bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of chamber wall loss of gaseous organic compounds on secondary organic aerosol formation: explicit modeling of SOA formation from alkane and alkene oxidation
Authors: La Y. S. , Camredon M. , Ziemann P. J. , Valorso R. , Matsunaga A. , Lannuque V. , Lee-Taylor J. , Hodzic A. , Madronich S. , Aumont B.
Published: September 2015

Abstract. Recent studies have shown that low volatility gas-phase species can be lost onto the smog chamber wall surfaces. Although this loss of organic vapors to walls could be substantial during experiments, its effect on secondary organic aerosol (SOA) formation has not been well characterized and quantified yet. Here the potential impact of chamber walls on the loss of gaseous organic species and SOA formation has been explored using the Generator for Explicit Chemistry and Kinetics of the Organics in the Atmosphere (GECKO-A) modeling tool which explicitly represents SOA formation and gas/wall partitioning. The model was compared with 41 smog chamber experiments of SOA formation under OH oxidation of alkane and alkene series (linear, cyclic and C12-branched alkanes and terminal, internal and 2-methyl alkenes with 7 to 17 carbon atoms) under high NOx conditions. Simulated trends match observed trends within and between homologous series. The loss of organic vapors to the chamber walls is found to affect SOA yields as well as the composition of the gas and the particle phases. Simulated distributions of the species in various phases suggest that nitrates, hydroxynitrates and carbonylesters could substantially be lost onto walls. The extent of this process depends on the rate of gas/wall mass transfer, the vapor pressure of the species and the duration of the experiments. This work suggests that SOA yields inferred from chamber experiments could be underestimated up to 0.35 yield unit due to the loss of organic vapors to chamber walls.
Tropical upper tropospheric humidity variations due to potential vorticity intrusions
Authors: Sandhya M. , Sridharan S. , Indira Devi M.
Published: September 2015

Abstract. Four cases (March 2009, May 2009, April 2010 and February 2012) are presented in which the ERA-interim relative humidity (RH) shows consistent increase by more than 50 % in the upper troposphere (200–250 hPa) over tropics at the eastward side of the potential vorticity (PV) intrusion region. The increase in RH is confirmed with the spaceborne microwave limb sounder observations and radiosonde observations over Gadanki (13.5° N, 79.2° E) and is observed irrespective of whether the PV intrusions are accompanied by deep convection or not. It is demonstrated that the increase in RH is due to poleward advection induced by the PV intrusions in their eastward side at the upper tropospheric heights. It is suggested that the low-latitude convection, which is not necessarily triggered by the PV intrusion, might have transported water vapour to the upper tropospheric heights.
Water limitations on forest carbon cycling and conifer traits along a steep climatic gradient in the Cascade Mountains, Oregon
Authors: Berner L. T. , Law B. E.
Published: September 2015

Abstract. Severe droughts occurred in the western United States during recent decades and continued human greenhouse gas emissions are expected to exacerbate warming and drying in this region. We investigated the role of water availability in shaping forest carbon cycling and morphological traits in the eastern Cascade Mountains, Oregon, focusing on the transition from low-elevation, dry western juniper (Juniperus occidentalis) woodlands to higher-elevation, wetter ponderosa pine (Pinus ponderosa) and grand fir (Abies grandis) forests. We examined 12 sites in mature forests that spanned a 1300 mm yr−1 gradient in mean growing-year climate moisture index (CMIgy ), computed annually (1964 to 2013) as monthly precipitation minus reference evapotranspiration and summed October to September. Maximum leaf area, annual aboveground productivity, and aboveground live tree biomass increased with CMIgy (r2 = 0.58–0.85, P < 0.05), approximately 50-, 30-, and 10-fold along this drier to wetter gradient. Interannual fluctuations in CMI affected the annual radial growth of 91 % of juniper, 51 % of pine, and 12 % of fir from 1964 to 2013. The magnitude of the site-average growth-CMI correlations decreased with increased CMIgy (r2 = 0.65, P < 0.05). All three species, particularly fir, experienced pronounced declines in radial growth from ca. 1985 to 1994, coinciding with a period of sustained below-average CMIgy and extensive insect outbreak. Traits of stress-tolerant juniper included short stature, high wood density for cavitation resistance, and high investment in water transport relative to leaf area. Species occupying wetter areas invested more resources in height growth in response to competition for light relative to investment in hydraulic architecture. Correspondingly, maximum tree height, leaf area:sapwood area ratio, and stem wood density were all correlated with CMIgy . The tight coupling of forest carbon cycling and species traits with water availability suggests that warmer and drier conditions projected for the 21st century could have significant biogeochemical, ecological, and social consequences in the Pacific Northwest.
Coupling global models for hydrology and nutrient loading to simulate nitrogen and phosphorus retention in surface water – description of IMAGE-GNM and analysis of performance
Authors: Beusen A. H. W. , Van Beek L. P. H. , Bouwman A. F. , Mogollón J. M. , Middelburg J. J.
Published: September 2015

