bluuebunny/crossref_metadata_2025 huggingface dataset:
Environmental variability within the Chinese desert-loess transition zone over the last 20000 years
Authors: Zhou W. J. , Dodson J. , Head M. J. , Li B. S. , Hou Y. J. , Lu X. F. , Donahue D. J. , Jull A. J. T.
Published: July 2002

The desert/loess transition zone in northern China is sensitive to climate variability, which is controlled mainly by the relative strengths of the East Asian summer and winter monsoons. Sandy loess layers found in the Loess Plateau and palaeosol sequences found in the sandy desert demonstrate latitudinal shifts of the southern desert margin over the last 20000 years. Stratigraphic investigations together with radiocarbon and some thermoluminescence dating, show that during the last glacial maximum the desert margin was at its most southerly position (38°N). During the early Holocene, it moved northward about three degrees in latitude (41°N). At present, the desert margin is again close to its most southerly position (38°21 N), yet the northern boundary position of modern summer monsoon activity is placed at 41°45 N, which is close to the estimated Holocene Optimum desert margin (41°N). This situation cannot be explained from natural climate models. Hence, an external driving mechanism needs to be considered, and the most obvious one is that caused by human activity on the natural environment over the last 3000 years. Historical evidence tends to reinforce this consideration.
1300 years of climatic history for Western Central Asia inferred from tree-rings
Authors: Esper Jan , Schweingruber Fritz H. , Winiger Matthias
Published: July 2002

More than 200 000 ring-width measurements from 384 trees were obtained for 20 individual sites ranging from the lower to upper local timber-lines in the Northwest Karakorum of Pakistan and the Southern Tien Shan of Kirghizia. Samples were obtained predominantly from juniper species (Juniperus) and were analysed to reconstruct regional climatic variation patterns in Western Central Asia since ad 618. Site distri bution represents diverse ecological conditions (e.g., combinations of temperature and moisture stress) within the Karakorum and Tien Shan mountains, permitting both intra-montane and inter-montane comparisons of chronologies. Three different types of chronologies reflecting interannual-, decadal- and centennial-scale ring- width variations were calculated: a statistic skeleton-plotting technique was used to identify ring-width pointer years (interannual); a 101-year kernel filter was used to identify decadal-scale variations; and, for a subset of long-lived trees, the mean ring-width of the entire single series was used to identify centennial trends. After extracting and calibrating each of these three distinct wavelengths in ring-width variation, the results were combined into a comprehensive reconstruction reflecting primarily temperature fluctuations in Western Central Asia since ad 618. The nature and the temporally changing strength of the climatic signals of this reconstruction are discussed in detail. A maximum latewood density record of Pinus tienschanica from Central Tien Shan was used as a predictor series to calibrate and validate tree-ring-width variation. In so doing, we link our results to the circumpolar maximum latewood-density network (Briffa et al., 1998a; 1998b; Schweingruber and Briffa, 1996).
The impact of climate and shore-level displacement on the late-Holocene environmental development of Havstens Fjord and Koljö Fjord, Swedish west coast
Authors: Gustafsson Mikael , Nordberg Kjell
Published: July 2002

Koljö Fjord and Havstens Fjord on the Swedish west coast are, like many silled fjords in Scandinavia, characterized by strong stratification and stagnant bottom water with periodically occurring low-oxygen and anoxic conditions. High organic production together with a stable water-column, very low tidal activity and existence of the sill create an ideal foundation for low-oxygen conditions to develop. The aim of this study was to find out how the fjord environments developed during the later part of the Holocene and, especially, how and when the low-oxygen conditions evolved. To achieve these goals, sediment cores were dated (210Pb and 14C) and x-rayed, the distribution of benthic foraminifera was analysed and their content of the stable isotopes d18O and d13C was investigated. In both fjords, the climate proved to be of importance for the environment and it seems that increased freshwater runoff increased the primary production between 500 bc and ad 500. Increasing freshwater runoff not only increased primary production but, at least since ad 1880, also made the water stratification stronger and the deep water more stagnant. Stagnant conditions are the main cause of the development of periodic anoxia and formation of laminated sediments in Koljö Fjord from ad 1930 to 1980 and in Havstens Fjord from ad 1950. In Koljö Fjord, the isostatic land rise and the shallow sill are the most important reasons for a general change from an almost normal saline deep-water environment to a brackish environment in ad 500. At that time the sill depth passed the pycnocline mean depth of 15 m. For Koljö Fjord, this is a threshold value of the depth for the quality of the deep water, marine or brackish.
A general model of paraglacial landscape response
Authors: Ballantyne Colin K.
Published: July 2002

A unifying attribute of all forms of paraglacial response is that deglaciation results in the exposure of unstable or metastable sediment sources that are subsequently tapped by a wide variety of processes over a wide range of timescales. The ‘paraglacial period’ in different geomorphological contexts is therefore con ditioned by two variables: glacially conditioned sediment release and rate of sediment reworking. Under steady-state conditions, the latter may be approximated by an exhaustion model in which sediment yield is related to the amount of remaining ‘available’ sediment by a negative exponential function. This model offers an approximation for the behaviour of primary paraglacial systems in which glacigenic sediment sources are not replenished. The long-term behaviour of secondary (primarily ‘ uvial) paraglacial systems in which sediment inputs include both in situ and reworked glacigenic sediment appears intrinsically more complex, but consistent with an exhaustion model if initial sediment availability is greatest in upland tributary basins and declines as catchment size increases. In all paraglacial systems, however, the temporal pattern of sediment release is sensi tive to external perturbation, which has the effect of prolonging and/or rejuvenating sediment release, and may result in renewed paraglacial sediment release millennia after termination of the initial (deglacial) period of paraglacial activity.
Multi-state models for bone marrow transplantation studies
Authors: Klein John P , Shu Youyi
Published: July 2002

