Properties of Graphene: A Theoretical Perspective

In this review, we provide an in-depth description of the physics of monolayer and bilayer graphene from a theorist's perspective. We discuss the physical properties of graphene in an external magnetic field, reflecting the chiral nature of the quasiparticles near the Dirac point with a Landau level at zero energy. We address the unique integer quantum Hall effects, the role of electron correlations, and the recent observation of the fractional quantum Hall effect in the monolayer graphene. The quantum Hall effect in bilayer graphene is fundamentally different from that of a monolayer, reflecting the unique band structure of this system. The theory of transport in the absence of an external magnetic field is discussed in detail, along with the role of disorder studied in various theoretical models. We highlight the differences and similarities between monolayer and bilayer graphene, and focus on thermodynamic properties such as the compressibility, the plasmon spectra, the weak localization correction, quantum Hall effect, and optical properties. Confinement of electrons in graphene is nontrivial due to Klein tunneling. We review various theoretical and experimental studies of quantum confined structures made from graphene. The band structure of graphene nanoribbons and the role of the sublattice symmetry, edge geometry and the size of the nanoribbon on the electronic and magnetic properties are very active areas of research, and a detailed review of these topics is presented. Also, the effects of substrate interactions, adsorbed atoms, lattice defects and doping on the band structure of finite-sized graphene systems are discussed. We also include a brief description of graphane -- gapped material obtained from graphene by attaching hydrogen atoms to each carbon atom in the lattice.Comment: 189 pages. submitted in Advances in Physic

Urban Biodiversity and Landscape Ecology: Patterns, Processes and Planning

Effective planning for biodiversity in cities and towns is increasingly important as urban areas and their human populations grow, both to achieve conservation goals and because ecological communities support services on which humans depend. Landscape ecology provides important frameworks for understanding and conserving urban biodiversity both within cities and considering whole cities in their regional context, and has played an important role in the development of a substantial and expanding body of knowledge about urban landscapes and communities. Characteristics of the whole city including size, overall amount of green space, age and regional context are important considerations for understanding and planning for biotic assemblages at the scale of entire cities, but have received relatively little research attention. Studies of biodiversity within cities are more abundant and show that longstanding principles regarding how patch size, configuration and composition influence biodiversity apply to urban areas as they do in other habitats. However, the fine spatial scales at which urban areas are fragmented and the altered temporal dynamics compared to non-urban areas indicate a need to apply hierarchical multi-scalar landscape ecology models to urban environments. Transferring results from landscape-scale urban biodiversity research into planning remains challenging, not least because of the requirements for urban green space to provide multiple functions. An increasing array of tools is available to meet this challenge and increasingly requires ecologists to work with planners to address biodiversity challenges. Biodiversity conservation and enhancement is just one strand in urban planning, but is increasingly important in a rapidly urbanising world

A field inventory and collections summary of herpetofauna from the Sutter Buttes, an inland island within California\u27s Great Central Valley

