bluuebunny/crossref_metadata_2025 huggingface dataset:
Vertical off‐centering affects organ dose in chest CT: Evidence from Monte Carlo simulations in anthropomorphic phantoms
Authors: Saltybaeva Natalia , Alkadhi Hatem
Published: August 2017

Purpose

The objective of our study was to assess the effect of patient vertical off‐centering on organ dose in chest CT with tube current modulation.

Methods

For this purpose, anthropomorphic phantoms representing adult male, female, and overweight male were scanned on 192‐slice CT scanner at 11 different vertical positions (maximal off‐centering ± 5 cm). Monte Carlo simulations were performed for each of the investigated setup, using tube current values extracted from the raw data, in order to obtain 3D dose distributions. Organ doses were calculated as a function of vertical off‐centering and compared with the reference values, calculated for the phantoms positioned in the gantry isocenter. Image noise was also calculated as a function of phantoms vertical position using few circular regions of interest. Pearson statistical analysis was used to determine the correlation coefficient between image noise and organ dose values with vertical off‐centering.

Results

Results of our study showed a significant difference in tube currents applied by the CT scanner when the phantom was scanned in off‐centered vertical positions compared to those obtained when the phantom was positioned in the gantry isocenter (P < 0.005). For all investigated phantom configurations the vertical off‐centering below 20 mm in both directions resulted in relative organ dose differences below 7%, while the off‐centering above 40 mm was associated with higher organ dose changes of about 20%. The highest relative dose difference of 38% was observed for the thyroid gland at the lowest table positions. A significant correlation between organ doses for breasts, heart, lungs, thyroid, and liver, and vertical off‐centering (R2 = 0.909–0.998, P < 0.005) was found. The relative dose increase associated with lower table position was more pronounced in peripheral organs: breast and thyroid gland. Image noise behaved opposite to the tube current and organ doses and increased at higher table positions.

Conclusion

Strong vertical off‐centering in chest CT with tube current modulation results in misoperation of the TCM function affecting both radiation dose and image noise. Therefore, special attention must be paid to a correct patient positioning in order to optimize organ doses and image quality of the respective CT examination.
Effect of meso‐structure on strength and size effect in concrete under tension
Authors: Murali K. , Deb Arghya
Published: August 2017

The effect of heterogeneity in meso level geometric and material properties on tensile strength and size effect in split cylinder specimens is investigated. Critical meso geometric parameters are identified by studying their influence on the evolution of the fracture process zone. A statistical analysis is used to account for dependencies between the parameters. A reversal of the size effect, important for the strength of field specimens, is observed for certain meso geometries. Meso level explanations for this are proposed, and meso geometries likely to show such a reversal are identified. For moderately sized specimens, major trends in the size effect are seen to be almost entirely explained by heterogeneity in the meso geometry.
Plasma Membrane Protein Profiling in Beta‐Amyloid‐Treated Microglia Cell Line
Authors: Correani Virginia , Di Francesco Laura , Mignogna Giuseppina , Fabrizi Cinzia , Leone Stefano , Giorgi Alessandra , Passeri Alessia , Casata Roberto , Fumagalli Lorenzo , Maras Bruno , Schininà M.Eugenia
Published: August 2017

In the responsiveness of microglia to toxic stimuli, plasma membrane proteins play a key role. In this study we treated with a synthetic beta amyloid peptide murine microglial cells metabolically differently labelled with stable isotope amino acids (SILAC). The plasma membrane was selectively enriched by a multi‐stage aqueous two‐phase partition system. We were able to identify by 1D‐LC‐MS/MS analyses 1577 proteins, most of them are plasma membrane proteins according to the Gene Ontology annotation. An unchanged level of amyloid receptors in this data set suggests that microglia preserve their responsiveness capability to the environment even after 24‐h challenge with amyloid peptides. On the other hand, 14 proteins were observed to change their plasma membrane abundance to a statistically significant extent. Among these, we proposed as reliable biomarkers of the inflammatory microglia phenotype in AD damaged tissues MAP/microtubule affinity‐regulating kinase 3 (MARK3), Interferon‐induced transmembrane protein 3 (IFITM3), Annexins A5 and A7 (ANXA5, ANXA7) and Neuropilin‐1 (NRP1), all proteins known to be involved in the inflammation processes and in microtubule network assembly rate.
Pre‐sowing seed treatment with cold plasma and electromagnetic field increases secondary metabolite content in purple coneflower (Echinacea purpurea) leaves
Authors: Mildaziene Vida , Pauzaite Giedre , Naucienė Zita , Malakauskiene Asta , Zukiene Rasa , Januskaitiene Irena , Jakstas Valdas , Ivanauskas Liudas , Filatova Irina , Lyushkevich Veronika
Published: August 2017

The effects of seed treatment with cold plasma (2–7 min), vacuum (7 min), and electromagnetic field (5–15 min) on Echinacea purpurea germination and performance are studied. All treatments induce faster germination but did not change the final germination percentage, except the decrease evoked by vacuum treatment. The plants grown from all groups of treated seeds have larger height, develop more leaves, some treatments increase root weight. The content of vitamin C and phenolic acids in extracts of plant leaves from the treated groups is substantially higher in comparison to the control, so that the amount of cichoric acid per plant increased up to 3.8‐fold, and amount of vitamin C per plant – up to 1.9‐fold. Seed treatments induce large increase in radical scavenging activity (up to 114%) in leaf extracts.
Jet‐to‐jet interactions in atmospheric‐pressure plasma jet arrays for surface processing
Authors: Liu Feng , Zhang Bo , Fang Zhi , Wan Meng , Wan Hui , Ostrikov Kostya (Ken)
Published: August 2017

