bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Supramolecular “Double‐Cable” Structure with a 12944 Helix in a Columnar Porphyrin‐C60 Dyad and its Application in Polymer Solar Cells
Authors: Wang Chien‐Lung , Zhang Wen‐Bin , Sun Hao‐Jan , Van Horn Ryan M. , Kulkarni Rahul R. , Tsai Chi‐Chun , Hsu Chain‐Shu , Lotz Bernard , Gong Xiong , Cheng Stephen Z. D. 
Published: May 2012

AbstractA novel porphyrin‐C60 dyad (PCD1) is designed and synthesized to investigate and manipulate the supramolecular structure where geometrically isotropic [such as [60]fullerene (C60)] and anisotropic [such as porphyrin (Por)] units coexist. It is observed that PCD1 possesses an enantiomeric phase behavior. The melting temperature of the stable PCD1 thermotropic phase is 160 °C with a latent heat (ΔH) of 18.5 kJ mol−1. The phase formation is majorly driven by the cooperative intermolecular Por–Por and C60–C60 interactions. Structural analysis reveals that this stable phase possesses a supramolecular “double‐cable” structure with one p‐type Por core columnar channel and three helical n‐type C60 peripheral channels. These “double‐cable” columns further pack into a hexagonal lattice with a = b = 4.65 nm, c = 41.3 nm, α = β = 90°, and γ = 120°. The column repeat unit is determined to possess a 12944 helix. With both donor (D; Pro) and acceptor (A; C60) units having their own connecting channels as well as the large D/A interface within the supramolecular “double‐cable” structure, PCD1 has photogenerated carriers with longer lifetimes compared to the conventional electron acceptor [6,6]‐phenyl‐C61‐butyric acid methyl ester. A phase‐separated columnar morphology is observed in a bulk‐heterojunction (BHJ) material made by the physical blend of a low band‐gap conjugated polymer, [poly[2,6‐(4,4‐bis‐(2‐ethylhexyl)‐4H‐cyclopenta [2,1‐b;3,4‐b′]‐dithiophene)‐alt‐4,7‐(2,1,3‐benzothia‐diazole)] (PCPDTBT), and PCD1. With a specific phase structure in the solid state and in the blend, PCD1 is shown to be a promising candidate as a new electron acceptor in high performance BHJ polymer solar cells.
An Alternative Ionic Conductivity Mechanism for Plastic Crystalline Salt–Lithium Salt Electrolyte Mixtures
Authors: Henderson Wesley A. , Seo Daniel M. , Zhou Qian , Boyle Paul D. , Shin Joon‐Ho , De Long Hugh C. , Trulove Paul C. , Passerini Stefano 
Published: May 2012

AbstractThe phase behavior and ionic conductivity of tetraethylammonium bis(trifluoromethane‐sulfonyl)imide (Et4NTFSI) salt mixtures with LiTFSI have been examined. In addition, the phase behavior and crystal structure of neat LiTFSI is also reported. Two (1‐x) Et4NTFSI‐(x) LiTFSI (x = 0.50 and 0.67, where x is the mol fraction) mixed‐salt crystalline phases form. Large variations in ionic conductivity are observed; these are attributed to solid‐solid phase transitions of the neat Et4NTFSI salt creating disordered plastic crystalline phases and the formation of a low‐melting eutectic composition between the neat Et4NTFSI salt and the 1/1 Et4NTFSI/LiTFSI (x = 0.50) phase. Although Et4NTFSI and LiTFSI melt at 102 and 234 °C, respectively, the two salts form a eutectic system with a melting temperature of 32 °C. Based upon the findings reported, a new conductivity mechanism is proposed for plastic crystalline salt‐lithium salt electrolytes which is not ascribed to solid‐state diffusion/conduction.
Reduced systemic bicyclo‐prostaglandin‐E2 and cyclooxygenase‐2 gene expression are associated with inefficient erythropoiesis and enhanced uptake of monocytic hemozoin in children with severe malarial anemia
Authors: Anyona Samuel B. , Kempaiah Prakasha , Raballah Evans , Davenport Gregory C. , Were Tom , Konah Stephen N. , Vulule John M. , Hittner James B. , Gichuki Charity W. , Ong'echa John M. , Perkins Douglas J. 
Published: May 2012

