Concentric Layers Research Articles

3D relationship between hierarchical canal network and gradient mineralization of shark tooth osteodentin.

Osteodentin is a dominant mineralized collagenous tissue in the teeth of many fishes, with structural and histological characteristics resembling those of bone. Osteodentin, like bone, comprises osteons as basic structural building blocks, however, it lacks the osteocytes and the lacuno-canalicular network (LCN), which are known to play critical roles in controlling the mineralization of the collagenous matrix in bone. Although numerous vascular canals exist in osteodentin, their role in tooth maturation and the matrix mineralization process remain poorly understood. Here, high resolution micro-computed tomography (micro-CT) and focused ion beam-scanning electron microscopy (FIB-SEM) were used to obtain 3D structural information of osteodentin in shark teeth at multiple scales. We observed a complex 3D network of primary canals with a diameter ranging from ∼10 µm to ∼120 µm, where the canals are surrounded by osteon-like concentric layers of lamella, with 'interosteonal' tissue intervening between neighboring osteons. In addition, numerous hierarchically branched secondary canals extended out radially from the primary canals into the interosteonal tissue, with a decreasing diameter from ∼10 µm to hundreds of nanometers. Interestingly, the mineralization degree increases from the periphery of primary canals to the interosteonal tissue, suggesting that mineralization begins in the interosteonal tissue. Correspondingly, the hardness and elastic modulus of the interosteonal tissue is higher than those of the osteonal tissue. These results demonstrate that the 3D hierarchical canal network is positioned to play a critical role in controlling the gradient mineralization of osteodentin, also providing valuable insight into the formation of mineralized collagenous tissue without osteocytes and LCN. STATEMENT OF SIGNIFICANCE: : Bone is a composite material with versatile mechanical properties. Osteocytes and lacuno-canalicular network (LCN) are kown to play critical roles during formation of human bone. However, the skeleton of many fishes, including bone and osteodentin, although lacking osteocytes and LCN, could exhibit similar osteon-like structure and mechanical functions. Here, using various high resolution 3D characterization techniques, we reveal that the 3D network of primary canals and numerous hierarchically branched secondary canals correlate with the mineralization gradient and micromechanical properties of osteonal and interosteonal tissues of shark tooth osteodentin. This work significantly improves our understanding of the construction of bone-like mineralized tissue without osteocytes and LCN, and provides inspirations for the fabrication of functional materials with hierarchical structure.

Insights on the Formation Conditions of Manganese Oxides from Crimora, VA (USA)

Many regions of the United States contain manganese deposits economically valuable in New England, Appalachian, and Piedmont regions in the Eastern United States, in Northern Arkansas, and, to a small extent, in Central–Western California. Mn oxide/hydroxide (commonly referred to as Mn oxide minerals) are found in a wide variety of geological settings and occur as fine-grained aggregates, veins, marine and freshwater nodules and concretions, crusts, dendrites, and coatings on rock surfaces (e.g., desert varnish). How manganese oxides form and what mechanisms determine which oxides are likely to form are limited and still debated. This paper focuses on Mn oxides collected at the southern bound of the abandoned open-pit site called Crimora Mine (Augusta County, Virginia). This study uses mineralogical and chemical features to shed light on the origin of manganese deposits in Crimora along the western foot of the Blue Ridge in South–West Virginia. We report the first detailed study on the genesis of the Crimora manganese deposit conducted since the mine was closed in the 1950s. Crimora Mine sample is dark black fine- to medium-grained round and oblong nodules coated with a fine-grained intermix of yellowish earthy limonite, clays, and quartz. Scanning electron microscopy (SEM) revealed that the Crimora Mn-oxides exhibit concentric layering, breccia-like matrices, and veins. X-ray powder diffraction (XRPD) identified the set of Mn minerals as hollandite and birnessite. The concentration and range of dissolved chemical species in freshwater, seawater, and hydrothermal depositional fluids impart a geochemical signature to the Mn-oxides, providing a diagnostic tool to shed light on their genetic origin. Inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis of the Crimora manganese oxides shows Mn, Fe, and Ti, as well as trace elements such as Co, Ba, Y, Zn, Cr, Ni, Tl, La, V, and Li. A bivariate analysis based on the geochemical correlation of Mn and other common substituting cations (e.g., Fe, Co, Ti) shows a mixed genesis in different environments with varying biological and sedimentary supergene (freshwater and marine) conditions. These data suggest that the Mn-rich deposit in Crimora, VA, was formed in a continental margin environment of surficial deposits and reprecipitated in mixed biogenic and supergene conditions.

