bluuebunny/crossref_metadata_2025 huggingface dataset:
Interface and Defect Engineering for Metal Halide Perovskite Optoelectronic Devices
Authors: Han Tae‐Hee , Tan Shaun , Xue Jingjing , Meng Lei , Lee Jin‐Wook , Yang Yang
Published: February 2019

Metal halide perovskites have been in the limelight in recent years due to their enormous potential for use in optoelectronic devices, owing to their unique combination of properties, such as high absorption coefficient, long charge‐carrier diffusion lengths, and high defect tolerance. Perovskite‐based solar cells and light‐emitting diodes (LEDs) have achieved remarkable breakthroughs in a comparatively short amount of time. As of writing, a certified power conversion efficiency of 22.7% and an external quantum efficiency of over 10% have been achieved for perovskite solar cells and LEDs, respectively. Interfaces and defects have a critical influence on the properties and operational stability of metal halide perovskite optoelectronic devices. Therefore, interface and defect engineering are crucial to control the behavior of the charge carriers and to grow high quality, defect‐free perovskite crystals. Herein, a comprehensive review of various strategies that attempt to modify the interfacial characteristics, control the crystal growth, and understand the defect physics in metal halide perovskites, for both solar cell and LED applications, is presented. Lastly, based on the latest advances and breakthroughs, perspectives and possible directions forward in a bid to transcend what has already been achieved in this vast field of metal halide perovskite optoelectronic devices are discussed.
Recent Progress of Singlet‐Exciton‐Harvesting Fluorescent Organic Light‐Emitting Diodes by Energy Transfer Processes
Authors: Byeon Sung Yong , Lee Dong Ryun , Yook Kyoung Soo , Lee Jun Yeob
Published: February 2019

The external quantum efficiency (EQE) of organic light‐emitting diodes (OLEDs) has been dramatically improved by developing highly efficient organic emitters such as phosphorescent emitters and thermally activated delayed fluorescent (TADF) emitters. However, high‐EQE OLED technologies suffer from relatively poor device lifetimes in spite of their high EQEs. In particular, the short lifetimes of blue phosphorescent and TADF OLEDs remain a big hurdle to overcome. Therefore, the high‐EQE approach harvesting singlet excitons of fluorescent emitters by energy transfer processes from the host or sensitizer has been explored as an alternative for high‐EQE OLED strategies. Recently, there has been a big jump in the EQE and device lifetime of singlet‐exciton‐harvesting fluorescent OLEDs. Recent progress on the materials and device structure is discussed herein.
Tumor Microenvironment‐Activatable Prodrug Vesicles for Nanoenabled Cancer Chemoimmunotherapy Combining Immunogenic Cell Death Induction and CD47 Blockade
Authors: Zhou Fangyuan , Feng Bing , Yu Haijun , Wang Dangge , Wang Tingting , Ma Yuting , Wang Siling , Li Yaping
Published: February 2019

Chemoimmunotherapy is reported to activate a robust T cell antitumor immune response by triggering immunogenic cell death (ICD), which has initiated a number of clinical trials. However, current chemoimmunotherapy is restricted to a small fraction of patients due to low drug delivery efficacy and immunosuppression within the tumor microenvironment. A tumor microenvironment‐activatable prodrug vesicle for cancer chemoimmunotherapy using ICD is herein reported. The prodrug vesicles are engineered by integrating an oxaliplatin (OXA) prodrug and PEGylated photosensitizer (PS) into a single nanoplatform, which show tumor‐specific accumulation, activation, and deep penetration in response to the tumoral acidic and enzymatic microenvironment. It is demonstrated that codelivery of OXA prodrug and PS can trigger ICD of the tumor cells by immunogenic cells killing. The combination of prodrug vesicle‐induced ICD with Î ± CD47‐mediated CD47 blockade further facilitates dendritic cell (DC) maturation, promotes antigen presentation by DCs, and eventually propagates the antitumor immunity of ICD. CD47 blockade and ICD induction efficiently inhibit the growth of both primary and abscopal tumors, suppress tumor metastasis, and prevent tumor recurrence. Collectively, these results imply that boosting antitumor immunity using ICD induction and suppressing tumor immune evasion via CD47 blockade might be promising for improved cancer chemoimmunotherapy.
NIR Biosensing of Neurotransmitters in Stem Cell‐Derived Neural Interface Using Advanced Core–Shell Upconversion Nanoparticles
Authors: Rabie Hudifah , Zhang Yixiao , Pasquale Nicholas , Lagos Maureen J. , Batson Philip E. , Lee Ki‐Bum
Published: February 2019

Nondestructive neurotransmitter detection and real‐time monitoring of stem cell differentiation are both of great significance in the field of neurodegenerative disease and regenerative medicine. Although luminescent biosensing nanoprobes have been developed to address this need, they have intrinsic limitations such as autofluorescence, scattering, and phototoxicity. Upconversion nanoparticles (UCNPs) have gained increasing attention for various biomedical applications due to their high photostability, low auto‐fluorescent background, and deep tissue penetration; however, UCNPs also suffer from low emission intensities due to undesirable energy migration pathways. To address the aforementioned issue, a single‐crystal core–shell–shell “sandwich” structured UCNP is developed that is designed to minimize deleterious energy back‐transfer to yield bright visible emissions using low power density excitations. These UCNPs show a remarkable enhancement of luminescent output relative to conventional β‐NaYF4:Yb,Er codoped UCNPs and β‐NaYF4:Yb,Er@NaYF4:Yb “active shell” alike. Moreover, this advanced core–shell–shell UCNP is subsequently used to develop a highly sensitive biosensor for the ultrasensitive detection of dopamine released from stem cell‐derived dopaminergic‐neurons. Given the challenges of in situ detection of neurotransmitters, the developed NIR‐based biosensing of neurotransmitters in stem cell‐derived neural interfaces present a unique tool for investigating single‐cell mechanisms associated with dopamine, or other neurotransmitters, and their roles in neurological processes.
Pulsed Laser Modulated Shock Transition from Liquid Metal Nanoparticles to Mechanically and Thermally Robust Solid–Liquid Patterns
Authors: Deng Biwei , Cheng Gary J.
Published: February 2019

