bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal structure and variability of a shallow tropical reservoir
Authors: Xing Zikun , Fong Derek A. , Yat-Man Lo Edmond , Monismith Stephen G.
Published: December 2013

The structure and mixing dynamics of shallow tropical reservoirs was investigated using data collected in the Kranji Reservoir in Singapore. Water temperature data spanning a 2 month period in 2007 shows that diurnal cycles of stratification and destratification were formed in various locations in the reservoir. Temperature stratification of 0.5°C to 3.5°C was formed during the daylight hours and reduced nightly when cooling occurred. Substantial horizontal redistribution of heat was also observed between the side arms and the main body of the reservoir. The Kranji's dynamics can be summarized in terms of three physical forcing regimes: a solar radiation—dominated regime, a windy regime, and a cold inflow regime. We delineate the three physical forcing regimes by two potentially useful dimensionless numbers that quantify the relative influences of surface heating, wind stirring, and inflow buoyancy fluxes. For most of the measurement period (88% of the data record), the solar radiation—dominated regime characterized the hydrodynamics. In spite of the dominance of solar radiation in setting local stratification, it is shown that Kranji Reservoir is a three‐dimensional system in which there can be significant variations in temperature in the vertical and along‐reservoir directions, as determined by cold inflow events, differential heating, and reservoir releases. Moreover, the data suggest that the dynamical balance of the Kranji system is sensitive to small forcing events, with the timescales of stratification and mixing as short as a day or less.
The Great Salt Lake's monimolimnion and its importance for mercury bioaccumulation in brine shrimp (Artemia franciscana)
Authors: Jones Erin F. , Wurtsbaugh Wayne A.
Published: December 2013

The Great Salt Lake (Utah) is divided by a railroad causeway that causes the lake's south arm to be chemically stratified, when saltier, denser water from the north underflows into the south, creating an anoxic, sulfide‐rich deep brine layer that accumulates high levels of total mercury (Hg; 59 ng L−1) and methylmercury (33 ng L−1). Approximately 40% of this water is advected into the upper mixed layer annually. High mercury levels of brine shrimp (Artemia franciscana) in the mixed layer are passed to waterfowl, creating a human health hazard. We hypothesized that high mercury levels in Artemia are due to exposure when mercury is mixed into the upper layer or when they feed on mercury‐rich organic matter in the chemocline separating the two layers. Surprisingly, in aquaria growth experiments with 0%, 10%, or 25% deep brine water, Artemia exposed to progressively higher concentrations of mercury had significantly less mercury. In column experiments simulating a lake with a deep brine layer, Artemia grazed in the chemocline, but they also had lower mercury concentrations than Artemia in controls without a deep brine layer. This was due to detrital dilution of the mercury because the deep brine layer has very high particulate organic carbon (POC; 11.0 mg C L−1), which reduced the Hg : POC ratio of food 7‐fold compared to that in the overlying mixed layer. Consequently, although Artemia are exposed to the high concentrations of methylmercury generated in the deep layer, the detrimental effect is partially ameliorated by detrital dilution of the mercury.
Sea temperature shapes seasonal fluctuations in seaweed biomass within the Ningaloo coral reef ecosystem
Authors: Fulton Christopher J. , Depczynski Martial. , Holmes Thomas H. , Noble Mae M. , Radford Ben , Wernberg Thomas , Wilson Shaun K.
Published: December 2013

Environmental drivers of seaweed biomass were investigated at Ningaloo, Western Australia, a coral reef ecosystem with negligible anthropogenic influences on seaweeds from fishing, farming, or eutrophication. Periodic surveys of benthic macroalgae occupying seaweed‐dominated beds within the lagoon at two locations (Coral Bay, Tantabiddi) were made during winter, spring, and late summer over a 26 month period. Canopy‐forming Sargassum spp. biomass fluctuated over a seasonal growth—decay cycle, with highest values in the warm summer months (up to 1013 g fresh weight 0.25 m−2 at Coral Bay) and lowest values in winter (down to 155 g fresh weight 0.25 m−2 at Tantabiddi). Conversely, prominent understory seaweed genera Dictyopteris and Lobophora reached peak biomass in winter, when the Sargassum spp. canopy was lowest. Sargassum spp. biomass variation could be attributed largely to time (52%), location (21%), and site (26%), with low variation within individual seaweed beds (1%). Statistical analysis of the influence of five environmental variables (temperature, light, wind‐driven upwelling, rainfall, significant wave height) indicated that location and sea temperature (1 month antecedent to biomass) provided the best explanation for Sargassum spp. biomass fluctuations. While sea temperature is a key driver of seaweed temporal dynamics, heterogeneity at the kilometer scale suggests that spatial context is also important. Given the important role of seaweeds in many ecosystem processes, this strong biophysical coupling between Sargassum spp. biomass and sea temperature suggests that thermal climate change will significantly affect coral reef productivity and biodiversity.
Quantifying lake allochthonous organic carbon budgets using a simple equilibrium model
Authors: Hanson Paul C. , Buffam Ishi , Rusak James A. , Stanley Emily H. , Watras Carl
Published: December 2013

