3,338 research outputs found
Two-phase flow modeling of solid dissolution in liquid for nutrient mixing improvement in algal raceway ponds
Achieving optimal nutrient concentrations is essential to increasing the biomass
productivity of algal raceway ponds. Nutrient mixing or distribution in raceway ponds is significantly
affected by hydrodynamic and geometric properties. The nutrient mixing in algal raceway ponds under
the influence of hydrodynamic and geometric properties of ponds is yet to be explored. Such a study is
required to ensure optimal nutrient concentrations in algal raceway ponds. A novel computational fluid
dynamics (CFD) model based on the Euler–Euler numerical scheme was developed to investigate
nutrient mixing in raceway ponds under the effects of hydrodynamic and geometric properties.
Nutrient mixing was investigated by estimating the dissolution of nutrients in raceway pond water.
Experimental and CFD results were compared and verified using solid–liquid mass transfer coefficient
and nutrient concentrations. Solid–liquid mass transfer coefficient, solid holdup, and nutrient
concentrations in algal pond were estimated with the effects of pond aspect ratios, water depths,
paddle wheel speeds, and particle sizes of nutrients. From the results, it was found that the proposed
CFD model effectively simulated nutrient mixing in raceway ponds. Nutrient mixing increased in
narrow and shallow raceway ponds due to effective solid–liquid mass transfer. High paddle wheel
speeds increased the dissolution rate of nutrients in raceway ponds
A Physiologically-Based Pharmacokinetic Model for Targeting Calcitriol-Conjugated Quantum Dots to Inflammatory Breast Cancer Cells.
Quantum dots (QDs) conjugated with 1,25 dihydroxyvitamin D3 (calcitriol) and Mucin-1 (MUC-1) antibodies (SM3) have been found to target inflammatory breast cancer (IBC) tumors and reduce proliferation, migration, and differentiation of these tumors in mice. A physiologically-based pharmacokinetic model has been constructed and optimized to match experimental data for multiple QDs: control QDs, QDs conjugated with calcitriol, and QDs conjugated with both calcitriol and SM3 MUC1 antibodies. The model predicts continuous QD concentration for key tissues in mice distinguished by IBC stage (healthy, early-stage, and late-stage). Experimental and clinical efforts in QD treatment of IBC can be augmented by in silico simulations that predict the short-term and long-term behavior of QD treatment regimens
Dark Matter in the Coming Decade: Complementary Paths to Discovery and Beyond
In this report we summarize the many dark matter searches currently being
pursued through four complementary approaches: direct detection, indirect
detection, collider experiments, and astrophysical probes. The essential
features of broad classes of experiments are described, each with their own
strengths and weaknesses. The complementarity of the different dark matter
searches is discussed qualitatively and illustrated quantitatively in two
simple theoretical frameworks. Our primary conclusion is that the diversity of
possible dark matter candidates requires a balanced program drawing from all
four approaches.Comment: Report prepared for the Community Summer Study (Snowmass) 2013, on
behalf of Cosmic Frontier Working Groups 1-4 (CF1: WIMP Dark Matter Direct
Detection, CF2: WIMP Dark Matter Indirect Detection, CF3: Non-WIMP Dark
Matter, and CF4: Dark Matter Complementarity); published versio
Stat5 determines the development of mammary alveolar cells
Functional development of mammary epithelium during pregnancy depends on prolactin signaling. However, the underlying molecular and cellular events are not fully understood. We examined the specific contributions of the prolactin receptor (PrlR) and the signal transducers and activators of transcription 5a and 5b (referred to as Stat5) in the formation and differentiation of mammary alveolar epithelium. PrlR- and Stat5-null mammary epithelia were transplanted into wild-type hosts, and pregnancy-mediated development was investigated at a histological and molecular level. Stat5-null mammary epithelium developed ducts but failed to form alveoli, and no milk protein gene expression was observed. In contrast, PrlR-null epithelium formed alveoli-like structures with small open lumina. Electron microscopy revealed undifferentiated features of organelles and a perturbation of cell–cell contacts in PrlR- and Stat5-null epithelia. Expression of NKCC1, an Na-K-Cl cotransporter characteristic for ductal epithelia, and ZO-1, a protein associated with tight junction, were maintained in the alveoli-like structures of PrlR- and Stat5-null epithelia. In contrast, the Na-Pi cotransporter Npt2b, and the gap junction component connexin 32, usually expressed in secretory epithelia, were undetectable in PrlR- and Stat5- null mice. These data demonstrate that signaling via the PrlR and Stat5 is critical for the proliferation and differentiation of mammary alveoli during pregnancy
Synthetic long peptide booster immunization in rhesus macaques primed with replication-competent NYVAC-C-KC induces a balanced CD4/CD8 T-cell and antibody response against the conserved regions of HIV-1.
