Correction: Band gap modification and photoluminescence enhancement of graphene nanoribbon filled single-walled carbon nanotubes.

Correction for 'Band gap modification and photoluminescence enhancement of graphene nanoribbon filled single-walled carbon nanotubes' by A. I. Chernov et al., Nanoscale, 2018, DOI: 10.1039/c7nr07054c.

Band gap modification and photoluminescence enhancement of graphene nanoribbon filled single-walled carbon nanotubes.

Molecule encapsulation inside the single-walled carbon nanotube (SWCNT) core has been demonstrated to be a successful route for the modification of nanotube properties. SWCNT diameter-dependent filling results in band gap modification together with the enhancement of photoluminescence quantum yield. However, the interaction between the inner structure and the outer shell is complex. It depends on the orientation of the molecules inside, the geometry of the host nanotube and on several other mechanisms determining the resulting properties of the hybrid nanosystem. In this work we study the influence of encapsulated graphene nanoribbons on the optical properties of the host single-walled carbon nanotubes. The interplay of strain and dielectric screening caused by the internal environment of the nanotube affects its band gap. The photoluminescence of the filled nanotubes becomes enhanced when the graphene nanoribbons are polymerized inside the SWCNTs at low temperatures. We show a gradual photoluminescence quenching together with a selective signal enhancement for exact nanotube geometries, specifically (14,6) and (13,8) species. A precise adjustment of the optical properties and an enhancement of the photoluminescence quantum yield upon filling for nanotubes with specific diameters were assigned to optimal organization of the inner structures.

Association of hypertension with small, dense low-density lipoprotein in patients without metabolic syndrome.

A higher proportion of small, dense low-density lipoprotein (sdLDL) is known to be associated with a high prevalence of cardiovascular disease in association with metabolic syndrome (MS). Hypertension (HTN) is one of the known risk factors for MS. However, whether HTN is associated with sdLDL in patients without MS is not yet clear. The lipid profiles, including low-density-lipoprotein (LDL) subfractions, of 383 consecutive subjects were evaluated. The patients without MS consisted of 198 hypertensive patients (non-MS/HTN group) and 108 normotensive subjects (non-MS/non-HTN group). The peak and mean particle diameter of LDL were measured by gradient gel electrophoresis. Plasma total cholesterol, LDL cholesterol, high-density lipoprotein (HDL) cholesterol, triglyceride (TG), HDL cholesterol/Apo A1, LDL-C/ApoB and Apo(A1, B, CII and E) levels did not differ between the non-MS/non-HTN and non-MS/HTN groups. When analyzing LDL subfraction, the absolute amount of patterns A and B was not different between the non-MS/non-HTN and non-MS/HTN groups. Compared with the non-MS/non-HTN groups, the proportion of sdLDL was higher in the non-MS/HTN group (37.7% versus 39.9%, P=0.046), but not significant after adjustment of waist circumference, serum TG, age and statin usage. The proportion of sdLDL to total LDL was higher in hypertensive subjects, even those without MS, than in normotensive subjects. However, this difference of LDL subfraction in hypertensive patients is associated with higher waist circumference, higher serum TG, older age and more statin usage. This result suggests that HTN may contribute to atherosclerosis and endothelial dysfunction with associated risk factors that influence LDL size.

Purity-enhanced bulk synthesis of thin single-wall carbon nanotubes using iron-copper catalysts.

We report high purity and high yield synthesis of single-wall carbon nanotubes (SWCNTs) of narrow diameter from iron-copper bimetal catalysts. The SWCNTs with diameter of 0.8-1.2 nm are synthesized using the zeolite-supported alcohol chemical vapour deposition method. Single metal and bimetal catalysts are systematically investigated to achieve both the enhancement of SWCNT yield and the suppression of the undesired formation of graphitic impurities. The relative yield and purity of SWCNTs are quantified using optical absorption spectroscopy with an ultracentrifuge-based purification technique. For the single metal catalyst, iron shows the highest catalytic activity compared with the other metals such as cobalt, nickel, molybdenum, copper, and platinum. It has been found that the addition of copper to iron results in the suppression of carbonaceous impurity formation without decreasing the SWCNT yield. The purity-enhanced SWCNT shows fairly low sheet resistance due to the improvement of inter-nanotube contacts. This scalable design of SWCNT synthesis with enhanced purity is therefore a promising tool for shaping future high performance devices.

Non-concurrent dosing attenuates the pharmacokinetic interaction between amlodipine and simvastatin.

