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BACKGROUND: Chronic rhinosinusitis with nasal polyps (CRSwNP) is a prevalent chronic inflammatory condition affecting the nose and paranasal sinuses, posing a significant socio-economic impact with substantial challenges in management. Biologics targeting type 2 inflammation such as dupilumab, have emerged as promising options. This study addresses a critical knowledge gap by comprehensively evaluating the 3-year impact of sustained dupilumab therapy in CRSwNP. METHODS: A multicentric, retrospective collection of real-world data from five tertiary referral centers in Germany was conducted, enrolling 150 adult patients. The study investigated patient-reported outcomes, disease-specific indices and clinical measures, focusing on therapeutic response persistence, adverse events, and factors influencing treatment continuity. RESULTS: Results indicate significant improvements in clinical parameters from baseline (n = 150) with sustained effectiveness after 36 months (n = 138) as indicated in mean score ± standard deviation. Dupilumab treatment significantly improved overall disease-related impairment (VAS score: 7.5 ± 2.5 to 1.6 ± 1.3) and rhinosinusitis symptoms (SNOT-22: 59.4 ± 19.4 to 18.0 ± 15.0). Nasal Polyp Scores (NPS) decreased (5.3 ± 1.8 to 0.7 ± 1.1), and olfactory function improved (3.2 ± 2.5 to 8.4 ± 2.8), with three out of four patients achieving normosmia or hyposmia after 36 months. An "Excellent" treatment response according to EUFOREA23 criteria was observed in 76.5% of patients after 36 months. Sixteen patients discontinued Dupilumab, 12 permanently. Adverse events totaled 69 in 48 patients, commonly self-limiting. CONCLUSION: The study highlights the enduring effectiveness and lack of habituation to dupilumab after a sustained therapy of 3 years, providing valuable insights into its long-term therapeutic implications for CRSwNP patients.
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PURPOSE: Antibody therapy for chronic rhinosinusitis with nasal polyps (CRSwNP) has been established in Germany since 2019. With limited long-term data on biologic treatment for CRSwNP, we conducted a comprehensive evaluation of our 4-year data. This monocentric study aims to assess the real-world effects of this treatment on clinical course, quality of life, treatment adherence, biologic switching, dual therapy, and comorbidities. METHODS: We retrospectively analysed biologic therapy data in patients with severe chronic rhinosinusitis with nasal polyps. 191 patients with CRSwNP treated with Dupilumab, Mepolizumab, or Omalizumab were observed for up to 4 years in a real-life setting. RESULTS: We observed clear symptom improvements with few side effects. No loss of efficacy or tolerability was noted during the 4-year period. Patients reported high satisfaction compared to previous therapies, with overall improved quality of life. Revision surgery or oral steroid use during biologic therapy was rare. Some patients prolonged injection intervals or discontinued steroid nasal spray. Biologic switching occurred infrequently due to side effects or inadequate response and was generally well tolerated. Many patients reported additional positive effects such as asthma or allergy symptom improvement and reduced medication intake. CONCLUSION: In summary, this study confirms the potency and tolerability of biologics for CRSwNP treatment, with sustained efficacy over 4 years. Biologic switching is a viable option for inadequate response or intolerable side effects. Therapy positively impacts Th2 comorbidities, corticosteroid requirements, surgery need, and overall compliance remains high. CLINICAL TRIAL REGISTRATION: Project No.: 22-0802. Registry name: Biologika bei Patient*innen mit chronischer Sinusitis mit Nasenpolypen.
