bluuebunny/crossref_metadata_2025 huggingface dataset:
Heavy‐Metal‐Ion Capture, Ion‐Exchange, and Exceptional Acid Stability of the Open‐Framework Chalcogenide (NH4)4In12Se20
Authors: Manos Manolis J. , Malliakas Christos D. , Kanatzidis Mercouri G.
Published: November 2006

The hydrothermal synthesis of the purely inorganic open‐framework indium selenide (NH4)4In12Se20 (1) is reported. Compound 1 exhibits a unique three‐dimensional open‐framework structure. The framework of 1 shows an unusual, for a chalcogenide compound, rigidity arising from the unprecedented connection mode of its building blocks. Compound 1 possesses ion exchange capacity for Cs+, Rb+, NH4+, but it has selectivity against Na+ and Li+. It also showed exceptional stability in relatively concentrated hydrochloric acid. Ion exchange of 1 with hydrochloric water solutions can produce its solid acid analogue H2(NH4)2In12Se20. The maximum cation‐exchange capacity of 1 was found equal to two equivalents per mol, which is consistent with an exchange mechanism taking place in the 1D‐channels formed by the largest cavities. In addition, 1 can do ion‐exchange with heavy‐metal ions like Hg2+, Pb2+, and Ag+. The capacity of 1 to clean water solutions from heavy‐metal ions was preliminarily investigated and found very high. Specifically, 1 can remove 99.9 % of Hg2+, 99.8 % of Ag+, and 94.9 % of Pb2+ from aqueous solutions of each of these ions. Using different synthetic conditions, we isolated compound (NH4)2In12Se19 (2), which also has as good an acid stability as 1, but no ion‐exchange properties. Overall, this work provides new hydrothermal synthetic approaches for isolation of all‐inorganic open‐framework chalcogenides.
Enriched expression and developmental regulation of the middle‐weight neurofilament (NF‐m) gene in song control nuclei of the zebra finch
Authors: Velho Tarciso A.F. , Lovell Peter , Mello Claudio V.
Published: November 2006

Songbirds evolved a complex set of dimorphic telencephalic nuclei that are essential for the learning and production of song. These nuclei, which together make up the oscine song control system, present several neurochemical properties that distinguish them from the rest of the telencephalon. Here we show that the expression of the gene encoding the middle‐weight neurofilament (NF‐M), an important component of the neuronal cytoskeleton and a useful tool for studying the cytarchitectonic organization of mammalian cortical areas, is highly enriched in large neurons within pallial song control nuclei (nucleus HVC, robustus nucleus of the arcopallium, and lateral magnocellular nucleus of the nidopallium) of male zebra finches (Taeniopygia guttata). We also show that this transcript is highly expressed in large neurons in the medulla, pons, midbrain, and thalamus. Moreover, we demonstrate that NF‐M expression in song control nuclei changes during postembryonic development, peaking during an early phase of the song‐learning period that coincides with the maturation of the song system. We did not observe changes in NF‐M expression in auditory areas or in song control nuclei in the contexts of hearing song or singing, although these contexts result in marked induction of the transcription factor ZENK. This observation suggests that NF‐M might not be under the regulatory control of ZENK in auditory areas or in song control nuclei. Overall, our data indicate that NF‐M is a neurochemical marker for pallial song control nuclei and provide suggestive evidence of an involvement of NF‐M in the development and/or maturation of the oscine song control system. J. Comp. Neurol. 500:477–497, 2007. © 2006 Wiley‐Liss, Inc.
Motoneurons of the flight power muscles of the blowfly Calliphora erythrocephala: Structures and mutual dye coupling
Authors: Schlurmann M. , Hausen K.
Published: November 2006

The morphologies of the motoneurons of the dorsolongitudinal and the three dorsoventral flight power muscles (DLM, DVM 1–3) of Calliphora were investigated by means of cobalt backfills and intracellular biocytin stainings. The DLM is innervated by four prothoracic motoneurons supplying the four ventral muscle fibers and one mesothoracic motoneuron supplying the two dorsal fibers. The three fibers of the DVM 1 and the two fibers of the DVM 2 are innervated by five mesothoracic motoneurons, whereas the two fibers of the DVM 3 are innervated by two prothoracic motoneurons. In general, the motoneurons of each muscle have a common ventral soma cluster located in a characteristic position on the ipsilateral side of the thoracic ganglion, show similar dendritic arborizations in the mesothoracic wing neuropil, and have the same axon pathway. Only the soma of the common motoneuron of two dorsal fibers of the DLM is situated dorsally in the contralateral hemiganglion. The motoneurons of each muscle were found to be strongly dye coupled with each other, indicating that they are connected by gap junctions. In addition, the motoneurons of each muscle establish characteristic coupling patterns with the motoneurons of the other flight power muscles on both sides of the thorax and with two bilateral groups of local mesothoracic interneurons. The revealed coupling patterns are assumed to be of major relevance for the generation the characteristic, rhythmic flight activity of the motoneurons described in previous studies. J. Comp. Neurol. 500:448–464, 2007. © 2006 Wiley‐Liss, Inc.
Postsynaptic targets of somatostatin‐containing interneurons in the rat basolateral amygdala
Authors: Muller Jay F. , Mascagni Franco , McDonald Alexander J.
Published: November 2006

