bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extrusion‐based differences in two types of nylon 6 capillary‐channeled polymer (C‐CP) fiber stationary phases as applied to the separation of proteins via ion exchange chromatography
Authors: Schadock‐Hewitt Abby J. , Pittman Jennifer J. , Stevens Kathryn A. , Marcus R. Kenneth 
Published: September 2012

AbstractNylon 6 capillary‐channeled polymer (C‐CP) fibers used as the stationary phase in high‐performance liquid chromatography protein separations have been investigated. A difference in chromatographic behavior between two (presumably identical) nylon 6 C‐CP fibers, designated simply as nylon 6A and nylon 6B, reveals unknown differences in their chemical and physical nature as proteins are less retained on the latter. The possible differences are evaluated through several test methods, including Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), mechanical testing, MALDI‐TOF mass spectrometry, an organic reaction with ninhydrin, and dilute solution viscometry. Nylon 6B is shown to be a larger perimeter, stronger fiber, yet in a 200 mm, 0.8 mm i.d. column having an interstitial fraction of ∼0.6, it has an available surface area of ∼189 cm2, while nylon 6A is almost double that at ∼374 cm2. It is revealed that when in amorphous form, the base polymers have very comparable FTIR and DSC characteristics. When in their solid, extruded fiber form there are significant differences found in crystallinity, tensile strength, molecular weight distribution, and end group density. Nylon 6A is a lower molecular weight fiber, which results in ∼1.3× more amine end groups than nylon 6B. It is the end group density that ultimately determines the separation qualities. These results imply that both a difference in base nylon 6 molecular weight and also the fiber extrusion process have a significant influence on the performance of nylon 6 C‐CP fiber separation of proteins via ion exchange chromatography. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Systemic sclerosis endothelial cells recruit and activate dermal fibroblasts by induction of a connective tissue growth factor (CCN2)/transforming growth factor β–dependent mesenchymal‐to‐mesenchymal transition
Authors: Serratì Simona , Chillà Anastasia , Laurenzana Anna , Margheri Francesca , Giannoni Elisa , Magnelli Lucia , Chiarugi Paola , Dotor Javier , Feijoo Esperanza , Bazzichi Laura , Bombardieri Stefano , Kahaleh Bashar , Fibbi Gabriella , Del Rosso Mario 
Published: September 2012

AbstractObjectiveClinical evidence suggests that the vascular abnormalities of systemic sclerosis (SSc) precede the onset of fibrosis, but molecular cues accounting for a possible vascular connection of SSc fibrosis have been elusive, although they have been searched for intensively. Since we had previously shown that connective tissue growth factor (CCN2), endowed with fibroblast‐oriented activities, was overexpressed by endothelial cells (ECs) from SSc patients, we undertook this study to investigate its role and mechanisms in fibroblast activation.MethodsNormal fibroblasts were challenged with conditioned medium of normal microvascular ECs (MVECs) and MVECs obtained from SSc patients with the diffuse form of the disease. Fibroblast invasion was studied using the Boyden chamber Matrigel assay. Fibroblast activation was evaluated by Western blotting and immunofluorescence of α‐smooth muscle actin (α‐SMA), vimentin, and type I collagen. Matrix metalloproteinase (MMP) production was evaluated by zymography and reverse transcription–polymerase chain reaction. Signal transduction and activation of the small GTPases RhoA and Rac1 were studied by Western blotting. Inhibition of SSc MVEC conditioned medium–dependent fibroblast activation was obtained by anti‐CCN2 antibodies and the transforming growth factor β (TGFβ) antagonist peptide p17.ResultsSSc MVEC CCN2 stimulated fibroblast activation and invasion. Such activities depended on CCN2‐induced overexpression of TGFβ and its type I, II, and III receptors combined with overproduction of MMP‐2 and MMP‐9 gelatinases. All of these effects were reversed by the TGFβ antagonist peptide p17. Motility increase required Rac1 activation and RhoA inhibition and was inhibited by an MMP inhibitor. These features connoted a mesenchymal style of cell invasion. Since fibroblast activation also fostered overexpression of α‐SMA, vimentin, and type I collagen, the CCN2‐dependent increase in fibroblast activities recapitulated the characteristics of a mesenchymal‐to‐mesenchymal transition.ConclusionSSc MVECs recruit and activate dermal fibroblasts by induction of a CCN2/TGFβ‐dependent mesenchymal‐to‐mesenchymal transition.
Study on the ternary system of MoO42‐–enzyme–PdCl2 by resonance Rayleigh scattering, second‐order scattering and frequency‐doubling scattering spectra and its analytical application
Authors: Wang Yaqiong , Liu Shaopu , Liu Zhongfang , Hu Xiaoli , Xue Jiaxing , Tian Jing 
Published: September 2012

