bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrodeposition of a Mn–Cu–ZnO Hybrid Material for Supercapacitors: A Soft X‐ray Fluorescence and Absorption Microspectroscopy Study
Authors: Bozzini Benedetto , Gianoncelli Alessandra , Mele Claudio , Sgura Ivonne , Kiskinova Maya
Published: November 2013

Synchrotron‐based soft‐X‐ray imaging and microspectroscopy with sub‐micrometer spatial resolution are used to investigate the electrodeposition of Mn–Cu–ZnO, a prospective active material for supercapacitors. This study is focused on the correlation of the local current density and the spatial distribution of the composition and chemical‐state in electrodeposits grown potentiostatically at −0.7 V (vs a saturated calomel electrode), as well as the optimal potential for the achievement of high specific capacitance and cycling stability. The morphology, elemental distribution, and the local chemical state of both the electrode deposits and the grown dendrite structures are followed by using X‐ray imaging, X‐ray fluorescence mapping, and X‐ray absorption microspectroscopy. For transmission soft‐X‐ray measurements, a thin‐layer Hull‐type microcell is developed and fabricated by using electron‐beam lithography. The information obtained for the spatial distribution of the deposit is complemented by using electrochemical measurements and numerical simulations.
Bis(tert‐butylpyrene) Nanotweezers and Nanocalipers: Enhanced Extraction and Recognition Abilities for Single‐Walled Carbon Nanotubes
Authors: Liu Gang , Rahman A. F. M. Mustafizur , Chaunchaiyakul Songpol , Kimura Takahide , Kuwahara Yuji , Komatsu Naoki
Published: November 2013

We developed a host–guest methodology for separation of single‐walled carbon nanotubes (SWNTs) according to the handedness, diameter and metallicity by the use of diporphyrin nanotweezers and nanocalipers. Although the pyrene has been frequently used to replace porphyrin, due to a similar affinity to the surface of SWNTs and better availability, the extraction and recognition abilities of dipyrene nanotweezers were not so good as those of diporphyrin ones as we reported previously. However, introduction of a tert‐butyl substituent at the 7′‐position of 2‐pyrene is found to enhance the extraction and recognition abilities of dipyrene nanotweezers and nanocalipers. That is, (6,5)‐SWNTs were obtained in high purity by use of bis(tert‐butylpyrene) nanotweezers with a phenanthrene spacer and metallic SWNTs were highly enriched by use of bis(tert‐butylpyrene) nanocalipers with a carbazole–anthracene–carbazole spacer.
Ultrafast Deactivation Mechanism of the Excited Singlet in the Light‐Induced Spin Crossover of [Fe(2,2′‐bipyridine)3]2+
Authors: Sousa Carmen , de Graaf Coen , Rudavskyi Andrii , Broer Ria , Tatchen Jörg , Etinski Mihajlo , Marian Christel M.
Published: November 2013

The mechanism of the light‐induced spin crossover of the [Fe(bpy)3]2+ complex (bpy=2,2′‐bipyridine) has been studied by combining accurate electronic‐structure calculations and time‐dependent approaches to calculate intersystem‐crossing rates. We investigate how the initially excited metal‐to‐ligand charge transfer (MLCT) singlet state deactivates to the final metastable high‐spin state. Although ultrafast X‐ray free‐electron spectroscopy has established that the total timescale of this process is on the order of a few tenths of a picosecond, the details of the mechanisms still remain unclear. We determine all the intermediate electronic states along the pathway from low spin to high spin and give estimates for the deactivation times of the different stages. The calculations result in a total deactivation time on the same order of magnitude as the experimentally determined rate and indicate that the complex can reach the final high‐spin state by means of different deactivation channels. The optically populated excited singlet state rapidly decays to a triplet state with an Fe d6() configuration either directly or by means of a triplet MLCT state. This triplet ligand‐field state could in principle decay directly to the final quintet state, but a much faster channel is provided by internal conversion to a lower‐lying triplet state and subsequent intersystem crossing to the high‐spin state. The deactivation rate to the low‐spin ground state is much smaller, which is in line with the large quantum yield reported for the process.
Luminescence Color‐Tuning through Polymorph Doping: Preparation of a White‐Emitting Solid from a Single Gold(I)–Isocyanide Complex by Simple Precipitation
Authors: Seki Tomohiro , Kurenuma Sayaka , Ito Hajime
Published: November 2013

We report the luminescent color tuning of a new complex, 2‐benzothiophenyl(4‐methoxyphenyl isocyanide)gold(I) (1), by using a new “polymorph doping” approach. The slow crystallization of the complex 1 afforded three different pure polymorphic crystals with blue, green, and orange emission under UV‐light irradiation. The crystal structures of pure polymorphs of 1 were investigated in detail by means of single‐crystal X‐ray analyses. Theoretical calculations based on the single‐crystal structures provided qualitative explanation of the difference in the excited energy‐levels of the three polymorphs of 1. In sharp contrast, the rapid precipitation of 1, with the optimized conditions reproducibly afforded homogeneous powder materials showing solid‐state white‐emission with Commission Internationale de l’Éclairage (CIE) 1931 chromaticity coordinates of (0.33, 0.35), which is similar to pure white. New “polymorphic doping” has been revealed to be critical to this white emission through spectroscopic and X‐ray diffraction analyses. The coexistence of the multiple polymorphs of 1 within the homogeneous powder materials and the ideal mixing of multiple luminescent colors gave its white emission accompanied with energy transfer from the predominant green‐emitting polymorph to the minor orange‐emitting polymorph.
Diastereoselective Osmium‐catalyzed Vicinal Oxyamination of Acyclic Allylic Alcohol Derivatives
Authors: Masruri  , Kanizaj Nicholas , McLeod Malcolm D.
Published: November 2013

