Design and Characterization of CMOS/SOI Image Sensors

The design, operation, and characterization of CMOS imagers implemented using: 1) regular CMOS wafers with a 0.5-mum CMOS analog process; 2) regular CMOS wafers with a 0.35-mum CMOS analog process; and 3) silicon-on-insulator (SOI) wafers in conjunction with a 0.35-mum CMOS analog process, are discussed in this paper. The performances of the studied imagers are compared in terms of quantum efficiency, dark current, and optical bandwidth. It is found that there is strong dependence of quantum efficiency of the photodiodes on the architecture of the image sensor. The results of this paper are useful for designing and modeling CMOS/SOI image sensor

Study of CMOS-SOI Integrated Temperature Sensing Circuits for On-Chip Temperature Monitoring

This paper investigates the concepts, performance and limitations of temperature sensing circuits realized in complementary metal-oxide-semiconductor (CMOS) silicon on insulator (SOI) technology. It is shown that the MOSFET threshold voltage (Vt) can be used to accurately measure the chip local temperature by using a Vt extractor circuit. Furthermore, the circuit’s performance is compared to standard circuits used to generate an accurate output current or voltage proportional to the absolute temperature, i.e., proportional-to-absolute temperature (PTAT), in terms of linearity, sensitivity, power consumption, speed, accuracy and calibration needs. It is shown that the Vt extractor circuit is a better solution to determine the temperature of low power, analog and mixed-signal designs due to its accuracy, low power consumption and no need for calibration. The circuit has been designed using 1 µm partially depleted (PD) CMOS-SOI technology, and demonstrates a measurement inaccuracy of ±1.5 K across 300 K–500 K temperature range while consuming only 30 µW during operation

Novel Miniature and Selective Combustion-Type CMOS Gas Sensor for Gas-Mixture Analysis—Part 1: Emphasis on Chemical Aspects

There is an ongoing effort to fabricate miniature, low cost, sensitive, and selective gas sensors for domestic and industrial uses. This paper presents a miniature combustion-type gas sensor (GMOS) based on a thermal sensor, where a micromachined CMOS–SOI transistor integrated with a catalytic reaction plate acts as a sensing element. This study emphasizes GMOS performance modeling, technological aspects, and sensing-selectivity issues. Two deposition techniques of a Pt catalytic layer suitable for wafer-level processing were compared, magnetron sputtering and nanoparticle inkjet printing. Both techniques have been useful for the fabrication of GMOS sensor, with good sensitivity to ethanol and acetone in the air. However, a printed Pt nanoparticle catalyst provides almost twice as much sensitivity as compared to that of the sputtered catalyst. Moreover, sensing selectivity in the ethanol/acetone gas mixture was demonstrated for the GMOS with a Pt nanoparticle catalyst. These advantages of GMOS allow for the fabrication of a low-cost gas sensor that requires a low power, and make it a promising technology for future smartphones, wearables, and Internet of Things (IoT) applications

Is perioperative COVID-19 really associated with worse surgical outcomes? A nationwide COVIDSurg propensity-matched analysis

BACKGROUND: Patients undergoing surgery with perioperative COVID-19 are suggested to have worse outcomes, but whether this is COVID-related or due to selection bias remains unclear. We aimed to compare the postoperative outcomes of patients with and without perioperative COVID-19. METHODS: Patients with perioperative COVID-19 diagnosed within 7 days before or 30 days after surgery between February and July 2020 from 68 US hospitals in COVIDSurg, an international multicenter database, were 1:1 propensity score matched to patients without COVID-19 undergoing similar procedures in the 2012 American College of Surgeons National Surgical Quality Improvement Program database. The matching criteria included demographics (e.g., age, sex), comorbidities (e.g., diabetes, chronic obstructive pulmonary disease, chronic kidney disease), and operation characteristics (e.g., type, urgency, complexity). The primary outcome was 30-day hospital mortality. Secondary outcomes included hospital length of stay and 13 postoperative complications (e.g., pneumonia, renal failure, surgical site infection). RESULTS: A total of 97,936 patients were included, 1,054 with and 96,882 without COVID-19. Prematching, COVID-19 patients more often underwent emergency surgery (76.1% vs. 10.3%, p < 0.001). A total of 843 COVID-19 and 843 non-COVID-19 patients were successfully matched based on demographics, comorbidities, and operative characteristics. Postmatching, COVID-19 patients had a higher mortality (12.0% vs. 8.1%, p = 0.007), longer length of stay (6 [2-15] vs. 5 [1-12] days), and higher rates of acute renal failure (19.3% vs. 3.0%, p < 0.001), sepsis (13.5% vs. 9.0%, p = 0.003), and septic shock (11.8% vs. 6.0%, p < 0.001). They also had higher rates of thromboembolic complications such as deep vein thrombosis (4.4% vs. 1.5%, p < 0.001) and pulmonary embolism (2.5% vs. 0.4%, p < 0.001) but lower rates of bleeding (11.6% vs. 26.1%, p < 0.001). CONCLUSION: Patients undergoing surgery with perioperative COVID-19 have higher rates of 30-day mortality and postoperative complications, especially thromboembolic, compared with similar patients without COVID-19 undergoing similar surgeries. Such information is crucial for the complex surgical decision making and counseling of these patients. (J Trauma Acute Care Surg. 2023;94: 513-524. Copyright (C) 2023 American Association for the Surgery of Trauma.)LEVEL OF EVIDENCE: Prognostic and Epidemiologic; Level IV

Outcomes and Their State-level Variation in Patients Undergoing Surgery With Perioperative SARS-CoV-2 Infection in the USA. A Prospective Multicenter Study

Objective: To report the 30-day outcomes of patients with perioperative SARS-CoV-2 infection undergoing surgery in the USA. Background: Uncertainty regarding the postoperative risks of patients with SARS-CoV-2 exists. Methods: As part of the COVIDSurg multicenter study, all patients aged ≥17 years undergoing surgery between January 1 and June 30, 2020 with perioperative SARS-CoV-2 infection in 70 hospitals across 27 states were included. The primary outcomes were 30-day mortality and pulmonary complications. Multivariable analyses (adjusting for demographics, comorbidities, and procedure characteristics) were performed to identify predictors of mortality. Results: A total of 1581 patients were included; more than half of them were males (n = 822, 52.0%) and older than 50 years (n = 835, 52.8%). Most procedures (n = 1261, 79.8%) were emergent, and laparotomies (n = 538, 34.1%). The mortality and pulmonary complication rates were 11.0 and 39.5%, respectively. Independent predictors of mortality included age ≥70 years (odds ratio 2.46, 95% confidence interval [1.65-3.69]), male sex (2.26 [1.53-3.35]), ASA grades 3-5 (3.08 [1.60-5.95]), emergent surgery (2.44 [1.31-4.54]), malignancy (2.97 [1.58-5.57]), respiratory comorbidities (2.08 [1.30-3.32]), and higher Revised Cardiac Risk Index (1.20 [1.02-1.41]). While statewide elective cancelation orders were not associated with a lower mortality, a sub-analysis showed it to be associated with lower mortality in those who underwent elective surgery (0.14 [0.03-0.61]). Conclusions: Patients with perioperative SARS-CoV-2 infection have a significantly high risk for postoperative complications, especially elderly males. Postponing elective surgery and adopting non-operative management, when reasonable, should be considered in the USA during the pandemic peaks