Atmospheric Pressure Plasma Jet (APPJ) arrays are considered as one of the most promising methods for uniform plasma processing of large uneven surfaces. To improve the downstream uniformity and enhance the surface treatment effects, it is important to reveal the mechanisms of the jet‐to‐jet interactions of plasma plumes in the jet array. In this paper, the electrical, optical, and fluid characteristics of the He and Ar three‐channel one‐dimensional (1D) plasma jet arrays with cross‐field needle‐ring electrode structure are studied and compared. It is found that there are divergences in the outside plumes of the propagation trajectory by the repellency of the plasma bullets and the spatial uniformity of the He and Ar plasma jet arrays can be improved with a lower applied voltage and a higher gas flow rate. The deflection angle of side plumes with respect to the central one of He is larger than that of Ar jet array due to the lighter molecular weight and better discharge synchronization. The experimental results show that Ar jet array is more controllable and stable and is more suitable for the design of the practical, simpler, and cheaper scalable plasma jet arrays.
Description of Radiation Damage in Diamond Sensors Using an Effective Defect Model
Authors: Kassel Florian , Guthoff Moritz , Dabrowski Anne , de Boer Wim
Published: August 2017

The Beam Condition Monitoring Leakage (BCML) system is a beam monitoring device in the CMS experiment at the LHC consisting of 32 poly‐crystalline (pCVD) diamond sensors. The BCML sensors, located in rings around the beam, are exposed to high particle rates originating from the colliding beams. These particles cause lattice defects, which act as traps for the ionized charge carrier leading to a reduced charge collection efficiency (CCE). The radiation induced CCE degradation was, however, much more severe than expected from low rate laboratory measurements. Measurement and simulations presented in this paper show that this discrepancy is related to the rate of incident particles. At high particle rates, the trapping rate of the ionization is strongly increased compared to the detrapping rate leading to an increased build‐up of space charge. This space charge locally reduces the internal electric field increasing the trapping rate and hence reducing the CCE even further. In order to connect these macroscopic measurements with the microscopic defects acting as traps for the ionization charge, the TCAD simulation program SILVACO was used. It allows to introduce the defects as effective donor and acceptor levels, and can calculate the electric field from Transient Current Technique (TCT) signals and CCE as a function of the effective trap properties, like density, energy level, and trapping cross section. After each irradiation step, these properties were fitted to the data on the electric field from the TCT signals and CCE. Two effective acceptor and donor levels were needed to fit the data after each step. It turned out that the energy levels and cross sections could be kept constant and the trap density was proportional to the cumulative fluence of the irradiation steps. The highly non‐linear rate dependent diamond polarization and the resulting signal loss can be simulated using this effective defect model and is in agreement with the measurement results.
Tuning Color Temperature of White OLEDs in Parallel Tandems
Authors: Oliva Jorge , Papadimitratos Alexios , de la Rosa Cruz Elder , Zakhidov Anvar
Published: August 2017

Color‐temperature tunable white organic light emitting diodes (WOLEDs) in parallel tandem configuration were fabricated by using TFB:MEH‐PPV (yellow emitter) in the bottom subunit and TBADN (blue emitter) in the top subunit. In this parallel tandem architecture, a thin film of silver was an active common anode, which permitted to inject holes into top and bottom subunits simultaneously. This common injection electrode also allowed to tune the color temperature (CCT) and CIE coordinates of white light emission from cool (CIE: 0.33, 0.25; CCT = 5218 K) to warm (CIE: 0.38, 0.39; CCT = 3926 K) by controlling the brightness of the yellow light and blue light emitted in the bottom and top subunits respectively. The performance of the parallel tandem was compared with that of in‐series tandems and additional advantages of the parallel architecture such as tunable chromaticity, lower turn on voltage (4 V compared to 7 V in the in‐series tandem) and higher brightness (∼15%) were found. The closest CIE coordinate obtained for white light was (0.35, 0.35), which is near to the ideal coordinate of (0.33, 0.33) for pure white light. Thus, the results indicate that these white OLEDs in parallel configuration can be potentially useful for displays and lighting applications.
The role of weak interactions in characterizing peptide folding preferences using a QTAIM interpretation of the Ramachandran plot (ϕ‐ψ)
Authors: Momen Roya , Azizi Alireza , Wang Lingling , Yang Ping , Xu Tianlv , Kirk Steven R. , Li Wenxuan , Manzhos Sergei , Jenkins Samantha
Published: August 2017

The original Ramachandran plot is a potent way to understand structures of biomolecules, however only backbone conformations are considered. We formulate a new interpretation of the original Ramachandran plot (ϕ‐ψ) that can include a description of the weaker interactions including both the hydrogen bonds and HH bonds as a new way to derive insights into the phenomenon of peptide folding. Specifically, we show that QTAIM analysis permits identifying key regions of the Ramachandran plot without the need for massive data sets. The QTAIM interpreted Ramachandran plot is derived from QTAIM eigenvectors and not a trivial coordinate transformation. An investigation of both the backbone and the weaker bonds within the framework of the QTAIM interpreted Ramachandran plot was found to be in line with physical intuition. The least‐preferred directions calculated for the hydrogen bonds and HH bonds were found to coincide with the “unlikely” regions of the Ramachandran plot.
Systematic Knowledge Sharing in a Natural Hazard Damage Context: How Organizational Borders Limit Lessons Learned
Authors: Rydstedt Nyman Monika , Johansson Magnus , Liljegren Eva
Published: August 2017