High-dose chemotherapy followed by stem cell recovery, more commonly called a bone marrow transplant, is a common treatment for a number of diseases. This article examines four problems commonly encountered when dealing with bone marrow transplant studies. First, we look at the problem of competing causes of failure and at methods based on a multi-state model to estimate meaningful probabilities for these risks. Second, we examine methods for estimating the prevalence of an intermediate condition, here the prevalence of chronic GVHD. Third, we look at the problem of modeling the post transplant recovery process and we provide two examples of how these estimates can be used to assess dynamically a patient’s prognosis or how these probabilities can be used to design trials of new therapy. Finally, we present an estimate of a new measure of treatment efficiency, the current leukemia free survival function, which is derived from a multi-state model approach.
Inference for multi-state models from interval-censored data
Authors: Commenges D
Published: July 2002

Clinical statuses of subjects are often observed at a finite number of visits. This leads to interval-censored observations of times of transition from one state to another. The likelihood can still easily be written in terms of both transition probabilities and transition intensities. In homogeneous Markov models, transition probabilities can be expressed simply in terms of transition intensities, but this is not the case in more general multi-state models. In addition, inference in homogeneous Markov models is easy because these are parametric models. Non-parametric approaches to non-homogeneous Markov models may follow two paths: one is the completely non-parametric approach and can be seen as a generalisation of the Turnbull approach; the other implies a restriction to smooth intensities models. In particular, the penalized likelihood method has been applied to this problem. This paper gives a review of these topics.
Postcolonialism and native American geographies: the letters of Rosalie La Flesche Farley, 1896-1899
Authors: Morin Karen M.
Published: July 2002

As the privileged daughter of the last traditional chief of the Omaha Indians, Rosalie La Flesche Farley acted as business manager for the Omaha during a period of changing land tenure and scandalous land loss. The letters I examine here discuss the spaces of colonial relations into which Rosalie was tied during the allotment, selling, and leasing of Omaha land in the late nineteenth century. While there is an acknowledged ‘problem’ with a postcolonial interpretation of US historical geography, a postcolonial analysis of Rosalie’s writing allows for a measure of understanding about the numerous conflicting, obviously distraught, but ultimately personally advantageous spaces of ‘Indianness’ she occupied. The gendered and racialized spaces and subjectivities she occupied were products of American colonialism and her strategies of survival within it.
Virtual Reality and Simulation: Training the Future Emergency Physician
Authors: Reznek Martin , Harter Phillip , Krummel Thomas
Published: July 2002

The traditional system of clinical education in emergency medicine relies on practicing diagnostic, therapeutic, and procedural skills on live patients. The ethical, financial, and practical weaknesses of this system are well recognized, but the alternatives that have been explored to date have shown even greater flaws. However, ongoing progress in the area of virtual reality and computer‐enhanced simulation is now providing educational applications that show tremendous promise in overcoming most of the deficiencies associated with live‐patient training. It will be important for academic emergency physicians to become more involved with this technology to ensure that our educational system benefits optimally.
Utilization of the Ottawa Ankle Rules by Nurses in a Pediatric Emergency Department
Authors: Karpas Anna , Hennes Halim , Walsh‐Kelly Christine M.
Published: July 2002

Objectives: To determine the ability of pediatric emergency department (ED) nurses to accurately apply the Ottawa Ankle Rules (OAR) and to evaluate whether the rate of negative ankle radiographs can be reduced by incorporating the OAR into an existing collaborative practice protocol (CPP). Methods: The authors' ED currently uses a CPP in which patients with ankle pain, swelling, deformity, or decreased range of motion on primary nursing assessment undergo radiography prior to physician evaluation. A cross‐sectional study was conducted between June and November 2000. Patients aged 5‐19 years with an ankle injury who met at least one of the CPP criteria were eligible for enrollment. The OAR were applied by the primary nurse after initial assessment. Ankle radiographs were ordered for all enrolled patients. The interobserver variability between nurses was evaluated on a random sample. Results: One hundred ninety subjects were enrolled in the study. The OAR were correctly interpreted by nurses in 98.4% of subjects. Agreement on the interobserver reliability sample was 100%. Of the 185 subjects, 31 (16.8%) had positive radiographs. Positive OAR results were noted in 30 of 31 subjects with positive radiographs. The sensitivity of the OAR was 97% (95% CI = 0.82 to 0.99) with a specificity of 25% (95% CI = 0.18 to 032). Use of the OAR would have reduced the radiography rate by 21%. Conclusions: Trained nurses can accurately apply and interpret the OAR. The incorporation of the OAR into the nursing assessment of children with acute ankle injuries may reduce the number of radiographs ordered.
Predictors of Genitorectal Injury in Female Victims of Suspected Sexual Assault
Authors: Sachs Carolyn J. , Chu Lawrence D.
Published: July 2002

