bluuebunny/crossref_metadata_2025 huggingface dataset:
R1514Q substitution in Lrrk2 is not a pathogenic Parkinson's disease mutation
Authors: Nichols William C. , Marek Diane K. , Pauciulo Michael W. , Pankratz Nathan , Halter Cheryl A. , Rudolph Alice , Shults Clifford W. , Wojcieszek Joanne , Foroud Tatiana
Published: December 2006

Mutations in LRRK2 were first reported as causing Parkinson's disease (PD) in late 2004. Since then, approximately a dozen LRRK2 substitutions have been identified that are believed to be pathogenic mutations. The substitution of adenine for guanine at nucleotide 4541 (4541G>A) in LRRK2 was recently reported. This substitution resulted in the replacement of an arginine at position 1514 with a glutamine (R1514Q). Although this substitution was not found in a large cohort of controls, its pathogenicity could not be verified. We have now genotyped the R1514Q substitution in a sample of 954 PD patients from 429 multiplex PD families. This substitution was identified in 1.8% of the PD patients; however, the majority of the PD sibships segregating this substitution were discordant for this putative mutation. In addition, the R1514Q substitution was detected in 1.4% of neurologically evaluated, control individuals. These data suggest that the R1514Q variant is not a pathogenic LRRK2 mutation. We believe it is imperative that the causative nature of any newly identified genetic variant be determined before it is included in any panel for diagnostic testing. © 2006 Movement Disorder Society
Joubert syndrome surviving to adulthood associated with a progressive movement disorder
Authors: Gunzler Steven A. , Stoessl A. Jon , Egan Robert A. , Weleber Richard G. , Wang Paul , Nutt John G.
Published: December 2006

A 48‐year‐old man presented with a progressive gait disorder. He had longstanding ataxia, oculomotor apraxia, motor delay, and cognitive impairment, diagnosed as cerebral palsy. Physical examination revealed ataxia, oculomotor apraxia, extrapyramidal signs, and a wide‐based, shuffling gait. Magnetic resonance imaging showed vermian aplasia, consistent with Joubert syndrome. Positron emission tomography scan revealed normal fluorodopa uptake, but elevated raclopride binding, compatible with dopamine deficiency. This case demonstrates that a patient with Joubert syndrome may survive into adulthood and present as a chronic neurologic disorder with subacute extrapyramidal signs. © 2006 Movement Disorder Society
Health‐related quality of life in sporadic adult‐onset ataxia
Authors: Abele Michael , Klockgether Thomas
Published: December 2006

Despite progressive disability in sporadic adult‐onset ataxia (SAOA), little is known about patients' assessment of their ataxic disorder and its impact on health‐related quality of life (Hr‐QoL). This study investigated Hr‐QoL by means of the following self‐administered scales: Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, Beck Depression Inventory (BDI), and the Medical Outcome Study Short Form (SF‐36). Twenty‐two unselected ataxia patients were included. Sleep‐related complaints were found in 9 (41%) of 22 and symptoms of depression in 6 (38%) of 16 patients. Compared to a large german control group, SAOA patients had lower scores in all SF‐36 dimensions except for bodily pain. The greatest impairment was found in the domain physical functioning, followed by the domains social functioning and role limitations (emotional problems). There was a significant negative correlation of all nonmotor SF‐36 dimensions with the BDI score. Walking aid dependency was significantly correlated with poorer health status perception in several motor and nonmotor domains. In addition, impaired sleep quality was correlated with an impaired general health perception and with bodily pain. The study demonstrates a great impact of SAOA on Hr‐QoL. Adequate treatment of depression, motor disability, and impaired sleep quality is essential to improve Hr‐QoL in ataxic patients. © 2006 Movement Disorder Society
Hypomyelinating leukoencephalopathy with paroxysmal tonic upgaze and absence of psychomotor development
Authors: Blumkin Lubov , Lev Dorit , Watemberg Nathan , Lerman‐Sagie Tally
Published: December 2006

Hypomyelinating leukoencephalopathies are characterized by a substantial and permanent deficit in myelin deposition in the brain. Although our knowledge and understanding of the etiology of white matter diseases has progressively increased, many cases with this disorder remain undiagnosed, despite extensive evaluations. Recently, new disease entities have been defined by combining magnetic resonance imaging pattern recognition and clinical features. We describe a 1‐year‐old Ashkenazi Jewish girl with a hypomyelinating leukoencephalopathy, who presented in the neonatal period with episodes of sustained paroxysmal tonic upward gaze, roving eye movements, pendular nystagmus, and severe hypotonia, with the later appearance of pyramidal and extrapyramidal signs and no development. In addition, she has dysmorphic signs. This clinical picture is not consistent with any of the previously described hypomyelinating leukoencephalopathies and may represent a new entity. © 2006 Movement Disorder Society
A double‐blind placebo‐controlled trial of zonisamide (zonegran) in the treatment of essential tremor
Authors: Zesiewicz Theresa A. , Ward Christopher L. , Hauser Robert A. , Sanchez‐Ramos Juan , Staffetti Joseph F. , Sullivan Kelly L.
Published: December 2006

