ContiFormer: Continuous-Time Transformer for Irregular Time Series Modeling

Modeling continuous-time dynamics on irregular time series is critical to account for data evolution and correlations that occur continuously. Traditional methods including recurrent neural networks or Transformer models leverage inductive bias via powerful neural architectures to capture complex patterns. However, due to their discrete characteristic, they have limitations in generalizing to continuous-time data paradigms. Though neural ordinary differential equations (Neural ODEs) and their variants have shown promising results in dealing with irregular time series, they often fail to capture the intricate correlations within these sequences. It is challenging yet demanding to concurrently model the relationship between input data points and capture the dynamic changes of the continuous-time system. To tackle this problem, we propose ContiFormer that extends the relation modeling of vanilla Transformer to the continuous-time domain, which explicitly incorporates the modeling abilities of continuous dynamics of Neural ODEs with the attention mechanism of Transformers. We mathematically characterize the expressive power of ContiFormer and illustrate that, by curated designs of function hypothesis, many Transformer variants specialized in irregular time series modeling can be covered as a special case of ContiFormer. A wide range of experiments on both synthetic and real-world datasets have illustrated the superior modeling capacities and prediction performance of ContiFormer on irregular time series data. The project link is https://seqml.github.io/contiformer/.Comment: Neurips 2023 Poste

Identification of Proteins Interacting with Cytoplasmic High-Mobility Group Box 1 during the Hepatocellular Response to Ischemia Reperfusion Injury

Ischemia/reperfusion injury (IRI) occurs inevitably in liver transplantations and frequently during major resections, and can lead to liver dysfunction as well as systemic disorders. High-mobility group box 1 (HMGB1) plays a pathogenic role in hepatic IRI. In the normal liver, HMGB1 is located in the nucleus of hepatocytes; after ischemia reperfusion, it translocates to the cytoplasm and it is further released to the extracellular space. Unlike the well-explored functions of nuclear and extracellular HMGB1, the role of cytoplasmic HMGB1 in hepatic IRI remains elusive. We hypothesized that cytoplasmic HMGB1 interacts with binding proteins involved in the hepatocellular response to IRI. In this study, binding proteins of cytoplasmic HMGB1 during hepatic IRI were identified. Liver tissues from rats with warm ischemia reperfusion (WI/R) injury and from normal rats were subjected to cytoplasmic protein extraction. Co-immunoprecipitation using these protein extracts was performed to enrich HMGB1-protein complexes. To separate and identify the immunoprecipitated proteins in eluates, 2-dimensional electrophoresis and subsequent mass spectrometry detection were performed. Two of the identified proteins were verified using Western blotting: betaine–homocysteine S-methyltransferase 1 (BHMT) and cystathionine γ-lyase (CTH). Therefore, our results revealed the binding of HMGB1 to BHMT and CTH in cytoplasm during hepatic WI/R. This finding may help to better understand the cellular response to IRI in the liver and to identify novel molecular targets for reducing ischemic injury

Acoustic metamaterial absorbers based on multilayered sonic crystals

Through the use of a layered arrangement, it is shown that lossy sonic crystals can be arranged to create a structure with extreme acoustic properties, namely, an acoustic metamaterial. This artificial structure shows different effective fluids and absorptive properties in different orientations. Theoretical, numerical, and experimental results examining thermoviscous losses in sonic crystals are presented, enabling the fabrication and characterization of an acoustic metamaterial absorber with complex-valued anisotropic inertia. To accurately describe and fabricate such an acoustic metamaterial in a realizable experimental configuration, confining structures are needed which modify the effective properties, due to the thermal and viscous boundary layer effects within the sonic crystal lattice. Theoretical formulations are presented which describe the effects of these confined sonic crystals, both individually and as part of an acoustic metamaterial structure. Experimental demonstrations are also reported using an acoustic impedance tube. The formulations developed can be written with no unknown or empirical coefficients, due to the structured lattice of the sonic crystals and organized layering scheme; and it is shown that higher filling fraction arrangements can be used to provide a large enhancement in the loss factor. (C) 2015 AIP Publishing LLC.This work was supported by the U.S. Office of Naval Research (Award No. N000141210216) and by the Spanish Ministerio de Economia y Competitividad (MINECO) under Contract No. TEC2010-19751.Guild, M.; García Chocano, VM.; Kan, W.; Sánchez-Dehesa Moreno-Cid, J. (2015). Acoustic metamaterial absorbers based on multilayered sonic crystals. Journal of Applied Physics. 117(11):114902-1-114902-14. https://doi.org/10.1063/1.4915346S114902-1114902-1411711Dowling, J. P. (1992). Sonic band structure in fluids with periodic density variations. The Journal of the Acoustical Society of America, 91(5), 2539-2543. doi:10.1121/1.402990Sigalas, M. M., & Economou, E. N. (1992). Elastic and acoustic wave band structure. Journal of Sound and Vibration, 158(2), 377-382. doi:10.1016/0022-460x(92)90059-7Sánchez-Pérez, J. V., Caballero, D., Mártinez-Sala, R., Rubio, C., Sánchez-Dehesa, J., Meseguer, F., … Gálvez, F. (1998). Sound Attenuation by a Two-Dimensional Array of Rigid Cylinders. Physical Review Letters, 80(24), 5325-5328. doi:10.1103/physrevlett.80.5325Kock, W. E., & Harvey, F. K. (1949). Refracting Sound Waves. The Journal of the Acoustical Society of America, 21(5), 471-481. doi:10.1121/1.1906536Cervera, F., Sanchis, L., Sánchez-Pérez, J. V., Martínez-Sala, R., Rubio, C., Meseguer, F., … Sánchez-Dehesa, J. (2001). Refractive Acoustic Devices for Airborne Sound. Physical Review Letters, 88(2). doi:10.1103/physrevlett.88.023902Torrent, D., Håkansson, A., Cervera, F., & Sánchez-Dehesa, J. (2006). Homogenization of Two-Dimensional Clusters of Rigid Rods in Air. Physical Review Letters, 96(20). doi:10.1103/physrevlett.96.204302Torrent, D., & Sánchez-Dehesa, J. (2008). Anisotropic mass density by two-dimensional acoustic metamaterials. New Journal of Physics, 10(2), 023004. doi:10.1088/1367-2630/10/2/023004Cummer, S. A., Popa, B.-I., Schurig, D., Smith, D. R., Pendry, J., Rahm, M., & Starr, A. (2008). Scattering Theory Derivation of a 3D Acoustic Cloaking Shell. Physical Review Letters, 100(2). doi:10.1103/physrevlett.100.024301Torrent, D., & Sánchez-Dehesa, J. (2008). Acoustic cloaking in two dimensions: a feasible approach. New Journal of Physics, 10(6), 063015. doi:10.1088/1367-2630/10/6/063015Li, J., Fok, L., Yin, X., Bartal, G., & Zhang, X. (2009). Experimental demonstration of an acoustic magnifying hyperlens. Nature Materials, 8(12), 931-934. doi:10.1038/nmat2561Pendry, J. B., & Li, J. (2008). An acoustic metafluid: realizing a broadband acoustic cloak. New Journal of Physics, 10(11), 115032. doi:10.1088/1367-2630/10/11/115032Popa, B.