bluuebunny/crossref_metadata_2025 huggingface dataset:
Disk-halo interactions: molecular clouds in the Galactic center
Authors: Riquelme D. , Martín-Pintado J. , Mauersberger R. , Martín S. , Bronfman L.
Published: May 2014

We study the disk-halo interaction, in the context of orbits and Giant Molecular loops (GMLs) in the Galactic center (GC) region. From a large scale survey of the central kpc of the Galaxy, in SiO J = (2 − 1), HCO+J = (1 − 0) and H13CO+J = (1 − 0) molecular emission, we identify shock regions traced by the enhancement of the SiO. These positions were studied using the 12C/13C isotopic ratio to trace gas accretion/ejection. We found a systematically higher 12C/13C isotopic ratio (> 40) toward the GMLs and the x1 orbits than for the GC standard molecular clouds (20–25). The high isotopic ratios are consistent with the accretion of the gas from the halo and from the outskirts of the Galactic disk. From multi-transitional observations of NH3, we derive two kinetic temperature regimes (one warm at ∼150 K and one cold at ∼40 K) for all the positions, except for the GMLs positions where only the warm component is present. The fractional abundances derived from the different molecules support the shock origin for the heating mechanism in the GC. We also present a detailed study of one molecular cloud placed in the foot points of two giant molecular loops, where two of the previously selected positions are placed. Using the 22m Mopra telescope we mapped the molecular cloud M − 3.8 + 0.9 in 3-mm molecular lines. The data show structures at small scale in SiO emission, with narrower line profiles than those of, e.g, HCO+ or HCN, which indicate that the shocks are dynamically confined. The data also show clear differences between different molecular tracers, e.g., between the SiO and HCO+ emission, which would indicate differences in the physical properties and chemistry within the cloud.
SMA observations towards massive clouds in the central molecular zone
Authors: Lu Xing , Zhang Qizhou , Kauffmann Jens , Pillai Thushara
Published: May 2014

Recently we conducted a mini-survey towards a sample of six massive clouds with surface density >1024 cm−2 in the central molecular zone (CMZ) of the Milky Way, with the SMA at 280 GHz in the compact array and at 230 GHz in the compact/subcompact arrays. The data reveal compact dust continuum peaks, some of which are also associated with organic molecular lines and thermal SiO emission. The subcompact array data helps recover more structures, e.g. the regularly spaced, well-aligned continuum fragments in the 20 km s−1 cloud. Shock tracers such as SiO are found in all the clouds. Our observations suggest potential protostellar origin for some of the dust continuum peaks in these regions.
Large–scale and high–sensitivity multi–line CO surveys toward the Galactic center
Authors: Enokiya R. , Torii K. , Schultheis M. , Asahina Y. , Matsumoto R. , Yamamoto H. , Tachihara K. , Okuda T. , Morris M. R. , Fukui Y.
Published: May 2014

We carried out large–scale (4 × 2 degree) CO multi–line observations toward the central molecular zone (CMZ) in the Galactic center (GC) with the NANTEN2 4m telescope and mapped several diffuse molecular features located at relatively high Galactic latitudes above 0°.6. These high–latitude features are composed of diffuse molecular halo gas and molecular filaments according to their morphological aspects. Their high velocities and high intensity ratios between 12CO J = (2−1) and J = (1−0) clearly indicate their location in the GC, and their total mass amount to ∼10% of that of the CMZ. We discuss that magnetic field is a possible mechanism of these high–latitude molecular features lifting up toward high galactic latitude.
All quiet on the Western front? New evidence for massive star formation in Sgr C
Authors: Kendrew Sarah , Ginsburg Adam , Johnston Katharine , Beuther Henrik , Bally John , Cyganowski Claudia J. , Battersby Cara
Published: May 2014

We summarize here our recent findings from near-infrared spectroscopy and 1 mm line and continuum observations of a recently identified extended green object (EGO) in Sgr C, whose observational characteristics suggest early-stage massive star formation is taking place. Located on the outskirts of the massive evolved Hii region associated with Sgr C in the Western central molecular zone (CMZ), the EGO measures ∼10″ (0.4 pc at 8.5 kpc). We confirm that early-stage star formation is taking place on the periphery of the Sgr C Hii region. The data show clear detections of two protostellar cores and several knots of H2 and Brackett γ emission alongside a previously detected compact radio source. We calculate the cores' joint mass to be ∼103 M⊙, with column densities of 1-2 × 1024 cm−2. The host molecular clouds mass is approximately 105 M⊙. Despite these favorable conditions, the cloud is curiously devoid of any further star formation, making it comparable to other remarkably quiescent clouds, such as G0.253 in the Eastern CMZ.
Structure of the nuclear stellar cluster of the Milky Way galaxy
Authors: Kunneriath Devaky , Schödel Rainer , Stolovy Susan , Feldmeier Anja
Published: May 2014

Nuclear star clusters are unambiguously detected in about 50–70% of spiral and spheroidal galaxies. They have typical half-light radii of 2–5 pc, dynamical mass ranging from 106 – 107 M⊙, are brighter than globular clusters, and obey similar scaling relations with host galaxies as supermassive black holes. The nuclear stellar cluster (NSC) which surrounds Sgr A*, the SMBH at the center of our galaxy, is the nearest nuclear cluster to us, and can be resolved to scales of milliparsecs. The strong and highly variable extinction towards the Galactic center makes it very hard to infer the intrinsic properties of the NSC (structure and size). We attempt a new way to infer its properties by using Spitzer MIR images in a wavelength range 3–8 μm where the extinction is at a minimum, and the NSC clearly stands out as a separate structure. We present results from our analysis, including extinction-corrected images and surface brightness profiles of the central few hundred parsecs of the Milky Way.
The nuclear cluster of the Milky Way: total mass and luminosity
Authors: Fritz T. K. , Chatzopoulos S. , Gerhard O. , Gillessen S. , Genzel R. , Pfuhl O. , Tacchella S. , Eisenhauer F. , Ott T.
Published: May 2014

