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1.
J Am Chem Soc ; 146(6): 3963-3973, 2024 Feb 14.
Article in English | MEDLINE | ID: mdl-38305745

ABSTRACT

One of the challenges for the realization of molecular electronics is the design of nanoscale molecular wires displaying long-range charge transport. Graphene nanoribbons are an attractive platform for the development of molecular wires with long-range conductance owing to their unique electrical properties. Despite their potential, the charge transport properties of single nanoribbons remain underexplored. Herein, we report a synthetic approach to prepare N-doped pyrene-pyrazinoquinoxaline molecular graphene nanoribbons terminated with diamino anchoring groups at each end. These terminal groups allow for the formation of stable molecular graphene nanoribbon junctions between two metal electrodes that were investigated by scanning tunneling microscope-based break-junction measurements. The experimental and computational results provide evidence of long-range tunneling charge transport in these systems characterized by a shallow conductance length dependence and electron tunneling through >6 nm molecular backbone.

2.
Clin Lung Cancer ; 24(5): 407-414, 2023 07.
Article in English | MEDLINE | ID: mdl-37012147

ABSTRACT

BACKGROUND: Indeterminate pulmonary nodules present a common challenge for clinicians who must recommend surveillance or intervention based on an assessed risk of malignancy. PATIENTS AND METHODS: In this cohort study, patients presenting for indeterminate pulmonary nodule evaluation were enrolled at sites participating in the Colorado SPORE in Lung Cancer. They were followed prospectively and included for analysis if they had a definitive malignant diagnosis, benign diagnosis, or radiographic resolution or stability of their nodule for > 2 years. RESULTS: Patients evaluated at the Veterans Affairs (VA) and non-VA sites were equally as likely to have a malignant diagnosis (48%). The VA cohort represented a higher-risk group than the non-VA cohort regarding smoking history and chronic obstructive pulmonary disease (COPD). There were more squamous cell carcinoma diagnoses among VA malignant nodules (25% vs. 10%) and a later stage at diagnosis among VA patients. Discrimination and calibration of risk calculators produced estimates that were wide-ranging and different when comparing between risk score calculators as well as between VA/non-VA cohorts. Application of current American College of Chest Physicians guidelines to our groups could have resulted in inappropriate resection of 12% of benign nodules. CONCLUSION: Comparison of VA with non-VA patients shows important differences in underlying risk, histology of malignant nodules, and stage at diagnosis. This study highlights the challenge in applying risk calculators to a clinical setting, as the model discrimination and calibration were variable between calculators and between our higher-risk VA and lower-risk non-VA groups. MICROABSTRACT: Risk stratification and management of indeterminate pulmonary nodules (IPNs) is a common clinical problem. In this prospective cohort study of 282 patients with IPNs from Veterans Affairs (VA) and non-VA sites, we found differences in patient and nodule characteristics, histology and diagnostic stage, and risk calculator performance. Our findings highlight challenges and shortcomings of current IPN management guidelines and tools.


Subject(s)
Lung Neoplasms , Multiple Pulmonary Nodules , Solitary Pulmonary Nodule , Humans , Lung Neoplasms/pathology , Cohort Studies , Prospective Studies , Multiple Pulmonary Nodules/diagnosis , Multiple Pulmonary Nodules/pathology , Risk Factors , Solitary Pulmonary Nodule/diagnosis
3.
JTO Clin Res Rep ; 2(3): 100110, 2021 Mar.
Article in English | MEDLINE | ID: mdl-34589992

