bluuebunny/crossref_metadata_2025 huggingface dataset:
Cells in Slow Motion: Apparent Undercooling Increases Glassy Behavior at Physiological Temperatures
Authors: Schnauß Jörg , Kunschmann Tom , Grosser Steffen , Mollenkopf Paul , Zech Tobias , Freitag Jessica S. , Prascevic Dusan , Stange Roland , Röttger Luisa S. , Rönicke Susanne , Smith David M. , Bayerl Thomas M. , Käs Josef A.
Published: June 2021

Solvent conditions are unexpectedly sufficient to drastically and reversibly slow down cells. In vitro on the molecular level, protein–solvent interactions drastically change in the presence of heavy water (D2O) and its stronger hydrogen bonds. Adding D2O to the cell medium of living cells increases the molecular intracellular viscosity. While cell morphology and phenotype remain unchanged, cellular dynamics transform into slow motion in a changeable manner. This is exemplified in the slowdown of cell proliferation and migration, which is caused by a reversible gelation of the cytoplasm. In analogy to the time–temperature superposition principle, where temperature is replaced by D2O, an increase in viscosity slows down the effective time. Actin networks, crucial structures in the cytoplasm, switch from a power‐law‐like viscoelastic to a more rubber‐like elastic behavior. The resulting intracellular resistance and dissipation impair cell movement. Since cells are highly adaptive non‐equilibrium systems, they usually respond irreversibly from a thermodynamic perspective. D2O induced changes, however, are fully reversible and their effects are independent of signaling as well as expression. The stronger hydrogen bonds lead to glass‐like, drawn‐out intramolecular dynamics, which may facilitate longer storage times of biological matter, for instance, during transport of organ transplants.
Multilevel Photonic Transistor Memory Devices Based on 1D Electrospun Semiconducting Polymer /Perovskite Composite Nanofibers
Authors: Ercan Ender , Lin Yan‐Cheng , Hsu Li‐Che , Chen Chun‐Kai , Chen Wen‐Chang
Published: June 2021

Photonic field‐effect transistor (FET) memory devices offer unique advantages over conventional voltage‐driven memory devices, such as noncontact programming capability, rapid data transmission, and low power consumption. In this article, the first example of a nanofiber‐only photonic FET memory device is reported. Perovskite nanocrystal (βNC)‐embedded polythiophenes are employed as 1D semiconducting channels of the nanofiber matrix. A decent On/Off current ratio of ≈103 is reached for the best device with a prolonged data retention of over 104 s, attributing to the favorable energy level alignment and molecular packing of conjugated polymers in nanofibers. The composite nanofiber system exhibits superior photoresponsivity and charge retention, outperforming its film‐based counterpart owing to its regular 1D confined structure, and well‐dispersed βNCs. Collectively, the structurally fine‐tuned conjugated polymer and the 1D confined structure in the nanofiber promise good data discriminability and a highly fault‐tolerant photonic memory device. In addition, the fiber‐based flexible memory device exhibits excellent photonic memory performance, indicating its integrity for application in wearable electronics. The current system represents the first application of 1D perovskite nanocrystal/conjugated polymer composite nanofibers for high‐performance photonic memory devices, which reveals their potential to make composite nanostructures for novel pioneering photonic applications.
Naphthalene Flanked Diketopyrrolopyrrole: A New Functional Dye Based Optical Sensors for Monitoring Cyanide Ions in Water
Authors: Gholami Mahnaz D. , Liu Qian , Sonar Prashant , Manzhos Sergei , Ayoko Godwin A. , Izake Emad L.
Published: June 2021

Cyanide (CN−) is one of the most hazardous ions to humans and the environment. Therefore, sensitive, and selective sensors for CN− monitoring are highly required. A novel chemosensor based on naphthalene flanked diketopyrrolopyrrole dye (TBC‐DPPN) is synthesized for the direct detection of CN− in water samples by naked eye and vibrational spectroscopy (UV–Vis and fluorescence). The electron deficient carbonyl group of the lactam ring of TBC‐DPPN undergoes a nucleophilic attack by the CN− thus causing the yellow color of the dye turn to colorless, and fluorescence of the dye at 527 nm to turn‐off. The mechanism of CN− sensing by the TBC‐DPPN sensor is confirmed by spectral measurements and density functional theory (DFT) calculations. The TBC‐DPPN sensor is utilized to determine the CN− by colorimetric and fluorescence methods in water down to 0.5 and 0.05 µm, respectively, which is well below the cut off limit of 1.9 µm that is recommended by the World Health Organization (WHO). Therefore, TBC‐DPPN can act as dual channel sensor with high selectivity and sensitivity for the determination of CN− in water.
One‐Step Formation of Hybrid Nanocrystal Gels: Deposition of Metal Domains on CdSe/CdS Nanorod and Nanoplatelet Networks
Authors: Zámbó Dániel , Schlosser Anja , Graf Rebecca T. , Rusch Pascal , Kißling Patrick A. , Feldhoff Armin , Bigall Nadja C.
Published: June 2021

