bluuebunny/crossref_metadata_2025 huggingface dataset:
Tumor flare reaction associated with lenalidomide treatment in patients with chronic lymphocytic leukemia predicts clinical response
Authors: Chanan‐Khan Asher , Miller Kena C. , Lawrence David , Padmanabhan Swaminathan , Miller Austin , Hernandez‐Illatazurri Francisco , Czuczman Myron S. , Wallace Paul K. , Zeldis Jerome B. , Lee Kelvin
Published: November 2010

BACKGROUND:

In patients with chronic lymphocytic leukemia (CLL), treatment with lenalidomide induces a unique, previously uncharacterized, immune response called tumor flare reaction (TFR). The clinical significance of this reaction remains unknown.

METHODS:

Forty‐five patients with CLL who were treated with lenalidomide in a phase 2 clinical trial were evaluated for the clinical features, intensity, and duration of TFR. Correlation was made with tumor response and the immune cellular microenvironment. Steroids for the prophylaxis of TFR was not given to patients in Group A (n = 29) whereas patients in Group B (n = 16) received low‐dose prednisone as well as a slow dose escalation of lenalidomide for the prevention of TFR.

RESULTS:

Thirty (67%) patients experienced a TFR, with a grade 2 or 3 reaction (according to National Cancer Institute Common Toxicity Criteria [version 3.0]) observed in 33% of patients (47% in Group A and 9% in Group B; P = .05). The median time to onset of the TFR was 6 days, and was longer in the patients receiving prophylaxis (4 days vs 9 days, respectively; P = .01). A complete response was observed in 7 of 30 (23%) patients with TFR and 1 of 15 (7%) patients without TFR. The median progression‐free survival was 19.9 months and 19.4 months, respectively, for patients with versus those without TFR (P = .92).

CONCLUSIONS:

TFR is a unique immune‐mediated phenomenon noted with lenalidomide treatment only in patients with CLL that correlates with clinical response. It can be effectively managed with anti‐inflammatory agents. Cancer 2011. © 2010 American Cancer Society.
Overtreatment of men with low‐risk prostate cancer and significant comorbidity
Authors: Daskivich Timothy J. , Chamie Karim , Kwan Lorna , Labo Jessica , Palvolgyi Roland , Dash Atreya , Greenfield Sheldon , Litwin Mark S.
Published: November 2010

BACKGROUND:

Men with low‐risk prostate cancer and significant comorbidity are susceptible to overtreatment. The authors sought to compare the impact of comorbidity and age on treatment choice in men with low‐risk disease.

METHODS:

The authors sampled 509 men with low‐risk prostate cancer diagnosed at the Greater Los Angeles and Long Beach Veterans Affairs Medical Centers between 1997 and 2004. Rates of aggressive treatment (radical prostatectomy, radiation therapy, brachytherapy) were determined among men of different ages and with different Charlson comorbidity scores. Multivariate modeling was used to determine the influence of both variables in predicting nonaggressive treatment, and Cox proportional hazards analysis was used to compare the risk of other‐cause mortality among groups according to Charlson score and age.

RESULTS:

Men with Charlson scores ≥3 were treated aggressively in 54% of cases (30 of 56 men), while men aged >75 years at diagnosis were treated aggressively in 16% of cases (7 of 44 men). In multivariate analysis, age >75 years was a much stronger predictor of nonaggressive treatment (relative risk, 12.0; 95% confidence interval [CI], 5.4‐28.3) than a Charlson score ≥3 (relative risk, 2.0; 95% CI, 1.3‐2.9). In survival analysis, men with Charlson scores ≥3 had an 8‐fold increased risk (hazard ratio, 8.4; 95% CI, 4.2‐16.6) and 70% probability of other‐cause mortality at 10 years, whereas age >75 years was associated with a 5‐fold increased risk (hazard ratio, 4.9; 95%CI, 1.7‐13.8) and a 24% probability of other‐cause mortality.

CONCLUSIONS:

Men with significant comorbidity often were overtreated for low‐risk prostate cancer. Like advanced age, significant comorbidity should be a strong relative contraindication to aggressive treatment in men with low‐risk disease. Cancer 2011. © 2010 American Cancer Society.
Country of birth, socioeconomic factors, and risk factor control in patients with type 2 diabetes: a Swedish study from 25 primary health‐care centres
Authors: Sundquist Kristina , Chaikiat Åsa , León Vania Ramírez , Johansson Sven‐Erik , Sundquist Jan
Published: November 2010

Background

Few large‐scale studies have examined the association between sociodemographic factors and the probability of reaching the recommended levels of haemoglobin A1c (HbA$_{\rm{1c}}$) and blood lipids in patients with type 2 diabetes. The aim was to investigate whether sociodemographic characteristics of patients with type 2 diabetes affected the odds that they would reach recommended levels of blood lipids and HbA$_{\rm{1c}}$.

Methods

This study included 2912 men and 2136 women, in the age group of 35‐74, with diagnosed type 2 diabetes from 25 primary health‐care centres in Stockholm, Sweden. National population registers were linked to clinical data from electronic records and logistic regression was used to estimate odds ratios.

Results

Less than half of the men and women with diabetes reached the recommended levels of HbA$_{\rm{1c}}$. Even fewer reached the recommended levels for total cholesterol and low‐density lipoprotein cholesterol. The gender differences favoured women, for HbA$_{\rm{1c}}$, and men, for blood lipids. Individuals with the lowest income levels were less likely to reach the recommended level of HbA$_{\rm{1c}}$. Country of birth showed that immigrants from Middle Eastern countries and other countries had lower odds of reaching the recommended levels of HbA$_{\rm{1c}}$.

