bluuebunny/crossref_metadata_2025 huggingface dataset:
Overcoming Immunologic Tolerance to Melanoma: Targeting CTLA-4 with Ipilimumab (MDX-010)
Authors: Weber Jeffrey
Published: November 2008

Targeted biologic therapies such as anti–cytotoxic T lymphocyte antigen (CTLA-4) monoclonal antibodies, either as monotherapy or in combination with chemotherapy or vaccines, have shown great promise in late-stage melanoma, which has a very poor prognosis. Melanoma is relatively resistant to both chemotherapy and radiotherapy. Blockade of CTLA-4, which inhibits T-cell proliferation, promotes stimulation of adaptive immunity and T-cell activation, resulting in eradication of tumor cells. Two human monoclonal antibodies are under investigation in melanoma. Phase II and III clinical trials are currently evaluating the efficacy and safety of ipilimumab (MDX-010, Medarex, Inc., Princeton, NJ, and Bristol-Myers Squibb, Princeton, NJ) and tremelimumab (CP-675,206; Pfizer Pharmaceuticals, New York) in melanoma. Data are available on ipilimumab, which has been explored as monotherapy and in combination with vaccines, other immunotherapies such as interleukin-2, and chemotherapies such as dacarbazine. Overall response rates range from 13% with ipilimumab plus vaccine in patients with stage IV disease to 17% and 22% with ipilimumab plus dacarbazine or interleukin-2, respectively, in patients with metastatic disease. Responses have been durable, and among those experiencing grade 3 or 4 autoimmune toxicities, even higher response rates have been seen—up to 36%. While the optimal dose of ipilimumab has yet to be established, studies also indicate that higher doses may be more effective. Importantly, the lack of an initial clinical response may not predict ultimate treatment failure, because the onset of a response may follow progressive disease or stable disease. Pending results from registration studies with ipilimumab and lessons learned from registration studies conducted with tremelimumab will help to define the role of anti–CTLA-4 blockade in the treatment of metastatic melanoma.
The Mechanism of Anti-CTLA-4 Activity and the Negative Regulation of T-Cell Activation
Authors: Wolchok Jedd D. , Saenger Yvonne
Published: November 2008

The survival rate of patients diagnosed with late-stage melanoma is poor—only 5%–10%. Enlisting the immune system in the fight against cancers such as melanoma could help improve the prognosis of these patients. Data have shown that melanocyte proteins make good targets for immune system–based therapy in this disease. However, self-tolerance, which develops to inhibit autoimmune attack, makes this strategy difficult. Two proteins on the surface of T cells—CD28 and cytotoxic T-lymphocyte antigen 4 (CTLA-4)—play important roles in the regulation of immune activation and tolerance. CD28 provides positive modulatory signals in the early stages of an immune response, while CTLA-4 signaling inhibits T-cell activation, particularly during strong T-cell responses. CTLA-4 blockade using anti—CTLA-4 monoclonal antibody therapy has great appeal because suppression of inhibitory signals results in the generation of an antitumor T-cell response. Both clinical and preclinical data indicate that CTLA-4 blockade results in direct activation of CD4+ and CD8+ effector cells, and anti–CTLA-4 monoclonal antibody therapy has shown promise in a number of cancers, particularly melanoma. Interestingly, the occurrence of adverse events among patients treated with CTLA-4 blockade helps shed light on the mechanism of action of anti–CTLA-4 monoclonal antibodies. Most adverse events involve immune-related toxicity to the skin and gastrointestinal tract. Major gastrointestinal toxicity develops in up to 21% of treated patients, and while an objective response occurs in approximately 36% of melanoma patients who develop enterocolitis with treatment, an objective response is found in only 11% of patients who do not experience this adverse reaction.
Catastrophic multiple organ ischemia due to an anti‐Pr cold agglutinin developing in a patient with mixed cryoglobulinemia after treatment with rituximab
Authors: Ruch Joshua , McMahon Brandon , Ramsey Glenn , Kwaan Hau C.
Published: November 2008

Cold agglutinin disease occurring with cryoglobulinemia is a rare occurrence. Here, we report a patient with mixed cryoglobulinemia that was treated with rituximab and, after response, developed an anti‐Pr cold agglutinin that manifested with hemolysis and microvascular occlusion causing mesenteric ischemia and cerebral infarction. Unlike previous reports of patients with cryoglobulinemia and cold agglutinin disease, our patient did not have a detectable cryoprecipitate when his cold agglutinin manifested. Am. J. Hematol, 2009. © 2008 Wiley‐Liss, Inc.
Understanding hind limb weight support in chimpanzees with implications for the evolution of primate locomotion
Authors: Raichlen David A. , Pontzer Herman , Shapiro Liza J. , Sockol Michael D.
Published: November 2008

