Is the radon risk overestimated? Neglected doses in the estimation of the risk of lung cancer in uranium underground miners

Only the exposure to inhaled radon decay products is usually taken into account in the determination of the risk of radiogenic lung cancer in uranium miners. However, the elevated lung cancer risk in uranium miners is due to the total dose of radiation received by that organ, not to the dose from inhaled radon-222 decay products (222Rn D.P.) alone. Lung doses from sources other than 222Rn D.P. may reach 25% to 75% of total effective dose, absorbed dose or equivalent lung dose, are correlated to 222Rn D.P. doses and are quite variable between facilities. Therefore, to neglect these doses leads to a systematic overestimation of the risk of lung cancer per unit 222Rn D.P. exposure, both through dose underestimation and dose misclassification. Correction for neglected doses and dose misclassification would pull the risk per unit radon exposure downward by a factor of at least two or three and bring the overall dose-effect relationship towards the no-effect null hypothesis, thereby increasing the likelihood of thresholds for lung cancer risk at indoor and today's uranium mine exposures.     

Does mean lung dose calculated after inhalation of alpha emitters actually reflect the risk of induction of malignant lung tumours?

A comparison of incidence of lung tumours in rats after inhalation exposure to aerosols containing alpha emitters which have different physico-chemical properties has been performed. Aerosols of radon and progeny, uranium ore dust, NpO2, PuO2 or Cm2O3 were considered for intercomparison with similar or different particle sizes. Dose-effect relationships for the frequency of malignant lung tumours appear linear up to a few Gy and then become infralinear at higher doses delivered to the lungs. The initial slope of the curves reflects the risk of induction of a lung tumour. The highest slopes of incidence were observed for radon and uranium ore dust (about 70 and 20% Gy(-1) respectively) for which the most homogeneous alpha dose distribution to the lungs is expected. In a general trend, increasing the alpha-activity of deposited particles (higher specific activity of constituent radioisotopes or larger particle size) decreases the risk. The comparison of the reported data shows that the risk per Gy at 'low doses' could vary over more than one order of magnitude depending on the physico-chemical properties of the aerosols.     

Are radon gas measurements adequate for epidemiological studies and case control studies of radon-induced lung cancer?

The lung dose derived from radon is not attributed to the radon gas itself, but instead to its short-lived progeny. However, in many epidemiological studies as well as in case control studies of the radon risk, the excess number of cancers are related to the radon gas exposure, and not to the radon progeny exposure. A justification for such an approach has resorted to the assumption that there is self-compensation between the radiation doses from the unattached and attached fractions. In the present study, we used the Jacobi model to calculate the radon progeny concentrations in a room by varying the attachment rate and then calculated the resulting lung dose. It was found that self-compensation was not fully realised, and the effective dose can vary by a factor up to approximately 2 for the same radon gas concentration. In conclusion, the radon gas concentration alone does not provide adequate information on the effective dose.     

Does monetary support increase citation impact of scholarly papers?

Scientometrics - One of the main indicators of scientific development of a given country is the number of papers published in high impact scholarly journals. Many countries introduced...     

Does the institutional diversity of editorial boards increase journal quality? The case economics field

Scientometrics - In academic communication, editors exert a significant influence on a journal’s mission and content. We examined how the composition of editorial board members, in particular...     

Dosimetric and epidemiological approaches to assessing radon doses--can the differences be reconciled?

A significant problem in internal radiation dosimetry is the discrepancy between the radiation dose from exposure to radon inferred from epidemiological studies and the higher dose calculated using the Human Respiratory Tract Model (HRTM) adopted by the International Commission on Radiological Protection (ICRP). The difference is a factor of about 3. The agreement between these two assessments by radically different approaches is surprisingly good. Nevertheless, there has been concern to understand fully the reasons for this discrepancy and to attempt to reconcile the two approaches. This is of importance because radon contributes about half of the total effective dose from natural background radiation. Furthermore, the HRTM was developed with application to radon exposure in mind, yet at present it is not used for risk assessment purposes although ICRP does suggest that it is useful for comparative dosimetry.     

Does the transition to parenthood influence driving?

Most parents remember the first time they drove with a newborn child in the car. Feeling the need to protect the infant, they avoided sharp turns and drove more slowly and carefully than normal. But how long do these behaviors persist? Do parents ultimately revert to their previous driving patterns, or does some of the early protectiveness and caution continue to characterize their driving as their infant grows into a toddler and preschooler? In an attempt to answer these questions, two studies were conducted on parents of young children: a qualitative study consisting of personal interviews (16 parents); and a quantitative study in the form of a national telephone survey (165 parents). The results show that the most dominant reported effect of the transition to parenthood on driving is increased apprehension of traffic crashes and a stronger sense of responsibility. However, these changes were found to influence the reported actual driving behavior of only a portion of the parents. Possible explanations of the findings are discussed.     

