bluuebunny/crossref_metadata_2025 huggingface dataset:
Tsunami waves generated by submarine landslides of variable volume: analytical solutions for a basin of variable depth
Authors: Didenkulova I. , Nikolkina I. , Pelinovsky E. , Zahibo N.
Published: November 2010

Abstract. Tsunami wave generation by submarine landslides of a variable volume in a basin of variable depth is studied within the shallow-water theory. The problem of landslide induced tsunami wave generation and propagation is studied analytically for two specific convex bottom profiles (h ~ x4/3 and h ~ x4). In these cases the basic equations can be reduced to the constant-coefficient wave equation with the forcing determined by the landslide motion. For certain conditions on the landslide characteristics (speed and volume per unit cross-section) the wave field can be described explicitly. It is represented by one forced wave propagating with the speed of the landslide and following its offshore direction, and two free waves propagating in opposite directions with the wave celerity. For the case of a near-resonant motion of the landslide along the power bottom profile h ~ xγ the dynamics of the waves propagating offshore is studied using the asymptotic approach. If the landslide is moving in the fully resonant regime the explicit formula for the amplitude of the wave can be derived. It is demonstrated that generally tsunami wave amplitude varies non-monotonically with distance.
Water masses and zonal current in the Western Tropical Atlantic in October 2007 and January 2008 (AMANDES project)
Authors: Silva A. C. , Grenier M. , Chuchla R. , Grelet J. , Roubaud F. , Hamelin B. , Lyard F. , Jeandel C.
Published: November 2010

Abstract. The properties and circulation of water masses are examined using data collected from a hydrographic and Acoustic Doppler Current profiler in the Western Tropical Atlantic during two cruises of the GEOTRACES process study "AMANDES" (AMazon-ANDEans): AMANDES I (October–November 2007) and AMANDES II (January 2008). In the upper layer (from the sea surface to 150 m) means of vertical sections of velocity are showing the structure of the Current (NBC) and North Equatorial Countercurrent. In the lower layer (below 150 m) the subsurface velocity core of the North Brazil UnderCurrent, Western Boundary Undercurrent (WBUC) and northern branch of the South Equatorial Current (nSEC) could be observed. In October the WBUC flows southeastward with a velocity of about 0.3 m s−1. In the studied area during October 2007, the NBUC and nSEC are transporting South Atlantic Central Water (SACW) from the Southern Hemisphere whereas the WBUC transports North Atlantic Central Water (NACW) southeastward. In the deep layers, the North Atlantic Deep Water (NADW) is composed of three components: the Upper North Atlantic Deep Water – UNADW (between 1310 and 1650 m), the Middle North Atlantic Deep Water (between 1930 and 2400 m), the Lower North Atlantic Deep Water (centered around 3430 m). Off Guyana, the Antartic Intermediate Water (AAIW) changes of composition between October 2007 (45.2% ACW, 32.2% AAIWsource and 22.6% UNADW) and January 2008 (62.4% ACW, 23.5% AAIWsource and 14.1% UNADW). These intermediate waters are significantly warmer, less oxygenated and saltier than their southern source, reflecting both oxygen consumption and mixing with the Atlantic Central Water (ACW) and the Upper North Atlantic Deep Water during their northward transit.
Cryogenic and non-cryogenic pool calcites indicating permafrost and non-permafrost periods: a case study from the Herbstlabyrinth-Advent Cave system (Germany)
Authors: Richter D. K. , Meissner P. , Immenhauser A. , Schulte U. , Dorsten I.
Published: November 2010

Abstract. Weichselian cryogenic calcites collected in what is referred to as the Rätselhalle of the Herbstlabyrinth-Advent Cave system are structurally classified as rhombohedral crystals and spherulitic aggregates. The carbon and oxygen isotopic composition of these precipitates (δ13C = +0.6 to −7.3‰ δ18O = −6.9 to −18.0‰) corresponds to those of known slowly precipitated cryogenic cave calcites under conditions of isotopic equilibrium between water and ice of Central European caves. The carbon and oxygen isotopic composition varies between different caves which is attributed to the effects of cave air ventilation before the freezing started. By petrographic and geochemical comparisons of Weichselian cryogenic calcite with recent to sub-recent precipitates as well as Weichselian non-cryogenic calcites of the same locality, a model for the precipitation of these calcites is proposed. While the recent and sub-recent pool-calcites isotopically match the composition of interglacial speleothems (stalagmites, etc.), isotope ratios of Weichselian non-cryogenic pool-calcites reflect cooler conditions. Weichselian cryogenic calcites show a trend towards low δ18O values with higher carbon isotope ratios reflecting slow freezing of the precipitating solution. In essence, the isotope geochemistry of the Weichselian calcites reflects the climate history changing from overall initial permafrost conditions to permafrost-free and subsequently to renewed permafrost conditions. Judging from the data compiled here, the last permafrost stage in the Rätselhalle is followed by a warm period (interstadial and/or Holocene). During this warmer period, the cave ice melted and cryogenic and non-cryogenic Weichselian calcite precipitates were deposited on the cave ground or on fallen blocks, respectively.
Brief communication "Application of mobile laser scanning in snow cover profiling"
Authors: Kaasalainen S. , Kaartinen H. , Kukko A. , Anttila K. , Krooks A.
Published: November 2010

Abstract. We present a snowmobile based mobile mapping system and its first application on snow cover roughness and change detection measurement. The ROAMER mobile mapping system, constructed at the Finnish Geodetic Institute, consists of the positioning and navigating systems, a terrestrial laser scanner, and the carrying platform (a snowmobile sledge in this application). We demonstrate the applicability of the instrument in snow cover roughness profiling and change detection by presenting preliminary results from a mobile laser scanning (MLS) campaign. The results show the potential of MLS for fast and efficient snow profiling from large areas in a millimetre scale.
Initial evaluation of an ultrasound measure for assessing the activity of skin lesions in juvenile localized scleroderma
Authors: Li S. C. , Liebling M. S. , Haines K. A. , Weiss J. E. , Prann A.
Published: November 2010

Objective

To evaluate the construct validity of 2 proposed measures (the Ultrasound Disease Activity [U‐DA] and the Tissue Thickness Score [TTS]) for evaluating sonographic differences in juvenile localized scleroderma skin lesions.

