bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthetic Uses of Ammonia in Transition‐Metal Catalysis
Authors: Kim Jinho , Kim Hyun Jin , Chang Sukbok
Published: April 2013

Ammonia (NH3) is a cheap, abundant, and readily available nitrogen source, being one of the chemicals produced in the greatest quantities. Whereas ammonia is utilized mainly as a feedstock for the production of fertilizers, it is also employed in industry as a component of various nitrogen‐containing compounds. In metal catalysis, in contrast, ammonia has been used only with limited success, due to several difficulties such as generation of stable Lewis acid‐base adducts, facile ligand exchange for ammonia in active metal complexes, a propensity towards undesired second transformations of initially formed species, and the requirement for special equipment to run the reactions. Despite these obstacles, the direct use of ammonia in catalysis has continuously attracted great interest, leading recently to significant progress. Whereas liquid or gaseous ammonia were most commonly employed in the past, under harsh conditions, notable catalytic reactions using easy‐to‐handle ammonium salts under milder and more convenient conditions have now been developed. In this review we briefly describe the most recent examples of transition‐metal‐catalyzed reactions using ammonia or ammonium salts.
Capillary electrophoresis with capacitively coupled contactless conductivity detection applied to the quantitation and to the determination of physical–chemical properties of peroxycarboxylates in aqueous medium
Authors: Vidal Denis T. R. , do Lago Claudimir L.
Published: April 2013

CE with C4D (CE‐C4D) was successfully applied to the investigation of performate, peracetate, and perpropionate in aqueous medium. Ionic mobilities, diffusion coefficients, and hydrodynamic radii were obtained for the first time for these species. CE‐C4D was also used to estimate the pKa values of the peroxycarboxylic acids. Because the peroxycarboxylates (POCs) undergoes hydrolysis while migrating, a simple calibration curve cannot be used for quantitation. Thus, an indirect calibration approach was used. The new method was used to monitor the formation of peroxycarboxylic acids from hydrogen peroxide and the carboxylic acid as well as to the quantitation of peracetic acid in a commercial sample. The CE‐C4D method compares favorably with the conventional titration method because of the possibility of speciation of the POC, the low sample consumption, and the low LOD (14, 8, and 24 μmol/L for performate, peracetate, and perpropionate, respectively). Although POCs are structural isomers of monoalkyl carbonates, they have greater hydrodynamic radii, which suggests that the positions of the oxygen atoms in the molecules have a direct impact in the charge density and consequently on the hydration atmosphere.
Capillary electrophoresis as a production tool for asymmetric microhybrids
Authors: Fattah Zahra , Garrigue Patrick , Goudeau Bertrand , Lapeyre Véronique , Kuhn Alexander , Bouffier Laurent
Published: April 2013

The site selective electrodeposition of silver metal onto a conducting object such as carbon microtubes (CMTs) in an electrolytic solution could be achieved by means of bipolar electrochemistry. Two half reactions are simultaneously carried out at both extremities of the CMT, which act as a bipolar electrode. The thermodynamic threshold value of the process, which consists in metal electroreduction and concomitant water oxidation is directly related to the length of CMT. That is the reason why, when scaling down the methodology to microscale objects, electric fields in the range of tenths of kilovolts per meter are necessary. In that context, a CE apparatus provides a convenient experimental platform to achieve in a straightforward manner such experimental conditions. We exemplify this methodology with the efficient and quick electroreduction of Ag+ on CMTs from a low‐concentration aqueous electrolytic solution during the migration across a fused capillary. CE allows applying safely a large enough electric field (typically ∼30 kV/m) for the successful modification of 15 to 20 μm‐long substrates. The corresponding hybrid materials have been characterized by optical microscopy as well as SEM and energy‐dispersive X‐ray spectroscopy.
Influence of Ca and pH on the uptake and effects of Cd in Folsomia candida exposed to simplified soil solutions
Authors: Ardestani Masoud M. , Ortiz Maria Diez , van Gestel Cornelis A.M.
Published: April 2013

The present study sought to quantify the components of a biotic ligand model (BLM) for the effects of Cd on Folsomia candida (Collembola). Assuming that soil porewater is the main route of exposure and to exclude the effects of soil particles on metal availability, animals were exposed for 7 d to different Cd concentrations between 0.1 mM and 100 mM in simplified soil solutions at different Ca concentrations (0.2 mM, 0.8 mM, 3.2 mM, and 12.8 mM) or at different pH (5.0, 6.0, and 7.0). Higher Ca concentrations decreased the toxicity of Cd (adult survival) in test solutions, whereas toxicity was slightly lower at pH 7 and 6 than at pH 5, suggesting a mitigating effect of Ca and to a lesser extent pH on Cd toxicity to F. candida. Internal Cd concentrations in the animals increased with increasing exposure level but were significantly reduced by increasing Ca concentrations and were not significantly affected by pH. By using Langmuir isotherms, binding constants for Cd, Ca, and protons and the fraction of binding sites occupied by Cd were calculated and used to predict effects of Cd on survival. Predicted toxicity showed a good agreement with measured responses when Ca and pH were used as separate factors or combined together. The present study shows indications of protective effects of Ca but less of protons on the toxicity and uptake of Cd in F. candida on exposure to simplified soil solutions, which can be described using the principles of a biotic ligand model. Environ Toxicol Chem 2013;32:1759–1767. © 2013 SETAC
Transmission and the Environment: Power to the People: Primer on NEPA and Transmission Lines
Authors: Orford Adam
Published: April 2013

