bluuebunny/crossref_metadata_2025 huggingface dataset:
Distinguishing three effects of time pressure on risk taking: Choice consistency, risk preference, and strategy selection
Authors: Olschewski Sebastian , Rieskamp Jörg
Published: January 2021

Quick decision making under risk is ubiquitous in modern times, yet its consequences are not fully understood. Time pressure might change people's risk preferences, lead to less consistent choices, or change people's decision strategy. With the present work, we make the novel contribution of testing all hypotheses against each other in a unifying hierarchical Bayesian model. In two studies, participants decided repeatedly between two risky gambles either with or without high time pressure. We found a significant increase in risky choices under time pressure. With modeling, we show that time pressure decreased choice consistency but did not systematically affect people's risk preferences. In addition, the number of participants using simple, noncompensatory strategies increased slightly under time pressure. Finally, participants did not systematically choose easier gambles more often under time pressure. Thus, a reliable analysis of the effect of time pressure on preferential choice requires a model framework that allows for the distinction between the various effects time pressure can have.
Electromagnetic Irradiation Evokes Physiological and Molecular Alterations in Rice
Authors: Kundu Ardhendu , Vangaru Sathish , Bhattacharyya Somnath , Mallick Amirul I. , Gupta Bhaskar
Published: January 2021

Electromagnetic energy is the “backbone” of wireless communication systems, and its progressive use is considered to have a low but measurable impact on a wide range of biological systems. Even though a growing amount of data has reported electromagnetic energy absorption in humans along with subsequent biological effects, the consequences of electromagnetic energy absorption on plants have been insufficiently addressed. The higher surface to volume ratio along with the enormous water‐ion concentrations makes the plant an ideal model to interact with non‐ionizing electromagnetic radiation. In this study, controlled and periodic electromagnetic exposure of 1837.50 MHz, 2.75 W/m2 for 6 h a day on a popular rice variety (var. Satabdi) reduced the seed germination rate. The same dose of periodic electromagnetic exposure upregulated phytochrome B and phytochrome C gene transcripts in 12‐day‐old seedlings, whereas, in 32‐day‐old plants, the dose upregulated calmodulin and phytochrome C while the bZIP1 gene showed repression. However, the transcript abundance of bZIP1, phytochrome B, and phytochrome C genes was enhanced even in 12‐day‐old Satabdi seedlings following instantaneous short‐duration (2 h 30 min) controlled electromagnetic exposure to 1837.50 MHz, 2.75 W/m2. The reported responses in rice were observed below the international electromagnetic regulatory limits. Thus, rice plants perceived electromagnetic energy emitted by the wireless communication system as abiotic stress as per its response by upregulation or repression of known stress‐sensing genes. Bioelectromagnetics. © 2020 Bioelectromagnetics Society
Physical ‘strength’ of the multi‐protein chain connecting immune cells: Does the weakest link limit antibody affinity maturation?
Authors: Desikan Rajat , Antia Rustom , Dixit Narendra M.
Published: January 2021

The affinities of antibodies (Abs) for their target antigens (Ags) gradually increase in vivo following an infection or vaccination, but reach saturation at values well below those realisable in vitro. This ‘affinity ceiling’ could in many cases restrict our ability to fight infections and compromise vaccines. What determines the affinity ceiling has been an unresolved question for decades. Here, we argue that it arises from the strength of the chain of protein complexes that is pulled by B cells during the process of Ag acquisition. The affinity ceiling is determined by the strength of the weakest link in the chain. We identify the weakest link and show that the resulting affinity ceiling can explain the Ab affinities realized in vivo, providing a conceptual understanding of Ab affinity maturation. We explore plausible evolutionary underpinnings of the affinity ceiling, examine supporting evidence and alternative hypotheses and discuss implications for vaccination strategies.
Role of luteolin in overcoming Parkinson's disease
Authors: Siddique Yasir Hasan
Published: January 2021

Parkinson's disease (PD) is the second most common neurodegenerative disorder affecting elderly people (>60 years old) worldwide. There is no permanent cure for the disease but the symptomatic relief can be obtained by using dopamine agonists besides L‐dopa therapy. The longer use of the drugs is associated with several side effects. Hence, the researchers have made a considerable attention toward the development of neuroprotective agents from plants. A number of phytochemicals have been demonstrated for their protective effects in various in vitro, in vivo, and clinical studies. In this context, luteolin, a flavone which is present in fruits and vegetables has been attributed to a number of pharmacological properties including neuroprotective. The present review demonstrates the bioavailability, oral absorption, and mechanism of action against PD.
Online discussions in biochemistry to increase peer interactions and student interest
Authors: Wilson Kristy J.
Published: January 2021

The online environment poses a number of challenges, including creating opportunities for students to interact and get to know each other. I propose adding online discussions that can allow students to explore the real‐world implications of biochemistry to provide course context, build the classroom community, diversify student assessment, and practice communication and information literacy skills. Utilizing current events and elements of students' daily lives can help students interconnect what they are learning and increase student interest in the course. These discussions ask students to explore a topic, reflect on what they would like to learn, find information, and report back on what they have learned. Herein I provide an example of a discussion prompt, a table of other potential discussion topics that are aligned with common biochemistry course topics, and results from student survey supporting discussion format.
Phenotypic characterization of frontal cortex microglia in a rat model of post‐traumatic stress disorder
Authors: Cotrone Thomas S. , Hocog Charina B. , Ramsey Joseph T. , Sanchez Marcus A. , Sullivan Heather M. , Scrimgeour Angus G.
Published: January 2021

Introduction

Post‐traumatic stress disorder (PTSD) is an anxiety disorder induced by psychologically traumatic events. Using a rat model, this study aimed to determine whether psychological trauma alters relative expression between pro‐inflammatory and anti‐inflammatory markers in microglia. To meet this goal, expression of genes encoding i‐NOS, arginase, TNF‐α, interleukin‐10, CD74, and Mannose Receptor C was analyzed on multiple days following trauma exposure.

