bluuebunny/crossref_metadata_2025 huggingface dataset:
The Reactivity of Primary and Secondary Amines, Secondary Phosphanes and N‐Heterocyclic Carbenes towards Group‐13 Metal(I) Halides
Authors: Baker Robert J. , Bettentrup Helga , Jones Cameron
Published: June 2003

The reactions of a variety of primary and secondary amines and secondary phosphanes with “GaI” have been examined. In all cases disproportionation reactions occurred which led to the gallium(II) iodide complexes [Ga2I4(L)2] [L = NCyH2, NtBuH2, NCy2H, PCy2H or PtBu2H (Cy = cyclohexyl)]. All complexes have been crystallographically characterised and have been shown to be dimers possessing Ga−Ga bonds. The reaction of the sterically hindered N‐heterocyclic carbene IPr [:CN(Ar)C2H2N(Ar) (Ar = C6H3iPr2‐2,6)] with “GaI” was also carried out and the novel salt [Ga2I5(IPr)][IPrH] was formed in good yield and crystallographically characterised. Finally, the related reaction of the less hindered cyclic carbene IMe [:CN(Me)C2Me2N(Me)] with InCl gave a low yield of the crystallographically characterised salt [{InCl(IMe)}2(μ‐Cl)(μ‐O)][Cl] which presumably forms due to the presence of adventitious oxygen in the reaction mixture. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
New Bis(mercaptoimidazolyl)(pyrazolyl)borate Ligands and Their Zinc Complex Chemistry
Authors: Shu Mouhai , Walz Rainer , Wu Biao , Seebacher Jan , Vahrenkamp Heinrich
Published: June 2003

Nine new tripodal NS2 ligands of the bis(mercaptoimidazolyl)(pyrazolyl)borate type with varying 3‐R‐mercaptoimidazolyl moieties were prepared as their potassium salts. Treatment with zinc salts yielded the complex types L·Zn−Cl, L·Zn−I, L·Zn−ONO2, L·Zn−OClO3 and [L·Zn(imidazole)]ClO4. Attempts at the formation of L·Zn−OH or cationic L·Zn complexes resulted in dismutation and formation of ZnL2 complexes. Hydrolytic destruction yielded one [OZn4(thiooimidazolate)6] complex. The ZnS2NO coordination which is present in the enzyme‐substrate complex of alcohol dehydrogenase could be successfully modelled by an [L·Zn(C2H5OH)]+ complex. The L·Zn−X complexes showed very low catalytic activity in the dehydrogenation of 2‐propanol or the hydrogenation of p‐nitrobenzaldehyde. The new compounds were identified by a total of 12 structure determinations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
The First One‐Dimensional Molecular Material Featuring Maleonitriledithiolate as a Subunit Exhibiting Metamagnetic‐Like Behavior
Authors: Xie Jingli , Ren Xiaoming , Gao Song , Zhang Wenwei , Li Yizhi , Lu Changsheng , Ni Chunlin , Liu Wenlong , Meng Qingjin , Yao Yuangen
Published: June 2003

An ion‐pair complex [FBzPyNH2][Ni(mnt)2] {[FBzPyNH2]+ = [1‐(4′‐fluorobenzyl)‐4‐amino]pyridinium and mnt2− = maleonitriledithiolate} has been obtained by I2 oxidation of the corresponding dianion complex. It forms a wellsegregated stacking column structure in the solid state, and exhibits antiferromagnetic ordering below 2.5 K. It is the first complex in this series of complexes containing a maleonitriledithiolate dianion that exhibits metamagnetism. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Toolbox for exchanging constituent fatty acids in lecithins
Authors: Doig Steven D. , Diks Rob M. M.
Published: June 2003

Since the compositional variety of phospholipids in native lecithins is limited, and structurally diverse synthetic phospholipids are expensive, the aim of this work was to develop a lecithin modification toolbox capable of modifying the fatty acid composition of native lecithins at a convenient lab‐scale of 10‐100 g. Starting with the native phospholipids of soybean lecithin, two types of fatty acid modification were carried out using either phospholipase A2 from porcine pancreas or a lipase from Rhizopus oryzae. The former was immobilised onto celite and used to selectively hydrolyse the sn‐2 positioned fatty acid and the latter, commercially available in an immobilised form, was used to transesterify novel fatty acids onto the sn‐1 position.

The degree of phospholipid hydrolysis could be controlled between 5 and 95% by varying the contact time with the biocatalyst. A key parameter was the water concentration. By avoiding the presence of a bulk phase of water, emulsion formation was prevented and so simple product recovery was possible. However, sufficient water was required in order to maintain the water activity above 0.2, and because phospholipids increased the polarity of the solvent (hexane), it was necessary to add water in proportion to the lecithin concentration. During transesterification with methyllaurate, up to 43% lauric acid could be incorporated and although the recovery of fully acylated phospholipids was only 28%, due to the formation of hydrolysis products, they were isolated using solvent partitioning in hexane/isopropanol/water. The temperature was important in determining the relative rates of hydrolysis and transesterification and a lower temperature (40 °C) was favourable as the rate of hydrolysis was lowered without affecting the rate of transesterification.
Solid fat content in fats and oils ‐ determination by pulsed nuclear magnetic resonance spectroscopy [C‐IV 3g (2003)]
Authors: Fiebig Hans‐Jochen , Lüttke Jens
Published: June 2003

The “Joint Committee for the Analysis of Fats, Oils, Fatty products, Related Products and Raw Materials (GA FETT)” has developed the following method for the determination of the Solid Fat Content (SFC) in fats and oils. It is intended to include this method in Section C, Chapter IV of the German Standard Methods. The method reflexes the need of the fats and oils industry to get fast results and was tested in an interlaboratory test with 16 laboratories from 6 European countries.
Assessment and management of self‐harm in older adults attending accident and emergency: a comparative cross‐sectional study
Authors: Marriott Richard , Horrocks Judith , House Allan , Owens David
Published: June 2003

Objective

Older people who undertake self‐harm are at higher suicide risk than are younger patients. This study examines whether this greater risk is reflected in the assessment and after‐care that older patients receive when they attend accident and emergency.

