Search results for: hematopoietic stem cell transplantation

Authors: Ge Zheng, Jun Peng

Abstract:

Unbalanced power output from individual cells of Proton Exchange Membrane Fuel Cell (PEMFC) has direct effects on PEMFC stack performance, in particular under transient operation. In the paper, a multi-layer ANN (Artificial Neural Network) model Radial Basis Functions (RBF) has been developed for predicting cells' output profiles by applying gas supply parameters, cooling conditions, temperature measurement of individual cells, etc. The feed-forward ANN model was validated with experimental data. Influence of relevant parameters of RBF on the network accuracy was investigated. After adequate model training, the modelling results show good correspondence between actual measurements and reconstructed output profiles. Finally, after the model was used to optimize the stack output performance under steady-state and transient operating conditions, it suggested that the developed ANN control model can help PEMFC stack to have obvious improvement on power output under fast acceleration process.

Keywords: proton exchange membrane fuel cell, PEMFC, artificial neural network, ANN, cell output profile, transient

Procedia PDF Downloads 158

Authors: Ablo Paul Igor Hounzandji, Benoit Lafleur, Annie DesRochers

Abstract:

Introduction: Populus tremuloides [Michx] regenerates rapidly and abundantly by root suckering after harvest, creating stands with interconnected stems. Pre-commercial thinning can be used to concentrate growth on fewer stems to reach merchantability faster than un-thinned stands. However, conventional thinning methods are typically designed to reach even spacing between residual stems (1,100 stem ha⁻¹, evenly distributed), which can lead to treated stands consisting of weaker/smaller stems compared to the original stands. Considering the nature of P. tremuloides's regeneration, with large underground biomass of interconnected roots, aiming to keep the most vigorous and largest stems, regardless of their spatial distribution, inverted diameter-limit thinning could be more beneficial to post-thinning stand productivity because it would reduce the imbalance between roots and leaf area caused by thinning. Aims: This study aimed to compare stand and stem productivity of P. tremuloides stands thinned with a conventional thinning treatment (CT; 1,100 stem ha⁻¹, evenly distributed), two levels of inverted diameter-limit thinning (DL1 and DL2, keeping the largest 1100 or 2200 stems ha⁻¹, respectively, regardless of their spatial distribution) and a control unthinned treatment. Because DL treatments can create substantial or frequent gaps in the thinned stands, we also aimed to evaluate the potential of this treatment to recreate mixed conifer-broadleaf stands by fill-planting Picea glauca seedlings. Methods: Three replicate 21 year-old sucker-regenerated aspen stands were thinned in 2010 according to four treatments: CT, DL1, DL2, and un-thinned control. Picea glauca seedlings were underplanted in gaps created by the DL1 and DL2 treatments. Stand productivity per hectare, stem quality (diameter and height, volume stem⁻¹) and survival and height growth of fill-planted P. glauca seedlings were measured 8 year post-treatments. Results: Productivity, volume, diameter, and height were better in the treated stands (CT, DL1, and DL2) than in the un-thinned control. Productivity of CT and DL1 stands was similar 4.8 m³ ha⁻¹ year⁻¹. At the tree level, diameter and height of the trees in the DL1 treatment were 5% greater than those in the CT treatment. The average volume of trees in the DL1 treatment was 11% higher than the CT treatment. Survival after 8 years of fill planted P. glauca seedlings was 2% greater in the DL1 than in the DL2 treatment. DL1 treatment also produced taller seedlings (+20 cm). Discussion: Results showed that DL treatments were effective in producing post-thinned stands with larger stems without affecting stand productivity. In addition, we showed that these treatments were suitable to introduce slower growing conifer seedlings such as Picea glauca in order to re-create or maintain mixed stands despite the aggressive nature of P. tremuloides sucker regeneration.

Keywords: Aspen, inverted diameter-limit, mixed forest, populus tremuloides, silviculture, thinning

Procedia PDF Downloads 138

Authors: Bruno Cossu, Elio Carlo

Abstract:

The invention (patent pending) relates to the field of devices aimed to harness wave energy (WEC) especially for artificial upwelling, forced downwelling, production of compressed air. In its basic form, the pump consists of a hydro-pneumatic machine, driven by wave energy, characterised by the fact that it has no moving mechanical parts, and is made up of only two structural components: an hollow body, which is open at the bottom to the sea and partially immersed in sea water, and a tube, both joined together to form a single body. The shape of the hollow body is like a mushroom whose cap and stem are hollow; the stem is open at both ends and the lower part of its surface is crossed by holes; the tube is external and coaxial to the stem and is joined to it so as to form a single body. This shape of the hollow body and the type of connection to the tube allows the pump to operate simultaneously as an air compressor (OWC) on the cap side, and as an airlift on the stem side. The pump can be implemented in four versions, each of which provides different variants and methods of implementation: 1) firstly, for the artificial upwelling of cold, deep ocean water; 2) secondly, for the lifting and transfer of these waters to the place of use (above all, fish farming plants), even if kilometres away; 3) thirdly, for the forced downwelling of surface sea water; 4) fourthly, for the forced downwelling of surface water, its oxygenation, and the simultaneous production of compressed air. The transfer of the deep water or the downwelling of the raised surface water (as for pump versions indicated in points 2 and 3 above), is obtained by making the water raised by the airlift flow into the upper inlet of another pipe, internal or adjoined to the airlift; the downwelling of raised surface water, oxygenation, and the simultaneous production of compressed air (as for the pump version indicated in point 4), is obtained by installing a venturi tube on the upper end of the pipe, whose restricted section is connected to the external atmosphere, so that it also operates like a hydraulic air compressor (trompe). Furthermore, by combining one or more pumps for the upwelling of cold, deep water, with one or more pumps for the downwelling of the warm surface water, the system can be used in an Ocean Thermal Energy Conversion plant to supply the cold and the warm water required for the operation of the same, thus allowing to use, without increased costs, in addition to the mechanical energy of the waves, for the purposes indicated in points 1 to 4, the thermal one of the marine water treated in the process.

Keywords: air lifted upwelling, fish farming plant, hydraulic air compressor, wave energy converter

Procedia PDF Downloads 143

Authors: Emad A. Shalaby

Abstract:

Cancer is a disease that causes abnormal cell proliferation and invades nearby tissues. Lung cancer is the second most frequent cancer worldwide. Natural anti-cancer drugs have been developed with low side effects and toxicity. Citrus peels and extracts have been demonstrated to have significant pharmacological and physiological effects as a result of the high concentration of phenolic compounds found in citrus fruits, particularly peels. Tangerine peels can serve as an effective source of bioactive substances such as phenolics, flavonoids, and catechins, which have antioxidant, antibacterial, anticancer, and anti-inflammatory properties. Consequently, this work aims to determine the anticancer activity of ethanol extract of Tangerine peels against the A549 cell line and identify the phenolic compound profile (19 compounds) by using HPLC. Anticancer and antioxidant potentials of the extract were evaluated by MTT assay and TLC- TLC-bioautography sprayed with DPPH reagent, respectively. The obtained results revealed that tangerine peel extract showed significant activity against the A549 cell line with IC50 of 97.66 μg/mL. HPLC analysis proved that the highest concentration is naringenin 464.05 mg/g. More studies indicate that naringenin has significant anticancer potential on A549 cancer cells. The results showed that naringenin binds t0 EGFR protein in A549 with high binding affinity and thus may reduce lung cancer cell migration and enhance the apoptosis of cancer cells. From the obtained results it could be concluded that tangerine peel extract is an effective anti-cancer agent that may potentially serve as a natural therapeutic option for lung cancer treatment.

