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PubMedDate not supplied

Temperature stress tolerance of conifer seedlings after exposure to UV-B radiation.

Ground-level UV-B radiation has increased globally due to a thinning stratospheric ozone layer. We estimated the effects of increased UV-B on 10 conifer species grown in chambers in greenhouses with supplemental UV-B. Species were selected from a wide range of geographic locations. Plant material of two ages (germinants, first growing season; seedlings, second season) were exposed to three levels of UV-B from ambient (at Victoria, B.C., Canada) to three times ambient (12 kJ m(-2) d(-1)) for up to four months. Frost hardiness and heat tolerance of shoots were estimated from changes in chlorophyll fluorescence after exposure to test temperatures. There were no significant differences among seed sources from different elevations in their response to temperature stresses. When UV-B increased above the ambient level, three species (interior Douglas-fir, Engelmann spruce, and interior lodgepole pine) increased in frost hardiness and four (grand fir, interior spruce, yellow-cedar, and western redcedar) decreased. Two species (western redcedar and western hemlock) increased in heat tolerance when UV-B increased to the 12 kJ level. The main differences in stress tolerance were between the triple ambient and the other two treatments, not between ambient and double ambient, suggesting that any changes in UV-B would have to be large to elicit physiological changes in conifer seedlings.

Freezing↗
PubMed2006

Comparative potential of Aedes triseriatus, Aedes albopictus, and Aedes aegypti (Diptera: Culicidae) to transovarially transmit La Crosse virus.

Aedes triseriatus (Say) (Diptera: Culicidae), the major vector of La Crosse (LAC) virus, efficiently transmits LAC virus both horizontally and transovarially. We compared the vector competence and transovarial transmission ability of Ae. triseriatus, Aedes albopictus Skuse, and Aedes aegypti (L.) for LAC virus. Ae. triseriatus and Ae. albopictus were significantly more susceptible to oral infection with LAC virus than Ae. aegypti. The three species also differed in oral and disseminated infection rates (DIRs). Transovarial transmission (TOT) rates and filial infection rates (FIRs) were greater for Ae. triseriatus than either Ae. albopictus or Ae. aegypti. These measures were integrated into a single numerical score, the transmission amplification potential (TAP) for each species. Differences in TAP scores were due mainly to the differences in DIRs and FIRs among these mosquitoes. Although the TAP score for Ae. albopictus was lower than that of Ae. triseriatus, it was 10-fold greater than that for Ae. aegypti.

Aedes↗
PubMed2006

Demography of northern flying squirrels informs ecosystem management of western interior forests.

We studied northern flying squirrel (Glaucomys sabrinus) demography in the eastern Washington Cascade Range to test hypotheses about regional and local abundance patterns and to inform managers of the possible effects of fire and fuels management on flying squirrels. We quantified habitat characteristics and squirrel density, population trends, and demography in three typical forest cover types over a four-year period. We had 2034 captures of flying squirrels over 41 000 trap nights from 1997 through 2000 and marked 879 squirrels for mark-recapture population analysis. Ponderosa pine (Pinus ponderosa) forest appeared to be poorer habitat for flying squirrels than young or mature mixed-conifer forest. About 35% fewer individuals were captured in open pine forest than in dry mixed-conifer Douglas-fir (Pseudotsuga menziesii) and grand fir (Abies grandis) forests. Home ranges were 85% larger in pine forest (4.6 ha) than in mixed-conifer forests (2.5 ha). Similarly, population density (Huggins estimator) in ponderosa pine forest was half (1.1 squirrels/ha) that of mixed-conifer forest (2.2 squirrels/ha). Tree canopy cover was the single best correlate of squirrel density (r = 0.77), with an apparent threshold of 55% canopy cover separating stands with low- from high-density populations. Pradel estimates of annual recruitment were lower in open pine (0.28) than in young (0.35) and mature (0.37) forest. High recruitment was most strongly associated with high understory plant species richness and truffle biomass. Annual survival rates ranged from 45% to 59% and did not vary among cover types. Survival was most strongly associated with understory species richness and forage lichen biomass. Maximum snow depth had a strong negative effect on survival. Rate of per capita increase showed a density-dependent response. Thinning and prescribed burning in ponderosa pine and dry mixed conifer forests to restore stable fire regimes and forest structure might reduce flying squirrel densities at stand levels by reducing forest canopy, woody debris, and the diversity or biomass of understory plants, truffles, and lichens. Those impacts might be ameliorated by patchy harvesting and the retention of large trees, woody debris, and mistletoe brooms. Negative stand-level impacts would be traded for increased resistance and resilience of dry-forest landscapes to now-common, large-scale stand replacement fires.