Medical therapy for essential tremor (ET), a common movement disorder, is often inadequate. We performed a double‐blind placebo‐controlled randomized trial to evaluate the efficacy and tolerability of zonisamide (ZNS), an antiepileptic agent, in treating ET. Twenty patients (mean age, 60 ± 15 years) with ET were randomized to receive ZNS or placebo. ZNS was initiated at a dosage of 100 mg/day and escalated to 200 mg/day at day 14. Patients were evaluated by accelerometry and the Fahn–Tolosa–Marin (FTM) rating scale at baseline and days 14 and 28, as well as the Clinical Global Impression (CGI‐C) scale at day 28. At endpoint, subjects assigned to ZNS were taking a mean dosage of 160 ± 50 mg/day. There were no significant improvements in the FTM total score or its subsections. Tremor amplitude as assessed by accelerometry significantly improved in the ZNS group compared to the placebo group at endpoint relative to baseline (−0.50 ± 0.72 vs. 0.30 ± 0.79 m/s2; P = 0.03). On the CGI‐C, 60% (n = 6) of patients in the ZNS group felt that their tremor was unchanged, while the remaining patients felt that their tremor was “minimally improved.” Thirty percent (n = 3) of patients taking ZNS discontinued the study due to side effects (fatigue, headache, paresthesias) while taking 100 mg per day. ZNS did not provide significant improvements in clinical rating scales at study endpoint compared to placebo and was only modestly well tolerated. ZNS was effective in reducing tremor amplitude as measured by accelerometry. © 2006 Movement Disorder Society
NMR structure of the peptidyl transferase RNA inhibitor antibiotic amicetin
Authors: Shammas Christos , Donarski James A , Ramesh Vasudevan
Published: December 2006

In this communication, we report the solution state NMR structure determination of the peptidyl transferase RNA inhibitor antibiotic amicetin. We have successfully characterised the NMR spectrum of amicetin using a range of homo‐ and heteronuclear NMR techniques. Using experimental ROE‐based distance and 1H1H scalar coupling derived dihedral angle geometrical constraints as input into the three‐dimensional structure determination protocol, we have generated an energy‐minimised average structure of the antibiotic. Amicetin adopts a stable well‐folded conformation in solution, mediated by a network of hydrogen bonds caused by proton donor and acceptor groups at either end of the molecule. The NMR structure of amicetin shows that the cytosine moiety occupies the critical turn position within the fold, which may be structurally significant for interaction with peptidyl transferase ribosomal RNA. The structure is distinctly different from the published X‐ray crystal structure of amicetin in which it adopts a linear, extended chain‐like conformation with a number of intermolecular hydrogen bonds. In addition to structure, we have probed the dynamics of amicetin in solution and have observed retarded exchange of the amide proton involved in folding. We have also characterised the ionisation properties of amicetin by carrying out NMR pH titration and measuring the pKa of the primary and tertiary amino groups, 7.27 and 7.52, respectively, which are in agreement with the reported values in literature. Solving the NMR structure of amicetin provides a valuable opportunity to determine the structure of its complex with RNA in solution state. Copyright © 2006 John Wiley & Sons, Ltd.
Propagation of a shear band in sandstone
Authors: Riedel J. J. , Labuz J. F.
Published: December 2006

Closed‐loop, servo‐controlled experiments were conducted to investigate the development of a shear band in Berea sandstone at various confining pressures. The tests were performed with the University of Minnesota Plane‐Strain Apparatus, which was designed to allow the shear band to develop in an unrestricted manner. Measured load and displacements provided estimates of the stress and deformation states whereby dilatancy and friction were evaluated prior to localization. Experiments were stopped at various stages of shear‐band development within the strain‐softening regime. The specimens displayed a progression of deformation from inception, where the shear band was characterized by a high density of intragranular microcracks and crushed grains, to the tip where the intragranular microcracks were significantly less dense and separated by intact grains. Decreased slip deformation towards the tip of the shear band indicated that localization developed and propagated in plane. Thin‐section microscopy showed porosity increase within the shear band was 3–4 grain diameters wide. Increased porosity did not extend beyond the tip of the shear band. A cohesive zone model of shear fracture, used to examine the stress field near the tip, showed similarities to principal compressive stress orientations interpreted from intragranular microcracks. Thus, propagation of the shear band could be associated with in‐plane mode II fracture. Copyright © 2006 John Wiley & Sons, Ltd.
Detrusor overactivity and urge urinary incontinence following trans obturator versus midurethral slings
Authors: Botros Sylvia M. , Miller Jay‐James R. , Goldberg Roger P. , Gandhi Sanjay , Akl Mohammed , Beaumont Jennifer L. , Sand Peter K.
Published: December 2006

Aims

To compare the rates of resolution of detrusor overactivity (DO) and subjective urge urinary incontinence (UUI) as well as de novo DO and UUI between the Monarc, TVT, and SPARC midurethral sling procedures.

Methods

Two hundred and seventy‐six subjects with urodynamic stress or mixed urinary incontinence underwent retropubic midurethral slings (TVT, N = 99; SPARC, N = 52) or transobturator slings (Monarc, N = 125). All evaluable subjects had a routine office evaluation, subjective assessment of UUI, and multichannel urodynamic testing pre‐ and 3 months postoperatively. Comparisons were made using Student's t‐test, ANOVA, McNemar's test, and Chi‐Square test where appropriate. Multivariate logistic regression was performed to detect possible confounding factors such as sling type, and differences in concomitant surgical procedures.

Results

De novo subjective UUI differed significantly between the Monarc and the other two slings (33% TVT vs. 8% Monarc vs. 17% SPARC, P = 0.04). Fourteen to Sixteen percents of patients with preoperative UUI who underwent TVT or SPARC had worsening of their UUI symptoms while only 6% of the Monarc group did (P = 0.02). There was no difference in rates of resolution of DO among the three groups (40% vs. 48% vs. 32%, P = 0.39) or de novo DO (32% vs. 22% vs. 22%, P = 0.64) at 3 months.

