Search for the Pair Production of Dark Particles X with K_{L}

We present the first search for the pair production of dark particles X via K_{L}^{0}→XX with X decaying into two photons using the data collected by the KOTO experiment. No signal was observed in the mass range of 40-110 MeV/c^{2} and 210-240 MeV/c^{2}. This sets upper limits on the branching fractions as B(K_{L}^{0}→XX)<(1-4)×10^{-7} and B(K_{L}^{0}→XX)<(1-2)×10^{-6} at the 90% confidence level for the two mass regions, respectively.

Study of the K_{L}→π

The rare decay K_{L}→π^{0}νν[over ¯] was studied with the dataset taken at the J-PARC KOTO experiment in 2016, 2017, and 2018. With a single event sensitivity of (7.20±0.05_{stat}±0.66_{syst})×10^{-10}, three candidate events were observed in the signal region. After unveiling them, contaminations from K^{±} and scattered K_{L} decays were studied, and the total number of background events was estimated to be 1.22±0.26. We conclude that the number of observed events is statistically consistent with the background expectation. For this dataset, we set an upper limit of 4.9×10^{-9} on the branching fraction of K_{L}→π^{0}νν[over ¯] at the 90% confidence level.

Parity and the risk of incident dementia: a COSMIC study.

AIMS: To investigate the association between parity and the risk of incident dementia in women. METHODS: We pooled baseline and follow-up data for community-dwelling women aged 60 or older from six population-based, prospective cohort studies from four European and two Asian countries. We investigated the association between parity and incident dementia using Cox proportional hazards regression models adjusted for age, educational level, hypertension, diabetes mellitus and cohort, with additional analysis by dementia subtype (Alzheimer dementia (AD) and non-Alzheimer dementia (NAD)). RESULTS: Of 9756 women dementia-free at baseline, 7010 completed one or more follow-up assessments. The mean follow-up duration was 5.4 ± 3.1 years and dementia developed in 550 participants. The number of parities was associated with the risk of incident dementia (hazard ratio (HR) = 1.07, 95% confidence interval (CI) = 1.02-1.13). Grand multiparity (five or more parities) increased the risk of dementia by 30% compared to 1-4 parities (HR = 1.30, 95% CI = 1.02-1.67). The risk of NAD increased by 12% for every parity (HR = 1.12, 95% CI = 1.02-1.23) and by 60% for grand multiparity (HR = 1.60, 95% CI = 1.00-2.55), but the risk of AD was not significantly associated with parity. CONCLUSIONS: Grand multiparity is a significant risk factor for dementia in women. This may have particularly important implications for women in low and middle-income countries where the fertility rate and prevalence of grand multiparity are high.

Search for K_{L}→π

A search for the rare decay K_{L}→π^{0}νν[over ¯] was performed. With the data collected in 2015, corresponding to 2.2×10^{19} protons on target, a single event sensitivity of (1.30±0.01_{stat}±0.14_{syst})×10^{-9} was achieved and no candidate events were observed. We set an upper limit of 3.0×10^{-9} for the branching fraction of K_{L}→π^{0}νν[over ¯] at the 90% confidence level (C.L.), which improved the previous limit by almost an order of magnitude. An upper limit for K_{L}→π^{0}X^{0} was also set as 2.4×10^{-9} at the 90% C.L., where X^{0} is an invisible boson with a mass of 135 MeV/c^{2}.

Exposure to second-hand tobacco smoke and respiratory symptoms in non-smoking adults: cross-sectional data from the general population of Telemark, Norway.

BACKGROUND: In Norway, data on the association between second-hand tobacco smoke (SHS) exposure at home and respiratory symptoms in adults are limited. METHODS: We assessed the association between self-reported exposure to SHS and the prevalence of respiratory symptoms among never-smokers aged 16 to 50 years from the general population who were included in a cross-sectional population-based study in Telemark County, Norway. Logistic regression analysis was used to estimate the odds ratios of symptoms among 8850 never-smokers who provided an affirmative response to questions regarding SHS; 504 (5.7%) of these reported that they lived in a home with daily or occasional indoor smoking. RESULTS: Productive cough and nocturnal dyspnoea were statistically associated with daily SHS exposure (ORs 1.5 [95% CI 1.04-2.0] and 1.8 [1.2-2.7], respectively). In analyses stratified by gender, nocturnal dyspnoea was associated with SHS among women (OR 1.8 [1.1-3.1]), but not among men (OR 0.93 [0.49-1.8]). Symptoms were not associated with occasional SHS exposure in the entire group, but infrequent exposure among men only was associated with increased prevalence of chronic cough; (OR 1.6; [1.04-2.6]) and was negatively associated with wheeze; (OR 0.44 [0.21-0.92)]. CONCLUSIONS: Daily SHS exposure in private homes was associated with productive cough and nocturnal dyspnoea. Our results suggest that preventive measures may be needed to reduce the respiratory effects of SHS at home. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02073708 Registered February 27. 2014.

