186,324 research outputs found
Environmentally Friendly Graphene Inks for Touch Screen Sensors
No full textGraphene-based materials have attracted significant attention in many technological fields, but scaling up graphene-based technologies still faces substantial challenges. High-throughput top-down methods generally require hazardous, toxic, and high-boiling-point solvents. Here, an efficient and inexpensive strategy is proposed to produce graphene dispersions by liquid-phase exfoliation (LPE) through a combination of shear-mixing (SM) and tip sonication (TS) techniques, yielding highly concentrated graphene inks compatible with spray coating. The quality of graphene flakes (e.g., lateral size and thickness) and their concentration in the dispersions are compared using different spectroscopic and microscopy techniques. Several approaches (individual SM and TS, and their combination) are tested in three solvents (N-methyl-2-pyrrolidone, dimethylformamide, and cyrene). Interestingly, the combination of SM and TS in cyrene yields high-quality graphene dispersions, overcoming the environmental issues linked to the other two solvents. Starting from the cyrene dispersion, a graphene-based ink is prepared to spray-coat flexible electrodes and assemble a touch screen prototype. The electrodes feature a low sheet resistance (290 Ω □−1) and high optical transmittance (78%), which provide the prototype with a high signal-to-noise ratio (14 dB) and multi-touch functionality (up to four simultaneous touches). These results illustrate a potential pathway toward the integration of LPE-graphene in commercial flexible electronics
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The impact of light exposure in the methylome profile of Pseudomonas aeruginosa
No full textDissertação de mestrado em Molecular GeneticsPseudomonas aeruginosa are ubiquitous opportunistic pathogenic bacteria known to cause infections in immunocompromised individuals. These bacteria face environmental challenges, including light fluctuations, prompting adaptive responses. However, the impact of light exposure on pathogenicity traits of P. aeruginosa remains unclear. Reports suggest that gDNA N6-methyladenine (6mA) methylation, frequently found in prokaryotes, may impact virulence and pathogenicity molecular mechanisms.
The main goal of this exploratory study was to elucidate the light-exposure-dependent methylome profile of clinical isolate P. aeruginosa HB15. Upon cultivation of HB15 strain under restricted light or dark conditions, physiological parameters, proteome and methylome profiles were compared. Bacterial doubling time, during exponential phase, was found to be 16 % higher under light exposure conditions, as well as swimming motility. In contrast, swarming and twitching motilities seemed to be enhanced under dark conditions. Proteomic profiling revealed a light-dependent altered content of proteins contributing to the virulence of P. aeruginosa bacteria, including proteins involved in motility, antibiotic resistance, defence against oxidative stress and signal transduction mechanisms (e.g. multidrug efflux pumps and peroxiredoxins). Significantly, two putative adenine methyltransferases were found to have different abundance levels depending on light grown conditions, suggesting that light exposure may modulate epigenomic dynamics. The inspection of the genome wide DNA methylation profiles, using Oxford Nanopore technology revealed that, under light exposure, several genes linked to pathogenic mechanisms, including antibiotic resistance, motility, biofilm formation and quorum sensing signalling, were more extensively methylated.
Our findings suggest that light exposure variations influence virulence and antibiotic resistance of P. aeruginosa, putatively shaped by DNA methylation dynamics. Albeit extensive studies on P. aeruginosa pathogenicity and antibiotic resistance assessment have been carried out, so far, the potential impact of DNA methylation dynamics on those traits has been overlooked. Therefore, this pioneer study highlights the need to better understand the intricate DNA methylation dynamics of P. aeruginosa and its association to adaptation mechanisms that may influence the expressed pathogenicity traits.Pseudomonas aeruginosa são bactérias patogénicas, ubíquas e oportunistas, conhecidas por causarem infeções em indivíduos imunocomprometidos. Estas bactérias enfrentam desafios ambientais, incluindo oscilações luminosas, que induzem respostas adaptativas. Contudo, o impacto da exposição à luz em traços patogénicos de P. aeruginosa é incerto. Estudos sugerem que metilações N6-metiladenina (6mA) no ADN, frequentemente encontradas em procariotas, podem impactar virulência e mecanismos moleculares de patogenicidade.
