Rotation intrinsic spin coupling--the parallelism description

For the Dirac particle in the rotational system, the rotation induced inertia effect is analogously treated as the modification of the "spin connection" on the Dirac equation in the flat spacetime, which is determined by the equivalent tetrad. From the point of view of parallelism description of spacetime, the obtained torsion axial-vector is just the rotational angular velocity, which is included in the "spin connection". Furthermore the axial-vector spin coupling induced spin precession is just the rotation-spin(1/2) interaction predicted by Mashhoon. Our derivation treatment is straightforward and simplified in the geometrical meaning and physical conception, however the obtained conclusions are consistent with that of the other previous work.Comment: 10 pages, no figur

Decay-Time Asymmetries at the B-Factories

Absract (Invited talk at the X DAE High Energy Physics symposium in December 1992, held at Tata Institute of Fundamental Research, Bombay)Comment: 20pages, TIFR/TH/93-1

Na2.4Al0.4Mn2.6O7 anionic redox cathode material for sodium ion batteries- a combined experimental and theoretical approach to elucidate its charge storage mechanism

Here we report the synthesis via ceramic methods of the high-performance Mn-rich Na2.4Al0.4Mn2.6O7 oxygen-redox cathode material for Na-ion batteries which we use as a testbed material to study the effects of Al substitution and subsequent Na excess in the high-capacity, anionic redox-based cathode material Na2Mn3O7. The material shows a stable electrochemical performance, with a specific capacity of 200 mAh g-1 in the 1.5 - 4.7 voltage window at C/20 and capacity retention of 90 % after 40 cycles. Using a combination of electrochemical and structural analysis together with hybrid density functional theory calculations we explain the behaviour of this material with changes in Mn/anionic redox reactions and associated O2 release reactions occurring in the material during electrochemical cycling (Na insertion/extraction) and compare these findings to Na2Mn3O7. We expect that these results will advance understanding of the effect of dopants in Mn-rich cathode materials with oxygen redox activity to pave their way towards real applications in high-performing sodium-ion battery applications

Sources of CP Violation in the Two-Higgs Doublet Model

Assuming CP violation arises solely through the Higgs potential, we develop the most general two-Higgs doublet model. There is no discrete symmetry that distinguishes the two Higgs bosons. It is assumed that an approximate global family symmetry sufficiently suppresses flavor-changing neutral scalar interactions. In addition to a CKM phase, neutral boson mixing, and superweak effects, there can be significant CP violation due to charged Higgs boson exchange. The value of $\epsilon'/\epsilon$ due to this last effect could be as large as in the standard model.Comment: 8 pages, RevTex, (appear in Phys. Rev. Lett. 73, (1994) 1762 ), CMU-HEP94-1

Isolation of Besnoitia besnoiti from infected cattle in Portugal

Abstract Besnoitia besnoiti, an obligate intracellular protozoan parasite belonging to the phylum apicomplexa, is the causative agent of bovine besnoitiosis. Besnoitiosis is responsible for significant losses in the cattle industry of Africa and Mediterranean countries due to the high morbidity rate, abortion and infertility in males. The acute stage of disease is associated with the proliferative forms (tachyzoites) and is characterized by fever, whimpery, general weakness and swelling of the superficial lymph nodes. During the following chronic stage, a huge number of cysts are formed mainly in the subcutaneous tissues. This process is non-reversible, and chronic besnoitiosis is characterized by hyper-sclerodermia, hyperkeratosis, alopecia and, in bulls, atrophy, sclerosis and focal necrosis that cause irreversible lesions in the testis. In this paper we report on the identification of large cysts in the skin of a cow and a bull in Portugal, which presented loss of hair and enlargement and pachydermis all over the body. The observation of a two-layered cyst wall within the host cell, the encapsulation of the host cell by a large outer cyst wall, and the subcutaneous localization of the cysts within the host, were characteristic for B. besnoiti. The parasites were isolated from the infected animals and successfully propagated in Vero cells without prior passages in laboratory animals. Morphological characterization of B. besnoiti tachyzoites and the amplification of the 149 bp segment from the internal transcribed spacer 1 (ITS1), aided with specific primers, confirmed the identification of B. besnoiti. Keywords: Besnoitia besnoiti; Bovine besnoitiosis; Portugal; Cyst; In vitro cell cultur

