Small Clumps Research Articles

HerschelSPIRE-FTS observations of RCW 120

The expansion of Galactic HII regions can trigger the formation of a new generation of stars. However, little is know about the physical conditions that prevail in these regions. We study the physical conditions that prevail in specific zones towards expanding HII regions that trace representative media such as the photodissociation region, the ionized region, and condensations with and without ongoing star formation. We use the SPIRE Fourier Transform Spectrometer (FTS) on board $Herschel$ to observe the HII region RCW 120. Continuum and lines are observed in the $190-670\,\mu$m range. Line intensities and line ratios are obtained and used as physical diagnostics of the gas. We used the Meudon PDR code and the RADEX code to derive the gas density and the radiation field at nine distinct positions including the PDR surface and regions with and without star-formation activity. For the different regions we detect the atomic lines [NII] at $205\,\mu$m and [CI] at $370$ and $609\,\mu$m, the $^{12}{\rm CO}$ ladder between the $J=4$ and $J=13$ levels and the $^{13}{\rm CO}$ ladder between the $J=5$ and $J=14$ levels, as well as CH$ ^{+} $ in absorption. We find gas temperatures in the range $45-250\,$K for densities of $10^4-10^6\,{\rm cm}^{-3}$, and a high column density on the order of $N_{{\rm H}}\sim10^{22}\,{\rm cm}^{-2}$ that is in agreement with dust analysis. The ubiquitousness of the atomic and CH$ ^{+} $ emission suggests the presence of a low-density PDR throughout RCW 120. High-excitation lines of CO indicate the presence of irradiated dense structures or small dense clumps containing young stellar objects, while we also find a less dense medium ($N_{{\rm H}}\sim10^{20}\,{\rm cm}^{-2}$) with high temperatures ($80-200\,$K).

Substellar fragmentation in self-gravitating fluids with a major phase transition

The existence of substellar cold H2 globules in planetary nebulae and the mere existence of comets suggest that the physics of cold interstellar gas might be much richer than usually envisioned. We study the case of a cold gaseous medium in ISM conditions which is subject to a gas-liquid/solid phase transition. First the equilibrium of general non-ideal fluids is studied using the virial theorem and linear stability analysis. Then the non-linear dynamics is studied by using simulations to characterize the expected formation of solid bodies analogous to comets. The simulations are run with a state of the art molecular dynamics code (LAMMPS). The long-range gravitational forces can be taken into account with short-range molecular forces with finite limited computational resources by using super-molecules, provided the right scaling is followed. The concept of super-molecule is tested with simulations, allowing us to correctly satisfy the Jeans instability criterion for one-phase fluids. The simulations show that fluids presenting a phase transition are gravitationally unstable as well, independent of the strength of the gravitational potential, producing two distinct kinds of sub-stellar bodies, those dominated by gravity ("planetoids") and those dominated by molecular attractive force ("comets"). Observations, formal analysis and computer simulations suggest the possibility of the formation of substellar H2 clumps in cold molecular clouds due to the combination of phase transition and gravity. Fluids presenting a phase transition are gravitationally unstable, independent of the strength of the gravitational potential. Arbitrarily small H2 clumps may form even at relatively high temperatures up to 400 - 600K, according to virial analysis. The combination of phase transition and gravity may be relevant for a wider range of astrophysical situations, such as proto-planetary disks.

The expression of β3-adrenoceptor and muscarinic type 3 receptor immuno-reactivity in the major pelvic ganglion of the rat.

