bluuebunny/crossref_metadata_2025 huggingface dataset:
p73 isoforms affect VEGF, VEGF165b and PEDF expression in human colorectal tumors: VEGF165b downregulation as a marker of poor prognosis
Authors: Díaz Raquel , Peña Cristina , Silva Javier , Lorenzo Yolanda , García Vanesa , García José M. , Sánchez Antonio , Espinosa Pablo , Yuste Rosario , Bonilla Félix , Domínguez Gemma
Published: June 2008

The secreted mitogen vascular endothelial growth factor, VEGF, plays a pivotal role in angiogenesis. Hypoxia, inactivation of p53 and oncogenic K‐Ras induce VEGF expression. Other factors such as p73 may also affect VEGF levels. Curiously, p73 may also regulate angiogenesis by affecting the expression of the pigment epithelium‐derived factor, PEDF. Additionally, VEGF might harbor additional functions through the activation of E2F transcription factors. Recently, a new VEGF variant formed by alternative splicing, VEGF165b, has been described as exerting anti‐angiogenic activity. We study here whether p73 isoforms levels ‐TAp73 and ΔTAp73‐ and p53 and K‐Ras status affect the expression of the above‐mentioned angiogenesis‐related genes (through the correlation between their expressions), the prognostic value of VEGF165b and PEDF and the correlation between VEGF and E2F‐1 levels. Tumor and normal tissue of 112 colorectal cancer patients was analyzed to evaluate: (i) levels of TAp73, ΔTAp73, VEGF, VEGF165b, PEDF and E2F‐1 by quantitative real‐time RT‐PCR, (ii) p53 status by immunohistochemistry and (iii) mutations in the first exon of K‐Ras by PCR‐SSCP. Tumor characteristics were examined in each patient. Associations were observed between: (i) specific p73 isoforms and VEGF and VEGF165b expression; (ii) ΔEx2p73 variant and downregulation of PEDF; (iii) VEGF and PEDF expression; (iv) inactive p53 and VEGF165b levels; (v) oncogenic K‐Ras and PEDF downregulation; (vi) E2F‐1 and VEGF expressions; (vii) VEGF165b downregulation and poor prognosis parameters of tumors. We conclude that the levels of p73 isoforms could affect the expression of VEGF, VEGF165b and PEDF. This scenario becomes complicated because a feedback between VEGF and PEDF may exist. VEGF may activate the E2F‐1 factor. Mutations in K‐Ras could negatively regulate PEDF expression. p53 inactivation might result in compensatory mechanisms such as over‐expression of VEGF165b. Our data support the role of VEGF165b as a tumor suppressor factor in colorectal carcinogenesis and its possible prognosis value. © 2008 Wiley‐Liss, Inc.
Genistein selectively potentiates arsenic trioxide‐induced apoptosis in human leukemia cells via reactive oxygen species generation and activation of reactive oxygen species‐inducible protein kinases (p38‐MAPK, AMPK)
Authors: Sánchez Yolanda , Amrán Donna , Fernández Carlos , de Blas Elena , Aller Patricio
Published: June 2008

The observation that genistein may behave as a pro‐oxidant agent lead us to examine the capacity of this isoflavone to modulate the toxicity of the oxidation‐sensitive anti‐leukemic agent arsenic trioxide (ATO), and for comparison other anti‐tumor drugs. Co‐treatment with genistein increased ATO‐provoked apoptosis and activated apoptosis regulatory events (Bcl‐XL down‐regulation, cytochrome c and Omi/HtrA2 release from mitochondria, XIAP decrease and caspase‐8/Bid and caspase‐3 activation) in U937 promonocytes and other human leukemia cell lines (HL60, THP‐1, Jurkat, RPMI‐8866), but not in phytohemagglutinin‐stimulated non‐tumor peripheral blood lymphocytes (PBLs). Genistein, alone and with ATO, stimulated reactive oxygen species generation, and apoptosis was attenuated by N‐acetyl‐L‐cysteine and butylated hydroxyanisole. Addition of low H2O2 concentrations mimicked the capacity of genistein to increase ATO‐provoked apoptosis in leukemia cells, but not in PBLs. By contrast, co‐treatment with genistein or H2O2 failed to potentiate the toxicity of DNA‐targeting agent cisplatin, the proteasome inhibitor MG‐132 and the histone deacetylase inhibitor MS‐275. Within the here used time‐period (14 hr) genistein, alone or with ATO, did not significantly affect Akt phosphorylation and NF‐κB binding activity, nor decreased intracellular GSH content. However, it elicited N‐acetyl‐L‐cysteine‐inhibitable phosphorylation of p38‐MAPK and AMPK, and apoptosis was attenuated by pharmacologic inhibitors against these kinases. The pro‐oxidant capacity of genistein might be exploited to improve the efficacy of ATO as anti‐leukemic agent, and perhaps the efficacy of other oxidation‐based therapeutic approaches. © 2008 Wiley‐Liss, Inc.
Structure and Spatial‐Temporal Dynamics of Chironomidae Fauna (Diptera) in Upland and Lowland Fluvial Habitats of the Chocancharava River Basin (Argentina)
Authors: Principe Romina E. , Boccolini Maricel F. , Corigliano Maria C.
Published: June 2008

