Stereological analysis of partially amorphous HREM images

Author(s):  
R. H. Kaspi ◽  
D. E. Luzzi

The HREM is highly sensitive to the presence of crystals in a specimen. As a results, researchers often report the presence of some fringe contrast in an otherwise amorphous image. The potential for obtaining more information than just a sense of the presence of crystal has not been addressed in detail. In the interest of allowing some amount of quantitative analysis of HREM images of partially and fully amorphous materials, we have developed an analytical method with which to quantify the directionality of an image using stereology.Figure 1 is a series of HREM images taken through the crystal - amorphous interface of an electron irradiated Cu-Ti intermetallic alloy. The first image is from an unirradiated crystalline region. The second image is from a low dose irradiated region, while the third is from a region that has been irradiated to a dose just under the necessary dosage for a total amorphous transition.

Author(s):  
T. M. Seed ◽  
M. H. Sanderson ◽  
D. L. Gutzeit ◽  
T. E. Fritz ◽  
D. V. Tolle ◽  
...  

The developing mammalian fetus is thought to be highly sensitive to ionizing radiation. However, dose, dose-rate relationships are not well established, especially the long term effects of protracted, low-dose exposure. A previous report (1) has indicated that bred beagle bitches exposed to daily doses of 5 to 35 R 60Co gamma rays throughout gestation can produce viable, seemingly normal offspring. Puppies irradiated in utero are distinguishable from controls only by their smaller size, dental abnormalities, and, in adulthood, by their inability to bear young.We report here our preliminary microscopic evaluation of ovarian pathology in young pups continuously irradiated throughout gestation at daily (22 h/day) dose rates of either 0.4, 1.0, 2.5, or 5.0 R/day of gamma rays from an attenuated 60Co source. Pups from non-irradiated bitches served as controls. Experimental animals were evaluated clinically and hematologically (control + 5.0 R/day pups) at regular intervals.


Author(s):  
T. Oikawa ◽  
N. Mori ◽  
T. Katoh ◽  
Y. Harada ◽  
J. Miyahara ◽  
...  

The “Imaging Plate”(IP) is a highly sensitive image recording plate for X-ray radiography. It has been ascertained that the IP has superior properties and high practicability as an image recording material in a TEM. The sensitivity, one of the properties, is about 3 orders higher than that of conventional photo film. The IP is expected to be applied to low dose techniques. In this paper, an estimation of the quantum noise on the TEM image which appears in case of low electron dose on the IP is reported.In this experiment, the JEM-2000FX TEM and an IP having the same size as photo film were used.Figure 1 shows the schematic diagram of the total system including the TEM used in this experiment. In the reader, He-Ne laser light is scanned across the IP, then blue light is emitted from the IP.


RSC Advances ◽  
2020 ◽  
Vol 10 (71) ◽  
pp. 43489-43496
Author(s):  
Shaghayegh Saadati ◽  
Ubong Eduok ◽  
Amira Abdelrasoul ◽  
Ahmed Shoker

Rapid and highly sensitive quantitative analysis of 3-carboxy-4-methyl-5-propyl-2-furanpropionate and indole-3-acetic acid in uremic serum of patients with chronic kidney disease.


Author(s):  
Yusuke Kawano ◽  
Kengo Suzuki ◽  
Iwao Ohtsu

Abstract Generally, volatile thiols are hard to be measured with ESI (electrospray ionization)-type LC-MS due to the volatility. Therefore, we here evaluated the pretreatment of their S-bimanyl derivatization by monobromobimane to enable the detection as nonvolatile derivative. Consequently, we successfully developed the convenient and efficient method through the quantitative analysis of 2-furanmethanethiol (volatile thiol odorant of coffee aroma) in coffee bean.


1991 ◽  
Vol 70 (4) ◽  
pp. 1447-1455 ◽  
Author(s):  
A. De Troyer

To assess the relative contributions of the different groups of inspiratory intercostal muscles to the cranial motion of the ribs in the dog, we have measured the axial displacement of the fourth rib and recorded the electromyograms of the parasternal intercostal, external intercostal, and levator costae in the third interspace in 15 anesthetized animals breathing at rest. In eight animals, the parasternal intercostals were denervated in interspaces 1-5. This procedure caused a marked increase in the amount of external intercostal and levator costae inspiratory activity, and yet the inspiratory cranial motion of the rib was reduced by 55%. On the other hand, the external intercostals in interspaces 1-5 were sectioned in seven animals, and the reduction in the cranial rib motion was only 22%; the amount of parasternal and levator costae activity, however, was unchanged. When the parasternals in these animals were subsequently denervated, the levator costae inspiratory activity increased markedly, but the inspiratory cranial motion of the rib was abolished or reversed into an inspiratory caudal motion. These studies thus confirm that, in the dog breathing at rest, the parasternal intercostals have a larger role than the external intercostals and levator costae in causing the cranial motion of the ribs during inspiration. A quantitative analysis suggests that the parasternal contribution is approximately 80%.


