bluuebunny/crossref_metadata_2025 huggingface dataset:
The Retro–Diels–Alder Reaction PartI.CCDienophiles
Authors: Rickborn Bruce
Published: April 2004

The Diels–Alder (“DA”) reaction is so familiar to organic chemists that the retro‐Diels–Alder or retro‐diene reaction (hereafter “rDA”) requires no conceptual introduction. However, a working definition is needed to indicate the coverage of this review. The intent is to include all reported examples of the general skeletal process excluded in this chapter.

Any of the atoms in the starting material (cycloadduct) may be carbon or heteroatom, and substituents on all positions are allowed. In addition, any bond order available to the element in any oxidation state is included, as well as bonding to non‐nearest neighbor atoms (bicyclics, etc.).

The volume of literature required separation of this review into two parts. Part I covers all expelled C–C dienophiles, i.e. those reactions that generate a new carbon‐carbon double or triple bond in the dienophile that is formed. Part II, to appear later, covers those expelled dienophiles in which one or both atoms is a heteroatom.

Certain specific topics are intentionally omitted. These are: rDA reactions invoked under mass spectral conditions; rDA reactions of polymeric substrates; Electrocyclic processes, some of which are arguably very similar to rDA reactions (these are not addressed unless needed for clarification of an rDA sequence); and a thorough discussion of homo‐rDA reactions.

CAS‐Online searches resulted in ca. 1,300 references, of which ca. 900 proved pertinent to the rDA topic as defined and delimited above. Active literature searching was halted in April 1995, but occasional more recent articles are included.

Over 2,500 pertinent references were eventually found. Most were obtained by perusal of primary literature (articles) and secondary sources (books and reviews). Computer based search success was limited mainly by the failure of authors or abstractors to key‐word this topic, an especially common occurrence when the expelled dienophile was a simple substance such as N2or CO2. Overall, approximately 3,500 books, chapters, reviews, articles, and abstracts were consulted in an effort to make this review as comprehensive as possible. This was done with the certainty that some pertinent literature would be missed, tempered by the view that these omissions are probably also lost to any future rational search method.

Many secondary sources proved valuable not only for in‐depth discussion of certain rDA reaction types, but also for providing comparisons with related topics. To assist the reader, these secondary sources are referenced (alphabetically by first author within broad subject areas) with a title or brief note on the topic(s) addressed. The first group lists earlier reviews with primary focus on rDA reactions, followed by items of Historical/General Interest, reviews that deal with Experimental Methods, DA reactions (general and specific), reviews of Related Topics (these impinge in more or less significant ways on rDA reactions), and general treatments of Theory and Mechanism.
Aromatic Substitution by the SRN1 Reaction
Authors: Rossi Roberto A. , Pierini Adriana B. , Santiago Ana N.
Published: April 2004

The SRN1 (Unimolecular Radical Nucleophilic Substitution) is a process through which nucleophilic substitution is achieved on aromatic and aliphatic compounds that do not react or react slowly through polar nucleophilic mechanisms. This transformation takes place through electron transfer steps with radicals and radical anions as intermediates.

The SRN1 mechanism was proposed for the first time in 1966 for the substitution of alkyl halides with electron‐withdrawing groups and in 1970 for the substitution of unactivated aryl halides. Since then, the scope of the process has increased considerably, and it constitutes an important synthetic method for achieving the substitution of unactivated aromatic and heteroaromatic substrates, vinyl halides, perfluoroalkyl iodides, and activated and non‐activated alkyl compounds. Nucleophiles that can be used include anions derived from carbon or heteroatoms, which react to form a new carbon‐carbon or carbon‐heteroatom bond.

Several reviews have been published in relation to activated and non‐activated aliphatic SRN1 reactions, to aromatic photoinitiated reactions, to SRN1 reactions at aromatic centers, to reactions performed with electrochemical techniques, and to the synthetic applications of the process. This chapter attempts to cover aromatic SRN1 reactions including all the relevant literature up to the end of 1996.
Synthesis Of Nucleosides
Authors: Vorbrüggen Helmut , Ruh‐Pohlenz Carmen
Published: April 2004

This chapter deals with the synthesis of nucleosides (e.g., the formation ofN‐glycosides of sugars such asD‐ribose or 2‐deoxy‐D‐ribose with heterocyclic nitrogen bases). The methods of nucleoside synthesis have been treated in a number of reviews and monographs.

It is now generally accepted that nucleosides were among the first organic compounds formed at the start of evolution in the early history of our planet earth. To support this point, guanine and adenine were heated withD‐ribose in seawater, which contains the Lewis acid magnesium chloride as catalyst. One thus obtained the nucleosides guanosine and adenosine together with comparable yields of unnatural α‐nucleosides. The latter were gradually photoanomerized to the thermodynamically more stable compounds in overall yields of 5–6%. The furanose form of ribose reacts faster than the pyranose form.

Corresponding syntheses of the pyrimidine nucleosides uridine and cytidine from uracil , cytosine and ribose are more problematic and remain an enigma. The recent conversion of glycolaldehyde‐O‐phosphate and formaldehyde to ribose‐2,4‐di‐O‐phosphate might give new insights into the prebiotic syntheses of uridine and cytidine. The evidence and hypotheses for these prebiotic conversions and the evolution of RNA, as well as the implications of an “RNA World,” have been reviewed.