-I., & Cummer, S. A. (2009). Design and characterization of broadband acoustic composite metamaterials. Physical Review B, 80(17). doi:10.1103/physrevb.80.174303Torrent, D., & Sánchez-Dehesa, J. (2010). Anisotropic Mass Density by Radially Periodic Fluid Structures. Physical Review Letters, 105(17). doi:10.1103/physrevlett.105.174301Gumen, L. N., Arriaga, J., & Krokhin, A. A. (2011). Metafluid with anisotropic dynamic mass. Low Temperature Physics, 37(11), 975-978. doi:10.1063/1.3672821Zigoneanu, L., Popa, B.-I., Starr, A. F., & Cummer, S. A. (2011). Design and measurements of a broadband two-dimensional acoustic metamaterial with anisotropic effective mass density. Journal of Applied Physics, 109(5), 054906. doi:10.1063/1.3552990Reyes-Ayona, E., Torrent, D., & Sánchez-Dehesa, J. (2012). Homogenization theory for periodic distributions of elastic cylinders embedded in a viscous fluid. The Journal of the Acoustical Society of America, 132(4), 2896-2908. doi:10.1121/1.4744933Naify, C. J., Chang, C.-M., McKnight, G., & Nutt, S. (2010). Transmission loss and dynamic response of membrane-type locally resonant acoustic metamaterials. Journal of Applied Physics, 108(11), 114905. doi:10.1063/1.3514082Yang, Z., Dai, H. M., Chan, N. H., Ma, G. C., & Sheng, P. (2010). Acoustic metamaterial panels for sound attenuation in the 50–1000 Hz regime. Applied Physics Letters, 96(4), 041906. doi:10.1063/1.3299007Naify, C. J., Chang, C.-M., McKnight, G., Scheulen, F., & Nutt, S. (2011). Membrane-type metamaterials: Transmission loss of multi-celled arrays. Journal of Applied Physics, 109(10), 104902. doi:10.1063/1.3583656Hussein, M. I., & Frazier, M. J. (2013). Metadamping: An emergent phenomenon in dissipative metamaterials. Journal of Sound and Vibration, 332(20), 4767-4774. doi:10.1016/j.jsv.2013.04.041Zhang, Y., Wen, J., Zhao, H., Yu, D., Cai, L., & Wen, X. (2013). Sound insulation property of membrane-type acoustic metamaterials carrying different masses at adjacent cells. Journal of Applied Physics, 114(6), 063515. doi:10.1063/1.4818435Manimala, J. M., & Sun, C. T. (2014). Microstructural design studies for locally dissipative acoustic metamaterials. Journal of Applied Physics, 115(2), 023518. doi:10.1063/1.4861632Oudich, M., Zhou, X., & Badreddine Assouar, M. (2014). General analytical approach for sound transmission loss analysis through a thick metamaterial plate. Journal of Applied Physics, 116(19), 193509. doi:10.1063/1.4901997Christensen, J., Romero-García, V., Picó, R., Cebrecos, A., de Abajo, F. J. G., Mortensen, N. A., … Sánchez-Morcillo, V. J. (2014). Extraordinary absorption of sound in porous lamella-crystals. Scientific Reports, 4(1). doi:10.1038/srep04674Sánchez-Dehesa, J., Garcia-Chocano, V. M., Torrent, D., Cervera, F., Cabrera, S., & Simon, F. (2011). Noise control by sonic crystal barriers made of recycled materials. The Journal of the Acoustical Society of America, 129(3), 1173-1183. doi:10.1121/1.3531815García-Chocano, V. M., Cabrera, S., & Sánchez-Dehesa, J. (2012). Broadband sound absorption by lattices of microperforated cylindrical shells. Applied Physics Letters, 101(18), 184101. doi:10.1063/1.4764560Climente, A., Torrent, D., & Sánchez-Dehesa, J. (2012). Omnidirectional broadband acoustic absorber based on metamaterials. Applied Physics Letters, 100(14), 144103. doi:10.1063/1.3701611Allard, J., & Champoux, Y. (1992). New empirical equations for sound propagation in rigid frame fibrous materials. The Journal of the Acoustical Society of America, 91(6), 3346-3353. doi:10.1121/1.402824Johnson, D. L., Koplik, J., & Dashen, R. (1987). Theory of dynamic permeability and tortuosity in