bluuebunny/crossref_metadata_2025 huggingface dataset:
Tetra‐ and Triphosphane Pyridine Podands and Their Cobalt(II) and Nickel(II) Complexes
Authors: Kohl Stephan W. , Heinemann Frank W. , Hummert Markus , Weißhoff Hardy , Grohmann Andreas
Published: August 2006

The reaction of the 2,6‐diethylpyridine‐derived tetraphosphane ligand C5H3N[CMe(CH2PMe2)2]2 (1Me) with nickel(II) or cobalt(II) perchlorate or tetrafluoroborate in methanol produces complexes of approximate square‐pyramidal geometry (NP4 coordination). The nickel complexes are diamagnetic, with NMR spectral features (31P) that reflect a tetrahedral distortion of diametrically opposite phosphorus donors; this is also found in the solid state. In terms of bond lengthsand angles, all complexes differ significantly from theiranalogues containing the phenyl‐substituted ligand C5H3N[CMe(CH2PPh2)2]2. The ligand 1Me is readily and completely oxidised to the corresponding tetrakis(phosphane oxide) upon reaction with NO. Slow oxidation of the cobalt(II) tetrafluoroborate complex of 1Me with aerobic oxygen in acetonitrile produces a trinuclear cobalt complex containing two equivalents of partially oxidised ligand (C2‐symmetrical; donor set: [PMe2]2[P(O)Me2]2). Four phosphane oxide oxygen atoms coordinate the central cobalt(II) ion in tetrahedral fashion, whereas the lateral cobalt(II) ions are in a square‐pyramidal environment provided by two PMe2 donors and three acetonitrile ligands in each case. The reaction of the cobalt(II) perchlorate complex of 1Me with carbonmonoxide gives an octahedral, 19‐valence‐electron dicarbonyl complex in which one of the dimethylphosphanyl groups is uncoordinated. A structural relative of 1Me, C5H3N[CMe(CH2PMe2)2][CMe2(CH2PMe2)] (2), which contains one fewer dimethylphosphanyl donor, can be prepared in a straightforward manner from 2‐ethyl‐6‐isopropylpyridine in a four‐stage process. In a series of mononuclear nickel(II) complexes, 2 employs only its three phosphane donors which, together with a monodentate ligand (acetonitrile, acetamide, or bromide), provide a tetragonal coordination environment for the metal ion which is intermediate between square planar and tetrahedral. The acetamide complex is generated from the acetonitrile complex by slow hydrolysis of the coordinated ligand. Full spectroscopic details for the complexes, as well as X‐ray structure analyses, are reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
An Improved Synthesis of 3,4‐(Aminomethano)proline and Its Incorporation into Small Oligopeptides
Authors: Brackmann Farina , Colombo Noemi , Cabrele Chiara , de Meijere Armin
Published: August 2006

Starting from the readily available Garner aldehyde, a new synthesis of diastereomerically and enantiomerically pure 3,4‐(aminomethano)prolinol (2R,1′S,3S,4S)‐17 has been developed using simple and easily scalable transformations. The protected diamino alcohol (2R,1′S,3S,4S)‐17 has been shown to be an appropriate compound for the exchange of protecting groups. Final Jones oxidation furnished the correspondingly protected diamino acids in high yields. The newly synthesized Fmoc/Boc‐protected 3,4‐(aminomethano)proline (Amp) derivatives, which are proline mimics as well as bicyclic γ‐amino acids, depending on the orthogonal protecting group pattern, were employed for solid‐phase peptide synthesis with the Fmoc strategy. Thus, the features of Amp as a γ‐amino acid residue (γ‐Amp) were investigated in the preparation of alternating α/γ‐amino acid sequences. The obtained highly homogeneous products were characterized by circular dichroism spectroscopy. The fact that the dichroic properties of the α/γ‐oligopeptides were independent from the solvent used (water or methanol) suggests the presence of a preferred conformation. These results are encouraging for the development of foldamers based on γ‐Amp units. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Activation Parameters for the Epoxidation of Substituted cis/trans Pairs of 1,2‐Dialkylalkenes by Dimethyldioxirane
Authors: Crow Brian S. , Winkeljohn W. Rucks , Navarro‐Eisenstein Angela , Michelena‐Baez Elba , Franklin Paul J. , Vasquez Pedro C. , Baumstark Al
Published: August 2006

The first activation parameter data for the reaction of dimethyldioxirane (1) with five cis/trans pairs of alkenes are reported. The epoxidation of cis‐1,2‐dialkylalkenes (2cis: R1 = Me, R2 = iPr; 3cis: R1 = Me, R2 = tBu; 4cis: R1 = R2 = Et; 5cis: R1 = Et, R2 = iPr; 6cis: R1 = Et, R2 = tBu) and trans‐1,2‐dialkylalkenes (2trans: R1 = Me, R2 = iPr; 3trans: R1 = Me, R2 = tBu; 4trans: R1 = R2 = Et; 5trans: R1 = Et, R2 = iPr; 6trans: R1 = Et, R2 = tBu) by 1 produced the corresponding epoxides, quantitatively and stereospecifically, as the sole observable products. Activation parameters of the epoxidation of the five pairs of alkenes, 2cis–6cis and 2trans–6trans, by 1 were determined using the Arrhenius method. Enhanced selectivity for cis‐ vs. trans‐alkene epoxidation was observed at lower temperatures. In general, the ΔG‡ terms were larger and showed more variability for the reaction of 1 with trans‐alkenes as compared to those for the corresponding cis isomers. The ΔH‡ terms mirrored trends observed in ΔG‡ because ΔS‡ terms for all ten of the compounds were roughly identical. The ΔΔG‡ values, a comparison of the trans to the cis isomer data, yielded positive values of 1.2 to 1.8 kcal/mol for the five sets of data and appeared to be dependent on relative steric interactions. The experimental activation parameter data, consistent with predictions from ab initio calculations based on a spiro transition‐state model, showed that the lower reactivity of trans‐alkenes is due to enthalpy factors. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
PtCl2‐ and PtCl4‐Catalyzed Cycloisomerization of Polyunsaturated Precursors
Authors: Marco‐Contelles José , Arroyo Nieves , Anjum Shazia , Mainetti Emily , Marion Nicolas , Cariou Kevin , Lemière Gilles , Mouriès Virginie , Fensterbank Louis , Malacria Max
Published: August 2006

