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The National Radiological Protection Board (NRPB) has recommended the introduction of dose-width product (DWP) for the measurement of patient dose in panoramic dental radiology and has proposed a reference level of 65 mGy mm for adult exposures. This paper describes a method for measuring DWP and dose-area product (DAP) using thermoluminescent dosemeters (TLDs). The technique was used on 16 sets with a range of exposure settings. The mean value of DWP was 14% higher than the mean value reported from a survey by the NRPB. This difference is most likely to be caused by systematic variations due to measurement method. The average DAP for a standard adult examination was shown to be 11.3 cGy cm2. Data are presented so that the DAP can be derived from the exposure factors (tube current and operating potential) and beam area. Based on published data for effective dose, it is estimated that the DAP to effective dose conversion factor is approximately 0.06 mSv(Gy cm2)-1. The average DAP value (11.3 cGy cm2) can be compared with the average value for intraoral radiography (9.3 cGy cm2) based on the NRPB survey of entrance surface doses assuming 6 cm circular collimation.

We assessed the inter- and intraobserver variation in classification systems for fractures of the distal humerus. Three orthopaedic trauma consultants, three trauma registrars and three consultant musculoskeletal radiologists independently classified 33 sets of radiographs of such fractures on two occasions, each using three separate systems. For interobserver variation, the Riseborough and Radin system produced 'moderate' agreement (kappa = 0.513), but half of the fractures were not classifiable by this system. For the complete AO system, agreement was 'fair' (kappa = 0.343), but if only AO type and group or AO type alone was used, agreement improved to 'moderate' and 'substantial', respectively (kappa = 0.52 and 0.66). Agreement for the system of Jupiter and Mehne was 'fair' (kappa = 0.295). Similar levels of intraobserver variation were found. Systems of classification are useful in decision-making and evaluation of outcome only if there is agreement and consistency among observers. Our study casts doubt on these aspects of the systems currently available for fractures of the distal humerus.

We present the jump conditions for ionization fronts with oblique magnetic fields. The standard nomenclature of R- and D-type fronts can still be applied, but in the case of oblique magnetization there are fronts of each type about each of the fast- and slow-mode speeds. As an ionization front slows, it will drive first a fast- and then a slow-mode shock into the surrounding medium. Even for rather weak upstream magnetic fields, the effect of magnetization on ionization front evolution can be important. [Includes numerical MHD models and an application to observations of S106.], 9 pages, 10 figures, Latex, to be published in MNRAS

Over the past decade there has been an increased number of llamas and alpacas raised in North America, with a heavy concentration in the Northwest. This increase serves as an impetus for studying the comparative features of the South American camelids in relation to our domestic animal species. The llama and the alpaca occupy a unique epidemiological position between members of the equine and bovine species in terms of their susceptibility to infectious agents that are known to infect either horses and/or cattle. 9,10,12,13 This report describes the isolation of a virus with in vitro properties of bovine herpesvirus type 1 (BHV-1), infectious bovine rhinotracheitis (IBR), from the lungs of a llama with bronchopneumonia. The subject was a 3-year-old female llama in the later stages of pregnancy that had a 2-month history of a productive cough and gradual weight reduction. The vaccination history indicated the use of an 8-way clostridial bacterin but no use of viral vaccines. The llama was presented live to the clinic and was anorexic and recumbent. A tracheal wash was performed for bacterial and viral culture and a blood sample obtained for serology. Within 1 day of admittance to the clinic, the llama died. A postmortem examination revealed gross lesions confined to the pleural cavity. The lungs appeared congested and hemorrhagic with small bronchi filled with clotted blood and a bloody froth within the trachea and esophagus. Samples collected at necropsy for laboratory diagnostic procedures included fluid from the pericardial sac and fresh and fixed portions of the lungs, heart, and kidney. Formalin-fixed sections of lung, kidney, and heart were stained with hematoxylin and eosin for routine evaluation. The Brown and Brenn stain was used to evaluate selected sections for the presence of bacteria. Histology of the tissues revealed lesions confined to the lung. A few randomly scattered alveoli contained low numbers of degenerating neutrophils and foamy macrophages. Some of the adjacent bronchioles also contained clumps of degenerating neutrophils and cell debris. Moderate diffuse congestion was present. No inclusion bodies or bacteria were noted in the sections observed. The histologic changes in the lung were regarded as mild and acute and did not explain the death of the llama. The pulmonary changes were reflective of an early inflammatory response compatible with a bacterial infection. The morphologic diagnosis was an acute, mild, multifocal neutrophilic bronchopneumonia consistent with an early inflammatory response to a bacterial infection. The samples collected antemortem and at postmortem were

