Spectral sidebands on a narrow-bandwidth optical probe as a broad-bandwidth THz pulse diagnostic.

Broad-bandwidth THz-domain electro-magnetic pulses are typically diagnosed through temporal electro-optic (EO) cross-correlation with an optical probe pulse. Single-shot time-domain measurements of the THz waveform involve complex setups at a bandwidth coverage limited by the probe bandwidth. Here we present an EO-based diagnostic directly in the spectral domain, relying on THz-induced optical sidebands on a narrow-bandwidth optical probe. Experiments are conducted with a 0.11-THz-bandwidth optical probe and a broadband source (0-8 THz detection bandwidth) rich in spectral features. The validity of the sideband diagnostic concept, its spectral resolution, sideband amplitude, and the effects of probe timing are studied. For probe pulses longer than the THz pulse, the sideband technique proves an accurate single-shot spectral diagnostic, with advantages in setup simplicity and bandwidth coverage no longer limited by the laser bandwidth.

The development of lateral event-related potentials (ERPs) related to word naming: a four year longitudinal study.

Event-related potentials (ERPs) were recorded from the left and right temporal and parietal sites during a word naming task. Subjects were a group of children that were followed over four consecutive years starting at Kindergarten. ERP waveforms contained a sequence of positive and negative components (N150, P240, N360, N530 and SW). All components, except N150, showed changes in amplitude as a function of age, whereas SW, N360 and N150 also changed in hemispheric distribution. In addition, a relationship was found between reading performance and ERP amplitudes over the right parietal hemisphere in young children, and over the left temporal hemisphere in older children. Proficient readers showed larger (more negative) parietal N530 amplitudes than less proficient readers, especially when stimuli were degraded words. The results are discussed in terms of age-related changes in right and left hemisphere functions involved in early and advanced stages of reading, that might possibly be related to visual word recognition.

Alterations in molecular species of cholesterol esters formed via plasma lecithin-cholesterol acyltransferase in human subjects consuming fish oil.

The influence of a dietary supplement of n-3 polyunsaturated fatty acids containing eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) on the molecular species of cholesteryl esters (CE) formed via the plasma lecithin (phosphatidylcholine)-cholesterol acyltransferase (LCAT; EC 2.3.1.43) reaction was evaluated. For this purpose, one group of eight subjects received an encapsulated fish lipid concentrate (MaxEPA) and another group of eight volunteers in the control group received encapsulated olive oil for 22 days. Plasma lipid profiles and fatty acid compositions of plasma phosphatidylcholine (PC) and CE were measured at day 0 and day 22 in all subjects. A decrease in plasma triglyceride (by 34%) and a moderate rise in high-density lipoprotein (HDL)-cholesterol (by 13%) was observed in the MaxEPA group. For characterization of the plasma LCAT-derived reaction products formed in vitro, [14C]cholesterol was used as the substrate and the newly formed molecular species of [14C]CE were separated by argentation thin-layer chromatography. Marked shifts were found in the abundance of the various classes of LCAT-derived products in the MaxEPA group whereas no significant changes were observed in the controls. The proportion of the [14C]CE as pentaenoic (EPA) species rose by 9-fold (from 1.5% at day 0 to 14.4% at day 22) as the dienoic (linoleate) species fell (from 50.6 to 39.2%); a moderate rise in the hexaenoic (DHA) species (from 1.7 to 2.4%) with no significant change in the tetraenoic (arachidonate) (AA) species was observed. The LCAT results were in the order of the observed shifts in the fatty acid patterns of the plasma CE.(ABSTRACT TRUNCATED AT 250 WORDS)

Whole-lung lavage under hyperbaric oxygen conditions for alveolar proteinosis with respiratory failure.

Whole-lung lavage under hyperbaric oxygen conditions was performed in two patients suffering from severe respiratory insufficiency in pulmonary alveolar proteinosis. Under these conditions, gas exchange was maintained and the mixed venous partial pressure of oxygen and oxygen saturation showed increases to acceptable levels. This enabled us to limit the FIO2 in order to extend the oxygen tolerance and to perform lavage procedures more effectively. Both patients showed a very significant improvement of their clinical course, and we conclude that elective use of hyperbaric oxygen in unilateral lung lavages should be considered in these severe cases.

Hemispheric specialization in children as reflected in the longitudinal development of ear asymmetry.

