bluuebunny/crossref_metadata_2025 huggingface dataset:
Nasopharyngeal Cancer in Sudan: Epidemiology, Clinical and Histological Characteristics
Authors: Abdullah Nazik E. , Adam Ameera A.M. , Khalifa Eman H. , Hassan Lamyaa A.M. EL , Ibrahim M.E. , Hamad K.M. , Hassan A.M. El
Published: February 2011

Objectives

To study the epidemiology, clinical features, staging, etiology and pathology of nasopharyngeal cancer in Sudan.

Study design

This is a retrospective study.

Setting

Ear, Nose and Throat Department Khartoum Teaching Hospital, Khartoum City, Sudan.

Subjects and methods

Patients suspected to have nasopharyngeal cancer were assessed during the period March 2004 to May 2010. Data from confirmed cases was obtained; it included clinical and epidemiological information.

Results

Three hundred and eighty five cases were studied. Bimodal age distribution of the disease was noted with two peaks, one at 15–19 years and one at 50–54 years. The male to female ratio was 2.6:1 and a distinct geographical distribution of the disease was noted, with clustering of cases in the towns of Dilling, Kadogli and the surrounding rural area of the Nuba Mountains. These areas in the Western States were reported to be of high background radiation due to naturally produced radioactive uranium. The Nuba tribe headed the list among other tribes, demonstrating a clear ethnic predilection. Sixty-eight cases presented at stage IV. There was a predominance of Type II (15.58%) and Type III (65.97%). Patients were treated by neoadjuvant chemoradiotherapy.

Conclusions

NPC is an important form of cancer in Sudan. Some tribes are significantly more affected than others. Patients present with advanced disease. Environmental and genetic factors need further studies. Screening at risk populations that aim at early diagnosis and management of patients is recommended.
Grassroots Campaign Trail Methods to Recruit for Clinical Trials: Recruitment Lessons Learned from Trail to Trial
Authors: Murphy Megan , Merenstein Daniel
Published: February 2011

Background

Literature reviews have identified recruitment as the single most challenging obstacle in conducting pediatric trials. This paper describes a paradigm shift in recruitment design, developed from experience with grassroots campaigns through the DRINK study (Decreasing the Rates of Illness in Kids). The objective of this study was to explain a new method for recruiting in clinical trials based on lessons learned from grassroots political campaigning.

Methods and Findings

The study described is a randomized controlled trial of 638 3–6 year olds from the Washington, DC Area. The design involved a comparison between new recruiting approaches modeled after grassroots campaigns and traditional techniques. Traditional techniques for the purpose of this paper are defined by the use of physician referral, mass media such as radio and television advertisements, along with posters in public places like the subway. Grassroots approaches alternatively developed and utilized community contacts and employed targeted small market media community. The main outcome measures were the percentage of budget used and the number of eligible participants recruited.

Conclusions

The results showed that the grassroots recruitment approach saved 30% of the budget, recruited 638 kids in 4 months and retained over 90% for the 90 day trial. New techniques need further exploration as community studies are stressed.
Choroidal Proteins Involved in Cerebrospinal Fluid Production may be Potential Drug Targets for Alzheimer's Disease Therapy
Authors: Wostyn Peter , Audenaert Kurt , De Deyn Peter Paul
Published: February 2011

Alzheimer's disease is known to be the most common form of dementia in the elderly. It is clinically characterized by impairment of cognitive functions, as well as changes in personality, behavioral disturbances and an impaired ability to perform activities of daily living. To date, there are no effective ways to cure or reverse the disease. Genetic studies of early-onset familial Alzheimer's disease cases revealed causative mutations in the genes encoding β-amyloid precursor protein and the γ-secretase-complex components presenilin-1 and presenilin-2, supporting an important role of β-amyloid in the pathogenesis of Alzheimer's disease. Compromised function of the choroid plexus and defective cerebrospinal fluid production and turnover, with diminished clearance of β-amyloid, may play an important role in late-onset forms of Alzheimer's disease. If reduced cerebrospinal fluid turnover is a risk factor for Alzheimer's disease, then therapeutic strategies to improve cerebrospinal fluid flow are reasonable. However, the role of deficient cerebrospinal fluid dynamics in Alzheimer's disease and the relevance of choroidal proteins as potential therapeutic targets to enhance cerebrospinal fluid turnover have received relatively little research attention. In this paper, we discuss several choroidal proteins, such as Na+-K+ ATPase, carbonic anhydrase, and aquaporin 1, that may be targets for pharmacological up-regulation of cerebrospinal fluid formation. The search for potentially beneficial drugs useful to ameliorate Alzheimer's disease by facilitating cerebrospinal fluid production and turnover may be an important area for future research. However, the ultimate utility of such modulators in the management of Alzheimer's disease remains to be determined. Here, we hypothesize that caffeine, the most commonly used psychoactive drug in the world, may be an attractive therapeutic candidate for treatment of Alzheimer's disease since long-term caffeine consumption may augment cerebrospinal fluid production. Other potential mechanisms of cognitive protection by caffeine have been suggested by recent studies.
Effect of litter size and sex in the birth weight of newborn kids and in the behaviour of primiparous goats before, during and after the parturition
Authors: Otal J. , Martínez M. , Quiles A. , Hevia M.L. , Ramírez A.
Published: February 2011

