bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biopolitics, Pseudoscience and Science Denialism in the United States
Authors: Aramesh Kiarash 
Published: April 2021

AbstractAs the nation that hosts most of the leading institutions in biomedical sciences, the United States of America has been a major battleground between science versus biopolitics inspired pseudoscience and science denialism, especially in recent years. Two major examples of the latter are the antivaccination and antiquarantine movements. They incorporate various features of pseudoscience including working in isolation, evading peer review, escaping to the mass and social media, no self‐correction over time, relying on fictional or obsolete theories for nature, and having no boundaries for claims. They are harmful for society and in addition to promoting false ideas; they cause a lot of mortality and morbidity. Bioethics can provide an ethical framework to address such problems. Such framework consists of virtues, such as care and honesty; principles, such as social value and scientific validity, and case‐based approaches that can be implemented by institutions such as the Institutional Review Boards.Key ConceptsScience is the result of a history of honest and systematic efforts to remove biases and heuristics from the process of obtaining knowledge.Biopolitics is the interference of politics in the realm of life sciences.Following the good and reliable science entails adopting a scientific attitude, following valid scientific methods and conducting science in a democratised way.Not following the scientific standards where they should be followed leads to development of pseudoscience and science denialism. They are harmful for the society.Antivaccination and antiquarantine movements are two prominent examples of pseudoscience and science denialism in the United States of America.Bioethics can provide a framework to address biopolitics inspired pseudoscience and science denialism at different levels.The abovementioned bioethical framework entails Virtues such as honesty and care; principles, such as social value and scientific validity; and case‐based deliberations.
Algal Ciliary Motility
Authors: Hunter Emily L , Penny Gervette M , Dutcher Susan K 
Published: April 2021

AbstractThe microtubule‐based cilium (also known as a flagellum) extends from the surface of most eukaryotic cells. This long, slender organelle is biochemically complex and is conserved in many eukaryotic organisms. The unicellular alga,Chlamydomonas reinhardtii,serves as a tractable organism for studying the assembly and function of cilia. Cilia provide locomotion and environmental sensing. To produce motility, specialised molecular motors called outer and inner dynein arms generate force to produce waveform. These motors are regulated by other macromolecular complexes in the cilium. The ease of genetic and biochemical approaches combined with electron microscopy has provided the ability to perform in‐depth studies of the regulation of ciliary assembly and function. Results fromChlamydomonasresearchers have broadened our knowledge of motile cilia diseases in humans. There are still many outstanding questions to be addressed.Key ConceptsChlamydomonas reinhardtiiis a haploid, motile, single‐celled alga that is useful for the study of cilia.TheChlamydomonascilium is a complex structure that generates asymmetric and symmetric waveforms to allow forward and backward swimming, respectively, and orientation to environmental signals.During ciliary motility, dynein arms pull microtubule doublets past each other to generate sliding, which is converted into axonemal bending, although the mechanism for how this occurs is still controversial.Outer dynein arms control the ciliary beat frequency by changing the velocity of doublet sliding. Inner dynein arms in conjunction with the radial spokes and the central pair apparatus, control the bend amplitude and the shape of the waveform.The axoneme is divided into 96 nm repeating segments that contain regulatory, enzymatic and structural components essential for motility; these include the inner and outer dynein arms, N‐DRC, MIA complex and radial spokes as well as two central microtubules.IFT (intraflagellar transport) is essential for building the cilium by transporting cargo into (anterograde) and out of (retrograde) the cilium.Cell biological research about ciliary components, including the central pair apparatus, radial spokes and N‐DRC, provides key information about how ciliary motility is regulated.Genetic, biochemical and microscopic methods used inChlamydomonashave allowed molecular resolution of interactions between regulatory complexes.Studies ofChlamydomonascilia have provided additional insights to the structure, function and regulation of cilia, and have helped with the understanding of human cilia‐related diseases called ciliopathies.
Algal Metabolism
Authors: Beardall John , Raven John A 
Published: April 2021

Abstract

Algal metabolism concerns the biochemical and transport processes by which algae take up nutrients and convert them into the materials needed for growth, reproduction and defence of the organisms. Many of the metabolic processes that occur in algae are common to those found in other living organisms. This commonality is described, but emphasis is given to those major metabolic processes in algae that are unique to, or differ in detail from, those of other organisms. This includes mechanisms of light harvesting, carbon acquisition and aspects of N and S assimilation as well as the formation of unique secondary metabolites. In addition, the consequences for algal metabolism of growth in extreme environments, such as nutrient limitation and exposure to extremes of visible and UV light, are considered. The exploitation of algal metabolism and its products in biotechnology is also briefly described.