Structure of benthic Chironomidae assemblages and their spatial‐temporal dynamic were analyzed in upland and lowland habitats from the Chocancharava River basin (Córdoba, Argentina). Sampling was performed in three tributary streams and in three lowland reaches of the river during high and low rainfall periods. Characteristic taxa of upland and lowland reaches and of the different habitats in these reaches were identified using the IndVal method. Chironomidae assemblages were different between upland and lowland reaches and among habitats in each reach, as assessed by Multiresponse Permutation Procedure and Canonical Correspondence Analyses. Substrate type and current velocity were the major explanatory variables structuring the assemblages in upland reaches whereas in lowland reaches current velocity and aquatic vegetation were the most important variables. The highest richness was found in the most complex habitat units in both upland and lowland stretches as assessed by Analyses of Variance. Chironomidae larvae responded to longitudinal changes of hydraulic variables and to local variations of fluvial habitats at different reaches. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of Emergent and Submerged Macrophytes on the Structure of Planktonic Ciliate Communities in Shallow Freshwater Lakes (Eastern Poland)
Authors: Mieczan Tomasz
Published: June 2008

Data from two shallow macrophyte‐dominated lakes (Eastern Poland) sampled with standardized methods, were evaluated in order to examine the effects of various stands of macrophytes in predicting protozooplankton community structure. Differences in macrophyte structure led to two distinct groups of habitats having different patterns of ciliate distribution. The first group consists of two vegetated habitats of sparse stem density and of the open water zone, and the second of submerged macrophyte species, which were more dense and complex. The number of significant correlations was different in the studied habitats. In central zones of macrophyte habitats the number of ciliates had the strongest correlation with concentrations of total organic carbon and Ptot. On the other side in the border zone a significant correlation between the number of ciliates and the chlorophyll a concentration was found. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Impacts of a Small Dam on Riverine Zooplankton
Authors: Zhou Shuchan , Tang Tao , Wu Naicheng , Fu Xiaocheng , Cai Qinghua
Published: June 2008

In order to explore the temporal impacts of a small dam on riverine zooplankton, monthly samples were conducted from November 2005 to June 2006 in a reach of Xiangxi River, China, which is affected by a small hydropower plant. A total of 56 taxa of zooplankton were recorded during the study and rotifers were the most abundant group, accounting for 97% of total taxa, while the others were copepod nauplii and copepod adults. This study indicated that: (1) the small dam in the Xiangxi River study area created distinct physical and ecological conditions relative to free‐flowing lotic reaches despite the constrained channel and small size of the dam; (2) the existence of the plant's small dam had a significant effect on the zooplankton community. In long periods of drought or dry seasons the effect of the dam on potamoplankton was more pronounced (e.g., November, February, March, and May). But the downfall or the connectivity of channel appeared to decrease the effect of small hydropower plants on riverine zooplankton (e.g., April). The present observation underscores the need for additional studies that provide more basic data on riverine zooplankton communities and quantify ecological responses to dam construction over longer time spans. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis of bioactive ceramic on the titanium substrate by micro‐arc oxidation
Authors: Zhao Zhongwei , Chen Xingyu , Chen Ailiang , Shen Meiling , Wen Shimei
Published: June 2008

Bioactive ceramic films on titanium substrate are prepared successfully by micro‐arc oxidation in electrolyte solution containing NaOH only. The coatings are prepared by micro‐arc oxidation at various applied current densities (200–400 mA/cm2) and in NaOH electrolyte with different concentrations. The XRD shows that they are composed of rutile, anatase, Na2Ti6O13, and Na2Ti4O9 phases. The composition and surface morphologies are strongly dependent on the applied current density and electrolyte concentration. For example, at high current density, the phase is mainly composed of rutile and Na2Ti6O13, and at high electrolyte concentration, it is Na2Ti6O13 phase. The morphologies of the samples vary with the increase of current and electrolyte concentration. The apatite‐inducing ability of bioactive ceramic films is evaluated in biological model fluids. After soaking in biological model fluids, the titania‐based coatings containing Na2Ti6O13 phase have excellent capability of inducing bone‐like apatite. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Decorin moieties tethered into PEG networks induce chondrogenesis of human mesenchymal stem cells
Authors: Salinas Chelsea N. , Anseth Kristi S.
Published: June 2008

A versatile approach to fabricate PEG‐peptide copolymer gels was utilized to design niches to promote chondrogenic differentiation of human mesenchymal stem cells (hMSCs). The sequences RGD and KLER were chosen as motifs to modify PEG gels through a thiol‐acrylate polymerization. The KLER sequence, a binding site from decorin protein, is known to bind strongly to collagen type II and is responsible for matrix organization, while RGD promotes general survival of encapsulated cells. hMSCs were encapsulated at 2 × 106 cells/mL into 10 wt % PEG gels with 1 mM CRGDSG in the presence or absence of 5 mM CKLERG. A scrambled sequence served as a control. The gels were cultured in control and chondrogenic media, containing 5 ng/mL TGFβ1 over a 6‐week period. Cell/gel constructs were analyzed at various time points for glycosaminoglycan (GAG) content, type II collagen deposition, immunostaining, and gene analysis. After 14 days in chondrogenic cultures, cells in RGDS and KLER functionalized gels produced 2.5 times as much GAG/cell as those in gels containing only RGD. By day 28, hMSCs within the chondrogenic KLER gels produced 27‐fold higher hydroxyproline than that of day 0, whereas cells in chondrogenic culture with RGDS alone produced twofold of initial. Immunostained images indicated that col II was more predominant in the KLER‐derivatized gels than others, and enhanced chondrogenic differentiation in KLER containing gels was further supported by RT‐PCR analysis of type II collagen and aggrecan expression. Collectively, these results demonstrate how incorporation of matrix‐binding peptide interacts with hMSCs inducing chondrogenic differentiation and cartilage‐specific ECM deposition. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Development of a fibrin composite‐coated poly(ε‐caprolactone) scaffold for potential vascular tissue engineering applications
Authors: Pankajakshan Divya , Philipose Lizymol P , Palakkal Minshiya , Krishnan Kalliyana , Krishnan Lissy K.
Published: June 2008

