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Delamination between layers in photovoltaic (PV) backsheets is often reported in the literature, causing voids that can collect moisture, diminish module backside heat dissipation, and reduce the backsheet’s effectiveness as a physical barrier. While backsheets with weathering-resistant fluoropolymer outer layers have traditionally been used in modules, more recent backsheets using non-fluoropolymer outer layers, such as polyethylene terephthalate (PET), have been developed. These backsheets have shown signs of premature degradation, and their adhesion degradation, in particular, has not been widely studied. In the present work, the single cantilever beam (SCB) adhesion test was used to quantify the adhesion energy in two commercially available PET-based backsheets. To study the effect of minor changes in formulation, the backsheets were obtained from same manufacturer and product line but during different years. To study the effect of environmental variables on adhesion degradation, the backsheets were subjected to artificial weathering at controlled temperature, humidity, and ultraviolet (UV) radiation in an indoor weathering chamber, and the adhesion energy was quantified at several intervals of exposure time. Layering structure, composition, and adhesion failure mode were compared between the backsheets, using Raman and infrared spectroscopy and thermogravimetric analysis. The results show a large difference in initial (unexposed) adhesion energy between the backsheets, despite very similar structures and compositions. Following exposure, adhesion energy dropped significantly, primarily due to thermo-hydrolytic degradation of the polyurethane (PU)-based adhesive layers. Significant UV-induced adhesion degradation of the PET outer layer surface was also observed. The study represents an important step in understanding adhesion degradation in PET-based backsheets, suggesting ways in which adhesion integrity – and, correspondingly, module service life – can be improved.

Objective To determine rates of watchful waiting (WW) vs treatment in prostate cancer (PCa) and limited life expectancy (LE) and assess determinants of management. Materials and Methods Patients diagnosed with PCa between 2012 and 2018 with Results Total 2393 patients were included. Overall, WW was performed in 8.1% compared to 23.3%, 25%, 11.2%, and 3.6% who underwent AS, radiation (XRT), prostatectomy (RP), and brachytherapy (BT), respectively. In men with NCCN low-risk disease (n = 358), WW was performed in 15.1%, compared to AS (69.3%), XRT (4.2%), RP (6.7%), and BT (2.5%). There was wide variation in management among practices in low-risk men; WW (6%-35%), AS (44%-81%), and definitive treatment (0%-30%). Older age was associated with less likelihood of undergoing AS vs WW (odds ratio [OR] 0.88, P Conclusion Wide practice level variation exists in management for patients with low- and favorable-risk PCa and

Colorectal cancer screening has been shown to prevent or detect early colorectal cancer and reduce mortality; yet, adherence to screening recommendations remains low, particularly in rural settings.RCT.Adults (n=7,812) aged 50-75 years and due for colorectal cancer screening in a largely rural health system were randomly assigned to either the intervention (n=3,906) or the control (n=3,906) group in September 2016, with analysis following through 2018.A mailed motivational messaging screening reminder letter with an option to call and request a free at-home fecal immunochemical screening test (intervention) or the standard invitation letter detailing that the individual was due for screening (control). Multifaceted motivational messaging emphasized colorectal cancer preventability and the ease and affordability of screening, and communicated a limited supply of test kits.Colorectal cancer screening participation within 6 months after mailed invitation was ascertained from the electronic medical record.Colorectal cancer screening participation was significantly improved in the intervention (30.1%) vs the usual care control group (22.5%; p0.001). Individuals randomized to the intervention group had 49% higher odds of being screened over follow-up than those randomized to the control group (OR=1.49, 95% CI=1.34, 1.65). A total of 13.2 screening invitations were needed to accomplish 1 additional screening over the usual care. Of the 233 fecal immunochemical test kits mailed to participants, 154 (66.1%) were returned, and 18 (11.7%) tested positive.A mailed motivational messaging letter with a low-cost screening alternative increased colorectal cancer screening in this largely rural community with generally poor adherence to screening recommendations. Mailed colorectal cancer screening reminders using motivational messaging may be an effective method for increasing screening and reducing rural colorectal cancer disparities.

Several guidelines recommend pelvic lymph node dissection (PLND) at robot-assisted radical prostatectomy (RARP) only when lymph node involvement (LN+) is2%. Individual surgeon use of PLND is not well-known. We sought to examine variability in PLND performance and detection of LN+ across the Michigan Urological Surgery Improvement Collaborative.Data regarding all RARP (3/2012-9/2018) were prospectively collected, including patient and surgeon characteristics. Univariable and multivariable analyses of PLND rate and LN+ rate were performed.Among 9,751 men undergoing RARP, 79.8% had PLND performed (n = 7,781), of which 5.2% were LN+ (n = 404). In univariate and multivariable analyses, predictors of PLND included higher Prostate-Specific Antigen (PSA), biopsy Gleason grade (bGG), number of positive cores, and maximum core involvement at P0.05 for each. Higher PSA, cT stage, bGG, number of positive cores, and maximum core involvement predicted LN+ when PLND was performed (P0.05 for each). There was significant surgeon variation in the proportion of PLND performed at RARP, yet neither surgeon-annualized RARP volume nor % of PLND performed was associated with LN+ disease (P0.05). Grade was associated with PLND (60.0%, 77.6%, 91.0%, 97.3%, and 98.5%; P0.001) and LN+ (0.7%, 2.5%, 5.8%, 8.6%, and 19.9%; P0.001) for bGG 1,2,3,4,5, respectively. Maximum core involvement also strongly predicted LN+ with rates of 1.5%, 3.8%, and 9.4% for35%, 35% to 65%, and65%, respectively (P0.001).Nearly 80% of RARP in Michigan Urological Surgery Improvement Collaborative were performed with PLND, including 60% of bGG1 patients (with LN+ in only 0.7%), but significant variability exists between surgeons. Our data indicate limited benefit for favorable-risk CaP patients and support efforts to decrease PLND use going forward.

