bluuebunny/crossref_metadata_2025 huggingface dataset:
Initial results from an enhanced recovery program for pediatric cardiac surgical patients
Authors: Murphy Tim , Sale Steven M. , Gonzalez Barlatay Francisco , Armstrong Catherine , Parry Andrew , Houghton Ella , Jerrom Tom , Schadenberg Alvin
Published: February 2022

Background

Over recent years, a number of enhanced recovery programs have appeared in first, adult colorectal surgery, and subsequently many other adult surgical specialties. Increasing interest in this approach to perioperative management in children culminated in the recent development of the first enhanced recovery pathway for pediatric intestinal surgery, endorsed by Enhanced Recovery after Surgery Society (ERAS®). In parallel, there has been increasing interest in the refinement of perioperative management of selected pediatric cardiac surgical patients, invariably referred to as “fast track” management. Initiatives have largely focused on duration of postoperative ventilation rather than on a much wider range of perioperative interventions to optimize recovery and ensure timely discharge after surgery. In our institution, a “Level 1” pediatric cardiac surgical center, we assembled a multidisciplinary team to design a comprehensive enhanced recovery pathway, based on ERAS® methodology, for selected cardiac surgical patients. After a lengthy period of planning, staff education, and preparation, we implemented the pathway at the end of November 2019.

Methods

We conducted a prospective audit of the perioperative management and outcomes of the first 88 patients managed according to this enhanced recovery pathway over a 25‐month period in our institution.

Results

The mean age of the patients was 5.8 years (range 0.5–17.9), and the mean weight was 22.4 kg (range 6.6–57.2). Sixty‐eight of the 88 patients were cardiopulmonary bypass cases. A total of 54% of patients received all four defined intraoperative anesthetic interventions (intravenous paracetamol, non‐steroidal anti‐inflammatory drug, antiemetic if aged more than 4 years, and use of a local anesthetic technique). A total of 89% of patients met the target extubation time of 6 h after administration of protamine. Median postoperative intensive care unit length of stay was 23.5 h (range 15.2–89.5). When compared to a historic control group, this represented a 22% reduction in median intensive care unit stay, although the total hospital length of stay remained unchanged. A total of 83% of patients met the target hospital discharge target of the fifth postoperative day.

Conclusions

These preliminary results suggest that enhanced recovery pathway implementation for selected pediatric cardiac surgical patients is feasible, with acceptable outcomes. They suggest areas for further development and the potential for wider implementation.
Native tree seedling growth and physiology responds to variable soil conditions of urban natural areas
Authors: Sonti Nancy F. , Pregitzer Clara C. , Hallett Richard A.
Published: February 2022

Soils in urban natural areas can be highly variable due to legacies of land use change that include excavation of existing soils and dumping of construction debris or other anthropogenic materials. As cities undertake large‐scale tree planting efforts to sustain and increase forest cover, understanding how urban soil quality influences native tree seedling survival and performance is important. In a greenhouse setting we examined growth and physiology of native silver maple (Acer saccharinum), black birch (Betula lenta), red oak (Quercus rubra), and Canadian serviceberry (Amalanchier canadensis) seedlings planted in soils collected from locations across New York, NY, U.S.A. The soils were collected from areas currently undergoing forest restoration, representing a range of soil nutrient quality and anthropogenic disturbance. We measured seedling survival, height growth, leaf chlorosis, and chlorophyll fluorescence for two growing seasons, after which seedlings were harvested to assess biomass allocation and foliar chemistry. Selected variables were standardized and combined to create a seedling stress index. Overall, seedlings performed best in the least disturbed urban soils and had the poorest performance in the more highly disturbed, nutrient‐poor urban soil types and a greenhouse mix. Species × soil type interactions on physiological responses indicate that tree species may not respond to urban soil conditions consistently. Consequently, matching native tree species to soil type could help optimize establishment and growth of urban forest restoration projects. Seedling stress scores from the first growing season were correlated with second year height growth for three of four species, illustrating their utility for managers.
A Dynamic Choice Model to Estimate the User Cost of Crowding with Large-Scale Transit Data
Authors: Bansal Prateek , Hörcher Daniel , Graham Daniel J.
Published: February 2022

Efficient mass transit provision should be responsive to the behaviour of passengers. Operators often conduct surveys to elicit passenger perspectives, but these can be expensive to administer and can suffer from hypothetical biases. With the advent of smart card and automated vehicle location data, operators have reliable sources of revealed preference (RP) data that can be utilized to estimate transit riders’ valuation of service attributes. To date, effective use of RP data has been limited due to modelling complexities. We propose a dynamic choice model (DCM) for population-level longitudinal RP data to address prominent challenges. In the DCM, riders are assumed to follow different decision rules (compensatory and inertia/habit) and temporal switching between decision rules based on experience-based learning is also formulated. We develop an expectation–maximization algorithm to estimate the DCM and apply our model to estimate passenger valuation of crowding. Using large-scale data of 2 months with over four million daily trips by an Asian metro, our DCM estimates show an increase of 47% in passenger’s valuation of travel time under extremely crowded conditions. Furthermore, the average passenger follows the compensatory rule on only 25.5% or fewer trips. These results are valuable for supply-side decisions of transit operators.
Survey of blood centre readiness regarding removal of DEHP from blood bag sets: The BEST Collaborative Study
Authors: Razatos Anna , Acker Jason P. , de Korte Dirk , Bégué Stéphane , Noorman Femke , Doyle Barry , Zia Majid , Min Kyungyoon ,   The Biomedical Excellence for Safer Transfusion Collaborative
Published: February 2022

