bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface vegetation patterning controls carbon accumulation in peatlands
Authors: Loisel Julie , Yu Zicheng 
Published: July 2013

AbstractLocalized ecohydrological feedbacks have been proposed as important internal drivers of patterns and processes in terrestrial ecosystems. However, there is a significant gap between the prominence of theoretical models and the paucity of observations describing linkages between ecosystem structure and functioning. Here we report empirical evidence for strong interactions between surface vegetation patterning and long‐term carbon sequestration rates in four peat bogs in Patagonia on the basis of high‐resolution stratigraphic analyses. Peatland development across the study region was characterized by repeated switches between wet‐ and dry‐adapted plant communities, depicting changes between hollows (wet assemblages) and lawns (dry assemblages) that could represent past surface patterning. We found a site‐specific relationship between the frequency of the wet‐to‐dry cycles and carbon accumulation rates that followed a power function, with rapid vegetation shifts causing high peat accumulation rates. Our results show strong evidence for internal regulation of vegetation dynamics and peatland growth, implying that understanding peatland processes is a prerequisite for peat‐based paleoclimate reconstructions.
Cassini CAPS‐ELS observations of negative ions in Titan's ionosphere: Trends of density with altitude
Authors: Wellbrock A. , Coates A. J. , Jones G. H. , Lewis G. R. , Waite J. H. 
Published: July 2013

AbstractObservations with the Electron Spectrometer sensor of the Cassini Plasma Spectrometer (CAPS‐ELS) have revealed the existence of negative ions in Titan's ionosphere. Negative ions are observed during encounters whenever the instrument points in the ram direction at altitudes 950–1400 km. Complex hydrocarbon and nitrile chemical processes are believed to take place which play a role in haze formation. The heaviest ions observed so far have masses up to 13,800 amu/q. Using data from 34 Titan encounters, we show for the first time negative ion density trends of different mass groups, including total densities, with altitude. We determine peak densities and the associated altitudes at which they are observed and the highest altitudes at which individual mass groups are found.
An explanation of bright areas inside Shackleton Crater at the Lunar South Pole other than water‐ice deposits
Authors: Haruyama Junichi , Yamamoto Satoru , Yokota Yasuhiro , Ohtake Makiko , Matsunaga Tsuneo 
Published: July 2013

AbstractWhether water molecules of cometary and/or solar wind origin migrated to and accumulated in cold permanently shadowed areas at the lunar poles has long been debated from the perspective of scientific interest and expectations for future utilization. Recently, high reflectance condition was observed inside the lunar South Pole Shackleton Crater for the 1064.4 nm of the Lunar Orbiter Laser Altimeter on the Lunar Reconnaissance Orbiter, and the high reflectance was explained to perhaps be due to a surface frost layer in excess of 20% water‐ice. Here we investigate the crater with the Selenological Engineering Explorer Multi‐band imager that has nine bands in the visible to near‐infrared range, including a 1050 nm band (62 m/pixel resolution). Part of the illuminated inner wall of Shackleton Crater exhibits high reflectance at 1050 nm but also exhibits the diagnostic 1250 nm spectral absorption, a signature that is consistent with naturally bright purest anorthosite.
Hydrogeochemical interpretation of water seepage through a geological barrier at a reservoir boundary
Authors: Kim Gyoo‐Bum , Park Joon‐Hyeong 
Published: July 2013

AbstractA geological barrier such as a mountain ridge surrounding a large reservoir generally plays some part in preventing water leakage from the reservoir, but water flows out naturally according to the hydraulic gradient because the reservoir water level is typically higher than that outside. The hydrogeological, geochemical, and isotopic properties of water in the Daechung Dam area were analysed to characterize the source and the phenomenon of the groundwater flowing through the geological barrier. Our geochemical analysis showed that the concentrations of anions and cations tended to increase, due to the longer residence time of the water, as the distance between the sampling site and reservoir increased. Elevation differences (calculated using oxygen and hydrogen isotopes) between the highest and lowest sampling sites ranged between 350 and 420 m based on the altitude effect on isotope concentration, but the actual difference was only 35 m. These results, including analysis of the rate of water seepage from the reservoir (ca. 2.3% to 14.4% of natural recharge), indicate the possibility that groundwater in the study area originated from reservoir water that was derived from upstream water and rainfall in the high mountainous area of the upper watershed. Copyright © 2013 John Wiley & Sons, Ltd.
Interpretation of mean‐field bias correction of radar rain rate using the concept of linear regression
Authors: Yoo Chulsang , Park Cheolsoon , Yoon Jungsoo , Kim Jungho 
Published: July 2013