ABSTRACTIn pH 4.0 Britton–Robinson buffer medium, PdCl2 was able to react with enzymes (EZ) such as lysozyme (LYSO) and papain (PAP) to form a coordination complex (EZ–PdCl2), which further reacted with MoO42‐ to form a ternary complex (MoO42‐–EZ–PdCl2). As a result, the absorption and fluorescence spectra changed; new spectra of resonance Rayleigh scattering (RRS), second‐order scattering (SOS) and frequency‐doubling scattering (FDS) appeared and their intensities were enhanced greatly. The maximum RRS, SOS and FDS wavelengths of two ternary complexes were located at 310, 560 and 350 nm, respectively. The increments of scattering intensity were directly proportional to the concentrations of EZ within certain ranges. The detection limits (3σ) of LYSO and PAP were 4.5 and 14.0 ng/mL (RRS method), 9.6 and 57.8 ng/mL (SOS method), and 5.2 and 106.0 ng/mL (FDS method). Taking the MoO42‐–LYSO–PdCl2 system, which was more sensitive, as an example, the effects of coexisting substances were evaluated. The methods showed excellent selectivity. Accordingly, new rapid, convenient, sensitive and selective scattering methods for the determination of LYSO and PAP were proposed and applied to determine LYSO in egg white with satisfactory results. The reaction mechanism and basis of the enhancement of scattering were discussed. Copyright © 2012 John Wiley & Sons, Ltd.
Systematic review and meta-analysis of outcomes following emergency surgery for Clostridium difficile colitis
Authors: Bhangu A , Nepogodiev D , Gupta A , Torrance A , Singh P 
Published: September 2012

Abstract

Background
Only a small proportion of patients with severe Clostridium difficile infection (CDI) undergo emergency surgery, the timing and nature of which is unclear. The aim of this study was to describe the operations performed and to identify factors predictive of death following emergency surgery for CDI.

Methods
A systematic review of published literature was performed for studies comparing survivors and non-survivors of emergency surgery for CDI. Meta-analysis was carried out for 30-day and in-hospital mortality.

Results
Overall 31 studies were included, which presented data on a total of 1433 patients undergoing emergency surgery for CDI. Some 1·1 per cent of all patients with CDI and 29·9 per cent with severe CDI underwent emergency surgery, although rates varied between studies (0·2–7·6 and 2·2–86 per cent respectively). The most commonly performed operation was total colectomy with end ileostomy (89·0 per cent, 1247 of 1401 detailed surgical procedures). When total colectomy with end ileostomy was not performed, reoperation to resect further bowel was needed in 15·9 per cent (20 of 126). Where described, the 30-day mortality rate was 41·3 per cent (160 of 387). Meta-analysis of high-quality studies revealed that the strongest predictors of postoperative death were those relating to preoperative physiological status: preoperative intubation, acute renal failure, multiple organ failure and shock requiring vasopressors.

