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Introduction Whether ACE inhibitors (ACEi) or angiotensin II receptor blocker (ARB) therapy should be continued, initiated or ceased in patients with COVID-19 is uncertain. Given the widespread use of ACEi/ARBs worldwide, guidance on the use of these drugs is urgently needed. This prospective meta-analysis aims to pool data from randomised controlled trials (RCTs) to assess the safety and efficacy of ACEi/ARB therapy in adults infected with SARS-CoV-2. Methods and analysis RCTs will be eligible if they compare patients with COVID-19 randomised to ACEi/ARB continuation or commencement versuss no ACEi/ARB therapy; study duration ≥14 days; recruitment completed between March 2020 and May 2021. The primary outcome will be all-cause mortality at ≤30 days. Secondary outcomes will include mechanical ventilation, admission to intensive care or cardiovascular events at short-term follow-up (≤30 days) and all-cause mortality at longer-term follow-up (>1 month). Prespecified subgroup analyses will assess the effect of sex; age; comorbidities; smoking status; ethnicity; country of origin on all-cause mortality. A search of ClinicalTrials.gov has been performed, which will be followed by a formal search of trial registers, preprint servers, MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials to identify RCTs that meet inclusion criteria. To date, a search of ClinicalTrials.gov identified 21 potentially eligible trials for this meta-analysis. We will request trial investigators/sponsors to contribute standardised grouped tabular outcome data. Ethics and dissemination Ethics approval and informed consent will be the responsibility of the individual RCTs. Dissemination of results will occur by peer-reviewed publication. The results of our analysis can inform public health policy and clinical decision making regarding ACEi/ARB use in patients with COVID-19 on a global scale. © The Author(s), 2021.

US Environmental Protection Agency (EPA) based its benzene carcinogenicity assessment on the Pliofilm cohort. We evaluated associations between benzene exposure and acute nonlymphocytic leukemia (ANLL) and acute myelocytic leukemia (AML) risks using this cohort's updated exposure estimates and mortality data.We calculated standardized mortality ratios (SMRs) for ANLL/AML using lifetable analyses, with various exposure quantile categories and lag times.Workers in the highest exposure categories had significantly elevated risks of ANLL and AML; no leukemia cases occurred in lower exposure categories. Exposure within 10 years of cancer onset appears most relevant for leukemia induction.Our results confirmed the association between high-level benzene exposures and leukemia risks, and provided further evidence of a threshold effect and relevant exposure window. Our findings call for an updated risk assessment for benzene carcinogenicity using updated exposure estimates and mortality data.

A parallel two-stage acquisition technique is described for direct sequence spread spectrum (DS/SS) range finding applications. The technique offers hardware complexity that scales better with code length than matched filter correlators while providing better performance than sequential detection using comparable hardware.

This paper describes a study of single-phase-series-parallel versus polyphase calibration of electricity meters. Historically there has been some debate regarding the field performance of electromechanical electricity meters that have been calibrated using the series-parallel technique which is common in North America and other areas. A methodology was carefully established that would allow several meter testing laboratories to be verified and traceable to each other. Meters were tested and the data is presented along with data analysis and conclusions.

Position-sensitive detectors (PSD) provide four current outputs that are proportional to the two-dimensional center of mass of a light spot impinging on the face of the detector. This characteristic permits the PSD to be used for sensing the position of a light source. The application motivating the work reported here involved the tracking of a light source located on a surface with approximate dimensions 122 cm wide by 91 cm high located approximately 2 m from the detector. The diameter of the light source was a few millimeters. The work described here demonstrates the feasibility of using a PSD to track the position of a light source with accuracy better than 1 mm from this distance.