We quantify the allochthonous organic carbon (OC) budgets for seven north temperate lakes, using diverse information about their land cover, hydrology, and limnological characteristics. We develop a simple equilibrium model within a Bayesian framework that exploits the differences among the lakes to estimate three key rates: aerial loading (AOC) and wetland loading (WOC) from adjacent ecosystems and whole‐lake mineralization of OC (RDOC). Combined with observational data, these rates allow for estimates of the total OC loads, mineralization, and sedimentation within lakes and export to downstream ecosystems. AOC was 1.15 g C m−1 (shoreline) d−1, WOC ranged from 0.72 to 3.00 g C m−1 (shoreline) d−1, and RDOC, normalized to 20°C, ranged from 0.00083 to 0.0015 d−1. Total loads ranged from about 5 to 55 g C m−2 yr−1. Ecosystems immediately adjacent to lakes accounted for one‐half or more of total OC loads for some lakes. Whether a lake processed and stored more allochthonous OC than it exported depended primarily on hydrologic residence time. Our equilibrium model provides a parsimonious approach to quantifying allochthonous OC budgets in lakes with relatively minimal baseline data.
Inteligência Organizacional: conceitos, modelos e metodologias
Authors: Haber-Veja Adela , Más-Basnuevo Anays
Published: December 2013

Faz-se uma análise dos conceitos, modelos e metodologias da Inteligência a partir da perspectiva organizacional, com ênfase na Inteligência Organizacional (IO). As principais semelhanças e diferenças são visualizadas, com base na análise das principais definições da perspectiva organizacional da inteligência. Os modelos consultados para o desenvolvimento da IO são caracterizados, com base na pesquisa e aplicação na prática para sua introdução e desenvolvimento; e algumas limitações das metodologias expostas estão relacionadas, com base em uma breve análise das mesmas.
Modeling of HCHO and CHOCHO at a semi-rural site in southern China during the PRIDE-PRD2006 campaign
Authors: Li X. , Rohrer F. , Brauers T. , Hofzumahaus A. , Lu K. , Shao M. , Zhang Y. H. , Wahner A.
Published: December 2013

Abstract. HCHO and CHOCHO are important trace gases in the atmosphere, serving as tracers of VOCs oxidations. In the past decade, high concentrations of HCHO and CHOCHO have been observed for the Pearl River Delta (PRD) region in southern China. In this study, we performed box model simulations of HCHO and CHOCHO at a semi-rural site in PRD, focusing on understanding their sources and sinks and factors influencing the CHOCHO to HCHO ratio (RGF). The model was constrained by the simultaneous measurements of trace gases and radicals. Isoprene oxidation by OH radicals is the major pathway forming HCHO, followed by degradations of alkenes, aromatics, and alkanes. The production of CHOCHO is dominated by isoprene and aromatic degradation; contributions from other NMHCs are of minor importance. The modeled RGF shows a complex dependence on the VOCs composition, OH and NOx levels, and atmospheric physical processes, which suggest the necessity of careful treatment of RGF as an indicator of anthropogenic or biogenic emissions. Compared to the measurement results, the model predicts significant higher HCHO and CHOCHO concentrations. Sensitivity studies suggest that this discrepancy is to a large extent (>70%) due to the missing consideration of fresh emissions, vertical transport of precursor VOCs, and uptake of HCHO and CHOCHO by aerosols in the model. Insufficient treatments of dry deposition of HCHO and CHOCHO and of vertical dilution of all species in the model account for the rest 30% discrepancy. Our study indicates that, in addition to chemical mechanisms, atmospheric physical processes (e.g., transport, dilution, deposition) have to be well considered for a box model predicting HCHO and CHOCHO concentrations.
Impacts of a weather event on shelf circulation and CO2 and O2 dynamics on the Louisiana shelf during summer 2009
Authors: Huang W.-J. , Cai W.-J. , Wang Y. , Hopkinson C. S.
Published: December 2013

Abstract. While much is known about the physics of coastal currents, much less is known about the biogeochemical effects of surface currents on shelf carbon dioxide (CO2) and oxygen distribution and dynamics. The Mississippi and Atchafalaya River plume is usually observed along the Louisiana shelf with easterly winds. Such a typical pattern was observed in August 2007, i.e. a plume of low salinity and low partial pressure of CO2 (pCO2), indicating high biological production on the inner shelf; and higher salinity and pCO2 on the outer shelf. This high biological production induced by riverine nitrogen flux thus provided major organic matter sources for the shelf-wide hypoxia (dissolved oxygen [DO] < 2 mg L−1) accompanied by high dissolved inorganic carbon (DIC) concentrations in the bottom water. The slope of the DO and DIC relationship also demonstrated Redfield-type respiration in this shelf-wide hypoxia. In contrast, summer 2009 was an abnormal season characterized by a cool temperature in the central North America. Our observation and satellite chlorophyll a patterns both displayed a greatly distinct situation, i.e., the river plume was relocated to the eastern part of the Louisiana shelf; and high salinity and high pCO2 values occurred in surface waters of the western inner shelf. This plume relocation shifted the Louisiana shelf from a normally weak CO2 sink (as in 2007) to a strong CO2 source for the atmosphere. Although riverine nitrogen flux was enough to support a shelf-wide hypoxia in 2009, the plume relocation changed the location of high biological production and resulted in a limited hypoxic area. Furthermore, DIC concentration in bottom waters was higher than those predicted by the Redfield ratio, most likely because of much rapid O2 compensation than CO2 loss during air–sea exchange. Numerical models indicate such relocation of plume was mostly affected by the shelf circulation dominated by southerly and southwesterly winds. Consequently, we conclude that wind-forcing and shelf circulation are critical factors that influence the plume trajectories and the associated biogeochemical properties in coastal waters.
High-resolution hydraulic parameter maps for surface soils in tropical South America
Authors: Marthews T. R. , Quesada C. A. , Galbraith D. R. , Malhi Y. , Mullins C. E. , Hodnett M. G. , Dharssi I.
Published: December 2013