Hybrid semiconductor‐based nanocrystals (NCs) are generally synthesized in organic media prior to their assembly into catalytically promising nanostructures via multistep methods. Here, a tunable, easy‐to‐adapt and versatile approach for the preparation of hybrid nanoparticle networks from aqueous nanocrystal solutions is demonstrated. The networks consist of interconnected semiconductor NC backbones (made of CdSe/CdS dot‐in‐rods or core/crown nanoplatelets) decorated with noble metal (Au and Pt) or with metal‐based domains (Co2+ and Ni2+) demonstrating a powerful synthetic control over a variety of hybrid nanostructures. The deposition of the domains and the formation of the network take place simultaneously (one‐step method) at room temperature in dark conditions without any external trigger. Beside the in‐depth structural characterization of the gel‐like hybrid networks, the wavelength‐dependent optical features are studied to reveal an efficient charge carrier separation in the systems and a controllable extent of fluorescence quenching through the domain sizes. Photoluminescence quantum yields and decay dynamics highlight the importance of fine‐tuning the conduction band/Fermi level offset between the semiconductors and the various deposited metals playing central role in the electron–hole separation processes. This procedure provides a novel platform toward the preparation of photo(electro)catalytically promising hybrid nanostructures (acetogels and xerogels) without the need of presynthetic hybrid particle design.
Air‐Stable Silicon Nanocrystal‐Based Photon Upconversion
Authors: Xia Pan , Schwan Joseph , Dugger Thomas W. , Mangolini Lorenzo , Tang Ming Lee
Published: June 2021

Photon upconversion may have the highest impact in biological applications because incoming photons transparent to tissue can be combined to make visible light useful for photodynamic therapy and imaging. The ability to use semiconductor nanocrystals as light absorbers for photon upconversion is important because their strong absorption profiles are synthetically tunable. In particular, the use of earth‐abundant, environmentally benign silicon quantum dots (QDs) as light absorbers for photon upconversion is very attractive. In this work, the authors demonstrate a general strategy employing both physical and chemical barriers to achieve air‐stable fusion of triplet excitons photosensitized by silicon QDs, crucial to practical applications of photon upconversion. Gel permeation chromatography (GPC) and dynamic light scattering (DLS) show that thermal hydrosilylation critical for colloidal stability and efficient triplet energy transfer creates a polymeric barrier to oxygen. This kinetic barrier to oxygen arises from the presence of cross‐linked surfactants and is complemented by the sacrificial oxidation of silicon QDs itself. Photon upconversion lasted longer than 4 days with quantum yields (QYs) as high as 7.5% (out of a maximum of 50%) using Si QD light absorbers with diphenylanthracene in methyl oleate. Oil‐in‐water micelles are air‐stable for 2 days with absolute upconversion QYs of 5.5%.
High‐Density Organic Electro‐Optic Crystals for Ultra‐Broadband THz Spectroscopy
Authors: Seok Jin‐Hong , Puc Uros , Kim Seung‐Jun , Yoon Woojin , Yun Hoseop , Yu In Cheol , Rotermund Fabian , Kim Dongwook , Jazbinsek Mojca , Kwon O‐Pil
Published: June 2021

Ultra‐broadband THz photonics covering the 0.3–20 THz range provides a very attractive foundation for a wide range of basic research and industrial applications. However, the lack of ultra‐broadband THz devices has yet to be overcome. In this work, high‐density organic electro‐optic crystals are newly developed for efficient THz wave generation in a very broad THz spectral range and are successfully used for a broadband THz time‐domain spectroscopy. The new organic THz generator crystals, namely the OHP‐TFS crystals, have very low void volume, high density, and are shown to cover the ultra‐broadband THz spectrum up to about 15 THz, which cannot be easily accessed with the more widely used inorganic‐based THz generators. In addition to the very favorable broadband properties, the generated THz electric‐field amplitude at the pump wavelength of 1560 nm is about 40 times higher than that generated by a commercial inorganic THz generator (ZnTe crystal). By using the newly developed OHP‐TFS as generation crystal in a compact table‐top all‐organic THz time‐domain spectrometer based on a low‐cost telecom fiber laser, the optical characteristics of a model material are successfully determined in the broad 1.5–12.5 THz range with high accuracy.
Superb Nonlinear Absorption of Triphenylene‐Based Metal–Organic Frameworks Associated with Abundant Metal d Electrons
Authors: Sun Yanhui , Li Hui , Gao Xiangyun , Yu Zhiyang , Huang Zhipeng , Zhang Chi
Published: June 2021

The exploitation of high‐performance nonlinear optical (NLO) materials is necessitated by the broad application of ultra‐intensive and ultra‐fast lasers. The superb nonlinear absorption and electronic‐structure‐related NLO response of M3HHTP2 are introduced here, where M is Co(II), Ni(II), or Cu(II) and HHTP is 2,3,6,7,10,11‐hexahydroxytriphenylene. With the laser excitation at 532 nm, the Cu3HHTP2 exhibits a two‐photon absorption (2PA) cross‐section of 1.38 ± 0.11 × 107 GM, a value much larger than those of most reported NLO materials so far. The NLO response of M3HHTP2 correlates strongly with the number of metal d electrons. With metal d electrons number increasing from 7 to 10, the optical nonlinearity of M3HHTP2 under the laser excitation at 532 nm varies from three‐photon absorption (3PA) in Co3HHTP2, a combination of 3PA and 2PA in Ni3HHTP2, to 2PA in Cu3HHTP2. Abundant metal d electrons can mitigate the ground‐state depletion, and therefore the 2PA is enhanced. Accordingly, the superb nonlinear absorption of Cu3HHTP2 can be associated with abundant d electrons in Cu.
Potassium Base‐Catalyzed Michael Additions of Allylic Alcohols to α,β‐Unsaturated Amides: Scope and Mechanistic Insights
Authors: Sai Masahiro , Kurouchi Hiroaki
Published: June 2021

We report herein the first KHMDS‐catalyzed Michael additions of allylic alcohols to α,β‐unsaturated amides through allylic isomerization. The reaction proceeds smoothly in the presence of only 5 mol% of KHMDS to afford a variety of 1,5‐ketoamides in high yields. Mechanistic investigations, including experimental and computational studies, reveal that the KHMDS‐catalyzed in‐situ generation of the enolate from the allylic alcohol through a tunneling‐assisted 1,2‐hydride shift is the key to the success of this transformation.

