bluuebunny/crossref_metadata_2025 huggingface dataset:
The Preferred Reaction Path for the Oxidation of Methanol by PQQ‐Containing Methanol Dehydrogenase: Addition–Elimination versus Hydride‐Transfer Mechanism
Authors: Leopoldini Monica , Russo Nino , Toscano Marirosa
Published: December 2006

The catalytic oxidation of methanol to formaldehyde by pyrroloquinoline quinone (PQQ)‐containing methanol dehydrogenase (MDH) was investigated at density functional B3LYP level. The still controversial addition–elimination and hydride‐transfer reaction mechanisms were analysed. Computations performed in the gas phase and in the protein environment indicated that both suggested reaction sequences involve very high activation barriers. In this situation, the reactions should have scarce probability to occur and the preference for one of the two paths cannot be stated. Here, we will show how some corrections to the successive steps in the addition–elimination mechanism can sensibly decrease the activation barriers height, making possible the determination of the MDH‐preferred catalytic path.
Immunoaffinity CE in clinical analysis of body fluids and tissues
Authors: Amundsen Lotta K. , Sirén Heli
Published: December 2006

This paper reviews immunoaffinity CE procedures developed since 1998 for drug, hormone, and disease marker analyses of body fluids and tissues. Immunoaffinity CE and related techniques are described. Examples of clinical applications are included.
Nonaqueous capillary electrophoresis in pharmaceutical analysis
Authors: Geiser Laurent , Veuthey Jean‐Luc
Published: December 2006

This review presents different solvents and electrolytes commonly used as BGEs in NACE for the analysis of pharmaceutical compounds. Most NACE applications carried out since 1998 for the analysis of compounds of pharmaceutical interest are presented in four tables: (i) analysis of drugs and related substances, (ii) analysis of chiral substances, (iii) analysis of phytochemical extracts and (iv) analysis of drugs in biological fluids. These selected examples are used to illustrate the interest in NACE versus conventional aqueous CE.
Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips
Authors: Breadmore Michael C.
Published: December 2006

Poor sensitivity is considered to be one of the major limitations of electrophoretic separation methods, particularly when compared to traditional liquid chromatographic techniques. To address this issue, various in‐line preconcentration techniques have been developed over the past 15 years, ranging in power and complexity, and there are now a number of well understood approaches routinely capable of providing a 10 000‐ to 100 000‐fold increase in sensitivity, as well as several that can be pushed above a million. Furthermore, these have been achieved with particularly troublesome and often difficult samples, such as those having high salinity from a biological or environmental origin. This review will discuss the most common methods for improving the sensitivity of CE, CEC and microchip version of these, with particular attention to those approaches developed over the last five years.
Combination of flow injection with electrophoresis using capillaries and chips
Authors: Chen Yonglei , Lü Wenjuan , Chen Xingguo , Hu Zhide
Published: December 2006

The technique of combined flow injection CE (FI‐CE) integrates the essential favorable merits of FI and CE and can significantly expand the application of CE by utilizing the various on‐line sample pretreatments and preconcentration of FI. The basic principles, instrumental developments, and applications of the FI‐CE system from 2004 to 2006 are reviewed. The recent developments and applications of FI‐CE are outlined.
Nonlinear determinism in river flow: prediction as a possible indicator
Authors: Sivakumar Bellie
Published: December 2006

Whether or not river flow exhibits nonlinear determinism remains an unresolved question. While studies on the use of nonlinear deterministic methods for modeling and prediction of river flow series are on the rise and the outcomes are encouraging, suspicions and criticisms of such studies continue to exist as well. An important reason for this situation is that the correlation dimension method, used as a nonlinear determinism identification tool in most of those studies, may possess certain limitations when applied to real river flow series, which are always finite and often short and also contaminated with noise (e.g. measurement error). In view of this, the present study addresses the issue of nonlinear determinism in river flow series using prediction as a possible indicator. This is done by (1) reviewing studies that have employed nonlinear deterministic methods (coupling phase‐space reconstruction and local approximation techniques) for river flow predictions and (2) identifying nonlinear determinism (or linear stochasticity) based on the level of prediction accuracy in general, and on the prediction accuracy against the phase‐space reconstruction parameters in particular (termed as the ‘inverse approach’). The results not only provide possible indications to the presence of nonlinear determinism in the river flow series studied, but also support, both qualitatively and quantitatively, the low correlation dimensions reported for such. Therefore, nonlinear deterministic methods are a viable complement to linear stochastic ones for studying river flow dynamics, if sufficient caution is exercised in their applications and in interpreting the outcomes. Copyright © 2006 John Wiley & Sons, Ltd.
Upregulation of AKT1 protein expression in forskolin‐stimulated macrophage: Evidence from ChIP analysis that CREB binds to and activates the AKT1 promoter
Authors: Misra Uma Kant , Pizzo Salvatore Vincent
Published: December 2006

