bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidence of active dinitrogen fixation in surface waters of the eastern tropical South Pacific during El Niño and La Niña events and evaluation of its potential nutrient controls
Authors: Dekaezemacker J. , Bonnet S. , Grosso O. , Moutin T. , Bressac M. , Capone D.G. 
Published: July 2013

AbstractBiological N2 fixation rates were quantified in the Eastern Tropical South Pacific (ETSP) during both El Niño (February 2010) and La Niña (March–April 2011) conditions, and from Low‐Nutrient, Low‐Chlorophyll (20°S) to High‐Nutrient, Low‐Chlorophyll (HNLC) (10°S) conditions. N2 fixation was detected at all stations with rates ranging from 0.01 to 0.88 nmol N L−1 d−1, with higher rates measured during El Niño conditions compared to La Niña. High N2 fixations rates were reported at northern stations (HNLC conditions) at the oxycline and in the oxygen minimum zone (OMZ), despite nitrate concentrations up to 30 µmol L−1, indicating that inputs of new N can occur in parallel with N loss processes in OMZs. Water‐column integrated N2 fixation rates ranged from 4 to 53 µmol N m−2 d−1 at northern stations, and from 0 to 148 µmol m−2 d−1 at southern stations, which are of the same order of magnitude as N2 fixation rates measured in the oligotrophic ocean. N2 fixation rates responded significantly to Fe and organic carbon additions in the surface HNLC waters, and surprisingly by concomitant Fe and N additions in surface waters at the edge of the subtropical gyre. Recent studies have highlighted the predominance of heterotrophic diazotrophs in this area, and we hypothesize that N2 fixation could be directly limited by inorganic nutrient availability, or indirectly through the stimulation of primary production and the subsequent excretion of dissolved organic matter and/or the formation of micro‐environments favorable for heterotrophic N2 fixation.
Long‐term care services expenditure projection in South Korea from 2015 to 2050
Authors: Kim Nayoung 
Published: July 2013

SummarySouth Korea has been undergoing significant change in its population structure over the past three decades. Within 10 years, South Korean baby‐boomers will reach the age of 65 years and accelerate this change. This trend in population structure is crucial, because an aging population may increase medical demand, especially that for long‐term care (LTC) services, which would create a financial burden on society.This study estimates total LTC expenditure in South Korea from 2015 to 2050 by modifying the method proposed by the UK Personal Social Science Research Unit, the seminal study on projecting costs of LTC services. Using population data from the projections of the Korean Statistical Information Service, I stratify the projected population by gender and age, using the groups 65–69, 70–74, 75–79 and 80 or over and divide LTC services into two categories, namely facility and home care.South Korea's total LTC expenditure is predicted to continuously increase and then reach 4.2% of GDP in 2050. Expenditure on LTC services for women is higher than that for men. Moreover, the increase in total expenditure is dramatic after 2040 for home‐based services but is constant for facility services. This study shows that the presence of baby‐boomers heavily influences LTC expenditure in South Korea. Copyright © 2013 John Wiley & Sons, Ltd.
Liberalising trade in health services: constraints and prospects for South Asian countries
Authors: Khatun Fahmida , Ahamad Mazbahul 
Published: July 2013

SummaryThis paper attempts to examine the prospects and challenges associated with liberalising trade in health services in five South Asian countries, namely Bangladesh, India, Nepal, Pakistan and Sri Lanka. Country‐specific secondary information, a brief literature review of empirical studies and debriefing sessions with key stakeholders are employed to explore the issues related to liberalising health services trade. The health sectors in India, Nepal and Pakistan are scheduled under General Agreement on Trade in Services (GATS) classification, whereas those in Bangladesh and Sri Lanka are not. In Bangladesh, there is opportunity for investment in joint venture hospitals under Mode 3. Nonetheless, India is the largest trader in health services under all four modes. In Sri Lanka, cross‐border trade in healthcare services is found to be insignificant. Moreover, expertise in eye treatment in Nepal could also attract foreign investment in medical services under Mode 3. In contrast, Pakistan exhibits no potential under Mode 4, because of a lack of healthcare professionals. In this view, the prospects of trade in health services within the South Asian region under the four GATS modes are constrained by infrastructural, regulatory, perception‐related, logistical and cultural problems. Considering the level of development and commercial opportunities, regional integration in the health sector could be explored in such areas as telemedicine, medical tourism, cross‐border investment and capacity building of health personnel. These developments call for stronger and pro‐active government‐to‐government collaboration in the South Asian Association of Regional Cooperation (SAARC) region in a transparent and accountable manner. Copyright © 2013 John Wiley & Sons, Ltd.
Incorporation of growth factor loaded microspheres into polymeric electrospun nanofibers for tissue engineering applications
Authors: Selcan Gungor‐Ozkerim P. , Balkan Timucin , Kose Gamze T. , Sezai Sarac A. , Kok Fatma N. 
Published: July 2013

