WDM/TDM PON bidirectional networks single-fiber/wavelength RSOA-based ONUs layer 1/2 optimization

This Thesis proposes the design and the optimization of a hybrid WDM/TDM PON at the L1 (PHY) and L2 (MAC) layers, in terms of minimum deployment cost and enhanced performance for Greenfield NGPON. The particular case of RSOA-based ONUs and ODN using a single-fibre/single-wavelength is deeply analysed. In this WDM/TDM PON relevant parameters are optimized. Special attention has been given at the main noise impairment in this type of networks: the Rayleigh Backscattering effect, which cannot be prevented. To understand its behaviour and mitigate its effects, a novel mathematical model for the Rayleigh Backscattering in burst mode transmission is presented for the first time, and it has been used to optimize the WDM/TDM RSOA based PON. Also, a cost-effective, simple design SCM WDM/TDM PON with rSOA-based ONU, was optimized and implemented. This prototype was successfully tested showing high performance, robustness, versatility and reliability. So, the system is able to give coverage up to 1280 users at 2.5 Gb/s / 1.25 Gb/s downstream/upstream, over 20 Km, and being compatible with the GPON ITU-T recommendation. This precedent has enabled the SARDANA network to extend the design, architecture and capabilities of a WDM/TDM PON for a long reach metro-access network (100 km). A proposal for an agile Transmission Convergence sub-layer is presented as another relevant contribution of this work. It is based on the optimization of the standards GPON and XG-PON (for compatibility), but applied to a long reach metro-access TDM/WDM PON rSOA-based network with higher client count. Finally, a proposal of physical implementation for the SARDANA layer 2 and possible configurations for SARDANA internetworking, with the metro network and core transport network, are presented

The upgrade of the ALICE TPC with GEMs and continuous readout

The upgrade of the ALICE TPC will allow the experiment to cope with the high interaction rates foreseen for the forthcoming Run 3 and Run 4 at the CERN LHC. In this article, we describe the design of new readout chambers and front-end electronics, which are driven by the goals of the experiment. Gas Electron Multiplier (GEM) detectors arranged in stacks containing four GEMs each, and continuous readout electronics based on the SAMPA chip, an ALICE development, are replacing the previous elements. The construction of these new elements, together with their associated quality control procedures, is explained in detail. Finally, the readout chamber and front-end electronics cards replacement, together with the commissioning of the detector prior to installation in the experimental cavern, are presented. After a nine-year period of R&D, construction, and assembly, the upgrade of the TPC was completed in 2020.publishedVersio

High-Throughput Automated Patch Clamp Investigations on Ion Channels in Erythrocytes