Methods

Single‐prolonged stress (SPS) was used to model PTSD in male Sprague‐Dawley rats. Twenty‐four rats (12 Controls and 12 SPS‐exposed) were sacrificed on Days 1, 3, and 7 post‐SPS. Twenty‐four (12 Controls and 12 SPS‐exposed) additional rats were exposed to classical fear conditioning on Day 7, and fear extinction on Days 8, 9, 10, 15, 16, and 17. Freezing behavior was measured to assess fear resolution. Microglial isolates were collected from the frontal cortex, and RNA was extracted. Changes in relative expression of target genes were quantified via RT‐PCR.

Results

SPS rats showed significant decreases in IL‐10 and TNF‐α expression and increases in the i‐NOS:Arginase and TNF‐α:IL‐10 ratios compared to Controls on Day 1, but not on Day 3 or Day 7 for any of the dependent variables. Day 17 SPS rats showed a significant decrease in IL‐10 expression and an increase in the TNF‐α:IL‐10 ratio, further characterized by a significant inverse relationship between IL‐10 expression and fear persistence.

Conclusion

Psychological trauma impacts the immunological phenotype of microglia of the frontal cortex. Consequently, future studies should further evaluate the mechanistic role of microglia in PTSD pathology.
Implementing circular economy in the textile and clothing industry
Authors: Saha Krishnendu , Dey Prasanta Kumar , Papagiannaki Eleni
Published: January 2021

This research reveals the current state of the circular economy (CE), challenges and opportunities of implementing CE and interventions that could facilitate effective implementation of CE in the textile and clothing (TC) industry. The study uses a survey method within 114 TC companies based in Bangladesh, Vietnam and India revealing the correlation of CE fields of action (take, make, distribute, use and recover) with sustainability (economic, environmental and social) performance. The lack of financial, technological and human resources along with management's reluctance and end‐user's indifference to sustainability is the biggest challenge for CE implementation. The research further derives that the TC firms are unable to eradicate the challenges to CE implementation without a holistic approach that involves the collective effort from the industry, host government's incentives, their buyers and above all the conscience of the end‐users. Finally, the study reveals that the collaborative efforts, knowledge sharing in sustainability management across the value chain and marketisation of the waste recycling, among others, are a few actions the stakeholders of the TC industry must adopt for implementing CE successfully.
How to innovate business models for a circular bio‐economy?
Authors: Donner Mechthild , de Vries Hugo
Published: January 2021

Shifting from a linear to a circular bio‐economy requires new business models. The objective was getting insights into the uncharted research field of business model innovation for a circular and sustainable bio‐economy within the agrifood sector. Eight European cases valorising agricultural waste and by‐products by closing loops or cascading were studied regarding their innovation drivers and elements, via interviews, on‐site visits and secondary data. In this domain, the findings highlight that business model innovations are depending on the (i) macro‐environmental institutional‐legal conditions and market trends, (ii) driven by internal economic, environmental and/or social objectives, but especially strongly linked to (iii) other actors often from different sectors seeking synergies and (iv) value co‐creation via combined organisational and technological innovations. Business models for a circular bio‐economy thus depend on various action levels and need radical combined organisational and technological innovations for a most efficient usage of agricultural waste and by‐products. This also means new business configurations instead of linear innovation strategies currently still being dominant due to economic viability.
Model‐based workflow for scale‐up of process strategies developed in miniaturized bioreactor systems
Authors: Arndt Lukas , Wiegmann Vincent , Kuchemüller Kim B. , Baganz Frank , Pörtner Ralf , Möller Johannes
Published: January 2021

Miniaturized bioreactor (MBR) systems are routinely used in the development of mammalian cell culture processes. However, scale‐up of process strategies obtained in MBR‐ to larger scale is challenging due to mainly non‐holistic scale‐up approaches. In this study, a model‐based workflow is introduced to quantify differences in the process dynamics between bioreactor scales and thus enable a more knowledge‐driven scale‐up. The workflow is applied to two case studies with antibody‐producing Chinese hamster ovary cell lines. With the workflow, model parameter distributions are estimated first under consideration of experimental variability for different scales. Second, the obtained individual model parameter distributions are tested for statistical differences. In case of significant differences, model parametric distributions are transferred between the scales. In case study I, a fed‐batch process in a microtiter plate (4 ml working volume) and lab‐scale bioreactor (3750 ml working volume) was mathematically modeled and evaluated. No significant differences were identified for model parameter distributions reflecting process dynamics. Therefore, the microtiter plate can be applied as scale‐down tool for the lab‐scale bioreactor. In case study II, a fed‐batch process in a 24‐Deep‐Well‐Plate (2 ml working volume) and shake flask (40 ml working volume) with two feed media was investigated. Model parameter distributions showed significant differences. Thus, process strategies were mathematically transferred, and model predictions were simulated for a new shake flask culture setup and confirmed in validation experiments. Overall, the workflow enables a knowledge‐driven evaluation of scale‐up for a more efficient bioprocess design and optimization.
Synthetic biology in biofilms: Tools, challenges, and opportunities
Authors: Tran Peter , Prindle Arthur
Published: January 2021