Slowly but surely, the US economy is coming back to life.
Impact of atmospheric transport on the evolution of microphysical and optical properties of Saharan dust
Authors: Ryder C. L. , Highwood E. J. , Lai T. M. , Sodemann H. , Marsham J. H.
Published: April 2013

Saharan dust affects the climate by altering the radiation balance and by depositing minerals to the Atlantic Ocean. Both are dependent on particle size. We present aircraft measurements comprising 42 profiles of size distribution (0.1–300 µm), representing freshly uplifted dust, regional aged dust, and dust in the Saharan Air Layer (SAL) over the Canary Islands. The mean effective diameter of dust in SAL profiles is 4.5 µm smaller than that in freshly uplifted dust, while the vertical structure changes from a low shallow layer (0–1.5 km) to a well‐mixed deep Saharan dust layer (0–5 km). Size distributions show a loss of 60 to 90% of particles larger than 30 µm 12 h after uplift. The single scattering albedo (SSA) increases from 0.92 to 0.94 to 0.95 between fresh, aged, and SAL profiles: this is enough to alter heating rates by 26%. Some fresh dust close to the surface shows SSA as low as 0.85.
Montserrat geothermal system: A 3D conceptual model
Authors: Ryan G. A. , Peacock J. R. , Shalev E. , Rugis J.
Published: April 2013

We constructed a three‐dimensional conceptual model of a geothermal system on the Caribbean island of Montserrat. The model was generated using magnetotelluric resistivity data, earthquake hypocenter data, and a three‐dimensional P wave velocity model, all plotted using a shared geographical reference. The results of the study suggest a high‐temperature fracture‐controlled geothermal system at the intersection of two faults in the SW of the island. We also present a “prospectivity index” map that represents a proxy of the spatial variation in harvestable heat flux at 1500 m depth. The index is the product of relative permeability around modeled faults and a proxy for the subsurface temperature calculated using P wave velocity anomalies.
Effect of mine dewatering on the peatlands of the James Bay Lowland: the role of marine sediments on mitigating peatland drainage
Authors: Whittington Peter , Price Jonathan S.
Published: April 2013

The wetlands of the James Bay Lowland comprise one of largest wetland complexes in the world, in part due to the properties (thickness and hydraulic conductivity) of the marine sediment (MS) that underlay them. Dewatering of an open‐pit diamond mine is depressurizing the surrounding Silurian bedrock below the MS. Prior to mining, it was assumed that these MS would largely isolate the overlying peatlands from the depressurized regional bedrock aquifer. To assess this isolation, we instrumented a 1.5 km long transect of wells and piezometers located within the zone of the mine's influence that crossed a sequence of bogs, fens, and bedrock outcrops (bioherms). Results were differentiated between those areas with no MS (near bioherms) and those underlain by MS (non‐bioherm) along the transect. Between 2007 and 2010 at near‐bioherm and non‐bioherm locations, average peat water tables declined 71 and 31 cm, and hydraulic head declined 66 and 32 cm, in bioherm and non‐bioherm locations, respectively. Gradients varied from near zero (−0.001) at the start of dewatering to −0.03 (after 5 years) in non‐bioherm areas and from −0.20 to −0.45 in near‐bioherm areas. These gradients corresponded to fluxes (groundwater recharge) of approximately −0.26 mm/day and −2.1 mm/day, in non‐ and near‐bioherm areas, respectively. Specific discharge (recharge) determined using the known mine dewatering rate and drawdown cone heads and areas corresponded well with measured recharge determined in the non‐bioherm transect locations. A simple rearrangement of Darcy's Law used to calculate the specific discharge highlighted how the ratio of hydraulic conductivity to the thickness of the MS can be used to assess vulnerable areas. Therefore, given the increasing development in Ontario's Far North, considerable attention must be given to both the thickness and hydraulic conductivity of MS. Copyright © 2013 John Wiley & Sons, Ltd.
MODELLING LARGE OPEN ECONOMIES WITH INTERNATIONAL LINKAGES: THE USA AND EURO AREA
Authors: Dungey Mardi , Osborn Denise R.
Published: April 2013

Empirical modelling of the linkages between the euro area and the USA requires an open economy framework. The methodology proposed in this paper achieves identification of a structural vector error correction model by supplementing restrictions from economic theory with assumptions for the direction of causality in cross‐country contemporaneous relationships. Our baseline model assumes contemporaneous causality runs from the USA to the euro area for both output and inflation, with monetary policy domestically focused. The role of the USA as leading the euro area business cycle is reinforced by our results, but strong bidirectional cross‐country interactions are uncovered for inflation and interest rates. Copyright © 2013 John Wiley & Sons, Ltd.
Development of an integrated optical analyzer for characterization of growth dynamics of bacterial colonies
Authors: Kim Huisung , Bai Nan , Bhunia Arun K. , King Galen B. , Hirleman E. Daniel , Bae Euiwon
Published: April 2013