Method

This cross‐sectional study, set in the two accident and emergency departments in a large industrial city in Northern England, compared 141 consecutive attendances due to self‐harm among older patients (aged 55 years and over) with a random sample of 125 attendances of younger people (aged 15–54) attending because of self‐harm. Data were drawn from accident and emergency records and from psychiatric and general hospital casenotes.

Results

Compared with the younger group, older patients were significantly more likely to be admitted from accident and emergency to the general hospital, to receive a specialist assessment whilst at the hospital, and to be offered psychiatric after‐care—either as a psychiatric in‐patient or an out‐patient.

Conclusions

Fortunately, older people attending accident and emergency following self‐harm seemed likely to receive psychosocial assessment from a mental health specialist, and they were much more likely than younger patients to be offered after‐care. Hospitals will need to monitor accident and emergency and other records if they are to check that their services are responding to the high risks seen in older patients. Copyright © 2003 John Wiley & Sons, Ltd.
Prescription practices of diagnostic imaging in dementia: a survey of 47 Alzheimer's Centres in Northern Italy
Authors: Riello R. , Albini C. , Galluzzi S. , Pasqualetti P. , Frisoni G. B.
Published: June 2003

Background

To date, there are no data at the national or European level on the prescription practices of imaging (CT, MR, and SPET) in the diagnosis of cognitively impaired elderly patients.

Methods

We addressed prescription practices of diagnostic imaging in 47 Alzheimer's Centres in Northern Italy, with an ad‐hoc questionnaire.

Results

The use of imaging in new cases was relatively intensive: 62% of the Alzheimer's Centres prescribed CT to more than 95% of cases, 24% prescribed MR to more than 33% of cases, and 33% prescribed SPET to more than 5% of cases. A minority of Alzheimer's Centres (n = 3, 6%) prescribed imaging to less than 100% of new cases. The association between onsite scanner availability and frequency of prescription increased from CT (Odds ratio (OR) = 1.8) through MR (OR = 2.4) to SPET (OR = 4.6), although only the latter was significant (95% confidence interval (CI) 1.2–17.7, p = 0.003). Patient‐related factors (age, severity of cognitive impairment, and clinical suspicion of cerebrovascular disease) influenced prescription of structural imaging in 30–53% of Alzheimer's Centres and organizational factors (onsite scanner availability, and waiting list) in a similar proportion (32 and 43% respectively).

Conclusions

Organizational factors play a relevant role in the prescription of imaging exams in patients with cognitive impairment and, at least for CT, the perceived diagnostic added value is rather low, suggesting a high degree of uncertainty in the clinical use of imaging techniques. Copyright © 2003 John Wiley & Sons, Ltd.
Party loyalty as habit formation
Authors: Shachar Ron
Published: June 2003

In most democracies, at least two out of any three individuals vote for the same party in sequential elections. This paper presents a model in which vote‐persistence is partly due to the dependence of the utility on the previous voting decision. This dependence is termed ‘habit formation’. The model and its implications are supported by individual‐level panel data on the presidential elections in the USA in 1972 and 1976. For example, it is found that the voting probability is a function of the lagged choice variable, even when the endogeneity of the lagged variable is accounted for, and that the tendency to vote for different parties in sequential elections decreased with the age of the voter. Furthermore, using structural estimation the effect of habit is estimated, while allowing unobserved differences among respondents. The structural habit parameter implies that the effect of previous votes on the current decision is quite strong. The habit model fits the data better than the traditional ‘party identification’ model. Copyright © 2003 John Wiley & Sons, Ltd.
Lipase production in continuous culture of Candida rugosa
Authors: Montesinos JL , Dalmau E , Casas C
Published: June 2003

The yeast Candida rugosa produces multiple extracellular lipases. The production of extra‐ and intracellular lipases was investigated in continuous cultures using a sole or different mixtures of carbon sources. Also, the effect of different C:N ratios was tested. Lipase productivity in continuous cultures increased by 50% compared with data obtained from batch fermentations and depended on the dilution rate applied. Maximum yields relative to consumed substrate were obtained with oleic acid at low dilution rate. It was found that during nitrogen limitation, lipase activity was suppressed. All carbon source mixtures tested allowed both cell growth and lipase production, but extra‐ and intracellular lipase activities were affected by the combination of substrates used. Maximum extracellular lipolytic productivity was attained with lactic and oleic acid mixtures, probably due to the non‐repressor effect of these carbon sources. The chemical composition of the biomass also depended on the type of substrate used and was related to the accumulation of lipidic compounds as intracellular inclusions, which were observed when oleic acid was used as the carbon source. The results obtained were compared with previous data from batch and fed‐batch cultures in order to select the best process strategies for the lipase production with C rugosa. The best lipase yields were obtained in fed‐batch fermentations using oleic acid. Copyright © 2003 Society of Chemical Industry
An improved model of association for VH–VL immunoglobulin domains: Asymmetries between VH and VL in the packing of some interface residues
Authors: Vargas‐Madrazo Enrique , Paz‐García Enrique
Published: June 2003

