Performance comparison of duobinary modulation formats for 40 Gb/s long-haul WDM transmissions

With their compact spectrum and high tolerance to residual chromatic dispersion, duobinary formats are attractive for the deployment of 40 Gb/s technology on 10 Gb/s WDM Long-Haul transmission infrastructures. Here, we compare the robustness of various duobinary formats when facing 40 Gb/s transmission impairments.

Robustness of the OOK modulation formats at 40 Gbit/s in the practical system infrastructure

We experimentally investigate the robustness of OOK modulation formats at 40 Gbit/s versus transmission impairments and optical filtering. This study is a pre-requisite for the implementation of robust transparent networks.

High spectral efficiency transmission emulation for non-linear transmission performance estimation for high order modulation formats

We demonstrate a simple method to experimentally evaluate nonlinear transmission performance of high order modulation formats using a low number of channels and channel-like ASE. We verify it's behaviour is consistent with the AWGN model of transmission.

Robustness of 40 Gb/s ASK modulation formats in the practical system infrastructure

In this work, we analyzed by means of numerical and laboratory experiments the resilience of 40 Gb/s amplitude shift keying modulation formats to transmission impairments in standard single-mode fiber lines as well as to optical filtering introduced by the optical add/drop multiplexer cascade. Our study is a pre-requisite to assess the implementation of cost-effective 40 Gb/s modulation technology in next generation high bit-rate robust optical transport networks. © 2006 Optical Society of America.

Performance comparison of 40 Gb/s ULH transmissions using CSRZ-ASK or CSRZ-DPSK modulation formats on Ultra Wave™ fiber

In this work we present extensive comparisons between numerical modelling and experimental measurements of the transmission performance of either CSRZ-ASK or CSRZ-DPSK modulation formats for 40-Gb/s WDM ULH systems on UltraWave™ fiber spans with all-Raman amplification. We numerically optimised the amplification and the signal format parameters for both CSRZ-DPSK and CSRZ-ASK formats. Numerical and experimental results show that, in a properly optimized transmission link, the DPSK format permits to double the transmission distance (for a given BER level) with respect to the ASK format, while keeping a substantial OSNR margin (on ASK modulation) after the propagation in the fiber line. Our comparison between numerical and experimental results permits to identify what is the most suitable BER estimator in assessing the transmission performance when using the DPSK format. © 2007 Optical Society of America.

An Evaluation of Three Nutrition Labeling Formats for Restaurant Menus

This study evaluated three menu nutrition labeling formats: calorie only information, a healthy symbol, and a nutrient list. Daily sales data for a table-service restaurant located on a university campus were recorded during a four-week period from January to February 2013 to examine changes in average nutritional content of the entrees purchased by customers when different nutrition labels were provided. A survey was conducted to assess the customers’ use of nutrition labels, their preferences among the three labeling formats, their entree selections, their cognitive beliefs with regard to healthy eating, and their demographic characteristics. A total of 173 questionnaires were returned and included in data analysis. Analysis of Variance (ANOVA) and regression analyses were performed using SAS. The results showed that favorable attitudes toward healthy eating and the use of nutrition labels were both significantly associated with healthier entrée selections. Age and diet status had some effects on the respondent’s use of nutrition labels. The calorie only information format was the most effective in reducing calories contained in the entrees sold, and the nutrient list was most effective in reducing fat and saturated fat content of the entrees sold. The healthy symbol was the least effective format, but interestingly enough, was most preferred by respondents. The findings provide support for future research and offer implications for policy makers, public health professionals, and foodservice operations.

