bluuebunny/crossref_metadata_2025 huggingface dataset:
Anticancer Potential of Diiron Vinyliminium Complexes
Authors: Rocco Dalila , Batchelor Lucinda K. , Agonigi Gabriele , Braccini Simona , Chiellini Federica , Schoch Silvia , Biver Tarita , Funaioli Tiziana , Zacchini Stefano , Biancalana Lorenzo , Ruggeri Marina , Pampaloni Guido , Dyson Paul J. , Marchetti Fabio
Published: August 2019

Although ferrocene derivatives have attracted considerable attention as possible anticancer agents, the medicinal potential of diiron complexes has remained largely unexplored. Herein, we describe the straightforward multigram‐scale synthesis and the antiproliferative activity of a series of diiron cyclopentadienyl complexes containing bridging vinyliminium ligands. IC50 values in the low‐to‐mid micromolar range were determined against cisplatin sensitive and resistant human ovarian carcinoma (A2780 and A2780cisR) cell lines. Notable selectivity towards the cancerous cells lines compared to the non‐tumoral human embryonic kidney (HEK‐293) cell line was observed for selected compounds. The activity seems to be multimodal, involving reactive oxygen species (ROS) generation and, in some cases, a fragmentation process to afford monoiron derivatives. The large structural variability, amphiphilic character and good stability in aqueous media of the diiron vinyliminium complexes provide favorable properties compared to other widely studied classes of iron‐based anticancer candidates.
Proton Acidity and Proton Mobility in ECR‐40, a Silicoaluminophosphate that Violates Löwenstein's Rule
Authors: Fischer Michael
Published: August 2019

The silicoaluminophosphate zeotype ECR‐40 contains linkages of AlO4 tetrahedra via a common oxygen atom, thereby violating the famous “Löwenstein's rule”. In this work, a combination of static density functional theory (DFT) calculations and DFT‐based ab‐initio molecular dynamics (AIMD) simulations were employed to study the acidity and mobility of protons associated with such unusual linkages. It was found that the Al‐O‐Al linkages are preferentially protonated, as deprotonation causes a local accumulation of negative charge. The protons at these linkages possess a somewhat lower Brønsted acidity than those at Si‐O‐Al links. AIMD simulations for fully hydrated ECR‐40 predicted a partial deprotonation of the Al‐O‐Al linkages, whereas Si‐O‐Al linkages were fully deprotonated. Frequently, a coordination of water molecules to framework Al atoms was observed in the vicinity of the Al‐O‐Al links. Hence, these linkages appear prone to break upon dehydration, potentially explaining why Löwenstein's rule is mostly obeyed in materials formed in aqueous media.
Effect of the Metal within Regioisomeric Paddle‐Wheel‐Type Metal–Organic Frameworks
Authors: Ha Hyeonbin , Kim Youngik , Kim Dopil , Lee Jihyun , Song Yoodae , Kim Suyeon , Park Myung Hwan , Kim Youngjo , Kim Hyungjun , Yoon Minyoung , Kim Min
Published: August 2019

The effect of metal on the degree of flexibility upon evacuation of metal–organic frameworks (MOFs) has been revealed with positional control of the organic functionalities. Although Co‐, Cu‐, and Zn‐based DMOFs (DMOF = DABCO MOF, DABCO = 1,4‐diazabicyclo[2.2.2]octane) with ortho‐ligands (2,3‐NH2Cl) have frameworks that are inflexible upon evacuation, MOFs with para‐ligands (2,5‐NH2Cl) showed different N2 uptake amounts after evacuation by metal exchange. Considering that the structural analyses were not fully sufficiently different to explain the drastic changes in N2 adsorption after evacuation, quantum chemical simulation was explored. A new index (η) was defined to quantify the regularity around the metal based on differences in the oxygen‐metal‐oxygen angles. Within 2,5‐NH2Cl, the η value becomes larger as the metal are varied from Co to Zn. A large η value means that the structures around the metal center are less ordered. These results can be used to explain flexibility changes upon evacuation by altering the metal cation in this regioisomeric system.
Precise Manipulation of Temperature‐Driven Chirality Switching of Molecular Universal Joints through Solvent Mixing
Authors: Fan Chunying , Yao Jiabin , Li Guojuan , Guo Cheng , Wu Wanhua , Su Dan , Zhong Zhihui , Zhou Dayang , Wang Yuliang , Chruma Jason J. , Yang Cheng
Published: August 2019

Invited for the cover of this issue is Cheng Yang and co‐workers at Sichuan University. The image depicts solvent mixing as a precise, but powerful and pervasive method for manipulating the temperature‐driven chirality switching behavior of molecular universal joints. Read the full text of the article at 10.1002/chem.201902676.
Deoxygenative Arylation of Carboxylic Acids by Aryl Migration
Authors: Ruzi Rehanguli , Ma Junyang , Yuan Xiang‐Ai , Wang Wenliang , Wang Shanshan , Zhang Muliang , Dai Jie , Xie Jin , Zhu Chengjian
Published: August 2019

An unprecedented deoxygenative arylation of aromatic carboxylic acids has been achieved, allowing the construction of an enhanced library of unsymmetrical diaryl ketones. The synergistic photoredox catalysis and phosphoranyl radical chemistry allows for precise cleavage of a stronger C−O bond and formation of a weaker C−C bond by 1,5‐aryl migration under mild reaction conditions. This new protocol is independent of substrate redox‐potential, electronic, and substituent effects. It affords a general and promising access to 60 examples of synthetically versatile o‐amino and o‐hydroxy diaryl ketones under redox‐neutral conditions. Furthermore, it also brings one concise route to the total synthesis of quinolone alkaloid, (±)‐yaequinolone A2, and a viridicatin derivative in satisfying yields.
Das Flackern der Blitze
Authors: Feil Sylvia
Published: August 2019

