bluuebunny/crossref_metadata_2025 huggingface dataset:
Transcriptional and post‐transcriptional suppression of P450IIC11 and P450IIC12 by inflammation
Authors: Wright K. , Morgan E.T.
Published: July 2002

Induction of inflammation in rats by treatment with endotoxin or turpentine is known to suppress levels of hepatic mRNAs for P450IIC11 and P450IIC12. We report that transcription of CYP2C12 in female rats is not significantly reduced from control levels; suppression of this gene during inflammation appears to be mediated post‐transcriptionally. In contrast, transcription of CYP2C11 in male rats is reduced to 23% and to 5% of control levels by turpentine and by endotoxin, respectively. Sex‐specificity of CYP2C11 expression is also regulated transcriptionally, whereas sex‐specificity of CYP2C12 expression appears to be regulated by a post‐transcriptional mechanism.
EGF stimulates the processing and export of a secreted form of EGF receptor
Authors: Khire Jayant , Das Manjusri
Published: July 2002

Human A431 cells express a 100 kDa EGF‐receptor homolog that contains only the external domain. The kinetics of its maturation and export are slow and comparable to those of the transmembrane receptor. Here we demonstrate that exogenously added EGF stimulates post‐translational processing and export of this receptor through a pathway that is insensitive to inhibitors of protein synthesis. The results suggest that EGF may influence one or more of the rate determining steps that control receptor export from endoplasmic reticulum. This may constitute one of the path‐ways by which EGP regulates the expression of its receptor.
Stable rightward shifts of the oxyhemoglobin dissocation curve induced by encapsulation of inositol hexaphosphate in red blood cells using electroporation
Authors: Mouneimne Youssef , Barhoumi Roula , Myers Tim , Slogoff Stephen , Nicolau Claude
Published: July 2002

Rightward shifts of 50–100% of the P
50 values in the oxygen dissociation curve of intracellular hemoglobin are obtained after encapsulation of inositol hexaphosphate in mouse and dog red blood cells (RBC) by electroporation. Life spans of mouse RBC‐myo‐inositol hexaphosphate in circulation are unchanged from the normal RBC values.
Protein phosphatase 2A reverses inhibiton of inward rectifying K+ currents by thyrotropin‐releasing hormone in GH3 pituitary cells
Authors: Barros Francisco , Mieskes Gottfried , del Camino Donato , de la Peña Pilar
Published: July 2002

Thyrotropin‐releasing hormone (TRH) reduces an inwardly rectifying K+ current in whole‐cell voltage‐clamped GH3 rat anterior pituitary cells. The TRH effect depends on the maintenance of a background level of Ca2+ in the pipette buffer, and is rapidly minimized by the intracellular dialysis produced under whole‐cell conditions. Introduction of ADP‐NH‐P, a non‐hydrolizable ATP analog, in the pipettes, nearly abolishes the TRH‐evoked inhibition. The TRH‐induced reduction of the inwardly rectifying current is significantly enhanced by incubation of cells 2–4 h with cholera toxin, but not by inclusion of 1 mM cyclic AMP in the pipettes. Under control whole‐cell conditions, the reduction caused by TRH is not reversed upon washout of the neuropeptide. However, this effect is readily reversed by addition of purified catalytic subunits of protein phosphatase 2A (PP‐2Ac) but not PP‐1c to the buffer used to fill the patch pipettes. Among previous results with PP inhibitors, these data indicate that PP2A is involved in the phosphorylation/dephosphorylation mechanism(s) that regulate the delayed TRH effects on GH3 cell excitability.
Psychosocial factors and chronic illness in childhood
Authors: Zimmermann Tansella C
Published: July 2002

Chronic illness in a child requires successful organisational and emotional adjustment of the child and the family. The way in which the child and the family adapt to the illness will affect their psychological well-being and their quality of life. This review summarizes recent research findings on the relationship between illness factors, individual and family functioning, coping strategies and psychosocial adjustment. The findings are presented within the framework of three complementary theoretical models: the family developmental approach; the psychosocial typology of illnesses; and the process model of stress and coping. These models are useful for a better understanding of the complex interactions between illness, family and coping and offer to the professionals engaged in the care of chronically sick children, guidelines for assessment and the development of intervention programs. The review starts with examining the impact of chronic illness on the psychosocial adjustment of the sick child, his/her siblings and parents. Then psychosocial Stressors and risk factors in terms of illness and family related characteristics are discussed. Coping resources and strategies are presented which have been shown to be related to child and parental adjustment; and finally, successful intervention programs are described.
Lack of association between cholesterol blood levels and platelet serotonin uptake
Authors: Modai I , Valevski A , Kikinzon L , Jerushalmy Z , Weizman A
Published: July 2002

It has been suggested that low serum cholesterol interferes with brain serotonergic functioning, which results in increased suicidal and aggressive tendencies. To test this hypothesis we investigated the relationship between serum cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL) and triglyceride levels, and serotonin uptake by blood platelets in 17 healthy men aged 39.5 ± 10.2 years. Platelet serotonin uptake and serum lipids were assayed concomitantly for each individual. Serum cholesterol levels and other serum lipid levels did not correlate with serotonin uptake by platelets at the concentration of 2 × 10−5 M (a concentration within the maximal uptake capacity range). The results indicate no influence of cholesterol on serotonin uptake, as opposed to some investigators who suggested that high risk of suicide and aggressiveness in hypocholesterolemic individuals is related to impaired serotonin transport.
Studies on a new series of THA analogues: Effects of the aromatic residues that line the gorge of AChE
Authors: Pomponi Massimo , Marta Maurizio , Colella Annalisa , Sacchi Silvia , Patamia Maria , Gatta Franco , Capone Francesca , Oliverio Alberto , Pavone Flaminia
Published: July 2002