Key Concepts

Algal metabolism shares many features in common with that of other living organisms but also differs in unique respects.

Algal metabolism gives rise to a range of unique compounds, including secondary metabolites, some of which have toxicity to other organisms.

Algal metabolism is modulated to a large extent by environmental factors such as nutrient availability and extremes of temperature and light.

Certain algae can metabolise at lower external pH and lower PAR than can embryophytes.

Algal metabolism can be exploited to produce compounds of biotechnological importance. These include pigments, nutraceuticals, bioactive compounds and oils for biodiesel.
Peptidases
Authors: Rawlings Neil D , Barrett Alan J 
Published: April 2021

AbstractPeptidases are catalytically active proteins (enzymes) that cleave peptide bonds in proteins and peptides by hydrolysis. Not only do peptidases break down proteins and peptides so that the amino acids can be recycled and used during growth and remodelling, but they are also important for modifying proteins. These processing events ensure proteins are sent to the correct cellular or extracellular locations, are activated or inactivated when required, and that biologically important peptides are excised. There are six catalytic types (serine, cysteine, threonine, aspartic, glutamic and metallo). Peptidases can be classified by sequence similarities into approximately 400 families, and these, in turn, can be arranged into approximately 60 clans by comparing tertiary structures.Key ConceptsA peptidase is a catalytically active protein that cleaves one or more peptide bonds in a protein or peptide by hydrolysis.There are six different catalytic types of peptidases.Comparison of the amino acid sequences of peptidases allows them to be classified into about 400 families.Comparison of the structural folds of peptidases allows them to be classified into about 60 clans.A peptidase that acts only within three residues of the amino or carboxyl termini of a substrate protein is known as an exopeptidase.A peptidase that cleaves any bond in a substrate protein that is more than three residues from the amino or carboxyl termini is known as an endopeptidase.A peptidase has an active site containing amino acids that are important for catalysis and which are usually conserved in all active members of a family.The active site of a peptidase is flanked by substrate binding pockets, each of which accommodates one residue from the substrate.Some peptidases have additional substrate binding sites remote from the active site that are known as exosites.
Old World Monkeys
Authors: Frost Stephen R , Gilbert Christopher C 
Published: April 2021

Abstract

Old World monkeys, or cercopithecoids, are a diverse and widespread group of primates found throughout Africa and Asia. They are characterised by their specialised molar teeth, quadrupedal posture and locomotor behaviour, often spending more time on the ground than other primates, as well as their frequently large and complex social groups. They survive in the widest range of habitats of any nonhuman primates, with some species restricted to humid tropical forests while others are found in mountains and deserts. There are two main groups: the cercopithecines, which have cheek‐pouches and include macaques, baboons, mangabeys, vervets and guenons; and the colobines, characterised by complex stomach anatomy that allows them to digest leaves and which include langurs, proboscis monkeys, doucs and snub‐nosed monkeys and colobus monkeys. Although they are termed ‘monkeys’ they are more closely related to apes and humans (hominoids) than they are to the monkeys of Central and South America.

Key Concepts

As they are large, occur in large social groups, are often terrestrial and active during the day, Old World monkeys are some of the most thoroughly studied wild primates.

Groups of closely related females, called matrilines, usually form the core of Old World monkey social groups because females remain in the same group as their mothers, whereas males generally transfer to a new group when they become adults.

Old World monkeys are the most diverse group of primates in terms of environmental and geographic range, as well as number of species, but have achieved this diversity through relatively narrow morphological and behavioural adaptations that allow for ecological flexibility.

Compared to other primate groups, Old World monkeys are a recent adaptive radiation, which may in part explain their relative lack of anatomical diversity.

