Heterogeneity of Crystals Attached to the Human Enamel and Cementum Surfaces After Calculus Removal In Vitro

Twenty one extracted human teeth with dental calculi on the enamel and cementum surfaces, fixed in 10% neutral formaldehyde, were selected for this study. After ethanol dehydration and air drying, these calculi were removed by tweezers to observe the teeth surfaces under them. The inspection of these surfaces using SEM and EDX revealed hexahedrally based crystals including pseudocuboidal, rhombohedral and variable rugged rocky shapes. These crystals were identified as Mg-containing whitlockite. The pseudocuboidal crystals, measuring about 4.5 μmin maximum length, were widely distributed on the cervical enamel surface previously covered by calculus. On the root surface, however, these areas decreased remakably; the shapes c hanged from pseudocubes into rhombohedrons and rugged rocky structures, while their sizes were smaller and the Mg content decreased. The difference in frequency and morphological variation of the hexahedrally based crystals might be caused by the different characteristics of enamel and cementum surfaces and the Mg present on these surfaces

Scanning Electron Microscopy and Energy-Dispersive X-Ray Microanalysis Studies of Early Dental Calculus on Resin Plates Exposed to Human Oral Cavities

Dental calculus formed after 10 days on resin plates, applied to the lingual sides of the mandibular gingival regions in eight human subjects, was investigated by means of scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDX). The mineral deposits were mainly divided into three types: A, B, and C. The type A deposits showing an average Ca/P molar ratio of 1.42 were densely packed with fine needle-shaped crystals formed by the intra- and extracellular calcification. The type A deposits, probably composed of Ca-deficient apatites and the transitional forms between apatite and octacalcium phosphate (OCP), were observed in all subjects. The type B deposits showing an average Ca/P molar ratio of 0.96 were aggregated with polygonal column, triangular plate-shaped, and rhombohedral crystals. These crystals identified as brushite (CaHPO4-2H2O: dicalcium phosphate dihydrate: DCPD) were found in four subjects. Platelet-shaped crystals of the type C deposits were observed in three subjects. Their Ca/P molar ratio of 1.26 and the crystal shape were similar to those of OCP. Whitlockite crystals were not found although Mg-containing hexagonal disk-like crystals were observed in two subjects

Fine Structure of the Inner Enamel in Human Permanent Teeth

Using SEM after EDTA etching, the mid-coronal inner enamel of human permanent teeth was classified into three regions of the 1st, 2nd, and 3rd zones. The 1st zone showing a highly negative birefringence was the innermost 10 - 15 μm enamel. This zone consisted of arcade and circular initial prisms, and the succeeding arcade prisms only. These initial prisms arising perpendicularly to the dentine surface resembled pseudoprisms because these prisms showed a somewhat centripetal arrangement of crystal lites and indistinct prism boundaries. The succeeding prisms were frequently bent following a faint slit within the prism. The 2nd zone adjacent to the 1st zone measured 20 - 40 μm in thickness. This zone was mainly composed of horseshoe-shaped prisms with EDTA-insoluble prism sheaths in the deep-etched prism boundaries, but the inner-half layer had dotted irregular prisms including circular, double marginal, and spiral shapes with the prism sheaths. Prismless structures were rarely seen in the 2nd zone. The 3rd zone was mainly occupied by horseshoe-shaped prisms without EDTA-insoluble prism sheaths in the deep-etched prism boundaries, although tuft prisms in the 3rd zone contained a large amount of EDTA-insoluble substances in the prisms, interprismatic regions, and the boundaries

Bacillus-Shaped Deposits Composed of Hexahedrally Based Crystals in Human Dental Calculus

In human supra- and subgingival calculus, bacillus-shaped deposits showing various rocky-pile forms composed of hexahedrally based crystals were observed by scanning electron microscopy. The crystal size measured approximately 0.1 - 1.5 μm. The electron probe microanalysis always detected calcium, phosphorous, and magnesium. Their molar ratios resembled those of magnesium-containing whitlockite and moreover the crystals also gave the electron diffraction pattern of whitlockite. The bacillus-shaped deposits happened to coexist with the intracellular calcifying microorganisms, furthermore, oral microorganisms partially replaced by the hexahedrally based crystals were found. The crystal deposits were never seen in the surface layers of calculus exposed to the oral cavity, but occurred in the innermost layers and intra-spaces of supragingival and ledge-type subgingival calculus and in the outer layers of deep subgingival calculus

Attitudes toward depression among Japanese non-psychiatric medical doctors: A cross-sectional study

