bluuebunny/crossref_metadata_2025 huggingface dataset:
Implications of transient deformation in the northern Basin and Range, western United States
Authors: Chamoli Ashutosh , Lowry Anthony R. , Jeppson Tamara N.
Published: April 2014

Transient deformation events observed in Global Positioning System (GPS) data from the Basin and Range extensional province may illuminate qualitatively similar transient events observed in subduction zones and other tectonic environments. We model GPS time series at 22 sites using a combination of hyperbolic tangent function analysis and elastic load deformation estimated from climatological data. We identify two transient events, ~2000.4 and ~2004.4, with roughly similar timing and displacement to those described previously by other researchers. The first few years of GPS observations, adopted as a reference state in earlier studies, are found to be anomalous. Our results differ from previous studies in two respects. First, a significant component of northward transient motion occurs during both events, despite a reversal of sign in east component motion. Second, sites move coherently in the eastern as well as the western Basin and Range. Surface mass loading, the largest source of transient stress forcing in the region, exhibits no evidence of a simple relationship to the deformation transients. Prior studies inferred slip on a single megadetachment at the Moho, but that hypothesis assumes negligible ductile deformation of the lower crust and a dry olivine rheology for the uppermost mantle. Recent measurements of crustal quartz abundance and effective elastic thickness suggest both assumptions are unlikely. Basin and Range transients can be reconciled with the frictional slip mechanism widely accepted for subduction zone transients provided that slip is occurring on discontiguous detachment surfaces at midcrustal depths.
Interpreting subsurface volcanic structures using geologically constrained 3‐D gravity inversions: Examples of maar‐diatremes, Newer Volcanics Province, southeastern Australia
Authors: Blaikie T. N. , Ailleres L. , Betts P. G. , Cas R. A. F.
Published: April 2014

We present results and a method to geophysically image the subsurface structures of maar volcanoes to better understand eruption mechanisms and risks associated with maar‐forming eruptions. High‐resolution ground gravity and magnetic data were acquired across several maar volcanoes within the Newer Volcanics Province of southeastern Australia, including the Ecklin maar, Red Rock Volcanic Complex, and Mount Leura Volcanic Complex. The depth and geometry of subsurface volcanic structures were determined by interpretation of gridded geophysical data and constrained 2.5‐D forward and 3‐D inverse modeling techniques. Bouguer gravity lows identified across the volcanic craters reflect lower density lake sediments and pyroclastic debris infilling the underlying maar‐diatremes. These anomalies were reproduced during modeling by shallow coalesced diatremes. Short‐wavelength positive gravity and magnetic anomalies identified within the center of the craters suggest complex internal structures. Modeling identified feeder vents, consisting of higher proportions of volcanic debris, intrusive dikes, and ponded magma. Because potential field models are nonunique, sensitivity analyses were undertaken to understand where uncertainty lies in the interpretations, and how the models may vary between the bounds of the constraints. Rather than producing a single “ideal” model, multiple models consistent with available geologic information are created using different inversion techniques. The modeling technique we present focuses on maar volcanoes, but there are wider implications for imaging the subsurface of other volcanic systems such as kimberlite pipes, scoria cones, tuff rings, and calderas.
Proxy evidence for China's monsoon precipitation response to volcanic aerosols over the past seven centuries
Authors: Zhuo Zhihong , Gao Chaochao , Pan Yuqing
Published: April 2014

The effect of volcanic aerosols on China's monsoon precipitation over the past 700 years has been studied using two independently compiled histories of volcanism combined with the Monsoon Asia Drought Atlas. For both reconstructions, four categories of eruptions are distinguished based on the character of their Northern Hemisphere (NH) injection; then Superposed Epoch Analysis (SEA) with a 10,000 Monte Carlo resampling procedure is undertaken for each category and also each individual grid. Results show a statistically significant (at 90% confidence level) drying trend over mainland China from year 1 to year 4 after the eruptions, and the more sulfate aerosol that is injected into the NH stratosphere, the more severe this drying trend. In comparison, a minor wetting trend is observed in the years following Southern Hemisphere‐only injections. Results from spatial distribution of the SEA show (1) a southward movement of the significant dry areas in eastern China from year 0 to year 2 after volcanic perturbations that are either equal to or double the size of the 1991 Mount Pinatubo eruption (15 T sulfate aerosols in NH) and (2) northeast and northwest China experienced substantial droughts in years 2 to 5. These results are in good agreement with a SEA analysis of the Chinese Historical Drought Disaster Index compiled from historical meteorological records. Our findings illustrate the important role stratospheric aerosols have played in altering China's precipitation during the summer monsoon season and can shed new light on the possible effects that stratospheric geoengineering may have on China's precipitation.
Preoperative cerebrospinal fluid β‐Amyloid/Tau ratio and postoperative delirium
Authors: Xie Zhongcong , Swain Celeste A. , Ward Sarah A. P. , Zheng Hui , Dong Yuanlin , Sunder Neelakantan , Burke Dennis W. , Escobar Diana , Zhang Yiying , Marcantonio Edward R.
Published: April 2014

Objective

The neuropathogenesis of postoperative delirium remains unknown. Low cerebrospinal fluid (CSF) β‐amyloid protein (Aβ) and high CSF Tau levels are associated with Alzheimer's disease. We, therefore, assessed whether lower preoperative CSF Aβ/Tau ratio was associated with higher incidence and greater severity of postoperative delirium.

Methods

One hundred and fifty‐three participants (71 ± 5 years, 53% men) who had total hip/knee replacement under spinal anesthesia were enrolled. CSF was obtained during initiation of spinal anesthesia. The incidence and severity of postoperative delirium were determined by Confusion Assessment Method (CAM) and Memorial Delirium Assessment Scale (MDAS) on postoperative day 1 and 2. Aβ40, Aβ42, and Tau levels in the CSF were measured by enzyme‐linked immunosorbent assay. The relationships among these variables were determined, adjusting for age and gender.

