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Intracranial solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is a relatively rare type of tumor that originates from meningeal mesenchyme. A 30-year-old man presented leaning his body to the left and with weakness of his left lower limb. Computed tomography revealed a heterogeneous mass with multiple cystic components and hyperostosis of the right cranial convexity. Magnetic resonance imaging showed the mass was broadly attached to the dura matter with dural tail sign. In addition, the lesion had extensive cystic degeneration and a solid compartment showing low apparent diffusion coefficient values. The patient underwent gross total resection of the intracranial lesion and presented no recurrence within a 12-month follow-up period. Histopathology confirmed SFT/HPC (World Health Organization grade Ⅱ). Although there have been several useful techniques reported to differentiate SFT/HPC from meningioma, in this case the atypical findings for SFT/HPC made it difficult. We report the imaging findings of this case and some literature reviews.

Some of the detachable microcoils are associated with the prominent metallic artifact. We have applied Silent MRA to reduce the artifact. In this study, we present a retrospective study in which Silent MRA is used for cases showing prominent metallic artifact on conventional TOF-MRA due to a detachable bare platinum microcoil (Barricade coil). Fifteen patients, who had undergone endosaccular embolization using Barricade coil and other detachable microcoils up to 3 days previously, were scanned with TOF-MRA and silent MRA at the same time. The treatment DSA and follow-up MRA images were graded by two experienced neuroradiologists, focusing on the visibility of residual aneurysm and parent arterial lumen. DSA images showed residual aneurysm (RA) in four, residual neck (RN) in six, and complete occlusion (CO) in five patients. TOF-MRA images showed RN in five, CO in four, mild defect (MD) in one, severe defect (SD) in three, and complete defect in two. In contrast, on Silent MRA, the grades were RA in two, RN in five, CO in five, and MD in three. Barricade coils are associated with prominent metallic artifact on TOF-MRA. Silent MRA is useful for follow-up MRA after embolization using Barricade coils. The metallic artifacts were compared between TOF-MRA and Silent MRA in patients treated by using Barricade coils. Barricade coils are associated with more metallic artifact on TOF-MRA than Silent MRA. Silent MRA is useful for follow-up MRA after embolization using Barricade coils.

Paroxysmal kinesigenic dyskinesia (PKD) is a movement disorder characterized by episodic involuntary movement attacks triggered by sudden movements, acceleration, or intention to move. We ascertained two Japanese familial cases with PKD. The proband is a 22-year-old woman who had noted sudden brief (30 s) of involuntary movements provoked by kinesigenic trigger such as starting to run, getting on a train, picking up a telephone receiver and so on at the age of 14. Interictal brain single photon emission computed tomography (SPECT) showed hyperperfusion in the left thalamus. A 46-year-old woman, the mother of the proband was also suffering from brief attacks triggered by starting to run in her high school days. On neurological examination, both showed no abnormality. Whole exome sequencing combined with rigorous filtering revealed two heterozygous nonsynonymous variants (NM_001447: c.8976GC [p.Gln2992His] in FAT2 and NM_015678: c.8596CT [p.Arg2866Trp] in NBEA). Real time quantitative PCR analysis of Nbea mRNA levels in the developing rat brain revealed peak at postnatal day 28 and decline at postnatal day 56. This result might match the most common clinical course of PKD from the point of view of the most common age at remission. NBEA has been reported to be responsible for neurodevelopmental disease accompanied by epilepsy. We concluded the variant in NBEA most likely to be responsible for our familial cases of PKD.

We describe a 61-year-old woman with bilateral parkinsonism caused by unilateral infarction limited to the territory of the lenticulostriate arteries. Although dopamine transporter imaging with single-photon emission computed tomography (DaTSPECT) demonstrated reduced putaminal tracer binding concordant with the size and location of the vascular lesion, the specific binding ratio was within the normal range. Five months after onset, the patient was free from parkinsonism without the use of any antiparkinsonian agents. When patients show bilateral parkinsonism, it is important to consider infarction of the lenticulostriate arteries. Additionally, DaTSPECT might be useful for predicting the prognosis of parkinsonism caused by infarction., Highlights • We present a case with bilateral parkinsonism caused by unilateral striatum infarcts. • DaTSPECT showed right putamen hypoactivity. • However, specific binding ratio was within the normal range. • Her symptoms fully recovered without antiparkinsonian agents. • DaTSPECT may be useful for us to predict a patient's prognosis.

