Inhibitory action of B-type natriuretic peptide on adrenocorticotropic hormone in patients with acute coronary syndrome.

In addition to the classical actions of hemodynamic regulation, natriuretic peptides (NPs) interact with various neurohumoral factors that are deeply involved in the pathophysiology of cardiovascular diseases. However, their effects on the hypothalamic-pituitary-adrenal (HPA) axis, which is activated under acute high-stress conditions in acute coronary syndrome (ACS), remain largely unknown. We investigated the impact of plasma B-type NP (BNP) on plasma adrenocorticotropic hormone (ACTH)-cortisol levels during the acute phase of ACS ischemic attacks. The study population included 436 consecutive patients with ACS for whom data were collected during emergency cardiac catheterization. Among them, biochemical data after acute-phase treatment were available in 320 cases, defined as the ACS-remission phase (ACS-rem). Multiple regression analyses revealed that plasma BNP levels were significantly negatively associated with plasma ACTH levels only during ACS attacks (P < 0.001), but not in ACS-rem, whereas plasma BNP levels were not significantly associated with plasma cortisol levels at any point. Accordingly, covariance structure analyses were performed to clarify the direct contribution of BNP to ACTH by excluding other confounding factors, confirming that BNP level was negatively correlated with ACTH level only during ACS attacks (ß = -0.152, P = 0.002), whereas BNP did not significantly affect ACTH in ACS-rem. In conclusion, despite the lack of a significant direct association with cortisol levels, BNP negatively regulated ACTH levels during the acute phase of an ACS attack in which the HPA axis ought to be activated. NP may alleviate the acute stress response induced by severe ischemic attacks in patients with ACS.NEW & NOTEWORTHY BNP negatively regulates ACTH during a severe ischemic attack of ACS in which hypothalamic-pituitary-adrenal axis ought to be activated, indicating an important role of natriuretic peptides as a mechanism of adaptation to acute critical stress conditions in humans.

Time-dependent changes in P2Y12 reaction unit values for predicting the different types of cardiovascular events in patients with ischemic heart disease.

Several studies have investigated the association between P2Y12 reaction unit (PRU) value and major adverse cardiovascular events (MACEs) in patients with ischemic heart disease, but there is no well-established consensus on the utility of PRU value. Furthermore, the optimal PRU cut-off value varied with studies. One reason may be that the endpoints and observation periods differed, depending on the study. This study aimed to investigate the optimal cut-off and predictive ability of the PRU value for predicting cardiovascular events, while considering different endpoints and observation periods. We surveyed a total of 338 patients receiving P2Y12 inhibitors and measured PRU during cardiac catheterization. Using time-dependent receiver operating characteristic analysis, we evaluated the cut-off and area under curve (AUC) of the PRU value for two MACEs (MACE ①: composite of death, myocardial infarction, stent thrombosis, and cerebral infarction; MACE ②: composite of MACE ① and target vessel revascularization) at 6, 12, 24 and 36 months after cardiac catheterization. MACE ① occurred in 18 cases and MACE ② in 32 cases. The PRU cut-off values at 6, 12, 24, and 36 months were 257, 238, 217, and 216, respectively, for MACE ① and 250, 238, 209, and 204, respectively, for MACE ②. The AUCs at 6, 12, 24, and 36 months were 0.753, 0.832, 0.718, and 0.717, respectively, for MACE ① and 0.724, 0.722, 0.664, and 0.682, respectively, for MACE ②. The optimal cut-off and predictive ability of PRU values for cardiovascular events varied depending on different endpoints and duration of the observation periods. A relatively high PRU value is effective for short-term event suppression, but a low value is required for long-term event suppression.

Effects of angiotensin receptor-neprilysin inhibitor on insulin resistance in patients with heart failure.