Recently, we reported that silencing CREB gene expression by RNAi significantly attenuates forskolin‐induced activation of Akt1. We now provide evidence that forskolin‐treatment causes transcriptional and translational upregulation of Akt1 in macrophages. Akt synthesis was demonstrated by [14C]leucine or [35S] incorporation into newly synthesized Akt1 protein. Akt protein levels increased by ∼1.5‐fold after only a 5 min exposure of macrophages to forskolin. Akt1 levels thereafter rapidly returned to basal values (t1/2 ∼ 15 min). Maximal upregulation of Akt1 occurred in cells treated with 10 µM forskolin. Forskolin‐dependent Akt1 synthesis was abolished by pretreating the cells with CREB‐directed dsRNA as demonstrated at both the message and protein level, as well as by determining the synthesis of [35S]‐labeled Akt1 protein. The PKA inhibitor H‐89, greatly attenuated forskolin‐induced Akt1 synthesis. Transcriptional and translational inhibitors also greatly reduced Akt1 synthesis in forskolin‐stimulated [14C]leucine‐labeled macrophages. Using a chromatin immunoprecipitation assay, we demonstrate that CREB binds to a CRE binding domain of the Akt1 gene promoter. In conclusion, we show here for the first time transcriptional upregulation of Akt1 by CREB, based upon Akt1 protein synthesis and its modulation by transitional and translational inhibitors in forskolin‐stimulated cells, Akt1 protein. and mRNA levels upon silencing CREB gene expression, and binding of CREB to the Akt1 gene promoter. J. Cell. Biochem. 100: 1022–1033, 2007. © 2006 Wiley‐Liss, Inc.
Gestational diabetes mellitus: Fetal liver length measurements between 21and 24 weeks' gestation
Authors: Mirghani Hisham , Zayed Reem , Thomas Letha , Agarwal Mukesh
Published: December 2006

Purpose.

To evaluate sonographic measurements of the fetal liver, fetal abdominal fat layer, interventricular septum, and Wharton's jelly area between 21 and 24 weeks' gestation in women with gestational diabetes mellitus (GDM).

Methods.

A total of 123 consecutive healthy pregnant women underwent sonographic examination at 21–24 weeks' gestational age. The measurements included fetal biometry, detailed anomaly scan, and fetal body composition measurements (subcutaneous fat, liver size, cardiac muscle thickness, and Wharton's jelly area). GDM was confirmed by way of a 75‐g oral glucose tolerance test using World Health Organization criteria within 1 week of the examination.

Results.

Nineteen (15.4%) women were diagnosed with GDM, while 104 (84.6%) women were without GDM. The mean fetal liver length was 36 mm (95% CI 32–37) in women with GDM and 31 mm (95% CI 30–33) in women without GDM (p < 0.01). Liver enlargement was related to maternal fasting glucose levels and not 2‐hour postprandial levels. There was no significant difference in the fetal biometric and other fetal body measurements between the 2 groups.

Conclusions.

The findings of this study suggest that midtrimester fetal liver length appears to be longer in GDM than in normal pregnancies. However, the fetal abdominal fat layer, interventricular septum, and Wharton's jelly were not affected. Nevertheless, further, larger randomized studies are required to confirm these findings. © 2006 Wiley Periodicals, Inc. J Clin Ultrasound 2007
Correlated fluorescence lifetime and spectral measurements in living cells
Authors: Spriet Corentin , Trinel Dave , Waharte François , Deslee Didier , Vandenbunder Bernard , Barbillat Jacques , Héliot Laurent
Published: December 2006

Studies of proteins' interaction in cells by FRET can take benefit from two important photo‐physical properties describing fluorescent proteins: fluorescence emission spectrum and fluorescence lifetime. These properties provide specific and complementary information about the tagged proteins and their environment. However, none of them taken individually can completely quantify the involved fluorophore characteristics due to their multiparametric dependency with molecular environment, experimental conditions, and interpretation complexity. A solution to get a better understanding of the biological process implied at the cellular level is to combine the spectral and temporal fluorescence data acquired simultaneously at every cell region under investigation. We present the SLiM‐SPRC160, an original temporal/spectral acquisition system for simultaneous lifetime measurements in 16 spectral channels directly attached to the descanned port of a confocal microscope with two‐photon excitation. It features improved light throughput, enabling low‐level excitation and minimum invasivity in living cells studies. To guarantee a fairly good level of accuracy and reproducibility in the measurements of fluorescence lifetime and spectra on living cells, we propose a rigorous protocol for running experiments with this new equipment that preserves cell viability. The usefulness of SLiM approach for the precise determination of overlapping fluorophores is illustrated with the study of known solutions of rhodamine. Then, we describe reliable FRET experiments in imaging mode realized in living cells using this protocol. We also demonstrate the benefit of localized fluorescence spectrum‐lifetime acquisitions for the dynamic study of fluorescent proteins. proteins. Microsc. Res. Tech., 2007. © 2006 Wiley‐Liss, Inc.
Multiphoton fluorescence lifetime imaging of human hair
Authors: Ehlers Alexander , Riemann Iris , Stark Martin , König Karsten
Published: December 2006

In vivo and in vitro multiphoton imaging was used to perform high resolution optical sectioning of human hair by nonlinear excitation of endogenous as well as exogenous fluorophores. Multiphoton fluorescence lifetime imaging (FLIM) based on time‐resolved single photon counting and near‐infrared femtosecond laser pulse excitation was employed to analyze the various fluorescent hair components. Time‐resolved multiphoton imaging of intratissue pigments has the potential (i) to identify endogenous keratin and melanin, (ii) to obtain information on intrahair dye accumulation, (iii) to study bleaching effects, and (iv) to monitor the intratissue diffusion of pharmaceutical and cosmetical components along hair shafts. Microsc. Res. Tech. 2007. © 2006 Wiley‐Liss, Inc.
Rapid transport of plasmid DNA into the nucleolus via actin depolymerization using the HVJ envelope vector
Authors: Suvanasuthi Saroj , Tamai Katsuto , Kaneda Yasufumi
Published: December 2006

Background

Although nuclear transport of therapeutic genes is an essential requirement of human gene therapy, factors required for nuclear entry of DNA remain to be elucidated. Non‐viral vector systems have led to numerous improvements in the efficiency of delivery of exogenous DNA into cells. However, nuclear transport of plasmid is difficult to achieve.

Methods

We examined nuclear translocation efficiency of Cy3‐labeled plasmid DNA (Cy3‐pDNA) delivered by the hemagglutinating virus of Japan envelope (HVJ‐E) vector, Lipofectamine or microinjection. We also examined the effect of actin depolymerization on nuclear transport of Cy3‐pDNA.

