Independent Carriers Research Articles

Integrating the independent granular charge carriers into microbial fuel cell: From performance to mechanism analysis

The mutual benefits between electroactive bacteria (EAB) and non-EAB promote bioenergy recovery in microbial fuel cell (MFC), while competition between functional and non-functional bacteria on electrodes hinders further performance improvement. Introducing non-electrode conductive carriers into MFC may reduce contact resistance and alleviate interspecies competition. In this study, three-dimensional spherical biochar (BC) granules as independent microbial and charge carriers are introduced into anode chamber of an MFC without direct contact with the electrode (carbon cloth, CC) creating CC-BC-MFC. CC-BC-MFC achieves superior power density of 15 ± 1.4 W m−3 compared to CC-MFC (12 ± 1.4 W m−3) and CC/BC-MFC (10 ± 1.2 W m−3, where BC directly contacts CC). Higher effluent quality highlights the outstanding contribution of adequate biomass in effective containment treatment. Smaller internal resistance and higher coulombic efficiency are obtained in CC-BC-MFC by relieving microbial competition at anode. Syntrophic growth between Geobacter (69.4 %) and Methanosarcina (98 %) is established on BC in CC-BC-MFC, with high expression of Geobacter-associated pili genes and acetotrophic and CO2-reducing methanogenic genes associated with methanogens. Therefore, incorporating BC as flexible and independent charge carriers can reduce internal resistance, provide adequate habitat, alleviate microbial competition at anode, and offer a feasible strategy for MFC in wastewater treatment.

A Bilevel Approach for Compensation and Routing Decisions in Last-Mile Delivery

In last-mile delivery logistics, peer-to-peer logistic platforms play an important role in connecting senders, customers, and independent carriers to fulfill delivery requests. As the carriers are not under the platform’s control, the platform has to anticipate their reactions while deciding how to allocate the delivery operations. Indeed, carriers’ decisions largely affect the platform’s revenue. In this paper, we model this problem using bilevel programming. At the upper level, the platform decides how to assign the orders to the carriers; at the lower level, each carrier solves a profitable tour problem to determine which offered requests to accept, based on her own profit maximization. Possibly, the platform can influence carriers’ decisions by determining also the compensation paid for each accepted request. The two considered settings result in two different formulations: the bilevel profitable tour problem with fixed compensation margins and with margin decisions, respectively. For each of them, we propose single-level reformulations and alternative formulations where the lower-level routing variables are projected out. A branch-and-cut algorithm is proposed to solve the bilevel models, with a tailored warm-start heuristic used to speed up the solution process. Extensive computational tests are performed to compare the proposed formulations and analyze solution characteristics. Funding: The research of E. Fernandez was partially funded through the Spanish Ministerio de Ciencia y Tecnología and European Regional Development Funds (ERDF) [Grant MTM2019-105824GB-I00]. The research of C. Archetti, M. Cerulli, and I. Ljubić was partially funded by CY Initiative of Excellence, France [Grant “Investissements d’Avenir ANR-16-IDEX-0008”]. Supplemental Material: The online appendix is available at https://doi.org/10.1287/trsc.2023.0129 .

Non-line-of-sight optical wireless communication system enabled by wavefront shaping for multi-user indoor access.

In this Letter, we experimentally investigate a non-line-of-sight (NLOS) optical wireless communication (OWC) system that utilizes wavefront shaping techniques to realize simultaneous data transmission for multiple users. Wavefront shaping techniques are employed to address the issue of low intensity of diffusely reflected light at the receiver in NLOS scenarios for indoor high-speed access. To achieve communication path planning and tracing for two different users in free-space optical communication, the pixels of the spatial light modulator (SLM) are divided into two halves to separately manipulate the wavefront of two independent data carriers centered at different wavelengths. The maximum received optical power can be effectively improved by more than 15 dB with the wavefront shaping technique. To avoid power enhancement of non-target wavelength, the wavelength difference of two different users is experimentally studied. The difference in power enhancement ratio (DPER) is increased with the wavelength difference, and 14.95 dB DPER is obtained with a 10 nm wavelength difference. Under the aforementioned wavelength planning strategy, successful transmission and reception of 2 × 160 Gbit/s 16-QAM signals for two users with coherent detection is achieved using wavelengths of 1550 and 1560 nm in an indoor access scenario.