Keywords: tangerine peel, A549 cell line, anticancer, naringenin, HPLC analysis, naringenin, TLC bioautography

Procedia PDF Downloads 55

Authors: A. P. Attanayake, K. A. P. W. Jayatilaka, L. K. B. Mudduwa, C. Pathirana

Abstract:

Triggering of β-cell regeneration is a recognized therapeutic strategy for the treatment of type 1 diabetes mellitus. One such approach to foster restoration and regeneration of β-cells is from exogenous natural extracts. The aim of the present study was to investigate and compare the β-cell regenerative potentials of the extracts of Spondias pinnata (Linn. f.) Kurz, Coccinia grandis (L.) Voigt and Gmelina arborea Roxb. in alloxan induced diabetic rats. Wistar rats were divided in to six groups (n=6); healthy untreated rats, alloxan induced diabetic untreated rats (150 mg/kg, ip), diabetic rats receiving the extracts of S. pinnata (1.0 g/kg), C. grandis (0.75 g/kg), G. arobrea (1.00 g/kg) and diabetic rats receiving glibenclamide (0.5 mg/kg) for 30 days. The assessment of selected biochemical parameters, histopathology and immunohistochemistry in the pancreatic tissue were done on the 30th day. The reduction in the percentage of HbA1C was in the decreasing order of C. grandis (35%), G. arborea (31%) and S. pinnata (29%) in alloxan induced diabetic rats (p< 0.05). The concentration of serum fructosamine, insulin and C-peptide were decreased significantly in a decreasing order of C. grandis (30%, 72%, 51%), G. arborea (25%, 44%, 44%) and S. pinnata (27%, 34%, 24%) in alloxan induced diabetic rats (p < 0.05). The extent of β-cell regeneration was in the decreasing order of C. grandis, G. arborea, S. pinnata reflected through the increased percentage of insulin secreting β-cells in alloxan induced diabetic rats. The extract of C. grandis produced the highest degree of β-cell regeneration demonstrated through an increase in the number of islets and percentage of the insulin secreting β-cells (75%) in the pancreas of diabetic rats (p < 0.05). Further the C. grandis extract produced a significant increase in mean profile diameter in small (118%), average (10%), and large (13%) islets as compared with diabetic control rats respectively. However, statistically significant increase in the islet profile diameter was shown only in average (2%) and large (5%) islets in the G. arborea extract treated rats and large islets (5%) in S. pinnata extract treated diabetic rats (p < 0.05). The β-cell regeneration potency was in the decreasing order of C. grandis (0.75 g/kg), G. arborea (1.00 g/kg) and S. pinnata (1.00 g/kg) in alloxan induced diabetic rats. The three plant extracts may be useful as natural agents of triggering the β-cell regeneration in the management of type 1 diabetes mellitus.

Keywords: alloxan-induced diabetic rats, β-cell regeneration, histopathology, immunohistochemistry

Procedia PDF Downloads 236

Authors: Kairat Uteulin, Azhar Iskakova, Serik Mukhambetzhanov, Bayan Yesbolayeva, Gabit Bari, Aslan Zheksenbai, Kabyl Zhambakin, Chingis Dzhabykbayev, Vladimir Piven, Izbasar Rakhimbaiev

Abstract:

To explore the potential for in vitro rapid regeneration of Russian dandelion (Taraxacum kok-saghyz Rodin), different concentrations of 6-Benzylaminopurine (BAP), 2,4-Dichlorophenoxyacetic acid (2.4-D) and BAP combined with Indole-3-acetic acid (IAA) were evaluated for their effects on the induction of somatic embryos from leaf, seed stem and root explants. Different explants were cultured on MS medium supplemented with various concentrations (0, 0.5, 1, 1.5, 2, 2.5 and 3 mg/l) of each kind of hormone. Callus induction percentage, fresh weight, color and texture of the callus were assessed after 14 and 28 days of culture. The optimum medium for the proliferation of embryogenic calli from leaf and root explants was MS supplemented with 2.5 mg/L BAP and 0.5 mg/L 2.4-D. Concentrations of 2.5 mg/L BAP and 1.5 mg/L IAA also had a remarkable effect on root and stem explants. The best concentration to produce callus from stem explants was 0.5 mg/L BAP and 1 mg/L IAA. Results of mean comparison showed that BAP and 2.4-D were more effective on different explants than BAP and IAA. Results of the double staining method proved that somatic embryogenesis occurred in the most concentrations of BAP and 2.4-D. Under microscopic observations, the different developmental stages of the embryos (globular, heart, torpedo and cotyledonary) were revealed together in callus cells, indicating that the most tested hormone combinations were effective for somatic embryogenesis formation in this species. Seed explants formed torpedo and cotyledonary stages faster than leaf and root explants in the most combinations. Most calli from seed explants were cream colored and friable, while calli were compact and light green from leaf and root explants. Some combinations gave direct regeneration and (3 mg/L BAP and 2 mg/L IAA) in seed explants and (0.5 mg/L BAP and 2.5 mg/L IAA) in leaf explants had the highest number of shoots with average of 21 and 27 shoots per callus. The developed protocol established the production of different callus types from seed, leaf, and root explants and plant regeneration through somatic embryogenesis.

Keywords: taraxacum kok-saghyz Rodin, callus, somatic embryogenesis

Procedia PDF Downloads 366

Authors: Cassandra Springate, Alexandra Furber, Jack E. Hines

Abstract:

Objectives: To create an evidence map of the cost-utility studies available with non-small cell lung cancer patients, and identify the geographical settings and interventions used. Methods: Using the Disease, Study Type, and Model Type filters in heoro.com we identified all cost-utility studies published between 1960 and 2017 with patients with non-small cell lung cancer. These papers were then indexed according to pre-specified categories. Results: Heoro.com identified 89 independent publications, published between 1995 and 2017. Of the 89 papers, 74 were published since 2010, 28 were from the USA, and 35 were from Europe, 16 of which were from the UK. Other publications were from China and Japan (13), Canada (9), Australia and New Zealand (4), and other countries (8). Fifty-nine studies included a chemotherapy intervention, of which 23 included erlotinib or gefitinib, 21 included pemetrexed or docetaxel, others included nivolumab (3), pembrolizumab (2), crizotinib (2), denosumab (2), necitumumab (1), and bevacizumab (1). Also, 19 studies modeled screening, staging, or surveillance strategies. Conclusions: The cost-utility studies found for NSCLC most commonly looked at the effectiveness of different chemotherapy treatments, with some also evaluating the addition of screening strategies. Most were also conducted with patient data from the USA and Europe.