Bladder afferent outflow, linked to sensation, plays a critical role in bladder pathology: abnormal outflow results in altered sensation, leading to increased voiding frequency, urge and often incontinence. β3-adrenoceptor agonists have been suggested to be beneficial in treating these symptoms. However, the absence of a significant sympathetic innervation of the detrusor and only a modest relaxation of bladder muscle by β3 agonists has questioned the therapeutic site of action of β3 agonists in the bladder. The present study was done to explore the possibility that β3-adrenoceptors might be located in the pelvic plexus. Using the rat, where the pelvic plexus is located primarily within a single ganglion, the major pelvic ganglion (MPG), immuno-histochemical approaches were used to identify structures expressing β3-adrenoceptor immuno-reactivity (β3AR-IR). The only structures found to express β3AR-IR were small-diameter tyrosine hydroxylase and vesicular mono-amine transporter immuno-reactive (TH-IR and vmat-IR) neurones. These neurones, found in clusters or singly on the periphery of the ganglion, or dispersed in smaller clumps throughout the MPG, are similar to the small intensely fluorescent (SIF) cells described previously. Not all small cells expressed β3AR-IR. A population of the small cells were also immuno-reactive to the type 3 muscarinic receptor (M3R-IR) and the P2X3 purinergic receptor (P2X3-IR). Clumps of small cells were associated with calcitonin gene-related peptide immuno-reactive (CGRP-IR) nerve fibres (putative sensory fibres) and a small number were contacted by putative cholinergic nerves expressing immuno-reactivity to vesicular acetylcholine transporter (vacht-IR). These observations are consistent with the idea that small cells are interneurons and one of the components making up complex neural circuits within the MPG. The precise physiological role of these neural elements in the MPG is unknown. However, as one therapeutic action of β3-adrenoceptor agonists is to modulate sensation, it is possible that these neural circuits may be involved in the regulation of afferent outflow and sensation.

Synergistic effect of PDGF and FGF2 for cell proliferation and hair inductive activity in murine vibrissal dermal papilla in vitro

BackgroundThe dermal papilla is composed of a small clump of mesenchymal cells, called dermal papilla cells (DPCs). DPCs closely interact with epidermal cells to give rise to hair follicles and shafts during hair follicle development and the hair cycle. DPCs are promising cell sources for hair regeneration therapy for alopecia patients. However, once DPCs are put into conventional two-dimensional culture conditions, they quickly lose their capability to produce hair follicles. ObjectiveWe aimed to expand a sufficiently large population of DPCs that retain their hair inductive activity. MethodsMurine DPCs were cultured in the presence of platelet-derived growth factor-AA (PDGF-AA) and fibroblast growth factor 2 (FGF2). Expressions of follicular-related genes were analyzed by real time PCR and hair inductive activity was determined by patch assay and chamber assay in vivo. ResultsFGF2 significantly increased the expression of platelet-derived growth factor receptor alpha (PDGFRα) in cultured vibrissal DPCs. PDGF-AA, a ligand of PDGFRα, promoted proliferation of DPCs synergistically when utilized with FGF2 and enhanced the expression of several follicular-related genes in DPCs. Hair reconstitution assays revealed that DPCs treated with both PDGF-AA and FGF-2 were able to maintain their hair inductive activity better than those treated with FGF2 alone. ConclusionBoth cell proliferation and hair inductive activity in murine DPCs are maintained by the synergistic effect of FGF2 and PDGF-AA.

Shock-produced akimotoite in the Suizhou L6 chondrite

Shock-produced akimotoite was identified in the Suizhou chondritic meteorite, which occurs in two kinds of occurrence. The first is the irregular layers of akimotoite up to 4 μm in thickness occurring in fractures and cracks of low-Ca pyroxene enclosed in the shock veins. The second is the zonal polycrystalline aggregates of akimotoite in shocked pyroxene grains close to the shock vein, where akimotoite occurs in a zonal area in between pyroxene and MgSiO3-glass as irregular small clumps up to 5 μm in size. This investigation suggests a solid-state transformation mechanism of pyroxene to akimotoite, and that akimotoite should have nucleated and grew in the area with abundant defects caused by shock deformation because the defect significantly enhances the solid-state reactivity and the kinetics of nucleation of high-pressure phase. The spatial relationship among the composed grains of pyroxene, akimotoite and MgSiO3-glass (possibly vitrified perovskite) demonstrates a temperature gradient from the vein wall to the unmelted chondritic meteorite.

A Simple and Efficient Method of Slow Freezing for Human Embryonic Stem Cells and Induced Pluripotent Stem Cells.

