Nonisospectral integrable nonlinear equations with external potentials and their GBDT solutions

Auxiliary systems for matrix nonisospectral equations, including coupled NLS with external potential and KdV with variable coefficients, were introduced. Explicit solutions of nonisospectral equations were constructed using the GBDT version of the B\"acklund-Darboux transformation

INVERSE SCATTERING TRANSFORM ANALYSIS OF STOKES-ANTI-STOKES STIMULATED RAMAN SCATTERING

Zakharov-Shabat--Ablowitz-Kaup-Newel-Segur representation for Stokes-anti-Stokes stimulated Raman scattering is proposed. Periodical waves, solitons and self-similarity solutions are derived. Transient and bright threshold solitons are discussed.Comment: 16 pages, LaTeX, no figure

Search for invisible decays of sub-GeV dark photons in missing-energy events at the CERN SPS

We report on a direct search for sub-GeV dark photons (A') which might be produced in the reaction e^- Z \to e^- Z A' via kinetic mixing with photons by 100 GeV electrons incident on an active target in the NA64 experiment at the CERN SPS. The A's would decay invisibly into dark matter particles resulting in events with large missing energy. No evidence for such decays was found with 2.75\cdot 10^{9} electrons on target. We set new limits on the \gamma-A' mixing strength and exclude the invisible A' with a mass < 100 MeV as an explanation of the muon g_\mu-2 anomaly.Comment: 6 pages, 3 figures; Typos corrected, references adde

COMPARATIVE ANALYSIS OF EFFICIENCY OF SEROLOGICAL SCREENING METHODS FOR EPIGENETIC AND COLON CANCER

Purpose: Comparative analysis serologic screening techniques of epigenetic and colon cancer for adequate screening and diagnostic algorithms for detection of colorectal cancer.Materials and methods: Surveyed 204 patients whose colon cancer was detected in screening activities. A control group consisted of 56 healthy people. Screening measures unite following techniques: Immunochromatographic fecal occult blood, determination of tumor markers in the blood (carcinoembryonic antigen, oncoantigens CA 19-9, CA 242), methylated DNA gene septins 9 in the blood. The ROC-analysis determined the significance of diagnostic tests and their aggregation.Results: Diagnostic efficacy of colon cancer screening by blood levels of CEA, CA 242 and CA 19-9, respectively, 40,4%, 50,8%, 51,7%. Epigenetic testmetilat DNASEPT9of blood as screening method is characterized by a high diagnostic sensitivity-85,3%.Summary: At the initial stage of colon cancer screening method is a combination of the optimal combination of immunochemical test for the occult blood in feces in the threshold of 100 ng/ml, metilat DNA detection of SEPT9 gene in the blood

A new design for a green calcium indicator with a smaller size and a reduced number of calcium-binding sites

Genetically encoded calcium indicators (GECIs) are mainly represented by two- or one-fluorophore-based sensors. One type of two-fluorophore-based sensor, carrying Opsanus troponin C (TnC) as the Ca2+-binding moiety, has two binding sites for calcium ions, providing a linear response to calcium ions. One-fluorophore-based sensors have four Ca2+-binding sites but are better suited for in vivo experiments. Herein, we describe a novel design for a one-fluorophore-based GECI with two Ca2+-binding sites. The engineered sensor, called NTnC, uses TnC as the Ca2+-binding moiety, inserted in the mNeonGreen fluorescent protein. Monomeric NTnC has higher brightness and pH-stability in vitro compared with the standard GECI GCaMP6s. In addition, NTnC shows an inverted fluorescence response to Ca2+. Using NTnC, we have visualized Ca2+ dynamics during spontaneous activity of neuronal cultures as confirmed by control NTnC and its mutant, in which the affinity to Ca2+ is eliminated. Using whole-cell patch clamp, we have demonstrated that NTnC dynamics in neurons are similar to those of GCaMP6s and allow robust detection of single action potentials. Finally, we have used NTnC to visualize Ca2+ neuronal activity in vivo in the V1 cortical area in awake and freely moving mice using two-photon microscopy or an nVista miniaturized microscope