The field of synthetic biology seeks to program living cells to perform novel functions with applications ranging from environmental biosensing to smart cell‐based therapeutics. Bacteria are an especially attractive chassis organism due to their rapid growth, ease of genetic manipulation, and ability to persist across many environmental niches. Despite significant progress in bacterial synthetic biology, programming bacteria to perform novel functions outside the well‐controlled laboratory context remains challenging. In contrast to planktonic laboratory growth, bacteria in nature predominately reside in the context of densely packed communities known as biofilms. While biofilms have historically been considered environmental and biomedical hazards, their physiology and emergent behaviors could be leveraged for synthetic biology to engineer more capable and robust bacteria. Specifically, bacteria within biofilms participate in complex emergent behaviors such as collective organization, cell‐to‐cell signaling, and division of labor. Understanding and utilizing these properties can enable the effective deployment of engineered bacteria into natural target environments. Toward this goal, this review summarizes the current state of synthetic biology in biofilms by highlighting new molecular tools and remaining biological challenges. Looking to future opportunities, advancing synthetic biology in biofilms will enable the next generation of smart cell‐based technologies for use in medicine, biomanufacturing, and environmental remediation.
Mismatch repair protein and MLH1 methylation status as predictors of response to adjuvant therapy in endometrial cancer
Authors: Loukovaara Mikko , Pasanen Annukka , Bützow Ralf
Published: January 2021

Background

Mismatch repair (MMR) system has been implicated in the response of mammalian cells to ionizing radiation and DNA damaging agents. We investigated the value of the MMR system in predicting response to adjuvant therapy in endometrial cancer.

Methods

This was a single institution retrospective study. MMR protein status of endometrial carcinomas was assessed by immunohistochemistry. MMR deficient (MMR‐D) tumors were identified as MLH1 methylated or nonmethylated by methylation‐specific multiplex ligation‐dependent probe amplification. Tumors with abnormal p53 staining or polymerase ϵ exonuclease domain mutation were excluded from the MMR proficient subgroup, which was termed as “no specific molecular profile” (NSMP). Disease‐specific survival analyses were adjusted for age, stage, histology and grade, depth of myometrial invasion, and lymphovascular space invasion.

Results

A total of 505 patients were included in the study. Median follow‐up time was 81 months (range 1–136). Whole pelvic radiotherapy (adjusted hazard ratio [HR] 0.092 vs. no adjuvant therapy) and chemotherapy combined with radiotherapy (adjusted HR 0.18) were associated with improved disease‐specific survival in the NSMP subgroup (n = 218). In contrast, adjuvant therapies showed no effect on disease‐specific survival in the full MMR‐D cohort (n = 287) or in MLH1 methylated tumors (n = 154). Whole pelvic radiotherapy (adjusted HR 25 vs. no adjuvant therapy/vaginal brachytherapy) and chemotherapy combined with whole pelvic radiotherapy (adjusted HR 32) were associated with poor disease‐specific survival in MMR‐D nonmethylated tumors (n = 70).

Conclusion

MMR protein and MLH1 methylation status predict the response to adjuvant therapy in endometrial cancer. The MMR system could be utilized for selection of patients who most likely benefit from adjuvant therapy.
The Comparative Analysis of Carboxylic Acid Composition of Four Iris Species from Ukraine
Authors: Mykhailenko Olha , Gudžinskas Zigmantas , Romanova Svitlana , Orlova Tetyana , Kozyra Sofiia , Harna Svitlana , Volochai Victoriia
Published: January 2021

The present article reports results of analysis of carboxylic acids in leaves of Iris species from Ukraine using a gas chromatography (GC) method with mass spectrometric (MS) detection (GC/MS). Carboxylic acids play significant roles in contemporary society as evidenced by multiple applications in fields of medicine, agriculture, pharmacy, food, and other industries. Study of natural plant products as a source of organic acids is of particular interest. Carboxylic acid composition of leaves of Iris hungarica Waldst. & Kit., Iris germanica L., Iris pallida Lam., and Iris variegate L. was studied for the first time applying GC/MS method. The mass spectrums of compounds were matched with NIST and WILEY Libraries. The GC/MS analysis revealed the presence of 26 common acids in the plant raw materials studied. The short‐chain carboxylic acids, such as citric (1337.5–12364.4 mg/kg), malic (50.8–4558.0 mg/kg) and oxalic (1199.0–3435.2 mg/kg) acids were contained in significantly high quantity in all samples. Ferulic, p‐coumaric and vanillic acids were the most abundant among phenolic acids. α‐Linolenic acid was dominant in the leaves of I. germanica (869.5 mg/kg), I. pallida (753.3 mg/kg), and I. variegate (250.3 mg/kg) among polyunsaturated fatty acids, however, linoleic acid prevailed in the plant raw material of I. hungarica (1150.7 mg/kg). Since the leaves of Iris species studied contain carboxylic acids with diverse pharmacological activity, extracts of these raw materials are perspective for development food supplements and medicines.
IsPETase Is a Novel Biocatalyst for Poly(ethylene terephthalate) (PET) Hydrolysis
Authors: Kan Yeyi , He Lihui , Luo Yunzi , Bao Rui
Published: January 2021