Here we present the fundamental properties of the nuclear cluster of the Milky Way. First, we derive its structural properties by constructing a density map of the central 1000″ using extinction-corrected star counts. We can describe the data with a two-component model built from Sersic profiles. The inner nearly spherical component is the nuclear cluster. The outer, strongly flattened component can be identified with the stellar component of the circumnuclear zone. Second, we enlarge the radius inside which detailed dynamics are available from 1 pc to 4 pc. We use more than 10000 individual proper motions and more than 2700 radial velocities. We determine the cluster mass by means of isotropic spherical Jeans modeling. We get a nuclear cluster mass within 100″ of M100″=(6.11 ± 0.52|fix R0±0.97|R0) × 106 M⊙, which corresponds to a total cluster mass of MNC=(13.08 ± 2.51|fix R0± 2.08|R0) × 106 M⊙. By combination of our mass with the flux we calculate M/L=0.50 ± 0.12 M⊙/L⊙,Ks for the central 100″. That is broadly consistent with a Chabrier IMF. With its mass and a luminosity of MKs=−15.30±0.26 the nuclear cluster is a bright and massive specimen with a typical size.
Metallicity studies of the Galactic center: evidence for a top-heavy star formation history?
Authors: Najarro Francisco , de la Fuente Diego , Geballe Tom R. , Figer Don F.
Published: May 2014

The Galactic center (GC) region hosts three of the most massive resolved young clusters in the Local Group and constitutes a test bed for studying the star formation history of the region and inferring the possibility of a top-heavy scenario. Further, recent detection of a large number of apparently isolated massive stars within the inner 80 pc of the Galactic center has raised fundamental questions regarding massive star formation in a such a dense and harsh environment. Noting that most of the isolated massive stars have spectral analogs in the Quintuplet cluster, we have undertaken a combined analysis of the infrared spectra of both selected Quintuplet stars and the isolated objects using Gemini spectroscopy. We present preliminary results, aiming at α-elements versus iron abundances, stellar properties, ages and radial velocities which will differentiate the top-heavy and star-formation scenarios.
Observations of the gas cloud G2 in the Galactic center
Authors: Gillessen S. , Genzel R. , Fritz T. K. , Eisenhauer F. , Pfuhl O. , Ott T. , Burkert A. , Schartmann M. , Ballone A.
Published: May 2014

In 2011, we discovered a compact gas cloud (“G2”) with roughly three Earth masses that is falling on a near-radial orbit toward the massive black hole in the Galactic center. The orbit is well constrained and pericenter passage is predicted for early 2014. Our data beautifully show that G2 gets tidally sheared apart due to the massive black hole's force. During the next months, we expect that in addition to the tidal effects, hydrodynamics get important, when G2 collides with the hot ambient gas around Sgr A*. Simulations show that ultimately, the cloud's material might fall into the massive black hole. Predictions for the accretion rate and luminosity evolution, however, are very difficult due to the many unknowns. Nevertheless, this might be a unique opportunity in the next years to observe how gas feeds a massive black hole in a galactic nucleus.
The infrared K-band identification of the DSO/G2 source from VLT and Keck data
Authors: Eckart A. , Horrobin M. , Britzen S. , Zamaninasab M. , Mužić K. , Sabha N. , Shahzamanian B. , Yazici S. , Moser L. , García-Marin M. , Valencia-S. M. , Borkar A. , Bursa M. , Karssen G. , Karas V. , Zajaček M. , Bronfman L. , Finger R. , Jalali B. , Vitale M. , Rauch C. , Kunneriath D. , Moultaka J. , Straubmeier C. , Rashed Y. E. , Markakis K. , Zensus A.
Published: May 2014

A fast moving infrared excess source (G2) which is widely interpreted as a core-less gas and dust cloud approaches Sagittarius A* (Sgr A*) on a presumably elliptical orbit. VLT Ks-band and Keck K′-band data result in clear continuum identifications and proper motions of this ∼19m Dusty S-cluster Object (DSO). In 2002-2007 it is confused with the star S63, but free of confusion again since 2007. Its near-infrared (NIR) colors and a comparison to other sources in the field speak in favor of the DSO being an IR excess star with photospheric continuum emission at 2 microns than a core-less gas and dust cloud. We also find very compact L′-band emission (<0.1″) contrasted by the reported extended (0.03″ up to ∼0.2″ for the tail) Brγ emission. The presence of a star will change the expected accretion phenomena, since a stellar Roche lobe may retain a fraction of the material during and after the peri-bothron passage.
Long-term monitoring of Sgr A* at 7 mm with VERA and KaVA
Authors: Akiyama K. , Kino M. , Sohn B. , Lee S. , Trippe S. , Honma M.
Published: May 2014

We present the results of radio monitoring observations of Sgr A* at 7 mm (i.e. 43 GHz) with the VLBI Exploration of Radio Astrometry (VERA), which is a VLBI array in Japan. VERA provides angular resolution on millisecond scales, resolving structures within 100 Schwarzschild radii of Sgr A* , similar to the Very Large Baseline Array (VLBA). We performed multi-epoch observations of Sgr A* in 2005 - 2008, and started monitoring it again with VERA from 2013 January to trace the current G2 encounter event. Our preliminary results in 2013 show that Sgr A* on mas scales has been in an ordinary state as of August 2013, although some fraction of the G2 cloud already passed the pericenter of Sgr A* in April 2013. We will continue monitoring Sgr A* with VERA and the newly developed KaVA (KVN and VERA Array).
Event horizon scale emission models for Sagittarius A*
Authors: Dexter J.
Published: May 2014