Protocols available for the cryopreservation of human embryonic stem (ES) and induced pluripotent stem (iPS) cells are very inefficient and laborious compared to those for the cryopreservation of murine ES/iPS cells or other general cell lines. While the vitrification method may be adequate when working with small numbers of human ES/iPS cells, it requires special skills and is unsuitable when working with large cell numbers. Here, we describe a simple and efficient method for the cryopreservation of hES/hiPS cells that is based on a conventional slow freezing method that uses a combination of Pronase/EDTA for Stem™ and CP-5E™ [final concentrations: 6 % hydroxyethyl starch, 5 % DMSO, and 5 % ethylene glycol in saline]. CP-5E™ is highly effective for the cryopreservation of small cell clumps produced by hES/hiPS colony detachment in the presence of Pronase and EDTA (Pronase/EDTA for Stem™, a formulation containing multiple digestive enzymes from Streptomyces griseus). This novel method would be quite useful for large-scale hES/iPS cell banking for use in clinical applications.

CHEMICAL COMPOSITION OF THE ESSENTIAL OIL OF PYRETHRUM BALSAMITA (L.) WILLD. FROM AZERBAIJAN

Pyrethrum balsamita (L.) Willd. (syn.: Tanacetum balsamita L.) is a wild-growing plant in Azerbaijan. P. balsamita refers to perennial plant which grows up to 25 and 90 cm. The plant is polycarpic, mezophyte. It grows in fragments, forming small clumps. This is a common plant in Azerbaijan, and mainly grows in the northern and central parts of the Minor Caucasus and mountainous part of Nakhchivan AR. It occurs in damp or swampy meadows, along the mountain streams of subalpine to alpine zone. In traditional medicine, the aerial part of P. balsamita is used as an infusion for stomach cramps as a painkiller during budding and flowering. The powder of the flowers is used as anthelmintic. Small amounts of the young leaves, stems, buds at the beginning of budding are added to salads, meat and fish soups, vegetable dishes, and the powder of herbs - in desserts and pastries, as well as other drinks and kvass as a spice. Essential oil of P. balsamita used in perfumery, cosmetic industry and also in food industry. The composition of the essential oil that hydrodistilled from the above ground parts of plant in the end of the budding and in the beginning of the flowering periods were analyzed by GC and GC/MS. The above-ground part of plant contains 0,6% of essential oil, that has brown colour and camphor odour. In total 23 components were identified. T he major compounds of essential oil were camphor (+)- ( 25,29%) and L-borneol (21,84%).

94 CHRONOLOGICAL TRANSITION OF GONOCYTES TO SPERMATOGONIAL STEM CELLS DURING PREPUBERTAL AND PUBERTAL PERIODS IN DOMESTIC CATS