Poor cell adhesion, cytotoxicity of degradation products and lack of biological signals for cell growth, survival, and tissue generation are the limitations in the use of a biodegradable polymer scaffold for vascular tissue engineering. We have fabricated a hybrid scaffold by integrating physicochemical characteristics of poly(ε‐caprolactone) (PCL) and biomimetic property of a composite of fibrin, fibronectin, gelatin, growth factors, and proteoglycans to improve EC growth on the scaffold. Solvent cast porous films of poly(ε‐caprolactone) was prepared using PEG as a porogen. Porosity varied between 5 and 200 μm, and FTIR spectroscopy confirmed structural aspects of PCL. Films kept in PBS for 60 days showed tensile strength and elongation matching native blood vessel. Slow degradation of the scaffold was demonstrated by gravimetric analysis and molecular weight determination. Human umbilical vein endothelial cell (HUVEC) adhesion and proliferation on bare films were minimal. FTIR spectroscopy and environmental scanning electron microscopy (ESEM) of PCL‐fibrin hybrid scaffold confirmed the presence of fibrin composite on PCL film. HUVEC was subsequently cultured on hybrid scaffold, and continuous EC lining was observed in 15 and 30 days of culture using ESEM. Results suggest that the new hybrid scaffold can be a suitable candidate for cardiovascular tissue engineering. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Cdk9‐55: A new player in muscle regeneration
Authors: Giacinti Cristina , Musarò Antonio , De Falco Giulia , Jourdan Isabelle , Molinaro Mario , Bagella Luigi , Simone Cristiano , Giordano Antonio
Published: June 2008

Adult skeletal muscle contains a specialized population of myogenic quiescent stem cells, termed satellite cells, which contribute to repair myofibers after injury. During muscle regeneration, satellite cells exit their normal quiescent state, proliferate, activating MyoD and Myf‐5 expression, and finally differentiate and fuse to reconstitute the injured muscle architecture. We have previously reported that cdk9 is required for myogenesis in vitro by activating MyoD‐dependent transcription. In myoblasts induced to differentiate, MyoD recruits cdk9 on the chromatin of muscle‐specific regulatory regions. This event correlates with chromatin‐modifying enzyme recruitment and phosphorylation of cdk9‐specific target residues at the carboxyl‐terminal domain of RNA polymerase II. Here we report that a second cdk9 isoform, termed cdk9‐55, plays a fundamental role in muscle regeneration and differentiation in vivo. This alternative form is specifically induced in injured myofibers and its activity is strictly required for the completion of muscle regeneration process. J. Cell. Physiol. 216: 576–582, 2008, © 2008 Wiley‐Liss, Inc.
Detailing the role of Bax translocation, cytochrome c release, and perinuclear clustering of the mitochondria in the killing of HeLa cells by TNF
Authors: Pucci Bruna , Bertani Francesca , Karpinich Natalie O. , Indelicato Manuela , Russo Matteo A. , Farber John L. , Tafani Marco
Published: June 2008

Induction of cell death in HeLa cells with TNF and cycloheximide (CHX) required an adequate ATP supply and was accompanied by decrease in intracellular pH, translocation of Bax, perinuclear clustering of the mitochondria, and cytochrome c release. The chloride channel inhibitor furosemide prevented the intracellular acidification, the translocation of Bax and the cell death. Cyclosporin A (CyA) or bongkrekic acid (BK) inhibited the induction of the MPT, the release of cytochrome c and the cell death without affecting the perinuclear clustering of the mitochondria or the translocation of Bax. Energy depletion with the ATP synthase inhibitor oligomycin or the uncoupler FCCP in the presence of 2‐deoxy‐glucose prevented the perinuclear clustering of the mitochondria and the cell killing. However, mitochondrial translocation of Bax was still observed. By contrast, cytochrome c was released in the oligomycin‐treated cells but not in the same cells treated with FCCP. The data demonstrate that apoptosis in HeLa cells is ATP dependent and requires the translocation of Bax. The movement of Bax to the mitochondria occurs before and during the perinuclear clustering of these organelles and does not require the presence of ATP. The release of cytochrome c depends on the induction of the mitochondrial permeability transition but not ATP content. J. Cell. Physiol. 217: 442–449, 2008. © 2008 Wiley‐Liss, Inc.
Ovarian stromal blood flow following clomiphene citrate challenge test in infertile women
Authors: Ng Ernest Hung Yu , Tang Oi Shan , Chan Carina Chi Wai , Ho Pak Chung
Published: June 2008

Purpose.

To compare ovarian stromal blood flow indices in the follicular phase and after clomiphene citrate (CC) in infertile women.

Methods.

Pulsatility index (PI), resistance index (RI), and peak systolic blood flow velocity (PSV) of ovarian stromal vessels were determined by spectral Doppler analysis in the early follicular phase and on day 10 after CC. Serum follicle‐stimulating hormone (FSH), luteinizing hormone (LH), and estradiol concentrations were determined.

Results.

A total of 69 infertile women were included in the analysis. No significant differences in the average PI, RI, and PSV of ovarian stromal blood flow were demonstrated in the follicular phase and after CC despite a significant increase in serum estradiol concentration after CC. Serum FSH concentration was similar in the follicular phase and after CC, while serum LH concentration was significantly higher after CC. In the right ovary, ovarian stromal blood flow was absent in 13 (18.8%) patients in the follicular phase and in 6 (8.7%) patients after CC, but the difference did not reach statistical significance. In the left ovary, ovarian stromal blood flow was absent in 13 (18.8%) and 12 (17.4%) patients in the follicular phase and after CC, respectively.

