In radiomics studies, researchers usually need to develop a supervised machine learning model to map image features onto the clinical conclusion. A classical machine learning pipeline consists of ...several steps, including normalization, feature selection, and classification. It is often tedious to find an optimal pipeline with appropriate combinations. We designed an open-source software package named FeAture Explorer (FAE). It was programmed with Python and used NumPy, pandas, and scikit-learning modules. FAE can be used to extract image features, preprocess the feature matrix, develop different models automatically, and evaluate them with common clinical statistics. FAE features a user-friendly graphical user interface that can be used by radiologists and researchers to build many different pipelines, and to compare their results visually. To prove the effectiveness of FAE, we developed a candidate model to classify the clinical-significant prostate cancer (CS PCa) and non-CS PCa using the PROSTATEx dataset. We used FAE to try out different combinations of feature selectors and classifiers, compare the area under the receiver operating characteristic curve of different models on the validation dataset, and evaluate the model using independent test data. The final model with the analysis of variance as the feature selector and linear discriminate analysis as the classifier was selected and evaluated conveniently by FAE. The area under the receiver operating characteristic curve on the training, validation, and test dataset achieved results of 0.838, 0.814, and 0.824, respectively. FAE allows researchers to build radiomics models and evaluate them using an independent testing dataset. It also provides easy model comparison and result visualization. We believe FAE can be a convenient tool for radiomics studies and other medical studies involving supervised machine learning.
A dielectric constant transition is chemically triggered and thermally switched in (HPy)2Na(H2O)Co(CN)6 (2, HPy=pyridinium cation) by single‐crystal‐to‐single‐crystal transformation and structural ...phase transition, respectively. Upon dehydration, (HPy)2Na(H2O)2Co(CN)6 (1) transforms to its semi‐hydrated form 2, accompanying a transition from a low‐dielectric state to a high‐dielectric state, and vice versa. This dielectric switch is also realized by a structural phase transition in 2 that occurs between room‐ and low‐temperature phases, and which corresponds to high‐ and low‐dielectric states, respectively. The switching property is due to the variation in the environment surrounding the HPy cation, that is, the hydrogen‐bonding interactions and the crystal packing, which exert predominant influences on the dynamics of the cations that transit between the static and motional states.
A dielectric constant transition is observed in (HPy)2Na(H2O)Co(CN)6 (HPy=pyridinium cation). This transition is chemically triggered by water in a single‐crystal‐to‐single‐crystal transformation (see picture; right) and thermally switched (left) in a structural phase transition.
Deuteration of a hydrogen bond by replacing protium (H) with deuterium (D) can cause geometric changes in the hydrogen bond, known as the geometric H/D isotope effect (GIE). Understanding the GIEs on ...global structures and bulk properties is of great importance to study structure-property relationships of hydrogen-bonded systems. Here, we report a hydrogen-bonded host-guest crystal, imidazolium hydrogen terephthalate, that exemplifies striking GIEs on its hydrogen bonds, phases, and bulk dielectric transition property. Upon deuteration, the donor-acceptor distance in the O-H···O hydrogen bonds in the host structure is found to increase, which results in a change in the global hydrogen-bonded supramolecular structure and the emergence of a new phase (i.e., isotopic polymorphism). Consequently, the dynamics of the confined guest, which depend on the internal pressure exerted by the host framework, are substantially altered, showing a downward shift of the dielectric switching temperature.
2D organic–inorganic hybrid perovskites (OIHPs) have become one of the hottest research topics due to their excellent environmental stability and unique optoelectronic properties. Recently, the ...ferroelectricity and thermochromism of 2D OIHPs have attracted increasing interests. Integrating ferroelectricity and thermochromism into perovskites can significantly promote the development of multichannel intelligent devices. Here, a novel 2D Dion‐Jacobson OIHP of the formula (3AMP)PbI4 (where 3AMP is 3‐(aminomethyl)pyridinium) is reported, which has a remarkable spontaneous polarization value (Ps) of 15.6 µC cm−2 and interesting thermochromism. As far it is known, such a large Ps value is the highest for 2D OIHPs recorded so far. These findings will inspire further exploration and application of multifunctional perovskites.
Coupling of ferroelectricity and optical properties has emerged as a captivating aspect of material research. This work demonstrates that (3AMP)PbI4 (3AMP = 3‐(aminomethyl)pyridinium), a 2D Dion–Jacobson perovskite, not only boasts a remarkable spontaneous polarization, but also displays unique thermochromism. These findings will inspire further exploration and application of multifunctional perovskites.
