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Fluid intelligence (Gf) involves logical reasoning and novel problem‐solving abilities. Often, abstract reasoning tasks like Raven's progressive matrices are used to assess Gf. Prior work has shown an age‐related decline in fluid intelligence capabilities, and although many studies have sought to identify the underlying mechanisms, our understanding of the critical brain regions and dynamics remains largely incomplete. In this study, we utilized magnetoencephalography (MEG) to investigate 78 individuals, ages 20–65 years, as they completed an abstract reasoning task. MEG data was co‐registered with structural MRI data, transformed into the time–frequency domain, and the resulting neural oscillations were imaged using a beamformer. We found worsening behavioral performance with age, including prolonged reaction times and reduced accuracy. MEG analyses indicated robust oscillations in the theta, alpha/beta, and gamma range during the task. Whole brain correlation analyses with age revealed relationships in the theta and alpha/beta frequency bands, such that theta oscillations became stronger with increasing age in a right prefrontal region and alpha/beta oscillations became stronger with increasing age in parietal and right motor cortices. Follow‐up connectivity analyses revealed increasing parieto‐frontal connectivity with increasing age in the alpha/beta frequency range. Importantly, our findings are consistent with the parieto‐frontal integration theory of intelligence (P‐FIT). These results further suggest that as people age, there may be alterations in neural responses that are spectrally specific, such that older people exhibit stronger alpha/beta oscillations across the parieto‐frontal network during abstract reasoning tasks. [ABSTRACT FROM AUTHOR]

The influence of multistage heat treatments on the microstructure and mechanical properties of Ti-6Al-7Nb alloy used for functional structures was systematically studied. Cast Ti-6Al-7Nb alloy samples were subjected to hot forging, annealing, and multiple stages of heat treatments. The relationship between volume fraction of α-phase and the mechanical properties was investigated. Herein, multiple heat treatment steps were selected based on the dilatometric analysis, at the end of the beta transformation and the start of the beta transformation, followed by aging at low temperature, i.e., 500 °C. A higher volume fraction of α-phase leads to higher strength but lower ductility. The yield, ultimate tensile strengths, and ductility of the annealed alloy are 822 MPa, 1019 MPa, and 10%, respectively. The corresponding values for the alloy treated at 900 °C followed by WQ are 777 MPa, 932 MPa, and 16%, while the aged alloy has 879 MPa, 967 MPa, and 12%, respectively. A trade-off between strength and ductility was attained. Besides, the microstructural evolution of the studied conditions was also covered in depth. [ABSTRACT FROM AUTHOR]

• Hyperthermia is known to inhibit postirradiation DNA damage repair. • This could alter the α/β values in tumours. • α/β were estimated from 12 clinical trials of thermoradiotherapy vs radiotherapy. • α/β with thermoradiotherapy was computed as 2.25 Gy (95% CI: 1.8–2.7). • This should guide in optimizing thermoradiotherapy dose-fractionation schedules. Hyperthermia inhibits the repair of irradiation-induced DNA damage and thereby could alter the α/β values of tumours. This study estimates the clinical α/β HTRT values from clinical trials of thermoradiotherapy (HTRT) vs radiotherapy (RT) in recurrent breast (RcBC), head and neck (III/IV) (LAHNC) and cervix cancers (IIB-IVA) (LACC). Three recently published meta-analyses for HTRT vs RT in RcBC, LAHNC and LACC were evaluated for complete response (CR). Studies with specified RT dose (D), dose/fraction (d) and corresponding CRs were selected. Tumour biological effective dose (BED) for each study with RT (BED RT) was computed assuming an α/β RT of 10 Gy. As outcomes were favourable with HTRT, thermoradiobiological BED (BED HTRT) was calculated as a product of BED RT and %CR HTRT /%CR RT. The α/β HTRT was estimated as Dd/(BED HTRT – D). 12 trials with 864 patients were shortlisted – RcBC (3 studies, n = 259), LAHNC (5 studies, n = 338) and LACC (4 studies, n = 267). Overall risk difference of 0.28 favoured HTRT (p < 0.001). Mean BED RT and BED HTRT were 64.7 Gy (SD: ±15.5) and 109.5 Gy (SD: ±32.1) respectively and global α/β HTRT was 2.25 Gy (SD: ±0.79). Mean α/β HTRT for RcBC, LAHNC and LACC were 2.05 Gy, 1.74 Gy and 3.03 Gy respectively. On meta-regression, α/β HTRT was the sole predictor for the corresponding risk differences of the studies (coefficient = −0.096; p = 0.03). Thermoradiobiological effects on the repair of RT induced DNA damage results in reduction in α/β values of tumours. This should be considered to effectively optimize HTRT dose-fractionation schedules in the clinic. [ABSTRACT FROM AUTHOR]

