Optical trapping with "on-demand" two-photon luminescence using Cr:LiSAF laser with optically addressed saturable Bragg reflector

We demonstrate a diode-pumped Cr:LiSAF laser with controllable and reliable fast switching between its continuous-wave and mode-locked states of operation using an optically-addressed semiconductor Bragg reflector, permitting dyed microspheres to be continuously trapped and monitored using a standard microscope imaging and on-demand two-photon-excited luminescence techniques

Passacaglia for Strings

In Passacaglia for Strings, expressive relationships between the music in the foreground and the structural design of the piece are explored. The opening melody of the bass provides a harmonic foundation and the main source of musical material for the piece. Textural variety and changes in orchestration allow the bass player to frequently take the role of soloist, and to add a more expressive value to the melodies in the bass. The piece is ten (10) minutes in duration and consists of four sections (Section 1 mm.1-81; Section 2 mm. 82-144; Section 3 mm. 145-172; Section 4 mm. 173-232). The bass line plays a different role in each. An equally important element of the work is the melody played by the first violin in the chorale section of the piece, especially its rhythmic character, as after several refrains in the first section, the primary bass line dissolves within the chordal texture of the chorale, and allows this secondary melody to become predominant for a while. It returns in the third section of the work, but with more agitation and, lastly, goes through a short imitative episode in the fourth section of the piece, where it completely adapts the rhythmic profile of the melody from the choral section. The harmonic context of the work is primarily dictated by the presence of six distinct vertical sonorities, which move to the foreground in the middle section of the piece. The work comes to an end when the opening bass line is fully revealed in the foreground, and entirely transformed through its interaction with the melody from the chorale section

Experimental analysis of emission linewidth narrowing in a pulsed KGd(WO4)2 Raman laser

The linewidth of a KGd(WO4)2 (KGW) intracavity pumped Raman laser is analyzed experimentally for different configurations of the Raman and pump laser resonators: with narrow and broadband pump emission profiles, with and without linewidth narrowing elements in the Raman laser resonator, with and without injection seeding into the Raman cavity. The benefits of a narrow linewidth pump source in combination with linewidth narrowing elements in the Raman laser cavity for the efficient linewidth narrowing of the Raman laser emission are explained. 20 kW peak-power pulses at 1156 nm with 0.43 cm-1 emission linewidth are demonstrated from an injection seeded KGW Raman laser

Characterization of single-crystal synthetic diamond for multi-watt continuous-wave Raman lasers

A continuous-wave diamond Raman laser is demonstrated with an output power of 5.1 W at 1217 nm. This Raman laser is intracavity pumped by a side-pumped Nd:YLF rod laser: a 43-fold brightness enhancement between the Nd:YLF and diamond Raman lasers is observed, with the M2 beam propagation factor of the diamond Raman laser measured to be <; 1.2. Although higher output powers are demonstrated in a similar configuration using KGd(WO4)2 (KGW) as the Raman laser material (6.1 W), the brightness enhancement is much lower (2.5 fold) due to the poorer beam quality of the KGW Raman laser (M2 <; 6). The Raman gain coefficient of single-crystal synthetic diamond at a pump wavelength of 1064-nm is also measured: a maximum value of 21±2 cm/GW is returned compared to 5.7±0.5 cm/GW for KGW at the same wavelength

Simplified method of calorimetric measurements of background loss in crystals

We report on the measurements of absorption coefficient of the synthetic diamond crystal using an adapted form of laser calorimetry technique at wavelengths of 1064, 640, 532, 452 and 364 nm. The absorption coefficient was found to increase exponentially from 0,03 cm-1 at 1064 nm to 0,7 cm-1 at 364 nm

Large scale localization of protein phosphorylation by use of electron capture dissociation mass spectrometry.

We used on-line electron capture dissociation (ECD) for the large scale identification and localization of sites of phosphorylation. Each FT-ICR ECD event was paired with a linear ion trap collision-induced dissociation (CID) event, allowing a direct comparison of the relative merits of ECD and CID for phosphopeptide identification and site localization. Linear ion trap CID was shown to be most efficient for phosphopeptide identification, whereas FT-ICR ECD was superior for localization of sites of phosphorylation. The combination of confident CID and ECD identification and confident CID and ECD localization is particularly valuable in cases where a phosphopeptide is identified just once within a phosphoproteomics experiment

Optically-pumped saturable absorber for fast switching between continuous-wave and passively mode-locked regimes of a Nd:YVO4 laser

We report on the fast (~50 μs) remote-controlled switching between continuous-wave (cw), cw mode-locked (ML) and Q-switched ML modes of operation of a Nd:YVO4 laser using an optically-pumped saturable absorber (SA). Pulses as short as 40 ps with an average output power of 0.5 W are obtained in cw ML regime