Intrinsic reaction selectivity between gaseous HCl and SO2 over ethanol-hydrated CaO adsorbent in coal-fired flue gas dechlorination

The reaction selectivity between HCl and SO2 on Ca-based adsorbents has attracted increasing concern for coal-fired flue gas HCl removal, while previous studies have not reached a convincing consensus. To address this knowledge gap, the reaction selectivity of HCl and SO2 over a newly-developed ethanol-hydrated CaO adsorbent was studied under series of experimental conditions. Essential factors of temperature, SO2 concentration, and products layers on the HCl reaction selectivity were revealed and the reaction pathways, thermodynamic and kinetic characteristics and turnover frequency were elucidated using DFT calculations. The results show that HCl has superior priority over SO2 to active sites. Though the opponent SO2 has thermodynamic advantage in terms of Gibbs free energy and adsorption ratios in equilibrium state, the reaction selectivity highly depends on the kinetics, where the dechlorination reaction shows larger chemical reaction rate than desulfurization reactions. The in-situ FTIR spectra indicates that HCl reacts with the desulfurized products, which exhibits the cleaning effect of sulfide product layers and benefits the high selectivity of the dechlorination reaction. The findings of competitive reaction mechanism of HCl and SO2 on Ca-based adsorbents provide a good foundation for flue gas dechlorination in commercial applications.

Loading-unloading of spherical and cylindrical cavities in cohesive-frictional materials with arbitrary radially symmetric boundary conditions

Many scenarios in geotechnical engineering involve cavity unloading from a loaded state under different boundary conditions, especially for thick-walled cylinder tests in laboratory conditions. A novel analytical cavity expansion-contraction solution is proposed for modeling thick-walled cylinder tests during a complete loading-unloading process under arbitrary symmetric boundary conditions. The proposed solution has potential implication in investigating ambiguous boundary effects for problems involving cavity expansion-contraction. The mechanical model considers two concentric layers of materials around the cavity, where the inner layer is considered as cohesive-frictional and the circumambient infinite layer is assumed as elastic to simulate the arbitrary radially symmetric boundary condition, including two extreme scenarios with constant-pressure and zero-displacement boundaries. The derived solution provides the evolutions of cavity pressure and distributions of stresses and displacements in both layers during the loading-unloading process, which is then rigorously validated against finite element results. The effects of boundary conditions and size of the cohesive-frictional layer have been comprehensively investigated by analyzing the cavity pressure and the developments of plastic zones during expansion and contraction. The developed solution has been proved to be applicable in geotechnical engineering, with comparisons between analytical results and experimental data for pressuremeter tests in calibration chambers and pile installation tests in a rigid container. The proposed solution might also be helpful in the analysis of autofrettaged pressure vessels.

Extended-bandwidth solar nano-concentrator integrated with graphene-metamaterial for photovoltaic energy harvesting applications

Concentration photovoltaics are used to achieve solar energy focusing on small-area solar cells, thus obtaining a high efficiency at a reasonable cost. An array of gold plasmonic concentrator cells is proposed here, which can nano-focus the solar radiation down to 60 nm spot size. It works over the entire solar energy bandwidth up to 2400 nm wavelength, which is extended beyond the conventional solar cells known maximum operating wavelength of 1800 nm. The concentrator consists of a coaxial waveguide with a tapered section that can plasmonically nano-focus solar radiation, followed by a straight waveguide section to propagate focused light along a graphene metamaterial for optical absorption. The metamaterial is integrated within the 60 nm gap of the straight waveguide section. The metamaterial consists of 10 concentric graphene shell layers, which are cross-connected by 5 horizontal graphene annuli. The concentrator and metamaterial design maximizes the solar optical absorption efficiency within the graphene metamaterial. The graphene optical absorption is enhanced up to 27 times with an almost flat response covering most of the solar bandwidth. The plasmonic absorption within the gold surfaces of the structure is found to be reasonable. The enhanced optical absorption of the weak solar radiation received within the extended band (1800–2400 nm) can reach up to 50%. The concentrator device is polarization insensitive with a 120o field-of-view. The enhanced optical power absorption in graphene metamaterial could be used in photovoltaic energy harvesting applications.

