bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanochemical Adhesion and Plasticity in Multifiber Hydrogel Networks
Authors: Davidson Matthew D. , Ban Ehsan , Schoonen Anna C. M. , Lee Mu‐Huan , D'Este Matteo , Shenoy Vivek B. , Burdick Jason A.
Published: December 2019

The extracellular matrix (ECM) has force‐responsive (i.e., mechanochemical) properties that enable adaptation to mechanical loading through changes in fibrous network structure and interfiber bonding. Imparting such properties into synthetic fibrous materials will allow reinforcement under mechanical load, the potential for material self‐adhesion, and the general mimicking of ECM. Multifiber hydrogel networks are developed through the electrospinning of multiple fibrous hydrogel populations, where fibers contain complementary chemical moieties (e.g., aldehyde and hydrazide groups) that form covalent bonds within minutes when brought into contact under mechanical load. These fiber interactions lead to microscale anisotropy, as well as increased material stiffness and plastic deformation. Macroscale structures (e.g., tubes and layered scaffolds) are fabricated from these materials through interfiber bonding and adhesion when placed into contact while maintaining a microscale fibrous architecture. The design principles for engineering plasticity described can be applied to numerous material systems to introduce unique properties, from textiles to biomedical applications.
Dipolar Substitution Impacts Growth and Electronic Properties of Para‐Sexiphenyl Thin Films
Authors: Hu Jiaxin , Aghdassi Nabi , Bhagat Shubham , Garmshausen Yves , Wang Rongbin , Koch Norbert , Hecht Stefan , Duhm Steffen , Salzmann Ingo
Published: December 2019

It is shown that fluorination of para‐sexiphenyl (6P) at the meta‐ or ortho‐positions of one terminal phenyl ring, as well as the addition of a terminal cyano‐group has an eminent impact on both growth and electronic properties of thin films. X‐ray diffraction techniques indicate that films of meta‐substituted 6P (m‐2F‐6P) develop a smooth, layered structure showing crystalline order within the layers only. Contrary, both ortho‐substituted (o‐2F‐6P) and cyano‐substituted 6P (CN‐6P) form films of 3D crystalline order. The correlation of structural information with data from ultraviolet photoelectron spectroscopy reveals that m‐2F‐6P and CN‐6P do not show preferentially oriented dipoles in the film, while o‐2F‐6P grows with collective downward orientation of the dipole moments. The subtle difference in substitution position has a dramatic impact on the thin‐film ionization energy, which increases from 5.40 (ortho) to 6.80 eV (meta) and reaches even 7.50 eV for CN‐6P. The present study shows that nonsymmetric substitution, which induces molecular dipole moments via intramolecular polar bonds, strongly impacts structure, morphology, and electronic properties of thin films. Thusly modifying common conjugated organic materials represents a valuable tool to establish smooth, crystalline layers with altered energetics at hetero‐interfaces with organic or electrode materials in electronic devices.
Selective Growth of Zn–Co–Se Nanostructures on Various Conductive Substrates for Asymmetric Flexible Hybrid Supercapacitor with Enhanced Performance
Authors: Chebrolu Venkata Thulasivarma , Balakrishnan Balamuralitharan , Chinnadurai Deviprasath , Kim Hee‐Je
Published: December 2019

Hybrid supercapacitors have received great interest in the field of electric vehicles and wearable electronic devices. However, developing new electrode material with high capacity and supporting substrates with good stability is still a big challenge. Herein, a facile electrodeposition technique is applied to grow Zn–Co–Se on various conductive substrates for hybrid supercapacitor. Among all, NF‐supported Zn–Co–Se electrode shows a high specific capacitance of 313.45 C g−1 and good cyclical stability of 95% retention over 3000 cycles. Interestingly, the assembled hybrid supercapacitor (Zn–Co–Se @Graphene–Ink) as the core and the outer electrode yield an ultrahigh energy density of ≈16.97 W h kg−1 at a power density of ≈539.63 W kg−1 with a maximum operating voltage of 1.6 V. Even at high power density of 13 499 W kg−1, the energy density can still retain 7.76 W h kg−1 with excellent cycling performance of 95% of capacity maintenance after 5000 cycles. For the real‐time applications, a series of two ASC devices could light up blue and green (LEDs) with high intensity and a multifunction sensor monitoring time with temperature and humidity is operated. Hence, the work presents a fresh route for designing metal selenides for energy storage and conversion applications.
Biopolymer Electrolyte Membranes (BioPEMs) for Sustainable Primary Redox Batteries
Authors: Alday Perla Patricia , Barros Sandra Cerqueira , Alves Raquel , Esperança José M. S. S. , Navarro‐Segarra Marina , Sabaté Neus , Silva Maria Manuela , Esquivel Juan Pablo
Published: December 2019

The proliferation of portable electronic devices has resulted in an increase of e‐waste that is generated after their use. One of the most hazardous components in e‐waste are batteries, due to their content of heavy metals and toxic chemicals. Fuel cells and redox flow batteries have been recognized as more sustainable alternatives to Li‐based batteries for powering portable applications. Although they provide comparable energy and power densities, they still face some challenges because they rely on proton exchange membranes based on nonenvironmentally friendly, high‐priced perfluorosulfonic acid copolymers that require energy‐intense manufacturing and recycling procedures. In this work, eco‐friendly and sustainable biopolymer electrolyte membranes (BioPEMs) are synthesized from biopolymers like chitosan, cellulose, and starch. These BioPEMs bring forth advantages in performance, sustainability, and cost. Additionally, they present good chemical and mechanical stability, high ionic conductivity in the same order of magnitude as Nafion membranes. Two alternatives of cellulose–chitosan based BioPEMs are successfully applied into primary redox batteries using benign eco‐friendly redox chemistries, delivering open circuit voltages above 0.75 V and power output up to 2.5 mW cm−2. These results demonstrate BioPEMs capability to improve biodegradable batteries in sectors requiring a transient electrical energy, such as environmental monitoring, agriculture, or packaging.
A Model to Study Myelinated Fiber Degeneration and Regeneration in Human Skin
Authors: Provitera Vincenzo , Piscosquito Giuseppe , Manganelli Fiore , Mozzillo Stefania , Caporaso Giuseppe , Stancanelli Annamaria , Borreca Ilaria , Di Caprio Giovanni , Santoro Lucio , Nolano Maria
Published: December 2019

Objective

To describe morphological changes associated with degeneration and regeneration of large fibers in the skin using a model of chronic compression of the median nerve.