TACC3 deregulates the DNA damage response and confers sensitivity to radiation and PARP inhibition.

Deregulation of the transforming acidic coiled-coil protein 3 (TACC3), an important factor in the centrosome-microtubule system, has been linked to a variety of human cancer types. We have recently reported on the oncogenic potential of TACC3; however, the molecular mechanisms by which TACC3 mediates oncogenic function remain to be elucidated. In this study, we show that high levels of TACC3 lead to the accumulation of DNA double-strand breaks (DSBs) and disrupt the normal cellular response to DNA damage, at least in part, by negatively regulating the expression of ataxia telangiectasia mutated (ATM) and the subsequent DNA damage response (DDR) signaling cascade. Cells expressing high levels of TACC3 display defective checkpoints and DSB-mediated homologous recombination (HR) and non-homologous end joining (NHEJ) repair systems, leading to genomic instability. Importantly, high levels of TACC3 confer cellular sensitization to radiation and poly(ADP-ribose) polymerase (PARP) inhibition. Overall, our findings provide critical information regarding the mechanisms by which TACC3 contributes to genomic instability, potentially leading to cancer development, and suggest a novel prognostic, diagnostic and therapeutic strategy for the treatment of cancer types expressing high levels of TACC3.

Response of six neutron survey meters in mixed fields of fast and thermal neutrons.

Calibration neutron fields have been developed at KAERI (Korea Atomic Energy Research Institute) to study the responses of commonly used neutron survey meters in the presence of fast neutrons of energy around 10 MeV. The neutron fields were produced by using neutrons from the (241)Am-Be sources held in a graphite pile and a DT neutron generator. The spectral details and the ambient dose equivalent rates of the calibration fields were established, and the responses of six neutron survey meters were evaluated. Four single-moderator-based survey meters exhibited an under-responses ranging from ∼9 to 55 %. DINEUTRUN, commonly used in fields around nuclear reactors, exhibited an over-response by a factor of three in the thermal neutron field and an under-response of ∼85 % in the mixed fields. REM-500 (tissue-equivalent proportional counter) exhibited a response close to 1.0 in the fast neutron fields and an under-response of ∼50 % in the thermal neutron field.

Detection of residual brain arteriovenous malformations after radiosurgery: diagnostic accuracy of contrast-enhanced four-dimensional MR angiography at 3.0 T.

OBJECTIVE: To evaluate the diagnostic accuracy of four-dimensional MR angiography (4D-MRA) at 3.0 T for detecting residual arteriovenous malformations (AVMs) after Gamma Knife (Elekta Instrument AB, Stockholm, Sweden) radiosurgery (GKRS). METHODS: We assessed 36 angiographically confirmed AVMs in 36 patients who had been treated with GKRS. 4D-MRA was performed after GKRS and the time intervals were 39.4 ± 26.0 months [mean ± standard deviation (SD)]. 4D-MRA was obtained at 3.0 T after contrast injection, with a measured voxel size of 1 × 1 × 1 mm and a temporal resolution of 1.1 s (13 patients) or a voxel size of 1 × 1 × 2 mm and a temporal resolution of 0.98 s (23 patients). X-ray angiography was performed as the standard reference within 53 ± 47 days (mean ± SD) after MRA. To determine a residual AVM, the 4D-MRA results were independently reviewed by two readers blinded to the X-ray angiography results. We evaluated diagnostic sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 4D-MRA for detection of a residual AVM. RESULTS: A residual AVM was identified in 13 patients (13/36, 36%) on X-ray angiography. According to Readers 1 and 2, 4D-MRA had a sensitivity of 79.6% and 64.3%, a specificity of 90.9% and 100%, a PPV of 84.6% and 100% and an NPV of 90% and 81.5%, respectively, and a diagnostic accuracy of 86.1% for Readers 1 and 2, for detecting residual AVMs after GKRS. CONCLUSION: The diagnostic accuracy of 4D-MRA at 3.0 T seems high, but there is still the possibility of further improving the spatiotemporal resolution of this technique.

