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The crystal structure of Pseudomonas cellulosa mannanase 26A has been solved by multiple isomorphous replacement and refined at 1.85 A resolution to an R-factor of 0.182 (R-free = 0.211). The enzyme comprises (beta/alpha)(8)-barrel architecture with two catalytic glutamates at the ends of beta-strands 4 and 7 in precisely the same location as the corresponding glutamates in other 4/7-superfamily glycoside hydrolase enzymes (clan GH-A glycoside hydrolases). The family 26 glycoside hydrolases are therefore members of clan GH-A. Functional analyses of mannanase 26A, informed by the crystal structure of the enzyme, provided important insights into the role of residues close to the catalytic glutamates. These data showed that Trp-360 played a critical role in binding substrate at the -1 subsite, whereas Tyr-285 was important to the function of the nucleophile catalyst. His-211 in mannanase 26A does not have the same function as the equivalent asparagine in the other GH-A enzymes. The data also suggest that Trp-217 and Trp-162 are important for the activity of mannanase 26A against mannooligosaccharides but are less important for activity against polysaccharides.

We report the discovery of the most complex arcsec‐scale radio gravitational lens system yet known. B1933+503 was found during the course of the CLASS survey and MERLIN and VLA radio maps reveal up to 10 components. Four of these are compact and have flat spectra; the rest are more extended and have steep spectra. The background lensed object appears to consist of a flat‐spectrum core (quadruply imaged) and two compact ‘lobes’ symmetrically disposed relative to the core. One of the lobes is quadruply imaged while the other is doubly imaged. An HSTobservation of the system with the WFPC2 shows a galaxy with an axial ratio of 0.5, but none of the images of the background object is detected. A redshift of 0.755 has been measured for the lens galaxy.

A new reflecting surface that re-orients a line-source through an angle of90\degis discussed. Several curves on the surface are simple parabolas and ellipses, but the expression for an arbitrary curve on the surface is a fourth-order equation. The curves are derived by preserving phase relationship between the line source and the rotated line using geometrical optics. The intensity distribution on the rotated line is found by numerical integration.

Signal transduction through the T-cell receptor and cytokine receptors on the surface of T lymphocytes occurs largely via tyrosine phosphorylation of intracellular substrates. Because neither the T-cell receptor nor cytokine receptors contain intrinsic kinase domains, signal transduction is thought to occur via association of these receptors with intracellular protein tyrosine kinases. Although several members of the SRC and SYK families of tyrosine kinases have been implicated in signal transduction in lymphocytes, it seems likely that additional tyrosine kinases involved in signal transduction remain to be identified. To identify unique T-cell tyrosine kinases, we used polymerase chain reaction-based cloning with degenerate oligonucleotides directed at highly conserved motifs of tyrosine kinase domains. We have cloned the complete cDNA for a unique human tyrosine kinase that is expressed mainly in T lymphocytes (EMT) and natural killer (NK) cells. The cDNA of EMT predicts an open reading frame of 1866 bp encoding a protein with a predicted size of 72 Kd, which is in keeping with its size on Western blotting. A single 6.2-kb EMT mRNA and 72-Kd protein were detected in T lymphocytes and NK-like cell lines, but were not detected in other cell lineages. EMT contains both SH2 and SH3 domains, as do many other intracellular kinases. EMT does not contain the N-terminal myristylation site or the negative regulatory tyrosine phosphorylation site in its carboxyterminus that are found in the SRC family of tyrosine kinases. EMT is related to the B-cell progenitor kinase (BPK), which has recently been implicated in X-linked hypogammaglobulinemia, to the TECI mammalian kinase, which has been implicated in liver neoplasia, to the more widely expressed TECII mammalian kinase, and to the Drosophila melanogaster Dsrc28 kinase. Sequence comparison suggests that EMT is likely the human homologue of a recently identified murine interleukin-2 (IL-2)-inducible T cell kinase (ITK). However, unlike ITK, EMT message and protein levels do not vary markedly on stimulation of human IL-2-responsive T cells with IL-2. Taken together, it seems that EMT is a member of a new family of intracellular kinases that includes BPK, TECI, and TECII. EMT was localized to chromosome 5q31–32, a region that contains the genes for several growth factors and receptors as well as early activation genes, particularly those involved in the hematopoietic system. Furthermore, the 5q31–32 region is implicated in the genesis of the 5q- syndrome associated with myelodysplasia and development of leukemia.(ABSTRACT TRUNCATED AT 400 WORDS)

National curriculum assessment at Key stage 1 is likely to generate anxiety in teachers, if for no other reason than it is a new experience. Local arrangements and procedures are new, untested and may well need modification in the light of experience. The educational psychologist in visiting schools is likely to be faced with questions never previously posed. Hampshire have attempted to preempt some of the issues and build them into the Inservice development of the service. This article outlines the approach taken.

