Next generation 1.5 microm terahertz antennas: mesa-structuring of InGaAs/InAlAs photoconductive layers.

Mesa-structuring of InGaAs/InAlAs photoconductive layers is performed employing a chemical assisted ion beam etching (CAIBE) process. Terahertz photoconductive antennas for 1.5 microm operation are fabricated and evaluated in a time domain spectrometer.

Deterministic model for dose calculation in photon radiotherapy.

We present a model for dose calculation in photon radiotherapy based on deterministic transport equations. The model consists of two coupled equations, one for photon and one for electron transport and an equation for the absorbed dose. No assumptions are made with respect to the geometry or the homogeneity of the irradiated medium, so irradiation of any heterogenous medium can be simulated.

[Herpes simplex digitalis--an important differential diagnosis of paronychia].

Herpes simplex infection of the hand is often falsely diagnosed as a pyogenic paronychia or felon and treated as such, because the clinical picture is not known and pathogen isolation is difficult. However, the surgical treatment of herpes digitalis is contraindicated, since it promotes the development of superinfections and triggers recurrence. The pathogen can be isolated in cell cultures prepared from the vesicle contents or a smear from the vesicle base.

Adaptive changes in cats after long-term exposure to various temperatures.

Two groups of cats were exposed to 5 and 30 degrees C, respectively for 24 mo in climatic chambers under artificial illumination. Then the ambient temperatures were reversed for both groups for another 36 mo. The group adapted to cold for 36 mo showed an increase in fur growth (+35%), an increase in resting metabolism (+20%), and a shift in threshold of the cold-induced metabolic response to 8 degrees C lower ambient temperatures.

Static an dynamic activity of cold receptors in cats after long-term exposure to various temperatures.

Ten cats were adapted for 4.7 years in a climatic chamber to an ambient temperature of 5 degree C an 8 cats to 30 degree C under artificial illumination and food ad libitum., Cats living at 5 degree C had 15.

Activity of warm receptors in Boa constrictor raised at various temperatures.

Nine young specimens of Boa constrictor were raised for 4 years in a climatic chamber at an ambient temperature of 30 degrees C under artificial illumination. Seven boas were raised at 23 degrees C under the same conditions. At the end of the adaptation period, mean body weight of the warm adapted boas was 9.

Neural processes in long-term thermal adaptation.

Short-term habituation of cats to repeated cold stimuli includes a peripheral component owing to the dynamic response of cutaneous cold receptors. Long-term cold adaptation of up to 4 years causes significant changes in the static and dynamic cold fiber afferents from the cat's nose. These changes, however, do not seem to be essential for the adaptive changes of the thermoregulatory system.

Influence of cold adaptation on the activity of thermoresponsive neurons in thalamus and midbrain of the rat.

A group of 25 rats was adapted to cold by housing for five weeks at +3 degrees C. Using thermal stimuli of the scrotal skin, 53 recordings of warm-responsive thalamic and midbrain neurons were analyzed and compared with 84 control recordings from non-adapted rats. The activity of the analyzed neurons is characterized by a steep increase of firing rate above a certain temperature threshold zone.

The effect of whole body heat exposure and of cooling the hypothalamus on antibody titre in the rat.

In rats implanted with chronic hypothalamic thermodes and immunized with sheep erythrocytes, body temperature was increased, 4 h per day for 2 weeks, either by exposing the animals to external heat or by cooling the preoptic area. The titre of antibodies against sheep erythrocytes was nearly tripled by preoptic cooling but was drastically decreased by heat exposure. These opposing effects of active and passive increases in body temperature indicate that factors other than the change in body temperature must also have played a significant role in modifying the humoral immune response.

Sensory experiences in man evoked by intraneural electrical stimulation of intact cutaneous afferent fibers.

The response of slowly conducting myelinated and unmyelinated afferent units to natural types of cutaneous stimuli was recorded extracellularly with tungsten microelectrodes from intact human skin nerves. Seven fibers had characteristics of C-polymodal units (conduction velocity: 0.75-1.

Extra-auditory responses to long-term intermittent noise stimulation in humans.

Respiration, heart rate, cutaneous blood flow, and electroencephalogram (EEG) reactions to long-term intermittent noise exposure were recorded from 13 volunteers (20-29 yr) with normal hearing and vegetative reactivity. They received daily within 1 h 12 noise stimuli (16 s 100 dB (A) white noise) for 10 or 21 days, respectively. Most subjects reported partial subjective adaptation to the noise.

Parameters of the static burst discharge of lingual cold receptors in the cat.

Thermal stimuli were applied to the upper surface of the tongue of the cat. The stimuli ranged from 40 degrees C to 10 degrees C and were changed in cold steps of 5 degrees C, each temperature lasting 2 min. Afferent impulses of single specific cold fibers from the lingual nerve were analysed by a computer program.

Cold-sensitive afferents from the abdomen.

In cats afferent impulses from splanchnic and vagus nerve preparations were studied. In each splanchnic nerve serving the stomach or the adjacent part of the duodenum, cold-sensitive afferents could be recorded. There were also numerous mechanosensitive fibers originating from stomach, intestine, mesentery and the region of blood vessels.

The central control of shivering and non-shivering thermogenesis in the rat.

1. To test whether the preoptic area controls only non-shivering and the spinal cord only shivering thermogenesis, ten rats were chronically implanted with a preoptic and a spinal cord thermode each. The following were then studied: (a) the effect of propranolol (8 mg/kg.

Autonomic thermoregulation after intermittent cooling of the spinal cord and cold exposure in the rat.

1. O2 consumption, rectal and several skin temperatures were studied, at various ambient temperatures, in unanaesthetized rats that had been thermally stressed for an average of 290 h either by prolonged and intermittent cooling of the spinal cord or by prolonged and intermittent exposure to an ambient temperature which induced the same increase in O2 consumption as did the thermal stimulation of the spinal cord. 2.

The control of shivering and non-shivering thermogenesis in the rat.

1. The effect of intraperitoneal administration of propranolol (4, 8 and 12 mg/kg) on colonic temperature was studied in twelve rats during exposure to ambient temperatures of 30, 15 and 5 degrees C. 2.