ABSTRACT

INTRODUCTION: Blood-based next-generation sequencing assays of circulating tumor DNA (ctDNA) have the ability to detect tumor-associated mutations in patients with SCLC. We sought to characterize the relationship between ctDNA mean variant allele frequency (VAF) and radiographic total-body tumor volume (TV) in patients with SCLC. METHODS: We identified matched blood draws and computed tomography (CT) or positron emission tomography (PET) scans within a prospective SCLC blood banking cohort. We sequenced plasma using our previously developed 14-gene SCLC-specific ctDNA assay. Three-dimensional TV was determined from PET and CT scans using MIM software and reviewed by radiation oncologists. Univariate association and multivariate regression analyses were performed to evaluate the association between mean VAF and total-body TV. RESULTS: We analyzed 75 matched blood draws and CT or PET scans from 25 unique patients with SCLC. Univariate analysis revealed a positive association between mean VAF and total-body TV (Spearman's ρ = 0.292, p < 0.01), and when considering only treatment-naive and pretreatment patients (n = 11), there was an increase in the magnitude of association (ρ = 0.618, p = 0.048). The relationship remained significant when adjusting for treatment status and bone metastases (p = 0.046). In the subgroup of patients with TP53 variants, univariate analysis revealed a significant association (ρ = 0.762, p = 0.037) only when considering treatment-naive and pretreatment patients (n = 8). CONCLUSIONS: We observed a positive association between mean VAF and total-body TV in patients with SCLC, suggesting mean VAF may represent a dynamic biomarker of tumor burden that could be followed to monitor disease status.

5.
N Engl J Med ; 384(25): 2382-2393, 2021 06 24.
Article in English | MEDLINE | ID: mdl-34161704

ABSTRACT

BACKGROUND: Clinical trials of the KRAS inhibitors adagrasib and sotorasib have shown promising activity in cancers harboring KRAS glycine-to-cysteine amino acid substitutions at codon 12 (KRASG12C). The mechanisms of acquired resistance to these therapies are currently unknown. METHODS: Among patients with KRASG12C -mutant cancers treated with adagrasib monotherapy, we performed genomic and histologic analyses that compared pretreatment samples with those obtained after the development of resistance. Cell-based experiments were conducted to study mutations that confer resistance to KRASG12C inhibitors. RESULTS: A total of 38 patients were included in this study: 27 with non-small-cell lung cancer, 10 with colorectal cancer, and 1 with appendiceal cancer. Putative mechanisms of resistance to adagrasib were detected in 17 patients (45% of the cohort), of whom 7 (18% of the cohort) had multiple coincident mechanisms. Acquired KRAS alterations included G12D/R/V/W, G13D, Q61H, R68S, H95D/Q/R, Y96C, and high-level amplification of the KRASG12C allele. Acquired bypass mechanisms of resistance included MET amplification; activating mutations in NRAS, BRAF, MAP2K1, and RET; oncogenic fusions involving ALK, RET, BRAF, RAF1, and FGFR3; and loss-of-function mutations in NF1 and PTEN. In two of nine patients with lung adenocarcinoma for whom paired tissue-biopsy samples were available, histologic transformation to squamous-cell carcinoma was observed without identification of any other resistance mechanisms. Using an in vitro deep mutational scanning screen, we systematically defined the landscape of KRAS mutations that confer resistance to KRASG12C inhibitors. CONCLUSIONS: Diverse genomic and histologic mechanisms impart resistance to covalent KRASG12C inhibitors, and new therapeutic strategies are required to delay and overcome this drug resistance in patients with cancer. (Funded by Mirati Therapeutics and others; ClinicalTrials.gov number, NCT03785249.).


Subject(s)
Acetonitriles/therapeutic use , Carcinoma, Non-Small-Cell Lung/drug therapy , Colorectal Neoplasms/drug therapy , Drug Resistance, Neoplasm/genetics , Lung Neoplasms/drug therapy , Mutation , Piperazines/therapeutic use , Proto-Oncogene Proteins p21(ras)/genetics , Pyrimidines/therapeutic use , Appendiceal Neoplasms/drug therapy , Appendiceal Neoplasms/genetics , Carcinoma, Non-Small-Cell Lung/genetics , Colorectal Neoplasms/genetics , Humans , Lung Neoplasms/genetics , Protein Conformation , Proto-Oncogene Proteins p21(ras)/antagonists & inhibitors , Proto-Oncogene Proteins p21(ras)/ultrastructure , Pyridines/therapeutic use
6.
J Phys Chem Lett ; 11(22): 9766-9774, 2020 Nov 19.
Article in English | MEDLINE | ID: mdl-33142062

ABSTRACT

Multi-heme cytochromes (MHCs) are fascinating proteins used by bacterial organisms to shuttle electrons within, between, and out of their cells. When placed in solid-state electronic junctions, MHCs support temperature-independent currents over several nanometers that are 3 orders of magnitude higher compared to other redox proteins of similar size. To gain molecular-level insight into their astonishingly high conductivities, we combine experimental photoemission spectroscopy with DFT+Σ current-voltage calculations on a representative Gold-MHC-Gold junction. We find that conduction across the dry, 3 nm long protein occurs via off-resonant coherent tunneling, mediated by a large number of protein valence-band orbitals that are strongly delocalized over heme and protein residues. This picture is profoundly different from the electron hopping mechanism induced electrochemically or photochemically under aqueous conditions. Our results imply that the current output in solid-state junctions can be even further increased in resonance, for example, by applying a gate voltage, thus allowing a quantum jump for next-generation bionanoelectronic devices.


