18,372 research outputs found
Stable splitting of bivariate spline spaces by Bernstein-Bézier methods
We develop stable splitting of the minimal determining sets for the spaces of bivariate C1 splines on triangulations, including a modified Argyris space, Clough-Tocher, Powell-Sabin and quadrilateral macro-element spaces. This leads to the stable splitting of the corresponding bases as required in Böhmer's method for solving fully nonlinear elliptic PDEs on polygonal domains
Two Purified Domains of Telomerase Reverse Transcriptase Reconstitute Sequence-Specific Interactions with RNA
Telomerase reverse transcriptase (TERT) and telomerase RNA (TER) function together to create a uniquely specialized polymerase. Here we have described for the first time domains of bacterially expressed Tetrahymena TERT that interacted directly with TER in the absence of assembly chaperones. We used quantitative binding assays to define TER sequence requirements for recognition by the high affinity RNA binding domain and an independent N-terminal RNA interaction domain. The TERT RNA binding domain and N-terminal RNA interaction domain had distinct, nonoverlapping requirements for TER sequence and structure that together accounted for all of the sites of TER contact inferred for full-length TERT. The TER residues important for TERT binding are only a subset of the residues required for catalytic activity. Our findings demonstrate telomerase functional specialization by an elaborate ribonucleoprotein architecture physically separable from the active site
Deacidification of palm oil using solvent extraction integrated with membrane technology
In this work, the efficiency of crude palm oil (CPO) deacidification using solvent extraction integrated with membrane technology is studied. Different solvents including ethanol, hexane and methanol were selected to extract the palmitic acid from model fatty system in the model fatty system to solvent ratio of 1:2. Experimental results showed that ethanol was the best solvent to extract palmitic acid from the model fatty system, recording about 65.5% fatty acid reduction in the model fatty system. Three commercial solvent resistant nanofiltration (SRNF) membranes (SolSep NF010206, NF030306, and NF030705) were then selected to examine their respective performance in recovering ethanol from palmitic acid-rich ethanol solvent. The results revealed that the combination of solvent extraction and membrane technology is remarkable simple and waste-free approach to overcome major drawbacks of conventional refinery operation
Current-oscillator correlation and Fano factor spectrum of quantum shuttle with finite bias voltage and temperature
A general master equation is derived to describe an electromechanical
single-dot transistor in the Coulomb blockade regime. In the equation, Fermi
distribution functions in the two leads are taken into account, which allows
one to study the system as a function of bias voltage and temperature of the
leads. Furthermore, we treat the coherent interaction mechanism between
electron tunneling events and the dynamics of excited vibrational modes.
Stationary solutions of the equation are numerically calculated. We show
current through the oscillating island at low temperature appears step like
characteristics as a function of the bias voltage and the steps depend on mean
phonon number of the oscillator. At higher temperatures the current steps would
disappear and this event is accompanied by the emergence of thermal noise of
the charge transfer. When the system is mainly in the ground state, zero
frequency Fano factor of current manifests sub-Poissonian noise and when the
system is partially driven into its excited states it exhibits super-Poissonian
noise. The difference in the current noise would almost be removed for the
situation in which the dissipation rate of the oscillator is much larger than
the bare tunneling rates of electrons.Comment: 14 pages, 8 figure
An immunotherapy survivor population: health-related quality of life and toxicity in patients with metastatic melanoma treated with immune checkpoint inhibitors
© The Author(s) 2019. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Purpose The immune checkpoint inhibitors (ICIs) have resulted in subgroups of patients with metastatic melanoma achievinghigh-quality durable responses. Metastatic melanoma survivors are a new population in the era of cancer survivorship. The aimofthis study was to evaluate metastatic melanoma survivors in terms of health-related quality of life (HRQoL), immune-relatedadverse events (irAEs) and exposure to immunosuppressive agents in a large single centre in the UK.Methods We defined the survivor population as patients with a diagnosis of metastatic melanoma who achieved a durableresponse to an ICI and had been followed-up for a minimum of 12 months from initiation of ICI without disease progression.HRQoL was assessed using SF-36. Electronic health records were accessed to collect data on demographics, treatments, irAEsand survival. HRQoL data was compared with two norm-based datasets.Results Eighty-four metastatic melanoma survivors were eligible and 87% (N = 73) completed the SF-36. ICI-related toxicity ofany grade occurred in 92%of patients and 43%had experienced a grade 3 or 4 toxicity. Almost half (49%) of the patients requiredsteroids for the treatment of ICI-related toxicity, whilst 14% required treatment with an immunosuppressive agent beyondsteroids.Melanoma survivors had statistically significant lower HRQoL scores with regard to physical, social and physical rolefunctioning and general health compared with the normative population. There was a trend towards inferior scores in patientswith previous exposure to ipilimumab compared with those never exposed to ipilimumab.Conclusions Our results show that metastatic melanoma survivors have potentially experienced significant ICI-related toxicityand experience significant impairments in specific HRQoL domains. Future service planning is required to meet this population’sunique survivorship needs.Peer reviewe