Animals↗
PubMed1998

Evidence that far infrared radiation promotes growth of Xenopus laevis.

In most ectotherms, environmental temperature has differential effects on growth and differentiation. For example, amphibian size at maturity decreases with increasing temperature. To address how radiant heat in the form of far-infrared radiation (FIR) may affect development of the aquatic ectotherm Xenopus laevis, we continuously irradiated swimming larvae as they developed into young adults. Here we report evidence that FIR promotes growth of these organisms in an aqueous environment.

Animals↗
PubMed2003

Beta-cell capacity and insulin sensitivity in prepubertal children born small for gestational age: influence of body size during childhood.

Insulin secretion and sensitivity was studied in 28 prepubertal children born small for gestational age (SGA) and in 22 prepubertal children born appropriate for gestational age (AGA). The effect of body size during childhood was also assessed. Insulin sensitivity was measured using the hyperinsulinemic-euglycemic clamp (M value), and beta-cell function was studied with the hyperglycemic clamp plus arginine. First-phase insulin response (FIR) was used to calculate the disposition index (FIR x M value). Arginine-stimulated second-phase insulin response was used as a measure of beta-cell capacity. DeltaBMI(0-1 year), DeltaBMI(0-2 years), and DeltaBMI(2-9 years) were classified in tertiles. SGA children were less insulin sensitive than AGA children (P = 0.009). beta-Cell capacity and disposition indexes were similar in the two groups. In SGA children, M values were lower in the tertile with the highest DeltaBMI(2-9 years) than in the tertile with the lowest DeltaBMI(2-9 years) (P = 0.01). No association between DeltaBMI(0-2 years) and decreased insulin sensitivity was found. In conclusion, prepubertal SGA children show decreased insulin sensitivity rather than decreased beta-cell capacity. Interventions to improve fetal growth and prevent overweight after the second year of life appear to be important factors in the prevention of type 2 diabetes in children born SGA.

Aging↗
PubMed1994

[Acoustic analysis of certain consonants using a computed model of the peripheral auditory system].

Stop consonants [p], [t], [k] and a fricative [s] were acoustically analyzed using a computed model of the peripheral auditory system in 12 normal subjects and 12 patients with tumors of the tongue who had undergone surgical resection and reconstruction. The model is a combination of the cochlear model that consists of 28 FIR filters (Delgutte) and the inner hair-cell/auditory nerve synapse model (Meddis), with some modification. It simulates firing of the auditory nerve in every channel related to the FIR filters in response to an input voice signal. Phonetic characteristics of the tested consonants were more clearly visualized by observing firing patterns and voice onset time (VOT) using this auditory model than with use of the conventional soundspectrogram. In patients with tumors of the tongue, the degree of distorted articulation and the area of surgical resection were significantly related to obscurity of the phonetic characteristics of the stop consonants [t] and [k]. Acoustic analysis using this auditory model may serve as a useful tool for voice analysis in research and in the clinical field.

Computer Simulation↗
PubMed2004

Bamboo charcoal inhibits growth of HeLa cells in vitro.

The purpose of this work was to investigate the far infrared spectral characteristics of bamboo charcoal powder and its effect on cancer cells for use in the dental field. To analyze the effects of the powder, HeLa and WI-38 cells were used and then assessed by cell adhesion assay and WST-1 assay. The powder emitted far infrared rays at wavelengths between 4 to 16 microm. The multiplication rate of WI-38 cells showed no significant differences between the conventional culture (control group) and culture on the powder (FIR group). However, at six days after incubation, HeLa cells of FIR group had a significantly lower multiplication rate compared with the control group. Based on the far infrared rays emitted in this study, bamboo charcoal powder proved to be a promising dental filler material for cancer prevention.

