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Growing interest in quantum computing for practical applications has led to a surge in the availability of programmable machines for executing quantum algorithms1,2. Present-day photonic quantum computers3–7have been limited either to non-deterministic operation, low photon numbers and rates, or fixed random gate sequences. Here we introduce a full-stack hardware−software system for executing many-photon quantum circuit operations using integrated nanophotonics: a programmable chip, operating at room temperature and interfaced with a fully automated control system. The system enables remote users to execute quantum algorithms that require up to eight modes of strongly squeezed vacuum initialized as two-mode squeezed states in single temporal modes, a fully general and programmable four-mode interferometer, and photon number-resolving readout on all outputs. Detection of multi-photon events with photon numbers and rates exceeding any previous programmable quantum optical demonstration is made possible by strong squeezing and high sampling rates. We verify the non-classicality of the device output, and use the platform to carry out proof-of-principle demonstrations of three quantum algorithms: Gaussian boson sampling, molecular vibronic spectra and graph similarity8. These demonstrations validate the platform as a launchpad for scaling photonic technologies for quantum information processing.

Staphylococcus pseudintermediusis a well known commensal organism of dogs but also a canine opportunistic pathogen. Reports of this organism being recovered from specimens from humans might suggest an increase prevalence in human infections and/or improved diagnostic leading to more accurate identification. Here we report a case of persistent S. pseudintermediusinfection in an adult female oncology patient including colonization of the tip of an indwelling catheter. Diligence by laboratories in correctly isolating and identifying this pathogen (including susceptibility testing) is essential for optimal patient care.

We experimentally demonstrate stimulated four-wave mixing in two linearly uncoupled integrated $ {{\rm Si}_3}{{\rm N}_4} $Si_3N_4 micro-resonators. In our structure, the resonance combs of each resonator can be tuned independently, with the energy transfer from one resonator to the other occurring in the presence of a nonlinear interaction. This method allows flexible and efficient on-chip control of the nonlinear interaction, and is readily applicable to other third-order nonlinear phenomena.

Presents letters to the editor referencing articles and topics discussed in previous issues. "New Radicals in Dixie," which focused on the dangers of leftist organizations; "The Anarchists," which dealt with anarchism; "A Door Best Kept Closed," which focused on chemical weapons.

With almost half of all Americans now falling below the poverty line, or considered low income by government standards, formerly middleclass families are beginning to experience the reality behind the [...]

Standardized terminology for the porcine reproductive and respiratory syndrome virus (PRRSV) status of swine herds is necessary to facilitate communication between veterinarians, swine producers, genetic companies, and other industry participants. It is also required for implementation of regional and national efforts towards PRRSV control and elimination. The purpose of this paper is to provide a herd classification system for describing the PRRSV status of herds, based upon a set of definitions reflecting the biology and ecology of PRRSV. The herd classification system was developed by a definitions committee formed jointly by the American Association of Swine Veterinarians (AASV) and the United States Department of Agriculture PRRS-Coordinated Agricultural Project, and was approved by the AASV Board of Directors on March 9, 2010. The committee included veterinarians from private practice and industry, researchers, and representatives from AASV and the National Pork Board. Breeding herds, with or without growing pigs on the same premises, are categorized as Positive Unstable (Category I), Positive Stable (Category II), Provisional Negative (Category III), or Negative (Category IV) on the basis of herd shedding and exposure status. Growing-pig herds are categorized as Positive or Negative. Recommended testing procedures and decision rules for herd classification are detailed.