A series of N‐monoalkylsubstituted 1,2,3,4‐tetrahydro‐9‐aminoacridines have been prepared after modelling simulation of the AChE–inhibitor complex. Molecular modelling has predicted a number of hydrophobic residues to be involved in the catalytic mechanism of this interaction between the binding sites of AChE and this series of aminoacridines. In these compounds the acridine moiety becomes sandwiched between the rings of PHE330 and TRP84. In particular, the alkyl chain shows the important role of aromatic groups as binding sites. Their in vitro inhibitory properties (enzyme from Electrophorus electricus) confirm the aromatic groups as a general and significant characteristic of the mechanism of AChE inhibition.
Alternatively spliced forms of the cGMP‐gated channel in human keratinocytes
Authors: Oda Yuko , Timpe Leslie C , McKenzie Roderick C , Sauder Daniel N , Largman Corey , Mauro Theodora
Published: July 2002

Alternatively spliced forms of the α subunit of the cGMP‐gated channel have been cloned from human keratinocytes. One form encodes a complete channel which is almost identical to the rod photoreceptor. A second spliced variant would encode a protein missing a portion of the intracellular hydrophilic domain and the putative first transmembrane domain. Both complete and spliced variants of the channel also were found in epidermis. The expression of the complete form of the channel was induced by levels of extracellular calcium which promote keratinocyte differentiation. The cGMP‐gated channel may play an important role in calcium induced keratinocyte differentiation by mediating Ca2+ entry.
Characterization of the internal promoter of human T‐cell leukemia virus type I
Authors: Ariumi Yasuo , Shimotohno Kunitada , Noda Makoto , Hatanaka Masakazu
Published: July 2002

The HTLV‐I provirus contains two different promoters: the classical retroviral promoter in the 5′ long terminal repeat (LTR) and our previously identified second promoter in the pol gene just upstream of the ATG codon of the tax gene. Here, we demonstrated that the internal promoter expresses the gene for Tax but not Rex. As the deletion of upstream of the transcriptional initiation site (nt 5130) caused down‐regulation of the promoter activity, we termed the region HTLV‐I internal regulatory element (HIRE). We found a cellular sequence‐specific DNA binding protein which binds to HIRE. Furthermore, we demonstrated that the 3′LTR regulates Tax expression from the internal promoter. These findings may shed light on a novel mechanism for gene expression in complex retroviruses of the HTLV family.
The participation of pyridine nucleotides redox state and reactive oxygen in the fatty acid‐induced permeability transition in rat liver mitochondria
Authors: Catisti Rosana , Vercesi Anibal E
Published: July 2002

The ability of low concentrations (5–15 μM) of long‐chain fatty acids to open the permeability transition pore (PTP) in Ca2+‐loaded mitochondria has been ascribed to their protonophoric effect mediated by mitochondrial anion carriers, as well as to a direct interaction with the pore assembly [M.R. Wieckowski and L. Wojtczak, FEBS Lett. 423 (1998) 339–342]. Here, we have compared the PTP opening ability of arachidonic acid (AA) with that of carbonyl cyanide‐p‐trifluoromethoxyphenylhydrazone (FCCP) at concentrations that cause similar quantitative dissipation of the membrane potential (ΔΨ) in Ca2+‐loaded rat liver mitochondria respiring on succinate. The initial protonophoric effects of AA and FCCP were only slightly modified by carboxyatractyloside and were followed by PTP opening, as indicated by a second phase of ΔΨ disruption sensitive to EGTA, ADP, dithiothreitol and cyclosporin A. This second phase of ΔΨ dissipation could also be prevented by rotenone or NAD(P)H‐linked substrates which decrease the pyridine nucleotide (PN) oxidation that follows the stimulation of oxygen consumption induced by AA or FCCP. These results suggest that, under the experimental conditions used here, the PTP opening induced by AA or FCCP was a consequence of PN oxidation. Exogenous catalase also inhibited both AA‐ and FCCP‐induced PTP opening. These results indicate that a condition of oxidative stress associated with the oxidized state of PN underlies membrane protein thiol oxidation and PTP opening.
The effects of tgf‐β1 on chick embryo retina development in vitro
Authors: Calvaruso G. , Gerbino E. , Lauricella M. , Tesoriere G.
Published: July 2002

This paper studies the effect exerted by TGF‐β1 on the development of chick embryo retina cultured in vitro. The addition of TGF‐β1 to retinal explants inhibited DNA synthesis, measured as 3H‐thymidine incorporation into trichloroacetic acid‐insoluble fraction, while it increased both wet weight and protein content, in particular that of extracellular matrix proteins. Lastly, in explants treated with TGF‐β1 an increment in the level of fibronectin was demonstrated by means of Western blotting analysis.
LncRNA AATBC regulates Pinin to promote metastasis in nasopharyngeal carcinoma
Authors: Tang Ting , Yang Liting , Cao Yujian , Wang Maonan , Zhang Shanshan , Gong Zhaojian , Xiong Fang , He Yi , Zhou Yujuan , Liao Qianjin , Xiang Bo , Zhou Ming , Guo Can , Li Xiaoling , Li Yong , Xiong Wei , Li Guiyuan , Zeng Zhaoyang
Published: May 2020