The basolateral amygdala contains several subpopulations of inhibitory interneurons that can be distinguished on the basis of their content of calcium‐binding proteins or peptides. Although previous studies have shown that interneuronal subpopulations containing parvalbumin (PV) or vasoactive intestinal peptide (VIP) innervate distinct postsynaptic domains of pyramidal cells as well as other interneurons, very little is known about the synaptic outputs of the interneuronal subpopulation that expresses somatostatin (SOM). The present study utilized dual‐labeling immunocytochemical techniques at the light and electron microscopic levels to analyze the innervation of pyramidal cells, PV+ interneurons, and VIP+ interneurons in the anterior basolateral amygdalar nucleus (BLa) by SOM+ axon terminals. Pyramidal cell somata and dendrites were selectively labeled with antibodies to calcium/calmodulin‐dependent protein kinase II (CaMK); previous studies have shown that the vast majority of dendritic spines, whether CAMK+ or not, arise from pyramidal cells. Almost all SOM+ axon terminals formed symmetrical synapses. The main postsynaptic targets of SOM+ terminals were small‐caliber CaMK+ dendrites and dendritic spines, some of which were CaMK+. These SOM+ synapses with dendrites were often in close proximity to asymmetrical (excitatory) synapses to these same structures formed by unlabeled terminals. Few SOM+ terminals formed synapses with CaMK+ pyramidal cell somata or large‐caliber (proximal) dendrites. Likewise, only 15% of SOM+ terminals formed synapses with PV+, VIP+, or SOM+ interneurons. These findings suggest that inhibitory inputs from SOM+ interneurons may interact with excitatory inputs to pyramidal cell distal dendrites in the BLa. These interactions might affect synaptic plasticity related to emotional learning. J. Comp. Neurol. 500:513–529, 2007. © 2006 Wiley‐Liss, Inc.
Dynamics of bidirectional transport ofArcmRNA in neuronal dendrites
Authors: Dynes Joseph L. , Steward Oswald
Published: November 2006

The mRNA for Arc (activity‐regulated cytoskeletal protein) is delivered into dendrites and localizes selectively at active synapses. Here we use a green fluorescent protein‐based labeling system and confocal microscopy to define the transport kinetics of exogenously expressed mRNA from chimaericArcconstructs (Arc/MS2 mRNA) in the dendrites of living rat neurons in culture. Arc/MS2 mRNA assembles into particles that move independently, bidirectionally, and intermittently in a fashion indicative of transport. Transport velocities range from below 6 to 65 μm/minute, which is consistent with actin‐based and microtubule‐based transport, respectively. In general, orthograde translocations are longer than retrograde translocations. Rapidly translocating Arc/MS2 mRNA particles sometimes reverse direction and decrease velocity just before stopping, suggesting that local signals regulateArcmRNA targeting movements. These observations identify several phases ofArcmRNA movement that serve as potential points for regulatingArcmRNA localization. J. Comp. Neurol. 500:433–447, 2007. © 2006 Wiley‐Liss, Inc.
Environmental compensation in Swedish road planning
Authors: Rundcrantz Kristina
Published: November 2006

Environmental compensation has been discussed in Europe for a long time and in the Swedish context for almost a decade, but it was not until the latest environmental legislation came into force in 1999 that it became easier to formally require compensation for loss of environmental value. The use of compensation can be one method in trying to reach a more sustainable development. The work with EIA for roads ensures that avoidance of damage to nature is given serious attention. Still, impacts that could require compensation measures will remain. This paper examines 15 planned Swedish state road projects in order to investigate the intended use of environmental compensation. The analysis serves to point out problems and opportunities for improvement to facilitate the use of compensation. The results show that while environmental compensation is proposed in several projects, measures are seldom explicitly documented or interpreted as compensation measures. The planning process also needs to be better coordinated. The most explicitly described environmental compensation in the Swedish projects is connected to water issues, while compensation for impacts in small biotopes is rare. The proposed measures are almost never in sufficient proportion to the damage that is caused. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
Effect of storage of olive mill wastewaters on hydroxytyrosol concentration
Authors: Feki Mongi , Allouche Noureddine , Bouaziz Mohamed , Gargoubi Adel , Sayadi Sami
Published: November 2006

This investigation was designed to determine the effect of olive mill wastewaters (OMW) storage on the continuous extraction of potentially high‐added‐value phenolic compounds from these effluents. Particular emphasis was made on the extraction of hydroxytyrosol, one of the major compounds occurring in OMW. The hydroxytyrosol concentration was constant in OMW supplemented with 10% ethanol during storage. However, with 5 and 0% ethanol, a noticeable increase was observed in the hydroxytyrosol concentration. At time zero, the main polyphenols detected in two samples of fresh OMW without ethanol addition were hydroxytyrosol, hydroxytyrosol‐4‐β‐glucoside, 3,4‐dihydroxyphenylacetic acid, p‐coumaric acid, ferulic acid, oleuropein, and some other unidentified compounds. After 5 months of storage, significant accumulation of hydroxytyrosol was observed. The corresponding concentration increased from 0.98 to 3.5 g/L for the OMW sample collected in November 2004 and from 0.77 to 3.1 g/L for the sample collected in January 2006. However, the concentrations of the other phenolic compounds were markedly decreased. Furthermore, it was deduced that the OMW storage facilitates the continuous extraction procedure and improves the extraction yield of hydroxytyrosol. This last parameter increased from 85.5 to 96.8%.
Effect of fatty acids and tocopherols on the oxidative stability of vegetable oils
Authors: Kamal‐Eldin Afaf
Published: November 2006