The PtCl2‐ and PtCl4‐catalyzed cycloisomerization of polyunsaturated precursors with different O‐protecting groups at the propargylic position is reported. The free hydroxy, O‐(bromomethyl)dimethylsilyl, O‐methyl and O‐propenyl derivatives 1a–f have afforded mixtures of skeletal rearrangement products and/or polycyclic molecules incorporating a cyclopropyl ring system in variable chemical yields. Other parameters such as the variation of the alkenyl chains and the triple‐bond substitution have been examined and gave new mechanistic elements. Very interestingly, for analogous compounds containing an ester moiety, such as the O‐4‐nitrobenzoyl or acetate group (1g–j, and 22) bicyclo[4.1.0]hept‐2‐enyl derivatives were obtained in good yields. These products are formally the result of a 1,2‐migration of an O‐acyl group, coupled to a cyclopropanation step. Related propargylic acetates with a pendant aromatic group (25) or substituted at the terminal acetylenic carbon with a methoxycarbonyl group (24) did not afford this class of rearranged compounds. This type of reaction seems restricted to propargylic derivatives, because the suitably functionalized homopropargylic acetate 24 only afforded 1,3‐dienes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
H.264/AVC prediction modules complexity analysis
Authors: Ayed Mohamed Ali Ben , Samet Amine , Masmoudi Nouri
Published: August 2006

In this paper we study the computational complexity of the intra/inter prediction modules for video coding software according to H.264/AVC standard. We analyse separately the complexity of each mode toward an implementation on TMS320C64 platform. Since any real‐time implementation is considered to be time and money consuming, complexity pre‐analysis of any giving video‐coding algorithm is very important to determine not only software bottlenecks, but also the minimum hardware resources and characteristics required for the targeted platform. To estimate the total complexity of the prediction processes (intra/inter), we assume that the encoder tests all modes. The total cycle's account is estimated by multiplying the number of cycles of each mode by the number of macroblocks in the frame. Simulation results indicate that our methodology for the complexity analyses for H.264/AVC prediction modules provides a good approximation with respect to the experimental results. Copyright © 2006 AEIT.
Pterosaur assemblages of the Jehol Biota and their implication for the Early Cretaceous pterosaur radiation
Authors: Xiaolin Wang , Zhonghe Zhou
Published: August 2006

The Early Cretaceous Jehol Biota from northeast China is well known for many beautifully preserved feathered dinosaurs, early birds and angiosperms. A great number of pterosaurs have also been discovered from the same deposits in recent years, representing arguably the best pterosaur assemblage from the Lower Cretaceous. Two pterosaur assemblages are recognized from the Jehol Biota, and represent two major adaptive radiations in the Early Cretaceous. The first radiation was preserved mainly in the Yixian Formation, and shows a strong resemblance to the Upper Jurassic pterosaur radiation in the Solnhofen Limestone of Germany. The second radiation was preserved in the Jiufotang Formation, with many of its taxa much similar to those of the pterosaur assemblages from the Lower Cretaceous Santana Formation of Brazil. Recent biostratigraphic work and radiometric datings of the Yixian and Jiufotang formations have provided a reliable geochronologic framework for the Jehol pterosaur radiations. The two major radiations occurred at about 125 Ma and 120 Ma, respectively. The radiations of the Jehol pterosaurs are characterized by a remarkable taxonomic diversity, great variation in body size, significant dietary differentiation, and occupancy of diverse niches. The appearance of several biological novelties was also critical in the success of the Jehol pterosaur radiations. The adaptive radiation of the Jehol pterosaurs was obviously coupled with the competition or co‐evolution with many other groups of the Jehol Biota. Among the flying animals in the Jehol Biota, pterosaurs were the major competitors for niches and food with birds. Although the Jehol pterosaurs probably fed mainly on fishes, the co‐evolution between plants and pterosaurs in the Jehol Biota might also have played a significant role in the pterosaur radiations, as is the case for plants and insects, birds, mammals and dinosaurs. Copyright © 2006 John Wiley & Sons, Ltd.
An introduction to Ordovician bivalves of southern China, with a discussion of the early evolution of the Bivalvia
Authors: Zong‐Jie Fang
Published: August 2006