fluid-saturated porous media. Journal of Fluid Mechanics, 176(-1), 379. doi:10.1017/s0022112087000727Tarnow, V. (1996). Compressibility of air in fibrous materials. The Journal of the Acoustical Society of America, 99(5), 3010-3017. doi:10.1121/1.414790Peyrega, C., & Jeulin, D. (2013). Estimation of acoustic properties and of the representative volume element of random fibrous media. Journal of Applied Physics, 113(10), 104901. doi:10.1063/1.4794501Perrot, C., Chevillotte, F., & Panneton, R. (2008). Dynamic viscous permeability of an open-cell aluminum foam: Computations versus experiments. Journal of Applied Physics, 103(2), 024909. doi:10.1063/1.2829774Perrot, C., Chevillotte, F., & Panneton, R. (2008). Bottom-up approach for microstructure optimization of sound absorbing materials. The Journal of the Acoustical Society of America, 124(2), 940-948. doi:10.1121/1.2945115Perrot, C., Chevillotte, F., Tan Hoang, M., Bonnet, G., Bécot, F.-X., Gautron, L., & Duval, A. (2012). Microstructure, transport, and acoustic properties of open-cell foam samples: Experiments and three-dimensional numerical simulations. Journal of Applied Physics, 111(1), 014911. doi:10.1063/1.3673523Tarnow, V. (1996). Airflow resistivity of models of fibrous acoustic materials. The Journal of the Acoustical Society of America, 100(6), 3706-3713. doi:10.1121/1.417233Kuwabara, S. (1959). The Forces experienced by Randomly Distributed Parallel Circular Cylinders or Spheres in a Viscous Flow at Small Reynolds Numbers. Journal of the Physical Society of Japan, 14(4), 527-532. doi:10.1143/jpsj.14.527Tournat, V., Pagneux, V., Lafarge, D., & Jaouen, L. (2004). Multiple scattering of acoustic waves and porous absorbing media. Physical Review E, 70(2). doi:10.1103/physreve.70.026609Martin, P. A., Maurel, A., & Parnell, W. J. (2010). Estimating the dynamic effective mass density of random composites. The Journal of the Acoustical Society of America, 128(2), 571-577. doi:10.1121/1.3458849Attenborough, K. (1983). Acoustical characteristics of rigid fibrous absorbents and granular materials. The Journal of the Acoustical Society of America, 73(3), 785-799. doi:10.1121/1.389045Evans, J. M., & Attenborough, K. (2002). Sound propagation in concentrated emulsions: Comparison of coupled phase model and core-shell model. The Journal of the Acoustical Society of America, 112(5), 1911-1917. doi:10.1121/1.1510142Schoenberg, M., & Sen, P. N. (1983). Properties of a periodically stratified acoustic half‐space and its relation to a Biot fluid. The Journal of the Acoustical Society of America, 73(1), 61-67. doi:10.1121/1.388724Arnott, W. P., Bass, H. E., & Raspet, R. (1991). General formulation of thermoacoustics for stacks having arbitrarily shaped pore cross sections. The Journal of the Acoustical Society of America, 90(6), 3228-3237. doi:10.1121/1.401432Fokin, V., Ambati, M., Sun, C., & Zhang, X. (2007). Method for retrieving effective properties of locally resonant acoustic metamaterials. Physical Review B, 76(14). doi:10.1103/physrevb.76.144302Baccigalupi, A. (1999). ADC testing methods. Measurement, 26(3), 199-205. doi:10.1016/s0263-2241(99)00033-0Salissou, Y., & Panneton, R. (2010). Wideband characterization of the complex wave number and characteristic impedance of sound absorbers. The Journal of the Acoustical Society of America, 128(5), 2868-2876. doi:10.1121/1.3488307Song, B. H., & Bolton, J. S. (2000). A transfer-matrix approach for estimating the characteristic impedance and wave numbers of limp and rigid porous materials. The Journal of the Acoustical Society of America, 107(3), 1131-1152. doi:10.1121/1.428404Guild, M. D., Garcia-Chocano, V. M., Kan, W., & Sánchez-Dehesa, J. (2014). Enhanced inertia from lossy effective fluids using multi-scale sonic crystals. AIP Advances, 4(12), 124302. doi:10.1063/1.490188