Most quadrupedal mammals support a larger amount of body weight on their forelimbs compared with their hind limbs during locomotion, whereas most primates support more of their body weight on their hind limbs. Increased hind limb weight support is generally interpreted as an adaptation that reduces stress on primates' highly mobile forelimb joints. Thus, increased hind limb weight support was likely vital for the evolution of primate arboreality. Despite its evolutionary importance, the mechanism used by primates to achieve this important kinetic pattern remains unclear. Here, we examine weight support patterns in a sample of chimpanzees (Pan troglodytes) to test the hypothesis that limb position, combined with whole body center of mass position (COM), explains increased hind limb weight support in this taxon. Chimpanzees have a COM midway between their shoulders and hips and walk with a relatively protracted hind limb and a relatively vertical forelimb, averaged over a step. Thus, the limb kinematics of chimpanzees brings their feet closer to the COM than their hands, generating greater hind limb weight support. Comparative data suggest that these same factors likely explain weight support patterns for a broader sample of primates. It remains unclear whether primates use these limb kinematics to increase hind limb weight support, or whether they are byproducts of other gait characteristics. The latter hypothesis raises the intriguing possibility that primate weight support patterns actually evolved as byproducts of other traits, or spandrels, rather than as adaptations to increase forelimb mobility. Am J Phys Anthropol, 2009. © 2008 Wiley‐Liss, Inc.
Photoinduced surface crosslinking of superabsorbent polymer particles
Authors: Jockusch Steffen , Turro Nicholas J. , Mitsukami Yoshiro , Matsumoto Makoto , Iwamura Taku , Lindner Torsten , Flohr Andreas , di Massimo Giuseppe
Published: November 2008

Superabsorbent polymer particles, consisting of partly neutralized, slightly crosslinked poly(acrylic acid), have been surface‐crosslinked photochemically. Surface crosslinking is required for many applications of superabsorbent polymers, such as disposable diapers, to control the flow and absorption of liquids in the gel bed. Photoinduced surface crosslinking has been achieved under UV irradiation (200–300 nm) with (NH4)2S2O8 as a photoactivated crosslinking agent. In comparison with the currently used thermal ester bridging method for surface crosslinking, the new photochemical method generates superabsorbent particles with superior properties, such as an improved flow of liquid through the gel bed, which utilizes the entire gel bed. These improved properties have been shown by water absorption capacity studies, fluid flow dynamics, environmental scanning electron microscopy, and low‐energy ion‐scattering studies. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation and characterization of hyperbranched polyester capillary columns used for the separation of basic proteins
Authors: Shou Chongqi , Zhang Zhiliang
Published: November 2008

A series of hyperbranched polyesters with pentaerythritol as the core were synthesized and coated on the inner surface of fused‐silica capillaries by chemical bonding. Three kinds of basic proteins were selected for studying the behavior of the adsorption to fused‐silica capillaries. Comparative studies of the coating materials were conducted, and the experimental results showed that the coated columns with hyperbranched polyesters could suppress the electroosmotic flow greatly and effectively prevent adsorption in the pH range of 4–6; they were superior to capillaries coated with traditional hydroxypropyl cellulose. Furthermore, research was conducted to study the effect of hyperbranched polyester generation on the column efficiency. The results showed that higher column efficiency was obtained on a capillary column coated with the sixth generation of the hyperbranched polyester at pH 5.0. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Quantification of surface forces of thermoplastic elastomeric nanocomposites based on poly(styrene‐ethylene‐co‐butylene‐styrene) and clay by atomic force microscopy
Authors: Ganguly Anirban , Bhowmick Anil K.
Published: November 2008

Atomic force microscopy was used for qualitative phase morphological mapping as well as quantitative investigation of surface forces measured at constituting blocks and clay regions of a thermoplastic elastomeric nanocomposite based on triblock copolymer: poly(styrene‐ethylene‐co‐butylene‐styrene) (SEBS) and organically modified nano‐clay. The roughness and power spectral density analyses of surface topography provided the increment in random roughness of the nanocomposite surface compared to pristine SEBS surface. The same surfaces were examined by means of single point force‐distance, and force‐volume measurements. Large adhesive force of 25 nN and contact force of 260 nN were found in soft polyethylene (PEB) segments and higher cantilever deflection of 210 nm was found for clay regions of SEBS‐clay nanocomposite. Mapping of elastic modulus of the glassy and rubbery blocks and clay regions was probed by employing Hertzian and JKR model from respective approaching and retracting parts of force‐distance curves. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
On the measurement of atmospheric gamma drop‐size distributions
Authors: Brawn Dan , Upton Graham
Published: November 2008

We consider concurrent data from two makes of laser disdrometer, fitting gamma distributions to each minute's data. We show that, as has been suggested elsewhere, there does appear to be a relationship between the shape and slope parameters. However, we present a revised formulation of the relationship and demonstrate that the relation appears to vary with the type of disdrometer used. Copyright © 2008 Royal Meteorological Society
Enhanced microwave‐assisted method for on‐bead disulfide bond formation: Synthesis of α‐conotoxin MII
Authors: Galanis Athanassios S. , Albericio Fernando , Grøtli Morten
Published: November 2008

A novel enhanced microwave‐assisted disulfide bridge formation method has been developed. To optimize the synthesis of the biologically important bicyclic peptide α‐conotoxin MII (α‐CtxMII), several cyclization methods have been tested and are discussed herein. By using m.w.‐assisted heating, we achieved high yields for the first loop cyclization of α‐CtxMII on‐bead. This method has the advantage of avoiding intermolecular by‐products during the cyclization step. Furthermore, the method gives higher yields compared with the common on‐bead cyclization methods. The second disulfide bridge of α‐CtxMII was formed using a simple oxidation method after the cleavage of the intermediate monocyclic peptide from the resin. This method has the potential to be efficient for the synthesis of other disulfide rich biologically important peptides. © 2008 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 92: 23–34, 2009.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
The virtues and vices of equilibrium and the future of financial economics
Authors: Farmer J. Doyne , Geanakoplos John
Published: November 2008