AbstractIn holoendemic Plasmodium falciparum transmission areas, severe malaria primarily occurs in children aged <48 months and manifests as severe malarial anemia [SMA; hemoglobin (Hb) < 6.0 g/dL]. Induction of high levels of prostaglandin‐E2 (PGE2) through inducible cyclooxygenase‐2 (COX‐2) is an important host‐defense mechanism against invading pathogens. We have previously shown that COX‐2‐derived PGE2 levels are reduced in children residing in hyperendemic transmission regions with cerebral malaria and in those with mixed sequelae of anemia and hyperparasitemia. Our in vitro studies further demonstrated that reduced PGE2 was due to downregulation of COX‐2 gene products following phagocytosis of malarial pigment (hemozoin, PfHz). However, as COX‐2‐PGE2 pathways and the impact of naturally acquired PfHz on erythropoietic responses have not been determined in children with SMA, plasma and urinary bicyclo‐PGE2/creatinine and leukocytic COX‐2 transcripts were determined in parasitized children (<36 months) stratified into SMA (n = 36) and non‐SMA (Hb ≥ 6.0 g/dL; n = 38). Children with SMA had significantly reduced plasma (P = 0.001) and urinary (P < 0.001) bicyclo‐PGE2/creatinine and COX‐2 transcripts (P = 0.007). There was a significant positive association between Hb and both plasma (r = 0.363, P = 0.002) and urinary (r = 0.500, P = 0.001)] bicyclo‐PGE2/creatinine. Furthermore, decreased systemic bicyclo‐PGE2/creatinine was associated with inefficient erythropoiesis (i.e., reticulocyte production index; RPI < 2.0, P = 0.026). Additional analyses demonstrated that plasma (P = 0.031) and urinary (P = 0.070) bicyclo‐PGE2/creatinine and COX‐2 transcripts (P = 0.026) progressively declined with increasing concentrations of naturally acquired PfHz by monocytes. Results presented here support a model in which reduced COX‐2‐derived PGE2, driven in part by naturally acquired PfHz by monocytes, promotes decreased erythropoietic responses in children with SMA. Am. J. Hematol., 2012. © 2012 Wiley Periodicals, Inc.
Ethnic differences in the accumulation of fat and lean mass in late gestation
Authors: Lampl Michelle , Lee Wesley , Koo Winston , Frongillo Edward A. , Barker David J.P. , Romero Roberto 
Published: May 2012

AbstractObjectives:Lower birth weight within the normal range predicts adult chronic diseases, but the same birth weight in different ethnic groups may reflect different patterns of tissue development. Neonatal body composition was investigated among non‐Hispanic Caucasians and African Americans, taking advantage of variability in gestational duration to understand growth during late gestation.Methods:Air displacement plethysmography assessed fat and lean body mass among 220 non‐Hispanic Caucasian and 93 non‐Hispanic African American neonates. The two ethnic groups were compared using linear regression.Results:At 36 weeks of gestation, the average lean mass of Caucasian neonates was 2,515 g vs. that of 2,319 g of African American neonates (difference, P = 0.02). The corresponding figures for fat mass were 231 and 278 g, respectively (difference, P = 0.24). At 41 weeks, the Caucasians were 319 g heavier in lean body mass (P < 0.001) but were also 123 g heavier in fat mass (P = 0.001). The slopes for lean mass vs. gestational week were similar, but the slope of fat mass was 5.8 times greater (P = 0.009) for Caucasian (41.0 g/week) than for African American neonates (7.0 g/week).Conclusions:By 36 weeks of gestation, the African American fetus developed similar fat mass and less lean mass compared with the Caucasian fetus. Thereafter, changes in lean mass among the African American fetus with increasing gestational age at birth were similar to the Caucasian fetus, but fat accumulated more slowly. We hypothesize that different ethnic fetal growth strategies involving body composition may contribute to ethnic health disparities in later life. Am. J. Hum. Biol. 2012. © 2012 Wiley Periodicals, Inc.
A new estimate of the impact of OSHA inspections on manufacturing injury rates, 1998–2005
Authors: Haviland Amelia M. , Burns Rachel M. , Gray Wayne B. , Ruder Teague , Mendeloff John 
Published: May 2012