Poly(ethylene terephthalate) (PET) is one of the most widely used synthetic polyesters, but also a major cause of plastic pollution. Because the chemical degradation of PET would be uneconomical and rather burdensome, considerable efforts have been devoted to exploring enzymatic processes for the disposal of PET waste. Many PET‐hydrolyzing enzymes have been reported in recent decades, some of which demonstrate excellent potential for industrial applications. This review sets out to summarize the state of investigation into IsPETase, a cutinase‐like enzyme from Ideonella sakaiensis possessing ability to degrade crystalline PET, and to gain further insight into the structure–function relationship of IsPETase. Benefiting from the continuing identification of novel cutinase‐like proteins and growing availability of the engineered IsPETase, we may anticipate future developments in this type of enzyme would generate suitable biocatalyst for industrial use.
Cleavage of an RNA Model Compound by an Arylmercury Complex
Authors: Saleh Lange Yakubu , Ora Mikko , Lönnberg Tuomas
Published: January 2021

A water‐soluble arylmercury complex has been synthesized, and its ability to catalyze the cleavage of the phosphodiester linkage of the RNA model compound adenylyl‐3′,5′‐(2′,3′‐O‐methyleneadenosine) has been assessed over a pH range of 3–8.5 and a catalyst concentration range of 0–7 mM. In the presence of 1 mM catalyst, the observed pH–rate profile featured a new pH‐independent region between pH 6 and 7, the catalyzed reaction being as much as eight times faster than the background reaction. At pH 7, the acceleration increased linearly from three‐ to 17‐fold upon increasing the catalyst concentration from 1 to 7 mM. The linear dependence indicates a relatively low affinity of the catalyst for the substrate and, hence, the potential for considerable improvement on tethering to an appropriate targeting group, such as an oligonucleotide.
High‐Performance Reversed‐Phase Flash Chromatography Purification of Peptides and Chemically Modified Insulins
Authors: Sørensen Kasper K. , Mishra Narendra K. , Paprocki Maciej P. , Mehrotra Amit , Jensen Knud J.
Published: January 2021

Preparative reversed‐phase HPLC is the established method for the purification of peptides, but has significant limitations. We systematically investigated the use of high‐performance reversed‐phase flash chromatography (HPFC) to rapidly purify laboratory‐scale quantities of crude, synthetic peptides and chemically modified insulins. We demonstrated these methods for a diverse set of peptides, including short, medium, and long peptides. Depending on the purity profile of the peptide, HPFC can be used either as the sole purification method, or as a pre‐purification method prior to final HPLC purification. Furthermore, HPFC is suitable for the purification of peptides that are not fully in solution. We provide guidelines for the HPFC of synthetic peptides and small proteins, including the choice of columns, eluents, and gradients. We believe that HPFC is a valuable alternative to HPLC purification of peptides and small proteins.
COVID‐19: Prolonged viral shedding in an HIV patient with literature review of risk factors for prolonged viral shedding and its implications for isolation strategies
Authors: Yousaf Muhammad , Hameed Mansoor , Alsoub Hussam , Khatib Mohamad , Jamal Wasim , Ahmad Mushtaq
Published: January 2021

Our work highlights patients at risk of prolonged viral shedding in COVID‐19 and its implications for isolation strategies and explores possible solution by PCR‐CT value testing (cycle threshold value). We also review the impact of HIV on COVID‐19.
A multilobulated asymptomatic umbilical nodule revealing endometriosis
Authors: Chamli Amal , Souissi Asmahene , Alaoui Fatima , Chelly Ines , Eleuch Dalenda , Mokni Mourad
Published: January 2021

Primary umbilical endometriosis is unusual clinical presentation of endometriosis. Its diagnosis can be challenging due to lack of knowledge. This condition should be listed in the differential diagnosis of umbilical disorders.
Cooperative NHC‐based Catalytic System Immobilised onto Carbon Materials for the Cycloaddition of CO2 to Epoxides
Authors: Souleymanou Myriam Y. , El‐Ouahabi Fatima , Masdeu‐Bultó Anna M. , Godard Cyril
Published: January 2021

New pyrene‐tagged imidazolium salts and their corresponding carboxylates were synthesised and the latter tested as organocatalysts in the cycloaddition of CO2 with epoxides. The best performing organocatalyst was then non‐covalently immobilised onto carbon materials (carbon nanotubes (CNTs), reduced graphene oxide (rGO) and carbon beads (CBs)) via π‐π stacking interactions and their activity and recoverability in the cycloaddition reaction were studied. The heterogenised catalyst onto reduced graphene oxide (4 a@rGO) was recycled several times although a loss of activity was observed. This catalyst was also used for the transformation of a series of epoxides under mild conditions.
Promotion of Electrochemical Water Oxidation Activity of Au Supported Cobalt Oxide upon Addition of Cr: Insights using in situ Raman Spectroscopy
Authors: Das Abhinaba , Mohapatra Bapuji , Kamboj Vipin , Ranjan Chinmoy
Published: January 2021

Mixed metal oxides based on cobalt oxide are important target material as water oxidation catalyst in alkaline media. Significant enhancement of electrochemical oxygen evolution activity was observed for Au supported cobalt oxide, upon addition of Cr. CoOx/Au and Co[Cr]Ox/Au were studied side by side to understand the effects of the addition of Cr in such a system. The presence of Cr resulted in a significant lowering of onset potentials ∼150 mV. In‐situ Raman spectroscopy was used to characterize the material. The catalyst was found to develop into oxide entirely in situ. Cr was found to stabilize lower oxidation states of Co, both during catalyst formation and oxygen evolution. Isotopic substitution studies alongside in situ Raman Spectroscopy showed that OER onset potential strongly correlated with the appearance of metastable Au−OOH peak.
Electro‐Oxidation of Titanium Carbide Nanoparticles in Aqueous Acid Creates TiC@TiO2 Core‐Shell Structures
Authors: Nayak Pranati , Xie Ruo‐Chen , Palgrave Robert G. , Compton Richard G.
Published: January 2021