Abstract. Modern land surface model simulations capture soil profile water movement through the use of soil hydraulics sub-models, but good hydraulic parameterisations are often lacking, especially in the tropics. We present much-improved gridded datasets of hydraulic parameters for surface soil for the critical area of tropical South America, describing soil profile water movement across the region to 30 cm depth. Optimal hydraulic parameter values are given for the Brooks and Corey, Campbell, van Genuchten–Mualem and van Genuchten–Burdine soil hydraulic models, which are widely-used hydraulic sub-models in Land Surface Models. This has been possible through interpolating soil measurements from several sources through the SOTERLAC soil and terrain database and using the most recent pedotransfer functions (PTFs) derived for South American soils. All soil parameter data layers are provided at 15 arcsec resolution and available for download, this being 20 × higher resolution than the best comparable parameter maps available to date. Specific examples are given of the use of PTFs and the importance highlighted of using PTFs that have been locally-parameterised and that are not just based on soil texture. Details are provided specifically on how to assemble the ancillary data files required for grid-based vegetation simulation using the Joint UK Land Environment Simulator (JULES). We discuss current developments in soil hydraulic modelling and how high-resolution parameter maps such as these can improve the simulation of vegetation development and productivity in land surface models.
Constraining GRACE-derived cryosphere-attributed signal to irregularly shaped ice-covered areas
Authors: Colgan W. , Luthcke S. , Abdalati W. , Citterio M.
Published: December 2013

Abstract. We use a Monte Carlo approach to invert a spherical harmonic representation of cryosphere-attributed mass change in order to infer the most likely underlying mass changes within irregularly shaped ice-covered areas at nominal 26 km resolution. By inverting a spherical harmonic representation through the incorporation of additional fractional ice coverage information, this approach seeks to eliminate signal leakage between non-ice-covered and ice-covered areas. The spherical harmonic representation suggests a Greenland mass loss of 251 ± 25 Gt a−1 over the December 2003 to December 2010 period. The inversion suggests 218 ± 20 Gt a−1 was due to the ice sheet proper, and 34 ± 5 Gt a−1 (or ~14%) was due to Greenland peripheral glaciers and ice caps (GrPGICs). This mass loss from GrPGICs exceeds that inferred from all ice masses on both Ellesmere and Devon islands combined. This partition therefore highlights that GRACE-derived "Greenland" mass loss cannot be taken as synonymous with "Greenland ice sheet" mass loss when making comparisons with estimates of ice sheet mass balance derived from techniques that sample only the ice sheet proper.
Robust Stochastic Stability of Discrete-Time Markovian Jump Neural Networks with Leakage Delay
Authors: Kalidass Mathiyalagan , Su Hongye , Rathinasamy Sakthivel
Published: December 2013

This paper presents a robust analysis approach to stochastic stability of the uncertain Markovian jumping discrete-time neural networks (MJDNNs) with time delay in the leakage term. By choosing an appropriate Lyapunov functional and using free weighting matrix technique, a set of delay dependent stability criteria are derived. The stability results are delay dependent, which depend on not only the upper bounds of time delays but also their lower bounds. The obtained stability criteria are established in terms of linear matrix inequalities (LMIs) which can be effectively solved by some standard numerical packages. Finally, some illustrative numerical examples with simulation results are provided to demonstrate applicability of the obtained results. It is shown that even if there is no leakage delay, the obtained results are less restrictive than in some recent works.
Kaluza–Klein Cosmological Model, Strange Quark Matter, and Time-Varying Lambda
Authors: Jain Namrata , Bhoga Shyamsunder S. , Khadekar Gowardhan S.
Published: December 2013

In this paper, exact solutions of the Einstein field equations of the Kaluza-Klein cosmological model have been obtained in the presence of strange quark matter. We have considered the timevarying cosmological constant Λ as Λ = αH2 + βR-2, where α and β are free parameters. The solutions are obtained with the help of the equation of state for strange quark matter as per the Bag model, i.e. quark pressure p = 1/3(ρ - 4BC), where BC is Bag’s constant. We also discussed the physical implications of the solutions obtained for the model for different types of universes.
Identification of medicinal plant Schisandra chinensis using a potential DNA barcode ITS2
Authors: Li Xian-kuan , Wang Bing , Han Rong-chun , Zheng Yan-chao , Yin Hai-bo Yin , Xu Liang , Zhang Jian-kui , Xu Bao-li
Published: December 2013

To test whether the internal transcribed spacer 2 (ITS2) region is an effective marker for using in authenticating of the Schisandra chinensis at the species and population levels, separately. And the results showed that the wild populations had higher percentage of individuals that had substitution of C→A at site 86-bp than the cultivated populations. At sites 10-bp, 37-bp, 42-bp and 235-bp, these bases of the Schisandra sphenanthera samples differed from that of S. chinensis. Two species showed higher levels of inter-specific divergence than intra-specific divergence within ITS2 sequences. However, 24 populations did not demonstrate much difference as inter-specific and intra-specific divergences were concerned. Both S. chinensis and S. sphenanthera showed monophyly at species level, yet the samples of different populations shown polyphyly at population level. ITS2 performed well when using BLAST1 method. ITS2 obtained 100% identification success rates at the species level for S. chinensis, with no ambiguous identification at the genus level for ITS2 alone. The ITS2 region could be used to identify S. chinensis and S. sphenanthera in the “Chinese Pharmacopoeia”. And it could also correctly distinguish 100% of species and 100% of genera from the 193 sequences of S. chinensis. Hence, the ITS2 is a powerful and efficient tool for species identification of S. chinensis.
Noninvasive Visualization of the Atrioventricular Conduction System Using Cardiac Computed Tomography
Authors: Khoshknab Mirmilad , Zghaib Tarek , Xu Lingyu , Markman Timothy , Mavroudis Constantine , Desjardins Benoit , Nazarian Saman
Published: July 2024

Importance

Noninvasive localization of the compact atrioventricular node and the proximal specialized conduction system (AVCS) would enhance planning for transcatheter aortic valve and complex or congenital heart disease surgical procedures.

