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Existing published models for orogenic gold deposits (OGDs) do not adequately describe or explain most deposits of Phanerozoic age, and there are numerous reasons why Phanerozoic OGDs might differ significantly from older deposits. We subdivide Phanerozoic OGDs into four main subtypes, based on a number of descriptive criteria, including tectonic setting, lithological siting, and characteristics of the mineralization in each subtype. The four subtypes are: (1) crustal-scale fault-associated (CSF) subtype, (2) sediment-hosted orogenic gold (SHOG) subtype, (3) forearc (FA) subtype, and (4) syn- and late tectonic dispersed (SLTD) subtype. Lead isotopic studies suggest that Pb and other metals in all but the FA subtype were likely derived from relatively small source reservoirs in the middle or upper crust. OGDs formed in large, lithologically and structurally homogeneous regions will tend to be of the same subtype; however, in geologically complex orogenic belts it is common to find two or more subtypes that formed at approximately the same time. Based on the synthesis of global OGDs of Phanerozoic age, districts containing CSF or SHOG subtype deposits appear to have the best potential for hosting multiple large deposits. FA subtype deposits form in a relatively uncommon tectonic setting (accretionary forearc, possibly overlying a subducting spreading ridge) and are likely to be rare. SLTD subtype OGDs are the most common, but most are small and uneconomic, although they commonly generate substantial alluvial gold deposits.

Compositional analysis is an important component of an integrated comparative approach to assessing the food and feed safety of new crops developed using biotechnology. As part of the safety assessment of cassava brown streak disease resistant 4046 cassava, a comprehensive assessment of proximates, minerals, amino acids, fatty acids, vitamins, anti-nutrients, and secondary metabolites was performed on leaf and storage root samples of 4046 cassava and its non-transgenic parental control, TME 204, collected from confined field trials in Kenya and Uganda over two successive cropping cycles. Among the 100 compositional components that were assessed in samples of 4046 and control TME 204 cassava roots (47 components) and leaves (53 components), there were no nutritionally relevant differences noted. Although there were statistically significant differences between the transgenic and control samples for some parameters, in most cases the magnitudes of these differences were small (

Noise in hospital wards has the potential to slow down the recovery of patients. A comprehensive and systematic analysis of noise levels and noise sources has been carried out in two intensive care units and one high dependency unit in two Edinburgh hospitals (UK). Noise levels LAeq,1min and LAFmax were measured at 1 minute intervals for 24 hour periods, and noise sources responsible for LAFmax were identified. High noise levels were found in the three wards, the lowest LAeq,1min being measured in the modern ward tested, where an acoustic ceiling was present. A substantial number of noise sources have been observed and analysed statistically, many of which had never been identified by previous research. It was found that 34% of these are totally avoidable and 28% are partially avoidable. Noise control solutions are presented, with practical solutions affecting 48% of the noise sources, and staff education affecting 14% of the sources. Practical application: The analysis and classification of noise sources obtained has lead to the identification and presentation of practical noise control solutions, some of which can be implemented at the design stage. This is of direct relevance to building services engineers who play a role in the design of hospital wards, and can therefore use this information. It can also be noted that average and maximum noise levels measured in this study could form the basis for the development of noise guidelines in intensive care units and high dependency units, as current limits do not appear to be appropriate for such spaces.

Ombuin (7,4'-dimethyl quercetin) (10 μg ml -1 , for 12 wk), glycyrrhizin/ quercetin (80 μg ml -1 and 10 μg ml -1 respectively, for 18 wk), ribavirin (10 μg ml -1 , for 12 wk) and quercetin/ribavirin (10 μg ml -1 each, for 9-12 wk) reduced the titre of apple stem grooving virus (ASGV) when applied in vitro to infected tissue cultures of Nicotiana occidentalis obliqua Wheeler, and/or Malus domestica. ASGV was not detectable in both plant species after the quercitin/ ribavirin treatment when tested by ISEM, herbaceous host indexing, RT-PCR, and immunocapture RT-PCR. A sensitive immunocapture RT-PCR procedure for the detection of ASGV was developed for the screening of treated samples to assess antiviral activity.

