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Three moderator-type neutron survey instruments have been modelled for energy and angle dependence of the response, in greater detail than before. These response data have been verified by comparison with published experimental measurements and measurements made specifically for this project. Influences on the instrument response have also been investigated. These have included its mode-of-use and perturbations caused by variations in the instrument manufacture. The implications of these new response data have been assessed by an extensive programme of folding the responses with workplace energy distributions.

The performance of popular second moment closure (LRR, SSG) turbulence models is assessed and compared against experimental data for anisotropic swirling flow in a cylindrical combustion chamber. In contrast to previous studies, where the dissipation anisotropy is correlated with the stress anisotropy, the benefit of approximating the former for swirling flows in terms of the mean strain and vorticity is investigated. Second moment closure models are found to predict mean and turbulent flow quantities reasonably well everywhere except near the wall

The UK national standards laboratory, the National Physical Laboratory (NPL), provides an extensive range of facilities for measurements on neutron sources and neutron-sensitive devices. This paper describes recent improvements and extensions to the neutron standards. Correction factors used in source strength measurements have been improved, as have the scatter corrections used in monoenergetic and source-based irradiations. Characterisation of the thermal field facility has been improved by activation measurements. Experimental facilities developed recently include a system for measuring personal dosemeter responses at several energies simultaneously, and a neutron source tailored to simulate typical workplace fields.

High-resolution neutron energy spectra, covering the entire energy range of interest, for two standard radionuclide neutron sources ((241)Am-B and (241)Am-F) have been derived from Bonner sphere measurements by using high-resolution a priori data in the unfolding process. In each case, two a priori spectra were used, one from a two-stage calculation and also one from a combination of the calculated spectrum with a high-resolution measured spectrum. The unfolded spectra are compared with those published elsewhere and show significant differences from the ISO- and IAEA-recommended spectra for (241)Am-B and (241)Am-F, respectively. Values for the fluence-average energy and fluence-to-dose-equivalent conversion coefficients are presented for the new spectra, and the implications of the new spectra for the emission rates of the sources when measured by the manganese bath technique are also determined.

Wool fibres have been selectively stained in the region of the cell membrane complex with eosin Y, fluorescein and rose bengal. Dye distribution patterns were determined by fluorescence microscopy and electron-induced X-ray emission (in conjunction with scanning transmission electron microscopy). Irradiation of the stained fibres with visible light caused a reduction in the rate of dye uptake when the wool was subsequently treated with an aqueous solution of the dye CI Acid Red 18. The change in the dyeability of wool was attributed to selective photomodification of the cell membrane complex.

We tested the hypothesis that hypertension is more common and cardiac embolism less common in patients with lacunar infarction than in patients with other types of cerebral infarction. We studied risk factor profiles in a series of 102 consecutive patients with a lacunar infarct and 202 consecutive patients with a carotid artery-distribution infarct involving the cortex registered in the Oxfordshire Community Stroke Project, a community-based study of first-ever stroke. The two groups did not differ in the prevalence of prestroke hypertension (defined in a number of ways) or in the prevalence of markers of sustained hypertension. The presence of atrial fibrillation and a history of myocardial infarction, particularly during the 6 weeks before the stroke, were significantly more common in the group with carotid-distribution infarcts involving the cortex. There was no significant difference in the prevalence of other accepted risk factors for ischemic stroke, including previous transient ischemic attack, cervical bruit, diabetes mellitus, peripheral vascular disease, or cigarette smoking. Our results suggest that hypertension is no more important in the development of lacunar infarction than it is in the development of other types of ischemic stroke that are presumed to be due to atherosclerotic thromboembolism in a major cerebral artery. Our data support the autopsy evidence that cardioembolic occlusion is an unusual cause of lacunar infarction.