Long noncoding RNA (lncRNA) have emerged as crucial regulators for a myriad of biological processes, and perturbations in their cellular expression levels have often been associated with cancer pathogenesis. In this study, we identified AATBC (apoptosis‐associated transcript in bladder cancer, LOC284837) as a novel lncRNA. AATBC was found to be highly expressed in nasopharyngeal carcinoma (NPC), and increased AATBC expression was associated with poor survival in patients with NPC. Furthermore, AATBC promoted migration and invasion of NPC cells in vitro, as well as metastasis in vivo. AATBC upregulated the expression of the desmosome‐associated protein pinin (PNN) through miR‐1237‐3p sponging. In turn, PNN interacted with the epithelial–mesenchymal transition (EMT) activator ZEB1 and upregulated ZEB1 expression to promote EMT in NPC cells. Collectively, our results indicate that AATBC promotes NPC progression through the miR‐1237‐3p–PNN–ZEB1 axis. Our findings indicate AATBC as a potential prognostic biomarker or therapeutic target in NPC.
The cycle of violence as a function of PTSD and appetitive aggression: A longitudinal study with Burundian soldiers
Authors: Nandi Corina , Crombach Anselm , Elbert Thomas , Bambonye Manassé , Pryss Rüdiger , Schobel Johannes , Weierstall‐Pust Roland
Published: May 2020

During deployment, soldiers face situations in which they are not only exposed to violence but also have to perpetrate it themselves. This study investigates the role of soldiers' levels of posttraumatic stress disorder (PTSD) symptoms and appetitive aggression, that is, a lust for violence, for their engaging in violence during deployment. Furthermore, factors during deployment influencing the level of PTSD symptoms and appetitive aggression after deployment were examined for a better comprehension of the maintenance of violence. Semi‐structured interviews were conducted with 468 Burundian soldiers before and after a 1‐year deployment to Somalia. To predict violent acts during deployment (perideployment) as well as appetitive aggression and PTSD symptom severity after deployment (postdeployment), structural equation modeling was utilized. Results showed that the number of violent acts perideployment was predicted by the level of appetitive aggression and by the severity of PTSD hyperarousal symptoms predeployment. In addition to its association with the predeployment level, appetitive aggression postdeployment was predicted by violent acts and trauma exposure perideployment as well as positively associated with unit support. PTSD symptom severity postdeployment was predicted by the severity of PTSD avoidance symptoms predeployment and trauma exposure perideployment, and negatively associated with unit support. This prospective study reveals the importance of appetitive aggression and PTSD hyperarousal symptoms for the engagement in violent acts during deployment, while simultaneously demonstrating how these phenomena may develop in mutually reinforcing cycles in a war setting.
Fast Rate and Long Life Potassium‐Ion Based Dual‐Ion Battery through 3D Porous Organic Negative Electrode
Authors: Yu Ao , Pan Qingguang , Zhang Miao , Xie Donghao , Tang Yongbing
Published: May 2020

Potassium‐based dual ion batteries (K‐DIBs) with potassium cation (K+) intercalation graphitic anodes have been investigated for their potential in large‐scale energy storage applications owing to their merits of low cost and environmental friendly. Nonetheless, graphite anodes are plagued by volume expansion from the large K+ ions and the co‐intercalation of solvent molecules during the charging. Accordingly, organic materials stand out for the flexible adjustable structures and abundant active sites, which can accommodate cations by multiple functional groups without structural collapse. However, K‐DIBs based on organic anodes have rarely been investigated. Herein, 3D porous dipotassium terephthalate nanosheets are synthesized via a freeze‐dry method as the K‐DIB anode, which can reversibly store K+ ions at a fast rate with a high specific capacity and robust stability due to the sufficient redox active sites and diffusion pathways of K+ ions in the 3D porous structure. Consequently, a novel K‐DIB configuration combining this fast kinetics organic anode and environmental friendly expanded graphite (EG) cathode is constructed (pK2TP//EG), which exhibits a high specific capacity (68 mAh g‐1 at 2 C), good rate performance up to 20 C, and long cycling life with a capacity retention ~100% after 2000 cycles, which is the best performance observed among reported K‐DIBs.
Densified Metallic MoS2/Graphene Enabling Fast Potassium‐Ion Storage with Superior Gravimetric and Volumetric Capacities
Authors: Yao Kai , Xu Zhanwei , Ma Meng , Li Jiayin , Lu Fanyu , Huang Jianfeng
Published: May 2020

The potassium‐ion battery (PIB) is an attractive energy storage device that possesses the potential advantages of high energy density and low cost. Herein, a pure 1T‐MoS2 is synthesized on graphene oxide and assembled into a hydrogel. The hydrogel is further tightened to a compact 1T‐MoS2/graphene (CTMG) bulk by a densifying strategy of capillary tension. When employed as an anode for PIBs, the CTMG electrode can store K+ through reversible intercalation and conversion electrochemistry, accompanied with fast kinetics since the 1T‐MoS2 induces a pseudocapacitive storage mechanism and the extraordinary K+ transportation ability. Consequently, the CTMG electrode delivers the high and reversible rate capacities of 511 and 327 mAh g‐1 at 0.1 and 1 A g‐1, respectively. Moreover, the compact architecture reduces the electrode thickness by ≈33% enabling a high volumetric capacity (512 mAh cm‐3 at 0.1 A g‐1 after 100 cycles), as well as holding a promising application in thick electrode.
Multifunctional Bio‐Nanocomposite Coatings for Perishable Fruits
Authors: Jung Seohui , Cui Yufei , Barnes Morgan , Satam Chinmay , Zhang Shenxiang , Chowdhury Reaz A. , Adumbumkulath Aparna , Sahin Onur , Miller Corwin , Sajadi Seyed M. , Sassi Lucas M. , Ji Yue , Bennett Matthew R. , Yu Miao , Friguglietti Jefferson , Merchant Fatima A. , Verduzco Rafael , Roy Soumyabrata , Vajtai Robert , Meredith J. Carson , Youngblood Jeffrey P. , Koratkar Nikhil , Rahman Muhammad M. , Ajayan Pulickel M.
Published: May 2020