The antibody‐binding site is formed as a result of the association between VH and VL domains. Several studies have shown that this association plays an important role in the mechanism of antigen–antibody interaction (Stanfield et al. Structure 1: 83–93, 1993). Considering this, we propose that variations in the VH–VL association are part of the diversification strategy of the antibody repertoires. Previously, a model of association for VH–VL domains based on geometrical characteristics of the packing at the interface was developed by Chothia et al. (J. Mol. Biol. 186: 61–663, 1985). This model includes a common association form for antibodies and a three‐layer structure for the interface. In the present work, a complementary model is introduced to account for the general geometrical restrictions of the VH–VL interface, and particular arrangements related to the chemical properties or the side‐chain orientations of participating residues. Groups of residues assume common side‐chain orientations, which are apparently related to particular functions of different interface zones. Analyses of amino acid usage and network are in agreement with the side‐chain orientation patterns. Based on these observations, a three‐zone model has evolved to illuminate geometrical and functional restrictions acting over the VH–VL interface. Additionally, this study has revealed the asymmetrical relationships between VH and VL residues important for the association of the two domains. Copyright © 2003 John Wiley & Sons, Ltd.
Soil biochemical and chemical changes in relation to mature spruce (Picea abies) forest conversion and regeneration
Authors: Zhong Zheke , Makeschin Franz
Published: June 2003

To investigate soil changes from forest conversion and regeneration, soil net N mineralization, potential nitrification, microbial biomass N, L‐asparaginase, L‐glutaminase, and other chemical and biological properties were examined in three adjacent stands: mature pure and dense Norway spruce (Picea abies (L.) Karst) (110 yr) (stand I), mature Norway spruce mixed with young beech (Fagus sylvatica) (5 yr) (stand II), and young Norway spruce (16 yr) (stand III). The latter two stands were converted or regenerated from the mature Norway spruce stand as former. The studied soils were characterized as having a very low pH value (2.9 – 3.5 in 0.01 M CaCl2), a high total N content (1.06 – 1.94 %), a high metabolic quotient (qCO2) (6.7 – 16.9 g CO2 kg–1 h–1), a low microbial biomass N (1.1 – 3.3 % of total N, except LOf1 at stand III), and a relatively high net N mineralization (175 – 1213 mg N kg–1 in LOf1 and Of2, 4 weeks incubation). In the converted forest (stand II), C : N ratio and qCO2 values in the LOf1 layer decreased significantly, and base saturation and exchangeable Ca showed a somewhat increment in mineral soil. In the regenerated forest (stand III), the total N storage in the surface layers decreased by 30 %. The surface organic layers (LOf1, Of2) possessed a very high net N mineralization (1.5 – 3 times higher than those in other two stands), high microbial biomass (C, N), and high basal respiration and qCO2 values. Meanwhile, in the Oh layer, the base saturation and the exchangeable Ca decreased. All studied substrates showed little net nitrification after the first period of incubation (2 weeks). In the later period of incubation (7 – 11 weeks), a considerable amount of NO3‐N accumulated (20 – 100 % of total cumulative mineral N) in the soils from the two pure spruce stands (I, III). In contrast, there was almost no net NO3‐N accumulation in the soils from the converted mixed stand (II) indicating that there was a difference in microorganisms in the two types of forest ecosystems. Soil microbial biomass N, mineral N, net N mineralization, L‐asparaginase, and L‐glutaminase were correlated and associated with forest management.
Effect of distillery effluents on plant and soil enzymatic activities and groundnut quality
Authors: Singh Amar B. , Biswas Ashis K. , Ramana Sivakoti
Published: June 2003

A field experiment was conducted during the rainy season 2000 to examine the effect of distillery effluents, i.e., biomethanated spent wash (BSW), raw spent wash (RSW), and lagoon sludge (LS) versus recommended NPK+FYM (farmyard manure) on nutritional quality of groundnut (Arachis hypogaea L.) and enzyme activities of plant and soil. The distillery effluents did not affect the oil content (%), crude and true protein contents (%) in groundnut but increased the seed yield and the contents of methionine by 44 % (1.15 g (16 g N)–1 vs. 0.80 g (16 g N)–1 in control) and of cysteine by 24 % (1.36 g (16 g N)–1 vs. 1.10 g (16 g N)–1 in control). BSW produced the highest seed yield (619 kg ha–1) followed by RSW (557 kg ha–1) and LS (472 kg ha–1). LS recorded the highest total chlorophyll content (2.94 mg (g FW)–1) in groundnut leaves. Application of BSW and RSW significantly increased the activity of plant peroxidase whereas the plant polyphenol oxidase was higher in BSW only. The application of distillery effluents did not affect the nitrate reductase activity but BSW significantly increased the nitrate content in the rhizosphere soil. The three effluents significantly increased the dehydrogenase and alkaline phosphatase activity more than recommended NPK+FYM.
Geo‐Pedogenese mariner Rohmarschen Spiekeroogs
Authors: Giani Luise , Ahrens Vera , Duntze Oliver , Irmer Sven Kruse
Published: June 2003