In this work, a general mechanism is discovered to form liquid‐metal‐based, stable and stretchable conductive patterns on rigid and soft substrates. It is discovered that pulsed laser irradiation of liquid metal nanoparticles (LMNPs) with tunable conditions can induce transformation to stable and stretchable solid–liquid (S–L) dual phases on various surfaces. Formation of this unique solid–liquid composite phase is the key to change the wetting behavior of the conductive patterns on various substrates and enables mechanically stable patterns on various substrates. Pulsed‐laser‐driven thermo‐mechanical shock momentum is important for rupture and joining of the LMNPs, providing much better control than the traditional mechanical sintering. The solid nanophase forms a nanoporous matrix filled with and wetted by the LM, thereby providing a stabilization mechanism for the S–L composite patterned thin film. The mechanical and thermal reliability of the solid–liquid patterns is investigated. The S–L patterns can stretch up to 30% strain and cycle stably for 7000 cycles. It can be heated up to 177 °C with an input power of 0.58 W. The solid–liquid composite film provides great opportunity for various applications as a flexible conductor with unique mechanical and physics properties and further inspires design of LM devices for completely exposed applications.
Improved Charge Extraction Beyond Diffusion Length by Layer‐by‐Layer Multistacking Intercalation of Graphene Layers inside Quantum Dots Films
Authors: Chen Wenjun , Castro Joshua , Ahn Seungbae , Li Xiaochen , Vazquez‐Mena Oscar
Published: February 2019

Charge collection is critical in any photodetector or photovoltaic device. Novel materials such as quantum dots (QDs) have extraordinary light absorption properties, but their poor mobility and short diffusion length limit efficient charge collection using conventional top/bottom contacts. In this work, a novel architecture based on multiple intercalated chemical vapor deposition graphene monolayers distributed in an orderly manner inside a QD film is studied. The intercalated graphene layers ensure that at any point in the absorbing material, photocarriers will be efficiently collected and transported. The devices with intercalated graphene layers have superior quantum efficiency over single‐bottom graphene/QD devices, overcoming the known restriction that the diffusion length imposes on film thickness. QD film with increased thickness shows efficient charge collection over the entire λ ≈ 500–1000 nm spectrum. This architecture could be applied to boost the performance of other low‐cost materials with poor mobility, allowing efficient collection for films thicker than their diffusion length.
Strong Surface Bonding of Polysulfides by Teflonized Carbon Matrix for Enhanced Performance in Room Temperature Sodium‐Sulfur Battery
Authors: Vijaya Kumar Saroja Ajay Piriya , Muthusamy Kamaraj , Sundara Ramaprabhu
Published: February 2019

The practical application of room temperature sodium‐sulfur (Na–S) battery remains far away from the market due to the poor coulombic efficiency and cyclic stability which in turn arises from high dissolution of intermediate polysulfides in carbonate‐based electrolytes, slow reaction kinetics, and low electrical conductivity of sulfur. In this aspect, an advanced cathode structure by incorporating Teflon‐lined conductive carbon substrate (TCS) as a supporting cathode to efficiently immobilize the migration of soluble polysulfides to the anode, as well as enhance the conductivity during the polysulfide conversion, is presented here. After inclusion of TCS, the cell delivers a specific capacity of 800 mAh g−1 at 0.1C (1C = 1672 mA g−1) with 85% enhancement in specific capacity. Also, a stable cyclic stability of about 300 cycles with an excellent capacity retention of about 93% and coulombic efficiency of nearly 100% is obtained. Teflon, which has a linear carbon chain surrounded completely by fluorine atoms, acts as the anchoring sites for trapping the intermediate sodium polysulfides. This study provides a simple approach of controlling the shuttling effect, which can be beneficial for the development of high energy density room temperature Na–S battery.
2D SnO/In2O3 van der Waals Heterostructure Photodetector Based on Printed Oxide Skin of Liquid Metals
Authors: Alsaif Manal M. Y. A. , Kuriakose Sruthi , Walia Sumeet , Syed Nitu , Jannat Azmira , Zhang Bao Yue , Haque Farjana , Mohiuddin Md , Alkathiri Turki , Pillai Naresh , Daeneke Torben , Ou Jian Zhen , Zavabeti Ali
Published: February 2019

Heterostructures assembled from atomically thin materials have led to a new paradigm in the development of the next‐generation high‐performing functional devices. However, the construction of the ultrathin van der Waals (vdW) heterostructures is challenging and/or limited to materials with layered crystal structures. Herein, liquid metal vdW transfer method is used to construct large area heterostructures of atomically thin metal oxides of p‐SnO/n‐In2O3 with ease. The heterostructure exhibits both outstanding photodetectivity of 5 × 109 Jones and photoresponsivity of 1047 A W−1 with fast response time of ≤1 ms under illumination of the 280 nm light. Such excellent performances are due to the formation of the narrow bandgap of the staggered gap at the p–n junction produced by the high‐quality SnO/In2O3 heterostructure. The facile production of high‐quality vdW heterostructures using the liquid metal–based method therefore provides a promising pathway for realizing future optoelectronic devices.
Adsorption and Exchangeability of Fibronectin and Serum Albumin Protein Corona on Annealed Polyelectrolyte Multilayers and Their Consequences on Cell Adhesion
Authors: Muzzio Nicolas E. , Pasquale Miguel A. , Rios Xabier , Azzaroni Omar , Llop Jordi , Moya Sergio E.
Published: February 2019

