Ratio of cell diameter to dislocation spacing for creep of Zircaloy-4

1983 ◽  
Vol 48 (5) ◽  
pp. 759-766 ◽  
Author(s):  
F. Povolo ◽  
A. J. Marzocca ◽  
J. C. Capitani
Author(s):  
Julius Honecker ◽  
Dominik Weidlich ◽  
Simone Heisz ◽  
Cecilia M. Lindgren ◽  
Dimitrios C. Karampinos ◽  
...  

Abstract Objective Cell diameter, area, and volume are established quantitative measures of adipocyte size. However, these different adipocyte sizing parameters have not yet been directly compared regarding their distributions. Therefore, the study aimed to investigate how these adipocyte size measures differ in their distribution and assessed their correlation with anthropometry and laboratory chemistry. In addition, we were interested to investigate the relationship between fat cell size and adipocyte mitochondrial respiratory chain capacity. Methods Subcutaneous and visceral histology-based adipocyte size estimates from 188 individuals were analyzed by applying a panel of parameters to describe the underlying cell population. Histology-based adipocyte diameter distributions were compared with adipocyte diameter distributions from collagenase digestion. Associations of mean adipocyte size with body mass index (BMI), glucose, HbA1C, blood lipids as well as mature adipocyte mitochondrial respiration were investigated. Results All adipocyte area estimates derived from adipose tissue histology were not normally distributed, but rather characterized by positive skewness. The shape of the size distribution depends on the adipocyte sizing parameter and on the method used to determine adipocyte size. Despite different distribution shapes histology-derived adipocyte area, diameter, volume, and surface area consistently showed positive correlations with BMI. Furthermore, associations between adipocyte sizing parameters and glucose, HbA1C, or HDL specifically in the visceral adipose depot were revealed. Increasing subcutaneous adipocyte diameter was negatively correlated with adipocyte mitochondrial respiration. Conclusions Despite different underlying size distributions, the correlation with obesity-related traits was consistent across adipocyte sizing parameters. Decreased mitochondrial respiratory capacity with increasing subcutaneous adipocyte diameter could display a novel link between adipocyte hypertrophy and adipose tissue function.


Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1872
Author(s):  
James Anthony Dicks ◽  
Chris Woolard

The environmental issues of petroleum-derived polymeric foams have necessitated seeking renewable alternatives. This work aims to prepare renewable free-radically polymerized polymeric foams with the ability to biodegrade. Furthermore, this work attempted to incorporate a bio-based reactive diluent, which has not been reported in the literature. The synthesis of maleated castor oil glycerides was performed with products analyzed by Fourier transform infrared spectrometry using attenuated total reflection (ATR-FTIR) and 1H nuclear magnetic resonance (1H NMR) spectroscopy. Polymeric foams were prepared using maleated castor oil glycerides via free radical copolymerization with styrene and isobornyl methacrylate as reactive diluents. Scanning electron microscopy (SEM) was used to determine anisotropic macrocellular morphology, with log-normal cell diameter distributions. The compressive mechanical and energy absorption properties were investigated; the polymeric foams displayed Young’s modulus up to 26.85 ± 1.07 MPa and strength up to 1.11 ± 0.021 MPa using styrene as the reactive diluent, and Young’s modulus up to 1.38 ± 0.055 MPa and strength up to 0.088 MPa when incorporating isobornyl methacrylate. Furthermore, a thorough analysis of the cellular structure–property relationships was performed, indicating relationships to cell diameter, cell wall thickness and apparent density. The polymeric foams displayed rapid mass loss in an aerobic soil environment with multiple erosion sites revealed by SEM. In conclusion, renewable polymeric foams with excellent compressive properties were achieved using styrene as reactive diluent, but the incorporation of isobornyl methacrylate decreased strength-related properties.


e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 103-110
Author(s):  
Anfu Guo ◽  
Hui Li ◽  
Jie Xu ◽  
Jianfeng Li ◽  
Fangyi Li

