bluuebunny/crossref_metadata_2025 huggingface dataset:
A multiisotope C and N modeling analysis of soil organic matter turnover and transport as a function of soil depth in a California annual grassland soil chronosequence
Authors: Baisden W. T. , Amundson R. , Brenner D. L. , Cook A. C. , Kendall C. , Harden J. W.
Published: December 2002

We examine soil organic matter (SOM) turnover and transport using C and N isotopes in soil profiles sampled circa 1949, 1978, and 1998 (a period spanning pulse thermonuclear 14C enrichment of the atmosphere) along a 3‐million‐year annual grassland soil chronosequence. Temporal differences in soil Δ14C profiles indicate that inputs of recently living organic matter (OM) occur primarily in the upper 20–30 cm but suggest that OM inputs can occur below the primary rooting zone. A three‐pool SOM model with downward transport captures most observed variation in Δ14C, percentages of C and N, δ13C, and δ15N, supporting the commonly accepted concept of three distinct SOM pools. The model suggests that the importance of the decadal SOM pool in N dynamics is greatest in young and old soils. Altered hydrology and possibly low pH and/or P dynamics in highly developed old soils cause changes in soil C and N turnover and transport of importance for soil biogeochemistry models.
Changes in population and agricultural land in conterminous United States counties, 1790 to 1997
Authors: Waisanen Pamela J. , Bliss Norman B.
Published: December 2002

We have developed a data set of changes in population and agricultural land for the conterminous United States at the county level, resulting in more spatial detail than in previously available compilations. The purpose was to provide data on the timing of land conversion as an input to dynamic models of the carbon cycle, although a wide variety of applications exist for the physical, biological, and social sciences. The spatial data represent the appropriate county boundaries for each census year between 1790 and 1997, and the census attributes are attached to the appropriate spatial region. The resulting time series and maps show the history of population (1790–1990) and the history of agricultural development (1850–1997). The patterns of agricultural development reflect the influences of climate, soil productivity, increases in population size, variations in the general economy, and technological changes in the energy, transportation, and agricultural sectors.
A possible global covariance between terrestrial gross primary production and13C discrimination: Consequences for the atmospheric13C budget and its response to ENSO
Authors: Randerson J. T. , Collatz G. J. , Fessenden J. E. , Munoz A. D. , Still C. J. , Berry J. A. , Fung I. Y. , Suits N. , Denning A. S.
Published: December 2002

It is well known that terrestrial photosynthesis and13C discrimination vary in response to a number of environmental and biological factors such as atmospheric humidity and genotypic differences in stomatal regulation. Small changes in the global balance between diffusive conductances to CO2and photosynthesis in C3 vegetation have the potential to influence the13C budget of the atmosphere because these changes scale with the relatively large one‐way gross primary production (GPP) flux. Over a period of days to years, this atmospheric isotopic forcing is damped by the return flux consisting mostly of respiration, Fire, and volatile organic carbon losses. Here we explore the magnitude of this class of isotopic disequilibria with an ecophysiological model (SiB2) and a double deconvolution inversion framework that includes time‐varying discrimination for the period of 1981–1994. If the net land carbon sink and plant13C discrimination covary on interannual timescales at the global scale, consistent with El Niño‐induced drought stress causing a decline in global GPP and C3 discrimination, then less interannual variability in ocean and land net carbon exchange is required to explain atmospheric trends in δ13C and CO2as compared with previous studies that assumed discrimination was invariant.
Large forest fires in Canada, 1959–1997
Authors: Stocks B. J. , Mason J. A. , Todd J. B. , Bosch E. M. , Wotton B. M. , Amiro B. D. , Flannigan M. D. , Hirsch K. G. , Logan K. A. , Martell D. L. , Skinner W. R.
Published: December 2002

A Large Fire Database (LFDB), which includes information on fire location, start date, final size, cause, and suppression action, has been developed for all fires larger than 200 ha in area for Canada for the 1959–1997 period. The LFDB represents only 3.1% of the total number of Canadian fires during this period, the remaining 96.9% of fires being suppressed while <200 ha in size, yet accounts for ∼97% of the total area burned, allowing a spatial and temporal analysis of recent Canadian landscape‐scale fire impacts. On average ∼2 million ha burned annually in these large fires, although more than 7 million ha burned in some years. Ecozones in the boreal and taiga regions experienced the greatest areas burned, with an average of 0.7% of the forested land burning annually. Lightning fires predominate in northern Canada, accounting for 80% of the total LFDB area burned. Large fires, although small in number, contribute substantially to area burned, most particularly in the boreal and taiga regions. The Canadian fire season runs from late April through August, with most of the area burned occurring in June and July due primarily to lightning fire activity in northern Canada. Close to 50% of the area burned in Canada is the result of fires that are not actioned due to their remote location, low values‐at‐risk, and efforts to accommodate the natural role of fire in these ecosystems. The LFDB is updated annually and is being expanded back in time to permit a more thorough analysis of long‐term trends in Canadian fire activity.
Fire history and postfire forest development in an upland watershed of interior Alaska
Authors: Fastie Christopher L. , Lloyd Andrea H. , Doak Patricia
Published: December 2002

