Direct Neighbourhood Research Articles

Polymer‐Analogous Preparation of Cellulose Tricarbanilates: Mechanisms of Degradation in Dimethylsulfoxide

AbstractTwo cellulose samples were subject to treatment with phenylisocyanate (PhNCO), both in pyridine and in dimethylsulfoxide (DMSO). In each case, DMSO degraded cellulose in an extent depending on the derivatized cellulose. The formation of dimethylsulfonium ions was recognized as the cause leading to an oxidation of hydroxyl groups. This Pfitzner‐Moffatt type oxidation is dependent on carboxyl groups and therefore occurs most probably in their neighbourhood. It was deduced that formation of oxidised sections along the cellulose chains occurs containing either carbonyl and carboxyl groups in the same anhydroglucose unit (AGU) or singly oxidised AGUs in direct neighbourhood to each other. This leads to much facilitated eliminative degradation.

Inclining the Purine Base Binding Plane in Protein Kinase CK2 by Exchanging the Flanking Side-chains Generates a Preference for ATP as a Cosubstrate

Protein kinase CK2 (casein kinase 2) is a highly conserved and ubiquitously found eukaryotic serine/threonine kinase that plays a role in various cellular key processes like proliferation, apoptosis and circadian rhythm. One of its prominent biochemical properties is its ability to use GTP as well as ATP as a cosubstrate (dual-cosubstrate specificity). This feature is exceptional among eukaryotic protein kinases, and its biological significance is unknown. We describe here a mutant of the catalytic subunit of protein kinase CK2 (CK2alpha) from Homo sapiens (hsCK2alpha) with a clear and CK2-atypical preference for ATP compared to GTP. This mutant was designed on the basis of several structures of CK2alpha from Zea mays (zmCK2alpha) in complex with various ATP-competitive ligands. A structural overlay revealed the existence of a "purine base binding plane" harbouring the planar moiety of the respective ligand like the purine base of ATP and GTP. This purine base binding plane is sandwiched between the side-chains of Ile66 (Val66 in hsCK2alpha) and Met163, and it adopts a significantly different orientation than in prominent homologues like cAMP-dependent protein kinase (CAPK). By exchanging these two flanking amino acids (Val66Ala, Met163Leu) in hsCK2alpha(1-335), a C-terminally truncated variant of hsCK2alpha, the cosubstrate specificity shifted in the expected direction so that the mutant strongly favours ATP. A structure determination of the mutant in complex with an ATP-analogue confirmed the predicted change of the purine base binding plane orientation. An unexpected but in retrospect plausible consequence of the mutagenesis was, that the helix alpha D region, which is in the direct neighbourhood of the ATP-binding site, has adopted a conformation that is more similar to CAPK and less favourable for binding of GTP. These findings demonstrate that CK2alpha possesses sophisticated structural adaptations in favour of dual-cosubstrate specificity, suggesting that this property could be of biological significance.

Mantle viscosity inference: a comparison between simulated annealing and neighbourhood algorithm inversion methods

SUMMARY Two direct search methods, simulated annealing and neighbourhood algorithm, are applied to the inversion of the viscosity profile of the mantle using relative sea level time-histories for the Hudson Bay region. In problems characterized by a low-dimensional model space (Nd= 2 in this study), the two inversion methods show comparable performances. When a larger number of dimensions is involved (specifically Nd= 6), we directly show that simulated annealing is less effective than neighbourhood algorithm in overcoming the obstacles that are found in the model space when our specific data set is employed. This study confirms that modifications of the conventional Monte Carlo inversion method, such as simulated annealing and neighbourhood algorithm, are viable tools to determine the viscosity profile of the mantle, which, until recently, has been mainly tackled by means of linearized techniques.