One of the most common radionuclide neutron sources used for the calibration of detectors is (252)Cf. However, these sources also contain (250)Cf, which is present in the material from which the sources are made, and (248)Cm, which is formed as the daughter of (252)Cf via alpha-decay. Both decay by spontaneous fission with longer half-lives than (252)Cf. Consequently, as the source becomes older, the emission rate does not follow the decay curve of (252)Cf. Fits have been made to emission rate measurements of (252)Cf sources at NPL spanning over 30 y to deduce their (250)Cf and (248)Cm content. The emission rate of a source can be significantly underestimated if the presence of (250)Cf and (248)Cm is not taken into account, and this has been investigated for a typical (252)Cf source. The importance of this problem to other calibration laboratories and users of (252)Cf sources is emphasised.

Bonner sphere (BS) sets which use activation foils as the central thermal neutron sensor have advantages over active BS systems in certain environments, for example, pulsed fields, or fields with high photon components. In such environments, they may be the only type of neutron spectrometer which can be used. This paper describes work, using both measurements and calculations, to validate the response functions for a BS set based on gold activation foils. As an illustration of the use of such a system, a measurement is described of the contaminant neutron spectrum in the treatment room of a 21 MV hospital linear accelerator providing photon beams for radiotherapy.

Improvements have been made to the Monte Carlo modelling used to calculate the response of the neutron survey instruments most commonly used in the UK, for neutron energies up to 20 MeV. The improved modelling of the devices includes the electronics and battery pack, allowing better calculations of both the energy and angle dependence of response. These data are used to calculate the response of the instruments in rotationally and fully isotropic, as well as unidirectional fields. Experimental measurements with radionuclide sources and monoenergetic neutron fields have been, and continue to be made, to test the calculated response characteristics. The enhancements to the calculations have involved simulation of the sensitivity of the response to variations in instrument manufacture, and will include the influence of the user and floor during measurements. The practical implications of the energy and angle dependence of response, variations in manufacture, and the influence of the user are assessed by folding the response characteristics with workplace energy and direction distributions.

An alternative to using hair specimens for the study of inherited hair shaft defects has been to explore protein compositions in the context of hair formation. Hair follicles were obtained from patients with a hair disorder and the presumptive hair shaft (PHS) separated by microdissection for protein solubilization and electrophoretic experiments aimed at providing a new basis to help explain the mechanism of hair shaft defects. Two-dimensional electrophoresis (fluorographs) of labelled extracts was used to examine the major hair structural proteins and other polypeptide(s) found associated with PHS extracts in normal and aberrant specimens. Changes in either the intermediate filaments (IFs) or matrix polypeptides were not normally found in defective PHS specimens. The polypeptides showing greatest variation were associated with a PHS-specific component which was recently found in normal specimens. The variation in this polypeptide was manifested as multiple spots of different molecular weights. An investigation of the role of PHS-associated polypeptides as a likely part of the hair cross-linking mechanisms, involved examination of a PHS extract from a Menkes' patient. The observations suggest that formation of hair fibre shaft defects may be related to the status of PHS-associated polypeptides which could in turn be influenced by the presence of copper in the hair follicle.

Section III (neutron measurements) of the Comite Consultatif des Rayonnements Ionisants, CCRI, conducted a key comparison of primary measurements of the neutron emission rate of an 241 Am-Be(α,n) radionuclide source. A single 241 Am-Be(α,n) source was circulated to all the participants between 1999 and 2005. Eight laboratories participated – the CIAE (China), CMI (Czech Republic), KRISS (Republic of Korea), LNMRI (Brazil), LNE-LNHB (France), NIST (USA), NPL (UK), and the VNIIM (Russian Federation) – with the NPL making their measurements at the start and repeating them near the end of the exercise to verify the stability of the source. Each laboratory reported the emission rate into 4π sr together with a detailed uncertainty budget. All participants used the manganese bath technique, with the VNIIM also making measurements using an associated particle technique. The CMI, KRISS, VNIIM, and later the NPL, also measured the anisotropy of the source although this was not a formal part of the comparison. The first draft report was released in May 2006 and having been discussed and modified by the participants and subsequently reviewed by the CCRI(III), the present paper is now the final report of the comparison.