Can Twitter increase the visibility of Chinese publications?

Scientometrics - The purpose of this study is to investigate whether diffusion through social media can help to improve the international visibility of Chinese papers and thus increase their...     

Does hemodiafiltration improve the removal of homocysteine?

High prevalence of hyperhomocysteinemia is common in hemodialysis (HD) patients and could contribute to worsen the cardiovascular risk. Beyond vitamin B status, dialysis modality itself could influence homocysteine (Hcy) levels. The objective was compare the reduction rate (RR) of Hcy and cysteine in stable dialyzed patients treated by standard HD or hemodiafiltration (HDF). Seventy‐five patients undergoing stable dialysis through standard high‐flux HD (n = 35) or HDF (n = 40) were included. Biological parameters were determined before and after a midweek dialysis session. Urea percent reduction per session and Kt/V index (K, body urea clearance, T, time of dialysis, and V, urea distribution volume), defined as a marker of dialysis efficacy, were similar between HD and HDF groups. By contrast, higher RR of beta2 microglobulin (β2m) was observed in HDF compared with HD (78.6 vs. 72.0%, respectively; P < 0.001). Likewise, higher RR of Hcy was obtained with HDF compared to HD (46.0 vs. 41.5%, respectively; P < 0.05), whereas the RR of cysteine was similar in both groups. Interestingly, a positive correlation between Hcy RR and urea Kt/V index was observed (r = 0.29, P < 0.05) and between Hcy RR and β2m RR (r = 0.45, P < 0.001). Time‐averaged concentration (TAC) of Hcy was lower with HDF compared with HD (17.8 vs. 19.1 μmol/L, respectively), although not significant. There was no difference in median Hcy according to dialysis modality for neither pre‐ nor postdialysis levels. Significant higher removal of Hcy was observed with HDF compared with standard HD, although urea Kt/V index was similar. Enhanced removal of middle molecules, such as β2m, could be involved in Hcy RR improvement with HDF.     

Does the multi-authorship trend influence the quality of an article?

In the last few decades, multi-authored articles have increased in different disciplines with increasing instances of authorship abuse although multi-authorship is not always due to undeserving authorship (McDonald et al. in Mayo Clin Proc 85(10):920–927, 2010). It may be necessitated by interdisciplinary research, the evolution of a discipline, or the intention of quality improvement. This article studies the relationship between the authorship and the quality of articles (publications in better impact factor journals or core journals) in the field of Oceanography. The result shows ~75 % increase in the number of authors per article from 1990 to 2009 in the discipline. The increase in authorship correlates not only with the percentage of articles in core journals but also with the mean impact factor (IF) of journals (where the articles were published). The ANOVA study shows that though multi-authorship has no influence on the preference to publish in core journals during the 1990s or 2000s, it does have a significant influence on the preference to publish in high IF journals in both the decades. So these findings establish that in the field of Oceanography, the increase in collaboration would have resulted in more publications in core journals (without any influence of authorship increase) and in better impact factor journals (due to the influence of authorship increase).     

Does gender moderate the relationship between driver aggression and its risk factors?

Aim

The current study assessed gender as a potential moderator of the relationship between self-reported driver aggression and various demographic variables, general and driving-related risk factors.

Methods

Using data from a general-population telephone survey conducted from July 2002 through June 2005, two approaches to binary logistic regression were adopted. Based on the full dataset (n = 6259), the initial analysis was a hierarchical-entry regression examining self-reported driver aggression in the last 12 months. All demographic variables (i.e., gender, age, income, education, marital status), general risk factors (i.e., psychological distress, binge drinking, cannabis use), and driving-related risk factors (i.e., driving exposure, stressful driving, exposure to busy roads, driving after drinking, driving after cannabis use) were entered in the first block, and all two-way interactions with gender were entered stepwise in the second block. The subsequent analysis involved dividing the sample by gender and conducting logistic regressions with main effects only for males (n = 2921) and females (n = 3338) separately.

