High-speed and Robust Integrated Silicon Nanophotonics for On-Chip Interconnects

Optical interconnects offer advantages over electrical interconnects such as higher bandwidth, low power, reduced interconnects delay, and immunity to electro-magnetic interference and signal crosstalk. However, in order for optical interconnects to be widely adopted, the technology must be made cost effective and must be simple to implement with CMOS electronics. Silicon photonics offers a great promise due to its inexpensive material and its compatibility with the current CMOS fabrication technology. Moreover, Silicon as a platform has the ability to integrate with different types of the optical components such as photodetector, modulator, light source, and waveguide to form a photonics integrated circuit. The goal of this work is to develop and fabricate devices that utilize a hybrid electronic-photonic integration to enable high performance optoelectronic computing and communication systems that overcome the barriers of electronics and dramatically enhance the performance of circuits and systems. We experimentally demonstrate a novel broadband optical time division multiplexer (OTDM) on a silicon chip. The system has a footprint× 700 micrometer and is inherently broadband with a bandwidth of over 100nm making it suitable for high-speed optical networks on chip. Also, we propose and fabricate a novel design to demultiplex the high bit rates of OTDM data using two differentially operated 5Gb/s modulators. Moreover, we propose a high-speed hybrid optical-time-division-multiplexing (OTDM) and wavelength-division-multiplexing (WDM) system that seamlessly generates high bit-rate data (\u3e200Gbit/s) from a low speed (5Gbit/s) quantum-dot mode locked laser pulse source. By utilizing time and wavelength domains, the proposed design is a promising solution for high-speed, compact and low-power consumption optical networks on chip. And finally, we experimentally demonstrate a robust, low insertion loss, compact Silicon ring resonator electro-optic modulator for Binary Phase Shift Key (BPSK) coding/decoding that encodes data in the phase of light. Our design improves significantly over recently demonstrated PSK modulator designs in terms of insertion loss and stability

Generic closed loop controller for power regulation in dual active bridge DC-DC converter with current stress minimization

This paper presents a comprehensive and generalized analysis of the bidirectional dual active bridge (DAB) DC/DC converter using triple phase shift (TPS) control to enable closed loop power regulation while minimizing current stress. The key new achievements are: a generic analysis in terms of possible conversion ratios/converter voltage gains (i.e. Buck/Boost/Unity), per unit based equations regardless of DAB ratings, and a new simple closed loop controller implementable in real time to meet desired power transfer regulation at minimum current stress. Per unit based analytical expressions are derived for converter AC RMS current as well as power transferred. An offline particle swarm optimization (PSO) method is used to obtain an extensive set of TPS ratios for minimizing the RMS current in the entire bidirectional power range of - 1 to 1 per unit. The extensive set of results achieved from PSO presents a generic data pool which is carefully analyzed to derive simple useful relations. Such relations enabled a generic closed loop controller design that can be implemented in real time avoiding the extensive computational capacity that iterative optimization techniques require. A detailed Simulink DAB switching model is used to validate precision of the proposed closed loop controller under various operating conditions. An experimental prototype also substantiates the results achieved

Modular multilevel converter with modified half-bridge submodule and arm filter for dc transmission systems with DC fault blocking capability

Although a modular multilevel converter (MMC) is universally accepted as a suitable converter topology for the high voltage dc transmission systems, its dc fault ride performance requires substantial improvement in order to be used in critical infrastructures such as transnational multi-terminal dc (MTDC) networks. Therefore, this paper proposes a modified submodule circuit for modular multilevel converter that offers an improved dc fault ride through performance with reduced semiconductor losses and enhanced control flexibility compared to that achievable with full-bridge submodules. The use of the proposed submodules allows MMC to retain its modularity; with semiconductor loss similar to that of the mixed submodules MMC, but higher than that of the half-bridge submodules. Besides dc fault blocking, the proposed submodule offers the possibility of controlling ac current in-feed during pole-to-pole dc short circuit fault, and this makes such submodule increasingly attractive and useful for continued operation of MTDC networks during dc faults. The aforesaid attributes are validated using simulations performed in MATLAB/SIMULINK, and substantiated experimentally using the proposed submodule topology on a 4-level small-scale MMC prototype

A systems approach to determine how Toxoplasma gondii Infection causes neuropsychiatric disease