Simulation of pedestrian flows by optimal control and differential games

AbstractGaining insights into pedestrian flow operations and assessment tools for pedestrian walking speeds and comfort is important in, for instance, planning and geometric design of infrastructural facilities, as well as for management of pedestrian flows under regular and safety‐critical circumstances. Pedestrian flow operations are complex, and vehicular flow simulation modelling approaches are generally not applicable to pedestrian flow modelling. This article focusses on pedestrian walking behaviour theory and modelling. It is assumed that pedestrians are autonomous predictive controllers that minimize the subjective predicted cost of walking. Pedestrians predict the behaviour of other pedestrians based on their observations of the current state as well as predictions of the future state, given the assumed walking strategy of other pedestrians in their direct neighbourhood. As such, walking can be represented by a (non‐co‐operative or co‐operative) differential game, where pedestrians may or may not be aware of the walking strategy of the other pedestrians. Copyright © 2003 John Wiley & Sons, Ltd.

The value of ultrasound after shoulder arthroplasty

This study was undertaken to evaluate whether sonography is a useful tool in the diagnosis of soft tissue disorders as a possible cause for discomfort and/or pain after shoulder arthroplasty. Static and dynamic ultrasound examinations were performed in the standard sectional planes on 22 patients with 25 hemiprostheses and the results were correlated with the clinical outcome. The stability was determined in the transverse and frontal planes and the clinical results were evaluated according to the Constant and Swanson scores. Several pathological changes were detected: rotator cuff lesions, subdeltoid bursitis, changes around the long biceps tendon as well as an increase in intra-articular volume due to effusion and/or synovitis. The correlation of sonographic and clinical results demonstrated that patients with an excellent clinical result showed no or only a few pathological findings on sonography compared with those with a moderate or poor result. Pathological changes of the periarticular tissue in the direct neighbourhood of the implant can be detected by sonography, which can be recommended as a valuable examination technique to evaluate the soft tissue in patients after shoulder arthroplasty.

Constraints on the S wave velocity structure in a continental shield from surface wave data: Comparing linearized least squares inversion and the direct search Neighbourhood Algorithm

In their study of upper mantle structure beneath the Paraná Basin of SE Brazil, Snoke and James [1997] concluded, on the basis of a linearized least squares inversion (LLSI) of surface wave dispersion data, that a strong (5% contrast) low‐velocity zone (LVZ) beginning at a depth less than ∼150 km was not required to fit the data. They were unable to establish a quantitative estimate, however, on the maximum depth at which such a LVZ could be resolved by their data. Sambridge [1999a, 1999b] has introduced the Neighbourhood Algorithm (NA), a direct search method for nonlinear inversion which can be tuned to extract information from an ensemble of models in addition to finding a single best fit model. Applying NA to the Brazilian dispersion data quantifies the statistics of the ensemble of models classified as “acceptable” based on a data misfit criterion and a smoothness constraint. The NA best fit model is not significantly different from the LLSI best fit model, but the analysis of the ensemble of models provides new insights regarding how well constrained the model is. Synthetics runs show that for this data set, our modeling procedures could resolve a strong LVZ that began at a depth of 120 km but could not rule out such an LVZ beginning at a depth of 180 km.

The effect of Ca and Thsubstitution on the crystal-field spectrum of the high-Tcsuperconductor HoBa2Cu3Ox

The inelastic neutron scattering technique was employed to study thetransitions between the low-lying levels of the ground-stateJ-multiplet of the Ho3+ ions inHo1-yCayBa2Cu3Ox (x≈6.3, 7.0; y≈0.1,0.2) and Ho1-yThyBa2Cu3Ox (x≈6.3;y≈0.07, 0.13) split by the crystalline electric field.For oxygen-rich Ca-doped samples, the observed energy spectraexhibit a fine structure, which reflects the behaviour of the localhole density near the doping centre. For the first time thisexperimental observation unambiguously confirms that the chargeinhomogeneity, which was found to be a characteristic feature of theunderdoped cuprates, still exists in the deeply overdoped regimewith Tc = 56 K. On the other hand, the modification of thecrystal-field spectra observed for the oxygen-deficient samples withboth Ca2+ and Th4+ substitutions for Ho3+ is foundto result from distortions of the copper-oxygen polyhedron aroundthe Ho3+ ion in the direct neighbourhood of the implantedions, rather than from the doping-induced variation of the carrierconcentration in the CuO2 planes.