Results

Participants in the lowest quartile of preoperative CSF Aβ40/Tau and Aβ42/Tau ratio had higher incidence (32% vs. 17%, P = 0.0482) and greater symptom severity of postoperative delirium (Aβ40/Tau ratio: 4 vs. 3, P = 0.034; Aβ42/Tau ratio: 4 vs. 3, P = 0.062, the median of the highest MDAS score) as compared to the combination of the rest of the quartiles. The preoperative CSF Aβ40/Tau or Aβ42/Tau ratio was inversely associated with MDAS score (Aβ40/Tau ratio: −0.12 ± 0.05, P = 0.014, adj. −0.12 ± 0.05, P = 0.018; Aβ42/Tau ratio: −0.65 ± 0.26, P = 0.013, adj. −0.62 ± 0.27, P = 0.022).

Interpretation

Lower CSF Aβ/Tau ratio could be associated with postoperative delirium, pending confirmation of our preliminary results in further studies. These findings suggest potential roles of Aβ and/or Tau in postoperative delirium neuropathogenesis.
Smokeless Tobacco (Moist Snuff) Use and the Risk of Developing Rheumatoid Arthritis: Results From a Case–Control Study
Authors: Jiang Xia , Alfredsson Lars , Klareskog Lars , Bengtsson Camilla
Published: April 2014

Objective

To investigate the association between snuff use (smokeless tobacco containing nicotine) and the risk of anti–citrullinated protein/peptide antibody (ACPA)–positive and ACPA‐negative rheumatoid arthritis (RA).

Methods

Data from the Swedish Epidemiological Investigation of Rheumatoid Arthritis, a population‐based case–control study including 1,998 incident cases and 2,252 randomly selected controls (matched on age, sex, and residential area) ages 18–70 years, were analyzed. Ever, current, and past moist snuff users were compared with never users. We calculated odds ratios (ORs) with 95% confidence intervals (95% CIs) by means of unconditional logistic regression models. All analyses were adjusted for cigarette smoking, alcohol consumption, and the matching variables.

Results

In total, 254 (13%) cases were ever moist snuff users compared with 290 (13%) controls, resulting in an OR of 1.0 (95% CI 0.8–1.2) of RA overall. When exposure to moist snuff was analyzed in relation to ACPA‐positive and ACPA‐negative disease, no associations were observed. Neither current nor past moist snuff use was related to the risk of any of the 2 RA subgroups. Analyses restricted to never smokers provided similar results.

Conclusion

The use of moist snuff was not associated with the risk of either ACPA‐positive or ACPA‐negative RA. The increased risk of RA associated with smoking is most probably not due to nicotine.
In Situ High Energy X‐Ray Diffraction for Investigating the Phase Transformation in Hot Rolled TRIP‐Aided Steels
Authors: Suwanpinij Piyada , Stark Andreas , Li Xiaoxiao , Römer Frank , Herrmann Klaus , Lippmann Thomas , Bleck Wolfgang
Published: April 2014

The phase transformation kinetics of a hot rolled transformation induced plasticity (TRIP) steel is investigated by means of in situ high energy X‐ray diffraction. The samples are deformed and annealed according to the parameters of a hot rolling process in a deformation dilatometer installed in the synchrotron beamline. Simultaneously, the phase fraction and the carbon content in the remaining austenite were measured by X‐ray diffraction. It is advantageous that the retained austenite (RA) can be measured without sample preparation, which usually results in unwanted strain‐induced martensite transformation. This study shows that enough carbon enrichment of austenite can be achieved by forming carbide free bainite. However, too little fraction of the RA for the TRIP effect can be formed without the pre‐deformation. The pre‐deformation also promotes the decarburization of the bainitic ferrite especially at high temperature.
Mechanism of Crystallization and Implications for Charge Transport in Poly(3‐ethylhexylthiophene) Thin Films
Authors: Duong Duc T. , Ho Victor , Shang Zhengrong , Mollinger Sonya , Mannsfeld Stefan C.B. , Dacuña Javier , Toney Michael F. , Segalman Rachel , Salleo Alberto
Published: April 2014

In this work, crystallization kinetics and aggregate growth of poly(3‐ethylhexylthiophene) (P3EHT) thin films are studied as a function of film thickness. X‐ray diffraction and optical absorption show that individual aggregates and crystallites grow anisotropically and mostly along only two packing directions: the alkyl stacking and the polymer chain backbone direction. Further, it is also determined that crystallization kinetics is limited by the reorganization of polymer chains and depends strongly on the film thickness and average molecular weight. Time‐dependent, field‐effect hole mobilities in thin films reveal a percolation threshold for both low and high molecular weight P3EHT. Structural analysis reveals that charge percolation requires bridged aggregates separated by a distance of ≈2–3 nm, which is on the order of the polymer persistence length. These results thus highlight the importance of tie molecules and inter‐aggregate distance in supporting charge percolation in semiconducting polymer thin films. The study as a whole also demonstrates that P3EHT is an ideal model system for polythiophenes and should prove to be useful for future investigations into crystallization kinetics.
Dissolution Behaviors and Applications of Silicon Oxides and Nitrides in Transient Electronics
Authors: Kang Seung‐Kyun , Hwang Suk‐Won , Cheng Huanyu , Yu Sooyoun , Kim Bong Hoon , Kim Jae‐Hwan , Huang Yonggang , Rogers John A.
Published: April 2014

