bluuebunny/crossref_metadata_2025 huggingface dataset:
Device‐Level Photonic Memories and Logic Applications Using Phase‐Change Materials
Authors: Cheng Zengguang , Ríos Carlos , Youngblood Nathan , Wright C. David , Pernice Wolfram H. P. , Bhaskaran Harish
Published: June 2018

Inspired by the great success of fiber optics in ultrafast data transmission, photonic computing is being extensively studied as an alternative to replace or hybridize electronic computers, which are reaching speed and bandwidth limitations. Mimicking and implementing basic computing elements on photonic devices is a first and essential step toward all‐optical computers. Here, an optical pulse‐width modulation (PWM) switching of phase‐change materials on an integrated waveguide is developed, which allows practical implementation of photonic memories and logic devices. It is established that PWM with low peak power is very effective for recrystallization of phase‐change materials, in terms of both energy efficiency and process control. Using this understanding, multilevel photonic memories with complete random accessibility are then implemented. Finally, programmable optical logic devices are demonstrated conceptually and experimentally, with logic “OR” and “NAND” achieved on just a single integrated photonic phase‐change cell. This study provides a practical and elegant technique to optically program photonic phase‐change devices for computing applications.
A Silica‐Aerogel‐Reinforced Composite Polymer Electrolyte with High Ionic Conductivity and High Modulus
Authors: Lin Dingchang , Yuen Pak Yan , Liu Yayuan , Liu Wei , Liu Nian , Dauskardt Reinhold H. , Cui Yi
Published: June 2018

High‐energy all‐solid‐state lithium (Li) batteries have great potential as next‐generation energy‐storage devices. Among all choices of electrolytes, polymer‐based systems have attracted widespread attention due to their low density, low cost, and excellent processability. However, they are generally mechanically too weak to effectively suppress Li dendrites and have lower ionic conductivity for reasonable kinetics at ambient temperature. Herein, an ultrastrong reinforced composite polymer electrolyte (CPE) is successfully designed and fabricated by introducing a stiff mesoporous SiO2 aerogel as the backbone for a polymer‐based electrolyte. The interconnected SiO2 aerogel not only performs as a strong backbone strengthening the whole composite, but also offers large and continuous surfaces for strong anion adsorption, which produces a highly conductive pathway across the composite. As a consequence, a high modulus of ≈0.43 GPa and high ionic conductivity of ≈0.6 mS cm−1 at 30 °C are simultaneously achieved. Furthermore, LiFePO4–Li full cells with good cyclability and rate capability at ambient temperature are obtained. Full cells with cathode capacity up to 2.1 mAh cm−2 are also demonstrated. The aerogel‐reinforced CPE represents a new design principle for solid‐state electrolytes and offers opportunities for future all‐solid‐state Li batteries.
Enlarged CoO Covalency in Octahedral Sites Leading to Highly Efficient Spinel Oxides for Oxygen Evolution Reaction
Authors: Zhou Ye , Sun Shengnan , Song Jiajia , Xi Shibo , Chen Bo , Du Yonghua , Fisher Adrian C. , Cheng Fangyi , Wang Xin , Zhang Hua , Xu Zhichuan J.
Published: June 2018

Cobalt‐containing spinel oxides are promising electrocatalysts for the oxygen evolution reaction (OER) owing to their remarkable activity and durability. However, the activity still needs further improvement and related fundamentals remain untouched. The fact that spinel oxides tend to form cation deficiencies can differentiate their electrocatalysis from other oxide materials, for example, the most studied oxygen‐deficient perovskites. Here, a systematic study of spinel ZnFexCo2−xO4 oxides (x = 0–2.0) toward the OER is presented and a highly active catalyst superior to benchmark IrO2 is developed. The distinctive OER activity is found to be dominated by the metal–oxygen covalency and an enlarged CoO covalency by 10–30 at% Fe substitution is responsible for the activity enhancement. While the pH‐dependent OER activity of ZnFe0.4Co1.6O4 (the optimal one) indicates decoupled proton–electron transfers during the OER, the involvement of lattice oxygen is not considered as a favorable route because of the downshifted O p‐band center relative to Fermi level governed by the spinel's cation deficient nature.
On‐Chip Dual Electro‐Optic and Optoelectric Modulation Based on ZnO Nanowire‐Coated Photonic Crystal Nanocavity
Authors: Xie Jingya , Hu Xiaoyong , Li Chong , Wang Feifan , Xu Peizhen , Tong Limin , Yang Hong , Gong Qihuang
Published: June 2018

Electronic–photonic hybrid integrated circuits represent the essential basis of next‐generation ultrahigh‐speed information processing chips, which will require ultrafast and ultralow‐energy‐consumption electronic and photonic information interconversion and modulation, i.e., on‐chip dual electro‐optic and optoelectric modulation. However, this type of modulation has not been realized to date because of an absence of materials that demonstrate sufficient intrinsic electro‐optic and optoelectric responses simultaneously. On‐chip dual electro‐optic and optoelectric modulation is experimentally realized here based on refractive index variation of a ZnO nanowire driven by the gate voltage and electrical conductivity changes in this nanowire caused by the strong localized light field of a silicon nitride photonic crystal nanocavity mode. A low gate voltage of 1.5 V induces a large shift of 7 nm in the Fano‐like resonance wavelength and modulates the propagation state of an 800 nm light signal with a large modulation depth of 75%. Additionally, weak signal light with power as low as 0.4 µW induces a modulation depth of 60% in the electric signal. On‐chip conversion between electronic and photonic signals thus is achieved. This work paves the way toward realization of novel nanoscale multifunctional optoelectronic integrated devices and provides an on‐chip platform for the study of new optoelectronic functional materials.
Cross‐linked poly(methyl methacrylate)/multiwall carbon nanotube nanocomposites for environmental treatment
Authors: Hussein Mahmoud A. , Albeladi Hasinah K. , Elsherbiny Abeer S. , El‐Shishtawy Reda M. , Al‐romaizan Abeer N.
Published: June 2018

