bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced skin carcinogenesis and lack of thymus hyperplasia in transgenic mice expressing human cyclin D1b (CCND1b)
Authors: Rojas Paola , Benavides Fernando , Blando Jorge , Perez Carlos , Cardenas Kim , Richie Ellen , Knudsen Erik S. , Johnson David G. , Senderowicz Adrian M. , Rodriguez‐Puebla Marcelo L. , Conti Claudio J.
Published: October 2008

Cyclin D1b is an alternative transcript of the cyclin D1 gene (CCND1) expressed in human tumors. Its abundance is regulated by a single base pair polymorphism at the exon 4/intron 4 boundary (nucleotide 870). Epidemiological studies have shown a correlation between the presence of the G870A allele (that favors the splicing for cyclin D1b) with increased risk and less favorable outcome in several forms of cancer. More recently, it has been shown that, unlike cyclin D1a, the alternative transcript D1b by itself has the capacity to transform fibroblasts in vitro. In order to study the oncogenic potential of cyclin D1b, we developed transgenic mice expressing human cyclin D1b under the control of the bovine K5 promoter (K5D1b mice). Seven founders were obtained and none of them presented any significant phenotype or developed spontaneous tumors. Interestingly, K5D1b mice do not develop the fatal thymic hyperplasia, which is characteristic of the cyclin D1a transgenic mice (K5D1a). Susceptibility to skin carcinogenesis was tested in K5D1b mice using two‐stage carcinogenesis protocols. In two independent experiments, K5D1b mice developed higher papilloma multiplicity as compared with wild‐type littermates. However, when K5D1b mice were crossed with cyclin D1KO mice, the expression of cyclin D1b was unable to rescue the carcinogenesis‐resistant phenotype of the cyclin D1 KO mice. To further explore the role of cyclin D1b in mouse models of carcinogenesis we carried out in silico analysis and in vitro experiments to evaluate the existence of a mouse homologous of the human cyclin D1b transcript. We were unable to find any evidence of an alternatively spliced transcript in mouse Ccnd1. These results show that human cyclin D1b has different biological functions than cyclin D1a and confirm its oncogenic properties. © 2008 Wiley‐Liss, Inc.
Identifying fallers with Parkinson's disease using home‐based tests: Who is at risk?
Authors: Lim Inge , van Wegen Erwin , Jones Diana , Rochester Lynn , Nieuwboer Alice , Willems Anne Marie , Baker Katherine , Hetherington Vicki , Kwakkel Gert
Published: October 2008

The objective of this work is to determine risk factors for falling in patients with Parkinson's disease (PD) using home‐based assessments and develop a prediction model. Data on falls, balance, gait‐related activities, and nonmotor symptoms were obtained from 153 PD patients (Hoehn‐Yahr 2–4) in their home. Fifty‐one candidate determinants for falling were independently tested using bivariate logistic regression analysis. A multivariate logistic regression model was developed to identify patients susceptible to falls. Sixty‐six subjects (43%) were classified as fallers. Eighteen determinants for falling were selected. The final multivariate model showed an accuracy of 74% and included: (1) Freezing of Gait Questionnaire, (2) Timed Get Up and Go (TGUG) score, (3) disease duration, (4) item 15 of the Unified Parkinson's Disease Rating Scale. Based on disease duration, freezing symptoms, walking problems, and a prolonged TGUG duration, assessed in the home situation, it was possible to accurately identify 74% of PD patients as fallers. © 2008 Movement Disorder Society
DFT and multinuclear magnetic resonance studies of diazenedicarboxylates and related compounds
Authors: Mocci Francesca , Usai Michele , Cerioni Giovanni
Published: October 2008

A number of diazenedicarboxylates have been studied by multinuclear magnetic resonance (17O, 15N, 13C) and compared with analogous fumaric, maleic, and phthalic diesters; the investigation of selected compounds of these classes was complemented by density functional theory (DFT) calculations using a polarizable continuum model (PCM) for the solvent, employing the PBE0 functional together with the 6‐311G(d,p) basis set for geometry optimization, and the 6‐311 + G(2d,p) basis set for calculating the NMR shielding using the gauge‐including atomic orbital (GIAO) method. This combined approach provided important information about the preferred conformations in chloroform and their influence on the NMR parameters. Copyright © 2008 John Wiley & Sons, Ltd.
Spatial structure of peptides determined by residual dipolar couplings analysis
Authors: Klochkov Vladimir V. , Baikeev Roustem F. , Skirda Vladimir D. , Klochkov Anton V. , Muhamadiev Farhat R. , Baskyr Igor , Berger Stefan
Published: October 2008

The gated decoupled 13C NMR spectra of a dipeptide (Glu‐Trp) and a tetrapeptide (NAc‐Ser‐Phe‐Val‐Gly‐OMe) were recorded in D2O and in a lyotropic alignment medium (pentaethylene glycol monododecyl ether/n‐hexanol). The residual dipolar couplings were extracted as the differences between the observed couplings for the magnetic nuclei dissolved in the latter and former media. Using a computational optimization, the spatial structures of the compounds were calculated starting from their respective low energy conformations obtained on a semiempirical basis. The uniformity of each conformation was confirmed by the solid‐state 13C NMR spectra of powder samples. Differences between the starting structures and final ones, optimized when employing residual dipolar couplings, are discussed. Copyright © 2008 John Wiley & Sons, Ltd.
Electronic structure and biological activity of chosen DDT‐type insecticides studied by 35Cl‐NQR
Authors: Jadżyn Maciej , Nogaj Bolesław
Published: October 2008

