85 research outputs found

    Contribution Factor of Wood Properties of Three Poplar Clones to Strength of Laminated Veneer Lumber

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    The term "Contribution Factor" (Cf) was introduced in this paper to indicate the contribution ratio of solid wood properties to laminated veneer lumber (LVL) strength. Three poplar (Populus sp.) clones were studied, and the results showed that poplar with good solid wood properties has high Contribution Factor. The average Contribution Factor of Poplar 69 (Populus deltoides cv. I-69/55), Poplar 72 (P. euramericana cv. I-72/58), and Poplar 63 (P. deltoides cv.I-63-51) was 76.2%, 68.6%, and 66.1%, respectively. The average Contribution Factor of the three clones for shear strength, modulus of elasticity (MOE), and impact toughness was approximately 80%, which is higher than that for modulus of rupture (MOR), compressive strength, and hardness. The average Contribution Factor of the six properties tested was highest in Poplar 69 (76.2%) and the lowest in Poplar 63 (66.1%), indicating that the Contribution Factor is positively affected by solid wood properties. Densification also significantly affects LVL MOE in Poplar 72, as compared to that of Poplar 69. Poplar 63, however, showed highest improvement in MOR strength from solid wood to LVL and also highest specific LVL MOR, even though it has the lowest solid wood MOR among the three clones

    Spatial mapping of the collagen distribution in human and mouse tissues by force volume atomic force microscopy

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    Changes in the elastic properties of living tissues during normal development and in pathological processes are often due to modifications of the collagen component of the extracellular matrix at various length scales. Force volume AFM can precisely capture the mechanical properties of biological samples with force sensitivity and spatial resolution. The integration of AFM data with data of the molecular composition contributes to understanding the interplay between tissue biochemistry, organization and function. The detection of micrometer-size, heterogeneous domains at different elastic moduli in tissue sections by AFM has remained elusive so far, due to the lack of correlations with histological, optical and biochemical assessments. In this work, force volume AFM is used to identify collagen-enriched domains, naturally present in human and mouse tissues, by their elastic modulus. Collagen identification is obtained in a robust way and affordable timescales, through an optimal design of the sample preparation method and AFM parameters for faster scan with micrometer resolution. The choice of a separate reference sample stained for collagen allows correlating elastic modulus with collagen amount and position with high statistical significance. The proposed preparation method ensures safe handling of the tissue sections guarantees the preservation of their micromechanical characteristics over time and makes it much easier to perform correlation experiments with different biomarkers independently

    Hepatitis C Virus Treatment Access Among Human Immunodeficiency Virus and Hepatitis C Virus (HCV)-Coinfected People Who Inject Drugs in Guangzhou, China: Implications for HCV Treatment Expansion.

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    Background.  Hepatitis C virus (HCV) treatment access among human immunodeficiency virus (HIV)/HCV-coinfected people who inject drugs is poor, despite a high burden of disease in this population. Understanding barriers and facilitators to HCV treatment uptake is critical to the implementation of new direct-acting antivirals. Methods.  We conducted in-depth interviews with patients, physicians, and social workers at an HIV treatment facility and methadone maintenance treatment centers in Guangzhou, China to identify barriers and facilitators to HCV treatment. We included patients who were in various stages of HCV treatment and those who were not treated. We used standard qualitative methods and organized data into themes. Results.  Interview data from 29 patients, 8 physicians, and 3 social workers were analyzed. Facilitators and barriers were organized according to a modified Consolidated Framework for Implementation Research schematic. Facilitators included patient trust in physicians, hope for a cure, peer networks, and social support. Barriers included ongoing drug use, low HCV disease knowledge, fragmented reimbursement systems, HIV exceptionalism, and stigma. Conclusions.  Expanding existing harm reduction programs, HIV treatment programs, and social services may facilitate scale-up of direct-acting antivirals globally. Improving integration of ancillary social and mental health services within existing HIV care systems may facilitate HCV treatment access

    WormQTL-public archive and analysis web portal for natural variation data in Caenorhabditis spp

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    Here, we present WormQTL (http://www.wormqtl.org), an easily accessible database enabling search, comparative analysis and meta-analysis of all data on variation in Caenorhabditis spp. Over the past decade, Caenorhabditis elegans has become instrumental for molecular quantitative genetics and the systems biology of natural variation. These efforts have resulted in a valuable amount of phenotypic, high-throughput molecular and genotypic data across different developmental worm stages and environments in hundreds of C. elegans strains. WormQTL provides a workbench of analysis tools for genotype-phenotype linkage and association mapping based on but not limited to R/qtl (http://www.rqtl.org). All data can be uploaded and downloaded using simple delimited text or Excel formats and are accessible via a public web user interface for biologists and R statistic and web service interfaces for bioinformaticians, based on open source MOLGENIS and xQTL workbench software. WormQTL welcomes data submissions from other worm researcher

    Growth Differentiation Factor 9 (GDF9) Suppresses Follistatin and Follistatin-Like 3 Production in Human Granulosa-Lutein Cells

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    We have demonstrated that growth differentiation factor 9 (GDF9) enhances activin A-induced inhibin β(B)-subunit mRNA levels in human granulosa-lutein (hGL) cells by regulating receptors and key intracellular components of the activin signaling pathway. However, we could not exclude its effects on follistatin (FST) and follistatin-like 3 (FSTL3), well recognized extracellular inhibitors of activin A.hGL cells from women undergoing in vitro fertilization (IVF) treatment were cultured with and without siRNA transfection of FST, FSTL3 or GDF9 and then treated with GDF9, activin A, FST, FSTL3 or combinations. FST, FSTL3 and inhibin β(B)-subunit mRNA, and FST, FSTL3 and inhibin B protein levels were assessed with real-time RT-PCR and ELISA, respectively. Data were log transformed before ANOVA followed by Tukey's test.GDF9 suppressed basal FST and FSTL3 mRNA and protein levels in a time- and dose-dependent manner and inhibited activin A-induced FST and FSTL3 mRNA and protein expression, effects attenuated by BMPR2 extracellular domain (BMPR2 ECD), a GDF9 antagonist. After GDF9 siRNA transfection, basal and activin A-induced FST and FSTL3 mRNA and protein levels increased, but changes were reversed by adding GDF9. Reduced endogenous FST or FSTL3 expression with corresponding siRNA transfection augmented activin A-induced inhibin β(B)-subunit mRNA levels as well as inhibin B levels (P values all <0.05). Furthermore, the enhancing effects of GDF9 in activin A-induced inhibin β(B)-subunit mRNA and inhibin B production were attenuated by adding FST.GDF9 decreases basal and activin A-induced FST and FSTL3 expression, and this explains, in part, its enhancing effects on activin A-induced inhibin β(B)-subunit mRNA expression and inhibin B production in hGL cells

    Bees in China: A Brief Cultural History

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    Economic growth in the Lower Yangzi region of China in 1911–1937: a quantitative and historical analysis

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    Through a detailed reconstruction of 1933 GDP for the two provinces in China's most advanced region, the Lower Yangzi, I show that their per capita income was 55 percent higher than China's average, and they had experienced a growth and structural change between 1914–1918 and 1931–1936 comparable to contemporaneous Japan and her East Asian colonies. This article highlights the unique political institution of early-twentieth-century Shanghai as a city state, with its rule of law and secure property rights laying the foundation for economic growth in the Lower Yangzi with long-term impact throughout East Asia
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