Perovskite materials are being considered for a variety of applications due to their demonstrated capacity to rapidly transport lattice oxygen. Importantly, controlling the dopant concentration in the perovskite lattice has been shown to tune the oxygen vacancy formation energy, an important descriptor for oxygen ion diffusivity. In this work, we utilize BaFe 1 − x InxO 3 − δ as a model perovskite for investigating the role that atomic-scale patterns of substitutional doping at the B site has on the formation of oxygen vacancies. Using this model material, we demonstrate a framework for evaluating the atomic-scale properties of possible dopant motifs exhibited within a doped perovskite lattice. For each relevant motif, we calculate via density functional theory the oxygen excess energy, which is a robust descriptor for evaluating the bulk oxide ion diffusion. We then formulate and solve a mathematical optimization model to identify patterns of dopant placement that yield materials with desirable properties. These results provide optimistic targets for material performance and may inform future material synthesis efforts.

Background Nearly 1.5 million clinicians in the United States will be affected by Centers for Medicare and Medicaid Services’ (CMS) new payment program, the Merit-based Incentive Program (MIPS), where clinicians will be penalized or rewarded based on the health care expenditures of their patients. We therefore examined expenditures for major cancer surgery to understand physician-specific variation in episode payments. Methods We used Surveillance, Epidemiology and End Results–Medicare data to identify patients aged 66–99 y who underwent a prostatectomy, nephrectomy, lung, or colorectal resection for cancer from 2008 to 2012. We calculated 90-d episode payments, attributed each episode to a physician, and evaluated physician-level payment variation. Next, we determined which component (index admission, readmission, physician services, postacute care, hospice) drove differences in payments. Finally, we evaluated payments by geographic region, number of comorbidities, and cancer stage. Results We identified 39,109 patients who underwent surgery by 1 of 7182 providers. There was wide variation in payments for each procedure (prostatectomy: $7046–$40,687; nephrectomy: $8855–$82,489; lung resection: $11,167–$223,467; colorectal resection: $9711–$199,480). The largest component difference in episode payments varied by condition: physician payments for prostatectomy (29%), postacute care for nephrectomy (38%) and colorectal resections (38%), and index hospital admission for lung resections (43%) but were fairly stable across region, comorbidity number, and cancer stage. Conclusions For patients undergoing major cancer surgery, 90-d episode payments vary widely across surgeons. The components driving such variation differ by condition but remain stable across region, number of comorbidities, and cancer stage. These data suggest that programs to reduce specific component payments may have advantages over those targeting individual physicians for decreasing health care expenditures.

The ability of designated electrically insulating materials in a module, including the backsheet, to act as insulators is a key safety requirement for photovoltaic technology. The recently developed test standards IEC TS 62788-2 (including a method for direct-current breakdown-voltage) and IEC TS 62788-7-2 (for ultraviolet [UV] weathering) are examined for the first time together in this study. Thirty-six contemporary backsheets were compared using the breakdown-voltage test, before and after UV weathering, according to the recent A3 test condition. Twenty-eight backsheets, extracted from a variety of veteran photovoltaic modules, were also examined using the breakdown test. Additional characterizations were performed to interpret the breakdown-voltage results, including: surface and cross-sectional optical microscopy failure analysis; cross-sectional scanning electron (SEM) microscopy with EDS energy-dispersive X-ray spectroscopy (EDX) failure analysis; Fourier-transform infrared spectroscopy (FTIR) to identify the base resin and its chemical integrity; and differential scanning calorimetry (DSC) to identify phase transitions that might adversely affect degradation during weathering. The electrical insulation for the backsheets is discussed relative to: the industry safety requirement; features observed to facilitate the degradation of insulation; the validity of the artificial UV weathering test; the validity of the sheet geometry used for specimens in this study; and the validity of subsequent mechanical testing.

We developed a framework to predict and model the photodegradation of adhesion and cohesion of a silicone encapsulant for concentrator photovoltaic applications. Silicone encapsulant specimens were artificially weathered under narrow band UV filters to determine the effects of individual wavelengths within the UV spectrum on the photodegradation of the cohesion of encapsulant material and its adhesion with adjacent interfaces. The threshold wavelength, signifying the upper bound of the damaging action spectrum for the silicone, was identified from the results. In addition, specimens were artificially weathered with different relative humidities to understand the effects of moisture on the rate of photodegradation. The adhesion energy was measured using a fracture mechanics approach. The complementary delaminated surfaces were characterized to determine the failure pathway and chemistry changes resulting from photodegradation. A previously developed model was modified to account for the effects of damaging wavelengths in the terrestrial solar spectrum and reciprocity law failure due to varying UV intensity during weathering. With these modifications, the model showed good agreement with the behavior of the silicone encapsulant exposed in an outdoor solar concentrator simulating concentrator photovoltaics operating conditions. Similar studies can be adopted to develop models that can have high predictive accuracies based on accelerated aging studies.

