bluuebunny/crossref_metadata_2025 huggingface dataset:
Depression in veterans with Parkinson's disease: frequency, co‐morbidity, and healthcare utilization
Authors: Chen Peijun , Kales Helen C. , Weintraub Daniel , Blow Frederic C. , Jiang Lan , Ignacio Rosalinda V. , Mellow Alan M.
Published: November 2006

Objective

To determine the frequency of depression in Parkinson's disease (PD) in routine clinical care, and to examine its association with co‐morbid psychiatric and medical conditions and healthcare utilization.

Methods

Depression diagnoses and healthcare utilization data for all male veterans with PD age 55 or older seen in fiscal year 2002 (n = 41,162) were analyzed using Department of Veterans Affairs (VA) national databases. Frequencies of co‐morbid disorders and healthcare utilization were determined for depressed and non‐depressed patients; associations with depression were examined using multivariate logistic regression models.

Results

A depression diagnosis was recorded for 18.5% of PD patients, including major depression in 3.9%. Depression decreased in frequency and severity with increasing age. In multivariate logistic regression models, depressed patients had significantly greater psychiatric and medical co‐morbidity, including dementia, psychosis, stroke, congestive heart failure, diabetes, and chronic obstructive pulmonary disease than non‐depressed patients (all p < 0.01). Depressed PD patients were also significantly more likely to have medical (OR = 1.34, 95% CI = 1.25–1.44) and psychiatric hospitalizations (OR = 2.14, 95% CI = 1.83–2.51), and had more outpatient visits (p < 0.01), than non‐depressed PD patients in adjusted models.

Conclusion

Depression in PD in non‐tertiary care settings may not be as common or as severe as that seen in specialty care, though these findings also may reflect under‐recognition or diagnostic imprecision. The occurrence of depression in PD is associated with greater psychiatric and medical co‐morbidity, and greater healthcare utilization. These findings suggest that screening for depression in PD is important and should be embedded in a comprehensive psychiatric, neuropsychological, and medical evaluation. Copyright © 2006 John Wiley & Sons, Ltd.
Subtle imitation behaviour in convenience samples of normal, demented, and currently depressed elderly subjects
Authors: von Gunten Armin , Duc René
Published: November 2006

Background

The clinical significance of imitation behaviour (IB) is unclear. The aim of this study was to investigate the prevalence of subtle naïve and obstinate IB in convenience samples of normal elderly, demented, and depressed subjects.

Method

Subtle IB was assessed using a protocol constructed ad hoc in 146 patients, consecutively referred to a memory clinic having received an ICD‐10 diagnosis of either dementia or depression, and in 241 healthy subjects. The prevalence of IB in the three groups was determined and the association with possible demographic, cognitive, and non‐cognitive variables analysed.

Results

Subtle naïve IB was frequent in the elderly with dementia, intermediate in the depressed, and rare in the normal elderly except that the latter frequently stretched out their arms. Obstinate IB never occurred in the normal elderly. IB was predicted by none of the variables used.

Limitations

The groups included were convenience samples with the depressed being a small group precluding further distinction of depressive subtypes.

Conclusion

Although naïve IB is a frequent clinical feature in the demented, it also accompanies depressive disorders in the elderly. It can be observed as context‐specific IB in the normal elderly. Obstinate IB does not occur in the normal elderly. Copyright © 2006 John Wiley & Sons, Ltd.
Behavioural disturbance triggers recognition of dementia by family informants
Authors: Eustace A. , Bruce I. , Coen R. , Cunningham C. , Walsh C. , Walsh J.B. , Coakley D. , Lawlor B.A.
Published: November 2006

Objective

To determine the frequency of unrecognised dementia in a group of community dwelling elderly, and to identify factors associated with dementia recognition by informants.

Sample selection

People over 65 years with an AGECAT case or subcase organic diagnosis or an MMSE ≤ 23 were identified from a database of community dwelling elderly. A psychiatrist to confirm the diagnosis of dementia according to ICD‐10 criteria interviewed these individuals.

Study participants

Sixty‐two community dwelling elderly meeting ICD‐10 criteria for dementia whom had reliable informants.

Methods

Prior to the start of the interview the informant was questioned about whether they felt the patient had memory difficulties and if so whether they had a medical evaluation for their memory problems. A psychiatrist then interviewed the patient and informant to establish whether that patient met ICD‐10 criteria for dementia. Basic sociodemographic details were collected and the following assessments were carried out: the Blessed Dementia Rating Scale, the Clinical Dementia Rating Scale, the Behave‐AD and the Baumgarten Behavioural Disturbance Scale.

Analysis

Univariate and step‐wise forward logistic regression analysis were used to examine the factors associated with recognition of memory difficulties.

Results

Twenty‐nine percent of family informants of people with dementia failed to recognise a problem with their relatives'memory. Where memory difficulties were recognised only 39% of this group received a medical evaluation. Using univariate analysis recognition of memory difficulties by family informants was associated higher levels of behaviour disturbance ( p = < 0.0011), greater functional impairment ( p = 0.0039), with increasing cognitive impairment ( p = 0.013). Using a logistic regression model, to test the independence of these variables, increasing behavioural disturbance (p = 0.0001) was associated with recognition of dementia by family informants.