This thesis was previously held under moratorium from 16/03/2020 to 16/03/2022T. gondii infection acquired during life has been associated with psychoneurological disease in humans and behavioural changes in mice. However, less is known about the potential of congenitally acquired T. gondii infection, or for maternal T. gondii infection induced immune activation, to cause psychoneurological disease. The studies described herein, using LCMS (Liquid chromatography–mass spectrometry) demonstrate that adult acquired infection alters the neurochemistry and transcriptome of the brains of BALB/c mice. Notable changes to tryptophan, purine, arginine and carnitine metabolism were observed in infected mice. Congenitally infected and mice exposed to the maternal immune response to T. gondii, but not congenitally infected were found to have decreased mobility compared with control mice. Congenital T. gondii infection resulted in similar alterations in the neurochemistry of mice as seen in adult acquired infections. Some of these changes were observed, including tryptophan metabolism in mice exposed to the maternal immune response to T. gondii, but not congenitally infected. Both adult acquired T. gondii and congenital infection altered the brain transcriptome of mice relative to control uninfected mice with notable changes seen to transcripts of many immunologically important genes and enzymes in some of the metabolic pathways identified by LCMS. In addition, both adult acquired T. gondii infection, congenital infection and maternal exposure to different degrees were found to induce changes in a number of additional transcripts previously associated with psychoneurological diseases. These results demonstrate that maternal exposure to T. gondii infection during pregnancy induces a subset of neurochemical and transcriptomic changes found in mice with adult acquired and congenital T. gondii infection. The results therefore reinforce the potential of maternal immune activation to affect psychoneurological diseases and implicate T. gondii as a potential aetiological agent of this process.T. gondii infection acquired during life has been associated with psychoneurological disease in humans and behavioural changes in mice. However, less is known about the potential of congenitally acquired T. gondii infection, or for maternal T. gondii infection induced immune activation, to cause psychoneurological disease. The studies described herein, using LCMS (Liquid chromatography–mass spectrometry) demonstrate that adult acquired infection alters the neurochemistry and transcriptome of the brains of BALB/c mice. Notable changes to tryptophan, purine, arginine and carnitine metabolism were observed in infected mice. Congenitally infected and mice exposed to the maternal immune response to T. gondii, but not congenitally infected were found to have decreased mobility compared with control mice. Congenital T. gondii infection resulted in similar alterations in the neurochemistry of mice as seen in adult acquired infections. Some of these changes were observed, including tryptophan metabolism in mice exposed to the maternal immune response to T. gondii, but not congenitally infected. Both adult acquired T. gondii and congenital infection altered the brain transcriptome of mice relative to control uninfected mice with notable changes seen to transcripts of many immunologically important genes and enzymes in some of the metabolic pathways identified by LCMS. In addition, both adult acquired T. gondii infection, congenital infection and maternal exposure to different degrees were found to induce changes in a number of additional transcripts previously associated with psychoneurological diseases. These results demonstrate that maternal exposure to T. gondii infection during pregnancy induces a subset of neurochemical and transcriptomic changes found in mice with adult acquired and congenital T. gondii infection. The results therefore reinforce the potential of maternal immune activation to affect psychoneurological diseases and implicate T. gondii as a potential aetiological agent of this process

Electro-absorption of silicene and bilayer graphene quantum dots

We study numerically the optical properties of low-buckled silicene and AB-stacked bilayer graphene quantum dots subjected to an external electric field, which is normal to their surface. Within the tight-binding model, the optical absorption is calculated for quantum dots, of triangular and hexagonal shapes, with zigzag and armchair edge terminations. We show that in triangular silicene clusters with zigzag edges a rich and widely tunable infrared absorption peak structure originates from transitions involving zero energy states. The edge of absorption in silicene quantum dots undergoes red shift in the external electric field for triangular clusters, whereas blue shift takes place for hexagonal ones. In small clusters of bilayer graphene with zigzag edges the edge of absorption undergoes blue/red shift for triangular/hexagonal geometry. In armchair clusters of silicene blue shift of the absorption edge takes place for both cluster shapes, while red shift is inherent for both shapes of the bilayer graphene quantum dots.Comment: 7 pages, 7 figure

Assessment of the Primary and Intermediate School Staffs’ Knowledge, Attitude and Practice on Care of Children with Type 1 Diabetes at School, Al-Jouf, Saudi Arabia