Hunger and chronic undernourishment impact over 800 million people, which translates to ≈10.7% of the world's population. While countries are increasingly making efforts to reduce poverty and hunger by pursuing sustainable energy and agricultural practices, a third of the food produced around the globe still is wasted and never consumed. Reducing food shortages is vital in this effort and is often addressed by the development of genetically modified produce or chemical additives and inedible coatings, which create additional health and environmental concerns. Herein, a multifunctional bio‐nanocomposite comprised largely of egg‐derived polymers and cellulose nanomaterials as a conformal coating onto fresh produce that slows down food decay by retarding ripening, dehydration, and microbial invasion is reported. The coating is edible, washable, and made from readily available inexpensive or waste materials, which makes it a promising economic alternative to commercially available fruit coatings and a solution to combat food wastage that is rampant in the world.
Anisotropy of Charge Transport in a Uniaxially Aligned Fused Electron‐Deficient Polymer Processed by Solution Shear Coating
Authors: Xiao Mingfei , Kang Boseok , Lee Seon Baek , Perdigão Luís M. A. , Luci Alex , Warr Daniel A. , Senanayak Satyaprasad P. , Nikolka Mark , Statz Martin , Wu Yutian , Sadhanala Aditya , Schott Sam , Carey Remington , Wang Qijing , Lee Mijung , Kim Chaewon , Onwubiko Ada , Jellett Cameron , Liao Hailiang , Yue Wan , Cho Kilwon , Costantini Giovanni , McCulloch Iain , Sirringhaus Henning
Published: May 2020

Precise control of the microstructure in organic semiconductors (OSCs) is essential for developing high‐performance organic electronic devices. Here, a comprehensive charge transport characterization of two recently reported rigid‐rod conjugated polymers that do not contain single bonds in the main chain is reported. It is demonstrated that the molecular design of the polymer makes it possible to achieve an extended linear backbone structure, which can be directly visualized by high‐resolution scanning tunneling microscopy (STM). The rigid structure of the polymers allows the formation of thin films with uniaxially aligned polymer chains by using a simple one‐step solution‐shear/bar coating technique. These aligned films show a high optical anisotropy with a dichroic ratio of up to a factor of 6. Transport measurements performed using top‐gate bottom‐contact field‐effect transistors exhibit a high saturation electron mobility of 0.2 cm2 V−1 s−1 along the alignment direction, which is more than six times higher than the value reported in the previous work. This work demonstrates that this new class of polymers is able to achieve mobility values comparable to state‐of‐the‐art n‐type polymers and identifies an effective processing strategy for this class of rigid‐rod polymer system to optimize their charge transport properties.
High Phase Stability in CsPbI3 Enabled by Pb–I Octahedra Anchors for Efficient Inorganic Perovskite Photovoltaics
Authors: Wang Yong , Chen Gaoyuan , Ouyang Dan , He Xinjun , Li Can , Ma Ruiman , Yin Wan‐Jian , Choy Wallace C. H.
Published: May 2020

CsPbI3 inorganic perovskite has exhibited some special properties particularly crystal structure distortion and quantum confinement effect, yet the poor phase stability of CsPbI3 severely hinders its applications. Herein, the nature of the photoactive CsPbI3 phase transition from the perspective of PbI6 octahedra is revealed. A facile method is also developed to stabilize the photoactive phase and to reduce the defect density of CsPbI3. CsPbI3 is decorated with multifunctional 4‐aminobenzoic acid (ABA), and steric neostigmine bromide (NGBr) is subsequently used to further mediate the thin films' surface (NGBr‐CsPbI3(ABA)). The ABA or NG cation adsorbed onto the grain boundaries/surface of CsPbI3 anchors the PbI6 octahedra via increasing the energy barriers of octahedral rotation, which maintains the continuous array of corner‐sharing PbI6 octahedra and kinetically stabilizes the photoactive phase CsPbI3. Moreover, the added ABA and NGBr not only interact with shallow‐ or deep‐level defects in CsPbI3 to significantly reduce defect density, but also lead to improved energy‐level alignment at the interfaces between the CsPbI3 and the charge transport layers. Finally, the champion NGBr‐CsPbI3(ABA)‐based inorganic perovskite solar cell delivers 18.27% efficiency with excellent stability. Overall, this work demonstrates a promising concept to achieve highly phase‐stabilized inorganic perovskite with suppressed defect density for promoting its optoelectronic applications.
Direct Evidence of Graphene‐Induced Molecular Reorientation in Polymer Films
Authors: Carr Amanda J. , Head Ashley , Boscoboinik Jorge Anibal , Bhatia Surita R. , Eisaman Matthew D.
Published: May 2020