Very long baseline interferometry observations at millimeter wavelengths have detected source structure in Sgr A* on event horizon scales. Near-infrared interferometry will achieve similar resolution in the next few years. These experiments provide an unprecedented opportunity to explore strong gravity around black holes, but interpreting the data requires physical modeling. I discuss the calculation of images, spectra, and light curves from relativistic MHD simulations of black hole accretion. The models provide an excellent description of current observations, and predict that we may be on the verge of detecting a black hole shadow, which would constitute the first direct evidence for the existence of black holes.
Flux monitoring observations of Sgr A* at 8 GHz and 2 GHz with the NICT Kashima–Koganei VLBI System
Authors: Takekawa S. , Oka T. , Sekido M.
Published: May 2014

We have been conducting flux monitoring observations of Sgr A* at 8 GHz and 2 GHz using the NICT Kashima-Koganei VLBI system (109 km baseline) since mid-February 2013. The primary objective of the monitoring is a search for flux variation which is expected to be caused by the interaction between the G2 cloud and the accretion disk. Until 2013 September 22, we observed Sgr A* for 39 days, five hours on each day. Four quasars (NRAO 530, PKS 1622–253, PKS 1622–297, PKS 1921–293) were also observed as flux calibrators every 6 minutes. No significant change nor variation has been detected in the 8 GHz flux density of Sgr A*. The 8 GHz flux density was 0.81 ± 0.07 Jy (preliminary), while no significant 2 GHz emission was detected by our system. We will continue monitoring as often as possible until at least 2014 May.
On the past activity of Sgr A*
Authors: Ponti G. , Morris M. R. , Clavel M. , Terrier R. , Goldwurm A. , Soldi S. , Sturm R. , Haberl F. , Nandra K.
Published: May 2014

Recent X-ray emission events in the Galactic center would be expected to generate an X-ray reflection response within the surrounding clouds of the central molecular zone, in the Galactic disk and even, if powerful enough, in clouds outside our Galaxy. We review here the current constraints on Sgr A*'s past activity obtained through this method, with particular emphasis on the strong evidence that has been gathered for multiple X-ray flashes during the past few hundred years.
Detection of a high brightness temperature radio core in the AGN-driven molecular outflow candidate NGC 1266
Authors: Nyland K. , Alatalo K. , Wrobel J. M. , Young L. M. , Morganti R. , Davis T. A. , de Zeeuw P. T. , Deustua S. , Bureau M.
Published: May 2014

We present new Karl G. Jansky Very Large Array (VLA) Hi absorption and Very Long Baseline Array (VLBA) continuum observations of the active galactic nucleus (AGN)-driven molecular outflow candidate NGC 1266. Although other well-known systems with molecular outflows may be driven by star formation in a central molecular disk, the molecular mass outflow rate reported in Alatalo et al. (2011) in NGC 1266 of 13 M⊙ year−1 exceeds star formation rate estimates from a variety of tracers. This suggests that an additional energy source, such as an AGN, may play a significant role in powering the outflow. Our high spatial resolution Hi absorption data reveal compact absorption against the radio continuum core co-located with the putative AGN, and the presence of a blueshifted spectral component re-affirms that gas is indeed flowing out of the system. Our VLBA observations at 1.65 GHz reveal one continuum source within the densest portion of the molecular gas, with a diameter d < 8 mas (1.2 pc), a radio power Prad = 1.48 × 1020 W Hz−1, and a brightness temperature Tb > 1.5 × 107 K that is most consistent with an AGN origin. The radio continuum energetics implied by the compact VLBA source, as well as archival VLA continuum observations at lower spatial resolution, further support the possibility that the AGN in NGC 1266 could be driving the molecular outflow. These findings suggest that even low-level AGNs, with supermassive black hole masses similar to Sgr A*, may be able to launch massive outflows in their host galaxies.
Fermi bubble simulations: black hole feedback in the Milky Way
Authors: Ruszkowski M. , Yang H.-Y. K. , Zweibel E.
Published: May 2014

The Fermi γ-ray telescope discovered a pair of bubbles at the Galactic center. These structures are spatially-correlated with the microwave emission detected by the WMAP and Planck satellites. These bubbles were likely inflated by a jet launched from the vicinity of a supermassive black hole in the Galactic center. Using MHD simulations, which self-consistently include interactions between cosmic rays and magnetic fields, we build models of the supersonic jet propagation, cosmic ray transport, and the magnetic field amplification within the Fermi bubbles. Our key findings are that: (1) the synthetic Fermi γ-ray and WMAP microwave spectra based on our simulations are consistent with the observations, suggesting that a single population of cosmic ray leptons may simultaneously explain the emission across a range of photon energies; (2) the model fits the observed centrally-peaked microwave emission if a second, more recent, pair of jets embedded in the Fermi bubbles is included in the model. This is consistent with the observationally-based suggestion made by Su & Finkbeiner (2012); (3) the radio emission from the bubbles is expected to be strongly polarized due to the relatively high level of field ordering caused by elongated turbulent vortices. This effect is caused by the interaction of the shocks driven by the jets with the preexisting interstellar medium turbulence; (4) a layer of enhanced rotation measure in the shock-compressed region could exist in the bubble vicinity but the level of this enhancement depends on the details of the magnetic topology.
Origin of nonthermal emission from the Fermi bubbles and mechanisms of particle acceleration there
Authors: Dogiel V. A. , Cheng K.-S. , Chernyshov D. O. , Ko C.-M.
Published: May 2014

The discovery of the two giant γ-ray lobes (Fermi bubbles) in the Galactic center (see Dobler et al. 2010 and Su et al. 2010) was one of the most impressive events of the last few years in astrophysics. However, some indications on giant structures in the Galactic center (GC) were observed several years before by WMAP in the radio frequency range between 23 and 33 MHz (Finkbeiner 2004), and by ROSAT in hard X-rays (Bland-Hawthorn & Cohen 2003). Recent observations performed by the Planck Collaboration (Ade et al. 2012) found also lobes in the microwave range which spatially coincided the Fermi bubbles that indicated on the common origin of these phenomena.
Dark matter and pulsar model constraints from Galactic center Fermi/LAT γ-ray observations
Authors: Gordon Chris , Macias Oscar
Published: May 2014

Employing Fermi/LAT γ-ray observations, several independent groups have found excess extended γ-ray emission at the Galactic center (GC). Both, annihilating dark matter (DM) or a population of ~ 103 unresolved millisecond pulsars (MSPs) are regarded as well motivated possible explanations. However, there is significant uncertainties in the diffuse Galactic background at the GC. We have performed a revaluation of these two models for the extended γ-ray source at the GC by accounting for the systematic uncertainties of the Galactic diffuse emission model. We also marginalize over point source and diffuse background parameters in the region of interest. We show that the excess emission is significantly more extended than a point source. We find that the DM (or pulsar population) signal is larger than the systematic errors and therefore proceed to determine the sectors of parameter space that provide an acceptable fit to the data. We found that a population of several thousand MSPs with parameters consistent with the average spectral shape of Fermi/LAT measured MSPs was able to fit the GC excess emission. For DM, we found that a pure τ+τ− annihilation channel is not a good fit to the data. But a mixture of τ+τ− and bb with a 〈σ v〉 of order the thermal relic value and a DM mass of around 20 to 60 GeV provides an adequate fit.
The cosmic ray ionization rate in the central parsec of the Galaxy
Authors: Goto Miwa
Published: May 2014

Cosmic rays represent a unique crossing point of high-energy astrophysics and astrochemistry. The cosmic ray ionization rate of molecular hydrogen (ζ2) measured by H3+ spectroscopy in the central parsec of the Galaxy is 2 orders of magnitude higher than that in the dense clouds outside the Galactic center. However, it is still too short, by the factor of 10,000, to agree with an extremely high ζ2 that accommodates the new γ-ray observations of Sgr A* and its environment.
The Galactic center pulsar SGR J1745–29
Authors: Bower Geoffrey C.
Published: May 2014

The discovery of the Galactic center pulsar SGR J1745–29 has provided an important new window into plasma processes in the Galactic center (GC) interstellar medium, the population of compact objects in the GC, and the prospects for probing general relativistic effects through timing of a Sgr A* pulsar companion. We discuss here radio observations of the pulsar and how they are providing fresh insights. In particular, our results show that recent pulsar surveys had the sensitivity to detect many pulsars in the GC region without significant losses due to interstellar scattering. This raise the question of why only this pulsar close to Sgr A* has been detected.
Radiatively inefficient accretion in short-period black hole low mass X-ray binaries
Authors: Connors Riley M. T.
Published: May 2014

There is statistical evidence for a dearth of short-period (Porb < 4h) black hole (BH) low mass X-ray binaries (LMXBs) in the Galaxy. At short periods accretion onto the central object (be it a BH) may become inefficient because the cooling timescale of the gas is greater than the accretion timescale (this is the well known ADAF model). The nature of the switch is important in terms of the outburst timescales of transient sources. The switch may be sharp or occur smoothly over time. I show that the dearth can be explained if the switch to inefficiency occurs sharply at some fraction of the Eddington luminosity of the BH (fLEdd).
Low frequency (74 MHz) radio continuum observations of the inner 13° × 7° of the Galactic center
Authors: Rickert M. , Yusef-Zadeh F. , Brogan C.
Published: May 2014

We analyze a high resolution (114″ × 60″) 74 MHz image of the Galactic center taken with the Very Large Array (VLA). We have identified several absorption and emission features in this region, and we discuss preliminary results of two Galactic center sources: the Sgr D complex (G1.1–0.1) and the Galactic center lobe (GCL).

The 74 MHz image displays the thermal and nonthermal components of Sgr D and we argue the Sgr D supernova remnant (SNR) is consistent with an interaction with a nearby molecular cloud and the location of the Sgr D Hii region on the near side of the Galactic center. The image also suggests that the emission from the eastern side of the GCL contains a mixture of both thermal and nonthermal sources, whereas the western side is primarily thermal.
Sec-containing TrxR1 is essential for self-sufficiency of cells by control of glucose-derived H2O2
Authors: Peng X , Mandal P K , Kaminskyy V O , Lindqvist A , Conrad M , Arnér E S J
Published: May 2014

It is commonly recognized that diabetic complications involve increased oxidative stress directly triggered by hyperglycemia. The most important cellular protective systems against such oxidative stress have yet remained unclear. Here we show that the selenoprotein thioredoxin reductase 1 (TrxR1), encoded by the Txnrd1 gene, is an essential enzyme for such protection. Individually grown Txnrd1 knockout (Txnrd1−/−) mouse embryonic fibroblasts (MEFs) underwent massive cell death directly linked to glucose-induced H2O2 production. This death and excessive H2O2 levels could be reverted by reconstituted expression of selenocysteine (Sec)-containing TrxR1, but not by expression of Sec-devoid variants of the enzyme. Our results show that Sec-containing TrxR1 is absolutely required for self-sufficient growth of MEFs under high-glucose conditions, owing to an essential importance of this enzyme for elimination of glucose-derived H2O2. To our knowledge, this is the first time a strict Sec-dependent function of TrxR1 has been identified as being essential for mammalian cells.
The heat-shock response co-inducer arimoclomol protects against retinal degeneration in rhodopsin retinitis pigmentosa
Authors: Parfitt D A , Aguila M , McCulley C H , Bevilacqua D , Mendes H F , Athanasiou D , Novoselov S S , Kanuga N , Munro P M , Coffey P J , Kalmar B , Greensmith L , Cheetham M E
Published: May 2014