In order to understand the biophysics behind collective behavior of a bacterial colony, a confocal displacement meter was used to measure the profiles of the bacterial colonies, together with a custom built optical density circuits. The system delivered essential information related to the quantitative growth dynamics (height, diameter, aspect ratio, optical density) of the bacterial colony. For example, the aspect ratio of S. aureus was approximately two times higher than that of E. coli O157 : H7, while the OD of S. aureus was approximately 1/3 higher than that of E. coli O157 : H7. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Facile synthesis, characterization, and antimicrobial activity of cellulose–chitosan–hydroxyapatite composite material: A potential material for bone tissue engineering
Authors: Mututuvari Tamutsiwa M. , Harkins April L. , Tran Chieu D.
Published: April 2013

Hydroxyapatite (HAp) is often used as a bone‐implant material because it is biocompatible and osteoconductive. However, HAp possesses poor rheological properties and it is inactive against disease‐causing microbes. To improve these properties, we developed a green method to synthesize multifunctional composites containing: (1) cellulose (CEL) to impart mechanical strength; (2) chitosan (CS) to induce antibacterial activity thereby maintaining a microbe‐free wound site; and (3) HAp. In this method, CS and CEL were co‐dissolved in an ionic liquid (IL) and then regenerated from water. HAp was subsequently formed in situ by alternately soaking [CEL+CS] composites in aqueous solutions of CaCl2 and Na2HPO4. At least 88% of IL used was recovered for reuse by distilling the aqueous washings of [CEL+CS]. The composites were characterized using FTIR, XRD, and SEM. These composites retained the desirable properties of their constituents. For example, the tensile strength of the composites was enhanced 1.9 times by increasing CEL loading from 20% to 80%. Incorporating CS in the composites resulted in composites which inhibited the growth of both Gram positive (MRSA, S. aureus and VRE) and Gram negative (E. coli and P. aeruginosa) bacteria. These findings highlight the potential use of [CEL+CS+HAp] composites as scaffolds in bone tissue engineering. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 3266–3277, 2013.
The G60S connexin 43 mutation activates the osteoblast lineage and results in a resorption-stimulating bone matrix and abrogation of old-age–related bone loss
Authors: Zappitelli Tanya , Chen Frieda , Moreno Luisa , Zirngibl Ralph A , Grynpas Marc , Henderson Janet E , Aubin Jane E
Published: April 2013

We previously isolated a low bone mass mouse, Gja1Jrt/ + , with a mutation in the gap junction protein, alpha 1 gene (Gja1), encoding for a dominant negative G60S Connexin 43 (Cx43) mutant protein. Similar to other Cx43 mutant mouse models described, including a global Cx43 deletion, four skeletal cell conditional-deletion mutants, and a Cx43 missense mutant (G138R/ +), a reduction in Cx43 gap junction formation and/or function resulted in mice with early onset osteopenia. In contrast to other Cx43 mutants, however, we found that Gja1Jrt/+ mice have both higher bone marrow stromal osteoprogenitor numbers and increased appendicular skeleton osteoblast activity, leading to cell autonomous upregulation of both matrix bone sialoprotein (BSP) and membrane-bound receptor activator of nuclear factor-κB ligand (mbRANKL). In younger Gja1Jrt/+ mice, these contributed to increased osteoclast number and activity resulting in early onset osteopenia. In older animals, however, this effect was abrogated by increased osteoprotegerin (OPG) levels and serum alkaline phosphatase (ALP) so that differences in mutant and wild-type (WT) bone parameters and mechanical properties lessened or disappeared with age. Our study is the first to describe a Cx43 mutation in which osteopenia is caused by increased rather than decreased osteoblast function and where activation of osteoclasts occurs not only through increased mbRANKL but an increase in a matrix protein that affects bone resorption, which together abrogate age-related bone loss in older animals. © 2013 American Society for Bone and Mineral Research.
The Dynamics of Supernumerary Tooth Development Are Differentially Regulated by Sprouty Genes
Authors: LAGRONOVA‐CHURAVA SVATAVA , SPOUTIL FRANTISEK , VOJTECHOVA SIMONA , LESOT HERVE , PETERKA MIROSLAV , KLEIN OPHIR D. , PETERKOVA RENATA
Published: April 2013

In mice, a toothless diastema separates the single incisor from the three molars in each dental quadrant. In the prospective diastema of the embryo, small rudimentary buds are found that are presumed to be rudiments of suppressed teeth. A supernumerary tooth occurs in the diastema of adult mice carrying mutations in either Spry2 or Spry4. In the case of Spry2 mutants, the origin of the supernumerary tooth involves the revitalization of a rudimentary tooth bud (called R2), whereas its origin in the Spry4 mutants is not known. In addition to R2, another rudimentary primordium (called MS) arises more anteriorly in the prospective diastema. We investigated the participation of both rudiments (MS and R2) in supernumerary tooth development in Spry2 and Spry4 mutants by comparing morphogenesis, proliferation, apoptosis, size and Shh expression in the dental epithelium of MS and R2 rudiments. Increased proliferation and decreased apoptosis were found in MS and R2 at embryonic day (ED) 12.5 and 13.5 in Spry2−/− embryos. Apoptosis was also decreased in both rudiments in Spry4−/− embryos, but the proliferation was lower (similar to WT mice), and supernumerary tooth development was accelerated, exhibiting a cap stage by ED13.5. Compared to Spry2−/− mice, a high number of Spry4−/− supernumerary tooth primordia degenerated after ED13.5, resulting in a low percentage of supernumerary teeth in adults. We propose that Sprouty genes were implicated during evolution in reduction of the cheek teeth in Muridae, and their deletion can reveal ancestral stages of murine dental evolution. J. Exp. Zool. (Mol. Dev. Evol.) 320B:307–320, 2013. © 2013 Wiley Periodicals, Inc.
Regional and local increases in storm intensity in the San Francisco Bay Area, USA, between 1890 and 2010
Authors: Russo Tess A. , Fisher Andrew T. , Winslow Dustin M.
Published: April 2013

