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BACKGROUND: Orbital apex syndrome (OAS) is a condition characterised by lesions within the orbital apex, leading to various ophthalmologic symptoms. This study aimed to analyse the clinical characteristics and treatment strategies of OAS with respect to aetiology. METHODS: This retrospective analysis utilised data from 5 medical institutions between 2013 and 2022. Patients who were diagnosed with OAS were initially enrolled, but patients who failed to follow up at least 1 month were excluded. The prevalence of initial ophthalmologic symptoms and visual improvement after treatment was compared according to aetiology. Factors related to visual improvement were analysed. RESULTS: Among 73 enrolled patients, the leading aetiology was tumours, followed by fungal infections and inflammation. Visual impairment and proptosis were prevalent in tumour-related OAS cases. Inflammation-related OAS exhibited a higher likelihood of painful eye movements and ophthalmoplegia. Ptosis was most frequently observed in fungal infection-related OAS. Notably, fungal infections emerged as the sole significant factor negatively impacting vision progression. In inflammation-related OAS, the time interval between symptom onset and the administration of steroids was longer in patients without visual improvement, even though there was no statistically significant difference. CONCLUSIONS: Tumours were the predominant cause of OAS. Visual impairment was a common manifestation in tumour-related OAS, while fungal infections were strongly associated with a poor visual prognosis. The timely administration of steroids might be helpful for improving vision in patients with inflammation-related OAS. However, further studies are needed to enhance understanding and management of OAS.
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OBJECTIVES: SARS-CoV-2 testing has been critical in monitoring and containing the COVID-19 pandemic, but there is a dearth of studies on how individuals' adherence to testing varies according to their working conditions. This study aimed to investigate the association between the type of employment contract and COVID-19 testing among wage workers in South Korea. STUDY DESIGN: We used a nationally representative sample of employees aged 20-65 years collected from March 24 to 31, 2022. To focus on individual responses when the test was recommended, our sample consisted of 1266 participants who had experienced symptoms of COVID-19 or had been exposed to a confirmed case in the household. METHODS: We used multivariate logistic regression to estimate the association between the odds of receiving a PCR test and the type of employment contract while controlling for other potential covariates. RESULTS: The percentage of participants who had a SARS-CoV-2 PCR test was 77.8%. After adjusting for all potential covariates, daily workers (OR = 0.35, 95% CI 0.18 to 0.70, P = 0.003) and part-time workers (OR = 0.58, 95% CI 0.39 to 0.86, P = 0.007) had significantly lower odds of being tested relative to standard workers. Other temporary or atypical workers showed no significant differences from standard workers. CONCLUSION: Our findings suggested that individuals in the most vulnerable job positions, with less job security and working hours, exhibited a decreased inclination to undergo COVID-19 testing. More effective job retention and income support policies are required to improve compliance.
Subject(s)
COVID-19 Testing , COVID-19 , Humans , Pandemics , COVID-19/diagnosis , COVID-19/epidemiology , SARS-CoV-2 , Employment , Republic of Korea/epidemiologyABSTRACT
PURPOSE: Oral treprostinil and selexipag are drugs targeting the prostacyclin pathway and are approved for treatment of pulmonary arterial hypertension (PAH). In the setting of unsatisfactory clinical response or tolerability issues while on selexipag, there is little data on clinical benefit, safety, or strategies on transitioning to oral treprostinil. Using prospective data from the ADAPT registry, we aimed to evaluate clinical outcomes, safety, and transition strategies in ten patients with PAH transitioning from selexipag to oral treprostinil. METHODS: ADAPT was a prospective, real-world, multicenter, United States-based registry of patients with PAH newly started on oral treprostinil, with a cohort of patients (n = 10) transitioning from selexipag to oral treprostinil. PAH variables of interest were collected from standard-of-care clinic visits. Clinical improvement was defined by modified REPLACE criterion, and risk was assessed by REVEAL Lite 2 from baseline to last follow-up. Real world transition strategies were recorded. Healthcare utilization or worsening PAH was evaluated within 30 days of transitions. RESULTS: Seven patients transitioned due to worsening PAH or lack of efficacy on selexipag, and three patients transitioned due to tolerability issues. Based on the modified REPLACE criterion, five patients demonstrated clinical improvement after transition from selexipag to oral treprostinil. Using REVEAL Lite 2 to assess risk, three patients improved and five patients maintained risk category from baseline to last follow-up. All transitions occurred in an outpatient setting either as abrupt stop/start or cross-titration, without parenteral treprostinil bridging. CONCLUSION: Transition from selexipag to oral treprostinil was safe, performed without parenteral prostacyclin bridging, and resulted in clinical and categorical risk improvements in some patients.