Development of a dissolvable microneedle influenza vaccine patch

Delivery of large molecular weight biological molecules to the epidermis and dermis is constrained by the tough outer layer of the epidermis, the stratum corneum (sc). Microneedle technologies attempt to overcome this physical barrier using sharp micron-size projections to penetrate the sc. Dissolvable microneedles (DMN), are a particular microneedle design whereby the needle structure is composed of a soluble matrix that upon application to the skin, dissolves releasing the vaccine load into skin. This thesis examines (1) the formulation and processing considerations around DMN fabrication, (2) the immunogenicity of DMN containing trivalent influenza vaccine (TIV) in pre-clinical mouse and pig models and (3) the thermostability of these DMN formulations during storage. The results demonstrate the importance of formulation for microneedle formation and mechanical strength. Trehalose and polyvinylalcohol based formulations produced optimal microneedle structures and were amenable to piezoelectric dispensing; allowing for precise multi-layered DMN to be fabricated. The effect of drying conditions was assessed and found to be critical for DMN mechanical strength and skin penetration. The antibody responses to TIV generated by DMN-mediated vaccination were comparable or greater to those induced by immunization with a commercial TIV via the IM route in mice. DMN mediated immunisation resulted in a significantly broader humoral response to heterotypic influenza viruses compared to IM delivery. Stored at 40°C, a licensed seasonal influenza vaccine incorporated into DMN array was thermostable for at least 6 month as determined by Single Radial Immunodiffusion and immunogenicity in mice. The thesis advances the field of DMN influenza vaccination by elucidating important processing and formulation considerations in the fabrication of highly reproducible DMN. It also demonstrated that DMN can induce broader, larger humoral responses than conventional IM administration while demonstrating enhanced accelerated stability. Crucially, this works advances an automated fabrication system that will allow for clinical translation of DMN.

Non-conventional advertising formats in television versus spots: An analysis based on the generated recall

Advertising investment and audience figures indicate that television continues to lead as a mass advertising medium. However, its effectiveness is questioned due to problems such as zapping, saturation and audience fragmentation. This has favoured the development of non-conventional advertising formats. This study provides empirical evidence for the theoretical development. This investigation analyzes the recall generated by four non-conventional advertising formats in a real environment: short programme (branded content), television sponsorship, internal and external telepromotion versus the more conventional spot. The methodology employed has integrated secondary data with primary data from computer assisted telephone interviewing (CATI) were performed ad-hoc on a sample of 2000 individuals, aged 16 to 65, representative of the total television audience. Our findings show that non-conventional advertising formats are more effective at a cognitive level, as they generate higher levels of both unaided and aided recall, in all analyzed formats when compared to the spot.

Toward A Reliable Quality Control Test For Microneedle Insertion

Microneedles (MNs) are emerging devices that can be used for the delivery of drugs at specific locations1. Their performance is primarily judged by different features and the penetration through tissue is one of the most important aspects to evaluate. For detailed studies of MN performance different kind of in-vitro, exvivo and in-vivo tests should be performed. The main limitation of some of these tests is that biological tissue is too heterogeneous, unstable and difficult to obtain. In addition the use of biological materials sometimes present legal issues. There are many studies dealing with artificial membranes for drug diffusion2, but studies of artificial membranes for Microneedle mechanical characterization are scarce3. In order to overcome these limitations we have developed tests using synthetic polymeric membranes instead of biological tissue. The selected artificial membrane is homogeneous, stable, and readily available. This material is mainly composed of a roughly equal blend of a hydrocarbon wax and a polyolefin and it is commercially available under the brand name Parafilm®. The insertion of different kind of MN arrays prepared from crosslinked polymers were performed using this membrane and correlated with the insertion of the MN arrays in ex-vivo neonatal porcine skin. The insertion depth of the MNs was evaluated using Optical coherence tomography (OCT). The implementation of MN transdermal patches in the market can be improved by make this product user-friendly and easy to use. Therefore, manual insertion is preferred to other kind of procedures. Consequently, the insertion studies were performed in neonatal porcine skin and the artificial membrane using a manual insertion force applied by human volunteers. The insertion studies using manual forces correlated very well with the same studies performed with a Texture Analyzer equipment. These synthetic membranes seem to mimic closely the mechanical properties of the skin for the insertion of MNs using different methods of insertion. In conclusion, this artificial membrane substrate offers a valid alternative to biological tissue for the testing of MN insertion and can be a good candidate for developing a reliable quality control MN insertion test.