Während für niedersächsische Rohmarschen im allgemeinen erhebliche Kalkvorräte charakteristisch sind, wurden auf Spiekeroog kalkfreie initiale Marschen gefunden. Ziel dieser Arbeit war es deshalb, die Marschböden Spiekeroogs vergleichend zu denen des Festlandes zu untersuchen und die Ursache des Fehlens von Carbonat zu klären, die im Zusammenspiel von Schwefel‐Dynamik und Sedimentationsverhalten vermutet wurde. Die Rohmarschen Spiekeroogs sind bezüglich ihres Bewuchses, vieler physikalischer Parameter und vor allem chemischer Eigenschaften (z. B. pH, Corg, Salinität, Feo, d, aK, KAK) vergleichbar mit denen der niedersächsischen Festlandsküste. Im Unterschied erstrecken sich die Rohmarschprofile Spiekeroogs über die gering mächtigen Marschensedimente und den darunter liegenden Sand, sind schluffreicher und tonärmer sowie carbonatärmer (0, 3 – 34, 5 g kg–1). Eine Kartierung wies kalkfreie Flächen aus. Die vergleichsweise moderate Schwefel‐Dynamik ist durch eine zeitlich und räumlich stabile SO4‐S‐Fraktion, im Mittel von 0, 3 – 0, 6 mg g–1 gekennzeichnet. Mit 1, 5 – 2, 9 mg g–1 ist auch die HNO3‐HCl‐S‐Fraktion eher stabil, während vor allem die HCl‐S‐Fraktion, bei großen Unterschieden zwischen den Standorten, in Korrelation mit sich ändernden Redoxpotenzialen einer zeitlichen Variabilität (monatlich HCl‐S‐Abnahmen bzw. Anstiege ∅︁ 0, 2 mg g–1) unterlag. Die vertikale Cs‐137‐Verteilung zeigte Peaks in 3 – 4 und 7 – 8 cm Bodentiefe und damit eine eher geringe Sedimentationsrate von 0, 2 – 0, 5 cm a–1. Die Ergebnisse haben gezeigt, dass die Schwefel‐Dynamik über längere Zeiträume zu erheblichen Kalkverlusten führt, die aufgrund der relativ geringen Sedimentationsrate und damit geringen Neuanlieferung von Carbonaten nicht ausgeglichen wird, so dass die Rohmarschen Spiekeroogs entkalkt in die terrestrische Bodenentwicklungsphase übergehen werden. Neben dem rezent üblichen Weg der Pedogenese der Kleimarschen über Roh‐ und Kalkmarschen gibt es den von Rohmarschen direkt zu Kleimarschen, der auch z. T. für heute alte Kleimarschen (Brackmarschen) Niedersachsens für möglich gehalten wird.
Loupes‐only microsurgery
Authors: Pieptu Dragos , Luchian Stefan
Published: June 2003

Standard magnification in microsurgery is accomplished with the operating microscope. Loupes are perceived by the microsurgical community as technically less safe. However, after several years of microscope‐only microsurgery, most of our microvascular procedures are performed under loupes 3.5–4×. Considering our results using loupes‐only microsurgery, which are comparable with those obtained when using the microscope, we suggest that loupe‐aided microsurgery might represent a natural progression for the experienced microsurgeon. Microsurgical skills and experience outweigh the importance of the magnification factor. While the microscope is mandatory for replantations distal to the palmary arch, microneurosurgery, and supramicrosurgery, loupes should be used in so‐called “macro‐microsurgery.” One may include in this category replantations down to the palmar arch and free flaps with vessels more than 1.5 mm, such as the latissimus, serratus, (para)scapular, fibula, radial forearm, rectus abdominis, dorsalis pedis, omentum, and jejunum. Before starting loupes‐only microsurgery, intensive training under the microscope is crucial. Less magnification does not mean less quality. © 2003 Wiley‐Liss, Inc. MICROSURGERY 23:181–188 2003
Vascular access in chronic dialysis: A plastic surgeon's approach
Authors: Pieptu Dragos , Luchian Stefan , Hriscu Mihaela , Mititiuc Irina , Florea Manuela , Romete Simona , Popa Maria , Ungureanu Angela , Chirita Loredana
Published: June 2003

Thirty‐five years after Brescia et al. (N Engl J Med 275:1089–1092, 1966) realized the first peripheral autogenous arteriovenous fistula, the “Achilles' heel” of chronic dialysis is still the absence of a good‐quality permanent vascular access. The number of patients depending on hemodialysis is increasing. Until 10 years ago, in Romania, there was a need to treat isolated critical cases. Nowadays, every dialysis center needs algorithms for a standardized approach, adaptable for each case. We reviewed 171 consecutive arteriovenous fistulas (132 patients) performed in adults in identical standard conditions: use of an inflatable tourniquet during the vascular dissection, microsurgical techniques, and use of only autogenous tissues. We analyzed our results, the technical difficulties encountered, and their management in long‐term follow‐up. The aim of this study was to set up the basic principles of our algorithms. Our approach, based on our education as plastic surgeons involved in hand surgery and microsurgery, might present the advantage of sparing renal patients vascular capital. © 2003 Wiley‐Liss, Inc. MICROSURGERY 23:226–232 2003
Synthesis and anti‐HIV activity of sulfated astragalus polysaccharide
Authors: Liu Guo‐Guang , Borjihan Gereltu , Baigude Huricha , Nakashima Hedeki , Uryu Toshiyuki
Published: June 2003

Sulfated astragalus polysaccharide (sulfated astragalan, SA) was prepared by chemical modification of astragalus polysaccharide abstracted from an astragalus menbranceus used as a Mongolia herbal medicine. Anti‐HIV activity of SA was assayed in vitro and the results indicated that the SA showing high anti‐HIV activity and lower cytotoxity. Sulfation of astragalan was carried out by using sulfur trioxide‐pyridine complex in a mixture of dimethylsulfoxide (DMSO) to give sulfated astragalan with degree of substitution (DS) of 1.14–1.20 and a number average molecular weight (Mn) of 1.27–1.46 × 104. Copyright © 2003 John Wiley & Sons, Ltd.
Synthesis and thermal degradation kinetics of cellulose esters
Authors: Sairam M. , Sreedhar B. , Mohan Rao D. V. , Palaniappan S.
Published: June 2003

