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Macular degeneration (MD) causes central vision loss, removing input to corresponding representations in the primary visual cortex. There is disagreement concerning whether the cortical regions deprived of input can remain responsive, and the source of reported cortical responses is still debated. To simulate MD in controls, normally sighted participants viewed a bright central disk to adapt the retina, creating a transient ‘retinal lesion’ during a functional MRI experiment. Participants viewed blocks of faces, scrambled faces and uniform grey stimuli, either passively or whilst performing a one-back task. To assess the impact of the simulated lesion, participants repeated the paradigm using a more conventional mean luminance simulated scotoma without adaptation. Our results suggest our attempt to create a more realistic simulation of a lesion did not impact on responses in the representation of the simulated lesion. While most participants showed no evidence of stimulus-driven activation within the lesion representation, a few individuals (22%) exhibited responses similar to a participant with juvenile MD who completed the same paradigm (without adaptation). Reliability analysis showed that responses in the representation of the lesion were generally consistent irrespective of whether positive or negative. We provide some evidence that peripheral visual stimulation can also produce responses in central representations in controls while performing a task. This suggests that the ‘signature of reorganization of visual processing’, is not found solely in patients with retinal lesions, consistent with the idea that activity may be driven by unmasked top–down feedback.

To determine rates and predictors of postpartum diabetes screening among Aboriginal and/or Torres Strait Islander and non-Indigenous women with gestational diabetes mellitus (GDM).PANDORA is a prospective longitudinal cohort of women recruited in pregnancy. Postpartum diabetes screening rates at 12 weeks (75-g oral glucose tolerance test (OGTT)) and 6, 12 and 18 months (OGTT, glycated haemoglobin [HbAPostpartum screening rates with an OGTT by 12 weeks and 6 months postpartum were lower among Aboriginal and/or Torres Strait Islander women than non-Indigenous women (18% vs. 30% at 12 weeks, and 23% vs. 37% at 6 months, p 0.001). Aboriginal and/or Torres Strait Islander women were more likely to have completed a 6-month HbAGiven very high rates of type 2 diabetes among Aboriginal and Torres Strait Islander women, early postpartum screening with the most feasible test should be prioritised to detect prediabetes and diabetes for intervention.

Few studies have assessed whether children exposed to in utero hyperglycaemia experience different growth trajectories compared to unexposed children.To assess association of type 2 diabetes (T2D) and gestational diabetes mellitus (GDM) with early childhood weight, length/height and body mass index (BMI) trajectories, and with timing and magnitude of peak BMI in infancy.PANDORA is a birth cohort recruited from an Australian hyperglycaemia in pregnancy register, and women with normoglycaemia recruited from the community. Offspring growth measures were obtained from health records over a median follow-up of 3.0 years (interquartile range 1.9-4.0). This analysis included children born to Aboriginal mothers with in utero normoglycaemia (n = 95), GDM (n = 228) or T2D (n = 131). Growth trajectories (weight, length/height and BMI) were estimated using linear mixed models with cubic spline functions of child age.After adjustment for maternal factors (age, BMI, parity, smoking, and socioeconomic measures) and child factors (age, gestational age at birth, and sex), children born to mothers with T2D or GDM had lower weight, length/height and BMI trajectories in infancy than children born to mothers with normoglycaemia, but similar weight and BMI by completion of follow-up. Children exposed to T2D had lower mean peak BMI 17.6 kg/mMaternal hyperglycaemia was associated with differences in early childhood growth trajectories after adjustment for maternal BMI. Exploration of associations between in utero hyperglycaemia exposure and growth trajectories into later childhood is required.