Polyelectrolyte multilayers (PEMs) based on biopolyelectrolytes are highly appealing for the surface engineering of biomaterials and the tuning of cell response and phenotypes for biomedical applications. However, cell adhesion is limited on biopolyelectrolyte PEMs. Thermal annealing provides a simple means to increase or decrease cell adhesion on PEMs. The work presented here aims to understand cellular interactions with annealed PEMs based on the adsorption and exchangeability of two model proteins: fibronectin (FN), an adhesion protein, and bovine serum albumin (BSA), a nonadhesion protein. Protein adsorption and exchangeability are studied on annealed poly‐l‐lysine (PLL)/sodium alginate (Alg) and chitosan (Chi)/hyaluronic acid (HA) PEMs using [131I] radiolabeled proteins and gamma counting. Upon annealing cell adhesion is enhanced on PLL/Alg multilayers and decreased on Chi/HA multilayers. For PLL/Alg PEMs, annealing increases adsorption of both FN and BSA and reduces exchangeability. For Chi/HA multilayers, annealing increases BSA adsorption but decreases FN deposition, accompanied by a greater exchangeability. Changes in topographic features of deposited proteins on annealed PLL/Alg hint on changes in the 3D structure of the proteins. Circular dichroism shows that FN retains a large β‐sheet contribution upon adsorption to both annealed and unannealed PLL/Alg PEMs, also suggesting changes in tertiary structure.
Chitooligosaccharide Biguanide Repairs Islet β‐Cell Dysfunction by Activating the IRS‐2/PI3K/Akt Signaling Pathway in Type 2 Diabetic Rats
Authors: Zou Yalu , Wang Yuanyuan , Zhang Shengsheng , Wu Yuntang , Liu Xiaofei
Published: February 2019

Islet β cell failure is a critical metabolic disorder in the development of type 2 diabetes (T2DM), and the decreased viability and dysfunction of β cells accelerate diabetic pathogenesis in association with higher mortality. In this study, the therapeutic effects of chitooligosaccharide biguanide (COSG), which is similar in structure to metformin and has negligible side effects, on islet β‐cell dysfunction and the possible mechanism are explored. Streptozocin‐induced diabetic rats are administered COSG via daily intragastric gavage for 8 weeks. COSG significantly controlled body weight loss, attenuated glucose levels in blood and urine, and increased serum insulin. Histological examination of the pancreas reveals that COSG also alleviated pancreatic atrophy in T2DM rats. Furthermore, COSG stimulated insulin receptor substrate‐2 (IRS‐2) signaling in rat islet β cells, thereby mediating the activation of the phosphatidylinositol 3 kinase/protein kinase (PI3K/Akt) signaling pathway. In addition, COSG promoted downstream forkhead transcription factor O1 (FoxO1) nuclear output to potentially activate pancreas duodenum homeobox‐1 (PDX‐1)/glucose transporter type‐2 (GLUT‐2)/glucose kinase (GCK) pathway‐regulated insulin secretion. COSG also inhibited the glycogen synthase kinase‐3β (GSK‐3β)/caspase‐3 pathway to prevent cell apoptosis. The intrinsic protective effects of COSG on the impaired insulin signaling system to delay β‐cell apoptosis, increase β‐cell growth and proliferation, improve β‐cell function and promote insulin secretion highlight the possibilities of COSG as a novel strategy for the prevention of T2DM.
Transport Properties of Topological Semimetal Tungsten Carbide in the 2D Limit
Authors: Wang Cheng , Chen Long , Liu Zhen , Liu Zhibo , Ma Xiu‐Liang , Xu Chuan , Cheng Hui‐Ming , Ren Wencai , Kang Ning
Published: February 2019

Recent theoretical calculations and spectroscopy measurements have shown that several materials with the tungsten carbide‐type structure, such as molybdenum phosphide and tungsten carbide (WC), are a new type of topological semimetal hosting triply degenerate nodal points. So far, most of experimental studies are performed on large‐size bulk crystal. 2D nanostructures, with large surface‐to‐volume ratio, are expected to provide an attractive system for probing topological surface states and the development of device applications. Here the transport characterization of high‐quality ultrathin WC single crystals is reported. The magnetoresistance (MR) shows a strong anisotropic behavior, which may be attributed to the transport anomalies of three‐component fermions as theoretically proposed. The scaling analysis reveals the presence of the surface states in WC. The observation of the nonsaturating MR in strong magnetic fields, together with nonlinear and strong temperature dependent Hall effect, is consistent with the proposed multiple bands character of carriers in WC. In addition, a low‐temperature upturn in the resistance is observed, indicating that electron–electron interaction plays a prominent role in charge transport. The results demonstrate that the ultrathin WC crystals offer a potential platform for exploring exotic transport properties arising from the three‐component fermions in the 2D limit.
Atomic Fe‐Doped MOF‐Derived Carbon Polyhedrons with High Active‐Center Density and Ultra‐High Performance toward PEM Fuel Cells
Authors: Deng Yijie , Chi Bin , Li Jing , Wang Guanghua , Zheng Long , Shi Xiudong , Cui Zhiming , Du Li , Liao Shijun , Zang Ketao , Luo Jun , Hu Yongfeng , Sun Xueliang
Published: February 2019