Combination of microplate and miniplate for osteosynthesis of mandibular fractures: an experimental study

Because of the limited space available in the mandible, especially in the mental foramen and apical region, miniature osteosynthesis material is desirable. Recently, metal deposition in the direct neighbourhood of osteosynthesis plates made of titanium or even in peripheral organs have been reported in the literature with increasing frequency. The size and amount of osteosynthesis material used should therefore be kept to a minimum. In an experimental study on 60 models, we examined load-carrying stability and in a second series, torsional strength of two-piece plastic models connected by either a single miniplate, two miniplates, or a titanium microplate plus a miniplate. In our test arrangement, the average loading capacity of the combination miniplate/miniplate was 470N; that of the combination microplate/miniplate was only 267N. The test group with the single miniplate had an average loading capacity of only 225N. Masticatory loads on the plates exceeding 200N occur only 3 months after osteosynthesis. At that time the fracture has largely consolidated. The torsional strength of the microplate/miniplate combination was similar to that of the miniplate/miniplate combination (1000Nmm resulting in a width of the gap measuring 0.8mm and 0.5mm, respectively). The single miniplate was considerably less stable (0.8mm gap width as early as with 300Nmm). According to Champy, rotational forces in the anterior region of the mandible amount to approximately 1000Nmm and need to be withstood by the osteosynthesis material. Our results suggest that treatment of fractures in the interforaminal region with a combination of microplate and miniplate will be stable enough for early mobilization.

BRIDGED CYCLIC OLIGORIBONUCLEOTIDES—TOWARDS MODELS FOR CODON-ANTICODON PAIRING

Only three base pairs make up for stable double helices of regular A-type if both helix ends are bridged by flexible non-nucleotide linkers. These cyclic oligoribonucleotides are used as model systems for codon-anticodon pairing in order to reveal base stacking effects arising from structurally relevant bases in the direct neighbourhood of the core triplet duplex.

Cloning, expression, and characterization of acetate kinase from Lactobacillus sanfranciscensis

In the metabolism of Lactobacillus sanfranciscensis, the acetate kinase (AK) is a key enzyme and responsible for dephosphorylation of acetyl phosphate with the concomitant production of acetate and ATP. The L. sanfranciscensis ack gene was identified by PCR methods. It encodes a 397 amino acid protein sharing 56% similarity with Bacillus subtilis AK. Whereas cotranscription of ack and pta (phosphotransacetylase) is reported in previously characterised organisms, the L. sanfranciscensis ack gene is not located in direct neighbourhood to the encoding gene. AK was heterologously expressed in E. coli and characterised by its v(max) and Km values and by the dependence of enzyme activity on temperature and pH. Based on this data the in vivo role of the enzyme is discussed.

Low-energy vibrations in Sc 2@C 84 and Tm@C 82 metallofullerenes with different carbon cages

Raman scattering and infrared absorption is reported for various empty and filled fullerene isomers in the low-energy range below 600 cm −1 to clarify the influence of different carbon cage structures on the bonding strength between encapsulated metal ion and fullerene cage and to check the potential of vibrational spectroscopy for isomer identification. The spectra of three isomers of Tm@C 82 and three isomers of Sc 2@C 84 were measured at room temperature. The results are compared to the response of the most abundant isomers of empty C 84 as well as to data for C 82 and C 60. The vibrational structure of the higher empty fullerene cages C 82 and C 84 resembles a downshifted and split C 60 spectrum. Moreover the spectra of the two C 84 isomers exhibited only small differences due to the very similar molecular structure, i.e. identical hexagon indices and direct neighbourhood in the Stone–Wales conversion map. Larger differences of the low-energy cage modes were found for the Tm@C 82 isomers and in particular for the Sc 2@C 84 isomers. This goes along with an increasing difference in hexagon indices and a larger distance on the Stone–Wales conversion map. Due to the charge transfer from the endohedral metal to the fullerene the low-energy cage modes are shifted in the same direction as the modes of C 60 during the exohedral doping process with alkali metals. New lines induced by the endohedral scandium and thulium ions with almost complementary Raman and infrared intensities were found for Sc 2@C 84 below 200, around 250 and 260 cm −1 and for Tm@C 82 at 116 to 118 cm −1 and at 42 cm −1. These vibrations were further identified as M–C 2 n stretching and M–C 2 n deformation modes. Only a minor influence of the cage isomerism on these modes was observed. This is consistent with a simple ionic picture for the interaction between carbon cage and encapsulated metal ion. It is the amount of metal to fullerene charge transfer and the distance of the oppositely charge centres which determine the carbon cage–metal ion bond strength.