The Sutter Buttes (Buttes) are a small, isolated mountain range in the Great Central Valley of California. Systematic study of the fauna and flora of this unique habitat has been limited by the private ownership of the entire mountain range. As a result, much of our knowledge about the herpetofauna of the Buttes is based on isolated observations and scattered museum records, most over 4 decades old. In this study, we present an updated inventory of the herpetofauna of the Buttes, based on a 2-year field survey within the boundaries of the first publicly protected property within the Buttes (Sutter Buttes State Park) and a comprehensive survey of museum specimens. The objective of this study was to develop a current herpetofaunal species list for the Buttes as a whole and the park specifically. We verify the occurrence of 16 previously identified herpetofaunal species within the park and provide evidence for 3 additional species. We also provide the first record of the widely invasive Pond Slider (Trachemys scripta); clarify the status of a previous misidentification of a federally threatened species, Giant Gartersnake (Thamnophis gigas); and provide evidence for the probable extirpation of 2 California Species of Special Concern, the Foothill Yellow-Legged Frog (Rana boylii) and Blainville’s Horned Lizard (Phrynosoma blainvillii). Therefore, our species list for the Buttes includes 20 herpetofaunal species. Museum specimens from the Buttes are located at 8 museums, with the majority at the California State University, Chico Vertebrate Museum. Sixteen of the 22 herpetofauna species extant or recently extirpated from the Buttes are represented by museum vouchers, with only 11 having tissue samples. This study sets an updated baseline for the further study and monitoring that will be required to facilitate effective management and conservation of the unique Sutter Buttes.Sutter Buttes (Buttes) es una pequeña y aislada cordillera montañosa en el Gran Valle Central de California. El estudio sistemático de la fauna y la flora de este hábitat único se ha visto limitado debido a que toda la cordillera es propiedad privada. Como resultado, gran parte del conocimiento de la herpetofauna de la cordillera se basa en observaciones aisladas y registros dispersos de museo, la mayoría con más de cuatro décadas de antigüedad. En este estudio, presentamos un inventario actualizado de la herpetofauna de la cordillera, basado en un estudio de campo de dos años dentro de los límites de la primera propiedad de protección pública en la zona (Sutter Buttes State Park) y en una exhaustiva investigación de especímenes de museo. El objetivo de este estudio fue crear un listado de especies de herpetofauna presentes actualmente en la zona en general y en el parque en específico. Verificamos 16 especies de herpetofauna, previamente identificadas, en el Parque y mostramos evidencia de tres especies adicionales en el Parque. También proporcionamos el primer registro de la tortuga invasora Jicotea de Estanque (Trachemys scripta), clarificamos el estado de un error de identificación previo de una especie, amenazada a nivel federal, la serpiente Jarretera Gigante (Thamnophis gigas), y aportamos pruebas de la probable extirpación de dos especies de interés especial para California, la Rana Patas Amarillas de las Estribaciónes (Rana boylii) y el Camaleón de Blainville (Phrynosoma blainvillii). Por lo tanto, nuestro listado de especies para la cordillera incluye 20 especies de herpetofauna. Los especímenes de museo de la cordillera se encuentran en ocho museos, la mayoría en Museo de Vertebrados de Chico en la Universidad Estatal de California. Dieciseis de las 22 especies de herpetofauna existentes, o recientemente extirpadas, de la cordillera están representadas por comprobantes de museo, sólo 11 de ellas con muestras de tejido. Este estudio establece una base actualizada para su estudio y seguimiento futuro que será necesario para facilitar la gestión y conservación de una zona única como Sutter Buttes

Electromechanical and biological evaluations of 0.94Bi0.5Na0.5TiO3–0.06BaTiO3 as a lead-free piezoceramic for implantable bioelectronics

Smart implantable electronic medical devices are being developed to deliver healthcare that is more connected, personalised, and precise. Many of these implantables rely on piezoceramics for sensing, communication, energy autonomy, and biological stimulation, but the piezoceramics with the strongest piezoelectric coefficients are almost exclusively lead-based. In this article, we evaluate the electromechanical and biological characteristics of a lead-free alternative, 0.94Bi0.5Na0.5TiO3–0.06BaTiO3 (BNT-6BT), manufactured via two synthesis routes: the conventional solid-state method (PIC700) and tape casting (TC-BNT-6BT). The BNT-6BT materials exhibited soft piezoelectric properties, with d33 piezoelectric coefficients that were inferior to commonly used PZT (PIC700: 116 pC/N; TC-BNT-6BT: 121 pC/N; PZT-5A: 400 pC/N). The material may be viable as a lead-free substitute for soft PZT where moderate performance losses up to 10 dB are tolerable, such as pressure sensing and pulse-echo measurement. No short-term harmful biological effects of BNT-6BT were detected and the material was conducive to the proliferation of MC3T3-E1 murine preosteoblasts. BNT-6BT could therefore be a viable material for electroactive implants and implantable electronics without the need for hermetic sealing

Changes in Plasma Growth Differentiation Factor-15 After Laparoscopic Sleeve Gastrectomy in Morbidly Obese Patients: A Prospective Study [Corrigendum]

Salman A, Shaaban HED, Salman M, et al. J Inflamm Res. 2021;14:1365-1373. The authors have advised that in “GDF15 Assay” section on page 1368, the second sentence on the left panel, should read from “The serum was extracted at 80 Celsius for 10 minutes, after an immediate centrifuge at 3000 rpm, waiting for hormone analysis.” to “Plasma extracted after 10 min centrifugation at 3000 rpm and stored at - 80 Celsius”. The authors apologized for this error

A survey of green plant tRNA 3'-end processing enzyme tRNase Zs, homologs of the candidate prostate cancer susceptibility protein ELAC2