Retinitis pigmentosa (RP) is a group of inherited diseases that cause blindness due to the progressive death of rod and cone photoreceptors in the retina. There are currently no effective treatments for RP. Inherited mutations in rhodopsin, the light-sensing protein of rod photoreceptor cells, are the most common cause of autosomal-dominant RP. The majority of mutations in rhodopsin, including the common P23H substitution, lead to protein misfolding, which is a feature in many neurodegenerative disorders. Previous studies have shown that upregulating molecular chaperone expression can delay disease progression in models of neurodegeneration. Here, we have explored the potential of the heat-shock protein co-inducer arimoclomol to ameliorate rhodopsin RP. In a cell model of P23H rod opsin RP, arimoclomol reduced P23H rod opsin aggregation and improved viability of mutant rhodopsin-expressing cells. In P23H rhodopsin transgenic rat models, pharmacological potentiation of the stress response with arimoclomol improved electroretinogram responses and prolonged photoreceptor survival, as assessed by measuring outer nuclear layer thickness in the retina. Furthermore, treated animal retinae showed improved photoreceptor outer segment structure and reduced rhodopsin aggregation compared with vehicle-treated controls. The heat-shock response (HSR) was activated in P23H retinae, and this was enhanced with arimoclomol treatment. Furthermore, the unfolded protein response (UPR), which is induced in P23H transgenic rats, was also enhanced in the retinae of arimoclomol-treated animals, suggesting that arimoclomol can potentiate the UPR as well as the HSR. These data suggest that pharmacological enhancement of cellular stress responses may be a potential treatment for rhodopsin RP and that arimoclomol could benefit diseases where ER stress is a factor.
SPAG5 upregulation predicts poor prognosis in cervical cancer patients and alters sensitivity to taxol treatment via the mTOR signaling pathway
Authors: Yuan L-J , Li J-D , Zhang L , Wang J-H , Wan T , Zhou Y , Tu H , Yun J-P , Luo R-Z , Jia W-H , Zheng M
Published: May 2014

Previously, we found that sperm-associated antigen 5 (SPAG5) was upregulated in pelvic lymph node metastasis–positive cervical cancer. The aim of this study is to examine the role of SPAG5 in the proliferation and tumorigenicity of cervical cancer and its clinical significance in tumor progression. In our study, SPAG5 expression in cervical cancer patients was detected using quantitative real-time polymerase chain reaction, western blotting, and immunohistochemistry; cervical cancer cell function with downregulated SPAG5 in vitro was explored using tetrazolium assay, flow cytometry, and colony formation and Transwell assays. SPAG5 was upregulated in tumor tissue compared with paired adjacent noncancerous tissues; SPAG5 upregulation in tumor tissues indicated poor disease-free survival, which was also an independent prognostic indicator for cervical cancer patients. In vitro study demonstrated that SPAG5 downregulation inhibited cell proliferation and growth significantly by G2/M arrest and induction of apoptosis, and hindered cell migration and invasion. Under SPAG5 downregulation, the sensitivity of cervical cancer cells differed according to taxol dose, which correlated with mammalian target of rapamycin (mTOR) signaling pathway activity. In general, SPAG5 upregulation relates to poor prognosis in cervical cancer patients, and SPAG5 is a regulator of mTOR activity during taxol treatment in cervical cancer.
Direct observation of ionic structure at solid-liquid interfaces: a deep look into the Stern Layer
Authors: Siretanu Igor , Ebeling Daniel , Andersson Martin P. , Stipp S. L. Svane , Philipse Albert , Stuart Martien Cohen , van den Ende Dirk , Mugele Frieder
Published: May 2014

The distribution of ions and charge at solid-water interfaces plays an essential role in a wide range of processes in biology, geology and technology. While theoretical models of the solid-electrolyte interface date back to the early 20th century, a detailed picture of the structure of the electric double layer has remained elusive, largely because of experimental techniques have not allowed direct observation of the behaviour of ions, i.e. with subnanometer resolution. We have made use of recent advances in high-resolution Atomic Force Microscopy to reveal, with atomic level precision, the ordered adsorption of the mono- and divalent ions that are common in natural environments to heterogeneous gibbsite/silica surfaces in contact with aqueous electrolytes. Complemented by density functional theory, our experiments produce a detailed picture of the formation of surface phases by templated adsorption of cations, anions and water, stabilized by hydrogen bonding.
Theory of non-equilibrium critical phenomena in three-dimensional condensed systems of charged mobile nanoparticles
Authors: Kuzovkov V. N. , Zvejnieks G. , Kotomin E. A.
Published: May 2014

The 3d structure of self-assembled and oppositely charged nanoparticles.
Rapid amplification/detection of nucleic acid targets utilizing a HDA/thin film biosensor
Authors: Jenison Robert , Jaeckel Heidi , Klonoski Joshua , Latorra David , Wiens Jacinta
Published: May 2014

A non-instrumented molecular diagnostics approach is described which integrates HDA amplification and thin film biosensor detection to create a platform capable of detecting pathogenic bacteria with high sensitivity and specificity.
Quality assessment of recombinant proteins by infrared spectroscopy. Characterisation of a protein aggregation related band of the Ca2+-ATPase
Authors: Li Chenge , Kumar Saroj , Montigny Cédric , le Maire Marc , Barth Andreas
Published: May 2014

