263 research outputs found
Earthquake load attenuation using EPS geofoam buffers in rigid wall applications
The paper is a synthesis of previously published work by the authors that is focused on the use of expanded polystyrene (EPS) geofoam buffers for seismic load attenuation against rigid basement and soil retaining walls. The paper begins with a brief description of the first documented field application followed by a description of physical 1 m-high reduced-scale shaking table tests that provided the first proof of concept . Next, details of the development and verification of a displacement-based model and a FLAC numerical model are described and simulation results that were verified against the physical shaking table tests presented. The numerical results include simulations using simple linear elastic constitutive models for the EPS buffers and granular soil backfill and more complex non-linear hysteretic models. Finally, the verified FLAC model was used to develop a series of preliminary design charts for the selection of a suitable seismic buffer based on characteristics of the design earthquake accelerogram
Detection Systems in Immunohistochemistry
Immunohistochemistry (IHC) is a process of selectively imaging antigens in cells or tissue sections by exploiting antibody specificity. This technique is widely used in diagnostic pathology and research experiments for tracking specific molecular markers characteristic of a particular cell type or cellular events such as cancerous cell development, cell proliferation, or apoptosis. Visualizing the target antigen following an antibody-antigen interaction is accomplished by different detection systems. In the simplest instance, primary antibody directly conjugated to an enzyme is responsible for both specifically binding to the antigen and catalyzing a color-producing reaction. Alternatively, complex detection systems could be designed to profoundly improve minimal detection level of the antigen. During the past years, there has been a considerable improvement in designing and introduction of new and highly sensitive detection systems. The choice of an IHC detection system is a compromise of a variety of variables including desired sensitivity, cost, and the time needed for an IHC staining to be performed. This chapter covers the immunohistochemistry detection systems with emphasis on their principle, history, advantages, and limitations and delineates factors needed to be considered for choosing an appropriate detection system for IHC applications
In vivo effects of calcitriol on phenotypic and functional properties of Dendritic cells
Background: Dendritic cells (DCs) play a central role in the initiation and expansion of T cell mediated immune responses with potential immunotherapy application. The compounds which have the ability to induce immunomodulatory effects on DCs may be employed for the treatment of immunopathologic conditions such as autoimmune diseases. Objective: The aim of this study was to investigate the in vivo effects of calcitriol (active form of vitamin D3) on DCs. Methods: 0.1 microgram calcitriol was injected intra-peritoneally into C57BL/6 mice every other day within 3 weeks, and spleen DCs were extracted by magnetic beads. The phenotypic and functional properties of DCs were studied by flow cytometry and mixed lymphocyte reaction (MLR), respectively. Results: The expression of CD86 and MHC II, as maturation markers and costimulatory molecules were significantly decreased (p=0.028 and p=0.047, respectively) while CD11b expression, as a marker of mice myeloid DCs which mostly induces Th2 cytokine profile, was significantly increased (p=0.011). Allogeneic T cell stimulation in MLR was also significantly inhibited in comparison with the control groups (p<0.05). Conclusion: Our data indicate that in vivo calcitriol administration inhibits maturation and activation of DCs in the same manner as in vitro conditions
Shaking Table Methodology and Instrumentation for Reinforced Soil Retaining Walls
The paper describes a testing methodology, instrumentation array and example data interpretation for reduced-scale geosynthetic reinforced soil (GRS) wall models built on a large shaking table. The testing program is unique in the literature because of the large number of different instruments deployed and the use of Particle Image Velocimetry (PIV) analysis of imagery captured using a high speed camera. The models are instrumented with strain gauges and extensometers attached to the geogrid reinforcing layers, LVDTs attached to the facing panel, load cells at the wall toe, reinforcement-facing load measurement, and accelerometers in the backfill and along the facing. Example measurements are reported that demonstrate the value of the experimental technique to better understand the mechanics of these systems under simulated earthquake
Profiling and quantitative evaluation of three Nickel-Coated magnetic matrices for purification of recombinant proteins: lelpful hints for the optimized nanomagnetisable matrix preparation