<p>Abstract</p> <p>Background</p> <p>tRNase Z removes the 3'-trailer sequences from precursor tRNAs, which is an essential step preceding the addition of the CCA sequence. tRNase Z exists in the short (tRNase Z^S) and long (tRNase Z^L) forms. Based on the sequence characteristics, they can be divided into two major types: bacterial-type tRNase Z^Sand eukaryotic-type tRNase Z^L, and one minor type, <it>Thermotoga maritima </it>(TM)-type tRNase Z^S. The number of tRNase Zs is highly variable, with the largest number being identified experimentally in the flowering plant <it>Arabidopsis thaliana</it>. It is unknown whether multiple tRNase Zs found in <it>A. thaliana </it>is common to the plant kingdom. Also unknown is the extent of sequence and structural conservation among tRNase Zs from the plant kingdom.</p> <p>Results</p> <p>We report the identification and analysis of candidate tRNase Zs in 27 fully sequenced genomes of green plants, the great majority of which are flowering plants. It appears that green plants contain multiple distinct tRNase Zs predicted to reside in different subcellular compartments. Furthermore, while the bacterial-type tRNase Z^Ss are present only in basal land plants and green algae, the TM-type tRNase Z^Ss are widespread in green plants. The protein sequences of the TM-type tRNase Z^Ss identified in green plants are similar to those of the bacterial-type tRNase Z^Ss but have distinct features, including the TM-type flexible arm, the variant catalytic HEAT and HST motifs, and a lack of the PxKxRN motif involved in CCA anti-determination (inhibition of tRNase Z activity by CCA), which prevents tRNase Z cleavage of mature tRNAs. Examination of flowering plant chloroplast tRNA genes reveals that many of these genes encode partial CCA sequences. Based on our results and previous studies, we predict that the plant TM-type tRNase Z^Ss may not recognize the CCA sequence as an anti-determinant.</p> <p>Conclusions</p> <p>Our findings substantially expand the current repertoire of the TM-type tRNase Z^Ss and hint at the possibility that these proteins may have been selected for their ability to process chloroplast pre-tRNAs with whole or partial CCA sequences. Our results also support the coevolution of tRNase Zs and tRNA 3'-trailer sequences in plants.</p

COVIDiSTRESS Global Survey dataset on psychological and behavioural consequences of the COVID-19 outbreak

This N = 173,426 social science dataset was collected through the collaborative COVIDiSTRESS Global Survey – an open science effort to improve understanding of the human experiences of the 2020 COVID-19 pandemic between 30th March and 30th May, 2020. The dataset allows a cross-cultural study of psychological and behavioural responses to the Coronavirus pandemic and associated government measures like cancellation of public functions and stay at home orders implemented in many countries. The dataset contains demographic background variables as well as measures of Asian Disease Problem, perceived stress (PSS-10), availability of social provisions (SPS-10), trust in various authorities, trust in governmental measures to contain the virus (OECD trust), personality traits (BFF-15), information behaviours, agreement with the level of government intervention, and compliance with preventive measures, along with a rich pool of exploratory variables and written experiences. A global consortium from 39 countries and regions worked together to build and translate a survey with variables of shared interests, and recruited participants in 47 languages and dialects. Raw plus cleaned data and dynamic visualizations are available

COVIDiSTRESS Global Survey dataset on psychological and behavioural consequences of the COVID-19 outbreak

This N = 173,426 social science dataset was collected through the collaborative COVIDiSTRESS Global Survey – an open science effort to improve understanding of the human experiences of the 2020 COVID-19 pandemic between 30th March and 30th May, 2020. The dataset allows a cross-cultural study of psychological and behavioural responses to the Coronavirus pandemic and associated government measures like cancellation of public functions and stay at home orders implemented in many countries. The dataset contains demographic background variables as well as measures of Asian Disease Problem, perceived stress (PSS-10), availability of social provisions (SPS-10), trust in various authorities, trust in governmental measures to contain the virus (OECD trust), personality traits (BFF-15), information behaviours, agreement with the level of government intervention, and compliance with preventive measures, along with a rich pool of exploratory variables and written experiences. A global consortium from 39 countries and regions worked together to build and translate a survey with variables of shared interests, and recruited participants in 47 languages and dialects. Raw plus cleaned data and dynamic visualizations are available