bluuebunny/crossref_metadata_2025_split huggingface dataset:
A recharge model for high altitude, arid, Andean aquifers
Authors: Houston John 
Published: May 2009

AbstractEvidence for groundwater recharge in arid zones is mounting, despite early ideas that recharge was unlikely where evaporation greatly exceeded precipitation. The mechanisms and magnitude of groundwater recharge in the Andes and Atacama Desert are not well known but the subject of current research. Diffuse recharge is expected to be limited to high altitude areas with coarse‐grained soils devoid of vegetation. A recharge model for this environment is developed based on a simple soil moisture budgeting technique and the calculation of actual evaporation based on empirical studies. The model is run with data for the Linzor basins, over 4000 m elevation at 22·2°S on the west slope of the Andes. It is checked against independent estimates based on the chloride mass balance (CMB) method and flood events measured downstream in the Río Salado and found to provide robust and reliable results. The results indicate that irregular and volumetrically limited amounts of diffuse recharge occur at high elevations in half of all years, with a tendency to cluster during La Niña episodes. For the Linzor Basins, mean annual recharge is found to be equivalent to 28 mm a−1, although no recharge occurs in years with precipitation less than 120 mm, and increases proportionately with annual rainfall amounts above this limit. Copyright © 2009 John Wiley & Sons, Ltd.
Producing stylized videos using the AnimVideo rendering tool
Authors: Gomes Rafael B. , Oliveira Lucas M. , Britto‐Neto Laurindo S. , Santos Tiago S. , Andrade Gilbran S. , Carvalho Bruno M. , Gonçalves Luiz M. G. 
Published: May 2009

AbstractStylized rendering is the process of generating images or videos that can have the visual appeal of pieces of art, expressing the visual and emotional characteristics of artistic styles. A major problem in stylizing videos is the absence of temporal coherence, something that results in flickering of the structural drawing elements (such as brush strokes or curves), also known asswimming. This article describes the AnimVideo rendering tool that was developed for stylizing videos with temporal coherence. The temporal coherence is achieved by first fully segmenting the input video with a fast fuzzy segmentation algorithm that uses hybrid color spaces and motion information. The result of the segmentation algorithm is used to constrain the result of an optical flow algorithm, given as dense optical flow maps that are then used to correctly move, remove, or add structural drawing elements. The combination of these two methods is referred to asconstrained optical flow, and we also provide the option of initializing the optical flow computation with displacement maps computed by homographies that map objects in adjacent frames. Also, we briefly describe some stylized rendering methods that were implemented in the tool. Finally, experimental results are shown, including snapshots of the tool's interface and illustrative examples of the produced renderings that validates the proposed techniques. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 100–110, 2009.
Temporal motion recognition and segmentation approach
Authors: Ahad Md. Atiqur Rahman , Tan J. K. , Kim H. S. , Ishikawa S. 
Published: May 2009

AbstractSeparating or segmenting complex activities into basic action primitives is important for event recognition and other applications. In this article, simple approaches are presented for appearance‐based action recognition, as well as motion segmentation into its action primitives. Optical flow is computed and split into four channels based on four directions, namely, up, down, left, and right. Based on these four motion vectors, motion history and the corresponding energy templates are generated. These are used for action recognition. Moreover, to segment sequential activity, the temporal motion segmentation (TMS) method is proposed based on the concept of history templates. Based on the total pixel volumes on these templates and their related variations, various directions of the action primitives are segmented temporally. This segmentation method can assist an intelligent system or robot to understand activities and take decisions afterwards. It is a simple and real‐time approach. Based on the presented experiments, this approach can be very useful in various application areas. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 91–99, 2009.
Motion segmentation and activity representation in crowds
Authors: Ma Yunqian , Cisar Petr , Kembhavi Aniruddha 
Published: May 2009

