Effects of aromatizable and nonaromatizable androgens on the sex inversion of red-spotted grouper (Epinephelus akaara)

The effects of aromatizable 17α-methyltestosterone (MT) and non-aromatizable 17α-methyldihydrotestosterone (MDHT) on sex inversion in red-spotted grouper, Epinephelus akaara, were investigated. Fish were implanted with MT, MDHT and MT+AI (aromatase inhibitor, AI) respectively for one month. The results showed that the three treated groups turned into transitional stage with intersex gonads, which contained atretic oocytes and spermatogenic germ cells at all stages of spermatogenesis. The controls did not change sex. The gonads of more than half MT-implanted fish were in early transitional stages of sex inversion, whereas those of more than half MDHT and MT+AI-implanted fish were in late transitional stages of sex inversion. No difference in serum estradiol-17β (E2) levels between the controls and the treated groups were observed, whereas 11-ketotestosterone (11-KT) and testosterone (T) levels increased in all treated groups. Significantly lower gonadosomatic index (GSI) and gonadal aromatase activity were observed in the treated groups, which were in accordance with the lower mRNA expression of P450aromA. However, P450aromB mRNA expression increased in the MT group, while it did not change in the MDHT group. These results suggest that the sex inversion of red-spotted grouper by MT and MDHT implantation might be due to the suppression of P450aromA gene expression, and resulting in both the decrease of the ovarian estrogen –secretion, as well as the increase in the 11-KT levels. Furthermore, the main reason for MT being less effective than MDHT might be due to partial aromatization of MT to estrogen

Epimedium brevicornu Maxim extract shows protective activity against Alzheimer's disease in mice

Purpose: To investigate the protective effect of Epimedium brevicornu Maxim extract (EBME) against Alzheimer's disease in 3xTg-AD mice. Methods: The cognitive function of 3xTg-AD mice was assessed using Morris water maze test. The levels of amyloid beta deposits and NeuN in the mouse hippocampus were evaluated by immunohistochemistry. Brain neurotrophic-derived factor (BDNF) and tyrosine kinase B (TrkB) expressions were examined by western blot analysis. Results: EBME treatment significantly ameliorated learning and memory deficits in AD mice, as shown by the increased time spent in the target zone during probe tests. Compared with the 3xTg-AD mice (8.4 ± 1.1 s), the escape latency in animals treated with 600 mg/kg EBME (21.5 ± 1.1 s) was significantly increased (p < 0.01). In addition, EBME significantly decreased Aβ deposits, increased NeuN-positive cells, and upregulated the expressions of BDNF (1.5 ± 0.2, p < 0.05) and TrkB (1.6 ± 0.2, p < 0.05) in the 3xTg AD mice. Conclusion: EBME treatment may be a useful therapeutic strategy for managing memory impairment

Training certified detectives to track down the intrinsic shortcuts in COVID-19 chest x-ray data sets

Deep learning faces a significant challenge wherein the trained models often underperform when used with external test data sets. This issue has been attributed to spurious correlations between irrelevant features in the input data and corresponding labels. This study uses the classification of COVID-19 from chest x-ray radiographs as an example to demonstrate that the image contrast and sharpness, which are characteristics of a chest radiograph dependent on data acquisition systems and imaging parameters, can be intrinsic shortcuts that impair the model\u27s generalizability. The study proposes training certified shortcut detective models that meet a set of qualification criteria which can then identify these intrinsic shortcuts in a curated data set

Sub-structure characteristic mode analysis of microstrip antennas using a global multi-trace formulation

A characteristic mode (CM) method that relies on a global multi-trace formulation (MTF) of surface integral equations is proposed to compute the modes and the resonance frequencies of microstrip patch antennas with finite dielectric substrates and ground planes. Compared to the coupled formulation of electric field and Poggio-Miller-Chang-Harrington-Wu-Tsai integral equations, global MTF allows for more direct implementation of a sub-structure CM method. This is achieved by representing the coupling of the electromagnetic fields on the substrate and ground plane in the form of a numerical Green function matrix, which yields a more compact generalized eigenvalue equation. The resulting sub-structure CM method avoids the cumbersome computation of the multilayered medium Green function (unlike the CM methods that rely on mixed-potential integral equations) and the volumetric discretization of the substrate (unlike the CM methods that rely on volume-surface integral equations), and numerical results show that it is a reliable and accurate approach to predicting the modal behavior of electromagnetic fields on practical microstrip antennas

