bluuebunny/crossref_metadata_2025_split huggingface dataset:
Probing the Self‐Assembled Nanostructures of Functional Polymers with Synchrotron Grazing Incidence X‐Ray Scattering
Authors: Ree Moonhor 
Published: April 2014

For advanced functional polymers such as biopolymers, biomimic polymers, brush polymers, star polymers, dendritic polymers, and block copolymers, information about their surface structures, morphologies, and atomic structures is essential for understanding their properties and investigating their potential applications. Grazing incidence X‐ray scattering (GIXS) is established for the last 15 years as the most powerful, versatile, and nondestructive tool for determining these structural details when performed with the aid of an advanced third‐generation synchrotron radiation source with high flux, high energy resolution, energy tunability, and small beam size. One particular merit of this technique is that GIXS data can be obtained facilely for material specimens of any size, type, or shape. However, GIXS data analysis requires an understanding of GIXS theory and of refraction and reflection effects, and for any given material specimen, the best methods for extracting the form factor and the structure factor from the data need to be established. GIXS theory is reviewed here from the perspective of practical GIXS measurements and quantitative data analysis. In addition, schemes are discussed for the detailed analysis of GIXS data for the various self‐assembled nanostructures of functional homopolymers, brush, star, and dendritic polymers, and block copolymers. Moreover, enhancements to the GIXS technique are discussed that can significantly improve its structure analysis by using the new synchrotron radiation sources such as third‐generation X‐ray sources with picosecond pulses and partial coherence and fourth‐generation X‐ray laser sources with femtosecond pulses and full coherence.
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Polymer Brushes on Planar TiO2 Substrates
Authors: Yang Jiming , Hou Liman , Xu Bin , Zhang Ning , Liang Yongjiu , Tian Wenjing , Dong Dewen 
Published: April 2014

A facile and universal method is presented for the preparation of polymer brushes on amorphous TiO2 film. Homogeneous and stable poly(methyl methacrylate), polystyrene, poly(4‐vinylpyridine), and poly(N‐vinyl imidazole) (PNVI) brushes up to 550 nm are directly created onto TiO2 via UV‐induced photopolymerization of corresponding monomers. Kinetic studies reveal a linear increase in thickness with the polymerization time. Characterization of the resulting polymer brushes by FTIR spectroscopy, X‐ray photoelectron spectroscopy, contact angle, and atomic force microscopy (AFM) indicates an efficient UV‐grafting reaction. Finally, we have demonstrated the possibility in converting the PNVI brushes to poly(vinyl imidazolium bromide), i.e., poly(ionic liquid) brushes by polymer–analogous reactions.
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Ambient Temperature Ligation of Diene Functional Polymer and Peptide Strands onto Cellulose via Photochemical and Thermal Protocols
Authors: Tischer Thomas , Claus Tanja K. , Oehlenschlaeger Kim K. , Trouillet Vanessa , Bruns Michael , Welle Alexander , Linkert Katharina , Goldmann Anja S. , Börner Hans G. , Barner‐Kowollik Christopher 
Published: April 2014

In the present contribution, two novel ambient temperature avenues are introduced to functionalize solid cellulose substrates in a modular fashion with synthetic polymer strands (poly(trifluoro ethyl methacrylate), PTFEMA, Mn = 4400 g mol−1, Đ = 1.18) and an Arg‐Gly‐Asp (RGD) containing peptide sequence. Both protocols rely on a hetero Diels–Alder reaction between an activated thiocarbonyl functionality and a diene species. In the first—thermally activated—protocol, the cellulose features surface‐expressed thiocarbonylthio compounds, which readily react with diene terminal macromolecules at ambient temperature. In the second protocol, the reactive ene species are photochemically generated based on a phenacyl sulfide‐decorated cellulose surface, which upon irradiation expresses highly reactive thioaldehyde species. The generated functional hybrid surfaces are characterized in‐depth via ToF‐SIMS and XPS analysis, revealing the successful covalent attachment of the grafted materials, including the spatially resolved patterning of both synthetic polymers and peptide strands using the photochemical protocol. The study thus provides a versatile platform technology for solid cellulose substrate modification via efficient thermal and photochemical ligation strategies.
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Nano‐Layered Inorganic‐Organic Hybrid Materials for the Controlled Delivery of Antimicrobials
Authors: Kinninmonth Malcolm , Liauw Christopher M. , Verran Joanna , Taylor Rebecca L. , Edwards‐Jones Valerie , Shaw David 
Published: April 2014