AbstractIn this study, the correction problem of mean‐field bias of radar rain rate was investigated using the concept of linear regression. Three different relationships were reviewed for their slopes to be used as the bias correction factor: Relationship 1 (R1) is based on the conventional linear regression, relationship 2 (R2) is forced to pass the origin and relationship 3 (R3) is the line whose slope is the G/R ratio. In other words, R1 is the regression line connecting the intercept and the mass centre of measurement pairs, R2 is the regression line forced to pass the origin, and R3 is the line connecting the origin and the mass centre. The slopes of all three relationships were reviewed analytically to compare them, and thereby, the effect of zero measurements could be evaluated. Additionally, the effect of using switched independent and dependent variables on the derived slopes was also evaluated. The theoretically derived results were then verified by analysing the rainfall event on 10–11 August 2010 in Korea. Finally, the difference between the bias‐corrected radar rain rate and the rain gauge rain rate was quantified by root mean square error and mean error so that it could be used as a measure for the evaluation of bias correction factors. In conclusion, the slope of R2 was found to be the best for the bias correction factor. However, when deciding the slope of this R2, the radar rain rate should be used as the independent variable in the low rain rate region, and the rain gauge rain rate in the high rain rate region above a certain threshold. Copyright © 2013 John Wiley & Sons, Ltd.
Dose‐dependent surface endothelialization and biocompatibility of polyurethane noble metal nanocomposites
Authors: Hess Christian , Schwenke Andreas , Wagener Philipp , Franzka Steffen , Laszlo Sajti Csaba , Pflaum Michael , Wiegmann Bettina , Haverich Axel , Barcikowski Stephan 
Published: July 2013

AbstractSurface pre‐endothelialization is a promising approach to improve the hemocompatibility of implants, medical devices, and artificial organs. To promote the adhesive property of thermoplastic polyurethane (TPU) for endothelial cells (ECs), up to 1 wt % of gold (Au) or platinum (Pt) nanoparticles, fabricated by pulsed laser ablation in polymer solution, were embedded into the polymer matrix. The analysis of these nanocomposites showed a homogenous dispersion of the nanoparticles, with average diameters of 7 nm for Au or 9 nm for Pt. A dose‐dependent effect was found when ECs were seeded onto nanocomposites comprising different nanoparticle concentrations, resulting in a fivefold improvement of proliferation at 0.1 wt % nanoparticle load. This effect was associated with a nanoparticle concentration‐dependent hydrophilicity and negative charge of the nanocomposite. In dynamic flow tests, nanocomposites containing 0.1 wt % Au or Pt nanoparticles allowed for the generation of a confluent and resistant EC layer. Real‐time polymerase chain reaction quantification of specific markers for EC activation indicated that ECs cultivated on nanocomposites remain in an inactivated, nonthrombogenic and noninflammatory state; however, maintain the ability to trigger an inflammatory response upon stimulation. These findings were confirmed by a platelet and leukocyte adhesion assay. The results of this study suggest the possible applicability of TPU nanocomposites, containing 0.1 wt % Au or Pt nanoparticles, for the generation of pre‐endothelialized surfaces of medical devices. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 1909–1920, 2014.
Increased osseointegration effect of bone morphogenetic protein 2 on dental implants: An in vivo study
Authors: Yoo Daniel , Tovar Nick , Jimbo Ryo , Marin Charles , Anchieta Rodolfo B. , Machado Lucas S. , Montclare Jin , Guastaldi Fernando P. S. , Janal Malvin N. , Coelho Paulo G. 
Published: July 2013