Conclusions

Recognition of memory problems by family members is associated with increasing behavioural disturbance. Even with recognition of dementia, families often fail to seek medical attention. Education of the lay public on the early signs and symptoms of dementia must be a key first step in improving recognition of dementia in the community dwelling elderly. Copyright © 2006 John Wiley & Sons, Ltd.
Reaching the population with dementia drugs: what are the challenges?
Authors: Matthews Fiona E , McKeith Ian , Bond John , Brayne Carol
Published: November 2006

Background

Systematic evidence became available in the late 1990s on efficacy of cholinesterase inhibitors (CHEIs) for patients with mild to moderate Alzheimer's disease (AD) and they began to be used sporadically. Since January 2001 UK based guidelines indicated that one of three cholinesterase inhibitors (CHEIs) could be prescribed for these patients. Since then the cost of prescription in England and Wales has risen. There has been little investigation of uptake at the population level.

Objective

To estimate the population uptake of CHEIs in a population based study of dementia spanning this period.

Design

Using data from a 10‐year follow up and a later 12 year interview of the Medical Research Council Cognitive Function and Ageing Study (MRC CFAS), a UK population based longitudinal cohort study of people originally aged 65 years and above, we investigated who was taking CHEIs during the period 2001–2004. We sought information from respondents taking part in the study what medication they were taking on a regular basis.

Results

Only 12, of the 219 individuals who received a study diagnosis of dementia were prescribed CHEIs [5%, 95% Confidence Intervals (CI) 3%–9%]) in 2001/2003 and none of the 28 individuals with a study diagnosis of dementia (0%, 95% CI 0–18%) in 2004 were prescribed CHEIs. Uptake was biased towards individuals with more education and higher social class.

Conclusions

These data suggest that any impact on AD progression at the population level will be negligible as prescription of CHEIs and uptake in the age group at highest risk is so limited. There is little evidence that this has changed over time. Copyright © 2006 John Wiley & Sons, Ltd.
5α‐Reductase type 2 gene variant associations with prostate cancer risk, circulating hormone levels and androgenetic alopecia
Authors: Hayes Vanessa M. , Severi Gianluca , Padilla Emma J.D. , Morris Howard A. , Tilley Wayne D. , Southey Melissa C. , English Dallas R. , Sutherland Robert L. , Hopper John L. , Boyle Peter , Giles Graham G.
Published: November 2006

Controversy exists over the significance of associations between theSRD5A2(5α‐reductase type 2) polymorphisms, A49T and V89L, and risk of prostate cancer. These potentially functional polymorphisms may alter life‐long exposure to androgens with subsequent effects on male health and aging. The aim of this study was to examine the association of these variants with prostate cancer risk, plasma hormone levels and androgenetic alopecia. Subjects include 827 cases and 736 controls from an Australian population‐based case–control study of prostate cancer. Information on prostate cancer risk factors and patterns of balding were collected. Plasma levels of testosterone, 3α‐diol glucuronide (3α‐diolG), dehydroepiandrosterone sulfate, androstenedione, sex hormone‐binding globulin and estradiol were measured for controls. No associations with the V89L polymorphism were found. Carriers of the rarer A49T A allele were at a 60% higher risk of prostate cancer (OR = 1.60; 95% CI 1.09–2.36;p= 0.02) and 50% lower risk of vertex and frontal balding (p= 0.03) compared with men homozygous for the more common G allele. Although we found little evidence of association between this variant and plasma levels of 5 measured androgens, circulating 3α‐diolG levels were 34% lower in A49T A allele carriers (p< 0.0001). Our study provides evidence that theSRD5A2A49T A variant is associated with an increased risk of prostate cancer, lower levels of circulating 3α‐diolG and decreased risk of baldness. These findings raise important questions with respect to previous assumptions concerning hormonal influences on prostate cancer risk in ageing males. © 2006 Wiley‐Liss, Inc.
The geometry of sets of orthogonal frequency hypercubes
Authors: Mavron V. C. , McDonough T. P. , Mullen Gary L.
Published: November 2006

We extend the notion of a framed net, introduced by D. Jungnickel, V. C. Mavron, and T. P. McDonough, J Combinatorial Theory A, 96 (2001), 376–387, to that of a d‐framed net of type ℓ, where d ≥ 2 and 1 ≤ ℓ ≤ d‐1, and we establish a correspondence between d‐framed nets of type ℓ and sets of mutually orthogonal frequency hypercubes of dimension d. We provide a new proof of the maximal size of a set of mutually orthogonal frequency hypercubes of type ℓ and dimension d, originally established by C. F. Laywine, G. L. Mullen, and G. Whittle, Monatsh Math 119 (1995), 223–238, and we obtain a geometric characterization of the framed net when this bound is satisfied as a PBIBD based on a d‐class association Hamming scheme H(d,n). © 2006 Wiley Periodicals, Inc. J Combin Designs 15: 449–459, 2007
Mass spectrometric characterization of low‐molecular‐mass color pI markers and their use for direct determination of pI value of proteins
Authors: Mazanec Karel , Šlais Karel , Chmelík Josef
Published: November 2006

The use of low‐molecular‐mass color pI markers for the determination of pI values of proteins in gel isoelectric focusing (IEF) in combination with mass spectrometry is described. Different types of substituted phenols of known pI values within the mass range 250–400 were used here as pI markers. The pure, synthesized pI markers were studied by MALDI‐TOF/TOF MS. Fragmentation studies of the pI markers were also performed. Only stable and well‐characterized pI markers were used in this work. The selected pI markers were mixed with proteins, deposited on a gel and separated in a pH gradient.

Color pI markers enable supervision of progress of the focusing process and also estimation of the position of the invisible focused bands. The separated bands of the pI markers (containing separated proteins) were excised, and the pI markers were eluted from each gel piece by water/ethanol and identified by MALDI‐TOF/TOF MS.