To describe the role of the Internet in building virtual communities of doctors, to identify threats to privacy and confidentiality in this use of the Internet, and to suggest ways in which this threat can be managed.The Internet is revolutionizing the medical profession. The doctor's role as medical expert is being challenged by patients who have immediate access to multiple sources of information about their diseases. Telemedicine makes use of the Internet to enable doctors to diagnose and treat patients far from their offices or hospitals. Internet list servers and chat groups gather doctors together in virtual space to exchange views on clinical and professional issues. This paper focuses on the last of these Internet applications, beginning with a description of the 'virtual community' that the list servers and chat groups constitute. It demonstrates how various Internet practices particular to virtual communities, namely registration, e-mail lists, and 'cookies', pose a threat to confidentiality. It discusses the conflicting values at stake, especially privacy and confidentiality on the one hand and openness and freedom on the other, and suggests how a balance between these can be achieved.The proposed resolution of the value conflict necessitates the implementation of effective registration systems, including collection of participants' personal information, and the monitoring of submissions to the chat groups. At the same time, the privacy (anonymity) of participants is maintained, except to the monitor, and the latter can intervene to delete uncivil submissions. Participants are also protected against unauthorised use of their e-mail addresses for advertising purposes and the like.

This study compared the effects of centrally administered oxytocin (OT) and arginine vasopressin (AVP) on partner preference formation and social contact in male and female prairie voles (Microtus ochrogaster). After 1 hr of cohabitation and pretreatment with either AVP or OT, both males and females exhibited increased social contact and significant preference for the familiar partner. After pretreatment with either an OT receptor antagonist (OTA) or an AVP (V1a) receptor antagonist (AVPA), neither OT nor AVP induced a partner preference. In addition, treatment with OT+OTA or AVP+AVPA was associated with low levels of social contact in both sexes. Either AVP or OT is sufficient to facilitate social contact if either the OT or AVP receptor is available. However, the formation of partner preferences may require access to both AVP and OT receptors.

The neuron-specific K-Cl cotransporter (KCC2) is hypothesized to function as an active Cl- extrusion pathway important in postsynaptic inhibition mediated by ligand-gated anion channels, like gamma-aminobutyric acid type A (GABAA) and glycine receptors. To understand better the functional role of KCC2 in the nervous system, we developed polyclonal antibodies to a KCC2 fusion protein and used these antibodies to characterize and localize KCC2 in the rat cerebellum. The antibodies specifically recognized the KCC2 protein which is an approximately 140-kDa glycoprotein detectable only within the central nervous system. The KCC2 protein displayed a robust and punctate distribution in primary cultured retinal amacrine cells known to form exclusively GABAAergic synapses in culture. In immunolocalization studies, KCC2 was absent from axons and glia but was highly expressed at neuronal somata and dendrites, indicating a specific postsynaptic distribution of the protein. In the granule cell layer, KCC2 exhibited a distinct colocalization with the beta2/beta3-subunits of the GABAA receptor at the plasma membrane of granule cell somata and at cerebellar glomeruli. KCC2 lightly labeled the plasma membrane of Purkinje cell somata. Within the molecular layer, KCC2 exhibited a distinctly punctate distribution along dendrites, indicating it may be highly localized at inhibitory synapses along these processes. The distinct postsynaptic localization of KCC2 and its colocalization with GABAA receptor in the cerebellum are consistent with the putative role of KCC2 in neuronal Cl- extrusion and postsynaptic inhibition.

Reactive oxygen intermediates (ROIs) are important signals controlling cell growth and cell death. Local essential fatty acid (EFA) deficiencies in tumour cells may limit tumour ROI generation. This deficiency may be rectified by the addition of exogenous EFA.The n-6 EFA effects on tumour ROIs were analysed in terms of kinetics, dose-response and individual cell type responses using flow cytometry of intracellular 2',7'-dichlorofluorescin oxidation. ROI formation in 30 gliomas and five paired samples of normal brain tissue,500 000 cells per specimen, was analysed every 10 s for 0-25 min.Tumour cell basal ROI was lower than normal brain tissue ROI from the same subjects (P0.00002). Normal and tumour cell ROIs were stimulated by 4-40 micromol L-1 n-6 EFAs, arachidonic acid (AA) and gamma-linolenic acid (GLA). The stimulated ROI rate was exponential, with the maximum dependent on EFA concentration and tumour grade.EFAs stimulated tumour cells more than normal cells (P0.0000017, n = 71) and increased ROIs in glial fibrillary acidic protein-positive cells in tumours. This indicated high sensitivity of glioma cell ROIs to n-6 EFAs.