Subject(s)
Hypertension, Pulmonary , Pulmonary Arterial Hypertension , Humans , Pulmonary Arterial Hypertension/drug therapy , Antihypertensive Agents , Hypertension, Pulmonary/drug therapy , Prospective Studies , Administration, Oral , Epoprostenol/adverse effects , Familial Primary Pulmonary Hypertension/drug therapy , RegistriesABSTRACT
BACKGROUND: Identification of perioperative risk factors for recurrent nasal polyps (RNPs) is important for selection of further treatment and determination of appropriate follow-up period. However, the relative prognostic significance of these risk factors has not been investigated. METHODOLOGY: We compared the nasal symptoms, endoscopic polyp and Lund-Mackey computed tomography scores, and the laboratory and pathological findings of RNP and non-RNP patients. The risk of bias was assessed using the Newcastle-Ottawa scale. RESULTS: Patients with poor nasal symptom scores and olfactory dysfunctions and high Lund-Mackey computed tomography scores were at higher risk of postoperative RNPs, as were those with allergic conditions and elevated tissue and serum eosinophil levels. The tissue neutrophil counts/percentages were significantly lower in the RNP than the other group. The tissue eosinophil level was of higher diagnostic utility than the serum eosinophil level. The RNP diagnostic odds ratio afforded by the tissue eosinophil count or percentage was 54.1247. The area under the receiver operating characteristic curve was 0.936. The sensitivity and specificity were 0.8809 and 0.8834, respectively. CONCLUSION: The tissue eosinophil level reliably predicts RNP after endoscopic sinus surgery.
Subject(s)
Nasal Polyps , Rhinitis , Sinusitis , Humans , Nasal Polyps/complications , Nasal Polyps/surgery , Nasal Polyps/diagnosis , Rhinitis/complications , Rhinitis/surgery , Rhinitis/diagnosis , Sinusitis/complications , Sinusitis/surgery , Sinusitis/diagnosis , Eosinophils , Smell , Chronic DiseaseABSTRACT
AIM: To evaluate the reliability of synthetic diffusion-weighted imaging (DWI) using a high b-value in comparison to conventional DWI for paediatric abdominal MRI. MATERIALS AND METHODS: Paediatric patients (<19 years old) who underwent liver or pancreatobiliary MRI with DWI using 10 b-values (b = 0, 25, 50, 75, 100, 200, 400, 600, 800, 1,500 s/mm2) from March to October 2021 were included in this retrospective study. Using the software, synthetic DWI using b = 1,500 s/mm2 was generated automatically by selecting the b-value required as output. Conventional and synthetic DWI values for b = 1,500 s/mm2 were measured at the liver, spleen, paraspinal muscle, and mass lesions, if present, and apparent diffusion coefficient (ADC) values were calculated using the mono-exponential model. Intraclass correlation coefficients (ICCs) were calculated to assess the reliability of conventional and synthetic DWI and ADC values with b = 1,500 s/mm2. RESULTS: Thirty paediatric patients (M:F = 22:8, mean 10.8 ± 3.1 years old) were included and four had tumours on abdominal MRI. ICC values were 0.906-0.995 between conventional and synthetic DWI and ADC with b = 1,500 s/mm2 in the liver, spleen and muscle. For mass lesions, ICC values were 0.997-0.999 for both synthetic DWI and ADC images. CONCLUSIONS: Synthetic DWI and ADC values obtained using a high b-value showed excellent agreement with conventional DWI for the liver, spleen, muscle, and mass in paediatric MRI.