Conclusion.

Ovarian stromal blood flow indices were similar in the follicular phase and after CC. © 2008 Wiley Periodicals, Inc. J Clin Ultrasound, 2008
Generation and validation of affinity reagents on a proteome‐wide level
Authors: Uhlén Mathias , Hober Sophia
Published: June 2008

There is a need for protein‐specific affinity reagents to explore the gene products encoded by the genome. Recently, systematic efforts to generate validated affinity reagents on a whole human proteome level have been initiated. There are several issues for such efforts, including choice of antigen, type of affinity reagent, and the subsequent validation of the generated protein‐specific binders. The advantages and disadvantages with the different approaches are discussed and the problems related to quality assessment of antibodies to be used in multi‐platform applications are addressed. This review also describes the efforts to create a virtual resource of validated antibodies using a community‐based portal and summarizes the status and visions for the publicly available human protein atlas (http://www.proteinatlas.org) showing the human protein profiles in a large number of normal and cancer tissues as well as a large set of human cell lines. Copyright © 2008 John Wiley & Sons, Ltd.
Substitution of amino acid 70 in the hepatitis C virus core region of genotype 1b is an important predictor of elevated alpha‐fetoprotein in patients without hepatocellular carcinoma
Authors: Akuta Norio , Suzuki Fumitaka , Kawamura Yusuke , Yatsuji Hiromi , Sezaki Hitomi , Suzuki Yoshiyuki , Hosaka Tetsuya , Kobayashi Masahiro , Kobayashi Mariko , Arase Yasuji , Ikeda Kenji , Kumada Hiromitsu
Published: June 2008

Previous studies identified amino acid (aa) substitutions of the hepatitis C virus core region of genotype 1b (HCV‐1b core region) and elevated serum alpha‐fetoprotein (AFP) levels as predictors of poor virologic response to pegylated interferon (PEG‐IFN) plus ribavirin (RBV), and also as risk factors for hepatocarcinogenesis. The present study evaluated the impact of aa substitutions of HCV‐1b core region on AFP, as a surrogate marker of hepatocarcinogenesis, on AFP levels in 569 Japanese patients with HCV‐1b but without HCC, and investigated the predictive factors of elevated AFP (≥11 µg/L). High AFP levels were detected in 27.4% of the patients. The rate of hepatocarcinogenesis in a group of 109 patients who received IFN monotherapy and followed‐up for 15 years, was significantly higher in patients with abnormal than normal AFP. Multivariate analysis of 569 patients identified fibrosis stage (F3,4), aspartate aminotransferase (≥76 IU/L), substitution of aa 70 (glutamine or histidine), and platelet count (<15.0 × 104/µl) as significant determinants of elevated AFP. In 49 patients with abnormal AFP levels and substitutions at aa 70 who were treated with PEG‐IFN + RBV, the rate of normalization of AFP was significantly lower in non‐virological responders (28.6%) than in transient (71.4%) and sustained (100%) virological responders. The results indicated that substitution of aa 70 of HCV‐1b core region is an important predictor of elevated AFP in non‐HCC patients, and that eradication of the mutant virus normalizes AFP. The results highlight the importance of eradication of mutant type virus of aa 70 for reducing the risk of hepatocarcinogenesis. J. Med. Virol. 80:1354–1362, 2008. © 2008 Wiley‐Liss, Inc.
Potential of embryonic stem cell‐derived neurons for synapse formation with auditory hair cells
Authors: Matsumoto Masahiro , Nakagawa Takayuki , Kojima Ken , Sakamoto Tatsunori , Fujiyama Fumino , Ito Juichi
Published: June 2008

Recent studies have indicated that embryonic stem cells (ESCs) can be a source for the replacement of spiral ganglion neurons (SGNs), auditory primary neurons, and neurite projections from ESC‐derived neurons to auditory sensory epithelia. However, the potential of ESC‐derived neurons for synapse formation with auditory hair cells (HCs) has not been elucidated. The present study therefore aimed to examine the ability of ESC‐derived neurons to form synaptic connections with HCs in vitro. Mouse ESC‐derived neural progenitors expressing enhanced green fluorescence protein (EGFP) were cocultured with explants of cochlea sensory epithelia obtained from postnatal day 3 mice. After a 7‐day culture, neurites of ESC‐derived neurons predominantly elongated toward inner hair cells (IHCs), which play a crucial role in sound transmission to SGNs. Immunohistochemical analyses revealed the expression of synapsin 1 and synaptophysin in the nerve endings of ESC‐derived neurons adjacent to IHCs, indicating the formation of synaptic connections. Transmission electron microscopy demonstrated synaptic contacts between nerve endings of ESC‐derived neurons and IHCs. The present findings show that ESC‐derived neurons can make synaptic connections with IHCs. © 2008 Wiley‐Liss, Inc.
Flavor quality of fruits and vegetables
Authors: Kader Adel A
Published: June 2008

