bluuebunny/crossref_metadata_2025 huggingface dataset:
Whiskers 14. Morphology and Thermal Properties of Copolyesters of 4-Hydroxybenzoic Acid, Terephthalic Acid and Hydroquinone
Authors: Schwarz Gert , Zemann Uwe , Kricheldorf Hans R
Published: August 2002

In addition to the homopolyesters, poly(4-hydroxybenzoate) and poly(4-phenylene terephthalate), two series of copolyesters have been prepared with a systematic variation of the molar ratio. The first series was prepared by polycondensation of 4-acetoxybenzoic acid, terephthalic acid and acetylated hydroquinone in a liquid inert reaction medium at 400 °C. The second series was prepared under the same reaction conditions but from silylated 4-acetoxybenzoic acid and silylated terephthalic acid and showed a considerably higher 4-hydroxybenzoate/terephthalate ratio than expected from the feed ratio. The composition of these copolyesters was checked by 1H NMR spectroscopy after hydrolysis. All copolyesters proved to be highly crystalline regardless of the molar composition. WAXS measurements were conducted with synchrotron radiation up to 450 °C. These WAXS patterns indicate a gradual phase transition between 150 and 300 °C which is not detectable in the DSC curves. For the copolyesters containing > 50 mol% or 4-Hybe (4-hydrobenzoic acid) units one or two reversible first-order phase transitions were found in the DSC traces. Electron microscopy revealed that all these copolyesters are crystal powders consisting of particles of irregular shape. However, copolycondensations of silylated 4-acetoxybenzoic acid with silylated terephthalic acid and acetylated hydroquinone yielded copolyesters with a ‘potato-chip morphology’.
MALDI-TOF Characterization and Cross-Linking Study of Some Novel Polycyclic Carbonates
Authors: Mandal Humayun , Hay Allan S
Published: August 2002

Attempts were made to synthesize polycyclic carbonates by reacting C-C orthocoupled 4- t-butylphenol resins with excess triphosgene under high-dilution conditions. Under these conditions complete functionalization of the phenolic groups was not possible because of steric hindrance. Novolac-type phenol-formaldehyde resins were selected for this study because there is less steric hindrance in these systems toward the formation of the cyclic carbonates. The MALDI-TOF MS technique plays a crucial role in the detection of the absolute masses of the different oligomeric polycyclic carbonates formed. The functionalization of the hydroxy groups by formation of cyclic carbonates has also been confirmed by NMR. Our objective in the synthesis of these types of polycyclic carbonates was to obtain therming materials with a high cross-link density. When mixed with a commercial BPA polycarbonate ( Mw = 33 000) transesterification reactions take place resulting in a cross-linked system. The polycyclic carbonates were mixed with the linear polycarbonate in different proportions and cured at different temperatures by using lithium stearate as catalyst. Curing a mixture which contained 10 wt% of the polycyclic carbonates at 350 °C for 30 min resulted in a highly cross-linked system.
Synthesis and Characterization of Diaminophenylindane Based Polyimides via Ester-Acid Solution Imidization
Authors: Farr I V , Glass T E , Ji Q , McGrath J E
Published: August 2002

The solution polycondensation of 1-(4-aminophenyl)-5(6)-aminoindane (DAPI) with a number of commercially available dianhydrides using the two-step ester-acid solution imidization route is described. High molecular weight polyimides were successfully synthesized from a 1:1 molar ratio of dianhydride to diamine. These film-forming systems have high glass transition temperatures (331–368 °C) and very good short-term thermal stability as judged by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The fully cyclized polyimides are also highly soluble in common solvents.
Photophysics of Carbazole-Containing Systems. 2. Fluorescence Behaviour of Poly(N-Vinyl Carbazole) and N -Vinyl Carbazole/Methyl Acrylate Copolymer Films
Authors: Soutar Ian , Swanson Linda , Davidson Keith , Yin Jie
Published: August 2002

The fluorescence behaviour of thin films of poly( N-vinyl carbazole), PNVCz, and a series of N-vinyl carbazole/methyl acrylate, NVCz/MA, copolymers has been investigated using both steady-state and time-resolved emission techniques. The fluorescence of PNVCz at 298 K is dominated by emission from two excimeric traps. Trap I has the conventional ‘sandwich’ structure formed from two fully overlapped aromatic rings. The other (trap II) is a species involving two partially overlapped carbazole substituents. The fluorescences of the NVCz/MA copolymers contain contributions from unassociated or monomeric carbazoyl excited states which increase in prominence as the aromatic content of the system is reduced. The influence of intermolecular interactions in creating excimer traps is apparent: even at a carbazole content of 8.3 mol%, excimer emission is evident. In PNVCz and copolymers of higher aromatic contents, the microtacticity of the macromolecule exerts a dominant influence upon the photophysical behaviour of the bulk polymer despite the moderating effects of intermolecular interactions between chromophores.