Subject(s)
Diffusion Magnetic Resonance Imaging , Neoplasms , Humans , Child , Young Adult , Adult , Adolescent , Retrospective Studies , Reproducibility of Results , Diffusion Magnetic Resonance Imaging/methods , Magnetic Resonance Imaging/methodsABSTRACT
BACKGROUND: Currently, there is no consensus on the number of defibrillation attempts that should be made before transfer to a hospital in patients with out-of-hospital cardiac arrest (OHCA). This study aimed to evaluate the association between the number of defibrillations and a sustained prehospital return of spontaneous circulation (ROSC). METHODS: A retrospective analysis of a multicentre, prospectively collected, registry-based study in Republic of Korea was conducted for OHCA patients with prehospital defibrillation. The primary outcome was sustained prehospital ROSC, and the secondary outcome was a good neurological outcome at hospital discharge, defined as Cerebral Performance Category score 1 or 2. Cumulative incidence of sustained prehospital ROSC and good neurological outcome according to number of defibrillations were examined. Multivariable logistic regression analysis was used to examine whether the number of defibrillations was independently associated with the outcomes. RESULTS: Excluding 172 patients with missing data, a total of 1983 OHCA patients who received prehospital defibrillation were included. The median time from arrest to first defibrillation was 10 (IQR 7-15) min. The numbers of patients with sustained prehospital ROSC and good neurological outcome were 738 (37%) and 549 (28%), respectively. Sustained ROSC rates decreased as the number of defibrillation attempts increased from the first to the sixth (16%, 9%, 5%, 3%, 2% and 1%, respectively). The cumulative sustained ROSC rate, and good neurological outcome rate from initial defibrillation to sixth defibrillation were 16%, 25%, 30%, 34%, 36%, 36% and 11%, 18%, 22%, 25%, 26%, 27%, respectively. With adjustment for clinical characteristics and time to defibrillation, a higher number of defibrillations was independently associated with a lower chance of a sustained ROSC (OR 0.81, 95% CI 0.76 to 0.86) and a lower chance of good neurological outcome (OR 0.86, 95% CI 0.80 to 0.92). CONCLUSIONS: We observed no significant increase in ROSC after five defibrillations, and no absolute increase in ROSC after seven defibrillations. These data provide a starting point for determination of the optimal defibrillation strategy prior to consideration for prehospital extracorporeal cardiopulmonary resuscitation (ECPR) or conveyance to a hospital with an ECPR capability. TRIAL REGISTRATION NUMBER: NCT03222999.
Subject(s)
Cardiopulmonary Resuscitation , Emergency Medical Services , Out-of-Hospital Cardiac Arrest , Humans , Retrospective Studies , Return of Spontaneous Circulation , RegistriesABSTRACT
OBJECTIVE: To perform a systematic review of case reports or case series regarding thrombosis with thrombocytopenia syndrome (TTS) and cerebral venous thrombosis (CVT) related to ChAdOx1 nCoV-19 vaccination to address the clinical features, laboratory findings, treatment modalities, and prognosis related with CVT. SUBJECTS AND METHODS: We included 64 TTS patients from 19 articles, 6 case series and 13 case reports, in which thrombosis occurred after the first dose of ChAdOx1 nCoV-19 vaccination published up to 30 June 2021 in Embase, ePubs, Medline/PubMed, Scopus, and Web of Science databases. RESULTS: Of the 64 TTS patients, 38 (59.3%) had CVT. Patients with CVT were younger (median 36.5 vs. 52.5 years, p<0.001), had lower fibrinogen levels (130 vs. 245 mg/dL, p=0.008), had more frequent history of intracerebral hemorrhage (ICH), and had higher mortality rate (48.6% vs. 19.2%, p=0.020) than that of patients without CVT. In multivariable analysis, the possibility of presence of CVT was higher in younger age groups [odd ratio (OR): 0.91, 95% confidence interval (CI): (0.86-0.97, p<0.001)] and those with accompanying intracerebral hemorrhage (ICH) (OR: 13.60, 95% CI (1.28-144.12, p=0.045). CONCLUSIONS: Our study demonstrated that CVT related to ChAdOx1 nCoV-19 vaccination was associated with younger age, low levels of fibrinogen, presence of ICH and more frequent mortality compared to those of non-CVT. If TTS occurs after ChAdOx1 nCoV-19 vaccination, the presence of CVT in patients with young age or ICH should be considered.
