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A parametric study of a solid oxide fuel cell-gas turbine (SOFC-GT) hybrid system design is conducted with the intention of determining the thermodynamically based design space constrained by modern material and operating limits. The analysis is performed using a thermodynamic model of a generalized SOFC-GT system where the sizing of all components, except the fuel cell, is allowed to vary. Effects of parameters such as pressure ratio, fuel utilization, oxygen utilization, and current density are examined. Operational limits are discussed in terms of maximum combustor exit temperature, maximum heat exchanger effectiveness, limiting current density, maximum hydrogen utilization, and fuel cell temperature rise. It was found that the maximum hydrogen utilization and combustor exit temperature were the most significant constraints on the system design space. The design space includes the use of cathode flow recycling and air preheating via a recuperator (heat exchanger). The effect on system efficiency of exhaust gas recirculation using an ejector versus using a blower is discussed, while both are compared with the base case of using a heat exchanger only. It was found that use of an ejector for exhaust gas recirculation caused the highest efficiency loss, and the base case was found to exhibit the highest overall system efficiency. The use of a cathode recycle blower allowed the largest downsizing of the heat exchanger, although avoiding cathode recycling altogether achieved the highest efficiency. Efficiencies in the range of 50-75% were found for variations in pressure ratio, fuel utilization, oxygen utilization, and current density. The best performing systems that fell within all design constraints were those that used a heat exchanger only to preheat air, moderate pressure ratios, low oxygen utilizations, and high fuel utilizations. Copyright © 2010 by ASME.

A 100 MW-class planar solid oxide fuel cell synchronous gas turbine hybrid system has been designed, modeled, and controlled. The system is built of 70 functional fuel cell modules, each containing 10 fuel cell stacks, a blower to recirculate depleted cathode air, a depleted fuel oxidizer, and a cathode inlet air recuperator with bypass. The recuperator bypass serves to control the cathode inlet air temperature, while the variable speed cathode blower recirculates air to control the cathode air inlet temperature. This allows for excellent fuel cell thermal management without independent control of the gas turbine, which at this scale will most likely be a synchronous generator. In concept the demonstrated modular design makes it possible to vary the number of cells controlled by each fuel valve, power electronics module, and recirculation blower, so that actuators can adjust to variations in the hundreds of thousands of fuel cells contained within the 100 MW hybrid system for improved control and reliability. In addition, the modular design makes it possible to take individual fuel cell modules offline for maintenance while the overall system continues to operate. Parametric steady-state design analyses conducted on the system reveal that the overall fuel-to-electricity conversion efficiency of the current system increases with increased cathode exhaust recirculation. To evaluate and demonstrate the conceptualized design, the fully integrated system was modeled dynamically in MATLAB-SIMULINK. Simple proportional feedback with steady-state feed-forward controls for power tracking, thermal management, and stable gas turbine operation were developed for the system. Simulations of the fully controlled system indicate that the system has a high efficiency over a large range of operating conditions, decent transient load following capability, fuel and ambient temperature disturbance rejection, and the capability to operate with a varying number of fuel cell modules. The efforts here build on prior work and combine the efforts of system design, system operation, component performance characterization, and control to demonstrate hybrid transient capability in large-scale coal synthesis gas-based applications through simulation. Furthermore, the use of a modular fuel cell system design, the use of blower recirculation, and the need for integrated system controls are verified. © 2010 by ASME.

The article focuses on the case of a 74-year-old woman who complained to her physician of increasing lethargy and dyspnoea and undergone an examination which revealed a macroglossia with submandibular swelling, a regular bradycardia of 40 beats per minute and a bilateral pitting oedema.

Introduction: Single-station N2 (ssN2) versus multi-station N2 has been used as a selection criterion for treatment recommendations between surgical versus non-surgical multimodality treatment in stage III-N2 NSCLC. We hypothesized that clinical staging would be susceptible to upstaging on pathologic staging and, therefore, challenge this practice., Methods: A retrospective study of prospectively collected routine clinical data for patients with stage III-N2 NSCLC that had completed computed tomography (CT), positron emission tomography (PET), and staging endobronchial ultrasound (EBUS) and had been confirmed clinical stage III-ssN2 at multidisciplinary team discussion and went on to complete surgical resection as the first treatment to provide pathologic staging. The study was completed in two cohorts (A) across a single cancer alliance in England (Greater Manchester) January 1, 2015 to December 31, 2018 and (B) across five United Kingdom centers to validate the findings in part A January 1, 2016 to December 31, 2020., Results: A total of 115 patients met the inclusion criteria across cohort A (56 patients) and cohort B (59 patients) across 15 United Kingdom hospitals. The proportion of cases in which clinical stage III-ssN2 was upstaged to pathologic stage III-multi-station N2 was 34% (19 of 56) in cohort A, 32% in cohort B (19 of 59), and 33% across the combined study cohort (38 of 115). Most patients had a single radiologically abnormal lymph node on CT and PET (88%, 105 of 115). In the majority, the reasons for missed N2 disease on staging EBUS were due to inaccessible (stations 5, 6, 8, 9) N2 nodes at EBUS (34%, 13 of 38) and accessible lymph nodes not sampled during staging EBUS as not meeting sampling threshold (40%, 15 of 38) rather than false-negative sampling during EBUS (26%, 10 of 38)., Conclusions: During multidisciplinary team discussions, clinicians must be aware that one-third of patients with stage III-ssN2 on the basis of CT, PET, and staging EBUS do not truly have ssN2 and this questions the use of this criterion to define treatment recommendations., Competing Interests: The authors declare no conflict of interest., (© 2024 The Authors.)

