Quantum Induced Coherence Light Detection and Ranging.

Quantum illumination has been proposed and demonstrated to improve the signal-to-noise ratio (SNR) in light detection and ranging (LiDAR). When relying on coincidence detection alone, such a quantum LiDAR is limited by the timing jitter of the detector and suffers from jamming noise. Inspired by the Zou-Wang-Mandel experiment, we design, construct, and validate a quantum induced coherence (QuIC) LiDAR which is inherently immune to ambient and jamming noises. In traditional LiDAR the direct detection of the reflected probe photons suffers from deteriorating SNR for increasing background noise. In QuIC LiDAR we circumvent this obstacle by only detecting the entangled reference photons, whose single-photon interference fringes are used to obtain the distance of the object, while the reflected probe photons are used to erase path information of the reference photons. In consequence, the noise accompanying the reflected probe light has no effect on the detected signal. We demonstrate such noise resilience with both LED and laser light to mimic the background and jamming noise. The proposed method paves a new way of battling noise in precise quantum electromagnetic sensing and ranging.

[Sarcopenia as the reason of hypodiagnostics of chronic kidney disease in patients with chronic heart failure.]

The purpose of the research is comparison of glomerular filtration rate calculated on the basis of serum concentrations of creatinine and cystatin C in patients with chronic heart failure and sarcopenia. In this research 86 patients with chronic heart failure and sarcopenia aged 60 to 92 years (mean age 75±7 years) were examined. GFR calculation was determined using formulas based on creatinine (CKD-EPIC), cystatin C (CKD-EPICys) in blood and both markers (CKD-EPICr-Cys). The concentration of cystatin C in blood serum was determined by the immunoturbidimetric method, and creatinine by the Jaffe kinetic method. Composite body composition was studied in all patients using dual-energy X-ray absorptiometry with calculation of the sarcopenia index (according to FNIH criteria, 2014) and measurement of total fat mass. A test with a 6-minute walk, an assessment according to the SHOKS scale (clinical condition assessment scale for CHF), transthoracic echocardiography with the measurement of EDD, ESD, LVEF, LVМ, LVIM, indicators of LV diastolic function was performed. Depending on the diagnostic criteria for sarcopenia, patients were divided into 2 groups: the first - a combination of heart failure and sarcopenia; the second - CHF without sarcopenia. In patients with CHF and sarcopenia, GFR was reassessed as calculated by the creatinine level by 23% (the absolute difference is more than 18 ml/min/1,73 m2) compared with GFR estimated by the level of cystatin C. In patients with heart failure and sarcopenia, when using a serum concentration of creatinine, there is a hypodiagnostics of the severity of chronic kidney disease. In this regard, if there are signs of sarcopenia, it is recommended to use the formula CKD-EPICys to calculate GFR.

[Optimization of the invasive strategy for acute coronary syndrome in patients of the older age group.]

A study is presented on the effectiveness and safety of various anticoagulants used in patients of an older age group with acute coronary syndrome during percutaneous coronary interventions. Bivalirudin was shown to be highly effective in comparison with unfractionated heparin and monafram in relation to the amount of bleeding that occurs in the postoperative period and adverse cardiovascular complications.

[Comparative evaluation of scales for the assessment of senile asthenia syndrome in patients with acute coronary syndrome.]

The syndrome of senile asthenia (frailty) in patients with acute coronary syndrome is recognized as one of the risk factors for the development of adverse outcomes after undergoing cardiosurgical interventions, and the search for an optimal method for assessing this syndrome could be a screening to identify patients at increased risk. This study compares two methods for assessing senile asthenia syndrome in patients with acute coronary syndrome, its prevalence in this category of patients, its relationship with clinical characteristics and 1-year mortality after hospitalization. According to the results of the study, senile asthenia syndrome was observed more often in the group of patients older than 75 years. Patients with senile asthenia assessment using the Green scale had a higher risk on the GRACE scale and the presence of this syndrome was an independent 1-year mortality predictor after hospitalization.

Quantum photonic transistor controlled by an atom in a Floquet cavity-QED system.

