1,159 research outputs found
NASA Docking System Block 1: NASA's New Direct Electric Docking System Supporting ISS and Future Human Space Exploration
The NASA Docking System (NDS) Block 1 is a key component of NASA's vision for space exploration. It is designed to provide capability for visiting vehicles to dock to the International Space Station's recently-installed International Docking Adapter ports. It is the first docking system to be developed by NASA since the Apollo-Soyuz Test Project of the 1970's. The NDS Block 1 includes provisions for capture, structural attachment, power/data transfer, and undocking. It uses a direct-drive electromechanical Stewart Platform capture system architecture, along with an innovative automated control scheme, to achieve an unprecedented level of performance and simplicity. Its design implements the new International Docking System Standard, which will be a key enabler of diverse and flexible exploration missions in future iterations. NDS qualification was completed in 2017 to support a planned first flight in 2018 on the Boeing CST-100 Starliner
Design, synthesis and evaluation of praziquantel analogues and new molecular hybrids as potential antimalarial and anti-schistosomal agents
Malaria and schistosomiasis are two of the neglected tropical diseases that persistently wreak havoc worldwide. Although many antimalarial drugs such as chloroquine are readily available, the emergence of drug resistance necessitates the development of new therapies to combat this disease. Conversely, Praziquantel (PZQ) remains the sole effective drug against schistosomiasis, but its extensive use raises concerns about the potential for drug resistance to develop. In this project, the concept of molecular hybridization was used as a strategy to design the synthesis of new molecular hybrids with potential antimalarial and antischistosomal activity. A total of seventeen molecular hybrids and two PZQ analogues were prepared by coupling 6-alkylpraziquanamines with cinnamic acids and cyclohexane carboxylic acid, respectively. The synthesised compounds were evaluated for their antimalarial and antischistosomal activity; while all of the above compounds were inactive against Plasmodium falciparum (IC(50) > 6 µM), many were active against schistosomiasis with four particular compounds exhibiting up to 100% activity against newly transformed schistosomula and adult worms at 50 µM. Compared to PZQ, the reference drug, the activity of which is 91.7% at 1 µM, one particular molecular hybrid, compound 32, which bears a para-isopropyl group on the cinnamic acid moiety, exhibited a notable activity at 10 µM (78.2% activity). This compound has emerged as the front runner candidate that might, after further optimization, hold promise as a potential lead compound in the fight against schistosomiasis
Research Needs and Challenges in the Food, Energy and Water System: Findings from an NSF Funded Workshop
In October 2015, the Center for Agricultural and Rural Development at Iowa State University, Ames, Iowa hosted a two-day National Science Foundation-funded workshop exploring the challenges and pitfalls associated with integrating biophysical and economic models. The workshop brought together leading economists, statisticians, crop scientists, hydrologists, climate scientists, and other biophysical modelers, to identify and address the key scientific, engineering, and data challenges associated with understanding our food, energy, and water (FEW) system. Approximately 80 people attended the workshop with about half of them representing social scientists (primarily economists) and the rest from the physical and natural sciences. Economics and social sciences were intentionally emphasized so that the findings would be particularly relevant to research needs in those fields
Green fluorescent diamidines as diagnostic probes for trypanosomes
LED fluorescence microscopy offers potential benefits to the diagnosis of human African trypanosomiasis, as well as to other aspects of diseases management, such as detection of drug resistant strains. To advance such approaches reliable and specific fluorescent markers to stain parasites in human fluids are needed. Here we report a series of novel green fluorescent diamidines and their suitability as probes to stain trypanosomes
Electrostatic Patch Effect in Cylindrical Geometry. I. Potential and Energy between Slightly Non-Coaxial Cylinders
We study the effect of any uneven voltage distribution on two close
cylindrical conductors with parallel axes that are slightly shifted in the
radial and by any length in the axial direction. The investigation is
especially motivated by certain precision measurements, such as the Satellite
Test of the Equivalence Principle (STEP). By energy conservation, the force can
be found as the energy gradient in the vector of the shift, which requires
determining potential distribution and energy in the gap. The boundary value
problem for the potential is solved, and energy is thus found to the second
order in the small transverse shift, and to lowest order in the gap to cylinder
radius ratio. The energy consists of three parts: the usual capacitor part due
to the uniform potential difference, the one coming from the interaction
between the voltage patches and the uniform voltage difference, and the energy
of patch interaction, entirely independent of the uniform voltage. Patch effect
forces and torques in the cylindrical configuration are derived and analyzed in
the next two parts of this work.Comment: 26 pages, 1 Figure. Submitted to Classical and Quantum Gravit
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