Enhanced inertia from lossy effective fluids using multi-scale sonic crystals

n this work, a recent theoretically predicted phenomenon of enhanced permittivity with electromagnetic waves using lossy materials is investigated for the analogous case of mass density and acoustic waves, which represents inertial enhancement. Starting from fundamental relationships for the homogenized quasi-static effective density of a fluid host with fluid inclusions, theoretical expressions are developed for the conditions on the real and imaginary parts of the constitutive fluids to have inertial enhancement, which are verified with numerical simulations. Realizable structures are designed to demonstrate this phenomenon using multi-scale sonic crystals, which are fabricated using a 3D printer and tested in an acoustic impedance tube, yielding good agreement with the theoretical predictions and demonstrating enhanced inertia.This work was supported by the U.S. Office of Naval Research (Award N000141210216).Guild, M.; García Chocano, VM.; Kan, W.; Sánchez-Dehesa Moreno-Cid, J. (2014). Enhanced inertia from lossy effective fluids using multi-scale sonic crystals. AIP Advances. 4(12). https://doi.org/10.1063/1.4901880S412Dowling, J. P. (1992). Sonic band structure in fluids with periodic density variations. The Journal of the Acoustical Society of America, 91(5), 2539-2543. doi:10.1121/1.402990Sigalas, M. M., & Economou, E. N. (1992). Elastic and acoustic wave band structure. Journal of Sound and Vibration, 158(2), 377-382. doi:10.1016/0022-460x(92)90059-7Kushwaha, M. S., Halevi, P., Dobrzynski, L., & Djafari-Rouhani, B. (1993). Acoustic band structure of periodic elastic composites. Physical Review Letters, 71(13), 2022-2025. doi:10.1103/physrevlett.71.2022Sánchez-Pérez, J. V., Caballero, D., Mártinez-Sala, R., Rubio, C., Sánchez-Dehesa, J., Meseguer, F., … Gálvez, F. (1998). Sound Attenuation by a Two-Dimensional Array of Rigid Cylinders. Physical Review Letters, 80(24), 5325-5328. doi:10.1103/physrevlett.80.5325Krokhin, A. A., Arriaga, J., & Gumen, L. N. (2003). Speed of Sound in Periodic Elastic Composites. Physical Review Letters, 91(26). doi:10.1103/physrevlett.91.264302Torrent, D., Håkansson, A., Cervera, F., & Sánchez-Dehesa, J. (2006). Homogenization of Two-Dimensional Clusters of Rigid Rods in Air. Physical Review Letters, 96(20). doi:10.1103/physrevlett.96.204302Torrent, D., & Sánchez-Dehesa, J. (2008). Anisotropic mass density by two-dimensional acoustic metamaterials. New Journal of Physics, 10(2), 023004. doi:10.1088/1367-2630/10/2/023004Zigoneanu, L., Popa, B.-I., Starr, A. F., & Cummer, S. A. (2011). Design and measurements of a broadband two-dimensional acoustic metamaterial with anisotropic effective mass density. Journal of Applied Physics, 109(5), 054906. doi:10.1063/1.3552990Torrent, D., & Sánchez-Dehesa, J. (2008). Acoustic cloaking in two dimensions: a feasible approach. New Journal of Physics, 10(6), 063015. doi:10.1088/1367-2630/10/6/063015Sanchis, L., García-Chocano, V. M., Llopis-Pontiveros, R., Climente, A., Martínez-Pastor, J., Cervera, F., & Sánchez-Dehesa, J. (2013). Three-Dimensional Axisymmetric Cloak Based on the Cancellation of Acoustic Scattering from a Sphere. Physical Review Letters, 110(12). doi:10.1103/physrevlett.110.124301Guild, M. D., Alù, A., & Haberman, M. R. (2014). Cloaking of an acoustic sensor using scattering cancellation. Applied Physics Letters, 105(2), 023510. doi:10.1063/1.4890614García-Chocano, V. M., Cabrera, S., & Sánchez-Dehesa, J. (2012). Broadband sound absorption by lattices of microperforated cylindrical shells. Applied Physics Letters, 101(18), 184101. doi:10.1063/1.4764560Christensen, J., Romero-García, V., Picó, R., Cebrecos, A., de Abajo, F. J. G., Mortensen, N. A., … Sánchez-Morcillo, V. J. (2014). Extraordinary absorption of sound in porous lamella-crystals. Scientific Reports, 4(1). doi:10.1038/srep04674Frenzel, T., David Brehm, J., Bückmann, T., Schittny, R., Kadic, M., & Wegener, M. (2013). Three-dimensional labyrinthine acoustic metamaterials. Applied Physics Letters, 103(6), 061907. doi:10.1063/1.4817934Climente, A., Torrent, D., & Sánchez-Dehesa, J. (2012). Omnidirectional broadband acoustic absorber based on metamaterials. Applied Physics Letters, 100(14), 144103. doi:10.1063/1.3701611Naify, C. J., Chang, C.-M., McKnight, G., & Nutt, S. (2010). Transmission loss and dynamic response of membrane-type locally resonant acoustic metamaterials. Journal of Applied Physics, 108(11), 114905. doi:10.1063/1.3514082Yang, Z., Dai, H. M., Chan, N. H., Ma, G. C., & Sheng, P. (2010). Acoustic metamaterial panels for sound attenuation in the 50–1000 Hz regime. Applied Physics Letters, 96(4), 041906. doi:10.1063/1.3299007Hussein, M. I., & Frazier, M. J. (2013). Metadamping: An emergent phenomenon in dissipative metamaterials. Journal of Sound and Vibration, 332(20), 4767-4774. doi:10.1016/j.jsv.2013.04.041Reyes-Ayona, E., Torrent, D., & Sánchez-Dehesa, J. (2012). Homogenization theory for periodic distributions of elastic cylinders embedded in a viscous fluid. The Journal of the Acoustical Society of America, 132(4), 2896-2908. doi:10.1121/1.4744933Carbonell, J., Cervera, F., Sánchez-Dehesa, J., Arriaga, J., Gumen, L., & Krokhin, A. (2010). Homogenization of two-dimensional anisotropic dissipative photonic crystal. Applied Physics Letters, 97(23), 231122. doi:10.1063/1.3526381Carbonell, J., Sánchez-Dehesa, J., Arriaga, J., Gumen, L., & Krokhin, A. (2011). Electromagnetic absorption in anisotropic photonic crystal of alumina cylinders. Metamaterials, 5(2-3), 74-80. doi:10.1016/j.metmat.2011.03.001Godin, Y. A. (2013). Effective complex permittivity tensor of a periodic array of cylinders. Journal of Mathematical Physics, 54(5), 053505. doi:10.1063/1.4803490Torrent, D., Sánchez-Dehesa, J., & Cervera, F. (2007). Evidence of two-dimensional magic clusters in the scattering of sound. Physical Review B, 75(24). doi:10.1103/physrevb.75.241404Martin, P. A., Maurel, A., & Parnell, W. J. (2010). Estimating the dynamic effective mass density of random composites. The Journal of the Acoustical Society of America, 128(2), 571-577. doi:10.1121/1.3458849Erokhin, S. G., Lisyansky, A. A., Merzlikin, A. M., Vinogradov, A. P., & Granovsky, A. B. (2008). Photonic crystals built on contrast in attenuation. Physical Review B, 77(23). doi:10.1103/physrevb.77.233102Song, B. H., & Bolton, J. S. (2000). A transfer-matrix approach for estimating the characteristic impedance and wave numbers of limp and rigid porous materials. The Journal of the Acoustical Society of America, 107(3), 1131-1152. doi:10.1121/1.42840

