bluuebunny/crossref_metadata_2025 huggingface dataset:
Can oceanic paleothermometers reconstruct the Atlantic Multidecadal Oscillation?
Authors: Heslop D. , Paul A.
Published: March 2011

Abstract. Instrumental records of the North Atlantic sea surface temperature reveal a large-scale low frequency mode of variability that has become known as the Atlantic Multidecadal Oscillation (AMO). Proxy and modelling studies have demonstrated the important consequences of the AMO on other components of the climate system both within and outside the Atlantic region. Over longer time scales, the past behavior of the AMO is predominantly constrained by terrestrial proxies and only a limited number of records are available from the marine realm itself. Here we use an Earth System-Climate Model of intermediate complexity to simulate AMO-type behavior in the Atlantic with a specific focus placed on the ability of ocean paleothermometers to capture the associated surface and subsurface temperature variability. Given their lower prediction errors and annual resolution, coral-based proxies of sea surface temperature appear to be capable of reconstructing the temperature variations associated with the past AMO with an adequate signal-to-noise ratio. In contrast, the relatively high prediction error and low temporal resolution of sediment-based proxies, such as the composition of foraminiferal calcite, limits their ability to produce interpretable records of past temperature anomalies corresponding to AMO activity. Whilst the presented results will inevitably be model-dependent to some degree, the statistical framework is model-independent and can be applied to a wide variety of scenarios.
Regional climate model experiments to investigate the Asian monsoon in the Late Miocene
Authors: Tang H. , Micheels A. , Eronen J. , Fortelius M.
Published: March 2011

Abstract. The Late Miocene (11.6–5.3 Ma) is a crucial period for the Asian monsoon evolution. However, the spatiotemporal changes of the Asian monsoon system in the Late Miocene are still ambiguous, and the mechanisms responsible for these changes are debated. Here, we present a simulation of the Asian monsoon climate (0 to 60° N and 50 to 140° E) in the Tortonian (11–7 Ma) using the regional climate model CCLM3.2. We employ relatively high spatial resolution (1° × 1°) and adapt the physical boundary conditions such as topography, land-sea distribution and vegetation in the regional model to represent the Late Miocene. As climatological forcing, the output of a Tortonian run with a fully-coupled atmosphere-ocean general circulation model is used. Our results show a stronger-than-present E-Asian winter monsoon wind in the Tortonian, as a result of the enhanced mid-latitude westerly wind of our global forcing and the lowered northern Tibetan Plateau in the regional model. The summer monsoon circulation is generally weakened in our regional Tortonian run compared to today. However, the changes of summer monsoon precipitation exhibit major regional differences. The precipitation decreases in N-China and N-India, but increases in S-China, the western coast and the southern tip of India. This can be attributed to the combined effect of both the regional topographical changes and the other forcings related to our global model. The spread of the dry summer conditions over N-China and NW-India further implies that the monsoonal climate may not be fully established over these regions in the Tortonain. Compared with the global model, the high resolution regional model highlights the spatial differences of the Asian monsoon climate in the Tortonian, and better characterizes the convective activity and its response to topographical changes. It therefore provides a useful and compared to global models complementary tool to improve our understanding of the Asian monsoon evolution in the Late Miocene.
Boron isotope fractionation during brucite deposition from artificial seawater
Authors: Xiao J. , Xiao Y. K. , Liu C. Q. , Jin Z. D.
Published: March 2011

Abstract. Experiments involving boron incorporation into brucite (Mg(OH)2) from magnesium-free artificial seawater with pH values ranging from 9.5 to 13.0 were carried out to better understand the incorporation behavior of boron into brucite. The results show that both concentration of boron in deposited brucite ([B]d) and its boron partition coefficient (Kd) between deposited brucite and final seawater are controlled by pH of the solution. The incorporation capacity of boron into brucite is much stronger than that into oxides and clay minerals. The isotopic compositions of boron in deposited brucite (δ11Bd) are higher than those in the associated artificial seawater (δ11Bisw) with fractionation factors ranging between 1.0177 and 1.0569, resulting from the preferential incorporation of B(OH)3 into brucite. Both boron adsorptions onto brucite and precipitation reaction of H3BO3 with brucite exist during deposition of brucite from artificial seawater. The simultaneous occurrence of both processes determines the boron concentration and isotopic fractionation of brucite. The isotopic fractionation behaviors and mechanisms of boron incorporated into brucite are different from those into carbonates. Furthermore, the isotopic compositions of boron in modern corals might be affected by the existence of brucite in madrepore and the preferential incorporation of B(OH)3 into brucite. An exploratory study for the influence of brucite on the boron isotopic composition in modern corals is justifiable.
Past surface temperatures at the NorthGRIP drill site from the difference in firn diffusion of water isotopes
Authors: Simonsen S. B. , Johnsen S. J. , Popp T. J. , Vinther B. M. , Gkinis V. , Steen-Larsen H. C.
Published: March 2011

