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Maxillary canines require the longest period from the generation of the tooth germ to the completion of eruption, and they have more difficulties in eruption than other teeth. The incisor roots are often resorbed due to malpositioned canines. An 11-year-old girl presented with an extremely rare case of root resorption of four maxillary incisors due to bilaterally impacted maxillary canines, which were located excessively mesially. The case was managed through oral surgery and orthodontic treatment over five years. After extracting the maxillary deciduous canines, the maxillary bilateral canines were surgically exposed. The bimaxillary lateral incisors were extracted, and the canines were orthodontically tracted over 8 months. All teeth were then aligned using edgewise brackets. No further root resorption of the central incisors was observed for 5 years after canine traction. This case demonstrates the importance of early detection of abnormally positioned canines.

Ag+ ions were intercalated into the transition-metal dichalcogenide TaS2 using the recently developed method of proton-driven ion introduction. Single-crystalline Ag0.58TaS2 with a stage 1 structure and Ag0.21TaS2 with a stage 2 structure were prepared using this method. The stage 2 structure of Ag0.21TaS2 was formed by exploiting the differences in ion diffusion properties among the polytypes of TaS2. Furthermore, our intercalation method can forcibly insert Ag+ ions into interlayers by applying a high voltage at low temperature (100 degrees C), resulting in the formation of thermodynamically metastable phase. Such a synthesis approach oilers a potential route for diversifying intercalation compounds with different stage structures. The first observations of superconductivity in AgxTaS2 were demonstrated in this study. The onset of superconductivity of AgxTaS2 was estimated to be 0.4 and 1.7 K in the samples with x = 0.58 and x = 0.21, respectively. Some anomalies, which were speculatively attributed to charge density wave order, were confirmed in the resistivity measurements of AgxTaS2. The results suggested that the anomalies were closely correlated with the superconducting transition temperature. (C) 2018 The Ceramic Society of Japan. All rights reserved.

The CCCTC-binding factor (CTCF) works together with the cohesin complex to drive the formation of chromatin loops and topologically associating domains, but its role in gene regulation has not been fully defined. Here, we investigated the effects of acute CTCF loss on chromatin architecture and transcriptional programs in mouse embryonic stem cells undergoing differentiation to neural precursor cells. We identified CTCF-dependent enhancer-promoter contacts genome-wide and found that they disproportionately affect genes that are bound by CTCF at the promoter and are dependent on long-distance enhancers. Disruption of promoter-proximal CTCF binding reduced both long-range enhancer-promoter contacts and transcription, which were restored by artificial tethering of CTCF to the promoter. Promoter-proximal CTCF binding is correlated with the transcription of over 2,000 genes across a diverse set of adult tissues. Taken together, the results of our study show that CTCF binding to promoters may promote long-distance enhancer-dependent transcription at specific genes in diverse cell types.

Summary of PBAT-seq with human and mouse genomic DNA using different HCS and RTA versions. Table S2. Summary of PBAT-seq with in vitro methylated lambda phage DNA. Table S3. Summary of the effect of cluster density on PBAT-seq using different HCS versions. Table S4. Bisulfite PCR primers for lambda DNA. Figure S1. Experimental design to investigate the effect of HCS and RTA updates. Figure S2. Different CpG methylation levels obtained for identical PBAT libraries using different HCS and RTA versions. Figure S3. Changes in global CpG methylation level during mouse cell differentiation. Figure S4. Bisulfite sequencing of in vitro CpG methylated lambda DNA at three selected loci. Figure S5. Quality scores assigned to the four bases. Figure S6. WGBS data generated by new Illumina systems. (PDF 1211 kb)

Figure S1: Expression of key molecular markers in isolated cells. Figure S2: CG methylation at ICRs and retrotransposons. Figure S3: PMD distribution in each chromosome. Figure S4: Replication-dependent loss of 5mC and 5hmC in neonatal spermatogonia after the resumption of mitosis. Figure S5: Changes in gene expression levels between stages. Figure S6: Genes involved in the signal transduction pathways for SSC self-renewal have stage-specific DMRs. Figure S7: Expression dynamics of transcription factors listed by motif analysis of the DMRs. Figure S8: Motifs found in the representative DMRs. (PDF 26886 kb)