AIMS: Although the haemodynamic effects of angiotensin receptor-neprilysin inhibitor (ARNI) on patients with heart failure have been demonstrated, the effect on glucose metabolism has not been fully elucidated. We retrospectively investigated the effect of ARNI on abnormal glucose metabolism in patients with stable chronic heart failure using an additional structural equation model (SEM) analysis. METHODS: We analysed 34 patients who regularly visited to the outpatient department of our institute with heart failure from October 2021 and July 2022 and who were taking angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs). Seventeen patients switched from ACE inhibitors or ARBs to an ARNI (ARNI group), and the other 17 patients continued treatment with ACE inhibitors or ARBs (control group). RESULTS: At baseline, although the ARNI group included fewer patients with heart failure with preserved ejection fraction in comparison with the control group (P = 0.004), patients with heart failure with mildly reduced ejection fraction, and heart failure with reduced ejection fraction were mostly biased towards the ARNI group (although not statistically significant). The baseline insulin resistance in the ARNI group was already significantly higher in comparison with the control group [fasting blood insulin, 9.7 (7.4, 11.6) vs. 7.8 (5.2, 9.2) µU/mL, P = 0.033; homoeostasis model assessment of insulin resistance (HOMA-IR), 3.10 (1.95, 4.19) vs. 2.02 (1.56, 2.42), P = 0.014]. Three months later, the fasting blood insulin and the HOMA-IR levels were both found to have decreased in comparison with the baseline values [baseline to 3 months: insulin, 9.7 (7.4, 11.6) to 7.3 (4.6, 9.4) µU/mL, P < 0.001; HOMA-IR, 3.10 (1.95, 4.19) to 1.96 (1.23, 3.09), P < 0.001]. An additional SEM analysis demonstrated that the initiation of ARNI had caused a reduction in the fasting blood insulin and the HOMA-IR levels at 3 months independently of the baseline fasting blood insulin and HOMA-IR levels, respectively. Similarly, the initiation of ARNI resulted in a significant reduction in serum uric acid levels (6.28 ± 0.35 to 5.80 ± 0.30 mg/dL, P = 0.008). CONCLUSIONS: In conclusion, even in a short period of only 3 months, the administration of ARNI improved insulin resistance and consequently reduced the serum uric acid levels in patients with stable chronic heart failure. Although the ARNI group already had high insulin resistance at baseline, an additional SEM analysis revealed that the decreased insulin resistance was truly due to the effect of ARNI.

Investigation of the small-balloon technique as a method for retrieving dislodged stents.

The small-balloon technique used to retrieve a dislodged coronary stent is less studied. We investigated the small-balloon technique to study the capture force and retrieval rate of dislodged proximal or distal stents. We developed a retrieval model for stent dislodgement and performed bench tests to compare proximal and distal capture. We evaluated capture force by capture site in a fixed stent dislodgement model and capture force and retrieval rate by capture site using a retrieval model of stent dislodgement. Three-dimensional (3D)-micro-computed tomography (CT) was used to scan the captured conditions of the distal (DC) and proximal (PC) groups. Stent, balloon shaft, and guiding catheter (GC) diameters were measured. Retrieval areas within GC were calculated and compared. The force was significantly lower in the PC group than in the DC group (p < 0.01). Successful retrieval was achieved in 100% and 84.8% in the PC and DC groups, respectively. The force required to retrieve the dislodged stent was significantly lower in the PC group than that in the DC group (p < 0.01). The force was significantly lower in the successful cases in the DC group than in the unsuccessful cases (p < 0.01). The retrievable areas in the PC and DC groups were 67.5% and 32.7%, respectively, as calculated from the values measured from the 3D-CT images. The success rate of PC was higher than that of DC using the small-balloon technique. The smaller proximal stent gap in the PC method facilitated the retrieval of the dislodgement stent.

Pulmonary Vein Angioplasty for Pulmonary Vein Stenosis After Ablation Therapy for Atrial Fibrillation　- A Report of 7 Cases.

BACKGROUND: Pulmonary vein (PV) stenosis after atrial fibrillation (AF) ablation is rare; however, it remains a serious complication. PV angioplasty is reportedly an effective therapy; however, a dedicated device for PV angioplasty has not been developed, and the detailed procedural methods remain undetermined. This study describes the symptoms, indications, treatment strategies, and long-term outcomes for PV stenosis after AF ablation.Methods and Results: This study retrospectively analyzed 7 patients with PV stenosis after catheter ablation for AF and who had undergone PV angioplasty at our hospital during 2015-2021. PV stenosis occurred in the left superior (5 patients) and left inferior (2 patients) PV. Six patients had hemoptysis, chest pain, and dyspnea. Seven de novo lesions were treated using balloon angioplasty (BA) (3 patients), a bare metal stent (BMS) (3 patients), and a drug-coated balloon (DCB) (1 patient). The restenosis rate was 42.9% (n=3; 2 patients in the BA group and 1 patient in the DCB group). The repeat treatment rate was 28.6% (2 patients in the BA group). Stenting was performed as repeat treatment. One patient with subsequent repeat restenosis development underwent BA. Ten PV angioplasties were performed; there were no major complications. CONCLUSIONS: Regarding PV angioplasty after ablation therapy for AF, stenting showed superior long-term PV patency than BA alone; therefore, it should be considered as a standard first-line approach.