Stem water potential and leaf conductance: A comparison of sorbus aucuparia and Sambucus nigra

Sorbus aucuparia is a pioneer wood which can naturally be found on extreme habitats, e.g. rocky slopes and mountain forests. Sambucus nigra is a species of flood-plain forests. The different strategies of survival of these two species were studied on planted shrubs which were exposed to the same microclimatic conditions in the outdoors of the Botanical Garden of Diisseldorf University. This situation - both species in direct neighbourhood - also exists where Sorbus aucuparia and Sambucus nigra are brought together by man in common habitats like hegerows.Measurements of stem water potential and leaf conductance were carried out on these planted shrubs during the growing season of 1995 under natural conditions. A hot dry period caused a decrease of stem water potential of Sorbus aucuparia below −4 MPa, while Sambucus nigra merely reached a minimum of −1.64 MPa. Sambucus had a lower maximum of leaf conductance than Sorbus and avoided a decrease of stem water potential by reducing leaf conductances early after the beginning of drought. By contrast Sorbus aucuparia showed high leaf conductance,; during one month of drought until water potentials of the shrub had been fallen below −4 MPa. These contrasting patterns of seasonal variations of water potential and stomatal control of transpiration confirm the classification of Sorbus aucuparia as a hydrolabile and Sambucus nigra as a hydrostabile species.

98/03416 Biological processing of coal and carbonaceous material: Catcheside, D. E. A. and Ralph, J. P. DGMK Tagungsber., 1997, 9702 (Proceedings ICCS '97, Volume 1), 11–18

The participation of extracellular oxidative enzymes, as known from lignin degraders, in fungal coal degradation is demonstrated and discussed in this paper. Two basidiomycete strains that are able to solubilize German lignite (brown coal) were isolated and characterized according to their enzymology. One of them (strain RBS 1k) produces extracellular Mn-peroxidase, the other (strain RBS 1b) excretes two oxidative enzymes with laccase and peroxidase activity. These enzymes were excreted shortly before the beginning of coal solubilization. Different coal substances can affect the production of these exoenzymes. The production of extracellular peroxidase by strain RBS 1k can be induced by the addition of native lignite powder or different lignite fractions (bitumen, matrix and humic acids) to the culture medium. Fungal growth was enhanced under these culture conditions, too. On the other hand, production of extracellular laccase activity by strain RBS 1b can be stimulated by the addition of water-soluble humic acids, too, but is inhibited by the addition of other coal fractions (bitumen and matrix) or by native lignite powder. In the direct neighbourhood of lignite pieces the fungal surface cultures of the basidiomycete RBS 1k show guttation. The drops are dark brown colored and contain strong peroxidase activity (up to 300 U/ml). But this cellfree solution is not able to solubilize coal, alone. The fungus RBS 1k possesses enzymatic capacities for modifying the structure of coal-derived humic acids. The strain can metabolize these alkali-soluble coal macromolecules under cometabolic conditions by simultaneous excretion of peroxidase, which probably is involved in the degradation process. In vitro-tests with the cellfree peroxidase (RBS 1k) or laccase (RBS 1b), purified by affinity chromatography, could not demonstrate the ability of these enzymes to promote water solubility of low rank coals, alone.