Incidence and prevalence of chronic bronchitis: impact of smoking and welding. The RHINE study.

OBJECTIVE: To investigate the prevalence and incidence rate of chronic bronchitis (CB) in relation to smoking habits and exposure to welding fumes in a general population sample. METHODS: Subjects from Northern Europe born between 1945 and 1971 who participated in Stage 1 (1989-1994) of the European Community Respiratory Health Survey were mailed a respiratory questionnaire in 1999-2001 (the RHINE study); 15,909 answered the questionnaire and gave complete data on smoking. CB was defined as chronic productive cough of at least 3 months a year for 2 consecutive years. The questionnaire comprised an item about age when CB started and items about exposure to welding fumes. The incidence of CB was retrospectively assessed for the observation period 1980-2001. RESULTS: CB had a prevalence of 5.4%, and was associated with current smoking and welding exposure. The incidence rate of CB was 1.9 per 1000 person-years, and was increased in relation to welding exposure (low exposure HR 1.4, 95%CI 1.1-1.8; high exposure HR 2.0, 95%CI 1.6-2.7) and in relation to smoking (HR 2.1, 95%CI 1.8-2.5). CONCLUSION: Smoking and occupational exposure to welding fumes are both associated with an increased risk of CB.

Carotid baroreceptor reaction after stenting in 2 locations of carotid bulb lesions of different embryologic origin.

BACKGROUND AND PURPOSE: The carotid bulb is innervated by the sinus nerve of Hering, a branch of the glossopharyngeal nerve, derived from the third pharyngeal arch. The aim of this study was to determine the frequency, predictors, and outcome of the carotid BR after carotid stent placement according to the location of the plaque lesion. MATERIALS AND METHODS: Atherosclerotic carotid plaques of apical versus body lesions were prospectively analyzed in 95 consecutive patients who underwent carotid stent placement. Patients with hypertension after stent placement were excluded, and transient (<3 hours) and prolonged (3-24 hours) BR, together with AEs such as strokes and death, were assessed in the 2 lesion locations (apical versus body). Other factors known to affect the carotid baroreceptor were also investigated, and the results were analyzed by χ(2) or Mann-Whitney U tests. RESULTS: Transient BR occurred in 30% of apical lesions in contrast to 70% of body lesions (P = .001). Transient BR showed a significant relationship to lesion location (P = .001), occurring most frequently in body lesions, and to the distance of maximum stenosis from the ICA ostium (P = .001). Hyperperfusion and AE rates (P = .076) in 1 month occurred more frequently in apical lesions. CONCLUSIONS: The frequency of transient BR after carotid stent placement was lower in the apical region of the carotid bulb. Different cardiovascular disturbances after carotid stent placement can be attributed to anatomically different areas of the carotid bulb.

MR diagnosis of facial neuritis: diagnostic performance of contrast-enhanced 3D-FLAIR technique compared with contrast-enhanced 3D-T1-fast-field echo with fat suppression.

BACKGROUND AND PURPOSE: Current MRI with the CE T1-weighted sequence plays a limited role in the evaluation of facial neuritis due to prominent normal facial nerve enhancement. Our purpose was to retrospectively investigate the usefulness of the CE 3D-FLAIR sequence compared with the CE 3D-T1-FFE sequence in facial neuritis patients. MATERIALS AND METHODS: We assessed 36 consecutive patients who underwent temporal bone MR imaging at 3T for idiopathic facial palsy. Two readers independently reviewed CE 3D-T1-FFE and CE 3D-FLAIR images to determine the degree of enhancement in each of 5 segments of the facial nerve. We compared AUCs using the Z-test, compared diagnostic performance of 2 MR techniques with the McNemar test, and evaluated interobserver agreement. The Pearson χ(2) test was used for each segment of the facial nerve. RESULTS: The AUC of CE 3D-FLAIR (reader 1, 0.754; reader 2, 0.746) was greater than that of CE 3D-T1-FFE (reader 1, 0.624; reader 2, 0.640; P < .001). The diagnostic sensitivities, specificities, and accuracies were 97.2%, 86.1%, and 91.7%, respectively, for CE 3D-FLAIR, and 100%, 56.9%, and 78.5%, respectively, for CE 3D-T1-FFE. The specificity and accuracy of CE 3D-FLAIR were greater than those of CE 3D-T1-FFE (specificity, P = .029; accuracy, P = .008). The interobserver agreements for CE 3D-FLAIR (κ-value, 0.831) and CE 3D-T1-FFE (κ-value, 0.694) were excellent. Enhancement of the canalicular and anterior genu segments on CE 3D-FLAIR were significantly correlated with the occurrence of facial neuritis (P < .001 for canalicular; P = .032 and 0.020 for anterior genu by reader 1 and reader 2, respectively). CONCLUSIONS: CE 3D-FLAIR can improve the specificity and overall accuracy of MR imaging in patients with idiopathic facial palsy.