Papauer somniferum cell suspension cultures carried out in shake flasks were elicited with chitin under batch and nutrient feeding conditions to increase sanguinarine production. Batch cultures yielded maximum production of 270 mg l −1 upon elicitation during exponential growth phase at extracellular phosphate depletion. The addition of concentrated medium solutions prior to elicitation of stationary phase cultures allowed a modest increase in production to 350 mg l −1 . Further optimization of the nutrient solution yielded production of 575 mg l −1 . Examination of the composition of this nutrient solution showed an absolute requirement of elicited cultures for the presence of carbohydrates, phosphate and sulfate during fedbatch additions for maximum sanguinarine production.

Various Papaver somniferum cell lines species were generated and examined for sanguinarine production either by elicitation with chitin or endogenous production. Initial elicitation experiments gave variable results, with sanguinarine yields and concentrations of up to 4.5% of the biomass dry weight and 202 mg l −1 , respectively, much higher than endogenous levels of production (~ 1 % or ~ 90 mg l −1 ). A closer examination of the growth and major nutrient (carbohydrates, phosphate, nitrate and ammonia) uptake patterns of these cultures revealed interesting insights into this process. Extracellular phosphate concentration near depletion (~ 0.1 mM) was found to be a reliable marker for elicitation and production. Elicited cultures showed an absolute requirement for extracellular carbohydrates and ammonia during the production phase for both survival and maximum production. Highest sanguinarine levels obtained were yield of 5.0%, concentration of 385 mg l −1 , and productivities of 82 and 26 mg l −1 d −1 for the production phase and whole culture duration, respectively.

This paper documents the material presented at the IEEE 1994 Summer Power Meeting Panel on the application of reliability in least cost power system planning, sponsored by the Application of Probability Methods (APM) Subcommittee of the Power System Engineering Committee of IEEE. The paper contains short notes by five panelists, representing five electric utilities in North America, on the application of reliability and value of service analysis in power system planning.

We investigate the crumpling transition for a dynamically triangulated random surface embedded in two dimensions. We find a second order transition for an “edge” discretization of the extrinsic curvature and a third order transition for an alternative “area” discretization, which is identical to surfaces embedded in three and higher dimensions. The results for the edge extrinsic curvature are at variance with those of Kogut and Renken who found a first order transition for a fixed triangulation.

Theoretical relationships are developed to relate the characteristics of a controller transfer function to the stiffness and damping properties of an active magnetic bearing for machine rotors. Both proportional and derivative feedback are shown to be necessary for closed-loop system stability, and, for the ideal case, bearing stiffness and damping properties are shown to be simple linear functions of the proportional and derivative feedback gain constants, respectively. The flexibility of a digitally controlled magnetic bearing is demonstrated by the implementation of algorithms which include second-derivative and integral feedback. Second-derivative feedback is shown to be effective at extending the usable bandwidth of the digital controller, and integral feedback rejects rotor position error in the presence of static loads. The relationship between controller sampling rate and bearing performance is investigated, and it is shown that increased sampling rate and increased amounts of second-derivative feedback have similar effects on the bearing properties. >

Proton therapy is a precise forms of radiation therapy that makes use of high energy proton compared to the conventional, more commonly used and less precise x-ray and electron beams. On the other hand, to fully exploit the proton therapy advantages, very accurate quality controls of the treatments are required. These are mainly related to the dose calculations and treatment planning. Actually dose calculations are routinely performed on the basis of X-ray computed tomography while a big improvement could be obtained with the direct use of protons as the imaging system. In this work we report the results of Monte Carlo simulations for the study of an imaging system based on the use of high energy protons: the proton computed tomography (pCT). The main limitation of the pCT and the current adopted technical solutions, based on the use of the most likely path (MLP) approximation are illustrated. Simulation results are compared with experimental data obtained with a first prototype of pCT system tested with 200 MeV proton beams available at the Loma Linda University Medical Center (LLUMC) (CA).