Conclusion

This study confirmed that risk factor control among patients with type 2 diabetes treated in primary health care is inadequate and that sociodemographic factors were associated with metabolic control. Future studies could include new strategies for the control of modifiable risk factors in patients with type 2 diabetes. Copyright © 2011 John Wiley & Sons, Ltd.
Expression patterns of ShcD and Shc family adaptor proteins during mouse embryonic development
Authors: Hawley Steve P. , Wills Melanie K.B. , Rabalski Adam J. , Bendall Andrew J. , Jones Nina
Published: November 2010

The Src homology and collagen (Shc) proteins function as molecular adaptors in signaling pathways mediated by a variety of cell surface receptors. Of the four mammalian Shc proteins, ShcD is the least characterized. To this end, ShcD expression was documented and compared to that of other Shc family proteins. In the developing mouse embryo, expression of ShcD overlaps with that of other Shc proteins in the central nervous system, with specific distribution in post‐mitotic neurons. In addition, robust ShcD expression is seen within differentiated epithelial cells of several organs, as well as in skeletal and cardiac muscle, and various tissues of neural crest origin. Interestingly, all Shc family members are expressed in hypertrophic chondrocytes, the first report of Shc protein expression in the developing skeleton. The unique tissue distribution patterns of Shc proteins likely contribute to their complex tissue‐specific signaling functions during embryogenesis. Developmental Dynamics, 2011. © 2010 Wiley‐Liss, Inc.
Serum and organ‐associated anti‐hemoglobin humoral autoreactivity: Association with anti‐Sm responses and inflammation
Authors: Bhatnagar Harshita , Kala Smriti , Sharma Latika , Jain Sonia , Kim Kwang Sik , Pal Rahul
Published: November 2010

The release of hemoglobin (Hb) occurs in some infectious and autoimmune diseases characterized by inflammation. As levels of haptoglobin (Hp) fall, free Hb can cause pathology. Humoral autoreactivity to human Hb was demonstrated in the sera of systemic lupus erythematosus (SLE), leishmania and malaria patients. Serum anti‐murine Hb antibody levels in lupus‐prone mice also exhibited an age‐dependent increase, with progressive organ sequestration; significant isotypic correlation was observed with anti‐dsDNA antibodies. A suggestive link between anti‐Hb and anti‐Sm responses was observed: Human lupus sera expressing anti‐Sm antibody reactivity preferentially contained heightened levels of anti‐Hb autoantibodies, and immunization of lupus‐prone mice with Sm led to enhanced anti‐murine Hb reactivity. Human and murine anti‐Hb monoclonal antibodies were generated, some of which were preferentially reactive toward disease‐associated methemoglobin. Epitope‐mapping studies revealed evidence of intra‐molecular cross‐reactivity. One such autoantibody synergized with Hb to enhance the secretion of pro‐inflammatory cytokines while eliciting the increased production of monocyte migratory signals from endothelial cells. Preferential usage of specific variable region gene segments was not observed, although somatic mutations were documented. These studies reveal that, while the etiology, specificity and sequences of anti‐Hb autoreactive antibodies can vary, they occur quite frequently and can have inflammatory consequences.
Identification of Diastereomeric Cyano–Aqua Cobinamides with a Backbone‐Modified Vitamin B12 Derivative and with 1H NMR Spectroscopy
Authors: Zhou Kai , Zelder Felix
Published: November 2010

A new backbone‐modified vitamin B12 derivative with an unusual configuration at the cobalt center has been used for the identification of the two axial diastereomers of cyano–aqua cobinamides (Cbi) by using 1H NMR spectroscopy.
Bedload: a granular phenomenon
Authors: Frey Philippe , Church Michael
Published: November 2010

Bedload, the transport of sediment remaining in contact with the stream bed, has mainly been studied from the perspective of the correlation between fluid driving forces and the responding sediment flux. Yet grain–grain interactions are important and bedload should also be considered as a granular phenomenon. We review progress made recently in the study of granular flows, especially on segregation and rheology, that better illuminates the nature of bedload. Granular flows may exhibit gas‐like or fluid‐like flow, or quasi‐solid deformation. All three conditions might be duplicated in bedload. Understanding of intense bedload transport occurring continuously in a layer several grains deep – typical of sand beds – might greatly benefit from results in granular physics, as illustrated by grain‐inspired bedload results. However, processes restricted to the surface of the bed, when particles move intermittently and the bed becomes structured, while characteristic in gravel‐bed channels, are not well addressed in granular physics. Mutual study of these phenomena may benefit both physics and fluvial geomorphology. We intend, therefore, to contribute to an enhanced dialogue between granular physics and bedload science communities. Copyright © 2010 John Wiley & Sons, Ltd.
Prognostic impact of marginal mandibulectomy in the presence of superficial bone invasion and the nononcologic outcome
Authors: Chen Yih‐Long , Kuo Shih‐Wei , Fang Ku‐Hao , Hao Sheng‐Po
Published: November 2010

Background

Treatment of oral cavity cancer may require variable extent of mandibular resection. Marginal mandibulectomy is a controversial technique in providing oncologic resection margin. This study analyzes the efficacy of local oncologic control and the morbidity of marginal mandibulectomy in oral cavity carcinoma. Nononcologic complication of osteoradionecrosis is discussed.

Methods

A retrospective cohort study analyzed clinicopathologic features of 43 patients with oral cavity cancer who underwent marginal mandibulectomy. Histologic mandibular invasion was examined as a function of local control and contribution to osteoradionecrosis.