Abstract. The IMAGE-Global Nutrient Model (GNM) is a global distributed spatially explicit model using hydrology as the basis for describing nitrogen (N) and phosphorus (P) delivery to surface water and transport and in-stream retention in rivers, lakes, wetlands and reservoirs. It is part of the integrated assessment model IMAGE, which studies the interaction between society and the environment over prolonged time periods. In the IMAGE-GNM model, grid cells receive water with dissolved and suspended N and P from upstream grid cells; inside grid cells, N and P are delivered to water bodies via diffuse sources (surface runoff, shallow and deep groundwater, riparian zones; litterfall in floodplains; atmospheric deposition) and point sources (wastewater); N and P retention in a water body is calculated on the basis of the residence time of the water and nutrient uptake velocity; subsequently, water and nutrients are transported to downstream grid cells. Differences between model results and observed concentrations for a range of global rivers are acceptable given the global scale of the uncalibrated model. Sensitivity analysis with data for the year 2000 showed that runoff is a major factor for N and P delivery, retention and river export. For both N and P, uptake velocity and all factors used to compute the subgrid in-stream retention are important for total in-stream retention and river export. Soil N budgets, wastewater and all factors determining litterfall in floodplains are important for N delivery to surface water. For P the factors that determine the P content of the soil (soil P content and bulk density) are important factors for delivery and river export.
On the relationships between Michaelis–Menten kinetics, reverse Michaelis–Menten kinetics, Equilibrium Chemistry Approximation kinetics and quadratic kinetics
Authors: Tang J. Y.
Published: September 2015

Abstract. The Michaelis–Menten kinetics and the reverse Michaelis–Menten kinetics are two popular mathematical formulations used in many land biogeochemical models to describe how microbes and plants would respond to changes in substrate abundance. However, the criteria of when to use which of the two are often ambiguous. Here I show that these two kinetics are special approximations to the Equilibrium Chemistry Approximation kinetics, which is the first order approximation to the quadratic kinetics that solves the equation of enzyme-substrate complex exactly for a single enzyme single substrate biogeochemical reaction with the law of mass action and the assumption of quasi-steady-state for the enzyme-substrate complex and that the product genesis from enzyme-substrate complex is much slower than the equilibration between enzyme-substrate complexes, substrates and enzymes. In particular, I showed that the derivation of the Michaelis–Menten kinetics does not consider the mass balance constraint of the substrate, and the reverse Michaelis–Menten kinetics does not consider the mass balance constraint of the enzyme, whereas both of these constraints are taken into account in the Equilibrium Chemistry Approximation kinetics. By benchmarking against predictions from the quadratic kinetics for a wide range of substrate and enzyme concentrations, the Michaelis–Menten kinetics was found to persistently under-predict the normalized sensitivity ∂ ln v / ∂ ln k2+ of the reaction velocity v with respect to the maximum product genesis rate k2+, persistently over-predict the normalized sensitivity ∂ ln v / ∂ ln k1+ of v with respect to the intrinsic substrate affinity k1+, persistently over-predict the normalized sensitivity ∂ ln v / ∂ ln [ E ]T of v with respect the total enzyme concentration [ E ]T and persistently under-predict the normalized sensitivity ∂ ln v / ∂ ln [ S ]T of v with respect to the total substrate concentration [ S ]T. Meanwhile, the reverse Michaelis–Menten kinetics persistently under-predicts ∂ ln v / ∂ ln k2+ and ∂ ln v / ∂ ln [ E ]T, and persistently over-predicts ∂ ln v / ∂ ln k1+ and ∂ ln v / ∂ ln [ S ]T. In contrast, the Equilibrium Chemistry Approximation kinetics always gives consistent predictions of ∂ ln v / ∂ ln k2+, ∂ ln v / ∂ ln k1+, ∂ ln v / ∂ ln [ E ]T and ∂ ln v / ∂ ln [ S ]T. Since the Equilibrium Chemistry Approximation kinetics includes the advantages from both the Michaelis–Menten kinetics and the reverse Michaelis–Menten kinetics and it is applicable for almost the whole range of substrate and enzyme abundances, soil biogeochemical modelers therefore no longer need to choose when to use the Michaelis–Menten kinetics or the reverse Michaelis–Menten kinetics. I expect removing this choice ambiguity will make it easier to formulate more robust and consistent land biogeochemical models.
Spatio-temporal variability of snow water equivalent in the extra-tropical Andes cordillera from a distributed energy balance modeling and remotely sensed snow cover
Authors: Cornwell E. , Molotch N. P. , McPhee J.
Published: September 2015

Abstract. Seasonal snow cover is the primary water resource precursor for human use and environmental sustain along the extratropical Andes Cordillera. Despite its importance, relatively little research has been devoted to understanding the properties, distribution and variability of this natural resource. This research provides high-resolution distributed estimates of end-of-winter and spring snow water equivalent over a 152 000 km2 domain that includes the mountainous reaches of central Chile and Argentina. Remotely sensed fractional snow covered area and other relevant forcings are combined with extrapolated data from meteorological stations and a simplified physically-based energy balance model in order to obtain melt-season peak SWE. Estimates show an overall coefficient of determination R2 of 0.61 compared to observations at 12 automatic snow water equivalent sensors distributed across the model domain, with R2 values between 0.32 and 0.88. Regional estimates of peak SWE accumulation show differential patterns strongly modulated by elevation, latitude and position relative to the continental divide. Average peak SWE increases by nearly 500 mm for every 1000 m in elevation gain for the central and southern sub-regions of the model domain, but this effect is much less pronounced in the northern reaches. The 3000–4000 m a.s.l. elevation band is the most significant accumulation area for most of the northern and central reaches of the domain, although the 4000–5000 m a.s.l. band, despite a smaller contributing area, almost doubles the accumulation amounts estimated for the lower adjacent subdomain. Snow accumulation reaches an earlier peak in the western Andes, and the eastern side of the continental divide shows lower snow accumulation at all elevations except for the southern region represented by the Neuquén River Basin. The results presented here have the potential of informing applications such as seasonal forecast model assessment and improvement, regional climate model validation, as well as evaluation of observational networks and water resource infrastructure development.
A TOPIC MODELING BASED REPRESENTATION TO DETECT TWEET LOCATIONS. EXAMPLE OF THE EVENT ”JE SUIS CHARLIE”
Authors: Morchid M. , Josselin D. , Portilla Y. , Dufour R. , Altman E. , Linarès G.
Published: September 2015

