The ability to determine the electronic structure of catalysts during electrochemical reactions is highly important for identification of the active sites and the reaction mechanism. Here we ...successfully applied soft X-ray spectroscopy to follow in operando the valence and spin state of the Co ions in Li
Co
O
under oxygen evolution reaction (OER) conditions. We have observed that a substantial fraction of the Co ions undergo a voltage-dependent and time-dependent valence state transition from Co
to Co
accompanied by spontaneous delithiation, whereas the edge-shared Co-O network and spin state of the Co ions remain unchanged. Density functional theory calculations indicate that the highly oxidized Co
site, rather than the Co
site or the oxygen vacancy site, is mainly responsible for the high OER activity.
Objective
To develop and evaluate the performance of U-Net for fully automated localization and segmentation of cervical tumors in magnetic resonance (MR) images and the robustness of extracting ...apparent diffusion coefficient (ADC) radiomics features.
Methods
This retrospective study involved analysis of MR images from 169 patients with cervical cancer stage IB–IVA captured; among them, diffusion-weighted (DW) images from 144 patients were used for training, and another 25 patients were recruited for testing. A U-Net convolutional network was developed to perform automated tumor segmentation. The manually delineated tumor region was used as the ground truth for comparison. Segmentation performance was assessed for various combinations of input sources for training. ADC radiomics were extracted and assessed using Pearson correlation. The reproducibility of the training was also assessed.
Results
Combining b0, b1000, and ADC images as a triple-channel input exhibited the highest learning efficacy in the training phase and had the highest accuracy in the testing dataset, with a dice coefficient of 0.82, sensitivity 0.89, and a positive predicted value 0.92. The first-order ADC radiomics parameters were significantly correlated between the manually contoured and fully automated segmentation methods (
p
< 0.05). Reproducibility between the first and second training iterations was high for the first-order radiomics parameters (intraclass correlation coefficient = 0.70–0.99).
Conclusion
U-Net-based deep learning can perform accurate localization and segmentation of cervical cancer in DW MR images. First-order radiomics features extracted from whole tumor volume demonstrate the potential robustness for longitudinal monitoring of tumor responses in broad clinical settings.
Summary
U-Net-based deep learning can perform accurate localization and segmentation of cervical cancer in DW MR images.
Key Points
•
U-Net-based deep learning can perform accurate fully automated localization and segmentation of cervical cancer in diffusion-weighted MR images.
•
Combining b0, b1000, and apparent diffusion coefficient (ADC) images exhibited the highest accuracy in fully automated localization.
• First-order radiomics feature extraction from whole tumor volume was robust and could thus potentially be used for longitudinal monitoring of treatment responses.
Purpose
We aimed to evaluate the validity of cancer diagnosis in the National Health Insurance (NHI) database, which has routinely collected the health information of almost the entire Taiwanese ...population since 1995, compared with the Taiwan National Cancer Registry (NCR).
Methods
There were 26,542,445 active participants registered in the NHI database between 2001 and 2012. National Cancer Registry and NHI database records were compared for cancer diagnosis; date of cancer diagnosis; and 1, 2, and 5 year survival. In addition, the 10 leading causes of cancer deaths in Taiwan were analyzed.
Results
There were 908,986 cancer diagnoses in NCR and NHI database and 782,775 (86.1%) in both, with 53,192 (5.9%) in the NHI database only and 73,019 (8.0%) in the NCR only. The positive predictive value of the NHI database cancer diagnoses was 94% for all cancers; the positive predictive value of the 10 specific cancers ranged from 95% (lung cancer) to 82% (cervical cancer). The date of diagnosis in the NHI database was generally delayed by a median of 15 days (interquartile range 8‐18) compared with the NCR. The 1, 2, and 5 year survival rates were 71.21%, 60.85%, and 47.44% using the NHI database and were 71.18%, 60.17%, and 46.09% using NCR data.
Conclusions
Recording of cancer diagnoses and survival estimates based on these diagnosis codes in the NHI database are generally consistent with the NCR. Studies using NHI database data must pay careful attention to eligibility and record linkage; use of both sources is recommended.
