Primary Transport Research Articles

Comparative Physiology and Genomics of Hydrogen-Producing Vibrios.

The Hyf-type formate hydrogen lyase (FHL) complex was first proposed based on sequence comparisons in Escherichia coli in 1997 (Andrews et al. in Microbiology 143:3633-3647, 1997). The hydrogenase in the Hyf-type FHL was estimated to be a proton-translocating energy-conserving [NiFe]-hydrogenase. Although the structure of FHL is similar to that of complex I, silent gene expression in E. coli has caused delays in unveiling the genetic and biochemical features of the FHL. The entire set of genes required for Hyf-type FHL synthesis has also been found in the genome sequences of Vibrio tritonius in 2015 (Matsumura et al. in Int J Hydrog Energy 40:9137-9146, 2015), which produces more hydrogen (H2) than E. coli. Here we investigate the physiological characteristics, genome comparisons, and gene expressions to elucidate the genetic backgrounds of Hyf-type FHL, and how Hyf-type FHL correlates with the higher H2 production of V. tritonius. Physiological comparisons among the seven H2-producing vibrios reveal that V. porteresiae and V. tritonius, grouped in the Porteresiae clade, show greater capacity for H2 production than the other species. The structures of FHL-Hyp gene clusters were closely related in both Porteresiae species, but differed from those of the other species with the presence of hupE, a possible nickel permease gene. Interestingly, deeper genome comparisons revealed the co-presence of nickel ABC transporter genes (nik) with the Hyf-type FHL gene only on the genome of the Porteresiae clade species. Therefore, active primary Ni transport might be one of the key factors characterizing higher H2 production in V. tritonius. Furthermore, the expression of FHL gene cluster was significantly up-regulated in V. tritonius cells stimulated with formate, indicating that formate is likely to be a control factor for the gene expression of V. tritonius FHL in a similar way to the formate regulon encoding the E. coli FHL.

Challenges in Sub-Kilometer Grid Modeling of the Convective Planetary Boundary Layer

At multi-kilometer grid scales, numerical weather prediction models represent surface-based convective eddies as a completely sub-grid one-dimensional vertical mixing and transport process. At tens of meters grid scales, large-eddy simulation models, explicitly resolve all the primary three-dimensional eddies associated with boundary-layer transport from the surface and entrainment at the top. Between these scales, at hundreds of meters grid size, is a so-called grey zone in which the primary transport is neither entirely sub-grid nor resolved, where explicit large-eddy models and sub-grid boundary-layer parameterization models fail in different ways that are outlined in this review article. This article also reviews various approaches that have been taken to span this gap in the proper representation of eddy transports in the sub-kilometer grid range using scale-aware approaches. Introduction of moisture with condensation in the eddies expands this problem to that of handling shallow convection, but similarities between dry and cloud-topped convective boundary layers can lead to some unified views of the processes that need to be represented in convective boundary-layers which will be briefly addressed here.

Geologic processes in marine “muddy” sediments

Marine muds, or “muddy” sediments, represent a broad range of sediments containing a mix of clay and silt size components, often with some smaller amount of sand sized and larger material. Sediments characterized by these broad definitions comprise most of the modern global seafloor, except for areas proximal to terrigenous inputs, such as continental shelves and glacial margins, which can receive and retain a higher proportion of coarser sediment. Beyond the coastal zone, the distribution of marine sediments is driven by a combination of geological, biological, and physical oceanographic processes that themselves are a response to variations in environmental conditions (e.g., global climate, nutrient availability, tectonics, terrestrial erosion). At the local scale, sediment source variation, seafloor bathymetry, primary transport and near-bed currents, resuspension and reworking, and bioturbation contribute to the short- and long-term geologic nature of marine muds. The structure, quantitative compositional descriptions, and physical properties of marine muds from several environments will be compared and the techniques used to analyze them will be presented. New methods that may facilitate an improved understanding of the role and importance of muddy seafloor and shallow sub-seafloor sediments in influencing the acoustic environment will be highlighted.

