bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and Synthesis of Nitrogen‐Rich Azo‐Bridged Furoxanylazoles as High‐Performance Energetic Materials
Authors: Larin Alexander A. , Shaferov Alexander V. , Kulikov Alexander S. , Pivkina Alla N. , Monogarov Konstantin A. , Dmitrienko Artem O. , Ananyev Ivan V. , Khakimov Dmitry V. , Fershtat Leonid L. , Makhova Nina N.
Published: July 2021

A series of novel energetic materials comprising of azo‐bridged furoxanylazoles enriched with energetic functionalities was designed and synthesized. These high‐energy materials were thoroughly characterized by IR and multinuclear NMR (1H, 13C, 14N) spectroscopy, high‐resolution mass spectrometry, elemental analysis, and differential scanning calorimetry (DSC). The molecular structures of representative amino and azo oxadiazole assemblies were additionally confirmed by single‐crystal X‐ray diffraction and X‐ray powder diffraction. A comparison of contributions of explosophoric moieties into the density of energetic materials revealed that furoxan and 1,2,4‐oxadiazole rings are the densest motifs while the substitution of the azide and amino fragments on the nitro and azo ones leads to an increase of the density. Azo bridged energetic materials have high nitrogen‐oxygen contents (68.8–76.9 %) and high thermal stability. The synthesized compounds exhibit good experimental densities (1.62–1.88 g cm−3), very high enthalpies of formation (846–1720 kJ mol−1), and, as a result, excellent detonation performance (detonation velocities 7.66–9.09 km s−1 and detonation pressures 25.0–37.7 GPa). From the application perspective, the detonation parameters of azo oxadiazole assemblies exceed those of the benchmark explosive RDX, while a combination of high detonation performance and acceptable friction sensitivity of azo(1,2,4‐triazolylfuroxan) make it a promising potential alternative to PETN.
Structure Recovery and Recycling of Used LiCoO2 Cathode Material
Authors: Liang Qian , Yue Haifeng , Zhou Weishan , Wei Qiang , Ru Qiang , Huang Yuan , Lou Hongtao , Chen Fuming , Hou Xianhua
Published: July 2021

A large number of lithium batteries have been retiring from the market of energy storage. Thus, recycling of the used electrode materials is becoming urgent. In this study, an industrial machinery processing was used to recover the crystal structure of the waste LiCoO2 materials with the combination of small‐scale equipment repair technology. The results show that the crystal parameters of the repaired LiCoO2 material become small, the unit cell volume is reduced, and the crystal structure tends to be stable. The Co−O bond length of 1.9134 nm, O−Co−O bond angle of 94.72°, the (003) interplanar spacing of 0.467 nm indicate the excellent recovery level of the repaired LiCoO2. In addition, the electrochemical performance of the repaired LiCoO2 material is greatly improved, compared with the waste material. The capacity of the repaired electrode material can be maintained at 120 mAh g−1 after 100 cycles at the current density of 0.2C. The promising rate performance of the repaired electrode material demonstrates the stable structure. This research work provides a large‐scale method for the direct recovery of LiCoO2 with the reduction of unnecessary energy and reagent consumption, which will be beneficial to the environmental protection.
General, Straightforward, and Atom‐Economical Synthesis of Vinyl Triflimides
Authors: Hao Lei , Pan Qianwen , Zhang Congdi , Wang Sen , Wang Weilin , Zhang Junjie , Bai Lu , Wang Youliang
Published: July 2021

Vinyl triflimides were only accessible recently and their chemistry is yet to be discovered. Herein, we describe a general, straightforward and atom‐economical synthesis of these materials from alkynes and triflimide. A vast array of terminal and internal alkynes with broad spectrum of functionalities could be employed to generate various di‐ and trisubstituted vinyl triflimides regiospecifically with high to specific stereoselectivity. Moreover, the protocol could be conducted on gram scale using terminal and internal alkynes. Preliminarily attempts to probe the unprecedented reactivity of vinyl triflimides revealed part of its chemical properties.
Iron(II)‐Catalyzed Aerobic Biomimetic Oxidation of N‐Heterocycles
Authors: Manna Srimanta , Kong Wei‐Jun , Bäckvall Jan‐E.
Published: July 2021

Herein, an iron(II)‐catalyzed biomimetic oxidation of N‐heterocycles under aerobic conditions is described. The dehydrogenation process, involving several electron‐transfer steps, is inspired by oxidations occurring in the respiratory chain. An environmentally friendly and inexpensive iron catalyst together with a hydroquinone/cobalt Schiff base hybrid catalyst as electron‐transfer mediator were used for the substrate‐selective dehydrogenation reaction of various N‐heterocycles. The method shows a broad substrate scope and delivers important heterocycles in good‐to‐excellent yields.
Preparation of polyvinyl alcohol–chitosan–NH4Br catalyst and its application to cycloaddition of carbon dioxide to propylene oxide
Authors: Kim Hak‐Min , Oh Kyeongseok , Kyung Daeseung , Ahn Han‐geun , Yoon Inhwan , Kwak Soonjong , Nah In Wook
Published: July 2021