Methods

We conducted a retrospective review of juvenile localized scleroderma patients who had ultrasound scans of their skin lesions between October 2005 and February 2009. Imaged lesions were classified as active or inactive based upon clinical assessment. Lesions had to have been imaged within 1 month of a clinic visit or have the same clinical assessment during both the visit before and the visit after the scan. Two physicians scored the scans using the U‐DA, which scores for differences in lesion echogenicity and vascularity compared with normal tissue. Tissue thickness differences were evaluated by percent differences and by using the TTS. Wilcoxon's rank sum test was performed to assess differences.

Results

We studied 52 scans from 21 patients, 32 scans of active skin lesions and 20 scans of inactive skin lesions. Features reported by clinicians as indicative of active disease included erythema, warmth, violaceous color, new lesion, expansion of lesion, and induration. The U‐DA was significantly different between active and inactive skin lesions (P = 0.0010) with significant differences found for the parameters of total echogenicity, hypodermis echogenicity, and deep tissue layer vascularity (P = 0.0014, P = 0.0023, and P = 0.0374, respectively). No significant differences were found for tissue layer thickness or TTS.

Conclusion

The U‐DA may be a useful tool in the identification of localized scleroderma activity. Further study is needed to prospectively evaluate the validity, reliability, and sensitivity of this potential monitoring tool.
Role of magnetic resonance imaging in the diagnosis and prognosis of rheumatoid arthritis
Authors: Suter Lisa G. , Fraenkel Liana , Braithwaite R. Scott
Published: November 2010

Objective

To systematically evaluate the literature addressing the role of magnetic resonance imaging (MRI) in the diagnosis and prognosis of early undifferentiated inflammatory arthritis and rheumatoid arthritis (RA).

Methods

We performed a systematic literature review of the performance characteristics of MRI for diagnosing and prognosticating RA. We searched Ovid, supplementing this with manual searches of bibliographies, journals, meeting proceedings, and the ClinicalTrials.gov web site. To identify diagnostic studies, we included studies of any duration that prospectively examined whether MRI findings predicted RA diagnosis and reported adequate information to calculate sensitivity and specificity. To identify prognostic studies, we included prospective studies with at least a 12‐month followup period that measured both baseline MRI findings and clinical and/or radiographic outcomes.

Results

For diagnostic studies (n = 11), sensitivity and specificity of MRI findings for RA diagnosis ranged from 20–100% and 0–100%, respectively, depending upon the criteria used. Diagnostic performance of MRI improved when lower‐quality studies or studies with longer disease duration were excluded. For prognostic studies (n = 17), MRI findings did not predict clinical remission, and the ability to predict radiographic progression varied significantly (range 18–100% for sensitivity and 5.9–97% for specificity). Restricting the analysis to specific MRI findings or earlier disease improved MRI prognostic performance. The only prognostic study reporting 100% of a priori quality criteria found MRI bone edema to be the strongest predictor of radiographic progression.

Conclusion

Data evaluating MRI for the diagnosis and prognosis of early RA are currently inadequate to justify widespread use of this technology for these purposes, although MRI bone edema may be predictive of progression in certain RA populations.
Intentional and unintentional treatment nonadherence in patients with systemic lupus erythematosus
Authors: Daleboudt Gabriëlle M. N. , Broadbent Elizabeth , McQueen Fiona , Kaptein Ad A.
Published: November 2010

Objective

Patients may be defined as nonadherent if they do not take their medications as prescribed by their physicians. Determinants of nonadherence may vary between and within patient groups. This study investigated the extent to which patients with systemic lupus erythematosus (SLE) show intentional and unintentional nonadherence, and the associations of nonadherence with psychological and medical parameters.

Methods

The study included 106 patients who were receiving at least one immunosuppressive agent to control their SLE. Level of self‐reported adherence and a measure of both intentional and unintentional nonadherence were obtained. Questionnaires were completed to assess associations between adherence and problems with cognitive functioning, beliefs about medicines, illness perceptions, emotional health, and disease characteristics.

Results

The mean self‐reported adherence rate for the total patient group was 86.7%. At least occasional intentional nonadherence was reported by 46.2% of patients and 58.5% of patients were at least occasionally unintentionally nonadherent. Problems with cognitive functioning, concerns about adverse effects of medication, and younger age were the strongest predictors of (non)adherence. Patients who were emotionally affected by their SLE were more likely to report low adherence, but this was not a significant predictor after accounting for other variables. Disease characteristics showed no relationship to measures of adherence.

Conclusion

Although SLE patients reported high levels of adherence on average, they commonly reported intentional and unintentional nonadherence. Adherence was associated with both cognitions and emotions. Nonadherence may be reduced by targeting emotional and cognitive functioning and by fine tuning doctor–patient communication to address patients' individual concerns about their medications.
Natural history of radiographic hip osteoarthritis: A retrospective cohort study with 11–28 years of followup
Authors: Franklin Jonas , Ingvarsson Thorvaldur , Englund Martin , Ingimarsson Olafur , Robertsson Otto , Lohmander L. Stefan
Published: November 2010

Objective

To evaluate the association between radiographic hip osteoarthritis (OA) and future total hip replacement (THR) due to OA or hip fracture.