This paper introduces the Ordovician bivalves of southern China to non‐Chinese colleagues, and then incorporates them into the global Ordovician bivalve database compiled by Cope (2004). This will provide a firmer basis for the discussion of the initial adaptive radiation of the Bivalvia. A new scenario for the early evolution of the class Bivalvia is advanced herein based on the integration of a wide variety of evidence concerning bivalves, including morphological features, ontogenetic trajectory, benthic environment and lithologic setting, so as to explain reasonably why the initial explosive radiation of bivalves in the Early Ordovician followed a long‐term macroevolutionary lag since their first appearance during the Cambrian explosion. The early evolution of the Bivalvia can be divided into three phases: (a) the origination and macroevolutionary lag phase in the Early and Middle Cambrian; (b) the crisis phase in the Late Cambrian; and (c) the Ordovician radiation phase, which can be subdivided into two radiation pulses or intervals (the Arenig and the Caradoc radiation intervals). It is the Cambrian substrate revolution that caused a transformation of shallow subtidal seafloors from more coherent Neoproterozoic‐style matgrounds to soupier Phanerozoic‐style mixgrounds, thus compelling Cambrian ‘archetype’ bivalves to sink into the infaunal realm and to adapt themselves to the development of the mixed layer in siliciclastic soft substrate environments. As a result, Cambrian ‘archetype’ bivalves entered a tight bottleneck and became extinct while the latest common ancestor of ‘modern‐type’ bivalves originated from a certain founder population somewhere in the Gondwanan shelf seas. The rapidly evolving founder population may be the place of origin of evolutionary novelties and it became the starting point of the evolution of ‘modern‐type’ bivalves. The macroevolutionary lag of the Bivalvia ended in the earliest Ordovician as a result of the successful invasion of the infaunal adaptive zone. The bivalve die of ‘modern‐type’ was cast during the Ordovician, when all principal clades and all four principal life‐habit groups underwent initial development. A series of morphological innovations, especially the evolution of the muscular hydraulic foot with burrowing adaptations, byssus, and feeding gill, are responsible for the initial adaptive radiation. It is these morphological innovations that provide evolutionary access to the new adaptive zone for bivalves. Copyright © 2006 John Wiley & Sons, Ltd.
Molecular determinants of irinotecan efficacy
Authors: Vallböhmer Daniel , Iqbal Syma , Yang Dong Yun , Rhodes Katrin E. , Zhang Wu , Gordon Michael , Fazzone William , Schultheis Anne M. , Sherrod Andy E. , Danenberg Kathleen D. , Lenz Heinz‐Josef
Published: August 2006

Molecular markers predicting the efficacy of CPT‐11 based chemotherapies in patients with colorectal cancer (CRC) are unknown. Therefore, we investigated whether mRNA levels of drug targets (Topoisomerase I, TS), enzymes involved in 5‐FU metabolism (DPD), in angiogenesis (EGFR, IL‐8, VEGF) and in DNA‐repair/drug detoxification (ERCC1, GST‐P1) are associated with the clinical outcome of patients with CRC treated with first‐line CPT‐11 based chemotherapy. Thirty three patients with metastatic CRC were included in the study. Intratumoral gene expression levels were assessed from paraffin‐embedded tissue samples, using laser capture microdissection and quantitative Real‐Time PCR. Complete response was observed in 1 patient, partial response in 12 patients, stable disease in 13 patients and progressive disease in 6 patients. Response was inevaluable for 1 patient. Patients with complete response or partial response were classified as responders, while patients with stable disease or progressive disease were classified as nonresponders. High intratumoral mRNA levels of EGFR, ERCC1 and GSPT‐P1 were each significantly associated with response to CPT‐11 based chemotherapy. Recursive partitioning analysis showed that mRNA levels of EGFR and ERCC1 are primarily responsible for delineating responders from nonresponders. Also, the combination of high intratumoral gene expression levels of both EGFR and ERCC1 was significantly associated with progression‐free survival. The mRNA levels of EGFR had a significant correlation with expression levels of ERCC1, GST‐P1 and VEGF. This small retrospective study suggests that gene expression levels of EGFR, ERCC1 and GST‐P1 may be useful in predicting the clinical outcome of patients with metastatic CRC treated with first‐line CPT‐11 based chemotherapy. © 2006 Wiley‐Liss, Inc.
Cellular telephones and non‐Hodgkin lymphoma
Authors: Linet Martha S. , Taggart Theresa , Severson Richard K. , Cerhan James R. , Cozen Wendy , Hartge Patricia , Colt Joanne
Published: August 2006

Dramatic increase in hand‐held cellular telephone use since the 1980s and excess risk of lymphoproliferative malignancies associated with radio‐frequency radiation (RFR) exposures in epidemiological and experimental studies motivated assessment of cellular telephones within a comprehensive US case–control investigation of non‐Hodgkin lymphoma (NHL). A questionnaire ascertained cellular telephone use in 551 NHL cases and 462 frequency‐matched population controls. Compared to persons who had never used cellular telephones, risks were not increased among individuals whose lifetime use was fewer than 10 (odds ratio (OR) = 0.9, 95% confidence intervals (CI): 0.6, 1.3), 10–100 (OR = 1.0, 95 % CI: 0.7, 1.5) or more than 100 times (e.g., regular users, OR = 0.9, 95% CI: 0.6, 1.4). Among regular users compared to those who had never used hand‐held cellular telephones, risks of NHL were not significantly associated with minutes per week, duration, cumulative lifetime or year of first use, although NHL was non‐significantly higher in men who used cellular telephones for more than 8 years. Little evidence linked use of cellular telephones with total, diffuse large B‐cell lymphoma or follicular NHL. These findings must be interpreted in the context of less than 5% of the population reporting duration of use of 6 or more years or lifetime cumulative use of 200 or more hours. © 2006 Wiley‐Liss, Inc.
Anticancer effects of amooranin in human colon carcinoma cell line in vitro and in nude mice xenografts
Authors: Ramachandran Cheppail , Nair P.K. Raveendran , Alamo Arturo , Cochrane Curtis Bruce , Escalon Enrique , Melnick Steven J.
Published: August 2006