Background: COPD patients have varying degrees of airways disease and emphysema. CT scanning can differentiate these pathological subtypes. We evaluated airway dimensions and emphysema severity with low dose CT scanning in COPD patients to determine relationships with clinical features of the disease., Methods: Fifty six patients with COPD had a low dose thoracic CT scan. Airways were analysed using novel software as either proximal (1st and 2nd generation) or distal (3rd to 6th generation); the extent of emphysema was assessed as the percentage of pixels less than -950 Hounsfield units. CT measures were related to clinical features of COPD., Results: Thicker walls in the proximal airways were associated with clinical features that may represent a bronchitic phenotype (MRC Bronchitis Score; β = 0.20, p = 0.003, Frequent Exacerbations; β = 0.14, p = 0.017, Total St George's Score; β = 0.50, p = 0.001 and body mass index [BMI]; β = 0.26, p = 0.049); these associations were independent of emphysema. BMI was negatively correlated with the degree of emphysema (β = -0.41, p = 0.001). Airway wall thickness was negatively correlated with CT measured emphysema for both proximal and more distal airways (r = -0.30, p = 0.025 and r = -0.32, p = 0.015)., Conclusions: CT measured airway dimensions are associated with several clinical measures of COPD; these are related to a bronchitic phenotype and the effect is independent of emphysema., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Computed tomography (CT) scanning allows precise assessment of both the extent and distribution of emphysema. There has been little work on the relationship between the distribution of emphysema and clinical features of the disease. The current study investigated the association between clinical features and distribution of emphysema. A total of 129 patients with smoking-related chronic obstructive pulmonary disease underwent CT assessment of the extent and distribution of their emphysema (core/rind and upper/lower zone predominance). Emphysema was found predominantly in the upper/core zone and this distribution was related to the extent of disease. Core predominance was associated with lower forced expiratory volume in one second (FEV(1)), FEV(1)/forced vital capacity ratio and body mass index (BMI); and with higher BODE (BMI, airflow obstruction, dyspnoea and exercise capacity) index and Medical Research Council dyspnoea score. Upper-zone predominance was associated with female sex and an increased total St George's Respiratory Questionnaire score. Using multiple linear regression age, sex and whole lung emphysema severity were independently associated with core/rind distribution, while sex and whole lung emphysema severity were independently related to upper/lower distribution. Distribution of emphysema related best to clinical features when divided into core/rind predominance. However, the effects were not independent of the extent of emphysema. Increased age and female sex were related to disease distribution independent of emphysema severity. These findings may be related to differences in development of emphysema.

The expression of insulin-like growth factor 2 (IGF2) and insulin-like growth factor binding protein 2 (IGFBP2) in 11 cases of hepatoblastoma was studied by means of in situ mRNA hybridization using digoxigenin (DIG)-labeled riboprobes. The results showed that both IGF2 and IGFBP2 transcripts are present in hepatoblastoma and that their expression is inversely correlated with the degree of tumor cell differentiation. The data suggested that IGF2 and IGFBP2 gene expression could be regarded as a marker for assessment of the degree of differentiation in hepatoblastoma.

The present studies examined the pathogenesis of focal glomerular sclerosis in aging rats. A marked difference in development of the lesion was noted between males and females, and strain variability was an important factor. Increased glomerular basement membrane permeability with loss of selectivity unrelated to changes in glomerular sialoprotein occurred with aging and was accompanied by increasing proteinuria. Noncomplement-fixing mesangial deposits of rat IgM were present after 1 month of age and were also found in lesser amounts in germfree rats. Fluoresceinated eluates of rat kidneys did not have antibody activity against rat serum or tissue antigens. There was no evidence for a pathogenetic role of IgM deposits. Rat IgG, IgA, IgE, C3, and fibrin were occasionally found in sclerotic areas. Analysis of multiple histologic sections revealed a close correlation between aging and glomerular pathology, with a poor correlation between tubular damage and aging. Glomerular damage appeared to be the initial event leading to tubular damage. Indirect evidence suggests that a relative thymic deficiency may play an important role in the pathogenesis of the lesion.

Modeling is a means of formulating and testing complex hypotheses. Useful modeling is now possible with biological laboratory microcomputers with which experimenters feel comfortable. Artificial intelligence (AI) is sufficiently similar to modeling that AI techniques, now becoming usable on microcomputers, are applicable to modeling. Microcomputer and AI applications to physiological system studies with multienzyme models and with kinetic models of isolated enzymes are described. Using an IBM PC microcomputer, we have been able to fit kinetic enzyme models; to extend this process to design kinetic experiments by determining the optimal conditions; and to construct an enzyme (hexokinase) kinetics data base. We have also used a PC to do most of the constructing of complex multienzyme models, initially with small simple BASIC programs; alternative methods with standard spreadsheet or data base programs have been defined. Formulating and solving differential equations in appropriate representational languages, and sensitivity analysis, are soon likely to be feasible with PCs. Much of the modeling process can be stated in terms of AI expert systems, using sets of rules for fitting and evaluating models and designing further experiments. AI techniques also permit critiquing and evaluating the data, experiments, and hypotheses being modeled, and can be extended to supervise the calculations involved.