Methods

We studied a cohort of individuals who had colon radiography from 1980–1997. Minimal joint space (MJS) was measured and each hip was graded for radiographic OA according to the Kellgren/Lawrence scale. Subjects were followed until the end of 2008. A Cox proportional hazards model, adjusted for age and sex, was used to evaluate factors associated with THR and hip fracture.

Results

A total of 2,953 hips were studied (57% women). The cumulative incidence of THR was 2.5% and the cumulative incidence of hip fracture was 2.6%. For hips with radiographic hip OA (MJS of 2.5 mm or less), the cumulative incidence of THR was 16.9% and the hazard ratio (HR) for THR was 13.2 (95% confidence interval [95% CI] 8.1–21). Using Kellgren/Lawrence grading, the HR for THR was 12.9 (95% CI 7.9–21) for hips with radiographic OA compared to those without. The HR for all types of hip fracture for hips with radiographic OA (MJS of 2.5 mm or less) was 0.47 (95% CI 0.15–1.5), for intracapsular fractures was 0.29 (95% CI 0.04–2.1), and for extracapsular fractures was 0.67 (95% CI 0.16–2.8).

Conclusion

The risk of THR due to OA is substantially increased in patients with radiographic hip OA, regardless of symptoms, and increases with decreasing MJS. However, 11–28 years after having had radiographic hip OA, more than 4 of 5 of those having radiographic signs of hip OA had not had a THR for OA.
Pushing the Functionality of Diamond Nanoparticles to New Horizons: Orthogonally Functionalized Nanodiamond Using Click Chemistry
Authors: Meinhardt Thomas , Lang Daniel , Dill Holger , Krueger Anke
Published: November 2010

Click chemistry is one of the most versatile means for the efficient grafting of larger units such as fluorescence labels or biomolecules onto the surface of nanoparticles. Here, a first study on the applicability of different strategies for the copper‐catalyzed azide–alkyne coupling of diamond nanoparticles and organic moieties is reported. Both thermally annealed nanodiamond and mechanically pretreated diamond nanoparticles of different origin can be modified with moieties carrying either azide or alkyne groups. Several organic units have been efficiently “clicked” onto these particles. The method is then applied for the bifunctional surface modification of nanodiamond leading to a material exhibiting carboxylic and alkyne groups at the same time. These can be addressed by orthogonal coupling linkers. A model material carrying two distinct fluorescent dyes is produced this way and shows the characteristic luminescence of both dyes. The findings open the way for the application of nanodiamond as multifunctional labels, drug delivery vehicles, and targeting agents in biomedical applications.
A Small Molecule Non‐fullerene Electron Acceptor for Organic Solar Cells
Authors: Schwenn Paul E. , Gui Ke , Nardes Alexandre M. , Krueger Karsten B. , Lee Kwan H. , Mutkins Karyn , Rubinstein‐Dunlop Halina , Shaw Paul E. , Kopidakis Nikos , Burn Paul L. , Meredith Paul
Published: November 2010

Organic bulk heterojunction photovoltaic devices predominantly use the fullerene derivatives [C60]PCBM and [C70]PCBM as the electron accepting component. This report presents a new organic electron accepting small molecule 2‐[{7‐(9,9‐di‐n‐propyl‐9H‐fluoren‐2‐yl)benzo[c][1,2,5]thiadiazol‐4‐yl}methylene]malononitrile (K12) for organic solar cell applications. It can be processed by evaporation under vacuum or by solution processing to give amorphous thin films and can be annealed at a modest temperature to give films with much greater order and enhanced charge transport properties. The molecule can efficiently quench the photoluminescence of the donor polymer poly(3‐n‐hexylthiophene‐2,5‐diyl) (P3HT) and time resolved microwave conductivity measurements show that mobile charges are generated indicating that a truly charge separated state is formed. The power conversion efficiencies of the photovoltaic devices are found to depend strongly on the acceptor packing. Optimized K12:P3HT bulk heterojunction devices have efficiencies of 0.73±0.01% under AM1.5G simulated sunlight. The efficiencies of the devices are limited by the level of crystallinity and nanoscale morphology that was achievable in the blend with P3HT.
The evolution of the meningeal vascular system in the human genus: From brain shape to thermoregulation
Authors: Bruner Emiliano , Mantini Simone , Musso Fabio , De La Cuétara José Manuel , Ripani Maurizio , Sherkat Shahram
Published: November 2010

Objectives:

The imprints of the middle meningeal vessels make it possible to analyze vascularization in fossil specimens. The association between changes in the cortical anatomy and vascular organization raises questions about the actual physiological meaning of these features, most of all when dealing with the origin of the modern human brain. Metabolism and thermoregulation may be relevant factors in influencing morphological adaptations between brain and vessels. This study is aimed at investigating the relationships between endocranial morphology and endocranial vessels in modern humans and to analyze the pattern of heat dissipation through the endocranial surface in fossil specimens.

Methods:

Through angiotomography, it is possible to make an anatomical reconstruction of the meningeal and cerebral vessels, providing information on the morphology of the endocranial vascular system. At the same time, digital modeling can be performed to investigate the relationships between the endocranial geometry and physical properties such as heat dissipation patterns in extinct hominids.

