Low Settings Research Articles

Hardware-in-Loop (HIL) Testbed Design of Thermal Power Plant for Threat Modeling and Attack Vector Analysis

Industrial control systems (ICSs) are extensively utilized worldwide to control and regulate various processes in energy utilities. It consists of various field devices, control and monitoring devices and communication devices. This paper focuses on the testing and analysis of various attack vectors that could potentially occur in a hardware-in-loop (HIL) Industrial Control System (ICS) testbed designed for a 500 MW thermal power plant. In this testbed, four typical process scenarios have been identified that can be manipulated through cyber-attacks, leading to severe issues such as plant shutdown or even explosions. The four significant plant scenarios recognized include minimal coal mill levels and increased temperatures in the classifier, heightened primary airflow to the coal mill, the tripping of an ID fan, and adjustment of the Super-heater temperature to its lowest setting. Also, we utilize the STRIDE threat modeling methodology to accurately represents the elements of Cyber-Physical Systems (CPS), their inter-dependencies, and the potential attack entry points and system vulnerabilities.

Not All Flat-Panel C-Arms Are Created Equal: A Comparison of Three Major Manufacturers.

Introduction: Flat-panel detector C-arms (FCs) are reported to reduce radiation exposure and improve image quality compared with conventional image intensifier C-arms (CCs). The purpose of this study was to compare radiation exposure and image quality between three commonly used FCs. Materials and Methods: A cadaver model was placed in the prone position to simulate percutaneous nephrolithotomy. We compared the following three FCs: OEC Elite CFD from GE HealthCare, Zenition 70 from Philips, and Ziehm Vision RFD from Ziehm Imaging. To measure the radiation dose, optically stimulated luminescence dosimeters (OSLDs) were utilized during five 300-second trials, conducted under three settings: automatic exposure control (AEC), AEC with low dose (LD), and LD with the lowest pulse rate (LDLP). Ten blinded urologists evaluated the image quality. Data were statistically analyzed using the analysis of variance (ANOVA) and Tukey's B post hoc tests. Results: In the AEC setting, the Philips C-arm demonstrated lower ventral OSLD exposure (42,446 mrad) compared with both the GE (51,076 mrad) and Ziehm (83,178 mrad; p < 0.001) C-arms. Similarly, in the LD setting, the Philips C-arm resulted in less ventral OSLD exposure (25,926 mrad) than both the Ziehm (30,956 mrad) and GE (38,209 mrad; p < 0.001) C-arms. Meanwhile, in the LDLP setting, the Ziehm C-arm showed less ventral OSLD exposure (4019 mrad) than both the GE (7418 mrad) and Philips (8229 mrad; p < 0.001) C-arms. All three manufacturers received adequate image quality ratings at the AEC and LD settings. However, at LDLP, the Ziehm C-arm received inadequate ratings in 8% of images, whereas both the GE and Philips C-arms received 100% adequate ratings (p = 0.016). Conclusions: Radiation produced by flat-panel C-arms varies dramatically, with the highest exposure (Ziehm) being almost double the lowest (Philips) in AEC. Improved picture quality at the lowest settings may come at the cost of increased radiation dose. Surgeons should carefully select the machine and settings to minimize radiation exposure while still preserving the image quality.

Influence of generator parameters on cutting width during WEDM process

The primary objective of this paper is to rigorously analyse the influence of selected parameters on the cut width in the context of Wire Electric Discharge Machining (WEDM). The parameters under investigation, each varied at different levels, include pulse width, servo reference mean voltage, time interval between two pulses, discharge frequency, and wire feed speed. As the workpiece material, sintered carbide K10 was used. Data for the response variable, cut width, was meticulously collected using two high-precision instruments: the Zoller Genius 3s and the Alicona InfiniteFocusSL. Among the parameters studied, the mean reference voltage emerged as the most influential variable. It holds a commanding lead with a percentage contribution of as much as 82.4 %, making it nearly 15 times more impactful than the second most influential parameter, which is pulse width. At its lowest setting, or first level, the mean reference voltage results in a record low cut width. Conversely, at its highest setting, or third level, it leads to a record high cut width. This comprehensive analysis not only quantifies the relative importance of each parameter but also provides valuable insights into the optimal settings for achieving desired cut widths. The findings have significant implications for improving the efficiency and precision of WEDM processes.

