A laser-plasma accelerator producing monoenergetic electron beams.

Particle accelerators are used in a wide variety of fields, ranging from medicine and biology to high-energy physics. The accelerating fields in conventional accelerators are limited to a few tens of MeV m(-1), owing to material breakdown at the walls of the structure. Thus, the production of energetic particle beams currently requires large-scale accelerators and expensive infrastructures. Laser-plasma accelerators have been proposed as a next generation of compact accelerators because of the huge electric fields they can sustain (>100 GeV m(-1)). However, it has been difficult to use them efficiently for applications because they have produced poor-quality particle beams with large energy spreads, owing to a randomization of electrons in phase space. Here we demonstrate that this randomization can be suppressed and that the quality of the electron beams can be dramatically enhanced. Within a length of 3 mm, the laser drives a plasma bubble that traps and accelerates plasma electrons. The resulting electron beam is extremely collimated and quasi-monoenergetic, with a high charge of 0.5 nC at 170 MeV.

Relativistic plasma control for single attosecond x-ray burst generation.

We show that managing time-dependent polarization of the relativistically intense laser pulse incident on a plasma surface allows us to gate a single (sub)attosecond x-ray burst even when a multicycle driver is used. The single x-ray burst is emitted when the tangential component of the vector potential at the plasma surface vanishes. This relativistic plasma control is based on the theory of relativistic spikes [T. Baeva, S. Gordienko, and A. Pukhov, Phys. Rev. E 74, 046404 (2006)]. The relativistic plasma control is demonstrated here numerically by particle-in-cell simulations.

Theory of high-order harmonic generation in relativistic laser interaction with overdense plasma.

High-order harmonic generation due to the interaction of a short ultrarelativistic laser pulse with overdense plasma is studied analytically and numerically. On the basis of the ultrarelativistic similarity theory we show that the high-order harmonic spectrum is universal, i.e., it does not depend on the interaction details. The spectrum includes the power-law part In proportional variantion for n(-8/3) for n < sqrt of 8 alpha gammamax3, followed by exponential decay. Here gammamax is the largest relativistic gamma factor of the plasma surface and alpha is the second derivative of the surface velocity at this moment. The high-order harmonic cutoff at proportional variantion gammamax3 is parametrically larger than the 4gammamax2 predicted by the simple "oscillating mirror" model based on the Doppler effect. The cornerstone of our theory is the new physical phenomenon: spikes in the relativistic gamma factor of the plasma surface. These spikes define the high-order harmonic spectrum and lead to attosecond pulses in the reflected radiation.

[Effect of a delayed type hypersensitivity reaction on the cytotoxic activity of macrophages, natural and antibody-dependent killer cells]. / Vliianie reaktsii giperchuvstvitel'nosti zamedlennogo tipa na tsitotoksicheskuiu aktivnost' makrofagov, estestvennykh i antitelozavisimykh killernykh kletok.

It is established that preparations which cause the delayed type hypersensitivity reaction (DTHR), such as old tuberculine of Koch (OTK) and staphylococcal phagolysate (SPL), being administered to mice sensibilized preliminary by BCG vaccine or staphylococcus, lead to considerable reinforcement of natural cytotoxicity of peritoneal macrophages and natural killer cells (NK-cells) and killer cells (K-cells) to a small extent. In the course of DTHR there is an increase in the ability of effector cells to bind with target ones (especially in macrophages) as well as in the quantity of cytolytic effectors. The cultural medium from macrophages of mice with DTHR which have internalized the opsonized particles of zymosan or have interacted with target cells P815, intensifies the activity of NK- and K-cells while the same medium from macrophages of intact animals possesses a depressed action on the NK- and K-cells activity. The cultural medium from spleen lymphocytes which mediated the NK- and K-cells activity of the intact animals as well as mice with DTHR does not influence cytotoxicity of macrophages.

[Methodological variants in the optimal determination of the activity of natural killers and mononuclear phagocytes by analysis at the single-cell level]. / Metodicheskie varianty optimal'nogo opredeleniia aktivnosti estestvennykh killerov i mononuklearnykh fagotsitov s analizom na urovne odnoi kletki.

Variants of the method for determination of the natural killer cells (NK-cells), and monocytes-macrophages both in human beings and in mice have been described. Usage of agarose which permits fixing conjugates of the effector cells and a tumour target cell allows determining simultaneously the quantity of effector cells bound with the target and percentage of the cytotoxic effectors. The results in acceptable definition of the effector cells' activity with the use of various kinds of plastic ware, its treatment, diverse types of agarose, temperature and time regimen are adduced. The di-target method of testing is approved using the target cells labelled with fluorescein as well as unlabelled ones. Peculiarities of function disturbances of the NK-cells and monocytes in patients with lung cancer as well as changes in the activity of these effectors in mice CBA depending on the terms of Krebs-2 carcinoma inoculation and on repeated BCG vaccine injection were detected.

[Immunity to embryonal stage-specific antigens in viral carcinogenesis]. / Immunitet k embrional'nym stadiospetsificheskim antigenam pri virusnom kantserogeneze.

The oncogenesis induced by the monkey SA7(C8) adenovirus in CBA/Ca mice has shown that immune responses to embryonal antigens are formed at early stages of the latent period and are preserved for a long time reaching the maximum by the 30th day of the latent period. The observed immune response to early embryonal antigens is considered as a factor of the tumour growth immunostimulation and also as a condition limiting the antitumour immunity.

[Immune system status under effect of low levels of ionizing radiation:studies within the 10 kilometer zone of accident at Chernobyl nuclear plant]. / Sostoianie immunnoi sistemy pri vozdeistvii malykh urovnei ioniziruiushchei radiatsii: issledovaniia v 10-kilometrovoi zone avarii na ChAES.

A study was made of the influence of high radiation contamination within the ten-kilometer zone of Chernobyl disaster on the structure and function of the immune system of (DBA x C57B1)F1 and DBA mice. The cumulative radiation doses with respect to gamma-radiation, were 0.024, 0.168 and 0.336 Gy. T-lymphocyte proliferation was shown the be activated with all radiation doses mentioned above but with doses of 0.024 and 0.168 Gy, helper T lymphocytes, and with 0.336 Gy, suppressor N-lymphocytes were primarily activated. So, in the former case, some effector functions of the immunity were activated, and in the latter, inhibited. It is concluded that certain hyperstimulation of the lymphoid cell formation (including the increase in T-suppressors), that is induced by long-term exposure to low-level radiation, triggers the mechanisms of autonomous regulation of the system that suppress the radiation-induced lymphocyte proliferation and inhibit the effector functions of the immunity.

[Effect of delayed hypersensitivity due to Staphylococcus or BCG vaccine on the sensitivity of animals to infection with heterologous bacteria or influenza virus]. / Vliianie giperchuvstvitel'nosti zamedlennogo tipa, vyzvannoi stafilokokkom ili vaktsinoi BTsZh, na chuvstvitel'nost' zhivotnykh k zarazheniiu geterologichnymi bakteriiami ili virusom grippa.

Experiments on mice of different strains have demonstrated that sensitization with BCG vaccine slightly increases resistance to infection with Francisella tularensis, Escherichia coli 819 and influenza A2 virus in mice of those strains which are capable of developing a high level of delayed hypersensitivity (DH). On the contrary, sensitization with Staphylococcus aureus b-243 decreases this resistance. A sharp increase in resistance to infection has been achieved in sensitized animals receiving DH-inducing specific antigen (old tuberculin or staphylococcal phagolysate) 24 hours before inoculation. This increased resistance to infection is due mainly to the eliminating capacity of the reticuloendothelial system and not to the bactericidal factors of the serum. The level of sensitization and the manifestation of DH reaction have been found to be genetically determined and to govern the degree of activation of nonspecific immunity.

[Delayed hypersensitivity and nonspecific cellular immunity. The role of mono- and polynuclear phagocytes]. / Giperchuvstvitel'nost' zamedlennogo tipa i nespetsificheskii kletochnyi immunitet. Rol' mono- i polinuklearnykh fagotsitov.

Differences in the influence produced by sensitization with BCG vaccine and Staphylococcus aureus and by the reaction of delayed hypersensitivity (DH) induced, respectively, by the injection of old tuberculin and staphylococcal phagolysate on the phagocytic activity of peritoneal macrophages and blood leukocytes in different animals were experimentally demonstrated. A considerable activation of the bactericidal and ingesting functions of macrophages was observed in animals showing a pronounced DH reaction (rabbits, guinea pigs and mice), while in Wistar rats no such activation was noted. The latter showed no DH reaction after sensitization with BCG vaccine and the injection of the specific antigen. Among different strains of mice, the activation of macrophages occurred in the animals with the most pronounced DH reaction. Sensitization with BCG vaccine led to an insignificant sensitization of macrophages, and sensitization with S. aureus even suppressed the phagocytic activity of macrophages. The treatment of mice with antimacrophagal preparations (carrageenan, silica and trypan blue, but T-lymphocyte antiserum) before and after the injection of the specific antigen into the sensitized animals abolished the stimulation of anti-infection immunity.

[Delayed hypersensitivity and nonspecific cellular immunity. The cytotoxic activity of macrophages, natural and antibody-dependent killer cells]. / Giperchuvstvitel'nost' zamedlennogo tipa i nespetsificheskii kletochnyi immunitet. Tsitotoksicheskaia aktivnost' makrofagov, estestvennykh i antitelozavisimykh killernykh kletok.

