Controllable direction of liquid jets generated by thermocavitation within a droplet.

A high-velocity fluid stream ejected from an orifice or nozzle is a common mechanism to produce liquid jets in inkjet printers or to produce sprays among other applications. In the present research, we show the generation of liquid jets of controllable direction produced within a sessile water droplet by thermocavitation. The jets are driven by an acoustic shock wave emitted by the collapse of a hemispherical vapor bubble at the liquid-solid/substrate interface. The generated shock wave is reflected at the liquid-air interface due to acoustic impedance mismatch generating multiple reflections inside the droplet. During each reflection, a force is exerted on the interface driving the jets. Depending on the position of the generation of the bubble within the droplet, the mechanical energy of the shock wave is focused on different regions at the liquid-air interface, ejecting cylindrical liquid jets at different angles. The ejected jet angle dependence is explained by a simple ray tracing model of the propagation of the acoustic shock wave inside the droplet.

Raman-induced polarization stabilization of vector solitons in circularly birefringent fibers.

Vector soliton propagation in circularly birefringent fibers was studied by perturbation analysis and numerically. The results show that in presence of both Raman self-frequency shift and group velocity difference between circularly polarized components the Raman cross-polarization term causes an energy transfer from the slower to the faster circular component of vector solitons. This effect leads to polarization stabilization of circularly polarized vector solitons.

Time-resolved analysis of cavitation induced by CW lasers in absorbing liquids.

We present novel results on thermocavitation using a CW medium-power near infrared laser (lambda=975 nm) focused into a saturated copper nitrate saline solution. Due to the large absorption coefficient at the laser wavelength, the solution can be heated to its superheat limit (T(sh) approximately 270-300 degrees C). Superheated water undergoes explosive phase transition around T(sh) producing approximately half-hemispheric bubbles (gamma approximately 0.5) in close contact with the substrate. We report the temporal dynamic of the cavitation bubble, which is much shorter than previously reported under similar conditions. It was found that the bubble radius and pressure wave amplitude emitted on bubble collapse decreases exponentially with the power laser. Thermocavitation can be a useful tool for the generation of ultrasonic waves and controlled ablation for use in high-resolution lithography.

Perturbation series for calculation of invariant surface splitting in volume-preserving maps.

The invariant surface splittings for small perturbation are described for two-dimensional and three-dimensional sample volume-preserving maps by explicit analytic expressions obtained from perturbation series for the self-adjoint operator related to the Frobenius-Perron operator.

[Comparison of transthoracic, transesophageal, and intracardiac echocardiography sensitivity for guiding transseptal puncture during radiofrequency ablation in the left atrium].

The paper contains comparison of sensitivity and rates of false negative results of transthoracic (TT), transesophageal (TE), and intracardiac (IC) echocardiography (echoCG) during transseptal puncture in the run of the procedure of radiofrequency ablation of atrial fibrillation. In the work fulfilled we analyzed results of 208 echocardiographical intraprocedural investigations conducted with the aim of visualization of interatrial septum (IAS) during transseptal puncture. TT, TE and IC echoCG were carried out in 32, 26, and 150 cases, respectively. Phenomenon of IAS stretching was visualized by TT echoCG in 2 (6%) cases (sensitivity 6.7%). At TE tenting phenomenon was verified in 20 patients (20%) (sensitivity 86.9%). Puncture of IAS was carried out under IC echoCG control in 127 patients. Puncture was made in the center of thin portion of IAS (in the region of fossa ovalis), in its upper and lower portions in 65, 28, and 15.7% of cases, respectively. Sensitivity of IC echoCG was 98.4%. Rate of false positive results reached 92.8, 13.04 and 1.5% for TT, TE and IC echoCG, respectively. At present IC echoCG is most sensitive and safe ultrasound technique for verification of optimal positioning of the system for conduct of transseptal puncture in the region of IAS in comparison with TT and TE echoCG.

Initial development of supercontinuum in fibers with anomalous dispersion pumped by nanosecond-long pulses.

We propose and compare with experimental data a two-stage model of supercontinuum formation in a fiber for nanosecond-long pulse with intensities in 10 W range. As a result of the first stage, the sea of solitons is formed. The second stage is spectrum modification because of Raman interaction.

[The experience of the use of intracardiac echocardiography during puncture of atrial septum].

We analyzed results of 175 intracardiac ultrasound studies (ICUS) in 113 men (mean age 54,6 +/- 11,0 years) and 62 women (mean age 49,7 +/- 8,9 years) with atrial fibrillation (n=146) and WPW syndrome (n=29). ICUS was used for guidance of catheters or electrodes from right to left atrium through atrial septum in 160 procedures of radiofrequency ablations for atrial fibrillation (n=146) or WPW syndrome (n=14). Complications of transseptal puncture developed in 4 patients (2,7%) with atrial fibrillation. There were no procedure related deaths. In all cases ICUS allowed to visualize interatrial septum and its thinnest part. Thus ICUS facilitates transseptal approach to the left atrium, provides lowering of risk of dangerous complications, and allows real time monitoring of possible intraprocedural complications.