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The objective of this study was to assess, through simulation, conductivity variations in pulp and paper circuits when recycling waste water treatment plant (WWTP) effluent with a view to reducing fresh water use in a tissue mill. WWTP effluent was recycled in the process for different uses. A PS2000 digital model coupled with the PHREEQC chemical simulation engine was used to identify and quantify the main sources of conductivity: caustic soda, sodium bisulphite and acetate production through anaerobic microbial activity. Recycling WWTP effluent enables fresh water uptake to be reduced by 50% when used for pulp dilution or white water, by 81% when used in paper machine showers, and up to 96% for all uses combined. As fresh water use decreases, circuit closure increases along with, consequently, COD and conductivity. COD build-up can be controlled by best available techniques application. Recycling WWTP effluent has a strong impact on conductivity. However, the impact of high conductivity levels on additives performance is limited in the case of the mill studied. Acetate concentration could be controlled by better agitation of tanks or the introduction of air by pumps. Furthermore, limiting acetate production can reduce the need for caustic soda to control the pH.
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Residuos Industriales , Papel , Reciclaje , Eliminación de Residuos Líquidos , Eliminación de Residuos Líquidos/métodos , Reciclaje/métodos , Conductividad Eléctrica , Modelos Teóricos , Aguas Residuales/químicaRESUMEN
Discotic ionic liquid crystals (DILCs) consist of self-assembled superdiscs of cations and anions that spontaneously stack in linear columns with high one-dimensional ionic and electronic charge mobility, making them prominent model systems for functional soft matter. Compared to classical nonionic discotic liquid crystals, many liquid crystalline structures with a combination of electronic and ionic conductivity have been reported, which are of interest for separation membranes, artificial ion/proton conducting membranes, and optoelectronics. Unfortunately, a homogeneous alignment of the DILCs on the macroscale is often not achievable, which significantly limits the applicability of DILCs. Infiltration into nanoporous solid scaffolds can, in principle, overcome this drawback. However, due to the experimental challenges to scrutinize liquid crystalline order in extreme spatial confinement, little is known about the structures of DILCs in nanopores. Here, we present temperature-dependent high-resolution optical birefringence measurement and 3D reciprocal space mapping based on synchrotron X-ray scattering to investigate the thermotropic phase behavior of dopamine-based ionic liquid crystals confined in cylindrical channels of 180 nm diameter in macroscopic anodic aluminum oxide membranes. As a function of the membranes' hydrophilicity and thus the molecular anchoring to the pore walls (edge-on or face-on) and the variation of the hydrophilic-hydrophobic balance between the aromatic cores and the alkyl side chain motifs of the superdiscs by tailored chemical synthesis, we find a particularly rich phase behavior, which is not present in the bulk state. It is governed by a complex interplay of liquid crystalline elastic energies (bending and splay deformations), polar interactions, and pure geometric confinement and includes textural transitions between radial and axial alignment of the columns with respect to the long nanochannel axis. Furthermore, confinement-induced continuous order formation is observed in contrast to discontinuous first-order phase transitions, which can be quantitatively described by Landau-de Gennes free energy models for liquid crystalline order transitions in confinement. Our observations suggest that the infiltration of DILCs into nanoporous solids allows tailoring their nanoscale texture and ion channel formation and thus their electrical and optical functionalities over an even wider range than in the bulk state in a homogeneous manner on the centimeter scale as controlled by the monolithic nanoporous scaffolds.
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BACKGROUND: Allergic rhinits is a prevalent condition, affecting a substantial proportion of the population. This study investigates the impact of ongoing biologic therapy, specifically with Dupilumab, on allergy diagnostics in patients with allergic rhinits. METHODS: Various tests, including the Skin Prick Test, serum IgE levels and Allergy Screening Panels, were examined for their effectiveness in detecting sensitizations during biologic treatment. RESULTS: The results indicate a significant decline in total IgE levels following biologic therapy initiation, aligning with previous findings on Dupilumab's inhibitory effects on IL-4 and IL-13. However, the specific IgE to total IgE ratio for major allergens was not significantly reduced. Comparing diagnostic tools, the Skin Prick Test demonstrates an impressive retention rate of sensitizations (98%) during Dupilumab treatment, outperforming the Allergy Screening Panel, which shows a 75% detection rate. Notably, the panel displays limitations in capturing lower sensitization levels. CONCLUSION: In summary, this study underscores that, despite the influence of biologic therapy on certain markers, standard allergy tests remain viable while emphasizing the importance of considering specific IgE levels rather than relying solely on CAP classes. The Skin Prick Test in particular proves to be a reliable tool for identifying sensitizations during Dupilumab treatment. The results offer valuable guidance for the diagnostic management of Allergic rhinits in individuals subjected to Dupilumab treatment.