The experiment on (BALB/cXC57BL)F1 mice, showing a high level of delayed hypersensitivity (DH) when sensitized with BCG vaccine and Staphylococcus aureus strain B-243, has demonstrated the influence of such sensitization and DH reaction induced by the injection of a specific antigen (old tuberculin or staphylococcal phagolysate) into the sensitized animals on the cytotoxicity of macrophages, natural killers (NK) and antibody-dependent killers (ADK). Sensitization with BCG vaccine alone results in an insignificant rise in the activity of these effector cells, and sensitization with S. aureus produces no changes at all. The pronounced activation of the cytotoxicity of macrophages, NK and, to a lesser extent, ADK has been observed in DH reaction induced by the injection of a specific antigen into the sensitized mice. In the course of DH reaction a rise in the activity of NK and ADK not only against tumor target cells, but also against microbial ones (Candida albicans and S. aureus) has been found to occur.

[Delayed hypersensitivity and nonspecific cellular immunity. The conditions determining the maximally expressed immunity activity]. / Giperchuvstvitel'nost' zamedlennogo tipa i nespetsificheskii kletochnyi immunitet. Usloviia, opredeliaiushchie maksimal'no vyrazhennuiu aktivnost' immuniteta.

In vivo experiments on the infection of mice with influenza A virus and Francisella tularensis and in vitro experiments on the bactericidal activity of macrophages have demonstrated the conditions leading to the maximally pronounced activation of immunity by means of preparations inducing delayed hypersensitivity (DH). The following conditions have been determined: the presence of pronounced DH previously to the injection of old tuberculin (OT) and staphylococcal phagolysate (SP) used as challenge antigens, the specificity and peculiar features of the antigenic structure of the challenge agent, the time of its administration after the course of multiple sensitizing injections of BCG and staphylococci, the dosage of OT and SP and the scheme of their administration, the desirability of their local use. The time of the maximum activation of cell-mediated immunity after the injection of OT and SP to sensitized animals with a high level of DH and the duration of such activation have been established.

[Elimination of phenylalanine from amino acid mixtures obtained from yeast hydrolysates and autolyzates]. / Udalenie fenilalanina iz smesei aminokislot, poluchaemykh iz gidrolizatov i avtolizatov drozhzhei

In order to obtain amino acid mixtures devoid of phenylalanine, adsorption of aromatic amino acids was studied during their chromatography on ion-exchange resin IA-Ip. When 40 g of the amino acid mixture were passed through 400 ml of the swollen ion-exchange resin, phenylalanine and tyrosine were eliminated and 67% of dry substance were yielded. Ion-exchange resin adsorbed phenylalanine and tyrosine could be regenerated. The use IA-Ip is advantageous as compared with that of ion-exchange resin Amberlite IR-45 and activated charcoal.

[The effect of autolysis on characteristics of amino acid mixtures, obtained using ethanol-assimilating yeasts]. / Vliianie uslovii avtoliza na kharakteristiki aminokislotnykh smesei, poluchennykh s ispol'zovaniem étanolassimiliruiushchikh drozhzhei.

The influence of the enzyme preparation - macerate, concentration of the yeast biomass in the reaction medium, and chloroform on the autolysis of the ethanol assimilating yeast Saccharomyces cerevisiae BKM-Y-2656, BKM-Y-2465, and the baker's yeast r. L-2 was studied. Amino acid mixtures were isolated from the yeast autolysates. The use of macerate and a decrease in the biomass concentration were shown to increase the yield of the amino acid mixtures. The use of chloroform positively influenced the baker's yeast autolysis. Conditions of the joint action of these factors on the intensification of the process of the amino acid mixtures preparation based on the autolysis were determined.

[Effect of ultrasonic treatment on the intensification of processes for obtaining amino acid mixtures from ethanol-assimilating yeasts]. / Vliianie ul'trazvukovoi obrabotki na intensifikatsiiu protsessa polucheniia aminokislotnykh smesei iz assimiliruiushchikh étanol drozhzhei.

We studied the effects of ultrasound treatment on an increase of the yield of amino acid mixtures from autolysates of Saccharomyces cerevisiae VKM-Y-2465 grown on ethanol. Adding 2% chloroform (activating agent), autolysis for 5-10 h, and ultrasound treatment of autolysates allowed us to obtain mixtures balanced in lysine, methionine, and tryptophan and containing up to 90% free amino acids.

[Amino acid makeup of preparations from baker's yeast autolysates]. / Aminokislotnyi sostav preparatov iz avtolizatov pekarskikh drozhzhei.

