bluuebunny/crossref_metadata_2025 huggingface dataset:
Palladium Nanoparticles Bonded to Two‐Dimensional Iron Oxide Graphene Nanosheets: A Synergistic and Highly Reusable Catalyst for the Tsuji–Trost Reaction in Water and Air
Authors: Liu Jian , Huo Xing , Li Tianrong , Yang Zhengyin , Xi Pinxian , Wang Zhiyi , Wang Baodui
Published: July 2014

Low cost, high activity and selectivity, convenient separation, and increased reusability are the main requirements for noble‐metal‐nanocatalyst‐catalyzed reactions. Despite tremendous efforts, developing noble‐metal nanocatalysts to meet the above requirements remains a significant challenge. Here we present a general strategy for the preparation of strongly coupled Fe3O4 and palladium nanoparticles (PdNPs) to graphene sheets by employing polyethyleneimine as the coupling linker. Transmission electron microscopic images show that Pd and Fe3O4 nanoparticles are highly dispersed on the graphene surface, and the mean particle size of Pd is around 3 nm. This nanocatalyst exhibits synergistic catalysis by Pd nanoparticles supported on reduced graphene oxide (rGO) and a tertiary amine of polyethyleneimine (Pd/Fe3O4/PEI/rGO) for the Tsuji–Trost reaction in water and air. For example, the reaction of ethyl acetoacetate with allyl ethyl carbonate afforded the allylated product in more than 99 % isolated yield, and the turnover frequency reached 2200 h−1. The yield of allylated products was 66 % for Pd/rGO without polyethyleneimine. The catalyst could be readily recycled by a magnet and reused more than 30 times without appreciable loss of activity. In addition, only about 7.5 % of Pd species leached off after 20 cycles, thus rendering this catalyst safer for the environment.
Total Synthesis of Isoquinocyclinone
Authors: Dischmann Mike , Frassetto Timo , Breuning M. André , Koert Ulrich
Published: July 2014

The total synthesis of the heptacyclic natural product isoquinocyclinone has been achieved. A Hauser annulation was used to assemble the anthraquinone core structure. The unique 2,4,5,6‐tetrahydropyrrolo[2,3‐b]pyrrole substructure was prepared by alkyne addition to a lactone intermediate and subsequent Ni0‐mediated cyanide addition, the conversion of an O,O‐ into an N,O‐acetal, and final intramolecular N‐alkylation.
From Double‐Four‐Ring Germanosilicates to New Zeolites: In Silico Investigation
Authors: Trachta Michal , Bludský Ota , Čejka Jiří , Morris Russell E. , Nachtigall Petr
Published: July 2014

To date, the majority of zeolites have been prepared by the solvothermal route using organic structure directing agents. Two new zeolites with structural codes PCR and OKO were recently prepared from UTL germanosilicate by removal of the double‐four ring (D4R) connecting the dense two‐dimensional layers [Nature Chem. 2013, 5, 628]. The corresponding experimental protocol, Assembly–Disassembly–Organization–Reassembly (ADOR), is explored in this contribution with an in silico investigation. The structure and properties of hypothetical zeolites that could be obtained from zeolites with IWW, IWV, IWR, ITR, and ITH topologies using the ADOR protocol are reported based on a computational investigation. A total of 20 new structures are presented together with their characteristics.
High‐Performance Polymers from Nature: Catalytic Routes and Processes for Industry
Authors: Walther Guido
Published: July 2014

It is difficult to imagine life today without polymers. However, most chemicals are almost exclusively synthesized from petroleum. With diminishing oil reserves, establishing an industrial process to transform renewables into high‐value chemicals may be more challenging than running a car without gasoline. This is due to the difficulty in setting up processes that are novel, profitable, and environmentally benign at the same time. Additionally, the quest for sustainability of renewable resources should be based on incorporating ethical considerations in the development of plans that utilize feedstocks intended for human nutrition and health. Thus, it is important to use bio‐energy containing renewable resources in the most efficient way. This Concept goes beyond the synthesis of monomers and provides insights for establishing an industrial process that transforms renewable resources into high‐value chemicals, and it describes careful investigations that are of paramount importance, including evaluations from an economical and an ecological perspective. The synthesis of monomers suitable for polymer production from renewable resources would ideally be accompanied by a reduction in CO2 emission and waste, through the complete molecular utilization of the feedstock. This Concept advocates the drop‐in strategy, and is guided by the example of catalytically synthesized dimethyl 1,19‐nonadecanedioate and its α,ω‐functionalized derivatives. With respect to the Twelve Principles of Green Chemistry, this Concept describes a technological leap forward for a sustainable green chemical industry.
Investigation of the Effect of the Substrate Position Relative to the Source on the Optoelectrical and Structural Properties of Pure Nanostructured Tin Oxide by APCVD
Authors: Maleki Masoudeh , Rozati Seyed Mohammad
Published: July 2014

Pure tin oxide (TO) films are deposited onto glass substrates at various substrate angles relative to the source position by a simple and inexpensive method of atmospheric pressure (AP)CVD. The deposition temperature is constant at about 500°C, and oxygen with a flow rate of 100 sccm is used as both the carrier gas and the oxidizing agent. Investigation of the sheet resistance shows that resistivity varies between 106 and. 241 Ω/□. X‐ray diffraction (XRD) also reveals that the structure is polycrystalline with the preferred orientation of (110) for all films deposited at the various substrate angles. Scanning electron microscopy (SEM) images also reveal a uniform and impacted structure on the surface of all the films. Optical properties show clear changes as a result of the substrate position versus the source.
Security and performance enhancement of AODV routing protocol
Authors: Simaremare Harris , Abouaissa Abdelhafid , Sari Riri Fitri , Lorenz Pascal
Published: July 2014