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Anticuerpos Monoclonales Humanizados , Inmunoglobulina E , Rinitis Alérgica , Pruebas Cutáneas , Humanos , Anticuerpos Monoclonales Humanizados/uso terapéutico , Inmunoglobulina E/sangre , Inmunoglobulina E/inmunología , Masculino , Femenino , Adulto , Rinitis Alérgica/tratamiento farmacológico , Rinitis Alérgica/diagnóstico , Pruebas Cutáneas/métodos , Persona de Mediana Edad , AncianoRESUMEN
INTRODUCTION: Aspergillus fumigatus is the most common airborne allergen of the Aspergillus family. However, allergies to Aspergillus spp. are increasing, and subsequently, allergies to Aspergillus species other than fumigatus are also on the rise. Commercial diagnostic tools are still limited to Aspergillus fumigatus. Hence, there is a need for improved tests. We decided to investigate the correlation between serological sensitization to A. fumigatus and other Aspergillus species. METHODS: Hundred and seven patients with positive skin prick tests to A. fumigatus were included in this study. Immunoglobulin E (IgE) concentrations against A. fumigatus, A. terreus, A. niger, A. flavus, and A. versicolor were measured from specimens by fluorescent enzyme-linked immunoassays. RESULTS: Patients showed considerably higher IgE concentrations against A. fumigatus (6.00 ± 15.05 kUA/L) than A. versicolor (0.30 ± 1.01 kUA/L), A. niger (0.62 ± 1.59 kUA/L), A. terreus (0.45 ± 1.12 kUA/L), or A. flavus (0.41 ± 0.97 kUA/L). Regression analysis yielded weak positive correlations for all Aspergillus spp., but low r2 values and heteroscedastic distribution indicate an overall poor fit of the calculated models. CONCLUSION: Serological sensitization against A. fumigatus does not correlate with sensitization against other Aspergillus spp. To detect sensitization against these, other diagnostic tools like a skin prick test solution of different Aspergillus spp. are needed.
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Anticuerpos Antifúngicos , Aspergillus fumigatus , Aspergillus , Reacciones Cruzadas , Inmunoglobulina E , Pruebas Cutáneas , Humanos , Inmunoglobulina E/sangre , Inmunoglobulina E/inmunología , Reacciones Cruzadas/inmunología , Aspergillus fumigatus/inmunología , Masculino , Femenino , Aspergillus/inmunología , Adulto , Persona de Mediana Edad , Anticuerpos Antifúngicos/sangre , Anticuerpos Antifúngicos/inmunología , Anciano , Alérgenos/inmunología , Antígenos Fúngicos/inmunología , Adolescente , Adulto Joven , Aspergilosis/diagnóstico , Aspergilosis/inmunologíaRESUMEN
Polymers are known to wet nanopores with high surface energy through an atomically thin precursor film followed by slower capillary filling. We present here light interference spectroscopy using a mesoporous membrane-based chip that allows us to observe the dynamics of these phenomena in situ down to the sub-nanometer scale at milli- to microsecond temporal resolution. The device consists of a mesoporous silicon film (average pore size 6 nm) with an integrated photonic crystal, which permits to simultaneously measure the phase shift of thin film interference and the resonance of the photonic crystal upon imbibition. For a styrene dimer, we find a flat fluid front without a precursor film, while the pentamer forms an expanding molecular thin film moving in front of the menisci of the capillary filling. These different behaviors are attributed to a significantly faster pore-surface diffusion compared to the imbibition dynamics for the pentamer and vice versa for the dimer. In addition, both oligomers exhibit anomalously slow imbibition dynamics, which could be explained by apparent viscosities of six and eleven times the bulk value, respectively. However, a more consistent description of the dynamics is achieved by a constriction model that emphasizes the increasing importance of local undulations in the pore radius with the molecular size and includes a sub-nanometer hydrodynamic dead, immobile zone at the pore wall but otherwise uses bulk fluid parameters. Overall, our study illustrates that interferometric, opto-fluidic experiments with mesoporous media allow for a remarkably detailed exploration of the nano-rheology of polymeric liquids.
