The main goal of the present study was estimation of an internal contamination of
131
I among family members of patients treated with radioactive iodine. Thyroid activity measurements of
131
I in ...examined volunteers were performed using a whole-body spectrometer at the institute of nuclear physics, Polish academy of sciences. During this research, 20 relatives of patients treated with
131
I were examined: eight women and 12 men with an age in the range from 3 to 72 years. In the case of nine individuals, the activity of
131
I in the thyroid was below the detection limit, but among the remaining 11 individuals, the activity varied from (9 ± 3) Bq up to (1140 ± 295) Bq. Subsequently, based on the measurements of thyroid
131
I activities, the corresponding doses were assessed. The highest estimated effective dose reached 218 μSv, while the thyroid equivalent dose was 2.4 mSv. In addition, the experimental data obtained were statistically analysed together with the results of surveys of the individuals participating in the study by means of correspondence analysis and nonparametric tests: Mann–Whitney, gamma,
χ
2
and Yule Phi coefficient. These analyses revealed relationships between
131
I activities in the thyroids of the examined individuals and their housing conditions as well as consumption of meals prepared by the patients.
Abstract
Experiments searching for the neutrinoless double beta decay in
$$^{76}$$
76
Ge are currently achieving the lowest background level and, in connection with the excellent energy resolution of ...germanium detectors, they exhibit the best discovery potential for the decay. Expansion to a ton scale of the active target mass is presently considered – in this case on-site production of the detectors may be an option. In this paper we describe the fabrication and characterization procedures of a prototype detector with a small p
+
contact, which enhances the abilities of the pulse shape discrimination – one of the most important tools for background reduction. Simulations of the shapes of pulses from the detector were carried out and tuned, taking the advantage of the fact that all the parameters of the Ge crystal, cryostat and of the spectroscopic chain were known. As a result, the pulse shape analyses performed on the simulated and measured data agree very well. The worked out method allows to optimize geometry and crystal parameters in terms of pulse shape analysis efficiency, before the actual production of the detectors.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Experiments searching for the neutrinoless double beta decay in
76
Ge are currently achieving the lowest background level and, in connection with the excellent energy resolution of germanium ...detectors, they exhibit the best discovery potential for the decay. Expansion to a ton scale of the active target mass is presently considered – in this case on-site production of the detectors may be an option. In this paper we describe the fabrication and characterization procedures of a prototype detector with a small p
+
contact, which enhances the abilities of the pulse shape discrimination – one of the most important tools for background reduction. Simulations of the shapes of pulses from the detector were carried out and tuned, taking the advantage of the fact that all the parameters of the Ge crystal, cryostat and of the spectroscopic chain were known. As a result, the pulse shape analyses performed on the simulated and measured data agree very well. The worked out method allows to optimize geometry and crystal parameters in terms of pulse shape analysis efficiency, before the actual production of the detectors.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This paper contains a Monte Carlo evaluation of estimators used to control for endogeneity of dummy explanatory variables in continuous outcome regression models. When the true model has bivariate ...normal disturbances, estimators using discrete factor approximations compare favorably to efficient estimators in terms of precision and bias; these approximation estimators dominate all the other estimators examined when the disturbances are non-normal. The experiments also indicate that one should liberally add points of support to the discrete factor distribution. The paper concludes with an application of the discrete factor approximation to the estimation of the impact of marriage on wages.
This paper presents results of measurements of
99m
Tc activity concentration in air and nuclear medical personnel blood during ventilation–perfusion SPECT lung scans.