A mobile ad hoc networks (MANET) is a decentralized, self‐organizing, infrastructure‐less network and adaptive gathering of independent mobile nodes. Because of the unique characteristics of MANET, the major issues to develop a routing protocol in MANET are the security aspect and the network performance. In this paper, we propose a new secure protocol called Trust Ad Hoc On‐demand Distance Vector (AODV) using trust mechanism. Communication packets are only sent to the trusted neighbor nodes. Trust calculation is based on the behaviors and activities information of each node. It is divided in to trust global (TG) and trust local (TL). TG is a trust calculation based on the total of received routing packets and the total of sending routing packets. TL is a comparison between total received packets and total forwarded packets by neighbor node from specific nodes. Nodes conclude the total trust level of its neighbors by accumulating the TL and TG values. The performance of Trust AODV is evaluated under denial of service/distributed denial of service (DOS/DDOS) attack using network simulator NS‐2. It is compared with the Trust Cross Layer Secure (TCLS) protocol. Simulation results show that the Trust AODV has a better performance than TCLS protocol in terms of end‐to‐end delay, packet delivery ratio, and overhead. Next, we improve the performance of Trust AODV using ant algorithm. The proposed protocol is called Trust AODV + Ant. The implementation of ant algorithm in the proposed secure protocol is by adding an ant agent to put the positive pheromone in the node if the node is trusted. Ant agent is represented as a routing packet. The pheromone value is saved in the routing table of the node. We modified the original routing table by adding the pheromone value field. The path communication is selected based on the pheromone concentration and the shortest path. Trust AODV + Ant is compared with simple ant routing algorithm (SARA), AODV, and Trust AODV under DOS/DDOS attacks in terms of performance. Simulation results show that the packet delivery ratio and throughput of the Trust AODV increase after using ant algorithm. However, in terms of end‐to‐end delay, there is no significant improvement. Copyright © 2014 John Wiley & Sons, Ltd.
NMDA receptors on zebrafish Mauthner cells require CaMKII‐α for normal development
Authors: Roy Birbickram , Ferdous Jannatul , Ali Declan W.
Published: July 2014

Calcium/calmodulin dependent protein kinase 2 (CaMKII) is a multifunctional protein that is highly enriched in the synapse. It plays important roles in neuronal functions such as synaptic plasticity, synaptogenesis, and neural development. Gene duplication in zebrafish has resulted in the occurrence of seven CaMKII genes (camk2a, camk2b1, camk2b2, camk2g1, camk2g2, camk2d1, and camk2d2) that are developmentally expressed. In this study, we used single cell, real‐time quantitative PCR to investigate the expression of CaMKII genes in individual Mauthner cells (M‐cells) of 2 days post fertilization (dpf) zebrafish embryos. We found that out of seven different CaMKII genes, only the mRNA for CaMKII‐α was expressed in the M‐cell at detectable levels, while all other isoforms were undetectable. Morpholino knockdown of CaMKII‐α had no significant effect on AMPA synaptic currents (mEPSCs) but decreased the amplitude of NMDA mEPSCs. NMDA events exhibited a biexponential decay with τfast ≈ 30 ms and τslow ≈ 300 ms. Knockdown of CaMKII‐α specifically reduced the amplitude of the slow component of the NMDA‐mediated currents (mEPSCs), without affecting the fast component, the frequency, or the kinetics of the mEPSCs. Immunolabelling of the M‐cell showed increased dendritic arborizations in the morphants compared with controls, and knockdown of CaMKII‐α altered locomotor behaviors of touch responses. These results suggest that CaMKII‐α is present in embryonic M‐cells and that it plays a role in the normal development of excitatory synapses. Our findings pave the way for determining the function of specific CaMKII isoforms during the early stages of M‐cell development. © 2014 Wiley Periodicals, Inc. Develop Neurobiol 75: 145–162, 2015
A national survey of eating disorder training
Authors: Mahr Fauzia , Farahmand Pantea , Bixler Edward O. , Domen Ronald E , Moser Eileen M. , Nadeem Tania , Levine Rachel L. , Halmi Katherine A.
Published: July 2014

Objective

Eating disorders (EDs) result in the highest mortality rate of all psychiatric disorders, and in the United States, approximately one in twenty females suffers from an eating disorder. However, training provided within residency programs to address the needs of these patients is sparse. The objective of this study was to conduct a national survey that assesses the amount of EDs training for trainees across five ACGME accredited specialties: internal medicine, pediatrics, family medicine, psychiatry, and child and adolescent psychiatry. The results of the survey will be used to develop strategies to improve eating disorder education among residents.

Method

Eight hundred eighty training coordinators were contacted using information available on the ACGME website and asked to complete the survey.

Results

Of the 637 responding programs, 514 did not offer any scheduled or elective rotations for EDs. Of the 123 programs offering rotations, only 42 offered a formal, scheduled rotation. Child and adolescent psychiatry offered the most clinical experiences, and pediatric programs offered the greatest number of didactic hours on EDs.