A three year study, started in Spring 1985, is intended toreveal the intellectual, ethical and interpersonal development of medical students at a large Canadian university during their undergraduate medical education and the extent of congruence between these changes and the developmental changes in students anticipated by the Faculty of Medicine. It is intended also that the authors will examine the extent to which characteristics of the medical school learning environment (a) are supportive of desired and anticipated student developmental changes, (b) are related to observed student changes and (c) are consistent with the Faculty mission and the premises and objectives of the undergraduate medical curriculum.This report describes one phase of the larger study, specifically, the perceptions of the learning environment obtained from 51 of 57 faculty who serve as Undergraduate Course Supervisors. Analysis and interpretation of these perceptions with reference to the goals and objectives of the larger study are also provided.

In mosn mnedical schools intellectual, interpersonal, and ethical development of students are ti/e core constituents of statements of educational goals and objectives. Paradoxica/lk; it inay be that the dominant features of the educational environments of these schools serve to inhibit student development in these areas. T/iis report describes one of a series of inivestigations, carried out at the Faculty of Medicinie of a large Canadian university, testing the hypothesis of a mismatch between educational goals and the educational environiment. In this study the perceptions of course and topic supervisors, who are responsible for t/ie planning, coordination, presentation, and evaluation of the discrete courses thai make tip the undergraduate medical curriculum, are described and analyzed with reference to A rgyris and Schon 's Model 1 and Model 2 definitions of institutional environmnents.

An innovative program, introduced into a tradition-based undergraduate medical school curriculum, was evaluated using an ethnographic approach for data collection and analysis. The objective of theevaluation study was to provide data in support of rational decision making with respect to the future of the innovation. This article describes the methodology andprocesses used to evaluate the innovation and assesses the strengths and weaknesses of the evaluation.

We have isolated from a human thymus cDNA library a cDNA clone encoding a potential protein with 54% amino acid similarity to that encoded by a previously identified cDNA for yeast nucleosome assembly protein I (NAP-I). The deduced amino acid sequence for this newly identified cDNA, designated hNRP (human NAP-related protein), contains a potential seven-residue nuclear localization motif, three clusters of highly acidic residues and other structural features found in various proteins implicated in chromatin formation. When expressed as a fusion protein in Escherichia coli, hNRP reacted specifically with a monoclonal antibody raised against human NAP-I. The hNRP transcript was detected in all tissues and cell lines studied, but levels were somewhat increased in rapidly proliferating cells. Moreover, levels of both hNRP mRNA and protein increased rapidly in cultured T-lymphocytes induced to proliferate by incubation with phorbol ester and ionomycin. Phorbol 12-myristate 13-acetate/ionomycin-induced increases in both hNRP mRNA and mitogenesis, as measured by thymidine incorporation, were markedly inhibited, however, in cells treated with an hNRP antisense oligonucleotide. These results demonstrate a correlation between induction of hNRP expression and mitogenesis and taken together with the structural similarities between hNRP and yeast NAP-I suggest that the hNRP gene product participates in DNA replication and thereby plays an important role in the process of cell proliferation.

The increasing volume of remotely-sensed data has led to a need for efficient automatic analysis procedures. A system is presented for automatic, knowledge-based segmentation of remotely-sensed images of the land. The system uses the information in time sequences of remotely-sensed data together with cartographic map data and domain expertise to build a model of the scene in terms of segments and their possible classes. The accuracies of segmentation and subsequent classification are shown to be superior to traditional automatic techniques. In addition, potential changes in the scene are isolated.

We use broadband photometry and low-resolution spectra of a complete sample of late-K and M dwarfs brighter than I=22 in three fields at high galactic latitude to study issues relating to galactic structure and large scale abundance gradients in the Galaxy. The observed starcounts in each field are a good match to the predictions of models based on deep starcount data in other intermediate-latitude fields, and these models identify the late-type stars as members of the Galactic disk. Abundances for these late type stars are estimated via narrowband indices that measure the strength of the TiO and CaH bands in their spectra. Our results show that the average abundance in the Galactic disk remains close to solar even at heights of more than 2 kpc above the Plane.