Polymers that are biodegradable currently achieve high interest in material science since they offer reductions of landfill space during waste management as well as new end‐user benefits in various fields of applications. In this work, cellulose esters such as cellulose benzoate, cellulose succinate and cellulose cinnamate were prepared using dimethylaminopyridine along with dimethylaminopyridine‐p‐toluene sulfonic acid catalyst. Films of cellulose esters were cast from solution. Cellulose esters were characterized by spectral methods such as infrared, nuclear magnetic resonance, thermal method such as thermogravimetric analysis. Various methods of kinetic analysis were compared in the case of thermal degradation of the cellulose and cellulose esters. Copyright­© 2003 John Wiley & Sons, Ltd.
Cyclo‐depolymerization of poly(propylene terephthalate): some ring‐opening polymerizations of the cyclic oligomers produced
Authors: Kamau Stephen D. , Hodge Philip , Helliwell Madeleine
Published: June 2003

We report the cyclo‐depolymerization of poly(propylene terephthalate) to give a mixture of cyclic oligomers in 94% yield, the characterization of the mixture by 1H‐NMR spectroscopy, matrix assisted laser desorption ionization time of flight mass spectrometry and gel permeation chromatography. The major cyclic oligomer in the mixture was shown to be the cyclic dimer. It was isolated and its X‐ray crystal structure determined. Some entropically‐driven ring‐opening polymerizations of the cyclic oligomers were carried out. So too were some copolymerizations using mixtures of the cyclic oligomers and those derived similarly from poly(ethylene terephthalate) and poly(butylene terephthalate). 13C‐NMR spectroscopic analysis showed that the copolymers were random. Copyright © 2003 John Wiley & Sons, Ltd.
Factors influencing the fiberization and mechanical properties of polypropylene/polyamide 66 in situ composites
Authors: Huang Wen‐Yi , Shen Jing‐Wei , Chen Xiao‐Mei , Chen Hong‐Yan
Published: June 2003

In situ composites based on immiscible polypropylene (PP)–polyamide 66 (PA66) melt blends were prepared through extrusion, drawing, quenching and then injection molding. The results show that both draw ratio (λ) and compatibilizer content (Cg) have significant influences on the PA66 fiberization and mechanical properties of the composites. PA66 fiberization in the PP matrix is realized during the melt drawing through a die. The increase in λ is favorable for fiberization of the dispersed phase, which leads to a large increment of impact strength (ak) and some improvement of the tensile strength (σt) of the composites. Nevertheless, the elevated Cg is unfavorable for fiberization, which results in the reduction of ak whereas σt is enhanced, apparently due to the improvement of interfacial adhesion. The coalescence effect of PA66 droplets during drawing plays a key role in fiberization. The σt and ak of the composites are primarily dictated by the interfacial structure and fiber morphology, respectively, which determine the variation rules of these properties with λ or Cg. Copyright © 2003 Society of Chemical Industry
Investigation of pH sensitivity of poly(acrylic acid‐co‐acrylamide) hydrogel
Authors: Zhou Xianju , Weng Lihui , Chen Qiang , Zhang Jianming , Shen Deyan , Li Zhuchuan , Shao Manjun , Xu Jian
Published: June 2003

It was found that the upper critical solution temperature (UCST) of poly(acrylic acid‐co‐acrylamide) hydrogel decreases with increase in pH. The UCST of samples equilibrated in a buffer at pH 2.5 was 33.7 °C, whereas it shifted to below 0 °C when swollen in buffers above pH 10. FT‐IR showed that COOH group of acrylic acid ionized gradually in alkaline media. The morphology change of the hydrogel swollen in different buffers was studied by environmental scanning electron microscopy (ESEM). ESEM images showed that the pore size of the sample increased with increase in pH, and in strongly basic media the three‐dimensional network was replaced by a ‘sausage‐like’ or ‘desert‐like’ structure. A study of the pH‐dependent release of cefazolin sodium was also carried out. Copyright © 2003 Society of Chemical Industry
The effect of segment length on some properties of thermoplastic poly(ester–siloxane)s
Authors: Antic Vesna V , Govedarica Milutin N , Djonlagic Jasna
Published: June 2003

A series of novel thermoplastic elastomers, based on poly(dimethylsiloxane) (PDMS) as the soft segment and poly(butylene terephthalate) (PBT) as the hard segment, were synthesized by catalyzed two‐step, melt transesterification reactions of dimethyl terephthalate and methyl esters of carboxypropyl‐terminated poly(dimethylsiloxane)s (M̄n = 550–2170 g mol−1) with 1,4‐butanediol. The lengths of both the hard and soft segments were varied while the weight ratio of the hard to soft segments in the reaction mixture was maintained constant (57/43). The molecular structure, composition and molecular weights of the poly(ester–siloxane)s were examined by 1H NMR spectroscopy. The effectiveness of the incorporation of the methyl‐ester‐terminated poly(dimethylsiloxane)s into the copolymer chains was verified by chloroform extraction. The effect of the segment length on the transition temperatures (Tm and Tg) and the thermal and thermo‐oxidative degradation stability, as well as the degree of crystallinity and hardness properties of the synthesized TPESs, were studied. Copyright © 2003 Society of Chemical Industry
Miscibility windows in ternary polymer blends of a polyester, polymethacrylate and poly(styrene‐co‐acrylonitrile)
Authors: Su Chean‐Cheng , Lin Jiann‐Horng , Woo EM
Published: June 2003