Discussion

Training in EDs is limited. Simulated patient encounters, massive open online courses, web‐based curricula, dedicated rotations and clinical experiences, didactic curricula, and brief‐training programs may help to improve eating disorder diagnostic and treatment skills among trainees. © 2014 Wiley Periodicals, Inc. (Int J Eat Disord 2015; 48:443–445)
A symmetry preserving dissipative artificial viscosity in r‐z geometry
Authors: Váchal Pavel , Wendroff Burton
Published: July 2014

We present a novel artificial viscosity for staggered Lagrangian schemes in 2D axi‐symmetric r‐z geometry on logically rectangular grids. The suggested viscous force is dissipative by construction, conserves both components of momentum, and preserves spherical symmetry on an equiangular polar grid. This method turns out to be robust and performs well for spherically symmetric problems on various grid types (symmetric, perturbed polar, rectangular), without any need for tinkering with problem‐dependent or grid‐dependent parameters. The results are compared with the outcome of the area‐weighted approach using the popular tensor viscosity by Campbell and Shashkov. Copyright © 2014 John Wiley & Sons, Ltd.
NERC's Reliability Assurance Initiative: What Registered Entities Can Do
Authors: Wiseman J. Porter , Sullivan Julia E.
Published: July 2014

In the summer of 2003, a handful of power lines in Ohio tripped after making contact with overgrown trees. Over the next 13 minutes, the electric grid experienced cascading failures that left an estimated 50 million people in the United States and Canada without power. Two years later, Congress added Section 215 to the Federal Power Act, giving the Federal Energy Regulatory Commission (FERC) jurisdiction over the reliability of the bulk power system (BPS). Section 215 also directed FERC to designate an Electric Reliability Organization (ERO) to establish and enforce reliability standards with penalties up to a million dollars per day per violation.
Shape‐based virtual screening with volumetric aligned molecular shapes
Authors: Koes David Ryan , Camacho Carlos J.
Published: July 2014

Shape‐based virtual screening is an established and effective method for identifying small molecules that are similar in shape and function to a reference ligand. We describe a new method of shape‐based virtual screening, volumetric aligned molecular shapes (VAMS). VAMS uses efficient data structures to encode and search molecular shapes. We demonstrate that VAMS is an effective method for shape‐based virtual screening and that it can be successfully used as a prefilter to accelerate more computationally demanding search algorithms. Unique to VAMS is a novel minimum/maximum shape constraint query for precisely specifying the desired molecular shape. Shape constraint searches in VAMS are particularly efficient and millions of shapes can be searched in a fraction of a second. We compare the performance of VAMS with two other shape‐based virtual screening algorithms a benchmark of 102 protein targets consisting of more than 32 million molecular shapes and find that VAMS provides a competitive trade‐off between run‐time performance and virtual screening performance. © 2014 Wiley Periodicals, Inc.
Educating Coaches to Power Dynamics: Managing Multiple Agendas Within the Triangular Relationship
Authors: Louis Dima , Fatien Diochon Pauline
Published: July 2014

Through a study of 20 semistructured interviews using the critical incident method, this article explores the nature of the multiple agendas within the triangular relationship that connects the coach, coachee, and an organization and the challenges associated with their management. The article suggests prerequisites to coaching program applications as well as learning approaches to help coaches embrace the power dynamics associated with their intervention.
Thinking Like a Professional: The Impact of Graduate Coach Education
Authors: Campone Francine
Published: July 2014

Coaches are practicing within an increasingly complex context: a globalized world, a hyper‐complex society, and diversification of knowledge sources (Stelter, ), requiring the situationally appropriate exercise of judgment (Murphy, ). Graduate professional education programs transmit the necessary technical knowledge (the “how” of coaching) and cultivate proficiency in reflective evaluation of context in order to apply that technical knowledge (the principles and decision protocols of coaching). This article explores the impact of one graduate coach education program, the Evidence‐Based Coaching Certificate (EBC) program at Fielding Graduate University, on the professional judgments of program graduates. Results indicate three different catalysts for coach judgments: client characteristics, coaching tasks, and elements of the coaching engagement (including time frames, expected outcomes, organizational or other situational contexts). Through reflective learning, coaches gained insights into four aspects of their coaching: managing boundaries and ethical challenges, self‐awareness and self‐management, understanding responsive processes, and situational application of theory.
Virtual Group Coaching: A Curriculum for Coaches and Educators
Authors: Van Dyke Pamela R.
Published: July 2014

Virtual group coaching exists at the intersection of coaching and the group experience. At a high level, virtual group coaching can be defined as exploring the coaching process with a group of individuals who are being coached by a professional coach utilizing the vehicle of group process to accomplish the goals and objectives of the individual. Currently, there exist no guidelines or standards for group coaching regarding approach or educational curriculum. As the field of coaching matures and evolves, investigating and gaining an understanding of what coaches need to know in order to effectively coach a virtual group will be not only helpful but necessary. Insights found in this article have been gained from both the author's research and experience as a group coach.
Dual/wide band multifractal frequency selective surface for applications in S‐ and X‐band
Authors: Braz Erico C. , Campos Antonio. L. P. S.
Published: July 2014