AbstractNanofibrous double‐layer matrices were prepared by electrospinning technique with the bottom layer formed from PCL (poly‐ε‐caprolactone)/PLLA (poly‐l‐lactic acid) nanofibers and the upper layer from PCL/Gelatin nanofibers. Bottom layer was designed to give mechanical strength to the system, whereas upper layer containing gelatin was optimized to improve the cell adhesion. Gelatin microspheres were incorporated in the middle of two layers for controlled growth factor delivery. Successful fabrication of the blend nanofibers were shown by spectroscopy. Scanning electron microscopy results demonstrated that bead‐free nanofibers with uniform morphology could be obtained by 10% w/v concentrations of PCL/PLLA and PCL/Gelatin solutions. Microspheres prepared by 15% gelatin concentration and cross‐linked with 7.5% glutaraldehyde solution were chosen after in vitro release studies for the incorporation to the double‐layer matrices. The optimized conditions were used to prepare fibroblast growth factor‐2 (FGF‐2) loaded microspheres. Preliminary cell culture studies showed that the FGF‐2 could be actively loaded into the microspheres and enhanced the cell attachment and proliferation. The complete system had a slow degradation rate in saline (18% weight loss in 2 months) and it could meanwhile preserve its integrity. This sandwich system prevented microsphere leakage from the scaffold, and the hydrophilic and bioactive nature of the fibers at the upper layer promoted cell attachment to the surface. PLLA/PCL layer, on the other hand, improved the mechanical properties of the system and enabled better handling. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 1897–1908, 2014.
Elastic properties of human posterior eye
Authors: Chen Kinon , Rowley Adrian P. , Weiland James D. , Humayun Mark S. 
Published: July 2013

AbstractThis study examines the elastic properties of the human posterior retina, choroid, and sclera. Twenty‐four human eyes from 30‐ to 74‐year‐old donors were obtained from an eye bank. Vertically and horizontally oriented tissue strips of the retina, choroid, and sclera (ideally n = 12 in each group) were harvested from the posterior eyes. Their thicknesses were estimated optically. The samples were stretched at 1 mm/s in 37°C saline. Stress and strain were obtained from the mechanical tests, and then the transition stress, transition strain, toe modulus, and heel modulus were calculated. Statistical analysis was performed for comparison between groups. Linear regression analyses were used to explore the relationship between the mechanical parameters and age. We found that the stress–strain relationship of the retina, choroid, and sclera were nonlinear. Except for the retinal transition strain (p = 0.0124), no statistical difference was found between the vertical and horizontal meridian in the mechanical parameters (p > 0.05). Furthermore, weak relationship was observed between some of the mechanical parameters and the donors' age. Our results suggest that there is significant anisotropy in the retina, and mechanical properties of each layer may change with age. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2001–2007, 2014.
Cell‐penetrating peptides: Achievements and challenges in application for cancer treatment
Authors: Shin Meong Cheol , Zhang Jian , Min Kyoung Ah , Lee Kyuri , Byun Youngro , David Allan E. , He Huining , Yang Victor C. 
Published: July 2013