AbstractBackgroundA prior study indicated that the effect of OSHA inspections on lost workday injuries had declined from 1979 through 1998. This study provides an updated estimate for 1998–2005.MethodsInjury data from the Pennsylvania workers' compensation program were linked with employment data from unemployment compensation records to calculate lost‐time rates for single‐establishment manufacturing firms with more than 10 employees. These rates were linked to OSHA inspection findings. The RAND Human Subjects Protection Committee determined that this study was exempt from reviewResultsInspections with penalties reduced injuries by an average of 19–24% annually in the 2 years following the inspection. These effects were not found for workplaces with fewer than 20 or more than 250 employees or for inspections without penalties.ConclusionsThese findings should be generalizable to the 29 states where federal OSHA directly enforces standards. They suggest that the impact of inspections has increased from the 1990s. Am. J. Ind. Med. 55:964–975, 2012. © 2012 Wiley Periodicals, Inc.
Hereditary hemorrhagic telangiectasia–related epistaxis: innovations in understanding and management
Authors: Sautter Nathan B. , Smith Timothy L. 
Published: May 2012

AbstractBackground:Epistaxis is the most common manifestation of hereditary hemorrhagic telangiectasia (HHT), affecting approximately 90% of patients at some point during their lifetime. Bleeding is chronic and varies from mild, self‐limited episodes to severe, transfusion‐dependent or life‐threatening epistaxis. Treatment options vary from conservative, nonsurgical management to more aggressive surgical approaches. A number of treatment options have been introduced in recent years. There is little consensus in the literature regarding treatment algorithms. The objective of this investigation was to provide a contemporary review of HHT‐related epistaxis, including pathophysiology, disease manifestations, and state‐of‐the‐art treatment modalities.Methods:A systematic review of the literature for HHT‐related epistaxis was performed using the search terms “hereditary hemorrhagic telangiectasia” and “epistaxis.” Additional literature search regarding current recommendations for HHT evaluation and recent developments in genetic mechanisms, pathophysiology, and treatment of HHT was also performed.Results:A total of 308 articles were identified and reviewed for appropriateness of inclusion whereas 64 articles met inclusion criteria. Treatment options range from topical and hormonal therapy to more aggressive surgical modalities. Most treatment descriptions are case series, with few randomized controlled trials. A number of new and novel therapies have been introduced in recent years.Conclusion:HHT is a heterogeneous disease requiring multidisciplinary evaluation and treatment. Therapeutic options for HHT‐related epistaxis vary from conservative, nonsurgical measures to more aggressive surgical treatments. A graduated treatment plan is recommended. Patients present with a wide degree in variation of severity of epistaxis, and treatment is best tailored to the individual patient. ©2012 ARSAAOA, LLC.
Corticosteroid nasal irrigations after endoscopic sinus surgery in the management of chronic rhinosinusitis
Authors: Snidvongs Kornkiat , Pratt Eleanor , Chin David , Sacks Raymond , Earls Peter , Harvey Richard J. 
Published: May 2012