Background Intermediate clinical endpoints (ICEs) prognostic for overall survival (OS) are needed for men receiving postprostatectomy radiation therapy (PORT) to improve clinical trial design. Objective To identify a potential ICE for men receiving PORT. Design, setting, and participants We performed an institutional review board–approved multi-institutional retrospective study of 566 men consecutively treated with PORT at tertiary care centers from 1986 to 2013. The median follow-up was 8.2 yr. Outcome measurements and statistical analysis Biochemical failure (BF), distant metastases (DM), and castrate-resistant prostate cancer (CRPC) were evaluated for correlation with OS and assessed as time-dependent variables in a multivariable Cox proportional hazards model and in landmark analyses at 1, 3, 5, and 7 yr after PORT. Cross-validated concordance ( c ) indices were used to assess model discrimination. Results and limitations OS at 1, 3, 5, and 7 yr after PORT was 98%, 95%, 90%, and 82%, respectively. In a time-varying model controlling for clinical and pathologic variables, BF (hazard ratio [HR] 2.32, 95% confidence interval [CI] 1.45–3.71; p p p c index when adjusting for baseline covariates (0.78), with 5-yr DM also providing the greatest increase in discriminatory power over a model only including baseline covariates. These findings require validation in prospective randomized data. Conclusions While limited by the retrospective nature of the data, 5-yr DM is associated with lower OS following PORT, outperforming the prognostic capability of BF and CRPC at 1, 3, 5, or 7 yr after treatment. Confirmation of this ICE as a surrogate for OS is needed from randomized trial data so that it can be incorporated into future clinical trial design. Patient summary We assessed potential intermediate clinical endpoints prognostic for overall survival in a cohort of men receiving radiotherapy after prostatectomy. We identified the development of metastatic disease within 5 yr after treatment as the strongest predictor of overall survival.

The contamination of solar photovoltaic cover glass can significantly reduce the transmittance of light to the surface of the photovoltaic cell, reducing the module's power output. The solar industry has been developing antireflection (AR) and antisoiling (AS) surface coatings to enhance light transmittance and mitigate the impacts of soiling. Although uncoated glass has been field tested for decades, minimal data exist to demonstrate the durability of AR and AS coatings against abrasion and surface erosion, including from: natural weathering, airborne sand, and industry cleaning practices. Coupons 75 mm square of varying types have been field-deployed to gather long-term data on coating durability; the initial results are presented here after 1 year of outdoor exposure near Sacramento, California. Duplicate sets of coupons were cleaned monthly per four different cleaning practices. All coupons demonstrated inorganic soiling as well as microscale biological contamination, regardless of cleaning method. Additionally, full-sized, field-aged modules from other areas of the world presented with similar types of contamination as the field-aged coupons; micrographs and results from genomic sequencing of this contamination are included here. Optical microscopy, scanning electron microscopy, atomic force microscopy/energy-dispersive spectroscopy, surface roughness, transmittance, and surface energy analysis of representative specimens and cleaning practices are presented.

Objective To examine the relationship between the use and results of early confirmatory testing and persistence on active surveillance (AS). Methods We identified all men in the Michigan Urological Surgery Improvement Collaborative registry diagnosed with favorable-risk prostate cancer from June 2016 to June 2017. We next examined trends in the use of early confirmatory test(s), defined as repeat biopsy, prostate magnetic resonance imaging, or molecular classifiers obtained within 6 months of the initial cancer diagnosis, in patients with favorable-risk prostate cancer. We then compared the proportion of men remaining on AS 6 months after diagnosis according to reassuring vs nonreassuring results, also stratifying by age and Gleason score. Results Among 2529 patients, 32.7% underwent early confirmatory testing within 6 months of diagnosis. Its use increased from 25.4% in the second quarter of 2016 to 34.9% in the second quarter of 2017 (P = .025). Molecular classifiers were most frequently used (55%), followed by magnetic resonance imaging (34%) and repeat biopsy (11%). Sixty-four percent (n = 523) had a reassuring result. Rates of AS were higher for patients with early reassuring results; 82% remained on AS (n = 427) compared to 52% (n = 157) of those with nonreassuring results and 51% (n = 873) with no early confirmatory testing (P Conclusion Rates of AS are higher among men with early reassuring results, supporting the clinical utility of these tests. Nonetheless, high rates of AS among patients with nonreassuring results underscore the complexity of shared decision-making in this setting.

To evaluate the integration of 3T nonendorectal coil multiparametric prostate magnetic resonance imaging (mpMRI) at 2 high-volume practices that routinely use mpMRI in the setting of active surveillance.This was an institutional review board-approved, Health Insurance Portability and Accountability Act-compliant, and dual-institution retrospective cohort study. Subjects undergoing 3T mpMRI without endorectal coil at either study institution over a 13-month period (August 1, 2015-August 31, 2016) were selected based on predefined criteria: clinical T1/T2 Gleason 6 prostate cancer, prostate-specific antigen15 ng/mL, ≥40 years old, mpMRI within 2 years of prostate biopsy, and Prostate Imaging Reporting and Data System (PI-RADS) v2 score assigned. Subjects surveilled for Gleason ≥3 + 4 prostate cancer were excluded. The primary outcome was detection of Gleason ≥3 + 4 prostate cancer on magnetic resonance-ultrasound fusion biopsy, standard biopsy, or prostatectomy within 6 months following mpMRI. Positive predictive values (PPVs) were calculated.A total of 286 subjects (N = 193 from institution 1, N = 93 from institution 2) met the criteria. Most (87% [90 of 104]) with maximum PI-RADS v2 scores of 1-2 did not receive immediate biopsy or treatment and remained on active surveillance. Incidence and PPVs for PI-RADS v2 scores of ≥3 were the following: PI-RADS 3 (n = 57 [20%], PPV 21% [6 of 29]), PI-RADS 4 (n = 96 [34%], PPV 51% [39 of 77]), and PI-RADS 5 (n = 29 [13%], PPV 71% [20 of 28]). No Gleason ≥4 + 3 prostate cancer was identified for PI-RADS v2 scores of 1-3 (0 of 43 with histology). Following mpMRI and subsequent biopsy, 21% (61 of 286) of subjects were removed from active surveillance and underwent definitive therapy.The 3T nonendorectal coil mpMRI has been integrated into the care of patients on active surveillance and effectively stratifies risk of Gleason ≥3 + 4 prostate cancer in this population.