Bivariate spline interpolation with optimal approximation order
Let be a triangulation of some polygonal domain f c R2 and let S9 (A) denote the space of all bivariate polynomial splines of smoothness r and degree q with respect to A. We develop the first Hermite-type interpolation scheme for S9 (A), q >_ 3r + 2, whose approximation error is bounded above by Kh4+i, where h is the maximal diameter of the triangles in A, and the constant K only depends on the smallest angle of the triangulation and is independent of near-degenerate edges and nearsingular vertices. Moreover, the fundamental functions of our scheme are minimally supported and form a locally linearly independent basis for a superspline subspace of Sr, (A). This shows that the optimal approximation order can be achieved by using minimally supported splines. Our method of proof is completely different from the quasi-interpolation techniques for the study of the approximation power of bivariate splines developed in [71 and [181
On the Possible Enhancement of the Magnetic Field by Neutrino Reemission Processes in the Mantle of a Supernova
URCA neutrino reemission processes under the conditions in the mantle of a
supernova with a strong toroidal magnetic field are investigated. It is shown
that parity violation in these processes can be manifested macroscopically as a
torque that rapidly spins up the region of the mantle occupied by such a field.
Neutrino spin-up of the mantle can strongly affect the mechanism of further
generation of the toroidal field, specifically, it can enhance the field in a
small neighborhood of the rigid-body-rotating core of the supernova remnant.Comment: 8 pages, late
Study of the thermal stress in a Pb-free half-bump solder joint under current stressing
The thermal stress in a Sn3.5Ag1Cu half-bump solder joint under a 3.82×108 A/m2 current stressing was analyzed using a coupled-field simulation. Substantial thermal stress accumulated around the Al-to-solder interface, especially in the Ni+(Ni,Cu)3Sn4 layer, where a maximal stress of 138 MPa was identified. The stress gradient in the Ni layer was about 1.67×1013 Pa/m, resulting in a stress migration force of 1.82×10-16 N, which is comparable to the electromigration force, 2.82×10-16 N. Dissolution of the Ni+(Ni,Cu)3Sn4 layer, void formation with cracks at the anode side, and extrusions at the cathode side were observe
The VAST Survey - IV. A wide brown dwarf companion to the A3V star Delphini
We report the discovery of a wide co-moving substellar companion to the
nearby ( pc) A3V star Delphini based on imaging and
follow-up spectroscopic observations obtained during the course of our
Volume-limited A-Star (VAST) multiplicity survey. Del was observed over
a five-year baseline with adaptive optics, revealing the presence of a
previously-unresolved companion with a proper motion consistent with that of
the A-type primary. The age of the Del system was estimated as
Myr based on the position of the primary on the colour-magnitude
and temperature-luminosity diagrams. Using intermediate-resolution
near-infrared spectroscopy, the spectrum of Del B is shown to be
consistent with a mid-L dwarf (L), at a temperature of K.
Combining the measured near-infrared magnitude of Del B with the
estimated temperature leads to a model-dependent mass estimate of
M, corresponding to a mass ratio of . At a
projected separation of au, Del B is among the most
widely-separated and extreme-mass ratio substellar companions to a
main-sequence star resolved to-date, providing a rare empirical constraint of
the formation of low-mass ratio companions at extremely wide separations.Comment: 12 pages, 11 figures, accepted for publication in the Monthly Notices
of the Royal Astronomical Society, 2014 September 25. Revised to incorporate
typographical errors noted during the proofing proces
Spin-valley phase diagram of the two-dimensional metal-insulator transition
Using symmetry breaking strain to tune the valley occupation of a
two-dimensional (2D) electron system in an AlAs quantum well, together with an
applied in-plane magnetic field to tune the spin polarization, we independently
control the system's valley and spin degrees of freedom and map out a
spin-valley phase diagram for the 2D metal-insulator transition. The insulating
phase occurs in the quadrant where the system is both spin- and
valley-polarized. This observation establishes the equivalent roles of spin and
valley degrees of freedom in the 2D metal-insulator transition.Comment: 4 pages, 2 figure
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