bluuebunny/crossref_metadata_2025 huggingface dataset:
Vigas de concreto armado reforçadas à flexão com barras de aço e FRP no cobrimento do concreto
Authors: Melo Renan Henrique de , Teixeira Ana Maria Abreu Jorge , Carneiro Luiz Antonio Vieira
Published: August 2019

Este trabalho tem por objetivo apresentar um método teórico de previsão do momento fletor e da flecha de ruptura de vigas de concreto armado reforçadas à flexão com o uso da técnica da inserção de barras no cobrimento do concreto. Esta técnica é conhecida como a técnica NSM (Near Surface Mounted). No presente trabalho foram utilizadas barras de polímero reforçado com fibras (FRP). Os resultados teóricos foram comparados com os resultados experimentais disponíveis na literatura. Todas as vigas de concreto armado foram submetidas à flexão em quatro pontos. Os parâmetros considerados no método proposto foram as dimensões e taxas de armaduras internas das vigas, a resistência do concreto à compressão, a taxa e o tipo da armadura de reforço, o tipo de cola e o comprimento colado da barra de FRP. Foram analisadas vigas armadas com barras de CFRP, GFRP e aço. Os resultados teóricos obtidos apresentam uma boa aproximação com os resultados experimentais, indicando que a teoria da flexão simples pode ser utilizada para obtenção de valores razoáveis e a favor da segurança de momento fletor e flecha de ruptura de vigas retangulares reforçadas à flexão pela técnica NSM.
Differential expression of AtWAKL10 in response to nitric oxide suggests a putative role in biotic and abiotic stress responses
Authors: Bot Phearom , Mun Bong-Gyu , Imran Qari Muhammad , Hussain Adil , Lee Sang-Uk , Loake Gary , Yun Byung-Wook
Published: August 2019

Plant defense against pathogens and abiotic stresses is regulated differentially by communicating signal transduction pathways in which nitric oxide (NO) plays a key role. Here, we show the biological role of Arabidopsis thaliana wall-associated kinase (AtWAK) Like10 (AtWAKL10) that exhibits greater than a 100-fold change in transcript accumulation in response to the NO donor S-nitroso-L-cysteine (CysNO), identified from high throughput RNA-seq based transcriptome analysis. Loss of AtWAKL10 function showed a similar phenotype to wild type (WT) with, however, less branching. The growth of atwakl10 on media supplemented with oxidative or nitrosative stress resulted in differential results with improved growth following treatment with CysNO but reduced growth in response to S-nitrosoglutatione (GSNO) and methyl-viologen. Further, atwakl10 plants exhibited increased susceptibility to virulent Pseudomonas syringae pv tomato (Pst) DC3000 with a significant increase in pathogen growth and decrease in PR1 transcript accumulation compared to WT overtime. Similar results were found in response to Pst DC3000 avrB, resulting in increased cell death as shown by increased electrolyte leakage in atwakl10. Furthermore, atwakl10 also showed increased reactive oxygen species accumulation following Pst DC3000 avrB inoculation. Promoter analysis of AtWAKL10 showed transcription factor (TF) binding sites for biotic and abiotic stress-related TFs. Further investigation into the role of AtWAKL10 in abiotic stresses showed that following two weeks water-withholding drought condition most of the atwakl10 plants got wilted; however, the majority (60%) of these plants recovered following re-watering. In contrast, in response to salinity stress, atwakl10 showed reduced germination under 150 mM salt stress compared to WT, suggesting that NO-induced AtWAKL10 differentially regulates different abiotic stresses. Taken together, this study further elucidates the importance of NO-induced changes in gene expression and their role in plant biotic and abiotic stress tolerance.
Paranoia and conspiracy: group cohesion increases harmful intent attribution in the Trust Game
Authors: Greenburgh Anna , Bell Vaughan , Raihani Nichola
Published: August 2019

Current theories argue that hyper-sensitisation of social threat perception is central to paranoia. Affected people often also report misperceptions of group cohesion (conspiracy) but little is known about the cognitive mechanisms underpinning this conspiracy thinking in live interactions. In a pre-registered experimental study, we used a large-scale game theory approach (N > 1,000) to test whether the social cohesion of an opposing group affects paranoid attributions in a mixed online and lab-based sample. Participants spanning the full population distribution of paranoia played as proposers in a modified Trust Game: they were allocated a bonus and chose how much money to send to a pair of responders which was quadrupled before reaching these responders. Responders decided how much to return to the proposers through the same process. Participants played in one of two conditions: against a cohesive group who communicated and arrived at a joint decision, or a non-cohesive group who made independent decisions. After the exchange, proposers rated the extent to which the responders’ decisions were driven by (i) self-interest and (ii) intent to harm. Although the true motives are ambiguous, cohesive responders were reliably rated by participants as being more strongly motivated by intent to harm, indicating that group cohesion affects social threat perception. Highly paranoid participants attributed harmful intent more strongly overall but were equally reactive to social cohesion as other participants. This suggests that paranoia involves a generally lowered threshold for social threat detection but with an intact sensitivity for cohesion-related group characteristics.
Random allogeneic blood transfusion in pigs: characterisation of a novel experimental model
Authors: Ziebart Alexander , Schaefer Moritz M. , Thomas Rainer , Kamuf Jens , Garcia-Bardon Andreas , Möllmann Christian , Ruemmler Robert , Heid Florian , Schad Arno , Hartmann Erik K.
Published: August 2019

Background

Organ cross-talk describes interactions between a primary affected organ and a secondarily injured remote organ, particularly in lung-brain interactions. A common theory is the systemic distribution of inflammatory mediators that are released by the affected organ and transferred through the bloodstream. The present study characterises the baseline immunogenic effects of a novel experimental model of random allogeneic blood transfusion in pigs designed to analyse the role of the bloodstream in organ cross-talk.

