[Genetic Cell Reprogramming: A New Technology for Basic Research and Applied Usage].

Gene function disclosure and the development of modern technologies of genetic manipulations offered the possibility of genetic reprogramming application to alter cell specialization. With the involvement of a gene set that encodes the transcription factors responsible for the pluripotent state, any cell of an adult body could be reprogrammed into the embryonal.state and pluripotency could be induced in this cell. Such reprogrammed cells were called induced pluripotent stem cells (iPSCs), and they are capable of again passing through all developmental stages. This provides new possibilities for studies of the basic mechanisms of developmental biology, the formation of specific cell types, and the whole body. In culture, iPSCs could be maintained permanently in a nontransformed state and permit genetic manipulations while maintaining their pluripotent properties. Such a unique combination of their properties makes them an attractive tool for studies of various pathologies and for the delineation of treatment approaches. This review discusses the basic and applied aspects of iPSCs biology.

Spin torque, tunnel-current spin polarization, and magnetoresistance in MgO magnetic tunnel junctions.

We employ the spin-torque response of magnetic tunnel junctions with ultrathin MgO tunnel barrier layers to investigate the relationship between spin transfer and tunnel magnetoresistance (TMR) under finite bias, and find that the spin torque per unit current exerted on the free layer decreases by < 10% over a bias range where the TMR decreases by > 40%. This is inconsistent with free-electron-like spin-polarized tunneling and reduced-surface-magnetism models of the TMR bias dependence, but is consistent with magnetic-state-dependent decay lengths in the tunnel barrier.

Time-domain measurements of nanomagnet dynamics driven by spin-transfer torques.

We present time-resolved measurements of gigahertz-scale magnetic dynamics caused by torque from a spin-polarized current. By working in the time domain, we determined the motion of the magnetic moment throughout the process of spin-transfer-driven switching, and we measured turn-on times of steady-state precessional modes. Time-resolved studies of magnetic relaxation allow for the direct measurement of magnetic damping in a nanomagnet and prove that this damping can be controlled electrically using spin-polarized currents.

Temperature dependence of spin-transfer-induced switching of nanomagnets.

We measure the temperature, magnetic-field, and current dependence for the switching of nanomagnets by a spin-polarized current. Depending on current bias, switching can occur between either two static magnetic states or a static state and a current-driven precessional mode. In both cases, the switching is thermally activated and governed by the sample temperature, not a higher effective magnetic temperature. The activation barriers for switching between static states depend linearly on current, with a weaker dependence for dynamic to static switching.

Current-induced nanomagnet dynamics for magnetic fields perpendicular to the sample plane.

We present electrical measurements of high-frequency magnetic dynamics excited by spin-polarized currents in Co/Cu/Ni(80)Fe20 nanopillar devices, with a magnetic field applied perpendicular to the sample layers. As a function of current and magnetic field, the dynamical phase diagram contains several distinguishable precessional modes and also static magnetic states. Using detailed comparisons with numerical simulations, we provide rigorous tests of the theory of spin-transfer torques.

Microwave oscillations of a nanomagnet driven by a spin-polarized current.

The recent discovery that a spin-polarized electrical current can apply a large torque to a ferromagnet, through direct transfer of spin angular momentum, offers the possibility of manipulating magnetic-device elements without applying cumbersome magnetic fields. However, a central question remains unresolved: what type of magnetic motions can be generated by this torque? Theory predicts that spin transfer may be able to drive a nanomagnet into types of oscillatory magnetic modes not attainable with magnetic fields alone, but existing measurement techniques have provided only indirect evidence for dynamical states. The nature of the possible motions has not been determined. Here we demonstrate a technique that allows direct electrical measurements of microwave-frequency dynamics in individual nanomagnets, propelled by a d.c. spin-polarized current. We show that spin transfer can produce several different types of magnetic excitation. Although there is no mechanical motion, a simple magnetic-multilayer structure acts like a nanoscale motor; it converts energy from a d.c. electrical current into high-frequency magnetic rotations that might be applied in new devices including microwave sources and resonators.

Hydrogen atoms in impurity-helium solids.

Electron spin resonance (ESR) is employed to study atomic impurities (H and D) stabilized in impurity-helium (Im-He) solids at 1.35-1.5 K. The kinetics of the low temperature tunneling exchange reactions (D+H2-->H+HD, D+HD-->H+D2) are investigated in Im-He samples containing several different mixtures of hydrogen and deuterium impurities. The ESR line structures help determine the local environment of atoms trapped in Im-He solids. High concentrations of atomic hydrogen stored in Im-He solids may ultimately find applications in energy storage, matrix-isolation spectroscopy, and studies of different quantum statistical effects.