Conclusion
This systematic review supports total colectomy with end ileostomy as the primary surgical treatment for patients with severe CDI; other surgical procedures are associated with high rates of reoperation and mortality. Less extensive surgery may have a role in selected patients with earlier-stage disease.
Proteome analysis of altered proteins in streptozotocin‐induced diabetic rat kidney using the fluorogenic derivatization–liquid chromatography–tandem mass spectrometry method
Authors: Tsai Pei‐Yun , Chen Shih‐Ming , Chen Hsiang‐Yin , Li Yi‐Chieh , Imai Kazuhiro , Hsu Kuang‐Yang , Lee Jen‐Ai 
Published: September 2012

ABSTRACTTo find new molecular markers for early diagnosis of diabetic nephropathy, we applied fluorogenic derivatization–liquid chromatography–tandem mass spectrometry to identify the differentially expressed proteins in the kidney of control and streptozotocin‐induced diabetic rats. The Sprague–Dawley rats were injected with the sodium citrate buffer or streptozotocin and then killed after 1, 4, 12 and 24 weeks. The results showed that seven proteins were significantly changed after 1 week of injection. Only one protein had significantly changed after 4 weeks of injection. However, after 12 weeks of injection, the number of altered proteins rose to 10. After 24 weeks of injection, 18 proteins had altered significantly. Five common proteins were significantly altered at week 12 and 24 after injection, respectively. Importantly, these proteins appeared prior to microalbuminuria and may serve as new biomarkers that are able to improve early detection of and new drug development for diabetic‐related nephropathy. Copyright © 2012 John Wiley & Sons, Ltd.
The use of a new, modified Dittmer–Lester spray reagent for phospholipid determination by the TLC image analysis technique
Authors: Dyńska‐Kukulska Katarzyna , Ciesielski Witold , Zakrzewski Robert 
Published: September 2012

ABSTRACTA new phospholipid‐specific spray reagent is described. A new phospholipid‐specific spray reagent, which is a modification of the Dittmer–Lester reagent, is described in authors' studies. The difference between these two reagents is in the addition of tin (II) chloride to the proposed spray reagent. The use of the described spray reagent together with an image analysis technique allows not only for qualitative, but also for quantitative, determination of major phospholipid classes. Separation of phosphatidylserine (PS), phosphatidylethanolamine (PE) and phosphatidylcholine (PC) was conducted on an HPTLC plate with a mixture of chloroform, methanol and 25% ammonia solution in a volume ratio of 65:25:4 as mobile phase. The calibration curves were linear in the ranges of 5.0–25.0, 1.5–15.0 and 1.0–20.0 µg/spot for PC, PS and PE, respectively. The use of the new spray reagent resulted also in lower limits of detection than the standard molybdenum method for the investigated phospholipids. The proposed method was used to determine the amount of PS in the dietary supplement ‘Session’, and of PS, PE and PC in biological samples, with good results. Copyright © 2012 John Wiley & Sons, Ltd.
ISO 26000 and the Standardization of Strategic Management Processes for Sustainability and Corporate Social Responsibility
Authors: Hahn Rüdiger 
Published: September 2012

ABSTRACTThe standard ISO 26000 aims to provide guidance on social responsibility and help all types of organizations contribute to sustainable development. Such guidance is important since there is still no consistent understanding of what corporate sustainability and social responsibility (CSSR) encompass. Many companies lack a strategic approach to CSSR and instead follow unsystematic procedures; thus, formal strategic planning could improve operational efficiency.Against this background, this article critically examines the contribution of ISO 26000 to the strategic management processes of different types of companies. This allows the potential of ISO 26000 for guiding companies on their path to sustainability to be identified. The analysis shows that the standard is most useful for beginners in CSSR. However, ISO 26000 does not cover the entire range of strategic management processes. Instead, the standard is especially helpful for internal and external analyses and in providing starting points for implementing sustainability strategies. Copyright © 2012 John Wiley & Sons, Ltd and ERP Environment.
Fibrous Supramolecular Hemoprotein Assemblies Connected with Synthetic Heme Dimer and Apohemoprotein Dimer
Authors: Onoda Akira , Takahashi Akinori , Oohora Koji , Onuma Yoshitaka , Hayashi Takashi 
Published: September 2012