Practical Forecasting of AC Losses in Multi-Layer 2G-HTS Cold Dielectric Conductors

With the recent progresses on the designing and manufacturing of lightweight superconducting cables with high engineering current density, the need for a reliable, fast, and accurate computational model forecasting the alternating current (AC) losses of cold-dielectric conductors is pivotal for power grid investors and operators. However, validating such models is not an easy task. This is due to the low availability of experimental data for large scale power cables, and likewise, because of the large computational burden which underlies the total number of second generational high temperature superconducting (2G-HTS) tapes in the modelling of realistic power cables. Thus, aiming to overcome these challenges, we present a detailed two-dimensional H-model capable to reproduce the experimentally measured AC-losses of multi-layer power cables made of tens of 2G-HTS tapes. Two cable designs with very high critical currents ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{1.7}~kA$</tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{3.2}~kA$</tex-math></inline-formula> ) have been considered. These are composed of five and six concentric layers wound over a cylindrical former consisting of 50 and 67 2G-HTS tapes, respectively. In both situations a remarkable resemblance between the simulations and experiments has been found, offering a unique view of the local electrodynamics of the wound tapes where the mechanisms of shielding, magnetization, and transport currents coexist within the hysteretic process.

Identification of CgeA as a glycoprotein that anchors polysaccharides to the spore surface in Bacillus subtilis.

The Bacillus subtilis spore is composed of a core, containing chromosomal DNA, surrounded by a cortex layer made of peptidoglycan, and a coat composed of concentric proteinaceous layers. A polysaccharide layer is added to the spore surface, and likely anchored to the crust, the coat outermost layer. However, the identity of the coat protein(s) to which the spore polysaccharides (SPS) are attached is uncertain. First, we showed that the crust proteins CotVWXYZ and CgeA were all contained in the peeled SPS layer obtained from a strain missing CotE, the outer coat morphogenetic protein, suggesting that the SPS is indeed bound to at least one of the spore surface proteins. Second, CgeA is known to be located at the most downstream position in the crust assembly pathway. An analysis of truncated variants of CgeA suggested that its N-terminal half is required for localization to the spore surface, while its C-terminal half is necessary for SPS addition. Third, an amino acid substitution strategy revealed that SPS was anchored at threonine 112 (T112), which constitutes a probable O-glycosylation site on CgeA. Our results indicated that CgeA is a glycoprotein required to initiate SPS assembly and serves as an anchor protein linking the crust and SPS layers.

Effects of electron–phonon interactions on electrical transport properties of GaAs/GaAlAs semiconductor heterostructure

The effects of electron–phonon coupling, and band bending are studied in a quasi-one-dimensional (1D) heterostructure consisting of two different doping concentration layers attached between two ideal semi-infinite electrodes, theoretically. The layers are composed two types of material Ga1−c1Alc1As (with Al doping concentration c1) and Ga1−c2Alc2As (with Al doping concentration c2), which c1≤c2. We use the Green’s function method within the framework of the tight-binding approximation to calculate the electrical transport properties in the coherent regime. The transmission spectrum and also the electrical transport properties are investigated for incident electrons by varying the doping concentration and structural parameters. By modifying these parameters, we found the bandgaps, saddle-like behavior and resonance energies of the system in the transmission spectrum. This causes to allow or forbid the transmission of electrons in certain energy ranges. The numerical results can support the choice of suitable parameters to design and fabricate nano-energy filter devices for specific purposes.

The ATLAS RPC system for the LHC Run-3

Resistive Plate Chambers (RPCs) provide the barrel region of the ATLAS detector with an independent muon trigger and a two-coordinate measurement. The chambers, 3720 gas volumes in total covering a surface area of 3650 m2, are arranged in three concentric double layers and operated in a strong magnetic toroidal field.The system was originally designed to operate for 10 years with an instantaneous luminosity up to the LHC nominal value of 1034 cm−2 s−1. After a successful data taking period in Run-2, when the instantaneous luminosity more than doubled its design value, the detector has undergone an intense maintenance to ensure an efficient data taking during the just started Run-3.Several interventions have been carried out on the detector mainly concerning the gas distribution with the aim of stabilizing the system and reducing the amount of gas released into the atmosphere. The main interventions were: (a) new gas distribution racks have been added in order to increase the vertical segmentation and in view of the installation of the new chambers for the phase-2 upgrade, (b) non-return valves have been installed on the chamber outputs to avoid reverse flow with large leaks, (c) a massive repair campaign has been done for fixing the continuously developing leaks, (d) a new repair technique to fix and prevent new leaks has been tested and (e) the segmentation of the HV channels has been doubled in a third of the spectrometer to mitigate the effect of detector failures.The different aspects of the activity carried out in LS2 (Long Shutdown 2) are described, from motivation to implementation. The first measurements to assess the system performance are also presented.