Results

Bone invasion was present in 16.3% of patients with marginal mandibulectomy. Local control rates were 85.7% in the bone invasion group and 77.8% in the no bone invasion group (p = .7). Osteoradionecrosis rates were 16.7% and 17.6%, respectively (p = .96). There was no significant difference between the 2 groups.

Conclusions

Marginal mandibulectomy is oncologically sound in providing a safe resection margin in oral cavity cancer abutting or superficially invading the mandible. © 2010 Wiley Periodicals, Inc. Head Neck, 2011
Teamwork in production: Implementation, its determinants, and estimates for German manufacturing
Authors: Bikfalvi Andrea
Published: November 2010

The progressive use of teamwork as an element of workplace practices orients researchers to dedicate important efforts to study the phenomenon and its depths. Although team research has focused on a large variety of aspects—human, psychological, positional, technical, and economico‐strategic—less is known about the factors influencing or determining the incidence of such concepts. Implementation rates and the degree of spreading, as well as variables mentioned by previous studies as determinants, were tested on a sample of 1,298 manufacturing firms located in Germany. The results show that almost 2/3 of manufacturing establishments use teamwork in production and, on average, more than 50% of employees are involved in normally four‐ to nine‐person teams. The results of this study also sustain the initial hypothesis on the positive relationship among flexibility, complexity, new products, organizational concepts, and teamwork implementation in production. Theoretical and practical implications of the findings are discussed. © 2010 Wiley Periodicals, Inc.
Some empirical insights on diagnostic performance of the operating crew in a computer‐based advanced control room
Authors: Kim Jaewhan , Kim Jonghyun , Park Jinkyun , Jang Seung Cheol , Shin Yeong Cheol
Published: November 2010

As computer‐based design features are adopted in main control rooms of nuclear power plants, a human reliability analysis (HRA) method dealing with the effects of these design features on human behavior is needed. This article provides experimental results of human diagnostic performance characteristics in a computer‐based, full‐scope, dynamic simulator to inform some insights on developing an HRA method for a computer‐based advanced control room. In comparison to the performance time for diagnostic actions, it showed more or less faster performance in the computer‐based control room with a computer‐based emergency operating procedure (EOP) for an event scenario with an apparent diagnostic symptom than in the conventional control room with a paper‐based EOP, but it is also revealed that the diagnosis time is highly dependent on the situational characteristics of simulated events. Regarding the aspect of human error occurrence, a decision maker showed the potential for leading to a wrong conclusion regarding the plant state when he makes a situational assessment or makes a decision based on abnormal information by himself without communicating or consulting with other operators. Finally, regarding the aspects of error recovery, it showed that the error recovery potential becomes much higher for the advanced control room than for the conventional control room due to the information sharing and access capability of the advanced control room between and for all the crew members. It is expected that an HRA method for an advanced control room environment should adequately reflect these characteristics of human behavior in a computer‐based control room. © 2010 Wiley Periodicals, Inc.
Highly (≥98 %) Selective Trisubstituted Alkene Synthesis of Wide Applicability via Fluoride‐Promoted Pd‐Catalyzed Cross‐Coupling of Alkenylboranes
Authors: Negishi Ei‐ichi , Tobrman Tomas , Rao Honghua , Xu Shiqing , Lee Ching‐Tien
Published: November 2010

(Z)‐β‐bromo‐1‐propenyl(pinacol)borane (4), recently made available in 85 % yield as a ≥98 % isomerically pure compound via bromoboration of 1‐propyne, has been converted to β‐alkyl‐, aryl‐, and alkenyl‐substituted (Z)‐2‐methyl‐1‐alkenyl(pinacol)boranes (2a) in ca. 75 % yield based on propyne via Pd‐catalyzed Negishi alkenylation with suitable organozinc bromide. The previously sluggish and modest‐yielding Suzuki alkenylation of β,β‐disubstituted alkenylboranes has been significantly promoted by fluorides, especially nBu4NF(TBAF) or CsF, to give trisubstituted alkenes, i.e., (Z)‐β‐Me‐substituted 3‐i–3‐xi and (E)‐β‐Ph‐substituted 2b–i and 2b–ii. In all cases, each alkene product was formed in a ≥98 % stereoselectivity. The propyne‐based protocol nicely complements the widely used Zr‐catalyzed alkyne methylalumination–Pd‐catalyzed alkenylation by providing a highly stereoselective(≥98 %) route to (Z)‐Me‐substituted alkenes.
Detection of bulky DNA lesions: DDB2 at the interface of chromatin and DNA repair in eukaryotes
Authors: Jones Kristi L. , Zhang Ling , Seldeen Kenneth L. , Gong Feng
Published: November 2010

Bulky DNA damage is corrected by the nucleotide excision repair (NER) pathway. Although the core biochemical mechanism of NER is understood, details including lesion recognition and repair in the context of chromatin remain to be elucidated. As more data become available, the complexity of lesion recognition in chromatin is becoming clear. This review will discuss current knowledge of DNA damage recognition in the context of chromatin, with a focus on the roles of chromatin remodeling and the specific lesion recognition protein DDB2 (DNA damage‐binding protein 2) in chromatin repair. Additionally, we propose a model that ubiquitination‐mediated DDB2 dissociation from chromatin, not its degradation, is important for GG‐NER progression. © IUBMB IUBMB Life, 62(11): 803–811, 2010.
When Kahneman meets Manski: Using dual systems of reasoning to interpret subjective expectations of equity returns
Authors: Gouret Fabian , Hollard Guillaume
Published: November 2010