Human lung cancer cells, including small cell lung carcinoma (SCLC), frequently lose expression of retinoic acid receptor beta (RAR-beta) and are resistant to the growth inhibitory activity of all-trans retinoic acid (RA). To elucidate the role of RAR-beta in the growth regulation of SCLC by retinoids, we restored RAR-beta expression in RAR-beta-negative H209 SCLC cells by retroviral transduction (H209-RAR-beta). We found that H209-RAR-beta, but not parental H209 cells, underwent growth inhibition upon RA treatment. RA-treated H209-RAR-beta cells arrested in G1 and displayed reduced L-myc expression and cyclin-dependent kinase 2 (cdk2) activity compared with untreated cells. RA treatment of H209-RAR-beta cells was also accompanied by increased expression of the cdk inhibitor p27Kip1, whereas no differences in the expression of L-myc or p27Kip1 were detected upon RA treatment of parental H209 cells. The RA-induced growth arrest of H82 SCLC cells, which express endogenous RAR-beta, was also associated with reduced c-myc and increased p27Kip1 expression. We found that ectopic expression of p27Kip1 induced growth inhibition in both H209 and H82 cells, and that sustained myc expression in H209-RAR-beta cells promoted the induction of apoptosis upon RA addition. Our observations indicate that RAR-beta gene transfer can restore RA sensitivity in SCLC cells and suggest that myc and p27Kip1 may represent critical mediators of the RA-induced cell cycle arrest in SCLC cells expressing RAR-beta.

In this paper we discuss our recent efforts to update the X-ray treatment of grains in the PDR modeling code Cloudy.

Prostate cancer is the most commonly diagnosed neoplasm in men. LNCaP cells continue to possess many of the molecular characteristics of in situ prostate cancer. These cells lack ras mutations, and mitogen-activated protein kinase (MAPK) is not extensively phosphorylated in these cells. To determine the effects of ras/raf/MAPK pathway activation in these cells, we transfected LNCaP cells with an activatable form of c-raf-1(deltaRaf-1:ER). Activation of deltaRaf-1:ER, with resultant MAPK activation, reduced plating efficiency and soft agarose cloning efficiency 30-fold in LNCaP cells. Cell cycle distribution showed an accumulation of cells in G1 and was associated with the induction of CDK inhibitor p21WAF1/CIP1 at the protein and mRNA levels. p21WAF1/CIP1 mRNA stability was increased after deltaRaf-1:ER activation. In addition, activated deltaRaf-1:ER induced the senescence associated-beta-galactosidase in LNCaP cells. These data demonstrate that raf activation can activate growth inhibitory pathways leading to growth suppression in prostate carcinoma cells and also suggest that raf/MEK/MAPK pathway activation, rather than inhibition, may be a therapeutic target for some human prostate cancer cells.

Clinical modulation of radiosensitivity via combined fractionated high dose rate and continuous ultra-low dose rate irradiation (ULDR) holds promise for the radiosensitization of human malignant gliomas. We measured both the in vitro and in vivo responses of a human malignant glioma cell line to combined continuous ULDR and high dose rate treatments. For in vitro ULDR treatments, U251 human malignant glioma cells were cultured in media containing tritiated water to yield a continuous dose rate of 0.03 Gy/hr. After exposures of 24, 48, or 72 hr, cells were acutely (1.1 Gy/min) irradiated, replated, and scored for colony formation. In vivo, U251 flank xenografts in nude mice had 125-iodine (125-I) seed brachytherapy at a dose rate of 0.05 Gy/hr. For whole-body continuous ULDR (0.03 Gy/hr), a 137-Cs source was mounted a fixed distance above the cages of animals bearing xenografts. After 3 days' continuous exposure, xenografts were acutely irradiated (2 Gy x 8 vs. 5 Gy x 2 daily fractions), and the regrowth delay in tumors was measured. In vitro, exposure to ULDR (0.03 Gy/hr) alone caused only modest killing and reduced the surviving fraction by approximately 0.2 logs after 72 hr exposure. The highest (10 Gy) dose of acute irradiation alone reduced survival by 1 log. However, U251 cell killing increased to 2.5 logs after combined HDR and ULDR treatments. Linear-quadratic modeling showed comparatively greater increase in the beta than the alpha coefficients of the linear-quadratic model for cell killing. In vivo, the 125-I seed brachytherapy treatments delayed tumor growth but resulted in no regression. The HDR treatments (5 Gy x 2 or 2 Gy x 8 daily fractions) caused growth delays (in days) of 17+/-2 or 16+/-2 (P=NS) days, respectively. The combined seed and 5 Gy x 2 or 2 Gy x 8 daily fractions regimen resulted in striking prolongation of regrowth delay (52.3+/-8.7 vs. 59.5+/-7.7 days) (P0.001 vs. HDR treatments alone). External ULDR alone caused no regression and minimal growth delay. Combined continuous external ULDR and the 5 Gy x 2 vs. 2 Gy x 8 daily fraction regimens resulted in prolongation of growth delay (33+/-0.9 (P=0.01 vs. 5 Gy x 2 daily fractions alone) vs. 35+/-0.7 (P=0.049 vs. 2 Gy x 8 daily fractions alone). We conclude that continuous ULDR increases the effect of HDR treatments of experimental malignant glioma. This increased effect may prove clinically important in the treatment of human malignant brain tumors.

This paper presents an application of large-eddy simulation (LES) to spatially developing isothermal and buoyant jets. The numerical method is based on the predictor-corrector approach for low Mach number compressible flows. The Adams-Bashforth scheme is used for time marching integration and a QUICK difference is used for space discretization on a staggered grid for the 3D Navier-Stokes equations.