We reconstructed the history of wildfire in the study area of the 1999 FROSTFIRE experimental fire in interior Alaska using information from fire‐scarred trees, fire‐killed trees, tree recruitment dates, tree radial growth increases, and aerial photographs. This combination of methods resulted in more temporal and spatial precision than would have been possible with any subset. Stand‐destroying wildfires affected 93% of the FROSTFIRE watershed and 47% of the control watershed between 1896 and 1925. We found no evidence for severe fires earlier in the 19th century or later in the 20th century, suggesting a temporal cluster of fires. The ignition of some of these fires may be associated with early 20th century mining activity near the study area. There is no evidence that any part of the study area has been burned by more than one severe fire in the past 200–250 years, suggesting fire frequencies lower than previously published estimates. Forests with prefire species composition developed within several decades following fire in birch forests and black spruce forests. South‐facing birch forests show no evidence of succeeding to white spruce forests 200 years after fire.
Microphysical modeling of the 1999–2000 Arctic winter 2. Chlorine activation and ozone depletion
Authors: Drdla K. , Schoeberl M. R.
Published: December 2002

The effect of polar stratospheric clouds (PSCs) on ozone depletion during the 1999–2000 Arctic winter has been assessed using a coupled microphysical/photochemical model. Scenarios spanned a large range of denitrification levels, with up to 80% vortex‐averaged denitrification and localized dehydration. PSC composition was varied, exploring sensitivity to heterogeneous reaction rates. PSC formation during February was critical in causing severe ozone depletion below 500 K. Heterogeneous chemistry on these PSCs was able to continuously reactivate the newly produced ClONO2. Only 30–40% vortex‐averaged ozone loss would have occurred without this chlorine reactivation; with it, 21–32% more ozone loss is possible. During February (unlike earlier in the winter), chlorine reactivation and ozone loss were sensitive to heterogeneous chemistry: varying the reactivities altered ozone loss by 11%. An analysis of the critical temperatures for heterogeneous chemistry demonstrates the importance of temperatures near the nitric acid trihydrate condensation point, where many uncertainties influence heterogeneous reaction rates. Chlorine reactivation during February also prevented denitrification from enhancing ozone loss until March: 70% vortex‐averaged denitrification only enhanced ozone depletion by 3% on 10 March. The mid‐March vortex breakup probably limited the extent of ozone depletion; if the vortex had remained stable until 15 April, 16% ozone loss (out of a total 68% ozone loss) could be caused by 70% denitrification. Ozone loss intensifies nonlinearly with enhanced denitrification: in individual air parcels with 90% denitrification, 40% ozone loss in mid‐April can be attributed to denitrification alone.
Characteristics of quasi‐monochromatic gravity waves observed with Na lidar in the mesopause region at Starfire Optical Range, NM
Authors: Hu Xiong , Liu Alan Z. , Gardner Chester S. , Swenson Gary R.
Published: December 2002

The University of Illinois Na wind/temperature lidar data collected at the Starfire Optical Range, NM, between Jan. 1998 and May 2000 was used to extract the dominant monochromatic gravity waves. By using simultaneously measured horizontal wind and temperature profiles, the vertical wavelengths (λz), (TI), and propagation directions were determined using the hodograph method. A total of 700 monochromatic gravity waves were analyzed from ∼300 h of observations. It was found that 84.4% of the waves were propagating upwards. The mean λz was 12.6 km and 9.9 km for upward and downward propagating waves, respectively, and showed a bimodal distribution with the largest number of waves at 15–17 km and 7–9 km. The mean TI is ∼10 h. There is no dominant direction of propagation. For waves with λz <11 km, the percentage of upward propagating waves is lower (71%).
Three‐dimensional modeling of blue jets and blue starters
Authors: Pasko Victor P. , George Jeremy J.
Published: December 2002

Blue jets and blue starters are considered as positive streamer coronas expanding from the streamer zones of conventional lightning leaders under conditions when large‐scale electric fields near the thundercloud tops exceed the minimum field required for the propagation of positive streamers in air. Results from a three‐dimensional fractal model based on a phenomenological probabilistic approach to the modeling of streamer coronas indicate, in particular, that blue jets and blue starters can be formed by a fast (∼1 s) accumulation of ∼110–150 C of positive thundercloud charge distributed in a volume with effective radius ∼3 km near the cloud top at ∼15 km. The model simulates the propagation of branching streamer channels constituting blue jets and blue starters as a three‐dimensional growth of fractal trees in the electric field created by thundercloud charges and self‐consistently accounts for the electric field effects due to the propagating streamers. Model results closely resemble blue jet and blue starter characteristics in terms of their altitude extents, transverse dimensions, and conical structure and indicate that blue starters are related to the initial phases of blue jets. The proposed model is supported by the recent spectroscopic observations of blue jets and blue starters, in particular, by the documentation of the 427.8 nm (first negative N2+) emission in blue starters as well as by the low‐pressure laboratory experiments on emission spectroscopy of corona streamers in air. The model results also appear to be in excellent agreement with the recent discovery of the streamer structure of blue jets.
Frequency‐dependent seismic attenuation in the inner core 2. A scattering and fabric interpretation
Authors: Cormier Vernon F. , Li Xu
Published: December 2002