Conclusions

Patients who undergo transobturator procedures have significantly lower rates of de novo UUI than those who undergo midurethral sling procedures. Rates of resolution of DO, UUI, and de novo DO do not differ between groups. Neurourol. Urodynam. © 2006 Wiley‐Liss, Inc.
2‐DE profiling of GDNF overexpression‐related proteome changes in differentiating ST14A rat progenitor cells
Authors: Hoffrogge Raimund , Beyer Susanne , Hübner Rayk , Mikkat Stefan , Mix Eilhard , Scharf Christian , Schmitz Ulf , Pauleweit Stefan , Berth Matthias , Zubrzycki Igor Z. , Christoph Hilmar , Pahnke Jens , Wolkenhauer Olaf , Uhrmacher Adelinde , Völker Uwe , Rolfs Arndt
Published: December 2006

Targeted differentiation of neural progenitor cells (NPCs) is a challenge for treatment of neurodegenerative diseases by cell replacement therapy and cell signalling manipulation. Here, we applied a proteome profiling approach to the rat striatal progenitor model cell line ST14A in order to elucidate cellular differentiation processes. Native cells and cells transfected with the glial cell line‐derived neurotrophic factor (GDNF) gene were investigated at the proliferative state and at seven time points up to 72 h after induction of differentiation. 2‐DE combined with MALDI‐MS was used to create a reference 2‐DE‐map of 652 spots of which 164 were identified and assigned to 155 unique proteins. For identification of protein expression changes during cell differentiation, spot patterns of triplicate gels were matched to the 2‐DE‐map. Besides proteins that display expression changes in native cells, we also noted 43 protein‐spots that were differentially regulated by GDNF overexpression in more than four time points of the experiment. The expression patterns of putative differentiation markers such as annexin 5 (ANXA5), glucosidase II beta subunit (GLU2B), phosphatidylethanolamine‐binding protein 1 (PEBP1), myosin regulatory light chain 2‐A (MLRA), NASCENT polypeptide‐associated complex alpha (NACA), elongation factor 2 (EF2), peroxiredoxin‐1 (PRDX1) and proliferating cell nuclear antigen (PCNA) were verified by Western blotting. The results reflect the large rearrangements of the proteome during the differentiation process of NPCs and their strong modification by neurotrophic factors like GDNF.
Proteomic analysis of glutamate‐induced toxicity in HT22 cells
Authors: Lee Youra , Park Hye‐won , Park Sung Goo , Cho Sayeon , Myung Pyung Keun , Park Byoung Chul , Lee Do Hee
Published: December 2006

In the present study, we have investigated the proteome changes associated with glutamate‐induced HT22 cell death, a model system to study oxidative stress‐mediated toxicity. Among a number of HT22 proteins exhibiting altered expression, several molecular chaperones demonstrated substantial changes. For example, the levels of Hsp90 and Hsp70 decreased as cell death progressed whereas that of Hsp60 increased dramatically. Interestingly, cytosolic Hsp60 increased more prominently than mitochondrial Hsp60. Concomitantly, the accumulation of poly‐ubiquitylated proteins and differential regulation of the peptidase activities and the subunits of 26S proteasomes were observed in glutamate‐treated HT22 cells. Our findings that the molecular chaperones and the ubiquitin‐proteasome system undergo changes during glutamate‐induced HT22 cell death may suggest the importance of a protein quality control system in oxidative damage‐mediated toxicity.
Ab initio calculations of the gas‐phase elimination kinetics of ethyl oxamate, ethyl oxanilate, and ethyl N,N‐dimethyl oxamate
Authors: Mora Jose R. , Loroño Marcos , Cordova Tania , Chuchani Gabriel
Published: December 2006

Theoretical studies of the gas‐phase elimination kinetics of title compounds were performed by using “ab initio” methods at MP2/6‐31G, MP2/6‐31G(d,p) and ONIOM [MP2/6‐31G (d,p) // MP2/6‐31G]. Ethyl Oxamate and ethyl oxanilate undergo a rapid decarbonylation to give the corresponding carbamates. These intermediates proceed to a parallel decomposition to give the corresponding unstable carbamic acid and ethylene through six‐membered cyclic transition state (path 1) and isocyanate and ethanol through a four‐membered cyclic transition state (path 2). Ethyl N,N‐dimethyloxamate elimination reaction yields in one step, through a six‐membered cyclic transition state, dimethyl oxamic acid and ethylene gas. The calculated bond orders, NBO charges and synchronicity indicate that these reactions are concerted and slightly asynchronous. The estimated kinetic and thermodynamic parameters are in good agreement with the reported experimental values. Copyright © 2006 John Wiley & Sons, Ltd.
Substituted polyacetylenes
Authors: Masuda Toshio
Published: December 2006

This article reviews the chemistry of substituted polyacetylenes developed by our research group, more specifically, development of polymerization catalyst, synthesis of new polymers, elucidation of their structure, investigation of their properties, and development of their functions. The main features are as follows: a number of catalysts based on group 5, 6, and 9 transition metals (Nb, Ta, Mo, W, and Rh) have been developed, which include living polymerization catalysts. By using these catalysts, many new substituted polyacetylenes have been synthesized, whose molecular weights are very high (Mw = 104−106). Most of the polymers are soluble in many common solvents and stable enough in the air unlike polyacetylene. Some of these polymers exhibit interesting functions including high gas permeability and photoelectronic properties. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 165–180, 2007
X‐ray photoelectron and carbon Kα emission measurements and calculations of O‐, CO‐, N‐, and S‐containing substances
Authors: Shimada Shingo , Hiroi Toshiyuki , Ida Tomonori , Mizuno Motohiro , Endo Kazunaka , Kurmaev Ernst Z. , Moewes Alexander
Published: December 2006

