213 research outputs found
Theory of the ground state spin of the NV- center in diamond: I. Fine structure, hyperfine structure, and interactions with electric, magnetic and strain fields
The ground state spin of the negatively charged nitrogen-vacancy center in
diamond has been the platform for the recent rapid expansion of new frontiers
in quantum metrology and solid state quantum information processing. In ambient
conditions, the spin has been demonstrated to be a high precision magnetic and
electric field sensor as well as a solid state qubit capable of coupling with
nearby nuclear and electronic spins. However, in spite of its many outstanding
demonstrations, the theory of the spin has not yet been fully developed and
there does not currently exist thorough explanations for many of its
properties, such as the anisotropy of the electron g-factor and the existence
of Stark effects and strain splittings. In this work, the theory of the ground
state spin is fully developed for the first time using the molecular orbital
theory of the center in order to provide detailed explanations for the spin's
fine and hyperfine structures and its interactions with electric, magnetic and
strain fields.Comment: 12 pages, 3 figures, 3 table
On the vibron dressing in the --helicoidal macromolecular chains
We present a study of the physical properties of the vibrational excitation
in --helicoidal macromolecular chains, caused by the interaction with
acoustical and optical phonon modes. The influence of the temperature and the
basic system parameters on the vibron dressing has been analyzed by employing
the simple mean--field approach based on the variational extension of the
Lang--Firsov unitary transformation. Applied approach predicts a region in
system parameter space where one takes place an abrupt transition from
partially dressed (light and mobile) to fully dressed (immobile) vibron states.
We found that the boundary of this region depends on system temperature and
type of bond among structural elements in the macromolecular chain.Comment: 22 pages, 12 figures, title changed, the interaction with optical
phonon modes jointly with acoustical ones added, consideration significantly
enlarged, references added, the paper develops the results of
arxiv:1210.3918, accepted for publication in Chinese Physics
Comprehensive analysis of the 9p21 region in neuroblastoma suggests a role for genes mapping to 9p21–23 in the biology of favourable stage 4 tumours
Chromosome 9p21 is frequently deleted in many cancers. Previous reports have indicated that 9p21 LOH is an uncommon finding in neuroblastoma (NB), a tumour of childhood. We have performed an extensive analysis of 9p21 and genes located in this region (cyclin-dependent kinase inhibitor 2A – CDKN2A/p16INK4a, CDKN2A/p14ARF, CDKN2B/p15INK4b, MTAP, interferon α and β cluster). LOH was detected in 16.4% of 177 NB. The SRO was identified between markers D9S1751 and D9S254, at 9p21–23, a region telomeric to the CDKN2A and MTAP genes. A significantly better overall and progression-free survival was detected in stage 4 patients displaying 9p21–23 LOH. Hemizygous deletion of the region harbouring the CDKN2A and CDKN2B loci was identified in two tumours by means of fluorescent in situ hybridisation and MTAP was present by immunostaining in all but one tumour analysed. The transcriptional profile of tumours with 9p21–23 LOH was compared to that of NB displaying normal 9p21–23 status by means of oligonucleotide microarrays. Four of the 363 probe sets downregulated in tumours with 9p21–23 LOH were encoded by genes mapping to 9p22–24. The only well-characterised transcript among them was nuclear factor I-B3. Our results suggest a role for genes located telomeric of 9p21 in good risk NB
An Induced Hypersensitive-Like Response Limits Expression of Foreign Peptides via a Recombinant TMV-Based Vector in a Susceptible Tobacco
BACKGROUND: By using tobacco mosaic virus (TMV)-based vectors, foreign epitopes of the VP1 protein from food-and-month disease virus (FMDV) could be fused near to the C-terminus of the TMV coat protein (CP) and expressed at high levels in susceptible tobacco plants. Previously, we have shown that the recombinant TMV vaccines displaying FMDV VP1 epitopes could generate protection in guinea pigs and swine against the FMDV challenge. Recently, some recombinant TMV, such as TMVFN20 that contains an epitope FN20 from the FMDV VP1, were found to induce local necrotic lesions (LNL) on the inoculated leaves of a susceptible tobacco, Nicotiana tabacum Samsun nn. This hypersensitive-like response (HLR) blocked amplification of recombinant TMVFN20 in tobacco and limited the utility of recombinant TMV vaccines against FMDV. METHODOLOGY/PRINCIPAL FINDINGS: Here we investigate the molecular mechanism of the HLR in the susceptible Samsun nn. Histochemical staining analyses show that these LNL are similar to those induced in a resistant tobacco Samsun NN inoculated with wild type (wt) TMV. The recombinant CP subunits are specifically related to the HLR. Interestingly, this HLR in Samsun nn (lacking the N/N'-gene) was able to be induced by the recombinant TMV at both 25°C and 33°C, whereas the hypersensitive response (HR) in the resistant tobacco plants induced by wt TMV through the N/N'-gene pathways only at a permissive temperature (below 30°C). Furthermore, we reported for the first time that some of defense response (DR)-related genes in tobacco were transcriptionally upregulated during HLR. CONCLUSIONS: Unlike HR, HLR is induced in the susceptible tobacco through N/N'-gene independent pathways. Induction of the HLR is associated with the expression of the recombinant CP subunits and upregulation of the DR-related genes
“What you don't know can't hurt you”: The right to know and the Shetland Island oil spill
This paper, an account of the Shetland Islands oil spill (1993), examines the public health controversies surrounding the spill and the clean- up response. It critically examines the risk management policies of both the United Kingdom and the Shetland Islands Public Health Office, and suggests that the withholding of critical information contributed to increased anxiety and suspicion among the disaster victims. In an attempt to reassure the victims, the policies contributed to an increased air of uncertainty. It is further argued that the withholding of information prevents those who are at greatest risk from participating in critical decisions that may affect their health and livelihoods and asserts that a right- to- know policy is a critical first step in risk management practices .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44488/1/10745_2005_Article_BF01191651.pd
A História da Alimentação: balizas historiográficas
Os M. pretenderam traçar um quadro da História da Alimentação, não como um novo ramo epistemológico da disciplina, mas como um campo em desenvolvimento de práticas e atividades especializadas, incluindo pesquisa, formação, publicações, associações, encontros acadêmicos, etc. Um breve relato das condições em que tal campo se assentou faz-se preceder de um panorama dos estudos de alimentação e temas correia tos, em geral, segundo cinco abardagens Ia biológica, a econômica, a social, a cultural e a filosófica!, assim como da identificação das contribuições mais relevantes da Antropologia, Arqueologia, Sociologia e Geografia. A fim de comentar a multiforme e volumosa bibliografia histórica, foi ela organizada segundo critérios morfológicos. A seguir, alguns tópicos importantes mereceram tratamento à parte: a fome, o alimento e o domínio religioso, as descobertas européias e a difusão mundial de alimentos, gosto e gastronomia. O artigo se encerra com um rápido balanço crítico da historiografia brasileira sobre o tema
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