The oxidative stability of vegetable oils is determined by their fatty acid composition and antioxidants, mainly tocopherols but also other non‐saponifiable constituents. The effect of fatty acids on stability depends mainly on their degree of unsaturation and, to a lesser degree, on the position of the unsaturated functions within the triacylglycerol molecule. Vegetable oils contain tocopherols and tocotrienols, especially α‐ and γ‐tocopherols, as their main antioxidants. The antioxidant behavior of tocopherols represents a complex phenomenon as they are efficient antioxidants at low concentrations but they gradually lose efficacy as their concentrations in the vegetable oils increase. The “loss of efficacy” of tocopherols, sometimes referred to as a “pro‐oxidant effect”, is witnessed by an increase in the rate of oxidation during the induction period, despite elongation of this phase. The phenomenon is much obvious for α‐tocopherol, but is also evident for other tocopherols. In agreement with nature's wisdom, the tocopherol levels in vegetable oils seem to be close to the optimal levels needed for the stabilization of these oils. The presence of other antioxidants in the oils, e.g. carotenoids, phenolic compounds, and Maillard reaction products, may synergize with tocopherols and minimize this loss of efficacy.
Poly(methyl methacrylate) CE microchips replicated from poly(dimethylsiloxane) templates for the determination of cations
Authors: Qu Song , Chen Xiaohong , Chen Di , Yang Penyuan , Chen Gang
Published: November 2006

A novel method for the rapid fabrication of poly(methyl methacrylate) (PMMA) microfluidic chips using poly(dimethylsiloxane) (PDMS) templates has been demonstrated. The PDMS molds were fabricated by soft lithography. The dense prepolymerized solution of methyl methacrylate containing thermal and UV initiators was allowed to polymerized between a PDMS template and a piece of a 1 mm thick commercial PMMA plate under a UV lamp. The images of microchannels on the PDMS template were precisely replicated into the synthesized PMMA substrates during the UV‐initiated polymerization of the prepolymerized solution on the surface of the PMMA plate at room temperature. The polymerization could be completed within 10 min under ambient temperature. The chips were subsequently assembled by thermal bonding of the channel plate and the cover sheet. The new fabrication method obviates the need for specialized replication equipment and reduces the complexity of prototyping and manufacturing. Nearly 20 PMMA chips were replicated using a single PDMS mold. The attractive performance of the new microfluidic chips has been demonstrated by separating and detecting cations in connection with contactless conductivity detection. The fabricated PMMA microchip has also been successfully employed for the determination of potassium and sodium in environmental and biological samples.
Field simultaneous measurements, modeling, and simulation of harmonic components in a small generation‐transmission network
Authors: Ríos M S. , Raineri B R. , Fuster F J. , Dán A. , Czira Z.
Published: November 2006

This paper presents a detailed deterministic model for a small electrical transmission network (110 kV), representing a large (150 MVA) industrial Copper mine production plant. This model is developed and validated with simultaneous field measurements. The network topology allows two operating modes, ring and open ring operation, without disturbing the busbar loads. Experimental results of—simultaneous—measurements at the three load busbars confirm the simulation results obtained with a state space deterministic model. A sensitivity assessment of busbar harmonic distortions, based on singular and eigenvalues analysis, is also presented. Copyright © 2006 John Wiley & Sons, Ltd.
Explorative two‐locus linkage analysis suggests a multiplicative interaction between the 7q32 and 16p13 myoclonic seizures‐related photosensitivity loci
Authors: Pinto Dalila , Kasteleijn‐Nolst Trenité Dorothée G.A. , Cordell Heather J. , Mattheisen Manuel , Strauch Konstantin , Lindhout Dick , Koeleman Bobby P.C.
Published: November 2006

In traits suspected to be governed by at least two loci, linkage analysis incorporating the joint action of both loci may improve the power to detect linkage, increase the precision of estimating locus positions and provide insight into the underlying etiological mechanism. Recently, we mapped two susceptibility loci for epilepsy‐related photosensitivity (or photoparoxysmal response, PPR) at regions 7q32 (PPR1) and 16p13 (PPR2) in PPR families with prominent myoclonic seizures background (MS‐related PPR). To follow‐up these results and evaluate interaction effects between these regions, we conducted two‐locus (2L) linkage analyses using parametric and non‐parametric methods. The 2L linkage was calculated under a multiplicative (MULT) epistasis model, encompassing models where each locus is necessary but not sufficient for MS‐related PPR and a heterogeneity (HET) model, encompassing models in which each locus is by itself sufficient but not necessary for MS‐related PPR expression. We found maximal 2L linkage under the (MULT) model, which was significantly better than the 2L linkage under the (HET) model (P = 0.001). The 2L analyses gave no increase in power to detect linkage over the single‐locus analyses nor did they improve location estimates at PPR1 and PPR2, as expected under a best‐fit 2L (MULT) model in an affecteds‐only analysis. Our findings suggest that the genes underlying the PPR1 and PPR2 susceptibility loci may have similar functions or act in the same biochemical pathway. Genet. Epidemiol. © 2006 Wiley‐Liss, Inc.
Retropharyngeal node metastasis from papillary thyroid carcinoma
Authors: Otsuki Naoki , Nishikawa Tasuku , Iwae Shigemichi , Saito Miki , Mohri Mitsuhiro , Nibu Ken‐ichi
Published: November 2006

Background.