From the washed gel pieces the remaining carrier ampholytes were then washed out and proteins were in‐gel digested with trypsin. The obtained peptides were measured by MALDI‐TOF/TOF MS and the proteins identified via a protein database search. This procedure allows avoiding time‐consuming protein staining and destaining procedures, which shortens the analysis time roughly by half. For comparison, IEF gels were stained with Coomassie Brilliant Blue R 250 and proteins in the gel bands were identified according to the standard proteomic protocol. This work has confirmed that our approach can give information about the correct pI values of particular proteins and shorten significantly the time of analysis. Copyright © 2006 John Wiley & Sons, Ltd.
A study of the glutathione metaboloma peptides by energy‐resolved mass spectrometry as a tool to investigate into the interference of toxic heavy metals with their metabolic processes
Authors: Rubino Federico Maria , Pitton Marco , Brambilla Gabri , Colombi Antonio
Published: November 2006

To better understand the fragmentation processes of the metal–biothiol conjugates and their possible significance in biological terms, an energy‐resolved mass spectrometric study of the glutathione conjugates of heavy metals, of several thiols and disulfides of the glutathione metaboloma has been carried out. The main fragmentation process of γ‐glutamyl compounds, whether in the thiol, disulfide, thioether or metal‐bis‐thiolate form, is the loss of the γ‐glutamyl residue, a process which ERMS data showed to be hardly influenced by the sulfur substitution. However, loss of the γ‐glutamyl residue from themono‐S‐glutathionyl‐mercury (II) cation is a much more energetic process, possibly pointing at a strong coordination of the carboxylic group to the metal. Moreover, loss of neutral mercury from ions containing the γ‐glutamyl residue to yield a sulfenium cation was a much more energetic process than those not containing them, suggesting that the redox potential of the thiol/disulfide system plays a role in the formal reduction of the mercury dication in the gas phase. Occurrence of complementary sulfenium and protonated thiol fragments in the spectra of protonated disulfides of the glutathione metaboloma mirrors the thiol/disulfide redox process of biological importance. The intensity ratio of the fragments is proportional to the reduction potential in solution of the corresponding redox pairs. This finding has allowed the calculation of the previously unreported reduction potentials for the disulfide/thiol pair of cysteinylglycine, thereby confirming the decomposition scheme of bis‐ andmono‐S‐glutathionyl‐mercury (II) ions. Finally, on the sole basis of the mass spectrometric fragmentation of the glutathione–mercury conjugates, and supported by independent literature evidence, an unprecedented mechanism for mercury ion‐induced cellular oxidative stress could be proposed, based on the depletion of the glutathione pool by a catalytic mechanism acting on the metal (II)–thiol conjugates and involving as a necessary step the enzymatic removal of the glutamic acid residue to yield a mercury (II)–cysteinyl‐glycine conjugate capable of regenerating neutral mercury through the oxidation of glutathione thiols to the corresponding disulfides. Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis and Curing of Liquid‐Crystalline Epoxy Resins Containing a Biphenyl Mesogen
Authors: Liu Guodong , Gao Jungang , Song Lili , Hou Wenjun , Zhang Liucheng
Published: November 2006

Summary: Liquid crystalline epoxies with a biphenyl mesogenic group have been widely studied although it is still in contention as to whether the diglycidyl ether of DGEBP shows a thermotropic phase. DEPBP was synthesized by partial oxidation and the liquid crystalline properties were investigated. Despite their similar structures their molecular weights are quite different. DEPBP has a distinct molecular weight, while DGEBP shows a molecular weight distribution. DEPEBP was also synthesized and characterized to investigate the influence of the flexible spacer. By incorporation of a flexible ethoxy group, the monomer shows no thermotropic property even in its curing reaction with an aromatic diamine, DDM. The curing rate was decelerated and the cured network showed a Tg even lower than that of cured DGEBA/DDM. The curing kinetics of DEPBP and DEPEBP were also tentatively investigated.

Arrhenius plot of DEPBP/DDM at α = 0.15.

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Arrhenius plot of DEPBP/DDM at α = 0.15.
Cover Picture: Macromol. Chem. Phys. 23/2006
Authors: Escobar Ivirico Jorge L. , Salmerón Sánchez Manuel , Sabater i Serra Roser , Meseguer Dueñas José María , Gómez Ribelles José Luis , Monleón Pradas Manuel
Published: November 2006

Cover: The graphic shows the 3D structure of the new poly(ϵ‐caprolactone) copolymer networks able to modulate the water uptake by the controlled fraction of OH groups in the hydroxyethyl acrylate units (in green). Further details can be found in the Full Paper by J. L. Escobar Ivirico, M. Salmerón Sánchez,* R. Sabater i Serra, J. M. Meseguer Dueñas, J. L. Gómez Ribelles, M. Monleón Pradas on page 2195.
A Contribution to the Investigation of Enzyme‐Catalysed Hydrolysis of Poly(ethylene terephthalate) Oligomers
Authors: Nechwatal Axel , Blokesch Axel , Nicolai Monika , Krieg Marcus , Kolbe Axel , Wolf Monika , Gerhardt Matthias
Published: November 2006

Summary: One strategy to solve the problem of unwanted PET oligomer deposits in textile production is their enzymatic cleavage. In this work a selection of different enzymes (esterases, lipases) were tested for this purpose. The capacity to hydrolyse PET oligomers of some of the tested enzymes has been previously described in the literature. In order to imitate practical conditions both dry and precipitated PET oligomers were used. The decrease in the amount of cyclic trimer, the main component of the PET oligomers, was monitored by HPLC. After treatment with the lipase from Triticum aestivum a decrease of 80 wt.‐% was found. However, the effect of this lipase seems to have less to do with catalysing hydrolytic cleavages of ester groups than with the absorption of the oligomer on the enzyme protein.