In this article, we have been investigated the use of frequency selective surfaces (FSS) with multifractal geometry. The proposed structure is a junction of the Koch curve with Sierpinski Carpet. The main advantage of the proposed structure is to design multiband FSS makes it flexible in terms of controlling resonance and bandwidth. In addition, the proposed structure produces multiple frequency ratios between adjacent bands and an easy to implement structure. The validation of the proposed structure was initially verified through simulations in Ansoft designer 3.5 and then the structures are constructed and experimental results obtained. A good agreement between numerical and experimental results is obtained. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2217–2222, 2014
Reducing glitches when reconstructing four‐port S‐parameters of differential transmission lines from two‐port measurements
Authors: García‐Mora Daniel M. , Tlaxcalteco‐Matus Miguel A. , Torres‐Torres Reydezel , Hernández‐Sosa Gaudencio , Becerra‐Fuentes Olga M.
Published: July 2014

The origin of the glitches observed in four‐port S‐parameters reconstructed from two‐port measured data is identified, allowing their direct minimization without any data post‐processing. Excellent correlation for the obtained four‐port and mixed‐mode S‐parameters is achieved when confronted with those directly measured using a four‐port network analyzer. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2257–2260, 2014
UWB bandpass filter with quad notched bands
Authors: Sung Y. J.
Published: July 2014

A novel ultrawideband (UWB) bandpass filter (BPF) with a quad band‐notched function is investigated using a modified H‐shaped resonator. The proposed H‐shaped resonator, which exhibits quadruple resonance characteristics, is realized without any change in its overall size by modifying the simplified composite right/left‐handed resonator exhibiting dual resonance characteristics. The proposed resonator is integrated into a conventional UWB BPF. The notching frequencies are located at 2.41, 3.42, 5.3, and 5.9 GHz, and the attenuations at the center frequency of the four notched bands are at least 13 dB. The proposed UWB BPF has the advantages of compact size, low insertion loss, good selectivity, and flat delays. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2286–2289, 2014
FBG‐assisted ICI reduction for AO‐OFDM demultiplexed signal
Authors: Ali Mumtaz , Wang Xu
Published: July 2014

In an all‐optical orthogonal frequency division multiplexing (AO‐OFDM) system, the demultiplexed subcarriers from an optical discrete fourier transform circuit are needed to be sampled by optical gates in the intercarrier interference (ICI)‐free narrow interval. In this article, we present a theoretical investigation of fiber Bragg grating (FBG) assisted ICI reduction in an AO‐OFDM system in place of an optical sampling gate (SG). The optimum durations of SG and FBG are analyzed for different symbol rise times (trise) and the analysis is extended to chromatic dispersion (CD) effects. The proposed FBG device provides tolerance to dispersion, which causes shifting of narrowed ICI‐free region. The FBG achieves BER < 10−3 for transmission of 45 km without cyclic prefix, and synchronization with shifted ICI‐free region is not needed. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2320–2324, 2014
Characterization of transistor using multiharmonic source and load pull tuners for inverse class‐F power amplifier
Authors: Gao Shengjie , Wang Zhebin , Park Chan‐Wang
Published: July 2014

To achieve a first‐pass design for a high efficiency inverse class‐F power amplifier, this article proposes a characterization procedure using the multiharmonic source and load pull tuner system. The transistor is analyzed in terms of the power added efficiency and the output power by considering harmonic frequencies. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2313–2320, 2014
Demonstration of 100 Gbit/s optical time‐division demultiplexing with 1‐to‐4 wavelength multicasting using the cascaded four‐wave mixing in photonic crystal fiber with a single control light source
Authors: Hui Zhan‐Qiang , Zhang Jian‐Guo
Published: July 2014

Dispersion‐flattened highly nonlinear (DF‐HNL) photonic crystal fibers are useful for ultrafast optical signal processing. In this article, 100 Gbit/s‐to‐10 Gbit/s optical time demultiplexing with simultaneous 1‐to‐4 wavelength multicasting is successfully demonstrated by use of the cascaded four‐wave mixing (FWM) in a 50 m DF‐HNL photonic crystal fiber, for the first time. This scheme uses a single control‐pulse light source only and a simple architecture. The wavelength multicasting of the time‐demultiplexed optical signal is achieved on four wavelength channels of which two can have the minimum power penalty of 3.2 dB at 10−9 bit error rate compared to the 10 Gbit/s back‐to‐back measurement. With the cascaded FWM, our proposed scheme can be used to improve the functionality of ultrahigh‐speed optical time‐division multiplexed systems/networks so as to support wavelength multicasting applications in a cost‐effective manner. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2330–2335, 2014
Design and implementation of intrabody communication hub/alarm unit in IBC platform for fall prevention system
Authors: Lin Yo‐Sheng , Wang Chien‐Chin , Liao Yu‐Chen , Lu Shey‐Shi
Published: July 2014