Steady-state Raman gain in diamond as a function of pump wavelength

The variation in the Raman gain coefficient in single-crystal diamond for pump wavelengths between 355 and 1450 nm is measured. Two techniques are used: a pump-probe approach giving an absolute measurement and a stimulated Raman oscillation threshold technique giving a relative measurement. Both approaches indicate that the Raman gain coefficient is a linear function of pump wavenumber. With the pump polarized along a direction in the crystal, the Raman gain coefficient measured by the pump-probe technique is found to vary from 7.6 +/- 0.8 for a pump wavelength of 1280 nm to 78 +/- 8 cm/GW for a pump wavelength of 355 nm. With the established dependence of the Raman gain coefficient on the pump wavelength, the Raman gain coefficient can be estimated at any pump wavelength within the spectral range from 355 up to 1450 nm

Optical gain in NV- colour centres for highly-sensitive magnetometry : a theoretical study

Optical gain in an amplifier based on NV- colour centres (CC) in diamond is proposed as a new method for optical magnetic field detection. An analytical expression for magnetic field sensitivity with this method is deduced. The sensitivity is highest at the pump intensities about 100 times above the saturation intensity of NV- CC and can reach values of ~1.4 fT/√Hz in a pump-probe configuration with NV- CC concentration in diamond of 2.5 ppm. Collection efficiency of probe emission can be simpler and significantly higher than that of NV- CC luminescence, used for conventional optical magnetometry in diamond. This makes this method attractive for applications requiring remote magnetic field sensing

Expression of MDR1, LRP, BCRP and BCL-2 genes at diagnosis of childhood ALL: comparison with mrd status after induction therapy

To investigate properties of leukemic cells by sorting out children diagnosed with ALL with different response to chemotherapy based on MRD level. Methods: We used a minimal residual disease (MRD) data on day 36 obtained with 3-colour flow cytometry as a reference. In view of MRD results, we used real-time PCR to assess expression levels of multidrug resistance associated genes MDR1, LRP and BCRP, antiapoptotic gene Bcl-2 in initial samples from children diagnosed with ALL. P-gp expression and function in initial samples were analyzed by flow cytometry. Results: Briefly, medians of relative expression levels of MDR1 gene were roughly comparable and in MRD+ group came to 22.8 (0.02–26.6; n = 9) vs 24.8 (3.9–41.4; n = 10) in MRD– group. Bcl-2 gene showed tendency to higher expression levels in MRD+ group with median at 5992.9 (521.0–10362.0; n = 9) compared to 3183.6 (1947.9–6581.0; n = 10) in MRD– group. LRP gene relative expression levels were similar in both groups and came to 1934.9 (1500.7–3490.4; n = 9) and 1408.5 (665.5–2917.1; n = 10) in MRD+ and MRD– groups, respectively. The median of BCRP expression levels in MRD+ group was considerably lower than that in MRD– group, namely 76000.0 (48196.2–169230.8; n = 9) and 227967.2 (16683.7–422222.2; n = 10), respectively, but statistical analysis showed no significant difference for this parameter. Conclusion: We investigated expression of multidrug resistance genes MDR1, LRP and BCRP and antiapoptotic gene Bcl-2 in leukemic cells at diagnosis, and MRD level at the end of induction therapy, and could not find obvious relations between these parameters.Цель: изучить свойства лейкозных клеток детей больных ОЛЛ с положительным и отрицательным результатом мониторинга минимальной резидуальной болезни после индукционной терапии. Методы: согласно результатам мониторинга минимальной резидуальной болезни (MRD) с помощью трехцветной проточной цитометрии на 36-й день больные были разделены на 2 группы: MRD– и MRD+. Для изучения уровней экспрессии генов MDR1, LRP, BCRP и BCL-2 в образцах костного мозга пациентов с диагнозом первичного ОЛЛ использовался метод относительной количественной ПЦР в режиме реального времени. Результаты: медианы уровней экспрессии гена MDR1 в изученных группах пациентов отличались незначительно и составили 22,8 (0,02–26,6; n = 9) в MRD+ и 24,8 (3,9–41,4; n = 10) в MRD–-группе. Тенденция к повышенной экспрессии гена BCL-2 выявлена в группе MRD+, где медиана составила 5992,9 (521,0–10362,0; n = 9), по сравнению с 3183,6 (1947,9–6581,0; n = 10) в группе MRD–. Относительная экспрессия гена LRP в изучаемых группах оказалась сходной, медианы составили 1934,9 (1500,7–3490,4; n = 9) и 1408,5 (665,5–2917,1; n = 10) в MRD+- и MRD–-группах соответственно. Медиана уровня экспрессии гена BCRP в группе MRD+ была значительно ниже таковой в группе MRD– — 76000,0 (48196,2–169230,8; n = 9) и 227967,2 (16683,7–422222,2; n = 10) соответственно, однако статистических анализ не подтвердил значимость различий. Выводы: при изучении уровней экспрессии генов MDR1, LRP, BCRP и BCL-2 в лейкозных клетках при установлении первичного диагноза ОЛЛ у детей и при мониторинге MRD после индукционной терапии не выявлена связь между данными параметрами