bluuebunny/crossref_metadata_2025 huggingface dataset:
Environmental sustainability and climate change mitigation—CCS technology, better having it than not having it at all!
Authors: Butt T.E. , Giddings R.D. , Jones K.G.
Published: February 2012

Climate change is happening and already manifested in a range of ways, including: global warming, rising sea levels, floods, heat‐waves, stronger and more frequent storms, and droughts. One of the major factors in climate change is anthropogenic fossil fuel combustion for energy generation and it is increasing throughout the world. Fossil fuel burning results in carbon emissions. On the basis of the most recent evidence, this article presents some new insights into the carbon dioxide capture and storage (CCS) technology, which can be an environmentally sustainable way to control carbon emissions. The article also focuses on various relevant facts and figures from the literature on CCS technology and explores various challenges that the technology may face in future. © 2012 American Institute of Chemical Engineers Environ Prog, 2012
Influence of electrode material and electrode distance on bioelectricity production from sago‐processing wastewater using microbial fuel cell
Authors: Sangeetha T. , Muthukumar M.
Published: February 2012

Microbial fuel cells (MFC) are hybrid bioelectrochemical devices, which generate electrical energy through the oxidation of organic matter catalyzed by bacteria. In this research, the influence of electrode distance and different electrode materials on power production and chemical oxygen demand (COD) removal using raw sago‐processing wastewater were studied. Effect of electrode distance on MFC performance was carried out by varying it as 10, 12 and 15 cm. This study revealed that electrode distance of 10 cm resulted in increased power production with a voltage of 900 mV (millivolts), current of 9.0 mA (milliamps) at 100 Ω and COD removal of 94% compared to electrode distance of 12 and 15 cm. Graphite electrodes were good in power production compared to aluminum, stainless steel, and iron electrodes. Biofilm examination on the anode showed the presence of gram‐negative rod (E. coli) bacteria which might have contributed for power production. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 390‐395, 2013
Identification of odour‐active compounds in dried and roasted nori (Porphyra yezoensis) using a simplified gas chromatography–SNIF technique
Authors: Shu Na , Shen Hong
Published: February 2012

Dried and roasted nori (Porphyra yezoensis) were extracted with dichloromethane, and the extracts were distilled under high vacuum using a solvent assisted flavour evaporation (SAFE) apparatus to remove the non‐volatiles. The SAFE distillates were fractionated by acid and base washes. The odour‐active compounds were determined using a simplified gas chromatography–SNIF method. From the detection frequencies and the intensities of the peaks, and based on mass spectral data, retention indices, olfactory character, and co‐injection of authentic standards, 14 chemicals were identified as the odour‐active compounds in both dried and roasted nori, 16 were identified in dried nori, and 34 were identified in roasted nori. The differences in the chemical components of dried and roasted nori were compared. Copyright © 2012 John Wiley & Sons, Ltd.
Characterization and biological activity of essential oils from fruits of Zanthoxylum xanthoxyloides Lam. and Z. leprieurii Guill. & Perr., two culinary plants from Cameroon
Authors: Fogang Hervet P.D. , Tapondjou Léon A. , Womeni Hilaire M. , Quassinti Luana , Bramucci Massimo , Vitali Luca A. , Petrelli Dezemona , Lupidi Giulio , Maggi Filippo , Papa Fabrizio , Vittori Sauro , Barboni Luciano
Published: February 2012

Essential oils obtained by hydrodistillation of dried fruits of Zanthoxylum xanthoxyloides and Z. leprieurii (Rutaceae), were analysed by gas chromagraphy–flame ionization detection and gas chromatography–mass spectrometry. In the former, the major volatiles resulted citronellol (29.9%) and geraniol (11.5%), followed by citronellyl acetate (5.5%), limonene (5.5%) and citronellal (4.6%), while in the latter the major compounds were (E)‐β‐ocimene (29.4%), myrcene (28.6%), limonene (13.6%) and α‐pinene (8.1%), respectively. The chemical composition supports the traditional use of these plants as spices in local food. The oils were also tested for antiproliferative, antimicrobial and antioxidant activities by MTT assay, agar disc diffusion method, and DPPH, ABTS and β‐carotene–linoleic acid assay, respectively. The noteworthy cytotoxic effects of Z. xanthoxyloides are probably related to the presence of geraniol and citronellol, which exhibited strong antiproliferative activity against all the tested human tumor cell lines, and support the local traditional use of this plant for the treatment of various cancers. Copyright © 2012 John Wiley & Sons, Ltd.
Global environmental regulation: Current status of carbon markets and carbon credits
Authors: Deatherage Scott D.
Published: February 2012

Climate change is at the heart of political and legislative debates, international treaty negotiations, religious discussion, and daily media stories. Climate‐change legislation did not pass in the US Congress, but the United States Environmental Protection Agency (EPA) has issued greenhouse gas (GHG) regulations under a 2007 US Supreme Court decision based on the Federal Clean Air Act. Thus, national GHG regulation is going forward in the United States, to the surprise of many who are not involved in environmental issues or regulated under the EPA program.
Specialist mental health consultation for depression in Australian aged care residents with dementia: a cluster randomized trial
Authors: McSweeney Kate , Jeffreys Aimee , Griffith Joanne , Plakiotis Chris , Kharsas Renee , O'Connor Daniel W.
Published: February 2012

Objective

This cluster randomized controlled trial sought to determine whether multidisciplinary specialist mental health consultation was more effective than care as usual in treating the depression of aged care residents with dementia.