SUMMARY The effects of K, Ca, Mg and H ions on the kinetics of Cd uptake by the moss Rhytidiadelphus squarrosus (Hedw.) Warnst were investigated. The affinity of extracellular exchange sites for these ions decreased in the order Cd, H > Ca > Mg ≫ K and there were competitive interactions between ions. The affinity of the intracellular Cd transport site for these ions decreased in the order Ca > Cd > Mg ≫ K. Calcium was shown to be competitive and Mg a non-competitive inhibitor of intracellular Cd uptake. Intracellular Cd uptake, optimal at about pH 5.6, was highly sensitive to pH, which primarily affected the Vmax. Potassium, supplied at less than 1 mM, had no significant effect on Cd uptake. However, at concentrations greater than 1 mM, KNO3 caused both a stimulation in transport site activity and reduced affinity for Cd. Pretreatment with KNO3 removed potentially competing ions from the cell wall, altering the subsequent chemical equilibria established when moss shoots were incubated in Cd solutions. Reduced competition from ions removed by KNO3 pretreatment resulted in a higher affinity of both transport sites and extracellular exchange sites for Cd, Ca and Mg. The results demonstrate quantitatively the regulatory effects on intracellular metal uptake of the extracellular ionic environment provided by the cell wall.

Summary The responses of field-grown and cultured shoots of a moss, Rhytidiadelphus squarrosus (Hedw.) Warnst, to Cd were investigated. Respiration was not affected, but photosynthesis was progressively reduced with increasing Cd uptake. Field-grown shoots of two morphologically distinct populations differed in their photosynthetic responses to Cd. This could be related to different rates of Cd uptake by the two populations. During storage of Cd-treated shoots, movement of extracellular Cd to an intracellular location occurred, and this was reflected in altered photosynthetic rates. The maximum extracellular uptake capacity and affinity for Cd were identical for the two populations of field-grown shoots. Field-grown material from the two populations differed significantly in their intracellular Cd uptake characteristics, cation contents, gas exchange rates and dry weights per unit length. These differences were eliminated by laboratory culture. Cultured shoots had increased affinity for both intra- and extracellular cadmium uptake compared to field-grown shoots. The results indicate that the activity of Cd and other divalent cations at the plasmalemma may control the affinity for and accumulation of Cd by this moss. The results are discussed in terms of the design of experiments in studies of ion uptake and tolerance in bryophytes.

Summary Is the brain able to reorganise following loss of sensory input? New work on individuals with sight loss shows that, while brain areas normally allocated to vision respond to other sensory stimuli, those responses are unlikely to mean the brain has rewired.

Background: In Australia’s Northern Territory, 33% of babies are born to Indigenous mothers, who experience high rates of hyperglycemia in pregnancy. We aimed to determine the extent to which pregnancy outcomes for Indigenous Australian women are explained by relative frequencies of diabetes type [type 2 diabetes (T2DM) and gestational diabetes (GDM)]. Methods: This prospective birth cohort study examined participants recruited from a hyperglycemia in pregnancy register. Baseline data collected were antenatal and perinatal clinical information, cord blood and neonatal anthropometry. Of 1135 women (48%Indigenous), 900 had diabetes: 175 T2DM, 86 newly diagnosed diabetes in pregnancy(DIP) and 639 had GDM. A group of 235 women without hyperglycemia in pregnancywas also recruited. Results: Diabetes type differed for Indigenous and non-Indigenous women (T2DM, 36 vs5%; DIP, 15 vs 7%; GDM, 49 vs 88%, p < 0.001). Within each diabetes type, Indigenous women were younger and had higher smoking rates. Among women with GDM/DIP,Indigenous women demonstrated poorer birth outcomes than non-Indigenous women:large for gestational age, 19 vs 11%, p ¼ 0002; neonatal fat 11.3 vs 10.2%, p < 0.001. Inthe full cohort, on multivariate regression, T2DM and DIP were independently associated(and Indigenous ethnicity was not) with pregnancy outcomes Conclusions: Higher rates of T2DM among Indigenous women predominantly contribute to absolute poorer pregnancy outcomes among Indigenous women with hyperglycemia.As with Indigenous and minority populations globally, prevention or delay of type 2 diabetes in younger women is vital to improve pregnancy outcomes and possibly to improve the long-term health of their offspring. Refereed/Peer-reviewed