Eco‐friendly cross‐linked poly(methyl methacrylate)/multiwall carbon nanotube nanocomposites with general abbreviation (C‐PMMA/CNTs1‐5) have been synthesized and applied efficiently for environmental treatment from methyl green (MG) dye. C‐PMMA/CNTs1‐5 were prepared via in situ cross‐linked polymerization method using 1,12‐diaminododecane as the cross‐linker. CNTs were enforced with variable loading (2, 5, 10, 20 and 40) wt% in situ while the cross‐linking polymerization occurred. The fabricated nanocomposites were spectroscopically regarded by common characterization methods. These include FTIR spectra, XRD diffractograms, SEM & TEM micrographs, and TGA & DTA thermograms. FTIR and XRD showed obvious evidence for the composite formation. A good spreading of CNTs inside C‐PMMA matrix has been investigated by SEM and TEM micrographs. TGA showed enhanced thermal stability behavior in all formulations. Our main target in this study is to test the viability of eliminating MG dye from aqueous solutions by C‐PMMA/CNT nanocomposites. The C‐PMMA/CNT3 nanocomposite showed Langmuir adsorption capacity of 6.85 mmol/g for MG dye at 25°C. The adsorption equilibrium could be reached within 120 min. The adsorption kinetics of MG onto C‐PMMA/CNTs3 was obeyed very well pseudo‐second‐order model. Enthalpy (∆H°) and entropy (∆S°) of adsorption were 23.15 kJ/mol and 134.1 J mol−1 K−1, respectively. The values of ∆H° and ∆G° all designated that the adsorption of MG onto C‐PMMA/CNT3 nanocomposites was a physisorption in nature.
Histone Deacetylase 7‐Derived Peptides Play a Vital Role in Vascular Repair and Regeneration
Authors: Pan Yiwa , Yang Junyao , Wei Yongzhen , Wang He , Jiao Rongkuan , Moraga Ana , Zhang Zhongyi , Hu Yanhua , Kong Deling , Xu Qingbo , Zeng Lingfang , Zhao Qiang
Published: June 2018

Cardiovascular disease is a leading cause of morbidity and mortality globally. Accumulating evidence indicates that local resident stem/progenitor cells play an important role in vascular regeneration. Recently, it is demonstrated that a histone deacetylase 7‐derived 7‐amino acid peptide (7A, MHSPGAD) is critical in modulating the mobilization and orientated differentiation of these stem/progenitor cells. Here, its therapeutic efficacy in vascular repair and regeneration is evaluated. In vitro functional analyses reveal that the 7A peptide, in particular phosphorylated 7A (7Ap, MH[pSer]PGAD), could increase stem cell antigen‐1 positive (Sca1+) vascular progenitor cell (VPC) migration and differentiation toward an endothelial cell lineage. Furthermore, local delivery of 7A as well as 7Ap could enhance angiogenesis and ameliorate vascular injury in ischaemic tissues; these findings are confirmed in a femoral artery injury model and a hindlimb ischaemia model, respectively. Importantly, sustained delivery of 7A, especially 7Ap, from tissue‐engineered vascular grafts could attract Sca1+‐VPC cells into the grafts, contributing to endothelialization and intima/media formation in the vascular graft. These results suggest that this novel type of peptides has great translational potential in vascular regenerative medicine.
High‐Energy Aqueous Lithium Batteries
Authors: Eftekhari Ali
Published: June 2018

Owing to the high voltage of lithium‐ion batteries (LIBs), the dominating electrolyte is non‐aqueous. The idea of an aqueous rechargeable lithium battery (ARLB) dates back to 1994, but it had attracted little attention due to the narrow stable potential window of aqueous electrolytes, which results in low energy density. However, aqueous electrolytes were employed during the 2000s for the fundamental studies of electrode materials in the absence of side reactions such as the decomposition of organic species. The high solubility of lithium bis(trifluoromethane sulfonyl)imide (LiTFSI) in water has introduced new opportunities for high‐voltage ARLBs. Nonetheless, these ideas are somehow overshadowed by the common perception about the essential limitation of the aqueous electrolyte. The electrochemical behaviour of conventional electrode materials can be substantially tuned in the water‐in‐salt electrolytes. The latest idea of utilising a graphite anode in the aqueous water‐in‐salt electrolytes has paved the way towards not only 4‐V ARLB but also a new generation of Li−S batteries with a higher operating voltage and energy efficiency. Furthermore, aqueous electrolytes can provide a cathodically stable environment for Li−O2 batteries. The present paper aims to highlight these emerging opportunities possibly leading to a new generation of LIBs, which can be substantially cheaper and safer.
Out‐of‐hospital cardiac arrests in the toilet in Japan: a population‐based descriptive study
Authors: Kiyohara Kosuke , Nishiyama Chika , Kiguchi Takeyuki , Kobayashi Daisuke , Iwami Taku , Kitamura Tetsuhisa
Published: June 2018

Aim

This study aimed to reveal the characteristics and outcomes of patients with out‐of‐hospital cardiac arrests (OHCAs) occurring in the toilet. These traits provide useful clues for the prevention of OHCAs and the improvement of prehospital care for these patients.