Cyclic PET trimer (cyclo‐tris[ethyleneglycolterephthalate]).

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Cyclic PET trimer (cyclo‐tris[ethyleneglycolterephthalate]).
Gas‐Response Studies of Polyaniline Composite Film Containing Zeolite to Chemical Vapors
Authors: Ma Xingfa , Xu Huizhong , Li Guang , Wang Mang , Chen Hongzheng , Chen Song
Published: November 2006

Summary: In order to obtain new materials with synergetic or complementary behaviors, polyaniline composite was prepared by chemical oxide method using zeolite as template. A film over interdigital carbon electrodes was formed via casting approach. Gas sensitivity of the film to trimethylamine was examined at room temperature. The results indicated that, in comparison with the polyaniline film prepared by normal in situ polymerization, not only the morphology of polyaniline composite was clearly different, but also the heat stability of polyaniline film was improved significantly by adding zeolite. Gas sensitivity of the composite film to trimethylamine strongly depended on the type of zeolite added. For the system containing β‐zeolite (its specific surface area was 592 m2 · g−1, the size of the channel was 2.27 nm, mole ratio of Si/Al was 60), the gas sensitivity to trimethylamine decreased remarkably compared with that of polyaniline film and for FUYB‐zeolite (its specific surface area was 740 m3 · g−1, the size of the channel was 2.46 nm, mole ratio of Si/Al was 12), it was enhanced significantly. All these may be the results of synergetic effects or complementary behaviors between polyaniline and zeolite. This composite film showed excellent gas sensitivity and stability, rapid response to trimethylamine, and good selectivity to analogous gases while being easily recovered with high‐purity N2 to exhibit good reproducibility.

Dynamical response of polyaniline composite film containing zeolite to trimethylamine.

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Dynamical response of polyaniline composite film containing zeolite to trimethylamine.
Structure and Morphology Development in Films of mLLDPE/LDPE Blends During Blowing
Authors: Silvestre Clara , Cimmino Sossio , Raimo Maria , Duraccio Donatella , del Amo Fernandez Bernardo , Lafuente Pilar , Sanz Virginia Leal
Published: November 2006

Summary: In this work the analysis of the structure orientation, morphology, relaxation time and optical properties of blown films of mLLDPE, LDPE and their blends were performed by using WAXD, SALS, AFM, DSC and rheological and haze tests. For mLLDPE film, the crystals do not present “a”‐axis orientation along the machine direction; a distinct spherulite like superstructure is seen. The film surface is very rough. The values of bulk and surface haze are higher than LDPE and blends, whereas the relaxation time is lower. For LDPE film the (110) planes are parallel and at same time twisted with respect to the layer of the film with the “a”‐axis well oriented along the machine direction. No spherulite superstructure is observed and the surface of the film is more regular. High values of relaxation time are observed. The surface haze is the predominant contribution to the total haze. For the blend films no clear and distinct spherulite structures are observed. The orientation degree increases with composition never approaching that of LDPE. The surface is very more regular and smooth than that of the pure polymers. The haze values are below the values of pure materials. It was underlined that bulk and surface morphology and orientation degree of the crystalline planes along the machine direction dictate the optical properties of the films. Moreover both orientation and morphology are defined by the PE molecular and melt rheology characteristics, processing conditions and blend composition.

Total, bulk and surface haze of mLLDPE/LDPE blend films as a function of composition.

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Total, bulk and surface haze of mLLDPE/LDPE blend films as a function of composition.
Catalyzed Solid‐State Polyamidation
Authors: Vouyiouka Stamatina N. , Papaspyrides Constantine D. , Pfaendner Rudolf
Published: November 2006

Summary: The current study is focused on key experiments on catalyzed SSP, examining the effect of selected phosphonates on the overall process rate. Catalyst incorporation was achieved through melt blending in a single screw extruder, providing a suitable and homogenous starting material for the reaction in the solid phase. More specifically, the post‐polycondensation runs were performed in a fixed bed reactor under flowing nitrogen at 160 and 200 °C. The additives used were found to catalyze the reaction in the solid phase, resulting even in tripling the solution relative viscosity after 4 h of SSP. Differences in the catalytic performance of the added materials were observed and correlated to the catalysts properties and morphology. An indicative potential catalysis mechanism is suggested, in which reactivity enhancement through partial attachment of the phosphorus compounds on the polyamide chain is the key step. Finally, the kinetics of the process were examined based on a power‐law rate expression, which was further modified so as to relate the apparent SSP rate constant with the phosphorus concentration.

SSP rate constants as a function of catalyst content.