Papillary thyroid carcinomas commonly metastasize to paratracheal and jugular lymph nodes. Metastasis to the retropharyngeal node is rare for this tumor.

Methods.

Five patients underwent surgical treatment for metastasis of thyroid papillary carcinoma to the retropharyngeal lymph nodes that presented as a parapharyngeal or retropharyngeal mass. All patients had a history of total or subtotal thyroidectomy as their initial treatment. Among them, 3 patients had undergone ipsilateral modified radical neck dissection at their initial treatment. The other 2 patients had a history of bilateral or ipsilateral modified neck dissection for their subsequent cervical lymph node metastases.

Results.

Metastatic retropharyngeal nodes were successfully resected via transcervical approach in all patients. Although aspiration and difficulty in swallowing were observed in 2 patients after surgical treatment for metastatic retropharyngeal nodes, these complications spontaneously resolved within a few months.

Conclusions.

This study suggests that neck dissection and/or metastatic cervical lymph nodes might alter the direction of lymphatic drainage to the retrograde fashion, resulting in the unusual metastasis to the retropharyngeal lymph nodes. Although the cases described here are rare, metastasis to the retropharyngeal node should be considered at the follow‐up for thyroid papillary carcinoma. Because these metastases will be missed by routine ultrasonography of the neck, periodic CT scan or MRI is recommended for follow‐up, especially for patients with a history of neck dissection. © 2006 Wiley Periodicals, Inc. Head Neck, 2007
Serving two organizations: Exploring the employment relationship of contracted employees
Authors: Coyle‐Shapiro Jacqueline A‐M , Morrow Paula C. , Kessler Ian
Published: November 2006

Although growth has occurred in contract employment arrangements both in the public and private sectors, scant research has been conducted on the organizations and employees affected by these arrangements.This study examines the employment relationship of long‐term contracted employees using a social exchange framework. Specifically, we examine the effects of employee perceptions of organizational support from contracting and client organizations on their (a) affective commitment to each organization and (b) service‐oriented citizenship behavior. We also examine whether felt obligation toward each organization mediates this relationship. Our sample consists of 99 long‐term contracted employees working for four contracting organizations that provide services to the public on behalf of a municipal government. Results indicate that the antecedents of affective commitment are similar for the client and contracting organization. Employee perceptions of client organizational supportiveness were positively related to felt obligation and commitment to the client organization. Client felt obligation mediated the effects of client perceived organizational support (POS) on the participation dimension of citizenship behavior. Our study provides additional support for the generalizability of social exchange processes to nontraditional employment relationships. Implications for managing long‐term contracted employees are discussed. © 2006 Wiley Periodicals, Inc.
Comparison of the global gene expression profiles produced by methylparaben, n‐butylparaben and 17β‐oestradiol in MCF7 human breast cancer cells
Authors: Pugazhendhi D. , Sadler A. J. , Darbre P. D.
Published: November 2006

Since the alkyl esters of p‐hydroxybenzoic acid (parabens) can be measured intact in the human breast and possess oestrogenic properties, it has been suggested that they could contribute to an aberrant burden of oestrogen signalling in the human breast and so play a role in the rising incidence of breast cancer. However, although parabens have been shown to regulate a few single genes (reporter genes, pS2, progesterone receptor) in a manner similar to that of 17β‐oestradiol, the question remains as to the full extent of the similarity in the overall gene profile induced in response to parabens compared with 17β‐oestradiol. The GE‐Amersham CodeLink 20 K human expression microarray system was used to profile the expression of 19881 genes in MCF7 human breast cancer cells following a 7‐day exposure to 5 × 10−4 m methylparaben, 10−5 m n‐butylparaben and 10−8 m 17β‐oestradiol. At these concentrations, the parabens gave growth responses in MCF7 cells of similar magnitude to 17β‐oestradiol. The study identified genes which are upregulated or downregulated to a similar extent by methylparaben, n‐butylparaben and 17β‐oestradiol. However, the majority of genes were not regulated in the same way by all three treatments. Some genes responded differently to parabens from 17β‐oestradiol, and furthermore, differences in expression of some genes could be detected even between the two individual parabens. Therefore, although parabens possess oestrogenic properties, their mimicry in terms of global gene expression patterns is not perfect and differences in gene expression profiles could result in consequences to the cells that are not identical to those following exposure to 17β‐oestradiol. Copyright © 2006 John Wiley & Sons, Ltd.
Boys will be boys: a pre‐line‐up gameplay has beneficial effects on boys' but not girls' identification performance
Authors: Rassin Eric , Van Der Sleen Jannie , Van Amelsvoort Adri G. , Buttinger Eveline
Published: November 2006

Fifty children, aged between 4 and 7 years, underwent a sequential photo line‐up procedure in order to identify a man they had met the previous day. Half of the participants engaged in a pre‐procedure gameplay with the female interviewer. It was hypothesised that the game would stimulate rapport building and would ultimately result in an increased performance during the line‐up procedure. The beneficial effect was indeed observed, but only for the male participants. This finding suggests that gameplay may be a fruitful strategy to decrease child witness discomfort and to increase participation. Copyright © 2006 John Wiley & Sons, Ltd.
Vibrational spectra of clioquinol and its Cu(II) complex
Authors: Wagner Claudia C. , Calvo Selene , Torre María H. , Baran Enrique J.
Published: November 2006