Objectives: Small animal imaging has recently been focused on basic nuclear medicine. We have designed and built a small animal SPECT imaging system using a semiconductor camera and a newly designed collimator. We assess the performance of this system for small object imaging. Methods: We employed an MGC1500 (Acrorad Co.) camera including a CdTe semiconductor. The pixel size was 1.4 mm/pixel. We designed and produced a parallel-hole collimator with 20-mm hole length. Our SPECT system consisted of a semiconductor camera with the subject holder set on an electric rotating stage controlled by a computer. We compared this system with a conventional small animal SPECT system comprising a SPECT-2000H scanner with four Anger type cameras and pinhole collimators. The count rate linearity for estimation of the scatter was evaluated for a piechart phantom containing different concentrations of 99mTc. We measured the FWHM of the 99mTc SPECT line source along with scatter. The system volume sensitivity was examined using a flood source phantom which was 35 mm long with a 32-mm inside diameter. Additionally, an in vivo myocardial perfusion SPECT study was performed with a rat. Results: With regards to energy resolution, the semiconductor camera (5.6%) was superior to the conventional Anger type camera (9.8%). In the count rate linearity evaluation, the regression lines of the SPECT values were y = 0.019x + 0.031 (r2 = 0.999) for our system and y = 0.018x + 0.060 (r2 = 0.997) for the conventional system. Thus, the scatter count using the semiconductor camera was less than that using the conventional camera. FWHMs of our system and the conventional system were 2.9 ± 0.1 and 2.0 ± 0.1 mm, respectively. Moreover, the system volume sensitivity of our system [0.51 kcps/(MBq/ ml)/cm] was superior to that of the conventional system [0.44 kcps/(MBq/ml)/cm]. Our system provided clear images of the rat myocardium, sufficient for practical use in small animal imaging. Conclusions: Our SPECT system, utilizing a semiconductor camera, permits high quantitative analysis by virtue of its low scatter radiation and high sensitivity. Therefore, this system may contribute to molecular imaging of small animals and basic medical research.

小型被写体用超高エネルギー用コリメータの設計と作製を行った．作製したピンホールコリメータは，径0.6 mmで許容角度は13°であった．このピンホールから被写体までの距離と幾何学的感度，および距離と視野サイズの関係を計算した．次にガンマカメラに装着して18Fにおける総合空間分解能と総合感度を測定した．また超高エネルギー用コンバージングコリメータも設計した．ピンホールコリメータの計算結果は，距離を近づけると幾何学的感度は高くなったが，視野は狭まった． 測定した結果においてFWHMは2.4 mm，FWTMは9.5 mm，総合感度は6.8 counts sec –1 MBq–1であった．一方，コンバージングコリメータは視野の大きさの制限，視野周辺部の感度低下を受けないことが示唆された．このようにピンホールコリメータで超高エネルギーの高空間分解能撮像に成功した．またコンバージングコリメータの方は，臨床機への応用も可能と考えられた．, Recently, small object imaging using positron emitters, such as fluorine-18-2-deoxyglucose, has focused on basic nuclear medicine techniques. We have designed and developed ultra-high-energy high-resolution collimators for small object imaging. Firstly, we produced an ultra-high-energy pinhole collimator. The thickness of the lead shielding was 30 mm. The pinhole diameter of knife-edge aperture was 0.6 mm. The acceptance angle was 13°. This cylinder was equipped with a non-collimator gamma camera at a distance of 30.5 cm. The radius of rotation was 6 cm and the magnification was 5.1 times. In simulation calculations, as the pinhole-object distance decreased, geometric sensitivity increased geometrically. However, as the pinhole-object-distance decreased, field-of-view (FOV) decreased linearly. Spatial resolution was measured using a line source of 18F and was 2.4 mm at full-width-at-half-maximum and 9.5 mm at full-width-at-tenth-maximum. The sensitivity of the system was 6.8 counts sec–1 MBq–1 using a point source of 18F. In addition, sensitivity at the rim of FOV was lower than that at the center. Next, we designed an ultra-high-energy converging collimator. It was found that the converging collimator had uniform sensitivity over the FOV. Also, the FOV at smaller collimator-object distances was not as restricted as the ultra-high-energy pinhole collimator. Thus, we demonstrated that high-resolution images for ultra-high-energy imaging could be acquired using the pinhole collimator. Moreover, we believe that the ultra-high-energy converging collimator could be available for a clinical study.

