Stroke induces long-lasting deficits in the temporal fidelity of sensory processing in the somatosensory cortex.

Recovery from stroke is rarely complete as humans and experimental animals typically show lingering deficits in sensory function. One explanation for limited recovery could be that rewired cortical networks do not process sensory stimuli with the same temporal precision as they normally would. To examine how well peri-infarct and more distant cortical networks process successive vibro-tactile stimulations of the affected forepaw (a measure of temporal fidelity), we imaged cortical depolarizations with millisecond temporal resolution using voltage-sensitive dyes.

α4* Nicotinic acetylcholine receptors modulate experience-based cortical depression in the adult mouse somatosensory cortex.

The molecular mechanisms that mediate experience-based changes in the function of the cerebral cortex, particularly in the adult animal, are poorly understood. Here we show using in vivo voltage-sensitive dye imaging, that whisker trimming leads to depression of whisker-evoked sensory responses in primary, secondary and associative somatosensory cortical regions. Given the importance of cholinergic neurotransmission in cognitive and sensory functions, we examined whether α4-containing (α4*) nicotinic acetylcholine receptors (nAChRs) mediate cortical depression.

The Suess-Urey mission (return of solar matter to Earth).

The Suess-Urey (S-U) mission has been proposed as a NASA Discovery mission to return samples of matter from the Sun to the Earth for isotopic and chemical analyses in terrestrial laboratories to provide a major improvement in our knowledge of the average chemical and isotopic composition of the solar system. The S-U spacecraft and sample return capsule will be placed in a halo orbit around the L1 Sun-Earth libration point for two years to collect solar wind ions which implant into large passive collectors made of ultra-pure materials. Constant Spacecraft-Sun-Earth geometries enable simple spin stabilized attitude control, simple passive thermal control, and a fixed medium gain antenna.

Skiing injuries: the increasing workload.

All skiing injuries presenting to a fracture clinic during the period December 1992 to April 1993 were studied. Fifty five patients with 59 injuries were treated during this period. Thirty (54.

Poor results of the Ribbed Hip System for cementless replacement.

We reviewed 12 patients six years after they had undergone total hip replacement with a cementless prosthesis, the Ribbed Hip System (Waldemar Link GmbH & Co, Hamburg, Germany). Aseptic loosening of one or both components had necessitated revision surgery in seven patients, in five within two years of operation. In view of our experience we question the wisdom of allowing the uncontrolled use of new prosthesis without postoperative surveillance.

Distal fibulectomy for Ewing's sarcoma.

We treated five children with non-metastatic Ewing's sarcoma of the distal fibula by distal fibulectomy. At a mean of eight years after surgery they all had nearly normal levels of painfree function. Distal fibulectomy is a good alternative to the more radical amputations recommended in the past.

An audit of the effect of a 24-hour emergency operating theatre in a district general hospital.

The recent introduction of a 24-hour emergency theatre for General Surgery provided an opportunity to audit its effect on emergency operating in a District General Hospital. Prior to its introduction much of the emergency operating was determined by theatre availability rather than clinical need. Half of the emergency operations were carried out between 10 pm and 8 am.

The injured motor cycle messenger.

Injured motor cycle messengers make up a small but significant proportion of the young injured attending Central London accident and emergency (A&E) departments. The study confirms that the pattern of their injuries is similar to other injured urban motor cyclists, and discusses the background of the injured, in terms of experience and training, highlighting the frequency of injury and possible predisposing factors. A total of 116 injured motor cycle messengers attending two Central London A&E departments over a 10-month period were studied.

Voyager radio science observations of neptune and triton.

The Voyager 2 encounter with the Neptune system included radio science investigations of the masses and densities of Neptune and Triton, the low-order gravitational harmonics of Neptune, the vertical structures of the atmospheres and ionospheres of Neptune and Triton, the composition of the atmosphere of Neptune, and characteristics of ring material. Demanding experimental requirements were met successfully, and study of the large store of collected data has begun. The initial search of the data revealed no detectable effects of ring material with optical depth tau [unknown] 0.

Quality control in the IVF laboratory: in-vitro and in-vivo development of mouse embryos is unaffected by the quality of water used in culture media.

We have examined the effect of media made with tap water or with various purified waters on the fertilization of mouse oocytes, their development to blastocysts, their rate of hatching in vitro and their survival after transfer to recipients. Zona-intact and zona-free embryos, as well as cell clusters from 8-cell stage embryos, were also used. The macromolecular composition of the media was varied.

Magnetic resonance imaging: comparison of four pulse sequences in assessing primary bone tumours.

A prospective magnetic resonance imaging (MRI) study was carried out in 13 patients (19 examinations) with primary bone tumours to assess the relative value of each of four pulse sequences in showing the extent and nature of the lesion. The four pulse sequences used were a T1-weighted spin-echo (SE544/44), a T2-weighted spin echo (SE1500/80), a short TI inversion recovery (STIR) (IR500/100/44), and a partial saturation (PS) (PS500/22) with field echo data collection. For soft tissue disease the combination of PS and STIR gave better definition of the boundary of the tumour than the more conventional T1 and T2-weighted spin echo sequences.

Voyager 2 radio science observations of the uranian system: atmosphere, rings, and satellites.

Voyager 2 radio occultation measurements of the Uranian atmosphere were obtained between 2 and 7 degrees south latitude. Initial atmospheric temperature profiles extend from pressures of 10 to 900 millibars over a height range of about 100 kilometers. Comparison of radio and infrared results yields mole fractions near the tropopause of 0.

Multiple chondrosarcomas in dyschondroplasia (Ollier's disease).

The relationship between dyschondroplasia (Ollier's Disease) and the possibility of malignant change is well known. The authors describe a patient who developed four primary chondrosarcomas over 11 years. These were treated by local wide excision and, in two sites, prosthetic replacement to preserve the limb.

Vertical structure of the ionosphere and upper neutral atmosphere of saturn from the pioneer radio occultation.

Radio occultation measurements at S band (2.293 gigahertz) of the ionosphere and upper neutral atmosphere of Saturn were obtained during the flyby of the Pioneer 11 Saturn spacecraft on 5 September 1979. Preliminary analysis of the occultation exit data taken at a latitude of 9.

Atmosphere of jupiter from the pioneer 11 s-band occultation experiment: preliminary results.

Two additional radio occultation measurements of the atmosphere of Jupiter were obtained with Pioneer 11. The entry measurement leads to a temperature profile that is substantially in agreement with those obtained with Pioneer 10, showing temperatures much higher than those derived from other observations. The exit measurement is not usable because of the discontinuous drift of the spacecraft auxiliary oscillator, presumably due to the trapped radiation belts of Jupiter.

Mercury: results on mass, radius, ionosphere, and atmosphere from mariner 10 dual-frequency radio signals.

Analysis of the radio-tracking data from Mariner 10 yields 6,023,600 +/- 600 for the ratio of the mass of the sun to that of Mercury, in very good agreement with values determined earlier from radar data alone. Occultation measurements yielded values for the radius of Mercury of 2440 +/- 2 and 2438 +/- 2 kilometers at laditudes of 2 degrees N and 68 degrees N, respectively, again in close agreement with the average equatorial radius of 2439 +/- 1 kilometers determined from radar data. The mean density of 5.

Venus: mass, gravity field, atmosphere, and ionosphere as measured by the mariner 10 dual-frequency radio system.

Analysis of the Doppler tracking data near encounter yields a value for the ratio of the mass of the sun to that of Venus of 408,523.9 +/- 1.2, which is in good agreement with prior determinations based on data from Mariner 2 and Mariner 5.