Erstmals wurde das Innere eines Blitzes von einem internationalen Team räumlich und zeitlich hochaufgelöst. Dabei wurden neue Strukturen innerhalb der Gewitterwolke entdeckt, die das mehrfache Entladen, das „Flackern“ der Blitze, erklären.
Pseudospectral Bound and Transition Threshold for the 3D Kolmogorov Flow
Authors: Li Te , Wei Dongyi , Zhang Zhifei
Published: August 2019

In this paper, we study pseudospectral bounds for the linearized operator of the Navier‐Stokes equations around the 3D Kolmogorov flow. Using the pseudospectral bound and the wave operator method introduced in [22], we prove the sharp enhanced dissipation rate for the linearized Navier‐Stokes equations. As an application, we prove that if the initial velocity satisfiesurn:x-wiley:00103640:media:cpa21863:cpa21863-math-0001

(ν the viscosity coefficient) and kf ∈ (0, 1), then the solution does not transition away from the Kolmogorov flow. © 2019 Wiley Periodicals, Inc.
Global Solution for Massive Maxwell‐Klein‐Gordon Equations
Authors: Klainerman Sergiu , Wang Qian , Yang Shiwu
Published: August 2019

We derive the asymptotic properties of the mMKG system (Maxwell coupled with a massive Klein‐Gordon scalar field) in the exterior of the domain of influence of a compact set. This complements the previous well‐known results, restricted to compactly supported initial conditions, based on the so‐called hyperboloidal method. That method takes advantage of the commutation properties of the Maxwell and Klein‐Gordon equations with the generators of the Poincaré group to resolve the difficulties caused by the fact that they have, separately, different asymptotic properties. Though the hyperboloidal method is very robust and applies well to other related systems, it has the well‐known drawback of requiring compactly supported data. In this paper we remove this limitation based on a further extension of the vector field method adapted to the exterior region. Our method applies, in particular, to nontrivial charges. The full problem can then be treated by patching together the new estimates in the exterior with the hyperboloidal ones in the interior. This purely physical space approach introduced here maintains the robust properties of the old method and can thus be applied to other situations such as the coupled Einstein Klein‐Gordon equation. © 2019 Wiley Periodicals, Inc.
High‐Performance Plasma‐Enabled Biorefining of Microalgae to Value‐Added Products
Authors: Zhou Renwu , Zhou Rusen , Zhang Xianhui , Fang Zhi , Wang Xiaoxiang , Speight Robert , Wang Hongxia , Doherty William , Cullen Patrick J. , Ostrikov Kostya (Ken) , Bazaka Kateryna
Published: August 2019

Conversion of renewable biomass by time‐ and energy‐efficient techniques remains an important challenge. Herein, plasma catalytic liquefaction (PCL) is employed to achieve rapid liquefaction of microalgae under mild conditions. The choice of the catalyst affects both the liquefaction efficiency and the yield of products. The acid catalyst is more effective and gave a liquid yield of 73.95 wt % in 3 min, as opposed to 69.80 wt % obtained with the basic catalyst in 7 min. Analyses of the thus‐formed products and the processing environment reveal that the enhanced PCL performance is linked to the rapid increase in temperature under the effect of plasma‐induced electric fields and the generation of large quantities of reactive species. Moreover, the obtained solid residue can be simply upgraded to a carbon product suitable for supercapacitor applications. Therefore, the proposed strategy may provide a new avenue for fast and comprehensive utilization of biomass under benign conditions.
An enhanced anonymous identity‐based key agreement protocol for smart grid advanced metering infrastructure
Authors: Mahmood Khalid , Arshad Jehangir , Chaudhry Shehzad Ashraf , Kumari Saru
Published: August 2019

Sprouting populace mass within the urban areas furnishes critical challenges of providing uninterruptible community services to fulfill the primitive needs of inhabitants in smart cities. Smart cities facilitate and uplift the living standards of inhabitants through various smart systems or infrastructures, and smart grid is one of them. Secure transmission is a key requirement in the advanced metering infrastructure (AMI) of most smart grids, and key establishment cryptographic protocols can be used to achieve such a requirement. Designing efficient and secure key establishment protocols for AMI remains challenging. For example, in this paper, we reveal several weaknesses in the identity‐based key establishment protocol of Mohammadali et al (published in IEEE Trans Smart Grid, 2017), which is based on elliptic curves. We then improve their protocol and prove its security in the random oracle model. We also demonstrate that the improved protocol achieves both anonymity and untraceability, before presenting a comparative summary of the security and computational overheads of the proposed protocol and several other existing protocols.
Selection on tropane alkaloids in native and non‐native populations of Datura stramonium
Authors: Castillo Guillermo , Calahorra‐Oliart Adriana , Núñez‐Farfán Juan , Valverde Pedro L. , Arroyo Juan , Cruz Laura L. , Tapia‐López Rosalinda
Published: August 2019