For the first time, direct evidence of graphene‐induced molecular reorientation in polymer films using polarization modulated infrared reflection absorption spectroscopy (PM‐IRRAS) is presented. By creating favorable electrostatic interactions, graphene–polymer interfaces can be controlled by varying polymer and solvent composition. After transfer of unmodified graphene from copper onto a polymer substrate, polymer chain rearrangement relative to the orientation at the polymer‐copper interfaces is observed using PM‐IRRAS. Transfer success is characterized using both optical transmission measurements and Raman spectroscopy to quantify the transfer fidelity, that is, graphene coverage fraction. Taken together, oxygen‐containing poly(ethylene‐co‐vinyl acetate) shows more polymer chain rearrangement and better graphene coverage compared to oxygen‐free polyethylene. Polymer composition seems to dominate graphene–polymer interactions while solvent choice has a smaller effect on transfer quality. These results are the first direct measurement of this effect and point toward the possibility of engineering graphene–polymer interactions for specific applications.
Ion‐Selective Sensors Based on Laser‐Induced Graphene for Evaluating Human Hydration Levels Using Urine Samples
Authors: Kucherenko Ivan S. , Sanborn Delaney , Chen Bolin , Garland Nate , Serhan Michael , Forzani Erica , Gomes Carmen , Claussen Jonathan C.
Published: May 2020

Complex graphene electrode fabrication protocols including conventional chemical vapor deposition and graphene transfer techniques as well as more recent solution‐phase printing and postprint annealing methods have hindered the wide‐scale implementation of electrochemical devices including solid‐state ion‐selective electrodes (ISEs). Herein, a facile graphene ISE fabrication technique that utilizes laser induced graphene (LIG), formed by converting polyimide into graphene by a CO2 laser and functionalization with ammonium ion (NH4+) and potassium ion (K+) ion‐selective membranes, is demonstrated. The electrochemical LIG ISEs exhibit a wide sensing range (0.1 × 10−3–150 × 10−3 m for NH4+ and 0.3 × 10−3–150 × 10−3 m for K+) with high stability (minimal drop in signal after 3 months of storage) across a wide pH range (3.5–9.0). The LIG ISEs are also able to monitor the concentrations of NH4+ and K+ in urine samples (29–51% and 17–61% increase for the younger and older patient; respectively, after dehydration induction), which correlate well with conventional hydration status measurements. Hence, these results demonstrate a facile method to perform in‐field ion sensing and are the first steps in creating a protocol for quantifying hydration levels through urine testing in human subjects.
Wearable Devices Using Nanoparticle Chains as Universal Building Blocks with Simple Filtration‐Based Fabrication and Quantum Sensing
Authors: Fan Hua , Maheshwari Vivek
Published: May 2020

Self‐assembled micrometer long gold nanoparticle chains are used as building block to fabricate a range of flexible devices to monitor human physiological signals by an easy filtration method. The chains serve as the base material for all the devices and their interconnects and contact pads as well. The micrometer long chains are an array of nanoparticles with gaps of 1–2 nm between adjacent particles. The gaps serve as quantum tunneling barrier and their modulation is basis of signal sensing in these devices. Deposited on a flexible membrane, the chains monitor temperature, artery pulsation, and electrocardiograms (ECG) signals with ease. This simple method provides an avenue to fabricate low cost integrated wearable devices based on quantum phenomena.
External Stimuli Responsive Bis(anthryl)borylaniline AIEgens for Viscosity and Temperature Sensing: The Game of Molecular Flexibility
Authors: Pandey Umesh Pratap , Thilagar Pakkirisamy
Published: May 2020

External stimuli‐responsive luminogens have attracted a lot of attention in the recent years owing to their potential applications in various fields such as sensing, bio‐probes, and optical devices. In this work, the design and synthesis of a new class of external stimuli‐responsive anthracene based fluorescent bis‐(anthryl)boryl anilines 1 and 2 are disclosed. The electronic and optical properties of these compounds are fine‐tuned by varying the amine donor strength. Using steady‐state and time‐resolved photoluminescnece studies in both solution and condensed state together with computational studies (both ground and excited state), it is established that both 1 and 2 exhibit molecular motion dependent emission characteristics. Owing to their molecular conformational flexibility and inherent charge transfer characteristics, 1 and 2 show intriguing optical features such as aggregation induced emission enhancement, viscochromism, temperature sensing, and mechanoluminescence as compared to structurally rigid tris(9‐anthryl)boron without amine donor moieties. These unique properties of 1 and 2 are utilized for detecting local viscosity and temperature sensing over a wide range from 190–300 K. Compound 2 emits pure white light ((Commission internationale de l'éclairage) CIE 0.33, 0.33) at 250 K.
Compact Optical Polarization‐Insensitive Zoom Metalens Doublet
Authors: Wei Yunxuan , Wang Yuxi , Feng Xing , Xiao Shunyuan , Wang Zhaokun , Hu Tie , Hu Manchen , Song Jinwen , Wegener Martin , Zhao Ming , Xia Jinsong , Yang Zhenyu
Published: May 2020

Metasurface‐based lenses (metalenses) offer specific conceptual advantages compared to ordinary refractive lenses. For example, it is possible to tune the focal length of a metalens doublet by varying the relative angle between the two metalenses while fixing their distance, leading to an extremely compact zoom lens. An improved polarization‐insensitive design based on silicon nanocylinders on silica substrates is presented. This design is realized and characterized experimentally at 1550 nm wavelength. By varying the relative angle between the metalenses in steps of 10°, tuning of the doublet focal length is demonstrated from −54 mm to ±3 mm to +54 mm. This results in a zoom factor of an imaging system varying between 1 and 18. For positive focal lengths, the doublet focusing efficiency has a minimum of 34% and a maximum of 83%. Experiment and theory are in very good agreement.
Versatile Cross‐Polarization Conversion Chiral Metasurface for Linear and Circular Polarizations
Authors: Fei Peng , Vandenbosch Guy A. E. , Guo Weihua , Wen Xin , Xiong Di , Hu Wei , Zheng Qi , Chen Xing
Published: May 2020

