Search

Graphical abstract The breakdown voltage of some contemporary backsheets was reduced by ∼50% after UV weathering (a). The intermediate performance for unaged backsheet with the EVA layer removed identifies that degradation has occurred in the PET core layer. A red circle identifies a crack observed in EVA layer on the sun side in cross-section images of the backsheet immediately after weathering (b). The clean removal of the EVA layer using xylenes is verified for unaged backsheet in (c). Highlights • The DC breakdown voltage >8 kV suggests a margin for electrical insulation and thickness exists. • Artificial UV weathering reduced the breakdown voltage of 6/36 contemporary backsheets by >20%. • The breakdown voltage of 26/28 legacy backsheet materials extracted from veteran modules is >8 kV. • The artificial weathering of sheet specimens was found to result in unrepresentative damage. Abstract 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. [ABSTRACT FROM AUTHOR]

Abstract 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. Highlights • Silicone based encapsulant degrades and embrittles from solar exposure. • Threshold wavelength for causing UV degradation of silicone encapsulant is 350 nm. • Adhesion energy drops by over 2 orders of magnitude following degradation. • Adhesion energy can be modeled as a function of temperature and solar irradiance. [ABSTRACT FROM AUTHOR]

The optical performance of poly(methyl methacrylate) lenses from veteran concentrator photovoltaic modules was examined after the end of their service life. Lenses from the Martin-Marietta and Intersol module designs were examined from the “Solar Village” site near Riyadh, Saudi Arabia, as well as the Phoenix Sky Harbor airport, followed by the Arizona Public Service Solar Test and Research (APS-STaR) center in Tempe, Arizona. The various lens specimens were deployed for 20, 27, and 22 years, respectively. Optical characterizations included lens efficiency (Solar Simulator instrument), material transmittance and haze (of coupons cut from veteran lenses, then measured again after their faceted back surface was polished, and then measured again after the incident front surface was polished), and direct transmittance (as a function of detector's acceptance angle, using the Very Low Angular Beam Spread (“VLABS”) instrument). Lens efficiency measurements compared the central region to the entire lens, also using hot and cold mirror measurements to diagnose differences in performance. A series of subsequent characterizations was performed because a decrease in performance of greater than 10% was observed for some of the veteran lenses. The optimal focal distance of the lenses was quantified using the Solar Simulator, and then correlated to lens curvature using a recently developed measurement technique. Surface roughness was examined using atomic force microscopy and scanning electron microscopy. Facet geometry (tip and valley radius) was quantified on cross-sectioned specimens. Molecular weight was compared between the incident and faceted surfaces of the lenses. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive model of a post-combustion CO 2 compression system that uses a multistage centrifugal compressor train to take the CO 2 -rich gas from the regenerator of a CO 2 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 CO 2 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 CO 2 compressor manufacturer. Its performance is also compared to the performance of an inline compressor model using a typical feed stream from a post-combustion CO 2 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Because surgical skill may be a key determinant of patient outcomes, there is growing interest in skill assessment. In the Michigan Urological Surgery Improvement Collaborative (MUSIC), we assessed whether peer and crowd-sourced (ie, layperson) video review of robot-assisted radical prostatectomy (RARP) could distinguish technical skill among practicing surgeons. A total of 76 video clips from 12 MUSIC surgeons consisted of one of four parts of RARP and underwent blinded review by MUSIC peer surgeons and prequalified crowd-sourced reviewers. Videos were rated for global skill (Global Evaluation Assessment of Robotic Skills) and procedure-specific skill (Robotic Anastomosis and Competency Evaluation). We fit linear mixed-effects models to estimate mean peer and crowd ratings for each video. Individual video ratings were aggregated to calculate surgeon skill scores. Peers ( n = 25) completed 351 video ratings over 15 d, whereas crowd-sourced reviewers ( n = 680) completed 2990 video ratings in 38 h. Surgeon global skill scores ranged from 15.8 to 21.7 (peer) and from 19.2 to 20.9 (crowd). Peer and crowd ratings demonstrated strong correlation for both global ( r = 0.78) and anastomosis ( r = 0.74) skills. The two groups consistently agreed on the rank order of lower scoring surgeons, suggesting a potential role for crowd-sourced methodology in the assessment of surgical performance. Lack of patient outcomes is a limitation and forms the basis of future study. Patient summary We demonstrated the large-scale feasibility of assessing the technical skill of robotic surgeons and found that online crowd-sourced reviewers agreed with experts on the rank order of surgeons with the lowest technical skill scores. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract: The Affordable Care Act seeks to overhaul the US health care system by providing insurance for more Americans, improving the quality of health care delivery, and reducing health care expenditures. Although the law's intent is clear, its implementation and effect on patient care remains largely undefined. Herein, we discuss major components of the Affordable Care Act, including the proposed insurance expansion, payment and delivery system reforms (e.g., bundled payments and Accountable Care Organizations), and other reforms relevant to the field of urologic oncology. We also discuss how these proposed reforms may affect patients with urologic cancers. [Copyright &y& Elsevier]