Beam steering using delays generated from an optical OAM mode shifting recirculating loop

This paper investigates the performance of generated delays from an orbital angular momentum mode shifting recirculating delay loop (OAM-SL) in simulation using Kirchhoff-Fresnel diffraction (KFD) and the delays applicability for RF signal beam steering applications. OAM-SL is a novel structure that has been recently reported to produce multiple delayed signal replicas on independent OAM carriers using a single compact system. The objective of this research is to explore the impact of several limiting factors on the quality of OAM-SL delays for beam steering applications, such as where there is (i) displacement of the OAM mode shifter, (ii) displacement of the center of the OAM mode demultiplexer at the loop output, and (iii) the limited resolution. The methodology includes: (i) simulating the beam propagation using KFD, (ii) producing the output as a coherent summation of the recirculating beams, and (iii) characterizing the SCR by dividing the power of the recirculating beam (ρ) on its OAM mode by the power accumulated from the other recirculating beams. Our findings show that delays generated from a system with lin=−30, lshift=+1, and a resolution of 1024 pixels can steer a 100 MHz signal at a steering angle of 11.5° in a four antenna system with 0.1° error if loop alignment is perfect. Also, for steering the 100 MHz signal in an eight antenna system, we analyze the system assuming the system loss can be compensated, and a similar result of 0.1° error is obtained. Additionally, we report the beam steering performance at 23.6° and 36.8°.

Ecologies of quantification in waste management: Landfilling, e-waste recycling, and car breaking

Quantification has become a privileged form of knowing and vehicle of governance. Anthropological critique has demonstrated that a view of numbers as independent carriers of meaning is untenable; instead, numbers should be conceptualized as being part of relations and temporalities, opening space for shifts in understanding. Proposing the perspective of ‘ecologies of quantification’, we acknowledge the wider notion of ecology that accommodates materiality, cognition, and experience, and acknowledges that the constituents of the relations are always in a process of becoming. We put waste management at the centre of our interest to explore the ways quantification attempts to conquer arguably one of the unruliest domains of contemporary social life. Based on our collaborative ethnographic research on the management of municipal solid waste, discarded electrical and electronic devices, and junked cars in Czechia, we point to problems emerging when numbers become stripped of their relations. Our research sheds light on experience in the process of quantification and demonstrates that there are multiple ways to know quantity.

Spherical Nucleic Acid‐Amplified Digital Flow Cytometric Bead Assay for the Ultrasensitive Detection of Protein and Exosome†

Comprehensive SummaryMost conventional digital bioassays rely on the use of fully‐sealed microchambers as independent units to compartmentalize the target molecules and the signal generation reaction, which require specialized equipment or proprietary reagents/consumables. Herein, we report a microchamber‐free and spherical nucleic acid (SNA)‐amplified digital flow cytometric bead assay (dFBA) for ultrasensitive protein and exosome analysis with simple workflows, easily accessible instruments/reagents, and high discriminating ability towards the fluorescence‐positive and fluorescence‐negative beads. In this dFBA, microbeads are employed as independent carriers to anchor the single target molecule‐initiated signal amplification reaction, avoiding the use of sealed droplets or microwell microchambers. Meanwhile, antibody‐functionalized SNAs (FSNAs) with a high density of DNA probes act as a bridge for efficiently amplified target‐to‐DNA signal conversion, which allows the use of DNA‐based rolling circle amplification (RCA) as the fluorescence signal amplification technique to quantify non‐nucleic acid targets. Even a single target‐induced on‐bead RCA and fluorescence enriching are sufficient to make the target‐loaded bead bright enough to be clearly discriminated from the negative ones just by use of a most common flow cytometer (FCM). This dFBA has successfully realized the digital analysis of ultralow levels of protein and exosome biomarkers, enlarging the toolbox of digital bioassays for clinical applications.

