Superconductivity in highly disordered NbN nanowires.

The topic of superconductivity in strongly disordered materials has attracted significant attention. These materials appear to be rather promising for fabrication of various nanoscale devices such as bolometers and transition edge sensors of electromagnetic radiation. The vividly debated subject of intrinsic spatial inhomogeneity responsible for the non-Bardeen-Cooper-Schrieffer relation between the superconducting gap and the pairing potential is crucial both for understanding the fundamental issues of superconductivity in highly disordered superconductors, and for the operation of corresponding nanoelectronic devices. Here we report an experimental study of the electron transport properties of narrow NbN nanowires with effective cross sections of the order of the debated inhomogeneity scales. The temperature dependence of the critical current follows the textbook Ginzburg-Landau prediction for the quasi-one-dimensional superconducting channel I c âˆ¼ (1-T/T c)3/2. We find that conventional models based on the the phase slip mechanism provide reasonable fits for the shape of R(T) transitions. Better agreement with R(T) data can be achieved assuming the existence of short 'weak links' with slightly reduced local critical temperature T c. Hence, one may conclude that an 'exotic' intrinsic electronic inhomogeneity either does not exist in our structures, or, if it does exist, it does not affect their resistive state properties, or does not provide any specific impact distinguishable from conventional weak links.

[Delayed Copying of Unfamiliar Contour Shapes: Does Reaction Time Decrease with Growing Delay Reflect a Change in Internal Representation Of Fothcoming Movement?].

Group of 24 adults has performed the delayed reproduction (copying) of unfamiliar contour shapes (trajectory templates). Templates were shown for 250 ms and the participants were asked to reproduce them upon detecting acoustical go signal (short click). Go signal was delayed relatively to the end of a visual template exposure by T = 0, 500, 1000, 2000 or 4000 ms. Block design of the experiment was used when delay T was held constant within a block consisted of 32 trials. We analyzed reaction time (RT), mean movement time (MT) along a single segment of trajectory, and the mean dwell time (DT) in the vertices of the template. It is shown that RT does not depend monotonically on the delay T showing a decrease at T ≤ 1000 ms and increase at T ≤ 2000 ms. The RT of T curve is well described by a simple additive model that includes a linearly growing and an exponentially decaying terms. The linear growth reflects the foreperiod effect, i.e., decreasing capacity to predict an exact moment of go signal with the growing delay T [Niemi, Naatanen, 1981; Meulenbroek, Van Galen, 1988]. We suggested that exponentially decaying term may be caused by the internal representation of a trajectory undergoing some transformation during retention in the working memory.

[Delayed Copying of Unfamiliar Contour Shapes: Analysis of Potentials Related to Stimuli].

The high-density EEG was recorded and ERPs related to showing unfamiliar contour shapes and delivering imperative signal (a short sound) were estimated in the task requiring delayed motor reproduction of these shapes. A total of 22 right-handed adults participated in the experiment. They performed 5-blocks of trials corresponding-to 5 different delays (T= 0; 500, 1000, 2000 4000 ms) between the imperative signal relative to the end of the contour trajectory presentation. An ERP analysis showed that, unlike ERPs related to the contour shape presentation, those related to the imperative signal delivery do change with growing delay T. A subsequent analysis of cortical sources of the ERPs related to the imperative stimulus showed corresponding pronounced grows of reactivity of orbito-frontal cortex of the right hemisphere and a symmetrical bilateral grows of reactivity of dorsal parts of the sensorimotor cortex. The reported findings are discussed in the framework of the proposal according to which the internal representation of a trajectory undergoes a transi- tion from a sensory-specific format towards more abstract neither sensory- nor motor-specific format.

[A delayed motor production of open chains of linear strokes presented visually in static and dynamic modes: a comparison between 9 to 11 years old children and adults].

The production of drawing movements was studied in 29 right-handed children of 9-to-11 years old. The movements were the sequences of horizontal and vertical linear stokes conjoined at right angle (open polygonal chains) referred to throughout the paper as trajectories. The length of a trajectory varied from 4 to 6. The trajectories were presented visually to a subject in static (linedrawing) and dynamic (moving cursor that leaves no trace) modes. The subjects were asked to draw (copy) a trajectory in response to delayed go-signal (short click) as fast as possible without lifting the pen. The production latency time, the average movement duration along a trajectory segment, and overall number of errors committed by a subject during trajectory production were analyzed. A comparison of children's data with similar data in adults (16 subjects) shows the following. First, a substantial reduction in error rate is observed in the age range between 9 and 11 years old for both static and dynamic modes of trajectory presentation, with children of 11 still committing more error than adults. Second, the averaged movement duration shortens with age while the latency time tends to increase. Third, unlike the adults, the children of 9-11 do not show any difference in latency time between static and dynamic modes of visual presentation of trajectories. The difference in trajectory production between adult and children is attributed to the predominant involvement of on-line programming in children and pre-programming in adults.

[Internal representation of movement sequences built upon either static line drawings or trajectories of moving object].