These RNA nucleosides are reduced in vivo as 5′‐O‐diphosphates by ribonucleotide reductases to the corresponding 2′‐deoxynucleosides—the building blocks of DNA such as 2′‐deoxyguanosine. The thermodynamically controlled synthesis of these four building blocks of RNA has implications for the design of efficient, high yielding, new methods for the synthesis of the naturally occurring nucleosides, nucleoside antibiotics, and modified nucleosides that may serve as antimetabolites to fight viral and parasitic diseases and cancer.

The nucleoside rings in this chapter are depicted arbitrarily in theanticonformation, as occurs predominantly in the crystal and solution (based primarily on NOE‐1H‐ and13C‐NMR measurements) forms of pyrimidine nucleosides. Only a few nucleosides, such as 6‐methyluridine, occur with the heterocyclic ring predominantly in thesynconformation.

The synthesis ofC‐nucleosides has been reviewed previously and is not covered in this review.
The Vilsmeier Reaction of Non‐Aromatic Compounds
Authors: Jones Gurnos , Stanforth Stephen P.
Published: April 2004

This chapter extends the discussion to reactions between the Vilsmeier‐Haack reagent (subsequently referred to as the Vilsmeier reagent for brevity) and any other compounds in which a carbon‐carbon bond is formed. The discussion thus excludes reactions in which the Vilsmeier reagent acts as a chlorinating agent (for example in the preparation of acid chlorides), or in which it forms carbon‐oxygen or carbon‐nitrogen bonds, unless these are accompanied by formation of a carbon‐carbon bond. For a discussion of the nature of the reagent and of the mechanism of the reaction, the earlier chapter in vol. 49 should be consulted. There are also a number of reviews that deal at length with mechanisms of reactions involving the Vilsmeier reagent, notably those by Jutz and Marson, and hence this chapter will concentrate on applications, with brief mention of mechanisms when necessary.

Wizinger has pointed out that alkenes could react with the Vilsmeier reagent, but his only examples were styrenes where the intermediate carbocation has considerable stability.

Hydrolysis gives the cinnamaldehyde. In principle, any alkene which is not too sterically hindered can undergo this reaction, but the Vilsmeier reagent has low reactivity as an electrophile, and in practice activation is often necessary. The addition depends on the HOMO of the alkene, and anything increasing the HOMO energy will aid reaction, as for example further conjugation (dienes, trienes, etc.) or the presence of an electron‐donating substituent. Hence aldehydes and ketones are active in their enol forms, and enol ethers and enamines are good substrates. Indeed, all additions covered by this chapter can be regarded as alkene additions, even those on active methyl groups attached to electron‐deficient rings. As with any reaction involving carbocation intermediates, rearrangements are possible; the initial products are sometimes enamines, and this can give rise to polysubstitution. The substrates are grouped into eleven major subsections; references to reviews of particular relevance will be found in the appropriate subsection.
The Ramberg‐Bäcklund Reaction
Authors: Taylor Richard J. K. , Casy Guy
Published: April 2004

The base‐mediated conversion of alpha‐halosulfones into region‐defined alkenes was first described by Ludwig Ramberg and Birger Backlund. This transformation has proved to be of wide synthetic value and is known as the Ramberg‐Backlund reaction (RBR). The facile nature of the RBR is surprising given the difficulties encountered when attempting to carry out nucleophilic substitution reactions on alpha‐halosulfones. In contrast to halogens adjacent to carbonyls and related electron‐withdrawing groups, polar, steric and field effects appear to combine leading to the marked deactivation of alpha‐halosulfones. The stereochemical outcome of the reaction was also unexpected: a predominance of Z‐alkenes is often observed with relatively weak bases, whereas stronger bases tend to favor E‐alkenes. The mechanism of the RBR was therefore the subject of intense interest, particularly in the 1950s and 1960s.

From the synthetic viewpoint, the RBR is attractive for a number of reasons, for example, the accessibility of the precursor sulfide and sulfones; the conjunctive nature of the process; the unambiguous location of the resulting double bonds, among others. Organic sulfones are readily available, but the preparation of alpha‐halosulfones can be problematic. In view of this, perhaps the most significant synthetic advance concerning RBR has been the development of Meyer's modification, which involves in‐situ halogenation‐RBR sequence and enables sulfones to be converted directly into alkenes.
This chapter discusses the mechanism of RBR, its scope and limitations, applications of the reaction in natural product synthesis, and comparison of the RBR with related procedures. Representative experimental procedures are also given.
Two scale high gain adaptive control
Authors: Polderman Jan Willem , Mareels Iven
Published: April 2004

Simple adaptive controllers based on high gain output feedback suffer a lack of robustness with respect to bounded disturbances. Existing modifications achieve boundedness of all solutions but introduce solutions that, even in the absence of disturbances, do not achieve regulation. In this paper a new modification that achieves the desired robustness without the side‐effect of undesirable solutions is proposed. The modification features two data‐driven stability indicators. Intuitively, the first indicator drives the ‘closed‐loop poles’ to the closed right half plane while the latter provides fine‐tuning that prevents persistent imaginary axis poles and their associated undesired behaviour. Copyright © 2004 John Wiley & Sons, Ltd.
Elevated plasma sVCAM‐1 levels in children with sickle cell disease: Impact of chronic transfusion therapy
Authors: Sakhalkar Vishwas S. , Rao Sreedhar P. , Weedon Jeremy , Miller Scott T.
Published: April 2004

