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result(s) for
"Moser, Armin"
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Monolayer coverage and channel length set the mobility in self-assembled monolayer field-effect transistors
by
Mathijssen, Simon G. J.
,
van Hal, Paul A.
,
Janssen, René A. J.
in
Carrier injection
,
Charge transport
,
Chemistry and Materials Science
2009
The mobility of self-assembled monolayer field-effect transistors (SAMFETs) traditionally decreases dramatically with increasing channel length. Recently, however, SAMFETs using liquid-crystalline molecules have been shown to have bulk-like mobilities that are virtually independent of channel length. Here, we reconcile these scaling relations by showing that the mobility in liquid crystalline SAMFETs depends exponentially on the channel length only when the monolayer is incomplete. We explain this dependence both numerically and analytically, and show that charge transport is not affected by carrier injection, grain boundaries or conducting island size. At partial coverage, that is when the monolayer is incomplete, liquid-crystalline SAMFETs thus form a unique model system to study size-dependent conductance originating from charge percolation in two dimensions.
The mobility of field-effect transistors made from self-assembled monolayers of liquid-crystal molecules depends on channel length only when the monolayer coverage is incomplete.
Journal Article
A General Small-Angle X-ray Scattering-Based Screening Protocol for Studying Physical Stability of Protein Formulations
2021
A fundamental step in developing a protein drug is the selection of a stable storage formulation that ensures efficacy of the drug and inhibits physiochemical degradation or aggregation. Here, we designed and evaluated a general workflow for screening of protein formulations based on small-angle X-ray scattering (SAXS). Our SAXS pipeline combines automated sample handling, temperature control, and fast data analysis and provides protein particle interaction information. SAXS, together with different methods including turbidity analysis, dynamic light scattering (DLS), and SDS-PAGE measurements, were used to obtain different parameters to provide high throughput screenings. Using a set of model proteins and biopharmaceuticals, we show that SAXS is complementary to dynamic light scattering (DLS), which is widely used in biopharmaceutical research and industry. We found that, compared to DLS, SAXS can provide a more sensitive measure for protein particle interactions, such as protein aggregation and repulsion. Moreover, we show that SAXS is compatible with a broader range of buffers, excipients, and protein concentrations and that in situ SAXS provides a sensitive measure for long-term protein stability. This workflow can enable future high-throughput analysis of proteins and biopharmaceuticals and can be integrated with well-established complementary physicochemical analysis pipelines in (biopharmaceutical) research and industry.
Journal Article
Comprehensive Analysis of Key Parameters Determining Formation and Structural Properties of Sol–Gel‐Derived Nanoporous Polymers
2026
This study presents a comprehensive investigation on the relationship between structure, synthesis parameters, and porous properties of sol–gel‐derived polymer gels. The formation of the porous gels is monitored with in situ small‐angle X‐ray scattering, in situ nuclear magnetic resonance spectroscopy (NMR), and NMR cryoporometry. The transition of the reaction solution to a solid gel is governed by the consumption of the phenolic monomer. Primary particle growth and nanopore formation proceed during this short time period and are completed when all resorcinol is consumed. The kinetics of these processes are temperature‐dependent and they are completed within 12 min at 120 °C and within 60 min at 80 °C. Extending the reaction time further results in enhanced cross‐linking of the polymer, as observed by solid‐state 13C NMR spectroscopy. Extended reaction time, i.e., higher degree of polymer cross‐linking, enhances pore stability and reduces gel shrinkage during drying, resulting in xerogels with larger pore volume, larger external surface area, and larger average pore sizes. This work rationalizes molecular‐scale transformation of polymers with macroscopic properties, thus providing a rational tool for tuning aerogel/xerogel performance through synthesis design. A comprehensive study shows that chemical composition of the gelation mixture determines the primary particles size and the size of pores they form. Reaction temperature and time define the degree of cross‐linking within the polymer and thus determine the mechanical strength of the gel. High mechanical strength results in low degree of shrinkage during thermal drying.