Theories of plant invasion based on enemy release in a new range assume that selection exerted by specialist herbivores on defence traits should be reduced, absent, or even selected against in the new environment. Here, we measured phenotypic selection on atropine and scopolamine concentration of Datura stramonium in eight native (Mexico) and 14 non‐native (Spain) populations. Native populations produced between 20 and 40 times more alkaloid than non‐native populations (atropine: 2.0171 vs. 0.0458 mg/g; scopolamine: 1.004 vs. 0.0488 mg/g, respectively). Selection on alkaloids was negative for atropine and positive for scopolamine concentration in both ranges. However, the effect sizes of selection gradients were only significant in the native range. Our results support the assumption that the reduction of plant defence in the absence of the plant's natural enemies in invasive ranges is driven by natural selection.
Temporally adaptive acoustic sampling to maximize detection across a suite of focal wildlife species
Authors: Balantic Cathleen , Donovan Therese
Published: August 2019

Acoustic recordings of the environment can produce species presence–absence data for characterizing populations of sound‐producing wildlife over multiple spatial scales. If a species is present at a site but does not vocalize during a scheduled audio recording survey, researchers may incorrectly conclude that the species is absent (“false negative”). The risk of false negatives is compounded when audio devices have sampling constraints, do not record continuously, and must be manually scheduled to operate at pre‐selected times of day, particularly when research programs target multiple species with acoustic availability that varies across temporal conditions.

We developed a temporally adaptive acoustic sampling algorithm to maximize detection probabilities for a suite of focal species amid sampling constraints. The algorithm combines user‐supplied species vocalization models with site‐specific weather forecasts to set an optimized sampling schedule for the following day. To test our algorithm, we simulated hourly vocalization probabilities for a suite of focal species in a hypothetical monitoring area for the year 2016. We conducted a factorial experiment that sampled from the 2016 acoustic environment to compare the probability of acoustic detection by a fixed (stationary) schedule versus a temporally adaptive optimized schedule under several sampling efforts and monitoring durations.

We found that over the course of a study season, the probability of acoustically capturing a focal species (given presence) at least once via automated acoustic monitoring was greater (and acoustic capture occurred earlier in the season) when using the temporally adaptive optimized schedule as compared to a fixed schedule.

The advantages of a temporally adaptive optimized acoustic sampling schedule are magnified when a study duration is short, sampling effort is low, and/or species acoustic availability is minimal. This methodology presents the opportunity to maximize acoustic monitoring sampling efforts amid constraints.
Effect of Catalytically Active Zinc Oxide−Carbon Nanotube Composite on Sensitive Assay of Desloratadine Metabolite
Authors: Ozturk Kubra , Bakirhan Nurgul K. , Ozkan Sibel A. , Uslu Bengi
Published: August 2019

Desloratadine is one of the most effective second‐generation antihistamines and the electrochemical behavior of the active agent of desloratadine was investigated with a new nanosensor designed with the addition of zinc oxide and multiwalled carbon nanotube (ZnO : MWCNT) mixture on glassy carbon (GCE). By investigating and using cyclic, differential pulse and square wave voltammetry techniques with ZnO : MWCNT/GCE, it is planned to obtain information about quantification and mechanism of desloratadine. The efficiency of experimental parameters such as pH, scan rate, accumulation potential and time on the anodic response of desloratadine were studied. Differential pulse voltammetry was selected as assay method and under developed method and optimized conditions, the current showed linear dependence with concentration in the range between 2×10−8 and 8×10−6 M in pH 5.5 acetate buffer. The achieved limits of detection (LOD) and quantification (LOQ) are 0.769 nM and 2.56 nM respectively. Applicability of the methods was demonstrated by their implementation in pharmaceutical dosage forms of desloratadine and the accuracy, precision, selectivity, sensitivity, intra‐day and day‐to‐day reproducibility of the methods were clearly explored. Finally, this sensor was successfully applied on real sample as a selective, simple, reproducible, repeatable an electrochemical sensor.
Mesopore‐controllable Carbon Aerogel and their Highly Loaded PtRu Anode Electrocatalyst for DMFC Applications
Authors: Bong Sungyool , Han Donghoon
Published: August 2019

Catalyst loading and layer thickness are crucial factors to enhance the cell performance and to reduce cost of membrane electrode assemblies (MEAs). Outstanding properties, such as large surface area to disperse metal nanoparticles and sufficient pore volume and size, is needed in utilization of fuel cell. Carbon aerogels are one of the good candidates that meets the above conditions. Those are synthesized by polycondensation reaction of resorcinol and formaldehyde (RF) polymer, supercritical drying to keep pore skeleton structure caused by capillary force and calcination of RF polymer in nitrogen atmosphere to be controllable meso pore (2∼43 nm) as role of support for electric conductor and dispersion of metal nanoparticles. In order to utilization of anode catalyst in direct methanol fuel cell, highly loaded (80 weight percent) platinum and ruthenium onto carbon aerogel are synthesized by Bönnemann colloid method. The single cell test of carbon aerogel supported PtRu anode catalyst is performed and over 40 nm pore sized‐catalysts are the best performance due to sufficient surface area to anchor uniform and small metal nanoparticles and good pathway to drive fuel and outgas even though PtRu nanoparticles are anchored on the outer surface of carbons.
Simultaneous Electroanalysis of Guaiacol and its Analogs Based on their Differential Complexation with α‐Cyclodextrin on Nafion Modified Boron‐doped Diamond Electrode
Authors: Hayes Phyllis E. , Glennon Jeremy D. , Buzid Alyah , Luong John H. T.
Published: August 2019