Vascular cell adhesion molecule‐1 (VCAM‐1) has been implicated as being important in the pathophysiology of acute pain episodes (APE) and acute chest syndrome (ACS) of sickle cell disease (SCD). The frequency of these episodes is reduced by chronic transfusion therapy. The impact of chronic transfusion therapy on VCAM‐1 expression is unknown. Soluble VCAM‐1 (sVCAM‐1) levels were measured in plasma using an ELISA assay (R&D Systems) in 61 patients with SCD (age range 1.5–20 years) and 12 normal controls (2.5–14 years). SCD patients included 20 with ACS, 14 with APE, 12 at well‐child visits, and 15 receiving chronic transfusion therapy. Asymptomatic SCD patients had higher sVCAM‐1 levels compared to normal subjects (P < 0.001). Levels of sVCAM‐1 were further elevated during ACS (P < 0.001) and APE (P = 0.072) and returned to the asymptomatic range on resolution. Levels were significantly lower in transfused patients (P = 0.003) compared to asymptomatic SCD patients. Our findings of increased VCAM‐1 expression during ACS and perhaps APE offer a rationale for therapeutic use of cytokine and other VCAM‐1 modulators. The reduction of sVCAM‐1 levels observed in our transfused SCD patients offers insight into the mechanism of the protective effect of transfusion against ACS and APE and possibly stroke. Am. J. Hematol. 76:57–60, 2004. © 2004 Wiley‐Liss, Inc.
Embolization of intracranial aneurysms and sickle cell disease
Authors: Vicari Perla , Choairy Ana Cristina C. , Siufi Grazziella C. , Arantes Adriano M. , Fonseca José Roberto F. , Figueiredo Maria Stella
Published: April 2004

The association of intracranial aneurysms and sickle cell disease (SCD) has been described in the English‐language literature. Treatment strategies have included angiography and craniotomy. However, with advancement of non‐operative interventions, much controversy surrounds the treatment of these patients. Endovascular embolization has been used in many patients with cerebral aneurysms, but it had been reported in the literature in only two sickle cell patients. The authors present a case of endovascular embolization of multiple intracranial aneurysms in a patient with sickle cell anemia with good outcome. Am. J. Hematol. 76:83–84, 2004. © 2004 Wiley‐Liss, Inc.
Predictive value of QT dispersion for acute heart failure after autologous and allogeneic hematopoietic stem cell transplantation
Authors: Nakamae Hirohisa , Hino Masayuki , Akahori Mika , Terada Yoshiki , Yamane Takahisa , Ohta Kensuke , Hayashi Tomoshige , Tsumura Kei
Published: April 2004

The aim of our study was to evaluate whether corrected QT dispersion (QTc dispersion), an electrocardiographic marker, is a good predictor of the development of acute heart failure after high‐dose chemotherapy followed by autologous or allogeneic hematopoietic stem cell transplantation. We enrolled 50 consecutive patients, from age 15 to 63 years, with hematopoietic diseases scheduled to undergo autologous or allogeneic hematopoietic stem cell transplantation, and compared QTc dispersion with other markers before transplantation conditioning. In univariate logistic analysis, QTc dispersion was a significant factor for acute heart failure after hematopoietic stem cell transplantation (odds ratio, 3.7 per 10 msec; confidence interval, 1.6–8.5; P = 0.002). There were no significant differences as age, sex, systolic or diastolic echocardiographic function markers, cumulative anthracycline dose, or QTc before transplantation between patients with and without acute heart failure. After multiple adjustments for left ventricular ejection fraction, cumulative anthracycline dose, cyclophosphamide conditioning dose, QTc dispersion was a significant and independent factor for acute heart failure after hematopoietic stem cell transplantation (odds ratio, 48.0 per 10 msec; confidence interval, 1.4–1666.3; P = 0.03). This study demonstrated that QTc dispersion could be used as a powerful noninvasive predictor of the development of acute heart failure after hematopoietic stem cell transplantation. Am. J. Hematol. 76:1–7, 2004. © 2004 Wiley‐Liss, Inc.
Human herpesvirus 8 (HHV‐8)‐associated peritoneal primary effusion lymphoma (PEL) in two HIV‐negative elderly patients
Authors: Boulanger Emmanuelle , Hermine Olivier , Fermand Jean‐Paul , Radford‐Weiss Isabelle , Brousse Nicole , Meignin Véronique , Gessain Antoine
Published: April 2004

Human herpesvirus 8 (KSHV/HHV‐8) is associated with all forms of Kaposi sarcoma (KS), with a rare high‐grade B‐cell non‐Hodgkin lymphoma characterized by serous effusions in body cavities called primary effusion lymphoma (PEL) and with some forms of multicentric Castleman disease (MCD). Although mostly observed during AIDS, such disorders have also been described with a lower incidence in human immunodeficiency virus‐negative patients. We describe here the features of two novel cases of AIDS‐unrelated PEL. Two patients, a 78‐year‐old man (case 1) and a 86‐year‐old woman (case 2), both of French origin, presented exudative ascitic effusion containing numerous KSHV/HHV‐8+ EBV− large lymphomatous cells of B‐cell clonal origin, characterized by a CD45+ CD30+ CD19− CD20− immunophenotype. The PEL tumor cells harbored a homogenous and isolated trisomy 12 in case 1 and an aberrant expression of the T‐cell lineage antigen CD7 in case 2. Both patients were lymphopenic at the time of PEL diagnosis and rapidly died with progressive lymphoma. Moreover, patient 2 had a previous history of classic KS and MCD clinically improved after treatment with all‐trans‐retinoid acid and a concomitant metastatic breast adenocarcinoma. Compared to AIDS‐related PEL, these two cases displayed distinct features in particular the advanced age of patients, as observed for Mediterranean KS, and the absence of EBV coinfection. Am. J. Hematol. 76:88–91, 2004. © 2004 Wiley‐Liss, Inc.
MTHFR C677T polymorphism and its relation to ischemic stroke in the Black Sea Turkish population
Authors: Uçar Fahri , Sönmez Mehmet , Ovalı Ercüment , Özmenoǧlu Mehmet , Kartı S. Sami , Yılmaz Mustafa , Pakdemir Alper
Published: April 2004