Broadband Acoustic Cloaking within an Arbitrary Hard Cavity

This paper reports the design, fabrication, and experimental validation of a broadband acoustic cloak for the concealing of three-dimensional (3D) objects placed inside an open cavity with arbitrary surfaces. This 3D cavity cloak represents the acoustic analogue of a magician hat, giving the illusion that a cavity with an object is empty. Transformation acoustics is employed to design this cavity cloak, whose parameters represent an anisotropic acoustic metamaterial. A practical realization is made of 14 perforated layers fabricated by drilling subwavelength holes on 1-mm-thick Plexiglas plates. In both simulation and experimental results, concealing of the reference object by the device is shown for airborne sound with wavelengths between 10 cm and 17 cm.W. W. K. and V. M. G.-C. contributed equally to this work. W. W. K., B. L., and J. C. C. acknowledge support by the National Basic Research Program of China (973 Program) (Grants No. 2010CB327803 and No. 2012CB921504), National Natural Science Foundation of China (Grants No. 11174138, No. 11174139, No. 11222442, No. 81127901, and No. 11274168), NCET-12-0254, a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions and a program supported by China Scholarship Council (CSC). W. W. K. was also supported by the program for outstanding Ph.D. students of Nanjing University. V. M. G.-C, F. C., and J. S.-D. acknowledge financial support from the U.S. Office of Naval Research under Grant No. N00014-12-1-0216 and from the Spanish Ministerio de Economia y Competitividad under Grant No. TEC2010-19751.Kan, W.; Garcia Chocano, VM.; Cervera Moreno, FS.; Liang, B.; Zou, X.; Yin, L.; Cheng, J.... (2015). Broadband Acoustic Cloaking within an Arbitrary Hard Cavity. Physical Review Applied. 3(6):064019-1-064019-9. doi:10.1103/PhysRevApplied.3.064019S064019-1064019-93