Abstract. Social Networks became a major actor in information propagation. Using the Twitter popular platform, mobile users post or relay messages from different locations. The tweet content, meaning and location, show how an event-such as the bursty one ”JeSuisCharlie”, happened in France in January 2015, is comprehended in different countries. This research aims at clustering the tweets according to the co-occurrence of their terms, including the country, and forecasting the probable country of a non-located tweet, knowing its content. First, we present the process of collecting a large quantity of data from the Twitter website. We finally have a set of 2,189 located tweets about “Charlie”, from the 7th to the 14th of January. We describe an original method adapted from the Author-Topic (AT) model based on the Latent Dirichlet Allocation (LDA) method. We define an homogeneous space containing both lexical content (words) and spatial information (country). During a training process on a part of the sample, we provide a set of clusters (topics) based on statistical relations between lexical and spatial terms. During a clustering task, we evaluate the method effectiveness on the rest of the sample that reaches up to 95% of good assignment. It shows that our model is pertinent to foresee tweet location after a learning process.
Amotl2a interacts with the Hippo effector Yap1 and the Wnt/β-catenin effector Lef1 to control tissue size in zebrafish
Authors: Agarwala Sobhika , Duquesne Sandra , Liu Kun , Boehm Anton , Grimm Lin , Link Sandra , König Sabine , Eimer Stefan , Ronneberger Olaf , Lecaudey Virginie
Published: September 2015

During development, proliferation must be tightly controlled for organs to reach their appropriate size. While the Hippo signaling pathway plays a major role in organ growth control, how it senses and responds to increased cell density is still unclear. In this study, we use the zebrafish lateral line primordium (LLP), a group of migrating epithelial cells that form sensory organs, to understand how tissue growth is controlled during organ formation. Loss of the cell junction-associated Motin protein Amotl2a leads to overproliferation and bigger LLP, affecting the final pattern of sensory organs. Amotl2a function in the LLP is mediated together by the Hippo pathway effector Yap1 and the Wnt/β-catenin effector Lef1. Our results implicate for the first time the Hippo pathway in size regulation in the LL system. We further provide evidence that the Hippo/Motin interaction is essential to limit tissue size during development.
Registered report: A coding-independent function of gene and pseudogene mRNAs regulates tumour biology
Authors: Khan Israr , Kerwin John , Owen Kate , Griner Erin ,   Reproducibility Project: Cancer Biology
Published: September 2015

The Reproducibility Project: Cancer Biology seeks to address growing concerns about reproducibility in scientific research by conducting replications of selected experiments from a number of high-profile papers in the field of cancer biology. The papers, which were published between 2010 and 2012, were selected on the basis of citations and Altmetric scores (Errington et al., 2014). This Registered report describes the proposed replication plan of key experiments from ‘A coding-independent function of gene and pseudogene mRNAs regulates tumour biology’ by Poliseno et al. (2010), published in Nature in 2010. The key experiments to be replicated are reported in Figures 1D, 2F-H, and 4A. In these experiments, Poliseno and colleagues report microRNAs miR-19b and miR-20a transcriptionally suppress both PTEN and PTENP1 in prostate cancer cells (Figure 1D; Poliseno et al., 2010). Decreased expression of PTEN and/or PTENP1 resulted in downregulated PTEN protein levels (Figure 2H), downregulation of both mRNAs (Figure 2G), and increased tumor cell proliferation (Figure 2F; Poliseno et al., 2010). Furthermore, overexpression of the PTEN 3′ UTR enhanced PTENP1 mRNA abundance limiting tumor cell proliferation, providing additional evidence for the co-regulation of PTEN and PTENP1 (Figure 4A; Poliseno et al., 2010). The Reproducibility Project: Cancer Biology is collaboration between the Center for Open Science and Science Exchange, and the results of the replications will be published in eLife.
Feeding state-dependent regulation of developmental plasticity via CaMKI and neuroendocrine signaling
Authors: Neal Scott J , Takeishi Asuka , O'Donnell Michael P , Park JiSoo , Hong Myeongjin , Butcher Rebecca A , Kim Kyuhyung , Sengupta Piali
Published: September 2015

Information about nutrient availability is assessed via largely unknown mechanisms to drive developmental decisions, including the choice of Caenorhabditis elegans larvae to enter into the reproductive cycle or the dauer stage. In this study, we show that CMK-1 CaMKI regulates the dauer decision as a function of feeding state. CMK-1 acts cell-autonomously in the ASI, and non cell-autonomously in the AWC, sensory neurons to regulate expression of the growth promoting daf-7 TGF-β and daf-28 insulin-like peptide (ILP) genes, respectively. Feeding state regulates dynamic subcellular localization of CMK-1, and CMK-1-dependent expression of anti-dauer ILP genes, in AWC. A food-regulated balance between anti-dauer ILP signals from AWC and pro-dauer signals regulates neuroendocrine signaling and dauer entry; disruption of this balance in cmk-1 mutants drives inappropriate dauer formation under well-fed conditions. These results identify mechanisms by which nutrient information is integrated in a small neuronal network to modulate neuroendocrine signaling and developmental plasticity.
Community-Based Participatory Research and System Dynamics Modeling for Improving Retention in Hypertension Care
Authors: Ye Jiancheng , Orji Ikechukwu A. , Birkett Michelle A. , Hirschhorn Lisa R. , Walunas Theresa L. , Smith Justin D. , Kandula Namratha R. , Shedul Gabriel L. , Huffman Mark D. , Ojji Dike B.
Published: August 2024

Importance

The high prevalence of hypertension calls for broad, multisector responses that foster prevention and care services, with the goal of leveraging high-quality treatment as a means of reducing hypertension incidence. Health care system improvements require stakeholder input from across the care continuum to identify gaps and inform interventions that improve hypertension care service, delivery, and retention; system dynamics modeling offers a participatory research approach through which stakeholders learn about system complexity and ways to model sustainable system-level improvements.