O objetivo principal deste estudo exploratório foi avaliar o impacto da exposição à luz no perfil de metiloma do isolado clínico P. aeruginosa HB15. Após o crescimento da estirpe HB15 em condições restritas de luz ou escuro, foram comparados parâmetros fisiológicos, e perfis de proteoma e metiloma. Verificou-se que o tempo de duplicação, durante a fase exponencial, foi 16 % mais elevado na presença de luz, verificando-se o mesmo na motilidade tipo swimming. Contudo, as motilidades swarming e twitching aumentaram no escuro. A análise proteómica revelou alterações dependentes da exposição à luz, nomeadamente em proteínas associadas a motilidade, resistência a antibióticos, defesa contra stress oxidativo e mecanismos de transdução de sinais (ex: bombas de efluxo de multidrogas e peroxirredoxinas). Além disso, duas adeninas metiltransferases putativas exibiram níveis de abundância dependentes da exposição à luz, sugerindo que a luz pode modular dinâmicas epigenéticas. A análise dos perfis epigenómicos, utilizando tecnologia Oxford Nanopore, revelou que, sob exposição luminosa, vários genes associados a mecanismos patogénicos, entre os quais resistência a antibióticos, motilidade, formação de biofilmes e sinalização de quorum sensing, se mostraram mais extensivamente metilados.
Os nossos resultados sugerem que variações luminosas influenciam a virulência e a resistência a antibióticos de P. aeruginosa, putativamente modeladas pelas dinâmicas de metilação do ADN. Embora existam estudos extensivos sobre a patogenicidade e a resistência aos antibióticos de P. aeruginosa, até agora, o potencial impacto da dinâmica da metilação do ADN nestas características tem sido negligenciado. Assim, este estudo pioneiro realça a necessidade de entender a dinâmica intrincada da metilação do ADN de P. aeruginosa e a sua associação a mecanismos de adaptação que podem influenciar as características de patogenicidade expressas
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Dr. Edward P. Wimberly, ITC, July 2011
No full textThis video is a conversation with Dr. Edward P. Wimberly. Dr. Wimberly talks about his book, "No Shame in Wesley's Gospel: A Twenty-First Century Pastoral Gospel". Brad Ost, AUC Woodruff Library, is the interviewer
Fabrico de células solares de filme de silício amorfo higrogenado utilizando a técnica de deposição química de vapores assistida por filamento aquecido
No full textDissertação de mestrado em Física de Materiais Avançados (área de especialização em Materiais Funcionais para a Nano e Microtecnologias)É apresentado um estudo da fabricação de células solares de filme fino na estrutura de diodos superstrato p-i-n em substratos de plástico à temperatura de 150ºC, usando
diferentes camadas de absorção (camada i). A estrutura típica da célula solar fabricada nesse trabalho foi feita com sucessivas camadas: PEN/GZO/p/buffer/i/n/metal. GZO é
uma camada transparente condutora janela produzida com Óxido de Zinco dopada com
Gálio e o buffer é uma camada de silício amorfo de hiato de energia proibida (gap)
maior ~10nm de espessura. Células solares flexíveis, depositadas totalmente por
deposição química de vapores assistida por plasma assistido de radio freqüência (RFPECVD) em plástico do tipo PEN, tiveram eficiência de 5.0%, JSC = 11.2 mA/cm2 e VOC
= 0.830 V. Células solares similares depositadas sobre PEN, porém com a camada –i
depositada por deposição química de vapores assistida por filamento aquecido (HWCVD),
tiveram eficiência de 4.53%, JSC = 12.7 mA/cm2 e VOC = 0.699 V. Células
solares fabricadas em PEN e vidro Asahi-U têm características comparáveis, no entanto, o melhor fill factor obtido no PEN é 55.6% contra 60.1% no vidro.A study of the fabrication of thin-film silicon solar cells in the p-i-n superstrate diode
configuration on plastic substrates at a temperature of 150 ºC, using different absorbing
i-layers, is presented. In this work a typical solar cell structure comprises the following
successive layers: PEN/GZO/p/buffer/i/n/metal. GZO is a transparent conductive
window layer made of Zinc Oxide doped with Gallium and buffer is a high-bandgap
~10 nm-thick amorphous silicon layer. Flexible solar cells deposited entirely by radiofrequency
plasma enhanced chemical vapour deposition (RF-PECVD) on PEN had a
conversion efficiency of 5.0%, JSC = 11.2 mA/cm2, and VOC = 0.830 V. Similar solar
cells on PEN but with the i-layer deposited by hot-wire chemical vapor deposition (HWCVD),
had the efficiency of 4.53%, JSC = 12.7 mA/cm2, and VOC = 0.699 V. Devices
fabricated on PEN and on Asahi-U glass have comparable characteristics. However, the
best fill factor obtained on PEN is 55.6% whereas on glass it is 60.1%
Author Rights and Scholarly Publishing
No full textOriginally posted at
http://blog.library.gsu.edu/2014/10/24/author-rights-and-scholarly-publishing/</p
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