The aim of this paper is to increase knowledge about systematic lessons learning in a public–private partnership. Empirically, it focuses on road maintenance in Sweden where the Swedish Transport Administration (STA) is responsible for the state‐owned infrastructure and tendered contractors carry out all maintenance. The tendering process stipulates that the stakeholders should enable learning and the knowledge transfer that is, by necessity, required for preventive purposes. Semi‐structured interviews with project leaders from the STA and respondents from two tendering contractors of maintenance were used to investigate attitudes to and the understanding of sharing experiences and knowledge about damage caused by weather extremes and the relevance of climate change adaptation in their field. The analysis suggests that most of the respondents’ experiences stay within their own organization, which creates parallel feedback loops, rather than becomes shared knowledge that could be used as lessons learned enhancing preventive work against future damage and loss. The analysis indicates imbalance in feedback of knowledge concerning weather extremes and their effects.
Exploiting code division multiplexing with decentralized multiuser detection in the satellite multibeam forward link
Authors: De Gaudenzi Riccardo , Alagha Nader , Angelone Martina , Gallinaro Gennaro
Published: August 2017

In recent years, the need for increased satellite throughput has been tackled by extending the number of satellite beams thus allowing a higher spectrum reuse and peak throughput. However, the satellite antenna size and the number of simultaneous beams that can be generated onboard over a given coverage region cannot grow beyond certain limits because of payload accommodation constraints. The next step being pursued to increase the system throughput resides in extending the frequency reuse among the loaded beams and to mitigate the effects of the increased co‐channel interference through more advanced digital signal processing. This can be achieved in 2 different ways. The first one, which received a large attention in recent years, is to centrally mitigate the multibeam channel cross talk by exploiting precoding techniques at the gateway. The second approach, less investigated in the past, is to put in place decentralized multiuser detection (MUD) at the user terminal side. The precoding approach has the advantage of concentrating the extra processing complexity at the gateway, but it requires nonstandard payloads or accurate payload calibration techniques and periodic channel estimation reporting from the user terminal. Instead, the decentralized approach can operate in combination with existing payloads and does not require any terminal's periodic channel estimate reporting to the gateway. Only the signal‐to‐noise plus interference variations due to possible fading as for conventional adaptive coding and modulation shall be reported. One of the main barriers to the decentralized MUD approach so far was the demodulator complexity. Some simplified approach for conventional frequency/time division multiplexing schemes has been recently published, and its applicability to the forward link investigated. In this paper, we investigate the possible advantages deriving from the adoption of direct‐sequence code division multiplexing associated with affordable complexity of the MUD at the user terminal side. It is shown that the proposed MUD scheme can be practically implemented and provides sizeable advantages compared to current state‐of‐the‐art when the traffic is not evenly distributed among the beams, ie, when a subset of beams has a higher load than the others.
Kinetic Studies of Bischloroimide Monomers for the Facile Synthesis of Different Molecular Architecture Poly(phthalimide‐co‐naphthalimide)s
Authors: Mushtaq Nafeesa , Chen Guofei , Sidra Lala Rukh , Zhang Anjiang , Fang Xingzhong
Published: August 2017

A series of different molecular architecture (homo, random, block and gradient type) copolymers PI‐3(a–e) were synthesized by solution polycondensation. Three different bischloroimide monomers [bischlorophthalimide 2 a, bischloronaphthalimide 2 b and bischloro (naphthalimide‐phthalimide) 2 c] were prepared and reacted with 4,4′‐thiobisbenzenethiol by different synthetic routes. The chemical reactivity of these monomers 2(a–c) was examined by kinetic study of model compounds N‐phenyl‐4‐chloro‐1,8‐naphthalimide and N‐phenyl‐4‐chlorophthalimide using gas chromatography mass spectrometry (GC‐MS). The difference in chemical reactivity of monomers was utilized to design molecular architecture of copolymer, and the influence of comonomers sequence on copolymer properties is investigated. The synthesized copolyimides PI‐3(a–e) integrated the excellent properties of naphthalimide and phthalimide as good organosolubility, high glass transition temperature of 198–319 °C and good thermooxidative stability based on 5 % weight loss temperature of 492–524 °C and 480–532 °C in nitrogen and air, respectively. Gradient type sequence PI‐3 e offers a good combination of phthalimide and naphthalimide groups in copolymers for improved thermal and mechanical properties.
Synthesis, Characterization, Crystal Structure, and Stability of 2‐(5, 5‐dimethyl‐3‐oxocyclohex‐1‐en‐1‐yl) Hydrazinecarbothioamide: A Combined Experimental and Theoretical Study
Authors: Mehdi Sayed Hasan , Ghalib Raza Murad , Awasthi Shikha , Alshahateet Solhe F. , Hashim Rokiah , Sulaiman Othman , Pandey Sarvesh Kumar
Published: August 2017