The natural blind spot in the visual field has been known as a large oval region that cannot receive any optical input because it corresponds to the retinal optic disk containing no rod/cone-photoreceptors. Recently, stimulation inside the blind spot was found to enhance, but not trigger, the pupillary light reflex. However, it is unknown whether blind-spot stimulation also affects visual perception. We addressed this question using psychophysical brightness-matching experiments. We found that a test stimulus outside the blind spot was judged as darker when it was accompanied by a consciously unexperienced blue oval inside the blind spot; moreover, the pupillary light reflex was enhanced. These findings suggested that a photo-sensitive mechanism inside the optic disk, presumably involving the photopigment melanopsin, contributes to our image-forming vision and provides a ‘reference’ for calibrating the perceived brightness of visual objects.

Cerebral air embolism following central venous catheter (CVC) removal is extremely rare. We report a case of cerebral air embolism with loss of consciousness after removal of CVC caused by pulmonary arteriovenous malformation (PAVM). Computed tomography revealed air bubbles in the internal carotid arteries along the sulci in the cerebral hemispheres, as well as a PAVM. The cerebral air embolism was treated with hyperbaric oxygen and intravenous thrombolytic therapy, and transcatheter embolization of the PAVM was performed. When inserting/removing CVC in a patient with a small PAVM, treatment of the PAVM, irrespective of its size, could prevent the type of complication that occurred in our present case.

Imaging findings of pilocytic astrocytoma (PA) vary widely, sometimes resembling those of high-grade glioma (HGG). This study aimed to identify the imaging parameters that can be used to differentiate PA from HGG. Altogether, 60 patients with PAs and 138 patients with HGGs were included in the study. Tumor properties and the presence of hydrocephalus, peritumoral edema, and dissemination were evaluated. We also measured the maximum relative cerebral blood flow (rCBFmax) and volume (rCBVmax) and determined the minimum apparent diffusion coefficient (ADCmin) in the tumor’s solid components. The relative T1 (rT1), T2 (rT2), and contrast-enhanced T1 (rCE-T1) intensity values were evaluated. Parameters were compared between PAs and HGGs using the Mann–Whitney U test. Receiver operating characteristic (ROC) curve analysis was also used to evaluate these imaging parameters. A value of P

There are no specific radiologic features in MOG-Ab (autoantibodies directed against myelin oligodendrocyte glycoprotein)-associated diseases. We present two MOG-Ab-positive patients with symmetrical lesions in the bilateral cingulate cortex of the frontal and parietal lobes. Those lesions showed hyperperfusion in acute phase and hypoperfusion in chronic phase on brain SPECT. In both patients, steroid therapy was effective in acute phase and for prevention of recurrence. High signal in the bilateral cingulate cortex on MR T2-weighted and FLAIR images might to be one of the unique findings considered MOG-Ab associated diseases.

Recent findings have indicated a close relationship between myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA)-positive hypertrophic pachymeningitis and the limited form of granulomatosis with polyangiitis (GPA). In Japan, MPO-ANCA-positive hypertrophic pachymeningitis predominantly occurs in elderly individuals. We herein describe the cases of two patients with MPO-ANCA-positive hypertrophic pachymeningitis associated with the limited form of GPA who were successfully treated with a combination of corticosteroids and methotrexate. Although methotrexate has been shown to be less effective than cyclophosphamide for inducing the remission of GPA in patients with organ-threatening diseases, its safety and efficacy may make it a useful alternative treatment modality for patients with the limited form of GPA who show meningeal involvement.

We describe a 60-year-old woman with combined central and peripheral demyelination who presented with obstinate constipation, weakness in the lower limbs, and a bilateral sensory disturbance below her chest followed by girdle sensation in the right region of the abdomen, which was responsive to steroid therapy and plasmapheresis. Serum anti-lactosylceramide antibody was positive without anti-neurofascin 155 antibody or anti-galactocerebroside antibody positivity. Two months later, the patient had a first relapse that was responsive to steroid treatment. A nerve conduction study confirmed reversible conduction failure (RCF) in both episodes. Our case is unique in that she had an RCF episode as well as some similarities to encephalomyeloradiculoneuropathy.

