Withdrawal of radiotherapy in patients with brain tumors under four years decreases chance for cure. AutoHSCT in a series of pilot studies demonstrated a potential to improve outcomes in these ...patients. The study included 50 patients with median age of 39 months (7-53). Medulloblastoma (n = 28, 56%), ETMR (n = 9, 18%) and other histological types (n = 13, 26%) were most commonly diagnosed. Forty two patients (84%) received tandem autoHSCT by HIT-MED protocol, and single autoHSCT was performed in eight children (16%). Adjuvant radiotherapy was administered in 25 (50%) children and treatment of relapse included radiotherapy in 6 (12%). Median follow-up was 39.6 months (6-121). Long-term CIR was 37%, and TRM - 6%. Five-year OS was 71% in medulloblastoma, 37% in ETMR and in other tumors - 51% (p = 0.07). Irradiation-free OS at 5 years for children with medulloblastoma was 24%. For the whole cohort of CNS tumors, independently of histology, OS and PFS at five years were 60% and 46%, respectively Young children with medulloblastoma, following tandem autoHSCT, demonstrate OS comparable to older children. Patients with other histological types demonstrate suboptimal long-term survival rates after autoHSCT and one should assess whether these patients benefit from autoHSCT.
A direct current streamlined loop formed by two diametrically opposite spirals of a linear or ribbon wire is a deflector for nonrelativistic electrons and a spiral undulator for relativistic ...electrons. In this work, analytical expressions are obtained for the three components of magnetic induction inside a two-wire spiral line (TSL), which differ significantly from similar expressions used in scientific works. In particular, in the paraxial region, where electrons interact with the magnetic field, the radial component of the magnetic induction is not an increasing function of the radial coordinate, but a decreasing one. This result is important because the description of the physical characteristics of a free-electron laser or deflector requires taking into account the exact trajectories of the bunch electrons. The obtained correct formulas for the potential of the magnetic field and the components of the magnetic induction are also necessary to determine the values of the resonant frequencies of electromagnetic waves excited by a quasi-stationary sinusoidal voltage inside the TSL.
Pelvic floor insufficiency (PFI) is one of the most common and understudied gynecological diseases. PFI is a major public health problem that will steadily increase due to population aging. The ...issues of early diagnosis remain unresolved. Physical examination remains the primary method of evaluating PFI, but manual examination alone is not enough to diagnose hidden pelvic floor (PF) defects. Topical verification of muscular and fascial PF defects is necessary to route patients for non-surgical or surgical treatment. 2D/3D transperineal sonography is a non-invasive, simple, and the most common method of imaging PF structures.
•Solitary wave solutions of Whitham equation with resonance dispersion relation are considered.•An existence of smooth and singularity containing solitons, bound states of the solitons and localized ...solutions with oscillating asymptotics is established.•Velocity spectra of exponentially localized travelling waves appear to be discrete.•Asymptotic “quantization rules” for calculation of spectra are obtained.
Localized stationary solutions of nonlinear nonlocal Whitham equation with resonance dispersion relation are considered. The existence of exponentially localized smooth and singular solitons, bound states of the solitons and localized solutions with oscillating asymptotics is recognized. The velocity spectra of solitons, in contrast to all other known Whitham equations, appear to be discrete. Asymptotic “quantization rules” for calculation of discrete spectra are obtained.
The undulator radiation of positrons channeled in a crystalline undulator with sections (CUS) is investigated theoretically taking into account the effect of dielectric polarization of the ...crystalline medium. The configuration of CUS preserves planar channeling of positrons with a given energy. An analytical expression is obtained for the spectral distribution of the number of radiated photons. The features of this spectrum are presented. As expected, such a modification of the crystalline undulator results in the gain of radiation owing to the constructive interference of the radiation fields formed in separate sections. The optimal parameters of the CUS are found. Such micro-emitters will find wide practical applications because they generate directional beams of both hard and soft photons.
The problem of the radiation of a relativistic bunch of positrons channeled in densely packed nanotubes was solved. A model parabolic potential was used for the average nanotube field. The channeled ...positrons oscillate with the same frequency, but with different amplitudes equal to the distance from the point of entry of the positron in the nanotube to its axis. The polarization of the nanotube environment results in the appearance of a lower energy threshold for the formation of radiation. The boundaries of the frequency interval of radiation also depend on the amplitude of the oscillating positron. For the first time an analytical expression for the spectrum of the total radiation is obtained in the dipole approximation. At a zero angle, both hard (gamma) and soft (X-ray) photons are generated. Directed photon beams have important practical applications.
Nanocrystals of lead sulfide were grown in TiO2 (titania) thin films prepared by a sol-gel process. The synthetic procedure as well as the structural, optical, and electrical properties of the films ...are demonstrated. The structures and morphology of PbS nanocrystals were analyzed using HRTEM, SAED, AFM, HRSEM, XRD and EDAX elemental analysis technique. When the concentration of PbS in the titania matrix is 20 mol%, PbS NCs with a diameter of 2.0 nm are created. At a higher PbS concentration (> 40 mole%) in the titania matrix, PbS NCs and PbS clusters are created not only within the TiO2 film but also on the external surface of the TiO2 film. By increasing the PbS concentration up to 50 mol%, PbS nanocrystals of 6–8 nm in diameter are formed within the titania film and PbS clusters with a base size of about 100 nm2 and a height up to about 20 nm were self assembled on the external surface of TiO2 film. Quantum size effect and band gap energies were obtained from shifts of the absorption edge. For electrical measurements, PbS–TiO2 films were deposited on an ITO/glass substrate, and then covered with gold contact. The electrical properties of ITO/PbS NCs–TiO2/Au and ITO/PbS NCs–TiO2/PbS cluster/Au structures were studied. I–V characteristics of the one layer structure are nearly linear and symmetric, while those of the two-layer structure exhibit rectifying behavior.