The osmium‐catalyzed oxyamination of chiral acyclic allylic alcohol derivatives bearing mono‐ and 1,1‐di‐substituted double bonds with benzyl N‐(4‐tosyloxy)carbamate proceeds with high regioselectivity and moderate levels of diastereoselectivity favoring the anti product. The observed stereoselectivity shows a clear and systematic trend with anti:syn ratios increasing in line with the size of substituent at both the allylic stereocenter and double bond α‐carbon. The stereoinduction is in accord with the sense of diastereoselectivity predicted by Kishi's empirical rule and a previously reported transition state model for the osmium‐catalyzed dihydroxylation of allylic alcohol derivatives. In contrast, allylic alcohol derivatives bearing trisubstituted double bonds show low or no reactivity in the oxyamination reaction affording the syn product in low yield in the cases examined. Chirality 26:724–733, 2013. © 2013 Wiley Periodicals, Inc.
Hedgehog Pathway Agonism: Therapeutic Potential and Small‐Molecule Development
Authors: Hadden M. Kyle
Published: November 2013

The Hedgehog (Hh) pathway is a developmental signaling pathway that plays multiple roles during embryonic development and in adult tissues. Constitutive Hh signaling has been linked to the development and progression of several forms of cancer, and the application of small‐molecule pathway inhibitors as anticancer chemotherapeutics is well studied and clearly defined. Activation of the Hh pathway as a therapeutic strategy for a variety of degenerative or ischemic disorders has also been proposed; however, the development of small‐molecule Hh agonists has received less attention. The goal of this review is to highlight the recent evidence supporting the therapeutic potential of Hh pathway activators and to provide a comprehensive overview of small‐molecule pathway agonists.
Nanostructures from Self‐Assembling Triazine Tertiary Amine N‐Oxide Amphiphiles
Authors: Beecham Matthew P. , Clarkson Guy J. , Hall Gareth , Marsh Andrew
Published: November 2013

A new set of amphiphilic tertiary amine N‐oxides has been prepared and their self‐assembly properties observed in aqueous solution by tensiometry, dynamic and static light scattering. X‐ray crystallographic analysis of parent amines and sulfoxide congeners indicates the formation of hydrogen‐bonded dimers as the primary assembly unit for formation of vesicles in preference to the compact micelles typical of lauryl dimethylamine N‐oxide (LDAO). 6‐Benzyloxy‐N,N′‐bis(5‐diethylaminopentylamine oxide)[1,3,5]triazine‐2,4‐diamine forms a 1 μm vesicle observed to entrap fluorescein. The [1,3,5]triazine core thus allows variation of the new self‐assembled structures from nano‐ to micrometre length scales.
ZnII–Dipyridylamide‐Based Coordination Frameworks: Structural Transformation and Anion Effect
Authors: Tzeng Biing‐Chiau , Yeh Chien‐Ting , Chang Tsung‐Yi
Published: November 2013

We have synthesized a series of 1 D double‐zigzag ({[Zn(paps)2(H2O)2](PF6)2}n (1), {[Zn(papo)2(H2O)2](PF6)2}n (3), and {[Zn(papc)2(H2O)2](PF6)2}n (5)) and 2 D polyrotaxane ([Zn(papc)2(PF6)2]n (6)) frameworks through the reaction of Zn(PF6)2 with dipyridylamide ligands (N,N′‐bis(pyridylcarbonyl)‐4,4′‐diaminodiphenyl thioether (paps), N,N′‐bis(pyridylcarbonyl)‐4,4′‐diaminodiphenyl ether (papo), and N,N′‐(methylenedi‐p‐phenylene)bispyridine‐4‐carboxamide (papc), respectively), and their molecular structures have been determined through X‐ray diffraction studies. From the powder X‐ray diffraction (PXRD) experiments, it is found that on heating, the double‐zigzag frameworks 1 and 3 undergo structural transformation to give the respective polyrotaxane frameworks 2 ([Zn(paps)2(PF6)2]n) and 4 ([Zn(papo)2(PF6)2]n), which matched well with those of their Zn(ClO4)2 analogues. Furthermore, grinding the solid samples of 2 and 4 in the presence of moisture resulted in total conversion back to the double‐zigzag frameworks 1 and 3, respectively. Although the 1 D double‐zigzag and 2 D polyrotaxane frameworks of ZnII‐paps and ‐papo with ClO4− anions can be also interconverted through heating and grinding in the presence of moisture, the related ZnII‐papc framework with ClO4− can only undergo a structural transformation process through heating. Surprisingly, reversible structural transformation between 5 and 6 has been proven successfully. In this work, we show that by replacing ClO4− with PF6−, a series of ZnII‐papx‐based frameworks can be obtained. Significantly, this indicates that a remarkable anion effect on such a novel structural transformation process has been demonstrated.
Direct Reduction of Carbon Dioxide to Formate in High‐Gas‐Capacity Ionic Liquids at Post‐Transition‐Metal Electrodes
Authors: Watkins John D. , Bocarsly Andrew B.
Published: November 2013

As an approach to combat the increasing emissions of carbon dioxide in the last 50 years, the sequestration of carbon dioxide gas in ionic liquids has become an attractive research area. Ionic liquids can be made that possess incredibly high molar absorption and specificity characteristics for carbon dioxide. Their high carbon dioxide solubility and specificity combined with their high inherent electrical conductivity also creates an ideal medium for the electrochemical reduction of carbon dioxide. Herein, a lesser studied ionic liquid, 1‐ethyl‐3‐methylimidazolium trifluoroacetate, was used as both an effective carbon dioxide capture material and subsequently as an electrochemical matrix with water for the direct reduction of carbon dioxide into formate at indium, tin, and lead electrodes in good yield (ca. 3 mg h−1 cm−2).
Hydropnictination Reactions of Carbodiimides and Isocyanates with Protonated Heptaphosphide and Heptaarsenide Zintl Ions
Authors: Turbervill Robert S. P. , Goicoechea Jose M.
Published: November 2013