Analytical solutions for three and four diffraction orders interaction in Kerr media.

The analytical solution for the interaction of three diffraction orders in the Kerr medium is obtained by reducing the problem to the completely integrable Hamiltonian task. Intensities of all waves are periodic with propagation length and linearly related, the amplitudes are quasi-periodic and expressed in elliptic functions. Symmetrical four-order interaction also admits an analytical solution.

Spectral limits for periodic pattern propagation in Kerr media.

We consider the propagation of periodic waves with initially narrow spatial spectra in a Kerr medium. The set of constants of motion closely related to the order amplitudes is introduced. It is shown that the spatial spectrum remains uniformly narrow with propagation for both self-focusing and self-defocusing nonlinearity. In addition, for sufficiently weak nonlinearity, initially strong orders always remain strong. Thus the problem is shown to be essentially finite dimensional and well approximated by a proper set of coupled ordinary differential equations.

Propagation dynamics of weakly localized cnoidal waves in dispersion-managed fiber: from stability to chaos.

We study the dynamics of propagation of the pulse train modeled by truncated cnoidal-type wave in a nonlinear dispersion-managed (DM) fiber. Computer simulations permit to select fiber parameters and waveform to ensure self-repeating of wave after the dispersion map period. It is shown that the long-period maps lead to the complicated chaotic behavior of cnoidal type wave, namely the Kolmogorov-Arnold-Moser (KAM) chaos.

[Value of 2-dimensional echocardiography in the diagnosis of pericardial effusion]. / Znachenie dvukhmernoi ékhokardiografii v diagnostike perikardial'nogo vypota.

Characteristic echocardiographic signs of pericardial exudate were established on the basis of M-scanning and sectoral echocardiography in 44 patients with exudate in the pericardial cavity. It was noted that a two-dimensional examination was more effective in identifying and locating small pericardial exudate in cases of a considerable amount of fluid in the pericardial cavity. The role of two-dimensional examination in the differential diagnosis of pericardial exudate was outlined. The drawbacks of sectoral scanning were also described.

[Importance of ultrasonic studies in diagnosing and assessing heart function in aortic coarctation in adults]. / Znachenie ul'trazvukovogo issledovaniia v diagnostike i otsenke sostoianiia serdtsa pri koarktatsii aorty u vzroslykh.

Aortic coarctation was diagnosed with the aid of sectorial scanning from the suprasternal position in 6 of 7 patients. Ultrasonic investigation allows one to assess myocardial status and detect a prolapse of the atrioventricular valves, aortal valve protrusion, the presence of a bicuspid aortal valve and other abnormalities accompanying aortic coarctation in adult patients.

[Features of the course and evaluation of the efficacy of surgical treatment of adhesive pericarditis with constriction]. / Osobennosti techeniia i otsenki éffektivnosti operativnogo lecheniia adgezivnykh perikarditov s konstriktsiei.

Two groups of patients with constrictive pericarditis were identified on the basis of clinical and instrumental examination including echocardiography and computerized tomography of the heart: patients with complete obliteration of the pericardial sac and constriction, and those with exudative/adhesive pericarditis and constriction. Part of the patients were subjected to subtotal pericardectomy. An improvement of left-ventricular diastolic function and hemodynamic parameters was demonstrated 1 to 1.5 months after the operation. Postoperative echocardiography showed persistent disorders of interventricular septum movement and multilayer abnormal echoes in the left-ventricular posterior wall area.

[Prolonged cardioselective blockade of beta-1 adrenoreceptors in combination with increased diuresis as a method of choice in the treatment of hypertension]. / Prolongirovannaia kardioselektivnaia blokada beta-1-adrenoretseptorov v kombinatsii s usilennym diurezom kak metod vybora v lechenii gipertonicheskoi bolezni.

The clinical effects of Tenoric, a long-acting combined drug (atenolol and chlorthalidone in a tablet), were studied in 31 patients with Stages I and II hypertensive disease, by using echocardiography, daily automatic blood pressure monitoring, bicycle ergometry, measurements of plasma renin and aldosterone. The drug was found to be highly clinically effective in labile and sustained hypertension. When given once or twice a day, it makes it possible to reliably monitor blood pressure, improve hemodynamic parameters, as reflected by lower cardiac output and decreased peripheral vascular resistance, reduce the estimated mass of the left myocardium, alleviate a pressor response to exercise and enhance its tolerance, lower plasma renin levels. The side effects of the drug are minimal and include moderate bradycardia. Peripheral vasospasm and systemic weakness were observed in single cases. There were no atherogenic changes in lipid spectrum and disturbed glucose and uric acid metabolism during the drug therapy.

[The mechanisms of the development and diagnosis of myocardial infarct in septic endocarditis]. / Mekhanizmy razvitiia i diagnostika infarkta miokarda pri septicheskom éndokardite.