An Adjustable Magnetic Levator Prosthesis for Customizable Eyelid Reanimation in Severe Blepharoptosis II: Randomized Evaluation of Angular Translation.

Examine the effect of force modulation via angular translation of a static magnetic field for customizable treatment of severe blepharoptosis. Prototype adjustable-force magnetic levator prostheses (aMLP) consisted of a spectacle-mounted magnet in rotatable housing and small eyelid-attached magnets embedded in a biocompatible polymer. Interpalpebral fissure (IPF) of 17 participants with severe blepharoptosis was continuously measured for one minute at five spectacle magnet angles, with order randomized and participant and data analyst masked. The hypothesis that angular position affected opening IPF (o-IPF), minimum blink IPF (m-IPF), and comfort ratings (1-10) was tested. The aMLP improved o-IPF from 4.5 mm without the device to 6.2 mm on the lowest force setting (P < 0.001) and 7.1 mm on the highest setting (P < 0.001) and allowed for complete volitional blink regardless of setting (average m-IPF 0.4 mm and no change with aMLP; P = 0.76). Spontaneous blink without the device (2.0 mm) was affected on the highest force setting (m-IPF 3.9 mm; P < 0.001) but only marginally so on the lowest setting (3.0 mm; P = 0.06). Comfort (7.6/10) did not vary with the angle (P > 0.36). Profile analysis found substantial individual responses to angle (P < 0.001), confirming the value of customization. Angular translation provided adjustable force, which had a statistically and clinically meaningful impact on eye opening and the completeness of the spontaneous blink. This quantitative evidence supports continued use of the angular translation mechanism for force adjustment in the customizable magnetic correction of severe blepharoptosis. Evidence for the benefit of customizable magnetic force via angular translation in a larger sample of participants than reported previously.

Cooperative Body Channel Communications for Energy-Efficient Internet of Bodies

The Internet of Bodies (IoB) is a network formed by wearable, implantable, ingestible, and injectable smart devices to collect physiological, behavioral, and structural information from the human body. Thus, the IoB technology can revolutionize the quality of human life by using these context-rich data in myriad smart-health applications. Radio frequency (RF) transceivers have been typically preferred due to their availability and maturity. However, for most RF standards (e.g., Bluetooth low energy), the highly radiative omnidirectional RF propagation (even at the lowest settings) reaches tens of meters of coverage, thereby reducing energy efficiency, causing interference and co-existence issues, and raising privacy and security concerns. On the other hand, body channel communication (BCC) confines low-power and low-frequency (10 kHz–100 MHz) signals to the human body, leading to more secure and efficient communications. Since energy efficiency is one of the critical design parameters of IoB networks, this article focuses on energy-efficient orthogonal body channel access (OBA) and non-OBA (NOBA) schemes with and without cooperation. To this aim, three main BCC topologies are presented: 1) point-to-point channel; 2) medium access channel; and 3) broadcast channel. These topologies are then used as building blocks to create IoB networks relying on OBA and NOBA schemes for downlink (DL) and uplink (UL) traffic. For all schemes and traffic directions, optimal transmit power and phase time allocations are derived in closed-form, which is essential to reduce energy consumption by eliminating computational power. The closed-form expressions are further leveraged to obtain maximum network size as a function of data rate requirement, bandwidth, and hardware parameters.

Portable air cleaners and residential exposure to SARS-CoV-2 aerosols: A real-world study.

Individuals with COVID‐19 who do not require hospitalization are instructed to self‐isolate in their residences. Due to high secondary infection rates in household members, there is a need to understand airborne transmission of SARS‐CoV‐2 within residences. We report the first naturalistic intervention study suggesting a reduction of such transmission risk using portable air cleaners (PACs) with HEPA filters. Seventeen individuals with newly diagnosed COVID‐19 infection completed this single‐blind, crossover, randomized study. Total and size‐fractionated aerosol samples were collected simultaneously in the self‐isolation room with the PAC (primary) and another room (secondary) for two consecutive 24‐h periods, one period with HEPA filtration and the other with the filter removed (sham). Seven out of sixteen (44%) air samples in primary rooms were positive for SARS‐CoV‐2 RNA during the sham period. With the PAC operated at its lowest setting (clean air delivery rate [CADR] = 263 cfm) to minimize noise, positive aerosol samples decreased to four out of sixteen residences (25%; p = 0.229). A slight decrease in positive aerosol samples was also observed in the secondary room. As the world confronts both new variants and limited vaccination rates, our study supports this practical intervention to reduce the presence of viral aerosols in a real‐world setting.