Methods

After approval of the State and Institutional Animal Care Committee, 20 anesthetized pig were randomized in a donor and an acceptor (eachn = 8): the acceptor animals each received high-volume whole blood transfusion from the donor (35–40 ml kg−1). Four animals received balanced electrolyte solution instead of blood transfusion (control group;n = 4). Afterwards the animals underwent extended cardiorespiratory monitoring for eight hours. Post mortem assessment included pulmonary, cerebral and systemic mediators of early inflammatory response (IL-6, TNF-alpha, iNOS), wet to dry ratio, and lung histology.

Results

No adverse events or incompatibilities occurred during the blood transfusion procedures. Systemic cytokine levels and pulmonary function were unaffected. Lung histopathology scoring did not display relevant intergroup differences. Neither within the lung nor within the brain an up-regulation of inflammatory mediators was detected. High volume random allogeneic blood transfusion in pigs neither impaired pulmonary integrity nor induced systemic, lung, or brain inflammatory response.

Conclusion

This approach can represent a novel experimental model to characterize the blood-bound transmission in remote organ injury.
Unusual Effects of Intramolecular Hydrogen Bonds and Dipole Interaction on FTIR and NMR of Some Imines
Authors: Bin Selim Elham Abdalrahem , Al–Douh Mohammed Hadi
Published: August 2019

Unusual effects of intramolecular hydrogen bonds and dipole interactions are investigated using FTIR, NMR and X-Ray crystallography analyses of some imines. These phenomena affect both FTIR absorptions and chemical shifts.
Effects of Spatial Arrangements and Fertilizers on Productivity in Maize (Zea mays) and Spinach (Celosia argentea) Intercrop
Authors: Olajide Olufunke Olubunmi
Published: August 2019

Maize production falls short of demands in the world because of continuous cropping of a land area, which result into loss of natural soil fertility and decline in yield. This study was undertaken to investigate the performance of maize to organic and inorganic fertilizer and to ascertain spacing for maize-spinach intercrop. The experiment was conducted at the National Horticultural Research Institute, Ibadan. The nutrient sources were farmyard organic manure (derived from household waste materials), and inorganic fertilizer (NPK 15:15:15). These soil nutrient sources were applied at the rate of 100Kg N/ha. The plant spacing used for the maize/spinach intercrop include; 75 x 50 cm, 75 x 75 cm, 75 x 25 cm-sole maize and 25 x 10 cm-sole spinach. Data collected were; plant height, number of leaves, stem girth, leaf area, and yield per cob and fresh weight of spinach. All data were analyzed using the Analysis of variance (ANOVA) and means separated by the least significant difference at 5% probability (LSD, 0.05). F1T1 and F2T4 produced better values for growth and yield parameters than other treatments. The highest value for fresh weight of spinach was obtained at F2T2 (9.30Kg).The results suggested that the application of NPK fertilizer was the best nutrient source for maize production and maize-spinach intercrop should be planted at either 75 x 50 cm spacing, although organic fertilizer is environmental friendly, cheaper and release nutrients contents are slowly, store longer in the soil, thus subsequent planting can still benefit already from previous application.
Antimicrobial Resistance of Neisseria gonorrhoeae Isolated from Out Patients Presenting with Urethral and Vaginal Discharges at Mbarara Regional Referral Hospital
Authors: Owokuhaisa Judith , Bazira Joel
Published: August 2019

Background: Gonococcus is one of the most common sexually transmitted diseases in developing countries and it has become a global health burden, hence a need for effective treatment. However, there is growing trend of antimicrobial resistant strains, in many parts of the world, to the previously effective antimicrobials thus creating serious health concerns.

Setting: Mbarara Regional Referral Hospital -South-Western Uganda.

Objectives: 1) To determine the prevalence of gonococcus among out patients presenting with urethral and vaginal discharges at MRRH.

2) To determine the level of antimicrobial resistance of gonococcus based on phenotypic methods at MRRH.

Design: The study was cross sectional and enrolled 189 participants presenting with urethral and vaginal discharges. The urethral and endo cervical swab samples collected were cultured on Chocolate media supplemented with 5%-10% carbondioxide in candle jar (inoculated plates were placed in a jar and a burning candle placed in the same jar, then closed, by the time the candle went off, that 5%-10% carbondioxide atmosphere would have been created). Isolates obtained were identified according to the laboratory standard operating procedures. Drug Sensitivity Test (DST) on confirmed Neisseria gonorrheae isolates was performed using the Kirby Bauer technique. The colonies of the test organism were emulsified in peptone water and then inoculated on prepared sterile chocolate agar and the following discs were applied to it (Ceftriaxone discs (30µg), Erythromycin (15ug), Ciprofloxacin (10ug) and Penicillin (10IU). The plates were incubated at 37°C for 24- 48 hours under 5% carbon dioxide atmospheres. The Zone of inhibition was seen around an antibiotic disc to which the organism was sensitive.

Results: Out of the 189 participants whose urethral swabs and Endo cervical swabs were cultured, 89 were positive cultures (47%), out of which 25 (28%) were found to have gonococcal infection, 64 (72%) patients had other micro-organisms. The prevalence of Neisseria Gonorrhoeae was 13%. In total, 4% of the isolates were resistant to Ceftriaxone, 28% to Ciprofloxacin, 68% to Erythromycin and 80% to Penicillin. A high percentage of resistance was observed against Penicillin (80%) and Erythromycin (68%).