The objective of this study was to determine the effect of litter size (46 single birth and 32 double birth) and sex (44 male and 66 female) of newborn kids on the puerperal behaviour of primiparous Murciano-Granadina goats (N = 78). The highest frequencies were grunting, with 124.9 ± 166.5, and butting conspecific, with 7.0 ± 8.7. Frequencies of the remaining variables considered (standing, kicking, moving head and neck, licking their back and pawing the earth) were lower than 3.0. The majority of variables were significantly greater for single births than for twin births (P < 0.01). Goats that gave birth to twins spent more time lying down, and less time walking than those that gave birth to one kid (10.1 ± 6.7 min vs. 6.8 ± 7.0 min, P < 0.05 and 2.9 ± 1.1 min vs. 6.0 ± 5.5 min, P < 0.01, respectively). Parturition was longer and birth weight heavier for singleton than twin-born kids (64.5 ± 15.7 min vs. 41.9 ± 10.7 min and 2.9 ± 0.2 kg vs. 2.3 ± 0.1 kg, respectively). In conclusion, primiparous goats showed objective signs of discomfort that were more evident for singleton than twin birth kids.
Agronomic performance of barley cultivars in response to varying rates of swine slurry
Authors: Buckley K. E. , Therrien M. C. , Mohr R. M.
Published: February 2011

Buckley, K. E., Mohr, R. M. and Therrien, M. C. 2011. Agronomic performance of barley cultivars in response to varying rates of swine slurry. Can. J. Plant Sci. 91: 69–79. Selection of crop variety may address concerns of potential adverse effects of preplant manure slurry application on crop yield and quality due to nutrient availability and lack of precision in application rate. An experiment was conducted in two field locations in southern Manitoba to assess the impact of slurry rate on growth, yield and quality of three barley (Hordeum vulgare L.) cultivars (Harrington, Rosser, Stander). Treatments included three rates of swine slurry, an unfertilized check and an inorganic fertilizer treatment at the recommended N rate based on preseeding soil nutrient tests. While the current study demonstrated no significant difference in the grain yield response of barley cultivars to rates of slurry application, higher rates of swine slurry may have a negative effect on milling quality (percentage of plump kernels) depending on cultivar, but had little effect on other quality parameters such as test weight and 1000-kernel weight. The absence of cultivar×slurry interaction for grain and biomass yield at each field location in each year indicated that all cultivars responded similarly to increasing rates of manure slurry for these traits. Grain protein concentration for all cultivars was unaffected by slurry amendment except at the highest application rate.
Hermitian curvature flow
Authors: Streets Jeffrey , Tian Gang
Published: February 2011

We define a functional for Hermitian metrics using the curvature of the Chern connection. The Euler–Lagrange equation for this functional is an elliptic equation for Hermitian metrics. Solutions to this equation are related to Kähler–Einstein metrics, and are automatically Kähler–Einstein under certain conditions. Given this, a natural parabolic flow equation arises. We prove short time existence and regularity results for this flow, as well as stability for the flow near Kähler–Einstein metrics with negative or zero first Chern class.
Verification and Clarification of Patterns of Sensory Integrative Dysfunction
Authors: Mailloux Zoe , Mulligan Shelley , Roley Susanne Smith , Blanche Erna , Cermak Sharon , Coleman Gina Geppert , Bodison Stefanie , Lane Christianne Joy
Published: February 2011

Building on established relationships between the constructs of sensory integration in typical and special needs populations, in this retrospective study we examined patterns of sensory integrative dysfunction in 273 children ages 4–9 who had received occupational therapy evaluations in two private practice settings. Test results on the Sensory Integration and Praxis Tests, portions of the Sensory Processing Measure representing tactile overresponsiveness, and parent report of attention and activity level were included in the analyses. Exploratory factor analysis identified patterns similar to those found in early studies by Ayres (1965, 1966a, 1966b, 1969, 1972b, 1977, & 1989), namely Visuodyspraxia and Somatodyspraxia, Vestibular and Proprioceptive Bilateral Integration and Sequencing, Tactile and Visual Discrimination, and Tactile Defensiveness and Attention. Findings reinforce associations between constructs of sensory integration and assist with understanding sensory integration disorders that may affect childhood occupation. Limitations include the potential for subjective interpretation in factor analysis and inability to adjust measures available in charts in a retrospective research.
Effects of Therapy Cushions on Classroom Behaviors of Children With Autism Spectrum Disorder
Authors: Umeda Caroline , Deitz Jean
Published: February 2011

OBJECTIVE. We investigated the effects of therapy cushions on the in-seat and on-task behaviors of 2 kindergarten students with autism spectrum disorder during math activities.

METHOD. We used a single-subject A–B–A–B–C design across 2 male participants who used chairs during baseline phases (A) and cushions during intervention phases (B). We included a choice phase (C) to determine participant seating preferences. Social validity was addressed by assessing teacher and participant seating preferences. Data were graphed and visually analyzed for functionally relevant changes between phases.

RESULTS. No clinically relevant changes in the in-seat or on-task behaviors of either participant were observed with cushion use.