Objective

To assess the association of simulated interventions with hypertension care retention rates in the Nigerian primary health care system using system dynamics modeling.

Design, Setting, and Participants

This decision analytical model used a participatory research approach involving stakeholder workshops conducted in July and October 2022 to gather insights and inform the development of a system dynamics model designed to simulate the association of various interventions with retention in hypertension care. The study focused on the primary health care system in Nigeria, engaging stakeholders from various sectors involved in hypertension care, including patients, community health extension workers, nurses, pharmacists, researchers, administrators, policymakers, and physicians.

Exposure

Simulated intervention packages.

Main Outcomes and Measures

Retention rate in hypertension care at 12, 24, and 36 months, modeled to estimate the effectiveness of the interventions.

Results

A total of 16 stakeholders participated in the workshops (mean [SD] age, 46.5 [8.6] years; 9 [56.3%] male). Training of health care workers was estimated to be the most effective single implementation strategy for improving retention in hypertension care in Nigeria, with estimated retention rates of 29.7% (95% CI, 27.8%-31.2%) at 12 months and 27.1% (95% CI, 26.0%-28.3%) at 24 months. Integrated intervention packages were associated with the greatest improvements in hypertension care retention overall, with modeled retention rates of 72.4% (95% CI, 68.4%-76.4%), 68.1% (95% CI, 64.5%-71.7%), and 67.1% (95% CI, 64.5%-71.1%) at 12, 24, and 36 months, respectively.

Conclusions and Relevance

This decision analytical model study showed that community-based participatory research could be used to estimate the potential effectiveness of interventions for improving retention in hypertension care. Integrated intervention packages may be the most promising strategies.
In Situ Reconstruction Post‐Treatment for Efficient Carbon‐Based Hole‐Conductor‐Free Printable Mesoscopic Perovskite Solar Cells
Authors: Han Chuanzhou , Du Jiankang , Liu Zhiyang , Gao Qiaojiao , Chen Xiayan , Xiang Junwei , Xiao Xufeng , Cheng Yanjie , Chen Kai , Xia Minghao , Liu Jiale , Yang Li‐Ming , Zhou Yang , Mei Anyi , Han Hongwei
Published: August 2024

Perovskite solar cells are regarded as the most promising and disruptive photovoltaic of the new generation. Carbon‐based hole‐conductor‐free printable mesoscopic perovskite solar cells (p‐MPSCs) with three mesoscopic layers have garnered considerable interest owing to their simple manufacturing process and cost‐effective raw materials, signaling the potential for commercialization. However, the energy level mismatch between the perovskite and the carbon electrode as well as defects at perovskite grain boundaries inevitably lead to additional non‐radiative carrier recombination and large voltage loss. In this study, a facile in situ reconstruction post‐treatment approach is employed to integrate lead sulfide (PbS) and the two‐dimensional (2D) perovskite K2PbI4 into the mesoporous scaffolds of p‐MPSCs. In this way, grain boundary defects are effectively passivated and the ion migration is suppressed by introducing 2D perovskite K2PbI4 at grain boundaries. Besides, the incorporation of PbS leads to the downward shift of the Fermi level for perovskite, which enhances hole collection within the device by optimizing band alignment at the perovskite/carbon interface. Consequently, an improved efficiency exceeding 20% is achieved for p‐MPSCs with no significant performance degradation observed over a storage period of 235 days. This strategy provides a facile and novel approach toward fabricating highly efficient and stable p‐MPSCs.
Artificial Spider Silk Materials: From Molecular Design, Mesoscopic Assembly, to Macroscopic Performances
Authors: Shi Yu‐Xiao , Zhu Ya‐Jiao , Qian Zhi‐Gang , Xia Xiao‐Xia
Published: August 2024

Spider silk is one of the strongest and toughest fibrous materials available in nature. Its superior properties make it a good candidate for applications in various fields ranging from protective body armor to scaffolds for medical implants. However, harvesting a substantial amount of natural spider silk remains challenging because spiders cannot be easily bred. With the development of synthetic biology and its integration with materials science, considerable research has been directed toward engineering and production of synthetic spider silk materials. Here the study overviews general strategies on molecular design, mesoscopic assembly, and macroscopic regulation of artificial spider silk materials. The insights into the correlation between silk protein sequences, mesoscopic assemblies, and macroscopic material properties are provided for guiding de novo design and engineering of next‐generation spider silk materials. This review also emphasizes the challenges and future perspectives for advancing the translational research on these designer functional materials for diverse applications.
Shifting d‐band Center: An Overlooked Factor in Broadening Electromagnetic Wave Absorption Bandwidth
Authors: Yao Kai , Pan Fei , Liang Hongsheng , Zhang Xiang , Li Lixin , Song Lixin , Yang Yang , Yuan Bin , Lu Wei
Published: August 2024

