630 research outputs found
Ethics of primate use
This article provides an overview of the ethical issues raised by the use of
non-human primates (NHPs) in research involving scientific procedures which
may cause pain, suffering, distress or lasting harm. It is not an exhaustive
review of the literature and views on this subject, and it does not present
any conclusions about the moral acceptability or otherwise of NHP research.
Rather the aim has been to identify the ethical issues involved and to
provide guidance on how these might be addressed, in particular by carefully
examining the scientific rationale for NHP use, implementing fully the 3Rs
principle of Russell and Burch (1959) and applying a robust "harm-benefit
assessment" to research proposals involving NHPs
Localized inhibition of protein phosphatase 1 by NUAK1 promotes spliceosome activity and reveals a MYC-sensitive feedback control of transcription.
Deregulated expression of MYC induces a dependence on the NUAK1 kinase, but the molecular mechanisms underlying this dependence have not been fully clarified. Here, we show that NUAK1 is a predominantly nuclear protein that associates with a network of nuclear protein phosphatase 1 (PP1) interactors and that PNUTS, a nuclear regulatory subunit of PP1, is phosphorylated by NUAK1. Both NUAK1 and PNUTS associate with the splicing machinery. Inhibition of NUAK1 abolishes chromatin association of PNUTS, reduces spliceosome activity, and suppresses nascent RNA synthesis. Activation of MYC does not bypass the requirement for NUAK1 for spliceosome activity but significantly attenuates transcription inhibition. Consequently, NUAK1 inhibition in MYC-transformed cells induces global accumulation of RNAPII both at the pause site and at the first exon-intron boundary but does not increase mRNA synthesis. We suggest that NUAK1 inhibition in the presence of deregulated MYC traps non-productive RNAPII because of the absence of correctly assembled spliceosomes
The relevance of outsourcing and leagile strategies in performance optimization of an integrated process planning and scheduling
Over the past few years growing global competition has forced the manufacturing industries to upgrade their old production strategies with the modern day approaches. As a result, recent interest has been developed towards finding an appropriate policy that could enable them to compete with others, and facilitate them to emerge as a market winner. Keeping in mind the abovementioned facts, in this paper the authors have proposed an integrated process planning and scheduling model inheriting the salient features of outsourcing, and leagile principles to compete in the existing market scenario. The paper also proposes a model based on leagile principles, where the integrated planning management has been practiced. In the present work a scheduling problem has been considered and overall minimization of makespan has been aimed. The paper shows the relevance of both the strategies in performance enhancement of the industries, in terms of their reduced makespan. The authors have also proposed a new hybrid Enhanced Swift Converging Simulated Annealing (ESCSA) algorithm, to solve the complex real-time scheduling problems. The proposed algorithm inherits the prominent features of the Genetic Algorithm (GA), Simulated Annealing (SA), and the Fuzzy Logic Controller (FLC). The ESCSA algorithm reduces the makespan significantly in less computational time and number of iterations. The efficacy of the proposed algorithm has been shown by comparing the results with GA, SA, Tabu, and hybrid Tabu-SA optimization methods
Ce-L3-XAS study of the temperature dependence of the 4f occupancy in the Kondo system Ce2Rh3Al9
We have used temperature dependent x-ray absorption at the Ce-L3 edge to
investigate the recently discovered Kondo compound Ce2Rh3Al9. The systematic
changes of the spectral lineshape with decreasing temperature are analyzed and
found to be related to a change in the occupation number, n_f, as the
system undergoes a transition into a Kondo state. The temperature dependence of
indicates a characteristic temperature of 150K, which is clearly related
with the high temperature anomaly observed in the magnetic susceptibility of
the same system. The further anomaly observed in the resistivity of this system
at low temperature (ca. 20K) has no effect on n_f and is thus not of Kondo
origin.Comment: 7 pages, three figures, submitted to PR
High temperature superconductivity (Tc onset at 34K) in the high pressure orthorhombic phase of FeSe
We have studied the structural and superconducting properties of tetragonal
FeSe under pressures up to 26GPa using synchrotron radiation and diamond anvil
cells. The bulk modulus of the tetragonal phase is 28.5(3)GPa, much smaller
than the rest of Fe based superconductors. At 12GPa we observe a phase
transition from the tetragonal to an orthorhombic symmetry. The high pressure
orthorhombic phase has a higher Tc reaching 34K at 22GPa.Comment: 15 pages, 4 figure
Maternal age effect and severe germ-line bottleneck in the inheritance of human mitochondrial DNA