Yeast autolysis and hydrolysate composition were studied with respect to the autolysis of baker's pressed yeast. A method of isolating a mixture of amino acids and lower peptides from autolysates was developed, using ion-exchange resins. The above compounds reached maximum accumulation by the 15-20th hour of autolysis. A mixture of amino acids applicable to nutrition, including dietotherapy, was prepared.

[Effect of sensitization and delayed hypersensitivity reaction on tumor growth in mice]. / Vliianie sensibilizatsii i allergicheskoi reaktsii zamedlennogo tipa na rost opukholi u myshei.

Mice BALB/c during 8--10 weeks were sensitized by percutaneous injections of BCG vaccine or living B-243 staphylococci weekly, and after 10 days they were inoculated isogenic adenocarcinoma "Akatol". Compared with the control animals the tumor growth was found to be retarded. A more considerable retardation of the growth and in 50% the complete tumor regression was noted in sensitized mice, which repeatedly, since the day of inoculation, were injected subcutaneously or intratumorously alttuberculin or staphylococcic phagolysate, respectively. A gain of the tumor mass was associated with concomitant lessening of skin edema in response to test-allergen injection. Injections of alttuberculin in BCG-sensitized mice C3H/He contribute to an increased cytotoxicity of peritoneal macrophages against the cells of mammary gland isogenic tumor.

[Cryosurgery of stage I-II basal cell skin cancer and its effect on various immunologic indices]. / Kriokhirurgiia bazal'no-kletochnogo raka kozhi I-II stadii i ee vliianie na nekotorye pokazateli immuniteta.

87 patients were treated by cryosurgery for stage I-II basal cell skin cancer. Changes in immunologic parameters were followed prior to and during surgery in 23 patients. Cryosurgery proved highly effective. Cryodestruction brought about an insignificant suppression of T-lymphocyte system. Most immunologic indexes returned to normal on day 21. Other systems of cellular and humoral immunity were not affected.

[Activation of natural antitumor resistance in cancer patients during a delayed hypersensitivity reaction]. / Aktivatsiia estestvennoi protivoopukholevoi rezistentnosti u onkologicheskikh bol'nykh pri reaktsii giperchuvstvitel'nosti zamedlennogo tipa.

Factors influencing the effectiveness of BCG vaccine employed as part of complex therapy were studied in cases of lung and gastrointestinal cancer. The drug showed clinical effect and stimulated the effector function of monocytes, natural and antibody-dependent killers in tuberculin-positive patients only. The degree of stimulation was in correlation with that of delayed hypersensitivity reaction. A relationship between stimulation, increase in the level of effector-cells and intensification of cytolytic activity was established.

[The correction of the immune system by using the immunomodulator ribomunyl in patients with recurrent respiratory tract infections]. / Korrektsiia immunnoi sistemy s pomoshch'iu immunomoduliatora ribomunila u bol'nykh s retsidiviruiushchimi infektsiiami respiratornogo trakta.

Children and adults with chronic ENT and bronchopulmonary infections took ribomunyl tablets (Pierre Fabre) under immunological control. Even a 3 week course led to obvious clinical improvement of their condition in acute stage. Investigation of populations and subpopulations of lymphocytes showed that ribomunyl mainly increases the number of CD3+, CD3+4+, CD3-/16+56-, CD4+25+, CD4+69+, CD56+25+. CD56-25+ and CD8-38+ cells that is increased the number of T-, T-n and NK-cells and also increased expression on T-n and NK-cells of activation antigens. An increase in quantity and activation of these cells was more expressed in patients with initially smaller number of these cells and correlated with the treatment efficacy. Ribomunyl enhanced effector function of NK-cells, phagocytes (monocytes and granulocytes), this activation being more in patients with marked clinical effect. Ribomunyl appeared effective in Chernobyl accident victims also. A long-term course of ribomunyl (6 months) showed better clinical effect when compared to 3-week course.

[Effectiveness of various programs of immunocorrective therapy in chronic infectious-inflammatory diseases]. / Effektivnost' razlichnykh skhem immunokorrigiruiushchei terapii khronicheskikh infektsionno-vospalitel'nykh zabolevanii.

An immunological study of patients with chronic pneumonia, osteomyelitis, pyoderma and candidosis showed various changes in cellular immunity values within each nosological group of examined patients. The efficacy of levamisole therapy was higher in the group of patients where an increase in the number of E-rosette forming cells and NBT-test values by more than 10% was noted in vitro in the presence of 10 micrograms/ml of levamisole as opposed to patients with a less increase in these values or their decrease. Nonspecific immunotherapy (levamisole, prodigiosan) following specific immunotherapy (staphylococcal anatoxins and antiphagin or autovaccines) proved to be more effective in the treatment of patients with chronic infectious inflammatory diseases than the reverse sequence of immunotherapy courses.