The MTHFR C677T mutation has been shown to be associated with venous thrombosis. The role of this mutation in ischemic stroke is unclear. We investigated whether the MTHFR mutation is a risk factor for patients with ischemic stroke in the Black Sea Turkish population or not. We analyzed 30 patients (19 male, 11 female) [median age: 50 years (range: 28–78)] with ischemic stroke who had no known predisposition factors for stroke and 242 (182 male, 60 female) healthy controls [median age: 42 years (range: 18–65)]. Detection of the MTHFR C677T mutation was performed by using commercially available allele‐specific PCR‐ELISA kits. Prevalence of the MTHFR C677T genotype was 49.1% (CT, 45.8%; TT, 3.3%) in controls and 50% (CT, 43.3%; TT, 6.6%) in patients [OR: 1.03, 95% CI (0.45–2.35]). The prevalence of homozygous gene mutation for MTHFR was higher among patients with stroke than control subjects, but this difference was not statistically significant. The MTHFR gene mutation is not a risk factor for ischemic stroke formation in patients from the Black Sea region in Turkey. Am. J. Hematol. 76:40–43, 2004. © 2004 Wiley‐Liss, Inc.
Microgranular and t(11;17)/PLZF‐RARα variants of acute promyelocytic leukemia also present the flow cytometric pattern of CD13, CD34, and CD15 expression characteristic of PML‐RARα gene rearrangement
Authors: Rizzatti Edgar G. , Portieres Fernando L. , Martins Sérgio L.R. , Rego Eduardo M. , Zago Marco A. , Falcão Roberto P.
Published: April 2004

Acute promyelocytic leukemia (APL) is a subtype acute myeloid leukemia in which leukemic promyelocytes predominate in the bone marrow (BM). Rapid diagnosis is critical for treatment decision since all‐trans‐retinoic acid must be administrated promptly. The microgranular variant may be of difficult diagnosis, as it may be confused with other diseases on morphological grounds. The purpose of this study was to determine if the microgranular variant has the same antigenic profile as the classical hypergranular type. The immunophenotype of leukemic cells from the bone marrow of 50 patients, with the PML‐RARα gene rearrangement confirmed by RT‐PCR, was determined by flow cytometry using a large panel of 22 monoclonal antibodies and a polyclonal anti‐TdT antibody. Thirty‐four cases were classified as classical APL and 16 as microgranular APL. The immunophenotypic profile of the two subtypes was indistinguishable concerning the presence or absence of these antigens, including the absence of reactivity for the HLA‐DR antigen. The simultaneous immunophenotypic combination of a unique major cell population, heterogeneous intensity of expression of CD13, and the typical pattern of CD15/CD34 expression were similarly present in the hypergranular and microgranular subtypes. Homogeneous expression of CD33 was observed in 76% of the classical APL cases and in 100% of the microgranular cases. Additionally, we have studied two cases of PLZF‐RARα APL that also displayed the same immunophenotype described for classical APL. Thus, the immunophenotypic profile highly characteristic of the PML‐RARα gene rearrangement was also observed in microgranular and PLZF‐RARα variants of APL. Am. J. Hematol. 76:44–51, 2004. © 2004 Wiley‐Liss, Inc.
De novo complex chromosomal rearrangements (CCR) involving chromosome 1, 5, and 6 resulting in microdeletion for 6q14 in a female carrier with psychotic disorder
Authors: Lespinasse James , Bugge M. , Réthoré M.O. , North M.O. , Lundsteen C. , Kirchhoff M.
Published: April 2004

A 23‐year‐old obese woman with a psychotic disorder was found to have a de novo apparently balanced complex chromosomal rearrangement involving chromosomes 1, 5, and 6. Molecular cytogenetic analyses using high‐resolution comparative genomic hybridization (HR‐CGH) showed a microdeletion at 6q14 in a der(6). Application of HR‐CGH facilitated detection of micro‐rearrangement of all de novo apparently balanced complex chromosomal rearrangements (CCR) and supported the localization of the breakpoint. According to our knowledge, no constitutional interstitial microdeletion of chromosome 6q14 has been found associated with a schizoid‐type phenotype. © 2004 Wiley‐Liss, Inc.
Results of a genomewide linkage scan: Support for chromosomes 9 and 11 loci increasing risk for cigarette smoking
Authors: Gelernter Joel , Liu Xuexuan , Hesselbrock Victor , Page Grier P. , Goddard Andrew , Zhang Heping
Published: April 2004