Weakening of the biological pump induced by a biocalcification crisis during the early Toarcian Oceanic Anoxic Event

Severe environmental changes during the early Toarcian (Early Jurassic; ∼182 Ma), comprising global warming, elevated pCO2, intensified continental weathering and a high amplitude sea level rise, led to the genesis of a Toarcian Oceanic Anoxic Event (T-OAE), expressed by the widespread occurrence of organic carbon (OC)-rich sediments (black shales) forming on anoxic epicontinental shelves. Here, we show that during the T-OAE black shales in some depocenters have formed under rather low organic carbon accumulation rates (OCAR). We explain this observation by a reduced export efficiency of OC to the sediment, caused by a drastic decline in the abundance of mineral ballast, due to a major biocalcification crisis and the demise of calcareous nannoplankton. The reduction of mineral ballast led to slowing of the sinking speed of particulate organic matter, which thus became more prone to biodegradation. A major sea level rise, accompanying the T-OAE, was associated with retrograding shorelines and shift of depocenters away from the basin centers to more coastal areas. This might have reduced nutrient fluxes to the distal depocenters and diminished surface productivity and export flux in the central basin. Moreover, during sea level rise reduced input of clastics from adjacent landmasses may have led to a decline in organic carbon dilution. A decline in both abundance and size is documented for faecal pellets in core FR-210-078 from the Lorraine Basin, substantiating the scenario of reduced marine primary productivity and organic matter transport efficiency. Accordingly, during the T-OAE low OCAR are here interpreted to reflect a weakening of the biological pump. These new data substantiate the role of organic matter preservation as major factor controlling the formation of black shales during the T-OAE. The Toarcian marine transgression led to an increase in the extent of shelf areas, accompanied by an expansion of oxygen-deficient conditions that favored the preservation of organic matter in shelf sediments. Consequently, despite low OCAR, net C-burial in shelf sea sediments increased during the T-OAE, which may have acted as negative feedback mechanism that caused global cooling in the aftermath of the event.

From your kidneys to your eyes: lessons from computational kidney models

Purpose: The purpose of this review is to describe computational models that have been developed for studying kidney function and howthese models may be adapted to study the eyes. Methods: We derive equations for modeling solute andwater transport across epithelial cell membranes in the kidney. These equations describe mass conservation, as well membrane transport via cotransporters, exchangers, and primary active transport. Results: Wedescribe howcomputational models of renal transport have been applied to investigate kidney function in physiological and pathophysiological conditions. Conclusion: The computational models herein described for the kidney may be adapted to study ocular functions and dysfunction.

Small-molecule eRF3a degraders rescue CFTR nonsense mutations by promoting premature termination codon readthrough.

The vast majority of people with cystic fibrosis (CF) are now eligible for CF transmembrane regulator (CFTR) modulator therapy. The remaining individuals with CF harbor premature termination codons (PTCs) or rare CFTR variants with limited treatment options. Although the clinical modulator response can be reliably predicted using primary airway epithelial cells, primary cells carrying rare CFTR variants are scarce. To overcome this obstacle, cell lines can be created by overexpression of mouse Bmi-1 and human TERT (hTERT). Using this approach, we developed 2 non-CF and 6 CF airway epithelial cell lines, 3 of which were homozygous for the W1282X PTC variant. The Bmi-1/hTERT cell lines recapitulated primary cell morphology and ion transport function. The 2 F508del-CFTR cell lines responded robustly to CFTR modulators, which was mirrored in the parent primary cells and in the cell donors’ clinical response. Cereblon E3 ligase modulators targeting eukaryotic release factor 3a (eRF3a) rescued W1282X-CFTR function to approximately 20% of WT levels and, when paired with G418, rescued G542X-CFTR function to approximately 50% of WT levels. Intriguingly, eRF3a degraders also diminished epithelial sodium channel (ENaC) function. These studies demonstrate that Bmi-1/hTERT cell lines faithfully mirrored primary cell responses to CFTR modulators and illustrate a therapeutic approach to rescue CFTR nonsense mutations.

