scholarly journals Evaluation of plasticity during deformation of carbon steel

2019 ◽  
pp. 85-88
Author(s):  
V. Р. Fetisov
Keyword(s):  
Carbon Steel ◽  
Deformation Temperature ◽  
Structural Parameters ◽  
Internal Stresses ◽  
Relative Reduction ◽  
Sectional Area ◽  
Cross Sectional ◽  
Plastic Properties ◽  
Relative Contraction

The indicator of the degree of relative reduction of the cross-sectional area and the indicator of the degree of development of the necking, more sensitive to changes in the structural parameters and the deformation temperature of carbon steel compared to the traditional were proposed in comparison with the relative contraction and the true deformation index. The role of relaxation of internal stresses and increased mobility of dislocations in the formation of plastic properties of carbon steel is considered.

Role of diffusion tensor imaging in the evaluation of ulnar nerve involvement in leprosy

2021 ◽  
pp. 20210290
Author(s):  
Ankita Aggarwal ◽  
Chandan Jyoti Das ◽  
Neena Khanna ◽  
Raju Sharma ◽  
Deep Narayan Srivastava ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Peripheral Neuropathy ◽  
Ulnar Nerve ◽  
Diffusion Tensor ◽  
Cross Sectional Area ◽  
Ulnar Neuropathy ◽  
Control Group ◽  
Sectional Area ◽  
Cross Sectional

Objective: Early detection of peripheral neuropathy is extremely important as leprosy is one of the treatable causes of peripheral neuropathy. The study was undertaken to assess the role of diffusion tensor imaging (DTI) in ulnar neuropathy in leprosy patients. Methods: This was a case–control study including 38 patients (72 nerves) and 5 controls (10 nerves) done between January 2017 and June 2019. Skin biopsy proven cases of leprosy, having symptoms of ulnar neuropathy (proven on nerve conduction study) were included. MRI was performed on a 3 T MR system. Mean cross-sectional area, fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of ulnar nerve at cubital tunnel were calculated. Additional ancillary findings and appearance of base sequences were evaluated. Results: Ulnar nerve showed thickening with altered T2W signal in all the affected nerves, having an average cross-sectional area of 0.26 cm2. Low FA with mean of 0.397 ± 0.19 and high ADC with mean of 1.28 ± 0.427 x 10 −3 mm2/s of ulnar nerve in retrocondylar groove was obtained. In the control group, mean cross-sectional area was 0.71cm2 with mean FA and ADC of 0.53 ± 0.088 and 1.03 ± 0.24 x 10 −3 mm2/s respectively. Statistically no significant difference was seen in diseased and control group. Cut-off to detect neuropathy for FA and ADC is 0.4835 and 1.1020 × 10 −3 mm2/s respectively. Conclusion: DTI though is challenging in peripheral nerves, however, is proving to be a powerful complementary tool for assessment of peripheral neuropathy. Our study validates its utility in infective neuropathies. Advances in knowledge: 1. DTI is a potential complementary tool for detection of peripheral neuropathies and can be incorporated in standard MR neurography protocol. 2. In leprosy-related ulnar neuropathy, altered signal intensity with thickening or abscess of the nerve is appreciated along with locoregional nodes and secondary denervation changes along with reduction of FA and rise in ADC value. 3. Best cut-offs obtained in our study for FA and ADC are 0.4835 and 1.1020 × 10 −3 mm2/s respectively.

