Spatio-temporal pattern analysis of managed forest landscapes : a simulation approach

This study dealt with research problems at the landscape level. The objectives of this thesis were to develop tools to study and characterize landscapes and to interface with a geographic information system (GIS), to evaluate landscape indices, and to examine development of forest cutting patterns under different cutting methods and explore alternative forest management strategies. A computer program was developed for simulation and analysis of landscape patterns. The primary applications of the computer program were (1) to quantify spatial patterns of landscapes, (2) to perform experiments with different silvicultural strategies and forecast the consequences of management activities, (3) to examine the behavior of landscape indices without having a large number of landscape samples, (4) to interface with and to complement GIS in terms of ecological analysis, and (5) to serve as a base on which GIS-related landscape models could built. Many extant landscape indices were reviewed, and some new indices proposed. Each was evaluated in terms of its ability to distinguish four test synthetic landscapes with distinct spatial patterns. Fractal dimension, patchiness index, dispersal index, and two fragmentation indices (i.e., the forest interior area and the largest forest patch size) appeared to be most sensitive to spatial variations among the test landscape mosaics, and may be most useful to study and quantify the landscape pattern. On the other hand, some commonly-used landscape indices, contagion and dominance, could not distinguish variations in distinct landscape patterns. The simulation program and the landscape indices were then used to study landscape patterns generated by different forest cutting methods. The results indicated that different cutting designs may produce landscapes with distinct characteristics. Landscapes were clearly less fragmented when larger sizes of cut-units were used. When a stream system was included in the landscape structure, the behavior of many landscape characteristics changed. The results suggested that simple landscape models (i.e., the checkerboard model and random model) may lead to misleading interpretations of landscape patterns

Agent based mobile negotiation for personalized pricing of last minute theatre tickets

This is the post-print version of the final paper published in Expert Systems with Applications. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2012 Elsevier B.V.This paper proposes an agent based mobile negotiation framework for personalized pricing of last minutes theatre tickets whose values are dependent on the time remaining to the performance and the locations of potential customers. In particular, case based reasoning and fuzzy cognitive map techniques are adopted in the negotiation framework to identify the best initial offer zone and adopt multi criteria decision in the scoring function to evaluate offers. The proposed framework is tested via a computer simulation in which personalized pricing policy shows higher market performance than other policies therefore the validity of the proposed negotiation framework.The Ministry of Education, Science and Technology (Korea

Perfusable micro-vascularized 3D tissue array for high-throughput vascular phenotypic screening

Microfluidic organ-on-a-chip technologies have enabled construction of biomimetic physiologically and pathologically relevant models. This paper describes an injection molded microfluidic platform that utilizes a novel sequential edge-guided patterning method based on spontaneous capillary flow to realize three-dimensional co-culture models and form an array of micro-vascularized tissues (28 per 1 × 2-inch slide format). The MicroVascular Injection-Molded Plastic Array 3D Culture (MV-IMPACT) platform is fabricated by injection molding, resulting in devices that are reliable and easy to use. By patterning hydrogels containing human umbilical endothelial cells and fibroblasts in close proximity and allowing them to form vasculogenic networks, an array of perfusable vascularized micro-tissues can be formed in a highly efficient manner. The high-throughput generation of angiogenic sprouts was quantified and their uniformity was characterized. Due to its compact design (half the size of a 96-well microtiter plate), it requires small amount of reagents and cells per device. In addition, the device design is compatible with a high content imaging machine such as Yokogawa CQ-1. Furthermore, we demonstrated the potential of our platform for high-throughput phenotypic screening by testing the effect of DAPT, a chemical known to affect angiogenesis. The MV-IMPACT represent a significant improvement over our previous PDMS-based devices in terms of molding 3D co-culture conditions at much higher throughput with added reliability and robustness in obtaining vascular micro-tissues and will provide a platform for developing applications in drug screening and development.This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIT) (No. 2021R1A3B1077481). This study was also supported by a grant of the Korean Health Technol‑ ogy R&D Project, Ministry of Health & Welfare, Republic of Korea (Grant No. HP20C0146010020), and by National Institutes of Health (R01HL141857 to YKH)

Embedding persuasive features into policy issues:Implications to designing public participation processes

Public participation is one of the most important tasks for policy making processes, and public authorities are lacking ideas on designing public participation processes facilitating active citizen participation. Based on a persuasion theory, this paper examines if policy issues embedded with persuasive features draw more attention, longer elaboration time and more participation. Particularly preference matching, location matching, social proof and authority are identified as persuasive features in e-participation context and propositions on their impacts on citizens’ participation processes are developed. A prototype mobile participation tool is developed to test the propositions and tested by 80 experiment participants in the UK and Turkey. The findings indicate that the mixture of central and peripheral features is most effective in drawing participation while single feature has limitations. This study also argues that the design of e-participation tools needs to consider the psychological aspects of citizens for motivating their participations