Journal Article
Inference of transcription factor binding from cell-free DNA enables tumor subtype prediction and early detection
2019
Deregulation of transcription factors (TFs) is an important driver of tumorigenesis, but non-invasive assays for assessing transcription factor activity are lacking. Here we develop and validate a minimally invasive method for assessing TF activity based on cell-free DNA sequencing and nucleosome footprint analysis. We analyze whole genome sequencing data for >1,000 cell-free DNA samples from cancer patients and healthy controls using a bioinformatics pipeline developed by us that infers accessibility of TF binding sites from cell-free DNA fragmentation patterns. We observe patient-specific as well as tumor-specific patterns, including accurate prediction of tumor subtypes in prostate cancer, with important clinical implications for the management of patients. Furthermore, we show that cell-free DNA TF profiling is capable of detection of early-stage colorectal carcinomas. Our approach for mapping tumor-specific transcription factor binding in vivo based on blood samples makes a key part of the noncoding genome amenable to clinical analysis.
Deregulation of transcription factors is frequently observed in cancer. Here, the authors develop a blood-based approach to map transcription factor binding, revealing both patient-specific and tumour-specific aberrations
Journal Article
The elevated preoperative platelet to lymphocyte ratio predicts decreased time to recurrence in colon cancer patients
2014
Recent evidence indicates that tumor progression involves factors of systemic inflammation, such as platelets and lymphocytes. In this study, we investigated the prognostic relevance of the preoperative platelet to lymphocyte (P/L) ratio on time to recurrence (TTR) and overall survival (OS) in patients with stage II and III colon cancer (CC) who underwent curative resection.
In this retrospective study, 372 CC patients were included. Kaplan–Meier curves and multivariate Cox proportional models were calculated for TTR and OS.
In univariate analysis, the elevated P/L ratio was significantly associated with decreased TTR (HR = 1.60, 95% CI = 1.02 to 2.51, P = .040) and remained significant in multivariate analysis (HR = 1.65, 95% CI = 1.05 to 2.58, P = .030), where HR and CI represent Hazard ratio and confidence interval, respectively. Patients with elevated P/L ratio showed a median TTR of 116 months. In contrast, patients with low P/L ratio had a median TTR of 132 months. In OS analysis, the elevated P/L ratio showed a trend toward decreased OS in univariate analysis (HR = 1.54, 95% CI = .95 to 2.48, P = .079).
In this study, we identified the preoperative P/L ratio as a prognostic marker for TTR in stage II and III CC patients.
Journal Article
Publisher Correction: Inference of transcription factor binding from cell-free DNA enables tumor subtype prediction and early detection
2020
An amendment to this paper has been published and can be accessed via a link at the top of the paper.An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Journal Article
Integration of a CD19 CAR into the TCR Alpha Chain Locus Streamlines Production of Allogeneic Gene-Edited CAR T Cells
2017
Adoptive cellular therapy using chimeric antigen receptor (CAR) T cell therapies have produced significant objective responses in patients with CD19+ hematological malignancies, including durable complete responses. Although the majority of clinical trials to date have used autologous patient cells as the starting material to generate CAR T cells, this strategy poses significant manufacturing challenges and, for some patients, may not be feasible because of their advanced disease state or difficulty with manufacturing suitable numbers of CAR T cells. Alternatively, T cells from a healthy donor can be used to produce an allogeneic CAR T therapy, provided the cells are rendered incapable of eliciting graft versus host disease (GvHD). One approach to the production of these cells is gene editing to eliminate expression of the endogenous T cell receptor (TCR). Here we report a streamlined strategy for generating allogeneic CAR T cells by targeting the insertion of a CAR transgene directly into the native TCR locus using an engineered homing endonuclease and an AAV donor template. We demonstrate that anti-CD19 CAR T cells produced in this manner do not express the endogenous TCR, exhibit potent effector functions in vitro, and mediate clearance of CD19+ tumors in an in vivo mouse model.
MacLeod and colleagues use a homing endonuclease and an AAV vector to insert an anti-CD19 CAR into the TRAC gene to create universal allogeneic CAR T cells. Targeted insertion of a CAR transgene may allow the generation of more homogeneous CAR T cell products with more predictable safety and efficacy profiles.
Journal Article
External Validation of the Derived Neutrophil to Lymphocyte Ratio as a Prognostic Marker on a Large Cohort of Pancreatic Cancer Patients
2013
With growing evidence on the role of inflammation in cancer biology, the presence of a systemic inflammatory response has been postulated as having prognostic significance in a wide range of cancer types. The derived neutrophil to lymphocyte ratio (dNLR), which represents an easily determinable potential prognostic marker in daily practise and clinical trials, has never been externally validated in pancreatic cancer (PC) patients.