A correlation between the electronic structure and biological activity of chosen dichlorodiphenyltrichloroethane (DDT)‐type insecticides: 1,1,1‐trichloro‐2,2‐bis(4‐chlorophenyl)ethane, 1,1‐dichloro‐2,2‐bis(4‐chlorophenyl)ethane, 2,2‐bis(p‐chlorophenyl)‐1,1‐dichloroethylene, 2,2‐bis(4‐chlorophenyl)ethanoic acid and 4,4′‐dichlorobenzophenone (used in agriculture) has been analysed on the basis of the 35Cl‐nuclear quadrupole resonance (NQR) spectroscopy. The 35Cl‐NQR resonance frequencies measured at 77 K have been correlated with the lethal dose (LD50) parameter that characterises the biological activity of these insecticides. Copyright © 2008 John Wiley & Sons, Ltd.
Complete assignments of 1H and 13C NMR spectral data for three new triterpenoid saponins from Ilex hainanensis Merr.
Authors: Chen Xiao‐Qing , Yang Jie , Liu Xiao‐Xiao , Lai Mao‐Xiang , Wang Qiang
Published: October 2008

Three new oleanane‐type triterpenoid saponins, ilexhainanoside C, D and E, all with 24, 28‐dioic acid groups, were isolated from the leaves of Ilex hainanensis. They were 3β‐hydroxyolean‐12‐ene‐24, 28‐dioic acid‐28‐O‐β‐D‐glucopyranoside(1), 3β, 19α‐dihydroxyolean‐12‐ene‐24, 28‐dioic acid‐28‐O‐β‐D‐glucopyranoside(2) and 3β, 29‐dihydroxyolean‐12‐ene‐24, 28‐dioic acid‐28‐O‐β‐D‐glucopyranoside(3). The structures of these three new compounds were elucidated and complete assignments of the 1H and 13C NMR spectroscopic data were achieved by 1D and 2D NMR experiments [heteronuclear single quantum coherence (HSQC), HMBC and rotational nuclear Overhauser effect spectroscopy (ROESY)]. Copyright © 2008 John Wiley & Sons, Ltd.
Evolution of concepts, development of treatment and growth of concern
Authors: Lader Malcolm
Published: October 2008

The diagnostic criteria for anxiety disorders have changed markedly over the past 50 years and continue to evolve. However, Professor Malcolm Lader, Emeritus Professor of Clinical Psychopharmacology, King's College London, argued in his Keynote Lecture at the Latest Advances in Psychiatry Symposium earlier in the year, that these changes might reflect less conceptual and pathophysiological developments and more perceived treatability. Medical writer, Mark Greener, reports. Copyright © 2008 Wiley Interface Ltd
Therapeutic efficacy of 177Lu‐CHX‐A″‐DTPA‐hu3S193 radioimmunotherapy in prostate cancer is enhanced by EGFR inhibition or docetaxel chemotherapy
Authors: Kelly Marcus P. , Lee Sze Ting , Lee F.‐T. , Smyth Fiona E. , Davis Ian D. , Brechbiel Martin W. , Scott Andrew M.
Published: October 2008

BACKGROUND

This study investigated the biodistribution and therapeutic efficacy of Lutetium‐177 (177Lu) radiolabeled anti‐Lewis Y monoclonal antibody hu3S193 radioimmunotherapy (RIT) in mice bearing prostate cancer xenografts. The ability of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor AG1478 and docetaxel chemotherapy to enhance the efficacy of RIT was also assessed in vivo.

METHODS

The in vitro cytotoxicity of 177Lu labeled hu3S193 on Ley positive DU145 prostate cancer cells was assessed using proliferation assays, with induction of apoptosis measured by ELISA. The in vivo biodistribution and tumor localization of 177Lu‐hu3S193 was assessed in mice bearing established DU145 tumor xenografts. The efficacy and maximum tolerated dose of 177Lu‐hu3S193 RIT in vivo was determined by a dose escalation study. EGFR inhibitor AG1478 or docetaxel chemotherapy was administered at sub‐therapeutic doses in conjunction with RIT in vivo.

RESULTS

177Lu‐hu3S193 mediated significant induction of cytotoxicity and apoptosis in vitro. In vivo analysis of 177Lu‐hu3S193 biodistribution demonstrated specific targeting of DU145 prostate cancer xenografts, with maximal tumor uptake of 33.2 ± 3.9%ID/g observed at 120 hr post‐injection. In RIT studies, 177Lu‐hu3S193 caused specific and dose‐dependent inhibition of prostate cancer tumor growth. A maximum tolerated dose of 350 µCi was determined for 177Lu‐hu3S193. Combination of 177Lu‐hu3S193 RIT with EGFR inhibitor AG1478 or docetaxel chemotherapy both significantly improved efficacy.

CONCLUSIONS

177Lu‐hu3S193 RIT is effective as a single agent in the treatment of Ley positive prostate cancer models. The enhancement of RIT by AG1478 or docetaxel indicates the promise of combined modality strategies. Prostate 69: 92–104, 2009. © 2008 Wiley–Liss, Inc.
Differential age‐associated regulation of clusterin expression in prostate lobes of brown norway rats
Authors: Omwancha Josephat , Anway Matthew D. , Brown Terry R.
Published: October 2008

BACKGROUND

Serum androgen concentrations decline with age in male Brown Norway rats and castration induces apoptosis of luminal secretory epithelial cells in the ventral but not in the dorsal and lateral prostate lobes. Clusterin has been described as an androgen‐repressed gene and a protein with either anti‐ or pro‐apoptotic actions.