Pneumatically Actuated Microfluidic Platform for Reconstituting 3D Vascular Tissue Compression

In vivo, blood vessels constitutively experience mechanical stresses exerted by adjacent tissues and other structural elements. Vascular collapse, a structural failure of vascular tissues, may stem from any number of possible compressive forces ranging from injury to tumor growth and can promote inflammation. In particular, endothelial cells are continuously exposed to varying mechanical stimuli, internally and externally, resulting in blood vessel deformation and injury. This study proposed a method to model biomechanical-stimuli-induced blood vessel compression in vitro within a polydimethylsiloxane (PDMS) microfluidic 3D microvascular tissue culture platform with an integrated pneumatically actuated compression mechanism. 3D microvascular tissues were cultured within the device. Histological reactions to compressive forces were quantified and shown to be the following: live/dead assays indicated the presence of a microvascular dead zone within high-stress regions and reactive oxygen species (ROS) quantification exhibited a stress-dependent increase. Fluorescein isothiocyanate (FITC)-dextran flow assays showed that compressed vessels developed structural failures and increased leakiness; finite element analysis (FEA) corroborated the experimental data, indicating that the suggested model of vascular tissue deformation and stress distribution was conceptually sound. As such, this study provides a powerful and accessible in vitro method of modeling microphysiological reactions of microvascular tissues to compressive stress, paving the way for further studies into vascular failure as a result of external stress

Genome-Wide Profiling of Cervical RNA-Binding Proteins Identifies Human Papillomavirus Regulation of RNASEH2A Expression by Viral E7 and E2F1

High-risk HPV infections lead to development of cervical cancer. This study identified the differential expression of 16 novel genes (LY6K, FAM83A, CELSR3, ASF1B, IQGAP3, SEMA3F, CLDN10, MSX1, CXCL5, ASRGL1, ELAVL2, GRB7, KHSRP, NOVA1, PTBP1, and RNASEH2A) in HPV-infected cervical tissue samples and keratinocytes. Eight of these genes (CDKN2A, ELAVL2, GRB7, HSPB1, KHSRP, NOVA1, PTBP1, and RNASEH2A) encode RNA-binding proteins. Further studies indicated that both HPV16 and HPV18 infections lead to the aberrant expression of selected RBP-encoding genes. We found that viral E6 and E7 decrease NOVA1 expression but that E7 increases RNASEH2A expression via E2F1. The altered expression of these genes may be utilized as biomarkers for high-risk (HR)-HPV carcinogenesis and progression.RNA-binding proteins (RBPs) control mRNA processing, stability, transport, editing, and translation. We recently conducted transcriptome analyses comparing normal (i.e., healthy) cervical tissue samples with human papillomavirus (HPV)-positive cervical cancer tissue samples and identified 614 differentially expressed protein-coding transcripts which are enriched in cancer-related pathways and consist of 95 known RBPs. We verified the altered expression of 26 genes with a cohort of 72 cervical samples, including 24 normal cervical samples, 25 cervical intraepithelial neoplasia grade 2 (CIN2) and CIN3 samples, and 23 cervical cancer tissue samples. LY6K (lymphocyte antigen 6 complex locus K), FAM83A (family member with sequence similarity 83), CELSR3, ASF1B, IQGAP3, SEMA3F, CLDN10, MSX1, CXCL5, ASRGL1, ELAVL2, GRB7, KHSRP, NOVA1, PTBP1, and RNASEH2A were identified as novel candidate genes associated with cervical lesion progression and carcinogenesis. HPV16 or HPV18 infection was found to alter the expression of 8 RBP genes (CDKN2A, ELAVL2, GRB7, HSPB1, KHSRP, NOVA1, PTBP1, and RNASEH2A) in human vaginal and foreskin keratinocytes. Both viral E6 and E7 decreased NOVA1 expression, but only E7 increased the expression of RNASEH2A in an E2F1-dependent manner. Proliferating cell nuclear antigen (PCNA) directs RNASEH2 activity with respect to DNA replication by removing the RNA primers to promote Okazaki fragment maturation, and two factors are closely associated with neoplasia progression. Therefore, we predict that the induction of expression of RNASEH2A via viral E7 and E2F1 may promote DNA replication and cancer cell proliferation