As the temperature of the system is reduced, the contribution from trap II to the overall fluorescence from the polymer films increases relative to that made by emission from trap I. At 77 K, the fluorescence of PNVCz contains a significant contribution from trap II emission. At 298 K, fluorescence from the conventional excimer, trap I, dominates the steady-state emission spectrum. On the basis of observations upon time-resolved fluorescence data, it is proposed that restrictions to the reorientation of carbazole substituents which occur at low temperature serve to inhibit the conversion of a proportion of the trap II sites into fully overlapped excimers, thereby reducing depletion of the trap II population. Implicit to this explanation of the photophysical characteristics of PNVCz and the higher content NVCz/MA copolymers, is the belief that the high concentration of excimer-forming trap sites mitigates against significant energy migration between carbazole substituents which might otherwise populate the excimer traps. These observations are of importance to considerations of the photoconductivity displayed by polymers derived from NVCz.
`Chernobyl' reaches Norway: the accident, science, and the threat to cultural knowledge
Authors: Paine Robert
Published: August 2002

This report is interested in the transitions that `Chernobyl' underwent in Norway. It `arrived' as a ghastly accident: important cultural routines were disturbed, apprehension ran high, and the country waited for scientists to `repair' the accident. By the following year, `Chernobyl' was but a memory for most of the population. The scourge of radiation, however, still covered much of the countryside of central Norway. Reindeer pastures were heavily polluted, and among Saami (Lapp) groups there arose a cognitive sense of disruption to a way of life. Ambivalent relations—at times cooperative, more often adversarial—developed among the Saami in respect to the outside experts who strove to bring the radiation problem under control. The report (with anthropological fieldwork) strives to show how much of the problem of `Chernobyl', in this later phase, had to do with the different nature of the claims of two kinds of knowledge: the outside scientists' and the Saami pastoralists'.
Scientific literacy as collective praxis
Authors: Roth Wolff-Michael , Lee Stuart
Published: August 2002

In this article, we conceive of scientific literacy as a property of collective activity rather than individual minds. We think of knowing and learning science as situated in and distributed across social and material aspects of a setting. To support the proposed conception, we provide several detailed cases from our three-year multi-site ethnographic study of science in one community, featuring different types of citizens who walk a creek, interact during an environment-oriented open-house event, discuss water problems, collect data, and have different conceptions of human-environment relations. The case studies show that collectively, much more advanced forms of scientific literacy are produced than any individual (including scientists) could produce. Creating opportunities for scientific literacy to emerge from collective activity, irrespective of whether one or more participants know some basic scientific facts, presents challenges to science educators very different from teaching basic facts and skills to individuals.
Science and the contemporary visual arts
Authors: Ede Siân
Published: August 2002

Scientists and artists increasingly engage each other's work. This paper provides an initial analysis of that engagement, highlighting the challenge of materials, the fascination of scientific paradigms, the artist's ability to assist with scientific investigation, and the need to explore the political and ethical consequences of science.
Can science be at the centre of modern culture?
Authors: Holton Gerald
Published: August 2002

Increasingly, such concepts as the `End of the Modern Era', the `End of Progress', and the `End of Objectivity' have been given public exposure, originating from parts of academe and from popularizers. Far from being merely a passing phase connected with the usual fin-de-siècle preoccupations, the movement appears to signal the resurgence of an old, recurring rebellion against Enlightenment-based presuppositions of Western civilization, particularly the claim of science to lead to intersubjective (objective) knowledge. The negative impacts upon the public understanding of science are becoming evident, including among legislators of science policy. To understand the movement, a survey is given of some of the chief theorists on the question of whether science may play a central role in 20th-century culture, including Oswald Spengler, the Vienna Circle scientist-philosophers, Sigmund Freud, Isaiah Berlin, and Václav Havel.
The public image of science in the Czech and Slovak Republics
Authors: Filáčcek Adolf , Křižová-Frýdová Eva
Published: August 2002

This paper summarizes the results of a survey into the prestige of various occupations in contemporary Czechoslovak society, which was carried out in November 1990 on a representative sample of 1400 respondents in the Czech and Slovak Republics. The results show a high level of prestige of scientific (research) professions. All the five representatives of the research community finished among the top 20 professions (a total of 49 different professions were evaluated). Out of these, associate professor was third in the scale of prestige, with scientist fourth and head of a research centre tenth. The prestige of scientists did not depend statistically on the age, sex or education of respondents. From factor analysis it follows that the group of professions connected with science or research forms a relatively independent subgroup of professions assessed by respondents in a similar manner. Finally, the prestige of scientific and research professions in Czechoslovak society is much higher than scientists think it is.
Changing minds about embryo research
Authors: Mulkay Michael
Published: August 2002

Documentary sources are used to examine the parliamentary evaluation of scientific research on human embryos which took place in Britain during the 1980s. Evidence is presented to show that there was a major change in the balance of opinion in the course of the long sequence of debates which ended with the passage of the Human Fertilization and Embryology Act in 1990. It is suggested that there was a pronounced movement in favour of embryo research which was associated with a significant alteration in the social relationships between scientists and Members of Parliament and with a marked change in the way in which embryo research came to be morally justified. It is argued that the negotiations over embryo research in Parliament contributed to the clarification of the moral boundaries within which such research was to be confined and to the establishment of social mechanisms designed to maintain the integrity of these boundaries.
German genetic engineering scientists and the German public: complementary perceptions in a changing European context
Authors: Rabino Isaac
Published: August 2002