They replaced apes as the predominant primates in Africa and Eurasia over the past 5–7 million years as climatic change made environments more open and seasonal.
Distributed Kalman filter for linear system with complex multi‐channel stochastic uncertain parameter and decoupled local filters
Authors: Pu Shi , Yu Xingkai , Li Jianxun 
Published: April 2021

SummaryThis article considers a distributed Kalman filtering problem for linear system contaminated by complex multi‐channel random uncertain parameter in which a number of nodes cooperative without central coordination to estimate a common state based on local measurements and data received from neighbors. We propose an approach to eliminate this error propagation. The proposed local filters are guaranteed to be stable under some mild conditions on certain global structural data, and their fusion yields the centralized Kalman estimate. Then, we extend this method to smoothing and deconvolution algorithm. Finally, simulation experiments demonstrate the validity of the proposed approach.
Tuning the Photophysical and Electrochemical Properties of Aza‐Boron‐Dipyridylmethenes for Fluorescent Blue OLEDs
Authors: Tadle Abegail C. , El Roz Karim A. , Soh Chan Ho , Sylvinson Muthiah Ravinson Daniel , Djurovich Peter I. , Forrest Stephen R. , Thompson Mark E. 
Published: April 2021

AbstractA series of substituted aza‐boron‐dipyridylmethene (aD) compounds are demonstrated as fluorescent dopant emitters in blue organic light emitting diodes (OLEDs). Replacing the meso‐carbon of a dipyridylmethene dye with nitrogen to form the aD chromophore leads to a destabilization of the highest occupied molecular orbital in aD, as evidenced both from their experimentally determined photophysical and electrochemical properties. These properties are consistent with theoretical calculations of the molecular energetics. These aD derivatives emit violet to blue light, peaking between 400 and 460 nm with photoluminescent quantum yields over 85%. The aD compounds have small energy differences (<400 meV) between their singlet and triplet excited states. OLEDs fabricated with an aza‐boron‐dipyridylmethene emitting fluorophore give an external quantum efficiency of 4.5% on glass substrates, close to the theoretical maximum for fluorescent OLEDs.
Multivalent Aptamer‐Functionalized Single‐Strand RNA Origami as Effective, Target‐Specific Anticoagulants with Corresponding Reversal Agents
Authors: Krissanaprasit Abhichart , Key Carson M. , Froehlich Kristen , Pontula Sahil , Mihalko Emily , Dupont Daniel M. , Andersen Ebbe S. , Kjems Jørgen , Brown Ashley C. , LaBean Thomas H. 
Published: April 2021

AbstractAnticoagulants are commonly utilized during surgeries and to treat thrombotic diseases like stroke and deep vein thrombosis. However, conventional anticoagulants have serious side‐effects, narrow therapeutic windows, and lack safe reversal agents (antidotes). Here, an alternative RNA origami displaying RNA aptamers as target‐specific anticoagulant is described. Improved design and construction techniques for self‐folding, single‐molecule RNA origami as a platform for displaying pre‐selected RNA aptamers with precise orientational and spatial control are reported. Nuclease resistance is added using 2′‐fluoro‐modified pyrimidines during in vitro transcription. When four aptamers are displayed on the RNA origami platform, the measured thrombin inhibition and anticoagulation activity is higher than observed for free aptamers, ssRNA‐linked RNA aptamers, and RNA origami displaying fewer aptamers. Importantly, thrombin inhibition is immediately switched off by addition of specific reversal agents. Results for single‐stranded DNA (ssDNA) and single‐stranded peptide nucleic acid (PNA) antidotes show restoration of 63% and 95% coagulation activity, respectively. To demonstrate potential for practical, long‐term storage for clinical use, RNA origami is freeze‐dried, and stored at room temperature. Freshly produced and freeze‐dried RNA show identical levels of activity in coagulation assays. Compared to current commercial intravenous anticoagulants, RNA origami‐based molecules show promise as safer alternatives with rapid activity switching for future therapeutic applications.
Strategy for Designing a Cell Scaffold to Enable Wireless Electrical Stimulation for Enhanced Neuronal Differentiation of Stem Cells
Authors: Han Fang , Ma Xun , Zhai Yuanxin , Cui Leisha , Yang Lingyan , Zhu Zhanchi , Hao Ying , Cheng Guosheng 
Published: April 2021