Cell Adhesion↗
PubMed1983

Persistence of La Crosse virus (California encephalitis serogroup) in north-central Illinois.

La Crosse (LAC) virus was first isolated in Illinois from a pool of 50 female Aedes triseriatus mosquitoes collected in July 1976, in Peoria Heights. From 1978 through 1981, 27 strains (11 from males and 16 from females) of LAC virus were recovered from 888 pools containing 22,021 adult A. triseriatus mosquitoes from the same study area. These mosquitoes had developed from larvae and pupae collected from 50 individually identified treeholes. Of the 14 trees that yielded LAC virus-positive mosquitoes, one was positive in 3 of 4 years and another was positive in all 4 years. The latter tree had minimum mosquito field infection rates (MFIR) ranging from 3.4 to 12.7/1,000. Eight (57%) of the trees with positive mosquitoes were red oak (Quercus rubra) while 10 (71%) were in the oak genus (Quercus). The four most productive treeholes accounted for 30% of mosquitoes tested and 52% of the LAC isolations. In 1979, 6,729 A. triseriatus mosquitoes were collected in man-baits and tested for virus. From 1,282 tested in 259 pools (mean = 5), 13 LAC isolates were made, resulting in a field infection rate (FIR) of 11.4/1,000. The remaining 5,447 were tested in 218 pools (mean = 25) and 48 strains of LAC were isolated for a FIR of 9.9/1,000. The relationship of these findings to the occurrence of human LAC encephalitis cases in Peoria County, Illinois is discussed. Repeated recovery of virus from this study area reflects a stable, yet dynamic, focus of LAC virus transmission.

Aedes↗
PubMed2001

Exposure to airborne microorganisms in Polish sawmills.

Microbiological air sampling was performed in four sawmills located in eastern Poland, of which two were processing coniferous wood (pine, fir) and other two deciduous wood (oak, birch). Total concentration of microorganisms (bacteria and fungi) in the air of sawmills processing coniferous wood was on average 20.2 +/- 5.6 x 10(3) cfu/m(3) (mean +/- S.E.) and significantly (p < 0.05) higher compared to those processing deciduous wood where the mean concentration of airborne microorganisms was 9.8 +/- 3.0 x 10(3) cfu/m(3). The greatest concentrations of microorganisms in the sawmills processing coniferous wood were noted at debarking and at first-cut frame sawing of pine logs (42.1 +/- 7.6 x 10(3) cfu/m(3) and 39.8 +/- 7.0 x 10(3) cfu/m(3), respectively). Microflora released into air during debarking consisted mostly of allergenic fungi (mainly Aspergillus fumigatus) and corynebacteria, whereas airborne microflora recovered during first-cut frame sawing constituted mostly of endotoxin-producing Gram- negative bacteria of the genus Rahnella, developing in the sapwood of pine. In the sawmills processing deciduous wood, the largest concentration of microorganisms (30.6 +/- 3.4 x 10(3) cfu/m(3)) was found at sorting of the oak parquet boards and was due to the secondary infection of the boards with moulds Penicillium citrinum during prolonged storing in the open air. Values of the respirable fraction of airborne microflora in the examined sawmills varied within fairly wide limits and were between 22.5 86.6%. Altogether, 34 species or genera of bacteria and 21 species or genera of fungi were identified in the air of sawmills, of which respectively 13 and 9 species or genera were reported as having allergenic and/or immunotoxic properties. The concentrations of airborne bacterial endotoxin which were determined on two sampling sites in the sawmills processing pine and fir, were 0.24 microg/m(3) and 4.00 microg/m(3) respectively, distinctly exceeding the suggested safe level. In conclusion, the workers of Polish sawmills may be exposed on some working stands to airborne microorganisms posing respiratory hazard, of which the greatest risk is represented by allergenic fungi developing on bark of logs or stored wood products and endotoxin-producing Gram-negative bacteria of the genus Rahnella, developing in sapwood of coniferous logs

Air Microbiology↗
PubMed2003

[Carbon budget of ecosystem in Changbai Mountain Natural Reserve].