Objective

To test the hypothesis that preprocedure contrast-enhanced cardiac computed tomography (CECT) can accurately localize the AVCS by identification of the fat that insulates the conductive myocardium.

Design, Setting, and Participants

This was a prospective cohort study that took place at an academic tertiary care center. Included in the study were patients with CECT acquired less than 1 month before atrial fibrillation ablation and electroanatomic localization of the His electrogram signal on electroanatomic mapping (EAM) between January 2022 and January 2023.

Exposures

Preprocedure CECT.

Main Outcomes and Measures

The distance from the His electrogram signal to the fat segmentation encompassing the AVCS on CECT, after registration of the images to EAM.

Results

Among 20 patients (mean [SD] age, 66 [10] years; 15 male [75%]) in the cohort, the mean (SD) attenuation of the AVCS fat segmentation was 2.9 (21.5) Hounsfield units. The mean (SD) distance from the His electrogram to the closest AVCS fat voxel was 3.3 (1.6) mm.

Conclusions and Relevance

Results of this cohort study suggest that CECT could accurately localize the fatty tissue that insulates the AVCS from surrounding atrial and ventricular myocardium and may enhance the efficacy and safety of procedures targeting the conduction system and structures in its proximity.
Contribution of Clinical Trial Event Data by Data Source
Authors: Rymer Jennifer A. , Mulder Hillary , Wruck Lisa M. , Muñoz Daniel , Kripalani Sunil , Effron Mark B. , Gupta Kamal , Handberg Eileen , Jain Sandeep , Girotra Saket , Whittle Jeffrey , Hess Rachel , Benziger Catherine P. , Knowlton Kirk U. , Curtis Lesley H. , Roe Matthew T. , Hammill Bradley G. , Rothman Russell L. , Harrington Robert , Hernandez Adrian , Jones W. Schuyler
Published: July 2024

Importance

Pragmatic randomized clinical trials (RCTs) often use multiple data sources to examine clinical events, but the relative contribution of data sources to clinical end-point rates is understudied.

Objective

To assess the contribution of data sources (electronic health records [EHRs], public/private insurance claims, and/or participant-reported data) to clinical end points among ADAPTABLE participants who had available data.

Design, Setting, and Participants

The ADAPTABLE study was an open-label, pragmatic RCT from April 2016 through June 2019 conducted in research networks within clinical practice. Participants had existing atherosclerotic cardiovascular disease and available data to analyze. The characteristics of patients by combinations of data source availability were compared to examine the contribution of each of the data sources to end-point ascertainment. Data for this prespecified analysis were examined from January 2022 to June 2023.

Exposures

Randomized exposure to 81 mg or 325 mg of aspirin daily.

Main Outcomes and Measures

Number of events for the primary end point (composite of death, hospitalization for myocardial infarction, and hospitalization for stroke) that were contributed by EHR or claims data and then number of events contributed by each additional data source.

Results

Of 15 006 participants randomized with at least 1 other source of data available beyond participant-reported data, there were 8756 (58.3%) with participant-reported and EHR data; 4291 (28.6%) with participant-reported, EHR, and claims data; 1412 (9.4%) with EHR-only data; 262 (1.7%) with participant-reported and claims data; 202 (1.3%) with EHR and claims data; and 83 (0.6%) with claims-only data. Participants with EHR-only data were younger (median age, 63.7 years; IQR, 55.8-71.4) compared with the other groups (range, 65.6-71.9 years). Among participants with both EHR and claims data, with or without participant-reported data (n = 4493), for each outcome, most events (92%-100%) were identified in the EHR or in claims data. For all clinical end points, participant-reported data contributed less than 10% of events not otherwise available from claims or EHR data.

Conclusions and Relevance

In this analysis of a pragmatic RCT, claims and EHR data provided the most clinical end-point data when compared with participant-reported events. These findings provide a framework for collecting end points in pragmatic clinical trials. Further work is needed to understand the data source combinations that most effectively provide clinical end-point data in RCTs.
Social Isolation Changes and Long-Term Outcomes Among Older Adults
Authors: Lyu Chen , Siu Katherine , Xu Ian , Osman Iman , Zhong Judy
Published: July 2024

Importance

While the association between cross-sectional measures of social isolation and adverse health outcomes is well established, less is known about the association between changes in social isolation and health outcomes.

Objective

To assess changes of social isolation and mortality, physical function, cognitive function, cardiovascular disease (CVD), and stroke.

Design, Setting, and Participants

In a cohort design, social isolation changes in 4 years and subsequent risk of mortality and other outcomes were assessed using the 13 649 eligible Health and Retirement Study (HRS) respondents from the 2006 to 2020 waves. Data were analyzed from October 11, 2023, to April 26, 2024.

Exposure

The main exposure was the change in social isolation measured by the Steptoe 5-item Social Isolation Index from the initial assessment to a second assessment conducted 4 years later. Participants were classified into decreased isolation, stable, or increased isolation groups, stratified by their baseline isolation status.

Main Outcomes and Measures

The primary outcomes were mortality, self-reported dependencies in activities of daily living, Alzheimer disease and Alzheimer disease–related dementia, CVD, and stroke. Dementia, CVD, and stroke were assessed using HRS-linked Medicare records. Incidence rates (IRs) of each group were estimated and a Cox proportional hazards regression model was used, with inverse-probability treatment weighting to adjust for confounders.