Thermography of cannabis extract vaporization cartridge heating coils in temperature- and voltage-controlled systems during a simulated human puff.

Vaporized cannabis is believed to be safer than smoking, but when heated to excessive temperatures nearing combustion (>900 °C) harmful byproducts may form. While some cannabis extract vaporizers operate well below these high temperatures, heating coil temperatures obtained during actual use are frequently not reported and many operate at high temperatures. We report on two major objectives: 1) development of an infrared thermography method to measure heating coil temperatures in cannabis extract vaporizers during a simulated puff and 2) a comparison of temperature- to voltage- controlled cannabis extract vaporization systems during a puff. Infrared thermography was used to measure heating coil temperatures in one temperature-controlled and two voltage-controlled systems. The cartridges were modified for direct line-of-sight on the heating coils, the wick and coils were saturated with cannabis extract, and fixtures were developed to force two liters per minute air flow past the coils for the full duration of the puff allowed by the device. The voltage-controlled systems produced higher temperatures with greater variability than the temperature-controlled system. At the highest temperature setting (420 °C) the temperature-controlled system reached an average heating coil temperature of 420 ± 9.5 °C whereas the 4.0V setting on the variable voltage system reached an average temperature of 543 ± 95.9 °C and the single voltage (3.2V) system an average of 450 ± 60.8 °C. The average temperature at the lowest setting (270 °C) on the temperature-controlled system was 246 ± 5.1 °C and the variable voltage system (2.4V) was 443 ± 56.1 °C. Voltage alone was a poor indicator of coil temperature and only the temperature-controlled system consistently maintained temperatures less than 400 °C for the full puff duration. These lower temperatures could reduce the likelihood of harmful thermal degradation products and thus may reduce potential health risk to consumers when vaporizing cannabis extracts.

Cold Stress during Flowering Alters Plant Structure, Yield and Seed Quality of Different Soybean Genotypes

The objective of the study was to evaluate the effect of cold stress at flowering stage on plant structure, yield and chemical composition of seeds of 15 soybean cultivars. The study was conducted in 2019–2020, using the complete randomization method, in three replications. Fifteen soybean cultivars belonging to three maturity groups: early (EC), middle-early (MC) and late (LC) cultivars were included. Weekly cold stress (17/13 °C day/night) was applied at plant flowering stage. In the control treatment, plants were kept under natural conditions (24/17 °C day/night). Our research showed that cold stress negatively influenced the elements of plant structure: height, number of nodes, stem dry mass, number and weight of pods, number and weight of seeds per plant, as well as yield of soybean seeds, reducing it on average by 24%, as compared to the control treatment. The highest yield decrease was found in LC cultivars (31.2%), while a smaller and similar one in EC and MC cultivars (by 19.7 and 20.1%, respectively). Significant varietal differences were found for plant biometric traits and seed yield. EC cultivars had the lowest set first pod, as well as the lowest number of nodes, number of pods and seeds, pod and seed weight per plant, and seed yield. MC cultivars had the highest set first pod, and the smallest stem DM and seed yield average by 29.2% higher compared to EC cultivars. LC cultivars had the highest stem DM, number of pods and seeds, and pod and seed weight per plant compared to the other cultivar groups, and yield by 22.8% higher compared to EC cultivars. The experimental factors significantly affected crude protein, crude fat, and crude ash content, while they did not differentiate water-soluble carbohydrate and crude fiber content. Cold stress at the flowering stage caused a significant increase in protein content (by 4.1% on average) and ash content (by 3.8%) and a decrease in fat concentration (by 6.9%) in soybean seeds. Differences in nutrient content among cultivars were a genetic trait not related to cultivar maturity.

