bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of the insulin-like growth factor axis and Wilms' tumour suppressor gene in hyperparathyroidism
Authors: Wong C K M , Lai T , White S , Sheffield E , Wheeler M H , Stewart C E H , Farndon J R
Published: July 2007

Background

Genetic mutations and upregulation of growth factors are implicated in the pathogenesis of hyperparathyroidism. The aim of this study was to evaluate the role of Wilms' tumour suppressor gene (WT-1) and the insulin-like growth factor (IGF) axis in hyperparathyroidism.

Methods

The expression of WT-1 and IGF components was examined by immunohistochemistry, reverse transcriptase–polymerase chain reaction and western immunoblotting in a panel of parathyroid specimens from both primary and secondary hyperparathyroidism. A human parathyroid cell culture model was established to examine the parathyroid response to IGF stimulation.

Results

There was a significantly lower level of WT-1 expression in parathyroid tumours than in normal parathyroid glands. Most tumours expressed IGF-I and IGF-II receptors and responded to IGF stimulation. Only IGF-I was present in normal parathyroid glands, whereas IGF-II was expressed exclusively in parathyroid tumours.

Conclusion

Abnormal expression of WT-1 and the IGF axis may play a role in the pathogenesis of hyperparathyroidism.
Selecting patients with young-onset colorectal cancer for mismatch repair gene analysis
Authors: Walker M , O'Sullivan B , Perakath B , Taniere P , Cruger D , Morton D
Published: July 2007

Background

Young patients with colorectal cancer are at increased risk of carrying a germline mutation in mismatch repair (MMR) genes. This study investigated the role of clinical criteria and immunohistochemistry for MMR proteins in selecting young patients for mutation testing.

Methods

A cohort of 56 consecutive patients with colorectal cancer aged less than 45 years were stratified into three groups based on clinical criteria: ‘Amsterdam criteria’, ‘high risk’ and ‘young onset only’. Immunohistochemistry for four MMR proteins was carried out and the rate of compliance with clinical guidelines determined.

Results

Tumours from 11 patients (20 per cent) had abnormal MMR protein expression, of whom eight were referred for genetic assessment. Of 21 patients (38 per cent) in total referred to the genetics unit, six MMR gene mutations were identified, all associated with abnormal immunohistochemistry.

Conclusion

MMR immunohistochemistry should be considered routine in young-onset colorectal cancer.
Prospective randomized study of the restenotic process in small coronary arteries using a Carbofilm™ coated stent in comparison with plain old balloon angioplasty:
Authors: Braun Peter
Published: August 2007

Background: The optimal interventional approach to treat lesions in small coronary arteries is still undetermined and controversial. This randomized, multicenter trial was designed to compare the 6‐months restenosis and clinical event rates in two treatment groups: balloon angioplasty as a primary strategy and provisional stenting versus primary implantation of a carbon coated stent (Carbosten™). Results: At 6 months the angiographic restenosis rate was significantly lower for the stented patients (11.6%) as compared to the balloon angioplasty patients (32.2%). However this advantage in restenosis rate did not translate into a clinical benefit in respect to target vessel revascularization rates. Conclusion: This trial demonstrated a remarkably low 6‐months restenosis rate for lesions in small (<2.8 mm) coronary arteries treated with Carbostent™ implantation that is comparable to the rates found after drug eluting stent implantation and was significantly better in comparison to balloon angioplasty alone. © 2007 Wiley‐Liss, Inc.
Generalized FEAR method to estimate factor effects in two‐level supersaturated designs
Authors: Dejaegher B. , Capron X. , Vander Heyden Y.
Published: July 2007

Two‐level supersaturated (SS) designs examine more than NSS − 1 factors in NSS experiments. A proper estimation of the factor effects is not evident due to a confounding of the main effects. In this paper, a generalization of the earlier proposed Fixing Effects and Adding Rows (FEAR) method, to estimate effects from SS designs, is presented. Three data sets, examining SS designs (NSS = 12 or 14), were used to evaluate the FEAR method further. The factor and critical effects estimated from SS designs with the FEAR method are usually similar to those estimated classically from N = 24 or N = 28 screening designs, examining the same factors, when the effect sparsity principle largely is fulfilled, that is very few significant effects occur. It was found that in those cases the FEAR method can correctly indicate the important significant effects. This is not the case anymore when the number of significant effects is too high. However, classically applied methods also fail in these situations. It also was observed that different (NSS experiments, fSS > NSS − 1 factors) SS designs, which have a different confounding pattern, either can result in good or worse effect estimates. Copyright © 2007 John Wiley & Sons, Ltd.
Selective Inclusion of Electron‐Donating Molecules into Porphyrin Nanochannels Derived from the Self‐Assembly of Saddle‐Distorted, Protonated Porphyrins and Photoinduced Electron Transfer from Guest Molecules to Porphyrin Dications
Authors: Kojima Takahiko , Nakanishi Tatsuaki , Harada Ryosuke , Ohkubo Kei , Yamauchi Seigo , Fukuzumi Shunichi
Published: July 2007