At nuclear installations a large number of samples is used to control operational tasks and health physics parameters. A fast screening process can be applied to provide immediate indication on possible contamination, and liquid scintillation counting (LSC) is the preferred method. Many LSC systems, which do not perform pulse shape analysis, are still in use. A screening procedure for these systems is presented based on three windows analysis. It may greatly reduce work and time, compared to using a proportional counter system, besides providing more accurate results. [ABSTRACT FROM AUTHOR]

Brain oscillations are one of the core mechanisms underlying episodic memory. However, while some studies highlight the role of synchronized oscillatory activity, others highlight the role of desynchronized activity. We here describe a framework to resolve this conundrum and integrate these two opposing oscillatory behaviors. Specifically, we argue that the synchronization and desynchronization reflect a division of labor between a hippocampal and a neocortical system, respectively. We describe a novel oscillatory framework that integrates synchronization and desynchronization mechanisms to explain how the two systems interact in the service of episodic memory. [ABSTRACT FROM AUTHOR]

Raw and potable water sample sources, from the Umgeni Water catchment areas (rivers, dams, boreholes) in central KwaZulu-Natal (South Africa), were screened for Uranium concentration and alpha and beta radioactivity. Test methods used were gas flow proportional counting for alpha-beta radioactivity, and kinetic phosphorescence analysis (KPA), for Uranium. The uranium levels (median = 0.525 μg/L, range = <0.050–5.010) were well below the international World Health Organization (WHO) (2011) guideline for drinking-water quality (≤15 μg/L). The corresponding alpha and beta radioactivity was ≤0.5 Bq/L (median = 0.084, Interquartile Range (IR) = 0.038, range = 0.018–0.094), and ≤1.0 Bq/L (median = 0.114, IR = 0.096, range = 0.024–0.734), respectively, in compliance with the international WHO limits. For uranium radionuclide, the average dose level, at uranium level of ±0.525 μg/L, was 0.06 μSv/a, which complies with the WHO reference dose level for drinking water (<0.1 mSv/a). There was a distinct trend of cluster of relatively higher Uranium levels of some sources that were found to be associated with the geology/geography and groundwater sources. Overall, the radiological water quality classification, with respect to WHO, is “Blue” – ideal; additional physicochemical analyses indicated good water quality. The analytical test methods employed were found to be suitable for preliminary screening for potential radioactive “hot spots”. The observed Uranium levels, and the alpha/beta radioactivity, indicate contribution largely from Naturally Occurring Radioactive Material (NORM), with no significant health risk to humans, or to the environment. [ABSTRACT FROM AUTHOR]

Purpose: To estimate the α/β ratio for rectal cancer according to the outcome of three fractionation schedules of preoperative radiotherapy. Methods and Materials: Between 1996 and 2002, 168 patients with locally advanced rectal cancer were treated as follows: 53 patients received 25 Gy in 5 Gy per fraction, 45 received 30 Gy in 3.0 Gy per fraction, and 70 were treated with accelerated hyperfractionation (42 Gy, 1.5 Gy per fraction, given twice daily). No patients received concurrent chemotherapy. The clinical characteristics of the groups were comparable. Surgery was performed shortly after radiotherapy. Crude data on locoregional tumor control were fitted directly using a linear-quadratic model, and the actuarial data were analyzed using Cox model. Results: A linear-quadratic model provided an α estimate of 0.339 (SE 0.115) and β estimate of 0.067 (SE 0.027), which resulted in an α/β ratio of 5.06 Gy (95% confidence interval −0.1 to 10.3). In all three schemes the overall radiation treatment time was short, which limits the rationales for incorporating time effect into the model. If, however, time was incorporated the α/β ratio was 11.1 Gy and the dose increment required to compensate for repopulation was 0.15 Gy/day. The actuarial analysis provided similar α/β estimates. Conclusion: Although because of the retrospective character of the study, nonrandomized selection of fractionation schedule, and uncontrolled quality of surgery the present results can be regarded as hypothesis generating only, the control rates obtained in the pelvis are consistent with a moderately low α/β ratio for rectal cancer. [Copyright &y& Elsevier]