The use of equilibrium models in economics springs from the desire for parsimonious models of economic phenomena that take human reasoning into account. This approach has been the cornerstone of modern economic theory. We explain why this is so, extolling the virtues of equilibrium theory; then we present a critique and describe why this approach is inherently limited, and why economics needs to move in new directions if it is to continue to make progress. We stress that this shouldn't be a question of dogma, and should be resolved empirically. There are situations where equilibrium models provide useful predictions and there are situations where they can never provide useful predictions. There are also many situations where the jury is still out, i.e., where so far they fail to provide a good description of the world, but where proper extensions might change this. Our goal is to convince the skeptics that equilibrium models can be useful, but also to make traditional economists more aware of the limitations of equilibrium models. We sketch some alternative approaches and discuss why they should play an important role in future research in economics. © 2008 Wiley Periodicals, Inc. Complexity, 2009
OTA‐based transmission line model with variable parameters for analog power flow computation
Authors: Leger Aaron St. , Nwankpa Chika
Published: November 2008

Analog computation has some inherent benefits over traditional digital computation methods and fosters a continued interest in research, specifically in power systems, due to its associated strengths. Among these advantages are physically realizable solutions, much faster computation times and more accurate models. To realize an analog computation environment for power system analysis analog models and their circuit realizations are required. This paper focuses on the design, simulation and hardware verification of transmission line models with variable parameters for the purpose of analog power flow computation. Specifically, pi equivalent lumped parameter and distributed parameter transmission line models with parametric variation based on temperature and frequency are presented. Operational transconductance amplifiers (OTAs) are the primary circuit elements in the hardware designs and allow remote reconfigurability and variation of transmission line parameters via transconductance gain. Test results are presented from a hardware prototype, which was developed and tested based on the proposed analog line models. Copyright © 2008 John Wiley & Sons, Ltd.
Processing methods for partially encrypted data in multihop Web services
Authors: Nakayama Kojiro , Oba Michiko , Aramoto Michitaka , Komoda Norihisa
Published: November 2008

Message layer security is necessary to ensure the end‐to‐end security of Web services. To provide confidentiality against the intermediaries along the message path, XML encryption is used to partially encrypt the message. Because the data structure is changed by the partial encryption, the encrypted message is no longer valid with respect to the original schema definition. Thus, problems occur regarding the processing of the schema validation and the data binding by the intermediary. In this paper, we discuss two possible methods to solve these problems. The first method is to transform the original schema definition. The second is to transform the received message. We examined these methods by applying them to demonstration experiment of Web services. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(5): 26– 32, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10112
Development of a large‐current high‐precision pulse power supply
Authors: Takayanagi Tomohiro , Koseki Shoichiro , Kubo Hiroshi , Katoh Shuji , Ogawa Shinichi
Published: November 2008

JAEA and KEK are jointly constructing a high‐intensity proton accelerator project J‐PARC. Its main accelerator is a 3‐GeV synchrotron. Its injection bump magnets, especially horizontal paint bump magnets, are excited by large pulse currents. Their rated currents are over 10 kA and pulse widths are about 1 ms. Tracking errors are required to be less than 1%. Multiple connected two‐quadrant IGBT choppers are adopted for their power supplies. Their output currents are controlled by feedback control with minor loop voltage control (m‐AVR). When output current of a chopper intermits at small current, its output voltage rises and current control becomes difficult. In this paper, response of m‐AVR and output voltage characteristics at current intermittent region are studied and an improved control scheme is proposed. The performance is confirmed by a test. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(3): 62– 72, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20783
Rel/NF‐κB family member RelA regulates NK1.1− to NK1.1+ transition as well as IL‐15‐induced expansion of NKT cells
Authors: Vallabhapurapu Sivakumar , Powolny‐Budnicka Iwona , Riemann Marc , Schmid Roland M. , Paxian Stephan , Pfeffer Klaus , Körner Heinrich , Weih Falk
Published: November 2008

Development of NKT cells was shown to depend on lymphotoxin (LT) and IL‐15 signaling pathways as well as on cytokine receptor common γ chain. After positive selection, NKT‐cell precursors transit through progressive maturation stages including proliferative expansion within the NK1.1− window. The transcription factors that integrate different signaling pathways into different stages of NKT‐cell development are not well characterized. Here, we show that the Rel/NF‐κB family member RelA regulates the NK1.1− to NK1.1+ transition during NKT‐cell development. RelA is also required for both IL‐15‐ and IL‐7‐induced proliferation of CD44hiNK1.1− NKT‐cell precursors. Activation of the invariant NKT‐cell receptor induces both IL‐15 receptor α and γ chains' expression in an NF‐κB‐dependent manner, suggesting a molecular mechanism by which NF‐κB regulates NKT‐cell development. NF‐κB also regulates TCR‐induced expression of LT‐α and LT‐β within NKT cells. In contrast to previous reports, however, we show that LT signaling is dispensable for thymic NKT‐cell development but is essential for their colonization of peripheral organs such as liver.
Highly Luminescent Superparamagnetic Diterbium(III) Complex Based on the Bifunctionality of p‐tert‐Butylsulfonylcalix[4]arene
Authors: Kajiwara Takashi , Hasegawa Miki , Ishii Ayumi , Katagiri Kensuke , Baatar Munkhtsetseg , Takaishi Shinya , Iki Nobuhiko , Yamashita Masahiro
Published: November 2008