AbstractVideo surveillance of large facilities, such as airports, rail stations, and casinos, is developing rapidly. Cameras installed at such locations often overlook large crowds, which makes problems such as activity and scene understanding very challenging. Traditional activity understanding techniques, which rely on input from lower level processing units dealing with background subtraction, human detection, and tracking, are unable to cope with frequent occlusions in such scenes. We propose a novel spatiotemporal segmentation and activity recognition framework that bypasses these commonly used low‐level modules. We model each local spatiotemporal patch as a dynamic texture. Using a suitable distance metric to compare two local patches based on their estimated dynamic texture parameters, we segment a video into spatiotemporal regions that show similar motion patterns. We are also able to temporally stitch together local regions to form activity streamlines and represent each streamline by its constituent dynamic textures. This allows us to seamlessly perform activity recognition without explicitly detecting individuals in the scene. We demonstrate our framework on multiple datasets and show favorable results compared with the state of the art. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 80–90, 2009.
Computing surfaces via pq‐permutations
Authors: Pulcini Gabriele 
Published: May 2009

AbstractIn algebraic topology, compact two‐dimensional manifolds are usually dealt through a well‐defined class of words denoting polygonal presentations. In this article, we show how to eliminate the useless bureaucracy intrinsic to word‐based presentations by considering very simple combinatorial structures called pq‐permutations. Thanks to their specific effectiveness, pq‐permutations induce a rewriting system P able to compute, in a very easy and intuitive way, the quotient surface associated with any given polygonal presentation. The system P is shown to enjoy both the fundamental computational properties of strong normalization and strict strong confluence. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 132–139, 2009.
A theoretical solution to MAP‐EM partial volume segmentation of medical images
Authors: Wang Su , Lu Hongyu , Liang Zhengrong 
Published: May 2009

AbstractVoxels near tissue borders in medical images contain useful clinical information, but are subject to severe partial volume (PV) effect, which is a major cause of imprecision in quantitative volumetric and texture analysis. When modeling each tissue type as a conditionally independent Gaussian distribution, the tissue mixture fractions in each voxel via the modeled unobservable random processes of the underlying tissue types can be estimated by maximum a posteriori expectation‐maximization (MAP‐EM) algorithm in an iterative manner. This article presents, based on the assumption that PV effect could be fully described by a tissue mixture model, a theoretical solution to the MAP‐EM segmentation algorithm, as opposed to our previous approximation which simplified the posteriori cost function as a quadratic term. It was found out that the theoretically‐derived solution existed in a set of high‐order nonlinear equations. Despite of the induced computational complexity when seeking for optimum numerical solutions to nonlinear equations, potential gains in robustness, consistency and quantitative precision were noticed. Results from both synthetic digital phantoms and real patient bladder MR images were presented, demonstrating the accuracy and efficiency of the presented theoretical MAP‐EM solution. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 111–119, 2009.
Data clustering as an optimum‐path forest problem with applications in image analysis
Authors: Rocha Leonardo Marques , Cappabianco Fábio A. M. , Falcão Alexandre Xavier 
Published: May 2009

AbstractWe propose an approach for data clustering based on optimum‐path forest. The samples are taken as nodes of a graph, whose arcs are defined by an adjacency relation. The nodes are weighted by their probability density values (pdf) and a connectivity function is maximized, such that each maximum of the pdf becomes root of an optimum‐path tree (cluster), composed by samples “more strongly connected” to that maximum than to any other root. We discuss the advantages over other pdf‐based approaches and present extensions to large datasets with results for interactive image segmentation and for fast, accurate, and automatic brain tissue classification in magnetic resonance (MR) images. We also include experimental comparisons with other clustering approaches. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 50–68, 2009.
Surface modification of porous scaffolds with nanothick collagen layer by centrifugation and freeze‐drying
Authors: Chen Guoping , Okamura Aiko , Sugiyama Kazuyuki , Wozniak Michal J. , Kawazoe Naoki , Sato Shigeo , Tateishi Tetsuya 
Published: May 2009