Cigarette smoking is highly destructive to individuals and society, and is moderately heritable. We completed a genomewide linkage scan to map loci increasing risk for cigarette smoking in a set of families originally identified because they segregate panic disorder (PD). One hundred forty two genotyped individuals in a total of 12 families were studied (214 subjects analyzed, including non‐genotyped individuals). Of these individuals, 69 were “affected” with habitual cigarette smoking (i.e., they smoked more than one pack per day for at least a year, or at least 1/2 pack per day for at least 10 years), 49 were “unaffected” (i.e., they smoked less than 1/2 pack per day for less than 1 year), and 24 were scored as “unknown.” Nine families from the panic series were excluded from these analyses because they lacked multiple affected individuals with habitual cigarette smoking. In an initial genomewide scan, we genotyped a total of 416 markers (398 autosomal, 18 X‐chromosome) with an average spacing of less than 10 cM, spanning the genome. Linkage analysis (pairwise, or single‐point, and multi‐point) was performed using ALLEGRO. An additional 14 markers were genotyped in a high‐density panel to follow‐up on an identified region of interest on chromosome 11p. The three highest multi‐point Zlr scores (3.43, 3.04, and 3.01; P = 0.0003, P = 0.0012, and P = 0.0013, respectively), which each reflect “suggestive” evidence for linkage, were observed in multi‐point linkage analyses using Allegro on chromosomes 11p and 9, near markers D11S4046, D9S283, and D9S1677, respectively. D11S4046 is in a region where linkage to alcohol dependence and linkage disequilibrium to substance dependence have previously been identified. The chromosome 9 region we identified as possibly linked to cigarette smoking in anxiety families, was previously identified as significantly linked to PD in Icelandic pedigrees. We also identified evidence supporting linkage (Zlr score > 2.3, P < 0.01) to regions of chromosomes 14, 16, and X. There was a significant phenotypic association between PD and cigarette smoking (P < 0.001). Conclusions: We identified evidence for two loci increasing risk for cigarette smoking that map to chromosomes 9 and 11. There is now evidence supporting linkage or association of chromosome 11 markers with alcohol dependence, illegal drug abuse and dependence, and cigarette smoking. Interestingly, one of our most promising linkage regions, includes a region previously identified as linked to PD. © 2004 Wiley‐Liss, Inc.
Funktionale poröse Koordinationspolymere
Authors: Kitagawa Susumu , Kitaura Ryo , Noro Shin‐ichiro
Published: April 2004

Die Chemie der Koordinationspolymere hat sich in den vergangenen Jahren rasant entwickelt. Strukturen aus einer Vielzahl molekularer Bausteine mit unterschiedlichen Wechselwirkungen sind mittlerweile zugänglich. Die nächste Stufe ist die chemische und physikalische Funktionalisierung dieser Architekturen durch Einstellung ihrer Porositäten. Dieser Aufsatz konzentriert sich auf drei Aspekte von Koordinationspolymeren: 1) Anwendung von Kristall‐Engineering zum Aufbau poröser Gerüste aus Konnektoren und Linkern (“Nanospace‐Engineering”), 2) Charakterisierung und Katalogisierung porös‐struktureller Funktionalität für Anwendungen in Speicherungs‐, Austausch‐, Trennprozessen etc. und 3) porös‐strukturelle Funktionalität auf der Basis dynamischer Kristallumwandlungen durch Gastmoleküle oder physikalische Reize. Ziel ist es, den aktuellen Stand der Forschung zur Chemie und Physik von und in den Mikroporen poröser Koordinationspolymere vorzustellen.
Effect of the temperature on the friction‐wear properties of poly(ether ketone) with a cardo group
Authors: Tian Nong , Yan Fengyuan , Liu Weimin
Published: April 2004

We studied the effect of temperature on the friction‐wear properties of poly(ether ketone) with a cardo group (PEK‐C) with a XuanWu‐3 pin‐disc friction‐and‐wear tester. Testing conditions such as the temperature obviously affected the friction and wear behavior of PEK‐C. As the ambient temperature increased, the wear of PEK‐C increased, and there was a maximum value of the friction coefficient of PEK‐C at a certain temperature. This phenomenon could be attributed to the effect of an adhesive–elastic property of PEK‐C. Scanning electron microscopy revealed that the size and shape of the wear debris of PEK‐C varied as the temperature varied. The main mechanism behind the different tribological characteristics lay in the variations of the physical state on the friction surface of PEK‐C due to the increasing surface temperature of PEK‐C. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 696–699, 2004
Synthesis and characterization of a high oil‐absorbing magnetic composite material
Authors: Li Peixun , Yu Bo , Wei Xiucheng
Published: April 2004

The high oil magnetic composite resin, which is a low crosslinking resin, was synthesized by conventional suspension copolymerization in the present work. The effect of the monomer ratio, crosslinker, initiator, modified Fe3O4, and reaction time on oil absorptivity of the resin and defined optimum reaction condition were studied. The highest oil absorptivity of the resin was about 20 g/g in chloroform and 10.5 g/g in toluene when the extent of modified Fe3O4 was 5%. Infrared (IR), X‐ray diffractometer (XRD), synthetic themoanalyzer, laser particle size analyzer, and vibrating‐sample magnetometer (VSM) were used to study the properties of the oil‐absorbing magnetic composite resin. The magnetic composite resin can be recovered after conveniently and rapidly absorbing oil by magnetic separation techniques without excluding other mechanical techniques. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 894–900, 2004
Synthesis and properties of polymeric biocides based on poly(ethylene‐co‐vinyl alcohol)
Authors: Park Eun‐Soo , Kim Hye Kyung , Shim Jae Hun , Kim Mal‐Nam , Yoon Jin‐San
Published: April 2004