We report a high‐performance intrabody communication (IBC) hub/alarm unit in IBC platform for fall prevention system. The IBC hub/alarm unit consists of a binary frequency shift keying (BFSK) receiver, an on–off keying (OOK) transmitter, an audio digital‐to‐analog converter (DAC), an audio power amplifier (PA), and a microcontrol unit (MCU). The BFSK receiver receives the biomedical signals from the IBC sensor node biomedical system‐on‐a‐chips (SOC) through human body, and then transmits them to PDA/cell phone or earphone alarm terminal through the MCU. The OOK transmitter takes commands from PDA/cell phone, and then transmits them to the IBC sensor node biomedical SOC through human body. The audio DAC and PA send an alarm message to the earphone in case of anomaly based on the biomedical signals received by the BFSK receiver. Such kind of transmission methodology in conjunction with our proposed IBC platform is much more power‐efficient than wireless communication. Moreover, since no antenna is required, small chip size is achieved. At supply voltage of 0.7 V, the BFSK receiver consumes 520 µW (0.17 nJ/b) and achieves sensitivity of −80 dBm at data rate of 3 Mbps, better than previous work in the literature. The excellent results indicate the IBC hub/alarm unit is suitable for IBC platform for fall prevention system. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2345–2351, 2014
High‐gain circularly‐polarized loop tag antenna for long reading distance RFID application
Authors: Tsai Ching‐Han , Chen Horng‐Dean , Sim Chow‐Yen‐Desmond
Published: July 2014

A simple circularly polarized (CP) square loop antenna for UHF band RFID tag is proposed to overcome the polarization mismatch problem between reader antenna and tag antenna. To achieve good CP radiation, an open gap is introduced onto the square loop. Also, the technique of loading a matching stub across the RFID chip is applied to the proposed loop tag antenna, and good impedance matching between the antenna and RFID chip can be achieved by tuning the matching stub. The proposed loop tag antenna shows desirable antenna gain and good reading distance performance, and its measured reading distance reaches to 17.6 m. Therefore, the proposed antenna is an excellent candidate for various RFID applications in the UHF band, especially those that may require long reading distance. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2335–2341, 2014
Temperature sensor based on frequency‐coded chipless RFID tags
Authors: Lorenzo Javier , Girbau David , Lázaro Antonio , Villarino Ramón
Published: July 2014

In this article, the integration of a frequency‐coded radio frequency identification tag with an integrated temperature sensor long lifetime is proposed. It is demonstrated that temperature range can be measured and coded in a tag using tunable stub‐loaded dual‐band resonator that is connected between two orthogonal wideband antennas. The sensor tag emits two different frequencies: the first resonance is used for identification of sensor tag whereas the second frequency is equivalent to temperature. The second resonance is tuned with a varactor controlled by a negative temperature coefficient sensor and its low‐power consumption conditioning circuit. The conditioning circuit modifies the voltage of the varactor and this modifies the second resonant frequency. The resonant structure is studied as a proof of concept. Experimental results at different distances are provided. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2411–2415, 2014
Design of cascaded three‐conductor coupled line filter
Authors: Packiaraj D. , Vinoy K. J. , Ramesh M. , Kalghatgi Ajit T.
Published: July 2014

This article presents analysis approach and applications of symmetrical three‐conductor coupled microstriplines with aperture in the ground plane for the design of microwave filters. Analysis is based on splitting the entire symmetrical three‐conductor coupled line structure into simple two‐conductor coupled lines. Various possible terminations have been shown in three‐conductor coupled lines to derive a class of structures for the construction of filters. These coupled line structures are analyzed based on even‐ and odd‐mode propagation characteristics to design filters in this article. An experimental cascaded three‐conductor coupled line band stop filter with defected ground has been designed using the method of circuit model analysis. Defected ground has been used under the coupled lines to widen the filter's bandwidth. Measured results of the designed band stop filter have been compared against the circuit model analysis for the purpose of validation. Results are in good agreement between them. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2431–2436, 2014
Magnetic resonance imaging of melanoma exosomes in lymph nodes
Authors: Hu Lingzhi , Wickline Samuel A. , Hood Joshua L.
Published: July 2014

Purpose

Exosomes are cell derived extracellular nanovesicles that relay molecular signals pertinent to both normal physiologic and disease processes. The ability to modify and track exosomes in vivo is essential to understanding exosome pathogenesis, and for utilizing exosomes as effective diagnostic and therapeutic nanocarriers to treat diseases.

Methods

We recently reported a new electroporation method that allow exosomes to be loaded with superparamagnetic iron oxide nanoparticles for magnetic resonance tracking.

Results

Building on this approach, we now demonstrate for the first time using a C57BL/6 mouse model that melanoma exosomes can be imaged in vitro, and within lymph nodes in vivo with the use of standard MRI approaches.

Conclusion

These findings demonstrate proof of principle that exosome biology can be followed in vivo and pave the way for the development of future diagnostic and therapeutic applications. Magn Reson Med 74:266–271, 2015. © 2014 Wiley Periodicals, Inc.
Using peer critique to promote learning
Authors: Newman Carole
Published: July 2014

The purpose of this Writer's Forum is to suggest a peer critique strategy and to present a rubric that can help students become more self‐regulated learners who are capable of carefully assessing their own work and who can benefit from specific feedback provided by a critical friend. Too often assignment directions are not completely followed resulting in incomplete learning, lower grades, and frustration on the part of both the student and teacher who are forced to spend additional time rewriting and re‐correcting. By becoming skilled in how to use a rubric to guide their efforts and by learning how to benefit from suggestions made by a critical friend, students have an increased opportunity to help each other as they work together toward the successful completion of assignments. Potential challenges along with potential solutions and benefits are also discussed.
Stimuli‐triggered phase transfer of polymer‐inorganic hybrid hairy particles between two immiscible liquid phases
Authors: Bao Chunhui , Horton Jonathan M. , Bai Zhifeng , Li Dejin , Lodge Timothy P. , Zhao Bin
Published: July 2014