In this paper, we explore the issue of the nature (perceptual, abstract, or motor) of neural codes used by CNS in order to store the internal representation of elements of a sequence of movements. Reported are the results of two experiments in which two independent groups of 16 right handed adults repeated, after a given delay, the piecewise trajectories (open polygonal chains) using the graphical tablet. A trajectory was shown either as a static line-drawing (static mode) or a small moving pointer (dynamic mode). The results show that: 1) for the delay varying from 0 to 1 s, the latent time of the trajectory production is greater in the dynamic than in the static mode, with the latent time is no different under to presentation conditions when the production delay reaches 3 s; 2) the latent time is exponentially decaying as the trajectory production delay increases from 0 to 3000 ms, with the characteristic decay time being different in the static (377 ms) and the dynamic (656 ms) presentation modes. The results of the present study are in line with the view that the internal representation of the sequence of movements is perceptual and it is converted into the motor codes at the later stages prior to movement execution. It is suggested in the paper that the observed exponential decay of the latent time might be related to the transformation of the early sensory (iconic) representation into the perceptual trajectory representation.

[Use of native and lyophilized Loewenstein-Jensen's solid media in determining drug resistance on mycobacterium tuberculosis strains]. / Ispol'zovanie nativnoi i liofilizirovannoi sred Levenshteina-Iensena dlia opredeleniia lekarstvennoi ustoichivosti mycobacterium tuberculosis.

The results of determination of drug medium depend on both individual cultural properties of the strains tested and the type of the medium used. The composition of a medium is of significance for some strains: the latter grow in any medium and are characterized by the same spectrum of resistance. However, most drug-resistant strains have higher feeding demands which are not fully met on the lyophilized Löwenstein-Jensen medium. The strains in the lyophilized medium show an incomplete spectrum of resistance and less grow than do those in freshly prepared Löwenstein-Yersen medium.

[Biological properties of laboratory strains and clinical isolates of mycobacteria multiresistant to antitubercular preparations]. / Biologicheskie svoistva laboratornykh shtammov i klinicheskikh izoliatov mikobakterii, polirezistentnykh k protivotuberkuleznym preparatam.

Multiresistant M. tuberculosis strains show varying drug resistance, virulence and growth rates. The count of cells of some multiresistant strains in the guinea-pig parenchymatous organs after intracardiac inoculation was comparable with that of after inoculation with clinical isolates. Furthermore, some multiresistant strains were not inferior to sensitive clinical isolates. The findings lead to the conclusion that there is a wide range in the virulence of multiresistant strains and hence they can present an epidemiological hazard.

[Diagnosis, clinical picture and treatment policy in acute progressive forms of pulmonary tuberculosis under present-day epidemiological conditions]. / Diagnostika, klinika i taktika lecheniia ostroprogressiruiushchikh form tuberkuleza legkikh v sovremennykh épidemiologicheskikh usloviiakh.

Among 103 examinees, the most common clinical type was caseous pneumonia (45.6%), progressive fibrocavernous tuberculosis (20.4%), infiltrative caseous pneumonia (17.5%), disseminated tuberculosis (16.5%). Progression was characterized by cavern formation in 91.1% of patients, with large and giant caverns containing nonspecific microbes forming in 79.6%. All the patients were found to isolate bacteria and 93.5% showed their excess. Drug-resistant microbes were identified in 62.1% of patients; polydrug resistance was seen in 37.5%. Chemotherapy was performed at the first stage by using 5 drugs: isoniazid, rifampicin, pyrazinamide, ethambutol plus kanamycin or amikacin. A combination of reserve drugs, including prothionamide, ofloxacin (ciprofloxacin) amikacin, pyrazinamide, and ethambutol, was used in patients with polyresistance. Symptomatic and pathogenetic therapies should aim at correcting complications and concomitant abnormalities. Following 6 months, 80% of patients stopped isolating bacteria, the process became stable and they could be prepared for planned surgical treatment. In 20% of cases, the process was progressive and it required salvage operations.

[The corrective action of limontar in metabolic disorders in the mother-fetus system caused by ethanol exposure during pregnancy]. / Issledovanie korrigiruiushchego deistviia limontara pri obmennykh narusheniiakh v sisteme mat'--plod, vyzvannykh vozdeistviem étanola vo vremia beremennosti.

It was established in experiments on nonbred albino rats that injection of limontar (1 mg/kg) in the fetal period of pregnancy in alcoholic intoxication (6 g/kg) leads to weight loss by the female, normalization of the character of behavior and metabolic shifts in the organism, and removal of the symptoms of excitation of the sympathetic link of cardiovascular system regulation. No harmful effect of limontar on the mother-fetus biosystem was detected.

[New possibilities for metabolic protection from hypoxia in pregnant rats and their progeny]. / Novye vozmozhnosti metabolicheskoi zashchity ot gipoksii beremennykh krys i ikh potomstva.

Individual resistance of pregnant rats and the newborns to acute hypoxic hypoxia was studied. It was found that individual resistance of the organism to hypoxia significantly decreases in the last period of pregnancy. A new drug limontar proved to possess the properties of an active antihypoxia agent. Its administration during the last third of pregnancy stimulated the organism's protective-adaptational reactions, increased the resistance of pregnant, rats and the newborns to hypoxia. Limontar significantly improves the mechanometabolic indices of an isolated perfused heart under hypoxic conditions. Analysis of the obtained data suggests that limontar increases energy formation in the myocardium through activation of a more efficient and energetically beneficial path of succinic acid oxidation.