Results

Among 13 649 participants (mean [SD] age at baseline, 65.3 [9.5] years; 8011 [58.7%] women) isolated at baseline, those with increased isolation had higher mortality (n = 693; IR = 68.19; 95% CI, 60.89-76.36 per 1000 person-years) than those who were stable (n = 1796; IR = 44.02; 95% CI, 40.47-47.88 person-years) or had decreased isolation (n = 2067; IR = 37.77; 95% CI, 34.73-41.09 person-years) isolation. Increased isolation was associated with higher risks of mortality (adjusted hazard ratio [AHR], 1.29; 95% CI, 1.09-1.51), disability (AHR, 1.35; 95% CI, 1.09-1.67), and dementia (AHR, 1.40; 95% CI, 1.02-1.93) compared with stable isolation. Similar findings were observed among socially nonisolated participants at baseline.

Conclusions and Relevance

In this cohort study, increased isolation was associated with elevated risks of mortality, disability, and dementia, irrespective of baseline isolation status. These results underscore the importance of interventions targeting the prevention of increased isolation among older adults to mitigate its adverse effects on mortality, as well as physical and cognitive function decline.
A Bioinspired Photosensitizer Performs Tumor Thermoresistance Reversion to Optimize the Atraumatic Mild‐Hyperthermia Photothermal Therapy for Breast Cancer
Authors: Li Jie , Yang Die , Lyu Wentao , Yuan Yan , Han Xiao , Yue Weiqing , Jiang Jian , Xiao Yingping , Fang Zhijie , Lu Xiaomei , Wang Wen , Huang Wei
Published: July 2024

Mild‐hyperthermia photothermal therapy (mPTT) has therapeutic potential with minimized damage to normal tissues. However, the poorly vascularized tumor area severely hampers the penetration of photothermal agents (PTAs), resulting in their heterogeneous distribution and the subsequent heterogeneous local temperature during mPTT. The presence of regions below the therapeutic 42 °C threshold can lead to incomplete tumor ablation and potential recurrence. Additionally, tumor anti‐apoptosis and cytoprotection pathways, particularly activated thermoresistance, can nullify mild hyperthermia‐induced tumor damage. Therefore, a bioinspired photosensitizer decorated with leucine to form biomimetic nanoclusters (CP‐PLeu nanoparticles (NPs)) aimed at achieving rapid and homogeneous accumulation in tumors, is introduced. Moreover, CP‐PLeu exhibits photodynamic effects that reverse tumor thermoresistance and physiological repair mechanisms, thereby inhibiting tumor resistance to hyperthermia. With the addition of NIR‐II laser irradiation, CP‐PLeu optimizes the therapeutic efficacy of mPTT and contributes to a minimally invasive therapeutic process for breast cancer. This therapeutic strategy, utilizing a biomimetic photosensitizer for homogeneous distribution of therapeutic temperature and photoactivated reversal of tumor thermoresistance, successfully achieves efficient breast tumor inhibition through an atraumatic mPTT process.
Nonenzymatic H2O2 Sensor Based on an Antibacterial Hierarchical Polypyrrole Nanopillar/Silver Nanoparticle Array
Authors: Shang Xue , Chen Panpan , Ling Wei , Hang Tian
Published: July 2024

A novel synthesis strategy for hierarchical polypyrrole nanopillar/silver nanoparticle arrays is designed and its application as an antibacterial surface and nonenzymatic H2O2 sensor is explored. The hierarchical structure is fabricated using a microporous membrane‐templated method by multiple steps. Using a polypyrrole nanopillar array as the matrix, silver nanoparticles can be uniformly reduced and stably anchored onto the nanopillar array by a redox reaction in a AgNO3 solution. The morphology, structural characteristics, conductivity, and reaction mechanisms of the composites are studied in detail. The incorporation of Ag nanoparticles not only significantly enhanced the antibacterial activity of the surface, but also contributed to the excellent ability to detect H2O2. This work provides a versatile approach to achieve the controlled fabrication of hierarchical metal‐conducting polymer composite structures and demonstrates them as promising multifunctional interfaces with antibacterial and sensing activity.
CoFe2O4@N‐CNH as Bifunctional Hybrid Catalysts for Rechargeable Zinc‐Air Batteries
Authors: Yadav Sudheer Kumar , Deckenbach Daniel , Yadav Sandeep , Njel Christian , Trouillet Vanessa , Schneider Jörg J.
Published: July 2024

Improving the efficiency of bifunctional electrocatalysts is a decisive challenge in the area of long‐lasting rechargeable zinc‐air batteries. Enhancing the catalysts' performance is crucial for advancing zinc‐air batteries. Transition‐metal oxides have emerged as promising non‐precious, noble‐metal‐free catalysts. Herein, a unique precursor directed approach is introduced for preparing a cobalt ferrite@nitrogen doped carbon nanohorns (CoFe2O4@N‐CNHs) nanohybrid catalyst in a single step annealing process involving stoichiometric amounts of single‐source cobalt and iron molecular precursors and carbon nanohorns (CNHs) under an argon/ammonia (Ar/NH3) atmosphere. This procedure enables a simultaneous CoFe2O4 ferrite synthesis and nitrogen functionalization of CNHs. The precious metal free nanohybrid CoFe2O4@N‐CNHs‐30% containing 30% of carbon presents an oxygen reduction reaction (ORR) half wave potential and onset potential comparable to the standard ORR catalyst 20% Pt/C. CoFe2O4@N‐CNHs‐30% also establishes superior oxygen evolution reaction (OER) performance with a low overpotential and a small Tafel slope than benchmark OER catalyst RuO2. Furthermore, the rechargeable zinc‐air battery with the CoFe2O4@N‐CNHs‐30% nanohybrid as air electrode demonstrates steadier and more durable charge–discharge cycles, and outstanding energy density relative to the state‐of‐the‐art 20% Pt/C‐RuO2 catalyst.
A Fundamental Correlative Spectroscopic Study on Li1‐xNiO2 and NaNiO2
Authors: Jacquet Quentin , Mozhzhukhina Nataliia , Gillespie Peter N.O. , Wittmann Gilles , Ramirez Lucia Perez , Capone Federico G. , Rueff Jean‐Pascal , Belin Stephanie , Dedryvère Rémi , Stievano Lorenzo , Matic Aleksandar , Suard Emmanuelle , Brookes Nicholas B. , Longo Alessandro , Prezzi Deborah , Lyonnard Sandrine , Iadecola Antonella
Published: July 2024