Methods

Out‐of‐hospital cardiac arrest data were obtained from the population‐based, Utstein‐style registry in Osaka City, Japan, between 2009 and 2015. This study identified patients with OHCAs that occurred inside the toilet. The primary end‐point was 1‐month survival with favorable neurological outcome after OHCA.

Results

During the 7‐year study period, a total of 18,458 OHCAs were identified. Of these cases, 849 (4.6%) occurred inside the toilet. Among them, the analysis included 733 patients. The distribution depicting monthly OHCA occurrences showed that OHCAs tended to occur in cold months (28.1% [206/733] from October to December and 30.0% [220/733] from January to March). Most OHCAs occurring inside the toilet were of cardiac origin (91.5% [671/733]), and 36.2% (265/733) were witnessed by bystanders. The proportion of patients with ventricular fibrillation was 5.2% (38/733) and those receiving shocks by public‐access automated external defibrillators was 0.4% (3/733). The proportion of patients with 1‐month survival with favorable neurological outcome was 1.9% (14/733).

Conclusions

Out‐of‐hospital cardiac arrests occurring inside the toilet accounted for 4.6% of all OHCAs and were frequently observed during cold months, and their outcome was poor. Establishment of preventive measures against OHCAs occurring in the toilet as well as earlier recognition of OHCAs are needed.
Cobalt‐katalysierte Kreuzkupplung zwischen Alkenylacetaten und Aryl‐ oder Alkenylzinkpivalaten
Authors: Li Jie , Knochel Paul
Published: June 2018

CoBr2 (5 mol %), in Gegenwart von 2,2′‐Bipyridin (5 mol %), ermöglicht Alkenylierungen zwischen leicht zugänglichen Alkenylacetaten, ‐tosylaten und verschiedenen funktionalisierten Arylzinkpivalaten bei Raumtemperatur. Zusätzlich wurde die Cobaltkatalyse auf Alkenylzinkpivalate angewendet, um substituierte 1,3‐Diene zu erhalten.
Selbstorganisation von funktionellen diskreten dreidimensionalen Architekturen in Wasser
Authors: Taylor Lauren L. K. , Riddell Imogen A. , Smulders Maarten M. J.
Published: June 2018

Der Aufbau von diskreten, selbstorganisierten Architekturen in Wasser fand in den vergangenen Jahren erhebliches Interesse, da sich eine große Anzahl von Anwendungen aus ihrer definierten 3D‐Struktur ergibt. Dieser Aufsatz diskutiert die gemeinsamen Bemühungen von Chemikern aus der supramolekularen Chemie und von Biotechnologen zur Lösung fachspezifischer Aufgaben, die mit dem Aufbau von Anordnungen aus synthetischen bzw. biologisch abgeleiteten Komponenten verbunden sind. In Zukunft wird ein stärker interdisziplinärer Forschungsansatz die Entwicklung von Komplexen mit realen Anwendungen beschleunigen, welche die Vorteile der Kompartimentierung nutzen. Um dies zu unterstützen, sollen hier die Fortschritte zusammengefasst werden, die bei der Entwicklung diskreter, wasserlöslicher Anordnungen erzielt wurden, unter besonderer Berücksichtigung ihrer aktuellen und zukünftigen Anwendungen. Bereiche, in denen das Verständnis und die Methodik von einem auf das andere Gebiet übertragbar sind, werden hervorgehoben, mit der Hoffnung, dass dies zu Fortschritten führt, die auf beiden Gebieten allein nicht möglich wären.
Cobalt‐Catalyzed Cross‐Couplings between Alkenyl Acetates and Aryl or Alkenyl Zinc Pivalates
Authors: Li Jie , Knochel Paul
Published: June 2018

CoBr2 (5 mol %) in the presence of 2,2′‐bipyridyl (5 mol %) enables electrophilic alkenylations between easily accessible alkenyl acetates or tosylates and various functionalized aryl zinc pivalates at ambient temperature. This cobalt‐catalyzed process was further applicable to alkenyl zinc pivalates to provide substituted 1,3‐dienes.
Stratification of Systemic Lupus Erythematosus Patients Into Three Groups of Disease Activity Progression According to Longitudinal Gene Expression
Authors: Toro‐Domínguez Daniel , Martorell‐Marugán Jordi , Goldman Daniel , Petri Michelle , Carmona‐Sáez Pedro , Alarcón‐Riquelme Marta E.
Published: June 2018

Objective

The highly heterogeneous clinical presentation of systemic lupus erythematosus (SLE) is characterized by the unpredictable occurrence of disease flares and organ damage. Attempts to stratify lupus patients have been limited to classification based on clinical information, leading to unsuccessful clinical trials and controversial research results. This study was undertaken to develop and validate a robust method to stratify patients with lupus according to longitudinal disease activity and whole‐genome gene expression data in order to establish subgroups of patients who share disease progression mechanisms.

Methods

We used a cluster‐based approach to stratify SLE patients based on the correlation between disease activity scores and longitudinal gene expression information. Clustering robustness was evaluated by the bootstrap method, and the clusters were characterized in terms of clinical and functional features.