SummaryAn essential oil (EO) blend has been identified that provides a broad spectrum potent antimicrobial effect. Adsorption of the EO onto porous silicate materials (Rockwood Additives: Laponite® B, Laponite® RD and Fulcat® 800) and has been analysed and it was found that Laponite® RD organically modified with dihydrogenated tallow dimethyl ammonium chloride (2HT2M) at 50% cation exchange capacity gave the highest levels of adsorption. The Laponite® RD 2HT2M with EO blend adsorbed has been added to polymer materials to produce an antimicrobial polymer. The adsorption of the EO onto the Laponite® RD was done to achieve controlled release of the EO to prolong the antimicrobial effect within the polymer.Addition of the EO loaded substrates into silicone elastomer has resulted in successfully conferring a high level of antimicrobial activity to the polymer.
Poly(propylene)/Fly Ash Composites: Effect of Coupling Agents on Mechanical Properties and Matrix Crystallinity
Authors: Iraola‐Arregui Itziar , Liauw Christopher Mark , Potgieter Herman 
Published: April 2014

SummaryPoly(propylene) homopolymer/fly ash (50%wt) composites have been prepared from two samples of fly ash. One of the samples has a greater soluble group I and II metal content. A screening study indicated that Lubrizol Solplus® C800 (an unsaturated carboxylic acid coupling agent), initiated with dicumyl peroxide (DCP), conferred the best strength–toughness balance to composites produced by small scale batch mixing followed by compression moulding, i.e. long residence time in the melt. In the latter case, however the good mechanical properties were related to detachment of the interfacial region due to possible extraction of PP‐C800 adduct‐group I and II ion reaction products. Interfacial adhesion was arguably too high in the case of the fly ash sample bearing a lower level of group I and II ions. These deductions were also supported by DSC data. However, higher shear ‐ low residence time processing, i.e. by twin screw extrusion and injection moulding, led to better mechanical properties being obtained from C800‐DCP modification when the fly ash contained a reduced level of soluble group I and II ions.
Associations between individual lower urinary tract symptoms and bacteriuria in random urine samples in women
Authors: Sorrentino Felice , Cartwright Rufus , Digesu G. Alessandro , Tolton Louise , Franklin Larissa , Singh Anand , Greco Pantaleo , Khullar Vik 
Published: April 2014

AbstractAimsPrevious studies have noted an association between a diagnosis of overactive bladder and bacteriuria, but little is understood about the relationship of bacteriuria to specific LUTS. We hypothesized that bacteriuria in women would be associated with increased self‐reported symptom scores for a wide range of LUTS.MethodsWomen were recruited from general gynecology and urogynecology outpatient clinics in a secondary care setting. Women completed the 12‐item International Consultation on Incontinence Questionnaire for Female Lower Urinary Tract Symptoms and provided a clean‐catch mid‐stream specimen of urine for microscopy and culture. Women with acute urinary tract infection were excluded. Three statistical approaches (Mann–Whitney U‐test, multivariable logistic regression, and receiver operating characteristic curves) were used to assess differences in symptom scores between women with and without bacteriuria.ResultsTwo hundred forty‐seven women were recruited, aged 22–82. Sixteen of 247 urine samples (6.5%) demonstrated significant bacteriuria, growing a different range of organisms. Women with significant bacteriuria were more likely to have nocturia (OR 3.56, 95% CI 1.19–10.6, P = 0.02), urgency (OR 6.66, 95% CI 1.47–30.06, P = 0.01), bladder pain (OR 2.82, 95% CI 1–7.92, P = 0.049), urgency incontinence (OR 2.92, 95% CI 1.02–8.36, P = 0.046), nocturnal enuresis (OR 4.21, 95% CI 1.32–13.41, P = 0.01). After adjustment for age, parity, symptomatic prolapse, menopausal status and history of mid‐urethral sling urinary urgency, bladder pain, nocturia, and nocturnal enuresis remained significantly associated.ConclusionsBacteriuria is associated with a range of LUTS including nocturia, urgency, and bladder pain supporting a role for bacterial colonization in the pathogenesis of OAB symptoms. Neurourol. Urodynam. 34:429–433, 2015. © 2014 Wiley Periodicals, Inc.
The Removal of Ear Trophies Associated with Scalpings in Prehistoric North Alabama
Authors: De Vore W. E. , Jacobi K. P. 
Published: April 2014