A metalorganic gaseous doping approach for constructing nitrogen‐doped carbon polyhedron catalysts embedded with single Fe atoms is reported. The resulting catalysts are characterized using scanning transmission electron microscopy, X‐ray photoelectron spectroscopy, and X‐ray absorption spectroscopy; for the optimal sample, calculated densities of Fe–Nx sites and active N sites reach 1.75812 × 1013 and 1.93693 × 1014 sites cm‐2, respectively. Its oxygen reduction reaction half‐wave potential (0.864 V) is 50 mV higher than that of 20 wt% Pt/C catalyst in an alkaline medium and comparable to the latter (0.78 V vs 0.84 V) in an acidic medium, along with outstanding durability. More importantly, when used as a hydrogen–oxygen polymer electrolyte membrane fuel cell (PEMFC) cathode catalyst with a catalyst loading as low as 1 mg cm‐2 (compared with a conventional loading of 4 mg cm‐2), it exhibits a current density of 1100 mA cm‐2 at 0.6 V and 637 mA cm‐2 at 0.7 V, with a power density of 775 mW cm‐2, or 0.775 kW g–1 of catalyst. In a hydrogen–air PEMFC, current density reaches 650 mA cm‐2 at 0.6 V and 350 mA cm‐2 at 0.7 V, and the maximum power density is 463 mW cm‐2, which makes it a promising candidate for cathode catalyst toward high‐performance PEMFCs.
Molecular Level Insight into Enhanced n‐Type Transport in Solution‐Printed Hybrid Thermoelectrics
Authors: Zaia Edmond W. , Gordon Madeleine P. , Niemann Valerie , Choi Jaeyoo , Chatterjee Ruchira , Hsu Chih‐Hao , Yano Junko , Russ Boris , Sahu Ayaskanta , Urban Jeffrey J.
Published: February 2019

Perylene diimide (PDI) derivatives hold great promise as stable, solution‐printable n‐type organic thermoelectric materials, but as of yet lack sufficient electrical conductivity to warrant further development. Hybrid PDI‐inorganic nanomaterials have the potential to leverage these physical advantages while simultaneously achieving higher thermoelectric performance. However, lack of molecular level insight precludes design of high performing PDI‐based hybrid thermoelectrics. Herein, the first explicit crystal structure of these materials is reported, providing previously inaccessible insight into the relationship between their structure and thermoelectric properties. Allowing this molecular level insight to drive novel methodologies, simple solution‐based techniques to prepare PDI hybrid thermoelectric inks with up to 20‐fold enhancement in thermoelectric power factor over the pristine molecule (up to 17.5 µW mK−2) is presented. This improved transport is associated with reorganization of organic molecules on the surface of inorganic nanostructures. Additionally, outstanding mechanical flexibility is demonstrated by fabricating solution‐printed thermoelectric modules with innovative folded geometries. This work provides the first direct evidence that packing/organization of organic molecules on inorganic nanosurfaces is the key to effective thermoelectric transport in nanohybrid systems.
Rarity does not limit genetic variation or preclude subpopulation structure in the geographically restricted desert forb Astragalus lentiginosus var. piscinensis
Authors: Harrison Joshua G. , Forister Matthew L. , Mcknight Stephanie R. , Nordin Erin , Parchman Thomas L.
Published: February 2019

Premise of the Study

Characteristics of rare taxa include small population sizes and limited geographical ranges. The genetic consequences of rarity are poorly understood for most taxa. A small geographical range could result in reduced opportunity for isolation by distance or environment, thereby limiting genetic structure and variation, but few studies explore genetic structure at small spatial scales with sufficient resolution to test this hypothesis. Moreover, few comparative genetic studies exist among infrataxa differing in rarity. Here, we compare genetic variation among varieties of Astragalus lentiginosus differing in range size. Additionally, we ask if genetic structure exists in A. lentiginosus var. piscinensis, a rare taxon consisting of several thousand individuals that persist on ~8 km2 of alkaline soil.

Methods

We compared genetic variation among 11 varieties of A. lentiginosus differing in range size using a genotyping by sequencing (GBS) approach, which generated 11,475 single nucleotide polymorphisms (SNPs). We characterized genetic structure among subpopulations of A. lentiginosus var. piscinensis using a second GBS data set of 7274 SNPs and explored associations between genetic structure and environmental variation.

Key Results

We found no association between genetic variation and range size among varieties of A. lentiginosus. Additionally, despite the extremely small range of A. lentiginosus var. piscinensis, we report a well‐defined genetic structure among subpopulations associated with microhabitat variation in soil composition.

Conclusions

Our results suggest that fine scale genetic structure may exist within other rare Astragalus taxa and that rarity does not preclude the maintenance of genetic diversity in this genus.
Convergent Synthesis of Linear and Branched β(1,3)‐Glucans and Evaluation of their Binding Affinities to Dectin‐1
Authors: Hamagami Hiroki , Adachi Yoshiyuki , Ohno Naohito , Tanaka Hiroshi
Published: February 2019