Guaiacol and its analogs, a distinct flavor in whiskey, foods, and beverages, display different inclusion complexes with α‐Cyclodextrin (α‐CD) and can be detected on a Nafion modified boron‐doped diamond (BDD) electrode. The stable Nafion layer preconcentrates the analyte‐α‐CD complexes prior to electroanalysis by square wave voltammetry (SWV) to enhance detection sensitivities. This sensing mode together with peak deconvolution successfully distinguishes between guaiacol, 4‐ethylguaiacol (4‐EG), three cresol isomers, and phenols in a popular whiskey brand. The results obtained are corroborated by high‐performance liquid chromatography (HPLC). Anodic oxidation at + 2 V in phosphate buffer, pH 7 is proven as an effective method to renew the electrode surface after its exposure to the guaiacols. This robust approach circumvents several drawbacks associated with the use of enzymes and nanomaterials for the analysis of such analytes as reported in the literature.
An Electrochemical Biosensor Platform for Testing of Dehydroepiandrosterone 3‐Sulfate (DHEA−S) as a Model for Doping Materials
Authors: Balaban Simge , Durmus Ceren , Celikbas Eda , Gumus Zinar Pinar , Timur Suna
Published: August 2019

Endogenous steroids such as dehydroepiandrosterone (DHEA) and dehydroepiandrosterone 3‐sulfate (DHEA−S) have commonly used as doping materials by athletes and to date novel techniques are needed for detection of these molecules. In this study, antibody‐based electrochemical biosensor has developed for testing level of the DHEA−S. For this aim, gold surfaces were initially modified with cysteamine (Cys) and then, DHEA−S antibody was immobilized on the surface via glutaraldehyde (GA) as a crosslinking agent. The stepwise modification of electrode surface was monitored by using various electrochemical techniques such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Linear range was determined as 2.5–100 ng/mL DHEA−S using differential pulse voltammetry (DPV) technique, as well. Moreover, repeatability (±S.D.), coefficient of variation (%) and limit of detection (LOD) values were calculated as 0.033, 1.030 and 3.971, respectively. Also, DHEA−S in synthetic serum and urine samples were successfully determined with standard addition method and confirmation analysis were performed with liquid chromatography quadrupole‐time of flight mass spectrometry (LC‐QTOF/MS) system. The selectivity was studied with the addition of some interfering molecules (testosterone, bovine serum albumin (BSA), cholesterol, uric acid, lactic acid, codein (COD), ascorbic acid, DHEA). Consequently, this work is proposed as practical, innovative and cost‐effective technique that can be easily adapted for the miniaturized form for the analysis of other doping substances as well as DHEA−S for the future works.
Evaporation of Electrolyte during SVET Measurements: The Scale of the Problem and the Solutions
Authors: Bouali A. C. , Bastos A. C. , Lamaka S. V. , Serdechnova M. , Ferreira M. G. S. , Zheludkevich M. L.
Published: August 2019

The objective of this work is to investigate the scale of the effect of spontaneous solution evaporation during SVET (Scanning Vibrating Electrode Technique) measurements and demonstrate how it biases the final results. When SVET maps are continuously acquired for more than several hours, the measured currents are smaller than expected. This is attributed to solvent (typically water) evaporation which leads to an increase in solution conductivity over time. If this is not considered when converting the measured potential differences into the local current densities, the SVET results display currents smaller than the true ones. Here, this effect is studied with a platinum disk electrode as source of a constant current and a model corroding system consisting of the AA2024/CFRP galvanic couple. Corrective actions are proposed to mitigate the problem, either in the experimental set‐up or as numerical correction.
Perspectives of surface plasmon resonance sensors for optimized biogas methanation
Authors: Lamb Jacob J. , Bernard Olivier , Sarker Shiplu , Lien Kristian M. , Hjelme Dag Roar
Published: August 2019

Biogas production is becoming significantly viable as an energy source for replacing fossil‐based fuels. The further development of the biogas production process could lead to significant improvements in its potential. Wastewater treatment currently accounts for 3% of the electrical energy load in developed countries, while it could be developed to provide a source of nitrogen and phosphorus, in addition to energy. The improvement of anaerobic digestion (AD) detection technologies is the cornerstone to reach higher methane productivities and develop fully automatized processes to decrease operational costs. New sensors are requested to automatically obtain a better interpretation of the complex and dynamical internal reactor environment. This will require detailed systematic detection in order to realize a near‐optimal production process. In this review, optical fiber‐based sensors will be discussed to assess their potential for use in AD. There is currently a disparity between the complexity of AD, and online detection. By improving the durability, sensitivity, and cost of dissolved H2 (as well as H2S, acetic acid, ammonia, and methane) sensor technology, further understanding of the AD process may allow the prevention of process failure. The emergence of surface plasmon resonance (SPR) sensing with optical fibers coupled with the H2‐sensitive metal palladium, allows detection of dissolved hydrogen in liquid. By implementing these SPR sensors into AD, improvements to the biogas production process, even at small scales, may be achieved by guiding the process in the optimum direction, avoiding the collapse of the biological process. This review intends to assess the feasibility of online, cost‐effective, rapid, and efficient detection of dissolved H2, as well as briefly assessing H2S, acetic acid, ammonia, and methane in AD by SPR.
MAOA‐VNTR genotype affects structural and functional connectivity in distributed brain networks
Authors: Harneit Anais , Braun Urs , Geiger Lena S. , Zang Zhenxiang , Hakobjan Marina , van Donkelaar Marjolein M. J. , Schweiger Janina I. , Schwarz Kristina , Gan Gabriela , Erk Susanne , Heinz Andreas , Romanczuk‐Seiferth Nina , Witt Stephanie , Rietschel Marcella , Walter Henrik , Franke Barbara , Meyer‐Lindenberg Andreas , Tost Heike
Published: August 2019