AbstractThe performance of Polystyrene microporous foaming (PS-MCF) materials is influenced by their microstructures. Therefore, it is essential for industrializing them to investigate the relationship between their microstructure and material properties. In this study, the relationship between the microstructure, compressive property, and thermal conductivity of the PS-MCF materials was studied systematically. The results show that the ideal foaming pressure of PS-MCF materials, obtaining compression performance, is around 20 MPa. In addition, the increase of temperature causes the decrease of sample density. It effects that the compression modulus and strength increase with the decrease of foaming temperature. Because the expansion rate and cell diameter of the PS-MCF materials reduce the thickness of cell wall, they are also negatively correlated with their mechanical properties. Moreover, there is a negative linear correlation between the thermal conductivity and cell rate, whereas the cell diameter is positively correlated with the thermal conductivity.


2021 ◽  
Vol 13 (2) ◽  
pp. 231
Author(s):  
John A. Gittings ◽  
Dionysios. E. Raitsos ◽  
Robert J. W. Brewin ◽  
Ibrahim Hoteit

Phytoplankton phenology and size structure are key ecological indicators that influence the survival and recruitment of higher trophic levels, marine food web structure, and biogeochemical cycling. For example, the presence of larger phytoplankton cells supports food chains that ultimately contribute to fisheries resources. Monitoring these indicators can thus provide important information to help understand the response of marine ecosystems to environmental change. In this study, we apply the phytoplankton size model of Gittings et al. (2019b) to 20-years of satellite-derived ocean colour observations in the northern and central Red Sea, and investigate interannual variability in phenology metrics for large phytoplankton (>2 µm in cell diameter). Large phytoplankton consistently bloom in the winter. However, the timing of bloom initiation and termination (in autumn and spring, respectively) varies between years. In the autumn/winter of 2002/2003, we detected a phytoplankton bloom, which initiated ~8 weeks earlier and lasted ~11 weeks longer than average. The event was linked with an eddy dipole in the central Red Sea, which increased nutrient availability and enhanced the growth of large phytoplankton. The earlier timing of food availability directly impacted the recruitment success of higher trophic levels, as represented by the maximum catch of two commercially important fisheries (Sardinella spp. and Teuthida) in the following year. The results of our analysis are essential for understanding trophic linkages between phytoplankton and fisheries and for marine management strategies in the Red Sea.


2021 ◽  
Vol 15 (8) ◽  
pp. 1788-1789
Author(s):  
Tazeen Kohari ◽  
Farah Malik ◽  
Aftab Ahmad

Background: The histology of Cerebellar gray matter consists of a middle Purkinje cells layer with flask shaped Purkinje cells. The field of Neurology has documented that different organic compounds and metals are lethal to the excitatory Purkinje Neurons. Researches have proved Lithium to be hazardous to nervous tissue and especially Cerebellum For the past sixty years Lithium is the favorable drug for treatment of Bipolar Disorder. Aim: To Analyse and record the changes of decrement of the size of Purkinje cell Diameter after chronic Lithium ingestion. Methods: Sixteen albino rats were selected and were treated with lithium for a period of fifteen days and the data for changes in Purkinje cells Diameter was observed. Results: The Observations of Our study showed highly significantly decreased diameter of the Purinje cells in Group B (Lithium Carbonate) animals as compared to Group A Animals which were on Lab Diet Conclusion: The Morphometric Data proved that Lithium Carbonate is Toxic to Purkinje cells, and it educated our Population to use Lithium with caution. Keywords: Purkinje cell Diameter, Gray matter, Hazardous


2021 ◽  
Author(s):  
Ji Zhou ◽  
Huijun Li ◽  
Cong Fang ◽  
Junye Tan ◽  
Peng Gao ◽  
...  