The study used EPPML, a biological geochemistry cycle model that was built, to simulate the carbon budget for ecosystems in Changbai Mountain Natural Reserve. The results indicated that the annual net primary productivity [NPP (carbon)] of the natural reserve was 1.332 x 10(6) t.a-1. The annual NPP of mixed broad-leaved and Korean pine forest and spruce-fir forest were maximal, 0.540 x 10(6) t.a-1 and 0.428 x 10(6) t.a-1 respectively. The area and productivity of the two stands were maximal in Changbai Mountain, therefore, the simulating productivity of the two stands most greatly affect carbon cycle and carbon budget of the natural reserve, and the veracity of the former decides the security of the latter. To sum up, not only did the simulations accord with routines in the relative comparisons between different vegetation belts and climate belts in the whole natural reserve, but also was exact in the absolute comparisons with very disperse data from field survey. Vegetations in the natural reserve had evident carbon sink functions, mainly exhibiting in the increasing of carbon, about 1.058 x 10(6) t.a-1. The annual carbon of mixed broad-leaved and Korean pine forest increased greatest (0.452 x 10(6) t.a-1), secondly spruce-fir forest (0.339 x 10(6) t.a-1). The two stands played crucial roles in the carbon sink for Changbai Mountain, others being Changbai larch forest, broad-leaved forest, meadow, shrub, alpine tundra, subalpine Betula ermanii forest and alpine grass. In 1995, the decomposing carbon of soil organic matter was 0.169 x 10(6) t.a-1 higher than the littering carbon in the natural reserve. There was accumulation of organic matter in the meadow soil and shrub soil. The decomposition and accumulation of soil organic matter was in the nearly balancing condition in the alpine tundra soil and alpine grass soil. The decomposition of organic matter was as one and a half time or double as litterfall in the arbor forest soil.

Carbon↗
PubMed2000

[The FAR-IR study of several mono and disaccharides and metal-sugar complexes in solid state].

FIR spectra of saccharides have many peaks. Each saccharide has its characteristic spectrum. The first, the second, the third, the fourth strongest peak appear at different regions(a, b, c, d) and the sequence (the first in a, the second in b, the third in c, the fourth in d) is characteristic. Due to the sequence in relative intensity is different, we use a simple method encoding four strong peaks to distinguish between different saccharides. We divide 500-100 cm-1 into ten ranges and encode each region as follows: 1(100-140 cm-1); 2(141-180 cm-1); 3(181-220 cm-1); 4(221-260 cm-1); 5(261-300 cm-1); 6(301-340 cm-1); 7(341-380 cm-1); 8(381-420 cm-1); 9(421-460 cm-1); 0(461-500 cm-1). For example, the codes of xylose are 6,538 and the codes of d-arabinose are 7 486. Each saccharide has a number. In this way, we can easily differentiate between saccharides. When the complexes have formed, there are broad peaks of M-O. The phenomena illustrate that FIR technique is an useful mean to determine the formation of the complexes and possibly detect their structures.

Disaccharides↗
PubMed2005

[Identification of Regulatory Sequence of lip Genes of Phanerochaete chrysosporium under Lignin-degradation.].

Eleven subcloned DNA fragments from the 5'- upstream region of lipA, lipC and lipF of Phanerochaete chrysosporium were assayed by using the gel mobility shift assay(GMSA). The total proteins extracted from P.chrysosporium mycelia grown in Kirk medium and natural fir wood chip were used to identify the segments in these 11 DNA fragments which are controlled by some regulatory proteins. The results showed that two DNA segments LG2P3(396bp) and LG6S1-2 (738bp) in the 5'-noncoding regions of lipC and lipF were able to specifically bind total mycelial proteins of P. chrysosporium incubated in Kirk medium, separately. One DNA segment LG6S2 (226bp) from the 5'-noncoding region of lipF was found to specifically bind total mycelial proteins of this fungus on natural fir wood chip. Analysis of the sequences showed that there were many cis-regulatory elements in these DNA segments, implying that these sequences may be bound by some transcriptional regulation protein factors.