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Electrochemical‐In‐Situ‐Oxidative Sulfonylation of Phenols with Sulfinic Acids as an Access to Sulfonylated Hydroquinones
Authors: Sun Xue , Zhang Fanjun , Yan Kelu , Feng Wenfeng , Sun Xuejun , Yang Jianjing , Wen Jiangwei
Published: June 2021

The electrochemical in‐situ oxidative sulfonylation of phenols with sulfinic acids access to sulfonylated hydroquinones has been developed. A series of sulfonylated hydroquinones were prepared under mild mediator‐, catalyst‐ and exogenous‐oxidant‐free conditions. Notably, such an electrochemical in‐situ‐oxidative synthetic strategy presented wide functional group tolerance and amenability to gram‐scale synthesis with 62–80% yields.

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Transforming Cotton Gin Trash to Engineered Functional Carbon Structures
Authors: Deshan Athukoralalage Don K. , Moghaddam Lalehvash , Siriwardena Dumindu P. , Strounina Ekaterina , Beltramini Jorge , Doherty William O. S.
Published: June 2021

This paper investigates the carbonization of cotton gin trash (CGT) into carbon structures shaped under the influence of different operating conditions including the impact of endogenous fatty acids impurities present in CGT. As expected, both KOH activation and high carbonization temperature increase the material surface area and porosity. Furan and arene groups are formed from 400 °C to 800 °C but the proportion of the furan groups are highest at 600 °C. This is due to the conversion of the fatty acids in CGT to furan units. XRD data reveals the presence of three aromatic layers at 400 °C, followed by structural rearrangement to the formation of five stacks aromatic layers at 800 °C consisting mainly of protonated and non‐protonated condensed arene groups. Interestingly, a reduction in the number of aromatic structures is observed if no acid pretreatment of CGT to remove inorganic impurities is conducted prior to pyrolysis to 600 °C. Two potential applications of the synthesised carbons are shown; one for the formation of 5‐hydroxymethylfurfural (80%) from fructose, which compares favorably to other porous carbon materials produced under harsher conditions, and another derived CGT carbon material which shows a good uptake of hydrogen for storage.
Safety and Immunogenicity of a Recombinant Tetanus Vaccine in Healthy Adults in China: A Randomized, Double‐Blind, Dose Escalation, Placebo‐ and Positive‐Controlled, Phase 1/2 Trial
Authors: Xu Xiaowei , Yu Rui , Xiao Lanlan , Wang Jie , Yu Meihong , Xu Junjie , Tan Yajun , Ma Xiao , Wu Xiaoxin , Lian Jiangshan , Huang Kaizhou , Ouyang Xiaoxi , Bi Sheng , Wu Shipo , Wang Xiaoyan , Jin Jiandi , Yu Ling , Zhang Huafen , Wei Qi , Shi Jinfa , Chen Wei , Li Lanjuan
Published: June 2021

Tetanus is a fatal but vaccine‐preventable disease. The currently available tetanus vaccines are tetanus toxoid (TT)‐based. Although these vaccines are generally effective, challenges in vaccine development and access remain. A randomized, double‐blind, dose escalation, placebo‐ and positive‐controlled, phase 1/2 trial (ChiCTR1800015865) is performed to evaluate the safety and immunogenicity of an alternative recombinant tetanus vaccine based on the Hc domain of tetanus neurotoxin (TeNT‐Hc) in healthy adult volunteers. The primary outcome is the safety profile of the recombinant tetanus vaccine, and immunogenicity is the secondary outcome. 150 eligible participants were enrolled and randomly assigned to receive one of the three doses of recombinant tetanus vaccine (TeNT‐Hc 10/20/30 µg), TT vaccine, or placebo. The recombinant tetanus vaccine shows a good safety profile. The frequency of any solicited and unsolicited adverse events after each vaccination does not differ across the vaccine and placebo recipients. No serious treatment‐related adverse events occur. The recombinant tetanus vaccine shows strong immune responses (seroconversion rates, geometric mean titer, and antigen‐specific CD4+/CD8+ T‐cell responses), which are roughly comparable to those of the TT vaccine. In conclusion, the findings from this study support that recombinant tetanus vaccine is safe and immunogenic; thereby, it represents a novel vaccine candidate against tetanus.
Bioinspired Biomaterial Composite for All‐Water‐Based High‐Performance Adhesives
Authors: Lo Presti Marco , Rizzo Giorgio , Farinola Gianluca M. , Omenetto Fiorenzo G.
Published: June 2021

The exceptional underwater adhesive properties displayed by aquatic organisms, such as mussels (Mytilus spp.) and barnacles (Cirripedia spp.) have long inspired new approaches to adhesives with a superior performance both in wet and dry environments. Herein, a bioinspired adhesive composite that combines both adhesion mechanisms of mussels and barnacles through a blend of silk, polydopamine, and Fe3+ ions in an entirely organic, nontoxic water‐based formulation is presented. This approach seeks to recapitulate the two distinct mechanisms that underpin the adhesion properties of the Mytilus and Cirripedia, with the former secreting sticky proteinaceous filaments called byssus while the latter produces a strong proteic cement to ensure anchoring. The composite shows remarkable adhesive properties both in dry and wet conditions, favorably comparing to synthetic commercial glues and other adhesives based on natural polymers, with performance comparable to the best underwater adhesives with the additional advantage of having an entirely biological composition that requires no synthetic procedures or processing.
A Lubricated Nonimmunogenic Neural Probe for Acute Insertion Trauma Minimization and Long‐Term Signal Recording
Authors: Lee Yeontaek , Shin Hyogeun , Lee Dongwon , Choi Sungah , Cho Il‐Joo , Seo Jungmok
Published: June 2021

