164 research outputs found
An improved single-step lysis protocol to measure luciferase bioluminescence in Plasmodium falciparum
This report describes the optimization and evaluation of a simple single-step lysis protocol to measure luciferase bioluminescence from genetically modified Plasmodium falciparum. This protocol utilizes a modified commercial buffer to improve speed of assay and consistency in the bioluminescence signal measured by reducing the manipulation steps required to release the cytoplasmic fraction. The utility of this improved assay protocol is demonstrated in typical assays that explore absolute and temporal gene expression activity
Comparison of the absolute and relative efficiencies of electroporation-based transfection protocols for Plasmodium falciparum.
BACKGROUND: Several electroporation protocols exist to transfect exogenous DNA into Plasmodium falciparum. To date, however, only a subjective analysis of their relative efficiencies has been reported. METHODS: A time-course of luciferase reporter expression is used to provide an objective quantitative analysis of the absolute efficiency of three electroporation techniques; direct electroporation of ring stage infected erythrocytes, preloading of erythrocytes and a novel "double-tap" protocol that combines both approaches. RESULTS: Preloading of erythrocytes shows a mean efficiency of 9.59 x 10(-6), some 5-180 fold more efficient than matched experiments utilizing the "double-tap" and direct electroporation of ring stage infected erythrocytes alone, respectively. CONCLUSION: Evidence presented here provides the first quantitative assessment of both the absolute and relative efficiencies of a key molecular tool used to study the biology and pathogenesis of this important human pathogen
Testing Superstring Theories with Gravitational Waves
We provide a simple transfer function that determines the effect of an early
matter dominated era on the gravitational wave background and show that a large
class of compactifications of superstring theory might be tested by
observations of the gravitational wave background from inflation. For large
enough reheating temperatures > 10^9 \GeV the test applies to all models
containing at least one scalar with mass < 10^{12}\GeV that acquires a large
initial oscillation amplitude after inflation and has only gravitational
interaction strength, i.e., a field with the typical properties of a modulus.Comment: 5 pages 2 figures, v2: changes in presentation, refs revised, matches
version in print in PR
Evaluation of bioluminescence-based assays of anti-malarial drug activity
Transgenic Plasmodium falciparum expressing luciferase offers an attractive bioluminescence-based assay platform for the investigation of the pharmacological properties of anti-malarial drugs. Here a side-by-side comparison of bioluminescence and fluorescence-based assays, utilizing a luciferase reporter cassette that confers a strong temporal pattern of luciferase expression during the S-phase of intraerythrocytic development, is reported
Sources of End Zone Cracking of Pretensioned Concrete Girders
Recent developments of high performance concrete, increasing amounts of prestressing, and increasing use of deep girders have resulted in increasing popularity of precast pretensioned concrete girders in bridge construction. These developments have increasingly contributed to end zone cracking. This paper summarizes the interim results of an ongoing research sponsored by the National Cooperative Highway Research Program (NCHRP) Project 18-14. The objectives of the research are: (1) to establish procedures for the acceptance, repair, or rejection of precast/prestressed concrete girders with longitudinal web cracking, and (2) to prepare a user\u27s manual for the application of these procedures. The results from a national survey of fabricators and users of pretensioned concrete girders and an extensive literature review are presented in this paper
Facing Real-World Challenges of Immunogenicity in Pediatric Inflammatory Bowel Disease
The advent of biological therapies drastically altered the landscape of inflammatory bowel disease (IBD) treatment, making long-term steroid-free remission possible for thousands of patients living with this chronic inflammatory condition that compromises the integrity of the gastrointestinal mucosa. Unfortunately, up to 65% of patients with IBD develop anti-drug antibodies to biologics (1). This is especially problematic for pediatrics, where treatment options are substantially more limited than for adult patients. Currently, only two biologics have approval from the United States (U.S.) Food and Drug Administration (FDA) for pediatric indications in IBD, anti-TNF-α agents infliximab (IFX), and adalimumab (ADM). The fear of losing these two agents to immunogenicity is very real for the providers and the families of the ~70,000 children affected by IBD in the U.S. (2)
Immunogenicity in Clinical Practice and Drug Development: When is it Significant?
Managing immunogenicity in clinical practice and during drug development was a recent topic at the ASCPT 2019 annual meeting. This commentary expands on the discussion to facilitate a broader engagement across the community. The intent is to provide a rationale for ongoing research into the current gaps in assessing and interpreting immunogenicity in drug development and managing clinical immunogenicity for an approved drug. The following are highlighted: (i) Immunogenicity Considerations in Clinical Practice, (ii) Immunogenicity Testing and Current Limitations, (iii) Immunogenicity Risk Assessment and Mitigation, and (iv) Quantitative Systems Pharmacology (QSP) models of Immunogenicity
Gravitino Dark Matter in Tree Level Gauge Mediation with and without R-parity
We investigate the cosmological aspects of Tree Level Gauge Mediation, a
recently proposed mechanism in which the breaking of supersymmetry is
communicated to the soft scalar masses by extra gauge interactions at the tree
level. Embedding the mechanism in a Grand Unified Theory and requiring the
observability of sfermion masses at the Large Hadron Collider, it follows that
the Lightest Supersymmetric Particle is a gravitino with a mass of the order of
10 GeV. The analysis in the presence of R-parity shows that a typical Tree
Level Gauge Mediation spectrum leads to an overabundance of the Dark Matter
relic density and a tension with the constraints from Big Bang Nucleosynthesis.
This suggests to relax the exact conservation of the R-parity. The underlying
SO(10) Grand Unified Theory together with the bounds from proton decay provide
a rationale for considering only bilinear R-parity violating operators. We
finally analyze the cosmological implications of this setup by identifying the
phenomenologically viable regions of the parameter space.Comment: 28 pages, 5 figures. References added. To appear in JHE
Dark Radiation and Dark Matter in Large Volume Compactifications
We argue that dark radiation is naturally generated from the decay of the
overall volume modulus in the LARGE volume scenario. We consider both
sequestered and non-sequestered cases, and find that the axionic superpartner
of the modulus is produced by the modulus decay and it can account for the dark
radiation suggested by observations, while the modulus decay through the
Giudice-Masiero term gives the dominant contribution to the total decay rate.
In the sequestered case, the lightest supersymmetric particles produced by the
modulus decay can naturally account for the observed dark matter density. In
the non-sequestered case, on the other hand, the supersymmetric particles are
not produced by the modulus decay, since the soft masses are of order the heavy
gravitino mass. The QCD axion will then be a plausible dark matter candidate.Comment: 27 pages, 4 figures; version 3: version published in JHE
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