β(1,3)‐Glucans, major components of fungal and bacterial cell‐walls, activate innate immunity by binding to dectin‐1 on immune cells. This paper describes a convergent synthesis of linear and multi‐branched β(1,3)‐glucan oligosaccharides for the study of structure‐activity relationships between β(1,3)‐glucans and their binding affinities to dectin‐1. The synthetic strategy highlights regioselective gold‐catalyzed glycosylations in the preparation of β(1,3)‐glucosides, as well as an efficient multiple glycosylation for the incorporation of several β(1,6)‐glucosides into β(1,3)‐glucosides. Based on this strategy, linear undecasaccharides and branched tetradecasaccharides, which had a partial structure of curdlan and schizophyllan, respectively, were successfully synthesized. Competitive inhibition experiments of these synthetic oligosaccharides revealed that the presence of an amino group at the reducing end was required for their binding to dectin‐1, whereas β(1,6)‐glucosides did not improve their binding affinities to dectin‐1.
Merging Photochemistry with Electrochemistry: Functional‐Group Tolerant Electrochemical Amination of C(sp3)−H Bonds
Authors: Wang Fei , Stahl Shannon S.
Published: February 2019

Direct amination of C(sp3)−H bonds is of broad interest in the realm of C−H functionalization because of the prevalence of nitrogen heterocycles and amines in pharmaceuticals and natural products. Reported here is a combined electrochemical/photochemical method for dehydrogenative C(sp3)−H/N−H coupling that exhibits good reactivity with both sp2 and sp3 N−H bonds. The results show how use of iodide as an electrochemical mediator, in combination with light‐induced cleavage of intermediate N−I bonds, enables the electrochemical process to proceed at low electrode potentials. This approach significantly improves the functional‐group compatibility of electrochemical C−H amination, for example, tolerating electron‐rich aromatic groups that undergo deleterious side reactions in the presence of high electrode potentials.
On‐Surface Synthesis of Ethynylene‐Bridged Anthracene Polymers
Authors: Sánchez‐Grande Ana , de la Torre Bruno , Santos José , Cirera Borja , Lauwaet Koen , Chutora Taras , Edalatmanesh Shayan , Mutombo Pingo , Rosen Johanna , Zbořil Radek , Miranda Rodolfo , Björk Jonas , Jelínek Pavel , Martín Nazario , Écija David
Published: February 2019

Engineering low‐band‐gap π‐conjugated polymers is a growing area in basic and applied research. The main synthetic challenge lies in the solubility of the starting materials, which precludes advancements in the field. Here, we report an on‐surface synthesis protocol to overcome such difficulties and produce poly(p‐anthracene ethynylene) molecular wires on Au(111). To this aim, a quinoid anthracene precursor with =CBr2 moieties is deposited and annealed to 400 K, resulting in anthracene‐based polymers. High‐resolution nc‐AFM measurements confirm the nature of the ethynylene‐bridge bond between the anthracene moieties. Theoretical simulations illustrate the mechanism of the chemical reaction, highlighting three major steps: dehalogenation, diffusion of surface‐stabilized carbenes, and homocoupling, which enables the formation of an ethynylene bridge. Our results introduce a novel chemical protocol to design π‐conjugated polymers based on oligoacene precursors and pave new avenues for advancing the emerging field of on‐surface synthesis.
The Structure of an Archaeal B‐Family DNA Polymerase in Complex with a Chemically Modified Nucleotide
Authors: Kropp Heike M. , Diederichs Kay , Marx Andreas
Published: February 2019

Archaeal B‐family DNA polymerases (DNA pols) are the driving force of cutting‐edge biotechnological applications like next‐generation sequencing. The acceptance of chemically modified nucleotides by DNA pols is key to these technologies. Until now, no structural data have been available for these DNA pols in complex with modified substrates, which could build the basis for understanding interactions between the enzyme and the chemically modified nucleotide and for the further development of next‐generation nucleotides. For the first time, we crystallized an exonuclease‐deficient variant of the wild‐type B‐family KOD DNA pol with a modified nucleotide in a closed, ternary complex. We also crystalized the A‐family DNA pol KlenTaq with the same nucleotide. The reported structural data reveal how the protein and the DNA modulate two distinct conformations of the appended moiety in the A‐ and B‐family DNA pols and how these influence the processing of the modified nucleotide. Overall, this study provides first insight into the interplay between B‐family DNA pols and relevant modified substrates.
Mechanical properties of continuous bamboo fiber‐reinforced biobased polyamide 11 composites
Authors: Haddou Geoffrey , Dandurand Jany , Dantras Eric , Maiduc Huynh , Thai Hoang , Giang Nguyen Vu , Trung Tran Huu , Ponteins Philippe , Lacabanne Colette
Published: February 2019

This study is devoted to the analysis of the properties of continuous bamboo fiber (BF)‐reinforced polyamide 11 (PA 11) composites. The SEM observations highlighted continuity between BFs and the polymeric matrix showing a high density of hydrogen bonds. The comparative calorimetric study of the matrix and its composites showed that the crystallinity of PA 11 was not modified by the presence of bamboo fibers. The physical aging observed in PA 11 is no more observed in composites due to physical interactions between PA 11 and BFs. The mechanical properties were investigated by tensile strength and dynamic mechanical analysis. The introduction of BFs enhanced Young's modulus of the matrix by a factor of 10. The presence of BFs also improved the storage shear modulus G′ over the whole temperature range. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47623.
Synthesis of Cyclopenta‐HBCs and their Regioselective Chlorination During Oxidative Cyclodehydrogenation
Authors: Hall Thomas B. J. , Hoggard Bryce R. , Larsen Christopher B. , Lucas Nigel T.
Published: February 2019

Hexa‐peri‐hexabenzocoronenes with a bay‐fused five‐membered ring are synthesized from fluorenyl precursors. The key oxidative cyclodehydrogenation step is accompanied by regioselective chlorination that is enhanced by methylation at the cyclopenta‐ring or increased reaction concentration. The CpHBC products undergo mild electrophilic aromatic bromination, without catalyst, to afford adducts suitable for π‐extension by cross‐coupling.
High dose vitamin D supplementation is associated with an improvement in serum markers of liver function
Authors: Tavakoli Hamidreza , Rostami Hossein , Avan Amir , Bagherniya Mohammad , Ferns Gordon A. , Khayyatzadeh Sayyed Saeid , Ghayour‐Mobarhan Majid
Published: February 2019