Results

Cy3‐pDNA reached the nucleus, particularly in the nucleolus, in 30 min after fusion‐mediated delivery using the HVJ‐E vector, while the DNA was retained in the cytoplasm during the observed period after the delivery by cationic liposomes. HVJ‐E treatment transiently depolymerized actin filaments, and acceleration of nucleolar entry of microinjected DNA was achieved when treated with either empty HVJ‐E or cytochalasin D, an inhibitor of actin depolymerization, prior to microinjection.

Conclusions

These results suggest that plasmid DNA can be transported rapidly from the cytoplasm to the nucleolus when actin filaments are depolymerized. Thus, the HVJ‐E vector can accelerate the transport of DNA to the nucleolus by actin depolymerization. Copyright © 2006 John Wiley & Sons, Ltd.
M+4 stable isotope labeling of levovirin and M+7 and carbon‐14 labeling of levovirin valinate pro‐drug
Authors: de Keczer Steve A. , Masjedizadeh Mohammad R. , Wu Shao‐Yong , Lara‐Jaime Teresa , Comstock Kate , Dvorak Charles , Liu Yu‐Ying , Berger Walter
Published: December 2006

[M+4]‐labeled levovirin 5 (231 mg) was synthesized as an MS reference compound from [M+4] triazole ester 2. [M+7]‐labeled levovirin valinate 6 (127 mg) was synthesized as a comparison MS reference compound from [M+6] triazole ester 3. [14C]‐Levovirin 7 and [14C]‐levovirin valinate 8 were synthesized to support metabolism studies. The synthesis of 7 was accomplished in 33% overall yield (35.4 mCi, 57 mCi/mmol) from Ba14CO3 and 8 was synthesized in 41% yield (12.5 mCi, 57 mCi/mmol) from 7. An efficient metallation/carbonation reaction was developed to synthesize [14C]‐triazole ester 4. Copyright © 2006 John Wiley & Sons, Ltd.
Simple and high radiochemical yield synthesis of 2′‐Deoxy‐2′‐[18F]fluorouridine via a new nosylate precursor
Authors: Kang Se Hun , Oh Seung Jun , Yoon Mi Kyung , Ryu Jin Sook , Lee Won Koo , Choi Sun Joo , Park Kyung Pae , Moon Dae Hyuk
Published: December 2006

We synthesized 2'‐deoxy‐2'‐[18F]fluorouridine (7) as a radiotracer for positron emission tomography from a new nosylate precursor (6). This new precursor was synthesized from uridine in four steps. The overall synthetic yield was 9.4% and we have high stability of >98% purity up to 6 months at 4°C. The optimal manual [18F]fluorination conditions were 30 mg of the precursor 6 in 500 µl of acetonitrile at 145°C for 15 min with 370 MBq of [18F]fluoride. The [18F]fluorination yield was 76.5±2.7% (n = 3). After hydrolysis of protecting groups with 1 N HCl and purification by HPLC, the overall radiochemical yield and purity were 26.5±1.4% and 98.2±2.5%, respectively. The preparation time was 70.0±10.5 min (n = 3 for each result). We also developed an automated method with a radiochemical yield and purity of 24.0±2.8 and 98.0±1.5% (n = 10) using a GE TracerLab MX chemistry module. This new nosylate precursor for 2'‐deoxy‐2'‐[18F]fluorouridine synthesis showed higher radiochemical yields and reproducibility than previous methods. Copyright © 2006 John Wiley & Sons, Ltd.
Preparation of deuterium‐labeled monounsaturated and saturated fatty acids for use as stable isotope metabolic tracers
Authors: Crane Sheldon N. , Bateman Kevin , Gagne Sebastien , Levesque Jean‐Francois
Published: December 2006

Synthetic routes adaptable to the preparation of a variety of d7‐labeled monounsaturated and saturated fatty acids are reported. Using these reaction sequences, d7‐oleic [18:1 (9c)], d7‐elaidic [18:1 (9t)], and d7‐stearic acid (18:0) were prepared for use in metabolism studies as stable isotope‐labeled tracers. Copyright © 2006 John Wiley & Sons, Ltd.
Radiosynthesis of 3‐(3‐[18F]fluoropropoxy)‐4‐(benzyloxy)‐N‐[(1‐dimethylaminocyclopentyl)methyl]‐5‐methoxybenzamide, a potential PET radiotracer for the glycine transporter GlyT‐2
Authors: Tian Haibin , Vogel Rebecca , Amici Louis , Tamagnan Gilles , Baldwin Ronald M.
Published: December 2006

The recently described selective and potent GlyT2 antagonist, 4‐benzyloxy‐3,5‐dimethoxy‐N‐[(1‐dimethylaminocyclopentyl) methyl]benzamide (IC50=16 nM) provided an important additional tool to further characterize GlyT2 pharmacology. In order to identify an effective PET radioligand for in vivo assessment of the GlyT‐2 transporter, 3‐(3‐[18F]fluoropropoxy)‐4‐(benzyloxy)‐N‐((1‐dimethylaminocyclopentyl) methyl)‐5‐methoxybenzamide ([18F]3), a novel analog of 4‐benzyloxy‐3,5‐dimethoxy‐N‐[(1‐dimethylaminocyclopentyl) methyl]benzamide was synthesized using a one‐pot, two‐step method. The NCA radiofluorination of 1,3‐propanediol di‐p‐tosylate in the presence of K2CO3 and Kryptofix‐222 in acetonitrile gave 81% 3‐[18F]fluoropropyl tosylate, which was subsequently coupled with 4‐benzyloxy‐3‐hydroxy‐5‐methoxy‐N‐[(1‐dimethylaminocyclopentyl) methyl]benzamide in the same reaction vessel. Solvent extraction and HPLC (Eclipse XDB‐C8 column, 80/20/0.1 MeOH/H2O/Et3N, 3.0 ml/min) gave [18F]3 in 98.5% radiochemical purity. The radiochemical yield was determined to be 14.0–16.2% at EOS, and the specific activity was 1462±342 GBq/µmol. The time of synthesis and purification was 128 min. The final product was prepared as a sterile saline solution suitable for in vivo use. Copyright © 2006 John Wiley & Sons, Ltd.
Cine phase contrast MRI to measure continuum Lagrangian finite strain fields in contracting skeletal muscle
Authors: Zhou Hehe , Novotny John E.
Published: December 2006

Purpose

To measure the complex mechanics and Lagrangian finite strain of contracting human skeletal muscle in vivo with cine phase contrast MRI (CPC‐MRI) applied to the human supraspinatus muscle of the shoulder.