Subject(s)
Hemeproteins/chemistry , Cytochromes/chemistry , Density Functional Theory , Electric Conductivity , Electrochemical Techniques , Electron Transport , Gold/chemistry , Heme/chemistry , Models, Molecular , Oxidation-Reduction , Photochemical Processes , Protein Conformation , Water
8.
JTO Clin Res Rep ; 1(2): 100024, 2020 Jun.
Article in English | MEDLINE | ID: mdl-34589931

ABSTRACT

INTRODUCTION: Most patients (70%) with limited-stage SCLC (LS-SCLC) who are treated with curative-intent therapy suffer disease relapse and cancer-related death. We evaluated circulating tumor DNA (ctDNA) as a predictor of disease relapse and death after definitive therapy in patients with LS-SCLC. METHODS: In our previous work, we developed a plasma-based ctDNA assay to sequence 14 genes (TP53, RB1, BRAF, KIT, NOTCH1-4, PIK3CA, PTEN, FGFR1, MYC, MYCL1, and MYCN) that are frequently mutated in SCLC. In this work, we evaluated 177 plasma samples from 23 patients with LS-SCLC who completed definitive chemoradiation (n = 21) or surgical resection (n = 2) and had an end-of-treatment blood collection (median 4 d, range 0-40 d from treatment completion) plus monthly surveillance blood sampling. Median overall survival (OS) and progression-free survival (PFS) were compared using a Wilcoxon test. RESULTS: The median OS among patients in whom we ever detected ctDNA after definitive treatment (n = 15) was 18.2 months compared with a median OS of greater than 48 months among patients in whom we never detected ctDNA after definitive treatment (n = 8; p = 0.081). The median PFS among patients in whom we ever detected ctDNA after definitive treatment was 9.1 months compared with a median PFS of greater than 48 months among patients in whom we never detected ctDNA after definitive treatment (p < 0.001). CONCLUSIONS: Detection of ctDNA in patients with LS-SCLC after curative-intent therapy predicts disease relapse and death. Prospective trials using ctDNA as an integral biomarker for therapeutic selection should be considered in SCLC.

9.
Diabetologia ; 62(11): 2017-2024, 2019 11.
Article in English | MEDLINE | ID: mdl-31444527

ABSTRACT

AIMS/HYPOTHESIS: We previously showed that intrauterine exposure to gestational diabetes mellitus (GDM) increases selected markers of adiposity in pre-pubertal adolescents. In the present study, we examined these associations in adolescence, and explored whether they are strengthened as the participants transition through puberty. METHODS: Data from 597 individuals (505 unexposed, 92 exposed) participating in the longitudinal Exploring Perinatal Outcomes among Children (EPOCH) study in Colorado were collected at two research visits when the participants were, on average, 10.4 and 16.7 years old. Adiposity measures included BMI, waist/height ratio, and visceral and subcutaneous adipose tissue (as determined by MRI). Separate general linear mixed models were used to assess the longitudinal relationships between exposure to maternal GDM and each adiposity outcome. We tested whether the effect changed over time by including an interaction term between exposure and age in our models, and whether the associations were explained by postnatal behaviours. RESULTS: Compared with unexposed participants, those exposed to maternal GDM had higher BMI (ß = 1.28; 95% CI 0.35, 2.21; p < 0.007), waist/height ratio (ß = 0.03; 95% CI 0.01, 0.04; p = 0.0004), visceral adipose tissue (ß = 4.81; 95% CI 1.08, 8.54; p = 0.01) and subcutaneous adipose tissue (ß = 35.15; 95% CI 12.43, 57.87; p < 0.003). The magnitude of these differences did not change over time and the associations did not appear to be explained by postnatal behaviours. CONCLUSIONS/INTERPRETATION: Our data provide further evidence that intrauterine exposure to maternal GDM is associated with increased offspring adiposity, an effect that appears early in life and tracks throughout adolescence. Efforts to prevent childhood obesity following intrauterine exposure to maternal GDM should target the prenatal or early life periods.