OBJECTIVES: To explore if non-concurrent amlodipine dosing results in less drug interaction, the pharmacokinetic profiles, safety and efficacy endpoints were assessed following repeated doses of simvastatin, co-administered concurrently or non-concurrently with amlodipine in patients with coexisting hypertension and hyperlipidemia. METHODS: Seventeen patients randomly received daily doses of 20 mg simvastatin and 5 mg amlodipine for 6 weeks, either with both drugs at 7:00 PM (concurrent) or with simvastatin at 7:00 PM followed by amlodipine at 11:00 PM (non-concurrent). The maximum plasma concentration (Cmax) and the area under the concentration-time curve up to the last quantifiable concentration (AUClast) were estimated at steady state. Lipid profiles and blood pressure values were also compared between the concurrent and non-concurrent groups. RESULTS: The Cmax and AUClast and of simvastatin acid in the non-concurrent amlodipine dosing group were 63.2% and 66.0%, respectively, of the values obtained in the concurrent group (1.2 +/- 1.0 vs. 1.9 +/- 0.9 ng/ml and 10.3 +/- 8.3 vs. 15.6 +/- 7.5 h ng/ml, respectively, mean +/- standard deviation). Changes from baseline in lipid profile and blood pressure were comparable between the groups. CONCLUSIONS: Non-concurrent dosing may be a useful and safe therapeutic option for patients who require two or more drugs administered concomitantly, but who are likely to develop unwanted drug interactions.

Association of coronary artery calcification with obstructive sleep apnea and obesity in middle-aged men.

BACKGROUND AND AIMS: Obstructive sleep apnea (OSA) and obesity are closely associated, and both have been reported to increase the risk of coronary heart disease. Although obesity is known to be associated with coronary artery calcification (CAC), there is limited information on whether OSA is associated with CAC independent of obesity. METHODS AND RESULTS: A cross-sectional study examined the association between OSA and CAC among 258 healthy men, ages 40-49 years old, randomly selected from a population-based cohort. All individuals underwent overnight polysomnography and electron-beam computed tomography to measure their apnea-hypopnea index (AHI) and degree of CAC. A logistic regression model including potential cardiovascular risk factors excluding body mass index (BMI) showed that the presence of CAC was significantly greater in the fourth quartile versus the first quartile of AHI severity (odds ratio [OR] 2.21, 95% confidence interval [CI] 1.01-4.86). A multivariate linear regression model excluding BMI also showed that AHI was significantly associated with CAC (P = 0.004). However, this association was no longer significant after adjusting for BMI. CONCLUSIONS: In our cross-sectional study, even though both OSA and obesity were positively associated with the presence and extent of CAC, only obesity remained a significant independent contributor after an adjustment for potential cardiovascular risk factors, irrespective of OSA.

Impact of hypertension on coronary artery spasm as assessed with intracoronary acetylcholine provocation test.

Both hypertension and coronary artery spasm (CAS) are associated with endothelial dysfunction. Thus, a higher incidence of CAS is expected in hypertensive patients. We evaluated the impact of hypertension on CAS with intracoronary acetylcholine (ACh) provocation test. A total of 986 patients (685 hypertensive patients vs 301 normotensive patients) who underwent coronary angiography with ACh provocation test were enrolled. ACh was injected into the left coronary artery in incremental doses of 20, 50 and 100 microg min(-1). Significant CAS was defined as a transient >70% luminal narrowing with concurrent chest pain and/or ST-segment changes. Although the incidences of significant ACh-induced CAS were similar between hypertensive and normotensive patients (35.8 vs 39.2%, P=0.303), multivariate logistic analysis showed that hypertension was negatively associated with ACh-induced CAS (odds ratio: 0.70, 95% confidence interval: 0.51-0.94, P=0.020). The angiographic characteristics of ACh-induced CAS were similar between these two groups. Subgroup analysis regarding the impact of the status of blood pressure control on CAS showed that hypertensive patients with controlled blood pressure had a significantly higher incidence of CAS than those with uncontrolled blood pressure (45.2 vs 27.9%, P<0.001), and that uncontrolled blood pressure was negatively associated with ACh-induced CAS (odds ratio: 0.56, 95% confidence interval: 0.40-0.79, P=0.001). In conclusion, despite the expected endothelial dysfunction, hypertension and uncontrolled blood pressure are negatively associated with CAS, suggesting that the mechanisms and risk factors of CAS may be significantly different from those of coronary artery disease.

Relationship between blood pressure parameters and pulse wave velocity in normotensive and hypertensive subjects: invasive study.

Blood pressure (BP) is one of the most important contributing factors to pulse wave velocity (PWV), a classic measure of arterial stiffness. Although there have been many non-invasive studies to show the relation between arterial stiffness and BP, the results are controversial. The aim of this study is to evaluate the role of BP as an influencing factor on PWV using invasive method. We observed 174 normotensive and untreated hypertensive subjects using coronary angiography. Arterial stiffness was assessed through aorto-femoral PWV by foot-to-foot velocity method using fluid-filled system. And BP was measured by pressure wave at the right common femoral artery. From univariate analysis, age, diabetes mellitus (DM), hypertension, waist, waist-to-hip ratio, total cholesterol-to-high-density lipoprotein cholesterol ratio, systolic BP (SBP), pulse pressure (PP) and mean arterial pressure (MAP) showed significant association with PWV. To avoid multiple colinearity among SBP, PP and MAP, we performed multiple regression analysis predicting PWV thrice. Age, DM and each BP were significantly and consistently correlated to PWV. In the first and third modules, compared to age, SBP and MAP were less strong predictors, respectively. However, PP was the stronger predictor than age and DM in the second module. Lastly, we simultaneously forced MAP and PP with other variables in the fourth multivariate analysis. Age, DM and PP remained significantly correlated with PWV, but the significance of MAP was lost. This is the first invasive study to suggest that PP has the strongest correlation with PWV among a variety of BP parameters.