Allometric relationships between calcified structures and total length of round goby Neogobius melanostomuswere determined from a sample of fish ranging in total length from 53 to 152 mm. Each of the 10 allometric equations gave coefficients of determination (r2) that were greater than 0.80 and highly significant. The equations with the most predictive ability were those relating total length to cleithral, opercular, mouth, and pharyngeal bone measurements. Round goby remains were found in the stomachs of 10 predator species from the Bay of Quinte, Lake Ontario. Round goby were ingested most often by yellow perch Perca flavescens(40% of the stomachs examined) and largemouth bass Micropterus salmoides(27%) and less frequently by other predators. Round goby calcified structures most frequently found in the stomachs of predators were mouth parts (premaxilla and dentary), pharyngeal bones (dentigerous plate and pharyngobranchial plates), and otoliths. The predictive equations, diagnostic features of calcified structures, and list of predatory species in this study may serve as helpful tools for future analyses of round goby predator diets.

Interferons (IFNs) regulate the expression of genes that mediate their antiviral, antitumor, and immunomodulatory actions. We have previously shown that IFN-beta suppresses growth of human ovarian carcinoma xenografts in vivo and induces apoptosis of ovarian carcinoma cells in vitro. To investigate mechanisms of IFN-beta-induced apoptosis we employed an antisense technical knockout approach to identify gene products that mediate cell death and have isolated several regulators of interferon-induced death (RIDs). In this investigation, we have characterized one of the RIDs, RID-2. Sequence analysis revealed that RID-2 was identical to human inositol hexakisphosphate kinase 2 (IP6K2). IP6K2 is post-transcriptionally induced by IFN-beta in ovarian carcinoma cells. A mutant IP6K2 with substitutions in the putative inositol phosphate binding domain abrogates IFN-beta-induced apoptosis. These studies identify a novel function for IP6K2 in cell growth regulation and apoptosis.

Larval sea lampreys Petromyzon marinusin seven lampricide-treated streams were studied to assess the effects of density and abiotic factors on growth, length at metamorphosis, and age at metamorphosis. Support for density-dependent growth was not found in these streams. A linear relationship between total length and age was found for all populations. The daily growth of larvae in lampricide-treated streams was similar to that of populations that were never exposed to lampricide. Furthermore, the growth of stocked residual populations did not increase following a lampricide-induced reduction in larval density. Differences in growth and length at metamorphosis among these streams were accounted for by abiotic factors. Larval growth was highest in streams with an annual water temperature around 8°C, moderate discharge (0.5–2.0 m3/s), and high conductivity (>300µS). Length at metamorphosis, on the other hand, was inversely related to conductivity, annual discharge, and annual mean temperature. A model of age at metamorphosis based on larval growth and length at metamorphosis, both as functions of water temperature, showed that age at metamorphosis was lower for populations showing linear growth with age (typically low-density populations) than for those showing compensatory growth with age (typically high-density populations).

The effect on the polymerization kinetics of predissolving polystyrene polymers that have various molecular weights and end groups in styrene miniemulsions prepared using hexadecane as costabilizer was studied. It was noted that the rate of polymerization and number of droplets nucleated were affected by the molecular weight of the polymer that was predissolved. This dependence was attributed to a change in the number of droplets formed during homogenization as the molecular weight of the polymer was varied. However, the end group of the predissolved polymer did not have an affect on the kinetics. In all cases, predissolving polymer into a miniemulsion stabilized using hexadecane as costabilizer resulted in a much lower degree of enhancement in the kinetics compared to similar miniemulsion systems using cetyl alcohol as costabilizer. Since droplet sizes in miniemulsions containing hexadecane have been shown to be stable with time, unlike miniemulsions containing cetyl alcohol, these experiments were taken as evidence that the dominant cause for “enhanced droplet nucleation” is the preservation of droplet number prior to the addition of initiator.

