2,723 research outputs found
Synergistic co-cultivation of activated sludge and microalgae in enhancing lipid production and N-laden wastewater treatment
The influence of inoculation ratios of activated sludge and microalgae were investigated in this study in the aspects of biomass yield, lipid yield and total nitrogen (TN) removal efficiency. It was observed that mixed culture of activated sludge/microalgae with the ratio 1:1 and 1:0.75 achieved a maximum lipid production up to 0.144 g/L and 0.133 g/L as compared with microalgae culture alone, which was only 0.081 g/L. The highest total nitrogen (TN) removal was observed with 1:1 and 1:0.75 ratios of activated sludge/microalgae cultures ranging from 96.3-96.9% removal efficiency, which was an improvement of about 90% removal efficiency compared to the activated sludge culture (6.25±0.08%). The flocculation efficiency was generally improved in mixed cultures of activated sludge andmicroalgae in comparison with only activated sludge culture and microalgae culture alone.Keywords: activated sludge; microalgae; co-cultivation; lipid; nitrogen removal
Optimization of Growth Medium for Efficient Cultivation of Lactobacillus salivarius i 24 using Response Surface Method
Production of Lactobacillus salivarius i 24, a probiotic strain for chicken, was studied in batch fermentation using 500 mL Erlenmeyer flask. Response surface method (RSM) was used to optimize the medium for efficient cultivation of the bacterium. The factors investigated were yeast extract, glucose and initial culture pH. A polynomial regression model with cubic and quartic terms was used for the analysis of the experimental data. Estimated optimal conditions of the factors for growth of L. salivarius i 24 were; 3.32 % (w/v) glucose, 4.31 % (w/v) yeast extract and initial culture pH of 6.10
Submillimeter Array multiline observations of the massive star-forming region IRAS 18089-1732
Submillimeter Array (SMA) observations of the high-mass star-forming region
IRAS 18089-1732 in the 1 mm and 850 m band with 1 GHz bandwidth reveal a
wealth of information. We present the observations of 34 lines from 16
different molecular species. Most molecular line maps show significant
contributions from the outflow, and only few molecules are confined to the
inner core. We present and discuss the molecular line observations and outline
the unique capabilities of the SMA for future imaging line surveys at high
spatial resolution.Comment: Accepted for ApJ Letters, SMA special volum
SMA outflow/disk studies in the massive star-forming region IRAS18089-1732
SMA observations of the massive star-forming region IRAS 18089-1732 in the
1mm and 850mu band reveal outflow and disk signatures in different molecular
lines. The SiO(5--4) data show a collimated outflow in the northern direction.
In contrast, the HCOOCH3(20--19) line, which traces high-density gas, is
confined to the very center of the region and shows a velocity gradient across
the core. The HCOOCH3 velocity gradient is not exactly perpendicular to the
outflow axis but between an assumed disk plane and the outflow axis. We
interpret these HCOOCH3 features as originating from a rotating disk that is
influenced by the outflow and infall. Based on the (sub-)mm continuum emission,
the mass of the central core is estimated to be around 38M_sun. The dynamical
mass derived from the HCOOCH3 data is 22Msun, of about the same order as the
core mass. Thus, the mass of the protostar/disk/envelope system is dominated by
its disk and envelope. The two frequency continuum data of the core indicate a
low dust opacity index beta ~ 1.2 in the outer part, decreasing to beta ~ 0.5
on shorter spatial scales.Comment: 7 pages of text, 1 table, 3 figures, accepted for ApJ Letter
Studies of Wilmsâ Tumor (WT1) Gene Expression in Adult Acute Leukemias in Singapore
Biomarkers provide certain values for diagnosis, monitor treatment efficacy, or for the development of novel therapeutic approach for particular diseases. Thus, the identification of specific of biomarkers for specific medical problems, including malignant diseases may be valuable in medical practice. In the study, we have used the Wilmsâ tumor gene (WT1) as a biomarker to evaluate its expression in local adult patients with newly diagnosed acute leukemia, including both acute myeloid and lymphoid leukemias (AML and ALL)
Development of a novel cell-based assay system EPISSAY for screening epigenetic drugs and liposome formulated decitabine