Broadband velocity waveforms of PKIKP in the distance range 150–180° are inverted for a model of inner core attenuation due to forward scattering by a three‐dimensional heterogeneous fabric. A mean velocity perturbation of 8.4 ± 1.8% and a scale length of heterogeneity of 9.8 ± 2.4 km are determined from 262 available PKIKP ray paths. The velocity perturbations are larger for polar than for equatorial paths, decrease with depth, and show anisotropy in both global and regional data. For paths beneath North America, the smallest scale lengths (1–5 km) tend to lie in either the upper 200 km of the inner core or along paths close to the rotational axis. The depth dependence of attenuation is roughly similar to that obtained assuming a viscoelastic origin, except a more abrupt transition is seen between higher attenuation in the upper inner core and lower attenuation in the lower inner core. This transition may be sharp enough to produce either a first‐ or second‐order discontinuity with depth in the long‐wavelength (composite) elastic moduli. A fabric that satisfies the observed depth dependence and anisotropy of attenuation requires solidification of iron crystals having high (>10%) intrinsic anisotropy, which are preferentially aligned in time and depth. Since weak velocity dispersion, elastic anisotropy, attenuation anisotropy, and their depth dependence agree with that predicted by such a fabric, we suggest that scattering attenuation is not a small fraction but, rather, the predominant mechanism of attenuation in the inner core in the 0.02–2‐Hz frequency band.
Cumulative mixing inferred from stratospheric tracer relationships
Authors: Morgenstern Olaf , Lee Adrian M. , Pyle John A.
Published: December 2002

Stratospheric mixing is studied using a chemical transport model simulating the evolution of 12 long‐lived tracers at high resolution. A model integration is performed covering the period from March 1999 to August 2001. From the tracer relationships in the lower stratosphere we infer relative tracer lifetimes. Where the model captures the species' sinks properly and where the tracers are largely inert in the lower stratosphere, the model tracer lifetimes compare favorably with literature values. The breakup phases of the polar vortices in the two boreal winters covered by the simulation are studied in some detail. In both winters, before the final warming, separate canonical correlations appear. Mixing manifests itself in a progressive merger of the correlation curves marking the polar vortex and middle latitudes. We introduce a method to quantify the origins of fractions of simulated air masses based on tracer relationships describing the situation prior to the final warming. In both years, several weeks after the final vortex breakdown of the polar vortex, the method retrieves realistic quantities of former polar vortex air. The findings are verified using idealized tracer advection experiments. Some important differences between the two winters emerge with regard to the size and longevity of the polar vortex.
Impact of anthropogenic sources on carbonyl sulfide in Beijing City
Authors: Yujing Mu , Hai Wu , Zhang Xiaoshan , Jiang Guibin
Published: December 2002

The diurnal variations for carbonyl sulfide (COS) were measured during fall and winter seasons. All diurnal cycles except one day under strong wind showed characteristic diurnal variations for COS, with low values in daytime and high values at night. The vertical distribution of COS showed a significant gradient for COS among the three investigated heights; the mixing ratios of COS decreased while altitude increased. The high mixing ratios and distinct vertical distributions of COS indicate that strong sources of COS exist in Beijing City. Domestic stoves and central heaters are important sources of COS during winter season. Cesspools may play significant role on COS over whole seasons.
Atmospheric histories of halocarbons from analysis of Antarctic firn air: Major Montreal Protocol species
Authors: Sturrock G. A. , Etheridge D. M. , Trudinger C. M. , Fraser P. J. , Smith A. M.
Published: December 2002

Air samples extracted from Antarctic firn at Law Dome have been analyzed for the suite of halocarbons that contribute most of the anthropogenic chlorine and about half the anthropogenic bromine presently released into the stratosphere. The species, all included in the Montreal Protocol, are the chlorofluorocarbons (CFCs ‐11, ‐12, ‐113, ‐114, ‐115), hydrochlorofluorocarbons (HCFCs ‐22, ‐141b, ‐142b), halons (H ‐1211, ‐1301), CH3CCl3 (methyl chloroform) and CCl4 (carbon tetrachloride). The measurements were used to reconstruct the atmospheric history of these species since the 1930s, providing a record considerably predating existing in situ records or other conventional air archives, encompassing virtually the entire history of anthropogenic emissions of CFCs, HCFCs, and halons and giving early 20th century levels for CH3CCl3 and CCl4. Significant features of this study are (1) the narrow age spread (spectral width 5 years) of the individual firn air samples, which reveals rapid atmospheric changes, (2) the use of inversion techniques to infer past atmospheric composition with associated uncertainties, and (3) the low analytical detection limit (<0.1 ppt), which, together with the narrow air age spread, detects early background levels and resolves the time that industrial emissions first appeared in the southern hemisphere atmosphere. Integrity of the data is demonstrated by successful intercomparison of data from independent firn sites on Law Dome with common time‐series. An upper limit is given for the potential contribution to atmospheric levels of CH3CCl3 from nonindustrial sources. The atmospheric records produced from firn air are compared to calculations based on the history of their global emissions.
Promotion of Large Protein Crystal Growth with Stirring Solution
Authors: Adachi Hiroaki , Takano Kazufumi , Yoshimura Masashi , Mori Yusuke , Sasaki Takatomo
Published: December 2002

We propose a protein crystal growth with stirring the solution, which is entirely different approach compared with the conventional method. The novel method, which we call the Floating And Stirring Technique (FAST), enables both growing crystals on an insoluble and very dense liquid without contacting the vessel and stirring the protein solution mildly. Using this method together with slow cooling, we obtained a 3.0 mm-long lysozyme crystal in 20 days from a seed crystal. This is larger than the 2.0 mm-long crystal grown without stirring. Stirring the protein solution accelerates the growth of the protein crystal and prevents additional spontaneous nucleation.
Formation of p-Type Hg0.7Cd0.3Te Epilayers Grown on CdTe Buffer Layers on GaAs (211) B due to In Situ Thermal Annealing
Authors: Ryu Young Sun , Song Bong Seok , Kang Tae Won , Kim Hyun Jeong , Kim Tae Whan
Published: December 2002