Objective: Legal decisions in sexual assault cases often hinge on the presence or absence of genitorectal injury. Unfortunately, the forensic literature does not explain why some victims sustain genitorectal injury and others do not. This study explores possible predictors of genitorectal injury in adult female sexual assault victims. Methods: This retrospective cross‐sectional analysis forms the derivation set for a larger planned prospective analysis. The authors extracted data describing consecutive female sexual assault victims who met inclusion criteria between July 1995 and July 1998. Exclusion criteria included male sex, lack of estrogen in females, consensual intercourse within the previous 72 hours, and lack of penetration during the assault. The authors explored associations between genitorectal injury and seven demographic variables, nine assault characteristics, and the time between assault and exam or postcoital interval (PCI). Variables thought to be predictive were incorporated into a logistic regression model. Results: Five hundred forty‐eight sexual assault victims were seen during the study time period; 209 of these met the inclusion criteria. Logistic regression controlling for important covariates showed an increase risk of genitorectal injury with a PCI < 24 hours (OR 7.47, 95% CI = 1.78 to 31.35), physical/verbal resistance (OR 5.96, 95% CI = 1.21 to 29.36), rectal penetration (OR 7.47, 95% CI = 1.05 to 53.07), and greater than high school education (OR 7.13, 95% CI = 1.03 to 49.65). Conclusions: This study presents an important first look at variables that may predict genitorectal injury in sexual assault victims. Future studies that examine more data are needed to corroborate this preliminary derivation set analysis.
Assessment of Clinically Significant Changes in Acute Pain in Children
Authors: Bulloch Blake , Tenenbein Milton
Published: July 2002

Objective: To quantify, using two pain assessment scales, the amount of change in pain severity required to achieve a clinically significant improvement in pain in children presenting to a pediatric emergency department (ED) with pain. Methods: Prospective, descriptive study involving all children presenting to a pediatric ED between 5 and 16 years of age inclusive with acute pain. Children were excluded if they 1) were intoxicated or had altered sensorium, 2) were clinically unstable, 3) were non‐English‐speaking, or 4) were developmentally delayed. Written informed consent was obtained. Children were asked to mark their current pain severity on the standardized Color Analogue Scale (CAS) and Faces Pain Scale (FPS). After each pain control intervention the child was asked to repeat these measurements and to describe whether his or her pain was “much less,”“a little less,”“about the same,”“a little worse,” or “much worse” compared with before. This process was repeated until the child was discharged from the ED or had a score of zero. The main outcome measure was the smallest change on the CAS or FPS necessary to cause the child to describe his or her pain as a “little less.” This was defined as the clinically significant change in pain. The “ideal” change in pain was defined as the amount of change necessary for the child to describe the pain as “much less” or at which point the child thought he or she no longer required any medicine to help the pain go away. Results: One hundred twenty‐one children were enrolled with a mean age of 9.8 years (SD ± 3.15). Males accounted for 56%. Pain was traumatic in 65% and nontraumatic in 35%. A total of 153 pain comparisons were made using the CAS and 154 using the FPS. Only three children complained that their pain got worse (two a little worse and one much worse). Pain was described as “the same” in 20. Of the 60 pain comparisons judged to be a “little less,” the CAS score changed by a median of 2.0 cm [interquartile ratio (IQR) 1‐3], and the FPS by 1.0 face (IQR 1‐2). In the 71 children who judged their pain to be “much less,” the CAS decreased by a median of 4.0 cm (IQR 2‐5) and the FPS by 2.0 faces (IQR 2‐3). Conclusions: The assessment and treatment of pain in children are an important component of pediatric practice, especially in the ED. This study provides health care professionals and clinical investigators the information necessary to assess whether their method of pain control in children is clinically relevant.
Filming of Patients in Academic Emergency Departments
Authors: Marco Catherine A. , Larkin Gregory L. , Silbergleit Robert
Published: July 2002

With increasing availability and utilization of advanced technologic modalities in medicine, questions frequently arise regarding the appropriate use of recorded images of patients. While recorded images (photography, video, etc.) of patients may often be appropriate for documentation, medical record use, peer review, and teaching, the nonmedical use of recorded images for entertainment or commercial purposes is more problematic, both ethically and procedurally. Practices regarding filming of patients in academic emergency departments are reviewed, and suggested guidelines are provided regarding the appropriate and inappropriate filming of patients.
Evaluating Acceptance and Understanding of Risk in the Emergency Department:Are All Risk Statements Created Equally?
Authors: Feldman James A. , Risbano Michael , Mitchell Patricia M. , Metha Supriya D. , Fish Susan S.
Published: July 2002

Abstract. Objective: To determine whether mathematically equivalent but conceptually different presentations of risk from radioactive isotope exposure might affect the rate of agreement to participate in a hypothetical research study.

Methods: This was a prospective study of consenting English‐speaking subjects more than 18 years of age who were asked whether they would agree to participate in a mock study when presented with six mathematically equivalent statements of research‐related risk. Participants were classified as recognizing the equivalence of the risk statements if they accepted all or refused all of the risk statements.