AbstractThree‐dimensional (3D) porous scaffolds constructed from biodegradable synthetic polymers are frequently used in tissue engineering. Their surfaces are hydrophobic and require treatment to be changed to hydrophilic before use in cell culture. We developed a novel surface modification for 3D porous scaffolds made of synthetic polymers by coating the surfaces of the pores with a nanothick collagen layer. First, a collagen aqueous solution was introduced under reduced pressure to fully fill the pores of the PLGA sponges. The collagen‐containing sponges were then centrifuged to remove any excess collagen solution. Finally, the sponges were freeze‐dried to form a thin collagen layer. Scanning electron microscopy observation and water absorption tests demonstrated that the excess collagen was removed; the effect of modification was evident when the collagen‐containing sponges were centrifuged at high centrifugal acceleration. Scanning probe microscopy analysis demonstrated the formation of a nanometer‐thick collagen layer on the PLGA surface. The collagen‐coated PLGA sponges facilitated cell seeding and spatial distribution. The method will be useful for the surface modification of 3D porous scaffolds. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Biomimetic apatite deposition on polymeric microspheres treated with a calcium silicate solution
Authors: Leonor Isabel B. , Balas Francisco , Kawashita Masakazu , Reis Rui L. , Kokubo Tadashi , Nakamura Takashi 
Published: May 2009

AbstractBioactive polymeric microspheres can be prepared by means of coating them with a calcium silicate solution and subsequently soaking in a simulated body fluid (SBF). Such combination should allow for the development of bioactive microspheres for several applications in the medical field including tissue engineering carriers. Four types of polymeric microspheres, with different sizes, were used in this work: (i) ethylene‐vinyl alcohol copolymer (20–30 μm), (ii) polyamide 12 with 10% magnetite (100 μm), (iii) polyamide 12 (10–30 μm) and (iv) polyamide 12 (300 μm). These microspheres were soaked in a calcium silicate solution at 36.5°C for various periods of time under different conditions. Afterwards, they were dried in air at 60 and 100°C for 24 hr. Then, the samples were soaked in SBF for 1, 3, and 7 days. Fourier transformed infrared spectroscopy, thin‐film X‐ray diffraction, and scanning electron microscopy showed that after the calcium silicate treatment and the subsequent soaking in SBF, the microspheres successfully formed an apatite layer on their surfaces in SBF within 7 days due to the formation of silanol groups, which are effective for apatite formation. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Proliferation and differentiation of goat bone marrow stromal cells in 3D scaffolds with tunable hydrophilicity
Authors: Ivirico J. L. Escobar , Salmerón‐Sánchez M. , Ribelles J. L. Gómez , Pradas M. Monleón , Soria J. M. , Gomes M. E. , Reis R. L. , Mano J. F. 
Published: May 2009

AbstractWe have synthesized methacrylate‐endcapped caprolactone networks with tailored water sorption ability, poly(CLMA‐co‐HEA), in the form of three‐dimensional (3D) scaffolds with the same architecture but exhibiting different hydrophilicity character (xHEA=0, 0.3, 0.5), and we investigated the interaction of goat bone marrow stromal cells (GBMSCs) with such structures. For this purpose, GBMSCs were seeded and cultured for 3, 7, 14, 21, and 28 days onto the developed scaffolds. Cells have proliferated throughout the whole scaffold volume. Cell adhesion and morphology were analyzed by SEM, whereas cell viability and proliferation was assessed by MTS test and DNA quantification concluding that numbers of cells increased as a function of the culturing time (until day 14) and also with the hydrophobic content in the samples (from 50 to 100% of CLMA). No significant difference between samples with 100% and 70% of CLMA were detected in some cases. Osteoblastic differentiation was followed by assessing the alkaline phosphatase activity of cells, as well as type I collagen and osteocalcin expressions levels until day 21. The three markers were positive at days 14 and 21 when cells were cultured in 100% CLMA substrates which suggests osteoblastic differentiation of mesenchymal stem cells within these scaffolds. On the other hand, when the CLMA content decreases (until 50%), type I collagen and osteocalcin were positive but ALP was negative indicating that the differentiation process is affected by hydrophilic content. We suggest that such system may be useful to extract information on the effect of materials' wettability on the corresponding biological performance in a 3D environment. Such general insights may be relevant in the context of biomaterials selection for tissue engineering strategies. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
SF2/ASF regulates proteomic diversity by affecting the balance between translation initiation mechanisms
Authors: Blaustein Matías , Quadrana Leandro , Risso Guillermo , Mata Manuel de la , Pelisch Federico , Srebrow Anabella 
Published: May 2009