Abstract: There has been an intense debate over the past several years on the relevant α/β value that could be used to describe the fractionation response of prostate tumours. Previously it has been assumed that prostate tumours have high α/β values, similar to most other tumours and the early reacting normal tissues. However, the proliferation behaviour of the prostate tumours is more like that of the late reacting tissues, with slow doubling times and low α/β values. The analyses of clinical results carried out in the past few years have indeed suggested that the α/β value that characterises the fractionation response of the prostate is low, possibly even below the 3Gy commonly assumed for most late complications, and hence that hypofractionation of the radiation treatment might improve the therapeutic ratio (better control at the same or lower complication rate). However, hypofractionation might also increase the complication rates in the surrounding late responding tissues and if their α/β value is not larger that of prostate tumours it could even lead to a decrease in the therapeutic ratio. Therefore, the important question is whether the α/β value for the prostate is lower than the α/β values of the surrounding late responding tissues at risk. This paper reviews the clinical and experimental data regarding the radiobiological differential that might exist between prostate tumours and the late normal tissues around them. Several prospective hypofractionated trials that have been initiated recently in order to determine the α/β value or the range of values that describe the fractionation response of prostate tumours are also reviewed. In spite of several confounding factors that interfere with the derivation of a precise value, it seems that most data support a trend towards lower α/β values for prostate tumours than for rectum or bladder. [Copyright &y& Elsevier]

Background: Tumor regression parameters and time factor during external radiotherapy (EXTRT) are of paramount importance.Aims: To quantify the parameters of tumor regression and time factor during EXTRT in cancer cervix.Settings and Design: Patients, treated solely with radiotherapy and enrolled for other prospective studies having weekly tumor regressions recorded were considered.Materials and Methods: Seventy-seven patients received 50 Gy of EXTRT followed by intracavitary brachytherapy. Loco-regional regressions were assessed clinically and regression fraction (RF) was represented as RF=c + a 1D + a 2 D2 sub - a 3T, with c, D and T as constant, cumulative EXTRT dose and treatment time respectively.Statistical Analysis Used: Step wise linear regression was performed for RF. Scatter plots were fitted using linear-quadratic fit.Results: Coefficients of parameters D, D2 sub and T were computed for various dose intervals, namely 0--20 Gy, 0--30 Gy, 0--40 Gy and 0--50 Gy. At 0--20 Gy and 0--30 Gy, only the coefficient of D2 was significant (P 2 sub and T turned significant (P 2 sub and T showed significance, leading to an estimate of 26 Gy for a1/a2 and 0.96 Gy/day for a3/a1.Conclusions: As with alpha/beta and gamma/alpha of post-irradiation cell survival curves, a1/a2 and a3/a1 represents the cumulative effect of various radiobiological factors influencing clinical regression of tumor during the course of EXTRT. The dynamic changes in the coefficients of D, D2 sub and T, indicate their relative importance during various phases of EXTRT. [ABSTRACT FROM AUTHOR]

: PurposeRecently, low α/β values of 1.2 and 1.5 Gy for prostate tumors have been derived from clinical results of external beam radiotherapy and of permanent implants of 125I and 103Pd. In the analyses the contributions of tumor repopulation, and edema as a result of inserting radioactive seeds in the prostate, have been ignored. In this paper we reanalyzed the clinical data and introduced the contribution of repopulation and edema.: Methods and materialsThe linear quadratic–biologically effective dose model was used for reanalysis. In this model, the influence of repopulation and edema has been taken into account. The biologically effective dose was calculated as a function of α/β for 2 brachytherapy regimens with 125I and 103Pd and 2 fractionated treatments, and for different half-times for repair of sublethal damage for the brachytherapy regimens.: ResultsWe have found a plausible α/β value of 3.1 to 3.9 Gy, an α value of 0.1 to 0.15 Gy−1, and a half-time of repair of about 0.5 h.: ConclusionsIt seems now that the α/β value is low, 3.1–3.9 Gy, but not as low as the 1.2 and 1.5 Gy reported earlier. [Copyright &y& Elsevier]