METHODS

We measured clusterin mRNA and protein levels, the effects of aging and castration on clusterin protein levels and clusterin immunolocalization within the prostatic ductal network in the prostate lobes of young and aged rats.

RESULTS

Whereas levels of clusterin mRNA and protein expression measured by RT‐PCR and Western blot, respectively, were higher in the ventral and lateral lobes of aged (24 months) compared to young (4 months) rats, no age‐dependent differences were observed in the dorsal lobe. Clusterin expression was localized by immunohistochemistry exclusively to the proximal duct segment of young rats, but extended to the distal segment of the ventral and lateral lobes of aged rats. Despite an age‐related decrease in serum testosterone concentration, clusterin gene expression was not altered in the dorsal lobe. After castration, levels of clusterin expression increased significantly in the ventral and lateral lobes despite the absence of epithelial cell apoptosis in the latter. In castrated rats, clusterin expression extended throughout the proximal–distal duct regions of the prostate lobes of young and aged rats.

CONCLUSION

Regulation of clusterin expression in the prostate lobes of aging rats appears complex and is neither directly repressed by androgen nor dependent on apoptotic‐induced stress. Prostate 69: 115–125, 2009. © 2008 Wiley–Liss, Inc.
PI3K/Akt‐dependent transcriptional regulation and activation of BMP‐2‐Smad signaling by NF‐κB in metastatic prostate cancer cells
Authors: Graham Tisheeka R. , Odero‐Marah Valerie A. , Chung Leland W. , Agrawal Krishna C. , Davis Rodney , Abdel‐Mageed Asim B.
Published: October 2008

BACKGROUND

Bone morphogenetic proteins (BMPs) exert osteoinductive effects in prostate cancer (PC) via uncharacterized mechanisms. In this study, we investigated whether the nuclear transcription factor NF‐κB, implicated in PC metastasis, is involved in transcriptional regulation and activation of BMP‐2 or BMP‐4/Smad signaling in PC cells.

METHODS

NF‐κB inhibition was achieved by IκBα super‐repressor adenoviral vector and activation was monitored by EMSA and reporter assays. BMP expression and activation was measured by PCR and reporter assays. Promoter binding assay was performed by chromatin immunoprecipitation (ChIP) assay. Smad1/5/8 phosphorylation was measured by Western blot analysis.

RESULTS

PCR and chimeric BMP‐2 and BMP‐4 luciferase assays demonstrate that NF‐κB confers robust and selective activation of BMP‐2 in p65 overexpressing or rhTNF‐α‐stimulated PC cells. Inhibition of NF‐κB significantly reduced transcript levels and autocrine production of BMP‐2 by rhTNF‐α stimulated C4‐2B cells and to a lesser extent by the parental LNCaP cells. Selective inhibition of PI3K/Akt suppressed the NF‐κB‐induced BMP‐2 promoter activity. Furthermore, suppression of NF‐κB activation decreased the transcript levels and BMP‐2‐induced phosphorylation of Smad1/5/8, critical downstream targets of BMP‐2 signaling in PC cells. Notably, the activation of BMPRII by BMP‐2 is required for modulation of Smad activation by NF‐κB in PC cells. Based on ChIP analysis, the transcriptional regulation of BMP‐2 gene by NF‐κB may be partially attributed to binding to κb site on the BMP‐2 promoter.

CONCLUSIONS

The data suggest that PI3K/Akt‐NF‐κB axis may promote PC bone metastasis in part by regulating transcription and activation of the BMP‐2‐Smad signaling cascade in osteotropic PC cells. Prostate 69: 168–180, 2009. © 2008 Wiley–Liss, Inc.
History of the Term Prostate
Authors: Josef Marx Franz , Karenberg Axel
Published: October 2008

BACKGROUND

We comprehensively review the history of the word “prostate” and related terms from 600 BC to the present.

METHODS

Both medical and non‐medical ancient texts were searched to clarify the term's etymology and use. Anatomy textbooks of the 16th through the 18th century were analyzed to identify descriptions, illustrations and various expressions used by contemporary authors to designate the prostate.

RESULTS

In ancient Greek the masculine term “prostatēs” meant “president” and was exclusively used in a non‐medical sense. It was not until the Renaissance that anatomists discovered the organ naming it “glandulous body.” In 1600 the French physician du Laurens introduced the metaphoric denomination “prostatae.” However he and his contemporaries misinterpreted the history of the organ and the term, choose the wrong gender when translating it into Latin, and believed that it designated a double organ. Only in the 1800s was this anatomical error corrected while the grammatical one lived on.

CONCLUSIONS

The history of the term “prostate” is a prime example of the difficulties with which the development of a precise urologic terminology had to struggle. At the same time this retrospective view provides a stimulus to avoid linguistic ambiguity in the future. Prostate 69: 208–213, 2009. © 2008 Wiley–Liss, Inc.
C‐terminal tail derived from the neighboring subunit is critical for the activity of Thermoplasma acidophilumD‐aldohexose dehydrogenase
Authors: Nishioka Taiki , Yasutake Yoshiaki , Nishiya Yoshiaki , Tamura Noriko , Tamura Tomohiro
Published: October 2008