To understand how decisions to invest in stocks are taken, economists need to elicit expectations regarding risk–return tradeoff. One of the few surveys which has elicited such expectations is the Survey of Economic Expectations in 1999–2001. Using the data from this survey, Dominitz and Manski find considerable heterogeneity across respondents that cannot be explained by simple models of expectations formation. Adapting a principle of dual reasoning borrowed from Kahneman, this paper classifies respondents according to their sensitivity to some pathologies. We find a substantial amount of unobserved heterogeneity between the least and the most sensitive respondents. We then sketch a model of expectations formation. Copyright © 2010 John Wiley & Sons, Ltd.
2010 Panel on the Biomaterials Grand Challenges
Authors: Reichert William “Monty” , Ratner Buddy D. , Anderson James , Coury Art , Hoffman Allan S. , Laurencin Cato T. , Tirrell David
Published: November 2010

In 2009, the National Academy for Engineering issued the Grand Challenges for Engineering in the 21st Century comprised of 14 technical challenges that must be addressed to build a healthy, profitable, sustainable, and secure global community (http://www.engineeringchallenges.org). Although crucial, none of the NEA Grand Challenges adequately addressed the challenges that face the biomaterials community. In response to the NAE Grand Challenges, Monty Reichert of Duke University organized a panel entitled Grand Challenges in Biomaterials at the at the 2010 Society for Biomaterials Annual Meeting in Seattle. Six members of the National Academies—Buddy Ratner, James Anderson, Allan Hoffman, Art Coury, Cato Laurencin, and David Tirrell—were asked to propose a grand challenge to the audience that, if met, would significantly impact the future of biomaterials and medical devices. Successfully meeting these challenges will speed the 60‐plus year transition from commodity, off‐the‐shelf biomaterials to bioengineered chemistries, and biomaterial devices that will significantly advance our ability to address patient needs and also to create new market opportunities. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Internucleotide J‐couplings and chemical shifts of the NH···N hydrogen‐bonds in the radiation‐damaged guanine‐cytosine base pairs
Authors: Li Huifang , Zhang Laibin , Han Li , Sun Wenming , Bu Yuxiang
Published: November 2010

Internucleotide 2hJNN spin‐spin couplings and chemical shifts (δ(1H) and Δδ(15N)) of NH···N H‐bond units in the natural and radiation‐damaged G‐C base pairs were predicted using the appropriate density functional theory calculations with a large basis set. Four possible series of the damaged G‐C pairs (viz., dehydrogenated and deprotonated G‐C pairs, GC•− and GC•+ radicals) were discussed carefully in this work. Computational NMR results show that radicalization and anionization of the base pairs can yield strong effect on their 2hJNN spin scalar coupling constants and the corresponding chemical shifts. Thus, variations of the NMR parameters associated with the NH···N H‐bonds may be taken as an important criterion for prejudging whether the natural G‐C pair is radiation‐damaged or not. Analysis shows that 2hJNN couplings are strongly interrelated with the energy gaps (ΔELP→σ*) and the second‐order interaction energies (E(2)) between the donor N lone‐pair (LPN) and the acceptor σ*NH localized NBO orbitals, and also are sensitive to the electron density distributions over the σ*(NH) orbital, indicating that 2hJNN couplings across the NH···N H‐bonds are charge‐transfer‐controlled. This is well supported by variation of the electrostatic potential surfaces and corresponding charge transfer amount between G and C moieties. It should be noted that although the NMR spectra for the damaged G‐C pair radicals are unavailable now and the states of the radicals are usually detected by the electron spin resonance, this study provides a correlation of the properties of the damaged DNA species with some of the electronic parameters associated with the NMR spectra for the understanding of the different state character of the damaged DNA bases. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2011.
Exploring quality of life perceptions in rural midwestern (USA) communities: an application of the core–periphery concept in a tourism development context
Authors: Chancellor Charles , Yu Chia‐Pin Simon , Cole Shu Tian
Published: November 2010

Tourism has increasingly become a preferred option for rural economic development. Like other economic opportunities, the purpose is to improve community viability and residents' quality of life. However, the impacts from tourism are sometimes negative and may lead to a decreased quality of life for residents. This empirical study investigates residents' quality of life using the core–periphery (CP) model. Periphery respondents reported a statistically higher overall quality of life, which is at odds with other research. Significant differences in quality of life scores and subsequent indicators highlight the usefulness of the CP model towards understanding tourism impacts to a rural destination. Copyright © 2010 John Wiley & Sons, Ltd.
Constitutive release of powerful antioxidant-scavenging activity by hepatic stellate cells: Protection of hepatocytes from ischemia/reperfusion injury
Authors: Jameel Noor Mohamed , Thirunavukkarasu Chinnasamy , Murase Noriko , Cascio Michael , Prelich John , Yang Shuting , Harvey Stephen A. K , Gandhi Chandrashekhar R
Published: November 2010