CONCLUSION. Therapy cushions may not impose sufficient postural demands or provide adequate sensory input to produce behavioral changes. Continued research in this area is needed.
Psychometric Study of the Occupational Self Assessment With Adolescents After Infectious Mononucleosis
Authors: Taylor Renee , Lee Sun Wook , Kramer Jessica , Shirashi Yukiko , Kielhofner Gary
Published: February 2011

We examined the psychometric characteristics of the Occupational Self Assessment (OSA), which measures clients’ perceptions of their own competence and the value they assign to occupations. Two hundred ninety-six adolescents with acute mononucleosis completed the OSA, the Fatigue Scale, the Checklist of Infectious Symptoms, the Child Health Questionnaire, and the Perceived Stress Scale. OSA items coalesced to capture the intended constructs; the rating scales functioned as intended. More than 90% of adolescents were validly measured. The OSA showed adequate sensitivity and was stable over time. OSA measure of competence was moderately associated with infectious symptoms, fatigue severity, health status, and stress, and the measure of values was not. Neither measure was associated with age, gender, or ethnicity. Finally, adolescents who had not recovered from mononucleosis after 12 mo showed lower competence scores yet attached the same value or importance to occupational participation as adolescents who had recovered.
Survey of Driving Evaluation and Rehabilitation Curricula in Occupational Therapy Programs
Authors: Yuen Hon K. , Burik Jerry K.
Published: February 2011

OBJECTIVE. Our purpose in this study was to examine the preclinical curricular content pertaining to driving evaluation and rehabilitation (DE/R) included in professional entry-level occupational therapy programs.

METHOD. An e-mail survey containing questions about the program’s structure and extent of course material related to DE/R in the curriculum was sent to directors of all 144 U.S. accredited professional entry-level occupational therapy programs.

RESULTS. Ninety programs responded (62.5% response rate), of which 80 included content related to DE/R in some required courses, and 9 programs offered a required course specifically in DE/R. Approximately 18% of the respondent programs offered electives with DE/R content.

CONCLUSION. Of the respondent professional entry-level occupational therapy programs, few offer a required course specifically devoted to DE/R, but almost all programs integrate DE/R content into required coursework, thus satisfying the Accreditation Council for Occupational Therapy Education standards related to driver rehabilitation.
Optical properties of elemental carbon and water-soluble organic carbon in Beijing, China
Authors: Cheng Y. , He K.-B. , Zheng M. , Duan F.-K. , Ma Y.-L. , Du Z.-Y. , Tan J.-H. , Liu J.-M. , Zhang X.-L. , Weber R. J. , Bergin M. H. , Russell A. G.
Published: February 2011

Abstract. The mass absorption cross-section (MAC) of elemental carbon (EC) in Beijing was quantified using a thermal-optical carbon analyzer and the influences of mixing state and sources of carbonaceous aerosol were investigated. The MAC measured at 632 nm was 29.0 and 32.0 m2 g−1 during winter and summer respectively. MAC correlated well with the organic carbon (OC) to EC ratio (R2 = 0.91) which includes important information about the extent of secondary organic aerosol (SOA) production, indicating the enhancement of MAC by coating with SOA. The extrapolated MAC value was 10.5 m2 g−1 when the OC to EC ratio is zero, which was 5.6 m2 g−1 after correction by the enhancement factor (1.87) caused by the artifacts associated with the "filter-based" methods. The MAC also increased with sulphate (R2 = 0.84) when the sulphate concentration was below 10 μg m−3, whereas MAC and sulphate were only weekly related when the sulphate concentration was above 10 μg m−3, indicating the MAC of EC was also enhanced by coating with sulphate. Based on a converting approach that accounts for the discrepancy caused by measurements methods of both light absorption and EC concentration, previously published MAC values were converted to the "equivalent MAC", which is the estimated value if using the same measurement methods as used in this study. The "equivalent MAC" was found to be much lower in the regions heavily impacted by biomass burning (e.g., India), probably due to the influence of brown carbon. Optical properties of water-soluble organic carbon (WSOC) in Beijing were also presented. Light absorption by WSOC exhibited strong wavelength (λ) dependence such that absorption varied approximately as λ−7, which was characteristic of the brown carbon spectra. The mass absorption efficiency (σabs) of WSOC (measured at 365 nm) was 1.83 and 0.70 m2 g−1 during winter and summer respectively. The seasonal pattern of σabs was attributed to the difference in the precursors of SOA, because WSOC in Beijing has been demonstrated to be strongly linked to SOA. Moreover, the σabs of WSOC in Beijing was much higher than results from the southeastern United States which were obtained using the same method as used in this study, perhaps due to the influence of biomass burning.
Climatology of GPS phase scintillation and HF radar backscatter for the high-latitude ionosphere under solar minimum conditions
Authors: Prikryl P. , Jayachandran P. T. , Mushini S. C. , Chadwick R.
Published: February 2011

