387 research outputs found
Theory of multiwave mixing and decoherence control in qubit array system
We develop a theory to analyze the decoherence effect in a charged qubit
array system with photon echo signals in the multiwave mixing configuration. We
present how the decoherence suppression effect by the {\it bang-bang} control
with the pulses can be demonstrated in laboratory by using a bulk
ensemble of exciton qubits and optical pulses whose pulse area is even smaller
than . Analysis is made on the time-integated multiwave mixing signals
diffracted into certain phase matching directions from a bulk ensemble.
Depending on the pulse interval conditions, the cross over from the decoherence
acceleration regime to the decoherence suppression regime, which is a peculiar
feature of the coherent interaction between a qubit and the reservoir bosons,
may be observed in the time-integated multiwave mixing signals in the realistic
case including inhomogeneous broadening effect. Our analysis will successfully
be applied to precise estimation of the reservoir parameters from experimental
data of the direction resolved signal intensities obtained in the multiwave
mixing technique.Comment: 19 pages, 11 figure
Bilateral Cataract in a Cynomolgus Monkey
Severe bilateral cataract was found in a 7 year-old naïve female cynomolgus monkey
(Macaca fascicularis) 3 months before necropsy. During macroscopic
examination, severe opacity and thinning of the lens were observed in both eyes.
Histopathology revealed that the lens nuclei and majority of cortex lens fibers had
disappeared and become excavated, while the lens fibers in the subcapsular area were
swollen and distorted. Other observations included atrophy and vacuolation in the lens
epithelial cells and proliferation of spindle cells and collagen fiber beneath the
anterior capsule of the right eye. Immunohistochemical staining of these spindle cells
revealed the presence of vimentin, cytokeratin and α-smooth muscle actin (α-SMA), which
were considered to be derived from lens epithelial cells. This is a rare case of
spontaneous, bilateral, hypermature cataract in a cynomolgus monkey
Lineage-Specific Profiling Delineates the Emergence and Progression of Naive Pluripotency in Mammalian Embryogenesis.
Naive pluripotency is manifest in the preimplantation mammalian embryo. Here we determine transcriptome dynamics of mouse development from the eight-cell stage to postimplantation using lineage-specific RNA sequencing. This method combines high sensitivity and reporter-based fate assignment to acquire the full spectrum of gene expression from discrete embryonic cell types. We define expression modules indicative of developmental state and temporal regulatory patterns marking the establishment and dissolution of naive pluripotency in vivo. Analysis of embryonic stem cells and diapaused embryos reveals near-complete conservation of the core transcriptional circuitry operative in the preimplantation epiblast. Comparison to inner cell masses of marmoset primate blastocysts identifies a similar complement of pluripotency factors but use of alternative signaling pathways. Embryo culture experiments further indicate that marmoset embryos utilize WNT signaling during early lineage segregation, unlike rodents. These findings support a conserved transcription factor foundation for naive pluripotency while revealing species-specific regulatory features of lineage segregation.We thank Peter Humphreys for assistance with imaging, and Samuel Jameson and staff for mouse husbandry. We are grateful to Charis Drummer, Ayako Sedohara, Akiko Shimada, Yuko Yamada, Ryo Oiwa, and Takeshi Kuge for technical support with marmoset embryo recovery. Illumina sequencing was provided by Bettina Haase and Dinko Pavlinic at the EMBL Genomics Core Facility. This work was supported by funding from the Wellcome Trust, the Genome Biology Unit of the European Molecular Biology Laboratory, BBSRC grants BB/G015678/1 and BB/M004023/1, an MRC Centenary Award, and the Louis Jeantet Foundation. A.S. is a Medical Research Council Professor.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.devcel.2015.10.01
Tissue flow regulates planar cell polarity independently of the Frizzled core pathway