An eco‐friendly polyvinyl alcohol (PVA)–chitosan(CS)–NH4Br catalyst was prepared using a modified solution method. Although the amounts of PVA and CS were fixed, the amount of NH4Br was varied in the range 15–45 wt.%. The catalytic performance of PVA–CS–NH4Br was compared based on the carbonation performance in the presence of single‐component catalysts (PVA, CS, and NH4Br) and dual component catalyst (PVA–CS). The catalytic activity of PVA–CS was inadequate and considerably less than that observed when either PVA or CS was exclusively loaded. The number of functional groups within the PVA–CS structure was presumed to have been reduced due to the interactions of the OH groups in PVA and CS. However, the PVA–CS–NH4Br catalyst distinctively exhibited its catalytic performance. It has been suggested that NH4Br aided in sustaining the innate functional groups that both PVA and CS have within the PVA–CS–NH4Br structure. These results indicate that the functional groups and nucleophiles within the PVA–CS–NH4Br structure more effectively participated in the carbonation of propylene oxide. Quantitatively, the addition of 30 wt.% NH4Br yielded the best performance. Characteristic analyses of the catalysts were performed using X‐ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, and X‐ray photoelectron spectroscopy.
Avoiding prior–data conflict in regression models via mixture priors
Authors: Egidi Leonardo , Pauli Francesco , Torelli Nicola
Published: July 2021

The Bayesian‐80 model consists of the prior–likelihood pair. A prior–data conflict arises whenever the prior allocates most of its mass to regions of the parameter space where the likelihood is relatively low. Once a prior–data conflict is diagnosed, what to do next is a hard question to answer. We propose an automatic prior elicitation that involves a two‐component mixture of a diffuse and an informative prior distribution that favours the first component if a conflict emerges. Using various examples, we show that these mixture priors can be useful in regression models as a device for regularizing the estimates and retrieving useful inferential conclusions.
Arnold Diffusion, Quantitative Estimates, and Stochastic Behavior in the Three‐Body Problem
Authors: Capiński Maciej J. , Gidea Marian
Published: July 2021

We consider a class of autonomous Hamiltonian systems subject to small, time‐periodic perturbations. When the perturbation parameter is set to zero, the energy of the system is preserved. This is no longer the case when the perturbation parameter is non‐zero.

We describe a topological method to establish orbits which diffuse in energy for every suitably small perturbation parameter . The method yields quantitative estimates:

the existence of orbits along which the energy drifts by an amount independent of ε; the time required by such orbits to drift is ;

the existence of orbits along which the energy makes chaotic excursions;

explicit estimates for the Hausdorff dimension of the set of such chaotic orbits;

the existence of orbits along which the time evolution of energy approaches a stopped diffusion process (Brownian motion with drift), as ε tends to 0. For each ε fixed, the set of initial conditions of the orbits that yield the diffusion process has positive Lebesgue measure, and in the limit the measure of these sets approaches 0. Moreover, we can obtain any desired values of the drift and variance for the limiting Brownian motion for appropriate sets of initial conditions.

A key feature of our topological method is that it can be implemented in computer‐assisted proofs. We give an application to a concrete model of the planar elliptic restricted three‐body problem, on the motion of an infinitesimal body relative to the Neptune‐Triton system. © 2021 The Authors. Communications on Pure and Applied Mathematics published by Wiley Periodicals LLC.
A novel visualization approach for data provenance
Authors: Yazici Ilkay Melek , Aktas Mehmet S.
Published: July 2021

Data provenance has led to a developing need for the technologies to empower end‐users to assess and take action on the data life cycle. In the Big Data era, companies' amount of data over the world increases each day. As data increases, metadata on the data origin and lifecycle of data also overgrows. Thus, this requires innovations that can provide a better understanding and interpretation of data using data provenance. This study addresses the challenge of extracting data in the form of graphs from scientific workflows and facilitating demanded visualization approaches such as graph comparison, summarization, backward‐forward querying, and stream data visualization. W3C‐PROV‐O provenance specification is implemented via a visualization tool to assess the applicability of proposed algorithms. The proposed algorithms are tested on a large‐scale provenance dataset to explore their performance. In addition, this study discusses the details of a comprehensive usability study of the prototype visualization tool. Results indicate that proposed visualization approaches are usable and processing overhead is insignificant.
Coping with cold: Sorghum cold stress from germination to maturity
Authors: Casto Anna L. , Murphy Katherine M. , Gehan Malia A.
Published: July 2021

Sorghum [Sorghum bicolor (L.) Moench] is an important crop that is highly drought tolerant but susceptible to low temperatures. Many studies have begun to explore the genetic basis of variation in chilling sensitivity in the sorghum germplasm in an effort to improve sorghum's chilling tolerance. However, differences in genetic maps and updates to the sorghum reference genome have made comparing studies of chilling in sorghum challenging. Here, we review the current state of research on chilling tolerance and susceptibility in sorghum during germination and emergence, vegetative growth, and reproduction and harvest stages. Using the most recent sorghum reference genome (v3.1), we have standardized the locations of quantitative trait loci and marker‐trait associations for chilling tolerance traits across the literature. This revealed substantial overlap between quantitative trait loci/marker‐trait associations identified for similar traits across studies of different sorghum populations. Chromosomes 2, 3, and 6 contained particularly concentrated regions of markers associated with chilling tolerance traits. Although many studies have uncovered genetic variation for chilling responses in the sorghum germplasm, follow‐up studies are needed to confirm and characterize the molecular mechanisms responsible for variation in chilling tolerance in sorghum. We discuss potential molecular mechanisms for cold stress tolerance based on agreements between studies and address the challenges and opportunities for increasing chilling tolerance in sorghum and other next‐generation crops.
Two‐Dimensional Conjugated Benzo[1,2‐b:4,5‐b′]diselenophene‐Based Copolymer Donor Enables Large Open‐Circuit Voltage and High Efficiency in Selenophene‐based Organic Solar Cells
Authors: Liu Yan‐Qiang , Zhi Hong‐Fu , Bai Hai‐Rui , Jiang Zhao , Wan Shi‐Sheng , Jiang Mengyun , Mahmood Asif , Yang Can , Sun Shuo , An Qiaoshi , Wang Jin‐Liang
Published: July 2021