Trotz ihrer morphologischen Einfachheit ist die Membran der roten Blutkörperchen (Erythrozyten) mit einer Reihe von Transportern und Ionenkanälen ausgestattet, die bisher nicht vollständig charakterisiert sind und deren biologische Rolle noch wenig verstanden ist. Die meisten Techniken zur Untersuchung von Ionenkanälen messen summierte Effekte großer Zellpopulationen und verbergen so jede mutmaßliche Variabilität von Zelle zu Zelle. Die Patch-Clamp-Technik hat sich als effektives Werkzeug zur Entdeckung und Charakterisierung von Ionenkanälen auf Einzelzellenebene erwiesen. Dies besonders wichtig für Erythrozyten von Säugetieren, die eine hohe Heterogenität der Leitfähigkeit zwischen verschiedenen Spendern, und auch zwischen Zellen desselben Spenders aufweisen (Kaestner et al., 2004; Minetti et al., 2013). Die Entwicklung des automatisierten Patch-Clamps ermöglichte es, eine hohe Anzahl von Zellen gleichzeitig unter identischen experimentellen Bedingungen zu untersuchen, wodurch Zellheterogenität erstmals umfassend bestimmt wurde. In dieser Arbeit wurden Gárdos- und Piezo1-Kanäle als Hauptuntersuchungsziele ausgewählt, da sie eine prominente Rolle in erythrozytären Erkrankungen, im Einzelnen Gárdos-Kanalopathie (Fermo et al., 2017) und hereditäre Xerozytose (Zarychanski et al., 2012; Bae et al., 2013), spielen. Ziel dieser Arbeit war es, automatisierte Patch-Clamp-Assays zur Charakterisierung dieser Kanäle in Erythrozyten zu entwickeln. Es gibt bisher nur vereinzelte Publikationen zu whole-cell Patch-Clamp-Messungen von Gárdos-Kanälen in Erythrozyten (Grygorczyk et al., 1984; Wolff et al., 1988), wahrscheinlich aufgrund der geringen Expression des Proteins in zirkulierenden Erythrozyten. Der hochparallelisierte Ansatz der automatisierten Patch-Clamp-Technologie ermöglicht zuverlässig die Identifizierung von Gárdos-Strömen in Zelltypen mit einer oft geringen Anzahl von Kanälen und einer großen Heterogenität der Expression, wie bei Erythrozyten. Bisherige Piezo1-Kanaluntersuchungen zeigen, dass die Substanz Yoda1 Piezo1-Ströme bewirken kann, die empfindlich auf GdCl3 (unspezifischer Inhibitor dehnungsaktivierter Kanäle), nicht jedoch auf TRAM-34 (spezifischer Gárdos-Kanalinhibitor) reagieren. Die Anwendung dieses Assays auf Erythrozyten von Patienten mit einer neuartigen PIEZO1 R2110W-Mutation zeigte eine erhöhte Anzahl der Yoda1-empfindlichen Zellen und eine stärkere Antwort auf Yoda1 bei Patienten im Vergleich zu Kontroll-Erythrozyten. In Kombination mit der Untersuchung der Proteinstruktur, die den R2110W-Rests in einem gating-sensitiven Bereich des Kanals lokalisiert, deuten die Patch-Clamp-Ergebnisse darauf hin, dass die neue Piezo1-Mutation eine gain-of-function-Mutation ist (Rotordam et al., 2019). Zusammenfassend zeigt diese Arbeit, dass die automatisierte Patch-Clamp-Methode robuste Assays zur Untersuchung von Ionenkanälen (Gárdos und Piezo1) in Primärzellen liefert. Die Hochdurchsatztechnologie ermöglichte die Entwicklung eines zuverlässigen Assays für gering exprimierte Ionenkanäle bei hoher Heterogenität der Zellen. So war es möglich, eine neuartige Kanalmutation auf funktioneller Ebene direkt in Patientenzellen zu charakterisieren, ohne die Mutation in einem heterologen Expressionssystem exprimieren zu müssen. Dieser Ansatz kann zum Nachweis und zur Charakterisierung weiterer Kanalopathien verwendet werden, die nicht auf Erythrozyten beschränkt sind, und kann generell als zur Gensequenzierung komplementärer Routine-Screening-Assay für Krankheiten dienen, die mit Ionenkanalstörungen zusammenhängen.Despite the morphological simplicity, the Red Blood Cell (RBC) membrane is endowed with a number of transporters and ion channels, yet not fully characterized and whose biological role is still poorly understood. Most of the techniques used to investigate ion channels are addressed to large populations of cells, thus concealing any putative cell-to-cell variability. The patch clamp technique has proven to be a valid tool for the discovery and characterization of ion channels at a single-cell level. This is of particular relevance for mammalian RBCs, which present a high heterogeneity of conductance not only between different donors but also among cells of the same donor (Kaestner et al., 2004; Minetti et al., 2013). The advent of automated patch clamp allowed to probe an increased number of cells at the same time under identical experimental conditions, thus tackling cell heterogeneity issues. In this thesis, Gárdos and Piezo1 channels were selected as main targets of investigation due to their relevance in RBC-related diseases, i.e. Gárdos channelopathy (Fermo et al., 2017) and hereditary xerocytosis (Zarychanski et al., 2012; Bae et al., 2013). The aim of this work was to develop automated patch clamp assays for characterizing those channels in RBCs. As for Gárdos channels, whole cell recordings reported so far are fragmentary probably due to the low expression of the protein in circulating RBCs (Grygorczyk et al., 1984; Wolff et al., 1988). By increasing the number of cells recorded at the same time, the automated patch clamp technology allowed to identify Gárdos-mediated currents in primary cells with a low-copy number of channels and a large heterogeneity of conductance as RBCs. Piezo1 channels investigations confirmed that application of Yoda1 alone is able to elicit currents sensitive to GdCl3 (non-specific stretch-activated channels inhibitor) but not TRAM-34 (specific Gárdos channel blocker). When transferred to patients carrying a novel PIEZO1 R2110W mutation, the assay revealed that the number of responders and the magnitude of the response to Yoda1 increased in patient compared to control RBCs. This result, combined with structural studies identifying the R2110W residue in a gating sensitive area of the channel, suggested that the novel Piezo1 mutation is gain-of-function (Rotordam et al., 2019). Altogether, this work demonstrates that automated patch clamping provides robust assays to investigate ion channels (Gárdos and Piezo1) in primary cells. The high-throughput technology allowed to tackle issues as response heterogeneity and low expression of the channels, and to characterize a novel channel mutation at a functional level directly from patient cells, without having to express the mutation in a heterologous expression system. This approach may be used to detect other channelopathies not limited to RBCs and may serve as routine screening assay for diseases related to ion channel dysfunctions in general, complementary to gene sequencing

Optical Wireless Data Center Networks

Bandwidth and computation-intensive Big Data applications in disciplines like social media, bio- and nano-informatics, Internet-of-Things (IoT), and real-time analytics, are pushing existing access and core (backbone) networks as well as Data Center Networks (DCNs) to their limits. Next generation DCNs must support continuously increasing network traffic while satisfying minimum performance requirements of latency, reliability, flexibility and scalability. Therefore, a larger number of cables (i.e., copper-cables and fiber optics) may be required in conventional wired DCNs. In addition to limiting the possible topologies, large number of cables may result into design and development problems related to wire ducting and maintenance, heat dissipation, and power consumption. To address the cabling complexity in wired DCNs, we propose OWCells, a class of optical wireless cellular data center network architectures in which fixed line of sight (LOS) optical wireless communication (OWC) links are used to connect the racks arranged in regular polygonal topologies. We present the OWCell DCN architecture, develop its theoretical underpinnings, and investigate routing protocols and OWC transceiver design. To realize a fully wireless DCN, servers in racks must also be connected using OWC links. There is, however, a difficulty of connecting multiple adjacent network components, such as servers in a rack, using point-to-point LOS links. To overcome this problem, we propose and validate the feasibility of an FSO-Bus to connect multiple adjacent network components using NLOS point-to-point OWC links. Finally, to complete the design of the OWC transceiver, we develop a new class of strictly and rearrangeably non-blocking multicast optical switches in which multicast is performed efficiently at the physical optical (lower) layer rather than upper layers (e.g., application layer). Advisors: Jitender S. Deogun and Dennis R. Alexande

Automation of the tax practice of the \u2790s;

https://egrove.olemiss.edu/aicpa_guides/1022/thumbnail.jp