The longitudinal development of ear asymmetry has been investigated in two samples of kindergarten and primary school children over an age range of six years. Ear preference in a dichotic digit test, administered four times, did not appear to be affected by age and sex: right ear advantage was predominant at all times. Individual comparison showed the development of ear advantage to depend on initial preference. Initially left eared subjects when changing ear advantage do so from left to right at early and from right to left at later school ages. The left-right shift may be due to the school teaching of linguistic skills which could selectively activate the left cerebral hemisphere. This explanation is supported by the finding that initially right eared subjects tended to conserve that preference at early school ages. Acknowledgements. We would like to thank Mr. P. Borgman and his staff of the Johannesschool in Amsterdam as well as their pupils who did not protest despite being examined year after year. The cooperation of the Free University Audio-Visual Center (Mr. Fred Van Hilst) is kindly acknowledged. Finally we would like to thank Dr. Paul Harris who was willing to read the English text critically and all others who assisted in the completion of this research.

Psychological effects of subclinical epileptiform EEG discharges. I. Scholastic skills.

The possible effects of subclinical epileptiform EEG discharges on educational skills have been studied. Twenty children with proven or suspected epilepsy and known subclinical EEG discharges underwent telemetric EEG and video monitoring during standard tasks of reading, mental arithmetic and manual dexterity, and at rest. The discharge rate was significantly lower at rest than during execution of a task. For both reading and arithmetic, the discharge rate was higher when the child was presented with material appropriate to his own level of ability than when easier or more difficult material was given. High discharge rates were associated with low test performance particularly for arithmetic. Reading speed was significantly increased during the discharges, but overall reading efficiency was significantly reduced with respect to the non-discharge condition. The decrement of reading efficiency was greater for longer than for shorter discharges. The findings confirm that otherwise subclinical EEG discharges may be accompanied by momentary impairment of scholastic skills. The interaction between discharges and cognitive function is, however, complex and the nature and level of difficulty of the task in turn affects the rate of EEG discharge.

Psychological effects of subclinical epileptiform EEG discharges in children. II. General intelligence tests.

Twenty-one children with suspected or proven epilepsy and subclinical epileptiform EEG discharges in the waking state were studied. The EEG was telemetered and behaviour recorded by closed-circuit television during performance of a general intelligence test (RAKIT, shortened version) which comprised 6 subtests. Mean total IQ was below that of control populations and the subtests profile was abnormal, due particularly to impaired performance on a subtest concerned with verbal short-term memory. This effect was accounted for by that subgroup of children who exhibited discharges during the test; those who did not show discharges at that time were unimpaired. Performance of 3 of the subtests was impaired when discharges occurred during presentation of the test item or between presentation and response. The findings suggest that cognitive impairment found in people with epilepsy may not only represent a more or less static disability, due to drugs, cerebral pathology, etc., but may in part be an intermittent process related to the occurrence of subclinical epileptiform discharges. These preliminary findings need to be amplified but have implications both for interpretation of neuropsychological studies in persons with epilepsy and also for the drug treatment of those who continue to exhibit subclinical EEG discharges when overt seizures have been controlled.

Hemispheric distribution of ERP components and word naming in preschool children.

Event-related potentials (ERPs) were recorded at the left and right temporal and parietal sites during a word-naming task in 61 children ranging in age from 5.1 to 6.2 years. Principal component analysis (PCA) was performed on the average ERP waveforms. Analyses of the factor scores revealed that the P240, N380, and SW components were asymmetrically distributed over the hemispheres. Fast reading acquisition was associated with smaller N380 and larger SW activity than slow reading acquisition. Multiple regression analyses indicated that only right hemispheric ERP components were significantly associated with rate of reading acquisition. These findings are discussed in terms of right hemispheric involvement in early reading acquisition.

Event-related potentials during word-reading and figure-matching in left-handed and right-handed males and females.

In two experiments, event-related potentials at left and right occipital, parietal, and temporal sites were studied in 16 left-handers (8 male, 8 female) and 16 right-handers (8 male, 8 female). Subjects displayed extreme handedness, had a normal writing hand position, reported no left-handed relatives, and reported no perinatal traumata. In Experiment 1, centrally presented words had to be read, and nonverbal stimuli had to be matched. Condition-dependent asymmetries were found for P340 and SW components. Word-reading elicited a N500 component, whereas figure-matching did not. In Experiment 2, words presented to either the left or right visual field had to be read. It was found that N160 measures were larger, and P240, P400, and SW measures were smaller to words presented in the contralateral visual field compared to words in the ipsilateral field. Sex affected these pathway effects. In both experiments, hand preference did not significantly influence the ERP results.