Methods

We studied cutaneous innervation in 30 patients with chronic compression of the median nerve at the wrist. Before surgery, we assessed the symptom severity and performed neurography, quantitative sensory testing, and analysis of nerve morphology and morphometry in skin biopsies from the third digit fingertip. Fifteen patients repeated all tests 12 months after the surgery. Thirty age‐ and sex‐matched healthy subjects were included in the study.

Results

Clinical and neurophysiological basal assessment showed a moderate involvement of the median nerve. Quantitative sensory testing showed abnormal findings. The density of intraepidermal nerve fibers and intrapapillary myelinated endings was reduced. Myelinated fibers showed caliber reduction and nodal elongation. Meissner corpuscles had normal density but were located deeper in the dermis and their capsule appeared partially empty. During follow‐up, patients exhibited a positive clinical and neurophysiological outcome. Quantitative sensory testing improved. Intraepidermal nerve fibers and intrapapillary myelinated endings remained unchanged, but the caliber of intrapapillary myelinated endings was increased. The neural component of the Meissner corpuscle filled the capsule of the mechanoreceptors that remained deeper in the dermis. The position of vasoactive intestinal peptide–immunoreactive fibers was more superficial compared to the basal assessment and controls.

Interpretation

We recognized and quantified the pathological changes associated with nerve degeneration and regeneration in skin and proposed new parameters that may increase the diagnostic yield of skin biopsy in clinical practice. Ann Neurol 2020;87:456–465
Impact of Positional Isomerism on Pathway Complexity in Aqueous Media
Authors: Helmers Ingo , Shen Bowen , Kartha Kalathil K. , Albuquerque Rodrigo Q. , Lee Myongsoo , Fernández Gustavo
Published: December 2019

Pathway complexity has become an important topic in recent years due to its relevance in the optimization of molecular assembly processes, which typically require precise sample preparation protocols. Alternatively, competing aggregation pathways can be controlled by molecular design, which primarily rely on geometrical changes of the building blocks. However, understanding how to control pathway complexity by molecular design remains elusive and new approaches are needed. Herein, we exploit positional isomerism as a new molecular design strategy for pathway control in aqueous self‐assembly. We compare the self‐assembly of two carboxyl‐functionalized amphiphilic BODIPY dyes that solely differ in the relative position of functional groups. Placement of the carboxyl group at the 2‐position enables efficient pairwise H‐bonding interactions into a single thermodynamic species, whereas meso‐substitution induces pathway complexity due to competing hydrophobic and hydrogen bonding interactions. Our results show the importance of positional engineering for pathway control in aqueous self‐assembly.
Molecular‐Sieving Membrane by Partitioning the Channels in Ultrafiltration Membrane by In Situ Polymerization
Authors: Shao Pengpeng , Yao Ruxin , Li Ge , Zhang Mengxi , Yuan Shuai , Wang Xiaoqi , Zhu Yuhao , Zhang Xianming , Zhang Lin , Feng Xiao , Wang Bo
Published: December 2019

Commercial ultrafiltration membranes have proliferated globally for water treatment. However, their pore sizes are too large to sieve gases. Conjugated microporous polymers (CMPs) feature well‐developed microporosity yet are difficult to be fabricated into membranes. Herein, we report a strategy to prepare molecular‐sieving membranes by partitioning the mesoscopic channels in water ultrafiltration membrane (PSU) into ultra‐micropores by space‐confined polymerization of multi‐functionalized rigid building units. Nine CMP@PSU membranes were obtained, and their separation performance for H2/CO2, H2/N2, and H2/CH4 pairs surpass the Robeson upper bound and rival against the best of those reported membranes. Furthermore, highly crosslinked skeletons inside the channels result in the structural robustness and transfer into the excellent aging resistance of the CMP@PSU. This strategy may shed light on the design and fabrication of high‐performance polymeric gas separation membranes.
Graphitic Carbon Nitride (g‐C3N4): An Interface Enabler for Solid‐State Lithium Metal Batteries
Authors: Huang Ying , Chen Bo , Duan Jian , Yang Fei , Wang Tengrui , Wang Zhengfeng , Yang Wenjuan , Hu Chenchen , Luo Wei , Huang Yunhui
Published: December 2019

Solid‐state Li metal batteries (SSLMBs) have attracted considerable interests due to their promising energy density as well as high safety. However, the realization of a well‐matched Li metal/solid‐state electrolyte (SSE) interface remains challenging. Herein, we report g‐C3N4 as a new interface enabler. We discover that introducing g‐C3N4 into Li metal can not only convert the Li metal/garnet‐type SSE interface from point contact to intimate contact but also greatly enhance the capability to suppress the dendritic Li formation because of the greatly enhanced viscosity, decreased surface tension of molten Li, and the in situ formation of Li3N at the interface. Thus, the resulting Li‐C3N4|SSE|Li‐C3N4 symmetric cell gives a significantly low interfacial resistance of 11 Ω cm2 and a high critical current density (CCD) of 1500 μA cm−2. In contrast, the same symmetric cell configuration with pristine Li metal electrodes has a much larger interfacial resistance (428 Ω cm2) and a much lower CCD (50 μA cm−2).
A Supported Bismuth Halide Perovskite Photocatalyst for Selective Aliphatic and Aromatic C–H Bond Activation
Authors: Dai Yitao , Poidevin Corentin , Ochoa‐Hernández Cristina , Auer Alexander A. , Tüysüz Harun
Published: December 2019