Within the liver, reactive oxygen species produced by infiltrating blood cells and Kupffer cells (resident macrophages) can injure hepatocytes. We hypothesized that hepatocyte survival is influenced by the relatively small juxtaposed population of hepatic stellate cells (HSCs). We used cultures of primary rat hepatocytes as targets for superoxide-induced damage, which was determined by crystal violet assay and lactate dehydrogenase release. An HSC-conditioned medium prevented the superoxide-induced death of hepatocytes, and the protective factor released by HSCs was a protein or proteins (apparent molecular weight > 100 kDa) resistant to heat (70°C) and pH (4.5-8.5). The protein or proteins were partially purified on DE52 cellulose, and the active fraction contained no detectable levels of superoxide dismutase: after separation by Sephadex G-100 gel filtration, the antioxidant activity could be reconstituted by the combination of 2 protein peaks, and this reconstituted activity was protective both in vitro and against liver ischemia/reperfusion injury in intact rats. Mass spectrometry proteomic studies confirmed that this activity could not be attributed to any previously identified antioxidant protein. Thus, HSCs protect hepatocytes against oxidative damage through the production of a novel protein, the further purification of which may lead to the isolation of a powerful oxygen radical scavenger with clinical applications. Liver Transpl 16:1400–1409, 2010. © 2010 AASLD.
Thermo‐Responsive Polymer Brushes as Intelligent Biointerfaces: Preparation via ATRP and Characterization
Authors: Nagase Kenichi , Watanabe Minami , Kikuchi Akihiko , Yamato Masayuki , Okano Teruo
Published: November 2010

PIPAAm‐brush grafted glass substrates with various graft densities and chain lengths were prepared via surface‐initiated ATRP. Temperature‐dependent physicochemical properties of the surfaces were characterized by means of ATR/FT‐IR spectroscopy, XPS, AFM, and contact angle measurements. ATRP conditions influence the amount of grafted PIPAAm and the surface wettability and roughness of the substrate. Fibronectin adsorption and EC adhesion increased with decreasing density of PIPAAm brushes. EC adhesion was diminished with increasing PIPAAm graft length. Thus, the preparation of PIPAAm brush surface with various graft densities and chain lengths using the surface‐initiated ATRP is an effective method for modulating thermo‐responsive properties of surfaces.

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Preparation of Poly(p‐phenylenepyromelliteimide) Microspheres with Rugged Surfaces Using Crystallization During Isothermal Polymerization
Authors: Wakabayashi Kanji , Uchida Tetsuya , Yamazaki Shinichi , Kimura Kunio
Published: November 2010

Preparation of discrete PPPI microspheres was examined using the crystallization of oligomers during isothermal polymerization of PMDA and p‐phenylene diisocyanate, and that of pyromellitic dithioanhydride and PPDA in poor solvents. In contrast to PPPI microspheres with smooth surfaces that were previously prepared by phase‐separation during the polymerization of PPDA and PMDA, the microspheres obtained here consisted of flake‐like lamellae with rugged surfaces. The diameters of the microspheres ranged from 0.5 to 6.7 µm. They exhibited excellent thermal stability depending on the monomers. These results provide a new preparative procedure of the PPPI microsphere with a rugged surface.

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Hydroxy Functional Acrylates: Enzymatic Synthesis and Free Radical Polymerization
Authors: Popescu Dragos , Hoogenboom Richard , Keul Helmut , Möller Martin
Published: November 2010

Hydroxy functional acrylates were prepared via transacylation of methyl acrylate with 1,2,6‐hexanetriol catalyzed by Candida antarctica lipase B. Under the applied reaction conditions, 70% of the substrate was converted into hydroxy functional acrylates. In a subsequent step, after filtration of the enzyme, the monomer mixture containing methyl acrylate and the new monomers was polymerized via free radical polymerization resulting in a functional copolymer with Mn = 14500 g/mol.
Graft and RAFT Reactive Macro Reagents: Bis‐[copoly‐(divinyl ether‐alt‐maleic anhydride)]‐trithiocarbonate
Authors: Serbin Alexander , Karaseva Ekaterina , Chernikova Elena , Dunaeva Irina , Krutko Ekaterina , Filatova Marina , Zezin Alexander
Published: November 2010

The alternating cyclocopolymer of maleic anhydride with divinyl ether (MADVE) hydrolyzate, as mimicker of furan related and anionic residues alternation in nucleic acids (NA) backbone, is immune stimulating agonist and competitive antagonist for viral genome NA interventions. The targeted pre‐modification of MADVE by antiviral vectors via grafting to the MA anhydride residues before hydrolysis led to more potent and promising antiviral inhibitors. To develop the MADVE capacity for novel modifications we applied the reversible addition – fragmentation chain transfer (RAFT) technique using dibenzyl trithiocarbonate as a RAFT agent. The insertion of trithiocarbonate unit in polymeric chain provided a pseudo living RAFT‐polymerization, resulting in: 1) the effective control of polymerization degree (increased with time and conversion), and 2) the narrow dispersive (PDI = 1.1–1.2) products MADVE‐S‐CS‐S‐MADVE yield. These products can be used as novel polymeric RAFT‐agents for synthesis of new block‐copolymers MADVE‐(block)‐CS3‐(block)‐MADVE, for instance with polystyrene blocks. Combined together the RAFT‐ and graft‐ reactivity allows both modify the polymer backbone (RAFT‐synthesis) and regulate the side groups or branches (grafted to MADVE moieties) with final hydrolysis of unused anhydride units to acidic polyelectrolyte derivatives. This plural reactive capacity of the obtained macro reagents essentially enhances their potential as platform for purposed synthesis of novel (bio‐) functional polymeric compounds.
Synthesis and Characterization of Novel Sulfonated Hybrid Congo Red Membranes from Chlorofunctionalized Silsesquioxanes for Fuel Cell Application
Authors: Gültek Ahmet , Gökçen Yusuf , Köytepe Süleyman , Seçkin Turgay
Published: November 2010

