Chemical approaches to artificial photosynthesis Concepcion, Javier J.; House, Ralph L.; Papanikolas, John M. ...
Proceedings of the National Academy of Sciences - PNAS,
09/2012, Letnik:
109, Številka:
39
Journal Article
Background Accurate preoperative diagnosis and staging of cholangiocarcinoma (CCA) remain difficult. Objective To evaluate the utility of EUS in the diagnosis and preoperative evaluation of CCA. ...Design Observational study of prospectively collected data. Setting Single tertiary referral hospital in Indianapolis, Indiana. Patients Consecutive patients with CCA from January 2003 through October 2009. Interventions EUS and EUS-guided FNA (EUS-FNA). Main Outcome Measurements Sensitivity of EUS for the detection of a tumor and prediction of unresectability compared with CT and magnetic resonance imaging (MRI); sensitivity of EUS-FNA to provide tissue diagnosis, by using surgical pathology as a reference standard. Results A total of 228 patients with biliary strictures undergoing EUS were identified. Of these, 81 (mean age 70 years, 45 men) had CCA. Fifty-one patients (63%) had distal and 30 (37%) had proximal CCA. For those with available imaging, tumor detection was superior with EUS compared with triphasic CT (76 of 81 94% vs 23 of 75 30%, respectively; P < .001). MRI identified the tumor in 11 of 26 patients (42%; P = .07 vs EUS). EUS identified CCA in all 51 (100%) distal and 25 (83%) of 30 proximal tumors ( P < .01). EUS-FNA (median, 5 passes; range, 1-12 passes) was performed in 74 patients (91%). The overall sensitivity of EUS-FNA for the diagnosis of CCA was 73% (95% confidence interval, 62%-82%) and was significantly higher in distal compared with proximal CCA (81% vs 59%, respectively; P = .04). Fifteen tumors were definitely unresectable. EUS correctly identified unresectability in 8 of 15 and correctly identified the 38 of 39 patients with resectable tumors (53% sensitivity and 97% specificity for unresectability). CT and/or MRI failed to detect unresectability in 6 of these 8 patients. Limitation Single-center study. Conclusion EUS and EUS-FNA are sensitive for the diagnosis of CCA and very specific in predicting unresectability. The sensitivity of EUS-FNA is significantly higher in distal than in proximal CCA.
Locally advanced pancreatic cancer (LAPC) has a poor prognosis. There are limited data describing the use of photodynamic therapy (PDT) for pancreatic cancer in humans. We hypothesized that ...EUS-guided PDT for LAPC is safe, technically feasible, and produces a dose- and time-dependent increasing degree of image-defined tumor necrosis.
In a single-center, prospective, dose-escalation phase 1 study, patients with treatment-naïve LAPC received intravenous porfimer sodium (Concordia Laboratories Inc, St Michael, Barbados) followed 2 days later by EUS-PDT. EUS-PDT was performed by puncture with a 19-gauge needle and insertion of a 1.0-cm light diffuser (Pioneer Optics, Bloomfield, Conn) and illumination with a 630-nm light (Diomed Inc, Andover, Mass). A CT scan 18 days after PDT was done to assess for change in pancreatic necrosis. Nab-paclitaxel (125 mg/ m2 intravenously) and gemcitabine (1000 mg /m2 intravenously) were initiated 7 days after CT and given weekly for 3 of 4 weeks (1 cycle) until disease progression or unacceptable toxicity.
Twelve patients (mean age, 67 ± 6 years; 8 male) with tumors (mean diameter, 45.2 ± 12.9 mm) in the head and/or neck (8) or body and/or tail (4) underwent EUS-PDT. Compared with baseline imaging, increased volume and percentage of tumor necrosis were observed in 6 of 12 patients (50%) after EUS-PDT. The mean overall increases in volume and percentage necrosis were 10 ± 26 cm3 (P = .20) and 18% ± 22% (P = .016), respectively. After a median follow-up of 10.5 months (range, 1.0-37.4 months), median progression-free (PFS) and overall survival (OS) were 2.6 months (95% confidence interval, 0.7, not estimable) and 11.5 months (95% confidence interval, 1.1, 16.9), respectively. Surgical resection was attempted in 2 patients, and pathology showed a complete response (n = 1) and residual 2-mm tumor (n = 1). There were 8 serious adverse events and none related to EUS or EUS-PDT.