Direct selective oxidation of hydrocarbons to oxygenates by O2 is challenging. Catalysts are limited by the low activity and narrow application scope, and the main focus is on active C−H bonds at benzylic positions. In this work, stable, lead‐free, Cs3Bi2Br9 halide perovskites are integrated within the pore channels of mesoporous SBA‐15 silica and demonstrate their photocatalytic potentials for C−H bond activation. The composite photocatalysts can effectively oxidize hydrocarbons (C5 to C16 including aromatic and aliphatic alkanes) with a conversion rate up to 32900 μmol gcat−1 h−1 and excellent selectivity (>99 %) towards aldehydes and ketones under visible‐light irradiation. Isotopic labeling, in situ spectroscopic studies, and DFT calculations reveal that well‐dispersed small perovskite nanoparticles (2–5 nm) possess enhanced electron–hole separation and a close contact with hydrocarbons that facilitates C(sp3)−H bond activation by photoinduced charges.
Uncovering the Shuttle Effect in Organic Batteries and Counter‐Strategies Thereof: A Case Study of the N,N′‐Dimethylphenazine Cathode
Authors: Lau Vincent Wing‐hei , Moudrakovski Igor , Yang Junghoon , Zhang Jiliang , Kang Yong‐Mook
Published: December 2019

The main drawback of organic electrode materials is their solubility in the electrolyte, leading to the shuttle effect. Using N,N′‐dimethylphenazine (DMPZ) as a highly soluble cathode material, and its PF6− and triflimide salts as models for its first oxidation state, a poor correlation was found between solubility and battery operability. Extensive electrochemical experiments suggest that the shuttle effect is unlikely to be mediated by molecular diffusion as commonly understood, but rather by electron‐hopping via the electron self‐exchange reaction based on spectroscopic results. These findings led to two counter‐strategies to prevent the hopping process: the pre‐treatment of the anode to form a solid–electrolyte interface and using DMPZ salt rather than neutral DMPZ as the active material. These strategies improved coulombic efficiency and capacity retention, demonstrating that solubility of organic materials does not necessarily exclude their applications in batteries.
A Dirhoda‐Heterocyclic Carbene
Authors: Barnett Harrison J. , Hill Anthony F.
Published: December 2019

The linear μ‐carbido complex [Rh2(μ‐C)Cl2(dppm)2] (dppm=bis(diphenylphosphino)methane) reacts with dimethylacetylene dicarboxylate (DMAD) to afford [Rh2(μ‐C)(μ‐DMAD)Cl2(dppm)2], which features a bent RhCRh linkage (124.7°) that might be described as a dirhoda‐heterocyclic carbene, as demonstrated by coordination to further metal centers.
Rapid One‐Step Synthesis and Compaction of High‐Performance n‐Type Mg3Sb2 Thermoelectrics
Authors: Zhang Jiawei , Song Lirong , Iversen Bo Brummerstedt
Published: December 2019

n‐type Mg3Sb2‐based compounds have emerged as a promising class of low‐cost thermoelectric materials due to their extraordinary performance at low and intermediate temperatures. However, so far, high thermoelectric performance has merely been reported in n‐type Mg3Sb2‐Mg3Bi2 alloys with a large amount of Bi. Moreover, current synthesis methods of n‐type Mg3Sb2 bulk thermoelectrics involve multi‐step processes that are time‐ and energy‐consuming. Herein, we report a fast and straightforward approach to fabricate n‐type Mg3Sb2 thermoelectrics using spark plasma sintering, which combines the synthesis and compaction in one step. Using this method, we achieve a high thermoelectric figure of merit zT of about 0.4–1.5 at 300–725 K in n‐type (Sc, Te)‐co‐doped Mg3Sb2 without alloying with Mg3Bi2. In comparison with the currently reported synthesis methods, the complexity, process time, and cost of our method are significantly reduced. This work demonstrates a simple, low‐cost route for the potential large‐scale production of n‐type Mg3Sb2 thermoelectrics.
Artificial Light‐Harvesting Complexes Enable Rieske Oxygenase Catalyzed Hydroxylations in Non‐Photosynthetic cells
Authors: Feyza Özgen F. , Runda Michael E. , Burek Bastien O. , Wied Peter , Bloh Jonathan Z. , Kourist Robert , Schmidt Sandy
Published: December 2019

In this study, we coupled a well‐established whole‐cell system based on E. coli via light‐harvesting complexes to Rieske oxygenase (RO)‐catalyzed hydroxylations in vivo. Although these enzymes represent very promising biocatalysts, their practical applicability is hampered by their dependency on NAD(P)H as well as their multicomponent nature and intrinsic instability in cell‐free systems. In order to explore the boundaries of E. coli as chassis for artificial photosynthesis, and due to the reported instability of ROs, we used these challenging enzymes as a model system. The light‐driven approach relies on light‐harvesting complexes such as eosin Y, 5(6)‐carboxyeosin, and rose bengal and sacrificial electron donors (EDTA, MOPS, and MES) that were easily taken up by the cells. The obtained product formations of up to 1.3 g L−1 and rates of up to 1.6 mm h−1 demonstrate that this is a comparable approach to typical whole‐cell transformations in E. coli. The applicability of this photocatalytic synthesis has been demonstrated and represents the first example of a photoinduced RO system.
An Indium‐Seamed Hexameric Metal–Organic Cage as an Example of a Hexameric Pyrogallol[4]arene Capsule Conjoined Exclusively by Trivalent Metal Ions
Authors: Wagle Durgesh V. , Kelley Steven P. , Baker Gary A. , Sikligar Kanishka , Atwood Jerry L.
Published: December 2019