AbstractOne of the major hurdles to cure cancer lies in the low potency of currently available drugs, which could eventually be solved by using more potent therapeutic macromolecules, such as proteins or genes. However, although these macromolecules possess greater potency inside the cancer cells, the barely permeable cell membrane remains a formidable barrier to exert their efficacy. A widely used strategy is to use cell penetrating peptides (CPPs) to improve their intracellular uptake. Since the discovery of the first CPP, numerous CPPs have been derived from natural or synthesized products. Both in vitro and in vivo studies have demonstrated that those CPPs are highly efficient in transducing cargoes into almost all cell types. Therefore, to date, CPPs have been widely used for intracellular delivery of various cargoes, including peptides, proteins, genes, and even nanoparticles. In addition, recently, based on the successes of CPPs in cellular studies, their applications in vivo have been actively pursued. This review will focus on the advanced applications of CPP‐based in vivo delivery of therapeutics (e.g., small molecule drugs, proteins, and genes). In addition, we will highlight certain updated applications of CPPs for intracellular delivery of nanoparticulate drug carriers, as well as several “smart” strategies for tumor targeted delivery of CPP‐cargoes. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 575–587, 2014.
MC3T3‐E1 and RAW264.7 cell response to hydroxyapatite and alpha‐type alumina adsorbed with bovine serum albumin
Authors: Kawashita Masakazu , Hayashi Jumpei , Kudo Tada‐aki , Kanetaka Hiroyasu , Li Zhixia , Miyazaki Toshiki , Hashimoto Masami 
Published: July 2013

AbstractInitial cell responses following implantation are important for inducing osteoconductivity. We investigated cell adhesion, spreading, and proliferation in response to native and bovine serum albumin (BSA)‐adsorbed disc of hydroxyapatite (HA) or alpha‐type alumina (α‐Al2O3) using mouse MC3T3‐E1 osteoblastic cells and mouse RAW264.7 macrophages. The adsorbed BSA inhibited adhesion and spreading of MC3T3‐E1 cells, but did not affect MC3T3‐E1 cell proliferation on HA and α‐Al2O3 substrates. Thus, MC3T3‐E1 cells quickly adhere to original HA before cell binding is impeded by adsorption of BSA in quantities sufficient to inhibit the adhesion of MC3T3‐E1 cells. The adsorbed BSA inhibits adhesion of RAW264.7 cells to α‐Al2O3, but not to HA. BSA adsorption does not affect RAW264.7 cell spreading and proliferation on both HA and α‐Al2O3 substrates. Thus, BSA adsorbed on HA stimulates a different cell response than α‐Al2O3. Moreover, quick adherence of osteoblast cells and monocyte‐macrophage lineage cells plays a role in HA osteoconductivity. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 1880–1886, 2014.
Considerations in binding diblock copolymers on hydrophilic alginate beads for providing an immunoprotective membrane
Authors: Spasojevic Milica , Bhujbal Swapnil , Paredes Genaro , de Haan Bart J. , Schouten Arend J. , de Vos Paul 
Published: July 2013

AbstractAlginate‐based microcapsules are being proposed for treatment of many types of diseases. A major obstacle however in the successes is that these capsules are having large lab‐to‐lab variations. To make the process more reproducible, we propose to cover the surface of alginate capsules with diblock polymers that can form polymer brushes. In the present study, we describe the stepwise considerations for successful application of diblock copolymer of polyethylene glycol (PEG) and poly‐L‐lysine (PLL) on the surface of alginate beads. Special procedures had to be designed as alginate beads are hydrophilic and most protocols are designed for hydrophobic biomaterials. The successful attachment of diblock copolymer and the presence of PEG blocks on the surface of the capsules were studied by fluorescence microscopy. Longer time periods, that is, 30–60 min, are required to achieve saturation of the surface. The block lengths influenced the strength of the capsules. Shorter PLL blocks resulted in less stable capsules. Adequate permeability of the capsules was achieved with poly(ethylene glycol)‐block‐poly(L‐lysine hydrochloride) (PEG454‐b‐PLL100) diblock copolymers. The capsules were a barrier for immunoglobulin G. The PEG454‐b‐PLL100 capsules have similar mechanical properties as PLL capsules. Minor immune activation of nuclear factor κB in THP‐1 monocytes was observed with both PLL and PEG454‐b‐PLL100 capsules prepared from purified alginate. Our results show that we can successfully apply block copolymers on the surface of hydrophilic alginate beads without interfering with the physicochemical properties. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 1887–1896, 2014.
Microstructural effects on the wear behavior of a biomedical as‐cast Co‐27Cr‐5Mo‐0.25C alloy exposed to pulsed laser melting
Authors: Acevedo‐Dávila J. L. , López H. F. , Cepeda‐Rodríguez F. , Rodriguez‐Reyes M. , García‐Vazquez F. , Hernández‐Garcia H. M. 
Published: July 2013