Base Sequence↗
PubMed2005

Response of antioxidative enzymes of Abies firma seedlings under chronic acid fog exposure and/or drought treatment.

To understand the oxidative stress conditions of momi fir (Abies firma Sieb. et Zucc.) seedlings under acid fog exposure and/or drought stress, we assayed the activities of antioxidative enzymes, such as superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), in the seedlings. We found that SOD and APX activities were not affected by the stress conditions, but drought stress stimulated CAT activity irrespective of acid fog exposure. This suggests the production of a large amount of hydrogen peroxide, which is one of the substances involved in the signal transduction pathway for stomatal closure. However, we previously observed sufficient stomatal closure under drought stress and insufficient stomatal closure under combined acid fog exposure and drought stress. This inconsistency indicates that acid fog exposure affects the signal transduction pathway from the production of hydrogen peroxide to stomatal closure in momi fir seedlings.

Abies↗
PubMed2005

[Understory vegetation composition and main woody population niche of artificial masson pine forest in south subtropical area].

This paper studied the characteristics of the natural understory vegetation in the artificial masson pine forest replanted after Chinese fir cut for 13 years. The results indicated that there were 100 species of understory vegetation, including 74 species of shrub or small arbor, accounting for 74.0% of the total species, belonging to 41 faculties and 63 categories, and 26 herbs belonging to 14 faculties and 23 categories. The tropical and subtropical elements were dominant in the vegetation, while the temperate ones were scare. The species diversity and richness were decreased after masson pine regenerated from Chinese fir. The analysis of important value showed that the main species of shrub or small arbor were Tinomiscium tonkinensis, Mycetia longiflora, Evodia lepta, Paederia scandens, Mussaenda pubuscens, Actinodaphne pilosa and Quercus glauca, and those of herb were Cyrtococcum patens, Blechnunm orientale, Dicranopteris dichotoma, Adiantum flabellulatum, Adiantum edgeworthii and Pteris semipinnata. The biomass of the vegetation in different slope positions was decreased in order of upside> downside > middle part. There was a significantly positive correlation between the niche breath and the important value of main woody population. The important values of woody populations were higher than those of the others, and their niche breadths were also larger, which meant that they were more adaptable to the habitat. The niche overlaps of six population counterparts Tinomiscium tonkinensis-Mycetia longiflora, Tinomiscium tonkinensis-Evodia lepta, Mussaenda pubuscens-Maesa japonica, Quercus glauca-Aphananthe aspera, Actinodaphne pilosa-Saraca chinensis and Evodia lepta-Quercus glaucathese were very large, which could offer information for the restoration and reconstruction in selecting natural vegetation. The large niche overlaps of major woody population counterparts suggested their similar utilization of natural resources.

Biodiversity↗
PubMed1990

Incrimination of Aedes provocans as a vector of Jamestown Canyon virus in an enzootic focus of northeastern New York.

A 2-year field study was conducted in southern Saratoga County, New York, to determine which species of the Aedes communis group mosquitoes were potential vectors of Jamestown Canyon (JC) virus. A total of 23,890 mosquitoes (890 pools) were processed for virus isolation in 1988-89, yielding 17 JC virus isolates from Ae. provocans and one isolate each from Ae. communis, Ae. intrudens and Ae. punctor. Minimum field infection rates (MFIR) and daily MFIRs as high as 1:219 and 1:38, respectively, were found in adult female Ae. provocans. Virus isolation attempts from an additional 394 individual Ae. provocans produced a seasonal field infection rate (FIR) of 1:131 and daily FIRs of 1:71 and 1:22. Evidence of transovarial transmission of JC virus was demonstrated by the isolation of virus from 2 pools each of 50 male Ae. provocans reared in the insectary from pupae collected at the study site in 1989. We conclude that Ae. provocans is a potentially important vector of JC virus in northeastern New York.