A practical training program that enabled students to experience an aged person and hemiplegia patient was developed as part of the "Practice Program in Medical Imaging Technology," to help the students understand how to support patients in the X-ray examination setting. Eighty-three third-year radiological technology students participated in the program. During the hour-long course, they experienced a simulated program that contained various checkpoints. The students pointed out the difficulty patients had in going up and down stairs (51.8%) and their feelings of uneasiness and fear of blindness (36.1%). As a result of this practical training program, the students increased their understanding of how to support patients slated for X-ray examinations. However, certain problems became clear, such as students' insufficient experience and lack of practical guidance in supporting aged patients and those with hemiplegia at the time of X-ray examinations. This information will helpful for improving similar training programs to be held in the future.

短報

「久保直樹，花田博之著：Non-Collimatorによるシンチグラムの画像復元について, 北海道大学医療技術短期大学部紀要，8, p.151-156(1995)」の英訳版, We have conducted an experiment on restoring scintigram images obtained without the use of collimators. Uncollimated images of liver slice phantoms filled with 99mTc were taken at a phantom-camera distance of 0 cm. The sensitivity under these conditions was about one thousand times higher than that using a low-energy high-resolution collimator. Uncollimated images were restored using unsharp masking in combination with spatial filtering. The unsharp masking process involved subtracting two images taken at phantom-camera distances of 0 and 2.3 cm to produce a difference image. The mean squared errors found were 0.56 for the uncollimated images, 0.54 for the images processed with the spatial filter only, and 0.53 for the images produced using unsharp masking followed by spatial filtering. Thus, the images processed using both unsharp masking and the spatial filter bore the closest resemblance to the actual images. Also, since this method was capable of revealing the shape of the phantom, it may already be usable for imaging large lesions, such as in lung perfusion scintigraphy.

「久保直樹著：フィルタ補正逆投影法・逐次近似法について、START, 48, p.13-15(2012)」の英訳版, The following two duties are expected of us: (1) to assist in interpretation of diagnostic images, and (2) to provide detailed explanations of radiological examinations. As professionals, we owe it to our clients to maintain our competence in perceiving the reality of each person’s condition during radiological examinations; we must neither nderestimate their radiation exposure risks nor overestimate the benefits they may receive from the examination. When assisting in interpretation of diagnostic images, we must understand the characteristics of images that can affect our assessment. Moreover, turning to the topic of reconstructed images, much information can be gathered from images utilizing the full capability of econstruction algorithms. Image quality is highly dependent upon the method of reconstruction (calculation of tomographic images). Reconstruction can be broadly classified into the following two types: filtered back projection and iterative reconstruction.

PETにおける三次元関心領域抽出ソフトウェア,心電図同期心筋SPECT用解析アルゴリズムの違いによる心基部弁膜面の再現性,心電図同期心筋PET用心筋厚自動測定ソフトウェア,の開発と検討を行った.その結果,PETからの三次元関心領域抽出を実現でき,心基部弁膜面設定における閾値法の再現性の高さを立証することができた.また,心電図同期PETから心筋厚を算出するソフトウェアを開発することができた.これにより代謝のみではなく,心筋厚から左心室機能や心疾患の判定情報を与えることが可能となると考えられた．

低線量撮影したX線CT画像の画質を改善する画像処理フィルタ設計法を開発した。また同じ目的を達成するために別の手法として，スムージングを施してもエッジを保存する新しい関数系を開発した。空間フィルタの特性はウィナーフィルタに類似した形とした。低線量撮影したCT画像を，本手法のフィルタを施すことでコントラストを保ちつつ，雑音を抑制できることができた。新しい関数系は，符号がオリジナルの三角関数と等しく，振幅が三角関数の平方根となっている。今回開発した関数系は，フーリエ変換よりエッジを保存してスムージングできることが確認できた。これにより低線量撮影した画像の雑音を抑えるためスムージングをしても質の高い画像を提供することができる。