A doubly protonated hydrochloride salt of a saddle‐distorted dodecaphenylporphyrin (H2DPP), [H4DPPP]Cl2, forms a porphyrin nanochannel (PNC). X‐ray crystallography was used to determine the structure of the molecule, which revealed the inclusion of guest molecules within the PNC. Electron‐donating molecules, such as p‐hydroquinone and p‐xylene, were selectively included within the PNC in sharp contrast to electron acceptors, such as the corresponding quinones, which were not encapsulated. This result indicates that the PNC can recognize the electronic character and steric hindrance of the guest molecules during the course of inclusion. ESR measurements (photoirradiation at λ>340 nm at room temperature) of the PNC that contains p‐hydroquinone, catechol, and tetrafluorohydroquinone guest molecules gave well‐resolved signals, which were assigned to cation radicals formed without deprotonation based on results from computer simulations of the ESR spectra and density functional theory (DFT) calculations. The radicals are derived from photoinduced electron transfer from the guest molecules to the singlet state of H4DPP2+. Transient absorption spectroscopy by femtosecond laser flash photolysis allowed us to observe the formation of 1(H4DPP2+)*, which is converted to H4DPP+. by electron transfer from the guest molecules to 1(H4DPP2+)*, followed by fast disproportionation of H4DPP+., and charge recombination to give diamagnetic species and the triplet excited state 3(H4DPP2+)*, respectively.
Encapsulation of Small Polar Guests in Molecular Apple Peels
Authors: Garric Joachim , Léger Jean‐Michel , Huc Ivan
Published: July 2007

Three aromatic oligoamides have been prepared that have alternating 1,6‐diaminopyridine and 1,6‐pyridinedicarboxylic acid units at the center of the sequence and two 8‐amino‐2‐quinolinecarboxylic acid units at each extremity. The three oligomers differ in the number–‐3, 5, or 7—of pyridine units in the sequence. They were designed to adopt helically folded conformations in solution and in the solid state. The sequence of monomers was chosen so that the diameter of the helix is larger in the center than at each extremity, and hence they resemble helically wrapped apple peels. According to modeling studies, the pyridine units were expected to define a polar hollow within the helix that is large enough to accommodate small polar guests, whereas the quinoline units at each end of the oligomeric sequences were expected to completely cap the hollow and transform the helix cavities into a closed shell that may act as a capsule. Crystallographic studies demonstrate that the oligomers do fold into helices that define a cavity isolated from the surrounding medium in the solid state. Depending on the number of pyridine rings, one or two water molecules are bound within the capsules. The crystal structure of a capsule fragment shows that MeOH can also be hosted by the largest oligomer. Solution NMR studies confirm that binding of water also occurs in solution with the same stoichiometry as observed in the solid state. The capsules have distinct signals depending on whether they are empty, half‐full, or full, and these species are in slow exchange on the NMR timescale at low temperature. Indeed, the binding and release of water molecules requires a significant conformational distortion of the helix that slows down these processes. The addition of small polar molecules such as methanol, hydrazine, hydrogen peroxide, or formic acid to the largest capsule leads to the observation of new sets of NMR signals of the capsules that were assigned to complexes with these guests. However, water appears to be the preferred guest.
Technische Anwendung von Enzymen: Weiße Wäsche und Grüne Chemie
Authors: Osterath Brigitte , Rao Nagaraj , Lütz Stephan , Liese Andreas
Published: July 2007

In den Laboren von Mutter Natur sind die effizientesten und spezifischsten Katalysatoren überhaupt entstanden: Enzyme. Die Menschheit benutzt diese Proteine schon seit Jahrtausenden, zum Beispiel für die Käseherstellung. Inzwischen haben Enzyme sich einen riesigen Markt in Industrie und Handwerk erobert und weitere Expansionen sind sicher. Anwendungen reichen von Waschmittel und Textilien über Lebensmittel bis hin zu Tierfutter und Medikamenten. Stone‐washed Jeans, Antibiotika, verbesserte Weinkorken und Eiscreme – all diese Produkte ermöglichen uns ein ziemlich enzymerfülltes Leben!
Die Chemie der schillernden Scheiben: CD, DVD & Co.
Authors: Roth Klaus
Published: July 2007

Die Compact Disc (CD) und ihre Abkömmlinge haben in wenigen Jahren die Speicherung von Musik und anderen digitalen Daten revolutioniert. Aus chemischer Sicht sind sie wahre Hightech‐Produkte, angefangen beim Trägermaterial Polycarbonat bis zum kratzfesten Schutzlack. Zweifellos sind heute (noch) die einmal beschreibbaren CD/Rs und DVD/Rs das beliebteste Medium zum Speichern und Verbreiten digitaler Informationen. Sie sind das außergewöhnliche Ergebnis der modernen Farbenchemie. Trotz des bemerkenswerten Fortschritts der optischen Datenspeicherung lehrt uns die Chemie auch, dass nicht jeder alles für immer speichern kann. Verbesserte Nachfolger der CD und DVD schauen bereits um die Ecke, aber wie auch immer das digitale Speichermedium von morgen aussehen wird, eins ist klar: Es wird nicht perfekt sein, es wird nicht ewig halten, aber der Speicherplatz für ein einziges bit wird kleiner und preiswerter werden und jede Menge Chemie wird darin stecken. Da können Sie ganz sicher sein!
Atmosphärenchemie des Saturnmonds Titan
Authors: Groß Michael
Published: July 2007

Als die Raumsonden Voyager I und II in den Jahren 1981–82 das Saturnsystem durchquerten, lieferten sie beeindruckende Fotos nicht nur von dem Ringplaneten selbst, sondern auch von seinen zahlreichen Trabanten. Einer der Monde blieb allerdings den scharfen Augen der Sonden verborgen, da er dauerhaft in einen dicken Nebel aus orangefarbenen Chemikalien eingehüllt zu sein schien: Titan.
Die Wassersucher
Authors: Harrer Roswitha
Published: July 2007

Gibt oder gab es flüssiges Wasser auf dem Mars? Die Geschichte der Erforschung des Mars ist, vor allem in neuerer Zeit, die Geschichte einer Wassersuche. Flüssiges Wasser gilt als Voraussetzung zur Entstehung von Leben. Tatsächlich gibt es bereits eine Fülle von Hinweisen dafür, dass der Mars einst ein feuchter Planet gewesen ist.
Is full bilateral retroperitoneal lymph node dissection always necessary for postchemotherapy residual tumor?
Authors: Beck Stephen D. W. , Foster Richard S. , Bihrle Richard , Donohue John P. , Einhorn Lawrence H.
Published: July 2007

BACKGROUND.

