1,348 research outputs found
Gene therapy for B-cell lymphoma in a SCID mouse model using an immunoglobulin-regulated diphtheria toxin gene delivered by a novel adenovirus-polylysine conjugate
Binding-incompetent adenovirus facilitates molecular conjugate-mediated gene transfer by the receptor-mediated endocytosis pathway
Molecular conjugate vectors may be constructed that accomplish high efficiency gene transfer by the receptor-mediated endocytosis pathway. In order to mediate escape from lysosomal degradation, we have incorporated adenoviruses into the functional design of the conjugate. In doing so, however, we have introduced an additional ligand, which can bind to receptors on the cell surface, undermining the potential for cell specific targeting. To overcome this, we have treated the adenovirus with a monoclonal anti-fiber antibody, which renders the virus incapable of binding to its receptor. The result is a multi-functional molecular conjugate vector, which has preserved its binding specificity while at the same time being capable of preventing lysosomal degradation of endosome-internalized conjugate-DNA complexes. This finding indicates that adenoviral binding is not a prerequisite for adenoviral-mediated endosome disruption
Hands-Free Control Interfaces for an Extra Vehicular Jetpack
The National Aeronautics and Space Administration (NASA) strategic vision includes, as part of its long-term goals, the exploration of deep space and Near Earth Asteroids (NEA). To support these endeavors, funds have been invested in research to develop advanced exploration capabilities. To enable the human mobility necessary to effectively explore NEA and deep space, a new extravehicular activity (EVA) Jetpack is under development at the Johnson Space Center. The new design leverages knowledge and experience gained from the current astronaut rescue device, the Simplified Aid for EVA Rescue (SAFER). Whereas the primary goal for a rescue device is to return the crew to a safe haven, in-space exploration and navigation requires an expanded set of capabilities. To accommodate the range of tasks astronauts may be expected to perform while utilizing the Jetpack, it was desired to offer a hands-free method of control. This paper describes the development and innovations involved in creating two hands-free control interfaces and an experimental test platform for a suited astronaut flying the Jetpack during an EVA
The metaphysics of Machian frame-dragging
The paper investigates the kind of dependence relation that best portrays Machian frame-dragging in general relativity. The question is tricky because frame-dragging relates local inertial frames to distant distributions of matter in a time-independent way, thus establishing some sort of non-local link between the two. For this reason, a plain causal interpretation of frame-dragging faces huge challenges. The paper will shed light on the issue by using a generalized structural equation model analysis in terms of manipulationist counterfactuals recently applied in the context of metaphysical enquiry by Schaffer (2016) and Wilson (2017). The verdict of the analysis will be that frame-dragging is best understood in terms of a novel type of dependence relation that is half-way between causation and grounding
What triggers a microcrack in printed engineering parts produced by selective laser sintering on the first place?
The proximity of un-melted particles within Selective Laser Sintered (SLS) printed engineering parts made of Nylon-12 is found as a major triggering effect for cracking and ultimately failure. The numerical investigation, by means of the eXtended Finite Element Method (XFEM), was performed over samples with different arrangements of un-melted particles obtained experimentally. The onset and propagation of microcracks was simulated. This included inherently how the degree of particle melt (DPM) in SLS parts affects and controls both crack initiation and propagation. The results evidenced that a microcrack started invariably between the two closest un-melted particles in all numerical tests performed considering different arrangements of un-melted particles
Rapidly increasing collimation and magnetic field changes of a H2O maser outflow
W75N(B) is a massive star-forming region that contains three radio continuum
sources (VLA 1, VLA 2, and VLA 3), which are thought to be three massive young
stellar objects at three different evolutionary stages. VLA 1 is the most
evolved and VLA 2 the least evolved source. The 22 GHz H2O masers associated
with VLA 1 and VLA 2 have been mapped at several epochs over eight years. While
the H2O masers in VLA 1 show a persistent linear distribution along a radio
jet, those in VLA 2 are distributed around an expanding shell. Furthermore, H2O
maser polarimetric measurements revealed magnetic fields aligned with the two
structures. Using new polarimetric observations of H2O masers, we aim to
confirm the elliptical expansion of the shell-like structure around VLA 2 and,
at the same time, to determine if the magnetic fields around the two sources
have changed. The NRAO Very Long Baseline Array was used to measure the linear
polarization and the Zeeman-splitting of the 22 GHz H2O masers towards the
massive star-forming region W75N(B). The H2O maser distribution around VLA 1 is
unchanged from that previously observed. We made an elliptical fit of the H2O
masers around VLA 2. We find that the shell-like structure is still expanding
along the direction parallel to the thermal radio jet of VLA 1. While the
magnetic field around VLA 1 has not changed in the past 7 years, the magnetic
field around VLA 2 has changed its orientation according to the new direction
of the major-axis of the shell-like structure and it is now aligned with the
magnetic field in VLA 1.Comment: 10 pages (5 + online material), 3 figures, 4 tables, accepted by
Astronomy & Astrophysics Lette
A gorilla adenovirus-based vaccine against Zika virus induces durable immunity and confers protection in pregnancy
The teratogenic potential of Zika virus (ZIKV) has made the development of an effective vaccine a global health priority. Here, we generate two gorilla adenovirus-based ZIKV vaccines that encode for pre-membrane (prM) and envelope (E) proteins (GAd-Zvp) or prM and the ectodomain of E protein (GAd-Eecto). Both vaccines induce humoral and cell-mediated immune responses and prevent lethality after ZIKV challenge in mice. Protection is antibody dependent, CD
VLA 3.5 cm continuum sources in the Serpens cloud core
We present VLA 3.5 cm continuum observations of the Serpens cloud core. 22
radio continuum sources are detected. 16 out of the 22 cm sources are suggested
to be associated with young stellar objects (Class 0, Class I, flat-spectrum,
and Class II) of the young Serpens cluster. The rest of the VLA sources
plausibly are background objects. Most of the Serpens cm sources likely
represent thermal radio jets; on the other hand, the radio continuum emission
of some sources could be due to a gyrosynchroton mechanism arising from
coronally active young stars. The Serpens VLA sources are spatially distributed
into two groups; one of them located towards the NW clump of the Serpens core,
where only Class 0 and Class I protostars are found to present cm emission, and
a second group located towards the SE clump, where radio continuum sources are
associated with objects in evolutionary classes from Class 0 to Class II. This
subgrouping is similar to that found in the near IR, mid-IR and mm wavelength
regimes.Comment: 2 figures, accepted by Astronomical journa
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