Results:

The middle meningeal network is largely independent from the cerebral vascular system. Furthermore, in adults, the medium and upper tracts of the middle meningeal artery shows scarce or absent blood flow. Parietal bossing in modern humans involves relative cooling of the cortical surface at the supramarginal gyrus.

Conclusions:

The evidence does not support a thermoregulatory role for the meningeal vascular network, at least in adult normal blood flow conditions. On the other hand, biomechanical protective functions (hydraulic skeleton for shock adsorption) cannot be ruled out. Am. J. Hum. Biol., 2011. © 2010 Wiley‐Liss, Inc.
Heritability estimates for psychotic symptom dimensions in twins with psychotic disorders
Authors: Rijsdijk Frühling V. , Gottesman Irving I. , McGuffin Peter , Cardno Alastair G.
Published: November 2010

Factor analysis of psychotic symptoms frequently results in positive, negative, and disorganized dimensions, but heritability estimates have not yet been reported. Symptom dimensions are usually only measured in individuals with psychotic disorders. Here, it is valuable to assess influences acting via liability to psychosis and independent modifying effects. We estimated heritability for psychotic symptom dimensions, taking account of these issues. Two‐hundred‐and‐twenty‐four probandwise twin pairs (106 monozygotic, 118 same‐sex dizygotic), where probands had psychoses, were ascertained from the Maudsley Twin Register in London (1948–1993). Lifetime history of DSM‐III‐R psychotic disorder and psychotic symptom dimensions was assessed from clinical records and research interviews and rated using the Operational Criteria Checklist. Estimates of heritability and environmental components of variance in liability were made with structural equation modeling using a causal‐contingent common pathway model adapted for ascertainment from a clinical register. Significant heritability was found for DSM‐III‐R psychotic disorder (h2 = 90%, 95%CI 68–94%) and the disorganized symptom dimension (h2 = 84%, 95%CI 18–93%). The heritability for the disorganized dimension remained significant when influences acting through liability to psychosis were set to zero, suggesting that some influences on disorganization are modifying factors independent of psychosis liability. However, the relative extent of modifying factors versus influences acting through psychosis liability could not be clearly determined. To our knowledge, this study provides the first formal evidence of substantive heritability for the disorganized symptom dimension, and suggests that genetic loci influencing disorganization in individuals with psychoses are in some cases different from loci that influence risk of psychotic disorders themselves. © 2010 Wiley‐Liss, Inc.
Synthesis and characterization of polysiloxanes with pendant bicyclic fragments
Authors: Mukbaniani O. , Tatrishvili T. , Titvinidze G. , Patsatsia S.
Published: November 2010

The hydrosilylation reactions of 5‐vinyl‐2‐norbornene with α,ω‐bis(trimethylsiloxy)methylhydrosiloxane catalyzed by platinum hydrochloric acid (0.1Msolution in tetrahydrofuran), Karstedt's catalyst (Pt2[(VinSiMe2)2O]3) and platinum on the carbon have been studied. Dependence of reaction rate and active SiH bonds' conversion depth on the catalyst was investigated. Even in the excess of the 5‐vinyl‐2‐norbornene, not all active SiH groups participate in the hydrosilylation reaction. The reaction order, activation energies, and rate constants have been determined for hydrosilylation reactions in the presence of H2PtCl6. The synthesized oligomers were characterized by Fourier transform infrared spectroscopy (FTIR),1H,13C,1H‐1H correlation spectroscopy (COSY), and C,H‐correlation NMR spectroscopy. Synthesized polysiloxanes were characterized by wide‐angle X‐ray, gel‐permeation chromatography, and DSC analyses. Calculations using the quantum‐chemical semi‐empirical AM1 method for modeling reaction between methyldimethoxysilane [Me(MeO)2SiH] and 5‐vinyl‐2‐norbornene were performed to evaluate possible reaction paths. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Chemical grafting of curcumin at polyethylene terephthalate woven fabric surface using a prior surface activation with ultraviolet excimer lamp
Authors: Kerkeni A. , Gupta D. , Perwuelz A. , Behary N.
Published: November 2010

Durable curcumin‐treated antibacterial polyethylene terephthalate (PET) fabrics (against Staphylococcus aureus) were produced by dyeing with curcumin after surface activation using vacuum ultraviolet excimer lamp at 172 nm. Surface change properties of the exposed fabrics were characterized by surface analysis methods such as wettability, atomic force microscopy, and X‐ray photoelectron spectroscopy. Results show an increase in surface hydrophilicity with a water contact angle of the PET fabric reaching 24° after 10 min excimer irradiation, which could be attributed to an increase in carboxyl group formation as confirmed by X‐ray photoelectron spectroscopy measurements. Varying concentrations of curcumin were immobilized onto untreated and vacuum ultraviolet‐irradiated PET samples using diffusion method at 90°C, and the treated fabrics characterized using K/S (color strength) values at 440 nm. K/S values increased when the PET surface was subjected to a prior excimer irradiation, because of grafting of curcumin at the PET surface. Increased excimer irradiation time increased grafting of curcumin because the inner fabric fiber surfaces were also more thoroughly treated. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Using osteoclast differentiation as a model for gene discovery in an undergraduate cell biology laboratory
Authors: Birnbaum Mark J. , Picco Jenna , Clements Meghan , Witwicka Hanna , Yang Meiheng , Hoey Margaret T. , Odgren Paul R.
Published: November 2010