Traditionally, postchemotherapy (PC) surgery for metastatic nonseminomatous germ cell tumor (NSGCT) has used a full bilateral retroperitoneal lymph node dissection (RPLND) from the crus of the diaphragm to the bifurcation of the common iliac arteries, from ureter to ureter. With the primary landing zone well defined in low‐volume retroperitoneal disease, the authors performed modified dissections in the PC setting in a select population; and, herein, they report disease outcome.

METHODS.

From 1991 to 2004, a retrospective review of the testicular cancer database at the authors' institution was performed to identify patients with NSGCT, normal serum tumor markers after cisplatin‐based chemotherapy, and residual retroperitoneal tumor who underwent modified PC‐RPLND. All patients had metastatic disease at initial presentation that was limited to the primary landing zone (left or right).

RESULTS.

One hundred patients were identified, including 43 who underwent a right modified template, 18 patients who underwent a left full modified template, and 39 patients who underwent a left modified template. Pathology revealed cancer in 2% of patients, teratoma in 62% of patients, and necrosis in 36% of patients. The 2‐ and 5‐year disease‐free survival rate was 95%, and the median follow‐up was 31.9 months (range, 1–152 months). Four patients developed recurrent disease with a median time to recurrence of 8.25 months (range, 6–11 months). All recurrences were outside the boundaries of a full bilateral RPLND.

CONCLUSIONS.

Selected patients at PC surgery can be managed with modified PC‐RPLND. Cancer 2007. © 2007 American Cancer Society.
Thyroid carcinomas with a variable insular component
Authors: Rufini Vittoria , Salvatori Massimo , Fadda Guido , Pinnarelli Luigi , Castaldi Paola , Maussier Maria Lodovica , Galli Guido
Published: July 2007

BACKGROUND.

An insular growth pattern may be observed focally both in papillary and follicular thyroid carcinoma. The aim of the current study was to determine whether a greater extension of the insular component (IC) influences different clinical and histologic features at diagnosis, and a different tumor aggressiveness in terms of frequency in the occurrence of metastases as well as survival.

METHODS.

Thirty‐three patients with histopathologic findings consistent with IC were included in the study. IC was focal (<50% of the tumor area) in 16 patients and predominant (>50% of the tumor area) in 17 patients. These 2 groups were compared with a control group of 66 patients with differentiated thyroid carcinoma.

RESULTS.

At diagnosis, carcinomas with predominant IC differed from those with focal IC with regard to greater tumor size and a higher frequency of extrathyroidal extension and distant metastases. Patient follow‐up ranged from 5 to 188 months. The cumulative rate of distant metastases was significantly higher in patients with predominant IC. At the time of last follow‐up, carcinomas with predominant IC demonstrated a lesser frequency of disease‐free outcome (P = .002) and a higher number of tumor‐related deaths (P = .002), either when distant metastases were present (P = .03) or absent (P = .05) at the time of diagnosis.

CONCLUSIONS.

The presence of predominant IC is associated with a poor prognosis in terms of ongoing disease or death. Predominant IC should be considered a separate entity from not only the classical papillary or follicular carcinomas but also the focal IC tumor. Cancer 2007. © 2007 American Cancer Society.
Neuronal and glial cell changes are determined by retinal vascularization in retinopathy of prematurity
Authors: Downie Laura E. , Pianta Michael J. , Vingrys Algis J. , Wilkinson‐Berka Jennifer L. , Fletcher Erica L.
Published: July 2007

We have characterized the vascular, neuronal, and glial changes in oxygen‐induced retinopathy, a model of retinopathy of prematurity (ROP). Newborn Sprague‐Dawley rats were exposed to either 80% ± 2% oxygen to postnatal day P11 and then room air until P18 (ROP) or room air for the entire duration (controls). Retinal structure was examined under the light microscope and following postembedding immunocytochemistry in central, midperipheral, and peripheral regions. Müller cells were evaluated immunocytochemically with glial fibrillary acidic protein. The extent of vascularization was established histologically. ROP caused significant thinning of the inner cellular and plexiform layers, which became more pronounced in the peripheral inner nuclear layer of ROP animals (11.3% loss vs. 25.4% loss). Amacrine cell amino acid levels were particularly vulnerable in the peripheral retina; bipolar cells showed similar but less prominent changes. Müller cells had elevated glutamine levels and were most gliotic in the periphery. The vasculature extended to peripheral retinal regions at P18 in controls but not in ROP rats. The most striking pattern of change was evident in the midperipheral “transition zone” of ROP animals. Areas close to blood vessels showed neurochemical properties that were similar to those of the central retina, indicating a local protective effect of the inner retinal blood supply. We find that ROP produces complex vascular, neural, and glial changes that relate to the proximity of inner retinal blood vessels. J. Comp. Neurol. 504:404–417, 2007. © 2007 Wiley‐Liss, Inc.
On the evaluation of flooding‐based search strategies in peer‐to‐peer networks
Authors: Gaeta Rossano , Sereno Matteo
Published: July 2007

This paper develops a directed generalized random graphs based analytical modeling framework to compare several variations of the basic flooding search strategy in unstructured decentralized peer‐to‐peer networks. To validate the model predictions, we designed and implemented a distributed crawler architecture that is able to efficiently capture snapshots of the top‐level Gnutella overlay topology. The snapshots are used to obtain simulation results that are used to assess the accuracy of our model. The model predictions are then used to compute system‐oriented performance indexes (the average and the coefficient of variation of the number of query messages) as well as user‐oriented measures (the probability of finding at least one replica of a resource, the average search time). The trade‐off between the optimization of system‐oriented measures and the improvement of user‐oriented quality indexes is investigated for several variations of the basic flooding strategy suggesting that adding control parameters to the basic flooding mechanism might prove beneficial in this class of systems. Copyright © 2007 John Wiley & Sons, Ltd.
Metabolic Products of the Endophytic Fungus Microsphaeropsis sp. from Larix decidua
Authors: Dai Jingqiu , Krohn Karsten , Elsässer Brigitta , Flörke Ulrich , Draeger Siegfried , Schulz Barbara , Pescitelli Gennaro , Salvadori Piero , Antus Sándor , Kurtán Tibor
Published: July 2007