An Eulerian passive tracer model coupled with a quadruple-nested 3D circulation model was used to assess the coastal dispersal of treated wastewater effluent from a sewage treatment plant and the associated impacts on an adjacent seaweed farm using three different operational scenarios. When the discharged volume and source effluent fluxes were decreased by ~16.7%, the accumulated effluent in the farm was reduced by ~25.4%. A tracer flux budget analysis revealed the apparent predominance of the transient component that accounts for the nonlinear interactions primarily from tidal currents and eddies. The transient flux promoted the effluent influx to impede effluent accumulation in the farm, whereas the mean flux contributed to the outgoing flux. A source flux reduction caused a remarkable decrease in the transient flux and thus an even greater effluent accumulation reduction. In turn, a modified source density scenario without total effluent volume change did not work as expected.

A positron timing counter (TC) with 30–40 ps time resolution for 50 MeV/c positrons required by the MEG II experiment has been developed. We employed a highly segmented design with 512 scintillator plates (120 × 40 × 5 mm3 and 120 × 50 × 5 mm3) read out by 6-SiPM-arrays at the both ends. Pile up is reduced by the segmented design and multi-counter measurement improves the overall timing resolution. All the single counters were assembled and their resolutions were measured to be below 100 ps in a pre-test with a 90 Sr source. The construction and installation were completed in 2017. An engineering run was performed at the end of 2017 at the π E5 muon beam line in PSI, which supplies the most intense muon beam (7 × 107 stops/s on a target) in the world. We successfully operated the full system of TC in the MEG II environment and achieved a time resolution below 40 ps with more than 6 counter hits. The overall resolution for the signal positrons is estimated to be 38.5 ps by weighting the obtained resolutions with the number of hits distribution of the signal positrons obtained by a Monte Carlo simulation. The time resolution of the TC is improved by a factor of 2 with respect to the MEG experiment.

We have developed a new laser-based time calibration system for highly segmented scintillator counters like the MEG II pixelated Timing Counter (pTC), consisting of 512-centimeter scale scintillator counters read out by silicon photomultipliers (SiPMs). It is difficult to apply previous laser-based calibration methods for conventional meter-scale Time-Of-Flight detectors to the MEG II pTC from the implementation and the accuracy points of view. This paper presents a new laser-based time calibration system which can overcome such difficulties. A laser pulse is split into each scintillator counter via several optical components so that we can directly measure the time offset of each counter relative to the laser-emitted time. We carefully tested all the components and procedures prior to the actual operation. The laser system was installed into the pTC and thoroughly tested under the real experimental condition. The system showed good stability and being sensitive to any change of timing larger than ~10 ps. Moreover, it showed an uncertainty of 48 ps in the determination of the time offsets, which meets our requirements. The new method provides an example of the implementation of a precise timing alignment for the new type of detectors enabled by the advance of SiPM technology., Comment: 11 pages, 17 figures

The MEG II experiment (Baldini et al., 2018) [1] is designed to improve the sensitivity to the μ + → e + γ decay. A crucial component is the Pixelated Timing Counter (pTC), dedicated to the measurement of the positron time to reduce the combinatorial background (Cattaneo et al., 2014; Nishimura et al., 2016) [3,4]. The detector consists of 512 scintillation counters , each performing a precise measurement of the positron crossing time. This approach requires that the time offsets of the counters are calibrated and regularly monitored over the lifetime of the experiment. The pTC time calibration and monitor system will use a laser diode to deliver pulses to each pixel. The system components have been tested in laboratory, the results demonstrate that a calibration and monitoring resolution satisfying the requirements is within reach.

