BRST: da quebra suave à quebra espontânea da simetria

Nesta tese falamos essencialmente sobre a simetria BRST no modelo de Gribov-Zwanziger. Estudamos a quebra suave, a quebra linear e a quebra espontânea, todas da simetria BRST. Na formulação padrão do modelo, quebrada suavemente, construímos o modelo de réplica usado para estimar os valores das massas das glueballs. Utilizando campos auxiliares construímos um modelo quebrado linearmente, e utilizando basicamente o mesmo procedimento, uma formulação mais recente onde a simetria é quebrada espontâneamente.

Artificial insemination in penaeid shrimps

Artificial Insemination (AI) is a tool for genetic manipulation in the shrimp stocks. It is seen as one of the means for propagating shrimp culture to new areas by controlled reproduction. Attempts at artificial insemination in the dominant closed-thelycum penaeid shrimps species of the area viz. Metapenaeus affinis and Metapenaeus brevicornis were induced in wild adult stocks collected off Mumbai coast. Female specimens were subjected to unilateral eyestalk ablation by pinching so as to induce moulting and maturation. AI was performed two days after moulting on these females when the cuticle was still soft and flexible. Moulting also ensured rejection of initial spermatophores, if present. Response of males to electrical stimulation for spermatophore expulsion was spontaneous. Use of tissue glue for spermatophore retention was found to be unnecessary. Latency period ranged between10-16 days, while spawning occurred within 10-12 days of spermatophore transfer. Three partial spawning were recorded viz., two in Metapenaeus affinis and one in Metapenaeus brevicornis with an average spawning and hatching rates of 30% and 72.3% respectively. Average survival from first nauplius (N1) to one-day old post-larva (PLI) was a meager 3.43%. Use of AI in genetic manipulation of shrimp stocks for aquacultural purposes is indicated.

Synthesis and properties of a new series of low-molar-mass organo-siloxane derivatives

Two series of ferroelectric liquid crystalline organo-siloxanes containing a laterally attached halogen on the phenyl ring have been synthesised and characterised to determine the impact of the siloxane group and the halogen on the mesomorphism and electro-optic switching properties. Both monomesogenic and bimesogenic compounds have been studied. The monomesogenic derivatives were found to be ferroelectric with high tilt and Ps. The tilt angle of 45° and the Ps of 95nC/cm2 are almost temperature independent. The bimesogenic bromo substituted derivatives showed mainly ferroelectric phases about 60°C wide. Maximum values for the spontaneous polarisation and the tilt angle were only slightly influenced by the length of the siloxane spacer. Altering the halogen to a fluorine shifted the liquid cystalline phase slightly to higher temperatures whilst maintaining the mesophase range of 60°C.

Low short term timing jitter in an integrated monolithic extended cavity semiconductor mode-locked laser

Jitter measurements were performed on a monolithically integrated active/passive cavity multiple quantum well laser, actively mode-locked at 10 GHz via modulation of an absorber section. Sub-10 ps pulses were produced upon optimization of the drive conditions to the gain, distributed Bragg reflector, and absorber sections. A model was also developed using travelling wave rate equations. Simulation results suggest that spontaneous emission is the dominant cause of jitter, with carrier dynamics having a time constant of the order of 1 ns.

Analysis of the mechanisms for impaired high-temperature, high-speed performance of 1.3 μm InGaAsP lasers

In this paper, the static and dynamic performance of multi quantum-well (MQW) 1.3 μm InGaAsP Fabry Perot lasers is assessed experimentally and theoretically to identify the mechanisms responsible for impaired high speed performance at elevated temperature. Initially, threshold currents and spontaneous emission spectra are characterized for a range of temperatures from room temperature to 85 °C to indicate a significant increase in non-radiative current contributions. Preliminary estimates are made for the contributions of leakage and Auger recombination rates, found from the dependence of integrated spontaneous emission with carrier density. Drift-diffusion modelling is found to accurately predict the trend of threshold currents over temperature. Using gain modelling good agreement is found between the measured and predicted integrated spontaneous emission intensity. Gain measurements at 85 °C indicate a reduction in RIN frequency to 63% of the 25 °C value which matches well with experimental small signal performance.

