156 research outputs found
All-fiber optical supercontinuum sources in 1.7-3.2 μm range
We report supercontinuum generation in the 1.7-2.9 μm range with up to 3.08 W of output power and in the range of 1.93-3.18 μm with up to 3.8 W of output power from all-fiber MOPA pulsed systems with Tm-doped fiber mode-locked seed laser. Supercontinuum generation was demonstrated in nonlinear germanate fibers and fluoride (ZBLAN) fibers. The supercontinuum bandwidth reached 1250 nm at -10 dB level
Promising Breeding Material from Triticum Turgidum L.
Turgid wheat is distinguished by a large multi-grain ear. Therefore, the involvement of its varieties in the selection process to increase the productivity of winter durum wheat is very promising. This paper shows the results of creating a highly productive source material to improve the production capabilities of existing varieties of winter hard and turgid wheat. To do this, a cross was performed between a loose-leaved multi-grain variety var.martensii with a large-seeded and dense-leaved var.salomonis. By weight of the grain from the ear, the resulting hybrids significantly exceeded the original parent forms and the zoned varieties of winter hard and turgid wheat, cultivated simultaneously with them, but they were taller. When a hybrid was crossed with a modern low-growing variety of Terra, more productive forms were produced relative to the zoned varieties and the same short-stem forms, which can be used as a promising source of breeding material. The selected hybrids, both individually and on average, clearly outperformed the zoned varieties of durum and turgid wheat in terms of grain weight per ear. The production characteristics of the ear on average for the hybrid were as follows: the length of the ear was 7.6 cm, and 18.9 spikelets and 57.5 grains were formed.
Keywords: Triticum turgidum, varieties, hybrid forms, productivity, source material, zoned varietie
Is Protein Folding a Thermodynamically Unfavorable, Active, Energy-Dependent Process?
The prevailing current view of protein folding is the thermodynamic hypothesis, under which the native folded conformation of a protein corresponds to the global minimum of Gibbs free energy G. We question this concept and show that the empirical evidence behind the thermodynamic hypothesis of folding is far from strong. Furthermore, physical theory-based approaches to the prediction of protein folds and their folding pathways so far have invariably failed except for some very small proteins, despite decades of intensive theory development and the enormous increase of computer power. The recent spectacular successes in protein structure prediction owe to evolutionary modeling of amino acid sequence substitutions enhanced by deep learning methods, but even these breakthroughs provide no information on the protein folding mechanisms and pathways. We discuss an alternative view of protein folding, under which the native state of most proteins does not occupy the global free energy minimum, but rather, a local minimum on a fluctuating free energy landscape. We further argue that ΔG of folding is likely to be positive for the majority of proteins, which therefore fold into their native conformations only through interactions with the energy-dependent molecular machinery of living cells, in particular, the translation system and chaperones. Accordingly, protein folding should be modeled as it occurs in vivo, that is, as a non-equilibrium, active, energy-dependent process
Влияние материнской инфекции на морфо-функциональное состояние коры надпочечников недоношенных плодов