Publisher Summary This chapter describes several methods for estimating soil hydraulic properties from easily available data, including soil texture and bulk density. The scaling method is introduced to improve the regression models to predict water contents at specific matric potentials using soil texture. The Gregson–Hector–McGovan's (GHM) One-Parameter Model is also introduced to parameterize soil-water-release curves using only one parameter. The method is based on a log linear relationship between water content and matric potential where the slopes and intercepts of the relationships are linearly related. The parameters for this linear relationship are shown to be consistent for a wide range of soils so that a single slope and intercept can be used to generate any moisture-release curve, given a matching water content–matric potential pair. The estimations of water contents could be improved if the slope and intercept values are aggregated by soil texture groupings. A simple equation to predict saturated hydraulic conductivity from soil porosity near saturation can give good results over a wide range of soils. This relationship is improved by including the pore-size distribution parameter from the Brooks–Corey equation. The chapter presents the application of the GHM model to estimate unsaturated hydraulic conductivity.

In train and transit applications, the occurrence of a single hazard (fault) may be quite catastrophic resulting in significant societal costs, ranging from loss of life to major asset damages. The axiomatic safety-critical assessment process (ASCAP) has been demonstrated as a competent method for assessing the risk associated with train and transit systems. ASCAP concurrently simulates the movement of n-trains within a given system from the perspective of the individual trains. During simulation, each train interacts with a series of appliances that are located along the track, within the trains and at a central office. Within ASCAP, each appliance is represented by a probabilistic multistate model, whose state selection is decided using a Monte Carlo process. In lieu of exercising this multistate model for a given appliance, the ASCAP methodology supports the inclusion of actual appliances within the simulation platform. Hence, an appliance can be fault tested in a simulation environment that emulates the actual operational environment to which it will be exposed. The ASCAP software can interface with a given appliance through an input/output (I/O) node contained within its executing platform. This node provides the ASCAP software with the capability of communicating with an external device, such as a track or an onboard appliance. When a train intersects with a particular appliance, the actual appliance can be queried by the ASCAP simulator to ascertain its status. This state information can then be used by ASCAP in lieu of its multi-state model representation of the appliance. This simulation process provides a mechanism to determine the appliance's ability to perform its intended safety-critical function in the presence of hardware/software design faults within its intended operational environment. By being able to quantify these effects prior to deploying a new appliance, credible and convincing evidences can be prepared the to ensure that overall system safety will not be adversely impacted.

The basic question addressed was whether the greater hardware utilization offered by reconfigurable functional units could compensate for a reduction in clock rate. That is, would the average number of clock cycles per instruction improve sufficiently to compensate for a slower clock rate to yield a net improvement in performance? The architecture limited the number of execution units because of constraints external to the execution units. An example of such a constraint would be limited efficient access to a common register file. Under these constraints, inefficient matching of program needs with hardware capabilities limits performance because of hardware idle cycles. The work found very limited conditions that can yield performance improvement using reconfigurable pipelines when compared with static pipelines. Greater promise was found with instruction set enhancements made possible by the reconfigurable pipelines.

The authors discuss methodologies and tools that allow a system to be analyzed using Petri nets or queuing models. Models at this level contain tokens rather than values, and the function of blocks remains undefined. Such analysis is performed early in the design process to evaluate overall system performance. Different methodologies and tools are available to allow design analysis and verification at interpreted levels through hardware design language (HDL) descriptions. Tokens are replaced with specific values for the representation of signals. The methodology presented allows the designer to create uninterpreted models in an environment already capable of interpreted modeling, the VHSIC hardware description language (VHDL). Uninterpreted modeling in an HDL is the first step in the creation of a continuous single-path design environment. >

The design and implementation of an object-oriented topologically partitioned parallel automatic test pattern generation (ATPG) system, ES-TPS, on a multiple-instruction multiple-data (MIMD) distributed-memory multiprocessor are described. The ATPG system is based upon the D-algorithm and performs test generation on a circuit which has been topologically partitioned across several processors. Fault partitioning and algorithmic parallelizations are included in the system to attempt to achieve speedup. >

