2,091 research outputs found

    Onset, timing, and exposure therapy of stress disorders: mechanistic insight from a mathematical model of oscillating neuroendocrine dynamics

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    The hypothalamic-pituitary-adrenal (HPA) axis is a neuroendocrine system that regulates numerous physiological processes. Disruptions in the activity of the HPA axis are correlated with many stress-related diseases such as post-traumatic stress disorder (PTSD) and major depressive disorder. In this paper, we characterize "normal" and "diseased" states of the HPA axis as basins of attraction of a dynamical system describing the inhibition of peptide hormones such as corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) by circulating glucocorticoids such as cortisol (CORT). In addition to including key physiological features such as ultradian oscillations in cortisol levels and self-upregulation of CRH neuron activity, our model distinguishes the relatively slow process of cortisol-mediated CRH biosynthesis from rapid trans-synaptic effects that regulate the CRH secretion process. Crucially, we find that the slow regulation mechanism mediates external stress-driven transitions between the stable states in novel, intensity, duration, and timing-dependent ways. These results indicate that the timing of traumatic events may be an important factor in determining if and how patients will exhibit hallmarks of stress disorders. Our model also suggests a mechanism whereby exposure therapy of stress disorders such as PTSD may act to normalize downstream dysregulation of the HPA axis.Comment: 30 pages, 16 figures, submitted to BMC Biology Direc

    Statistiques de pêche en lagune Ebrié (Côte d'Ivoire): 1976 et 1977

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    In the Ebrié lagoon fishes are mostly caught by means of 6 kinds of fishing gear: small and large mesh gillnets (respectively 1.5-2 and 6.5-8 inches stretched mesh), cast-nets and multi-hooked lines for individual fishermen, and beach seines and ring-nets for collective fishing. Statistical data gathered during 1977 allowed an estimation of total catches: about 6700 tons. The bulk of the catch, 4800 tons, came from beach nets and ring nets, the contribution of which is nearly the same. Individual fishing gear, small mesh gillnets repesenting the main part, account for 25 to 30% of total catch; about 1900 tons for year 1977. Six species, or species groups, comprise more than 85% of the catch. In the Abidjan area, where marine influence is the more noticeable, ring nets are more numerous and their catches increased since 1975. On the other hand, fish captures in unsalted and brackish waters seem to show a stagnancy and a decrease in fish lengths; this phenomenon is probably in connection with beach-seine excessive fishing effort and/or their small meshes (one inch stretched)

    Force and deflection sensor with shell membrane and optical gratings and method of manufacture

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    A sensor for force is formed from an elastomeric cylinder having a region with apertures. The apertures have passageways formed between them, and an optical fiber is introduced into these passageways, where the optical fiber has a grating for measurement of tension positioned in the passageways between apertures. Optionally, a temperature measurement sensor is placed in or around the elastomer for temperature correction, and if required, a copper film may be deposited in the elastomer for reduced sensitivity to spot temperature variations in the elastomer near the sensors

    Process for manufacturing shell membrane force and deflection sensor

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    A sensor for force is formed from an elastomeric cylinder having a region with apertures. The apertures have passageways formed between them, and an optical fiber is introduced into these passageways, where the optical fiber has a grating for measurement of tension positioned in the passageways between apertures. Optionally, a temperature measurement sensor is placed in or around the elastomer for temperature correction, and if required, a copper film may be deposited in the elastomer for reduced sensitivity to spot temperature variations in the elastomer near the sensors

    Fingertip force control with embedded fiber Bragg grating sensors

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    Abstract—We describe the dynamic testing and control results obtained with an exoskeletal robot finger with embedded fiber optical sensors. The finger is inspired by the designs of arthropod limbs, with integral strain sensilla concentrated near the joints. The use of fiber Bragg gratings (FBGs) allows for embedded sensors with high strain sensitivity and immunity to electromagnetic interference. The embedded sensors are useful for contact detection and for control of forces during fine manipulation. The application to force control requires precise and high-bandwidth measurement of contact forces. We present a nonlinear force control approach that combines signals from an optical interrogator and conventional joint angle sensors to achieve accurate tracking of desired contact forces. I

    HRAS is a therapeutic target in malignant chemo-resistant adenomyoepithelioma of the breast