A hexameric metal–organic nanocapsule is assembled from pyrogallol[4]arene units, which are stitched together with indium ions. This indium‐seamed capsule is the first instance of a M24L6 type hexameric coordination cage held together exclusively by trivalent metal ions. Explicitly, unlike previously reported pyrogallol[4]arene‐based metal‐seamed capsules, the current In3+ seamed capsule is entirely supported by O→In coordinate bonds. This work demonstrates the important proof of concept of the ability of pyrogallol[4]arene to react with metals in higher oxidation states to assemble into atomically‐precise hexameric coordination cages. As such, these results open up exciting avenues toward the assembly of previously unanticipated metal–organic capsules, for example offering inspiration for tackling metals exhibiting high valence states such as in the lanthanide and actinide series.
An efficient catalyst based on a water‐soluble cobalt(II) complex of S,S′‐bis(2‐pyridylmethyl)‐1,2‐thiobenzene for electrochemical‐ and photochemical‐driven hydrogen evolution
Authors: Xie Zhen‐Lang , Jiang Wen‐Xing , Wang Nan‐Shu , Zhan Shu‐Zhong
Published: December 2019

The reaction of S,S′‐bis(2‐pyridylmethyl)‐1,2‐thiobenzene and CoCl2 affords a water‐soluble cobalt(II) complex, [(bptb)CoCl2], which has been characterized using various methods. Under blue light, together with CdS nanorods as a photosensitizer and ascorbic acid as a sacrificial electron donor, [(bptb)CoCl2] can catalyze hydrogen generation from water and can work for 90 h. Under optimal conditions, this photocatalytic system achieves a turnover number (TON) of 22 900 moles of H2 per mole of catalyst during 60 h of irradiation, and the highest apparent quantum yield is ca 26.63% at 469 nm. Moreover, [(bptb)CoCl2] exhibits much higher activity than [(bpte)CoCl2] (bpte = S,S′‐bis(2‐pyridylmethyl)‐1,2‐thioethane; TON = 6740 moles of H2 per mole of catalyst during 60 h of irradiation), indicating that bptb can constitute a better catalyst for hydrogen production than bpte. This result can be attributed to the electronic properties of the ligands (bptb and bpte). The introduction of phenyl makes the electron distribution more uniform in the cobalt complex, allowing easier formation of the Co(III)–H species, further promoting the formation of hydrogen.
Oxidative dehydrogenation of ethylbenzene to styrene with CO2 over Al‐MCM‐41‐supported vanadia catalysts
Authors: Chen Shuwei , Xu Zheqi , Tan Dongchen , Pan Dahai , Cui Xingyu , Qiao Yan , Li Ruifeng
Published: December 2019

Catalytic performance of Al‐MCM‐41‐supported vanadia catalysts (V/Al‐MCM‐41) with different V loading was investigated for oxidative dehydrogenation of ethylbenzene to styrene (ST) with CO2 (CO2‐ODEB). For comparison, pure silica MCM‐41 was also used as support for vanadia catalyst. The catalysts were characterized by N2 adsorption, X‐ray diffraction (XRD) pyridine‐Fourier‐transform infrared spectroscopy, H2‐temperature‐programmed reduction, thermogravimetric analysis (TGA), UV‐Raman, and diffuse reflectance (DR) UV–vis spectroscopy. The results indicate that the catalytic behavior and the nature of V species depend strongly on the V loading and the support properties. Compared with the MCM‐41‐supported catalyst, the Al‐MCM‐41‐supported vanadia catalyst exhibits much higher catalytic activity and stability along with a high ST selectivity (>98%). The superior catalytic performance of the present V/Al‐MCM‐41 catalyst can be attributed to the Al‐MCM‐41 support being more favorable for the high dispersion of V species and the stabilization of active V5+ species. Together with the characterization results of XRD, TGA, and DR UV–Vis spectroscopy, the deep reduction of V5+ into V3+ during CO2‐ODEB is the main reason for the deactivation of the supported vanadia catalyst, while the coke deposition has a less important impact on the catalyst stability.
Molecular structure development in silsesquioxane−urethane thin film hybrids: A small‐angle neutron scattering investigation
Authors: Knott Robert , Dutta Naba K. , Choudhury Namita Roy
Published: December 2019

The small‐angle neutron scattering (SANS) technique was used to investigate the molecular structurein situof the synthesis of a series of polyhedral oligomeric silsesquioxane (POSS)‐based polyurethane hybrid materials with respect to the reaction time, and the hybridization chemistry. In order to tailor the material properties for application in thin film coatings of metal surfaces, the effect on the hybrid structure was investigated of a selected end‐capping agent (silane[N‐ethyl‐3‐trimethoxysilyl‐2‐methylpropanamine]; A‐Link35) and chain extension agent (poly[ethylene glycol‐ran‐propylene glycol]). The structure of the POSS‐urethane hybrid in solution was observed to vary between fully or partially solvated polymer chains (radius of gyrationRg~20–40 Å), and larger collapsed structures (Rg>100'sÅ). © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2020,137, 48772.
Retentive drug delivery systems based on shape memory materials
Authors: Maroni Alessandra , Melocchi Alice , Zema Lucia , Foppoli Anastasia , Gazzaniga Andrea
Published: December 2019