Poly(ethylene‐co‐vinyl acetate) with 55 wt % vinyl acetate units (EVA55) was cryogenically ground and saponified in KOH/ethanol solution to obtain poly(ethylene‐co‐vinyl alcohol) (EVOH55). Polymeric antimicrobial agents were synthesized by reacting three antimicrobial agents, 4‐aminobenzoic acid (ABA), salicylic acid (SA), and 4‐hydroxy benzoic acid (HBA) with EVOH55. The polymers became more flexible and exhibited lower melting peak temperature and heat of fusion as the content of the chemically bound ABA, SA, and HBA units increased. These phenomena appeared more significant in the order of ABA < HBA < SA. S. aureus, Gram‐positive bacterium, was more susceptible to the polymeric antimicrobial agents than P. aeruginesa, Gram‐positive bacterium. The antimicrobial activity increased in the order of EVOH55‐HBA < EVOH55‐ABA < EVOH‐SA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 765–770, 2004
Fabrication and amplification of Rhodamine B‐doped step‐index polymer optical fiber
Authors: Liang Hao , Zheng Zhiqiang , Li Zengchang , Xu Jie , Chen Biao , Zhao Hui , Zhang Qijin , Ming Hai
Published: April 2004

A step‐index polymer optical fiber (SI POF) containing Rhodamine B in poly(methyl methacrylate) (PMMA) has been fabricated by a preform technique. Fluorescence of different fiber lengths were observed and discussed. A high gain (23 dB) for a SI POF with 60‐cm length, 400‐μm diameter was obtained. The Rhodamine B content of the doped SI POF is 5 ppm‐wt. The signal wavelength providing the highest gain for a 60 cm SI POF is around 630 nm, and the optimum fiber length is about 60 cm at 10 kW launched pump power. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 681–685, 2004
Positioning theory and the negotiation of information needs in a clinical midwifery setting
Authors: McKenzie Pamela J.
Published: April 2004

Studies of everyday life information seeking have begun to attend to incidental forms of information behavior, and this more inclusive understanding of information seeking within broader social practices invites a constructionist analytical paradigm. Positioning theory is a constructionist framework that has proven useful for studying the ways in which interactional practices contribute to information seeking. Positions can construct individuals or groups of people in ways that have real effects on their information seeking. This article identifies some specific types of discursive positioning and shows how participants in a clinical care setting position themselves and one another in ways that justify different forms of information seeking and giving. Examples are drawn from an ongoing study of information seeking in prenatal midwifery encounters. The data consist of audio recordings of nine prenatal midwifery visits and of 18 follow‐up interviews, one with each participating midwife and pregnant woman. The midwifery model of care is based on a relationship in which the midwife provides the pregnant woman with information and support necessary for making informed decisions about her care. Midwife–client interactions are therefore an ideal context for studying information seeking and giving in a clinical encounter.
Clearance of minute virus of mice by flocculation and microfiltration
Authors: Wickramasinghe S.Ranil , Han Binbing , Carlson Jonathan O. , Powers Scott M.
Published: April 2004

Clearance of minute virus of mice (MVM) from CHO cell suspensions by flocculation and microfiltration has been investigated. MVM is a parvovirus that is recommended by the U.S. Food and Drug Administration for validating clearance of parvoviruses. The feed streams were flocculated using a cationic polyelectrolyte. Virus clearance in excess of 10,000‐fold was obtained in the bulk permeate for flocculated feeds streams. However, the level of clearance was only about 10‐ to 100‐fold for unflocculated feed streams. The results suggest that virus clearance involves interactions between the MVM particles, the cationic polyelectrolyte, and the CHO cells present. Validating virus clearance is a major concern in the biotechnology industry. New unit operations are frequently added to the purification train simply to validate virus clearance. However, many of these unit operations are less effective at validating clearance of nonenveloped viruses. Validating clearance of parvoviruses is often particularly problematic as they are nonenveloped and the virus particles are small (18 to 24 nm), making physical removal difficult. The results obtained herein indicate that addition of the cationic polyelectrolyte not only results in significant clearance of MVM but also leads to an increase in permeate flux. © 2004 Wiley Periodicals, Inc.
SKED: A course scheduling and advising software
Authors: Mihali Raul , Sobh Tarek , Vamoser Damir
Published: April 2004

This article presents a software application that can solve the problem of course scheduling and advising. The employed algorithms offer optimal course scheduling outputs for any given set of courses and requirements, as well as allowing for customizations by advisors or students. If the correct set of requirements and departmental courses has been set, the results of the application can be directly used for registration purposes. The proposed software is thus capable of saving hours of time for advising faculty. Once the school specific data and requirements have been set, for any specific student information, the application will search and output the schedules that will allow the student to graduate fastest and in the least number of semesters/quarters possible. Depending on the factors and data considered, the execution time varies from a few seconds to a few minutes. Currently, we have successfully tested and implemented the application at the University of Bridgeport, CT. © 2004 Wiley Periodicals, Inc. Comput Appl Eng Educ 12: 1–19, 2004; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.10054
Virtual laboratory: A distributed collaborative environment
Authors: Achalakul Tiranee , Sirinaovakul Booncharoen , Nuttaworakul Nion
Published: April 2004