AbstractThe act of scalping has long been associated with Native American conflict‐related human body part trophy taking. Reasons for their removal were varied and often included communal and personal factors. Previous research has identified several different types of scalp removals based on the amount of soft tissue affected during the process of scalping. One of these types can involve the removal of the ears. Through reanalysis of known scalping victims within the middle Tennessee Valley of North Alabama, we have identified five cases where victims were both scalped and had their ears removed. These cases provide a unique understanding of the practice of human body part trophy taking. They support ethnographic accounts that indicate ear removal has great time depth and was geographically widespread. Although the five cases presented here are similar to total compound scalpings, they actually represent total simple scalpings. Unlike total compound scalpings, where the ears are removed attached to the skin of the scalp, these cases show evidence of secondary removal of the ears after the scalp was already detached. This secondary removal of the ears after the act of scalping supports the interpretation that the aggressors intended different purposes for each trophy. It is likely that the scalp and ears each had their own meaning. Copyright © 2014 John Wiley & Sons, Ltd.
A Mid Upper Palaeolithic Child Burial from Borsuka Cave (Southern Poland)
Authors: Wilczyński J. , Szczepanek A. , Wojtal P. , Diakowski M. , Wojenka M. , Sobieraj D. 
Published: April 2014

AbstractDuring the excavation in the Borsuka Cave site (southern Poland), extraordinary materials were obtained for the study of the Mid Upper Palaeolithic (MUP) settlement in the region. In layer VI, six deciduous teeth of a modern Homo sapiens infant were discovered together with 112 pendants made from the teeth of European elk and steppe wisent or aurochs. The teeth appear to belong to a 12‐ to 18‐month‐old child. The sex of the child cannot be determined. Diagnostic features of the teeth and the fact that they all represent the same developmental phase suggest that they belong to a single individual. In this paper, we put forward a number of alternative explanations for why only a child's teeth and numerous pendants were deposited in the late Pleistocene sediments of Borsuka Cave, for example, natural factors (carnivore activity), human habitation, existence of a pendant workshop in the vicinity of the cave and intentional burial. Although no traces of a burial pit were encountered, intentional burial, the oldest known from Poland, is indicated by the presence of human remains together with numerous ornaments and absence of ‘domestic’ finds, such as lithic cores, debitage and tools. An unusual presence of a larger number of pierced teeth of large herbivores in a child burial is noticeable among assorted mortuary practices recorded in MUP Central Europe. Copyright © 2014 John Wiley & Sons, Ltd.
Building Blocks for the Construction of Bioorthogonally Reactive Peptides via Solid‐Phase Peptide Synthesis
Authors: Zeglis Brian M. , Emmetiere Fabien , Pillarsetty Nagavarakishore , Weissleder Ralph , Lewis Jason S. , Reiner Thomas 
Published: April 2014

AbstractThe need for post‐synthetic modifications and reactive prosthetic groups has long been a limiting factor in the synthesis and study of peptidic and peptidomimetic imaging agents. In this regard, the application of biologically and chemically orthogonal reactions to the design and development of novel radiotracers has the potential to have far‐reaching implications in both the laboratory and the clinic. Herein, we report the synthesis and development of a series of modular and versatile building blocks for inverse electron‐demand Diels–Alder copper‐free click chemistry: tetrazine‐functionalized artificial amino acids. Following the development of a novel peptide coupling protocol for peptide synthesis in the presence of tetrazines, we successfully demonstrated its effectiveness and applicability. This versatile methodology has the potential to have a transformational impact, opening the door for the rapid, facile, and modular synthesis of bioorthogonally reactive peptide probes.
Synthesis and characterization of poly(3‐hexylthiophene)–poly(3‐hexyloxythiophene) random copolymers with tunable band gap via Grignard metathesis polymerization
Authors: Yang Yi‐Lung , Lee Yi‐Huan , Lee Yu‐Ping , Chiang Chi‐Ju , Shen Ching , Wu Chun‐Ching , Ohta Yoshihiro , Yokozawa Tsutomu , Dai Chi‐An 
Published: April 2014

