CENP-B box is required for de novo centromere chromatin assembly on human alphoid DNA

Centromere protein (CENP) B boxes, recognition sequences of CENP-B, appear at regular intervals in human centromeric α-satellite DNA (alphoid DNA). In this study, to determine whether information carried by the primary sequence of alphoid DNA is involved in assembly of functional human centromeres, we created four kinds of synthetic repetitive sequences: modified alphoid DNA with point mutations in all CENP-B boxes, resulting in loss of all CENP-B binding activity; unmodified alphoid DNA containing functional CENP-B boxes; and nonalphoid repetitive DNA sequences with or without functional CENP-B boxes. These four synthetic repetitive DNAs were introduced into cultured human cells (HT1080), and de novo centromere assembly was assessed using the mammalian artificial chromosome (MAC) formation assay. We found that both the CENP-B box and the alphoid DNA sequence are required for de novo MAC formation and assembly of functional centromere components such as CENP-A, CENP-C, and CENP-E. Using the chromatin immunoprecipitation assay, we found that direct assembly of CENP-A and CENP-B in cells with synthetic alphoid DNA required functional CENP-B boxes. To the best of our knowledge, this is the first reported evidence of a functional molecular link between a centromere-specific DNA sequence and centromeric chromatin assembly in humans

Formation of microbial mats and salt in radioactive paddy soils in Fukushima, Japan

Coastal areas in Minami-soma City, Fukushima, Japan, were seriously damaged by radioactive contamination from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident that caused multiple pollution by tsunami and radionuclide exposure, after the Great East Japan Earthquake, on 11 March 2011. Some areas will remain no-go zones because radiation levels remain high. In Minami-soma, only 26 percent of decontamination work had been finished by the end of July in 2015. Here, we report the characterization of microbial mats and salt found on flooded paddy fields at Karasuzaki, Minami-soma City, Fukushima Prefecture, Japan which have been heavily contaminated by radionuclides, especially by Cs (134Cs, 137Cs), 40K, Sr (89Sr, 90Sr), and91 or 95Zr even though it is more than 30 km north of the FDNPP. We document the mineralogy, the chemistry, and the micro-morphology, using a combination of micro techniques. The microbial mats were found to consist of diatoms with mineralized halite and gypsum by using X-ray diffraction (XRD). Particular elements concentrated in microbial mats were detected using scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS) and X-ray fluorescence (XRF). The objective of this contribution is to illustrate the ability of various diatoms associated with minerals and microorganisms which are capable of absorbing both radionuclides and stable isotopes from polluted paddy soils in extreme conditions. Ge semiconductor analysis of the microbial mats detected 134Cs, 137Cs, and 40K without 131I in 2012 and in 2013. Quantitative analysis associated with the elemental content maps by SEM-EDS indicated the possibility of absorption of radionuclide and stable isotope elements from polluted paddy soils in Fukushima Prefecture. In addition, radionuclides were detected in solar salts made of contaminated sea water collected from the Karasuzaki ocean bath, Minami-soma, Fukushima in 2015, showing high Zr content associated with 137Cs and 40K without 131I. The results obtained here provide evidence of the ability of microorganisms to grow in this salty contaminated environment and to immobilize radionuclides. It is possible that the capability of radioactive immobilization can be used to counteract the disastrous effects of radionuclide-polluted paddy soils. © 2015 by the authors; licensee MDPI, Basel, Switzerland

Equivalency of the quality of sublethal lesions after photons and high-linear energy transfer ion beams

The quality of the sublethal damage (SLD) after irradiation with high–linear energy transfer (LET) ion beams was investigated with low-LET photons. Chinese hamster V79 cells and human squamous carcinoma SAS cells were first exposed to a priming dose of different ion beams at different LETs at the Heavy Ion Medical Accelerator in the Chiba facility. The cells were kept at room temperature and then exposed to a secondary test dose of X-rays. Based on the repair kinetics study, the surviving fraction of cells quickly increased with the repair time, and reached a plateau in 2–3 h, even when cells had received priming monoenergetic high-LET beams or spread-out Bragg peak beams as well as X-ray irradiation. The shapes of the cell survival curves from the secondary test X-rays, after repair of the damage caused by the high-LET irradiation, were similar to those obtained from cells exposed to primary X-rays only. Complete SLD repairs were observed, even when the LET of the primary ion beams was very high. These results suggest that the SLD caused by high-LET irradiation was repaired well, and likewise, the damage caused by the X-rays. In cells where the ion beam had made a direct hit in the core region in an ion track, lethal damage to the domain was produced, resulting in cell death. On the other hand, in domains that had received a glancing hit in the low-LET penumbra region, the SLD produced was completely repaired

Recurrent TMJ open lock

Patient: This report describes the case of a 51-year-old male patient who initially presented at age 23 with a habitual intermittent open lock (at > 35 mm) in the left temporomandibular joint (TMJ). The patient was able to manage this affliction through rapid-repetition jaw opening and closing. Tomography of the joint showed no irregular morphology, but intraoral examination revealed an occlusal interference at the mandibular left third molar during leftwards excursion. For this patient, alteration of lateral guidance using a palatal plate attached to the maxillary left canine precluded this intermittent open lock, but at 22 years of age, the open lock recurred and could not be relieved by the patient, who was unable to assume an occlusal position. Because conservative treatment was ineffective, a pumping manipulation technique was applied to reduce the open lock, after which the patient has maintained good jaw function. MRI taken before and after repositioning indicated that abrupt reduction of a displaced articular disk was the cause of the open lock, and that this articular disk was restored to its proper position during the manipulation. Discussion: Most TMJ open locks occur as anterior dislocation, where the mandibular head becomes trapped anterior to the articular eminences, causing excessive opening and difficulty closing. Our clinical findings from this patient indicate that open lock can occur through abrupt reduction of a displaced articular disk, particularly in patients with chronic internal derangement of the TMJ. Conclusion: TMJ open lock can occur following abrupt reduction of a displaced articular disk