An initial ecological characterization of mesopelagic fauna at Johnston Atoll and Musicians Seamounts

The mesopelagic region (200–1000 m) hosts a wide variety of organisms in a concentrated layer known as the deep scattering layer (DSL). Much of the mesopelagic region in the central North Pacific remains unexplored, limiting ecosystem considerations in fisheries management and other applications. The National Oceanic and Atmospheric Administration (NOAA) Office of Ocean Exploration and Research used NOAA Ship Okeanos Explorer to conduct two expeditions in the region, one to Johnston Atoll and the other to Musicians Seamounts. During these expeditions, a remotely operated vehicle collected video and CTD environmental data while the ship collected active acoustics. This project analyzed the video, CTD, and acoustic data to create an ecological characterization of the mesopelagic at Johnston Atoll and Musicians Seamounts. The initial characterization included a full inventory of mesopelagic fauna imaged, the relationship between the abundance of categorical groups (gelatinous, Chaetognatha, Crustacea, and fish) and the environmental variables of salinity, oxygen, and temperature, a comparison between the abundance of mesopelagic fauna below, within, and above the DSL, and a qualitative analysis of the spatial distribution of categorical groups. There was a significant negative relationship between the abundance of the gelatinous organisms and salinity and oxygen concentrations. Overall, there were more sightings per minute of all organisms combined below and within the DSL than above the DSL at Musicians Seamounts, while there was no difference in sightings per minute between the below, within, and above DSL groups at Johnston Atoll. Proportionally, there were more gelatinous organisms than any other single category (fish, Chaetognatha, and Crustacea) at all dive sites in the study. These initial characterizations strive to develop biodiversity concepts and the relationships between the environment and fauna. Progress in these areas can aid the management of marine national monuments and serve as a baseline for future ROV dives.

Steady Compressible Euler Equations of Concentration Layers for Hypersonic-limit Flows Passing Three-dimensional Bodies and Generalized Newton-Busemann Pressure Law

Steady Compressible Euler Equations of Concentration Layers for Hypersonic-limit Flows Passing Three-dimensional Bodies and Generalized Newton-Busemann Pressure Law

Three-dimensional bio-convection mechanism and heat transportation of nanofluid induced by magnetic field

There are several uses for bio-convection mechanisms, such as in sedimentary pools, fuel models, and microbially accelerated oil restoration. These are the basis of motile microorganisms which are applied to improve the mixability of fluid and tiny nanoparticles because they are accountable for biological transmission procedure. This work examines the bio-convective nanoparticles fluid flow and electrically conducting incompressible magneto-hydrodynamic flow of nanofluid towards a chemically reactive stretchable surface. Buongiorno model is considered here, which incorporates Brownian motion and thermophoretic diffusion, is employed in this study to explain how nanofluids improve heat transfer. The controlling boundary layer nonlinear PDEs are converted into ODEs by utilizing certain suitable similarity approaches. Numerical scheme is adopted to solve the transformed ordinary differential equations. The main findings of this research are that the magnetic field slows motion of the fluid when the thermal and mass buoyancy forces speed it up, and that thermophoretic diffusion increases the temperature and concentration of dimensionless fluids, resulting in stronger concentration and thermal boundary layers. The Brownian motion, concentration exponent, and chemical reaction parameters show an inverse relationship between temperature and concentration. Additionally, the first-order chemical reaction creates a lighter concentration boundary layer while the magnetic field’s presence due to impact of thermal and mass buoyancies helps to lower the heat transfer rate and shear stress. The findings show that while the Nusselt number and wall shear stress values are declining, the microorganism number is increasing.

The distribution function of mass density — A tool for the analysis of sphere particle systems

A method for characterizing sphere particle systems based on the calculation of the distri- bution of the average mass density in concentric spherical layers surrounding an arbitrary center has been developed. The effectiveness of the method has been tested on several variants of polydisperse system models obtained in two different ways and one system obtained by full-scale modeling. The distribution of the mass density for both methods of generating model systems allows you to choose the better option. For a system obtained by the field simulation method, a difference in properties is shown depending on the position of the observation center. This paper introduces the MaDiS program which implements the developed method.