Results

We observed a clear partition into 3 different disease clusters in 2 independent sets of patients, one pediatric and one adult, which was not influenced by treatment, race, or other source of bias. Two of the clusters differentiated into a group showing a correlation between the percentage of neutrophils and disease activity progression and a group showing a correlation between the percentage of lymphocytes and disease activity progression. The third cluster, in which the percentage of neutrophils correlated to a lesser degree with disease activity, was functionally more heterogeneous. Patients in the neutrophil‐driven clusters had an increased risk of developing proliferative nephritis.

Conclusion

Our findings indicate that SLE patients can be stratified into 3 subgroups of patients who show different mechanisms of disease progression and are clinically differentiated. Our results have important implications for treatment options, the design of clinical trials, our understanding of the etiology of the disease, and the prediction of severe glomerulonephritis.
Improving the Performance of Batteries by Using Multi‐Pyrene PTMA Structures
Authors: Hergué Noémie , Ernould Bruno , Minoia Andrea , Lazzaroni Roberto , Gohy Jean‐François , Dubois Philippe , Coulembier Olivier
Published: June 2018

Well‐defined pyrene‐based poly(2,2,6,6‐tetramethylpiperidinyloxy‐4‐yl methacrylate) (PTMA) (co)polymers have been synthesized and combined with multi‐wall carbon nanotubes (CNTs) as electrode material for organic radical batteries. The influence of the number of pyrene pendent groups on the electrochemical response of the nanocomposite materials has been assessed, focusing on the capacity retention upon charge/discharge cycling and on the cycling rate. In parallel, the interactions between the polymethacrylate chains and the CNT surface have been investigated with molecular modeling techniques, to shed light on the nature and stability of the functionalized PTMA/CNT interface.
Multispecies activity screening of microcin J25 mutants yields antimicrobials with increased specificity toward pathogenic Salmonella species relative to human commensal Escherichia coli
Authors: Ritter Seth C. , Yang Mike L. , Kaznessis Yiannis N. , Hackel Benjamin J.
Published: June 2018

Modern large‐scale agricultural practices that incorporate high density farming with subtherapeutic antibiotic dosing are considered a major contributor to the rise of antibiotic‐resistant bacterial infections of humans with species of Salmonella being a leading agriculture‐based bacterial infection. Microcin J25, a potent and highly stable antimicrobial peptide active against Enterobacteriaceae, is a candidate antimicrobial against multiple Salmonella species. Emerging evidence supports the hypothesis that the composition of the microbiota of the gastrointestinal tract prevents a variety of diseases by preventing infectious agents from proliferating. Reducing clearance of off‐target bacteria may decrease susceptibility to secondary infection. Of the Enterobacteriaceae susceptible to microcin J25, Escherichia coli are the most abundant within the human gut. To explore the modulation of specificity, a collection of 207 mutants encompassing 12 positions in both the ring and loop of microcin J25 was built and tested for activity against Salmonella and E. coli strains. As has been found previously, mutational tolerance of ring residues was lower than loop residues, with 22% and 51% of mutations, respectively, retaining activity toward at least one target within the target organism test panel. The multitarget screening elucidated increased mutational tolerance at position G2, G3, and G14 than previously identified in panels composed of single targets. Multiple mutations conferred differential response between the different targets. Examination of specificity differences between mutants found that 30% showed significant improvements to specificity toward any of the targets. Generation and testing of a combinatorial library designed from the point‐mutant study revealed that microcin J25I13T reduces off‐target activity toward commensal human‐derived E. coli isolates by 81% relative to Salmonella enterica serovar Enteritidis. These in vitro specificity improvements are likely to improve in vivo treatment efficacy by reducing clearance of commensal bacteria in the gastrointestinal tract of hosts.
Rational approach to improve ansamitocin P‐3 production by integrating pathway engineering and substrate feeding in Actinosynnema pretiosum
Authors: Du Zhi‐Qiang , Zhong Jian‐Jiang
Published: June 2018

Ansamitocin P‐3 (AP‐3) produced by Actinosynnema pretiosum is an important antitumor agent for cancer treatment, but its market supply suffers from a low production titer. The role of AP‐3 unusual glycolate unit supply on its biosynthesis was investigated in this work by overexpressing the responsible gene cluster asm13‐17 in A. pretiosum (WT). As a result, the accumulation of AP‐3 and its intermediate glyceryl‐S‐ACP in the asm13‐17‐overexpressed strain (Oasm13‐17) versus WT was enhanced by 1.94 and 1.49‐fold, respectively. To provide a higher supply of another precursor 3‐amino‐5‐hydroxybenzoic acid, asmUdpg was also overexpressed in Oasm13‐17 (Oasm13‐17:asmUdpg), and an improved AP‐3 titer of 680.5 mg/L was achieved in shake flasks. To further enhance the AP‐3 titer, a rational fed‐batch strategy was developed in bioreactor fermentation of Oasm13‐17:asmUdpg; and by pulse feeding 15 g/L fructose and 1.64 g/L isobutanol at 60, 96, and 120 hr, the AP‐3 production level reached 757.7 mg/L, which is much higher than ever reported in bioreactors. This work demonstrated that a rational approach combining precursor pathway engineering with substrate feeding was very effective in enhancing the AP‐3 titer, and this enabling methodology would be helpful to industrial production of this eye‐catching drug.
Resemblance of the human liver sinusoid in a fluidic device with biomedical and pharmaceutical applications
Authors: Ortega‐Ribera Martí , Fernández‐Iglesias Anabel , Illa Xavi , Moya Ana , Molina Víctor , Maeso‐Díaz Raquel , Fondevila Constantino , Peralta Carmen , Bosch Jaume , Villa Rosa , Gracia‐Sancho Jordi
Published: June 2018

