Factors controlling the groundwater transport of U, Th, Ra, and Rn

A model for the groundwater transport of naturally occurring U, Th, Ra, and Rn nuclides in the ^(238)U and ^(232)Th decay series is discussed. The model developed here takes into account transport by advection and the physico-chemical processes of weathering, decay, α-recoil, and sorption at the water-rock interface. It describes the evolution along a flowline of the activities of the ^(238)U and ^(232)Th decay series nuclides in groundwater. Simple sets of relationships governing the activities of the various species in solution are derived, and these can be used both to calculate effective retardation factors and to interpret groundwater data. For the activities of each nuclide, a general solution to the transport equation has been obtained, which shows that the activities reach a constant value after a distance ϰ_i, characteristic of each nuclide. Where ϰ_i is much longer than the aquifer length, (for ^(238)U, ^(234)U, and ^(232)Th), the activities grow linearly with distance. Where ϰ_i is short compared to the aquifer length, (for ^(234)Th, ^(230)Th, ^(228)Th, ^(228)Ra, and ^(224)Ra), the activities rapidly reach a constant or quasi-constant activity value. For ^(226)Ra and ^(222)Rn, the limiting activity is reached after 1 km. High δ ^(234)U values (proportional to the ratio ^(ɛ234)Th/^(W238)U) can be obtained through high recoil fraction and/or low weathering rates. The activity ratios ^(230)Th/^(232)Th, ^(228)Ra/^(226)Ra and ^(224)Ra/^(226)Ra have been considered in the cases where either weathering or recoil is the predominant process of input from the mineral grain. Typical values for weathering rates and recoil fractions for a sandy aquifer indicate that recoil is the dominant process for Th isotopic ratios in the water. Measured data for Ra isotope activity ratios indicate that recoil is the process generally controlling the Ra isotopic composition in water. Higher isotopic ratios can be explained by different desorption kinetics of Ra. However, the model does not provide an explanation for ^(228)Ra/^(226)Ra and ^(224)Ra/^(226)Ra activity ratios less than unity. From the model, the highest ^(222)Rn emanation equals 2_ɛ. This is in agreement with the hypothesis that ^(222)Rn activity can be used as a first approximation for input by recoil (Krishnaswamiet al 1982). However, high ^(222)Rn emanation cannot be explained by production from the surface layer as formulated in the model. Other possibilities involve models including surface precipitation, where the surface layer is not in steady-state

The third KV62 radar scan: Searching for hidden chambers adjacent to Tutankhamun's tomb

The existence of hidden chambers and corridors adjacent to Tutankhamun’s tomb (code name KV62) hasbeen long debated. In 2015 it was suggested that these chambers may host the as yet undiscovered burialof Nefertiti. In order to test this hypothesis, two Ground Penetrating Radar (GPR) surveys, conductedin 2015 and 2016 from inside KV62, were carried out, but gave contradictory results. To solve theseuncertainties and obtain a more confident and conclusive response, a third GPR survey was conductedby our team in February 2018. The results of this third radar scan are reported in this article. Three GPRsystems with multiple frequency bands (from 150 MHz to 3000 MHz) and very dense spatial samplingwere adopted. After careful data processing, no evidence of marked discontinuities due to the passagefrom natural rock to artificial blocking walls were found in the radargrams. It is therefore concluded thatthere are no hidden chambers immediately adjacent to the Tomb of Tutankhamun

Polyphenol Extract from "Greco" Grape Canes: Characterization, Antioxidant Capacity, and Antitumor Effects on Cal-33 and JHU-SCC-011 Head and Neck Squamous Cell Carcinoma

In the current study, we determined the antioxidant properties of "Greco" grape cane extracts, a typical cultivar of southern Italy. We also explored the anticancer activity of the polyphenol-rich fraction of the extract on head and neck squamous carcinoma cells (HNSCC) and investigated the underlying mechanism. Aqueous extracts were prepared at different pHs and extraction times and the total phenolic and reducing sugar contents were estimated. Radical Scavenging Activity (RSA), Ferric Reducing Antioxidant Power (FRAP), and Total Antioxidant Capacity (TAC) of the extracts were measured. A polyphenol-rich fraction, accounting for 6.7% by weight and characterized mainly by procyanidins and stilbenoids, was prepared from the extract obtained at pH 7 for 60 min. We demonstrated that the extract exerted a cytotoxic effect on HNSCC cell lines by inducing cell cycle arrest via cyclin downregulation and p21 upregulation, and by triggering apoptosis through caspase cascade activation, PARP-1 cleavage, and an increase in the Bax/Bcl-2 ratio. We furnished evidence that the polyphenol-rich fraction played the major role in the anticancer activity of the extract. These outcomes highlighted grape canes from the "Greco" cultivar as a valuable source of polyphenols that may represent good candidates for the design of innovative adjuvant therapies in the treatment of HNSCC

