Capture Purity Research Articles

Assessment of reasonable opportunities for direct air capture

This work explores the possibility of using CO2 captured directly from the atmosphere for several applications that require low to moderate purities. Comparisons of the minimum and real work for separating CO2 from air, natural gas combined cycle flue gas and pulverized coal combustion flue gas are proposed and discussed. Although it is widely accepted that the separation of CO2 from air to high purity is more energy-intensive than separating CO2 from more concentrated sources, this study presents select cases where the separation of CO2 from air to low and moderate purities is energetically equivalent with the work required for flue gas CO2 separation. These energetically-competitive cases are shown to be dependent on the percent capture and final CO2 purity desired. In particular, several technologies can be considered as CO2 utilization opportunities in which dilute CO2 may be an adequate feedstock. Specifically, this study is focused on enhanced oil recovery and microalgae cultivation technologies, which appear to be the most beneficial near-term applications for utilization of CO2 from direct air capture.

Modelling of high purity H2 production via sorption enhanced chemical looping steam reforming of methane in a packed bed reactor

Sorption enhanced chemical looping steam reforming of methane (SE-CLSR) relies on the exothermicity of both a metal catalyst’s oxidation and the in situ CO2 capture by carbonation onto a solid sorbent to provide the heat demand of hydrogen (H2) production by steam reforming while generating a nearly pure H2 product. A brief thermodynamic analysis to study the main features of the SE-CLSR process is done prior to the reactor modelling work. Later, one dimensional mathematical model of SE-CLSR process in the packed bed configuration is developed using gPROMS model builder 4.1.0® under the adiabatic conditions. This model combines reduction of the NiO catalyst with the steam reforming reactions, followed by the oxidation of the Ni-based reduced catalyst. The individual models of NiO reduction, steam reforming with in situ CO2 capture on Ca-sorbent, and Ni re-oxidation are developed by using kinetic data available in literature and validated against previous published work. The model of SE-CLSR is then applied to simulate 10 alternative cycles of the fuel and air feed in the reactor. The performance of the model is studied in terms of CH4 conversion, CO2 capture efficiency, purity and yield of H2. The sensitivity of the process is studied under the various operating conditions of temperature, pressure, molar steam to carbon ratio (S/C) and mass flux of the gas phase. In this work, the operating conditions used for the production of H2 represent realistic industrial production conditions. The sensitivity analysis demonstrates that the developed model of SE-CLSR process has the flexibility to simulate a wide range of operating conditions of temperature, pressure, S/C and mass flux of the gas phase.

Dual-Functional Lipid Coating for the Nanopillar-Based Capture of Circulating Tumor Cells with High Purity and Efficiency.

Clinical studies of circulating tumor cells (CTC) have stringent demands for high capture purity and high capture efficiency. Nanostructured surfaces have been shown to significantly increase the capture efficiency yet suffer from low capture purity. Here we introduce a dual-functional lipid coating on nanostructured surfaces. The lipid coating serves both as an effective passivation layer that helps prevent nonspecific cell adhesion and as a functionalized layer for antibody-based specific cell capture. In addition, the fluidity of lipid bilayers enables antibody clustering that enhances the cell-surface interaction for efficient cell capture. As a result, the lipid-coating method helps promote both the capture efficiency and capture purity of nanostructure-based CTC capture.

Abstract 1525: Vortex technology for label-free enrichment of CTC from mouse xenograft models