Maintenance of the complex phenotype of primary hepatocytes in vitro represents a limitation for developing liver support systems and reliable tools for biomedical research and drug screening. We herein aimed at developing a biosystem able to preserve human and rodent hepatocytes phenotype in vitro based on the main characteristics of the liver sinusoid: unique cellular architecture, endothelial biodynamic stimulation, and parenchymal zonation. Primary hepatocytes and liver sinusoidal endothelial cells (LSEC) were isolated from control and cirrhotic human or control rat livers and cultured in conventional in vitro platforms or within our liver‐resembling device. Hepatocytes phenotype, function, and response to hepatotoxic drugs were analyzed. Results evidenced that mimicking the in vivo sinusoidal environment within our biosystem, primary human and rat hepatocytes cocultured with functional LSEC maintained morphology and showed high albumin and urea production, enhanced cytochrome P450 family 3 subfamily A member 4 (CYP3A4) activity, and maintained expression of hepatocyte nuclear factor 4 alpha (hnf4α) and transporters, showing delayed hepatocyte dedifferentiation. In addition, differentiated hepatocytes cultured within this liver‐resembling device responded to acute treatment with known hepatotoxic drugs significantly different from those seen in conventional culture platforms. In conclusion, this study describes a new bioengineered device that mimics the human sinusoid in vitro, representing a novel method to study liver diseases and toxicology.
A framework for the identification of promising bio‐based chemicals
Authors: Wu Wenzhao , Long Matthew R. , Zhang Xiaolin , Reed Jennifer L. , Maravelias Christos T.
Published: June 2018

Recent progress in metabolic engineering and synthetic biology enables the use of microorganisms for the production of chemicals—“bio‐based chemicals.” However, it is still unclear which chemicals have the highest economic prospect. To this end, we develop a framework for the identification of such promising ones. Specifically, we first develop a genome‐scale constraint‐based metabolic modeling approach, which is used to identify a candidate pool of 209 chemicals (together with the estimated yield, productivity, and residence time for each) from the intersection of the high‐production‐volume chemicals and the KEGG and MetaCyc databases. Second, we design three screening criteria based on a chemical’s profit margin, market volume, and market size. The total process cost, including the downstream separation cost, is systematically incorporated into the evaluation. Third, given the three aforementioned criteria, we identify 32 products as economically promising if the maximum yields can be achieved, and 22 products if the maximum productivities can be achieved. The breakeven titer that renders zero profit margin for each product is also presented. Comparisons between extracellular and intracellular production, as well as Escherichia coli and Saccharomyces cerevisiae systems are also discussed. The proposed framework provides important guidance for future studies in the production of bio‐based chemicals. It is also flexible in that the databases, yield estimations, and criteria can be modified to customize the screening.
Lamellar Liquid Crystals of In‐Plane Lying Rod‐Like Mesogens with Designer Side‐Chains: The Case of Sliding versus Locked Layers
Authors: Prehm Marko , Enders Claudia , Mang Xiaobin , Zeng Xiangbing , Liu Feng , Ungar Goran , Baumeister Ute , Tschierske Carsten
Published: June 2018

The dimensionality of self‐assembled nanostructures plays an essential role for their properties and applications. Herein, an understanding of the transition from weakly to strongly coupled layers in soft matter systems is provided involving in‐plane organized π‐conjugated rods. For this purpose, bolaamphiphilic triblock molecules consisting of a rigid biphenyl core, polar glycerol groups at the ends, and a branched (swallow‐tail) or linear alkyl or semiperfluoroalkyl chain in lateral position have been synthesized and investigated. Besides weakly coupled lamellar isotropic (LamIso), lamellar nematic (LamN) and sliding lamellar smectic phases (LamSm), a sequence of three distinct types of strongly coupled (correlated) lamellar smectic phases with either centered (c2mm) or non‐centered rectangular (p2mm) lattice and an intermediate oblique lattices (p2) were observed depending on chain length, chain branching and degree of chain fluorination. This new sequence is explained by the strengthening of the layer coupling and the competition between energetic packing constraints and the entropic contribution of either longitudinal or tangential fluctuations. This example of directed side chain engineering of small generic model compounds provides general clues for morphological design of two‐dimensional and three‐dimensionally coupled lamellar systems involving larger π‐conjugated molecular rods and molecular or supramolecular polymers, being of actual interest in organic electronics and nanotechnology.
Strategies for Reversible Guest Uptake and Release from Metallosupramolecular Architectures
Authors: Kim Tae Y. , Vasdev Roan A. S. , Preston Dan , Crowley James D.
Published: June 2018

The cavities of metallosupramolecular cages can be used to mimic the central spaces of naturally occurring proteins and bind a wide variety of molecular guests. A range of potential applications have arisen from this capacity for host–guest chemistry. However, to truly harness the opportunities thus afforded, methodologies to controllably allow the release and reuptake of guests from the cavities of metallosupramolecular cages are required. Methods to accomplish this have centered upon reversibly altering the character of either the guest or host. This minireview outlines the current approaches used to carry out the binding and release of guests from metallosupramolecular hosts using important examples from the field.
KinITC—One Method Supports both Thermodynamic and Kinetic SARs as Exemplified on FimH Antagonists
Authors: Zihlmann Pascal , Silbermann Marleen , Sharpe Timothy , Jiang Xiaohua , Mühlethaler Tobias , Jakob Roman P. , Rabbani Said , Sager Christoph P. , Frei Priska , Pang Lijuan , Maier Timm , Ernst Beat
Published: June 2018