Silicon oxides and nitrides are key materials for dielectrics and encapsulation layers in a class of silicon‐based high performance electronics that has ability to completely dissolve in a controlled fashion with programmable rates, when submerged in bio‐fluids and/or relevant solutions. This type of technology, referred to as “transient electronics”, has potential applications in biomedical implants, environmental sensors, and other envisioned areas. The results presented here provide comprehensive studies of transient behaviors of thin films of silicon oxides and nitrides in diverse aqueous solutions at different pH scales and temperatures. The kinetics of hydrolysis of these materials depends not only on pH levels/ion concentrations of solutions and temperatures, but also on the morphology and chemistry of the films, as determined by the deposition methods and conditions. Encapsulation strategies with a combination of layers demonstrate enhancement of the lifetime of transient electronic devices, by reducing water/vapor permeation through the defects.
Programmable Arrays of “Micro‐Bubble” Constructs via Self‐Encapsulation
Authors: Ye Chunhong , Kulkarni Dhaval D. , Dai Hongqi , Tsukruk Vladimir V.
Published: April 2014

The fabrication of ordered arrays of self‐encapsulated “micro‐bubble” material constructs based on the capillary‐driven collapse of flexible silk fibroin sheets during propagation of the diffusion front of the encapsulated material is demonstrated. The individual micro‐bubbles of different shapes are composed of a sacrificial material encapsulated within the ultrathin silk coating, which covers and seals the inner material during dissolution of supporting layer. The array of microscopic rectangular multi‐layer silk sheets on supporting polymer layers can be selectively dissolved along the edges to initiate their self‐encapsulation. The resulting micro‐bubble morphology, shape, and arrangements can be readily pre‐programmed by controlling the geometry of the silk sheets, such as thickness, dimension, and aspect ratio. These micro‐bubble constructs can be utilized for encapsulation of various materials as well as nanoparticles in a single or multi compartmental manner. These biocompatible and biodegradable micro‐bubble constructs present a promising platform for one‐shot spatial and controllable loading and locking material arrays with addressable abilities.
Selective 5‐exo‐dig Cyclization of in Situ Synthesized N‐Boc‐2‐aminophenyl Ethoxyethynyl Carbenols: Synthesis of Multifunctional Indoles and Their Derivatives
Authors: Thirupathi Nuligonda , Kumar Yalla Kiran , Kant Ruchir , Reddy Maddi Sridhar
Published: April 2014

A method to prepare 3‐substituted‐2‐formylindole derivatives from N‐Boc‐ortho‐aminoaryl ketones and ethoxyacetylene through a cascade of reactions in a single operation that included a nucleophile‐triggered 5‐exo‐dig cyclization and an acid‐mediated 1,3‐allyl alcohol isomerization (1,3‐AAI) is described. A variety of aryl, vinyl and alkynyl groups can be introduced at C‐3 of indole‐2‐carboxaldehyde while having a high functional group compatibility. The 3‐alkynyl adducts, which are highly valuable substrates for diversity‐oriented synthesis, can be further transformed to useful carboline and carbazole derivatives through novel pathways.

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Hydroxynitrile Lyase‐Catalyzed Synthesis of Enantiopure Cyanohydrins in Biocatalytic Active Static Emulsions (BASE) with Suppression of the Non‐Enzymatic Side Reaction
Authors: von Langermann Jan , Wapenhensch Stefanie
Published: April 2014

The use of biocatalytic active static emulsions (BASE) was investigated for the hydroxynitrile lyase‐catalyzed synthesis of enantiopure cyanohydrins. With this technique a full suppression of the undesired racemic non‐enzymatic side reaction was facilitated, even at unusually high pH within the aqueous phase. Thus the full catalytic potential at the optimum pH was achieved with the hydroxynitrile lyase from Manihot esculenta. As proof of principle, a series of carbonyl compounds was successfully converted to the corresponding cyanohydrins with high yields and enantioselectivities, including several benzaldehyde derivatives and aliphatic ketones. Furthermore, several mandelic acid derivatives were obtained on a multi‐gram scale after hydrolysis, which proves the synthetic applicability of BASE‐immobilized hydroxynitrile lyases.

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Intramolecular Direct Arylation and Heck Reactions in the Formation of Medium‐Sized Rings: Selective Synthesis of Fused Indolizine, Pyrroloazepine and Pyrroloazocine Systems
Authors: Coya Estibaliz , Sotomayor Nuria , Lete Esther
Published: April 2014

The intramolecular palladium‐catalyzed reaction of N‐(iodoarylalkyl)pyrroles can be applied for the selective synthesis of medium‐sized rings by choosing the appropriate catalytic systems to direct the reaction to the alkene or to the pyrrole nucleus. These reactions can also be extended to the corresponding heteroaryl halides. Thus, reaction conditions have been established to access selectively to (hetero)fused indolizine, pyrroloazepine and pyrroloazocine systems.

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Blepharo‐cheilo‐dontic (BCD) syndrome: Expanding the phenotype, case report and review of literature
Authors: Ababneh Farouq K. , Al‐Swaid Abdulrahman , Elhag Ahmed , Youssef Talaat , Alsaif Saif
Published: April 2014

The combination of lagophthalmia, euryblepharon, ectropion of lower eyelids, distichiasis, bilateral cleft lip and palate, and oligodontia comprises the blepharo‐cheilo‐dontic (BCD) syndrome. This combination has been found sporadically or with positive family history and inherited as an autosomal dominant condition with variable expression.