The effect of CO2 loading on the properties of normal concrete vs fly ash concrete

Purpose There is an increase in greenhouse gasses and global climate change is frequently reported on. What can be done? Certainly to try and reduce the carbon footprint, which is not a new topic, by encouraging applications and activities for concrete during its lifetime (Portland Cement Association, 2019). This study aims to focus on introducing CO2 to normal and fly ash concrete and thus investigating the effect on the carbon footprint of the samples and the effectiveness of the CO2 introduction methods, namely, carbonated water addition during the mixing process and by means of an infusion pipe directly into the concrete when the samples are casted and have been casted. Design/methodology/approach The feasibility of carbon dioxide storage within concrete is determined by investigating the effects of introduced carbon dioxide into concrete samples and the effectiveness of the concrete at storing carbon dioxide. The concrete was mixed in a 1:3:3 ratio for the OPC or blended 52.5 R cement:sand:stone (22 mm) with a 28 day strength of 50 MPa. Samples were also prepared containing low-grade fly ash cement contents ranging from 15% to 60%. CO2 was introduced to the concrete via carbonated mixing water and an infusion pipe system directly to the hardening concrete cubes. In total, 16 g CO2 bicycle carbon dioxide inflators and valve system were used to infuse the concrete over a period of a week until the canister was emptied with valve release on the lowest setting. A compression test was carried out to determine the strength of the concrete cubes with, and without, the introduction of carbon dioxide. Results were also obtained using a scanning electron microscope (SEM) and energy dispersive x-ray spectrometer (EDS) to determine how the carbon dioxide changed the microscopic composition and chemical composition of the concrete. A microcontroller with carbon dioxide sensors was used to gather carbon dioxide emission data for a period of three months. Findings The compressive strength tests show by introducing carbon dioxide to the concrete, the compressive strength has increased by as much as 13.86% as expected from the literature. Furthermore, by infusing carbon dioxide with the fly ash blended cement, will give a higher strength compared to the control with ordinary portland cement. This correlates to an overall reduction in cost for the structure. The optimal fly ash content for the control with minimal strength degradation is 30%. Where the optimal fly ash content for the concrete with carbon dioxide stored within, is 45%. The SEM analysis showed the concrete with sequestered carbon dioxide has significantly more calcium silicate hydrate (C-S-H) gel formation, thus the strength increase. Furthermore, the carbon dioxide emission test showed the concrete with infused carbon dioxide stores carbon dioxide more efficiently compared to the control sample. With the data showing the infused sample releases 11.19% less carbon dioxide compared to the control sample. However, the carbonated water sample releases 20.9% more carbon dioxide when compared to the control sample. Thus the introduction of carbon dioxide by means of infusion is more effective. Practical implications This is a practical pilot investigation of carbon dioxide introduction via two methods, one being infusion of CO2 into normal concrete and fly ash concrete and two, mixing normal and fly ash concrete with carbonated water. These results show, cheaper cement can be used to achieve equivalent or better strength. This can help in the reduction of the construction industry’s carbon footprint. Originality/value By reducing the construction industry’s carbon footprint with this research results, a saving can not only be made financially in the construction industry, but this will help to preserve our environment for future generations.

Exploring small-scale chemostats to scale up microbial processes: 3-hydroxypropionic acid production in S. cerevisiae