Planar cell polarity (PCP) regulates the orientation of external structures. A core group of proteins that includes Frizzled forms the heart of the PCP regulatory system. Other PCP mechanisms that are independent of the core group likely exist, but their underlying mechanisms are elusive. Here, we show that tissue flow is a mechanism governing core group-independent PCP on the Drosophila notum. Loss of core group function only slightly affects bristle orientation in the adult central notum. This near-normal PCP results from tissue flow-mediated rescue of random bristle orientation during the pupal stage. Manipulation studies suggest that tissue flow can orient bristles in the opposite direction to the flow. This process is independent of the core group and implies that the apical extracellular matrix functions like a “comb” to align bristles. Our results reveal the significance of cooperation between tissue dynamics and extracellular substances in PCP establishment
Minimal upstream open reading frame of Per2 mediates phase fitness of the circadian clock to day/night physiological body temperature rhythm
全身の体内リズムを調和させるRNA配列の発見 --体温の日内変化に合わせてしなやかに調和させる--. 京都大学プレスリリース. 2023-03-07.Body temperature in homeothermic animals does not remain constant but displays a regular circadian fluctuation within a physiological range (e.g., 35°C–38.5°C in mice), constituting a fundamental systemic signal to harmonize circadian clock-regulated physiology. Here, we find the minimal upstream open reading frame (uORF) encoded by the 5′ UTR of the mammalian core clock gene Per2 and reveal its role as a regulatory module for temperature-dependent circadian clock entrainment. A temperature shift within the physiological range does not affect transcription but instead increases translation of Per2 through its minimal uORF. Genetic ablation of the Per2 minimal uORF and inhibition of phosphoinositide-3-kinase, lying upstream of temperature-dependent Per2 protein synthesis, perturb the entrainment of cells to simulated body temperature cycles. At the organismal level, Per2 minimal uORF mutant skin shows delayed wound healing, indicating that uORF-mediated Per2 modulation is crucial for optimal tissue homeostasis. Combined with transcriptional regulation, Per2 minimal uORF-mediated translation may enhance the fitness of circadian physiology
Porencephaly in a Cynomolgus Monkey (Macaca Fascicularis)
Porencephaly was observed in a female cynomolgus monkey (Macaca fascicularis) aged 5 years and 7 months. The cerebral hemisphere exhibited diffuse brownish excavation with partial defects of the full thickness of the hemispheric wall, and it constituted open channels between the lateral ventricular system and arachnoid space. In addition, the bilateral occipital lobe was slightly atrophied. Histopathologically, fibrous gliosis was spread out around the excavation area and its periphery. In the roof tissue over the cavity, small round cells were arranged in the laminae. They seemed to be neural or glial precursor cells because they were positive for Musashi 1 and negative for NeuN and GFAP. In the area of fibrous gliosis, hemosiderin or lipofuscin were deposited in the macrophages, and activated astroglias were observed extensively around the excavation area
Dysregulated Aire expression and autoimmunity
Deficiency for AIRE/Aire in both humans and mice results in the development of organ-specific autoimmune disease. We tested whether augmented and/or dysregulated AIRE/Aire expression might be also prone to the breakdown of self-tolerance. To define the effect of augmented Aire expression on the development of autoimmunity, antigen-specific clonal deletion and production of clonotypic regulatory T cells (Tregs) in the thymus were examined using mice expressing two additional copies of Aire in a heterozygous state (3xAire-knockin mice: 3xAire-KI). We found that both clonal deletion of autoreactive T cells and production of clonotypic Tregs in the thymus from 3xAire-KI were impaired in a T-cell receptor-transgenic system. Furthermore, 3xAire-KI females showed higher scores of experimental autoimmune encephalomyelitis induced by myelin oligodendrocyte glycoprotein than wild-type littermates, suggesting that augmented Aire expression exacerbates organ-specific autoimmunity under disease-prone conditions. In humans, we found that one patient with amyopathic dermatomyositis showed CD3–CD19– cells expressing AIRE in the peripheral blood before the treatment but not during the remission phase treated with immunosuppressive drugs. Thus, not only loss of function of AIRE/Aire but also augmented and/or dysregulated expression of AIRE/Aire should be considered for the pathogenesis of organ-specific autoimmunity. We suggest that further analyses should be pursued to establish a novel link between organ-specific autoimmune disease and dysregulated AIRE expression in clinical settings
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