320 research outputs found
Collisional and molecular spectroscopy in an ultracold Bose-Bose mixture
The route toward a Bose-Einstein condensate of dipolar molecules requires the
ability to efficiently associate dimers of different chemical species and
transfer them to the stable rovibrational ground state. Here, we report on
recent spectroscopic measurements of two weakly bound molecular levels and
newly observed narrow d-wave Feshbach resonances. The data are used to improve
the collisional model for the Bose-Bose mixture 41K87Rb, among the most
promising candidates to create a molecular dipolar BEC.Comment: 13 pages, 3 figure
Molecular signature of retinoic acid treatment in acute promyelocytic leukemia
Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia characterized by a block of differentiation at the promyelocytic stage. APL patients respond to pharmacological concentrations of all-trans retinoic acid ( RA) and disease remission correlates with terminal differentiation of leukemic blasts. The PML/RAR oncogenic transcription factor is responsible for both the pathogenesis of APL and for its sensitivity to RA. In order to identify physiological targets of RA therapy, we analysed gene expression profiles of RA-treated APL blasts and found 1056 common target genes. Comparing these results to those obtained in RA-treated U937 cell lines revealed that transcriptional response to RA is largely dependent on the expression of PML/RAR. Several genes involved in the control of differentiation and stem cell renewal are early targets of RA regulation, and may be important effectors of RA response. Modulation of chromatin modifying genes was also observed, suggesting that specific structural changes in local chromatin domains may be required to promote RA-mediated differentiation. Computational analysis of upstream genomic regions in RA target genes revealed nonrandom distribution of transcription factor binding sites, indicating that specific transcriptional regulatory complexes may be involved in determining RA response
Loading and cooling in an optical trap via hyperfine dark states
We present an optical cooling scheme that relies on hyperfine dark states to enhance loading and cooling atoms inside deep optical dipole traps. We demonstrate a sevenfold increase in the number of atoms loaded in the conservative potential with strongly shifted excited states. In addition, we use the energy selective dark state to efficiently cool the atoms trapped inside the conservative potential rapidly and without losses. Our findings open the door to optically assisted cooling of trapped atoms and molecules which lack the closed cycling transitions normally needed to achieve low temperatures and the high initial densities required for evaporative cooling
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Observation of discrete, vortex light bullets
We report the first experimental observation of vortex light bullets that are discrete, spatiotemporal, solitary waves with orbital angular momentum. We analyze conditions for their existence and investigate their rich properties and dynamics. Vortex light bullets are excited in fiber arrays with spatially shaped femtosecond pulses and analyzed with a spatiotemporal cross correlator. Most importantly, we find that they have entirely new stability properties, being robust against considerable degrees of perturbation in a limited range of energies. All experimental findings are backed up by rigorous simulations, giving further insight into the rich dynamics of vortex light bullets
Mitral regurgitation due to caseous calcification of the mitral annulus: two case reports
Caseous calcification is a rare variant of mitral annular calcification, occurring in about 0.06% of echocardiographic studies performed. It is usually a benign lesion, but it should be differentiated by abscess and tumors. Echocardiography is the most sensitive method to identify caseous calcification which appears typically as a round, calcified mass with an echo-lucent, liquid-like inner part
Kinerja Akustik dan Mekanik Panel Sandwich Berbasis Ampas Tebu dan Bambu
Telah dilakukan pengujian kinerja akustik dan kinerja mekanik panel sandwich berbasis ampas tebu dan bambu. Pengujian kinerja akustik dilakukan secara eksperimen mengacu pada prosedur ASTM E-1050-98dan kinerja mekanik menggunakan material testing machine. Pada penelitian ini dilakukan variasi ketebalan komposit ampas tebu dan pengaruh penambahan lapisan bambu di permukaan atas dan bawah komposit ampas tebu. Hasil penelitian menunjukkan bahwa pengaruh ketebalan sampel adalah menggeser penyerapan bunyi efektif pada frekuensi rendah sedangkan penambahan lapisan bambu pada komposit ampas tebu mempengaruhi penurunan nilai koefisien serapan bunyi yang dikarenakan tingkat kekerasan tinggi dan porositas rendah pada lapisan bambu. Adapun pengaruh ketebalan terhadap kinerja mekaniknya adalah menurunkan nilai MOR dan MOE sementara pengaruh penambahan lapisan bambu membuat nilai MOR naik dan nilai MOE turun. Pengaruh ketebalan dan penambahan lapisan bambu juga mengubah nilai densitas sampel.AbstractSound absorption performance and mechanical performance have been conducted in panel sandwich based bagasse and bamboo. The testing acoustic performance was conducted experimentally refer to ASTM E-1050-98 standard procedure and mechanical performance using a material testing machine. In this research, thickness variation bagasse composite and bamboo effect of adding a layer on the surface of the upper and lower composite bagasse. The results showed that the influence of the thickness of the sample is to shift the effective sound absorption at low frequencies while adding a layer of bamboo composite bagasse impairment affects the sound absorption coefficient due to a high degree of hardness and low porosity of the lining of bamboo. The effect of thickness on the mechanical performance is to lower the value of MOR and MOE while the effect of adding a layer of bamboo create value MOR MOE values rise and fall. The influence of the layer thickness and the addition of bamboo also change the value of the density of the sample
Collective oscillations of two colliding Bose-Einstein condensates
Two 87Rb condensates (F=2, m_f=2 and m_f=1) are produced in highly displaced
harmonic traps and the collective dynamical behaviour is investigated. The
mutual interaction between the two condensates is evidenced in the
center-of-mass oscillations as a frequency shift of 6.4(3)%. Calculations based
on a mean-field theory well describe the observed effects of periodical
collisions both on the center-of-mass motion and on the shape oscillations.Comment: 5 pages, 3 figures, revtex - revised versio
Observation of energetic terahertz pulses from relativistic solid density plasmas
We report the first experimental observation of terahertz (THz) radiation from the rear surface of a solid target while interacting with an intense laser pulse. Experimental and two-dimensional particle-in-cell simulations show that the observed THz radiation is mostly emitted at large angles to the target normal. Numerical results point out that a large part of the emission originates from a micron-scale plasma sheath at the rear surface of the target, which is also responsible for the ion acceleration. This opens a perspective for the application of THz radiation detection for on-site diagnostics of particle acceleration in laser-produced plasmas
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