The pubertal age of domestic cat (Felis catus) as defined as a complete spermatogenesis has been reported to occur around 8 months of age. During the initial phase of testicular development, the transition of gonocytes to spermatogonial stem cells (SSC) takes place within the seminiferous cords. This stage-specific transition has been demonstrated to facilitate SSC isolation and enrichment. Because information for this aspect in domestic cats is limited, this study aimed to identify the phase transition of gonocytes to SSC during newborn to puberty. Cat testes were collected and classified by age into 3 groups: group 1: 0–4 months (n = 5), group 2: 4–6 months (n = 5), and group 3: 6–12 months (n = 5). Testes were studied for conventional histology, transmission electron microscopy (TEM), and FACS analysis on GFRα-1 expression, a SSC marker. For histology, tissues were fixed, sectioned, and stained with H&E. Serial changes of germ cell development within the testes were observed using light microscopy. In addition, ultrathin sections (60 nm thickness) of testes were cut and examined with TEM for ultrastructure analysis. Immunolabelling and flow cytometry of GFRα-1 were used to identify the SSC population after testicular cell dissociation. The percentages of spermatogonia per tubule were analysed by one-way ANOVA, and data are presented as mean ± s.e. The development of testicular germ cells from gonocyte to spermatozoon was gradually demonstrated in histological sections, depending on age of the cats. For group 1, the gonocytes were clearly presented in the seminiferous cord. These gonocytes were in proliferative phase, as they frequently contained homogeneous euchromatin and less organelles. In group 2, the gonocytes transformed to spermatogonia as indicated by their small size (range 8.11–13.55 μm) with oval to flattened shape, chromatin condensation, and darkened cytoplasm. These cells migrated and settled onto the basement membrane of seminiferous cord. At this stage, mitochondria and small clumps of heterochromatin increased when compared with group 1. Some spermatogonia occasionally developed through the meiosis by 6 months of age (group 2), whereas complete spermatogenesis was first identified in 9-month testes (group 3). The percentage of spermatogonium/tubule in group 2 (15.84 ± 0.67) was significantly higher (P < 0.001) than group 1 and 3 (1.99 ± 0.22 and 6.88 ± 0.53, respectively). Because the SSC-like cells (based on their histological morphology) were predominantly found in group 2, the testes (n = 5, 4–6 months of age) were additionally digested to confirm GFRα-1 expression. Of total testicular cells, a high proportion of GFRα-1 positive cells (12.32 ± 6.31%) were identified by FACS. In conclusion, this study provides information regarding the age-dependent development of testicular germ cells in domestic cats. The findings provide the transition period of gonocytes to SSC that occurs around 4 to 6 months of age. This study can be applied for the enrichment of feline SSC upon testicular digestion.

On the nature of star-forming filaments – I. Filament morphologies

We use a suite of high-resolution molecular cloud simulations carried out with the moving mesh code arepo to explore the nature of star-forming filaments. The simulated filaments are identified and categorized from column density maps in the same manner as for recent Herschel observations. When fitted with a Plummer-like profile, the filaments are in excellent agreement with observations, and have shallow power-law profiles of p ∼ 2.2 without the need for magnetic support. When data within 1 pc of the filament centre are fitted with a Gaussian function, the average full width at half-maximum (FWHM) is ∼0.3 pc, in agreement with predictions for accreting filaments. However, if the fit is constructed using only the inner regions, as in Herschel observations, the resulting FWHM is only ∼0.2 pc. This value is larger than that measured in IC 5146 and Taurus, but is similar to that found in the Planck Galactic cold cores and in Cygnus X. The simulated filaments have a range of widths rather than a constant value. When the column density maps are compared to the 3D gas densities, the filaments seen in column density do not belong to a single structure. Instead, they are made up of a network of short ribbon-like sub-filaments reminiscent of those seen in Taurus. The sub-filaments are pre-existing within the simulated clouds, have radii similar to their Jeans radius, and are not primarily formed through fragmentation of the larger filament seen in column density. Instead, small filamentary clumps are swept together into a single column density structure by the large-scale collapse of the cloud.

Pressure-driven fragmentation of multiphase clouds at high redshift

The discovery of a hyper metal-poor star with total metallicity of $\le 10^{-5}$ Z$_\odot$, has motivated new investigations of how such objects can form from primordial gas polluted by a single supernova. In this paper we present a shock-cloud model which simulates a supernova remnant interacting with a cloud in a metal-free environment at redshift $z=10$. Pre-supernova conditions are considered, which include a multiphase neutral medium and H II region. A small dense clump ($n=100$ cm$^{-3}$), located 40 pc from a 40 M$_\odot$ metal-free star, embedded in a $n=10$ cm$^{-3}$ ambient cloud. The evolution of the supernova remnant (explosion energy $10^{52}$ erg) and its subsequent interaction with the dense clump is examined. This is the first study to include a comprehensive treatment of the non-equilibrium chemistry and associated radiative cooling that is occurring at all stages of the shock-cloud model. We have included a primordial chemistry network that covers the temperature range $10-10^9$ K, and is coupled to thermal models of atomic & molecular cooling. We find $\times10^{3}$ density enhancement of the clump (i.e maximum density $\sim 78000$ cm$^{-3}$) within this metal-free model. This is consistent with Galactic shock-cloud models considering solar metallicity gas with equilibrium cooling functions. Despite this strong compression, the cloud does not become gravitationally unstable. We find that the small cloud modelled here is destroyed for shock velocities $\gtrsim 50\,$km s$^{-1}$, and not significantly affected by shocks with velocity $\lesssim 30\,$km s$^{-1}$. Rather specific conditions are required to make such a cloud collapse.