Brain‐machine interfaces (BMIs) that link the brain to a machine are promising for the treatment of neurological disorders through the bi‐directional translation of neural information over extended periods. However, the longevity of such implanted devices remains limited by the deterioration of their signal sensitivity over time due to acute inflammation from insertion trauma and chronic inflammation caused by the foreign body reaction. To address this challenge, a lubricated surface is fabricated to minimize friction during insertion and avoid immunogenicity during neural signal recording. Reduced friction force leads to 86% less impulse on the brain tissue, and thus immediately increases the number of measured signal electrodes by 102% upon insertion. Furthermore, the signal measurable period increases from 8 to 16 weeks due to the prevention of gliosis. By significantly reducing insertion damage and the foreign body reaction, the lubricated immune‐stealthy probe surface (LIPS) can maximize the longevity of implantable BMIs.
Decreased Abundance of Akkermansia muciniphila Leads to the Impairment of Insulin Secretion and Glucose Homeostasis in Lean Type 2 Diabetes
Authors: Zhang Jing , Ni Yueqiong , Qian Lingling , Fang Qichen , Zheng Tingting , Zhang Mingliang , Gao Qiongmei , Zhang Ying , Ni Jiacheng , Hou Xuhong , Bao Yuqian , Kovatcheva‐Datchary Petia , Xu Aimin , Li Huating , Panagiotou Gianni , Jia Weiping
Published: June 2021

Although obesity occurs in most of the patients with type 2 diabetes (T2D), a fraction of patients with T2D are underweight or have normal weight. Several studies have linked the gut microbiome to obesity and T2D, but the role of gut microbiota in lean individuals with T2D having unique clinical characteristics remains unclear. A metagenomic and targeted metabolomic analysis is conducted in 182 lean and abdominally obese individuals with and without newly diagnosed T2D. The abundance of Akkermansia muciniphila (A. muciniphila) significantly decreases in lean individuals with T2D than without T2D, but not in the comparison of obese individuals with and without T2D. Its abundance correlates inversely with serum 3β‐chenodeoxycholic acid (βCDCA) levels and positively with insulin secretion and fibroblast growth factor 15/19 (FGF15/19) concentrations. The supplementation with A. muciniphila is sufficient to protect mice against high sucrose‐induced impairment of glucose intolerance by decreasing βCDCA and increasing insulin secretion and FGF15/19. Furthermore, βCDCA inhibits insulin secretion and FGF15/19 expression. These findings suggest that decreased abundance of A. muciniphila is linked to the impairment of insulin secretion and glucose homeostasis in lean T2D, paving the way for new therapeutic options for the prevention or treatment of diabetes.
Robust Electrodes for Flexible Energy Storage Devices Based on Bimetallic Encapsulated Core–Multishell Structures
Authors: Li Yan‐Fei , Ye Shuyang , Shi Yan‐Hong , Lin Jian , Song Yi‐Han , Su Yang , Wu Xing‐Long , Zhang Jing‐Ping , Xie Hai‐Ming , Su Zhong‐Min , Sun Hai‐Zhu , Seferos Dwight S.
Published: June 2021

Developing flexible electrodes with high active materials loading and excellent mechanical stability is of importance to flexible electronics, yet remains challenging. Herein, robust flexible electrodes with an encapsulated core‐multishell structure are developed via a spraying‐hydrothermal process. The multilayer electrode possesses an architecture of substrate/reduced graphene oxide (rGO)/bimetallic complex/rGO/bimetallic complex/rGO from the inside to the outside, where the cellulosic fibers serve as the substrate, namely, the core; and the multiple layers of rGO and bimetallic complex, are used as active materials, namely, the shells. The inner two rGO interlayers function as the cement that chemically bind to two adjacent layers, while the two outer rGO layers encapsulate the inside structure effectively protecting the electrode from materials detachment or electrolyte corrosion. The electrodes with a unique core‐multishell structure exhibit excellent cycle stability and exceptional temperature tolerance (−25 to 40 °C) for lithium and sodium storage. A combination of experimental and theoretical investigations are carried out to gain insights into the synergetic effects of cobalt‐molybdenum‐sulfide (CMS) materials (the bimetallic complex), which will provide guidance for future exploration of bimetallic sulfides. This strategy is further demonstrated in other substrates, showing general applicability and great potential in the development of flexible energy storage devices.
Spider‐Inspired Electrohydraulic Actuators for Fast, Soft‐Actuated Joints
Authors: Kellaris Nicholas , Rothemund Philipp , Zeng Yi , Mitchell Shane K. , Smith Garrett M. , Jayaram Kaushik , Keplinger Christoph
Published: June 2021

The impressive locomotion and manipulation capabilities of spiders have led to a host of bioinspired robotic designs aiming to reproduce their functionalities; however, current actuation mechanisms are deficient in either speed, force output, displacement, or efficiency. Here—using inspiration from the hydraulic mechanism used in spider legs—soft‐actuated joints are developed that use electrostatic forces to locally pressurize a hydraulic fluid, and cause flexion of a segmented structure. The result is a lightweight, low‐profile articulating mechanism capable of fast operation, high forces, and large displacement; these devices are termed spider‐inspired electrohydraulic soft‐actuated (SES) joints. SES joints with rotation angles up to 70°, blocked torques up to 70 mN m, and specific torques up to 21 N m kg−1 are demonstrated. SES joints demonstrate high speed operation, with measured roll‐off frequencies up to 24 Hz and specific power as high as 230 W kg−1—similar to human muscle. The versatility of these devices is illustrated by combining SES joints to create a bidirectional joint, an artificial limb with independently addressable joints, and a compliant gripper. The lightweight, low‐profile design, and high performance of these devices, makes them well‐suited toward the development of articulating robotic systems that can rapidly maneuver.
Facile Fabrication of Multivalent VOx/Graphene Nanocomposite Electrodes for High‐Energy‐Density Symmetric Supercapacitors
Authors: Huang Ailun , El‐Kady Maher F. , Chang Xueying , Anderson Mackenzie , Lin Cheng‐Wei , Turner Christopher L. , Kaner Richard B.
Published: June 2021