In this work, first the necessary conditions for a versatile cross‐polarization conversion meta‐atom that operates both for linear and circular cross polarizations are discussed. Based on these, a versatile chiral metasurface cross‐polarization converter is proposed. The correspondence between its physical geometry and polarization domain characteristics is studied. To verify the design concept, a prototype is fabricated and measured. An effective vertical and horizontal linear cross‐polarization conversion is achieved from 29.3 to 38.8 GHz (27.90%) and from 34.0 to 36.6 GHz (7.36%), respectively. Furthermore, the proposed converter also achieves circular polarization handedness rotation from 34.5 to 36.6 GHz (5.91%).
Enhanced Operational Stability of Perovskite Light‐Emitting Electrochemical Cells Leveraging Ionic Additives
Authors: Mishra Aditya , Alahbakhshi Masoud , Haroldson Ross , Bastatas Lyndon D. , Gu Qing , Zakhidov Anvar A. , Slinker Jason D.
Published: May 2020

Hybrid perovskites are emerging as highly efficient materials for optoelectronic applications, however, their operational lifetime has remained a limiting factor for their continued progress. In this work, perovskite light emitting electrochemical cells utilizing an optimized fraction of lithium hexafluorophosphate (LiPF6) salt additive exhibit enhanced stability. At 0.5 wt% LiPF6, devices exhibit 100 h operation at high brightness in excess of 800 cd m−2 under constant current driving, achieving a maximum luminance of 3260 cd m−2 and power efficiency of 9.1 Lm W−1. This performance extrapolates to a 6700 h luminance half‐life from 100 cd m−2, a 5.6‐fold improvement over devices with no LiPF6. Analysis under constant voltage driving reveals three current regimes, with lithium addition strongly enhancing current in the second and third regimes. The third regime correlates lower rates of luminance with lowered current flow. These losses are mitigated by LiPF6 addition, an effect postulated to arise from preservation of perovskite structure. Electrochemical impedance spectroscopy with equivalent circuit modeling reveals that electrical double layer widths are minimized at 0.5 wt% LiPF6 and inversely correlated with efficient performance. These results demonstrate that an optimal LiPF6 concentration improves stability and efficiency through improved double layer formation and retention of perovskite structure.
Long‐Lived Efficient Inverted Organic Light‐Emitting Diodes Developed by Controlling Carrier Injection Barrier into Emitting Layer
Authors: Fukagawa Hirohiko , Ito Hirokazu , Kawamura Shizuka , Iwasaki Yukiko , Inagaki Kaito , Oono Taku , Sasaki Tsubasa , Shimizu Takahisa
Published: May 2020

Inverted organic light‐emitting diodes (iOLEDs), where electrons are injected without the use of reactive metals such as alkali metals, have attracted extensive attention owing to their higher air stability than conventional OLEDs (cOLEDs). Although iOLEDs are promising for use in applications such as flexible displays, little is known about the emitting layer most suitable for improving their operational lifetime, which is one of the most important parameters for practical applications. Here, it is shown that the operational lifetimes of both iOLEDs and cOLEDs strongly depend on the hole and electron injection barriers of the emitting layer, which is clarified by synthesizing novel emitting hosts having similar molecular structures but different energy levels. The cOLED employing the novel emitting host with the largest hole injection barrier exhibits the shortest operational lifetime, whereas the iOLED employing the same emitting host exhibits the longest operational lifetime owing to the smallest electron injection barrier. The appropriate energy levels of the emitting layer can differ between iOLEDs and cOLEDs since the management conditions of the carriers, excitons, and polarons in iOLEDs are different from those in cOLEDs. A green iOLED with performance equivalent to that of state‐of‐the‐art green cOLEDs reported in the literature is first realized.
Distribution of Market Facilitation Program Payments and their Financial Impact for Illinois, Kansas, and Minnesota Farms
Authors: Paulson Nicholas D. , Featherstone Allen M. , Hadrich Joleen C.
Published: May 2020

The recent infusion of cash into production agriculture due to damages from retaliatory trade actions has been large. Up to $28 billion has been authorized through the Trade Mitigation Program in 2018 and 2019, accounting for a significant share of farm income and providing liquidity in an extended period of low prices. Using farm‐level data from Illinois, Kansas, and Minnesota, this research examines the importance of market facilitation program payments in supporting incomes and reducing credit default risk. Results illustrate the additional liquidity provided for farms, and the distributional effects across states and among farms within each state.
Comparison of Active Learning Techniques: Audience Response Questions Versus Small Group Discussion on Immediate‐ and Long‐term Knowledge Gain
Authors: Jordan Jaime , Missaghi Babak , Douglass Amy , Tolles Juliana
Published: May 2020

Objectives

Active learning techniques help with motivation, involvement, and retention during didactics. There are few studies comparing different active learning methods, and these have yielded mixed results. The objective of this study was to compare the effect of two active learning methods—small‐group discussion and audience response system (ARS)—on immediate‐ and long‐term knowledge gain.

Methods

This was a prospective experimental study of emergency medicine (EM) subinterns and residents. Participants were randomized into two groups, and baseline knowledge was assessed with a multiple‐choice pretest. Didactic sessions on salicylate toxicity and ocular trauma were given to both groups utilizing either small‐group discussion or ARS. A crossover design was utilized to ensure that both groups received instruction by each method. A multiple‐choice posttest was administered following the didactics and again 2 months later. Pre‐ and posttests were identical. All test items were written by an academic faculty member with advanced training in medical education and item writing and were based on the goals and objectives of the session. Test items were piloted with a reference group of learners. Didactic instructors were blinded to test items. Data were analyzed using a linear mixed‐effects model.