Titanium carbide (TiC) is an attractive support material used in electro‐catalysis and sensing. We report the electrochemistry of TiC nanoparticles (NPs, 35–50 nm in diameter) in different electrolytes in the pH range of 0 to 8. The TiC NPs undergo irreversible oxidation in acidic, basic, and neutral media, attributed to the partial conversion into titanium dioxide (TiO2) with the amount of oxidation highly dependent on the pH of the solution. In H2SO4 (pH 0), multiple voltammetric scans revealed the conversion to be partial but repeated scans allowed a conversion approaching 100 % to be obtained with 20 scans generating a ca 60 % level of oxidation. The process is inferred to lead to the formation of TiC@TiO2 core‐shell nanoparticles (∼12.5 nm core radius and ∼5 nm shell width for a 60 % conversion) and this value sharply decreases with an increase of pH. Independent measurements were conducted at a single NP level (via nano‐impact experiments) to confirm the oxidation of the NPs, showing consistent agreement with the bulk measurements.
A new concept based on ensemble strategy and derivative for the quantitative analysis of infrared data
Authors: Yan Hong , Tang Guo , Xiong Yanmei , Min Shungeng
Published: January 2021

Preprocessing and variable selection are the most widely used strategies to develop accurate predictive models based on infrared spectroscopy. In our study, a new conception that the derivative combined with ensemble strategy based on competitive adaptive reweighted sampling (CARS), stability competitive adaptive reweighted sampling (SCARS), Monte Carlo uninformative variables elimination (MCUVE), and bootstrapping soft shrinkage (BOSS) is put forward. The proposed concept makes the best of the derivative spectra information and successfully combines the strengths of derivative spectra, CARS, SCARS, MCUVE, BOSS, and ensemble submodels. Compared with other methods in this study, this new method can establish good calibration models without increasing the complexity from the perspective of an end user. Also, overfitting issues can be prevented. Derivative1st‐ECARS and Derivative1st‐ESCARS have shown significant improvements in partial least regression calibration based on the experiments of three datasets. The proposed concept shows great potential of the chemometrics approaches applied to infrared data in multivariate calibration.
The synthesis of carbon microspheres film composed of nano‐onions and its application as flexible supercapacitors
Authors: Zhang Miao , Zhao Naiqin , Li Xifei
Published: January 2021

Flexible electrodes with superior mechanical and electrochemical properties are essential for flexible supercapacitors. A convenient and scalable colloidal film‐assisted chemical vapor deposition (CF‐CVD) method is developed for the one‐step fabrication of the carbon microspheres films composed of carbon nano‐onions (CMS‐CNO films). The influence of growth conditions (such as growth temperature, time, and gas ratio) during CF‐CVD process on the carbon structures and the growth mechanism of the CMS‐CNO films have been investigated. By controlling the growth conditions, the controllable preparation of CMS‐CNO films is realized. Such binder‐free films can be used for the assembly of flexible supercapacitors, and unique architecture can achieve excellent performance. Benefitting from the composite of nano‐micro zero dimensional structures, the performance of the film in supercapacitors is remarkably improved. At the current density of 5 mA cm−2, the area‐specific capacity can be 903 mF cm−2. When the current density is increased to 500 mA cm−2, the area‐specific capacity can be increased to 729 mF cm−2. This simple and low‐cost preparation process and the superb electrochemical performance suggest great potential applications of CMS‐CNO films in flexible supercapacitors.
Mechanochemical Synthesis of Catalytic Materials
Authors: Amrute Amol P. , De Bellis Jacopo , Felderhoff Michael , Schüth Ferdi
Published: January 2021

The mechanochemical synthesis of nanomaterials for catalytic applications is a growing research field due to its simplicity, scalability, and eco‐friendliness. Besides, it provides materials with distinct features, such as nanocrystallinity, high defect concentration, and close interaction of the components in a system, which are, in most cases, unattainable by conventional routes. Consequently, this research field has recently become highly popular, particularly for the preparation of catalytic materials for various applications, ranging from chemical production over energy conversion catalysis to environmental protection. In this Review, recent studies on mechanochemistry for the synthesis of catalytic materials are discussed. Emphasis is placed on the straightforwardness of the mechanochemical route—in contrast to more conventional synthesis—in fabricating the materials, which otherwise often require harsh conditions. Distinct material properties achieved by mechanochemistry are related to their improved catalytic performance.
Selective Cross‐Coupling of Unsaturated Substrates on AlI
Authors: Dmitrienko Anton , Pilkington Melanie , Nikonov Georgii I.
Published: January 2021

The AlI compound NacNacAl (1, NacNac = [ArNC(Me)CHC(Me)NAr]−, Ar = 2,6‐iPr2C6H3) serves as a template for the chemoselective coupling between carbonyls (benzophenone, fenchone, isophorone, p‐tolyl benzoate, N,N‐dimethylbenzamide, (1‐phenylethylidene)aniline) and pyridine. With the CH‐acidic ketone (1R)‐(+) camphor, the reaction affords a hydrido alkoxide compound of Al, formed as the result of enolization, whereas an enolizable imine, (1‐phenylethylidene)aniline, and the bulky ketone isophorone, still chemoselectively couple with pyridine. In contrast, reaction with the ester p‐tolyl benzoate results in cleavage of the ester bond together with replacement of the alkoxy group by a hydrogen atom of the pyridine moiety. This study demonstrates that for carbonyl substrates featuring phenyl substituents, the reaction proceeds via intermediate formation of η2(C,X)‐coordinated (X = O, N) carbonyl adducts, whereas the reaction of 1 with (R)‐(−)‐fenchone in the absence of pyridine leads to CH activation in the pendant isopropyl group of the Ar substituent of the NacNac ligand.
Trends and Prospects of Bimetallic Exsolution
Authors: Tang Chenyang , Kousi Kalliopi , Neagu Dragos , Metcalfe Ian S.
Published: January 2021