Subject(s)
ChAdOx1 nCoV-19 , Intracranial Thrombosis , Venous Thrombosis , Humans , Cerebral Hemorrhage/complications , ChAdOx1 nCoV-19/adverse effects , Fibrinogen , Intracranial Thrombosis/chemically induced , Risk Factors , Vaccination/adverse effects , Venous Thrombosis/chemically inducedABSTRACT
Identifying factors associated with persistent pain after breast cancer surgery may facilitate risk stratification and individualised management. Single-population studies have limited generalisability as socio-economic and genetic factors contribute to persistent pain development. Therefore, this prospective multicentre cohort study aimed to develop a predictive model from a sample of Asian and American women. We enrolled women undergoing elective breast cancer surgery at KK Women's and Children's Hospital and Duke University Medical Center. Pre-operative patient and clinical characteristics and EQ-5D-3L health status were recorded. Pain catastrophising scale; central sensitisation inventory; coping strategies questionnaire-revised; brief symptom inventory-18; perceived stress scale; mechanical temporal summation; and pressure-pain threshold assessments were performed. Persistent pain was defined as pain score ≥ 3 or pain affecting activities of daily living 4 months after surgery. Univariate associations were generated using generalised estimating equations. Enrolment site was forced into the multivariable model, and risk factors with p < 0.2 in univariate analyses were considered for backwards selection. Of 210 patients, 135 (64.3%) developed persistent pain. The multivariable model attained AUC = 0.807, with five independent associations: age (OR 0.85 95%CI 0.74-0.98 per 5 years); diabetes (OR 4.68, 95%CI 1.03-21.22); pre-operative pain score at sites other than the breast (OR 1.48, 95%CI 1.11-1.96); previous mastitis (OR 4.90, 95%CI 1.31-18.34); and perceived stress scale (OR 1.35, 95%CI 1.01-1.80 per 5 points), after adjusting for: enrolment site; pre-operative pain score at the breast; pre-operative overall pain score at rest; postoperative non-steroidal anti-inflammatory drug use; and pain catastrophising scale. Future research should validate this model and evaluate pre-emptive interventions to reduce persistent pain risk.
Subject(s)
Breast Neoplasms , Child , Humans , Female , Child, Preschool , Breast Neoplasms/surgery , Prospective Studies , Cohort Studies , Activities of Daily Living , Pain , Risk Factors , Pain, Postoperative/epidemiology , Pain, Postoperative/etiology , Pain, Postoperative/diagnosisABSTRACT
OBJECTIVE: This study aimed to compare the prognostic utility of sentinel node biopsy and elective neck dissection in early stage clinically node-negative oral cavity squamous cell carcinoma patients. METHOD: PubMed, Scopus, Embase, Web of Science and Cochrane Library databases were searched up to March 2022. Hazard ratios, Kaplan-Meier curves, p-values and survival outcomes were extracted. RESULTS: Twelve studies involving 10 583 patients were included. No significant differences in overall survival between sentinel node biopsy and elective neck dissection groups were found. Heterogeneity was not detected in pooled overall survival, disease-free survival and disease-specific survival analyses (all I2 less than 50). In subgroup analyses by follow-up period, sentinel node biopsy and elective neck dissection had similar prognostic value. CONCLUSION: Sentinel node biopsy might be a valuable alternative to elective neck dissection for the management of early stage clinically node-negative oral cavity squamous cell carcinoma.
Subject(s)
Carcinoma, Squamous Cell , Head and Neck Neoplasms , Mouth Neoplasms , Humans , Sentinel Lymph Node Biopsy , Neck Dissection , Squamous Cell Carcinoma of Head and Neck/surgery , Squamous Cell Carcinoma of Head and Neck/pathology , Neoplasm Staging , Head and Neck Neoplasms/pathology , Lymph Nodes/surgery , Lymph Nodes/pathologyABSTRACT
BACKGROUND: High rates of physical and mental health comorbidities are associated with functional impairment among persons who are homeless. Cognitive dysfunction is common, but how it contributes to various functional outcomes in this population has not been well investigated. This study examines how cognition covaries with community functioning and subjective quality of life over a 6-year period while accounting for the effects of risk and protective factors. METHODS: Participants were 349 homeless adults (mean age = 39.8) recruited from the Toronto site of the At Home/Chez Soi study, a large Canadian randomized control trial of Housing First. Participants completed up to four clinical evaluations over 6 years. Factor scores were created to index verbal learning and memory (vLM) and processing speed-cognitive flexibility (PSCF). The primary outcomes were community functioning and subjective quality of life. Risk factors included lifetime homelessness, mental health diagnoses, medical comorbidity, and childhood adversity. Linear mixed-effects models were conducted to examine cognition-functional outcome associations over time, with resilience as a moderator. RESULTS: Better vLM (b = 0.787, p = 0.010) and PSCF (b = 1.66, p < 0.001) were associated with better community functioning, but not with quality of life. Resilience conferred a protective effect on subjective quality of life (b = 1.45, p = 0.011) but did not moderate outcomes. CONCLUSIONS: Our findings suggest a need to consider the unique determinants of community functioning and quality of life among homeless adults. Cognition should be prioritized as a key intervention target within existing service delivery models to optimize long-term functional outcomes.