Identifying Eastern US Atmospheric River Types and Evaluating Historical Trends

AbstractAn atmospheric river (AR) is the primary moisture transport forcing in the Western United States, making ARs the predominant producer of extreme precipitation events in this region. A growing body of evidence suggests similar impacts for the Central and Eastern US This study determines the most prominent types of ARs in the Central and Eastern US study domain through the implementation of a machine learning methodology. Self‐organizing maps (SOMs) are leveraged to determine what “flavors” of ARs exist in the study domain. Four atmospheric river detection criteria are utilized to investigate the variability AR types. Mann‐Kendall trend analyses on AR strength and size are produced to evaluate changes over the study period. The results confirm extratropical cyclones as the most common driver of ARs, however, limited kinematic forcing can also instigate the development of AR events. Results show coastal cyclones and lee‐side cyclones are responsible for producing the strongest ARs. The trend analysis results suggest that ARs associated with Nor'easters and ARs originating in the Gulf of Mexico are exhibiting increasing trends in intensity and/or size. Increasing moisture transport by mature cyclones across the Central and Eastern US have important implications for flooding in highly populated corridors. Areas of concern include the Northeast and Southeast US, while localized enhancement of rainfall is seen along the eastern and southern slopes of the Appalachian Mountains. In addition to the physical findings, this research highlights the importance and sensitivity of statistically significant results to the specific atmospheric river detection criteria that was leveraged.

Determining nitrate sources in storm runoff in complex urban environments based on nitrogen and oxygen isotopes.

Urban storm runoff, as the primary transport medium for nutrients entering urban rivers, contributes to urban water contamination. Accurate source identification is critical for controlling water pollution. Although some studies have used nitrate isotopic composition (δ15N-NO3- and δ18O-NO3-) to identify nitrate (NO3--N) in urban storm runoff, the relatively low frequency of collecting samples in surface runoff within a single functional area hinders the understanding of spatial variations and dynamic process of NO3--N sources over the runoff process. This study investigated the nitrogen (N) concentrations and analyzed dynamic changes of NO3--N sources in surface runoff in different urban functional areas, drainage pipeline runoff, and channels during the complete runoff process in Wuxi, east China. The results showed that N concentrations in pipeline runoff and channels were higher than those in surface runoff, indicating that high concentration of N pollutants were accumulated in drainage pipelines. Information of δ15N-NO3- and δ18O-NO3- suggested that the main NO3--N source varied between runoff stages. NO3--N contribution from atmospheric deposition decreased in the order: surface runoff (57%) > residential pipeline runoff (25%) > channels (14%), while the opposite trend was observed for the contributions from sewage, increasing from 10%, 26% to 39%. In urban storm runoff, more sewage, fertilizers, and soil N were carried into the surface runoff after 30% of cumulative runoff ratio and carried into pipeline runoff in the initial 25% of cumulative runoff ratio in the residential area. As the first attempt to identify nitrate sources over the cumulative runoff in different urban functional areas, this work expands our understanding of the primary nitrate source in urban storm runoff. The findings provide important insights for developing strategies to mitigate non-point source water pollution.

Modeling of natural gas self-diffusion in the micro-pores of organic-rich shales coupling sorption and geomechanical effects

A significant amount of the natural gas in shale formations is contained in the micro- and mesopores as dissolved (absorbed) phase and on the surfaces of associated microcracks as (adsorbed) phase. The transport of natural gas in such confined spaces is primarily governed by self-diffusion as could be deduced from Knudsen number. Self-diffusion is governed by the pressure and the space confinement. In this study, realistic kerogen structures possessing both tortuous micropores and larger microcracks were formed and used to assess self-diffusion behavior during the depletion of shale reservoirs through some comprehensive molecular simulation workflow. Analysis of the transport modes revealed transition self-diffusion as the primary transport mechanism in these micropores. The sorption behavior and the mechanical properties were analyzed and incorporated to derive a transition diffusion model that is sensitive to changes in the pore pressure and the stress field. The proposed model was compared and validated against similar work in the literature. The results showed that during a typical production span, a pressure drop influences the sorption profile, the net overburden stress on the pores, and the mean free path, altering the magnitude of self-diffusivity. The calibrated pore scale model produced decent predictive ability with a relative error of 2.5–16%. The implications of structure tortuosity, sorption profile, and pore pressure on the effective diffusion coefficient and gas desorption are discussed in depth. This work provides a novel methodology for studying the effect of coupled multiphysics processes on methane transport in a realistic kerogen geometry, which could be used to calibrate a suitable pore scale model for upscaled reservoir simulation applications and accurate assessment of reservoir dynamics and ultimate recovery.

The Nutraceuticals as Modern Key to Achieve Erythrocyte Oxidative Stress Fighting in Osteoarthritis.