This work presents the synthesis and characterization as well as crystal structure determination of a biologically relevant, chemically and medicinally interesting isolated solids‐state crystal structure of its ethanol inclusion compound, 2‐(5,5‐dimethyl‐3‐oxocyclohex‐1‐en‐1‐yl) Hydrazinecarbothioamide for the first time in the literature. The molecules pack itself in the crystal latticesviaintermolecular interactions. The stability due to the role of H‐bond(s) in the title compound and itspacked cell, were quantitatively investigated by topological analysis based on Bader′s quantum theory of atoms in molecules (QTAIM) to characterize these interactions. The chemical, as well as topological properties of the electron densities,ρ(r)of the title system and itspacked cellhave been studied using DFT approach. Chemical reactivity of both species has also been calculated using HOMO‐LUMO, ionization energy, hardness, and chemical potential along with their molecular electrostatic potential and total electron density plots. In order to gain better insight into the role of H‐bonding interaction(s), the theoretically investigated binding energies revealed thatcrystal within the lattice unit (packed cell) having more intermolecular stabilizing interactions has been found to be more stable than itsmolecular unitusing DFT method andab initiomodeling which is fairly supported by the experimentally predicted H‐bonding interaction(s) and QTAIM based topological parameters.
Chitosan‐Supported Copper(II) Schiff Base Complexes: Applications in Synthesis of 5‐Substituted 1H‐Tetrazoles and Oxidative Homo‐Coupling of Terminal Alkynes
Authors: Anuradha  , Layek Samaresh , Agrahari Bhumika , Pathak Devendra Deo
Published: August 2017

Two new Chitosan‐supported Schiff base complexes (CS@L1‐Cu) and (CS@L2‐Cu) have been synthesized. They are characterized by various spectroscopic and instrumental techniques such as Fourier transform infrared spectroscopy (FT‐IR), Ultravoilet‐visible spectroscopy (UV‐Vis), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), Field emission scanning electron microscopy (FESEM), Energy dispersiveX‐ray microscopy (EDX), Thermo gravimetric analysis/Differential thermal analysis (TGA/DTA), and atomic absorption spectroscopy (AAS) analysis.Thecomplex CS@L2‐Cu have been found to be efficient heterogeneous catalyst for the synthesis of 5‐substituted 1H‐tetrazoles from a series of oximes and sodium azide and also for oxidative homo‐coupling of terminal alkynes. The catalyst could be easily recovered from reaction mixture by simple filtration and recycled up to five times with no significant loss in its catalytic activity. The mercury poisoning test indicated that the catalysts are heterogeneous in nature. All products were isolated as white to off‐white and light yellow solids and characterized by1H and 13C NMR spectroscopy.
Iron Catalyzed Cascade Protocol for the Synthesis of Pyrrolo[1, 2‐a]quinoxalines: A Powerful Tool to Access Solid State Emissive Organic Luminophores
Authors: Lade Jatin J. , Patil Bhausaheb N. , Sathe Pratima A. , Vadagaonkar Kamlesh S. , Chetti Prabhakar , Chaskar Atul C.
Published: August 2017

An alluring iron catalyzed cascade process has been developed for the synthesis of pyrrolo[1, 2‐a]quinoxalines by using 1‐(2‐aminoaryl)pyrrole and arylacetic acids. This method involves oxidative decarboxylation of arylacetic acids into aromatic aldehydes followed by their condensation with 1‐(2‐aminoaryl)pyrrole. Optical properties of newly synthesized pyrrolo[1, 2‐a]quinoxaline derivatives have been systematically investigated in solution as well as in solid state.
Role of Anomalous Water Constraints in the Efficacy of Pharmaceuticals Probed by 1H Solid‐State NMR
Authors: Damron Joshua T. , Kersten Kortney M. , Pandey Manoj Kumar , Nishiyama Yusuke , Matzger Adam , Ramamoorthy Ayyalusamy
Published: August 2017

Water plays a complex and central role in determining the structural and reactive properties in numerous chemical systems. In crystalline materials with structural water, the primary focus is often to relate hydrogen bonding motifs to functional properties such as solubility, which is highly relevant in pharmaceutical applications. Nevertheless, understanding the full electrostatic landscape is necessary for a complete structure‐function picture. Herein, a combination of tools including 1H magic angle spinning NMR and X‐ray crystallography are employed to evaluate the local landscape of water in crystalline hydrates. Two hydrates of an anti‐leukemia drug mercaptopurine, which exhibit dramatically different dehydration temperatures (by 90 °C) and a three‐fold difference in the in vivo bioavailability, are compared. The results identify an electrosteric caging mechanism for a kinetically trapped water in the hemihydrate form, which is responsible for the dramatic differences in properties.
Dynamic slicing of concurrent AspectJ programs: An explicit context‐sensitive approach
Authors: Singh Jagannath , Mohapatra Durga Prasad
Published: August 2017