The D‐aldohexose dehydrogenase from the thermoacidophilic archaeon Thermoplasma acidophilum (AldT) is a homotetrameric enzyme that catalyzes the oxidation of several D‐aldohexoses, especially D‐mannose. AldT comprises a unique C‐terminal tail motif (residues 247–255) that shuts the active‐site pocket of the neighboring subunit. The functional role of the C‐terminal tail of AldT has been investigated using mutational and crystallographic analyses. A total of four C‐terminal deletion mutants (Δ254, Δ253, Δ252, and Δ249) and two site‐specific mutants (Y86G and P254G) were expressed by Escherichia coli and purified. Enzymatic characterization of these mutants revealed that the C‐terminal tail is a requisite and that the interaction between Tyr86 and Pro254 is critical for enzyme activity. The crystal structure of the Δ249 mutant was also determined. The structure showed that the active‐site loops undergo a significant conformational change, which leads to the structural deformation of the substrate‐binding pocket. Proteins 2009. © 2008 Wiley‐Liss, Inc.
Defining and characterizing protein surface using alpha shapes
Authors: Albou Laurent‐Philippe , Schwarz Benjamin , Poch Olivier , Wurtz Jean Marie , Moras Dino
Published: October 2008

The alpha shape of a molecule is a geometrical representation that provides a unique surface decomposition and a means to filter atomic contacts. We used it to revisit and unify the definition and computation of surface residues, contiguous patches, and curvature. These descriptors are evaluated and compared with former approaches on 85 proteins for which both bound and unbound forms are available. Based on the local density of interactions, the detection of surface residues shows a sensibility of 98%, whereas preserving a well‐formed protein core. A novel conception of surface patch is defined by traveling along the surface from a central residue or atom. By construction, all surface patches are contiguous and, therefore, allows to cope with common problems of wrong and nonselection of neighbors. In the case of protein‐binding site prediction, this new definition has improved the signal‐to‐noise ratio by 2.6 times compared with a widely used approach. With most common approaches, the computation of surface curvature can be locally biased by the presence of subsurface cavities and local variations of atomic densities. A novel notion of surface curvature is specifically developed to avoid such bias and is parametrizable to emphasize either local or global features. It defines a molecular landscape composed on average of 38% knobs and 62% clefts where interacting residues (IR) are 30% more frequent in knobs. A statistical analysis shows that residues in knobs are more charged, less hydrophobic and less aromatic than residues in clefts. IR in knobs are, however, much more hydrophobic and aromatic and less charged than noninteracting residues (non‐IR) in knobs. Furthermore, IR are shown to be more accessible than non‐IR both in clefts and knobs. The use of the alpha shape as a unifying framework allows for formal definitions, and fast and robust computations desirable in large‐scale projects. This swiftness is not achieved to the detriment of quality, as proven by valid improvements compared with former approaches. In addition, our approach is general enough to be applied on nucleic acids and any other biomolecules. Proteins 2009. © 2008 Wiley‐Liss, Inc.
Effect of pressure on helix‐coil transition of an alanine‐based peptide: An FTIR study
Authors: Imamura Hiroshi , Kato Minoru
Published: October 2008

Effects of pressure and temperature on the helix‐coil transition of an alanine‐based peptide (Ac‐ AA(AAKAA)3AAY‐NH2) have been investigated using CD and FTIR spectroscopy. From the correlation between CD and FTIR data, we showed that the change in infrared intensity of the amide I′ band at 1633 cm−1 is almost identical to the change in the helical content calculated from the CD result. Thus, we monitored the amide I′ band intensity at 1633 cm−1 to determine the helical content at high pressures. We determined free energy, enthalpy, and volume changes upon unfolding of the α‐helix. The obtained volume change (0.98 ± 0.04 cm3 mol−1 res−1 at 25.4°C) is not consistent with a recent molecular dynamics simulation study by Pascheck et al. who used temperature‐pressure replica exchange methods (Paschek, Gnanakaran, and Garcia, Proc Natl Acad Sci USA 2005;102:6765–6770). They reported a small negative volume change upon unfolding of the α‐helix, indicating that pressure induced the peptide to unfold. Pressure dependence of the band‐width of the amide I′ band also supported the present experimental results in which pressure induces the peptide to fold, which is also apparently inconsistent with the pressure‐induced protein unfolding that is generally observed. We propose a hypothesis to unravel the paradox of pressure‐induced peptide folding and protein unfolding. Proteins 2009. © 2008 Wiley‐Liss, Inc.
Degradation kinetics and safety evaluation of buprofezin residues in grape (Vitis vinifera L.) and three different soils of India
Authors: Oulkar Dasharath P , Banerjee Kaushik , Patil Sangram H , Upadhyay Ajay K , Taware Praveen B , Deshmukh Madhukar B , Adsule Pandurang G
Published: October 2008

BACKGROUND: This work was undertaken to determine the preharvest interval (PHI) of buprofezin to minimize its residues in grapes and thereby ensure consumer safety and avoid possible non‐compliance in terms of residue violations in export markets. Furthermore, the residue dynamics in three grapevine soils of India was explored to assess its environmental safety.

RESULTS: Residues dissipated following non‐linear two‐compartment first + first‐order kinetics. In grapes, the PHI was 31 days at both treatments (312.5 and 625 g a.i. ha−1), with the residues below the maximum permissible intake even 1 h after foliar spraying. Random sampling of 5 kg comprising small bunchlets (8–10 berries) collected from a 1 ha area gave satisfactory homogeneity and representation of the population. A survey on the samples harvested after the PHI from supervised vineyards that received treatment at the recommended dose showed residues below the maximum residue limit (MRL) of 0.02 mg kg−1 applicable for the European Union. In soil, the degradation rate was fastest in clay soil, followed by sandy loam and silty clay, with a half‐life within 16 days in all the soils.