Keywords: cancer, cost-utility, economic model, non-small cell lung cancer

Procedia PDF Downloads 147

Authors: Xian-Peng Jiang, Catherine C. Baucom, Toby Jiang, Robert L. Elliott

Abstract:

HLA-G binds to the inhibitory receptors of uterine NK cells and plays an important role in protection of fetal cells from maternal NK lysis. HLA-G also mediates tumor escape, but the immunosuppressive role is often neglected. These studies have focused on the examination of HLA-G expression in human breast carcinoma and HLA-G immunosuppressive role in NK cytolysis. We examined HLA-G expression in breast cell lines by real time PCR, ELISA and immunofluorescent staining. We treated the breast cancer cell lines with anti-human HLA-G antibody or progesterone. Then, NK cytolysis was measured by using MTT assay. We find that breast carcinoma cell lines increase the expression of HLA-G mRNA and protein, compared to normal cells. Blocking HLA-G of the breast cancer cells by the antibody increases NK cytolysis. Progesterone upregulates HLA-G mRNA and protein of human breast cancer cell lines. The increased HLA-G expression suppresses NK cytolysis. In summary, human breast carcinoma overexpress HLA-G immunosuppressive molecules. Blocking HLA-G protein by antibody improves NK cytolysis. In contrast, upregulation of HLA-G expression by progesterone impairs NK cytolytic function. Thus, HLA-G is a new immunosuppressive checkpoint and potential cancer immunotherapeutic target.

Keywords: HLA-G, Breast carcinoma, NK cells, Immunosuppressive checkpoint

Procedia PDF Downloads 81

Authors: Xijun Yu, Zhenzhen Li, Zupeng Jia

Abstract:

This paper presents a new cell-centered Lagrangian scheme for two-dimensional compressible flow. The new scheme uses a semi-Lagrangian form of the Euler equations. The system of equations is discretized by Discontinuous Galerkin (DG) method using the Taylor basis in Eulerian space. The vertex velocities and the numerical fluxes through the cell interfaces are computed consistently by a nodal solver. The mesh moves with the fluid flow. The time marching is implemented by a class of the Runge-Kutta (RK) methods. A WENO reconstruction is used as a limiter for the RKDG method. The scheme is conservative for the mass, momentum and total energy. The scheme maintains second-order accuracy and has free parameters. Results of some numerical tests are presented to demonstrate the accuracy and the robustness of the scheme.

Keywords: cell-centered Lagrangian scheme, compressible Euler equations, RKDG method

Procedia PDF Downloads 541

Authors: P. Shrivastava, S. Vijayalakshmi, A. K. Singh, S. Dalai, R. Teotia, P. Sharma, J. Bellare

Abstract:

This paper focuses on the synthesis and application of nanobioactive glass for bone regeneration studies. Nanobioactive glass has been synthesized by sol gel method having a combination of silicon, calcium and phosphorous in the molar ratio of 75:21:4. The prepared particles were analyzed for surface morphology by FEG SEM and FEG TEM. Physiochemical properties were investigated using ICP AES, FTIR spectroscopy and X-ray diffraction (XRD) techniques. To ascertain their use for therapeutic use, biocompatibility evaluation of the particles was done by performing soaking studies in SBF and in vitro cell culture studies on MG63 cell lines. Cell morphology was observed by FE SEM and phase contrast microscopy. Nanobioactive glasses (NBG) thus prepared were of 30-200 nm in size, which makes them suitable for nano-biomedical applications. The spherical shape of the particles imparts high surface to volume ratio, promoting fast growth of hydroxyapatite (HA), which is the mineral component of bone. As evaluated by in vitro cell culture studies the NBG was found to enhance the surface activation which enhances osteoblast adhesion. This is an essential parameter to improve bone tissue integration, thereby making nanobioactive glass therapeutically suitable for correcting bone defects.

Keywords: biocompatibility, bone tissue engineering, hydroxyapatite, nanobioactive glass

Procedia PDF Downloads 453

Authors: Vandana Singh, Subash Singh

Abstract:

Introduction: Oral squamous cell carcinoma is the most common malignant tumor of the oral cavity. Normally the death of cell and the growth are active processes and depend not only on external factors but also on the expression of genes like Bcl-2, which activate and inhibit apoptosis. The term Bcl-2 is an acronym for B-cell lymphoma/ leukemia -2 genes. Objectives: An attempt was made to evaluate Bcl-2 oncoprotein expression in patients with oral precancer and cancer and to assess possible correlation between Bcl-2 oncoprotein expression and clinicopathological features of oral precancer and cancer. Material and Methods: This is a selective prospective clinical and immunohistochemical study. Clinicopathological examination is correlated with immunohistochemical findings. The immunolocalization of Bcl-2 protein is performed using the labeled streptavidin biotin (LSAB) method. To visualize the reaction, 3, 3-diaminobenzidine (DAB) is used. Results: Bcl-2 expression was positive in 11 [36.66 %, low Bcl-2 expression 3 (10.00 %), moderate Bcl-2 expression 7 (23.33 %), and high Bcl-2 expression 1 (3.33 %)] oral cancer cases and in 14 [87.50 %, low expression 8 (50 %), moderate expression 6 (37.50 %)] precancer cases. Conclusion: On the basis of the results of our study we conclude that positive Bcl-2 expression may be an indicator of poor prognosis in oral cancer and precancer. Relevance: It has been reported that there is deregulation of Bcl-2 expression during progression from oral epithelial dysplasia to squamous cell carcinoma. It can be used for revealing progression of epithelial dysplasia to malignancy and as a prognostic marker in oral precancer and cancer.

Keywords: BcL-2, immunohistochemistry, oral cancer, oral precancer

Procedia PDF Downloads 255

Authors: Junichi Hosoi

Abstract:

Epidermal Langerhans cells reside in upper layer of epidermis and play a role in immune surveillance. The finding of the close association of nerve endings to Langerhans cells triggered the research on systemic regulation of Langerhans cells. They disappear from epidermis after exposure to environmental and internal stimuli and reappear about a week later. Myeloid progenitor cells are assumed to be one of the sources of Langerhans cells. We examined the effects of cortisol on the reappearance of Langerhans cells in vitro. Cord-blood derived CD34-positive cells were cultured in the medium supplemented with stem cell factor/Flt3 ligand/granulocyte macrophage-colony stimulating factor/tumor necrosis factor alpha/bone morphologic protein 7/transforming growth factor beta in the presence or absence of cortisol. Cells were analyzed by flow cytometry for CD1a (cluster differentiation 1a), a marker of Langerhans cells and dermal dendritic cells, and CD39 (cluster differentiation factor 39), extracellular adenosine triphosphatase. Both CD1a-positive cells and CD39-positive cells were decreased by treatment with cortisol (suppression by 35% and 22% compared to no stress hormone, respectively). Differentiated Langerhans cells are attracted to epidermis by chemokines that are secreted from keratinocytes. Epidermal keratinocytes were cultured in the presence or absence of cortisol and analyzed for the expression of CCL2 (C-C motif chemokine ligand 2) and CCL20 (C-C motif chemokine ligand 20), which are typical attractants of Langerhans cells, by quantitative reverse transcriptase polymerase chain reaction. The expression of both chemokines, CCL2 and CCL20, were suppressed by treatment with cortisol (suppression by 38% and 48% compared to no stress hormone, respectively). We examined the possible regulation of the suppression by cortisol with plant extracts. The extracts of Ganoderma lucidum and Iris protected the suppression of the differentiation to CD39-positive cells and also the suppression of the gene expression of LC-chemoattractants. These results suggest that cortisol, which is either systemic or locally produced, blocks the supply of epidermal Langerhans cells at 2 steps, differentiation from the precursor and attraction to epidermis. The suppression is possibly blocked by some plant extracts.