Unique crosstalk between platelet and leukocyte counts during treatment for acute coronary syndrome: A retrospective observational study.

In the pathophysiology of acute coronary syndrome (ACS), platelet (PLT) and neutrophil (Neu) crosstalk may be important for activating coagulation and inflammation. It has been speculated that PLTs and Neu may affect each other's cell counts; however, few studies have investigated this hypothesis. In this study, we measured changes in blood cell counts in 245 patients with ACS during treatment and investigated the mutual effects of each blood cell type. Path diagrams were drawn using structural equation modeling, and temporal changes in the count of each blood cell type and the relevance of these changes were analyzed. Throughout the treatment period, the numbers of all blood cell types (red blood cells [RBCs], leukocytes, and PLTs) were associated with each other before and after treatment. A detailed examination of the different cell types revealed that the PLT count at admission had a significant positive effect on the leukocyte (especially Neu) count after treatment. Conversely, the leukocyte (especially Neu) count at admission had a significant positive effect on the PLT count after treatment. During ACS, PLTs and leukocytes, especially Neu, stimulate each other to increase their numbers. The formation of a PLT-leukocyte complex may increase coagulation activity and inflammation, which can lead to a further increase in the counts of both blood cell types.

A Pilot Evaluation Study of Diffuse Coronary Arterial Contraction Causing Ischemia by Double Measurement of Left Ventriculography Before and After Intracoronary Administration of Nitrates.

Background: Abnormal diffuse coronary artery contraction is not easily diagnosed. In order to evaluate its true risk, we performed double left ventriculography (LVG) before and after intracoronary administration of isosorbide dinitrate (ISDN). We also investigated the relationship between changes in coronary lumen area and changes in left ventricular ejection fraction (LVEF) after ISDN. Methods and Results: The study included 53 patients who underwent an acetylcholine (ACh) provocation test after coronary angiogram and LVG. The second LVG was performed after intracoronary ISDN administration. Coronary lumen area was measured by quantitative coronary arteriography (QCA). Simple and multiple regression analyses showed a significant correlation between changes in total QCA area before and after ISDN administration (pre-and post-total QCA area, respectively) and changes in LVEF. Using structural equation modeling, we observed a negative effect of pre-total QCA area and a positive effect of post-total QCA area on LVEF improvement. Importantly, LVEF improvement was similar between the ACh-positive and -negative groups on the coronary artery spasm test. Receiver operating characteristic curves indicated that the cut-off value at which changes in total QCA area affected changes in LVEF was 5%. Conclusions: Performing double LVG tests before and after ISDN administration may detect myocardial ischemia caused by diffuse coronary artery contraction. The addition of this method to the conventional ACh provocation test may detect the presence of local and/or global myocardial ischemia.

Close linkage between blood total ketone body levels and B-type natriuretic peptide levels in patients with cardiovascular disorders.

In patients with cardiovascular disorders, blood total ketone body (TKB) levels increase with worsening heart failure and are consumed as an alternative fuel to fatty acid and glucose. We investigated factors contributing to the increase in the blood TKB levels in patients with cardiovascular disorders. The study population consisted of 1030 consecutive patients who underwent cardiac catheterization. Covariance structure analyses were performed to clarify the direct contribution of hemodynamic parameters, including the left ventricular end-diastolic pressure (LVEDP), left ventricular end-systolic volume index (LVESVI), left ventricular end-diastolic volume index (LVEDVI), and B-type natriuretic peptide (BNP) levels, to TKB by excluding other confounding factors. These analyses showed that the TKB levels were significantly associated with the BNP level (P = 0.003) but not the LVEDP, LVESVI, or LVEDVI levels. This was clearly demonstrated on a two-dimensional contour line by Bayesian structure equation modeling. The TKB level was positively correlated with the BNP level, but not LVEDP, LVESVI or LVEDVI. These findings suggested that elevated blood TKB levels were more strongly stimulated by the increase in BNP than by hemodynamic deterioration. BNP might induce the elevation of TKB levels for use as an important alternative fuel in the failing heart.