Remote control and automated systems affiliated with Tubular Running Operations have been in use for the past 15 years with varied levels of success. Unsuccessful implementations have not elicited solutions, nor have successful implementations translated into a thriving industry standard. Though the oil and gas industry has changed much over the past 15 years, some of the same implementation challenges still exist. Service providers tend to have a "scattershot" approach to automating everything, rather than a concerted focus on exploiting small successes to realize specific company goals. This factor may be due to differing attitudes throughout the organization, ranging from upper management to business development to engineers. This can lead to the inability to cultivate a culture of technical progression among operators commensurate with the technical progression of equipment. From the service provider's perspective, an unwillingness to learn new technical concepts among operators may yield a general indifference about their own relevance within an automated industry, while the end customer may remain skeptical of the need for automation and become dissatisfied with the overall cost and time needed to implement automated solutions. Historically, industry insiders tended to mistake automation's inability to yield operational efficiency immediately as a failure. Overlooked is the fact that even the most cleverly implemented automation realizes better operational efficiency over time, with constant improvements and further integration. Additionally, some clients fail to realize that control systems are inconsistent from rig to rig. The absence of standardization may stem from corporations assigning more value to the retention of trade secrets than to an industry-wide focus on standardization. The following paper will examine—from the Tubular Running Services (TRS) provider perspective—the challenges associated with developing and deploying remote control and automated equipment. It will also give pragmatic solutions towards the successful implementation of this technology and prove that automation is not solely a technical hurdle for engineering to overcome.

Purpose Over the last two decades, magnetic resonance imaging (MRI) has been widely used in neuroscience research to assess both structure and function in the brain in health and disease. With regard to vision research, prior to the advent of MRI, researchers relied on animal physiology and human post‐mortem work to assess the impact of eye disease on visual cortex and connecting structures. Using MRI, researchers can non‐invasively examine the effects of eye disease on the whole visual pathway, including the lateral geniculate nucleus, striate and extrastriate cortex. This review aims to summarise research using MRI to investigate structural, chemical and functional effects of eye diseases, including: macular degeneration, retinitis pigmentosa, glaucoma, albinism, and amblyopia. Recent Findings Structural MRI has demonstrated significant abnormalities within both grey and white matter densities across both visual and non‐visual areas. Functional MRI studies have also provided extensive evidence of functional changes throughout the whole of the visual pathway following visual loss, particularly in amblyopia. MR spectroscopy techniques have also revealed several abnormalities in metabolite concentrations in both glaucoma and age‐related macular degeneration. GABA‐edited MR spectroscopy on the other hand has identified possible evidence of plasticity within visual cortex. Summary Collectively, using MRI to investigate the effects on the visual pathway following disease and dysfunction has revealed a rich pattern of results allowing for better characterisation of disease. In the future MRI will likely play an important role in assessing the impact of eye disease on the visual pathway and how it progresses over time.

This review illustrates the MR appearances of commonly encountered problems that can present as a "locked knee", as well as several unusual causes. Internal derangement of menisci, particularly bucket handle tears, predominate. Loose bodies as a result of trauma/degeneration and lesions such as cysts of the cruciate ligaments and focal pigmented villonodular synovitis are also illustrated. While meniscal tears are the major cause of "locked knee" in clinical practice, interference with normal knee kinematics is non-specific with regard to the diagnosis. Emphasis is therefore given to less frequently seen abnormalities that lead to a mechanical block of knee extension.

This paper describes the mathematical results of an investigation into the design of a rotating mirror for use in a laser-scanning display. The main design parameter considered in this work was the scan linearity. Using geometrical optics, the requirements of linearity result in a system equation of the quadratic differntial type. The mirror's shape was determined from the system equation in two ways. First, by approximate analytical solutions and, secondly, by numerical integration using a Runge-Kutta method. The linearity predicted by the Runge-Kutta method was essentially perfect, which supports the validity of the system equation. The linearities predicted by the approximate analytical solutions were satisfactory over a wide range of screen distances and display sizes. It is concluded that the application of this system equation will allow greater flexibility in the design of planar laser-scanning display systems when rotating mirrors are employed. Experimental results reported here support this view.

