2,141 research outputs found

    Tree Ring Characteristics of 30-Year-Old Swietenia Macrophylla Plantation Trees

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    Ring characteristics of mahogany (Swietenia macrophylla K.) plantation trees grown in Taiwan were explored. Significant differences in average ring width (RW) and ring density (RD) occurred among three tree-diameter classes and three radial stages of ring numbers. RW in the radial direction decreased from the pith outward to the bark and followed a distinctive three-stage variation pattern (juvenile, transition, and mature zones). RD in the radial direction increased slowly from the pith outward to the bark. Wider tree rings and lower density are associated with juvenile wood close to the pith, whereas narrower tree rings and higher density are typical for mature wood outward toward the bark. RD in overtopped trees was higher than that in dominant trees. However, RW in dominant trees was wider than that in intermediate and overtopped trees. Earlywood density, latewood density, maximum density, and minimum density were the most important factors determining overall RD. There was a weak relationship between RW and RD, indicating that it is unlikely for growth rates of mahogany plantation trees to have a significant impact on wood density

    Interleukin-1β Expression Is Required for Lysophosphatidic Acid-Induced Lymphangiogenesis in Human Umbilical Vein Endothelial Cells

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    Lysophosphatidic acid (LPA) is a lipid mediator which binds to G-protein-coupled receptors and regulates various cellular responses, including inflammation of endothelial cells. Interleukin- (IL-) 1β, a proinflammatory cytokine, is elevated upon LPA treatment in human umbilical vein endothelial cells (HUVECs). Previous studies indicated that LPA upregulates vascular endothelial growth factor- (VEGF-) C and lymphatic marker expressions in HUVECs. However, the relationships between LPA-induced VEGF-C and IL-1β expressions are not clear. In this paper, we demonstrated that, in the presence of AF12198, an inhibitor of the IL-1 receptor abolished LPA-induced VEGF-C and lymphatic marker expressions in HUVECs. Furthermore, LPA-induced in vitro tube formation of HUVECs was also suppressed by pretreatment with AF12198. Our results suggest that LPA-stimulated lymphangiogenesis in HUVECs is mediated through IL-1β-induced VEGF-C expression

    Atomic ionization by sterile-to-active neutrino conversion and constraints on dark matter sterile neutrinos with germanium detectors

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    The transition magnetic moment of a sterile-to-active neutrino conversion gives rise to not only radiative decay of a sterile neutrino, but also its non-standard interaction (NSI) with matter. For sterile neutrinos of keV-mass as dark matter candidates, their decay signals are actively searched for in cosmic X-ray spectra. In this work, we consider the NSI that leads to atomic ionization, which can be detected by direct dark matter experiments. It is found that this inelastic scattering process for a nonrelativistic sterile neutrino has a pronounced enhancement in the differential cross section at energy transfer about half of its mass, manifesting experimentally as peaks in the measurable energy spectra. The enhancement effects gradually smear out as the sterile neutrino becomes relativistic. Using data taken with germanium detectors that have fine energy resolution in keV and sub-keV regimes, constraints on sterile neutrino mass and its transition magnetic moment are derived and compared with those from astrophysical observations

    Esophageal Food Impaction: A Homemade Suction Tube Attached to Esophagogastroduodenoscopy for Food Bolus Removal

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    The most common esophageal foreign body in adults is impacted food bolus. Polypectomy snares, Dormia baskets, retrieval nets, rat-tooth forceps, alligator forceps or polyp graspers are usually used to remove it. Here, we report the case of a 78-year-old woman whose esophagogastroduodenoscopy (EGD) showed a firm goose liver impacted tightly in the lower esophagus; all of the above-mentioned retrieval instruments could not remove it. We used a homemade device by attaching a modified nasogastric tube to an EGD and successfully removed the goose liver by suction under endoscopic visualization. The method is very effective to remove firm and tightly impacted materials in a narrow lumen. When the usual retrieval instruments fail, a homemade suction tube attached to an EGD is an alternative

    Wear Characteristics of a Laser Surface Alloyed Al-Mg-Si with Co Alloy Powder

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    The microstructure and wear resistance of a laser surface alloyed Al-Mg-Si with Co alloy powder were investigated. The experimental results indicate that a porosity-free zone can be generated but some cracks appear after laser surface alloying (LSA). In this investigation, two regions, A (surface region) and B (bottom region), are observed in the pool. Al 9 Co 2 particles with a network structure are present in region A and block-like Al 13 Co 4 particles are distributed in region B. The hardness of the LSA specimens is three to nine times higher than that of the Almatrix. The high hardness of LSA specimens cause them to exhibit excellent sliding wear performance so they have a lower friction coefficient and wear rate. Notably, the critical temperature of the sliding wear resistance of the LSA specimen exceeds that of the Al-matrix by approximately 50 K