A diterbium(III) complex was synthesized by using p‐tert‐butylsulfonylcalix[4]arene, which adopts a 1,2‐alternate conformation, acts as a sensitive optical‐antenna chromophore for UV and near‐UV light and causes easy‐axis magnetic anisotropy in the TbIII ions. The complex showed efficient ff emission with a corrected quantum yield of ca. 85 % even at room temperature. In addition, it showed superparamagnetic behaviour due to slow magnetic relaxation at low temperatures.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Temporal control of drug release from biodegradable polymer: Multicomponent diclofenac sodium releasing PLGA 80/20 rod
Authors: Nikkola Lila , Viitanen Petrus , Ashammakhi Nureddin
Published: November 2008

In our previous studies we have reported on the development of diclofenac sodium (DS) releasing rods. However, their drug release profiles were unsatisfactory. To enhance the drug release properties of the implant, we have developed a system whereby various elements can be combined into one implant. Melt extruded, self‐reinforced (SR), and sterilized (S) DS‐containing SR‐PLGA 80/20 billets were combined to produce multicomponent implants with various compositions. These components were basically heat pressed together to form multicomponent rods. Drug release from single component and multicomponent rods was defined using a UV‐Vis spectrophotometer. DS was released from individual components within 82–111 days and from multicomponent rods within 50–70 days. Thermal properties were analyzed using differential scanning calorimetry (DSC). The melting temperature (Tm) of multicomponent implants was about 157°C, change in heat fusion (ΔH) was 13.3 J/g, and the glass transition temperature (Tg) was 55.4°C. Mechanical strength was measured for 2 weeks and it decreased from 55 to 15 MPa. In conclusion, by compression molding three components with different release rates it is possible to control the temporal release from multicomponent rods. Released DS concentrations were within range for 49–74 days depending on the fractions of individual components used. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
The combination of stabilized plasmid lipid particles and lipid nanoparticle encapsulated CpG containing oligodeoxynucleotides as a systemic genetic vaccine
Authors: Wilson Kaley D. , de Jong Susan D. , Kazem Mikameh , Lall Ryan , Hope Michael J. , Cullis Pieter R. , Tam Ying K.
Published: November 2008

Background

DNA vaccines offer unique potential for generating protective and therapeutic immunity against infectious and malignant diseases. Unfortunately, rapid degradation and poor cellular uptake has significantly limited the efficacy of ‘naked’ plasmid DNA vaccines. We have previously described stabilized plasmid lipid particles (SPLP) as effective nonviral gene delivery vehicles for the transfection of tumours at distal sites following intravenous administration. Based on their low toxicity and favourable transfection profile following systemic administration, we investigate SPLP as gene delivery vehicles for the generation of a systemically administered genetic vaccine.

Methods

The uptake of SPLP and their ability to transfect splenic antigen presenting cells (APC) following systemic administration is assessed through fluorescently‐labelled SPLP in combination with phenotype markers and a very sensitive flow cytometry‐based assay for the detection of the transgene, beta‐galactosidase. The priming of antigen‐specific adaptive and humoural immune responses following vaccination with SPLP alone or in combination with liposomal nanoparticle encapsulated CpG‐ODN containing oligodeoxynucleotides (LN CpG‐ODN) is characterized through the use of antigen‐specific cytotoxicity assays, interferon‐γ secretion assays and enzyme‐linked immunosorbant assay.

Results

We demonstrate that SPLP are taken up by and transfect APC in the spleen following intravenous administration and that, in the presence of a strong immunostimulatory signal provided by LN CpG‐ODN, are able to prime transgene‐specific humoural and cellular immune responses.

Conclusions

SPLP represent an effective candidate for the nonviral delivery of a systemic genetic vaccine when combined with additional immune stimulation provided by LN CpG‐ODN. Copyright © 2008 John Wiley & Sons, Ltd.
Detection of explosives on human nail using confocal Raman microscopy
Authors: Ali Esam M. A. , Edwards Howell G. M. , Hargreaves Michael D. , Scowen Ian J.
Published: November 2008

Trace amounts of explosives were detected on human nail using confocal Raman microscopy. Contamination of the nail can result from the manual handling, packaging or transportation of explosive substances. Raman spectra were obtained from pentaerythritol tetranitrate (PETN), trinitrotoluene (TNT), ammonium nitrate and hexamethylenetetramine (HMTA) particles on the surface of the nail with dimensions in the range 5–10 µm. An added difficulty in an analytical procedure is the presence of a nail varnish coating that has been applied, which traps the particulate matter between the coating and nail. Using confocal Raman microscopy, interference‐free spectra could be acquired from particles of explosives visually masked by the nail varnish. Spectra of the explosives could be readily obtainedin situwithin 90 s without alteration of the evidential material. Acquisition of a Raman point map of a PETN particle under the nail varnish coating is also reported. Copyright © 2008 John Wiley & Sons, Ltd.
Effect of signal intensity normalization on the multivariate analysis of spectral data in complex ‘real‐world’ datasets
Authors: Beattie J. Renwick , Glenn Josephine V. , Boulton Michael E. , Stitt Alan W. , McGarvey John J.
Published: November 2008

Spectral signal intensities, especially in ‘real‐world’ applications with nonstandardized sample presentation due to uncontrolled variables/factors, commonly require additional spectral processing to normalize signal intensity in an effective way. In this study, we have demonstrated the complexity of choosing a normalization routine in the presence of multiple spectrally distinct constituents by probing a dataset of Raman spectra. Variation in absolute signal intensity (90.1% of total variance) of the Raman spectra of these complex biological samples swamps the variation in useful signals (9.4% of total variance), degrading its diagnostic and evaluative potential.