AbstractIn this work, the effect of pulsed laser melting on the exhibited microstructure and properties of a cast Co‐27Cr‐5Mo‐0.25C alloy was investigated. In particular, properties such as surface hardness and wear behavior of the laser modified microstructure were determined as a function of the implemented laser melting parameters. It was found that laser melting promotes significant grain refinement while preventing the precipitation of coarse carbide phases. Apparently, a refined dendritic grain structure develops which is surrounded by a fine carbide distribution in the interdendritic regions. Moreover, the high‐temperature face centered cubic (FCC) phase remains untransformed at room temperature. Hardness measurements and wear testing using a Pin‐On‐Disk tribological machine indicate that the modified laser surfaces exhibit both, high wear resistance and high microhardness when compared with the untreated as‐cast Co‐27Cr‐5Mo‐0.25C alloy. In particular, it was found that the laser modified surfaces exhibit improved wear and friction properties comparable to the ones found in Co‐Cr‐Mo alloys with a predominantly hexagonal closest packed (HCP) matrix. However, surface defects associated with the laser process can be detrimental for the improved wear performance and they should be considered in identifying the proper laser parameters in alloy melting. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2008–2016, 2014.
The structurally effect of surface coated rhamnogalacturonan I on response of the osteoblast‐like cell line SaOS‐2
Authors: Svava Rikke , Gurzawska Katarzyna , Yihau Yu , Haugshøj Kenneth Brian , Dirscherl Kai , Levery Steven B. , Jørgensen Niklas Rye , Gotfredsen Klaus , Damager Iben , Ulvskov Peter , Jørgensen Bodil 
Published: July 2013

AbstractOsseointegration is important when implants are inserted into the bone and can be improved by biochemical surface coating of the implant. In this paper enzymatically modified rhamnogalacturonan I (RG‐I) from apple and lupin was used for biochemical coating of aminated surfaces and the importance of the quality of RG‐I, the nature of the binding, the fine structure of RG‐I, and its effect on SaOS‐2 cell line cultured on coated surfaces was investigated. SaOS‐2 cells are osteoblast‐like cells and a well‐established in vitro model of bone‐matrix forming osteoblasts. Purification by gel filtration could remove small fragments of galacturonic acid (GalA) and binding studies showed that the purity of the RG‐I molecules was important for the quality of the coating. The structure of RG‐I and osteoblast‐like cells' viability were positively correlated so that high content of 1,4‐linked galactose (Gal) and a low content of arabinose in the RG‐I molecules favored cell viability. These results indicate that coating of implants with RG‐I affect osseointegration positively. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 1961–1971, 2014.
A review of integrating electroactive polymers as responsive systems for specialized drug delivery applications
Authors: Pillay Viness , Tsai Tong‐Sheng , Choonara Yahya E. , du Toit Lisa C. , Kumar Pradeep , Modi Girish , Naidoo Dinesh , Tomar Lomas K. , Tyagi Charu , Ndesendo Valence M. K. 
Published: July 2013

AbstractElectroactive polymers (EAPs) are promising candidate materials for the design of drug delivery technologies, especially in conditions where an “on–off” drug release mechanism is required. To achieve this, EAPs such as polyaniline, polypyrrole, polythiophene, ethylene vinyl acetate, and polyethylene may be blended into responsive hydrogels in conjunction with the desired drug to obtain a patient‐controlled drug release system. The “on–off” drug release mechanism can be achieved through the environmental‐responsive nature of the interpenetrating hydrogel‐EAP complex via (i) charged ions initiated diffusion of drug molecules; (ii) conformational changes that occur during redox switching of EAPs; or (iii) electroerosion. These release mechanisms are not exhaustive and new release mechanisms are still under investigation. Therefore, this review seeks to provide a concise incursion and critical overview of EAPs and responsive hydrogels as a strategy for advanced drug delivery, for example, controlled release of neurotransmitters, sulfosalicyclic acid from cross‐linked hydrogel, and vaccine delivery. The review further discusses techniques such as linear sweep voltammetry, cyclic voltammetry, impedance spectroscopy, and chronoamperometry for the determination of the redox capability of EAPs. The future implications of the hydrogel‐EAP composites include, but not limited to, application toward biosensors, DNA hybridizations, microsurgical tools, and miniature bioreactors and may be utilized to their full potential in the form of injectable devices as nanorobots or nanobiosensors. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2039–2054, 2014.
Photoinitiated chemical vapor deposition of cytocompatible poly(2‐hydroxyethyl methacrylate) films
Authors: McMahon Brian J. , Pfluger Courtney A. , Sun Bing , Ziemer Katherine S. , Burkey Daniel D. , Carrier Rebecca L. 
Published: July 2013