Absorption bandwidth is one of the key performance metrics for electromagnetic wave (EMW) absorbers. Traditional oxide absorbers, despite their merits such as abundance, long‐term stability, and low cost, have long been plagued by their inferior absorption bandwidth (typically less than 4 GHz). Herein, a novel concept is proposed: the introduction of cation vacancies and heterostructures into oxides can remarkably broaden their absorption bandwidth. A broadening value of 7.75 GHz is observed through this route, surpassing the broadening achieved by other existing engineering methods, by ≈100%. Crucially, this study discovers that a negative shift in the d‐band center, a previously overlooked factor, is responsible for this broadening phenomenon. By inducing cation vacancies and heterostructures, a negative shift in the d‐band center gives rise to an increase in carrier concentration and promotion of charge separation, resulting in higher conductive and polarization losses, ultimately leading to a broader absorption bandwidth. The applicability of this concept is validated in another distinctly different system, where the absorption bandwidth also experiences a remarkable increase (from 0 to 6.86 GHz). This study offers significant implications for designing wide bandwidth EMW absorbers and expands their applications in various scenarios such as wearable electronics and artificial intelligent devices.
Doubling Power Conversion Efficiency of Si Solar Cells
Authors: Li Zhigang , Chen Yingda , Guo Renqing , Wang Shuang , Wang Weike , Wang Tianle , Zhao Shuaitao , Li Jiteng , Wu Jianbo , Jin Zhongwen , Wang Sihan , Wei Bingqing
Published: August 2024

Improving solar cells' power conversion efficiency (PCE) is crucial to further the deployment of renewable electricity. In addition, solar cells cannot function at exceedingly low temperatures owing to the carrier freeze‐out phenomenon. This report demonstrates that through temperature regulation, the PCE of monocrystalline single‐junction silicon solar cells can be doubled to 50–60% under monochromatic lasers and the full spectrum of AM 1.5 light at low temperatures of 30–50 K by inhibiting the lattice atoms' thermal oscillations for suppressing thermal loss, an inherent feature of monocrystalline Si cells. Moreover, the light penetration, determined by its wavelength, plays a critical role in alleviating the carrier freeze‐out effect and broadening the operational temperature range of silicon cells to temperatures as low as 10 K. Understanding these new observations opens tremendous opportunities for designing solar cells with even higher PCE to provide efficient and powerful energy sources for cryogenic devices and outer and deep space explorations.
Tailoring Polaron Dimensions in Lead‐Tin Hybrid Perovskites
Authors: Gao Lei , Zhang Heng , Zhang Yong , Fu Shuai , Geuchies Jaco J. , Valli Donato , Saha Rafikul Ali , Pradhan Bapi , Roeffaers Maarten , Debroye Elke , Hofkens Johan , Lu Junpeng , Ni Zhenhua , Wang Hai I. , Bonn Mischa
Published: August 2024

Charge carriers in the soft and polar perovskite lattice form so‐called polaron quasiparticles, charge carriers dressed with a lattice deformation. The spatial extent of a polaron is governed by the material's electron‐phonon interaction strength, which determines charge carrier effective mass, mobility, and the so‐called Mott polaron density, that is, the maximum stable density of charge carriers that a perovskite can support. Despite its significance, controlling polaron dimensions has been challenging. Here, experimental substantial tuning of polaron dimensions is reported by lattice engineering, through Pb/Sn substitution in CH3NH3SnxPb1−xI3. The polaron dimension is deduced from the Mott polaron density, which can be composition‐tuned over an order of magnitude, while charge carrier mobility occurs through band transport, and remains substantial across all compositions, ranging from 10 s to 100 s cm2 V s−1 at room temperature. The effective modulation of polaron size can be understood by considering the bond asymmetry after carrier injection as well as the random spatial distribution of Pb/Sn ions. This study underscores the potential for tailoring polaron dimensions, which is crucial for optimizing applications prioritizing either high charge carrier density or high mobility.
Water‐Templated Growth of Interfacial Superglue Polymers for Tunable Thin Films and In Situ Fluid Encapsulation
Authors: Jampani Venkata S. R. , Škarabot Miha , Mur Urban , Baigl Damien , Jonas Ulrich , Lagerwall Jan P. F. , Ravnik Miha , Anyfantakis Manos
Published: August 2024

Thin polymer films (TPFs) are indispensable elements in numerous technologies ranging from liquid encapsulation to biotechnology to electronics. However, their production typically relies on wet chemistry involving organic solvents or chemical vapor deposition, necessitating elaborate equipment and often harsh conditions. Here, an eco‐friendly, fast, and facile synthesis of water‐templated interfacial polymers based on cyanoacrylates (superglues, CAs) that yield thin films with tailored properties is demonstrated. Specifically, by exposing a cationic surfactant‐laden water surface to cyanoacrylate vapors, surfactant‐modulated anionic polymerization produces a manipulable thin polymer film with a thickness growth rate of 8 nm min−1. Furthermore, the shape and color of the film are precisely controlled by the polymerization kinetics, wetting conditions, and/or exposure to patterned light. Using various interfaces as templates for film growth, including the free surface of drops and soap bubbles, the developed method advantageously enables in situ packaging of chemical and biological cargos in liquid phase as well as the encapsulation of gases within solidified bubbles. Simple, versatile, and biocompatible, this technology constitutes a potent platform for programmable coating and soft/smart encapsulation of fluids.
Plasmonic Resonance Shifts in Gold Nanoparticles‐Thermochromic VO2 Thin Film Hybrid Platforms: A Joint Experimental and Numerical Study
Authors: Savorianakis Grégory , Rousseau Cédric , Sergievskaya Anastasiya , Rosolen Gilles , Voué Michel , Maes Bjorn , Konstantinidis S.
Published: August 2024