Background and Objectives

Di(2‐ethylhexyl) phthalate (DEHP) must be removed from blood bag sets in Europe by 27 May 2025. DEHP is known to interact with the red blood cell (RBC) membrane, resulting in reduced haemolysis and thus prolonging shelf‐life. Current non‐DEHP alternatives result in increased haemolysis requiring reconsideration of the RBC shelf‐life. Although the immediate impact of eliminating DEHP is to the European community, the non‐DEHP movement could affect blood bag set availability globally. The purpose of this survey is to understand blood centre readiness regarding the transition to non‐DEHP blood collection and storage systems.

Materials and Methods

A 24‐question on‐line survey was completed by members of the Biomedical Excellence for Safer Transfusion Collaborative research network.

Results

Responses were obtained from 16 blood collection or processing institutions. A majority of respondents (12/16) indicated that both shelf‐life and haemolysis were equally important in selecting non‐DEHP blood bag sets. Six respondents would accept a lower RBC product shelf‐life compared to current practice. Respondents were not clear on the best non‐DEHP vinyl material or RBC storage solution. Three European blood centres indicated they have developed non‐DEHP transition plans. One challenge identified regarding the transition to non‐DEHP is the extensive validation testing that will be required.

Conclusion

Blood centres in Europe are concerned with meeting the sunset date for DEHP, considering that limited non‐DEHP blood bag and RBC storage solutions are currently available. Banning DEHP in Europe, which may have global ramifications, represents a major challenge not yet fully understood by the transfusion medicine community.
Transpelvic urethrostomy in a female dog with congenital vestibulovaginal and urethral stenosis: A case report
Authors: Chiaramonte Alessandra , Anglin Elizabeth , Takacs Joel D. , Spinelli Morgan , Clarke Dana L. , Aronson Lillian R.
Published: February 2022

Objective

To describe transpelvic urethrostomy (TPU) as a surgical technique for the successful treatment of vestibulovaginal and urethral stenosis in a 7 month old female spayed mixed‐breed dog.

Study design

Case report.

Sample population

Female spayed mixed‐breed dog with obstructive vaginal tissue present on vaginal examination.

Methods

The dog presented with a history of persistent urine dribbling, stranguria, and dysuria since birth. Vaginoscopy and fluoroscopy revealed severe vestibulovaginal and urethral stenosis. An episiotomy and partial vaginectomy were performed to remove stenotic tissue. A perineal urethrostomy was attempted from a blind‐ended pouch associated with the stenotic urethral tissue but was unsuccessful. The dog was repositioned in dorsal recumbency and a postpubic urethrostomy was performed.

Results

Six days postoperatively, incisional dehiscence occurred at the cranial aspect of the urethrostomy. The site was revised at this location using a TPU to decrease tension at the urethrostomy site. The dog recovered uneventfully with no further complications identified after surgery. Forty‐two months after surgical intervention, the dog continued to show no clinical signs.

Conclusion

Transpelvic urethrostomy may be a viable surgical alternative for dogs diagnosed with urethral stenosis.
Information and Participatory Research and Action: An Alternative to Avoid Domination and Develop Citizenship
Authors: Tavares Rosemeire B.
Published: February 2022

Objective: The research presents the effectiveness of Participatory Research and Action (PRA) specifically in information science. The main statement that motivated this qualitative study was that there is no citizenship without critical awareness. This research has the objective to demonstrate that collaborative work combined with multidirectional and interactive communication in PRA can develop critical awareness and citizenship.Methodology: The study is focused on citizens’ critical awareness development. It is based on bibliographical research, within critical thinking theoretical perspective, one of the currents contemplated by subjectivism epistemology. The study search mainly two data sources. First, Borges’ article, which presents comparative issues related to socialism and capitalism ideologies. Second, Tavares’ PhD thesis, in which PRA techniques were tested. Additionally, findings from several researches related with social development, social rights, popular participation, as well as citizen’s manipulation and domination were also collected. Data analysis were based on grounded theory principles, particularly the coding process and textual examination.Findings: Data analysis revealed three great postulations. First, lack of critical awareness and dissemination of fake news has both guided people to be manipulated, oppressed and dominated. Second, it is essential for citizen to be educated critically to deal with information that affects his life. Finally, it is possible to use PRA to develop critical awareness and citizenship. PRA promotes learning, broadens the notion of citizenship, and develops attitudes such as reading, analyzing and criticizing information, which constitutes an essential skill to developing critical awareness.
The Spring Back of Metals
Authors: Gardiner F. J.
Published: February 2022

