The Cutting Mechanism of Fine-Grain Abrasive Stone

The depth of cut for the individual abrasive grains and the cutting resistance affecting the individual cutting points that are produced in honing or superfinishing operations are important factors to investigate the cutting mechanism of fine-grain abrasive stone. But the above factors depend on the number of cutting points on the stone surface which comes in contact with the work surface. In this paper, the contact mechanism between the stone and the work surface has been investigated theoretically in order to determine the number of cutting points. And the number of cutting points is obtained as a function of the roughness of the stone surface, the pressure on the stone and the hardness of the work material. Then, for checking the validity of this theory, the mean depth of cut (tₘ)ₜₕ derived from the theoretical investigation of the contact mechanism is compared with the mean depth of cut (tₘ)ₑₓ which can be obtained from the stock removal per unit time and the number of cutting points on the stone surface in an actual superfinishing operation. As a result of this comparison, the validity of the theoretical equation for the number of cutting points was established by inquiring into the causes of the difference between (tₘ)ₜₕ and (tₘ)ₑₓ and their influence on the number of cutting points

Research on the Cutting Performance of Fine-Grain Abrasive Stone

For the purpose of improving cutting performance of fine-grain abrasive stones, the authors investigated about numerous fine-grain abrasive stones of various bond hardness, bond combining ratio, porosity and grain combining ratio, using a special testing apparatus with which stone wear, stock removal and cutting resistance could be measured, and obtained the following results. The results of the model performance test obtained with the testing apparatus designed by the authors coincide well with the results of practical superfinishing. The porosity is the most decisive factor on cutting performance among the constitutional factors of a fine-grain abrasive stone. In order to get a good cutting performance, it is necessary to use stones which maintain higher bond hardness with smaller quantity of bond and have larger porosity

Fundamental Research of the Superfinish

On the various work materials, the most suitable condition of cutting motion in the superfinish, and the relation of the abrasive stone pressure and cutting direction angle to the characteristics of superfinished surface have been investigated. As to the speed of cutting, it was found that the higher the speed, the better the efficiency provided the speed is kept within the range in which harmful vibrations of superfinishing machine bed is not produced, and as to the cutting direction angle, 40°～60° to be most efficient. In addition, the characteristics of superfinishing_ process may be classified into “cutting”, “semi-cutting” and “mirror-finishing” according to the values of stone pressure and cutting direction angle, and the most efficient cutting condition has been found on the boundary line of “cutting” and “semi-cutting”

Fundamental Research on Gear Lubrication

In this paper, the fundamental characteristics of gear lubrication were synthetically clarified, and the oil-film formation between mating gear-teeth was investigated, taking into consideration the dynamic performance of gear-teeth. Using roller and gear testing equipments, the fundamental lubrication characteristics were measured under various driving conditions, and the lubrication characteristic was classified into three regions. The correlation between both lubrication characteristics of rollers and gears was investigated referring to the experimental results, and it is deduced that the analysis of the dynamic phenomena owing to gear mating is very important. The transient characteristics of oil-film due to the gear-mesh were theoretically analyzed, and the transient performance of oil-film was experimentally measured using special models of rollers. The dynamic lubrication theory was applied to the practical gears in consideration of the tooth deflection, and the variation of oil-film thickness was measured through over-all range of a geartooth mesh using a special test gears. From these results, the principle of oil-film formation in gears were discussed

Role of KIT-Positive Interstitial Cells of Cajal in the Urinary Bladder and Possible Therapeutic Target for Overactive Bladder

In the gastrointestinal tract, interstitial cells of Cajal (ICCs) act as pacemaker cells to generate slow wave activity. Interstitial cells that resemble ICCs in the gastrointestinal tract have been identified by their morphological characteristics in the bladder. KIT is used as an identification marker of ICCs. ICCs in the bladder may be involved in signal transmission between smooth muscle bundles, from efferent nerves to smooth muscles, and from the urothelium to afferent nerves. Recent research has suggested that not only the disturbance of spontaneous contractility caused by altered detrusor ICC signal transduction between nerves and smooth muscle cells but also the disturbance of signal transduction between urothelial cells and sensory nerves via suburothelial ICC may induce overactive bladder (OAB). Recent reports have suggested that KIT is not only a detection marker of these cells, but also may play a crucial role in the control of bladder function. Research into the effect of a c-kit receptor inhibitor, imatinib mesylate, on bladder function implies that KIT-positive ICCs may be therapeutic target cells to reduce bladder overactivity and that the blockage of c-kit receptor may offer a new therapeutic strategy for OAB treatment, although further study will be needed