Risk of damage to crops in the direct neighbourhood of ammonia sources

In the Netherlands ammonia is emitted from several thousand sources (animal buildings, manured pastures, slurry storage facilities, etc.). Obviously, the ammonia concentrations are higher close to the source, but at this short distance vegetation has no special value in terms of nature conservation, as it mostly consists of ammonia-resistant agricultural crops. However, three crop categories include relatively sensitive species (fruity culture, glasshouse crops and arboriculture). This paper presents an estimation of the risk of ammonia damage to sensitive crops as related to the distance to the source, based on the mean and variation in emission, dispersion, regional background concentration, landscape characteristics and plant sensitivity. Some attention is paid to damage of natural vegetation and to risk-reducing measures (elevation of emission point, wind fence around the source). The goal is to provide information for regional and local officials and farmers who are dealing with risk evaluation, claims for damages, and environmental policy matters like stable reallocations etc.

Mapping of members of the low-copy-number repetitive DNA sequence family chAB4 within the p arms of human acrocentric chromosomes: characterization of Robertsonian translocations.

Members of the long-range, low-copy-number repetitive DNA sequence family chAB4 are located on nine different human chromosome pairs and the Y chromosome, i.e. on the short arms of all the acrocentrics. To localize the chAB4 sequences more precisely on the acrocentrics, chAB4-specific probes together with rDNA and a number of satellite sequences were hybridized to metaphase chromosomes of normal probands and of carriers of Robertsonian translocations of the frequent types rob(13q14q) and rob(14q21q). The results demonstrate that chAB4 is located on both sides of the rDNA on all the acrocentrics; the exact location, however, may be chromosome specific. Chromosome 22, most probably, is the only chromosome where chAB4 is found in the direct neighbourhood of the centromere. Fluorescence in situ hybridization analyses of metaphase chromosomes of carriers of rob(21q22q) revealed breakpoint diversity for this rare type of Robertsonian translocation chromosome. A direct involvement of chAB4 sequences in recombination processes leading to the Robertsonian translocations analysed in this study can be excluded.

Extracellular oxidative enzymes of coal-attacking fungi

The participation of extracellular oxidative enzymes, as known from lignin degraders, in fungal coal degradation is demonstrated and discussed in this paper. Two basidiomycete strains that are able to solubilize German lignite (brown coal) were isolated and characterized according to their enzymology. One of them (strain RBS 1k) produces extracellular Mn-peroxidase, the other (strain RBS 1b) excretes two oxidative enzymes with laccase and peroxidase activity. These enzymes were excreted shortly before the beginning of coal solubilization. Different coal substances can affect the production of these exoenzymes. The production of extracellular peroxidase by strain RBS 1k can be induced by the addition of native lignite powder or different lignite fractions (bitumen, matrix and humic acids) to the culture medium. Fungal growth was enhanced under these culture conditions, too. On the other hand, production of extracellular laccase activity by strain RBS 1b can be stimulated by the addition of water-soluble humic acids, too, but is inhibited by the addition of other coal fractions (bitumen and matrix) or by native lignite powder. In the direct neighbourhood of lignite pieces the fungal surface cultures of the basidiomycete RBS 1k show guttation. The drops are dark brown colored and contain strong peroxidase activity (up to 300 U/ml). But this cellfree solution is not able to solubilize coal, alone. The fungus RBS 1k possesses enzymatic capacities for modifying the structure of coal-derived humic acids. The strain can metabolize these alkali-soluble coal macromolecules under cometabolic conditions by simultaneous excretion of peroxidase, which probably is involved in the degradation process. In vitro-tests with the cellfree peroxidase (RBS 1k) or laccase (RBS 1b), purified by affinity chromatography, could not demonstrate the ability of these enzymes to promote water solubility of low rank coals, alone.