Aedes↗
PubMed1984

Neutrophil-mediated killing of Dipetalonema viteae microfilariae: simultaneous presence of IgE, IgG antibodies and complement is required.

Neutrophils from the peripheral washings of normal rats in the presence of sera obtained from rats immune to circulating microfilariae adhered to and killed the microfilariae of Dipetalonema viteae in vitro within 16-24 hr. No significant adherence or cytotoxicity was mediated by sera collected from animals with a high microfilaraemia or from normal rats. Ultrastructural studies show that neutrophils, which are bigger than microfilariae, can easily internalize the small larvae resulting in the disintegration of the parasite. Immunoadsorption and inhibition experiments showed that the adherence-promoting activity resides both in IgG and IgE classes of antibody. However, the mere participation of these two antibodies is not sufficient to effect neutrophil adherence towards microfilariae, the presence of complement is also required. Samples of fresh immune rat serum (fIRS) depleted in alternative pathway components of complement by treatment with zymosan A failed to mediate cell adherence to the parasite. fIRS inactivated for the classical pathway of complement by the chelating agent EGTA partially retains its activity in mediating cytotoxicity to microfilariae. The striking antigenic specificity of D. viteae antibodies was shown by their ability to mediate cytotoxicity only to D. viteae but not towards Brugia malayi microfilariae.

Animals↗
PubMed1994

[Role of the conditions of recording and analysis of the atrial signal on the results of ECG signal averaged P wave].

Several studies have shown that high amplification and averaging of the electrocardiographic P wave may soon enable better identification of people at high risk of paroxysmal atrial fibrillation. The results of this technique are closely dependent on the conditions of recording and analysis of the atrial signal but this factor has not been widely appreciated. The authors, therefore, undertook a study of the reliability of the manual method of measuring P wave duration, the influence of the filters used and the level of background noise on the 3 parameters of analysis: the duration of the P wave (DUR), the root mean square of the amplitude of the terminal 20 milliseconds (RMS20) and the integral under the P curve (IN). The recorder was a Predictor II 5.0 (Corazonix) with a special programme to identify and analyse the P wave in 3 bipolar non-orthogonal leads. DUR was determined manually after amplification and averaging; RMS20 and IN were calculated automatically. In order to assess the reliability of manual determination of the P wave, 48 consecutive patients were studied: two analyses were made with a least a 2 months' interval by entering the data through two filters (unidirectional and FIR). The role of the filters was then studied by passing the preceding 48 recordings to an analysis with three filters: unidirectional, bidirectional and FIR, and comparing the results.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Fibrillation↗
PubMedDate not supplied

Liquid chromatographic determination of RH-5992, an ecdysone agonist, in some forestry matrixes.

A liquid chromatographic method is described for the analysis of RH-5992 (N'-t-butyl-N'-[3,5-dimethyl-benzoyl]-N- [-ethylbenzoyl]hydrazine) from various terrestrial and aquatic forestry matrixes and stream water. The processed soils, litter, oak foliage, sediment, aquatic plants, and fish were extracted with a mixture of acetone and water; balsam fir needles were extracted with acidified methanol solution; stream water was extracted with dichloromethane. Aliquots of crude extracts were solvent partitioned, concentrated, and cleaned up by using Florisil or Prepsep-NH2 columns. After fractional elution of the columns with hexane-ethyl acetate as the eluent, the eluates were analyzed on a liquid chromatograph equipped with a diode-array UV detector set at 236 nm, using an RP-8, 10 microns column with a mobile phase of acetonitrile-dioxane-water. Fir needles required methanol in addition to the 3 solvents in the mobile phase mixture. Water samples did not require any column cleanup. Mean recoveries for the analyte ranged from 84 to 98%, with coefficients of variation from 5 to 10%. Limits of detection (LOD) and limits of quantitation (LOQ) ranged from 0.004 to 0.030 ppm and from 0.013 to 0.101 ppm, respectively, for various forestry matrixes. LOD and LOQ for natural waters were 0.050 and 0.166 ppb, respectively.

Chromatography, Liquid↗