Fruits and vegetables are important sources of vitamins, minerals, dietary fiber, and antioxidants. The relative contribution of each commodity to human health and wellness depends upon its nutritive value and per capita consumption; the latter is greatly influenced by consumer preferences and degree of satisfaction from eating the fruit or vegetable. Flavor quality of fruits and vegetables is influenced by genetic, preharvest, harvesting, and postharvest factors. The longer the time between harvest and eating, the greater the losses of characteristic flavor (taste and aroma) and the development of off‐flavors in most fruits and vegetables. Postharvest life based on flavor and nutritional quality is shorter than that based on appearance and textural quality. Thus, it is essential that good flavor quality be emphasized in the future by selecting the best‐tasting genotypes to produce, by using an integrated crop management system and harvesting at the maturity or ripeness stage that will optimize eating quality at the time of consumption, and by using the postharvest handling procedures that will maintain optimal flavor and nutritional quality of fruits and vegetables between harvest and consumption. Copyright © 2008 Society of Chemical Industry
Permanganate transfer and reduction by D‐glucose in benzene–cetyltrimethylammoniumbromide aqueous solution: A kinetic study
Authors: Malik Maqsood Ahmad , Khan Zaheer
Published: June 2008

The addition of cationic surfactant, cetlytrimethylammoniumbromide (CTAB), in benzene and aqueous potassium permanganate solution brought the MnO from the aqueous phase to the organic phase. At 525 nm, the absorbance of the organic phase increased until it reached a maximum, and then decreased with [CTAB]. The effect of [CTAB] on the reduction of permanganate by D‐glucose in a benzene–CTAB system has been studied spectrophotmetrically. The observed effect on the rate constant is catalytic up to a certain concentration of CTAB; thereafter, a saturation phenomenon is observed with an increased concentration of CTAB. The oxidation reaction obeyed the first‐order kinetics with respect to the D‐glucose. On addition of H2SO4, there was a decrease in the rate constants. There is evidence for the existence of manganese as a water‐soluble colloidal MnO2. A detailed mechanism with the associated reaction kinetics is presented and discussed. © 2008 Wiley Periodicals, Inc. 40: 496–503, 2008
Effects of fine‐dispersed PTFE on load carrying capacity of PEEK
Authors: Inami Shigeru , Takayanagi Satoshi , Kubo Tomoo , Nanao Hidetaka , Minami Ichiro , Mori Shigeyuki
Published: June 2008

Poly(tetrafluoroethylene) (PTFE)‐blended poly(ether‐etherketone) (PEEK)‐based materials for bearings was evaluated by ring‐on‐disc test equipment. The role of PTFE on load carrying capacities was studied from the viewpoint of tribochemistry. The load carrying capacities of PEEK‐based materials were improved by the addition of PTFE. The dispersion degree of PTFE in PEEK strongly affected the tribological properties. Time‐of‐flight secondary ion mass spectroscopy and X‐ray photoelectron spectroscopy were employed to study the surface chemistry of the rubbed surface. The results indicate that the formation of boundary film composed of PTFE is beneficial to improve load carrying capacities. Copyright © 2008 John Wiley & Sons, Ltd.
Self‐Organization of a Chiral D‐EAK16 Designer Peptide into a 3D Nanofiber Scaffold
Authors: Luo Zhongli , Zhao Xiaojun , Zhang Shuguang
Published: June 2008

Self‐assembling peptide nanofiber scaffolds are an excellent material for applications such as tissue repair, tissue regeneration, instant stopping of bleeding, and slow drug release. We report a new self‐assembling peptide D‐EAK16 consisting purely of D‐amino acids. D‐EAK16 and L‐EAK16 display mirror‐image CD spectra at 20 °C. Like L‐EAK16, D‐EAK16 self‐assembles into nanofibers, thus demonstrating that chiral self‐assembling peptide nanofiber scaffolds can be made from both L‐ and D‐amino acids. We also show that D‐peptide nanofibers are resistant to natural proteases and may thus be useful in biotechnology, nanobiotechnology, tissue repair and tissue regeneration as well as other medical applications.

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Synthesis of Readily Recyclable Biobased Plastics by Diels‐Alder Reaction
Authors: Ishida Kazuki , Yoshie Naoko
Published: June 2008

Readily recyclable biobased plastics were designed and synthesized utilizing the thermally reversible DA reaction. Furyl‐telechelic poly(butylene succinate) prepolymers (PBSF2) were extended with bis‐ and tris‐maleimide linkers (M2 and M3) by the DA reaction in the bulk state to produce linear and network polymers, respectively. The DA reaction was able to proceed at 25–80 °C, at which crystalline domains of PBSF2 were present. In the linear polymer system, the molecular weight in the reaction equilibrium was dependent on the chain length of the prepolymer, but almost independent of the reaction temperature. The cycle of DA and retro‐DA reactions was repeatable with no prepolymer deterioration.

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Synthesis, Characterization, and Photopolymerization of Novel Phosphonated Resins, 2
Authors: Senhaji Omar , Monge Sophie , Chougrani Kamel , Robin Jean‐Jacques
Published: June 2008

New phosphonated cross‐linked polymers were synthesized from telomers obtained by reaction between 10‐undecenol and dialkyl hydrogenphosphonates. Telomers were studied using MALDI‐TOF MS. It was proven that side products were produced, corresponding to cross‐esterification reactions of dialkyl hydrogenphosphonate on telomers and to radical additions of telomer on 10‐undecenol. The same behavior was also observed with allyl alcohol. Telomers were then converted to resins by methacrylation reactions. Finally, photopolymerization of the different resins synthesized was achieved and influence of the nature of the phosphonate group (diester, monoacid and diacid) was also evaluated.