Supercapacitors have emerged as one of the leading energy‐storage technologies due to their short charge/discharge time and exceptional cycling stability; however, the state‐of‐the‐art energy density is relatively low. Hybrid electrodes based on transition metal oxides and carbon‐based materials are considered to be promising candidates to overcome this limitation. Herein, a rational design of graphene/VOx electrodes is proposed that incorporates vanadium oxides with multiple oxidation states onto highly conductive graphene scaffolds synthesized via a facile laser‐scribing process. The graphene/VOx electrodes exhibit a large potential window with a high three‐electrode specific capacitance of 1110 F g–1. The aqueous graphene/VOx symmetric supercapacitors (SSCs) can reach a high energy density of 54 Wh kg–1 with virtually no capacitance loss after 20 000 cycles. Moreover, the flexible quasi‐solid‐state graphene/VOx SSCs can reach a very high energy density of 72 Wh kg–1, or 7.7 mWh cm–3, outperforming many commercial devices. With Rct < 0.02 Ω and Coulombic efficiency close to 100%, these gel graphene/VOx SSCs can retain 92% of their capacitance after 20 000 cycles. The process enables the direct fabrication of redox‐active electrodes that can be integrated with essentially any substrate including silicon wafers and flexible substrates, showing great promise for next‐generation large‐area flexible displays and wearable electronic devices.
The pandemic of workplace violence: the gendered experience of emergency medicine trainees
Authors: Snavely Cheyenne , Romeo Michelle , Ciardiello Amber , Mojica Michael
Published: June 2021

Objectives

Many health care providers experience physical and verbal abuse from patients and their visitors. This abuse is a form of workplace violence and likely has negative implications for the providers well‐being. The objective of our study was to determine the rates of nonphysical workplace violence against emergency medicine (EM) trainees with a focus on prevalence by provider gender.

Methods

This was a single‐center prospective cohort study using tally counters to track occurrences of nonphysical workplace violence perpetrated by patients and their visitors against EM trainees in the adult emergency department.

Results

There were a total of 39 completed responses submitted by 22 respondents. Of the 22 respondents, 14 identified as women and eight identified as men. On average, both men and women experienced near daily occurrences of nonphysical workplace violence. However, women experienced higher rates compared to their colleagues who are men with a mean of three occurrences per day versus 0.9, respectively.

Conclusion

We found that women trainees were more likely to experience nonphysical workplace violence from patients and their visitors.
Virtual multispecialty point‐of‐care ultrasound rotation for fourth‐year medical students during COVID‐19: Innovative teaching techniques improve ultrasound knowledge and image interpretation
Authors: Zavitz Joshua , Sarwal Aarti , Schoeneck Jacob , Glass Casey , Hays Brandon , Shen E. , Bryant Casey , Gupta Karisma
Published: June 2021

Objectives

Point‐of‐care ultrasound (PoCUS) has been integrated into undergraduate medical education. The COVID‐19 pandemic forced medical schools to evolve clinical rotations to minimize interruption through implementation of novel remote learning courses. To address the students’ need for remote clinical education, we created a virtual PoCUS course for our fourth‐year class. We present details of the course's development, implementation, quality improvement processes, achievements, and limitations.

Methods

A virtual PoCUS course was created for 141 fourth‐year medical students. The learning objectives included ultrasound physics, performing and interpreting ultrasound applications, and incorporating PoCUS into clinical decisions and procedural guidance. Students completed a 30‐question pre‐ and posttest focused on ultrasound and knowledge of clinical concepts. PoCUS educators from 10 different specialties delivered the course over 10 days using video‐conferencing software. Students watched live scanning demonstrations and practiced ultrasound probe maneuvers using a cellular telephone to simulate ultrasound probe. Students completed daily course evaluations that were used as a continuous needs assessment to make improvements.

Results

A total of 141 students participated in the course; all received a passing grade. The mean pre‐ and posttest scores improved from 58% to 88% (p < 0.001) through the course duration. Daily evaluations revealed the percentage of students who rated the course's live scanning sessions and didactic components as “very well” increased from 32.7% on day 1 to 69.7% on day 10. The end‐of‐course evaluation revealed that 91% of students agreed they received effective teaching.

Conclusions

In response to the COVID‐19 pandemic, our multispecialty faculty expeditiously developed a virtual PoCUS curriculum for the entire fourth‐year class. This innovative course improved students’ ultrasound knowledge, image interpretation, and clinical application while utilizing novel techniques to teach a hands‐on skill virtually. As the demand for PoCUS instruction continues to increase, the accessibility of virtual training and blended learning will be beneficial.
Proximal variants in CCND2 associated with microcephaly, short stature, and developmental delay: A case series and review of inverse brain growth phenotypes
Authors: Pirozzi Filomena , Lee Benson , Horsley Nicole , Burkardt Deepika D. , Dobyns William B. , Graham John M. , Dentici Maria L. , Cesario Claudia , Schallner Jens , Porrmann Joseph , Di Donato Nataliya , Sanchez‐Lara Pedro A. , Mirzaa Ghayda M.
Published: June 2021