Fourier transform infrared (FTIR) transmission and Hall effect measurements were performed to investigate the optical and electrical properties of as-grown and in situ-annealed Hg1-x
Cd
x
Te epilayers grown on CdTe buffer layers by molecular beam epitaxy. After annealing the Hg1-x
Cd
x
Te epliayers in a Hg cell flux atmosphere, the FTIR spectra showed that their transmission intensity increased in comparison to that of the as-grown Hg1-x
Cd
x
Te epilayer. Hall effect measurements showed that the carrier concentration decreased and the mobility increased after annealing. These results indicate that Hg atoms not only effectively passivate the Hg vacancies in the Hg1-x
Cd
x
Te epilayers but can also convert the as grown n-epilayers to p-Hg1-x
Cd
x
Te epilayers due to in situ thermal annealing.
Effect of Transparent Conductive Oxide Stability on CdS/CdTe Solar Cell Performance
Authors: Alamri Saleh N.
Published: December 2002

Thin film CdS/CdTe solar cells fabricated on SnO2:F-coated glass have been found to have higher efficiencies than similar cells produced on indium-tin oxide (ITO) and tin oxide layer on indium-tin oxide (ITO/SnO2)-coated glass substrate. The transmission measurements revealed that SnO2:F was the most stable transparent conductive oxide.
Field Dependence of Jc for Filamentary Eu123 Superconductors
Authors: Ban Eriko , Goto Tomoko , Watanabe Kazuo , Matsuoka Yoshiharu
Published: December 2002

The transport J
c for filamentary Eu123 superconductors prepared by a solution spinning method was examined at 77 K in magnetic fields up to 10 T. The samples which partially melted under flowing 0.1%O2+Ar and 1%O2+Ar had a well-aligned structure along the filament diameter as well as the length. Excellent behavior in the field dependence of J
c was detected for the filamentary Eu123 superconductors which partially melted in flowing 0.1%O2+Ar. Significant angular dependence along the diameter of the J
c value was not detected and a high J
c value of around 104 A/cm2 at 77 K and 10 T was maintained.
Noise Reduction Process with Generalized Harmonics Analysis for High-Temperature Superconducting Quantum Interference Device Magnetocardiography
Authors: Sakuta Ken , Ogawa Kaname , Tamai Hideaki , Mizukami Akifumi , Kobayashi Takeshi
Published: December 2002

Generalized harmonic analysis was applied to a high-temperature superconducting quantum interference device (SQUID) magnetocardiograph signal processing system. The noise frequencies in the signal waveform were calculated by the generalized harmonic analysis (GHA) and the noise components with these frequencies were subtracted from the acquired signal data. Two types of the subtraction procedure were demonstrated: one using the adaptive filtering algorithm and the other a simple subtraction. In both cases, the noise components were reduced. The former system performed rapid calculations but generated an artificial noise in the high-frequency region, because of rough GHA estimation, while in the latter case, the calculation was time-consuming but the noise estimation was carried out accurately, because of the precision of GHA procedure. In the present study, a distinctive noise component at 16 Hz was completely suppressed by the GHA prediction noise reduction process. The proposed systems were well suited for application to an unshielded high-temperature SQUID system.
A Low-temperature in situ Template Reduction-Carbonization Route to TiC Submicrometer Hollow Spheres and Nanorods
Authors: Tang Kaibin , Shen Guozhen , Chen Di , An Changhua , Wang Chunrui , Qian Yitai
Published: December 2002

TiC submicrometer hollow spheres and nanorods were successfully synthesized at relatively low temperature. The products were characterized by XRD, TEM, and ED procedures. A low-temperature in situ template reduction-carbonization mechanism was proposed.
Binuclear and Tetranuclear Copper(II) Complexes Bridged by Dimethylglyoxime
Authors: Chen Xiao-Yan , Cheng Peng , Liu Xuan-Wen , Yan Shi-Ping , Bu Wei-Ming , Liao Dai-Zheng , Jiang Zong-Hui
Published: December 2002

Two novel copper(II) complexes, [Cu4(tacn)2(Hdmg)2(dmg)2](ClO4)2 (1) and [Cu2(dmg)(Hdmg)(H2dmg)(H2O)]ClO4 (2), bridged by dimethylglyoxime have been synthesized and characterized by single crystal X-ray diffraction method.
Attachment anxiety and the dark triad increase stalking after breakups of romantic relationships through psychological maltreatment of romantic partners and reactions to breakups
Authors: Kanemasa Yuji , Miyagawa Yuki , Arai Takashi
Published: January 2024