FTIR spectroscopy detects aggregates of recombinantly produced protein and can therefore be used for quality control.
Interaction of fluorescent dyes with DNA and spermine using fluorescence spectroscopy
Authors: Gracie K. , Smith W. E. , Yip P. , Sutter J. U. , Birch D. J. S. , Graham D. , Faulds K.
Published: May 2014

Using fluorescence spectroscopy, spermine is shown to affect the emission of FAM and TAMRA, impacting the design of SERS-based assays.
Transmission line model analysis of transcription factors binding to oligoduplexes – differentiation of the effect of single nucleotide modifications
Authors: Rodrigues Rogério M. M. , de-Carvalho Jorge , Henriques Silvia F. , Mira Nuno P. , Sá-Correia Isabel , Ferreira Guilherme N. M.
Published: May 2014

A QCM bioanalytical methodology based on the transmission line model assesses the mechanical effects of single point mutations upon the DNA recognition by transcription factors.
The nanoscale carbon p–n junction between carbon nanotubes and N,B-codoped holey graphene enhances the catalytic activity towards selective oxidation
Authors: Wang Hong , Zheng Xiaoli , Chen Haining , Yan Keyou , Zhu Zonglong , Yang Shihe
Published: May 2014

We show the spontaneous formation of multiple nanoscale carbon p–n junctions between carbon nanotubes (CNTs) and negatively charged N,B-codoped graphene (NBG).
Carbon nanoparticle-protected aptamers for highly sensitive and selective detection of biomolecules based on nuclease-assisted target recycling signal amplification
Authors: Lin Xiaoyan , Cui Liang , Huang Yishun , Lin Ya , Xie Yi , Zhu Zhi , Yin Bincheng , Chen Xi , Yang Chaoyong James
Published: May 2014

A nuclease-assisted target recycling signal amplification method based on carbon nanoparticles for highly sensitive detection of biomolecules was developed.
Equiatomic ternary chalcogenide: PdPS and its reduced graphene oxide composite for efficient electrocatalytic hydrogen evolution
Authors: Sarkar Sujoy , Sampath Srinivasan
Published: May 2014

The PdPS–rGO composite is an excellent catalyst for HER.
Novel and selective detection of Tabun mimics
Authors: Jang Yoon Jeong , Tsay Olga G. , Murale Dhiraj P. , Jeong Jeong A. , Segev Aviv , Churchill David G.
Published: May 2014

Detection of nerve agent-related molecules based on BODIPY–salicylaldehyde oxime conjugation was studied.
Visible-light-induced direct C(sp3)–H difluromethylation of tetrahydroisoquinolines with the in situ generated difluoroenolates
Authors: Li Weipeng , Zhu Xuebin , Mao Haibin , Tang Zhongkai , Cheng Yixiang , Zhu Chengjian
Published: May 2014

A visible light promoted C(sp3)–H difluoromethylation of tetrahydroisoquinolines that uses stable and easily prepared α,α-difluorinated gem-diol as the CF2 source is disclosed.
Enantioselective Prins cyclization: BINOL-derived phosphoric acid and CuCl synergistic catalysis
Authors: Lalli Claudia , van de Weghe Pierre
Published: May 2014

The synergistic catalysis between a chiral phosphoric acid and CuCl allows the development of the first enantioselective Prins cyclization.
Catalytic CO2conversion to organic carbonates with alcohols in combination with dehydration system
Authors: Honda Masayoshi , Tamura Masazumi , Nakagawa Yoshinao , Tomishige Keiichi
Published: May 2014

This perspective highlights the direct synthesis of organic carbonates from CO2and alcohols combined with dehydration systems.
Synthesis, structure and a nucleophilic coordination reaction of Germanetellurones
Authors: Li Bin , Li Yan , Zhao Na , Chen Yuefei , Chen Yujue , Fu Gang , Zhu Hongping , Ding Yuqiang
Published: May 2014

A germylene germanetellurone adduct L(Cp)GeTe(GeCl2), a pentafluorophenyl gold(i) germanethione and germaneselone compounds L(Me)GeE(AuC6F5) (E = S and Se) are herein reported.
A rare example of nickel(ii) chains based on a heteroscorpionate-like ligand with quadruple imidazolyl interactions
Authors: Gómez-García C. J. , Escrivà E. , Mínguez Espallargas G. , Borrás-Almenar J. J. , Soto L. , Sancho A. , García-Lozano J. , Ramírez de Arellano C.
Published: May 2014

The first Ni(ii) complex with 2-di1H-2-imidazolylmethylmalonate (DIMMAL) presents an original quadruple imidazolyl embrace (QIE) and weak antiferromagnetic interactions.
Monitoring the formation of carbide crystal phases during the thermal decomposition of 3d transition metal dicarboxylate complexes
Authors: Huba Zachary J. , Carpenter Everett E.
Published: May 2014

Presented is a detailed study of the decomposition of late row 3d metal dicarboxylate complexes. It is shown that these complexes can be efficient single molecule precursors for the formation of carbide crystal phases.
Polymer based photocathodes for panchromatic tandem dye-sensitized solar cells
Authors: Shao ZhiPeng , Pan Xu , Chen HaiWei , Tao Li , Wang WenJun , Ding Yong , Pan Bin , Yang Shangfeng , Dai Songyuan
Published: May 2014

A novel polymer based photocathode with a secondary porous structure was developed for tandem dye-sensitized solar cells (pn-DSCs). Complementary absorption was realized in pn-DSCs. The resulting tandem devices achieved a panchromatic absorption and a power conversion efficiency of 1.30%.
Real-time analysis of diaquat dibromide monohydrate in water with a SERS-based integrated microdroplet sensor
Authors: Gao Rongke , Choi Namhyun , Chang Soo-Ik , Lee Eun Kyu , Choo Jaebum
Published: May 2014