CONCLUSION: The recommendation of the PHI proved to be effective in minimizing buprofezin residues in grapes. Thus, this work is of high practical significance to the domestic and export grape industry of India to ensure safety compliance in respect of buprofezin residues, keeping in view the requirements of international trade. Copyright © 2008 Society of Chemical Industry
A Dual‐Response Partial Least Squares Regression QSAR Model and its Application in Design of Dual Activators of PPARα and PPARγ
Authors: Ajmani Subhash , Kulkarni Sudhir A.
Published: October 2008

In this paper, an attempt was made to develop a dual‐response Quantitative Structure–Activity Relationship (QSAR) model on a series of 5‐aryl thiazolidinedione and oxazolidinedione derivatives acting as dual activators of PPARα and PPARγ (Peroxisome Proliferator‐Activated Receptors) using partial least squares regression method. Various 2D descriptors were calculated and used in the present analysis. For model validation, the dataset was divided into various training and test sets using both rational and random selection procedures. The developed QSAR models were found to be statistically significant with respect to training (r2>0.8), cross‐validation (q2>0.7), and external validation (pred_r2>0.8). The developed dual‐response model suggests that descriptors such as HBA, HBD, Xlog P, polar surface area play an important role in determining both biological activities. In addition, it allows comparison of the behavior of common subset descriptors toward each activity which may aid in the rational design of novel selective/non‐selective potent molecules.
Stable isotope natural abundance of nitrous oxide emitted from Antarctic tundra soils: effects of sea animal excrement depositions
Authors: Zhu Renbin , Liu Yashu , Li Xianglan , Sun Jianjun , Xu Hua , Sun Liguang
Published: October 2008

Nitrous oxide (N2O), a greenhouse gas, is mainly emitted from soils during the nitrification and denitrification processes. N2O stable isotope investigations can help to characterize the N2O sources and N2O production mechanisms. N2O isotope measurements have been conducted for different types of global terrestrial ecosystems. However, no isotopic data of N2O emitted from Antarctic tundra ecosystems have been reported although the coastal ice‐free tundra around Antarctic continent is the largest sea animal colony on the global scale. Here, we report for the first time stable isotope composition of N2O emitted from Antarctic sea animal colonies (including penguin, seal and skua colonies) and normal tundra soils using in situ field observations and laboratory incubations, and we have analyzed the effects of sea animal excrement depositions on stable isotope natural abundance of N2O. For all the field sites, the soil‐emitted N2O was 15N‐ and 18O‐depleted compared with N2O in local ambient air. The mean δ values of the soil‐emitted N2O were δ15N = −13.5 ± 3.2‰ and δ18O = 26.2 ± 1.4‰ for the penguin colony, δ15N = −11.5 ± 5.1‰ and δ18O = 26.4 ± 3.5‰ for the skua colony and δ15N = −18.9 ± 0.7‰ and δ18O = 28.8 ± 1.3‰ for the seal colony. In the soil incubations, the isotopic composition of N2O was measured under N2 and under ambient air conditions. The soils incubated under the ambient air emitted very little N2O (2.93 µg N2ON kg−1). Under N2 conditions, much more N2O was formed (9.74 µg N2ON kg−1), and the mean δ15N and δ18O values of N2O were −19.1 ± 8.0‰ and 21.3 ± 4.3‰, respectively, from penguin colony soils, and −17.0 ± 4.2‰ and 20.6 ± 3.5‰, respectively, from seal colony soils. The data from in situ field observations and laboratory experiments point to denitrification as the predominant N2O source from Antarctic sea animal colonies. Copyright © 2008 John Wiley & Sons, Ltd.
Accuracy assessment of aerial photographs acquired using lighter‐than‐air blimps: low‐cost tools for mapping river corridors
Authors: Vericat Damià , Brasington James , Wheaton Joe , Cowie Michaela
Published: October 2008

Monitoring river systems with repeat aerial photography is a powerful tool although the temporal resolution of surveys is rarely performed at anything better than annual time‐scales. In recent years, a variety of low‐cost aerial platforms for acquiring aerial photography have emerged. While these economical options may facilitate more frequent repeat surveys, the accuracy of imagery needs further consideration.

The accuracy of imagery obtained from a Lighter‐Than‐Air Blimp is investigated through two simple experiments. The first looks at the geospatial error of aerial photographs derived using five geometric transformation models, and the sensitivity of the photo registration quality to various ground control point (GCP) configurations and densities. At high GCP densities, higher order polynomial transformation models provide the highest quality registrations. However, at more modest GCP densities (i.e. 19–28 GCPs Ha−1), simple aerotriangulation and 2nd order polynomial transformation models perform modestly, resulting in registration errors at standards equal to or better than obtained with conventional aerial photography (e.g. 0.5–1 m). The quality of image registration is highly dependent on the configuration of GCPs. In a second experiment, the practical utility of producing a mosaic of blimp acquired imagery is explored over a kilometre long braided reach. Even at relatively low GCPs densities (e.g. 9 GCPs Ha−1), a mosaiced aerial of the entire reach can be produced of adequate quality to support bar‐scale mapping of patch‐scale features. The survey required less than a single day of field work and laboratory processing, and presents a cost‐effective alternative to traditionally commissioned flights. Copyright © 2008 John Wiley & Sons, Ltd.
Estimation of the error performance objectives for satellite communication systems
Authors: Kim Sooyoung , Yeo Sungmoon , Shin Dongseok , Song Sang Seob
Published: October 2008