By following a similar procedure to that employed for the synthesis of [HP7]2–(1), the synthesis and characterization of the hydrogenheptaarsenide dianion [HAs7]2–(2) was achieved. Building on previous research that has shown that [HP7]2–can react with carbodiimides to yield amidine‐functionalized cluster anions [P7C(NHR)(NR)]2–, we have found that the analogous hydroarsination reactions are also possible by reaction of2with RC=N=CR to yield [As7C(NHR)(NR)]2–[R = Dipp (3),iPr (4) and Cy (5); Dipp = 2,6‐diisopropylphenyl]. Furthermore, we also demonstrate that such hydropnictination reactions can be extended to other heteroallenes such as isocyanates (O=C=NAd; Ad = adamantyl) to afford the amide‐derivatized cluster anions [E7C(CO)(NHAd)]2–[E = P (6) and As (7)]. All new compounds were characterized by multinuclear NMR spectroscopy, elemental analyses and electrospray mass spectrometry. Clusters2,4,6and7were also characterized by single‐crystal X‐ray diffraction of [K(18‐crown‐6)]2[2], [K(18‐crown‐6)]2[4], [K(18‐crown‐6)]2[6]·py (py = pyridine) and [K(18‐crown‐6)]2[7]·py. Crystal structures confirming composition and connectivity were also obtained for anions3and5.
Adsorptive capacity of polyacrylonitrile modified with triethylenetetramine for removal of copper and cadmium ions from aqueous solutions
Authors: Soltanzadeh Mehdi , Kiani Gholamreza , Khataee Alireza
Published: November 2013

A simple method was developed for modification of polyacrylonitrile with triethylenetetramine (PAN‐TETA) as absorbent of copper and cadmium ions. PAN‐TETA and its metal complexes were characterized by FT‐IR and SEM. FT‐IR studies confirmed the presence of metal ions in the metal‐PAN‐TETA complexes. The obtained aminated polyacrylonitrile was evaluated for chelating of Cu(II) and Cd(II) ions. Batch adsorption studies were carried out on the effect of experimental parameters including pH, amount of adsorbent, contact time, initial concentration of metal ions, and temperature. Adsorption efficiency increased with increasing metal ions concentration, initial pH, and temperature. The adsorption kinetics followed pseudo‐second‐order kinetic model with correlation coefficients of 0.999. Experimental data were analyzed by model equations such as Langmuir and Freundlich isotherms. It was found that Langmuir isotherm model was better fitted with the adsorption data. The maximum sorption capacity of 109.26 and 99.67 mg g−1 for copper and cadmium ions were achieved in pH = 6, respectively. The negative value of ΔGº indicated the spontaneous nature of the adsorption. The competitive tests verified that PAN‐TETA had good adsorption selectivity for Cu (II) with the coexistence of copper and cadmium ions. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 1139–1147, 2014
Outcome in squamous cell carcinoma of the nasal vestibule: A single center experience
Authors: Vital Domenic , Morand Grégoire , Huber Gerhard F. , Studer Gabriela , Holzmann David
Published: November 2013

Background

The purpose of this study was to analyze the outcome of squamous cell carcinomas (SCCs) of the nasal vestibule and to identify factors predicting recurrence.

Methods

All patients treated between 1995 and 2012 were included in this study. Outcome was analyzed with respect to modality of therapy, age, sex, tobacco consumption, staging, surgical margins, and histological differentiation pattern.

Results

Thirty patients were included. Fourteen patients (47%) were found with T4, 1 patient (3%) with T3, 7 patients (23%) with T2, and 8 patients (27%) with T1 disease. Twenty‐one patients (70%) were treated surgically. Six patients (29%) needed postoperative radiation because of insufficient surgical margins. Radiation was the first‐line treatment in 9 patients (30%). Surgically treated patients with surgical margins <3 mm had significantly more locoregional recurrence compared to those with sufficient resections.

Conclusion

Advanced T4 carcinomas show a high recurrence rate. Insufficient surgical margins are the main predictor for a locoregional recurrence and should be avoided. © 2014 Wiley Periodicals, Inc. Head Neck 37: 46–51, 2015
Sensorineural hearing loss in patients with head and neck cancer after chemoradiotherapy and radiotherapy: A systematic review of the literature
Authors: Theunissen Eleonoor A. R. , Bosma Sophie C. J. , Zuur Charlotte L. , Spijker René , van der Baan Sieberen , Dreschler Wouter A. , de Boer Jan Paul , Balm Alfons J. M. , Rasch Coen R. N.
Published: November 2013

Background

Both radiotherapy (RT) and cisplatin‐based chemoradiotherapy (CRT) in patients with head and neck cancer may cause sensorineural hearing loss (SNHL). The purpose of this review was to provide more insight into SNHL because of CRT compared to RT.

Methods

Comprehensive search of Medline and Embase with the terms “radiotherapy” combined with “ototoxicity,” “head and neck squamous cell carcinoma,” and synonyms.

Results

Of the 2507 studies found, 21 were included in this study. Pooled analysis could not be committed because of heterogeneity. Incidence rates of SNHL after RT and CRT varied considerably, with percentages ranging from 0% to 43% and 17% to 88%, respectively. Factors that influenced the risk of SNHL were radiation dose to the cochlea, follow‐up time, age, baseline hearing level, and cisplatin dose.