Conclusion: Adults aged 18 years and above who present at Mbarara Regional Referral Hospital with urethral or vaginal discharges are more likely to have a Neisseria gonorrhoeae which is resistant to Penicillin and Erythromycin.
New Encryption Strategy of Photonic Crystals with Bilayer Inverse Heterostructure Guided from Transparency Response
Authors: Qi Yong , Chu Lin , Niu Wenbin , Tang Bingtao , Wu Suli , Ma Wei , Zhang Shufen
Published: August 2019

Combining functional response materials into colloidal photonic crystals is an accepted encryption strategy for information security. Here, bilayer inverse heterostructure photonic crystals that enable instantaneously transparentizing of the top layer and simultaneously releasing the reflected light of the bottom layer when exposed to ethanol are reported. The transition can quickly return to its original state after the evaporation of ethanol. In addition, the bilayer film is responsive to water, which shows redshift of the bandgap position. The mechanism of the design involves optical scattering and diffraction in the fabricated periodic nanostructures and uses the infiltration and capillary evaporation of fluids with low surface tension to realize the spectral diversity of reflectance. The effects of scattering and color superposition of the upper layer can be obliterated and re‐established for the fact of the infiltration and capillary evaporation of fluids with low surface tension; meanwhile, it provisionally displays the pattern of the bottom layer. Multiple reversible ways to hide and display information could be easily realized by these characteristics. Reconfigurable bilayer inverse heterostructure photonic crystals simultaneously provide a simple and sensitive optical technique for investigating the intriguing encryption effects at the nanoscale.
Rational Engineering of Multilayered Co3O4/ZnO Nanocatalysts through Chemical Transformations from Matryoshka‐Type ZIFs
Authors: Huang Zhongliang , Fan Longlong , Zhao Feigang , Chen Bin , Xu Kaiji , Zhou Shu‐Feng , Zhang Jinli , Li Qingbiao , Hua Dan , Zhan Guowu
Published: August 2019

Hybrid metal oxides with multilayered structures exhibit unique physical and chemical properties, particularly important to heterogeneous catalysis. However, regulations of morphology, spatial location, and shell numbers of the hybrid metal oxides still remain a challenge. Herein, binary Co3O4/ZnO nanocages with multilayered structures (up to eight layers) are prepared via chemical transformation from diverse Matryoshka‐type zeolitic imidazolate frameworks (ZIFs) via a straightforward and scalable calcination method. More importantly, the obtained ZIF‐derived metal oxides (ZDMOs) with versatile layer numbers exhibit remarkable catalytic activity for both gas‐phase CO oxidation and CO2 hydrogenation reactions, which are directly related to the sophisticated shell numbers (i.e., Co3O4‐terminated layers or ZnO‐terminated layers). Particularly, in situ reflectance infrared Fourier transform spectroscopy (DRIFTS) results indicate that the promotional effects of the multilayered structures indeed exist in CO2 hydrogenation, wherein the key reaction intermediates are quite different for five‐layer and six‐layer ZDMOs. For instance, *HCOO is the predominant intermediate over the six‐layer ZDMO; on the contrary, *H3CO is the crucial species over the five‐layer ZDMO. The ZnO/Co3O4 interface should be the active sites for CO2 hydrogenation to *HCOO and *H3CO species, which are ultimately converted to the products (CH4 or methanol). Accordingly, the work here provides a convenient way to facilely engineer multilayered Co3O4/ZnO nanocomposites with precisely controlled shell numbers for heterogeneous catalysis applications.
Engineering Symmetry‐Breaking Nanocrescent Arrays for Nanolasing
Authors: Lin Yuanhai , Wang Danqing , Hu Jingtian , Liu Jianxi , Wang Weijia , Guan Jun , Schaller Richard D. , Odom Teri W.
Published: August 2019

This paper describes a symmetry‐breaking plasmonic lattice structure that can support narrow resonances as optical feedback for nanolasing. A scalable technique is developed to fabricate nanocrescent arrays with low‐structural symmetry unit cells to achieve in‐plane quadrupolar lattice plasmon modes. These lattice plasmons with extremely narrow linewidths preserve nonzero net dipole moments under normal excitation. Ultrafast band‐edge lasing can be switched on and off by changing the polarization of the incident pump light. The quadrupolar lattice plasmon lasing process is simulated with a semi‐quantum model and the sharp tips on the nanocrescents accelerate the lasing buildup process and enhance stimulated emission.
Liquid Assembly of Floating Nanomaterial Sheets for Transparent Electronics
Authors: Su Zongming , Yu Henry S. C. , Zhang Xiaosheng , Brugger Juergen , Zhang Haixia
Published: August 2019

A novel pattern strategy of a nanomaterial network that can self‐assemble onto prepatterned soft substrate to realize ultra‐transparent electronics is presented. The approach detailed is based on the combination of nanomaterials' self‐assembly at the water–air interface to form nanomaterial networks and the breakage phenomenon of water–nanomaterial membranes to form designed patterns. With the comprehensive investigation of this phenomenon, nanomaterial networks are manipulated to attach to prepatterned sidewalls. This leads to a remarkable transparency improvement without conductive property decline. Three 1D nanomaterials with various geometries are demonstrated to verify the universal feature of this pattern strategy, including silver nanowire (AgNW), carbon nanotube, and zinc oxide nanowire. Furthermore, sequential layer‐by‐layer deposition of several 1D nanomaterials has also been demonstrated by using the proposed approach, revealing an attractive potential of multiple‐junction transparent electronics. The fabricated micro‐grid structure of AgNWs with a line width of 5 µm and pitch of 150 µm has a sheet resistance of 37.88 Ω sq−1 and an optical transmittance of 86.06%. This fabrication strategy opens up opportunities for different nanomaterials in many transparent and wearable applications.
Terahertz Time‐Domain Spectroscopy and Near‐Field Microscopy of Transparent Silver Nanowire Networks
Authors: van Hoof Niels , Parente Matteo , Baldi Andrea , Rivas Jaime Gómez
Published: August 2019