New chiral E- and Z-isomers of the 1R,4R-2-arylidene-p-menthane-3-ones in induced cholesteric and ferroelectric liquid crystals

A novel pair of the E- and Z-isomeric 1R,4R-2-(4-heptyloxyphenyl)-benzylidene-p-menthan-3-ones has been prepared and the influence of distinctions in their molecular geometry on macroscopic properties of liquid crystal systems with the induced supra-molecular helical structure has been studied. The significantly lower helical twisting power of the chiral Z-isomer in comparison with that of E- one has been confirmed in the case of induced cholesteric systems based on 4-pentyl-4-cyanobiphenyl. The phase behavior and ferroelectric characteristics have been investigated for smectic-C* compositions based on the eutectic mixture of the homological 4-hexyloxyphenyl-4'-hexyloxy- and 4-hexyloxyphenyl-4'-octyloxybenzoates containing the novel isomeric chiral dopants. The spontaneous polarisation of the opposite signs induced by the isomeric chiral components has been revealed for the compositions studied. Distinctions in phase states, absolute values of the spontaneous polarization, smectic tilt angle and rotation viscosity of the systems obtained are discussed.

Ferroelectric liquid crystal mixtures containing chiral ether and ester compounds with the 2-arylidene-p-menthan-3-one skeleton

Some 1R,4R-2-(4-phenylbenzylidene)-p-menthane-3-one derivatives containing the ether or ester linking group between benzene rings of the arylidene fragment have been studied as chiral dopants in ferroelectric liquid crystal systems based on the eutectic mixture (1:1) of two phenylbenzoate derivatives CmH2m+1OC6H4COOC6 H4OCnH2n+1 (n = 6; m = 8, 10). The ferroelectric properties of these compositions (spontaneous polarization, rotation viscosity, smectic tilt angle as well as quantitative characteristics of their concentration dependences) were compared with those for systems including chiral dopants containing no linking group. Ferroelectric parameters of the induced ferroelectric compositions studied have been shown to depend essentially on the presence of the linking group between benzene rings and its nature as well as on the number of the benzene rings in the rigid molecular core of the chiral dopants used. For all ferroelectric liquid crystal systems studied, the influence of the chiral dopants on the thermal stability of N*, SmA and SmC* mesophases has been quantified. The influence of the linking group nature in the dopant molecules on the characteristics of the systems studied is discussed taking into account results of the conformational analysis carried out by the semi-empirical AM1 and PM3 methods.

Three-dimensional direct numerical simulations of autoignition in turbulent non-premixed flows with simple and complex chemistry

3D Direct Numerical Simulations (DNS) of autoignition in turbulent non-premixed flows between fuel and hotter air have been carried out using both 1-step and complex chemistry consisting of a 22 species n-heptane mechanism to investigate spontaneous ignition timing and location. The simple chemistry results showed that the previous findings from 2D DNS that ignition occurred at the most reactive mixture fraction (ξMR) and at small values of the conditional scalar dissipation rate (N|ξMR) are valid also for 3D turbulent mixing fields. Performing the same simulation many times with different realizations of the initial velocity field resulted in a very narrow statistical distribution of ignition delay time, consistent with a previous conjecture that the first appearance of ignition is correlated with the low-N content of the conditional probability density function of N. The simulations with complex chemistry for conditions outside the Negative Temperature Coefficient (NTC) regime show behaviour similar to the single-step chemistry simulations. However, in the NTC regime, the most reactive mixture fraction is very rich and ignition seems to occur at high values of scalar dissipation. Copyright © 2006 by ASME.