Studies of extreme precipitation have documented changes at the continental scale during the twentieth century, but few studies have quantified changes at small to regional spatial scales during the same time. We analyze historic data from over 600 precipitation stations in the San Francisco Bay Area (SFBA), California, to assess whether there have been statistically significant changes in extreme precipitation between 1890 and 2010. An annual exceedance probability analysis of extreme precipitation events in the SFBA, coupled with a Markov chain Monte Carlo algorithm, reveals an increase in the occurrence of large events. The depth‐duration‐frequency characteristics of maximum annual precipitation events having durations of 1 h to 60 days indicate on average an increase in storm intensity in the last 120 years, with the intensity of the largest (least frequent) events increasing the most. Mean annual precipitation (MAP) also increased during the study period, but the relative increase in extreme event intensity exceeds that of MAP, indicating that a greater fraction of precipitation fell during large events. Analysis of data from subareas within the SFBA region indicates considerable heterogeneity in the observed nonstationarity; for example, the 5 day, 25 year event exceedance depth changed by +26%, +16%, and −1% in San Francisco, Santa Rosa, and San Jose, respectively. These results emphasize the importance of analyzing local data for accurate risk assessment, emergency planning, resource management, and climate model calibration.
Exploration of fluoroquinolone resistance in Streptococcus pyogenes: comparative structure analysis of wild‐type and mutant DNA gyrase
Authors: Shafreen Raja Mohmed Beema , Selvaraj Chandrabose , Singh Sanjeev Kumar , Pandian Shunmugiah Karutha
Published: April 2013

Quinolone resistance‐determining region is known to be the druggability site of the target protein that undergoes frequent mutation and thus renders quinolone resistance. In the present study, ligands were tested for their inhibitory activity against DNA gyrase of Streptococcus pyogenes involved in DNA replication. In silico mutational analysis on modelled gyrase A revealed that GLU85 had the most possible interactions with all the ligands used for the study. The amino acid residue GLU85 had also been predicted with an essential role of maintaining the three‐dimensional structure of the protein. When introduced with a mutation (GLU 85 LYS) on this particular residue, it had readily denatured the whole α‐helix (from 80 to 90 amino acids). This was confirmed through the molecular dynamics simulation and revealed that this single mutation can cause many functional and structural changes. Furthermore, LYS85 mutation has altered the original secondary structure of the protein, which in turn led to the steric hindrance during the ligand–receptor interaction. The results based on the G‐score revealed that ligands have reduced interaction with the mutant protein. The semisynthetic fluoroquinolone 6d, which is an exception, forms a strong interaction with the mutant protein and was experimentally verified using the antimicrobial test. Hence, the present study unravels the fact that mutation at the drug binding site is the major cause for different level of resistance by the S. pyogenes when exposed against the varying concentrations of the fluoroquinolones. Furthermore, a comparative assessment of quinolone derivative with the older generation fluoroquinolones will be of great impact for S. pyogenes–related infections. Copyright © 2013 John Wiley & Sons, Ltd.
Multiparametric MRI of prostate cancer: An update on state‐of‐the‐art techniques and their performance in detecting and localizing prostate cancer
Authors: Hegde John V. , Mulkern Robert V. , Panych Lawrence P. , Fennessy Fiona M. , Fedorov Andriy , Maier Stephan E. , Tempany Clare M.C.
Published: April 2013

Magnetic resonance (MR) examinations of men with prostate cancer are most commonly performed for detecting, characterizing, and staging the extent of disease to best determine diagnostic or treatment strategies, which range from biopsy guidance to active surveillance to radical prostatectomy. Given both the exam's importance to individual treatment plans and the time constraints present for its operation at most institutions, it is essential to perform the study effectively and efficiently. This article reviews the most commonly employed modern techniques for prostate cancer MR examinations, exploring the relevant signal characteristics from the different methods discussed and relating them to intrinsic prostate tissue properties. Also, a review of recent articles using these methods to enhance clinical interpretation and assess clinical performance is provided. J. Magn. Reson. Imaging 2013;37:1035–1054. © 2013 Wiley Periodicals, Inc.
In vivo validation of 4D flow MRI for assessing the hemodynamics of portal hypertension
Authors: Roldán‐Alzate Alejandro , Frydrychowicz Alex , Niespodzany Eric , Landgraf Ben R. , Johnson Kevin M. , Wieben Oliver , Reeder Scott B.
Published: April 2013

Purpose:

To implement and validate in vivo radial 4D flow MRI for quantification of blood flow in the hepatic arterial, portal venous, and splanchnic vasculature of healthy volunteers and patients with portal hypertension.

Materials and Methods:

Seventeen patients with portal hypertension and seven subjects with no liver disease were included in this Health Insurance Portability and Accountability Act (HIPAA)‐compliant and Institutional Review Board (IRB)‐approved study. Exams were conducted at 3T using a 32‐channel body coil with large volumetric coverage and 1.4 mm isotropic true spatial resolution. Using postprocessing software, cut‐planes orthogonal to vessels were used to quantify flow (L/min) in the hepatic and splanchnic vasculature.

