Re-evaluation of Metaplastic Osteogenesis in the Bovine Lymph Node with Metastatic Cholangiocarcinoma: A Supplemental Report

Introduction: For deepening knowledge of the developmental process involving metaplastic osteogenesis in extraskeletal tumor, histopathological re-evaluation was conducted on osseous metaplasia in the bovine lymph node with metastatic cholangiocarcinoma, which was previously reported in this journal by the author.Presentation of Case: In an aged Holstein-Friesian dairy cow that exhibited intrahepatic cholangiocarcinoma with widespread metastasis, a mesenteric lymph node with metastatic cancer had multifocal areas of osseous metaplasia. Abundant stromal connective tissue of the metastatic cancer showed prominent proliferation of capillaries and mesenchymal cells. There were no definite transitional features between mesenchymal cells associated with bone tissue and cancer cells. A variety of stages toward differentiating into osseous component included occurrence of (1) focal areas of dense collagen fibers accompanied by many mesenchymal cells, (2) osteoid surrounded by a single to multilayer of osteoblasts, (3) trabeculae of woven bone containing many osteocytes, and (4) bone resorption associated with osteoclastic activity in more differentiated bone trabeculae. These findings suggested that osseous metaplasia might have developed through the process identical to intramembranous ossification, as seen in flat bone formation in the developing fetus. Furthermore, this metaplastic osteogenesis was associated with the process involving the coordinated activities of osteoblasts and osteoclasts, as seen in remodeling of bone tissue throughout postnatal life.Conclusion: Although metaplastic bone did not fully differentiated into mature bone, the pathway of metaplastic osteogenesis might have followed the developmental stages identical, to some degree, to the process that controls skeletal maturation and remodeling.

Nanolayered Diamond Sintered Compact Obtained by Direct Conversion from Highly Oriented Graphite under High Pressure and High Temperature

A new type of polycrystalline sintered diamond has been successfully synthesized by direct conversion from highly oriented pyrolytic graphite at 15 GPa and 2300°C. It is optically transparent and consists entirely of layered nanocrystals (50–100 nm thick) of cubic diamond, which are tightly bound to each other and have strong [111] preferred orientation along the stacking direction. This nanolayered diamond has excellent indentation hardness (~114 GPa in Knoop scale) comparable to the highest values obtained from single crystalline diamond. Furthermore, it is expected to have significantly high wear resistance on both ends of cylindrical sintered compact, since the surfaces are terminated exclusively by the hardest {111} planes of the layered diamond nanocrystals

Wear resistance of nano-polycrystalline diamond with various hexagonal diamond contents

Wear resistance of nano-polycrystalline diamond (NPD) rods containing various amounts of hexagonal diamond has been tested with a new method for practical evaluation of the wear–resistance rate of superhard ceramics, in addition to the measurements of their Knoop hardness. The wear resistance of NPD has been found to increase with increasing synthesis temperature and accordingly decreasing proportion of hexagonal diamond. A slight increase in Knoop hardness with the synthesis temperature also has been observed for these samples, consistent with the results of the wear–resistance measurements. These results suggest that the presence of hexagonal diamond would not yield any observable increase in both hardness and wear resistance of NPD, contradictory to a recent prediction suggesting that hexagonal diamond is harder than cubic diamond. It is also demonstrated that NPD is superior to single crystal diamond in terms of relatively homogeneous wearing without any significant chipping/cracking.Зносостійкість нано-полікристалічних алмазних (НПА) стрижнів, з різним вмістом гексагонального алмазу, була протестована новим методом практичної оцінки швидкості зносу надтвердої кераміки, додатково до вимірюваня їх твердості по Кнупу. Було виявлено, що зносостійкість НПА збільшується зі зростанням температури синтезу і, відповідно, зі зменшенням частки гексагональних алмазів. Також, відповідно до результатів вимірювань зносостійкості, для цих зразків спостерігалося невелике збільшення твердості по Кнупу з температурою синтезу. Ці результати дозволяють припустити, що присутність гексагональних алмазів не приводить до будь-якого помітного збільшення як твердості, так і зносостійкості НПА, що суперечить недавньому припущенню про те, що гексагональний алмаз твердіший, ніж кубічний. Також показано, що НПА перевершує монокристал алмазу з точки зору відносно однорідного зношування без значних відколів/тріщин.Износостойкость нано-поликристаллических алмазных (НПА) стержней, с различным содержанием гексагонального алмаза, была протестирована новым методом практической оценки скорости износа сверхтвердой керамики, в дополнение к измерениям их твердости по Кнупу. Было обнаружено, что износостойкость НПА увеличивается с ростом температуры синтеза и, соответственно, с уменьшением доли гексагональных алмазов. Также, в соответствии с результатами измерений износостойкости, для этих образцов наблюдалось небольшое увеличение твердости по Кнупу с температурой синтеза. Эти результаты позволяют предположить, что присутствие гексагональных алмазов не приводит к какому-либо заметному увеличению как твердости, так и износостойкости НПА, что противоречит недавнему предположению о том, что гексагональный алмаз тверже, чем кубический. Также показано, что НПА превосходит монокристалл алмаза с точки зрения относительно однородного изнашивания без значительных сколов/трещин