The infrared and Raman spectra of 5‐chloro‐7‐iodo‐8‐hydroxyquinoline (clioquinol, CQ) and that of its Cu(II) complex of stoichiometry [Cu(CQ)2] were recorded and briefly discussed. Some comparisons were made with related complexes. The interest of the investigated systems in relation to Alzheimer's disease is briefly commented. Copyright © 2006 John Wiley & Sons, Ltd.
A comparative study of the hypoplasticity and the fabric‐dependent dilatant double shearing models for granular materials
Authors: Zhu Huaning , Mehrabadi Morteza M. , Massoudi Mehrdad
Published: November 2006

In this paper, we consider the mechanical response of granular materials and compare the predictions of a hypoplastic model with that of a recently developed dilatant double shearing model which includes the effects of fabric. We implement the constitutive relations of the dilatant double shearing model and the hypoplastic model in the finite element program ABACUS/Explicit and compare their predictions in the triaxial compression and cyclic shear loading tests. Although the origins and the constitutive relations of the double shearing model and the hypoplastic model are quite different, we find that both models are capable of capturing typical behaviours of granular materials. This is significant because while hypoplasticity is phenomenological in nature, the double shearing model is based on a kinematic hypothesis and microstructural considerations, and can easily be calibrated through standard tests. Copyright © 2006 John Wiley & Sons, Ltd.
Accelerating the convergence of coupled geomechanical‐reservoir simulations
Authors: Jeannin L. , Mainguy M. , Masson R. , Vidal‐Gilbert S.
Published: November 2006

The pressure variations during the production of petroleum reservoir induce stress changes in and around the reservoir. Such changes of the stress state can induce marked deformation of geological structures for stress sensitive reservoirs as chalk or unconsolidated sand reservoirs. The compaction of those reservoirs during depletion affects the pressure field and so the reservoir productivity. Therefore, the evaluation of the geomechanical effects requires to solve in a coupling way the geomechanical problem and the reservoir multiphase fluid flow problem. In this paper, we formulate the coupled geomechanical‐reservoir problem as a non‐linear fixed point problem and improve the resolution of the coupling problem by comparing in terms of robustness and convergence different algorithms. We study two accelerated algorithms which are much more robust and faster than the conventional staggered algorithm and we conclude that they should be used for the iterative resolution of coupled reservoir‐geomechanical problem. Copyright © 2006 John Wiley & Sons, Ltd.
Predicting implantation with a neuromodulator using two different test stimulation techniques: A prospective randomized study in urge incontinent women
Authors: Borawski Kristy M. , Foster Raymond T. , Webster George D. , Amundsen Cindy L.
Published: November 2006

Aims

The purpose of this study was to determine whether a percutaneous needle electrode (PNE) technique or a surgical first stage lead placement (FSLP) better predicted whether a patient would progress to implantation of a pulse generator (IPG) in older urge incontinent women.

Methods

Thirty subjects ≥55 years with refractory urge incontinence who had been selected to undergo a test stimulation procedure were randomized to either PNE or FSLP. Thirteen underwent PNE placement and seventeen underwent FSLP placement. If during the test stimulation period subjects had greater than 50% improvement in their incontinence parameters they qualified for permanent lead and/or IPG implantation of the Interstim® device.

Results

Twenty‐one subjects (70%) responded to the test stimulation and underwent implantation, 15/17 (88%) in the FSLP group and 6/13 (46%) in the PNE group. Subjects who were randomized to the FSLP group were significantly more likely to proceed to implantation of the IPG (P = 0.02) than those in the PNE group. There was no significant difference in demographics, pre‐test stimulation incontinence parameters or post‐stimulation visual analog pain scores between the randomized groups or between test stimulation responders and non‐responders. When comparing FSLP and PNE responders, there was no significant difference in the percent improvement in 24‐hr pad weight, daily pad usage, or daily incontinence.

Conclusion

FSLP better predicted progression to implantation of the IPG than a test stimulation with a PNE in an older urge incontinent cohort. Neurourol. Urodynam. © 2006 Wiley‐Liss, Inc.
In vivo analysis of the post‐natal development of normal mouse brain by DTI
Authors: Larvaron Pierre , Boespflug‐Tanguy Odile , Renou Jean‐Pierre , Bonny Jean‐Marie
Published: November 2006

The water diffusion characteristics of wild‐type mouse brains have been studied in vivo by DTI to follow developmental changes. Here, axial (λ//) and radial (λ⟂) diffusivities and fractional anisotropy were measured from the fifth day of life (P5) and at three other post‐natal ages (P12, P19 and P54). Magnetic resonance images were collected from a single sagittal slice in the middle of the two hemispheres; ROI were chosen in nine different structures of both grey and white matter. Fractional anisotropy (FA) from P5 onwards distinguished structures of both white and grey matter, even though myelination had yet to occur. Between P5 and P54, a significant increase in FA was observed in the genu of the corpus callosum due to a significant decrease in λ⟂ whereas λ// remained stable. Many other significant variations of λ// and λ⟂ were measured in different structures. They were substantially correlated with axon and myelin maturation which are responsible for the main evolutions of the brain during its post‐natal development. These quantitative data show that in vivo characterization of the anatomy and microstructure of the normal mouse brain during development is possible. The normative data will greatly improve the characterization of abnormal development in the transgenic mouse brain. Copyright © 2006 John Wiley & Sons, Ltd.
Pharmacokinetic evaluation of darbepoetin alfa for the treatment of pediatric patients with chemotherapy‐induced anemia
Authors: Blumer Jeffrey , Berg Stacey , Adamson Peter C. , Loew Thomas , Rossi Greg , Hastings Caroline
Published: November 2006

Background

Cancer patients undergoing chemotherapy often develop anemia, which can increase the risk for transfusions and fatigue. The recombinant erythropoiesis‐stimulating agent darbepoetin alfa can effectively treat chemotherapy‐induced anemia (CIA) in adults, but limited data are available regarding its use in pediatric cancer patients. The goals of this phase 1, open‐label, uncontrolled study were to assess the pharmacokinetic profile and safety of darbepoetin alfa in pediatric patients with CIA.