This study examined whether two personality traits, attachment anxiety, and the Dark Triad, longitudinally promote stalking behaviors after romantic breakups through psychological maltreatment of partners during relationships and maladjusted reactions to breakups. We conducted a prospective longitudinal study across four waves of assessment for 1 year of individuals in romantic relationships in Japan. They completed measures of attachment anxiety, the Dark Triad, need for control, and psychological intimate partner violence (IPV) perpetration at Wave 1, and measures of maladjusted reactions to breakups (i.e., anger and rumination) and stalking behaviors at a wave after breakups. The final sample consisted of 356 participants who were involved in romantic relationships at Wave 1 and left by their partners during the survey period. Correlational analysis showed that the Dark Triad at Wave 1 was significantly positively associated with future stalking behaviors, but attachment anxiety was not. Structural equation modeling showed that attachment anxiety and the Dark Triad increased future stalking behaviors after breakups through psychological IPV perpetration during relationships. Additionally, attachment anxiety increased future stalking behaviors through higher levels of postbreakup anger and rumination. Conversely, we did not find any indirect effects of the Dark Triad on stalking behaviors through these reactions toward breakups. Overall, these results suggest that it is necessary to consider personality traits that could damage intimate relationships and to focus on the quality of romantic relationships to prevent stalking after romantic breakups. These results also indicate that emotion regulation may be useful in preventing stalking caused by attachment anxiety.
Real‐World Treatment and Care Patterns in Patients With Rheumatoid Arthritis Initiating First‐Line Tumor Necrosis Factor Inhibitor Therapy in the United States
Authors: Edgerton Colin , Frick Andrew , Helfgott Simon , Huston Kent Kwas , Singh Jasvinder A. , Zueger Patrick , Anyanwu Samuel I. , Patel Pankaj , Soloman Nehad
Published: January 2024

Objective

Treatment guidelines for rheumatoid arthritis (RA) recommend targeting low disease activity or remission and switching therapies for patients not reaching those targets. We evaluated real‐world use of disease activity measures, treatment discontinuation, and switching patterns among patients with RA initiating a first‐line tumor necrosis factor inhibitor (TNFi).

Methods

Data from adult patients with RA initiating a first‐line TNFi were collected from the American Rheumatology Network (January 2014–August 2021). The proportion of patients with recorded disease activity scores (Clinical Disease Activity Index [CDAI] or Routine Assessment of Patient Index Data 3 [RAPID3]) at TNFi initiation was assessed. Among patients with moderate or severe RA at TNFi initiation, reasons for discontinuation and subsequent advanced therapy were evaluated.

Results

Among TNFi initiators (n = 15,182), 44.8% recorded a CDAI/RAPID3 score at treatment initiation; of those who did not, 47.0% had recorded a tender and/or swollen joint count or pain score. Among patients with moderate or severe RA (n = 1,651), 52% discontinued their initial TNFi during follow‐up, of which 15%, 46%, 28%, and 12% initiated the same TNFi, another TNFi, a non‐TNFi biologic, or a Janus kinase inhibitor, respectively. The proportion of patients restarting the same TNFi or initiating another TNFi varied according to TNFi discontinuation reason.

Conclusion

In clinical practice, over half of patients with RA initiating a first‐line TNFi did not have baseline disease activity assessments. Many patients cycled through TNFi despite citing lack of efficacy as the most common reason for discontinuation. Consistent, objective monitoring of treatment response and timely switch to effective therapy is needed in patients with RA.
Adaptive consensus tracking control for robotic manipulators with nonlinear time‐varying fault‐tolerant actuator and unknown control input directions
Authors: Zhang Qianyi , Zhang Qingzhen , Liu Jinkun
Published: January 2024

The consensus tracking mechanism of a multi‐agent system consisting of third‐order nonlinear single joint manipulators was investigated in this study based on the pertinent industrial context. Unlike many previous studies on consensus control that presumed a known control direction, this investigation addressed the complex challenges posed by unknown control directions and time‐varying actuators. Specifically, we explored both time‐invariant and time‐varying actuator faults in scenarios wherein all parameters are unknown. The Nussbaum function was utilized to resolve time‐varying nonlinear fault‐tolerance and unknown control direction problems. In the design process of the control law, the backstepping method combining with Nussbaum function is adopted to address unmatched nonlinearity and unmatched uncertainty system, and the radial basis function neural network is used to approximate the unknown parameters The resulting control law allows all robotic manipulators to track the angle and angular velocity of the leader. Simulation results demonstrate the effectiveness of the proposed control scheme.
Effects of Hawthorn Flavonoids on Intestinal Microbial Community and Metabolic Phenotype in Obese Rats
Authors: Bi Yu , Lv Chang , Zhu Juanjuan , Zhou Qiao , Xu Xiaoxiao , Yang Shuo , Shi Dianhua , Zhou Qian , Dai Yanpeng
Published: January 2024

Obesity (OB) is a prevalent metabolic disorder. With the advancement of the economy, the prevention and treatment of obesity is a big problem for the global community. The methods to lose weight include exercise, diet, medicine, and surgery. Compared with other methods, diet regulation is safer and more effective. Hawthorn fruit has the effect of reducing weight, but the mechanism of effectiveness are not clear. In this study, obesity model rats are used to conduct scientific pharmacological research on hawthorn flavonoids. Hawthorn flavonoids can effectively improve the body weight, lipid accumulation, and lipid levels of obese rats. The contents of the colon of rats are analyzed using 16S rDNA sequencing technology. The intestinal microflora in obese rats changed significantly after flavonoids treatment, and they tended to be the control group. Based on liquid chromatography‐mass spectrometry, serum metabolomics showed that the metabolites in the serum changed significantly, after hawthorn flavonoids treatment. Hawthorn flavonoids are especially involved in the biological processes of grade bile acid biosynthesis, histidine metabolism, and lipid metabolism. Pearson correlation analysis showed that the disorder of intestinal microorganisms is connected to changes in serum metabolites. These findings give a new idea about how hawthorn flavonoids help with obesity.
Earth‐Abundant Fe‐Mn‐Based Compound Cathodes for Sodium‐Ion Batteries: Challenges and Progress
Authors: Peng Bo , Zhou Zihao , Shi Ji , Huang Xing , Li Yongtao , Ma Lianbo
Published: January 2024