Role of superoxide anion in regulating pressor and vascular hypertrophic response to angiotensin II

2002 ◽  
Vol 282 (5) ◽  
pp. H1697-H1702 ◽  
Author(s):  
Hui Di Wang ◽  
Douglas G. Johns ◽  
Shanqin Xu ◽  
Richard A. Cohen
Keyword(s):  
Superoxide Anion ◽  
Pressor Response ◽  
Cross Sectional Area ◽  
Ang Ii ◽  
Sectional Area ◽  
Wild Type ◽  
Cross Sectional ◽  
Hypertrophic Response

Our purpose was to address the role of NAPDH oxidase-derived superoxide anion in the vascular response to ANG II. Blood pressure, aortic superoxide anion, 3-nitrotyrosine, and medial cross-sectional area were compared in wild-type mice and in mice that overexpress human superoxide dismutase (hSOD). The pressor response to ANG II was significantly less in hSOD mice. Superoxide anion levels were increased twofold in ANG II-treated wild-type mice but not in hSOD mice. 3-Nitrotyrosine increased in aortic endothelium and adventitia in wild-type but not hSOD mice. In contrast, aortic medial cross-sectional area increased 50% with ANG II in hSOD mice, comparable to wild-type mice. The lower pressor response to ANG II in the mice expressing hSOD is consistent with a pressor role of superoxide anion in wild-type mice, most likely because it reacts with nitric oxide. Despite preventing the increase in superoxide anion and 3-nitrotyrosine, the aortic hypertrophic response to ANG II in vivo was unaffected by hSOD.

The Role of the Paratenon in Achilles Tendon Healing: A Study in Rats

2018 ◽  
Vol 46 (5) ◽  
pp. 1214-1219 ◽  
Author(s):  
Sebastian A. Müller ◽  
Christopher H. Evans ◽  
Patricia E. Heisterbach ◽  
Martin Majewski
Keyword(s):  
Achilles Tendon ◽  
Tendon Healing ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Sprague Dawley ◽  
Cross Sectional ◽  
Collagen Formation ◽  
Tendon Defect ◽  
Tear Resistance

Background: The role of the paratenon in tendon healing is unknown. The present study compares healing in the presence or absence of the paratenon in an Achilles tendon defect model in rats. Hypothesis: Resection of the paratenon impairs tendon healing. Study Design: Controlled laboratory study. Methods: Sixty skeletally mature Sprague Dawley rats were randomly assigned to either a resected paratenon (RP) group or an intact paratenon (IP) group. In all animals, a 4-mm portion of the Achilles tendon was resected in the midsubstance. In the RP group, the paratenon was resected completely. In the IP group, the paratenon was opened longitudinally and closed again after the tendon defect had been created. One, 2, and 4 weeks after surgery, 7 animals per group were tested biomechanically and 3 animals per group examined histologically. Results: The recovery of mechanical strength was much more rapid in IP tendons. Tear resistance was significantly increased for IP tendons (41.3 ± 8.8 N and 47.3 ± 14.1 N, respectively) compared with RP tendons (19.3 ± 9.1 N and 33.2 ± 6.4 N, respectively) after 1 and 2 weeks. The cross-sectional area was larger in the IP group after 1 and 2 weeks (8.2 ± 2.3 mm2 and 11.3 ± 3.1 mm2 vs 5.0 ± 2.4 mm2 and 5.9 ± 2.0 mm2, respectively) compared with the RP group. Tendon stiffness was greater in the IP group after 1 week (10.4 ± 1.9 N/mm vs 4.5 ± 1.6 N/mm, respectively) compared with the RP group. In comparison, normal contralateral tendons had a maximal tear resistance of 56.6 ± 7.2 N, a cross-sectional area of 3.6 ± 0.7 mm2, and stiffness of 17.3 ± 3.8 N/mm. Hematoxylin and eosin staining revealed slightly delayed healing of RP tendons. Early collagen formation was seen in the IP group already after 1 week, whereas in the RP group, this only occurred after 2 weeks. After 4 weeks, the IP tendons showed more collagen crimp formation than the RP tendons. Conclusion: An intact paratenon promotes healing of the Achilles tendon. Clinical Relevance: Although incision or resection of the paratenon has been advocated when repairing injured or degenerative tendons, our data suggest that the integrity of the paratenon should be preserved.