Abstract. A new ice core paleothermometer is introduced based on the temperature dependent diffusion of the stable water isotopes in the firn. A new parameter called differential diffusion length is defined as the difference between the diffusion length of the two stable water isotopes 18O and deuterium. A model treatment of the diffusion process of the firn and the ice is presented along with a method of retrieving the diffusion signal from the ice core record of water isotopes using spectral methods. The model shows how the diffusion process is highly dependent on the inter-annual variations in the surface temperatures resulting in a longer diffusion length than by assuming an isothermal firn. The longer diffusion length can be explained by the strong non-linearly behavior of the saturation pressure over ice in the range of the surface temperature fluctuations. The method has been tested on δ18O and δD measurements, spanning the transition from the last glacial to the holocene, from the NorthGRIP ice core. The surface temperature reconstruction based on the differential diffusion resembles other temperature reconstructions for the NorthGRIP ice core. However, the Allerød warming is seen to be significantly warmer than observed in other ice core based temperature reconstructions. The mechanisms behind this behavior are not fully understood. The method shows the need of an expansion of high resolution stable water isotopes data sets from ice cores. However, the new ice core paleothermometer presented here will give valuable insight in past climate, through the physical process of isotope diffusion in the firn column of ice sheets.
Assessing the sources of uncertainty associated with the calculation of rainfall kinetic energy and erosivity – application to the Upper Llobregat Basin, NE Spain
Authors: Catari G. , Latron J. , Gallart F.
Published: March 2011

Abstract. The diverse sources of uncertainty associated with the calculation of rainfall kinetic energy and rainfall erosivity, calculated from precipitation data, were investigated at a range of temporal and spatial scales in a mountainous river basin (504 km2) in the south-eastern Pyrenees. The sources of uncertainty analysed included both methodological and local sources of uncertainty and were (i) tipping-bucket rainfall gauge instrumental errors, (ii) the efficiency of the customary equation used to derive rainfall kinetic energy from intensity, (iii) the efficiency of the regressions obtained between daily precipitation and rainfall erosivity, (iv) the temporal variability of annual rainfall erosivity values, and the spatial variability of (v) annual rainfall erosivity values and (vi) long-term erosivity values. The differentiation between systematic (accuracy) and random (precision) errors was taken into account in diverse steps of the analysis. The results showed that the uncertainty associated with the calculation of rainfall kinetic energy from rainfall intensity at the event and station scales was as high as 30%, because of insufficient information on rainfall drop size distribution. This methodological limitation must be taken into account for experimental or modelling purposes when rainfall kinetic energy is derived solely from rainfall intensity data. For longer temporal scales, the relevance of this source of uncertainty remained high if low variability in the types of rain was supposed. Temporal variability of precipitation at wider spatial scales was the main source of uncertainty when rainfall erosivity was calculated on an annual basis, whereas the uncertainty associated with long-term erosivity was rather low and less important than the uncertainty associated with other model factors such as those in the RUSLE, when operationally used for long-term soil erosion modelling.
The influence of soil moisture on threshold runoff generation processes in an alpine headwater catchment
Authors: Penna D. , Tromp-van Meerveld H. J. , Gobbi A. , Borga M. , Dalla Fontana G.
Published: March 2011

Abstract. This study investigates the role of soil moisture on the threshold runoff response in a small headwater catchment in the Italian Alps that is characterised by steep hillslopes and a distinct riparian zone. This study focuses on: (i) the threshold soil moisture-runoff relationship and the influence of catchment topography on this relation; (ii) the temporal dynamics of soil moisture, streamflow and groundwater that characterize the catchment's response to rainfall during dry and wet periods; and (iii) the combined effect of antecedent wetness conditions and rainfall amount on hillslope and riparian runoff. Our results highlight the strong control exerted by soil moisture on runoff in this catchment: a sharp threshold exists in the relationship between soil water content and runoff coefficient, streamflow, and hillslope-averaged depth to water table. Low runoff ratios were likely related to the response of the riparian zone, which was almost always close to saturation. High runoff ratios occurred during wet antecedent conditions, when the soil moisture threshold was exceeded. In these cases, subsurface flow was activated on hillslopes, which became a major contributor to runoff. Antecedent wetness conditions also controlled the catchment's response time: during dry periods, streamflow reacted and peaked prior to hillslope soil moisture whereas during wet conditions the opposite occurred. This difference resulted in a hysteretic behaviour in the soil moisture-streamflow relationship. Finally, the influence of antecedent moisture conditions on runoff was also evident in the relation between cumulative rainfall and total stormflow. Small storms during dry conditions produced low stormflow amounts, likely mainly from overland flow from the near saturated riparian zone. Conversely, for rainfall events during wet conditions, higher stormflow values were observed and hillslopes must have contributed to streamflow.
Quantifying spatial and temporal discharge dynamics of an event in a first order stream, using Distributed Temperature Sensing
Authors: Westhoff M. C. , Bogaard T. A. , Savenije H. H. G.
Published: March 2011

