In situ transmission electron microscopy studies have been carried out to determine the
effect of temperature and pressure on the growth of carbon nanotubes by the Ni-catalyzed
chemical vapour deposition of acetylene. The temperature range explored was
450–650 °C
and the acetylene pressure range was 0.8–20 mTorr. Our observations show that straight,
single-wall, carbon nanotubes tend to form at higher temperatures and lower pressures
while bent, zigzag, multi-wall carbon nanotubes form at lower temperatures and
higher pressures. These results can be understood as the result of competition
between the arrival rate of carbon and the nucleation rate of carbon hexagons
(which increases at high pressure and low temperature), and the annealing rate of
the 5-ring and 7-ring defects that are responsible for the nanotube curvature.
The mediolateral and anteroposterior position of the jugular bulb determines encroachment of the surrounding structures. An abnormal position is postulated to contribute to the development of Ménière's disease.
The causative role of Demodex folliculorum should be considered in immunocompetent children with rosacea or rosacea-like refractory eruptions. In such cases, treatment with ivermectin can be beneficial.
In a long-term care facility, whose residents have been diagnosed with Alzheimer's disease or dementia, falls are a particularly prominent issue. Technology in health care has continued to evolve and play a larger role in how we care for our patients, even in preventing falls. However, overreliance on these types of technologies may have detrimental effects. In our facility, it was felt that staff reliance on position-change alarms was inappropriate due to the high rate of false alarms associated with these devices. We took a tiered approach to removing position-change alarms from our facility, monitoring the fall incidence rate for a period before, during, and after the elimination of these alarms. After discontinuing their use, we found a decrease in the rate of falls, and a decrease in the percentage of our residents who fell. Staff has easily adapted and reports a calmer, more pleasant environment.
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