AbstractSupramolecular hemoprotein assemblies via hemeheme pocket interaction were prepared by synthetic heme dimers containing a linker with charged amino acids and apohemoprotein disulfide dimers. The mixture of the negatively charged heme dimer and the apomyoglobin dimer provides heterotropic fibrous hemoprotein assemblies, which were characterized by size‐exclusion chromatography (SEC) and atomic force microscopy (AFM).
Demetalation of Chlorophyll Pigments
Authors: Saga Yoshitaka , Tamiaki Hitoshi 
Published: September 2012

AbstractNatural chlorophylls (Chls) and bacteriochlorophyll (BChls), which are major pigments in photosynthesis, possess a central Mg (or Zn) in their cyclic tetrapyrrole macrocycles. Removal of the central metal atom from chlorophyllous pigments, called pheophytinization, is a biologically important reaction in that it allows production of the primary electron acceptors in photosystem II(‐type) reaction centers and is one of the crucial steps in the Chl degradation pathway. Pheophytinization in processed and postharvest foods derived from vegetables and fruits has attracted considerable attention in agricultural and food chemistry from the viewpoints of maintenance of their color level and evaluation by consumers. In this review, we focus on in vivo demetalation reactions and demetalated products of chlorophyllous pigments. In addition, we summarize kinetic studies on in vitro demetalation of natural (B)Chl molecules and their synthetic analogs under acidic conditions.
3‐Fluorotyrosine as a Complementary Probe of Hemoglobin Structure and Dynamics: A 19F‐NMR Study of Synechococcus sp. PCC 7002 GlbN
Authors: Pond Matthew P. , Wenke Belinda B. , Preimesberger Matthew R. , Rice Selena L. , Lecomte Juliette T. J. 
Published: September 2012

AbstractThe hemoglobin from the cyanobacterium Synechococcus sp. PCC 7002 (GlbN) contains three tyrosines (Tyr5, Tyr22, and Tyr53), each of which undergoes a structural rearrangement when the protein binds an exogenous ligand such as cyanide. We explored the use of 3‐fluorotyrosine and 19F‐NMR spectroscopy for the characterization of GlbN. Assignment of 19F resonances in fluorinated GlbN (GlbN*) was achieved with individual Tyr5Phe and Tyr53Phe replacements. We observed marked variations in chemical shift and linewidth reflecting the dependence of structural and dynamic properties on oxidation state, ligation state, and covalent attachment of the heme group. The isoelectronic complexes of ferric GlbN* with cyanide and ferrous GlbN* with carbon monoxide gave contrasting spectra, the latter exhibiting heterogeneity and enhanced internal motions on a microsecond‐to‐millisecond time scale. The strength of the H‐bond network involving Tyr22 (B10) and bound cyanide was tested at high pH. 3‐Fluorotyrosine at position 22 had a pKa value at least 3 units higher than its intrinsic value, 8.5. In addition, evidence was found for long‐range communication among the tyrosine sites. These observations demonstrated the utility of the 3‐fluorotyrosine approach to gain insight in hemoglobin properties.
Native N‐Terminus Nitrophorin 2 from the Kissing Bug: Similarities to and Differences from NP2(D1A)
Authors: Berry Robert E. , Muthu Dhanasekaran , Shokhireva Tatiana K. , Garrett Sarah A. , Zhang Hongjun , Walker F. Ann 
Published: September 2012