Materials and Methods

Processing techniques are applied to transform velocities from CPC‐MRI images to displacements and planar Lagrangian finite strain. An interpolation method describing the continuity of the velocity field and forward‐backward and Fourier transform methods were used to track the displacement of regions of interest during a cyclic abduction motion of a subject's arm. The components of the Lagrangian strain tensor were derived during the motion and principal and maximum in‐plane shear strain fields calculated.

Results

Derived displacement and strain fields are shown that describe the contraction mechanics of the supraspinatus. Strains vary over time during the cyclic motion and are highly nonuniform throughout the muscle.

Conclusion

This method presented overcomes the physical resolution of the MRI scanner, which is crucial for the detection of detailed information within muscles, such as the changes that might occur with partial tears of the supraspinatus. These can then be used as input or validation data for modeling human skeletal muscle. J. Magn. Reson. Imaging 2007. © 2006 Wiley‐Liss, Inc.
Assessment of bolus injection protocol with appropriate concentration for quantitative assessment of pulmonary perfusion by dynamic contrast‐enhanced MR imaging
Authors: Ohno Yoshiharu , Murase Kenya , Higashino Takanori , Nogami Munenobu , Koyama Hisanobu , Takenaka Daisuke , Kawamitu Hideaki , Matsumoto Sumiaki , Hatabu Hiroto , Sugimura Kazuro
Published: December 2006

Purpose

To determine the appropriate concentration for quantitative assessment of dynamic contrast‐enhanced pulmonary MR imaging.

Materials and Methods

A total of 40 consecutive patients with small bronchioalveolar carcinoma underwent perfusion single‐photon emission tomography (SPECT) and three‐dimensional (3D) dynamic MR imaging with a 3D radiofrequency spoiled gradient‐echo sequence. In each patient, 5 mL of contrast media with 0.1, 0.3, and 0.5 mmol/mL were administered at a rate of 5 mL/second. All patients were divided into two groups (<70 kg and ≥70 kg) for assessment of appropriate concentration to quantitatively assess regional perfusion parameter in routine clinical practice. Pulmonary blood flow (PBF) in each protocol was calculated from a signal intensity (SI)–time course curve. Differences and limits of agreement of PBF between dynamic MR imaging (PBFMR) using three different concentrations and perfusion SPECT (PBFSPECT) were statistically compared in both patient groups.

Results

PBFMR using 0.3 mmol/mL in the <70‐kg group and 0.5 mmol/mL in the ≥70‐kg group showed no significant difference compared with PBFSPECT (P > 0.05). Limits of agreements in 0.3 mmol/mL in the <70‐kg group and 0.5 mmol/mL in the ≥70‐kg group were smaller than those of the other concentrations and small enough for clinical purposes.

Conclusion

Appropriate concentrations provide accurate and reproducible assessments of regional pulmonary perfusion parameters on 3D dynamic MR perfusion imaging. We suggest using 5 mL of contrast media with 0.3 mmol/mL for patients weighing less than 70 kg and 0.5 mmol/mL for patients weighing 70 kg or more. J. Magn. Reson. Imaging 2007. © 2006 Wiley‐Liss, Inc.
Small hepatic lesions found on single‐phase helical CT in patients with malignancy: Diagnostic capability of breath‐hold, multisection fluid‐attenuated inversion‐recovery (FLAIR) MR imaging using a half‐fourier acquisition single‐shot turbo spin‐echo (HASTE) sequence
Authors: Sasaki Katsumi , Ito Katsuyoshi , Fujita Takeshi , Shimizu Ayame , Yasui Masayasu , Hayashida Minoru , Tanabe Masahiro , Matsunaga Naofumi
Published: December 2006

Purpose

To evaluate the diagnostic capability of breath‐hold, multisection fluid‐attenuated inversion‐recovery (FLAIR) imaging using a half‐Fourier acquisition single‐shot turbo spin‐echo (HASTE) sequence in combination with T2‐weighted fast spin‐echo (FSE) magnetic resonance (MR) sequences for small hepatic lesions found on CT in patients with malignancy.

Materials and Methods

This study included 48 patients with extrahepatic malignancy who underwent both CT and MR examinations. There were a total of 112 small hepatic lesions (73 cysts and 39 liver metastases, <2 cm in diameter) that showed low attenuation on enhanced CT. Three radiologists independently reviewed the CT and MR (FLAIR‐HASTE and T2‐weighted FSE) images and assigned a confidence level to their evaluation (cyst or metastasis) on a five‐point scale.

Results

All three reviewers were significantly better able (P < 0.05) to differentiate small hepatic cyst from liver metastasis with combined FLAIR‐HASTE and T2‐weighted FSE images (Az values = 0.997–0.999) than with CT (0.917–0.932). The mean values of sensitivity, specificity, and accuracy were significantly higher (P < 0.001) for T2‐weighted FSE with FLAIR‐HASTE (96.6%, 96.8%, and 96.7%, respectively) than for CT (76.9%, 61.6%, and 67.3%, respectively). A confident diagnosis was rendered in 12 of 112 lesions (10.7%) on the basis of CT, and this rate increased to 83 of 112 (74.1%) on the basis of T2‐weighted FSE and FLAIR‐HASTE imaging.