Affinity data, such as dissociation constants (KD) or inhibitory concentrations (IC50), are widely used in drug discovery. However, these parameters describe an equilibrium state, which is often not established in vivo due to pharmacokinetic effects and they are therefore not necessarily sufficient for evaluating drug efficacy. More accurate indicators for pharmacological activity are the kinetics of binding processes, as they shed light on the rate of formation of protein–ligand complexes and their half‐life. Nonetheless, although highly desirable for medicinal chemistry programs, studies on structure–kinetic relationships (SKR) are still rare. With the recently introduced analytical tool kinITC this situation may change, since not only thermodynamic but also kinetic information of the binding process can be deduced from isothermal titration calorimetry (ITC) experiments. Using kinITC, ITC data of 29 mannosides binding to the bacterial adhesin FimH were re‐analyzed to make their binding kinetics accessible. To validate these kinetic data, surface plasmon resonance (SPR) experiments were conducted. The kinetic analysis by kinITC revealed that the nanomolar affinities of the FimH antagonists arise from both (i) an optimized interaction between protein and ligand in the bound state (reduced off‐rate constant koff) and (ii) a stabilization of the transition state or a destabilization of the unbound state (increased on‐rate constant kon). Based on congeneric ligand modifications and structural input from co‐crystal structures, a strong relationship between the formed hydrogen‐bond network and koff could be concluded, whereas electrostatic interactions and conformational restrictions upon binding were found to have mainly an impact on kon.
Excitation‐Wavelength‐Dependent Emission and Delayed Fluorescence in a Proton‐Transfer System
Authors: Berezin Alexey S. , Vinogradova Katerina A. , Krivopalov Viktor P. , Nikolaenkova Elena B. , Plyusnin Victor F. , Kupryakov Arkady S. , Pervukhina Natalia V. , Naumov Dmitrii Y. , Bushuev Mark B.
Published: June 2018

Manipulating the relaxation pathways of excited states and understanding mechanisms of photochemical reactions present important challenges in chemistry. Here we report a unique zinc(II) complex exhibiting unprecedented interplay between the excitation‐wavelength‐dependent emission, thermally activated delayed fluorescence (TADF) and excited state intramolecular proton transfer (ESIPT). The ESIPT process in the complex is favoured by a short intramolecular OH⋅⋅⋅N hydrogen bond. Synergy between the excitation‐wavelength‐dependent emission and ESIPT arises due to heavy zinc atom favouring intersystem crossing (isc). Reverse intersystem crossing (risc) and TADF are favoured by a narrow singlet–triplet gap, ΔEST≈10 kJ mol−1. These results provide the first insight into how a proton‐transfer system can be modified to show a synergy between the excitation‐wavelength‐dependent emission, ESIPT and TADF. This strategy offers new perspectives for designing ESIPT and TADF emitters exhibiting tunable excitation‐wavelength‐dependent luminescence.
Brønsted Base Assisted Photoredox Catalysis: Proton Coupled Electron Transfer for Remote C−C Bond Formation via Amidyl Radicals
Authors: Jia Jiaqi , Ho Yee Ann , Bülow Raoul F. , Rueping Magnus
Published: June 2018

The synthesis of alkyne‐ and alkene‐decorated lactams has been achieved through a photoredox‐initiated radical cascade reaction. The developed Brønsted base assisted, photoredox‐catalyzed, intramolecular 5‐exo‐trig cyclization/intermolecular radical addition/elimination reaction provides facile access to functionalized γ‐lactams, with good functional group tolerance and high yields.
Chemical Modification of Dehydrated Amino Acids in Natural Antimicrobial Peptides by Photoredox Catalysis
Authors: de Bruijn A. Dowine , Roelfes Gerard
Published: June 2018

Dehydroalanine (Dha) and dehydrobutyrine (Dhb) are remarkably versatile non‐canonical amino acids often found in antimicrobial peptides. This work presents the selective modification of Dha and Dhb in antimicrobial peptides through photocatalytic activation of organoborates under the influence of visible light. Ir(dF(CF3)ppy)2(dtbbpy)PF6 was used as a photoredox catalyst in aqueous solutions for the modification of thiostrepton and nisin. The mild conditions and high selectivity for the dehydrated residues show that photoredox catalysis is a promising tool for the modification of peptide‐derived natural products.
Perceptions of future health and cancer risk in adult survivors of childhood cancer: A report from the Childhood Cancer Survivor Study
Authors: Gibson Todd M. , Li Chenghong , Armstrong Gregory T. , Srivastava Deo Kumar , Leisenring Wendy M. , Mertens Ann , Brinkman Tara M. , Diller Lisa , Nathan Paul C. , Hudson Melissa M. , Robison Leslie L.
Published: June 2018

BACKGROUND

Survivors of childhood cancer are at significant risk for serious chronic health conditions and subsequent cancers because of their prior treatment exposures. However, little is known about survivors' perceptions of their future health risks.

METHODS

This study examined self‐reported levels of concern about future health and subsequent cancer in 15,620 adult survivors of childhood cancer (median age, 26 years; median time since diagnosis, 17 years) and 3991 siblings in the Childhood Cancer Survivor Study. The prevalence of concerns was compared between survivors and siblings, and the impact of participant characteristics and treatment exposures on concerns was examined with multivariable modified Poisson regression to estimate relative risks (RRs) and 95% confidence intervals (CIs).