A key goal of molecular/cell biology/biotechnology is to identify essential genes in virtually every physiological process to uncover basic mechanisms of cell function and to establish potential targets of drug therapy combating human disease. This article describes a semester‐long, project‐oriented molecular/cellular/biotechnology laboratory providing students, within a framework of bone cell biology, with a modern approach to gene discovery. Students are introduced to the topics of bone cells, bone synthesis, bone resorption, and osteoporosis. They then review the theory of microchip gene arrays, and study microchip array data generated during the differentiation of bone‐resorbing osteoclasts in vitro. The class selects genes whose expression increases during osteoclastogenesis, and researches them in small groups using web‐based bioinformatics tools. Students then go to a biotechnology company website to find and order small inhibitory RNAs (siRNAs) designed to “knockdown” expression of the gene of interest. Students then learn to transfect these siRNAs into osteoclasts, stimulate the cells to differentiate, assay osteoclast differentiation in vitro, and measure specific gene expression using real‐time PCR and immunoblotting. Specific siRNA knockdown resulting in a decrease in osteoclastogenesis is indicative of a gene's physiological relevance. The results are analyzed statistically and presented to the class in groups. In the past 2 years, students identified several genes essential for optimal osteoclast differentiation, including Myo1d. The students hypothesize that the myo1d protein functions in osteoclasts to deliver important proteins to the cell surface via vesicular transport along microfilaments. Student response to the new course was overwhelmingly positive. Biochemistry and Molecular Biology Education Vol. 38, No. 6, pp. 385‐392, 2010
Surface‐Initiated Atom‐Transfer Radical Polymerization of 4‐Acetoxystyrene for Immunosensing
Authors: Yuan Liang , Wu Yafeng , Shi Hongyan , Liu Songqin
Published: November 2010

A novel immunosensing strategy based on surface‐initiated atom‐transfer radical polymerization (SI‐ATRP) in combination with electrochemical detection is proposed. Specifically, 4‐acetoxystyrene (AS) has been chosen as a monomer for ATRP due to its ability to provide acetoxyl groups, which can be converted into phenolic hydroxyl groups for electrochemical detection in the presence of tyrosinase. A controlled radical polymerization reaction of 4‐acetoxystyrene at 60 °C was triggered after immobilization of initiator molecules on an electrode surface. The growth of long‐chain polymeric materials increased the concentration of phenolic hydroxyl groups, which in turn significantly enhanced the electrochemical signal output. Polymerization conditions, such as temperature and duration, monomer concentration, and the catalyst/monomer ratio have been optimized. The in situ surface‐initiated ATRP was confirmed by scanning electron microscope (SEM) images and X‐ray photoelectron spectroscopy (XPS) analysis. Cyclic voltammetric investigation revealed a pair of well‐defined oxidation and reduction peaks at 0.232 and 0.055 V, which corresponded to the redox behavior of catechol/o‐quinone on the electrode surface. The proposed approach has been successfully extended to immune recognition. A detection limit of 0.3 ng mL−1 for rabbit immunoglobulin G (IgG) as a model antigen has been achieved. Despite the limited availability of the IgG antibody, this technology might also be expanded to the detection of other proteins and DNA.
Molecular Dynamics Simulations of a β‐Hairpin Fragment of Protein G by Means of Atom‐Bond Electronegativity Equalization Method Fused into Molecular Mechanics (ABEEMδπ/MM)
Authors: Chen Shuling , Yang Zhongzhi
Published: November 2010

There are some controversial opinions about the origin of folding β‐hairpin stability in aqueous solution. In this study, the structural and dynamic behavior of a 16‐residue β‐hairpin from B1 domain of protein G has been investigated at 280, 300, 350 and 450 K using molecular dynamics (MD) simulations by means of Atom‐Bond Electronegativity Equalization Method Fused into Molecular Mechanics i.e., ABEEMδπ/MM and the explicit ABEEM‐7P water solvent model. In addition, a 300 K simulation of one mutant having the aromatic residues substituted with alanines has been performed. The hydrophobic surface area, hydrophilic surface area and some structural properties have been used to measure the role of the hydrophobic interactions. It is found that the aromatic residues substituted with alanines have shown an evident destabilization of the structure and unfolding started after 1.5 ns. It is also found that the number of the main chain hydrogen bonds have different distributions through three different simulations. All above demonstrate that the hydrophobic interactions and the main chain hydrogen bonds play an important role in the stability of the folding structure of β‐hairpin in solution. Furthermore, through the structural analyses of the β‐hairpin structures from four temperature simulations and the comparison with other MD simulations of β‐hairpin peptides, the new ABEEMδπ force field can reproduce the structural data in good agreement with the experimental data.
Efficient Procedure for Oxathioacetalization Using the Novel Ionic Liquid
Authors: Bao Shaohua , Chen Lu , Ji Yongjun , Yang Jianguo
Published: November 2010

The novel ionic liquid with multi‐SO3H groups has been synthesized through the simple procedure and its catalytic activity for the oxathioacetalization was investigated carefully at room temperature under solvent‐free condition. The results showed that the novel ionic liquid was very efficient for the reactions with the average yields over 90%. Mild reaction conditions, high yields, small amount of usage, operational simplicity, needless of any solvent, wide applicability, reusability and chemoselectivity are the key features of this methodology.
Effects of Acid and Base on the Inductive Efficiency of Oligonucleotide on the Vesicle Formation from Single‐Chained Cationic Surfactant
Authors: Guo Xia , Cui Bo
Published: November 2010

