muscle, dF/dt was calculated. Using CMR imaging, we measured RV ejection fraction (RVEF) and RV longitudinal strain (RVLS). To modulate RVP, we intravenously injected 5 nmol endothelin-1 (ET-1) and again measured RVEF and RVLS.

Results

MCT-rats showed higher systolic RVP (62.5±16.6 vs. 25.9±1.86 mmHg, p&lt;0.01) and higher weight ratio of RV (0.60±0.03 vs. 0.28±0.02, p&lt;0.05). In CMR imaging, MCT-rats showed lower RVEF (36.1±11.2 vs. 64.8±8.4%, p&lt;0.001) and lower RVLS (−18±9 vs. −30±1%, p&lt;0.05). In trabeculae from RVs, MCT-rats showed lower developed force and lower dF/dt (p&lt;0.01). Correlation between RVLS and dF/dt was higher (n=20, r=0.53, p&lt;0.05) than that between RVEF and dF/dt (r=0.24). In addition, RVLS and dF/dt had already been decreased in 5 MCT-rats with relatively preserved RVEF (&gt;50%), suggesting that RVLS decreases earlier than RVEF in MCT-rats. Ten minutes after the injection of ET-1, RVP was increased from 49.4±7.9 to 57.9±6.4 mmHg in MCT-rats (n=6). In MCT-rats with preserved RVEF and decreased RVLS, the increase in RVP chiefly decreased RVEF while it did not change RVLS and RVEF in Ctr-rats, meaning that RV functional reserve had been decreased in MCT-rats. In trabeculae, developed force and dF/dt were increased after the addition of 0.1 μM ET-1 in MCT- (n=11, p&lt;0.01) and Ctr-rats (n=4, p&lt;0.01).

Conclusion

These results suggest that in rats with PAH, RVLS obtained from CMR can estimate RV functional reserve earlier and more accurately than RVEF. Therefore, RV strain with CMR may become an important parameter to assess RV functional reserve in patients with PAH.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grant-in-Aid for Young Scientists

New layered perovskite family built from [CeTa2O7]- layers: coloring mechanism from unique multi-transitions

A Ce3+-based layered perovskite compound, Dion-Jacobson type RbCeTa2O7, has been discovered for the first time by introducing only a trivalent cerium ion to form [CeTa2O7]- layers. The unique green color was experimentally and theoretically ascribed to two charge transfer transitions of ligand-to-metal O2p → Ce4f and metal-to-metal Ce4f → Ta5d.

Impact of the Lithium Cation on the Voltammetry and Spectroscopy of [XVM11O40]n- (X = P, As (n = 4), S (n = 3); M = Mo, W): Influence of Charge and Addenda and Hetero Atoms

Polyoxometalates (POMs) have been proposed as electromaterials for lithium-based batteries because they provide access to multiple electron transfer reactions coupled to fast lithium ion transport processes and high stability over many redox cycles. Consequently, knowledge of reversible potentials and Li⁺ cation-POM anion interactions provides a strategic basis for their further development. In this study, detailed cyclic voltammetric studies of a series of [XV^VM₁₁O₄₀]^n- (XVM₁₁^n-) POMs (where X (heteroatom) = P (n = 4), As (n = 4), and S (n = 3) and M (addenda atom) = Mo, W) have been undertaken in CH₃CN in the presence of LiClO₄, with n-Bu₄NPF₆ also present when required to keep the ionic strength close to constant value of 0.1 M. An analysis of the data has allowed the impact of the POM charge, and addenda and hetero atoms on the reversible potentials and the interaction between Li⁺ and the oxidized XV^VM₁₁^n- and reduced XV^IVM₁₁^(n+1)- forms of the V^V/IV redox couple to be determined. The SV^V/IVM₁₁^3-/4- process is independent of the Li⁺ concentration, implying the absence of the association of this cation with either SV^VM₁₁^3- or SV^IVM₁₁^4- redox levels. However, lithium-ion association constants for both V^V and V^IV redox levels were obtained from a comparison of simulated and experimental cyclic voltammograms for the reduction of the more negatively charged XV^VM₁₁^4- (X = P, As; M = Mo, W), since the Li⁺ interaction with these more negatively charged POMs is much stronger. The interaction between Li⁺ and the oxidized, XV^VM₁₁^n-, and reduced, XV^IVM₁₁^(n+1)-, forms was also investigated by ⁵¹V NMR and EPR spectroscopy, respectively, and it was confirmed that, due to their lower charge density, SV^VM₁₁^3- and SV^IVM₁₁^4- interact significantly less strongly with the lithium ion than XV^VM₁₁^4- and XV^IVM₁₁^5- (X = P, As). The lithium-POM association constants are substantially smaller than the corresponding proton association constants reported previously, which is attributed to a smaller surface charge density. The much stronger impact of Li⁺ on the W^VI/V- and Mo^VI/V-based reductions that occur at more negative potentials than the V^V/IV process also has been qualitatively evaluated.