Conclusion

FLAIR‐HASTE is considered to be an effective sequence for differentiating hepatic cysts from liver metastases without the use of a contrast agent. With FLAIR‐HASTE one can confidently diagnose small hepatic lesions found on CT in patients with a malignancy. J. Magn. Reson. Imaging 2007. © 2006 Wiley‐Liss, Inc.
Negative‐charge driven fragmentations for evidencing zwitterionic forms from doubly charged coppered peptides
Authors: Boutin Michel , Bich Claudia , Afonso Carlos , Fournier Françoise , Tabet Jean‐Claude
Published: December 2006

In aqueous solution, amino acids (AA) and peptides are known to exist as zwitterions over a large pH range. However, in the gas phase, i.e. in electrospray (ESI), the zwitterionic form becomes unfavorable owing to the absence of stabilizing effects from intermolecular solvation. Nevertheless, during mass spectrometry experiments, the presence of a metallic cation can reinforce the zwitterionic character of the molecule and thus influence its fragmentation under low energy collision‐induced dissociation (CID) conditions. The [M + CuII]2+ complexes of six pentapeptides (YGGFL, YGGFL(NH2), YGGFK, YGGFQ, KYGGF and QYGGF) were analyzed by collision to highlight the presence of zwitterions. The experiments were performed on a 3D‐ion trap equipped with an orthogonal ESI source. For each peptides studied, negative‐charge driven fragmentations on globally positively charged ions were observed. These fragmentation mechanisms, generally observed in the negative mode, suggest the competitive deprotonation of the C‐terminal carboxylic acid or of the tyrosine side‐chain residue for each peptide studied and thus a zwitterionic form to preserve the charge balance. Moreover, the specific loss of (CH3C6H4O)• characterizes YGGFK compared to YGGFQ and the specific loss of styrene characterizes KYGGF compared to QYGGF. These results allow the differentiation of the two couples of isobaric pentapeptides. An unusual loss of NH4+, which occurred from the N‐terminus, was also observed for YGGFL, YGGFL(NH2), YGGFK and YGGFQ. Finally, the reduction of CuII to CuI, concomitant with the (CH3C6H4O)• release, was pointed out for YGGFK. Copyright © 2006 John Wiley & Sons, Ltd.
Direct analysis of alkaloid profiling in plant tissue by using matrix‐assisted laser desorption/ionization mass spectrometry
Authors: Wu Wei , Liang Zhitao , Zhao Zhongzhen , Cai Zongwei
Published: December 2006

A method for the direct determination of alkaloid profiling in plant tissues by using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) was developed. The alkaloid profiles of the herbs were obtained without the need for complicated sample preparation. Experimental results demonstrated that the direct MALDI‐TOFMS analysis allowed rapid and reliable characterization of the components in plant tissues. Four commonly used Chinese medicinal herbs were studied, including Aconitum Carmichaeli Debx. (Fuzi in Chinese) and Processed Fuzi, for herb differentiation and explanation of the significant difference in their toxicities. The direct analysis method proved valuable for the preliminary study of plant component profiles. The rapid collection of information from the direct analysis on plant tissues could be valuable for supporting the discovery of new compounds and for the quality control of medicinal herbs. Copyright © 2006 John Wiley & Sons, Ltd.
Tandem mass spectrometry of kahalalides: identification of two new cyclic depsipeptides, kahalalide R and S from Elysia grandifolia
Authors: Tilvi Supriya , Naik C. G.
Published: December 2006

Spectra obtained using electrospray ionization mass spectrometry (ESI‐MS) of the mollusk Elysia grandifolia showed a cluster of molecular ion peaks centered at a molecular mass of 1478 Da (kahalalide F, an anticancer agent). Two new molecules, kahalalide R (m/z 1464) and S (m/z 1492) were characterized using tandem mass spectrometry. The mass differences of 14 Da suggest that they are homologous molecules. In addition, previously identified kahalalide D and kahalalide G are also reported. However, the ESI‐MS of the mollusk's algal diet Bryopsis plumosa showed the presence of only kahalalide F. The amino acid sequences of kahalalide R and S are proposed using collision‐induced dissociation (CID) experiments of singly and doubly charged molecular ions and by comparison with the amino acid sequence of kahalalide F. The pathway is presented for the loss of amino acid residues in kahalalide F. It is observed that there is sequential loss of amino acids in the linear peptide chain, but in the cyclic part the ring opens at the amide bond rather than at the lactone linkage, and the loss of amino acid residues is not sequential. The CID experiment of the alkali‐metal‐cationized molecular ions shows that the sodium and potassium ions coordinate to the amide nitrogen/oxygen in the linear peptide chain of the molecule and not to the lactone oxygen of the lactone. In the case of kahalalide D, CID of the protonated peptide opens the depsipeptide ring to form a linear peptide with acylium ion, and fragment ion signals indicate losses of amino acids in sequential order. In this study, tandem mass spectrometry has provided the detailed information required to fully characterize the new peptides. Copyright © 2006 John Wiley & Sons, Ltd.
The tropopause at southern extratropical latitudes: Argentine operational rawinsonde climatology
Authors: Bischoff Susana A. , Canziani Pablo O. , Yuchechen Adrián E.
Published: December 2006