99m
Tc activity measurements ...were conducted at the Nuclear Medicine Department, John Paul II Hospital, Krakow. Technicians and nurses who perform examinations were equipped with personal aspirators enabling air sampling to determine the radiation exposure at their workplaces. Measurements allowed to evaluate the concentration of
99m
Tc in 14 air samples and it ranged from 7800 ± 600 to 10,000 ± 1000 Bq m
−3
for air samples collected by technicians and from 390 ± 30 to 600 ± 40 Bq m
−3
for air samples collected by nurses. In addition
99m
Tc concentrations in blood of medical personnel were determined in 24 samples. For technicians the maximum
99m
Tc blood concentration levels reached 920 ± 70 Bq L
−1
and 1300 ± 100 Bq L
−1
. In the case of nurses, the maximum estimated activity concentrations were about ten times lower, namely 71 ± 7 Bq L
−1
and 39 ± 3 Bq L
−1
. Although the intakes appear to be relatively high, the resulting annual effective doses are about 34 µSv for technicians and only 2 µSv for nurses.
This paper presents results of
131
I thyroid activity measurements in 30 members of the nuclear medicine personnel of the Department of Endocrinology and Nuclear Medicine Holy Cross Cancer Centre in ...Kielce, Poland. A whole-body spectrometer equipped with two semiconductor gamma radiation detectors served as the basic research instrument. In ten out of 30 examined staff members, the determined
131
I activity was found to be above the detection limit (DL = 5 Bq of
131
I in the thyroid). The measured activities ranged from (5 ± 2) Bq to (217 ± 56) Bq. The highest activities in thyroids were detected for technical and cleaning personnel, whereas the lowest values were recorded for medical doctors. Having measured the activities, an attempt has been made to estimate the corresponding annual effective doses, which were found to range from 0.02 to 0.8 mSv. The highest annual equivalent doses have been found for thyroid, ranging from 0.4 to 15.4 mSv, detected for a cleaner and a technician, respectively. The maximum estimated effective dose corresponds to 32% of the annual background dose in Poland, and to circa 4% of the annual limit for the effective dose due to occupational exposure of 20 mSv per year, which is in compliance with the value recommended by the International Commission on Radiological Protection.
Abstract
Introduction:
Napping is a highly prevalent but poorly understood form of sleep in older adults. Research suggests that naps are associated with older age, being male, and multiple ...comorbidities such as pain and depression but studies typically do not distinguish between planned and spontaneous naps. Additionally, little attention has been paid to nap duration. This study describes napping in older adults by sociodemographic and clinical characteristics, with particular attention paid to naps that are unplanned or >60 minutes.
Methods:
Retrospective cohort of Medicare beneficiaries ≥65 enrolled in the fourth year of National Health and Aging Trends Study (NHATS) who reported napping (n=1,016). Survey weighting was used for all analyses and to determine population estimates. Logistic regressions were used to examine the relationships between sociodemographic and clinical characteristics and napping behaviors.
Results:
Older adults who reported regularly napping, 58.7% reported that some or all naps were unplanned and that 18.5% regularly take naps > hour. Older age, non-white race, non-married status, poorer self-reported health, and shorter nighttime sleep duration were significantly associated with unplanned napping. For example, individuals 75–84 years of age had 2.1 times higher odds of unplanned naps compared to those aged 65–74. Male sex, poorer self-reported health, and a greater number of chronic conditions were associated with higher odds of naps > hour. Those with the worst self-reported health were 2.76 times more likely to take long naps than those reporting the best health. Neither pain nor depression were significantly associated with either unplanned or long naps.
Conclusion:
This study indicates that ~4.3 million older adults in the U.S. regularly fall asleep during the day without meaning to, and that 1.37 million older adults routinely take naps lasting longer than an hour. Furthermore, this research indicates different constellations of risk factors for unplanned napping and long duration napping. Additional research examining the impact of unplanned and long-duration napping is warranted.