Psychological constructs of the character of professional military men in the works of A.S. Pushkin

Understanding the sources of formation of the character of professional military personnel is an important task of pedagogical psychology, since it makes it possible to make the process of developing the personality of a serviceman in the pedagogical process of a military university more effective. An important source for the formation of character traits of a professional military officer is literary sources, artistic means of influencing personal structures. The subject of research in the article is the psychological properties of the individual, characteristic of the heroes of the works of Alexander Sergeevich Pushkin, who, according to the author's artistic conception, were professional soldiers. The writer's artistic work in a complex way constructs on the pages of his works the psychological features characteristic of professional military men. The author's knowledge in the work is based on the most popular literary works of A.S. Pushkin using a system-activity and axiological approach to understanding the development of personality. The author notes that a comprehensive study of the images of the domestic military intelligentsia from artistic heroes who have become independent carriers of psychological properties characteristic of domestic officers is an urgent scientific task for modern psychological knowledge, therefore this contradiction must be resolved. The theoretical generalizations obtained as a result of the study can be useful in organizing educational work with cadets, as well as in carrying out other forms of work with military personnel.

The (amazing) super-maze

The entropy of the three-charge NS5-F1-P black hole in Type IIA string theory comes from the breaking of N1 F1 strings into N1N5 little strings, which become independent momentum carriers. In M theory, the little strings correspond to strips of M2 brane that connect pairs of parallel M5 branes separated along the M-theory direction. We show that if one takes into account the backreaction of the M-theory little strings on the M5 branes one obtains a maze-like structure, to which one can add momentum waves. We also show that adding momentum waves to the little strings gives rise to a momentum-carrying brane configuration — a super-maze — which locally preserves 16 supercharges. We therefore expect the backreaction of the super-maze to give rise to a new class of horizonless black-hole microstate solutions, which preserve the rotational symmetry of the black-hole horizon and carry sqrt{5/6} of its entropy.

High speed radiation tolerant optical links based on coarse wavelength division multiplexing

The upgrade of CERN’s accelerator complex requires improved beam instrumentation systems that will generate an increased volume of data to be transferred from the radiation areas to the back-end. A solution that increases the throughput of already deployed fibers, with minimal increase of the system complexity, consists in implementing the coarse wavelength division multiplexing (CWDM) technique where independent optical carriers at properly spaced wavelengths are multiplexed into a single fiber. In this paper we describe the CWDM Link project, whose scope is to design and build a high-speed radiation-tolerant optical link based on four CWDM channels. We will also provide details of commercially-available CWDM components and their radiation resistance.

Fast hyperspectral single-pixel imaging via frequency-division multiplexed illumination.

Hyperspectral imaging that detects 3D spectra-spatial information has been used in a wide range of applications. Among reported techniques, multiplexed spectral imaging with a single-pixel detector provides as a photon-efficient and low-cost implementation; however, the previous spectral modulation schemes are mostly complicated and sacrifice the imaging speed. Here, we propose a fast and compact hyperspectral single-pixel imaging technique based on programmable chromatic illumination. A multi-wavelength LED array modulated by independent carriers achieves stable and accurate spectral modulation up to MHz in a frequency-division multiplexed manner, hence allowing the full use of the spatial light modulation speed. Additionally, we propose a multi-channel deep convolutional autoencoder network to reconstruct hyperspectral data from highly-compressed 1D measurement. Experimental reconstructions of 12 spectral channels and 64 × 64 pixels are demonstrated for dynamic imaging at 12 fps image rate. The proposed imaging scheme is highly extensible to a wide spectrum range, and holds potential for portable spectral imagers in low-light or scattering applications.