Surgical repair of the acutely fractured orbit strives to restore appearance, preserve ocular and orbital function, and avoid enophthalmos or hypoglobus. Repair is achieved with autologous bone graft, synthetic substitutes, or both. The purpose of this article is to present an alternative procedure--use of implants, cut from a titanium mesh screen, without bone graft.A total of 51 orbital floor fractures in 43 patients were repaired with titanium mesh screen implants. In three patients with bilateral orbital floor fractures repaired with titanium mesh, intraoperative symmetry was improved with bone graft added to the mesh on one side.Follow-up was available for 42 orbits in 35 patients and averaged 9 months. The transconjunctival approach with lateral canthotomy yielded better results than the subciliary approach, which often caused transient scleral show or ectropion. One patient underwent surgery for ectropion following a subciliary approach, and one patient developed a 4-mm enophthalmos. Routine bone grafting is unnecessary, even in large floor defects. Titanium mesh implants are a simple and reliable option for orbital floor repair.

Patients with clinical brain death following head injury are important potential cadaveric organ donors. We analyzed our series of cranial gunshot wounds with particular attention to the frequency and patterns of organ donation after fatal injuries. Sixty-six patients with gunshot wounds to the head, including 59 with intracranial involvement (43 male, average age 26 years) were seen during a 4-year period. Injuries were limited to the head in 50 of 59 patients. Overall mortality was 66 per cent. Predictors of mortality included Glasgow Coma Scale (GCS) of six or less (93%), self-inflicted gunshot wounds (75%), and computed tomography (CT) findings of bihemispheric injury (87%) or ventricular injury (82%). Of the 39 patients who died, 28 met standard criteria for brain death, and nine of these went on to organ procurement. Thirteen families refused donation, and six patients were not harvested for reasons including old age, pregnancy, suspicion of AIDS, coroner refusal, and failure to pursue consent. Principles essential to maximal organ retrieval include: 1) Recognition that patients suffering cerebral gunshot wounds represent potential organ donors and that certain factors are predictive of mortality; 2) Critical care/trauma team approach with standardized management and timely declaration of brain death; 3) Early search for family members and prompt notification of organ procurement agencies; 4) Sensitivity to cultural issues influencing donation; and 5) Programs to increase public awareness of organ donation.

The accuracy and reliability of an invasive intra-arterial oxygen sensor catheter was evaluated in 20 critically ill surgical intensive care unit (SICU) patients. All patients required continuous arterial blood pressure monitoring, at least 72 hours of ventilator support, and intermittent arterial blood gas sampling for clinical management. The intra-arterial sensor provided continuous PO2 (PsO2) values on a bedside electronic monitor. PsO2 values were sampled every 60 seconds and automatically stored on a bedside personal computer. Arterial blood gas (ABG) PaO2 values were collected and matched by collection time with corresponding PsO2 values. During 1,238 hours of continuous intra-arterial monitoring, 74,280 PsO2 values and 246 ABG PaO2 values were collected. Of the 246 PaO2 results, 175 (71.3%) had a matching PsO2. Regression of matched PsO2 and PaO2 values yielded a correlation coefficient of 0.58 and standard error of the estimate (SEE) of 33.1 (P0.0005). Even though matched PsO2 and PaO2 measurements demonstrated a linear relationship, only 34 per cent of the variation in PsO2 could be attributed to changes in PaO2. Technical sensor or instrument problems affected PsO2 monitoring in 17 of 20 patients and 28 of the 33 sensors tested. The authors conclude that continuous intra-arterial monitoring of PsO2 is a novel idea, but technical issues limit its use in acutely ill, conscious SICU patients.