<p>Abstract</p> <p>Background</p> <p>Several materials are available in the market that work on the principle of protein magnetic fishing by their histidine (His) tags. Little information is available on their performance and it is often quoted that greatly improved purification of histidine-tagged proteins from crude extracts could be achieved. While some commercial magnetic matrices could be used successfully for purification of several His-tagged proteins, there are some which have been proved to operate just for a few extent of His-tagged proteins. Here, we address quantitative evaluation of three commercially available Nickel nanomagnetic beads for purification of two His-tagged proteins expressed in <it>Escherichia coli </it>and present helpful hints for optimized purification of such proteins and preparation of nanomagnetisable matrices.</p> <p>Results</p> <p>Marked differences in the performance of nanomagnetic matrices, principally on the basis of their specific binding capacity, recovery profile, the amount of imidazole needed for protein elution and the extent of target protein loss and purity were obtained. Based on the aforesaid criteria, one of these materials featured the best purification results (SiMAG/N-NTA/Nickel) for both proteins at the concentration of 4 mg/ml, while the other two (SiMAC-Nickel and SiMAG/CS-NTA/Nickel) did not work well with respect to specific binding capacity and recovery profile.</p> <p>Conclusions</p> <p>Taken together, functionality of different types of nanomagnetic matrices vary considerably. This variability may not only be dependent upon the structure and surface chemistry of the matrix which in turn determine the affinity of interaction, but, is also influenced to a lesser extent by the physical properties of the protein itself. Although the results of the present study may not be fully applied for all nanomagnetic matrices, but provide a framework which could be used to profiling and quantitative evaluation of other magnetisable matrices and also provide helpful hints for those researchers facing same challenge.</p
Improved efficacy of a dendritic cell-based vaccine against a murine model of colon cancer: The helper protein effect
Purpose Targeted immunotherapy using dendritic cells (DCs) has been employed in numerous investigations aiming at combating neoplasms. We previously showed that copulsing of an antigen with a helper protein could considerably enhance antigen presenting capacity of ex vivo-generated DCs. In this study, we attempted to administer an effective treatment in a murine model of colon cancer with DCs pulsed with the mixture of a tumor-specific gp70-derived peptide (AH1) and a helper protein, ovalbumin (OVA). Materials and Methods First, the presence of gp70 in CT26 tumor cells and tumor tissues was verified using immunofluorescence and Western blot analyses. Next, DCs were purified from normal mice, loaded ex vivowith AH1 and OVA (DC-Pep-OVA), and injected into tumor-bearing mice. Tumor volume, in vitro antigen (Ag)-specific proliferation of splenic cells, and survival rate were measured to determine the efficacy of DC-Pep-OVA. As the control groups, tumor-bearing mice were vaccinated with DC-Pep, unpulsed DC, and DCs loaded with a mixture of OVA and an irrelevant peptide (P15), or were not vaccinated at all. Results DC-Pep-OVA showed superior efficacy over other groups, as indicated by smaller tumor volume, higher Ag-specific proliferation rate of splenic cells, and prolonged survival. Conclusion Overall, in the present study we showed for the first time that DCs copulsed with AH1 (tumor Ag) and OVA (helper molecule) could be considered as potentially robust weapons for use in future antitumor immunotherapies. © 2015 by the Korean Cancer Association
Immunomodulatory effects of human amniotic epithelial cells on naive CD4+ T cells from women with unexplained recurrent spontaneous abortion
Abstract
Introduction
Immune imbalance at the maternal-fetal interface plays a fundamental role in the pathogenesis of unexplained recurrent spontaneous abortion (URSA). Human amniotic epithelial cells (hAECs) possess pregnancy-friendly immunomodulatory effects. Here, we investigated how function of naive CD4+ T cells from URSA patients is affected by hAECs.
Methods
Phenotypic characteristics of hAECs were determined by flow cytometry and their effect on proliferation of allogeneic peripheral blood mononuclear cells (PBMCs) was evaluated by a BrdU cell proliferation assay. Naive CD4+ T cells were isolated from 25 URSA patients and 5 healthy women and co-cultured with hAECs. Immunomodulatory effects of hAECs on cytokines profile, proliferation of stimulated CD4+ T cells and induction of regulatory T cells (Tregs) were assessed by ELISA and flow cytometry, respectively. Functional competency of Tregs was evaluated in an allogeneic mixed lymphocyte reaction (MLR) system.
Results
hAECs did not elicit allogeneic proliferative responses of PBMCs, inhibited proliferation of naive CD4+ T cells, induced production of Th2 and suppressed production of Th1 and Th17 cytokines. hAECs showed the ability to induce differentiation of Tregs and production of transforming growth factor-beta1 (TGF-β1) and interleukin-10 (IL-10). This ability was found to be superior in control subjects compared to URSA patients. Indeed, Tregs generated in the presence of hAECs expressed higher levels of CTLA-4 compared to Tregs generated in their absence and restrained the proliferation of autologus PBMCs in MLR system.