Using traditional spectral band choices, it is shown that normalization results are more complex than generally encountered in traditionally designed sample sets investigating limited chemical species. We demonstrate that no choice of a single band proves to be appropriate for predicting all the reference parameters, instead requiring a tailored normalization routine for each parameter.

Of the reference parameters studied in the chosen system, signals from pathogenic adducts in ocular tissues called advanced glycation endproducts were most prominent when normalizing about the 1550–1690 cm−1 region of the spectrum (17.5% of total variance, compared with 0.3% for unnormalized), while prediction of pentosidine and gender were optimized by normalization about the 1570 (R2 = 0.97 vs 0.57 for unnormalized) and 1003 cm−1 (p < 0.0000001 vs p < 0.01 for unnormalized) bands, respectively. The data obtained point to the extreme sensitivity of multivariate analysis to signal intensity normalization. Some general guidelines for making appropriate band choices are given, including the use of peak‐finding routines. Copyright © 2008 John Wiley & Sons, Ltd.
Fun in the family: tourism and the Commonwealth Games
Authors: Lockstone Leonie , Baum Tom
Published: November 2008

This paper uses the context of the Commonwealth in order to focus on a specific dimension of tourism that is located within it, that of the mega all‐Commonwealth event, the Commonwealth Games, and its impact in tourism terms. Sports events and tourism are closely linked and it is abundantly clear that the tourism potential of mega sporting events such as the Commonwealth Games is a major factor in encouraging cities to bid to host such events. Such tourism potential relates to the immediate attraction of the event to athletes and officials associated with the event, volunteers and paid employees who work at the event and, in particular, international and domestic visitors as games spectators and participants. This paper sets the Commonwealth Games in the wider context of sports tourism and will address their impact through consideration of the 2006 Commonwealth Games in Melbourne, Australia. Copyright © 2008 John Wiley & Sons, Ltd.
Tourism and income distribution in East Africa
Authors: Blake Adam
Published: November 2008

Research has highlighted the possibility that tourism expenditure in developing countries not only provides income for poor households, but also leads to contraction of other exporting industries. By highlighting the linkages between tourism‐related industries and the rest of the economy, and through the distributional effects of their income flows, this paper examines the effects of tourism‐related industries and other export industries on households in East Africa. Tourism‐related industries are found to provide substantially less income for poorer households than other export activities, leading to concern that tourism expansion may be detrimental for poverty alleviation in these countries. Copyright © 2008 John Wiley & Sons, Ltd.
The Preparation and Enzyme Immobilization of Hydrophobic Polysiloxane Supports
Authors: Cao Shunsheng , Liu Bailing
Published: November 2008

Enzymes are versatile biocatalysts and find increasing applications in many areas. The major advantages of using enzymes in biocatalytic transformations are their chemo‐, regio‐, and stereospecificity, as well as the mild reaction conditions that can be used. However, even when an enzyme is identified as being useful for a given reaction, its application is often hampered by its lack of long‐term stability under process conditions, and also by difficulties in recovery and recycling. For ease of application and stabilization purposes, enzymes are often immobilized on solid supports. Among support matrices, hydrophobic biomaterials have been extensively used as supports for enzyme immobilization because the hydrophobic interactions not only can effectively increase the amount of enzyme immobilization, but also exhibit higher activity and retention of activity compared with hydrophilic supports. On the other hand, polysiloxane can evidently increase the amount of enzyme immobilization because of its hydrophobicity and strong affinity with enzyme. Therefore, this research details the first preparation and use of a hydrophobic polysiloxane support for enzyme immobilization in which the structural and functional characteristics of new supports have been investigated by using glucose oxidase (GOD) and a simple Fenton's assay method, and extremely interesting features were revealed. The results showed that the amount of GOD immobilization and the stability of GOD loaded, which are fundamental properties for enzyme separation and purification, can be significantly improved by adsorption. Moreover, the results indicated that hydrophobic polysiloxane supports can effectively increase the enzymatic affinity and durability of GOD, and decrease the rate of GOD desorbed.