Asset ownership & incentives to undertake non‐contractible actions: The case of trucking

AbstractFirms must continually adjust their operations and those of their supply chain members in response to a continually evolving external environment. Many of these modifications are non‐contractible in that firms cannot devise and enforce contracts on these behaviors. In this research, we extend property rights theory of the firm (PRTF) by suggesting that small entrepreneurs’ ownership of assets used to perform delegated tasks does not always incentivize small entrepreneurs to undertake non‐contractible actions (NCAs) as assumed by canonical PRTF. We argue that the ability of asset ownership to incentivize small entrepreneurs to undertake NCAs will be muted when undertaking NCAs reduces small entrepreneurs’ productivity. We test our hypotheses by examining how trucking companies’ use of independent contractors affected the rate at which they improved compliance with different types of safety rules following a major regulatory change. Consistent with our arguments, we find that the use of independent contractors slowed carriers’ rate of firm‐wide improvement on compliance with hours‐of‐service and vehicle maintenance rules relative to driving safety rules. These results, which remain after extensive robustness testing, have important implications for theory and practice.

DEVELOPMENT OF A METHOD FOR ASSIGNING PRIVATE LOCOMOTIVES TO TRAINS

Purpose. Ukraine is currently in the process of reforming the railway transportations market, which is related to the implementation of European Union Directives to its legislation. As a result of these reforms, the opening of the railway transportation market for carriers independent of Ukrzaliznytsia is envisaged. In such conditions, the problem of ensuring access of rolling stock to the receiving and departure tracks and the elimination of conflict situations with train and shunting movements of rolling stock of Ukrzaliznytsia can be solved by passing trains of independent carriers according to a tight schedule. One of the use areas of private locomotives is servicing of points of mass loading or unloading of goods. One of the tasks that arises in this case is to improve the methods of assigning private locomotives to the threads of the train schedule. Methodology. The research is performed based on the methods of organization of operational work of railways and methods of linear programming. Findings. The paper considers the problem of improving the methods of calculating the size of the working fleet of locomotives. Based on the analysis of possible conditions of interaction between Ukrzaliznytsia JSC and private carriers, it is determined that one of the possible options for using private transport companies at the stage of implementation of their services will be the service of points of mass loading or unloading of goods. In the course of the research a method of determining the number of locomotives by reducing this problem to an optimization problem of purpose was developed. An example of solving the problem of determining the required working fleet of locomotives to service the transportation of grain cargo sent to the port by shipping routes and developing schedules of their turnover is given. The number of locomotives needed to service transportations was set and the procedure for their connection to trains developed. Originality. The research improves the methods of assignment locomotives to the threads of the train schedule based on the use of linear programming methods. Practical value. The results of the work allow us to assess the needs of the working fleet of locomotives in the open market of railway transportations for independent carriers.

3D printing process for textile composites

The geometry of a braid influences its mechanical properties directly. On the other hand, the path of the carriers dictates the geometry of the braid. In traditional braiding machines, the carriers move along a fixed path, via horngears, which cannot be changed during the braiding process. This limitation does not allow braiding with variable geometry parameters along its axis, such as variable thickness and variable cross-sections. This paper presents a braiding machine design allowing a completely independent carrier movement. This process is analogous to 3D printing where layer-by-layer deposition produces a final part. In our case, controlling the position of each intertwining yarn will create a 3D braid. Each carrier can move without affecting the position of its neighbors allowing an easier and total control on the position and morphology of each intertwining yarn. A novel horngear design is proposed. The horngears are independently driven. They occupy the bedplate area in a hexagonal compact arrangement. The carrier path can be divided into multiple pre-defined unitary displacements. Driven by the horngears, the carrier follows these successive unitary displacements. A prototype of the braiding machine has been developed and tested with three independent carriers. As a first step, a flat braid with three yarns is produced. In the second step, a braid with a variable cross section is produced: a flat braid turning into yarn twisting. This proof of concept opens-up the possibility of 3D-printing textile composites with tailorable mechanical properties.

Tetrairon(II) extended metal atom chains as single-molecule magnets.