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Time‐Resolved Synchrotron SAXS Observations on Sheared Syndiotactic Poly(propylene) Crystallization Process
Authors: Wen Huiying , Jiang Shichun , Men Yongfeng , An Lijia , Wu Zhonghua , Okuda Hiroshi
Published: June 2008

The in situ crystallization kinetics of syndiotactic poly(propylene) (sPP) has been investigated by synchrotron small‐angle X‐ray scattering (SAXS). The structure evolutions during the isothermal crystallization of sPP with different shear rates have been observed. The results show that shear accelerates the process of crystallization kinetics. Even under low shear rate, the lamellae can be distinctly oriented. In contrast, the lamellar parameters such as the long period, lamellar thickness, and the scattering invariant Q can change obviously only under high shear rate. A mesomorphic structure proposed by Strobl is adopted to elucidate the differences of shear effects with low and high shear rates. Based on all the analysis we are convinced that a relatively stable mesomorphic structure forms before shear is composed and the shear effects on the mesophase will be retained to a certain extent until crystallization is finished.

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Consumer learning and the effects of virtual experience relative to indirect and direct product experience
Authors: Daugherty Terry , Li Hairong , Biocca Frank
Published: June 2008

The Internet has the ability to serve as a more powerful medium than traditional print or broadcast media because consumers are able to interact with products in 3D multimedia environments, thus simulating a new form of experience—a virtual experience. However, very little research has explored the impact of this new type of experience, especially in combination with indirect (advertising) and direct (product trial) experience. Therefore, this study presents the findings from two laboratory experiments designed to empirically test both the single and sequential impact of consumer exposure to indirect, direct, and virtual experiences on brand attitude, product knowledge, and purchase intention when evaluating a digital video camcorder. The results indicate that exposure to a virtual experience preceding both indirect and direct product experience is more effective at influencing brand attitudes. The research proposition is that virtual experience from 3D product visualization is more similar to direct experience than to indirect experience in terms of consumer learning. Implications for business‐to‐consumer Internet marketing and e‐commerce are discussed. © 2008 Wiley Periodicals, Inc.
Click Assisted One‐Pot Multi‐Step Reactions in Polymer Science: Accelerated Synthetic Protocols
Authors: Lundberg Pontus , Hawker Craig J. , Hult Anders , Malkoch Michael
Published: June 2008

Presently, the majority of reports deal with combining chemical reactions, in a stepwise fashion, to obtain well‐defined polymers. In the future, chemists need to address new challenges such as increase in the range of available efficient reactions, developing libraries of compatible one‐pot reactions, and the application of obtained materials in key industries. Indeed, the rising importance of the click concept has now devised robust synthetic approaches in various fields of research. The unique selectivity of the click reaction is today a new found toolbox for scientists to investigate one‐pot multi‐step systems. Several accelerated protocols have elegantly been reported to obtain a library of advanced polymers.

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Effect of Microstructures on the Phase Transition Behavior of P(CL‐GL)‐PEG‐P(CL‐GL) Triblock Copolymer Aqueous Solutions
Authors: Jiang Zhiqiang , You Yujing , Gu Qun , Hao Jianyuan , Deng Xianmo
Published: June 2008

Amphiphilic poly[(ε‐caprolactone)‐co‐glycolide]‐block‐poly(ethylene glycol)‐block‐poly[(ε‐caprolactone)‐co‐glycolide) [P(CL‐GL)‐PEG‐P(CL‐GL)] triblock copolymers with different average lengths of caproyl sequences (LCL) were synthesized by ring‐opening polymerization at different temperatures. A 25% aqueous solution of the copolymer with LCL = 11.0 formed a gel, owing to strong crystallinity‐induced hydrophobicity at low temperature, and underwent a gel‐sol transition (UCST behavior) when the temperature was increased to 40 °C. In contrast, the solution of copolymer with LCL = 6.7 underwent a sol‐gel transition (LCST behavior) due to micelle aggregation. However, a clear sol‐turbid sol phase transition was observed for the copolymer with more random microstructures (LCL = 5.2).

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Psychological features of patients with complex regional pain syndrome type I related dystonia
Authors: Reedijk Wouter B. , van Rijn Monique A. , Roelofs Karin , Tuijl Jolien P. , Marinus Johan , van Hilten Jacobus J.
Published: June 2008

The objective of this study was to evaluate psychological features in severely affected patients with complex regional pain syndrome type I‐ (CRPS‐I) related dystonia. Personality traits, psychopathology, dissociative experiences, the number of traumatic experiences, and quality of life were studied in 46 patients. Findings were compared with two historical psychiatric control groups [54 patients with conversion disorder (CD) and 50 patients with affective disorders (AD)] and normative population data. The CRPS‐I patients showed elevated scores on the measures for somatoform dissociation, traumatic experiences, general psychopathology, and lower scores on quality of life compared with general population data, but had significantly lower total scores on the measures for personality traits, recent life events, and general psychopathology compared with the CD and AD patients. Rates of early traumatic experiences were comparable with the CD and AD patients, and the level of somatoform dissociation was comparable to the CD patients, but was elevated in comparison to the AD patients. Early traumatic experiences were reported in 87% of the CRPS‐I patients and were found to be moderately related to somatoform dissociative experiences, indicating that early traumatic experiences might be a predisposing, although not a necessary factor for the development of CRPS‐I‐related dystonia. Although the psychological profile of the patients with CRPS‐I‐related dystonia shows some elevations, there does not seem to be a unique disturbed psychological profile on a group level. © 2008 Movement Disorder Society
Distribution of motor impairment influences quality of life in Parkinson's disease
Authors: Stewart Kim C. , Fernandez Hubert H. , Okun Michael S. , Jacobson Charles E. , Hass Chris J.
Published: June 2008