Cyclin D2 (CCND2) is a critical cell cycle regulator and key member of the cyclin D2‐CDK4 (DC) complex. De novo variants of CCND2 clustering in the distal part of the protein have been identified as pathogenic causes of brain overgrowth (megalencephaly, MEG) and severe cortical malformations in children including the megalencephaly‐polymicrogyria‐polydactyly‐hydrocephalus (MPPH) syndrome. Megalencephaly‐associated CCND2 variants are localized to the terminal exon and result in accumulation of degradation‐resistant protein. We identified five individuals from three unrelated families with novel variants in the proximal region of CCND2 associated with microcephaly, mildly simplified cortical gyral pattern, symmetric short stature, and mild developmental delay. Identified variants include de novo frameshift variants and a dominantly inherited stop‐gain variant segregating with the phenotype. This is the first reported association between proximal CCND2 variants and microcephaly, to our knowledge. This series expands the phenotypic spectrum of CCND2‐related disorders and suggests that distinct classes of CCND2 variants are associated with reciprocal effects on human brain growth (microcephaly and megalencephaly due to possible loss or gain of protein function, respectively), adding to the growing paradigm of inverse phenotypes due to dysregulation of key brain growth genes.
Atypical, severe hypertrophic cardiomyopathy in a newborn presenting Noonan syndrome harboring a recurrent heterozygous MRAS variant
Authors: Pires Lucas Vieira Lacerda , Bordim Renata de Almeida , Maciel Maria Beatriz Rabelo , Tanaka Ana Cristina Sayuri , Yamamoto Guilherme Lopes , Honjo Rachel Sayuri , Kim Chong Ae , Bertola Debora Romeo
Published: June 2021

Noonan syndrome (NS) is a Mendelian phenotype, member of a group of disorders sharing neurocardiofaciocutaneous involvement, known as RASopathies, caused by germline variants in genes coding for components of the RAS/MAPK signaling pathway. Recently, a novel gene of the RAS family (MRAS) was reported to be associated with NS in five children, all of them presenting, among the cardinal features of NS, the same cardiac finding, hypertrophic cardiomyopathy (HCM). We report on a 2‐month‐old infant boy also presenting this cardiac anomaly that evolved to a fatal outcome after a surgical myectomy. In addition, a thick walled left ventricle apical aneurysm, rarely described in NS, was also disclosed. Next‐generation sequencing revealed a missense, previously reported variant in MRAS (p.Thr68Ile). This report reinforces the high frequency of HCM among individuals harboring MRAS variants, contrasting to the 20% overall prevalence of this cardiac anomaly in NS. Thus, these preliminary data suggest that variants in MRAS per se are high risk factors for the development of an early, severe HCM, mostly of them with left ventricle outflow tract obstruction, with poor prognosis. Because of the severity of the cardiac involvement, other clinical findings could not be addressed in detail. Therefore, long‐term follow‐up of these individuals and further descriptions are required to fully understand the complete phenotypic spectrum of NS associated with MRAS germline variants, including if these individuals present an increased risk for cancer.
Facile Synthesis of Oleanane‐type Pentacyclic Triterpenoids Bearing Hydroxy Groups on D/E Rings
Authors: Mu Tong , Xu Peng , Yu Biao
Published: June 2021

Pentacyclic triterpenoids (PTs) comprise one of the largest class of natural products; many bear higher oxidation state on the D/E rings and exhibit a wide range of biological activities. Here, we report the chemical synthesis of a series of oleanane‐type PTs bearing hydroxy groups on D/E rings from the largely available oleanolic acid by transformations following site‐selective C−H hydroxylation.
Acute systemic inflammation exacerbates neuroinflammation in Alzheimer's disease: IL‐1β drives amplified responses in primed astrocytes and neuronal network dysfunction
Authors: Lopez‐Rodriguez Ana Belen , Hennessy Edel , Murray Carol L. , Nazmi Arshed , Delaney Hugh J. , Healy Dáire , Fagan Steven G. , Rooney Michael , Stewart Erika , Lewis Anouchka , de Barra Niamh , Scarry Philip , Riggs‐Miller Louise , Boche Delphine , Cunningham Mark O. , Cunningham Colm
Published: June 2021

Neuroinflammation contributes to Alzheimer's disease (AD) progression. Secondary inflammatory insults trigger delirium and can accelerate cognitive decline. Individual cellular contributors to this vulnerability require elucidation. Using APP/PS1 mice and AD brain, we studied secondary inflammatory insults to investigate hypersensitive responses in microglia, astrocytes, neurons, and human brain tissue. The NLRP3 inflammasome was assembled surrounding amyloid beta, and microglia were primed, facilitating exaggerated interleukin‐1β (IL‐1β) responses to subsequent LPS stimulation. Astrocytes were primed to produce exaggerated chemokine responses to intrahippocampal IL‐1β. Systemic LPS triggered microglial IL‐1β, astrocytic chemokines, IL‐6, and acute cognitive dysfunction, whereas IL‐1β disrupted hippocampal gamma rhythm, all selectively in APP/PS1 mice. Brains from AD patients with infection showed elevated IL‐1β and IL‐6 levels. Therefore, amyloid leaves the brain vulnerable to secondary inflammation at microglial, astrocytic, neuronal, and cognitive levels, and infection amplifies neuroinflammatory cytokine synthesis in humans. Exacerbation of neuroinflammation to produce deleterious outcomes like delirium and accelerated disease progression merits careful investigation in humans.
A Trapezoidal Octacyanoquinoid Acceptor Forms Solution and Surface Products by Antiparallel Shape Fitting with Conformational Dipole Momentum Switch
Authors: Medina Rivero Samara , Urieta‐Mora Javier , Molina‐Ontoria Agustín , Martín‐Fuentes Cristina , Urgel José I. , Zubiria‐Ulacia Maria , Lloveras Vega , Casanova David , Martínez José I. , Veciana Jaume , Écija David , Martín Nazario , Casado Juan
Published: June 2021

