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.

High-coherence electron bunches produced by femtosecond photoionization.

With the development of ultrafast electron and X-ray sources it is becoming possible to study structural dynamics with atomic-level spatial and temporal resolution. Because of their short mean free path, electrons are particularly well suited for investigating surfaces and thin films, such as the challenging and important class of membrane proteins. To perform single-shot diffraction experiments on protein crystals, an ultracold electron source was proposed, based on near-threshold photoionization of laser-cooled atoms, which is capable of producing electron pulses of both high intensity and high coherence. Here we show that high coherence electron pulses can be produced by femtosecond photoionization, opening up a new regime of ultrafast structural dynamics experiments. The transverse coherence turns out to be much better than expected on the basis of the large bandwidth of the femtosecond ionization laser pulses. This surprising result can be explained by analysis of classical electron trajectories.

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.

Hyperbaric oxygen therapy and the diabetic foot.

Common causes for non-healing of diabetic foot ulcers are infection and/or ischaemia. Diabetic patients are compromised hosts as far as wound healing is concerned. Diabetes mellitus is associated with a defective cellular and humoral immunity. In particular, decreased chemotaxis, decreased phagocytosis, impaired bacterial killing and abnormal lymphocytic function have been observed, resulting in a reduced inflammatory reaction and defective wound healing. The potential benefits of hyperbaric oxygen therapy (HBO) in diabetic patients with a foot ulcer are discussed. Oxygen plays an important role in the physiology of wound healing. HBO can raise tissue oxygen tensions to levels where wound healing can be expected. Hyperbaric oxygen increases also the killing ability of leucocytes, is lethal for certain anaerobic bacteria and inhibits toxin formation in other anaerobes. Multiple anecdotal reports and retrospective studies in HBO therapy in diabetic patients suggest that HBO can be an effective adjunct in the management of diabetic wounds. Prospective studies also show the beneficial effects of HBO. Because most published studies suffer from methodological problems, there is an urgent need for a collaborative, international, randomised prospective clinical trial for the application of HBO in diabetic foot lesions, as part of a multidisciplinary treatment approach, before we can recommend HBO as standard therapy in patients with foot ulcers.

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.

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 for haemorrhagic radiation cystitis.

Radiation-induced severe haemorrhagic cystitis is difficult to treat. Conventional treatments may decrease haematuria but do not affect the radiocystitis itself. Hyperbaric oxygen treatment has been reported to do both. We report the results of a prospective study of hyperbaric oxygen (20 sessions of 100% oxygen inhalation at 3 bar for 90 min in a multiplace hyperbaric chamber) to 40 patients with biopsy-proven radiation cystitis and severe haematuria. Haematuria disappeared completely or improved in 37 patients after treatment. Mean follow-up was 23.1 months (range 1-74); and the recurrence rate was 0.12/year. There were no adverse effects. Hyperbaric oxygen treatment should be considered for patients with severe radiation-induced haematuria.

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.

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.

Dyslexia and the ecological brain.

Evidence is available to show that normal and disturbed reading is a bilateral rather than an unilateral hemispheric affair. The primary subservience of reading seems to shift from right to left during the development of the learning-to-read process. Since the brain is sensitive to enriched stimulation from the environment, hemisphere-tied dyslexia may be alleviated by selective or alluding stimulation of the right (L-dyslexia) or the left (P-dyslexia) cerebral hemisphere. In general, the results of experimental group and single-case investigations show the fruitfulness of these neuropsychological treatment procedures. However, it is apparent that there are questions that remain to be answered.

Hyperbaric oxygen treatment of osteoradionecrosis of the mandible with repeated pathologic fracture. Report of a case.

Treatment of patients with osteoradionecrosis of the mandible with a pathologic fracture consists in almost all cases of a continuity resection of the mandible. This leads to functional and esthetic problems that can only be solved by often extensive surgery. In this case report we present a 38-year-old woman who developed osteoradionecrosis of the mandible with a pathologic fracture 1 1/2 years after combined surgical and radiation therapy of an adenocarcinoma of the right parotid gland. The patient had a subcondylar pathologic fracture together with osteolysis in the right mandibular body, normally an indication for partial resection of the mandible. Because of the absence of denuded bone, fistulation, and the poor quality of the surrounding soft tissues, a more conservative approach was chosen. Treatment consisted of hyperbaric oxygen and dental extractions with alveolectomy with the patient under local anesthesia. During follow-up, a second pathologic fracture occurred in the region of the right first and second molar. No additional treatment was given. Six and one-half years after the initial treatment and 5 1/2 years after the last fracture, the patient is free of complaints, the fractures have healed and both esthetic and functional results are good.

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).