Conventional nonsteroidal anti-inflammatory drugs inhibit both cyclooxygenase (Cox) isoforms (Cox-1 and Cox-2) and may be associated with nephrotoxicity. The present study was undertaken to assess the renal effects of the specific Cox-2 inhibitor, MK-966. Healthy older adults (n = 36) were admitted to a clinical research unit, placed on a fixed sodium intake, and randomized under double-blind conditions to receive the specific Cox-2 inhibitor, MK-966 (50 mg every day), a nonspecific Cox-1/Cox-2 inhibitor, indomethacin (50 mg t.i.d.), or placebo for 2 weeks. All treatments were well tolerated. Both active regimens were associated with a transient but significant decline in urinary sodium excretion during the first 72 h of treatment. Blood pressure and body weight did not change significantly in any group. The glomerular filtration rate (GFR) was decreased by indomethacin but was not changed significantly by MK-966 treatment. Thromboxane biosynthesis by platelets was inhibited by indomethacin only. The urinary excretion of the prostacyclin metabolite 2,3-dinor-6-keto prostaglandin F1alpha was decreased by both MK-966 and indomethacin and was unchanged by placebo. Cox-2 may play a role in the systemic biosynthesis of prostacyclin in healthy humans. Selective inhibition of Cox-2 by MK-966 caused a clinically insignificant and transient retention of sodium, but no depression of GFR. Inhibition of both Cox isoforms by indomethacin caused transient sodium retention and a decline in GFR. Our data suggest that acute sodium retention by nonsteroidal anti-inflammatory drugs in healthy elderly subjects is mediated by the inhibition of Cox-2, whereas depression of GFR is due to inhibition of Cox-1.

Predissolving polystyrene into the styrene monomer prior to homogenization in miniemulsions created using cetyl alcohol as the cosurfactant has been shown to result in a large increase in the polymerization rate and reduction in the particle size compared to similar systems with no predissolved polymer. This phenomenon has been termed “enhanced droplet nucleation”. The effects of varying the molecular weight and end group of the predissolved polystyrene in sodium lauryl sulfate/cetyl alcohol stabilized styrene miniemulsions are investigated here to gain a clearer understanding of this phenomenon. Predissolving polystyrene with either H or SO3^- end groups and molecular weights over a range from Mn = 39 000 to 206 000 g/mol results in the same level of enhancement in the kinetics independent of the polymer characteristics. This is taken as evidence against either a droplet surface modification or a change in droplet viscosity being the determining factor in “enhanced droplet nucleation”. However, measurement of the droplet size when no polymer is included indicates that these droplets undergo degradation by which the average size increases over time. Therefore, it is suggested the predominant cause of “enhanced droplet nucleation” from the addition of polymer is that the polymer adds extra stability to the miniemulsion droplets both prior to and during the polymerization. This is supported by calorimetric and particle size data.

The purified human placental alpha 2 beta 2 heterotetrameric insulin receptor complex was reduced and dissociated into functional alpha beta heterodimers by a combination of alkaline pH and dithiothreitol treatment. Insulin treatment of the isolated alpha beta heterodimeric complex was observed to induce the complete reassociation to an alpha 2 beta 2 heterotetrameric state when analyzed by nondenaturing Bio-Gel A-1.5m gel filtration chromatography. Nonreducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis of 125I-insulin affinity cross-linked and 32P-autophosphorylated alpha beta heterodimers demonstrated that the insulin-dependent reassociation to the alpha 2 beta 2 heterotetrameric state occurred both covalently and noncovalently under these conditions. Comparison by reducing and nonreducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the insulin-dependent covalent reassociation to an alpha 2 beta 2 heterotetrameric complex was due to the formation of a disulfide linkage(s) between the alpha beta heterodimers. beta subunit autophosphorylation of the control alpha 2 beta 2 heterotetrameric insulin receptor preparation was maximally stimulated within 5 min of insulin preincubation and occurred exclusively in the Mr = 400,000 alpha 2 beta 2 complex. Similarly, maximal insulin-stimulated beta subunit autophosphorylation of the alpha beta heterodimeric preparation occurred within 5 min of insulin pretreatment in the Mr = 210,000 alpha beta complex. However, 4 h of insulin pretreatment of the alpha beta heterodimer preparation induced the formation (6-fold) of a covalent 32P-labeled alpha 2 beta 2 heterotetrameric complex. Maximal stimulation of substrate phosphorylation for the alpha 2 beta 2 heterotetrameric complex was also observed to occur within 5 min of insulin treatment, whereas maximal insulin-stimulated substrate phosphorylation of the alpha beta heterodimeric complex required greater than 4 h. These data demonstrate that (i) insulin treatment can induce the reassociation of the alpha beta heterodimeric complex into a covalent alpha 2 beta 2 heterotetrameric state, and (ii) insulin-dependent protein kinase activation of the alpha beta heterodimeric insulin receptor correlates with the covalent reassociation into a disulfide-linked alpha 2 beta 2 heterotetrameric complex.