Recently, we reported for the first time that oligonucleotide could induce single‐chained cationic surfactant molecules to aggregate into vesicles and the facilitative efficiency of oligonucleotide on vesicle formation was dependent on its size and sequence. In the present paper, we will continue to study the effects of acid and base on the facilitative efficiency of oligonucleotide on vesicle formation. It is found that proton ions show little effect on the facilitative efficiency while hydroxide ions make it decreased. Moreover, the percentage of oligonucleotide involved in vesicle formation in basic solution is much lower than that in acidic solution (which is almost equal to that in water). Since the structures and properties of DNA/amphiphile complex are very important for its application as nonviral gene carrier, this study may provide some helpful information for gene therapy.
Effects of Aspartic Acid and Lysine on Thermodynamic Functions of SDS Micellization
Authors: Liu Tianqing , Li Jiajia
Published: November 2010

Aspartic acid and lysine can promote SDS micellization. The critical micellar concentration of SDS decreases with amino acid concentration, but first does and then increases with temperature. In SDS micellization, the change of standard Gibbs free energy is negative in SDS/H2O system with or without amino acid. With the increase of amino acid concentration, the changes of mole standard Gibbs free energy and enthalpy decrease, but the change of the system's entropy increases. The effect of lysine is more than that of aspartic acid on the thermodynamic functions.
An Organically Templated Copper Pentaborate with Infinite Metallo‐chains: [Cu(C3N2H4)4][Cu(CH3COO)2(C3N2H4)2(H2O)2][B5O6(OH)4]2
Authors: You Xiaoyan , Zhu Lixia , Sun Jia
Published: November 2010

A novel organically templated copper pentaborate, [Cu(C3N2H4)4][Cu(CH3COO)2(C3N2H4)2(H2O)2]‐ [B5O6(OH)4]2, was synthesized by hydrothermal reaction and characterized by elemental analysis, single‐crystal X‐ray diffraction, FT‐IR spectroscopy, Raman spectroscopy and TGA. The crystal structure of this compound consists of two copper‐centered polyhedra and two discrete [B5O6(OH)4]− pentaborate anions, which are linked together through intensive hydrogen bonding interactions, forming a 3D framework with large channels along c axis. The discrete pentaborate anions form infinite layers by hydrogen bonds. Moreover, the two crystallographically different octahedral coppers are connected by common oxygen atom to form an infinite chain.
Single‐microemulsion‐based Hydrothermal Approach to In(OH)3 and In2O3 Nanocubes
Authors: Li Yanfen , Jiang Junying , Ma Yujie , Fan Gaochao , Huang Zaiyin , Ban Chunxu , Qin Liu'ai
Published: November 2010

Well‐defined indium hydroxide [In(OH)3] nanocubes have been successfully prepared through a facile single‐microemulsion‐mediated hydrothermal process at a relatively low temperature. Calcination of the In(OH)3 precursor at 400°C in a furnace yielded In2O3 crystals with the same morphology. X‐ray diffraction (XRD), field‐emission scanning electron microscopy (FE‐SEM), and transmission electron microscopy (TEM) were used to characterize the samples. The effects of reaction parameters on the formation of nanostructures were also discussed, and the nucleation, aggregation and anisotropic growth mechanism was proposed. Room temperature photoluminescence (PL) spectra as well as the ultraviolet‐visible (UV‐vis) absorbance spectra were carried out on the In2O3 crystals to investigate their optical properties.
Tributylammonium Halochromates/silica Gel: Simple Reagents for Oxidative Coupling of Thiols to Symmetrical Disulfides
Authors: Mohammadi Mohammad Kazem , Ghammamy Shahriare , Zarrinabadi Soroush , Farjam Mohammad Hossein , Sabayan Behrang
Published: November 2010

New orange solid tributylammonium halochromates, (C4H9)3N+CrO3X−, TBAXC (X=F, Cl) are easily synthesized by the reaction of tributylammonium fluoride and chloride with CrO3 in a 1:1 molar ratio in the presence of HF and HCl. Tributylammonium halochromates(VI) are versatile reagent for the effective and selective oxidation of organic substrates. Silica gel supported TBAFC and TBACC are versatile reagents for the effective and selective oxidation of organic substrates, in particular, thiols, under mild conditions. Considerable improvements are observed in the presence of the absorbent, making the work‐up much more convenient.
Synthesis of Click‐Chelator via Cu(I)‐Catalyzed Alkyne‐Azide Cycloaddition
Authors: Fu Yang , Liu Yan , Fu Xiaoping , Zou Li , Li Hua , Li Ming , Chen Xingguo , Qin Jingui
Published: November 2010

The click‐ligands based on 1,2,3‐triazole and pyridine unit has been synthesized via Cu(I)‐catalyzed alkyne‐azide cycloaddition from corresponding organic azides and terminal alkynes. The ligand structure was characterized by NMR, IR and elemental analysis as well as single crystal diffractions. The single crystal structure of the complexes from two different ligands coordinating to Cu(II) and Co(II) ions indicated that the N(2) atom in 1,2,3‐triazole unit can act as an efficient donor to metals through the rational molecular design.
Amidation of Aryl Halides Catalyzed by the Efficient and Recyclable Cu2O Nanoparticles
Authors: Yao Zijian , Wei Xianwen
Published: November 2010

Cu2O nanoparticles/DMEDA (N,N′‐dimethylethylenediamine) was proved to be an efficient catalyst system for amidation of aryl halides under mild condition. This method displayed excellent selectivity and the catalyst was recyclable without loss of activity. The low cost, simple operation and excellent yields make this approach attractive for industrial applications.
Synthesis of Alkyl‐Aryl Ethers by Copper‐catalyzed Etherization Reactions of Aryl Fluorides with Tetraalkylammonium Bromides and H2O
Authors: Wang Feng , Tang Boxiao , Xie Yexiang , Li Jinheng
Published: November 2010

