Lick Observatory Optical SETI: targeted search and new directions.

Lick Observatory's Optical SETI (search for extraterrestrial intelligence) program has been in regular operation for 4.5 years. We have observed 4,605 stars of spectral types F-M within 200 light-years of Earth. Occasionally, we have appended objects of special interest, such as stars with known planetary systems. We have observed 14 candidate signals ("triple coincidences"), all but one of which are explained by transient local difficulties. Additional observations of the remaining candidate have failed to confirm arriving pulse events. We now plan to proceed in a more economical manner by operating in an unattended drift scan mode. Between operational and equipment modifications, efficiency will more than double.

[The usefulness of thoracic computerized tomography in patients in an intensive care unit]. / Het nut van computertomografie van de thorax bij patiënten op een intensive care-afdeling.

Performing thoracic CT scanning in critically ill patients can be cumbersome and may have detrimental effects on the condition of the patient. We retrospectively analysed the clinical data of 46 patients who were examined over a period of 4.5 years. The thoracic CT scanning was judged useful in 40 patients (87%) and beneficial for 23 (50%) of these. The principal indications for the investigation are: suspected pulmonary abscess, suspected mediastinitis, precise localisation of an intrathoracic lesion prior to surgery, difficulty in the evaluation of the pulmonary parenchyma in patients with deforming thoracic kyphoscoliosis, suspected trapped pleural fluid and a suspected thoracic focus of sepsis. Transport had no detrimental effects on any of the patients. If the decision to undertake CT scanning is arrived at jointly by the radiologist and intensive care physicians, CT scanning is useful and can be performed safely if transport is undertaken by an experienced team.

An unusual case of cuff herniation.

We describe a case of herniation of an endotracheal tube with a high volume and low pressure cuff. In contrast with the conventional endotracheal tube with a low volume and high pressure cuff, which, after recognition of cuff herniation, can be deflated, the herniation of this type of tube could not be resolved in such a way. The large and soft cuff material had spread itself over the tube tip, as a result of the herniation and this was aggravated by deflation, making it impossible to adequately ventilate the patient. Pulse oximetry turned out to be a most helpful way of monitoring the seriousness of the situation, in which the patient was fully covered by sterile drapes.

Effects of neostigmine, edrophonium, 4-aminopyridine and their combinations.

A study was carried out in the in-vitro rat phrenic nerve hemidiaphragm preparation to find a fast and strong working antagonist of non-depolarizing muscle relaxants. We studied neostigmine, edrophonium, 4-aminopyridine and their combinations from the cumulative concentration response curves of pancuronium. Neostigmine, edrophonium and 4-aminopyridine all antagonized the effect of pancuronium. Neostigmine and 4-aminopyridine did potentiate each other as did neostigmine and edrophonium. The combination of edrophonium and 4-aminopyridine showed less total effect than the addition of their individual effect. We conclude that the mechanisms of action of neostigmine and edrophonium are different.

A patchy loco-regional hypalgesia due to subdural catheter placement.

We discuss a unique case of perforation of the dura mater, but not of the arachnoidea, by an epidural catheter. The injected test dose of the local anesthetic agent caused a partial subdural and a partial epidural hypalgesia. The exact position of the catheter and the distribution of the local anesthetic agent was confirmed by radiographic contrast material.

Calcium antagonism of the block in excitation-contraction coupling produced by a urea exposure-removal treatment.

Exposing frog's toe muscles to Ringer's solution made hypertonic with 400 mM urea for 60 min followed by placing the muscles back in Ringer's (urea-removal treatment) completely blocks the twitch without disrupting the surface openings of the T-tubules. The urea-removal treatment also increased the triadic junction width. Placing the muscles in Ringer's with an elevated calcium concentration (5 mM) following exposure to the hyertonic solution prevented the block of the twitch response but not the increase in the triadic junction width. Exposing untreated muscles to Ringer's with 5 mM calcium either had no effect on the twitch on reduced it by 30 percent or less. These results suggest the possibility that increasing the width of the triadic junction decreases the amount of calcium ions reaching the terminal cisternae during an action potential thereby blocking the twitch. Elevating the calcium concentration in the T-tubules would increase the amount of calcium which enters the triadic junction during an action potential and thus antagonize the above effects.

Signal-to-noise ratio in Fourier spectroscopy.

Calculations of the SNR obtainable with a Fourier transform spectrometer as well as that obtainable with a photometer or scanning device are presented. It is shown that the SNR obtained with a Fourier spectrometer is (N/8)(1/2) greater than that obtained with a scanning device (where N is the desired number of spectral elements scanned). Reasons why this factor, known as the multiplex advantage, differs from other values found in the literature are discussed.