A two‐dimensional electron‐rich fused‐ring moiety (ClBDSe) based on benzo[1,2‐b:4,5‐b′]diselenophene is synthesized. Three copolymers (PBDT−Se, PBDSe−T, and PBDSe−Se) are obtained by manipulating the connection types and number of selenophene units on the conjugated main chains with two 2D fused‐ring units and two different π‐bridges, respectively. In comparison with PBDT−Se and PBDSe−Se, PBDSe−T with benzo[1,2‐b:4,5‐b′]diselenophene unit and thiophene π‐bridge exhibits the deepest HOMO energy level and the strongest crystallinity in neat films. The PBDSe−T:Y6 blend film exhibits the best absorption complementarity, the most distinctive face‐on orientation with proper phase separation, the highest carrier mobilities, and the lowest charge recombination among three blend films. Finally, the PBDSe−T:Y6‐based device delivers an impressive power conversion efficiency (PCE) of 14.50 %, which is higher than those of PBDT−Se:Y6 and PBDSe−Se:Y6. Moreover, a decent open‐circuit voltage (Voc) of 0.89 V with a remarkably small energy loss of 0.44 eV is achieved for PBDSe−T:Y6. The efficiency of 14.50 % is the highest value for selenophene‐containing copolymer‐based binary organic solar cells (OSCs). This study provides evidence that introduction of 2D‐benzo[1,2‐b:4,5‐b′]diselenophene as a fused electron‐rich unit with π‐bridging into copolymeric donors is a valid strategy for providing high Voc and excellent PCE simultaneously in selenophene‐based OSCs.
Thiol‐Amine‐Based Solution Processing of Cu2S Thin Films for Photoelectrochemical Water Splitting
Authors: Zhang Xi , Yang Wooseok , Niu Wenzhe , Adams Pardis , Siol Sebastian , Wang Zhenbin , Tilley S. David
Published: July 2021

Cu2S is a promising solar energy conversion material owing to its good optical properties, elemental earth abundance, and low cost. However, simple and cheap methods to prepare phase‐pure and photo‐active Cu2S thin films are lacking. This study concerns the development of a cost‐effective and high‐throughput method that consists of dissolving high‐purity commercial Cu2S powder in a thiol‐amine solvent mixture followed by spin coating and low‐temperature annealing to obtain phase‐pure crystalline low chalcocite Cu2S thin films. After coupling with a CdS buffer layer, a TiO2 protective layer and a RuOx hydrogen evolution catalyst, the champion Cu2S photocathode gives a photocurrent density of 2.5 mA cm−2 at −0.3 V vs. reversible hydrogen electrode (VRHE), an onset potential of 0.42 VRHE, and high stability over 12 h in pH 7 buffer solution under AM1.5 G simulated sunlight illumination (100 mW cm−2). This is the first thiol‐amine‐based ink deposition strategy to prepare phase‐pure Cu2S thin films achieving decent photoelectrochemical performance, which will facilitate its future scalable application for solar‐driven hydrogen fuel production.
BER analysis of truncated SVD‐based MU‐MIMO ZF detection scheme under correlated Rayleigh fading channel
Authors: Eduru Supraja , Rangaswamy Nakkeeran
Published: July 2021

In multi‐user multiple input multiple output (MU‐MIMO) uplink, the bit error rate (BER) of linear detection schemes, namely, zero forcing (ZF) and minimum mean square error (MMSE) under correlated Rayleigh fading channel deteriorates with increase in spatial correlation and load factor due to the increase in the condition number of the channel matrix. Moreover, the performance gap between ZF and MMSE increases with increase in the antenna number for large load factors. To address this issue, in this paper, truncated singular value decomposition (TSVD), which is a popular method for solving ill‐posed problem, is used in the ZF detection process through proper selection of hard threshold. However, the pseudo‐inverse computed using TSVD is an approximate inverse, which results in interference at the output of the detection process. Therefore, a mathematical expression for the post‐processing signal‐to‐interference‐plus‐noise ratio (SINR) of the substream is derived and subsequently BER is evaluated. Further, the analytical BER is analyzed with respect to the parameters namely, average signal‐to‐noise ratio (SNR) (
), correlation coefficient (
), load factor (
), and number of singular values considered to compute the hard threshold (
) and also validated by Monte Carlo trails. From the simulation results, it is observed that for higher order MU‐MIMO systems and at lower values of
, the performance of TSVD‐based scheme is comparable with that of MMSE by decreasing the truncation parameter (
). Moreover, as the complexity of TSVD‐based ZF using randomized schemes is
), therefore, the complexity of detection significantly decreases with decrease in
.
Postembryonic development and aging of the appendicular skeleton in Ambystoma mexicanum
Authors: Riquelme‐Guzmán Camilo , Schuez Maritta , Böhm Alexander , Knapp Dunja , Edwards‐Jorquera Sandra , Ceccarelli Alberto S. , Chara Osvaldo , Rauner Martina , Sandoval‐Guzmán Tatiana
Published: July 2021

Background

The axolotl is a key model to study appendicular regeneration. The limb complexity resembles that of humans in structure and tissue components; however, axolotl limbs develop postembryonically. In this work, we evaluated the postembryonic development of the appendicular skeleton and its changes with aging.