A boat hitchhiker’s guide to survival: Cabomba caroliniana desiccation resistance and survival ability

Cabomba caroliniana is a submersed macrophyte that has become a serious invader. Cabomba predominantly spreads by stem fragments, in particular through unintentional transport on boat trailers (‘hitch hiking’). Desiccation resistance affects the potential dispersal radius. Therefore, knowledge of maximum survival times allows predicting future dispersal. Experiments were conducted to assess desiccation resistance and survival ability of cabomba fragments under various environmental scenarios. Cabomba fragments were highly tolerant of desiccation. However, even relatively low wind speeds resulted in rapid mass loss, indicating a low survival rate of fragments exposed to air currents, such as fragments transported on a boat trailer. The experiments indicated that cabomba could survive at least 3 h of overland transport if exposed to wind. However, even small clumps of cabomba could potentially survive up to 42 h. Thus, targeting the transport of clumps of macrophytes should receive high priority in management. The high resilience of cabomba to desiccation demonstrates the risk of continuing spread. Because of the high probability of fragment viability on arrival, preventing fragment uptake on boat trailers is paramount to reduce the risk of further spread. These findings will assist improving models that predict the spread of aquatic invasive macrophytes.

Interactive visual exploration of halos in large-scale cosmology simulation

Halo is one of the most important basic elements in cosmology simulation, which merges from small clumps to ever larger objects. The processes of the birth and merging of the halos play a fundamental role in studying the evolution of large scale cosmological structures. In this paper, a visual analysis system is developed to interactively identify and explore the evolution histories of thousands of halos. In this system, an intelligent structure-aware selection method in What You See Is What You Get manner is designed to efficiently define the interesting region in 3D space with 2D hand-drawn lasso input. Then the exact information of halos within this 3D region is identified by data mining in the merger tree files. To avoid visual clutter, all the halos are projected in 2D space with a MDS method. Through the linked view of 3D View and 2D graph, Users can interactively explore these halos, including the tracing path and evolution history tree.

ASSESSMENT OF THE BIOLOGICAL CHARACTERISTICS OF XYLELLA FASTIDIOSA IN XYLEM FLUID FROM A PIERCE'S DISEASE (PD) RESISTANT GRAPEVINE

The biological characteristics of Xylella fastidiosa (Xf) were investigated in vitro by examining the effect of pure xylem fluid from Pierce?s disease (PD)-resistant Vitis smalliana grapevines on Xf cell multiplication, aggregation, biofilm formation, and motility in microfluidic flow chambers. The aggregations of large clumps were formed in artificial medium, whereas small clumps were observed in V. smalliana xylem fluid. Xylem fluid from V. smalliana negatively affected twitching motility and repressed biofilm formation of Xf, whereas artificial medium enhanced twitching motility and supported robust biofilm development. The results indicate that chemical components of V. smalliana xylem fluid may affect the function of type IV pili of Xf, leading to reduced twitching motility and aggregation as compared to artificial medium.

THE EFFECTS OF FLOW-INHOMOGENEITIES ON MOLECULAR CLOUD FORMATION: LOCAL VERSUS GLOBAL COLLAPSE

Observational evidence from local star-forming regions mandates that star formation occurs shortly after, or even during, molecular cloud formation. Models of the formation of molecular clouds in large-scale converging flows have identified the physical mechanisms driving the necessary rapid fragmentation. They also point to global gravitational collapse driving supersonic turbulence in molecular clouds. Previous cloud formation models have focused on turbulence generation, gravitational collapse, magnetic fields, and feedback. Here, we explore the effect of structure in the flow on the resulting clouds and the ensuing gravitational collapse. We compare two extreme cases, one with a collision between two smooth streams, and one with streams containing small clumps. We find that structured converging flows lead to a delay of local gravitational collapse ("star formation"). Thus, more gas has time to accumulate, eventually leading to a strong global collapse, and thus to a high star formation rate. Uniform converging flows fragment hydrodynamically early on, leading to the rapid onset of local gravitational collapse and an overall low sink formation rate.