AbstractApplication of recombinant human bone morphogenetic protein 2 (rhBMP‐2) to implant surfaces has been of great interest due to its osteoinductive potential. However, the optimal coating methodology has not been clarified. The objective of the study was to determine whether the application of rhBMP‐2 onto plasma‐sprayed hydroxyapatite implant surfaces by immersion in protein solution before implant installation would result in significantly improved bone apposition. Using a sheep iliac model, titanium (Ti) and plasma‐sprayed calcium–phosphate (PSCaP)‐coated implants uncoated and coated with rhBMP‐2 were assessed for their osteogenic effects in the peri‐implant area over time in terms of osseointegration and de novo bone formation. After 3 and 6 weeks postoperatively, the samples were retrieved and were subjected to bone‐to‐implant contact (BIC) and bone area fraction occupancy (BAFO) evaluation. When rhBMP‐2 was applied to the PSCaP surface, significant increases in BIC and BAFO were observed at 3 weeks in vivo, whereas when adsorbed directly onto the titanium implant surface, rhBMP‐2 did not as effectively improve the bone response (although significantly higher than control Ti). The outcomes of the present study suggested that the combination of plasma‐sprayed calcium–phosphate surface and rhBMP‐2 coating significantly enhanced osseointegration, which validated the postulated hypothesis. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 1921–1927, 2014.
Sericin–carboxymethyl cellulose porous matrices as cellular wound dressing material
Authors: Nayak Sunita , Kundu S. C. 
Published: July 2013

AbstractIn this study, porous three‐dimensional (3D) hydrogel matrices are fabricated composed of silk cocoon protein sericin of non‐mulberry silkworm Antheraea mylitta and carboxymethyl cellulose. The matrices are prepared via freeze‐drying technique followed by dual cross‐linking with glutaraldehyde and aluminum chloride. The microstructure of the hydrogel matrices is assessed using scanning electron microscopy and biophysical characterization are carried out using Fourier transform infrared spectroscopy and X‐ray diffraction. The transforming growth factor β1 release from the cross‐linked matrices as a growth factor is evaluated by immunosorbent assay. Live dead assay and 3‐[4,5‐dimethylthiazolyl‐2]‐2,5‐diphenyl tetrazolium bromide assay show no cytotoxicity of blended matrices toward human keratinocytes. The matrices support the cell attachment and proliferation of human keratinocytes as observed through scanning electron microscope and confocal images. Gelatin zymography demonstrates the low levels of matrix metalloproteinase 2 (MMP‐2) and insignificant amount of MMP‐9 in the culture media of cell seeded matrices. Low inflammatory response of the matrices is indicated through tumor necrosis factor alpha release assay. The results indicate that the fabricated matrices constitute 3D cell‐interactive environment for tissue engineering applications and its potential use as a future cellular biological wound dressing material. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Synthesis, characterization, and antiplasmodial activity of polymer‐incorporated aminoquinolines
Authors: Aderibigbe B. A. , Neuse E. W. , Sadiku E. R. , Shina Ray S. , Smith P. J. 
Published: July 2013

AbstractIn this research, aminoquinoline compounds were synthesized, characterized, and incorporated into water‐soluble polymers to form conjugates. The conjugates were characterized by X‐ray diffraction, thermal gravimetric analysis, scanning electron microscope, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy to confirm the successful incorporation of the aminoquinoline compound on to the polymer. The synthesized conjugates were screened for in vitro antiplasmodial activity in triplet test against chloroquine‐sensitive strain of Plasmodium falciparum and chloroquine drug was used as a reference drug in all the experiments. A full dose–response was performed to determine the concentration inhibiting 50% of parasite growth (IC50 value). Polymeric conjugates containing 3‐diethylamino‐1‐propylamine solubilizing units were found to be most active against the chloroquine‐sensitive strain of P. falciparum. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 1941–1949, 2014.
A novel coculture model of HUVECs and HUASMCs by hyaluronic acid micropattern on titanium surface
Authors: Li Jingan , Zhang Kun , Xu Ying , Chen Jiang , Yang Ping , Zhao Yuancong , Zhao Ansha , Huang Nan 
Published: July 2013