In a 1991 survey, we assessed how genetic engineering scientists in Europe viewed the influence of public attention on their field. In almost every respect, by far the most negative responses came from scientists in West Germany: only 10% perceived public attention as beneficial and 63% perceived it as harmful; more than 90% worried that Germany could lose its competitive edge in this field; and more than 70% viewed national regulations as too strict. Open-ended comments from researchers reinforce the negative German picture. Major complaints include ill-trained, incompetent local enforcement offices often using delaying tactics to avoid making decisions; unnecessary compulsory courses; massive bureaucracies; endless paperwork; and mandatory `safety offices' that only generate more paper. Scientists and journalists point to three causes for public opposition: one-sided media coverage, sensitivity to World War II history (eugenics), and powerful activist opposition. The `Eurobarometer' 1991 and 1993 surveys of the public show that German scientists' perceptions of the public attitude are based on reality: public acceptance is low, and has been deteriorating further since 1991. Although the national German laws regulating biotechnology have now been relaxed, it remains to be seen whether the attitude of the public, as well as local and state-level regulations, will follow the same trend. To improve public acceptance, German genetic engineering scientists may need to make a long-term commitment to communication and education about all aspects of their field, including risks. Although there is no guarantee that this will bring quick results (it apparently has not done so in the Netherlands, for instance), cases such as Denmark suggest that it may improve acceptance in the long term.
`Science journalism' without science journalists: notes on a Norwegian media paradox
Authors: Eide Martin , Ottosen Rune
Published: August 2002

This article discusses recent developments of the relationship between scientists and journalists in Norway, a country without a tradition of science journalism. A general professional upgrading among journalists is now accompanied by a growing interest in science coverage. Paradoxically, this coverage is already extensive, though as yet not of high quality. For a proper understanding of the traditions as well as new tendencies within science coverage, we discuss cultures and traditions—within academic as well as in the media—and specific socio-historical contexts. The discussion is based on surveys among scientists interviewed on TV and in newspapers, and on a content analysis of the coverage of social science in Norwegian dailies.
General practice and new genetics: what do general practitioners know about community carrier screening for cystic fibrosis?
Authors: Boulton Mary , Williamson Robert
Published: August 2002

As one of the first genetic conditions for which community carrier screening is possible, cystic fibrosis provides an opportunity to examine the way in which health professionals understand and assess issues associated with the clinical applications of the `new genetics'. This paper presents the results of a postal survey of general practitioners in the UK. Completed questionnaires were returned by 388 GPs (64%). The majority had a limited understanding of the epidemiology and population genetics of CF. Less than half (164, 44%) indicated the correct estimate of carrier frequency and only a third (144, 39%) indicated the correct likelihood of inheriting the carrier state. By contrast, the majority of GPs supported community carrier screening for CF. Almost all (339, 92%) felt the benefits of screening were important, and almost half (172, 45%) wanted to offer carrier screening in their own practices. These findings point to major gaps in GPs' understanding of genetics and raise further questions about the grounds on which their support for screening is based.
Ideology and the New Deal `fact film' Power and the Land
Authors: Kline Ronald R.
Published: August 2002

This paper examines the making of the US government documentary film, Power and the Land (1940), in terms of how views about science and technology are communicated to the public. The paper argues that the film was shaped by a complex ideology of technical progress shared by the film's maker and sponsors (the Rural Electrification Administration; the short-lived US Film Service, headed by the award-winning director, Pare Lorentz; and Joris Ivens, an internationally acclaimed Dutch director and leftist), tensions between goals of producing a `factual' and `propagandistic' film, and perceptions of the rural audiences' response. This paper thus argues against the view that science and technology communication is simply the mediated diffusion of knowledge from scientists and engineers to the public (in this case, knowledge about the social and economic aspects of rural electrification) and supports an interactive model. The paper also compares Power and the Land with the better known documentaries by Lorentz, The Plow that Broke the Plains and The River, and with other `fact films' of the New Deal era that portray a relationship between technology and social change.
The evolving museum
Authors: Endersby Jim
Published: August 2002

This paper examines a recent exhibition on evolution at the Australian Museum, in Sydney, and contrasts it with the museum's earlier exhibitions on the same theme, looking at the images of science each presents. The differences between the most recent display and its predecessors can be broadly grouped under three themes: the use of narrative and chronology to organize the display; the use of realistic dioramas and reconstructions; and the use of glass cases to keep the visitors and the science apart. Partly through deliberate decisions and partly through other pressures—including space, time and financial considerations—the newest exhibition has resolved some of the problems exemplified by the earlier ones. Nevertheless, other difficulties remain and the conclusion sketches some possible directions which museum designers might explore in the future.
Civilization and madness: the great BSE scare of 1996
Authors: Jasanoff Sheila
Published: August 2002