A generalized and simplified mathematical analysis and derivation for a spring-back correction curve for pure bending is given. Extensive test data, especially for “springy” materials are shown. Qualitative reasons are given for their departure from the theoretical curve. An optimum empirical curve is plotted, showing a band of most probable values. The utilization of this general spring-back curve is described and a worked example is given. Whereas no data have been accumulated on brass and bronze materials, it is believed that these will fall into the bands set by data on aluminum, nickel-base, titanium, and ferrous alloys. It is recommended that all tooling for metals whose ratio of yield stress to elastic modulus S/E lies between 1.1 and 5.0 × 10−3 be treated in accordance with the spring-back correction factors found in Fig. 15. As soon as this ratio S/E and the material thickness have been determined a chart of tool radius R versus resultant part radius r may be prepared, e.g., Fig. 16. This chart is then used by the tool designer to specify the tool shape. Conservation of thickness and length are a necessary assumption. Whereas many sheet-metal-forming operations do not require spring-back correction, there is a large savings in “tool-development” time in those cases where the spring back is large and cumulative.
Reactor Shielding
Authors: Blizard E. P.
Published: February 2022

The problems attendant upon shielding of reactors are described briefly. The sources of radiation and their relative importance are enumerated. The interaction processes for gamma rays and neutrons are described; some discussion is given of their relative importance. The need for thermal shields in a reactor is described. Common biological shield materials are enumerated with their relative advantages and disadvantages. Some current shield designs are illustrated.
Design of Corrugated Diaphragms
Authors: Haringx J. A.
Published: February 2022

Three previous papers by the author set forth methods of calculating the rigidity of corrugated diaphragms, the stresses in the sheet material, and the nonlinearity of the relation between load and deflection. As a further step, the introduction of a few simplifying restrictions having no fundamental effect on the problem leads to the concept of a chart giving at once the dimensions a diaphragm must have so as to conform to specific requirements. An example is included by way of illustration.
Seal Leakage in the Rotary Regenerator and Its Effect on Rotary-Regenerator Design for Gas Turbines
Authors: Harper D. B.
Published: February 2022

An analysis of rotary-regenerator seal leakage is presented which predicts the leakage quantity and the variations of pressure gradient under the sealing shoe. The verifying results obtained from tests of a simulated sealing arrangement also are given. The optimum efficiency conditions of the gas-turbine cycle including leakage and pressure loss are studied; and a sample regenerator design for a specific gas-turbine plant is carried as far as the presentation of design-point curves for sizing the rotary regenerator. A method of reducing leakage is presented and the results of experimental verification are shown. Conclusions are drawn regarding the best general configuration of the rotary regenerator with respect to the leakage problem.
Mass-Transfer Cooling in a Laminar Boundary Layer With Constant Fluid Properties
Authors: Hartnett J. P. , Eckert E. R. G.
Published: February 2022

Mass transfer or transpiration cooling offers great possibilities for maintaining tolerable surface temperatures on high-speed aircraft or on turbine blades. The present study is concerned with the prediction of heat transfer, skin friction, and required coolant flows for such transpiration-cooled surfaces. The solutions presented were collected in so far as possible from the literature, and were supplemented by new calculations where required for the case of the flat plate and plane stagnation flows.
Basic Methods for Nonlinear Control-System Analysis
Authors: Stout T. M.
Published: February 2022

The important phase-plane and describing function methods are explained with the help of several simple examples. It is shown that the phase-plane method is best adapted to transient analysis of second-order systems and that the describing-function method is intended primarily for stability analysis of higher-order systems. Details and extensions of both methods are discussed in two appendixes, and a number of less important methods are mentioned.
Design and Analog-Computer Analysis of an Optimum Third-Order Nonlinear Servomechanism
Authors: Doll H. G. , Stout T. M.
Published: February 2022

Great interest has been shown recently in deliberately nonlinear control systems, including a class of programmed control systems. The design objective which distinguishes these systems is minimization of the response time for step inputs by proper automatic timing of relay operations. For a second-order relay servomechanism, the required switching relation is expressed by a curve in a two-dimensional phase plane which can be realized by a one-variable function generator in combination with linear elements. For a third-order system, the switching relation is expressed by a surface in a three-dimensional phase space and requires a two-variable function generator for its realization. The switching surface is computed in this paper for an idealized third-order positioning servomechanism having an output member characterized completely by its moment of inertia and a torque which varies linearly with time between two limits; small-signal nonlinearities such as backlash or relay threshold are neglected. An electro-optical two-variable function generator is employed in an analog-computer study of this system. For purposes of comparison, two alternative modes of control also are examined. The system using programmed control shows the expected superiority for step inputs, the advantage being greatest for small step magnitudes. For sinusoidal or random inputs, programmed control is superior when the input amplitude and/or frequency are low but exhibits some anomalous behavior for large amplitudes and/or frequencies, which result in inferior performance. Parameter tolerances for programmed control systems are somewhat less severe than anticipated.
Optimum Nonlinear Control
Authors: Oldenburger Rufus
Published: February 2022