[The detection of mycobacteria in children and adolescents by using the polymerase chain reaction]. / Vyiavlenie mikobakterii s pomoshch'iu polimerazno-tsepnoi reaktsii u detei i podrostkov.

A polymerase chain reaction (PCR) was used for determination of mycobacterial DNA in clinical samples from children and adolescents. The results were positive in 23 and 53% of cases, respectively, while standard microbiological methods failed to show presence of any bacteria in the samples. Case histories contained information on high incidence of positive Mantoux test. Microbiologically the diagnosis was confirmed only in 7 adolescents. In children mycobacteria were not found.

[Use of microscopy and inoculation for bacteriologic diagnosis in tuberculosis patients by the materials of Ivanovo region]. / Ispol'zovanie mikroskpii i poseva dlia diagnostiki bacteriovydeleniia u bol'nykh tuberkulezom po materialam Ivanovskoi oblasti.

The paper describes guidelines for isolation of Mycobacterium tuberculosis by bacterioscopy. It shows high detection rates for Mycobacteria in patients included into the programme. The detection rates of patients by bacterioscopy are not different in two quarters.

[The corrective properties of glycine in alcoholic intoxication in the fetal period of pregnancy]. / Korrigiruiushchie svoistva glitsina pri alkogol'noi intoksikatsii v plodnyi period beremennosti.

Natural metabolite glycine administered per os to rats in the fetus period of pregnancy in a dose of 1 mg/kg was found to exert a corrective action with respect to the toxic effect of ethanol in the mother-fetus system. Glycine prevents loss in the body weight, normalizes functional state of the nervous system and metabolic disorders in the maternal organism, improve the redox processes in the lymphocytes changed under alcoholization, and protect the fetus both on the metabolic and microstructural levels.

[S and R forms of Mycobacterium tuberculosis as a problem of producing cloned and phenotypically competent strains]. / S- i R-formy Mycobacterium tuberculosis kak problema polucheniia klonirovannykh i fenotipicheski polnotsennykh shtammov.

The authors suggest that animals and humans carry M. tuberculosis in S form. These mycobacteria are virulent, do not form conglomerates and represent biologically most potent form. The state of R-form M. tuberculosis results from their culturing on artificial culture media which fail to secure compatible conditions for cells. M. tuberculosis S-form is convenient for microbiological and molecular-genetic research. The authors offer a method of biological production of single M. tuberculosis in S form.

[New microbiological Techniques in diagnosis of tuberculosis]. / Primenenie novykh mikrobiologicheskikh tekhnologii v diagnostike tuberkuleza.

Microbial spectrum in patients with disorders of the upper respiratory tract consisted mainly of streptococci, staphylococci and pneumococci in 1991-1993, 1994 and later, respectively. Most specific for detection of nontuberculous flora was brushing with protecting agar plugs in combination with transport medium and anaerobic culturing. Direct immunofluorescence allows detection of antigens M. chlamydia in 29.4%, M. pneumoniae in 18.5% of cases. In diagnosis of tuberculosis the following new technologies were introduced: bacterioscopy with previous culturing of the material on liquid culture media followed by biological test and polymerase-chain reaction; determination of drug resistance based on nitrate reductase activity of M. tuberculosis indicating resistance of M. tuberculosis on liquid media in 4-7 days, dense egg media in 8-12 days, usage of Popesku medium enables correction of tuberculosis chemotherapy one month after the test initiation; M. tuberculosis identification using Western blot with monoclonal antibodies in some cases for 7 days.

[Efficacy of chemotherapy of pulmonary tuberculosis drug-resistant m.tuberculosis]. / Effektivnost' khimioterapii tuberkuleza legkikh s lekarstvenno-ustoichivymi mikbakteriiami.

M. tuberculosis examined in 717 patients with pulmonary tuberculosis appeared resistant to chemotherapy in 67.2% of cases. Whereas chronic patients developed drug resistance (DR) as secondary DR in 90.2% of cases, new cases with DR (50.1% of the examinees) seemed to be infected with drug-resistant M. tuberculosis. 2-stage chemotherapy with 4-5 drugs terminates bacterial discharge within first 3 months of treatment in the majority of the patients, especially if early correction of chemotherapy is used by the results of early determination M. tuberculosis drug sensitivity.

[The protective action of limontar in pregnant animals with acute hypoxic hypoxia]. / Protektornoe deistvie limontara na beremennykh zhivotnykh pri ostroi gipoksicheskoi gipoksii.

A comparative study of individual resistance of rats to acute hypoxic hypoxia was performed. It was shown that individual resistance of the organism to hypoxia significantly decreases in the course of pregnancy. Limontar is shown to be active antihypoxant. Limontar administered during the last third of pregnancy stimulates protective-adaptive reactions in the females, thus increasing their resistance to hypoxia.