Laparoscopy in surgical treatment of vaginal aplasia: laparoscopy-assisted colpopoiesis and perineal hysterectomy with colpopoiesis.

OBJECTIVE: To optimize methods of surgery in patients with malformations of the genitalia. METHODS: Comparative evaluation of effectiveness of reconstructive plastic operations for malformations of uterus and vagina, performed by conventional methods or via laparoscopy. RESULTS: Laparoscopy permits identification of the pelvic peritoneum plus opening it and using the most mobile portion to create the vaginal fornix. In patients with vaginal and cervical aplasia and non-communicating functional rudimentary uterus, laparoscopy assists hysterectomy performed by the vaginal approach, as well as the last step of colpopoiesis. CONCLUSIONS: Laparoscopy significantly facilitates the procedure, reduces operating time and risks, and makes the operation available to the wide range of surgeons skilled in laparoscopy.

[The surgical treatment of patients with uterine myoma by using endoscopic methods and laser technics]. / Khirurgicheskoe lechenie bol'nykh miomoi matki s ispol'zovaniem éndoskopicheskikh metodov i lazernoi tekhniki.

The advantages and shortcomings of endoscopic and laser myomectomies in comparison with conventional myomectomy using laparotomy are discussed. A total of 279 patients with uterine myoma were subjected to myomectomy using laparotomy with CO2 laser (n = 109), laparotomy without laser (n = 45), laparoscopy (n = 120), and hysteroscopic removal of submucosal fibroids (n = 5). Comparative statistic analysis of the major intraoperative and early postoperative clinical parameters indicated that laparoscopic myomectomies are associated with an appreciable reduction of blood loss, its duration is the same as that of traditional operation, and the postoperative period runs a more benign course than after conventional surgery.

[The role of comprehensive examination and laparoscopy in the surgical treatment of tubal pregnancy]. / Rol' kompleksnogo obsledovaniia i laparoskopii v khirurgicheskom lechenii trubnoi beremennosti.

A total of 253 patients were examined and operated on for ectopic pregnancy. Eight-six patients were operated on through a laparoscopic access (group 1) and 167 through a laparotomic access (group 2). The authors assess the diagnostic value of echography, measurement of b-subunit of chorionic gonadotrophin, puncture of the abdominal cavity through the posterior vaginal vault, and of histologic examination of scrapings off the endometrium in a complex of examinations of patients with ectopic pregnancy. The results demonstrated the advantages of the laparoscopic access over laparotomy as involving lesser bleeding to the abdominal cavity and no evident adhesions.

[Expression of the vif gene of human immunodeficiency virus type 1 in Escherichia coli and study of the immunoreactivity of the vif protein]. / Ekspressiia gena vif virusa immunodefitsita cheloveka tipa 1 v kletkakhEscherichia coli i issledovanie immunoreaktivnosti vif-belka.

Full-sized gen vif of human immunodeficiency virus has been synthesized and cloned into plasmid pGEX-2T. Vif-gene expression was found in Escherichia coli cells resulting in production of a hybrid GST-protein. The recombinant protein studied by the immunoblotting technique reacted with 8 of 22 probes of human HIV-positive sera. The recombinant protein is specifically cut by thrombin in two proteins corresponding to GST and VIF-proteins in molecular mass.

[Surgical treatment of disseminated forms of external genital endometriosis using CO2 laser]. / Khirurgicheskoe lechenie rasprostranennykh form naruzhnogo genital'nogo éndometrioza s pomoshch'iu CO2-lazera.

CO2 laser surgery has been performed in 56 patients with external endometriosis which had Stage III-IV dissemination according to the AFS classification (1979). A control group included 20 patients who were operated without using CO2 laser. Analysis of the major operative parameters, such as operation duration, blood loss, length of the postoperative period, febrile response, incidence of postoperative relapses suggested that the use of the laser technically facilitated surgery in patients with disseminated endometriosis, shortened the operation and was associated with a smaller intraoperative blood loss, better postoperative course, more reliable asepsis and ablastics and lower incidence of relapses.

[Experience with the use of the CO2 laser in reconstructive and plastic gynecologic surgery in patients with uterine myoma and endometriosis]. / Opyt ispol'zovaniia CO2-lazera pri rekonstruktivnopla sticheskikh operatsiiakh u bol'nykh miomoi matki i endometriozom.

CO2 laser has been used during reconstructive plastic surgery for uterine myoma, endometriosis of various locations, and associated gynecologic conditions in 71 patients. Comparison in patients with uterine myoma who underwent conservative myomectomy with and without the use of CO2 laser showed that treatment with CO2 laser diminished blood loss and duration of the operation, and improved postoperative progress.