This paper is concerned with the response of a controlled system after an initiating disturbance has died out. Such a transient is obtained, for example, when the load on a prime mover is suddenly rejected or the speed setting of an engine governor is instantly switched to a new value. It is assumed that the rate of change of the controlling variable with respect to time is bounded, and that the maximum rate of change can be obtained arbitrarily. Thus the speed of a hydraulic governor servo is limited. The best return to equilibrium (minimum over or under-swing, minimum duration of the transient, and so on) can be obtained under rather general conditions by having the servo or its equivalent travel only at maximum or zero speed. Control functions exist which give the optimum transients. These functions are nonlinear. The results of theoretical studies to enable the control designer to obtain optimum or nearly optimum transients are given here along with practical compromises. All results have been verified in the laboratory with physical devices (governors) of various kinds and automatically controlled systems.
Effect of Ambient and Fuel Pressure on Nozzle Spray Angle
Authors: De Corso S. M. , Kemeny G. A.
Published: February 2022

Diametral samples across the fuel spray at a distance of 4½ in. from the nozzle tip were obtained for ten centrifugal-type nozzles of 9 to 100-gph capacity, having nominal spray angles of 45 and 80 deg. The data were taken over a fuel-pressure range of 25 to 400 psi and for ambient pressures from 0.1 to 8 atm. These diametral spray distributions were reduced to equivalent spray-angle values which when plotted against ambient and fuel pressure provided a summary of the pressure effects on the spray angle. It was found that the spray angle decreased markedly with increasing fuel and ambient pressure. An explanation of the phenomenon is given. The equivalent spray angle was found to be a function of the product of fuel pressure drop and ambient gas density to the 1.6 power, i.e., Pγ1.6.
Operating Experience and Design Features of Closed-Cycle Gas-Turbine Power Plants
Authors: Keller Curt
Published: February 2022

This paper is the author’s third progress report in the United States on the AK closed-cycle gas turbine. The first comprehensive presentation in 1945 (1) dealt with the basic ideas and, theory, the first 2000-kw experimental plant in Zurich, and future prospects, including the use of other gases than air, such as helium, nitrogen, or carbon dioxide. The second paper in 1945 (2) gave more details and design features of different components, with special reference to machines and air heater of the first industrial 12,000-kw oil-fired plant for St. Denis and Dundee which were in the final phase of erection at that time. Projects for coal-fired plants also were discussed. This third presentation summarizes the achievements during the past five years. They are based on operation and new design experience and show the marked improvements obtained by simplifying the closed-cycle system components while keeping its basic properties. This development led the way to economical solutions in the different fields of application. Work was concentrated mainly on power-station sets up to 15 mw and for different fuels as well as on ship-propulsion plants (3). The recent accelerated development of atomic power brings a new incentive to the closed-cycle gas turbine using gases other than air as the working medium and reactor coolant.
Generalized Optimal Heat-Exchanger Design
Authors: Fax D. H. , Mills R. R.
Published: February 2022

There are many different ways of formulating the problem of the design of an optimum heat exchanger (or of any plant element or ensemble of elements) depending on what measure of performance is to be extremized and under what constraints the optimum is to be effected. A large number of such solutions exist in the literature but they often appear to have little in common, each variation in constraints apparently generating a brand new problem. Based on the use of Lagrangian multipliers, a generalized method is here developed which shows perhaps more clearly than before the interrelationship between different problems of this class. The method is particularly useful in those problems where several variables are to be optimized simultaneously. In the paper, the method is exemplified by the solution of three problems in gas-turbine regenerator design, at least two of which are believed to be new.
Practical Equipment-Replacement Economics
Authors: Scheuble P. A.
Published: February 2022

There is nothing new about the basic problems encountered when replacing manufacturing equipment since we have been doing it for thousands of years at an accelerating rate. Often, it does not take any fancy figuring to tell us that a replacement is required. The basic reasons for replacement have not changed, except that the pressure for change has increased under present-day competition and advancements in technology. We find ourselves confronted with larger capital expenditures to keep up with the drive on reducing unit cost and increasing quality. Furthermore, there is competition between various equipment proposals and other projects in their demands on capital funds. The author discusses various principles on which the economic replacement of equipment must be based.
A Combustion System for Spark-Fired Gas Engines Using Diesel Compression Ratios
Authors: Thompson L. D. , Beadle R. H. , Blake F. A.
Published: February 2022

“Jet ignition” is a combustion system which eliminates the requirement of air modulation with varying loads in a spark-fired gas engine. Jet ignition coupled with diesel compression ratios results in a versatile engine having high thermal efficiency and simple controls. Engine governing with jet ignition only requires control of the fuel as in diesel engines. The paper describes this combustion system and the background leading to its development.
Comparative Machinability of B1113—C1213—C1120 HR—C1120 CD and C1119 Steels
Authors: Bryden H. L.
Published: February 2022