Transparent conductive layers are key components of optoelectronic devices. Here, a polyol method is used to synthesize large quantities of monodisperse silver nanowires (AgNWs) and these are used to fabricate transparent conducting networks over large areas. The optical extinction and terahertz (THz) conductance of these networks are simultaneously investigated, using optical and THz spectroscopy, and THz near‐field microscopy. The combination of optical and THz measurements allows the identification of transparent regions with high conductance. The THz near‐field measurements reveal local variations in the THz transmission and conductance that are averaged in far‐field measurements. These results demonstrate that THz near‐field microscopy is a powerful tool for the quantitative investigation of new conductive transparent electrodes.
In Vivo Editing of Macrophages through Systemic Delivery of CRISPR‐Cas9‐Ribonucleoprotein‐Nanoparticle Nanoassemblies
Authors: Lee Yi‐Wei , Mout Rubul , Luther David C. , Liu Yuanchang , Castellanos‐García Laura , Burnside Amy S. , Ray Moumita , Tonga Gulen Yeşilbag , Hardie Joseph , Nagaraj Harini , Das Riddha , Phillips Erin L. , Tay Tristan , Vachet Richard W. , Rotello Vincent M.
Published: August 2019

Macrophages are key effectors of host defense and metabolism, making them promising targets for transient genetic therapy. Gene editing through the delivery of Cas9‐ribonucleoprotein (RNP) provides multiple advantages over gene delivery–based strategies for introducing CRISPR machinery to the cell. There are, however, significant physiological, cellular, and intracellular barriers to the effective delivery of the Cas9 protein and guide RNA (sgRNA) that have to date, restricted in vivo Cas9 protein–based approaches to local/topical delivery applications. Described herein is a new nanoassembled platform featuring coengineered nanoparticles and Cas9 protein that has been developed to provide efficient Cas9‐sgRNA delivery and concomitant CRISPR editing through systemic tail‐vein injection into mice, achieving >8% gene editing efficiency in macrophages of the liver and spleen.
Secreted Protein Acidic and Cysteine Rich (SPARC) Regulates the Pathological Response to Ischemic Insults and Represents a Promising Therapeutic Target for Stroke Treatment
Authors: Zhou Yu , Peng Jing , Cheng Lamei , Peng Yong , Zhang Mingming , Liu Min , Avery Jonathan , Zhou Jiangbing , Jiang Yugang
Published: August 2019

Secreted protein acidic and cysteine rich (SPARC) is a nonstructural, multifunctional matricellular protein involved in tissue development, extracellular matrix, and immune response. In this study, by using mice deficient in SPARC, the role of SPARC in the pathogenesis of ischemic stroke is characterized. It is found that, compared to the wild‐type mice, SPARC deficient mice demonstrated 48.3% reduction in cerebral infarction after ischemia insult. Mechanistically, it is shown that SPARC deficiency significantly reduces ischemia induced cellular apoptosis, diminishes inflammatory response in the ischemic area as well as in the circulatory system, and enhances the integrity of the blood–brain barrier. It is further assessed if SPARC could be targeted for stroke treatment through intraventricular or intravenous administration of SPARC neutralizing antibody. It is found that delivery of SPARC antibody through either route effectively reduces ischemia‐induced infarction. Taken together, the study suggests that SPARC plays an important role in the pathological response to ischemic insults, and represents a promising therapeutic target for clinical management of stroke.
3D geometric morphometric analysis of variation in the human lumbar spine
Authors: Lois Zlolniski Stephanie , Torres‐Tamayo Nicole , García‐Martínez Daniel , Blanco‐Pérez Esther , Mata‐Escolano Federico , Barash Alon , Nalla Shahed , Martelli Sandra , Sanchis‐Gimeno Juan A. , Bastir Markus
Published: August 2019

Objectives

The shape of the human lumbar spine is considered to be a consequence of erect posture. In addition, several other factors such as sexual dimorphism and variation in genetic backgrounds also influence lumbar vertebral morphology. Here we use 3D geometric morphometrics (GM) to analyze the 3D morphology of the lumbar spine in different human populations, exploring those potential causes of variation.

Material and methods

We collected 390 (semi) landmarks from 3D models of the CT scans of lumbar spines of seven males and nine females from a Mediterranean population (Spain, Israel) and seven males and either females from a South African population for geometric morphometric (GM) analysis. We carried out Generalized Procrustes Analysis, Principal Components, and Regression analyses to evaluate shape variation; and complemented these analyses with the Cobb Method.

Results

The Mediterranean sample was considerably more lordotic than the South African sample. In both populations, female lumbar spines showed proportionally narrower and more craniocaudally elongated lumbar segments than in males. In addition, the point of maximum curvature in females tended to be located more inferiorly than in males.