Miscibility, phase diagrams and morphology of poly(ε‐caprolactone) (PCL)/poly(benzyl methacrylate) (PBzMA)/poly(styrene‐co‐acrylonitrile) (SAN) ternary blends were investigated by differential scanning calorimetry (DSC), optical microscopy (OM), and scanning electron microscopy (SEM). The miscibility window of PCL/PBzMA/SAN ternary blends is influenced by the acrylonitrile (AN) content in the SAN copolymers. At ambient temperature, the ternary polymer blend is completely miscible within a closed‐loop miscibility window. DSC showed only one glass transition temperature (Tg) for PCL/PBzMA/SAN‐17 and PCL/PBzMA/SAN‐25 ternary blends; furthermore, OM and SEM results showed that PCL/PBzMA/SAN‐17 and PCL/PBzMA/SAN‐25 were homogeneous for any composition of the ternary phase diagram. Hence, it demonstrated that miscibility exists for PCL/PBzMA/SAN‐17 and PCL/PBzMA/SAN‐25 ternary blends, but that the ternary system becomes phase‐separated outside these AN contents. Copyright © 2003 Society of Chemical Industry
Proteomic analysis of a lymphoma‐derived cell line (DG75) following treatment with a demethylating drug: Modification of membrane‐associated proteins
Authors: Poirier Florence , Joubert‐Caron Raymonde , Labas Valérie , Caron Michel
Published: June 2003

5’‐azacytidine (AZC) is a potent DNA demethylating agent used clinically for treatment of patients with malignant hemopathies. We have previously shown that AZC induces a halt in cell growth and a decrease of cell activity, without affecting cell viability. We have also shown using proteomics, that 35 polypeptides were differentially expressed in a cytoplasmic fraction. The aim of this study was to provide a more complete picture of modifications in AZC‐treated cells using cell membrane preparations. Therefore the protein pattern changes following AZC treatment of the cell line DG75 were studied on a detergent‐solubilized fraction obtained from these membranes. Results showed that 49 proteins were differentially expressed in the membrane fraction. Seven polypeptides were down‐regulated, while 42 were up‐regulated. The identity of most of these differentially expressed proteins was determined by mass spectrometry (liquid chromatography‐tandem mass spectrometry or matrix‐assisted laser desorption/ionization‐time of flight), and the identified proteins were grouped based on cellular function and participation in biochemical and signaling pathways.
Human bronchoalveolar lavage: Biofluid analysis with special emphasis on sample preparation
Authors: Plymoth Amelie , Löfdahl Claes‐Göran , Ekberg‐Jansson Ann , Dahlbäck Magnus , Lindberg Henrik , Fehniger Thomas E. , Marko‐Varga György
Published: June 2003

Respiratory diseases are an important health problem throughout the world. Whether caused by industrial pollutants, infections, smoking, cancer or metabolic diseases, damage to the lungs and airways often lead to morbidity or death. Bronchoalveolar lavage (BAL) obtained by fiber‐optic bronchoscopy is a biofluid mirroring the expression of normally secreted pulmonary proteins and the products of activated cells and destructive processes. The characterization of the proteome within this compartment provides an opportunity to establish temporal and prognostic indicators of airway disease. The objective of this study was to develop methods of analysis of BAL samples, which achieved the highest level of annotation of the expression map of this proteome. We have optimized the process of sample preparation after investigating a variety of techniques including dialysis, ultramembrane filtration, precipitation and gel filtration. We have further studied methods to remove albumin from BAL in order to unmask proteins hidden on two‐dimensional gels. In a pilot application of the method, BAL protein profiles obtained from healthy nonsmokers and smokers at risk for developing chronic obstructive pulmonary disease showed distinct differences.
Optimizing protein solubility for two‐dimensional gel electrophoresis analysis of human myocardium
Authors: Stanley Brian A. , Neverova Irina , Brown Heather A. , Van Eyk Jennifer E.
Published: June 2003

In order to maximize the myocardial proteome observed by two‐dimensional gel electrophoresis (2‐DE), the effect of (1) either an ionic or different zwitterionic detergents during tissue homogenization and (2) altering the “standard” detergent for isoelectric focusing (3‐[(3‐cholamidopropyl)dimethylamino]‐1‐propane sulfonate (CHAPS)) to either the zwitterionic detergent amidosulfobetaine‐14 (ASB‐14) or N‐decyl‐N‐N’‐dimethyl‐3‐ammonio‐1‐propane sulfonate (SB3‐10) was investigated. Sodium dodecyl sulfate was shown to be a superior detergent for extraction of proteins during homogenization of cardiac tissue compared to the detergents ASB‐14, SB3‐10 or CHAPS. Additionally, both ASB‐14 and SB3‐10 exhibited better extraction than CHAPS for distinct regions of two‐dimensional gels. In most cases, the best combination of homogenization and focusing conditions did not involve the use of the same detergent. Specifically, it was found that the ability to mix homogenization and focusing conditions can allow one to obtain an optimum balance between the resolution and number of protein spots obtained in 2‐DE analysis of cardiac tissue. An excellent initial combination of buffers to utilize for the general examination of cardiac proteins was determined to be initial homogenization in a buffer containing ASB‐14 followed by focusing in a buffer containing CHAPS.
Observation of multiple isoforms and specific proteolysis patterns of proliferating cell nuclear antigen in the context of cell cycle compartments and sample preparations
Authors: Naryzhny Stanislav N. , Lee Hoyun
Published: June 2003

The proliferating cell nuclear antigen (PCNA) is an essential component for eukaryotic chromosomal DNA replication and repair. PCNA forms a homotrimer ring, which may function as a DNA sliding clamp for DNA polymerases and, possibly, a docking station for other replication‐ and repair‐related proteins. Several reports have suggested the existence of different PCNA isoforms. Here we confirm, using high resolution two‐dimensional electrophoresis with narrow pH ranges, the existence of three PCNA isoforms in both Chinese hamster and human breast cancer cells. Among the three isoforms, M or main form is the dominant one throughout the cell cycle while the relative amounts of the minor components A (acidic) and B (basic) forms appear to vary during the cell cycle. We also observed that a specific pattern of PCNA proteolysis occurred during isoelectric focusing in spite of high urea (8 M) and detergent (2% 3‐[(3‐cholamidopropyl)dimethylamino]‐1‐propane sulfonate), which was largely inhibited by the proteosome inhibitor MG132 or boiling. Interestingly, the proteolysis pattern was mainly observed with samples isolated from cells in S and G2 phases. A similar but much lower level of PCNA proteolysis also occurred in vivo within the nuclei of the cells in S phase. Taken together, our data are consistent with the idea that the existence of the different isoforms and specific proteolysis of PCNA are relevant to its functions in vivo.
Proteome analysis of Escherichia coli W3110 expressing an heterologous sigma factor
Authors: Baglioni Paola , Bini Luca , Liberatori Sabrina , Pallini Vitaliano , Marri Laura
Published: June 2003