Abstract. Maps of GPS phase scintillation at high latitudes have been constructed after the first two years of operation of the Canadian High Arctic Ionospheric Network (CHAIN) during the 2008–2009 solar minimum. CHAIN consists of ten dual-frequency receivers, configured to measure amplitude and phase scintillation from L1 GPS signals and ionospheric total electron content (TEC) from L1 and L2 GPS signals. Those ionospheric data have been mapped as a function of magnetic local time and geomagnetic latitude assuming ionospheric pierce points (IPPs) at 350 km. The mean TEC depletions are identified with the statistical high-latitude and mid-latitude troughs. Phase scintillation occurs predominantly in the nightside auroral oval and the ionospheric footprint of the cusp. The strongest phase scintillation is associated with auroral arc brightening and substorms or with perturbed cusp ionosphere. Auroral phase scintillation tends to be intermittent, localized and of short duration, while the dayside scintillation observed for individual satellites can stay continuously above a given threshold for several minutes and such scintillation patches persist over a large area of the cusp/cleft region sampled by different satellites for several hours. The seasonal variation of the phase scintillation occurrence also differs between the nightside auroral oval and the cusp. The auroral phase scintillation shows an expected semiannual oscillation with equinoctial maxima known to be associated with aurorae, while the cusp scintillation is dominated by an annual cycle maximizing in autumn-winter. These differences point to different irregularity production mechanisms: energetic electron precipitation into dynamic auroral arcs versus cusp ionospheric convection dynamics. Observations suggest anisotropy of scintillation-causing irregularities with stronger L-shell alignment of irregularities in the cusp while a significant component of field-aligned irregularities is found in the nightside auroral oval. Scintillation-causing irregularities can coexist with small-scale field-aligned irregularities resulting in HF radar backscatter. The statistical cusp and auroral oval are characterized by the occurrence of HF radar ionospheric backscatter and mean ground magnetic perturbations due to ionospheric currents.
Ionospheric variations before some large earthquakes over Sumatra
Authors: Hasbi A. M. , Mohd Ali M. A. , Misran N.
Published: February 2011

Abstract. The paper investigates the ionospheric variations before some large earthquakes that occurred during 2004–2007 in Sumatra using GPS and CHAMP data. The TEC shows the occurrence of positive and negative anomalies detected within a few hours to 6 days before the earthquakes. These anomalies mostly occur during the daytime hours between 4 and 17 LT. The TEC anomalies are mostly consistent with the CHAMP satellite electron density data. The electron density analysis over the 28 March 2005 earthquake epicenter shows that an equatorial anomaly modification took place a few days before the event. The modification took shape in the form of crest amplification during the daytime. The comparison between the TEC and electron density measurements during very quiet geomagnetic conditions is shown to be a useful indicator of a forthcoming earthquake.
Changes in the African monsoon region at medium‐term time horizon using 12 AR4 coupled models under the A1b emissions scenario
Authors: Fontaine Bernard , Roucou Pascal , Monerie Paul‐Arthur
Published: February 2011

This study documents simulated precipitation and circulation changes through the 20C3M and A1b scenarios. It portrays a robust pattern, associating rainfall deficits in subtropical regions with rainfall excesses over West Africa, except in Northern Senegal and Mauritania, with a significant enhancement of both the April–June rainy season in 10/12 models and of the July–September rainy season in 8/12 models. Eastward to 5°W a northward shift in the latitude of the moisture flux convergence at 850 hPa is evident in 10/11 models (+0.58° in mean) and a southward shift in 6/11 models in the western region (−0.24°) is observed. Copyright © 2011 Royal Meteorological Society
Contrasted land‐surface processes along the West African rainfall gradient
Authors: Séguis L. , Boulain N. , Cappelaere B. , Cohard J.M. , Favreau G. , Galle S. , Guyot A. , Hiernaux P. , Mougin É. , Peugeot C. , Ramier D. , Seghieri J. , Timouk F. , Demarez V. , Demarty J. , Descroix L. , Descloitres M. , Grippa M. , Guichard F. , Kamagaté B. , Kergoat L. , Lebel T. , Le Dantec V. , Le Lay M. , Massuel S. , Trichon V.
Published: February 2011

We review the main results of land‐surface studies obtained in the three sites of the long‐term observing system AMMA‐CATCH. Runoff in the Sahel enhances the variability of energy partitioning between non‐infiltrative areas where sensible heat is dominant and infiltrative areas where soil water availability increases the latent flux. In terms of water resources, an increase in runoff over the past 50 years, already reported for the exoreic Sahel, was revealed in the endoreic Sahel. In the Sudanian domain, the subsurface origin of streamflow could explain its decrease over the same period. Copyright © 2011 Royal Meteorological Society
Early warning systems for food security in West Africa: evolution, achievements and challenges
Authors: Genesio L. , Bacci M. , Baron C. , Diarra B. , Di Vecchia A. , Alhassane A. , Hassane I. , Ndiaye M. , Philippon N. , Tarchiani V. , Traoré S.
Published: February 2011

In West Africa, early warning systems (EWSs) for food security have been widely recognized to have contributed, in the last 20 years, to an improved ability to deal with famine emergencies. Nevertheless, despite the advancements in understanding of the environmental and socio‐economic dynamics and despite the improved technologies, tackling food security remains a difficult task for decision makers as demonstrated by local food crises in many countries of the region. African Monsoon Multidisciplinary Analysis, while improving the understanding of the monsoon system, allowed us to better orient research challenges to provide EWS with improved products, effectively meeting the needs of end‐users at different levels. Copyright © 2011 Royal Meteorological Society
An intensity‐based approach for equity modeling
Authors: Escobar M. , Friederich T. , Krayzler M. , Seco L. , Zagst R.
Published: February 2011

