3,780 research outputs found

    Bioavailability of soil organic carbon and Fe as influenced by forestry practices in a subtropical coastal catchment

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    Potential impacts of plantation forestry practices on soil organic carbon and Fe available to microorganisms were investigated in a subtropical coastal catchment. The impacts of harvesting or replanting were largely limited to the soil top layer (0–10 cm depth). The thirty-year-old Pinus plantation showed low soil moisture content (Wc) and relatively high levels of soil total organic carbon (TOC). Harvesting and replanting increased soil Wc but reduced TOC levels. Mean dissolved organic carbon (DOC) and microbial biomass carbon (MBC) increased in harvested or replanted soils, but such changes were not statistically significant (P > 0.05). Total dithionite-citrate and aqua regia-extractable Fe did not respond to forestry practices, but acid ammonium oxalate and pyrophosphate-extractable, bioavailable Fe decreased markedly after harvesting or replanting. Numbers of heterotrophic bacteria were significantly correlated with DOC levels (P < 0.05), whereas Fe-reducing bacteria and S-bacteria detected using laboratory cultivation techniques did not show strong correlation with either soil DOC or Fe content

    Adhesive and mechanical regulation of mesenchymal stem cell differentiation in human bone marrow and periosteum-derived progenitor cells

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    It has previously been demonstrated that cell shape can influence commitment of human bone marrow-derived mesenchymal stem cells (hBMCs) to adipogenic, osteogenic, chondrogenic, and other lineages. Human periosteum-derived cells (hPDCs) exhibit multipotency similar to hBMCs, but hPDCs may offer enhanced potential for osteogenesis and chondrogenesis given their apparent endogenous role in bone and cartilage repair in vivo. Here, we examined whether hPDC differentiation is regulated by adhesive and mechanical cues comparable to that reported for hBMC differentiation. When cultured in the appropriate induction media, hPDCs at high cell seeding density demonstrated enhanced levels of adipogenic or chondrogenic markers as compared with hPDCs at low cell seeding density. Cell seeding density correlated inversely with projected area of cell spreading, and directly limiting cell spreading with micropatterned substrates promoted adipogenesis or chondrogenesis while substrates promoting cell spreading supported osteogenesis. Interestingly, cell seeding density influenced differentiation through both changes in cell shape and non-shape-mediated effects: density-dependent adipogenesis and chondrogenesis were regulated primarily by cell shape whereas non-shape effects strongly influenced osteogenic potential. Inhibition of cytoskeletal contractility by adding the Rho kinase inhibitor Y27632 further enhanced adipogenic differentiation and discouraged osteogenic differentiation of hPDCs. Together, our results suggest that multipotent lineage decisions of hPDCs are impacted by cell adhesive and mechanical cues, though to different extents than hBMCs. Thus, future studies of hPDCs and other primary stem cell populations with clinical potential should consider varying biophysical metrics for more thorough optimization of stem cell differentiation.R01 EB000262 - NIBIB NIH HHS; R01 GM060692 - NIGMS NIH HHSPublished versio

    East Meets West Pharmaceutically and Economically

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    Human Trafficking in Malaysia: An Opportunity to Resolve Past Failures

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    Every day, Malaysians face the risk of falling victim to the deceivingly enticing world of human trafficking. The fiurteenth general election in 2018 resulted in a new coalition, Pakatan Harapam, and brought hope for improved policies, including those concerning human trafficking. This article focuses on the challenges Malaysia faces combating this long-existing issue and provides action steps that, if instated, will greatly improve the well-being of the nation and its people

    Threats to Ocean Biodiversity

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    Overfishing Taking fish out of the ocean faster than their populations can be naturally replenishedhttps://digitalcommons.imsa.edu/unsdg_infographics/1004/thumbnail.jp

    Gender Differences in Eating Behavior

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    University students may encounter personal, family, social, and financial stresses while trying to cope with their academic challenges. Such constraints could affect their eating behavior and health status which, in turn may have negative effects on their studies. In light of little information in Malaysia on this subject, this study was undertaken on a sample of 180 students pursuing different academic programs in a Malaysian university. The study objectives were to determine the students’ eating behavior including body weight control and the extent of fear of being fat, their social self concept that reflects the five selves namely, the psychological self, the social self, the sexual self, the family self and the physical self. Eating behavior and social self concept were determined based on various methods previously validated in studies on young adults in Asia and Australia. This article focuses on gender comparisons for these determinants. The results showed that psychological and emotional factors have a significant bearing on the eating behavior of university students. Uninhibited eating behavior of both the males and females showed significant and negative correlations with feelings pertaining to personal worth, the physical self, and their relationships with peers and families. Gender differences were manifested for some determinants. The females showed more restrained eating behavior than the males; the females have a significantly higher score for family relationship, which appears to be a significant factor on male students’ eating behavior. Future studies on a larger sample size may help to unravel the extent to which psychological factors influence eating behavior of students, and the underlying psychosocial basis for some of the gender differences reported in this study. ,
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