Results:

Flow quantification was successful in all cases. Portal vein and supraceliac aorta flow demonstrated high variability among patients. Measurements were validated indirectly using internal consistency at three different locations within the portal vein (error = 4.2 ± 3.9%) and conservation of mass at the portal confluence (error = 5.9 ± 2.5%) and portal bifurcation (error = 5.8 ± 3.1%).

Conclusion:

This work demonstrates the feasibility of radial 4D flow MRI to quantify flow in the hepatic and splanchnic vasculature. Flow results agreed well with data reported in the literature, and conservation of mass provided indirect validation of flow quantification. Flow in patients with portal hypertensions demonstrated high variability, with patterns and magnitude consistent with the hyperdynamic state that commonly occurs in portal hypertension. J. Magn. Reson. Imaging 2013. © 2012 Wiley Periodicals, Inc.
Near Misses in High–Risk Occupations
Authors: Yorio Patrick L. , Wachter Jan K.
Published: April 2013

In this study, the authors hypothesize that safety‐specific job engagement is important to prevent occupational near misses in high‐risk occupations. The authors also hypothesize that safety program–focused justice perceptions and the absence of job distractions provide the workplace conditions necessary to support this engagement. Further, safety‐specific job engagement mediates the prediction of occupational near misses by justice perceptions and job distractions. Results of a survey administered to 2,488 full‐time employees working in the manufacturing, nuclear research and production, and mining industries provide support for the hypothesized relationships among the individual constructs and partial support for the mediation hypothesis. Through structural equation modeling, the authors found that safety‐specific job engagement mediated the relationship between safety program–focused justice perceptions and near misses. Another finding was that the relationship among job distractions, safety‐specific job engagement, and near misses is more complex, and a clear understanding of their relationship is subject to future investigation.
Exploring the Role of Valence and Regulation Type on the Emotional Antecedents of Burnout
Authors: Packell Kathryn , Narayan Anupama
Published: April 2013

We examined the predictive relationships between distinct types of emotional regulation and psychological burnout in a sample of 85 practicing nurse professionals. Hierarchical regression analyses were used to predict emotional exhaustion, cynicism, and reduced professional efficacy from the genuine expression, faking, and suppression of discrete positive and negative emotions. The genuine expression of negative emotions predicted emotional exhaustion, and the genuine expression of positive emotions predicted cynicism and reduced professional efficacy. Results highlight the value of distinguishing among emotional valences and regulation types when examining the emotional antecedents of worker stress.
Application of the precolumn back‐flush technology in pesticide residue analysis: A practical view
Authors: Hildmann Fanny , Kempe Günther , Speer Karl
Published: April 2013

Precolumn back‐flushing is a matrix minimization technique in GC in which the carrier gas flow of the precolumn is reversed after the transfer of the highest boiling analyte to the analytical column. Practical details concerning this technology have rarely been published although it is widely used. This paper now focuses on the practical implementation of precolumn back‐flushing for pesticide residue analysis of complex food matrices. Fitting the analytical column into the precolumn was found to be essential for comparable analyte responses with and without back‐flushing. The effectiveness of the reverse column flow technique is mainly affected by the transfer time after which back‐flushing starts. The transfer time was found to depend on which kind of injected matrix is used and the state of the precolumn. For the regular adaptation of the transfer time in routine analysis, a simple test was introduced in which 13‐C‐labeled deltamethrin and indeno[1,2,3‐c,d]pyrene were added to the prepared extract. Chromatograms, LOQ and RSD of up to 99 pesticides in citrus oil and liver extracts proved a clearer identification and enhanced quantification using precolumn back‐flushing compared to measurements without this technology. Furthermore, reduced system maintenance could be achieved through back‐flushing.
Children with a history of prematurity presenting with snoring and sleep‐disordered breathing
Authors: Manuel Anura , Witmans Manisha , El‐Hakim Hamdy
Published: April 2013

Objectives/Hypothesis

To report on the prevalence of premature (PM) birth in a consecutive series of children treated for snoring and sleep‐disordered breathing (S/SDB), the parameters specific to their management and variables predictive of disease severity.

Study Design

A retrospective study was undertaken at a tertiary pediatric hospital.

Methods

Children with history of PM and presenting with S/SDB were identified from a prospectively kept surgical database. We set out to determine the prevalence of PM among the patients presenting with S/SDB who required airway evaluations and surgery. Pulse oximetry is overnight recordable oxygen saturation and heart rate tracing that provides information about hypoxemia during sleep. This was performed on all children preoperatively. The pulse oximetry findings were used to plan for perioperative monitoring and care. A multivariable analysis was used to identify factors predictive of abnormal pulse oximetry studies. We evaluated the associated diagnoses, surgical procedures required, and response to treatment in these selected children.

Results

Fifty‐seven out of 1,038 patients were PM (33 males; mean age, 62.09±34.91 months; range, 4–190 months). The mean gestational age was 30.3±4.0 weeks. The prevalence rate of PM among patients treated surgically for SDB is 5.5% (95% CI 5.2–5.8) at our center. Comorbid pulmonary and gastrointestinal disorders were encountered on 23 (40%) and 17 (29.8%) occasions, respectively, and were the most commonly encountered comorbid diagnostic categories. Large airway abnormalities were encountered in 11 (19.3%) children, and the most common were subglottic stenosis (four) and laryngeal paralysis (four). Comorbid respiratory disease was negatively predictive of abnormal pulse oximetry (coefficient −0.35, P<.05). Postoperative respiratory outcomes correlated with abnormal pulse oximetry (coefficient 0.3; P<.05).

