scholarly journals The inhibition of human platelet function by ganodermic acids

1991 ◽  
Vol 277 (1) ◽  
pp. 189-197 ◽  
Author(s):  
C N Wang ◽  
J C Chen ◽  
M S Shiao ◽  
C T Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Time Dependent ◽  
Second Phase ◽  
Phosphoinositide Metabolism ◽  
Prolonged Incubation ◽  
Dependent Inhibition ◽  
Time Dependent Inhibition ◽  
Inhibition Of Thrombin ◽  
Scanning Electron

Human gel-filtered platelets aggregate at greater than 20 microM-ganodermic acid S [lanosta-7,9(11),24-triene-3 beta, 15 alpha-diacetoxy-26-oic acid] [Wang, Chen, Shiao & Wang (1989) Biochim. Biophys. Acta 986, 151-160]. This study showed that platelets at less than 20 microM-ganodermic acid S displayed both concentration- and time-dependent inhibition of function, in which the agent potency in response to inducers was ADP-fibrinogen greater than collagen greater than thrombin. The agent caused a biphasic time-dependent effect on platelet phosphoinositide metabolism. The first phase involved the decrease in the pool size of phosphoinositide by 10-20%. The second phase, in which both the resynthesis of phosphatidylinositol 4,5-bisphosphate (PIP2) and the decrease of [32P]phosphatidic acid occurred, took place after 30 min. Scanning electron microscopy also revealed a time-dependent morphological change in platelets in the presence of the agent. The cells initially became spiculate discs, then swelled to a ‘potato-like’ morphology at 60 min. Further studies on the time-dependent inhibition of thrombin response revealed that: (1) the percentage inhibition of cell aggregation was comparable with that occurring with an increase of cytosolic free Ca2+ concentration [(Ca2+]i) or the phosphorylation of marker proteins; (2) [32P]Pi-labelled platelets showed the time-dependent inhibition of thrombin-stimulated PIP2 resynthesis as indicated by first-2-min time-course studies of phosphoinositide interconversion; (3) scanning electron microscopy revealed that the aged platelet population showed an increase in the percentage of non-responding cells on prolonged incubation. The results, taken together, enabled one to discuss a possible mechanism for the time-dependent inhibition by ganodermic acid S of platelet response to thrombin.

scholarly journals Multidisciplinary Approach Applied to the Diagnosis of the Facade of the Arciprestal Church of Santa María de Morella (Castellón, Spain)

Scanning ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Livio Ferrazza ◽  
María T. Pastor Valls ◽  
Gemma M. Contreras Zamorano ◽  
David Juanes Barber ◽  
Roxana Radvan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Multidisciplinary Approach ◽  
Polarized Light ◽  
Second Phase ◽  
Wall Paintings ◽  
Preventive Conservation ◽  
X Ray ◽  
Santa Maria ◽  
Scanning Electron

This paper deals with the development of a multidisciplinary study on the current state of conservation of the facade of the Arciprestal Church of Santa María de Morella (Castellón, Spain), a work of the Gothic period of great historical and artistic value. The aim of this diagnosis was to undertake the preventive conservation actions required and increase the knowledge about the conservation of paintings on stones. During the diagnosis scanning, electron microscopy was demonstrated to be a valuable analytical method for wall paintings on stone. The facade, which since its construction has not undergone major architectural changes, has reached our days as it was configured in its creation, adding the traces of the passage of time and interventions that have suffered polychromies. Because of the conservation situation, it was decided to have an interdisciplinary project for the structural study of the work, an exhaustive study of the materials and their state of conservation. The study of the materials includes the identification of stone supports, mortars, the pictorial technique of the original and added polychromies, and the superficial patinas. On-site studies were carried out by ground penetration radar (GPR) and X-ray fluorescence (XRF). Among the techniques used in laboratory were optical polarized light microscopy (MO-LP), X-ray diffraction (XRD), scanning electron microscopy with microanalysis (SEM-EDX) and Fourier-transform infrared spectroscopy (FTIR). The study allowed to determine the different pathologies of alteration and degradation of stone substrate and polychromies, chromatic alterations, biological patinas, etc. During this study, it was demonstrated that the diagnosis of wall paintings is a complex issue that needs to be addressed in a multidisciplinary approach, where scanning electron microscopy with microanalysis is the key methodology to get a deeper understanding of subsurface characterization of wall paintings and highlight the weathering processes. In a second phase of previous studies, this technique (SEM) has been used in assessing the viability of consolidation systems and cleaning both the stone and the polychrome.