EUS-PDT for LAPC appears to be safe and produces measurable imaged-defined tumor necrosis. Phase 2 studies are warranted. (Clinical trial registration number: NCT01770132.)
In this work, we develop models and a fault detection and isolation (FDI) methodology for heating, ventilation and air conditioning (HVAC) systems that utilizes recurrent neural networks (RNN). The ...FDI design does not require the existence of plant fault history, mechanistic models or a set of expert rules to isolate faults. The key is to first use plant data to build predictive models and input/output estimators, and then embed them within FDI filters. A distributed FDI framework is designed consisting of local FDI (LFDI) schemes that communicate with each other for improved FDI. The distributed FDI framework enables diagnosis of multiple faults in different components of the HVAC system when a fault in one of the control components directly affects the other subsystems. The effectiveness of the proposed FDI scheme is shown via simulation examples on a simulation test bed, as well as using real data. The simulations revealed superior performance of the proposed FDI methodology over FDI approaches using subspace based models for both simulation and real data cases.
•Model-free control, staging and sequencing of VRF with multiple outdoor units.•ESC integrated staging and sequencing logic of outdoor-unit compressors and coils.•Stage off least-efficient compressor ...found by extremum seeking under reducing load.•Mode switching of least-efficient outdoor-unit coil found by extremum seeking.•Simulation validation with Modelica model of a VRF with multiple outdoor units.
This paper presents a model-free control and automatic staging strategy for the operation of a variable refrigerant flow system with multiple outdoor units, which maximizes energy efficiency in real time and handles the outdoor-unit operation during load changes. An extremum seeking controller is used to minimize the total power consumption in real time while the thermal load is regulated with inner loop controllers. Minimization of power with extremum seeking control leads naturally to manipulated input behavior that can be utilized to develop control logic for two aspects of multi-outdoor-unit operation in model-free manner: (1) automatically stage off the outdoor unit with least efficient compressor, and (2) automatically switch the operation of outdoor-unit heat exchanger between the evaporating and condensing mode for simultaneous heating and cooling. As the extremum seeking controller can drive the least-efficient compressor to a lower capacity, the outdoor unit with the least efficient compressor can thus be identified and turned off in a model-free manner under a decreasing load. Under simultaneous heating and cooling operation, the fan speed of the least efficient outdoor-unit heat exchanger will be lower than all other outdoor units, which indicates that the heat exchanger can be switched between operation as a condenser and evaporator to achieve thermal balance for higher efficiency. The proposed strategy is evaluated using a Modelica model of a variable-refrigerant-flow system that consists of three outdoor units and 12 indoor units. The effectiveness of the proposed framework is validated with the simulation study.
Background This retrospective cohort study analyzes the potential risks associated with preoperative fine needle aspiration (FNA) biopsy guided by endoscopic ultrasonography (EUS) in patients ...undergoing distal pancreatectomy. Methods Excluding 204 patients with acute or chronic pancreatitis and those with previous pancreatic resections, 230 consecutive patients with primary pancreatic neoplasms underwent elective distal pancreatectomy between 2002 and 2009. The most common indications were adenocarcinoma (28%), intraductal papillary mucinous neoplasm (IPMN; 20%), and endocrine neoplasms (17%). Two-way statistical comparisons were performed between patients who did (EUS+ ) or did not (EUS− ) undergo preoperative EUS-FNA. Results Distal pancreatectomy was performed open in 118 patients (56%) and laparoscopically in 102 patients (44%). No differences were observed in age, sex, American Society of Anesthesiologists class, operative time, or blood loss between the EUS+ ( n = 179) and EUS− ( n = 51) groups. Splenectomy was performed in 162 patients (70%) and was more common in the EUS+ group. With the exception of adenocarcinoma ( n = 57 32% EUS+ vs n = 6 12% EUS− ; P < .01), the final pathologic diagnosis did not differ significantly between the EUS groups. Postoperative complications were more common in the EUS+ patients with cystic neoplasms (43% vs 16% EUS− ; P = .04). EUS-FNA caused pancreatitis in 2 patients preoperatively. No differences in overall or recurrence-free survival were noted between cancer patients in the EUS groups. Patterns of tumor recurrence were not associated with EUS-FNA. Conclusion Preoperative EUS-FNA is not associated with adverse perioperative or long-term outcomes in patients undergoing distal pancreatectomy for solid neoplasms of the pancreas. The potentially detrimental long-term impact of preoperative EUS-FNA in patients with resectable pancreatic adenocarcinoma was not observed, but will require additional study.