Procedure

Pediatric patients with nonmyeloid malignancies and CIA received up to six doses of darbepoetin alfa 2.25 mcg/kg subcutaneously. After the first dose, the pharmacokinetic properties of darbepoetin alfa were assessed during a 14‐day sampling period. All subsequent doses were given weekly with predose blood samples collected before study drug administration.

Results

After a single dose of darbepoetin alfa, the mean (SD) peak serum concentration was 10.5 (3) ng/ml, and the median time to peak concentration was 71.4 hr. Darbepoetin alfa exhibited a mean (SD) terminal half‐life of 49.4 (32) hr. Upon repeated weekly administration, no evidence of darbepoetin alfa accumulation was observed though there was high intra‐ and inter‐individual variability. In addition, darbepoetin alfa was well tolerated; some study patients experienced increases in hemoglobin.

Conclusions

The pharmacokinetic profile of darbepoetin alfa indicated that it was slowly absorbed and exhibited a long terminal half‐life in these pediatric study patients with CIA. Pediatr Blood Cancer 2007;49:687–693. © 2006 Wiley‐Liss, Inc.
Host–guest interactions in cyclodextrin inclusion complexes with solvatochromic dyes
Authors: Tirapegui Cristian , Jara Francisco , Guerrero Juan , Rezende Marcos Caroli
Published: November 2006

Host–guest interactions of α‐, β‐, and γ‐cyclodextrin with three solvatochromic dyes derived from barbituric and Meldrum's acids, 5‐(4‐N,N‐dimethylaminobenzylidene)‐1,3‐dimethyl‐2,4,6(1H,3H,5H)‐ pyrimidinetrione (1), 5‐[bis(4‐N,N‐dimethylaminophenyl)methylene]‐1,3‐dimethyl‐2,4,6(1H,3H,5H)‐pyrimidinetrione (2), and 5‐(4‐N,N‐dimethylaminobenzylidene)‐2,2‐dimethyl‐1,3‐dioxane‐4,6‐dione (3), were studied by UV–visible and 1H‐NMR spectroscopic methods, and the obtained results compared with molecular dynamics simulations employing the linear interaction energy (LIE) protocol. Copyright © 2006 John Wiley & Sons, Ltd.
Controlled charging of the same single quantum dot from +6e to ‐8e: emission, shell filling and configuration interactions
Authors: Ediger M. , Karrai K. , Badolato A. , Petroff P. M. , Warburton R. J.
Published: November 2006

We present photoluminescence spectra from single InAs/GaAs quantum dots embedded in a Schottky diode heterostructure. The pronounced Coulomb blockade can be exploited to change the exciton charge in discrete steps from +6e to ‐8e via an applied gate voltage. The results demonstrate a number of effects. The spectra of highly negatively charged excitons are dominated by configuration interactions in the final state, a viewpoint supported by few‐electron calculations based on a harmonic oscillator potential. The positively charged excitons on the other hand show a very different behavior that can only be explained by taking strong spin‐orbit coupling for the holes into account. Particularly, a hole charging sequence is revealed that defies Hund's rule as well as the Aufbau principle. Finally, photoluminescence from excited states offers direct access to the hole quantization energy. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Narrowing of ground energy level distribution in an array of InAs/AlAs QDs by post grown annealing
Authors: Shamirzaev T. S. , Kalagin A. K. , Toropov A. I. , Gutakovskii A. K. , Zhuravlev K. S.
Published: November 2006

The effect of a post growth annealing on the structure and photoluminescence (PL) of InAs/AlAs quantum dots has been studied. The annealing at temperatures below 650 ºC does not effect the PL spectrum, while a blue shift as large as 400 meV and a significant narrowing of the QD PL band are observed at annealing temperatures in the range 650–950 ºC. Transmission electron microscopy demonstrates that the changes in the PL spectrum are accompanied by an increase in the average QD size and its dispersion. The blue shift and narrowing are explained by a shift of the QD energy levels towards the level of a shallow quantum well as a result of interdiffusion. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical fine structure of II‐VI and III‐V nanocrystals: the role of d orbitals in a tight‐binding approach
Authors: Díaz J. G. , Bryant G. W. , Jaskólski W.
Published: November 2006

The electronic structure of GaAs and CdSe nanocrystals is studied by using a nearest neighbor tight‐binding model extended to include d orbitals. Our results show that the inclusion of d orbitals in a minimal basis set is necessary for a proper description of the lowest electron states, especially in the strong confinement regime. We have checked that simpler sp 3s * models yield an incorrect description of electron states made from bulk band‐states away from the Brillouin zone center. For GaAs nanocrystals with sizes below 2.5 nm, the d model predicts that the ground electron state is primarily built of L‐point band‐states, giving the nanocrystal an indirect‐gap character. The sp 3d 5 model also explains successfully the evolution of the absorption peaks in CdSe nanocrystals with confinement. We provide an interpretation of the fine band‐edge structure based on an orbital‐forbidden dark exciton mechanism, which is in agreement, for the first time, with both the resonant and non‐resonant experimental Stokes shifts. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Enhanced shot noise in tunneling through coupled self‐assembled InAs quantum dots
Authors: Barthold P. , Hohls F. , Maire N. , Pierz K. , Haug R. J.
Published: November 2006

We present measurements of the shot noise of vertically coupled self‐assembled InAs quantum dots (QDs) and find a surprising enhancement with a distinct double‐peak structure.