This paper discusses the effects of radiation damage to SiPMs on the performances of plastic scintillator counters with series-connected SiPM readout, focusing on timing measurements. The performances of a counter composed of a $120 \times 40 \times5~\mathrm{mm}^3$ scintillator tile read out by two sets of six SiPMs from AdvanSiD connected in series attached on the short sides are presented, for different combinations of SiPMs at various levels of irradiation. Firstly, six SiPMs were equally irradiated with electrons from $^{90}$Sr sources up to a fluence of $\Phi_\mathrm{e^-}\approx 3 \times 10^{12}~\mathrm{cm}^{-2}$. The timing resolution of the counter gradually deteriorated by the increase in dark current. The dark current and the deterioration were reduced when the counter was cooled from 30$^\circ$C to 10$^\circ$C. Secondly, 33 SiPMs were irradiated with reactor neutrons. The characteristics of counters read out by series-connected SiPMs with non-uniform damage levels, were investigated. The signal pulse height, the time response, and the timing resolution depend on the hit position in the counter, when SiPMs' irradiation is not uniform., Comment: 13 pages, 27 figures, Major revision based on the reviewers' comments

Financial time series have been investigated to follow fat-tailed distributions with truncations. In order to identify the nature of such fluctuations, we proposed a stochastic volatility model by incorporating the cut-off effect in superstatistics. Then we confirm that the proposed stochastic model is capable of describing the statistical properties of real financial time series. In addition, we present an option pricing formula with respect to superstatistics. A new type of anomalous fluctuations is also investigated based on the proposed stochastic model.

Spinocerebellar ataxia 27 (SCA27) is an autosomal dominant SCA caused by variants in the fibroblast growth factor 14 (FGF14) gene. We examined a Japanese SCA patient whose deceased father also suffered from SCA. The patient was a 63-year-old male. He graduated from junior high school but received no further education. The predominant complaint was slowly progressive dysarthria and gait disturbance, which appeared at age 47. He showed pathological saccadic dysmetria, saccadic intrusions into smooth pursuit eye movements, dysarthria, and limb and truncal ataxia. His gait was wide-based but he did not require a walking stick. Limb muscle strength was intact. Deep tendon reflexes were normal or slightly reduced. Pathological reflexes were absent. He demonstrated mildly impaired vibration sense in the lower limbs. There was no urinary dysfunction. Brain MRI showed cerebellar atrophy without brainstem involvement. We first confirmed the absence of repeat expansion in genes known to be responsible for SCAs 1-3, 6-8, 10, 12, 17, 36 and dentatorubral-pallidoluysian atrophy. By exome analysis, we identified a novel heterozygous variant (NM_004115, c.529A>T; Lys177X) in exon 4 of the FGF14 gene. This variant is expected to generate a truncated FGF14 protein lacking the heparin binding sites, those are likely to modify the activity of FGF14. We confirmed the absence of the variant in 502 healthy Japanese individuals by Sanger sequencing. There is no record of the variant in public databases. We conclude that the novel variation in FGF14 is causative for SCA27 in this patient.

This study aimed to make a timing counter of the best time resolution with an about 10 cm square plastic scintillator read out by multiple SiPMs. To achieve this, SiPM connection scheme, counter geometry and difference of plastic scintillators were investigated. As a result, the best time resolution was achieved with a counter of 80 × 175 × 5 mm 3 EJ-230 read out on each side by four readout channels of four SiPMs connected in series, marking σ t = 28 ps with position dependence less than 5 ps.

We studied the impact of radiation damage on scintillation counters read out by six SiPMs connected in series focusing on their time resolution. Six SiPMs from AdvanSiD were irradiated step by step with a 37 MBq 90Sr source. At the integrated dose expected at the end of the MEG II experiment, the time resolution at 30 °C was measured to be worse by ∼ 29%. However, the deterioration is found to be reduced to ∼ 6% at 10 °C since thermal dark noise is suppressed. We also tested the effect of connecting in series differently damaged SiPMs. We observed a position dependence of the time center in a counter, which worsened the time resolution.

The liquid xenon (LXe) γ-ray detector for the MEG II experiment is based on a highly granular scintillation readout with Multi-Pixel Photon Counters (MPPCs). Here we report on the development of a large-area MPPC sensitive to LXe scintillation light in deep-UV range for the MEG II LXe detector. A prototype model of the deep-UV MPPC with an active area of 12 × 12 mm 2 was successfully tested in LXe, showing an excellent performance such as a high photon detection efficiency for the LXe scintillation light (about 20% at Δ V = 2.5 V ), a high internal gain (about 10 6 at Δ V = 2.5 V ) and an excellent single photoelectron resolution. The sensor chip of the MPPC is segmented into four sectors, which are then connected in series in order to reduce the overall sensor capacitance. The signal fall time of about 135 ns for the non-segmented sensor was significantly reduced down to 25 ns with the series-connected sensor segments. The preliminary results on the performance of the deep-UV MPPC are presented.