Neural stem cells (NSCs), capable of ischemia‐homing, regeneration, and differentiation, exert strong therapeutic potentials in treating ischemic stroke, but the curative effect is limited in the ...harsh microenvironment of ischemic regions rich in reactive oxygen species (ROS). Gene transfection to make NSCs overexpress brain‐derived neurotrophic factor (BDNF) can enhance their therapeutic efficacy; however, viral vectors must be used because current nonviral vectors are unable to efficiently transfect NSCs. The first polymeric vector, ROS‐responsive charge‐reversal poly(2‐acryloyl)ethyl(p‐boronic acid benzyl)diethylammonium bromide (B‐PDEA), is shown here, that mediates efficient gene transfection of NSCs and greatly enhances their therapeutics in ischemic stroke treatment. The cationic B‐PDEA/DNA polyplexes can effectively transfect NSCs; in the cytosol, the B‐PDEA is oxidized by intracellular ROS into negatively charged polyacrylic acid, quickly releasing the BDNF plasmids for efficient transcription and secreting a high level of BDNF. After i.v. injection in ischemic stroke mice, the transfected NSCs (BDNF‐NSCs) can home to ischemic regions as efficiently as the pristine NSCs but more efficiently produce BDNF, leading to significantly augmented BDNF levels, which in turn enhances the mouse survival rate to 60%, from 0% (nontreated mice) or ≈20% (NSC‐treated mice), and enables more rapid and superior functional reconstruction.
The first nonviral gene carrier, reactive‐oxygen‐species‐responsive charge‐reversal poly(2‐acryloyl)‐ethyl(p‐boronic acid benzyl)diethylammonium bromide (B‐PDEA), is shown to mediate efficient gene transfection to neural stem cells (NSCs). When BDNF gene plasmids are used, the transfected NSCs homing to the ischemic regions increase animal survival and reconstruct functions.
Abstract
Ion leaching from pure-phase oxygen-evolving electrocatalysts generally exists, leading to the collapse and loss of catalyst crystalline matrix. Here, different from previous design ...methodologies of pure-phase perovskites, we introduce soluble BaCl
2
and SrCl
2
into perovskites through a self-assembly process aimed at simultaneously tuning dual cation/anion leaching effects and optimizing ion match in perovskites to protect the crystalline matrix. As a proof-of-concept, self-assembled hybrid Ba
0.35
Sr
0.65
Co
0.8
Fe
0.2
O
3-
δ
(BSCF) nanocomposite (with BaCl
2
and SrCl
2
) exhibits the low overpotential of 260 mV at 10 mA cm
-2
in 0.1 M KOH. Multiple
operando
spectroscopic techniques reveal that the pre-leaching of soluble compounds lowers the difference of interfacial ion concentrations and thus endows the host phase in hybrid BSCF with abundant time and space to form stable edge/face-sharing surface structures. These self-optimized crystalline structures show stable lattice oxygen active sites and short reaction pathways between Co–Co/Fe metal active sites to trigger favorable adsorption of OH
−
species.
Abstract
Autism spectrum disorder (ASD) is a common neurodevelopmental disorder. The mechanisms underlying ASD are unclear. Astrocyte alterations are noted in ASD patients and animal models. However, ...whether astrocyte dysfunction is causal or consequential to ASD-like phenotypes in mice is unresolved. Type 2 inositol 1,4,5-trisphosphate 6 receptors (IP3R2)-mediated Ca
2+
release from intracellular Ca
2+
stores results in the activation of astrocytes. Mutations of the IP3R2 gene are associated with ASD. Here, we show that both IP3R2-null mutant mice and astrocyte-specific IP3R2 conditional knockout mice display ASD-like behaviors, such as atypical social interaction and repetitive behavior. Furthermore, we show that astrocyte-derived ATP modulates ASD-like behavior through the P2X2 receptors in the prefrontal cortex and possibly through GABAergic synaptic transmission. These findings identify astrocyte-derived ATP as a potential molecular player in the pathophysiology of ASD.
Corner‐sharing and edge‐sharing networks are the two most important material genomes. Inspired by the efficient electron transport capacity of corner‐sharing structures and the low steric hindrance ...of edge‐sharing units, an attempt is made to exert both merits by combining these two networks. Here, a unique self‐assembled hybrid SrCo0.55Fe0.5O3‐δ nanorod composed of a corner‐sharing SrCo0.5Fe0.5O3‐δ phase and edge‐sharing Co3O4 structure is synthesized through a Co‐site enrichment method, which exhibits the low overpotentials of 310 and 290 mV at 10 mA cm–2 for oxygen‐evolving reaction in 0.1 m and 1.0 m KOH, respectively. This efficiency is attributed to the high Co valence with strong CoO covalence and the short distance between CoCo/Fe metal active sites in hybrid nanorods, realizing a synergistic benefit. Combined multiple operando/ex situ characterizations and computational studies show that the edge‐sharing units in hybrid nanorods can help facilitate the deprotonation step of lattice oxygen mechanism (LOM) while the corner‐sharing motifs can accelerate the electron transport during LOM processes, triggering an unusual lattice‐oxygen activation. This methodology of combining important material structural genomes can offer meaningful insights and guidance for various catalytic applications.