Previous studies have indicated that turkey erythrocyte and rat liver membranes contain endogenous alpha beta heterodimeric insulin receptors in addition to the disulphide-linked alpha 2 beta 2 heterotetrameric complexes characteristic of most cell types. We utilized 125I-insulin affinity cross-linking to examine the structural properties of insulin receptors from rat liver and turkey erythrocyte membranes prepared in the absence and presence of sulphydryl alkylating agents. Rat liver membranes prepared in the absence of sulphydryl alkylating agents displayed specific labelling of Mr 400,000 and 200,000 bands, corresponding to the alpha 2 beta 2 heterotetrameric and alpha beta heterodimeric insulin receptor complexes respectively. In contrast, affinity cross-linking of membranes prepared with iodoacetamide (IAN) or N-ethylmaleimide identified predominantly the alpha 2 beta 2 heterotetrameric insulin receptor complex. Similarly, affinity cross-linking and solubilization of intact turkey erythrocytes in the presence of IAN resulted in exclusive labelling of the alpha 2 beta 2 heterotetrameric insulin receptor complex, whereas in the absence of IAN both alpha 2 beta 2 and alpha beta species were observed. Turkey erythrocyte alpha 2 beta 2 heterotetrameric insulin receptors from IAN-protected membranes displayed a 3-4-fold stimulation of beta subunit autophosphorylation and substrate phosphorylation by insulin, equivalent to that observed in intact human placenta insulin receptors. Turkey erythrocyte alpha beta heterodimeric insulin receptors, prepared by defined pH/dithiothreitol treatment of IAN-protected membranes, were also fully competent in insulin-stimulated protein kinase activity compared with alpha beta heterodimeric human placenta receptors. In contrast, endogenous turkey erythrocyte alpha beta heterodimeric insulin receptors displayed basal protein kinase activity which was insulin-insensitive. These data indicate that native turkey erythrocyte and rat liver insulin receptors are structurally and functionally similar to alpha 2 beta 2 heterotetrameric human placenta insulin receptors. The alpha beta heterodimeric insulin receptors previously identified in these tissues most likely resulted from disulphide bond reduction and denaturation of the alpha 2 beta 2 holoreceptor complexes during membrane preparation.

A case-control study was conducted to examine the association of beta-haemolytic non-group A streptococci and pharyngitis in a paediatric population (n=502). No association could be found between disease and traditional Lancefield groups B, C, F, or G. When the analysis included the clustering of genetically related subgroups from different Lancefield groups, an association was evident for moderate and heavy quantitations of beta-haemolytic “large colony” group C and G streptococci (Streptococcus equisimilis and human biotypes of large colony group G streptococci) (p=0.021). This study further defines a subset of the beta-haemolytic non-group A streptococci that merit recognition by both the laboratory and physician.

A study of 12 streams draining forested and non-forested catchments was made in an area of central Scotland where slow-weathering bedrock was predominantly quartzite, schists and slates. Sitka spruce (Picea sitchensis Carriere) was the most common tree species. Precipitation in the area had an annual mean pH in the range 4.3–4.5. Streams within the planted zone were always more acid than those outside and had higher concentrations of aluminium and manganese. With one exception, trout were absent from streams within long-established forests and planted salmon eggs (Salmo salar L.) died within a few weeks. A high proportion of such eggs survived in streams outside the forest. Siphlonurus lacustris Eaton was the only mayfly nymph found in the most acid streams in summer collections. In winter samples, mayfly nymphs, Heptagenia lateralis (Curtis) were found in only one forest stream but several species were present in the non-forested catchments. It is suggested that spruce forests can effectively collect acid pollutants which are subsequently washed out, thus accelerating the acidification of the soil. Streams therefore become increasingly acid as the neutralisation capacities of their catchments decrease.