Discriminating the Progenitor Type of Supernova Remnants with Iron K-Shell Emission

Supernova remnants (SNRs) retain crucial information about both their parent explosion and circumstellar material left behind by their progenitor. However, the complexity of the interaction between supernova ejecta and ambient medium often blurs this information, and it is not uncommon for the basic progenitor type (Ia or core-collapse) of well-studied remnants to remain uncertain. Here we present a powerful new observational diagnostic to discriminate between progenitor types and constrain the ambient medium density of SNRs solely using Fe K-shell X-ray emission. We analyze all extant Suzaku observations of SNRs and detect Fe K alpha emission from 23 young or middle-aged remnants, including five first detections (IC 443, G292.0+1.8, G337.2-0.7, N49, and N63A). The Fe K alpha centroids clearly separate progenitor types, with the Fe-rich ejecta in Type Ia remnants being significantly less ionized than in core-collapse SNRs. Within each progenitor group, the Fe K alpha luminosity and centroid are well correlated, with more luminous objects having more highly ionized Fe. Our results indicate that there is a strong connection between explosion type and ambient medium density, and suggest that Type Ia supernova progenitors do not substantially modify their surroundings at radii of up to several parsecs. We also detect a K-shell radiative recombination continuum of Fe in W49B and IC 443, implying a strong circumstellar interaction in the early evolutionary phases of these core-collapse remnants.Comment: Accepted by ApJL; 5 pages with just 1 table and 1 figur

Magnetar Broadband X-ray Spectra Correlated with Magnetic Fields: Suzaku Archive of SGRs and AXPs Combined with NuSTAR, Swift, and RXTE

The 1–70 keV persistent spectra of 15 magnetars, observed with Suzaku from 2006 to 2013, were studied as a complete sample. Combined with early NuSTAR observations of four hard X-ray emitters, nine objects showed a hard power-law emission dominating at ≳ 10 keV with the 15–60 keV flux of ~1–11 x 10^(-11) erg s^(−1) cm^(−2). The hard X-ray luminosity L_h, relative to that of a soft-thermal surface radiation L_s, tends to become higher toward younger and strongly magnetized objects. Their hardness ratio, updated from a previous study and defined as ξ = L_h/L_s, is correlated with the measured spin-down rate P as ξ = 0.62 x (P/10^(-11)s s^(-1))^(0.72), corresponding to positive and negative correlations with the dipole field strength B_d (ξ ∝ B^(1.41)_d) and the characteristic age τ_c (ξ ∝ τ_c^(-0.68)), respectively. Among our sample, five transients were observed during X-ray outbursts, and the results are compared with their long-term 1–10 keV flux decays monitored with Swift/XRT and RXTE/PCA. Fading curves of three bright outbursts are approximated by an empirical formula used in the seismology, showing a ~10–40 day plateau phase. Transients show the maximum luminosities of L_s ~ 10^(35) erg s^(−1), which are comparable to those of persistently bright ones, and fade back to ≾10^(32) erg s^(−1). Spectral properties are discussed in the framework of the magnetar hypothesis

ガク カンセツショウ カンジャ ニオケル MR ガゾウ ショケン ト リンショウ ショケン ノ ヒカク ケントウ

Two hundred eighteen (28.4%) of 768 patients with temporomandibular disorders (TMD), who visited the Clinic for Temporomandibular Disorders, Tokushima University Medical and Dental Hospital during the period of January 2006 through December 2007, were examined using magnetic resonance (MR) imaging. The present study assessed clinico-statistically the correlation between MR images and the clinical findings of 157 patients with complete registered data in our TMD reporting system. The following findings were obtained: 1. MR imaging showed anterior disk displacement in 125 joints (67.9%), rotational disk displacement in 45 joints (24.5%), and sideways disk displacement in 13 joints (7.1%). 2. Joint effusion (JE) was found in 42.7% of 157 patients; 48.0% in females and 23.5% in males. In addition, anterior or rotational disk displacement was observed in 97% of patients with JE. Furthermore, condyle bone change was significantly higher in joints with than without JE. 3. The appearance of JE was significantly higher on the symptomatic side than the asymptomatic side, but tenderness of the temporomandibular joint (TMJ) area or the value of the visual analog scale (VAS) regarding pain and problems in daily life was not related to the presence of JE

An Optimized Photoelectron Track Reconstruction Method for Photoelectric X-Ray Polarimeters

We present a data processing algorithm for angular reconstruction and event selection applied to 2-D photoelectron track images from X-ray polarimeters. The method reconstructs the initial emission angle of a photoelectron from the initial portion of the track, which is obtained by continuously cutting a track until the image moments or number of pixels fall below tunable thresholds. In addition, event selection which rejects round tracks quantified with eccentricity and circularity is performed so that polarimetry sensitivity considering a trade-off between the modulation factor and signal acceptance is maximized. The modulation factors with applying track selection are 26.6 0.4, 46.1 0.4, 62.3 0.4, and 61.8 0.3% at 2.7, 4.5, 6.4, and 8.0 keV, respectively, using the same data previously analyzed by Iwakiri et al. (2016), where the corresponding numbers are 26.90.4, 43.40.4, 54.40.3, and 59.1 0.3%. The method improves polarimeter sensitivity by 5%10% at the high energy end of the band previously presented (Iwakiri et al. 2016)