55 research outputs found

    Coherent strong-field control of multiple states by a single chirped femtosecond laser pulse

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    We present a joint experimental and theoretical study on strong-field photo-ionization of sodium atoms using chirped femtosecond laser pulses. By tuning the chirp parameter, selectivity among the population in the highly excited states 5p, 6p, 7p and 5f, 6f is achieved. Different excitation pathways enabling control are identified by simultaneous ionization and measurement of photoelectron angular distributions employing the velocity map imaging technique. Free electron wave packets at an energy of around 1 eV are observed. These photoelectrons originate from two channels. The predominant 2+1+1 Resonance Enhanced Multi-Photon Ionization (REMPI) proceeds via the strongly driven two-photon transition 4s←←3s4s\leftarrow\leftarrow3s, and subsequent ionization from the states 5p, 6p and 7p whereas the second pathway involves 3+1 REMPI via the states 5f and 6f. In addition, electron wave packets from two-photon ionization of the non-resonant transiently populated state 3p are observed close to the ionization threshold. A mainly qualitative five-state model for the predominant excitation channel is studied theoretically to provide insights into the physical mechanisms at play. Our analysis shows that by tuning the chirp parameter the dynamics is effectively controlled by dynamic Stark-shifts and level crossings. In particular, we show that under the experimental conditions the passage through an uncommon three-state "bow-tie" level crossing allows the preparation of coherent superposition states

    Wnt signaling in triple-negative breast cancer

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    Wnt signaling regulates a variety of cellular processes, including cell fate, differentiation, proliferation and stem cell pluripotency. Aberrant Wnt signaling is a hallmark of many cancers. An aggressive subtype of breast cancer, known as triple-negative breast cancer (TNBC), demonstrates dysregulation in canonical and non-canonical Wnt signaling. In this review, we summarize regulators of canonical and non-canonical Wnt signaling, as well as Wnt signaling dysfunction that mediates the progression of TNBC. We review the complex molecular nature of TNBC and the emerging therapies that are currently under investigation for the treatment of this disease

    Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease

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    Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1ÎČ, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1ÎČ innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.

    Photothermoelectric (PTE) detection of phase transitions. Application to triglycinesulphate (TGS)

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    A recently introduced photothermal method, the photothermoelectric (PTE) calorimetry is proposed for the first time in order to detect phase transitions. The capability of both back (BPTE) and front (FPTE) detection configurations in detecting phase transitions is analyzed. It was found that the back detection configuration, with optically opaque sample and thermally thick sample and TE sensor, is very suitable for phase transitions detection; the information, in this configuration, can be collected from both amplitude and phase of the BPTE signal and the amplitude has the possibility of amplifying the critical anomaly of the thermal parameters. In the FPTE configuration, the information about phase transition is contained only in the amplitude of the signal. Using the PTE method, the well-known ferro-paraelectric phase transition of triglycinesulphate (TGS), tacking place at about 49 °C, was investigated. Comparison with the photopyroelectric (PPE) method is performed. © 2015 Elsevier B.V. All rights reserved

    Photothermoelectric (PTE) detection of phase transitions. Application to triglycinesulphate (TGS)

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    International audienceA recently introduced photothermal method, the photothermoelectric (PTE) calorimetry is proposed for the first time in order to detect phase transitions. The capability of both back (BPTE) and front (FPTE) detection configurations in detecting phase transitions is analyzed. It was found that the back detection configuration, with optically opaque sample and thermally thick sample and TE sensor, is very suitable for phase transitions detection; the information, in this configuration, can be collected from both amplitude and phase of the BPTE signal and the amplitude has the possibility of amplifying the critical anomaly of the thermal parameters. In the FPTE configuration, the information about phase transition is contained only in the amplitude of the signal. Using the PTE method, the well-known ferro-paraelectric phase transition of triglycinesulphate (TGS), tacking place at about 49 °C, was investigated. Comparison with the photopyroelectric (PPE) method is performed. © 2015 Elsevier B.V. All rights reserved

    Photothermoelectric (PTE) versus photopyroelectric (PPE) detection of phase transitions

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    The photopyroelectric (PPE) technique is one of the photothermal (PT) methods mostly used for phase transitions investigations. In this paper, we want to compare the PPE results with those obtained using another, recently developed PT method [the photothermoelectric (PTE) calorimetry] for the same purpose of detecting phase transitions. The well-known ferro-paraelectric phase transition of TGS, taking place at a convenient temperature (about 49°C), has been selected for demonstration. A comparison of the two PPE and PTE methods, both in the back detection configuration (in the special case of optically opaque sample and thermally thick regime for both sensors and sample) shows that they are equally suitable for phase transitions detection. Performing a proper calibration, the amplitude and phase of the signals can be used in order to obtain the critical behaviour of all sample’s static and dynamic thermal parameters. © Springer Science+Business Media New York 2016
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