Osteoarthritis (OA), the most common joint disease, shows an increasing prevalence in the aging population in industrialized countries. OA is characterized by low-grade chronic inflammation, which causes degeneration of all joint tissues, such as articular cartilage, subchondral bone, and synovial membrane, leading to pain and loss of functionality. Erythrocytes, the most abundant blood cells, have as their primary function oxygen transport, which induces reactive oxygen species (ROS) production. For this reason, the erythrocytes have several mechanisms to counteract ROS injuries, which cause damage to lipids and proteins of the cell membrane. Oxidative stress and inflammation are highly correlated and are both causes of joint disorders. In the synovial fluid and blood of osteoarthritis patients, erythrocyte antioxidant enzyme expression is decreased. To date, OA is a non-curable disease, treated mainly with non-steroidal anti-inflammatory drugs and corticosteroids for a prolonged period of time, which cause several side effects; thus, the search for natural remedies with anti-inflammatory and antioxidant activities is always ongoing. In this review, we analyze several manuscripts describing the effect of traditional remedies, such as Harpagophytum procumbens, Curcumin longa, and Boswellia serrata extracts, in the treatments of OA for their anti-inflammatory, analgesic, and antioxidant activity. The effects of such remedies have been studied both in in vitro and in vivo models, considering both joint cells and erythrocytes.

A kinetic model for multicomponent gas transport in shale gas reservoirs and its applications

An accurate gas transport model is of vital importance to the simulation and production optimization of unconventional gas reservoirs. Although great success has been achieved in the development of single-component transport models, limited progress has been made in multicomponent systems. The major challenge of developing non-empirical multicomponent gas transport models lies in the absence of the quantification of the concentration impact on the fluid dynamic properties. To fill such a gap, this work presents a comprehensive transport model for multicomponent gas transport in shale and tight reservoirs. In developing the model, we first conducted molecular dynamic simulations to qualitatively understand the differential release of hydrocarbons from unconventional shale and tight reservoirs. It is found that the gas slippage, differential adsorption, and surface diffusion are the primary transport mechanisms in the working range of Knudsen number during reservoir production. Based on the molecular dynamic study, a quantitative transport model has been developed and validated, which extends existing models from single-component systems to multiple-component systems. The kinetic theory of gases is adopted and modified to model the multicomponent slippage effect. A generalized Maxwell–Stefan formulation with extended Langmuir adsorption isotherm is used to model the multicomponent surface diffusion process. The accuracy of the proposed model is above 90% for low to moderate Knudsen numbers in modeling the differential release phenomenon in unconventional reservoirs.

Integrating Station-Area Development with Rail Transit Networks: Lessons from Japan Railway in Tokyo

Rail transit is a primary transport mode in Tokyo and has become the backbone of its urban development. Tokyo rail transit networks consist of the subway in the central area, private railways in the suburban area, and Japan Railway (JR) in both central and suburban areas. Prior research revealed that JR has better coordination of transit node functions and station-area development than subway and private railway stations, but how Tokyo's JR station-area development integrates with its network growth is less explored. This work investigates how JR station-area development grows in tandem with network expansion, by revisiting different historical phases. The results show that, in the beginning of the twentieth century, JR connected major urban nodes in both central and suburban Tokyo, and therefore became the skeleton of Tokyo's transit systems. During the post-earthquake and post-war period, central subway and suburban private railways gradually met JR on the Yamanote line, enabling the major interchange stations to develop into urban centers. In the 1960s, JR increased its services to alleviate passenger congestion and undertook grade separation projects to reduce conflicts with road networks. The 1987 JR privatization marked a turning point of massive station-area redevelopment. JR station areas have been transformed from underutilized industrial land into high-density commercial use, and major JR stations were comprehensively replanned for identity and place-making. After a centennial development, JR stations have become important interchange and express-service nodes on Tokyo transit networks with intensive land use and different urban functions. The Tokyo JR case can provide insights for metropolitan cities on how to integrate rail transit infrastructure with station-area development, including matching critical nodes in transit networks with urban functions and high-density land use and connecting these urban functions through express line services.