Identifying the Riemann zeros by periodically driving a single qubit

The Riemann hypothesis, one of the most important open problems in pure mathematics, implies the most profound secret of prime numbers. One of the most interesting approaches to solve this hypothesis is to connect the problem with the spectrum of the physical Hamiltonian of a quantum system. However, none of the proposed quantum Hamiltonians have been experimentally feasible.Here, we report the first experiment to identify the first non-trivial zeros of the Riemann zeta function and the first two zeros of P\'olya's fake zeta function, using a novel Floquet method, through properly designed periodically driving functions. According to this method, the zeros of these functions are characterized by the occurrence of crossings of quasi-energies when the dynamics of the system are frozen. The experimentally obtained zeros are in excellent agreement with their exact values. Our study provides the first experimental realization of the Riemann zeros, which may provide new insights into this fundamental mathematical problem.Comment: 5 pages, 7 figure

Ball-milling properties and sintering behavior of Fe-Tm 2 O 3 mixture powders

Abstract(#br)Aimed at the existing problems of current neutron absorbers that were used in control rods to safely operate a nuclear reactor, new type of Fe-based Tm 2 O 3 composites and Fe-based TmFeO 3 composites, which were synthesized from the Fe-25.68 wt.%Tm 2 O 3 mixture powders by ball milling, cold isostatic pressing and sintering, were designed as next generation neutron absorbers in the present work. During ball milling, Tm 2 O 3 was fined, nano-crystallized, amorphized and then dissolved into Fe crystal lattice to form Fe (Tm, O) nanocrystalline solid solution. The effect of sintering temperature and oxygen content at sintering environment on the phases of the sintered bulks were researched, and the corresponding mechanism was discussed. Nanoscale TmFeO 3 and Tm 2 O 3 particles were distributed in the sintered bulk matrix. The microhardness, compression strength, and the coefficients of thermal expansion of the bulks sintered at different conditions were measured and discussed. The coefficient of linear expansion and compressive strength increased with increasing ball-milling time. The microhardness increased with increasing sintering temperature when the temperature was lower than 1200 °C. Meanwhile, the microhardness and compressive strength of Fe-based Tm 2 O 3 composites were larger than that of Fe-based TmFeO 3 composites, opposite for the coefficients of thermal expansion

Re-appearance of precipitated aragonite crystal fans as evidence for expansion of oceanic dissolved inorganic carbon reservoir in the aftermath of the Lomagundi-Jatuli Event

The initial accumulation of atmospheric oxygen is marked by the unprecedented positive δ13Ccarb excursions of the Lomagundi-Jatuli Event (LJE) and records an interval of abnormal O2 production through elevated rates of organic carbon burial. Emerging evidence suggests that the post-LJE atmosphere-ocean system might have suffered a significant deoxygenation. These dynamic perturbations in the oceanic redox state and biogeochemical cycles would have led to fundamental changes in carbonate precipitation dynamics. Here, we report the discovery of centimeter-sized crystal fans in the post-LJE Huaiyincun Formation, Hutuo Supergroup in the North China Craton. The hexagonal cross-sections and square terminations suggest that these fan-like dolomitic structures were originally aragonite crystal fans (ACF). Variations of stromatolite morphology and frequent occurrences of storm-related deposits in the Huaiyincun Formation point to repeated cycles of sea level changes. The bedding-parallel distribution of the ACF and the homogeneous δ13C values of the ACF-bearing dolostones are consistent with a primary depositional origin for the ACF. An updated compilation of published records of ACF throughout geological history highlights a clear absence of ACF from the initiation of the Paleoproterozoic Great Oxidation Event until the end of the LJE, and a global reappearance of ACF in the post-LJE late Paleoproterozoic. We propose that the reappearance of ACF is in agreement with the expansion of the oceanic dissolved inorganic carbon reservoir. At the same time, consumption of dissolved oxygen during the oxidation of organic matter might have been stimulated by ferruginous deep seawater, facilitating the formation of Huiayincun ACF