Microgravity effects on nonequilibrium melt processing of neodymium titanate: thermophysical properties, atomic structure, glass formation and crystallization

The relationships between materials processing and structure can vary between terrestrial and reduced gravity environments. As one case study, we compare the nonequilibrium melt processing of a rare-earth titanate, nominally 83TiO2-17Nd2O3, and the structure of its glassy and crystalline products. Density and thermal expansion for the liquid, supercooled liquid, and glass are measured over 300-1850 °C using the Electrostatic Levitation Furnace (ELF) in microgravity, and two replicate density measurements were reproducible to within 0.4%. Cooling rates in ELF are 40-110 °C s-1 lower than those in a terrestrial aerodynamic levitator due to the absence of forced convection. X-ray/neutron total scattering and Raman spectroscopy indicate that glasses processed on Earth and in microgravity exhibit similar atomic structures, with only subtle differences that are consistent with compositional variations of ~2 mol. % Nd2O3. The glass atomic network contains a mixture of corner- and edge-sharing Ti-O polyhedra, and the fraction of edge-sharing arrangements decreases with increasing Nd2O3 content. X-ray tomography and electron microscopy of crystalline products reveal substantial differences in microstructure, grain size, and crystalline phases, which arise from differences in the melt processes.

Atomic and Electronic Structure in MgO-SiO2

Understanding disordered structure is difficult due to insufficient information in experimental data. Here, we overcome this issue by using a combination of diffraction and simulation to investigate oxygen packing and network topology in glassy (g-) and liquid (l-) MgO-SiO2 based on a comparison with the crystalline topology. We find that packing of oxygen atoms in Mg2SiO4 is larger than that in MgSiO3, and that of the glasses is larger than that of the liquids. Moreover, topological analysis suggests that topological similarity between crystalline (c)- and g-(l-) Mg2SiO4 is the signature of low glass-forming ability (GFA), and high GFA g-(l-) MgSiO3 shows a unique glass topology, which is different from c-MgSiO3. We also find that the lowest unoccupied molecular orbital (LUMO) is a free electron-like state at a void site of magnesium atom arising from decreased oxygen coordination, which is far away from crystalline oxides in which LUMO is occupied by oxygen's 3s orbital state in g- and l-MgO-SiO2, suggesting that electronic structure does not play an important role to determine GFA. We finally concluded the GFA of MgO-SiO2 binary is dominated by the atomic structure in terms of network topology.

Uncertainty analysis and performance evaluation of thermophysical property measurement of liquid Au in microgravity

A new method for quantifying facility performance has been discussed in this study that encompasses uncertainties associated with thermophysical property measurement. Four key thermophysical properties: density, volumetric thermal expansion coefficient, surface tension, and viscosity of liquid Au have been measured in microgravity environment using two different levitation facilities. Levitation experiments were conducted using the Electrostatic Levitation Furnace (ELF) onboard the ISS in Argon and air, and the TEMPUS Electromagnetic Levitation (EML) facility on a Novespace Zero-G aircraft parabolic flight in Argon. The traditional Maximum Amplitude method was augmented through the use of Frequency Crossover method to identify the natural frequency for oscillations induced on a molten sample during Faraday forcing in ESL. The EML tests were conducted using a pulse excitation method where two techniques, one imaging and one non-imaging, were used to study surface oscillations. The results from both facilities are in excellent agreement with the published literature values. A detailed study of the accuracy and precision of the measured values has also been presented in this work to evaluate facility performance.

High-dose zoledronic acid narrows the periodontal space in rats

The aim of this experiment was to evaluate the histological effects of zoledronic acid on the periodontal space in rats. 40 male Wistar rats were divided into three zoledronic acid groups and a control group. Zoledronic acid was injected subcutaneously at doses of 10, 50, or 500 μg/kg once a week for 3 weeks. The rats were killed 1 or 9 weeks after the last injection. Histological examination of the periodontal space around the incisor tooth revealed that zoledronic acid did not inhibit tooth development. In the rats killed 1 week after treatment discontinuation, the periodontal space gradually narrowed in response to increasing zoledronic acid doses, and the changes were statistically significant according to ANOVA but not according to ANOVA with post hoc tests. The changes persisted in the high-dose zoledronic acid group despite zoledronic acid discontinuation, with significant differences identified by ANOVA and ANOVA with post hoc tests. Therefore, although zoledronic acid had an insignificant effect on tooth development, it had a significant effect on the periodontal space when high doses were administered. The results of this experiment may provide useful information for future investigations on the role of zoledronic acid in the osteonecrosis of the jaw.