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Application of thermally sprayed coatings of the type WC/CoCr in reverse osmosis processes for seawater desalination
Authors: Dwars A. , Kochanowski W. , Schramm B. , Sehr F.
Published: November 2008

Seawater desalination based on the reverse osmosis process requires a variety of hydraulic systems. The material concepts of these hydraulic systems are designed to reliably resist the corrosive properties of seawater and brine as well as the tribological loads. Strong tribological loads typically occur during the start‐up and shutdown of multi‐stage high‐pressure pumps. Thermally sprayed coatings can be used to increase the wear resistance and also the tribological properties of bearings. Also in pressure exchangers for energy recovery, high tribological loads occur on the surfaces of rotors which operate with a clearance gap of 40–100 µm. Today, thermally sprayed coatings are used for the surface protection of these rotors. To resist the various tribological loads, the material pairs are optimized for each case. Thermally sprayed coatings with high surface hardness have proven to be particularly successful. A coating system, based on a CoCr matrix, has been developed especially for these applications.
Ethylene Polymerization over Homogeneous and Supported Catalysts Based on Bis(imino)pyridine Co(II) Complex: Data on the Number of Active Centers and Propagation Rate Constant
Authors: Barabanov Artem A. , Bukatov Gennady D. , Zakharov Vladimir A. , Semikolenova Nina V. , Echevskaja Ljudmila G. , Matsko Michail A.
Published: November 2008

The number of active centers (CP) and propagation rate constant (kP) for ethylene polymerization with homogeneous catalyst LCoCl2 + MAO and supported catalyst LCoCl2/SiO2 + Al(i‐Bu)3, where L is 2,6‐(2,6‐(Me)2C6H3N = CMe)2C5H3N, have been determined using the method of polymerization quenching by radioactive carbon monoxide (14CO). The unstable rate profile of the reaction was attributed to a decrease in the number of active centers from 0.23 to 0.14 mol · mol−1(Co) corresponding to an increase in the reaction time from 5 to 15 min, whereas the kP value remained constant, amounting to 3.5 × 103 L · mol−1 · s at 35 °C. A narrow molecular weight distribution of the obtained polyethylene (PE) samples ($\overline M _{\rm w} /\overline M _{\rm n}$ = 1.9) testifies that the homogeneous catalyst LCoCl2 + MAO can be regarded as a single‐site system. The activity of the supported catalyst was stable and noticeably lower than that of the homogeneous catalyst due to the low concentration of the active centers (0.02–0.03 mol · mol−1(Co)). PE with a broad molecular weight distribution ($\overline M _{\rm w} /\overline M _{\rm n}$ = 36) and noticeably higher molecular weight is formed in the presence of the supported catalysts. The activity of the supported catalyst increases sharply at polymerization in the presence of hydrogen. The data obtained on the CP and kP values allow suggesting the formation of the “dormant” centers at polymerization without hydrogen and regeneration of the active centers in the presence of hydrogen. The average kP values for the supported catalyst containing multiple active centers were determined to be 5.9 × 103 and 10.5 × 103 L · mol−1 · s, respectively, at 35 and 50 °C.

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Synthesis of Novel Conjugated Polyelectrolytes for Organic Field‐Effect Transistors Gate Dielectric Materials
Authors: Sun Mingliang , Lan Linfeng , Wang Li , Peng Junbiao , Cao Yong
Published: November 2008

Conjugated polyelectrolytes and their neutral precursors: aminoalkyl‐substituted polyfluorenes (PFNs) with different 4,7‐bis(N‐methylpyrrol‐2‐yl)‐2,1,3‐benzothiadiazole (PBT) contents were synthesized by Suzuki coupling reaction. Their quaternized ammonium polyelectrolyte derivatives were obtained through a post‐polycondensation treatment on the terminal amino groups. The resulting copolymers PFNBr–PBT are soluble in polar solvents such as methanol, DMF, and DMSO. Using the conjugated polyelectrolytes PFNBr–PBT5 as gate dielectric material, poly(3‐hexylthiophene) (P3HT) ‐based field‐effect transistors (FETs) show a high drain current of almost 4.5 mA within a gate voltage of only −3 V. The calculated hole mobility of P3HT is about 0.58 cm2 · V−1 · s−1.

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In situ Collapse of Phase‐Separated Structure by Covalent Bond Cleavage at a Branching Point upon Heating
Authors: Sato Eriko , Kitamura Tomoaki , Matsumoto Akikazu
Published: November 2008

A branched copolymer containing a degradable polyperoxide linkage at a branching point was synthesized by the radical copolymerization of dienyl‐functionalized polystyrene and polyisoprene macromonomers with molecular oxygen. The ternary mixture of the branched copolymer and the macromonomers showed phase‐separated structure after annealing at 45 and 90 °C. The adjacent spacing of the phase‐separated structure was in the order of submicron to micrometer, which is larger than that of general microphase separated structures, due to the presence of homopolymers (macromonomers). Annealing at 110 °C induced thermal decomposition of the polyperoxide followed by in‐situ collapse and a drastic morphology change in the phase‐separated structure.