Results

The juvenile limb skeleton is formed mostly by Sox9/Col1a2 cartilage cells. Ossification of the appendicular skeleton starts when animals reach a length of 10 cm, and cartilage cells are replaced by a primary ossification center, consisting of cortical bone and an adipocyte‐filled marrow cavity. Vascularization is associated with the ossification center and the marrow cavity formation. We identified the contribution of Col1a2‐descendants to bone and adipocytes. Moreover, ossification progresses with age toward the epiphyses of long bones. Axolotls are neotenic salamanders, and still ossification remains responsive to l‐thyroxine, increasing the rate of bone formation.

Conclusions

In axolotls, bone maturation is a continuous process that extends throughout their life. Ossification of the appendicular bones is slow and continues until the complete element is ossified. The cellular components of the appendicular skeleton change accordingly during ossification, creating a heterogenous landscape in each element. The continuous maturation of the bone is accompanied by a continuous body growth.
Variable precipitation leads to dynamic range limits of forest songbirds at a forest‐grassland ecotone
Authors: Sinnott Emily A. , Papeş Monica , O’Connell Timothy J.
Published: July 2021

Boundaries between vegetation types, known as ecotones, can be dynamic in response to climatic changes. The North American Great Plains includes a forest‐grassland ecotone in the southcentral United States that has expanded and contracted in recent decades in response to historical periods of drought and pluvial conditions. This dynamic region also marks a western distributional limit for many passerine birds that typically breed in forests of the eastern United States. To better understand the influence that variability can exert on broad‐scale biodiversity, we explored historical longitudinal shifts in the western extent of breeding ranges of eastern forest songbirds in response to the variable climate of the southern Great Plains. We used climatic niche modeling to estimate current distributional limits of nine species of forest‐breeding passerines from 30‐year average climate conditions from 1980 to 2010. During this time, the southern Great Plains experienced an unprecedented wet period without periodic multi‐year droughts that characterized the region's long‐term climate from the early 1900s. Species’ climatic niche models were then projected onto two historical drought periods: 1952–1958 and 1966–1972. Threshold models for each of the three time periods revealed dramatic breeding range contraction and expansion along the forest‐grassland ecotone. Precipitation was the most important climate variable defining breeding ranges of these nine eastern forest songbirds. Range limits extended farther west into southern Great Plains during the more recent pluvial conditions of 1980–2010 and contracted during historical drought periods. An independent dataset from BBS was used to validate 1966–1972 range limit projections. Periods of lower precipitation in the forest‐grassland ecotone are likely responsible for limiting the western extent of eastern forest songbird breeding distributions. Projected increases in temperature and drought conditions in the southern Great Plains associated with climate change may reverse range expansions observed in the past 30 years.
Taxonomic and functional diversity covary in rock pool microalgal communities despite their different drivers
Authors: Aarnio Sonja , Soininen Janne
Published: July 2021

Local biodiversity has traditionally been estimated with taxonomic diversity metrics such as species richness. Recently, the concept of biodiversity has been extended beyond species identity by ecological traits determining the functional role of a species in a community. This interspecific functional diversity typically responds more strongly to local environmental variation compared with taxonomic diversity, while taxonomic diversity may mirror more strongly dispersal processes compared with functional metrics. Several trait‐based indices have been developed to measure functional diversity for various organisms and habitat types, but studies of their applicability on aquatic microbial communities have been underrepresented. We examined the drivers and covariance of taxonomic and functional diversity among diatom rock pool communities on the Baltic Sea coast. We quantified three taxonomic (species richness, Shannon's diversity, and Pielou's evenness) and three functional (functional richness, evenness, and divergence) diversity indices and determined abiotic factors best explaining variation in these indices by generalized linear mixed models. The six diversity indices were highly collinear except functional evenness, which merely correlated significantly with taxonomic evenness. All diversity indices were always explained by water conductivity and temperature–sampling month interaction. Taxonomic diversity was further consistently explained by pool distance to the sea, and functional richness and divergence by pool location. The explained variance in regression models did not markedly differ between taxonomic and functional metrics. Our findings do not clearly support the superiority of neither set of diversity indices in explaining coastal microbial diversity, but rather highlight the general overlap among the indices. However, as individual metrics may be driven by different factors, the greatest advantage in assessing biodiversity is nevertheless probably achieved with a simultaneous application of the taxonomic and functional diversity metrics.
Examining the fluvial alteration hypothesis amidst recovery of the Interior Least Tern (Sternula antillarum)
Authors: Alexander J. S. , Huzurbazar S. , McElroy B. J.
Published: July 2021

The world's large river systems are under increasing stress to support growing populations and economies. Balancing inevitable fluvial alteration with protections of river ecosystems will require awareness of lessons learned in big river systems where system‐scale alterations have already occurred. In 1985, the Interior Least Tern (Sternula antillarum; terns) was listed as endangered, citing “alteration of natural river dynamics” as cause for population declines. We refer to this as the “fluvial alteration hypothesis” and examine it by attempting to answer two primary questions: [Q1] What are the first‐order physical and hydrologic metrics associated with tern nesting reach selection at the regional scale? [Q2] Did human‐induced changes in these metrics differ between regions where tern breeding populations have recovered and where it has been stable or declined? We compiled metrics of sandbar nesting habitat across the nesting region for modern conditions and used regression modeling to assess the relative effects of each metric on nesting reach selection. At the scale of a nesting region, terns selected for nesting reaches that are wider have greater potential to braid, and are less likely to flood during nesting season. A comparison between subregions indicates that modern tern nesting conditions are substantially better in the lower Mississippi River and tributaries (LMRT) systems than the Missouri River and tributaries (MORT) system. However, both subregions had nearly equivalent sandbar nesting habitat quality prior to major human modifications. The fluvial alteration hypothesis was consistent with geomorphic assessments for the MORT system, but overlooked potential for human alterations to have differing, even beneficial effects to tern nesting habitat in the LMRT system.
Transcriptional and posttranslational regulation of Th17/Treg balance in health and disease
Authors: Zhang Weiqi , Liu Xu , Zhu Yicheng , Liu Xinnan , Gu Yunting , Dai Xueyu , Li Bin
Published: July 2021