Insulin and Mn/MgATP treatment of immunoaffinity-purified αβ heterodimeric insulin receptors induced the formation of an α2β2heterotetrameric insulin receptor complex. In contrast, insulin-like growth factor-1 (IGF-1) treatment was completely ineffective in inducing the association of αβ heterodimeric insulin receptors. Similarly, IGF-1 or Mn/MgATP, but not insulin, treatment of immunoaffinity-purified αβ heterodimeric IGF-1 receptors induced the formation of an α2β2heterotetrameric IGF-1 receptor complex. A monoclonal antibody specific for the insulin receptor (MA5) completely immunoprecipitated all the insulin binding activity from both the α2β2heterotetrameric and αβ heterodimeric insulin receptor complexes but did not immunoprecipitate IGF-1 receptors. Conversely, the IGF-1 receptor-specific monoclonal antibody (αIR-3) immunoprecipitated all the IGF-1 binding activity, but not insulin receptors.

It is now some 4 years since the New South Wales Roads and Traffic Authority (RTA) interim noise policy was released. The document sets out RTA policies on traffic noise along with guidelines relating to assessment and control. It is perhaps the most extensive document on the topic ever produced by an Australian road authority. The underlying philosophy of the policy is the importance of noise as an issue that must be addressed in all aspects of RTA road planning, design, construction, maintenance, and operation programs. Some recent advances in the traffic noise arena are considered. A spatial decision support system is then outlined for road planning that has been developed as part of an Australian Research Council industry collaborative research grant involving RTA and the University of New South Wales. This is built on object-oriented programming and geographic information system technologies and involves a library containing models in eight domains amounting to 33,000 lines of code. The noise estimation procedure included in this system is described together with how it has been adapted and implemented in an object-oriented way. Speculation is made on how the prototype may be integrated into the emerging corporate responsibilities of RTA in the area of communication and consultation.

A positive association between the use of artificial sweeteners, particularly saccharin, and risk of bladder cancer in males has been observed in a case-control study of 480 men and 152 women in three Provinces in Canada. The risk ratio for ever versus never used is 1·6 for males (p=0·009, onetailed test), and a significant dose-response relationship was obtained for both duration and frequency of use. The population attributable risk for males is estimated at 7%, though for diabetics, who have a similar risk ratio for artificial sweetener use as non-diabetics, the attributable risk is 33%.

The diversity of statoliths and changes in statolith length were examined in larval and metamorphosing sea lampreys Petromyzon marinasfrom four streams in Ontario. In midsummer, increases in statolith lengths were similarly and positively correlated with larval total lengths in the four streams. Statoliths from larval and metamorphosing lampreys collected from Lynde and Farewell creeks in June and September displayed typical alternating opaque and translucent bands. The number of opaque bands, or annuli, provided reliable age estimates when compared with length-frequency distributions. In July and September, statoliths from some larval and metamorphosing lampreys collected from West Root River and Cannon Creek were either absent or did not have typical bands, hence they did not always provide reliable ages. The diversity of statoliths appears to be related to ambient calcium ion concentrations, especially during periods of rapid larval growth. The use of statoliths is sometimes the only method to age some populations of sea lampreys because of ambiguity in length-frequency distributions. The absence of statoliths, as encountered in this study, has potential management implications when determining age-at-metamorphosis.

Two possible methods for monitoring exposure to 2,4-difluoroaniline and 4-fluoroaniline have been investigated: measurement of methaemoglobin content in blood and measurement of urinary metabolites. Experiments using rats dosed by the oral route as a model system show that measurement of methaemoglobin content provides a very rapid and simple monitoring method, but is not very sensitive. Measurement of the ortho-hydroxy metabolites of the two compounds, as their benzoxazole derivatives, provides a much more sensitive, but complicated technique. Details of both methods are presented.