A report on extensive machinability tests from which C1119 steel indicated an average tool life six times greater than that of the best B1113 and C1213 steels and nine times the tool life of the average of seven varieties of B1113 and C1213 steels investigated.
Utilization of Solar Furnaces in High-Temperature Research
Authors: Duwez Pol
Published: February 2022

This paper presents a theoretical discussion of the performances of a parabolic-type solar furnace. Maximum temperature and maximum heat flux attainable at the focus are presented for furnaces of different diameter-to-focal length ratios. It is shown that the optical quality of the parabolic reflector is the most important factor for obtaining high heat fluxes. With present-day technology, the heat flux is limited to 600 Btu/sq ft/sec, but this figure could be raised to 2300 Btu/sq ft/sec by improving the optics.
A New Way to Simplify the Steam Power Plant
Authors: Kuljian H. A. , Fadden W. J.
Published: February 2022

The purpose of this paper is to present a new approach to the ever-urgent problem of simplifying the installation and operation of steam power plants. Two alternative methods are involved, both of which combine regenerative feedwater heaters in a single shell. One integrates the closed-type heat exchangers; the other employs a new method of using open-type heat exchangers with intermediate locks. By either method, it is the conclusion of the authors that a saving in initial investment of from $10.00 to $15.00 per kilowatt will be obtained.
Universal Bearing Tester
Authors: Pigott R. J. S. , Walsh B. R.
Published: February 2022

Many bearing testers of one type or another have been devised by those who have investigated bearings. Nearly all of these, from Thurston’s old pendulum type through Kingsbury’s, have been for unidirectional load only, and therefore are limited to just one of the three classes of load we need to know about. Most of the early machines lacked the precision now required for a study of bearing conditions. It will be perceived that since the coefficient of friction may be less than 0.001, a bearing tester for say 25,000-lb bearing load must have response to less than 0.25-lb friction force if accuracy is to be better than ±1 per cent. Our initial work on bearing test machines was directed toward improving precision and sensitivity, but unidirectional loading was retained. Later it was recognized that the unidirectional load-test machine did not provide data representing dynamic loads of varying direction and magnitude. This led to the development of a rotating-load bearing test machine. The steps in this development are outlined in the paper.
Drag-Turbine Performance
Authors: Baljé O. E.
Published: February 2022

A previous treatise presented some basic considerations concerning the principal features of drag turbines. The conclusion was derived that this turbine type offers particular advantages for small accessory power units, where low bulk, simplicity, and high reliability are most desirable. This application was suggested since drag turbines exhibit peak efficiencies at low speeds; i.e., low u/cth), values where u denotes the wheel-tip speed and cth the spouting velocity of the gas. Presently available test data show peak efficiencies of about 35 per cent. Further studies reveal that higher efficiencies can be obtained so that this turbine type will not be restricted to applications where efficiencies are of secondary importance, but also will show merit in cases where an effective energy utilization is more critical. In this paper a simplified theory is presented which enables fair predictions of drag-turbine performance for compressible as well as incompressible media, accounting for the influence of design geometries on performance range and peak efficiency.
A New Automatic Dispatching System at Kansas City
Authors: Cameron D. H. , Mueller E. L.
Published: February 2022

Automatic dispatching of load carried on units of an electric system is highly desirable and contributes greatly toward successful interconnected systems operation. A new approach to the control problem was made at Kansas City in 1955. This paper outlines some of the load and equipment problems affecting control of an electric system, describes briefly the dispatching equipment designed to load units incrementally, and shows a typical operating period using the new control scheme.
Cooling Towers for Steam-Electric Stations—Selection and Performance Experiences
Authors: Larinoff M. W.
Published: February 2022

Cooling towers are an important component in many of today’s large steam-electric generating plants and the power industry is looking forward to an even greater use of this equipment in the future. Certain problems and difficulties presently confronting the tower purchaser and user are reviewed in the light of the purchaser’s requirements and the user’s operating experiences. Maintenance cost data for 50 cooling towers totaling 2,600,000 gpm capacity are presented. The effect of tower thermal-performance deficiency on station capability and heat rate is discussed. The paper is concluded with a prediction of what the cooling-tower industry has to look forward to from the power industry as regards future cooling-tower sizes for both nuclear and conventional, fuel-fired power plants.
Design Basis for Cascade-Type Positional Servomechanisms
Authors: Lees Sidney , Blaschke T. C.
Published: February 2022

A design basis, previously developed for multiloop positional servomechanisms, has been extended to cascade-type systems. The design basis attempts to co-ordinate specifications, dynamic characteristics, interferences, and uncertainties from a consideration of the generation of torques by the system. The limitations of the system performance are distinguished from component characteristics. The concept of frequency-dependent coefficients is applied to the lead modifier damping model, the lag modifier, viscous damping model, and to the lag modifier, lead modifier damping model. It is shown that the performance may be understood from knowledge of second-order systems. Estimates of useful values of the parameters for each model are confirmed by analog studies.
Future Developments of the High-Speed Diesel Engine
Authors: Chatterton Ernest
Published: February 2022