Retentive drug delivery systems are intended for prolonged residence and release inside hollow organs of the body, in pursuit of either local or systemic therapeutic goals. Because of the relatively long‐lasting period of time they could cover during operation, a primary advantage arising from their use would lie in reduced dosing frequency, thereby improving the overall adherence of patients to prescribed medication regimens. The treatment of numerous pathologies that affect the urinary bladder and the stomach could especially benefit from viability of such delivery technologies. Moreover, by making use of effective gastroretentive dosage forms, the bioavailability of drugs that are preferably absorbed from the upper gastrointestinal tract could be increased. Expansion of devices following administration is often exploited for retention purposes, and several formulation strategies have been proposed in this respect. Innovative applications of shape memory materials have also been explored, highlighting the great inherent potential for facing the challenges involved. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48798.
Surface modification of mesoporous silica by radiation induced graft polymerization of styrene and subsequent sulfonation for ion‐exchange applications
Authors: Khan Ijaz A. , Hussain Hazrat , Yasin Tariq , Inaam‐ul‐Hassan Muhammad
Published: December 2019

In this study, the fabrication of silica‐grafted‐sulfonated styrene (S‐g‐SSt) resin by grafting of styrene onto silanized silica via gamma radiation‐induced polymerization and subsequent sulfonation of the grafted styrene is described. The grafting was strongly affected by the reaction conditions; absorbed dose, monomer concentration, and the type of solvent used. The structural analysis of the silica and all the relevant products were carried out by FTIR, SEM, TGA, XRD, and BET. FTIR analysis confirmed the presence of styrene onto silica and subsequent sulfonation. The BET nitrogen adsorption–desorption isotherms indicated that grafting occurs on the surface as well as inside the pores. Finally, the ion exchange capacity (IEC) of the fabricated S‐g‐SSt was evaluated by ion exchange titrations (back titration method). The IEC was found to be in the range of 0.43–2.97 meq/g depending on the degree of grafting. The facile fabrication method and high IEC value (2.97 meq/g) could lead to potential application of the fabricated S‐g‐SSt resin in ion exchange resin in waste water treatment and metal recovery. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48835.
Decimation of a population of the endangered species Scutellastra mexicana (Broderip and Sowerby, 1829) (Mollusca, Gastropoda) in the Marías Island (Eastern Ocean Pacific) Biosphere Reserve
Authors: Carballo José Luis , Yáñez Benjamín , Bautista‐Guerrero Eric , García‐Gómez José Carlos , Espinosa Free , Tortolero‐Langarica José J.A. , Michel‐Morfín Jesús Emilio
Published: December 2019

Scutellastra mexicana is the largest known patellid limpet species and probably is one of the most endangered marine invertebrates.

The species was once distributed along the American Pacific coast from Mexico to Peru, but their large size (up to 35 cm long) and easy accessibility (shallow sublittoral), made it very vulnerable to human collection and now is extinct on most of the mainland Mexican coast.

In August 2017, a large population of this species was found on María Cleofas island, off the coast of west‐central Mexico (Marías Archipelago, Pacific Ocean). This constitutes the only report of a population of this species since 1988.

A total of 808 adult individuals of up to 26 cm in length and 20 cm in width were estimated, together with the presence of juveniles, suggesting that it is a self‐sustaining population. The population was monitored in August 2017 and August 2018.

Although the species is under the category ‘Special Protection’ in the General Mexican Wild Law, and that María Cleofas island is a Biosphere Reserve, fishermen that operate with impunity in the area decimated the limpet population within a year of its discovery. Abundance in the shallowest area decreased significantly from 120 individuals per transect (65 m long and 2.75 m wide) in August 2017 to 48 individuals in August 2018, and the estimated adult population decreased from 808 to 304 limpets.

Neither passive national conservation policies nor local practices have reduced current threats to biodiversity and resource depletion in Marías Archipelago. Protected areas like this are ‘paper parks’—parks in name only—because there is no active conservation strategy or protection of marine species.
Extreme Anatomy: The Lottery Winners, Specialists, and Extreme Adaptations That Are No More
Authors: Smith Timothy D. , Laitman Jeffrey T.
Published: December 2019

This special issue of The Anatomical Record explores extravagant adaptions that vertebrates have evolved from their base groups to survive in the most challenging environments. It stems from a symposium entitled “Extreme Anatomy: Living beyond the edge,” which was held April 23, 2017, at the annual meeting of the American Association for Anatomy, in Chicago, IL. In Part 1 of this issue, we examined extreme morphologies that allow exploration of new niches. In this issue, we return to the evolution of terrestriality by digging deeply into the fossil history of the piscine antecedent of tetrapods. These were truly “lottery winners” among vertebrates. This issue also bears on extreme specialists that once thrived but are now long extinct and some extant species that thrive in the hottest terrestrial niches. Herein, several contributions discuss developmental strategies that facilitate later demanding locomotor regimens and feeding strategies for accessing nutrients from less than ideal food sources. From mole‐rats to short‐faced breeds of domestic dogs, we encounter another host of the most unusual of earth's creatures, who have much to teach us about our world. Anat Rec, 2019. © 2019 American Association for Anatomy Anat Rec, 303:214–217, 2020. © 2019 American Association for Anatomy
CO Gas‐free Intramolecular Cyclocarbonylation Reactions of Haloarenes Having a C‐Nucleophile through CO‐Relay between Rhodium and Palladium
Authors: Morimoto Tsumoru , Yamashita Mana , Tomiie Ai , Tanimoto Hiroki , Kakiuchi Kiyomi
Published: December 2019