Sodium‐ion batteries (SIBs) with high energy/power density and low‐cost characteristics are deemed to be one of the best replacements to lithium‐ion batteries for utilizing in large‐scale electric energy storage (EES) devices. Fe‐Mn‐based cathode materials take the leading position in realizing high‐performance SIBs because of their high capacity, environment‐friendly, earth abundant, and low‐cost features, exhibiting huge commercial potential. However, the energy density and cyclic stability are still limited so far, considering the increasing demands for practical applications. In this review, aiming to better understanding the research level and currently existed sore points, the research progress is overviewed for several types of Fe‐Mn‐based cathode materials, including layered oxides, polyanionic compounds and Prussian blue analogues, and refine the electrochemical storage mechanism and structure–performance relationship. Finally, the representative electrochemical performances of these three kinds of cathode materials is summarized, compare the advantages and disadvantages of various materials, point out the existing key scientific problems of these materials, and propose the direction of development in near future. This review makes a thoroughly understanding for Fe‐Mn‐based cathode materials, providing new guidance for future research on SIBs toward real‐world applications.
Dynamic Time‐Dependent Emission in Solution and Stable Dual Emission in Solid Matrix Exhibited by a Single‐Component Fluorescence System
Authors: Chen Dengli , Bao Cheng , Zhang Liangliang , Zhang Qiaona , Wu Zhiyin , Li Zheng‐Yi , Sun Xiao‐Qiang , Wang Leyong , Xiao Tangxin
Published: January 2024

Organic luminescent materials with time‐dependent emission colors show promising applications in the fields of chemical sensing, high‐resolution bioimaging, and high‐security information encryption. Herein a time‐dependent fluorescence system based on a spirocyclic scaffold‐bridged cyanostilbene dimer (SDCS) as the single component in a mixed CH3CN/H2O solvent is presented. Specifically, the original orange‐emitting nanoparticles prepared from SDCS by reprecipitation can transform into green‐emitting nanosheets over time driven by supramolecular self‐assembly. It is worth noting that such a transformation rate can be controlled by tuning the water fraction. Based on these unique properties, fluorescent binary codes are developed, enabling time‐dependent information encryption with a higher level of security. Moreover, the dual color can be individually fixed by solid matrices such as hydrogel or powder. The obtained luminescent powders are successfully used in two‐color fluorescence imaging of latent fingerprints. This work demonstrates the use of a supramolecular strategy to control multiple emissions in a single‐component system for multifunctional applications.
Unraveling and Harnessing the Immune Response at the Cell–Biomaterial Interface for Tissue Engineering Purposes
Authors: ten Brink Tim , Damanik Febriyani , Rotmans Joris I. , Moroni Lorenzo
Published: January 2024

Biomaterials are defined as “engineered materials” and include a range of natural and synthetic products, designed for their introduction into and interaction with living tissues. Biomaterials are considered prominent tools in regenerative medicine that support the restoration of tissue defects and retain physiologic functionality. Although commonly used in the medical field, these constructs are inherently foreign toward the host and induce an immune response at the material–tissue interface, defined as the foreign body response (FBR). A strong connection between the foreign body response and tissue regeneration is suggested, in which an appropriate amount of immune response and macrophage polarization is necessary to trigger autologous tissue formation. Recent developments in this field have led to the characterization of immunomodulatory traits that optimizes bioactivity, the integration of biomaterials and determines the fate of tissue regeneration. This review addresses a variety of aspects that are involved in steering the inflammatory response, including immune cell interactions, physical characteristics, biochemical cues, and metabolomics. Harnessing the advancing knowledge of the FBR allows for the optimization of biomaterial‐based implants, aiming to prevent damage of the implant, improve natural regeneration, and provide the tools for an efficient and successful in vivo implantation.
Metal‐Organic Framework‐Based Nanomedicines for Ferroptotic Cancer Therapy
Authors: Song Yue , Xu Xinran , Wang Zheng , Zhao Yanjun
Published: January 2024

As an iron‐dependent, non‐apoptosis, regulated cell death (RCD) modality, ferroptosis has gained growing attention for cancer therapy. With the development of nanomaterials in the biomedical field, ferroptotic cancer nanomedicine is extensively investigated. Amongst various nanomaterials, metal‐organic frameworks (MOFs) are hybridized porous materials consisting of metal ions or clusters bridged by organic linkers. The superior properties of MOFs, such as high porosity and cargo loading, ease of surface modification, and good biocompatibility, make them appealing in inducing or sensitizing ferroptotic cell death. There are remarkable achievements in the field of MOF‐based ferroptosis cancer therapy. However, this topic is not reviewed. This review will introduce the fundamentals of MOF and ferroptosis machinery, summarize the recent progress of MOF‐based ferroptotic anticancer drug delivery, discuss the benefits and problems of MOFs as vehicles and sensitizers for cancer ferroptosis, and provide the perspective on future research direction on this promising field.
Visible‐Light‐Driven Cyclizations
Authors: Oueis Emilia , Elkadi Mirella , Rios Ramon
Published: January 2024