Abstract: The backsheets used in photovoltaic modules are exposed to aggressive field environments that may include combined temperature cycles, moisture, and mechanical loads. The effects of the field environment on backsheet debonding, which can lead to module degradation (corrosion) and loss of function, are still not well understood or quantified. Employing a newly developed quantitative mechanics technique, we report the effect of aging on backsheet debond energy, including the separate effect of temperature, mechanical stress and relative humidity on debond growth rate. The debond energy of the backsheet decreased dramatically from 1000 to 27J/m2 within the first 750h of exposure to hot (85°C) and humid (85% RH) aging treatments. The debond growth rate increased up to 500-fold with small changes of temperature (10°C) and relative humidity (20%). To elucidate the mechanisms of environmental debonding, we developed a fracture-kinetics model, where the molecular relaxation processes at the debond front are used to predict debond growth. The model and techniques form the fundamental basis to develop accelerated aging tests and long-term reliability predictions for photovoltaic backsheets. [Copyright &y& Elsevier]

Highlights: [•] The post-combustion CO2 capture performances of three amine solvents were compared. [•] DEA has potential for lower energy penalty and capital cost than 11mol% MEA and AMP. [•] There are tradeoffs in capital cost and energy penalty in CO2 capture processes. [Copyright &y& Elsevier]

Abstract: The degradation of poly(methyl methacrylate) (PMMA) exposed to ultra-violet (UV) light, heat, and humidity is examined using a variety of materials characterization techniques. Using contemporary material formulations, some of which are specifically marketed to the PV industry, techniques were identified that can readily discern material changes in PMMA degraded by artificial weathering. Separate PMMA formulations were categorized as “hazy” or “yellow”, based on their visual appearance after 18 cumulative months of indoor aging in an environmental chamber equipped with a xenon-arc lamp. The characteristics examined included: optical transmittance (and the corresponding yellowness index); surface roughness (examined via atomic force and scanning electron microscopy); surface chemistry (via X-ray photoelectron spectroscopy); elastic modulus and mechanical hardness (via nanoindentation); thermal decomposition (via thermogravimetric analysis); bulk chemistry (via nuclear magnetic resonance); molecular weight (via gel permeation chromatography); and optical fluorescence. The comparison between the most affected “hazy” and “yellow” specimens illustrates some of the ways these measurement techniques can be used to explore changes in application-critical characteristics and mechanisms involved in material degradation. [Copyright &y& Elsevier]