X‐ray fluorescence measurements for O‐containing [polyethylene oxide, polyvinyl alcohol, polyvinyl methyl ether], CO‐containing [polyvinyl methyl ketone, polyethylene terephthalate], N‐containing [poly‐4‐vinylpyridine (P4VP), polyaniline oligomer (PAO)], and S‐containing [polyphenylene sulfide] substances are presented. Carbon Kα X‐ray emission spectra (XES) and X‐ray photoelectron spectra (XPS) are compared with our DFT calculations performed with the Amsterdam density functional (ADF) program. The combined analysis of valence XPS and carbon Kα XES allows us to determine the individual contributions from pσ‐ and pπ‐bonding molecular orbitals of the polymers. The ΔSCF calculations yield the accurate C1s core‐electron binding energies (CEBEs) for all carbon sites of the organic compound. We calculate all CEBEs of the model molecules using the ΔEKS approach. Our simulated C1s photoelectron and C Kα emission spectra are in good agreement with our measurements. We also obtain WD (work function and the other energies) values for the polymers and PAO from the difference between calculated (gas‐phase) and measured (solid) CEBE values. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 162–172, 2007
Comparison of membrane‐associated proteins in human cholangiocarcinoma and hepatocellular carcinoma cell lines
Authors: Srisomsap Chantragan , Subhasitanont Pantipa , Sawangareetrakul Phannee , Chokchaichamnankit Daranee , Ngiwsara Lukana , Chiablaem Khajeelak , Svasti Jisnuson
Published: December 2006

Cholangiocarcinoma (CCA) and hepatocellular carcinoma (HCC) occur with relatively high incidence in Thailand. Cell line models, originating from Thai patients, are available for both diseases, including the human bile duct epithelial carcinoma cell line (HuCCA‐1) and the HCC cell line HCC‐S102. Here, we have prepared subproteomes enriched in membrane proteins or in cytosolic proteins from the HuCCA‐1 and the HCC‐S102 cell lines. Study of differential protein expression by 2‐DE and LC/MS/MS showed 195 proteins expressed in the two cell lines, including both membrane‐associated and cytosolic proteins. Eighteen proteins were found in both membrane and cytosolic fractions of HuCCA‐1, but not in HCC‐S102, while nine proteins were found in both membrane and cytosolic fractions of HCC‐S102, but not in HuCCA‐1. Ten membrane proteins were found in HuCCA‐1 but not in HCC‐S102, including integrin alpha‐6 precursor, ezrin, hippocalcin‐like protein 1, mitogen‐activated protein kinase kinase kinase 2 (MAPK/ERK kinase kinase 2), and calgizzarin. Proteins showing increased expression in the membrane fraction of HuCCA‐1 were mainly cytoskeletal proteins (40.9%), while proteins showing increased expression in the membrane fraction of HCC‐S102 were mainly metabolic proteins (39.4%). The subproteomic approach used here facilitates detection of potential biomarkers undetected by regular proteomic methods.
A comparative proteomic study to characterize the vinblastine resistance in human ovarian cancer cells
Authors: Brown Dawn P. G. , Gökmen‐Polar Yesim , Jiang Li , Tan Jian , Ringham Heather , Janecki Dariusz J. , Qi Guihong , Witzmann Frank A. , Sledge George W. , Wang Mu
Published: December 2006

Drug resistance is a major impediment to the successful treatment of human cancers, including ovarian cancer. Vinblastine (VLB), an antimicrotubule agent, is one of the chemotherapeutic drugs that exhibit resistance in ovarian cancer patients. To determine the protein factors that are involved in vinblastine resistance in human ovarian cancer cells, a combination of sample pre‐fractionation and high‐resolution 2‐DE proteomic analysis was performed. Approximately 1200 proteins were detected and quantitatively compared in both nuclear/membrane and cytosolic fractions. Sixty‐nine proteins from the nuclear/membrane fraction showed altered expression levels, whereas 59 were altered in the cytosolic fraction between SKOV3 (vinblastine‐sensitive) and SKVLB (vinblastine‐resistant) cell lines. These proteins include membrane‐associated, chromatin remodeling, cytoskeletal, and microtubule‐associated proteins as well as others that regulate signal transduction. This study not only demonstrates a novel understanding of the mechanism of drug resistance but also provides a valuable resource for future studies on drug resistance to vinblastine. In addition, it also represents a good example of how to increase the protein dynamic range and reduce sample complexity using currently available tools.
Resonant impurity states in PbTe‐based alloys doped with gallium and chromium under pressure
Authors: Skipetrov E. , Golubev A. , Pichugin N. , Plastun A. , Dmitriev N. , Slyn'ko V.
Published: December 2006

The galvanomagnetic effects in the n‐Pb1–x Snx Te:Ga (x = 0.21) and n‐Pb1–y Gey Te:Cr (y = 0.10) alloys at temperatures 4.2 ≤ T ≤ 300 K and under hydrostatic compression up to 17 kbar have been investigated. It is found that in almost the whole investigated pressure range in the samples investigated temperature dependencies of resistivity and Hall coefficient have a “metallic” character, indicating stabilization of the Fermi level by the impurity resonant levels. Using the experimental data in the framework of a two‐band Kane dispersion law the dependencies of the free electron concentration and the Fermi‐level position upon the pressure were calculated. The pressure coefficients of gallium and chromium deep‐level movement were obtained and the models of the electronic‐structure reconstruction under pressure were developed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Raman scattering of capped and uncapped carbon‐induced Ge dots under hydrostatic pressure
Authors: Bernardi A. , Reparaz J. S. , Goñi A. R. , Alonso M. I. , Garriga M.
Published: December 2006