Results

Thirty‐eight subinterns and residents participated in the study. Both instructional methods showed immediate‐ and long‐term knowledge gain. The linear mixed‐effects model did not demonstrate any significant difference between instructional methods on immediate knowledge gain (mean difference = 0.18, p = 0.62, 95% confidence interval [CI] = −0.52 to 0.88) or long‐term knowledge gain (mean difference = −0.42, p = 0.36, 95% CI = −1.32 to 0.47).

Conclusion

In this small study, there was no significant difference between instructional methods on immediate‐ and long‐term knowledge gain in EM subinterns and residents.
Discrete element method study on hopper discharge behaviors of binary mixtures of nonspherical particles
Authors: Zhao Ya , Chew Jia Wei
Published: May 2020

This study is aimed at unveiling the influence of binary mixtures of nonspherical particles on hopper discharge behavior, which remains poorly understood. The discrete element method (DEM) is employed to simulate seven particle types with aspect ratios between 0 and 2 (namely, a sphere, two ellipsoids, two cylinders, and two cuboids) with the same volume. Seven monodisperse systems and twelve binary‐shape mixtures are assessed. For the monodisperse systems, particle shape is the dominant factor dictating discharge rate, compared to other factors like aspect ratio, preferential orientation, and packing. Regarding the binary‐shape mixtures, the discharge rates are similar for all twelve mixtures, reflecting a surprising lack of shape effects, which in turn means the negligible impact of solid volume fraction, aspect ratio, and segregation extent. Moreover, collision force is generally negatively correlated with discharge rate.
Kβ X‐Ray Emission Spectroscopic Study of a Second‐Row Transition Metal (Mo) and Its Application to Nitrogenase‐Related Model Complexes
Authors: Castillo Rebeca G. , Henthorn Justin T. , McGale Jeremy , Maganas Dimitrios , DeBeer Serena
Published: May 2020

In recent years, X‐ray emission spectroscopy (XES) in the Kβ (3p‐1s) and valence‐to‐core (valence‐1s) regions has been increasingly used to study metal active sites in (bio)inorganic chemistry and catalysis, providing information about the metal spin state, oxidation state and the identity of coordinated ligands. However, to date this technique has been limited almost exclusively to first‐row transition metals. In this work, we present an extension of Kβ XES (in both the 4p‐1s and valence‐to‐1s [or VtC] regions) to the second transition row by performing a detailed experimental and theoretical analysis of the molybdenum emission lines. It is demonstrated in this work that Kβ2 lines are dominated by spin state effects, while VtC XES of a 4d transition metal provides access to metal oxidation state and ligand identity. An extension of Mo Kβ XES to nitrogenase‐relevant model complexes shows that the method is sufficiently sensitive to act as a spectator probe for redox events that are localized at the Fe atoms. Mo VtC XES thus has promise for future applications to nitrogenase, as well as a range of other Mo‐containing biological cofactors. Further, the clear assignment of the origins of Mo VtC XES features opens up the possibility of applying this method to a wide range of second‐row transition metals, thus providing chemists with a site‐specific tool for the elucidation of 4d transition metal electronic structure.
Independent Generation and Time‐Resolved Detection of 2′‐Deoxyguanosin‐N2‐yl Radicals
Authors: Zheng Liwei , Dai Xiaojuan , Su Hongmei , Greenberg Marc M.
Published: May 2020

Guanine radicals are important reactive intermediates in DNA damage. Hydroxyl radical (HO.) has long been believed to react with 2′‐deoxyguanosine (dG) generating 2′‐deoxyguanosin‐N1‐yl radical (dG(N1‐H).) via addition to the nucleobase π‐system and subsequent dehydration. This basic tenet was challenged by an alternative mechanism, in which the major reaction of HO. with dG was proposed to involve hydrogen atom abstraction from the N2‐amine. The 2′‐deoxyguanosin‐N2‐yl radical (dG(N2‐H).) formed was proposed to rapidly tautomerize to dG(N1‐H).. We report the first independent generation of dG(N2‐H). in high yield via photolysis of 1. dG(N2‐H). is directly observed upon nanosecond laser flash photolysis (LFP) of 1. The absorption spectrum of dG(N2‐H). is corroborated by DFT studies, and anti‐ and syn‐dG(N2‐H). are resolved for the first time. The LFP experiments showed no evidence for tautomerization of dG(N2‐H). to dG(N1‐H). within hundreds of microseconds. This observation suggests that the generation of dG(N1‐H). via dG(N2‐H). following hydrogen atom abstraction from dG is unlikely to be a major pathway when HO. reacts with dG.
Highly Selective Removal of Perfluorinated Contaminants by Adsorption on All‐Silica Zeolite Beta
Authors: Van den Bergh Matthias , Krajnc Andraž , Voorspoels Stefan , Tavares Sergio Rodrigues , Mullens Steven , Beurroies Isabelle , Maurin Guillaume , Mali Gregor , De Vos Dirk E.
Published: May 2020

Perfluorinated alkylated substances (PFASs) are widely used in industrial and commercial applications, leading to a widespread occurrence of these persistent and harmful contaminants in our environment. Removal of these compounds from surface and waste waters is being mandated by European and U.S. governments. Currently, there are no treatment techniques available that lower the concentrations of these compounds for large water bodies in a cost‐ and energy‐efficient way. We hereby propose a hydrophobic, all‐silica zeolite Beta material that is a highly selective and high‐capacity adsorbent for PFASs, even in the presence of organic competitors. Advanced characterization data demonstrate that the adsorption process is driven by a very negative adsorption enthalpy and favorable steric factors.
Biosynthesis of Biscognienyne B Involving a Cytochrome P450‐Dependent Alkynylation
Authors: Lv Jian‐Ming , Gao Yao‐Hui , Zhao Huan , Awakawa Takayoshi , Liu Ling , Chen Guo‐Dong , Yao Xin‐Sheng , Hu Dan , Abe Ikuro , Gao Hao
Published: May 2020