Search for η^{'} Bound Nuclei in the ^{12}C(γ,p) Reaction with Simultaneous Detection of Decay Products

We measured missing mass spectrum of the ^{12}C(γ,p) reaction for the first time in coincidence with potential decay products from η^{'} bound nuclei. We tagged an (η+p) pair associated with the η^{'}N→ηN process in a nucleus. After applying kinematical selections to reduce backgrounds, no signal events were observed in the bound-state region. An upper limit of the signal cross section in the opening angle cosθ_{lab}^{ηp}<-0.9 was obtained to be 2.2  nb/sr at the 90% confidence level. It is compared with theoretical cross sections, whose normalization ambiguity is suppressed by measuring a quasifree η^{'} production rate. Our results indicate a small branching fraction of the η^{'}N→ηN process and/or a shallow η^{'}-nucleus potential.

Metal-substituted tungstosulfates with Keggin structure: synthesis and characterization

Simple synthetic procedures for accessing novel metal-substituted tungstosulfates [SMW11O39]4- with Keggin-type structures were developed based on the reaction of metal ions (M = Mn2+, Co2+, Ni2+, and Cu2+) with lacunary tungstosulfate, [SW11O39]6-, which was obtained by treating [SW12O40]2- with a weak base in acetone. All metal-substituted tungstosulfates were characterized by elemental analysis, X-ray crystallography, ESI-MS, IR, Raman, UV-Vis and cyclic voltammetry analyses.

Quantitative Determination of the Effective Mn4+ Concentration in a Li2TiO3:Mn4+ Phosphor and Its Effect on the Photoluminescence Efficiency of Deep Red Emission

Obtaining highly efficient photoluminescence with Mn⁴⁺-activated phosphors, which have been extensively studied in diverse lighting devices, requires the precise control of the manganese valence states. However, this control is difficult to achieve because manganese ions can have various valence states ranging from divalent to heptavalent. Additionally, the concentrations of Mn ions in each valence state, especially the effective Mn⁴⁺ concentration, have never been quantitatively determined in a phosphor crystal lattice. The relationship between the effective Mn⁴⁺ concentration and the luminescence properties of Mn⁴⁺-activated phosphors is of current interest for improving the phosphor properties. In the present study, the effective Mn⁴⁺ concentration in Li₂TiO₃:Mn⁴⁺ (LTO:Mn) phosphors prepared by the sol-gel method with heating at various temperatures was quantitatively analyzed by X-ray absorption near-edge spectroscopy. Moreover, the effect of the existence of Mn²⁺, Mn³⁺, and Mn⁴⁺ ions on the photoluminescence efficiency was investigated. The effective Mn⁴⁺ concentration was found to be over 60% in all phosphor samples. The quantum efficiencies (QEs) of all LTO:Mn phosphors strongly depend on the effective Mn⁴⁺ concentration. In particular, the LTO:Mn phosphor prepared by heating at 800 °C (LTO:Mn@800) contained the highest effective Mn⁴⁺ concentration of 98.1% and exhibited the highest internal QE of 31.6%. The results of this work provide new and important insights for the development of Mn⁴⁺-activated phosphors with high efficiency.

Comparison of neurosensory devices in detecting cutaneous thresholds related to protective sensibility: A cross-sectional study in São Paulo, Brazil

AIMS

To quantify the static and moving cutaneous sensibility threshold of diabetic patients using a neurosensory device for quantitative pressure detection.