Abstract Background Non-invasive liquid biopsies, such as CTCs, have been of growing interest due to their potential use in cancer detection, prognosis, and monitoring of therapeutic resistance [1]. Beyond enumeration, characterization of CTCs could help guide treatment selection and the development of targeted cancer therapy. Here, we show that Vortex technology can be used successfully for the size-based capture of CTCs in a preclinical mouse model of breast cancer. Method To establish that human epithelial cancer cells can be reliably detected in small volumes of mice blood, 50-100 MDA-MB231 and MCF7 breast cancer cells were spiked in 500 μL mice blood, diluted 20 fold, and processed through Vortex chip [2]. Recovered cells were immunostained (CK, CD45, DAPI), and enumerated. For breast cancer xenograft model, 8×106 MDA-MB-231-fLuc/GFP cells were implanted orthotopically into the mammary fat pad of NOD-SCID Gamma mice (n = 35). Tumors were measured in 2 dimensions 3 times/week and tumor volume calculated. Blood from cardiac puncture (500 μl) and lateral saphenous vein (100 μl) was collected starting 1 week post implantation, diluted 40X and processed. Mice were euthanized, organs harvested, formalin fixed, paraffin embedded and H&E stained. Results Spiking of MCF7 cells in mouse blood resulted in a capture efficiency of 56.9±13% and a purity of 80.1± 9% (n = 3), with the flow-through from each cycle being re-processed for a total of 4 cycles. Recycling the flow-through led to capture efficiency of 36.7%, 23.4%, 5.2% and 7.9% during cycles 1, 2, 3 and 4 respectively. Similar results were obtained for MDA-MB-231, with a capture efficiency of 54.4% and a purity of 41.3%. In an orthotopic tumor xenograft model of breast cancer, CTCs were successfully recovered from cardiac puncture as early as day 7. CTC counts, ranging from 0.4-3649 CTCs/100 μl, increased over time and correlated with tumor burden. CTC clusters were also captured from day 7 (6 clusters/100 μl; frequency 1/3), with number and frequency increasing over time up to 147-485 clusters/100 μl by day 42. No CTC were recovered from lateral saphenous vein blood until day 28 post implantation, and their number remained low (mean 2.15±0.65). Microscopic metastases were evident in lung of all mice starting at day 28 and in liver of all mice starting at day 35. Conclusion CTCs were isolated in a label-free manner from mice blood with both high capture efficiency and purity. In a preclinical model of metastatic breast cancer, CTC counts correlated well with primary tumor volume and metastases occurrence. Thus the Vortex chip appears to be well suited for the enrichment of CTCs from murine xenograft models. Future works will focus on mice implanted with patient derived xenograft (PDX) and their therapeutic response. Information gathered from these studies should facilitate discovery of new therapeutic targets and the development of personalized medicine. [1] Ignatiadis et al. Clin Cancer Res 2015. [2] Sollier et al. Lab Chip 2014.[K.H. and M.T. contributed equally to this work.] Citation Format: Kyra Heirich, Melanie M. Triboulet, Corinne M. Renier, Vishnu C. Ramani, Elodie Sollier, Stefanie S. Jeffrey. Vortex technology for label-free enrichment of CTC from mouse xenograft models. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1525.

Abstract 3966: Effect of anticoagulant and sample storage conditions on circulating tumor cells enrichment by vortex

Abstract Background Circulating tumor cells (CTC) have recently emerged as powerful biomarkers for non-invasive diagnosis and prognosis of cancer [1]. The rarity and fragility of these cells has proven to be a significant impediment to their clinical use. Delay between phlebotomy and sample processing, together with blood sample storage, can impact the integrity of these cells and hamper their subsequent isolation. Addressing these issues could allow shipping between clinical facilities and significantly increase the use of CTCs. Here, we assessed the effects of various blood anticoagulants on the isolation of CTCs using Vortex technology. Vortex is a label-free, size-based technology that relies on the generation of laminar flow microvortices where CTCs can be trapped [2], and released off-chip, into a small volume compatible with various downstream assays. Methods To evaluate the effects of delayed processing on capture performances, samples from healthy donors were drawn into 4 different blood collection tubes (BCT): K3EDTA, ACD-B, CellSave and cell-free DNA Streck. Each BCT was spiked with MCF7 breast cancer cells and stored at room temperature for up to 3 days (72H). On days 0, 1, 2 and 3, aliquots of blood (0.5 ml; n = 3) from each BCT were diluted 10X and processed through Vortex chip. Captured cells were stained (CK, CD45, DAPI) and enumerated. Capture efficiency and purity were determined for each time point and BCT. To simulate over-sea shipping and processing of patient samples, larger blood volumes (6mL in EDTA, CellSave and Streck BCT) were also tested after 48H. Capture performances and device clogging were evaluated. Results Significant differences were observed for capture performances between the BCTs. Best results were obtained for CellSave tube, with an efficiency of 19.8 ± 2.5%, stable for up to 3 days, and a purity ranging from 40.6 to 52.8%. In comparison, performances for standard K3EDTA were maximal at 24H, with 19.1% efficiency decreasing to 10% at 72H. ACD-B and Streck showed lower efficiencies, reaching 4.6 and 9.7% respectively. Purity for EDTA, CellSave and Streck BCT was in a similar range (48.4, 46.5 and 34.9% respectively). No significant device clogging was observed between EDTA, CellSave and Streck BCT when larger blood volumes were processed. Conclusion Here we demonstrate the ability to isolate cancer cells spiked in blood for up to 48H post-phlebotomy, with higher overall performances obtained with CellSave tube. Standard EDTA BCT gives optimal performances up to 24H and would be the option to select whenever viable cells are required. This suggests that Vortex technology is compatible with various anticoagulants and preservatives containing blood collection tube; the election would depend on the assay performed downstream. Future work will include shipping blood samples from remote sites and effect on CTC enrichment by Vortex technology. [1] Ignatiadis et al. Clin Cancer Res 2015. [2] Sollier et al. Lab Chip 2014. Citation Format: Charles L. Wilkerson, Corinne M. Renier, Violet R. Hanft, Stefanie S. Jeffrey, Elodie Sollier. Effect of anticoagulant and sample storage conditions on circulating tumor cells enrichment by vortex. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3966.