Conclusion

The wide range of SNHL incidence rates makes it impossible to draw any conclusions on the severity of RT‐ and CRT‐induced ototoxicity. To allow for future comparison of study outcomes, development of uniform criteria is of utmost importance. © 2014 Wiley Periodicals, Inc. Head Neck 37: 281‐292, 2015
Spending by primary care practices—does it show what we expect?
Authors: James Marilyn , Stokes Elizabeth
Published: November 2013

Background

Over recent years, a number of policies and financial incentives in primary care have been proposed to tackle issues such as deprivation and health outcomes. This article investigates the association between healthcare spending, deprivation and outcomes. It argues that individual practice data are analysed before blanket application and acceptance that one size fits all in a local area.

Methods

Financial data were analysed alongside key outcome data, including quality and outcomes framework (QOF) indicators for a large urban primary care trust (PCT) in the UK. The PCT had a large population and number of practices, including single‐handed practices and an average list size in excess of 5000. The PCT will remain anonymous.

Results

There was no relationship between primary care investment and the practices' deprivation score. There was a strong statistically significant negative correlation between QOF payments and deprivation, (correlation = −0.46, p < 0.001). There were only weak links between primary care investment and health outcomes. There was no relationship between high emergency spending and health outcome.

Conclusions

The data presented suggest that one size does not necessarily fit all—in terms of providing the appropriate incentives in primary care, nor do national incentives and policies always have the desired effect. © 2013 The Authors. International Journal of Health Planning and Management published by John Wiley & Sons, Ltd.
Implementation of Community Health Fund in Tanzania: why do some districts perform better than others?
Authors: Maluka Stephen Oswald , Bukagile Godfrey
Published: November 2013

In early 1990s, Tanzania, like other African countries, introduced user fees in public health systems. Although user fees were considered important in promoting health, they appear to reduce people's access to health services. To counteract the detrimental effects of the user fees, various types of health insurances were introduced, including the Community Health Fund (CHF). Drawing from the review of minutes, health facility visits and key informant interviews, this study explored why implementation of the CHF in Tanzania has been more successful in some districts than in others.

The findings indicate that in Lindi district, the enrolment rate for the CHF was very low. This was attributed to high premium rates, frequent drug stock‐out, lack of trust by the community members to the health providers, low incentives and local politics. In contrast, in Iramba district, the performance was better. Availability of drugs in the health facilities, effective supervision, commitment of the top district‐level officials and incentives to the health facility committees were the main factors that facilitated good performance of the fund in Iramba district.

The focus of the implementation needs to be placed on the active engagement of the local‐level leaders and politicians who are responsible for the implementation of the policy. Equally important is the availability of quality health services in the health facilities. Copyright © 2013 John Wiley & Sons, Ltd.
A bispecific transmembrane antibody simultaneously targeting intra‐ and extracellular epitopes of the epidermal growth factor receptor inhibits receptor activation and tumor cell growth
Authors: Müller Nina , Hartmann Cord , Genßler Sabrina , Koch Joachim , Kinner Andrea , Grez Manuel , Wels Winfried S.
Published: November 2013

Epidermal growth factor receptor (EGFR) plays an important role in essential cellular processes such as proliferation, survival and migration. Aberrant activation of EGFR is frequently found in human cancers of various origins and has been implicated in cancer pathogenesis. The therapeutic antibody cetuximab (Erbitux) inhibits tumor growth by binding to the extracellular domain of EGFR, thereby preventing ligand binding and receptor activation. This activity is shared by the single chain antibody fragment scFv(225) that contains the same antigen binding domain. The unrelated EGFR‐specific antibody fragment scFv(30) binds to the intracellular domain of the receptor and retains antigen binding upon expression as an intrabody in the reducing environment of the cytosol. Here, we used scFv(225) and scFv(30) domains to generate a novel type of bispecific transmembrane antibody termed 225.TM.30, that simultaneously targets intra‐ and extracellular EGFR epitopes. Bispecific 225.TM.30 and related membrane‐anchored monospecific 225.TM and TM.30 proteins carrying extracellular scFv(225) or intracellular scFv(30) antibody fragments linked to a transmembrane domain were expressed in EGFR‐overexpressing tumor cells using a doxycycline‐inducible retroviral system. Induced expression of 225.TM.30 and 225.TM, but not TM.30 reduced EGFR surface levels and ligand‐induced EGFR activation, while all three molecules markedly inhibited tumor cell growth. Co‐localization of 225.TM with EGFR was predominantly found on the cell surface, while interaction with 225.TM.30 and TM.30 proteins resulted in the redistribution of EGFR to perinuclear compartments. Our data demonstrate functionality of this novel type of membrane‐anchored intrabodies in tumor cells and suggest distinct modes of action of mono‐ and bispecific variants.
The changes of gap junctions between pituitary folliculo‐stellate cells during the postnatal development of zucker fatty and lean rats
Authors: Sakuma Eisuke , Wada Ikuo , Soji Tsuyoshi , Wakabayashi Kenjiro , Otsuka Takanobu , Herbert Damon C.
Published: November 2013