We report an integrated sensor composed of two segmented flow regimes: the first being a microdroplet channel for the synthesis of silver nanoparticles and the other being a merging channel between nanoparticles and analytes to allow for SERS detection.
Insights into the effect of nanoconfinement on molecular interactions
Authors: Chen Yang , Wang Shuangshou , Ye Jin , Li Daojin , Liu Zhen , Wu Xingcai
Published: May 2014

We present a quantitative study of the effect of nanoscale confinement on molecular interactions using functionalized mesoporous silica as the host material.
High-yield fabrication of nm-size gaps in monolayer CVD graphene
Authors: Nef Cornelia , Pósa László , Makk Péter , Fu Wangyang , Halbritter András , Schönenberger Christian , Calame Michel
Published: May 2014

Herein we demonstrate the controlled and reproducible fabrication of sub-5 nm wide gaps in single-layer CVD graphene electrodes with an electroburning process and inferred the temperatures during the electroburning using Raman spectroscopy.
Design of highly sensitive and selective Au@NiO yolk–shell nanoreactors for gas sensor applications
Authors: Rai Prabhakar , Yoon Ji-Wook , Jeong Hyun-Mook , Hwang Su-Jin , Kwak Chang-Hoon , Lee Jong-Heun
Published: May 2014

Highly selective and sensitive H2S sensor was designed using Au@NiO yolk–shell nanoreactors, and its gas sensing mechanism was suggested.
Dirac fermion relaxation and energy loss rate near the Fermi surface in monolayer and multilayer graphene
Authors: Luo C. W. , Tseng P. S. , Chen H.-J. , Wu K. H. , Li L. J.
Published: May 2014

Ultrafast dynamics of Dirac fermions near the Fermi surface in monolayer and multilayer graphene are revealed using optical pump mid-infrared probe spectroscopy.
Speeding up the self-assembly of a DNA nanodevice using a variety of polar solvents
Authors: kang Di , Duan Ruixue , Tan Yerpeng , Hong Fan , Wang Boya , Chen Zhifei , Xu Shaofang , Lou Xiaoding , Wei Wei , Yurke Bernard , Xia Fan
Published: May 2014

The specific recognition and programmable assembly properties make DNA a potential material for nanodevices.
Structure-based de novo design and identification of D816V mutant-selective c-KIT inhibitors
Authors: Park Hwangseo , Lee Soyoung , Lee Suhyun , Hong Sungwoo
Published: May 2014

New 7-azaindole-based c-KIT inhibitors with nanomolar inhibitory activity and high selectivity for the gain-of-function D816V mutant were identified through the structure-based de novo design using the scoring function improved by implementing an accurate solvation free energy.
Theoretical study of the reaction of hydroxyl radicals with uridine: the influence of ribose and solvent
Authors: Gao Ya , Chen Xiayu , Zhong Li , Yao Wei , Li Shujin
Published: May 2014

The reaction of ˙OH with uridine has been investigated. The influence of ribose and the solvent effect are presented.
N,N-Dimethylaminobenzoates enable highly enantioselective Sharpless dihydroxylations of 1,1-disubstituted alkenes
Authors: Zhao Yaohong , Xing Xiangyou , Zhang Shaolong , Wang David Zhigang
Published: May 2014

Exploration of beneficial catalyst–substrate interactions in the classical Sharpless asymmetric dihydroxylations (SAD) led to the identification of allylic N,N-dimethylaminobenzoate as an efficient auxiliary for inducing high levels of enantioselectivity in 1,1-disubstituted aliphatic alkenes.
Access to novel imidazo[1,5-a]pyrazine scaffolds by the combined use of a three-component reaction and a base-assisted intramolecular cyclization
Authors: Attanasi Orazio A. , Favi Gianfranco , Giorgi Gianluca , Majer Roberta , Perrulli Francesca Romana , Santeusanio Stefania
Published: May 2014

A novel and practical two-step approach to an intriguing class of imidazo[1,5-a]pyrazines with exocyclic CX (X = CH2, O) bonds is described.
Rare Streptomyces sp. polyketides as modulators of K-Ras localisation
Authors: Salim Angela A. , Xiao Xue , Cho Kwang-Jin , Piggott Andrew M. , Lacey Ernest , Hancock John F. , Capon Robert J.
Published: May 2014

A rare class of oxanthromicin polyketides was isolated from a soil-derived Streptomyces sp. SAR-investigation showed that selected analogues can induce significant K-Ras plasma membrane mislocalisation and can synergise the K-Ras plasma membrane mislocalisation properties of staurosporine.
Application of response surface methodology for optimization of growth and lipids in Scenedesmus abundans using batch culture system
Authors: Chellamboli Chelladurai , Perumalsamy Muthiah
Published: May 2014

Owing to an increased demand for fuel and the depletion of fossil fuels, an alternative source such as algae is currently being exploited for biofuel production.
Synthesis and characterization of Cu2ZnSnS4 thin films by the sulfurization of co-electrodeposited Cu–Zn–Sn–S precursor layers for solar cell applications
Authors: Tao Jiahua , Liu Junfeng , He Jun , Zhang Kezhi , Jiang Jinchun , Sun Lin , Yang Pingxiong , Chu Junhao
Published: May 2014

Cu2ZnSnS4 (CZTS) absorbers have been successfully deposited on tin-doped indium oxide coated glass (ITO/glass) substrates by sulfurization process of co-electrodeposited Cu–Zn–Sn–S precursor thin films at various annealing temperatures ranging from 500 to 580 °C for 30 min in an atmosphere of Ar–H2S (6.5%).
Fabrication of an efficient electrodeposited Cu2ZnSnS4-based solar cells with more than 6% conversion efficiency using a sprayed Ga-doped ZnO window layer
Authors: Jiang Feng , Ikeda Shigeru , Harada Takashi , Ide Akiko , Mochihara Akiko , Yoshino Kenji , Matsumura Michio
Published: May 2014