We consider the physical layer error performance parameters and design criteria for digital satellite systems established by ITU‐R Recommendation S.1062, where the performance objectives are given in terms of the bit error rate (BER) divided by the average number of errors within a cluster. It is well known that errors on satellite links employing forward error correction (FEC) schemes tend to occur in clusters. The resulting block error rate is the same as if it was caused by randomly occurring bit errors with an error‐event ratio of BER/α, whereαis the average number of errors within a cluster. The factor,α, accounts for the burstiness of the errors and also represents the ratio between the BER and the error‐event ratio. This paper proposes theoretical methods to estimate the factor,α. Using the weight distributions of the FEC codes, we derive a set of expressions for the factor,α, as well as their compact lower bounds. We present lower bounds for various FEC schemes including binary BCH codes, block turbo codes, convolutional codes, and turbo codes. The simulation results show that the proposed lower bounds are good estimates in the high signal‐to‐noise ratio region. Copyright © 2008 John Wiley & Sons, Ltd.
Low‐complexity unambiguous acquisition methods for BOC‐modulated CDMA signals
Authors: Lohan Elena Simona , Burian Adina , Renfors Markku
Published: October 2008

The new M‐code signals of GPS and the signals proposed for the future Galileo systems are of split‐spectrum type, where the pseudorandom (PRN) code is multiplied with rectangular sub‐carriers in one or several stages. Sine and cosine binary‐offset‐carrier (BOC) modulations are examples of modulations, which split the signal spectrum and create ambiguities in the envelope of the autocorrelation function (ACF) of the modulated signals. Thus, the acquisition of split‐spectrum signals, based on the ambiguous ACF, poses some challenges, which might be overcome at the expense of higher complexity (e.g. by decreasing the step in searching the timing hypotheses). Recently, two techniques that deal with the ambiguities of the ACF have been proposed, and they were referred to as ‘sideband (SB) techniques’ (by Betz, Fishmanet al.) or ‘BPSK‐like’ techniques (by Martin, Heirieset al.), since they use SB correlation channels and the obtained ACF looks similar to the ACF of a BPSK‐modulated PRN code. These techniques allow the use of a higher search step compared with the ambiguous ACF situation. However, both these techniques use SB‐selection filters and modified reference PRN codes at the receivers, which affect the implementational complexity. Moreover, the ‘BPSK‐like’ techniques have been so far studied for even BOC‐modulation orders (i.e. integer ratio between the sub‐carrier frequency and the chip rate) and they fail to work for odd BOC‐modulation orders (or equivalently for split‐spectrum signals with significant zero‐frequency content). We propose here three reduced‐complexity methods that remove the ambiguities of the ACF of the split‐spectrum signals and work for both even and odd BOC‐modulation orders. Two of the proposed methods are extensions of the previously mentioned techniques, and the third one is introduced by the authors and called the unsuppressed adjacent lobes (UAL) technique. We argue via theoretical analysis the choice of the parameters of the proposed methods and we compare the alternative methods in terms of complexity and performance. Copyright © 2008 John Wiley & Sons, Ltd.
Microwave depolarization versus rain attenuation on earth space in Malaysia
Authors: Mandeep J. S.
Published: October 2008

The wave propagation experiments using Japanese geostationary satellite Superbird‐C have been performed at the Universiti Sains Malaysia earth station. A relationship between rain depolarization and attenuation, valid for earth‐space path at microwave wavelengths, is presented. Cumulative rain attenuation and cross‐polarization discrimination (XPD) statistics are given for the period of 4 years (2002–2005) at 12.255 GHz. XPD varied from 44 dB at 1% to 16 dB at 0.001% of time the abscissa is exceeded. Comparisons were made with available data sets and with five simple XPD models and the results indicate a good performance by the simple isolation model and the CHU model compared with the others. These results serve as checks on the theoretical models needed for predicting communication system performance in geographical regions especially for equatorial climate where measurements are not available. Copyright © 2008 John Wiley & Sons, Ltd.
Multiphoton microscopic imaging of adipose tissue based on second‐harmonic generation and two‐photon excited fluorescence
Authors: Huang Zufang , Zhuo Shuangmu , Chen Jianxin , Chen Rong , Jiang Xingshan
Published: October 2008

The fresh adipose tissue was investigated by the use of multiphoton microscopy (MPM) based on two‐photon excited fluorescence and second‐harmonic generation (SHG). Microstructure of collagen and adipose cells in the adipose tissue is clearly imaged at a subcellular level with the excitation light wavelengths of 850 and 730 nm, respectively. The emission spectrum of collagen SHG signal and NADH and FAD fluorescence signal can also be obtained, which can be used to quantify the content of collagen and adipose cells and reflect the degree of pathological changes when comparing normal tissue with abnormal adipose tissue in the same condition. The results indicate that MPM has the potential to be applied to investigate the adipose tissue and can be used in the research field of lipid and connective tissues. SCANNING 30, 452–456, 2008. © 2008 Wiley Periodicals, Inc.
The virtuous cycle of discovery and creation of entrepreneurial opportunities
Authors: Zahra Shaker A.
Published: October 2008

Researchers have debated whether entrepreneurial opportunities are discovered or created. However, they have often overlooked the importance of the contextual variables that stimulate, shape, and define the entrepreneurial act. This article focuses on entrepreneurial activities within technology‐based established companies and shows how and why certain contexts are more conducive for discovery, while others promote the discovery and creation of opportunities. The article suggests a virtuous and dynamic cycle where discovery enriches creation which, in turn, fosters the discovery of new opportunities. The focus on the context and key features of entrepreneurial search contributes to the behavioral theory of and the debate on the origins of opportunities. Copyright © 2008 Strategic Management Society.
Selected variation: the population‐level implications of multistage selection in entrepreneurship
Authors: Eckhardt Jonathan T. , Ciuchta Michael P.
Published: October 2008