We describe transfer carbonylation reactions of 2‐bromoarenes that contain a carbon‐nucleophile using aldehydes as a substitute for CO, leading to the formation of indanone derivatives. The transformation proceeds efficiently under RhI/Pd0‐hybrid catalytic conditions consisting of two discrete transition metals, rhodium and palladium, which catalyze the decarbonylation of aldehydes and the subsequent carbonylation of bromoarenes using the resulting carbonyl moiety, respectively. The majority of the abstracted CO is transferred directly to the product via a CO‐relay process from rhodium to palladium.
Biochemical Characterization of Homoserine Dehydrogenase from Pseudomonas aeruginosa
Authors: Kim Do Hyeon , Nguyen Quyet Thang , Yang Jin Kuk
Published: December 2019

Homoserine dehydrogenase (HSD) catalyzes the reduction of l‐aspatate‐4‐semaldehyde (l‐ASA) to l‐homoserine (l‐HSE) or oxidation reversely, which is a part of the aspartate pathway synthesizing threonine, isoleucine, and methionine in vivo. HSD has gained much interest in medical application since HSD is a well‐established target for pesticides and antibiotics. In addition, HSD is also valuable in industrial application for l‐lysine production. In this study, HSD from Pseudomonas aeruginosa (PaHSD) was overexpressed in Escherichia coli, and purified to homogeneity for molecular and biochemical characterization. PaHSD exhibits the comparable activity of l‐HSE oxidation for both types of cofactors, NAD+ and NADP+, but at the same time shows interesting differences. The kcat/Km value of NADP+ was ~1.8 times larger than that of NAD+, while the kcat/Km value of l‐HSE was ~1.4 times larger with NAD+ than with NADP+. Notably, the Km value is about three times smaller for NADP+, while Vmax is about 1.7 times larger for NAD+, which implies that while NADP+ binds more strongly to the active site, NAD+ has a faster turnover. Size‐exclusion chromatography analysis showed PaHSD forms tetramers, as opposed to HSDs from other species forming dimers. In the circular dichroism analysis, PaHSD showed a typical spectrum of α/β structure, and its melting temperature was determined to be 50.5 °C from the thermal denaturation test at 222 nm. The molecular and biochemical features of PaHSD revealed in this study provide the basis for the future study of amino acid metabolism, and its application to industrial and medical purposes.
Harnessing single‐stranded DNA binding protein to explore protein–protein and protein–DNA interactions
Authors: Chen Stefanie H. , Goller Carlos C.
Published: December 2019

Proteins must interact with a variety of other cellular components to properly perform their functions. We have developed a series of five experiments based on the robust bacterial single‐stranded DNA binding protein (SSB) to characterize both known and unknown protein–protein and protein–DNA interactions. Students work in groups to generate and process data from electrophoretic mobility shift assays (EMSA), yeast two‐hybrid, far Western, chromatin immunoprecipitation (ChIP), and fluorescence microscopy experiments, including choosing a novel condition for each. A gamification approach was used to encourage student participation and laboratory safety. Student learning was assessed using pre‐ and post‐surveys and course grade data. The results indicate a clear increase in both content knowledge and confidence in the topics presented. Ranking of course activities indicated that performing the hands‐on laboratory exercises was the most valuable course component, and over half of the students would choose to take another course with a similar gamification component. Each of the five laboratory experiments can be performed in combination with each other or integrated separately into a related course, and the gamification structure can be applied to any course.
Influence of different jaw positions on dynamic balance using Y‐balance test
Authors: Zafar Hamayun , Alghadir Ahmad H. , Iqbal Zaheen Ahmed , Iqbal Amir , Anwer Shahnawaz , Alnahdi Ali H.
Published: December 2019

Background

Jaw sensory‐motor system has been shown to affect static balance of the body. It would be interesting to know whether it can influence dynamic balance as well. The objective of this study is to examine the influence of different jaw positions on dynamic balance using the Y‐balance test.

Methods

Eighty healthy male participants aged 20–35 years were invited to participate in this study. Dynamic balance was measured by the Y‐balance test in three directions (anterior, posteromedial, and posterolateral) for each leg separately in three jaw positions: resting jaw (control), open‐jaw, and clenched jaw.

Results

There were no significant differences in reach distances between the different jaw positions except in the posterolateral direction. In comparison with resting jaw position, reach distance was significantly higher in open‐jaw position for the right leg and in clenched and open‐jaw positions for the left leg in the posterolateral direction.

Conclusions

Although various studies have shown direct or indirect influence of jaw sensory‐motor system on static postural control, results of this study point to limited relation with dynamic postural control among healthy subjects. However, it supports the potential of the jaw sensory‐motor system to affect motor control during functional tasks in patients with postural instability or similar disorders.
Sustainability and financial performance of small and medium sized enterprises: A bibliometric and systematic literature review
Authors: Bartolacci Francesca , Caputo Andrea , Soverchia Michela
Published: December 2019

Based on a 20‐year dataset collected from the Web of Science database, this study aims to present a comprehensive knowledge map of the intellectual structure of the field of study of sustainability and financial performances in small and medium sized enterprises (SMEs). A bibliometric analysis and a systematic literature review method were employed by analyzing articles published between 1999 and 2018, using the VOSViewer software. The study provides an overview of articles, authors, the most influential journals, and themes of research. The results reveal the existence of three themes in research: the role of innovation and entrepreneurship and their impact on sustainability in SMEs (cluster 1), corporate social responsibility in the context of SMEs (cluster 2), and green management and environmental issues for SMEs (cluster 3). In sum, this paper discusses prominent insights from the research analyses and recommends future research directions for the field.
Survival of stage II nasopharyngeal carcinoma patients with or without concurrent chemotherapy: A propensity score matching study
Authors: Liu Di‐Han , Zhou Xiao‐Yu , Pan You‐Guang , Chen Si , Ye Zheng‐Hao , Chen Gang‐Dong
Published: December 2019

Background

To ascertain if concurrent chemotherapy (CCT) benefits people with stage II nasopharyngeal carcinoma (NPC) treated with two‐dimensional radiotherapy (2DRT) or intensity‐modulated radiotherapy (IMRT).