Abstract: Objectives: We assessed the influence of tumor size and surgical approach on the use of lymphadenectomy and adrenalectomy with radical nephrectomy. Methods: We evaluated patients with renal cell carcinoma (RCC) enrolled in the U.S. Kidney Cancer Study, a case-control study in the metropolitan areas of Detroit and Chicago from 2002 to 2007. We identified patients who underwent open (ORN) or laparoscopic radical nephrectomy (LRN). We used medical records and Surveillance, Epidemiology, and End Results (SEER) data to determine the proportion of patients who underwent lymphadenectomy or adrenalectomy. Bivariate analyses were performed to evaluate associations between tumor size, surgical approach, and receipt of lymphadenectomy or adrenalectomy. Results: We identified 730 patients who underwent ORN (427, 58%) or LRN (303, 42%) for RCC from 2002 to 2007. Among this group, 11% and 24% underwent lymphadenectomy or adrenalectomy, respectively. Lymphadenectomy was more common among patients treated from an open surgical approach (14.1% ORN vs. 5.9% LRN, P < 0.01); this difference was most pronounced for cases with tumors between 4 and 7 cm (15.9% vs. 2.9%, P = 0.01). Patients treated with ORN were also more likely to undergo adrenalectomy, with the greatest discrepancy among cases with tumors ≤ 4 cm (21.7% vs. 11.4%, P < 0.01). Conclusions: Among patients undergoing radical nephrectomy for RCC, the use of lymphadenectomy and adrenalectomy is relatively uncommon and varies by tumor size and surgical approach. With an increasing number of patients with small tumors, the diffusion of laparoscopy, and the emergence of clinical trials evaluating systemic adjuvant therapies, our findings highlight important considerations for optimizing surgical management of patients with RCC. [Copyright &y& Elsevier]

Abstract: The long term sustainability of fossil energy systems depends on reducing their carbon footprint and freshwater consumption. Much of the United States is or will be experiencing water shortages in the near future. Since power generation accounts for about a third of all freshwater use, reducing freshwater requirements will be of increasing importance. In addition, recent reports indicate that adding a carbon capture system may double water consumption. Thus, when designing a carbon capture and compression system, it is important to consider not only the direct costs, but also the increased environmental burden associated with increased freshwater requirements. To address these interrelated sustainability issues, a modular framework for multi-objective analysis was developed and demonstrated by minimizing freshwater consumption and levelized cost of electricity for the retrofit of a hypothetical 550 MW subcritical pulverized coal power plant with an MEA-based carbon capture and compression system. [Copyright &y& Elsevier]

Abstract: The durability of Fresnel lenses used in the concentrating photovoltaic (CPV) application is reviewed from the literature. The examination here primarily concerns monolithic lenses constructed of poly(methyl methacrylate) (PMMA), with supplemental examination of silicone-on-glass (SOG) composite lenses. For PMMA, the review includes the topics of: optical durability (loss of transmittance with age); discoloration (the wavelength-specific loss of transmittance); microcrazing and hazing; fracture and mechanical fatigue; physical aging, creep, shape change, buckling, and warping; and solid erosion. Soiling, or the accumulation of particulate matter, is examined in the following contexts: its magnitude of reduction in transmittance; variation with time, module tilt, and wavelength; the processes of adhesion and accumulation; particle size, distribution, composition, and morphology; and its prevention. Photodegradation and thermal decomposition, mechanisms enabling aging, are examined relative to the CPV-specific environment. Aspects specific to SOG lenses include: solarization of the glass superstrate; corrosion of glass; delamination of the silicone/glass interface; change in focus due to thermal misfit between the laminate layers; and the chemical stability of poly(dimethylsiloxane) (PDMS). Recommendations for future research are provided, based on the most important and the least explored topics. [Copyright &y& Elsevier]

Abstract: A significant number of efforts are underway to develop and assess technologies that will lead to technically and economically viable routes to reduce the CO2 emissions of fossil energy systems, particularly coal-fired power plants. Developing technologies to reduce emissions from these sources is essential for controlling atmospheric levels of CO2 because of the widespread reliance on coal as an inexpensive and abundant energy source. Two major systems-level design challenges exist. The first is how to design new plants that incorporate CCS technology. The second is how to retrofit existing plants to capture CO2. Both design challenges can benefit from an optimization approach, which considers the application of multiple potential technologies and analyzes ways in which the whole plant-wide system can be integrated to increase overall efficiency. This paper will present a modular framework for the analysis and optimization of power generation systems with CCS that helps to meet these design challenges. In order to more completely understand the economic and operational tradeoffs associated with the various potential carbon capture technologies, and how they can be applied to new and existing plants, a unified, systemic framework has been developed to provide a common basis for evaluation. Given the complexity of the design problem and the fact that new technologies are continually being developed, this framework is modular in nature and incorporates algorithms for the selection, integration and optimization of carbon capture technologies for both new and existing plants. In addition to the framework itself, this paper discusses simulation modules representing various capture technologies and power plant components. The framework provides the means to link the various modules together in order to provide a holistic, systems perspective of plant wide operations. Results of analyses and optimization scenarios performed with the framework are also presented. [Copyright &y& Elsevier]