Possible diverse contribution of coronary risk factors to left ventricular systolic and diastolic cavity sizes.

It is generally believed that risk factors damage the coronary arteries, cause myocardial ischemia, and consequently change the shape of the heart. On the other hand, each of the risk factors may also have a negative effect on the heart. However, it is very difficult to examine the effects of each of these risk factors independently. Therefore, it is necessary to select an appropriate statistical method and apply it efficiently. In this study, the effects of coronary risk factors on left ventricular size and cardiac function were investigated using structure equation modeling (SEM), and were shown as Bayesian SEM-based frequency polygons using selected two-dimensional contours. This study showed that each risk factor directly affected the shape of the heart. Because vascular risk and heart failure risk are likely to evolve at the same time, managing risk factors is very important in reducing the heart failure pandemic.

Possible Association Between Body Temperature and B-Type Natriuretic Peptide in Patients With Cardiovascular Diseases.

BACKGROUND: In addition to various biological effects of natriuretic peptides (NP) on cardiovascular systems, we recently reported that NP raises intracellular temperature in cultured adipocytes. We herein examined the possible thermogenic action of NP in consideration of hemodynamic parameters and inflammatory reaction by proposing structural equation models. METHODS AND RESULTS: The study population consisted of 1985 consecutive patients who underwent cardiac catheterization. Covariance structure analyses were performed to clarify the direct contribution of plasma B-type NP (BNP) to body temperature (BT) by excluding other confounding factors. A hierarchical path model showed increase in BNP, increase in C-reactive protein and decrease in left ventricular ejection fraction were mutually associated. As expected, C-reactive protein was positively correlated with BT. Importantly, despite a negative correlation between BNP and left ventricular ejection fraction, a decrease in the left ventricular ejection fraction was associated with BT decrease, whereas elevation in BNP level was associated with BT increase independently of C-reactive protein level (P = .007). CONCLUSIONS: Patients with LV dysfunction tend to manifest a decrease in BT, whereas BNP elevation is associated with an increase in BT independently of inflammatory response. These findings suggest the adaptive heat-retaining property of NP (and/or NP-associated factors) when BT falls owing to unfavorable hemodynamic conditions in a state of impaired cardiac function.

A Highly-sensitized Response of B-type Natriuretic Peptide to Cardiac Ischaemia Quantified by Intracoronary Pressure Measurements.

B-type natriuretic peptide (BNP) secretion is stimulated by cardiac dysfunction. However, it is unclear how finely myocardial ischaemia contributes to BNP secretion and whether increases in BNP secretion contribute to coronary vasodilation. This study investigated the direct interaction between plasma BNP levels and cardiac ischaemia using the baseline distal-to-aortic pressure ratio (Pd/Pa). We examined the baseline Pd/Pa and fractional flow reserve (FFR) in 167 patients with intermediate coronary stenosis. The plasma BNP level appeared to be associated with the baseline Pd/Pa in the study population, and this association appeared to become clear only in patients with an FFR ≤ 0.80. To examine the effect of the baseline Pd/Pa on the BNP level in these patients, structural equation modeling (SEM) was performed. The baseline Pd/Pa significantly affected the BNP level (ß: -0.37, p = 0.003) and the left ventricular ejection fraction (ß: 0.43, p = 0.001). To examine the role of BNP in coronary vasodilation, we proposed another path model using a novel value obtained by dividing the FFR by the baseline Pd/Pa (FFR/baseline Pd/Pa) as an index of the hyperaemic response. The BNP level significantly affected the FFR/baseline Pd/Pa (ß: 0.48, p = 0.037). This study demonstrated that BNP finely responded to an exacerbation of cardiac ischaemia and that increases in BNP secretion effectively ameliorated coronary vasoconstriction.

Non-contact acquisition of brain function using a time-extracted compact camera.