2011 ◽  
Vol 26 (S2) ◽  
pp. 164-164
Author(s):  
F. M-Hasan

The March 1988 genocide in Halabja, in which 4000–7000 Kurdish women, children and men were killed by the then Iraqi regime, was the most brutal gas attack on a civil population in modern history. This study challenges currently held understandings of PTSD and how traumatic transformations are expressed in other parts of the world; thereby contributing to the new field of traumatology. The study is quantitative analysis of the prevalence of PTSD, measured using (IES), in two Kurdish towns; Halabja and Suleimaniyah, encompassing 110 participants. The study's primary aim was to compare the prevalence of PTSD in Halabja with that in Suleimaniyah which was not attacked, the expectation being that PTSD would be more prevalent in Halabja than in Suleimaniyah. secondly, that women and those with shorter education would report a higher prevalence of PTSD symptoms, and thirdly that participants with higher levels of social support would report a lower prevalence of PTSD symptoms. The results showed that the prevalence of PTSD symptoms in total, of reliving and of hyperarousal in the trauma exposed town was significantly higher than in Suleimaniyah, thus supporting the primary hypothesis. The results further showed a significant connection between sex and PTSD symptoms and a clear linear relation between education and prevalence of PTSD symptoms, thus supporting the second hypothesis. However, the results showed no support for the third hypothesis. The study thus indicates that researchers and practitioners working with PTSD need a broader cultural understanding to carry out studies in best possible manner.


2021 ◽  
Author(s):  
George Courcoubetis ◽  
Chi Xu ◽  
Sergey Nuzhdin ◽  
Stephan Haas

AbstractIn the physicists’ perspective, epithelial tissues constitute an exotic type of active matter with non-linear properties reminiscent of amorphous materials. In the context of a circular proliferating epithelium, modeled by the quasistatic vertex model, we identify novel discrete tissue scale rearrangements, i.e. cellular flow avalanches, which are a form of collective cell movement. During the avalanches, the cellular trajectories are radial in the periphery and form a vortex in the core. After the onset of these avalanches, the epithelial area grows discontinuously. The avalanches are found to be stochastic, and their strength is determined by the density of cells in the tissue. Overall, avalanches regularize the spatial tension distribution along tissue. Furthermore, the avalanche distribution is found to obey a power law, with an exponent consistent with sheer induced avalanches in amorphous materials. To decipher the role of avalanches in organ development, we simulate epithelial growth of theDrosophilaeye disc during the third instar using a computational model, which includes both signaling and mechanistic signalling. During the third instar, the morphogenetic furrow (MF), a ∼10 cell wide wave of apical area constriction propagates through the epithelium, making it a system with interesting mechanical properties. These simulations are used to understand the details of the growth process, the effect of the MF on the growth dynamics on the tissue scale, and to make predictions. The avalanches are found to depend on the strength of the apical constriction of cells in the MF, with stronger apical constriction leading to less frequent and more pronounced avalanches. The results herein highlight the dependence of simulated tissue growth dynamics on relaxation timescales, and serve as a guide forin vitroexperiments.


2021 ◽  
Author(s):  
Anri Hirai ◽  
Ryo Yamazaki ◽  
Atsushi Kobayashi ◽  
Takashi Kimura ◽  
Kei Nomiyama ◽  
...  

Abstract Monoamine neurotransmitters (MAs), including dopamine (DA) and serotonin (5-HT), regulate brain functions such as behavior, memory, and learning. Neonicotinoids are pesticides that are being used more frequently. Neonicotinoid exposure has been observed to produce neurological symptoms, such as altered spontaneous movements and anxiety-like behaviors, which are suspected to be caused by altered MA levels. However, current neurotoxicity tests are not sufficiently sensitive to make these determinations. In this study, we performed some behavior tests and developed a sensitive and accurate analytical method using liquid chromatography-mass spectrometry (LC-MS/MS) to clarify the effects of neonicotinoid administration on MAs in the brain.We orally administered the neonicotinoid imidacloprid (0, 10, and 50 mg/kg body weight) to C57BL/6NCrSlc mice. In behavior tests, the decrease of activity was observed. The LC-MS/MS quantification of MAs in various brain regions by tetrafluoroborate salt of 2,4-diphenyl-pyranylium (DPP) derivatization, which was newly developed in this study, showed a decrease in some MA levels in the olfactory bulb and the striatum.Thus, in this study, we developed a new method for the sensitive detection of MAs by LC/MS using DPP derivatization. In addition, we showed that this sensitive MA quantification is effective in clarifying the neurotoxicity caused by chemical substances.


1997 ◽  
Vol 38 (412_suppl) ◽  
pp. 51-55
Author(s):  
B. Misselwitz ◽  
A. Sachse

The detection of metastasis in lymph nodes is greatly enhanced by the use of contrast media. Interstitial injection of lymphography contrast agents requires only injection of a low dose of the agent, and leads to high accumulation in regional lymph nodes with only minor side effects. We were able to show the suitability of liposome-encapsulated gadobutrol as an interstitially injectable lymphography contrast agent in an experimental animal model. For screening of possible lymphotrophic compounds a guinea pig model was used. Accumulation of the contrast agent in 3 successive lymph node groups was determined 4 h after subcutaneous injection of the contrast agent (about 0.1 ml of a 30 mmol Gd/1 solution resulting in a total dose of 10 μmol/kg) into the interdigital skin fold of a hind limb. The Gd concentration in the first lymph node group (popliteal) was 540 μmol/1 (16% dose/g tissue), in the second group (inguinal): 260 μmol/1 (8% dose/g tissue), and in the third group (iliacal): 910 μmol/1 (27% dose/g tissue). Moreover, this compound was completely eliminated and well tolerated.


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