Based on material structural genomes, a unique hybrid‐phase SrCo0.55Fe0.5O3‐δ nanorod composed of corner‐sharing units (SrCo0.5Fe0.5O3‐δ perovskite) with strong electron transport capacity and edge‐sharing motifs (Co3O4 spinel) with low reaction steric hindrance by a self‐assembled Co‐site enrichment method are developed. SrCo0.55Fe0.5O3‐δ nanorod exhibits efficient oxygen‐evolving performance with exceptional lattice oxygen activation.
Human activities have shaped large-scale distributions of many species, driving both range contractions and expansions. Species differ naturally in range size, with small-range species concentrated ...in particular geographic areas and potentially deviating ecologically from widespread species. Hence, species’ responses to human activities may be influenced by their geographic range sizes, but if and how this happens are poorly understood. Here, we use a comprehensive distribution database and species distribution modeling to examine if and how human activities have affected the extent to which 9,701 vascular plants fill their climatic potential ranges in China. We find that narrow-ranged species have lower range filling and widespread species have higher range filling in the human-dominated southeastern part of China, compared with their counterparts distributed in the less human-influenced northwestern part. Variations in range filling across species and space are strongly associated with indicators of human activities (human population density, human footprint, and proportion of cropland) even after controlling for alternative drivers. Importantly, narrow-ranged and widespread species show negative and positive range-filling relationships to these human indicators, respectively. Our results illustrate that floras risk biotic homogenization as a consequence of anthropogenic activities, with narrow-ranged species becoming replaced by widespread species. Because narrow-ranged species are more numerous than widespread species in nature, negative impacts of human activities will be prevalent. Our findings highlight the importance of establishing more protected areas and zones of reduced human activities to safeguard the rich flora of China.
Structural degradation in manganese oxides leads to unstable electrocatalytic activity during long-term cycles. Herein, we overcome this obstacle by using proton exchange on well-defined layered Li
...MnO
with an O3-type structure to construct protonated Li
H
MnO
with a P3-type structure. The protonated catalyst exhibits high oxygen reduction reaction activity and excellent stability compared to previously reported cost-effective Mn-based oxides. Configuration interaction and density functional theory calculations indicate that Li
H
MnO
has fewer unstable O 2p holes with a Mn
valence state and a reduced interlayer distance, originating from the replacement of Li by H. The former is responsible for the structural stability, while the latter is responsible for the high transport property favorable for boosting activity. The optimization of both charge states to reduce unstable O 2p holes and crystalline structure to reduce the reaction pathway is an effective strategy for the rational design of electrocatalysts, with a likely extension to a broad variety of layered alkali-containing metal oxides.
Drought is one of the major abiotic stresses affecting plant growth, development and crop productivity. ABA responsive element binding factor (ABF) plays an important role in stress responses via ...regulating the expression of stress-responsive genes.
In this study, a gene coding for ABF (PtrABF) was isolated from Poncirus trifoliata (L.) Raf. PtrABF had a complete open reading frame of 1347 bp, encoding a 448 amino acid peptide, and shared high sequence identities with ABFs from other plants. PtrABF was subcellularly targeted to the nucleus, exhibited transactivation activity in yeast cell and could bind to ABRE, supporting its role as a transcription factor. Expression levels of PtrABF were induced by treatments with dehydration, low temperature and ABA. Ectopic expression of PtrABF under the control of a CaMV 35S promoter in transgenic tobacco plants enhanced tolerance to both dehydration and drought. Under dehydration and drought conditions, the transgenic plants accumulated lower levels of reactive oxygen species compared with wild type, accompanied by higher activities and expression levels of three antioxidant enzymes. In addition, steady-state mRNA levels of nine stress-responsive genes coding for either functional or regulatory proteins were induced to higher levels in the transgenic lines with or without drought stress.
PtrABF is a bZIP transcription factor and functions in positive modulation of drought stress tolerance. It may be an important candidate gene for molecular breeding of drought-tolerant plants.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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