We described a Saudi boy with the cardinal signs consistent with the BCD syndrome. In addition to the common components of BCD syndrome that involve eyelids, lip, and teeth abnormalities, this patient is the third reported BCD case with imperforate anus, the second with thyroid agenesis, and the first with lumbosacral meningomyelocele. © 2014 Wiley Periodicals, Inc.
Orodental manifestations in ectodermal dysplasia—A review
Authors: Bergendal Birgitta
Published: April 2014

Oral signs and symptoms are present in most ectodermal dysplasias (EDs). The aim of this article is to summarize some of the literature on current knowledge of oral manifestations and orofacial function in EDs. The review will focus on the most common forms where dental manifestations can be crucial for a differential diagnosis of ED among individuals with hypodontia and oligodontia, and preferably where the investigations included persons who had a genetically verified diagnosis. Disturbances in tooth development are common and can appear as tooth agenesis, variations in size and shape of teeth, defects in the mineralized tissues, and problems in tooth eruption. Abnormalities in number, size, and shape of teeth, and reduced salivary secretion, present in isolated oligodontia as well as in hypohidrotic ED and incontinentia pigmenti. In some more rare EDs these symptoms appear in combination with clefts of lip and/or palate in some affected individuals. Leukokeratosis in the oral mucosa presents in 70% of genetically confirmed cases of pachyonychia congenita. Also, orofacial function is often affected in ED, due to malformations, an incomplete dentition, and low salivary secretion which can compromise chewing, swallowing, and speech. In conclusion, there is a clinical overlap in oral signs and symptoms between isolated oligodontia and the most common EDs. Studies with genetically confirmed diagnoses and larger cohorts, as well as multicenter collaboration and the establishing of international registries, would create a basis for refined diagnostics, where oral examinations should be an integrated part of clinical assessment. © 2014 Wiley Periodicals, Inc.
Comparison of electrosurgical plasma coagulation and potassium‐titanyl‐phosphate laser photocoagulation for treatment of hereditary hemorrhagic telangiectasia‐related epistaxis
Authors: Luk Lauren , Mace Jess C. , Bhandarkar Naveen D. , Sautter Nathan B.
Published: April 2014

Background

Potassium‐titanyl‐phosphate (KTP) laser photocoagulation is commonly used for treatment of hereditary hemorrhagic telangiectasia‐related epistaxis (HHT‐RE). Electrosurgical plasma coagulation (EPC), also known as coblation, has not been rigorously evaluated for HHT‐RE.

Methods

Patients seeking treatment for HHT‐RE between September 2010 and September 2012 were prospectively randomized (1:1) to KTP or EPC in a single blind prospective cohort study. Length of surgery and estimated blood loss (EBL) were recorded. Epistaxis severity scores (ESSs) and 10‐cm visual analogue scale (VAS) scores for HHT‐RE–related symptoms were administered at enrollment and at 3, 6, 12 months following surgery. Statistical analysis used Friedman's and Pearson's chi‐square tests.

Results

Eleven HHT patients were prospectively enrolled and followed. Six patients underwent EPC treatment while 5 underwent KTP. Three patients in the KTP subgroup and 2 patients in the EPC subgroup requested additional surgical treatment within 12 months (p > 0.999). There were no significant differences in terms of EBL (p = 0.126) and length of surgery (p = 0.429) between treatment groups. Mean ESSs were not significantly different between groups at any follow‐up point (KTP, p = 0.896; EPC, p = 0.159). Compared to KTP, mean ESSs were higher in the EPC subgroup at baseline and lower at all other time points. Mean nasal obstruction VAS scores were significantly lower in the EPC subgroup at all follow‐up points.

Conclusion

EPC is a viable alternative to KTP laser photocoagulation for epistaxis control in patients with HHT. Subjectively, patients experience less nasal obstruction following EPC as compared to KTP treatment. A multicentered, well‐powered study is warranted to better determine treatment outcomes.
Swing technique for middle turbinate preservation in expanded endonasal skull base approaches
Authors: Barham Henry P. , Gould Elizabeth A. , Ramakrishnan Vijay R.
Published: April 2014

Endoscopic endonasal approaches to the middle fossa and orbital apex have traditionally included resection of the middle turbinate to improve visualization and operating space. The aim of this publication is to demonstrate a surgical technique that affords similar visualization and space but preserves the middle turbinate. We describe a technical modification that allows for conservation of the middle turbinate and describe an illustrative case. As current surgical techniques evolve towards progressively less morbidity, preservation of anatomic structures such as the middle turbinate will be pursued. In the case described, middle turbinate preservation did not negatively affect access or visualization and did not appear to alter postoperative wound healing. With middle turbinate preservation, the principle function of airflow conditioning and potential neural regeneration are maintained.
Preoperative concerns of patients undergoing endoscopic sinus surgery
Authors: Yeung Jeffrey C. , Brandt Michael G. , Franklin Jason H. , Doyle Philip C. , Rotenberg Brian W. , Kilty Shaun J.
Published: April 2014

Background

Patient‐centered care is recognized as being fundamental to successful medical practice. The effectiveness of patient‐centered care has classically been measured by posttreatment outcomes, such as patient compliance and psychosocial responses. Systematic assessment of patient concerns prior to treatment has been limited, to date. Endoscopic sinus surgery (ESS) is an elective procedure for chronic rhinosinusitis that carries a clear, defined set of risks. The objective of this prospective observational study was to determine the concerns of patients undergoing ESS for chronic rhinosinusitis.

Methods

A total of 180 patients undergoing ESS for chronic rhinosinusitis with or without polyposis were recruited at 2 Canadian tertiary care centers. They completed a validated survey assessing their concerns regarding the risks and outcomes of surgery. Data was analyzed using descriptive statistics and analysis of variance.

Results

Patients had a low degree of concern prior to undergoing surgery (overall score 2.8/9), though individual variability existed. Subjects felt the greatest level of concern regarding potential need for revision surgery as well as the wait time for surgery. Patients were least concerned about psychological factors (mean = 1.8/9). No differences with respect to age or gender were identified. Mean scores for cerebrospinal fluid leak and orbital injury were 3 and 3.2, respectively.