Previous studies have linked the low expression variant of a variable number of tandem repeat polymorphism in the monoamine oxidase A gene (MAOA‐L) to the risk for impulsivity and aggression, brain developmental abnormalities, altered cortico‐limbic circuit function, and an exaggerated neural serotonergic tone. However, the neurobiological effects of this variant on human brain network architecture are incompletely understood. We studied healthy individuals and used multimodal neuroimaging (sample size range: 219–284 across modalities) and network‐based statistics (NBS) to probe the specificity of MAOA‐L‐related connectomic alterations to cortical‐limbic circuits and the emotion processing domain. We assessed the spatial distribution of affected links across several neuroimaging tasks and data modalities to identify potential alterations in network architecture. Our results revealed a distributed network of node links with a significantly increased connectivity in MAOA‐L carriers compared to the carriers of the high expression (H) variant. The hyperconnectivity phenotype primarily consisted of between‐lobe (“anisocoupled”) network links and showed a pronounced involvement of frontal‐temporal connections. Hyperconnectivity was observed across functional magnetic resonance imaging (fMRI) of implicit emotion processing (pFWE = .037), resting‐state fMRI (pFWE = .022), and diffusion tensor imaging (pFWE = .044) data, while no effects were seen in fMRI data of another cognitive domain, that is, spatial working memory (pFWE = .540). These observations are in line with prior research on the MAOA‐L variant and complement these existing data by novel insights into the specificity and spatial distribution of the neurogenetic effects. Our work highlights the value of multimodal network connectomic approaches for imaging genetics.
Employee share ownership, training, and early promotion policy as a bundle in enhancing labor productivity: A test of the three‐way interaction effect
Authors: Yoon Yeongjoon , Sengupta Sukanya
Published: August 2019

The three‐way interaction effect of (broad‐based) employee share ownership (ESO), training, and early promotion policy on labor productivity was examined in a longitudinal sample of 614 organizations (1,605 organization‐year data points) in Korea. The ESO–productivity relationship was positive only when the investment in training was high and the opportunity for early promotion was present. However, we found no evidence for the two‐way interaction effects of ESO and training and ESO and early promotion policy on labor productivity. The results are in alignment with the emergent view that the productivity benefits of ESO can be better realized when ESO coexists with a bundle of complementary human resource management (HRM) practices. Thus, this study meaningfully extends the contingency perspective and related studies in the ESO literature, which tend to examine the productivity effect of ESO in isolation or in conjunction with a single HRM practice.
Transfer of treatment effects from combined to isolated conditions during functional communication training for multiply controlled problem behavior
Authors: Tsami Loukia , Lerman Dorothea C.
Published: August 2019

Functional communication training (FCT) is highly effective for treating socially maintained problem behavior when based on the results of functional analyses (FA). Research suggests that combining relevant antecedents and consequences of problem behavior during FCT can be an efficient approach to treatment for behavior that is multiply controlled. However, no studies have evaluated whether treatment effects under combined conditions would transfer to single, or isolated, conditions. Participants were 5 children with autism, aged 3 years to 6 years, who engaged in problem behavior maintained by both escape from demands and access to tangibles. An experimenter coached their caregivers via video conferencing to implement FA and FCT in their homes. All participants received FCT under a combined condition, followed by brief exposure to sessions with isolated antecedents and consequences. Treatment effects for just 1 of the 5 participants immediately persisted under isolated conditions. These results suggest that, when caregivers combine variables relevant to multiple functions during FCT, exposure to isolated conditions may at least temporarily produce treatment failures.
Concentration‐dependent cellular behavior and osteogenic differentiation effect induced in bone marrow mesenchymal stem cells treated with magnetic graphene oxide
Authors: He Yi , Li Yiming , Chen Guanhui , Wei Changbo , Zhang Xiliu , Zeng Binghui , Yi Chen , Wang Chao , Yu Dongsheng
Published: August 2019

The scaffold‐free cell sheet plays an important role in stem‐cell‐based regeneration. Graphene oxide (GO) endows nanoparticles (NPs) with special characteristics and therefore has attracted increasing attention in recent years. However, the existence of toxicity in GO and its derivatives limits their ability to promote osteogenic differentiation. Magnetic graphene oxide (MGO), a novel combination of Fe3O4 and GO with diverse unique properties, has not been studied in bone tissue engineering. In this study, MGO was fabricated, and the previously undiscovered relationships—including cellular behavior and the effects of osteogenic differentiation and related mechanisms of MGO in rat bone‐marrow‐derived mesenchymal stem cells (BMSCs)—were investigated for the first time. Here, we found that MGO was not only biocompatible at low concentrations, but also could significantly accelerate osteogenic differentiation in BMSCs. Both the cellular behavior and bone‐formation differentiation in BMSCs treated with MGO showed concentration‐dependent characteristics. In addition, the regulation of osteogenic differentiation in BMSCs treated with MGO might be involved with the Wnt/β‐catenin and BMP signaling pathways. Furthermore, MGO demonstrated a better ability for osteogenic differentiation in BMSCs than did GO. The current work indicated a significant use for MGO nanocomposite scaffolds in biocompatibility and bone regeneration, which could provide new insight into bone regeneration in the future.
Photocatalytic disinfection and purification of water employing reduced graphene oxide/TiO2 composites
Authors: Berberidou Chrysanthi , Kyzas George Z , Paspaltsis Ioannis , Sklaviadis Theodoros , Poulios Ioannis
Published: August 2019