Supported bimetallic nanoparticles used for various chemical transformations appear to be more appealing than their monometallic counterparts, because of their unique properties mainly originating from the synergistic effects between the two different metals. Exsolution, a relatively new preparation method for supported nanoparticles, has earned increasing attention for bimetallic systems in the past decade, not only due to the high stability of the resulting nanoparticles but also for the potential to control key particle properties (size, composition, structure, morphology, etc.). In this review, we summarize the trends and advances on exsolution of bimetallic systems and provide prospects for future studies in this field.
Synthesis and Electronic Properties of Directly Linked Dihydrodiazatetracene Dimers
Authors: Tanaka Katsuki , Sakamaki Daisuke , Fujiwara Hideki
Published: January 2021

5,12‐Dihydro‐5,12‐diazatetracene (DHDAT) dimers with different substitution patterns are synthesized: a symmetric one with a C−C bond between the monomer units (1) and two asymmetric ones with a C−N bond between the monomer units (2 and 3). The DHDAT units are planar in the C−C linked dimer 1 but perpendicularly oriented in the C−N linked dimers 2 and 3 (from X‐ray analysis). The electronic ground‐state interaction between the two units is large in 1 and small in 2 and 3. The emission behavior of 3 is different from that of other dimers and its monomer; it displays positive solvatochromism, characteristic for electron donor–acceptor molecules, despite its donor–donor type structure. Compound 3 exhibits a unique multi‐step thermochromic emission behavior. The emission behavior is attributed to the asymmetric distribution of the HOMO and LUMO of DHDAT.
Total Synthesis of Tiacumicin B: Study of the Challenging β‐Selective Glycosylations**
Authors: Tresse Cédric , François‐Heude Marc , Servajean Vincent , Ravinder Rubal , Lesieur Clémence , Geiben Lucie , Jeanne‐Julien Louis , Steinmetz Vincent , Retailleau Pascal , Roulland Emmanuel , Beau Jean‐Marie , Norsikian Stéphanie
Published: January 2021

We give a full account of the total synthesis of tiacumicin B (Tcn‐B), a natural glycosylated macrolide with remarkable antibiotic properties. Our strategy is based on our experience with the synthesis of the tiacumicin B aglycone and on unique 1,2‐cis‐glycosylation steps. We used sulfoxide anomeric leaving‐groups in combination with a remote 3‐O‐picoloyl group on the donors that allowed highly β‐selective rhamnosylation and noviosylation that rely on H‐bond‐mediated aglycone delivery. The rhamnosylated C1–C3 fragment was anchored to the C4–C19 aglycone fragment by a Suzuki–Miyaura cross‐coupling. Ring‐size‐selective Shiina macrolactonization provided a semiglycosylated aglycone that was engaged directly in the noviolysation step with a virtually total β‐selectivity. Finally, a novel deprotection method was devised for the removal of a 2‐naphthylmethyl ether on a phenol, and efficient removal of all the protecting groups provided synthetic tiacumicin B.
Bambusuril Macrocycles as Mediators of Supramolecular Interactions: Application to the Europium Cage Helicate
Authors: Hamacek Josef , Sokolov Jan , Šindelář Vladimír
Published: January 2021

Herein, it is shown how bambusurils can be used for tuning and/or characterizing supramolecular systems. Indeed, the addition of bambusurils as anion scavengers to metal‐mediated self‐assemblies allows manipulation of the subtle equilibria in the given system. This is demonstrated for the case of the tetranuclear europium helical cage, which is well suited to different applications. Among the reported results, experimental evidence is provided showing that perchlorate and triflate anions act as a molecular template for the cage assembly. The complexation of inorganic anions with neutral bambusurils resulted in bulky non‐coordinating counterions that may trigger the self‐assembly process or stimulate specific interactions between components. Moreover, bambusuril was able to selectively remove coordinating nitrates from the mixture with non‐coordinating anions, enabling the regeneration of the helical cage.
5‐Aza‐7‐deazaguanine–Isoguanine and Guanine–Isoguanine Base Pairs in Watson–Crick DNA: The Impact of Purine Tracts, Clickable Dendritic Side Chains, and Pyrene Adducts
Authors: Zhang Aigui , Kondhare Dasharath , Leonard Peter , Seela Frank
Published: January 2021

The Watson–Crick coding system depends on the molecular recognition of complementary purine and pyrimidine bases. Now, the construction of hybrid DNAs with Watson–Crick and purine–purine base pairs decorated with dendritic side chains was performed. Oligonucleotides with single and multiple incorporations of 5‐aza‐7‐deaza‐2′‐deoxyguanosine, its tripropargylamine derivative, and 2′‐deoxyisoguanosine were synthesized. Duplex stability decreased if single modified purine–purine base pairs were inserted, but increased if pyrene residues were introduced by click chemistry. A growing number of consecutive 5‐aza‐7‐deazaguanine–isoguanine base pairs led to strong stepwise duplex stabilization, a phenomenon not observed for the guanine–isoguanine base pair. Spacious residues are well accommodated in the large groove of purine–purine DNA tracts. Changes to the global helical structure monitored by circular dichroism spectroscopy show the impact of functionalization to the global double‐helix structure. This study explores new areas of molecular recognition realized by purine base pairs that are complementary in hydrogen bonding, but not in size, relative to canonical pairs.
Chiral Triptycenes: Concepts, Progress and Prospects
Authors: Khan Md. Nasim , Wirth Thomas
Published: January 2021