This article proposes the design framework of a distributed, real‐time collaborative architecture. The architecture concept allows information to be fused, disseminated, and interpreted collaboratively among researchers who live across continents in real‐time. The architecture is designed based on the distributed object technology, DCOM. In our framework, every module can be viewed as an object. Each of these objects communicates and passes data with one another via a set of interfaces and connection points. We constructed the virtual laboratory based on the proposed architecture. The laboratory allows multiple analysts to collaboratively work through a standard web‐browser using a set of tools, namely, chat, whiteboard, audio/video exchange, file transfer and application sharing. Several existing technologies are integrated to provide collaborative functions, such as NetMeeting. Finally, the virtual laboratory quality evaluation is described with an example application of remote collaboration in satellite image fusion and analysis. © 2004 Wiley Periodicals, Inc. Comput Appl Eng Educ 12: 44–53, 2004; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20008
Heterogeneity of Gleason grade in multifocal adenocarcinoma of the prostate
Authors: Arora Rebecca , Koch Michael O. , Eble John N. , Ulbright Thomas M. , Li Lang , Cheng Liang
Published: April 2004

BACKGROUND

The Gleason grading system uniquely combines data from different areas of carcinoma in the same prostate specimen. Prostatic adenocarcinoma often is multifocal, and different Gleason grades may be present in different foci. The current study was undertaken to compare the Gleason grades of individual adenocarcinoma foci in a given specimen with the overall Gleason grades (primary and secondary) of that specimen.

METHODS

Data were obtained from 115 consecutive radical prostatectomy specimens via whole‐mount processing and complete sectioning. Diagrams were constructed by tracing the outline of each whole‐mount section, and tumor maps subsequently were generated. The largest focus was considered the index tumor. Each prostatectomy specimen was assigned primary and secondary Gleason grades, and each tumor focus was assigned its own primary and secondary Gleason grades. Tumor volume was measured using the grid method.

RESULTS

Two or more adenocarcinoma foci were present in 87% of all specimens (2 foci, n = 20; 3 foci, n = 33; 4 foci, n = 17; 5 foci, n = 13; > 5 foci, n = 17). Specimens (n = 15) containing a single tumor were excluded from further analysis. Among the remaining specimens (n = 100), all tumor foci had Gleason grades that were the same as the corresponding overall Gleason grades in only 9 cases (9%). The Gleason score (i.e., the sum of the primary and secondary grades) of the index tumor was correlated with the overall Gleason score in 68% of specimens. The primary grade of the index tumor was the same as the overall primary grade in 97 specimens, whereas the secondary grade of the index tumor was the same as the overall secondary grade in only 68 specimens. The primary and secondary grades of the index tumor, compared with the overall Gleason primary and secondary grades, were reversed in 17 specimens.

CONCLUSIONS

The findings of the current study demonstrated the histologic heterogeneity of multifocal prostate malignancies. Although the Gleason grading system was used to determine an overall score for prostate carcinoma within a specimen, the scores of individual tumors, including index tumors, often did not agree with this overall score. These findings may have implications with respect to future biomarker and tissue array studies. Cancer 2004. © 2004 American Cancer Society.
Assessment of procalcitonin as a diagnostic and prognostic marker in patients with solid tumors and febrile neutropenia
Authors: Jimeno Antonio , García‐Velasco Adelaida , del Val Olga , González‐Billalabeitia Enrique , Hernando Susana , Hernández Rosario , Sánchez‐Muñoz Alfonso , López‐Martín Ana , Durán Ignacio , Robles Luis , Cortés‐Funes Hernán , Paz‐Ares Luis
Published: April 2004

BACKGROUND

Cancer patients with fever and neutropenia currently are assessed on clinical grounds only. The current study prospectively evaluated the efficacy of baseline procalcitonin (PCT) in the detection of bacteremia and in the prediction of outcome in patients with solid tumors and febrile neutropenia.

METHODS

PCT levels were determined at baseline and every 48 hours in 104 patients undergoing chemotherapy who developed fever (axillary temperature > 38 °C on 2 occasions or > 38.3 °C in a single record) and neutropenia (absolute neutrophil count < 500 cells/μL).

RESULTS

The median baseline PCT values were significantly higher in patients who had microbiologically documented infections (1.24 ng/mL) compared with patients who had clinically documented infections (0.27 ng/mL) or fever of unknown origin (0.21 ng/mL; P < 0.01). Accordingly, a PCT cut‐off value of 0.5 ng/mL was reached more frequently in patients who had microbiologically documented infections compared with patients who had clinically documented infections or fever of unknown origin (66.7% vs. 13.4%, respectively; P < 0.001). Furthermore, this threshold also was associated with an increased likelihood of treatment failure (70.0% vs. 14.9%; P < 0.001). All 4 septic patients and all 5 patients who ultimately died presented PCT values 5‐fold to 10‐fold greater than the median values. Clinical evaluation in combination with baseline PCT assessment appeared to improve clinical risk evaluation alone.

CONCLUSIONS

Baseline PCT levels were higher in patients who had febrile neutropenia with bacteremia compared with patients who had clinical infections or fever of unknown origin. PCT helped to identify patients who had microbiologic infections and patients who were at high risk of treatment failure, and PCT may constitute a complementary tool in the initial assessment of such patients. Cancer 2004. © 2004 American Cancer Society.
Cytoarchitectonic and connectional organization of the ventral lateral geniculate nucleus in the cat
Authors: Nakamura Hiroyuki , Itoh Kazuo
Published: April 2004