The combination of the phase transition in thermochromic vanadium dioxide (VO2) with plasmonic nanoparticles paves the way for applications in various fields, including optical sensing, advanced coatings, and dynamic optical devices. This study presents a simple fabrication method to control both the size and surface coverage of NPs combined with VO2. First, a thermochromic VO2 coating with a phase transition at 68 °C is synthesized using reactive magnetron sputtering. Then, monodisperse 30 nm diameter gold NPs are bonded to the VO2 surface using (3‐aminopropyl)trimethoxysilane (APTMS) linkers, examining the effect of immersion duration on surface coverage. Two platforms are developed: a VO2 thin film with a monolayer of NPs and a configuration with NPs between two VO2 films. The temperature‐dependent plasmonic response of these platforms is measured by extinction spectroscopy, showing a significant wavelength resonance shift of approximately 10 nm for the first platform and 20 nm for the second. Optical simulations analyze this shift over various geometries, from isolated NPs to fully covered NPs, achieving a 60 nm shift for NPs embedded in a thin VO2 film. This study demonstrates an effective approach to synthesizing thermochromic VO2 coatings with gold NPs, offering insights into the plasmonic properties of hybrid platforms.
Ultra‐Thin Metal Oxide Superstructure of Pd(001) as Passivation Interlayer at Organic/Metal Interface
Authors: Majumdar Isheta , Goto Francesco , Calloni Alberto , Duò Lamberto , Ciccacci Franco , Bussetti Gianlorenzo
Published: August 2024

At organic molecule/metal interfaces for electronic applications, it is required of the metal surface to be passivated in view of preserving the molecular properties of the ordered organic layer. This can be achieved by screening the metal with a single atomic layer of O, namely, ultra‐thin metal oxide (UTMO) layers. Cobalt tetraphenylporphyrins (CoTPP) on oxygen passivated Fe(001), with 1 ML O coverage, have revealed a molecule/substrate decoupling effect due to the formation of an ultra‐thin Fe oxide layer at the interface. However, the threshold concentration of surface O required to observe the decoupling effect has not been assessed yet. In this work, the possibility of stabilizing different ultra‐thin Pd oxide superstructures, characterized by a different number of O atoms per unit cell, is exploited to investigate the O decoupling effect on CoTPP films. Two Pd oxide superstructures are considered: Pd(001)‐p(2 × 2)O and Pd(001)‐p(√5 × √5)R27°O, with 0.25 and 0.80 ML O coverages, respectively, which are characterized by low‐energy electron diffraction (LEED), X‐ray and ultra‐violet photoelectron spectroscopies (XPS/UPS) and inverse photoemission spectroscopy (IPES). The results suggest a lower limit of 0.80 ML O coverage as a passivation interlayer to obtain an ordered and decoupled CoTPP monolayer on Pd(001).
Silica‐Rich Sol‐Gel Ink for Two‐Photon Direct Laser Writing of Microscale Structures and Optical Elements
Authors: Bin Nun Moran , Gvishi Raz , Dana Yoav , Garcia Yehudit , Marom Dan M. , Atar Nurit , Porat Omer , Bar Galit
Published: August 2024

Innovative materials enable two‐photon polymerization for precise additive fabrication of intricate optical components. Existing polymeric inks suffer from poor optical performance due to their high organic content. Silica‐rich sol‐gel ink (75 wt%, under ambient conditions) is presented for high‐precision three‐dimensional (3D) printing of microscale structures and optical devices. A photoinitiator with high‐efficiency nonlinear absorption is introduced to initiate two‐photon polymerization. Utilizing a commercial direct laser writing system, 3D‐printing is demonstrated including the optimization of printing parameters and ink characterization. The optical performance of the printed microscale elements using the new sol‐gel ink surpasses commercially available polymeric inks on key metrics: Printed elements exhibit extremely low surface roughness, 3nm; visible and near‐IR light transmission is greater than 90%; Printed elements present enhanced mechanical and chemical resistance to common organic solvents; Structures exhibit low isotropic shrinkage, <10%; Elements withstand continuous‐wave laser intensities exceeding 7 × 105 W cm−2. Direct writing onto an optical fiber tip with no need for surface functionalization is presented, with the demonstration of a tall waveguide taper (≈1:5 aspect ratio) with low losses and modal crosstalk, and a freestanding photonic lantern mode multiplexer. The new ink can be utilized in a variety of applications and across many materials, requiring compact, durable, and complex optical elements.
Photocatalyst‐Free Wavelength‐Dependant Sequential Ring Transformations of Pyrazolo[1,2‐a]pyrazolones
Authors: Kulašić Ines , Petek Nejc , Brodnik Helena , Grošelj Uroš , Svete Jurij , Štefane Bogdan
Published: August 2024

We report sequential wavelength‐selective photochemical transformations of 1‐alkenylpyrazolo[1,2‐a]pyrazolones to pyrazolo[1,2‐a][1,2]diazepines or cyclobuta[c]pyrazolo[1,2‐a]pyrazolones. Irradiation of 1‐alkenylpyrazolo[1,2‐a]pyrazolones with visible‐light (blue LED, 457 nm) induced selective ‘ring switching’ transformation into pyrazolo[1,2‐a][1,2]diazepines, which underwent electrocyclisation yielding cyclobuta[c]pyrazolo[1,2‐a]pyrazolones upon irradiation with UV−A light (black LED, 365 nm). Due to the very narrow irradiation wavelength now available from OLED sources, the selective formation of either 5,7‐bicyclic or 5,5,4‐tricyclic ring systems from the 5,5‐bicyclic starting material is possible by changing the wavelength of the irradiation source. The transformations took place under mild conditions in the absence of additives or photocatalysts. Mechanistic studies indicate that these transformations proceed through the formation of an excited triplet state of the substrate, followed by selective homolytic C(1)−N(8) bond cleavage, intersystem crossing, and cyclization of the zwitterionic intermediate on the ground potential energy surface. The subsequent photoinduced disrotatory stereospecific 4π‐electrocyclization of the 5,7‐bicyclic systems leads to 3D‐rich 5,5,4‐tricyclic products.
Visible‐Light‐Initiated Uranyl‐Catalyzed Hydrosilylation and Hydrosulfonylation of Alkenes and Alkynes
Authors: Gong Xingxing , Zhao Qianyi , Zhu Congqing
Published: August 2024