During the UK's BSE crisis of 1996, citizens and their public institutions experienced an unprecedented breakdown of communication that I call `civic dislocation'—a mismatch between what governmental institutions were supposed to do for the public, and what they actually did. Trust in government vanished, and people looked elsewhere for information and advice. In the UK, public confidence in governmental advisers rests on the reliability of persons rather than (primarily) the rationality of their views; in the USA, on the other hand, trust rests in formal processes and styles of reasoning that ensure the transparency and objectivity of governmental decisions. UK policy institutions require a set of conditions—among them a shared, unambiguous problem definition, relative certainty about `objective facts' and identifiable expert knowledge—which in the BSE case simply did not exist. Given the pervasive uncertainties, the distance between citizens and experts was greatly reduced, and the lay public was almost as well positioned as the experts to make sensible decisions about how to avoid the risk of BSE. This reading of civic dislocation in the UK should make us wary of recent proposals to create pockets of insulated expertise within the US risk management system to neutralize unfounded public fears through rationality, expertise, insulation and authority. A programme that values rationality and efficiency most highly leaves little room or reason for lay inputs; and, by putting too little faith in people and too much in the objectivity of formal analysis, may also carry the seeds of civic dislocation.
Dinosaurs and white elephants: the science center in the twenty-first century
Authors: Bradburne James M.
Published: August 2002

This paper argues that science centers are expensive to create as capital projects, expensive to maintain with professional staff, and, given the high costs of exhibit development, expensive to change. Lacking a fixed collection of unique artifacts with which to attract visitors, the science center is at risk when it cannot change quickly enough to meet the demands of its users. In the past, temporary exhibitions have been used as a means of creating more frequent change. Now, however, given the exponential increase of the availability of new electronic media, coupled with their massive interconnection via the Internet, informal learning can be had at home and in other sites, rendering the science center unwieldy, expensive, irrelevant, and obsolete. Threats to the science center cannot be lightly shrugged off, and a real transformation of the institution is required. The paper concludes that the science center, as an institution and as a building project, is doomed to extinction as a consequence of two factors—ecology and economy. It argues for the need to develop a new kind of institution of informal learning in its place.
Perceptions, attitudes and ethical valuations: the ambivalence of the public image of biotechnology in Spain
Authors: Luján José L. , Todt Oliver
Published: August 2002

This paper analyzes the study of the public perception of biotechnology, comparing different studies made on the European and the Spanish national levels. It aims at testing the applicability of these kinds of studies, and describes some of their limits. The analysis shows clear ambivalence in the public response to distinct applications of this technology, pointing out the crucial differences between general moral valuation and attitude towards specific products. Taking into account this difference appears fundamental for the design of future perception studies able to more accurately reflect public understanding.
On the role of energy conservation in high-energy nuclear scattering
Authors: Drescher H J , Hladik M , Ostapchenko S , Pierog T , Werner K
Published: August 2002

We argue that the most commonly used models for nuclear scattering at ultra-relativistic energies do not treat energy conservation in a consistent fashion. Demanding theoretical consistency as a minimal requirement for a realistic model, we provide a solution for the above-mentioned problem, the so-called 'parton-based Gribov-Regge theory'.

In order to keep a clean picture, we do not consider secondary interactions. We provide a very transparent extrapolation of the physics of more elementary interactions towards nucleus-nucleus scattering, without considering any nuclear effects due to final state interactions. In this sense we consider our model a realistic and consistent approach to describe the initial stage of nuclear collisions.
Why Stating Hypotheses in Grant Applications Is Unnecessary
Authors: Hernán Miguel A. , Greenland Sander
Published: January 2024

This Viewpoint argues that a hypothesis-centric approach to writing grant applications is problematic and instead suggests that funding applications should be evaluated by their relevance and methodological quality rather than by qualitative assertions before the study is conducted.
An unusual artifact observed on screening mammography in a patient with an LVAD
Authors: Nisbet Audrey I. , Ahmadian David , Vedantham Srinivasan , Chiang Jing‐Tzyh Alan
Published: January 2024

Purpose

Screening mammography and digital breast tomosynthesis consist of high‐resolution x‐ray images to identify findings that are potentially indicative of breast cancer, enabling early detection and reduction of breast cancer mortality. Imaging artifacts can occasionally occur, sometimes due to patient‐related medical devices. Because of continuous evolution of new technologies, there is potential for novel artifacts to be encountered. In this technical note, we report an unusual artifact in the screening mammogram of a patient with an Abbott HeartMate 3 left ventricular assist device (LVAD).

Methods

A 72‐year‐old patient with a HeartMate 3 LVAD presented to our breast imaging facility for a standard screening exam with digital breast tomosynthesis (Selenia Dimensions, Hologic Inc., Bedford, MA) and synthetic 2D images (C‐view, Hologic Inc., Bedford, MA).

Results

Linear artifacts oriented in the anteroposterior dimension demonstrating a spatial periodicity of ∼1.4 mm were seen on all left breast images, whereas concurrent right breast images did not demonstrate any artifacts. Repeat attempts using two identical digital breast tomosynthesis units demonstrated the same artifacts. No other exam at our imaging center that day demonstrated any such artifacts. Mammogram exams performed on this patient prior to her LVAD placement did not exhibit any similar artifacts.