A new compound (1) formed by two antiparallelly disposed tetracyano thienoquinoidal units has been synthesized and studied by electrochemistry, UV/Vis‐NIR, IR, EPR, and transient spectroscopy. Self‐assembly of1on a Au(111) surface has been investigated by scanning tunneling microscopy. Experiments have been rationalized by quantum chemical calculations.1exhibits a unique charge distribution in its anionic form, with a gradient of charge yielding a neat molecular in‐plane electric dipole momentum, which transforms out‐of‐plane after surface deposition due to twisted→folded conformational change and to partial charge transfer from Au(111). Intermolecular van der Waals interactions and antiparallel trapezoidal shape fitting lead to the formation of an optimal dense on Au(111) two‐dimensional assembly of1.
Precisely Engineered Supported Gold Clusters as a Stable Catalyst for Propylene Epoxidation
Authors: Kapil Nidhi , Weissenberger Tobias , Cardinale Fabio , Trogadas Panagiotis , Nijhuis T. Alexander , Nigra Michael M. , Coppens Marc‐Olivier
Published: June 2021

Designing a stable and selective catalyst with high H2 utilisation is of pivotal importance for the direct gas‐phase epoxidation of propylene. This work describes a facile one‐pot methodology to synthesise ligand‐stabilised sub‐nanometre gold clusters immobilised onto a zeolitic support (TS‐1) to engineer a stable Au/TS‐1 catalyst. A non‐thermal O2 plasma technique is used for the quick removal of ligands with limited increase in particle size. Compared to untreated Au/TS‐1 catalysts prepared using the deposition precipitation method, the synthesised catalyst exhibits improved catalytic performance, including 10 times longer lifetime (>20 days), increased PO selectivity and hydrogen efficiency in direct gas phase epoxidation. The structure‐stability relationship of the catalyst is illustrated using multiple characterisation techniques, such as XPS, 31P MAS NMR, DR‐UV/VIS, HRTEM and TGA. It is hypothesised that the ligands play a guardian role in stabilising the Au particle size, which is vital in this reaction. This strategy is a promising approach towards designing a more stable heterogeneous catalyst.
Introducing Intermolecular Cation‐π Interactions for Water‐Stable Low Dimensional Hybrid Lead Halide Perovskites
Authors: Sheikh Tariq , Maqbool Shabnum , Mandal Pankaj , Nag Angshuman
Published: June 2021

Optoelectronically active hybrid lead halide perovskites dissociate in water. To prevent this dissociation, here, we introduce long‐range intermolecular cation‐π interactions between A‐site cations of hybrid perovskites. An aromatic diamine like 4,4′‐trimethylenedipyridine, if protonated, can show a long‐range cation‐π stacking, and therefore, serves as our A‐site cation. Consequently, 4,4′‐trimethylenedipyridinium lead bromide [(4,4′‐TMDP)Pb2Br6], a one‐dimensional hybrid perovskite, remains completely stable after continuous water treatment for six months. Mechanistic insights about the cation‐π interactions are obtained by single‐crystal X‐ray diffraction and nuclear magnetic resonance spectroscopy. The concept of long‐range cation‐π interaction is further extended to another A‐site cation 4,4′‐ethylenedipyridinium ion (4,4′‐EDP), forming water‐stable (4,4′‐EDP)Pb2Br6 perovskite. These water‐stable perovskites are then used to fabricate white light‐emitting diode and for light up‐conversion through tunable third‐harmonic generation. Note that the achieved water stability is the intrinsic stability of perovskite composition, unlike the prior approach of encapsulating the unstable perovskite material (or device) by water‐resistant materials. The introduced cation‐π interactions can be a breakthrough strategy in designing many more compositions of water‐stable low‐dimensional hybrid perovskites.
Origin of the α‐Effect in SN2 Reactions
Authors: Hansen Thomas , Vermeeren Pascal , Bickelhaupt F. Matthias , Hamlin Trevor A.
Published: June 2021

The α‐effect is a term used to explain the dramatically enhanced reactivity of α‐nucleophiles (R−Y−X:−) compared to their parent normal nucleophile (R−X:−) by deviating from the classical Brønsted‐type reactivity‐basicity relationship. The exact origin of this effect is, however, still heavily under debate. In this work, we have quantum chemically analyzed the α‐effect of a set of anionic nucleophiles, including O‐, N‐ and S‐based normal and α‐nucleophiles, participating in an SN2 reaction with ethyl chloride using relativistic density functional theory at ZORA‐OLYP/QZ4P. Our activation strain and Kohn–Sham molecular orbital analyses identified two criteria an α‐nucleophile needs to fulfill in order to show α‐effect: (i) a small HOMO lobe on the nucleophilic center, pointing towards the substrate, to reduce the repulsive occupied–occupied orbital overlap and hence (steric) Pauli repulsion with the substrate; and (ii) a sufficiently high energy HOMO to overcome the loss of favorable HOMO–LUMO orbital overlap with the substrate, as a consequence of the first criterion, by reducing the HOMO–LUMO orbital energy gap. If one of these two criteria is not fulfilled, one can expect no α‐effect or inverse α‐effect.
Two‐Photon Ionization Induced Stable White Organic Long Persistent Luminescence
Authors: Liang Xiao , Zheng You‐Xuan , Zuo Jing‐Lin
Published: June 2021