Keywords: Langerhans cell, stress, CD39, chemokine

Procedia PDF Downloads 173

Authors: Mitesh Rathod, Jungho Ahn, Noo Li Jeon, Junghoon Lee

Abstract:

Endothelial cells respond to cues from both biochemical as well as micro mechanical environment. Significant effort has been directed to understand the effects of biochemical signaling, however, relatively little is known about regulation of endothelial cell biology by the micro mechanical environment. Numerous studies have been performed to understand how physical forces regulate endothelial cell behavior. In this regard, past studies have majorly focused on exploring how fluid shear stress governs endothelial cell behavior. Parallel plate flow chambers and rectangular microchannels are routinely employed for applying fluid shear force on endothelial cells. However, these studies fall short in mimicking the in vivo like micro environment from topological aspects. Few studies have only used circular microchannels to replicate in vivo like condition. Seldom efforts have been directed to elucidate the combined effect of topology, substrate rigidity and fluid shear stress on endothelial cell response. In this regard, we demonstrate a facile fabrication process to develop a hybrid polydimethylsiloxane microfluidic platform to study endothelial cell biology. On a single chip microchannels with different cross sections i.e., circular, rectangular and square have been fabricated. In addition, our fabrication approach allows variation in the substrate rigidity along the channel length. Two different variants of polydimethylsiloxane, namely Sylgard 184 and Sylgard 527, were utilized to achieve the variation in rigidity. Moreover, our approach also enables in creating Y bifurcation circular microchannels. Our microfluidic platform thus facilitates for conducting studies pertaining to endothelial cell morphology with respect to change in topology, substrate rigidity and fluid flow on a single chip. The hybrid platform was tested by culturing Human Umbilical Vein Endothelial Cells in circular microchannels with varying substrate rigidity, and exposed to fluid shear stress of 12 dynes/cm² and static conditions. Results indicate the cell area response to flow induced shear stress was governed by the underlying substrate mechanics.

Keywords: hybrid, microfluidic platform, PDMS, shear flow, substrate rigidity

Procedia PDF Downloads 267

Authors: Kai Pei Huang, Ting Chung Hung, Li Ching Wu

Abstract:

Amyloidosis refers to a variety of conditions wherein amyloid proteins are abnormally deposited in organ or tissues and cause harm. Among the several forms of amyloidosis, the principal types of that in inpatient medical services are the AL amyloidosis (primary) and AA amyloidois (secondary). AL Amyloidois is due to deposition of protein derived from overproduction of immunoglobulin light chain in plasma cell myeloma. Furthermore, it is a systemic disorder that can present with a variety of symptoms, including heavy proteinemia and edema, heptosplenomegaly, otherwise unexplained heart failure. We reported a 78-year-old female presenting dysuria, oliguria and leg edema for several months. Laboratory data showed proteinuria (UPCR:1679.8), leukocytosis (WBC:16.2 x 10^3/uL), results of serum urea nitrogen (39mg/dL), creatinine (0.76 mg/dL), IgG (748 mg/dL.), IgA (635 mg/dL), IgM (63 mg/dL), kappa light chain(18.8 mg/dL), lambda light chain (110.0 mg/dL) and kappa/lambda ratio (0.17). Renal biopsy found amyloid fibrils in glomerular mesangial area, and Congo red stain highlights amyloid deposition in glomeruli. Additional lab studies included serum protein electrophoresis, which shows a major monoclonal peak in β region and minor small peak in gamma region, and the immunotyping studies for serum showed two IgA/λ type. We treated sample with beta-mercaptoethanol which reducing the polymerized immunoglobulin to clarify two IgA/λ are secreted from the same plasma cell clone in bone marrow. Later examination confirmed it existed plasma cell infiltration in bone marrow, and the immunohistochemical staining showed monotypic for λ light chain and are positive for IgA. All findings mentioned above reveal it is a case of plasma cell myeloma with λ Light Chain Amyloidosis.

Keywords: amyloidosis, immunoglobulin light chain, plasma cell myeloma, serum protein electrophoresis

Procedia PDF Downloads 207

Authors: Richard Harrison

Abstract:

Developing competency in mathematics and related critical thinking skills is essential to the education of undergraduate students of Science, Technology, Engineering and Mathematics (STEM). Recently, the HE sector has been impacted by a seemingly widening disconnect between the mathematical competency of incoming first-year STEM students and their entrance qualification tariffs. Despite relatively high grades in A-Level Mathematics, students may initially lack fundamental skills in key areas such as algebraic manipulation and have limited capacity to apply problem solving strategies. Compounded by compensatory measures applied to entrance qualifications during the pandemic, there has been an associated decline in student performance on introductory university mathematics modules. In the UK, a number of online resources have been developed to help scaffold the transition to university mathematics. However, in general, these do not offer a structured learning journey focused on individual developmental needs, nor do they offer an experience coherent with the teaching and learning characteristics of the destination institution. In order to address some of these issues, a bespoke framework has been designed and implemented on our VLE in the Faculty of Engineering & Physical Sciences (FEPS) at the University of Surrey. Called the FEPS Maths Support Framework, it was conceived to scaffold the mathematical development of individuals prior to entering the university and during the early stages of their transition to undergraduate studies. More than 90% of our incoming STEM students voluntarily participate in the process. Students complete a set of initial diagnostic questions in the late summer. Based on their performance and feedback on these questions, they are subsequently guided to self-select specific mathematical topic areas for review using our proprietary resources. This further assists students in preparing for discipline related diagnostic tests. The framework helps to identify students who are mathematically weak and facilitates early intervention to support students according to their specific developmental needs. This paper presents a summary of results from a rich data set captured from the framework over a 3-year period. Quantitative data provides evidence that students have engaged and developed during the process. This is further supported by process evaluation feedback from the students. Ranked performance data associated with seven key mathematical topic areas and eight engineering and science discipline areas reveals interesting patterns which can be used to identify more generic relative capabilities of the discipline area cohorts. In turn, this facilitates evidence based management of the mathematical development of the new cohort, informing any associated adjustments to teaching and learning at a more holistic level. Evidence is presented establishing our framework as an effective early intervention strategy for addressing the sector-wide issue of supporting the mathematical development of STEM students transitioning to HE

Keywords: competency, development, intervention, scaffolding

Procedia PDF Downloads 58

Authors: Tuba Kizilirmak

Abstract:

Distinct properties of porous metamaterials have been largely processed for biomedicine requiring a three-dimensional (3D) porous structure engaged with fine mechanical features, biodegradation ability, and biocompatibility. Applications of metamaterials are (i) porous orthopedic and dental implants; (ii) in vitro cell culture of metamaterials and bone regeneration of metamaterials in vivo; (iii) macro-, micro, and nano-level porous metamaterials for sensors, diagnosis, and drug delivery. There are some specific properties to design metamaterials for tissue engineering. These are surface to volume ratio, pore size, and interconnection degrees are selected to control cell behavior and bone ingrowth. In this study, additive manufacturing technique selective laser melting will be used to print the scaffolds. Selective Laser Melting prints the 3D components according to designed 3D CAD models and manufactured materials, adding layers progressively by layer. This study aims to design metamaterials with Ti6Al4V material, which gives benefit in respect of mechanical and biological properties. Ti6Al4V scaffolds will support cell attachment by conferring a suitable area for cell adhesion. This study will control the osteoblast cell attachment on Ti6Al4V scaffolds after the determination of optimum stiffness and other mechanical properties which are close to mechanical properties of bone. Before we produce the samples, we will use a modeling technique to simulate the mechanical behavior of samples. These samples include different lattice models with varying amounts of porosity and density.

Keywords: additive manufacturing, titanium lattices, metamaterials, porous metals

Procedia PDF Downloads 190

Authors: Sibele A. F. Leite, Bernno S. Leite, José Vicente H. D´Angelo, Ana Teresa P. Dell’Isola, Julio CéSar Souza

Abstract:

The generation of bioenergy is one of the oldest and simplest biomass applications and is one of the safest options for minimizing emissions of greenhouse gasses and replace the use of fossil fuels. In addition, the increasing development of technologies for energy biomass conversion parallel to the advancement of research in biotechnology and engineering has enabled new opportunities for exploitation of biomass. Agricultural residues offer great potential for energy use, and Brazil is in a prominent position in the production and export of agricultural products such as banana and rice. Despite the economic importance of the growth prospects of these activities and the increasing of the agricultural waste, they are rarely explored for energy and production of new materials. Brazil products almost 10.5 million tons/year of rice husk and 26.8 million tons/year of banana stem. Thereby, the aim of this study was to analysis the potential of biomass residues for energy production and applications in new materials. Rice husk (specify the type) and banana stem (specify the type) were characterized by physicochemical analyses using the following parameters: organic carbon, nitrogen (NTK), proximate analyses, FT-IR spectroscopy, thermogravimetric analyses (TG), calorific values and silica content. Rice husk and banana stem presented attractive superior calorific (from 11.5 to 13.7MJ/kg), and they may be compared to vegetal coal (21.25 MJ/kg). These results are due to the high organic matter content. According to the proximate analysis, biomass has high carbon content (fixed and volatile) and low moisture and ash content. In addition, data obtained by Walkley–Black method point out that most of the carbon present in the rice husk (50.5 wt%) and in banana stalk (35.5 wt%) should be understood as organic carbon (readily oxidizable). Organic matter was also detected by Kjeldahl method which gives the values of nitrogen (especially on the organic form) for both residues: 3.8 and 4.7 g/kg of rice husk and banana stem respectively. TG and DSC analyses support the previous results, as they can provide information about the thermal stability of the samples allowing a correlation between thermal behavior and chemical composition. According to the thermogravimetric curves, there were two main stages of mass-losses. The first and smaller one occurred below 100 °C, which was suitable for water losses and the second event occurred between 200 and 500 °C which indicates decomposition of the organic matter. At this broad peak, the main loss was between 250-350 °C, and it is because of sugar decomposition (components readily oxidizable). Above 350 °C, mass loss of the biomass may be associated with lignin decomposition. Spectroscopic characterization just provided qualitative information about the organic matter, but spectra have shown absorption bands around 1030 cm-1 which may be identified as species containing silicon. This result is expected for the rice husk and deserves further investigation to the stalk of banana, as it can bring a different perspective for this biomass residue.

Keywords: rice husk, banana stem, bioenergy, renewable feedstock

Procedia PDF Downloads 273

Authors: Ponchang Apollos Wuyep, Alice Njolke Mafe, Longchi Satkat Zacheaus, Dogun Ojochogu, Dabot Ayuba Yakubu

Abstract:

Fungi causes huge losses when infections occur both in plants and animals. Synthetic Antifungal drugs are mostly very expensive and highly cytotoxic when taken. This study was aimed at determining the in vitro and in vivo antifungal activities of the leaves and stem extracts of Terminalia mantaly (Umbrella tree)H. Perrier on Aspergillus species in a bid to identify potential sources of cheap starting materials for the synthesis of new drugs to address the growing antimicrobial resistance. T. mantaly leave and stem powdered plant was extracted by fractionation using the method of solvent partition co-efficient in their graded form in the order n-hexane, Ethyl acetate, methanol and distilled water and phytochemical screening of each fraction revealed the presence of alkaloids, saponins, Tannins, flavonoids, carbohydrates, steroids, anthraquinones, cardiac glycosides and terpenoids in varying degrees. The Agar well diffusion technique was used to screen for antifungal activity of the fractions on clinical isolates of Aspergillus species (Aspergillus flavus and Aspergillus fumigatus). Minimum inhibitory concentration (MIC50) of the most active extracts was determined by the broth dilution method. The fractions test indicated a high antifungal activity with zones of inhibition ranging from 6 to 26 mm and 8 to 30mm (leave fractions) and 10mm to 34mm and 14mm to36mm (stem fractions) on A. flavus and A. fumigatus respectively. All the fractions indicated antifungal activity in a dose response relationship at concentrations of 62.5mg/ml, 125mg/ml, 250mg/ml and 500mg/ml. Better antifungal efficacy was shown by the Ethyl acetate, Hexane and Methanol fractions in the in vitro as the most potent fraction with MIC ranging from 62.5 to 125mg/ml. There was no statistically significant difference (P>0.05) in the potency of the Eight fractions from leave and stem (Hexane, Ethyl acetate, methanol and distilled water, antifungal (fluconazole), which served as positive control and 10% DMSO(Dimethyl Sulfoxide)which served as negative control. In the in vivo investigations, the ingestion technique was used for the infectious studies Female Drosophilla melanogaster(UAS-Diptericin)normal flies(positive control),infected and not treated flies (negative control) and infected flies with A. fumigatus and placed on normal diet, diet containing fractions(MSM and HSM each at concentrations of 10mg/ml 20mg/ml, 30mg/ml, 40mg/ml, 50mg/ml, 60mg/ml, 70mg/ml, 80mg/ml, 90mg/ml and 100mg/ml), diet containing control drugs(fluconazole as positive control)and infected flies on normal diet(negative control), the flies were observed for fifteen(15) days. Then the total mortality of flies was recorded each day. The results of the study reveals that the flies were susceptible to infection with A. fumigatus and responded to treatment with more effectiveness at 50mg/ml, 60mg/ml and 70mg/ml for both the Methanol and Hexane stem fractions. Therefore, the Methanol and Hexane stem fractions of T. mantaly contain therapeutically useful compounds, justifying the traditional use of this plant for the treatment of fungal infections.