scholarly journals The Removal of HBV in Plasma by Extracorporeal Immunoadsorption from Plasma: A Potential Therapy of Hepatitis B Patients

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Zhenwei Han ◽  
Xuan Lu ◽  
Yiping Tang ◽  
Yuanyuan Yang ◽  
Qiuchen Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Monoclonal Antibody ◽  
Time Dependent ◽  
The Novel ◽  
Plasma Samples ◽  
Novel Therapy ◽  
Real Time Quantitative Pcr ◽  
Therapy Option ◽  
Scanning Electron

Objective. To establish a novel HBV specific immunoadsorbent for the removing of HBV particles.Methods. The anti-HBsAg monoclonal antibody was immobilized on sepharose beads to produce a sepharose anti-HBs column. Then the immunoadsorbent was evaluated and characterized by scanning electron microscopy. In addition, time-dependent effects of the eradication capacity of anti-HBsAg functionalized sepharose beads against HBV were investigated.Results. Proposed immunoadsorbents exhibited a favorable biocompatibility as well as specificity. With the optimized recycle time, the decontamination performance of HBV particles and quantity of HBsAg were assessed either by real-time quantitative PCR or ELISA, which showed that the immunoadsorbent could remove approximately 90% of the HBV and 90% of the HBsAg from human plasma samples.Conclusions. All these results indicated that the novel immunoadsorbent could effectively remove HBV particles and likely serve as a novel therapy option or at least supplementary for the treatment regimen of HBV.

Fracture of Polymers Under Repetitive Loading

1986 ◽  
Vol 79 ◽  
Author(s):  
J. A. Sauer ◽  
C. C. Chen
Keyword(s):  
Electron Microscopy ◽  
Molecular Weight ◽  
Scanning Electron Microscopy ◽  
Fracture Surface ◽  
Surface Morphology ◽  
Thermal Effects ◽  
Second Phase ◽  
Fracture Surface Morphology ◽  
Repetitive Loading ◽  
Scanning Electron

AbstractThe fracture surface morphology of various polymer specimens, fractured under alternating loading, has been examined by scanning electron microscopy. Illustrations are given of both typical and unusual fracture surfaces and the influence of such variables as composition, molecular weight, presence of a dispersed second phase and induced thermal effects is discussed.

Effects of Rare Earth on Microstructure and Mechanical Properties of Al-3.2Mg Alloy

2015 ◽  
Vol 817 ◽  
pp. 192-197
Author(s):  
Xin Zhang ◽  
Ze Hua Wang ◽  
Ze Hua Zhou ◽  
Jian Ming Xu ◽  
Zhao Jun Zhong ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Grain Size ◽  
Tensile Strength ◽  
Rare Earth ◽  
Second Phase ◽  
Phase Precipitation ◽  
X Ray ◽  
Scanning Electron

A series of Al-3.2Mg alloys with addition of 0~1.6 wt.% rare earth (Ce and La) were prepared. The microstructure of as-cast Al-3.2Mg alloys was investigated by optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and the tensile strength was measured. The results indicated that the addition of rare earth elements refined grain size and secondary dendrite arm spacing (SDAS), and the tensile strength was affected by means of the second-phase precipitation and the grain boundary. Accordingly, the ductility of Al-3.2Mg alloys reduced with the increasing of RE addition due to the more second-phase formation.