Limited studies have examined the effects of vitamin D on liver enzymes in patients with liver disease but none has explored its effects in the healthy subjects. The aim of present study was to evaluate the effects of a high dose vitamin D supplementation on measures of liver function. A total of 988 adolescent girls were recruited; all were assessed for liver function tests (LFTs) including alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), gamma‐glutamyl transferase (ϒGT), alkaline phosphatase (ALP), total bilirubin, direct bilirubin, albumin, and total protein before and after supplementation with 50,000 IU cholecalciferol perls. Significant reductions were observed for AST, ALT, direct bilirubin, total bilirubin, LDH, and ϒGT at the end of supplementation, only in the group with abnormal reference value. Serum levels of total protein and albumin were higher at the end of follow up in the group with abnormal value. No significant change was obtained for LFTs in the group with normal value. Our findings suggest that vitamin D supplementation may improve markers of liver function in adolescents with abnormal LFTs. More randomized controlled trial with longer follow‐up time will be required. © 2019 BioFactors, 45(3):335–342, 2019
Major hepatectomy with or without pancreatoduodenectomy for advanced gallbladder cancer
Authors: Mizuno T , Ebata T , Yokoyama Y , Igami T , Yamaguchi J , Onoe S , Watanabe N , Ando M , Nagino M
Published: February 2019

Background

The indications for major hepatectomy for gallbladder cancer either with or without pancreatoduodenectomy remain controversial. The clinical value of these extended procedures was evaluated in this study.

Methods

Patients who underwent major hepatectomy for gallbladder cancer between 1996 and 2016 were identified from a prospectively compiled database. Postoperative outcomes and overall survival were compared between patients undergoing major hepatectomy alone or combined with pancreatoduodenectomy (HPD).

Results

Seventy-nine patients underwent major hepatectomy alone and 38 patients had HPD. The patients who underwent HPD were more likely to have T4 disease (P < 0·001), nodal metastasis (P = 0·015) and periaortic nodal metastasis (P = 0·006), but were less likely to receive adjuvant therapy (P = 0·006). HPD was associated with a high incidence of grade III or higher complications (P = 0·002) and death (P = 0·037). Overall survival was longer in patients who underwent major hepatectomy alone than in patients who underwent HPD (median survival time 32 versus 10 months; P < 0·001). In multivariable analysis, surgery in the early period (1996–2006) (P = 0·002), pathological T4 disease (P = 0·005) and distant metastasis (P < 0·001) were associated with shorter overall survival, and cystic duct tumour (P = 0·002) with longer overall survival.

Conclusion

Major hepatectomy alone for gallbladder cancer contributes to favourable overall survival with low morbidity and mortality, whereas HPD is associated with poor overall survival and high morbidity and mortality rates. HPD may eradicate locally spreading gallbladder cancer; however, the indication for the procedure is questioned from an oncological viewpoint.
Analysis of Raman Spectral Characteristics of Chemical Warfare Agents by Using 248‐nm UV Raman Spectroscopy
Authors: Choi Sun‐Kyung , Jeong Young‐Su , Koh Young Jin , Lee Jae Hwan , Nam Hyun‐Woo , Lee Juno
Published: February 2019

Chemical warfare agents (CWAs) are extremely toxic and fatal to humans. It is required to quickly identify the released chemical agents and warn against the CWAs for protecting human life. The primary CWA contamination due to attacks occurs mostly on the ground surface, and Raman spectroscopy can quickly identify CWA on the surface in a non‐contact manner. In particular, the interference can be reduced by avoiding the fluorescence of materials on the surface while increasing the Raman‐scattering intensity with the excitation light source of deep ultra violet (UV) smaller than 250 nm. In this study, the Raman spectra of 18 chemical agents, including major CWAs, were measured using a Raman spectroscopy system with 248‐nm deep‐UV light source, and the spectral characteristics of each agent were analyzed. From the results, we confirmed that deep‐UV Raman spectroscopy could be the main method for quickly and accurately detecting and identifying CWA contamination.
Periostin plays role in force‐induced stem cell potential by periodontal ligament stem cells
Authors: Panchamanon Panita , Pavasant Prasit , Leethanakul Chidchanok
Published: February 2019

Mechanical stimuli have been shown to play an important role in directing stem cell fate and maintenance of tissue homeostasis. One of the functions of the mechanoresponsive tissue periodontal ligament (PDL) is to withstand the functional forces within the oral cavity. Periodontal ligament stem cells (PDLSCs) derived from periodontal tissue have been demonstrated to be able to respond directly to mechanical forces. However, the mechanisms of action of mechanical force on PDLSCs are not totally understood. The aim of this study was to investigate the mechanisms by which compressive force affects PDLSCs, especially their stemness properties. PDLSCs were established from extracted human third molars; their stem cell characteristics were validated by detecting the expression of stem cell markers and confirming their ability to differentiate into osteogenic and adipogenic lineages. PDLSCs were subjected to various magnitudes of static compressive force (0 [control], 0.5, 1.0, 1.5, or 2 g/cm2). Application of 1.0 g/cm2 compressive force significantly upregulated a panel of stem cell marker genes, including NANOG and OCT4. Conversely, higher force magnitudes downregulated these genes. Mechanical loading also upregulated periostin, a matrix protein that plays important roles in tissue morphogenesis. Interestingly, knockdown of periostin using siRNA abolished force‐induced stem cell marker expression in PDLSCs. This study suggests a proper magnitude of compressive force could be one important factor involved in the modulation of the pluripotency of PDLSCs through the action of periostin. The precise mechanism by which periostin regulates stemness requires further detailed investigation.
A QoS‐aware energy‐efficient memetic flower pollination routing protocol for underwater acoustic sensor network
Authors: Sivakumar V. , Rekha D.
Published: February 2019