Conclusion

Patients’ level of concern prior to undergoing elective surgery is generally low. Patients’ areas of greatest concern may not align with those perceived by the physician. This study provides insight into patient concerns prior to undergoing elective sinus surgery and emphasizes the importance of the patient‐centered approach to care.
Light‐Induced Ruthenium‐Catalyzed Nitrene Transfer Reactions: A Photochemical Approach towards N‐Acyl Sulfimides and Sulfoximines
Authors: Bizet Vincent , Buglioni Laura , Bolm Carsten
Published: April 2014

1,4,2‐Dioxazol‐5‐ones are five‐membered heterocycles known to decarboxylate under thermal or photochemical conditions, thus yielding N‐acyl nitrenes. Described herein is a light‐induced ruthenium‐catalyzed N‐acyl nitrene transfer to sulfides and sulfoxides by decarboxylation of 1,4,2‐dioxazol‐5‐ones at room temperature, thus providing direct access to N‐acyl sulfimides and sulfoximines under mild reaction conditions. In addition, a one‐pot sulfur imidation/oxidation sequence catalyzed by a single ruthenium complex is reported.
Intramolecular Aminocyanation of Alkenes by NCN Bond Cleavage
Authors: Pan Zhongda , Pound Sarah M. , Rondla Naveen R. , Douglas Christopher J.
Published: April 2014

A metal‐free, Lewis acid promoted intramolecular aminocyanation of alkenes was developed. B(C6F5)3 activates N‐sulfonyl cyanamides, thus leading to a formal cleavage of the NCN bonds in conjunction with vicinal addition of sulfonamide and nitrile groups across an alkene. This method enables atom‐economical access to indolines and tetrahydroquinolines in excellent yields, and provides a complementary strategy for regioselective alkene difunctionalizations with sulfonamide and nitrile groups. Labeling experiments with 13C suggest a fully intramolecular cyclization pattern due to the lack of label scrambling in double crossover experiments. Catalysis with Lewis acid is realized and the reaction can be conducted under air.
The Experimental Observation of the Intramolecular NO2/CO Interaction in Solution
Authors: Chiarucci Michel , Ciogli Alessia , Mancinelli Michele , Ranieri Silvia , Mazzanti Andrea
Published: April 2014

The weak electrostatic interaction between nitro and carbonyl moieties has been observed by means of variable‐temperature NMR spectroscopy. Its energetic contribution was evaluated to be about 3 kcal mol−1 by DFT calculations, and confirmed by the measurement of internal energy barriers to the rotation of suitable nitroaryl rings.
Stabilization of Catalytically Active Cu+ Surface Sites on Titanium–Copper Mixed‐Oxide Films
Authors: Baber Ashleigh E. , Yang Xiaofang , Kim Hyun You , Mudiyanselage Kumudu , Soldemo Markus , Weissenrieder Jonas , Senanayake Sanjaya D. , Al‐Mahboob Abdullah , Sadowski Jerzy T. , Evans Jaime , Rodriguez José A. , Liu Ping , Hoffmann Friedrich M. , Chen Jingguang G. , Stacchiola Darío J.
Published: April 2014

The oxidation of CO is the archetypal heterogeneous catalytic reaction and plays a central role in the advancement of fundamental studies, the control of automobile emissions, and industrial oxidation reactions. Copper‐based catalysts were the first catalysts that were reported to enable the oxidation of CO at room temperature, but a lack of stability at the elevated reaction temperatures that are used in automobile catalytic converters, in particular the loss of the most reactive Cu+ cations, leads to their deactivation. Using a combined experimental and theoretical approach, it is shown how the incorporation of titanium cations in a Cu2O film leads to the formation of a stable mixed‐metal oxide with a Cu+ terminated surface that is highly active for CO oxidation.
Deutliche Belege für Ein‐Elektronen‐Übertragungen in der Boryl‐Anionenchemie: Isolierung und Reaktivität eines neutralen Borolradikals
Authors: Bertermann Rüdiger , Braunschweig Holger , Dewhurst Rian D. , Hörl Christian , Kramer Thomas , Krummenacher Ivo
Published: April 2014

Zwar gelang Yamashita et al. schon 2006 die Synthese eines Borylanions, aber immer noch sind Bor‐zentrierte Nukleophile seltene und begehrte Syntheseziele. Eine Reihe entsprechender Borylanionen wurde seitdem erhalten, und von zweien ist bekannt, dass sie mit Methyliodid anscheinend nukleophile Substitutionsreaktionen eingehen. Eines davon, ein Borol‐basiertes Borolylanion, zeigt nun Ein‐Elektronen‐Übertragungen (single‐electron‐transfers, SETs) bei seinen Reaktionen mit Triorganyltetrelhalogeniden, was durch die Isolierung eines ersten neutralen Borol‐basierten Radikals belegt werden konnte. Das Radikal wurde über Elementaranalyse, Einkristall‐Röntgenstrukturanalyse und EPR‐Spektroskopie charakterisiert und trägt zum Verständnis Bor‐basierten nukleophilen Reaktionsverhaltens und der zur wachsenden Bedeutung von Borradikalen in der Synthese bei. Diese Radikalreaktivität wurde auch zur Synthese von Verbindungen mit seltenen B‐Sn‐ und B‐Pb‐Bindungen genutzt, wovon letztere die erste isolierte und strukturell charakterisierte Verbindung einer “Nicht‐Cluster”‐B‐Pb‐Bindung ist.
Synthesis of Cyclic Amine Boranes through Triazole‐Gold(I)‐Catalyzed Alkyne Hydroboration
Authors: Wang Qiaoyi , Motika Stephen E. , Akhmedov Novruz G. , Petersen Jeffrey L. , Shi Xiaodong
Published: April 2014