Using a sequential elution procedure, the cellular location of Cl−, Na+, Mg2+, K+ and Ca2+ was determined in the lichen Ramalina canariensis from the southwest coast of Portugal. After a dry deposition period, a logarithmic decrease in the extracellular (surface and wall-bound) concentration of Cl−, Na+ and Mg2+ was observed with increasing distance from the coast. The importance of each cellular fraction as an indication of the airborne salts was identified using factorial analysis methods, as was the relationship between the extracellular and intracellular concentration of the saline elements. The factorial analysis showed that the most important elements for the biomonitoring of airborne salinity were Cl−, Na+ and Mg2+. However, for the cations, only the surface and wall-bound (for Na+) fractions seem to be related to sea-salt deposition on the lichens. The intracellular fractions of these elements are relatively independent of the surface and wall-bound concentrations, or reflect some non-linear processes induced by extreme extracellular concentrations. Although they may represent a significant proportion of the total element concentration, intracellular element concentrations are of little value in monitoring salt deposition, due to physiological control by the organism. The use of total analyses, without any fractional differentiation, can be a biased method for biomonitoring the accumulation of salt spray by lichens, because it includes the intracellular fraction, which may be independent of the deposition taking place. The use of the different cellular fractions provides a more informative indication of the deposition of atmospheric elements, while also giving information on any physiological alterations induced by the specific environmental chemical factors, including membrane damage.

Heavy metal concentrations in Hylocomium splendens collected around a metal smelter in Latvia showed very high concentrations of Zn (>200 μg/g), and elevated concentrations of Pb (38.3 μg/g) and Cu (18.3 μg/g). In an attempt to better evaluate the potential toxicity of the high Zn concentrations, a serial elution method was used to determine the concentrations of zinc in intercellular, extracellular exchangeable cell wall, intracellular, and particle fractions. The intercellular Zn concentrations represent the water soluble component of the total concentrations, and were low with no clear trends. Zn concentrations in the extra- and intracellular and particle fractions decreased exponentially from the pollutant source. Intracellular Zn concentrations in moss close to the emission source are within the range considered to be potentially toxic, from other single element exposure studies. The proportion of Zn in the relatively insoluble particle fraction, which is least associated with environmental risk, was greater closer to the pollution source, reaching > 30% in the oldest Hylocomium splendens segments.

Using Infrared Thermography, three-way statistical correlation between forehead temperatures, frontal EEG and self-reports of core affect was applied in an experimental study to establish the underlying causal relationships between cognitive activity and supraorbital blood flow. Sub-groups were identified within the sample using the differentia of tonic forehead temperature asymmetry. Comparison between these groups showed that the so-called Right Dominant temperature sample exhibited statistically significant correlations between asymmetry in frontal alpha, forehead temperature and self-reported arousal throughout the experimental interactions. Individuals exhibiting this trait demonstrated greater reactivity to variation in the cognitive challenge of the tasks, presenting more readily measurable and distinctive patterns of asymmetric frontal cortical activity and temperature change. Detailed analysis showed significant patterns of correlation between hemispherical changes in specific beta frequencies, forehead temperature and self reported arousal and task engagement, indicating that forehead temperature dynamics reflected the underlying variation in cognitive demand evoked by the experimental stimuli.

To obtainHylocomium splendens(Hedw.) BSG. that varied in metal (K, Mg, Ca and Zn) content, moss samples were collected from six sites around a zinc contaminated area of Latvia; metal contents were artificially lowered by branch excision. The first fully expanded annual segment (mature segments), together with the unexpanded segment (juvenile segment) were grown in the laboratory with watering from below. The contents of K, Mg, Ca and Zn in new growth were correlated with initial contents in the juvenile+mature segments. However, the concentrations of these metals in the new growth were generally not correlated with those in the pre-experimental segments. The excision of branches from the mature segment favoured subsequent branch development in the young juvenile segment over further growth of the already expanded mature segment, but less new growth was observed when branches were excised.

A novel, non-destructive method for measuring moss gametophyte growth rates is presented. Standard 2-cm moss gametophores are supported vertically on Velcro strips held within a clear perspex box, with their bases resting in liquid. Shoots sampled from the field were either continuously exposed to test solutions via their cut bases, or by preliminary pulse-immersion. Growth was assessed by linear extension, or final dry mass, and showed different patterns and sensitivities to heavy metals using the two exposure methods. A biologically appropriate assessment of toxicity was established, using tissue concentrations comparable to material from polluted field sites, by considering the cellular location of heavy metals in shoots. A linear relationship was established between apical growth and intracellular Zn concentration recovered in the newly produced gametophyte tissue, irrespective of the method of exposure or Zn concentration in the remaining or original shoot portion. The limitations and ambiguity associated with many heavy-metal monitoring and toxicity studies are addressed, and the advantages and further applications offered by this growth system are discussed.