A revolution in functional brain imaging techniques is in progress in the field of neurosciences. Optical imaging techniques, such as high-density diffuse optical tomography (HD-DOT), in which source-detector pairs of probes are placed on subjects' heads, provide better portability than conventional functional magnetic resonance imaging (fMRI) equipment. However, these techniques remain costly and can only acquire images at up to a few measurements per square centimetre, even when multiple detector probes are employed. In this study, we demonstrate functional brain imaging using a compact and affordable setup that employs nanosecond-order pulsed ordinary laser diodes and a time-extracted image sensor with superimposition capture of scattered components. Our technique can simply and easily attain a high density of measurement points without requiring probes to be attached, and can directly capture two-dimensional functional brain images. We have demonstrated brain activity imaging using a phantom that mimics the optical properties of an adult human head, and with a human subject, have measured cognitive brain activation while the subject is solving simple arithmetical tasks.

Collaborative Activities of Noradrenaline and Natriuretic Peptide for Glucose Utilization in Patients with Acute Coronary Syndrome.

Glucose is an important preferential substrate for energy metabolism during acute coronary syndrome (ACS) attack, although insulin resistance (IR) increases during ACS. Increasing evidence indicates that natriuretic peptides (NP) regulate glucose homeostasis. We investigated possible compensatory actions of NP in collaboration with other neurohumoral factors that facilitate glucose utilization during ACS. The study population consisted of 1072 consecutive cases with ischemic heart disease who underwent cardiac catheterization (ACS, n = 216; non-ACS, n = 856). Among ACS subjects, biochemical data after acute-phase treatment were available in 91 cases, defined as ACS-remission phase (ACS-rem). Path models based on covariance structure analyses were proposed to clarify the direct contribution of B-type NP (BNP) and noradrenaline to glucose and HOMA-IR levels while eliminating confounding biases. In non-ACS and ACS-rem subjects, although noradrenaline slightly increased glucose and/or HOMA-IR levels (P < 0.03), BNP did not significantly affect them. In contrast, in ACS subjects, high noradrenaline was a significant cause of increases in glucose and HOMA-IR levels (P < 0.001), whereas high BNP was a significant cause of decreases in both parameters (P < 0.005). These findings indicate that BNP and noradrenaline coordinately activate glucose metabolism during ACS, with noradrenaline increasing glucose levels, as an energy substrate, while BNP improves IR and promotes glucose utilization.

Association between plasma B-type natriuretic peptide and anaemia in heart failure with or without ischaemic heart disease: a retrospective study.

OBJECTIVES: Anaemia is a risk of worsening heart failure. However, anaemia sometimes remains undetected because the superficial cardiac function does not precisely reflect the adverse impact of anaemia. Plasma B-type natriuretic peptide (BNP) could be helpful in these cases. However, the direct anaemic effects on BNP remain unknown. Herein, we compared the direct effect of anaemia on BNP and left ventricular ejection fraction (LVEF) using an advanced statistical procedure. DESIGN: A retrospective study. SETTING: Secondary care (cardiology), single-centre study. PARTICIPANTS: The study consisted of 3756 inpatients, including 684 without ischaemic heart disease (IHD) and 3072 with IHD. PRIMARY AND SECONDARY OUTCOME MEASURES: Relationship between plasma BNP levels and LVEF values. RESULTS: A path model was constructed to simultaneously examine the adverse impact of anaemia on LVEF and plasma BNP, allowing for renal function. The path model revealed that LVEF increased in response to low haemoglobin (Hb), and the phenomenon was prominent in non-IHD (standardised regression coefficients (St.ß): -0.264, p<0.001) rather than in IHD (St.ß: 0.015, p=0.531). However, the response of BNP was commonly observed in both groups (non-IHD St.ß: -0.238, IHD St.ß: -0.398, p<0.001, respectively). Additionally, this study showed a direct link between low estimated glomerular filtration rate and high BNP independently of LVEF. Incrementally, Bayesian structural equation modelling in covariance structure analysis clearly supported this result. The scatter plots and simple regression analysis revealed that an adequate blood supply was approximately Hb 110 g/L and over in the non-IHD patients, whereas blood was not supplied in sufficient quantities even by Hb 130 g/L in patients with IHD. CONCLUSION: The current study demonstrated that anaemia was a substantial risk for worsening cardiac overload as estimated by plasma BNP. The anaemic response of LVEF likely changed depending on underlying cardiac disorders (IHD or not). However, the response of BNP was robustly observed.

