Compression control and its significance in the manufacture and effects on properties of poplar LVL

Summary In order to control the compression effectively, the main processing parameters for hot-pressing of poplar LVL were investigated in this study. Results from an orthogonal experiment show qualitatively that compression of poplar LVL is influenced by pressing pressure and moisture content of the veneers. High press pressure and veneer moisture content lead to high compression during hot pressing. It is shown that compression has significant effects on modulus of elasticity, modulus of rupture, specific gravity and thickness swelling of poplar LVL. Modulus of elasticity, modulus of rupture and specific gravity appear to be directly proportional to compression within the compression range of 5% to 20%. Horizontal shear strength results indicate that, due to inadequate contact, proper glue bond may not be achieved between veneers of LVL with low compression. Thickness swelling appears not sensitive to compression between the compression range of 4% to 10%.The authors wish to acknowledge the financial support from the Natural Sciences and Engineering Research Council of Canada to this study, which was carried out when the first author was a visiting scientist at Wood Science and Technology Centre, University of New Brunswick, Canada. The veneers and adhesive used in this study were provided by Temlam Inc., Ville-Marie, Quebec. Their contribution is gratefully acknowledged.     

Tollwut bei Fledermäusen

Ohne Zusammenfassung     

Vorkommen und Haltung der ?stlichen Honigbiene (Apis cerana Fabr.) in Afghanistan

Ohne Zusammenfassung     

A type II-collagen derived peptide and its nitrated form as new markers of inflammation and cartilage degradation in equine osteochondral lesions

Markers of cartilage breakdown enable studying the degradation of cartilage matrix in equine joint pathologies. This study was designed to determine the levels of Coll2-1, a peptide of the triple helix of type II collagen, and Coll2-1NO(2), its nitrated form in the plasma of healthy horses (controls; n=37) and horses suffering from osteochondrosis (n=34). Clinical and arthroscopic scores were attributed reflecting the severity of lesions and were related to the plasma levels of Coll2-1 and Coll2-1NO(2). The median of Coll2-1 was significantly higher in the control group, whereas the mean of Coll2-1NO(2) showed significant elevation in the pathological group. However, the measurement means of scoring classes did not vary significantly. The markers were able to differentiate the group of horses suffering from osteochondrosis from the group of healthy horses. The elevation of Coll2-1NO(2) in the pathological group indicates an inflammation, mediated through reactive oxygen species and/or increased myeloperoxidase activity.     

Hazard Analysis and Critical Control Points System for a Bull Semen Production Centre

Bull semen production centres (SPC) generally present satisfactory quality control for sperm processing, but non‐standardized hygiene procedures. This study describes a Hazard Analysis and Critical Control Points (HACCP) system developed for bull SPC and subsequently implemented in a commercial SPC. After the identification of hazards at each step of semen processing and the determination of their risk and severity, monitoring and corrective procedures were designed to assess the system's efficiency. The HACCP system identified six microbiological hazards, 10 physical hazards, four chemical hazards and three critical control points. After the establishment of Good Processing Practices, Standard Operating Procedures and Standard Sanitizing Operating Procedures, the system was validated through an audit, to identify eventual failures and to define measures to correct them.     

Regional Differences in the Relation Between Monthly Precipitation and Bulk Concentration in France (Renecofor)

Bulk precipitation was sampled weekly from 1993 to 1994 at 27 sites, covering the whole country. In this paper the relations between decreasing concentrations of 4-weekly mean weighted samples with increasing 4-weekly precipitation are studied using two types of equations: (i) y = a+b/x; (ii) y+1= ax^b, where y = concentration of an ion and x = 4-weekly precipitation quantity. Relationships were studied for the major ions. H⁺ did not show any relationship with the rainfall amount. From the 216 regressions (27 sites × 8 ions) for all the other ions, 55.6% showed a good fit (r equal or above 0.6) and 16.2% a very good fit (r equal or above 0.85). Good fits were found for 85% of the regressions for N-NO₃ ^-, 81% for S-SO₄ ^2-, 63% for Ca²⁺, 59% for K⁺, 55% for N-NH₄ ⁺, 37% for Mg²⁺, 33% for Cl^- and 29% for Na⁺. The comparison between sites for the same ions showed: (i) the ranking of the sites after the regressions from lower to higher concentration levels does not necessarily correspond to the ranking of the sites bi-annual mean weighted concentrations; (ii) sites showed similar behaviour for certain ions for which an explanation could be found, based on local or regional emission characteristics or air mass influences, and for others this was not possible; (iii) for certain ions and pairs of sites, comparable annual precipitation led to comparable behaviour, for others precipitation was not an explanatory factor at all, (iv) local and regional influences seem to have a much greater impact on decreasing concentrations than the gradient from the Atlantic coast to the eastern French border.     

Antigenic characterization of street rabies virus isolates from Nigeria using monoclonal antibodies

Twenty isolates of street rabies virus were recovered in mouse neutroblastoma cells from 84 rabies suspect brain specimens from Nigeria dogs and a cat. They were characterized with the Tübingen monoclonal antibody panels directed against nucleocapsid and glycoprotein antigens. Antigenic variations were detected both with antinucleocapsid (anti-NC) and antiglycoprotein (anti-GP) monoclonal antibodies (mabs). One isolate reacted positively with anti-NC mab P41 which hitherto has been known to react positively with polar rabies. Another isolate did not react with anti-NC mab 187.5; a reaction normally seen with ERA/SAD strains of rabies virus. With anti-GP mabs it was possible to group the isolates by their area of origin. Isolates from Plateau State were not neutralized by anti-GP mabs ERA 543 and P44.7.2. The isolates studied had glycoprotein antigenic patterns different from the pattern for low egg passage (LEP) Flury strain vaccine virus used in Nigeria for immunization of dogs.     

Platelet affinity for burro aorta collagen.

Despite ingenious concepts, there are no unequivocal clues as to what, when, and how some undefined biochemical factor(s) or constituent(s) that localizes in the arterial wall can precipitate a thromboatheromatous lesion or arterial disease. The present study focused on the extraction, partial purification, and characterization of a collagen-active platelet stimulator from the aortas of aged burros. The aggregator moiety in the aorta extracts invariably had a higher affinity for platelets in citrated platelet-rich plasma of human beings than for platelets of homologous burros. The platelet-aggregating factor(s) in the aorta extract was retained by incubation with alpha-chymotrypsin. Platelet-aggregating activity was rapidldy abolished after incubation with collagenase, as determined by plateletaggregometry tests. Evidence based on light microscope and polysaccharide histochemical reactions indicates a probability that the intracellular amorphous matrix (PAS-positive) and filamentous components (PTAH-positive) expelled from smooth muscle cells disrupted during homogenization of the aorta may be a principle source of a precursor collagen species which is a potent inducer of platelet aggregation.