We have assigned a human β-crystallin gene, HuβA3/A1 (gene symbol: CRYB1), to chromosome 17 using a panel of 19 human-hamster somatic cell hybrids and blot-hybridization analysis of cell hybrid DNA. Positive probe-hybridization signal was detected in a hybrid that had lost the short arm of human chromosome 17 but retained the long arm, translocated to a hamster chromosome. In addition, in situ hybridization analysis of metaphase chromosome spreads of this cell line suggested that the most probable location for CR YB1 is on the long arm of chromosome 17, in the region q21.

The current state of professional training and development for educational psychologists in the UK has been heavily influenced by the changing role demands of the 1980s. This article describes the work in educational psychology training which is currently being carried out at Southampton University. The uniquely 'integrated' nature of the Southampton model is discussed and details of the organization of the three phases - preprofessional training, professional training and advanced professional training/ development - are provided. Changes which have occurred as a result of ongoing evaluation are outlined and likely future trends are identified. Finally, it is argued that professional training and development initiatives should not only respond to external demands but should also attempt to shape educational psychology practice in the 1990s.

1. The occurrence of mineralised tendons in the wing and pelvic limb of the domestic fowl was studied radiographically in adults and in growing birds from hatching to 182 d.2. Mineralised tendons were found to occur in all the adults in the dorsal and plantar tarsometatarsus and variably in the caudal tibiotarsus, cranial metacarpus and caudal antebrachium. In the cranial tibiotarsus a mineralised tendon was detected in two cockerels only.3. Mineralisation, was detected from 91 d onwards, at first in tendons in the plantar tarsometatarsus and cranial metacarpus and later in the dorsal tarsometatarsus. The mineralised tendons found in adults at other sites were not found during the growing period studied.

My first contact with the IEEE was in 1947 when, at the University of Western Ontario in London, Canada, under the guidance of Professor Garfield A. Woonton, I became a student member. In my college senior year (1949), my seminar topic was broadly titled, "Radio Wave Propagation": ground-wave, ionospheric, tropospheric - all were included! I was soon to learn that it was overwhelming to encompass such a broad field in detail. I think some of the inspiration for this interest in propagation came through J.A. Ratcliffe, whom I met briefly in England during the early (1941) radar years. He recently finished his days at Cambridge University.

Remotely-sensed data constitute a major potential source of input to geographical information systems (GIS)However, these data often have a relatively poor classification accuracy compared with that of the cartographic data from maps with which they may be combined in the course of GIS analysis. The possibility exists of using data sets (in the form of digital maps) resident within a GIS in order to improve this accuracy, before the classified image is incorporated into the GIS. Results are discussed from a British Alvey Information Technology project to develop a system for the knowledge-based segmentation and classification of remotely-sensed terrain images, in which the knowledge contained in digital map

We report here the detailed structure of a human beta-crystallin gene, designated Hu beta A3/A1, which was isolated and characterized using homologous mouse and bovine beta-crystallin cDNAs. Hu beta A3/A1 consists of six exons, spanning approximately 8 kilobases. The first two exons code for an N-terminal extension of 32 amino acid residues, while the other four encode the four similar structural motifs of the predicted polypeptide. Sequence homologies among the latter four exons and their intron-exon junctions support a model of gene evolution based on two successive exon duplications. Transcription of Hu beta A3/A1 in the eye lens initiates 24 base pairs downstream of a putative TATA box and just 7 nucleotides upstream of a potential initiation codon, generating a single mRNA of approximately 1 kilobase. Comparison of Hu beta A3/A1 with the homologous bovine cDNA and the translation products of the corresponding bovine gene suggests that translation of Hu beta A3/A1 commences at either of two potential initiation codons located in the first and second exons. Differential use of these two codons predicts two polypeptides differing by the presence or absence of 17 amino acid residues at their N-termini.

1. Amino acid-sequence studies were done on a peptide of mol.wt. approx. 12500 that was isolated from the highly helical fragments obtained by partial chymotryptic digestion of the low-sulphur proteins (S-carboxymethylkerateine-A) from wool. 2. The peptides obtained by tryptic and chymotryptic digestion of this large peptide were separated by ion-exchange chromatography on DEAE-cellulose at pH8.5 with an (NH4)(2)CO(3) concentration gradient and, where necessary, purified further by paper electrophoresis. 3. Determination of the sequences of many of these peptides showed that a high proportion of the cationic residues occurs in pairs. 4. Although two of the four S-carboxymethylcysteine residues are located in what appears to be a non-helical region near the N-terminus the other two S-carboxymethylcysteine residues occur in or near sequences suggesting a helical conformation. 5. Some peptides were obtained, in low yields, that appeared to be homologues of more major ones. These suggest either homologies in the helical portions of the low-sulphur proteins or the presence of closely related amino acid sequences in helical regions of completely different origins. 6. A partial sequence of the complete peptide is proposed.

