Corneal endothelial response to induced myopia in the chicken

Purpose: To investigate the role of corneal endothelial surface enlargement in the chicken myopia model in inducing corneal endothelial changes. Methods: Lid suture was performed on one eye of 1-day-old cockerels. Five chickens were killed at 1 week, and four chickens killed at each of 3 weeks, 6 weeks, and 10 weeks postnatal. The endothelial morphology was obtained by flat mounting the endothelial surface and the subsequent digitisation. Comparisons were undertaken between the control unsutured eye and the lid-sutured eye endothelium, and between the central endothelial areas compared to the peripheral endothelial areas in both the myopic and the normal corneas. Calculation of the contribution to the endothelial change by hypertrophy and mitosis were calculated using Bahn's formula. Results: Total endothelial surface area increased significantly over time in the myopic model compared to control eyes but the mean cell area of endothelial cells remained the same for both the enlarged myopic endothelial surface area and in the normal controls. Sampling from the central and the peripheral corneal endothelial surface also disclosed no difference. The mean cell area did increase steadily with age but was the same for both normal and myopic corneas. Conclusions: It would appear that there are equal contributions from hypertrophy and mitosis in the myopic group and the normal corneal group with a slightly increasing trend towards mitotic activity in the myopic corneal endothelial layer.

Universal state inversion and concurrence in arbitrary dimensions

Wootters [Phys. Rev. Lett. 80, 2245 (1998)] has given an explicit formula for the entanglement of formation of two qubits in terms of what he calls the concurrence of the joint density operator. Wootters's concurrence is defined with the help of the superoperator that flips the spin of a qubit. We generalize the spin-flip superoperator to a universal inverter, which acts on quantum systems of arbitrary dimension, and we introduce the corresponding generalized concurrence for joint pure states of D-1 X D-2 bipartite quantum systems. We call this generalized concurrence the I concurrence to emphasize its relation to the universal inverter. The universal inverter, which is a positive, but not completely positive superoperator, is closely related to the completely positive universal-NOT superoperator, the quantum analogue of a classical NOT gate. We present a physical realization of the universal-NOT Superoperator.

Role of cytokine gene polymorphisms in acute rejection and renal impairment after liver transplantation

Although immunosuppressive regimens are effective, rejection occurs in up to 50% of patients after orthotopic liver transplantation (OLT), and there is concern about side effects from long-term therapy. Knowledge of clinical and immunogenetic variables may allow tailoring of immunosuppressive therapy to patients according to their potential risks. We studied the association between transforming growth factor-beta, interleukin-10, and tumor necrosis factor alpha (TNF-alpha) gene polymorphisms and graft rejection and renal impairment in 121 white liver transplant recipients. Clinical variables were collected retrospectively, and creatinine clearance was estimated using the formula of Cockcroft and Gault. Biallelic polymorphisms were detected using polymerase chain reaction-based methods. Thirty-seven of 121 patients (30.6%) developed at least 1 episode of rejection. Multivariate analysis showed that Child-Pugh score (P =.001), immune-mediated liver disease (P =.018), normal pre-OLT creatinine clearance (P =.037), and fewer HLA class 1 mismatches (P =.038) were independently associated with rejection, Renal impairment occurred in 80% of patients and was moderate or severe in 39%, Clinical variables independently associated with renal impairment were female sex (P =.001), pre-OLT renal dysfunction (P =.0001), and a diagnosis of viral hepatitis (P =.0008), There was a significant difference in the frequency of TNF-alpha -308 alleles among the primary liver diseases. After adjustment for potential confounders and a Bonferroni correction, the association between the TNF-alpha -308 polymorphism and graft rejection approached significance (P =.06). Recipient cytokine genotypes do not have a major independent role in graft rejection or renal impairment after OLT, Additional studies of immunogenetic factors require analysis of large numbers of patients with appropriate phenotypic information to avoid population stratification, which may lead to inappropriate conclusions.

Twisting and planarization in push-pull ethylenes

As determined by X-ray crystallography, Meldrum's acid derivatives 8–19 feature dihedral angles around the central CC double bonds between 3 and 83°. Hydrogen bonds between substituents RHN and the carbonyl groups favour near-planarity. Sterically demanding substituents favour large dihedral angles and zwitterionic structures as in formula 20. AM1 calculations of the structures are in excellent agreement with the experimental X-ray data, provided a dielectric field is incorporated (?= 40). This can be ascribed to the highly polar (zwitterionic) nature of the molecules. It is further predicted that all these molecules, including those that are stabilised in a planar form by intramolecular hydrogen bonds, undergo rapid rotation about the central CC bonds at room temperature. DFT calculations incorporating a dielectric field model (PCM) are in excellent agreement with the near-perpendicular arrangement of the alkene moiety in 19.