Discussion

Our results show that sexual dimorphism is an important factor of lumbar spine variation that mainly affects features of lumbar spine robustness (height proportions) and the structure—but not the degree—of its curvature. Differences in lordosis, however, are clearer at the inter‐population level. This reflects previous conflicting studies casting doubts on pregnancy as an adaptive factor influencing lordosis. Other factors, for example, shape of the individual lumbar vertebrae and intervertebral discs and their relative proportions within the lumbar spine should be considered when exploring variation in vertebral column morphology.
Exceeding Metal Capacity in Sandwich Complexes: Ligand‐Unsupported Docking of Extra Metal Moieties at Edges of a Metal Sheet Sandwich Complex
Authors: Ishikawa Tomoko , Kawamura Akino , Sugawa Tsuyoshi , Moridaira Risako , Yamamoto Koji , Murahashi Tetsuro
Published: August 2019

The ligand‐unsupported accommodation of extra metal moieties in a sandwich complex is reported. Although it has been considered that the metal‐capacity of a metal sheet sandwich complex is strictly limited by the size of cyclic unsaturated hydrocarbon ligands, the M−M edge bonds in a metal sheet sandwich complex provide a ligand‐unsupported docking site for extra metal moieties, allowing expansion of metal‐capacity in sandwich complexes. The metal sheet sandwich complex [Pd4(μ4‐C8H8)(μ4‐C9H9)]+, in which the ligand‐based metal capacity is full in terms of the usage of all C=C moieties of the smaller carbocyclic ligand C8H8 in coordination, can accommodate extra M0{P(OPh)3}2 (M=Pd, Pt) moieties without coordinative assistance by either the C9H9 or the C8H8 ligand.
Access to Aryl‐Naphthaquinone Atropisomers by Phosphine‐Catalyzed Atroposelective (4+2) Annulations of δ‐Acetoxy Allenoates with 2‐Hydroxyquinone Derivatives
Authors: Chen Xin , Gao Dingding , Wang Dong , Xu Tong , Liu Wei , Tian Ping , Tong Xiaofeng
Published: August 2019

Although asymmetric phosphine catalysis is a powerful tool for the construction of various chiral carbon centers, its synthetic potential toward an enantioenriched atropisomer has not been explored yet. Reported herein is a phosphine‐catalyzed atroposelective (4+2) annulation of δ‐acetoxy allenoates and 2‐hydroxyquinone derivatives. The reaction provides expedient access to aryl‐naphthaquinone atropisomers by the de novo construction of a benzene ring. The two functionalities of the catalyst, a tertiary phosphine (Lewis base) and a tertiary amine (Brønsted base), cooperatively enable this process with high regio‐ and enantioselectivities.
NHC‐Coordinated Diphosphene‐Stabilized Gold(I) Hydride and Its Reversible Conversion to Gold(I) Formate with CO2
Authors: Dhara Debabrata , Das Shubhajit , Pati Swapan K. , Scheschkewitz David , Chandrasekhar Vadapalli , Jana Anukul
Published: August 2019

An NHC‐coordinated diphosphene is employed as ligand for the synthesis of a hydrocarbon‐soluble monomeric AuI hydride, which readily adds CO2 at room temperature yielding the corresponding AuI formate. The reversible reaction can be expedited by the addition of NHC, which induces β‐hydride shift and the removal of CO2 from equilibrium through the formation of an NHC‐CO2 adduct. The AuI formate is alternatively formed by dehydrogenative coupling of the AuI hydride with formic acid (HCO2H), thus in total establishing a reaction sequence for the AuI hydride mediated dehydrogenation of HCO2H as chemical hydrogen storage material.
Reversible Formation of a Light‐Responsive Catalyst by Utilizing Intermolecular Cooperative Effects
Authors: Ren Chloe Z.‐J. , Solís Muñana Pablo , Dupont Julien , Zhou Silvia Siru , Chen Jack L.‐Y.
Published: August 2019

A photoresponsive system where structure formation is coupled to catalytic activity is presented. The observed catalytic activity is reliant on intermolecular cooperative effects that are present when amphiphiles assemble into vesicular structures. Photoresponsive units within the amphiphilic pre‐catalysts allow for switching between assembled and disassembled states, thereby modulating the catalytic activity. The ability to reversibly form cooperative catalysts within a dynamic self‐assembled system represents a conceptually new tool for the design of complex artificial systems in water.
Cooperative Tertiary Amine/Chiral Iridium Complex Catalyzed Asymmetric [4+3] and [3+3] Annulation Reactions
Authors: Chen Zhi‐Chao , Chen Zhi , Yang Zhen‐Hong , Guo Li , Du Wei , Chen Ying‐Chun
Published: August 2019

Asymmetric reactions merging organocatalysis and metal catalysis significantly broaden the scope of organic synthesis. Nevertheless, the accomplishment of stereoselective annulations combining two types of dipole species, independently generated from the activations of organocatalysts and metal complexes, still remains as a challenging task. Now, Morita–Baylis–Hillman carbonates from isatins and carbamate‐functionalized allyl carbonates could be chemoselectively activated by achiral Lewis basic tertiary amines and chiral iridium complexes. The zwitterionic allylic ylides and 1,4‐π‐allyliridium dipoles formed in situ are assembled in a highly stereoselective [4+3] annulation pattern. Similar cooperative catalytic strategy could be applied for the reactions of Morita–Baylis–Hillman carbonates and vinyl aziridines, furnishing an asymmetric [3+3] annulation reaction also with excellent stereocontrol.
High‐Precision Size Recognition and Separation in Synthetic 1D Nanochannels
Authors: Wang Ping , Chen Xinyi , Jiang Qiuhong , Addicoat Matthew , Huang Ning , Dalapati Sasanka , Heine Thomas , Huo Fengwei , Jiang Donglin
Published: August 2019