Objective To report on the establishment of a unified, electronic patient-reported outcome (PRO) infrastructure and pilot results from the first 5 practices enrolled in the web-based collection system developed by the Michigan Urological Surgery Improvement Collaborative. Materials and Methods Eligible patients were those undergoing radical prostatectomy of 5 academic and community practices. PRO was obtained using a validated 21-item web-based questionnaire, regarding urinary function, erection function, and sexual interest and satisfaction. Data were collected preoperatively, at 3 months, and 6 months postoperatively. Patients were provided a link via email to complete the surveys. Perioperative and PRO data were analyzed as reports for individual patients and summary performance reports for individual surgeons. Results Among 773 eligible patients, 688 (89%) were enrolled preoperatively. Survey completion rate was 88%, 84%, and 90% preoperatively, at 3 months, and 6 months. Electronic completion rates preoperatively, at 3 months, and 6 months were 70%, 70%, and 68%, respectively. Mean urinary function scores were 18.3, 14.3, and 16.6 (good function ≥ 17), whereas mean erection scores were 18.7, 7.3, and 9.1 (good erection score ≥ 22) before surgery, at 3 months, and 6 months. Variation was noted for erectile function among the practices. Conclusion Collection of electronic PRO via this unified, web-based format was successful and provided results that reflect expected recovery and identify opportunities for improvement. This will be extended to more practices statewide to improve outcomes after radical prostatectomy.

This paper provides a short review of the multitude of processes proposed for solvent-based and sorbent-based post-combustion CO 2 capture. (Membrane-based systems, another important technology for CO 2 capture is outside the scope of this review.) The majority of process configurations discussed in the open literature focus on reducing the energy penalty with little consideration of capital cost or operability — key factors for industrial implementation. This paper highlights advances in all three areas and identifies opportunities for future research.

The accurate characterization of the thermodynamic models of a reactive solvent-based CO 2 capture system is essential for adequately capturing system behavior in a process model. Moreover, uncertainty in these models can significantly affect simulation results, although it is often neglected. With this incentive, a model of thermodynamic properties, including vapor-liquid equilibrium (VLE), enthalpy, and solution chemistry, has been developed using a rigorous methodology for the aqueous monoethanolamine (MEA) system as a baseline. The final thermodynamic framework consists of both a deterministic and stochastic model. The deterministic model is developed by regressing parameters of the e-NRTL activity coefficient model in Aspen Plus® to VLE, heat capacity, and heat of absorption data while downselecting the model’s large parameter space through use of information-theoretic criteria. The stochastic model is developed through an uncertainty quantification (UQ) procedure, using the results of the deterministic regression to determine a prior parameter distribution. This prior distribution and the experimental VLE data are used to derive a posterior distribution through Bayesian inference, which is used to represent the final stochastic model. A reaction model in which the kinetics are written in terms of the reaction equilibrium constants, to ensure consistency with the thermodynamics model, is developed. These new thermodynamic and reaction models are incorporated into an existing MEA system process model from the open literature, and the prior and posterior parameter distributions are propagated through the models. This provides valuable insight into the extent to which uncertainty in thermodynamic models affects key process variables, including CO 2 capture efficiency and energy requirement for solvent regeneration.

This paper presents a comprehensive model of a post-combustion CO2 compression system that uses a multistage centrifugal compressor train to take the CO2-rich gas from the regenerator of a CO2 capture system and compress it to the supercritical conditions required for pipeline transport. The compression system model includes inter-stage coolers, flash vessels, glycol tower for water removal, and the CO2 inventory of the associated system. Both inline and integral gear compressors are designed using dimensionless numbers and appropriate design constraints. The steady-state integral gear compressor model is validated against industrial compressor performance data provided by a commercial CO2 compressor manufacturer. Its performance is also compared to the performance of an inline compressor model using a typical feed stream from a post-combustion CO2 capture process. Performance curves using dimensionless exit flow coefficient and isentropic head coefficient are used for simulating off-design performance of the integral gear compressor. To avoid surge during operation, a controller has been designed. Transients of key process variables in response to various disturbances have been studied.

Objective To review our clinical T1a renal mass active surveillance (AS) cohort to determine whether renal mass biopsy was associated with maintenance of AS. Materials and Methods From our prospectively maintained database we identified patients starting AS from June 2009 to December 2011 who had at least 5 months of radiologic follow-up, unless limited by unexpected death or delayed intervention. The primary outcome was delayed intervention. Clinical, radiologic, and pathologic variables were compared. We constructed Kaplan-Meier survival curves for maintenance of AS. Cox multivariable regression analysis was performed to assess predictors of delayed intervention. Results We identified 118 patients who met criteria for inclusion with a median radiologic follow-up of 29.5 months. The delayed intervention group had greater initial mass size and faster growth rate compared to those who continued AS. Rate of renal mass biopsy was similar between the 2 groups. In the multivariable analysis, size >2 cm (hazard ratio [HR] 3.65, 95% confidence interval [CI] 1.28-10.38, P = .015), growth rate (continuous by mm/year: HR 1.26, 95% CI 1.12-1.41, P P = .29), were associated with increased risk of delayed intervention. Time-to-event curves also showed that size was closely associated with delayed intervention whereas renal mass biopsy was not. Conclusion At our institution, growth rate and initial tumor size appear to be more influential than renal mass biopsy results in determining delayed intervention after a period of AS. Further analysis is required to determine the role of renal biopsy in the management of patients being considered for AS.