Relationship between summer time near-surface ozone concentration and planetary boundary layer height in Beijing

The planetary boundary layer height (PBLH) is critical in affecting the concentration of air pollutants at surface. The relationship between PBLH and surface ozone concentration can be complicated but not entirely clear. In this study, by using observations and WRF-Chem simulations, we explore the relationship between the surface ozone and the PBLH in the summer daytime in Beijing, a major global ozone pollution hotspot. It is found that the surface ozone-PBLH relationship exhibits a three-stage evolution with ozone: first, increasing with PBLH, then keeping steady, and finally falling. The two turning points are around 1000 and 2000 m respectively. This process is likely controlled by the different contributions of chemical production and vertical mixing. Specifically, when PBLH is below ∼1000 m, as PBLH increases, chemical production increases owing to the light enhancement whereas the ozone contribution from vertical mixing remains weak due to the decreased ozone concentration gradient between the surface and the upper layer, resulting in a net gain of surface ozone concentration. When the PBL continues to rise, chemical production contributes less mainly due to the decrease of ozone precursors at the surface, whereas vertical mixing becomes more vigorous that further diluting surface ozone, resulting in a net loss of surface ozone concentration, especially when PBLH reaches above ∼2000 m. Our results contribute to understanding the variability of surface ozone in Beijing area and provide insights for local ozone air quality control.

Addition of silica in the adhesive primer layer of composite systems used to repair leak defects in metallic pipelines

Fibre reinforced polymer composites are often used to repair through-thickness corrosion damage in metal pipes. Usually, a primer adhesive layer is initially applied to the surface of the pipe and then the composite reinforcement is applied in concentric layers. This paper investigates the possibility of adding silica as a low-cost thixotropic thickener to a commercial epoxy resin to facilitate the application of the prime layer while maintaining the strength and effectiveness of the repair after curing. The study of the influence of the silica concentration on the rheological behaviour of the adhesive before fully cured was performed using a rheometer. A preliminary study about the influence of different fractions of silica on the rupture force of metal-composite hybrid bonded joints after full cure showed a good result with the concentration of 1% by weight of epoxy resin. Then, hydrostatic burst tests were carried out on specimens with through-thickness defects, repaired using the same composite, but with two different initial adhesive layers (same surface finish and layer thickness, but with silica and without silica). The study shows that introducing a low fraction of silica facilitates the application of the primer and does not significantly affect the strength of the repair.

On the effects of surface waviness upon catalytic steam reforming of methane in micro-structured reactors - a computational study

The effects of wavy channels upon steam methane reforming in catalytic micro-structured reactors, using Nickle as the catalyst, are investigated numerically. Laminar, three-dimensional models of reacting flows, with heterogeneous chemistry, are developed and applied to micro-structured reactors with different wave patterns on their internal walls. It is observed that introduction of surface waves on the walls of reactor, can significantly alter production and consumption of H2 and CH4. This is shown to be due to large fluctuations in convective mass and heat transfer, induced by the surface waviness. In particular, it is shown that separation and reattachment of concentration and thermal boundary layers and the subsequent modifications in Sherwood and Nusselt number can significantly affect the catalytic processes over the walls of reactor. A major local intensification of catalytic processes is observed where Sherwood and Nusselt number are maximised. Similarly, the catalytic process becomes highly inefficient in places with minimal Sherwood (and Nusselt) number. The analyses further reveal that a strategic discrete coating of wavy walls with the catalyst can substantially improve the performance of microstructure. For example, by coating only 25% of the surface area of wavy walls, CH4 conversion rate and selectivity per coated surface area increase by 459% and 308% compared to those of an equivalent fully coated straight channel. This implies the possibility of developing highly efficient and cost-effective catalytic micro-reactors for production of hydrogen from methane.