The first catalytic alkyne hydroboration of propargyl amine boranecarbonitriles is accomplished with triazole‐AuI complexes. While the typical [L‐Au]+ species decomposes within minutes upon addition of amine boranecarbonitriles, the triazole‐modified gold catalysts (TA‐Au) remained active, and allowed the synthesis of 1,2‐BN‐cyclopentenes in one step with good to excellent yields. With good substrate tolerability and mild reaction conditions (open‐flask), this new method provides an alternative route to reach the interesting cyclic amine borane with high efficiency.
Lithographic Deposition of Patterned Metal–Organic Framework Coatings Using a Photobase Generator
Authors: Keitz Benjamin K. , Yu Chung Jui , Long Jeffrey R. , Ameloot Rob
Published: April 2014

A photobase generator was used to induce metal–organic framework (MOF) nucleation upon UV irradiation. This method was further developed into a simple, one‐step method for depositing patterned MOF films. Furthermore, the ability of our method to coat a single substrate with MOF films having different chemical compositions is illustrated. The method is an important step towards integrating MOF deposition with existing lithographic techniques and the incorporation of these materials into sensors and other electronic devices.
Telluride Misfit Layer Compounds: [(PbTe)1.17]m(TiTe2)n
Authors: Moore Daniel B. , Beekman Matt , Disch Sabrina , Johnson David C.
Published: April 2014

Telluride misfit layer compounds are reported for the first time. These compounds were synthesized using a novel approach of structurally designing a precursor that would form the desired product upon low‐temperature annealing, which allows the synthesis of kinetically stable products that do not appear on the equilibrium phase diagram. Four new compounds of the [(PbTe)1.17]m(TiTe2)n family are reported, and their structures were examined by a variety of X‐ray diffraction techniques.
Preparation and characterization of isotactic polypropylene/high‐density polyethylene/carbon black conductive films with strain‐sensing behavior
Authors: Zheng Shaodi , Huang Shilin , Ren Danqi , Yang Wei , Liu Zhengying , Yang Mingbo
Published: April 2014

Novel conductive films with a unique strain (ε)‐sensing behavior and based on a blend of isotactic polypropylene (iPP), high‐density polyethylene (HDPE), and carbon black (CB) were fabricated by an extrusion casting method. The morphology and ε‐sensing behavior of the films were investigated. Scanning electron microscope images showed that the oriented lamellae with a growing direction perpendicular to the extrusion direction were obtained in the HDPE phase and were accompanied by a cocontinuous structure of the iPP phase and HDPE/CB phase. The conductive percolation threshold (mc) and resistivity–ε behavior of the thin films are affected by the drawing ratio during the process of film preparation. The mc and electrical resistance of the iPP/HDPE/CB composite films increased with the drawing ratio. The gauge factor of the films within the elastic region decreased with increasing drawing ratio. Furthermore, the result of iPP/(HDPE/CB) 40/60 with a high drawing ratio shows that a reversible conductivity was obtained during the cyclic tensile testing (ε = 10%), but an irreversible conductivity makes the film fail during use at the applied ε values of up to 15%. This makes them good piezoresistive candidates for ε‐sensing materials. Moreover, a simple structural model was proposed to describe the reversible and irreversible phenomena in the electrical resistance behavior of the iPP/HDPE/CB films under tensile loading. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40686.
Characterization and biocompatibility of chestnut shell fiber–based composites with polyester
Authors: Wu Chin‐San , Hsu Yi‐Chiang , Liao Hsin‐Tzu , Yen Fu‐San , Wang Chen‐Yu , Hsu Chia‐Tsc
Published: April 2014

The structural, mechanical, biocompatibility, and biodegradability properties of composite materials formed of poly(butylene succinate) (PBS) and natural fiber (chestnut shell fiber; CSF) were evaluated. Maleic anhydride‐grafted poly(butylene succinate) (PBS‐g‐MA) and treated (crosslinked) CSF (TCSF) were used to improve the mechanical properties of PBS/CSF composites. The results show that PBS‐g‐MA/TCSF composites have superior mechanical properties compared with both pure PBS and PBS/CSF composites, which is attributed to better compatibility between the polymer and TCSF. Normal human foreskin fibroblasts (FBs) were seeded onto these two series of composites to characterize the biocompatibility. FB proliferation, collagen production, and cytotoxicity assays on the PBS/CSF series of composites exhibited superior results compared with those on the PBS‐g‐MA/TCSF composites. PBS‐g‐MA/TCSF was found to be more water resistant than PBS/CSF, and the weight loss of both the composites buried in soil compost indicated that both were biodegradable, especially at high levels of CSF substitution. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40730.
Design of XNBR nanocomposites for underwater acoustic sensor applications: Effect of MWNT on dynamic mechanical properties and morphology
Authors: Sasikumar K. , Manoj N. R. , Mukundan T. , Khastgir D.
Published: April 2014

In this work, application of rubber‐MWNT nanocomposite for underwater acoustic sensors is explored. The nanocomposite is developed by incorporating multiwalled carbon nanotubes (MWNT) into carboxylated nitrile rubber by mechanical mixing. The addition of MWNT up to 10 phr is found to result in about 330% increase in tensile strength, 140% increase in modulus, and 160% increase in tear strength. Transmission electron microscopy and scanning electron microscopy analyses indicate uniform dispersion of nanotubes in the rubber matrix. Dynamic mechanical analysis shows that damping at ambient temperature gradually increases with increasing filler content. This is attributed to the augmented frictional energy loss at the interface. The damping peak position shifts upward with increase in MWNT concentration, which may be gainfully used to tune to the operational frequency range of underwater acoustic sensors. Payne effect is observed at higher filler concentration due to the breakage of aggregates formed by filler–filler interaction. The nanocomposite may find application for damping structural vibrations and thus to improve the performance of underwater acoustic sensors. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40752.
A study of wet and dry strength properties of unaged and hygrothermally aged paper sheets reinforced with biopolymer composites
Authors: Adel Abeer M. , Dupont Anne‐Laurence , Abou‐Yousef Hussein , El‐Gendy Ahmed , Paris Sabrina , El‐Shinnawy Nabila
Published: April 2014