Concentrator photovoltaic (CPV) modules operate in extreme conditions, including enhanced solar flux, elevated operating temperature, and frequent thermal cycling. Coupled with active environmental species such as oxygen and moisture, the operating conditions pose a unique materials challenge for guaranteeing operational lifetimes of greater than 25 years. Specifically, the encapsulants used in the optical elements are susceptible to environmental degradation during operation. For example, the interfaces must remain in contact to prevent optical attenuation and thermal runaway. We developed fracture mechanics based metrologies to characterize the adhesion of the silicone encapsulant and its adjacent surfaces, as well as the cohesion of the encapsulant. Further, we studied the effects of weathering on adhesion using an outdoor concentrator operating in excess of 1100 times the AM1.5 direct irradiance and in indoor environmental chambers with broadband ultraviolet (UV) irradiation combined with controlled temperature and humidity. We observed a sharp initial increase in adhesion energy followed by a gradual decrease in adhesion as a result of both outdoor concentrator exposure and indoor UV weathering. We characterized changes in mechanical properties and chemical structures using XPS, FTIR, and DMA to understand the fundamental connection between mechanical strength and the degradation of the silicone encapsulant. We developed physics based models to explain the change in adhesion and to predict operational lifetimes of the materials and their interfaces.

Photovoltaic module degradation from a high system voltage is a prevalent degradation mode in the field, where the enabling degradation mechanisms are inherently dependent on the voltage bias polarity of the installed system. Here, the effects of positive bias on module performance are confirmed and the underlying chemical degradation processes are more thoroughly investigated to reveal different degradation pathways from those previously reported in negative bias studies. When cells are under +1000 V stress, crystalline silicon mini-modules with poly(ethylene-co-vinyl acetate) (EVA) encapsulant demonstrated a significant photocurrent loss due to EVA discoloration and delamination from increased chemical reactivity at the front-side EVA/cell metallization interface. Brown discoloration of the EVA encapsulant near the cell gridlines is linked to an electrochemical reaction at the Ag gridlines under hot and humid conditions (85 °C, 85% relative humidity). Chemical compositional analysis using X-ray photoelectron spectroscopy (XPS) confirmed that the discoloration is attributed to the formation of silver sulfide (Ag2S) and/or silver oxide (Ag2O) species at the EVA/Ag gridline interface. The subsequent migration of Ag ions from the cell gridlines into the bulk of the EVA was evident from XPS depth profiling and optical microscopy. However, the Ag signal was not detected at the EVA/glass interface, inferring limited ionic transport through the nominally 0.45 mm thick encapsulant. For the samples studied herein, the sulfur is believed by the process of elimination to come from the ambient air, diffusing into the module through the permeable polymer backsheet.

Dynamic reduced models (D-RMs) derived from rigorous models are highly desired for speeding up dynamic simulations. A useful software tool named D-RM Builder was developed to automatically generate data-driven D-RMs from high-fidelity dynamic models. It allows a user to configure input/output variables, sample input space and generate sequences of step changes, launch high-fidelity model simulations, fit simulation results to a D-RM, and finally visualize and validate the D-RM. The Decoupled A-B Net (DABNet) nonlinear system identification model was used as the main D-RM type and was enhanced to model nonlinear multiple input and multiple output dynamic systems with options for double-pole formulation to handle fast/slow time scales and pole value optimization. The D-RM Builder tool has been successfully used to generate D-RMs for a highly nonlinear pH neutralization reactor system and a two-time-scale bubbling fluidized bed adsorber-reactor for CO2 capture.

To compare the accuracies of renal mass biopsy (RMB) and R.E.N.A.L. nephrometry score (RNS) nomograms for predicting benign vs malignant disease, and low- vs high-risk renal tumors.We included 281 renal masses in 277 patients who had complete RNS, preoperative RMB, and final pathology from renal surgery for clinically localized renal tumors. RMB and final pathology were determined to be benign or malignant, and malignancies were classified as low-risk (Fuhrman grade I/II) or high-risk (Fuhrman grade III/IV) (benign included in low-risk group). Previously published RNS nomograms were used to determine probabilities of any cancer and high-risk cancer. The gamma statistic was used to assess strength of association between RMB or RNS with final pathology.Of the 281 masses, 13 (5%) and 268 (95%) were confirmed benign and malignant, respectively, and 155 (55%) and 126 (45%) were confirmed low-risk and high-risk, respectively, on final pathology. The areas under the curve of the RNS nomograms for benign vs malignant disease and for low-risk vs high-risk renal tumors were 0.56 and 0.64, respectively. Concordances for predicting benign vs malignant disease were 99% for RMB (P .01, gamma 0.99) and 29% for RNS nomogram (P = .16, gamma 0.38). Concordances for predicting low-risk vs high-risk renal tumors were 67% for RMB (P .01, gamma 0.97) and 61% for RNS nomogram (P .01, gamma 0.47), respectively.Although RNS nomograms are useful for discriminating between benign vs malignant renal masses, and low-risk vs high-risk renal tumors, they are outperformed by RMB.

We discuss the development of a new composite dual cantilever beam (cDCB) thin-film adhesion testing method, which enables the quantitative measurement of adhesion on the thin and fragile substrates used in multijunction photovoltaics. In particular, we address the adhesion of several 2- and 3-layer antireflective coating systems on multijunction cells. By varying interface chemistry and morphology through processing, we demonstrate the marked effects on adhesion and help to develop an understanding of how high adhesion can be achieved, as adhesion values ranging from 0.5 J/m2 to 10 J/m2 were measured. Damp heat (85 °C/85% RH) was used to invoke degradation of interfacial adhesion. We demonstrate that even with germanium substrates that fracture relatively easily, quantitative measurements of adhesion can be made at high test yield. The cDCB test is discussed as an important new methodology, which can be broadly applied to any system that makes use of thin, brittle, or otherwise fragile substrates.