Occupational therapists, physicians and others evince an appreciation of the relationship between balanced lifestyles and health, but there are few studies that concentrate on balance as a key issue. This paper reports on a pilot study that tested the effectiveness of a questionnaire to explore perceptions of occupational balance and its relationship to health. The ultimate aim is to provide information that may assist clients, or the population in general, about potentially healthily balanced configurations of occupation. Using a cluster sampling method and with 146 respondents the results of a questionnaire indicated that, for many of these respondents, perceived ideal occupational balance is approximately equal involvement in physical, mental, social and rest occupations. A correlation between reported good health and the closeness of current occupational patterns to the ideal was statistically significant. These promising results warrant further investigation. Copyright © 1997 Whurr Publishers Ltd.

To localize the origin-specific DNA-binding domain on the simian virus 40 tumor (T) antigen molecule, we used limited proteolysis with trypsin to generate fractional peptides for analysis. A 17,000-Mr peptide was found to be capable of binding not only to calf thymus DNA, but also specifically to the simian virus 40 origin of DNA replication. This approximately 130-amino-acid peptide was derived from the extreme N-terminus of the T antigen and represented less than one-fifth of the entire molecule. The coding sequence for this tryptic peptide was located approximately between 0.51 and 0.67 map units (excluding the intron, which maps between 0.54 and 0.59). Since the first 82 amino acids are shared between large T and small t antigens, and since the latter does not bind DNA, it can be concluded that the sequence between isoleucine 83 and approximately arginine 130 is necessary for origin-specific binding by the T antigen. We also observed that in vivo phosphorylation of the T antigen within this region completely abolished the ability of the 17,000-Mr peptide to bind DNA. This observation is consistent with the idea that DNA binding by the T antigen is regulated by posttranslational modifications.

We recently identified a novel 8-kDa transmembrane protein, Mat-8, that is expressed in a subset of murine breast tumors. We have now cloned a cDNA encoding the human version of Mat-8 and show that it is expressed both in primary human breast tumors and in human breast tumor cell lines. The extracellular and transmembrane domains of Mat-8 are homologous to those of phospholemman (PLM), the major plasmalemmal substrate for cAMP-dependent protein kinase and protein kinase C in several different tissues. PLM, which induces chloride currents when expressed in Xenopus oocytes, contains consensus phosphorylation sites for both cAMP-dependent protein kinase A and protein kinase C in its cytoplasmic domain. In contrast, the cytoplasmic domain of Mat-8 contains no such consensus phosphorylation sites and is, in fact, unrelated to the cytoplasmic domain of PLM. RNA blot analysis reveals that Mat-8 and PLM exhibit distinct tissue-specific patterns of expression. We show that expression of Mat-8 in Xenopus oocytes induces hyperpolarization-activated chloride currents similar to those induced by PLM expression. These findings suggest that Mat-8 and PLM, the products of distinct genes, are related proteins that serve as Cl- channels or Cl- channel regulators but have different roles in cell and organ physiology.

The high-frequency rheology of concentrated liquid charge-stabilized dispersions has been measured using a surface-loaded torsional resonator. The high-frequency shear moduli are extracted from the measurement as a function of ionic strength and surface acid content. A theory which enables the determination of the effective surface charge of the concentrated dispersions is presented. At high ionic strengths the theory simplifies to an analytic formula relating the effective surface charge to the high-frequency limiting shear modulus in terms of an effective hard-sphere diameter. The effective hard-sphere diameter is obtained experimentally from the high concentration asymptote of the zero-shear viscosity. The resulting effective surface charge increases with added electrolyte content in agreement with charge renormalization theory. The effective charge also increases with added weak and strong surface acid content. The method, which operates on concentrated dispersions, is found to yield effective charges that agree with dilute measurements of the electrophoretic mobility. Moreover, the effective hard-sphere scaling reduces the high-frequency viscosity to a master curve independent of salt content.