This paper presents a context‐sensitive dynamic slicing technique for the concurrent and aspectized programs. To effectively represent the concurrent aspect‐oriented programs, we propose an intermediate graph called the multithreaded aspect‐oriented dependence graph (MAODG). The MAODG is a dynamic graph generated from the execution trace of a given program with respect to a particular set of values given as an input. Interference dependencies between the statements are shown by a distinguished edge called the interference dependence edge in the MAODG. Based on this intermediate representation, we propose a precise and accurate dynamic slicing algorithm for the concurrent aspect‐oriented programs implemented using AspectJ. The proposed dynamic slicing algorithm is implemented in a slicing tool developed using the ASM framework. Several open source programs are studied and evaluated using the proposed technique along with some existing techniques. The experimentation shows that our proposed slicing algorithm generates slices of the same or smaller size, as compared with the existing algorithms. Furthermore, we found that the slice computation time is significantly less in our proposed algorithm, as compared with the existing algorithms.
How Can Digital Personal(ized) Books Enrich the Language Arts Curriculum?
Authors: Kucirkova Natalia
Published: August 2017

Digital personal(ized) books are a relatively recent addition to the rich repertoire of literacy resources available to pre‐K and elementary school teachers. This article summarizes the key ways in which personal(ized) books can enrich the language arts curriculum, drawing on a series of empirically based examples. The value of personalization in the digital stories is explained theoretically using the framework of fiveAs: autonomy, authorship, authenticity, attachment, and aesthetics. The fiveAs apply to personal(ized) stories created for, or by, young students and are used to generate some practical suggestions for future use of touchscreens in the classroom.
Advances in plasmon‐enhanced upconversion luminescence phenomena and their possible effect on light harvesting for energy applications
Authors: Khan M.A. , Idriss H.
Published: August 2017

The focus of the review is on the recent advances of inorganic materials used for upconversion luminescence as well as the effect of plasmonic metals on the efficiency of the overall system. Central to the review is the effect of these upconverting luminescence materials coupled with plasmonic metals on photovoltaic cells and photocatalysts performance. The diffuse nature of sun light on earth (low flux) and its weak energy (low frequency) are the main hurdles for practical applications related to energy‐intensive processes. Upconversion luminescence materials increase light energy (high frequency) with weak efficiency, and when combined with plasmonics (potentially providing high local light flux), the overall efficiency of the system can be improved. Examples in this review are exclusively based on lanthanide compounds as light‐converting devices and on Au and Ag as plasmonic metals. Due to the so called ‘lanthanides contraction,’ the f‐orbitals of lanthanide cations are shielded from the outside environment (chemical bonds) when compared to early transition metals. This and the many energy levels associated with these f‐orbitals make them (particularly the Ln3+ 4f10, 4f11, 4f12, and 4f13) the most suitable materials for multiple energy transfer systems so far. While upconversion luminescence was first observed over half a century ago, since the pioneering work of Auzel, coupling it with plasmonics has only attracted attention in the last few years, and a limited amount of work is currently available. This review has compiled representative work in the field with the aim to motivate researchers to exploit this concept, which is central to light–matter interaction, and its effect on chemical reactions relevant to energy and the environment. WIREs Energy Environ 2017, 6:e254. doi: 10.1002/wene.254

This article is categorized under:

Energy Research & Innovation > Science and Materials
The effects of nanomaterials on blood coagulation in hemostasis and thrombosis
Authors: Simak Jan , De Paoli Silvia
Published: August 2017

The blood coagulation balance in the organism is achieved by the interaction of the blood platelets (PLTs) with the plasma coagulation system (PCS) and the vascular endothelial cells. In healthy organism, these systems prevent thrombosis and, in events of vascular damage, enable blood clotting to stop bleeding. The dysregulation of hemostasis may cause serious thrombotic and/or hemorrhagic pathologies. Numerous engineered nanomaterials are being investigated for biomedical purposes and are unavoidably exposed to the blood. Also, nanomaterials may access vascular system after occupational, environmental, or other types of exposure. Thus, it is essential to evaluate the effects of engineered nanomaterials on hemostasis. This review focuses on investigations of nanomaterial interactions with the blood components involved in blood coagulation: the PCS and PLTs. Particular emphases include the pathophysiology of effects of nanomaterials on the PCS, including the kallikrein‐kinin system, and on PLTs. Methods for investigating these interactions are briefly described, and a review of the most important studies on the interactions of nanomaterials with plasma coagulation and platelets is provided. WIREs Nanomed Nanobiotechnol 2017, 9:e1448. doi: 10.1002/wnan.1448

This article is categorized under:

Implantable Materials and Surgical Technologies > Nanomaterials and Implants

Toxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials
Stimuli‐responsive liposomes for drug delivery
Authors: Lee Y. , Thompson D.H.
Published: August 2017

The ultimate goal of drug delivery is to increase the bioavailability and reduce the toxic side effects of the active pharmaceutical ingredient (API) by releasing them at a specific site of action. In the case of antitumor therapy, association of the therapeutic agent with a carrier system can minimize damage to healthy, nontarget tissues, while limit systemic release and promoting long circulation to enhance uptake at the cancerous site due to the enhanced permeation and retention effect (EPR). Stimuli‐responsive systems have become a promising way to deliver and release payloads in a site‐selective manner. Potential carrier systems have been derived from a wide variety of materials, including inorganic nanoparticles, lipids, and polymers that have been imbued with stimuli‐sensitive properties to accomplish triggered release based on an environmental cue. The unique features in the tumor microenvironment can serve as an endogenous stimulus (pH, redox potential, or unique enzymatic activity) or the locus of an applied external stimulus (heat or light) to trigger the controlled release of API. In liposomal carrier systems triggered release is generally based on the principle of membrane destabilization from local defects within bilayer membranes to effect release of liposome‐entrapped drugs. This review focuses on the literature appearing between November 2008–February 2016 that reports new developments in stimuli‐sensitive liposomal drug delivery strategies using pH change, enzyme transformation, redox reactions, and photochemical mechanisms of activation. WIREs Nanomed Nanobiotechnol 2017, 9:e1450. doi: 10.1002/wnan.1450