Metal Retention Experiments for the Design of Soil-Mix Technology Permeable Reactive Barriers

Soil-mix technology is effective for the construction of permeable reactive barriers (PRBs) for in situ groundwater treatment. The objective of this study was to perform initial experiments for the design of soil-mix technology PRBs according to (i) sorption isotherm, (ii) reaction kinetics and (iii) mass balance of the contaminants. The four tested reactive systems were: (i) a granular zeolite (clinoptilolite-GZ), (ii) a granular organoclay (GO), (iii) a 1:1-mixture GZ and model sandy clayey soil and (iv) a 1:1:1-mixture of GZ, GO and model soil. The laboratory experiments consisted of batch tests (volume 900mL and sorbent mass 18g) with a multimetal solution of Pb, Cu, Zn, Cd and Ni. For the adsorption experiment, the initial concentrations ranged from 0.01 to 0.5mM (2.5 to 30mg/L). The maximum metal retention was measured in a batch test (300mg/L for each metal, volume 900mL, sorbent mass 90-4.5g). The reactive material efficiency order was found to be GZ>GZ-soil mix>GZ-soil-GO mix>GO. Langmuir isotherms modelled the adsorption, even in presence of a mixed cations solution. Adsorption was energetically favourable and spontaneous in all cases. Metals were removed according to the second order reaction kinetics; GZ and the 1:1-mix were very similar. The maximum retention capacity was 0.1-0.2mmol/g for Pb in the presence of clinoptilolite; for Cu, Zn, Cd and Ni, it was below 0.05mmol/g for the four reactive systems. Mixing granular zeolite, organoclay and model soil increased the chemisorption. Providing that GZ is reactive enough for the specific conditions, GZ can be mixed to obtain the required sorption. Granular clinoptilolite addition to soil is recommended for PRBs for metal contaminated groundwater. The laboratory experiments consisted of batch tests with a multimetal solution of Pb, Cu, Zn, Cd and Ni. The four reactive materials chosen were granular zeolite, clinoptilolite and model sandy clayey soil, granular organoclay and a mix of clinoptilolite, model soil and organoclay. The reactive material efficiency order was found to be granular clinoptilolite>clinoptilolite-soil mix>clinoptilolite-soil-organoclay mix>granular organoclay. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Methylation and gene mutation in eukaryotic DNA

5-methylcytosine (m(5)C) as a rare base exists in eukaryotic genomes, which is a normal constitution in many eukaryotic DNA and the existence of m(5)C is a feature of eukaryotic DNA. Under regular physiological conditions, cytosine of eukaryotic DNA is usually methylated. Up to the present, many people consider that the m(5)C may be mutation hotspots by the deamination leading to gene mutation. Our study indicated that the spontaneous mutation caused by the transition of G.C --> A.T, in eukaryotic DNA, may result from the tautomer changing of base pairs and may also be cause by other factor actions, however it could not be caused by the deamination of m(5)C.

Altering the ordering and disordering of a triangular nanographene at room temperature.

Molecular self-organization has the potential to serve as an efficient and versatile tool for the spontaneous creation of low-dimensional nanostructures on surfaces. We demonstrate how the subtle balance between intermolecular interactions and molecule-surface interactions can be altered by modifying the environment or through manipulation by means of the tip in a scanning tunnelling microscope (STM) at room temperature. We show how this leads to the distinctive ordering and disordering of a triangular nanographene molecule, the trizigzag-hexa-peri-hexabenzocoronenes-phenyl-6 (trizigzagHBC-Ph6), on two different surfaces: graphite and Au(111). The assembly of submonolayer films on graphite reveals a sixfold packing symmetry under UHV conditions, whereas at the graphite-phenyloctane interface, they reorganize into a fourfold packing symmetry, mediated by the solvent molecules. On Au(111) under UHV conditions in the multilayer films we investigated, although disorder prevails with the molecules being randomly distributed, their packing behaviour can be altered by the scanning motion of the tip. The asymmetric diode-like current-voltage characteristics of the molecules are retained when deposited on both substrates. This paper highlights the importance of the surrounding medium and any external stimulus in influencing the molecular organization process, and offers a unique approach for controlling the assembly of molecules at a desired location on a substrate.