Separation of viable and nonviable mammalian cells using a deterministic lateral displacement microfluidic device

Here, we present a deterministic lateral displacement (DLD) microfluidic device that may be used for label-free, passive, and continuous separation of viable and nonviable mammalian cells. Cells undergoing apoptosis (programmed cell death) become smaller than normal viable cells due to shrinkage and fragmentation. We used this distinct difference in size to selectively isolate viable Jurkat cells from nonviable apoptotic cells and their remnants through a DLD array that is capable of size-based fractionation of microparticles. First, we calibrated our DLD devices by separating a mixture of larger (∼15-μm) and smaller (∼8- or ∼10-μm) polystyrene beads that emulated viable and nonviable Jurkat cells, respectively. We then demonstrated the separation of viable and nonviable Jurkat cells by introducing their heterogeneous suspensions into two DLD devices with different design parameters. In a DLD device with a 20-μm gap, we collected viable cells at 100 ± 0% capture efficiency (n = 3), at a capture purity of 23.1 ± 4.8%, with 57.8 ± 8.1% removal efficiency of nonviable apoptotic cells and their remnants from the initial mixture solution. On a DLD device with a 23-μm gap, the capture purity of viable cells increased to 50.2 ± 15.0%, with 89.0 ± 3.5% removal efficiency of nonviable cells, and a lower capture efficiency of 48.2 ± 2.0% (n = 3). This first demonstration of label-free and passive separation of viable and nonviable cells by DLD illustrates its potential for, e.g., regenerative medicine and discovery of anti-cancer drugs.

Continuous enrichment of circulating tumor cells using a microfluidic lateral flow filtration chip

The isolation and characterization of circulating tumor cells (CTC) is of great importance in cancer diagnosis and prognosis. Highly sensitive detection of CTCs can be very difficult because they are extremely rare (i.e., 1-5 CTCs per 109 erythrocytes) in blood. Recently, various devices have been developed that exploit biochemical (affinity-based) and physical (size or density) methods. Antibody-based isolation has its own limitations, as the expression level of the epitopes for an antibody varies due to the heterogeneity of cancer cells. Harsh conditions associated with physical methods can cause the deformation and damage of CTCs during the isolation process. Here, we propose a microfluidic lateral flow filtration (μ-LaFF) chip in which lateral flow was combined with vertical flow into the filter to capture the CTCs gently. The CTCs experienced weak shear flow owing to the lateral flow and traveled alongside the filter channel until finally being captured. The vertical flow in the filter held the captured cells tightly and served as an exit for uncaptured hematological cells (white and red blood cells). From our μ-LaFF chip we obtained a high capture efficiency (95%) and purity (99%), minimizing any damage to the CTCs. Our μ-LaFF technology is expected to be useful in the diagnosis and prognosis of various cancers.

Nanotentacle-structured magnetic particles for efficient capture of circulating tumor cells.

Circulating tumor cells (CTCs) have attracted considerable attention as promising markers for diagnosing and monitoring the cancer status. Despite many technological advances in isolating CTCs, the capture efficiency and purity still remain challenges that limit clinical practice. Here, the construction of "nanotentacle"-structured magnetic particles using M13-bacteriophage and their application for the efficient capturing of CTCs is demonstrated. The M13-bacteriophage to magnetic particles followed by modification with PEG is conjugated, and further tethered monoclonal antibodies against the epidermal receptor 2 (HER2). The use of nanotentacle-structured magnetic particles results in a high capture purity (>45%) and efficiency (>90%), even for a smaller number of cancer cells (≈25 cells) in whole blood. Furthermore, the cancer cells captured are shown to maintain a viability of greater than 84%. The approach can be effectively used for capturing CTCs with high efficiency and purity for the diagnosis and monitoring of cancer status.