This study investigates the visible‐light‐initiated uranyl(VI)‐catalyzed activation of Si−H bonds through direct hydrogen atom transfer, which facilitates the formation of silyl radicals from silanes. The silyl radical can abstract a chlorine atom from the sulfonyl chloride, leading to the generation of sulfonyl radicals. These silyl radicals and sulfonyl radicals could react with alkenes and alkynes, achieving the first example of uranyl‐catalyzed hydrosilylation and hydrosulfonylation of unsaturated C−C bonds. This method features mild reaction conditions and a broad substrate scope, and exhibits exceptional functional‐group tolerance. Consequently, it is suitable for the late‐stage functionalization of drug derivatives.
Visible Light‐Induced Cyanomethyl Radical Triggered Cascade Cyclization of Phenyl‐Linked 1,6‐Enynes with a‐Halogenated Acetonitriles
Authors: Hu Xiao , Chen Bo‐Xin , Bo Xiang‐Lin , Zhang Qing‐Fang , Hu Lin‐Ping , Teng Ming‐Yu , Huang Guo‐Li , Liu Bo
Published: August 2024

Photo‐promoted cyanomethyl radical procedures for the preparation of 2,3‐dihydro‐1H‐indenes and 2,8‐dihydrocyclopenta[a]indenes from phenyl‐linked 1,6‐enynes with α‐halogenated acetonitriles are reported. The iodocyanomethylation/cyclization is performed via an atom‐transfer radical addition (ATRA) strategy under photocatalyst‐ and oxidant‐free conditions. In particular, the photoinduced cyanomethylative cascade bicyclization is carried out under the fac‐Ir(ppy)3/Na2CO3 catalystic symtem and visible light irradiation. These methods offer a one‐step and atom‐economical access to diverse cyano‐group containing five‐membered rings with broad substrate scope and high selectivity. A plausible reaction mechanism is also proposed.
History Matching Reservoir Models With Many Objective Bayesian Optimization
Authors: Samoil Steven , Fare Clyde , Jordan Kirk E. , Chen Zhangxin
Published: August 2024

Reservoir models for predicting subsurface fluid and rock behaviors can now include upwards of billions (and potentially trillions) of grid cells and are pushing the limits of computational resources. History matching, where models are updated to match existing historical data more closely, is conducted to reduce the number of simulation runs and is one of the primary time‐consuming tasks. As models get larger the number of parameters to match increases, and the number of objective functions increases, and traditional methods start to reach their limitations. To solve this, we propose the use of Bayesian optimization (BO) in a hybrid cloud framework. BO iteratively searches for an optimal solution in the simulations campaign through the refinement of a set of priors initialized with a set of simulation results. The current simulation platform implements grid management and a suite of linear solvers to perform the simulation on large scale distributed‐memory systems. Our early results using the hybrid cloud implementation shown here are encouraging on tasks requiring over 100 objective functions, and we propose integrating BO as a built‐in module to efficiently iterate to find an optimal history match of production data in a single package platform. This paper reports on the development of the hybrid cloud BO based history matching framework and the initial results of the application to reservoir history matching.
The role of hyperbranched polyesters in acrylamide‐based polymers as thickening agents in aqueous solutions
Authors: Meleán Brito Ramses S. , Padró Juan M. , Pinzón Barrantes John J. , Villa‐Pérez Cristian , Strumia Miriam C. , Milanesio Juan M. , Mattea Facundo
Published: August 2024

Acrylamide polymers are typically used in industrial and healthcare sectors as thickening agents; however, their thickening capabilities rely mainly in their molecular mass. A versatile and simple strategy to improve their performance is the copolymerization with specific monomers or their chemical modification with structures like dendritic or hyperbranched molecules. This study introduces a novel acrylamide‐acrylic acid polymer grafted with minor proportions (≤4.0 wt%) of Boltorn H30, a hyperbranched polyester monomer. The incorporation of Boltorn H30 aims to exploit the hyperbranched architecture's impact on the viscosity and rheological behavior of polymer solutions. Polymers with 0.4 and 4.0 polyester wt% characterized by several analytical techniques displayed improved viscosity in aqueous solution compared against the parent poly(acrylamide‐co‐acrylic acid). Results revealed that while the molecular mass distribution changed between 20% and 94%, the thickening capabilities significantly improved with increments of 2.7 and 3.8 times compared to that of the original polymers. These findings demonstrate that even with a minimal incorporation of hyperbranched polyesters, the abundance of hydroxyl groups fosters extensive hydrogen bonding, resulting in enhanced viscosity properties of the polymer.
Mutual Amplification of GLI2/Hedgehog and Transcription Factor JUN/AP‐1 Signaling in Fibroblasts in Systemic Sclerosis: Potential Implications for Combined Therapies
Authors: Bergmann Christina , Chenguiti Fakhouri Sara , Trinh‐Minh Thuong , Filla Tim , Rius Rigau Aleix , Ekici Arif B. , Merlevede Benita , Hallenberger Ludwig , Zhu Honglin , Dees Clara , Matei Alexandru‐Emil , Auth Janina , Györfi Andrea‐Hermina , Zhou Xiang , Rauber Simon , Bozec Aline , Dickel Nicholas , Liang Chunguang , Kunz Meik , Schett Georg , Distler Jörg H.W.
Published: August 2024

Objective

Deregulation of the cJUN/AP‐1 and hedgehog/GLI2 signaling pathways has been implicated in fibroblast activation in systemic sclerosis (SSc). However, the consequences of their concomitant up‐regulation are unknown. Here, we tested the hypothesis that mutual amplification of both pathways might drive persistent fibroblast activation.

