Dichotic listening and corpus callosum magnetic resonance imaging in relapsing-remitting multiple sclerosis with emphasis on sex differences.

Twenty-five early-onset relapsing-remitting multiple sclerosis patients (12 women and 13 men) with mild disability were compared with 25 matched controls in a dichotic listening (DL) test under nonforced and forced attentional-shift conditions. Patients showed left ear impairment and no left ear advantage in the forced-left condition. Four corpus callosum (CC) regions were measured in patients on a rnidsaggital magnetic resonance imaging scan. The right ear score was negatively correlated whereas the left ear score was positively correlated with CC regions (significant only for the nonforced condition). Moreover, in men, the correlations with DL scores were linked mainly to the splenium and posterior isthmus, and in women, they were stronger for anterior isthmus and posterior body. An inverse correlation between months of disease evolution and CC area was found only in women. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

STOLAS: switching technologies for optically labeled signals

GMPLS-based labeled optical burst switching (LOBS) networks are being considered as the next-generation optical Internet. GMPLS includes wavelength switching next to label and fiber (space) switching. We present a new concept of optically labeling bursts of packets suitable for LOBS networks supported by GMPLS. It is based on angle modulation, which enables control information to modulate the phase or frequency of the optical carrier, while payload data are transmitted via intensity modulation (IM). In particular, the optical label is orthogonally modulated, with respect to the payload, using either frequency shift keying or differential phase shift keying. We present a performance analysis of the modulation schemes by means of simulations where the influence of the payload IM extinction ratio and laser linewidth are investigated. In addition, the transmission performance of an IM/FSK combined modulated signal is experimentally validated at 10 Gb/s, demonstrating at the same time an FSK label swapping operation. Finally, a suitable optical label-controlled switch design is proposed that takes advantage of these novel labeling techniques, and efficiently combines widely tunable, fast switching lasers and SOA-MZI wavelength converters with an arrayed waveguide grating router.     

All-optical processing of time-serial IM/DPSK encoded label and payload packets

We demonstrate an all-optical label and payload processor based on nonlinear optical signal processing with semiconductor optical amplifiers. The processor separates the label and the payload, and generates a synchronization pulse, used to control the label comparison operation in an all-optical routing node.     

Light coupling characteristics of corrugated quantum-well infrared photodetectors

Corrugated quantum-well infrared photodetectors (C-QWIPs) offer simple detector architectures for large-format infrared focal plane arrays (FPAs). The detector relies on inclined sidewalls to couple normal incident light into the absorbing material. Based on a simplified geometrical-optics (GO) model, this light coupling scheme is expected to be effective with little wavelength dependence. In this work, we apply the modal transmission-line (MTL) modeling technique to study in detail its light coupling characteristics and compare the results with the GO model and experimental data. We find that the results of the GO model agree reasonably well with those of the rigorous MTL model for corrugations with metal cover, and both modeling procedures are consistent with experimental data. In particular, both models predict similar increase in the quantum efficiency /spl eta/ with the size of the corrugations, and both indicate similar limiting /spl eta/ when the corrugation becomes very large. For linear corrugations with thick substrates, the maximum /spl eta/ is about 30%. On the other hand, there are also significant differences between the two models when the effects of phase coherence are important. Since the phase of the radiation is taken into account in the MTL formalism but not in the GO formalism, the MTL model is more generally applicable and is more capable of explaining different detector characteristics. For example, it predicts a smaller /spl eta/ for air or epoxy-covered C-QWIPs because of finite optical transmission through the sharp corners in the corrugations, and it indicates an oscillatory function of /spl eta/ because of the existence of optical fringes. It also reveals the wavelength dependence of the coupling, which becomes more pronounced as the thickness of the substrate layer is reduced.     