Nanotopographic Biomaterials for Isolation of Circulating Tumor Cells

Circulating tumor cells (CTCs) shed from the primary tumor mass and circulating in the bloodstream of patients are believed to be vital to understand of cancer metastasis and progression. Capture and release of CTCs for further enumeration and molecular characterization holds the key for early cancer diagnosis, prognosis and therapy evaluation. However, detection of CTCs is challenging due to their rarity, heterogeneity and the increasing demand of viable CTCs for downstream biological analysis. Nanotopographic biomaterial-based microfluidic systems are emerging as promising tools for CTC capture with improved capture efficiency, purity, throughput and retrieval of viable CTCs. This review offers a brief overview of the recent advances in this field, including CTC detection technologies based on nanotopographic biomaterials and relevant nanofabrication methods. Additionally, the possible intracellular mechanisms of the intrinsic nanotopography sensitive responses that lead to the enhanced CTC capture are explored.

Microfluidic antibody arrays for simultaneous cell separation and stimulus.

A microfluidic chip containing stamped antibody arrays was developed for simultaneous cell separation and drug testing. Poly(dimethyl siloxane) (PDMS) stamping was used to deposit antibodies in a microfluidic channel, forming discrete cell-capture regions on the surface. Cell mixtures were then introduced, resulting in the separation of cells when specific antibodies were used. Anti-CD19 antibody regions resulted in 94% capture purity for CD19+ Ramos cells. An antibody that captures multiple cell types, for example anti-CD71, can also be used to capture several cell types simultaneously. Cells could also be loaded onto the arrays with spatial control using laminar streams. Both Ramos B cells and HuT 78T cells were isolated in the chip and exposed to staurosporine in the same channel. Both cell lines had similar responses to the drug, with 2-10% of cells remaining viable after 20h of drug treatment, depending on cell type. The chip can also be used to analyze the efficacy of antibody therapy against cancer cells. Anti-CD95 was deposited on the surface and used for simultaneous cell capture and apoptosis induction via the extrinsic pathway. Cells captured on anti-CD95 surfaces had significant viability loss (15% viability after 24h) when compared with a control anti-CD71 antibody (81% viability after 24h). This chip can be used for a variety of cell separation and/or drug testing studies, enabling researchers to isolate cells and test them against different anti-cancer compounds and to follow cell response using fluorescence or other readout methods.

Characterization of microfluidic shear-dependent epithelial cell adhesion molecule immunocapture and enrichment of pancreatic cancer cells from blood cells with dielectrophoresis.

Current microfluidic techniques for isolating circulating tumor cells (CTCs) from cancer patient blood are limited by low capture purity, and dielectrophoresis (DEP) has the potential to complement existing immunocapture techniques to improve capture performance. We present a hybrid DEP and immunocapture Hele-Shaw flow cell to characterize DEP's effects on immunocapture of pancreatic cancer cells (Capan-1, PANC-1, and BxPC-3) and peripheral blood mononuclear cells (PBMCs) with an anti-EpCAM (epithelial cell adhesion molecule) antibody. By carefully specifying the applied electric field frequency, we demonstrate that pancreatic cancer cells are attracted to immunocapture surfaces by positive DEP whereas PBMCs are repelled by negative DEP. Using an exponential capture model to interpret our capture data, we show that immunocapture performance is dependent on the applied DEP force sign and magnitude, cell surface EpCAM expression level, and shear stress experienced by cells flowing in the capture device. Our work suggests that DEP can not only repel contaminating blood cells but also enhance capture of cancer cell populations that are less likely to be captured by traditional immunocapture methods. This combination of DEP and immunocapture techniques to potentially increase CTC capture purity can facilitate subsequent biological analyses of captured CTCs and research on cancer metastasis and drug therapies.