Polymer brush‐grafted particles (i.e., hairy particles) capable of undergoing direct, especially reversible, phase transfer from one liquid phase to another immiscible liquid phase in response to environmental changes have received growing interest due to their great potential in a wide variety of applications. This article is intended to review recent exciting advances in stimuli‐triggered phase transfer of hairy particles in liquid‐liquid biphasic systems. We start with a discussion of the mechanism of particle transfer across a liquid‐liquid interface and progress to the synthesis of polymer brushes grafted on particles and the transfer of hairy particles between two immiscible liquid phases induced by various external stimuli, including temperature, pH, ionic strength, light, and solvents. The applications of thermally triggered phase transfer of hairy particles in catalysis (thermoregulated phase transfer catalysis) are discussed, followed by a summary and our perspective on future development. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 1600–1619
High animal fat intake enhances prostate cancer progression and reduces glutathione peroxidase 3 expression in early stages of TRAMP mice
Authors: Chang Seo‐Na , Han Juhee , Abdelkader Tamer Said , Kim Tae‐Hyoun , Lee Ji Min , Song Juha , Kim Kyung‐Sul , Park Jong‐Hwan , Park Jae‐Hak
Published: July 2014

BACKGROUND

Prostate cancer is the most frequently diagnosed cancer in Western men, and more men have been diagnosed at younger ages in recent years. A high‐fat Western‐style diet is a known risk factor for prostate cancer and increases oxidative stress.

METHODS

We evaluated the association between dietary animal fat and expression of antioxidant enzymes, particularly glutathione peroxidase 3 (GPx3), in the early stages of transgenic adenocarcinoma of the mouse prostate (TRAMP) mice. Six‐week‐old male nontransgenic and TRAMP mice were placed on high animal fat (45% Kcal fat) or control (10% Kcal fat) diets and sacrificed after 5 or 10 weeks.

RESULTS

The histopathological score increased with age and high‐fat diet consumption. The histopathological scores in dorsal and lateral lobes increased in the 10‐week high‐fat diet group (6.2 ± 0.2 and 6.2 ± 0.4, respectively) versus the 10‐week control diet group (5.3 ± 0.3 and 5.2 ± 0.2, respectively). GPx3 decreased both at the mRNA and protein levels in mouse prostate. GPx3 mRNA expression decreased (∼36.27% and ∼23.91%, respectively) in the anterior and dorsolateral prostate of TRAMP mice fed a high‐fat diet compared to TRAMP mice fed a control diet. Cholesterol treatment increased PC‐3 human prostate cancer cell proliferation, decreased GPx3 mRNA and protein levels, and increased H2O2 levels in culture medium. Moreover, increasing GPx3 mRNA expression by troglitazone in PC‐3 cells decreased cell proliferation and lowered H2O2 levels.

CONCLUSIONS

Dietary fat enhances prostate cancer progression, possibly by suppressing GPx3 expression and increasing proliferation of prostate intraepithelial neoplasia (PIN) epithelial cells. Prostate 74: 1266–1277, 2014. © 2014 Wiley Periodicals, Inc.
Simultaneous targeting of prostate stem cell antigen and prostate‐specific membrane antigen improves the killing of prostate cancer cells using a novel modular T cell‐retargeting system
Authors: Arndt Claudia , Feldmann Anja , Koristka Stefanie , Cartellieri Marc , Dimmel Maria , Ehninger Armin , Ehninger Gerhard , Bachmann Michael
Published: July 2014

BACKGROUND

Recently, we described a novel modular platform technology in which T cell‐recruitment and tumor‐targeting domains of conventional bispecific antibodies are split to independent components, a universal effector module (EM) and replaceable monospecific/monovalent target modules (TMs) that form highly efficient T cell‐retargeting complexes. Theoretically, our unique strategy should allow us to simultaneously retarget T cells to different tumor antigens by combining the EM with two or more different monovalent/monospecific TMs or even with bivalent/bispecific TMs, thereby overcoming limitations of a monospecific treatment such as the selection of target‐negative tumor escape variants.

METHODS

In order to advance our recently introduced prostate stem cell antigen (PSCA)‐specific modular system for a dual‐targeting of prostate cancer cells, two additional TMs were constructed: a monovalent/monospecific TM directed against the prostate‐specific membrane antigen (PSMA) and a bivalent/bispecific TM (bsTM) with specificity for PSMA and PSCA. The functionality of the novel dual‐targeting strategies was analyzed by performing T cell activation and chromium release assays.

RESULTS

Similar to the PSCA‐specific modular system, the novel PSMA‐specific modular system mediates an efficient target‐dependent and ‐specific tumor cell lysis at low E:T ratios and picomolar Ab concentrations. Moreover, by combination of the EM with either the bispecific TM directed to PSMA and PSCA or both monospecifc TMs directed to either PSCA or PSMA, dual‐specific targeting complexes were formed which allowed us to kill potential escape variants expressing only one or the other target antigen.