Argentine operational rawinsonde records spanning a 30‐year period (1968–1997) were used to study the climatology of the tropopause from the subtropics to the southern mid‐latitudes, approximately along the 60°W meridian. The thermal tropopause annual cycle as well as its variability was analyzed at three sites: Resistencia (RES), Ezeiza (EZE), and Comodoro Rivadavia (CRD). Single and double tropopause observations were studied, given the comparatively frequent occurrence of double tropopause events at all three sites. The tropopause behavior at RES and CRD is distinct, whereas at EZE it shows a winter evolution similar to the one at CRD and a summer evolution closer to the one at RES, in agreement with the annual evolution of the subtropical jet. The tropopause evolution is discussed under the light of the dynamic climatology of southern South America. In the presence of double tropopause events and in terms of potential temperature, it should be noted that the upper tropopause temperature is close to the 380 K isentropic, i.e. the tropical tropopause layer. Moreover, the lower tropopause and single tropopause events are fairly close together, i.e. coincident with the lowermost stratosphere. Considering previous research and results from the present analysis, a definition of Extratropical Tropopause Layer (ExTL) is introduced in this work. It is proposed that the lowermost stratosphere should be regarded as the ExTL. Copyright © 2006 Royal Meteorological Society
Drought index evaluation for assessing future wheat production in Greece
Authors: Mavromatis T.
Published: December 2006

The main objectives of this study were (1) to evaluate the SPI, and three variations of the Palmer Drought Severity Index (PDSI) (the original PDSI (Orig‐PDSI), a self‐calibrated version (SC‐PDSI) and a modified scheme employing Priestlay–Taylor's approach to compute potential evapotranspiration (PET) instead of Thornthwaite's method) and their respective moisture anomaly indices for assessing rainfed common wheat and durum wheat yield in two pilot crop regions in north and central Greece, and (2) to assess the vulnerability of wheat production to climate change, using the most appropriate drought index, with future scenarios provided by the Hadley Centre regional climate model HadRM3. The yield models that performed best at high‐drought risk years (the Orig‐PDSI index in the northern region and the SC‐PDSI in the southern region, explaining 82.5 to 84.7% and 92% of the measured yield variability, respectively) were also the most effective at predicting the observed wheat yields when soil moisture was not an important yield‐limiting factor. However, the strength of the relationship between the drought indices and the crop yields was much weaker. Improving the representation of PET in the PDSI algorithm did not improve the model's performance. The sensitivity of the two types of wheat to HadRM3 projections for the high‐drought risk years differed dramatically between the two pilot districts, with extremely decreased yields of 3.14 tn ha−1 expected in the southern district and much smaller changes expected in the northern district (−4.6 vs + 6.7% for durum wheat and common wheat, respectively). For the low‐drought risk years, the yield models in the northern region predicted lower yields by 30 to 60 kg ha−1. A positive yield response by 30 kg ha−1 was found for the southern district. Copyright © 2006 Royal Meteorological Society
Detecting trends in tropical rainfall characteristics, 1979–2003
Authors: Lau K.‐M. , Wu H.‐T.
Published: December 2006

Analyses of two state‐of‐the‐art, blended space‐based and ground‐based global rainfall data sets from the Global Precipitation Climatology Project (GPCP) and the Climate Prediction Center Merged Analysis Product (CMAP) reveal that there was a significant shift in the probability distribution functions of tropical rainfall during the period 1979–2003. This shift features a positive trend in the occurrence of heavy (top 10% by rain amount) and light (bottom 5%) rain events in the tropics during 1979–2003 and a negative trend in moderate (25–75%) rain events. These trends are consistent in both data sets and are in overall agreement with the Climate Research Unit's (CRU) gauge‐only rainfall data over land. The relationships among the trends and the possible long‐term changes in rainfall characteristics are discussed. Copyright © 2006 Royal Meteorological Society
A lacustrine record of early Holocene watershed events and vegetation history, Corvara in Badia, Dolomites (Italy)
Authors: Borgatti Lisa , Ravazzi Cesare , Donegana Marta , Corsini Alessandro , Marchetti Mauro , Soldati Mauro
Published: December 2006

The early–middle Holocene lacustrine succession of Corvara in Badia (Italian Dolomites, 1521 m a.s.l.) records landslides and other watershed events before the onset of human pressure. The sensitivity of this archive to relate climate change, watershed processes and vegetation dynamics in the catchment has been explored through a stratigraphic study, including the analysis of sedimentological features, magnetic properties, palaeobotanical records and radiocarbon dating. A palaeolake existed between 10.1 k and 7 k cal. yr BP and was surrounded by a dense conifer forest. Long‐term forest dynamics driven by ecological processes and by climatic conditions favourable to upward forest expansion is recorded throughout the pollen record. Within the fine clastic sedimentation, distinct layers enriched in organic debris of terrestrial origin have been attributed to instant events produced by mass movements. Their age fits the chronology of large landslide events already known in the catchment, enabling correlation of the field evidence of landslides with the lacustrine record. Landslide frequency is controlled by geological and structural factors, but it is significantly modulated by the centennial–millennial climatic phases that characterise the Holocene in the Alps. The taphonomical properties of pollen and macroremains provided valuable insight on the mechanism of watershed processes. Copyright © 2006 John Wiley & Sons, Ltd.
Food additives characterization by infrared, Raman, and surface‐enhanced Raman spectroscopies
Authors: Podstawka Edyta , Światłowska Małgorzata , Borowiec Ewa , Proniewicz Leonard M.
Published: December 2006