Synthesis of alkyl aryl ethers via copper‐catalyzed etherizations of electron‐deficient aryl fluorides with quaternary ammonium bromides and water has been developed. In the presence of Cu(OAc)2, POPh3 (L4) and Cs2CO3, a variety of electron‐deficient aryl fluorides underwent the reaction with quaternary ammonium bromides and H2O in moderate to good yields. The mechanism was also discussed.
An imageable retinoid acid derivative to detect human cancer xenografts and study therapeutic dosing to reduce its toxicity
Authors: Wang Wei , Qiu Xiuchun , Zhang Fujun , Sun Jin , Cameron Arlin G. , Wendt Juliet A. , Mawad Michel E. , Ke Shi
Published: November 2010

Developing agents with ‘seek, treat and see’ capability is critical for personalized molecular medicine. Those agents will specifically target the disease markers for diagnosis and apply the biologically effective dose for treatment. Retinoids regulate a multitude of biological processes. In addition, retinoic acid can reverse premalignancy, significantly decrease second primary tumors and provide a treatment benefit in head and neck, lung, esophagus, colon and bladder cancer. These data suggest that cancer cells can take up retinoids. Therefore, retinoids are potential tumor‐imaging agents. We developed near‐infrared (NIR)‐labeled retinoid agents to detect human cancers, visualize drug redistribution within the body, determine the optimal biological dose and reduce systemic toxicity. Our data demonstrate that the retinoid agent, but not the free dye, binds to the human tumor cells and is internalized, where it permits the imaging of human cancer xenografts. The high dose of retinoid agent is significantly associated with systemic toxicity. In summary, synthetic NIR‐labeled retinoid agents can be used to detect multiple human cancer xenografts as the agent is internalized by cancer cells. The binding of the agent to the tumor xenografts is dependent on the redistribution of the agent. Therapeutic agents labeled with reporters will interrogate tumor–drug interactions and permit analysis of biodistribution, pharmacokinetics and pharmacodynamics in real time. At the same time, we can apply the biologically effective dose for therapy, instead of the traditional maximum tolerated dose, to reduce systemic toxicity. Copyright © 2010 John Wiley & Sons, Ltd.
Early microglia activation in a mouse model of chronic glaucoma
Authors: Bosco Alejandra , Steele Michael R. , Vetter Monica L.
Published: November 2010

Changes in microglial cell activation and distribution are associated with neuronal decline in the central nervous system (CNS), particularly under pathological conditions. Activated microglia converge on the initial site of axonal degeneration in human glaucoma, yet their part in its pathophysiology remains unresolved. To begin with, it is unknown whether microglia activation precedes or is a late consequence of retinal ganglion cell (RGC) neurodegeneration. Here we address this critical element in DBA/2J (D2) mice, an established model of chronic inherited glaucoma, using as a control the congenic substrain DBA/2J Gpnmb+/SjJ (D2G), which is not affected by glaucoma. We analyzed the spatial distribution and timecourse of microglial changes in the retina, as well as within the proximal optic nerve prior to and throughout ages when neurodegeneration has been reported. Exclusively in D2 mice, we detected early microglia clustering in the inner central retina and unmyelinated optic nerve regions, with microglia activation peaking by 3 months of age. Between 5 and 8 months of age, activated microglia persisted and concentrated in the optic disc, but also localized to the retinal periphery. Collectively, our findings suggest microglia activation is an early alteration in the retina and optic nerve in D2 glaucoma, potentially contributing to disease onset or progression. Ultimately, detection of microglial activation may have value in early disease diagnosis, while modulation of microglial responses may alter disease progression. J. Comp. Neurol. 519:599–620, 2011. © 2010 Wiley‐Liss, Inc.
Neurogenic hippocampal targets of deep brain stimulation
Authors: Encinas Juan M. , Hamani Clement , Lozano Andres M. , Enikolopov Grigori
Published: November 2010

Deep brain stimulation (DBS) is being used to treat movement, neurological, and psychiatric disorders; recently it has been successfully applied to patients with treatment‐resistant depression or in minimally conscious state. In addition to its clinical importance, DBS presents a powerful approach to target specific neural circuits and determine the functional relationship between the components of these circuits. We examined the effect of high‐frequency stimulation of a crucial component of the limbic circuitry, the anterior thalamic nuclei (ATN), on the generation of new neurons in the dentate gyrus (DG) of the hippocampus, another component of the same circuitry. Adult hippocampal neurogenesis emerges as a strong correlate of antidepressant treatments; however, in most cases, the progenitor cell population targeted by a specific treatment is not known. Using reporter mouse lines designed to quantify changes in selected classes of neural progenitors, we found that high‐frequency stimulation of the ATN increases symmetric divisions of a defined class of neural progenitors in the DG; this effect is later manifested as an increased number of new neurons. The affected class of neural progenitors is also affected by the antidepressant fluoxetine (Prozac) and physical exercise (running). This indicates that neurogenic stimuli of different natures can converge on the same neurogenic target in the DG. Our results also suggest that hippocampal neurogenesis may be used as a sensitive indicator of the limbic circuitry activation induced by DBS. J. Comp. Neurol. 519:6–20, 2011. © 2010 Wiley‐Liss, Inc.
Synthesis, Internalization, Recycling, and Regulation of Peptide Hormone Receptors
Authors: Sealfon Stuart C.
Published: November 2010

The sections in this article are:

Classification of Peptide Receptors

Overview of Regulatory Mechanisms

Receptor Biosynthesis

Endocytotic Cycle

Receptor Sequestration

Sequestration Motifs and Domains

Receptor Regulation

Conclusions
Mammalian Gs‐Stimulated Adenylyl Cyclases
Authors: Weng Gezhi , Chen Yibang , Iyengar Ravi
Published: November 2010

The sections in this article are:

Cloning of Mammalian Isoforms

Tissue Distribution of Various Adenylyl Cyclases

Structure and Catalytic Site

Basal Activity

Regulation by Protein–Protein Interactions

Ca2+/Calmodulin

G Protein Subunits

Regulation by Small Molecules

P‐Site Ligands

Forskolin

Ca2+

Regulation by Protein Kinases

Protein Kinase A

Protein Kinase C

Calmodulin‐Kinase

Other Protein Kinases

Future Directions
Phospholipid‐Derived Second Messengers
Authors: Exton John H.
Published: November 2010

The sections in this article are:

Inositol Phospholipid Hydrolysis

Functional Significance

Phosphoinositide Phospholipases as Targets of Hormones and Growth Factors

Phosphatidylinositol 3,4,5‐Trisphosphate Synthesis

Phosphatidylinositol 3‐Kinases as Targets of Hormones and Growth Factors

Role of Phosphatidylinositol 3‐Kinase in Cell Function

Phosphatidylcholine Hydrolysis

Phosphatidylcholine Hydrolysis by Phospholipase D and Its Functional Significance

Phospholipase D as a Target of Hormones and Growth Factors

Agonist‐Stimulated Phosphatidylcholine Hydrolysis by Phospholipase C

Agonist‐Stimulated Phosphatidylcholine Hydrolysis by Phospholipase A2

Sphingomyelin Hydrolysis and Its Functional Significance
Targeted Delivery of Hormones to Tissues by Plasma Proteins
Authors: Pardridge William M.
Published: November 2010

The sections in this article are:

Organ Physiology of Solute Exchange Through Capillary Walls

Quantitation of Capillary Solute Transport: Kety‐Renkin‐Crone Equation

Capillary Geometry, Organ Blood Flow, and Capillary Transit Times

Capillary Membrane Permeability

Capillary Physiology of Steroid and Thyroid Hormone Transport

Plasma Protein–Binding Kinetics

Dissociation‐Limited Transport

Enhanced Dissociation Mechanism of Plasma Protein–Mediated Transport

Transcapillary Transport of Protein–Hormone Complex

Physiology‐Based Model of Cellular Bioavailable Hormone

Experimental Attempts to Measure Free Cellular Hormone

Molecular Physiology of Hormone‐Binding Plasma Proteins

Albumin

Prealbumin (Transthyretin)

Thyroid Hormone–Binding Globulin

Corticosteroid‐Binding Globulin

Sex Hormone–Binding Globulin

α1‐Acid Glycoprotein (Orosomucoid)
The Roles of Cytochromes P‐450 in the Regulation of Steroidogenesis
Authors: Hall Peter F.
Published: November 2010

The sections in this article are:

Properties of Cytochromes P‐450

Chemical Properties

Spectral Properties

The P‐450 Cycle

The Mechanism of P‐450 Enzyme Activity

Reduction of Cytochrome P‐450

Synthesis of Steroid Hormones

Nomenclature

Pathways to Steroid Hormones

Individual Cytochromes P‐450

C27Side‐Chain Cleavage P‐450

C21Side‐Chain Cleavage P‐450 (Hydroxylase/Lyase)

C21Hydroxylase

11β‐Hydroxylase and Aldehyde Synthetase

Aromatase

The Role of Membranes in the Actions of Cytochromes P‐450

The Steroidogenic Inner Mitochondrial Membrane

The Steroidogenic Endoplasmic Reticulum

Molecular Biology of Cytochromes P‐450

Cytochrome P‐450c27scc(CYPII)

Cytochrome P‐450 C21scc(17α‐hydroxylase) (CYP17)

Cytochrome P‐450 21‐Hydroxylase (CYP21)

Cytochrome P‐450 11β‐Hydroxylase (CYP11)

Aromatase (CYP19)
Insulin Gene Transcription: Factors Involved in Cell Type–Specific and Glucose‐Regulated Expression in Islet β Cells are Also Essential During Pancreatic Development
Authors: Stein Roland
Published: November 2010

The sections in this article are:

Insulin Gene Expression

Principal Factors Regulating Insulin Gene Transcription

C2 Element

Z‐Element Region

A Elements

C1/RIPE3b1 Element

E Element

Other Key Pancreatic Cell Transcriptional Regulators

Targeted Disruption of Insulin Transcriptional Activators

PDX‐1 in Pancreatic Islet and Exocrine Cell Development

Isl‐1, Pax‐6, Pax‐4, and BETA2/NeuroD in Islet Endocrine Cell Development

Other Transcription Factors Necessary for Islet Cell Development

Factors Regulatingpdx‐1Gene Transcription

New Perspectives
Biosynthesis of Insulin
Authors: Steiner Donald F. , Chan Shu Jin , Rubenstein Arthur H.
Published: November 2010

The sections in this article are:

Insulin: Properties and Structure

Biosynthesis of Insulin

Structure and Functions of Precursor Forms

Cell Biology

Mechanism of Proteolytic Conversion of Proinsulin to Insulin

Insulin Storage Vesicles

C Peptide, a Co‐secretory Product of the β Cell

Regulation of Insulin Biosynthesis

The Insulin Gene and its Defects

Mutations in the Insulin Gene

Defects in Insulin Biosynthesis

Prohormone Convertase Defects

Conclusion