A new sulfonated copolymers containing congo red groups were synthesized as a potential electrolyte for high temperature PEFCs. The resulting cross‐linked sulfonated hybrid congo red membranes showed greatly improved water stability in comparison with the uncrosslinked ones while high proton conductivity was maintained. sulfonated membranes have been tested with respect to fuel cell performance. Short term fuel cell test for 100 hr gave a stable performance. These membranes are less expensive compared to Nafion. New sulfonated proton exchange composites membranes were used biological fuel cells. Molasses which is the waste of sugar factory, was used in anode as fuel and different bacteria species was sowing. Potential change was reported in biological fuel cells.
Synthesis of New Anionic and Cationic Polymerizable Surfactants for Emulsion Polymerization of Styrene
Authors: Mekki Sofiane , Saïdi‐Besbes Salima , Elaïssari Abdelhamid , Valour Jean‐Pierre , Derdour Aïcha
Published: November 2010

New anionic and cationic maleic surfmers containing a benzyl or p‐vinylbenzyl hydrophobic tail were prepared and characterized. The behaviour of benzyl maleate hemiester in the emulsion polymerization process of styrene has been studied in the presence of potassium persulfate as initiator. The effect of surfmer concentration on particle diameter was particularly investigated.
Self‐Processing, Diffusion‐Based Photopolymers for Holographic Applications
Authors: Weiser Marc‐Stephan , Bruder Friedrich‐Karl , Fäcke Thomas , Hönel Dennis , Jurbergs David , Rölle Thomas
Published: November 2010

The new photopolymers for holographic applications described herein are based on a cross‐linked matrix in which the holographic grating is formed by photo‐polymerization of guest monomers in an interference pattern of the recording light. Diffusion of monomer, triggered by this photo‐polymerization, from the dark to the bright fringes of the interference pattern is the key parameter for creating high modulation in refractive index Δn during hologram recording. This leads to bright visual volume holograms with high diffraction efficiency. The holographic photopolymers are self‐processing. After recording the hologram only (incoherent) light exposure is necessary to bleach the final product and fix the hologram. Unlike earlier photopolymers used in holography, these new materials offer the advantages of no chemical or thermal processing combined with low shrinkage and detuning. Additionally, due to good light sensitivity the formation of the holograms is fast and the film obtained after curing is highly transparent, which makes the material suitable for both, reflection and transmission holography.
Enhanced Photostability and Red‐NIR Photosensitivity of Conjugated Polymer Charge‐Transfer Complexes
Authors: Ozimova Anastasiya E. , Bruevich Vladimir V. , Dittrich Thomas , Paraschuk Dmitry Yu.
Published: November 2010

A promising route to photostable and low‐bandgap polymer materials for optoelectronic and photonic applications could be utilization of donor‐acceptor ground‐state charge‐transfer complexes (CTCs) of wide‐bandgap conjugated polymers. In this work, we report our results on photostability and photoelectric studies of CTC between an archetypical conjugated polymer MEH‐PPV and low‐molecular‐weight acceptor 2,4,7‐trinitrofluorenone (TNF). By using the pump‐probe laser photobleaching technique, we show that the photodegradation rate of MEH‐PPV:TNF blend films decreases up to four orders of magnitude as compared with pristine MEH‐PPV. By using photocurrent and surface photovoltage spectroscopies, we demonstrate that the photoelectric sensitivity of the MEH‐PPV:TNF CTC can be deeply extended in the polymer optical gap down to 1 µm. However, the main drawback of the CTC studied is their low charge collection efficiency, and an approach to increasing it is discussed.
Micellization and Thermogelation of Poly(ether urethane)s Comprising Poly(ethylene glycol) and Poly(propylene glycol)
Authors: Loh Xian Jun , Cheng Lim Wan Ian , Li Jun
Published: November 2010

A series of multiblock poly(ether urethane)s comprising poly(ethylene glycol) (PEG), and poly(propylene glycol) (PPG) segments were synthesized. Their aqueous solutions exhibited thermogelling behavior at critical gelation concentrations (CGC) ranging from 8 to 12 wt%. The composition and structural information of the copolymers were studied by GPC and 1H NMR. The critical micellization concentration (CMC) and thermodynamic parameters for micelle formation were determined at different temperatures. The temperature response of the copolymer solutions were studied and found to be associated with the composition of the copolymers.
Characterization of the Orientation Parameters Around Crack Tips in Unfilled and Nanofilled Poly(propylene) Using in‐situ Synchrotron Small and Wide Angle Scanning Scattering Techniques
Authors: Feuchter Michael , Maier Günther , Zizak Ivo , Pinter Gerald , Kracalik Milan , Laske Stephan , Langecker Günter Rüdiger
Published: November 2010

The fracturing behavior of polymers and polymeric composites is of great interest in the scientific and application community. Especially in the case of silicate‐layered nanocomposites the influence of fillers on the fracturing behavior is still fairly unclear. Fractures of semicrystalline polymers are accompanied by various processes of which shearing and cavitations are the most common ones. Nanocomposite deformation due to the delamination of fillers seems to be the most practical way leading to fractures with relatively low strains. With the method of scanning small angle X‐ray scattering (SAXS) and wide angle X‐ray diffraction (WAXD) it is possible to combine information on the structural details with the position on the sample, with the actual position resolution of the investigation being defined by the size of the X‐ray beam used to scan the sample. By means of the application of synchrotron radiation it is nowadays possible to adjust the actual beam size to the dimensions of the region of interest, which is why it is an adequate tool for studying the deformation region near a crack tip.