Amooranin (AMR), a natural triterpenoid drug isolated and characterized from Amoora rohituka stem bark, is cytotoxic to SW620 human colon carcinoma cell line with an IC50 value of 2.9 μg/ml. This novel compound caused depolarization of mitochondrial membrane and decrease of membrane potential, indicating initial signal of apoptosis induction. The percentage of cells with decreased mitochondrial potential ranged from 7.4% at 1 μg/ml to 60.5% at 100 μg/ml AMR. Flow cytometric analysis of apoptosis using Annexin‐V‐FITC staining showed that the percentage of apoptotic cells ranged from 7.5% at 1 μg/ml to 59.2% at 100 μg/ml AMR. AMR‐induced apoptosis was accompanied by redistribution of cytochrome c from mitochondria to cytosol as well as down regulation of Bcl‐2 and Bcl‐XL proteins in a dose‐dependent manner. SW620 human colon carcinoma xenograft mice treated with AMR showed significant reduction in tumor growth rates compared to saline‐ and doxorubicin‐treated groups. The reduction in tumor growth rate was better in xenografts treated with 2 mg/kg AMR than 5 and 10 mg/kg treated mice. The analysis of global gene expression changes induced by AMR in xenograft tumors by microarray hybridization revealed that several genes involved in energy pathways, transport, apoptosis, immune response, nucleic acid metabolism, protein metabolism, cell growth and/or maintenance, signal transduction and cell communication, were affected by this natural cancer drug. These results suggest that the anticancer properties of AMR in SW620 human colon carcinoma cell line are mediated through its effects on functional genomics, targeting the apoptotic process. © 2006 Wiley‐Liss, Inc.
Green's function study of the one‐electron and shake‐up ionization spectra of unsaturated hydrocarbon cage compounds
Authors: Knippenberg S. , François J.‐P. , Deleuze M. S.
Published: August 2006

The valence one‐electron and shake‐up ionization spectra of stella‐2,6‐diene, stella‐2,6‐dione, bicyclo‐[2.2.2]‐octane‐2,5‐dione, and bicyclo‐[2.2.1]‐heptane‐2,5‐dione have been exhaustively studied, up to the double ionization threshold and beyond, by means of one‐particle Green's function theory. This study is based on calculations employing the outer‐valence Green's function and the third‐order algebraic diagrammatic construction schemes, along with a variety of basis sets. A comparison is made with available ultraviolet (He I) photoelectron and (e, 2e) electron‐impact ionization spectra, with main focus on the identification of spectral fingerprints for cyclic strains and through‐bond π‐conjugation. As a byproduct, our results demonstrate that it is impossible to reliably assign complex (e, 2e) ionization spectra by resorting only to Hartree–Fock or Kohn–Sham orbital energies and to the related electron momentum distributions. © 2006 Wiley Periodicals, Inc. J Comput Chem, 2006
Empowerment in terms of theoretical perspectives: Exploring a typology of the process and components across disciplines
Authors: Hur Mann Hyung
Published: August 2006

A variety of studies on empowerment has been conducted, but there has been no overarching framework available for practitioners and researchers hoping to grasp the process and components of empowerment in a comprehensive manner. This study was designed to provide the overarching framework across theories and disciplines for both academics and practitioners in the field of empowerment. A method of theoretical synthesis was employed in this study. Studies were chosen for review in the article based on the two criteria. First, both books and articles were not limited as long as they included theories on the steps toward empowerment and the cognitive element of empowerment. Second, disciplines were not bounded as they provided ideas for the empowerment process and its cognitive elements. It was found that empowerment might be synthesized into five progressive stages and four cognitive elements in both personal and collective empowerment. © 2006 Wiley Periodicals, Inc.
A mixed‐method analysis of African‐American women's attendance at an HIV prevention intervention
Authors: Pinto R.M. , McKay M.M.
Published: August 2006

Grounded in a model of service utilization, this study conceptualizes attendance of African‐American women at an HIV prevention intervention as associated with influences across three ecological domains—individual, service (program), and social network. First, the texts of responses to semistructured, open‐ended elicitation interviews were analyzed. Survey items that conceptually matched the influences on attendance were then selected for subsequent analyses. In order to assess the contributions of groups of variables in separate domains, three blocks of independent variables were entered in a hierarchical regression. The hierarchical regression revealed that individual domain variables (age, level of education, and perception of racism) accounted for 18% of variance in attendance. After controlling for these variables, program domain variables (use of counseling and staff friendliness) accounted for an additional 7% of variance. The social network domain (influence of friends) did not account for any additional variance. It appears that several factors in different ecological domains may influence attendance at HIV prevention interventions. The modifiable factors found here can be used by researchers and practitioners to improve the attendance of racial and ethnic minority populations, those at most risk for HIV exposure, at prevention interventions. © 2006 Wiley Periodicals, Inc.
Impacts of filial piety on preference for kinship versus public care
Authors: Cheung Chau‐kiu , Kwan Alex Yui‐huen , Ng Sik Hung
Published: August 2006

Elder care can involve the elder's children, other relatives, friends, community, and services sponsored by the government. According to the compensatory view, an individual prefers to rely on only one mode of elder care (i.e., care of elders in society, not just one's parents). In contrast, the complementary view suggests that the individual desires to combine elder care from multiple sources. This view expects that someone who practices filial piety more intensively will display a higher desire for other sources of elder care as well. The present study clarifies the impact of filial piety on desire and preference for kin/friend and government support for elder care in society. Its data came from a random sample survey of Hong Kong Chinese. Results endorse the compensatory view and thus disconfirm the complementary view when filial piety showed a negative effect on desire for other sources of support. Particularly, results reveal a more negative impact of filial piety on desire for other sources of support among people aged 40 years or older. These findings sustain the proposal for promoting filial piety as a way to relieve people's reliance on government support in elder care. © 2006 Wiley Periodicals, Inc.
The Comparative Toxicogenomics Database (CTD): a resource for comparative toxicological studies
Authors: Mattingly C.J. , Rosenstein M.C. , Colby G.T. , Forrest Jr J.N. , Boyer J.L.
Published: August 2006

