CT Angiography in The Detection of Carotid Body Enlargement in Patients with Hypertension and Heart Failure

Introduction: The carotid body (CB) has previously been found to be enlarged and hyperactive in various disease states such as heart failure (HF), hypertension (HTN), and respiratory disease. Evaluation of CB size in these disease states using imaging has not been performed. The purpose of this case–control study was to compare CB sizes in patients with HF and HTN with those of controls using CT angiography. Methods: A retrospective review was performed on 323 consecutive patients who had neck computed tomography angiography (CTA) exams in 2011. Following extensive review, 17 HF and HTN patients and 14 controls were identified. Two radiologists blinded to the patient disease status made consensus bilateral carotid body (CB) measurements on the CTA exams using a previously described standardized protocol. CB axial cross-sectional areas were compared between HF and HTN cases and controls using a paired t test. Results: The right CB demonstrated a mean cross-sectional area of 2.79 mm2 in HF and HTN patients vs. 1.40 mm2 in controls (p = 0.02). The left CB demonstrated a mean cross-sectional area of 3.13 mm2 in HF and HTN patients vs. 1.53 mm in controls (p = 0.03). Conclusion: Our results provide imaging evidence that the carotid bodies are enlarged in patients with HF and HTN. Our case–control series suggests that this enlargement can be detected on neck CTA

Corona plasma for tar removal

XII+137hlm.;24c

Pulsed corona generation using a high-power semiconductor diode switch

High-power semiconductor opening switches are the most critical components in nanosecond pulsed power systems with inductive energy storage. For industrial applications, such as pulsed corona processing, a long lifetime, high repetition rate, high efficiency and high reliability are required. At the Ioffe Institute, an unconventional switching mechanism has been found, based on the very fast recovery process in a silicon p/sup +/p'nn/sup +/ diode. This paper describes the application of such a 'drift-step recovery diode' for high-power pulsed corona plasma generation. The principle of the diode-based nanosecond pulse generator is discussed in detail. The generator is coupled to a wire-plate corona reactor via a transmission-line-transformer, which has the following advantages: (i) increase of the output voltage, (ii) impedance transformation to improve the matching with the reactor, (iii) protection of the switch against reflections and mismatches, (iv) limitation of the switch current during short-circuit or breakdowns, and (v) easy coupling with a DC-bias voltage. The developed circuit has been tested at both a matched resistive load and a wire-plate pulsed corona reactor. Various ways to improve the matching with the reactor have been evaluated. We found that superposition of the pulse on a DC-bias voltage gives the best result. For example: without DC-bias, more than 50% of the energy-per-pulse reflects back to the source. However, the reflected energy could be reduced to <15% when using a DC-bias voltage of 25 kV

A triggered spark-gap switch for high-repetition rate high-voltage pulse generation

A triggered spark-gap switch together with a LCR trigger circuit has been developed in order to produce high levels of pulsed corona plasma at high-repetition rate and with a long lifetime. The spark-gap switch is flushed in air with a gas flow rate of up to 100 m3/h. Experiments are carried out up to 10 kW average output power, 12 J/pulse, and 900 pps (pulses per second)

Pulsed corona generation using a diode-based pulsed power generator

Pulsed plasma techniques serve a wide range of unconventional processes, such as gas and water processing, hydrogen production, and nanotechnology. Extending research on promising applications, such as pulsed corona processing, depends to a great extent on the availability of reliable, efficient and repetitive high-voltage pulsed power technology. Heavy-duty opening switches are the most critical components in high-voltage pulsed power systems with inductive energy storage. At the Ioffe Institute, an unconventional switching mechanism has been found, based on the fast recovery process in a diode. This article discusses the application of such a drift-step-recovery-diode for pulsed corona plasma generation. The principle of the diode-based nanosecond high-voltage generator will be discussed. The generator will be coupled to a corona reactor via a transmission-line transformer. The advantages of this concept, such as easy voltage transformation, load matching, switch protection and easy coupling with a dc bias voltage, will be discussed. The developed circuit is tested at both a resistive load and various corona reactors. Methods to optimize the energy transfer to a corona reactor have been evaluated. The impedance matching between the pulse generator and corona reactor can be significantly improved by using a dc bias voltage. At good matching, the corona energy increases and less energy reflects back to the generator. Matching can also be slightly improved by increasing the temperature in the corona reactor. More effective is to reduce the reactor pressure

Chemical processes in tar removal from biomass derived fuel gas by pulsed corona discharges

Cleaning or conditioning of fuel gas from biomass gasification is perhaps one of the main obstacles for utilization of biomass as a source of power generation. Various methods exist, but, so far, none of them have been reported to be reliable for long-term operation. In our present research, we try to couple our advancements in pulsed power technology for industrial applications to the application mentioned. Here we focus on the chemical processes that occur during pulsed corona fuel gas cleaning. Experimental results at 200°C show that the main process for tar (heavy aromatic hydrocarbons) removal is mainly via oxidation

High-Temperature Pulsed Corona Processing of Fuel Gas obtained from Biomass Gasification

no abstract

CT Angiography in The Detection of Carotid Body Enlargement in Patients with Hypertension and Heart Failure

Introduction: The carotid body (CB) has previously been found to be enlarged and hyperactive in various disease states such as heart failure (HF), hypertension (HTN), and respiratory disease. Evaluation of CB size in these disease states using imaging has not been performed. The purpose of this case–control study was to compare CB sizes in patients with HF and HTN with those of controls using CT angiography. Methods: A retrospective review was performed on 323 consecutive patients who had neck computed tomography angiography (CTA) exams in 2011. Following extensive review, 17 HF and HTN patients and 14 controls were identified. Two radiologists blinded to the patient disease status made consensus bilateral carotid body (CB) measurements on the CTA exams using a previously described standardized protocol. CB axial cross-sectional areas were compared between HF and HTN cases and controls using a paired t test. Results: The right CB demonstrated a mean cross-sectional area of 2.79 mm2 in HF and HTN patients vs. 1.40 mm2 in controls (p = 0.02). The left CB demonstrated a mean cross-sectional area of 3.13 mm2 in HF and HTN patients vs. 1.53 mm in controls (p = 0.03). Conclusion: Our results provide imaging evidence that the carotid bodies are enlarged in patients with HF and HTN. Our case–control series suggests that this enlargement can be detected on neck CTA