Optimizing the fugacity model to select appropriate remediation pathways for perfluoroalkyl substances (PFASs) in a lake

Increased anthropogenic activities have caused contamination of perfluoroalkyl substances (PFASs) in lakes worldwide. However, how to remediate their contamination remains unclear. In this study, a heavily polluted lake, Baiyangdian Lake in China, was selected to investigate current PFASs levels in multimedia, stimulate their transport fate based upon an optimized fugacity model, and finally identify appropriate remediation pathways. From 2008–2019, the average concentrations of PFASs in the lake increased approximately 7–40 times in the environment and biota. Spatially, with continuous import of perfluorohexane sulfonate (PFHxS) and perfluorooctanoic acid (PFOA), barring fish, a noticeable north-south difference was distinguished in the PFASs composition in multimedia from the lake. Based on the optimized fugacity model simulation, the water phase was the primary transport path (~76.5%) for PFASs, with a total flux of 333 kg y-1. Compared with bioaccumulation fluxes in submerged plants (6.2 kg y-1), emerged plants (2.6 kg y-1), and fish (1.1 kg y-1), the exchange flux of PFASs between water and sediment remained high (~94 kg y-1). Considering remediation cost, sediment cleaning is currently the most cost-effective pathway, while harvesting submerged plant could be a promising pathway in the future. This study provides a basis for remediating PFASs-polluted lakes on a global scale.

Modeling of Safety Basis Events in the VTR

The Versatile Test Reactor (VTR) is a fast spectrum test reactor currently being developed in the United States under the direction of the U.S. Department of Energy, Office of Nuclear Energy. Safety analysis of the conceptual VTR design is being performed using the SAS4A/SASSYS-1 fast reactor safety analysis code with a model representing the reactor core, primary and secondary heat transport systems, reactor vessel auxiliary cooling system, and reactor protection system. The system’s response and safety performance are being evaluated for a wide spectrum of event initiators and accident sequences. This paper presents an overview of the activities that are ongoing in support of the modeling and analysis of safety basis events (SBEs) in the VTR, including the VTR SAS4A/SASSYS-1 model development, an overview of the SAS4A/SASSYS-1 verification and validation efforts, and a summary of key model development activities to improve the predictive capability of the code. A summary of the results and an analysis of several key SBEs are also presented. VTR authorization from the U.S. Department of Energy will require transient simulations that are demonstrated to be accurate.

Helicopter inter-hospital transfer for patients undergoing extracorporeal membrane oxygenation: a retrospective 12-year analysis of a service system

BackgroundPatients undergoing extracorporeal membrane oxygenation (ECMO) are critically ill and show high mortality. Inter-hospital transfer of these patients has to be safe, with high survival rates during transport without potentially serious and life-threatening adverse events. The Swiss Air-Rescue provides 24-h/7-days per week inter-hospital helicopter transfers that include on-site ECMO cannulation if needed. This retrospective observational study describes adverse events of patients on ECMO transported by helicopter, and their associated survival.MethodsAll patients on ECMO with inter-hospital transfer by helicopter from start of service in February 2009 until May 2021 were included. Patients not transported by helicopter or with missing medical records were excluded. Patient demographics (age, sex) and medical history (type of and reason for ECMO), mission details (flight distance, times, primary or secondary transport), adverse events during the inter-hospital transfer, and survival of transferred patients were recorded. The primary endpoint was patient survival during transfer. Secondary endpoints were adverse events during transfer and 28-day survival.ResultsWe screened 214 ECMO-related missions and included 191 in this analysis. Median age was 54.6 [IQR 46.1–62.0] years, 70.7% were male, and most patients had veno-arterial ECMO (56.5%). The main reasons for ECMO were pulmonary (46.1%) or cardiac (44.0%) failure. Most were daytime (69.8%) and primary missions (n = 100), median total mission time was 182.0 [143.0–254.0] min, and median transfer distance was 52.7 [33.2–71.1] km. All patients survived the transfer. Forty-four adverse events were recorded during 37 missions (19.4%), where 31 (70.5%) were medical and none resulted in patient harm. Adverse events occurred more frequently during night-time missions (59.9%, p = 0.047). Data for 28-day survival were available for 157 patients, of which 86 (54.8%) were alive.ConclusionAll patients under ECMO survived the helicopter transport. Adverse events were observed for about 20% of the flight missions, with a tendency during the night-time flights, none harmed the patients. Inter-hospital transfer for patients undergoing ECMO provided by 24-h/7-d per week helicopter emergency medical service teams can be considered as feasible and safe. The majority of the patients (54.8%) were still alive after 28 days.