Using density functional theory to describe slowly varying fluctuations at finite temperatures: local magnetic moments in Gd and the ‘not so local’ moments of Ni

We briefly describe the density functional theory (DFT)-based ‘disordered local moment’ (DLM) picture for magnetism at finite temperatures. It shows how relatively slowly fluctuating local moments can emerge from the interacting electrons of many materials. Such entities have rigid magnitudes and fluctuate their orientations from atomic site to atomic site on a timescale long compared to other electronic times. We illustrate this theory with calculations of the magnetocaloric effect in Gd where we find excellent agreement with experiments. Fluctuating moments do not appear to establish naturally over such small regions for some other materials. We show how the DFT-DLM theory can be extended to these materials with the use of the Korringa–Kohn–Rostoker nonlocal coherent potential approximation (KKR-NLCPA) to allow for more extensive, slow magnetic fluctuations. We present the first application of this approach by revisiting the description of the magnetic fluctuations prevalent in the paramagnetic state of nickel. We find that local moments can emerge above Tc and that these form coherently over small clumps of atomic sites (4–8 sites).

Almond moth oviposition patterns in continuous layers of peanuts

The spatial distribution of eggs laid over a 48-h period by individual female almond moths, Cadra cautella Walker (Lepidoptera: Pyralidae), was examined in bioassays where peanuts covered either the center quarter (quarter-coverage) or the whole (whole-coverage) of a 120-cm square arena gridded into 3 by 3-cm cells. The mean total of eggs laid in quarter-coverage bioassays was not significantly different from the mean in whole-coverage bioassays, i. e., neither food coverage limited oviposition. However, the maximum count of eggs laid in any cell was higher in whole- than in quarter-coverage bioassays, and eggs were more aggregated near edges of the arena in whole-coverage bioassays than near edges of the peanuts in quarter-coverage bioassays. In addition, eggs were aggregated near the release point where females initially encountered food cues. These results suggest that almond moth oviposition behavior in continuous areas of peanuts was similar to patterns observed previously for stored-product insect oviposition in small, scattered food patches. In both cases, females walked or flew between separate oviposition events where eggs were laid in small clumps or lines. Possible behaviors resulting in aggregations of eggs near edges of food, walls, boundaries, or entrances are discussed and implications for precision targeting of insects in food storage areas are considered.

Managing understory light to maintain a mixture of species with different shade tolerance

Close-to-nature management of forests has been increasingly advocated. However forest managers often face difficulties in maintaining mixtures of species with different shade tolerance. In uneven aged stand management, understory light can be manipulated by modifying stand structure and composition, in addition to stand density. Using a forest radiative transfer model, we analyzed how different cutting strategies could modify light availability under the post-harvest canopy. To calibrate the model, we measured and mapped trees in 27 plots with structures ranging from secondary-successional oak forests to late-successional beech forests. We measured understory light and crown openness and verified that our forest radiative transfer model well captured the variability of understory light among the studied stands (R2=87%). We then compared cutting strategies varying in type and intensity and provided indications to promote the regeneration of mixtures of species of different shade tolerances. In particular, creating gaps of about 500m2 provided adequate light for small regeneration clumps. Cutting from below, species-specific cutting and uniform cutting were also appropriate for tree regeneration but uniform cutting required higher harvest intensity. Cutting from above slightly increased understory light and promoted more shade tolerant species.

