Development of Nanocomposite Powders for the SLS Process to Enhance Mechanical Properties

In an effort to fabricate prototypes with improved mechanical properties in the dual laser sintering process, functionalized graphite nanoplatelets were added to the PA-12 powder to produce a nanocomposite powder. The PA-12 powder was chosen as the matrix polymer because it has features conducive to laser sintering such as relatively low melting temperature and high mechanical properties. The GNPs were oxidized through a nitric acid treatment to improve the interfacial bonding. The resulting nanocomposite powder was layered and sintered by laser without any sign of agglomeration. Although the result is preliminary, it nevertheless shows the suitability of the nanocomposite powder for the laser sintering process.Mechanical Engineerin

Different Effects of Palmitoyl-L-carnitine and Palmitoyl-CoA on Mitochondrial Function in Rat Ventricular Myocytes

Although mitochondrial oxidative catabolism of fatty acid (FA) is a major energy source for the adult mammalian heart, cardiac lipotoxity resulting from elevated serum FA and enhanced FA use has been implicated in the pathogenesis of heart failure. To investigate the effects of the intermediates of FA metabolism, palmitoyl-L-carnitine (Pal-car) and palmitoyl-CoA (Pal-CoA), on mitochondrial function, we measured membrane potential(Δψm), opening of the mitochondrial permeability transition pore (mPTP) and the production of reactive oxygen species (ROS) in saponin-treated rat ventricular myocytes with a laser scanning confocal microscope. Our results revealed that: 1) lower concentrations of Pal-car (1 and 5μM) caused a slight hyperpolarization of Δψm (TMRE intensity increased to 115.5 ± 5.4 % and 110.7±1.6 % of the baseline, respectively. p<0.05) but did not open mPTP, 2) a higher concentration of Pal-car (10μM) depolarized Δψm (TMRE intensity decreased to 61.9 ± 12.2 % of the baseline, p<0.01) and opened mPTP (calcein intensity decreased to 70.7 ± 2.8% of the baseline, p<0.01), 3) Pal-CoA depolarized Δψm without opening mPTP, and 4) only the higher concentration of Pal-car (10μM) increased ROS generation (DCF intensity increased to 3.4 ± 0.3 fold of the baseline). We concluded that excessive exogenous intermediates of long chain saturated FA may disturb mitochondrial function in different ways between Pal-car and Pal-CoA. The distinct mechanisms of the deteriorating effects of long chain FA on mitochondrial function are important for our understanding of the development of cardiac diseases in systemic metabolic disorders.浜松医科大学学位論文　医博第517号(平成２０年１０月１７日

Accidental Entrapment of Electrical Mapping Catheter by Chiari’s Network in Right Atrium during Catheter Ablation Procedure

A 78-year-old male was admitted to our hospital due to frequent palpitation. His electrocardiogram (ECG) presented regular narrow QRS tachycardia with 170 bpm, and catheter ablation was planned. During electroanatomical mapping of the right atrium (RA) with a multiloop mapping catheter, the catheter head was entrapped nearby the ostium of inferior vena cava. Rotation and traction of the catheter failed to detach the catheter head from the RA wall. Exfoliation of connective tissue twined around catheter tip by forceps, which were designed for endomyocardial biopsy, succeeded to retract and remove the catheter. Postprocedural echocardiography and pathologic examination proved the existence of Chiari’s network. The handling of complex catheters in the RA has a potential risk of entrapment with Chiari’s network