102 research outputs found
Genetic Variation of Juvenile Wood Properties in a Loblolly Pine Diallel Test
The reduced rotation age for loblolly pine plantations has resulted in an increased percentage of juvenile wood. Juvenile wood has lower wood density, shorter tracheid length and higher lignin content than mature wood. The increased use of juvenile wood has reduced yields and increased pulping costs for the pulp and paper industry. If significant genetic variation in juvenile wood properties can be found, breeders may be able to improve juvenile wood properties to reduce pulping losses. Genetic variation in several wood quality traits of loblolly pine (Pinus taeda L.) was investigated for 14 full-sib families generated by a 6-parent half-diallel mating design. Wood samples of 12 mm increment cores were collected from 11-year-old trees from one test site. Earlywood and latewood of ring three (juvenile wood) and ring eight (transition wood) for each increment core were analyzed for alpha cellulose content (ACY), average fiber length (FLW), coarseness (COA), and lignin content (LIG). Ring three and ring eight had significant differences in ACY, FLW, and COA, but not for LIG. Latewood of both rings had higher ACY, FLW, and COA than earlywood. Transition wood had significantly higher ACY, FLW, and COA, but lower LIG than juvenile wood. Families differed significantly for ACY, FLW, and COA, but not for LIG. In general, additive genetic effects explained greater percentages of family variation than dominance genetic effects. Genetic variation increased from juvenile to transition wood. While weak individual and family heritabilities were found for ACY, FLW, and COA for juvenile wood, heritability estimates for transition wood were moderate, indicating the potential for improving these juvenile traits.Papers and abstracts from the 27th Southern Forest Tree Improvement Conference held at Oklahoma State University in Stillwater, Oklahoma on June 24-27, 2003
Helicobacter Pylori Infection in Endoscopic Biopsy Specimens of Gastric Cancer: A Preliminary Evaluation in a High Risk Population of Kashmir Valley
Objective: The aim of the present study was to assess the prevalence of Helicobacter
pylori (H. pylori) infection in Kashmiri patients with gastric cancer and to compare this
with a matched control population
Variable Stars in Galactic Globular Clusters
Based on a search of the literature up to May 2001, the number of known
variable stars in Galactic globular clusters is approximately 3000. Of these,
more than 2200 have known periods and the majority (approximately 1800) are of
the RR Lyrae type. In addition to the RR Lyrae population, there are
approximately 100 eclipsing binaries, 120 SX Phe variables, 60 Cepheids
(including population II Cepheids, anomalous Cepheids and RV Tauri) and 120
SR/red variables. The mean period of the fundamental mode RR Lyrae variables is
0.585, for the overtone variables it is 0.342 (0.349 for the first-overtone
pulsators and 0.296 for the second-overtone pulsators) and approximately 30%
are overtone pulsators. These numbers indicate that about 65% of RR Lyrae
variables in Galactic globular clusters belong to Oosterhoff type I systems.
The mean period of the RR Lyrae variables in the Oosterhoff type I clusters
seems to be correlated with metal abundance in the sense that the periods are
longer in the more metal poor clusters. Such a correlation does not exist for
the Oosterhoff type II clusters. Most of the Cepheids are in clusters with blue
horizontal branches.Comment: 45 pages, 10 figures, to be published in AJ November 200
Pulping and bleaching of partially CAD-deficient wood
"May 2002."Submitted to Journal of Wood Chemistry and Technology
Bimodality and Gaps on Globular Cluster Horizontal Branches. II. The Cases of NGC 6229, NGC 1851 and NGC 2808
The outer-halo globular cluster NGC 6229 has a peculiar horizontal-branch
(HB) morphology, with clear indications of a bimodal HB and a ``gap" on the
blue HB. In this paper, we present extensive synthetic HB simulations to
determine whether peculiar distributions in the underlying physical parameters
are needed to explain the observed HB morphology. We find that a unimodal mass
distribution along the HB can satisfactorily account for the observed HB
bimodality, *provided* the mass dispersion is substantially larger than usually
inferred for the Galactic globular clusters. In this case, NGC 6229 should have
a well-populated, extended blue tail. A truly bimodal distribution in HB masses
can also satisfactorily account for the observed HB morphology, although in
this case the existence of an extended blue tail is not necessarily implied.