AbstractBackground:Inflammatory dysfunction is considered an important part of chronic rhinosinusitis (CRS). Corticosteroid therapy has been widely used in CRS. Effective topical delivery has been previously problematic. The post–endoscopic sinus surgery (ESS) corridor is essential for adequate topical drug access. Devices delivering large volume with positive pressure allow better distribution to sinus mucosa. The objective of this study is to evaluate the efficacy of postoperative topical sinonasal steroid irrigations for CRS.Methods:Patients with CRS undergoing ESS after failing previous medical therapy were recruited. Structured histopathology including markers of eosinophilia was performed. After surgery, patients received either budesonide 1 mg or betamethasone 1 mg delivered in a 240‐mL squeeze bottle daily. Outcomes of the symptom score, Sino‐Nasal Outcome Test 22 (SNOT‐22) score, and endoscopy score were recorded.Results:A total of 111 patients (mean 50.1 ± 13.5 standard deviation [SD] years, 40.5% female) were included. Mean follow‐up was 55.5 ± 33.9 weeks. Baseline and posttreatment symptom scores (2.6 ± 1.1 vs 1.2 ± 1.0), SNOT‐22 scores (2.2 ± 1.1 vs 1.0 ± 0.8), and endoscopy scores (6.7 ± 3.0 vs 2.5 ± 2.0) revealed significant improvement (all, p < 0.001). Contrary to previous publications, patients with high tissue eosinophilia (>10/high power field [HPF]) had significantly more improvement on symptom score (1.9 ± 1.4 vs 1.1 ± 1.0, p = 0.04), SNOT‐22 score (1.6 ± 1.3 vs 1.0 ± 0.8, p = 0.03), and endoscopy score (5.12 ± 3.4 vs 3.06 ± 3.0, p = 0.01) than those without.Conclusion:The philosophical approach to ESS in CRS is evolving. Topical therapies, when used appropriately, are highly effective for the most challenging eosinophilic patients. Although corticosteroid is a nonspecific therapy, it is effective when appropriately delivered. ©2012 ARSAAOA, LLC.
Effect of process conditions on the dart impact properties of thin‐wall injection‐molded polycarbonate plates
Authors: Moon Jong‐Sin , Lee Jeong‐Moo , Lee Shi‐Ho , Choi Byoung‐Ho 
Published: May 2012

AbstractMultifunctional mobile products, such as cellular phones, laptop computers, personal media players, etc., have become smaller and lighter; so the technology of thin‐wall injection molding (TWIM) has been highlighted for making lightweight and compact mobile electronic products. Regarding mechanical properties, many portable electronic products should pass the so‐called “drop test”; therefore, the evaluation of the dart (or impact) property of the housing that is made by the TWIM process is crucial for commercializing a product. However, extant research on the effect of injection molding process parameters on the physical properties of TWIM plates is insufficient as yet. Therefore, in this study, the pressure and temperature inside the cavity during the injection molding process are monitored by varying the injection molding process parameters, i.e., the gate size, injection speed, and melt temperature, and the effect of the average flow rate of the molten resin inside the cavity on the dart property of thin‐wall injection‐molded plates is examined. The dart property of thin‐wall injection‐molded plates is evaluated by the instrumented dart impact test to differentiate various responses of the load‐displacement data during dart tests. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci., 2013
Scaffolds based on hydroxypropyl starch: Processing, morphology, characterization, and biological behavior
Authors: Silva Itziar , Gurruchaga Mariló , Goñi Isabel , Fernández‐Gutiérrez Mar , Vázquez Blanca , Román Julo San 
Published: May 2012