Biopolymers and their composites were added during the formation of unbleached Kraft bagasse pulp paper sheets to improve the mechanical strength properties of the produced hand sheets. The biopolymers (cellulose, chitosan, and chitosan‐cellulose composite) were either crosslinked or noncrosslinked and they were added in series of concentrations from 0.1% to 1.5%. The characterization of the samples using the Fourier transform infrared (IR) technique identified differences in the intensities of the characteristic IR absorption bands for chitosan, cellulose, and their composites, these differences are due to the various degrees of hydrogen bonding. The surface morphology of the biopolymers composites and the treated paper sheets were studied using SEM technique. Both the equilibrium moisture sorption and the diffusion coefficient of the paper sheets containing 1% additives were evaluated at regular time intervals. The long‐term stability of the treated paper with biopolymers was verified by exposing the treated and the untreated sheets to hygrothermal ageing. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40761.
Interleukin‐21–Producing c‐Maf–Expressing CD4+ T Cells Induce Effector CD8+ T Cells and Enhance Autoimmune Inflammation in Scurfy Mice
Authors: Iwamoto Taro , Suto Akira , Tanaka Shigeru , Takatori Hiroaki , Suzuki Kotaro , Iwamoto Itsuo , Nakajima Hiroshi
Published: April 2014

Objective

FoxP3 induces Treg cells and prevents autoimmune diseases. However, the precise mechanisms of FoxP3 in the prevention of autoimmune diseases remain unknown. We undertook this study to determine the regulatory roles of FoxP3 in autoimmune inflammation by using FoxP3‐mutant sf mice.

Methods

We characterized interleukin‐21 (IL‐21)– producing cells in sf mice. We examined the underlying mechanisms of enhanced IL‐21 production in sf mouse CD4+ T cells. We examined the roles of IL‐21 and CD8+ T cells in autoimmune inflammation in sf mice using IL‐21 receptor (IL‐21R)–deficient sf mice.

Results

IL‐21–producing c‐Maf+CD4+ T cells, which were distinct from Th17 cells, were increased in sf mice. Increased c‐Maf expression was involved in enhanced IL‐21 production in sf mouse CD4+ T cells. Experiments using bone marrow chimeric mice showed that lack of cell‐extrinsic suppression by FoxP3+ Treg cells, but not cell‐intrinsic defects in FoxP3 in sf mouse CD4+ T cells, was mainly involved in the development of IL‐21–producing c‐Maf+CD4+ T cells in sf mice. IL‐21R deficiency prolonged survival and reduced multiorgan autoimmune inflammation in sf mice. Moreover, IL‐21R deficiency decreased short‐lived effector CD8+ T cells in the lung in sf mice. Furthermore, depletion of CD8+ T cells inhibited lung inflammation in sf mice, suggesting that CD8+ T cells are critical for inducing lung inflammation in sf mice.

Conclusion

Unique IL‐21–producing c‐Maf+ CD4+ T cells develop in the absence of FoxP3+ Treg cells, induce short‐lived effector CD8+ T cells, and enhance multiorgan autoimmune inflammation in sf mice.
Evidence of Abnormal Epidermal Nerve Fiber Density in Fibromyalgia: Clinical and Immunologic Implications
Authors: Caro Xavier J. , Winter Earl F.
Published: April 2014

Objective

A subset of patients with fibromyalgia (FM) exhibit a large fiber demyelinating peripheral polyneuropathy akin to that seen in chronic inflammatory demyelinating polyneuropathy (CIDP). It has been suggested that this demyelinating process is likely to be immune mediated. Because it is known that similar large fiber neuropathic lesions may be associated with a cutaneous small fiber neuropathy, we sought to determine the prevalence of small fiber neuropathy, as measured by epidermal nerve fiber density (ENFD), in a series of patients with FM and clinically healthy control subjects.

Methods

Forty‐one consecutive patients with FM and 47 control subjects underwent a 3‐mm punch skin biopsy at the proximal thigh and distal leg near the ankle, for analysis of the ENFD. Patients with FM who had clinical evidence of a disorder known to be associated with small fiber neuropathy were excluded. The patients with FM also underwent pinwheel testing and vibratory testing for hypesthesia and serologic testing for a series of cytokine, circulating immune complex, and complement measurements.

Results

All patients with FM had evidence of stocking hypesthesia. The ENFD of patients with FM was lower than that of control subjects at both the calf (mean ± SD 5.8 ± 2.8 versus 7.4 ± 1.9; P = 0.0002) and thigh (9.3 ± 3.2 versus 11.3 ± 2.0; P = 0.0007). There was an inverse correlation between calf ENFD and age at the time of skin biopsy in patients with FM (r = −0.29, P = 0.03) but not in control subjects; however, analysis of covariance showed that this relationship could not be explained by aging alone. Serologic evaluation showed an inverse correlation between calf ENFD in patients with FM and the interleukin‐2 receptor (IL‐2R) level (r = −0.28, P = 0.04). However, an inverse correlation between thigh ENFD and serum IL‐2R levels did not reach significance (P = 0.08). Analysis of thigh‐to‐calf ENFD ratios suggested that the ENFD decline in FM is affected by both a diffuse and a length‐dependent process.