We compare results from Raman scattering for both capped and uncapped Ge quantum dots under hydrostatic pressure. The behavior of lattice vibrations and electronic transitions of the quantum dots are affected by the presence or absence of a cap layer. The pressure coefficient obtained for the Ge mode of relaxed, uncapped islands is close to the corresponding value in bulk, whereas it is reduced by ∼20% in presence of a Si cap layer. This result can be understood by taking into account the change of the boundary condition imposed to the Ge lattice, which is constrained to match that of the silicon matrix. Measurements of the capped sample exhibit a resonant enhancement which is not appreciable for the uncapped dots. We relate this effect to the different lifetime of electronic states. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Strength of strained quantum wells and other small scale structures
Authors: Dunstan D. J. , P'ng K. M. Y. , Zhu T. T. , Hou X. D. , Walker C. J. , Bushby A. J.
Published: December 2006

The strength of a material increases either when the structure is small or when only a small volume is under strain. The term ‘size effect’ covers generically all the ways in which this may happen. One manifestation of the size effect is in epitaxial growth of strained layers, for which critical thickness theory provides a satisfactory explanation. We have extended critical thickness theory to the bending and torsion of foils and wires of soft metals, and have built instruments for measuring the stress‐strain curves of soft metal foils with unprecedented accuracy to test this. Experimentally, semiconductor epitaxial growth provides structures with tailored internal strain distributions, ideal for helping to understand these problems. We have found that internal strains can reduce the strength of a superlattice by a factor of two at room temperature, but on the other hand can increase the strength by a factor of a hundred at high temperature. Nanoindentation on the semiconductor structures also reveals the size effect very clearly. All of these effects are clearly related to the finite volume required for the initiation of plasticity. New data is crucial to reconciling the various theoretical approaches to these problems. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High pressure structure of Tb2Ti2O7 pyrochlore at cryogenic temperatures
Authors: Kumar Ravhi S. , Cornelius Andrew L. , Somayazulu Maddury , Errandonea Daniel , Nicol Malcolm F. , Gardner Jason
Published: December 2006

The structure of Tb2Ti2O7 pyrochlore was investigated at high pressures up to 24 GPa at cryogenic temperatures down to 6.5 K using angular dispersive X‐ray diffraction with synchrotron radiation at HPCAT, Advanced Photon Source. The cell parameters were obtained by performing full profile Rietveld refinements of the diffraction data. The equation of state is obtained at low temperatures by fitting the pressure‐volume data to a second order Birch Murnaghan eqation and a bulk modulus value of 168(4) GPa is obtained. The results show persistance of the pyrochlore structure up to the maximum pressure studied in the experiment and further indicate that pressure induces solely magnetic ordering which do not involve crystal symmetry changes. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
X‐ray diffraction study of amorphous phase of BaSi2 under high pressure
Authors: Nishii T. , Mizuno T. , Mori Y. , Takarabe K. , Imai M. , Kohara S.
Published: December 2006

A high‐pressure synchrotron X‐ray diffraction study of zintl phase BaSi2 semiconductor has been performed up to 45 GPa. The pressure‐induced amorphization occurred at 13 GPa. In the amorphous phase, the Ba–Si bond distance decreased with increasing pressure, while the Ba–Ba bond distances were almost unchanged. The Rietveld refinement revealed that these distances in the crystal phase decreased with increasing pressure. By combining these results, the Ba–Si bond compressibility in both phases is almost identical. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Energetic and electronic properties of BN nanotube bundle under pressure
Authors: Guerini S. , Lemos V. , Piquini P. , Coutinho S. S.
Published: December 2006

Ab initio calculations were performed to study the structural transformation on boron nitride nanotubes bundles under pressure. The (16, 0) zigzag tube circular cross section was observed to suffer an oval deformation. The onset of this transformation was determined as 1 GPa, by observing discontinuous changes in the percent relative volume, and a center to center tube distance. The cohesive energy at the critical point was obtained. The band structure indicates the electronic properties to be preserved through the transition. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New implementation of molecular double point‐group symmetry in four‐component relativistic Gaussian‐type spinors
Authors: Yanai Takeshi , Harrison Robert J. , Nakajima Takahito , Ishikawa Yasuyuki , Hirao Kimihiko
Published: December 2006

A new, practical implementation of double‐group symmetry to relativistic Gaussian spinors is presented for four‐component relativistic molecular calculations. We show that the systematic adaptability to irreducible representations under arbitrary point‐group symmetry, as well as Kramers (time‐reversal) symmetry, is inherent in the present basis spinors, which possess the analytic structure of Dirac atomic spinors. The implementation of double‐group symmetry entails significant computational efficiencies in the relativistic second‐order Møller–Plesset perturbation calculation on Au2 and the density functional theory (DFT) calculation with the B3LYP functional on octahedral UF6, in which the highest symmetries used are, respectively, C and D. The four‐component B3LYP equilibrium geometry of UF6 is reported. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Substituent effects on noncovalent halogen/π interactions: Theoretical study
Authors: Lu Yun‐Xiang , Zou Jian‐Wei , Wang Yan‐Hua , Yu Qing‐Sen
Published: December 2006

Noncovalent halogen/π interactions of FCl with substituted benzenes have been investigated using ab initio calculations. It was shown that the predicted maximum interaction energy gap between the substituted and unsubstituted systems amounts to 1.14 kcal/mol, and therefore substituents on benzene have a pronounced effect on the strength of halogen/π interactions. While the presence of electron‐donating groups (NH2, CH3, and OH) on benzene enhances the interaction energy appreciably, an opposite effect is observed for electron‐accepting groups (NO2, CN, Br, Cl, and F). The large gain of the attraction by electron correlation illustrates that the stabilities of the systems considered arise primarily from the dispersion interaction. Beside the dispersion interaction, the charge‐transfer interaction also plays an important role in halogen/π interactions, as a charge density analysis suggested. To provide more insight into the nature of halogen/π interactions, topological analysis of the electron density distribution and properties of bond critical points were determined in terms of the atoms in molecules (AIM) theory. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Torque teno virus (TTV): current status
Authors: Hino Shigeo , Miyata Hironori
Published: December 2006