Results: Three hundred forty‐six subjects were enrolled. There were 55 subjects (16%; 95% CI = 12% to 20%) who refused all of the six risk statements, and 23 participants (6.7%; 95% CI = 4% to 9%) who accepted all of the given risk statements. Most of the participants (77%; 95% CI = 73% to 82%) did not recognize that the six risk statements were equivalent and agreed to some, or did not understand some of the risk statements. In stepwise multivariate logistic regression, being white, being of older age, and having higher education were associated with a higher likelihood of accepting or rejecting all six of the risk statements.

Conclusions: Ethnicity, age, and education affected whether patients recognized the equivalence of six risk statements for a hypothetical study of low‐dose radiation. Risk acceptance may be more likely when familiar concepts are used to express research risks. Researchers must focus on strategies that enhance the understanding of research risks and address the reasons for nonparticipation by subjects who are younger, of different ethnic or cultural background, or of lower education.
Heliox as a Temporizing Measure for Pediatric Foreign Body Aspiration
Authors: Brown Lance , Sherwin Thomas , Perez Javier E. , Perez Donald U.
Published: July 2002

Abstract. The authors report their experience with using heliox as a temporizing measure for an aspirated foreign body in a young child.
Precocious Puberty Among Children and Adolescents With Hidradenitis Suppurativa
Authors: Mastacouris Nicole , Midgette Bria , Strunk Andrew , Garg Amit
Published: September 2024

This case-control study examines the association of precocious puberty with hidradenitis suppurativa among US children and adolescents.
Implementing Culturally Tailored Outpatient Surgical Care
Authors: Ore Ana Sofia , Areán-Sanz Rodrigo , Messaris Evangelos
Published: September 2024

This article discusses the Latinx Colorectal Surgery Clinic, which was created to provide linguistically and culturally tailored surgical care.
Video Analysis of Concussion Among Slap Fighting Athletes
Authors: Lavadi Raj Swaroop , Kumar Rohit Prem , Kann Michael R. , Shah Manan J. , Hamilton D. Kojo , Maroon Joseph C. , Agarwal Nitin
Published: September 2024

This cross-sectional study assesses the risk of concussion among 56 slap fighting athletes via video analysis of 78 slap fighting matches.
An Update on the Survival of the First 50 Face Transplants Worldwide
Authors: Homsy Pauliina , Huelsboemer Lioba , Barret Juan P. , Blondeel Phillip , Borsuk Daniel E. , Bula Daniel , Gelb Bruce , Infante-Cossio Pedro , Lantieri Laurent , Mardini Samir , Morelon Emmanuel , Nasir Serdar , Papay Francis , Petruzzo Palmina , Rodriguez Eduardo , Özkan Özlenen , Özmen Selahattin , Pomahac Bohdan , Lassus Patrik
Published: September 2024

Importance

Since 2005, a total of 50 face transplants have been reported from 18 centers in 11 countries. The overall survival of the grafts has not yet been established.

Objective

To assess the survival of the face transplant grafts and evaluate factors potentially influencing it.

Design, Setting, and Participants

Data on all the transplants included in this multicenter cohort study were collected at participating transplant centers for updated nonpublished data, supplemented with literature review for nonparticipating centers. Data from 2005 until September 2023, were included. Data were analyzed from November 11, 2005, through September 18, 2023. Patients included the first 50 patients in the world to have received a face transplant.

Exposure

Face transplant graft.

Main Outcomes and Measures

The primary outcome was the overall survival of the face transplant graft, defined as either transplant loss or patient death. The secondary outcome was the number of acute rejection episodes per year.

Results

The 50 transplants were performed on 39 men (81%) and 9 women (19%) with a median age of 35 (range, 19-68) years at the time of the transplant. The median follow-up time was 8.9 (range, 0.2-16.7) years. During the follow-up, 6 transplants were lost with 2 patients retransplanted. There were 10 patients who died, 2 of whom had lost a transplant. The 5- and 10-year survival of the transplants was 85% (SD, 5%) and 74% (SD, 7%), respectively. The sequential number of the transplant in the world was a significant predictor of survival (hazard ratio, 95; 95% CI, 90-100; P < 05). The median number of acute rejection episodes per year was 1.2 (range, 0-5.3) for the transplants that were lost and 0.7 (range, 0-4.6) for the transplants that survived. No correlation with patient and transplant variables was detected for either the transplant survival or the number of rejection episodes.

Conclusions and Relevance

In this study, the overall survival of the face transplants is encouraging. These data suggest that the acceptable long-term survival of face transplants makes them a reconstructive option for extensive facial defects.
Language abnormalities in Alzheimer's disease indicate reduced informativeness
Authors: Bayat Sabereh , Sanati Mahya , Mohammad‐Panahi Mehrdad , Khodadadi Amirhossein , Ghasimi Mahdieh , Rezaee Sahar , Besharat Sara , Mahboubi‐Fooladi Zahra , Almasi‐Dooghaee Mostafa , Sanei‐Taheri Morteza , Dickerson Bradford C. , Rezaii Neguine
Published: September 2024

Objective

This study aims to elucidate the cognitive underpinnings of language abnormalities in Alzheimer's Disease (AD) using a computational cross‐linguistic approach and ultimately enhance the understanding and diagnostic accuracy of the disease.

