Time-domain control of ultrahigh-frequency nanomechanical systems

Nanoelectromechanical systems could have applications in fields as diverse as ultrasensitive mass detection and mechanical computation, and can also be used to explore fundamental phenomena such as quantized heat conductance and quantum-limited displacement. Most nanomechanical studies to date have been performed in the frequency domain. However, applications in computation and information storage will require transient excitation and high-speed time-domain operation of nanomechanical systems. Here we show a time-resolved optical approach to the transduction of ultrahigh-frequency nanoelectromechanical systems, and demonstrate that coherent control of nanomechanical oscillation is possible through appropriate pulse programming. A series of cantilevers with resonant frequencies ranging from less than 10 MHz to over 1 GHz are characterized using the same pulse parameters.

Comparison of motor unit activation during unilateral and bilateral leg extension

Possible differences between the extent of muscle utilization during leg extensions performed bilaterally (BL, both legs acting together) and unilaterally were investigated in young males in college. Significantly less integrated electromyographic activity was recorded from the quadriceps muscles of the dominant leg during BL compared with UL maximal voluntary contractions (MVC). BL strength was significantly lower than the summed (UL; sum of 2 legs acting singly) UL value under isometric conditions [BL = 91 +/- 2.5% (mean +/- SE) of UL; P less than 0.01, n = 9]. By use of a modified isokinetic dynamometer, it was also shown that the effect of increasing the velocity of concentric contraction was significantly greater (P less than 0.001) on BL than UL force development; thus at 424 degrees/s mean BL MVC was only 51 +/- 3.5% of UL. Greater resistance to fatigue was shown in the BL condition in repeated concentric contractions (% decline over 100 MVC at 105 degrees/s was 28 +/- 2.7% for BL vs. 38 +/- 2.9% for UL, P less than 0.001). Results indicated that the extent of motor unit activation appeared to be reduced in BL relative to UL MVC. Compatible evidence from the strength-velocity and fatigability comparisons suggested that this reduction was due to a lesser utilization of the fast-twitch fatigable type of motor unit.

[Intensive treatment of subarachnoid hemorrhage with objective worsening of patient status]

In the years 1971-1978 a group of 915 patients with subarachnoideal haemorrhage were treated at the Department of Neurosurgery, Medical Academy in Cracow. Surgical treatment was applied in 584 cases (63.82%). In 92 cases (10.05%) intensive treatment vas applied in view of deterioration in the course of the disease. The patients requiring intensive treatment were divided into 3 groups depending on the time of deterioration development (recurrence of subarachnoideal haemorrhage--27%, after angiography--11%, after surgical elimination of the aneruysm from the circulation--62%). The authors discuss the clinical symptoms and signs of deterioration, therapeutic management and nutrition. In the group with deterioration 76.08% of patients died, including 47.82% after operations. Deterioration was survived by 23.91%.

Blood cyanide and thiocyanate concentrations after administration of sodium nitroprusside as hypotensive agent in neurosurgery

In a group of 50 neurosurgical patients receiving sodium nitroprusside as a hypotensive agent, in doses of 50--2131 microgram/kg body weight, whole blood cyanide was estimated before infusion of drug, during infusion, immediately after infusion, and 1 and 3 h later. Cyanide values increased significantly, reaching the maximum in a sample taken immediately after infusion (mean value, 333; highest value, 1800 microgram/liter). Values correlated closely with both dose and rate of infusion. Blood thiocyanate, estimated before, immediately after, and 3 h after the infusion, showed no significant changes in thiocyanate concentration. In any case, no signs or symptoms of cyanide or thiocyanate poisoning were observed. We conclude that sodium nitroprusside, in the proper dose and given at the proper rate, does not precipitate cyanide poisoning.

Blood cyanide and thiocyanate concentrations after administration of sodium nitroprusside as hypotensive agent in neurosurgery

In a group of 50 neurosurgical patients receiving sodium nitroprusside as a hypotensive agent, in doses of 50--2131 microgram/kg body weight, whole blood cyanide was estimated before infusion of drug, during infusion, immediately after infusion, and 1 and 3 h later. Cyanide values increased significantly, reaching the maximum in a sample taken immediately after infusion (mean value, 333; highest value, 1800 microgram/liter). Values correlated closely with both dose and rate of infusion. Blood thiocyanate, estimated before, immediately after, and 3 h after the infusion, showed no significant changes in thiocyanate concentration. In any case, no signs or symptoms of cyanide or thiocyanate poisoning were observed. We conclude that sodium nitroprusside, in the proper dose and given at the proper rate, does not precipitate cyanide poisoning.

[Early complications following intracranial surgery]

The authors discuss early non-inflammatory postoperative complications developing in the first week after operations. The reported material comprised 97 patients from among 1 815 cases treated surgically in the years 1971--1973 at the Departments of Neurosurgery and Neurotraumatology, Medical Academy in Cracow. The most frequent causes of reoperations were brain oedema, epidural haematoma and haematoma in the empty space left after evacuation of lesion. In the group of reoperated patients the percent of fatal cases increased to 56,7%.