Support (If Any):
NCMRR K01HD076183 (DJF) and AHRQ K01HS022907 (NEL)
Spinal metastases invariably affect the majority of patients with cancer. Many will develop symptoms related to pain and disability from epidural spinal cord compression as well as pathologic ...fracture of the vertebrae. With the emergence of targeted systemic therapies and a better understanding of cancer biology, patients are living longer with bony metastases. This poses particular challenges, as palliation of pain and maintenance of local tumor control are paramount to quality of life and overall functional independence for these patients. Stereotactic radiosurgery (SRS) has emerged as a potent primary standalone and adjuvant treatment option for spinal metastases. To date, the primary indications for SRS include 1) upfront standalone treatment for painful bony metastases in the oligometastatic patient, 2) standalone or post-operative treatment following progression or recurrence of local disease despite previous conventional external beam radiation therapy (cEBRT), and 3) following surgery during which epidural disease is decompressed and the spine stabilized when indicated. SRS has demonstrated a significant advantage over cEBRT for tumors traditionally regarded as relatively radioresistant such as sarcoma, melanoma, renal cell carcinoma, non-small cell lung cancer and colon carcinoma.9 The radiobiological advantage of increased tumoricidal dose delivery and spinal cord dose sparing in SRS have made this a powerful treatment alternative to cEBRT particularly within the context of re-irradiation. Given the limitations of spinal cord dose constraints, surgery is still the first-line therapy in patients with high-grade epidural spinal cord compression (ESCC). Epidural compression can be treated with SRS, however this risks radiation-induced myelopathy and challenges the safety of effective dose delivery at the dural margin.11 With increasing dose, radiation-induced vertebral fracture is the most serious and prevalent side effect of SRS.53 An overview of SRS, including the most common indications, complications, and outcomes for spinal metastases are presented here.
A ground-source heat pump (GSHP) system designed to cooperate with a low temperature heating system and hot water production was installed in a new passive house nearby the city of Poznan (Poland). ...The paper describes an integration of the GSHP system with a heat exchanger on the supply airflow in order to recover the waste heat from outside (fresh) ventilation air and store it in the ground during summer, as well as to heat the supply air in winter what prevents the recuperator from freezing. Analytical calculations to evaluate the energy, economy and environmental benefits of supplying the low heat reservoir with heat from fresh air were made. Chilled supply air compensates the heat gains from building and is exhausted, simultaneously overcoming a part of the cooling loads by using mechanical ventilation system. Heat taken in the heat exchanger by the glycol mixture is used in the evaporator of the heat pump, which produces hot water with increased energy efficiency - increased coefficient of performance (COP). After that glycol mixture is supplied to the ground. In the case of stagnation of the heat pump, glycol mixture exiting the heat exchanger is directed to the ground, where part of the delivered waste heat is stored. The results of calculation experiment indicated that heat recovered from the supply ventilation air during summer is increasing the Seasonal Performance Factor (SPF) of the heating system in winter, consequently significant energy savings can be achieved, what is a part of the idea of the Sustainable Development. Based on the simulations it has also been demonstrated that the proposed technical solution has a high application potential for micro and macro scale installations using GSHP.
The rapid change in diets, physical activity and body composition in low income countries has led to the coexistence of large pockets of undernutrition and overnutrition. Public health strategies for ...addressing this situation may be necessary, and price policy options are examined for China. Longitudinal dietary data collected in China in 1989-1993 on a sample of 5625 adults aged 20-45 y were examined. Three-day averages of food group consumption and nutrient intake were used in longitudinal statistical models to examine separately the effects of food prices on the decision to consume each food group and then the amount consumed. The effects of changes in six food prices on the consumption of each of six food groups, not just the food group whose price had changed, and on three macronutrients were estimated. The effects show large and significant price effects. If the joint effects of the nutrition transition are to be considered, then there are clear tradeoffs among which foods to tax and which to subsidize. Most important is the effect of prices in reducing fat intake of the rich but not adversely affecting protein intake for the poor. Increases in the prices of pork, eggs and edible oils are predicted to lower fat intake. Only increases in pork prices led to reduced protein intakes. This raises questions about earlier policy changes being implemented in China and provides insight into an important and controversial area for public health policy.
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