CONCLUSIONS

Overall, the novel modular system represents a promising tool for multiple tumor targeting. Prostate 74: 1335–1346, 2014. © 2014 Wiley Periodicals, Inc.
GP guide to the diagnosis and management of conjunctivitis
Authors: Chen Jern Yee , Tey Adrian
Published: July 2014

There are several causes of conjunctivitis and it is important to make the correct diagnosis to avoid complications. In our Drug review the authors describe the clinical features and recommended management of conjunctivitis, followed by an analysis of prescription data.
Hybrid Crystals Comprising Metal–Organic Frameworks and Functional Particles: Synthesis and Applications
Authors: Li Shaozhou , Huo Fengwei
Published: July 2014

Hybrid crystals containing encapsulated functional species exhibit promising novel physical and chemical properties. The realization of many properties critically depends on the selection of suitable functional species for incorporation, the rational control of the crystallinity of the host materials, and the manipulation of the distribution of the encapsulated species; only a few hybrid crystals achieve this. Here, a novel synthetic method enables the encapsulation of functional species within crystalline metal–organic frameworks (MOFs). Various kinds of single‐crystalline MOFs with incorporated particles are presented. The encapsulated particles can be distributed in a controllable manner, and the hybrid crystals are applied to the heterogeneous catalysis of the reduction of nitroarenes. These findings suggest a general approach for the construction of MOF materials with potential applications; by combining species and MOFs with suitable functionalities, new properties—not possible by other means—may arise.
Isomeric Routes to Schiff‐Base Single‐layered Covalent Organic Frameworks
Authors: Liu Xuan‐He , Mo Yi‐Ping , Yue Jie‐Yu , Zheng Qing‐Na , Yan Hui‐Juan , Wang Dong , Wan Li‐Jun
Published: July 2014

With graphene‐like topology and designable functional moieties, single‐layered covalent organic frameworks (sCOFs) have attracted enormous interest for both fundamental research and application prospects. As the growth of sCOFs involves the assembly and reaction of precursors in a spatial defined manner, it is of great importance to understand the kinetics of sCOFs formation. Although several large families of sCOFs and bulk COF materials based on different coupling reactions have been reported, the synthesis of isomeric sCOFs by exchanging the coupling reaction moieties on precursors has been barely explored. Herein, a series of isomeric sCOFs based on Schiff‐base reaction is designed to understand the effect of monomer structure on the growth kinetics of sCOFs. The distinctly different local packing motifs in the mixed assemblies for the two isomeric routes closely resemble to those in the assemblies of monomers, which affect the structural evolution process for highly ordered imine‐linked sCOFs. In addition, surface diffusion of monomers and the molecule‐substrate interaction, which is tunable by reaction temperature, also play an important role in structural evolutions. This study highlights the important roles of monomer structure and reaction temperature in the design and synthesis of covalent bond connected functional nanoporous networks.
Endogenous calcium buffering at photoreceptor synaptic terminals in salamander retina
Authors: Van Hook Matthew J. , Thoreson Wallace B.
Published: July 2014

Calcium operates by several mechanisms to regulate glutamate release at rod and cone synaptic terminals. In addition to serving as the exocytotic trigger, Ca2+ accelerates replenishment of vesicles in cones and triggers Ca2+‐induced Ca2+ release (CICR) in rods. Ca2+ thereby amplifies sustained exocytosis, enabling photoreceptor synapses to encode constant and changing light. A complete picture of the role of Ca2+ in regulating synaptic transmission requires an understanding of the endogenous Ca2+ handling mechanisms at the synapse. We therefore used the “added buffer” approach to measure the endogenous Ca2+ binding ratio (κendo) and extrusion rate constant (γ) in synaptic terminals of photoreceptors in retinal slices from tiger salamander. We found that κendo was similar in both cell types—∼25 and 50 in rods and cones, respectively. Using measurements of the decay time constants of Ca2+ transients, we found that γ was also similar, with values of ∼100 s−1 and 160 s−1 in rods and cones, respectively. The measurements of κendo differ considerably from measurements in retinal bipolar cells, another ribbon‐bearing class of retinal neurons, but are comparable to similar measurements at other conventional synapses. The values of γ are slower than at other synapses, suggesting that Ca2+ ions linger longer in photoreceptor terminals, supporting sustained exocytosis, CICR, and Ca2+‐dependent ribbon replenishment. The mechanisms of endogenous Ca2+ handling in photoreceptors are thus well‐suited for supporting tonic neurotransmission. Similarities between rod and cone Ca2+ handling suggest that neither buffering nor extrusion underlie differences in synaptic transmission kinetics. Synapse 68:518–528, 2014. © 2014 Wiley Periodicals, Inc.
Fruit consumption and seed dispersal by birds in native vs. ex situ individuals of the endangered Chinese yew, Taxus chinensis
Authors: Li Ning , An Shu‐qing , Liu Zhao , Lu Chang‐hu
Published: July 2014

The conservation success of endangered trees may depend on re‐establishing or replacing the mutualisms that were important in their native habitats. In this study, we quantified avian frugivore diversity on individuals of the endangered Chinese yew (Taxus chinensis) in a botanical garden and at a natural site. We found that frugivore species diversity was lower in the botanical garden than in the natural site. In spite of the relatively low frugivore diversity, however, the ex‐situ population of Chinese yew attracted similar disperser species to those in the natural population, and trees in the ex‐situ population were visited more frequently than those in the natural population. Furthermore, the different perching behavior of dispersers resulted in different dispersal efficiencies. Although the Chinese bulbul (Pycnonotus sinensis) was the most common forager in the botanical garden, its dispersal efficiency was the lowest, and thus it could not like the role played by the mountain bulbul (Hypsipetes maclellandii) in the natural site. Only the red‐billed blue magpie (Urocissa erythrorhyncha) provided a high‐quality dispersal service in both sites. Our results highlight the ability of the Chinese yew to recruit seed dispersal agents in new habitats. However, if the newly recruited species is a low‐quality disperser, the plants will depend more heavily on other avian vectors for regeneration.
Let’s talk strategy: the impact of voluntary strategy disclosure on the cost of equity capital
Authors: Sieber Tom , Weißenberger Barbara E. , Oberdörster Tatjana , Baetge Jörg
Published: July 2014