METHODS

Three hundred thirty-four (n = 334) patients with type 2 diabetes and no previous history of wounds on the feet were studied using the one- and two-point static (1SP;2 SP) and one- and two-point moving (1MP;2 MP) tests through the pressure-specified sensory device (PSSD) on the cutaneous territory of the dorsal first web, hallux pulp, and medial calcaneal. In addition, patients were evaluated using the Semmes-Weinstein monofilament (SWM) No. 5.07 and tuning fork (128 Hz), which were used as normality parameters to detect the loss of protective sensibility. The same examinations were used to assess the control group (228 nondiabetic).

RESULTS

Altered values were observed for the static and moving tests over the three studied nerve territories. In comparing the sensibility threshold between diabetic patients who were sensitive and nonsensitive to SWM 5.07, we observed that this filament is not the most indicated for identifying the loss of sensibility in these patients. The prevalence of patients at risk varied between 85 and 89%. The biochemical marker associated with these high rates was HbA1c (p = 0.02).

CONCLUSIONS

Numeric quantification of the pressure threshold allowed us to determine the functional deficit of nerve fibers. Our findings suggest that the neurosensory device should be used as an adjuvant tool to evaluate the degree of loss of sensation on the skin.

P5626The clinical impact of the angle of OCT detected irregular protrusion after primary PCI at the STEMI culprit lesions

Background and introduction

The percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS) shows worse clinical outcomes than that for stable angina. As the one of the reasons, a recent optical coherence tomography (OCT) registry showed that the presence of irregular protrusion (IP)after coronary stenting was the worse predictor of 1-year device-oriented clinical end points. However, the impact of the quantitative findings on IP has not been well investigated in ACS patients.

Aim

To investigate the clinical impact of the post stent OCT findings, especially IP, detected by OCT after coronary stenting in ACS patients.

Methods

Consecutive 256 ACS lesions treated with OCT-guided PCI in our Medical University Hospital from January 2013 to November 2016 was retrospectively analyzed. In 256 lesions, 173 lesions were enrolled which had ST-elevation acute myocardial infarction (STEMI) with the onset to recanalization time within 720 minutes. In 170 lesions, the OCT images were available. In OCT image, IP was detected in 140 lesions (82.3%). Quantitative analysis of IP in post-procedure OCT imaging was observed to identify the OCT predictors for clinical endpoint including cardiac death, target vessel revascularization ant stent thrombosis in 1 year after index PCI.

Result

In post-procedure OCT findings, stent edge dissection was detected in 32.4% of lesions. Incomplete stent apposition was detected in 74.1%. Maximum angle of irregular protrusion was 194±86 degree and the incidence of maximum IP angle >180 degree was 52.9%. Maximum height of IP was 0.26±0.11mm. Small minimal stent area, defined as a lesion with minimal stent area <5.0 mm2 in a drug-eluting stent or <5.6 mm2 in a bare metal stent, was observed in 32.4% of lesions. Maximum IP angle and that of >180degree was significantly associated with the clinical endpoint (p=0.0259 and 0.0429, respectively).

Conclusion

In STEMI patients, IP was frequently observed in post-procedure OCT imaging during primary PCI. The maximum angle of IP was significantly associated with the clinical end points. The prognostic impact of maximum IP angle in STEMI patient needs further investigations.

P3579Clinical characteristics of an intracoronary erosion and thrombus in patients with vasospastic angina

Background

Intracoronary erosion and thrombus are sometimes detected in patients with vasospastic angina (VSA) through intracoronary imaging modalities. However, the clinical characteristics of these intracoronary findings remain unclear. Therefore, we assessed the clinical and lesion characteristics of these intracoronary abnormalities in patients with VSA.

Methods

We included 48 patients with VSA who underwent coronary angiography (CAG), spasm provocation test (SPT), and coronary angioscopy (CAS). In all patients, acetylcholine was infused in the left and right coronary arteries. The vessels were classified into spastic vessels (SVs) and non-spastic vessels (NSVs) based on SPT results. SVs that could not be observed using CAS were excluded from the study. CAG and SPT findings were evaluated for the presence of atherosclerotic lesions (%stenosis <30%) and types of spasm (segmental or diffuse). Two experts examined the presence of an intracoronary erosion and thrombus on CAS. Other serious symptoms such as cold sweating or syncope were also assessed.