This paper has the main objective of exploring the lines of development which appear to offer greatest possibilities for the reduction of size and weight of the diesel engine. The author examines the increases in power output from a given size of cylinder which result from the combination of a diesel engine and exhaust-driven gas turbine operating with high degrees of supercharge. He discusses the limitations and draws conclusions as to the type of engine best suited to such developments.
Quantum kicks near a Cauchy horizon
Authors: Juárez-Aubry Benito A. , Louko Jorma
Published: February 2022

We analyze a quantum observer who falls geodesically toward the Cauchy horizon of a (1 + 1)-dimensional eternal black hole spacetime with the global structure of the non-extremal Reissner–Nordström solution. The observer interacts with a massless scalar field, using an Unruh–DeWitt detector coupled linearly to the proper time derivative of the field, and by measuring the local energy density of the field. Taking the field to be initially prepared in the Hartle–Hawking–Israel (HHI) state or the Unruh state, we find that both the detector's transition rate and the local energy density generically diverge on approaching the Cauchy horizon, respectively, proportionally to the inverse and the inverse square of the proper time to the horizon, and in the Unruh state the divergences on approaching one of the branches of the Cauchy horizon are independent of the surface gravities. When the outer and inner horizons have equal surface gravities, the divergences disappear altogether in the HHI state and for one of the Cauchy horizon branches in the Unruh state. We conjecture, on grounds of comparison with the Rindler state in 1 + 1 and 3 + 1 Minkowski spacetimes, that similar properties hold in 3 + 1 dimensions for a detector coupled linearly to the quantum field, but with a logarithmic rather than inverse power-law divergence.
Peak Loads Associated With High-Impact Physical Activities in Children
Authors: Fassett Zach , Jagodinsky Adam E. , Thomas David Q. , Williams Skip M.
Published: February 2022

Physical activities involving impact loading are important for improving bone strength and mineral density in children. There is little research quantifying impact loads associated with various high-impact activities. Purpose: Examine the magnitude of peak ground reaction forces (pGRF) across different jumping activities in children. Methods: Eight children between 8 and 12 years (9.63 [1.49] y; 1.42 [0.08] m; 33.69 [4.81] kg), performed 5 trials of a broad jump, countermovement jump, jumping jack, leap jump, and drop jump on a force plate. The pGRF were determined during the landing phase of each activity and expressed in units of body weight (BW). A repeated-measures analysis of variance was employed to assess differences in pGRF across activities. Results: Drop jump exhibited the greatest pGRF (3.09 [0.46] BW) in comparison with the vertical jumping jack (2.56 [0.21] BW; P < .001) and countermovement jump (2.45 [0.22] BW; P = .001), as well as the horizontal broad jump (2.25 [0.2] BW; P = .003), and leap jump (2.01 [0.1] BW; P = .002). Conclusion: Peak loads between 2 and 3.1 BW were exhibited across each jump activity, which is moderate compared with magnitudes in most jump interventions seeking to improve bone health. All conditions except drop jump exhibited loading <3 BW, suggesting these activities may not produce sufficient loads to improve bone outcomes.
Genetic Signatures from Adaptation of Bacteria to Lytic Phage Identify Potential Agents To Aid Phage Killing of Multidrug-Resistant Acinetobacter baumannii
Authors: Oyejobi Greater Kayode , Xiong Dongyan , Shi Mengjuan , Zhang Xiaoxu , Yang Hang , Xue Heng , Ogolla Faith , Wei Hongping
Published: February 2022

Bacteriophages have proven very useful as alternative therapeutic agents in combating multidrug-resistant bacterial infections; however, bacterial resistance to phages threatens their use. In this study, we showed a new strategy of leveraging genetic signatures that accompany phage resistance in bacteria to predict agents that can be used with lytic phages to combat multidrug-resistant
Acinetobacter baumannii
.
Sex, military occupation and rank are associated with risk of anterior cruciate ligament injury in tactical-athletes
Authors: Aguero Aubrey D , Irrgang J J , MacGregor A J , Rothenberger S D , Hart J M , Fraser J J
Published: February 2022

Introduction

Anterior cruciate ligament (ACL) injury is common within the US military and represents a significant loss to readiness. Since recent changes to operational tempo, there has not been an analysis of ACL injury risk. The aim of this retrospective cohort study was to evaluate military occupation, sex, rank and branch of service on ACL injury risk in the US military from 2006 to 2018.

Methods

The Defense Medical Epidemiology Database was queried for the number of US tactical athletes with International Classification of Diseases diagnosis codes 717.83 (old disruption of ACL), 844.2 (sprain of knee cruciate ligament), M23.61 (other spontaneous disruption of ACL) and S83.51 (sprain of ACL of knee) on their initial encounter. Relative risk and χ2statistics were calculated to assess sex and military occupation effects on ACL injury. A multivariable negative binomial regression model evaluated changes in ACL injury incidence with respect to sex, branch of service and rank.