A national survey was conducted in Canada during 1994 and 1995 for four viral pathogens of quarantine significance in grapevine. A total of 11,417 samples, collected from 637 field sites, was tested for the presence of arabis mosaic virus (ArMV), grapevine fanleaf virus (GFLV), and two viruses commonly associated with grapevine leafroll disease, grapevine leafroll associated virus types I (GLRaV-I) and III (GLRaV-III). Nationally, the incidence of nepovirus-infected samples was low, 0.53 and 0.25% for ArMV and GFLV, respectively, and higher for the two leafroll associated viruses, 1.67% for GLRaV-I and 10.8% for GLRaV-III. Nepoviruses were found only in samples of varieties of Vitis vinifera origin or hybrid crosses, whereas GLRaV-I and GLRaV-III were found in samples of all variety types. Among the varieties tested, GLRaV-III was found primarily in samples of hybrid (14.8%) or other (including the Labrusca varieties Concord, Niagara, and Elvira) (13.5%) origin, whereas GLRaV-I was found predominantly in samples of V. vinifera (4.05%) origin. The widespread occurrence of these viruses in Canada has resulted in a reevaluation of their current quarantine status.

Prunus virus isolates (PVIs) were found that cross-reacted with plum pox virus (PPV) polyclonal antisera in immunosorbent electron microscopy, immunogold labeling, and Western blot analysis. The positive reactions in Western blot analysis were not affected when bovine serum albumin, fetal calf serum, glycerol, D-glucose, or skimmed (defatted) milk were used as blocking agents. Monoclonal antibodies to PPV reacted with the PVIs in Western blot analysis. The PVIs and some PPV isolates also cross-reacted in immunosorbent electron microscopy and Western blot analysis with apple stem pitting virus polyclonal antisera. The RNAs associated with the PVIs were analyzed to evaluate their homology with PPV RNA. The double-stranded RNA (dsRNA) profile of the PVIs showed that there were 3 to 5 dsRNA species ranging in size from 2.7 to 7.4 x 10 6 Da. Oligonucleotide sequences corresponding to the 3' noncoding region, the 5' noncoding region, and the 3' terminus of the coat protein coding sequence of a non-aphid-transmissible strain of PPV (PPV-NAT) were used as probes in hybridization studies and as primers in reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. The PVIs did not react. RT-PCR analysis using PPV-specific primers from the conserved 5' terminus of the coat protein coding sequence of PPV gave negative results with all PVIs. These analyses of the viral genome indicate that the PVIs are not isolates of PPV. Further studies to determine if the PVIs were members of the potyvirus group were negative. No evidence of associated cytoplasmic cylindrical inclusions or reaction with a potyvirus-specific monoclonal antibody was observed. The PVI particles ranged in size from 740 to 791 nm in length, and 10.4 to 14.4 nm in width. The coat protein subunit molecular mass ranged from 48 to 56 kDa, and can be distinguished from PPV by Western blot analysis. The implications of the serological cross-reactions are discussed.

The reactivity of six monoclonal antibodies with native southern bean mosaic virus particles, swollen virus, swollen virus contracted by divalent cations or by pH adjustment to 5.0, and virus coat protein at pH 7.5 and 5.0 were assessed by antigen inhibition enzyme-linked immunosorbent assays. Clones B4, B7, and B11 did not react with native virus but were inhibited by low levels of all nonnative virus antigens. B6 had a high reactivity only with the native virus. B5 and B10 reacted equally with native virus and swollen virus contracted by Ca2+ or by pH adjustment, but reacted only weakly with swollen virus or swollen virus contracted by Mg2+. B5 reacted with viral protein at pH 5.0 and weakly with coat protein at pH 7.5, whereas B10 did not react with protein at pH 7.5 and had only limited reactivity with viral protein at pH 5.0. The reactivity of B5 and B10 with swollen virus increased as the pH was gradually decreased between 7.3 and 6.5. Similarly, their reactivity with swollen-contracted virus decreased as the pH was increased within the same range. Reactivity versus pH plots of these two transition forms showed hysteresis with B10 but did not with B5.