1By applying an external bias voltage we observe pronounced peaks in the dc current–voltage characteristics that correspond to electron transport through a stack of vertically coupled QDs. At these peaks we find enhanced shot noise in contrast to suppressed shot noise at a single layer of QDs.

To characterize the measured shot noise S the so‐called Fano factor α is introduced. At both sides of the current peak the Fano factor α rises to values up to 1.4, whereas the noise is reduced on top of the peak (α < 1). We discuss qualitative agreement with a theoretical model which predict such a super‐Poissonian shot noise. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Evidence for excitonic polarons in InAs/GaAs quantum dots
Authors: Preisler V. , Grange T. , Ferreira R. , de Vaulchier L. A. , Guldner Y. , Teran F. J. , Potemski M. , Lemaître A.
Published: November 2006

We investigate the interband transitions in several ensembles of self‐assembled InAs/GaAs quantum dots by using photoluminescence excitation spectroscopy under strong magnetic field. Well defined resonances are observed in the spectra. Astrong anticrossing between two transitions is observed in all samples, which cannot be accounted for by a purely excitonic model. The coupling between the mixed exciton‐LO phonon states is calculated using the Fröhlich Hamiltonian. The excitonic polaron energies as well as the oscillator strengths of the interband transitions are determined. An anticrossing is predicted when two exciton‐LO phonon states have close enough energies with phonon occupations which differ by one. Agood agreement is found between the calculations and the experimental data evidencing the existence of excitonic polarons. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ground state transition energies of electron and hole in biased InxGa1–xN/GaN quantum dots
Authors: Turki‐BenAli Y. , Bennaceur R.
Published: November 2006

We are interested in our study of the III‐V nitrides to the InxGa1–xN/GaN quantum dots, where x = 17.5% denotes the indium concentration. The adopted model to describe these III‐V nitride quantum dots is that of InxGa1–xN truncated cones of radius rc lying on wetting layer, both buried into GaN matrix. This model is consistent with recent experimental works. We examine the internal electric field and radius rc of the quantum dots effects on the ground state transition energies of the electron and the hole. Our results are in sound agreement with recent experimental data. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A semiconducting nanotube quantumdot: effect of the form of the confinement potential
Authors: Roy Mervyn , Maksym P. A.
Published: November 2006

The states of a few (2‐6) interacting electrons in a semiconducting carbon nanotube quantum dot are investigated for two extremes of the quantum dot confinement potential: harmonic and hard wall. The interacting electron states are calculated by exact diagonalisation of a single band, effective mass Hamiltonian, then the quantum dot addition energies and few particle densities are compared for the two types of confinement. By changing the harmonic confinement strength the system can be driven between the strongly and weakly correlated regimes, whereas for hard wall confinement the electrons are almost always strongly correlated. With hard wall or weak harmonic confinement the electrons localise and form Wigner crystal‐like states. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrospray ionization mass spectrometry fingerprinting of perfumes: rapid classification and counterfeit detection
Authors: Marques Lygia de Azevedo , Catharino Rodrigo Ramos , Bruns Roy E. , Eberlin Marcos N.
Published: November 2006

A fast procedure to classify perfumes and identify counterfeit samples is described. Dilution of a few µL of the sample in a 1:1 methanol/water solution is followed by detection of its major polar components via direct infusion electrospray ionization mass spectrometry (ESI‐MS) in the positive ion mode. As proof‐of‐principle cases, three famous brands of perfumes were used. The ESI(+)‐MS fingerprints of authentic samples were very characteristic, showing distinctive sets of polar markers for each sample. Principal component analysis (PCA) placed samples of the three perfume brands in well‐defined groups. Counterfeit samples were also clearly detected owing to contrasting ESI‐MS fingerprints, with PCA placing these samples far away from the authentic samples. Copyright © 2006 John Wiley & Sons, Ltd.
‘On‐the‐fly’ hydrogen/deuterium exchange liquid chromatography/mass spectrometry using a dual‐sprayer atmospheric pressure ionisation source
Authors: Wolff Jean‐Claude , Laures Alice M.‐F.
Published: November 2006

In‐source ‘on‐the‐fly’ hydrogen/deuterium (H/D) exchange liquid chromatography mass spectrometry (LC/MS) has been investigated. The work was performed using a dual‐sprayer source. The analyte was introduced through an electrospray ionisation sprayer and D2O was introduced through an atmospheric pressure chemical ionisation sprayer. To achieve H/D exchange sufficient to determine the number of exchangeable H atoms of a compound, a saturated ‘steady‐state’ D2O atmosphere had to be created in the ion source by having a 2:1 or higher D2O‐to‐analyte flow rate ratio. Under these conditions H/D exchange levels of 32–90% were achieved. In most cases the H/D exchange was sufficient to measure the number of exchangeable H atoms in some antiulcerative and anthelmintic pharmaceuticals. The concept of in‐source ‘on‐the‐fly’ H/D exchange by introducing the deuterating agent via a second sprayer has been shown. It allows the integrity of the chromatographic separation to be kept, since the H/D exchange takes place post‐separation. Copyright © 2006 John Wiley & Sons, Ltd.
The scent of urine spots of male mice, Mus musculus: changes in chemical composition over time
Authors: Cavaggioni Andrea , Mucignat‐Caretta Carla , Redaelli Marco , Zagotto Giuseppe
Published: November 2006

