Temporal Development of a Laser-Induced Helium Nanoplasma Measured through Auger Emission and Above-Threshold Ionization.

Femtosecond pump-probe electron and ion spectroscopy is applied to study the development of a helium nanoplasma up to the nanosecond timescale. Electrons, bound by the deep confining mean-field potential, are elevated toward the vacuum level in the nanoplasma expansion. Subsequent electron recombination gives rise to transitions between He^{+} states, resulting in autoionization. The time-resolved analysis of the energy transfer to quasifree electrons reveals a transient depletion of the Auger emission, which allows for a temporal gate to map the distribution of delocalized electrons in the developing mean field. Furthermore, we trace the recombination of delocalized electrons near the vacuum level into highly excited Rydberg states. Transient above-threshold ionization is introduced as a diagnostic tool to resolve the dynamics. Thus, the development of the electron distribution in the nanoplasma mean-field potential can be monitored via the features observed in the emission spectra.

Auger emission from the Coulomb explosion of helium nanoplasmas.

The long-time correlated decay dynamics of strong-field exposed helium nanodroplets is studied by means of photoelectron spectroscopy. As a result of the adiabatic expansion of the laser-produced, fully inner-ionized nanoplasma, delocalized electrons in the deep confining mean field potential are shifted towards the vacuum level. Meanwhile, part of the electrons localize in bound levels of the helium ions. The simple hydrogenlike electronic structure of He+ results in clear signatures in the experimentally observed photoelectron spectra, which can be traced back to bound-free and bound-bound transitions. Auger electron emission takes place as a result of the transfer of transition energy to weakly bound electrons in the quasifree electron band. Hence, the spatial and temporal development of the nanoplasma cloud is encoded in the experimental spectra, whereas the electronic properties of He+ help resolve the different contributions.

Highly Charged Rydberg Ions from the Coulomb Explosion of Clusters.

Ion emission from a nanoplasma produced in the interaction of intense optical laser pulses with argon clusters is studied resolving simultaneously charge states and recoil energies. By applying appropriate static electric fields we observe that a significant fraction of the ions Ar^{q+} (q=1-7) has electrons with binding energies lower than 150 meV; i.e., n_{Ryd}≥15 levels are populated. Charge state changes observed on a µs time scale can be attributed to electron emission due to autoionizing Rydberg states, indicating that high-ℓ Rydberg levels are populated as well. The experiments support theoretical predictions that a significant fraction of delocalized electrons, which are bound with hundreds of eV to the nanoplasma after the laser exposure, fill up meV bound ion states in the adiabatic expansion. We expect the process to be relevant for the long-term evolution of expanding laser-induced dense plasmas in general.

A sensitive EUV Schwarzschild microscope for plasma studies with sub-micrometer resolution.

We present an extreme ultraviolet (EUV) microscope using a Schwarzschild objective which is optimized for single-shot sub-micrometer imaging of laser-plasma targets. The microscope has been designed and constructed for imaging the scattering from an EUV-heated solid-density hydrogen jet. Imaging of a cryogenic hydrogen target was demonstrated using single pulses of the free-electron laser in Hamburg (FLASH) free-electron laser at a wavelength of 13.5 nm. In a single exposure, we observe a hydrogen jet with ice fragments with a spatial resolution in the sub-micrometer range. In situ EUV imaging is expected to enable novel experimental capabilities for warm dense matter studies of micrometer-sized samples in laser-plasma experiments.

Human C4orf14 interacts with the mitochondrial nucleoid and is involved in the biogenesis of the small mitochondrial ribosomal subunit.

The bacterial homologue of C4orf14, YqeH, has been linked to assembly of the small ribosomal subunit. Here, recombinant C4orf14 isolated from human cells, co-purified with the small, 28S subunit of the mitochondrial ribosome and the endogenous protein co-fractionated with the 28S subunit in sucrose gradients. Gene silencing of C4orf14 specifically affected components of the small subunit, leading to decreased protein synthesis in the organelle. The GTPase of C4orf14 was critical to its interaction with the 28S subunit, as was GTP. Therefore, we propose that C4orf14, with bound GTP, binds to components of the 28S subunit facilitating its assembly, and GTP hydrolysis acts as the release mechanism. C4orf14 was also found to be associated with human mitochondrial nucleoids, and C4orf14 gene silencing caused mitochondrial DNA depletion. In vitro C4orf14 is capable of binding to DNA. The association of C4orf14 with mitochondrial translation factors and the mitochondrial nucleoid suggests that the 28S subunit is assembled at the mitochondrial nucleoid, enabling the direct transfer of messenger RNA from the nucleoid to the ribosome in the organelle.

Actin and myosin contribute to mammalian mitochondrial DNA maintenance.