Abstract Objectives. Early detection of malignant tumour is a prerequisite for a successful treatment. Here we investigate if thymidine kinase 1 is more sensitive than imaging technology to discover small invisible malignant tumours.Material and Methods. The cellular concentration of TK1 was determined by a novel automatic chemiluminescence analyzer of magnetic particle immune sandwich minimum. The primary and secondary antibodies linked to the magnetic beads were chicken anti-human thymidine kinase 1 IgY-polyclonal antibodies (IgY pAb). The minimum number of cells able to be detected by the novel detection technology using an automatic chemiluminescence analyzer were determined based on the cellar TK1 concentration of low and high TK1 cell lines of known cell count.Results. The TK1 concentration of malignant cell was found to be 0.021 pg/cell. Assuming 200 pg of total protein/cell, TK1 corresponds to 0.01 % of the total protein/cell. The concentration of TK1 in human blood serum of malignant patients is in the range of 2-10 pmol/l (pM), corresponding to about 50 x106 growing cells in the body that release TK1 into 5 litre blood. The limit visibility by imaging of a tumour is about 1 mm in diameter, corresponding to about 109cells of a cell diameter of 1µm. Conclusion. TK1 is more sensitive than imaging.


2017 ◽  
Vol 14 (16) ◽  
pp. 3831-3849 ◽  
Author(s):  
Katharine J. Crawfurd ◽  
Santiago Alvarez-Fernandez ◽  
Kristina D. A. Mojica ◽  
Ulf Riebesell ◽  
Corina P. D. Brussaard

Abstract. Ocean acidification resulting from the uptake of anthropogenic carbon dioxide (CO2) by the ocean is considered a major threat to marine ecosystems. Here we examined the effects of ocean acidification on microbial community dynamics in the eastern Baltic Sea during the summer of 2012 when inorganic nitrogen and phosphorus were strongly depleted. Large-volume in situ mesocosms were employed to mimic present, future and far future CO2 scenarios. All six groups of phytoplankton enumerated by flow cytometry ( <  20 µm cell diameter) showed distinct trends in net growth and abundance with CO2 enrichment. The picoeukaryotic phytoplankton groups Pico-I and Pico-II displayed enhanced abundances, whilst Pico-III, Synechococcus and the nanoeukaryotic phytoplankton groups were negatively affected by elevated fugacity of CO2 (fCO2). Specifically, the numerically dominant eukaryote, Pico-I, demonstrated increases in gross growth rate with increasing fCO2 sufficient to double its abundance. The dynamics of the prokaryote community closely followed trends in total algal biomass despite differential effects of fCO2 on algal groups. Similarly, viral abundances corresponded to prokaryotic host population dynamics. Viral lysis and grazing were both important in controlling microbial abundances. Overall our results point to a shift, with increasing fCO2, towards a more regenerative system with production dominated by small picoeukaryotic phytoplankton.


Polymers ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 796 ◽  
Author(s):  
Le Yang ◽  
Zaijun Yang ◽  
Feng Zhang ◽  
Lijin Xie ◽  
Zhu Luo ◽  
...  

Long chain branched poly (lactic acid) (LCBPLA) was prepared via transesterification between high molecular weight poly (lactic acid) (PLA) and low molar mass monomer trimethylolpropane triacrylate (TMPTA) during melt blending in the presence of zinc oxide nanoparticles (nano-ZnO) as a transesterification accelerant in a torque rheometer. Compared with the traditional processing methods, this novel way is high-efficiency, environmentally friendly, and gel-free. The results revealed that chain restructuring reactions occurred and TMPTA was grafted onto the PLA backbone. The topological structures of LCBPLA were verified and investigated in detail. It was found that the concentration of the accelerants and the sampling occasion had very important roles in the occurrence of branching structures. When the nano-ZnO dosage was 0.4 phr and PLA was sampled at the time corresponding to the reaction peak in the torque curve, PLA exhibited a star-shaped topological structure with a high branching degree which could obviously affect the melt strength, extrusion foaming performances, and crystallization behaviors. Compared with pristine PLA, LCBPLA showed a higher melt strength, smaller cell diameter, and slower crystallization speed owing to the synergistic effects of nano-ZnO and the long chain branches introduced by the transesterification reaction in the system. However, severe degradation of the LCBPLAs would take place under a mixing time that was too long and lots of short linear chains generated due to the excessive transesterification reaction, with a sharp decline in melt strength.


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