High Serum Uric Acid is Highly Associated with a Reduced Left Ventricular Ejection Fraction Rather than Increased Plasma B-type Natriuretic Peptide in Patients with Cardiovascular Diseases.

High serum uric acid (UA) has been reported to be associated with left ventricular (LV) dysfunction; however, the relationship between UA and plasma B-type natriuretic peptide (BNP), a sensitive biomarker of heart failure, is still unclear. This study investigated their relationship to provide an accurate assessment of high UA. The study patients consisted of 3,077 subjects who underwent cardiac catheterization because of various cardiovascular disorders. Since the explanatory factors of multiple regression analysis were mostly confounding with each other, subgroup analysis was performed by quartering the study population using the respective risk factors and by covariance structure analysis. This analysis revealed that UA was almost always well associated with a reduced LV ejection fraction (LVEF), but generally not with BNP. UA was significantly associated with BNP in lean aged females, but not in obese adolescent males, although LVEF was significantly reduced in response to a high UA in both groups. A high UA is a direct risk factor for cardiac dysfunction from the perspective of BNP; however, augmentation of BNP in response to a high UA would likely be restricted among obese adolescent males. On the other hand, the observed LV systolic dysfunction, such as LVEF, reflects a high UA on an almost constant basis.

A high performance catalyst of shape-specific ruthenium nanoparticles for production of primary amines by reductive amination of carbonyl compounds.

The creation of metal catalysts with highly active surfaces is pivotal to meeting the strong economic demand of the chemical industry. Specific flat-shaped pristine fcc ruthenium nanoparticles having a large fraction of atomically active {111} facets exposed on their flat surfaces have been developed that act as a highly selective and reusable heterogeneous catalyst for the production of various primary amines at exceedingly high reaction rates by the low temperature reductive amination of carbonyl compounds. The high performance of the catalyst is attributed to the large fraction of metallic Ru serving as active sites with weak electron donating ability that prevail on the surface exposed {111} facets of flat-shaped fcc Ru nanoparticles. This catalyst exhibits a highest turnover frequency (TOF) of ca. 1850 h-1 for a model reductive amination of biomass derived furfural to furfurylamine and provides a reaction rate approximately six times higher than that of an efficient and selective support catalyst of Ru-deposited Nb2O5 (TOF: ca. 310 h-1).

The beneficial effects of long-term enzyme replacement therapy on cardiac involvement in Japanese Fabry patients.

Fabry disease is a hereditary disorder that occurs due to the reduction or absence of alpha-galactosidase A activity, which leads to cardiac involvement including left ventricular hypertrophy (LVH). Enzyme replacement therapy (ERT) provides better patient outcomes by preventing serious complications. However, there have been very few studies on the long-term effects of ERT on the cardiac manifestations in Japanese Fabry patients. We retrospectively analyzed the data from the medical records of 42 Fabry patients (male, n = 17; female, n = 25) who were followed at Jikei University Hospital, and in whom the long-term effects of ERT could be evaluated (median follow-up period: male, 11 years; female, 8 years). The slope of the left ventricular mass (LVM) increase was 3.02 ±â€¯3.41 g/m2/year in males and 1.69 ±â€¯2.73 g/m2/year in females. In a subgroup analysis, the slopes of males with and without LVH did not differ to a statistically significant extent; however, the slope in female patients without LVH was significantly smaller than that of female patients with LVH. We then compared our data to the natural historical data that have previously been reported. In comparison to the previously reported data, we found a significant reduction in the LVM changes (g/height2.7/year) of patients who received long-term ERT (male, 4.07 ±â€¯1.03 to 1.25 ±â€¯1.39; female, 2.31 ±â€¯0.81 to 0.78 ±â€¯1.23). Long-term ERT effectively prevents LVH in Fabry patients. This effect was also observed in the patients with LVH prior to the initiation of ERT.

Large Oblate Hemispheroidal Ruthenium Particles Supported on Calcium Amide as Efficient Catalysts for Ammonia Decomposition.