AbstractThe first amino acid of mature native nitrophorin 2 is aspartic acid, and when expressed in E. coli, the wild‐type gene of the mature protein retains the methionine‐0, which is produced by translation of the start codon. This form of NP2, (M0)NP2, has been found to have different properties from its D1A mutant, for which the Met0 is cleaved by the methionine aminopeptidase of E. coli (R. E. Berry, T. K. Shokhireva, I. Filippov, M. N. Shokhirev, H. Zhang, F. A. Walker, Biochemistry 2007, 46, 6830). Native N‐terminus nitrophorin 2 ((ΔM0)NP2) has been prepared by employing periplasmic expression of NP2 in E. coli using the pelB leader sequence from Erwinia carotovora, which is present in the pET‐26b expression plasmid (Novagen). This paper details the similarities and differences between the three different N‐terminal forms of nitrophorin 2, (M0)NP2, NP2(D1A), and (ΔM0)NP2. It is found that the NMR spectra of high‐ and low‐spin (ΔM0)NP2 are essentially identical to those of NP2(D1A), but the rate and equilibrium constants for histamine and NO dissociation/association of the two are different.
Directing the Biosynthesis of Putrebactin or Desferrioxamine B in Shewanella putrefaciens through the Upstream Inhibition of Ornithine Decarboxylase
Authors: Soe Cho Z. , Pakchung Amalie A. H. , Codd Rachel 
Published: September 2012

AbstractTo manage iron acquisition in an oxic environment, Shewanella putrefaciens produces the macrocyclic dihydroxamic acid putrebactin (PB) as its native siderophore. In this work, we have established the siderophore profile of S. putrefaciens in cultures augmented with the native PB precursor putrescine and in putrescine‐depleted cultures. Compared to base medium, PB increased by two‐fold in cultures of S. putrefaciens with 10 mM NaCl and 20 mM exogenous putrescine. In cultures augmented with 1,4‐diaminobutan‐2‐one (DAB), PB decreased with only 0.02‐fold PB detectable at 10 mM DAB. As an ornithine decarboxylase (ODC) inhibitor, DAB depleted levels of endogenous putrescine which attenuated downstream PB assembly. Under putrescine‐depleted conditions, S. putrefaciens produced as its replacement siderophore the cadaverine‐based desferrioxamine B (DFO‐B), as characterised by ESI‐MS of the FeIII‐loaded form (m/zobs 614.13; m/zcalc 614.27). A third siderophore, independent of DAB, was observed in low levels. LC/MS Analysis of the FeIII‐loaded extract gave m/zobs 440.93, which, formulated as a 1 : 1 FeIII complex with a macrocyclic dihydroxamic acid, comprising one putrescine‐ and one cadaverine‐based precursor (m/zcalc 440.14). These results show that the production of native PB or non‐native DFO‐B by S. putrefaciens can be directed though upstream inhibition of ODC. This approach could be used to increase the molecular diversity of siderophores produced by S. putrefaciens and to map alternative diamine‐dependent metabolites.
Unusually High‐Affinity Mg2+ Binding at the AU‐Rich Sequence within the Antiterminator Hairpin of a Mg2+ Riboswitch
Authors: Korth Maximiliane M. T. , Sigel Roland K. O. 
Published: September 2012

AbstractMg2+‐Responsive riboswitches represent a fascinating example of bifunctional RNAs that sense Mg2+ ions with high selectivity and autonomously regulate the expression of Mg2+‐transporter proteins. The mechanism of the mgtA riboswitch is scarcely understood, and a detailed structural analysis is called for to study how this RNA can selectively recognize Mg2+ and respond by switching between two alternative stem loop structures. In this work, we investigated the structure and Mg2+‐binding properties of the lower part of the antiterminator loop C from the mgtA riboswitch of Yersinia enterocolitica by solution NMR and report a discrete Mg2+‐binding site embedded in the AU‐rich sequence. At the position of Mg2+ binding, the helical axis exhibits a distinct kink accompanied by a widening of the major groove, which accommodates the Mg2+‐binding pocket. An unusually large overlap between two adenine residues on the opposite strands suggests that the bending may be sequence‐induced by strong stacking interactions, enabling Mg2+ to bind at this so‐far not described metal‐ion binding site.
Structure of Malaria Pigment and Related Propanoate‐Linked Metalloporphyrin Dimers
Authors: Bohle D. Scott , Dodd Erin L. , Stephens Peter W. 
Published: September 2012