Abstract: Nanometer-scale-thick, polymer-like coatings deposited using the molecular layer deposition (MLD) technique constitute a new class of materials. The modulus and hardness of aluminum alkoxide (“alucone”) films grown using either homobifunctional or heterobifunctional reactants were measured using nanoindentation. Because the coatings are brittle and possess a significant tensile film stress immediately after deposition, the influence of film stress on the indentation measurements was quantified using a numerical analysis protocol. The film stress and coefficient of thermal expansion for alucone were determined using the wafer curvature method. Film stress was found to stabilize within the first thermal cycle, demonstrating a repeatable hysteresis thereafter. Curvature/time measurements on coated microcantilever beams indicated that the most significant evolution in film stress for alucone occurred during the initial 2weeks of storage in the ambient environment. The temporal behavior is attributed to the change in thickness and/or modulus of alucone, and is consistent with the film stress becoming more compressive over time. An encapsulating alumina film, coated using the atomic layer deposition technique, was found to suppress the evolution of stress within alucone. The studies here suggest that the alucones have a greater elastic modulus than traditional polymers, are at present quite brittle and are prone to environmental influence. The MLD technique, however, possesses a rich wealth of options that enable the modulus, adhesion and chemical stability of the coatings to be tailored. [Copyright &y& Elsevier]

Abstract: Previously-documented variations in patterns of care and patient outcomes suggest differences in the quality of care provided to men with prostate cancer. Herein we describe ongoing efforts to measure the quality of prostate cancer care, including the development and pilot-testing of the RAND prostate cancer quality indicators and the selection of the consensus-based Physician Performance Measurement Set for Prostate Cancer. We also summarize current payer-led initiatives aimed at measuring quality of care for men with prostate cancer. We conclude that currently-available prostate cancer quality indicators are derived from valid, consensus-based methodologies and capture clinical practices that are necessary for high-quality care in early-stage prostate cancer. Despite this promise, however, the currently available measures have several limitations that should be considered during their implementation in prostate cancer quality assessment and improvement activities. [Copyright &y& Elsevier]

Abstract: Design of microelectromechanical systems (MEMS) requires an understanding of the material characteristics inherent to the specific processing technologies. In this study, several design-critical characteristics of a silicon-on-insulator (SOI) MEMS fabrication technology (SOIMUMPs) have been examined and compared to a surface micromachined MEMS fabrication technology (polyMUMPs), both produced by MEMSCAP, Inc. Diagnostic structures were utilized to evaluate material characteristics including: minimum achievable feature size, deviation of feature size from nominal design dimensions, through-thickness residual strain gradient, in-plane residual strain, resistivity, surface roughness, and fracture strength. In general, most of the measured characteristics were similar for SOIMUMPs and polyMUMPs, in spite of their very different fundamental process constraints. For example, the characteristic fracture strength was 1.97 and 1.43GPa, with associated Weibull moduli of 8.9 and 14.0, respectively. These values are similar given the very different sources of silicon: mechanically thinned single crystal silicon wafers versus low-pressure chemical vapor deposition for polycrystalline films. Fractography suggests that fracture strength for the both technologies is controlled by surface topography features: individual sidewall etching defects drive SOIMUMPs failures whereas top-surface grain boundary crevices drive polyMUMPs failures. Discussion focuses on the ramifications of the process-controlled material characteristics in SOIMUMPS and polyMUMPs to the design of MEMS components. [Copyright &y& Elsevier]

