1,721,097 research outputs found
Special Issue on Organic Electronic Bio-Devices
No full textThe aim of the present editorial is to briefly summarize the current scientific and technological accomplishments in the field of organic electronic biosensors as described in the articles published in this Special Issue. By definition, a biosensor is a robust analytical device that combines a biological recognition element (e.g., antibodies, enzymes, cells) with a transducer. Organic electronic bio-devices are considered as potentially reliable substitutes of conventional and rather expensive analytical techniques employed for several applications such as medical diagnosis, food safety and environment pollution monitoring. Some insights into the selection and immobilization of recognition elements, signal amplification, fabrication techniques and analytical performance of biosensing devices will be presented
Let Us Together Shine a Light on Women in STEM
No full textChemistry, as part of the STEM (Science, Technology, Engineering, and Mathematics) disciplines, is one of many areas where women’s potential is often still being “STEMmed”. In other words, women receive fewer opportunities both as students and in leadership positions, and hence the entire community loses out on this vast pool of talent. This ACS OmegaVirtual Issue on “Women at the Forefront of Chemistry” is our way to celebrate women’s talent in chemistry and its interfacing areas by giving the floor to 50 outstanding women scientists from all over the world who have published in ACS Omega as corresponding authors.
It is well-known that women are under-represented in the STEMs. (1) The data presented in the latest report “She Figures 2018,” one of a series of publications released since 2003 by the European Commission, offer an overview of gender (in)equality in Research and Innovation at the pan-European level. In most European Union countries examined, while the percentage of STEM female Ph.D. graduates between 2013 and 2016 grew slightly in fields such as biological sciences, environmental science, and information and communication technologies, their numbers grew at a lower rate compared to their male counterparts in several other STEM fields. The document additionally shows that the proportion of women becomes smaller and smaller, as they climb the academic career ladder. While this disparity does not only apply to STEMs, the gender gap here is even more severe, where the numbers reveal the following: women make up 32% of students and 36% of B.Sc. and M.Sc. graduates, and they make up 37% of Ph.D. students and 39% of Ph.D. graduates. As they move into academic careers, they make up 35% assistant, 28% associate, and 15% full professors, respectively. The percentage of women full professors in Europe for all the disciplines in 2016 was 24%. In 2013, these latter figures were lower, at 14% for the STEMs and 22% for all disciplines. So, while the gender gap in the academic leadership positions has reduced, this is progressing slowly, and gender parity remains far from balanced.
The increase of the share of women full professors since 2003 and over the last three years might indicate that the gender gap will close fairly quickly in Europe. (1) However, prominent studies on a broader global scale are not that optimistic. For instance, The Global Gender Gap Report 2017 (2) stated that, globally, gender parity is shifting into reverse this year for the first time since the World Economic Forum started measuring it and states more specifically “on current trends, the overall global gender gap can be closed in exactly 100 years across the 106 countries covered since the inception of the Report, compared to 83 years last year”. Additionally, the same report suggests that with the continued widening of the economic gender gap it will now not be closed for another 217 years. (2)
Along the same lines, a report by the United Nations Development Programme Gender Social Norms Index, (3) published in 2020 that gathers data from 75 countries, covering over 80% of the world’s populations, highlights how the progress toward gender equality is slowing down since 2013. The world is not on track to achieve gender equality by 2030, as foreseen 25 years ago by the Beijing Declaration and Platform for Action. (3) More regretfully, the analysis reveals that despite decades of progress close to 90% of men and women hold some degree of bias against women, thus suggesting that there still are invisible barriers that women face in achieving equality. (3)
Without the pretense to be able to analyze in the short space of an Editorial, the complex reasons why this is happening, the low share of women full professors in European academia, and their slight increase in the last three years call for two comments. The first observation is that very few women reach top academic positions. It is noteworthy that there is a similar occurrence with roughly the same share, in many different sectors of civil society, from public administration to the magistracy and in the private sector. This means that the talents of a large fraction of women that are not given the opportunity to sit in decision-making bodies and/or to shape a research group activity according to their own vision are lost. It is therefore not surprising that a variety of models and empirical studies suggest that improving gender parity may result in significant economic dividends, which vary depending on the situation of different economies and the specific challenges they are facing. The world as a whole could increase global Gross Domestic Product by US$5.3 trillion by 2025 by closing the gender gap in economic participation by 25% over the same period. (2)