Methods

Computational analyses were conducted on language samples of 156 English and 50 Persian speakers, comprising both AD patients and healthy controls, to extract language indicators of AD. Furthermore, we introduced a machine learning‐based metric, Language Informativeness Index (LII), to quantify empty speech.

Results

Despite considerable disparities in surface structures between the two languages, we observed consistency across language indicators of AD in both English and Persian. Notably, indicators of AD in English resulted in a classification accuracy of 90% in classifying AD in Persian. The substantial degree of transferability suggests that the language abnormalities of AD do not tightly link to the surface structures specific to English. Subsequently, we posited that these abnormalities stem from impairments in a more universal aspect of language production: the ability to generate informative messages independent of the language spoken. Consistent with this hypothesis, we found significant correlations between language indicators of AD and empty speech in both English and Persian.

Interpretation

The findings of this study suggest that language impairments in AD arise from a deficit in a universal aspect of message formation rather than from the breakdown of language‐specific morphosyntactic structures. Beyond enhancing our understanding of the psycholinguistic deficits of AD, our approach fosters the development of diagnostic tools across various languages, enhancing health equity and biocultural diversity.
Assessment of central vein sign and paramagnetic rim lesions in pediatric multiple sclerosis
Authors: Margoni Monica , Preziosa Paolo , Pagani Elisabetta , Storelli Loredana , Gueye Mor , Moiola Lucia , Filippi Massimo , Rocca Maria A.
Published: September 2024

The evaluation of white matter lesions (WMLs) showing the central vein sign (CVS) and paramagnetic rim lesions (PRLs) has been suggested to enhance the diagnostic work‐up of adult multiple sclerosis (MS). We aimed to evaluate the fulfillment of different CVS criteria and the added value of PRLs in 22 pediatric MS patients. Eleven patients (50%) fulfilled the 40%‐rule threshold. Nineteen (86%) patients had ≥3 CVS+ WMLs or ≥1 PRL, whereas 17 (77%) had ≥6 CVS+ WMLs or ≥1 PRL. A simplified CVS‐based approach, with the combined evaluation of ≥1 PRL in patients with ≥6 CVS+ WMLs, may improve MS diagnosis in pediatric patients.
Radiation Hardness and Defects Activity in PEA2PbBr4 Single Crystals
Authors: Ciavatti Andrea , Foderà Vito , Armaroli Giovanni , Maserati Lorenzo , Colantoni Elisabetta , Fraboni Beatrice , Cavalcoli Daniela
Published: September 2024

Metal halide perovskites (MHPs) are low‐temperature processable hybrid semiconductor materials with exceptional performances that are revolutionizing the field of optoelectronic devices. Despite their great potential, commercial deployment is hindered by MHPs lack of stability and durability, mainly attributed to ion migration and chemical interactions with the electrodes. To address these issues, 2D layered MHPs are investigated as possible device interlayers or active material substitutes. Here, the 2D perovskite (PEA)2PbBr4 is considered that is recently discussed as promising candidate for X‐ray direct detection. While the increased resilience of (PEA)2PbBr4 radiation detectors has already been reported, the physical mechanisms responsible for such improvement compared to 3D perovskites are not still fully understood. To unravel the charge transport process in (PEA)2PbBr4 crystals thought to underly the device better performance, an investigation technique is adapted previously used on highly resistive inorganic semiconductors, called photo induced current transient spectroscopy (PICTS). It is demonstrated that PICTS can reliably detect three trap states (T1, T2, and T3), and that their evolution upon X‐ray exposure can explain (PEA)2PbBr4 superior radiation tolerance and reduced aging effects. Overall, the results provide essential insights into the electrical characteristics of 2D perovskites and their potential application as reliable direct X‐ray detectors.
Cyclic Atomic Layer Etching of PdSe2
Authors: Kang Ji Eun , Choi Seung Yup , Han Hye Won , Kim Ji Min , Kim Ye Eun , Seok Hyunho , Kim Taesung , Kim Doo San , Yeom Geun Young
Published: September 2024

The unique characteristic of 2D transition‐metal dichalcogenide (TMD) semiconductor materials such as PdSe2 is the ability of the bandgap to vary on the basis of the number of layers present. This variation results in a broad bandgap range spanning from semi‐metallic to semiconducting materials, underscoring the significance of precisely controlling the material thickness. In this study, the thicknesses of chemical vapor deposited PdSe2 films are precisely controlled layer‐by‐layer via cyclic atomic layer etching (ALE), which comprised a radical adsorption step generated by oxygen and chlorine plasmas, followed by a desorption step with an organic solvent vapor such as formic acid. Cyclic etching with one monolayer of PdSe2/cycle is achieved using both types of adsorption gases while maintaining the ratio of Se/Pd underlying PdSe2 at ≈2. This cyclic ALE method is also applicable for smoothing TMD material surfaces by isotropically removing individual rough surface layers. Because this etching method only utilizes chemical reactions with radicals generated by plasmas and organic vapors, it is not only unaffected by the physical damage caused by the irradiation of energetic particles such as ions in plasmas, but also is applicable to 3D structure processing.
Increased Static Charge‐Induced Threshold Voltage Shifts and Memristor Activity in Pentacene OFETs Comprising Polystyrene‐Based Gate Dielectrics Containing Electroactive Small Molecule Crystallites
Authors: Bond Christopher R. , Reich Daniel H. , Katz Howard E.
Published: September 2024