Enhanced protein levels of protein thiol/disulphide oxidoreductases in placentae from pre-eclamptic subjects

Recent studies have indicated that pre-eclampsia is closely associated with oxidative stress both in maternal circulation and in the placenta. Protein thiol/disulphide oxidoreductases, such as thioredoxin, glutaredoxin, and protein disulphide isomerase have recently been found to eliminate reactive oxygen species (ROS) and regenerate oxidatively damaged proteins. Protein thiol/disulphide oxidoreductases may also play a role in combating pre-eclampsia. In this study, we examined the accumulation of 4-hydroxy-2-nonenal (HNE)-modified proteins, which are markers of lipid peroxidation, in human placentae of normal and pre-eclamptic subjects. We also examined the protein levels of thioredoxin, glutaredoxin, and protein disulphide isomerase in placentae. Immunoblotting and immunohistochemistry showed that HNE-modified proteins accumulated to a greater extent in pre-eclamptic placentae than in normal placentae. In both normal and pre-eclamptic placentae, thioredoxin, glutaredoxin, and protein disulphide isomerase were detected in the trophoblasts of the floating villi. The levels of these proteins were increased approximately 2- to 3-fold in the pre-eclamptic placentae compared to the normal placentae. These results indicated that the pre-eclamptic placentae were exposed to oxidative stress and that the protein thiol/disulphide oxidoreductases were adaptively induced in pre-eclamptic placentae, suggesting possible roles for thioredoxin, glutaredoxin, and protein disulphide isomerase in protecting placental functions against oxidative stress caused by pre-eclampsia.

Myxoid leiomyosarcoma of the uterus. Report of a case with cytologic findings

BACKGROUND

Myxoid leiomyosarcoma is a rare variant of uterine sarcoma, exhibiting malignant biologic behavior despite the absence of cytologic atypia and of significant mitotic activity.

CASE

A 20-year-old female was referred with a cystic pelvic mass. At laparotomy, the tumor, weighed 2,200 g and originating in the left lateral uterine wall, was removed. Microscopic examination revealed well-differentiated smooth muscle cells without atypia and with a few mitotic figures in the copious myxoid matrix, suggesting myxoid leiomyosarcoma. Three years following laparotomy, an irregular mass around the uterus was noted on sonographic examination, suggesting local recurrence. Two years and six months later, the second operation was performed, and a locally recurrent, multicystic tumor weighing 3,500 g was excised. The histopathology was similar to that of the primary tumor. Cytologic findings on imprint material from the tumor revealed a few isolated or sheet like small cells consisting of spindle and polygonal cells with round and oval nuclei. Cytologic atypia was also minimal.

CONCLUSION

Myxoid leiomyosarcoma should be included in the differential diagnosis of smooth muscle neoplasia.

Pituitary folliculo-stellate-like cell line (TtT/GF) responds to novel hypophysiotropic peptide (pituitary adenylate cyclase-activating peptide), showing increased adenosine 3',5'-monophosphate and interleukin-6 secretion and cell proliferation

Several studies have shown that folliculo-stellate cells (FS cells) in the anterior pituitary gland exhibit paracrine functions. Recently, we established a pituitary FS-like cell line, TtT/GF, which was derived from an isologously transplantable pituitary thyrotropic tumor line induced by radiothyroidectomy. In studies to examine the function of FS cells, we found that two forms of a novel hypophysiotropic peptide, pituitary adenylate cyclase-activating polypeptide (PACAP), were potent activators of TtT/GF cells. Both the 27- and 38-amino acid forms of PACAP (PACAP-27 and PACAP-38) and vasoactive intestinal peptide (VIP) increased the levels of cAMP in TtT/GF cells in a similar dose-dependent manner. PACAP-27 and PACAP-38 specifically stimulated the proliferation of TtT/GF cells dose dependently, whereas VIP was ineffective. The minimal effective concentration of the PACAPs inducing cell proliferation was between 10(-8)-10(-7) M. However, PACAP-27 was much less potent than PACAP-38 in stimulating cell proliferation and DNA synthesis. PACAP-38, PACAP-27, and VIP all stimulated the release of interleukin-6 (IL-6) from TtT/GF cells. PACAP 38 (10(-8) M) stimulated IL-6 production effectively within 1 h of incubation, and the level attained at 8 h of cultivation (620 pg/ml) was nearly 10-fold that in the absence of PACAP-38 (60 pg/ml). PACAP-38 and VIP stimulated IL-6 secretion significantly at 10(-10)-10(-9) M in a bell-shaped manner; the maximum values were 10(-7) and 10(-8) M, respectively. On the other hand, IL-6 secretion stimulated by PACAP-27 became saturated at 10(-8) M, and the maximum value (320 pg/ml) was about 25% of that stimulated by PACAP-38 (1280 pg/ml). These findings obtained using TtT/GF cells as a model of FS cells suggest that PACAP acts as a hypophysiotropic factor, which targets FS cells and stimulates their proliferation, adenylate cyclase activation, and IL-6 secretion.