Cost effective non-vacuum sprayed GZO layer was utilized in electrodeposited CZTS-based thin film solar cells for the first time. The thus-obtained solar device presented an appreciable conversion efficiency of 6.43%.
Bioengineering tools to elucidate and control the fate of transplanted stem cells
Authors: Sridharan Rukmani , Karp Jeffrey M. , Zhao Weian
Published: May 2014

For the last decade, stem cell therapies have demonstrated enormous potential for solving some of the most tragic illnesses, diseases and tissue defects worldwide. Currently, more than 1300 clinical trials use stem cell therapy to solve a spectrum of cardiovascular, neurodegenerative and autoimmune diseases (http://www.clinicaltrials.gov, Jan 2014, search term: stem cell therapy; only currently recruiting and completed studies are included in the search). However, the efficacy of stem cell transplantation in patients has not been well established, and recent clinical trials have produced mixed results. We attribute this lack of efficacy in part to an incomplete understanding of the fate of stem cells following transplantation and the lack of control over cell fate, especially cell-homing and therapeutic functions. In the present review, we present two of our recently developed technologies that aim to address the above-mentioned bottlenecks in stem cell therapy specifically in the areas of MSCs (mesenchymal stem cells): (i) aptamer-based cell-surface sensors to study cellular microenvironments, and (ii) mRNA engineering technology to enhance the homing and immunomodulatory efficacy of transplanted stem cells. The first engineering strategy aims to elucidate the basic cellular signalling that occurs in the microenvironment of transplanted stem cells in real time. The second technique involves a simple mRNA transfection that improves the homing and anti-inflammatory capability of MSCs. Although we have specifically applied these engineering techniques to MSCs, these strategies can be incorporated for almost any cell type to determine and control the fate of transplanted stem cells.
Mechanisms underlying vertebrate limb regeneration: lessons from the salamander
Authors: Brockes Jeremy P. , Gates Phillip B.
Published: May 2014

Limb regeneration in adult salamanders proceeds by formation of a mound of progenitor cells called the limb blastema. It provides several pointers for regenerative medicine. These include the role of differentiated cells in the origin of the blastema, the role of regenerating axons of peripheral nerves and the importance of cell specification in conferring morphogenetic autonomy on the blastema. One aspect of regeneration that has received less attention is the ability to undergo multiple episodes without detectable change in the outcome, and with minimal effect of aging. We suggest that, although such pointers are valuable, it is important to understand why salamanders are the only adult tetrapod vertebrates able to regenerate their limbs. Although this remains a controversial issue, the existence of salamander-specific genes that play a significant role in the mechanism of regeneration provides evidence for the importance of local evolution, rather than a purely ancestral mechanism. The three-finger protein called Prod1 is discussed in the present article as an exemplar of this approach.
Regenerative effects of adipose-tissue-derived stem cells for treatment of peripheral nerve injuries
Authors: Kolar Mallappa K. , Kingham Paul J.
Published: May 2014

Peripheral nerve injuries are a common occurrence affecting the nerves found outside the central nervous system. Complete nerve transections necessitate surgical re-anastomosis, and, in cases where there is a significant gap between the two ends of the injured nerve, bridging strategies are required to repair the defect. The current clinical gold standard is the nerve graft, but this has a number of limitations, including donor site morbidity. An active area of research is focused on developing other techniques to replace these grafts, by creating tubular nerve-guidance conduits from natural and synthetic materials, which are often supplemented with biological cues such as growth factors and regenerative cells. In the present short review, we focus on the use of adipose-tissue-derived stem cells and the possible mechanisms through which they may exert a positive influence on peripheral nerve regeneration, thereby enabling more effective nerve repair.
Conversion of one cell type into another: implications for understanding organ development, pathogenesis of cancer and generating cells for therapy
Authors: Corbett James L. , Tosh David
Published: May 2014

Metaplasia is the irreversible conversion of one differentiated cell or tissue type into another. Metaplasia usually occurs in tissues that undergo regeneration, and may, in a pathological context, predispose to an increased risk of disease. Studying the conditions leading to the development of metaplasia is therefore of significant clinical interest. In contrast, transdifferentiation (or cellular reprogramming) is a subset of metaplasia that describes the permanent conversion of one differentiated cell type into another, and generally occurs between cells that arise from neighbouring regions of the same germ layer. Transdifferentiation, although rare, has been shown to occur in Nature. New insights into the signalling pathways involved in normal tissue development may be obtained by investigating the cellular and molecular mechanisms in metaplasia and transdifferentiation, and additional identification of key molecular regulators in transdifferentiation and metaplasia could provide new targets for therapeutic treatment of diseases such as cancer, as well as generating cells for transplantation into patients with degenerative disorders. In the present review, we focus on the transdifferentiation of pancreatic cells into hepatocyte-like cells, the development of Barrett's metaplasia in the oesophagus, and the cellular and molecular mechanisms underlying both processes.
The biochemical determinants of tissue regeneration
Authors: Giangreco Adam , Merry Catherine L.R.
Published: May 2014

The field of regenerative medicine offers tantalizing hope for the repair and replacement of damaged organs and tissues, with the ultimate goal of restoring normal tissue function. This field represents an enormous range of biological, chemical and biophysical technologies that harness the restorative properties of living materials, especially human cells, to produce new molecular and cellular medicines, diagnostics, devices and healthcare research tools. The goal of this Biochemical Society Annual Symposium was to explore the key biochemical determinants of tissue regeneration, and we highlight the contribution of biochemistry to this emerging field of regenerative medicine.