The intricate relationship between local atomic arrangements and electronic states significantly influences the electrochemical properties of Li‐ion battery cathode materials. Despite decades of investigation, a consensus regarding the local atomic and electronic structure of LiNiO2 remains elusive. This ambiguity stems from the potential distortion of Ni sites, either via Jahn‐Teller (JT) distortion or bond disproportionation (BD), complicating the understanding of the charge compensation mechanism involving Ni and O. This study compares the structures of LiNiO2 and NaNiO2, a JT system, using an innovative approach that integrates bulk spectroscopy techniques on standardized interoperable samples for enhanced reliability. While X‐ray absorption spectroscopy and theoretical calculations fail to differentiate between the proposed scenarios, Raman spectroscopy highlights local structural distinctions between monoclinic NaNiO2 and rhombohedral LiNiO2. HAXPES confirms various formal oxidation states for Ni, supported by RIXS data indicating 3d8 states, emphasizing negative charge transfer from Ni and some bond disproportionation in LiNiO2. Regarding charge compensation, XRS and RIXS suggest oxygen hole involvement in redox activity, whereas Raman spectroscopy does not detect molecular oxygen. This comprehensive spectroscopic analysis highlights the importance of correlative characterization workflows in elucidating complex structural‐electrochemical relationships.
Irrigated corn yield and soil phosphorus response to long‐term phosphorus fertilization
Authors: Balboa Guillermo Raul , Ferguson Richard , Puntel Laila
Published: July 2024

Long‐term experiments can help to understand soil phosphorus (P) dynamics and improve nutrient management strategies. This research evaluated long‐term (2002–2021) soil P dynamics and yield response to a range of P fertilizer rates in a continuous high‐yielding irrigated corn (Zea mays L.) experiment with low initial soil phosphorus test (SPT, 10.5 mg kg−1). The experiment was established near Clay Center, NE, and five P rates (0, 10, 20, 39, and 59 kg P ha−1) were evaluated. Soil samples at 20‐cm depth were collected in eight cropping seasons. Yield response to P fertilizer increased after 20 years from 0.64 to 2.79 Mg ha−1. The application of 39 kg P ha−1 year−1 increased soil Bray‐1 P to 19.5 mg kg−1, outyielded all other P treatments, and resulted in a positive relative P balance. Over 20 years, 0 kg P ha−1 year−1 decreased Bray‐1 P from 10.5 to 5.5 mg kg−1. Annual P rates of 0, 10, and 20 kg P ha−1 produced a negative relative P balance and SPT below the critical soil test value (CSTV). The CSTV was 22.2 mg kg−1 for a continuous irrigated corn cropping system. A 53% increase in the P fertilizer rate (from 39 to 59 kg P ha−1 year−1) produced a threefold increment in the soil test P build‐up rate. High‐yielding irrigated continuous corn production systems (>14 Mg ha−1) are required to apply at least 39 kg P ha−1 year−1 to maintain SPT and a positive relative P balance over years.
The steatosis‐associated fibrosis estimator score is a useful indicator of recurrence and survival after initial curative hepatectomy for hepatocellular carcinoma
Authors: Bekki Tomoaki , Ohira Masahiro , Imaoka Yuki , Hattori Minoru , Nakano Ryosuke , Sakai Hiroshi , Kuroda Shintaro , Tahara Hiroyuki , Ide Kentaro , Kobayashi Tsuyoshi , Ohdan Hideki
Published: July 2024

Aims

Liver fibrosis predisposes patients to liver failure and hepatocellular carcinoma. Various markers, which can be calculated easily from serum parameters, have been reported to predict liver fibrosis accurately. This study investigated the prognostic factors, including blood‐based markers for liver fibrosis of patients with hepatocellular carcinoma following initial curative hepatectomy.

Methods

This retrospective study included 407 patients with hepatocellular carcinoma who underwent initial curative hepatectomy between April 2010 and December 2017. We investigated prognosis‐associated variables in these patients.

Results

Among the blood‐based markers for liver fibrosis examined in this study, the steatosis‐associated fibrosis estimator score demonstrated the best predictive capabilities. This score was revealed as a poor prognostic factor for both overall survival and recurrence‐free survival in patients with hepatocellular carcinoma following initial curative hepatectomy. A high steatosis‐associated fibrosis estimator score was independently associated with poor overall survival and recurrence‐free survival. After propensity score‐matching to minimize bias between high‐ and low‐steatosis‐associated fibrosis estimator score groups, the high steatosis‐associated fibrosis estimator score remained associated with poor overall survival and recurrence‐free survival.