The photon transmission of a Floquet cavity quantum electrodynamic (QED) system containing three periodically modulated cavities interacting with a two-level atom is investigated. The input-output relations and the second-order correlation functions of the output fields are calculated. The system demonstrates the feature of a quantum photonic transistor, i.e., the photon transmission is controlled by the quantum states of the atom. This device can be used as a building block for various quantum information processing.

[Features of changes in volume-impedance hemodynamic indicators during the tilt test in young males with a history of vasovagal syncopes].

BACKGROUND: The direction of changes in hemodynamic parameters during the tilt test (TT) nin individuals with history of vasovagal syncope (VVS) is a subject of discussion. OBJECTIVE: to study changes of volume-impedance hemodynamic indicators in the process of tilt test in somatically healthy young men with history of VVS. MATERIALS AND METHODS: A total of 102 men aged 18-30 years were divided into 4 groups, taking into account the specific features of fainting history and response to TT. Persons of group 1 (n=14) had history of VVS and positive response to TT (syncope). Subjects of group 2 (n=14) had history of VVS and a pattern of postural tachycardia without fainting during TT. Persons of group 3 (n=42) had history of VVS and negative response to TT. Subjects of group 4 (n=32) had no history of VVS and negative response to TT. During TT, we studied dynamics of some indicators, including cardiac output (CO) and total peripheral vascular resistance (TPVR). RESULTS: In individuals of all groups in the initial horizontal phase of TT values of CO and TPVR corresponded to the norm. Subjects of group 1 had significantly lower CO compared with subjects of groups 2, 3, 4 (p<0.05, p<0.01, p<0.05, respectively). Values of TPVR in subjects of group 1 were significantly higher than in subjects of groups 2, 3, 4 (p<0.05; p<0.05; p<0.05, respectively). In response to orthostasis CO values increased in groups 1, 2, 4 (by 18%, 10%, 5%, respectively) and did not change in group 3; TPVR values decreased in groups 1, 2 (by 8%, 0.5%, respectively), and increased in groups 3, 4 (by 8%, 4% respectively). In the final horizontal phase of TT, CO values in group 1 were significantly lower than in groups 3, 4 (p<0.05), while TPVR values did not significantly differ between all groups (p>0.05). CONCLUSIONS: In tilt-positive and tilt-negative subjects with history of VVS, standardized postural stress leads to unidirectional changes in cardiac output, but to multidirectional changes in total peripheral vascular resistance.

[The development of chronic heart failure in elderly patients with low ejection fraction at baseline in the acute phase of myocardial infarction].

There was performed analysis according to 5-year follow incidence of heart failure in patients with acute myocardial infarction (AMI) with low ejection fraction in A; the characteristics of chronic heart failure (CHF) in elderly and senile were determined; the value of a number of clinical and morphological parameters for prediction of CHF were studied. The study included 135 patients of Intensive Care Unit with a diagnosis AMI showing according to the initial echocardiography reduced ejection fraction in the first 24-48 hours. In the course of monitoring patients, routine methods of clinical examination were used, the main quantitative technique was echocardiography, qualitative indicators were assessed including by collecting anamnesis and filling out questionnaires for heart failure, and then standard statistical methods were used. In the process of observation it was found that patients with acute myocardial infarction in acute elderly age worsens the prognosis of heart failure and mortality forecast, low ejection fraction in the acute period is a negative predictor of heart failure in all age groups, but more pronounced in the elderly. Development and growth of CHF after AMI occurs, despite the growth of ejection fraction (EF) in both age groups. CHF dynamics depends on the systolic and diastolic dysfunction. In the older age group plays a decisive role systolic dysfunction.

Time-resolved Assessment of Drying Plants by Brillouin and Raman Spectroscopies.

Raman and Brillouin spectroscopy enable non-invasive assessment of chemical and elastic properties of biomaterials, respectively. In this report, Brillouin micro-spectroscopy was used for the time-resolved analysis of elastic properties of Populus and Geranium leaves, while Raman micro-spectroscopy was employed for the assessment of their chemical variation during drying. Spectroscopic assessment of elastic and chemical properties can improve our understanding of mechano-chemical changes of plants in response to environmental stress and pathogens at the microscopic cellular level. This report demonstrates the potential of multimodal optical sensing and imaging of plants as an emerging technique for the quantitative assessment of agricultural crops.