Torque teno virus (TTV), currently classified into the family Circoviridae, genus Anellovirus, was first found in a patient with non‐A‐E hepatitis. TTV has a single stranded circular DNA of ∼3.8 kb. TTVs are extraordinarily diverse, spanning five groups including SANBAN and SEN viruses. Torque teno mini virus (TTMV) with ∼2.9 kb genome also has wide variants. Recently, two related 2.2‐ and 2.6‐kb species joined this community. Recombinations between variants are frequent. This extensive TTV diversity remains unexplained; it is unclear how TTVs could be viable, and why they require such genetic variation. An unequivocal culture system is still not available. TTVs are ubiquitous in > 90% of adults worldwide but no human pathogenicity of TTV has been fully established. Epidemiological surveys need to specify the variants being studied and clinical targets, and must calibrate the sensitivity of the assay used. Potentially interesting observations include a higher viral load in patients with severe idiopathic inflammatory myopathies, cancer and lupus. Active replication was also found in infants with acute respiratory diseases. TTV/TTMV‐related viruses were found in chimpanzees, apes, African monkeys and tupaias, and also in chickens, pigs, cows, sheep and dogs. Experimentally, rhesus monkeys were persistently infected by TTV, but only 1/53 chimpanzees. TTV transcribes three species of mRNAs, 3.0‐, 1.2‐ and 1.0‐kb in the ratio of 60:5:35. Recently, at least three mRNAs were shown in chicken anaemia virus. The genomic region −154/−76 contains a critical promoter. TTV seems to have at least three proteins; however, the definite functions of these proteins await further research work. Copyright © 2006 John Wiley & Sons, Ltd.
High Electron Mobility InAs Nanowire Field‐Effect Transistors
Authors: Dayeh Shadi A. , Aplin David P. R. , Zhou Xiaotian , Yu Paul K. L. , Yu Edward T. , Wang Deli
Published: December 2006

Single‐crystal InAs nanowires (NWs) are synthesized using metal–organic chemical vapor deposition (MOCVD) and fabricated into NW field‐effect transistors (NWFETs) on a SiO2/n+‐Si substrate with a global n+‐Si back‐gate and sputtered SiOx/Au underlap top‐gate. For top‐gate NWFETs, we have developed a model that allows accurate estimation of characteristic NW parameters, including carrier field‐effect mobility and carrier concentration by taking into account series and leakage resistances, interface state capacitance, and top‐gate geometry. Both the back‐gate and the top‐gate NWFETs exhibit room‐temperature field‐effect mobility as high as 6580 cm2 V−1 s−1, which is the lower‐bound value without interface‐capacitance correction, and is the highest mobility reported to date in any semiconductor NW.
Pyrolysis of some acetoxynonenes
Authors: List G. R. , Evans C. D. , Selke E. , Glass C. A. , Hoffmann R. L. , McManis G. E.
Published: December 2006

Current studies on odor thresholds of hydrocarbons autoxidatively derived from fats required the preparation of 1,3‐ and 2,4‐nonadienes. The pyrolysis of 3‐acetoxy‐1‐nonene (I) and 4‐acetoxy‐2‐nonene (II) was investigated as a route to 1,3‐ and 2,4‐nonadienes, respectively. The acetates were pyrolyzed over pyrex helices at 400 C. Distilled pyrolyzates were characterized by mass, UV, IR, and NMR spectroscopy, along with gas chromatography. Since II gave approximately a 50∶50 mixture of the 1,3‐ and 2,4‐isomers, an earlier observation was confirmed that allylic esters may rearrange before elimination. Ester I gave about 85% of the 1,3‐isomer and 15% of the 2,4. Presumably the 2,4‐isomer arises from thermal rearrangement. In pyrolysis, both I and II give conjugated products almost exclusively. UV spectroscopy shows ε values in the 24,000 to 28,000 range.
The turnover time of dietary cholesterol in the lactating rat
Authors: Easter D. J.
Published: December 2006

The secretion of dietary 4‐14C‐cholesterol into milk of the rat was determined as a function of post‐feeding time by a single dose technique. The time interval which elapsed before maximum specific radioactivity was reached in milk (17–20 hr after maximum activity in the serum) suggests a route through the mammary gland involving transport of the cholesterol by intracellular membranes. It also suggests that the exogenous cholesterol is incorporated into the milk fat globule membranes rather than into the fat globules during their synthesis within the cell.
Liver phospholipids of rats fed a choline‐deficient diet supplemented with choline or methionine
Authors: Beare‐Rogers Joyce L.
Published: December 2006

The low amount of arachidonic acid in the total phospholipids in the liver of rats fed a standard type of choline‐deficient diet was corrected by either choline or methionine, which also increased food intake. Choline increased the content of this fatty acid in the phosphatidyl ethanolamine but not in the phosphatidyl choline. Methionine increased both the amount of phosphatidyl choline and its content of arachidonic acid.
Lipids of bovine thyroid
Authors: Satyaswaroop P. G.
Published: December 2006