A total of 323 cases of first-ever stroke were registered in the first 2 years of the Oxfordshire Community Stroke Project. Of these patients, 244 (76%) had a stroke due to cerebral infarction. There was a past history of migraine headaches in 56 (17%) of the 323 cases of stroke and in 44 (18%) of the 244 cases of cerebral infarction. A past history of migraine headaches was no commoner in patients with stroke due to cerebral infarction than in those with stroke due to intracranial haemorrhage. One hundred and seventy-three (71%) patients with cerebral infarction had at least one risk factor for ischaemic stroke; the frequency of such risk factors was similar in patients with and without a history of migraine. In 7 (3%) of the 244 patients the cerebral infarction was presumed to be "migrainous"; however, only 3 of these 7 (1.2% of the 24) were free of risk factors for ischaemic stroke. If all 7 cases were considered migrainous, the incidence rate of first migrainous cerebral infarction was 3.36 per 100,000 per year (95% confidence limits 0.87-5.86). If only the 3 patients who were free of risk factors were included, the incidence was 1.44 per 100,000 per year (95% confidence limits 0-3.07).

In a consecutive series of 515 first-ever strokes in a community-based study of stroke that combined prompt clinical assessment by a study neurologist with a high rate of confirmed pathologic diagnosis, 108 cases (21%) had a lacunar syndrome. A computed tomography (CT) scan was performed in 104 (96%) of these cases. Only 3 cases had primary intracerebral hemorrhage, and another 3 had "inappropriate" areas of infarcts were seen in 34 of the remaining 98 (35%) CT scans. The crude annual incidence of lacunar infarction was 0.33/1,000. There was no excess risk among men. The case fatality rates were 1% at 1 month and 9.8% at 1 year. The rate of recurrent strokes was 11.8% in the first year. Among patients surviving 1 year, 66% were capable of independent existence.

We used developing human hair follicle cells for the isolation of hard alpha-keratin structural components. Intracellular dispersions examined by electron microscopy contained both individual alpha-keratin filaments and the tactoid-like filament assemblies observed in situ organized along subfibrillar arms of macrofibrils. The assemblies of average width 47 nm were composed of closely packed alpha-keratin filaments and originated from the initial filament arrays observed in sections of developing mammalian hair follicles. We have distinguished two types of assemblies: the para-like or hexagonally packed and the ortho-like spiral or whorl type. Axial banding extended across the width of filament assemblies, which suggested that hard alpha-keratin filaments pack in lateral register and form a lattice that contains interfilamentous bridges. We observed axial banding patterns with periods ranging from 20 to 22 nm, consistent with the 22-nm periodic structure deduced from x-ray diffraction studies and present in models proposed for hard alpha-keratin and other intermediate filaments. Preliminary biochemical studies of filaments and filament assemblies indicate that they consist of the closely related group of proteins (low-sulfur proteins) ubiquitous among extracts of hard mammalian keratins. Isolated hard alpha-keratin filament assemblies provide a new and valuable structural entity for investigating the assembly mechanisms involved in the formation of the filament-matrix framework found in hard mammalian keratin appendages.

Hypertension is a major public health problem affecting 20 to 30 million people in the United States, many of whom are undetected, untreated, or inadequately treated. Because hypertension often is asymptomatic for decades, it must be systematically sought out in apparently well persons if the condition is to be treated in its earliest stages and complications prevented. With the recent advent of effective antihypertensive medications treatment is available, once the patient has been diagnosed. Physicians and nurses have a major responsibility to direct the patient into treatment and to assure the effectiveness of his follow-up care. Noncompliance is a direct challenge to everyone seeing the patient. The patient must be motivated to accept and continue therapy through education and, most important, by the establishment of a good interpersonal relationship with the nurse and/or the physician.