Conclusion
Based on these findings, hAECs can be considered as one potential candidate in immunotherapy of patients with URSA.
Keywords Immunomodulatory effects Amniotic epithelial cells
Naive T cells Unexplained recurrent spontaneous abortio
Investigation of the Lambda Parameter for Language Modeling Based Persian Retrieval
Language modeling is one of the most powerful methods in information retrieval. Many language modeling based retrieval systems have been developed and tested on English collections. Hence, the evaluation of language modeling on collections of other languages is an interesting research issue. In this study, four different language modeling methods proposed by Hiemstra [1] have been evaluated on a large Persian collection of a news archive. Furthermore, we study two different approaches that are proposed for tuning the Lambda parameter in the method. Experimental results show that the performance of language models on Persian text improves after Lambda Tuning. More specifically Witten Bell method provides the best results
Culture density of menstrual blood-derived stromal/stem cells determines the quality of T cell responses: An experimental study
Background: Menstrual blood-derived stromal/stem cells (MenSCs) are a new population of refreshing and highly proliferative stem cells. Immunomodulatory effects of MenSCs profoundly depend on their relative density.
Objective: To find whether MenSCs cultured at varying numbers would differentially affect the allogenic peripheral blood mononuclear cells (PBMCs) key features.
Materials and Methods: PBMCs were co-cultured with various MenSCs numbers. PBMCs proliferation was investigated via 3H-thymidine incorporation. Flow cytometry was used to assess human leukocyte antigen (HLA)-DR, HLA-ABC, HLA-G, and costimulatory markers on MenSCs and the percentage of regulatory T cells (Tregs) among PBMCs. The concentration of cytokines was determined in supernatant of co-cultures.
Results: The support of PBMCs proliferation at low MenSCs densities correlated with higher levels of pro-inflammatory interferon gamma (IFN-γ) in MenSCs/PBMCs co-culture and increased expression of HLA-DR by MenSCs. On the other hand, the suppressive property of MenSCs at higher densities was independent of Treg frequency, but correlated with a high concentration of Interleukin (IL)-6 and IL-10 in the co-cultures.
Conclusion: Totally, at different seeding densities, MenSCs could differentially interact with PBMCs leading to significant changes in the level of anti- and/or pro-inflammatory factors. These preliminary in vitro results are suggested to be taken into consideration in experimental models of MenSC-based immunomodulation. Nonetheless, for efficient utilization of MenSCs anti-inflammatory features in pre-clinical disease models, we still need to broaden our knowledge on MenSC-immune system cross-talk; this could play a part in designing more optimized MenSCs injection modalities in the case of future pre-clinical and subsequently clinical settings.
Key words: Menstrual, Stromal cells, T cell response, Interferon
The effect of human amniotic epithelial cell on dendritic cell differentiation of peripheral blood monocytes: An experimental study
Background: The amniotic membrane plays an important role in maintaining a healthy pregnancy. The main population cells from amniotic membrane include human amnion epithelial cells (hAECs) which have been shown to possess immunomodulatory properties.
Objective: The proximity of hAECs with monocyte leads to the generation of tollerogenic dendritic cells.
Materials and Methods: hAECs were obtained from normal pregnancy. Peripheral blood monocytes were isolated by anti-CD14 MACS method. Co-cultures of monocytes and hAECs were established in Transwell chambers supplemented with granulocytemacrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) in the absence and presence of lipopolysaccharide (LPS) to produce immature and mature DCs, respectively. Immunophenotyping of the obtained DCs was done through flow cytometry and the production of cytokines was measured by ELISA. Mixed leukocyte Reaction (MLR) was also performed for the functional assessment of DCs.
Results: Immunophenotyping of [hAECs - Immature DC (iDC)] and [hAECs - iDC] + LPS cells revealed that the expression of CD1a, CD80, CD86, CD40, HLA-DR, and CD83 markers showed no significant difference as compared with the control group (iDCs and mDCs alone). In the [hAECs-iDCs] + LPS cells, the percentage of CD14 cells at the ratio of 1:2.5 showed significant differences compared to the control group. The production of IL-10 and IL-12 showed no significant difference in any of the cultures as compared to the control groups. Also, co-cultured DCs did not inhibit proliferation of lymphocyte.
Conclusion: Our findings show that factors secreted from cultured hAECs are unable to generate of tollerogenic dendritic cells. To achieve a better understanding of other mechanisms more investigations are needed.
Key words: Amniotic membrane, Dendritic cells, Human placenta, Immunomodulation, Monocyte
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