We have performed a new evaluation of the hadronic contribution to $a_{\mu}=(g-2)/2$ of the muon with explicit correlations of systematic errors among the experimental data on $\sigma( e^+e^- \to hadrons )$. Our result for the lowest order hadronic vacuum polarization contribution is $ a_{\mu}^{had} = 702.6(7.8)(14.0) \times 10^{-10}$ where the the first error is statistical and the second is systematic. The total systematic error contributions from below and above $\sqrt{s} = 1.4$ GeV are $(13.1) \times 10^{-10}$ and $(5.1) \times 10^{-10}$ respectively, and are hence dominated by the low energy region. Therefore, new measurements on $\sigma( e^+e^- \to hadrons )$ below 1.4 GeV can significantly reduce the total error on $a_{\mu}^{had}$. In particular, the effect on the total errors of new hypothetical data with 3 \% statistical and 0.5 - 1.0 \% systematic errors is presented., Comment: LaTeX with REVTeX style and options: multicol,aps,psfig. 18 pages, postscript figures included after text. Accepted in Phys. Rev. D (~ Sept 1996)

The intracellular and extracellular contents of K, Mg and Ca, dry weight and CO2 exchange rates in successive 2-cm segments of Rhytidiadelphus squarrosus (Hedw.) Warnst, were recorded before and after storage of moss shoots collected from the field. Moss shoots sustained apical growth in the absence of aerial or substratum nutrient inputs and acropetal transfer of cations occurred at the expense of basal segments. Intact shoots of 12–17 cm initial length showed increased or decreased cation contents, respectively, in the uppermost segments according to whether infrequent or frequent watering regimes were employed. Excised shoots of 4 or 8 cm retained cations despite a frequent watering regime. Acropetal transfer of cations during growth of excised shoots was in proportion to the available cation pool. There was no evidence that nutrient limitation in the growing apex affected growth or metabolism. Pre-treatments which modified the initial Ca, Mg and K status of moss shoots did not influence the pa...

SUMMARY Cadmium uptake by photosynthetically Cd-tolerant and intolerant populations of the moss Rhytidiadelphus squarrosus (Hedw.) Warnst and the lichen Peltigera membranacea (Ach.) Nyl. was investigated. Intolerant plants showed increased intra cellular Cd uptake compared to Cd-tolerant material. Kinetic analysis indicated that reduced intracellular Cd uptake by Cd-tolerant plant material was reflected in an increased Km or decreased Vmax for Cd. Pretreatment with KNO3 modified the extra cellular ion content of plant material, significantly reduced the apparent Km and could increase or decrease the Vmax for intracellular Cd uptake. Changes in kinetic constants caused by K pretreatment could be related to altered chemical equilibria when plant material was incubated in Cd solutions. Selective exclusion of Cd from intracellular locations was excluded as a tolerance mechanism in R. squarrosus and P. membranacea. Contrasting kinetic constants for intracellular Cd uptake in intolerant and Cd-tolerant plant material were due to the prevailing extra cellular ion content when collected from the field. In R. squarrosus, K pretreatment resulted in increased uptake capacities and cell-wall binding affinities for Cd in field-grown moss apices. Laboratory-grown apices, following K pretreatment, displayed increased uptake capacities but reduced affinities for Cd. Increased extra cellular Cd uptake in K-pretreated moss apices was interpreted as additional weak electrostatic binding. Kinetic analysis indicated that electrostatic binding by extra cellular sites was less influential than the available supply of wall-bounds ions on intracellular Cd uptake by moss apices.

A number of possible displacing agents have been tested for their ability to release extracellular bound lead from Cladonia portentosa. Metal cations (Ni and Cu), thiol–rich reagents (glutathione, ammonium pyrrolidinedithiocarbamate) and some chelating agents (EGTA, EDTA at pH 9·5 or pH 2·7) were ineffective or caused membrane damage. Disodium EDTA at pH 4·5 was found to be an effective displacing agent, although the Na caused some release of intracellular K without membrane damage. This displacement procedure showed that no Pb suppliedin the laboratory entered the protoplast in 2 h. The effect of Ca, Cu, Pb, and Sr on membrane integrity was investigated.