Conclusion

Findings support the patient's LVAD as the underlying source of linear artifacts observed on left breast images, particularly given the proximity of the LVAD to the left breast. With the number of patients receiving LVAD placement on the rise, as well as increasing median survival rates status post LVAD implantation, recognition of this LVAD related artifact on mammography may be important.
Investigation of the Associations of Smoking With Hip Osteoarthritis: A Baseline Cross‐Sectional and Four‐ to Five‐Year Longitudinal Multicohort Study
Authors: Salis Zubeyir
Published: January 2024

Objective

This study aimed to investigate the effect of smoking on the prevalence, incidence, and progression of hip osteoarthritis (OA). We used data from the Osteoarthritis Initiative (OAI) and the Cohort Hip and Cohort Knee (CHECK) studies.

Methods

We analyzed 9,386 hips from 4,716 participants (OAI cohort) and 1,954 hips from 977 participants (CHECK cohort). The primary exposure was smoking status at baseline, categorized as current, former, or never smoker. Outcomes of radiographic hip OA (RHOA) and symptomatic hip OA were evaluated both cross‐sectionally at baseline and longitudinally over a 4‐ to 5‐year follow‐up, with adjustments for major covariates.

Results

No significant differences were observed between current or former smokers and never smokers for any of the outcomes examined, either at baseline or at the 4‐ to 5‐year follow‐up. In the cross‐sectional analysis, the odds ratios with 95% confidence intervals for the prevalence of RHOA for current and former smokers were 1.29 (0.68–2.46) and 0.99 (0.70–1.40) in the OAI cohort and 1.38 (0.78–2.44) and 0.85 (0.54–1.32) in the CHECK cohort, respectively. In the longitudinal analysis, odds ratio with 95% confidence intervals for the incidence of RHOA were 1.03 (0.23–4.50) and 0.92 (0.46–1.85) in the OAI cohort and 0.61 (0.34–1.11) and 1.00 (0.69–1.44) in the CHECK cohort, respectively.

Conclusion

Our study found no clear association between smoking and the prevalence, incidence, or progression of RHOA or symptomatic hip OA, either at baseline or over a 4‐ to 5‐year period.
Second Harmonic Generation Control in 2D Layered Materials: Status and Outlook
Authors: Huang Wenjuan , Xiao Yue , Xia Fangfang , Chen Xiangbai , Zhai Tianyou
Published: January 2024

Second harmonic generation (SHG) as an essential nonlinear optical effect, has gradually shifted its research trend toward the integration and miniaturization of photonic and optoelectronic on‐chip devices in recent years. 2D layered materials (2DLMs) open up a new research paradigm of nonlinear optics due to their large second‐order susceptibility, atomically thin structure, and perfect phase‐matching. However, 2DLMs are facing a bottleneck of weak SHG conversion efficiency limit caused by short light–matter interaction lengths at a nanoscale. Moreover, advances in integrated on‐chip SHG devices based on 2DLMs rely on the continuing development of novel strategies with tunable and efficient SHG responses. Here, this review provides a comprehensive overview of recent progress in exploring highly efficient and tunable SHG responses in 2DLMs. Various modulation and enhancement strategies for the SHG response of 2DLMs are extensively studied and systematically discussed, which can be classified into two categories: symmetry breaking and light‐matter interaction enhancement. Moreover, remaining challenges and outlooks toward further extending and realizing the practical applications of 2DLMs in nonlinear on‐chip integrated devices with SHG modulation and enhancement characteristics are discussed.
On‐Patient Temporary Medical Record for Accurate, Time‐Sensitive Information at the Point of Care
Authors: Collins Joe , Han Jooli , Sarmadi Morteza , Allison‐Logan Stephanie , Straeten Aurelien vander , Perkinson Collin F. , Acolaste Sarah , Kanelli Maria , Daristotle John , Karchin Ari , Henderson Mitchell , Cruz Mache , Artzi Dolev , Alsaiari Shahad K. , Zhang Linzixuan , Levy Lauren , Wood Lowell , Jing Lihong , McHugh Kevin J. , Bawendi Moungi G. , Langer Robert , Jaklenec Ana
Published: January 2024

Accurate medical recordkeeping is important for personal and public health. Conventional forms of on‐patient medical information, such as medical alert bracelets or finger‐markings, may compromise patient privacy because they are readily visible to other people. Here, the development of an invisible, temporary, and easily deployable on‐patient medical recordkeeping system is reported. Information is stored in unique patterns of spatially distributed near‐infrared (NIR) fluorescent quantum dots (QDs), which are delivered to the skin using dissolvable microneedle arrays. The patterns are invisible to the naked eye but detectable with an infrared camera, which can extract information with >98% accuracy using automated pattern recognition software. By encapsulating NIR QDs in an FDA‐approved biodegradable polymer, biodegradation rates can be tuned so that the encoded medical information can be conveyed in both a spatial and temporal manner, with some components fading within 100 days and others persisting for 6 months. This may be particularly useful for administering a series of vaccinations or treatments by indicating if enough time has passed for the patient to receive the next dose. Importantly, this system contains no personal information, does not require connection to a centralized database, and is not visible to the naked eye, ensuring patient privacy.
Large‐Scale Synthesis of Flexible Cermet Interdigital Electrodes with Stable Ceramic‐Metal Contact for Fire‐Resistant Pressure Tactile Sensors
Authors: Guo Yongshi , Zhang Xiaohua , Jiang Feng , Tian Xuwang , Wu Jiawei , Yan Jianhua
Published: January 2024