This paper analyzes an intensity‐based approach for equity modeling. We use the Cox–Ingersoll–Ross (CIR) process to describe the intensity of the firm's default process. The intensity is purposely linked to the assets of the firm and consequently is also used to explain the equity. We examine two different approaches to link assets and intensity and derive closed‐form expressions for the firms' equity under both models. We use the Kalman filter to estimate the parameters of the unobservable intensity process. We demonstrate our approach using historical equity time series data from Merrill Lynch. Copyright © 2011 John Wiley & Sons, Ltd.
The sweet connection: Solving the riddle of multiple sugar‐binding fimbrial adhesins in Escherichia coli
Authors: Korea Charalampia‐Georgia , Ghigo Jean‐Marc , Beloin Christophe
Published: February 2011

Proteinaceous stalks produced by Gram‐negative bacteria are often used to adhere to environmental surfaces. Among them, chaperone‐usher (CU) fimbriae adhesins, related to prototypical type 1 fimbriae, interact in highly specific ways with different ligands at different stages of bacterial infection or surface colonisation. Recent analyses revealed a large number of potential and often “cryptic” CU fimbriae homologues in the genome of commensal and pathogenic Escherichia coli and closely related bacteria. We propose that CU fimbriae form a yet unexplored arsenal of lectins, carbohydrate‐binding proteins involved in various aspects of bacterial surface adhesion and tissue tropism. Combined efforts of molecular and structural biologists will be required to unravel the biological contribution of the bacterial lectome, however, current progress has already opened up new perspectives in the design of novel anti‐infective strategies.
Integrating a 250 mL‐spinner flask with other stirred bench‐scale cell culture devices: A mass transfer perspective
Authors: Vallejos Jose R. , Brorson Kurt A. , Moreira Antonio R. , Rao Govind
Published: February 2011

The bioprocess development cycle is a complex task that requires a complete understanding of the engineering of the process (e.g., mass transfer, mixing, CO2 removal, process monitoring, and control) and its affect on cell biology and product quality. Despite their widespread use in bioprocess development, spinner flasks generally lack engineering characterization of critical physical parameters such as kLa, P/V, or mixing time. In this study, mass transfer characterization of a 250‐mL spinner flask using optical patch‐based sensors is presented. The results quantitatively show the effect of the impeller type, liquid filling volume, and agitation speed on the volumetric mass transfer coefficient (kLa) in a 250‐mL spinner flask, and how they can be manipulated to match mass transfer capability at large culture devices. Thus, process understanding in spinner flasks can be improved, and these devices can be seamlessly integrated in a rational scale‐up strategy from cell thawing to bench‐scale bioreactors (and beyond) in biomanufacturing. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011.
Effect of chemical chaperone addition on production and aggregation of recombinant flag‐tagged COMP‐angiopoietin 1 in chinese hamster ovary cells
Authors: Hwang Su‐Jeong , Jeon Choon‐Ju , Cho Sung Min , Lee Gyun Min , Yoon Sung Kwan
Published: February 2011

To investigate the effect of chemical chaperones on the production and aggregation of flag‐tagged cartilage oligomeric matrix protein‐Angiopoietin1 (FCA1) in recombinant Chinese hamster ovary (CHO) cells, CHO cells were cultivated in serum‐free media with various chemical chaperones, 1 mM 4‐phenylbutyrate (4‐PBA), 200 mM proline, 3% glycerol, 2% dimethyl sulfoxide (DMSO), and without chemical chaperone as control. The addition of chemical chaperones enhanced FCA1 production and specific FCA1 productivity, qFCA1. For example, the qFCA1 at 200 mM proline was fourfold higher than that at control. Unlike qFCA1, the aggregation of FCA1 was strongly affected by which chemical chaperone was added. The addition of 2% DMSO and 200 mM proline significantly reduced the proportion of aggregates, but the addition of 1 mM 4‐PBA and 3% glycerol was hardly effective. The proportions of aggregates were 29.5 and 55.6% at 2% DMSO and 200 mM proline, respectively, whereas it was 79.6% at control. The exact mechanism how chemical chaperones affected the aggregation of FCA1 was not investigated in this study, and therefore, more extensive works will be needed to clarify why different chemical chaperones behaved differently in reducing the aggregation of FCA1. Among chemical chaperones tested, DMSO was the most effective one in regard to enhancing the production and reducing the aggregation of FCA1 in CHO cells. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Peptide Mesocrystals as Templates to Create an Au Surface with Stronger Surface‐Enhanced Raman Spectroscopic Properties
Authors: Su Ying , He Qiang , Yan Xuehai , Fei Jinbo , Cui Yue , Li Junbai
Published: February 2011

The design and fabrication of various nanostructures with predefined geometry and composition is a big challenge of nanotechnology. Here we demonstrate an Au nanoflake film replicated from a self‐assembled, well‐ordered, dipeptide flower‐like hierarchical architecture. Such morphology can give rise to useful and remarkable surface‐enhanced Raman spectroscopy (SERS) properties. We obtained these nanostructures by using a scaffold of flake‐built spherical dipeptide aggregations. Gold nanoparticles were sputtered on the surface of as‐assembled dipeptide by an etching system. After removing the dipeptide templates by ethanol, a metal crust was left with a morphology similar to that of the dipeptide hierarchical structure. The different steps within the process were monitored by using electron microscopy, energy‐dispersive spectrum (EDS) analysis and atomic force microscopy (AFM). Cyclic voltammetry and Raman spectra were employed to prove the SERS effect of the obtained Au substrates. The enhancement factor is estimated to be about 104 for 4‐mercaptobenzoic acid (4‐MBA) molecules on the Au nanoflake surfaces.
Förster Energy Transfer Theory as Reflected in the Structures of Photosynthetic Light‐Harvesting Systems
Authors: Şener Melih , Strümpfer Johan , Hsin Jen , Chandler Danielle , Scheuring Simon , Hunter C. Neil , Schulten Klaus
Published: February 2011