Lactoperoxidase (EC 1.11.1.7) catalysed the oxidation of NADH by hydrogen peroxide in the presence of either thiocyanate, iodide or bromide. In the presence of thiocyanate, net oxidation of thiocyanate occurred simultaneously with the oxidation of NADH, but in the presence of iodide or bromide, only the oxidation of NADH occurred to a significant extent. In the presence of thiocyanate or bromide, NADH was oxidized to NAD+ but in the presence of iodide, an oxidation product with spectral and chemical properties distinct from NAD+ was formed. Thiocyanate, iodide and bromide appeared to function in the oxidation of NADH by themselves being oxidized to products which in turn oxidized NADH, rather than by activating the enzyme. Iodine, which oxidized NADH non-enzymically, appeared to be an intermediate in the oxidation of NADH in the presence of iodide. NADPH was oxidized similarly under the same conditions. An assessment was made of the rates of these oxidation reactions, together with the rates of other lactoperoxidase-catalysed reactions, at physiological concentrations of thiocyanate, iodide and bromide. The results indicated that in milk and saliva the oxidation of thiocyanate to a bacterial inhibitor was likely to predominate over the oxidation of NADH.

Lactoperoxidase (EC 1.11.1.7), an enzyme present in various mammalian glands and in their secretions, catalyses the oxidation of thiocyanate by hydrogen peroxide to form a compound that inhibits the growth, oxygen uptake and acid production of certain bacteria. This compound was found to be too unstable to isolate in pure form, but its properties in dilute aqueous solution were studied with a view to establishing its identity. At thiocyanate concentrations of approximately 1mm, formation of the inhibitor, which took place by a nonstoicheiometric reaction, was maximal when an approximately equimolar amount of hydrogen peroxide was added. Excess of hydrogen peroxide oxidized the inhibitor to sulphate and cyanate. The inhibitor displayed a polarographic reduction wave of which the half-wave potential was pH-dependent. Studies of the variation of the polarographic half-wave potential and of the u.v. extinction with pH indicated that the inhibitor existed in an acid–base equilibrium (pKa 5.1±0.1). The inhibitor decomposed by a mechanism involving H+ ions and thiocyanate, the kinetics varying according to whether the inhibitor was in its acidic or basic form. From these studies it was concluded that the inhibitor was either cyanosulphurous acid (HO2SCN) or cyanosulphuric acid (HO3SCN).

The formation of hydrogen peroxide by group N streptococci was found to occur through the action of a reduced nicotinamide adenine dinucleotide (NADH) oxidase which catalyzed the oxidation of NADH by molecular oxygen. The enzyme was activated by flavine adenine dinucleotide. Whereas some of the hydrogen peroxide formed was removed through the action of an NADH peroxidase, sufficient accumulated in media to inhibit the growth, respiration, and viability of these organisms. The amount of hydrogen peroxide which accumulated varied among strains, and this variation could be related to differences in the properties of the NADH oxidase present.

One hundred and forty-three students and 18 faculty at the University of Toronto participated in a study of the anaesthesia simulator as an evaluation tool. Both student and faculty opinions regarding the experience were elicited using questionnaires with a five-point scale, 1 = strongly disagree, 5 = strongly agree. Faculty and student opinion were similar and positive with respect to the use of the simulator and matching of educational objectives, its use as a learning experience, its use as an evaluation tool and the need for familiarity with the tool before use as an assessment method. This study supports the use of the simulator as an evaluation tool based on faculty and student opinions provided that prior exposure to the environment is offered.

The latest review of consultations by the College and Association of Registered Nurses of Alberta (CARNA) indicates that concerns related to scope of practice and nursing practice standards are on the rise.Consultations were initiated by phone, fax, e-mail or in person by registered nurses (RNs), employers, or others who sought assistance with issues that directly or indirectly affected the delivery of safe, competent and ethical nursing care.The latest review is based on 862 consultations conducted between Oct. 1, 2005 and Sept. 30, 2006. The comparison is made from the previous year reviewed (Oct. 1, 2004-Sept. 30, 2005) consisting of a total of 917 calls. [ABSTRACT FROM AUTHOR]