BACKGROUND

Recombination of photogenerated carriers in titanium dioxide (TiO2)‐mediated semiconducting photocatalysis is considered to be the principal obstacle in its unlimited exploitation in practical applications. Hybridization of TiO2 with graphene‐based materials appears to be a highly promising alternative. In this context, reduced graphene oxide (rGO)/TiO2 composites were prepared using a simple ultrasonically assisted route under mild reaction conditions.

RESULTS

The as‐prepared composites were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy‐dispersive X‐ray spectrometry (EDS), Fourier‐transform infrared spectroscopy (FTIR) and nitrogen adsorption–desorption isotherms. Photocatalytic efficiencies of the as‐prepared composites were evaluated employing the pesticide clopyralid as a model pollutant. Initial degradation and mineralization rates obtained in the presence of the as‐prepared composites were, in all cases, higher than the one obtained in the presence of the bare TiO2, with 5% rGO/TiO2 achieving the highest r0 and rDOC values. The as‐prepared composites also were evaluated based on their potential to inactivate bacterial endospores of the Bacillus stearothermophilus species, well‐known for their extraordinary resistance to most inactivation processes. Prevalence of 5% rGO/TiO2 in the inactivation of B. stearothermophilus among all as‐prepared materials was evident, accomplished within 120 min of UV‐A illumination. Real‐time PCR experiments enabled the detection of genomic DNA released during photocatalytic oxidation, in the presence of 5% rGO/TiO2 and UV‐A, suggesting lysis of the outer and inner spore coat caused by the generated ROS.

CONCLUSIONS

These findings demonstrate the potential of rGO, a low‐cost, nontoxic material to serve as a reliable alternative in the enhancement of TiO2 photocatalytic efficiency in water processing applications. © 2019 Society of Chemical Industry
Analysis of color shift on butterfly wings by Fourier transform of images from atomic force microscopy
Authors: Kaspar Pavel , Sobola Dinara , Sedlák Petr , Holcman Vladimír , Grmela Lubomír
Published: August 2019

Butterfly wings have complex structure lending it several interesting properties. Coloration of the wing is one of the first things to encounter and the overall visual effect is in fact influenced by several factors. Chemical pigments set the base color of the wing, topographical structures on the wing scales cause color shift by interference and their arrangement into diffraction grating causes iridescence. The thin film interference can be attributed to microscopic ridges covering wing scales. Observation and calculation of the color shift on wings of Euploea mulciber species using Fourier transform of images obtained by atomic force microscopy is the focus of this article.
Synthesis and Pharmacological Evaluation of 4‐Aryloxyquinazoline Derivatives as Potential Cytotoxic Agents
Authors: Malhotra Anjleena , Kaur Tejinder , Bansal Ranju
Published: August 2019

In the present study, novel 4‐aryloxyquinazoline derivatives were synthesized and screened for in vitro cytotoxicity on human cancer cell lines at 10 μM. Some of the synthesized compounds displayed moderate to significant and selective cytotoxic activity against various leukemia, melanoma, ovarian, breast, and colon cancer cell lines. (E)‐3‐(3,4‐Dimethoxyphenyl)‐1‐(4‐(quinazolin‐4‐yloxy)phenyl)prop‐2‐en‐1‐one (9b) was the most potent compound among all with an average growth inhibition of 70% against leukemia cancer cell lines. The compound also produced strong inhibition (75%) of colon cancer cell lines with 42.58% lethality of HCT‐116 cell line.
HIV‐1 DNA decay is faster in children who initiate ART shortly after birth than later
Authors: Veldsman Kirsten A , Janse van Rensburg Anita , Isaacs Shahieda , Naidoo Shalena , Laughton Barbara , Lombard Carl , Cotton Mark F , Mellors John W , van Zyl Gert U
Published: August 2019

Introduction

There is limited data in children on whether persistence of HIV‐1 infected cells is affected by age at initiating antiretroviral therapy (ART), its duration or any subsequent ART interruption. We therefore investigated the effects of both age of ART initiation and duration of ART interruption on HIV‐1 DNA decay in children.

Methods

We investigated HIV‐1 DNA decay in three groups of children on ART: Group‐1 (n = 7) started uninterrupted ART within eight days of life; Group‐2 (n = 8) started uninterrupted ART at a median of five months of age; and Group‐3 (n = 23) started ART at a median age of 1.8 months for either 40 or 96 weeks, then interrupted ART (median of seven months), and restarted ART based on CD4 count and clinical criteria. Total HIV‐1 DNA was assayed using a sensitive HIV‐1 subtype C‐adapted quantitative PCR for integrase. The duration of ART was square root transformed to fit the observed slowing of HIV‐1 DNA decay rate. For each group, point estimates for decay rates were determined after six months of continuous suppressive ART in groups 1 and 2 or six months after restarting ART in Group‐3. Groups‐2 and 3 were combined using a mixed effect regression model to investigate covariates of HIV‐1 DNA decay rate.