Newly established murine pituitary folliculo-stellate-like cell line (TtT/GF) secretes potent pituitary glandular cell survival factors, one of which corresponds to metalloproteinase inhibitor

A mouse folliculo-stellate cell (FS cell) line, TtT/GF, was found to secrete a potent survival factor influencing a somatotropic cell line (MtT/S) in serum-free medium. A three-step chromatography purification procedure using heparin-affinity chromatography, anion-exchange chromatography and gel-filtration chromatography revealed that the factor was a 27 kDa protein. Amino-terminal sequence analysis showed that the N-terminal 20 amino acids of the 27 kDa protein corresponded to those of human tissue inhibitor of metalloproteinase-II (TIMP-II). These results indicate that FS cells secrete TIMP-II, which probably protects the composition of the extracellular matrix and acts as a cell survival factor for endocrine cells in the anterior pituitary gland.

Establishment of a folliculo-stellate-like cell line from a murine thyrotropic pituitary tumor

An isologously transplantable mouse thyrotropic pituitary tumor (TtTb) that had been induced by radiothyroidectomy was found to form lobules composed of parenchymal glandular cell elements. The surfaces of these lobules were covered by stellate cells bearing long processes that gave a strong immunopositive reaction with a specific antiserum against glial fibrillary acidic protein (GFAP). GFAP was also positive in pituitary folliculo-stellate cells (FS cells). Since in the anterior pituitary gland, no other cellular component showing positive staining with anti-GFAP antibody was observed, it seems probable that the GFAP-positive cells in the thyrotropic tumor are related to the FS cells in the anterior pituitary. Upon cultivation of the thyrotropic tumor, cells with long processes appeared. These cells showed strong staining for GFAP and were dependent on basic fibroblast growth factor for cell growth. By repeated passage, the GFAP-positive cells became a stably growing immortal cell line, which was tentatively named TtT/GF. Since the characteristics of TtT/GF were similar to those of FS cells in the anterior pituitary, i.e. the presence of many lysosomes and numerous intermediate filaments in the cytoplasm, phagocytic activity, follicle formation, and GFAP and S-100 protein positivity, we suggest that TtT/GF cells are derived from pituitary FS cells.

[Controversial aspects in traumatic lesions of the pancreas]

The pancreatic anatomo-functional characteristics explain the traumatic gravidity and the problems in diagnostic. Its lesion is treated surgically, with controversial aspects. In terms of literature and analytic description of a case, were established: the initial course of trauma can be uncharacteristic, with normal amilasemia and abdomen Rx; the ultrasonography can determine the diagnosis; in cases of proximal transection of pancreas, the surgical treatment can include pancreatic derivation, in early operations, under favourable conditions.

Effects of cimetidine on lidocaine distribution in rats

The effects of cimetidine on the disappearance from plasma, plasma protein binding, tissue distribution, tissue binding in vitro and uptake by erythrocytes of lidocaine were studied in rats. The plasma disappearance of lidocaine after a 10 mg/kg bolus injection was analyzed by a two-compartment open model. In the cimetidine-treated rats (50 mg/kg bolus injection, the plasma total body clearance (Cltot), the volume of distribution at the steady state (Vdss) and the elimination rate constant of the central compartment (kel) of lidocaine decreased by 27, 28 and 32% of those of the non-treated rats, respectively. The plasma concentration of lidocaine at the steady state, after a loading dose (7.62 mg/kg body weight) followed by an infusion (0.16 mg/min/kg), increased from 1.62 to 2.69 micrograms/ml after cimetidine treatment. The tissue-to-plasma concentration ratio (Kp) in spleen, stomach and skin decreased to 64, 62 and 62% of the values of the non-treated rats. In addition, the blood-to-plasma concentration ratio (Rb) decreased by 26% in cimetidine-treated rats. In vitro tissue-to-plasma concentration ratios (Kp, vitro) of lidocaine in spleen, stomach and skin homogenate were decreased to 58, 45 and 68% by cimetidine treatment. In these tissues, the percentage decreases of Kp, vitro agreed with those of Kp determined in vivo. The decrease of Kp by cimetidine treatment may be due to the inhibition of tissue binding of lidocaine. The uptake of lidocaine by erythrocytes was decreased by cimetidine treatment.(ABSTRACT TRUNCATED AT 250 WORDS)