Cermet has broad applications in electronics, but achieving stable ceramic‐metal contact has always been a challenge, particularly at hot temperature and large deformation conditions, due to the significant differences in thermal expansion coefficient and stiffness of ceramics and metals. Here, stress matching and strong interphase bonding at the heterogenous ceramic‐metal contact are realized by using flexible ceramics, leading to stable applications in flexible fire‐resistant pressure tactile sensors. Cu/Au nanolayers are deposited first onto the toughened flexible SiO2 nanofibers with a chemical plating method to form sensitive interdigital electrode sensors, then use an in situ thermal reaction strategy to form conformal and interlocked Au3Cu and CuSiO3 interphases, which enhance the mechanical thermal stability of the ceramic‐metal contact. With deep learning technique, the as‐fabricated intelligent pressure tactile gloves can accurately recognize the human body parts in low‐visible burning environments and show a long‐term stability over 1000 cycles with a high sensitivity of 112.18 kPa−1, which is important for developing intelligent firefighting.
Controlling the Supramolecular Architecture Enables High Lithium Cationic Conductivity and High Electrochemical Stability for Solid Polymer Electrolytes
Authors: Xie Ke , Fu Qiang , Chen Fangfang , Zhu Haijin , Wang Xiaoen , Huang Gongyue , Zhan Hualin , Liang Qinghua , Doherty Cara M. , Wang Dawei , Qiao Greg G. , Li Dan
Published: January 2024

Solid polymer electrolytes (SPEs) are long sought after for versatile applications due to their low cost, light weight, flexibility, ease of scale‐up, and low interfacial impedance. However, obtaining SPEs with high Li+ conductivity (σ+) and high voltage stability to avoid concentrated polarization and premature capacity loss has proven challenging. Here a stretchable dry‐SPE is reported with a semi‐interpenetrating, supermolecular architecture consisting of a cross‐linked polyethylene oxide (PEO) tetra‐network and an alternating copolymer poly(ethylene oxide‐alt‐butylene terephthalate). Such a unique supermolecular architecture suppresses the formation of Li+/PEO intermolecular complex and enhances the oxidation stability of PEO‐based electrolyte, thus maintaining high chain segmental motion even with high salt loading (up to 50 wt%) and achieving a wide electrochemical stability window of 5.3 V. These merits enable the simultaneous accomplishment of high ionic conductivity and high Li+ transference number (t+) to enhance the energy efficiency of energy storage device, and electrochemical stability.
Constructing Ultra‐Shallow Near‐Edge States for Efficient and Stable Perovskite Solar Cells
Authors: Zhu Xueliang , Xiong Wenqi , Hu Chong , Mo Kangwei , Yang Man , Li Yanyan , Li Ruiming , Shen Chen , Liu Yong , Liu Xiaoze , Wang Sheng , Lin Qianqian , Yuan Shengjun , Liu Zhengyou , Wang Zhiping
Published: January 2024

Electronic band structure engineering of metal‐halide perovskites (MHP) lies at the core of fundamental materials research and photovoltaic applications. However, reconfiguring the band structures in MHP for optimized electronic properties remains challenging. This article reports a generic strategy for constructing near‐edge states to improve carrier properties, leading to enhanced device performances. The near‐edge states are designed around the valence band edge using theoretical prediction and constructed through tailored material engineering. These states are experimentally revealed with activation energies of around 23 milli‐electron volts by temperature‐dependent time‐resolved spectroscopy. Such small activation energies enable prolonged carrier lifetime with efficient carrier transition dynamics and low non‐radiative recombination losses, as corroborated by the millisecond lifetimes of microwave conductivity. By constructing near‐edge states in positive‐intrinsic‐negative inverted cells, a champion efficiency of 25.4% (25.0% certified) for a 0.07‐cm2 cell and 23.6% (22.7% certified) for a 1‐cm2 cell is achieved. The most stable encapsulated cell retains 90% of its initial efficiency after 1100 h of maximum power point tracking under one sun illumination (100 mW cm−2) at 65 °C in ambient air.
Versatile Nitrogen‐Centered Organic Redox‐Active Materials for Alkali Metal‐Ion Batteries
Authors: Dong Huanhuan , Kang Ning , Li Lin , Li Li , Yu Yan , Chou Shulei
Published: January 2024

Versatile nitrogen‐centered organic redox‐active molecules have gained significant attention in alkali metal‐ion batteries (AMIBs) due to their low cost, low toxicity, and ease of preparation. Specially, their multiple reaction categories (anion/cation insertion types of reaction) and higher operating voltage, when compared to traditional conjugated carbonyl materials, underscore their promising prospects. However, the high solubility of nitrogen‐centered redox active materials in organic electrolyte and their low electronic conductivity contribute to inferior cycling performance, sluggish reaction kinetics, and limited rate capability. This review provides a detailed overview of nitrogen‐centered redox‐active materials, encompassing their redox chemistry, solutions to overcome shortcomings, characterization of charge storage mechanisms, and recent progress. Additionally, prospects and directions are proposed for future investigations. It is anticipated that this review will stimulate further exploration of underlying mechanisms and interface chemistry through in situ characterization techniques, thereby promoting the practical application of nitrogen‐centered redox‐active materials in AMIBs.
Hexamethyldisilazane‐Mediated Synthesis of N‐Formamides, Benzimidazoles and Quinazolinones Using N,N‐Dimethylformamide as a C1 Source
Authors: Lin Wei‐Han , Liang Chien‐Fu
Published: January 2024