Conclusions

Our findings suggest children with PM presenting to pediatric otolaryngology require a comprehensive evaluation for S/SDB. A significant proportion of children with S/SDB and a history of PM frequently had pulmonary and gastrointestinal comorbidities in our cohort. One‐half required admission postoperatively, and these were predictable based on preoperative pulse oximetry. Respiratory comorbidity was negatively predictive of severity of SDB. Inversely, children with untreated pulmonary comorbidities are more likely to have postoperative complications.

Level of Evidence

2b. Laryngoscope, 123:2030–2034, 2013
Bandgap and Molecular‐Energy‐Level Control of Conjugated‐Polymer Photovoltaic Materials Based on 6,12‐Dihydro‐diindeno[1,2‐b;10,20‐e]pyrazine
Authors: Shen Ping , Liu Xinping , Tang Peng , Zhao Bin , Wang Ling , Weng Chao , Cao Jing , Wu Yongxiang , Chen Ya , Tan Songting
Published: April 2013

Six conjugated polymers based on the indenopyrazine (IPY) unit are designed and synthesized by copolymerization with different electron‐deficient and electron‐rich building blocks. All of the polymers show good solubility, excellent film‐forming ability, and low‐lying highest occupied molecular orbit (HOMO) energy levels. The effects of the different copolymerized units on the optical, electrochemical, and photovoltaic properties are investigated. Results indicate that their bandgaps and molecular energy levels are readily tuned by copolymerizing with electron‐deficient and electron‐rich units. Polymer solar‐cell devices are fabricated utilizing the polymers as electron donors and [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) as an electron acceptor. The best power conversion efficiency of the cell based on PIPY‐DTBTA, one of the IPY‐ based polymers, reaches 0.77%, with a relatively high Voc up to 0.78 V.

magnified image
Fast magnetization transfer and apparent T1 imaging using a short saturation pulse with and without inversion preparation
Authors: Kim Tae , Shin Wanyong , Kim Seong‐Gi
Published: April 2013

Purpose

Measurements of magnetization transfer (MT) metrics, such as the steady‐state (SS) MT ratio and apparent longitudinal relaxation rate require multiple MT irradiation durations and a long experimental time. To overcome these problems, we propose a novel method using a short MT off‐resonance pulse with and without on‐resonance inversion preparation pulse.

Theory and Methods

Computer simulations were performed to examine the accuracy of the proposed method and to find the optimal off‐resonance irradiation pulse duration (Tirad) and power level (ω1). Our approach, with echo planar imaging data acquisition, was applied to animals at 9.4 T and humans at 3 T with ω1/2π = 100 Hz and 177 Hz, respectively. Steady‐state MT ratio and relaxation rate were obtained from a pair of MT images at a Tirad, with and without inversion.

Results

For Tirad ≥ 0.4 s, steady‐state MT ratio, and relaxation rate measured at any single Tirad agreed well with those of the conventional fitting method that uses multiple Tirad. Our simulation indicates that a higher ω1 can use a shorter Tirad.

Conclusion

Steady‐state MT ratio and relaxation rate can be determined from MT data with only one, short Tirad by incorporation of an inversion prepulse. This MT imaging approach is simple, fast, and easily implementable. Magn Reson Med 71:1264–1271, 2014. © 2013 Wiley Periodicals, Inc.
Psychological distress in African American grandmothers raising grandchildren: The contribution of child behavior problems, physical health, and family resources
Authors: Kelley Susan J. , Whitley Deborah M. , Campos Peter E.
Published: April 2013

Diminished psychological health has been identified among caregiving grandmothers. The intent of this investigation was to examine psychological distress levels, as well as their predictors, in a sample of 480 caregiving African American grandmothers, mean age 56 years. Almost 40% (39.8%) of participants had clinically elevated psychological distress scores. Results of hierarchical multiple regression indicated that internalizing and externalizing child behavior problems, poor grandmother physical health, younger age of grandmother, and lack of family resources predicted 31% of the variance in psychological distress. Results provide direction for nursing interventions aimed at enhancing the psychological well‐being of caregiving grandmothers. © 2013 Wiley Periodicals, Inc. Res Nurs Health 36: 373–385, 2013
Testing the efficacy of culturally adapted coping skills training for Chinese American immigrants with type 2 diabetes using community‐based participatory research
Authors: Chesla Catherine A. , Chun Kevin M. , Kwan Christine M.L. , Mullan Joseph T. , Kwong Yulanda , Hsu Lydia , Huang Peggy , Strycker Lisa A. , Shum Tina , To Diana , Kao Rudy , Waters Catherine M.
Published: April 2013