Covalent organic frameworks (COFs) allow elaborate manufacture of ordered one‐dimensional channels in the crystal. We defined a superlattice of COFs by engineering channels with a persistent triangular shape and discrete pore size. We observed a size‐recognition regime that is different from the characteristic adsorption of COFs, whereby pore windows and walls were cooperative so that triangular apertures sorted molecules of one‐atom difference and notch nanogrooves confined them into single‐file molecular chains. The recognition and confinement were accurately described by sensitive spectroscopy and femtosecond dynamic simulations. The resulting COFs enabled instantaneous separation of mixtures at ambient temperature and pressure. This study offers an approach to merge precise recognition, selective transport, and instant separation in synthetic 1D channels.
Facile strategy and mechanism of greatly toughening epoxy resin using polyethersulfone through controlling phase separation with microwave‐assisted thermal curing technique
Authors: Deng Huiyuan , Yuan Li , Gu Aijuan , Liang Guozheng
Published: August 2019

Toughening has been the essential issue for developing high‐performance thermosetting resins. Herein, starting from polyethersulfone (PES) and bisphenol A epoxy resin (EP), a facile strategy is developed to prepare tough resins through controlling phase structure with microwave‐assisted thermal curing. PES/EP resins cured with the assistance of microwave curing (m‐PES/EP) have two major differences compared with those using traditional heat curing (t‐PES/EP), one is high degree of phase separation, and the other is phase separation mechanism. Initial phase separation of all t‐PES/EP resins follows spinodal decomposition mechanism, while those of m‐PES/EP systems with 8 wt% and 18 wt% of PES follow nucleation and growth mechanism. These differences are derived from the fact that microwave curing has much faster phase separation rate and curing reaction rate than thermal curing owing to the higher thermal effect. Differences in phase structure bring different macro performances, and m‐PES/EP systems have higher impact strengths, fracture toughnesses, and flexural strengths than t‐PES/EP resins. This investigation provides a facial and effective way of developing higher performance thermoplastic/thermosetting resin system through controlling phase structure. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2020,137, 48394.
Preparation and mechanism analysis of morphology‐controlled cellulose nanocrystals via compound enzymatic hydrolysis of eucalyptus pulp
Authors: Tong Xin , Shen Wenhao , Chen Xiaoquan , Jia Mengyu , Roux Jean‐Claude
Published: August 2019

First, making from eucalyptus cellulose fiber, the influences of different compound enzymolysis conditions on the morphology of cellulose nanocrystals (CNCs) were studied. Under the actions of the compound enzyme composed of cellulase and xylanase with the concentration ratio of 9:1, total enzyme concentrations of 10 and 500 U mL−1 and the hydrolysis time of 12 and 5 h, the rod‐like CNCs (length 600 nm, width 30 nm) and the spherical CNCs (40 nm) were obtained, respectively. Subsequently, the crystallinities, chemical structures, and thermal stabilities of the rod‐like and spherical CNCs revealed that, the CNCs structures were still similar to those of the eucalyptus cellulose fiber, the thermal decomposition temperatures of the rod‐like and spherical CNCs (345, 343 °C) were a little lower than that of the eucalyptus cellulose fiber (364 °C). Lastly, the control mechanism of CNC morphology by the compound enzymatic hydrolysis was also discussed. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48407.
Solution mixing preparation of PVDF/ZnO polymeric composite films engineered for heterogeneous photocatalysis
Authors: Dossin Zanrosso Crissie , Piazza Diego , Lansarin Marla Azário
Published: August 2019

Despite the efforts of the scientific community, carrying out photocatalyst immobilization so that industrial application of photocatalysis becomes economically feasible is still a challenge to be overcome. In this work, polyvinylidene fluoride (PVDF)/ZnO composites were prepared by solution mixing based on solid knowledge of membrane technology and with the help of a powerful experimental design for systematic evaluation of the interaction among variables. A strategy for variable screening was used, followed by a complete evaluation at two levels, leading to predictive models. As a result, photocatalyst amount, pore agent concentration, and wet thickness were the most significant in the target molecule discoloration. With this, it was possible to obtain a 40 and 186% enhancement in photocatalytic efficiency compared to previous results and simple photolysis, respectively. Finally, the samples were characterized by FTIR‐ATR, XRD, and SEM and chemical, crystalline and morphological differences were observed both with nanoparticle and pore agent incorporation. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48417.
Determining keystone species complexes and macroscopic properties for improving ecosystem‐based conservation practices in coral reefs along the western Caribbean Sea (Mexico and Honduras)
Authors: Hermosillo‐Núñez Brenda B. , Ortiz Marco , Rodríguez‐Zaragoza Fabián A.
Published: August 2019

Coral ecosystems have been subjected to disturbances caused by humans that threaten their health and alter their structure and functioning.

Trophic models were constructed in three coral reef ecosystems along the western Caribbean Sea (Mexico and Honduras) to evaluate the structure, organization, health, and species and functional groups that play keystone roles in these ecosystems.

The quantification of the macroscopic properties showed that Media Luna Reef (Honduras) is a more mature, developed, organized, and healthy ecosystem but, in turn, is less resistant to perturbations.

The outcomes showed that the ecological systems with reduced human disturbances were more mature and healthy. Likewise, the keystone species complexes contributed considerably to the maturity, development, and health of such coral ecosystems.

Several exploited species were integrated into the keystone species complexes, which also would increase resistance against perturbations.