Triptycenes have been established as unique scaffolds because of their backbone π‐structure with a propeller‐like shape and saddle‐like cavities. They are some of the key organic molecules that have been extensively studied in polymer chemistry, in supramolecular chemistry and in material science. Triptycenes become chiral molecules when substituents are unsymmetrically attached in at least two of their different aromatic rings. This Minireview highlights the chirality of triptycenes from basics to an advanced stage for the development of functional molecules.
The Simplest Model for Doped Poly(3,4‐ethylenedioxythiophene) (PEDOT): Single‐crystalline EDOT Dimer Radical Cation Salts
Authors: Kameyama Ryohei , Fujino Tomoko , Dekura Shun , Kawamura Mitsuaki , Ozaki Taisuke , Mori Hatsumi
Published: January 2021

Although doped poly(3,4‐ethylenedioxythiophene) (PEDOT) is extensively used in electronic devices, their molecular‐weight distributions and inadequately defined structures have hindered the elucidation of their underlying conduction mechanism. In this study, we introduce the simplest discrete oligomer models: EDOT dimer radical cation salts. Single‐crystal structural analyses revealed their one‐dimensional (1D) columnar structures, in which the donors were uniformly stacked. Band calculations identified 1D metallic band structures with a strong intracolumnar orbital interaction (band width W≈1 eV), implying the origin of the high conductivity of doped PEDOT. Interestingly, the salts exhibited semiconducting behavior reminiscent of genuine Mott states as a result of electron–electron repulsion (U) dominant over W. This study realized basic models with tunable W and U to understand the conduction mechanism of doped PEDOT through structural modification in oligomers, including the conjugation length.
Pd‐Catalyzed C(sp2)−H Alkoxycarbonylation of Phenethyl‐ and Benzylamines with Chloroformates as CO Surrogates
Authors: Andrade‐Sampedro Paula , Matxain Jon M. , Correa Arkaitz
Published: January 2021

The site‐selective functionalization of C−H bonds within a complex molecule remains a challenging task of capital synthetic importance. Herein, an unprecedented Pd‐catalyzed C(sp2)−H alkoxycarbonylation of phenylalanine derivatives and other amines featuring picolinamide as the directing group (DG) is reported. This oxidative coupling is distinguished by its scalability, operational simplicity, and avoids the use of toxic carbon monoxide as the C1 source. Remarkably, the easy cleavage of the DG enables the efficient assembly of isoindolinone compounds. Density Functional Theory calculations support a PdII/PdIV catalytic cycle.
Extended Peptide Nucleic Acid Nucleobases Based on Isoorotic Acid for the Recognition of A–U Base Pairs in Double‐Stranded RNA
Authors: Brodyagin Nikita , Maryniak Aubrey L. , Kumpina Ilze , Talbott John M. , Katkevics Martins , Rozners Eriks , MacKay James A.
Published: January 2021

Peptide nucleic acids (PNA) with extended isoorotamide containing nucleobases (Io) were designed for binding A–U base pairs in double‐stranded RNA. Isothermal titration calorimetry and UV thermal melting experiments revealed improved affinity for A–U using the Io scaffold in PNA. PNAs having four sequential Io extended nucleobases maintained high binding affinity.
Chlorophyll‐Based Organic Heterojunction on Ti3C2Tx MXene Nanosheets for Efficient Hydrogen Production
Authors: Li Yuanlin , Sun Yuliang , Zheng Tianfang , Dall'Agnese Yohan , Dall'Agnese Chunxiang , Meng Xing , Sasaki Shin‐ichi , Tamiaki Hitoshi , Wang Xiao‐Feng
Published: January 2021

The Z‐scheme process is a photoinduced electron‐transfer pathway in natural oxygenic photosynthesis involving electron transport from photosystem II (PSII) to photosystem I (PSI). Inspired by the interesting Z‐scheme process, herein a photocatalytic hydrogen evolution reaction (HER) employing chlorophyll (Chl) derivatives, Chl‐1 and Chl‐2, on the surface of Ti3C2Tx MXene with two‐dimensional accordion‐like morphology, forming Chl‐1@Chl‐2@Ti3C2Tx composite, is demonstrated. Due to the frontier molecular orbital energy alignments of Chl‐1 and Chl‐2, sublayer Chl‐1 is a simulation of PSI, whereas upper layer Chl‐2 is equivalent to PSII, and the resultant electron transport can take place from Chl‐2 to Chl‐1. Under the illumination of visible light (>420 nm), the HER performance of Chl‐1@Chl‐2@Ti3C2Tx photocatalyst was found to be as high as 143 μmol h−1 gcat−1, which was substantially higher than that of photocatalysts of either Chl‐1@Ti3C2Tx (20 μmol h−1 g−1) or Chl‐2@Ti3C2Tx (15 μmol h−1 g−1).
Zirconium Catalyzed Hydroaminoalkylation for the Synthesis of α‐Arylated Amines and N‐Heterocycles
Authors: Koperniku Ana , Schafer Laurel L.
Published: January 2021