Methods

Three hundred and eighty nine aged care residents were screened for dementia and major depression. Forty four were ultimately included in the intervention sample, selected from 20 aged care facilities located in Melbourne, Australia. Facilities were randomly allocated to an intervention condition involving the provision of multidisciplinary specialist consultation regarding the best‐practice management of depression in dementia, or to a care as usual condition. Consultations involved individually tailored medical and psychosocial recommendations provided to care staff and general practitioners. All residents participated in a comprehensive pre‐intervention diagnostic assessment, including the administration of the Cornell Scale for Depression in Dementia. This assessment was repeated approximately 15 weeks post‐intervention by a rater blind to study condition.

Results

Multidisciplinary specialist mental health consultation was significantly more effective than care as usual in treating the clinical depression of aged care residents with dementia (p < 0.05, partial η2 = 0.16). At follow‐up, the mean Cornell Scale for Depression in Dementia score for the intervention group was 9.47, compared with 14.23 for the control group. In addition, 77% of the intervention group no longer met criteria for major depression.

Conclusions

The results of this study suggest that the psychosocial and medical management of depressed aged care residents can be improved by increasing access to specialist mental health consultation. Copyright © 2012 John Wiley & Sons, Ltd.
Identifying fragments of natural speech from the listener's MEG signals
Authors: Koskinen Miika , Viinikanoja Jaakko , Kurimo Mikko , Klami Arto , Kaski Samuel , Hari Riitta
Published: February 2012

It is a challenge for current signal analysis approaches to identify the electrophysiological brain signatures of continuous natural speech that the subject is listening to. To relate magnetoencephalographic (MEG) brain responses to the physical properties of such speech stimuli, we applied canonical correlation analysis (CCA) and a Bayesian mixture of CCA analyzers to extract MEG features related to the speech envelope. Seven healthy adults listened to news for an hour while their brain signals were recorded with whole‐scalp MEG. We found shared signal time series (canonical variates) between the MEG signals and speech envelopes at 0.5–12 Hz. By splitting the test signals into equal‐length fragments from 2 to 65 s (corresponding to 703 down to 21 pieces per the total speech stimulus) we obtained better than chance‐level identification for speech fragments longer than 2–3 s, not used in the model training. The applied analysis approach thus allowed identification of segments of natural speech by means of partial reconstruction of the continuous speech envelope (i.e., the intensity variations of the speech sounds) from MEG responses, provided means to empirically assess the time scales obtainable in speech decoding with the canonical variates, and it demonstrated accurate identification of the heard speech fragments from the MEG data. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.
Differential functional response in the posteromedial cortices and hippocampus to stimulus repetition during successful memory encoding
Authors: Vannini Patrizia , Hedden Trey , Sullivan Caroline , Sperling Reisa A.
Published: February 2012

The reduction of neural activity in response to repeated stimuli, repetition suppression, is one of the most robust experience‐related cortical dynamics known to cognitive neuroscience. Functional magnetic resonance imaging (fMRI) studies during episodic memory encoding have demonstrated repetition suppression in the hippocampus and this reduction has been linked to successful memory formation. An emerging body of functional imaging evidence suggests that the posteromedial cortex, in addition to the medial temporal lobes, may have a pivotal role in successful episodic memory. This area typically deactivates during initial memory encoding, but its functional changes in response to repetitive encoding remain poorly specified. Here, we investigate the repetition‐related changes in the posteromedial cortex as well as the hippocampus while the participants underwent an fMRI experiment involving repetitive encoding of face–name pairs. During the first encoding trial of face–name pairs, significant activation in the hippocampus was observed. The second and third encoding trials demonstrated a repetition suppression effect in the hippocampus, indicated by a stepwise decrease of activation. In contrast, the posteromedial cortex demonstrated significant deactivation during the initial encoding trial of face–name pairs. The second and third encoding trials demonstrated a stepwise decrease of deactivation, repetition enhancement, with activity at or above baseline levels in the final encoding trial. These findings demonstrate that hippocampus repetition suppression as well as posteromedial repetition enhancement is related to successful encoding processes and are discussed in relation to the default mode hypothesis as well as potential implications for understanding late‐life amnestic disorders. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.
Olefination Reactions in the Synthesis of Cyclophanes
Authors: Bodwell Graham J. , Nandaluru Penchal Reddy
Published: February 2012

A survey of olefination reactions that have been used in the synthesis of cyclophanes is presented. This covers the Ramberg–Bäcklund reaction, the Wittig and related reactions, the McMurry and related reactions, ring‐closing metathesis (alkenes, alkynes and ene‐ynes), aldol condensations and Siegrist reactions, as well as miscellaneous reactions. The McMurry reaction and ring‐closing metathesis have enjoyed the greatest popularity in recent years, but they are typically used for complementary purposes. In virtually all cases, the McMurry reaction is used to install a two‐carbon (1,2‐ethenylene) bridge, whereas ring‐closing metathesis is used to construct bridges that are at least four‐membered, but usually considerably longer. Some well‐known olefinations have seen little or no use in the field of cyclophane chemistry.
Integrative genomics: Liver regeneration and hepatocellular carcinoma
Authors: Coban Zeynep , Barton Michelle Craig
Published: February 2012