Assessment of coronary flow reserve with transthoracic Doppler echocardiography: comparison with intracoronary Doppler method.

To evaluate the feasibility and usefulness of transthoracic Doppler echocardiography (TTDE) as a non-invasive method in recording distal anterior descending (LAD) coronary flow velocity, we compared coronary flow reserve (CFR) measured by TTDE with measurements by intracoronary Doppler wire (ICDW). Twenty-one patients without LAD stenosis were studied. ICDW performed at baseline and after intracoronary injection of 18 microg adenosine. TTDE was performed at baseline and after intravenous adenosine (140 microg/kgmin for 2 min). Adequate Doppler recordings of coronary flow velocities during systole were obtained in 14 of 21 study patients (67%) and during diastole in 17 (81%) patients. Baseline and hyperemic peak diastolic flow velocities measured by TTDE were significantly smaller than those obtained by ICDW (p<0.05). However, diminishing trends of diastolic and systolic velocity ratio after hyperemia were similarly observed in both methods. CFR obtained by TTDE (3.0+/-0.5), was higher than the value calculated by ICDW (2.5+/-0.4). There were significant correlations between the values obtained by the two methods (r=0.72, p<0.01). It is concluded that TTDE is a feasible method in measuring coronary flow velocity and appears to be a promising non-invasive method in evaluating CFR.

Assessment of coronary flow reserve with transthoracic Doppler echocardiography: comparison among adenosine, standard-dose dipyridamole, and high-dose dipyridamole.

Coronary flow reserve (CFR), defined as a ratio of hyperemic-to-basal coronary flow velocity, provides important information about the functional aspect of coronary circulation. However, it usually is determined by invasive methods during catheterization. Recent studies have shown that transthoracic Doppler echocardiography (TTDE) may be useful in the measurement of coronary flow velocity in the distal portion of the left anterior descending coronary artery (LAD). The vasodilators used for hyperemia are adenosine and dipyridamole. However, the coronary vasodilative response and systemic hemodynamic effects of the two agents have not been directly compared with TTDE. We assessed blood flow velocity and vascular resistance in the distal LAD by TTDE during an intravenous 2-minute adenosine infusion (140 microg/kg/min) and low- (0.56 mg/kg) and high-dose dipyridamole (0. 84 mg/kg) infusion in 25 patients with patent LAD. Coronary flow velocity was successfully recorded in 20 patients (80%) during baseline and the consecutive vasodilator-infusion period. Compared with low-dose dipyridamole, adenosine infusion induced a higher CFR (3.7 +/- 0.87 vs 2.73 +/- 0.65; P <.05) and a lower coronary resistance index (0.31 +/- 0.04 vs 0.35 +/- 0.08; P <.05). But by increasing the dipyridamole dose to 0.84 mg/kg, the values of the CFR and coronary resistance index became comparable to those of adenosine infusion (2.85 +/- 0.78 vs 3.03 +/- 0.7, P = not significant [NS]; 0.33 +/- 0.04 vs 0.32 +/- 0.09, P = NS; respectively). We conclude that adenosine seems to be a favorable vasodilator for the measurement of CFR with TTDE.

Pylephlebitis associated with appendicitis.

Pylephlebitis usually occurs secondary to infection in the region drained by the portal venous system. A most common antesecent focus of infection is diverticulitis and the most common blood isolate is E. coli (54%), followed by Proteus mirabilis (23%). Overall mortality is 32% and most of the patients who had died had severe sepsis prior to the initiation of antibiotic therapy. We describe a case of pylephlebitis which had appendicitis and consequent septic thrombosis of the portal vein and its branches, with dissemination of infection to the liver. The patient had recovered due to timely antibiotic treatment alone and resulted in complete resolution. Early diagnosis and treatment are basic to a favorable clinical course.

Mercury inhalation poisoning and acute lung injury.

Acute mercury inhalation poisoning is a rare cause of acute lung injury. It is usually fatal because of progressive pulmonary failure. We experienced a patient with acute respiratory distress syndrome (ARDS) after illicit use of mercury vapor for hemorrhoid treatment; he developed acute chemical pneumonitis following exposure to mercury vapor. Prompt treatment with corticosteroids and penicillamine for acute chemical pneumonitis was instituted; radiologic pulmonary infiltrates disappeared within a week, but late phase neurologic sequelae and pulmonary interstitial fibrosis progressed.

A case of Wegener's granulomatosis complicated by diffuse pulmonary hemorrhage and thrombotic thrombocytopenic purpura.

Wegener's granulomatosis is a distinct form of necrotizing granulomatous vasculitis which usually affects the kidneys and the upper and lower respiratory tracts. Unusual manifestations have also been reported, and these include colitis, urethritis and diabetes insipidus. We describe a case of Wegener's granulomatosis which presented with rapidly progressive renal insufficiency, sudden deafness, red eye, facial palsy, and complicated by uncommon manifestations that were diffuse pulmonary hemorrhage and thrombotic thrombocytopenic purpura.