Fourier‐transform infrared (FT‐IR), Raman (RS), and surface‐enhanced Raman scattering (SERS) spectra of β‐hydroxy‐β‐methylobutanoic acid (HMB), L‐carnitine, and N‐methylglycocyamine (creatine) have been measured. The SERS spectra have been taken from species adsorbed on a colloidal silver surface. The respective FT‐IR and RS band assignments (solid‐state samples) based on the literature data have been proposed. The strongest absorptions in the FT‐IR spectrum of creatine are observed at 1398, 1615, and 1699 cm−1, which are due to νs(COOH) + ν(CN) + δ(CN), ρs(NH2), and ν(CO) modes, respectively, whereas those of L‐carnitine (at 1396/1586 cm−1 and 1480 cm−1) and HMB (at 1405/1555/1585 cm−1 and 1437–1473 cm−1) are associated with carboxyl and methyl/methylene group vibrations, respectively. On the other hand, the strongest bands in the RS spectrum of HMB observed at 748/1442/1462 cm−1 and 1408 cm−1 are due to methyl/methylene deformations and carboxyl group vibrations, respectively. The strongest Raman band of creatine at 831 cm−1 (ρw(RNH2)) is accompanied by two weaker bands at 1054 and 1397 cm−1 due to ν(CN) + ν(RNH2) and νs(COOH) + ν(CN) + δ(CN) modes, respectively. In the case of L‐carnitine, its RS spectrum is dominated by bands at 772 and 1461 cm−1 assigned to ρr(CH2) and δ(CH3), respectively.

The analysis of the SERS spectra shows that HMB interacts with the silver surface mainly through the COO−, hydroxyl, and CH2 groups, whereas L‐carnitine binds to the surface via COO− and N+(CH3)3 which is rarely enhanced at pH = 8.3. On the other hand, it seems that creatine binds weakly to the silver surface mainly by NH2, and CO from the COO− group. Copyright © 2006 John Wiley & Sons, Ltd.
Detailed 1D/2D NMR Analyses of Benzophenone‐Related Reaction Products from a Photopolymerization System of Vinyl Acetate and Benzophenone
Authors: Kong Lingbing , Deng Jianping , Yang Wantai
Published: December 2006

Summary: A new reaction system was designed in order to allow the reaction between benzophenone (BP) and poly(vinyl acetate) chain/radical or monomer to progress under UV irradiation with relatively constant intensity of absorbed light. After the reaction, most BP‐related products were successfully separated and were directly and particularly studied for the first time by a 600 MHz solution‐state NMR spectrometer. 13C, 1H, DEPT‐135, and 2D 1H‐13C HSQC, 1H‐13C HMBC NMR spectra were utilized for the analyses. In the mixed products, two new structures with new ether groups were detected and confirmed, besides detailed confirmation of benzopinacol and semi‐benzopinacol‐connected poly(vinyl acetate).

Structures 1 and 2

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Structures 1 and 2
White‐Light Emission from a Single Polymer with Singlet and Triplet Chromophores on the Backbone
Authors: Zhen Hongyu , Xu Wei , Yang Wei , Chen Qiliang , Xu Yunhua , Jiang Jiaxing , Peng Junbiao , Cao Yong
Published: December 2006

Summary: A strategy to generate an efficient white‐light emission has been developed by mixing fluorescence and phosphorescence emission from a single polymer. Fluorene is used as the blue‐emissive component, benzothiadiazole (BT) and the iridium complex [(btp)2Ir(tmd)] are incorporated into a polyfluorene backbone, respectively, as green‐ and red‐emissive chromophores by Suzuki polycondensation. By changing the contents of BT and [(btp)2Ir(tmd)] in the polymer, the electroluminescence spectrum from a single polymer can be adjusted to achieve white‐light emission. A white polymeric light‐emitting diode (WPLED) with a structure of ITO/PEDOT:PSS/PVK/PFIrR1G03/CsF/Al shows a maximum external quantum efficiency of 3.7% and the maximum luminous efficiency of 3.9 cd · A−1 at the current density of 1.6 mA · cm−2 with the CIE coordinates of (0.33, 0.34). The maximum luminance of 4 180 cd · m−2 is achieved at the current density of 268 mA · cm−2 with the CIE coordinates of (0.31, 0.32). The white‐light emissions from such polymers are stable in the white‐light region at all applied voltages, and the electroluminescence efficiencies decline slightly with the increasing current density, thus indicating that the approach of incorporating singlet and triplet species into the polymer backbone is promising for WPLEDs.

Structure of PFIrR1G04 and the EL spectra of its devices under various voltages. Device structure: ITO/PEDOT:PSS/PVK/polymer/CsF/Al.

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Structure of PFIrR1G04 and the EL spectra of its devices under various voltages. Device structure: ITO/PEDOT:PSS/PVK/polymer/CsF/Al.
High‐resolution 3D arteriography of chronic total peripheral occlusions using a T1‐W turbo spin‐echo sequence with inner‐volume imaging
Authors: Sampath Smita , Raval Amish N. , Lederman Robert J. , McVeigh Elliot R.
Published: December 2006

Percutaneous revascularization of peripheral artery chronic total occlusion (CTO) is challenging under X‐ray guidance without direct image feedback, due to poor visualization of the obstructed segment and underappreciation of vessel tortuosity. Operators are required to steer interventional devices relatively “blindly,” and therefore procedural failure or perforation may occur. Alternatively, MRI may allow complete visualization of both patent and occluded arterial segments. We designed and implemented a 3D high‐resolution, T1‐weighted (T1‐W) turbo spin‐echo (TSE) MRI sequence with inner‐volume (IV) imaging to enable detailed peripheral artery CTO imaging. Using this sequence, high‐resolution volumes of interest (VOIs) around the vessel were achieved within 5−10 min. This imaging approach may be used for rapid pre‐ and postprocedural evaluations, and as a 3D roadmap that can be overlaid during real‐time X‐, MR‐, or XMR‐guided catheterization. Experiments were successfully performed on a carotid CTO model in swine ex vivo, and in peripheral arteries in normal volunteers and patients in vivo. Delineation of the vascular architecture, including contrast differences between the patent and occluded artery segments, and lesion morphology heterogeneity were visualized. Magn Reson Med 57:40–49, 2007. Published 2006 Wiley‐Liss, Inc.
Metabolic characterisation of plasma in juveniles with glycogen storage disease type 1a (GSD1a) by high‐resolution 1H NMR spectroscopy
Authors: Duarte Iola F. , Goodfellow Brian J. , Barros António , Jones John G. , Barosa Cristina , Diogo Luisa , Garcia Paula , Gil Ana M.
Published: December 2006