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PURPOSE: Newborns who fail the transient evoked otoacoustic emissions (TEOAE) but pass the automatic auditory brainstem response (AABR) in universal newborn hearing screening (UNHS), frequently have no further diagnostic test or follow-up. The present study aimed to investigate whether hearing loss might be missed by ignoring neonatal TEOAE failure in the presence of normal AABR. METHODS: A retrospective analysis was conducted in newborns presenting between 2017 and 2021 to a tertiary referral centre due to failure in the initial UNHS. The main focus was on infants who failed TEOAE tests, but passed AABR screening. The clinical characteristics and audiometric outcomes were analysed and compared with those of other neonates. RESULTS: Among 1,095 referred newborns, 253 (23%) failed TEOAE despite passing AABR screening. Of the 253 affected infants, 154 returned for follow-up. At 1-year follow-up, 46 (28%) achieved normal audiometric results. 32 (21%) infants had permanent hearing loss (HL) confirmed by diagnostic ABR, 58 (38%) infants had HL solely due to middle ear effusion (MEE), and for 18 (12%) infants HL was suspected without further differentiation. The majority of permanent HL was mild (78% mild vs. 13% moderate vs. 9% profound). The rate of spontaneous MEE clearance was rather low (29%) leading to early surgical intervention in 36 children. The profile of the risk factors for hearing impairment was similar to that of newborns with failure in both, TEOAE and AABR; however, there was a stronger association between the presence of risk factors and the incidence of HL (relative risk 1.55 vs. 1.06; odds ratio 3.61 vs. 1.80). CONCLUSION: In newborns, the discordance between a "refer" in TEOAE and a "pass" in AABR screening is associated with a substantial prevalence of hearing impairment at follow-up, especially in the presence of risk factors.
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Sordera , Pérdida Auditiva , Lactante , Niño , Humanos , Recién Nacido , Estudios Retrospectivos , Potenciales Evocados Auditivos del Tronco Encefálico/fisiología , Emisiones Otoacústicas Espontáneas , Pruebas Auditivas/métodos , Tamizaje Neonatal/métodos , Pérdida Auditiva/diagnóstico , Pérdida Auditiva/epidemiologíaRESUMEN
Linking structure to mechanical and elastic properties is a major concern for the development of novel electroactive materials. This work reports on the potential-induced changes in thickness and Young modulus of a substrate supported, perchlorate doped polypyrrole thin film (<100 nm) investigated with electrochemical atomic force microscopy (AFM) under in situ conditions. This was accomplished by nanomechanical mapping of potentiodynamically electropolymerized polypyrrole film in electrolyte solution with AFM during redox cycling. The polypyrrole film thickness and Young modulus follow the electrical potential nearly linearly, increasing due to solvent and ion influx as the film is oxidized, and decreasing during reduction. Our measurements also confirm the presence of a potential-independent, passive swelling which is accompanied by softening of the film, likely caused by osmotic effects. Additionally, the heterogeneous distribution of the Young modulus can be directly traced to the typical nodular surface topography of polypyrrole, with the top of the nodular area possessing lower modulus, thus highlighting the complex relationship between topography and elastic properties.