Classical insulin and insulin-like growth factor I (IGF-I) receptors exist as well defined alpha 2 beta 2 heterotetrameric complexes that are assembled from two identical alpha beta heterodimeric half-receptor precursors. Recent evidence suggests that insulin and IGF-I half-receptors can heterologously assemble to form alpha 2 beta 2 insulin/IGF-I hybrid receptor complexes in vivo and in vitro. We have utilized hybrid receptor complexes to examine ligand-stimulated transmembrane signaling of wild-type insulin (alpha beta INS.WT) or IGF-I (alpha beta IGF.WT) half-receptors assembled with a kinase-defective insulin half-receptor mutant (alpha beta INS.A/K). In vitro assembly of either (alpha beta)IGF.WT/(alpha beta)INS.A/K or (alpha beta)INS.WT/(alpha beta)INS.A/K hybrid receptors resulted in decreased substrate protein kinase activity. The degree of protein kinase inactivation directly correlated with the amount of immunologically cross-reactive hybrid receptors formed. In contrast to substrate kinase activity, insulin-stimulated autophosphorylation of the (alpha beta)INS.WT/(alpha beta)INS.A/K hybrid receptor complex was completely unaffected in comparison to the wild-type (alpha beta)INS.WT/(alpha beta)INS.WT receptor. To assess a molecular basis for this difference, autophosphorylation of a hybrid receptor composed of a truncated beta-subunit insulin half-receptor with the kinase-defective half-receptor, (alpha beta)INS. delta CT/(alpha beta)INS.A/K, demonstrated the exclusive autophosphorylation of the (alpha beta)INS.A/K half-receptor beta subunit. These results demonstrate that ligand-dependent substrate phosphorylation by insulin and IGF-I holoreceptors requires interactions between two functional beta subunits within the alpha 2 beta 2 heterotetrameric complex and occurs through an intramolecular trans-phosphorylation reaction.

A subgroup analysis of 613 specimens submitted to the British Columbia's Children's Hospital from 1987 to 1992 revealed that subgroups A and B of respiratory syncytial virus (RSV) were both circulating in our community, with some predominance for subgroup A during the period from October 1987 to September 1988 (the 1987-88 season) (64%), 1990-91 (60%), and 1991-92 (62%). During 1989-90 subgroup A represented the majority of isolates (80%). Subgroup B predominated during only one season, 1988-89 (94%). No microheterogeneity within subgroups was apparent as judged by the monoclonal antibody reactivity pattern. More male than female children were affected overall, but no sex-related difference between subgroup infections could be detected (P = 0.28). The majority of patients were less than 1 year of age, and no significant association between age and subgroup was detected after stratifying for year (P = 0.64). This is, to our knowledge, the first comprehensive longitudinal RSV subgroup prevalence study from the Pacific Northwest and from Canada.

To investigate the role of subunit communication in the insulin binding and tyrosine-specific protein kinase activities of the purified human placental insulin receptor, we have developed the methodology to isolate a functional alpha beta heterodimeric insulin receptor complex from the native alpha 2 beta 2 heterotetrameric disulfide-linked state. The dissociation of the alpha 2 beta 2 heterotetrameric insulin receptor into an alpha beta heterodimer was found to be approximately 50% efficient by treatment with alkaline pH (8.75) and dithiothreitol (2 mM). Removal of the dithiothreitol and pH neutralization (pH 7.60) by rapid Sephadex G-50 gel filtration resulted in the preservation of tracer insulin binding activity. The nondissociated alpha 2 beta 2 heterotetrameric and alpha beta heterodimeric insulin receptor complexes could then be effectively separated by Bio-Gel A-1.5m gel filtration. Scatchard analyses of insulin binding to the alpha 2 beta 2 heterotetrameric control or dithiothreitol-treated but nondissociated alpha 2 beta 2 heterotetrameric insulin receptor complexes demonstrated a curvilinear binding isotherm with a maximum of 1 mol of insulin bound/mol of alpha 2 beta 2 heterotetrameric complex. However, binding analyses performed on the isolated alpha beta heterodimeric complex yielded a nearly linear binding curve also, with 1 mol of insulin bound/mol of alpha beta heterodimeric complex at saturation. These data demonstrate that the insulin half-site binding reactivity observed in the alpha 2 beta 2 heterotetrameric insulin receptor complex results from either an asymmetric assembly of identical alpha beta heterodimers or from absolute negative cooperativity.