Iron-based extended metal atom chains (EMACs) are potentially high-spin molecules with axial magnetic anisotropy and thus candidate single-molecule magnets (SMMs). We herein compare the tetrairon(ii), halide-capped complexes [Fe4(tpda)3Cl2] (1Cl) and [Fe4(tpda)3Br2] (1Br), obtained by reacting iron(ii) dihalides with [Fe2(Mes)4] and N2,N6-di(pyridin-2-yl)pyridine-2,6-diamine (H2tpda) in toluene, under strictly anhydrous and anaerobic conditions (HMes = mesitylene). Detailed structural, electrochemical and Mössbauer data are presented along with direct-current (DC) and alternating-current (AC) magnetic characterizations. DC measurements revealed similar static magnetic properties for the two derivatives, with χMT at room temperature above that for independent spin carriers, but much lower at low temperature. The electronic structure of the iron(ii) ions in each derivative was explored by ab initio (CASSCF-NEVPT2-SO) calculations, which showed that the main magnetic axis of all metals is directed close to the axis of the chain. The outer metals, Fe1 and Fe4, have an easy-axis magnetic anisotropy (D = -11 to -19 cm-1, |E/D| = 0.05-0.18), while the internal metals, Fe2 and Fe3, possess weaker hard-axis anisotropy (D = 8-10 cm-1, |E/D| = 0.06-0.21). These single-ion parameters were held constant in the fitting of DC magnetic data, which revealed ferromagnetic Fe1-Fe2 and Fe3-Fe4 interactions and antiferromagnetic Fe2-Fe3 coupling. The competition between super-exchange interactions and the large, noncollinear anisotropies at metal sites results in a weakly magnetic non-Kramers doublet ground state. This explains the SMM behavior displayed by both derivatives in the AC susceptibility data, with slow magnetic relaxation in 1Br being observable even in zero static field.

DEVELOPMENT OF TECHNICAL FACILITIES AND TECHNOLOGIES FOR TRANSPORTATION OF GRAIN CARGO IN UKRAINE BY LARGE TRANSPORT

Purpose. The purpose of the article is to study the development of technologies and technical means of transportation of grain cargoes by rail in Ukraine. Methodology. The research was carried out on the basis of methods for analyzing the state of development of the processes of transportation of grain cargo in Ukraine and in other states, as well as analysis of literature sources, statistical reports on the export of grain, the state of railways. Results. The paper deals with the history of development and the problem of organizing cargo transportation to seaports by independent carriers. The needs for reducing the cost of transportation of grain cargo are determined. It has been established that when solving this issue, one should use the achievements of domestic scientists, as well as the know-how of advanced developed countries in the implementation of grain transportation. The study shows the potential for applying foreign experience, taking into account the peculiarities of the local specifics of the development of political and geographic conditions and the existing infrastructure. Scientific novelty. The scientific novelty of the work lies in the fact that it provides a study of methods for organizing the transportation of grain cargo by rail, used in the world and an analysis of the possibility of their application in Ukraine. Practical significance. The practical significance of the work lies in the fact that it can be used for further research, development of a state development program and assistance to the agro-industrial industry of Ukraine, in the analysis of the construction of new elevators, the introduction of new transportation technologies, as well as for assessing the costs associated with various logistics schemes for grain delivery to seaports.

Insect Bacterial Symbiont-Mediated Vitellogenin Uptake into Oocytes To Support Egg Development.