Cloning of cDNAs for the Precursor Protein of a Low-Molecular-Weight Subunit of the Inner Layer of the Egg Envelope (Chorion) of the Fish Oryzias latipes

AbstractcDNA clones for L-SF, the precursor of a low-molecular-weight subunit (ZI-3) of the inner layer of the Oryzias latipes egg envelope were isolated from Lambda ZAP cDNA libraries constructed from the poly(A)+ RNA of the liver of spawning female fish and estrogen-treated male fish. Among them, a clone, L-SF41, is 1473 bp long and contains an open reading frame encoding a signal peptide of 19 amino acids and L-SF protein of 420 amino acids. L-SF protein seems to be glycosylated, judging from the result of the glycanase digestion. L-SF protein contains a domain similar to ZP-domains in ZP3 of some mammalian species. Northern blot analysis employing XhoI-SmaI fragments of the cloned cDNA as probes revealed that expression of the L-SF gene occurred exclusively in the livers of spawning female fish and estrogen-treated male fish and that there was no mRNA encoding L-SF in the ovary of the spawning female fish

Uric acid-lowering and renoprotective effects of topiroxostat, a selective xanthine oxidoreductase inhibitor, in patients with diabetic nephropathy and hyperuricemia: a randomized, double-blind, placebo-controlled, parallel-group study (UPWARD study)

金沢大学医薬保健研究域医学系Background: Hyperuricemia is supposed to be an independent risk factor for kidney dysfunction in diabetic patients. We attempted to examine the uric acid-lowering effect and the renoprotective effect of topiroxostat, a selective xanthine oxidoreductase inhibitor, in patients with diabetic nephropathy and hyperuricemia in this pilot study. Methods: The study design was randomized, double-blind, placebo-controlled, parallel-group study. A total of 65 patients with hyperuricemia and diabetic nephropathy with microalbuminuria were enrolled and assigned to either the topiroxostat group or the placebo group. Topiroxostat (stepwise dosing from 40 to 160 mg/day) or matching placebo was administered BID for 28 weeks. The primary endpoint was a change in the urinary albumin-to-creatinine ratio in the first-morning-void urine sample. Secondary endpoints were changes in the estimated glomerular filtration rate and the serum uric acid level. Results: At 28 weeks, there was no significant difference in the percent change from baseline in the urinary albumin-to-creatinine ratio between the two groups (topiroxostat: 0 vs. placebo: 17%, p = 0.3206), but the changes in the estimated glomerular filtration rate (− 0.2 vs. − 4.0 mL/min/1.73 m2, p = 0.0303) and the serum uric acid level (− 2.94 vs. − 0.20 mg/dL, p < 0.0001) were significantly different between the topiroxostat and placebo groups. Gouty arthritis occurred in 1 patient in the placebo group and no patients in the topiroxostat group. Conclusion: These findings support that diabetic nephropathy combined with hyperuricemia may be associated with kidney dysfunctions. Topiroxostat provides strict control of the serum uric acid level preventing decline of eGFR in these patients. © 2018 The Author(s)Embargo Period 12 month

Acetyl-L-carnitine suppresses thyroid hormone-induced and spontaneous anuran tadpole tail shortening

Mitochondrial membrane permeability transition (MPT) plays a crucial role in apoptotic tail shortening during anuran metamor phosis. L-carnitine is known to shuttle free fatty acids (FFAs) from the cytosol into mitochondria matrix for -oxidation and energy production, and in a previous study we found that treatment with L-carnitine suppresses 3, 3', 5-triiodothyronine (T3) and FFA-induced MPT by reducing the level of FFAs. In the present study we focus on acetyl-L-carnitine, which is also involved in fatty acid oxidation, to determine its effect on T3-induced tail regression in Rana rugosa tadpoles and spontaneous tail regression in Xenopus laevis tadpoles. The ladder-like DNA profile and increases in caspase-3 and caspase-9 indicative of apoptosis in the tails of T3-treated tadpoles were found to be suppressed by the addition of acetyl-L-carnitine. Likewise, acetyl-L-carnitine was found to inhibit thyroid hormone regulated spontaneous metamorphosis in X. laevis tadpoles, accompanied by decreases in caspase and phospholipase A2 activity, as well as non-ladder-like DNA profiles. These findings support our previous conclusion that elevated levels of FFAs initiate MPT and activate the signaling pathway controlling apoptotic cell death in tadpole tails during anuran metamorphosis