Optimization Design of an Efficient Evacuator for Gun Barrels

2021 ◽  
Author(s):  
Quanzhao Sun ◽  
Li Chen ◽  
Jie Zhang ◽  
Yanming Song ◽  
Guolai Yang ◽  
...  
Keyword(s):  
Optimization Design ◽  
Structural Parameters ◽  
Cross Sectional Area ◽  
Main Function ◽  
Sectional Area ◽  
Working Process ◽  
Cross Sectional ◽  
Mathematical Expressions ◽  
Reliability Indicator ◽  
The Cross

Abstract Evacuators are key components of gun barrels, and their main function is to drain the gunpowder gas remaining in the gun bore from the muzzle by ejection. To design an efficient evacuator for the gun barrels, an optimization model with the mathematical expressions describing the working process of the evacuator was established. The four structural parameters that affect the efficiency of the evacuator, including the volume of the gas storage cylinder chamber, the distance of the nozzle from the muzzle end face, the cross-sectional area of the nozzles and the cross-sectional area of the valves, were optimized. The effective working time and reliability indicator of the optimized evacuator were improved. This work describes a framework for improving the design of highly efficient evacuators on gun barrels.

Role of Umbilical Cord Cross Sectional Area (UCCSA) in Prediction of Neonatal Birth Weight

2018 ◽  
Vol 6 (3) ◽  
pp. 301-308
Author(s):  
Sapna V. Amin ◽  
◽  
Deepika Pothakamuri ◽  
Prashant Adiga ◽  
Shripad Hebbar ◽  
...  
Keyword(s):  
Birth Weight ◽  
Umbilical Cord ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Neonatal Birth Weight

Abstract 72: Pka Is A Master Regulator Of Pathological Cardiac Hypertrophy

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Xiaoying Zhang ◽  
Ying LI ◽  
Mingxin Tang ◽  
Xiaojie Ai ◽  
Christopher Szeto ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Angiotensin Ii ◽  
Cardiac Hypertrophy ◽  
Surface Area ◽  
Myocardial Fibrosis ◽  
Pressure Overload ◽  
Sectional Area ◽  
Cross Sectional ◽  
Pathological Cardiac Hypertrophy

Aims: The role of PKA in pathological cardiac hypertrophy (PCH) is not clear. The literature suggests both prohypertrophic and antihypertrophic effects of PKA. Furthermore, there are endogenous PKA inhibitors, PKI, highly expressed in the heart to regulate PKA activity but their roles in PCH have not been studied. We aim to explore the role of PKI/PKA in PCH induced by isoproterenol, phenylephrine, angiotensin II and pressure overload. Methods and Results: 1. PKIα and PKIγ were highly expressed in the heart but only PKIα was reduced by transaortic banding (TAB); TAB induced a significant increase in cardiac PKA activity at 1 week post TAB. 2. Four transgenic mouse lines with high (HE), medium (ME), low (LE) and very low (VLE) expression of PKI-GFP were obtained with the inhibition of maximum PKA activity induced by 1μM cAMP by 95%, 57%, 20% and 10% in the cardiac homogenates; 3. In the VLE hearts, some myocytes were PKI-GFP+ and some were PKI-GFP-, GFP- LVMs had significantly larger surface area than GFP+ LVMs; 4. PKA inhibition by PKI-GFP abolished PCH induced by isoproterenol, phenylephrine, angiotensin II in HE mice; 5. TAB for 8 weeks did not change HW/BW, myocyte cross-sectional area and myocardial fibrosis in HE mice but induced significant increases in HW/BW, myocyte cross-sectional area, myocardial fibrosis and depressed cardiac fractional shortening in control mice. 6. In cultured neonatal rat ventricular myocytes, PKI-GFP prevented myocyte hypertrophy induced by isoproterenol (ISO), phenylephrine (PE) and angiotensin II, as evidenced by no significant increases in protein synthesis (protein/DNA ratio), myocyte surface area, sarcomere organization. 7. PKI-GFP in NRVMs prevented the translocation of NFAT3 and HDAC5 induced by ISO and PE and increased the secretion of antihypertrophic ANF at baseline; 8. TAB induced PKA-dependent phosphorylation of GSK-3α and GSK-3β, inactivating them to relieve their antihypertrophic effect and promote protein synthesis (increased phosphorylation of mTORC1, eIF-4EBP1, p70 S6K); PKA inhibition abolished these effects. Conclusions: PKA is regulated by PKI and is a master regulator of PCH induced by pressure overload.