Experimental Demonstration of a Novel Gas Switching Combustion Reactor for Power Production with Integrated CO2Capture

This paper experimentally demonstrates the feasibility of a novel gas switching combustion (GSC) reactor as an alternative to the traditional chemical looping combustion (CLC) process for power production with integrated CO2 capture. Whereas the CLC process circulates an oxygen carrier material between two fluidized bed reactors, where it is exposed to separate fuel and air streams, the GSC concept employs a single dense fluidized bed reactor where the oxygen carrier is periodically exposed to fuel and air streams. A lab-scale GSC reactor was operated autothermally (without any external temperature supply) to continuously convert cold feed gases into hot product gases, which would be suitable for driving a downstream power cycle. A parametric study was carried out to further investigate the behavior of the GSC concept. The reactor achieved a high CO2 capture efficiency (97.2%) and purity (98.2%) even without the use of a purging stage between the oxidation and reduction stages. A small amount of carbon deposition (around 1%) had a slight negative effect on the CO2 capture efficiency. Finally, the operation of a cluster of GSC reactors capable of delivering two steady process streams to downstream process equipment is discussed.

P38 signaling and receptor recycling events in a microfluidic endothelial cell adhesion assay.

Adhesion-based microfluidic cell separation has proven to be very useful in applications ranging from cancer diagnostics to tissue engineering. This process involves functionalizing microchannel surfaces with a capture molecule. High specificity and purity capture can be achieved using this method. Despite these advances, little is known about the mechanisms that govern cell capture within these devices and their relationships to basic process parameters such as fluid shear stress and the presence of soluble factors. This work examines how the adhesion of human endothelial cells (ECs) is influenced by a soluble tetrapeptide, Arg-Glu-Asp-Val (REDV) and fluidic shear stress. The ability of these ECs to bind within microchannels coated with REDV is shown to be governed by shear- and soluble-factor mediated changes in p38 mitogen-activated protein kinase expression together with recycling of adhesion receptors from the endosome.

High throughput capture of circulating tumor cells using an integrated microfluidic system

In this work, we introduced an integrated microfluidic system for fast and efficient circulating tumor cell (CTC) isolation and capture. In this microfluidic platform, a combination of microfluidic deterministic lateral displacement array and affinity-based cell capture architecture, allows for the high efficiency cancer cell enrichment and continuous high throughput and purity cancer cell capture. Using this device to isolate breast cancer cells from spiked blood samples, we achieved an enrichment factor of 1500×, and a high processing throughput of 9.6mL/min with 90% capture yield and more than 50% capture purity at cell concentration 102cells/mL. This integrated platform offers a promising approach for CTC capture with high recovery rates, purity and stability, and exhibits potential capability in cancer cell culture and drug screening.

Immunomagnetic nanoscreening of circulating tumor cells with a motion controlled microfluidic system.

Combining the power of immunomagnetic assay and microfluidic microchip operations, we successfully detected rare CTCs from clinical blood samples. The microfluidic system is operated in a flip-flop mode, where a computer-controlled rotational holder with an array of microfluidic chips inverts the microchannels. We have demonstrated both theoretically and experimentally that the direction of red blood cell (RBC) sedimentation with regards to the magnetic force required for cell separation is important for capture efficiency, throughput, and purity. The flip-flop operation reduces the stagnation of RBCs and non-specific binding on the capture surface by alternating the direction of the magnetic field with respect to gravity. The developed immunomagnetic microchip-based screening system exhibits high capture rates (more than 90%) for SkBr3, PC3, and Colo205 cell lines in spiked screening experiments and successfully isolates CTCs from patient blood samples. The proposed motion controlled microchip-based immunomagnetic system shows great promise as a clinical tool for cancer diagnosis and prognosis.

CO2 capture in natural gas combined cycle with SEWGS. Part A: Thermodynamic performances

An innovative process for CO2 capture named SEWGS (sorption enhanced water gas shift) was investigated from technical and economic point of view when applied to natural gas power plants. This activity was carried out under the FP7 project CAESAR financed by the EU community. The SEWGS working conditions were optimized in terms of carbon capture ratio and purity of the CO2 separated as well as number of vessels adopted. Moreover, two different types of sorbent, Sorbent Alfa and Sorbent Beta, were considered in order to evaluate the impact of sorbent cyclic capacity on system performances. Results show that SEWGS with Sorbent Alfa can avoid 91% of CO2 emissions reducing the efficiency penalty of amine scrubbing technologies from 8.4% to 7.2%with a CO2 avoided of 91%. No significant impact of CO2 purity on system performances was determined.The adoption of Sorbent Beta, which has an improved capacity of 60% than Sorbent Alfa, can further reduce specific primary energy consumption for CO2 avoided together with vessel number.The best overall performance in terms of specific primary energy consumption for CO2 avoided has a net electrical efficiency of 51.93% and CO2 avoided of 86%. Part B presents the economic assessment of the investigated cases together with three reference cases selected for electricity production with and without CO2 capture in order to benchmark the innovative solution.