AbstractA series of 3‐substituted polythiophene copolymers having different side chain arrangements of hexyl and hexyloxy groups has been synthesized via the Grignard metathesis (GRIM) method and systematically studied. Despite differences in monomer reactivity ratios for the nickel‐catalyzed chain transfer polymerization, random sequences of hexyl‐ and hexyloxy‐substituted polythiophenes with different monomer compositions and adjustable band‐gap energies can be synthesized according to their respective comonomer feed ratio, as evidenced from NMR, UV, electrochemical measurements, and computational calculations. Structural characterization from X‐ray diffraction measurements reveals that the flexible hexyloxy side chains of the monomer significantly affect the crystallinity and molecular packing of the random copolymers. This study shows potential for synthesizing random copolymers with different monomer reactivities via the GRIM method for future optoelectronic applications. © 2014 Society of Chemical Industry
Replacing the Equations of Fano and Fisher for Cased Charge Blast Impulse – III – Yield Stress Method
Authors: Hutchinson Michael D. 
Published: April 2014

AbstractPrevious papers by the author [1–3] pointed to a discovery by Fisher [4] that an equation by Fano [5], when used to predict blast impulse from cased munitions, did not fit the available data. These previous papers showed that an alternative equation for casing‐modified blast impulse could be derived directly from an equation by Gurney [6] for the kinetic energy balance between the mass of casing metal and the mass of explosive gases. However, this equation was derived for very ductile casings that are accelerated to their ideal Gurney velocity before they fracture. A previous paper [3] showed how the finite fracture strain of real casing metal can be taken into account in determining the relative blast impulse from a cased charge. This paper shows how, based on previous work by Taylor [7], the equation in [2] can instead be modified to allow for the yield stress of the casing metal and provides validation for this further equation from available experimental data.
The Role of Fuel Particle Size on Flame Propagation Velocity in Thermites with a Nanoscale Oxidizer
Authors: Sullivan Kyle T. , Kuntz Joshua D. , Gash Alexander E. 
Published: April 2014

AbstractThe effect of aluminum size on confined flame propagation velocities in thermite composites was investigated between 108 μm and 80 nm, and in all cases using nanometric copper oxide as the oxidizer. It was found that the velocity exhibited two distinct regimes; between 108 and 3.5 μm the velocity scaled as the particle diameter to the − 0.56 power, and becomes invariant of size below this. One explanation for the invariance is that the pressure‐driven flow reaches some peak velocity, controlled by the pressure gradient, pore size, and fluid viscosity. Another explanation is that the system becomes limited by the internal gas heating rate, defined by the intrinsic kinetic time scale, and which can significantly impact the effective particle heating time. The particle heating time was calculated as a function of particle size, and as a function of gas heating rates ranging from 105 K s−1 to infinity. It was found that at any finite gas heating rate, there exists a critical particle diameter below which all sizes take the same amount of time to heat. This is a direct artifact of the characteristic thermal relaxation time scale; if the heating rate is not sufficiently fast, then the particle will rapidly equilibrate with the gas at each time step. The inverse of thermal relaxation time was used to calculate a critical heating rate defining a transition point, and which exhibits a dp2 scaling. This scaling sets a constraint on the kinetics, which must at least scale with dp2 to remain in the size‐dependent regime.
Crystal structure of the histone lysine specific demethylase LSD1 complexed with tetrahydrofolate
Authors: Luka Zigmund , Pakhomova Svetlana , Loukachevitch Lioudmila V. , Calcutt M. Wade , Newcomer Marcia E. , Wagner Conrad 
Published: April 2014