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SSP rate constants as a function of catalyst content.
Preparation and Properties of Vinylester Resin/Clay Nanocomposites
Authors: Ray Dipa , Sengupta Suparna , Sengupta S. P. , Mohanty Amar K. , Misra Manjusri
Published: November 2006

Summary: Vinylester resin matrix composites were fabricated with 1, 3, 5 and 10 wt.‐% loadings of organoclay. The composite samples were subjected to various characterization techniques like X‐ray diffraction, flexural testing, dynamic mechanical analysis, thermogravimetric analysis, and scanning electron microscopy. The clay samples as well as the clay–resin composites were investigated by X‐ray diffraction. From the shift in the peak positions and the change in d‐spacing values, it was evident that there was intercalation in the 10 wt.‐% composites, whereas exfoliation occurred in the 1, 3, and 5 wt.‐% composites. The flexural strength and the breaking energy of all the composites were decreased compared with the unfilled resin, but there was an increase in flexural modulus value by 13%. From the dynamic mechanical analysis of the 3 and the 5 wt.‐% composites, it was observed that the loss modulus value was higher in the 3 wt.‐% composites, but the glass transition temperature was slightly higher in the 5 wt.‐% composites. Thermal degradation behavior was also improved in the 5 wt.‐% composites compared with the 3 wt.‐% composites.

Fracture surface of 3 wt.‐% clay filled vinylester resin matrix composite in different magnifications.

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Fracture surface of 3 wt.‐% clay filled vinylester resin matrix composite in different magnifications.
Study on Superabsorbent Composite, 14
Authors: Zhang Junping , Chen Hao , Li Ping , Wang Aiqin
Published: November 2006

Summary: Organo‐attapulgite (organo‐APT) was prepared by modifying APT using four quaternary ammonium salts with various lengths of the alkyl group, including (octyl)trimethylammonium bromide (OTMABr) and (stearyl)trimethylammonium chloride (STMACl), etc. A series of composite hydrogels, poly(acrylic acid)/organo‐APT, from acrylic acid (AA), and organo‐APT was prepared by aqueous polymerization, using N,N′‐methylenebisacrylamide (MBA) as a crosslinker and ammonium persulfate (APS) as an initiator. The organification and organification degree of APT as well as the corresponding composites were characterized by FTIR, TGA, and XRD. The effects of the length of the alkyl group for different quaternary ammonium salts, organification degree of APT, and organo‐APT content on water absorbency and swelling behaviors in various electrolyte solutions were investigated in this study. Equilibrium water absorbency strongly depends on chain length of the alkyl group of quaternary ammonium salts, organification degree of APT as well as organo‐APT content. Longer alkyl group, higher organification degree, and proper organo‐APT content are of benefit for the improvement of equilibrium water absorbency. Equilibrium water absorbency in distilled water for PAA/APT was enhanced from 350.1 to 562.1 g · g−1 after 10 wt.‐% organo‐APT, modified with STMACl for the highest degree, was introduced. The kind of cation is the key factor influencing equilibrium water absorbency of these composite hydrogels in electrolyte solutions. Organification of APT could enhance responsiveness of the corresponding composite hydrogel to electrolyte solutions.

Schematic structure of PAA/organo‐APT composite in a dry state (left) and in a swollen state (right).

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Schematic structure of PAA/organo‐APT composite in a dry state (left) and in a swollen state (right).
Effect of Carbon Nanofiber Functionalization on the Dispersion and Physical and Mechanical Properties of Polystyrene Nanocomposites
Authors: Morales‐Teyssier Octavio , Sánchez‐Valdes Saul , Ramos‐de Valle Luis Francisco
Published: November 2006

Summary: The effect of peroxide functionalization of carbon nanofibers (CNF) on the physical and mechanical properties of polystyrene (PS)–CNF nanocomposites prepared via melt mixing was studied. The CNF functionalization was evidenced by Raman spectroscopy, comparing the ratio of peaks at 1 371 and at 1 590 cm−1 (peaks related to the disordered sp3‐hybridized carbon atom and to the graphitic structure of the sp2‐hybridized carbon atoms, respectively). The variation of the storage (E′) and tensile modulus (E) of the PS–CNF composites as a function of the untreated and peroxide treated CNF concentration were evaluated. Three different peroxide concentrations were used for treating the CNF. It was found that both E′ and E increase with CNF concentration and, in addition, increase further with the peroxide treated CNFs. Nonetheless, it was found that the greater the peroxide concentration used in treating the CNF, the greater the PS degradation via free radical attack on the polymer chain, with the corresponding negative effect on the storage and tensile modulus. Dispersion of the CNF was assessed using scanning and optical microscopy, and the positive effect of the peroxide treatment on the dispersion of the CNF is evidenced.

Tensile stress‐strain behavior of PS/CNF nanocomposites.

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Tensile stress‐strain behavior of PS/CNF nanocomposites.
Crypticity and functional distribution of the membrane associated α‐L‐fucosidase of human sperm
Authors: Venditti Jennifer J. , Donigan Katherine A. , Bean Barry S.
Published: November 2006

Two distinctive isoforms of the enzyme α‐L‐fucosidase are found within human semen in substantial amounts, suggesting specialized functions during reproduction. The membrane‐associated isozyme of human sperm cells was previously characterized biochemically, and here we report on its subcellular localization. Intact, detergent permeabilized, capacitated, and acrosome‐reacted sperm were investigated using antifucosidase immunofluorescence, binding of the fluorescent fucosylated glycoconjugate RITC‐BSA‐fucose (RBF), and enzyme activity in the presence and absence of selected inhibitors. Both immunolocalization and RBF binding show that fucosidase is broadly distributed over the membrane systems of human sperm, but is relatively enriched within the equatorial segment. Upon detergent treatment or induction of acrosome reaction (AR), a portion of enzyme activity is recoverable in the supernatant, presumably associated with released remnants of the outer acrosomal membrane. Surprisingly, cell‐bound enzyme activity increases sharply following permeabilization of intact sperm, representing cryptic fucosidase that is relatively stable and corresponds with strong fluorescence in the equatorial segment and other sperm membranes. These observations support the notion that the fucosidase has a role in the intimate species signature interactions between sperm and oocyte. Mol. Reprod. Dev. 74: 758–766, 2007. © 2006 Wiley‐Liss, Inc.
Ultrastructural analysis reveals striking differences of intercellular contact lengths in bovine embryos produced in vivo, in vitro and by somatic cell nuclear transfer
Authors: Bhojwani S. , Tomek W. , Jonas L. , Becker F. , Alm H. , Torner H. , Kanitz W. , Poehland R.
Published: November 2006