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Amphiphilic amino acids represent promising scaffolds for biologically active soft matter. In order to understand the bulk self-assembly of amphiphilic amino acids into thermotropic liquid crystalline phases and their biological properties a series of tyrosine ionic liquid crystals (ILCs) was synthesized, carrying a benzoate unit with 0-3 alkoxy chains at the tyrosine unit and a cationic guanidinium head group. Investigation of the mesomorphic properties by polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and X-ray diffraction (WAXS, SAXS) revealed smectic A bilayers (SmAd) for ILCs with 4-alkoxy- and 3,4-dialkoxybenzoates, whereas ILCs with 3,4,5-trisalkoxybenzoates showed hexagonal columnar mesophases (Colh), while different counterions had only a minor influence. Dielectric measurements revealed a slightly higher dipole moment of non-mesomorphic tyrosine-benzoates as compared to their mesomorphic counterparts. The absence of lipophilic side chains on the benzoate unit was important for the biological activity. Thus, non-mesomorphic tyrosine benzoates and crown ether benzoates devoid of additional side chains at the benzoate unit displayed the highest cytotoxicities (against L929 mouse fibroblast cell line) and antimicrobial activity (against Escherichia coli ΔTolC and Staphylococcus aureus) and promising selectivity ratio in favour of antimicrobial activity.
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Antiinfecciosos , Líquidos Iónicos , Cristales Líquidos , Animales , Ratones , Aminoácidos , Cristales Líquidos/química , Dispersión del Ángulo Pequeño , Difracción de Rayos X , Aminas , Tirosina , Benzoatos/químicaRESUMEN
The Internet of Food (IoF) is an emerging field in smart foodsheds, involving the creation of a knowledge graph (KG) about the environment, agriculture, food, diet, and health. However, the heterogeneity and size of the KG present challenges for downstream tasks, such as information retrieval and interactive exploration. To address those challenges, we propose an interactive knowledge and learning environment (IKLE) that integrates three programming and modeling languages to support multiple downstream tasks in the analysis pipeline. To make IKLE easier to use, we have developed algorithms to automate the generation of each language. In addition, we collaborated with domain experts to design and develop a dataflow visualization system, which embeds the automatic language generations into components and allows users to build their analysis pipeline by dragging and connecting components of interest. We have demonstrated the effectiveness of IKLE through three real-world case studies in smart foodsheds.
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Many biological materials exhibit a multiscale porosity with small, mostly nanoscale pores as well as large, macroscopic capillaries to simultaneously achieve optimized mass transport capabilities and lightweight structures with large inner surfaces. Realizing such a hierarchical porosity in artificial materials necessitates often sophisticated and expensive top-down processing that limits scalability. Here, an approach that combines self-organized porosity based on metal-assisted chemical etching (MACE) with photolithographically induced macroporosity for the synthesis of single-crystalline silicon with a bimodal pore-size distribution is presented, i.e., hexagonally arranged cylindrical macropores with 1 µm diameter separated by walls that are traversed by pores 60 nm across. The MACE process is mainly guided by a metal-catalyzed reduction-oxidation reaction, where silver nanoparticles (AgNPs) serve as the catalyst. In this process, the AgNPs act as self-propelled particles that are constantly removing silicon along their trajectories. High-resolution X-ray imaging and electron tomography reveal a resulting large open porosity and inner surface for potential applications in high-performance energy storage, harvesting and conversion or for on-chip sensorics and actuorics. Finally, the hierarchically porous silicon membranes can be transformed structure-conserving by thermal oxidation into hierarchically porous amorphous silica, a material that could be of particular interest for opto-fluidic and (bio-)photonic applications due to its multiscale artificial vascularization.