We evaluated the relationship between upper extremity (UE) and lower extremity (LE) motor impairments in Parkinson's disease (PD) to overall disability and quality of life (QoL) measures. A total of 639 patients who were diagnosed with idiopathic PD were administered the Unified Parkinson's Disease Rating Scale (UPDRS), QoL, activities of daily living (ADL), and behavioral scales. Composite UE and LE scores from the motor section of the UPDRS were correlated with ADL, QoL, and behavioral measurement scores while controlling for disease duration. Patients with greater UE and LE motor impairments had lower QoL scores. However, LE impairments had a greater influence than UE impairments across all QoL measures. © 2008 Movement Disorder Society
MR spectroscopy in monitoring the treatment of Wilson's disease patients
Authors: Tarnacka Beata , Szeszkowski Wojciech , Golebiowski Marek , Czlonkowska Anna
Published: June 2008

The aim of this study was to determine the effectiveness of brain proton magnetic resonance spectroscopy (1H‐MRS) for monitoring therapy in Wilson's disease (WD) patients. Voxels were located in the globus pallidus (right, left). We followed 17 newly diagnosed WD cases for 1‐year period. During this observation period, 6 neurological and 9 hepatic patients improved, while 2 neurological patients deteriorated. The pretreatment 1H‐MRS analysis showed a statistically significant lower level of mI/Cr, NAA/Cr, and higher Lip/Cr in all WD patients with improvement compared with controls. In patients with hepatic signs, a statistically significant increase of mI/Cr and Glx/Cr was observed in the second (1 year posttreatment) 1H‐MRS. In patients with neurological improvement after treatment in the follow‐up 1H‐MRS, a statistically significant increase of NAA/Cr was noted. During neurological deterioration, a decrease of Glx/Cr and NAA/Cr was seen, in contrast to another neurologically impaired patient with liver failure exacerbation, where a decrease of mI/Cr and increase of Glx/Cr was observed. The alternations of NAA/Cr ratio in neurologically impaired patients and mI/Cr and Glx/Cr in patients with liver failure could be a sensitive marker of the clinical recovery and deterioration in those WD patients. 1H‐MRS is a technique that can be used for accurate monitoring of treatment efficacy in WD patients. © 2008 Movement Disorder Society
A Jacobi spectral Galerkin method for the integrated forms of fourth‐order elliptic differential equations
Authors: Doha Eid H. , Bhrawy Ali H.
Published: June 2008

This article analyzes the solution of the integrated forms of fourth‐order elliptic differential equations on a rectilinear domain using a spectral Galerkin method. The spatial approximation is based on Jacobi polynomials P (x), with α, β ∈ (−1, ∞) and n the polynomial degree. For α = β, one recovers the ultraspherical polynomials (symmetric Jacobi polynomials) and for α = β = ∓½, α = β = 0, the Chebyshev of the first and second kinds and Legendre polynomials respectively; and for the nonsymmetric Jacobi polynomials, the two important special cases α = −β = ±½ (Chebyshev polynomials of the third and fourth kinds) are also recovered. The two‐dimensional version of the approximations is obtained by tensor products of the one‐dimensional bases. The various matrix systems resulting from these discretizations are carefully investigated, especially their condition number. An algebraic preconditioning yields a condition number of O(N), N being the polynomial degree of approximation, which is an improvement with respect to the well‐known condition number O(N8) of spectral methods for biharmonic elliptic operators. The numerical complexity of the solver is proportional to Nd+1 for a d‐dimensional problem. This operational count is the best one can achieve with a spectral method. The numerical results illustrate the theory and constitute a convincing argument for the feasibility of the method. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009
Preparation of Al(OH)3/PMMA nanocomposites by emulsion polymerization
Authors: Park S. Y. , Park E. J. , Lee M. Y. , Park C. , Kim H. G. , Jeong E. D. , Lim K. T.
Published: June 2008

Al(OH)3/PMMA nanocomposites were prepared by the emulsion polymerization of methyl methacrylate (MMA) in the presence of surface‐functionalized Al(OH)3 particles. Nanosized Al(OH)3 particles were previously functionalized with a silane coupling agent, 3‐(trimethoxysilyl) propyl methacrylate (γ‐MPS), which was confirmed by FT‐IR and XRF analysis. The average size of seed particles was around 70 nm, and the density of the coupling agent on the particles was calculated to be 8.9 µmol m−2. The emulsion polymerization was attempted at relatively high solid content of 40–46 wt%. The ratio of the seed particles to MMA had a strong influence on the stability of latex as well as the morphology of composites. Nanocomposites where several PMMA nodules were attached on the surface of Al(OH)3 core were produced with stable latex emulsion when the weight percents of Al(OH)3 to MMA were below 20. In the case of higher ratio of 30%, however, the latexes became unstable with an aggregation, and the product morphology was in the shape of large composite. Thermogravimetric analysis showed an improved thermal stability of PMMA composites with the incorporation of Al(OH)3 nanoparticles. Copyright © 2008 John Wiley & Sons, Ltd.
Structural analysis of α‐Gal and new non‐Gal carbohydrate epitopes from specific pathogen‐free miniature pig kidney
Authors: Kim Yun‐Gon , Gil Geun‐Cheol , Harvey David J. , Kim Byung‐Gee
Published: June 2008