Microwave-Assisted Process For The Preparation of Microneedle Arrays.

A microwave (MW)-assisted crosslinking process to prepare hydrogel-forming microneedle (MN) arrays was evaluated. The effects of the crosslinking process on the MN arrays characteristics was evaluated. The results suggest that MN arrays prepared using the MW assisted process had equivalent properties to those prepared conventionally, but can be produced 30 times faster.

Stimuli-Responsive Microneedle Arrays For On-Demand Drug Delivery

Pulsatile, or “on-demand”, delivery systems have the capability to deliver a therapeutic molecule at the right time/site of action and in the right amount (1). Pulsatile delivery systems present multiple benefits over conventional dosage forms and provide higher patient compliance. The combination of stimuli-responsive materials with the drug delivery capabilities of hydrogel-forming MN arrays (2) opens an interesting area of research. In the present work we describe, a stimuli-responsive hydrogel-forming microneedle (MN) array that enable delivery of a clinically-relevant model drug (ibuprofen) upon application of UV radiation (Figure 1A). MN arrays were prepared using a micromolding technique using a polymer prepared from 2-hydroxyethyl methacrylate (HEMA) and ethylene glycol dimethacrylate (EGDMA) (Figure 1B). The arrays were loaded with up to 5% (w/w) ibuprofen included in a light-responsible conjugate (3,5-dimethoxybenzoin conjugate) (2). The presence of the conjugate inside the MN arrays was confirmed by Raman spectroscopy measurements. MN arrays were tested in vitro showing that they were able to deliver up to three doses of 50 mg of ibuprofen after application of an optical trigger (wavelength of 365 nm) over a long period of time (up to 160 hours) (Figure 1C and 1D). The work presented here is a probe of concept and a modified version of the system should be used as UV radiation is shown to be the major etiologic agent in the development of skin cancers. Consequently, for future applications of this technology an alternative design should be developed. Based on the previous research dealing with hydrogel forming MN arrays a suitable strategy will be to use hydrogel-forming MN arrays containing a backing layer made with the material described in this work as the drug reservoir (2). Finally, a porous layer of a material that blocks UV radiation should be included between the MN array and the drug reservoir. Therefore radiation can be applied to the system without reaching the skin surface. Therefore after modification, the system described here interesting properties as “on-demand” release system for prolonged periods of time. This technology has potential for use in “on-demand” delivery of a wide range of drugs in a variety of applications relevant to enhanced patient care.

Alternative drying techniques for the manufacturing of hydrogel-forming and dissolving microneedle arrays.

Dissolving polymeric microneedle arrays and hydrogel-forming microneedle arrays have attracted much attention during recent years due mainly to their biocompatibility and capacity for enhanced drug delivery. Nevertheless, for the production of this type of devices, typically, a drying step is required. Microneedles are prepared following a micromoulding technique using aqueous blends of Gantrez® S-97. Currently, production of microneedles arrays involves a long drying process of 48 hours. Therefore alternative drying methods were investigated including microwave radiation and hot air convection.

The Use of a Pressure-Indicating Sensor Film to Provide Feedback upon Hydrogel-Forming Microneedle Array Self-Application In Vivo