Regulatory T (Treg) cells and T helper type 17 (Th17) cells play important roles in adaptive immune responses, antagonizing each other in immune disorders. Th17/Treg balance is critical to maintaining the immune homeostasis of human bodies and is tightly regulated under healthy conditions. The transcription factors that are required for driving Th17 and Treg cell lineages differentiation respectively, RORγt and FOXP3 are tightly regulated under different tissue microenvironment, especially the transcriptional induction, posttranslational modifications, and dynamic enzymatic cofactors binding. The imbalance caused by alteration of the quantity or properties of RORγt+ Th17 or FOXP3+ Treg can contribute to inflammatory disorders in humans. Restoring Th17/Treg balance by modifying the enzymatic activities of RORγt and FOXP3 binding partners may be therapeutically applied to treat severe immune disorders. In this review, we focus on the transcriptional and posttranslational regulations of Th17/Treg balance, immune disorders caused by Th17/Treg imbalance, and new therapeutic strategies for restoring immune homeostasis.
Mutant B2M‐HLA‐E and B2M‐HLA‐G fusion proteins protects universal chimeric antigen receptor‐modified T cells from allogeneic NK cell‐mediated lysis
Authors: Guo Yelei , Xu Beilei , Wu Zhiqiang , Bo Jian , Tong Chuan , Chen Deyun , Wang Jin , Wang Haoyi , Wang Yao , Han Weidong
Published: July 2021

Recent studies have indicated the antitumor activity and reduced allogeneic response of universal chimeric antigen receptor‐modified T (UCAR T) cells lacking endogenous T cell receptors and beta‐2 microglobulin (B2M) generated using gene‐editing technologies. However, these cells are vulnerable to lysis by allogeneic natural killer (NK) cells due to their lack of human leukocyte antigen (HLA) class I molecule expression. Here, constitutive expression of mutant B2M‐HLA‐E (mBE) and B2M‐HLA‐G (mBG) fusion proteins in anti‐CD19 UCAR T (UCAR T‐19) cells was conducted to protect against allogeneic NK cell‐mediated lysis. The ability of cells expressing mBE or mBG to resist NK cell‐mediated lysis was observed in gene‐edited Jurkat CAR19 cells. UCAR T‐19 cells constitutively expressing the mBE and mBG fusion proteins were manufactured and showed effective and specific anti‐tumor activity. Constitutive expression of the mBE and mBG fusion proteins in UCAR T‐19 cells prevented allogeneic NK cell‐mediated lysis. In addition, these cells were not recognizable by allogeneic T cells. Additional experiments, including those in animal models and clinical trials, are required to evaluate the safety and efficacy of UCAR T‐19 cells that constitutively express mBE and mBG.
A conserved pathway of transdifferentiation in murine Kupffer cells
Authors: Li Xinyu , Hollingshead Nicole , Lampert Sarah , Truong Camtu D. , Li Wanyu , Niu Junqi , Crispe Ian N. , Soysa Radika
Published: July 2021

Abundant long‐lived liver‐resident macrophages, termed Kupffer cells, are activated during chronic liver injury. They secrete both pro‐inflammatory and pro‐fibrotic cytokines, which act on hepatic stellate cells causing their transdifferentiation into myofibroblasts that deposit collagen. In other tissues, wound‐associated macrophages go further, and transdifferentiate into fibrocytes, secreting collagen themselves. We tested Kupffer cells for this property in two experimental models: mixed non‐parenchymal cell culture, and precision‐cut liver slice culture. Using the Emr1‐Cre transgene as a driver and the RiboTag transgene as a reporter, we found that Kupffer cells undergo transdifferentiation under these circumstances. Over time, they lose the expression of both Kupffer cell‐specific and macrophage‐specific genes and the transcription factors that control their expression, and they begin to express multiple genes and proteins characteristic of either myofibroblasts or tissue fibroblasts. These effects were strongly conserved between non‐parenchymal cell culture and liver tissue slice culture, arguing that such transdifferentiation is a conserved function of Kupffer cells. We conclude that in addition to supporting fibrosis through an action on stellate cells, Kupffer cells also participate in liver fibrosis through transdifferentiation into fibrocytes.
Human herpesvirus 6 and epilepsy
Authors: Theodore William H. , Leibovitch Emily , Billioux Bridgette J. , Inati Sara K. , Zaghloul Kareem , Heiss John , Gaillard William D. , Jacobson Steven
Published: July 2021