This article examines the population level implications of microlevel theories of entrepreneurship. The actions of those who seek to organize opportunities, as well as the hurdles that they must overcome to successfully exploit them, give rise to an evolutionary multistage selection process. The article indicates that the consideration of selection events leads to a more complete understanding of the entrepreneurial process and how microlevel theories influence important outcomes in entrepreneurship. Other theoretical and empirical implications of staged selection for research in entrepreneurship are discussed. Copyright © 2008 Strategic Management Society.
Understanding opportunity discovery and sustainable advantage: the role of transaction costs and property rights
Authors: Foss Kirsten , Foss Nicolai J.
Published: October 2008

To add insight in new value creation, opportunity discovery should be integrated with strategic management theory. Based on the resource‐based view and the economics of property rights, we build a framework that accomplishes this. Our key argument is that property rights and transaction costs are important antecedents of opportunity discovery. We identify two mechanisms that establish this influence and examine alternative ways in which knowledge, transaction costs, and property rights influence opportunity discovery and sustainable advantage. Copyright © 2008 Strategic Management Society.
Inside opportunity formation: enterprise failure, cognition, and the creation of opportunities
Authors: Mitchell Ronald K. , Mitchell J. Robert , Smith J. Brock
Published: October 2008

To better understand opportunity creation, we investigate the extent to which recognition of failure impacts the new transaction commitment mindset of entrepreneurs. In a PLS model, we utilize data gathered from a sample of 220 entrepreneurs, and augment these results with an ANOVA analysis that provides a deeper exploration of the theory. In this article, we: (1) elaborate on the critical dimensions that represent a multi‐construct view of the new transaction commitment mindset and describe ways that these dimensions can be measured; (2) examine the extent to which the recognition of new venture failure impacts the new transaction commitment mindset; and (3) explore the implications of the interaction between failure recognition and the new transaction commitment mindset for an entrepreneur's decision to continue or abandon opportunity creation efforts. Our results suggest that recognition of failure does indeed impact the new transaction commitment mindset and, by extension, can enable opportunity creation. Copyright © 2008 Strategic Management Society.
Improved methods for extracting frequent itemsets from interim‐support trees
Authors: Coenen F. , Leng P. , Pagourtzis A. , Rytter W. , Souliou D.
Published: October 2008

Mining association rules in relational databases is a significant computational task with lots of applications. A fundamental ingredient of this task is the discovery of sets of attributes (itemsets) whose frequency in the data exceeds some threshold value. In this paper we describe two algorithms for completing the calculation of frequent sets using a tree structure for storing partial supports, called interim‐support (IS) tree. The first of our algorithms (T‐Tree‐First (TTF)) uses a novel tree pruning technique, based on the notion of (fixed‐prefix) potential inclusion, which is specially designed for trees that are implemented using only two pointers per node. This allows to implement the IS tree in a space‐efficient manner. The second algorithm (P‐Tree‐First (PTF)) explores the idea of storing the frequent itemsets in a second tree structure, called the total support tree (T‐tree); the main innovation lies in the use of multiple pointers per node, which provides rapid access to the nodes of the T‐tree and makes it possible to design a new, usually faster, method for updating them. Experimental comparison shows that these techniques result in considerable speedup for both algorithms compared with earlier approaches that also use IS trees (Principles of Data Mining and Knowledge Discovery, Proceedings of the 5th European Conference, PKDD, 2001, Freiburg, September 2001 (Lecture Notes in Artificial Intelligence, vol. 2168). Springer: Berlin, Heidelberg, 54–66; Journal of Knowledge‐Based Syst. 2000; 13:141–149). Further comparison between the two new algorithms, shows that the PTF is generally faster on instances with a large number of frequent itemsets, provided that they are relatively short, whereas TTF is more appropriate whenever there exist few or quite long frequent itemsets; in addition, TTF behaves well on instances in which the densities of the items of the database have a high variance. Copyright © 2008 John Wiley & Sons, Ltd.
Rheological and Thermal Properties of Extruded Mixtures of Rice Starch and Isolated Soy Protein
Authors: Ramírez Ortiz Maria Eugenia , San Martín‐Martínez Eduardo , Martínez Padilla Laura P.
Published: October 2008

Many foods gain new mechanical, thermal and textural properties after being processed due to interactions between carbohydrates and proteins. This effect is characteristic for each foodstuff. The properties of extruded isolated soy protein (ISP) and rice starch were studied considering the following extrusion variables: starch proportion with respect to ISP (0–100%), pH (3–9), moisture content (20–30%) and temperature (140–180ºC). The following characteristics were measured: Water absorption index (WAI), water solubility index (WSI), glass transition temperature (Tg), melting temperature (Tm), viscosity at 90ºC and at 50ºC, storage (G′), loss modulus (G′′) and tan δ. The results indicate that the extruded starch exhibits higher WAI and WSI values than untreated starch. For extruded ISP these values are much lower than for untreated ISP. Extrudates with higher starch proportion had higher Tg and Tm values; pH has a significant effect (p<0.05), at pH 3 higher Tg values were observed, and at pH 9 higher values of Tm. The highest viscosities at 90ºC and 50ºC were observed for extrudates with a higher starch proportion and pH 9. Extruded mixtures showed a more elastic than viscous behavior and an extruded 1:1 blend of starch‐ISP exhibited the behavior of a viscous liquid.
Effects of Extrusion Temperature and Plasticizers on the Physical and Functional Properties of Starch Films
Authors: Pushpadass Heartwin A. , Marx David B. , Hanna Milford A.
Published: October 2008

