On costa variation in leaves of fossil permian protoshagnalean mosses

Leaves of extinct mosses of the order Protosphagnales are studied with the special attention to their different developmental stages. A previously unknown morphotypes without costa and with very short costa are revealed in this group. It is characteristic for young small leaves of Kosjunia and Intia , but apparently does not occur in other genera of this fossil order. The present collection allows restore a heteroblastic series in these leaves and associated with it differentiation of laminal areolationyesBelgorod State National Research Universit

Investigation on the Effect of Application of Monopolar Electrocoagulation for Endoscopic Haemostasis in Bleeding Peptic Ulcers

The authors investigate the effect of application of monopolar electrocoagulation for endoscopic haemostasis in bleeding peptic ulcers. In group of 30 randomly selected patients with acute bleeding from gastroduodenal ulcers, classified after Forrest by Wirtz we apply endoscopic electrocoagulation. The authors reveal that the method of monopolar high-frequent diathermal coagulation in present days is not appropriate for the purposes of endoscopic haemostasis in acute bleeding from gastroduodenal ulcers

Fractional and unquantized dc voltage generation in THz-driven semiconductor superlattices

We consider the spontaneous creation of a dc voltage across a strongly coupled semiconductor superlattice subjected to THz radiation. We show that the dc voltage may be approximately proportional either to an integer or to a half- integer multiple of the frequency of the applied ac field, depending on the ratio of the characteristic scattering rates of conducting electrons. For the case of an ac field frequency less than the characteristic scattering rates, we demonstrate the generation of an unquantized dc voltage.Comment: 6 pages, 3 figures, RevTEX, EPSF. Revised version v3: corrected typo

Superlattice with hot electron injection: an approach to a Bloch oscillator

A semiconductor superlattice with hot electron injection into the miniband is considered. The injection changes the stationary distribution function and results in a qualitative change of the frequency behaviour of the differential conductivity. In the regime with Bloch oscillating electrons and injection into the upper part of the miniband the region of negative differential conductivity is shifted from low frequencies to higher frequencies. We find that the dc differential conductivity can be made positive and thus the domain instability can be suppressed. At the same time the high-frequency differential conductivity is negative above the Bloch frequency. This opens a new way to make a Bloch oscillator operating at THz frequencies.Comment: RevTeX, 8 pages, 2 figures, to be published in Phys. Rev. B, 15 Januar 200

Morphological Changes in the Tissues Under The Action of Nd: YAG Laser in Peptic Ulcer Bleeding

The autors carry out a morphological study of 60 endoscopic biopsies of stomach mucosa followed-up consequencently in time. The study describes the morphological changes in the tissues under the action of Nd:YAG laser beam in cases of acute bleeding from peptic ulcers. Study proves that Nd:YAG LFC has lasting haemostatic and epithelising effect, i. e. it exerts a long-lasting therapeutic effect

Treatment recommendations for multimodality management of rectal cancer with a foc us on radiotherapy indications

Colorectal cancer (CRC) is one of the most commonly diagnosed cancer in Europe and US A and one of the leading causes of cancer death worldwide with 30% of all CRCs diagnosed in the rectum. Numerous published trials prove that the treatment of rectal cancer requires multidisciplinary approach. In this article the treatment recommendations for rectal cancer with an emphasis on radiotherapy (RT) application are defined

The role of radiotherapy in the contemporary multimodality management of rectal cancer

During the last 20 years the results of a significant number of trials concerning the multimodality management of rectal cancer have been published. This led to improvement of rectal cancer treatment. Radiotherapy (RT) is part of the standard multimodality treatment of rectal cancer and results in 50% local control improvement. The findings of the trials have answered some questions like the modalities sequencing, the combination of RT and chemotherapy, the RT fractionation regimens and the required total dose in addition to surgery either local or radical, the application of contact RT in early rectal cancer and intraoperative radiotherapy (IOR T) in locally advanced and recurrent rectal cancer. Neoadjuvant chemoradiation (CRT) followed by total mesorectal excision (TME) is the current standard treatment of patients with locally advanced rectal cancer with improved local control over postoperative CRT. In spite of the improved locoregional control, controversies exists and other opportunities for improvement are being investigated. In the present paper, the evidence behind the current standard of RT and the controversies in the treatment of patients with rectal cancer are reviewed

On the leaf morphogenesis of palaeozoic mosses of protosphagnales

New fossil moss collections with an excellently preserved anatomy, forming the Permian deposits of the Pechora Coal Basin, allow study leaves at different stages of development, thus revealing morphogenetic patterns of their lamina differentiation. In some respects, these patterns are different from those of modern mossesyesBelgorod State National Research Universit

Effect of ionization/recombination processes on the electrical interactions between positively charged particles in highly collisional plasmas

The effect of ionization and recombination processes on the electrical interactions between a pair of small charged particles in highly collisional plasmas is discussed. In particular, it is shown that these processes suppress the long-range attraction between positively charged particles. The condition corresponding to the vanishing of attraction is derived. The role of the effect for conditions of existing experiments is estimated