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BACKGROUND: Small-for-size syndrome (SFSS) is a major complication following extended liver resection. The role of platelets in the early development of SFSS remains to be cleared. We aimed to investigate the impact of platelets and PAR-4, a receptor for platelet activation, on the acute phase microcirculatory injury after liver resection by in vivo microscopy analyzing the changes in leukocyte recruitment, platelet-neutrophil interaction, and microthrombosis-induced perfusion failure. METHODS: Sixty-percent partial hepatectomy (PH) models using C57BL/6 mice receiving platelet depletion with anti-GPIbα, PAR-4 blockade with tcY-NH2, or vehicle treatment with saline were used. Sham-operated animals served as controls. Epifluorescence microscopic analysis was performed 2 h after PH to quantify the leukocyte recruitment and microcirculatory changes. Sinusoidal neutrophil recruitment, platelet-neutrophil interaction, and microthrombosis were evaluated using two-photon microscopy. ICAM-1 expression and liver liver injury were assessed in tissue/blood samples. RESULTS: The increments of leukocyte recruitment in post-sinusoidal venules and sinusoidal perfusion failure, the upregulation of ICAM-1 expression, and the deterioration of liver function 2 h after 60% PH were alleviated in the absence of platelets or by PAR-4 blockade. Intensified platelet-neutrophil interaction and microthrombosis in sinusoids were observed 2 h after 60% PH, which significantly attenuated after PAR-4 blockade. CONCLUSION: Platelets play a critical role in acute liver injury after extended liver resection within 2 h. The deactivation of platelets via PAR-4 blockade ameliorated liver function deterioration by suppressing early leukocyte recruitment, platelet-neutrophil interaction, and microthrombosis in hepatic sinusoids.
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Molécula 1 de Adhesión Intercelular , Daño por Reperfusión , Ratones , Animales , Hepatectomía , Microcirculación , Ratones Endogámicos C57BL , Hígado , Péptido HidrolasasRESUMEN
OBJECTIVE: Post-hepatectomy liver failure (PHLF) is the main limitation of extended liver resection. The molecular mechanism and the role of leukocytes in the development of PHLF remain to be unveiled. We aimed to address the impact of serine proteases (SPs) on the acute phase after liver resection by intravitally analyzing leukocyte recruitment and changes in hemodynamics and microcirculation of the liver. METHODS: C57BL/6 mice undergoing 60% partial hepatectomy were treated with aprotinin (broad-spectrum SP inhibitor), tranexamic acid (plasmin inhibitor), or vehicle. Sham-operated animals served as controls. In vivo fluorescence microscopy was used to quantify leukocyte-endothelial interactions immediately after, as well as 120 min after partial hepatectomy in postsinusoidal venules, along with measurement of sinusoidal perfusion rate and postsinusoidal shear rate. Recruitment of leukocytes, neutrophils, T cells, and parameters of liver injury were assessed in tissue/blood samples. RESULTS: Leukocyte recruitment, sinusoidal perfusion failure rate, and shear rate were significantly increased in mice after 60% partial hepatectomy compared to sham-operated animals. The inhibition of SPs or plasmin significantly attenuated leukocyte recruitment and improved the perfusion rate in the remnant liver. ICAM-1 expression and neutrophil recruitment significantly increased after 60% partial hepatectomy and were strongly reduced by plasmin inhibition. CONCLUSIONS: Endothelial activation and leukocyte recruitment in the liver in response to the increment of sinusoidal shear rate were hallmarks in the acute phase after liver resection. SPs mediated leukocyte recruitment and contributed to the impairment of sinusoidal perfusion in an ICAM-1-dependent manner in the acute phase after liver resection.
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Hepatectomía , Molécula 1 de Adhesión Intercelular , Ratones , Animales , Molécula 1 de Adhesión Intercelular/metabolismo , Serina Proteasas/metabolismo , Fibrinolisina/metabolismo , Ratones Endogámicos C57BL , Hígado/metabolismo , Leucocitos , MicrocirculaciónRESUMEN
The recent agreement to transfer nuclear submarine reactors and technology from two nuclear-weapon states to a non-nuclear-weapon state (AUKUS deal) highlights an unsolved problem in international safeguards: how to safeguard naval reactor fuel while it is on board an operational nuclear submarine. Proposals to extend existing safeguards technologies and practices are complicated by the need for civilian international inspectors to gain access to the interior of the submarine and the reactor compartment, which raises national security concerns. In this Letter we show that implementing safeguards on submarine propulsion reactors using a low-energy antineutrino reactor-off method, between submarine patrols, can by-pass the need for onboard access all together. We find that, using inverse beta decay, detectors can achieve a timely and high level of assurance that a submarine's nuclear core has not been diverted (detector mass of around 100 kg) nor its enrichment level changed (detector mass of around 10 tons).