Abstract. Understanding spatial distribution of discharge can be important for water quality and quantity modeling. Non-steady flood waves can influence small headwater streams significantly, particularly as a result of short high intensity summer rainstorms. The aim of this paper is to quantify the spatial and temporal dynamics of stream flow in a headwater catchment during a summer rainstorm. These dynamics include gains and losses of stream water, the effect of bypasses that become active and hyporheic exchange fluxes that may vary over time as a function of discharge. We use an advection-dispersion model coupled with an energy balance model to simulate in-stream water temperature, which we confront with high resolution temperature observations obtained with Distributed Temperature Sensing. This model was used as a learning tool to stepwise unravel the complex puzzle of in-stream processes subject to varying discharge. Hypotheses were tested and rejected, which led to more insight in spatial and temporal dynamics in discharge and hyporheic exchange processes. We showed that infiltration losses increase during a rain event, while gains of water remained constant over time. We conclude that, eventually, part of the stream water bypassed the main channel during peak discharge. It also seems that hyporheic exchange varies with varying discharge in the first 250 of the stream; while further downstream it remains constant. Because we relied on solar radiation as the main energy input, we were only able to apply this method during a small event and low flow. However, when additional (artificial) energy is available, the presented method is also applicable in larger streams, or during higher flow conditions.
Impact of climate change on groundwater point discharge: backflooding of karstic springs (Loiret, France)
Authors: Joigneaux E. , Albéric P. , Pauwels H. , Pagé C. , Terray L. , Bruand A.
Published: March 2011

Abstract. Under certain hydrological conditions it is possible for spring flow in karst systems to be reversed. When this occurs, the resulting invasion by surface water, i.e. the backflooding, represents a serious threat to groundwater quality because the surface water could well be contaminated. Here we examine the possible impact of future climate change on the occurrences of backflooding in a specific karst system, having first established the occurrence of such events in the selected study area over the past 40 yr. It would appear that backflooding has been more frequent since the 1980s, and that it is apparently linked to river flow variability on the pluri-annual scale. The avenue that we adopt here for studying recent and future variations of these events is based on a downscaling algorithm relating large-scale atmospheric circulation to local precipitation spatial patterns. The large-scale atmospheric circulation is viewed as a set of quasi-stationary and recurrent states, called weather types, and its variability as the transition between them. Based on a set of climate model projections, simulated changes in weather-type occurrence for the end of the century suggests that backflooding events can be expected to decrease in 2075–2099. If such is the case, then the potential risk for groundwater quality in the area will be greatly reduced compared to the current situation. Finally, our results also show the potential interest of the weather-type based downscaling approach for examining the impact of climate change on hydrological systems.
The Indus basin in the framework of current and future water resources management
Authors: Laghari A. N. , Vanham D. , Rauch W.
Published: March 2011

Abstract. The Indus basin is one of the regions in the world that is faced with major challenges for its water sector, due to population growth, rapid urbanisation and industrialisation, environmental degradation, unregulated utilization of the resources, inefficient water use and poverty, all aggravated by climate change. This paper gives a comprehensive listing and description of available options for current and future sustainable water resources management (WRM) within the basin. Sustainable WRM practices include both water supply management and water demand management options.
First investigations of an ice core from Eisriesenwelt cave (Austria)
Authors: May B. , Spötl C. , Wagenbach D. , Dublyansky Y. , Liebl J.
Published: March 2011

Abstract. Investigations into the genesis and dynamical properties of cave ice are essential for assessing the climate significance of these underground glaciers. We drilled an ice core through a 7.1 m-thick ice body filling a large cavern of the dynamic ice cave Eisenriesenwelt (Austria). In addition to visual core inspections, quasi-continuous measurements at 2 cm resolution comprised particulate matter, stable water isotope (δ18O, δD) and electrolytic conductivity profiles supplemented by specifically selected samples analyzed for tritium and radiocarbon. We found that recent ablation led to an almost complete loss of bomb-derived tritium removing any ice accumulated since, at least, the early fifties leaving the actual ice surface even below the natural tritium level. The small particulate organic masses rendered radiocarbon dating inconclusive, though a crude estimate gave a basal ice age in the order of several thousand years. The visual stratigraphy and all investigated parameters showed a clear dichotomy between the upper 2 m and the bottom 3 m of the core, which points to a substantial change in the ice formation process. Main features of the core comprise the changing appearance and composition of distinct cryocalcite layers, extremely low total ion content and a surprisingly high variability of the isotope signature. Co-isotope evaluation (δD versus δ18O) of the core in comparison with data from precipitation and karst spring water clearly indicate that ice formation is governed by (slow) freezing of dripping water.
Retrieval of snow grain size and albedo of Western Himalayan snow cover using satellite data
Authors: Negi H. S. , Kokhanovsky A.
Published: March 2011

Abstract. In the present study we describe the retrievals of snow grain size and spectral albedo (plane and spherical albedo) for Western Himalayan snow cover using Hyperion sensor data. The asymptotic radiative transfer (ART) theory was explored for the snow retrievals. To make the methodology operational only five spectral bands (440, 500, 1050, 1240 and 1650 nm) of Hyperion were used for snow parameters retrieval. The bi-spectral method (440 nm in the visible and 1050/1240 nm in the NIR region) was used to retrieve snow grain size. Spectral albedos were retrieved using satellite reflectances and estimated grain size. A good agreement was observed between retrieved snow parameters and ground observed snow-meteorological conditions. The satellite retrieved grain sizes were compared with field spectroradiometer retrieved grain sizes and close results were found for Lower Himalayan snow. The wavelength 1240 nm was found to be more suitable compared to 1050 nm for grain size retrieval along the steep slopes. The methodology was able to retrieve the spatial variations in snow parameters in different parts of Western Himalaya which are due to snow climatic and terrain conditions of Himalaya. This methodology is of importance for operational snow cover and glacier monitoring in Himalayan region using space-borne and air-borne sensors.
Temperature variability and thermal offset in steep alpine rock and ice faces
Authors: Hasler A. , Gruber S. , Haeberli W.
Published: March 2011

