Improvement of electrical properties of pulsed laser crystallized silicon films by oxygen plasma treatment

Electrical properties of phosphorus-doped laser-crystallized silicon films were investigated. The analysis of free carrier optical absorption revealed that crystalline grains formed at laser energies of 360-375 mJ/cm 2 had high carrier mobilities of 40-50 cm 2 /Vs, which were close to that of doped single crystalline silicon. The mobility did not depend on the number of laser pulses. On the other hand, Hall effect measurements showed a marked increase in the carrier mobility of electrical current traversing grain boundaries from 3 to 28 cm 2 /Vs as the laser energy density increased from 160 to 375 mJ/cm 2 . The Hall mobility also increased as the number of laser pulses increased, although a single pulse irradiation resulted in a maximum carrier mobility of 15 cm 2 /Vs. These results suggest that a high laser energy density as well as numbers of multiple pulses are necessary to reduce disordered amorphous states and improve grain boundary properties

Detrimental effects of specific Periodontopathic bacterial infection on tachyarrhythmia compared to Bradyarrhythmia

Abstract Background Tachyarrhythmia (TA) and bradyarrhythmia (BA) are cardiac rhythm disorders that result in the decline of quality of life. While patients with periodontitis are at a high risk of cardiovascular disease (CVD), little causal information between TA and BA has been provided to date. To assess the relationship, periodontal bacterial infection in patients with TA or BA was evaluated. Methods The subjects were patients with TA (n = 98) or BA (n = 40) who attended Tokyo Medical and Dental University hospital. Periodontal and blood examinations were performed. Periodontopathic bacterial existence in saliva was evaluated. Results We found that specific periodontopathic bacteria, Porphyromonas gingivalis and Prevotella intermedia, were highly detected in saliva from TA patients compared to BA subjects. The rates of hypertension and dyslipidemia were comparable between the two groups. Conclusion Specific periodontal bacterial infection might affect TA progression