Amplitude concentration in a phase-modulated spectrum due to femtosecond filamentation.

We present a method by which the spectral intensity of an ultrafast laser pulse can be accumulated at selected frequencies by a controllable amount. Using a 4-f pulse shaper we modulate the phase of the frequency components of a femtosecond laser. By inducing femtosecond filamentation with the modulated pulse, we can concentrate the spectral amplitude of the pulse at various frequencies. The phase mask applied by the pulse shaper determines the frequencies for which accumulation occurs, as well as the intensity of the spectral concentration. This technique provides a way to obtain pulses with adjustable amplitude using only phase modulation and the nonlinear response of a medium. This provides a means whereby information which is encoded into spectral phase jumps may be decoded into measurable spectral intensity spikes.

Optimization of focusing through scattering media using the continuous sequential algorithm.

The ability to control the propagation of light through scattering media is essential for atmospheric optics, astronomy, biomedical imaging and remote sensing. The optimization of focusing light through a scattering medium is of particular interest for the case of highly scattering materials. Optical wavefront beam-shaping plays a critical role in optimizing such a propagation; however, an enormous field of adjustable parameters makes the overall task complicated. Here, we propose and experimentally evaluate several variations on the standard continuous sequential algorithm that hold a promise of revealing new, faster and more efficient optimization algorithms for selecting an optical wavefront to focus light through a scattering medium. We demonstrate that the order in which pixels are chosen in the continuous sequential algorithm can lead to a 2-fold decrease in the number of iterations required to reach a given enhancement.

Effect of pulse shape on the efficiency of multiphoton processes: implications for biological microscopy.

The effects of spectral shape on two photon fluorescence excitation are investigated experimentally using an acousto-optic pulse shaper to modify femtosecond pulses from a Ti:sapphire laser. By using different spectral window shapes, we find that the measured two photon efficiency can vary by a factor of 2 for differently shaped spectra with the same full width at half maximum. We find that these effects are described well by a simple model assuming transform-limited pulses. The fact that even small changes in the spectral wings can significantly affect the efficiency of nonlinear processes has implications for biological multiphoton imaging, where it may be desirable to minimize sample exposure to radiation and maximize fluorescence or harmonic efficiency. © 1999 Society of Photo-Optical Instrumentation Engineers.

Spatial organization of subfields in receptive fields of cells in cat striate cortex.

Spatial organization of receptive fields (RF) of cells in cat striate cortex was investigated with moving and flashing light and dark bars and with grating-patterns of a varying number of cycles. It was shown that the maximum number of subfields in a simple cell is equal to eight or the number of periods in weighting function is equal to four. Quantitative comparison of the data with the results of seven other studies allows us to suggest that the number of periods in linear component of some complex cells is close to this value. The discrepancies between the results of different authors in estimation of the number of subfields are explained by the experimental data.

Efficiency optimization for systems and components in microwave power engineering.

The paper is concerned with one aspect of optimization of microwave thermal processing, namely, with optimization of energy coupling interpreted as a numerical characteristic of system efficiency. Since in computer-aided design coupling can be evaluated through the computed reflections, an optimization scheme is presented that is particularly suitable for minimizing the reflection coefficient in typical systems and elements of microwave power engineering. Based on response surface methodology and the sequential quadratic programming for constrained optimization, the procedure is linked with the full-wave 3-D FDTD electromagnetic simulator QuickWave-3D. Credibility and effectiveness of the method is illustrated by four examples: dimensional optimization is performed for a dry waveguide load, a waveguide T-junction with a partial-height post, a water cylinder in a cavity, and a slotted waveguide-backed radiating element.

Coherent anti-Stokes Raman scattering in silicon nanowire ensembles.

In this letter, we, for the first time, report on coherent anti-Stokes Raman scattering (CARS) spectroscopy of an ensemble of silicon nanowires (SiNWs) formed by wet chemical etching of crystalline silicon with a mask of silver nanoparticles. The fabricated SiNWs have diameter ranged from 30 to 200 nm and demonstrate both visible and infrared photolumine cence (PL) and spontaneous Raman signal, with their intensities depending on presence of silver nanoparticles in SiNWs. The efficiency of CARS in SiNW ensembles is found to be significantly higher than that in crystalline silicon. The results of CARS and PL measurements are explained in terms of resonant excitation of the electron states attributed to silicon nanoparticles.