This paper presents a amidinyl transfer reagent for the synthesis of nitrogen‐containing compounds, wherein N,N‐dimethylformamide is used as the C1 source to react with hexamethyldisilazane, generating the N,N‐dimethylformimidamide intermediate. This intermediate is then reacted with amines to induce amidinyl transfer. This protocol can be applied for the synthesis of N‐formamide, benzimidazole and quinazolinone, for which amine derivatives used as substrates under optimized conditions. The advantages of this method are its operational simplicity, high efficiency, structural diversity in products with favorable yields, and applicability in gram‐scale operations.
Light‐Driven Synthesis and Functionalization of Bicycloalkanes, Cubanes and Related Bioisosteres
Authors: Cuadros Sara , Paut Julien , Anselmi Elsa , Dagousset Guillaume , Magnier Emmanuel , Dell'Amico Luca
Published: January 2024

Bicycloalkanes, cubanes and their structural analogues have emerged as bioisosteres of (hetero)arenes. To meet increasing demand, the chemical community has developed a plethora of novel synthetic methods. In this review, we assess the progress made in the field of light‐driven construction and functionalization of such relevant molecules. We have focused on diverse structural targets, as well as on reaction processes giving access to: (i) [1.1.1]‐bicyclopentanes (BCPs); (ii) [2.2.1]‐bicyclohexanes (BCHs); (iii) [3.1.1]‐bicycloheptanes (BCHeps); and (iv) cubanes; as well as other structurally related scaffolds. Finally, future perspectives dealing with the identification of novel reaction manifolds to access new functionalized bioisosteric units are discussed.
Bayesian analysis of Markov modulated queues with abandonment
Authors: Ay Atilla , Landon Joshua , Özekici Süleyman , Soyer Refik
Published: January 2024

We consider a Markovian queueing model with abandonment where customer arrival, service and abandonment processes are all modulated by an external environmental process. The environmental process depicts all factors that affect the exponential arrival, service, and abandonment rates. Moreover, the environmental process is a hidden Markov process whose true state is not observable. Instead, our observations consist only of customer arrival, service, and departure times during some period of time. The main objective is to conduct Bayesian analysis in order to infer the parameters of the stochastic system, as well as some important queueing performance measures. This also includes the unknown dimension of the environmental process. We illustrate the implementation of our model and the Bayesian approach by using simulated and actual data on call centers.
Reactor development for a one‐step hybrid catalytic conversion of D‐glucose to HMF
Authors: Gimbernat Alexandra , Heuson Egon , Dumeignil Franck , Delcroix Damien , Girardon Jean‐Sébastien , Froidevaux Rénato
Published: January 2024

The design of an “H”‐shaped reactor has been studied to satisfy the possibility of using a triphasic medium to transform d‐glucose into 5‐hydroxymethylfurfural (HMF) by a hybrid catalytic process using an immobilized glucose isomerase, allowing the isomerization of D‐glucose to d‐fructose, and a heterogeneous chemical catalyst to catalyze the dehydration of d‐fructose to HMF. The various parameters influencing the transport of d‐fructose within the reactor were studied, namely the difference in pH between the two aqueous phases, the agitation and the quantity of 3,4‐DCPBA/Aliquat336® used to extract and transport continuously the d‐fructose. The pH discrepancy, which must be between 5.0 and 5.5, turns out to be the real driving force behind the extraction of D‐fructose. The D‐Fru/3,4‐DCPBA molar ratio of 1/0.25 allowed the transport of more than 80 % of the D‐fructose initially present and shows that the same molecule of 3,4‐DCPBA is involved at least twice in the transport of D‐fructose and that the 3,4‐DCPBA/Aliquat336® couple performs a turnover within the organic phase. Finally, a HMF production yield of 30.9 % and an isomerization yield of 79.1 % were obtained, illustrating the shift in the isomerization equilibrium made possible by a D‐fructose extraction yield of 96.8 %.
Breaking the Symmetry of Nitrogen‐Coordinated Single‐Atom Catalysts for Advanced Peroxymonosulfate Oxidation
Authors: Li Xue , Long Mingce , Zhang Lizhi
Published: January 2024

