Physical Startup of the TWAC Storage Ring

C⁶⁺ ions with energy 200 MeV/nucleon have been accumulated in the chamber of the ring magnet of the U-10 proton synchrotron used as a storage ring in the TWAC setup. A C⁴⁺ ion beam from the laser source was first accelerated in the I-3 injector up to 1.3 MeV/nucleon and in the UK booster synchrotron up to final energy with periodicity 3.5 sec. Ions have been accumulated in U-10 using the multiple charge-exchange injection scheme C⁴⁺ C⁶⁺. An increase in the ion intensity in the accumulator has been observed during several injection cycles. Experimental data on the attained parameters of the accumulated beam are presented, and the status of the optimization of the accumulation regime is discussed.     

Blood flow dynamics in different layers of the somatosensory region of the cerebral cortex on the rat during mechanical stimulation of the vibrissae

Since the creation of the Office of Alternative Medicine (OAM) at the National Institutes of Health (NIH), progress has been made in the evaluation and, where appropriate, the clinical and scientific acceptance of "complementary and alternative" medicine (CAM). This progress is due in part to initiatives jointly conducted by the NIH and the U.S. Food and Drug Administration (FDA). In particular, advances in the evaluation and acceptance of two CAM practices, acupuncture and botanical medicine, have resulted from ongoing cooperation between the two agencies. The legalization of the use of acupuncture needles in 1996 came as a result of a workshop sponsored by the OAM with the participation of the FDA, which explored key regulatory issues. Prompted by similar regulatory issues, as well as by the initiation of NIH-funded research projects, the OAM sponsored an international symposium to examine the evidence for and the role of botanical medicine in the United States. This conference generated a series of workshops sponsored by the Drug Information Association in conjunction with NIH and FDA, which explored the scientific, regulatory, and policy issues of heterogeneous botanical products. These efforts resulted in the initiation of a large randomized multicenter clinical trial (sponsored by the National Institute of Mental Health) of the botanical, St. John's wort, for the treatment of depression, and the formation of internal working groups within the FDA that are drafting a guidance policy for the development of botanicals as drugs in the United States. This document is expected to be available in the near future.     

The protective reaction of the myocardium to ischemic damage

The morphological and functional consequences of epinephrine-induced myocardial infarction were studied in normo- (Wistar) and hypertensive (ISIAH) rats. After experimental myocardial infarction there was an irreversible transition to the "worn-out" stage or "plastic damage" to the myocardium. Thus, myocardial hibernation in ISIAH rats anticipates and determines the development of myocardial stunning, i.e., irreversible myocardial damage, whereas in the normotensive animals, the protective effect of hibernation is fully shown. The ontogenetic features of myocardial response of ISIAH rats to hypoxia promote transformation of adaptive hibernation and stunning to maladaptive pathological changes causing hypoxic alterations.     

Characteristics of HMX combustion waves at various pressures and initial temperatures

Temperature profiles and combustion-wave parameters are obtained experimentally for combustion of pressed HMX at room temperature and pressures of 1–500 atm and in the case of a change in the initial temperature of the specimens from −170 to +100°C at pressures of 1–75 (90) atm. The following combustion-zone parameters are determined: the heat effect in the c-phase, the heat transfer from the gas to the c-phase by thermal conduction and radiation, the rate of heat release in the gas near the surface, and the dimensions and temperature of the combustion zones. The authorsé previous conclusion that there is one process of decomposition and evaporation of HMX during its gasification in the condensed-phase reaction layer of the combustion wave is confirmed. Dependences of the fraction of decomposed HMX on the initial temperature of the specimens and the pressure are obtained. The differential characteristics of the combustion rate, surface temperature, and radiative heat transfer, required for the nonlinear theory of HMX combustion stability, are evaluated. Translated fromFizika Goreniya i Vzryva, Vol. 34, No. 2, pp. 59–66, March–April, 1998.     

Investigation of nuclear-reactor friction units operating in heavy high-temperature liquid-metal heat carriers. Part 1. Experimental equipment

Experimental equipment designed for solving tribological problems arising in friction units operating in heavy liquid-metal heat carriers for nuclear-reactor circuits is discussed. In order to study fretting corrosion, a setup has been produced that simulates the wear of a fuel element in contact with a spacer grid cell. Thus, the vibration strength of the steam generator of a fast-neutron reactor with a lead heat carrier is substantiated. An experimental setup for studying and carrying out endurance testing of cylindrical gears with standard circuit and plain bearings operating in fast-neutron reactors in the medium of a lead heat carrier is described. Experimental specimens of circulation pumps for reactor equipment are developed for investigation of the wear of steel and cast-iron plain bearings operating in lead medium and the wear of eutectic lead-bismuth and lead-lithium alloys.     

Retinoic acid disrupts anterior ectodermal and endodermal development in ascidian larvae and postlarvae

In vertebrates, excess all-trans retinoic acid (RA) applied during axis formation leads to the apparent truncation of anterior structures. In this study we sought to determine the type of defects caused by ectopic RA on the development of the ascidian Herdmania curvata. We demonstrate that H. curvata embryos cultured in the presence of RA develop into larvae whose trunks are shortened and superficially resemble those of early metamorphosing postlarvae. Despite RA-treated larvae lacking papillar structures they respond normally to natural cues that induce metamorphosis, indicating that chemosensory functionality previously mapped to the most anterior region of normal larvae is unaffected by RA. Excess RA applied during postlarval development leads to a graded loss of the juvenile pharynx, apparently by respecifying anterior endoderm to a more posterior fate. This structure is considered homologous to the gill slits of amphioxus, which are also lost upon RA treatment. This suggests that RA may have had a role in the development of the pharynx of the ancestral chordate and that this function has been maintained in ascidians and cephalochordates and lost in vertebrates.     

The lateral septal nucleus: its morphological and functional organization and its role in the formation of chronorhythms

The lateral septal nucleus (LSN) is the largest septal nucleus and occupies one of the most strategically important positions in the forebrain, connecting the structures of the limbic system with different sites of the brain stem. Such a situation obliges LSN not only to participate in the regulation, but also to implement overall coordination and modulation of various visceral and somatic functions. The review deals with the general characteristic of the septal complex, the functional morphology, pre- and postnatal ontogenesis, afferent and efferent connections, mediator and modulator nature of LSN fibers. Special attention is paid to the participation of LSN in the neuroendocrine regulation of the sexual system. On the basis of literature and our own experimental findings it is shown that the LSN is a chronoregulatory structure which is responsible for the biorhythmologic organization of the functions of the mammalian organism.