AbstractPost‐splicing activities have been described for a subset of shuttling serine/arginine‐rich splicing regulatory proteins, among them SF2/ASF. We showed that growth factors activate a Ras‐PI 3‐kinase‐Akt/PKB signaling pathway that not only modifies alternative splicing of the fibronectin EDA exon, but also alters in vivo translation of reporter mRNAs containing the EDA binding motif for SF2/ASF, providing two co‐regulated levels of isoform‐specific amplification. Translation of most eukaryotic mRNAs is initiated via the scanning mechanism, which implicates recognition of the m7G cap at the mRNA 5′‐terminus by the eIF4F protein complex. Several viral and cellular mRNAs are translated in a cap‐independent manner by the action of cis‐acting mRNA elements named internal ribosome entry sites that direct internal ribosome binding to the mRNA. Here we use bicistronic reporters that generate mRNAs carrying two open reading frames, one translated in a cap‐dependent manner while the other by internal ribosome entry site‐dependent initiation, to show that in vivo over‐expression of SF2/ASF increases the ratio between cap‐dependent and internal ribosome entry site‐dependent translation. Consistently, knocking‐down of SF2/ASF causes the opposite effect. Changes in expression levels of SF2/ASF also affect alternative translation of an endogenous mRNA, that one coding for fibroblast growth factor‐2. These results strongly suggest a role for SF2/ASF as a regulator of alternative translation, meaning the generation of different proteins by the balance among these two translation initiation mechanisms, and expand the known potential of SF2/ASF to regulate proteomic diversity to the translation field. J. Cell. Biochem. 107: 826–833, 2009. © 2009 Wiley‐Liss, Inc.
Regulator of differentiation 1 (ROD1) binds to the amphipathic C‐terminal peptide of thrombospondin‐4 and is involved in its mitogenic activity
Authors: Sadvakassova Gulzhakhan , Dobocan Monica C. , Difalco Marcos R. , Congote Luis F. 
Published: May 2009

AbstractThe matrix protein thrombospondin‐4 has an acidic amphipathic C‐terminal peptide (C21) which stimulates erythroid cell proliferation. Here we show that C21 stimulates red cell formation in anemic mice in vivo. In vitro experiments indicated that the peptide‐mediated increase of erythroid colony formation in cultures of human CD34+ hematopoietic progenitor cells was possible only under continuous presence of erythropoietin. In the absence of this cytokine, C21 stimulated exclusively myeloid colony formation. Therefore, the peptide is not a specific erythroid differentiation factor. In fact, it is mitogenic in non‐erythroid cells, such as skin fibroblasts and kidney epithelial cells. In erythroleukemic TF‐1 cells, it actually decreased the production of the erythroid differentiation marker glycophorin A. C21‐affinity chromatography revealed regulator of differentiation 1 (ROD1) as a major C21‐binding protein. ROD1 is the hematopoietic cell paralog of polypyrimidine tract binding proteins (PTBs), RNA splice regulators which regulate differentiation by repressing tissue‐specific exons. ROD1 binding to C21 was strongly inhibited by synthetic RNAs in the order poly A > poly U > poly G = poly C and was weakly inhibited by a synthetic phosphorylated peptide mimicking the C‐terminal domain of RNA polymerase II. Cellular overexpression or knockdown experiments of ROD1 suggest a role for this protein in the mitogenic activity of C21. Since the nuclear proteins ROD1 and PTBs regulate differentiation at a posttranscriptional level and there is a fast nuclear uptake of C21, we put forward the idea that the peptide is internalized, goes to the nucleus and maintains cells in a proliferative state by supporting ROD1‐mediated inhibition of differentiation. J. Cell. Physiol. 220: 672–679, 2009. © 2009 Wiley‐Liss, Inc.
Mechanistic elucidation and evaluation of biosorption of metal ions by grapefruit peel using FTIR spectroscopy, kinetics and isotherms modeling, cations displacement and EDX analysis
Authors: Iqbal Muhammad , Schiewer Silke , Cameron Randall 
Published: May 2009