Five new metabolites, palmarumycin M1 (1a) and M2 (3), papyracillic acid C (6) and the microsphaeropsins A (7) and B (8) were isolated from the fungus Microsphaeropsis sp. together with the known decaspirone (2) and the papyracillic acids A and B (4 and 5). Their structures were determined by means of spectroscopic data including HREIMS, 1H NMR, 13C NMR, 2D NMR (HMQC, HMBC, NOESY) and X‐ray single crystal analysis. The absolute configuration of palmarumycin M1 (1a) was determined by single‐crystal X‐ray analysis of the bis(4‐bromobenzoate) 1c and the relationship between 1a, 2 and 3 established by chemical transformation of 1a into 2 and of 3 into 2. The relative configuration of papyracillic acids A–C (4–6) was revised and their absolute configuration determined by comparison of TDDFT‐calculated and experimental solid‐state CD spectra.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
A New Approach to the Synthesis of N,N‐Dialkyladenine Derivatives
Authors: Alves M. José , Carvalho M. Alice , Carvalho Sílvia , Dias Alice M. , Fernandes Francisco H. , Proença M. Fernanda
Published: July 2007

N,N‐Dialkyladenine derivatives were prepared by two different reaction sequences starting from 5‐amino‐4‐cyanoformimidoylimidazoles. When these imidazoles were treated with dimethylformamide diethyl acetal, a 5‐aminomethyleneamino‐4‐cyanoformimidoylimidazole was isolated and evolved to the N,N‐dialkyladenine in the presence of a secondary alkylamine. The same purine structure was isolated when the 5‐amino‐4‐cyanoformimidoylimidazole was first treated with a secondary amine to give a stable 4‐amidino‐5‐aminoimidazole. The desired product was generated when the 4‐amidino‐5‐aminoimidazole was combined with dimethylformamide diethyl acetal, at room temperature. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis of Substituted 2,3‐Dihydro‐1H‐2‐benzazepines and 1,2‐Dihydroisoquinolines Using an Isomerization‐Ring‐Closing Metathesis Strategy: Scope and Limitations
Authors: Panayides Jenny‐Lee , Pathak Rakhi , de Koning Charles B. , van Otterlo Willem A. L.
Published: July 2007

An isomerization‐ring‐closing metathesis (RCM) approach was used for the synthesis of substituted 2,3‐dihydro‐1H‐2‐benzazepines and 1,2‐dihydroisoquinolines. The 2,3‐dihydro‐1H‐2‐benzazepines were obtained from N‐protected N‐{2‐[(1E)‐prop‐1‐en‐1‐yl]benzyl}prop‐2‐en‐1‐amines by RCM reaction. A double isomerisation reaction on the N‐protected N‐(2‐allylbenzyl)prop‐2‐en‐1‐amines and a subsequent RCM afforded the substituted 1,2‐dihydroisoquinolines. Finally, a selective isomerization of the allylamine group of N‐protected N‐(2‐allylbenzyl)prop‐2‐en‐1‐amines by [RuClH(CO)(PPh3)3], followed by RCM, did not afford the expected 2,5‐dihydro‐1H‐2‐benzazepines but afforded products resulting from deallylation and isomerization of the starting material.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
BiCl3‐Catalyzed Hydroamination of Norbornene with Aromatic Amines
Authors: Wei Hua , Qian Guimin , Xia Yuanzhi , Li Kai , Li Yahong , Li Wu
Published: July 2007

A BiCl3‐catalyzed hydroamination reaction of norbornene, in which a variety of electron‐withdrawing groups were tolerated on amines, was presented. The current transformation possesses the advantages of being highly selective, cheap, and eco‐friendly, and this process also represents a rare system for main‐group Lewis acid catalyzed intermolecular hydroamination of unactivated alkenes.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Thermally Induced [2+2] Cycloadditions of (Benzyloxymethylene)cyclopropane with Alkylidenemalononitriles
Authors: Nakamura Itaru , Nagata Ryoko , Nemoto Tetsuya , Terada Masahiro , Yamamoto Yoshinori , Späth Thomas , de Meijere Armin
Published: July 2007

The reaction of (benzyloxymethylene)cyclopropane (1a) with alkylidenemalononitriles 2 at ambient pressure afforded the corresponding cyclobutane derivatives 3 in good‐to‐high yields. For example, the reaction of 1a with benzylidenemalononitrile (2a), (2‐naphthylmethylene)malononitrile (2e), and tert‐butylmethylenemalononitrile (2f) in acetonitrile at 80 °C gave the corresponding cyclobutanes 3a, 3e, and 3f in 96, 96, and 91 % yield, respectively. Control experiments proved that the reaction proceeds via well‐stabilized zwitterionic intermediate 6. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Silica nanoparticles as pseudostationary phase for protein separation
Authors: Qin Weidong
Published: July 2007