These findings suggest that current fisheries management strategies could be improved within a network context to achieve the sustainable usage of resources and to include management programmes to conserve the current conditions of Media Luna Reef.
Instandsetzung und Teilertüchtigung der Gürtelbrücke B0901 in Wien
Authors: Geier Roman , Wosmik Manfred , Hejda Nikolaus
Published: August 2019

Die Gürtelbrücke (Objekt B0901) – ein hochrangiger Brückenzug in der Stadt Wien, Österreich – wurde in den Jahren 1962 bis 1964 errichtet. Rund 68.000 Fahrzeuge sind täglich auf der Verbindung über den Donaukanal unterwegs. Die Brückenkette wurde zuletzt im Zuge der Verlängerung der U‐Bahn‐Linie U6 Anfang der 1990er Jahre umgebaut. In den vergangenen Jahrzehnten wurden aufgrund der verkehrlichen Bedeutung und zur Vermeidung von Verkehrsbehinderungen durch Bauarbeiten nur punktuelle, unbedingt erforderliche Instandsetzungsarbeiten durchgeführt.

Die hohe Beanspruchung und der damit verbundene Erhaltungszustand erforderten aber nach 50 Jahren der Nutzung eine umfassende Brückeninstandsetzung mit einer abschnittsweisen Teilertüchtigung. Durch die Vielzahl an unterschiedlichen Brückensystemen und Baustoffen der Brückenkette waren umfangreiche statisch‐konstruktive und Verkehrsmaßnahmen zur Erhaltung dieser wesentlichen Verbindung erforderlich. Die im Herbst 2012 begonnenen Bauarbeiten an der Gürtelbrücke konnten trotz widrigster Umstände bei der Bauausführung im Herbst 2015 plangemäß abgeschlossen werden. In der vorliegenden Veröffentlichung sollen die Besonderheiten aus der Planungs‐ und Bauphase dargestellt werden, um aus diesen Erfahrungen bei ähnlichen Projekten Nutzen ziehen zu können.
Greenwashing and environmental communication: Effects on stakeholders' perceptions
Authors: Torelli Riccardo , Balluchi Federica , Lazzini Arianna
Published: August 2019

Since the first Earth Day in the 1970s, corporate environmental performance has increased dramatically, and cases of greenwashing have increased sharply. The term greenwash refers to a variety of different misleading communications that aim to form overly positive beliefs among stakeholders about a company's environmental practices. The growing number of corporate social responsibility claims, whether founded or not, creates difficulties for stakeholders in distinguishing between truly positive business performance and companies that only appear to embrace a model of sustainable development. In this context, through the lens of legitimacy and signalling theory, we intend to understand and assess the different influences that various types of misleading communications about environmental issues have on stakeholders' perceptions of corporate environmental responsibility and greenwashing. Stakeholder responses to an environmental scandal will also be assessed. The hypotheses tested through a four‐for‐two design experiment reveal that different levels of greenwashing have a significantly different influence on stakeholders' perceptions of corporate environmental responsibility and stakeholders' reactions to environmental scandals.
Body cameras don't negatively affect police, civilian interactions
Authors: Sutton Halley
Published: August 2019

Most victims do not notice body cameras on police, and of victims who do notice body cameras, most do not object to being recorded, according to a study conducted by the National Police Federation. According to the study, which recorded 321 interactions between civilians and police officers wearing a body camera, the quality of the interaction did not suffer because of the body camera, even when civilians were aware of the camera.
Properly handling negative values in the calculation of binding constants by physicochemical modeling of spectroscopic titration data
Authors: Kazmierczak Nathanael P. , Vander Griend Douglas A.
Published: August 2019

To implement equilibrium hard‐modeling of spectroscopic titration data, the analyst must make a variety of crucial data processing choices that address negative absorbance and molar absorptivity values. The efficacy of three such methodological options is evaluated via high‐throughput Monte Carlo simulations, root‐mean‐square error surface mapping, and two mathematical theorems. Accuracy of the calculated binding constant values constitutes the key figure of merit used to compare different data analysis approaches. First, using singular value decomposition to filter the raw absorbance data prior to modeling often reduces the number of negative values involved but has little effect on the calculated binding constant despite its ability to address spectrometer noise. Second, both truncation of negative molar absorptivity values and the fast nonnegative least squares algorithms are superior to unconstrained regression because they avoid local minima; however, they introduce bias into the calculated binding constants in the presence of negative baseline offsets. Finally, we establish two theorems showing that negative values are best addressed when all the chemical solutions leading to the raw absorbance data are the result of mixing exactly two distinct stock solutions. This allows the raw absorbance data to be shifted up, eliminating negative baseline offsets, without affecting the concentration matrix, residual matrix, or calculated binding constants. Otherwise, the data cannot be safely upshifted. A comprehensive protocol for analyzing experimental absorbance datasets with is included.
Push–Pull Porphyrins via β‐Pyrrole Functionalization: Evidence of Excited State Events Leading to High‐Potential Charge‐Separated States
Authors: Sekaran Bijesh , Jang Youngwoo , Misra Rajneesh , D'Souza Francis
Published: August 2019

A new set of free‐base and zinc(II)‐metallated, β‐pyrrole‐functionalized unsymmetrical push–pull porphyrins were designed and synthesized via β‐mono‐ and dibrominated tetraphenylporphyrins using Sonogashira cross‐coupling reactions. The ability of donors and acceptors on the push–pull porphyrins to produce high‐potential charge separated states was investigated. The porphyrins were functionalized at the opposite β,β′‐pyrrole positions of porphyrin ring bearing triphenylamine push groups and naphthalimide pull groups. Systematic studies involving optical absorption, steady‐state and time‐resolved emission revealed existence of intramolecular type interactions both in the ground and excited states. The push–pull nature of the molecular systems was supported by frontier orbitals generated on optimized structures, wherein delocalization of HOMO over the push group and LUMO over the pull group connecting the porphyrin π‐system was witnessed. Electrochemical studies were performed to visualize the effect of push and pull groups on the overall redox potentials of the porphyrins. Spectroelectrochemical studies combined with frontier orbitals helped in characterizing the one‐electron oxidized and reduced porphyrins. Finally, by performing transient absorption studies in polar benzonitrile, the ability of push–pull porphyrins to produce charge‐separated states upon photoexcitation was confirmed and the measured rates were in the range of 109 s−1. The lifetime of the final charge separated state was around 5 ns. This study ascertains the importance of push–pull porphyrins in solar energy conversion and diverse optoelectronic applications, for which high‐potential charge‐separated states are warranted.
Donor Strengths Determination of Pnictogen and Chalcogen Ligands by the Huynh Electronic Parameter and Its Correlation to Sigma Hammett Constants
Authors: Teng Qiaoqiao , Ng Ping Siang , Leung Jia Nuo , Huynh Han Vinh
Published: August 2019