Abstract. The thermal condition of high-alpine mountain flanks can be an important determinant of climate change impact on slope stability and correspondingly down-slope hazard regimes. In this study we analyze new time-series from 17 shallow temperature-depth profiles at two field sites in steep bedrock and ice. Extending earlier studies that revealed the topographic variations in temperatures, we demonstrate considerable differences of annual mean temperatures for variable surface characteristics and depths within the measured profiles. This implies that measurements and models related to compact and near-vertical bedrock temperatures may deviate considerably from conditions in the majority of bedrock slopes in mountain ranges that are usually non-vertical and fractured. For radiation-exposed faces, for instance, mean annual temperatures at depth are up to 3 °C lower and permafrost is likely to exist at lower elevations than reflected by current estimates based on the near-vertical case. Retention of thin snow cover and ventilation effects in open clefts are most likely responsible for this cooling. The presented or similar data could be used in the future to support the development and testing of models related to the thermal influence of snow-cover and fractures in steep bedrock. This would allow generalizing the here-presented findings.
Solutions for Lipophilic Drugs: A Biodegradable Polymer Acting as Solvent, Matrix, and Carrier to Solve Drug Delivery Issues
Authors: Asmus Lutz R. , Gurny Robert , Möller Michael
Published: March 2011

The purpose of this study was to investigate the polyester hexylsubstituted poly(lactide) (hexPLA) as a possible solvent for lipophilic substances and excipient for pharmaceutical formulations. HexPLA is a biodegradable and semi-solid polymer, which allows the incorporation of active substances by simple mixing and local or systemic application to the patient through injection. The solvent behavior of hexPLA was investigated by adding the lipophilic dye Sudan III to the polymer matrix and optical monitoring of the dissolution process over time by microscopy. As a drug, the antipsychotic compound Haloperidol was analyzed for its solubility in hexPLA of different molecular weights by preparing saturated solutions, and measuring the amount of incorporated drug with UV spectroscopy. The influence of the rate of solubilized to suspended drug on the burst release behavior of Haloperidol from hexPLA-formulations was investigated in release tests. It is demonstrated that hexPLA dissolves both lipophilic substances, Sudan III and Haloperidol. In the molecular weight range between 2,000 g/mol and 10,000 g/mol, a lower molecular weight hexPLA resulted in a higher incorporation capacity for Haloperidol. By changing from a suspension formulation of Haloperidol to a solution formulation, the initial burst release established for classical PLA and PLGA systems could be minimized. HexPLA is shown to be a potent solvent and excipient for lipophilic drugs, allowing the initial burst of drug release to be modified and controlled.
Controlling Fibroblast Adhesion with Ph Modified Polyelectrolyte Multilayers
Authors: Niepel Marcus S. , Peschel Dieter , Groth Thomas
Published: March 2011

Tissue cells need to adhere to a biomaterial surface to promote their growth and differentiation and, thus, foster the integration of implants. As a result, surface features and their modification play an important role in biomedical applications. In this study, the layer-by-layer (LbL) technique was used to design self-assembled polyelectrolyte multilayer (PEM) coatings of polyethyleneimine (PEI) and heparin (HEP) on glass, which will control the adhesion of primary human dermal fibroblasts in a model system. The study showed that, among other surface features, the wettability of surfaces can be controlled by changing the conditions during multilayer self-assembly. Here, the pH value of the HEP solution was adjusted to acidic or alkaline values for terminal layers, which also led to a change in multilayer growth. Further, the study revealed that plain terminal layers were rather cytophobic. Upon pre-adsorption of fibronectin (FN), a clear effect on cell adhesion and morphology in dependence on the pH setup was evident. Proliferation studies clearly showed that terminal layers, which impaired cell adhesion, also inhibited growth of human fibroblasts under serum-conditions. On the other hand, on layers with pronounced cell adhesion an elevated cell growth was also observed. As a result, HEP terminated multilayers are interesting for applications requiring cell repellent properties, whereas PEI terminated multilayers could be used to promote cell adhesion and growth on implant surfaces.
Evaluation of Tubular Poly(Trimethylene Carbonate) Tissue Engineering Scaffolds in a Circulating Pulsatile Flow System
Authors: Song Yan , Wennink Jos W.H. , Poot Andre A. , Vermes Istvan , Feijen Jan , Grijpma Dirk W.
Published: March 2011

Tubular scaffolds (internal diameter approximately 3 mm and wall thickness approximately 0.8 mm) with a porosity of approximately 83% and an average pore size of 116 μm were prepared from flexible poly(trimethylene carbonate) (PTMC) polymer by dip-coating and particulate leaching methods. PTMC is a flexible and biocompatible polymer that crosslinks upon irradiation; porous network structures were obtained by irradiating the specimens in vacuum at 25 kGy before leaching soluble salt particles. To assess the suitability of these scaffolds in dynamic cell culturing for cardiovascular tissue engineering, the scaffolds were coated with a thin (0.1 to 0.2 mm) non-porous PTMC layer and its performance was evaluated in a closed pulsatile flow system (PFS). For this, the PFS was operated at physiological conditions at liquid flows of 1.56 ml/s with pressures varying from 80–120 mmHg at a frequency of 70 pulsations per minute.