This paper investigated the potential use of silica nanoparticles (SNPs) as pseudostationary phase (PSP) for protein separation. The wall adsorption of SNPs as well as the influences of SNPs and poly(ethylene oxide) (PEO) were studied. The SNPs showed selectivity toward the proteins, and the concentration ratio of SNPs to PEO influenced the separation. The proteins that could not be baseline‐resolved under conventional CZE mode were separated in a buffer consisting of 30 mM phosphoric acid, 0.05% PEO, and 0.05% SNPs at pH 2.37, with detection limits ranging from 2 to 45.5 ppm. The intraday and interday RSDs of the migration times were in the ranges of 2.1–2.8% (n = 5) and 2.5–3.4% (three days, n = 3×5 = 15), respectively.
Effects of novel quasi‐interpenetrating network/gold nanoparticles composite matrices on DNA sequencing performances by CE
Authors: Zhou Dan , Wang Yanmei , Yang Runmiao , Zhang Wenlong , Shi Ronghua
Published: July 2007

Gold nanoparticles (GNPs) with particle sizes of about 20, 40, and 60 nm were prepared and added into a quasi‐interpenetrating network (quasi‐IPN) composed of linear polyacrylamide (LPA) with different viscosity‐average molecular masses of 1.5, 3.3, and 6.5 MDa and poly‐N,N‐dimethylacrylamide (PDMA) to form polymer/metal composite matrices, respectively. These novel matrices could improve ssDNA sequencing performances due to interactions between GNPs and polymer chains and the formation of physical cross‐linking points as demonstrated by intrinsic viscosities and glass transition temperatures. The effects of the parameters in relation to quasi‐IPN/GNPs matrices, such as GNP contents, GNP particle sizes, LPA molecular masses, and solution concentrations, on ssDNA sequencing performances were studied. In the presence of GNPs, the separation had the advantages of high resolution, speediness, excellent reproducibility, long shelf life and easy automation. Therefore, less viscous matrix solutions (with moderate size GNPs) due to lower solution concentration and lower‐molecular‐mass LPA could be used to replace more viscous solutions (without GNPs) due to higher solution concentration or higher‐molecular‐mass LPA to separate DNA, while the sieving performances were approximate even higher, which helped to achieve full automation especial for capillary array electrophoresis (CAE) and microchip electrophoresis (MCE).
Diffusion-weighted magnetic resonance imaging for the assessment of fibrosis in chronic hepatitis C
Authors: Lewin Maïté , Poujol-Robert Armelle , Boëlle Pierre-Yves , Wendum Dominique , Lasnier Elisabeth , Viallon Magalie , Guéchot Jérôme , Hoeffel Christine , Arrivé Lionel , Tubiana Jean-Michel , Poupon Raoul
Published: July 2007

Liver biopsy is the gold standard for assessing fibrosis but has several limitations. We evaluated a noninvasive method, so-called diffusion-weighted magnetic resonance imaging (DWMRI), which measures the apparent diffusion coefficient (ADC) of water, for the diagnosis of liver fibrosis in patients with chronic hepatitis C virus (HCV). We analyzed 20 healthy volunteers and 54 patients with chronic HCV (METAVIR: F0, n = 1; F1, n = 30; F2, n = 8; F3, n = 5; and F4, n = 10) prospectively included. Patients with moderate-to-severe fibrosis (F2-F3-F4) had hepatic ADC values lower than those without or with mild fibrosis (F0-F1; mean: 1.10 ± 0.11 versus 1.30 ± 0.12 × 10−3 mm2/s) and healthy volunteers (mean: 1.44 ± 0.02 × 10−3 mm2/s). In discriminating patients staged F3-F4, the areas under the receiving operating characteristic curves (AUCs) were 0.92 (±0.04) for magnetic resonance imaging (MRI), 0.92 (±0.05) for elastography, 0.79 (±0.08) for FibroTest, 0.87 (±0.06) for the aspartate aminotransferase to platelets ratio index (APRI), 0.86 (±0.06) for the Forns index, and 0.87 (±0.06) for hyaluronate. In these patients, the sensitivity, specificity, positive predictive value, and negative predictive value were 87%, 87%, 72%, and 94%, respectively, with an ADC cutoff level of 1.21 × 10−3 mm2/s. In discriminating patients staged F2-F3-F4, the AUC values were 0.79 (±0.07) for MRI, 0.87 (±0.05) for elastography, 0.68 (±0.09) for FibroTest, 0.81 (±0.06) for APRI, 0.72 (±0.08) for the Forns index, and 0.77 (±0.06) for hyaluronate.

Conclusion:

This preliminary study suggests that DWMRI compares favorably with other noninvasive tests for the presence of significant liver fibrosis. (Hepatology 2007.)
The role of lithology, catchment size and the alluvial zone on the hydrogeochemistry of two intermittent Mediterranean streams
Authors: Bernal Susana , Sabater Francesc
Published: July 2007

Hydrology and solute concentrations of two intermittent Mediterranean streams draining two nested catchments were compared. The two catchments were mainly underlain by granitic rocks and different types of sericitic schists. Only the lowland catchment had an alluvial zone and a well‐developed riparian forest. The rainfall–runoff relationship and the correlation between daily flow concentrations showed that hydrological behaviour was similar at both sites during most of the year. However, reverse fluxes were detected during the wetting and drying up periods only in the stream with an alluvial zone. The intermittence in stream flow also had effects on absolute solute concentrations, temporal solute dynamics and streamwater stoichiometry. Streamwater chemistry was not affected by drainage area, except for cations produced mainly by bedrock dissolution (i.e. calcium and magnesium) that increased with increasing catchment size. Differences in the relationship among cations and anions were detected between the two streams, which could be attributed to biogeochemical processes occurring in the alluvial zone. The multivariate model used in this study showed that stoichiometry was more useful than absolute concentrations when analyzing the influence of different lithologies on streamwater chemistry. Such differences were amplified in autumn, likely due to a low hydrological connectivity between the two nested catchments. Copyright © 2007 John Wiley & Sons, Ltd.
Physically‐based modelling of double‐peak discharge responses at Slapton Wood catchment
Authors: Birkinshaw Stephen J
Published: July 2007