Since 1994 the DNS-Turbulence Consortium has been using the Cray T3D and T3E computers at Edinburgh Parallel Computing centre to conduct space-and time-resolved calculations of turbulent flow. A variety of cases have been studied in detail including the first resolved calculation of turbulent boundary layer reattachment following laminar separation, the response of turbulence to three-dimensional distortion and the response of turbulence to separation. The data from these simulations have been used to test and improve turbulence models. In this paper the progress that has been made in the last three years is reviewed.

Expression of the genes for the membrane-bound Fo sector of the Escherichia coli F1Fo proton-translocating ATPase can respond to changes in metabolic conditions, and these changes are reflected in alterations in the subunit stoichiometry of the oligomeric Fo proton channel. Transcriptional and translational lacZ fusions to the promoter and to two Fo genes show that, during growth on the nonfermentable carbon source succinate, transcription of the operon and translation of uncB, encoding the a subunit of Fo, are higher than during growth on glucose. In contrast, translation of the uncE gene, encoding the c subunit of Fo, is higher during growth on glucose than during growth on succinate. Translation rates of both uncB and uncE change as culture density increases, but transcription rates do not. Quantitation of the c stoichiometry shows that more c subunits are assembled into the F1Fo ATPase in cells grown on glucose than in cells grown on succinate. E. coli therefore appears to have a mechanism for regulating the composition and, presumably, the function of the ATPase in response to metabolic circumstances.

During a 9-year period, 15 patients with hemochromatosis hip arthropathy required 19 total hip arthroplasties for disabling hip pain. Preoperative presentation, hip function, pathologic evaluation of the femoral head, and radiographic findings were reviewed. Postoperative followup averaging 5.7 years (range, 2-11 years) was performed to assess hip pain and function after total hip arthroplasty. The average preoperative Hospital for Special Surgery hip score was 15 points (range, 4-24 points), and this improved to 30 points (range, 4-38 points) after total hip arthroplasty. Only one of 15 patients required revision surgery at 10 years for acetabular loosening. All other patients were pain free, with improved function at latest followup. Histologic evaluation of the resected femoral heads revealed evidence of primary or secondary osteonecrosis in seven of 19 (37%) specimens. Articular cartilage avulsion at the level of the tidemark was identified in eight of 19 (42%) specimens, and calcium pyrophosphate deposition was identified in five of 19 (26%) specimens. These pathologic findings suggest a predictable progression of the arthritic process in patients with hemochromatosis.

There are many challenges to be met when writing an introductory treatise on an academic topic. The subject matter must be presented in a simple but not oversimplified manner. Enough theory must be included to ground the discussion of specific issues but not so much as to overwhelm or bore the readers. The text should be long enough to do justice to the subject matter but short enough to be readily accessible, especially for readers such as healthcare professionals, whose primary concerns lie elsewhere. There are additional challenges in a relatively novel interdisciplinary field such as bioethics. The scope and methodology of bioethics are matters of great controversy, as are its relations with related subjects such as professionalism and human rights. The field is so broad that a single author cannot claim expertise on all topics. Rivalries between law and ethics and among medicine, other health professions, and disciplines such as philosophy complicate efforts to produce a broadly acceptable text. Finally, national and cultural differences pose major challenges to anyone trying to write for a truly international readership. The difficulty of meeting all these challenges in producing the WMA Medical Ethics Manual provides ample opportunity for criticism, especially from bioethics experts. The three expert reviewers of the manual in this issue of the journal are remarkably restrained in pointing out its shortcomings.1–3 I am grateful for both their positive evaluations and their constructive criticism. In what follows, I will respond to each of them in turn, focusing in particular on their suggestions as to how the Manual could have been improved. Before addressing these suggestions, I wish to clarify a matter raised by Soren Holm, namely, to what degree the manual …

We study the kinematical and brightness evolution of emission line clouds in the narrow line region (NLR) of Seyfert galaxies during the passage of a jet. We derive a critical density above which a cloud remains radiative after compression by the jet cocoon. The critical density depends mainly on the cocoon pressure. Super-critical clouds increase in emission line brightness, while sub-critical clouds generally are highly overheated reducing their luminosity below that of the inter-cloud medium. Due to the pressure stratification in the bow-shock of the jet, a cylindrical structure of nested shells develops around the jet. The most compact and brightest compressed clouds surround the cloud-free channel of the radio jet. To support our analytical model we present a numerical simulation of a supersonic jet propagating into a clumpy NLR. The position-velocity diagram of the simulated H_alpha emission shows total line widths of the order of 500 km/s with large-scale variations in the radial velocities of the clouds due to the stratified pressure in the bow-shock region of the jet. Most of the luminosity is concentrated in a few dense clouds surrounding the jet. These morphological and kinematic signatures are all found in the well observed NLR of NGC1068 and other Seyfert galaxies., 11 pages, 3 figures, accepted for publication in The Astrophysical Journal Letters