We investigated the association between human herpesvirus 6 (HHV‐6) and mesial temporal sclerosis (MTS) in 87 patients who had surgery for drug‐resistant epilepsy. Fifty‐four had MTS, 22 focal cortical dysplasia (FCD), four tumors, three vascular malformations, and three a history of encephalitis. We extracted DNA from fresh brain tissue immediately after surgery and performed viral detection with quantitative real‐time polymerase chain reaction (PCR) or digital droplet PCR specific for HHV‐6A and HHV‐6B. Tissue was studied with standard clinical techniques, including hematoxylin and eosin, glial fibrillary acidic protein, and NeuN stains. Twenty‐nine of 54 patients with MTS, six of 23 with focal cortical dysplasia (FCD), and one of three with a history of encephalitis were positive for HHV‐6 (P < .02). Febrile seizure history was not associated with HHV‐6 detection. Patients with MTS had significantly lower seizure onset age than those with other pathologies. Thirteen patients had positron emission tomography with [11C]PBR28, a marker for reactive astrocytes and activated microglia; there was a trend for HHV‐6‐positive patients to have higher binding in their seizure foci, suggesting inflammation. Our study supports a potential role for HHV‐6 in the etiology of MTS.
C‐doped SnO2 nanostructure/MoS2/p‐Si electrodes for visible light‐driven photoelectrochemical hydrogen evolution reaction
Authors: Mallikarjuna Koduru , Tekalgne Mahider Asmare , Hasani Amirhossein , Hong Sung Hyun , Ahn Sang Hyun , Kim Soo Young , Kim Haekyoung
Published: July 2021

Recently, the increase in the CO2 content in the Earth's atmosphere causes global warming and the rapid consumption of fossil fuel resources such as coal and oil. Therefore, effort is required to create clean and sustainable energy resources to address these environmental issues. In this context, hydrogen evolution from water splitting‐based photoelectrochemical technologies plays a significant role as a zero CO2 emission fuel. Here, we design and prepare carbon‐doped SnO2 nanostructures by a simple single‐step thermal decomposition method and coated on a MoS2/p‐Si substrate for hydrogen evolution by photoelectrochemical water splitting. The C‐doped SnO2/MoS2/p‐Si shows enhanced activity in the hydrogen evolution reaction, with an onset potential of −0.17 V at 2.73 mA/cm2, and high stability for over 45 hours. In addition, the doping of carbon influences the shape of the nanostructures, inducing their transformation from cubical rods to polyhedral structures. This study provides a promising method for the fabrication of heterogeneous photoelectrocatalysts for overall water splitting.
Sources and Fate of the Antiandrogenic Fluorescent Dye 4-Methyl-7-Diethylaminocoumarin in Small River Systems
Authors: Muschket Matthias , Brack Werner , Inostroza Pedro A. , Beckers Liza-Marie , Schulze Tobias , Krauss Martin
Published: July 2021

Recently, the potent antiandrogen 4-methyl-7-diethylaminocoumarin (C47) and its potential transformation products 4-methyl-7-ethylaminocoumarin (C47T1) and 4-methyl-7-aminocoumarin (C47T2) were identified as novel environmental contaminants. We assessed for the first time the sources, distribution, and fate of these compounds in aquatic systems using the Holtemme River (Saxony-Anhalt, Germany), which is a hotspot for these contaminants. To this end, wastewater-treatment plant (WWTP) influent and effluent samples, surface water samples over 3 years, and the longitudinal profiles in water, sediment, and gammarids were analyzed. From the longitudinal profile of the river stretch, the WWTP of Silstedt was identified as the sole point source for these compounds in the River Holtemme, and exposure concentrations in the low micrograms per liter range could be recorded continuously over 3 years. Analysis of WWTP influent and effluent showed a transformation of approximately half of the C47 into C47T1 and C47T2 but no complete removal. A further attenuation of the three coumarins after discharge into the river could be largely attributed to dilution, while transformation was only approximately 20%, thus suggesting a significant persistence in aquatic systems. Experimentally derived partitioning coefficients between water and sediment organic carbon exceeded those predicted using the OPERA quantitative structure–activity relationship tools and polyparameter linear free-energy relationships by up to 93-fold, suggesting cation binding as a significant factor for their sorption behavior. Near-equilibrium conditions between water and sediment were not observed close to the emitting WWTP but farther downstream in the river. Experimental and predicted bioaccumulation factors for gammarids were closely matching, and the concentrations in field-sampled gammarids were close to steady state with exposure concentrations in the water phase of the river. Environ Toxicol Chem 2021;40:3078–3091. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
Improving the predictive potential of diffusion MRI in schizophrenia using normative models—Towards subject‐level classification
Authors: Elad Doron , Cetin‐Karayumak Suheyla , Zhang Fan , Cho Kang Ik K. , Lyall Amanda E. , Seitz‐Holland Johanna , Ben‐Ari Rami , Pearlson Godfrey D. , Tamminga Carol A. , Sweeney John A. , Clementz Brett A. , Schretlen David J. , Viher Petra Verena , Stegmayer Katharina , Walther Sebastian , Lee Jungsun , Crow Tim J. , James Anthony , Voineskos Aristotle N. , Buchanan Robert W. , Szeszko Philip R. , Malhotra Anil K. , Keshavan Matcheri S. , Shenton Martha E. , Rathi Yogesh , Bouix Sylvain , Sochen Nir , Kubicki Marek R. , Pasternak Ofer
Published: July 2021

