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Empirical Relations To Predict The Probable Percentage Of Reduction In Root Fillet Stress In Spur Gear With Circular Stress Relief Feature  [PDF]
PROF VIJAYKUMAR CHALWA, NAGESH KAMANNA, PRASAD NAYAK
International Journal of Innovative Research in Science, Engineering and Technology , 2013,
Abstract: This Work Presents The Possibilities Of Percentage Of Reduction In The Root Fillet Stress Of Spur Gear By Introducing Circular Stress Relieving Feature Of Various Sizes At Different Locations. Two Categories Of Systematic Analyses Are Carried Out Using Finite Element Model Of Spur Gear. In The First Category Of Analyses Emphasize Is Given To Determine The Maximum Root Fillet Stress Which Is Required As Reference To Determine The Stress Reduction Factor. In Addition To This, The Effect Of Number Of Teeth, Pressure Angle, And Basic Parameters Of Rack Cutter On Root Fillet Stress Is Investigated. In Second Category Which Is The Prime Focus Of This Work; The Effect Of Introducing Geometric Stress Relief Feature Is Carried Out. Circular Stress Relief Feature Of Different Size At Strategic Locations On A Spur Gear Tooth Are Introduced. This Reduces The Root Fillet Stress. The Magnitude Of The Load Shared By A Gear Tooth Depends On The Position Of The Point Of Contact Of Teeth Engagement Along The Line Of Action. It Also Depends On Contact Ratio. High Contact Ratio Gear Teeth Pairs Are Subjected Low Load In Comparison Low Contact Ratio Gear For Transmitting Same Amount Of Torque. A Tooth Is Released From The Load As Soon As It Disengages With The Mating Gear Tooth And It Is Taken By The Next Conjugate Tooth. Therefore The Gear Teeth Are Subjected Varying (Fatigue) Load. If A Gear Fails By Bending Fatigue, The Failure Is Catastrophic And Occurs With Little Or No Warnings. The Maximum Root Fillet Tensile Stress Is One Of The Key Factors Which Determine The Fatigue Life Of The Gear. Therefore The Magnitude Of The Maximum Value Of The Root Fillet Tensile Stress Can Be Treated As The Index Of Fatigue Life Of Gear. Even Slight Reduction In Root Fillet Stress Leads To A Large Increase In Fatigue Life Of The Gears Designed For The Stress Level Above Endurance Limit. This Type Of Design Consideration Is Very Common, Where Safety And Light Weight Are The Principal Design Criteria. Therefore For All The Reasons Cited Above, This Work Is Of More Practical Importance. The Program Is Coded In ANSYS Parametric Design Language (APDL). It Automates The Task Of Creation Of Model, Meshing, Applying Boundary Conditions, Choosing The Appropriate Density Of The Mesh Depending On The Stress Gradient. It Also Provides A Means For Defining The Diameter And Location Of The Circular Stress Relief Features.
Polarization of Astronomical Maser Radiation. IV. Circular Polarization Profiles  [PDF]
Moshe Elitzur
Physics , 1998, DOI: 10.1086/306076
Abstract: Profile comparison of the Stokes parameters $V$ and $I$ is a powerful tool for maser data analysis, providing the first direct methods for unambiguous determination of (1) the maser saturation stage, (2) the amplification optical depth and intrinsic Doppler width of unsaturated masers, and (3) the comparative magnitudes of Zeeman splitting and Doppler linewidth. Circular polarization recently detected in OH 1720 MHz emission from the Galactic center appears to provide the first direct evidence for maser saturation.
Nonradiative DKR processes: revisiting the theory. IV. On the controversy over a polaron state bound to an F center in alkali halides  [PDF]
Mladen Georgiev
Physics , 2007,
Abstract: We are commenting on an earlier hypothesis of polaron states bound to F centers in alkali halides. These states increasing the effective size of the color centers, they play an active role in concentration-dependent phenomena, such as the observed quenching of F center luminescence. Our record shows only one related study on NaBr and NaI which has also been aimed at checking the bound polaron hypothesis. Further studies of the concentration quenching in other alkali halide hosts whould eventually shine more light on the problem.