Subject(s)
Adiposity , Diabetes, Gestational/physiopathology , Overnutrition/physiopathology , Prenatal Exposure Delayed Effects , Adipose Tissue/pathology , Adolescent , Body Mass Index , Child , Colorado/epidemiology , Female , Humans , Linear Models , Longitudinal Studies , Magnetic Resonance Imaging , Male , Mothers , Obesity/complications , Overnutrition/complications , Pregnancy , Prospective Studies , Risk Factors , Treatment Outcome
10.
J Thorac Oncol ; 14(11): 1901-1911, 2019 11.
Article in English | MEDLINE | ID: mdl-31446141

ABSTRACT

INTRODUCTION: Despite initial effectiveness of ALK receptor tyrosine kinase inhibitors (TKIs) in patients with ALK+ NSCLC, therapeutic resistance will ultimately develop. Serial tracking of genetic alterations detected in circulating tumor DNA (ctDNA) can be an informative strategy to identify response and resistance. This study evaluated the utility of analyzing ctDNA as a function of response to ensartinib, a potent second-generation ALK TKI. METHODS: Pre-treatment plasma was collected from 76 patients with ALK+ NSCLC who were ALK TKI-naive or had received prior ALK TKI, and analyzed for specific genetic alterations. Longitudinal plasma samples were analyzed from a subset (n = 11) of patients. Analysis of pre-treatment tumor biopsy specimens from 22 patients was compared with plasma. RESULTS: Disease-associated genetic alterations were detected in 74% (56 of 76) of patients, the most common being EML4-ALK. Concordance of ALK fusion between plasma and tissue was 91% (20 of 22 blood and tissue samples). Twenty-four ALK kinase domain mutations were detected in 15 patients, all had previously received an ALK TKI; G1269A was the most prevalent (4 of 24). Patients with a detectable EML4-ALK variant 1 (V1) fusion had improved response (9 of 17 patients; 53%) to ensartinib compared to patients with EML4-ALK V3 fusion (one of seven patients; 14%). Serial changes in ALK alterations were observed during therapy. CONCLUSIONS: Clinical utility of ctDNA was shown, both at pre-treatment by identifying a potential subgroup of ALK+ NSCLC patients who may derive more benefit from ensartinib and longitudinally by tracking resistance. Prospective application of this technology may translate to improved outcomes for NSCLC patients treated with ALK TKIs.


Subject(s)
Anaplastic Lymphoma Kinase/genetics , Circulating Tumor DNA/genetics , Lung Neoplasms/drug therapy , Lung Neoplasms/genetics , Mutation , Piperazines/therapeutic use , Pyridazines/therapeutic use , Adult , Aged , Aged, 80 and over , Anaplastic Lymphoma Kinase/biosynthesis , Carcinoma, Non-Small-Cell Lung/blood , Carcinoma, Non-Small-Cell Lung/drug therapy , Carcinoma, Non-Small-Cell Lung/genetics , Circulating Tumor DNA/blood , Drug Resistance, Neoplasm , Female , Humans , Lung Neoplasms/blood , Male , Middle Aged , Oncogene Proteins, Fusion/genetics , Oncogene Proteins, Fusion/metabolism , Prognosis , Protein Kinase Inhibitors/therapeutic use
11.
J Am Coll Radiol ; 16(10): 1401-1408, 2019 Oct.
Article in English | MEDLINE | ID: mdl-30833166