Background: Children with diabetes type 1 (T1DM) need close monitoring for their blood glucose, food intake, insulin therapy and physical activity during school hours in order to guard against the development of acute and long-term complications.Objectives: To evaluate the current situation of management of T1DM in primary and intermediate schools children through assessment of the working staffs' attitude, knowledge and practice at Al-Jouf, Saudi Arabia. Materials and Methods: This descriptive cross-sectional study enrolled consented voluntarily participating working staffs from primary and intermediate schools in Al-Jouf region, Saudia Arabia. A questionnaire (included 23 questions) testing knowledge, attitudes and practice regarding T1DM and care of diabetic children was used.Results: 744 teachers were studied (62.1% females) where58.1%of them were working in primary schools. Of all, 69% were class teachers, 20.4% administrators, 8.6% school counselors, and 2% physical education teachers.75.4% of the participants had adequate general knowledge about diabetes. Only 43.78% of the respondents had specific knowledge about diabetes in the school and teachers with a family diabetic patient showed higher knowledge about diabetes vs. their counterparts. Only 16.0%of the participants reported that their schools have trained personnel in diabetes. Large proportion of study teachers' (94%) was willing to join a training program for care of diabetic students. Of the total group of teachers, 665 support recruitment of a school nurse. Conclusion: Diabetes care training programs for school teachers and staffs, availability of school nurses and instigating collaboration between the diabetic center and the school is essential for safety of such diabetes student patients in the schools.Keywords: Type 1 Diabetes mellitus, School teachers, Training programs, Diabetes care, Knowledge about diabetes, School nurse, Diabetes care at the school

The Rules of Procedure and Evidence in front of International Criminal Courts: a system sui generis

International Criminal Courts have been created to prosecute individuals allegedly accused of specific crimes such as war crimes, genocide, ethnic cleansing, and the judgment of these crimes is only endorsed by these Courts. A lot has been written concerning the procedures of prosecution; however, few jurists have dealt with the rules of evidence. Our goal is to give a thorough knowledge of the method used by those specific legal Institutions in the collecting and the processing of evidence to decide their judgment. In a first part, we have tried to shape a general definition of the notion of 'evidence' in International Criminal Law, bearing in mind that this judicial system is at the same time an internationalized and an independent one. In a second part, the analysis focused on the processing of evidence in trials before the International Criminal Courts, mainly confidentiality of evidence; these must not be shown out of the trial Chamber, all means to bring evidence is possible, the protection of witnesses, and the absolute independence of judges to consider the validity of evidence. The study has emphasized on the newness of this legal system and on the necessity of filling up judicial voids. Key-words: International Criminal Courts, system of evidence, Rules of procedure and evidence, the Statute of Rome, UN Resolutions

Characterization of regulatory sequences in alternative promoters of hypermethylated genes associated with tumor resistance to cisplatin

The development of cisplatin resistance in human cancers is controlled by multiple genes and leads to therapeutic failure. Hypermethylation of specific gene promoters is a key event in clinical resistance to cisplatin. Although the usage of multiple promoters is frequent in the transcription of human genes, the role of alternative promoters and their regulatory sequences have not yet been investigated in cisplatin resistance genes. In a new approach, we hypothesized that human cancers exploit the specific transcription factor-binding sites (TFBS) and CpG islands (CGIs) located in the alternative promoters of certain genes to acquire platinum drug resistance. To provide a useful resource of regulatory elements associated with cisplatin resistance, we investigated the TFBS and CGIs in 48 alternative promoters of 14 hypermethylated cisplatin resistance genes previously reported. CGIs prone to methylation were identified in 28 alternative promoters of 11 hypermethylated genes. The majority of alternative promoters harboring CGIs (93%) were clustered in one phylogenetic subclass, whereas the ones lacking CGIs were distributed in two unrelated subclasses. Regulatory sequences, initiator and TATA-532 prevailed over TATA-8 and were found in all the promoters. B recognition element (BRE) sequences were present only in alternative promoters harboring CGIs, but CCAAT and TAACC were found in both types of alternative promoters, whereas downstream promoter element sequences were significantly less frequent. Therefore, it was hypothesized that BRE and CGI sequences co-localized in alternative promoters of cisplatin resistance genes may be used to design molecular markers for drug resistance. A more extensive knowledge of alternative promoters and their regulatory elements in clinical resistance to cisplatin is likely to usher novel avenues for sensitizing human cancers to treatment.Cancer Prevention and Research Institute of Texas (CPRIT; no. RP130266