Results

Although the prevalence of driver aggression in the current sample was slightly higher among males (38.5%) than females (32.9%), the difference was small, and gender did not enter as a significant predictor of driver aggression in the overall logistic regression. In that analysis, difficulty with social functioning and being older were associated with a reduced risk of driver aggression. Marital status and education were unrelated to aggression, and all other variables were associated with an increased risk of aggression. Gender was found to moderate the relationships between driver aggression and only three variables: income, psychological distress, and driving exposure. Separate analyses on the male and female sub-samples also found differences in the predictive value of income and driving exposure; however, the difference for psychological distress could not be detected using this separate regression approach. The secondary analysis also identified slight differences in the predictive value of four of the risk factors, where the odds ratios for both males and females were in the same direction but only one of the two was statistically significant.

Conclusions

The results demonstrate the importance of conducting the gender analysis using both regression approaches. With few exceptions, factors that were predictive of driver aggression were generally the same for both male and female drivers.     

What can cities do to increase resilience?

This paper examines climate change mitigation and adaptation from an insurance industry perspective, with particular reference to London and the USA. It illustrates how British insurers are increasingly shaping public policy and using new technology to manage the risks from climate change impacts and makes a plea for society to make more use of insurance expertise in future decision making. In particular, more dialogue is needed between architects, planners and insurers to adapt our buildings and cities for climate change impacts. The paper is an abbreviated and updated version of the paper presented by the author in Houston, Texas, in 2005.     

Does the higher citation of collaborative research differ from region to region? A case study of Economics

Many studies have found that collaborative research is, in general, more highly cited than non-collaborative research. This paper describes an investigation into the extent to which the association between high citation and collaboration for Economics articles published in 2000 varies from region to region and depends on the choice of indicator of citation level. Using data from the Social Science Citation Index (SSCI) for 18 countries, 17 American states and four indicators of citation level the citation levels of the collaborative articles are compared with the citation levels of the non-collaborative articles. The main findings are that: (a) for every country and every indicator the mean citation level of the collaborative articles was at least as high as that for the non-collaborative articles, but for five US states and for at least one other indicator the citation level of collaborative articles was lower than that of non-collaborative articles, and (b) the extent to which collaborative articles were more highly cited varied considerably from country to country, from state to state, and from indicator to indicator. This indicates the importance of using multiple indicators when investigating citation advantage since the choice of indicator can change the results.     

Modifications to bicarbonate conductivity: A way to increase phosphate removal during hemodialysis? Proof of concept

Introduction Hyperphosphatemia and cardiovascular mortality are associated particularly with end‐stage renal disease. Available therapeutic strategies (i.e., diet restriction, calcium [or not]‐based phosphate binders, calcimimetics) are associated with extrarenal blood purification. Compartmentalization of phosphate limits its depuration during hemodialysis. Several studies suggest that plasmatic pH is involved in the mobilization of phosphate from intracellular to extracellular compartments. Consequently, the efficiency of modified bicarbonate conductivity to purify blood phosphate was tested. Methods Ten hemodialysis patients with chronic hyperphosphatemia (>2.1 mmol/L) were included in the two three–sessions‐per week periods. Bicarbonate concentration was fixed at 40 mmol/L and 30 mmol/L in the first and second periods, respectively. Phosphate depuration was evaluated by phosphate mobilization clearance (K_M). Findings Although bicarbonatemia was lower during the second period (21.0 ± 2.7 vs. 24.4 ± 3.1 mmol/L, P < 0.01), no difference was observed in phosphatemia (2.4 ± 0.5 vs. 2.3 ± 0.4 mmol/L, P = NS). The in‐session variation of phosphate was lower (?1.45 ± 0.42 vs. ?1.58 ± 0.44 mmol/L, P < 0.05) and K_M was higher during the second period (82.94 ± 38.00 vs. 69.74 ± 24.48 mL/min, P < 0.05). Discussion The decrease of in‐session phosphate and the increase in K_M reflect phosphate refilling during hemodialysis. Thus, modulation of serum bicarbonate may play a role in controlling the phosphate pool. Even though correcting metabolic acidosis during hemodialysis remains important, alkaline excess can impair phosphate mobilization clearance. Clinical trials are needed to test the efficiency and relevance of a strategy where bicarbonatemia is corrected less at the beginning of sessions.     

Reduction of post-shift traffic injuries among gasoline station workers: Are they related to the reduction of occupational gasoline vapor exposure?