Objectives: To evaluate the penetrance of the new pathologic standard of care, we characterized the temporal trends in histologic subtype-specific kidney cancer incidence rates. Molecular genetics have refined our understanding of kidney cancer, such that kidney cancer is now recognized as a family of tumors with distinct molecular and clinical characteristics. The histologic classification of kidney cancer has been revised to reflect this new paradigm. Methods: Using the Surveillance, Epidemiology, and End Results Program, we identified incident cases from 1983 to 2002. Tumor histologic types were assigned, using the International Classification of Disease-Oncology codes. The histologic-specific incidence rates were calculated and directly age-adjusted to the 2000 U.S. population. Results: The histologic type was available for 40,813 cases. Subsequent to the Heidelberg consensus conference, the rate of papillary histologic types rose appropriately from 0.02 in 1998 to 0.89 in 2002 per 100,000 U.S. population, and the incidence of granular cell histologic types remained relatively stable (0.22 to 0.14 cases per 100,000), despite its exclusion as a unique histologic subtype. Paradoxically, the incidence of chromophobe tumors decreased during this interval (0.03 to 0.003 cases per 100,000). Conclusions: Following the publication of the Heidelberg classification scheme, we have described the differential changes in incidence rates for newly described histologic variants. Our results suggest incomplete penetration of these guidelines. The continued reporting of granular cell histologic types is particularly noteworthy, given that it is no longer recognized as a distinct histologic subtype. Proper categorization of the histologic subtype (eg, chromophobe, papillary, clear cell) is imperative, because it may confer useful information regarding the prognosis, response to adjuvant treatment, and eligibility for clinical trials. [Copyright &y& Elsevier]

Abstract: Objectives: The detection of postoperative complications is a necessary quality-of-care endeavor. Despite its historical role, the Morbidity and Mortality (M&M) Conference depends on voluntary reporting and may be an insufficient mechanism for comprehensive complication surveillance. In response to this concern, we compared the concordance between complications voluntarily reported at the M&M Conference and those identified prospectively by the National Surgical Quality Improvement Program (NSQIP). Methods: For a single calendar year (2004), we compiled a comprehensive list of complications that were either identified and voluntarily entered into our department’s electronic M&M Conference database and/or identified prospectively (from an explicit sample of cases) by a trained research associate-based NSQIP protocol. For analytic purposes, we treated NSQIP as the reference standard for the detection of complications. We then determined the sensitivity of the M&M Conference for the identification of complications at a patient and event level. Logistic regression modeling was used to evaluate for an association between complication category (ie, organ system affected) and detection by the M&M Conference. Results: The NSQIP detected 347 complications in 176 patients. Using this reference standard, the patient-level and event-level sensitivity of the M&M Conference was 25% (44 of 176) and 14% (47 of 347), respectively. The sensitivity of the M&M Conference varied by NSQIP complication category (P = 0.08). Circulatory events were 11 times more likely to be reported at the M&M Conference than urinary complications (odds ratio 11.3, 95% confidence interval 2.4 to 53.7). Conclusions: Compared with the NSQIP, the M&M Conference has a low (but variable) sensitivity for the detection of postoperative complications. Therefore, despite its limitations, the NSQIP may provide a better foundation for urologic quality improvement endeavors. [Copyright &y& Elsevier]

Abstract: Objectives: To evaluate the potential association between sexual motivation and patterns of erectile dysfunction (ED) therapy among a large cohort of localized prostate cancer treatment survivors. Methods: The use of medications and devices to improve erections and sexual health-related quality of life (HRQOL) were evaluated using a mailed Expanded Prostate Cancer Index Composite survey administered to 896 men 4 to 8 years after brachytherapy, three-dimensional conformal external beam radiotherapy (3D-CRT), or radical prostatectomy and 112 control men. The responding participants (73% of those surveyed) were classified by prostate cancer treatment, sexual motivation, and ED therapy use. Bivariate and multivariate analyses were used to identify the factors associated with ED therapy use and sexual HRQOL outcome. Results: The quality of erections unassisted by medications or devices was not different among the treatment groups. Prostate cancer survivors used medications or devices for ED more commonly than did the control men (30% versus 13%; P <0.01). One half of the prostate cancer survivors with ED reported indifference regarding their ED (small to no sexual bother despite absent or poor unassisted erections). Conversely, among men who were bothered by poor erections, 48% of the brachytherapy, 61% of the 3D-CRT, and 23% of radical prostatectomy subjects had never tried commonly available medications or devices to improve their erections (P <0.01). The current use of at least one erection aid was an independent determinant of more favorable sexual HRQOL (P <0.01). Conclusions: Many men who are bothered by posttreatment ED reported never having tried medications or devices to improve their erections. The lack of ED therapy was more prevalent among patients with erectile concerns after brachytherapy or 3D-CRT than after radical prostatectomy, suggesting possible opportunities for improving sexual HRQOL among long-term survivors. [Copyright &y& Elsevier]