Gaseous air pollution and emergency hospital visits for hypertension in Beijing, China: a time-stratified case-crossover study

Background: A number of epidemiological studies have been conducted to research the adverse effects of air pollution on mortality and morbidity. Hypertension is the most important risk factor for cardiovascular mortality. However, few previous studies have examined the relationship between gaseous air pollution and morbidity for hypertension. ---------- Methods: Daily data on emergency hospital visits (EHVs) for hypertension were collected from the Peking University Third Hospital. Daily data on gaseous air pollutants (sulfur dioxide (SO2) and nitrogen dioxide (NO2)) and particulate matter less than 10 μm in aerodynamic diameter (PM10) were collected from the Beijing Municipal Environmental Monitoring Center. A time-stratified case-crossover design was conducted to evaluate the relationship between urban gaseous air pollution and EHVs for hypertension. Temperature and relative humidity were controlled for. ---------- Results: In the single air pollutant models, a 10 μg/m3 increase in SO2 and NO2 were significantly associated with EHVs for hypertension. The odds ratios (ORs) were 1.037 (95% confidence interval (CI): 1.004-1.071) for SO2 at lag 0 day, and 1.101 (95% CI: 1.038-1.168) for NO2 at lag 3 day. After controlling for PM10, the ORs associated with SO2 and NO2 were 1.025 (95% CI: 0.987-1.065) and 1.114 (95% CI: 1.037-1.195), respectively.---------- Conclusion: Elevated urban gaseous air pollution was associated with increased EHVs for hypertension in Beijing, China

Membrane tension controls adhesion positioning at the leading edge of cells

Cell migration is dependent on adhesion dynamics and actin cytoskeleton remodeling at the leading edge. These events may be physically constrained by the plasma membrane. Here, we show that the mechanical signal produced by an increase in plasma membrane tension triggers the positioning of new rows of adhesions at the leading edge. During protrusion, as membrane tension increases, velocity slows, and the lamellipodium buckles upward in a myosin II-independent manner. The buckling occurs between the front of the lamellipodium, where nascent adhesions are positioned in rows, and the base of the lamellipodium, where a vinculin-dependent clutch couples actin to previously positioned adhesions. As membrane tension decreases, protrusion resumes and buckling disappears, until the next cycle. We propose that the mechanical signal of membrane tension exerts upstream control in mechanotransduction by periodically compressing and relaxing the lamellipodium, leading to the positioning of adhesions at the leading edge of cells

Arbuscular Mycorrhizal Fungi Selectively Promoted the Growth of Three Ecological Restoration Plants

Arbuscular mycorrhizal inoculation can promote plant growth, but specific research on the difference in the symbiosis effect of arbuscular mycorrhizal fungi and plant combination is not yet in-depth. Therefore, this study selected Medicago sativa L., Bromus inermis Leyss, and Festuca arundinacea Schreb., which were commonly used for restoring degraded land in China to inoculate with three AMF separately, to explore the effects of different AMF inoculation on the growth performance and nutrient absorption of different plants and to provide a scientific basis for the research and development of the combination of mycorrhiza and plants. We set up four treatments with inoculation Entrophospora etunicata (EE), Funneliformis mosseae (FM), Rhizophagus intraradices (RI), and non-inoculation. The main research findings are as follows: the three AMF formed a good symbiotic relationship with the three grassland plants, with RI and FM having more significant inoculation effects on plant height, biomass, and tiller number. Compared with C, the aboveground biomass of Medicago sativa L., Bromus inermis Leyss, and Festuca arundinacea Schreb. inoculated with AMF increased by 101.30–174.29%, 51.67–74.14%, and 110.67–174.67%. AMF inoculation enhanced the plant uptake of N, P, and K, and plant P and K contents were significantly correlated with plant biomass. PLS-PM analyses of three plants all showed that AMF inoculation increased plant nutrient uptake and then increased aboveground biomass and underground biomass by increasing plant height and root tillering. This study showed that RI was a more suitable AMF for combination with grassland degradation restoration grass species and proposed the potential mechanism of AMF–plant symbiosis to increase yield