Use of a Short, In‐Class, Free Response Activity to Assess Student Understanding of Core Concepts of the Cell Membrane in an Undergraduate Physiology Course

Students in an upper division, stand‐alone animal physiology course at Missouri Western State University are required to have completed a freshman‐level introductory cell biology course and a sophomore‐level genetics course as prerequisites. These prerequisite courses include discussion of the eukaryotic cell membrane and basic properties and functions of the membrane. However, many students remember the basic information about membrane structure but have difficulty relating that structure to membrane function and related topics in our physiology course, including vesicular transport, primary and secondary active transport, osmosis, and current flow across the membrane. To gain a better understanding of what students recall about the cell membrane before covering membrane structure and function in class, students were given an open‐ended prompt, “What do you know about the structure and function of the animal cell membrane?” The students were allowed to work in small groups or alone, and could generate their response as drawings, written statements, or both. They were given 10 minutes to construct a response. These student responses were analyzed using the conceptual framework for the “cell membrane” core concept recently published by Michael and Modell (Adv Physiol Educ 2019). This activity was repeated 2 weeks after finishing discussing of the cell membrane. Prior to covering this content in class, 100% (19 out of 19) submissions included a drawing or description of the cell membrane as a phospholipid bilayer, and 84% of submissions included integral and peripheral membrane proteins. Similar percentages of students included these concepts in the post‐coverage assessment. However, other components of the “cell membrane” conceptual framework were included much less frequently or not at all prior to covering the content in class, but improved dramatically afterwards. In the pre‐assessment, only 11% of responses included solute concentration gradients or selective permeability, while 70% of responses in the post‐assessment included this concepts. In the pre‐assessment less than 10% mentioned vesicular transport, receptors, or channel proteins; after covering the content in class, these topics were included by 15%, 45%, and 35% of student responses, respectively. This quick activity provides valuable information about what students recall from prior coursework and what concepts need to be revisited before moving into more detailed discussion of cell membrane function. When used in addition to objective exam or assignment questions, this free‐response activity can also provide a complementary view of student understanding of core concepts of the cell membrane.

Can Helicopters Solve the Transport Dilemma for Patients With Symptoms of Large-Vessel Occlusion Stroke in Intermediate Density Areas? A Simulation Model Based on Real Life Data.

BackgroundThis modeling study aimed to determine if helicopters may optimize the transportation of patients with symptoms of large vessel stroke in “intermediate density” areas, such as Denmark, by bringing them directly to the comprehensive stroke center.MethodsWe estimated the time for the treatment of patients requiring endovascular therapy or intravenous thrombolysis under four configurations: “drip and ship” with and without helicopter and “bypass” with and without helicopter. Time delays, stroke numbers per municipality, and helicopter dispatches for four helicopter bases from 2019 were obtained from the Danish Stroke and Helicopter Registries. Discrete event simulation (DES) was used to estimate the capacity of the helicopter fleet to meet patient transport requests, given the number of stroke codes per municipality.ResultsThe median onset-to-needle time at the comprehensive stroke center (CSC) for the bypass model with the helicopter was 115 min [interquartile range (IQR): 108, 124]; the median onset-to-groin time was 157 min (IQR: 150, 166). The median onset-to-needle time at the primary stroke center (PSC) by ground transport was 112 min (IQR: 101, 125) and the median onset-to-groin time when primary transport to the PSC was prioritized was 234 min (IQR: 209, 261).A linear correlation between travel time by ground and the number of patients transported by helicopter (rho = 0.69, p < 0.001) indicated that helicopters are being used to transport more remote patients. DES demonstrated that an increase in helicopter capture zone by 20 min increased the number of rejected patients by only 5%.ConclusionsOur model calculations suggest that using helicopters to transport patients with stroke directly to the CSC in intermediate density areas markedly reduce onset-to-groin time without affecting time to thrombolysis. In this setting, helicopter capacity is not challenged by increasing the capture zone.

Outcomes of Pediatric Patients in Secondary Transport to Tertiary Hospital: A Retrospective Observational Study.