AIMS: Solvents exposure is known to impair psychomotor performances. With gasoline vapor recovery devices (GVRD) installed, this study should observe a decrease of traffic injuries after shift among gasoline workers. METHODS: The occupational injury registry data of 1991-2000 in a petrochemical company containing 20,000 workers were analyzed. Cumulative injury rate (CIR) was calculated to estimate lifetime risk. The potential workday loss (PWDL) and the potential salary loss (PSL), which summed up the expected workdays and salary loss assuming a uniform retirement age of 65, were calculated for traffic injuries. Workers of gasoline sales were compared with those without gasoline exposure for commuting traffic injuries. The rate ratio (RR) was calculated based on a person-time data. RESULTS: The CIR dropped 3.14 times during 1997-2000 for commuting accidents on the way back home compared with that during 1991-1992, and the PWDL and PSL dropped 25.2 and 21.5 times, respectively, which corresponded with the time of installments of GVRD. The RRs of commuting accidents on the way back home in the exposed group significantly decreased from 2.15 to 0.53. CONCLUSIONS: The decrease of commuting injuries on journey back home for gasoline workers were probably related to the effective reduction of solvent exposure.     

What happened in Finland to increase home hemodialysis?

Finland is geographically a rather large country with a relatively sparse population (5.3 million). Home hemodialysis (HHD) was started in Helsinki 40 years ago and in the early years it was only used in selected patients. However, by the late 1980s HHD almost disappeared owing to the advent of CAPD and new HD centers. Towards the end of the 1990s, it became evident that PD had limitations and new ways had to be found to individualize HD, improve the outcome, increase capacity, and limit the growth of costs of HD. After careful planning, HHD was reinstituted at the Helsinki University Hospital in 1998 and since then the program has grown steadily. By December 31, 2007, altogether 163 patients had started at home. This has required changes in the predialysis program where the "home first" policy was adopted. Other important features include close cooperation with other nephrological centers as well as centralized HHD training that also supports more remote hospitals. Since then this therapy has been started in several other academic and in some smaller hospitals, and at the end of last year about 4% of all Finnish dialysis patients (n=1.600) were on HHD (prevalence 11.8/million). In the Helsinki metropolitan area this treatment is the most economical modality (estimated annual global costs euro37.000), comparable to self-care satellite HD and CAPD. A successful HHD program requires a well-organized predialysis program, a highly motivated multidisciplinary team, and well-developed training networks.     

Does the extracorporeal blood flow affect survival of the arteriovenous vascular access?

Hemodiafiltration with high‐convective volumes is associated with improved patient survival, whereby practical realization is contingent on high extracorporeal blood flow (Qb) and dialysis treatment time. However, Qb is restricted by vascular access (VA) quality and/or concerns that high Qb could damage the VA. Taking VA quality into consideration, one can investigate the relationship between Qb and VA survival. We analyzed data from 1039 patients treated by hemodiafiltration over a 21‐month period where access blood flow (Qa) measurements were also available at baseline. VA failure was defined as a surgical intervention resulting in the generation of a new VA. Qa was included as a stratification variable within a Cox regression model. A second Cox proportional hazard model with a penalized spline was used to describe the association between Qb and VA survival. Compared with Qb in the 350–357 mL/min range, a significantly higher hazard ratio (HR) for VA failure was detected for fistula only, and then only for Qb < 312 mL/min (HR: 2.361, 95% confidence interval [CI]: 1.251–4.453), Qb = 387–397 mL/min (HR: 1.920, 95% CI: 1.007–3.660) and Qb >414 mL/min (HR: 2.207, 95% CI: 1.101–4.424). Age, gender, diabetes, VA vintage, position of the VA, and arterial pressure were not significantly associated with outcome. The form of the penalized spline confirmed higher risk for VA failure for the lowest and the highest values of Qb. Taking Qa into consideration, no association was found between VA failure and Qb up to flows as high as approximately 390 mL/min.     

Does the Phenomenological Approach Contradict the Quantum Theory of Exciton-Polariton Spatial Dispersion?

This paper clarifies the controversial issue over 40 years between the quantum approach by Pekar and the phenomenological approach by Ginzburg about the exciton-polariton spatial dispersion theory. For an isotropic nongyrotropic medium, the analytical explicit function of the impermeability tensor \(\eta _{ij} (\omega ,\mathop k\limits^ \to )\) (the inverse of the permittivity tensor) is obtained from the anisotropic undamped-wave harmonic oscillator model. After expanding \(\eta _{ij} (\omega ,\mathop k\limits^ \to )\) with respect to small parameters within it rather than to wavevector \(\mathop k\limits^ \to\), the approximate refractive indices can be determined from the eigenvalue equation. By this treatment, the phenomenological approach is proved to be the approximation of the quantum approach near the resonance frequency. The condition for the approximation is discussed.