Microstructure and Mechanical Properties of Friction Stir Welded and Processed Joints with the Addition of Nanoparticles: A Review

2020 ◽  
Vol 6 (2) ◽  
pp. 82-90 ◽  
Author(s):  
Danial Ghahremani-Moghadam ◽  
Seyedmeysam Khaleghian
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Optical Methods ◽  
Second Phase ◽  
Wear Performance ◽  
Friction Stir ◽  
Second Phase Particles ◽  
Reinforcement Distribution ◽  
Scanning Electron

Background: Friction Stir Welding (FSW) is an efficient process for solid-state joining of two different material without melting by using a non-consumable tool. FSW process was developed for the modification of metallic material microstructure. FSW requires a precise investigation of the process, microstructure, and the welds mechanical properties in order to be used in the fabrication of high- quality engineering components. Through the efforts of improving the weld's mechanical and microstructural properties and conveying the current knowledge of the friction stir to other applications, multiple new technologies have been developed over the time. One of the latest methods to fabricate high performance joints or Nanocomposites alloys is the addition of nano- reinforcements to the joint in Friction Stir Welding (FSW) or the metal matrix in Friction Stir Processing (FSP). Objective: In this study, an overview of effect of nanoparticles on mn this study, an overview of the effect of nanoparticles on microstructural and mechanical properties of the FSW/ FSP joints is presented. The review revealed that the most widely employed additions are SiC, SiO2, Al2O3, and graphite nano-powders. Microstructural evolutions, such as grain size, second phase particles, and reinforcement distribution, usually are investigated using optical methods and Scanning Electron Microscopy (SEM). Furthermore, the mechanical properties of the joints, such as tensile strength, hardness, and wear performance, are also investigated. Based on most of the researches, microstructural evolution associated with adding nanoparticles led to improve the joints mechanical properties.icrostructural and mechanical properties of the FSW/ FSP joints is presented. The review revealed that the most widely employed additions are SiC, SiO2, Al2O3, and graphite nano-powders. Microstructural evolutions such as grain size, second phase particles and reinforcement distribution usually are investigated using optical methods and scanning electron microscopy (SEM). Furthermore, the mechanical properties of the joints, such as tensile strength, hardness, and wear performance, are also investigated Based on most of researches, microstructural evolution associated with adding nanoparticles led to improve the joints’ mechanical properties.

scholarly journals Arylsulfatase A Remodeling during Human Sperm In Vitro Capacitation Using Field Emission Scanning Electron Microscopy (FE-SEM)

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 222
Author(s):  
María José Gómez-Torres ◽  
Natalia Huerta-Retamal ◽  
Laura Robles-Gómez ◽  
Paula Sáez-Espinosa ◽  
Jon Aizpurua ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Field Emission ◽  
Human Sperm ◽  
Time Dependent ◽  
Arylsulfatase A ◽  
Surface Mapping ◽  
Heterogeneous Distribution ◽  
Scanning Electron

Capacitation drives sperm biophysical and biochemical changes for sperm-oocyte interactions. It is a well-known fact that the molecular complex arylsulfatase A (ARSA), hyaluronidase sperm adhesion molecule 1 (SPAM1), and heat shock protein 2 (HSPA2) plays a significant role in sperm–zona pellucida (ZP) binding. However, the time-dependent capacitation effects on the sperm surface ARSA presence and specific topographic distributions remain to be elucidated. Here, we quantified the ARSA density and specific membrane domain locations before (US) and after in vitro capacitation (one and four hours; CS1–CS4) in human sperm using high-resolution field emission scanning electron microscopy (FE-SEM) and immunogold labeling. Our results showed a significant and progressive capacitation-mediated increase of labeled spermatozoa from the US (37%) to CS4 (100%) physiological conditions. In addition, surface mapping revealed a close relationship between the ARSA residues and their acrosomal repositioning. Compared with the ARSA surface heterogeneous distribution found in US, the CS1–4 conditions exhibited clustering on the peri-acrosomal region, showing that time-dependent capacitation also induced a ARSA residue dramatic translocation on sperm surfaces. Our findings provide novel insights into the molecular remodeling events preceding sperm-oocyte interactions.

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