The mechanical properties of these coated porous PTMC scaffolds were not significantly different than non-coated scaffolds. Typical tensile strengths in the radial direction were 0.15 MPa, initial stiffness values were close to 1.4 MPa. Their creep resistance in cyclic deformation experiments was excellent. In the pulsatile flow setup, the distention rates of these flexible and elastic scaffolds were approximately 0.10% per mmHg, which is comparable to that of a porcine carotid artery (0.11% per mmHg). The compliance and stiffness index values were close to those of natural arteries.

In long-term deformation studies, where the scaffolds were subjected to physiological pulsatile pressures for one week, the morphology and mechanical properties of the PTMC scaffolds did not change. This suggests their suitability for application in a dynamic cell culture bioreactor.
Preparation and Evaluation of Hydrogel-Composites from Methacrylated Hyaluronic Acid, Alginate, and Gelatin for Tissue Engineering
Authors: Möller Lena , Krause Andreas , Dahlmann Julia , Gruh Ina , Kirschning Andreas , Dräger Gerald
Published: March 2011

Hydrogels are three-dimensional water-insoluble hydrophilic natural or synthetic polymer networks made up of crosslinked water-soluble polymers. The purpose of this study was to develop and directly compare photo crosslinked hydrogels on the basis of pure gelatin, alginate and hyaluronic acid as well as their blends. The functionalization of starting materials with methacrylate moieties was evaluated by 1H-NMR spectroscopy. Hydrogels were prepared from methacrylates by photo cross-linking using UV light. The effect of changing the hydrogel composition was quantified through examination of hydrogel swelling behavior and rheological properties. In addition, the viability and adhesion of neonatal rat cardiomyocytes (NRCM) seeded onto the hydrogels was examined by in vivo imaging of NRCM-mediated scaffold contraction as well as by histological evaluation after immunostaining. Biological testing showed good biocompatibility and cell survival in the presence of all materials discussed. Adhesion of cells could only be observed in the presence of gelatin. Blends of gelatin, alginate and hyaluronic acid are promising candidates for the generation of non-toxic, biocompatible hydrogel scaffolds for tissue engineering. Variation of individual compound ratios in the blends can be used for a precise control of mechanical properties and may allow wide-ranging uses in various tissue engineering applications with different mechanical requirements.
Current Status of Langmuir Monolayer Degradation of Polymeric Biomaterials
Authors: Reiche Juergen , Kratz Karl , Hofmann Dieter , Lendlein Andreas
Published: March 2011

Langmuir monolayer degradation (LMD) experiments with polymers possessing outstanding biomedical application potential yield information regarding the kinetics of their hydrolytic or enzymatic chain scission under well-defined and adjustable degradation conditions. A brief review is given of LMD investigations, including the author's own work on 2-dimensional (2D) polymer systems, providing chain scission data, which are not disturbed by simultaneously occurring transport phenomena, such as water penetration into the sample or transport of scission fragments out of the sample.

A knowledge-based approach for the description and simulation of polymer hydrolytic and enzymatic degradation based on a combination of fast LMD experiments and computer simulation of the water penetration is briefly introduced. Finally, the advantages and disadvantages of this approach are discussed.
Degradable Depsipeptide-Based Multiblock Copolymers with Polyester or Polyetherester Segments
Authors: Feng Yakai , Lu Jian , Behl Marc , Lendlein Andreas
Published: March 2011

Polydepsipeptides, alternating copolymers of an α-amino acid and a α-hydroxy acid, are an interesting group of degradable polymers. They have gained attention as potential degradable implant materials. Polydepsipeptides are expected to have better biocompatibility in vivo during the degradation process than aliphatic polyesters. Various depsipeptide-based polymers with or without pendant functional groups have been synthesized via ring-opening polymerization of corresponding morpholine-2,5-dione derivatives. The different polymer architectures of the polymers, for example, providing an alternating, random, diblock, triblock, or multiblock structure, can be obtained by appropriate selection of the polymerization reaction, which may be ring-opening or polyaddition. Recently, we synthesized thermoplastic phase-segregated copolymers with a multiblock structure containing polydepsipeptides and poly(∊-caprolactone) or poly(p-dioxanone) segments via coupling of the respective diols using an aliphatic diisocyanate. The obtained multiblock copolymers showed good elastic properties at 25°C and 75°C. Furthermore, they exhibited a shape-memory capability. Here, we summarize the synthesis, biodegradation behavior and shape-memory properties of the multiblock copolymers. In addition, we introduce new combinations of depsipeptide/poly(ether)ester segments in multiblock copolymers. The depsipeptide-based multiblock copolymers have potential applications as biomaterials for controlled drug release, tissue engineering scaffolds, or base materials for biofunctional implants.
Trust and 2024 Public Priorities for the CDC and State Health Departments
Authors: SteelFisher Gillian K. , Findling Mary G. , Caporello Hannah L. , Boyea Alyssa , Espino Laura , Sutton Jazmyne
Published: May 2024

This survey study evaluates public health priorities and trust in the Centers for Disease Control and Prevention (CDC) and state health departments among US adults after the COVID-19 pandemic.
COVID-19 Admission Rates and Changes in Care Quality in US Hospitals
Authors: Meille Giacomo , Owens Pamela L. , Decker Sandra L. , Selden Thomas M. , Miller Melissa A. , Perdue-Puli Jade K. , Grace Erin N. , Umscheid Craig A. , Cohen Joel W. , Valdez R. Burciaga
Published: May 2024

Importance

Unprecedented increases in hospital occupancy rates during COVID-19 surges in 2020 caused concern over hospital care quality for patients without COVID-19.