Numerous genome wide profiles of gene expression changes in human hepatocellular carcinoma (HCC), compared to normal liver tissue, have been reported. Hierarchical clustering of these data reveal distinct patterns, which underscore conservation between human disease and mouse models of HCC, as well as suggest specific classification of subtypes within the heterogeneous disease of HCC. Global profiling of gene expression in mouse liver, challenged by partial hepatectomy to regenerate, reveals alterations in gene expression that occur in response to acute injury, inflammation, and re‐entry into cell cycle. When we integrated datasets of gene expression changes in mouse models of HCC and those that are altered at specific times of liver regeneration, we saw shared, conserved alterations in gene expression within specific biological pathways, both up‐regulated, for example, cell cycle, cell death, and cellular development, or down‐regulated, for example, vitamin and mineral metabolism, lipid metabolism, and molecular transport. Additional molecular mechanisms shared by liver regeneration and HCC, as yet undiscovered, may have important implications in tumor development and recurrence. These comparisons may offer a way to judge how liver resection, in the treatment of HCC, introduces challenges to care of the disease. Further, uncovering the pathways conserved in inflammatory response, hypertrophy, proliferation, and architectural remodeling of the liver, which are shared in liver regeneration and HCC, versus those specific to tumor development and progression in HCC, may reveal new biomarkers or potential therapeutic targets in HCC. J. Cell. Biochem. 113: 2179–2184, 2012. © 2012 Wiley Periodicals, Inc.
Is using work–life interface benefits a career‐limiting move? An examination of women, men, lone parents, and parents with partners
Authors: Konrad Alison M. , Yang Yang
Published: February 2012

Using a large national sample based on Workplace and Employee Survey data collected by Statistics Canada in 2001 and 2002, we examined the effects of employee usage of seven organizational work–life interface benefits on promotions. Analysis predicted promotions in 2002 when number of promotions received by 2001 were controlled. The main effect of using work–life interface benefits on promotions was positive, indicating that using these benefits is not a career‐limiting move. Gender, presence of young children, and marital status interacted with the use of work–life interface benefits. Single parents benefitted less than other employees from using work–life interface options. Altogether, these findings suggest that the ongoing positive effects of conservation of time and energy resources for employees outweigh the initial short‐term negative effects of signaling and stigmatization. Copyright © 2012 John Wiley & Sons, Ltd.
The impacts of the PNA and NAO on annual maximum snowpack over southern Canada during 1979–2009
Authors: Zhao Hongxu , Higuchi Kaz , Waller James , Auld Heather , Mote Thomas
Published: February 2012

The Pacific/North American pattern (PNA) and North Atlantic Oscillation (NAO) are two of the most important atmospheric low‐frequency variability modes modulating interannual anomalies of snowpacks in North America. However, the quantitative degree to which the PNA and NAO affect the annual maximum snow water equivalent (SWEmax), a quantity directly relevant to the ground snow load calculation in National Building Code of Canada, remains unknown. This study explores the relationship of the winter PNA and NAO to the Canadian SWEmax anomalies and potential changes associated with atmospheric circulation patterns. Significant correlations are identified in eastern and western Canada, where climatological mean values are largest due to the high frequency of snow storm occurrence. The regions in Canada where SWEmax anomalies are influenced by the PNA and NAO experienced a significant change from pre‐1998 to post‐1998. This change is consistent with the observed changes in annual maximum snow depth and the winter atmospheric circulations during 1979–2009. Copyright © 2012 Royal Meteorological Society
Knowledge‐based changes in turbulent environments: categories and effects on value creation
Authors: Ciao Biagio
Published: February 2012

A continuous and radical change creates value if heterogeneous competences and research fields are mixed, whereas episodic changes are expensive and dangerous.
Bringing ICT to the strategy table
Authors: Stace Doug , Courtney Nigel , Holtham Clive
Published: February 2012

Information and communication technologies (ICTs) may assist key decision‐making when defining business strategies.
Relationship between sleep problems and health-related quality of life among pediatric liver transplant recipients
Authors: Fredericks Emily M. , Dore-Stites Dawn , Calderon Sheyla Y. , Well Andrew , Eder Sally J. , Magee John C. , Lopez James M.
Published: February 2012