Based on the clinical, instrumental and biochemical findings, out of 104 patients with septic endocarditis 11 (10.6%) were diagnosed to have myocardial infarction. It was provoked by coronary artery embolism, the covering of the coronary artery ostium by vegetation from the aortal cusp, a decrease of perfusion pressure in atherosclerosis stenosed coronary arteries because of marked insufficiency of the aortal cusp. In more than half the cases, the clinical picture of myocardial infarction was atypical, painless. Echocardiographic demonstration of the vegetations near the coronary artery ostium permits forecasting the possibility of its covering with vegetation, the threat of the occurrence of acute coronary insufficiency, which may appear an additional indication for heart valve replacement.

[Differential echocardiographic diagnosis of a giant left atrium and pericardial effusion]. / Differentsial'naia ékhokardiograficheskaia diagnostika gigantskogo levogo predserdiia i perikardial'nogo vypota.

With a sharp increase in the sizes of the left atrium its wall in the form of a fold can be seen behind the left ventricle. An echo-free space is recorded in such cases on echocardiograms. It can be interpreted as pericardial exudate. Proceeding from an analysis of the results of ultrasonic investigation of 5 patients the authors have proposed some criteria for differential diagnosis between the gigantic left atrium and pericardial effusion.

[Recognition and differential diagnosis of pericardial and left-sided pleural effusions based on data from uni- and 2-dimensional echocardiography]. / Raspoznavanie i differentsial'naia diagnostika perikardial'nogo i levostoronnego plevral'nogo vypotov po dannym odno- i dvukhmernoi ékhokardiografii.

Sixty patients with pericardial and left-side effusions were singled out of 317 patients with pericarditis. A possibility to differentiate the position of liquid in adjacent cavities by means of one- and two-dimension echocardiography was shown. Peculiarities in the position of liquid with relation to the heart and one another lay in the basis of differential diagnosis. The use of simple technical methods in one-dimension echocardiography and the use of the two-dimension study make it possible to diagnose reliably pleural and pericardial effusions and their combination.

[The cardiovascular system in patients with chronic renal failure (echocardiographic data)]. / Sostoianie serdechno-sosudistoi sistemy u bol'nykh s khronicheskoi pochechnoi nedostatochnost'iu (po dannym ekhokardiografii).

Based on the study of the echocardiography data in 44 patients with chronic renal failure it has been shown that the incidence and the degree of left ventricle hypertrophy is related to the duration of arterial hypertension, increased cardiac output, and metabolic abnormalities. Echocardiographic studies made over time revealed a progressive deterioration of myocardial contractility. Pericarditis that ensues promotes the deterioration of left ventricle contractility and aggravates heart insufficiency. The diastolic murmur of aortal regurgitation should be differentiated as pertaining to infectious endocarditis or to relative insufficiency of the aortal valve. Two-dimensional echocardiography favours differentiation of left ventricle myocardial hypertrophy, makes it possible to locate the fluid in the pericardium more accurately, and to evaluate the treatment efficacy for pericarditis.

[Non-invasive mapping of cardiac electric potential of a specific quasi-epicardium]. / Neinvazivnoe kartirovanie élektricheskogo potentsiala serdtsa na sfericheskom kvaziépikarde.

A procedure was proposed for non-invasive mapping of the cardiac electrical potential or a spherical quasiepicardium from its synchronous multichannel measurement on the surface of the chest, i.e. routine electrocardiodraphic mapping. Mathematical simulation was used to demonstrate that the quasiepicardial potential can be calculated with the accuracy sufficient for clinical diagnosis by applying the multipole electric field resolution method with allowance made for three lowest resolution terms. Due to the fact that the spherical quasiepicardium is more approximate to the heart and more concentric as to its center than the chest surface, the maps of the quasiepicardial potential permit recognition of some features of the pattern of a cardiac electric process, which do not manifest themselves in the distribution of the potential on the body's surface. The examples showing that the assessment of a cardiac abnormality can be made more accurate by using this method are given in the paper.

[Transesophageal echocardiography in diagnosis of infectious endocarditis]. / Chrespishchevodnaia ékhokardiografiia v diagnostike infektsionnogo éndokardita.

Transthoracic and transesophagal echocardiography (TT EChG and TE EChG) were performed in 43 patients with infectious endocarditis (IE). Sensitivity and specificity of TE EChG in detection of vegetations were higher (92 and 75%, 81 and 50% for TE EChG and TT EChG, respectively). Vegetations and thromboembolism were unrelated. With TE EChG, morphologically verified perforations of valvular cusps were revealed 3 times more frequently than with TT EChG. Along with detection of vegetations and dysfunction of the prosthetic valve, an essential diagnostic marker of IE of the artificial valve is visualization of paraprosthetic fistulas in 2 of 5 patients. Indications for TT and TE EChG and techniques of their performance are described. TT EChG is used in screening for IE. TE EChG is conducted in complications of IE.