Data from 474 consecutive PC patients, treated between 2004 and 2012 at a single centre, were evaluated retrospectively. Cancer-specific survival (CSS) was assessed using the Kaplan-Meier method. To evaluate the prognostic relevance of dNLR, univariate and multivariate Cox regression models were applied.
We calculated by ROC analysis a cut-off value of 2.3 for the dNLR to be ideal to discriminate between patients' survival in the whole cohort. Kaplan-Meier curve reveals a dNLR≥2.3 as a factor for decreased CSS in PC patients (p<0.001, log-rank test). An independent significant association between high dNLR≥2.3 and poor clinical outcome in multivariate analysis (HR = 1.24, CI95% = 1.01-1.51, p = 0.041) was identified.
In the present study we confirmed elevated pre-treatment dNLR as an independent prognostic factor for clinical outcome in PC patients. Our data encourage independent replication in other series and settings of this easily available parameter as well as stratified analysis according to tumor resectability.
Journal Article
Benefit of second-line systemic chemotherapy for advanced biliary tract cancer: A propensity score analysis
by
Gerger, Armin
,
Rossmann, Christopher H.
,
Bauernhofer, Thomas
in
692/308/409
,
692/4028/67/1504/1329
,
Aged
2019
Whether 2
nd
-line-chemotherapy (2LCTX) + best-supportive-care (BSC) benefits patients with advanced biliary tract cancer (aBTC) more than BSC alone is unclear. We therefore conducted a propensity-score-based comparative effectiveness analysis of overall survival (OS) outcomes in 80 patients with metastatic, recurrent, or inoperable aBTC, of whom 38 (48%) were treated with BSC + 2LCTX and 42 (52%) with BSC alone. After a median follow-up of 14.8 months and 49 deaths, the crude 6-, 12-, and 18-month Kaplan-Meier OS estimates were 77%, 53% and 23% in the BSC + 2LCTX group, and 29%, 21%, and 14% in patients in the BSC group (p = 0.0003; Hazard ratio (HR) = 0.36, 95%CI:0.20–0.64, p = 0.001). An inverse-probability-of-treatment-weighted (IPTW) analysis was conducted to rigorously account for the higher prevalence of favorable prognostic variables in the 2LCTX + BSC group. After IPTW-weighting, the favorable association between 2LCTX and OS prevailed (adjusted HR = 0.40, 95%CI: 0.17–0.95, p = 0.037). IPTW-weighted 6-, 12-, and 18-month OS estimates were 77%, 58% and 33% in the BSC + 2LCTX group, and 39%, 28% and 22% in the BSC group (p = 0.037). Moreover, the benefit of 2LCTX was consistent across several clinically-relevant subgroups. Within the limitations of an observational study, these findings support the concept that 2LCTX + BSC is associated with an OS benefit over BSC alone in aBTC.
Journal Article
Evaluation of polarimetric ice microphysical retrievals with OLYMPEX campaign data
2023
Polarimetric microphysical retrievals reveal a great potential for the evaluation of numerical models and data assimilation. However, the accuracy of ice microphysical retrievals is still poorly explored. To evaluate these retrievals and assess their accuracy, polarimetric radar measurements are spatially and temporally collocated with in situ aircraft measurements obtained during the OLYMPEX campaign (Olympic Mountain Experiment). Retrievals for ice water content (IWC), total number concentration Nt, and mean volume diameter Dm of ice particles are assessed by comparing an in situ dataset obtained by the University of North Dakota (UND) Citation II aircraft with X-band Doppler on Wheels (DOW) measurements. Sector-averaged range height indicator (RHI) scans are used to derive vertical profiles of microphysical retrievals. The comparison of these estimates with in situ data provides insights into strengths, weaknesses, and the accuracy of the different retrievals and quantifies the improvements in polarimetry-informed retrievals compared to conventional, non-polarimetric ones. In particular, the recently introduced hybrid ice water content retrieval exploiting reflectivity ZH, differential reflectivity ZDR, and specific differential phase KDP outperforms other retrievals based on either (ZH, ZDR) or (ZH, KDP) or non-polarimetric retrievals in terms of correlations with in situ measurements and the root mean square error.
Journal Article