Results

Among the 48 patients, intracoronary erosion and thrombus were detected in 11 (23%) and 10 (21%) patients, respectively, and total intracoronary abnormalities were observed in 17 (35%) patients. Male sex (p<0.05), smoking (p<0.05), and presence of other serious symptoms (p<0.01) were associated with the presence of intracoronary abnormalities. The logistic regression analysis showed the presence of other serious symptoms to be the only factor associated with the presence of intracoronary abnormalities (p<0.05). In the lesion analyses, among the 72 vessels, intracoronary abnormalities were observed only in SVs (17/53, 33%) but not in NSVs (0/19, 0%, p<0.01). Among the 53 SVs, the presence of atherosclerotic lesions (p<0.05) and segmental spasm type (p<0.05) were found to be associated with the presence of intracoronary abnormalities.

Conclusions

Intracoronary erosion and thrombus were observed in approximately 35% of patients with VSA. Such intracoronary abnormalities may be partly affected by the forms of the coronary artery and coronary spasm, leading to the onset of serious symptoms of VSA.

Radio frequency alternating electromagnetic field enhanced tetraruthenium polyoxometalate electrocatalytic water oxidation

RF-enhanced electrocatalytic water oxidation by protonated tetraruthenium polyoxometalate.

Identification of patterns of factors preceding severe or life-threatening asthma exacerbations in a nationwide study

BACKGROUND

Reducing near-fatal asthma exacerbations is a critical problem in asthma management.

OBJECTIVES

To determine patterns of factors preceding asthma exacerbations in a real-world setting.

METHODS

In a nationwide prospective study of 190 patients who had experienced near-fatal asthma exacerbation, cluster analysis was performed using asthma symptoms over the 2-week period before admission.

RESULTS

Three distinct clusters of symptoms were defined employing the self-reporting of a visual analogue scale. Cluster A (42.1%): rapid worsening within 7.4 hours from moderate attack to admission, young to middle-aged patients with low Body mass index and tendency to depression who had stopped anti-asthma medications, smoked, and hypersensitive to environmental triggers and furred pets. Cluster B (40.0%): fairly rapid worsening within 48 hours, mostly middle-aged and older, relatively good inhaled corticosteroid (ICS) or ICS/long-acting beta-agonist (LABA) compliance, and low perception of dyspnea. Cluster C (17.9%): slow worsening over 10 days before admission, high perception of dyspnea, smokers, and chronic daily mild-moderate symptoms. There were no differences in overuse of short-acting beta-agonists, baseline asthma severity, or outcomes after admission for patients in these 3 clusters.

CONCLUSION

To reduce severe or life-threatening asthma exacerbation, personalized asthma management plans should be considered for each cluster. Improvement of ICS and ICS/LABA compliance and cessation of smoking are important in cluster A. To compensate for low perception of dyspnea, asthma monitoring of peak expiratory flow rate and/or exhaled nitric oxide would be useful for patients in cluster B. Avoidance of environmental triggers, increase usual therapy, or new anti-type 2 response-targeted therapies should be considered for cluster C.

Regulation of Perfusion Pressure during Cardiopulmonary bypass using Sevoflurane

In hypothermic cardiopulmonary bypass (CPB), various vasodilators are used to control the perfusion pressure. These agents, however, often decrease the pressure excessively, and the low perfusion pressure may persist until the end of CPB. In this study we evaluate the safety and characteristics of the regulation of perfusion pressure during CPB using a volatile anesthetic, sevoflurane which has an extremely low partition coefficient. Twenty adult patients who underwent cardiac surgery were studied. Sevoflurane was applied by a vaporizer inserted into the oxygenator gas supply line. Pump flows were fixed at 2.4 L/min/m2 during the hypothermic period. Sevoflurane concentration was adjusted to keep mean arterial pressure (MAP) between 40 and 70 mmHg during CPB. Hemodynamic and metabolic parameters were measured and compared to the group we previously treated with chlorpromazine. In all cases, MAP could be maintained adequately. In the sevoflurane group, systemic vascular resistance indices (SVRI) during the rewarming period and at the end of CPB were higher, and doses of norepinephrine needed at the end of CPB were significantly lower than in the chlorpromazine group. The regulation of perfusion pressure during CPB using sevoflurane was safe and could easily maintain adequate SVRI.