The alkyne is a biologically significant moiety found in many natural products and a versatile functional group widely used in modern chemistry. Recent studies have revealed the biosynthesis of acetylenic bonds in fatty acids and amino acids. However, the molecular basis for the alkynyl moiety in acetylenic prenyl chains occurring in a number of meroterpenoids remains obscure. Here, we identify the biosynthetic gene cluster and characterize the biosynthetic pathway of an acetylenic meroterpenoid biscognienyne B based on heterologous expression, feeding experiments, and in vitro assay. This work shows that the alkyne moiety is constructed by an unprecedented cytochrome P450 enzyme BisI, which shows promiscuous activity towards C5 and C15 prenyl chains. This finding provides an opportunity for discovery of new compounds, featuring acetylenic prenyl chains, through genome mining, and it also expands the enzyme inventory for de novo biosynthesis of alkynes.
Long‐term seagrass degradation: Integrating landscape, demographic, and genetic responses
Authors: Manent Pablo , Bañolas Gonzalo , Alberto Filipe , Curbelo Leticia , Espino Fernando , Tuya Fernando
Published: May 2020

Seagrass meadows are crucial habitats on nearshore areas, which are exposed to human disturbances that frequently cause seagrass loss. Although demographic and mapping data have been widely used in long‐term monitoring programmes, the integration of multi‐locus genotype data through time remains rare.

The present work links, for the first time, landscape, demographic, and genetic data for a seagrass, so as to explore long‐term responses to persistent human impacts. The temporal patterns in meadow area, shoot density, and clonal and genetic diversity of three Cymodocea nodosa meadows were compared: in one meadow directly affected by the construction of an industrial port and in two control areas. The hypothesis tested was that seagrass deterioration and subsequent habitat loss at the affected meadow would be associated with a reduction of seagrass clonal and genetic diversity.

The results show significant reductions in both meadow area (from approx. 21 to 1.5 ha) and shoot density (from approx. 1,800 to 400 shoots per m2) at the impacted meadow, with concurrently reduced clonal and allelic richness (by approx. 22%), as well as heterozygosity (HLmean, approx. 21%; Hobs, approx. 12%). These descriptors, however, remained stable, or even increased, in the controls.

Importantly for seagrass management, multi‐disciplinary analysis made it possible to link slower, large‐scale, landscape and genetic degradation processes with faster demographic deterioration on an intermediate meadow scale. Multi‐locus genotype data were also crucial for revealing long‐term degradation processes at the genetic level, which is undetectable by traditional monitoring techniques.

In summary, this holistic approach provides a valuable framework for long‐term seagrass monitoring programmes to detect cumulative signals of seagrass meadow degradation across a range of scales.
Costly teeth? Gestation length in primates suggests that neonate dentition is not expensive to produce
Authors: Mongle Carrie S. , Koenig Andreas , Samonds Karen E. , Smaers Jeroen B. , Borries Carola
Published: May 2020

Variation in the relationship between gestation length and body mass can arise because different types of tissue require varying amounts of energy to build, and not all species build such tissues in the same proportions. Given that a pregnant female has a finite amount of energy, trade‐offs between investment in different tissues may occur. Here we examine if dental precocity accounts for variation in primate gestation length. If true, this could explain why folivorous species with precocial dentition have longer gestation lengths than predicted by neonatal brain and body mass. We compiled data on gestation length, neonate and adult female body and brain mass from the literature. We used published postcanine eruption schedules at 4 months of age and measured the total occlusal area as dental endowment to approximate dental precocity at birth. Species with embryonic delay in growth or altricial neonates were not considered because they represent grade shifts regarding gestation length. Consequently, our data were biased toward Simiiformes and Old World monkeys, specifically. We performed a phylogenetic generalized least squares regression (pGLS) of neonate brain mass in relation to neonate body mass, and a second pGLS with dental endowment as an additional predictor variable. Including dental endowment in the pGLS did not improve the model. Dental endowment did not systematically impact primate gestation length. Concordant with results from previous studies, this indicates that the energetically expensive period of tooth mineralization may occur postnatally. More data are required to examine if the results are typical across primates.
Einsatz von Fertigteilen im massiven Verkehrswasserbau
Authors: Lühr Stefan , Stephan Christoph , Westendarp Andreas , Kunz Claus
Published: May 2020

In den kommenden Jahren steht im Bereich der Wasserstraßen‐ und Schifffahrtsverwaltung des Bundes (WSV) eine Vielzahl an großen Baumaßnahmen in den Bereichen Ersatzneubau und Grundinstandsetzung von massiven Wasserbauwerken an. Diese Maßnahmen müssen trotz hoher Anforderungen an die Dauerhaftigkeit und Verfügbarkeit massiver Wasserbauwerke zuverlässig, effizient und kostengünstig abgewickelt werden. Der Einsatz von Fertigteilen und Teilfertigteilen aus Stahlbeton bietet in diesem Zusammenhang interessante technische und wirtschaftliche Möglichkeiten. Das diesbezügliche Anwendungspotenzial soll gezielt analysiert, bewertet und genutzt werden. Die notwendigen Voraussetzungen für eine systematische Verwendung von Fertigteilen im Wasserbau bis hin zu Regelungen für Bemessung, Baustoffe und Bauausführung werden im Rahmen eines FuE‐Vorhabens der Bundesanstalt für Wasserbau (BAW) erarbeitet.