The zirconium catalyzed hydroaminoalkylation of alkenes with N‐aryl‐ and sterically demanding N‐alkyl‐α‐arylated secondary amines by using commercially available Zr(NMe2)4 is reported. N‐phenyl‐ and N‐isopropylbenzylamine are used as amine substrates to establish the alkene substrate scope. Exclusively linear products are obtained in the presence of bulky vinylsilanes. Challenging α‐heteroarylated amines and functionalized alkene substrates are compatible with this easy to use catalyst, affording a new disconnection strategy for the atom‐ and step‐economic preparation of selectively substituted saturated α‐arylated heterocycles.
Tuning Tetrazole Photochemistry for Protein Ligation and Molecular Imaging
Authors: Fay Rachael , Holland Jason P.
Published: January 2021

Photochemistry provides a wide range of alternative reagents that hold potential for use in bimolecular functionalisation of proteins. Here, we report the synthesis and characterisation of metal ion binding chelates derivatised with disubstituted tetrazoles for the photoradiochemical labelling of monoclonal antibodies (mAbs). The photophysical properties of tetrazoles featuring extended aromatic systems and auxochromic substituents to tune excitation toward longer wavelengths (365 and 395 nm) were studied. Two photoactivatable chelates based on desferrioxamine B (DFO) and the aza‐macrocycle NODAGA were functionalised with a tetrazole and developed for protein labelling with 89Zr, 64Cu and 68Ga radionuclides. DFO‐tetrazole (1) was assessed by direct conjugation to formulated trastuzumab and subsequent radiolabelling with 89Zr. Radiochemical studies and cellular‐based binding assays demonstrated that the radiotracer remained stable in vitro retained high immunoreactivity. Positron emission tomography (PET) imaging and biodistribution studies were used to measure the tumour specific uptake and pharmacokinetic profile in mice bearing SK‐OV‐3 xenografts. Experiments demonstrate that tetrazole‐based photochemistry is a viable approach for the light‐induced synthesis of PET radiotracers.
Hydrothermal Dissolution of Technical Grade Vitreous Silica in NaOH Solutions to Liquid Water Glasses with Higher SiO2:Na2O Ratios
Authors: Pfeiffer Thomas , Enke Dirk , Roggendorf Hans
Published: January 2021

Technical grade vitreous silica was dissolved hydrothermally in NaOH lyes. Liquid sodium water glasses with silica concentrations of up to 26.4 wt % and molar SiO2:Na2O ratios of up to 3.5 were obtained. The dissolution behavior showed two temperature regimes: up to 130 °C the SiO2 content approached a final solubility limit controlled by cristobalite crystallization. Above 130 °C, crystallization of low quartz restricted solubility. The dissolution kinetics were governed by surface area reduction and saturation control according to the Noyce‐Whitney law.
Calibration of solids concentration optical fibre probes with solids‐polymer blocks
Authors: Shabanian Jaber , Mokhtari Mojtaba , Chaouki Jamal
Published: January 2021

Owing to the determinant effects of the local distribution of solids concentration on transport phenomena, particularly in gas‐solids flows in such processing units as gas‐solid fluidized beds and pneumatic conveying lines, its accurate measurement has received considerable attention. Despite the widespread applications of optical fibre probes for the measurement of local solids concentration, these instruments may create measurement uncertainties due to their structural designs and challenges in their accurate calibrations. Several calibration methods have been proposed in the literature, while they need to be further improved. In the present study, we calibrated in‐house, fabricated, solids concentration mixed parallel optical fibre probes by two sets of solids‐polymer blocks covering solids volume fractions in the range of 0‐0.30. The uniform blocks were produced by a twin‐screw extruder and an injection moulding machine. FCC particles, 86 μm in diameter, formed the dispersed solids in the blocks, while poly styrene and poly methyl methacrylate were separately acting as the transparent medium. They helped us investigate the effects of the refractive index of the medium and the probe tip design on the calibration curve. The blind distance (zone) in front of the adopted probes was determined, at about 0.70 mm, upon measuring their reflective curves. Two glass windows with 1.00 and 1.60 mm thicknesses were separately installed at the tip of a probe to study their effects on the calibration curve. Experimental results indicated that in the absence of a glass window, the probes' voltage readings varied nonlinearly with solids concentration, the voltage readings were higher for blocks with a higher refractive index of the transparent medium, while the normalized calibration curves were similar for both sets of solids‐polymer blocks. In addition, the extent of the uniform distribution of illuminating and reflecting fibre strands at the tip of a mixed parallel optical fibre probe can change the degree of nonlinearity of its calibration curve. The application of glass windows thicker than the blind distance decreased the degree of nonlinearity of the calibration curve, yet did not completely eliminate it.
Preparation of Cu(І) Decorated 2D Black Phosphorus Nanosheets for Adsorption Desulfurization from Model Fuel
Authors: Wang Jie , Ma Hongqin , Li Jia , Luo Xinyue , Yu Luqi
Published: January 2021

In this study, Cu(І) decorated two‐dimensional black phosphorus nanosheets (BPNSs) adsorbents were prepared by a ball‐milling method, and their adsorption‐desorption performances were tested by batch adsorption experiments. The results showed that Cu(ІI) can be completely reduced to Cu(І) without adding any additional reducing agents during the ball‐milling process, owing to the ability of black phosphorus to provide electrons to Cu(ІI). Moreover, the produced Cu(І) species were firmly anchored on BPNSs surface through chemical bonds formed between Cu and P atoms, effectively preventing them from aggregating. As the active sites on BPNSs surface, Cu(I) species can adsorb dibenzothiophene or benzothiophene from fuel by forming π‐complexation bonds with them. The maximum adsorption capacity of the adsorbent for dibenzothiophene and benzothiophene were 13.16 and 18.02 mg S/g, respectively. Besides, the adsorption desulfurization activity can be recovered well by adopting simple thermal treatment.