The manifestation of mitochondrial DNA (mtDNA) diseases depends on the frequency of heteroplasmy (the presence of several alleles in an individual), yet its transmission across generations cannot be readily predicted owing to a lack of data on the size of the mtDNA bottleneck during oogenesis. For deleterious heteroplasmies, a severe bottleneck may abruptly transform a benign (low) frequency in a mother into a disease-causing (high) frequency in her child. Here we present a high-resolution study of heteroplasmy transmission conducted on blood and buccal mtDNA of 39 healthy mother–child pairs of European ancestry (a total of 156 samples, each sequenced at ∼20,000× per site). On average, each individual carried one heteroplasmy, and one in eight individuals carried a disease-associated heteroplasmy, with minor allele frequency ≥1%. We observed frequent drastic heteroplasmy frequency shifts between generations and estimated the effective size of the germ-line mtDNA bottleneck at only ∼30–35 (interquartile range from 9 to 141). Accounting for heteroplasmies, we estimated the mtDNA germ-line mutation rate at 1.3 × 10−8 (interquartile range from 4.2 × 10−9 to 4.1 × 10−8) mutations per site per year, an order of magnitude higher than for nuclear DNA. Notably, we found a positive association between the number of heteroplasmies in a child and maternal age at fertilization, likely attributable to oocyte aging. This study also took advantage of droplet digital PCR (ddPCR) to validate heteroplasmies and confirm a de novo mutation. Our results can be used to predict the transmission of disease-causing mtDNA variants and illuminate evolutionary dynamics of the mitochondrial genome
The nonlinear time-dependent response of isotactic polypropylene
Tensile creep tests, tensile relaxation tests and a tensile test with a
constant rate of strain are performed on injection-molded isotactic
polypropylene at room temperature in the vicinity of the yield point. A
constitutive model is derived for the time-dependent behavior of
semi-crystalline polymers. A polymer is treated as an equivalent network of
chains bridged by permanent junctions. The network is modelled as an ensemble
of passive meso-regions (with affine nodes) and active meso-domains (where
junctions slip with respect to their positions in the bulk medium with various
rates). The distribution of activation energies for sliding in active
meso-regions is described by a random energy model. Adjustable parameters in
the stress--strain relations are found by fitting experimental data. It is
demonstrated that the concentration of active meso-domains monotonically grows
with strain, whereas the average potential energy for sliding of junctions and
the standard deviation of activation energies suffer substantial drops at the
yield point. With reference to the concept of dual population of crystalline
lamellae, these changes in material parameters are attributed to transition
from breakage of subsidiary (thin) lamellae in the sub-yield region to
fragmentation of primary (thick) lamellae in the post-yield region of
deformation.Comment: 29 pages, 12 figure
Diquat Derivatives: Highly Active, Two-Dimensional Nonlinear Optical Chromophores with Potential Redox Switchability
In this article, we present a detailed study of structure−activity relationships in diquaternized 2,2′-bipyridyl (diquat) derivatives. Sixteen new chromophores have been synthesized, with variations in the amino electron donor substituents, π-conjugated bridge, and alkyl diquaternizing unit. Our aim is to combine very large, two-dimensional (2D) quadratic nonlinear optical (NLO) responses with reversible redox chemistry. The chromophores have been characterized as their PF_6^− salts by using various techniques including electronic absorption spectroscopy and cyclic voltammetry. Their visible absorption spectra are dominated by intense π → π^* intramolecular charge-transfer (ICT) bands, and all show two reversible diquat-based reductions. First hyperpolarizabilities β have been measured by using hyper-Rayleigh scattering with an 800 nm laser, and Stark spectroscopy of the ICT bands affords estimated static first hyperpolarizabilities β_0. The directly and indirectly derived β values are large and increase with the extent of π-conjugation and electron donor strength. Extending the quaternizing alkyl linkage always increases the ICT energy and decreases the E_(1/2) values for diquat reduction, but a compensating increase in the ICT intensity prevents significant decreases in Stark-based β_0 responses. Nine single-crystal X-ray structures have also been obtained. Time-dependent density functional theory clarifies the molecular electronic/optical properties, and finite field calculations agree with polarized HRS data in that the NLO responses of the disubstituted species are dominated by ‘off-diagonal’ β_(zyy) components. The most significant findings of these studies are: (i) β_0 values as much as 6 times that of the chromophore in the technologically important material (E)-4′-(dimethylamino)-N-methyl-4-stilbazolium tosylate; (ii) reversible electrochemistry that offers potential for redox-switching of optical properties over multiple states; (iii) strongly 2D NLO responses that may be exploited for novel practical applications; (iv) a new polar material, suitable for bulk NLO behavior
Upper critical field, lower critical field and critical current density of FeTe0.60Se0.40 single crystal
The transport and magnetic studies are performed on high quality
FeTe0.60Se0.40 single crystals to determine the upper critical fields (Hc2),
lower critical field (Hc1) and the Critical current density (Jc). The value of
upper critical field Hc2 are very large, whereas the activation energy as
determined from the slope of the Arrhenius plots are was found to be lower than
that in the FeAs122 superconductor. The lower critical field was determined in
ab direction and c direction of the crystal, and was found to have a anisotropy
of 'gamma'{=(Hc1//c) / (Hc1//b)} ~ 4. The magnetic isotherms measured up to 12
Tesla shows the presence of fishtail behavior. The critical current densities
at 1.8K of the single crystal was found to almost same in both ab and c
direction as 1X105 Amp/cm2 in low field regime.Comment: 9 pages, 6 figure
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