Outcomes after endovascular treatment of symptomatic patients with Takayasu's arteritis.

We report our experience with endovascular treatment of supra-aortic arteries and follow-up results in patients with Takayasu's arteritis (TA) presenting with neurological symptoms. Of the 20 patients with TA who underwent cerebral angiography for neurological manifestations between May 2002 and May 2009, 12 (11 females, one male; mean age, 39 years; range 31-56 years) underwent endovascular treatment and evaluated outcome for 21 lesions, including nine common carotid arteries, four vertebral arteries, four subclavian arteries, two internal carotid arteries, and one brachiocephalic artery. Eight patients underwent multiple endovascular procedures for different lesions in single or multiple stages. Mean angiographic and clinical follow-up durations were 34 months (range, 11-79 months) and 39 months (range 11-91 months), respectively. Technical success was achieved for 20 procedures in 11 patients. One procedure failed, with 50% residual stenosis after stenting due to dense calcification of vessel walls. There were no procedure-related complications. Restenosis occurred at two lesions in two patients were treated by re-stenting. Asymptomatic occlusion occurred at two lesions in one patient. Ten patients remained in 0-1 on the modified Rankin scale (mRs) during mean 39 months. One patient, however, had a score of 3 on mRs due to a traumatic contusion during follow-up. One patient died from cardiac failure 36 months after successful angioplasty.Our data suggest that endovascular treatment of symptomatic supra-aortic lesions of TA is effective and durable in selected patients with neurologic symptoms.

Fish consumption and school grades in Swedish adolescents: a study of the large general population.

AIM: To study the associations between fish intake and academic achievement as cognitive parameter among Swedish adolescents. METHODS: In 2000, a questionnaire including respiratory items, socioeconomic conditions and dietary information was mailed to all schoolchildren (n = 18 158), aged 15 and living in Västra Götaland region of Sweden. The questionnaire was returned by 10 837 subjects. One year later, the total school grades for each subject who had completed the questionnaire and who included their full personal identification number were obtained from the national registers. Multiple linear regression models were applied to evaluate the association between fish intake and academic grades among 9448 schoolchildren, while adjusting for potential confounders, e.g. parents' education. RESULTS: Grades were higher in subjects with fish consumption once a week compared with subjects with fish consumption of less than once a week (reference group) [increment in estimate 14.5, 95% confidence interval (CI) 11.8-17.1]. Grades were even higher in subjects with fish consumption of more than once a week compared with the reference group (increment in estimate 19.9, 95% CI 16.5-23.3). In the model stratified for parents' education, there were still higher grades among subjects with frequent fish intake in all educational strata (p < 0.01). CONCLUSION: Frequent fish intake among schoolchildren may provide benefits in terms of academic achievement.

Quantitative PCR analysis of fungal DNA in Swedish day care centers and comparison with building characteristics and allergen levels.