The recombinant plasmid pASK18 carries a Streptomyces DNA fragment which includes an open reading frame, designated psfS (putative sigma factor, Streptomyces), as its putative product showed a high degree of similarity with RNA polymerase sigma factors. Previous results showed that PsfS causes transcription initiation within the bgl operon promoter‐silencer region in Escherichia coli K12. In this study a proteomic approach has been applied in order to perform a comparative analysis of E. coli K12 W3110 wild‐type, W3110 (pASK18) and a W3110 Bgl+ spontaneous mutant. Either by qualitative or quantitative analysis, no significant difference was observed between the proteomes of W3110 and its Bgl+ derivative, while W3110 (pASK18) showed an altered profile by both analyses. Fourteen out of the 37 protein spots showing a different expression level in E. coli W3110 harboring pASK18 were identified by peptide mass fingerprinting. Among the proteins identified, thiol peroxidase (Tpx) was the only one up‐regulated. The possible involvement of bgl and tpx in the survival of the pathogen E. coli during infection is discussed.
Prediction of solvent effect on the reaction rate and endo/exo selectivity of a Diels–Alder reaction using molecular surface electrostatic potential
Authors: Gholami M. R. , Talebi B. A.
Published: June 2003

Molecular surface electrostatic potential was used to predict the solvent effect on the reaction rate, endo/exo selectivity and diastereomeric excess of a Diels–Alder reaction. It is shown that these quantities can be expressed in terms of molecular surface electrostatic potentials of solvents which are obtained computationally by the HF/6–31++G* procedure. Regression analyses and an experimental database are used to obtain analytical representation of rate constant, endo/exo selectivity and diastereomeric excess. The models obtained show that the hydrogen bond donor ability of solvents on the above mentioned properties is substantial, whereas solvophobicity only affects the reaction rate and endo/exo selectivity of the reaction. Copyright © 2003 John Wiley & Sons, Ltd.
Dissociation, tautomerism and electroreduction of xanthene and sulfonephthalein dyes inN,N‐dimethylformamide and other solvents
Authors: Mchedlov‐Petrossyan Nikolay O. , Kukhtik Valentina I. , Bezugliy Vasiliy D.
Published: June 2003

Protolytic equilibria in DMF of 10 dyes, fluorescein and its halogen derivatives, rhodamine B andN,N‐diethylrhodol, and of four sulfonephthaleins were studied by visible spectroscopy. The ratios of the stepwise dissociation constants of the substances in DMF, and the changes of these constants on transferring from water to DMF and other solvents, were explained taking into account the nature of functional groups and of the state of tautomeric equilibria. From the correlations between the Gibbs energies of tautomerization of the neutral species (quinonoid ⇌ colorless lactone) and the normalized Reichardt's parameter,$E_{\rm T}^{\rm N}$, the ‘limiting’ values of tautomerization constants of fluorescein and eosin at$E_{\rm T}^{\rm N} \rightarrow 0$(non‐polar aprotic media) were evaluated. The conversion of the neutral form of sulfonephthaleins into colorless sultones in DMF is demonstrated. The peculiarities of the reduction of the substances on a dropping mercury electrode in non‐aqueous media were revealed, namely the differentiating action of DMF in the first and second stages of electroreduction of the R2−anions. Copyright © 2003 John Wiley & Sons, Ltd.
Modulated‐temperature differential scanning calorimetry study of temperature‐induced mixing and demixing in poly(vinylmethylether)/water
Authors: Swier Steven , Van Durme Kurt , Van Mele Bruno
Published: June 2003

The heat capacity or reversing heat flow signal from modulated‐temperature differential scanning calorimetry can be used to measure the onset of phase separation in a poly(vinylmethylether)/water mixture, clearly showing the special type III lower critical solution temperature demixing behavior. Characteristic of this demixing behavior is a three‐phase region, which is detected in the nonreversing heat flow signal. Stepwise quasi‐isothermal measurements through the phase transition show large excess contributions in the (apparent) heat capacity signal, caused by demixing/remixing heat effects on the timescale of the modulation (fast process). These excess contributions and their time‐dependent evolutions (slow process) are useful in understanding the kinetics of phase separation and the morphology (interphase) development. Care has to be taken, however, in interpreting the heat capacity signal derived from the amplitude of the modulated heat flow because nonlinear effects lead to the occurrence of higher harmonics. Therefore, the raw heat flow signal for quasi‐isothermal demixing and remixing measurements is also examined in the time domain. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1824–1836, 2003
Fourier transform infrared studies of ionic interactions in perfluorinated acid copolymer blends
Authors: Tannenbaum R. , Rajagopalan M. , Eisenberg A.
Published: June 2003