ABSTRACT

OBJECTIVE: To describe patient perceptions related to CT and evaluate variation related to patient sociodemographic characteristics. METHODS: Institutional review board-approved survey of adult patients undergoing outpatient CT at a large academic hospital administered May 2016 to March 2017. The survey included questions about participant demographic and socioeconomic characteristics as well as scales that addressed five perceptual constructs related to their CT examination: knowledge, benefits, barriers, expectations, and trust. Two of these constructs use the Health Belief Model as a conceptual framework, and questions were adapted from the Benefits and Barriers Scale for Screening Mammography. Descriptive statistics were calculated for all variables. Heterogeneous choice models were used to evaluate associations between participant characteristics and the perceptual constructs. RESULTS: In all, 302 surveys were completed by a diverse patient sample (33% non-Hispanic white, 29% Hispanic or Latino, 24% black, 8% mixed or other race, 5% Asian or Pacific Islander, 2% American Indian or Alaska Native). A large majority of participants responded positively to CT examination perceptions for each item with: high knowledge (71%-97%), positive expectations (94%-98%), high trust (92%) and benefits (67%-93%), and low barriers (only 9%-17% reported). In addition, 26% of participants reported seeking information about the CT before their appointment, with calling their physician's office the most common approach. The heterogeneous choice models found that responses to nearly all of the scale questions did not vary by sociodemographic characteristics, although in a larger sample some associations may be significant. CONCLUSIONS: Among a diverse sample of patients, perceptions of CT examination were highly positive and similar according to sociodemographic characteristics.


Subject(s)
Surveys and Questionnaires , Tomography, X-Ray Computed/psychology , Demography , Ethnicity/statistics & numerical data , Female , Humans , Male , Middle Aged , Pilot Projects , Prospective Studies
12.
J Natl Cancer Inst ; 111(6): 575-583, 2019 Jun 01.
Article in English | MEDLINE | ID: mdl-30496436

ABSTRACT

BACKGROUND: Liquid biopsy for plasma circulating tumor DNA (ctDNA) next-generation sequencing (NGS) is commercially available and increasingly adopted in clinical practice despite a paucity of prospective data to support its use. METHODS: Patients with advanced lung cancers who had no known oncogenic driver or developed resistance to current targeted therapy (n = 210) underwent plasma NGS, targeting 21 genes. A subset of patients had concurrent tissue NGS testing using a 468-gene panel (n = 106). Oncogenic driver detection, test turnaround time (TAT), concordance, and treatment response guided by plasma NGS were measured. All statistical tests were two-sided. RESULTS: Somatic mutations were detected in 64.3% (135/210) of patients. ctDNA detection was lower in patients who were on systemic therapy at the time of plasma collection compared with those who were not (30/70, 42.9% vs 105/140, 75.0%; OR = 0.26, 95% CI = 0.1 to 0.5, P < .001). The median TAT of plasma NGS was shorter than tissue NGS (9 vs 20 days; P < .001). Overall concordance, defined as the proportion of patients for whom at least one identical genomic alteration was identified in both tissue and plasma, was 56.6% (60/106, 95% CI = 46.6% to 66.2%). Among patients who tested plasma NGS positive, 89.6% (60/67; 95% CI = 79.7% to 95.7%) were also concordant on tissue NGS and 60.6% (60/99; 95% CI = 50.3% to 70.3%) vice versa. Patients who tested plasma NGS positive for oncogenic drivers had tissue NGS concordance of 96.1% (49/51, 95% CI = 86.5% to 99.5%), and directly led to matched targeted therapy in 21.9% (46/210) with clinical response. CONCLUSIONS: Plasma ctDNA NGS detected a variety of oncogenic drivers with a shorter TAT compared with tissue NGS and matched patients to targeted therapy with clinical response. Positive findings on plasma NGS were highly concordant with tissue NGS and can guide immediate therapy; however, a negative finding in plasma requires further testing. Our findings support the potential incorporation of plasma NGS into practice guidelines.


Subject(s)
Carcinoma, Non-Small-Cell Lung/genetics , Circulating Tumor DNA/genetics , Lung Neoplasms/genetics , Adult , Aged , Aged, 80 and over , Carcinoma, Non-Small-Cell Lung/blood , Carcinoma, Non-Small-Cell Lung/therapy , Circulating Tumor DNA/blood , Female , Genotyping Techniques , High-Throughput Nucleotide Sequencing/methods , Humans , Liquid Biopsy , Lung Neoplasms/blood , Lung Neoplasms/therapy , Male , Middle Aged , Multiplex Polymerase Chain Reaction , Mutation , Precision Medicine , Prospective Studies
13.
Abdom Radiol (NY) ; 44(2): 705-712, 2019 02.
Article in English | MEDLINE | ID: mdl-30171296