Methods

A total of 4157 patients diagnosed with stage II NPC were evaluated. Patients received radiotherapy (RT) with/without CCT. Patients were divided into 2DRT and IMRT subgroups. After propensity score matching, the role of CCT was explored in these two subgroups. Overall survival (OS) was the primary endpoint and progression‐free survival (PFS), locoregional relapse‐free survival (LRFS) and distant metastasis‐free survival (DMFS) were secondary endpoints.

Results

In the 2DRT subgroup, CCT addition to RT benefited cases with T1N1/T2N1 in OS, PFS and LRFS (P < .001, P = .003 and P = .003, respectively) significantly, but no difference was observed in patients with T2N0. DMFS were similar in the two arms. CCT was a significant protective factor for OS, PFS, and LRFS for patients with stage N1. In the IMRT subgroup, RT alone could maintain equivalent OS, PFS, LRFS and DMFS (P = .209, .448, .477 and .602 respectively) and cause less acute toxicity compared with concurrent chemoradiotherapy (CCRT).

Conclusion

CCRT was better than 2DRT alone among patients with T1‐2N1M0 stage. CCT application for NPC patients receiving IMRT led to no survival benefit and greater toxic effects.
Unexpected NADPH Hydratase Activity in the Nitrile Reductase QueF from Escherichia coli
Authors: Jung Jihye , Braun Jan , Czabany Tibor , Nidetzky Bernd
Published: December 2019

The nitrile reductase QueF catalyzes NADPH‐dependent reduction of the nitrile group of preQ0 (7‐cyano‐7‐deazaguanine) into the primary amine of preQ1 (7‐aminomethyl‐7‐deazaguanine), a biologically unique reaction important in bacterial nucleoside biosynthesis. Here we have discovered that the QueF from Escherichia coli—its D197A and E89L variants in particular (apparent kcat≈10−2 min−1)—also catalyze the slow hydration of the C5=C6 double bond of the dihydronicotinamide moiety of NADPH. The enzymatically C6‐hydrated NADPH is a 3.5:1 mixture of R and S forms and rearranges spontaneously through anomeric epimerization (β→α) and cyclization at the tetrahydronicotinamide C6 and the ribosyl O2. NADH and 1‐methyl‐ or 1‐benzyl‐1,4‐dihydronicotinamide are not substrates of the enzymatic hydration. Mutagenesis results support a QueF hydratase mechanism, in which Cys190—the essential catalytic nucleophile for nitrile reduction—acts as the general acid for protonation at the dihydronicotinamide C5 of NADPH. Thus, the NADPH hydration in the presence of QueF bears mechanistic resemblance to the C=C double bond hydration in natural hydratases.
Analyzing the Substrate Specificity of a Class of Long‐Horned‐Beetle‐Derived Xylanases by Using Synthetic Arabinoxylan Oligo‐ and Polysaccharides
Authors: Pauchet Yannick , Ruprecht Colin , Pfrengle Fabian
Published: December 2019

Xylophagous long‐horned beetles thrive in challenging environments. To access nutrients, they secrete plant‐cell‐wall‐degrading enzymes in their gut fluid; among them are cellulases of the subfamily 2 of glycoside hydrolase family 5 (GH5_2). Recently, we discovered that several beetle‐derived GH5_2s use xylan as a substrate instead of cellulose, which is unusual for this family of enzymes. Here, we analyze the substrate specificity of a GH5_2 xylanase from the beetle Apriona japonica (AJAGH5_2‐1) using commercially available substrates and synthetic arabinoxylan oligo‐ and polysaccharides. We demonstrate that AJAGH5_2‐1 processes arabinoxylan polysaccharides in a manner distinct from classical xylanase families such as GH10 and GH11. AJAGH5_2‐1 is active on long oligosaccharides and cleaves at the non‐reducing end of a substituted xylose residue (position +1) only if: 1) three xylose residues are present upstream and downstream of the cleavage site, and 2) xylose residues at positions −1, −2, +2 and +3 are not substituted.
A rare case of pseudotumor cerebri in adult Lyme disease
Authors: Nørreslet Gimsing Louise , Lunde Larsen Line Sofie
Published: December 2019

It is important to recognize the rare manifestations of chronic Lyme disease to prevent permanent disabilities. We present an adult case of chronic Lyme disease, who developed pseudotumor cerebri and who needed supplementary surgical treatment. We compare it to the existing published literature, reviewed by a systematic approach.
Kinetics of Triphase Extractive Oxidative Desulfurization of Benzothiophene with Molecular Oxygen Catalyzed by HPA‐5
Authors: Claußnitzer Johannes , Bertleff Benjamin , Korth Wolfgang , Albert Jakob , Wasserscheid Peter , Jess Andreas
Published: December 2019

The triphasic aerobic extractive desulfurization of benzothiophene (BT) using an aqueous H8[PV5Mo7O40] solution as catalyst and O2 as oxidant was investigated. A time‐resolved analysis of all reaction products in the gas, organic and aqueous phase, is given. The organic sulfur in BT is mainly converted to sulfuric acid. Mass transport limitations can be excluded. The reaction orders are 1 with regard to BT, and 0.5 both for HPA‐5 and O2. Calculated data derived from this mechanism with a power law kinetic approach show good agreement to the experimental data for conversions below 60 %. At higher BT conversions, significant deviations are found, suggesting that acidic products formed in the BT oxidation affect the catalyst and therefore the initial kinetics of the BT oxidation.
Electrochemical‐Induced Ring Transformation of Cyclic α‐(ortho‐Iodophenyl)‐β‐oxoesters
Authors: Strehl Julia , Kahrs Christoph , Müller Thomas , Hilt Gerhard , Christoffers Jens
Published: December 2019