The Thai trial (RV144) indicates that a prime-boost vaccine combination that induces both T-cell and antibody responses may be desirable for an effective HIV vaccine. We have previously shown that immunization with synthetic long peptides (SLP), covering the conserved parts of SIV, induced strong CD4 T-cell and antibody responses, but only modest CD8 T-cell responses. To generate a more balanced CD4/CD8 T-cell and antibody response, this study evaluated a pox-vector prime/SLP boost strategy in rhesus macaques. Priming with a replication-competent NYVAC, encoding HIV-1 clade C gag, pol and nef, induced modest IFNγ T-cell immune responses, predominantly directed against HIV-1 Gag. Booster immunization with SLP, covering the conserved parts of HIV-1 Gag, Pol and Env, resulted in a more than 10-fold increase in IFNγ ELISpot responses in four of six animals, which were predominantly HIV-1 Pol-specific. The animals showed a balanced polyfunctional CD4 and CD8 T-cell response and high Ab titres.This project was conducted under the auspices of of the Poxvirus T-cell Vaccine Discovery Consortium (PTVDC) as part of the Collaboration for AIDS Vaccine Discovery (CAVD) with support from the Bill and Melinda Gates Foundation.This is the accepted manuscript of a paper published in the Journal of General Virology (Mooij P, et al., Journal of General Virology, 2015, 96, 1478-1483, doi:10.1099/vir.0.000074). The final version is available at http://dx.doi.org/10.1099/vir.0.00007
Zeolite Y supported nickel phosphide catalysts for the hydrodenitrogenation of quinoline as a proxy for crude bio-oils from hydrothermal liquefaction of microalgae
This work demonstrates the potential of zeolite Y supported nickel phosphide materials as
highly active catalysts for the upgrading of bio-oil as improved alternative to noble metal and
transition metal sulphide systems. Our systematic work studied the effect of using different
counterions (NH4
+
, H+
, K+ and Na+
) and Si/Al ratios (2.56 and 15) of the zeolite Y. It
demonstrates that whilst the zeolite counterion itself has little impact on the catalytic activity
of the bare Y-zeolite, it has a strong influence on the activity of the resulting nickel
phosphide catalysts. This effect is related to the nature of the nickel phases formed during the
synthesis process Zeolites containing K+
and Na+
favour the formation of a mixed
Ni12P5/Ni2P phase, H+ Y produces both Ni2P and metallic Ni, whereas NH4
+ Y produces pure
Ni2P, which can be attributed to the strength of the phosphorus-aluminium interaction and the
metal reduction temperature. Using quinoline as a model for the nitrogen-containing
compounds in bio-oils, it is shown that the hydrodenitrogenation activity increases in the
order Ni2P > Ni0 > Ni12P5. While significant research has been dedicated to the development of bio-oils produced by thermal liquefaction of biomass, surprisingly little work has been
conducted on the subsequent catalytic upgrading of these oils to reduce their heteroatom
content and enable processing in conventional petrochemical refineries. This work provides
important insights for the design and deployment of novel active transition metal catalysts to
enable the incorporation of bio-oils into refineries
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