A method of fabricating multilayer focusing mirrors that can focus X-rays down to 10 nm or less was established in this study. The wavefront aberration induced by multilayer Kirkpatrick-Baez mirror ...optics was measured using a single grating interferometer at a photon energy of 9.1 keV at SPring-8 Angstrom Compact Free Electron Laser (SACLA), and the mirror shape was then directly corrected by employing a differential deposition method. The accuracies of these processes were carefully investigated, considering the accuracy required for diffraction-limited focusing. The wavefront produced by the corrected multilayer focusing mirrors was characterized again in the same manner, revealing that the root mean square of the wavefront aberration was improved from 2.7 (3.3) rad to 0.52 (0.82) rad in the vertical (horizontal) direction. A wave-optical simulator indicated that these wavefront-corrected multilayer focusing mirrors are capable of achieving sub-10-nm X-ray focusing.
Polycyclic aromatic hydrocarbons (PAHs) are organic compounds which may be present as contaminants in wastewater sewage sludge. Due to their toxicity and persistence in the solid phase, information ...should be gathered relating to their presence in sewage sludge in order to determine their contamination risks after land application. In this study, sewage sludge samples from nine Tunisian wastewater treatment plants (WWTPs) were characterized for the total content in 16 EPA-priority PAHs using an optimized extraction protocol. These WWTPs differ in the type of applied treatment and the wastewater source. Through this first assessment of PAHs in Tunisian sludges, their total concentration varied from 96 to the highest level of 7718
ng
g
−1. Regardless of the source of wastewater, the highest PAH content was found in sludges deriving from untreated wastewater (natural lagooning). In addition, some correlation was found between the distribution patterns of each PAH, the type of applied treatment on one hand and the wastewater source on other hand.
Pulsatile release of gonadotrophin‐releasing hormone (GnRH) is indispensable to maintain normal gonadotrophin secretion. The pulsatile secretion of GnRH is associated with synchronised electrical ...activity in the mediobasal hypothalamus (i.e. multiple unit activity; MUA), which is considered to reflect the rhythmic oscillations in the activity of the neuronal network that drives pulsatile GnRH secretion. However, the cellular source of this ultradian rhythm in GnRH activity is unknown. Direct input from kisspeptin neurones in the arcuate nucleus (ARC) to GnRH cell bodies in the medial preoptic area or their terminals in the median eminence could be the intrinsic source for driving the GnRH pulse generator. To determine whether kisspeptin signalling could be responsible for producing pulsatile GnRH secretion, we studied goats, measured plasma levels of luteinising hormone (LH) and recorded MUA in the posterior ARC, where the majority of kisspeptin neuronal cell bodies are located. Rhythmic volleys of MUA were found to be accompanied by LH pulses with regular intervals in the ARC, where kisspeptin neuronal cell bodies were found. Exogenous administration of kisspeptin stimulated a sustained increase in LH secretion, without influencing MUA, suggesting that the GnRH pulse generator, as reflected by MUA, originated from outside of the network of GnRH neurones, and could plausibly reflect the pacemaker activity of kisspeptin neurones, whose projections reach the median eminence where GnRH fibres project. These observations suggest that the kisspeptin neurones in the ARC may be the intrinsic source of the GnRH pulse generator.
Background and purpose:
Neurons with atrophic neurites may remain alive and therefore may have the potential to regenerate even when neuronal death has occurred in some parts of the brain. This study ...aimed to explore effects of drugs that can facilitate the regeneration of neurites and the reconstruction of synapses even in severely damaged neurons.
Experimental approach:
We investigated the effects of extracts of Astragalus mongholicus on the cognitive defect in mice caused by injection with the amyloid peptide Aβ(25‐35). We also examined the effect of the extract on the regeneration of neurites and the reconstruction of synapses in cultured neurons damaged by Aβ(25‐35).
Key results:
A. mongholicus extract (1 g kg−1 day−1 for 15 days, p.o.) reversed Aβ(25‐35)‐induced memory loss and prevented the loss of axons and synapses in the cerebral cortex and hippocampus in mice. Treatment with Aβ(25‐35) (10 μM) induced axonal atrophy and synaptic loss in cultured rat cortical neurons. Subsequent treatment with A. mongholicus extract (100 μg/ml) resulted in significant axonal regeneration, reconstruction of neuronal synapses, and prevention of Aβ(25‐35)‐induced neuronal death. Similar extracts of A. membranaceus had no effect on axonal atrophy, synaptic loss, or neuronal death. The major known components of the extracts (astragalosides I, II, and IV) reduced neurodegeneration, but the activity of the extracts did not correlate with their content of these three astragalosides.
Conclusion and implications:
A. mongholicus is an important candidate for the treatment of memory disorders and the main active constituents may not be the known astragalosides.
British Journal of Pharmacology (2006) 149, 532–541. doi:10.1038/sj.bjp.0706865
Generally, uniformly-distributed irradiation defects such as artificial pinning centers improve the critical current, Ic, of REBCO tapes in strong external field. On the other hand, at self-field or ...low field, irradiation is not effective for improving Ic. However, if non-uniform pinning center distribution similar to vortex profile is assumed, this would increase Ic at selffield. Therefore, in this study, we experimentally investigated the effect of partial irradiation on Ic based on the assumption. We prepared REBCO tapes irradiated with trihydrogen cations in the c-axis direction. Three different patterns of defects were examined; overall, edge-only and center-only irradiations. We measured Ic at 77 K, 25 K and 15 K using the four terminal method. Results showed that, while Ic was not improved after the irradiations for each pattern, Ic behaviour depends on the patterns; edge-only-irradiated tapes showed the highest Ic and overall irradiation caused the largest Ic degradation at 77 K. However, center-only-irradiated tapes showed the lowest critical current at 25 K and 15 K which may be due to enhancement of flux pinning effect at lower temperature. Moreover, pinning centers in the edge region might be more effective to increase Ic, though further investigation on the effect of non-uniform pinning centers is required.
Heat stress disrupts reproductive function in cattle. In summer, high ambient temperature and humidity elevate core body temperature, which is considered to be detrimental to reproductive abilities ...in cattle. Neurokinin B (NKB) is a factor that generates pulsatile GnRH and subsequent LH secretion in mammals. Recent studies have reported that NKB-neurokinin 3 receptor (NK3R) signaling is associated with heat-defense responses in rodents. The present study aimed to clarify the role of NKB-NK3R signaling in thermoregulation in cattle. We examined the effects of an NK3R-selective agonist, senktide, on vaginal temperature as an indicator of core body temperature in winter and summer. In both seasons, continuous infusion of senktide for 4 h immediately decreased vaginal temperature, and the mean temperature change in the senktide-treated group was significantly lower than that of both vehicle- and GnRH-treated groups. Administration of GnRH induced LH elevation, but there was no significant difference in vaginal temperature change between GnRH- and vehicle-treated groups. Moreover, we investigated the effects of senktide on ovarian temperature. Senktide treatment seemed to suppress the increase in ovarian temperature from 2 h after the beginning of administration, although the difference between groups was not statistically significant. Taken together, these results suggest that senktide infusion caused a decline in the vaginal temperature of cattle, in both winter and summer seasons, and this effect was not due to the gonadotropin-releasing action of senktide. These findings provide new therapeutic options for senktide to support both heat-defense responses and GnRH/LH pulse generation.
•Continuous administration of senktide decreased core temperature in summer.•Core temperature change was not due to gonadotropin-releasing action of senktide.•Senktide stimulate both heat-defense responses and GnRH/LH pulse generation.
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