Heavy winter rainfall produces double‐peak hydrographs at the Slapton Wood catchment, Devon, UK. The first peak is saturation‐excess overland flow in the hillslope hollows and the second (i.e. the delayed peak) is subsurface stormflow. The physically‐based spatially‐distributed model SHETRAN is used to try to improve the understanding of the processes that cause the double peaks. A three‐stage (multi‐scale) approach to calibration is used: (1) water balance validation for vertical one‐dimensional flow at arable, grassland and woodland plots; (2) two‐dimensional flow for cross‐sections cutting across the stream valley; and (3) three‐dimensional flow in the full catchment. The main data are for rainfall, stream discharge, evaporation, soil water potential and phreatic surface level. At each scale there was successful comparison with measured responses, using as far as possible parameter values from measurements. There was some calibration but all calibrated values at one scale were used at a larger scale.

A large proportion of the subsurface runoff enters the stream from three dry valleys (hillslope hollows), and previous studies have suggested convergence of the water in the three large hollows as being the major mechanism for the production of the delayed peaks. The SHETRAN modelling suggests that the hillslopes that drain directly into the stream are also involved in producing the delayed discharges. The model shows how in the summer most of the catchment is hydraulically disconnected from the stream. In the autumn the catchment eventually ‘wets up’ and shallow subsurface flows are produced, with water deflected laterally along the soil‐bedrock interface producing the delayed peak in the stream hydrograph. Copyright © 2007 John Wiley & Sons, Ltd.
Effects of fire‐induced water repellency on soil aggregate stability, splash erosion, and saturated hydraulic conductivity for different size fractions
Authors: Fox D. M. , Darboux F. , Carrega P.
Published: July 2007

Forest fires can alter several soil properties influencing soil erosion and runoff processes in addition to removing all or part of the vegetative cover. These include organic matter content, aggregate stability and water repellency. Soil erodibility and saturated hydraulic conductivity depend on these properties and their response varies according to aggregate size. The objective of the study was to investigate how forest fires affect key soil properties and determine the potential impact of these on runoff and erosion processes. The A horizon of an acidic sandy loam was collected and subjected to a pine litter fire. The burned and control soil samples were separated into 4 size fractions: bulk (<5·0 mm), < 0·4, 0·4–2·0, and 2·0–5·0 mm. Organic matter (OM), aggregate stability mean weight diameter (MWD), and water drop penetration time (WDPT) were measured for each size class. Each size fraction sample was subjected to 0·5 h of simulated rainfall (55 mm h−1) for splash erosion measurements. Saturated hydraulic conductivity (K) measurements were performed on the same samples. Burning the litter decreased soil OM content but increased MWD and WDPT. Splash erosion increased greatly for the bulk and < 0·4 mm samples. MWD increased for the 0·4–2·0 and 2·0–5·0 mm size fractions despite a loss in OM and clay content in the burned soil. A surface crust never formed on the water repellent fine fraction leaving plenty of non‐cohesive material available for soil detachment. Increased water repellency reduced K for all size fractions. The data support the need for a specific soil erodibility index for post‐forest fire soils. Copyright © 2007 John Wiley & Sons, Ltd.
The association between three dominant shrub species and water repellent soils along a range of soil moisture contents in semi‐arid Spain
Authors: Verheijen F. G. A. , Cammeraat L. H.
Published: July 2007

Soil water repellency (SWR) is a widespread phenomenon associated with decreased infiltration rates, fingered flow infiltration, and increased runoff. In Spain, research into the causes of SWR has focused on fire‐induced effects. This research investigates the impact of different plant species and soil moisture contents (SMCs) on the water repellency of the surface soil horizon in a semi‐arid shrubland ecosystem. The plant species were selected for their different wax input rates into the soil. In situ (field) SWR was investigated spatially, whereas in the laboratory it was assessed over a soil moisture range. The selected plant species were Stipa tenacissima, Anthyllis cytisoides and Rosmarinus officinalis.

In the field, water repellency was found to be limited strictly to an organic soil layer (‘mulch’) between the soil crust and the ectorganic profile (litter, fragmentation and humification layers). When comparing the three species, soil under Stipa was found to be wettable or slightly water repellent, soil under Anthyllis and Rosmarinus severely water repellent. The water repellency of the surface soil appeared to be related to the thickness of the ectorganic profile.

The soil organic carbon (SOC) contents correlated with water repellency (r2 = 0·74, p = 0·01). Water repellency displayed a two‐peak distribution over a soil moisture range. The first peak ranged from 22 to 26% SMC (w w−1), the second peak from 45 to 47%. The integrated area in a ‘WDPT versus SMC’ graph was calculated. Soil under Stipa, Anthyllis and Rosmarinus was water repellent in the ratios 1: 2·3: 4·5. The integrated area measurement had a better reproducibility and was more stable than SWR measurements at specific SMCs.

It is concluded that, in the investigated ecosystem, SWR occurs without the influence of fire but underneath individual plants (fertile islands) only; plant species affect SWR substantially differently; and SWR occurs over a wide range of SMCs. Appropriate measures of SWR are discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Preparation and characterization of novel fluorescent nanocomposite particles: CdSe/ZnS core‐shell quantum dots loaded solid lipid nanoparticles
Authors: Liu Wei , He Zhike , Liang Jiangong , Zhu Yaoliang , Xu Huibi , Yang Xiangliang
Published: August 2007