Abstract Sweden has had allergen-avoidance day care centers (AADCs) since 1979. The aim of this study was to measure fungal DNA by quantitative polymerase chain reaction (qPCR), a new method, in AADCs and ordinary day care centers (ODCs) and examine associations between allergen levels and building characteristics. Dust samples were collected by swabbing doorframes, vacuum-cleaning, and using Petri dishes. In total, 11 AADCs and 11 ODCs were studied (70 rooms). Total fungal DNA, measured by qPCR in the swab dust, was detected in 89%, Aspergillus or Penicillium (Asp/Pen) DNA in 34%, and Stachybotrys chartarum DNA in 6% of the rooms. Total fungal DNA was significantly higher in rooms with linoleum floor (P = 0.02), textile carpets (P = 0.03), reported dampness/molds (P = 0.02) and reported odor (P < 0.001) in the buildings, and significantly lower in wooden facade buildings (P = 0.003). Reported odor was related to the amount of sieved fine dust, reported dampness/molds and type of building construction. Total fungal DNA was related to cat, dog, horse and total allergen levels (P = 0.003) in the day care centers. In conclusion, total fungal DNA is related to reported dampness/molds, reported odor, and type of wall construction. The association between fungal and allergen contamination indicated a general 'hygiene factor' related to biological contaminants. Practical Implications The associations between fungal DNA, reported dampness/molds, and odor support the view that buildings with odor problems should be investigated for possible hidden fungal growth. There is a need to measure fungal biomass in different types of building constructions by monitoring fungal DNA. Analysis of fungal DNA with quantitative PCR can be a fast and practical way to study indoor fungal contamination. Swabbing dust from the doorframe of the main entrance to the room can be a convenient method of sampling dust for fungal DNA analysis. The high prevalence of reported dampness/molds and the common occurrence of fungal DNA indicate the need to improve the indoor environment of Swedish day care centers.

Further studies on higher temperature TL glow peaks of 7LiF:Mg,Ti.

Thermoluminescence (TL) characteristics of the higher temperature peaks of LiF:Mg,Ti, which exhibit a unique property of high relative response to high LET radiation, were studied in view of some recent findings and discussions. By making separate readouts of dosimetric peaks (mainly peak 5) and higher temperature peaks (mainly peak 7), the precision in TL measurements, reusability and, fading were found comparable for the TL readouts in the two regions. However, the intensity of higher temperature peaks was found to be susceptible to the annealing treatments. In the standard annealing treatment of LiF:Mg,Ti, namely, 400 degrees C for 1 h followed by 100 degrees C for 2 h, the intensity of the higher temperature glow peaks was significantly affected when the second step of lower temperature annealing treatment at 100 degrees C for 2 h was not used. The dose response function f(D) of higher temperature peaks to gamma rays in the range from 30 to 150 mGy was found to be within about 10% (-4 and +9%) but above 200 mGy it increased sharply. The intricacies of dosimetry of mixed fields of low and high LET radiation are discussed.

Development and validation of reverberation-chamber type whole-body exposure system for mobile-phone frequency.

We developed whole-body exposure systems for in-vivo study at cellular (848.5 MHz) and Personal Communication System (PCS, 1,762.5 MHz) frequency, utilizing reverberation chamber. The field uniformities in the test area of the designed chambers were verified by simulation and measurement. In the whole-body exposure environment, Specific Absorption Rate (SAR) distributions inside of mice were calculated using Finite Difference Time Domain (FDTD) simulation. Key results are presented in this article.

Recent developments of optically stimulated luminescence materials and techniques for radiation dosimetry and clinical applications.

During the last 10 years, optically stimulated luminescence (OSL) has emerged as a formidable competitor not only to thermoluminescence dosimetry (TLD) but also to several other dosimetry systems. Though a large number of materials have been synthesized and studied for OSL, Al(2)O(3):C continues to dominate the dosimetric applications. Re-investigations of OSL in BeOindicate that this material might provide an alternative to Al(2)O(3):C. Study of OSL of electronic components of mobile phones and ID cards appears to have opened up a feasibility of dosimetry and dose reconstruction using the electronic components of gadgets of everyday use in the events of unforeseen situations of radiological accidents, including the event of a dirty bomb by terrorist groups. Among the newly reported materials, a very recent development of NaMgF(3):Eu(2+) appears fascinating because of its high OSL sensitivity and tolerable tissue equivalence. In clinical dosimetry, an OSL as a passive dosimeter could do all that TLD can do, much faster with a better or at least the same efficiency; and in addition, it provides a possibility of repeated readout unlike TLD, in which all the dose information is lost in a single readout. Of late, OSL has also emerged as a practical real-time dosimeter for in vivo measurements in radiation therapy (for both external beams and brachytherapy) and in various diagnostic radiological examinations including mammography and CT dosimetry. For in vivo measurements, a probe of Al(2)O(3):C of size of a fraction of a millimeter provides the information on both the dose rate and the total dose from the readout of radioluminescence and OSL signals respectively, from the same probe. The availability of OSL dosimeters in various sizes and shapes and their performance characteristics as compared to established dosimeters such as plastic scintillation dosimeters, diode detectors, MOSFET detectors, radiochromic films, etc., shows that OSL may soon become the first choice for point dose measurements in clinical applications. A brief review of the recent developments is presented.