Diffusion MRI studies consistently report group differences in white matter between individuals diagnosed with schizophrenia and healthy controls. Nevertheless, the abnormalities found at the group‐level are often not observed at the individual level. Among the different approaches aiming to study white matter abnormalities at the subject level, normative modeling analysis takes a step towards subject‐level predictions by identifying affected brain locations in individual subjects based on extreme deviations from a normative range. Here, we leveraged a large harmonized diffusion MRI dataset from 512 healthy controls and 601 individuals diagnosed with schizophrenia, to study whether normative modeling can improve subject‐level predictions from a binary classifier. To this aim, individual deviations from a normative model of standard (fractional anisotropy) and advanced (free‐water) dMRI measures, were calculated by means of age and sex‐adjusted z‐scores relative to control data, in 18 white matter regions. Even though larger effect sizes are found when testing for group differences in z‐scores than are found with raw values (p < .001), predictions based on summary z‐score measures achieved low predictive power (AUC < 0.63). Instead, we find that combining information from the different white matter tracts, while using multiple imaging measures simultaneously, improves prediction performance (the best predictor achieved AUC = 0.726). Our findings suggest that extreme deviations from a normative model are not optimal features for prediction. However, including the complete distribution of deviations across multiple imaging measures improves prediction, and could aid in subject‐level classification.
Early micro‐ and macrostructure of sensorimotor tracts and development of cerebral palsy in high risk infants
Authors: Chandwani Rahul , Kline Julia E. , Harpster Karen , Tkach Jean , Parikh Nehal A. ,   The Cincinnati Infant Neurodevelopment Early Prediction Study (CINEPS) Group
Published: July 2021

Infants born very preterm (VPT) are at high risk of motor impairments such as cerebral palsy (CP), and diagnosis can take 2 years. Identifying in vivo determinants of CP could facilitate presymptomatic detection and targeted intervention. Our objectives were to derive micro‐ and macrostructural measures of sensorimotor white matter tract integrity from diffusion MRI at term‐equivalent age, and determine their association with early diagnosis of CP. We enrolled 263 VPT infants (≤32 weeks gestational age) as part of a large prospective cohort study. Diffusion and structural MRI were acquired at term. Following consensus guidelines, we defined early diagnosis of CP based on abnormal structural MRI at term and abnormal neuromotor exam at 3–4 months corrected age. Using Constrained Spherical Deconvolution, we derived a white matter fiber orientation distribution (fOD) for subjects, performed probabilistic whole‐brain tractography, and segmented nine sensorimotor tracts of interest. We used the recently developed fixel‐based (FB) analysis to compute fiber density (FD), fiber‐bundle cross‐section (FC), and combined fiber density and cross‐section (FDC) for each tract. Of 223 VPT infants with high‐quality diffusion MRI data, 14 (6.3%) received an early diagnosis of CP. The cohort's mean (SD) gestational age was 29.4 (2.4) weeks and postmenstrual age at MRI scan was 42.8 (1.3) weeks. FD, FC, and FDC for each sensorimotor tract were significantly associated with early CP diagnosis, with and without adjustment for confounders. Measures of sensorimotor tract integrity enhance our understanding of white matter changes that antecede and potentially contribute to the development of CP in VPT infants.
The clinical outcomes of COVID‐19 in HIV‐positive patients: A systematic review of current evidence
Authors: SeyedAlinaghi SeyedAhmad , Karimi Amirali , MohsseniPour Mehrzad , Barzegary Alireza , Mirghaderi Seyed Peyman , Fakhfouri Amirata , Saeidi Solmaz , Razi Armin , Mojdeganlou Hengameh , Tantuoyir Marcarious M. , Afsahi Amir Masoud , Mehraeen Esmaeil , Dadras Omid
Published: July 2021

Introduction

Patients with chronic underlying diseases are more susceptible to coronavirus disease 2019 (COVID‐19) complications. Recent studies showed people living with HIV (PLWH) are not at greater risk than the general population. Few studies have reviewed the impacts of COVID‐19 on PLWH. The purpose of this systematic review was to investigate the impact of COVID‐19 on patients infected with HIV.

Methods

We executed a systematic search using four databases of PubMed, Scopus, Science Direct, and Web of Science and screened the records in two steps based on their title/abstract and full text. This study follows the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) checklist to elevate the validity and reliability of its results.

Results

We reviewed 36 studies. The patients' age was above 20 years in all studies. In almost all studies, the inflammatory parameters were reported high. In most of the studies, all HIV patients completely recovered from the COVID 19 infection. Although CD4 count was not recorded in all studies, the minimum level was reported as 12 cells/µl.

Conclusion

Based on the current review, we concluded that HIV patients at advanced stages (3 or 4) of the disease, whose CD4 counts are low, may show less severe COVID‐19 infection symptoms. Similarly, Interference can reduce the severity of immune reactions and subsequent cytokine storms and consequently mitigate the symptoms. Therefore, in most of the studies, the majority of HIV patients showed no severe symptoms and completely recovered from COVID 19 infection.
Long‐term B cell depletion associates with regeneration of kidney function
Authors: Fleig Susanne V. , Konen Franz F. , Schröder Christoph , Schmitz Jessica , Gingele Stefan , Bräsen Jan H. , Lovric Svjetlana , Schmidt Bernhard M. W. , Haller Hermann , Skripuletz Thomas , von Vietinghoff Sibylle
Published: July 2021

Background

Chronic kidney disease (CKD) is a common condition that increases mortality and the risk of cardiovascular and other morbidities regardless of underlying renal condition. Chronic inflammation promotes renal fibrosis. Recently, renal B cell infiltrates were described in chronic kidney disease of various etiologies beyond autoimmunity.

Methods

We here investigated B cells and indicators of tertiary lymphoid structure formation in human renal biopsies. Renal function was studied during long‐term B cell depletion in human patients with membranous nephropathy and with CKD of unknown origin.