A theoretical study of the origin of rotational barriers in push-pull ethylenes

Using the B3LYP/6-31G* ab initio method, we have studied the rotation about the C=C bonds in 15 push-pull ethylenes of the general formula (X,Y)C=C(CHO)(2) [X, Y = NH2, NHCH3, N(CH3)(2), OCH3, SCH3] in the gas phase. Two stationary points (minimum and transition state) were located for all compounds. The geometry, dipole moments, natural bond orbital atomic charges, as well as the rotational barriers were examined. The torsion angle 0 depends essentially on the presence or absence of intramolecular hydrogen bonds, and the barrier is a function of the torsion angle. (C) 2002 Elsevier Science B.V. All rights reserved.

Shear stress and sediment transport calculations for swash zone modelling

It is shown that the observed difference in sediment transporting efficiency by the swash uprush, compared with the downrush, could be mainly due to greater bed shear stress for a given velocity in the more abruptly accelerated uprush. The bed shear stress generated by an arbitrary free stream velocity time series is modelled in terms of usual wave boundary layer models plus a phase lead (phi(tau) of the bed shear stress compared with the free stream velocity at the peak frequency. With this approach, the total transport amounts in uprush and downrush can be modelled satisfactorily with the same sediment transport formula, without the need for different uprush and downrush coefficients. While the adaptation of sediment transport formulae from steady flow can thus lead to the right total amounts of sediment moved by this method, the timing of the instantaneous sediment transport rates are probably not accurately modelled due to the highly unsteady nature of the swash and the presence of pre-suspended sediment in the uprush. Nevertheless, the proposed method is a useful intermediate step before we have a complete understanding of sediment transport under very rapid accelerations and of the relative contribution of pre-suspended sediment to the onshore sediment transport in swash zones. (C) 2002 Published by Elsevier Science B.V.

Shear stress and sediment transport calculations for sheet flow under waves

A simple method is provided for calculating transport rates of not too fine (d(50) greater than or equal to 0.20 mm) sand under sheet flow conditions. The method consists of a Meyer-Peter-type transport formula operating on a time-varying Shields parameter, which accounts for both acceleration-asymmetry and boundary layer streaming. While velocity moment formulae, e.g.., = Constant x calibrated against U-tube measurements, fail spectacularly under some real waves (Ribberink, J.S., Dohmen-Janssen, C.M., Hanes, D.M., McLean, S.R., Vincent, C., 2000. Near-bed sand transport mechanisms under waves. Proc. 27th Int. Conf. Coastal Engineering, Sydney, ASCE, New York, pp. 3263-3276, Fig. 12), the new method predicts the real wave observations equally well. The reason that the velocity moment formulae fail under these waves is partly the presence of boundary layer streaming and partly the saw-tooth asymmetry, i.e., the front of the waves being steeper than the back. Waves with saw-tooth asymmetry may generate a net landward sediment transport even if = 0, because of the more abrupt acceleration under the steep front. More abrupt accelerations are associated with thinner boundary layers and greater pressure gradients for a given velocity magnitude. The two real wave effects are incorporated in a model of the form Q(s)(t) = Q(s)[theta(t)] rather than Q(S)(t) = Q(S)[u(infinity)(t)], i.e., by expressing the transport rate in terms of an instantaneous Shields parameter rather than in terms of the free stream velocity, and accounting for both streaming and accelerations in the 0(t) calculations. The instantaneous friction velocities u(*)(t) and subsequently theta(t) are calculated as follows. Firstly, a linear filter incorporating the grain roughness friction factor f(2.5) and a phase angle phi(tau) is applied to u(infinity)(t). This delivers u(*)(t) which is used to calculate an instantaneous grain roughness Shields parameter theta(2.5)(t). Secondly, a constant bed shear stress is added which corresponds to the streaming related bed shear stress -rho ($) over bar((u) over tilde(w) over tilde)(infinity) . The method can be applied to any u(infinity)(t) time series, but further experimental validation is recommended before application to conditions that differ strongly from the ones considered below. The method is not recommended for rippled beds or for sheet flow with typical prototype wave periods and d(50) < 0.20 turn. In such scenarios, time lags related to vertical sediment movement become important, and these are not considered by the present model. (C) 2002 Elsevier Science B.V. All rights reserved.