We investigated the effect of leptin on the postnatal development of gap junctions between folliculo‐stellate cells by using Zucker fatty (fa/fa) rats that have defects of the functional leptin receptor. Male Zucker fatty rats (fa/fa) and male Zucker lean rats (+/+) were used at each of the following postnatal ages: 20, 30, 40, 50, 60, 70, 80, 90 days, and 1 year. On one of the aforementioned dates, the anterior pituitary glands were prepared for observation by transmission electron microscopy. We quantified the number of follicles and gap junctions, and calculated the rate of occurrence as the ratio of the number of gap junctions existing between folliculo‐stellate cells per intersected follicular profile. In Zucker lean male rats, the number of gap junctions remained relatively constant from days 50 to 90 (0.44 ± 0.02 to 0.49 ± 0.03), and was similar in 1 year old rats (0.47 ± 0.03). These data were statistically higher compared to Zucker fatty male rats. In Zucker fatty male rats, very few gap junctions were observed in 30‐day‐old rats (0.04 ± 0.01: mean ± SE). This disruption of gap junction formation persisted, and the number of gap junctions remained constant and showed a low level from days 40 to 90 (0.11 ± 0.02 to 0.17 ± 0.02); this finding was similar in 1‐year‐old rats (0.17 ± 0.02). These observations indicate that the effect of leptin over the gap junction formation within the anterior pituitary glands was directly mediated by interaction with the functional leptin receptor present on the folliculo‐stellate cells. Microsc. Res. Tech. 77:31–36, 2014. © 2013 Wiley Periodicals, Inc.
Evaluation of liver fibrosis and hepatic venous pressure gradient with MR elastography in a novel swine model of cirrhosis
Authors: Huang Steven Y. , Abdelsalam Mohamed E. , Harmoush Samer , Ensor Joe E. , Chetta Justin A. , Hwang Ken-Pin , Stafford R. Jason , Madoff David C. , Avritscher Rony
Published: November 2013

Purpose

To assess the correlation among MR elastography (MRE) measured liver stiffness (LS), liver fibrosis, and hepatic venous pressure gradient (HVPG) in a swine model of cirrhosis.

Materials and Methods

Three swine served as controls, and liver fibrosis was induced in eight swine by transarterial embolization. LS and HVPG were obtained at baseline and 4 weeks (prenecropsy) following induction of liver fibrosis.

Results

Four weeks following the induction of liver cirrhosis, experimental animals developed an increase in HVPG of 8.0 ± 6.4 mmHg compared with 0.3 ± 1.2 mmHg for controls (P = 0.08). Over the same timeframe, mean MRE‐measured LS increased 0.82 ± 0.39 kPa for experimental swine and 0.1 ± 0.05 kPa for controls (P = 0.01). A positive correlation was observed between increases in HVPG and LS (ρ = 0.682; P = 0.02). Liver fibrosis was measured on explanted livers at 4 weeks and yielded mean fibrosis scores of 2.8 for experimental animals and 0 for controls (P = 0.0016). A positive correlation was observed between higher LS and liver fibrosis (ρ = 0.884; P = 0.0003).

Conclusion

MRE is a reliable noninvasive technique to measure LS in a swine model of cirrhosis. Significant positive correlations were observed between LS and HVPG as well as LS and fibrosis. J. Magn. Reson. Imaging 2014;39:590–597. © 2013 Wiley Periodicals, Inc.
Distinguishing authentic and counterfeit banknotes by surface chemical composition determined using electrospray laser desorption ionization mass spectrometry
Authors: Kao Yi‐Ying , Cheng Chu‐Nian , Cheng Sy‐Chyi , Ho Hsiu‐O , Shiea Jentaie
Published: November 2013

Electrospray laser desorption ionization mass spectrometry (ELDI/MS) was used to rapidly distinguish authentic banknotes from counterfeits of the US dollar and the New Taiwan dollar. The banknotes' surfaces were irradiated with a pulsed ultraviolet laser, after which the desorbed ink compounds entered an electrospray plume and formed ions via interactions with charged solvent species. Authentic banknotes were found to differ from their counterfeit equivalents in their surface chemical compositions. The detected chemical compounds included various polymers, plasticizers and inks; these results were comparable with those obtained using solvent extraction followed by electrospray ionization mass spectrometry analysis. Because of the high spatial resolution of the laser beam, ELDI/MS analysis resulted in minimal damage to the banknotes. Copyright © 2013 John Wiley & Sons, Ltd.
Z‐sinapinic acid: the change of the stereochemistry of cinnamic acids as rational synthesis of a new matrix for carbohydrate MALDI‐MS analysis
Authors: Salum María L. , Itovich Lucia M. , Erra‐Balsells Rosa
Published: November 2013

Successful application of matrix‐assisted laser desorption/ionization (MALDI) MS started with the introduction of efficient matrices such as cinnamic acid derivatives (i.e. 3,5‐dimethoxy‐4‐hydroxycinnamic acid, SA; α‐cyano‐4‐hydroxycinnamic acid). Since the empirical founding of these matrices, other commercial available cinnamic acids with different nature and location of substituents at benzene ring were attempted. Rational design and synthesis of new cinnamic acids have been recently described too. Because the presence of a rigid double bond in its molecule structure, cinnamic acids can exist as two different geometric isomers, the E‐form and Z‐form. Commercial available cinnamic acids currently used as matrices are the geometric isomers trans or E (E‐cinnamic and trans‐cinnamic acids). As a new rational design of MALDI matrices, Z‐cinnamic acids were synthesized, and their properties as matrices were studied. Their performance was compared with that of the corresponding E‐isomer and classical crystalline matrices (3,5‐dihydroxybenzoic acid; norharmane) in the analysis of neutral/sulfated carbohydrates. Herein, we demonstrate the outstanding performance for Z‐SA. Sulfated oligosaccharides were detected in negative ion mode, and the dissociation of sulfate groups was almost suppressed. Additionally, to better understand the quite different performance of each geometric isomer as matrix, the physical and morphological properties as well as the photochemical stability in solid state were studied. The influence of the E/Z photoisomerization of the matrix during MALDI was evaluated. Finally, molecular modeling (density functional theory study) of the optimized geometry and stereochemistry of E‐cinnamic and Z‐cinnamic acids revealed some factors governing the analyte–matrix interaction. Copyright © 2013 John Wiley & Sons, Ltd.
An improved sample preparation method for the sensitive detection of peptides by MALDI‐MS
Authors: Hioki Yusaku , Kuyama Hiroki , Hamana Chikako , Takeyama Kohei , Tanaka Koichi
Published: November 2013