Fluorescent quantum dots (QDs, semiconductor nanocrystals) have gained increasing attention in the past decade due to their unique optical properties. In this work, we synthesized highly luminescent lipophilic CdSe/ZnS core‐shell QDs under mild conditions, and encapsulated the QDs into solid lipid nanoparticles (SLNs) to prepare fluorescent nanocomposite particles. The transmission electron microscopy image showed that the QDs were nearly monodispersed and uniform with an average diameter of about 4 nm. The fluorescence spectrum of the QDs was symmetric and narrow with an emission maximum at 556 nm. Characterized by photon correlation spectroscopy (PCS) and zeta potential measurement, the nanocomposite particles (QDs‐loaded SLNs) exhibit an average particle size of about 90 nm and zeta potential of about −28 mV. Fluorescence measurements showed that the encapsulated QDs maintain their high fluorescence and narrow/symmetric emission spectra. Assembling many QDs in single nanocomposite particle significantly increases the fluorescence signal and the signal‐to‐background ratio compared to individual QDs. In vitro and in vivo imaging indicated that QDs‐loaded SLNs were stable and slow to photobleach. These fluorescent QDs‐loaded SLNs were biocompatible with fluorescence stability and had good potential in biological imaging applications. The approaches could also be used to encapsulate other optical nanocrystals or magnetic nanoparticles, and allow them to be used under aqueous biological conditions. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Use of electrochemical impedance spectroscopy to evaluate resin‐dentin bonds
Authors: Sword Jeremy , Pashley David H. , Foulger Stephen , Tay Franklin R. , Rodgers Robert
Published: August 2007

Electrochemical impedance spectroscopy (EIS) offers a potentially nondestructive quantitative method for measuring the stability of resin films and or resin‐bonded dentin over time. The purpose of this study was to measure the electrical impedance of five experimental dental adhesives of increasing hydrophicities as 30‐μm films and as resin‐bonded coatings on acid‐etched dentin. Resin films or resin‐coated dentin disks were placed in U‐shaped chambers containing pairs of Ag–AgCl electrodes in 0.1M KCl. Electrical impedance spectra were run at day 0, 1, 7, 14, and 21 days. All resin films and resin‐bonded dentin showed increases in capacitance during the first day of storage in electrolyte. This was usually associated with an increase in the pore resistance of the resins. Generally, resin‐bonded dentin gave lower impedance values than their respective resins (resins 1–4) but solvated resin 5 bonded to water‐saturated dentin gave higher capacitance and impedance values than resin 5 films. However, solvated resin 5 films gave higher impedance values than resin 5‐bonded dentin. This behavior was confirmed by TEM examinations of silver uptake into films of neat resin 5 vs. ethanol‐solvated resin 5, where water tree‐like structures seen in the former were not seen in the latter. EIS is useful in examining changes in the capacitance and electrical impedance of very hydrophilic, ionic methacrylate resins. Its utility in detecting degradation in resin‐bonded dentin interfaces remains to be determined in longer term studies. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
An insight into the environmental effects of the pocket of the active site of the enzyme. Ab initio ONIOM‐molecular dynamics (MD) study on cytosine deaminase
Authors: Matsubara Toshiaki , Dupuis Michel , Aida Misako
Published: July 2007

We applied the ONIOM‐molecular dynamics (MD) method to cytosine deaminase to examine the environmental effects of the amino acid residues in the pocket of the active site on the substrate taking account of their thermal motion. The ab initio ONIOM‐MD simulations show that the substrate uracil is strongly perturbed by the amino acid residue Ile33, which sandwiches the uracil with His62, through the steric contact due to the thermal motion. As a result, the magnitude of the thermal oscillation of the potential energy and structure of the substrate uracil significantly increases. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
An approximate diatomics in molecules formulation of generalized valence bond theory
Authors: Cullen John
Published: July 2007

The slow computational speed of the generalized valence bond perfect pairing method (GVB‐PP) has been an impediment to its routine use. We have addressed this problem by employing a diatomics in molecules Hamiltonian derived from a second quantization perturbation approach. This results in all three‐ and four‐centered two‐electron integrals being dropped from the traditional GVB‐PP calculation. For moderate sized molecules, as for example C20 computed with a double zeta + polarization basis, there is on average a fifty‐fold decrease in computational times. In this article, we present the theory behind our approach and analyze the accuracy and speed of this approximate GVB‐PP method for several cases where density functional methods have produced ambivalent results. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
Theoretical studies on four‐membered ring compounds with NF2, ONO2, N3, and NO2 groups
Authors: Fan Xiao‐Wei , Ju Xue‐Hai
Published: July 2007

Density functional theory (DFT) method has been employed to study the geometric and electronic structures of a series of four‐membered ring compounds at the B3LYP/6‐311G** and the B3P86/6‐311G** levels. In the isodesmic reactions designed for the computation of heats of formation (HOFs), 3,3‐dimethyl‐oxetane, azetidine, and cyclobutane were chosen as reference compounds. The HOFs for N3 substituted derivations are larger than those of oxetane compounds with ONO2 and/or NF2 substituent groups. The HOFs for oxetane with ONO2 and/or NF2 substituent groups are negative, while the HOFs for N3 substituted derivations are positive. For azetidine compounds, the substituent groups within the azetidine ring affect the HOFs, which increase as the difluoroamino group being replaced by the nitro group. The magnitudes of intramolecular group interactions were predicted through the disproportionation energies. The strain energy (SE) for the title compounds has been calculated using homodesmotic reactions. For azetidine compounds, the NF2 group connecting N atom in the ring decrease the SE of title compounds. Thermal stability were evaluated via bond dissociation energies (BDE) at the UB3LYP/6‐311G** level. For the oxetane compounds, the ONO2 bond is easier to break than that of the ring CC bond. For the azetidine and cyclobutane compounds, the homolysises of CNX2 and/or NNX2 (X = O, F) bonds are primary step for bond dissociation. Detonation properties of the title compounds were evaluated by using the Kamlet–Jacobs equation based on the calculated densities and HOFs. It is found that 1,1‐dinitro‐3,3‐bis(difluoroamino)‐cyclobutane, with predicted density of ca. 1.9 g/cm3, detonation velocity (D) over 9 km/s, and detonation pressure (P) of 41 GPa that are lager than those of TNAZ, is expected to be a novel candidate of high energy density materials (HEDMs). The detonation data of nitro‐BDFAA and TNCB are also close to the requirements for HEDMs. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
Carbon assimilation and dissimilation during growth of Geotrichum candidum on amino acids and glucose
Authors: Aziza Majda , Amrane Abdeltif
Published: July 2007

BACKGROUND: This work examines the metabolic behaviour of amino acids during Geotrichum candidum growth, in the presence of a primary carbon source like glucose. Amino acids were characterized based on their carbon assimilation and dissimilation by G. candidum, in the presence of glucose as the limiting substrate.