The other two well-known bimodal-HB clusters, NGC 1851 and NGC 2808, are
briefly analyzed. While the HB morphology of NGC 1851 can also be reproduced
with a unimodal mass distribution assuming a large mass dispersion, the same is
not true of NGC 2808, for which a bimodal, and possibly multimodal, mass
distribution seems definitely required.
The problem of gaps on the blue HB is also discussed. Applying the standard
Hawarden (1971) and Newell (1973) chi-squared test, we find that the NGC 6229
gap is significant at the 99.7% level. However, in a set of 1,000 simulations,
blue-HB gaps comparable to the observed one are present in ~ 6 - 9% of all
cases. We employ a new and simple formalism, based on the binomial
distribution, to explain the origin of this discrepancy, and conclude that
Hawarden's method, in general, substantially overestimates the statistical
significance of gaps.Comment: 50 pages (includes 5 tables and 18 multi-panel figures).
Higher-resolution versions of Figs. 15a and 15b are available from the first
author upon request. To appear in The Astrophysical Journa
Anti-HIV-1 activity of anionic polymers: a comparative study of candidate microbicides
BACKGROUND: Cellulose acetate phthalate (CAP) in soluble form blocks coreceptor binding sites on the virus envelope glycoprotein gp120 and elicits gp41 six-helix bundle formation, processes involved in virus inactivation. CAP is not soluble at pH < 5.5, normal for microbicide target sites. Therefore, the interaction between insoluble micronized CAP and HIV-1 was studied. Carbomer 974P/BufferGel; carrageenan; cellulose sulfate; dextran/dextrin sulfate, poly(napthalene sulfonate) and poly(styrene-4-sulfonate) are also being considered as anti-HIV-1 microbicides, and their antiviral properties were compared with those of CAP. METHODS: Enzyme linked immunosorbent assays (ELISA) were used to (1) study HIV-1 IIIB and BaL binding to micronized CAP; (2) detect virus disintegration; and (3) measure gp41 six-helix bundle formation. Cells containing integrated HIV-1 LTR linked to the β-gal gene and expressing CD4 and coreceptors CXCR4 or CCR5 were used to measure virus infectivity. RESULTS: 1) HIV-1 IIIB and BaL, respectively, effectively bound to micronized CAP. 2) The interaction between HIV-1 and micronized CAP led to: (a) gp41 six-helix bundle formation; (b) virus disintegration and shedding of envelope glycoproteins; and (c) rapid loss of infectivity. Polymers other than CAP, except Carbomer 974P, elicited gp41 six-helix bundle formation in HIV-1 IIIB but only poly(napthalene sulfonate), in addition to CAP, had this effect on HIV-1 BaL. These polymers differed with respect to their virucidal activities, the differences being more pronounced for HIV-1 BaL. CONCLUSIONS: Micronized CAP is the only candidate topical microbicide with the capacity to remove rapidly by adsorption from physiological fluids HIV-1 of both the X4 and R5 biotypes and is likely to prevent virus contact with target cells. The interaction between micronized CAP and HIV-1 leads to rapid virus inactivation. Among other anionic polymers, cellulose sulfate, BufferGel and aryl sulfonates appear most effective in this respect
Pretreatment of Japanese cedar by ionic liquid solutions in combination with acid and metal ion and its application to high solid loading
Electrospun green fibres from lignin and chitosan: a novel polycomplexation process for the production of lignin-based fibres
Reactions of Lignin with Cyanamide Activated Hydrogen Peroxide. Part 3. The Degradation of Pine Kraft Lignin
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