Keywords: Terminalia mantaly, Aspergillus fumigatus, cytotoxic, Drosophila melanogaster, antifungal

Procedia PDF Downloads 75

Authors: Chaiwat Boonkaewwan, Anutian Suklek, Jatuporn Rattanasrisomporn, Autchara Kayan

Abstract:

Toll-like receptors (TLR) are conserved microbial sensing receptors located on cell surface that are able to detect different pathogens. The aim of the present study is to examine the expression of TLR gene in peripheral blood mononuclear cell of Betong (KU line) chicken. Blood samples were collected from healthy 12 Betong (KU line) chicken. PBMCs were isolated and maintained in RPMI1640 with 10% FBS, penicillin and streptomycin. Cell viability was determined by trypan blue dye exclusion test. The expression of TLRs gene was investigated by polymerase chain reaction (PCR) technique. Results showed that PBMCs viability from Betong (KU line) chicken was 95.38 ± 1.06%. From the study of TLRs gene expression, results indicated that there are expressions of TLR1.1 TLR1.2 TLR2.1 TLR2.2 TLR3 TLR4 TLR5 TLR 7 TLR15 and TLR21 in PBMCs of Betong (KU line) chicken. In conclusion, PBMCs isolated from blood of Betong (KU line) chicken had a high cell viability ( > 95%). The expression of TLRs in chicken was all found in PBMCs, which indicated that PBMC isolated from the blood of Betong (KU line) chicken can be used as an in vitro immune responses study.

Keywords: toll-like receptor, Betong (KU line) chicken, peripheral blood mononuclear cells

Procedia PDF Downloads 219

Authors: Tim Giesen, Raphael Adamietz, Pablo Mayer, Philipp Stiefel, Patrick Alle, Dirk Schlenker

Abstract:

The competitiveness and success of new electrical energy storages such as battery cells are significantly dependent on a short time-to-market. Producers who decide to supply new battery cells to the market need to be easily adaptable in manufacturing with respect to the early customers’ needs in terms of cell size, materials, delivery time and quantity. In the initial state, the required output rates do not yet allow the producers to have a fully automated manufacturing line nor to supply handmade battery cells. Yet there was no solution for manufacturing battery cells in low to medium volumes in a reproducible way. Thus, in terms of cell format and output quantity, a concept for the flexible assembly of battery cells was developed by the Fraunhofer-Institute for Manufacturing Engineering and Automation. Based on clustered processes, the modular system platform can be modified, enlarged or retrofitted in a short time frame according to the ordered product. The paper shows the analysis of the production steps from a conventional battery cell assembly line. Process solutions were found by using I/O-analysis, functional structures, and morphological boxes. The identified elementary functions were subsequently clustered by functional coherences for automation solutions and thus the single process cluster was generated. The result presented in this paper enables to manufacture different cell products on the same production system using seven process clusters. The paper shows the solution for a batch-wise flexible battery cell production using advanced process control. Further, the performed tests and benefits by using the process clusters as cyber-physical systems for an integrated production and value chain are discussed. The solution lowers the hurdles for SMEs to launch innovative cell products on the global market.

Keywords: automation, battery production, carrier, advanced process control, cyber-physical system

Procedia PDF Downloads 326

Authors: Nehir Nebioglu

Abstract:

Chemotherapy is widely used for the treatment of cancer. Doxorubicin is an anti-cancer chemotherapy drug that is classified as an anthracycline antibiotic. Antitumor antibiotics consist of natural products produced by species of the soil fungus Streptomyces. These drugs act in multiple phases of the cell cycle and are known cell-cycle specific. Although DOX is a precious clinical antineoplastic agent, resistance is also a problem that limits its utility besides cardiotoxicity problem. The drug resistance of cancer cells results from multiple factors including individual variation, genetic heterogeneity within a tumor, and cellular evolution. The mechanism of resistance is thought to involve, in particular, ABCB1 (MDR1, Pgp) and ABCC1 (MRP1) as well as other transporters. Several studies on DOX-resistant cell lines have shown that resistance can be overcome by an inhibition of ABCB1, ABCC1, and ABCC2. This study attempts to understand the effects of different concentration levels of glucose treatment and starvation on the proliferation of Doxorubicin resistant cancer cells lines. To understand the effect of starvation, K562/Dox and K562 cell lines were treated with 0, 5 nM, 50 nM, 500 nM, 5 uM and 50 uM Dox concentrations in both starvation and normal medium conditions. In addition to this, to interpret the effect of glucose treatment, different concentrations (0, 1 mM, 5 mM, 25 mM) of glucose were applied to Dox-treated (with 0, 5 nM, 50 nM, 500 nM, 5 uM and 50 uM) K562/Dox and K652 cell lines. All results show significant decreasing in the cell count of K562/Dox, when cells were starved. However, while proliferation of K562/Dox lines decrease is associated with the increasingly applied Dox concentration, K562/Dox starved ones remain at the same proliferation level. Thus, the results imply that an amount of K562/Dox lines gain starvation resistance and remain resistant. Furthermore, for K562/Dox, there is no clear effect of glucose treatment in terms of cell proliferation. In the presence of a moderate level of glucose (5 mM), proliferation increases compared to other concentration of glucose for each different Dox application. On the other hand, a significant increase in cell proliferation in moderate level of glucose is only observed in 5 uM Dox concentration. The moderate concentration level of Dox can be examined in further studies. For the high amount of glucose (25 mM), cell proliferation levels are lower than moderate glucose application. The reason could be high amount of glucose may not be absorbable by cells. Also, in the presence of low amount of glucose, proliferation is decreasing in an orderly manner of increase in Dox concentration. This situation can be explained by the glucose depletion -Warburg effect- in the literature.

Keywords: drug resistance, cancer cells, chemotherapy, doxorubicin

Procedia PDF Downloads 171

Authors: Augustine O. Ani, Ifeyinwa E. Ezemagu, Eunice A. Akuru

Abstract:

A seven-week study was conducted to evaluate the response of grower turkeys to varying dietary levels of Moringa oleifera leaf meal (MOLM) in a humid tropical environment. A total of 90 twelve weeks old male and female grower turkeys were randomly divided into five groups of 18 birds each in a completely randomized design (CRD) and assigned to five caloric (2.57-2.60 Mcal/kg ME) and isonitrogenous (19.95% crude protein) diets containing five levels (0, 15, 20, 25 and 30%) of MOLM, respectively. Each treatment was replicated three times with 6 birds per replicate housed in a deep litter pen of fresh wood shavings measuring 1.50m x 1.50m. Feed and water were provided to the birds' ad libitum. Parameters measured were: final live weight (FLW) daily weight gain (DWG), daily feed intake (DFI), feed conversion ratio (FCR), protein efficiency ratio (PER), packed cell volume (PCV), haemoglobin concentration (Hb), red blood cell (RBC) count, white blood cell (WBC) count, mean cell volume (MCV), mean cell haemoglobin (MCH) and mean cell haemoglobin concentration (MCHC), feed cost / kg weight gain and apparent nutrient retention. Results showed that grower turkeys fed 20% MOLM diet had significantly (p < 0.05) higher FLW and DWG values (4410.30 g and 34.49 g, respectively) and higher DM and NFE retention values (67.28 and 58.12%, respectively) than turkeys fed other MOLM diets. Feed cost per kg gain decreased significantly (p < 0.05) with increasing levels of MOLM in the diets. The PCV, Hb, WBC, MCV, MCH and MCHC values of grower turkeys fed 20% MOLM diet were significantly (p < 0.05) higher than those of grower turkeys fed other diets. It was concluded that a diet containing 20% MOLM is adequate for the normal growth of grower turkeys in the tropics.