Conclusions

The steatosis‐associated fibrosis estimator score is an independent predictor of long‐term prognosis in patients with hepatocellular carcinoma following initial curative hepatectomy.
Towards a Sustainable Future: Challenges and Opportunities for Early‐Career Chemists
Authors: Dobbelaar Emiel , Goher Shaimaa S. , Vidal Juliana L. , Obhi Nimrat K. , Felisilda Bren M. B. , Choo Yvonne S. L. , Ismail Hossny , Lee Hooi Ling , Nascimento Vanessa , Al Bakain Ramia , Ranasinghe Muhandiramge , Davids Bianca L. , Naim Arish , Offiong Nnanake‐Abasi , Borges João , John Torsten
Published: July 2024

The concepts of sustainability and sustainable chemistry have attracted increasing attention in recent years, being of great importance to the younger generation. In this Viewpoint Article, we share how early‐career chemists can contribute to the sustainable transformation of their discipline. We identify ways in which they can engage to catalyse action for change. This article does not attempt to answer questions about the most promising or pressing areas driving research and chemical innovation in the context of sustainability. Instead, we want to inspire and engage early‐career chemists in pursuing sustainable actions by showcasing opportunities in education, outreach and policymaking, research culture and publishing, while highlighting existing challenges and the complexity of the topic. We want to empower early‐career chemists by providing resources and ideas for engagement for a sustainable future globally. While the article focuses on students and early‐career chemists, it provides insights to further stimulate the engagement of scientists from diverse backgrounds.
Chemical Constituents and Biological Activities of the Hylomecon japonica (Thunb.) Prantl & Kündig – A comprehensive Review
Authors: Wang Mengmeng , Shi Peixin , Zhang Min , Han Na
Published: July 2024

Hylomecon japonica (Thunb.) Prantl & Kündig (Papaveraceae) has a rich history of traditional medicinal uses, particularly in the treatment of bruises, rheumatism, and various ailments. Recent studies have identified alkaloids, saponins, terpenes, phenols, flavonoids, and other compounds in the plant, all of which demonstrate significant pharmacological effects such as anti‐inflammatory and anti‐tumor properties. While currently valued for its use in wetland plant landscapes and as a garden design color enhancer, ongoing research on the chemical composition and pharmacological properties of Hylomecon japonica is uncovering its potential medical applications. This paper provides a comprehensive review of extraction and separation methods, chemical components, and pharmacological activities of these compounds to further explore the medicinal potential of Hylomecon japonica.
Osteonecrosis of acetabulum following total hip arthroplasty: A case report and literature review
Authors: Zandi Reza , Talebi Shahin , Nodehi Saeed , Ehsani Akbar
Published: July 2024

Key Clinical Message

Despite being rare, we have presented a case of osteonecrosis of acetabulum that followed total hip arthroplasty. It's crucial to act appropriately, as it emulates periprosthetic joint infection. The key point is that the osteonecrosis of acetabulum may necessitate revision and can be classified as aseptic loosening.

Osteonecrosis of the femoral head is well known and managed with total hip arthroplasty (THA). Acetabulum osteonecrosis can be classified as a cause of painful THA and the cemented acetabular component is a feasible option. However, it seems that the osteonecrosis of acetabulum is sparsely alluded in literature. In this case report sustaining of the right hip pain following THA of 35‐year‐old woman is discussed.
Cryptococcal meningoencephalitis and pneumonia in a HIV positive patient: A case report
Authors: Mehdinezhad Hamed , Ghadir Sara , Maleh Parviz Amri , Akhondzadeh Ailin , Baziboroun Mana
Published: July 2024

Key Clinical Messages

Early diagnosis of cryptococcal infection is the key to improving outcomes, any newly diagnosed HIV patient presenting with subacute or chronic headache, particularly those who are CD4‐deplete, should be investigated for cryptococcal meningitis. We had some delay in our patient management, including delay in HIV diagnosis, delay in doing LP and delay in initiation of anti‐cryptococcal treatment and also early start of ART before specific cryptococcal treatment exacerbated IRIS in the patient. So, paying attention to these points can improve the prognosis of such patients.

Cryptocccus is a fungal pathogen and the causative agent of Cryptococcosis among human immunodeficiency virus (HIV) positive people. Meningoencephalitis is the most common manifestation of cryptococcal infection, while pulmonary cryptococcosis is often neglected due to nonspecific clinical and radiological presentation leading to a delay in diagnosis and disseminated disease. Here, we reported a 67‐year‐old man with newly diagnosed HIV who presented with concurrent cryptococcal meningoencephalitis and pulmonary cryptococcosis that admitted with the complaint of dyspnea and productive cough for 1.5 months, worsening shortness of breath, fever and weight loss since 15 days prior to admission. He also had severe oral candidiasis. Lung computed tomography (CT) revealed ill‐defined subpleural cavitary lesion in left lower zone with bilateral diffuse ground glass opacity and air bronchogram. His HIV PCR test was positive with absolute CD4 count less than 50 cells/mm3. After starting antiretroviral therapy (ART), he gradually developed a headache and decreased level of consciousness. Cerebrospinal fluid (CSF) analysis revealed 450 cells, predominantly lymphocytes, with protein of 343 mg/dL and glucose of 98 mg/dL (corresponding blood glucose 284 mg/dL). CSF India ink staining was positive for crypococcus spp. Liposomal amphotericin B in combination with fluconazole (due to the unavailability of flucytosin) was stated. He was intubated because of hypoxia and his bronchoalveolar lavage was positive for Cryptococcus spp. too. He died 2 weeks after starting antifungal therapy based on this study it should be mentioned that neurologic and respiratory symptoms may be the first presentation of acquired immunodeficiency syndrome.
Hypersensitivity reaction to rivaroxaban with a successful switch to apixaban: A case report
Authors: Mohammadi Keyhan , Ansari Ramin , Yaribash Shakila
Published: July 2024

Key Clinical Message

The precise management of hypersensitivity reactions to direct oral anticoagulants (DOACs) and the potential for cross‐reactivity among different DOACs remain unclear. In such cases, switching between DOACs may be feasible and could be considered, but close monitoring for adverse effects is essential, tailored to individual patient responses and tolerability.