This article is categorized under:

Therapeutic Approaches and Drug Discovery > Emerging Technologies

Biology-Inspired Nanomaterials > Lipid-Based Structures

Nanotechnology Approaches to Biology > Nanoscale Systems in Biology
Organization of theFlavivirusRNAreplicase complex
Authors: Brand Carolin , Bisaillon Martin , Geiss Brian J.
Published: August 2017

Flaviviruses, such as dengue, Japanese encephalitis, West Nile, yellow fever, and Zika viruses, are serious human pathogens that cause significant morbidity and mortality globally each year. Flaviviruses are single‐stranded, positive‐senseRNAviruses, and encode two multidomain proteins,NS3andNS5, that possess all enzymatic activities required for genome replication and capping.NS3andNS5interact within virus‐induced replication compartments to form theRNAgenome replicase complex. Although the individual enzymatic activities of both proteins have been extensively studied and are well characterized, there are still gaps in our understanding of how they interact to efficiently coordinate their respective activities during positive‐strandRNAsynthesis and capping. Here, we discuss what is known about the structures and functions of theNS3andNS5proteins and propose a preliminaryNS3:NS5:RNAinteraction model based on a large body of literature about how the viral enzymes function, physical restraints betweenNS3andNS5, as well as critical steps in the replication process.WIREs RNA2017, 8:e1437. doi: 10.1002/wrna.1437

This article is categorized under:

RNA Interactions with Proteins and Other Molecules > Protein–RNA Interactions: Functional Implications

RNA in Disease and Development > RNA in Disease
Communication About Sexual Matters With Women Attending a Danish Fertility Clinic: A Descriptive Study
Authors: Eldridge Katrine Fiil , Giraldi Annamaria
Published: August 2017

Introduction

Several studies have shown that sexuality is an important aspect of life. Nevertheless, sexual matters are only rarely discussed between patients and doctors. Other studies have suggested that women undergoing fertility treatment compose a group of patients with low satisfaction in their sexual life.

Aim

To investigate how women at a fertility clinic desire and experience communication about sexual matters with doctors and to investigate the sexual function of these women.

Methods

A cross-sectional self-administered questionnaire survey of women attending a Danish fertility clinic over 4 months was performed. Descriptive statistics were calculated and presented as frequencies.

Main Outcome Measure

Communication about sexual matters with doctors included the women’s comfort, preferred and actual frequency of discussion, and initiation of the conversation. Sexual function included participants’ sexuality during the past year including certain sexual difficulties.

Results

Of the 201 participating women in the survey, most felt comfortable discussing sexual matters with doctors and preferred gynecologists for such discussions. There was a greater desire for communication than what was actually experienced by the women, and most wanted to initiate the conversation themselves. The women were less satisfied with their sexual life compared with a national control group, and they experienced sexual difficulties more often.

Conclusion

There is an unmet desire of women in fertility treatment for discussing sexual matters, and greater communication on this subject needs to be clinically implemented.

Eldridge KE, Giraldi A. Communication About Sexual Matters With Women Attending a Danish Fertility Clinic. A Descriptive Study. Sex Med 2017;5:e196–e202.
John Donne and Baroque Allegory
Authors: Grady Hugh
Published: August 2017

John Donne has been one of the most controversial poets in the history of English literature, his complexity and intellectualism provoking both praise and censure. In this major re-assessment of Donne's poetry, Hugh Grady argues that his work can be newly appreciated in our own era through Walter Benjamin's theory of baroque allegory. Providing close readings of The Anniversaries, The Songs and Sonnets, and selected other lyrics, this study reveals Donne as being immersed in the aesthetic of fragmentation that define both the baroque and the postmodernist aesthetics of today. Synthesizing cultural criticism and formalist analysis, Grady illuminates Donne afresh as a great poet for our own historical moment.
The Broken Ladder
Authors: Krishna Anirudh
Published: August 2017

Despite becoming a global economic force, why does India win so few Olympic medals and have so many people living in poverty? Why have opportunities not become available more broadly? How can growing individuals assist with the task of building a growing economy? Krishna presents a refreshingly unusual perspective of emergent realities, drawing on the stories of everyday lives, of people like you and me and those less privileged. Through decades-long investigations, living in villages and slum communities, the author presents eye-opening details of missed opportunities and immense untapped talent that can be harnessed, with tremendous consequences for equity and growth. Offering possible solutions for inequality and those in need, The Broken Ladder is a comprehensive and fascinating account of development strategies in a fast-growing, yet largely agrarian, developing economy.
Self-embeddings of Bedford–McMullen carpets
Authors: ALGOM AMIR , HOCHMAN MICHAEL
Published: August 2017

Let$F\subseteq \mathbb{R}^{2}$be a Bedford–McMullen carpet defined by multiplicatively independent exponents, and suppose that either$F$is not a product set, or it is a product set with marginals of dimension strictly between zero and one. We prove that any similarity$g$such that$g(F)\subseteq F$is an isometry composed of reflections about lines parallel to the axes. Our approach utilizes the structure of tangent sets of$F$, obtained by ‘zooming in’ on points of$F$, projection theorems for products of self-similar sets, and logarithmic commensurability type results for self-similar sets in the line.
Singular analytic linear cocycles with negative infinite Lyapunov exponents
Authors: SADEL CHRISTIAN , XU DISHENG
Published: August 2017