To anticipate the effects of accountable care organizations (ACOs) on surgical care, we examined pre-enrollment utilization, outcomes, and costs of inpatient surgery among hospitals currently enrolled in Medicare ACOs vs nonenrolling facilities.Using the Nationwide Inpatient Sample (2007 to 2011), we compared patient and hospital characteristics, distributions of surgical specialty care, and the most common inpatient surgeries performed between ACO-enrolling and nonenrolling hospitals before implementation of Medicare ACOs. We used multivariable regression to compare pre-enrollment inpatient mortality, length of stay (LOS), and costs.Hospitals now participating in Medicare ACO programs were more frequently nonprofit (P.001) and teaching institutions (P = .01) that performed more specialty procedures (P.001). We observed no clinically meaningful pre-enrollment differences for inpatient mortality, prolonged length of stay, or costs for procedures performed at ACO-enrolling vs nonenrolling hospitals.Medicare ACO hospitals had pre-enrollment outcomes that were similar to nonparticipating facilities. Future studies will determine whether ACO participation yields differential changes in surgical quality or costs.

The design of an oxy-combustion system for CO 2 capture involves the integration of multiple devices including air separation unit, coal-fired boiler, steam turbine, flue gas cleanup, recycle, and compression units. Thousands of design parameters for the entire system need to be optimized to achieve the lowest cost per kilowatt-hour of electricity generated. An appropriate first-principles based boiler model with short computer execution time but yet reasonable accuracy in both air-fired and oxy-fired configurations is highly desired. To this end, a hybrid boiler model with 1-D resolution for main flow and reaction related calculations and 3-D resolution for radiative heat transfer was developed as a part of the oxy-combustion subtask of the Carbon Capture and Simulation Initiative (CCSI) sponsored by U.S. Department of Energy. The developed model is able to automatically generate a 3-D mesh based on user-specified furnace shape for the calculation of radiative heat transfer using discrete ordinates method. The 3-D cells are assigned to individual regions along the furnace height, forming 1-D zones in which conservations of mass and energy in both gas and particle phases are enforced. The kinetics of heterogeneous reactions between char particles and gas reactants are modeled zone by zone in Lagrangian framework. Gas phase chemistry in each zone is simplified based on chemical equilibrium. The submodels for calculating the radiative properties of the gas and particle phases and those for calculating the heterogeneous char reactions are suitable for both air-fired and oxy-fired conditions. A typical boiler model can be converged in approximately 1 min on a personal computer and, therefore, is suitable for the generation of reduced order models in algebraic form which could be used for the large-scale multivariable optimization of the oxy-combustion systems. By modeling a utility boiler in both air-fired and oxy-fired configurations and comparing the results to those from computational fluid dynamics simulations, the hybrid boiler model was found to give very comparable predictions in major boiler performance parameters such as furnace exit gas temperature, heat losses to walls, and unburned carbon in fly ash. By modeling a small test furnace, it was found that with the adjustments on a “mixedness” related effectiveness factor for the char combustion and gasification reactions, the boiler model is able to correctly predict the trends of incident radiation heat flux profile along the furnace axial length as well as the trend of the unburned carbon in both air-fired and oxy-fired configurations.

This work focuses on development of a “gold standard” process model for a MEA-based post-combustion CO2 capture process. The steady-state model includes a comprehensive thermodynamic framework in conjunction with the chemistry model. Parameters for all thermodynamic, transport, and physical properties models are regressed using extensive data available in the literature. An integrated mass transfer model is developed and validated using experimental data. The steady-state model is validated using data collected from the U.S. DOE’s National Carbon Capture Center (NCCC) in Wilsonville, Alabama. In addition to the steady-state runs, dynamic test runs were conducted at NCCC by introducing carefully-designed step changes and recording the transients of all key variables. Due to measurement noise and missing measurements for a number of key variables, a dynamic data reconciliation problem was solved to ensure material and energy balance of the collected data. Both the steady-state and dynamic models were validated against plant data for a wide range of operating conditions.

The mechanical properties of four different families of ordered porous graphene or giant Schwarzites, up to 12,288 atoms per cubic cell, were studied theoretically in order to shed light on the properties of newly synthesized graphene-like foams. It is shown that as the Schwarzite grows in size, the structure becomes flatter and not only more energetically stable, but also more elastically stable, thus opening the possibility of being synthesized in the near future. The mechanical properties such as bulk modulus, Young's modulus, and Poisson's ratio have been calculated with first principles for the smaller cells and with empirical methods for the larger cells. The bulk and Young moduli decrease as the structures grow. The “P” and the “I-WP” geometries favor smaller values of Poisson's ratio, likely to be synthesized experimentally. For the larger gyroid “G” and “D” cases, elastic instabilities appear, and these can be alleviated by breaking the symmetry of the associated space group. In addition, ripples in the graphene sheet stabilize the giant “D” family as the crystal cell dimensions increase. Finally, based on density functional theory calculations, the electronic properties of the high genus I-WP were examined for the first time finding semiconducting, semimetallic, and metallic behaviors.

Objective To examine the magnitude and sources of inpatient cost variation for kidney transplantation. Methods We used the 2005-2009 Nationwide Inpatient Sample to identify patients who underwent kidney transplantation. We first calculated the patient-level cost of each transplantation admission and then aggregated costs to the hospital level. We fit hierarchical linear regression models to identify sources of cost variation and to estimate how much unexplained variation remained after adjusting for case-mix variables commonly found in administrative datasets. Results We identified 8866 living donor (LDRT) and 5589 deceased donor (DDRT) renal transplantations. We found that higher costs were associated with the presence of complications (LDRT, 14%; P

Solid sorbent-based CO 2 capture from flue gas provides a novel alternative to traditional solvent-based processes due to potentially lower energy consumption for regeneration. Optimal operation of such a gas-solid flow process requires an advanced control framework for efficient disturbance rejection and setpoint tracking. This work focuses on the development of computationally fast and accurate dynamic reduced models (D-RMs) and the application of these models to nonlinear model predictive control (NMPC) algorithms. Two different types of D-RMs are developed: the first type is a data-driven model where step-test data are utilized to generate the D-RM through the Decoupled A-B Net (DABNet) model, and the second type of D-RM is a temporal and spatial reduction of the original process model to improve its computational efficiency while still retaining its physics. Disturbance rejection and setpoint tracking characteristics of the NMPC and its computational performance are studied for both types of D-RMs. In addition, performance of both NMPC formulations are compared with linear model predictive control (LMPC) formulations.