Results and Discussion

At six months of continuous suppressive ART, the HIV‐1 DNA t½ (95% CI) was shorter in Group‐1 (n = 7): 2.7 months (2.1 to 3.8), than 9.2 months (7.4 to 12.1) in Group‐2 (n = 8); and 9.6 months (7.6 to 12.6) in Group‐3 (n = 23) (p < 0.01). In multivariable analyses, HIV‐1 DNA before treatment (p < 0.001) and the change in HIV‐1 DNA during interruption (p < 0.01) were independent predictors of slower HIV‐1 DNA decay.

Conclusions

These data suggest that ART initiation within the first week of life can reduce the persistence of long‐lived infected cells. Delaying ART is associated with slower decay of infected cells.
Spectral Signatures in the Different Layers of the Human Eyelid by Photoacoustic Imaging
Authors: Dahlstrand Ulf , Sheikh Rafi , Berggren Johanna , Hult Jenny , Albinsson John , Cinthio Magnus , Malmsjö Malin
Published: August 2019

Background and Objectives

The eyelids are susceptible to a number of skin cancers, which are challenging to excise radically without sacrificing excessive healthy tissue. Photoacoustic (PA) imaging is an emerging non‐invasive biomedical imaging modality that could potentially be used for intraoperative micrographic control of the surgical margins of eyelid tumors. In this study, non‐cancerous human eyelid tissue was characterized using PA as a first step in the development of this technique.

Study Design/Materials and Methods

Twelve full‐thickness samples from nine patients were analyzed ex vivo using PA imaging. Two‐dimensional PA images were acquired using 59 wavelengths in the range of 680–970 nm to obtain the spectral signatures of the skin, orbicularis oculi muscle, and the tarsal plate. Three‐dimensional images were obtained by scanning the tissues using a linear stepping motor. Spectral unmixing was performed to visualize the chromophore distribution.

Results

The resulting PA spectra could be used to differentiate between the orbicularis oculi muscle and the other two structures (P < 0.05). The signals from the skin and the tarsal plate were more similar in appearance, probably due to similarities in their molecular composition. Spectral unmixing provided a clear visualization of the overall architecture of the eyelids.

Conclusions

PA imaging can be used to differentiate between the orbicularis oculi muscle and the eyelid skin and tarsal plate. The main structures of human eyelids could be visualized in three dimensions using PA imaging. This technique could potentially be used to examine eyelid tumors intraoperatively in the future. However, further studies on tumors in vivo are needed before considering such clinical use. Lasers Surg Med. © 2019 Wiley Periodicals, Inc.
Reconstruction of radiation‐induced ulcers with free flaps using the perforating vessel as a recipient vessel
Authors: Kim Ji Min , Kim Seong Ae , Kwon Hyo Jeong , Moon Suk‐Ho , Oh Deuk Young , Rhie Jong Won , Jun Young‐Joon
Published: August 2019

Background

Free flaps can be options for coverage of radiation ulcers. However, due to radiation damage, it may be hard to find and dissect a reliable recipient vessel for microsurgical anastomosis. When the radiation fields are targeted for deep tissues, superficial tissues may be less affected by radiation. Therefore, damage to perforator vessels near the skin may be lesser than that to the major vessels in deeper structures. We would like to introduce our experiences of using these less injured perforating vessels within or near the wound as recipient vessels for free flap coverage.

Patients and Methods

From 2013 to 2015, 11 patients underwent free flap coverage for the treatment of radiation‐induced ulceration. The location of ulcers were three cases of thigh, two cases of inguinal area, axilla, trochanteric area, chest wall, lower leg, perineal area, and back. Eleven cases were reconstructed using the anterolateral thigh (ALT) perforator flap, and in one case, the thoracodorsal artery perforator (TDAP) flap was used for inguinal area defect. With preoperative computed tomography, we found perforating vessels around the radiation ulcer. The perforating vessels that were identified before the operation were detected by hand‐held Doppler during the operation and meticulous dissection was performed. In all‐cases, the perforating vessels were accompanied by vena commitantes. A reliable perforator is one with visible pulsation, strong sound detected on Doppler, and sufficient diameter, preferably larger than 0.6 mm. Anastomosis was performed after confirming that the blood vessel was reliable.

Results

The flap sizes ranged from 7 × 6 cm to 24 × 10 cm. No flap total necrosis developed. Patients were followed in the outpatient clinic for 21 to 31 months postoperatively. No patients experienced recurrence of ulceration during the follow‐up.

Conclusions

In free flap reconstruction of radiation ulcers, using perforating vessels within or outside the ulcer as recipient vessels provided less damaged vessels and healthier flaps for the defects with minimal wound complications. These perforating vessels can be a good option as recipient vessel for free flap coverage of radiation ulcers.
High correlation between radiation dose estimates for 256‐slice CT obtained by highly parallelized hybrid Monte Carlo computation and solid‐state metal‐oxide semiconductor field‐effect transistor measurements in physical anthropomorphic phantoms
Authors: Prinsen Peter , Trattner Sigal , Wiegert Jens , Gerland Elazar‐Lars , Shefer Efrat , Morton Thomas , Thompson Carla M. , Cheng Bin , Halliburton Sandra S. , Einstein Andrew J.
Published: August 2019

Purpose

Accurate, patient‐specific radiation dosimetry for CT scanning is critical to optimize radiation doses and balance dose against image quality. While Monte Carlo (MC) simulation is often used to estimate doses from CT, comparison of estimates to experimentally measured values is lacking for advanced CT scanners incorporating novel design features. We aimed to compare radiation dose estimates from MC simulation to doses measured in physical anthropomorphic phantoms using metal‐oxide semiconductor field‐effect transistors (MOSFETs) in a 256‐slice CT scanner.