Many insect species, such as aphids, leafhoppers, planthoppers, and whiteflies harbor obligate bacterial symbionts that can be transovarially transmitted to offspring through the oocytes of female insects. Whether obligate bacterial symbionts can carry important molecules/resources to the embryos to support egg development is still unknown. Here, we show that the vitellogenin (Vg) precursor of rice leafhopper Nephotettix cincticeps is biosynthesized by the fat body, secreted into the hemolymph and subsequently cleaved into the 35- and 178-kDa subunits, whereas only the 178-kDa subunit is taken up by the leading end of oocytes in a receptor-dependent manner or moves into the posterior pole of the terminal oocyte in association with obligate bacterial symbiont "Candidatus Nasuia deltocephalinicola" (hereafter Nasuia) in a receptor-independent manner. Furthermore, the 178-kDa Vg subunit can directly interact with a surface channel molecule (porin) on the envelope of Nasuia, allowing Vg to enter bacterial cytoplasm. Thus, Vg can hitchhike the ancient oocyte entry path of Nasuia, the common obligate symbiont of leafhoppers. Knocking down a Nasuia growth-related protein expression or treatment with porin antibody strongly prevents the ability of Nasuia to carry Vgs into oocytes and impair insect egg development. Nasuia-carried Vgs provide at least 20% of the total Vgs in the developing eggs. We anticipate that the bacterial symbiont-mediated Vg uptake into oocytes to support efficient egg development may be a common pattern shared by many insects.IMPORTANCE Many insects harbor obligate bacterial symbionts that can be vertically transmitted to offspring by female insects through eggs. Here, we report that leafhopper vitellogenin (Vg) recognizes and binds a surface channel molecule (porin) on the envelope of obligate bacterial symbiont Nasuia, which potentially induces the opening of porin channels for Vg to access the cytoplasm of Nasuia Thus, Vg can exploit bacterial symbionts as the independent carriers into the oocytes. Such Nasuia-carried Vg contents support efficient insect egg development. Thus, our findings indicate that insects have evolved strategies to exploit the symbionts for carrying additional Vgs to guarantee optimal insect reproduction.

The two-fold diffusion process for proton uptake reaction in BCFZY e-/H+/O2- triple conductor measured by electrical conductivity relaxation

For materials as BaCo0.4Fe0.4Zr0.1Y0.1O3-δ with three independent mobile charge carriers, hole, oxygen ion, and proton, a peculiar twofold diffusion and transition from hydration to hydrogenation in proton uptake are investigated by electrical conductivity relaxation method in this work. At 700 °C, the water incorporation reaction would happen in the formation of both hydration and hydrogenation. The hydration reaction would happen at the sacrifice of oxygen vacancy, and then, the incorporated proton diffuses from outer layer to the inner bulk. But due to much higher chemical diffusion coefficient of proton than oxygen vacancy, the highly mobile protons are charge compensated by holes, instead of waiting for the less mobile oxygen vacancy, and thus causes the speeding increased hole concentration, i.e., increased conductivity. So in the hydration reaction, the decoupled diffusion of proton and oxygen vacancy would result in a non-monotonic conductivity relaxation curve, i.e., twofold diffusion. After that, the proton uptake reaction would transit to hydrogenation, as total decreased conductivity in a monotonic curve.

Incoherent Laser Heterodyned Long-Reach 60-GHz MMWoF Link With Volterra Filtered 16-QAM OFDM Beyond 13 Gbps

By remotely heterodyning two independent laser carriers, the long-reach 60-GHz millimeter-wave-over-fiber (MMWoF) link is demonstrated for the Volterra series filtered quadrature amplitude modulation orthogonal frequency division multiplexing (QAM-OFDM) transmission with nonlinear noise suppression, which enables 13-Gbps data delivery through 50-km single-mode fiber (SMF) and 3-m free-space links. A wavelength tunable colorless laser diode transmits the Volterra filter equalized QAM-OFDM data to remotely couple with a localized single-mode laser carrier at the optical receiving end of the MMWoF system. Such an incoherently coupled dual-mode carrier facilitates the optical single-carrier modulation to suppress chromatic dispersion induced power fading effect of the SMF transmitted QAM-OFDM data. The 2nd+3rd-order nonlinear noise induced by direct modulation, heterodyne conversion, and phase fluctuation of the incoherently coupled dual-mode carrier is corrected with the Volterra filter equalization to upgrade the decoded signal-to-noise ratio (SNR) by >2 dB. After remotely heterodyning the downstream and the localized carriers with mutual incoherence in between, the 16-QAM OFDM transmission at a data rate up to 13.2 Gbps is successfully delivered over 3-m wireless link, which reveals the FEC certificated error vector magnitude of 14.1%, SNR of 17 dB, and bit error rate of 1.7 × 10−3.