What Can Meta‐Analyses Tell Us About the Reliability of Life Cycle Assessment for Decision Support?

The body of life cycle assessment (LCA) literature is vast and has grown over the last decade at a dauntingly rapid rate. Many LCAs have been published on the same or very similar technologies or products, in some cases leading to hundreds of publications. One result is the impression among decision makers that LCAs are inconclusive, owing to perceived and real variability in published estimates of life cycle impacts. Despite the extensive available literature and policy need formore conclusive assessments, only modest attempts have been made to synthesize previous research. A significant challenge to doing so are differences in characteristics of the considered technologies and inconsistencies in methodological choices (e.g., system boundaries, coproduct allocation, and impact assessment methods) among the studies that hamper easy comparisons and related decision support. An emerging trend is meta-analysis of a set of results from LCAs, which has the potential to clarify the impacts of a particular technology, process, product, or material and produce more robust and policy-relevant results. Meta-analysis in this context is defined here as an analysis of a set of published LCA results to estimate a single or multiple impacts for a single technology or a technology category, either in a statisticalmore » sense (e.g., following the practice in the biomedical sciences) or by quantitative adjustment of the underlying studies to make them more methodologically consistent. One example of the latter approach was published in Science by Farrell and colleagues (2006) clarifying the net energy and greenhouse gas (GHG) emissions of ethanol, in which adjustments included the addition of coproduct credit, the addition and subtraction of processes within the system boundary, and a reconciliation of differences in the definition of net energy metrics. Such adjustments therefore provide an even playing field on which all studies can be considered and at the same time specify the conditions of the playing field itself. Understanding the conditions under which a meta-analysis was conducted is important for proper interpretation of both the magnitude and variability in results. This special supplemental issue of the Journal of Industrial Ecology includes 12 high-quality metaanalyses and critical reviews of LCAs that advance understanding of the life cycle environmental impacts of different technologies, processes, products, and materials. Also published are three contributions on methodology and related discussions of the role of meta-analysis in LCA. The goal of this special supplemental issue is to contribute to the state of the science in LCA beyond the core practice of producing independent studies on specific products or technologies by highlighting the ability of meta-analysis of LCAs to advance understanding in areas of extensive existing literature. The inspiration for the issue came from a series of meta-analyses of life cycle GHG emissions from electricity generation technologies based on research from the LCA Harmonization Project of the National Renewable Energy Laboratory (NREL), a laboratory of the U.S. Department of Energy, which also provided financial support for this special supplemental issue. (See the editorial from this special supplemental issue [Lifset 2012], which introduces this supplemental issue and discusses the origins, funding, peer review, and other aspects.) The first article on reporting considerations for meta-analyses/critical reviews for LCA is from Heath and Mann (2012), who describe the methods used and experience gained in NREL's LCA Harmonization Project, which produced six of the studies in this special supplemental issue. Their harmonization approach adapts key features of systematic review to identify and screen published LCAs followed by a meta-analytical procedure to adjust published estimates to ones based on a consistent set of methods and assumptions to allow interstudy comparisons and conclusions to be made. In a second study on methods, Zumsteg and colleagues (2012) propose a checklist for a standardized technique to assist in conducting and reporting systematic reviews of LCAs, including meta-analysis, that is based on a framework used in evidence-based medicine. Widespread use of such a checklist would facilitate planning successful reviews, improve the ability to identify systematic reviews in literature searches, ease the ability to update content in future reviews, and allow more transparency of methods to ease peer review and more appropriately generalize findings. Finally, Zamagni and colleagues (2012) propose an approach, inspired by a meta-analysis, for categorizing main methodological topics, reconciling diverging methodological developments, and identifying future research directions in LCA. Their procedure involves the carrying out of a literature review on articles selected according to predefined criteria.« less

Meta‐Analysis of Life Cycle Assessment Studies on Electricity Generation with Carbon Capture and Storage

