Lunar Reconnaissance Orbiter Camera (LROC) Instrument Overview

The Lunar Reconnaissance Orbiter Camera (LROC) Wide Angle Camera (WAC) and Narrow Angle Cameras (NACs) are on the NASA Lunar Reconnaissance Orbiter (LRO). The WAC is a 7-color push-frame camera (100 and 400 m/pixel visible and UV, respectively), while the two NACs are monochrome narrow-angle linescan imagers (0.5 m/pixel). The primary mission of LRO is to obtain measurements of the Moon that will enable future lunar human exploration. The overarching goals of the LROC investigation include landing site identification and certification, mapping of permanently polar shadowed and sunlit regions, meter-scale mapping of polar regions, global multispectral imaging, a global morphology base map, characterization of regolith properties, and determination of current impact hazards.     

Tumor suppressor function of Betaig-h3 gene in radiation carcinogenesis.

Interaction between cell and extracellular matrix (ECM) plays a crucial role in tumor invasiveness and metastasis. Using an immortalized human bronchial epithelial (BEP2D) cell model, we showed previously that expression of a list of genes including Betaig-h3 (induced by transforming growth factor-beta), DCC (deleted in colorectal cancer), p21(cipl), c-fos, Heat shock protein (HSP27) and cytokeratin 14 were differentially expressed in several independently generated, radiation-induced tumor cell lines (TL1-TL5) relative to parental BEP2D cells. Our previous data further demonstrated that loss of tumor suppressor gene(s) as a likely mechanism of radiation carcinogenesis. In the present study, we chose Betaig-h3 and DCC that were downregulated in tumorigenic cells for further study. Restored expression of Betaig-h3 gene, not DCC gene, by transfecting cDNA into tumor cells resulted in a significant reduction in tumor growth. While integrin receptor alpha 5 beta 1 was overexpressed in tumor cells, its expression was corrected to the level found in control BEP2D cells after Betaig-h3 transfection. These data suggest that Betaig-h3 gene is involved in tumor progression by regulating integrin alpha 5 beta 1 receptor. Furthermore, exogenous TGF- beta 1 induced expression of Betaig-h3 gene and inhibited the growth of both control and tumorigenic BEP2D cells. Therefore, downregulation of Betaig-h3 gene may results from the decreased expression of upstream mediators such as TGF-beta. The findings provide strong evidence that the Betaig-h3 gene has tumor suppressor function in radiation-induced tumorigenic human bronchial epithelial cells and suggest a potential target for interventional therapy.     

Some statistical properties of transequatorial loops

Yohkoh soft X-ray telescope brought plenty of high quality images, it provides a good chance to research coronal loops, especially for transequatorial loops (TLs). In this paper, we focus on the statistical results of TLs including static properties and dynamic properties.

There are two types of classification about TLs: according to configuration and according to magnetic polarities of footpoints, respectively. The footpoints of TLs never root in sunspot, in a general way, they exist in moderately strong field. The mean separation value of TLs is close to 30° and the separation value varies with solar cycle. The helicity patterns of active regions connected by TLs are discussed, the mean twist value of TLs is close to zero. The formation of TLs is generally thought to be caused by magnetic reconnection, the relationship of TLs eruption with flare and CME is introduced.     

Medical prevention of space motion sickness--animal model of therapeutic effect of a new medicine on motion sickness.

Space motion sickness (MS) is one of the most important problems in the field of space medicine. In order to prevent space MS, a new medicine, PMPA, has been prepared by means of synthesizing in our laboratory. The purposes of this study were to set up animal models of PMPA against MS, and to observe its effects on anti-MS, and to prove its function of antagonism to choline. Eight cats, forty rabbits and two hundred and ten rats were selected as animal subjects. The parallel swing stimulus, a method causing the reversal syndromes and tests of anti-choline function were used in our experiments. The results are as follows: (1) The score of MS symptoms in cats with PMPA or scopolamine (SCOP) is significantly lower than that in cats with placebo (p<0.01), while the incidences of efficiency and prevention of PMPA (87.5%, 75%) are higher than those of SCOP (75.0%, 50%) in cats. (2) PMPA of 1.6 mg/kg or 0.8 mg/kg could antagonize the reversal syndromes and repress reversal rotation significantly in rabbits like SCOP in comparison with placebo (p<0.01). (3) PMPA could inhibit tremor evoked by oxotremorine or by nicotine-procaine in rats like SCOP, and play an important role in the antagonism to central M-choline and N-choline receptors. The animal experiments demonstrate that PMPA is an effective medicine against MS with antagonism function to choline.     

