Optical projection tomography implemented for accessibility and low cost (OPTImAL).

Optical projection tomography (OPT) is a three-dimensional mesoscopic imaging modality that can use absorption or fluorescence contrast, and is widely applied to fixed and live samples in the mm-cm scale. For fluorescence OPT, we present OPT implemented for accessibility and low cost, an open-source research-grade implementation of modular OPT hardware and software that has been designed to be widely accessible by using low-cost components, including light-emitting diode (LED) excitation and cooled complementary metal-oxide-semiconductor (CMOS) cameras. Both the hardware and software are modular and flexible in their implementation, enabling rapid switching between sample size scales and supporting compressive sensing to reconstruct images from undersampled sparse OPT data, e.g. to facilitate rapid imaging with low photobleaching/phototoxicity. We also explore a simple implementation of focal scanning OPT to achieve higher resolution, which entails the use of a fan-beam geometry reconstruction method to account for variation in magnification. This article is part of the Theo Murphy meeting issue 'Open, reproducible hardware for microscopy'.

openFrame: A modular, sustainable, open microscopy platform with single-shot, dual-axis optical autofocus module providing high precision and long range of operation.

'openFrame' is a modular, low-cost, open-hardware microscopy platform that can be configured or adapted to most light microscopy techniques and is easily upgradeable or expandable to multiple modalities. The ability to freely mix and interchange both open-source and proprietary hardware components or software enables low-cost, yet research-grade instruments to be assembled and maintained. It also enables rapid prototyping of advanced or novel microscope systems. For long-term time-lapse image data acquisition, slide-scanning or high content analysis, we have developed a novel optical autofocus incorporating orthogonal cylindrical optics to provide robust single-shot closed-loop focus lock, which we have demonstrated to accommodate defocus up to ±37 µm with <200 nm accuracy, and a two-step autofocus mode which we have shown can operate with defocus up to ±68 µm. We have used this to implement automated single molecule localisation microscopy (SMLM) in a relatively low-cost openFrame-based instrument using multimode diode lasers for excitation and cooled CMOS cameras.

Uncertainty of measurement. Twenty years afterwards.

The application of the concept "uncertainty" causes considerable difficulties. In this paper an analysis of the intrinsic contradictions of the concept itself and its relationship with the statements of metrology is given with the aim of establishing possible reasons for these difficulties. As a result of this analysis several examples are presented to demonstrate the conflicts of the concept and its several statements in the general fundamental notions of metrology.

A subset of cingulate cortical neurones is specifically activated during alcohol-acquisition behaviour.

UNLABELLED: A new need is associated with the formation of behaviour directed at its satisfaction. In chronically ethanol-treated rabbits a bodily need develops to acquire and consume alcohol. The present study examined the firing properties of single neurones in the cingulate (limbic) cortex of chronically ethanol-treated rabbits. The main questions of this study were: are there neurones in the cingulate cortex which specifically increase their firing during alcohol-acquisition behaviour (AAB)? What is the relationship between the neuronal mechanisms of pre-existing and newly formed behaviour? Adult rabbits were taught to acquire food by pressing pedals. After 9 months of ethanol treatment, the same rabbits were taught to acquire ethanol (15% solution in a 0.5-mL capsule) by means of the same instrumental METHOD: Activity of the 118 neurones was recorded from the cingulate cortex. The comparison of activity of each neurone in AAB and food-acquisition behaviour (FAB) enabled us to reveal that their subservings overleap substantially but not completely: 41% of 'common neurones' involved in the subserving of both FAB and AAB as well as 5% of 'alcohol-neurones' (alcohol-acquisition specific cells) were found. We think of the latter neurones as units that were specialized during the forming of alcohol-seeking behaviour. Thus, present experiments help us not only to answer the above questions but also to provide an additional insight into the nature of similarity between neuronal mechanisms of long-term memory and long-lived modifications resulting from repeated drug exposure.

Neuronal subserving of behavior before and after chronic ethanol treatment.

We have previously shown that an acute ethanol dose (1 g/kg), sufficient to impair the performance of a healthy rabbit, also reversibly depresses the activity of those limbic-cortex neurons that are specifically activated during recently learned behavioral acts. Our new morphological and neurophysiological data suggest a death of such neurons after 9-month chronic ethanol treatment. The effect of acute ethanol administration on neurons and performance speed in alcoholic rabbits was opposite to that found in healthy animals. Our results help to understand why neurocognition of alcoholics changes and why acute low-level alcohol ingestion influences them differently than healthy individuals.

Surgical treatment of Chiari I malformation with or without syringomyelia.

102 patients with Chiari I malformation with or without syringomyelia underwent primary reconstructive operation at the craniocervical junction (CCJ). We present here the indications, methods of surgical management with clinical, radiological and operative findings. Here we present the results of a retrospective review. The authors discuss the possible ways of improvement in the results of "hindbrain related" syrngomyelia treatment.

Differential effects of alcohol on the cortical processing of foreign and native language.

The effect of alcohol (ethanol) on cortical processing of Finnish vs. English words in Finnish-speaking subjects was studied by recording auditory event-related potentials in 10 subjects who had started studying English at the age of 9-10 years. At the beginning of the block of 100 words, the subject heard an introductory sentence. Half of the words completed the sentence well and the other half did not. The subject pressed a reaction key immediately after hearing a proper word. After the control condition, the subject ingested alcohol (1 ml/kg). Alcohol attenuated the amplitude of N100 to both Finnish and English words, this attenuation being significantly stronger for English than for Finnish words. The early differential effect of alcohol suggests that language-specific information is extracted in the cortex already approximately 100 ms from the word onset. The results are in line with animal experiments demonstrating that alcohol selectively affects the activity of single units involved in newer forms of behavior.