Adrenals as the one of main organs that reacts to a stress have the extreme importance for the normal organism development. Despite numerous researches in the perinatal period, the problem of pregnancy infections on the morpho-functional state of adrenals of fetuses was not completely studied.Methods. Organs were taken from incisions of premature fetuses (gestational age 24-36 weeks). The material was divided in 3 groups: control, chronic intrauterine hypoxia and infections. The study included two adrenals, investigated histologically and immunohistochemically.Results. Mother’s infectious pathology has the more harmful effect on fetuses’ adrenals than a “pure chronic intrauterine hypoxia”. Іn fetuses was reveled a hypoplasia of glomerular zone. In all groups were observed nidi of cytolysis and spongyocytes resorption in the bundle zone with cortisol production increase. In a fetal cortex is observed the exhaustion of its functional activity.Conclusions. These data testify to adaptive reactions of fetuses’ adrenals as a response to antigen stimulationУстановлено, что многие заболевания, возникшие в разные периоды онтогенеза, являются результатом нарушений, происходящих во внутриутробном периоде. Надпочечники, как один из главных органов, активно реагирующих на стресс, крайне важны для нормального развития организма. Несмотря на многочисленные исследования в перинатальном периоде, проблема влияния инфекции беременной на морфо-функциональное состояние надпочечных желез плода практически не изучен
YDFL operating in 1150-1200-nm spectral domain
A family of high-power Yb-doped fiber lasers operated in the range of 1150-1180 nm with output powers of up to 35 W and optical efficiencies up to 60% is realized. Operation at 1200 nm is also demonstrated. Amplified spontaneous emission increase with output power increase is analyzed in frames of the inhomogeneous broadening concept
Dissipative Soliton Resonance: Adiabatic Theory and Thermodynamics
We present the adiabatic theory of dissipative solitons (DS) of complex
cubic-quintic nonlinear Ginzburg-Landau equation (CQGLE). Solutions in the
closed analytical form in the spectral domain have the shape of Rayleigh-Jeans
distribution for a purely real quintic nonlinearity. The DS parametric space
forms a two-dimensional (or three-dimensional for the complex quintic
nonlinearity) master diagram connecting the DS energy and a universal parameter
formed by the ratio of four real and imaginary coefficients for dissipative and
non-dissipative terms in CQGLE. The concept of dissipative soliton resonance
(DSR) is formulated in terms of the master diagram, and the main signatures of
transition to DSR are demonstrated and experimentally verified. We show a close
analogy between DS and incoherent (semicoherent) solitons with an ensemble of
quasi-particles confined by a collective potential. It allows applying the
thermodynamical approach to DS and deriving the conditions for the DS energy
scalability.Comment: 31 pages, 15 figure
Investigating Massive Multilingual Pre-Trained Machine Translation Models for Clinical Domain via Transfer Learning
Massively multilingual pre-trained language models (MMPLMs) are developed in
recent years demonstrating superpowers and the pre-knowledge they acquire for
downstream tasks. This work investigates whether MMPLMs can be applied to
clinical domain machine translation (MT) towards entirely unseen languages via
transfer learning. We carry out an experimental investigation using Meta-AI's
MMPLMs ``wmt21-dense-24-wide-en-X and X-en (WMT21fb)'' which were pre-trained
on 7 language pairs and 14 translation directions including English to Czech,
German, Hausa, Icelandic, Japanese, Russian, and Chinese, and the opposite
direction. We fine-tune these MMPLMs towards English-\textit{Spanish} language
pair which \textit{did not exist at all} in their original pre-trained corpora
both implicitly and explicitly. We prepare carefully aligned \textit{clinical}
domain data for this fine-tuning, which is different from their original mixed
domain knowledge. Our experimental result shows that the fine-tuning is very
successful using just 250k well-aligned in-domain EN-ES segments for three
sub-task translation testings: clinical cases, clinical terms, and ontology
concepts. It achieves very close evaluation scores to another MMPLM NLLB from
Meta-AI, which included Spanish as a high-resource setting in the pre-training.