The Fe unresolved transition array (UTAs) produce prominent features in the 15-17?A wavelength range in the spectra of Active Galactic Nuclei (AGN). Here we present new calculations of the energies and oscillator strengths of inner- shell lines from Fe XIV, Fe XV, and Fe XVI. These are crucial ions since they are dominant at inflection points in the gas thermal stability curve, and UTA excitation followed by autoionization is an important ionization mechanism for these species. We incorporate these, and data reported in previous papers, into the plasma simulation code Cloudy. This updated physics is subsequently employed to reconsider the thermally stable phases in absorbing media in Active Galactic Nuclei. We show how the absorption profile of the Fe XIV UTA depends on density, due to the changing populations of levels within the ground configuration., ApJ in press

We present non-adiabatic hydrodynamic simulations of a supersonic light jet propagating into a fully ionized medium of uniform density on a scale representative of the narrow line region (NLR) in Seyfert galaxies with associated radio jets. In this regime the cooling distance of the swept up gas in the bowshock of the jet is of the same order as the transverse extent of the jet bowshock, as opposed to the more extreme regimes found for more powerful adiabatic large scale jets or the slow galactic jets which have been simulated previously. We calculate the emissivity for the H_alpha line and radio synchrotron emission. We find that the structure of the line emitting cold envelope of the jet cocoon is strongly dependent on the non-stationary dynamics of the jet head as it propagates through the ambient medium. We observe the formation of cloud-like high density regions which we associate with NLR clouds and filaments. We find that some of these clouds might be partially neutral and represent sites of jet induced star formation. The calculated H_alpha flux and the spectral line width are consistent with NLR observations. The simulation of the radio-optical emission with radiative cooling confirms the basic result of the geometric bowshock model developed by Taylor et al. (1989) that the start of noticeable optical line emission can be significantly offset from the hotspot of the radio emission. However, the time-dependent nature of the jet dynamics implies significant differences from their geometric bowshock model., 11 pages, 5 figures, accepted for publication in MNRAS

Reactive oxygen intermediate (roi) generation was investigated in phagocytes of 39 patients undergoing pulmonary resection for lung cancer and 39 paired healthy controls. Generation of roi in monocytes and neutrophils was monitored using 2',7'-dichlorofluorescin diacetate. Activation associated with hydrophobic interactions was probed by analysis of phagocyte roi activation by arachidonic acid and gamma-linolenic acid. Patient roi was measured pre-operatively and 2 and 7 days post-operatively. Elevated (P0.01) roi production was detected in neutrophils of lung cancer patients. Surgery was associated with an increase (P0.05-P0.01) in phagocyte roi at 2 and 7 days post-op. Phagocyte roi was stimulated by arachidonic acid and gamma-linolenic acid (1-40 microM) both pre- and post-operatively. Differences in arachidonic acid and gamma-linolenic acid stimulation between patient and control and pre- and post-op patient phagocytes suggest arachidonic acid involvement in phagocyte activation during reactive responses to lung carcinoma and surgery.

When regional health boards choose how to allocate limited resources on the public's behalf, they are exercising ethical judgment. When board members are familiar with the study of ethics and the tools it has produced, they are able to make informed and consistent ethical choices. One board in P.E.I. drew upon ethical principles to first codify its core values, and then develop a process for making decisions which conformed to those values. As boards across Canada assume greater authority and responsibility for public health, a clear understanding of ethical principles can guide their difficult choices.

As health care systems undergo funding cutbacks, we cannot expect to receive all needed and wanted health care services at public expense. Instead, choices must be made about which services will be provided from public funds (and to whom), which will be available to individuals who wish to purchase them, and which will not be available at all. These are ethical questions, if only because the proposed answers will reflect different concepts of social justice. This article identifies and describes some of the major ethical considerations in redefining the principle of "comprehensiveness" in the Canada Health Act. The authors argue that the criterion of "medical necessity" may no longer be, if indeed it ever was, adequate for determining which health services should be publicly funded. They do not believe that any single criterion can fulfill this role. Instead, they propose that policy makers focus on developing a better process for making choices among health care priorities. Clearly defined roles in this process must be established for payers, the public and providers.

Starting consumers off on the "path to purchase" by encouraging them to seek more information is a major goal of direct-to-consumer (DTC) advertising for prescription medications. But the authors found that a consumer's attitude toward DTC advertising can determine which of several paths he or she is likely to take. The attitudes of older adults are especially significant for pharmaceutical marketers because these consumers are heavy users of the drugs being advertised.

The spectra of active galaxies and their nuclei are rich in emission and absorption line features. A major aim of present research is the development of self-consistent hydrodynamic models for the production of the line-forming regions. We here review such modelling and stress the central role played by shock phenomena induced by winds and explosions on scales ranging from the circumstellar to the intergalactic.