Hematoma expansion is an important consideration in patients with traumatic brain injury (TBI). No precise methods are available, however, for predicting the expansion of TBI-related hematoma. We aimed to establish a more sensitive predictor for contusional hematoma expansion based on the presence of leakage signs on computed tomography angiography (CTA). Thirty-three patients with pure contusion were included in the analysis (age: 64.1 ± 20.6 years; 24 men and 7 women). We compared Hounsfield unit (HU) values within set regions of interest (diameter, 10 mm) between serial CTA phase and delayed-phase CT images (5 min after CTA phase). Positive leakage signs were defined as10% increases in HU value. Hematoma expansion was determined using plain CT at 24 h in patients who did not undergo emergent surgery. Glasgow Coma Scale (GCS) scores measured at admission and 24 h after admission were also compared. Leakage signs predicted hematoma expansion with high specificity (100%) and sensitivity (92.8%). Patients with positive leakage signs had significant decreases in GCS scores 24 h after the scan (GCS change: positive group, -0.92 ± 0.59; negative group, 1.14 ± 0.82). Positive leakage signs were clearly associated with surgical hematoma removal. Five patients without hematoma who had positive leakage signs at admission exhibited significant expansion of hematomas 24 h later. Our results indicate that leakage signs had high sensitivity in the prediction of contusional hematoma expansion and were significantly associated with delayed neurological deterioration and the necessity of surgical removal.

Background: Brain hemorrhage is a serious complication of antiplatelet therapy, particularly dual antiplatelet therapy (DAPT), in patients with coronary artery disease (CAD) who undergo percutaneous coronary intervention (PCI). It has been suggested that cerebral micro bleeds (CMBs) detected on magnetic resonance imaging (MRI) are a risk factor for future cerebral haemorrhage. However, little is known about CMBs in CAD patients during antiplatelet therapy. We investigated the temporal changes of CMBs and determined the risk factors for CMBs in patients with CAD on antiplatelet therapy. Methods: This study prospectively enrolled 14 CAD patients who underwent antiplatelet therapy (DAPT in 13 patients) and had no history of symptomatic stroke. Brain MRI was performed at baseline and after 8-month follow-up. Results: Baseline MRI revealed CMBs in two patients (14%). New CMBs were detected by follow-up MRI in two other patients (14%). CMB-positive patients had a greater number of coronary artery lesions (p=0.04) and a tendency to have a higher SYNTAX score at baseline (p=0.06) than CMB-negative patients. Although blood pressure (BP) at baseline did not differ between the CMB-positive and CMB-negative patients, BP after 8 months was significantly higher in CMB-positive than in CMB-negative patients (systolic BP: p=0.03, diastolic BP: p=0.02). Conclusions: CAD patients with severe coronary artery lesions and poor BP control appear to be at higher risk for CMBs during antiplatelet therapy. Accordingly, strict coronary risk control, especially BP control, is necessary to prevent new CMBs in CAD patients receiving long-term antiplatelet therapy

A new timing detector has been developed to measure ∼50 MeV/c positrons with a time resolution of σ t ≃ 30 ps in the MEG II experiment. The detector are segmented into 512 scintillation counters, each of which consists of 120 × ( 40 or 50 ) × 5 mm 3 size BC-422 and two arrays of six AdvanSiD silicon photomultipliers. The single-counter resolutions are measured to be 70–80 ps. The counter layout is optimized to get the maximum number of hit counters (on average 9 for signal positrons). This multiple-counters measurement leads to a significant improvement in the time resolution down to 30 ps. Using the first one-fourth (128) counters, a pilot run was carried out using the MEG II beam of 7 × 10 7 μ + / s and the basic functionality was tested.