Changes of auditory-evoked potentials in response to behaviorally meaningful tones induced by acute ethanol intake in altricial nestlings at the stage of formation of natural behavior.

Acute ethanol's influence on field L auditory-evoked potentials (AEP) was studied in 4-7-days-old altricial nestlings of the pied flycatcher. Nestlings were presented with behaviorally meaningful tone pips (2.0 and 5.0 kHz) and control tone pips (3.0 kHz). Ethanol ingestion was found to reduce the N1 amplitude and maturity index (MI) of the AEP in response to "behavioral" but not to control frequencies. This effect was first observed on day 5, when the nestlings' behavior became more complex (their eyes opened and defence behavior appeared), and when previously formed feeding behavior was undergoing modifications. The MI increase during the early postembryonic ontogeny was probably due to the selective involvement of neurons with newly formed behavioral specializations into the subserving of new behavioral patterns, while the decrease of the MI under alcohol was due to the depression of activity in these neurons.

Acute effects of alcohol on unit activity in the motor cortex of freely moving rabbits: comparison with the limbic cortex.

Unit activity was recorded from the motor cortex of eight freely moving rabbits in order to examine the acute effect of ethanol (1 g kg-1) on organization of unit activity and to compare it with our earlier results from the limbic cortex. The rabbits performed a food-acquisition task in the experimental cage. Unit activity was recorded during behaviour in the control experiment followed by the alcohol experiment on the next day. After ethanol, behavioural mistakes and the duration of the behavioural cycle significantly increased. In the control experiments activation of 58% of the units had no constant relation to the phases of the behavioural cycle (non-involved units), whereas 42% of the units were constantly activated during certain phases (involved units). Two per cent of the latter units were activated in relation to newly learned behavioural acts (e.g. pedal pressing; L units), 28% in relation to food seizure and/or grinding (S units) and 12% in relation to certain movements during different behavioural acts (M units). Ethanol had no effect on the number of active units and the same relation between the number of non-involved and involved units or between the number of different types of involved units was found. However, the number of involved units decreased in the upper and increased in the lower cortical layers. Also the number of units with low background frequency increased, although the frequency within activations did not change. In our earlier study the number of active units in the limbic cortex decreased after ethanol by one third and the relation between the number of L and M units was reversed.(ABSTRACT TRUNCATED AT 250 WORDS)

Overview of VEGA Venus Balloon in Situ Meteorological Measurements.

The VEGA balloons made in situ measurements of pressure, temperature, vertical wind velocity, ambient light, frequency of lightning, and cloud particle backscatter. Both balloons encountered highly variable atmospheric conditions, with periods of intense vertical winds occurring sporadically throughout their flights. Downward winds as large as 3.5 meters per second occasionally forced the balloons to descend as much as 2.5 kilometers below their equilibrium float altitudes. Large variations, in pressure, temperature, ambient light level, and cloud particle backscatter (VEGA-1 only) correlated well during these excursions, indicating that these properties were strong functions of altitude in those parts of the middle cloud layer sampled by the balloons.

Determination of Venus Winds by Ground-Based Radio Tracking of the VEGA Balloons.

A global array of 20 radio observatories was used to measure the three-dimensional position and velocity of the two meteorological balloons that were injected into the equatorial region of the Venus atmosphere near Venus midnight by the VEGA spacecraft on 11 and 15 June 1985. Initial analysis of only radial velocities indicates that each balloon was blown westward about 11,500 kilometers (8,000 kilometers on the night side) by zonal winds with a mean speed of about 70 meters per second. Excursions of the data from a model of constant zonal velocity were generally less than 3 meters per second; however, a much larger variation was evident near the end of the flight of the second balloon. Consistent systematic trends in the residuals for both balloons indicate the possibility of a solar-fixed atmospheric feature. Rapid variations in balloon velocity were often detected within a single transmission (330 seconds); however, they may represent not only atmospheric motions but also self-induced aerodynamic motions of the balloon.

Venus: detailed mapping of maxwell montes region.

From October 1983 to July 1984, the north hemisphere of Venus, from latitude 30 degrees to latitude 90 degrees , was mapped by means of the radar imagers and altimeters of the spacecraft Venera 15 and Venera 16. This report presents the results of the radar mapping of the Maxwell Montes region, one of the most interesting features of Venus' surface. A radar mosaic map and contour map have been compiled.

Specificity of visual and motor cortex neurons activity in behavior.

The involvement of the units of visual (VC) and motor cortex (MC) in the systemic behavioral mechanisms is determined by the "environment" and "executive mechanisms of behavior". The unit activity in VC and MC, head and lower jaw movements, EMG of m. masseter and latency of touching the food were recorded. In experiment I the rabbits’ eyes were covered with occluders that were put on and taken off after every 4-5 repetitions of the behavioral act. It was found that the visual inflow was not necessary for the activations of both MC and VC neurons to appear. The pattern of neuronal activity changed when behavioral act was performed with the eyes closed. These changes following the "visual" influences were more pronounced in the VC. In experiment II the unit activity of both cortical areas was compared during the free head movement towards food and during the movement hampered with the rubber thread. The more pronounced susceptibility of VC neurons to activity changes was demonstrated again, this time after motor influences.