SPECTROSCOPY/MICROSCOPY: Nonlinear Raman microscopy eyes clinical application.

Nonlinear Raman microscopy is an emerging technique in biomedical imaging. An inexpensive prototype system, based on coherent anti-Stokes Raman scattering (CARS), demonstrates value for real-time, minimally invasive chemical analysis of cells and tissues. It overcomes drawbacks of both Raman and CARS, and in doing so demonstrates potential for clinical application-including blood analysis and breast cancer detection.

Broadly tunable 30-fs pulses produced by optical parametric amplification.

Broadly tunable 30-fs pulses have been generated by parametric amplification of a white-light continuum at kilohertz repetition rates.

High-energy self-starting femtosecond Cr(4+):Mg(2)SiO(4) oscillator operating at a low repetition rate.

We describe a self-starting high-power femtosecond laser based on the Cr(4+):Mg(2)SiO(4) crystal that produces 17-nJ pulses of 40-fs duration at 26.5-MHz repetition rate. This low repetition rate is achieved by employment of a one-to-one telescope in the cavity. The pulse energy is five times greater than with a short-resonator laser. To our knowledge, the laser produces the highest energy ever achieved from this type of laser directly from the resonator without cavity dumping or external amplification. We believe that this laser source can be used for many applications, including nonlinear optics, microscopic imaging, and micromachining of silicon and other semiconductor materials.

Harmonic basis functions for spatial coding in the cat striate cortex.

The number of subregions in the activity profiles of simple cells varies in different cells from 2-8; that is, the number of cycles in the weighting function varies from 1-4. The distribution of receptive-field (RF) sizes at eccentricities of 0-6 deg are clustered at half-octave intervals and form a discrete distribution with maxima at 0.62, 0.9, 1.24, 1.8, 2.48, and 3.4 deg. The spatial frequencies to which the cells are tuned are also clustered at half-octave intervals, forming a discrete distribution peaking at 0.45, 0.69, 0.9, 1.35, 1.88, 2.7, 3.8, and 5.6 cycles/deg. If we divide the RF sizes by the size of the period of the subregions, then the average indices of complexity (really existing) or the number of cycles in the weighting function form (after normalization) the sequences: 1, 1.41, 2.0, 2.9, 4.15. The relation between the bandwidth of the spatial-frequency characteristic and the optimal spatial frequency is in accordance with predictions of the Fourier hypothesis. The absolute bandwidth does not change with the number of cycles/module. This means that inside the module the absolute bandwidth does not change with the number of the harmonic. The results allow us to suggest the following. A module of the striate cortex, which is a group of cells with RFs of equal size projected onto the same area of central visual field, accounts for the Fourier description of the image. The basis functions of the module are composed of four harmonics only, irrespective of size and position of the module. Besides linear cells (sinusoidal and cosinusoidal elements), the module contains nonlinear cells, performing a nonlinear summation of the responses of sinusoidal and cosinusoidal elements. Such cells are characterized by an index of complexity which is more than the number of cycles in the weighting function and by marked overlap of ON and OFF zones. The analysis of organization suggests that the cells can measure the amplitude and phase of the stimulus.

Nonlinear optical microscopy analysis of ultrafast phase transformation in vanadium dioxide.

The nonlinear optical properties of solid-solid phase transformation in vanadium dioxide are studied. It is found that the efficiency of the third-harmonic optical signal generated from the surface of the material increases by 1.5 orders of magnitude as a function of this phase transformation. Microscopy studies show the hysteresis of the phase transformation on a micrometer-size scale.

Quantitative characterization of aqueous solutions probed by the third-harmonic generation microscopy.

Third-harmonic microscopy is one of the emerging techniques for noninvasive microscopic imaging of biological structures. We use a novel technique for nonlinear optical material characterization and study the effect of different environment and the structural sensitivity of the third harmonic. In particular, a transformation of collagen in solution is observed for the first time using third-harmonic generation. We also study the ultimate limits of the third harmonic to detect micro- and nanoscopic features inside living cells and find that structures as small as 50 nm can be detected using the current level of technology.