    CCN2 Enhances Resistance to Cisplatin-Mediating Cell Apoptosis in Human Osteosarcoma

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    Osteosarcoma (OS) is the most common form of malignant bone tumor and is an aggressive malignant neoplasm exhibiting osteoblastic differentiation. Cisplatin is one of the most efficacious antitumor drugs for osteosarcoma patients. However, treatment failures are common due to the development of chemoresistance. CCN2 (also known as CTGF), is a secreted protein that binds to integrins, modulates the invasive behavior of certain human cancer cells. However, the effect of CCN2 in cisplatin-mediated chemotherapy is still unknown. Here, we found that CCN2 was upregulated in human osteosarcoma cells after treatment with cisplatin. Moreover, overexpression of CCN2 increased the resistance to cisplatin-mediated cell apoptosis. In contrast, reduction of CCN2 by CCN2 shRNA promoted the chemotherapeutic effect of cisplatin. We also found that CCN2 provided resistance to cisplatin-induced apoptosis through upregulation of Bcl-xL and survivin. Knockdown of Bcl-xL or survivin removed the CCN2-mediated resistance to apoptosis induced by cisplatin. On the other hand, CCN2 also promoted FAK, MEK, and ERK survival signaling pathways to enhance tumor survival during cisplatin treatment. In a mouse xenograft model, overexpression of CCN2 promoted resistance to cisplatin. However, knockdown of CCN2 increased the therapeutic effect of cisplatin. Therefore, our data suggest that CCN2 might be a critical oncogene of human osteosarcoma for cisplatin-resistance and supported osteosarcoma cell growth in vivo and in vitro

    Effects of phorbol myristate acetate and sivelestat on the lung injury caused by fat embolism in isolated lungs

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    <p>Abstract</p> <p>Background</p> <p>Fat embolism syndrome (FES) associated with acute lung injury (ALI) is a clinical condition following long bone fracture. We have reported 14 victims due to ALI with FES. Our laboratory has developed an animal model that produced fat emboli (FE). The major purpose of this study was to test whether neutrophil activation with phorbol myristate acetate (PMA) and inhibition with sivelestat (SVT) exert protection on the lung.</p> <p>Methods</p> <p>The lungs of Sprague-Dawley rats were isolated and perfused. FE was produced by addition of corn oil micelles into the lung perfusate. PMA and SVT were given simultaneously with FE. Parameters such as lung weight/body weight ratio, LW gain, exhaled nitric oxide (NO), protein concentration in bronchoalveolar lavage relating to ALI were measured. The neutrophil elastase (NE), myeloperoxidase, malondialdehyde and phopholipase A<sub>2 </sub>activity were determined. We also measured the nitrate/nitrite, methyl guanidine (MG), and cytokines. Pulmonary arterial pressure and microvascular permeability were assessed. Lung pathology was examined and scored. The inducible and endothelial NO synthase (iNOS and eNOS) were detected.</p> <p>Results</p> <p>FE caused ALI and increased biochemical factors. The challenge also resulted in pulmonary hypertension and increased microvascular permeability. The NE appeared to be the first to reach its peak at 1 hr, followed by other factors. Coadministration with PMA exacerbated the FE-induced changes, while SVT attenuated the effects of FE.</p> <p>Conclusions</p> <p>The FE-induced lung changes were enhanced by PMA, while SVT had the opposite effect. Sivelestat, a neutrophil inhibitor may be a therapeutic choice for patients with acute respiratory distress syndrome (ARDS) following fat embolism.</p

    The Impact of Product innovation on Performance: The Influence of Uncertainty and Managerial Accounting Information Systems

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    This paper reports on a survey of Taiwanese high-tech firms, using a path analysis to examine the effects of managerial accounting information systems (MAIS) on the relationship between product innovation and organizational performance. Two of the major characteristics suggested by Chenhall and Morris (1986), broad scope and timeliness, are systematically related to the subject matter of this study, thus, employing these two characteristics to explore the connection between MAIS, product innovation and organizational performance. We find that product innovation has a positive effect on organizational performance through the use of MAIS, and find the extent of this positive effect is more significant in business environments marked by high levels of uncertainty. This study provides evidence to understand whether product innovation requires more extensive use of MAIS in highly uncertain environments and whether the use of MAIS can improve organizational performance. The results also help practicing managers realize the importance of MAIS in modern organizations and the benefits of using MAIS to the organization. Finally, we remind managers engaging in product innovation practices that they should place importance on the use of MAIS, because traditional cost control systems no longer help in solving the problems that are specific to the current, modern business environment
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