Mathematical simulation of graphene with modified c-c bond length and transfer energy

In nanotechnology research, allotropes of carbon like Graphene, Fullerene (Buckyball) and Carbon nanotubes are widely used due to their remarkable properties. Electrical and mechanical properties of those allotropes vary with their molecular geometry. This paper is specially based on modeling and simulation of graphene in order to calculate energy band structure in k space with varying the C-C bond length and C-C transfer energy. Significant changes have been observed in the energy band structure of graphene due to variation in C-C bond length and C-C transfer energy. In particular, this paper focuses over the electronic structure of graphene within the frame work of tight binding approximation. It has been reported that conduction and valence states in graphene only meet at two points in k-space and that dispersion around these special points is conical. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2305

Mathematical simulation of graphene with modified c-c bond length and transfer energy

In nanotechnology research, allotropes of carbon like Graphene, Fullerene (Buckyball) and Carbon nanotubes are widely used due to their remarkable properties. Electrical and mechanical properties of those allotropes vary with their molecular geometry. This paper is specially based on modeling and simulation of graphene in order to calculate energy band structure in k space with varying the C-C bond length and C-C transfer energy. Significant changes have been observed in the energy band structure of graphene due to variation in C-C bond length and C-C transfer energy. In particular, this paper focuses over the electronic structure of graphene within the frame work of tight binding approximation. It has been reported that conduction and valence states in graphene only meet at two points in k-space and that dispersion around these special points is conical. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2305

Tunable Anti-Guiding Factor and Optical Gain of InGaAlAs/InP Nano-Heterostructure under Internal Strain

This paper reports about the study of tunable anti-guiding factor and gain spectra of type-I GRIN (Graded Refractive Index) compressively strained InGaAlAs/InP nano-heterostructure. Through the modeling and mathematical simulation, the tuning behaviors of optical gain, differential gain and refractive index-change with carrier densities have been studied in the presence of internal strain which occurs due to lattice mismatch. According to the results, both the anti-guiding factor and optical gain are enhanced as increase in the percentage compressively strain. The lasing wavelength has also been found to shift towards lower values with increasing strain. These studies explain the tunability of the studied heterostructure and mostly utilized in optical fiber based communication systems

Analytical Study of Graphene as a Novel Piezoresistive Material for MEMS Pressure Sensor Application

The one-atom thick layer of carbon has been investigated with its unique exclusive property such as high thermal conductivity due to the high velocity of electron and exceptional electrical conductivity as well as mechanical strength. Due to its extraordinary properties; graphene put back many conventional materials to due smart, sensitive applications. As graphene has no band gap (Eg ~0 eV) but there is one method to induce a band gap by applying strain and each specific strain direction will create a unique band gap structure, in return it give signals which can be sensed by the device. The device can be operated either optically or electrically at different pressure levels up to Tera Pascal range thereby providing designers and engineers with a versatile sensing solution. To fabricate MEMS sensor based on a single layer of graphene, the piezoresistive pressure is becoming the most devastating problem up to nanoscale without damaging and high quality, defect free graphene. In this paper, we discussed the issues and cost effective solutions to integrate MEMS/NEMS pressure sensor device. We also compared the sensor performance with traditional piezoresistive materials

PURA syndrome : clinical delineation and genotype-phenotype study in 32 individuals with review of published literature

Background De novo mutations in PURA have recently been described to cause PURA syndrome, a neurodevelopmental disorder characterised by severe intellectual disability (ID), epilepsy, feeding difficulties and neonatal hypotonia. Objectives T o delineate the clinical spectrum of PURA syndrome and study genotype-phenotype correlations. Methods Diagnostic or research-based exome or Sanger sequencing was performed in individuals with ID. We systematically collected clinical and mutation data on newly ascertained PURA syndrome individuals, evaluated data of previously reported individuals and performed a computational analysis of photographs. We classified mutations based on predicted effect using 3D in silico models of crystal structures of Drosophila-derived Pur-alpha homologues. Finally, we explored genotypephenotype correlations by analysis of both recurrent mutations as well as mutation classes. Results We report mutations in PURA (purine-rich element binding protein A) in 32 individuals, the largest cohort described so far. Evaluation of clinical data, including 22 previously published cases, revealed that all have moderate to severe ID and neonatal-onset symptoms, including hypotonia (96%), respiratory problems (57%), feeding difficulties (77%), exaggerated startle response (44%), hypersomnolence (66%) and hypothermia (35%). Epilepsy (54%) and gastrointestinal (69%), ophthalmological (51%) and endocrine problems (42%) were observed frequently. Computational analysis of facial photographs showed subtle facial dysmorphism. No strong genotype-phenotype correlation was identified by subgrouping mutations into functional classes. Conclusion We delineate the clinical spectrum of PURA syndrome with the identification of 32 additional individuals. The identification of one individual through targeted Sanger sequencing points towards the clinical recognisability of the syndrome. Genotype-phenotype analysis showed no significant correlation between mutation classes and disease severity.Peer reviewe

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries