Posthyperventilation apnea associated with severe hypoxemia

We studied a 14-year-old girl who suffered fractures of her mandible and tegmen following a fall from a balance beam. Thirteen days after hospitalization, she developed severe, protracted, recurrent episodes of hyperventilation; subsequently, she suffered posthyperventilation apnea, which at times was prolonged and association with severe hypoxemia with an arterial oxygen pressure as low as 25 mm Hg. The patient was treated with added dead space and chlorpromazine hydrochloride (Thorazine). Postulated mechanisms for her disorder are discussed. The importance of close clinical and laboratory observation in similar cases is stressed.     

Diaphragm activation with intramuscular stimulation in dogs

We studied in 10 supine anesthetized dogs diaphragm contraction produced by electrical activation with intramuscular electrodes surgically implanted in the ventral surface of the diaphragm and compared this with activation of the ipsilateral phrenic nerve (C5, 6, and 7) before it entered the thorax. Repetitive 40-Hz pulse trains with supramaximal current stimulus were used after hyperventilation of the animals to apnea. A single intramuscular electrode within 1 to 2 cm of the site of phrenic nerve entry into the diaphragm produced a mean transdiaphragmatic pressure of 12.0 cm H2O +/- 0.97 SE and mean tidal volume of 0.27 L +/- 0.04 SE. Mean values observed with phrenic nerve stimulation were not statistically different, and both electrode systems produced equivalent outward abdominal motion and upper rib cage paradox, as monitored by inductive plethysmography. There was no difference in gas exchange during stimulation with a single hemidiaphragm electrode and mechanical ventilation compared at the same tidal volume and respiratory rate. Blockade of neuromuscular transmission with curare eliminated intramuscular and phrenic nerve stimulation proportionately, suggesting that activation of the diaphragm is dependent in both cases on the phrenic nerve. This technique does not entail manipulation of the phrenic nerve and may have clinical application as an alternative technique for diaphragm pacing.     

电力市场下电压偏离的经济补偿问题

随着电力体制改革和电力市场的逐步发展和完善 ,对由于供应商管理或运行不当造成的电能质量的下降进行经济补偿已成为在电力市场运营中出现的新问题。目前的补偿依据均缺乏一定的理论基础 ,不能反映电能质量偏离所造成的经济损失。为此提出利用电压灵敏度与最优潮流的综合分析结果来评估其经济损失 ,仿真结果表明新方法取得了令人满意的结果     

Meeting the Software Challenge: A Model for is Transformation

As economic and technological trends create spiraling demand for software resources, IS managers must increasingly weigh the risks of new technology against the costs of falling behind. in this environment, successful management of the IS organization depends less on the transfer of technological implements than on adopting the characteristics of a learning organization: a mature process, a culture supportive of continuous change, and effective management.