Huge number of applications ranging from commercial, scientific, to military applications are recently emerging in Underwater Acoustic Sensor Networks (UWASNs). The major research challenges associated with UWASN includes high energy consumption, large propagation delay, and low available bandwidth due to its acoustic medium. In this paper, Quality of Service (QoS)–aware Energy‐Efficient Memetic Flower Pollination Routing (MFPR) has been proposed to identify optimal energy‐efficient routing coverage set in underwater. The fitness function for MFP is formulated for Vector‐Based Forward (VBF) protocol that allocates the reliable routing path for source node within its routing pipe. The proposed algorithm works in two stages, where Memetic algorithm is responsible for identifying the optimal route cover set and FPA is responsible for switching between local and global pollination to forward packets in reliable path. In addition, the proposed work considers Grant Free Pattern Division Multiple Access (GFPDMA) packets for routing purpose, since it reduces the latency at the time of packet transmission. Hence, this forms QoS‐aware routing in UWASN. The proposed MFPR is evaluated in UWASN environment that runs applications with varied QoS requirements. The simulation result shows that the novel proposed method improves the performance of UWASN in terms of high network lifetime, less end‐to‐end delay, high energy consumption, high packet delivery ratio, and high throughput than existing Quality‐of‐Service–Aware Evolutionary Routing Protocol (QERP) and Balanced and Multi‐objective Optimized Opportunistic Routing (BMOOR) models.
Enhancing CO2 Electroreduction with Au/Pyridine/Carbon Nanotubes Hybrid Structures
Authors: Ma Zhongqiao , Lian Cheng , Niu Dongfang , Shi Lei , Hu Shuozhen , Zhang Xinsheng , Liu Honglai
Published: February 2019

Selective electrochemical reduction of CO2 by using renewable electricity has received considerable attention because of the potential to convert a harmful greenhouse gas into useful chemicals. A high‐performance electrocatalyst for CO2 reduction is constructed based on metal nanoparticles/organic molecule hybrid materials. On the nanoscale, Au nanoparticles are uniformly anchored on carbon nanotubes to afford substantially increased current density, improved selectivity for CO, and enhanced stability. On the molecular level, the catalytic performance is further enhanced by introducing axial pyridine groups to the surface of the carbon nanotubes. The resulting hybrid catalyst exhibits around 93 % faradaic efficiency for CO production over a wide potential range (−0.58 to −0.98 V), a high mass activity of 251 A gAu−1 at −0.98 V in aqueous solution at near‐neutral pH, and strong stability with continuous electrolysis for 10 h at −0.58 V. DFT calculations indicate that the synergistic effects of Au and axial pyridine could dramatically stabilize the key intermediate (*COOH) formed in the rate‐limiting step of CO2 reduction, which effectively lowers the overpotential.
Ilexgenin A inhibits mitochondrial fission and promote Drp1 degradation by Nrf2‐induced PSMB5 in endothelial cells
Authors: Zhu Yingchao , Li Ming , Lu Yawen , Li Jun , Ke Ye , Yang Jie
Published: February 2019

Atherosclerosis (AS) is one of important events involving in the pathological process of coronary artery disease. Many traditional Chinese medicines have been widely used for the treatment of AS. Previous studies have demonstrated that Ilexgenin A (IA) obtained from Ilex hainanensis Merr. could improve AS development. However, its underlying mechanism is still unknown. This study was conducted to explore the possible targets and mechanisms involving in the anti‐atheroclerosis effect of IA. The results showed IA significantly promoted NO production, reduced reactive oxygen species (ROS) generation, and inflammatory cytokine production induced by palmitate (PA) in endothelial cells, demonstrating IA could improve endothelial dysfunction. Meanwhile, IA dramatically inhibited dynamin‐related protein 1 (Drp1) expression and mitochondrial fission induced by PA whereas proteasome inhibitor epoxomicin attenuated its effect on Drp1 expression, indicating IA decreased Drp1 expression with regulation of proteasome. Furthermore, IA also could increase the expression of proteasome subunit beta type5 (PSMB5) and activate nuclear factor‐like 2 (Nrf2). Nrf2 knockdown eliminated the induction effect of IA on PSMB5 expression while abrogated its inhibition on ROS generation and mitochondrial fission stimulated by PA. These results demonstrated that IA could promote PSMB5 expression in an Nrf2‐dependent manner, resulting in the suppression of mitochondrial fission, and thus improve endothelial dysfunction. These findings laid a foundation to the future development of IA as an agent to the prevention and treatment of AS.
The speciation history of northern‐ and southern‐sourced Eranthis (Ranunculaceae) species on the Korean peninsula and surrounding areas
Authors: Oh Ami , Oh Byoung‐Un
Published: February 2019