AbstractIn this study, a novel electrospun hybrid scaffold was developed, which consists of a blend of a modified natural substance, hydroxypropyl starch (HPS) with a synthetic one, poly(ethylene oxide) (PEO). Nanofibers with varying polysaccharide contents were fabricated using water as solvent and the electrospinning process conditions investigated as a function of the weight ratio of the blend. The fibers were characterized through mean diameter and morphology by scanning electron microscopy. Micrographs clearly showed the effect of HPS/PEO weight ratio of the blend on the nanofibers formation. Stability of the fibers was enhanced by coating with hydrophobic poly(methyl methacrylate) (PMMA). In vitro degradation analysis of the coated mats after 1 month of immersion showed porous formation, whereas the fibrous structure was retained. The biological response of the mats against human fibroblasts proved that cells were able to adhere to and proliferate on the fibrous materials. Thus, the feasibility of producing nanofibers of HPS/PEO blends with high proportion of starch and their biocompatibility after coating with PMMA was demonstrated, indicating that these materials have potential to be used as scaffolds in tissue engineering applications. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci., 2013
Sustainable bioderived polymeric materials and thermoplastic blends made from floating aquatic macrophytes such as “duckweed”
Authors: Zeller Mark Ashton , Hunt Ryan , Sharma Suraj 
Published: May 2012

AbstractWhile plastics offer many conveniences to modern consumers, they represent unsustainable practices that hinder economic growth and environmental stability. Therefore, the production of biodegradable plastic from alternative feedstocks is investigated to replace conventional plastics in packaging and short‐term use markets. Duckweed represents a feedstock that elicits high biomass productivity, plus a wastewater remediation potential. To establish duckweed's potential for plastic production this study investigates the stability and thermal characteristics of plasticized and blended duckweed polymers. Duckweed biomass milled to 250 μm was plasticized using glycerol and compression molded into plastic samples. Results indicated a 3 : 1 ratio of duckweed to glycerol produced the best polymer stability. This ratio was then used to develop blends which demonstrated dispersion in biobased or polyethylene (PE) phase, except for 50% Biobased/50% PE where phase continuity was observed. Furthermore, surface morphology indicated limited homogeneity in blends and increased PE was correlated to temperature stability of biobased phase. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci. 2013
Synthesis, characterization, and self‐assembly of amphiphilic fluorinated gradient copolymer
Authors: Chen Yanjun , Zhang Yuying , Wang Yifeng , Sun Chong , Zhang Chaocan 
Published: May 2012

AbstractAn amphiphilic copolymer of acrylic acid (AA) and 2,2,2‐trifluoroethyl methacrylate (TFEMA) was synthesized by reversible addition‐fragmentation transfer (RAFT) copolymerization, using a feed method for adding TFEMA. The kinetics of the RAFT copolymerization agreed well with those characteristic of a first‐order reaction and the molecular weight of copolymers increased with the conversion increasing, both demonstrating that it proceeded in a controlled polymerization manner. Optimal copolymerization was achieved when the reaction was conducted at 70°C, using a molar ratio of TFEMA : AA : RAFT agent : initiator of 400 : 400 : 4 : 1. Analysis of instantaneous 1H‐NMR results proved that the obtained copolymer had a chain structure with AA segments gradually changing to TFEMA segments. The copolymer films had lower surface free energies and slightly microphase separation structures. The amphiphilic copolymer with gradient structures could self‐assemble to form aggregates in selective solvents. The type and composition of solvent mixtures had great effects on the morphology and sizes of aggregates, which were investigated by transmission electron microscopy and dynamic light scattering, respectively. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci., 2013
Frequency and temperature dependence of poly(N‐isopropylacrylamide) gel rheology
Authors: Parmar Avanish S. , Hill Shannon , Vidyasagar Ajay , Bello Carlos , Toomey Ryan , Muschol Martin 
Published: May 2012