The etiology of most chronic diseases involves interactions between environmental factors and genes that modulate important biological processes (Olden and Wilson, 2000. Nat Rev Genet 1(2):149–153). We are developing the publicly available Comparative Toxicogenomics Database (CTD) to promote understanding about the effects of environmental chemicals on human health. CTD identifies interactions between chemicals and genes and facilitates cross‐species comparative studies of these genes. The use of diverse animal models and cross‐species comparative sequence studies has been critical for understanding basic physiological mechanisms and gene and protein functions. Similarly, these approaches will be valuable for exploring the molecular mechanisms of action of environmental chemicals and the genetic basis of differential susceptibility. J. Exp. Zool. 305A:689–692, 2006. © 2006 Wiley‐Liss, Inc.
Functions of melanin‐concentrating hormone in fish
Authors: Kawauchi Hiroshi
Published: August 2006

Melanin‐concentrating hormone (MCH) was originally discovered in fish, in which it causes aggregation or concentration of melanin granules in melanophores, thus regulating body color. MCH is a cyclic neuropeptide synthesized as a preprohormone in the hypothalamus of all vertebrates. Mammalian MCH plays an important role as a neurotransmitter or neuromodulator in regulating food intake and energy homeostasis. MCH signaling system may involve in regulating food intake also in fish. This neuropeptide binds to G‐protein‐coupled seven transmembrane receptor[s] to mediate its functions. This article reviews MCH and MCH receptor signaling systems in body color change and food intake in fish.J. Exp. Zool. 305A:751–760, 2006. © 2006 Wiley‐Liss, Inc.
Identification of melanin‐concentrating hormone receptor and its impact on drug discovery
Authors: Saito Yumiko , Maruyama Kei
Published: August 2006

The neuropeptide melanin‐concentrating hormone (MCH) was originally isolated from the pituitary of salmon, in which it causes skin paling. MCH is also found abundantly in mammalian neurons, and has been detected in the lateral hypothalamus and zona incerta, brain regions that are at the center of feeding behavior. Acute central administration of MCH leads to a rapid and significant increase in food intake, while MCH expression changes in states of altered energy balance, such as fasting and obesity. Furthermore, MCH knockout mice tend toward hypophagia and leanness. In 1999, we and four other groups identified an orphan G‐protein‐coupled receptor (GPCR) as a specific receptor for MCH (MCH‐1 receptor). Although a second MCH receptor (MCH‐2 receptor) was isolated in humans, it was found to be non‐functional or encode a non‐functional pseudogene in non‐human species, including rodents. The discovery of these MCH receptors permitted the launch of a broad array of drug screening efforts and three MCH‐1 receptor antagonists were identified to reduce food intake and body weight. Interestingly, some antagonists unexpectedly produced evidence that blockade of these receptors has antidepressant and anxiolytic activities. The expressions of the MCH receptors, which have been implicated in regulating emotion, stress and motivation, make MCH an excellent candidate for integrating the various homeostatic stimuli necessary for maintaining the proper conditions of energy metabolism and other physiological functions. Finally, the speed at which MCH receptor studies have been undertaken exemplifies the impact that this deorphanized GPCR will have on setting the stage for more detailed physiological studies.J. Exp. Zool. 305A:761–768, 2006. © 2006 Wiley‐Liss, Inc.
Evaluation of DNA vaccination with recombinant adenoviruses using bioluminescence imaging of antigen expression: impact of application routes and delivery with dendritic cells
Authors: Schweichel Dirk , Steitz Julia , Tormo Damia , Gaffal Evelyn , Ferrer Aleix , Büchs Stefanie , Speuser Petra , Limmer Andreas , Tüting Thomas
Published: August 2006

Recombinant DNA vaccines are able to induce strong CD8+ T cell mediated immunity and have become increasingly attractive for the prevention and treatment of infectious diseases and cancer. Dendritic cells (DC), which critically control cellular immune responses, have been transduced with antigen ex vivo and used as ‘nature's adjuvant’ to enhance vaccine efficacy. The impact of the application route on the in vivo distribution of antigen and the stimulation of CD8+ T cells have been subjects of considerable debate. Here we report the construction of vectors expressing a fusion protein between EGFP, the H2‐Kb‐binding peptide OVAaa257−264 and green click beetle luciferase as a model antigen which allows for simultaneous quantitative assessment of antigen expression using fluorescence and bioluminescence imaging in correlation with CD8+ T cell stimulation in vivo. We applied this construct to evaluate DNA vaccination with recombinant adenoviral vectors, assess the impact of using cultured DC for vaccine delivery and investigate different application routes. Antigen expression was non‐invasively followed in vivo by visualizing bioluminescence with an ultrasensitive CCD camera. CD8+ T cell stimulation was detected with H2‐Kb‐OVAaa257−264 tetramers. We found that intravenous injection of adenovirus‐transduced DC stimulated the strongest OVAaa257−264‐specific cytotoxic T‐lymphocyte (CTL) responses although it delivered two orders of magnitude less antigen in vivo when compared to direct injection of recombinant adenovirus. We believe that our experimental approach has the potential to facilitate translational development of improved genetic immunization strategies targeting DC directly in vivo. Copyright © 2006 John Wiley & Sons, Ltd.
Murine neocortical histogenesis is perturbed by prenatal exposure to low doses of bisphenol A
Authors: Nakamura Keiko , Itoh Kyoko , Yaoi Takeshi , Fujiwara Yasuhiro , Sugimoto Tohru , Fushiki Shinji
Published: August 2006