Expression of Spermatogonial and Pluripotency Markers in Spermatogonial Stem Cells after Treatment with Different Culture Factors

Background and Aim: As condition and component of culture determine fate map of spermatogonial stem cells (SSCs), the aim of this study was to evaluate of growth factors GDNF, LIF and RA on proliferation and differentiation of SSC. Methods: SSCs were cultured in two groups: The first group GDNF and LIF and the second group RA. The number of clumps and colony formation was monitored during 1 month in culture. To identification of the colony, stained with PLZF using immunostaining. Pluripotency gene Oct 4 and neural markers MAP2, NeuroD and Nestin were analyzed by RT-PCR. Results: In the presence of GDNF and LIF, cells proliferate d rapidly and many compact clumps were appeared whereas after exposure to RA cells formed small clumps. The results of immunocytochemistry shows PLZF was detected in the group GDNF & LIF. RT-PCR showed high level expression Oct 4 in the group GDNF and LIF whereas neural markers MAP2, NeuroD and Nestin were expressed in the group RA. Conclusions: GDNF and LIF are essential for self-renewal and co lony formation of SSCs that confirm the stem cells activity of the se cells but RA inhibits stem cell activity of SSCs and induces neural differentiation of these.

Optimizing human embryonic stem cells differentiation efficiency by screening size-tunable homogenous embryoid bodies

Human embryonic stem cells (hESCs) are generally induced to differentiate by forming spherical structures termed embryoid bodies (EBs) in the presence of soluble growth factors. hEBs are generated by suspending small clumps of hESC colonies; however, the resulting hEBs are heterogeneous because this method lacks the ability to control the number of cells in individual EBs. This heterogeneity affects factors that influence differentiation such as cell–cell contact and the diffusion of soluble factors, and consequently, the differentiation capacity of each EB varies. Here, we fabricated size-tunable concave microwells to control the physical environment, thereby regulating the size of EBs formed from single hESCs. Defined numbers of single hESCs were forced to aggregate and generate uniformly sized EBs with high fidelity, and the size of the EBs was controlled using concave microwells of different diameters. Differentiation patterns in H9- and CHA15-hESCs were affected by EB size in both the absence and presence of growth factors. By screening EB size in the presence of various BMP4 concentrations, a two-fold increase in endothelial cell differentiation was achieved. Because each hESC line has unique characteristics, the findings of this study demonstrate that concave microwells could be used to screen different EB sizes and growth factor concentrations to optimize differentiation for each hESC line.

ATCA SURVEY OF AMMONIA IN THE GALACTIC CENTER: THE TEMPERATURES OF DENSE GAS CLUMPS BETWEEN Sgr A* AND Sgr B2

We present a large-scale, interferometric survey of ammonia (1,1) and (2,2) toward the Galactic Center observed with the Australia Telescope Compact Array (ATCA). The survey covers Delta l ~1degree (~150pc) at an assumed distance of 8.5 kpc) and Delta b ~0.2degree (~30pc) which spans the region between the supermassive black hole SgrA* and the massive star forming region SgrB2. The resolution is ~20'' (~0.8pc) and emission at scales >~2' (>~3.2pc) is filtered out due to missing interferometric short spacings. Consequently, the data represent the denser, compact clouds and disregards the large scale, diffuse gas. Many of the clumps align with the 100 pc dust ring and mostly anti-correlate with 1.2cm continuum emission. We present a kinetic temperature map of the dense gas. The temperature distribution peaks at ~38K with a width at half maximum between 18K and 61K (measurements sensitive within Tkin~10-80K). Larger clumps are on average warmer than smaller clumps which suggests internal heating sources. Our observations indicate that the circumnuclear disk ~1.5 pc around SgrA* is supplied with gas by the 20km/s molecular cloud. This gas is substantially cooler than gas ~3-15pc away from SgrA*. We find a strong temperature gradient across SgrB2. Ammonia column densities correlate well with SCUBA 850um fluxes, but the relation is shifted from the origin, which may indicate a requirement for a minimum amount of dust to form and shield ammonia. Around the Arches and Quintuplet clusters we find shell morphologies with UV-influenced gas in their centers, followed by ammonia and radio continuum layers.