Ionic interactions have been shown to enhance polymer–polymer miscibility in several highly dissimilar blend systems. In some cases, the miscibility is due to proton transfer from an acidic site on one polymer to a basic site on another, which leads to ion–ion interactions. Studies that have focused on the formation of ionomer blends from highly dissimilar materials, such as fluorocarbons and hydrocarbons or aromatics and aliphatics of widely differing glass transitions, have shown that in the absence of ionic interactions, these materials are immiscible. In this study, we have used Fourier transform infrared (FTIR) spectroscopy techniques, both qualitatively and semiquantitatively, to evaluate the extent of the proton‐transfer mechanism in the enhancement of miscibility in perfluorinated acid copolymer/poly(ethyl acrylate) blends. The perfluorinated acid copolymer contains sulfonic acid groups, whereas the poly(ethyl acrylate) has been modified by the introduction of various amounts of 4‐vinyl pyridine groups as comonomers in the polymer chains. The proton‐transfer mechanism in this case consists of the transfer of the proton on the sulfonic acid group to the nitrogen on the pyridine group, forming a pyridinium cation and a sulfonate anion pair. FTIR has been used to distinguish between the pyridine and pyridinium groups through their absorption bands at 1416 and 1642 cm−1, respectively. The relative intensities of these bands, as a function of the molar concentration of the pyridine comonomers in the blend, provides a direct quantitative indication of the extent of proton transfer occurring in the system. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1814–1823, 2003
Taking away the fear: A grounded theory study of cooperative care in the treatment of head and neck cancer
Authors: McLane Lani , Jones Katherine , Lydiatt William , Lydiatt Daniel , Richards Alan
Published: June 2003

Cooperative care is a relatively new treatment model that seeks to improve quality, conserve resources, and manage chronic conditions by providing patient and carepartner education in a homelike setting. Support from health care professionals is immediately available as patients and carepartners learn the skills needed to manage a disease and its treatment. This study sought to describe the effect of cooperative care on the treatment of head and neck cancer. Grounded theory methodology and focused interviews of 21 participants were used to answer three research questions: (1) Do the patients, carepartners, and providers involved in cooperative care perceive the potential psychosocial and self‐care benefits? (2) How does the cooperative care treatment model affect the achievement of self‐care for patients with surgical treatment of head and neck cancer? (3) What are appropriate theories regarding the benefits of cooperative care in the treatment of head and neck cancer that can be tested with quantitative methods? Results indicate that providers perceived cooperative care as a time‐consuming process that resulted in less anxious, more communicative patients who required fewer post‐discharge resources. Patients and carepartners perceived cooperative care as an experience that took away their fear by providing self‐care education within a caring community. Copyright © 2003 John Wiley & Sons, Ltd.
Do sociodemographic and disease‐related variables influence benefit‐finding in cancer patients?
Authors: Lechner Suzanne C. , Zakowski Sandra G. , Antoni Michael H. , Greenhawt Michael , Block Keith , Block Penny
Published: June 2003

This study examined patients' perceptions that having cancer led to positive life changes, or benefit‐finding (BF), e.g. improved relationships, enhanced appreciation of life, increased resilience and self‐reliance. We investigated the relations between BF, sociodemographic (e.g. gender, age, marital status, education, income) and disease‐related variables (e.g. severity of disease or cancer stage, time since diagnosis). The sample was comprised of 83 men and women with various types of cancer, and all 4 stages of disease were represented. Participants were most likely to be Caucasian (90%), married (66%) and well‐educated (68% partial college/specialized training). Of the demographic variables investigated, younger age was associated with greater BF scores. As hypothesized, BF also differed by stage of disease in a curvilinear fashion. Individuals with stage II disease had significantly higher BF scores than those with Stage IV or Stage I cancer. Time since diagnosis and treatment status (i.e. currently in treatment, completed treatment, no treatment) were not related to BF. Findings suggest that stage of disease is an important factor to consider when investigating positive perceptions of disease in individuals with cancer. Copyright © 2003 John Wiley & Sons, Ltd.
Inflammatory pulmonary nodules in Kawasaki disease
Authors: Freeman Alexandra F. , Crawford Susan E. , Finn Laura S. , López‐Andreu Juan A. , Ferrando‐Monleón Susana , Pérez‐Tamarit Desamparados , Cornwall Mona L. , Shulman Stanford T. , Rowley Anne H.
Published: June 2003

Symptomatic pulmonary manifestations of Kawasaki disease (KD) are uncommon. However, epidemiologic, radiologic, and histologic studies have indicated that respiratory symptoms and findings occur in KD and suggest that the KD agent may have a respiratory portal of entry. We report on three young infants with KD who developed pulmonary nodules, in addition to coronary artery aneurysms. Two patients had pathologic specimens available, one from biopsy and the other from autopsy. The nodules had predominantly mononuclear cell infiltrates, which were within the lung parenchyma and infiltrating vessel walls. Immunohistochemical studies of the nodules, using antibodies to common leukocyte antigen (LCA) and factor VIII‐related antigen, confirmed the inflammatory nature of the lesions and showed capillary proliferation. IgA plasma‐cell infiltration was observed in the nodule, consistent with previous KD findings of IgA plasma‐cell infiltration in the vessel walls, kidneys, pancreas, and upper respiratory tract. The two patients with nonfatal KD were treated with intravenous immunoglobulin and aspirin, with resolution of the nodules. We propose that when pulmonary involvement occurs in KD, it ranges from subclinical interstitial micronodular infiltrates to larger inflammatory pulmonary nodules. These pulmonary infiltrates and nodules likely reflect the host response to the etiologic agent of KD, and may resolve with the disease process. Recognition of this pulmonary complication of KD may enable cautious observation of such lesions for spontaneous resolution. Pediatr Pulmonol. 2003; 36:102–106. © 2003 Wiley‐Liss, Inc.
GMS solitons from vacuum string field theory
Authors: Bonora L. , Mamone D. , Salizzoni M.
Published: June 2003

We construct a set of tachyonic lumps in Vacuum String Field Theory that, in the presence of a background B field, give in the low energy limit exactly the complete sequence of noncommutative GMS solitons.