The investigation of back-transformation mechanisms of ringwoodite and majorite in the Yamato 75267 H6

The Tenth Symposium on Polar Science/Special session: [OA] Antarctic meteorites, Thur. 5 Dec. / 3F Multipurpose conference room, National Institute of Polar Researc

Micromagnetic simulations of first-order reversal curve (FORC) diagrams of framboidal greigite

Greigite is a sensitive environmental indicator and occurs commonly in nature as magnetostatically interacting framboids. Until now only the magnetic response of isolated non-interacting greigite particles have been modelled micromagnetically. We present here hysteresis and first-order reversal curve (FORC) simulations for framboidal greigite (Fe3S4), and compare results to those for isolated particles of a similar size. We demonstrate that these magnetostatic interactions alter significantly the framboid FORC response compared to isolated particles, which makes the magnetic response similar to that of much larger (multidomain) grains. We also demonstrate that framboidal signals plot in different regions of a FORC diagram, which facilitates differentiation between framboidal and isolated grain signals. Given that large greigite crystals are rarely observed in microscopy studies of natural samples, we suggest that identification of multidomain-like FORC signals in samples known to contain abundant greigite could be interpreted as evidence for framboidal greigite

Nanoparticulate nickel sulfides formed in low temperature aqueous solutions

The nature of the nickel sulfides formed in low temperature aqueous solutions is not well-understood. The material has some intrinsic interest to mineralogy, geochemistry and materials science as well as to biogeochemisty, especially as a possible catalyst involved in the origin and early evolution of life. We synthesized Ni sulfide under anoxic conditions at 25 C: (1) chemically, by the addition of 50 mL of 0.1 M NiSO4Æ7H2O to 100 mL of 0.05M Na2SÆ9H2O; (2) electrochemically, with a Ni foil and H2S gas. At pH 6 5, millerite (b-NiS) was produced electrochemically and NiS mixtures, including heazlewoodite (Ni3S2) and polydymite (Ni3S4), were obtained chemically. At pH >11, a- NiS was obtained from the chemical reaction. At pH 6–9, the product produced only two broad peaks (d = ca. 2.7 and 1.8 ) with conventional and synchrotron XRPD which could be assigned to a number of Ni sulfides. It has previously been referred to as ‘‘amorphous NiS’’ Jeong and Manthiram, 2001. Eight SAED reflections were collected which identified the material as godlevskite, orthorhombic NiS. HRTEM shows that the godlevskite particles are ca. 30 nm in diameter and plate-like. SAXS analyses show that the material is 6–8.5 nm thick. Godlevskite is structurally related to makinawite, tetragonal FeS, and is found naturally in similar parageneses-associated with the monosulfide solid solution products of high temperature nickel ores. Mackinawite is the black FeS precipitate from the reaction between Fe(II) and S(-II) in aqueous solution. It appears that, geochemically, godlevskite is the Ni analogue of mackinawite

Nucleation mechanism for the direct graphite-to-diamond phase transition

Graphite and diamond have comparable free energies, yet forming diamond from graphite is far from easy. In the absence of a catalyst, pressures that are significantly higher than the equilibrium coexistence pressures are required to induce the graphite-to-diamond transition. Furthermore, the formation of the metastable hexagonal polymorph of diamond instead of the more stable cubic diamond is favored at lower temperatures. The concerted mechanism suggested in previous theoretical studies cannot explain these phenomena. Using an ab initio quality neural-network potential we performed a large-scale study of the graphite-to-diamond transition assuming that it occurs via nucleation. The nucleation mechanism accounts for the observed phenomenology and reveals its microscopic origins. We demonstrated that the large lattice distortions that accompany the formation of the diamond nuclei inhibit the phase transition at low pressure and direct it towards the hexagonal diamond phase at higher pressure. The nucleation mechanism proposed in this work is an important step towards a better understanding of structural transformations in a wide range of complex systems such as amorphous carbon and carbon nanomaterials