Cellular coherence and communication, thus cell‐to‐cell contact is an indispensable premise to sustain the formation of complex, multi‐cellular organisms. We have analyzed intercellular contact lengths in NT‐cloned bovine embryos compared to the in vivo or in vitro produced counterparts. Therefore, ultrastructural analysis was carried out by transmission electron microscopy (TEM) at the 8‐cell and blastocyst stage of development. To obtain embryos generated in vivo, oviducts of superovulated cows were flushed 3 days after insemination, subsequent to slaughter. Standard in vitro maturation (IVM) and ‐fertilization (IVF) were utilized to obtain in vitro embryos. Cloned embryos by somatic nuclear transfer were produced by the handmade cloning (HMC™) procedure. The points of apposition/focal contact points (CPs) between the blastomeres were of the shortest order in cloned embryos (236 ± 135 nm) and of highest order in the in vivo produced embryos (2,085 ± 1,540 nm), although no significant differences regarding the blastomere sizes in the various groups of 8‐cell embryos could be established. In summary, the CP lengths in case of in vitro and in vivo 8‐cell embryos were, on an average, five or nine times longer, respectively, than in the case of the cloned embryos. These differences of CP lengths vanished in embryos reaching the blastocyst stage of embryonic development in all the three groups of embryos. The observed differences of intercellular contact length at distinct stages of embryonic development could be responsible for differences in intercellular communication between the blastomeres at the beginning of cellular differentiation. These may be one reason for the lower developmental competence of cloned (NT) embryos. Mol. Reprod. Dev. 74: 775–784, 2007. © 2006 Wiley‐Liss, Inc.
Conjugate gradient method for the Robin inverse problem associated with the Laplace equation
Authors: Jin Bangti
Published: November 2006

This paper studies a non‐linear inverse problem associated with the Laplace equation of identifying the Robin coefficient from boundary measurements. A variational formulation of the problem is suggested, thereby transforming it into an optimization problem. Mathematical properties relevant to its numerical computation are established. The optimization problem is solved using the conjugate gradient method in conjunction with the discrepancy principle, and the algorithm is implemented using the boundary element method. Numerical results are presented for several benchmark problems with both exact and noisy data, and the convergence of the algorithm with respect to mesh refinement and decreasing the amount of noise in the data is investigated. Copyright © 2006 John Wiley & Sons, Ltd.
The role of ionic liquids in co‐catalysis of Baylis‐Hillman reaction: interception of supramolecular species via electrospray ionization mass spectrometry
Authors: Santos Leonardo Silva , DaSilveira Neto Brenno A. , Consorti Crestina S. , Pavam Cesar Henrique , Almeida Wanda P. , Coelho Fernando , Dupont Jairton , Eberlin Marcos N.
Published: November 2006

The Baylis–Hillman reaction is a general and multifaceted method for CC bond formation in organic synthesis. Using electrospray ionization mass spectrometry in both the positive and negative ion modes, we performed on‐line monitoring of the reaction in the presence of imidazolium ionic liquids. Loosely bonded supramolecular species formed by coordination of neutral reagents, products and the protonated forms of zwitterionic Baylis–Hillman intermediates with cations and anions of ionic liquids were gently and efficiently transferred directly from the solution to the gas phase. Mass measurements and structural characterization of these unprecedented species via collision‐induced dissociation in tandem mass spectrometry experiments were performed. The interception of several supramolecular species indicates that ionic liquids co‐catalyze Baylis–Hillman reactions by activating the aldehyde toward nucleophilic enolate attack and by stabilizing the zwitterionic species that act as the main BH intermediates. Copyright © 2006 John Wiley & Sons, Ltd.
Complex intermediates in the NO insertion reactions into lithium amides
Authors: Vázquez Alvaro , Nudelman N. Sbarbati
Published: November 2006

Nitric oxide (NO) is known to produce the carcinogenetic nitrosamines but it has also been recently reported, both as a regulator of many important physiological functions and as a possible pharmaceutical delivery system. The present paper describes the NO insertion into NLi bond of lithium amides, to afford very good to almost quantitative yields of N‐nitrosamines. A study of the reaction intermediate suggested a further advantage of this synthetic methodology, widening its scope to its use in tandem reactions. Thus, in situ addition of an organolithium reagent into the NO bond leads to an almost quantitative conversion into the corresponding hydrazone. This compound could further add a second equivalent of the same (or another) organolithium affording substituted hydrazines. The hydrazines thus prepared have a potential chiral carbon, by running the reaction in the presence of a chiral auxiliary, enantiomeric excess could be obtained. By reducing the compound with Raney Ni, the scope of this methology could be enlarged for the potential preparation of chiral primary amines, project that is currently under progress. Copyright © 2006 John Wiley & Sons, Ltd.
Hydrological connectivity and seasonal storage change of tundra ponds in a polar oasis environment, Canadian High Arctic
Authors: Woo Ming‐Ko , Guan Xiu Juan
Published: November 2006