Objective

To examine changes in hospital nonsurgical care quality for patients without COVID-19 during periods of high and low COVID-19 admissions.

Design, Setting, and Participants

This cross-sectional study used data from the 2019 and 2020 Agency for Healthcare Research and Quality’s Healthcare Cost and Utilization Project State Inpatient Databases. Data were obtained for all nonfederal, acute care hospitals in 36 states with admissions in 2019 and 2020, and patients without a diagnosis of COVID-19 or pneumonia who were at risk for selected quality indicators were included. The data analysis was performed between January 1, 2023, and March 15, 2024.

Exposure

Each hospital and week in 2020 was categorized based on the number of COVID-19 admissions per 100 beds: less than 1.0, 1.0 to 4.9, 5.0 to 9.9, 10.0 to 14.9, and 15.0 or greater.

Main Outcomes and Measures

The main outcomes were rates of adverse outcomes for selected quality indicators, including pressure ulcers and in-hospital mortality for acute myocardial infarction, heart failure, acute stroke, gastrointestinal hemorrhage, hip fracture, and percutaneous coronary intervention. Changes in 2020 compared with 2019 were calculated for each level of the weekly COVID-19 admission rate, adjusting for case-mix and hospital-month fixed effects. Changes during weeks with high COVID-19 admissions (≥15 per 100 beds) were compared with changes during weeks with low COVID-19 admissions (<1 per 100 beds).

Results

The analysis included 19 111 629 discharges (50.3% female; mean [SD] age, 63.0 [18.0] years) from 3283 hospitals in 36 states. In weeks 18 to 48 of 2020, 35 851 hospital-weeks (36.7%) had low COVID-19 admission rates, and 8094 (8.3%) had high rates. Quality indicators for patients without COVID-19 significantly worsened in 2020 during weeks with high vs low COVID-19 admissions. Pressure ulcer rates increased by 0.09 per 1000 admissions (95% CI, 0.01-0.17 per 1000 admissions; relative change, 24.3%), heart failure mortality increased by 0.40 per 100 admissions (95% CI, 0.18-0.63 per 100 admissions; relative change, 21.1%), hip fracture mortality increased by 0.40 per 100 admissions (95% CI, 0.04-0.77 per 100 admissions; relative change, 29.4%), and a weighted mean of mortality for the selected indicators increased by 0.30 per 100 admissions (95% CI, 0.14-0.45 per 100 admissions; relative change, 10.6%).

Conclusions and Relevance

In this cross-sectional study, COVID-19 surges were associated with declines in hospital quality, highlighting the importance of identifying and implementing strategies to maintain care quality during periods of high hospital use.
l‐2‐Aminopimelic acid acts as an auxin mimic to induce lateral root formation across diverse plant species
Authors: Tabeta Hiromitsu , Hirai Masami Y.
Published: May 2024

The identification of chemicals that modulate plant development and adaptive responses to stresses has attracted increasing attention for agricultural applications. Recent basic studies have identified functional amino acids that are essential for plant organogenesis, indicating that amino acids can regulate plant growth. In this study, we newly identified 2‐aminopimelic acid (2APA), a nonproteinogenic amino acid, as a novel bioactive compound involved in root morphogenesis. This biological effect was confirmed in several plant species. Our phenotypic analysis revealed that the bioactive 2APA is an l‐form stereoisomer. Overall, our study identified a promising root growth regulator and provided insight into the intricate metabolism related to root morphology.
Detecting flowers on imagery with computer vision to improve continental scale grassland biodiversity surveying
Authors: Elvekjaer N. , Martinez‐Sanchez L. , Bonnet P. , Joly A. , Paracchini M. L. , van der Velde M.
Published: May 2024

Large‐scale biodiversity monitoring is essential for assessing biodiversity trends, yet traditional surveying methods are limited in the spatial/temporal scale they can cover. Recent technological developments have led to computer vision‐based species identification tools, such as the Pl@ntNet application. Increasing accuracy of such algorithms presents an opportunity of integrating computer vision into larger monitoring schemes and could lead to automating ground‐based evidence provision related to agri‐environmental measures (e.g. flower strips, field margins). However, images from surveys or farmer declarations do not live up to the standards of current applications. In order to integrate these automated methods into biodiversity monitoring, more generalized models are needed.

We create a dataset using 500 manually delineated images of vegetation patches in European grasslands taken during the Land Use/cover Area Survey (LUCAS) grassland module. We train the Faster R‐CNN model to detect and extract individual flower objects. Using this model, we extract the abundance of flowers in an image, analyse their colour distribution, and use the Pl@ntNet application to identify the species of the individual flowers detected.

The best model reaches precision and recall of 0.89/0.61 and predicts 1377 flowers on the 100 test images distributed between 10 colours. Using Pl@ntNet, only 52 flowers were identified with a certainty score above 0.5 due to the limitations in image size and quality. Of these flowers, 30% were correctly automatically identified at the species level and 42% at the genus level.