The major barrier in transplantation of pig organs into humans is the presence of surface carbohydrate antigens (e.g., the Galα1‐3Galβ1‐4GlcNAc‐R (α‐Gal) epitope) expressed on pig endothelial cells. In this study, totalN‐glycans from membrane glycoproteins derived from specific pathogen‐free miniature pig kidney are identified by MALDI‐TOF, negative ion ESI MS/MS and normal‐phase HPLC (NP‐HPLC) combined with exoglycosidase digestion. Over 100N‐glycans, including sialylated and neutral types, were identified. As well as the known α‐Gal antigens, some of these glycans contained novel non‐Gal carbohydrate antigens such as (Neu5Gc‐Gal‐GlcNAc) and Galα1‐3Lewisx(Gal‐Gal‐(Fuc)GlcNAc) which have not been reported before inN‐glycans from pig organs. The ability of MALDI, ESI, and HPLC to measure the relative proportions of the glycans was evaluated. The HPLC resolution was insufficient for accurate work and some minor differences were noted in the ionization efficiencies of different glycan groups when measured by the two mass spectrometric techniques. However, the results indicated that the relative quantity of α‐Gal epitope was in the region of 50% of the complex glycans. High‐mannose type glycans were also abundant (35–43%) but appeared to be ionized more efficiently than the complex glycans by ESI than by MALDI.
Functionalized poly(phenylene‐alt‐bithiophenes): Synthesis, chiroptical properties, and interaction with chiral amines
Authors: Vangheluwe Marnix , Verbiest Thierry , Koeckelberghs Guy
Published: June 2008

New functionalized, (a)chiral poly(phenylene‐alt‐bithiophene)s were prepared and their chiroptical properties were studied. The polymers were prepared by a Stille coupling reaction and were functionalized with protected carboxylic acid and amino functions (tert‐butyl ester and BOC respectively). The polymers are present as well conjugated rigid rods in solution, which (chirally) aggregate in nonsolvents and film. In a next step, the protecting group (tert‐butyl ester in case of the carboxylic acid) was removed. Aggregation of this polymer can be induced by addition of amines; if chiral amines are used, the polymer chains chirally stack. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4817–4829, 2008
Syntheses of polyolefin‐based stereoregular diblock copolymers for self‐assembled nanostructures
Authors: Lin Wen‐Fu , Hsiao Ting‐Jui , Tsai Jing‐Cherng , Chung Tsai‐Ming , Ho Rong‐Ming
Published: June 2008

The preparation of polyolefin‐based stereoregular diblock copolymers by postpolymerization of ethenyl‐capped syndiotactic polypropylene‐based propylene/norbornene copolymer (sPP‐based P‐N copolymer) led to the successful generation of a structurally uniform stereoregular diblock copolymer for self‐assembly studies. The ethenyl‐capped prepolymer was prepared by conducting propylene/norbornene copolymerization in the presence of Me2C(Cp)(Flu)ZrCl2/MAO. Ozonolysis of ethenyl‐capped sPP‐based P‐N copolymer provided the formyl group end‐capped, end‐functionalized prepolymer with a quantitative functional group conversion ratio. Subsequently, connecting the formyl end‐group of the stereoregular prepolymer by coupling with living anionic polystyrene resulted in the high yield production of stereoregular diblock copolymer (sPP‐based P‐N‐block‐polystyrene), which is difficult to prepare by other methods. The resulting stereoregular diblock copolymer possesses precise chemical architecture to self‐organize into consistent nanostructures as evidenced by transmission electron microscopy and small angle X‐ray scattering. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4843–4856, 2008
Cognitive effects of chemotherapy in post‐menopausal breast cancer patients 1 year after treatment
Authors: Collins Barbara , Mackenzie Joyce , Stewart Angela , Bielajew Catherine , Verma Shailendra
Published: June 2008

Objective: Studies in breast cancer patients indicate that chemotherapy may cause subtle cognitive disturbances in some women, but the course is unclear. The current study evaluated the cognitive effects of adjuvant chemotherapy in post‐menopausal breast cancer patients 1 year following completion of treatment.

Patients and methods: Breast cancer patients scheduled to receive adjuvant chemotherapy (n=53) completed comprehensive neuropsychological testing before commencing chemotherapy (T1), 1 month after completing chemotherapy (T2), and again 1 year later (T3). A control group of women receiving adjuvant hormonal therapy (n=40) was tested at comparable intervals. A standardized regression‐based approach was used to identify cognitive decline, and incidence of decline was compared across treatment groups.

Results: Whereas at T2, chemotherapy patients were more likely to show cognitive decline than hormonal patients, by T3, the frequency of reliable cognitive decline was the same in both groups (11 and 10%, respectively). However, those chemotherapy patients receiving hormonal therapy at T3 were inferior to the chemotherapy patients not receiving hormonal treatment on composite measures of processing speed and verbal memory.

Conclusion: These data suggest that there is a subtle negative impact of chemotherapy on cognitive function in breast cancer patients shortly following completion of treatment, but that this resolves within 1 year. However, given that our control group comprises breast cancer patients receiving hormonal therapy, and indications that hormonal therapy may also adversely affect cognition, such conclusions must be considered tentative. Copyright © 2008 John Wiley & Sons, Ltd.
First‐principles study of the structural stability and electronic structures of TaN
Authors: Cao C. L. , Hou Z. F. , Yuan G.
Published: June 2008

Using the plane‐wave pseudopotential method within the generalized gradient approximation, we have studied the structural stability and electronic structures for several TaN phases. Our results show CoSn is the calculated ground‐state structure of TaN among the five crystallographic structures that have been studied. The order of energetic stability of phase structures of TaN from low to high is: CsCl < ZnS‐B3 < NaCl < WC < CoSn. The higher stability of TaN in the CoSn and WC structures is due to the formation of pseudogap around the Fermi level and the stronger hybridization between N‐2p states and Ta‐5d states. TaN in all structures studied has a metallic nature. The calculated bulk modulus indicates that TaN in the WC structure may be a less compressible material. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)