This paper deals with the impact of voluntary strategy disclosure in management reports on the cost of equity capital. Such an impact is not obvious, as investors might consider strategy information as “cheap talk” and therefore ignore it. We analyze a sample of 100 German listed firms from 2002 to 2008, measuring strategy disclosure levels using hand-collected strategy disclosure scores. We find that higher disclosure levels are, on average, associated with lower cost of equity capital even after controlling for overall disclosure quality. The paper contributes to the field by providing evidence that voluntary strategy disclosures in firms’ management reports reduce the information asymmetry component of cost of capital and therefore can be considered as a relevant source of information for investors.
Screening‐based discovery of Aspergillus fumigatus plant‐type chitinase inhibitors
Authors: Lockhart Deborah E.A. , Schuettelkopf Alexander , Blair David E. , van Aalten Daan M.F.
Published: July 2014

A limited therapeutic arsenal against increasing clinical disease due to Aspergillus spp. necessitates urgent characterisation of new antifungal targets. Here we describe the discovery of novel, low micromolar chemical inhibitors of Aspergillus fumigatus family 18 plant‐type chitinase A1 (AfChiA1) by high‐throughput screening (HTS). Analysis of the binding mode by X‐ray crystallography confirmed competitive inhibition and kinetic studies revealed two compounds with selectivity towards fungal plant‐type chitinases. These inhibitors provide new chemical tools to probe the effects of chitinase inhibition on A. fumigatus growth and virulence, presenting attractive starting points for the development of further potent drug‐like molecules.
Structural features of peptoid–peptide hybrids in lipid–water interfaces
Authors: Uggerhøj Lars Erik , Munk Jens K. , Hansen Paul R. , Güntert Peter , Wimmer Reinhard
Published: July 2014

The inclusion of peptoid monomers into antimicrobial peptides (AMPs) increases their proteolytic resistance, but introduces conformational flexibility (reduced hydrogen bonding ability and cis/trans isomerism). We here use NMR spectroscopy to answer how the insertion of a peptoid monomer influences the structure of a regular α‐helical AMP upon interaction with a dodecyl phosphocholine (DPC) micelle. Insertion of [(2‐methylpropyl)amino]acetic acid in maculatin‐G15 shows that the structural change and conformational flexibility depends on the site of insertion. This is governed by the micelle interaction of the amphipathic helices flanking the peptoid monomer and the side chain properties of the peptoid and its preceding residue.
Stratified shear flow: experiments in an inclined duct
Authors: Meyer Colin R. , Linden P. F.
Published: July 2014

We present results of experiments on stratified shear flow in an inclined duct. The duct connects two reservoirs of fluid with different densities, and contains a counterflow with a dense layer flowing beneath a less dense layer moving in the opposite direction. We identify four flow states in this experiment, depending on the fractional density differences, characterised by the dimensionless Atwood number, and the angle of inclination $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}\theta $, which is defined to be positive (negative) when the along-duct component of gravity reinforces (opposes) the buoyancy-induced pressure differences across the ends of the duct. For sufficiently negative angles and small fractional density differences, the flow is observed to be laminar ($\mathsf{L}$ state), with an undisturbed density interface separating the two layers. For positive angles and/or high fractional density differences, three other states are observed. For small angles of inclination, the flow is wave-dominated and exhibits Holmboe modes ($\mathsf{H}$ state) on the interface, with characteristic cusp-like wave breaking. At the highest positive angles and density differences, there is a turbulent ($\mathsf{T}$ state) high-dissipation interfacial region typically containing Kelvin–Helmholtz (KH)-like structures sheared in the direction of the mean shear and connecting both layers. For intermediate angles and density differences, an intermittent state ($\mathsf{I}$ state) is found, which exhibits a rich range of spatio-temporal behaviour and an interfacial region that contains features of KH-like structures and of the other two lower-dissipation states: thin interfaces and Holmboe-like structures. We map the state diagram of these flows in the Atwood number–$\theta $ plane and examine the force balances that determine each of these states. We find that the $\mathsf{L}$ and $\mathsf{H}$ states are hydraulically controlled at the ends of the duct and the flow is determined by the pressure difference associated with the density difference between the reservoirs. As the inclination increases, the along-slope component of the buoyancy force becomes more significant and the $\mathsf{I}$ and $\mathsf{T}$ states are associated with increasing dissipation within the duct. We replot the state space in the Grashof number–$\theta $ phase plane and find the transition to the $\mathsf{T}$ state is governed by a critical Grashof number. We find that the corresponding buoyancy Reynolds number of the transition to the $\mathsf{T}$ state is of the order of 100, and that this state is also found to be hydraulically controlled at the ends of the duct. In this state the dissipation balances the force associated with the along-slope component of buoyancy and the counterflow has a critical composite Froude number.