Mitochondrial DNA maintenance and segregation are dependent on the actin cytoskeleton in budding yeast. We found two cytoskeletal proteins among six proteins tightly associated with rat liver mitochondrial DNA: non-muscle myosin heavy chain IIA and ß-actin. In human cells, transient gene silencing of MYH9 (encoding non-muscle myosin heavy chain IIA), or the closely related MYH10 gene (encoding non-muscle myosin heavy chain IIB), altered the topology and increased the copy number of mitochondrial DNA; and the latter effect was enhanced when both genes were targeted simultaneously. In contrast, genetic ablation of non-muscle myosin IIB was associated with a 60% decrease in mitochondrial DNA copy number in mouse embryonic fibroblasts, compared to control cells. Gene silencing of ß-actin also affected mitochondrial DNA copy number and organization. Protease-protection experiments and iodixanol gradient analysis suggest some ß-actin and non-muscle myosin heavy chain IIA reside within human mitochondria and confirm that they are associated with mitochondrial DNA. Collectively, these results strongly implicate the actomyosin cytoskeleton in mammalian mitochondrial DNA maintenance.

[Cardiotropic characteristics of mildronat].

The paper summarizes the literature data and the authors' own investigations on cardiotropic and clinical-pharmacological properties of Mildronat. The medication normalizes energy metabolism, optimizes the functions of the heart, and improves the health state of patients with angina pectoris and cardiac insufficiency.

[The surgical restoration of the function of the knee joint in patients with severe refractory posttraumatic contractures]. / Khirurgicheskoe vosstanovlenie funktsii kolennogo sustava u bol'nykh s tiazhelymi zastarelymi posttravmaticheskimi kontrakturami.

Results of operative treatment of 100 patients with long-standing persistent contractures of the knee joint and partial defects of condyles of joint ends were studied. The treatment used allowed to obtain favorable results in majority of the patients and to return working ability to the patients. The application of perosseous apparatuses and allotransplantation make the potentialities of reconstructive surgery of the knee joint much wider.

[Significance of roentgenologic indications of osteogenesis in the choice of tactics in distraction osteosynthesis using G. A. Ilizarov's method in rigid pseudarthrosis]. / Znachenie rentgenologicheskikh proiavlenii kosteobrazovaniia dlia vybora taktiki distraktsionnogo osteosinteza po G. A. Ilizarovu pri tugikh lozhnykh sustavakh.

On the basis of 274 observations the authors stated the conception of staged roentgenologic course of the osseous tissue regeneration in case of close distraction of rigid false joints according to G. A. Ilizarov. In line with visual appraisal of roentgenograms there were used roentgenometry and densitometry. There are described in details the stages of reparative regeneration and in accordance with them are given the tactical recommendation as to the selection of the distraction rate and its duration, the terms of loading and immobilization of fractures by means of perosseous apparatus. The tactics of the patient control with regard to the peculiarities of osteogenesis in the process of distraction allowed to decrease the number of failures in treatment of false joints by 2 times.

[Mechanism of the effect of dibasol on the contractile and electric activities of the smooth muscle of the portal vein]. / Issledovanie mekhanizma deistviia dibazola na sokratite'lnuiu i élektricheskuiu aktivnos't gladkoi myshtsy vorotnoi veny.

The effects of dibasol on spontaneous electrical and contractile activities as well as on the reactions evoked by hyperkalemic solution and noradrenaline were studied in smooth muscle of rabbit portal vein. It was shown that dibasol blocked the potential-operated influx Ca2+ into smooth muscle cells. The noninactivating calcium channels were found to be more sensitive to dibasol than inactivating ones. Significant part of the tonic contraction induced by noradrenaline was resistant to dibasol suggesting its weak effect on Ca2+ influx through calcium channels operated by alpha 1-adrenoceptors. It is supposed that vasodilative effect of dibasol is associated with blocking the influx Ca2+ through potential-operated noninactivating calcium channels into smooth muscle cells.

[Rehabilitative treatment in old and inveterate fracture-dislocations of the bones of the feet]. / Vosstanovitel'noe lechenie nesvezhikh i zastarelykh perelomovyvikhov kostei stop.

The authors present the dynamics of the clinico-roentgenologic and biomechanical results of the treatment of 57 patients with late and inveterate dislocation fractures of the bones of the foot using the method of distraction. The analysis of the economic damage has demonstrated that a continuous disturbance in the working ability of the patients with this pathology causes an economic damage to the state averaging 7043.3 +/- 259.2 rubles. The favourable anatomic and functional results obtained in the absolute majority of the patients testify to the effectiveness of the method of distraction treatment.

[Electrophysiological research on the coupling of excitation-contraction during alpha-adrenoreceptor activation in blood vessel smooth muscles]. / Elektrofiziologicheskie issledovaniia sopriazheniia vozbuzhdeniia-sokrashcheniia pri aktivatsii al'fa-adrenoretseptorov v gladkikh myshtsakh krovenosnykh sosudov.

Alpha 1-adrenoceptor blocker--prazosin--was found to inhibit noradrenaline-induced depolarization and concentration in the smooth muscles of the portal rabbit vein, indicating that this reaction was due to alpha 1-adrenoceptor activation. In the pulmonary artery both alpha 1 and alpha 2-adrenoceptors appear to be involved in noradrenaline excitatory action, as the effect was not completely inhibited by prazosin. The results suggest that hypotensive action of prazosin is related to the cessation of Ca2+ ion influx through alpha 1-operated calcium channels. The decrease in Ca2+ influx through voltage-dependent calcium channels due to prazosin-evoked elimination of depolarization can also contribute to this effect.