Abstract Background: Under-recognition of depression is common in many countries. Education of medical staff, focusing on their attitudes towards depression, may be necessary to change their behavior and enhance recognition of depression. Several studies have previously reported on attitudes toward depression among general physicians. However, little is known about attitudes of non-psychiatric doctors in Japan. In the present study, we surveyed nonpsychiatric doctors’ attitude toward depression. Methods: The inclusion criteria of participants in the present study were as follows: 1) Japanese non-psychiatric doctors and 2) attendees in educational opportunities regarding depression care. We conveniently approached two populations: 1) a workshop to depression care for non-psychiatric doctors and 2) a general physician-psychiatrist (GP)network group. We contacted 367 subjects. Attitudes toward depression were measured using the Depression Attitude Questionnaire (DAQ), a 20-item self-report questionnaire developed for general physicians. We report scores of each DAQ item and factors derived from exploratory factor analysis. Results: We received responses from 230 subjects, and we used DAQ data from 187 non-psychiatric doctors who met the inclusion criteria. All non-psychiatric doctors (n = 187) disagreed with "I feel comfortable in dealing with depressed patients' needs," while 60 % (n = 112) agreed with "Working with depressed patients is heavy going." Factor analysis indicated these items comprised a factor termed "Depression should be treated by psychiatrists" - to which 54 % of doctors (n = 101) agreed. Meanwhile, 67 % of doctors (n = 126) thought that nurses could be useful in depressed patient support. The three factors derived from the Japanese DAQ differed from models previously derived from British GP samples. The attitude of Japanese non-psychiatric doctors concerning whether depression should be treated by psychiatrists was markedly different to that of British GPs. Conclusions: Japanese non-psychiatric doctors believe that depression care is beyond the scope of their duties. It is suggested that educational programs or guidelines for depression care developed in other countries such as the UK are not directly adaptable for Japanese non-psychiatric doctors. Developing a focused educational program that motivates non-psychiatric doctors to play a role in depression care is necessary to enhance recognition and treatment of depression in Japan

Honesty mediates the relationship between serotonin and reaction to unfairness

How does one deal with unfair behaviors? This subject has long been investigated by various disciplines including philosophy, psychology, economics, and biology. However, our reactions to unfairness differ from one individual to another. Experimental economics studies using the ultimatum game (UG), in which players must decide whether to accept or reject fair or unfair offers, have also shown that there are substantial individual differences in reaction to unfairness. However, little is known about psychological as well as neurobiological mechanisms of this observation. We combined a molecular imaging technique, an economics game, and a personality inventory to elucidate the neurobiological mechanism of heterogeneous reactions to unfairness. Contrary to the common belief that aggressive personalities (impulsivity or hostility) are related to the high rejection rate of unfair offers in UG, we found that individuals with apparently peaceful personalities (straightforwardness and trust) rejected more often and were engaged in personally costly forms of retaliation. Furthermore, individuals with a low level of serotonin transporters in the dorsal raphe nucleus (DRN) are honest and trustful, and thus cannot tolerate unfairness, being candid in expressing their frustrations. In other words, higher central serotonin transmission might allow us to behave adroitly and opportunistically, being good at playing games while pursuing self-interest. We provide unique neurobiological evidence to account for individual differences of reaction to unfairness

Status of GRB Observations with the Suzaku Wideband All-sky Monitor

The Wide-band All-sky Monitor (WAM) is a function of the large lateral BGO shield of the Hard X-ray Detector (HXD) onboard Suzaku. Its large geometrical area of 800 cm^2 per side, the large stopping power for the hard X-rays and the wide-field of view make the WAM an ideal detector for gamma-ray bursts (GRBs) observations in the energy range of 50-5000 keV. In fact, the WAM has observed 288 GRBs confirmed by other satellites, till the end of May 2007.Comment: 4 pages, 4 figures, to be published in the proceedings of ''Gamma Ray Bursts 2007'', Santa Fe, New Mexico, November 5-

Suzaku X-Ray Imaging and Spectroscopy of Cassiopeia A

Suzaku X-ray observations of a young supernova remnant, Cassiopeia A, were carried out. K-shell transition lines from highly ionized ions of various elements were detected, including Chromium (Cr-Kalpha at 5.61 keV). The X-ray continuum spectra were modeled in the 3.4--40 keV band, summed over the entire remnant, and were fitted with a simplest combination of the thermal bremsstrahlung and the non-thermal cut-off power-law models. The spectral fits with this assumption indicate that the continuum emission is likely to be dominated by the non-thermal emission with a cut-off energy at > 1 keV. The thermal-to-nonthermal fraction of the continuum flux in the 4-10 keV band is best estimated as ~0.1. Non-thermal-dominated continuum images in the 4--14 keV band were made. The peak of the non-thermal X-rays appears at the western part. The peak position of the TeV gamma-rays measured with HEGRA and MAGIC is also shifted at the western part with the 1-sigma confidence. Since the location of the X-ray continuum emission was known to be presumably identified with the reverse shock region, the possible keV-TeV correlations give a hint that the accelerated multi-TeV hadrons in Cassiopeia A are dominated by heavy elements in the reverse shock region.Comment: Publ. Astron. Soc. Japan 61, pp.1217-1228 (2009

Swift captures the spectrally evolving prompt emission of GRB 070616

The origins of Gamma-ray Burst prompt emission are currently not well understood and in this context long, well-observed events are particularly important to study. We present the case of GRB 070616, analysing the exceptionally long-duration multipeaked prompt emission, and later afterglow, captured by all the instruments on-board Swift and by Suzaku WAM. The high energy light curve remained generally flat for several hundred seconds before going into a steep decline. Spectral evolution from hard to soft is clearly taking place throughout the prompt emission, beginning at 285 s after the trigger and extending to 1200 s. We track the movement of the spectral peak energy, whilst observing a softening of the low energy spectral slope. The steep decline in flux may be caused by a combination of this strong spectral evolution and the curvature effect. We investigate origins for the spectral evolution, ruling out a superposition of two power laws and considering instead an additional component dominant during the late prompt emission. We also discuss origins for the early optical emission and the physics of the afterglow. The case of GRB 070616 clearly demonstrates that both broadband coverage and good time resolution are crucial to pin down the origins of the complex prompt emission in GRBs.Comment: 13 pages, 11 figures (2 in colour), MNRAS accepte