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Any departure from graphene's flatness leads to the emergence of artificial gauge fields that act on the motion of the Dirac fermions through an associated pseudomagnetic field. Here, we demonstrate the tunability of strong gauge fields in nonlocal experiments using a large planar graphene sheet that conforms to the deformation of a piezoelectric layer by a surface acoustic wave. The acoustic wave induces a longitudinal and a giant synthetic Hall voltage in the absence of external magnetic fields. The superposition of a synthetic Hall potential and a conventional Hall voltage can annihilate the sample's transverse potential at large external magnetic fields. Surface acoustic waves thus provide a promising and facile avenue for the exploitation of gauge fields in large planar graphene systems.
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Ecosystem management and governance of cross-scale dependent systems require integrating knowledge about ecological connectivity in its multiple forms and scales. Although scientists, managers, and policymakers are increasingly recognizing the importance of connectivity, governmental organizations may not be currently equipped to manage ecosystems with strong cross-boundary dependencies. Managing the different aspects of connectivity requires building social connectivity to increase the flow of information, as well as the capacity to coordinate planning, funding, and actions among both formal and informal governance bodies. We use estuaries in particular the San Francisco Estuary, in California, in the United States, as examples of cross-scale dependent systems affected by many intertwined aspects of connectivity. We describe the different types of estuarine connectivity observed in both natural and human-affected states and discuss the human dimensions of restoring beneficial physical and ecological processes. Finally, we provide recommendations for policy, practice, and research on how to restore functional connectivity to estuaries.
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The lattice dynamics of preferentially aligned nanocrystals formed upon drying of aqueous Ba(NO3)2 solutions in a mesoporous silica glass traversed by tubular pores of approximately 12 nm are explored by Raman scattering. To interpret the experiments on the confined nanocrystals polarized Raman spectra of bulk single crystals and X-ray diffraction experiments are also performed. Since a cubic symmetry is inherent to Ba(NO3)2, a special Raman scattering geometry was utilized to separate the phonon modes of Ag and Eg species. Combining group-theory analysis and ab initio lattice dynamics calculations a full interpretation of all Raman lines of the bulk single crystal is achieved. Apart from a small confinement-induced line broadening, the peak positions and normalized peak intensities of the Raman spectra of the nanoconfined and macroscopic crystals are identical. Interestingly, the Raman scattering experiment indicates the existence of comparatively large,â¼10-20 µm, single-crystalline regions of Ba(NO3)2 embedded in the porous host, near three orders of magnitude larger than the average size of single nanopores. This is contrast to the initial assumption of non-interconnected pores. It rather indicates an inter-pore propagation of the crystallization front, presumably via microporosity in the pore walls.
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Polarizability is a key factor when it comes to an accurate description of different ionic systems. The general importance of including polarizability into molecular dynamics simulations was shown in various recent studies for a wide range of materials, ranging from proteins to water to complex ionic liquids and for solid-liquid interfaces. While most previous studies focused on bulk properties or static structure factors, this study investigates in more detail the importance of polarizable surfaces on the dynamics of a confined ionic liquid in graphitic slit pores, as evident in modern electrochemical capacitors or in catalytic processes. A recently developed polarizable force field using Drude oscillators is modified in order to describe a particular room temperature ionic liquid accurately and in agreement with recently published experimental results. Using the modified parameters, various confinements are investigated and differences between non-polarizable and polarizable surfaces are discussed. Upon introduction of surface polarizability, changes in the dipole orientation and in the density distribution of the anions and cations at the interface are observed and are also accompanied with a dramatic increase in the molecular diffusivity in the contact layer. Our results thus clearly underline the importance of considering not only the polarizability of the ionic liquid but also that of the surface.