An optical IM/FSK coding technique for the implementation of a label-controlled arrayed waveguide packet router

In this paper, we present a new concept of optical packet/burst switching suitable for generalized multiprotocol label switched (GMPLS)-based optical networks. In such networks, optical labeled switched paths are being established in a similar way as label-switched paths in MPLS. We use a wavelength label as well as an orthogonally modulated label, with respect to the payload modulation format, and which is encoded using either frequency-shift keying (FSK) or differential phase-shift keying (DPSK). Wavelength is used for switching in the node, whereas the orthogonal label defines the label-switched path. We present both simulation and experimental results to assess transmission performance of the proposed combined modulation scheme. In addition, we propose a suitable optical node architecture that can take advantage of this stacked label concept. Toward this, we use widely tunable wavelength converters to efficiently route IM/FSK (or IM/DPSK) optically labeled packets in an arrayed-waveguide grating (AWG)-based node structure. We present performance simulation results in terms of packet loss ratio and internal block probability. Internal blocking is an inherent problem of AWG optical routers, and a specific wavelength assignment algorithm has been developed to minimize it. Finally, the feasibility of IM/FSK transmission is experimentally demonstrated over an 88-km single-mode fiber span, and novel aspects of FSK generation and detection techniques are presented.     

Suppression of preneoplastic changes in the intestine of rats fed low levels of polyamines

Administration for 7 days of an enteral diet that is naturally deficient in polyamines strikingly reduces the preneoplastic changes observed in the intestines of adult Wistar rats previously treated with the carcinogen 1,2-dimethylhydrazine. On the contrary, supplementing the enteral diet with spermidine favors preneoplastic development. The effects of the low-polyamine diet included a 40% decline in the putrescine content of the intestinal mucosa, a significant decrease in the turnover rate of the epithelial cells from the crypts to villus tip in the ileum, and a 2-fold reduction in the number of abnormal colonic crypts. The experimental data support the view that it might be of interest to control the dietary intake of polyamines in the clinical management of cancer patients.     

Estimation of Circulating Blood Volume from a Tracer-Response Curve

A method is developed for analyzing sudden injection dye (tracer) curves in order to obtain the distribution of first passage times in the mammalian circulation. The moments of the distribution yield useful quantities such as circulating blood volume. The method involves the use of Liouville-Neumann series. The calculation of the first passage time distribution (FPD) also requires a deconvolution through the use of Fourier transforms, but the calculation of moments does not.     

Operations research in the high-level synthesis of integrated circuits

The acceptance of high-level synthesis tools and methodologies by the design engineers depends on their efficiency in producing circuits with small silicon areas and high operating speeds. This paper shows how this efficiency can be achieved through the use of several operations research techniques applied to the many optimization problems that must be solved. These include: shortest path algorithms, integer programming techniques applied to silicon area minimization, force directed scheduling to optimize the number of operators and cost/speed trade-offs of logical gates. This paper presents several examples providing an operations research solution to each of them.     

Angiotensin II type 1 receptor A1166C gene polymorphism and essential hypertension in San Luis.

Essential hypertension is considered a multifactorial trait resulting from a combination of environmental and genetic factors. The angiotensin II type 1 receptor mediates the vasoconstrictor and growth-promoting effects of Ang II. The A1166C polymorphism of the AT1 receptor gene may be associated with cardiovascular phenotypes, such as high arterial blood pressure, aortic stiffness, and increased cardiovascular risk. We investigated the association between this A1166C polymorphism and hypertension in hypertense and normotense subjects from San Luis (Argentina) by mismatch PCR-RFLP analysis. Hypertense patients exhibited significant increases in lipid related values and body mass index. The frequency of occurrence of the C1166 allele was higher among patients with hypertension (0.19) than in the control group (0.06). No significant association was found between this polymorphism and essential hypertension in the study population, although the AC genotype prevalence was higher in patients with hypertension and positive family history of hypertension (32%) than in control subjects (12%). Patients with the A1166C polymorphism exhibited higher levels of serum total cholesterol, LDL-cholesterol and BMI than in control subjects. Taken together the genotype and biochemical parameters and considering the restrictive selection criteria used, the present results suggest a correlation between AT1 A1166C gene polymorphism and risk of cardiovascular disease.