Cornstarch, at 20% moisture content (dry basis, d.b.), was mixed with glycerol at 3:1 ratio to form the base material for extruded starch films. Stearic acid, sucrose and urea, at varying concentrations, were tested as secondary plasticizers for the starch‐glycerol mixture. The ingredients were extruded at 110 and 120°C barrel temperatures to determine the effects of extrusion temperature, plasticizer type and their concentrations on the film‐forming characteristics of starch, as well as their effects on selected physical and functional properties of the films. The physical and mechanical properties of the films were studied by scanning electron microscopy (SEM) and tensile testing, while the glass transition and gelatinization properties were analyzed using differential scanning calorimetry (DSC). The interactions between the functional groups of starch and plasticizers were investigated using Fourier‐transform infrared (FTIR) spectroscopy. The water vapor permeability (WVP) properties of starch films were determined using ASTM standard E96‐95. Scanning electron micrographs exhibited the presence of native and partially melted starch granules in the extruded films. The tensile stress, strain at break and Young's modulus of starch films ranged from 0.9 to 3.2 MPa, 26.9 to 56.2% and 4.5 to 67.7 MPa, respectively. DSC scans displayed two glass transitions in the temperature ranges of 0.1 to 1°C and 9.6 to 12°C. Multiple melting endotherms, including that of amylose‐lipid complexes, were observed in the thermoplastic extrudates. The gelatinization enthalpies of the starch in the extruded films varied from 0 to 1.7 J/g, and were dependent largely on the extrusion temperature and plasticizer content. The shift in the FTIR spectral bands, as well as the appearance of double‐peaks, suggested strong hydrogen bonding interactions between the starch and plasticizers. The WVP of starch films ranged from 10.9 to 15.7 g mm h‐1 m‐2 kPa‐1, depending on the extrusion temperature and the type of plasticizer used.
Evaluating the utility of an accelerometer and urinary hormone analysis as indicators of estrus in a Zoo‐housed koala (Phascolarctos cinereus)
Authors: Takahashi Maressa , Tobey Jennifer R. , Pisacane Corinne Bacon , Andrus Chris Hamlin
Published: October 2008

Induced ovulators, such as the koala, do not always have overt signs of estrus, which makes pairing these animals for breeding purposes difficult to achieve in a zoo setting. This study examined the possibility of using alternative methods to behavioral sampling and weight fluctuations for monitoring estrus in a female koala of reproductive age. We attempt to gain an improved understanding of koala estrus and enhance our ability to detect it by combining a noninvasive technique for hormone analysis with a newer method for recording activity level. The findings suggest that activity levels were accurately measured using an accelerometer and increased activity was associated with one estrus behavior, bellowing. Weekly weight declines occur with increases in activity registered from the accelerometer. We also validated an assay to detect progesterone and estradiol in female koala urine in an attempt to detect an estrus spike. However, neither urinary concentrations of estradiol nor progesterone was associated with behavioral cues of estrus in our subject. We suggest that increased female activity, bellowing, and weight loss all indicate a pro‐estrus state that requires proper male stimulation in order to achieve a full estrus display. Zoo Biol 28:59–68, 2009. ©2008 Wiley‐Liss, Inc.
The description concerning foreign affairs and exotic imagination in the fiction of the Ming and Qing dynasties
Authors: Yongqiang LIU
Published: October 2008

The description concerning the foreign affairs and exotic imagination in the vernacular fiction of the Ming and Qing dynasties, in a way, reveal the Chinese people’s vision of the world, which does not only lend a vivid note on the contemporaneous Sino-foreign relationship and its challenge to the traditional society, but also provides an interesting proof for attesting the “others’ perspective” found at the core of contemporary culture theory. This text expounds the historical and cultural contexts of such description and imagination, especially those of Korea, Japan, Vietnam and Thailand. It makes clear that the exotic areas described in fiction do not necessarily equal to those of real countries existing now. Only after the Qing dynasty, did Chinese fiction begin to give clear features of foreign countries and fully exhibit their literary values. So the change of exotic imagination is the landmark between ancient and modern fictions.
One hundred years of new Chinese poetry
Authors: Mian XIE
Published: October 2008

The late Qing revolution saw the rise of the Poetic Revolution. Although its proponents did not succeed in breaking away from the constraints of the prosody of old poetry, the Poetic Revolution paved the way for the May Fourth New Poetry Revolution. The new poetry of the Poetic Revolution was produced against the background of the Opium War, and this historical context determined its goals and values. Ultimately, the emphasis it gave to how new poetry could serve Chinese society proved the stumbling block in its development. New poetry was caught in a conflict between form and content, between tradition and modernity, between the West and China, and between the prosody of classical “old poetry” and the free verse of new poetry.
The dreams and reality of “urban strangers”
Authors: Fan DING
Published: October 2008

Since 1990s, the phenomenon of the urbanization has determined the shift of focus in the creation of Chinese local novels. In the cultural conflicts between agricultural civilization, industrial civilization and post industrial civilization, the connotation of Chinese local literature have extended to reflect the life of farmers who have walked out their hometown and worked in the city. This topic has become an unneglectable resource for Chinese writers. At the same time, to reflect the wandering state of the body and soul of migrant workers also enlarged the border of local literature.