Two populations of Rhytidiadelphus squarrosus, from metal-contaminated and uncontaminated habitats, differed in their intra- and extracellular Cd contents but had similar cellular levels of Cu. Moss shoots were supplied with a pulse of toxic metal by incubating in Cu or Cd nitrate solutions and effects on respiration, photosynthesis and intracellular K loss were monitored with time after initial exposure. Increasing intracellular Cu levels correlated most closely with a concurrent decline in intracellular K. Photosynthesis also declined in proportion to intracellular Cu; significant Cu-induced stimulation of respiration was observed. The most significant effect of Cd treatment was a decline in photosynthesis in proportion to the intracellular concentration of Cd. Apical segments from both populations showed similar sensitivity to Cu, whereas the metal-contaminated population showed increased resistance to Cd. Sensitivity to Cd increased in the more basal portions of moss gametophores, indicating that apparent resistance of Cd might reflect shoot vitality and age effects. After laboratory growth to eliminate differences in the physiological status of apical segments, it was confirmed that the metal-contaminated population of the moss was photosynthetically more tolerant to Cd at intracellular Cd concentrations found to cause considerable photosynthetic inhibition in the uncontaminated population. The metal-contaminated population of the moss that was tolerant to Cd was not co-tolerant to Cu.

A number of physiological processes relevant to the role of lichens in mineral cycling are discussed. Consideration is given to the cellular location of positively-charged cations, showing (a) the benefits of quantifying intracellular elements for the interpretation of toxic metal stress, and (b) how distribution patterns of physiologically essential elements may be altered by desiccation and rehydration under field and laboratory conditions. The quantitative significance of these dynamic processes associated with metal uptake and loss requires verification under field conditions. A modified sequential elution procedure is proposed that enables quantification of insoluble paniculate mineral matter (acquired by wet and dry deposition) in addition to soluble elements in intercellular, extracellular-exchangeable and intracellular sites.

The present study compares the effect of Cd, Cu, Ni, Pb and Zn, applied as single salt solutions between 10 μm and 0.1 M, on physiological processes in Rhytidiadelphus squarrosus and relates these responses to the quantity and location of metals taken up by the moss. A more reproducible relationship between metal uptake and physiological response is established.

Direct information on nutrient cycling through bryophytes is limited and often incomplete. Evidence bearing on the sources and pathways by which nutrient elements are acquired (e.g. aerial deposition, throughfall and substratum) and lost (e.g. leaching and decomposition) is critically discussed. The need to distinguish between the extracellular and intracellular location of elements is emphasized. The involvement of microorganisms and the problems of accurately measuring decomposition are considered. A summary is given of recent laboratory work on the internal redistribution of elements in Rhytidiadelphus squarrosus and of field experiments involving fertilizer addition to Pseudoscleropodium purum; their significance is assessed.

This paper will describe the analysis and experimental methods used to understand and reduce turbine end High Cycle Fatigue (HCF) of a fixed geometry turbocharger. The turbine housing flow field is investigated using a computational fluid dynamics (CFD) code and subsequently compared to detailed pressure measurements around the volute exit. This study resulted in a new housing design which showed an improvement to the measured strain value. The paper then describes how an analysis technique was developed to integrate the aerodynamic and structural analysis of the wheel in order to predict the blade strain distribution at the mode 1 frequency. These predictions are successfully compared against the test data at two speeds relating to the different orders of this mode for both the old and new turbine housing stages.

The authors have constructed and tested seven projective scintillating fiber-copper absorber hadron calorimeter towers for high-energy hadron collider detectors. Each tower contained 2.25% by volume scintillating fibers, embedded between copper laminations, 10.6 lambda deep. A hadron energy resolution of sigma /E=91%/ square root E was obtained. Pions exhibited uniform response when scanned across boundaries between modules and through a range of incident angles with respect to the fibers. The e/ pi ratio is 1.08+or-0.02 for energies between 10 and 20 GeV, with a response of approximately 60 p.e./GeV. The muon Landau distributions well-resolved from pedestals were observed. >