Top‐contact bottom‐gate pentacene OFETs are fabricated with single layer dielectrics comprised of either polystyrene (PS), poly(4‐methylstyrene) (P4MS), or poly(4‐tert‐butylstyrene) (P4TBS). The polystyrenes are blended with varying concentrations of two different small molecules, dibenzotetrathiafulvalene (DBTTF) and 2,8‐difluoro‐5,11‐bis(triethylsilylethynyl)anthradithiophene (diF‐TES‐ADT), to form small, separated crystallites contained throughout the polymer dielectric layer. The OFET characteristics of these devices are investigated and their threshold voltage shifts are measured after −70 V static charging for 5 min. Two‐terminal measurements are conducted using multiple different gate biases in the range of −50 to +50 V to investigate memristor behavior in the devices. OFETs containing DBTTF exhibited ΔVth increases as large as 330% relative to control OFETs containing no DBTTF, while OFETs containing at least 7.5 wt.% DBTTF exhibited memristor activity, with currents ranging from 20 nA to 44 µA depending on the applied bias. This work demonstrates that including small, separated crystallites in polymer dielectrics enhances their charge storage ability and can be promising for creating nonbinary memory devices for data processing. Additionally, the observed memristor activity indicates the OFETs in this work can be used in development of neuromorphic systems that aim to mimic the synaptic behavior of the human nervous system.
Electrostatic Interactions Dominate the Surface Assembly of Silicon‐Based Nanospheres on Carbon Nanofibers for Flexible Lithium‐Ion Batteries
Authors: Jiang Miaomiao , Luo Hongxia , Chen Junliang , Chen Lei , Jiang Wan , Yang Jianping
Published: September 2024

The construction of flexible freestanding silicon‐based electrodes eliminates the addition of inactive materials, improving the overall energy density, and effectively avoiding the disadvantage of active materials being easily separated from the collector due to the volume effect. However, many reports of flexible freestanding electrodes lack long‐term cycling stability. Here, 3 different silicon‐based freestanding electrodes are designed and find that the freestanding electrode with surface assembly dominated by electrostatic interactions can significantly improve long‐term cycling stability. Owing to better mechanical properties, this surface‐assembled electrode demonstrates unique flexibility. The conductive framework and unique void structure not only reveal the excellent lithium‐ion diffusion capability and charge‐transfer kinetics but also provide ample space for the volume expansion of the silicon‐based material, which endows electrodes with excellent electrochemical performance. With 2 folds, the capacity remains at 471 mA h g−1 after 1000 cycles (0.5 A g−1). In addition, the as‐prepared flexible pouch cell maintains high capacity and cycling stability after folding, with an average capacity degradation of only 0.01% per cycle during 1000 cycles, highlighting its considerable potential in the development of flexible devices. Remarkably, such interfacial assembly on the fiber surface also enables the modulation of multilayer assembly.
Synergistic Pd‐Au Catalyst for Selective Electrosynthesis of Dimethyl Carbonate in Conjunction with High‐Rate Redox System
Authors: Fujinuma Naohiro , Page Natalie , Boddy Anna G , Rivkind Joshua , Tomlinson Lindsey , Hoy Erik P , Lofland Samuel E
Published: September 2024

This study reports ambient electrosynthesis of dimethyl carbonate with a palladium–gold catalyst. Material screening identifies a region of intermediate‐catalyst binding energy that facilitates interfacial electron and proton transfers for selective carbonylation, achieving a distinct maximum of 92% faradaic efficiency to dimethyl carbonate. Structural and electrochemical analyses suggest that the alloying of palladium and gold effectively modulates the CO* binding energy to the catalytic surface, in accord with subsequent computational studies. With an extended heterogeneous–homogeneous catalytic environment with a halide redox mediator, a remarkable partial current density of 52 mA cm−2 is observed for dimethyl carbonate for 100 h of continuous operation.
Modulating the Li‐Ion Transport Pathway of Succinonitrile‐Based Plastic Crystalline Electrolytes for Solid‐State Lithium Metal Batteries
Authors: Ye Xue , Fu Han , Zhang Yixiao , Wu Dazhuan , Zhong Yu , Wang Xiuli , Ouyang Xiaoping , Tu Jiangping
Published: September 2024

Succinonitrile (SCN) based plastic crystal electrolytes (SPCEs) have attracted much attention for lithium metal batteries due to their considerable ionic conductivity and thermal stability. Insufficient mechanical properties, weak reductive stability, and the presence of free SCN molecules can result in adverse interfacial reactions. Polymer introduction has been explored to address these challenges. However, the introduction of polymer affects the SCN state, leading to reduced ionic conductivity, potentially due to limited segmental motion of the polymer at room temperature. Herein, a cross‐linked network polymer strategy is proposed to modify the Li‐ion transport pathway in SPCE, aiming to significantly improve the ionic conductivity. The strong interaction between the polymer matrix and SCN enhances their mutual solubility, reduces the crystallinity of SCN, and forms a rapid conduction pathway (polymer—[SCN—Li+]). The ionic conductivity of SPCE increases to 1.28 mS cm−1, with the Li‐ion migration number (tLi+
) also rising to 0.7. Electrochemical performances in Li symmetrical, Li||LiFePO4 and Li||LiNi0.8Co0.1Mn0.1O2 cells show significant improvement at both room temperature and 0 °C. These findings suggest that designing polymer network structures in SPCEs holds promise for solid‐state lithium metal battery applications.
Potassium Diffusion in Mono‐ and Bi‐Crystalline SrTiO3 – Mechanisms and Activation Energies
Authors: Bernzen Janek , Fuchs Carmen , Jacob Timo , Ma Qian , Meyer Tobias , Jooss Christian , Weitzel Karl‐Michael
Published: September 2024