Hypersensitivity reactions to DOACs, though considered rare, have been documented. This report describes the case of a 28‐year‐old male with a history of testicular cancer who was recently diagnosed with deep vein thrombosis. He was referred to an outpatient pharmacotherapy clinic due to suspected rivaroxaban‐induced cutaneous reactions. Following a thorough evaluation, his anticoagulant therapy was switched from rivaroxaban to apixaban. This change was successfully implemented, and no hypersensitivity symptoms recurred during subsequent follow‐up. This case demonstrates the importance of recognizing potential adverse reactions to DOACs and illustrates the feasibility of switching anticoagulants under close medical supervision to ensure patient safety and effective treatment.
Photoinduced Intermolecular Hydroamination and Hydroetherification of Electron‐Rich Alkenes With Low Catalyst Loadings
Authors: Jiang You‐Qin , Qu Pei , Wang Yong‐Hao , Liu Gong‐Qing
Published: July 2024

A photochemical method based on visible‐light irradiation (blue LEDs/sunlight) has been developed for the intermolecular hydroamination and hydroetherification of electron‐rich alkenes. This photochemical method is compatible with a wide range of azoles and electron‐rich alkenes, such as vinyl ethers, vinyl sulfides and enamides, and is performed with low concentrations of photocatalyst (1000 ppm). Comprehensive mechanistic studies indicate that this process is initiated by the formation of an active radical cation intermediate through single electron oxidation of azole, which is mediated by excited Acr‐Mes+ BF4−.
The crosstalk between N6‐methyladenosine readers and neuroblastoma
Authors: Chen Liping , He Jing , Zhuo Zhenjian
Published: July 2024

Background

Neuroblastoma (NB) is a heterogeneous pediatric solid tumour strongly influenced by epigenetic modifications.

Methods

This review explores the role of N6‐methyladenosine (m6A) modifications and their readers in NB progression.

Results

Dysregulation of m6A readers, including YTHDF1/2, YTHDC1, IGF2BP1/2/3, HNRNPA2B1 and HNRNPC, has been associated with susceptibility and progression.

Conclusion

Understanding the crosstalk between m6A readers and NB could offer new insights into diagnosis, prognosis, and treatment strategies.
Comparison of remimazolam and midazolam for sedation during colonoscopy in Japanese patients: A propensity score matching analysis
Authors: Ogura Kanako , Ichijima Ryoji , Ikehara Hisatomo , Sugita Tomomi , Yamaguchi Daisuke , Nagata Yasuhiko , Esaki Mitsuru , Minoda Yosuke , Ono Hiroyuki , Hotta Kinichi , Kiriyama Shinsuke , Sumiyoshi Tetsuya , Kanmura Yuichi
Published: July 2024

Objectives

To compare the efficacy and safety of sedation with midazolam and remimazolam for colorectal endoscopy.

Methods

This single‐center, two‐arm, post‐hoc analysis of the REM‐IICTJP01 study investigated the efficacy and safety of remimazolam for gastrointestinal endoscopic sedation. We enrolled 40 and 208 patients who underwent colonoscopy under remimazolam and midazolam sedation, respectively, during the same period. The primary outcome was the time from the end of the colonoscopy until discharge. The secondary outcomes included the time from the end of the colonoscopy until awakening, dosage, and adverse events. Propensity score matching was employed to eliminate the effect of confounding factors.

Results

Thirty‐seven patients in each group were matched. After propensity matching, the time to awakening after colonoscopy was 28.0 (13.0–37.0) min in the midazolam group and 0 (0–0) min in the remimazolam group; moreover, the time till discharge was 40.0 (35.0–46.5) min in the midazolam group and 0 (0–5.0) min in the remimazolam group, both of which were significantly shorter in the remimazolam group (p < 0.01). The number of additional doses was 0 (0–0) and 2 (1–3) in the midazolam and remimazolam groups, respectively. The total dose was 2.0 (2.0–3.5) and 6.0 (5.0–7.0) mg in the midazolam and remimazolam groups, respectively.

Conclusions

Remimazolam yielded significantly faster times to awakening and discharge safely compared to midazolam.
Estimation of maximum body size in fossil species: A case study using Tyrannosaurus rex
Authors: Mallon Jordan C. , Hone David W. E.
Published: July 2024

Among extant species, the ability to sample the extremes of body size—one of the most useful predictors of an individual's ecology—is highly unlikely. This improbability is further exaggerated when sampling the already incomplete fossil record. We quantify the likelihood of sampling the uppermost limits of body size in the fossil record using Tyrannosaurus rex Osborn, 1905 as a model, selected for its comparatively well‐understood life history parameters. We computationally generate a population of 140 million T. rex (based on prior estimates), modelling variation about the growth curve both with and without sexual dimorphism (the former modelled after Alligator mississippiensis), and building in sampling limitations related to species survivorship and taphonomic bias, derived from fossil data. The 99th percentile of body mass in T. rex has likely already been sampled, but it will probably be millennia before much larger giants (99.99th percentile) are sampled at present collecting rates. Biomechanical and ecological limitations notwithstanding, we estimate that the absolute largest T. rex may have been 70% more massive than the currently largest known specimen (~15,000 vs. ~8800 kg). Body size comparisons of fossil species should be based on ontogenetically controlled statistical parameters, rather than simply comparing the largest known individuals whose recovery is highly subject to sampling intensity.