In recent years, the interest to develop cyclizations promoted by visible light has been gaining a lot of attention due to its sustainability aspect. In this review, we summarize the most important advances in this period by describing the methods used to generate different ring sizes, while focusing on the mechanistic details of these reactions.
Catalytic Metal‐Gated Nano‐Sheet Field Effect Transistor and Nano‐Sheet Tunnel Field Effect Transistor Based Hydrogen Gas Sensor‐ A Design Perspective
Authors: Bansal Geetika , Tiwari Aditya , Majumdar Budhaditya , Mukhopadhyay Subhas C. , Kanungo Sayan
Published: January 2024

In this work, for the first time, the catalytic metal gate (CMG) based nanosheet Field Effect Transistor (NSFET) and nanosheet Tunnel Field Effect Transistor (NSTFET) are proposed for nano‐scale device dimensions, and the different design aspects of catalytic metal gate (CMG)‐based transduction for Hydrogen (H2) sensing are extensively investigated using numerical device simulation. The influence of applied biasing conditions and structural parameter specifications on the sensing performance of CMG‐NSFET and CMG‐NSTFET are methodically analyzed from device electrostatics and carrier transport mechanisms. Furthermore, the relative maximum sensitivity variations with H2‐partial pressure, ambient temperature, and the presence of ambient Oxygen are comprehensively studied. The study reveals that compared to CMG‐NSFET, the CMG‐NSTFET demonstrates a high immunity against bias and doping variations, with a notably higher (> 50%) sensitivity within low H2partial pressures (10−15– 10−10 Torr). Next, the sensing performance of CMG‐NSTFET is systematically optimized through a band‐gap and gate‐stack engineering approach, leading to a 180% to 650% sensitivity improvement from lower (10−15 Torr) to higher (10−5 Torr) range of H2partial pressure. Finally, the performance of optimized CMG‐NSFET and CMG‐NSTFET are extensively benchmarked against other reported nanostructured CMG‐FET and TFET‐based H2gas sensors, exhibiting a notably higher sensitivity in the proposed sensors.
A High‐Capacity and High‐Voltage Aqueous Zn‐Polymer Battery with Self‐Charging Function
Authors: Xu Qiuju , Zhang Xinxin , Yuan Xiangcheng , Zhang Weixuan , Li Yiqing , Zhang Yuegang , Liu Jinzhang
Published: January 2024

Organic electrodes in aqueous batteries rely on electrochemical redox reactions for charge and discharge. The organic cathode at a discharged state can be spontaneously oxidized when exposed to air, which facilitates the development of air‐charging batteries. However, polymer cathodes in aqueous rechargeable Zn‐ion batteries (ARZIBs) generally show low discharge median voltage below 1 V. Herein, a new polymer cathode is reported that is prepared by electrodepositing poly(4‐hydroxydiphenylamine, HDPA) onto mesoporous activated carbon and shows a relatively high discharge voltage plateau at ≈1.1 V when coupled with a Zn anode. Its self‐charging performances at different conditions are investigated. Also, a high areal capacity of 3.8 mAh cm−2 of the cathode is achieved. The poly(4‐HDPA) contains both amino and carbonyl groups, and the carbonyl group is found to be fully responsible for redox reaction. Further investigation suggests that both Zn2+ and H+ in the ZnSO4 electrolyte participate in the charge storage process, and the H+ plays a dominant role. The air‐charging mechanism of this polymer cathode is elucidated both experimentally and theoretically. To demonstrate the practical applications, prototypes of box‐shaped battery pack are air‐charged to either drive a mini electric fan or light up LEDs.
Toward Eco‐Friendly E‐Waste Recycling: New Perspectives on Ozone‐Assisted Gold Leaching
Authors: Stojanovski Kevin , Briega‐Martos Valentin , Escalera‐López Daniel , Gonzalez Lopez Francisco Javier , Smiljanic Milutin , Grom Matic , Baldizzone Claudio , Hodnik Nejc , Cherevko Serhiy
Published: January 2024

Global demand for more effective methods to reclaim gold from electronic waste (E‐waste) has never been greater. Alternatives to hydrometallurgical methods, such as cyanide, are still limited. This work examines utilizing ozone and chlorides to recycle Au from E‐waste. It is started with a fundamental investigation of Au dissolution processes on the extended surface of Au polycrystalline and Au nanoparticulated electrodes. An online electrochemical scanning flow cell coupled with inductively coupled plasma mass spectrometry quantifies the rates and amounts of Au leaching. Identical‐location scanning electron microscopy (IL‐SEM) further correlates dissolution events with electrode morphological changes. It is demonstrated that ozone in the electrolyte imposes an anodic potential on the electrode, leading to anodic Au dissolution. Passivation disappears when small amounts of chlorides are added to the electrolyte, significantly enhancing the leaching yield. IL‐SEM images of gold nanoparticles (NPs) before and after exposure to ozone reveal heterogeneity in NP size‐dependent dissolution, showing higher dissolution for smaller particles. An effective Au leaching procedure is further demonstrated in a lab‐scale reactor using real E‐waste where almost complete recovery of Au is achieved. This research suggests that with engineering optimization in reactor applications based on ozone‐stimulated gold, dissolution can pave the way for environmentally friendly gold recycling.
Dynamic Shape Change of Liquid Crystal Polymer Based on An Order‐Order Phase Transition
Authors: Yang Rong , Wang Yahui , Yao Hongjing , Li Yanqing , Chen Li , Zhao Yue , Wang Yu‐Zhong
Published: January 2024