AbstractElectrical stimulation (ES) offers significant advantages in modulating the behavior of stem cells on conductive scaffolds for neural tissue engineering. However, it is necessary to realize wireless ES to avoid the use of external wires in tissues. Thus, herein, a strategy is reported to develop a stem cell scaffold that allows wireless ES. A conductive annular graphene substrate is designed and grown by chemical vapor deposition; this substrate is used as a secondary coil to achieve wireless ES via electromagnetic induction in the presence of a primary coil. The substrate shows excellent biocompatibility for the culture of neural stem cells (NSCs). The results indicate that the applied wireless ES enhances neuronal differentiation, facilitates the formation of neurites, and does not substantially affect the viability and stemness maintenance of NSCs. Collectively, this system provides a strategy for achieving synergy between wireless ES and conductive scaffolds for neural regenerative medicine, which can be further utilized for the regeneration of other tissues.
A Biphasic Osteovascular Biomimetic Scaffold for Rapid and Self‐Sustained Endochondral Ossification
Authors: Kim Hwan D. , Hong Xuechong , An Young‐Hyeon , Park Mihn Jeong , Kim Do‐Gyoon , Greene Arin K. , Padwa Bonnie L. , Hwang Nathaniel S. , Lin Ruei‐Zeng , Melero‐Martin Juan M. 
Published: April 2021

AbstractRegeneration of large bones remains a challenge in surgery. Recent developmental engineering efforts aim to recapitulate endochondral ossification (EO), a critical step in bone formation. However, this process entails the condensation of mesenchymal stem cells (MSCs) into cartilaginous templates, which requires long‐term cultures and is challenging to scale up. Here, a biomimetic scaffold is developed that allows rapid and self‐sustained EO without initial hypertrophic chondrogenesis. The design comprises a porous chondroitin sulfate cryogel decorated with whitlockite calcium phosphate nanoparticles, and a soft hydrogel occupying the porous space. This composite scaffold enables human endothelial colony‐forming cells (ECFCs) and MSCs to rapidly assemble into osteovascular niches in immunodeficient mice. These niches contain ECFC‐lined blood vessels and perivascular MSCs that differentiate into RUNX2+OSX+ pre‐osteoblasts after one week in vivo. Subsequently, multiple ossification centers are formed, leading to de novo bone tissue formation by eight weeks, including mature human OCN+OPN+ osteoblasts, collagen‐rich mineralized extracellular matrix, hydroxyapatite, osteoclast activity, and gradual mechanical competence. The early establishment of blood vessels is essential, and grafts that do not contain ECFCs fail to produce osteovascular niches and ossification centers. The findings suggest a novel bioengineering approach to recapitulate EO in the context of human bone regeneration.
An Ultra‐Stable, Oxygen‐Supply Nanoprobe Emitting in Near‐Infrared‐II Window to Guide and Enhance Radiotherapy by Promoting Anti‐Tumor Immunity
Authors: Wang Meng , Li Hao , Huang Biao , Chen Song , Cui Ran , Sun Zhi‐Jun , Zhang Mingxi , Sun Taolei 
Published: April 2021

AbstractCurrently, radiotherapy (RT) is the main method for cancer treatment. However, the hypoxic environment of solid tumors is likely to cause resistance or failure of RT. Moreover, high‐dose radiation may cause side effects to surrounding normal tissues. In this study, a new type of nanozyme is developed by doping Mn (II) ions into Ag2Se quantum dots (QDs) emitting in the second near‐infrared window (NIR‐II, 1000–1700 nm). Through the catalysis of Mn (II) ions, the nanozymes can trigger the rapid decomposition of H2O2 and produce O2. Conjugated with tumor‐targeting arginine‐glycine‐aspartate (RGD) tripeptides and polyethylene glycol (PEG) molecules, the nanozymes are then constructed into in vivo nanoprobes for NIR‐II imaging‐guided RT of tumors. Owing to the radiosensitive activity of the element Ag, the nanoprobes can promote radiation energy deposition. The specific tumor‐targeting and NIR‐II emitting abilities of the nanoprobes facilitate the precise tumor localization, which enables precise RT with low side effects. Moreover, their ultra‐stability in the living body ensures that the nanoprobes continuously produce oxygen and relieve the hypoxia of tumors to enhance RT efficacy. Guided by real‐time and high‐clarity imaging, the nanoprobe‐mediated RT promotes anti‐tumor immunity, which significantly inhibits the growth of tumors or even cures them completely.
In Situ Interface Engineering with a Spiro‐OMeTAD/CoO Hierarchical Structure via One‐Step Spin‐Coating for Efficient and Stable Perovskite Solar Cells
Authors: Dou Yanfei , Zhang Lei , Li Guodong , Wang Xiaobing , Sun Weihai , Wu Jihuai , Lan Zhang 
Published: April 2021