Chinese Americans demonstrate greater prevalence of diabetes than non‐Hispanic whites and find standard diabetes care disregards their cultural health beliefs. Academic researchers and Chinatown agencies collaborated to culturally adapt and test an efficacious cognitive‐behavioral intervention using community‐based participatory research. Using a delayed‐treatment repeated‐measures design, 145 adult Chinese immigrants with Type 2 diabetes completed treatment. Immediate benefits of treatment were evident in the improvement (p < .05) in diabetes self‐efficacy, diabetes knowledge, bicultural efficacy, family emotional and instrumental support, diabetes quality of life, and diabetes distress. Prolonged benefits were evident in all changed variables 2 months post‐intervention. The CBPR approach enabled the development of a culturally acceptable, efficacious behavioral intervention, and provides a model for working with communities that demonstrate health disparities. © 2013 Wiley Periodicals, Inc. Res Nurs Health 36: 359–372, 2013
Elaboration of cellulose acetate nanobiocomposites using acidified gelatin‐montmorillonite as nanofiller: Morphology, properties, and biodegradation studies
Authors: Ferfera‐Harrar Hafida , Dairi Nassima
Published: April 2013

Nanobiocomposites were successfully prepared from cellulose acetate (CA) and a novel organoclay based on montmorillonite and acidified gelatin as bio‐modifier (AGe‐MMT), at room temperature via solvent casting process. The formation of AGe‐MMT was confirmed by Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), differential Scanning Calorimetry (DSC), and thermogravimetric analysis (TGA). From both XRD and transmission electron microscopy (TEM) analyses of these nanohybrids, it was suggested a partially exfoliated/intercalated structures, with small clay tactoïds remaining. Glass transition (Tg) and melting (Tm) temperatures of the nanobiocomposites, evaluated by DSC analysis, were slightly affected by clay loading compared to neat CA. Significant improvement in their thermal stabilities was observed from TGA, as evidenced by the shift of their Tdonset toward higher values. Otherwise, the optical clarity of these nanohybrids films, measured by UV–vis spectroscopy, has showed a decline in the transmittance in the visible region with the increase of clay content, indicating that clay platelets are not fully exfoliated. The impact of AGe‐MMT on biodegradability of CA under compost was also studied by gravimetric and Scanning Electron Microscopy (SEM). The CA matrix biodegradability was retarded by both MMT and bio‐modifier, except for 5 wt% AGe‐MMT loading. POLYM. COMPOS., 34:1515–1524, 2013. © 2013 Society of Plastics Engineers
Advanced composites for hard‐tissue engineering based on PCL/organic–inorganic hybrid fillers: From the design of 2D substrates to 3D rapid prototyped scaffolds
Authors: De Santis R. , Gloria A. , Russo T. , D'Amora U. , D'Antò V. , Bollino F. , Catauro M. , Mollica F. , Rengo S. , Ambrosio L.
Published: April 2013

The bioactivity of sol–gel synthesized poly(ε‐caprolactone) (PCL)/TiO2 or poly(ε‐caprolactone)/ZrO2 particles was already known. In designing innovative 2D composite substrates for hard‐tissue engineering, the possibility to embed PCL/TiO2 or PCL/ZrO2 hybrid fillers into a PCL matrix was previously proposed. In the present study, the potential of 3D fiber‐deposition technique to design morphologically controlled scaffolds consisting of PCL reinforced with PCL/TiO2 or PCL/ZrO2 hybrid fillers was demonstrated. Finite element analysis was initially carried out on 2D substrates to find a correlation between the previously obtained results from the small punch test and the Young's modulus of the materials, whilst mechanical and biological tests were suitably performed on rapid prototyped scaffolds to assess the effects of the inclusion of the hybrid fillers on the performances of the 3D porous structures. The role of the inclusion of the hybrid fillers in improving the compressive modulus (about 90 MPa) and the cell viability/proliferation was demonstrated. POLYM. COMPOS., 34:1413–1417, 2013. © 2013 Society of Plastics Engineers
Reversal of Oral Anticoagulation
Authors: Thigpen Jonathan L. , Limdi Nita A.
Published: April 2013

Although the use of dabigatran and rivaroxaban are increasing, data on the reversal of their effects are limited. The lack of reliable monitoring methods and specific reversal agents renders treatment strategies empirical, and as a result, treatment consists mainly of supportive measures. Therefore, we performed a systematic search of the PubMed database to find studies and reviews pertaining to oral anticoagulation reversal strategies. This review discusses current anticoagulation reversal recommendations for the oral anticoagulants warfarin, dabigatran, and rivaroxaban for patients at a heightened risk of bleeding, actively bleeding, or those in need of preprocedural anticoagulation reversal. We highlight the literature that shaped these recommendations and provide directions for future research to address knowledge gaps. Although reliable recommendations are available for anticoagulation reversal in patients treated with warfarin, guidance on the reversal of dabigatran and rivaroxaban is varied and equivocal. Given the increasing use of the newer agents, focused research is needed to identify effective reversal strategies and develop and implement an accurate method (assay) to guide reversal of the newer agents. Determining patient‐specific factors that influence the effectiveness of reversal treatments and comparing the effectiveness of various treatment strategies are pertinent areas for future anticoagulation reversal research.
Microgel particles: The structure‐property relationships and their biomedical applications
Authors: Dai Zhuojun , Ngai To
Published: April 2013