We show that linear analytic cocycles where all Lyapunov exponents are negative infinite are nilpotent. For such one-frequency cocycles we show that they can be analytically conjugated to an upper triangular cocycle or a Jordan normal form. As a consequence, an arbitrarily small analytic perturbation leads to distinct Lyapunov exponents. Moreover, in the one-frequency case where the$k$th Lyapunov exponent is finite and the$(k+1)$st negative infinite, we obtain a simple criterion for domination in which case there is a splitting into a nilpotent part and an invertible part.
The collapse of megafaunal populations in southeastern Brazil
Authors: Raczka Marco F. , Bush Mark B. , De Oliveira Paulo Eduardo
Published: August 2017

Whether humans or climate change caused the extinction of megafaunal populations is actively debated. Caves in the Lagoa Santa provide mixed assemblages of megafauna and human remains; however, it remains uncertain the extent to which humans and megafauna interacted or overlapped temporally. Here we present the first paleoecological record from lowland South America that tracks the decline of megafauna and its ecological implications. We provide a data set for pollen, charcoal, andSporormiella,from two lakes in southeastern Brazil that span the last 23,000 yr. The data showed reduced abundances ofSporormiellaand an inferred megafaunal population decline that began 18,000 yr ago, with the functional extinction occurring between 12,000 and 11,500 yr ago. Population declines coincided with wet events. The age of the final megafaunal decline is within the range of the first human occupation of the region. Our data are consistent with climate causing the population collapse, with humans preventing population recovery and inducing extinction. We did not observe some of the ecological repercussions documented at other sites and attributed to the megafaunal extinction. Habitat-specific ecological consequences of the extinction add to the heterogeneity of late Pleistocene and early Holocene landscapes.
RAMIFICATION IN KUMMER EXTENSIONS ARISING FROM ALGEBRAIC TORI
Authors: SHIMAKURA MASAMITSU
Published: August 2017

We describe the ramification in cyclic extensions arising from the Kummer theory of the Weil restriction of the multiplicative group. This generalises the classical theory of Hecke describing the ramification of Kummer extensions.
A SCHWARZ LEMMA FOR -HARMONIC MAPS AND THEIR APPLICATIONS
Authors: CHEN QUN , ZHAO GUANGWEN
Published: August 2017

We establish a Schwarz lemma for $V$-harmonic maps of generalised dilatation between Riemannian manifolds. We apply the result to obtain corresponding results for Weyl harmonic maps of generalised dilatation from conformal Weyl manifolds to Riemannian manifolds and holomorphic maps from almost Hermitian manifolds to quasi-Kähler and almost Kähler manifolds.
Who Controls Foreign Aid? Elite versus Public Perceptions of Donor Influence in Aid-Dependent Uganda
Authors: Findley Michael G. , Harris Adam S. , Milner Helen V. , Nielson Daniel L.
Published: August 2017

Does foreign aid enable or constrain elite capture of public revenues? Reflecting on prominent debates in the foreign aid literature, we examine whether recipient preferences are consistent with a view that foreign donors wield substantial control over the flow of aid dollars, making elite capture more difficult and mass benefits more likely. We compare elite and mass support for foreign aid versus government spending on development projects through a survey experiment with behavioral outcomes. A key innovation is a parallel experiment on members of the Ugandan national parliament and a representative sample of Ugandan citizens. For two actual aid projects, we randomly assigned different funders to the projects. Significant treatment effects reveal that members of parliament support government programs over foreign aid, whereas citizens prefer aid over government. Donor control also implies that citizens should favor foreign aid more and elites less as their perceptions of government clientelism and corruption increase. We explore this and report on other alternative mechanisms. Effects for citizens and elites are most apparent for those perceiving significant government corruption, suggesting that both sets of subjects perceive significant donor control over aid.
Impact of habitat degradation on species diversity and nest abundance of five African stingless bee species in a tropical rainforest of Kenya
Authors: Kiatoko Nkoba , Raina Suresh Kumar , van Langevelde Frank
Published: August 2017

Natural habitat degradation often involves the reduction or disappearance of bee species. In Africa, stingless bees are hunted for honey, which is used as food, for medicinal purposes, and for traditional rituals. Severe habitat degradation due to human settlement is hypothesized to have a negative impact on the species diversity of the African stingless bee species. In this paper, we assess the impact of habitat degradation on the diversity of five stingless bee species across different habitats in the tropical rainforest of Kenya (indigenous forest, mixed indigenous forest) and its neighbouring landscape (grassland, village) in western Kenya. The species fauna, nest occurrence, and species diversity of the stingless bee species varied across the different habitats. The number of nesting habitats of the meliponine species varied between habitats in the tropical rainforest.Meliponula ferruginea(reddish brown) nested in five habitats, whileMeliponula bocandeiandMeliponula ferruginea(black) nested only in two habitat types. The species richness decreased within the different types of habitats and the indigenous and mixed indigenous forest contained more species than other habitats. The fauna composition in both homesteads was exclusively similar, while the indigenous and mixed indigenous forests were mostly similar. Similarity in habitat preferences for nesting was revealed betweenM. bocandeivsPlebeina hildebrandtiandM. ferruginea(reddish brown) vsHypotrigona gribodoi. The natural native indigenous forest had the most diverse community compared to the degraded habitats. There are taxon-specific responses to habitat change; and in our study, there is clear value in conserving the native indigenous forest.
Comparison of the mitochondrial genomes of the Old and New World strains of the legume pod borer, Maruca vitrata (Lepidoptera: Crambidae)
Authors: Agunbiade Tolulope A. , Coates Brad S. , Sun Weilin , Tsai Mu-Rou , Valero Maria Carmen , Tamò Manuele , Pittendrigh Barry R.
Published: August 2017