The temporal and spatial origins and evolution of the genus Eranthis have not been previously studied. We investigated the speciation and establishment histories of four Eranthis species: Eranthis byunsanensis, E. pungdoensis, E. stellata, and E. pinnatifida. The sampling localities were Korea, Japan, Jilin in China, and the area near Vladivostok in Primorskiy, Russia. We used 12 chloroplast microsatellite loci (n = 935 individuals) and two chloroplast noncoding regions (rpl16 intron, petL‐psbE intergenic spacer; n = 33 individuals). The genetic diversity, genetic structure, phylogenetic relationships of the four species were analyzed, and their ancestral areas were reconstructed. The high genetic diversity of the Jeju island population of E. byunsanensis and Russian populations of E. stellata indicated these species’ northward and southward dispersal, respectively. The genetic structure analyses suggest that the populations in these four species have limited geographical structure, except for the Chinese E. stellata population (SCP). The phylogenetic analyses suggest that E. byunsanensis and E. pinnatifida are sister species and that Chinese SCP may not belong to E. stellata. The ancestral area reconstruction revealed that the most recent common ancestor of the four species existed in the current Chinese habitat of E. stellata. This study shows that E. byunsanensis and E. pinnatifida originated from a southern Eranthis species and speciated into their current forms near Jeju island and near western regions of Japan, respectively, during the Miocene. E. stellata may have dispersed southward on and near the Korean peninsula, though its specific origin remains unclear. Interestingly, the Chinese E. stellata population SCP suggests that the Chinese population might be most ancient among all the four Eranthis species. E. pungdoensis may have allopatrically speciated from E. byunsanensis during the Holocene. The Korean peninsula and the surrounding areas can be considered interesting regions which provide the opportunity to observe both northern‐ and southern‐sourced Eranthis species.
The Bromine‐Rich Bromido Metallates [BMIm]2[SnBr6]·(Br2) and [MnBr(18‐crown‐6)]4[SnBr6]2·(Br2)4.5
Authors: Eich Andreas , Köppe Ralf , Roesky Peter W. , Feldmann Claus
Published: February 2019

The bromine‐rich bromido metallates [BMIm]2[SnBr6]·(Br2) (1) and [MnBr(18‐crown‐6)]4[SnBr6]2·(Br2)4.5 (2) were prepared by the reaction of MgBr2 or MnBr2 with SnBr4, 18‐crown‐6, and elemental bromine in the ionic liquids [BMIm][N(Tf)2] and [MeBu3N][N(Tf)2] {BMIm: butyl methyl imidazolium, N(Tf)2: bis(trifluoromethylsulfonyl)amide}. This sequence of reactions was motivated by previous studies in the system ZnBr2/Br2/18‐crown‐6 and here expanded to divalent cations of comparable diameter (i.e., Zn2+ with 74 pm, Mg2+ with 65 pm; Mn2+ with 91 pm). In difference to Zn2+, however, totally different compounds and structures were obtained. [BMIm]2[SnBr6]·(Br2) contains zigzag chains of [SnBr6]2– anions and Br2 that are separated by [BMIm]+ cations. In [MnBr(18‐crown‐6)]4[SnBr6]2·(Br2)4.5 dibromine molecules are interconnected by [MnBr(18‐crown‐6)]+ cations to form two‐dimensional bromine layers. Thermogravimetry shows a remarkably high temperature of 250 °C for Br2 release. The Br–Br interactions were analyzed by Raman spectra and quantum chemical calculations, resulting in a reliable assignment of the observed vibrations and a calculation of the force constants.
Specific N‐demethylation of verapamil by cytochrome P450 from Streptomyces griseus ATCC 13273
Authors: Shen Chen , Liu Hanqing , Dai Wenling , Liu Xiufeng , Liu Jihua , Yu Boyang
Published: February 2019

Norverapamil, the N‐demethylated derivative of verapamil, is a novel promising leading compound for attenuating multidrug resistance with less side effects compared with verapamil. However, the efficient synthetic method for norverapamil is absent. In this study, an innovative biotechnological method based on enzymatic catalysis was presented for the high‐efficient production of norverapamil. CYP105D1, a cytochrome P450 from Streptomyces griseus ATCC 13273, was identified to carry out a one‐step specific N‐demethylation of verapamil along with putidaredoxin reductase (Pdr) and putidaredoxin (Pdx) as the redox partner. Docking calculations rationalized the specific N‐demethylation observed in experiment and identified important amino acid residues for verapamil binding. Furthermore, a CYP105D1‐based whole‐cell system in E. coli BL21(DE3) was established and optimized for highly efficient N‐demethylation of verapamil. The bioconversion rate of verapamil by the whole cell system came up to 60.16% within 24 hours under the optimized conditions. These results demonstrated the high potential of CYP105D1‐based biocatalytic system for norverapamil production.
Prediction: The U.S. will continue to lose international student market share
Authors: Dennis Marguerite J.
Published: February 2019

According to the Institute for International Education, the United States has led the world in the number of enrolled international students since records have been compiled. But as the world order changes, I predict that colleges and universities in the United States will continue to lose market share of the international mobile student and may, in the next few years, release its place as the number one importer of international students.
Power line communications (PLC) technology: More than 20 years of intense research
Authors: Ndjiongue A.R. , Ferreira H.C.
Published: February 2019

After more than two decades since intensive research began on power line communications (PLC) technology, this interesting field of telecommunication engineering is still progressing towards maturity. Despite some factors that delay its worldwide acceptance, its implementation is starting to take off. Research in PLC is motivated (i) by many factors such as the crowded radio frequency spectrum that requires to be sustained by alternative technologies and (ii) by the emanation of other new technologies that may help PLC to extend its practical implementation such as visible light communications or other wireless communication technologies like near‐field communications. PLC technology is used in applications requiring both low and high data rate but traditionally exploited in applications in which the node does not move. Nowadays, PLC has become widely accepted; hence, a review of the technology may be useful to keep the readers aware of new updates. In this paper, we provide an overview of the evolution of PLC technology over the last few decades.