To the best of our knowledge, this is the first work on using MMPLMs towards
\textit{clinical domain transfer-learning NMT} successfully for totally unseen
languages during pre-training.Comment: Accepted to ClinicalNLP-2023 WS@ACL-202
Flat-top supercontinuum and tunable femtosecond fiber laser sources at 1.9-2.5 μm
We report the high-energy flat-top supercontinuum covering the mid-infrared wavelength range of 1.9-2.5 μm as well as electronically tunable femtosecond pulses between 1.98-2.22 μm directly from the thulium-doped fiber laser amplifier. Comparison of experimental results with numerical simulations confirms that both sources employ the same nonlinear optical mechanism - Raman soliton frequency shift occurring inside the Tm-fiber amplifier. To illustrate that, we investigate two versions of the compact diode-pumped SESAM mode-locked femtosecond thulium-doped all-silica-fiber-based laser system providing either broadband supercontinuum or tunable Raman soliton output, depending on the parameters of the system. The first system operates in the Raman soliton regime providing femtosecond pulses tunable between 1.98-2.22 μm. Wide and continuous spectral tunability over 240 nm was realized by changing only the amplifier pump diode current. The second system generates high-energy supercontinuum with the superior spectral flatness of better than 1 dB covering the wavelength range of 1.9-2.5 μm, with the total output energy as high as 0.284 μJ, the average power of 2.1 W at 7.5 MHz repetition rate. We simulate the amplifier operation in the Raman soliton self-frequency shift regime and discuss the role of induced Raman scattering in supercontinuum formation inside the fiber amplifier. We compare this system with a more traditional 1.85-2.53 μm supercontinuum source in the external highly-nonlinear commercial chalcogenide fiber using the Raman soliton MOPA as an excitation source. The reported systems1 can be readily applied to a number of industrial applications in the mid-IR, including sensing, stand-off detection, medical surgery and fine material processing
A route to high peak power and energy scaling in the mid-IR chirped-pulse oscillator-amplifier laser systems
The paper introduces a new route towards the ultrafast high laser peak power
and energy scaling in a hybrid mid-IR chirped pulse oscillator-amplifier
(CPO-CPA) system, without sacrificing neither the pulse duration nor energy.
The method is based on using a CPO as a seed source allowing the beneficial
implementation of a dissipative soliton (DS) energy scaling approach, coupled
with a universal CPA technique. The key is avoiding a destructive nonlinearity
in the final stages of an amplifier and compressor elements by using a chirped
high-fidelity pulse from CPO. Our main intention is to realize this approach in
a Cr2+:ZnS-based CPO as a source of energy-scalable DSs with well-controllable
phase characteristics for a single-pass Cr2+:ZnS amplifier. A qualitative
comparison of experimental and theoretical results provides a road map for the
development and energy scaling of the hybrid CPO-CPA laser systems, without
compromising pulse duration. The suggested technique opens up a route towards
extremely intense ultra-short pulses and frequency combs from the multi-pass
CPO-CPA laser systems that are particularly interesting for real-life
applications in the mid-IR spectral range from 1 to 20 um.Comment: 16 pages, 14 figure
A Mammalian Homolog of Drosophila melanogaster Transcriptional Coactivator Intersex Is a Subunit of the Mammalian Mediator Complex
The multiprotein Mediator complex is a coactivator required for transcriptional activation of RNA polymerase II transcribed genes by DNA binding transcription factors. We previously partially purified a Med8-containing Mediator complex from rat liver nuclei (Brower, C. S., Sato, S., Tomomori-Sato, C., Kamura, T., Pause, A., Stearman, R., Klausner, R. D., Malik, S., Lane, W. S., Sorokina, I., Roeder, R. G., Conaway, J. W., and Conaway, R. C. (2002) Proc. Natl. Acad. Sci. U. S. A. 99, 10353–10358). Analysis of proteins present in the most highly enriched Mediator fractions by tandem mass spectrometry led to the identification of several new mammalian Mediator subunits, as well as several potential Mediator subunits. Here we identify one of these proteins, encoded by the previously uncharacterized AK000411 open reading frame, as a new subunit of the mammalian Mediator complex. The AK000411 protein, which we designate hIntersex (human Intersex), shares significant sequence similarity with the Drosophila melanogaster intersex protein, which has functional properties expected of a transcriptional coactivator specific for the Drosophila doublesex transactivator. In addition, we show that hIntersex assembles into a subcomplex with Mediator subunits p28b and TRFP. Taken together, our findings identify a new subunit of the mammalian Mediator and shed new light on the architecture of the mammalian Mediator complex
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