Liquid crystal actuators conventionally undergo shape changes across an order‐disorder phase transition between liquid crystal (LC) and isotropic phases. In this study, we introduce an innovative Liquid Crystal Polymer (LCP) actuator harnessing an order‐order LC phase transition mechanism. The LCP film is easily stretchable within the LC phase, facilitated by the π–π stacking of phenyl groups serving as robust physical crosslinking points, and thereby transforms to a stable monodomain structure. The resultant monodomain LCP actuator shows a distinctive reversible dynamic shape change, exhibiting extension followed by contraction along the LC director on cooling. The extension is propelled by the reversible smectic C to smectic A phase transition, and the contraction is attributed to the re‐entry to the smectic C phase from smectic A phase. Thermal annealing temperature determines this peculiar dynamic shape change, which occurs during both heating and cooling processes. This pivotal attribute finds manifestation in gripper and flower‐shaped actuators, adeptly executing grabbing and releasing as well as blooming and closure motions within a single thermal stimulation. In essence, our study introduces an innovative approach to the realm of LCP actuators, ushering in a new avenue for the design and fabrication of versatile and dynamically responsive LCP actuators.
Massive Molecular Motion in Crystal Leads to an Unexpected Helical Covalent Polymer in a Solid‐state Polymerization
Authors: Khazeber Ravichandran , Kana Gautham S. , Sureshan Kana M.
Published: January 2024

We designed a proline‐derived monomer with azide and alkene functional groups to enable topochemical ene‐azide cycloaddition (TEAC) polymerization. In its crystal, the monomer forms supramolecular helices along the ‘a’ axis through various non‐covalent interactions. Along the ‘c’ axis, the molecules arrange themselves head‐to‐tail in a wave‐like pattern, positioning the azide and alkene groups of adjacent molecules in close proximity and anti‐parallel orientation, complying with Schmidt's criteria for topochemical reaction. This prearranged configuration was expected to facilitate smooth topochemical polymerization, resulting in a 1,4‐triazoline‐linked polymer. Upon heating, the monomer underwent TEAC polymerization in a remarkable single‐crystal‐to‐single‐crystal fashion, but, to our surprise, it yielded an unexpected covalent helical polymer linked by 1,5‐disubstituted triazoline units. Remarkably, the crystal avoids the ready‐to‐react arrangement for polymerization, but connects monomer molecules within the supramolecular helix through the cycloaddition of azide and alkene groups, even though they are not in close proximity nor in the expected orientation. This unexpected path, involving a substantial 134° rotation of the alkene group, yields hitherto unknown 1,5‐disubstituted triazoline product regiospecifically. This study serves as a cautionary reminder that relying solely on topochemical postulates for predicting reactivity can sometimes be misleading.
Design of 3D‐Printed Heterogeneous Reactor Systems To Overcome Incompatibility Hurdles when Combining Metal and Enzyme Catalysis in a One‐Pot Process
Authors: Salitra Nadiya , Gurauskis Jonas , Gröger Harald
Published: January 2024

Combining chemo‐ and biocatalysis enables the design of novel economic and sustainable one‐pot processes for the preparation of industrial chemicals, preferably proceeding in water. While a range of proofs‐of‐concept for the compatibility of such catalysts from these two different “worlds of catalysis” have recently been demonstrated, merging noncompatible chemo‐ and biocatalysts for joint applications within one reactor remained a challenge. A conceptual solution is compartmentalization of the catalytic moieties by heterogenization of critical catalyst components, thus “shielding” them from the complementary noncompatible catalyst, substrate or reagent. Exemplified for a one‐pot process consisting of a metal‐catalyzed Wacker oxidation and enzymatic reduction as noncompatible individual reactions steps, we demonstrate that making use of 3D printing of heterogeneous materials containing Cu as a critical metal component can overcome such incompatibility hurdles. The application of a 3D‐printed Cu‐ceramic device as metal catalyst component allows an efficient combination with the enzyme and the desired two‐step transformation of styrene into the chiral alcohol product with high overall conversion and excellent enantioselectivity. This compartmentalization concept based on 3D printing of heterogenized metal catalysts represents a scalable methodology and opens up numerous perspectives to be used as a general tool also for other related chemoenzymatic research challenges.
A study on the performance of a swirling–straight composite nozzle
Authors: Yu Dongxing , Li Shuchao , Zhang Jun , Wang Ning , Ling Zongyu
Published: January 2024

The nozzle is the key component of water mist fire extinguishing system. As a response to the problems of small injection angle associated with straight jet nozzles and the weak axial momentum of swirl nozzles, a swirling–straight composite nozzle is designed in this work. The comparison with a straight jet nozzle and a pressure swirl nozzle shows that the swirling–straight composite nozzle has a larger axial momentum and better injection angle. Under the same pressure, the volume flow of the swirling–straight composite nozzle is more than 27% of the pressure swirl nozzle, and the injection angle was more than 65% of straight jet nozzle. The numerical model of the swirling–straight composite nozzle is established. Meantime, the internal flow field characteristics and the influence of the straight jet aperture on the performance are studied. The results demonstrate that the straight jet fluid and swirling fluid can be mixed well in the nozzle, and a larger axial momentum and tangential momentum can be obtained. With the increase of the straight jet aperture, the swirl effect in the nozzle becomes weaker, the injection angle becomes smaller, and the axial momentum improves. When the straight jet aperture increases from 1.1 to 1.9 mm, the straight jet volume flow at the nozzle inlet increases by 127%, and the injection angle reduces by 40%.