Second, and importantly for this Editorial, increasing the number of women in leadership positions could enhance the “role-modeling” influence on younger women so that they consider leadership roles to be achievable and are encouraged to strive for them. For this reason, in my role as an Associate Editor at this scientific journal, ACS Omega, I advocate that everyone make an effort to shine a light on successful women in STEM, as in a sort of giant virtual resonator. Here, ACS Omega showcases the contributions to the chemistry enterprise of 50 brilliant women scientists from all over the world, some at the beginning of their career and some already established. We hope to inspire other women, and men as well, to think of Chemistry and STEM subjects as fields where everyone can contribute fruitfully and encourage those in decision-making positions to implement concrete actions aimed at speeding up the closing of the gender gap in research and innovation
Enzymatic Boolean Logic Gates toward ON/OFF Sensing
No full textIn this paper we report a combined theoretical and experimental approach to develop enzyme logic gates networks (ELGN). ELGNs were tested in solution with optical analysis of the output signals. Then, the enzymes were immobilized on a buckypaper electrode for electrochemical transduction of the output signals. Finally, the switchable electrodes were integrated in a biofuel cell as a self-powered device for the detection of sucrose in adulterated wine samples
Interface and gate bias dependent responses of sensing organic thin-film transistors
No full textThe effects of the exposure of organic thin-film transistors, comprising different organic semiconductors and gate dielectrics, to 1-pentanol are investigated. The transistor sensors exhibited an increase or a decrease of the transient source-drain current in the presence of the analyte, most likely as a result of a trapping or of a doping process of the organic active layer. The occurrence of these two effects, that can also coexist, depend on the gate-dielectric/organic semiconductor interface and on the applied gate field. Evidence of a systematic and sizable response enhancement for an OTFT sensor operated in the enhanced mode is also presented. (c) 2005 Elsevier B.V. All rights reserved
Organic biosensors and bioelectronics
No full textThe interfacing of biomaterials to electronic devices is one of the most fascinating challenge in fundamental studies as well as in the development of ultrasensitive biosensors. Important aspects connected to the field of biosensors based on electrolyte-gated organic transistors are discussed. An overview of bioelectronic thin-film transistors is herein provided along with the strategies for the deposition of the biorecognition elements on the biosensor’s transducer surface. Among the different configurations of biosensors based on thin-film transistors, particular attention is paid to the electrolyte-gated organic transistors’ based biosensors. The operation mechanism is herein highlighted, along with the definition of the main analytical figure of merits. In the last part, different electronic biosensors based on electrolyte-gated organic transistors are presented. Specific applications such as proteins detection are also discussed
Nanoscale organic and polymeric field-effect transistors as chemical sensors
No full textThis article reviews recently published work concerning improved understanding of, and advancements in, organic and polymer semiconductor vapor-phase chemical sensing. Thin-film transistor sensors ranging in size from hundreds of microns down to a few nanometers are discussed, with comparisons made of sensing responses recorded at these different channel-length scales. The vapor-sensing behavior of nanoscale organic transistors is different from that of large-scale devices, because electrical transport in a nanoscale organic thin-film transistor depends on its morphological structure and interface properties (for example injection barrier) which could be modulated by delivery of analyte. Materials used in nanoscale devices, for example nanoparticles, nanotubes, and nanowires, are also briefly summarized in an attempt to introduce other relevant nano-transducers
Self-powered logically operated fluorescent detection of hepatitis B virus (HBV)
No full textIn this study, a novel sensing strategy based on double sensing/actuating pathway is demonstrated, being capable to trigger the DNA-based AND gate for the sensitive and selective detection of hepatitis B virus DNA (HBV-DNA). Such an approach encompasses an enzymatic machinery logically operated using the variation of physiologically relevant biomarkers for liver dysfunctions. Alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) are used as inputs of an AND gate generating an output signal, namely lactate. In particular, lactate is oxidized back to pyruvate at the anodic electrode by lactate oxidase connected in mediated electron transfer through ferrocene moieties (creating an amplifying recycling mechanism). The anodic electrode is further connected with a Myrothecium verrucaria bilirubin oxidase (MvBOx) based biocathode modified with SiO2 nanoparticles (SiO2NPs) functionalized with phenyl boronic acid and trigonelline, triggering the release of quenching DNA (qDNA) upon local pH change at the electrode surface (notably, modified SiONPs gets negatively recharged upon local pH gradient releasing negatively charged DNA). Next, the released qDNA labeled with BHQ2 and detecting DNA (dDNA, labeled with FAM) are detecting HBV-DNA. The proposed biosensor can discriminate between the absence and presence of HBV-DNA setting the threshold at 0.05 fM in model buffer solutions and 1 fM in human serum. This enzymatic/DNA logic network can be of particular interest for future biomedical applications (e.g., early detection of liver cancer disease etc.). In the future development this technology could be easily integrated with a smartphone camera, allowing more user-friendly applications
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
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