Skeletal muscle PO2 in anaerobic soft tissue infections during hyperbaric oxygen therapy.

In the present study skeletal muscle PO2 measurements were performed in patients with gas gangrene and anaerobic soft tissue infections before, during and after hyperbaric oxygen therapy. Polarographic PO2 needle electrodes appeared to be suitable for application during different ambient pressures. We found that patients with gas gangrene revealed higher skeletal muscle PO2 values than patients with an anaerobic soft tissue infection. This may be explained by a higher metabolic rate within the anaerobically infected soft tissues. The higher PO2 values in gas gangrene may be caused by alpha toxins, affecting cellular and intracellular membranes thus destroying PO2 diffusion barriers.

Red blood cell velocity in nailfold capillaries during hyperbaric oxygenation.

Microcirculatory hemodynamics of the skin during hyperbaric oxygenation were assessed by determination of nailfold capillary red blood cell velocity (Vrbc). Under hyperbaric conditions a continuous increase in Vrbc was found. Control values, 0.43 +/- 0.12 mm. sec-1 (mean +/- sem), were significantly (P < 0.05) lower compared with Vrbc at the end of hyperbaric oxygenation (0.62 +/- 0.16 mm.sec-1).

Treatment of chronic suppurative osteomyelitis of the mandible.

Chronic suppurative osteomyelitis of the mandible is often considered difficult to treat and may lead to refractory osteomyelitis. Sixteen patients with chronic suppurative osteomyelitis of the mandible were treated with a relatively simple protocol, consisting of sequestrectomy or decortication and i.v. antimicrobial therapy for one week, followed by oral penicillin for three weeks. Only one case showed recurrence of symptoms, which was treated successfully in a second session. It is concluded that combined surgical and antimicrobial therapy should be sufficient to cure most cases of chronic suppurative osteomyelitis of the mandible.

Hyperbaric oxygen treatment of osteoradionecrosis of the mandible. Experience in 29 patients.

In recent years hyperbaric oxygen has gained an important role in the treatment of osteoradionecrosis of the mandible. In the treatment of 29 patients with osteoradionecrosis of the mandible, a combination of surgical debridement, antibiotics, and hyperbaric oxygen was used in 27 cases. In 20 of the 29 patients the osteoradionecrosis was considered to be resolved after treatment. In 31% of the patients, the continuity of the mandible was lost. It was concluded that combined treatment of surgical debridement, antibiotics, and hyperbaric oxygen gives acceptable results and may, when used in an early phase of the disease, limit the number of patients who lose continuity of the mandible.

Consumer behaviour and attitudes towards low-calorie products in Europe.

A number of observations and conclusions can be made based on the data we have just seen: (1) There are large differences across the countries in terms of penetration of 'light' products. (2) The penetration of low-fat products is higher than that of low-sugar products. (3) Penetration of both low fat and low sugar products is higher among women than among men. (4) Penetration of both low-fat and low-sugar products is not dependent on age. (5) Consumption relates to penetration. (6) Consumer concerns about fat are greater than about sugar. (7) Consumer concerns about fat are at approximately the same level across Europe. (8) Concern about fat and sugar seems to increase with age. (9) Overweight is a problem for a third of the population across Europe. (10) Overweight is higher among men than among women. (11) Overweight increases with age.

Controlling persistent organic pollutants-what next?

Within the context of current international initiatives on the control of persistent organic pollutants (POPs), an overview is given of the scientific knowledge relating to POP sources, emissions, transport, fate and effects. At the regional scale, improvements in mass balance models for well-characterised POPs are resulting in an ability to estimate their environmental concentrations with sufficient accuracy to be of help for some regulatory purposes. The relevance of the parameters used to define POPs within these international initiatives is considered with an emphasis on mechanisms for adding new substances to the initial lists. A tiered approach is proposed for screening the large number of untested chemical substances according to their long-range transport potential, persistence and bioaccumulative potential prior to more detailed risk assessments. The importance of testing candidate POPs for chronic toxicity (i.e. for immunotoxicity, endocrine disruption and carcinogenicity) is emphasised as is a need for the further development of relevant SAR (structure activity relationship) models and in vitro and in vivo tests for these effects. Where there is a high level of uncertainty at the risk assessment stage, decision-makers may have to rely on expert judgement and weight-of-evidence, taking into account the precautionary principle and the views of relevant stake-holders. Close co-operation between the various international initiatives on POPs will be required to ensure that assessment criteria and procedures are as compatible as possible.