The results show that we can automatically extract valuable information on floral abundances, colours, and sizes from images of vegetation patches, though in most cases better images are needed for species identification. Despite limitations with image quality, integrating this workflow into large‐scale monitoring could speed up the sampling process and allow for better spatial and temporal data on floral diversity and abundance.
A quality‐related distributed process monitoring framework for large‐scale manufacturing processes with multirate sampling measurements
Authors: Dong Jie , Yang Kaixuan , Zhang Hongjun , Zhang Chi , Peng Kaixiang
Published: May 2024

Quality‐related process monitoring has become a research hot‐spot in the field of industrial control because it is essential to ensure the process safety and product quality. A great number of data driven quality‐related process monitoring methods have been developed for large‐scale manufacturing processes, and most of them are developed based on homogeneous sampling measurement. Therefore, it is necessary to develop quality‐related monitoring methods for large‐scale processes with multirate sampling measurements. In this paper, a new quality‐related distributed monitoring framework for large‐scale manufacturing processes with multirate sampling measurements is proposed. First, a new subsystem decomposition method for multirate sampling processes combining prior knowledge and mutual information is proposed by introducing mathematic expectations. Second, local monitoring model is designed for each subsystem. Multirate partial least squares regression is adopted for modeling among the process and quality variables. The monitoring metrics of the isolation‐based anomaly detection using nearest‐neighbor ensembles are built in prediction space and process space, respectively. Finally, Bayesian inference is introduced to obtain statistical indicators for the plant‐wide processes. The validity of the proposed framework is verified in Tennessee Eastman process and a real hot strip mill process. The results show that the proposed method has favorable effectiveness and significant performance gains compared with state‐of‐the‐art methods.
Enhancing Desorption Performance of a Compressible Hybrid Structured Adsorbent via Localized Magnetic Induction Heating
Authors: Schoukens Matthias , Sharma Ravi , Laha Priya , Hauffman Tom , Van Assche Tom R.C. , Denayer Joeri F.M.
Published: May 2024

Structured adsorbents have gained significant importance in gas separation applications due to their ability to fine‐tune mass and heat transfer and lower pressure drop across the bed. This study presents a ferromagnetic compressible hybrid structured adsorbent, allowing regeneration via magnetic induction heating. A compressible melamine sponge is coated with the CO2‐selective Ni‐MOF‐74 adsorbent and Fe3O4 as a ferromagnetic susceptor, capable of dissipating heat instantaneously in an alternating electromagnetic field. Taking advantage of these properties, the potential of rapid CO2 capture and thermal regeneration via magnetic induction swing adsorption is investigated. The successful incorporation of both ingredients on the melamine sponge is confirmed via SEM‐EDX and XRD analysis. Breakthrough experiments with a CO2/CH4‐mixture are performed. The selective property of Ni‐MOF‐74 toward CO2 is retained, with the composite showing a capacity of 1.89 mmol CO2/g. The compressible nature of the melamine sponge allowed for an improvement of 79% in the volumetric capacity of the adsorbent bed and a higher heating rate. In regard to regeneration, within 1 min of subjecting the structured composite to the alternating magnetic field, an efficient desorption (>90%) of CO2 is achieved. Overall, a ferromagnetic compressible hybrid structured adsorbent is presented for fast cyclic gas‐phase separation processes.
Robustness and Tunability of Symmetric‐Protected Bound States in the Continuums and Quasi‐Bound States in the Continuums in Terahertz Metasurfaces
Authors: Ji Jie , Zhou Binbin , Bøggild Peter , Al‐Daffaie Shihab , Jepsen Peter Uhd , Gomez Rivas Jaime
Published: May 2024

Symmetry‐protected bound states in the continuum (BICs), emerging at the point in the Brillouin zone of periodic lattices of scatters, are robust optical modes under modifications in the lattice if the C2 symmetry (two fold rotational symmetry) is preserved. In this study, the manipulation of these symmetry‐protected BIC and quasi‐BIC modes in a system comprising two metallic rods per unit cell by adjusting their lateral separation and displacement is focused on. With non‐symmetric systems under 180° rotation, two distinct coupling mechanisms resulting from changes in the lateral separation are investigated: the coupling of two half‐wavelength (λ/2) resonances and the coupling of two surface lattice resonances (SLRs). Notably, symmetric structures with minimal lateral separation cannot sustain BIC modes owing to the near‐field coupling between the rods. However, when the lateral separation is sufficiently large, the existence of a BIC mode supported by an SLR remains robust even with positional shifts. Furthermore, increasing the lateral separation and the shift displacement between the rods in asymmetric systems induces a redshift and a blueshift in the quasi‐BIC mode, respectively. This shift is attributed to the near‐field coupling effect between two rods, enabling the tunability of the resonance frequency with a high‐quality factor.
Bimerons create bimerons: Proliferation and aggregation induced by currents and magnetic fields
Authors: Zhang Xichao , Zhou Yan , Yu Xiuzhen , Mochizuki Masahito
Published: May 2024