A dominant male mouse scent‐marks his territory very frequently by emitting small urinary spots. The urine spots release in the air a variety of odorants that transmit different information to other mice, especially those concerning the time of deposition. To investigate this effect, small spots of urine of a dominant male mouse were left to freely release the odorants in the air for time intervals ranging from 0 min to 24 h prior to sampling. Thereupon, the odorants remaining in the spot were sampled at diffusion equilibrium (45°C) in a small vial by means of headspace solid‐phase microextraction followed by gas chromatography coupled to flame ionisation detection and mass spectrometry. Thirteen odorants were consistently found. Nine odorants were identified and four were matched. The rate of release of each odorant was characteristic and was described using principal component analysis. A first principal component was based on nine early odorants that showed a decreasing release over time. The odorants were 2,4‐dehydro‐exo‐brevicomin, an unknown with 78% matching to 4‐acetonilcycloheptanone, linalool, 2,4‐dimethyl‐phenol, 4‐ethylphenol, indole, 2‐butyl‐1‐octanol, an unknown with 83% matching to 2‐ethyl‐1‐decanol, and 2,4‐bis‐(1,1‐dimethylethyl)phenol. A second principal component, based on two unknowns with 73% matching to yohimban‐17‐one and 71% matching to the 2‐methyl‐3‐hydroxy‐2,4,4‐trimethyl ester of propanoic acid, had an irregular release after deposition. A third principal component of late odorants, based on 2‐sec‐butyl‐4,5‐dihydrothiazole and 6,10‐dimethyl‐5,9‐undecaden‐2‐one, had a peak of release at about 22 min. In conclusion, the release of the odorants in the headspace of a urine spot may code and transmit information on the deposition time. Copyright © 2006 John Wiley & Sons, Ltd.
Liquid chromatography/tandem mass spectrometric study and analysis of xanthone and secoiridoid glycoside composition of Swertia chirata, a potent antidiabetic
Authors: Suryawanshi Satyendra , Mehrotra Nitin , Asthana R. K. , Gupta Ram C.
Published: November 2006

Swertia chirata is a bitter plant, used in the Indian system of medicine (Ayurveda) for various human ailments. The bioactive constituents include the xanthone and secoiridoid glycosides consisting of mangiferin, amarogentin, amaroswerin, sweroside and swertiamarin. Methanolic extracts of S. chirata possess constituents with antidiabetic activities, which was investigated by high‐performance liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI‐MS/MS). Preliminary HPLC analyses were performed on a reversed‐phase C18 column using gradient elution. In the LC/ESI‐MS spectra, predominant [M+H]+ and [M+Na]+ ions were observed in positive ion mode and provided molecular mass information. The five components of S. chirata were structurally correlated and confirmed based on the fragmentation characteristics and information available in the literature. The fragmentation behavior of [M+H]+/[M+Na]+ ions of these components were deduced from the collision‐induced dissociation (CID) spectra obtained from the selective on‐column information‐dependant acquisition (IDA) approach. Xanthone‐C‐glycoside showed characteristic fragment ions due to fragmentation in the C‐glycosidic unit while iridoid‐O‐glycosides showed characteristic fragment ions due to cleavage in the glycoside linkage and retro‐Diels‐Alder (RDA) cleavage within an iridoid aglycone. Furthermore, on the basis of this information, an analytical assay was developed and validated to determine relative concentrations of mangiferin, amarogentin, amaroswerin, sweroside and swertiamarin. The detection was carried out using multiple reaction monitoring (MRM) in positive ionization mode with a total analysis time of 3.5 min. The method was successfully applied to standardize four different batches of herbal preparation on the basis of relative concentration of five bioactive components. Copyright © 2006 John Wiley & Sons, Ltd.
Developing multiple high‐throughput GLP methods for an investigational drug candidate in various matrices within a 96‐well plate
Authors: Zhang Jun , Kim Elaine J. , Ji Qin C. , El‐Shourbagy Tawakol A.
Published: November 2006

In early pharmaceutical product development, an investigational drug candidate is typically dosed to various species for toxicological and pharmacokinetic studies. Most of these studies require multiple analytical methods that have to be validated with good laboratory practice (GLP) prior to the application in regulated studies. Usually, these analytical methods are developed in either a serial or parallel approach. For either approach, the development of multiple analytical methods takes tremendous work from scientists and instruments, and thus is not cost‐effective. In this respect, a new strategy has been developed for simultaneous GLP method development using liquid chromatographic separation and tandem mass spectrometric detection. This high‐throughput approach allows system suitability, carryover, calibration curve, accuracy, precision, matrix effect and selectivity to be evaluated in one 96‐well plate. The strategy has been successfully implemented for multiple investigational drug candidates at Abbott Laboratories. The methods developed with this strategy are accurate, precise, selective, robust and matrix‐independent. As an example, ABT‐279 was used to demonstrate the feasibility of this strategy. Copyright © 2006 John Wiley & Sons, Ltd.