AbstractPoly(2‐hydroxyethyl methacrylate) (pHEMA) is a widely utilized biomaterial due to lack of toxicity and suitable mechanical properties; conformal thin pHEMA films produced via chemical vapor deposition (CVD) would thus have broad biomedical applications. Thin films of pHEMA were deposited using photoinitiated CVD (piCVD). Incorporation of ethylene glycol diacrylate (EGDA) into the pHEMA polymer film as a crosslinker, confirmed via Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy, resulted in varied swelling and degradation behavior. 2‐Hydroxyethyl methacrylate‐only films showed significant thickness loss (up to 40%), possibly due to extraction of low‐molecular‐weight species or erosion, after 24 h in aqueous solution, whereas films crosslinked with EGDA (9.25–12.4%) were stable for up to 21 days. These results differ significantly from those obtained with plasma‐polymerized pHEMA, which degraded steadily over a 21‐day period, even with crosslinking. This suggests that the piCVD films differ structurally from those fabricated via plasma polymerization (plasma‐enhanced CVD). piCVD pHEMA coatings proved to be good cell culture materials, with Caco‐2 cell attachment and viability comparable to results obtained on tissue‐culture polystyrene. Thus, thin film CVD pHEMA offers the advantage of enabling conformal coating of a cell culture substrate with tunable properties depending on method of preparation and incorporation of crosslinking agents. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2375–2382, 2014.
Development and assessment of a biodegradable solvent cast polyester fabric small‐diameter vascular graft
Authors: Melchiorri Anthony J. , Hibino Narutoshi , Brandes Zachary R. , Jonas Richard A. , Fisher John P. 
Published: July 2013

AbstractAdjusting the mechanical properties of polyester‐based vascular grafts is crucial to achieving long‐term success in vivo. Although previous studies using a fabric‐based approach have achieved some success, a central issue with pure poly(lactic acid) (PLA) or poly(glycolic acid) (PGA) grafts sealed with poly(dl‐caprolactone‐co‐lactic acid) (P(CL/LA)) has been stenosis. Intimal hyperplasia, a leading cause of stenosis, can be caused by the mechanical incompatibility of synthetic vascular grafts. Investigating the performance of poly(glycolic‐co‐lactic acid) (PGLA) grafts could lead to insight into whether graft stenosis stems from mechanical issues such as noncompliance and unfavorable degradation times. This could be achieved by examining grafts with tunable mechanical properties between the ranges of such properties in pure PGA and PLA‐based grafts. In this study, we examined PGLA‐based grafts sealed with different P(CL/LA) solutions to determine the PGLA‐P(CL/LA) grafts' mechanical properties and tissue functionality. Cell attachment and proliferation on graft surfaces were also observed. For in vivo assessment, grafts were implanted in a mouse model. Mechanical properties and degradation times appeared adequate compared to recorded values of vessels used in autograft procedures. Initial neotissue formation was observed in the grafts and patency maintained during the pilot study. This study presents a ∼1‐mm diameter degradable graft demonstrating suitable mechanical properties and in vivo pilot study success, enabling further investigation into the tuning of mechanical properties to reduce complications in degradable polyester fabric‐based vascular grafts. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 1972–1981, 2014.
Quantitative biocompatibility evaluation of nickel‐free high‐nitrogen stainless steel in vitro/in vivo
Authors: Inoue Motoki , Sasaki Makoto , Katada Yasuyuki , Taguchi Tetsushi 
Published: July 2013

AbstractCoronary stents must not provoke an inflammatory response; however, some kinds of ions that are released from biometals induce biological reaction. In the present study, we quantitatively evaluated biological reaction of nickel‐free high‐nitrogen stainless steel (HNS) by endothelial cell culture, and a bioimaging system using NF‐κB/luciferase transgenic mice to confirm the potential of HNS for the application of coronary stent. Endothelialization was greater with HNS than with commercial stainless steel (SUS316L). In vivo inflammatory response of HNS was lower than that of SUS316L. These differences may be related to the amounts of nickel ion eluted from the stents, as HNS did not elute nickel ion. These data suggest that HNS may be useful as a material for coronary artery stents. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 68–72, 2014.