ABSTRACT

PURPOSE: To assess the diagnostic accuracy of PI-RADS v2 categories ≥ 3 to detect clinically significant prostate cancer (csPCa) against histopathology of Transperineal Mapping Biopsy (TPMB). MATERIALS AND METHODS: IRB-approved retrospective cohort study included 47 men who had 3.0 T multi-parametric MRI (mpMRI) and TPMB of prostate. Two radiologists independently evaluated T2, DWI, ADC map, and DCE images using PI-RADS v2 categories. A third radiologist served as tie-breaker. PI-RADS v2 score (PS) ≥ 3 lesions were correlated with 3D model of TPMB (3DTPMB) results based on prostate sectors. Two groups of csPCa status were separately analyzed for accuracy measures at lesion and person levels: Group 1 with GS (Gleason Score) ≥ 7 and group 2 with tumor volume ≥ 0.5 cc. Inter-rater reliability for PS and MR lexicon was calculated. RESULTS: Forty-seven patients with 3DTPMB had at least one lesion with PS ≥ 3 on mpMRI. PS of 5 had high PPV and high specificity of 100% at the lesion and person levels. Sensitivity of a PS ≥ 3 was 68.27% for group 1 and was 48.39% for group 2. Specificity was 93.56% for group 1 and was 95.53% for group 2. At the person level, sensitivity of PS ≥ 3 was 81.25% for group 1 and was 82.35% for group 2. Specificity was 32.26% for group 1 and was 53.85% for group 2. CONCLUSION: PI-RADS v2 category of 5 had high PPV and specificity; however, combined PS ≥ 3 had mixed performance in detection of csPCa.


Subject(s)
Multiparametric Magnetic Resonance Imaging/methods , Prostatic Neoplasms/diagnostic imaging , Prostatic Neoplasms/pathology , Radiology Information Systems/statistics & numerical data , Aged , Cohort Studies , Humans , Male , Middle Aged , Neoplasm Grading , Prostate/diagnostic imaging , Prostate/pathology , Reproducibility of Results , Retrospective Studies , Sensitivity and Specificity
14.
Chem Sci ; 9(37): 7304-7310, 2018 Oct 07.
Article in English | MEDLINE | ID: mdl-30294419

ABSTRACT

Multi-heme cytochrome c (Cytc) proteins are key for transferring electrons out of cells, to enable intracellular oxidation to proceed in the absence of O2. In these proteins most of the hemes are arranged in a linear array suggesting a facile path for electronic conduction. To test this, we studied solvent-free electron transport across two multi-heme Cytc-type proteins: MtrF (deca-heme Cytc) and STC (tetra-heme Cytc). Transport is measured across monolayers of these proteins in a solid state configuration between Au electrodes. Both proteins showed 1000× higher conductance than single heme, or heme-free proteins, but similar conductance to monolayers of conjugated organics. Conductance is found to be temperature-independent (320-80 K), suggesting tunneling as the transport mechanism. This mechanism is consistent with I-V curves modelling, results of which could be interpreted by having protein-electrode coupling as rate limiting, rather than transport within the proteins.

15.
ACS Appl Mater Interfaces ; 10(48): 41599-41607, 2018 Dec 05.
Article in English | MEDLINE | ID: mdl-30376633

ABSTRACT

Different batches of Si wafers with nominally the same specifications were found to respond differently to identical chemical surface treatments aimed at regrowing Si oxide on them. We found that the oxides produced on different batches of wafer differ electrically, thereby affecting solid-state electron transport (ETp) via protein films assembled on them. These results led to the another set of experiments, where we studied this phenomenon using two distinct chemical methods to regrow oxides on the same batch of Si wafers. We have characterized the surfaces of the regrown oxides and of monolayers of linker molecules that connect proteins with the oxides and examined ETp via ultrathin layers of the protein bacteriorhodopsin, assembled on them. Our results illustrate the crucial role of (near) surface charges on the substrate in defining the ETp characteristics across the proteins. This is expressed most strikingly in the observed current's temperature dependences, and we propose that these are governed by the electrostatic landscape at the electrode-protein interface rather than by intrinsic protein properties. This study's major finding, relevant to protein bioelectronics, is that protein-electrode coupling in junctions is a decisive factor in ETp across them. Hence,surface electrostatics can create a barrier that dominates charge transport and controls the transport mode across the junction. Our findings' wider importance lies in their relevance to hybrid junctions of Si with (polyelectrolyte) biomolecules, a likely direction for future bioelectronics. A remarkable corollary of presented results is that once an electron is injected into the protein, transport within the proteins is so efficient that it does not encounter a measurable barrier down to 160 K.