Abstract: Objectives: To address the concern that laparoscopic radical nephrectomy (LRN) is being applied in cases of small renal masses in which nephron-sparing surgery (NSS) might be more appropriate. Methods: From 1998 to 2003, 381 consecutive patients underwent 391 procedures at our institution for renal cell carcinoma, of which 336 were for organ-confined tumors. The temporal trends in the application of LRN and NSS were assessed relative to the clinical stage. Results: During the transition from early (1998 to 2000) to late (2001 to 2003) experience with laparoscopy, the use of LRN among patients with Stage T1a (4 cm or smaller) lesions remained infrequent (21% and 20%, respectively). In contrast, LRN increased among patients with larger lesions during this same interval (Stage T1b, 36% versus 56%, P = 0.017 and Stage T2, 24% versus 41%, P = 0.056). Concurrently, the use of NSS (open surgical or laparoscopic partial nephrectomy) increased for both Stage T1a (25% and 31% versus 34% and 37%, P = 0.082) and T1b (8% and 6% versus 19% and 5%, P = 0.017) tumors. Multivariate analysis demonstrated that the use of both NSS and LRN increased significantly with time (P = 0.002 and P = 0.001, respectively). Neither NSS nor LRN were associated with a greater risk of perioperative complications relative to radical or open surgery (P >0.05 for both). Conclusions: During a 6-year period at our institution, most Stage T1a lesions were managed with NSS, and a significant increase occurred in the use of NSS for Stage T1b tumors, despite the concurrent increasing application of LRN. These findings suggest that oncologic, rather than technologic, concerns were determining our practice patterns. [Copyright &y& Elsevier]

Abstract: Au/Cr/Si microcantilevers were studied in their as-deposited condition and annealed state, with emphasis on a thermal treatment of 225°C for 24h. Change in beam curvature was monitored during isothermal hold as a function of time. Secondary grain growth was observed in the gold, which contained non-uniformly distributed twins and dislocation defects. Diffusional transport of the chromium layer was observed during annealing. Nodules arranged in a “rolling hill” topography were observed at the free surface, both before and after annealing. Nanometer thick coatings of alumina grown by atomic layer deposition improved the uniformity of both microstructure evolution and curvature evolution during high-temperature annealing. [Copyright &y& Elsevier]

Abstract: Introduction: Discrepancies between clinical and pathologic staging, herein referred to as stage divergence, are common after radical cystectomy. The implications of stage divergence on survival are ill defined in the context of those treated by surgery alone and would facilitate patient counseling and enhance prognostication. Methods: There were 78 consecutive radical cystectomy patients with clinical stage T2 or less urothelial carcinoma who comprised our study population. Kaplan-Meier plots were constructed to determine the effects of stage divergence on survival and the log-rank test employed to assess the significance. Regression models were developed to determine predictors of overall and cancer-specific survival. Results: Stage divergence was common after radical cystectomy with downstaging and upstaging occurring in 27% and 49% of patients, respectively. Downstaged patients had better overall (P = 0.003) and bladder cancer-specific (P = 0.0004) survivals. None of the downstaged patient died from bladder cancer (median follow-up 35.9 months). Upstaged patients were five times as likely to succumb from bladder cancer or other illness compared to downstaged patients. This effect was not isolated to patients with lower clinical stages but also demonstrated in patients with clinical stage T2 bladder cancer. Conclusions: Stage divergence is common after radical cystectomy occurring in 76% of patients in this study. The implications of stage divergence are equally relevant for those who are upstaged or downstaged in terms of survival, and such data is useful when counseling patients postoperatively. Downstaging at the time of radical cystectomy is associated with better overall and cancer-specific survival. [Copyright &y& Elsevier]