This paper reports the first application of high‐resolution 1H NMR spectroscopy to the plasma of five juveniles with glycogen storage disease type 1a (GSD1a), permitting the characterisation of the plasma metabolic profile and the identification of alterations relative to a set of control samples. The relaxation‐weighted spectra allowed changes in low molecular weight compounds to be detected more clearly, whereas diffusion‐edited spectra were used to characterise the plasma lipoprotein profile. Low molecular weight metabolites with altered levels in most patients were lactate, ketone bodies, acetate, creatine/creatinine and glucose. One of the patients showed distinctively lower glucose levels and higher lactate and ketone body contents, suggesting poorer metabolic control of the disease compared with other patients. In addition, a metabolite tentatively identified as α‐hydroxyisobutyrate was only detected in the spectra of GSD1a plasmas, representing, therefore, a possible novel GSD1a biomarker. Total lipoprotein contents were higher in the plasma from GSD1a patients. Furthermore, lower HDL and higher VLDL + LDL levels also characterised the plasma of these patients. Preliminary results on principal component analysis of 1H NMR spectra allowed a clear separation between GSD1a and control plasmas. The specificity of the changes observed to GSD1a is discussed, together with the recognised potential of NMR and pattern recognition methods for aiding the diagnosis of GSD1a. Copyright © 2006 John Wiley & Sons, Ltd.
Thalassemia: macroscopic and radiological study of a case
Authors: Lagia A. , Eliopoulos C. , Manolis S.
Published: December 2006

Differentiation of the genetic and the acquired anaemias, particularly in areas of the world where they may co‐exist, has been a challenge for palaeopathologists for over 100 years. In this paper we present macroscopic and radiographic skeletal lesions that are associated with the thalassemias in a 14‐year‐old girl from a modern reference collection of the University of Athens. This individual is of known sex, age, cause of death, place and dates of birth and death. The case is examined in terms of epidemiology, growth, distribution and severity of lesions and differential diagnosis. The entire skeleton is affected by marrow hyperplasia: lesions of the axial skeleton are extreme, and the appendicular skeleton is severely affected as well. The odontofacial manifestations that are diagnostic of thalassemia and differentiate it from other anaemias are present and include: maxillary and mandibular hyperplasia, reduced sinuses, displacement of maxillary dental structures, overbite, and generalised osteopenia. The development of extreme bone lesions and the ‘advanced’ age‐at‐death of this individual is explained as either the result of thalassemia major under a low transfusion regimen that was the norm during her lifetime, or to a form of thalassemia intermedia that allows survival to later life at the expense of gross skeletal alterations. The present status of skeletal studies in Greece does not support the identification of a genetic anaemia in past populations. The potential contribution of the current analysis in differentiating the anaemias in antiquity is evaluated. Copyright © 2006 John Wiley & Sons, Ltd.
Grass fiber reinforced phenol formaldehyde resin composite: preparation, characterization and evaluation of properties of composite
Authors: De Debasish , Adhikari Basudam , De Debapriya
Published: December 2006

There is a growing interest in the development of new materials through utilization of natural resources. This paper describes evaluation of water leached and alkali treated chopped grass fiber reinforced phenol formaldehyde composite. Here alkali treatment of grass fiber was carried out by varying the concentration of sodium hydroxide. The thermal stability of the composite was assessed by thermogravimetric analysis (TGA). Fourier transformation infrared spectroscopic study of both water leached and alkali treated grass fiber‐phenolic resin composite was also performed. Water absorption and swelling behavior of grass fiber phenolic resin composites in water were studied and the alkali treated grass fiber‐resin composite showed less water absorption and swelling. A composite prepared from 1% alkali treated grass fiber and 55% resin, showed the highest tensile strength whereas a composite prepared from 5% alkali treated grass fiber and 55% resin, showed maximum flexural properties. Copyright © 2006 John Wiley & Sons, Ltd.
pH‐sensitive liposome retaining Fe‐porphyrin as SOD mimic for novel anticancer drug delivery system
Authors: Kawakami Hiroyoshi , Hiraka Kazue , Tamai Miho , Horiuchi Aiko , Ogata Akihiko , Hatsugai Tomomi , Yamaguchi Aritomo , Oyaizu Kenichi , Yuasa Makoto
Published: December 2006

In this article the novel design of an anticancer drug delivery system is reported based on a pH‐sensitive liposome retaining the Fe‐porphyrin as a superoxide dismutase(SOD) mimic. The liposomes contained cationic/anionic lipid combinations and were composed of Fe‐porphyrin, L‐α‐phosphatidylcholine (DMPC), dimethylditetradecylammonium bromide (DTDAB), sodispdum oleate (OANa), and Tween‐80. The size of the liposome was approximately 30 nm. The EC50 value (the effective concentration of compound required to produce a 50% lethal dose against cells) of the liposome was found to be significantly smaller than that of cisplatin as the control drug, suggesting that the liposome showed a high cytotoxicity toward the cancer cells. This is due to the fact that the pH‐sensitive liposome rapidly corresponds to the acidic environments of the endosomes and is unstable, and the Fe‐porphyrin is delivered into the cytosol. This result suggests that O may be useful as a target molecule to induce the selective death of cancer cells and that a pH‐sensitive liposome retaining Fe‐porphyrin as an SOD mimic is a new class of anticancer agent. Copyright © 2006 John Wiley & Sons, Ltd.