Subject(s)
Bacteriorhodopsins/chemistry , Electron Transport , Surface Properties
17.
Nanoscale ; 10(8): 3730-3737, 2018 Feb 22.
Article in English | MEDLINE | ID: mdl-29411826

ABSTRACT

Nano-scale patterns such as those found on the exterior surface of the eyes of certain nocturnal insects have far-reaching implications in terms of optoelectronic device design. The advantage of using these patterns for optoelectronic enhancement in photovoltaic light harvesting has been less explored due to the lack of suitable engineered materials to easily fabricate such nanostructures. Here, an attempt is made to realize these complex patterns using a self-assembly based molding process on hitherto unexplored robust structural epoxies with excellent repeatability and scalability to a larger area. The incorporation of these patterns in the substrate shows nearly a 50% broadband drop in the specular reflectance of the nanostructured substrate. Furthermore, it is demonstrated that by tweaking the bio-inspired patterns on the interior side of a light harvesting device, it is possible to obtain a broadband improvement in the external quantum efficiency in the spectral window between 350 and 650 nm leading to a significant improvement of up to 49% in the photocurrent density in the structured devices. From our experiment and simulations, it is observed that this enhancement stems from a combination of two effects: first, a broadband drop in the specular reflectance exceeding 70%, arising from trapped surface plasmon-polariton modes, and second, an improved charge separation in the structured device arising due to perturbed built-in electric fields. Furthermore, the simulations which take into account the interfacial nano-scale morphology show that for absorbers with low carrier mobilities, a significant improvement in the photocurrent and in the fill factor is simultaneously possible. Overall, this work demonstrates a combination of tweaked bio-mimetic design and the use of unconventional robust structural materials as nanostructured optoelectronic substrates. This effort can bridge the gap between naturally evolved designs and practical optoelectronics to enhance the performance.


Subject(s)
Biomimetic Materials , Nanostructures , Optics and Photonics/instrumentation , Equipment Design
18.
J Thorac Oncol ; 12(10): 1512-1523, 2017 10.
Article in English | MEDLINE | ID: mdl-28634123

ABSTRACT

INTRODUCTION: Low-dose computed tomography screening for lung cancer has a high false-positive rate with frequent discovery of indeterminate pulmonary nodules. Noninvasive biomarkers are needed to reduce false positives and improve risk stratification. A retrospective longitudinal evaluation was performed to assess chromosomal aneusomy in sputum by fluorescence in situ hybridization (CA-FISH) in four nested case-control studies. METHODS: Receiver operating characteristic analysis resulted in two grouped cohorts: a high-risk cohort (Colorado High-Risk Cohort and Colorado Nodule Cohort [68 case patients and 69 controls]) and a screening cohort (American College of Radiology Imaging Network/National Lung Screening Trial and Pittsburgh Lung Screening Study [97 case patients and 185 controls]). The CA-FISH assay was a four-target DNA panel encompassing the EGFR and v-myc avian myelocytomatosis viral oncogene homolog (MYC) genes, and the 5p15 and centromere 6 regions or the fibroblast growth factor 1 gene (FGFR1) and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha gene (PIK3CA). A four-category scale (normal, probably normal, probably abnormal, and abnormal) was applied. Sensitivity, specificity, and positive and negative likelihood ratios (LRs) (with 95% confidence intervals [CIs]) were estimated for each cohort. RESULTS: Sensitivity and specificity were, respectively, 0.67 (95% CI: 0.55-0.78) and 0.94 (95% CI: 0.85-0.98) for high-risk participants and 0.20 (95% CI: 0.13-0.30) and 0.84 (95% CI: 0.78-0.89) for screening participants. The positive and negative LRs were, respectively, 11.66 (95% CI: 4.44-30.63) and 0.34 (95% CI: 0.24-0.48) for high-risk participants and 1.36 (95% CI: 0.81-2.28) and 0.93 (95% CI: 0.83-1.05) for screening participants. CONCLUSION: The high positive LR of sputum CA-FISH indicates that it could be a useful adjunct to low-dose computed tomography for lung cancer in high-risk settings. For screening, however, its low positive LR limits clinical utility. Prospective assessment of CA-FISH in the incidentally identified indeterminate nodule setting is ongoing in the Colorado Pulmonary Nodule Biomarker Trial.