AbstractMalaria pigment, the heme detoxification product of malaria's invasion, digestion, and growth inside mammalian red blood cells, is an insoluble phase of iron(III)protoporphyrin‐IX. Even though its structure was determined in 2000 by powder X‐ray diffraction, significant questions remain about its formation and possible interaction with quinoline antimalarial drugs. A recent structural study, also with X‐ray powder diffraction, has reconfirmed that the material isolated from the parasite is isostructural with its synthetic equivalent. It was recently suggested that other isomers may also be formed and may be present in synthetic samples. In particular, a series of stereoisomers are possible for the arrangement of vinyl groups on the periphery of the dimerized porphyrin rings. In principle, any given dimer can have vinyl groups at the α or β sites, and at γ or δ sites. In this paper, several models are evaluated, both biphasic and homogeneous methyl/vinyl disorder, against several sets of diffraction data, both published and new. We conclude that methyl/vinyl disorder is intrinsic to the system, and that the evidence at hand does not support the existence of any other crystalline isomers in carefully prepared samples of either natural or synthetic samples. Finally, the porphyrinporphyrin interactions are evaluated using Scheidt's indicies for porphyrin π‐stacking, and we find modest to weak π‐interactions in these condensed phases.
ChemInform Abstract: Crystal Structure and Magnetic Properties of Novel R3Co2.2Si1.8 Compounds (R: Y, Gd—Tm).
Authors: Morozkin A. V. , Yao Jinlei , Mozharivskyj Y. 
Published: September 2012

AbstractThe new compound Dy3Co2.2Si1.8 and the other title phases are synthesized by arc‐melting of stoichiometric mixtures of the elements followed by annealing at 1070 K for 120 h in argon atmosphere.
ChemInform Abstract: Multiple Cation and Anion Substitutions into the Structures of Bi2WO6 and PbBi3WO8Cl.
Authors: Charkin Dmitri O. , Lebedev Dmitri N. , Kazakov Sergey M. 
Published: September 2012

AbstractSimultaneous substitution of W by U and Bi3+ by La3+ in the title compounds leads to the new compound Bi1.5La0.5UO6 and several new solid solutions, which are characterized by powder XRD and Raman spectroscopy.
ChemInform Abstract: Surprising Acid/Base and Ion‐Sequestration Chemistry of Sn94‐: HSn93‐, Ni@HSn93‐, and the Sn93‐ Ion Revisited.
Authors: Kocak F. Sanem , Downing Domonique O. , Zavalij Peter , Lam Yiu‐Fai , Vedernikov Andrei N. , Eichhorn Bryan 
Published: September 2012

AbstractK4Sn9 dissolves in en to give equilibrium mixtures of the diamagnetic HSn93‐ ion along with KxSn9(4‐x)‐ ion pairs (x = 0, 1, 2, 3).
ChemInform Abstract: α‐MnO2 Nanotubes: High Surface Area and Enhanced Lithium Battery Properties.
Authors: Li Lihong , Nan Caiyun , Lu Jun , Peng Qing , Li Yadong 
Published: September 2012

AbstractThe title nanotubes are hydrothermally prepared from a mixture of KMnO4, NH4H2PO4, Bu4NOH, and H2O (autoclave, 180 °C, 48 h).
ChemInform Abstract: Simple Replacement Reaction for the Preparation of Ternary Fe1‐xPtRux Nanocrystals with Superior Catalytic Activity in Methanol Oxidation Reaction.
Authors: Wang Di‐Yan , Chou Hung‐Lung , Lin Yen‐Chen , Lai Feng‐Ju , Chen Ching‐Hsiang , Lee Jyh‐Fu , Hwang Bing‐Joe , Chen Chia‐Chun 
Published: September 2012

AbstractFe1‐xPtRux (x = 25, 29, 43) nanocrystals are prepared from mixtures of FePt nanocrystals (obtained from Pt(acac)2 and Fe(CO)5 in a mixture of 1,2‐hexadecanediol, dioctyl ether, oleylamine, and oleic acid at 300 °C for 30 min) in toluene and RuCl3 in EtOH (85 °C, 3, 10, or 15 h).