AbstractPoly(N‐isopropylacrylamide) orp‐NIPAAM gels undergo a prominent deswelling transition near physiological temperatures. Using passive microrheology, we have investigated the viscoelastic response ofp‐NIPAAM gels over a frequency range not accessible to bulk rheological measurements. Overall, NIPAAM gels moderately shear stiffen with increasing frequency. More intriguingly, sample viscosity rapidly declines with increasing frequency before leveling off near the solvent viscosity. The frequency for this crossover coincides with the emergence of fast gel modes seen in dynamic light scattering (DLS) from the gel. Furthermore, we monitored viscoelastic responses on approach to the deswelling transition. Intrinsic light scattering indicates that experimental conditions are not near the critical point and that the deswelling transition is second order in nature. Nevertheless, the corresponding elastic and viscous moduli ofp‐NIPAAM displayed power‐law decreases with temperature. These changes with temperature were independent of probe frequency. Power law exponents, however, are sensitive to details of the sample preparation suggesting that these viscoelastic responses vary with gel structure. Correlating our microrheological measurements with DLS from the gel matrix itself, we find that several of the observed microrheological features are closely related to the intrinsic dynamics of thep‐NIPAAM gels. In particular, the transition from gel‐ to solvent dominated dissipation coincides with a transition from fast to slow gel modes. Combining microrheology with intrinsic light scattering, therefore, provides a compelling approach to probe rheological responses and correlate them to the underlying network dynamics. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci., 2013
Synthesis of a new siloxane‐containing alicyclic dianhydride and the derived polyimides with improved solubility and hydrophobicity
Authors: Xiong Lei , Wang Xiulong , Qi Haixia , Liu Feng 
Published: May 2012

AbstractThe structural transformation strategy of cis‐5‐norbornene‐endo‐2,3‐dicarboxylic anhydride (NA) was performed by esterification. The double bond on the diester of NA showed adequate hydrosilylation reactivity with SiH bonds of phenyl‐containing disiloxane. Thereby, a new siloxane‐containing alicyclic dianhydride, 5,5′‐exo‐(1,3‐dimethyl‐1,3‐diphenyl‐disiloxane‐1,5‐diyl)bisbicyclo[2,2,1]heptane‐2,3‐endo‐dicarboxylic anhydride 6 was successfully synthesized starting from NA, 1,3‐dimethyl‐1,3‐diphenyldisiloxane and platinum complex catalyst. The whole synthetic route of dianhydride 6 consisted of esterification, hydrosilylation, saponification, acidification, and dehydration. A series of polyimides (PIs) were prepared from dianhydride comonomers of 6 and 4,4′‐biphenyltetracarboxylic dianhydride (BPDA) in different molar ratio together with the diamine 4,4′‐oxydianiline (ODA). The thermal and mechanical properties of PIs showed somewhat decrease with increasing content of dianhydride 6. The solubility of PIs increased with the increasing content of dianhydride 6, and further calculation from Bragg's equation indicated that average interchain distance (d‐spacing value) increased with increasing content of siloxane and alicyclic segments in the backbone of PIs. It was revealed that the hydrophobicity of PIs increased with the increasing content of dianhydride 6. Polyimide 7g, which was prepared from 100% 6 and ODA, showed water adsorption of less than 0.7% and contact angle against water of 101.1°. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci., 2013
Reinforcement of pH‐responsive γ‐poly(glutamic acid)/chitosan hydrogel for orally administrable colon‐targeted drug delivery
Authors: Park Bo Gi , Kang Hahk‐Soo , Lee Wonbae , Kim Jung Suk , Son Tae‐Il 
Published: May 2012

AbstractOrally administrable hydrogel was prepared by crosslinking chitosan (CS) with γ‐poly(glutamic acid) (γ‐PGA) for an excellent pH‐responsive colon‐targeted drug delivery system. The stable crosslinked amide bond appeared in the shifted region of FTIR spectroscopy, and the tensile strength and elastic modulus were also reduced by crosslinking of CS and γ‐PGA. The surfaces of crosslinked hydrogel have a homogeneous pore array with pore size corresponding to the varied blending ratio. The swelling ratio was dramatically changed by increasing the pH from 3 to 6, and the responsiveness of swelling ratio to the reversible pH changes between 3 and 10 was reliable for 72 h. The drug diffusion rate was mainly dependent on the pH, and a water‐soluble tetrazolium (WST‐1) assay indicated that cytocompatibility of the hydrogel was in an acceptable range. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci. 2013