Among adult liver transplant recipients (LTRs), sleep disturbances and fatigue are common. Sleep problems following pediatric liver transplantation may contribute to daytime fatigue and lower health-related quality of life (HRQOL). The aim of this cross-sectional study was to determine the impact of sleep problems on the HRQOL of pediatric LTRs using validated measures. Participants included 47 LTRs. Mean age of the LTRs was 10.9 ± 4.6 years, and mean time since transplantation was 6.2 ± 3.9 years. The primary indication for transplantation was biliary atresia (51%). According to parent reports, pediatric transplant recipients had symptoms of sleep-disordered breathing, excessive daytime sleepiness, daytime behavior problems, and restless legs; 40.4% of parents and 43.8% of children reported significantly lower total HRQOL for the recipients. Age, time since transplantation, and health status were not significantly related to the quality of life. Hierarchical regression analyses revealed that the sleep-disordered breathing subscale of the Pediatric Sleep Questionnaire accounted for significant variance in parent-proxy reports on the Pediatric Quality of Life (PedsQL) summary scales measuring children's psychosocial health (R
2 = 0.36, P < 0.001), physical health (R
2 = 0.19, P = 0.004), and total HRQOL (R
2 = 0.35, P < 0.001). Also, the sleep-disordered breathing subscale accounted for significant variance in the child self-reported school functioning scale (R
2 = 0.18, P = 0.03). Clinically significant sleep problems were more common among children with low total HRQOL. In conclusion, sleep problems were common in this cohort of pediatric LTRs and predicted significant variance in HRQOL. Prospective larger scale studies are needed to assess factors that contribute to sleep difficulties and low HRQOL in this population. The detection and treatment of significant sleep problems may benefit the HRQOL of pediatric LTRs.
Pregnancy outcomes of liver transplant recipients: A systematic review and meta-analysis
Authors: Deshpande Neha A. , James Nathan T. , Kucirka Lauren M. , Boyarsky Brian J. , Garonzik-Wang Jacqueline M. , Cameron Andrew M. , Singer Andrew L. , Dagher Nabil N. , Segev Dorry L.
Published: February 2012

Approximately 14,000 women of reproductive age are currently living in the United States after liver transplantation (LT), and another 500 undergo LT each year. Although LT improves reproductive function in women with advanced liver disease, the associated pregnancy outcomes and maternal-fetal risks have not been quantified in a broad manner. To obtain more generalizable inferences, we performed a systematic review and meta-analysis of articles that were published between 2000 and 2011 and reported pregnancy-related outcomes for LT recipients. Eight of 578 unique studies met the inclusion criteria, and these studies represented 450 pregnancies in 306 LT recipients. The post-LT live birth rate [76.9%, 95% confidence interval (CI) = 72.7%-80.7%] was higher than the live birth rate for the US general population (66.7%) but was similar to the post–kidney transplantation (KT) live birth rate (73.5%). The post-LT miscarriage rate (15.6%, 95% CI = 12.3%-19.2%) was lower than the miscarriage rate for the general population (17.1%) but was similar to the post-KT miscarriage rate (14.0%). The rates of pre-eclampsia (21.9%, 95% CI = 17.7%-26.4%), cesarean section delivery (44.6%, 95% CI = 39.2%-50.1%), and preterm delivery (39.4%, 95% CI = 33.1%-46.0%) were higher than the rates for the US general population (3.8%, 31.9%, and 12.5%, respectively) but lower than the post-KT rates (27.0%, 56.9%, and 45.6%, respectively). Both the mean gestational age and the mean birth weight were significantly greater (P < 0.001) for LT recipients versus KT recipients (36.5 versus 35.6 weeks and 2866 versus 2420 g). Although pregnancy after LT is feasible, the complication rates are relatively high and should be considered during patient counseling and clinical decision making. More case and center reports are necessary so that information on post-LT pregnancy outcomes and complications can be gathered to improve the clinical management of pregnant LT recipients. Continued reporting to active registries is highly encouraged at the center level.
Novel Peptide‐Shelled Dendrimer with Dramatically Changeable Thermo‐Responsive Character
Authors: Koga Tomoyuki , Iimura Masayuki , Higashi Nobuyuki
Published: February 2012

The preparation of a novel peptide/dendrimer hybrid is reported in which an elastin‐like oligopeptide is successfully assembled onto a poly(amidoamine) dendrimer surface (G4‐ELP), and its unique thermo‐responsive behavior is discussed. As a result, the G4‐ELP is found to exhibit LCST behavior in the pH range 3–10 including physiological temperature range under neutral‐pH conditions. Moreover, cooperative interplay between the folding state of the ELP shell and the ionization state of the dendrimer core enables the G4‐ELP to control its LCST widely by pH variation. This achievement provides a new insight for the design of dual‐responsive materials with a potential in biological applications.

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Higher susceptibility of spontaneous and NNK‐induced lung neoplasms in connexin 43 deficient CD1 × AJ F1 mice: Paradoxical expression of connexin 43 during lung carcinogenesis
Authors: Fukumasu Heidge , Avanzo Jose L. , Sanches Daniel S. , Mennecier Gregory , Mori Claudia M.C. , Dagli Maria L. Z.
Published: February 2012