BackgroundThe physiological characterization of microorganisms provides valuable information for bioprocess development. Chemostat cultivations are a powerful tool for this purpose, as they allow defined changes to one single parameter at a time, which is most commonly the growth rate. The subsequent establishment of a steady state then permits constant variables enabling the acquisition of reproducible data sets for comparing microbial performance under different conditions. We performed physiological characterizations of a 3-hydroxypropionic acid (3-HP) producing Saccharomyces cerevisiae strain in a miniaturized and parallelized chemostat cultivation system. The physiological conditions under investigation were various growth rates controlled by different nutrient limitations (C, N, P). Based on the cultivation parameters obtained subsequent fed-batch cultivations were designed.ResultsWe report technical advancements of a small-scale chemostat cultivation system and its applicability for reliable strain screening under different physiological conditions, i.e. varying dilution rates and different substrate limitations (C, N, P). Exploring the performance of an engineered 3-HP producing S. cerevisiae strain under carbon-limiting conditions revealed the highest 3-HP yields per substrate and biomass of 16.6 %C-mol and 0.43 g gCDW−1, respectively, at the lowest set dilution rate of 0.04 h−1. 3-HP production was further optimized by applying N- and P-limiting conditions, which resulted in a further increase in 3-HP yields revealing values of 21.1 %C-mol and 0.50 g gCDW−1 under phosphate-limiting conditions. The corresponding parameters favoring an increased 3-HP production, i.e. dilution rate as well as C- and P-limiting conditions, were transferred from the small-scale chemostat cultivation system to 1-L bench-top fermenters operating in fed-batch conditions, revealing 3-HP yields of 15.9 %C-mol and 0.45 g gCDW−1 under C-limiting, as well as 25.6 %C-mol and 0.50 g gCDW−1 under phosphate-limiting conditions.ConclusionsSmall-scale chemostat cultures are well suited for the physiological characterization of microorganisms, particularly for investigating the effect of changing cultivation parameters on microbial performance. In our study, optimal conditions for 3-HP production comprised (i) a low dilution rate of 0.04 h−1 under carbon-limiting conditions and (ii) the use of phosphate-limiting conditions. Similar 3-HP yields were achieved in chemostat and fed-batch cultures under both C- and P-limiting conditions proving the growth rate as robust parameter for process transfer and thus the small-scale chemostat system as powerful tool for process optimization.

Explant Analysis from a Patient Exhibiting Rapid Acceleration of Parkinson Disease Symptoms and Hypercobaltemia Following Metal-on-Metal Total Hip Arthroplasty: A Case Report.

A 46-year-old man developed rapidly progressing Parkinson disease symptoms after metal-on-metal total hip arthroplasty, worsening to the extent that he underwent implantation of a right subthalamic deep brain stimulator (DBS). A serum cobalt level of 116 μg/L was measured shortly after DBS implantation, and revision arthroplasty was performed using ceramic-on-polyethylene bearings. After revision, the patient's serum cobalt level fell below 1 μg/L, the Parkinson disease symptoms improved, and he reduced the DBS to its lowest setting. Explant analysis showed substantial material loss from the bearing surfaces of one hip. Future studies should evaluate the possible link between Parkinson disease symptoms and prosthesis wear-induced hypercobaltemia.

Use of the Thoracolumbar Facet Transition as a Method of Identifying the T12 Segment

Purpose: Evaluate the reliability of the change from the flat, posterolaterally oriented facets of the thoracic segments to the curved, posteromedially oriented facets of the lumbar spine, the “facet transition”, as a marker for the T12 segment and determine if variations in rib number are associated with lumbosacral transitional segments. Materials and methods: 244 patients underwent whole spine CT examinations and the positions of the thoracolumbar facet transition, type of thoracolumbar facet transition (gradual or abrupt), position of the lowest thoracic ribs, and presence or absence of lumbosacral transitional anatomy were recorded. A Fisher Exact Test was used to determine if there was an association between a variant number of ribs and transitional anatomy at the lumbosacral junction. Results: The thoracolumbar facet transition was located at the eighteenth segment in 50/244 (20%), nineteenth segment in 184/244 (75%), and twentieth segment in 10/244 (4%) of cases. The thoracolumbar facet transition was abrupt in 227/244 (93%). The lowest set of ribs was observed at the nineteenth segment in 225/244 (92%), twentieth segment in 11/244 (5%), and eighteenth segment in 8/244 (3%). The lowest fully-formed intervertebral disc was located between the twenty-third and twenty-fourth segments in 9/244 (4%), twenty-fourth and twenty-fifth segments in 216/244 (88%), and twenty-fifth and twenty-sixth segments in 19/244 (8%). Coexistent lumbosacral transitional anatomy was seen in 5/7 (71%) with eleven, 8/11 (73%) with thirteen, and 24/234 (10%) with twelve ribs. There was an association between variant numbers of ribs and coexistent lumbosacral transitional anatomy (p<0.5). Conclusion: The thoracolumbar facet transition is not a reliable method of identifying the T12 segment. There are no known landmarks that reliably identify the lumbar segments. Accurate numbering of the lumbar spine requires counting caudally from C2.