We describe here an optimization study of the sample preparation conditions for sensitive detection of peptides by matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS). Among many factors in the conditions, we varied the percent acetonitrile in the peptide solution, the percent acetonitrile in the matrix solution and the α‐cyano‐4‐hydroxycinnamic acid (CHCA) concentration in the matrix solution. CHCA was chosen because it is the most frequently used matrix for analyzing peptides. The well‐established dried‐droplet method was employed for sample deposition. The examined range of the concentration of CHCA was from 0.01 to 10 mg/ml, and the MeCN content of the solvent for matrix/analyte was 10% to 50%. The indicator for the detection sensitivity was the S/N ratio of the peaks of peptides used. Highly increased sensitivity (100‐ to 1000‐fold) was observed for the optimal CHCA concentration of 0.1 mg/ml in 20% MeCN/0.1% aq. trifluoroacetic acid (TFA), as compared with the conventional concentration (10 mg/ml) in 50% MeCN/0.1% aq. TFA. For example, the limit of detection of human ACTH 18–39 was 10 amol/well for the optimal condition but 10 fmol/well for the conventional condition. The optimal condition (0.1 mg/ml CHCA in 20% MeCN/0.1% aq. TFA) was verified with five model peptides and provided significant improvement in sensitivity (by two to three orders of magnitude) compared with the conventional conditions. Optimizing the CHCA concentration and solvent composition significantly improved the detection sensitivity in the analysis of peptides by MALDI‐MS. Copyright © 2013 John Wiley & Sons, Ltd.
LC/MS study of the UV filter hexyl 2‐[4‐(diethylamino)‐2‐hydroxybenzoyl]‐benzoate (DHHB) aquatic chlorination with sodium hypochlorite
Authors: Grbović G. , Trebše P. , Dolenc D. , Lebedev A. T. , Sarakha M.
Published: November 2013

The fate of modern personal care products in the environment is becoming a matter of increasing concern because of the growing production and assortment of these compounds. More and more chemicals of this class are treated as emerging contaminants. Transformation of commercially available products in the environment may result in the formation of a wide array of their metabolites. Personal care products in swimming pools and in drinking water reservoirs may undergo oxidation or chlorination. There is much data on the formation of more toxic metabolites from original low toxicity commercial products. Therefore, reliable identification of all possible transformation products and a thorough study of their physicochemical and biological properties are of high priority. The present study deals with the identification of the products of the aquatic chlorination of the hexyl 2‐[4‐(diethylamino)‐2‐hydroxybenzoyl]‐benzoate ultraviolet filter. High‐performance liquid chromatography/mass spectrometry (HPLC/MS) and HPLC/MS/MS with accurate mass measurements were used for this purpose. As a result, three chlorinated transformation products were identified. Copyright © 2013 John Wiley & Sons, Ltd.
Rapidly cleaving bovine two‐cell embryos have better developmental potential and a distinctive mRNA pattern
Authors: Orozco‐Lucero Ernesto , Dufort Isabelle , Robert Claude , Sirard Marc‐André
Published: November 2013

Mammalian embryos that rapidly reach the two‐cell stage in culture have a higher probability of becoming viable blastocysts. Our goal was to separate two‐cell bovine embryos based on their zygotic cleavage timing, and to assess their global mRNA levels. Following in vitro fertilization, all embryos that cleaved by 29.5 hpi (early) were cultured separately from those that divided at 46 hpi (late). The blastocyst rates were 46.1 ± 3.7% and 6.1 ± 3.4% for early‐ and late‐cleavers, respectively (P < 0.01). Seven replicates of selected two‐cell embryos were collected at each time point for microarray characterization (n = 4) and quantitative reverse‐transcriptase PCR (n = 3); the rest were left in culture for blastocyst evaluation. A total of 774 and 594 probes were preferentially present in early‐ and late‐cleaving embryos, respectively (fold change ± 1.5, P < 0.05), with important contrasts related to cell cycle, gene expression, RNA processing, and protein degradation functions. A total of 12 transcripts were assessed by quantitative PCR, of which ATM, ATR, CTNNB1, MSH6, MRE11A, PCNA, APC, CENPE, and GRB2 were in agreement with the hybridization results. Since most of these molecules are directly or indirectly associated with cell‐cycle regulation, DNA damage response, and transcription control, our results strongly suggest key roles for those biological functions in mammalian preimplantation development. Mol. Reprod. Dev. 81: 31–41, 2014. © 2013 Wiley Periodicals, Inc.
Physical, mechanical, and water absorption behavior of coir/glass fiber reinforced epoxy based hybrid composites
Authors: Bhagat Vineet Kumar , Biswas Sandhyarani , Dehury Janaki
Published: November 2013