Off-center impurity in alkali halides: reorientation, electric polarization and pairing to F center. IV. Reorientational rate  [PDF]
G. Baldacchini,R. M. Montereali,U. M. Grassano,A. Scacco,P. Petrova,M. Mladenova,M. Ivanovich,M. Georgiev
Physics , 2007,
Abstract: This last Part IV is aimed at deriving relaxation rates (times) of an off-center Li+ impurity. We follow Christov's reaction rate method to define general rate equations in terms of the exact Mathieu eigenvalues, as well as of harmonic-oscillator eigenvalues approximating for the energy spectrum near the bottom of the reorientational wells. To calculate the rate in each particular case, we derive configurational tunneling probabilities by either Mathieu eigenfunctions or by harmonic oscillator eigenfunctions. The electron-transfer probability is calculated by generalizing Landau-Zener's method. Typical examples are considered and compared with experimental relaxation times in KCl:Li+.
Inhibition of Cytochrome P450 3A in Rat Liver by the Diorganotin (IV) Compound di-n-Butyl-di-(4-chlorobenzo-hydroxamato)tin (IV) and Its Probable Mechanism  [PDF]
Yunxia Zhang,Yunlan Li,Qingshan Li
Molecules , 2012, DOI: 10.3390/molecules170910994
Abstract: The specific aims of this study were to evaluate the inhibition effect on CYP3A of di-n-butyl-di-(4-chlorobenzohydroxamato)tin (IV) (DBDCT), a tin-based complex with high antitumor activity, and the probable mechanism(s) of this action. Adult male SD rats were treated separately with natural saline (NS), lipopolysaccharide (LPS, 5 mg/kg), DBDCT (1.25, 2.5 and 5.0 mg/kg) intraperitoneally for 2 days after induction of CYP3A with dexamethasone (DEX, 100 mg/kg) for 4 days. Western blot analysis and fluorescent quantitation PCR (FQ-PCR) were conducted to determine the changes in expression of CYP3A, PXR, CAR and RXR. The biological accumulation of DBDCT and total Sn were determined by high-performance liquid chromatography (HPLC) and atomic fluorescence spectrometry (AFS). CYP450 content and CYP3A activities were significantly inhibited (p < 0.05) in DBDCT-treated rats compared with the control group, as was the expression of CYP3A (p < 0.05) at both protein and mRNA levels. In DBDCT-treated groups, the expression of PXR protein and mRNA increased, while the expression of CAR decreased. The biological accumulation of DBDCT and Sn in rat livers treated with DBDCT was high. The accumulation of DBDCT and Sn due to the inhibition of CYP3A may be involved in the mechanism of toxicity of DBDCT in rat liver.
Structural dissection of alkaline-denatured pepsin  [PDF]
Yuji O. Kamatari,Christopher M. Dobson,Takashi Konno
Spectroscopy: An International Journal , 2004, DOI: 10.1155/2004/769354
Abstract: Pepsin, a gastric aspartic proteinase, is a zymogen?derived protein that undergoes irreversible alkaline denaturation at pH 6–7. Detailed knowledge of the structure of the alkaline?denatured state is an important step in understanding the mechanism of the formation of the active enzyme. It has been established in a number of studies that the alkaline?denatured state of pepsin (the IP state) is composed of a compact C?terminal lobe and a largely unstructured N?terminal lobe. In the present study, we have investigated the residual structure in the IP state in more detail, using limited proteolysis to isolate and characterize a tightly folded core region from this partially denatured pepsin. The isolated core region corresponds to the 141 C?terminal residues of the pepsin molecule, which in the fully native state forms one of the two lobes of the structure. A comparative study using NMR and CD spectroscopy has revealed, however, that the N?terminal lobe contributes a substantial amount of additional residual structure to the IP state of pepsin. CD spectra indicate in addition that significant non?native α-helical structure is present in the C?terminal lobe of the structure when the N?terminal lobe of pepsin is either unfolded or removed by proteolysis. This study demonstrates that the structure of pepsin in the IP state is significantly more complex than that of a fully folded C?terminal lobe connected to an unstructured N?terminal lobe. The “misfolding” in this state could inhibit the proper refolding of the protein when returned to conditions that stabilize the native state.