Ultrathin (0.0025 in.) Si solar cells were selected for use on the Satellite Business System (SBS) 1A solar array to achieve minimum solar array weight and maximum end-of-life solar array power. The design of the ultrathin cell was predicted to produce an improved resistance to radiation degradation and superior current collection efficiency, thus increasing the power per unit area at end of life compared to conventional-thickness silicon solar cells. The ultrathin solar cells were qualified for flight and characterized prior to fabrication of the SBS-1A array. Performance predictions in the mission environment were based on these characteristics and on the measured photovoltaic output of the flight solar cells. The predicted solar array performance has been validated to date within 2% by in-flight test data. >

The conversational constraints of text-to-speech synthesis systems are considered by permitting the human user to control the motions of stimulated articulators in a synthesized vocal track. The positions of these stimulated articulators are used to derive parameters to control a formant synthesizer. It is anticipated that use of this type of speech prosthesis will be more difficult to learn than the use of conventional communication aids, but the flexibility of this approach will be much greater. The difficulty in this approach arises because the complexity of the human interface must be limited while sufficient information must be obtained to permit synthesis of speech sounds at conversational rates. A prototype has been constructed, and experimentation and further development are discussed. >

Long-acting somatostatin analogs have recently become supplemental drugs in the treatment of neurofibroma because of their marked tumor growth inhibitory effect. Somatostatin is currently under extended evaluation in other cancers as a possible supplemental drug to the treatment protocols in use. The mode of action is not known. Somatostatin has been shown to cause glucose intolerance by inhibiting glucose-6-phosphate dehydrogenase (G6PD) in fish liver. Recent data generated in our laboratory indicate that it is this pathway and the transketolase reactions of the pentose cycle (PC) which are directly involved in the ribose synthesis process of pancreatic adenocarcinoma cells. In cell culture, somatostatin alone inhibited glucose carbon recycling through the PC by 5.7%, which was increased to 19.8% in combination with oxythiamine, a competitive inhibitor of transketolase. Oxythiamine produced strong apoptosis in in-vitro hosted tumor cells. We hypothesize that somatostatin- and oxythiamine-induced antiproliferative action is mediated by the inhibition of G6PD, transketolase, or both.

Zeranol, an anabolic agent produced commercially for use in cattle and sheep intended for human consumption, is noncarcinogenic, nonteratogenic, and nonmutagenic. Toxicity testing (acute, subacute, and chronic) in several species by various routes of administration reveals an extremely low toxicity, the oral rat LD50 exceeding 40 g/kg. Postmortem abnormalities of high-dose animals are attributed to the effects of the compound on the endocrine system. Both zeranol itself and zearalanone, the major Phase I metabolite in the seven species studied, are excreted in the feces and in the urine, either free or as sulfates/glucuronides. A minor urinary metabolite has been identified as taleranol, an epimer of zeranol. Both metabolites exhibit a very low order of toxicity (oral rat LD50 exceeding 10 g/kg in both cases), and both exhibit less biological activity than the parent compound. The four types of analytical methods which have been employed for the specific detection and quantitation of residues of zeranol in edible tissues are: (1) gas chromatography (detection limit = 20 ppb), (2) high-performance liquid chromatography (detection limit = 5 ppb), (3) thin-layer chromatography (detection limit = 1-3 ppb), and (4) radioimmunoassay methods (detection limit to be published). The following residue levels were determined radiometrically in tissue samples taken 45 days after implantation of cattle with 36 mg tritiated zeranol: less than or equal to 2 ppb in liver, less than or equal to 1 ppb in kidney and fat, and less than or equal to 0.2 ppb in muscle and plasma. A no-effect level (NEL) of 0.225 mg/kg was determined as the highest oral dosage of zeranol which produced no estrogenic effects in female monkeys. Based on the NEL, a tolerance level for tissue residues of zeranol was calculated as 315 ppb.

The effect of externally applied alternating electric fields on the hydrogenation of ethylene over randomly oriented zinc oxide surface has been studied. Reaction partial orders and activation energy were altered by the presence of an electric field. Variant behavior was observed, depending on the reaction temperature. At lower temperatures the effect of the field was to accelerate reaction rate and at higher temperatures, rate was decreased by the field.