RESULTS: The first group (Cys, His, Phe, Thr and Trp) was only used as nitrogen sources by G. candidum, with glucose being the carbon and energy source. Glucose repression was shown for the rest of the amino acids, since only after glucose depletion amino acids from the second group (Gly, Lys, Met, Val) were dissimilated for energy supply by oxidation into CO2, while those from the third group (Ala, Arg, Asp, Glu, Leu, Pro and Ser) were assimilated as carbon sources (and additionally used as nitrogen sources), leading to a diauxic growth.

CONCLUSION: This energy‐saving response was not previously shown for the second fungus involved in ripening of soft white cheese—P. camembertii—leading to simultaneous use of some amino acids and glucose as carbon and energy sources, and hence lower growth rates than those recorded during G. candidum growth. Copyright © 2007 Society of Chemical Industry
Prenatal diagnosis of complete atrioventricular canal associated with tetralogy of Fallot
Authors: Hung Jeng‐Hsiu , Lu Jen‐Her , Hung Chia‐Yi Selena
Published: July 2007

A complete atrioventricular canal defect occurs when an embryonic common atrioventricular valve fails to divide completely into 2 common atrioventricular valves. Tetralogy of Fallot is an abnormal embryologic development in which an unequal conotruncal division results in a small pulmonary artery and a large aortic artery. We report a case of prenatal diagnosis of a complete atrioventricular canal defect associated with tetralogy of Fallot. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2008
Synthesis and analysis of [3H] salmon calcitonin ([3H]SMC021)
Authors: Ciszewska Grazyna , Allentoff Alban , Wu Amy , Ray Tapan
Published: July 2007

Tritium‐labelled salmon calcitonin was synthesized successfully through a 5 step peptide synthesis. LC‐MS performed on each step played an important role for in process control. For accuracy, Q‐TOF MS was used to determine the specific activity of tritiated salmon calcitonin ([3H]SMC021) using the triple charged ion. Copyright © 2007 John Wiley & Sons, Ltd.
SPECT imaging of the α4β2 nicotinic receptor using [5‐123I]A85380
Authors: Pimlott Sally L. , Piggott Margaret , Patterson James , Cavanagh Jonathan , Wyper David J.
Published: July 2007

In order to image nAChR density in vivo in humans, [5‐123I]‐iodo‐3‐[2(S)‐2‐azetidinylmethoxy]pyridine ([5‐123I]A85380) has been developed as a SPECT imaging tracer. This article outlines the radiochemical synthesis, in vitro validation in human post‐mortem tissue and some initial in vivo clinical studies using the ligand [5‐123/125I]A85380. Limitations of the usefulness of the tracer for routine clinical use are also discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis of the myoview™ ligand, [bisphosphinoethane‐1,2‐14C]tetrofosmin
Authors: Woolley Geoffrey T. , Kitson Sean L. , Gordon Reid R.
Published: July 2007

The carbon‐14 radiolabels in [bisphosphinoethane‐1,2‐14C]tetrofosmin ligand were readily introduced by reacting 1,2‐dibromo[U‐14C]ethane with bis(2‐ethoxyethyl)benzylphosphine (1). This was converted to the Myoview™ ligand in an overall yield of 45%. This radiosynthesis was important in obtaining marketing approval from the regulatory authorities and allowed Myoview™ to become one of the main heart imaging agents of today. Copyright © 2007 John Wiley & Sons, Ltd.
Isotopic enrichment enhancement in metabonomic analysis of UPLC–MS data sets
Authors: Athersuch Toby J. , Nicholson Jeremy K. , Wilson Ian D.
Published: July 2007

Isotopic enrichment of compounds dosed in drug metabolism studies greatly enhances the spectroscopic differentiation of xenobiotic and endogenous metabolites. We show the application of13C15N labelling of a model drug (4‐cyanoaniline) as an aid to metabonomic studies of UPLC–MS‐generated metabolic data sets. Copyright © 2007 John Wiley & Sons, Ltd.
Tritium‐labelling via an iridium‐based solid‐phase catalyst
Authors: Hickey Michael J. , Kingston Lee P. , Lockley William J. S. , Allen Paul , Mather Andrew , Wilkinson David. J.
Published: July 2007

A solid‐phase, iridium‐based ortho‐exchange catalyst has been developed, with the aim of producing cleaner, more efficient, systems for tritium and deuterium labelling. The catalyst, which is a solvated polystyrene‐bound triphenylphosphine complex of cyclooctadienyliridium(I) hexafluorophosphate, was evaluated with respect to more conventional catalysts such as CODIr(PPh3)2PF6 and the Crabtree catalyst using simple model compounds as substrates. Labelling of drug candidate molecules proceeds with high regioselectivity and, after a simple filtration step, affords products with high radiochemical purities directly from the exchange reaction. The solid‐phase catalyst functioned well with a variety of traditional directing groups including nitro, amide, benzophenone and N‐heterocycles. Copyright © 2007 John Wiley & Sons, Ltd.