PURPOSE:
To evaluate the combination of a pressure-indicating sensor film with hydrogel-forming microneedle arrays, as a method of feedback to confirm MN insertion in vivo.
METHODS:
Pilot in vitro insertion studies were conducted using a Texture Analyser to insert MN arrays, coupled with a pressure-indicating sensor film, at varying forces into excised neonatal porcine skin. In vivo studies involved twenty human volunteers, who self-applied two hydrogel-forming MN arrays, one with a pressure-indicating sensor film incorporated and one without. Optical coherence tomography was employed to measure the resulting penetration depth and colorimetric analysis to investigate the associated colour change of the pressure-indicating sensor film.
RESULTS:
Microneedle insertion was achieved in vitro at three different forces, demonstrating the colour change of the pressure-indicating sensor film upon application of increasing pressure. When self-applied in vivo, there was no significant difference in the microneedle penetration depth resulting from each type of array, with a mean depth of 237 μm recorded. When the pressure-indicating sensor film was present, a colour change occurred upon each application, providing evidence of insertion.
CONCLUSIONS:
For the first time, this study shows how the incorporation of a simple, low-cost pressure-indicating sensor film can indicate microneedle insertion in vitro and in vivo, providing visual feedback to assure the user of correct application. Such a strategy may enhance usability of a microneedle device and, hence, assist in the future translation of the technology to widespread clinical use.

Wavelength converters based on four-wave mixing in semiconductor optical amplifiers for advanced modulation formats

Les convertisseurs de longueur d’onde sont essentiels pour la réalisation de réseaux de communications optiques à routage en longueur d’onde. Dans la littérature, les convertisseurs de longueur d’onde basés sur le mélange à quatre ondes dans les amplificateurs optiques à semi-conducteur constituent une solution extrêmement intéressante, et ce, en raison de leurs nombreuses caractéristiques nécessaires à l’implémentation de tels réseaux de communications. Avec l’émergence des systèmes commerciaux de détection cohérente, ainsi qu’avec les récentes avancées dans le domaine du traitement de signal numérique, il est impératif d’évaluer la performance des convertisseurs de longueur d’onde, et ce, dans le contexte des formats de modulation avancés. Les objectifs de cette thèse sont : 1) d’étudier la faisabilité des convertisseurs de longueur d’onde basés sur le mélange à quatre ondes dans les amplificateurs optiques à semi-conducteur pour les formats de modulation avancés et 2) de proposer une technique basée sur le traitement de signal numérique afin d’améliorer leur performance. En premier lieu, une étude expérimentale de la conversion de longueur d’onde de formats de modulation d’amplitude en quadrature (quadrature amplitude modulation - QAM) est réalisée. En particulier, la conversion de longueur d’onde de signaux 16-QAM à 16 Gbaud et 64-QAM à 5 Gbaud dans un amplificateur optique à semi-conducteur commercial est réalisée sur toute la bande C. Les résultats démontrent qu’en raison des distorsions non-linéaires induites sur le signal converti, le point d’opération optimal du convertisseur de longueur d’onde est différent de celui obtenu lors de la conversion de longueur d’onde de formats de modulation en intensité. En effet, dans le contexte des formats de modulation avancés, c’est le compromis entre la puissance du signal converti et les non-linéarités induites qui détermine le point d’opération optimal du convertisseur de longueur d’onde. Les récepteurs cohérents permettent l’utilisation de techniques de traitement de signal numérique afin de compenser la détérioration du signal transmis suite à sa détection. Afin de mettre à profit les nouvelles possibilités offertes par le traitement de signal numérique, une technique numérique de post-compensation des distorsions induites sur le signal converti, basée sur une analyse petit-signal des équations gouvernant la dynamique du gain à l’intérieur des amplificateurs optiques à semi-conducteur, est développée. L’efficacité de cette technique est démontrée à l’aide de simulations numériques et de mesures expérimentales de conversion de longueur d’onde de signaux 16-QAM à 10 Gbaud et 64-QAM à 5 Gbaud. Cette méthode permet d’améliorer de façon significative les performances du convertisseur de longueur d’onde, et ce, principalement pour les formats de modulation avancés d’ordre supérieur tel que 64-QAM. Finalement, une étude expérimentale exhaustive de la technique de post-compensation des distorsions induites sur le signal converti est effectuée pour des signaux 64-QAM. Les résultats démontrent que, même en présence d’un signal à bruité à l’entrée du convertisseur de longueur d’onde, la technique proposée améliore toujours la qualité du signal reçu. De plus, une étude du point d’opération optimal du convertisseur de longueur d’onde est effectuée et démontre que celui-ci varie en fonction des pertes optiques suivant la conversion de longueur d’onde. Dans un réseau de communication optique à routage en longueur d’onde, le signal est susceptible de passer par plusieurs étages de conversion de longueur d’onde. Pour cette raison, l’efficacité de la technique de post-compensation est démontrée, et ce pour la première fois dans la littérature, pour deux étages successifs de conversion de longueur d’onde de signaux 64-QAM à 5 Gbaud. Les résultats de cette thèse montrent que les convertisseurs de longueur d’ondes basés sur le mélange à quatre ondes dans les amplificateurs optiques à semi-conducteur, utilisés en conjonction avec des techniques de traitement de signal numérique, constituent une technologie extrêmement prometteuse pour les réseaux de communications optiques modernes à routage en longueur d’onde.