High-time-resolution counters based on plastic scintillator with silicon photomultiplier (SiPM) readout have been developed for applications to high energy physics experiments for which relatively large-sized counters are required. We have studied counter sizes up to $120\times40\times5$ mm^3 with series connection of multiple SiPMs to increase the sensitive area and thus achieve better time resolution. A readout scheme with analog shaping and digital waveform analysis is optimized to achieve the highest time resolution. The timing performance is measured using electrons from a Sr-90 radioactive source, comparing different scintillators, counter dimensions, and types of near-ultraviolet sensitive SiPMs. As a result, a resolution of $\sigma =42 \pm 2$ ps at 1 MeV energy deposition is obtained for counter size $60\times 30 \times 5$ mm^3 with three SiPMs ($3\times3$ mm^2 each) at each end of the scintillator. The time resolution improves with the number of photons detected by the SiPMs. The SiPMs from Hamamatsu Photonics give the best time resolution because of their high photon detection efficiency in the near-ultraviolet region. Further improvement is possible by increasing the number of SiPMs attached to the scintillator., Comment: 11 pages, 17 figures, accepted by IEEE Trans. Nucl. Sci

Background: In some cases of acute brainstem infarction (BI), standard axial diffusion-weighted imaging (DWI) does not show a lesion, leading to false-negative (FN) diagnoses. It is important to recognize acute BI accurately and promptly to initiate therapy as soon as possible. Methods: Of the 171 patients with acute cerebral infarctions in our institution who were examined, 16 were diagnosed with true-positive BI (TP-BI) and six with FN-BI. We evaluated the effectiveness of sagittal DWI in accurately diagnosing acute BI and sought to find the cause of its effectiveness by the anatomical characterization of FN-BIs. Results: Considering the direction of the brainstem perforating arteries, we supposed that sagittal DWI might more effectively detect BIs than axial DWI. We found that sagittal DWI detected all FN-BIs more clearly than axial DWI. The mean time between the onset of symptoms and initial DWI was significantly longer in the TP group (17.6 ± 5.5 h) than in the FN group (5.0 ± 1.2 h; P < 0.0001). The lesion volumes were much smaller in FN-BIs (259 ± 82 mm3) than in TP-BIs (2779 ± 767 mm3; P = 0.0007). FN-BIs had a significant inverse correlation with the ventrodorsal length of infarcts (FN 3.5 ± 1.1 mm, TP 11.4 ± 3.6 mm; P < 0.0004) and no correlation with other size parameters such as rostrocaudal thickness and lateral width. Conclusion: Anatomical characterization clearly confirmed that the addition of sagittal DWI to the initial axial DWI in suspected cases of BI ensures its accurate diagnosis and improves the patient’s prognosis.

Coastal dispersal of sewage effluent from the Tarumi Sewage Treatment Plant located in Osaka Bay, Japan, was investigated with a quadruple-nested high-resolution ROMS model coupled with a 3-D passive tracer model. The study area is quite famous for seaweed farming in the nation, which has been claimed considerably affected by the effluent from the plant, particularly in fall when the seaweed spores are most vulnerable to contamination that counteracts their favorable growth and productivity. We applied the model to three different discharge scenarios to explore possible optimal operations that could reduce the influences. If the discharged volume rate is simply decreased at ∼16.7% relative to the baseline case that represents the actual operation, the effluent accumulating in the farm is reduced at ∼25.4% showing a significant nonlinearity. A tracer flux analysis demonstrated that the transient component accounting for fluctuating tides and eddies dominates over the time-averaged linear contribution to the effluent accumulation in the cross-shore effluent transport to the farm. By contrast, in the along-shore direction, the linear component leads to increased influx near the surface at the western transect of the farm, while the transient component is more essential to the overall reduction of the incoming tracer flux to the farm. On the other hand, density adjustment of the effluent for suppressing surfacing of buoyant effluent plume released from the bottom-mounted diffusers does not work well as expected, because pronounced far-field dilution takes over the near-source dilution affected by the density adjustment.

The MEGII Timing Counter will measure the positron time of arrival with a resolution of ~ 30 ps relying on two arrays of scintillator pixels read out by 6144 Silicon Photomultipliers (SiPMs) from AdvanSiD. They are characterised, measuring their breakdown voltage, to assure that the gains of the SiPMs of each pixel are as uniform as possible, to maximise the pixel resolution. Gain measurements have also been performed.