Tundra ponds are a common type of wetland in the High Arctic. Their preservation is predicated upon ample water supply and storage to overcome evaporation losses. Two years of hydrological study of a cluster of ponds in a polar oasis of the Canadian Arctic showed the dominance of overland flow in the spring as an agent that recharged the pond storage. The freshet produced by snowmelt gave rise to extensive surface flow connections between the ponds and with their surrounding areas, but such flow connectivity lasted only about 2 weeks. After that, the ponds appeared to be separated from lateral drainage. Detailed mapping of the water and frost table positions together with water balance investigation, however, indicated the presence of subsurface flows between some ponds and with their adjacent slope. The flow magnitude was small relative to the vertical processes of evaporation and rainfall. Evaporation loss was mainly responsible for storage depletion, leading to a decline in pond level and shrinkage of open water area, unless major rain events restored the storage (as in 2006). It is postulated that climate warming could increase evaporation and active layer thickness to promote greater loss in surface water storage, or geomorphic processes could breach the pond rims, leading to the demise of ponds. Copyright © 2006 John Wiley & Sons, Ltd.
Profiles of temporal thaw depths beneath two arctic stream types using ground‐penetrating radar
Authors: Brosten Troy R. , Bradford John H. , McNamara James P. , Zarnetske Jay P. , Gooseff Michael N. , Bowden W. Breck
Published: November 2006

Thaw depths beneath arctic streams may have significant impact on the seasonal development of hyporheic zone hydraulics. To investigate thaw progression over the 2004 summer season we acquired a series of ground‐penetrating radar (GPR) profiles at five sites from May–September, using 100, 200 and 400 MHz antennas. We selected sites with the objective of including stream reaches that span a range of geomorphologic conditions on Alaska's North Slope. Thaw depths interpreted from GPR data were constrained by both recorded subsurface temperature profiles and by pressing a metal probe through the active layer to the point of refusal. We found that low‐energy stream environments react much more slowly to seasonal solar input and maintain thaw thicknesses longer throughout the late season whereas thaw depths increase rapidly within high‐energy streams at the beginning of the season and decrease over the late season period. Copyright © 2006 John Wiley & Sons, Ltd.
Frost boils and soil ice content: field observations
Authors: Overduin P. P. , Kane D. L.
Published: November 2006

Our aim is to measure and explain the seasonal changes in soil ice content in the frost boils of Galbraith Lake, Alaska. Instruments were installed in a frost boil to monitor the ground surface position and soil state over a period of 4 years. By comparing the subsidence and thaw rates, we calculate the soil ice content as a function of depth. Measured soil temperatures, liquid water contents and bulk apparent thermal conductivities are used to estimate latent heat production and release in the soil. The frost boil heaves during freezing and settles during thaw while the surrounding tundra heaves negligibly, but subsides measurably. Despite large changes in freezing rates from year to year, total heave and its distribution across the frost boil are similar between years. Winter air temperature and snow depth influence the freezing rate and ice distribution as a function of depth, but not the overall heave. This suggests that heave is controlled by water availability rather than the rate of heat removal from the soil. Areal ground subsidence rates between 2 and 5 cm/yr are due to the disappearance of ice at the base of the active layer, raising the possibility of ongoing thermokarst expansion around Galbraith Lake. Copyright © 2006 John Wiley & Sons, Ltd.
Riverbank freeze‐thaw erosion along a small mountain stream, Nikko volcanic area, central Japan
Authors: Yumoto Manabu , Ogata Takayuki , Matsuoka Norikazu , Matsumoto Eiji
Published: November 2006

Processes of riverbank erosion involve fluvial entrainment, mass failure and subaerial erosion. The role of freeze‐thaw action in these erosion processes was investigated along a small mountain stream in a region with seasonal frost. Riverbank profiles, horizontal erosion, soil temperature, frost depth and soil water content were monitored over 20 months including two winters. Diurnal and annual freeze‐thaw action directly triggers subaerial erosion and indirectly contributes to mass failure and fluvial entrainment. The rate of subaerial erosion reaches a maximum during the thawing period, reinforced by increasing water content and decreasing soil hardness. The subaerial erosion, which occurs uniformly along the riverbank and recurs every year, contributes to progressive deepening of a notch developed above the water level as both preparatory and erosive processes. The overdeepening of the notch decreases bank stability, followed by occasional mass failure immediately after the thawing period and periodic fluvial entrainment during the summer flood period. The annual amount of subaerial erosion is comparable to that of fluvial entrainment. These observations demonstrate that freeze‐thaw erosion plays a fundamental role in erosion of riverbanks subject to deep seasonal frost. Copyright © 2006 John Wiley & Sons, Ltd.
Assessment of the Gould‐Shih procedure for sample size re‐estimation
Authors: Waksman Joel A.
Published: November 2006