Extent: 11 p.BACKGROUND: Despite the potential of improving the delivery of epigenetic drugs, the subsequent assessment of changes in their epigenetic activity is largely dependent on the availability of a suitable and rapid screening bioassay. Here, we describe a cell-based assay system for screening gene reactivation. METHODS: A cell-based assay system (EPISSAY) was designed based on a silenced triple-mutated bacterial nitroreductase TMnfsB fused with Red-Fluorescent Protein (RFP) expressed in the non-malignant human breast cell line MCF10A. EPISSAY was validated using the target gene TXNIP, which has previously been shown to respond to epigenetic drugs. The potency of a epigenetic drug model, decitabine, formulated with PEGylated liposomes was also validated using this assay system. RESULTS: Following treatment with DNA methyltransferase (DNMT) and histone deacetylase (HDAC) inhibitors such as decitabine and vorinostat, increases in RFP expression were observed, indicating expression of RFP-TMnfsB. The EPISSAY system was then used to test the potency of decitabine, before and after PEGylated liposomal encapsulation. We observed a 50% higher potency of decitabine when encapsulated in PEGylated liposomes, which is likely to be due to its protection from rapid degradation. CONCLUSIONS: The EPISSAY bioassay system provides a novel and rapid system to compare the efficiencies of existing and newly formulated drugs that reactivate gene expression.Sue Ping Lim, Raman Kumar, Yamini Akkamsetty, Wen Wang, Kristen Ho, Paul M. Neilsen, Diego J. Walther, Rachel J. Suetani, Clive Prestidge and David F. Calle
Prevalence of Tidal Interactions among Local Seyfert Galaxies: The Control Experiment
We test whether there is a relation between the observed tidal interactions
and Seyfert activity by imaging in HI twenty inactive galaxies at the same
spatial resolution and detection threshold as the Seyfert sample. This control
sample of inactive galaxies were closely matched in Hubble type, range in size
and inclination, and have roughly comparable galaxy optical luminosity to the
Seyfert galaxies. We find that only ~15% of the galaxies in our control sample
are disturbed in HI, whereas the remaining ~85% show no disturbances whatsoever
in HI. Even at a spatial resolution of ~10 kpc, none of the latter galaxies
show appreciable HI disturbances reminiscent of tidal features.
In a companion paper (Kuo et al. 2008), we report results from the first
systematic imaging survey of Seyfert galaxies in atomic hydrogen (HI) gas. We
find that only ~28% of the eighteen Seyfert galaxies in that sample are visibly
disturbed in optical starlight. By contrast, ~94% of the same Seyfert galaxies
are disturbed spatially and usually also kinematically in HI gas on galactic
scales of >~20 kpc. In at least ~67% and up to perhaps ~94% of cases, the
observed disturbances can be traced to tidal interactions with neighboring
galaxies detected also in HI. The dramatic contrast between the observed
prevalence of HI disturbances in the Seyfert and control samples implicates
tidal interactions in initiating events that lead to luminous Seyfert activity
in a large fraction of local disk galaxies.Comment: 38 pages, 27 figures, Accepted for publication in ApJ. Changes from
previous version: The title of the previous version of this paper appeared in
Astroph was incorrect. It has been replaced with the correct on
Search for Calibrators for the Submillimeter Array: I. High-Mass Star Forming Regions
We present initial results of an ongoing search for interferometric
calibrators at submillimeter (sub-mm) wavelengths with the Submillimeter Array
(SMA). Powerful radio galaxies are commonly used as calibrators at centimeter
and millimeter wavelengths, but many are not strong enough to serve as
calibrators at sub-mm wavelengths because of their rapidly declining flux
densities toward shorter wavelengths. The inability to find a calibrator close
to the target source may limit or even prevent us from imaging many interesting
sources at sub-mm wavelengths. Here, we investigate whether high-mass
protostellar objects and ultracompact HII regions can serve as useful
calibrators for the SMA. The dust emission associated with these objects makes
them among the brightest sub-mm sources in the sky. Our observations at 0.85 mm
(345 GHz) with an angular resolution of ~3" reveal that although a large
fraction of the dust emission originates from an extended ``halo'' component, a
compact unresolved component often remains that when sufficiently strong may
serve as a useful calibrator. These observations also provide a first glimpse
at the small-scale distribution of dust around ultracompact HII regions and
high-mass protostellar objects at sub-mm wavelengths. We discuss the origin of
the core-halo structure seen in many sources, and conclude with suggestions for
future searches for calibrators with the SMA.Comment: 3 figures, accepted for publication in ApJ Letter
Mapping the Outflow from G5.89-0.39 in SiO(5-4)
We have mapped the ultracompact HII region, G5.89-0.39, and its molecular
surroundings with the Submillimeter Array at 2".8 x 1".8 angular resolution in
1.3 mm continuum, SiO(5-4), and eight other molecular lines. We have resolved
for the first time the highly energetic molecular outflow in this region. At
this resolution, the outflow is definitely bipolar and appears to originate in
a 1.3 mm continuum source. The continuum source peaks in the center of the HII
region. The axis of the outflow lines up with a recently discovered O5V star.Comment: 3 Figures, Accepted for publication in ApJ Letter
- âŠ