Anti-Competitive Behaviours and the Remedies Available for Redress

In this chapter, core doctrines of competition law generally applied by national authorities are reviewed. Most competition laws examine anti-competitive behavior in relation to agreements between enterprises, on the one hand, and monopolization or abuse of dominant position, on the other. Anti-competitive activity is further viewed as either ‘horizontal’ or ‘vertical’. Horizontal anti-competitive activity refers to conduct among independent enterprises that are suppliers of competitive (or potentially competitive) goods or services. Vertical anti-competitive activity refers to the supply chain controlled by a producer, beginning with inputs to production, into production, intermediate distribution and, ultimately, the retail sale of goods or services.Some types of agreement between enterprises are so inherently anti-competitive that proof of the existence of the agreement is sufficient to establish a violation. Such agreements are referred to either as per se anti-competitive or hard-core competition law violations. Other types of conduct that may seem anti-competitive on their face may also have a pro-competitive justification, such that competition authorities assess the balance. This balancing is often referred to as assessment under the “rule of reason”. For a competition law violation to be found, the anti-competitive aspect of the arrangement should outweigh potential pro-competitive benefits.Examples of horizontal anti-competitive behavior that are per se illegal in most jurisdictions include price-fixing among competitors, output restraints and allocation of geographic territories. Examples of vertical restraints that are per se illegal in many, but not all, jurisdictions are resale price maintenance (or fixing the minimum price at which retailers may sell) and “exclusive grantback” requirements in patent licenses.There are some significant risks of anti-competitive conduct in pharmaceuticals markets that are fairly widespread and deserve close attention from competition authorities. These include bid manipulation in procurement of health technologies, whereby a group of potential competitors may agree not to submit bids below a set price and to allocate the ‘lowest set price’ bid to a particular firm. Such activity may also involve inappropriate payments to government officials who might otherwise report the anti-competitive practice. Anti-competitive conduct by patent-owning enterprises may include requiring a distributor or retailer of health technologies to purchase a complete line of products as a condition of purchasing a particular product or products (i.e. a tying arrangement). Perhaps the most widely discussed form of anti-competitive conduct involving patent owners involves ‘buying out’ generic challenges to patents that might otherwise result in generic products entering the market at an early date. Such buyouts upset the balance legislators strive to achieve between granting patents and authorizing their challenge to foster competition. Mergers and acquisitions may adversely affect product markets by, for example, allowing combined companies to raise prices for therapies previously in competition with each other.Anti-competitive conduct affects markets for innovation, such as when a patent is illegitimately used to prevent the development of new products not within the scope of the patent, or when patent-owning companies combine to control markets. Mergers and acquisitions can affect markets for innovation by reducing potential RD it may unilaterally dictate terms. One objective surrounding the control of mergers and acquisitions is to prevent an enterprise from combining with others precisely to take a dominant position in the market.This chapter concludes with a discussion of the types of remedies that are available to national authorities and private parties as redress for anti-competitive conduct. It is not uncommon for the government to enter into some form of settlement agreement with an accused enterprise pursuant to which that enterprise agrees to cease its anti-competitive activities and may also make a payment either as damages or as a penalty. Such settlements may be approved and/or supervised by courts.In some jurisdictions, particularly the United States, a good deal of competition enforcement is undertaken by private actors suing for damages. Anti-competitive conduct may also be subject to criminal penalties including substantial fines, and imprisonment for individuals. Specific types of remedies may be used to address anti-competitive conduct that is undertaken to block the introduction of generic products. This may include requiring pharmaceutical patent owners to compensate public procurement authorities, generic producers and others for damages occasioned by the unwarranted invocation of patents. Strong consideration should be given to prohibiting patent owners from “buying out” generic producers’ challenges to patent validity or assertions of non-infringement. Other types of specific remedies may be considered.