In this paper, a methodology is developed for sequential design of experiments (SDoE) for process systems and applied to a solvent-based CO2 capture system. In this approach, the prior knowledge of the system is used to prioritize process data collection at specific operating conditions. These data are then incorporated into a Bayesian inference methodology for updating a stochastic model by refining estimations of its underlying parameters, and the updated model is then used to generate the next set of test runs. Thus, the new knowledge obtained from the data is used to guide subsequent iterations of the experimental runs, ensuring that the overall data collection is maximally informative given that most experimental campaigns, especially at pilot or higher-scale plants, are costly, time-consuming, and resource-limited. The test run objective for this work was to minimize the maximum model prediction uncertainty for key output variables, but the methodology is generic and can be readily applied to other test run objectives. This methodology is applied to an aqueous monoethanolamine (MEA) pilot plant campaign at the National Carbon Capture Center (NCCC) in Wilsonville, Alabama, USA. The SDoE framework was utilized for two iterations, while collecting 18 sets of data representing different process conditions, and this resulted in an overall average reduction in uncertainty of approximately 50% in the prediction of CO2 capture percentage. Moreover, 11 additional data sets were obtained with variation of absorber packing height for further model validation. This work shows the capability of the SDoE framework to maximize learning given limited resources, allowing for the reduction of model uncertainty, which is of great importance for many applications including reduction of technical risk associated with scale-up and economic analysis.

Determining the minimum number of units is an important step in heat exchanger network synthesis (HENS). The MILP transshipment model ( Papoulias and Grossmann, 1983 ) and transportation model ( Cerda and Westerberg, 1983 ) were developed for this purpose. However, they are computationally expensive when solving for large-scale problems. Several approaches are studied in this paper to enable the fast solution of large-scale MILP transshipment models. Model reformulation techniques are developed for tighter formulations with reduced LP relaxation gaps. Solution strategies are also proposed for improving the efficiency of the branch and bound method. Both approaches aim at finding the exact global optimal solution with reduced solution times. Several approximation approaches are also developed for finding good approximate solutions in relatively short times. Case study results show that the MILP transshipment model can be solved for relatively large-scale problems in reasonable times by applying the approaches proposed in this paper.

Objective To determine how well demographic and clinical factors predict the initiation of Active Surveillance (AS). Methods AS has been suggested as a way to reduce overtreatment of men who have prostate cancer; however, factors associated with the decision to choose AS are poorly quantified. Using the Michigan Urological Surgery Improvement Collaborative registry, we identified 2977 men with prostate cancer who made treatment decisions from January 1, 2012, through December 31, 2013. We used chi-square and Wilcoxon tests to examine the association between factors and initiation of AS. Logistic regression models were fit for D'Amico risk categories. Measures of model discrimination and calibration were estimated, including area under the curve (AUC) and Brier score (BS). Results Patient age, Gleason score, clinical T-stage, urology practice, and tumor volume (greatest percent of a core involved with cancer and proportion of positive cores) were associated with the decision to choose AS in the intermediate-risk cohort (AUC = 0.875, BS = 0.07) and the complete cohort (AUC = 0.89, BS = 0.10). Patient age, urology practice, and tumor volume were significant in the low-risk cohort (AUC = 0.71, BS = 0.22). The addition of urology practice increased AUC in the low-risk cohort from 0.71 to 0.76 and reduced BS from 0.22 to 0.21. Conclusion The urology practice at which a patient is seen is an important predictor for whether patients will initiate AS. Predictions were least accurate for low-risk patients, suggesting that factors such as patient preference play a role in treatment decisions.

This paper introduces a simultaneous process optimization and heat integration approach, which can be used directly with the rigorous models in process simulators. In this approach, the overall process is optimized utilizing external derivative-free optimizers, which interact directly with the process simulation. The heat integration subproblem is formulated as an LP model and solved simultaneously during optimization of the flowsheet to update the minimum utility and heat exchanger area targets. A piecewise linear approximation for the composite curve is applied to obtain more accurate heat integration results. This paper describes the application of this simultaneous approach for three cases: a recycle process, a separation process and a power plant with carbon capture. Case study results indicate that this simultaneous approach is relatively easy to implement and achieves higher profit and lower operating cost and, in the case of the power plant example, higher net efficiency than the sequential approach.

We address a central theme of empirical model building: the incorporation of first-principles information in a data-driven model-building process. By enabling modelers to leverage all available information, regression models can be constructed using measured data along with theory-driven knowledge of response variable bounds, thermodynamic limitations, boundary conditions, and other aspects of system knowledge. We expand the inclusion of regression constraints beyond intra-parameter relationships to relationships between combinations of predictors and response variables. Since the functional form of these constraints is more intuitive, they can be used to reveal hidden relationships between regression parameters that are not directly available to the modeler. First, we describe classes of a priori modeling constraints. Next, we propose a semi-infinite programming approach for the incorporation of these novel constraints. Finally, we detail several application areas and provide extensive computational results.