Fiber reinforced polymer composites has been used in a variety of application because of their many advantages such as relatively low cost of production, easy to fabricate, and superior strength compare to neat polymer resins. Reinforcement in polymer is either synthetic or natural. Synthetic fiber such as glass, carbon, etc. has high specific strength but their fields of application are limited due to higher cost of production. Recently there is an increase interest in natural composites which are made by reinforcement of natural fiber. In this connection, an investigation has been carried out to make better utilization of coconut coir fiber for making value added products. The objective of the present research work is to study the physical, mechanical, and water absorption behavior of coir/glass fiber reinforced epoxy based hybrid composites. The effect of fiber loading and length on mechanical properties like tensile strength, flexural strength, and hardness of composites is studied. The experimental results reveal that the maximum strength properties is observed for the composite with 10 wt% fiber loading at 15 mm length. The maximum flexural strength of 63 MPa is observed for composites with 10 wt% fiber loading at 15 mm fiber length. Similarly, the maximum hardness value of 21.3 Hv is obtained for composites with 10 wt% fiber loading at 20 mm fiber length. Also, the surface morphology of fractured surfaces after tensile testing is examined using scanning electron microscope (SEM). POLYM. COMPOS., 35:925–930, 2014. © 2013 Society of Plastics Engineers
2‐Methoxynaphthylnaphthoquinone and its solvate: synthesis and structure–properties relationship
Authors: Demchuk Oleg M. , Justyniak I. , Miroslaw B. , Jasinski R.
Published: November 2013

Because of their unique visual optic and electronic properties, substituted quinones are commonly used as dyes and pigments; nevertheless, a theoretic background of relationship between the structures and optical properties of such compounds seems to be still undeveloped. Two crystalline forms of 2‐methoxynaphth‐1‐yl‐naphthoquinone (MNQ) have been synthesized and characterized by means X‐ray, NMR, UV–VIS, as well as, MS spectroscopy. The interpretation of intriguing optical properties of two crystalline forms of MNQ, based on detailed spectral and structural characterization, as well as, DFT and MP2 computations clearly connects the conformation of the molecules with their optical and electronic properties. Thus, flatter conformation, stabilized by crystal net force, favours the intense electron density transition from auxochrome to chromophore moiety (which corresponds excitation from HOMO to LUMO), as well as, favours the π‐stacking interaction, that eventually results in colour enhancement. At the same time, small molecules of solvents included into the crystal net allow molecules of arylnaphthoquinones to adopt less rigid conformation what has a dramatic optical outcome. Copyright © 2013 John Wiley & Sons, Ltd.
Poly(ether ketone)s bearing pendent sulfonate groups via copolyacylation of a sulfonated monomer and isomeric AB‐type comonomers
Authors: Zhang Zhenghui , Xu Tongwen
Published: November 2013

Poly(ether ketone)s bearing pendent sulfonate groups (SPEK‐x/y/z) have been successfully synthesized via copolyacylation of a presulfonated monomer SBP and two isomeric AB‐type self‐condensable comonomers, that is, 4‐phenoxybenzoic acid (p‐POBA) and 3‐phenoxybenzoic acid (m‐POBA). Proton‐exchange membranes (PEMs) with precisely controlled ion‐exchange capacity (IEC) and high strength can be readily prepared from these ionomers. PEMs prepared from p‐POBA other than m‐POBA exhibit much higher dimensional stability and proton conductivity at elevated temperature above 60 °C, showing prominent isomeric (para vs. meta) effects of polymer structural units. Furthermore, properties of PEMs prepared from p‐POBA are optimized by tuning IEC. SPEK‐1.0/2.2/0 with an IEC of 1.84 mmol g−1 exhibits acceptable swelling, much higher proton conductivity, and lower methanol permeability than commercial Nafion 115, implying potential application in direct methanol fuel cells. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 200–207
Ordering poly(trimethylsilyl styrene‐block‐D,L‐lactide) block copolymers in thin films by solvent annealing using a mixture of domain‐selective solvents
Authors: Cushen Julia D. , Wan Lei , Pandav Gunja , Mitra Indranil , Stein Gila E. , Ganesan Venkat , Ruiz Ricardo , Grant Willson C. , Ellison Christopher J.
Published: November 2013

Controlling the morphology, domain orientation, and domain size of block copolymer (BCP) thin films is desirable for many applications in nanotechnology. These properties can be tuned during solvent annealing by varying the solvent choice and degree of swelling which affect the effective miscibility and volume fraction of the BCP domains. In this work, we demonstrate with a bulk lamellae‐forming BCP, poly(4‐trimethylsilylstyrene‐block‐D,L‐lactide) (PTMSS‐b‐PLA), that varying the composition of a mixture of solvent vapors containing cyclohexane (PTMSS‐selective) and acetone (PLA‐selective), enables formation of perpendicularly oriented lamellae with sub‐20‐nm pitch lines. The BCP domain periodicity was also observed to increase by 30%, compared to bulk, following solvent annealing. Furthermore, solvent annealing alone is shown to induce a transition from a disordered to an ordered BCP. We rationalize our observations by hypothesizing that the use of a combination of domain selective solvent mixtures serves to increase the effective repulsion between the blocks of the copolymer. We furnish results from self‐consistent field theory calculations to support the proposed mechanism. © 2013 Wiley Periodicals, Inc. J. Polym. Sci. Part B: Polym. Phys. 2014, 52, 36–45
Factors Influencing Destruction of Triacetone Triperoxide (TATP)
Authors: Oxley Jimmie C. , Smith James L. , Brady Joseph E. , Steinkamp Lucus
Published: November 2013

Acid catalyzes the formation of triacetone triperoxide (TATP) from acetone and hydrogen peroxide, but acid also destroys TATP, and, under certain conditions, converts TATP to diacetone diperoxide (DADP). Addition of strong acids to TATP can cause an explosive reaction, while reaction with dilute acid reduces the decomposition rate so drastically that gentle destruction of TATP is impractical. However, combined use of dilute acid with slightly solvated TATP made gentle destruction of TATP feasible. Variables including acid type, concentration, solvent and ratios thereof have been explored, along with kinetics, in an attempt to provide a field‐safe technique for gently destroying this homemade primary explosive. The preferred method is moistening TATP with an alcoholic solution (aqueous methanol, ethanol, or iso‐propanol) followed by addition of 36 wt‐% hydrochloric acid. Preliminary experiments have shown the technique to be safe and effective for destruction of hexamethylene triperoxide diamine (HMTD), as well.
Predicting Solubility of Military, Homemade, and Green Explosives in Pure and Saline Water using COSMO‐RS
Authors: Alnemrat Sufian , Hooper Joseph P.
Published: November 2013