The ventral lateral geniculate nucleus is a small extrageniculate visual structure that has a complex cytoarchitecture and diverse connections. In addition to small‐celled medial and lateral divisions, we cytoarchitectonically defined a small‐celled dorsal division. A large‐celled intermediate division intercalated between the three small‐celled divisions, which we divided into medial and lateral intermediate subdivisions. In WGA‐HRP injection experiments, the different cytoarchitectonic divisions were shown to have connections with different nuclei. The medial division was reciprocally connected to the pretectum and projected to the superficial layers of the superior colliculus and the intralaminar nuclei. The medial intermediate division received projections from the intermediate layer of the superior colliculus and the lateral and interpositus posterior cerebellar nuclei, and projected to the intermediate layer of the superior colliculus, the periaqueductal gray of midbrain, and the intralaminar nuclei. The lateral intermediate divisions received projections from the pretectum, the intermediate layer of the superior colliculus, and the lateral and interpositus posterior cerebellar nuclei, and projected to the pretectum, superficial layers of the superior colliculus, and the pulvinar. The lateral division received projections from superficial layers of the superior colliculus and had reciprocal connections with the pretectum. The dorsal division received projections from the pretectum and had reciprocal connections with the periaqueductal gray of midbrain. The different cytoarchitectonic divisions of the ventral lateral geniculate nucleus are thus suggested to play different functional roles related to vision, eye and head movements, attention, and defensive reactions. J. Comp. Neurol. 473:439–462, 2004. © 2004 Wiley‐Liss, Inc.
Multiscale variety in complex systems
Authors: Bar‐Yam Yaneer
Published: April 2004

The Law of Requisite Variety is a mathematical theorem relating the number of control states of a system to the number of variations in control that is necessary for effective response. The Law of Requisite Variety does not consider the components of a system and how they must act together to respond effectively. Here we consider the additional requirement of scale of response and the effect of coordinated versus uncoordinated response as a key attribute of complex systems. The components of a system perform a task, with a number of such components needed to act in concert to perform subtasks. We apply the resulting generalization—a Multiscale Law of Requisite Variety—to understanding effective function of complex biological and social systems. This allows us to formalize an understanding of the limitations of hierarchical control structures and the inadequacy of central control and planning in the solution of many complex social problems and the functioning of complex social organizations, e.g., the military, healthcare, and education systems. © 2004 Wiley Periodicals, Inc. Complexity 9: 37–45, 2004
Preliminary Results of Modelling Changes of Edge Plasma Transport due to the Presence of TEXTOR‐DED
Authors: Gerhauser H. , Zagórski R.
Published: April 2004

We use the 2D multifluid code TECXY to model possible changes of edge plasma transport in the vicinity of the dynamic ergodic divertor (DED) of TEXTOR tokamak. The increased effective radial transport coefficients in the stochastic magnetic field are calculated according to Tokar's model of optimal paths. A parameter study is carried out in order to estimate the possible changes of Marfe onset, position and strength by the action of DED. In the presence of carbon we do not find Marfe stabilization by DED transport. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Kinetic modelling of dusty plasmas
Authors: Matyash K. , Schneider R.
Published: April 2004

Modelling of ECR‐heated methane plasmas was done using a particle‐in‐cell code with collisions (PIC MCC) to get a better understanding in the problem of carbon layer production and chemical sputtering in such plasmas, which serve as a model system of divertor plasmas being dominated by carbon sputtering, especially at detached conditions. A fully kinetic model (PICMCC, resolving also the sheath in front of the wall) including all relevant species and their reactions (neutrals, ions, electrons) was developed and applied. The same model was used to study capacitive RF discharges which are also used to create so‐called plasma crystals. Depending on neutral gas pressure different plasma conditions appear (determined by the importance of collisions with neutrals). For low neutral densities rather dynamic plasma profiles and distribution function emerge (stochastic Fermi heating), whereas for high densities quasi‐stationary conditions show up. These are then used for the study of plasma crystals, where the dust particles are introduced as additional species in the model.

The creation mechanism of these quasi‐ordered systems are discussed (force balance between gravitational force and electrostatic electric field force in the sheath) with special emphasis of the ion‐dust interaction (ion drag force) establishing also dust molecules through focussing of ion flows in the sheath regions of such discharges. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of resistive drift wave turbulence on tokamak edge transport
Authors: Nishimura Y. , Borrass K. , Coster D. , Scott B.
Published: April 2004

Tokamak edge plasma transport in a diverted geometry is studied employing Braginskii type two dimensional transport simulation and drift wave turbulence simulation. The two models are connected through local perpendicular transport coefficients. The basic idea behind is to replace fast time scale, repetitive turbulence vortex dynamics by a diffusion operator. To this end, parameterization of transport coefficients D and χ is introduced. The transport is determined by the gradient drives inside the separatrix and non‐adiabatic electron response induced by high collisionality in the low temperature open‐magnetic‐field‐line regions. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Virus‐specific CD8+ T lymphocytes within the normal human liver
Authors: Ward Scott M. , Jonsson Julie R. , Sierro Sophie , Clouston Andrew D. , Lucas Michaela , Vargas Ana L. , Powell Elizabeth E. , Klenerman Paul
Published: April 2004

The frequency and phenotype of human antiviral memory CD8+ T cells in blood are well studied, yet little is known about their distribution within tissues. Analysis of antiviral CD8+ T cell populations derived from a unique set of normal liver and blood samples identified a consistent population of virus‐specific cells within the liver. In comparison to the circulating T cells, the liver‐derived T cells were present at frequencies which were variably enriched compared to that in the blood, and showed significant differences with regard to the expression of CD45RA, CD45RO, CD95, CCR7, CD27 and CD28. The differences in these cell surface markers are consistent with a mature ‘effector memory’ phenotype of antigen‐specific CD8+ T cells within the liver. An enrichment of an activated subset of NKT cells (Vα 24/Vβ 11) was also observed, a finding which may be relevant to the regulation of the antiviral populations.