Ammonia decomposition is an important technology for extracting hydrogen from ammonia toward the realization of a hydrogen economy. Herein, it is reported that large oblate hemispheroidal Ru particles on Ca(NH2 )2 function as efficient catalysts for ammonia decomposition. The turnover frequency of Ru/Ca(NH2 )2 increased by two orders of magnitude when the Ru particle size was increased from 1.5 to 8.4 nm. More than 90 % ammonia decomposition was achieved over Ru/Ca(NH2 )2 with large oblate hemispheroidal Ru particles at 360 °C, which is comparable to that of alkali-promoted Ru catalysts with small Ru particle sizes. XAFS analyses revealed that Ru particles are immobilized on Ca(NH2 )2 by Ru-N bonds formed at the metal/support interface, which lead to oblate hemispheroidal Ru particles. Such a strong metal-support interaction in Ru/Ca(NH2 )2 is also substantiated by DFT calculations. The high activity of Ru/Ca(NH2 )2 with large Ru particles primarily originates from the shape and appropriate size of the Ru particles with a high density of active sites rather than the electron-donating ability of Ca(NH2 )2 .

Self-organized Ruthenium-Barium Core-Shell Nanoparticles on a Mesoporous Calcium Amide Matrix for Efficient Low-Temperature Ammonia Synthesis.

A low-temperature ammonia synthesis process is required for on-site synthesis. Barium-doped calcium amide (Ba-Ca(NH2 )2 ) enhances the efficacy of ammonia synthesis mediated by Ru and Co by 2 orders of magnitude more than that of a conventional Ru catalyst at temperatures below 300 °C. Furthermore, the presented catalysts are superior to the wüstite-based Fe catalyst, which is known as a highly active industrial catalyst at low temperatures and pressures. Nanosized Ru-Ba core-shell structures are self-organized on the Ba-Ca(NH2 )2 support during H2 pretreatment, and the support material is simultaneously converted into a mesoporous structure with a high surface area (>100 m2 g-1 ). These self-organized nanostructures account for the high catalytic performance in low-temperature ammonia synthesis.

Conflicting relationship between age-dependent disorders, valvular heart disease and coronary artery disease by covariance structure analysis: Possible contribution of natriuretic peptide.

BACKGROUND: It is conceivable that contemporary valvular heart disease (VHD) is affected largely by an age-dependent atherosclerotic process, which is similar to that observed in coronary artery disease (CAD). However, a comorbid condition of VHD and CAD has not been precisely examined. The first objective of this study was to examine a possible comorbid condition. Provided that there is no comorbidity, the second objective was to search for the possible reasons by using conventional risk factors and plasma B-type natriuretic peptide (BNP) because BNP has a potentiality to suppress atherosclerotic development. METHODS: The study population consisted of 3,457 patients consecutively admitted to our institution. The possible comorbid condition of VHD and CAD and the factors that influence the comorbidity were examined by covariance structure analysis and multivariate analysis. RESULTS: The distribution of the patients with VHD and those with CAD in the histograms showed that the incidence of VHD and the severity of CAD rose with seniority in appearance. The real statistical analysis was planned by covariance structure analysis. The current path model revealed that aging was associated with VHD and CAD severity (P < 0.001 for each); however, as a notable result, there was an inverse association regarding the comorbid condition between VHD and CAD (Correlation coefficient [ß]: -0.121, P < 0.001). As the second objective, to clarify the factors leading to this inverse association, the contribution of conventional risk factors, such as age, gender, hypertension, smoking, diabetes, obesity and dyslipidemia, to VHD and CAD were examined by multivariate analysis. However, these factors did not exert an opposing effect on VHD and CAD, and the inverse association defied explanation. Since different pathological mechanisms may contribute to the formation of VHD and CAD, a differentially proposed path model using plasma BNP revealed that an increase in plasma BNP being drawn by VHD suppressed the progression of CAD (ß: -0.465, P < 0.001). CONCLUSIONS: The incidence of VHD and CAD showed a significant conflicting relationship. This result supported the likely presence of unknown diverse mechanisms on top of the common cascade of atherosclerosis. Among them, the continuous elevation of plasma BNP due to VHD might be one of the explicable factors suppressing the progression of CAD.