In a native polypropylene sample, the fracturing process was accompanied by shear yielding as well as lamellae fragmentation and reorienting. In the highly deformed material near the crack tip fibrillated material could be found. However, in the polymeric nanocomposites (PNC) shearing, lamellae fragmentation, and fibrillation were hindered by the filler due to which the material did not have so much freedom to dissipate energy and fractures occurred much earlier. In this paper the comparison of a PNC and its native polymer is to provide an overview of the different deformation mechanism and the structural details around the crack tip.
Thermal and DMA Characterization of PTFE‐PMMA Nanocomposites from Core‐Shell Nanoparticles
Authors: Antonioli Diego , Laus Michele , Sparnacci Katia , Deregibus Simone , Kapeliouchko Valerj , Palamone Giovanna , Poggio Tiziana , Zuccheri Giampaolo , Passeri Rosita
Published: November 2010

The thermal and dynamic‐mechanical characteristics of three PTFE/PMMA nanoparticle samples are described. The shell forming PMMA, once isolated from the PTFE cores, exhibits a lower thermal stability than the PMMA component in the corresponding nanocomposite under both thermal and oxidative degradation conditions thus indicating a definite, though moderate, thermal reinforcement due to the morphology of the nanocomposites. An increase in the thermal stability under nitrogen atmosphere was observed as the PTFE amount increases. However under air, no difference is observed in the various systems. These observations suggest that only a physical shield can be exerted by the PTFE cores to the PMMA matrix possibly due to a weak interface between PTFE and the PMMA. This hypothesis is also substantiated by the DMA analysis.
FTIR‐ATR Monitoring and SEC/RI/MALLS Characterization of ATRP Synthesized Hyperbranched Polyacrylates
Authors: Gonçalves Miguel A. D. , Pinto Vigínia D. , Dias Rolando C. S. , Costa Mário Rui P. F. N.
Published: November 2010

This work reports the synthesis at 1 L scale of hyperbranched polyacrylates based upon acrylate/diacrylate monomers such as n‐butyl acrylate (nBA)/1,6‐hexanediol diacrylate (HDDA) and using atom transfer radical polymerization (ATRP). A FTIR‐ATR immersion probe was used to monitor the polymerization reaction. The dynamics of the build‐up of polymer structure was studied by off‐line analysis of samples at different reaction times by size exclusion chromatography (SEC) with detection of refractive index (RI) and multi‐angle laser light scattering (MALLS) signals, leading to molecular weight distribution and z‐average radius of gyration. Kinetic measurements and observed parameters of the molecular architecture are compared with theoretical predictions which can be used to design new synthesis strategies to improve the homogeneity of hyperbranched polymers. Another goal of this study was elucidating the impact on polymerization of secondary reactions such as intramolecular cyclizations. For comparison purposes, FRP (conventional radical polymerization) of the same monomers is also considered.
Ionic Complexes of Polyacids and Cationic Surfactants
Authors: Tolentino Ainhoa , de Ilarduya Antxon Martínez , Alla Abdelilah , Muñoz‐Guerra Sebastián
Published: November 2010

Comb‐like ionic complexes were prepared from polyuronic acids (pectinic and alginic acids) and alkyltrimethylammonium surfactants bearing linear alkyl chains with 18, 20 and 22 carbon atoms. In the condensed state, these complexes were able to self‐assemble in ordered structures which were thermally stable up to ∼200 °C. The complexes were analysed by DSC and WAXS/SAXS and compared to their analogous made from poly(γ‐glutamic acid). They all adopt a biphasic layered structure in which the main chain and the alkyl side chain alternate with a nanometric periodicity. Alkyl side chains were partially crystallized in these complexes and they show reversible melting at temperatures within the 60‐80 °C range depending on the length of the polymethylene segment.
Polystyrene–Polyperfluorooctylethyl acrylate Diblock Copolymers: The Effect of Dilution of the Fluorinated Mesogenic Chains on Bulk and Surface Properties
Authors: Martinelli Elisa , Fantoni Chiara , Gallot Bernard , Glisenti Antonella , Galli Giancarlo
Published: November 2010

Summary: Three smectic poly(styrene‐b‐perfluorooctylethyl acrylate) block copolymers (S‐b‐AF8) with different degrees of polymerization (n, m) of the relative blocks were synthesized by atom transfer radical polymerization (S, n = 25; AF8 m = 2, 6, 23). The mesophase structure and transition temperatures were investigated by DSC and WAXD. The block copolymer having the shortest fluorinated block was blended with a thermoplastic elastomer SEBS in different proportions, in order to look at the effect of a further dilution of the perfluorinated groups on non‐wetting properties. Thin films of the block copolymers as well as the blends exhibited large contact angles with both water and n‐hexadecane, which resulted in low solid surface tensions. XPS findings at different photoemission angles confirmed the effective surface segregation of the mesogenic chains of the fluorinated polymer block.
Elastomer‐Clay Nanocomposites: Effect of Elastomer Polarity
Authors: Susteric Zoran , Kos Tomaz
Published: November 2010

Dynamic mechanical properties of non‐polar and polar elastomer‐based nanocomposites with Montmorillonite clay are studied in order to ascertain differences caused by elastomer's polarity. Natural as non‐polar and polychloroprene as polar rubber are used to experimentally verify predictions based on different nature of elastomer‐clay interactions in the two cases. The properties foretold and elucidated in terms of van der Waals interactions in the non‐polar case and dipole‐dipole interactions in the polar case agree well with experiment, concurrently sustaining general depiction of these unusual nanocomposites.
Simulation of Chain Organization in Encapsulated Polymers
Authors: Cifra Peter , Bleha Tomas
Published: November 2010