Emergency medical service (EMS) providers play an important role in determining which hospital to choose. To date, there is no evidence-based guideline to support their decisions, except for major trauma cases. Secondary transport is considered when a patient needs further investigation or treatment after primary transport, but this can delay treatment and put patients at unnecessary risk. The objective of this study was to investigate the outcomes of pediatric secondary transport patients to tertiary hospitals. This was a citywide population-based observational study conducted in Kobe, Japan. We reviewed the EMS registry to identify secondary transport patients younger than 19 years and investigated their clinical characteristics. We excluded cases of unknown hospital destinations, nontransported cases, and major trauma patients who followed a different protocol for a hospital destination. The primary endpoint was the hospital outcome 12 hours after transport. Because there was no link between the EMS patient transport data and the hospital medical records, a probabilistic linkage was performed to obtain the hospital outcomes. Patients who required secondary transport were compared with patients transported directly to tertiary hospitals. A total of 13,720 pediatric patients were transported from the field by Kobe EMS between January 2013 and December 2015. Among them, 81 pediatric patients (0.6%) required secondary transport to tertiary hospitals within 24 hours of the primary transport, whereas a total of 3673 patients (27%) were transported directly to tertiary hospitals. Despite no apparent difference in prehospital severity, secondary transport patients were associated with higher hospitalization rates and a need for critical care compared with those who had direct transport. Seizure was the most common reason for the use of secondary transport, and 89% of the seizure patients were hospitalized after undergoing secondary transport; minor trauma was the second most common reason for the use of secondary transport, and 53% of the patients were hospitalized. In this study, the characteristics of the secondary transport patients and hospital outcomes revealed a heterogeneity in pediatric prehospital transport. It is recommended that the development of pediatric EMS destination guidelines cover children's diverse conditions. Further studies are required, and linkages between prehospital and hospital data will help promote a better understanding of appropriate hospital destinations.

Reliability-based inspection and maintenance planning of a nuclear feeder piping system

Inspection and maintenance (I&M) is essential to ensure the integrity of feeder pipes, which are parts of the primary heat transport system in a nuclear power plant. The pipes are subject to flow accelerated corrosion (FAC), which can compromise the integrity of the piping system and lead to high repair costs. We explore the opportunity for improving I&M strategies while ensuring that the system still maintains an acceptable level of reliability. To this aim, a reliability-based planning framework is proposed, in which every pipe in the system meets the minimum thickness requirement at a specified annual probability. With this planning framework we can a) evaluate the performance of any I&M strategy constrained to a fixed reliability criterion, without requiring this strategy to be specifically designed for such a criterion; and b) find an I&M strategy optimized for this reliability level using a heuristic description of the strategy space. We demonstrate the framework with a case study, where the wall thinning due to FAC is modeled as a Gamma process with uncertain parameters. We compare the expected life-cycle cost of multiple strategies for I&M of a feeder system with 480 pipes. The proposed approach is compared with an I&M strategy currently used by the industry, which highlights the efficiency of the proposed optimization method.

Методика подготовки экспериментальных данных для информационно-интеллектуальной системы проектирования сетей лесовозных дорог

The article describes a technique for obtaining experimental data for the purpose of optimal distribution of the forest transport network on a specific terrain model. Particular attention was paid to the issue of the operability of primary forest transport routes, in particular, the requirements for the strength of trunk lines, which is of fundamental importance when establishing the optimal distance between long-term roads. The operability of the trunk lines was experimentally investigated, while the scheme of the movement of tractors along the ring was used. Based on experimental data, certain values of track depth, relative humidity, density and the number of impacts depending on the number of passes were obtained. In the course of the experimental study, functional dependences of the increase in the depth of the track on the number of passages were established and calculated, taking into account the physical and mechanical properties of forest soils. During the tests, some fundamental differences were recorded in the process of track formation during the movement of wheeled and tracked tractors. It is important for the development of measures to reduce the seasonality of forest transport, especially during the autumn-spring thaw. Comparative tests of tracked and wheeled tractors when they move along a reinforced track have shown that a reinforced track when moving a wheeled tractor is able to withstand a significantly greater number of passes than when moving a tracked tractor. For the statistical evaluation of the experiments carried out, it was determined what errors could be caused by replacing the parameter with its point estimate. Analysis of statistical processing of the observation results showed that all the series, as a rule, correspond to the law of normal definition, which is determined by the ratio of the symmetry and kurtosis indicators to their average errors. These relations are determined within the limits of permissible deviations, therefore, asymmetry and kurtosis in this case do not matter significantly.