The technology to construct cast lead-eutectic scintillating fiber calorimeters for measuring the energy of hadron and electromagnetic showers is discussed. The lead eutectic injection process, mold construction and release equipment, and fiber preform are described, along with beam test results on prototypes. Novel extensions of the technique include liquid fiber forward calorimeters, and shot-loading of the molten eutectic to achieve variable absorption properties. This lead eutectic and eutectic/shot slurry casting technique for solid and liquid fiber calorimetry has significant potential advantages in the ease of fabrication compared with laminated fiber insertion techniques while preserving an electromagnetic resolution similar to that obtained with laminated fiber calorimeters. The addition of micro-shot to the molten eutectic enables fiber calorimeters with variable properties, such as an interaction length approximately 30% smaller than lead calorimeters (tungsten loading), or modified neutron sensitivities. The combination of short radiation length/Moliere radius ( approximately 1/2 of BaF/sub 2/, for example), low cost, and energy resolution is unique. >

Hyperbaric oxygen (HBO) therapy is recognized as an adjunctive treatment for osteoradionecrosis (ORN). It may also be used prophylactically in patients who require dental extractions and are at high risk for developing ORN. This article reviews the treatment outcomes of patients treated with HBO therapy at the Toronto General Hospital from 1985 to 1997.A total of 297 charts of patients treated with HBO were reviewed. Criteria assessed included age of patient, gender, original diagnosis, radiation dose, time between radiation treatment and onset of ORN, presence or absence of fracture, orocutaneous fistula, pain, history of a precipitating event triggering ORN, medical status, HBO therapy (total oxygen time, number of dives), method of treatment of ORN and follow-up period. Minimum patient follow-up time for inclusion in the study was 6 months.Adequate information to meet the inclusion criteria was obtained for 75 patients. Group A (51 patients) had been treated for overt ORN with HBO alone, HBO with sequestrectomy, or HBO with sequestrectomy and reconstruction. Group B (24 patients at risk for developing ORN) had been treated with HBO prophylactically for dental extractions. In group A, only 3 patients (5.9%) failed to show improvement. In group B, only one patient (4.2%) had complications during healing.Encouraging results were achieved when HBO was used in the 2 groups described above. This paper supports existing literature on the potential benefit of HBO as a prophylactic agent and adjunctive treatment of ORN.

A variety of free flaps have been successfully used for mandible reconstruction. This study compared the short- and long-term results of using the free iliac crest and fibula flaps.We conducted a retrospective analysis of 117 patients who underwent mandibular reconstruction, 59 patients with iliac crest and 58 with free fibula. Accurate long-term functional assessment was possible in 31 cases in the iliac crest group and in 48 patients with fibular reconstruction. Anterior or combined anterolateral defects formed 72% and 64% in the iliac crest and fibula groups, respectively. The remainder were pure lateral defects. In both series, a skin paddle was included to provide either lining, skin cover, or both in 77% of the cases, whereas in 23% bone only was used.Complications included two perioperative deaths and three flap losses in the iliac crest group and five flap losses in the fibula group. Long-term functional and cosmetic assessment showed no statistically significant differences in oral continence (p0.9), speech (p = 0.57), and contour results (p = 0.80) between the two groups. However, oral deglutition was statistically significantly better in the fibula free flap group (p = 0.009).Although the fibula free flap is the flap of choice, the iliac crest is an excellent and reliable complementary flap for mandibular reconstruction.

The supraomohyoid neck dissection (SOHND) is often performed in patients with cancer of the oral cavity, where there is no clinical or radiologic evidence of regional metastases. When on pathologic examination positive neck nodes are found, however, some consider it a curative operation, whereas others regard it as a staging procedure only.We retrospectively reviewed 43 patients with cancer of the oral cavity who had a SOHND during the period from 1991 to 1994. All patients were staged as having N0 disease and had a total of 48 SOHNDs (38 unilateral, 5 bilateral). The follow-up period was at least 2 years.Seven of 48 N0-staged necks showed occult metastasis (15%). Two of these patients received postoperative radiotherapy. One of 7 (14%) patients with pathologic node-positive disease on the SOHND side developed recurrent ipsilateral neck disease during the follow-up period, whereas 4 (10%) recurrences developed in 41 necks that were pathologically staged as N0. Survival was 88% for patients with pathologically N0 necks versus 86% for patients with pathologically N+; disease.Supraomohyoid neck dissection is an effective staging procedure; however, in this group of patients, neck recurrence and patient survival after SOHND appear not to be related to pathology N stage. Also, SOHND with or without adjuvant radiotherapy appears to control the neck in the majority of patients, attesting to therapeutic efficacy. A prospective study is needed, however, to see if a "wait and see" policy does not achieve similar long-term outcome.