The development of a Timing Counter detector designed for the MEGII upgrade of the MEG experiment, which strives to improve the sensitivity on the μ + → e + γ decay of an order of magnitude, is presented. It is based on two sets of counters (sectors) arranged on a semi-cylindrical structure; each sector consists of 256 counters. Each counter consists of tile of fast scintillator with a dual-side read-out based on SiPM arrays in series connection. The high granularity has two advantages: optimized size for achieving high resolution (75 ps) for the single counter, and a signal e + crosses several counters, so that resolution improves by averaging multiple time measurements. A prototype has been built and tested both in BTF and PSI facilities in order to prove the multi-hit scheme in MEG-like beam conditions. A 35 ps resolution with eight hits has been obtained with a e + beam at 100 kHz. The first sector will be tested in the MEG II pre-engineering run planned at the end of 2015.

The development of a Timing Counter detector with a resolution in the range of ≈ 30 ps will be presented. The detector was designed for the upgrade of the MEG II experiment looking for the μ+ → e+γ decay with an improved sensitivity of one order of magnitude with respect to the previous MEG setup. In this paper the design of the TC single pixel is explained together with the results obtained in beam tests.

A new timing detector measuring ~50 MeV/c positrons is under development for the MEG II experiment, aiming at a time resolution $\sigma_t \sim 30~\mathrm{ps}$. The resolution is expected to be achieved by measuring each positron time with multiple counters made of plastic scintillator readout by silicon photomultipliers (SiPMs). The purpose of this work is to demonstrate the time resolution for ~50 MeV/c positrons using prototype counters. Counters with dimensions of $90\times 40\times 5~\mathrm{mm}^3$ readout by six SiPMs (three on each $40\times 5~\mathrm{mm}^2$ plane) were built with SiPMs from Hamamatsu Photonics and AdvanSiD and tested in a positron beam at the DA$\Phi$NE Beam Test Facility. The time resolution was found to improve nearly as the square root of the number of counter hits. A time resolution $\sigma_t=26.2\pm1.3~\mathrm{ps}$ was obtained with eight counters with Hamamatsu SiPMs. These results suggest that the design resolution is achievable in the MEG II experiment., Comment: 12 pages, 18 figures. Published in NIM A

We are developing a new type of photon detector for an experiment to search for muons decaying into a positron and a gamma ray. In this experiment, the photon detector will utilize liquid xenon (Xe) as the scintillation material. Good transparency of the liquid Xe is required in order to gain the highest performance out of the detector. Impurities like water and oxygen must be removed efficiently for this purpose. We have developed a new purification system, dedicated to removing water from liquid Xe, by employing a cryogenic centrifugal pump and molecular sieves. The performance of the system is described in this article.

A 50-year-old man presented with a 2-month history of dysarthria caused by a partially thrombosed vertebral artery (VA) aneurysm. Magnetic resonance imaging showed enhancement of the thickened wall and angiography detected staining. Stent-assisted coil embolization with protection of the parent artery patency was performed. The patient's clinical course was unremarkable and shrinking of the aneurysm was obtained. The stent-assisted coil embolization promoted intra-aneurysm flow disruption and stabilized the wall environment, suggesting another strategy for the treatment of partially thrombosed VA aneurysm.

The design and tests of Timing Counter elements for the upgrade of the MEG experiment, MEG II,is presented. The detector is based on several small plates of scintillator with a Silicon PhotoMultipliers dual-side readout. The optimisation of the single counter elements (SiPMs, scintillators, geometry) is described. Moreover, the results obtained with a first prototype tested at the Beam Test Facility (BTF) of the INFN Laboratori Nazionali di Frascati (LNF) are presented., 10 pages, 7 figures. Presented at the 13th Topical Seminar on Innovative Particle and Radiation Detectors (IPRD13) 7-10 October 2013 Siena, Italy

We present a development of scintillation counter system for a precise time measurement in the MEG II experiment searching for the lepton-flavor-violating decay, μ+ → e+γ. It consists of several hundreds of plastic scintillation counters each of which is read out by several silicon-photomultipliers (SiPM). To pursue the ultimate resolution of a single counter, we have studied and optimized types of SiPM and the way of connection, resulting in a single counter resolution of 40 ps. As a whole system, we achieve 30 ps resolution by combining several counter measurements. The resolution was demonstrated in a beam test.

We are developing Pixelated Photon Detector (PPD) sensitive to deep UV scintillation photons of liquid xenon as a possible candidate for the photosensor upgrade of the MEG liquid xenon γ-ray detector. The prototypes of the PPD preliminarily optimized for the detection of deep UV photons were tested in LXe and their basic properties were measured. The measured performance of the prototypes is described.