A counterimmunoelectrophoresis test for Pneumocystis carinii antigenemia was employed to assess the extent of subclinical infection or colonization with this agent in adults with infection, pulmonary disease, or malignancy and in healthy homosexual men. Antigenemia was detected in 6 of 208 (3%) of normal controls, 3 of 28 (11%) of patients with pulmonary infection, 3 of 33 (9%) of those with chronic lung disease, 1 of 36 (3%) of patients with lung cancer, 7 of 271 (3%) of afebrile subjects with malignancy, 6 of 19 (32%) of febrile patients with malignancy, 2 of 22 (9%) of those with nonpulmonary infection, and 0 of 21 (0%) of healthy young homosexual men. These data suggest that P. carinii is a common commensal or saprophyte that becomes clinically significant only when host defenses are impaired. Antigenemia may occur intermittently during various disease states in the absence of positive clinical signs and should alert the physician to subacute infection or colonization. Treatment appears advisable when clinical data and counterimmunoelectrophoresis results concur.

Four streams in the Loch Ard Forest in central Scotland dried out almost completely during a drought in the summer of 1984. The recovery of the invertebrate populations in the streams was studied from September 1984 until March 1985 when most of the insect larvae and nymphs were almost full-grown.

A technique has been developed for measuring total water mixing ratio and condensed water mixing ratio in warm-based convective clouds. The jet engine compressor on a Learjet 24 is employed as an evaporator to convert all cloud condensate to vapour and the vapour density in the compressed (bleed) air is measured with a Lyman-alpha humidiometer.

We have extended these observations to examine the role of polylysine on the divalent metal ion requirement for ligand-stimulated protein kinase activity and the transmembrane signaling mechanism of both the human placenta insulin and insulin-like growth factor 1 (IGF-1) receptors. Polylysine (0.2–1 µM) was found to activate maximally the α2β2heterotetrameric insulin receptor autophosphorylation and exogenous substrate protein kinase activity 25–50-fold in the presence of insulin without significantly affecting the basal protein kinase activity in the absence of insulin. The polylysine-dependent insulin stimulation of protein kinase activity required the presence of both magnesium and manganese but at relatively low divalent metal ion concentrations (0.1 mM) compared to the typical 2–10 mMMg/Mn used in the standard in vitrokinase assays. The stimulation of the insulin receptor kinase by insulin in the presence of polylysine occurred primarily due to an increase in Vmaxwith no significant effect on the Kmfor ATP. In addition, autophosphorylated insulin receptors which are protein kinase-active and insulin-independent at high metal ion concentrations still displayed the polylysine-dependent insulin stimulation of protein kinase activity to the same extent as nonphosphorylated insulin receptors at low Mg/Mn (0.1 mM) concentrations. Surprisingly, polylysine was completely unable to stimulate the IGF-1-dependent protein kinase activity of the homologous human placenta IGF-1 receptor. These data suggest that the insulin receptor tyrosine-specific protein kinase activity may be regulated by unique endogenous basic proteins that are distinct from those which modify the IGF-1 receptor.

Before the commissioning of SPring‐8, the in‐vacuum hybrid undulator developed at SPring‐8 had been brought to the ESRF for the first beam test in the summer of 1996. The purpose of this test was to investigate the influence of the in‐vacuum undulator on the beam and check its vacuum system. However, heating by the resistive wall impedance turned out to be a critical issue for the in‐vacuum undulators.