Summary: The dimensional and structural properties of polymers confined into a cavity are computed by the Monte Carlo method as a function of the chain stiffness. The reduction of the size ratio  / < R> close to 2, distinctive of compact spheres, is observed at squeezing of chains into a capsule. The plots of the static structure factor S(q) computed for stiff chains show characteristic humps attributed to the toroidal structure. The orientation correlation function is found to be a very sensitive indicator of the globule – toroid transition in encapsulated chains. Evidence is presented that the toroidal morphology is formed in stiff polymers when the capsule radius approaches the chain persistence length (D ∼ P).
Core Cross‐Linked Polymerized Micelles and Dendronized Nanoparticles
Authors: Zorin Ivan M. , Makarov Ivan A. , Ushkova Tatiana S. , Melnikov Alexander B. , Antonov Eugeny A. , Bilibin Alexander Yu.
Published: November 2010

Polymerization of 11‐acryloylaminoundecanoic acid and its copolymerization with diacrylic monomers were performed under different conditions in micellar (Na‐salt in water) and non‐micellar states. The effect of conditions of the syntheses on molecular mass of the polymers and hydrodynamic characteristics of their macromolecules was studied. Ionic complexes of core‐cross‐linked polymerized micelles with different dendrons bearing polymerizable peripheral groups were obtained and their trial polymerizations were performed.
Phase Behaviour of Hydroxypropyl Cellulose/ Polyacrylamide Gels
Authors: Castro Carlos , Morales Ana , Koschella Andreas , Heinze Thomas
Published: November 2010

Summary: Polysaccharide‐based materials have gained nowadays a great importance in many fields of industry, e.g., in the pharmaceutical industry. Some characteristics of such compounds are their non‐toxicity and the presence of a lower critical solution temperature (LCST) and/or an upper critical solution temperature (UCST). This work presents results on the synthesis and characterization of composites from hydroxypropyl cellulose (HPC) and polyacrylamide (PAAm). The ratio of HPC/PAAm was varied as well as the concentration of the crosslinker and the pH value of the reaction mixture. The compounds prepared were characterized by means of Fourier Transform Infrared spectroscopy (FTIR) and turbidity measurements. FTIR spectroscopy showed the presence of the main structural features of the precursors in the gels. The turbidity measurements of the gels in water showed the presence of a LCST in all samples. The LCST decreased when the quantity of HPC was increased in the gel and diminished also with increasing quantities of crosslinker and pH. The turbidity measurement showed the presence of an UCST when the concentration of the polymer was higher than 1% (w/w). This phenomenon is caused by the presence of the PAAm, which acted as precipitant and influenced over the entropy of the system and provoked phase separation.
Phospholipid Bilayers as Molecular Models for Drug‐Cell Membrana Interactions. The Case of the Antiinflamatory Drug Diclofenac
Authors: Suwalsky Mario , Manrique Marcela , Villena Fernando , Sotomayor Carlos P.
Published: November 2010

Phospholipids are amphipatic molecules with long hydrophobic acyl chains and zwitterionic polar heads which assemble into different types of molecular aggregates. The most relevant is the bilayer because of its relation with cell membranes, which are very complex entities. For this reason, simpler molecular models based on phospholipids bilayers are widely used. We have determined the bilayer structure of phospholipids located in the outer and inner monolayers of most cell membranes, and use them as molecular models to study the way different chemicals of biological interest interact with cell membranes. We present the results of our studies on the nonsteroidal anti‐inflammatory drug diclofenac, from which little is known about its effects on human erythrocytes. This report presents the following evidence that diclofenac interacts with the human red cell membrane: a) X‐ray diffraction and fluorescence spectroscopy of phospholipids bilayers show that diclofenac interacts with a class of lipids found in the outer moiety of the erythrocyte membrane; b) in isolated unsealed human erythrocyte membranes the drug induced a disordering effect on the acyl chains of the membrane lipid bilayer; c) in scanning electron microscopy studies on human erythrocytes it was observed that the drug induced morphological changes different from their normal biconcave shape.
Multifunctional Polyesters for Bioartificial Vascular Prostheses
Authors: Theiler Stefan , Mela Petra , Keul Helmut , Möller Martin
Published: November 2010

Aliphatic polyesters of controlled molecular weight and low molecular weight distribution were prepared via anionic ring‐opening polymerization using a multifunctional star‐shaped initiator. Functionalization results in star‐shaped functional polyesters bearing methacrylate end groups. Novel biodegradable polyester resins were prepared by photochemical crosslinking of the functional polyesters. Three‐dimensional microstructuring via UV replica molding shows the potential of this material as substrate for biomedical devices.
FTIR Investigation of UHMWPE Oxidation Submitted to Accelerated Aging Procedure
Authors: Rocha Magda F. , Mansur Alexandra A. P. , Mansur Herman S.
Published: November 2010

In the present study, an accelerated ageing by oxidative degradation of UHMWPE in hydrogen peroxide solution was performed and the inhibition with ascorbic acid (vitamin C) was analyzed. Both systems were extensively characterized by Fourier Transformed Infrared Spectroscopy (FTIR). Different chemical groups of UHMWPE associated with the degradation reaction were monitored for over 120 days in order to evaluate the possible oxidation mechanisms involved and the inhibitory behavior of vitamin C. The results have provided strong evidence that the oxidation mechanism is rather complex, and 2 stages with their own particular first‐order kinetics reaction patterns have been clearly identified. Furthermore, the vitamin C has proven to be an efficient antioxidant for UHMWPE under the evaluated conditions.