In this paper, we apply an extremum-seeking control strategy to a variable refrigerant flow (VRF) system, where the total power consumption is minimized by adjusting the compressor discharge pressure ...setpoint and the outdoor unit fan mass flow rate, incorporating constraints on the zonal temperature setpoint regulation. A simulation study is conducted using a Modelica dynamic simulation model of a VRF system with one outdoor unit and four indoor units. Simulation results validate the effectiveness of the proposed method of power minimization with the constraint of zone-temperature regulation. The ESC strategy incorporates online penalty-weight estimation and loop-gain adaption, which are shown to improve convergence.
Background Although the natural history of intraductal papillary mucinous neoplasm (IPMN) remains unclear, large surgical series have reported malignancy in 40% to 90% of main pancreatic duct ...(MPD)–involved IPMN. Accordingly, the 2012 International Consensus Guidelines recommend surgical resection in patients with suspected MPD involvement. We hypothesized that nonoperative management of select patients with suspected MPD-involved IPMN might be indicated. Study Design From 1992 to 2012, 362 patients underwent surgical resection for pathologically confirmed IPMN at a single academic center. A retrospective review of prospectively collected data was performed. Main pancreatic duct involvement was suspected with an MPD diameter ≥5 mm on preoperative imaging. A multivariate analysis was conducted to assess predictors of malignancy. Results Of 362 patients, 334 had complete data for analysis. Main pancreatic duct involvement was suspected preoperatively in 171 patients. Final pathology revealed 20% high-grade dysplastic and 27% invasive IPMN (47% malignant). Preoperative cytopathology and serum carbohydrate antigen 19-9 independently predicted malignancy (p = 0.003 and p = 0.002, respectively) and invasiveness (p < 0.0001 and p = 0.001, respectively). Patients with both negative preoperative cytopathology and normal serum carbohydrate antigen 19-9 (ie, double negatives) had a lower rate of malignancy and invasiveness (28% and 8% vs 58% and 38%; p < 0.0001). The MPD diameter did not predict malignancy or invasiveness (p = 0.36 and p = 0.46, respectively). Conclusions Patients with suspected MPD-involved IPMN have a highly variable rate of malignancy. Despite recent International Consensus Guidelines recommendations, these data suggest that MPD diameter is not an optimal gauge of malignant risk. Nonoperative management of suspected MPD-involved IPMN in select patients, particularly double negatives, might be indicated. Depending on age and comorbidity, operative risk might outweigh the risk of malignant progression in these patients.
Air handling unit performance assessment rules (APAR) is a fault detection tool that uses a set of expert rules derived from mass and energy balances to detect faults in air handling units (AHUs). ...Control signals are used to determine the mode of operation of the AHU. A subset of the expert rules which correspond to that mode of operation are then evaluated to determine whether a fault exists. APAR is computationally simple enough that it can be embedded in commercial building automation and control systems and relies only upon the sensor data and control signals that are commonly available in these systems. APAR was tested using data sets collected from a “hardware-in-the-loop” emulator and from several field sites. APAR was also embedded in commercial AHU controllers and tested in the emulator.
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