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Fabrication of Honeycomb‐Structured Poly(DL‐lactide) and Poly[(DL‐lactide)‐co‐glycolide)] Films and their Use as Scaffolds for Osteoblast‐Like Cell Culture
Authors: Chaudhuri Julian B. , Davidson Matthew G. , Ellis Marianne J. , Jones Matthew D. , Wu XuJun
Published: November 2008

Summary: Surfactant‐free honeycomb‐structured Poly(DLlactide) (PDLLA) and Poly‐(DLlactide‐co‐glycolide) PDLLGA thin films were fabricated by water droplet templating methods. Thin films with uniform pore structure were obtained after controlled evaporation of solvents in a humid atmosphere. Solvent, polymer concentration and humidity were found to be important factors in the formation of honeycomb‐structured thin films. Preliminary cell culture studies with MG‐63 osteoblast‐like cell lines showed promising degrees of cell attachment and proliferation on these films, suggesting that they are applicable as scaffolds for tissue engineering.
Cellular Response after Stimulation of the Gelatin‐Alginate Matrixes
Authors: Szymonowicz Maria , Pielka Stanisław , Marcinkowska Anna , Żywicka Bogusława , Gamian Andrzej , Haznar Dorota , Pluta Janusz
Published: November 2008

Summary: In the study the evaluation of the influence of gelatin‐alginate matrixes on cells of Jurkat, A549 and Hurvec lines in in vitro tests was presented. Cellular cultures in the presence of the evaluated matrixes did not change their morphotic features and their count and proliferation. Gelatin‐alginate matrixes in the form of sponges do not have anty cytotoxicy.
Molar Mass and Structural Characteristics of Poly[(lactide‐co‐(aspartic acid)] Block Copolymers
Authors: Poljanšek Ida , Gričar Maja , Žagar Ema , Žigon Majda
Published: November 2008

Summary: We report on various synthetic procedures for the preparation of biodegradable and biocompatible poly(lactide‐co‐aspartic acid) block copolymers based on natural monomeric units – lactic acid and aspartic acid. Multiblock poly(lactide‐co‐aspartic acid) copolymers of different comonomer composition were synthesized by heating a mixture of L‐aspartic acid and L,L‐lactide in melt without the addition of any catalyst or solvent and with further alkaline hydrolysis of the cyclic succinimide rings to aspartic acid units. Diblock poly(lactide‐co‐aspartic acid) copolymers with different block lengths were prepared by copolymerization of amino terminated poly(β‐benzyl‐L‐aspartate) homopolymer and L,L‐lactide with subsequent deprotection of the benzyl protected carboxyl group by hydrogenolysis. The differences in the structure, composition, molar mass characteristics, and water‐solubility of the synthesized multiblock and diblock poly(lactide‐co‐aspartic acid) copolymers are discussed.
Improving the Processing Ability and Mechanical Strength of Starch/Poly(vinyl alcohol) Blends through Plasma and Acid Modification
Authors: Yang Sung‐Yeng , Liu Chia‐I , Wu Jing‐Yi , Kuo Ju‐Chien , Huang Chi‐Yuan
Published: November 2008

Summary: In this study, maleic anhydride (MA), and citric acid (CA) used as the processing additive and plasma treatment to improve the processing ability and mechanical strength of biodegradable starch/poly (vinyl alcohol) (PVA) blends were studied. The melt flow index (MFI) of starch/ glycerol/PVA (300g/60g/80g) blend was increased from 2.3g/10min to 32.7g/10min by adding 3g of MA and to 130 g/10min by adding MA and plasma treatment. The tensile strength of starch/glycerol/PVA blend increased from 3.48 to 6.21 MPa by adding 1.5g of MA and 1.5g of CA, while it increased to 6.26 MPa by plasma treatment. Esterification reaction which was evidenced by FTIR has been showed to improve the compatibility between starch and PVA when MA was dissolved into glycerol and glycerol grafted onto plasma pretreatment PVA. Thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) imaging were used to study the morphology of extruded blends.
Level‐cut inhomogeneous filtered Poisson field for two‐phase microstructures
Authors: Grigoriu Mircea
Published: November 2008

Level‐cut homogeneous filtered Poisson fields developed in (J. Appl. Phys. 2003; 94(6):3762–3770) to model two‐phase microstructures are defined, and their properties are briefly reviewed. Filtered Poisson fields are sums of randomly scaled and oriented kernels that are centered at the points of homogeneous Poisson fields. The cuts of these fields above specified thresholds are called level‐cut homogeneous filtered Poisson fields. It is shown that an arbitrary inhomogeneous Poisson field becomes homogeneous if observed in new coordinates, and that the mapping relating inhomogeneous and homogeneous Poisson fields can be constructed in a simple manner. This mapping and the model in (J. Appl. Phys. 2003; 94(6): 3762–3770) provide an efficient algorithm for generating arbitrary inhomogeneous two‐phase microstructures. Developments in (Int. J. Numer. Meth. Engng 2008; DOI: 10.1002/nme.2340), using arguments essentially identical to those in (J. Appl. Phys. 2003; 94(6):3762–3770) to define and generate inhomogeneous Poisson fields, overlook the natural extension of results in (J. Appl. Phys. 2003; 94(6): 3762–3770) to these fields provided by the mapping constructed in this paper. Copyright © 2008 John Wiley & Sons, Ltd.
Isolation of three stem cell lines from human sacrococcygeal teratomas
Authors: Busch Christian , Bareiss Petra M , Sinnberg Tobias , Just Lothar , Wehrmann Manfred , Fuchs Jörg , Garbe Claus , Drews Ulrich
Published: November 2008