Laser Beam Filtration for High Spatial Resolution MALDI Imaging Mass Spectrometry

We describe an easy and inexpensive way to provide a highly defined Gaussian shaped laser spot on target of 5μm diameter for imaging mass spectrometry using a commercial MALDI TOF instrument that is designed to produce a 20μm diameter laser beam on target at its lowest setting. A 25μm pinhole filter on a swivel arm was installed in the laser beam optics outside the vacuum ion source chamber so it is easily flipped into or out of the beam as desired by the operator. The resulting ion images at 5μm spatial resolution are sharp since the satellite secondary laser beam maxima have been removed by the filter. Ion images are shown to demonstrate the performance and are compared with the method of oversampling to achieve higher spatial resolution when only a larger laser beam spot on target is available.

048 RADIATION EXPOSURE REDUCTION DURING TRANSCATHETER AORTIC VALVE IMPLANTATION (TAVI) PROCEDURES

Introduction Trans-catheter aortic valve replacement (TAVR) is a new treatment for symptomatic aortic stenosis in patients who are considered high risk or inoperable for conventional surgical aortic valve replacement. The radiation dose from this procedure has not been extensively investigated. The methods to keep these doses as low as possible should be actively investigated for the safety of both the patient and the medical team involved. Aims In this single centre analysis, we established our radiation dose and determined whether lower fluoroscopy and cine imaging settings would reduce patient and operator doses while maintaining an acceptable image quality. Methods Data on radiation exposure was collected for consecutive patients undergoing TAVI. Using a single plane C-arm, the settings were changed from coronary to electrophysiology (EP), this resulted in a reduction for fluoroscopy, from 15 pulse-progressive fluoroscopy (ppf) to 3.75–7.5 ppf and for cine acquisition, from 15 frames per second (fps) to 3.75–7.5 fps for access site management. We compared the radiation doses in this lower settings (LS) group with the standard settings (SS) group. Results Data for 68 consecutive patients was collected over a period of 11 months from the Royal Victoria Hospital, Belfast. The median dose area product using the standard setting was 10 210 cGy cm 2 as compared to 6928 cGy cm 2 for the lower setting group was statistically significant (p value 0.006). The screening time, procedure time and contrast volume in the two groups were not statistically different. There were no procedural deaths or radiation burns in either group at 30 days follow-up. Conclusions This study demonstrates that it is possible to reduce radiation dose by approximately 32% by adhering to radiation safety protocols, employing protective measures and lowering cine-fluoroscopy imaging settings, while preserving acceptable image quality.

Consequence of Use of Lower Dose Flat Plate Fluoroscopy in Pediatric Patients Undergoing Ablation for Supraventricular Tachycardia

Traditional imaging for ablation of supraventricular tachycardia has been fluoroscopy, although 3-dimensional electroanatomic mapping (3D) has been demonstrated to reduce radiation exposure. This study compares a technique for the reduction of radiation, low-dose fluoroscopy (LD), with standard-dose fluoroscopy (SD) and 3D with SD (3D-SD). This was a single institutional retrospective cohort study. All patients undergoing initial ablation for atrioventricular reentrant tachycardia (AVRT) or atrioventricular nodal reentrant tachycardia (AVNRT) from 2009 to 2012 were reviewed and divided into 3 groups: (1) SD, (2) 3D (CARTO or NavX) with SD, or (3) LD. LD uses the same equipment as SD but includes customized changes to the manufacturer's lowest settings by decreasing the requested dose to the detector. Primary outcomes were fluoroscopy time and dose area product exposure. One hundred eighty-one patients were included. The median age was 15.0 years (3.3-20.8); 59% had AVRT, 35% had AVNRT, and 6% had both AVRT and AVNRT. LD decreased the dose area product (DAP) compared with SD (637.0 vs 960.1 cGy*cm², p = 0.01) with no difference in fluoroscopy time. 3D-SD decreased fluoroscopy time compared with SD (9.9 vs 18.3 minutes, p <0.001) with DAP of 570.1.0 versus 960.1 cGy*cm² (p = 0.16). LD and 3D-SD had comparable DAP (637.0 vs 570.1 cGy*cm², p = 0.67), even though LD had significantly longer fluoroscopy time (19.9 vs 9.9 minutes, p <0.001). In conclusion, LD during catheter ablation of AVRT and AVNRT significantly reduced the DAP compared with SD and had similar radiation exposure compared with 3D with SD.