The lipid composition of the freshly slaughtered bovine thyroid tissue has been investigated. The phospholipid patterns of microsomal and mitochondrial fractions obtained from homogenates of bovine thyroids have also been determined. They resemble the phospholipid composition of the corresponding subcellular fractions from other tissues. The fatty acid composition of the various phospholipid species of these subcellular components have also been estimated by gas liquid chromatography. These analyses reveal that the fatty acids are not particularly characteristic of the subcellular organelle but tend to be characteristic of the lipid species. There is a high percentage of nervonic acid (C24∶1) in all the subcellular phospholipid species examined.
The triglyceride composition ofMoringa concanensis seed fat
Authors: Sengupta A. , Sengupta Chandana , Das P. K.
Published: December 2006

Moringa concanensis seed fat and its randomized product have been subjected to pancreatic hydrolysis. Glyceride compositions have been calculated from the original fatty acid composition and those of the monoglycerides produced by hydrolysis. The per cent GS3 content of the interesterified product has also been determined by the combined techniques of thin layer chromatography on silver nitrate impregnated silica gel and colorimetry.
Fluorescent lipids of bovine brain white matter
Authors: Khan Afzal A. , Hess Helen H.
Published: December 2006

Two fluorescent lipids were isolated from a chloroform‐methanol (2∶1 v/v) extract of bovine brain white matter by two‐step preparative thin layer chromatography on Silica Gel G. The first step was performed with chloroform‐diethyl ether‐acetic acid (70∶30∶1 v/v) as developing solvent and revealed a single fluorescent band below the solvent front. The band was scraped off, and the lipid was eluted in chloroform and reapplied to Silica Gel G plates. In the second step, benzene‐methanol‐ethyl acetate (85∶10∶5 v/v) as developing solvent revealed two fluoresent bands (A and B) with Rf values of 0.72 and 0.65. The lipids were eluted and the UV and visible absorption spectra were measured in heptane, as were the excitation and fluorescence spectra. Sulfuric acid absorption spectra (2 and 24 hr treatment at 22 C) as well as the resulting excitation and fluorescence spectra were also determined. The fluorescent lipids reacted positively in a number of nonspecific color tests for steroids, but the chemical nature of these minor components of the neutral lipid fraction remains to be established.
Isovaleroyl triglycerides from the blubber and melon oils of the beluga whale (Delphinapterus leucas)
Authors: Litchfield Carter , Ackman R. G. , Sipos J. C. , Eaton C. A.
Published: December 2006

The fatty acid compositions of the blubber and melon oils from the beluga whale (Delphinapterus leucas) have been determined by gas liquid chromatography (GLC). The melon oil contains a high level (60.1 mole %) of isovaleric acid, substantial amounts of long chain branched acids (16.9%), and very little polyunsaturated material (0.5%). The blubber oil contains less isovaleric (13.2%), fewer long chain branched acids (2.7%), and appreciable amounts (10.9%) of the polyunsaturated acids typical of marine oils. The blubber and melon oils were also examined for lipid class composition by thin layer chromatography on silicic acid, direct GLC of the hydrogenated oil, and gel permeation chromatography. Both oils are composed almost entirely of triglycerides, which can be separated chromatographically into molecules containing 0, 1 and 2 isovaleric acid moieties. No triisovalerin could be detected. The blubber oil contains 68.9 mole % normal triacyl‐, 24.2% diacyl‐monoisovaleroyl‐, and 7.0% monoacyl‐diisovaleroyl‐triglycerides (acyl=long chain acid). Monoacyl‐diisovalerin constitutes 86.7 mole % of the melon oil. This unusual compound may play a role in the echolocation system of the beluga whale.
Sphingolipid biosynthesis by particulate fractions of normal and “Quaking” mouse brain
Authors: Kanfer Julian N. , Sargent Anne
Published: December 2006

No differences were detected in the ability of brain particulate fractions isolated from “Quaking” and normal mice for the incorporation of:14C‐L‐serine into 3‐keto‐dihydrosphingosine; 1‐14C‐stearoyl acid and 1‐14C‐stearoyl CoA into ceramide and14C‐choline from CDP14C‐choline into sphingomyelin.
Total fatty acids of habituated and teratoma tissue cultures of tobacco
Authors: Weete John D.
Published: December 2006

Significant differences in the total fatty acids of habituated and teratoma tissue cultures of tobacco were noted. The teratoma tissues contained 3.2 times more total fatty acids than the habituated, while both tissues differed considerably from the fatty acids of tobacco seedlings used for comparison. Differences in relative concentration for each of the three tissues were also noted.
Sterols in five coastal spermatophytes
Authors: Attaway D. H. , Haug P. , Parker P. L.
Published: December 2006

Sterolic fractions ofRuppia maritima L.,Diplanthera wrightii Aschers,Halophila engelmanni Aschers,Syringodium filiforme Kutzing andThalassia testudinum Konig have been isolated. The sterolic fractions were characterized by IR spectroscopy and tentative identities of their components were determined by gas chromatography and mass spectrometry.
Incorporation and metabolism of fatty acids by cultured dissociated cells from rat cerebrum
Authors: Yavin Ephraim , Menkes John H.
Published: December 2006