Förster′s theory of resonant energy transfer underlies a fundamental process in nature, namely the harvesting of sunlight by photosynthetic life forms. The theoretical framework developed by Förster and others describes how electronic excitation migrates in the photosynthetic apparatus of plants, algae, and bacteria from light absorbing pigments to reaction centers where light energy is utilized for the eventual conversion into chemical energy. The demand for highest possible efficiency of light harvesting appears to have shaped the evolution of photosynthetic species from bacteria to plants which, despite a great variation in architecture, display common structural themes founded on the quantum physics of energy transfer as described first by Förster. Herein, Förster’s theory of excitation transfer is summarized, including recent extensions, and the relevance of the theory to photosynthetic systems as evolved in purple bacteria, cyanobacteria, and plants is demonstrated. Förster′s energy transfer formula, as used widely today in many fields of science, is also derived.
From Sir2008 to Sir2011: the role of electron diffraction
Authors: Camalli M. , Carrozzini B. , Cascarano G. L. , Giacovazzo C.
Published: February 2011

The crystal structure solution of small‐medium size molecules via single crystal X‐ray data is almost a routine process. When single crystals of sufficient dimensions are not available, electron diffraction is a useful alternative: the structure solution however may still be a challenge. We have modified the standard version of Sir2008 to include several new tools, which are expected to make the phasing process more straightforward. Additional work is in progress: in Sir2011, the heir of Sir2008, particular emphasis will be given to a new procedure for the determination of the space groups, to a new approach (BEA) aiming at reducing in the practice the perverse effects of the dynamical scattering and to the simulated annealing algorithm, as a phasing tool particularly useful in case of organic structures, when scarce or poor experimental data are available. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of ion beam sputtered ZrN coatings prepared at different substrate temperatures
Authors: Larijani M. M. , Kiani M. , Tanhayi M. , Majdabadi A.
Published: February 2011

Zirconium nitride (ZrN) coatings were prepared on Si (100) by single ion beam sputtering in N2 and Ar mixture at different substrate temperatures. Structure and morphology of the ZrN coatings were analyzed using X‐ray diffraction and atomic force microscopy. Rutherford backscattering technique was utilized for the determination of composition and thickness of the coatings. Electrical properties of the ZrN coatings were determined by four point‐ probe and Hall test. The results showed that the growth of ZrN with a preferred (111) orientation was achieved. The coating thickness depended on the substrate temperature and coating surface roughly remained smooth. The resistivity of the coatings varied from 1× 10‐3 to 14× 10‐3 Ω cm depending on the substrate temperature. A correlation between resistivity and charge carrier density was established to explain the electrical behavior of the coatings. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Efficacy and safety of the PPARγ partial agonist balaglitazone compared with pioglitazone and placebo: a phase III, randomized, parallel‐group study in patients with type 2 diabetes on stable insulin therapy
Authors: Henriksen Kim , Byrjalsen Inger , Qvist Per , Beck‐Nielsen Henning , Hansen Gitte , Riis Bente J. , Perrild Hans , Svendsen Ole Lander , Gram Jeppe , Karsdal Morten A. , Christiansen Claus ,   for the BALLET trial investigators
Published: February 2011

Background

Treatment of patients with perioxisome proliferator‐activated receptor‐γ full agonists are associated with weight gain, heart failure, peripheral oedema, and bone loss. However, the safety of partial perioxisome proliferator‐activated receptor‐γ agonists has not been established in a clinical trial. The BALaglitazone glucose Lowering Efficacy Trial aimed to establish the glucose‐lowering effects and safety parameters of the perioxisome proliferator‐activated receptor‐γ partial agonist balaglitazone in diabetic patients on stable insulin therapy.

Methods

Four hundred and nine subjects from three countries with type 2 diabetes on stable insulin therapy were randomized to 26 weeks of double‐blind treatment with once daily doses of 10 or 20 mg balaglitazone, 45 mg pioglitazone, or matching placebo (n ≥ 99 in each group). The primary endpoint was the efficacy of balaglitazone 10 and 20 mg versus placebo on the absolute change in haemoglobin A1c. Secondary endpoints included levels of fasting serum glucose, and changes in body composition and bone mineral density as measured by dual energy X‐ray absorptiometry, in comparison to pioglitazone 45 mg. This study is registered with Clinicaltrials.gov identifier: NCT00515632.

Results

In the 10‐ and 20‐mg balaglitazone groups, and in the 45‐mg pioglitazone group, significant reductions in haemoglobin A1c levels were observed (−0.99, − 1.11, and − 1.22%, respectively; p < 0.0001) versus placebo. Fasting serum glucose was similarly reduced in all treatment arms. Dual energy X‐ray absorptiometry analyses showed that, while balaglitazone at 10 mg caused weight gain and fluid retention compared to placebo, the magnitude of these effects was significantly smaller than that of pioglitazone 45 mg and balaglitazone 20mg. Balaglitazone at either dose did not appear to reduce bone mineral density, while Pioglitazone showed a trend towards a reduction.