AbstractOrientation smooth muscle cell environment plays a positive role in the development of a functional, adherent endothelium. Therefore, building an orientation coculture model of endothelial cells (ECs) and smooth muscle cells (SMCs) on biomaterials surface may provide more help for understanding the interaction between the two cells in vitro. In the present study, a “SMCs‐ColIV‐ECs” coculture model was built on the hyaluronic acid (HA) patterned titanium (Ti) surface, and compared with the previous “SMCs‐HAa‐ECs” model on endothelial cell number, morphology index, nitric oxide (NO), and prostacyclin2 (PGI2) release, anticoagulation property, human umbilical artery smooth muscle cells (HUASMCs) inhibition property and retention under fluid flow shear stress. The result indicated that “SMCs‐ColIV‐ECs” model could enhance the number, spreading area, and major/minor index of human umbilical vein endothelial cells (HUVECs), which contributed to the retention of HUVECs on the surface. Greater major/minor index may produce more NO and PGI2 release, contributing to the anticoagulation property and HUASMCs inhibition property. In summary, this novel “SMCs‐ColIV‐ECs” coculture model improved the previous “SMCs‐HAa‐ECs” model, and may provide more inspiration for the human vascular intima building on the biomaterials in vitro. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 1950–1960, 2014.
Graphene oxide nanoparticles for enhanced photothermal cancer cell therapy under the irradiation of a femtosecond laser beam
Authors: Li Jing‐Liang , Hou Xue‐Liang , Bao Hong‐Chun , Sun Lu , Tang Bin , Wang Jin‐Feng , Wang Xun‐Gai , Gu Min 
Published: July 2013

AbstractNano‐sized graphene and graphene oxide (GO) are promising for biomedical applications, such as drug delivery and photothermal therapy of cancer. It is observed in this work that the ultrafast reduction of GO nanoparticles (GONs) with a femtosecond laser beam creates extensive microbubbling. To understand the surface chemistry of GONs on the microbubble formation, the GONs were reduced to remove most of the oxygen‐containing groups to get reduced GONs (rGONs). Microbubbling was not observed when the rGONs were irradiated by the laser. The instant collapse of the microbubbles may produce microcavitation effect that brings about localized mechanical damage. To understand the potential applications of this phenomenon, cancer cells labeled with GONs or rGONs were irradiated with the laser. Interestingly, the microbubbling effect greatly facilitated the destruction of cancer cells. When microbubbles were produced, the effective laser power was reduced to less than half of what is needed when microbubbling is absent. This finding will contribute to the safe application of femtosecond laser in the medical area by taking advantage of the ultrafast reduction of GONs. It may also find other important applications that need highly localized microcavitation effects. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2181–2188, 2014.
Immunocompatibility evaluation of hydrogel‐coated polyimide implants for applications in regenerative medicine
Authors: Sirova Milada , Vlierberghe Sandra Van , Matyasova Veronika , Rossmann Pavel , Schacht Etienne , Dubruel Peter , Rihova Blanka 
Published: July 2013

AbstractImmunocompatibility of gelatin‐based hydrogels to be applied as implant coatings for local regenerative treatment has been studied. First, the bio‐ and immuno‐acceptability of the methacrylamide‐modified gelatin hydrogels per se was screened. The results indicated that the hydrogels support cell growth. Metabolic activity of normal cells and permanent cell lines representing various cell types (endothelial, epithelial, fibroblast, and monocyte/macrophage) cultivated on the gelatin hydrogels was moderately lower compared to cells cultivated on tissue culture plastic. The cells cultivated on the hydrogels produced identical cytokines as the control cells although at lower levels. Importantly, no inflammatory activity, measured by nitric oxide and pro‐inflammatory cytokine (IL‐1α, IL‐6, and TNFα) production, was observed in peritoneal cells and monocyte/macrophage RAW 264.7 cell line cultivated on the hydrogels. Finally, polyimide (PI) implantable membranes were surface‐modified with gelatin hydrogels and screened for their in vivo immunocompatibility. Their histological examination performed after subcutaneous implantation in mice produced a sound proof of immunoacceptability. Normal tissue repair, mild cellular infiltration and edema mainly induced by the surgery were observed after 2 and 6 days. No adverse tissue responses were induced by the implants. Analysis performed after 4 and 9 weeks indicated areas of foreign body granuloma without formation of a fibrous capsule. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 1982–1990, 2014.
A comparison of the stress corrosion cracking susceptibility of commercially pure titanium grade 4 in Ringer's solution and in distilled water: A fracture mechanics approach
Authors: Roach Michael D. , Williamson R. Scott , Thomas Joseph A. , Griggs Jason A. , Zardiackas Lyle D. 
Published: July 2013