Results

The study period displayed a significant decrease in the ACL injury rate at 0.18 cases per 1000 person-years or relative decrease of 4.08% each year (p<0.001) after averaging over the main and interactive effects of sex, rank and branch of service. The interaction effect of time with sex indicated a steeper decline in the incidence in men as compared with women. The risk of ACL injury by sex was modified by rank. The incidence among military personnel varied by occupation.

Conclusion

Despite the decline among tactical athletes over time, rates of ACL injury remain much higher than the general US population. Sex, rank, branch of service and military occupation were found to be risk factors for ACL injury. It is critical for policy makers to understand the salient risk factors for ACL injury to guide proactive measures to prevent injury.
Unintended pregnancy, induced abortion and abortion care-seeking experiences among adolescents in Kinshasa, Democratic Republic of Congo: a cross-sectional study
Authors: Fatusi Adesegun , Riley Taylor , Kayembe Patrick K , Mabika Crispin
Published: February 2022

Objectives

To estimate age-specific abortion incidence and unintended pregnancy in Kinshasa, Democratic Republic of Congo and compare care experiences between adolescents (15–19 years) and older women (20–49 years).

Design

We used the age-specific variant of the Abortion Incidence Complications Method to estimate abortion and unintended pregnancy, with data from three primary sources: Health Facility Survey (n=361) provided postabortion care (PAC) caseloads; Prospective Morbidity Survey (n=1031) provided the age distribution and characteristics of women presenting for PAC and Health Professional Survey (n=115) provided an estimate of the proportion of abortions resulting in facility-based treatment of complications. Bivariate (χ2, t-test) and multivariable (binary logistic regression, Cox proportional hazard) analyses were used to compare abortion care experiences.

Setting

Health facilities proving PAC in Kinshasa.

Participants

Women who presented to PAC facilities with abortion complications and their care providers.

Primary and secondary outcome measures

The primary measures were abortion incidence and proportion of pregnancies unintended. The secondary measures were the odd of reporting specific abortion care experiences.

Results

Adolescents had an estimated 27 590 induced abortions, constituting 18.8% of abortions in Kinshasa in 2016. Adolescents had the lowest abortion rate among women less than 35 years (55.2/1000 women) but the highest rate among ever sexually active women (138.4/1000) and recently sexually active women (167.2/1000). Also, adolescents had the highest abortion ratio (82.4/100 live births), proportion of pregnancies unintended (80%) and proportion of unintended pregnancies ending in abortion (49%). Compared with older women, adolescents had higher odds of reporting pregnancy unintendedness (adjusted OR, AOR 1.36, 95% CI 1.75 to 2.24), seeking abortion at later than first trimester (AOR 1.34, 95% CI 1.09 to 1.63) and from non-medical professionals (AOR 1.68, 95% CI 1.31 to 2.14), and not using contraceptives before pregnancy (AOR 2.23, 95% CI 2.77 to 3.43) or postabortion (AOR 2.46, 95% CI 1.87 to 3.29).

Conclusions

Interventions are needed to reduce unintended pregnancy among adolescents in Kinshasa and improve their abortion care experiences.
Design of the HEM-POWR study: a prospective, observational study of
real-world treatment with damoctocog alfa pegol in patients with haemophilia
A
Authors: Sanabria Martin , Álvarez Román María Teresa , Castaman Giancarlo , Janbain Maissaa , Matsushita Tadashi , Meijer Karina , Oldenburg Johannes , Friedl Sabine , Reding M T
Published: February 2022

Introduction

Haemophilia A is a rare bleeding disorder caused by defects in
coagulation factor VIII (FVIII). Damoctocog alfa pegol (BAY 94–9027,
Jivi, Bayer, Germany) is a site-specifically PEGylated,
extended-half-life, recombinant FVIII, approved for use in previously
treated patients (PTPs) aged ≥12 years with haemophilia A. However, a
real-world evidence regarding routine clinical use of damoctocog alfa
pegol is limited.

Methods and analysis

HEM-POWR is a multinational, multicentre, non-interventional,
prospective, postmarketing cohort study evaluating the effectiveness and
safety of real-world treatment with damoctocog alfa pegol. Estimated
enrolment is ≥200 PTPs with haemophilia A, receiving damoctocog alfa
pegol (on-demand, prophylaxis or intermittent prophylaxis (as per local
label)), observed for 36 months. Primary outcomes are total bleeding
events and annualised bleeding rate; secondary outcomes include
long-term safety, joint health, pharmacokinetics, patient-reported
outcomes (PROs) from validated questionnaires and perioperative
haemostasis. Where applicable, reasons for switching to damoctocog alfa
pegol, choice of treatment regimen and dose will also be captured.
Exploratory and descriptive statistical analyses will be performed, and
will be stratified by parameters including, but not limited to,
prophylaxis regimen and haemophilia severity. Patients can record bleeds
and consumption in electronic (e) Diaries, ePROs, and can access
non-promotional study information (videos explaining study procedures)
via an online patient portal. Optionally, patients can enrol in the
LIFE-ACTIVE substudy designed to investigate the relationship between
activity (measured by the ActiGraph CP Insight watch) and effectiveness
parameters collected from HEM-POWR.