Bisphenol A (BPA) has been shown to disrupt thyroid hormone function. We therefore studied whether prenatal exposure to low‐doses of BPA affects the morphology and the expression of some genes related to brain development in the murine fetal neocortex. Pregnant mice were injected subcutaneously with 20 μg/kg of BPA daily from embryonic day 0 (E0). Control animals received vehicle alone. For evaluating cell proliferation, neuronal differentiation and migration, bromodeoxyuridine (BrdU) was injected intraperitoneally into pregnant mice with various regimens and the brains were processed for immunohistochemistry. The total RNA was extracted from the embryonic telencephalon at various embryonic stages. The BrdU‐labeled cells examined 1 hour after BrdU injection showed no differences between the BPA‐treated and control groups (n = 10, each), which indicated that the proliferation of precursor cells was not affected. The BrdU‐labeled cells, analysed 2 days after BrdU injection, were decreased in the ventricular zone of BPA‐treated mice at E14.5 and E16.5, whereas they were increased in the cortical plate at E14.5 as compared with those in control mice (n = 10, each). Furthermore, the expression of Math3, Ngn2, Hes1, LICAM, and THRα was significantly upregulated at E14.5 in the BPA‐treated group. These results suggested that BPA might disrupt normal neocortical development by accelerating neuronal differentiation/migration. © 2006 Wiley‐Liss, Inc.
Elastographic imaging of strain distribution in the anterior cruciate ligament and at the ligament–bone insertions
Authors: Spalazzi Jeffrey P. , Gallina Jason , Fung‐Kee‐Fung Simon D. , Konofagou Elisa E. , Lu Helen H.
Published: August 2006

The anterior cruciate ligament (ACL) functions as a mechanical stabilizer in the tibiofemoral joint, and is the most commonly injured knee ligament. To improve the clinical outcome of tendon grafts used for ACL reconstructions, our long‐term goal is to promote graft–bone integration via the regeneration of the native ligament–bone interface. An understanding of strain distribution at this interface is crucial for functional scaffold design and clinical evaluation. Experimental determination, however, has been difficult due to the small length scale of the insertion sites. This study utilizes ultrasound elastography to characterize the response of the ACL and ACL–bone interface under tension. Specifically, bovine tibiofemoral joints were mounted on a material testing system and loaded in tension while radiofrequency (RF) data were acquired at 5 MHz. Axial strain elastograms between RF frames and a reference frame were generated using crosscorrelation and recorrelation techniques. Elastographic analyses revealed that when the joint was loaded in tension, complex strains with both compressive and tensile components occurred at the tibial insertion, with higher strains found at the insertion sites. In addition, the displacement was greatest at the ACL proper and decreased in value gradually from ligament to bone, likely a reflection of the matrix organization at the ligament–bone interface. Our results indicate that elastography is a novel method that can be readily used to characterize the mechanical properties of the ACL and its insertions into bone. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:2001–2010, 2006
Surface engineering of microchannel walls for protein separation and directed microfluidic flow
Authors: Huang Tom T. , Mosier Nathan S. , Ladisch Michael R.
Published: August 2006

The preparation of surfaces in microfluidic devices that selectively retain proteins may be difficult to implement due to the incompatibility of derivatization methods with microdevice fabrication techniques. This review describes recently reported developments in simple and rapid methods for engineering the surface chemistries of microchannels based on construction of press‐fit microdevices. These devices are fabricated by placing a glass fiber on a PDMS film and pressing the film on a silicon wafer or a microscope slide that has been derivatized with octadecyltrichlorosilane (ODS). The film adheres to the slide and forms an elliptically shaped channel around the fiber. The combination of surface wettability of a hydrophilic glass microfiber and the surrounding hydrophobic microchannel surfaces directs a narrow boundary layer of liquid next to the fiber in order to bring the sample in contact with the separation media and results in selective retention of proteins. This phenomenon may be exploited to enable microscale separation applications since there are a wide variety of fibers available with different chemistries. These may be used to rapidly fabricate microchannels that serve as stationary phases for separation at a microscale. The fundamental properties of such devices are discussed.
Learning to reduce degradation on Swaziland's arable land: enhancing understandings of Striga asiatica
Authors: Stringer L. C. , Twyman C. , Thomas D. S. G.
Published: August 2006

Maize production in Swaziland's middleveld is being increasingly threatened by the Striga asiatica weed (also called witchweed). It parasitises the maize crop to provide itself with water and nutrients, preventing the crop from growing properly. In this paper we examine the impacts of this bio‐indicator of land degradation on rural livelihoods, investigating how farmers and policy makers are responding to the problem. Our results show that farmers' ability to control weed infestations is determined by a number of environmental, social and political‐economic drivers and that national policies to reduce land degradation offer little assistance. Low‐technology methods employed by farmers are an important step in alleviating the problem, but farmers' understandings of why these methods work are limited and they often neglect to combine control strategies. At the local level, there is a need to support farmer‐to‐farmer learning and education programmes to broaden and deepen farmer knowledge about S. asiatica. At the national level a more supportive policy context is necessary that recognises weeds as an indicator of a more serious overall land degradation problem, and which uses broader criteria to determine what constitutes land degradation. Without this attention, the threat from S. asiatica could increase in both area and intensity, with profound effects on both food security and the sustainability of rural livelihoods. Copyright © 2006 John Wiley & Sons, Ltd.
Direct Measurement of Cure‐Induced Stress in Thermosetting Materials by Means of a Dynamic Mechanical Analyzer
Authors: Yu Hong , Mhaisalkar Subodh G. , Wong Ee Hua
Published: August 2006