Conclusion

The calf and thigh ENFD in patients with FM is significantly diminished compared with that in control subjects. Advancing age alone cannot explain this finding. Calf ENFD was inversely correlated, although weakly, with serum levels of IL‐2R. These findings suggest that small fiber neuropathy is likely to contribute to the pain symptoms of FM; that pain in this disorder arises, in part, from a peripheral immune‐mediated process; and that measurement of ENFD may be a useful clinical tool in FM.
A study on mental models of taggers and experts for article indexing based on analysis of keyword usage
Authors: Chen Ya‐Ning , Ke Hao‐Ren
Published: April 2014

This article explores the mental models of article indexing of taggers and experts in keyword usage. Better understanding of the mental models of taggers and experts and their usage gap may inspire better selection of appropriate keywords for organizing information resources. Using a data set of 3,972 tags fromCiteULike and 6,708 descriptors from Library and Information Science Abstracts (LISA) from 1,489 scholarly articles of 13 library and information science journals, social network analysis and frequent‐pattern tree methods were used to capture and build up the mental models of article indexing of taggers and experts when using keywords, and to generalize their structures and patterns. When measured with respect to the terms used, a power‐law distribution, a comparison of terms used as tags and descriptors, social network analysis (including centrality, overall structure, and role equivalent) and frequent‐pattern tree analysis, little similarity was found between the mental models of taggers and experts. Twenty‐five patterns of path‐based rules and 12 identical rules of frequent‐pattern trees were shared by taggers and experts. Title‐ and topic‐related keyword categories were the most popular keyword categories used in path‐based rules of frequent‐pattern trees, and also the most popular members of 25 patterns and the starting point of the 12 identical rules.
Controlled Crystallization of Cyano‐Bridged Cu–Pt Coordination Polymers with Two‐Dimensional Morphology
Authors: Zakaria Mohamed B. , Hu Ming , Tsujimoto Yoshihiro , Sakka Yoshio , Suzuki Norihiro , Kamachi Yuichiro , Imura Masataka , Ishihara Shinsuke , Ariga Katsuhiko , Yamauchi Yusuke
Published: April 2014

Two‐dimensional (2D) coordination polymers (CPs) have a highly accessible surface area that permits guest molecules to effectively access the micropores in the CPs. Here we report a bottom‐up synthesis of 2D cyano‐bridged Cu–Pt CP nanoflakes using trisodium citrate as a chelating agent, which controls the nucleation rate and the crystal growth. The lateral sizes of the CP nanoflakes are controlled by changing the amount of trisodium citrate used. We strongly believe that our method will be useful for the preparation of other types of 2D CP nanoflakes. The 2D CPs have many active sites for catalytic and electrochemical reactions, and furthermore the assembled CPs can be used as membrane filters.
Preparation and evaluation of the effect of Fe3O4@piroctone olamine magnetic nanoparticles on matrix metalloproteinase‐2: A preliminary in vitro study
Authors: Shakibaie Mojtaba , Haghiri Mahboobe , Jafari Mandana , Amirpour‐Rostami Sahar , Ameri Alieh , Forootanfar Hamid , Mehrabani Mitra
Published: April 2014

In the present study, Fe3O4 magnetic nanoparticles were synthesized by the coprecipitation of Fe2+ and Fe3+ ions and used as a nanocarrier for the production of piroctone‐olamine‐loaded Fe3O4 nanoparticles (Fe3O4@PO NPs). The nanocrystalline structure of the prepared iron oxide species was confirmed by the X‐ray diffraction spectroscopy method. Particle size distribution analysis showed that the size of Fe3O4@PO NPs was in the range of 5–55 nm. The magnetization curve of Fe3O4@PO NPs (with saturation magnetization of 28.2 emu/g) confirmed its ferromagnetic property. Loading of PO on the surface of Fe3O4 NPs qualitatively verified by Fourier transform infrared spectrum obtained from Fe3O4@PO NPs. Cytotoxicity studies on the human fibrosarcoma cell line (HT‐1080) revealed higher inhibitory effect of Fe3O4@PO NPs (50% cell death [IC50] of 8.1 µg/mL) as compared with Fe3O4 NPs (IC50 of 117.1 µg/mL) and PO (IC50 of 71.2 µg/mL) alone. In the case of human normal fibroblast (Hs68), the viability percentage was found to be 75% in the presence of Fe3O4@PO NPs (120 µg/mL). Gelatin zymography showed 17.2% and 34.6% inhibition of matrix metalloproteinase‐2 (MMP‐2) in the presence of Fe3O4@PO and PO, respectively, at the same concentration of 40 µg/mL, whereas Fe3O4 NPs did not inhibit MMP‐2 at any concentration.
Life cycle greenhouse gas emissions of electricity generation from corn cobs in Ontario, Canada
Authors: Sanscartier David , Dias Goretty , Deen Bill , Dadfar Humaira , McDonald Ian , MacLean Heather L.
Published: April 2014

Policy initiatives have motivated a search for environmentally sustainable alternatives to fossil‐fuel‐based electricity generation. Agricultural residues such as corn cobs may be a suitable feedstock. A life cycle approach was used to estimate the greenhouse gas (GHG) emission impacts associated with the use of pellets produced from corn cobs as the sole fuel for the generation of electricity at a hypothetically retrofitted coal‐fired generating station in Ontario, Canada. Pellets are compared with current coal and hypothetical natural gas combined cycle (NGCC) facilities. A life cycle model and soil carbon model calibrated for the agricultural region of interest were combined to quantify the GHG emissions of the biomass product system. The corn cob product system's life cycle emissions (240 g CO2eq kWh−1) are 40% and 80% lower than those of the NGCC and coal product systems, respectively. If corn cobs are left in the field to decompose, some carbon is sequestered in the soil, thus their removal from the field and combustion at the generation station represents a net GHG emission, accounting for 60% of life cycle emissions. In addition to the GHG impacts of combustion, removing agricultural residues from fields may reduce soil health, increase erosion and affect soil fertility through loss of soil organic carbon and nutrients. Their sustainable use should therefore consider the maintenance of soil fertility over the long‐term. Nevertheless, the use of the feedstock in place of coal may provide substantial GHG emissions mitigation.