Ethics and dissemination

Study approval was obtained by local independent ethics committees
and authorities in participating study centres across Europe, the
Americas and Asia. Informed consent from patients or their legal
representative is a requirement for participation. The study results
will be submitted for publication in a peer-reviewed scientific journal
and presented at scientific conferences.

Trial registration numbers

NCT03932201, EUPAS26416.

Protocol version and date

V.1.2, 27 September 2019.
Protection levels of N95-level respirator substitutes proposed during the COVID-19 pandemic: safety concerns and quantitative evaluation procedures
Authors: Ballard David H , Dang Audrey J , Kumfer Benjamin M , Weisensee Patricia B , Meacham J Mark , Scott Alex R , Ruppert-Stroescu Mary , Burke Broc A , Morris Jason , Gan Connie , Hu Jesse , King Bradley , Jammalamadaka Udayabhanu , Sayood Sena , Liang Stephen , Choudhary Shruti , Dhanraj David , Maranhao Bruno , Millar Christine , Bertroche J Tyler , Shomer Nirah , Woodard Pamela K , Biswas Pratim , Axelbaum Richard , Genin Guy , Williams Brent J , Meacham Kathleen
Published: February 2022

Objective

The COVID-19 pandemic has precipitated widespread shortages of filtering facepiece respirators (FFRs) and the creation and sharing of proposed substitutes (novel designs, repurposed materials) with limited testing against regulatory standards. We aimed to categorically test the efficacy and fit of potential N95 respirator substitutes using protocols that can be replicated in university laboratories.

Setting

Academic medical centre with occupational health-supervised fit testing along with laboratory studies.

Participants

Seven adult volunteers who passed quantitative fit testing for small-sized (n=2) and regular-sized (n=5) commercial N95 respirators.

Methods

Five open-source potential N95 respirator substitutes were evaluated and compared with commercial National Institute for Occupational Safety and Health (NIOSH)-approved N95 respirators as controls. Fit testing using the 7-minute standardised Occupational Safety and Health Administration fit test was performed. In addition, protocols that can be performed in university laboratories for materials testing (filtration efficiency, air resistance and fluid resistance) were developed to evaluate alternate filtration materials.

Results

Among five open-source, improvised substitutes evaluated in this study, only one (which included a commercial elastomeric mask and commercial HEPA filter) passed a standard quantitative fit test. The four alternative materials evaluated for filtration efficiency (67%–89%) failed to meet the 95% threshold at a face velocity (7.6 cm/s) equivalent to that of a NIOSH particle filtration test for the control N95 FFR. In addition, for all but one material, the small surface area of two 3D-printed substitutes resulted in air resistance that was above the maximum in the NIOSH standard.

Conclusions

Testing protocols such as those described here are essential to evaluate proposed improvised respiratory protection substitutes, and our testing platform could be replicated by teams with similar cross-disciplinary research capacity. Healthcare professionals should be cautious of claims associated with improvised respirators when suggested as FFR substitutes.
Changes in arterial stiffness indices during a single haemodialysis session in end-stage renal disease population: a systematic review and meta-analysis protocol
Authors: Fortier Catherine , Obeid Hasan , Paré Mathilde , Garneau Charles-Antoine , Sidibé Aboubacar , Boutouyrie Pierre , Agharazii Mohsen
Published: February 2022

Introduction

Patients with end-stage renal disease are at higher risk of cardiovascular morbidity and mortality, a risk mediated in part by increased aortic stiffness. Arterial stiffness is assessed at different anatomical locations (central elastic or peripheral muscular arteries) using a variety of mechanical biomarkers. However, little is known on the robustness of each of these mechanical biomarkers following a haemodynamic stress caused by a single haemodialysis (HD) session.

Methods and analysis

A systematic review has been designed and reported in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols. A targeted search strategy applicable in key databases (PubMed, Embase, the Cochrane Library, Web of Science and grey literature) is constructed to search articles and reviews from inception to 16 October 2020. Only articles of studies conducted with adults under chronic HD for kidney failure, with repeated measures of arterial stiffness metrics (pulse wave velocity, Augmentation Index, arterial distensibility or stiffness) following a before-and-after design surrounding a HD session will be selected. The screening process, data extraction and assessment of risk bias will be done by two independent pairs of reviewers. Meta-analysis will enable adjustments for potential confounders and subgroup analyses will be performed to discriminate changes in arterial stiffness metrics from elastic, muscular or global arterial territories.

Ethics and dissemination

This study does not require ethical approval. Findings will be submitted for publication to relevant peer-reviewed journals and will be presented at profession-specific conferences.

PROSPERO registration number

CRD42020213946.