Mixed Ruddlesden–Popper and Dion–Jacobson Phase Perovskites for Stable and Efficient Blue Perovskite LEDs

AbstractProducing efficient blue and deep blue perovskite LEDs (PeLEDs) still represents a significant challenge in optoelectronics. Blue PeLEDs still have problems relating to color, luminance, and structural and electrical stability so new materials are needed to achieve better performance. Recent reports suggest using low n states (n = 1, 2, 3) to achieve blue electroluminescence in Ruddlesden–Popper (RP) perovskite films. However, there are fewer reports on the other quasi‐2D structure, Dion–Jacobson (DJ) perovksites, despite their highly desirable optical properties, due to the difficulty in achieving charge injection. To resolve this issue, herein, w e have mixed DJ phase precursors, propane‐1,3‐diammonium (PDA) bromide into RP phase perovskites and fabricated low‐dimensional PeLEDs. It is found that these specific precursors aid in suppressing both the low n (n = 1) and high n (n ≥ 4) quasi‐2D RP phases and is an effective strategy in blue‐shifting sky‐blue RP perovskites into the sub‐470 nm region. With optimization of the PDA concentration and device layers, it is achieved an external quantum efficiency of 1.5% at 469 nm and stable electroluminescence for the first deep blue PeLED to be reported using DJ perovskites.

Controlling the drying characteristics of suspensions via colloidal interactions: Particle-scale modeling

During drying of colloidal suspensions, evaporation of the suspending liquid drives the formation of concentrated particle layers beneath the receding free surface. The particle layers can lower the drying rate especially when the suspensions contain small nanoparticles. We investigate how such drying characteristics are affected by interactions between particles by use of Langevin dynamics simulations, for which we develop an analytical model to evaluate the decreasing drying rate from the permeation resistance of the formed particle layers. Considering aqueous suspensions where the particles interact through DLVO potentials, we show that there is an ionic strength where the drying rate is the most lowered and that the decrease in the drying rate is remarkably suppressed when the particles aggregate at sufficiently high ionic strength. This behavior reflects the structure of particle layers varied by the interactions. Our result provides an example how to control the drying characteristics by suspension composition.

A Novel Introgression Line Library Derived from a Wild Melon Gives Insights into the Genetics of Melon Domestication, Uncovering New Genetic Variability Useful for Breeding.

A collection of 30 melon introgression lines (ILs) was developed from the wild accession Ames 24297 (TRI) into 'Piel de Sapo' (PS) genetic background. Each IL carried an average of 1.4 introgressions from TRI, and the introgressions represented 91.4% of the TRI genome. Twenty-two ILs, representing 75% of the TRI genome, were evaluated in greenhouse (Algarrobo and Meliana) and field (Alcàsser) trials, mainly to study traits related to domestication syndrome such as fruit weight (FW) and flesh content (FFP), as well as other fruit quality traits as fruit shape (FS), flesh firmness (FF), soluble solid concentration (SSC), rind color and abscission layer. The IL collection showed an impressive variation in size-related traits, with FW ranging from 800 to 4100 g, reflecting the strong effect of the wild genome on these traits. Most of the ILs produced smaller fruits compared with PS; however, unexpectedly, the IL TRI05-2 produced bigger fruits, likely due to new epistatic interacions with the PS genetic background. In contrast, the genotypic effect for FS was smaller, and few QTLs with notable effects were detected. Interestingly, variability was also observed for FFP, FF and SSC, rind color and abscission layer formation. Genes in these introgressions are candidates for having been involved in melon domestication and diversification as well. These results confirm that the TRI IL collection is a very powerful tool for mapping traits of agronomic interest in melon, allowing the confirmation of previously reported QTLs and the identification of new ones to better understand the domestication process of this crop.

Superhydrophobic Rotation-Chip for Computer-Vision Identification of Drug-Resistant Bacteria.

The transport, distribution, and mixing of microfluidics often require additional instruments, such as pumps and valves, which are not feasible when operated in point-of-care (POC) settings. Here, we present a simple microfluidic pathogen detection system known as Rotation-Chip that transfers the reagents between wells by manually rotating two concentric layers without using external instruments. The Rotation-Chip is fabricated by a simple computer numerical control (CNC) machining process and is capable of carrying out 60 multiplexed reactions with a simple 30 or 60° rotation. Leveraging superhydrophobic coating, a high fluid transport efficiency of 92.78% is achieved without observable leaking. Integrated with an intracellular fluorescence assay, an on-chip detection limit of 1.8 × 106 CFU/mL is achieved for ampicillin-resistant Escherichia coli (E. coli), which is similar to our off-chip results. We also develop a computer vision method to automatically distinguish positive and negative samples on the chip, showing 100% accuracy. Our Rotation-Chip is simple, low-cost, high-throughput, and can display test results with a single chip image, making it ideal for various multiplexing POC applications in resource-limited settings.