Connexins (Cxs) are proteins that form the communicating gap junctions, and reportedly have a role in carcinogenesis. Here, we evaluated the importance of Connexin43 (Cx43) in spontaneous and 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanone (NNK)‐induced lung carcinogenesis. Male wild‐type (Cx43+/+) and hemizygote (Cx43+/−) CD1 × AJ F1 mice were injected with NNK or saline. After 60 weeks mice were euthanized; lung nodules were counted, measured, and fixed in formalin or snap frozen. Immunohistochemistry for Cx43 and Beta‐catenin (β‐catenin) was performed and Cx43 mRNA expression was evaluated by real‐time PCR. Cx43 deletion significantly increased the incidence and number of spontaneous nodules in the CD1 × AJ F1 mice and the number of gross lesions and the aggressiveness of lesions in NNK‐treated mice. Cx43 mRNA increased significantly and was correlated with the aggressiveness of tumors, although lesions from Cx43+/− mice expressed less Cx43 RNAm than their counterparts. Lung parenchyma presented a Cx43 immunostaining pattern with points or plaques between cells. In hyperplasias and adenomas, Cx43 was found in the membrane and in cytoplasm. Malignant lesions presented increased Cx43 in cytoplasm and a few membrane spots of immunostaining. β‐catenin was weakly expressed in lung parenchyma. Though hyperplasias presented some cells with nuclear β‐catenin, NNK‐induced tumors contained a higher number of this staining pattern. Also, no difference in β‐catenin occurred between both genotypes independently of the histological grade. In summary, our results indicate that Cx43 acts as a tumor suppressor gene in early lung tumorigenesis and loses this property in advanced carcinogenesis. Therefore, Cxs are better classified as conditional tumor suppressors. © 2012 Wiley Periodicals, Inc.
Debating Immortality: Application of Data Envelopment Analysis to Voting for the Baseball Hall of Fame
Authors: Miceli Thomas J. , Volz Brian D.
Published: February 2012

This paper applies data envelopment analysis to voting for the Baseball Hall of Fame (HOF). The approach interprets a player's career statistics as inputs and the percentage of votes that he received for the HOF as the output. A constructed frontier based on past voting defines the maximum number of votes that a player should receive based on his statistical profile. Our results suggest that about a third of the current members of the HOF (excluding Negro League players, managers, umpires, and executives) should be replaced by more deserving players. Our conclusions, however, do not account for those aspects of a player's career (both positive and negative) not captured by statistics. Copyright © 2012 John Wiley & Sons, Ltd.
Rat brain MRI at 16.4T using a capacitively tunable patch antenna in combination with a receive array
Authors: Shajan G. , Hoffmann Jens , Balla Dávid Z. , Deelchand Dinesh K. , Scheffler Klaus , Pohmann Rolf
Published: February 2012

For MRI at 16.4T, with a proton Larmor frequency of 698 MHz, one of the principal RF engineering challenges is to generate a spatially homogeneous transmit field over a larger volume of interest for spin excitation. Constructing volume coils large enough to house a receive array along with the subject and to maintain the quadrature symmetry for different loading conditions is difficult at this frequency. This calls for new approaches to RF coil design for ultra‐high field MR systems. A remotely placed capacitively tunable patch antenna, which can easily be adjusted to different loading conditions, was used to generate a relatively homogeneous excitation field covering a large imaging volume with a transversal profile similar to that of a birdcage coil. Since it was placed in front of the animal, this created valuable free space in the narrow magnet bore around the subject for additional hardware. To enhance the reception sensitivity, the patch antenna was combined with an actively detunable 3‐channel receive coil array. In addition to increased SNR compared to a quadrature transceive surface coil, we were able to get high quality gradient echo and spin‐echo images covering the whole rat brain. Copyright © 2012 John Wiley & Sons, Ltd.
Continuous infrared‐assisted double‐sided roll‐to‐roll embossing of flexible polymer substrates
Authors: Liu Shih‐Jung , Huang Chun‐Chieh , Liao Che‐Ting
Published: February 2012

This article reports a novel infrared (IR)‐assisted roll‐to‐roll embossing method, which enables the replication of microfeatures onto the surfaces of flexible polymer substrates. An IR‐assisted roll‐to‐roll embossing facility was designed and built in our laboratory especially for this study. Metallic rollers bearing micropatterns of two different feature sizes, namely 150 and 20 μm in depth, were employed. The former one was prepared by microelectric discharge machining the roller, whereas the latter was fabricated by electroplating a thin layer of nickel on the surface of the roller, followed by a diamond turning process to create the microstructures. The embossing facility was used to replicate the microstructure onto polyethylene terephthalate and polycarbonate films in the experiments. During roller embossing, the IR radiation shed on the rollers, and the energy was converted into heat to melt the polymer substrates and to replicate the microstructures. The influence of various processing parameters on the replicability of microfeatures was investigated. Under the proper processing conditions, double‐sided flexible polymer substrates with microstructures could be successfully fabricated. The proposed method shows great potential for fabrication of micro‐optical components due to its simplicity and versatility. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Assessment of parameters influencing fiber characteristics of chitosan nanofiber membrane to optimize fiber mat production
Authors: Areias A.C. , Gómez‐Tejedor J.A. , Sencadas V. , Alió J. , Ribelles J.L. Gómez , Lanceros‐Mendez S.
Published: February 2012