Objectives: To examine the impact of various treatment modalities on survival among patients with bladder cancer who were 80 years old or older compared with younger patients. A compendium of evidence suggests that bladder cancer surgery is safe among octogenarians; however, the benefit of such treatment in a population with limited life expectancy has not been well documented.Methods: Subjects with the primary diagnosis of bladder cancer were identified from the National Cancer Institute''s Surveillance, Epidemiology, and End Results cancer registry between 1988 and 1999. Of the 13,796 patients diagnosed with bladder cancer, 24% were older than 80 years of age. Proportional hazards regression modeling was performed to determine the independent association of treatment strategy on overall and bladder cancer survival while adjusting for multiple covariates.Results: Of patients 80 years old or older, bladder cancer management included watchful waiting (7%), radiotherapy alone (1%), full or partial cystectomy (12%), and transurethral resection (79%). Patients 80 years old or older were less likely to be treated with extirpative surgery than their younger counterparts (P <0.0001). Cox proportional hazards models demonstrated that, among patients 80 years old or older, radical cystectomy/partial cystectomy had the greatest risk reduction in death from bladder cancer (hazard ratio 0.3) and death from any cause (hazard ratio 0.4) among the primary treatment modalities (both P <0.0001).Conclusions: Disparities in practice patterns between younger and geriatric patients with bladder cancer exist. We provide compelling evidence that aggressive surgical management of bladder cancer in these patients may improve survival. Risk adjustment tools should be used to identify patients (young and old) who would be better served by less aggressive management. [Copyright &y& Elsevier]

Objectives: To evaluate the volume-outcome relationship in patients undergoing nephrectomy for neoplastic disease by examining the impact of the number of cases performed on in-hospital mortality and length of stay. Surgical volume is associated with postoperative mortality for many complex procedures; however, this relationship has not been characterized for patients undergoing nephrectomy for neoplastic disease.Methods: Using the Nationwide Inpatient Sample database, 20,765 patients who underwent nephrectomy for neoplasm from 1993 through 1997 were identified by International Classification of Disease, Ninth Revision codes. Cases were stratified into volume groups on the basis of annual nephrectomy rates: low-volume hospitals performed 1 to 14 nephrectomies per year, medium-volume hospitals performed 15 to 33 per year, and high-volume hospitals performed more than 33 per year. Unadjusted and risk-adjusted analyses were performed.Results: Overall mortality was 1.39%. Mortality declined as surgical volume increased. The mortality rate for low-volume hospitals was 1.60% versus 1.49% for medium-volume hospitals and 1.04% for high-volume hospitals (P = 0.017). After adjusting for case mix, high-volume hospitals had a 32% lower risk of in-hospital mortality than medium-volume hospitals (P = 0.029) and a 25% lower risk than low-volume hospitals (P = 0.094). Length of stay was not affected by hospital volume. Other independent risk factors for in-hospital mortality included age older than 65 years, chronic pulmonary disease, metastatic disease, and the urgent nature of the admission.Conclusions: A greater surgical volume, age younger than 65 years, elective conditions, and less comorbidity are associated with a significantly decreased risk of in-hospital mortality after nephrectomy. These findings provide compelling evidence that hospital volume and patient characteristics have important effects on surgical outcome specific to renal neoplasms. [Copyright &y& Elsevier]

: ObjectivesTo describe a percutaneous approach that uses laparoscopic techniques and technology to achieve intact removal of bladder stones after augmentation cystoplasty.: MethodsPercutaneous stone removal using a laparoscopic entrapment sac was performed in 4 patients with augmented bladders. Under endoscopic guidance, a 10-mm laparoscopic trocar was placed percutaneously into the augmented bladder using the previous suprapubic tube site. The stones were then maneuvered into a laparoscopic entrapment sac and extracted intact without lithotripsy.: ResultsPercutaneous removal of the entire stone burden (up to seven stones in 1 patient) was achieved in 3 of 4 patients. The total operative time was less than 1 hour in each of these cases. Partial conversion to open cystolithotomy was required in 1 patient, because of tearing of the entrapment sac. Three of 4 cases were performed on an outpatient basis and less than 24 hours of catheter drainage was required in all but 1 patient.: ConclusionsPercutaneous cystolithotomy using a laparoscopic entrapment sac is a safe, useful, and minimally invasive modification of contemporary percutaneous techniques. In patients with augmented bladders, application of this technique may minimize the risk of residual fragments and obviate the need for adjuvant lithotripsy. [Copyright &y& Elsevier]