Summary: Significant stresses develop during cure in functional and structural applications of polymeric materials ranging from glass fiber composites to advanced functional polymers used in microelectronics, optoelectronics, and biomaterials applications. These stresses arise from a combination of chemical shrinkage and stiffness buildup in a confined geometry. In this paper, a new method for direct measurement of cure‐induced stresses during curing of thermosetting materials by using the iso‐strain mode of a dynamic mechanical analyzer (DMA) has been developed. A thermal tape was used to facilitate maintaining a constant strain and initiate the iso‐strain measurement. Two quartz rods with a small gap were used to contain the material. The top of the quartz rod and one side of the thermal tape were secured by the fixed clamp, while the bottom quartz rod and the other side of the thermal tape were clamped with the moveable force probe. The cure force was thereby directly measured by the probe during the curing process. The cure stress buildup was observed to occur after a certain duration that corresponds to the gel point. Experimental results clearly show that curing at lower temperature could lead to higher cure stress due to the earlier onset of vitrification. An investigation of the stress buildup as a function of degree of cure indicates that a majority of the cure stress was generated in the vitrification regime. The methodology proposed herein provides an accurate experimental approach to investigate the cure‐induced stress generated in a thermosetting material in applications ranging from microelectronics and optoelectronics packaging to biomaterials amongst others.

Evolution of cure force and heat flow measured by means of DMA and DSC, respectively, at cure temperature 100 °C.

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Evolution of cure force and heat flow measured by means of DMA and DSC, respectively, at cure temperature 100 °C.
Protein gene product 9.5 is a spermatogonia‐specific marker in the pig testis: Application to enrichment and culture of porcine spermatogonia
Authors: Luo Jinping , Megee Susan , Rathi Rahul , Dobrinski Ina
Published: August 2006

Identification and isolation of spermatogonial stem cells (SSCs) are a prerequisite for culture, genetic manipulation, and/or transplantation research. In this study, we established that expression of PGP 9.5 is a spermatogonia‐specific marker in porcine testes. The expression pattern of PGP 9.5 in spermatogonia was compared to cell type‐specific protein (GATA‐4 or PLZF) expression in seminiferous tubules at different ages, and expression levels of PGP 9.5, Vasa, and Oct‐4 were compared in different cell fractions. Enrichment of spermatogonia from 2‐week‐old (2wo) and 10‐week‐old (10wo) boars by adhesion to laminin, differential plating, or velocity sedimentation followed by differential plating was assessed by identification of spermatogonia using expression of PGP 9.5 as a marker. Compared to the initial samples, spermatogonia were enriched twofold in laminin‐selected cells (P < 0.05), and fivefold either in cells remaining in suspension (fraction I) or in cells slightly attached to the culture dish (fraction II) (P < 0.05) after differential plating. Cells in fraction II appeared to be superior for future experiments due to higher viability (>90%) than in fraction I (∼50%). Velocity sedimentation plus differential plating achieved cell populations containing up to 70% spermatogonia with good viability (>80%). Enriched spermatogonia from 2wo and 10wo testes could be maintained in a simple culture medium without additional growth factors for at least 2 weeks and continued to express PGP 9.5. These data provide the basis for future studies aimed at refining conditions of germ cell culture and manipulation prior to germ cell transplantation in pigs. Mol. Reprod. Dev. 73: 1531–1540, 2006. © 2006 Wiley‐Liss, Inc.
Developmental potential of aged oocyte rescued by nuclear transfer following parthenogenetic activation and in vitro fertilization
Authors: Bai Zhao‐Dai , Liu Kai , Wang Xiao‐Yin
Published: August 2006

Mouse oocyte aged in vitro cannot develop normally following activation. To investigate the roles of nucleus or cytoplasm elements in oocyte aged in vitro process and their subsequent development capability following activation, we reconstructed oocytes with MII chromosome spindle and cytoplasm from aged and fresh oocytes by nuclear transfer. The subsequent developmental potential after parthenogenetic activation (PA) or in vitro fertilization (IVF) was evaluated. After nuclear transfer, more than 75.6% of karyoplast and cytoplast pairs can be fused and reconstructed oocytes have a normal haploid karyotype. Following PA, aged oocytes cannot develop beyond four‐cell stage, reconstructed oocytes from fresh nucleus and aged cytoplasm developed to blastocyst with a low percentage (9.1%). Instead, blastocyst formation rate of reconstructed oocyte from aged nucleus and fresh cytoplasm was higher (60.0%). Following IVF, zygote with diploid karyotype can be formed from zona pellucida (ZP)‐free oocyte. After cultured in vitro, aged oocytes cannot develop beyond two‐cell; reconstructed oocytes from fresh nucleus and aged cytoplasm developed to blastocyst with low percentage (15.0%). However, high blastocyst formation rate (86.2%) can be obtained from reconstructed oocytes from aged nucleus and fresh cytoplasm. Furthermore, after embryo transfer, three viable pups have been obtained, although the efficiency is very low. These observation demonstrated that cytoplasm is more crucial than nucleus to aging process. Fresh cytoplasm could partly rescue nucleus susceptibility to apoptosis from aging in vitro. Mol. Reprod. Dev. 73: 1448–1453, 2006. © 2006 Wiley‐Liss, Inc.
Expression of stress inducible protein 1 (Stip1) in the mouse testis
Authors: Mizrak S.C. , Bogerd J. , Lopez‐Casas P.P. , Párraga M. , del Mazo J. , de Rooij D.G.
Published: August 2006