Maruca vitrata(Fabricius, 1787) is a cryptic pantropical species of Lepidoptera that are comprised of two unique strains that inhabit the American continents (New World strain) and regions spanning from Africa through to Southeast Asia and Northern Australia (Old World strain). In this study, wede novoassembled the complete mitochondrial genome sequence of the New World legume pod borer,M. vitrata, from shotgun sequence data generated on an Illumina HiSeq 2000. Phylogenomic comparisons were made with other previously published mitochondrial genome sequences from crambid moths, including the Old World strain ofM.vitrata. The 15,385 bpM. vitrata(New World) sequence has an 80.7% A+T content and encodes the 13 protein-coding, 2 ribosomal RNA and 22 transfer RNA genes in the typical orientation and arrangement of lepidopteran mitochondrial DNAs. Mitochondrial genome-wide comparison between the New and Old World strains ofM. vitratadetected 476 polymorphic sites (4.23% nucleotide divergence) with an excess of synonymous substitution as a result of purifying selection. Furthermore, this level of sequence variation suggests that these strains diverged from ~1.83 to 2.12 million years ago, assuming a linear rate of short-term substitution. Thede novoassemblies of mitochondrial genomes from next-generation sequencing (NGS) reads provide readily available data for similar comparative studies.
Carer's perception of and reaction to reassurance seeking in obsessive compulsive disorder
Authors: Kobori Osamu , Salkovskis Paul M. , Pagdin Rowena , Read Julie , Halldorsson Brynjar
Published: August 2017

The purpose of the present study was to explore the experience of being asked for reassurance from the perspective of carers of obsessive compulsive disorder (OCD) sufferers, and to examine its relationship to sufferers’ reassurance seeking by a direct comparison with data obtained from the person they normally offer reassurance to. Forty-two individuals with OCD and their carers completed alternate versions of the Reassurance Seeking Questionnaire. Result suggest that carers report most commonly providing reassurance when asked to do so, and the frequency of their reassurance provision is associated with how carefully sufferers seek reassurance, rather than their OCD symptom severity. The carer's perspectives on the impact of reassurance provision was accurate; both sufferers and carers perceive that reassurance works only temporarily, but even if the anxiety-relieving effect of reassurance decreases in the medium term, it is likely to be perceived as beneficial because carers accurately perceived that sufferers would feel much worse if they refused to provide reassurance. The present study is the first to quantitatively investigate carer's experiences of reassurance provision, and elucidate why carers feel the need to provide it.
Giant Ragweed (Ambrosia trifida) Emergence Model Performance Evaluated in Diverse Cropping Systems
Authors: Goplen Jared J. , Sheaffer Craig C. , Becker Roger L. , Moon Roger D. , Coulter Jeffrey A. , Breitenbach Fritz R. , Behnken Lisa M. , Gunsolus Jeffrey L.
Published: August 2017

Accurate weed emergence models are valuable tools for scheduling planting, cultivation, and herbicide applications. Multiple models predicting giant ragweed emergence have been developed, but none have been validated in diverse crop rotation and tillage systems, which have the potential to influence weed emergence patterns. This study evaluated the performance of published giant ragweed emergence models across various crop rotations and spring tillage dates in southern Minnesota. Across experiments, the most robust model was a mixed-effects Weibull (flexible sigmoidal function) model predicting emergence in relation to hydrothermal time accumulation with a base temperature of 4.4 C, a base soil matric potential of −2.5 MPa, and two random effects determined by overwinter growing degree days (GDD) (10 C) and precipitation accumulated during seedling recruitment. The deviations in emergence between individual plots and the fixed-effects model were distinguished by the positive association between the lower horizontal asymptote (Drop) and maximum daily soil temperature during seedling recruitment. This finding indicates that crops and management practices that increase soil temperature will have a shorter lag phase at the start of giant ragweed emergence compared with practices promoting cool soil temperatures. Thus, crops with early-season crop canopies such as perennial crops and crops planted in early spring and in narrow rows will likely have a slower progression of giant ragweed emergence. This research provides a valuable assessment of published giant ragweed emergence models and illustrates that accurate emergence models can be used to time field operations and improve giant ragweed control across diverse cropping systems.
How to Find an Iceberg’s Breaking Point
Authors: Witman Sarah
Published: August 2017

Researchers develop a mathematical method of modeling tabular icebergs, like the one that broke away from an Antarctic ice shelf earlier this year.
Simulations Give New View of Global Auroral Storms
Authors: Zastrow Mark
Published: August 2017

New computer models capture the movement of the strongest auroral storms as they sweep across Earth at night, challenging scientists’ views of what drives them.