Electrospun chitosan nanofiber mats have been obtained using chitosan solutions in a mixture of trifluoroacetic acid and dichloromethane. The relationship between processing parameters (solvent composition, polymer concentration in the solution, feeding rate, applied voltage, traveling distance between the needle, and the collector) and fiber morphology was studied. Taguchi's methodology was followed to determine which parameters have the strongest influence on mean fiber diameter and fiber homogeneity. Chitosan nanofibers obtained with this procedure were water soluble due to the protonation of amine side groups but were successfully neutralized by immersion in calcium carbonate solutions. It was established that fiber diameter is mainly determined by the solution concentration and the distance from the needle to the collector while other parameters have less influence. The set of parameters that produce the thinnest fibers were a concentration of 8 wt%, a TFA/DCM ratio of 80:20 (v/v%), a voltage of 30 kV, a flow rate of 6.0 mL/h, a gap distance of 10 cm, using a needle diameter of 0.5, allowing to produce randomly oriented mats with a mean fiber thickness of 66 nm. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Carborane‐incorporated poly(silyleneethynylenephenyleneethynylene)s with different side groups
Authors: Wang Canfeng , Jiang Yun , Gao Yu , Zhou Yan , Huang Farong , Du Lei
Published: February 2012

Carborane‐incorporated poly(silyleneethynylenephenyleneethynylene)s with different side groups were synthesized from corresponding poly(silyleneethynylenephenyleneethynylene)s and decaborane (B10H14) in the presence of acetonitrile through in‐situ reaction. The obtained polymers with o‐carborane units were characterized by using Fourier transform infrared and nuclear magnetic resonance spectroscopies, rheological measurements, differential scanning calorimetry, and thermogravimetric analysis. The results show that the properties of these carborane‐incorporated polymers vary with side groups in main chains. They possess good processability and can be crosslinked to form thermosets at temperatures less than 250°C. The thermosets exhibit excellent thermal and thermooxidative stabilities. The weight losses of the thermosets heated to 800°C in air are only 10% approximately. After pyrolysis of the thermosets in nitrogen at 1000°C, the pyrolytic products have no further weight losses up to 1000°C in air. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Effect of fiber modification with a novel compatibilizer on the mechanical properties and water absorption of hemp‐fiber‐reinforced unsaturated polyester composites
Authors: Qiu Renhui , Ren Xiaofeng , Li Kaichang
Published: February 2012

Hemp‐fiber‐reinforced unsaturated polyester (UPE) composites were prepared by compression molding. The treatment of hemp fibers with N‐methylol acrylamide (NMA) and sulfuric acid as a catalyst significantly increased tensile strength, flexural modulus of rupture and flexural modulus of elasticity, and water resistance of the resulting hemp–UPE composites. Fourier transform infrared (FTIR) spectra revealed that some NMA was covalently bonded to hemp fibers. Scanning electronic microscopy graphs of the fractured hemp–UPE composites revealed that treatment of hemp fibers with NMA greatly improved the interfacial adhesion between hemp fibers and UPE. The chemical reactions between hemp fibers and NMA as well as the mechanism of improving the interfacial adhesion were proposed and discussed. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Release evaluation of molecularly imprinted polymers prepared under molecular crowding conditions
Authors: Li Xiao‐Xia , Hao Lan‐Fang , Huang Yan‐Ping , Duan Hong‐Quan , Liu Zhao‐Sheng
Published: February 2012

In this work, molecular crowding agent was first applied to the preparation of molecularly imprinted polymer (MIP)‐based drug release system. With S‐naproxen as template, the MIPs were prepared with methacrylic acid and ethylene glycol dimethacrylate, in the presence of polystyrene as molecular crowding by precipitation polymerization. Morphology and particle size of the resulting MIP sub‐micrometer microparticles were determined by scanning electron microcopy and dynamic light scattering. The influence of several parameters on the sustained release of the imprinted polymers was investigated, including the molar ratio of the imprint molecule to the functional monomers, the molar ratio of the functional monomers to the crosslinking monomers, and the type of the porogen. In addition, the release of the MIP was compared to that of the traditionally prepared imprinted polymers with other porogens. The transport mechanism of template was studied by fitting experiment data with different model equations and calculating the corresponding parameters. The novel MIPs prepared with molecular crowding were able to prolong S‐naproxen, in a phosphate buffers solution of pH 7.4, for more than 12 h, indicating better sustained release effect than that prepared with noncrowding agent. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Effect of dispersion on rheological and mechanical properties of polypropylene/carbon nanotubes nanocomposites
Authors: Zhou Kai , Gu Shu‐Ying , Zhang Yi‐Han , Ren Jie
Published: February 2012

Polypropylene (PP) nanocomposites filled with the pristine multi‐wall carbon nanotubes (CNTs) and the purified CNTs were prepared by melt blending. The microstructure and linear viscoelastic properties wereinvestigated using rheological and morphological measurements. The results show that the purified CNTs disperse uniformly in the PP matrix. At low frequencies, frequency dependence of modulus weakens clearly with the addition of the CNTs, indicating that the long‐range motion of the polymer chains is restrained by the presence of the CNTs. Percolation networks form when the loading levels achieve up to 3 and 1.5 wt% for the composites with the pristine CNTs (PPCNTs) and the purified CNTs (PPcCNTs), respectively. The linear relaxation modulus increases with increasing loading level. And for composites with loading levels above percolation concentration, the modulus appears to reach a plateau at long time scales due to the formation of percolation network. Tensile strength and impact strength are simultaneously improved with the addition of the CNTs. The better the dispersion of the CNTs, the greater the improvement of the tensile strength and the impact strength. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Analysis of benzodiaza‐15‐crown‐5 ether derivative binding properties by potentiometric and optical methods
Authors: Fedorova Olga , Fedorov Yury , Oshchepkov Maxim , Dobrovolskaya Marina
Published: February 2012