The diffusion of potassium in SrTiO3 (STO) single crystals is investigated as a function of temperature. Charge attachment induced transport experiments are employed inducing diffusion profiles in STO evolving with time. Potassium concentration profiles, characterized ex‐situ by ToF‐SIMS depth profiling, exhibited a bimodal shape indicating two different transport pathways. Two diffusion coefficients are obtained for the two profiles. Their temperature dependence is described using an Arrhenius approach, allowing two activation energies to be derived from the data set. Utilizing DFT+U, the ionic mobility of potassium along the crystal structure is simulated and activation energies are determined for every trajectory. The transport pathway with the larger diffusion coefficient is assigned to defect transport, most likely via Sr vacancies. The transport pathway exhibiting the lower diffusion coefficient is assigned to interstitial transport. In addition, the experiment is repeated on a bicrystalline STO sample to investigate the effect of a grain boundary on the ionic conductivity of the sample. As expected, the grain boundary represents an additional diffusion path for the potassium ions. The corresponding diffusion coefficient along the grain boundary is three orders of magnitude larger than that for bulk diffusion. Atomically resolved structural information in the grain boundary region is presented.
Copper‐Catalyzed Cross Coupling Reaction of Alkyl Bromides with (DMPU)2Zn(Rf)2 Reagent: A Method for the Synthesis of Perfluoroalkylated Compounds
Authors: Liu Bosheng , Jiang Xujuan , Song Yanshan , Liu Shiwen , Xiong Xiaodong , Zeng Xiaojun
Published: September 2024

A method for the copper‐catalyzed cross‐coupling of alkyl bromides with a range of (DMPU)2Zn(Rf)2 reagents has been developed. This protocol tolerates multiple functional groups and provides broad access to aliphatic perfluoroalkylated compounds. The applicability of this procedure is demonstrated in the late‐stage functionalization of drug analogues.
Heterovalent State and Oxygen Vacancy Defect Structure‐Associated V/S Co‐Doped SnO2 for Catalytic Reduction of Organic and Cr6+ Pollutants in the Dark
Authors: Yang Baoqian , Wu Xinru , Su Zhengjie , Insua Benjamin Kunkadma , Zhang Pengkun , Kuo Dong‐Hau , Gao Lulu , Bao Xinde , Lu Dongfang , Lin Jinguo , Chen Xiaoyun
Published: September 2024

V/S co‐doped SnO2 bimetal sulfur‐oxides catalysts labeled as (Sn,V)1‐x(S,O)2‐y or (SnVSO) with heterovalent state and oxygen vacancy defect are prepared via a green and facile method. The presence of SnVSO in the heterovalent states of Sn4+/Sn2+ and V5+/V4+ facilitates the rapid transfer of the electrons. It improves the electronic charge lifetime, accelerating the efficiency of the catalytic reduction of pollutants. The V/S co‐doped SnO2 regulates the bandgap energy structure. The hydrazine adjusts the heterovalent metal states to reduce Sn4+ to Sn2+ and V5+ to V4+. Also, it introduces oxygen vacancies to SnVSO to maintain the charge equilibrium and increase the active surface reactive sites, which enhance the catalytic activity. The SnVSO‐3 prepared with 0.4 mL hydrazine exhibits excellent catalytic activity, which wholly reduces 20 ppm of 100 mL methyl orange (MO), rhodamine B (RhB), methylene blue (MB), hexavalent chromium (Cr6+), and 4‐nitrophenol (4‐NP) within 6 min. In addition, the SnVSO‐3 also has good stability after repeated 6 runs with a reduction efficiency of 96.8%. Therefore, the V/S co‐doped SnO2 sulfur oxide catalysts have a promising potential for reducing Cr6+ and organic pollutants.
TRIM56 Modulates YBX1 Degradation to Ameliorate ZBP1‐Mediated Neuronal PANoptosis in Spinal Cord Injury
Authors: Lou Junsheng , Mao Yiting , Jiang Wu , Shen Honghao , Fan Yunpeng , Yu Qing , Zhou Conghui , Wei Ziyao , Zhou Kailiang , Jin Mengran , Wu Junsong
Published: September 2024