Subject(s)
Lung Neoplasms/genetics , Aged , Chromosome Aberrations , Female , Humans , Lung Neoplasms/pathology , Male , Middle Aged , Risk Factors
19.
Eur Radiol ; 27(8): 3249-3256, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28050695

ABSTRACT

OBJECTIVES: This study retrospectively analyses the screening CT examinations and outcomes of the National Lung Screening Trial (NLST) participants who had interval lung cancer diagnosed within 1 year after a negative CT screen and before the next annual screen. METHODS: The screening CTs of all 44 participants diagnosed with interval lung cancer (cases) were matched with negative CT screens of participants who did not develop lung cancer (controls). A majority consensus process was used to classify each CT screen as positive or negative according to the NLST criteria and to estimate the likelihood that any abnormalities detected retrospectively were due to lung cancer. RESULTS: By retrospective review, 40/44 cases (91%) and 17/44 controls (39%) met the NLST criteria for a positive screen (P < 0.001). Cases had higher estimated likelihood of lung cancer (P < 0.001). Abnormalities included pulmonary nodules ≥4 mm (n = 16), mediastinal (n = 8) and hilar (n = 6) masses, and bronchial lesions (n = 6). Cancers were stage III or IV at diagnosis in 32/44 cases (73%); 37/44 patients (84%) died of lung cancer, compared to 225/649 (35%) for all screen-detected cancers (P < 0.0001). CONCLUSION: Most cases met the NLST criteria for a positive screen. Awareness of missed abnormalities and interpretation errors may aid lung cancer identification in CT screening. KEY POINTS: • Lung cancer within a year of a negative CT screen was rare. • Abnormalities likely due to lung cancer were identified retrospectively in most patients. • Awareness of error types may help identify lung cancer sooner.


Subject(s)
Early Detection of Cancer/standards , Lung Neoplasms/diagnostic imaging , Mass Screening/standards , Tomography, X-Ray Computed , Aged , Diagnostic Errors/prevention & control , Female , Humans , Male , Middle Aged , Multiple Pulmonary Nodules/diagnostic imaging , Retrospective Studies
20.
J Am Coll Radiol ; 13(12 Pt A): 1426-1432, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27916109

ABSTRACT

To meet challenges related to changing demographics, and to optimize the promise of diversity, radiologists must bridge the gap between numbers of women and historically underrepresented minorities in radiology and radiation oncology as contrasted with other medical specialties. Research reveals multiple ways that women and underrepresented minorities can benefit radiology education, research, and practice. To achieve those benefits, promising practices promote developing and implementing strategies that support diversity as an institutional priority and cultivate shared responsibility among all members to create inclusive learning and workplace environments. Strategies also include providing professional development to empower and equip members to accomplish diversity-related goals. Among topics for professional development about diversity, unconscious bias has shown positive results. Unconscious bias refers to ways humans unknowingly draw upon assumptions about individuals and groups to make decisions about them. Researchers have documented unconscious bias in a variety of contexts and professions, including health care, in which they have studied differential treatment, diagnosis, prescribed care, patient well-being and compliance, physician-patient interactions, clinical decision making, and medical school education. These studies demonstrate unfavorable impacts on members of underrepresented groups and women. Learning about and striving to counteract unconscious bias points to promising practices for increasing the numbers of women and underrepresented minorities in the radiology and radiation oncology workforce.


Subject(s)
Cultural Diversity , Physicians, Women/trends , Radiology Department, Hospital/organization & administration , Radiology , Sexism/trends , Sexual and Gender Minorities , Ethnicity , Health Personnel/trends , Health Workforce/trends , Humans , United States/ethnology
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