MEG experiment searches for new physics like SUSY-GUT/SUSY-seesaw through the lepton flavor violating μ → eγ decay. The current MEG experiment utilizes 846 2 inch PMTs in order to detect scintillation light in 900 l liquid xenon gamma-ray calorimeter. R&D of Pixelated Photon Detector (PPD) have been actively performed in many different fields as a new novel silicon photon detector, and we started developing a new type of PPD which is sensitive to liquid xenon scintillation light (175nm wavelength) as one of possible candidates of MEG detector upgrade plan in collaboration with Hamamatsu Photonics. Basic characteristics of these samples such as photon detection efficiency(PDE), gain, dark rate, cross talk, after pulse, pulse rise time/fall time, timing resolution, linearity etc. are being measured in a small setup in PSI with 2 l liquid xenon, refrigerator, and 241Am source. Preliminary result already shows 10% PDE in liquid xenon. These results and further optimization of MPPC parameters as well as possible prototype plan are described here.

Discussions have hardly been made on the plan of inhabited district on the so called super levee from the viewpoint of considering flood disaster prevention.In this paper, basic ideas of newly inhabited district constructed on the super levee are proposed for accomplishing both functions of dissipating the energy of the flow of overtopping flood water and that of good living circumstances. Severalplans of the arrangement of tall buildings, houses and streets to properly dissipate the energy of overtopping flood flow are shown here according to the policy to haveoverflow water concentrated on streets or not.

Summary Aim: To examine the utility of 2'-[18F]-fluoro-2'-deoxy-D-glucose positron emission tomography (FDG-PET) for detecting multiple primary cancers (MPC) in patients with hypopharyngeal cancer (HPC). Patients, methods: Seventy patients with HPC underwent FDGPET to determine the staging. Routine clinical examinations were carried out, including computed tomography (CT), magnetic resonance imaging (MRI), ultrasound (US), and oesophagealgastroduodenoscopy (EGDS). The detection rate of synchronous and metachronous cancer was calculated based on FDG-PET alone or FDG-PET combined with clinical routine examination. Sensitivity, specificity, positive predictive values (PPV), negative predictive values (NPV), and accuracy were used to diagnose oesophageal cancer using FDG-PET. Results: Of the 70 patients, 12 (17.1%) had 15 synchronous tumours, and 2 of the 58 remaining patients (3.4%) had metachronous tumours. Oesophageal cancer was discovered most frequently: superficial type (n = 6), advanced type (n = 4). On a per-patient basis, 11 of 12 patients (91.6%) were diagnosed with synchronous tumours, and on a per-lesion basis, 12 of 15 lesions (80.0%) were detected by FDG-PET. The sensitivity, specificity, accuracy, PPV, and NPV of FDG-PET regarding oesophageal cancer were 70%, 100%, 95.7%, 100%, and 95.2% respectively. Three of the six superficial types were positive on FDG-PET. Both of the metachronous tumour lesions were detected by FDG-PET. Conclusion: FDG-PET is useful for estimating the MPC in HPC patients. Since 3 of 10 synchronous oesophageal cancer were missed with PET alone, a combination with EGDS should be considered to exclude synchronous oesophageal cancer.

This study was performed to investigate the role of injection methods and conditions under a fixed dose of radiographic contrast medium (CM) in respect to promoting blood-brain barrier (BBB) disruption.A total of 44 white rabbits (average body weight 2.7 +/- 0.4 kg) were used, and their carotid injection was performed with nonionic CM. The variables assessed for the carotid injections included the following: iodine content (300 or 150 mg I/ml), liquid temperature (37 degrees or 24 degrees C), and the injection time duration (1 or 30 s). The rabbits were divided into five groups. To evaluate BBB disruption, pre- and post-contrast-enhanced magnetic resonance (MR) studies were performed.Abnormal enhancement of the brain parenchyma in MRI was noted in only one group, which consisted of high-iodine concentration CM injected at a low temperature over a short injection interval. Statistically significant increased values for the percentage of relative enhancement (RE%) were demonstrated (P0.05) in comparison with the saline-injected control group.This result suggests variables that may need to be carefully considered to prevent BBB injury induced by nonionic CM for cerebral angiography, especially in the setting of a neurointerventional procedure.