AbstractInterface engineering plays crucial role for fabricating high efficiency perovskite solar cells (PSCs) because the trap defects, especially those existing at the interfaces, will become recombination centers during the generation and transport of photo‐generated charges and seriously influence photovoltaic performance. Commonly, interface engineering with semiconductor nanomaterials usually use ex situ method, which brings about more tedious fabricating steps. Here, a hierarchical structure is successfully fabricated with CoO nanoplates underneath and (N,N‐di‐p‐methoxyphenylamine)‐9,9′‐Spirobifluorene (Spiro‐OMeTAD) on top by one‐step spin‐coating the hybrid. This in situ formed CoO thin passivation layer shows functions for realizing better charge transport kinetics and effectively inhibiting dark recombination in the corresponding device. These benefits are propitious to achieving better photovoltaic performance and long‐term stability than those of the control one. Therefore, it is an easy and feasible way for interface engineering in the PSCs.
Crystalline Metal‐Organic Materials with Thermally Activated Delayed Fluorescence
Authors: Han Zhen , Dong Xi‐Yan , Zang Shuang‐Quan 
Published: April 2021

AbstractThermally activated delayed fluorescence (TADF) properties of crystalline metal‐organic materials, mainly including small‐molecule metal–organic complexes, organic ligand‐protected metal clusters, and metal‐organic coordination polymers are summarized here. The characteristics of TADF of each type of materials are discussed. Thermally activated delayed photoluminescence (TADPL) in quantum dots grafted organic chromophores is also briefly presented to highlight the difference from TADF. Finally, the perspectives of crystalline metal‐containing TADF emitters are discussed. Therefore, a panoramic view of recent advances in metal‐organic materials for TADF emitters is provided.
Interfacing Iodine‐Doped Hydrothermally Carbonized Carbon with Escherichia coli through an “Add‐on” Mode for Enhanced Light‐Driven Hydrogen Production
Authors: Xiao Kemeng , Tsang Tsz Ho , Sun Dong , Liang Jun , Zhao Hui , Jiang Zhifeng , Wang Bo , Yu Jimmy C. , Wong Po Keung 
Published: April 2021

AbstractThe recently emerged photosynthetic biohybrid systems (PBSs) integrate the advantages of the light‐harvesting ability of semiconductors and the catalytic power of biological metabolism. Herein, negatively charged iodine‐doped hydrothermally carbonized carbon (I‐HTCC) is interfaced with surface modified Escherichia coli cells through a facile “add‐on” mode via electrostatic interactions. As a result of the photoexcited electrons, the self‐assembled I‐HTCC@E. coli biohybrid shows enhanced hydrogen production efficiency with a quantum efficiency of 9.11% under irradiation. The transduction of photoelectrons from I‐HTCC to cells is the rate‐limiting step for H2 production and is delivered through both direct injection and the NADH/NAD+‐mediated pathways. The injected photoelectrons fine‐tune the H2 production through the formate and NADH pathways in a subtle manner. The excellent biocompatibility and photostability of the I‐HTCC@E. coli biohybrid demonstrate its potential real‐world application under sunlight. In addition, the proposed “add‐on” mode is extended to a series of negatively charged common carbon‐based materials with different levels of promotion effects compared with that of pure bacterial cultures. This facile and effective mode provides an insight into the rational design of the whole‐cell PBSs with various semiconductors for H2 production.