Cyclic α‐(ortho‐iodophenyl)‐β‐oxoesters were converted in a ring‐expanding transformation to furnish benzannulated cycloalkanone carboxylic esters. The reaction sequence started by electrochemical reduction of the iodoarene moiety. In a mechanistic rationale, the resulting carbanionic species was adding to the carbonyl group under formation of a strained, tricyclic benzocyclobutene intermediate, which underwent carbon–carbon bond cleavage and rearrangement of the carbon skeleton by retro‐aldol reaction. The scope of the reaction sequence was investigated by converting cyclic oxoesters with different ring sizes yielding benzocycloheptanone, ‐nonanone and ‐decanone derivatives in moderate to good yields. Furthermore, acyclic starting materials and cyclic compounds carrying additional substituents on the iodophenyl ring were submitted to this reaction sequence. The starting materials for this transformation are straightforwardly obtained by conversion of β‐oxoesters with phenyliodobis(trifluoroacetate).
Millistructured Reactor as Tool for Investigating the Kinetics of Maleic Anhydride Synthesis
Authors: Müller Mauritio , Junge Kira , Mestl Gerhard , Turek Thomas
Published: December 2019

A nearly isothermal millistructured fixed‐bed reactor was used to investigate the kinetics of the selective oxidation of n‐butane to maleic anhydride. In addition to the investigation of a broad range of industrially relevant conditions, the focus was on the influence of the reaction products on the kinetics. For this purpose, a saturator for the accurate dosing of the target product MA was developed. The experimental data were used to derive a reaction network comprising the by‐products acetic and acrylic acid. Additionally, the inhibition of the associated reactions by reactants and products was investigated.
An Efficient, Robust New Scheme for Establishing Broadband Homonuclear Correlations in Biomolecular Solid State NMR
Authors: Wi Sungsool , Frydman Lucio
Published: December 2019

An efficient mixing scheme is introduced for establishing two‐dimensional (2D) homonuclear correlations based on dipolar couplings. This mixing scheme achieves broadband dipolar recoupling using remarkably low powers even under ultrafast magic‐angle spinning (MAS) rates. This Adiabatic Linearly FREquency Swept reCOupling (AL FRESCO) method applies a series of weak frequency‐chirped pluses on the 1H channel, for performing efficient 13C−13C magnetization transfers leading to cross peaks between sites separated over small or large chemical shift differences. The mixing scheme is nearly free from dipolar truncation effects, and thanks to the low RF powers it involves it can act over long mixing times (≥1.5 sec). Key considerations required for optimizing this chirped pulse mixing scheme are discussed, and the new kind of correlations that can emerge from this method are demonstrated using uniformly 13C‐labeled Barstar as test protein sample.
Elimination of Yellow Phase: An Effective Method to Achieve High Quality HC(NH2)2PbI3‐based Perovskite Films
Authors: Xu Xiaoxiao , Zheng Haiying , Liu Guozhen , Zhu Liangzheng , He Dingchao , Xu Shendong , Xu Huifen , Zhang Liying , Zhang Xianxi , Pan Xu
Published: December 2019

Formamidinium lead iodide‐based (FAPbI3) perovskite is widely used in the field of photovoltaics, owing to its suitable bandgap (ca. 1.45 eV) and better thermal stability. FAPbI3 has two polymorphs (black α‐FAPbI3 and yellow δ‐FAPbI3) at ambient temperature. The yellow δ‐FAPbI3, which has no photoactivity, has a chain‐like structure that likely hinders electron transport and reduces photovoltaic performance. However, pure‐phase black α‐FAPbI3 without any yellow phase is difficult to obtain and the underlying mechanism of the phase transition is rarely investigated. In this study, a facile bi‐additive method (BA method) has been developed to completely eliminate the yellow δ‐FAPbI3 phase by inducing a phase transition from δ‐FAPbI3 to α‐FAPbI3. HI and Pb(SCN)2 were employed as dual additives. Based on the investigation of the annealing time and temperature, we determined that the BA method can induce the phase transition and enhance the stability of α‐FAPbI3. Owing to the enhanced crystallization as well as uniform morphology of the BA film, the perovskite solar cells (PSCs) exhibited an increased power conversion efficiency (PCE). Furthermore, the optimal devices displayed excellent stability and maintained over 80 % of initial PCE after aging for 400 h in air. This work provides a new insight into the fabrication of high‐quality pure α‐FAPbI3 perovskite films and makes high efficiency photovoltaic devices a reality.
The impact of local population genetic background on the spread of the selfish element Medea‐1 in red flour beetles
Authors: Cash Sarah A. , Robert Michael A. , Lorenzen Marcé D. , Gould Fred
Published: December 2019

Selfish genetic elements have been found in the genomes of many species, yet our understanding of their evolutionary dynamics is only partially understood. A number of distinct selfish Medea elements are naturally present in many populations of the red flour beetle (Tribolium castaneum). Although these Medea elements are predicted by models to increase in frequency within populations because any offspring of a Medea‐bearing mother that do not inherit at least one Medea allele will die, experiments demonstrating an increase in a naturally occurring Medea element are lacking. Our survey of the specific Medea element, M1, in the United States showed that it had a patchy geographic distribution. From the survey, it could not be determined if this distribution was caused by a slow process of M1 colonization of discrete populations or if some populations lacked M1 because they had genetic factors conferring resistance to the Medea mechanism. We show that populations with naturally low to intermediate M1 frequencies likely represent transient states during the process of Medea spread. Furthermore, we find no evidence that genetic factors are excluding M1 from US populations where the element is not presently found. We also show how a known suppressor of Medea can impair the increase of M1 in populations and discuss the implications of our findings for pest‐management applications of Medea elements.