SummaryIn the last decade, numerous life cycle assessments (LCAs) on environmental impacts of electricity generation with carbon capture and storage (CCS) have been conducted. This meta‐analysis comprises 15 LCAs of the three CCS technologies (postcombustion, oxyfuel, precombustion) with a focus on greenhouse gas reduction for different regions (Europe, United States, Japan, global), different fuels (hard coal, lignite, natural gas), and different time horizons (between the present and 2050). It presents a condensed overview of methodological variations, findings, and conclusions gathered from these LCAs.All LCAs show the expected reduction in global warming potential but an increase in many other impact categories, regardless of capture technology, time horizon, or fuel considered. Three parameter sets have been identified that have a significant impact on the results: (1) power plant efficiency and energy penalty of the capture process, (2) carbon dioxide capture efficiency and purity, and (3) fuel origin and composition.This meta‐analysis proves that LCA is a helpful tool to investigate the variety of environmental consequences associated with CCS. However, there are differences in the underlying assumptions of the LCAs as well as methodological shortcomings that yield heterogeneity of results. Without a better understanding of the technology, it is not possible to give a comprehensive picture. There also remains a wide field of subjects and technologies that have not yet been covered.

Abstract 4891: Molecular and functional analysis of circulating tumor cells in castrate resistant prostate cancer using a geometrically enhanced microfluidic device based on PSMA immunocapture

Abstract Prostate cancer (PC) is the most common type of cancer in males and the second leading cause of male cancer deaths in the United States. Circulating tumor cells (CTCs) are commonly found in the blood of metastatic patients and the capture of these cells is important in the study of disease progression. We have developed a geometrically enhanced differential immunocapture (GEDI) microfluidic device coated with the prostate-specific membrane antigen (PSMA) which captures prostate CTCs with high purity and efficiency. This device is designed with a staggered obstacle array in order to maximize the capture efficiency (>80%) and purity (70%) of CTCs. We have used this device to capture, enumerate and molecularly characterize CTCs isolated from 1 ml of blood from patients with castrate resistant prostate cancer (CRPC). First, we compared the capture efficiency from 16 CRPC patients’ blood and subjected it to CTC enumeration by either the GEDI device or the FDA approved CellSearch technology (EpCAM-based immunocapture). Our results showed a 2-350 fold enrichment in CTC counts by the GEDI (range 15-1200 CTCs/ml, median 54). In addition, there was minimal false positive CTC detection in healthy donor blood analyzed by the GEDI. Next we sought to characterize the captured CTCs using multiplex immunofluorescence for proteins specific for PC like androgen receptor (AR), PSMA, TMPRSS2-ERG, EpCAM and other markers involved in epithelial to mesenchymal transition (EMT). We observed low or lack of EpCAM expression in the captured PSMA+/CD45- CTCs, concomitant with high vimentin expression, suggesting that our device may be preferentially capturing CTCs that have undergone EMT. Using the GEDI device, we are able to detect a known single point mutation in the AR using cDNA extracted from approximately 50 C4-2 cells spiked into 1 ml of blood from a healthy donor. Importantly, we have captured CTCs from different CRPC patients and treated them ex vivo with docetaxel to assess effective drug-target engagement by determining the extent of microtubule (MT) stabilization and apoptotic cell death. Our results showed non-uniform CTC response to drug treatment, such that a subset of PSMA+/CD45- CTCs showed MT bundling, indicating tumor heterogeneity and further suggesting that we can potentially use this device to predict patient response to taxane-based chemotherapy. In summary, the GEDI microfluidic device is a novel and specific technology to isolate and characterize PC CTCs at the molecular level. We plan to use this device in prospective clinical studies in order to understand the molecular basis of disease progression and response to taxane-based chemotherapy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4891. doi:10.1158/1538-7445.AM2011-4891

Environmental evaluation of CCS using Life Cycle Assessment–A synthesis report

In the last years several studies have investigated carbon capture and storage (CCS) from a life cycle perspective focusing on the environmental performance. Scope of this study is to compare systematically the different approaches, to summarise the results, address methodological variations and formulate guidelines to assign the various conclusions gathered from the studies. CCS is a wide field with various technological options. All studies show the expected reduction in GWP but often an increase in other impact categories, regardless of capture technology and fuel considered. Three parameter sets have been identified, which have a significant impact on the results: (a) Development of plant efficiencies and energy penalties; (b) Capture efficiency and purity of the CO2; (c) Fuel origin and composition. Although there are still big differences in the underlying assumptions of the studies and also some methodological shortcomings, Life Cycle Assessment (LCA) has proved to be a helpful tool to investigate the environmental consequences related to the introduction of CCS. Nevertheless, the number of existing studies is not sufficient to give a comprehensive picture and there is still a wide field of subjects and technologies which have not been covered yet.