The power of a clinical trial is partly dependent upon its sample size. With continuous data, the sample size needed to attain a desired power is a function of the within‐group standard deviation. An estimate of this standard deviation can be obtained during the trial itself based upon interim data; the estimate is then used to re‐estimate the sample size. Gould and Shih proposed a method, based on the EM algorithm, which they claim produces a maximum likelihood estimate of the within‐group standard deviation while preserving the blind, and that the estimate is quite satisfactory. However, others have claimed that the method can produce non‐unique and/or severe underestimates of the true within‐group standard deviation. Here the method is thoroughly examined to resolve the conflicting claims and, via simulation, to assess its validity and the properties of its estimates. The results show that the apparent non‐uniqueness of the method's estimate is due to an apparently innocuous alteration that Gould and Shih made to the EM algorithm. When this alteration is removed, the method is valid in that it produces the maximum likelihood estimate of the within‐group standard deviation (and also of the within‐group means). However, the estimate is negatively biased and has a large standard deviation. The simulations show that with a standardized difference of 1 or less, which is typical in most clinical trials, the standard deviation from the combined samples ignoring the groups is a better estimator, despite its obvious positive bias. Copyright © 2006 John Wiley & Sons, Ltd.
Potential cytotoxic activity of some Brazilian seaweeds on human melanoma cells
Authors: Rocha Fabíola Dutra , Soares Angélica Ribeiro , Houghton Peter John , Pereira Renato Crespo , Kaplan Maria Auxiliadora Coelho , Teixeira Valéria Laneuville
Published: November 2006

In vitro screening of the crude extracts of some Brazilian coastal seaweeds for cytotoxic activity against a cultured human melanoma cancer cell line using the sulphorhodamine B assay was performed. The crude dichloromethane:chloroform extract of Stypopodium zonale showed good cytotoxic activity against the C32 cell line. The crude acetone extract and aqueous phase of Lobophora variegata did not show any activity, but semi‐purified fractions XAD LOB I and II could inhibit the growth of melanoma cells. The crude acetone extract of Caulerpa racemosa showed some cytotoxicity, but caulerpin isolated from this extract did not show any such activity. The crude acetone extract of Spatoglossum schroederi was not able to inhibit the growth of C32 melanoma cells. Copyright © 2006 John Wiley & Sons, Ltd.
Quantification of D‐amino acids in the central nervous system of Aplysia californica by liquid chromatography/tandem mass spectrometry
Authors: Song Yaru , Liang Fei , Liu Yi‐Ming
Published: November 2006

A sensitive, specific and reliable liquid chromatography/tandem mass spectrometry (LC/MS/MS) method has been developed for simultaneous determination of D‐amino acids in the central nervous system (CNS) of Aplysia californica. In order to correct for any potential matrix effects on measured signals, deuterium‐labeled L‐Asp‐d3 was used as an internal standard. Pre‐column derivatization of the sample with 7‐fluoro‐4‐nitrobenzoxadiazole (NBD‐F) allowed both effective in‐line pre‐concentration and sensitive MS/MS detection of the analytes. An extraction column (50 × 0.25 mm, 5 µm C18 silica particles) was used to pre‐concentrate/stack samples. Enantiomeric separation of amino acid enantiomers was achieved on a chiral column packed with teicoplanin aglycone bonded silica particles (170 × 0.25 mm, 5 µm) with an MS‐friendly mobile phase. The characteristic precursor to product ion transitions, m/z 297 → 279 (for NBD‐Asp), m/z 269 → 223 (For NBD‐Ser), m/z 311 → 293 (for NBD‐Glu) and m/z 300 → 282 (for NBD‐L‐Asp‐d3) were monitored for the quantification. Samples from the CNS of A. californica and heart tissues were analyzed. D‐Asp was detected at high levels in all the ganglia and nerve tissues, but not in the heart tissue. Further, neither D‐Ser nor D‐Glu was detected in Aplysia, a widely used neuronal model. Copyright © 2006 John Wiley & Sons, Ltd.
Evaluation of an on‐target sample preparation system for matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry in conjunction with normal‐flow peptide high‐performance liquid chromatography for peptide mass fingerprint analyses
Authors: McComb Mark E. , Perlman David H. , Huang Hua , Costello Catherine E.
Published: November 2006

Large‐scale mass spectrometry (MS)‐based proteomic analyses require high‐throughput sample preparation techniques due to the increasing numbers of samples that make up a typical proteomics experiment. Moreover, extensive sample pre‐treatment steps are necessary prior to MS acquisition for even the most rapid and robust MS‐based proteomics methodology, matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) MS followed by peptide mass fingerprinting (PMF) analysis. These include sample purification and fractionation, removal of digestion buffers or solvents, and spotting of sample with matrix onto the MALDI target. These multiple steps of time‐consuming sample handling can result in high overall analysis costs and the likelihood of sample contamination and loss. In order to overcome some of these limitations in sample processing, we have investigated the use of a novel, simple, inexpensive 96‐well elastomeric array that affixes to a MALDI target to create an on‐target 96‐well plate that accommodates a high solution volume (ca. 200 µL), thereby enabling the on‐target processing of samples for MALDI‐TOFMS. We explored several factors that influence MALDI sample preparation: type of matrix, solution volume, solution organic composition, solution drying rates and matrix/analyte co‐crystallization methods. We also investigated the use of the 96‐well elastomeric device for coupling MALDI‐TOFMS analysis directly to high flow rate (1 mL/min) reversed‐phase (rp)‐HPLC. By developing an optimized, robust sample preparation protocol, we were able to obtain mass spectra with a high signal‐to‐noise ratio from peptide standards present at the 50‐fmol level in large starting volumes of solution. PMF analyses were possible from 1‐pmol and 500‐fmol protein‐digest standards. Coupling the device to high‐flow HPLC (750 µL/min) yielded a robust and semi‐automated means to obtain enhanced MALDI‐TOFMS data at 500 ng of protein digest. These methodologies developed for this simple, on‐target, elastomeric device show promise for streamlining the sample preparation process from HPLC to MALDI‐MS. Copyright © 2006 John Wiley & Sons, Ltd.