The conductor‐like screening model for real solvents (COSMO‐RS) has previously been shown to give accurate aqueous solubilities for a range of organic compounds using only quantum chemical simulation data. Application of this method for solid organic explosives, however, faces two difficulties; it requires correction for the free energy of fusion (a generally unknown quantity for these compounds) and it shows considerable error for common explosive classes such as nitramines. Herein we introduce a correction factor for COSMO‐RS that is applicable to a wide range of explosives, and requires no data beyond a quantum chemistry calculation. This modification allows COSMO‐RS to be used as a predictive tool for new proposed explosives or for systems lacking experimental data. We use this method to predict the temperature‐dependent solubility of solid explosives in pure and saline water to an average accuracy of approximately 0.25 log units at ambient temperature. Setschenow (salting‐out) coefficients predicted by this method show considerable improvement over previous COSMO‐RS results, but are still slightly overestimated compared to the limited experimental data available. We apply this method to a range of military, homemade, and “green” explosives that lack experimental seawater solubility data, an important property for environmental fate and transport modeling.
Effect of Initial Oxide Layer on Ignition and Combustion of Boron Powder
Authors: Ao Wen , Wang Yang , Li Heping , Xi Jianfei , Liu Jianzhong , Zhou Junhu
Published: November 2013

Only few data exist for experimental studies on ignition and combustion of boron particles with initial oxide thickness. The oxidation, ignition and combustion characteristics including the onset temperatures, weight gain, apparent activation energy, emission spectra during combustion, and ignition delay time of crystalline boron powders with different initial oxide thickness (x0) were studied by a laser ignition and thermogravimetric (TG) analyses. Simulations of the kinetics of oxide layer during boron ignition were conducted using a common model. The results indicated that the onset temperature was approximately 775 °C, independent of x0. The total weight gain decreased with increasing x0, whereas the weight gain at 775 °C did not change. The apparent activation energy was found to be insensitive to x0 and had a constant value of about 210 kJ mol−1. The intensity of the emission spectra gradually decreased while the ignition delay time increased with increasing x0. Numerical simulation showed that the removal rate of oxide layer enhanced with increasing x0. The experimental results revealed that the oxidation of boron powder was no diffusion‐controlled process at low temperatures. But the diffusion of oxygen could become important to the oxidation reaction at high temperatures
Explosion from a smoldering silo fire
Authors: Ogle Russell A. , Dillon Scott E. , Fecke Mark
Published: November 2013

Many organic granular materials are susceptible to self‐heating when stored in silos. Under the right environmental conditions self‐heating can lead to spontaneous ignition and smoldering combustion. This is a case study of an explosion that occurred in a grain storage silo with a smoldering fire. Although the hazards of combustible dust are relatively well recognized, the explosion hazard presented by a smoldering fire is less well known. There were two explosions in this incident: a primary explosion involving carbon monoxide and smoke generated by the smoldering fire, and a secondary explosion fueled by combustible dust. The explosion caused both injuries to personnel and significant property damage. This article discusses the causal factors for the explosion and the lessons learned for effectively monitoring and responding to a smoldering fire in a silo. The potential explosion hazard of the carbon monoxide and smoke generated by a smoldering fire is emphasized. © 2013 American Institute of Chemical Engineers Process Saf Prog 33: 94–103, 2014
Synthesis and alkylation of aza‐glycinyl dipeptide building blocks
Authors: Garcia‐Ramos Yesica , Lubell William D.
Published: November 2013

Aza‐glycinyl dipeptides are useful building blocks for the synthesis of a diverse array of azapeptides. The construction of the aza‐glycine residue is however challenging, because of the potential for side reactions, such as those leading to formation of oxadiazalone, hydantoin and symmetric urea by‐products. Employing N,N′‐disuccinimidyl carbonate to activate benzophenone hydrazone, we have developed a more efficient approach for the synthesis of aza‐glycinyl dipeptides. Alkylation of the semicarbazone of the resulting protected aza‐glycinyl dipeptides using tetraethylammonium hydroxide and propargyl bromide provided an efficient entry into the aza‐propargylglycinyl peptide building blocks, which have served previously in various reactions including Sonogashira cross‐couplings, dipolar cycloadditions and intramolecular exo‐dig cycloadditions to furnish a variety of azapeptide building blocks. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.
Farm Size, Land Reallocation, and Labour Migration in Rural China
Authors: Yan Xiaohuan , Bauer Siegfried , Huo Xuexi
Published: November 2013

This paper explores the factors that determine a farm household migration decision, particularly the influence of the current land tenure system in China. Land endowment per labour is used to measure farm size. Reallocation times and expectation of future land reallocation are used to measure the land reallocation situation. Data used in this study are from a farm household survey conducted in 2009 in 17 villages in Northeast Henan province. By using a Heckman two‐stage model, the empirical findings show that there are some differences in terms of the magnitude and direction of determinants significantly affecting the decision to migrate and its duration. China's land tenure arrangements are based on egalitarian land distribution and frequent reallocation stimulates rather than deters migration in the case of land rental market imperfections. However, it is the main reason for the unique temporary and individual migration patterns. With the development of land rental markets, the importance of land transferability becomes prominent. Policies aimed at improving land security and promoting land transfer will also benefit rural labour emigration. Other factors that also have significant influence on labour migration are household size, number of household dependents, household assets and whether a household has a land‐use contract. Copyright © 2013 John Wiley & Sons, Ltd.