Organic long persistent luminescence (OLPL) materials with afterglow duration in the scale of minutes or even hours are still rare. Most OLPL systems are based on exciplexes, which require complicated multi‐component system in order to realize white afterglow but with slightly compromised duration and color stability. In this work, OLPLs lasting from 20 to 40 minutes are realized in a simple binary system based on two‐photon ionization mechanism, which can simultaneously harvest excitons from both singlet and triplet excited states, making it potentially one of the most promising candidates to achieve stable white OLPL. Through modulation and optimization of dopant molecules in dibenzo[b,d]thiophen‐2‐yldiphenyl phosphine oxide host, the emission profiles of afterglow can be readily tuned from cyan (0.19, 0.22), cold white (0.31, 0.35), standard white (0.33, 0.33) to warm white (0.31, 0.46), with excellent color consistency.
Talc reinforcement of polylactide and biodegradable polyester blends via injection‐molding and pilot‐scale film extrusion
Authors: Helanto Karoliina , Talja Riku , Rojas Orlando J.
Published: June 2021

As a renewable and biodegradable polymer, polylactide (PLA) has taken a foothold in the packaging industry. However, the thermomechanical and barrier properties of PLA‐based films need to be improved to facilitate a wider adoption. To address this challenge, we examined the effect of talc reinforcement in composites based on PLA and a biodegradable polyester. Masterbatches of the polymers and talc were produced by melt compounding and processed by either injection‐molding or film extrusion in a pilot‐scale unit operating at 60–80 m/min. The effect of talc was investigated in relation to the morphological, thermal, mechanical, and barrier properties of the composites. Based on SEM‐imaging, talc was found to increase the miscibility of PLA and the polyester while acting as a nucleating agent that improved PLA crystallinity. While this effect did not track with an increased mechanical strength, the composites with 3–4 wt% talc displayed a significantly higher barrier to water vapor. Compared to the neat polymer films, a reduction of water vapor transmission rate, by ~34–37%, was observed at 23°C/50% RH. Meanwhile, the systems loaded with 1 wt% talc showed a reduction in oxygen transmission rates, by up to 34%. Our results highlight the challenges and prospects of commercial PLA‐based blends filled with talc from films extruded in pilot‐scale units.
Tunable fluorescent and antimicrobial properties of poly(vinyl amine) affected by the acidic or basic hydrolysis of poly(N‐vinylformamide)
Authors: Sütekin S. Duygu , Demirci Sahin , Kurt Saliha B. , Güven Olgun , Sahiner Nurettin
Published: June 2021

Synthesis of poly(N‐vinylformamide) (PNVF) and its subsequent hydrolysis to convert it to poly(vinyl amine) (PVAm) were performed. Kinetics of acidic and basic hydrolysis of poly(N‐vinylformamide) (PNVF), and products of hydrolysis were investigated by using Fourier transform infrared, size exclusion chromatography,1H NMR, and13C NMR spectroscopies, and thermogravimetric analysis. It was observed that amide groups did not completely transform into amine groups by acidic hydrolysis of PNVF while the conversion of amides into amine groups via basic hydrolysis of PNVF was complete in 12 h, as confirmed by spectroscopic measurements. Results of extensive characterization revealed significant structural and conformational differences between acidic and basic hydrolysis products. Fluorescence spectroscopy was used for the first time to follow the conversion of amide groups into amine groups. The fluorescence intensity of PVAm obtained from basic hydrolysis of PVNF showed significant increase with amide/amine conversion. Finally, PVAm obtained from acidic hydrolysis of PNVF demonstrated potent antimicrobial activity, 10–20 times more, against common pathogens for example,C. albicans asfungal strain andE. coli,S. aureus,B. subtilis,andP. aeruginosaas bacterial strains as compared to PVAm obtained from basic hydrolysis.
Synthesis and biological evaluation of some 1‐naphthol derivatives as antioxidants, acetylcholinesterase, and carbonic anhydrase inhibitors
Authors: Erdoğan Musa , Polat Köse Leyla , Eşsiz Selçuk , Gülçin İlhami
Published: June 2021

A series of some naphthol derivatives 4a–f, 5a,f, 6a, and 7a,b (six novel ones: 4c,d, 5a, 6a, 7a,b) bearing F, Cl, Br, OMe, and dioxole substituents at different positions of the aromatic rings was designed, synthesized, and characterized. The naphthol derivatives were synthesized in three steps, namely the addition reaction of furan via Diels–Alder cycloaddition reaction, copper(II) trifluoromethanesulfonate (Cu(OTf)2)‐catalyzed aromatization reaction, and the bromination reaction, respectively. The structures of the newly obtained compounds (4c,d, 5a, 6a, 7a,b) were characterized by spectroscopic techniques. In addition, some biological activity studies were investigated under in vitro conditions. Inhibition studies of these compounds were performed on human carbonic anhydrase (hCA) I and II isoenzymes purified from human erythrocytes as a biological evaluation. Moreover, their potential antioxidant and antiradical activities were studied by analytical methods like ABTS•+ and DPPH• scavenging, and it was determined that some molecules showed good activity. Also, inhibition of acetylcholinesterase (AChE), which is a marker of many degenerative neurological diseases, was tested and the results were discussed. Excellent enzyme inhibition results were recorded for most of the molecules. These 1‐naphthol derivatives were found as effective inhibitors for hCA I, hCA II, and AChE with K
i values ranging from 0.034 ± 0.54 to 0.724 ± 0.18 µM for hCA I, 0.172 ± 0.02 to 0.562 ± 0.21 µM for hCA II, and 0.096 ± 0.01 to 0.177 ± 0.02 µM for AChE.