A suite of novel allenes from Australian melolonthine scarab beetles. Structure, synthesis, and stereochemistry

A suite of allenic hydrocarbons, previously unknown as a molecular class from insects, has been characterized from several Australian melolonthine scarab beetles. The allenes are represented by the formula CH3(CH2)nCH=.=CH(CH2)(7)CH3 with n being 11-15, 17 and 19, and thus, all have Delta(9,10)-unsaturation. These structures have been confirmed by syntheses and comparisons of spectral and chromatographic properties with those of the natural components. The enantiomers of (+/-)-Delta(9,10)-tricosadiene and Delta(9,10)-pentacosadiene were separable on a modified beta-cyclodextrin column (gas chromatography), and the natural Delta(9,10)-tricosadiene (n = 11) and Delta(9,10)-pentacosadiene (n = 13) were shown to be of >85% ee. Syntheses of nonracemic allenes of known predominating chirality were acquired using both organotin chemistry and sulfonylhydrazine intermediates, and comparisons then demonstrated that the natural allenes were predominantly (R)-configured.

Synthesis and characterization of mono- and bis-ligand zinc(II) and cadmium(II) complexes of the di-2-pyridylketone Schiff base of S-benzyl dithiocarbazate (Hdpksbz) and the X-ray crystal structures of the [Zn(dpksbz)2] and [Cd(dpksbz)NCS]2 complexes

New mono- and bis-chelated zinc(II) and cadmium(II) complexes of formula, [M(dpksbz)NCS] (dpksbz = anionic form of the di-2-pyridylketone Schiff base of S-benzyldithiocarbazate) and [M(dpksbz)(2)] (M = Zn-II, Cd-II) have been prepared and characterized. The structure of the bis-ligand complex, [Zn(dpksbZ)(2)] has been determined by X-ray diffraction. The complex has a distorted octahedral geometry in which the ligands are coordinated to the zinc(II) ion as uninegatively charged tridentate chelates via the thiolate sulfur atoms, the azomethine nitrogen atoms and the pyridine nitrogen atoms. The distortion from a regular octahedral geometry is attributed to the restricted bite angles of the Schiff base ligands. X-ray structural analysis shows that the [Cd(dpksbz)NCS](2) complex is a centrosymmetric dimer in which each of the cadmium(II) ions adopts a five-coordinate, approximately square-pyramidal configuration with the Schiff base acting as a tetradentate chelating agent coordinating a cadmium(II) ion via one of the pyridine nitrogen atoms, the azomethine nitrogen atom and the thiolate sulfur atom; the second pyridine nitrogen atom is coordinated to the other cadmium(II) ion of the dimer. The fifth coordination position around each cadmium(II) is occupied by an N-bonded thiocyanate ligand. (C) 2003 Elsevier Science Ltd. All rights reserved.

The preparation of zinc(II) and cadmium(II) complexes of the pentadentate N3S2 ligand formed from 2,6-diacetylpyridine and S-benzyldithiocarbazate (H2SNNNS) and the X-ray crystal structure of the novel dimeric [Zn2(SNNNS)2] complex

The pentadentate chelating agent, 2,6-diacetylpyridinebis(S-benzyldithiocarbazate) (H2SNNNS) reacts with zinc(II) and cadmium(II) ions forming stable complexes of empirical formula, [M(SNNNS)] (M=Zn2+, Cd2+; SNNNS2 =doubly deprotonated anionic form of the Schiff base). These complexes have been characterized by a variety of physico-chemical techniques. IR and H-1 NMR spectral evidence indicate that the Schiff base coordinates to the zinc(II) and cadmium(II) ions via the pyridine nitrogen atoms, the azomethine nitrogen atoms and the mercaptide sulfur atoms. The crystal and molecular structure of the zinc(II) complex has been determined by X-ray diffraction. The complex is a dimer in which the pyridine nitrogen atom,the azomethine nitrogen atom and the thiolate sulfur atom from one ligand coordinate to one of the zinc(II) ions whereas the azomethine and thiolate sulfur atoms from another ligand complete pentacoordination around the zinc(II) ion, the ligands being coordinated in their deprotonated forms. The coordination geometry about each zinc(II) can be considered as intermediate between a square-pyramid and trigonal-bipyramid. The cadmium(II) complex is also assigned with a dimeric structure. (C) 2003 Elsevier Ltd. All rights reserved.

Boletim eletr??nico de bibliografias especializadas: igualdade de g??nero

A 2?? edi????o de 2013 do Boletim Eletr??nico de Bibliografias Especializadas destaca o tema Igualdade de G??nero. O documento traz indica????es de pu-blica????es do acervo da Biblioteca Graciliano Ramos/ENAP com reflex??es acerca das desi-gualdades entre homens e mulheres e suas consequ??ncias ?? sociedade. O objetivo ?? dar publicidade a esses materiais, visando a con-tribuir para uma melhor compreens??o do com-plexo cen??rio de defini????o das prioridades p??blicas e da formula????o de pol??ticas p??blicas governamentais comprometidas com a pers-pectiva de g??nero, em seus diversos aspectos. De acordo com a Organiza????o das Na????es Unidas para a Educa????o, a Ci??ncia e a Cultura (Unesco), os direitos das mulheres devem ser entendidos como direitos humanos e cultu-rais fundamentais. J?? a Pol??tica Nacional para as Mulheres, coordenada pela Secre-taria Especial de Pol??ticas para as Mulhe-res (SPM), da Presid??ncia da Rep??blica, tem como pressupostos e princ??pios a equi-dade, a autonomia das mulheres, a laicida-de do Estado, a universalidade das pol??ti-cas, a justi??a social, a transpar??ncia dos atos p??blicos, a participa????o e o controle social.