6H‐SiC MESFET’s have been fabricated and tested at temperatures up to 673 K. Fabrication procedures have been briefly outlined and electrical characteristics of these devices presented with consideration for use in high temperature electronic circuits. The extrapolated threshold voltage (VTH), transconductance (gm), and small‐signal voltage gain (Av) were plotted vs. temperature, showing that the devices retained good electrical characteristics up to 523 K. Emission currents and charge transport across the Schottky barrier gate contact were examined in relation to the maximum operating temperature of the devices. Logarithmic plots of the gate‐to‐source current vs. applied voltage demonstrated the effect of gate leakage currents and also provided information about the current conduction mechanisms in the channel.

We propose that a significant fraction of the ultracompact HII regions found in massive star-forming clouds are the result of the interaction of the wind and ionizing radiation from a young massive star with the clumpy molecular cloud gas in its neighbourhood. Distributed mass loading in the flow allows the compact nebulae to be long-lived. In this paper, we discuss a particularly simple case, in which the flow in the HII region is everywhere supersonic. The line profiles predicted for this model are highly characteristic, for the case of uniform mass loading. We discuss briefly other observational diagnostics of these models., To appear in Monthly Notices of the Royal Astronomical Society. 5 pages LaTeX (uses mn.sty and epsf.sty macros) + 4 PS figures. Also available via http://axp2.ast.man.ac.uk:8000/Preprints.html

Molecular clouds are clumpy on length scales down to the limits of observational resolution. At least some ultracompact Hii regions (UCHiiR) may result from the interaction of a young early type star and this type of cloud. The clumps can act as reservoirs of ionized gas distributed within the Hii region. These models reproduce the relatively long lifetimes implied by the population statistics of UCHiiR. We present line profile and emission measure plots based on the simplest case where the flow remains supersonic through to a recombination front. The morphology agrees with the shell-like UCHiiR as classified by Churchwell. The predicted line profiles are broad and double peaked with a separation of about 50 km s−1 for the example given.

We present work investigating the stability of line-driven winds using a non-Sobolev approach. We find that the dense shell structures which characterise the growth of radiation-driven instabilities in one dimensional simulations break up into numerous bow-shaped clumps in two-dimensions.

Using ab initio potential curves and dipole transition moments, cross-section calculations were performed for the direct continuum photodissociation of H{sub 2} through the B{sup 1}{Sigma}{sup +}{sub u}

This paper presents a numerical study of a single-shocked turbulent mixing layer using high-order accurate implicit large-eddy simulations (ILES) for low- and high-amplitude (linear and non-linear) perturbations and for a reshocked turbulent layer. It investigates the differences in flow physics between these three cases, examining a recent proposition that single-shocked high-amplitude initial perturbations can be employed to model a reshocked turbulent layer. At early times, the shocked high-amplitude perturbation has high levels of mixing; however, at later times, it grows in an almost identical manner to the low-amplitude case. Despite exploration of several choices of scaling to map the reshocked results to the single-shocked study, a satisfactory agreement could not be reached and mixing parameters remain disparate. The conclusion is that a single-shock interaction with a high-amplitude perturbation is not a good representation of reshock of a turbulent mixing layer.

A dual energy x-ray absorptiometry technique has been developed for the measurement of bone mineral in preterm infants. Two films are taken of the infant's forearm using a standard mobile x-ray set on the ward at two x-ray energies. Included in the field of view is a double step wedge made of aluminum and Perspex. The images are digitized by viewing them on a light box with a TV camera. The bone mineral content in the forearm can then be mapped by the measurement of light intensity in matching pixels of the two films and comparison with the intensities in the step wedge. The bone mineral concentration in the radius, expressed as bone mineral per unit length (mg/mm), is calculated. The technique has been tested using phantoms of calcium hydroxylapatite set in a tissue equivalent material and in Perspex. It has been shown that the reproducibility of the technique is approximately 7% and that there is a systematic underestimate of bone mineral of about 17%. The technique has been shown to be linear up to a bone mineral concentration of 8 mg.mm-1. Longitudinal studies for 14 infants that show an initial 6-wk period of demineralization after birth with a subsequent mineralization phase are reported.

Immunotherapy with lymphokine-activated killer (LAK) cells and interleukin 2 is one of the newer treatment modalities for cancer. This raises important questions concerning synergism or suppressive effects of other existing treatment modalities on adoptive immunotherapy with LAK cells. A tumor model with H4IIe hepatoma cells grown on each flank of ACI rats was developed to evaluate the effect of external beam irradiation of tumors on the subsequent concentration of LAK cells in these tumors. Tumors on one side were irradiated at 6, 12, or 16 Gy prior to injection of [3H]thymidine-labeled LAK cells. The effect of irradiation was measured as the ratio of 3H recovered in the unirradiated tumor compared to that in the irradiated tumor in the same animal as a function of dose and time after irradiation. This ratio was significantly greater than 1.0 for a radiation dose of 12 Gy (2.35 +/- 0.51) measured 2 days after irradiation, indicating a reduction in LAK cell numbers in the irradiated tumor. This reduction in LAK cell number persists up to at least 4 days following radiation exposure. A similar experiment using 125I-labeled interleukin 2 showed equal distribution in the irradiated and unirradiated tumors. Our data demonstrates that the concentration of LAK cells is markedly reduced by prior radiation, in contradistinction to increased uptake of immunoglobulins in irradiated tumors, as shown by others. If a similar reduction is observed for longer duration after radiation exposure, it might suggest a clinically important interaction between prior radiation exposure and adoptive immunotherapy.