Subject(s)
Ill-Housed Persons , Mental Disorders , Adult , Humans , Quality of Life , Follow-Up Studies , Canada/epidemiology , Mental Disorders/psychology , CognitionABSTRACT
A microporous continuum traversed by a set of mutually perpendicular channels is considered to be a model for a hierarchically porous system of the mesoporous zeolite type. Transient profiles of molecular uptake as determined by kinetic Monte Carlo (kMC) simulation are found to be in excellent agreement with the result attained by the application of the two-region model (the Kärger model) of molecular diffusion. In particular, it is found that, in the two limiting cases referred to as fast exchange and slow exchange, there exist two simple analytical expressions for the rate of molecular uptake and hence for the quantification of transport enhancement in comparison with the purely microporous adsorbent. In the general case, transport enhancement is simply recognized by the reciprocal addition of the expressions in the two limiting cases.
Subject(s)
Zeolites , Computer Simulation , Diffusion , Kinetics , Monte Carlo MethodABSTRACT
Although accurate intracranial pressure (ICP) monitoring is essential for the diagnosis and treatment of severe brain diseases, current methods are performed invasively. Therefore, a safe and less invasive ICP measurement is required. The purpose of our study was to develop a simplified cranial cavity model for a better understanding of the relationship between the ICP and the pressure measurement within the dural venous sinus (DVS) to support the validity of using sinus pressure as the surrogate of the ICP. The in-house cranial cavity model had three components: the brain part, the DVS part, and the subarachnoid space (SAS) part. Pressure in other parts was measured when the pressure in the SAS part and, separately, brain part was increased from 0 (baseline) to 50 mmHg at intervals of 10 mmHg. When the pressure in the SAS part was increased from 10 to 50 mmHg at 10 mmHg interval, pressures of both the brain and DVS parts increased without significant difference (all P > 0.05). However, pressures in both the SAS and DVS parts differed while the pressure in the brain part was increased. The pressures in both parts showed about 70% of the increase in the brain part. Nevertheless, the pressures in the SAS and DVS parts were not significantly different (P > 0.05). A simplified in-house cranial cavity model was developed consisting of three compartments to represent the actual intracranial spaces. The pressure measurement within the DVS was feasible to use as a surrogate for the ICP measurement.
ABSTRACT
The 129I standardization, using the movable 4πß(LS)-X(NaI(Tl)) coincidence system, was performed for two 129I radioactive sources - one was dissolved in 0.1M NaOH solution and the other in 0.1M HNO3 solution. The system incorporates three movable PM tubes for a ß-counter placed on a plane and a X-ray detector that can be moved up to the bottom of the vial. The ß-efficiency depending on the amount of radioactive solution was investigated with 14 liquid scintillation samples prepared by gravimetrically dispensing 4.4-145 mg of 129I radioactive solution. The ß-efficiencies above 90% were observed at less than 56 mg, but it was at most 70% at 145 mg. This occurred regardless of the activity of the sample or the type of chemical solution used to dissolve 129I source. The activity concentration of each 129I source was determined by efficiency-extrapolation method for samples with an activity range of 0.28-4.5 kBq. The ß-efficiency points were derived over 10 intervals by moving 3-PM tubes in fine steps of about 1 mm from the sample. The highest value for ß-efficiency was 95%. The combined uncertainty were 0.25% and 0.26%, respectively. The stated precision obtained using the system is better than that previously reported in the literature obtained by the triple to double coincidence ratio (TDCR) or the CIEMAT/NIST efficiency tracing method.
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Asymmetric spin wave excitation and propagation are key properties to develop spin-based electronics, such as magnetic memory, spin information and logic devices. To date, such nonreciprocal effects cannot be manipulated in a system because of the geometrical magnetic configuration, while large values of asymmetry ratio are achieved. In this study, we suggest a new magnetic system with two blocks, in which the asymmetric intensity ratio can be changed between 0.276 and 1.43 by adjusting the excitation frequency between 7.8 GHz and 9.4 GHz. Because the two blocks have different widths, they have their own spin wave excitation frequency ranges. Indeed, the spin wave intensities in the two blocks, detected by the Brillouin light scattering spectrum, were observed to be frequency-dependent, yielding tuneable asymmetry ratio. Thus, this study provides a new path to enhance the application of spin waves in spin-based electronics.