O acordo de Vancouver

Este caso relata a formula????o de um contrato de desenvolvimento urbano entre o governo federal do Canad??, o governo da prov??ncia de Columbia Brit??nica e o governo municipal de Vancouver. Esse acordo multigovernamental, com a participa????o da comunidade, concentrou-se no aperfei??oamento dos servi??os e na introdu????o de melhorias na regi??o central-leste (Downtown Eastside) da cidade de Vancouver, ??rea afetada por profundos problemas sociais. Foi assinado em mar??o de 2000, com prazo de vig??ncia de cinco anos, e renovado em abril de 2005 por mais cinco anos. Soube aproveitar as oportunidades abertas com a candidatura de Vancouver ?? sede dos Jogos Ol??mpicos e Paraol??mpicos de Inverno de 2010, como elemento catalisador da revitaliza????o da ??rea e da constru????o de um programa que garantisse sustentabilidade social ?? regi??o. O estudo de caso analisa o processo de cria????o do acordo e as opera????es realizadas durante sua vig??ncia. Prov?? refer??ncias contextuais para o estudo de quest??es de pol??ticas p??blicas e de gest??o p??blica que envolvam coopera????o intergovernamental, gest??o de acordos complexos, governan??a de empreendimento com colabora????o de v??rios parceiros, negocia????o, pol??tica social, participa????o comunit??ria e uso de janelas de oportunidade

Estabelecendo prioridades: o or??amento da pol??cia metropolitana

O caso oferece aos alunos uma simula????o em que eles assumem a posi????o de um integrante de um conselho de pol??cia canadense, tendo como responsabilidade aprovar o or??amento da Pol??cia Metropolitana para o pr??ximo ano. Para isso, devem analisar uma lista de projetos apresentados pelo chefe de pol??cia, tomando como refer??ncia as necessidades da pol??cia para aprimoramento de seus servi??os, assim como a necessidade de conten????o fiscal. A simula????o inclui a formula????o de perguntas que esclare??am o alcance de cada projeto e a possibilidade de postergar algumas a????es propostas. O caso presta-se ao ensino de temas como processo decis??rio, or??amento e planejamento estrat??gico

Sistema radar comercial

O Sistema Radar Comercial ?? uma ferramenta in??dita de intelig??ncia comercial, que permite a identifica????o de oportunidades comerciais no mercado externo, em n??vel de seis d??gitos do Sistema Harmonizado (SH6). As informa????es e an??lises oferecidas pelo Sistema cont??m elementos b??sicos para a formula????o de estrat??gias de promo????o comercial, tanto do governo como da iniciativa privada, para o direcionamento dos fluxos de investimentos voltados para a amplia????o das exporta????es brasileiras e para o balizamento dos interesses do Brasil em negocia????es internacionais. A partir de um c??digo SH, ou de uma palavra chave que identifique determinado produto, o usu??rio do Sistema pode acessar, via internet, uma gama de an??lises sobre o produto desejado, em diferentes mercados. Al??m disso, o sistema possibilita a sele????o dos ???produtos priorit??rios???, para o Brasil ou para cada Estado da Federa????o

Preg??o: uma nova modalidade de licita????o

Inseridos no contexto de log??stica globalizada e economia digital e, objetivando minimizar os efeitos burocratizantes das modalidades em uso, o Minist??rio do Planejamento, Or??amento e Gest??o, por interm??dio da Secretaria de Log??stica e Tecnologia da Informa????o/SLTI e, do seu Departamento de Log??stica e Servi??os Gerais/DLSG, gestor das compras e contrata????es do Governo Federal, respons??vel pela formula????o de diretrizes e pol??ticas p??blicas neste segmento, idealizou e direcionou esfor??os para a cria????o de uma nova modalidade de licita????o, que atendesse aos anseios mais emergentes do governo, dos fornecedores e da sociedade em geral. Assim, em 4 de maio de 2000, instituiu-se no ??mbito da Uni??o, nos termos do art. 37 da Constitui????o Federal, a modalidade de licita????o denominada ???Preg??o???, realizada inicialmente de forma presencial, direcionada ??s aquisi????es de bens e servi??os comuns