This research concerns the analysis of the binding properties of benzodiaza‐15‐crown‐5 ether derivatives towards different metal ions (Mg(II), Cd(II), Ni(II), Cu(II), Zn(II), Pb(II), Hg(II) and Ag(I)) in acetonitrile and water by potentiometric and optical methods. Benzodiaza‐15‐crown‐5 ether demonstrates high binding affinity towards Hg2+ (lg K11 = 12.7), whereas the stability constants of complexes with other studied cations varied from 3 to 6 logarithmic units. Copyright © 2012 John Wiley & Sons, Ltd.
Quadratic nonlinear optical and preliminary piezoelectric investigation of crosslinked samples obtained from a liquid chromophore
Authors: Centore Roberto , Concilio Antonio , Borbone Fabio , Fusco Sandra , Carella Antonio , Roviello Antonio , Stracci Glauco , Gianvito Antonio
Published: February 2012

A push–pull chromophore has been synthesized, which is liquid at room temperature and can be crosslinked owing to the presence of two methacrylate moieties. Thin films of the chromophore have been prepared by spin coating, and they have been simultaneously crosslinked and poled under strong electric field. On the poled crosslinked films, the quadratic nonlinear optical (NLO) characterization was performed through nonresonant second harmonic generation measurements at 1368 nm as the fundamental wavelength, yielding a fairly good d33 value of 46 pm/V, with retention of 80% of that value after 2 months at 85 °C. Following the theoretical issue that the quadratic NLO and piezoelectric tensors of a material have the same symmetry properties, and exploiting the easy processing of the chromophore in the liquid phase, we have prepared poled crosslinked samples of the chromophore suitable for piezoelectric tests that were performed using a commercial piezoceramic sample as the reference. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Public attitudes toward cancer and cancer patients: a national survey in Korea
Authors: Cho Juhee , Smith Katherine , Choi Eun‐Kyung , Kim Im‐Ryung , Chang Yoon‐Jung , Park Hyun‐Young , Guallar Eliseo , Shim Young Mog
Published: February 2012

Background

Regardless of improved survival rate, negative images and myths about cancer still abound. Cancer stigma may reduce patients' life opportunities resulting in social isolation, decreased level of emotional well‐being, and poor health outcomes. This study was aimed to evaluate public attitudes toward cancer and cancer patients and people's willingness to disclose cancer diagnosis in South Korea.

Methods

A cross‐sectional survey was conducted in August and September 2009. A nationally representative sample of 1011 men and women with no history of cancer was recruited. A set of 12 questions grouped into three domains (impossibility of recovery, cancer stereotypes, and discrimination) was used to assess public attitudes toward cancer.

Results

It was found 58.5% of study participants agreed that it is impossible to treat cancer regardless of highly developed medical science, 71.8% agreed that cancer patients would not be able to make contributions to society, and 23.5% agreed that they would avoid working with persons who have cancer. The proportions of people who said that that they would not disclose a cancer diagnosis to family, friends or neighbors, or coworkers were 30.2%, 47.0%, and 50.7%, respectively. Negative attitudes toward cancer were strongly associated with lower willingness to disclose a cancer diagnosis.

Conclusions

Negative attitudes, stereotypes, and discriminating attitudes toward cancer and people affected by the disease were very common in spite of clinical progress and improved survivorship.

Impact

Our findings emphasize the need for health policy and social changes to provide a more supportive environment for cancer survivors. Copyright © 2012 John Wiley & Sons, Ltd.
Frequency Scaling Laws of Plasma Bulk in Atmospheric Radio Frequency Discharges
Authors: Zhang Yuantao T. , Shang Wanli
Published: February 2012

In this paper a modelling study is performed to investigate the frequency scaling laws in atmospheric radio frequency discharges. By introducing the relaxation frequency of discharge plasmas, which links the electron density and excitation frequency, the relationships between excitation frequency and other discharge parameters, such as electron density, current density and sheath thickness, are revealed based on the analytical equations deduced from the model and then confirmed by the computational data. These scalings are effective to give insights into some discharge parameters which are not easily accessible in experiments such as electron density.

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Cell Adhesion to PEEK Treated by Plasma Immersion Ion Implantation and Deposition for Active Medical Implants
Authors: Awaja Firas , Bax Daniel V. , Zhang Shengnan , James Natalie , McKenzie David R.
Published: February 2012

Polyetheretherketone (PEEK) is an attractive material for the encapsulation of active medical implants. PEEK, however, shows hydrophobic surface properties which are not favorable for protein absorption and cell adhesion. We show that oxygen rich nanofilms “sticky thin film,” deposited on PEEK surfaces from plasma using a plasma immersion ion implantation and deposition technique with a (CH4/O2) gas mixture greatly improved cell adhesion (up to 75%) and spreading (up to 81%). Strong correlations were found between cell adhesion and the water contact angle, the polar component of surface energy, and to a lesser extent oxygen concentration of the PEEK surfaces. Surface polarity of the plasma deposited “sticky thin film” was deemed to be the predominant factor in influencing cell adhesion.