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    Abstract Malignant adenomyoepithelioma (AME) of the breast is an exceptionally rare form of breast cancer, with a significant metastatic potential. Chemotherapy has been used in the management of advanced AME patients, however the majority of treatments are not effective. Recent studies report recurrent mutations in the HRAS Q61 hotspot in small series of AMEs, but there are no preclinical or clinical data showing H-Ras protein as a potential therapeutic target in malignant AMEs. We performed targeted sequencing of tumours’ samples from new series of 13 AMEs, including 9 benign and 4 malignant forms. Samples from the breast tumour and the matched axillary metastasis of one malignant HRAS mutated AME were engrafted and two patient-derived xenografts (PDX) were established that reproduced the typical AME morphology. The metastasis-derived PDX was treated in vivo by different chemotherapies and a combination of MEK and BRAF inhibitors (trametinib and dabrafenib). All malignant AMEs presented a recurrent mutation in the HRAS G13R or G12S hotspot. Mutation of PIK3CA were found in both benign and malignant AMEs, while AKT1 mutations were restricted to benign AMEs. Treatment of the PDX by the MEK inhibitor trametinib, resulted in a marked anti-tumor activity, in contrast to the BRAF inhibitor and the different chemotherapies that were ineffective. Overall, these findings further expand on the genetic features of AMEs and suggest that patients carrying advanced HRAS-mutated AMEs could potentially be treated with MEK inhibitors

    Measurement of the Branching Fraction for B- --> D0 K*-

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    We present a measurement of the branching fraction for the decay B- --> D0 K*- using a sample of approximately 86 million BBbar pairs collected by the BaBar detector from e+e- collisions near the Y(4S) resonance. The D0 is detected through its decays to K- pi+, K- pi+ pi0 and K- pi+ pi- pi+, and the K*- through its decay to K0S pi-. We measure the branching fraction to be B.F.(B- --> D0 K*-)= (6.3 +/- 0.7(stat.) +/- 0.5(syst.)) x 10^{-4}.Comment: 7 pages, 1 postscript figure, submitted to Phys. Rev. D (Rapid Communications

    Measurement of the quasi-elastic axial vector mass in neutrino-oxygen interactions

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    The weak nucleon axial-vector form factor for quasi-elastic interactions is determined using neutrino interaction data from the K2K Scintillating Fiber detector in the neutrino beam at KEK. More than 12,000 events are analyzed, of which half are charged-current quasi-elastic interactions nu-mu n to mu- p occurring primarily in oxygen nuclei. We use a relativistic Fermi gas model for oxygen and assume the form factor is approximately a dipole with one parameter, the axial vector mass M_A, and fit to the shape of the distribution of the square of the momentum transfer from the nucleon to the nucleus. Our best fit result for M_A = 1.20 \pm 0.12 GeV. Furthermore, this analysis includes updated vector form factors from recent electron scattering experiments and a discussion of the effects of the nucleon momentum on the shape of the fitted distributions.Comment: 14 pages, 10 figures, 6 table

    Study of e+e- --> pi+ pi- pi0 process using initial state radiation with BABAR

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    The process e+e- --> pi+ pi- pi0 gamma has been studied at a center-of-mass energy near the Y(4S) resonance using a 89.3 fb-1 data sample collected with the BaBar detector at the PEP-II collider. From the measured 3pi mass spectrum we have obtained the products of branching fractions for the omega and phi mesons, B(omega --> e+e-)B(omega --> 3pi)=(6.70 +/- 0.06 +/- 0.27)10-5 and B(phi --> e+e-)B(phi --> 3pi)=(4.30 +/- 0.08 +/- 0.21)10-5, and evaluated the e+e- --> pi+ pi- pi0 cross section for the e+e- center-of-mass energy range 1.05 to 3.00 GeV. About 900 e+e- --> J/psi gamma --> pi+ pi- pi0 gamma events have been selected and the branching fraction B(J/psi --> pi+ pi- pi0)=(2.18 +/- 0.19)% has been measured.Comment: 21 pages, 37 postscript figues, submitted to Phys. Rev.

    Measurement of Branching Fraction and Dalitz Distribution for B0->D(*)+/- K0 pi-/+ Decays

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    We present measurements of the branching fractions for the three-body decays B0 -> D(*)-/+ K0 pi^+/-andtheirresonantsubmodes and their resonant submodes B0 -> D(*)-/+ K*+/- using a sample of approximately 88 million BBbar pairs collected by the BABAR detector at the PEP-II asymmetric energy storage ring. We measure: B(B0->D-/+ K0 pi+/-)=(4.9 +/- 0.7(stat) +/- 0.5 (syst)) 10^{-4} B(B0->D*-/+ K0 pi+/-)=(3.0 +/- 0.7(stat) +/- 0.3 (syst)) 10^{-4} B(B0->D-/+ K*+/-)=(4.6 +/- 0.6(stat) +/- 0.5 (syst)) 10^{-4} B(B0->D*-/+ K*+/-)=(3.2 +/- 0.6(stat) +/- 0.3 (syst)) 10^{-4} From these measurements we determine the fractions of resonant events to be : f(B0-> D-/+ K*+/-) = 0.63 +/- 0.08(stat) +/- 0.04(syst) f(B0-> D*-/+ K*+/-) = 0.72 +/- 0.14(stat) +/- 0.05(syst)Comment: 7 pages, 3 figures submitted to Phys. Rev. Let
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