淋巴细胞免疫治疗原发性习惯性流产

对49例确诊为原发性习惯性流产(41.76%)中的29例采用丈夫肘静脉血40ml分离淋巴细胞行主动免疫治疗(一般妊娠前治疗两次,妊娠后治疗两次),现有17例妊娠,其中11例已分娩;5例在中期妊娠;1例失败。妊娠成功率为94.12%(16/17)。另20例未经主动免疫治疗作为对照组,妊娠成功率为27.78%(5/18),两组相比差异有显著性(P<0.05),对部分病例进行了治疗前免疫状态检测,包括微淋巴细胞毒抗体阴性,杀伤淋巴细胞低下改变的检测。结果提示丈夫淋巴细胞主动免疫法的有效性及可提高患者免疫反应性,有较可靠的临床效果及应用价值。

Effects of gamma-aminobutyric acid, progesterone and ionophore A23187 on acrosome reaction of tree shrew sperm in vitro: examination of acrosome reaction with an improved fluorescence microscopy

A number of acrosome reaction (AR) initiators have been found to be effective in inducing AR of human, laboratory and domestic animal sperm. Using an improved simple fluorescence microscopy, effects of gamma-aminobutyric acid (GABA), progesterone and ionophore A23187 on sperm AR of tree shrew, a useful animal model in biomedical research, have been investigated. Spontaneous AR in 4.92-7.53% of viable sperm was observed. Complete AR in 10.31-18.25% of viable tree shrew sperm was obviously induced by 5 mu M and 10 mu M calcium ionophore A23187, 1 mM GABA, and 5 mu M progesterone, and there were no significant differences between their abilities to initiate complete AR. No significant differences of AR percentages between 1- and 2-h treatments with A23187, progesterone and/or GABA were observed. These results suggested that the responses of tree shrew sperm to these AR initiators are similar to that of human and other mammalian sperm. (C) 1997 Elsevier Science B.V.

Active glass-polymer superlattice structure for photonic integration.

We propose an all-laser processing approach allowing controlled growth of organic-inorganic superlattice structures of rare-earth ion doped tellurium-oxide-based glass and optically transparent polydimethyl siloxane (PDMS) polymer; the purpose of which is to illustrate the structural and thermal compatibility of chemically dissimilar materials at the nanometer scale. Superlattice films with interlayer thicknesses as low as 2 nm were grown using pulsed laser deposition (PLD) at low temperatures (100 °C). Planar waveguides were successfully patterned by femtosecond-laser micro-machining for light propagation and efficient Er(3+)-ion amplified spontaneous emission (ASE). The proposed approach to achieve polymer-glass integration will allow the fabrication of efficient and durable polymer optical amplifiers and lossless photonic devices. The all-laser processing approach, discussed further in this paper, permits the growth of films of a multitude of chemically complex and dissimilar materials for a range of optical, thermal, mechanical and biological functions, which otherwise are impossible to integrate via conventional materials processing techniques.

Cortical thickness mapping to identify focal osteoporosis in patients with hip fracture.

BACKGROUND: Individuals with osteoporosis are predisposed to hip fracture during trips, stumbles or falls, but half of all hip fractures occur in those without generalised osteoporosis. By analysing ordinary clinical CT scans using a novel cortical thickness mapping technique, we discovered patches of markedly thinner bone at fracture-prone regions in the femurs of women with acute hip fracture compared with controls. METHODS: We analysed CT scans from 75 female volunteers with acute fracture and 75 age- and sex-matched controls. We classified the fracture location as femoral neck or trochanteric before creating bone thickness maps of the outer 'cortical' shell of the intact contra-lateral hip. After registration of each bone to an average femur shape and statistical parametric mapping, we were able to visualise and quantify statistically significant foci of thinner cortical bone associated with each fracture type, assuming good symmetry of bone structure between the intact and fractured hip. The technique allowed us to pinpoint systematic differences and display the results on a 3D average femur shape model. FINDINGS: The cortex was generally thinner in femoral neck fracture cases than controls. More striking were several discrete patches of statistically significant thinner bone of up to 30%, which coincided with common sites of fracture initiation (femoral neck or trochanteric). INTERPRETATION: Femoral neck fracture patients had a thumbnail-sized patch of focal osteoporosis at the upper head-neck junction. This region coincided with a weak part of the femur, prone to both spontaneous 'tensile' fractures of the femoral neck, and as a site of crack initiation when falling sideways. Current hip fracture prevention strategies are based on case finding: they involve clinical risk factor estimation to determine the need for single-plane bone density measurement within a standard region of interest (ROI) of the femoral neck. The precise sites of focal osteoporosis that we have identified are overlooked by current 2D bone densitometry methods.