The suitability and accuracy of the Huynh electronic parameter (HEP) was further tested to reveal remote substituent effects in pyridines, which are located five or six bonds away from the reporter probe. These values show an excellent correlation to Hammett σ‐constants of the respective substituents with coefficients of R2=0.9856 (σm) and R2=0.9857 (σp). Based on this observation, a methodology for the re‐evaluation of certain Hammett constants with larger uncertainties has been proposed and demonstrated. Moreover, the scope of HEP was extended to various neutral pnictogen and chalcogen donors during which “transphobia effects” were revealed for mixed NHC complexes containing phosphites, arsine and stibine for the first time.
Hierarchical FeCo2S4@FeNi2S4 Core/Shell Nanostructures on Ni Foam for High‐Performance Supercapacitors
Authors: Huang Yunxia , Ge Shuaipeng , Chen Xiaojuan , Xiang Zhongcheng , Zhang Xinran , Zhang Ruoxuan , Cui Yimin
Published: August 2019

The design of electrode materials with rational core/shell structures is promising for improving the electrochemical properties of supercapacitors. Hence, hierarchical FeCo2S4@FeNi2S4 core/shell nanostructures on Ni foam were fabricated by a simple hydrothermal method. Owing to their structure and synergistic effect, they deliver an excellent specific capacitance of 2393 F g−1 at 1 A g−1 and long cycle lifespan as positive electrode materials. An asymmetric supercapacitor device with FeCo2S4@FeNi2S4 as positive electrode and graphene as negative electrode exhibited a specific capacitance of 133.2 F g−1 at 1 A g−1 and a high energy density of 47.37 W h kg−1 at a power density of 800 W kg−1. Moreover, the device showed remarkable cycling stability with 87.0 % specific‐capacitance retention after 5000 cycles at 2 A g−1. These results demonstrate that the hierarchical FeCo2S4@FeNi2S4 core/shell structures have great potential in the field of electrochemical energy storage.
Emergent Self‐Assembly Pathways to Multidimensional Hierarchical Assemblies using a Hetero‐Seeding Approach
Authors: Liu Yin , Gong Yanjun , Guo Yongxian , Xiong Wei , Zhang Yifan , Zhao Jincai , Che Yanke , Manners Ian
Published: August 2019

The controlled formation of complex and functional 1‐, 2‐, and 3D hierarchical assemblies from molecular building blocks represents a key current challenge. Herein, we report the use of a seeded growth approach for a series of perylenediimide‐based molecules (PDIs 1–4) to access otherwise inaccessible self‐assembly pathways that yield complex hierarchical structures. The key to the new approach is to use hetero‐seeds which possess a different composition and morphology from that of the molecular building block. For example, a nanotube seed (from PDI 3) and a microribbon seed (from PDI 4) were found to initiate different self‐assembly pathways for PDI 1, which normally assembles to yield nanocoils. This led to the formation of unprecedented 3D scroll‐like and scarf‐like hierarchical nanostructures, respectively. Also, the hetero‐seeds from PDI 3 initiate hidden self‐assembly pathways of PDI 2 to generate 1D tubular heterojunctions. Significantly, this new strategy offers new opportunities to create emergent and functional hierarchical and complex structures from small molecule precursors.
Potent and Selective Cytotoxic and Anti‐inflammatory Gold(III) Compounds Containing Cyclometalated Phosphine Sulfide Ligands
Authors: Reddy T. Srinivasa , Pooja Deep , Privér Steven H. , Luwor Rodney B. , Mirzadeh Nedaossadat , Ramesan Shwathy , Ramakrishna Sistla , Karri Shailaja , Kuncha Madhusudana , Bhargava Suresh K.
Published: August 2019

Four cycloaurated phosphine sulfide complexes, [Au{κ2‐2‐C6H4P(S)Ph2}2][AuX2] [X=Cl (2), Br (3), I (4)] and [Au{κ2‐2‐C6H4P(S)Ph2}2]PF6 (5), have been prepared and thoroughly characterized. The compounds were found to be stable under physiological‐like conditions and showed excellent cytotoxicity against a broad range of cancer cell lines and remarkable cytotoxicity in 3D tumor spheroids. Mechanistic studies with cervical cancer (HeLa) cells indicated that the cytotoxic effects of the compounds involve the inhibition of thioredoxin reductase and induction of apoptosis through mitochondrial disruption. In vivo experiments in nude mice bearing HeLa xenografts showed that treatment with compounds 4 and 5 resulted in significant inhibition of tumor growth (35.8 and 46.9 %, respectively), better than that of cisplatin (29 %). The newly synthesized gold complexes were also evaluated for their in vitro and in vivo anti‐inflammatory activity through the study of lipopolysaccharide (LPS)‐activated macrophages and carrageenan‐induced hind paw edema in rats, respectively.