Techniques en appui des formats de modulation avancés pour les futurs réseaux optiques

Les systèmes de communication optique avec des formats de modulation avancés sont actuellement l’un des sujets de recherche les plus importants dans le domaine de communication optique. Cette recherche est stimulée par les exigences pour des débits de transmission de donnée plus élevés. Dans cette thèse, on examinera les techniques efficaces pour la modulation avancée avec une détection cohérente, et multiplexage par répartition en fréquence orthogonale (OFDM) et multiples tonalités discrètes (DMT) pour la détection directe et la détection cohérente afin d’améliorer la performance de réseaux optiques. Dans la première partie, nous examinons la rétropropagation avec filtre numérique (DFBP) comme une simple technique d’atténuation de nonlinéarité d’amplificateur optique semiconducteur (SOA) dans le système de détection cohérente. Pour la première fois, nous démontrons expérimentalement l’efficacité de DFBP pour compenser les nonlinéarités générées par SOA dans un système de détection cohérente porteur unique 16-QAM. Nous comparons la performance de DFBP avec la méthode de Runge-Kutta quatrième ordre. Nous examinons la sensibilité de performance de DFBP par rapport à ses paramètres. Par la suite, nous proposons une nouvelle méthode d’estimation de paramètre pour DFBP. Finalement, nous démontrons la transmission de signaux de 16-QAM aux taux de 22 Gbaud sur 80km de fibre optique avec la technique d’estimation de paramètre proposée pour DFBP. Dans la deuxième partie, nous nous concentrons sur les techniques afin d’améliorer la performance des systèmes OFDM optiques en examinent OFDM optiques cohérente (CO-OFDM) ainsi que OFDM optiques détection directe (DDO-OFDM). Premièrement, nous proposons une combinaison de coupure et prédistorsion pour compenser les distorsions nonlinéaires d’émetteur de CO-OFDM. Nous utilisons une interpolation linéaire par morceaux (PLI) pour charactériser la nonlinéarité d’émetteur. Dans l’émetteur nous utilisons l’inverse de l’estimation de PLI pour compenser les nonlinéarités induites à l’émetteur de CO-OFDM. Deuxièmement, nous concevons des constellations irrégulières optimisées pour les systèmes DDO-OFDM courte distance en considérant deux modèles de bruit de canal. Nous démontrons expérimentalement 100Gb/s+ OFDM/DMT avec la détection directe en utilisant les constellations QAM optimisées. Dans la troisième partie, nous proposons une architecture réseaux optiques passifs (PON) avec DDO-OFDM pour la liaison descendante et CO-OFDM pour la liaison montante. Nous examinons deux scénarios pour l’allocations de fréquence et le format de modulation des signaux. Nous identifions la détérioration limitante principale du PON bidirectionnelle et offrons des solutions pour minimiser ses effets.