AbstractFrom the results of laboratory investigations reported in the literature, it has been suggested that stress corrosion cracking (SCC) mechanisms may contribute to early failures in titanium alloys that have elevated oxygen concentrations. However, the susceptibility of titanium alloys to SCC in physiological environments remains unclear. In this study, a fracture mechanics approach was used to examine the SCC susceptibility of CP titanium grade 4 in Ringer's solution and distilled de‐ionized (DI) water, at 37°C. The study duration was 26 weeks, simulating the non‐union declaration of a plated fracture. Four wedge loads were used corresponding to 86–95% of the alloy's ligament yield load. The longest cracks were measured to be 0.18 mm and 0.10 mm in Ringer's solution and DI water, respectively. SEM analysis revealed no evidence of extensive fluting and quasi‐cleavage fracture features which, in literature reports, were attributed to SCC. We thus postulate that the Ringer's solution accelerated the wedge‐loaded crack growth without producing the critical stresses needed to change the fracture mechanism. Regression analysis of the crack length results led to a significant best‐fit relationship between crack growth velocity (independent variable) and test electrolyte, initial wedge load, and time of immersion of specimen in electrolyte (dependent variables). © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 73–79, 2014.
Osteoconductivity and biodegradation of synthetic bone substitutes with different tricalcium phosphate contents in rabbits
Authors: Yang Cheryl , Unursaikhan Otgonbayar , Lee Jung‐Seok , Jung Ui‐Won , Kim Chang‐Sung , Choi Seong‐Ho 
Published: July 2013

AbstractVarious synthetic bone substitutes have been developed to reconstruct the bony defects that clinicians often encounter during surgical procedures. Among various synthetic bone substitutes, calcium phosphate (Ca‐P) ceramics have been investigated because their composition and structure are similar to those of human bone. We evaluated the bone healing and biodegradation patterns of three types of Ca‐P ceramic particle with various hydroxyapatite (HA)/β‐tricalcium phosphate (β‐TCP) weight ratio: pure β‐TCP, biphasic Ca‐P (BCP) with a HA/β‐TCP weight ratio of 60/40 (BCP 60/40), and BCP with an HA/β‐TCP weight ratio of 20/80 (BCP 20/80). Four 8‐mm‐diameter defects were created in ten rabbits. Three of the defects in each rabbit were separately and randomly filled with one of the three experimental Ca‐P ceramic particles, and the fourth was filled with blood clots (control). The specimens were harvested at 2 and 8 weeks post‐surgery. The histologic and histometric findings revealed that the augmented space and new bone formation were significantly better for all three Ca‐P ceramics than for the control group at both 2 and 8 weeks (p< 0.05). Compared to the pure β‐TCP, the two BCP groups were found to provide a larger amount of newly formed bone and bone density at the 2‐ and 8‐week post‐operative periods (p< 0.05). Throughout the observation period, BCP 60/40 and BCP 20/80 exhibited a similar bone healing and biodegradation patterns with regard to both individual particles and the total augmented areain vivo. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 80–88, 2014.
On the potential of hydrated storage for naturally derived ECMs and associated effects on mechanical and cellular performance
Authors: Davis L. M. , Callanan A. , Carroll G. T. , Doyle B. J. , Walsh M. T. , McGloughlin T. M. 
Published: July 2013

AbstractTissue engineered acellular vascular grafts are an emerging concept in the development of vascular prostheses for the minimally invasive treatment of cardiovascular diseases. Extracellular matrix (ECM) scaffolds, such as small intestinal submucosa (SIS) and urinary bladder matrix (UBM), offer many advantages over currently available synthetic devices. However, storage of such biomaterials can unduly influence the scaffold properties. This study evaluated the effects of up to 16 weeks hydrated storage on the mechanical and cellular performance of stented and unstented tubular scaffolds. This study aimed to demonstrate the viability, mechanical integrity, and bioactive potential of xenogeneic ECMs as potential off‐the‐shelf vascular prosthetic devices. Rehydrated ECM samples versus the lyophilized controls showed an increase in UTS and stiffness. The mechanical strength of all samples evaluated was above the average reported aortic tissue failure strength and more compliant than current synthetic materials employed. Post‐storage cellular bioactivity investigations indicated that both ECM scaffolds tested were unaffected by increased hydrated storage duration when compared with the controls. Overall, the results indicate that the biomechanical and biologic properties of ECMs are not negatively affected by long‐term hydrated storage. Therefore, with further investigations, naturally derived ECM materials may offer potential as an off‐the‐shelf therapeutic treatment of cardiovascular diseases. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 89–97, 2014.