The aggregation of topological spin textures at nano and micro scales has practical applications in spintronic technologies. Here, the authors report the in‐plane current‐induced proliferation and aggregation of bimerons in a bulk chiral magnet. It is found that the spin‐transfer torques can induce the proliferation and aggregation of bimerons only in the presence of an appropriate out‐of‐plane magnetic field. It is also found that a relatively small damping and a relatively large non‐adiabatic spin‐transfer torque could lead to more pronounced bimeron proliferation and aggregation. Particularly, the current density should be larger than a certain threshold in order to trigger the proliferation; namely, the bimerons may only be driven into translational motion under weak current injection. Besides, the authors find that the aggregate bimerons could relax into a deformed honeycomb bimeron lattice with a few lattice structure defects after the current injection. The results are promising for the development of bio‐inspired spintronic devices that use a large number of aggregate bimerons. The findings also provide a platform for studying aggregation‐induced effects in spintronic systems, such as the aggregation‐induced lattice phase transitions.
Tuning the Electronic Structures of Anchor Sites to Achieve Zero‐Valence Single‐Atom Catalysts for Advanced Hydrogenation
Authors: Li Yin , Xu Yuxing , Chen Si , Shi Xianxian , Gu Qingqing , Wang Leilei , Gu Minghui , Teng Botao , Yang Bing , Lu Junling
Published: May 2024

Single‐atom catalysts (SACs) have recently become highly attractive for selective hydrogenation reactions owing to their remarkably high selectivity. However, compared to their nanoparticle counterparts, atomically dispersed metal atoms in SACs often show inferior activity and are prone to aggregate under reaction conditions. Here, by theoretical calculations, we show that tuning the local electronic structures of metal anchor sites on g‐C3N4 by doping B atoms (BCN) with relatively lower electronegativity allows achieving zero‐valence Pd SACs with reinforced metal‐support orbital hybridizations for high stability and upshifted Pd 4d orbitals for high activity in H2 activation. The precise synthesis of Pd SACs on BCN supports with varied B contents substantiated the theoretical prediction. A zero‐valence Pd1/BCN SAC was achieved on a BCN support with a relatively low B content. It exhibited much higher stability in a H2 reducing environment, and more strikingly, a hydrogenation activity, approximately 10 and 34 times greater than those high‐valence Pd1/g‐C3N4 and Pd1/BCN with a high B content, respectively.
New Schiff bases and their vanadium complexes: Synthesis, characterization, and biological assessment for antibacterial and antiviral action
Authors: Khaldoune Khadija , Hasnaoui Ali , Rafya Meryem , Es‐sakhi Meriem , Benkhalti Fatiha , Hdoufane Ismail , Mague Joel T. , Neyts Johan , Jochmans Dirk , Cherqaoui Driss , el Firdoussi Larbi , Fdil Naima , Lazrek Hassan Bihi , Ait Ali Mustapha
Published: May 2024

From the perspective of possible antiviral and antibacterial activity of vanadium‐based complexes, we report the synthesis of new Schiff base ligand (L4) and a new Schiff‐base‐vanadium complex (C2). Both the ligand and the complex were characterized by Fourier transform infrared spectroscopy and Nuclear magnetic resonance techniques. Single‐crystal X‐ray Diffraction analysis has been used to confirm the structure of ligand L4 and complex C2. In addition, L1–4 and C1–3 were tested for their antibacterial effects against Escherichia coli and Staphylococcus aureus. Among the compounds, L2 demonstrated the most potent inhibition of both bacteria, exhibiting the lowest values for minimum inhibitory concentration (CMI) and minimum bactericidal concentration (CMB) (CMI = 0.16, CMB = 0.31 against E. coli, and CMI = CMB = 0.16 against S. aureus). Additionally, L2 produced the largest inhibition zones with diameters of 15.5 ± 0.15 against E. coli and 14.5 ± 0.04 against S. aureus. Furthermore, the antiviral efficacy of L1, L2, L4, C1, C2, and C3 against RNA viruses was assessed. C2 and C3 exhibited the most potent antiviral activity among the tested compounds.
Tailored BiPO4/Bi‐MOF heterostructure photocatalysts with diverse morphologies for highly efficient organic pollutant degradation
Authors: Liu Zhiwei , Wang Liying , Dong Shanghai , Li Lu , Wang Jingjing , Cao Zhenzhu , Zhang Yongfeng , Cheng Lin , Yang Jucai
Published: May 2024

Three distinct morphologies of Bi‐MOFs were innovatively employed as carriers, facilitating the formation of heterojunctions with BiPO4. Among these, the optimal photocatalytic performance was demonstrated by the type II heterojunction BiPO4/CAU‐17. Bi3+ competitively coordinated to crucially aid CAU‐17's transformation into a heterojunction, enhancing interfacial contact in BiPO4/CAU‐17. These photocatalysts effectively degraded dyes (RhB, MO, MB) and tetracycline (TC) under light exposure. RhB degradation was 3.33 times faster with BiPO4/CAU‐17 than BiPO4, 1.45 times faster than FCAU‐17, 1.36 times faster than FRCAU‐17, and 1.32 times faster than CAU‐17. Analyzing carrier density, Fermi level, and band structure through VB‐XPS, UV–VIS, and Mott–Schottky provided insights into enhanced separation of photoexcited electron–hole pairs. This study presents a novel approach to tackle the aggregation challenge of the wide‐bandgap material BiPO4 by using suitable MOFs as carriers. It offers valuable perspectives for the design and application of photocatalysts in environmental remediation.