Keywords: Diets, grower turkeys, Moringa oleifera leaf meal, response, tropical environment

Procedia PDF Downloads 138

Authors: Yosika Dian Komala, Uke Kurniawan Usman, Yuyun Siti Rohmah

Abstract:

The enable technology fills up needs of high-speed data service is Universal Mobile Telecommunications Service (UMTS). UMTS has a data rate up to 2Mbps.UMTS terrestrial system has a coverage area about 1-2km. High Altitude Platform Station (HAPS) can be built by a macro cell that is able to serve the wider area. Design method of UMTS using HAPS is planning base on coverage and capacity. The planning method is simulated with 2.8.1 Atoll’s software. Determination of radius of the cell based on the coverage uses free space loss propagation model. While the capacity planning to determine the average cell through put is available with the Offered Bit Quantity (OBQ).

Keywords: UMTS, HAPS, coverage planning, capacity planning, signal level, Ec/Io, overlapping zone, throughput

Procedia PDF Downloads 631

Authors: Anthara Vivek, Manisha Shukla, Mahesh Narayan, Prakash Narayan

Abstract:

Sickle cell disease disproportionately affects sub-Saharan Africa and certain tribal populaces in India and has consequently drawn little intertest from Pharma. In sickle cell patients, adhesion of erythrocytes or reticulocytes to one another and the vessel wall results in painful ischemic episodes with few, if any, effective treatments for vaso-occlusive crises. Identification of disease-associated adhesion markers on erythrocytes or reticulocytes might inform the use of more effective therapies against vaso-occlusive crises. Increased expression of one or more of bcam, itga4, cd44, cd47, rap1a, vcam1, or icam4 has been reported in sickle cell subjects. Using the miRNet ontology knowledgebase, peripheral blood interactomes were generated by seeding various combinations of the afore-referenced mRNA. These interactomes yielded an array of miR targets. As examples, targeting hsa-miR-155-5p can potentially neutralize the rap1a-bcam-cd44-itga4-vcam1 erythrocyte/reticulocyte adhesion interactome whereas targeting hsa-miRs-103a-3p or 107 can potentially neutralize adhesion in cells overexpressing icam4-cd47-bcam-itga4-cd36. AM3380 (MIRacle™) is an off-the shelf hsa-miR-155-5p agomiR that can potentially neutralize the rap1a-bcam-cd44-itga4-vcam1 signaling axis. Phlebotomy coupled with transcriptomics represents a potentially feasible and effective precision medicine strategy to mitigate vaso-occlusive crises in sickle cell patients.

Keywords: adhesion, interactome, precision, medicine

Procedia PDF Downloads 67

Authors: Weili Shao, Qian Wang, Jianxin He

Abstract:

Recently, the applications of graphene oxide in fabricating scaffolds for bone tissue engineering have been received extensive concern. In this work, poly l-lactic/graphene oxide composite nanofibers were successfully fabricated by electrospinning. The morphology structure, porosity and mechanical properties of the composite nanofibers were characterized using different techniques. And mouse mesenchymal stem cells were cultured on the composite nanofiber scaffolds to assess their suitability for bone tissue engineering. The results indicated that the composite nanofiber scaffolds had finer fiber diameter and higher porosity as compared with pure poly l-lactic nanofibers. Furthermore, incorporation of graphene oxide into the poly l-lactic nanofibers increased protein adsorptivity, boosted the Young’s modulus and tensile strength by nearly 4.2-fold and 3.5-fold, respectively, and significantly enhanced adhesion, proliferation, and osteogenesis in mouse mesenchymal stem cells. The results indicate that composite nanofibers could be excellent and versatile scaffolds for bone tissue engineering.

Keywords: poly l-lactic, graphene oxide, osteogenesis, bone tissue engineering

Procedia PDF Downloads 297

Authors: Sri Rahayu, M. Dwi Susan, Aris Soewondo, W. M. Agung Pramana

Abstract:

Semen is an organic fluid (seminal plasma) that contain spermatozoa. Proteins are one of the major seminal plasma components that modulate sperm functionality, influence sperm capacitation and maintaining the stability of the membrane. Semen freezing is a procedure to preserve sperm cells. The process causes decrease in sperm viability due to temperature shock and oxidation stress. Oxidation stress is a disturbance on phosphorylation that increases ROS concentration, and it produces lipid peroxide in spermatozoa membrane resulted in high MDA (malondialdehyde) concentration. The objective of this study was to examine the effect of freezing on protein and MDA profile of bovine sperm cell and seminal plasma after freezing. Protein and MDA of sperm cell and seminal plasma were isolated from 10 sample. Protein profiles was analyzed by SDS PAGE with separating gel 12,5 %. The concentration of MDA was measured by spectrophotometer. The results of the research indicated that freezing of semen cause lost of the seminal plasma proteins with molecular with 20, 10, and 9 kDa. In addition, the result research showed that protein of the sperm (26, 10, 9, 7, and 6 kDa) had been lost. There were difference MDA concentration of seminal plasma and sperm cell were increase after freezing. MDA concentration of seminal plasma before and after freezing were 2.2 and 2.4 nmol, respectively. MDA concentration of sperm cell before and after freezing were 1,5 and 1.8 nmol, respectively. In conclusion, there were differences protein profiles of spermatozoa before and after semen freezing and freezing cause increasing of the MDA concentration.