Phytochrome was assayed in vivo in the rhizomes of 12 to 14-week old johnsongrass [Sorghum halapense(L.) Pers.] plants. The phytochrome levels decreased basipetally from the apex through the eighth node. The decrease was logarithmic on a dry weight basis, but less rapid on a per segment basis. On a dry weight basis, higher phytochrome measurements were obtained with samples from the interior of the rhizome than from the external regions. The far-red absorbing form of phytochrome (Pfr) was shown to be very labile at 25 C in johnsongrass rhizomes. These results provide a basis for examining photomorphogenic responses of rhizomes to light and for correlating these responses to phytochrome photophysiology.

A Boolean matrix technique is presented for the design of easily tested digital-encoding circuits to follow a flash analog-to-digital converter. The digital encoding is performed using a form of Reed-Muller network. The Reed-Muller configuration is known to be easily tested, but the design of this type of network to implement arbitrary logic equations is very difficult. The author demonstrates that the unique structure of the comparator outputs in a flash converter permits the highly testable Reed-Muller network to be designed easily with arbitrary encoding. The testability implications are discussed and a design example is presented. >

The Exxon Donor Solvent (EDS) Process has been successfully employed to liquefy coals of varying rank. Bituminous, subbituminous and lignitic coals have been processed in the continuous, integrated 40 kg day −1 Recycle Coal Liquefaction Units and 1 t day −1 Coal Liquefaction Pilot plant located at Baytown, Texas. Recent operations show that significant improvements in total liquid yield, as well as additional flexibility in product distribution, can be achieved with recycle of liquefaction bottoms. The impact of the type of coal and mode of operation on product yield and distribution as well as pilot unit operability are discussed. Specific changes in process configuration have been explored and are desirable for different coals and can be used to produce a variety of products. The implication of these recent results on defining the coal liquefaction reaction paths is discussed.

A fault-tolerant microprocessor system designed to provide digital control for an active magnetic bearing is described. This particular control problem demands significant processing power, is easily divided into relatively independent parallel tasks, and cannot tolerate controller failures. The overall system requirements and architecture are described, as is the design of the digital control module and the analog I/O board. The fault tolerance of the system is evaluated. Extensive computer simulations of system reliability models verified that the design satisfies all of the reliability requirements. Although the system was designed for a specific problem, much effort was expended to make it general enough for applications to a wide range of real-time applications. >

Various levels of intraspecific competition influenced johnsongrass [Sorghum halepense(L.) Pers.] reproduction. Increases in density, from one to eight plants per 20-cm pot, delayed for formation of rhizomes and panicles and reduced the final dry weight accumulation in these reproductive structures under greenhouse conditions. Tillering was delayed by medium density (4 plants per pot) and inhibited by the highest density (8 plants per pot). At all densities, the dry weight accumulation in reproductive structures was associated with a decrease in dry weight of the shoot material. Most of the reproductive effort was in the formation of rhizomes rather than panicles. Crowding of johnsongrass plants delayed the formation of the reproductive structures and reduced their final dry weight.

The development of an operating system that is a central component of a fault-tolerant multiprocessor is described. The operating system, while relatively simple and small, supports multitasking and multiprocessing, as well as both self-diagnostics and cross-diagnostics for fault detection. In the event of a fault, the system permits rapid reconfiguration in a manner that retains processing for the highest-priority tasks. Since the hardware needed to provide fault tolerance is available when there are no faults, the operating system can utilize this excess capacity to accomplish lower-priority tasks during normal operation. This approach yields graceful degradation in response to faults in the system components. >

Content-addressable memories may be arranged to store three-state information in a reliable and efficient manner. They can be applied to the representation of tree structures used in some graphic display applications, such as quadtrees and octrees, avoiding the need for pointers, and speeding up many operations. Examples are given for picture updating and scan conversion.