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.