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BACKGROUND AND PURPOSE: Posterior fossa type A (PFA) ependymomas have 2 molecular subgroups (PFA-1 and PFA-2) and 9 subtypes. Gene expression profiling suggests that PFA-1 and PFA-2 tumors have distinct developmental origins at different rostrocaudal levels of the brainstem. We, therefore, tested the hypothesis that PFA-1 and PFA-2 ependymomas have different anatomic MR imaging characteristics at presentation. MATERIALS AND METHODS: Two neuroradiologists reviewed the preoperative MR imaging examinations of 122 patients with PFA ependymomas and identified several anatomic characteristics, including extension through the fourth ventricular foramina and encasement of major arteries and tumor type (midfloor, roof, or lateral). Deoxyribonucleic acid methylation profiling assigned ependymomas to PFA-1 or PFA-2. Information on PFA subtype from an earlier study was also available for a subset of tumors. Associations between imaging variables and subgroup or subtype were evaluated. RESULTS: No anatomic imaging variable was significantly associated with the PFA subgroup, but 5 PFA-2c subtype ependymomas in the cohort had a more circumscribed appearance and showed less tendency to extend through the fourth ventricular foramina or encase blood vessels, compared with other PFA subtypes. CONCLUSIONS: PFA-1 and PFA-2 ependymomas did not have different anatomic MR imaging characteristics, and these results do not support the hypothesis that they have distinct anatomic origins. PFA-2c ependymomas appear to have a more anatomically circumscribed MR imaging appearance than the other PFA subtypes; however, this needs to be confirmed in a larger study.
Subject(s)
Ependymoma , Infratentorial Neoplasms , Cohort Studies , Ependymoma/diagnostic imaging , Ependymoma/genetics , Ependymoma/pathology , Humans , Infratentorial Neoplasms/diagnostic imaging , Magnetic Resonance Imaging , NeuroimagingSubject(s)
COVID-19 , Ill-Housed Persons , COVID-19 Vaccines , Canada , Humans , SARS-CoV-2 , United Kingdom , VaccinationABSTRACT
Parametric pumping is a nonlinear wave phenomenon and a promising technique for electronic devices based on spin waves, so-called "magnonics". For parametric excitation, a magnetic nanowire system that has a built-in dc current line to produce an Oersted field is designed, and for spin wave detection, a micro-Brillouin light scattering (µ-BLS) system is used. A spin wave with a frequency of fsw = 5.6 GHz is observed when a pumping microwave with a frequency of fmw = 11.2 GHz is applied. The wave is found to be of the n = 1 width mode (n is the antinode number), and its mode changes to an edge-localized (or possibly n > 1) mode when the Oersted field (or current) varies. Joule heating effects are not observed in the pumping process. Thus, spin wave mode control by the built-in current would be a convenient and useful method to enhance the efficiency and compatibility in applications of spin-based electronics.
Subject(s)
Hepatectomy/methods , Laparoscopy/methods , Liver/surgery , Living Donors , Propensity Score , Tissue and Organ Harvesting/methods , Adult , Female , Humans , MaleABSTRACT
A new movable 3PM-γ coincidence system, based on 4πß(LS)-γ coincidence counting, for activity measurement of ß-γ emitters has been designed at the Korea Research Institute of Standards and Science (KRISS). The system incorporates 3 PM tubes on the plane and two detectors placed above and below the center of the plane. The 3 PM tubes for ß-counters in the plane are movable up to 100 mm from a liquid scintillation vial, thus enabling the variation of ß-detection efficiencies by a geometrical technique. A NaI(Tl) γ-counter was set above for the present work. The ß-event is determined by counting the logical sum of three double coincidences. All the necessary electronics, i.e., logical sum, adjusting the duration of dead-time of each counting channel and coincidence resolving times, and analyzing coincidence relation, were specially designed to be fabricated in an integrated circuit. Details of the detectors, the electronics, the overall movable 3PM-γ coincidence system are presented, as well as the results of investigations to assess its operating characteristics. Validation measurements have been performed with 60Co and 57Co sources. The highest ß-detection efficiency achieved with 60Co and 57Co was 97% and 95%, respectively. The activity concentration determined with a new system agreed with calibrated values within the uncertainty range. Further results from validation measurements and the corresponding uncertainty budgets are presented.
ABSTRACT
In an emulsion-counter hybrid experiment performed at J-PARC, a Ξ^{-} absorption event was observed which decayed into twin single-Λ hypernuclei. Kinematic calculations enabled a unique identification of the reaction process as Ξ^{-}+^{14}Nâ_{Λ}^{10}Be+_{Λ}^{5}He. For the binding energy of the Ξ^{-} hyperon in the Ξ^{-}-^{14}N system a value of 1.27±0.21 MeV was deduced. The energy level of Ξ^{-} is likely a nuclear 1p state which indicates a weak ΞN-ΛΛ coupling.