The template-assisted electrodeposition of platinum nanowires for catalytic applications

Template-assisted electrodeposition technique was applied to synthesize platinum nanowires (Pt NWs) on polycarbonate templates (PCT) with pore diameters of 15, 50, and 100 nm for catalytic applications. Influences of sulfuric acid added to the electrolyte, different potential scanning rates and different pore diameters of templates on the electrodeposition process of Pt NWs were investigated by electrochemical techniques, including voltammetry and chronoamperometry methods. It was confirmed that at lower scan rates and in acidic solutions, electrodeposition of platinum on templates with larger pores is controlled by diffusion. The potential range for deposition of Pt NWs was determined and the potentiostatic technique was utilized by applying various potentials of different durations to fabricate the NWs. The morphological characteristics of Pt NWs were examined using the scanning electron microscopy (SEM). It was shown that the growth of Pt NWs on PCT 50 nm followed a pine-tree pattern, while the Pt NWs grew spherically on PCT 100 nm. The uniform and compact shape of Pt NWs was verified by the transmission electron microscopy (TEM). The catalytic activities of the prepared Pt NWs with the same exchanged charge density for hydrogen adsorption/desorption and methanol oxidation reactions were determined by the cyclic voltammetry (CV) testing, and the superior electrocatalytic performance was detected for Pt NWs prepared on PCT 50 nm. This enhanced catalytic activity was attributed to the higher surface-to-volume ratio, larger electrochemical active surface area and higher density of exposed active sites accessible on the pine-tree morphology of these Pt NWs compared to the spherical structure of Pt NWs fabricated on PCT 100 nm. This makes Pt NWs prepared on PCT 50 nm to be a promising catalyst for direct methanol fuel cells (DMFCs)

99 mTc-MIBI washout as a complementary factor in the evaluation of idiopathic dilated cardiomyopathy (IDCM) using myocardial perfusion imaging

Rapid technetium-99 m methoxyisobutylisonitrile (99 mTc-MIBI) washout has been shown to occur in impairedmyocardia. This study is based on the hypothesis that scintigraphy can be applied to calculate the myocardial 99 mTc-MIBI washout rate (WR) to diagnose and evaluate heart failure severity and other left ventricular functional parameters specifically in idiopathic dilated cardiomyopathy (IDCM) patients. Patients with IDCMP (n = 17; 52.65 ± 11.47 years) and normal subjects (n = 6; 49.67 ± 10.15 years)were intravenously administered 99 mTc-hexakis-2-methoxyisobutylisonitrile (99 mTc-MIBI). Next, early and delayed planar data were acquired (at 3.5-h intervals), and electrocardiogram (ECG)-gated myocardial perfusion single photon emission computed tomography (SPECT) was performed. The 99 mTc-MIBI WR was calculated using early and delayed planar images. Left ventricular functional parameters were also analyzed using quantitative gated SPECT (QGS) data. In target group, myocardial WRs (29.13 ± 6.68%) were significantly higher than those of control subjects (14.17 ± 3.31%; P\0.001). The 99 mTc-MIBI WR increased with the increasing severity of the NYHA functional class (23.16 ± 1.72% for class I, 30.25 ± 0.95%for class II, 32.60 ± 6.73%for class III, and 37.50 ± 7.77% for class IV; P = 0.02). The WR was positively correlated with the end-diastolic volume (EDV) index (r2 = 0.216; b = 0.464; P = 0.02 [ml/m2], the end-systolic volume (ESV) index (r2 = 0.234; b = 0.484; P = 0.01 [ml/m2]), the summed motion score (SMS) (r2 = 0.544; b = 0.738; P = 0.00), and the summed thickening score (STS) (r2 = 0.656; b = 0.810; P = 0.00); it was negatively correlated with the left ventricular ejection fraction (LVEF) (r2 = 0.679; b = –0.824; P = 0.00). It can be concluded that 99 mTc-MIBI scintigraphy might be a valuable molecular imaging tool for the diagnosis and evaluation of myocardial damage or dysfunction severity