Spinal cord injury (SCI) is a severe injury to the central nervous system, and its treatment is always a major medical challenge. Proinflammatory cell death is considered an important factor affecting neuroinflammation and the prognosis after injury. PANoptosis, a newly discovered type of proinflammatory cell death, regulates the activation of executioner molecules of apoptosis, pyroptosis and necroptosis through the PANoptosome, providing a new target for therapeutic intervention after SCI. However, its role and regulatory mechanism in SCI are not yet elucidated. Here, based on proteomic data, YBX1 expression is significantly increased in neurons after SCI. Guided by RIP‐seq, subsequent experiments reveal that YBX1 promotes ZBP1 expression by stabilizing the Zbp1 mRNA, thereby aggravating ZBP1‐mediated PANoptosis. Furthermore, the E3 ubiquitin ligase TRIM56 is identified as an endogenous inhibitor of YBX1 via molecular docking and IP/MS analysis. Mechanistically, TRIM56 bound to YBX1 and promoted its ubiquitination, thereby accelerating its degradation. Taken together, these findings reveal a novel function of YBX1 in regulating ZBP1‐mediated PANoptosis in the pathogenesis of SCI and verified that TRIM56 functions as an endogenous inhibitor to promote the ubiquitin‐proteasomal degradation of YBX1, providing new insights into SCI treatment strategies.
Breast Tumor Diagnosis Based on Molecular Learning Vector Quantization Neural Networks
Authors: Huang Chun , Shao Jiaying , Peng Baolei , Guo Qingshuang , Li Panlong , Sun Junwei , Wang Yanfeng
Published: September 2024

DNA nanotechnology plays a crucial role in precise cancer medicine. Currently, molecular logic circuits are applied to detect tumor‐specific biomarkers and control the release of therapeutic drugs. However, these systems lack self‐learning capabilities for intelligent diagnostics in biological samples, and their data processing capabilities are limited. Here, a molecular learning vector quantization neural network (LVQNN) model based on DNA strand displacement (DSD) technology for breast tumor diagnosis is developed. Compared to previous work, the molecular LVQNN boasts powerful computing abilities, handling high‐dimensional data for intelligent cancer diagnosis. To verify the feasibility and versatility of the network, two distinct typical datasets are selected: one from a single source with cell morphology data from 569 cases, and a more extensive one spanning different populations and ages, with miRNA gene expression data from 1881 cases. By using the molecular LVQNN, diagnostic experiments are conducted on 50 and 120 public individuals from these two datasets, respectively, achieving accuracy rates of 94% and 97.5%. This study demonstrates that the LVQNN model exhibits significant advantages in breast cancer diagnosis and enhances diagnostic accuracy while introducing new approaches for intelligent cancer diagnosis, anticipated to bring significant breakthroughs and application prospects to precise cancer medicine.
Formation of Conjugated Polymer Monolayer Networks on Water Surface and Nonlinear Charge Transport
Authors: Ishizaki‐Betchaku Yuya , Hara Naoki , Matsuda Taikai , Matsui Jun , Seki Takahiro , Nagano Shusaku
Published: September 2024

Material‐networked conduction paths provide nonlinear electronic properties, which are essential components of computing and physically mimic the brain. In this study, the formation of conjugated polymer monolayer networks and their nonlinear charge transport is demonstrated. Poly(3‐hexylthiophene) (P3HT) monolayer networks doped with 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F4TCNQ) is fabricated using the co‐spread method with an amphiphilic liquid crystal molecule at the air–water interface. Atomic force microscopy and Ultraviolet–visible–near‐infrared absorption spectroscopy measurements reveal the network surface morphologies and doped electronic states. The correlation between the nonlinear electronic characteristics and network structures of the P3HT/F4TCNQ monolayer networks is further systematically investigated through current–voltage and voltage–time measurements for various doping levels, network densities, and numbers of transferred layers. The current–voltage characteristics of the P3HT/F4TCNQ monolayer network device with a simple two‐terminal structure exhibit nonlinear and ohmic conduction behavior, which depend strongly on the network density and geometric dimension (number of transferred layers). It is concluded that the nonlinear properties arise from the limited and unique network of 2D conduction passes. This study highlights the unique features of conducting polymer monolayer networks, paving the way for neuromorphic device applications including conjugated semiconducting polymer‐based material reservoirs with controllable nanostructures.
Recent Research on the Human Biology of Pastoralists
Authors: Campbell Benjamin
Published: September 2024

Despite encroachment by agricultural systems and globalization, pastoral nomads maintain a robust presence in terms of numbers and subsistence activity. At the same time, increasing concern about climate change has promoted awareness that increased climatic fluctuation may push pastoral population past their capacity for resilience. The response of pastoralists to climate change has important implications for our evolutionary past and our increasingly problematic future. Yet, pastoralists have received less explicit attention than foragers as populations under consistent selective constraints including limited caloric intake, high levels of habitual activity, and high disease burdens. Additional factors include exposure to cold and high temperatures, as well as high altitude. Over the last 20 or so years, the use of new techniques for measuring energetics, including actigraphs and doubly labeled water have built on existing noninvasive sample collection for hormones, immune markers and genes to provide a more detailed picture of the human biology of pastoral populations. Here I consider recent work on pastoralists from Siberia and northern Europe, Africa, Asia, and South America. I survey what is known about maternal milk composition and infant health, childhood growth, lactase persistence, and adult energy expenditure and lactase persistence to build a picture of the pastoralist biological response to environmental conditions, including heat, cold, and high altitude. Where available I include information about population history because of its importance for selection. I end by outlining the impact of milk consumption and climate over the human life cycle and make suggestions for further research.