Aluminum surface layer strengthening using intense pulsedbeam radiation of substrate film system

The paper presents formation of the substrate film system (Zr-Ti-Cu/Al) by electric arc spraying of cathode having the appropriate composition. It is shown that the intense beam radiation of the substrate film system is accompanied by formation of the multi-phase state, the microhardness of which exceeds the one of pure A7 aluminum by = 4.5 times

Efeito da ferrugem e da supressão de nitrogênio no nível transcricional do gene nitrato redutase (CaNR) em Coffea arabica L.

O objetivo do trabalho é avaliar se a ferrugem do cafeeiro (Hemileia vastatrix) pode modular a resposta transcricional de um gene-chave na assimilação de nitrogênio (N), a nitrato redutase, em função da restrição do nutriente e da resposta do cultivar ao patógeno. Sabe-se que o estado nutricional da planta pode influenciar a severidade do ataque por patógenos. A ferrugem no cafeeiro é um problema recorrente em todas as regiões de cultivo, afetando desde a produtividade até a qualidade final da bebida. A despeito da importância da nutrição mineral para a produtividade e seu impacto na resposta à ferrugem, existem poucos estudos relacionados ao estabelecimento da relação molecular entre o estado nutricional do cafeeiro e resposta de defesa a patógenos. Duas cultivares ? uma resistente e uma suscetível à ferrugem do cafeeiro - foram submetidas a regimes diferenciais de N e inoculadas com H. vastatrix. A análise por qPCR do gene CaNR em três períodos pós-inoculação evidenciou padrões transcricionais distintos entre as duas cultivares - a cultivar suscetível apresentou um pico de expressão em período anterior a cultivar resistente. Este estudo preliminar evidencia que fatores genotípicos e nutricionais podem influenciar na atividade de genes relacionados ao metabolismo de N, dando suporte a futuras análises bioquímicas que auxiliem na compreensão de respostas fisiológicas e moleculares relacionadas com a interação da resposta de defesa e o estado nutricional

The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. V. Rising X-ray Emission from an Off-Axis Jet

We report the discovery of rising X-ray emission from the binary neutron star (BNS) merger event GW170817. This is the first detection of X-ray emission from a gravitational-wave source. Observations acquired with the Chandra X-ray Observatory (CXO) at t~2.3 days post merger reveal no significant emission, with L_x<=3.2x10^38 erg/s (isotropic-equivalent). Continued monitoring revealed the presence of an X-ray source that brightened with time, reaching L_x\sim 9x10^39 erg/s at ~15.1 days post merger. We interpret these findings in the context of isotropic and collimated relativistic outflows (both on- and off-axis). We find that the broad-band X-ray to radio observations are consistent with emission from a relativistic jet with kinetic energy E_k~10^49-10^50 erg, viewed off-axis with theta_obs~ 20-40 deg. Our models favor a circumbinary density n~ 0.0001-0.01 cm-3, depending on the value of the microphysical parameter epsilon_B=10^{-4}-10^{-2}. A central-engine origin of the X-ray emission is unlikely. Future X-ray observations at $t\gtrsim 100$ days, when the target will be observable again with the CXO, will provide additional constraints to solve the model degeneracies and test our predictions. Our inferences on theta_obs are testable with gravitational wave information on GW170817 from Advanced LIGO/Virgo on the binary inclination.Comment: 7 Pages, 4 Figures, ApJL, In Press. Keywords: GW170817, LV

CARB 113: Co-assembly of peptide and carbohydrate amphiphiles to generate proteoglycan mimics