Dissociated brain cells in culture incorporate a variety of saturated and unsaturated fatty acids into their cellular lipids. Of the various fatty acids studied, uptake of radioactivity was greatest for stearic acid and decreased progressively with decreasing chain length. Incorporation of radioactivity from linoliec and linolenic acids was more extensive than from oleic acid. Cellular phospholipids and triacylglycerols were labeled preferentially from all fatty acid precursors, with the relative amount of label in phospholipids being greatest when cells were incubated with linolenic acid. Fatty acids underwent desaturation and chain elongation. Changes in the labeling pattern of phospholipid fatty acids in the course of incubation demonstrated precursor‐product relationships for laurate (12∶0), myristate (14∶0), palmitate (16∶0), and stearate (18∶0) and for linolenate (18∶3), eicosapentaenoate (20∶5), docosapentaenoate (22∶5), and docosahexaenoate (22∶6). The appearance of label in 22∶5 and 22∶6 paralleled the entrance of label into the ethanolamine phosphoglyceride fraction. Conversion of linoleate (18∶2 ω6) to arachidonate (20∶4 ω6) could be demonstrated but did not proceed via 18∶3 ω6.
Phospholipids of two strains of dermatophyte,Arthroderma uncinatum
Authors: Kish Zoltan , Cecil Jack R.
Published: December 2006

The phospholipid composition of a mutant strain of the dermatophyteArthroderma uncinatum was compared with that of the wild type. Phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, diphosphatidylglycerol, phosphatidylinositol, and phosphatidic acid were present, and there was marked variation in the amounts of phosphatidylcholine, phosphatidylserine, and phosphatidic acid in the two strains. Thus, the ratio of phosphatidylcholine (wild type) to phosphatidylcholine (mutant) was 2∶1; the ratio of phosphatidylserine (wild type) to phosphatidylserine (mutant) was 3∶1 and the ratio of phosphatidic acid (wild type) to phosphatidic acid (mutant) was 1∶5. In both strains, the predominant fatty acid was 18∶2, with 54.0% in the wild type and 46.7% in the mutant. Qualitatively, the same fatty acids, with the exception of C20∶0, were found in all of the phospholipid classes; C20∶0, both in the mutant strain (5.79%) and the wild type (trace amounts), was associated with phosphatidylserine. There was a significant difference in the rates of growth of the two strains; the mutant strain grew more rapidly than, and produced three times as much mycelium as, the wild type. The mutant strain also produced larger proportions of total lipid and phospholipid than the wild type; there was 20.5% total lipid and ca. 5% phospholipid in the mutant compared with 15.5% total lipid and 2.6% phospholipid in the wild type.
Fatty acid desaturation by mammary gland microsomes from lactating mice
Authors: Ananda Rao G. , Abraham S.
Published: December 2006

Microsomal fractions obtained from lactating mouse mammary glands catalyze the desaturation of myristic, palmitic, and stearic acids in the presence of adenosine 5′‐triphosphate, coenzyme A, and nicotinamide adenine dinucleotide, reduced form. The products of this reaction are the corresponding monoenoic fatty acids, myristoleic, palmitoleic, and oleic acids respectively. Desaturase, activity was greater with stearate as substrate than with either palmitate or myristate. Palmitate was desaturated at a rate ca. 50% greater than that of myristate. Although both nicotinamide adenine dinucleotide, reduced form and nicotinamide adenine dinucleotide phosphate, reduced form served as electron donors, the former was superior in this regard. Desaturase activity was not influenced by the addition of glycerol 3‐phosphate to the incubation medium. However, the presence of this compound did affect the type of lipid formed. In the absence of the added glyceride‐glycerol precursor, the major products were phospholipids, whereas in its presence they were triglycerides.
Effect of oxygen levels on the fatty acids and lipids ofMucor rouxii
Authors: Safe S. , Duncan J.
Published: December 2006

The effect of aerobic and oxygen limiting (anaerobic) growth conditions upon the fatty acid and lipid composition ofMucor rouxii has been examined. The aerobic cells contained a range of fatty acids typical of phycomycetes, i.e. γ‐linolenic acid, with an unsaturation index of 1.20, whereas the anerobic cells contained relatively high levels of shorter chained fatty acids and very low concentrations of unsaturated acids (unsaturation index=0.025). The unsaturated compounds were monoolefinic tetra‐, hexa‐, and octadecenoic acids; and closer examination of their di‐trimethylsilyl derivatives by gas chromatography and mass spectrometry showed that all three acids contained the double bond in the Δ9 position. These results were consistent with a microaerobic biosynthetic pathway. In addition, there were major quantitative differences in the lipid composition of the two types of cells; and it was evident that the differences in growth environment markedly affected the cellular lipid and fatty acid compositions.
Fractionation and analysis of fluorescent products of lipid peroxidation
Authors: Trombly Richard , Tappel Al
Published: December 2006

The fluorescence excitation spectrum of model conjugated Schiff base compounds that arise from the reaction of malonaldehyde with amino acids was shown to contain a maximum at 260–280 nm in addition to the previously observed maximum at 350–390 nm. Excitation at either maximum results in emission at a single maximum at 440–480 nm. The excitation and emission maxima of the model fluorescent compounds, together with the characteristic reductions in fluorescence intensity caused by alkaline pH or heavy metal coordination, provide criteria with which to examine lipid peroxidation products for the presence of the conjugated Schiff base fluorophore. Silicic acid column chromatography and silica gel thin layer chromatography were employed to fractionate the fluorescent products of model lipid peroxidation systems and of rat testicular lipid soluble extracts. These products contained large families of compounds whose fluorescence characteristics were the same as those of the Schiff base floorophores. The fractionation methods used enabled more thorough fluorescence characterization of many of the products of lipid peroxidation, but the fluores‐cence criteria available do not provide definitive proof of structure.
24‐Methylenelanost‐9(11)‐en‐3β‐ol, new triterpene alcohol from shea butter
Authors: Itoh T. , Tamura T. , Matsumoto T.
Published: December 2006

A new triterpene alcohol was isolated from shea butter and its structure was shown to be 24‐methylenelamost‐9(11)‐en‐3β‐ol. Gas chromatographic correlations between this triterpene alcohol and other related compounds are discussed.