Objectives: To determine the impact of processed total motile sperm (PTMS) count on pregnancy after partner intrauterine insemination (IUI). IUI is generally attempted before proceeding to more expensive and invasive assisted-reproductive techniques such as intracytoplasmic sperm injection. Several semen parameters have been shown to correlate with IUI outcome and may be useful when counseling couples.Methods: Four hundred thirty-eight couples with diverse causes of infertility underwent 1114 cycles of husband IUI during a 39-month period. The clinical and semen parameters were recorded for each couple and each insemination. The parameters were compared between those couples who achieved a pregnancy and those who did not.Results: The total number of pregnancies was 120, resulting in a pregnancy rate per cycle of 10.8% and a couple pregnancy rate of 27.4%. On multivariable logistic regression analysis, the PTMS count was independently associated with fertility after IUI (P = 0.0014). Moreover, the pregnancy rate was significantly lower for couples with less than 10 million PTMS (P <0.05).Conclusions: The results of this study have demonstrated that the PTMS count independently predicts success with IUI. Cycles with less than 10 million total motile sperm are significantly less likely to result in a pregnancy. If cause-specific therapy has failed, alternatives to IUI should be considered for couples when the PTMS count is less than 10 million. [ABSTRACT FROM AUTHOR]

The ability of electrical insulating materials within a module to act as insulators is a key safety requirement for photovoltaic (PV) technology. Presently, however, the durability of backsheets may not be readily assessed. For example, the mechanical tensile test continues to be developed, and its use has not been validated such that a technically based pass/fail criteria may be established. This study examines the use of simple indentation methods, including durometer hardness and instrumented indentation, as a means to quantitively assess the degradation of PV backsheets. Characteristics including: hardness, modulus, load/displacement profile, creep hold response, and residual impression are explored in an empirical study. Glass/encapsulant/backsheet mini-modules constructed using backsheets including: polyamide (specifically the AAA backsheet product), poly(ethylene terephthalate) (PET), polyvinyl fluoride (PVF) laminate ("TPE"), and polyvinylidene fluoride (PVDF) were examined. An M-type durometer as well as Berkovich and cube-corner tips were used in the indentation experiments. Additional characterizations were performed to interpret the indentation measurements including: surface roughness measurements using atomic force microscopy (AFM), a chemical structure study using Fourier-transform infrared spectroscopy (FTIR), and phase-transition measurements using differential scanning calorimetry (DSC). The results are analyzed in the context of the combined accelerated stress test (C-AST) also explored in this study. Instrumented indentation (i.e., using a Berkovich tip) was able to distinguish between backsheets and quantify the effects of accelerated testing (including up to 60%, 25%, and 20% change in hardness, modulus, and creep displacement, respectively). The embrittlement of the backsheets was not readily assessable using cube-corner indentation. Cracking of the known-bad polyamide backsheet was observed from the C-AST, which was not observed to result from steady state UV weathering. Image 1 • Instrumented indentation (i.e., using a Berkovich tip) readily distinguished the mechanical responce of unaged backsheets. • Instrumented indentation readily distinguished the effects of accelerated stress testing, e.g., in a reliability study. • The fracture toughness of the backsheets could not be determined from the cracks at the corners of the indent impression. • The combined accelerated stress test (C-AST) in this study was able to cause cracking in known-bad AAA backsheet. [ABSTRACT FROM AUTHOR]

Presents a guide to the professional literature on publishing. 'Encyclopedia of Information Systems and Services,' 9th edition, by Amy Lucas; 'The Road to CD-ROM'; 'Multiple Use of Primary Full Text Information--A Publisher's Perspective,' by David P. Martinsen.

Abstract: The administration of local anesthesia both topical and injectable before transrectal ultrasound-guided prostate biopsy is safe and efficacious. We describe our technique and review the relevant published data on this topic. [Copyright &y& Elsevier]

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. [ABSTRACT FROM AUTHOR]