Peptide amphiphiles (PA) have been used as building blocks that generate nanofibrous protein mimics through self-assembly under physiological conditions. These supramolecular structures are maintained by non-covalent interactions, such as, Pi-Pi stacking, hydrogen bonding and hydrophobic effects. The generated fibers can be further crosslinked via salt bridges thus forming hydrated systems that resemble the extracellular matrix (ECM) at structural and functional level. However, the proteins in the ECM are often presented as glycoconjugates such as glycoproteins and proteoglycans. Carbohydrate-modified PAs are just emerging as alternative or complementary building blocks able to generate closer supramolecular ECM mimics. Such PAs are challenging at synthetic, supramolecular and biofunctional level. Carbohydrates bear different â OH groups prompt to react and thus, different protections are needed for selective functionalization. Moreover, once conjugated to the PA, the carbohydrate moiety can alter its self-assembling capacity, as well as, the biofunctionality of the incorporated bioactive peptide. We therefore developed a simpler approach for generation of minimalistic proteoglycan mimics: co-assembly of short, aromatic PA and their carbohydrate analogues. The nanofibers generated by this approach have a PA core (e.g. fmoc-FF) and a carbohydrate shell (e.g. fmoc-glucosamine-6-phosphate or fmoc-glucosamine-6-sulfate). They present: 1) a higher mechanical performance than the PA single component systems; 2) an improved biofunctionality as demonstrated by our studies with growth factors (e.g. FGF2), lectins and cells. Peptide amphiphiles (PA) have been used as building blocks that generate nanofibrous protein mimics through self-assembly under physiological conditions. These supramolecular structures are maintained by non-covalent interactions, such as, Pi-Pi stacking, hydrogen bonding and hydrophobic effects. The generated fibers can be further crosslinked via salt bridges thus forming hydrated systems that resemble the extracellular matrix (ECM) at structural and functional level. However, the proteins in the ECM are often presented as glycoconjugates such as glycoproteins and proteoglycans. Carbohydrate-modified PAs are just emerging as alternative or complementary building blocks able to generate closer supramolecular ECM mimics. Such PAs are challenging at synthetic, supramolecular and biofunctional level. Carbohydrates bear different –OH groups prompt to react and thus, different protections are needed for selective functionalization. Moreover, once conjugated to the PA, the carbohydrate moiety can alter its self-assembling capacity, as well as, the biofunctionality of the incorporated bioactive peptide. We therefore developed a simpler approach for generation of minimalistic proteoglycan mimics: co-assembly of short, aromatic PA and their carbohydrate analogues. The nanofibers generated by this approach have a PA core (e.g. fmoc-FF) and a carbohydrate shell (e.g. fmoc-glucosamine-6-phosphate or fmoc-glucosamine-6-sulfate). They present: 1) a higher mechanical performance than the PA single component systems; 2) an improved biofunctionality as demonstrated by our studies with growth factors (e.g. FGF2), lectins and cells.  info:eu-repo/semantics/publishedVersio

Minimalistic supramolecular proteoglycan mimics by co-assembly of aromatic peptide and carbohydrate amphiphiles

We report the co-assembly of aromatic carbohydrate and dipeptide amphiphiles under physiological conditions as a strategy to generate minimalistic proteoglycan mimics. The resulting nanofibers present a structural, fluorenylmethoxycarbonyl-diphenylalanine (Fmoc-FF) core and a functional carbohydrate (Fmoc-glucosamine-6-sulfate or -phosphate) shell. The size, degree of bundling and mechanical properties of the assembled structures depend on the chemical nature of the carbohydrate amphiphile used. In cell culture medium, these nanofibers can further organize into supramolecular hydrogels. We demonstrate that, similar to proteoglycans, the assembled gels prolong the stability of growth factors and preserve the viability of cultured cells. Our results demonstrate that this approach can be applied to the design of extracellular matrix (ECM) substitutes for future regenerative therapies.We acknowledge the EU's H2020 and FP7 framework programmes (Forecast 668983; CHEM2NATURE 692333; THE DISCOVERIES CTR 739572; ERC AdG ComplexiTE 321266) and the Portuguese FCT (IF/00032/2013; BD/113794/2015; BPD/85790/2012; M-ERA-NET2/0001/2016 – INCIPIT; ENMed/001/2015 – CytoNanoHeal). We thank P. Frederix for his help in the FTIR measurements and M. Mullin for her help in the TEM imaging.info:eu-repo/semantics/publishedVersio