AbstractAn important epigenetic modification is the methylation/demethylation of histone lysine residues. The first histone demethylase to be discovered was a lysine‐specific demethylase 1, LSD1, a flavin containing enzyme which carries out the demethylation of di‐ and monomethyllysine 4 in histone H3. The removed methyl groups are oxidized to formaldehyde. This reaction is similar to those performed by dimethylglycine dehydrogenase and sarcosine dehydrogenase, in which protein‐bound tetrahydrofolate (THF) was proposed to serve as an acceptor of the generated formaldehyde. We showed earlier that LSD1 binds THF with high affinity which suggests its possible participation in the histone demethylation reaction. In the cell, LSD1 interacts with co‐repressor for repressor element 1 silencing transcription factor (CoREST). In order to elucidate the role of folate in the demethylating reaction we solved the crystal structure of the LSD1–CoREST–THF complex. In the complex, the folate‐binding site is located in the active center in close proximity to flavin adenine dinucleotide. This position of the folate suggests that the bound THF accepts the formaldehyde generated in the course of histone demethylation to form 5,10‐methylene‐THF. We also show the formation of 5,10‐methylene‐THF during the course of the enzymatic reaction in the presence of THF by mass spectrometry. Production of this form of folate could act to prevent accumulation of potentially toxic formaldehyde in the cell. These studies suggest that folate may play a role in the epigenetic control of gene expression in addition to its traditional role in the transfer of one‐carbon units in metabolism.
Thermoelectric properties of Mg2Si coatings deposited by pack cementation assisted process on heavily doped Si substrates
Authors: Stathokostopoulos D. , Stefanaki E. C. , Ioannou M. , Polymeris G. S. , Chaliampalias D. , Pavlidou E. , Kyratsi Th. , Paraskevopoulos K. M. , Vourlias G. , Hatzikraniotis E. 
Published: April 2014

This work presents a study of structural and thermoelectric properties of Mg2Si coatings deposited on heavily doped p‐ and n‐type Si substrates, at 650 °C. The as‐grown layers were smooth and uniform in thickness without any texture, voids, or large density of cracks. The sign of Seebeck coefficient in deposited layers follows the one of the corresponding substrate, indicating effective doping of the grown layers with the dopant already present in Si substrate (B for p‐type and As for n‐type). Doping levels of ∼9 × 1018 cm−3 for p‐type and ∼5 × 1018 cm−3 for n‐type, were obtained. IR reflectivity analysis revealed a strong mode at 272 cm−1 and a shoulder at 316 cm−1. Thermoelectric properties were successfully modeled by a multiple‐band model, with optical phonon scattering. Temperature dependence of electrical conductivity for the deposition layers. The lines represent the theoretical fitting.
A randomized phase I Bayesian dose escalation design for the combination of anti‐cancer drugs
Authors: Dejardin David , Lesaffre Emmanuel , Hamberg Paul , Verweij Jaap 
Published: April 2014

AbstractNowadays, treatment regimens for cancer often involve a combination of drugs. The determination of the doses of each of the combined drugs in phase I dose escalation studies poses methodological challenges. The most common phase I design, the classic ‘3+3' design, has been criticized for poorly estimating the maximum tolerated dose (MTD) and for treating too many subjects at doses below the MTD. In addition, the classic ‘3+3' is not able to address the challenges posed by combinations of drugs. Here, we assume that a control drug (commonly used and well‐studied) is administered at a fixed dose in combination with a new agent (the experimental drug) of which the appropriate dose has to be determined. We propose a randomized design in which subjects are assigned to the control or to the combination of the control and experimental. The MTD is determined using a model‐based Bayesian technique based on the difference of probability of dose limiting toxicities (DLT) between the control and the combination arm. We show, through a simulation study, that this approach provides better and more accurate estimates of the MTD. We argue that this approach may differentiate between an extreme high probability of DLT observed from the control and a high probability of DLT of the combination. We also report on a fictive (simulation) analysis based on published data of a phase I trial of ifosfamide combined with sunitinib.Copyright © 2014 John Wiley & Sons, Ltd.