Active surveillance (AS) has been proposed as an effective strategy to reduce overtreatment among men with lower risk prostate cancers. However, historical rates of initial surveillance are low (4-20%), and little is known about its application among community-based urology practices.To describe contemporary utilization of AS among a population-based sample of men with low-risk prostate cancer.We performed a prospective cohort study of men with low-risk prostate cancer managed by urologists participating in the Michigan Urological Surgery Improvement Collaborative (MUSIC).The principal outcome was receipt of AS as initial management for low-risk prostate cancer including the frequency of follow-up prostate-specific antigen (PSA) testing, prostate biopsy, and local therapy. We examined variation in the use of surveillance according to patient characteristics and across MUSIC practices. Finally, we used claims data to validate treatment classification in the MUSIC registry.We identified 682 low-risk patients from 17 MUSIC practices. Overall, 49% of men underwent initial AS. Use of initial surveillance varied widely across practices (27-80%; p=0.005), even after accounting for differences in patient characteristics. Among men undergoing initial surveillance with at least 12 mo of follow-up, PSA testing was common (85%), whereas repeat biopsy was performed in only one-third of patients. There was excellent agreement between treatment assignments in the MUSIC registry and claims data (κ=0.93). Limitations include unknown treatment for 8% of men with low-risk cancer.Half of men in Michigan with low-risk prostate cancer receive initial AS. Because this proportion is much higher than reported previously, our findings suggest growing acceptance of this strategy for reducing overtreatment.We examined the use of initial active surveillance for the management of men with low-risk prostate cancer across the state of Michigan. We found that initial surveillance is used much more commonly than previously reported, but the likelihood of a patient being placed on surveillance depends strongly on where he is treated.

To identify clinical variables associated with a positive computed tomography (CT) scan and estimate the performance of imaging recommendations in patients from a diverse sample of urology practices.This study comprised 2380 men with newly diagnosed prostate cancer seen at 28 practices in the Michigan Urological Surgery Improvement Collaborative from March 2012 through September 2013. Data included age, prostate-specific antigen (PSA) level, Gleason score (GS), clinical T stage, total number of positive biopsy cores, whether or not the patient received a staging abdominal and/or pelvic CT scan, and CT scan result. We fit a multivariate logistic regression model to identify clinical variables associated with metastases detected by CT scan. We estimated the sensitivity and specificity of existing imaging recommendations.Among 643 men (27.4%) who underwent a staging CT scan, 62 men (9.6%) had a positive study. In the multivariate analysis, PSA, GS, and clinical T stage were independently associated with the occurrence of a positive CT scan (all P values.05). The American Urological Association's Best Practice Statements' recommendations for imaging when PSA level20 ng/mL or GS ≥ 8 or locally advanced cancer had a sensitivity of 87.3% and specificity of 82.6%. Compared with current practice, implementing this recommendation in the Michigan Urological Surgery Improvement Collaborative population was estimated to result in approximately 0.5% of positive study results being missed, and 26.1% of fewer study results overall.Successful implementation of CT imaging criterion of PSA level20, GS ≥ 8, or clinical stage ≥ T3 would ensure that CT scans are performed for almost all men who would have positive study results while reducing the number of negative study results.

To evaluate the performance of published guidelines compared with that of current practice for radiographic staging of men with newly diagnosed prostate cancer.Using data from the Michigan Urological Surgery Improvement Collaborative clinical registry, we identified 1509 men diagnosed with prostate cancer from March 2012 through June 2013. Clinical data included age, prostate-specific antigen (PSA) level, Gleason score (GS), clinical trial stage, number of biopsy cores, and bone scan (BS) results. We then fit a multivariate logistic regression model to examine the association between clinical variables and the occurrence of bone metastases. Because some patients did not undergo BS, we used established methods to correct for verification bias and estimate the diagnostic accuracy of published guidelines.Among 416 men who received a BS, 48 (11.5%) had evidence of bone metastases. Patients with bone metastases were older, with higher PSA levels and GS (all P.05). In multivariate analyses, PSA (P.001) and GS (P = .004) were the only independent predictors of positive BS. Guidelines from the American Urological Association and the National Comprehensive Cancer Network demonstrated similar performance in detecting bone metastases in our population, with fewer negative study results than those of the European Association of Urology guideline. Applying the American Urological Association recommendations (ie, image when PSA level20 ng/mL or GS ≥ 8) to current clinical practice, we estimate that1% of positive study results would be missed, whereas the number of negative study results would be reduced by 38%.Based on current practice patterns, more uniform application of existing guidelines would ensure that BS is performed for almost all men with bone metastases, while avoiding many negative imaging studies.

Objective To present the benefits and utility of tumor enucleation as an alternative technique to sharp excision during minimally invasive partial nephrectomy (MIPN). Methods We retrospectively compared enucleation and sharp excision during MIPN, with the aim of determining benefits and limitations of enucleation in this setting. Results Among 602 patients undergoing MIPN at our institution, 86 and 516 underwent enucleation and sharp excision, respectively, as determined by the surgeon. The nephrometry score was greater in the enucleation vs sharp excision group (mean, 6.7 vs 6.3), but all other preoperative parameters were similar. The mean ischemia and operative times were 4 and 32 minutes shorter in the enucleation group, respectively, likely owing to less frequent entry into renal sinus (21% vs 41%) and need for tumor bed suturing (41% vs 62%), compared with those in the sharp excision group. There was no association with blood loss, positive margins, urine leak, blood transfusion, major complications, renal function, recurrence, or survival. Conclusion Enucleation appears to provide the benefits of reduced surgical entry into the renal sinus, less need for tumor bed suturing, and shorter operative time, without any impact on functional or oncologic outcomes. Given favorable preoperative radiography and intraoperative findings, enucleation is a useful technique for patients undergoing MIPN.