scholarly journals Cell sensing and decision-making in confinement: The role of TRPM7 in a tug of war between hydraulic pressure and cross-sectional area

2019 ◽  
Vol 5 (7) ◽  
pp. eaaw7243 ◽  
Author(s):  
Runchen Zhao ◽  
Alexandros Afthinos ◽  
Tian Zhu ◽  
Panagiotis Mistriotis ◽  
Yizeng Li ◽  
...  
Keyword(s):  
Decision Making ◽  
Calcium Influx ◽  
Maximum Entropy Principle ◽  
Cross Sectional Area ◽  
Hydraulic Pressure ◽  
Sectional Area ◽  
Cortical Actin ◽  
Cross Sectional ◽  
Entropy Principle

How cells sense hydraulic pressure and make directional choices in confinement remains elusive. Using trifurcating Ψ-like microchannels of different hydraulic resistances and cross-sectional areas, we discovered that the TRPM7 ion channel is the critical mechanosensor, which directs decision-making of blebbing cells toward channels of lower hydraulic resistance irrespective of their cross-sectional areas. Hydraulic pressure–mediated TRPM7 activation triggers calcium influx and supports a thicker cortical actin meshwork containing an elevated density of myosin-IIA. Cortical actomyosin shields cells against external forces and preferentially directs cell entrance in low resistance channels. Inhibition of TRPM7 function or actomyosin contractility renders cells unable to sense different resistances and alters the decision-making pattern to cross-sectional area–based partition. Cell distribution in microchannels is captured by a mathematical model based on the maximum entropy principle using cortical actin as a key variable. This study demonstrates the unique role of TRPM7 in controlling decision-making and navigating migration in complex microenvironments.

Reversible changes in size of cell nuclei isolated from Amoeba proteus: Role of the cytoskeleton

2000 ◽  
Vol 78 (4) ◽  
pp. 487-494 ◽  
Author(s):  
Pawel Pomorski ◽  
Lucyna Grebecka ◽  
Andrzej Grebecki ◽  
Robert Makuch
Keyword(s):  
External Medium ◽  
Amoeba Proteus ◽  
Distilled Water ◽  
Sectional Area ◽  
Cell Nuclei ◽  
Cross Sectional ◽  
Isolated Nuclei ◽  
Rigor State ◽  
Osmotic Effects

Micrurgically isolated interphasal nuclei of Amoeba proteus, which preserve F-actin cytoskeletal shells on their surface, shrink after perfusion with imidazole buffer without ATP, and expand to about 200% of their cross-sectional area upon addition of pyrophosphate. These changes in size may be reproduced several times with the same nucleus. The shrunken nuclei are insensitive to the osmotic effects of sugars and distilled water, whereas the expanded ones react only to the distilled water, showing further swelling. The shrinking-expansion cycles are partially inhibited by cytochalasins. They are attributed to the state of actomyosin complex in the perinuclear cytoskeleton, which is supposed to be in the rigor state in the imidazole buffer without ATP, and to dissociate in the presence of pyrophosphate. Inflow of external medium to the nuclei during dissociation of the myosin from the perinuclear F-actin may be due to colloidal osmosis depending on other macromolecular components of the karyoplasm.Key words: Amoeba proteus, isolated nuclei, perinuclear cytoskeleton.

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