Celestin pulsion and traction tubes (Celestin, 1959; 1978) are frequently used in the treatment of both malignant and benign strictures of the oesophagus. Occasional late complications of intubation include dislodgement of the tube, which may be passed intact from the anus, and also fragmentation of the tube (Mackenzie et al., 1976; Rao, 1978; Brown and Hughes, 1979; MacGowan, 1980) which may have serious consequences. Radiological monitoring of the position and integrity of these tubes is made possible by the presence of a single radiopaque marker line in some models, while others are radiopaque throughout.

Analyses of the carbohydrates in the leaf and stem of perennial rye-grass were carried out during uninterrupted growth from May to November. Although there were individual variations in the amounts of glucose, fructose and sucrose present, no major seasonal trends in these sugars were evident. The plant accumulated in the stem a reserve of fructosan which reached a maximum of 21% of the dry matter before it diminished in the autumn. There was a gradual increase in the percentages of cell-wall polysaccharides. The relation between fructosan accumulation and synthesis of cell-wall material during the growth of the plant is discussed. The autumn aftermath growth was analysed and its composition compared with that of the first growth.

The seasonal variations of the carbohydrates in the leaf and stem of lucerne have been studied during two successive years' growth. During growth from seed in the first year, when the crop did not flower, there was a continuous accumulation of sucrose in the plant. In the second year, flower and seed formation influenced the soluble sugar content, which was highest when the flowers were in bloom. This substantiates field observations by other workers that the best hay and silage are obtained from material cut at this stage. In both years there was a continuous increase in the amount of cell wall polysaccharides.

Incidental learning data was obtained by testing if Ss recognized words previously used in a memory scanning task. In the memory scanning task, Ss had compared probe words to memory sets consisting of one to four words, responding positively if the probes matched one of the memory set words or otherwise responding negatively. The incidental learning scores differentiated between certain memory set conditions: (1) Words from memory sets of one had higher scores than those from larger memory sets. (2) Positive probe words were better recognized than all other words. (3) There were no differences between memory sets larger than one item.

Subacute sclerosing panencephalitis can no longer be regarded as a rare disease in all parts of southern Africa. Information derived from a third postal survey added to that from our own experience in Cape Town has brought to light 116 cases; 61 of the patients came from the Cape Province, 40 from the Transvaal and the remaining 15 from the other regions. This unequal distribution and the high prevalence in the Coloured community are important factors in any attempt to understand the epidemiology and the pathogenesis of this serious complication of measles.

A first attempt to gather the available information on subacute sclerosing panencephalitis (SSPE) in Southern Africa has produced records of 79 cases which have occurred since 1955. An important feature of the epidemiology is the clustering of 48 cases in the 5-year period 1970-1974. Thirty of these patients were resident in the Cape Province, and most of them were from the Coloured community. An SSPE registry will be maintained at the MRC Virus Research Unit of the University of Cape Town and an appeal is made to all practitioners to contribute any relevant data on patients with this disease.

An analysis of cases of subacute sclerosing panencephalitis (SSPE) in Southern Africa to the end of 1976 is presented. In the 2 years since the last report in 1975, 15 new cases have been added to the register. Seven patients from the Cape Province were investigated in Groote Schuur and Red Cross War Memorial Children's Hospitals in Cape Town and a recent postal survey revealed 6 cases in the Transvaal and 1 each from South West Africa and Rhodesia. This analysis indicates that the high incidence and temporal clustering of cases in the Cape Province is continuing, and that the relatively constant annual number of cases in the Transvaal and the apparent absence of the disease in Natal and the Orange Free State are being maintained.

Monohydroperoxides were isolated from chlorophyll-photosensitised oxidation of methyl oleate, methyl linoleate, methyl linolenate, and ethyl arachidonate. The positions of the hydroperoxide substituent were determined by two methods of analysis of the saturated hydroxy-esters formed by catalytic hydrogenation. Gas–liquid chromatographic analysis of degradation products and mass spectrometric analysis of the corresponding keto-esters both proved that the hydroperoxide groups are located at each of the carbon atoms which originally formed part of a double bond.