Keywords: MDA, semen freezing, SDS PAGE, protein profile

Procedia PDF Downloads 269

Authors: Svitlana Antonenko, Gennady Telegeev

Abstract:

Introductive statement: The development of chronic myeloid leukemia (CML) is caused by Bcr-Abl oncoprotein. Modern treatments with tyrosine kinase inhibitors are greatly complicated by the mutational variability of the Bcr-Abl oncoprotein, which causes drug resistance. Therefore, there is an urgent need to develop new approaches to the treatment of the disease, which will allow modeling the level of Bcr-Abl oncoprotein in the cell. Promising in this direction is the identification of proteases that can selectively promote cellular proteolysis of oncoproteins. The aim of the study was to study the effect of the interaction of Bcr-Abl with deubiquitinase USP1 on the level of oncoprotein in CML cells. Methodology: K562 cells were selected for the experiment. Сells were incubated with ML323 inhibitor for 24 hours. Precipitation of endogenous proteins from K562 cell lysate was performed using anti-Bcr-Abl antibodies. Cell lysates and precipitation results were studied by Western blot. Subcellular localization of proteins was studied by immunofluorescence analysis followed by confocal microscopy. The results were analyzed quantitatively and statistically. Major findings: The Bcr-Abl/USP1 protein complex was detected in CML cells, and it was found that inhibition of USP1 deubiquitinating activity by the compound ML323 leads to disruption of this protein complex and a decrease in the level of Bcr-Abl oncoprotein in cells. The interaction of Bcr-Abl with USP1 may result in deubiquitination of the oncoprotein, which disrupts its proteasomal degradation and leads to the accumulation of CML in cells. Conclusion: We believe that the interaction of oncoprotein with USP1 may be one of the prerequisites that contribute to malignant cell transformation due to the deubiquitination of oncoprotein, which leads to its accumulation and disease progression. A correlation was found between the deubiquitinating activity of USP1 and the level of oncoprotein in CML cells. Thus, we identify deubiquitinase USP1 as a promising therapeutic target for the development of a new strategy for the treatment of CML by modulating the level of Bcr-Abl in the cell.

Keywords: chronic myeloid leukemia, Bcr-Abl, USP1, deubiquitination Bcr-Abl, K562 cell

Procedia PDF Downloads 63

Authors: Rabindranath Jana, Biswajit Maity, Keka Rana

Abstract:

The most promising clean energy source is the fuel cell, since it does not generate toxic gases and other hazardous compounds. Again the direct methanol fuel cell (DMFC) is more user-friendly as it is easy to be miniaturized and suited as energy source for automobiles as well as domestic applications and portable devices. And unlike the hydrogen used for some fuel cells, methanol is a liquid that is easy to store and transport in conventional tanks. The most important part of a fuel cell is its membrane. Till now, an overall efficiency for a methanol fuel cell is reported to be about 20 ~ 25%. The lower efficiency of the cell may be due to the critical factors, e.g. slow reaction kinetics at the anode and methanol crossover. The oxidation of methanol is composed of a series of successive reactions creating formaldehyde and formic acid as intermediates that contribute to slow reaction rates and decreased cell voltage. Currently, the investigation of new anode catalysts to improve oxidation reaction rates is an active area of research as it applies to the methanol fuel cell. Surprisingly, there are very limited reports on nanostructured membranes, which are rather simple to manufacture with different tuneable compositions and are expected to allow only the proton permeation but not the methanol due to their molecular sizing effects and affinity to the membrane surface. We have developed a nanostructured fuel cell membrane from polydimethyl siloxane rubber (PDMS), ethylene methyl co-acrylate (EMA) and multi-walled carbon nanotubes (MWNTs). The effect of incorporating different proportions of f-MWNTs in polymer membrane has been studied. The introduction of f-MWNTs in polymer matrix modified the polymer structure, and therefore the properties of the device. The proton conductivity, measured by an AC impedance technique using open-frame and two-electrode cell and methanol permeability of the membranes was found to be dependent on the f-MWNTs loading. The proton conductivity of the membranes increases with increase in concentration of f-MWNTs concentration due to increased content of conductive materials. Measured methanol permeabilities at 60oC were found to be dependant on loading of f-MWNTs. The methanol permeability decreased from 1.5 x 10-6 cm²/s for pure film to 0.8 x 10-7 cm²/s for a membrane containing 0.5wt % f-MWNTs. This is due to increasing proportion of f-MWNTs, the matrix becomes more compact. From DSC melting curves it is clear that the polymer matrix with f-MWNTs is thermally stable. FT-IR studies show good interaction between EMA and f-MWNTs. XRD analysis shows good crystalline behavior of the prepared membranes. Significant cost savings can be achieved when using the blended films which contain less expensive polymers.

Keywords: fuel cell membrane, polydimethyl siloxane rubber, carbon nanotubes, proton conductivity, methanol permeability

Procedia PDF Downloads 409

Authors: Ece Çetin, İsmail Boz, Mehtap Şafak Boroğlu

Abstract:

Energy is one of the most important components of production processes, economic activities, and daily life. Non-renewable energy sources cause serious environmental problems with the increase of greenhouse gases. Obtaining energy from renewable sources is also essential for sustainable economic growth. Solar energy is also an important renewable energy source with its unlimited and clean features. In this study, the effect of 1, 2, and 3 layers of perovskite film number and antisolvent dripping on perovskite based solar cell efficiency was investigated. The yield increased as the number of perovskite films increased. In addition, the yields obtained with the antisolvent dripped in the last 5 seconds are higher than the ones dropped in the last 17 seconds. The highest efficiency was obtained with 3 perovskite films, and antisolvent dropped in the last 5 seconds.

Keywords: antisolvent, efficiency, perovskite, solar cell

Procedia PDF Downloads 103

Authors: Nura Brimo, Dilek Cokeliler Serdaroglu, Tansel Uyar, Busra Uysal, Elif Bahar Cakici, Miris Dikmen, Zerrin Canturk

Abstract:

Background: A combination of antibiotics, including metronidazole (MET), ciprofloxacin (CIP), and minocycline (MINO), has been demonstrated to disinfect bacteria in necrotic teeth before regenerative processes. It has been presented clinically that antibiotic pastes may drive to possible stem cell death and difficulties in removing from the canal system, which can limit the regenerative procedure. This study was designed to (1) synthesize nanofibrous webs containing various concentrations of different medicaments (triple, double, and calcium hydroxide,Ca(OH)2), and (2) coat thiselectrospun fibrous gutta-percha (GP) cones. Methods: Poly(vinylpyrrolidone) (PVP)-based electrospun fibrous webs were processed with low medicaments concentrations. Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDX), and X-Ray Photoelectron Spectroscopy (XPS) were carried out to investigate fiber morphology, antibiotic incorporation, and characterized GP-coated fibrous webs, respectively. The chemical and physical properties of dentine were carried out via Fourier Transform Infrared Spectroscopy (FTIR) and Nano-SEM, respectively. The antimicrobial properties of the different fibrous webs were assessed against various bacteria by direct nanofiber/bacteria contact. Cytocompatibility was measured by applying the MTT method. Results: The mean fiber diameter of the experiment groups of medicament-containing fibers ranged in the nm scale and was significantly smaller than PVP fibers. EDX analysis confirmed the presence of medicaments in the nanofibers. XPS analysis presented a complete coating of the fibers with GPs; FTIR and Nano-SEM showed no chemical and physical configuration of intracanal medicaments on the dentine surface. Meanwhile, nanofibrous webs led to a significant reduction in the percentage of viable bacteria compared with the negative control and PVP. Conclusion: Our findings suggest that TA-NFs, DA-NFs, and Cₐ(OH)₂)-NFs coated GP cones have significant potential in eliminating intracanal bacteria, cell-friendly behavior, and clinical usage features.

Keywords: drug delivery, drug carrier, electrospinning, nano/microfibers, regenerative endodontic, morphology

Procedia PDF Downloads 106