Conclusion

Patients treated with balaglitazone at 10 mg and 20 mg and pioglitazone at 45 mg showed clinically meaningful improvements in glucose levels and HbA1c. With the 10 mg dose, the benefits (glucose & HgA1c lowering) and untoward effects (fluid and fat accumulation) were less, results that encourage further studies of this drug candidate. Copyright © 2011 John Wiley & Sons, Ltd.
Effects of retinoic acid and butyric acid on the expression of prestin and gata‐3 in organotypic cultures of the organ of corti of newborn rats
Authors: Gross Johann , Stute Kerstin , Fuchs Julia , Angerstein Maximilian , Amarjargal Nyamaa , Mazurek Birgit
Published: February 2011

Prestin is the motor protein of the outer hair cells of the organ of Corti and a key factor in ensuring a high level of sensitivity of mammalian hearing. The factors that influence prestin expression are still largely unknown. We studied the effects of the application of retinoic acid, a ligand of a nuclear receptor, and of butyric acid, an inhibitor of histone deacetylase activity, on the expression of mRNA of prestin and Gata‐3 in the organotypic culture of the organ of Corti of newborn rats using RT‐PCR. Application of retinoic acid at concentrations of 1–50 μM results in a dose‐dependent expression decrease after two days in culture. Treatment with sodium butyrate (0.5–2 mM) elevated the expression of prestin and Gata‐3. Statistically significant correlations between Gata‐3 and prestin mRNA levels were observed under all conditions. The data indicate that retinoid nuclear transcription factors, GATA‐3 and histone acetylation/deacetylation processes may have a regulatory role to play in prestin expression. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 71: 650–661, 2011
Differential weight restoration on olanzapine versus fluoxetine in identical twins with anorexia nervosa
Authors: Duvvuri Vikas , Cromley Taya , Klabunde Megan , Boutelle Kerri , Kaye Walter H.
Published: February 2011

Objective:

No studies have compared the response to selective serotonin reuptake inhibitors and atypical antipsychotics in anorexia nervosa. This case study examines such a comparison.

Method:

This report describes a case of 12‐year‐old identical twins with anorexia nervosa, one of whom was treated with olanzapine and the other with fluoxetine, while undergoing family therapy.

Results:

Twin A treated with fluoxetine went from 75 to 84.4% ideal body weight, while Twin B treated with olanzapine went from 72 to 99.9% ideal body weight over the course of 9 months.

Discussion:

This case supports the need for adequately powered, controlled clinical trials to test the efficacy of olanzapine in adolescents presenting with anorexia nervosa. © 2011 by Wiley Periodicals, Inc. (Int J Eat Disord 2012)
Electric field‐induced self‐assembly of micro‐ and nanoparticles of various shapes at two‐fluid interfaces
Authors: Janjua Muhammad , Nudurupati Sai , Singh Pushpendra , Aubry Nadine
Published: February 2011

Particle lithography which explores the capability of particles to self‐assemble offers an attractive means to manufacture nanostructured materials. Although traditional techniques typically lead to the formation of dense crystals, adjustable non‐close‐packed crystals are crucial in a number of applications. We have recently proposed a novel method to assemble spherical micro‐ and nanoparticles into monolayers. The technique consists of trapping particles at a liquid–fluid interface and applying an electric field normal to the interface. Particles rearrange themselves under the influence of interfacial and electrostatic forces to form 2‐D hexagonal arrays of long‐range order and whose lattice constant depends on the electric field strength and frequency. Furthermore, the existence of an electric field‐induced capillary force makes the technique applicable to submicron and nanosized particles. Although spherical particles are often used, non‐spherical particles can be beneficial in practice. Here, we review the method, discuss its applicability to particles of various shapes, and present results for particles self‐assembly on air–liquid and liquid–liquid interfaces. In the case of non‐spherical particles, the self‐assembly process, while still taking place, is more complex as particles experience a torque which causes them to rotate relative to one another. This leads to a final arrangement displaying either a dominant orientation or no well‐defined orientation. We also discuss the possibility of dislodging the particles from the interface by applying a strong electric field such that the Weber number is of order 1 or larger, a phenomenon which can be utilized to clean particles from liquid–fluid surfaces.
Insight into the mechanism of transient trapping in micellar electrokinetic chromatography
Authors: Breadmore Michael C. , Quirino Joselito P. , Thormann Wolfgang
Published: February 2011

Transient trapping is a new mechanism of on‐line sample concentration and separation that has recently been presented. It involves the injection of a short length of micellar solution in front of the sample, making it similar to sweeping in partial‐filling MEKC. Here, we examine the mechanism of transient trapping by the use of computer simulations and compare it to sweeping in MEKC for the two analytes, sulforhodamine B and 101. The simulation results confirm the mechanism for concentration and separation originally proposed. The mechanism for concentration is similar to sweeping since the analytes are picked and accumulated by the micelles that penetrate the sample zone. The mechanism for separation is however quite unique since the concentrated analytes are trapped for a few seconds on the sample/micelle boundary before they are released as the concentration of micelle is reduced as it undergoes electromigration dispersion and the analytes separate down a micelle gradient. Simulation results suggested that a significant contribution of band broadening arises from the micelle gradient, with shallower gradients resulting in broader peaks. However, this is offset by an increase in selectivity, such that resolution was enhanced even though the peaks are broader. Transient trapping analysis with similar resolution to those obtained by sweeping MEKC could be achieved in 1/10 of the time and 1/4 of the capillary length, which results in a 2–3 times increase in sensitivity.
A simplified poly(dimethylsiloxane) capillary electrophoresis microchip integrated with a low‐noise contactless conductivity detector
Authors: Liu Benyan , Zhang Yi , Mayer Dirk , Krause Hans‐Joachim , Jin Qinghui , Zhao Jianlong , Offenhäusser Andreas
Published: February 2011