RESULTS

A substantial proportion of survivors were not concerned about their future health (31%) or developing cancer (40%). The prevalence of concern in survivors was modestly higher (RR for future health, 1.12; 95% CI, 1.09‐1.15) or similar (RR for subsequent cancer, 1.02; 95% CI, 0.99‐1.05) in comparison with siblings. Survivors exposed to high doses of radiation (≥20 Gy) were more likely to report concern (RR for future health, 1.13; 95% CI, 1.09‐1.16; RR for subsequent cancer, 1.14; 95% CI, 1.10‐1.18), but 35% of these high‐risk survivors were not concerned about developing cancer, and 24% were not concerned about their future health.

CONCLUSIONS

A substantial subgroup of survivors were unconcerned about their future health and subsequent cancer risks, even after exposure to treatments associated with increased risk. These survivors may be less likely to engage in beneficial screening and risk‐reduction activities. Cancer 2018. © 2018 American Cancer Society.
Peptide‐Based Hydrogels as a Scaffold for In Situ Synthesis of Metal Nanoparticles: Catalytic Activity of the Nanohybrid System
Authors: Paul Subir , Basu Kingshuk , Das Krishna Sundar , Banerjee Arindam
Published: June 2018

A tripeptide containing an oligo‐methylene group was found to form hydrogels at the two pH extremes (in presence of an acid or a base); however, it does not form a hydrogel at neutral pH. We use this property to obtain a hydrogel of the peptide in the presence of an organic acid, citric acid. The redox potential of citric acid is ideal to reduce Ag+ and Au3+ ions to form the corresponding nanoparticles. Keeping this in mind the hydrogel with citric acid was applied to fabricate silver and gold nanoparticles within the gel phase without the aid of external reducing and stabilising agents. The hydrogels and the peptide nanofiber‐metal nanoparticle based hybrid system were thoroughly characterized by UV‐visible spectroscopy, FEG‐TEM microscopy, FT‐IR spectroscopy, and powder X‐ray diffraction studies. From the FEG‐TEM images it is evident that a considerable amount of Au and Ag nanoparticles are found above the gel nanofibers. Interestingly, the hybrid hydrogel containing silver nanoparticles could be successfully employed as a catalyst in the transformation of p‐nitrophenol to p‐aminophenol and p‐nitroaniline to p‐phenylenediamine. It is also interesting to note that the native hydrogel (without Ag nanoparticles) is unable to act as a catalyst. Moreover, this hybrid hydrogel has been recycled a few times without significant loss of activity, showing the potential of this new nanohybrid system for catalysis.
Formation of Nanofibers with High Water Adhesion by Electrodeposition of Films of Poly(3,4‐ethylenedioxypyrrole) and Poly(3,4‐propylenedioxypyrrole) Substituted by Alkyl Chains
Authors: Sane Omar , Diouf Alioune , Dieng Samba Yandé , Guittard Frédéric , Darmanin Thierry
Published: June 2018

With the aim of controlling the surface hydrophobicity and water adhesion, nanofibrous surfaces were prepared by electropolymerization of 3,4‐ethylenedioxypyrrole (EDOP) and 3,4‐propylenedioxypyrrole (ProDOP) derivatives having various alkyl chains (C3 to C17) grafted to a 3,4‐alkylenedioxy bridge. Depending on whether an EDOP or a ProDOP was used, and the length of the alkyl chain, the surface properties of the resulting polymer were very different. The formation of nanofibrous surfaces was much more favored for ProDOP derivatives. The alkyl chain length has also a huge influence on the formation of nanofibers, and alkyl chains of intermediate length (C9 and C11) gave the best results. Apparent contact angles (θw) of up to 150° were obtained, and the water adhesion properties were highly variable. This work is important for many applications in which the control of interaction forces with a medium is required, such as in oil–water separation membranes or water‐harvesting systems.
Catalyst‐Free Synthesis of Alkylpolyglycosides Induced by High‐Frequency Ultrasound
Authors: Amaniampong Prince Nana , Clément Jean‐Louis , Gigmes Didier , Ortiz Mellet Carmen , García Fernández José M. , Blériot Yves , Chatel Gregory , De Oliveira Vigier Karine , Jérôme François
Published: June 2018

The irradiation of concentrated feeds of carbohydrates in alcoholic solution by high‐frequency ultrasound (550 kHz) induces the formation of alkylpolyglycosides (APGs). This work is distinct from previous reports in that it does not involve any (bio)catalyst or activating agent, it takes place at only 40 °C, thus avoiding degradation of carbohydrates, and it selectively yields APGs with a degree of polymerization in a window of 2–7, an important limitation of the popular Fischer glycosylation. This ultrasound‐based technology proved successful with a range of different valuable carbohydrates and alkyl alcohols. The elucidation of the structure of all the produced glycosides strongly suggests that 1,6‐anhydrosugars formed in situ are key intermediate species.
Satellite‐ and field‐based facies mapping of isolated carbonate platforms from the Kepulauan Seribu Complex, Indonesia
Authors: Utami Dwi Amanda , Reuning Lars , Cahyarini Sri Yudawati
Published: June 2018

