Stochastic light concentration from 3D to 2D reveals ultraweak chemi- and bioluminescence

For countless applications in science and technology, light must be concentrated, and concentration is classically achieved with reflective and refractive elements. However, there is so far no efficient way, with a 2D detector, to detect photons produced inside an extended volume with a broad or isotropic angular distribution. Here, with theory and experiment, we propose to stochastically transform and concentrate a volume into a smaller surface, using a high- albedo Ulbricht cavity and a small exit orifice through cavity walls. A 3D gas of photons produced inside the cavity is transformed with a 50% number efficiency into a 2D Lambertian emitting orifice with maximal radiance and a much smaller size. With high-albedo quartz-powder cavity walls ( P = 99.94%), the orifice area is 1/( 1 - P) approximate to 1600 times smaller than the walls' area. When coupled to a detectivity-optimized photon-counter ( D = 0.015 photon- 1 s1/ 2 cm) the detection limit is 110 photon s- 1 L- 1. Thanks to this unprecedented sensitivity, we could detect the luminescence produced by the non-catalytic disproportionation of hydrogen peroxide in pure water, which has not been observed so far. We could also detect the ultraweak bioluminescence produced by yeast cells at the onset of their growth. Our work opens new perspectives for studying ultraweak luminescence, and the concept of stochastic 3D/2D conjugation should help design novel light detection methods for large samples or diluted emitters

Behavioral characteristics of the offspring of adolescent rats

The aim of this study was to test the hypothesis that, during adulthood, the offspring of adolescent rats differ in emotionality, learning and memory from the offspring of adult rats. The behavior of the offspring of adolescent (age, 50-55 days) and adult rats (age, 90-95 days) was tested in the open field, activity cage, and passive and active avoidance apparatus. The latencies during training and testing in the passive avoidance apparatus of the offspring of adolescent parents were shorter than the latencies of control offspring (P<0.001 on both training and testing days). Offspring of adolescent parents showed shorter latency time in acquisition trials during active avoidance testing compared to control offspring (P<0.001). They also showed a higher number of active avoidance responses in the last four blocks of acquisition (P<0.001) and first two blocks of extinction trials (P<0.05 and P<0.001, respectively). The offspring of adolescent parents showed higher latency on the first day of testing in the open field (P<0.01) and a lower latency on the third day of testing (P<0.01). They also showed higher activity during all three days of testing (1st and 2nd day: P<0.01; 3rd day: P<0.05). The spontaneous activity of the offspring of adolescent parents in the activity cage was higher in the last three intervals of testing (P<0.001). In summary, the offspring of adolescent parents were less anxious and tended to be more active. The results of two learning and memory tests were opposite, but could be explained by a higher exploratory drive of the offspring of adolescent parents. This was probably due to chronic malnutrition stress and the disturbed mother-infant relationship in the litters of adolescent mothers

Structural characterisation of Cu-Zr thin film combinatorial libraries with synchrotron radiation at the limit of crystallinity

We report for the first-time combinatorial synthesis of thin film metallic glass libraries via magnetron co-sputtering at the limit of crystallinity. Special care was taken to prepare extremely pure CuZr films (1–2 µm thickness) with large compositional gradients (Cu18.2Zr81.8 to Cu74.8Zr25.2) on X-ray transparent polymer substrates in high-vacuum conditions. Combined mapping of atomic structure (synchrotron radiation) and chemical composition (X-ray fluorescence spectroscopy) revealed that over the entire composition range, covering multiple renowned glass formers, two phases are present in the film. Our high-resolution Synchrotron approach identified the two phases as: untextured amorphous Cu51Zr14 (cluster size 1.3 nm) and textured, nanocrystalline α-Zr (grain size 1–5 nm). Real space HR-STEM analyses of a representative composition substantiate our XRD results. Determined cluster and grain sizes are below the resolution limit of conventional laboratory-scale X-ray diffractometers. The presented phase mixture is not permitted in the Cu-Zr phase diagram and contrary to existing literature. The phase ratio follows a linear trend with amorphous films on the Cu-rich side and increasing amounts of α-Zr with increasing Zr content. While cluster size and composition of the amorphous phase remain constant thorough the compositional gradient, crystallite size and texture of the nanocrystalline α-Zr change as a function of Zr content

Short- and Long-Term Consequences of Corticotropin-Releasing Factor in Early Development

Corticotropin-releasing factor (CRF) mediates various stress-related responses in adult animals. Little is known about the effects of CRF during early development. Young mammals often vocalize when isolated in novel surroundings. Heightened levels of CRF inhibit vocalizing in isolated rat and guinea pig pups. Still lower levels of CRF may facilitate or permit vocalizing in rat pups. In guinea pigs, CRF appears to move pups from an initial active, to a subsequent passive, stage of behavioral responsiveness. CRF activity prior to birth can also affect the young. Exposing pregnant female rats to stressors during the last trimester of pregnancy alters the morphological and behavioral development of the offspring. Effects of gestational stress can be mimicked by injecting pregnant females with CRF during the last trimester. CRF appears to mediate both short- and long-term responses to stressors during development in rodents

Oxidative Stress and Cancer Heterogeneity Orchestrate NRF2 Roles Relevant for Therapy Response

Oxidative stress and its end-products, such as 4-hydroxynonenal (HNE), initiate activation of the Nuclear Factor Erythroid 2-Related Factor 2 (NRF2)/KEAP1 signaling pathway that plays a crucial role in the maintenance of cellular redox homeostasis. However, an involvement of 4-HNE and NRF2 in processes associated with the initiation of cancer, its progression, and response to therapy includes numerous, highly complex events. They occur through interactions between cancer and stromal cells. These events are dependent on many cell-type specific features. They start with the extent of NRF2 binding to its cytoplasmic repressor, KEAP1, and extend to the permissiveness of chromatin for transcription of ARE-containing genes that are NRF2 targets. This review will explore epigenetic molecular mechanisms of NRF2 transcription through the specific molecular anatomy of its promoter. It will explain the role of NRF2 in cancer stem cells, with respect to cancer therapy resistance. Additionally, it also discusses NRF2 involvement at the cross-roads of communication between tumor associated inflammatory and stromal cells, which is also an important factor involved in the response to therapy