Particle acceleration and gamma rays in solar flares: Recent observations and new modeling

Experiments on SMM, GAMMA, Yohkoh, GRANAT, Compton GRO, INTEGRAL, RHESSI and CORONAS-F satellites over the past three decades have provided copious data for fundamental research relating to particle acceleration, transport and energetics of flares and to the ambient abundance of the solar corona, chromosphere and photosphere. We summarize main results of solar gamma-astronomy (including some results of several joint Russian–Chinese projects) and try to appraise critically a real contribution of those results into modern understanding of solar flares, particle acceleration at the Sun and some properties of the solar atmosphere. Recent findings based on the RHESSI, INTEGRAL and CORONAS-F measurements (source locations, spectrum peculiarities, ³He abundance etc.) are especially discussed. Some unusual features of extreme solar events (e.g., 28 October 2003 and 20 January 2005) have been found in gamma-ray production and generation of relativistic particles (solar cosmic rays, or SCR). A number of different plausible assumptions are considered concerning the details of underlying physical processes during large flares: (1) existence of a steeper distribution of surrounding medium density as compared to a standard astrophysical model (HSRA) for the solar atmosphere; (2) enhanced content of the ³He isotope; (3) formation of magnetic trap with specific properties; (4) prevailing non-uniform (e.g., fan-like) velocity (angular) distributions of secondary neutrons, etc. It is emphasized that real progress in this field may be achieved only by combination of gamma-ray data in different energy ranges with multi-wave and energetic particle observations during the same event. We especially note several promising lines for the further studies: (1) resonant acceleration of the ³He ions in the corona; (2) timing of the flare evolution by gamma-ray fluxes in energy range above 90 MeV; (3) separation of gamma-ray fluxes from different sources at/near the Sun (e.g., different acceleration sources/episodes during the same flare, contribution of energetic particles accelerated by the CME-driven shocks etc.); (4) asymmetric magnetic geometry and new magnetic topology models of the near-limb flares; (5) modeling of self-consistent time scenario of the event.     

An exit cavity was crucial to the polymerase activity of the early ribosome

The emergence of an RNA entity capable of synthesizing peptides was a key prebiotic development. It is hypothesized that a precursor of the modern ribosomal exit tunnel was associated with this RNA entity (e.g., "protoribosome" or "bonding entity") from the earliest time and played an essential role. Various compounds that can bind and activate amino acids, including extremely short RNA chains carrying amino acids, and possibly di- or tripeptides, would have associated with the internal cavity of the protoribosome. This cavity hosts the site for peptide bond formation and adjacent to it a relatively elongated feature that could have evolved to the modern ribosomal exit tunnel, as it is wide enough to allow passage of an oligopeptide. When two of the compounds carrying amino acids or di- or tripeptides (to which we refer, for simplicity, as small aminoacylated RNAs) were in proximity within the heart of the protoribosome, a peptide bond could form spontaneously. The growing peptide would enter the nearby cavity and would not disrupt the attachment of the substrates to the protoribosome or interfere with the subsequent attachment of additional small aminoacylated RNAs. Additionally, the presence of the peptide in the cavity would increase the lifetime of the oligopeptide in the protoribosome. Thus, subsequent addition of another amino acid would be more likely than detachment from the protoribosome, and synthesis could continue. The early ability to synthesize peptides may have resulted in an abbreviated RNA World.     

HF multipath passive single site radio location

This paper considers the problem of passive geolocation for the case of HF multipath propagation. A new technique is developed for the estimation of interpath time delay applying the multiple signal classification (MUSIC) superresolution spectral estimation method. The technique samples the signals received by two spatially separated antennas to compute the normalized MUSIC cepstrum. The method is applied to experimental data in a preliminary proof-of-concept analysis     

S/WAVES: The Radio and Plasma Wave Investigation on the STEREO Mission

This paper introduces and describes the radio and plasma wave investigation on the STEREO Mission: STEREO/WAVES or S/WAVES. The S/WAVES instrument includes a suite of state-of-the-art experiments that provide comprehensive measurements of the three components of the fluctuating electric field from a fraction of a hertz up to 16 MHz, plus a single frequency channel near 30 MHz. The instrument has a direction finding or goniopolarimetry capability to perform 3D localization and tracking of radio emissions associated with streams of energetic electrons and shock waves associated with Coronal Mass Ejections (CMEs). The scientific objectives include: (i) remote observation and measurement of radio waves excited by energetic particles throughout the 3D heliosphere that are associated with the CMEs and with solar flare phenomena, and (ii) in-situ measurement of the properties of CMEs and interplanetary shocks, such as their electron density and temperature and the associated plasma waves near 1 Astronomical Unit (AU). Two companion papers provide details on specific aspects of the S/WAVES instrument, namely the electric antenna system (Bale et al., Space Sci. Rev., 2007) and the direction finding technique (Cecconi et al., Space Sci. Rev., 2007).     

SMESE: A SMall Explorer for Solar Eruptions

The SMall Explorer for Solar Eruptions (SMESE) mission is a microsatellite proposed by France and China. The payload of SMESE consists of three packages: LYOT (a Lyman imager and a Lyman coronagraph), DESIR (an Infra-Red Telescope working at 35–80 and 100–250 μm), and HEBS (a High-Energy Burst Spectrometer working in X- and γ-rays).

The status of research on flares and coronal mass ejections is briefly reviewed in the context of on-going missions such as SOHO, TRACE and RHESSI. The scientific objectives and the profile of the mission are described. With a launch around 2012–2013, SMESE will provide a unique tool for detecting and understanding eruptions (flares and coronal mass ejections) close to the maximum phase of activity.