Methods

Cultured fibroblasts and skin sections of patients with diffuse SSc and healthy volunteers were analyzed. cJUN/AP‐1 signaling and hedgehog/GLI2 signaling were inhibited using knockdown and pharmacologic approaches. Hedgehog signaling was activated in mice by fibroblast‐specific overexpression of constitutively active Smoothened.

Results

cJUN and GLI2 are concomitantly up‐regulated and colocalize in fibroblasts of patients with SSc compared to healthy controls. Activation of hedgehog/GLI2 signaling induces the expression of cJUN in vitro and in vivo, whereas inactivation of GLI2 inhibits cJUN expression. Likewise, inactivation of cJUN impairs the expression of GLI2. This mutual regulation occurs at the level of transcription with binding of cJUN and GLI2 to specific binding motifs. Interference with this mutual amplification of cJUN signaling and GLI2 signaling inhibits fibroblast activation and collagen release: Inhibition of cJUN/AP‐1 signaling ameliorates hedgehog‐induced fibroblast activation and skin fibrosis in SmoACT mice with a reduction of skin thickness of 103% (P = 0.0043) in the treatment group compared to the fibrotic control group. Moreover, combined pharmacologic inhibition of cJUN/AP‐1 and hedgehog/GLI2 exerts additive antifibrotic effects in a model of TGFβ‐driven experimental fibrosis (TBRACT mice).

Conclusion

The transcription factors cJUN and GLI2 reinforce each other's activity to promote fibroblast activation in SSc. Interruption of this crosstalk by combined inhibition of both pathways exerts additive antifibrotic effects at well‐tolerated doses.
Enhanced pitch discrimination in autistic children with unexpected bilingualism
Authors: Dumont Charlotte , Belenger Marie , Eigsti Inge‐Marie , Kissine Mikhail
Published: August 2024

Some autistic children acquire foreign languages from exposure to screens. Such unexpected bilingualism (UB) is therefore not driven by social interaction, rather, language acquisition appears to rely on less socially mediated learning and other cognitive processes. We hypothesize that UB children may rely on other cues, such as acoustic cues, of the linguistic input. Previous research indicates enhanced pitch processing in some autistic children, often associated with language delays and difficulties in forming stable phonological categories due to sensitivity to subtle linguistic variations. We propose that repetitive screen‐based input simplifies linguistic complexity, allowing focus on individual cues. This study hypothesizes that autistic UB children exhibit superior pitch discrimination compared with both autistic and non‐autistic peers. From a sample of 46 autistic French‐speaking children aged 9 to 16, 12 were considered as UB. These children, along with 45 non‐autistic children, participated in a two‐alternative forced‐choice pitch discrimination task. They listened to pairs of pure tones, 50% of which differed by 3% (easy), 2% (medium), or 1% (hard). A stringent comparison of performance revealed that only the autistic UB group performed above chance for tone pairs that differed, across all conditions. This group demonstrated superior pitch discrimination relative to autistic and non‐autistic peers. This study establishes the phenomenon of UB in autism and provides evidence for enhanced pitch discrimination in this group. Acute perception of auditory information, combined with repeated language content, may facilitate UB children's focus on phonetic features, and help acquire a language with no communicative support or motivation.
Ein konstitutives Modell zur Ermittlung der Ankertragfähigkeit auf der Grundlage des Distributed Strain Sensing in der Geotechnik
Authors: Kindler Arne
Published: August 2024

In den Jahren 2015–2017 hat sich der Verfasser im Rahmen seiner Tätigkeit als Leiter Forschung und Entwicklung bei der Stump‐Franki Spezialtiefbau GmbH dem Thema zukunftsweisende Messverfahren Distributed Strain Sensing in der Geotechnik gewidmet. Eine der ersten Entwicklungen war und ist das Monitoring von Verpresskörpern an Litzenverpressankern. Die seinerzeit neuen Erkenntnisse wurden u. a. international auf der DFI India, 2017 sowie auch national in der Bautechnik, 2017 und vor Ort auf dem 12. Hans‐Lorenz‐Symposium in Berlin, 2016 vorgetragen. So wurde gezeigt, dass die Messergebnisse der Dehnungsmessung mittels Distributed Strain Sensing genutzt werden können, um über die Folgejahre zu überprüfen, ob eine Überlastung der Verpressanker vorgekommen ist. Schon seinerzeit hat der Verfasser darauf hingewiesen, dass es zur richtigen Interpretation nicht nur ein Verständnis zu dem eingesetzten Messverfahren bedarf, sondern auch eines gewissen Erfahrungsschatzes in der Interpretation der Messergebnisse im unmittelbaren Zusammenhang mit der Geotechnik. Der Verfasser hat sich im Rahmen seiner Mitarbeit beim Normungsausschuss des DIN NA 005‐05‐17 AA Verpressanker, begleitet durch seine Erfahrungen aus der Praxis, vertiefend mit der Frage beschäftigt, was genau mittels Distributed Strain Sensing eigentlich in dem Verpresskörper gemessen wird und was aufgrund der Messergebnisse auf die Tragfähigkeit von Verpressankern geschlossen werden kann. Dieser Beitrag soll ein konstituierendes Modell beschreiben, auf dessen Grundlage weitere Entwicklungen zur Interpretation der Messergebnisse hinsichtlich der Nutzung des Distributed‐Strain‐Sensing‐Verfahrens als Nachweis der Wirtschaftlichkeit und der Ankertragfähigkeit möglich sind.