Results

Cytokine profiles of tertiary lymphoid structure formation were detected in human renal interstitium in a range of kidney diseases. Complex B cell structures consistent with tertiary lymphoid organ formation were evident in human membranous nephropathy. Here, B cell density did not significantly associate with proteinuria severity, but with worse excretory renal function. Proteinuria responses mostly occurred within the first 6 months of B cell depletion. In contrast, recovery of excretory kidney function was observed only after 18 months of continuous therapy, consistent with a structural process. Renal tertiary lymphatic structures were also detected in the absence of autoimmune kidney disease. To start to address whether B cell depletion may affect CKD in a broader population, we assessed kidney function in neurologic patients with CKD of unknown origin. In this cohort, eGFR significantly increased within 24 months of B cell depletion.

Conclusion

Long‐term B cell depletion associated with significant improvement of excretory kidney function in human CKD. Kinetics and mechanisms of renal B cell aggregation should be investigated further to stratify the impact of B cells and their aggregates as therapeutic targets.
Differences in the neutrophil/lymphocyte ratio and the platelet/lymphocyte ratio in pregnant women with and without COVID‐19
Authors: Carranza Lira Sebastián , García Espinosa Maritza
Published: July 2021

Objective

To determine the differences in the neutrophil/lymphocyte ratio (NLR) and the platelet/lymphocyte ratio (PLR) in pregnant women with and without COVID‐19.

Methods

Observational, cross‐sectional, retrospective, comparative, open, controlled study done from January to April 2021 at the UMAE Hospital de Gineco Obstetricia “Luis Castelazo Ayala” Instituto Mexicano del Seguro Social. Mexico City, Mexico: Patients were divided into those with a negative test for COVID‐19 and those with a positive test, with the latter then being divided according to disease severity into mild, moderate, and severe groups. In all the NLR and PLR were calculated. Symptoms, vital signs, and oxygen saturation were documented. Statistical analysis: Central tendency and dispersion measures, Kruskal‐Wallis test, Mann‐Whitney U test, and chi‐squared test were used. Sensitivity, specificity, positive predictive value, negative predictive value, and odds ratio (OR) were calculated.

Results

Seventy‐seven patients were included, 24 without COVID‐19 and 53 with COVID‐19. There were 33, 10, and 10 patients in the mild, moderate, and severe disease groups, respectively. There was no difference in NLR between the groups and the PLR was significantly higher in the severe disease group. With a 5.1 NLR cutoff point, between normal and those with severe disease, the sensitivity was 70% and specificity 63%, whilst with a 221 PLR cutoff point, the sensitivity was 90% and the specificity 83% (OR 45, 95% CI 4.40–461.7).

Conclusion

PLR more than NLR was useful to detect pregnant patients with COVID‐19 with severe disease.
Risk‐reducing salpingo‐oophorectomy and breast cancer incidence among Jewish BRCA1/BRCA2‐mutation carriers—an Israeli matched‐pair study
Authors: Perri Tamar , Levin Gabriel , Naor‐Revel Shani , Eliassi‐Revivo Perry , Lifshitz Dror , Friedman Eitan , Korach Jacob
Published: July 2021

Objective

To study the association of risk‐reducing bilateral salpingo‐oophorectomy (RRBSO) and breast cancer risk among BRCA pathogenic sequence variants (PSV).

Methods

Jewish Israeli BRCA carriers who underwent RRBSO were matched with those who did not—by the mutated gene and year of birth (±1 year). Breast cancer rates were compared.

Results

Overall, 127 pairs met the inclusion criteria, 79 (60.6%) pairs harbored BRCA1 PSV and 50 (39.4%) pairs harbored BRCA2 PSV. Median follow up was 8.7 years (interquartile range 4.6–16.1 years). Breast cancer rate for all BRCA carriers combined was not affected by RRBSO (RRBSO 21 [16.5%] versus no RRBSO 31 [24.4%], hazard ratio [HR] for breast cancer 0.61, 95% confidence interval [CI] 0.33–1.14, P = 0.127). No association between RRBSO and breast cancer incidence was noted among BRCA1 PSV carriers. In BRCA2 PSV carriers, RRBSO was associated with a decreased overall breast cancer incidence (HR 0.20, 95% CI 0.44–0.91, P = 0.038), as well as after 5, 10, 15, and 20 years. Hormone replacement therapy was used by 62 PSV carriers, 52 in the RRBSO group and 10 in the no‐RRBSO group and did not affect breast cancer risk (P = 0.463).

Conclusion

RRBSO is associated with breast cancer risk reduction in Jewish Israeli BRCA2 PSV carriers.

Risk‐reducing bilateral salpingo‐oophorectomy was associated with breast cancer risk reduction in Jewish Israeli BRCA2 pathogenic sequence variant carriers.
A novel receptive field‐regularized V‐net and nodule classification network for lung nodule detection
Authors: Dodia Shubham , Basava Annappa , Padukudru Anand Mahesh
Published: July 2021

Recent advancements in deep learning have achieved great success in building a reliable computer‐aided diagnosis (CAD) system. In this work, a novel deep‐learning architecture, named receptive field regularized V‐net (RFR V‐Net), is proposed for detecting lung cancer nodules with reduced false positives (FP). The method uses a receptive regularization on the encoder block's convolution and deconvolution layer of the decoder block in the V‐Net model. Further, nodule classification is performed using a new combination of SqueezeNet and ResNet, named nodule classification network (NCNet). Postprocessing image enhancement is performed on the 2D slice by increasing the image's intensity by adding pseudo‐color or fluorescence contrast. The proposed RFR V‐Net resulted in dice similarity coefficient of 95.01% and intersection over union of 0.83, respectively. The proposed NCNet achieved the sensitivity of 98.38% and FPs/Scan of 2.3 for 3D representations. The proposed NCNet resulted in considerable improvements over existing CAD systems.