Quantitative facies models from modern carbonate are essential for the interpretation of their fossil counterparts. The isolated carbonate platforms of the Kepulauan Seribu archipelago has many atoll‐like islands with reef belts exposed to bidirectional monsoon winds. Statistical analysis based on texture and composition reveal that there are four sedimentary facies; coral grainstone, coral packstone/grainstone, coral‐mollusc packstone and mollusc wackestone. The occurrence of mollusc wackestone in the lagoon is controlled by water depth, while the sand apron and reef front do not show significant facies separation with water depth. The co‐occurrence of these different facies in the same depth window is contrary to the common thought that changes in bathymetry should be reflected in facies changes. The studied reef systems therefore show aspects of random and ordered facies distribution with respect to water depth. A satellite derived environmental facies map generated by an image analysis algorithm indicates that environmental facies distribution is mainly controlled by water depth, density of seagrass cover and coral abundance. The sand apron can be subdivided into three environmental facies with no, sparse and dense seagrass cover. The deeper water zone can be separated into shallow and deep subtidal parts of lagoons and platform margins. In the lagoon, satellite derived environmental facies directly correlated with sedimentary facies. No direct correlation of environmental facies to sedimentary facies was possible in the sand apron due to the heterogeneity and complexity of the environment. However, the mean sediment grain size is significantly smaller in areas of the sand apron colonized by dense seagrass. This study aims to contribute towards a better understanding of modern equatorial Southeast Asian carbonate systems, delineate modern carbonate facies based on sediment texture and composition with the aid of multivariate statistical analysis combined with statistic based satellite mapping, and give insights regarding the correlation between depositional facies and water depth.
Engineered nanoparticles interact with nutrients to intensify eutrophication in a wetland ecosystem experiment
Authors: Simonin Marie , Colman Benjamin P. , Anderson Steven M. , King Ryan S. , Ruis Matthew T. , Avellan Astrid , Bergemann Christina M. , Perrotta Brittany G. , Geitner Nicholas K. , Ho Mengchi , de la Barrera Belen , Unrine Jason M. , Lowry Gregory V. , Richardson Curtis J. , Wiesner Mark R. , Bernhardt Emily S.
Published: June 2018

Despite the rapid rise in diversity and quantities of engineered nanomaterials produced, the impacts of these emerging contaminants on the structure and function of ecosystems have received little attention from ecologists. Moreover, little is known about how manufactured nanomaterials may interact with nutrient pollution in altering ecosystem productivity, despite the recognition that eutrophication is the primary water quality issue in freshwater ecosystems worldwide. In this study, we asked two main questions: (1) To what extent do manufactured nanoparticles affect the biomass and productivity of primary producers in wetland ecosystems? (2) How are these impacts mediated by nutrient pollution? To address these questions, we examined the impacts of a citrate‐coated gold nanoparticle (AuNPs) and of a commercial pesticide containing Cu(OH)2 nanoparticles (CuNPs) on aquatic primary producers under both ambient and enriched nutrient conditions. Wetland mesocosms were exposed repeatedly with low concentrations of nanoparticles and nutrients over the course of a 9‐month experiment in an effort to replicate realistic field exposure scenarios. In the absence of nutrient enrichment, there were no persistent effects of AuNPs or CuNPs on primary producers or ecosystem productivity. However, when combined with nutrient enrichment, both NPs intensified eutrophication. When either of these NPs were added in combination with nutrients, algal blooms persisted for >50 d longer than in the nutrient‐only treatment. In the AuNP treatment, this shift from clear waters to turbid waters led to large declines in both macrophyte growth and rates of ecosystem gross primary productivity (average reduction of 52% ± 6% and 92% ± 5%, respectively) during the summer. Our results suggest that nutrient status greatly influences the ecosystem‐scale impact of two emerging contaminants and that synthetic chemicals may be playing an under‐appreciated role in the global trends of increasing eutrophication. We provide evidence here that chronic exposure to Au and Cu(OH)2 nanoparticles at low concentrations can intensify eutrophication of wetlands and promote the occurrence of algal blooms.
Forest restoration as a strategy to mitigate climate impacts on wildfire, vegetation, and water in semiarid forests
Authors: O'Donnell Frances C. , Flatley William T. , Springer Abraham E. , Fulé Peter Z.
Published: June 2018

Climate change and wildfire are interacting to drive vegetation change and potentially reduce water quantity and quality in the southwestern United States, Forest restoration is a management approach that could mitigate some of these negative outcomes. However, little information exists on how restoration combined with climate change might influence hydrology across large forest landscapes that incorporate multiple vegetation types and complex fire regimes. We combined spatially explicit vegetation and fire modeling with statistical water and sediment yield models for a large forested landscape (335,000 ha) on the Kaibab Plateau in northern Arizona, USA. Our objective was to assess the impacts of climate change and forest restoration on the future fire regime, forest vegetation, and watershed outputs. Our model results predict that the combination of climate change and high‐severity fire will drive forest turnover, biomass declines, and compositional change in future forests. Restoration treatments may reduce the area burned in high‐severity fires and reduce conversions from forested to non‐forested conditions. Even though mid‐elevation forests are the targets of restoration, the treatments are expected to delay the decline of high‐elevation spruce–fir, aspen, and mixed conifer forests by reducing the occurrence of high‐severity fires that may spread across ecoregions. We estimate that climate‐induced vegetation changes will result in annual runoff declines of up to 10%, while restoration reduced or reversed this decline. The hydrologic model suggests that mid‐elevation forests, which are the targets of restoration treatments, provide around 80% of runoff in this system and the conservation of mid‐ to high‐elevation forests types provides the greatest benefit in terms of water conservation. We also predict that restoration treatments will conserve water quality by reducing patches of high‐severity fire that are associated with high sediment yield. Restoration treatments are a management strategy that may reduce undesirable outcomes for multiple ecosystem services.