The recent introduction of a 24-hour emergency theatre for General Surgery provided an opportunity to audit its effect on emergency operating in a District General Hospital. Prior to its introduction much of the emergency operating was determined by theatre availability rather than clinical need. Half of the emergency operations were carried out between 10 pm and 8 am. This proportion was reduced to a third when a theatre was continually available. This had benefits for the patients in reducing their waiting time and also for the junior surgeons by increasing their sleep. A survey of the Region indicated that very few hospitals provided adequate emergency theatre facilities.

Large differences in uptake between tumors, even for the same size, frequently observed in clinical and experimental radioimmunotherapy (RAIT), make monitoring of uptake in individual tumors imperative in comparing protocols. 90Y, widely-used for RAIT, emits no gamma radiation and absorption of the beta particle in tissue makes its detection unsuitable for in vivo monitoring. We tested whether bremsstrahlung radiation, produced when betas are decelerated by nuclei, could be used to monitor tumor uptake.Subcutaneous human LS174T colon carcinoma tumors were grown in the upper thigh of nude mice and labeled antibody injected intracardially. With the tumor placed in the 2 cm-diameter aperture in a lead collimator, photons with energies from 100 to 200 keV transmitted through plastic, which absorbed the beta particles, were counted to maximize shielding from the rest of the body. The contribution of the normal tissues was subtracted by counting the non-tumor-bearing leg in the same position. Excretion was calculated from whole body activity determined by removing the collimator, placing the mouse in a syringe surrounded by tissue-equivalent material 10 cm from the detector, and counting photons between 200 and 740 keV to minimize the effect of tissue attenuation.For tumors larger than 0.14 gm, a good correlation was obtained between the in vivo bremsstrahlung measurements and the measurements on excised tumors in a calibrated well counter. Similar excretion rates observed in all the animals suggested that the whole body counting was accurate.Bremstrahlung detection appears feasible and reliable for monitoring both tumor and whole body activities.

The history of health care delivery in Canada has been marked by close collaboration between physicians and the pharmaceutical and health supply industries, this collaboration extending to research as well as to education. Since medicine is a self-governing profession physicians have a responsibility to ensure that their participation in such collaborative efforts is in keeping with their duties toward their patients and society. The following guidelines have been developed by the CMA to assist physicians in determining when a relationship with industry is appropriate. Although directed primarily to individual physicians, including residents and interns as well as medical students, the guidelines also govern the relationships between industry and medical associations. These guidelines focus on the pharmaceutical companies; however, the CMA considers that the same principles apply to the relationship between its members and manufacturers of medical devices, infant formulas and similar products, and health care products and service suppliers in general. These guidelines reflect a national consensus and are meant to serve as an educational resource for physicians throughout Canada.

A Large Eddy Simulation of flow in a compound open channel with one floodplain at a Reynolds number of approximately 42000 is reported. The results are in good agreement with experimental measurements and previous numerical calculations. The secondary circulation field, bed stress distribution, and lateral stress distribution are presented in detail.

This paper presents a numerical study of turbulent mixing due to the interaction of a shock wave with an inclined material interface. The interface between the two gases is modeled by geometrical random multimode perturbations represented by different surface perturbation power spectra with the same standard deviation. Simulations of the Richtmyer-Meshkov instability and associated turbulent mixing have been performed using high-resolution implicit large eddy simulations. Qualitative comparisons with experimental flow visualizations are presented. The key integral properties have been examined for different interface perturbations. It is shown that turbulent mixing is reduced when the initial perturbations are concentrated at short wavelengths. The form of the initial perturbation has strong effects on the development of small-scale flow structures, but this effect is diminished at late times.

The biodistribution of 111In-labeled stabilized fragments of monoclonal antiferritin was studied in nude mice bearing a human hepatoma tumor xenograft. Pharmacokinetics and tumor targeting of fragment Fab'-linker-Fab' fragment molecules (stabilized F(ab')2) were compared to unmodified F(ab')2 fragment molecules and immunoglobulin G (IgG). Significant differences were observed in tumor and normal organ uptake at 12, 24, 48 and 72 hr. Tumor retention of stabilized F(ab')2 fragments was approximately 2.5-fold higher than of unmodified F(ab')2 at 48 hr. Blood clearance for stabilized F(ab')2 was relatively faster than intact IgG, while unmodified F(ab')2 cleared more rapidly from the circulation. Kidney radioactivity of unmodified F(ab')2 was at least two times higher than kidney radioactivity of stabilized F(ab')2 at all time points. Stabilized F(ab')2 demonstrated 40% less liver uptake than intact IgG. In these studies with nude mice, substantial retention of stabilized F(ab')2 in tumor and significant reduction in liver and kidney uptake of these fragments indicated that they could also have a higher therapeutic ratio than IgG or unmodified F(ab')2 in human patients.