Methods

Fifty MOSFETs were placed in organs within tissue‐equivalent anthropomorphic adult and pediatric radiographic phantoms, which were scanned using a variety of chest, cardiac, abdomen, brain, and whole‐body protocols on a 256‐slice system. MC computations were performed on voxelized CT reconstructions of the phantoms using a highly parallel MC tool developed specifically for diagnostic X‐ray energies and rapid computation. Doses were compared between MC estimates and physical measurements.

Results

The average ratio of MOSFET to MC dose in the in‐field region was close to 1 (range, 0.96–1.12; mean ± SD, 1.01 ± 0.04), indicating outstanding agreement between measured and simulated doses. The difference between measured and simulated doses tended to increase with distance from the in‐field region. The error in the MC simulations due to the limited number of simulated photons was less than 1%. The errors in the MOSFET dose determinations in the in‐field region for a single scan were mainly due to the calibration method and were typically about 6% (8% if the error in the reading of the ionization chamber that was used for the MOSFET calibration was included).

Conclusions

Radiation dose estimation using a highly parallelized MC method is strongly correlated with experimental measurements in physical adult and infant anthropomorphic phantoms for a wide range of scans performed on a 256‐slice CT scanner. Incorporation into CT scanners of radiation‐dose distribution estimation, employing the scanner’s reconstructed images of the patient, may offer the potential for accurate patient‐specific CT dosimetry.
Purity determination of a new antifungal drug candidate using quantitative 1H NMR spectroscopy: Method validation and comparison of calibration approaches
Authors: Franco Pedro Henrique Cavalcanti , Braga Saulo Fehelberg Pinto , de Oliveira Renata Barbosa , César Isabela Costa
Published: August 2019

Quantitative nuclear magnetic resonance (qNMR) is an analytical technique that offers numerous advantages in pharmaceutical applications including minimum sample preparation and rapid data collection times with no need for response factor corrections, being a powerful tool for assaying drug content in both drug discovery and early drug development. In the present work, we have applied qNMR, using both the internal standard and the electronic reference to access in vivo concentrations 2 calibration methods, to assess the purity of RI76, a novel antifungal drug candidate. NMR acquisition and processing parameters were optimized in order to obtain spectra with intense, well‐resolved signals of completely relaxed nuclei. The analytical method was validated following current guidelines, demonstrating selectivity, linearity, accuracy, precision, and robustness. The calibration approaches were statistically compared, and no significant difference was observed when comparing the obtained results and their dispersion in terms of relative standard deviation. The proposed qNMR method may, therefore, be used for both qualitative and quantitative assessments of RI76 in early drug development and for characterization of this compound.
Time optimal control‐based RF pulse design under gradient imperfections
Authors: Aigner Christoph S. , Rund Armin , Abo Seada Samy , Price Anthony N. , Hajnal Joseph V. , Malik Shaihan J. , Kunisch Karl , Stollberger Rudolf
Published: August 2019

Purpose

This study incorporates a gradient system imperfection model into an optimal control framework for radio frequency (RF) pulse design.

Theory and Methods

The joint design of minimum‐time RF and slice selective gradient shapes is posed as an optimal control problem. Hardware limitations such as maximal amplitudes for RF and slice selective gradient or its slew rate are included as hard constraints to assure practical applicability of the optimized waveforms. In order to guarantee the performance of the optimized waveform with possible gradient system disturbances such as limited system bandwidth and eddy currents, a measured gradient impulse response function (GIRF) for a specific system is integrated into the optimization.

Results

The method generates optimized RF and pre‐distorted slice selective gradient shapes for refocusing that are able to fully compensate the modeled imperfections of the gradient system under investigation. The results nearly regenerate the optimal results of an idealized gradient system. The numerical Bloch simulations are validated by phantom and in‐vivo experiments on 2 3T scanners.

Conclusions

The presented design approach demonstrates the successful correction of gradient system imperfections within an optimal control framework for RF pulse design.
Benign acute viral myositis in African migrants: A clinical, serological, and pathological study
Authors: Pancheri Elia , Lanzafame Massimiliano , Zamò Alberto , Angheben Andrea , Sartoris Silvia , Zorzi Antonella , Boaretti Marzia , Signoretto Caterina , Guglielmi Valeria , Ferrari Sergio , Tonin Paola , Vattemi Gaetano
Published: August 2019

Background

Several viruses have been described as causes of acquired inflammatory myopathies; however, the mechanisms by which they cause muscle disease are still unclear. The aim of this study was to describe the laboratory features of benign acute myositis in a small case series.

Methods

A detailed pathological and serological analysis was performed in five African migrants who developed an acute viral myositis complicated by rhabdomyolysis.

Results

Muscle biopsies clearly documented an inflammatory myopathy with histological features similar to polymyositis including CD8+ T cells surrounding and invading nonnecrotic muscle fibers, CD68+ macrophages and major histocompatibility complex class I antigen upregulation. In addition, positivity for myositis‐specific antibodies (MSA), in particular anti‐aminoacyl tRNA synthetases, was found in the serum of two patients.

Conclusions

Our study demonstrated that T‐cell mediated injury occurs in muscle of patients with acute viral myositis, and that MSA may be present in the serum of these patients.