Mechanical ventilation of six dogs anaesthetised with isoflurane or sevoflurane delivered by a Komesaroff anaesthetic machine

After intravenous induction, six beagles were connected to a Komesaroff machine provided with a single in-circuit vaporiser and ventilated mechanically at either nine or 14 breaths/minute while anaesthetised with either...

In-Vehicle Exposures to Particulate Matter and Black Carbon

In-vehicle exposures to particulate matter (PM) and black carbon (BC) can be a significant part of personal total exposure. The purpose of this study was to identify determinants of the in-vehicle pollutant level. This study measured in-vehicle exposure to PM number concentrations using an aerosol spectrometer and BC concentration by an aethalometer. The measurement was repeated 3 times a day for 13 consecutive days in May 2007 while a vehicle was driven on a 1-hr predetermined route in Lexington, KY. The vehicle’s windows were closed, its fan was operated at the lowest setting, and air conditioning and heating were off. The average speed of all runs was 37 ± 5.8 km/hr. Arithmetic mean PM1 (particle sizes ±1 μm in aerodynamic diameter) number and BC concentrations were 286 #/cm3 (morning, 302 #/cm3; afternoon, 270 #/cm3; evening, 287 #/cm3) and 1.9 μg/m3 (morning, 2.5 μg/m3; afternoon, 1.6 μg/m3; evening, 1.5 μg/m3), respectively. Average PM and BC concentrations increased during weekdays and decreased during weekends, and PM1 number and BC concentrations were highest in the morning. Particle size distribution for PM1 did not differ with time of day, but the concentration of PM1-10 (particle sizes between 1 and 10 μm in aerodynamic diameter) was higher in the evening and lower in the morning. Peak PM1 number concentrations were observed when the test vehicle approached busy crossroads. In-vehicle PM and BC concentrations were associated with time of the day and location, whereas the in-vehicle 1-hr PM number concentrations were closely associated with distant ambient PM2.5 (particle sizes ±2.5 μm in aerodynamic diameter) concentrations measured at a stationary monitoring site. The findings suggested that in-vehicle exposure is associated with surrounding traffic.

Mechanical ventilation of six dogs anaesthetised with isoflurane or sevoflurane delivered by a Komesaroff anaesthetic machine

After intravenous induction, six beagles were connected to a Komesaroff machine provided with a single in-circuit vaporiser and ventilated mechanically at either nine or 14 breaths/minute while anaesthetised with either...

Evaluation of the effect of machine settings on quantitative three‐dimensional power Doppler angiography: an in‐vitro flow phantom experiment

Three-dimensional (3D) ultrasound is being used increasingly to acquire and subsequently quantify power Doppler data within the clinical setting. One proprietary software package calculates three 3D vascular indices: the vascularization index (VI), the flow index (FI), and the vascularization flow index (VFI). Our aim was to evaluate how different settings affect the Doppler signal in terms of its quantification by these three indices within a 3D dataset. A computer-driven 'flow phantom' was used to continuously pump a nylon particle-based blood mimic (Orgasol(trade mark)) around a closed system through a C-flex(trade mark) tube embedded in an agar-based tissue mimic. The test tanks were insonated with a modified 3D transvaginal 4-8-MHz ultrasound transducer (V530D) and power Doppler data were acquired over a series of different settings. Each experiment involved the manipulation of just one Doppler setting in order to study it in isolation. As expected, all of the power Doppler settings, when altered, were found to effect significant changes (P < 0.05) in the VI, FI and VFI. The gain and signal power had the greatest effect, producing no Doppler signals at the lowest settings and the highest recordable indices at the maximum settings. The pulse repetition frequency (PRF) was the next most influential setting but a Doppler signal was seen and measurable at all of the different settings. The other Doppler settings had a much less profound effect on the vascular indices, with subtle but significantly different measures across the full range of settings. The speed of data acquisition was also found to affect the vascular indices, all of which were reduced when the fast mode was used although the only significant effect was on the VFI. The VI, FI and VFI are all affected significantly by variations in power Doppler settings and by the speed of acquisition. The gain and signal power have the greatest effect on the power Doppler signal, followed closely by the PRF. The other settings and speed of acquisition also influence the signal, but to a much lesser degree. It is essential to maintain Doppler settings if any meaningful comparisons are to be made within and between subjects.