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Vacuum‐ultraviolet (VUV) Photo‐polymerization of Amine‐rich Thin Films from Ammonia–Hydrocarbon Gas Mixtures
Authors: Truica‐Marasescu Florina , Ruiz Juan‐Carlos , Wertheimer Michael R.
Published: February 2012

Photo‐induced polymerization of hydrocarbon “monomers”, both unsaturated C2H4 and saturated CH4, has been carried out by vacuum‐ultraviolet (VUV) irradiation of the flowing gases at reduced pressure, employing near‐monochromatic radiation from Kr and Xe lamps. Using mixtures with NH3, the source of bound N in the coatings, similar concentrations, [N], can be achieved in both UV‐PE(M):N and low‐pressure plasma polymers, L‐PPE:N, but the former are much richer in primary amines, with selectivity values ([NH2]/[N]) up to 75%. UV‐PE:N and UV‐PM:N films prepared with gas mixture ratios, R, between 0.75 and 1.0 possess the main characteristics required for bio‐technological applications: (i) NH2‐rich, (ii) low loss of [NH2] upon exposure to atmosphere or water, and (iii) very low solubility in aggressive solvents, e.g., water. The VUV photo‐polymerization process, governed by reactions of free radicals from the gas‐phase, appears to result in more stable, more densely cross‐linked deposits than those from plasma‐assisted processes.

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A work process for revalidating LOPAs and other risk analyses
Authors: Wagner Tim , Champion John
Published: February 2012

The chemical process industry has long recognized the necessity of periodically revalidating process hazard analyses (PHAs), such as hazard and operability studies and What‐if analyses. Center for Chemical Process Safety (CCPS) has published a book which describes this work process titled Revalidating PHAs [1]. However, there is limited guidance for revalidating supplemental risk analyses, such as layer of protection analyses (LOPAs), quantitative risk assessments (QRAs), and fault‐tree analyses. The objectives of performing periodic revalidations are to address the cumulative changes in risk that occur over time and to continuously improve our understanding of that risk. Ultimately the goal is to avoid incidents.

An objective revalidation is focused primarily on safety, whereas a project review focuses on many other aspects beyond safety, such as productivity and efficiency. The revalidation is generally more effective at reviewing the external factors that impact the results of an assessment. By revalidating a risk analysis, the team takes a holistic approach to analyzing factors that affect risk to surrounding people or the environment imposed by the continued operation of the facility. Particular focus is placed on changes that impacted the analysis, but may not have been recognized or fully addressed in the management of change review. Some of these external factors include population changes, culture and organizational changes, changes and improvements in the risk analysis methodology and discovery of conflicting data.

This article introduces a work process for revalidating various types of risk analyses and discusses many of the factors that need to be considered. This improves the quality of the revalidation while reducing the overall effort expended. The primary discussion centers on revalidating LOPAs, but other types of studies are discussed as well. Case studies and experiences from actual revalidation efforts are incorporated into the discussion. © 2011 American Institute of Chemical Engineers Process Saf Prog, 2011
Joint analysis of bivariate longitudinal ordinal outcomes and competing risks survival times with nonparametric distributions for random effects
Authors: Li Ning , Elashoff Robert M. , Li Gang , Tseng Chi-Hong
Published: February 2012

We propose a semiparametric joint model for bivariate longitudinal ordinal outcomes and competing risks failure time data. The association between the longitudinal and survival endpoints is captured by latent random effects. This approach generalizes previous joint analysis that considers only one response variable at the longitudinal endpoint. One unique feature of the proposed model is that we relax the commonly used normality assumption for random effects and leave the distribution completely unspecified. We use a modified version of the vertex exchange method in conjunction with an expectation–maximization algorithm to estimate the random effects distribution and model parameters. We show via simulations that robust parameter estimates are obtained from the proposed method under various scenarios. We illustrate the approach using cough severity and frequency data from a scleroderma lung study. Copyright © 2012 John Wiley & Sons, Ltd.
Quantifying discrimination of Framingham risk functions with different survival C statistics
Authors: Pencina Michael J. , D'Agostino Ralph B. , Song Linye
Published: February 2012

Cardiovascular risk prediction functions offer an important diagnostic tool for clinicians and patients themselves. They are usually constructed with the use of parametric or semi‐parametric survival regression models. It is essential to be able to evaluate the performance of these models, preferably with summaries that offer natural and intuitive interpretations. The concept of discrimination, popular in the logistic regression context, has been extended to survival analysis. However, the extension is not unique. In this paper, we define discrimination in survival analysis as the model's ability to separate those with longer event‐free survival from those with shorter event‐free survival within some time horizon of interest. This definition remains consistent with that used in logistic regression, in the sense that it assesses how well the model‐based predictions match the observed data. Practical and conceptual examples and numerical simulations are employed to examine four C statistics proposed in the literature to evaluate the performance of survival models. We observe that they differ in the numerical values and aspects of discrimination that they capture. We conclude that the index proposed by Harrell is the most appropriate to capture discrimination described by the above definition. We suggest researchers report which C statistic they are using, provide a rationale for their selection, and be aware that comparing different indices across studies may not be meaningful. Copyright © 2012 John Wiley & Sons, Ltd.