Search for Axionlike and Scalar Particles with the NA64 Experiment

We carried out a model-independent search for light scalar (s) and pseudoscalar axionlike (a) particles that couple to two photons by using the high-energy CERN SPS H4 electron beam. The new particles, if they exist, could be produced through the Primakoff effect in interactions of hard bremsstrahlung photons generated by 100 GeV electrons in the NA64 active dump with virtual photons provided by the nuclei of the dump. The a(s) would penetrate the downstream HCAL module, serving as shielding, and would be observed either through their $a(s)\to\gamma \gamma$ decay in the rest of the HCAL detector or as events with large missing energy if the a(s) decays downstream of the HCAL. This method allows for the probing the a(s) parameter space, including those from generic axion models, inaccessible to previous experiments. No evidence of such processes has been found from the analysis of the data corresponding to $2.84\times10^{11}$ electrons on target allowing to set new limits on the $a(s)\gamma\gamma$-coupling strength for a(s) masses below 55 MeV.Comment: This publication is dedicated to the memory of our colleague Danila Tlisov. 7 pages, 5 figures, revised version accepted for publication in Phys. Rev. Let

Algebraic construction of the Darboux matrix revisited

We present algebraic construction of Darboux matrices for 1+1-dimensional integrable systems of nonlinear partial differential equations with a special stress on the nonisospectral case. We discuss different approaches to the Darboux-Backlund transformation, based on different lambda-dependencies of the Darboux matrix: polynomial, sum of partial fractions, or the transfer matrix form. We derive symmetric N-soliton formulas in the general case. The matrix spectral parameter and dressing actions in loop groups are also discussed. We describe reductions to twisted loop groups, unitary reductions, the matrix Lax pair for the KdV equation and reductions of chiral models (harmonic maps) to SU(n) and to Grassmann spaces. We show that in the KdV case the nilpotent Darboux matrix generates the binary Darboux transformation. The paper is intended as a review of known results (usually presented in a novel context) but some new results are included as well, e.g., general compact formulas for N-soliton surfaces and linear and bilinear constraints on the nonisospectral Lax pair matrices which are preserved by Darboux transformations.Comment: Review paper (61 pages). To be published in the Special Issue "Nonlinearity and Geometry: Connections with Integrability" of J. Phys. A: Math. Theor. (2009), devoted to the subject of the Second Workshop on Nonlinearity and Geometry ("Darboux Days"), Bedlewo, Poland (April 2008

Completely integrable models of non-linear optics

The models of the non-linear optics in which solitons were appeared are considered. These models are of paramount importance in studies of non-linear wave phenomena. The classical examples of phenomena of this kind are the self-focusing, self-induced transparency, and parametric interaction of three waves. At the present time there are a number of the theories based on completely integrable systems of equations, which are both generations of the original known models and new ones. The modified Korteweg-de Vries equation, the non- linear Schrodinger equation, the derivative non-linear Schrodinger equation, Sine-Gordon equation, the reduced Maxwell-Bloch equation, Hirota equation, the principal chiral field equations, and the equations of massive Thirring model are gradually putting together a list of soliton equations, which are usually to be found in non-linear optics theory.Comment: Latex, 17 pages, no figures, submitted to Pramana

Risk of colorectal cancer in patients with general and intestinal symptoms taking into account the screening fecal occult blood

In the article evaluated the risk of colorectal cancer in identifying patients with intestinal and common symptoms with a positive test result for occult blood in feces by immunological method. In the examined the electronic records of the patient in a computer based 7853 regional consultative-diagnostic center of Rostov region. The 265 patients with colon cancer were identified. It is ascertained that when the positive test for the occult blood in feces in increased predictive value of common symptoms-anaemia and weight loss. Among patients with a positive result for occult blood in feces in haemoglobin blood levels of 110 g/l the risk of colorectal cancer was 22,9% at 100 g/l - 46,9% already, and with 90 g/l-72,5%. These same patients weight loss in 10% corresponded to the risk of colorectal cancer in 41,9%, weight loss 12% risk of colon cancer was 60,6%, while at lower weight at 15% increased by 82,6%.В статье проведена оценка риска колоректального рака при выявлении у больных кишечных и общих симптомов на фоне положительного результата теста на скрытую кровь в кале иммунологическим методом. В работе были проанализированы электронные записи о 7853 пациентах в компьютерной базе регионального консультативно-диагностического центра Ростовской области. У 265 больных был идентифицирован рак толстой кишки. Установлено, что при положительном результате теста на скрытую кровь в кале в наибольшей степени возросла прогностическая ценность общих симптомов - анемии и потери веса. Среди пациентов с положительным результатом на скрытую кровь в кале при достижении гемоглобином крови уровня 110 г/л риск колоректального рака был равен 22,9%, при достижении 100 г/л - уже 46,9% и при 90 г/л - 72,5%. У этих же больных потеря веса в 10% соответствовала риску колоректального рака в 41,9%, при потере веса 12% риск рака толстой кишки был 60.6%, а при снижении веса на 15% возрастал до 82,6%