Out-of-Network Air Ambulance Bills: Prevalence, Magnitude, and Policy Solutions.

Policy Points Out‐of‐network air ambulance bills are a type of surprise medical bill and are driven by many of the same market failures behind other surprise medical bills, including patients’ inability to choose in‐network providers in an emergency or to avoid potential balance billing by out‐of‐network providers.The financial risk to consumers is high because more than three‐quarters of air ambulances are out‐of‐network and their prices are high and rising. Consumers facing out‐of‐network air ambulance bills have few legal protections owing to the Airline Deregulation Act's federal preemption of state laws.Any federal policies for surprise medical bills should also address surprise air ambulance bills and should incorporate substantive consumer protections—not just billing transparency—and correct the market distortions for air ambulances. ContextOut‐of‐network air ambulance bills are a growing problem for consumers. Because most air ambulance transports are out‐of‐network and prices are rising, patients are at risk of receiving large unexpected bills. This article estimates the prevalence and magnitude of privately insured persons’ out‐of‐network air ambulance bills, describes the legal barriers to curtailing surprise air ambulance bills, and proposes policies to protect consumers from out‐of‐network air ambulance bills.MethodsWe used the Health Care Cost Institute's 2014‐2017 data from three large national insurers to evaluate the share of air ambulance claims that are out‐of‐network and the prevalence and magnitude of potential surprise balance bills, focusing on rotary‐wing transports. We estimated the magnitude of potential balance bills for out‐of‐network air ambulance services by calculating the difference between the provider's billed charges and the insurer's out‐of‐network allowed amount, including the patient's cost‐sharing. For in‐network air ambulance transports, we calculated the average charges and allowed amounts, both in absolute magnitude and as a multiple of the rate that Medicare pays for the same service.FindingsWe found that less than one‐quarter of air ambulance transports of commercially insured patients were in‐network. Two‐in‐five transports resulted in a potential balance bill, averaging $19,851. In the latter years of our data, in‐network rates for transports by independent (non‐hospital‐based) carriers averaged $20,822, or 369% of the Medicare rate for the same service.ConclusionsBecause the states’ efforts to curtail air ambulance balance billing have been preempted by the Airline Deregulation Act, a federal solution is needed. Owing to the failure of market forces to discipline either prices or supply, out‐of‐network air ambulance rates should be benchmarked to a multiple of Medicare rates or, alternatively, air ambulance services could be delivered and financed through an approach that combines competitive bidding and public utility regulation.

Role of Membrane Tension Sensitive Endocytosis and Rho GTPases in the Uptake of the Alzheimer's Disease Peptide Aβ(1-42).

Intraneuronal accumulation of amyloid-β (Aβ) is an early pathological signum of Alzheimer’s disease, and compartments of the endolysosomal system have been implicated in both seeding and cell–cell propagation of Aβ aggregation. We have studied how clathrin-independent mechanisms contribute to Aβ endocytosis, exploring pathways that are sensitive to changes in membrane tension and the regulation of Rho GTPases. Using live cell confocal microscopy and flow cytometry, we show the uptake of monomeric Aβ(1-42) into endocytic vesicles and vacuole-like dilations, following relaxation of osmotic pressure-induced cell membrane tension. This indicates Aβ(1-42) uptake via clathrin independent carriers (CLICs), although overexpression of the bar-domain protein GRAF1, a key regulator of CLICs, had no apparent effect. We furthermore report reduced Aβ(1-42) uptake following overexpression of constitutively active forms of the Rho GTPases Cdc42 and RhoA, whereas modulation of Rac1, which is linked to macropinosome formation, had no effect. Our results confirm that uptake of Aβ(1-42) is clathrin- and dynamin-independent and point to the involvement of a new and distinct clathrin-independent endocytic mechanism which is similar to uptake via CLICs or macropinocytosis but that also appear to involve yet uncharacterized molecular players.