Medical education generally is so complex today, compared to just 50 years ago, that we unfortunately brush over the education of common conditions and their management in favour of more esoteric and complicated disease. Otitis media (OM) is no exception, and now more than ever, we must strive to find innovative ways to convey the mandatory information to medical students and practising physicians as we approach the millennium. This article addresses the problems of teaching the essential information and management skills needed by medical practitioners by reviewing what has gone on in the past, updating the present situation, and suggesting new strategies for the future.

Currently, there is no uniformly accepted metastatic work-up of the patient with head and neck cancer. Various protocols range from selected laboratory investigations and a chest x-ray to more extensive radiologic screening surveys. Although it is desirable to have as much information available as possible prior to making a decision of operability, one is confined by the cost of extensive investigations. This study was conducted to evaluate the benefit of routine bone scanning preoperatively in these patients.A retrospective study looked at a consecutive 172 patients undergoing a bone scan with respect to indication, diagnosis, scan result, and tumour stage.Only three patients had a change in their management based on the bone scan results.The incidence of bone metastases in the majority of patients with squamous cell carcinoma of the head and neck do not warrant routine bone scans for investigation of metastases.

The purpose of this study was to determine the rate of post-laryngectomy pharyngocutaneous fistulae and its association with age, gender, preoperative radiation, TNM staging, patients comorbidity factors, choice of ablation, choice of reconstruction, modality of postoperative feeding, and whether or not a primary tracheoesophageal puncture was performed.Retrospective clinical study.The Toronto Hospital/Princess Margaret Hospital, University of Toronto, Toronto, Ontario.One hundred and twenty-five consecutive laryngectomy procedures performed between July 1, 1992, and October 1, 1996, were reviewed.There was an overall fistula rate of 22%. No association found was between fistula rates and age, gender, patient comorbidity factors, TNM stage, choice of ablation, choice of reconstruction, modality of postoperative feeding, or whether a primary tracheoesophageal puncture was performed or not.At this tertiary care head and neck oncology centre, pharyngocutaneous fistulae remain an unpredictable and serious complication with an estimated economic cost of Cdn $400,000 per year.

The incidence of internal jugular vein thrombosis (IJVT) following a modified neck dissection remains uncertain. The effect of, or consequences following, IJVT upon pedicled and free flap head and neck reconstructions remains unexplored.Twenty-nine preserved internal jugular veins in 24 patients undergoing modified neck dissection were available for prospective study. All patients required a pedicled or free flap reconstruction and received a modified, unilateral or bilateral cervical lymphadenectomy. The patency of all jugular veins was determined preoperatively and postoperatively using a combination of computed tomography (CT) scanning, high-resolution ultrasound, and color-flow Doppler (CFD).The IJVT rate was 14%. The presence of a pedicled myocutaneous flap and left-sided jugular dissections may represent risks to the postoperative patency of the internal jugular vein. Preoperative radiotherapy did not appear to impact negatively upon the thrombosis rate.Thrombosis of the internal jugular vein may result in significant morbidity for the postoperative oncologic patient. An internal jugular-dependent-free-tissue transfer may risk venous compromise of the flap, whereas the use of a pedicled flap may place the jugular at increased risk for thrombosis. Strategies for deep venous system microvascular recipient recruitment in the head and neck are discussed. Wherever possible, we employ two deep venous systems, the internal jugular, and subclavian (via the external jugular) for flap drainage.

The general purpose detector CMD-2 at the VEPP-2M electron-positron collider at Novosibirsk has collected about 11 pb−1 of integrated luminosity in the center-of-mass energy range from 0.36 up to 1.38 GeV. Data in the ρ-meson energy range from 0.61 to 0.96 GeV have been analysed and preliminary results on the e+e−→π+π− cross-section in this energy range are presented.