Phagocytosis by macrophages mediated by receptors for denatured proteins - dependence on tyrosine protein kinases
Hespanhol, M.R.;Mantovani, B.;
Brazilian Journal of Medical and Biological Research , 2002, DOI: 10.1590/S0100-879X2002000300015
Abstract: previous studies have demonstrated that some components of the leukocyte cell membrane, cr3 (mac-1, cd11b/cd18) and p150/95, are able to bind to denatured proteins. thus, it is of interest to know which effector functions of these cells can be triggered by these receptors when they interact with particles or surfaces covered with denatured proteins. in the present study we analyzed their possible role as mediators of phagocytosis of red cells covered with denatured bovine serum albumin (bsa) by mouse peritoneal macrophages. we observed that a) macrophages are able to recognize (bind to) these red cells, b) this interaction can be inhibited by denatured bsa in the fluid phase, c) there is no phagocytosis of these particles by normal macrophages, d) phagocytosis mediated by denatured bsa can be, however, effectively triggered in inflammatory macrophages induced by glycogen or in macrophages activated in vivo with lps, and e) this phagocytic capacity is strongly dependent on the activity of tyrosine protein kinases in its signal transduction pathway, as demonstrated by using three kinds of enzyme inhibitors (genistein, quercetin and herbimycin a).
Phagocytosis by macrophages mediated by receptors for denatured proteins - dependence on tyrosine protein kinases  [cached]
Hespanhol M.R.,Mantovani B.
Brazilian Journal of Medical and Biological Research , 2002,
Abstract: Previous studies have demonstrated that some components of the leukocyte cell membrane, CR3 (Mac-1, CD11b/CD18) and p150/95, are able to bind to denatured proteins. Thus, it is of interest to know which effector functions of these cells can be triggered by these receptors when they interact with particles or surfaces covered with denatured proteins. In the present study we analyzed their possible role as mediators of phagocytosis of red cells covered with denatured bovine serum albumin (BSA) by mouse peritoneal macrophages. We observed that a) macrophages are able to recognize (bind to) these red cells, b) this interaction can be inhibited by denatured BSA in the fluid phase, c) there is no phagocytosis of these particles by normal macrophages, d) phagocytosis mediated by denatured BSA can be, however, effectively triggered in inflammatory macrophages induced by glycogen or in macrophages activated in vivo with LPS, and e) this phagocytic capacity is strongly dependent on the activity of tyrosine protein kinases in its signal transduction pathway, as demonstrated by using three kinds of enzyme inhibitors (genistein, quercetin and herbimycin A).
Asymmetry in the shapes of folded and denatured states of proteins  [PDF]
Ruxandra I. Dima,D. Thirumalai
Quantitative Biology , 2003,
Abstract: The asymmetry in the shapes of folded and unfolded states are probed using two parameters, one being a measure of the sphericity and the other that describes the shape. For the folded states, whose interiors are densely packed, the radii of gyration (Rg) and these two parameters are calculated using the coordinates of the experimentally determined structures. Although Rg scales as expected for maximally compact structures, the distributions of the shape parameters show that there is considerable asymmetry in the shapes of folded structures. The degree of asymmetry is greater for proteins that form oligomers. Analysis of the two- and three-body contacts in the native structures shows that the presence of near equal number of contacts between backbone and side-chains and between side-chains gives rise to dense packing. We suggest that proteins with relatively large values of shape parameters can tolerate volume mutations without greatly affecting the network of contacts or their stability. To probe shape characteristics of denatured states we have developed a model of a WW-like domain. The shape parameters, which are calculated using Langevin simulations, change dramatically in the course of coil to globule transition. Comparison of the values of shape parameters between the globular state and the folded state of WW domain shows that both energetic (especially dispersion in the hydrophobic interactions) and steric effects are important in determining packing in proteins.
The Comparision of Denatured and non-denatured PAGE-Silver- Staining Detection of PCR Product of Microsatellites
微卫星PCR产物变性与非变性PAGE-银染检测方法的比较 The Comparision of Denatured and non-denatured PAGE–Silver- Staining Detection of PCR Product of Microsatellites

QU Lu-Jiang,LI Xian-Yao,DU Zhi-Qiang,ZHANG Long-Chao,YANG Ning,
曲鲁江
,李显耀,杜志强,张龙超,杨宁

遗传 , 2004,
Abstract: The genomic DNAs from six chicken breeds in China were amplified using two microsatellite primers. The PCR products were detected by non-denatured and denatured PAGE gels respectively, and the gels were dyed by silver. There were distinct differences between the two kinds of gel. In non-denatured gels. There were many nonspecific bands while clear purposed bands were showed in denatured gels.
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