Phthalate esters are considered endocrine disruptors that interfere with the endocrine balance and development of the mammalian testis. Mono‐2‐ethylhexyl phthalate (MEHP), the active metabolite of the ubiquitously used plasticizer di‐2‐ethylhexyl phthalate (DEHP), acts upon Sertoli cells as initial target. By subtractive cDNA libraries we identified genes deregulated as response to MEHP in primary cultures of mouse Sertoli cells. The expression of mouse stress inducible protein 1 (Stip1) was detected as upregulated as a result of MEHP exposure. Stip1 is a cochaperone protein that is homologous to the human heat shock cognate protein 70 (hsc70)/heat shock protein 90 (hsp90)—organizing protein (Hop). To assess the presence and localization of Stip1 in mouse testis and its potential role in stress defense, we studied the expression pattern of the Stip1 protein by immunohistochemistry and of the mRNA by in situ hybridization. Both the protein and the mRNA of Stip1 were mainly found in the cytoplasm of all types of spermatogonia and spermatocytes up till zygotene, the expression decreased during late pachytene and was very weak in diplotene spermatocytes and round spermatids. Interestingly, this expression pattern resembled the pattern of stress sensitivity of spermatogenic cells in that the most sensitive cell types show the weakest expression of Stip1. This suggests an important role for Stip1 in the ability of germ cells to survive in stress conditions including high temperatures. Mol. Reprod. Dev. 73: 1361–1366, 2006. © 2006 Wiley‐Liss, Inc.
Effects of cryopreservation on the developmental competence, ultrastructure and cytoskeletal structure of porcine oocytes
Authors: Wu Caihong , Rui Rong , Dai Jianjun , Zhang Chunyan , Ju Shiqiang , Xie Bing , Lu Xiao , Zheng Xiaofeng
Published: August 2006

The purpose of this study was to determine ultrastructural and cytoskeletal changes that result from vitrification of porcine germinal vesicle‐ (GV‐) and meiosis II‐ (MII‐) stage oocytes. To investigate the effects of vitrification on developmental competence, oocytes were divided into three groups: fresh GV‐oocytes (control), vitrified GV‐oocytes, and vitrified MII‐oocytes. In both GV‐ and MII‐oocytes, vitrification resulted in a high proportion with normal morphology (92.4 vs. 94.2%, P > 0.05), while vitrified GV‐oocytes yielded a higher survival rate than did vitrified MII‐oocytes (56.8 vs. 41.9%, P < 0.05). In vitrified GV‐oocytes, 12 of 154 oocytes underwent cleavage after fertilization in vitro, and 6 of these developed to the 8‐cell stage, 3 developed to the 16‐cell stage, and 3 developed into morulae. No cleavage was obtained from vitrified MII‐oocytes. For ultrastructural analysis of oocytes, fresh and vitrified‐warmed GV‐ and MII‐oocytes were randomly selected for transmission electron microscopy (TEM). Results showed that vitrification caused various degrees of cryodamage in GV‐oocytes. Cumulus cells of some oocytes were separated from the cumulus‐oocyte complex (COC), and the zona pellucida adjacent to cumulus cells was fractured. The gap junctions between cumulus cells were ruptured, and many microvilli were disrupted or disappeared. Only homogeneous lipid droplets were observed. After vitrification, cortical granules still lined the oolemma of MII‐oocytes. Only morphologically irregular, nonhomogeneous lipid droplets surrounding large vacuoles were found. To examine cytoskeletal structures, fresh and vitrified‐warmed MII‐oocytes were analyzed by laser‐scanning confocal microscopy (LSCM); vitrified‐warmed GV‐oocytes were cultured for 42–44 hr before LSCM. Of 58 control oocytes, 79.5% displayed normal spindles with chromosomes aligned along the equatorial plate. In vitrified oocytes the percentage with normal spindle organization was decreased significantly in both vitrified GV‐oocytes and MII‐oocytes (10.1 and 12.9%, respectively, P < 0.05). The proportion of oocytes with normal distribution of F‐actin was lower for vitrified GV‐ and MII‐oocytes than for controls (16.9 and 37.2% vs. 72.3%). Results of this experiment suggest that irreversible damage to the cytoskeleton of porcine GV‐ and MII‐oocytes after vitrification could be an important factor affecting developmental competence. Mol. Reprod. Dev. 73: 1454–1462, 2006. © 2006 Wiley‐Liss, Inc.
The histamine H1 receptor activates the nitric oxide pathway at fertilization
Authors: Leguia Mariana , Wessel Gary M.
Published: August 2006

Sperm fusion with the egg initiates a signaling cascade that releases intracellular calcium (Ca) from the endoplasmic reticulum (ER). In sea urchins, Ca2+ is released as a single, large transient via two distinct pathways. The first depends on inositol 1,4,5‐triphosphate (IP3) production and triggers the initial phase of Ca2+ release, while the second depends on nitric oxide (NO) production and is thought to maintain the duration of the Ca2+ wave. We identified a sea urchin homolog of the seven trans‐membrane G protein‐coupled receptor for histamine (suH1R) on the egg cell surface that activates NO production. Treatment with histamine (HA) causes fluctuations in the resting levels of NO in the egg, while antagonists or antibodies of H1R inhibit the rise of NO normally observed at fertilization. Inhibition of suH1R function decreases the maintenance, but not the amplitude, of the Ca2+ transient and suggests that it is an integral part of the overall pathway leading to egg activation at fertilization in sea urchins. Mol. Reprod. Dev. 73: 1550–1563, 2006. © 2006 Wiley‐Liss, Inc.