Experimental sexual selection reveals rapid evolutionary divergence in sex-specific transcriptomes and their interactions following mating

Work was supported by the Natural Environment Research Council (NE/I014632/1 to M.G.R., A.R.C., and R.R.S), the Natural Environment Research Council Biomolecular Analysis Facility (NBAF654 to M.G.R), and the Swedish Research Council (Vetenskapsrådet; 2018-04598 to R.R.S).Postcopulatory interactions between the sexes in internally fertilizing species elicits both sexual conflict and sexual selection. Macroevolutionary and comparative studies have linked these processes to rapid transcriptomic evolution in sex-specific tissues and substantial transcriptomic postmating responses in females, patterns of which are altered when mating between reproductively isolated species. Here we test multiple predictions arising from sexual selection and conflict theory about the evolution of sex-specific and tissue-specific gene expression and the postmating response at the microevolutionary level. Following over 150 generations of experimental evolution under either reduced (enforced monogamy) or elevated (polyandry) sexual selection in Drosophila pseudoobscura, we found a substantial effect of sexual selection treatment on transcriptomic divergence in virgin male and female reproductive tissues (testes, male accessory glands, the female reproductive tract and ovaries). Sexual selection treatment also had a dominant effect on the postmating response, particularly in the female reproductive tract ? the main arena for sexual conflict - compared to ovaries. This effect was asymmetric with monandry females typically showing more postmating responses than polyandry females, with enriched gene functions varying across treatments. The evolutionary history of the male partner had a larger effect on the postmating response of monandry females, but females from both sexual selection treatments showed unique patterns of gene expression and gene function when mating with males from the alternate treatment. Our microevolutionary results mostly confirm comparative macroevolutionary predictions on the role of sexual selection on transcriptomic divergence and altered gene regulation arising from divergent coevolutionary trajectories between sexual selection treatments.Publisher PDFPeer reviewe

The neglected liaison: Targeting cancer cell metabolic reprogramming modifies the composition of non‐malignant populations of the tumor microenvironment

Metabolic reprogramming is a well‐known hallmark of cancer, whereby the development of drugs that target cancer cell metabolism is gaining momentum. However, when establishing preclinical studies and clinical trials, it is often neglected that a tumor mass is a complex system in which cancer cells coexist and interact with several types of microenvironment populations, including endothelial cells, fibroblasts and immune cells. We are just starting to understand how such populations are affected by the metabolic changes occurring in a transformed cell and little is known about the impact of metabolism‐targeting drugs on the non‐malignant tumor components. Here we provide a general overview of the links between cancer cell metabolism and tumor microenvironment (TME), particularly focusing on the emerging literature reporting TME‐specific effects of metabolic therapies

Muon Catalyzed Fusion in 3 K Solid Deuterium

Muon catalyzed fusion in deuterium has traditionally been studied in gaseous and liquid targets. The TRIUMF solid-hydrogen-layer target system has been used to study the fusion reaction rates in the solid phase of D_2 at a target temperature of 3 K. Products of two distinct branches of the reaction were observed; neutrons by a liquid organic scintillator, and protons by a silicon detector located inside the target system. The effective molecular formation rate from the upper hyperfine state of $\mu d$ and the hyperfine transition rate have been measured: $\tilde{\lambda}_(3/2)=2.71(7)_{stat.}(32)_{syst.} \mu/s$, and $\tilde{\lambda}_{(3/2)(1/2)} =34.2(8)_{stat.}(1)_{syst.} \mu /s$. The molecular formation rate is consistent with other recent measurements, but not with the theory for isolated molecules. The discrepancy may be due to incomplete thermalization, an effect which was investigated by Monte Carlo calculations. Information on branching ratio parameters for the s and p wave d+d nuclear interaction has been extracted.Comment: 19 pages, 11 figures, submitted to PRA Feb 20, 199