AbstractBACKGROUND: The performance and mechanism of the biosorptive removal of Ni2+ and Zn2+ from aqueous solution using grapefruit peel (GFP) as a new biosorbent was investigated by using different experimental approaches, such as potentiometric titration, Fourier transform infrared (FTIR) and energy‐dispersive X‐ray spectroscopy (EDX) analysis, chemical blocking of functional groups and concomitant release of cations (Ca2+, Mg2+, Na+, K+) from GFP with metal (Ni2+, Zn2+) uptake.RESULTS: GFP removed Ni2+ and Zn2+ rapidly, with 84.73% and 92.46% of the equilibrium sorption being reached in 30 min for Ni2+ and Zn2+, respectively. The equilibrium process was described well by the Langmuir isotherm model, with maximum sorption capacity of 1.33 and 1.51 meq g−1 for Ni2+ and Zn2+, respectively. Release of cations (Ca2+, Mg2+, Na+, K+) and protons H+ from GFP during uptake of Ni2+ and Zn2+ and EDX analysis of GFP before and after metal sorption revealed that the main mechanism of sorption was ion exchange. FTIR spectroscopy showed that carboxyl and hydroxyl groups were involved in the sorption of Ni2+ and Zn2+. Blocking of these groups revealed that carboxylic group was responsible for 78.57% and 73.31% of Ni2+ and Zn2+ removal, respectively whereas 22.63% and 28.54% was due to the hydroxyl group. The GFP could be regenerated using 0.1 mol L−1 HCl, with more than 98% metal recovery and reused for five cycles without any significant loss in its initial sorption capacity.CONCLUSIONS: The study suggests that GFP has promising potential for use as an efficient and cost‐effective biosorbent for the removal and recovery of Ni2+ and Zn2+ from aqueous solution. Copyright © 2009 Society of Chemical Industry
Sonography of thyroid nodules with peripheral calcifications
Authors: Park Minjung , Shin Jung Hee , Han Boo‐Kyung , Ko Eun Young , Hwang Hye Sun , Kang Seok Seon , Kim Jung Han , Oh Young Lyun 
Published: May 2009

AbstractPurpose.This study was designed to assess the role of sonography (US) in the differentiation of benign from malignant thyroid nodules with peripheral calcifications.Methods.Sixty‐four thyroid nodules with peripheral calcifications that were detected on US were included in the study. Nineteen nodules (30%) were benign, and 45 nodules (70%) were malignant. We retrospectively compared the US findings of the benign and malignant nodules, including interruption, thickening (≥0.5 mm and over more than 50% of the circumference) of calcifications, internal echogenicity, margin, and presence of cystic change, size, and shape. Univariate and multivariate logistic regression analyses were performed.Results.Interruption of peripheral calcifications was more common in malignant nodules (84%) than in benign nodules (53%) (OR, 7.9; 95% CI, 1.3–48.4; p < 0.05). Thickening of the peripheral calcification was seen more frequently in malignant nodules (64%) than in benign nodules (11%) (OR, 14.7; 95% CI, 1.8–117.5; p < 0.05). For internal echogenicity, malignant nodules (58%) were more often hypoechoic than benign nodules (OR, 23.6; 95% CI, 2.2–256.3; p < 0.01). The mean tumor size was 1.1 cm for malignant nodules and 1.2 cm for benign nodules (p > 0.05). There were no significant differences for the presence or absence of cystic change, size, shape, and margin between malignant and benign nodules.Conclusion.Interruption and thickening of peripheral calcifications and decreased internal echogenicity of a thyroid nodule with peripheral calcifications are in favor of malignancy. © 2009 Wiley Periodicals, Inc. J Clin Ultrasound 2009