Microgels are crosslinked soft particles with a three‐dimensional network structure that are swollen in a good solvent. They have frequently been termed “smart materials” since the size, softness, and interaction forces between particles are tunable by external stimuli such as temperature, pH, or magnetic and electric fields. It is this unique feature that has captured the interest of many scientists across a wide range of disciplines. This brief review covers the basic aspects of the relationships between the network structure and gel properties of the thermally sensitive poly(N‐isopropylacrylamide) (pNIPAM) microgels including the phase transition process, the internal structure of microgels, and the phase behavior. Additionally, we highlight the impacts of microgels on the biomedical applications, especially in the gene delivery, cell matrix and differentiation of stem cells. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2995–3003
The benefits of being self‐determined in promoting physical activity and affective well‐being among women recently treated for breast cancer
Authors: Brunet Jennifer , Burke Shaunna M. , Sabiston Catherine M.
Published: April 2013

Purpose

In this study, changes in motivational regulations in women following treatment for breast cancer were described. Changes in motivational regulations as predictors of subsequent change in light and moderate‐to‐vigorous physical activity (PA) and affect were also examined.

Methods

Women [n = 150; Mage = 54.41 (SD = 10.87) years] completed self‐report questionnaires and wore an accelerometer for 7 days at Time 1 [M = 3.94 (SD = 3.08) months following primary treatment], as well as 3 (Time 2) and 6 (Time 3) months later. Data were analyzed using repeated‐measures analysis of variance and path analysis using residual change scores.

Results

Identified regulation and self‐determined motivation (i.e., combined intrinsic motivation and identified regulation) scores decreased over time (p < 0.05). In the path model [χ2(4) = 5.66, p = 0.22, root mean square error of approximation = 0.05 (90% CI: 0.0; 0.15), comparative fit index = 0.99, standardized root mean square of the residuals = 0.03], ΔTime1–2 in external regulation was associated with ΔTime2–3 in positive affect (β = −0.16), ΔTime1–2 in introjected (β = 0.25) and amotivation (β = 0.19) were related to ΔTime2–3 in negative affect, and ΔTime1–2 in self‐determined motivation was related to ΔTime2–3 in positive affect (β = 0.40) and moderate‐to‐vigorous PA (β = 0.21).

Conclusions

Changes in motivational regulations were related to changes in PA and affect in the aftermath of breast cancer. Given the benefits of self‐determined motivation, additional research is needed to develop and test interventions aimed at enhancing this type of motivation. Copyright © 2013 John Wiley & Sons, Ltd.
Statistical inference on censored data for targeted clinical trials under enrichment design
Authors: Chen Chen‐Fang , Lin Jr‐Rung , Liu Jen‐Pei
Published: April 2013

For the traditional clinical trials, inclusion and exclusion criteria are usually based on some clinical endpoints; the genetic or genomic variability of the trial participants are not totally utilized in the criteria. After completion of the human genome project, the disease targets at the molecular level can be identified and can be utilized for the treatment of diseases. However, the accuracy of diagnostic devices for identification of such molecular targets is usually not perfect. Some of the patients enrolled in targeted clinical trials with a positive result for the molecular target might not have the specific molecular targets. As a result, the treatment effect may be underestimated in the patient population truly with the molecular target. To resolve this issue, under the exponential distribution, we develop inferential procedures for the treatment effects of the targeted drug based on the censored endpoints in the patients truly with the molecular targets. Under an enrichment design, we propose using the expectation–maximization algorithm in conjunction with the bootstrap technique to incorporate the inaccuracy of the diagnostic device for detection of the molecular targets on the inference of the treatment effects. A simulation study was conducted to empirically investigate the performance of the proposed methods. Simulation results demonstrate that under the exponential distribution, the proposed estimator is nearly unbiased with adequate precision, and the confidence interval can provide adequate coverage probability. In addition, the proposed testing procedure can adequately control the size with sufficient power. On the other hand, when the proportional hazard assumption is violated, additional simulation studies show that the type I error rate is not controlled at the nominal level and is an increasing function of the positive predictive value. A numerical example illustrates the proposed procedures. Copyright © 2013 John Wiley & Sons, Ltd.
Protective Effects of HemoHIM on Immune and Hematopoietic Systems Against γ‐Irradiation
Authors: Park Hae‐Ran , Jo Sung‐Kee , Jung Uhee , Yee Sung‐Tae , Kim Sung‐Ho
Published: April 2013

We examined the effect of HemoHIM on the protective efficacy of hematopoietic stem cells and on the recovery of immune cells against sublethal doses of ionizing radiation. Two‐month‐old mice were exposed to γ‐rays at a dose of 8, 6.5, or 5 Gy for a30‐day survival study, endogenous spleen colony formation, or other experiments, respectively. HemoHIM was injected intraperitoneally before and after irradiation. Our results showed that HemoHIM significantly decreased the mortality of sublethally irradiated mice. The HemoHIM administration decreased the apoptosis of bone marrow cells in irradiated mice. On the other hand, HemoHIM increased the formation of endogenous spleen colony in irradiated mice. In irradiated mice, the recovery of total leukocytes in the peripheral blood and lymphocytes in the spleen were enhanced significantly by HemoHIM. Moreover, the function of B cells, T cells, and NK cells regenerated in irradiated mice were significantly improved by the administration of HemoHIM. HemoHIM showed an ideal radioprotector for protecting hematopoietic stem cells and for accelerating the recovery of immune cells. We propose HemoHIM as a beneficial supplement drug during radiotherapy to alleviate adverse radiation‐induced effects for cancer patients. Copyright © 2013 John Wiley & Sons, Ltd.