Sacrococcygeal teratomas (SCTs) are benign tumours of the newborn with absolute indication for surgery directly after birth. We recently described the presence of stem cells positive for the stem cell markers nanog and Oct4 in SCTs. Here we report the isolation of three stem cell lines from three different SCTs. Cells were propagated in mesenchymal or in embryonic stem cell medium. Non‐clonal homogeneous stem cell lines were obtained after two to three passages and characterized in vitro by immunocytochemistry, RT‐PCR, western blot, FACS analysis, and metaphase spreads. The differentiation potential was tested in vitro and in vivo. The isolated cell lines, which we refer to as human sacrococcygeal teratoma stem cells (hSctSCs), express nanog, Oct4 and stella, and are negative for malignancy markers alpha‐fetoprotein and carcinoembryonic antigen. They can be induced in vitro to express neuronal, osteogenic, and chondrogenic traits. After grafting in vivo, spontaneous integration into the neural crest of the chick embryo and teratoma formation in the nude mouse were obtained. Our results indicate that SCTs are derived from remnants of the epiblast‐derived primitive streak, which in the human embryo normally regresses but forms teratomas in children affected with SCT. The hSctSCs therefore may be comparable to mouse epiblast‐derived stem cells (EpiSCs) and share characteristic features with human embryonic stem (hES) cells. Thus, SCT tissue obtained after surgery appears to be a novel source for the generation of human stem cells without the ethical implications associated with hES cells. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Identification of potential substrate proteins for the periplasmic Escherichia coli chaperone Skp
Authors: Jarchow Svenja , Lück Carsten , Görg Angelika , Skerra Arne
Published: November 2008

The “seventeen kilodalton protein” (Skp) is a predominant periplasmic chaperone of Escherichia coli, which is involved in the biogenesis of abundant outer membrane proteins (OMPs) such as OmpA, PhoE, and LamB. In this study the substrate profile of Skp was investigated in a proteomics approach. Skp was overexpressed in a deficient E. coli strain as a fusion protein with the Strep–tag and captured, together with any host proteins associated with it, from the periplasmic cell extract under mild conditions via one‐step Strep–Tactin affinity chromatography. Copurified substrate proteins were then identified by high resolution 2‐DE with immobilized pH‐gradients, followed by MALDI‐TOF MS. Apart from the known Skp substrates, including OmpA and LamB, more than 30 other interacting proteins were detected, especially from the outer membrane, among these FadL and BtuB, and from the periplasm such as MalE and OppA. Thus, Skp does not only serve as a specialized chaperone for a small set of OMPs, but it seems to exhibit a broader substrate spectrum, including soluble periplasmic proteins. These findings should prompt further investigation into the physiological role of Skp and may promote its use for the bacterial production of biochemically active heterologous proteins whose folding requires secretion into the oxidizing milieu of the periplasm.
A versatile peptide pI calculator for phosphorylated and N‐terminal acetylated peptides experimentally tested using peptide isoelectric focusing
Authors: Gauci Sharon , van Breukelen Bas , Lemeer Simone M. , Krijgsveld Jeroen , Heck Albert J. R.
Published: November 2008

We experimentally demonstrate the use of an in‐house developed pI calculator which takes into account peptide PTM such as phosphorylation and N‐terminal acetylation. The pI calculator was utilized for a large set of peptides derived from a complex zebrafish lysate fractionated using peptide IEF, whereby a good correlation between the calculated (theoretical) pI and the experimental pI could be established. This pI calculator permits the implementation of optimal pK values depending on the experimental conditions and a reliable calculation of peptide pI which can be utilized as a filtering technique in validating peptide identifications. Our data reveal that the shift due to a phosphorylation or N‐terminal acetylation is highly dependent on the presence of acidic or basic residues in the peptide. Furthermore, using this pI calculator, we revealed previously unknown position‐specific pKs of asparagine and carbamidomethylated cysteine depending on their location in the peptide. Collectively, this peptide pI calculator is a welcome addition to the versatility and robustness of IEF for the separation and confident identification of (post‐translationally modified) peptides.
Difference gel electrophoresis
Authors: Timms John F. , Cramer Rainer
Published: November 2008

DIGE is a protein labelling and separation technique allowing quantitative proteomics of two or more samples by optical fluorescence detection of differentially labelled proteins that are electrophoretically separated on the same gel. DIGE is an alternative to quantitation by MS‐based methodologies and can circumvent their analytical limitations in areas such as intact protein analysis, (linear) detection over a wide range of protein abundances and, theoretically, applications where extreme sensitivity is needed. Thus, in quantitative proteomics DIGE is usually complementary to MS‐based quantitation and has some distinct advantages. This review describes the basics of DIGE and its unique properties and compares it to MS‐based methods in quantitative protein expression analysis.
Stable isotopic labeling in proteomics
Authors: Gevaert Kris , Impens Francis , Ghesquière Bart , Van Damme Petra , Lambrechts Anja , Vandekerckhove Joël
Published: November 2008

Labeling of proteins and peptides with stable heavy isotopes (deuterium, carbon‐13, nitrogen‐15, and oxygen‐18) is widely used in quantitative proteomics. These are either incorporated metabolically in cells and small organisms, or postmetabolically in proteins and peptides by chemical or enzymatic reactions. Only upon measurement with mass spectrometers holding sufficient resolution, light, and heavy labeled peptide ions or reporter peptide fragment ions segregate and their intensity values are subsequently used for quantification. Targeted use of these labels or mass tags further leads to specific monitoring of diverse aspects of dynamic proteomes. In this review article, commonly used isotope labeling strategies are described, both for quantitative differential protein profiling and for targeted analysis of protein modifications.