Thirty-three enteric isolates from Australian (Escherichia coli only) and United Kingdom (U.K.) (Salmonella sp., Citrobacter spp., and E. coli) piggeries were characterized with respect to their copper resistance. The copper resistance phenotypes of four new Australian E. coli isolates were comparable with that of the previously studied E. coli K-12 strain ED8739(pRJ1004), in that the resistance level in rich media was high (up to 18 mM CuSO4) and resistance was inducible. Copper resistance was transferable by conjugation from the new Australian isolates to E. coli K-12 recipients. DNA similarity between the new Australian isolates and the pco copper resistance determinant located on plasmid pRJ1004 was strong as measured by DNA-DNA hybridization; however, the copper resistance plasmids were nonidentical as indicated by the presence of restriction fragment length polymorphisms between the plasmids. DNA-DNA hybridization and polymerase chain reaction analysis demonstrated DNA homology between the pco determinant and DNA from the U.K.E. coli, Salmonella sp., and Citrobacter freundii isolates. However, the copper resistance level and inducibility were variable among the U.K. strains. Of the U.K. E. coli isolates, 1 demonstrated a high level of copper resistance, 4 exhibited intermediate resistance, and 16 showed a low level of copper resistance; all of these resistances were expressed constitutively. A single U.K. C. freundii isolate, had a high level of copper resistance, inducible by subtoxic levels of copper. Transconjugants from one E. coli and one C. freundii donor, with E. coli K-12 strain UB1637 as a recipient, showed copper resistance levels and inducibility of resistance which differed from that expressed from plasmid pRJ1004.(ABSTRACT TRUNCATED AT 250 WORDS)

Rapid uptake and slow transit of radioactivity from normal organs are detrimental to any clinical utilized radioimmunoconjugate because they lower the target-to-nontarget ratio and deliver undesirable radiation to normal organs. To mitigate this problem, two labile chemical linkages (EGS and DST) were introduced between a monoclonal antiferritin antibody (QCI) and a chelating agent (DTPA). The biodistribution of labile-linker immunoconjugates (EGS and DST) and stable linker immunoconjugates (DSS and ITCB) were compared. In a nude mouse model, all of the four immunoconjugates labeled with 111In targeted subcutaneously-implanted human tumor cells. Tumor-to-normal organ ratios were enhanced for the EGS linkage in comparison to the two stable linkages. Serial whole-body immunoscintigraphy confirmed the biodistribution study. The EGS and ITCB 90Y-labeled immunoconjugates had biodistributions similar to their respective 111In-labeled immunoconjugates. As the mouse model is not representative of the high uptake of monoclonal antibodies in the human liver, beagle dogs were used to further explore the retention of radiolabel in normal liver. The EGS-linked immunoconjugate significantly reduced the dog liver activity when compared to the ITCB immunoconjugate. The combination of the animal models (mouse and dog) appears to allow for a more compete and optimal preclinical analysis of chelated radiolabeled monoclonal antibodies for diagnosis or treatment and illustrates the potential clinical improvements possible with labile chemical linkages in radioimmunoconjugates.

Family planning (FP) and social marketing messages must utilize the rules concerning artfulness developed in the private sector for effective communication in the mass media around the world. They have to compete for the attention of television program viewers accustomed to receiving hundreds of 30-second messages. There are some rules essential to any effective communication program: 1) Command attention. In the US over 1350 different mass media messages vie for attention every single day. FP messages are sensitive, but dullness and passivity is not a requisite. 2) Clarify the message, and keep it simple and direct. Mixed messages equal less effective communication. 3) Communicate a benefit. Consumers do not only buy products, they buy expectations of benefits. 4) Consistency counts. The central message should remain consistent to allow the evaluation of its effectiveness, but execution should vary from time to time and medium to medium. 5) Cater to the heart and the head. Effective communication offers real emotional values. 6) Create trust. Words, graphics, sounds, and casting in the campaign should support 1 central key promise to a single prime prospect. 7) Call for action. Both commercial and social marketing campaigns can calculate results by quantifiable measurement of sales (of condoms) transactions (the number of IUD insertions), floor traffic (clinic visits), attitude shifts, and behavior change. The PRO-PATER Vasectomy Campaign of 1988 in Sao Paulo, Brazil successfully used the above rules for effective communication. During the 1st 2 months of the campaign, phone calls increased by over 300%, new clients by 97%, and actual vasectomies performed by 79%.