Neuropsychological classification and treatment of dyslexia.

Evidence shows that initial and advanced learning to read are predominantly mediated by the right and left cerebral hemispheres, respectively. Premature reliance on left-hemispheric reading strategies may result in L-type dyslexia, characterized by hurried and inaccurate reading. P-type dyslexia, characterized by a slow and fragmented style of reading, may result from the inability to shift from the predominant generation of right-hemispheric reading strategies to the predominant generation of left-hemispheric reading strategies. Results of investigations concerning the validity of the L/P-typology are discussed, as are the reading effects of hemisphere-specific and hemisphere-alluding stimulation in children with L- and P-type dyslexia.

Hemisphere-specific treatment of dyslexia subtypes: a field experiment.

Evidence is discussed to show that so-called L- and P-type dyslexia result from deviations in the development of hemispheric subservience in learning to read. Investigations into the validity of the L/P classification are reviewed, as are laboratory experiments on the effects of so-called hemisphere-specific stimulation (HSS). In the present field experiment, 28 L-dyslexic children (mean chronological and reading age 10.6 and 7.5 years, respectively) received HSS of the right hemisphere by the presentation of words to the fingers of the left hand, and 26 P-dyslexic children (mean chronological and reading age 9.4 and 7.2 years, respectively) received HSS of the left hemisphere by the presentation of words to the fingers of the right hand. Control L and P subjects were treated according to the discretion of the remedial teacher. The results underscore the findings of previous laboratory experiments in that (a) HSS-treated L-dyslexics, relative to controls, tended to show larger improvement of accuracy in text reading; and (b) HSS-treated P-dyslexics, relative to controls, showed larger improvement of fluency in word reading.

[Transthoracic esophagus transsection for bleeding esophageal varices (author's transl)]. / Ligatuur transsecties van de oesophagus abdominaal zowel als thoracaal.

The surgical treatment of bleeding esophageal varices is still controversial: the emergency shunt operation versus the so-called "sperr-operation". In the past three decennia, Boerema, of the department of surgery of the Wilhelmina Hospital in Amsterdam, has developed several types of ligation operations. In 1967 Boerema, Klopper and Holscher described the transabdominal oesophagus transsection using the Boerema-button for bleeding oesophageal varices (la Presse Médicale). This method has been used during ten years for 64 patients: the mortality was 39%. Since 1976 a new technique has been applied; the transthoracic oesophagus transsection. Up to the present, 7 patients have been operated upon, mortality was 14%. The technique and follow-up of both methods are discussed. We believe that the last method is a gain because of the simple technique, the esophagus does not need to be opened, so no contamination, limited operation-length, little loss of blood and prevention of laparatomy. Nevertheless one disadvantage exists: the method is suitable to esophageal varices, but not to gastric varices.

Economic impact of the CNS: practitioner role.

Documentation of the economic benefit of the CNS to the institution and consumer will be vital to help justify the position of the CNS within the evolving health care system. Two tools were developed and piloted to document and evaluate one of the CNS subroles that impacts nursing productivity and patient care outcomes. The practitioner subrole was evaluated by utilizing financial analysis. The rationale for selection of variables addressed within the tools are presented, and strengths and weaknesses of the tools and the implementation process are addressed. Quantification of the outcomes reflecting the cost effectiveness of the practitioner subrole is discussed.

Effective temperature of an ultracold electron source based on near-threshold photoionization.

We present a detailed description of measurements of the effective temperature of a pulsed electron source, based on near-threshold photoionization of laser-cooled atoms. The temperature is determined by electron beam waist scans, source size measurements with ion beams, and analysis with an accurate beam line model. Experimental data is presented for the source temperature as a function of the wavelength of the photoionization laser, for both nanosecond and femtosecond ionization pulses. For the nanosecond laser, temperatures as low as 14 ± 3 K were found; for femtosecond photoionization, 30 ± 5 K is possible. With a typical source size of 25 µm, this results in electron bunches with a relative transverse coherence length in the 10⁻4 range and an emittance of a few nm rad.