Tuning the electronic distribution of the single‐atom sites in single‐atom catalysts (SACs) is crucial for unlocking their catalytic potential. The four‐nitrogen‐coordinated transitional metal (M−N4) configuration has been widely investigated in peroxymonosulfate (PMS)‐based advanced oxidation processes (PMS‐AOPs), but restricted by the sluggish electron transfer from PMS to generate the high‐valent metal‐oxo (HVMO), reactive species with high redox potentials and long half‐lives, for the degradation of organic pollutants in water due to its symmetric structure. Recently, the SACs with asymmetric coordination configurations are found to break the symmetric electronic distribution of M−N4, which facilitates the O−H and O−O bond breaking in PMS, thus promoting HVMO formation. Asymmetric coordination has emerged as a novel and effective strategy for single‐atom coordination modulation. In this paper, two strategies for breaking the symmetry of nitrogen‐coordinated SACs by planar heteroatom doping and axial optimization engineering are outlined, and the reaction mechanisms on the formation of HVMO species over asymmetrically coordinated SACs via PMS activation are highlighted. Finally, we prospect the development of asymmetrically coordinated SACs in water purification.
Long cycle‐life aqueous Zn battery enabled by facile carbon nanotube coating on Cu current collector
Authors: Cho Beom‐Keun , Huh Sung‐Ho , Kim So Hee , Yu Seungho , Bae Jong‐Seong , Yoo Jung‐Keun , Yu Seung‐Ho
Published: January 2024

As an alternative to Li‐ion batteries, aqueous Zn batteries have gained attention due to the abundance of Zn metal, low reduction potential (–0.76 V vs. standard hydrogen electrode), and high theoretical capacity (820 mAh g–1) of multivalent Zn2+ ion. However, the growth of Zn dendrites and the formation of irreversible surface reaction byproducts pose challenges for ensuring a long battery lifespan and commercialization. Herein, the Cu foil coated with a single‐walled carbon nanotube (SWCNT) layer using a facile doctor blade casting method is utilized. The SWCNT‐coated Cu foil demonstrates a significantly longer battery lifespan compared to the bare Cu in the half‐cell tests. Through operando optical microscopy imaging, we are able to provide intuitive evidence that Zn deposition occurs between the carbon nanotube (CNT) coating and Cu substrate, in agreement with the computational results. Also, with various imaging techniques, the flat morphology and homogeneous distribution of Zn beneath the SWCNT layer are demonstrated. In addition, the full‐cell using CNT‐coated Cu exhibits a long cycle life compared to the control group, thereby demonstrating improved electrochemical performance with limited Zn for the cycling process.
Charge‐Assisted Ionic Hydrogen‐Bonded Organic Frameworks: Designable and Stabilized Multifunctional Materials
Authors: Chen Xu‐Yong , Cao Li‐Hui , Bai Xiang‐Tian , Cao Xiao‐Jie
Published: January 2024

Hydrogen‐bonded organic frameworks (HOFs) are a class of crystalline framework materials assembled by hydrogen bonds. HOFs have the advantages of high crystallinity, mild reaction conditions, good solution processability, and reproducibility. Coupled with the reversibility and flexibility of hydrogen bonds, HOFs can be assembled into a wide diversity of crystalline structures. Since the bonding energy of hydrogen bonds is lower than that of ligand and covalent bonds, the framework of HOFs is prone to collapse after desolventisation and the stability is not high, which limits the development and application of HOFs. In recent years, numerous stable and functional HOFs have been developed by π–π stacking, highly interpenetrated networks, charge‐assisted, ligand‐bond‐assisted, molecular weaving, and covalent cross‐linking. Charge‐assisted ionic HOFs introduce electrostatic attraction into HOFs to improve stability while enriching structural diversity and functionality. In this paper, we review the development, the principles of rational design and assembly of charge‐assisted ionic HOFs, and introduces the different building block construction modes of charge‐assisted ionic HOFs. Highlight the applications of charge‐assisted ionic HOFs in gas adsorption and separation, proton conduction, biological applications, etc., and prospects for the diverse design of charge‐assisted ionic HOFs structures and multifunctional applications.
Fine‐needle aspiration of amyloidoma: A critical analysis
Authors: Ramani Nisha S. , Krishnan Bhuvaneswari
Published: January 2024

Background

Amyloid, presenting as a mass, is termed amyloidoma. Among the reported cases, fine‐needle aspiration (FNA) of amyloid is often misinterpreted as acellular nondiagnostic material.

Methods

A computer search of all FNAs was performed and cases diagnosed as amyloidoma were identified.

Results

Among 11,956 cases and 20,634 FNAs, there were six cases and 12 FNAs of amyloidoma. One case with mucin/myxoid matrix was misinterpreted as amyloid, which on our review was Congo red negative. All five other cases of amyloidoma were adequate for evaluation. The smears showed most of the aspirated contents in the middle of the slide and it did not spread when smeared. The amyloid was present as large chunks of waxy, smooth, orangophilic/cyanophilic fragments on Papanicolaou stain and as basophilic fragments on Diff‐Quik stain in a clean background. In cases with lymphoma/myeloma, there were admixed lymphocytes and/or plasma cells. Unlike fibrous tissue, amyloid aspirates well and provides adequate material for interpretation. The clean background distinguishes it from mucin/myxoid matrix. Congo red stain was positive with apple green birefringence in all five cases. Further subtyping by mass spectrometry showed AL (κ) type in three patients and AIns (insulin) type in one patient. In one patient with lymphoma, the subtyping was not done.

Conclusion

FNA of amyloidoma is rare (0.04%), but an optimal method for diagnosis and subtyping, avoiding unwanted surgical interventions. Although mistaken for fibrous tissue, which aspirates poorly, abundant acellular orangophilic/cyanophilic material on FNA should raise a suspicion for amyloid. Unlike mucin/myxoid matrix, amyloid does not smear the background.