A contactless conductivity detector integrated into a poly(dimethylsiloxane) microchip for electrophoresis is presented. It adopted the simplest configuration of electrodes commonly used in this detection mode for capillary electrophoresis microchips. Although the chip is based on a simple and effective design, it is able to obtain low detection levels due to the low noise of the detection circuit. A circuit based on a lock‐in amplifier was designed on printed circuit boards to read out the signal. The property of the detection cell was studied by applying excitation signals of different frequencies and different amplitudes. It was found that the best detection limit could be achieved with a frequency of 50 kHz and amplitude of 20 V. The performance of the detector was demonstrated by successfully separating and detecting several inorganic ions and also a mixture of heavy metal ions. An average detection limit of 0.4 μM was obtained for inorganic cations. This value is significantly improved compared to similar microchip‐based detectors. The presented detector could be promising for mass production due to its properties, such as simple construction, high degree of integration, high performance and low cost.
Optimizing the extraction, separation and quantification of tricyclic antidepressant drugs in human plasma with CE‐ESI‐TOF‐MS using cationic‐coated capillaries
Authors: Elhamili Anisa , Samuelsson Jörgen , Bergquist Jonas , Wetterhall Magnus
Published: February 2011

In this study, the extraction and CE‐ESI‐TOF‐MS analysis of tricyclic antidepressant (TCA) drugs imipramine, desipramine, clomipramine and norclomipramine in human plasma has been optimized. The CE capillaries were modified with ω‐iodo‐alkyl ammonium salt (M7C4I coating) to reduce analyte adsorption to the silica wall. The use of a strong cation exchange (SCX) solid‐phase extraction (SPE) column specifically designed for the extraction of basic drug species from biofluids gave very clean extracts with high and reproducible recoveries. The extraction recoveries were ranging between 87 and 91% with % RSD values of 0.5–1.7% (n=3). The obtained strong cation exchange‐SPE extracts of the TCA in human plasma only contained the analytes of interest. The optimized CE separation conditions were obtained by adding ACN and acetic acid to the sample while using an aqueous BGE. The CE‐ESI‐TOF‐MS analysis was performed within 6 min for all TCA analytes under the optimized condition with peak efficiencies up to 1.4×105 plates/m and an average % RSD of the migration times of the analytes of 0.3% (n=5). The presented method can readily be used for the extraction and quantification of basic drug species in human biological fluids and in pharmaceutical formulations.
Predicting bioavailability of PAHs and PCBs with porewater concentrations measured by solid-phase microextraction fibers
Authors: Lu Xiaoxia , Skwarski Alison , Drake Brian , Reible Danny D
Published: February 2011

Bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) was measured in the deposit-feeding oligochaete Ilyodrilus templetoni exposed for 28 d to Anacostia River sediment (Washington, DC, USA) and to an initially uncontaminated sediment from Brown Lake (Vicksburg, MS, USA) sequentially diluted with 3 to 25% contaminated New Bedford Harbor sediment (New Bedford, MA, USA). The Anacostia River sediment studies represented exposure to a historically contaminated sediment with limited availability, whereas exposure to the other sediment included both the historically contaminated New Bedford Harbor sediment and fresh redistribution of contaminants into the Brown Lake sediments. Organism tissue concentrations did not correlate with bulk sediment concentrations in the Anacostia River sediment but did correlate with the sequentially diluted sediment. Porewater concentrations measured via disposable solid-phase microextraction fiber (SPME) with polydimethylsiloxane (PDMS), however, correlated well with organism uptake in all sediments. Bioaccumulation was predicted well by a linear relationship with the product of porewater concentration and compound octanol–water partition coefficient (Anacostia, slope = 1.08, r2 = 0.76; sequentially diluted sediments, slope = 1.24, r2 = 0.76). The data demonstrate that the octanol–water partition coefficient is a good indicator of the lipid–water partition coefficient and that porewater concentrations provide a more reliable indicator of bioaccumulation in the organism than sediment concentrations, even when the route of uptake is expected to be via sediment ingestion. Environ. Toxicol. Chem. 2011; 30:1109–1116. © 2011 SETAC
Panic or not in fire: Clarifying the misconception
Authors: Fahy Rita F. , Proulx Guylène , Aiman Lata
Published: February 2011

The word ‘panic’ is frequently used in media accounts and statements of survivors of emergency evacuations and fires, but what does it really mean, is it a phenomenon that actually occurs? This paper first examines the concept from the view of the general public, particularly the media. Definitions of panic behaviour related to emergency response are summarized and evidence of behaviour from actual fire incidents are presented through interview data and case studies. Despite the data demonstrating that panic is a very rare occurrence in fires, the idea of panic and the term continue to be used by the public as well as fire experts. It is therefore necessary to demystify the misconception that panic is an essential element of a fire and identify any scientific justification for continuing to use this concept. Copyright © 2011 John Wiley & Sons, Ltd.