Contribution de la biomicroscopie ultrasonore au traitement conservateur des mélanomes de l'uvŽe antérieure

Ultrasound Biomicroscopy (UBM) is a new ophthalmological imaging technique essentially designed for the study of the anterior eye segment. Over the last 10 months, we've evaluated its contribution to the conservative treatment of anterior uveal melanoma's by means of accelerated proton beam irradiation. Using UBM, we have examined 55 cases of uveal melanoma's, whose anterior border was situated at 6 mm or less from the limbus and that were consequently treated by proton beam irradiation. The presumed tumoral origin was the ciliary body's pars plicata in 13 cases and the pars plana or the choroid in 42 cases, 17 of which presented a tumoral invasion of the pars plicata. A pars plana detachment anterior to or surrounding the anterior tumoral border, was present in 22 cases. The height of the tumor could only be measured by UBM if it was less than 2.5 mm. Information gathered using UBM have contributed to an improvement of the therapy plan in 32 cases. Because of the strong attenuation of the high frequency ultrasound signal, UBM can only be used for the examination of intra-ocular structures situated in direct neighbourhood to the global wall. Despite this technical limitation, ist contribution to the planning of the conservative treatment of anterior uveal melanoma's by proton beam irradiation has appeared to be considerable.

1383 Cytostatics information programme

The administration of cytostatics is increasingly moving from clinics towards outpatients departments. As a result of this development, family doctors and home nurses have to deal with the side-effects of the chemotherapy. Due to the small number of patients per family doctor, it did not seem useful to organize educational programmes on cytostatics for the family doctors. Communication between the treater and the medical assistance in the direct neighbourhood of the patient becomes of considerable importance. Our project is focussed on the communication problems between hospital and family doctor, which are based on insufficient exchange of information. On 40 of the most commonly used cytostatics, information leaflets were designed, in which action, side-effects and interaction are recorded. On the back of each card advice is given on how to deal with the most common side effects; a telephone number is added in case there are any questions. At the start of the cytostatic therapy the nurse in the outpatients department sends the information leaflets, which are patient-bound, to the family doctor. For the patients a cytostatics-passport was designed, in which the name and the main side-effects that require medical assistance of the chemotherapy-scheme is given. After evaluation the cytostatics information programme was implemented in all the outpatients departments (10) in our region (1.2 million inhabitants). The programme was also offered to the other comprehensive cancer centres. It is now being used in almost 35 hospitals throughout the country. The administration of cytostatics is increasingly moving from clinics towards outpatients departments. As a result of this development, family doctors and home nurses have to deal with the side-effects of the chemotherapy. Due to the small number of patients per family doctor, it did not seem useful to organize educational programmes on cytostatics for the family doctors. Communication between the treater and the medical assistance in the direct neighbourhood of the patient becomes of considerable importance. Our project is focussed on the communication problems between hospital and family doctor, which are based on insufficient exchange of information. On 40 of the most commonly used cytostatics, information leaflets were designed, in which action, side-effects and interaction are recorded. On the back of each card advice is given on how to deal with the most common side effects; a telephone number is added in case there are any questions. At the start of the cytostatic therapy the nurse in the outpatients department sends the information leaflets, which are patient-bound, to the family doctor. For the patients a cytostatics-passport was designed, in which the name and the main side-effects that require medical assistance of the chemotherapy-scheme is given. After evaluation the cytostatics information programme was implemented in all the outpatients departments (10) in our region (1.2 million inhabitants). The programme was also offered to the other comprehensive cancer centres. It is now being used in almost 35 hospitals throughout the country.

Feeding patterns of the larch casebearer Coleophora laricella Hbn. (Lep., Coleophoridae) on European larch

AbstractFeeding patterns of the larch casebearer Coleophora laricella Hbn. were investigated for eggs, 2nd/3rd instars, 4th instars and pupae in a 21‐year‐old larch stand. No significant differences occurred between the infestation rates of border‐ and within‐stand‐trees; no preferences were found for cardinal points. Clear preferences were detected for distal twig sections. There seems to be a tendency to higher densities in the middle parts of larch crowns. Larch trees in the direct neighbourhood of beech showed significantly lower moth densities than larch in pure stands. This may be a result of different physiological interactions between moth and host tree in pure or mixed stands, respectively.

Nieznane bagienne miejsce ofiarne z okresu rzymskiego na terenie Wielkopolski

Nieznane bagienne miejsce ofiarne z okresu rzymskiego na terenie Wielkopolski