A new category of crystalline polymer electrolyte prepared by the supramolecular self‐assembly of polyethylene oxide (PEO), α‐cyclodextrin (α‐CD), and LiAsF6 is reported. The polymer electrolyte ...consists of the nanochannels formed by α‐CDs in which the PEO/Li+ complexes are confined. The nanochannels formed by α‐CD provide the pathway for the directional motion of Li+ ions and at the same time prevent the access of the anions by size exclusion, resulting in good separation of the Li+ ions and the anions. The conductivity of the reported material is 30 times higher than that of the comparable PEO/Li+ complex crystal at room temperature. By using state‐of‐art solid‐state NMR spectroscopy, the structure and dynamics of the material were investigated in detail. The dynamics of the Li+ ions was studied and correlated to the ionic conductivity of the material.
A new category of crystalline polymer electrolyte has been prepared by the supramolecular self‐assembly of PEO (see picture, black), α‐cyclodextrin (α‐CD, blue), and LiAsF6. In this polymer electrolyte, the nanochannels formed by α‐CD provide the pathway for the directional motion of Li+ ions (colored spheres, 5 different environments) and at the same time prevent access of the anions by size exclusion, thereby resulting in good separation of the Li+ ions and the anions.
Background
Gamma‐aminobutyric acid (GABA) is an inhibitory neurotransmitter in human brains, playing a role in the pathogenesis of various psychiatric disorders. Current methods have some ...non‐neglectable shortcomings and noninvasive and accurate detection of GABA in human brains is long‐term challenge.
Purpose
To develop a pulse sequence capable of selectively detecting and quantifying the 1H signal of GABA in human brains based on optimal controlled spin singlet order.
Study Type
Prospective.
Subjects/Phantom
A phantom of GABA (pH = 7.3 ± 0.1) and 11 healthy subjects (5 females and 6 males, body mass index: 21 ± 3 kg/m2, age: 25 ± 4 years).
Field Strength/Sequence
7 Tesla, 3 Tesla, GABA‐targeted magnetic resonance spectroscopy (GABA‐MRS‐7 T, GABA‐MRS‐3 T), magnetization prepared two rapid acquisition gradient echoes sequence.
Assessment
By using the developed pulse sequences applied on the phantom and healthy subjects, the signals of GABA were successfully selectively probed. Quantification of the signals yields the concentration of GABA in the dorsal anterior cingulate cortex (dACC) in human brains.
Statistical Tests
Frequency.
Results
The 1H signals of GABA in the phantom and in the human brains of healthy subjects were successfully detected. The concentration of GABA in the dACC of human brains was 3.3 ± 1.5 mM.
Data Conclusion
The developed pulse sequences can be used to selectively probe the 1H MR signals of GABA in human brains in vivo.
Evidence Level
1
Technical Efficacy Stage
1
A novel dodecanuclear Zr oxo cluster Zr6O4(OH)4 (HSCH2CH2COO)122 (ZrO‐SH‐10) has been constructed under the room temperature, followed by oxidation of the sulfhydryl group with H2O2 to achieve a ...bifunctional catalyst with Lewis acid and Brönsted acid sites. The characterization of catalysts indicated that {Zr6O4} cluster core can be stabilized with a shell of carboxylate ligands, and the resulting ZrO‐SO3H was formed as a discrete molecular catalyst, exhibiting superior activity and recyclability for the cascade conversion of furfural to alkyl levulinate by the integration of transfer hydrogenation and alcoholysis in n‐butanol. The yield of n‐butyl levulinate can achieve as high as 91 % under the optimum conditions. Meanwhile, no leaching of the active species was found, which confirmed the structure of the Zr oxo cluster was air and moisture‐stable. On the basis of the studies on the reaction kinetics and isotope tracking, the reaction mechanism was proposed accordingly.
Zr oxo cluster bifunctional catalyst: The Zr oxo cluster Zr6O4(OH)4 (HSCH2CH2COO)122 has been developed, and then the molecular catalyst with Lewis acid and Brönsted acid sites were attained by the oxidation of the sulfhydryl group of the Zr oxo cluster with H2O2. The resulting bifunctional catalyst showed a superior catalytic activity for alcoholysis of furfural to alkyl levulinates.
Background
The high level of expertise required for accurate interpretation of prostate MRI.
Purpose
To develop and test an artificial intelligence (AI) system for diagnosis of clinically significant ...prostate cancer (CsPC) with MRI.
Study Type
Retrospective.
Subjects
One thousand two hundred thirty patients from derivation cohort between Jan 2012 and Oct 2019, and 169 patients from a publicly available data (U‐Net: 423 for training/validation and 49 for test and TrumpeNet: 820 for training/validation and 579 for test).
Field Strength/Sequence
3.0T/scanners, T2‐weighted imaging (T2WI), diffusion‐weighted imaging, and apparent diffusion coefficient map.
Assessment
Close‐loop AI system was trained with an Unet for prostate segmentation and a TrumpetNet for CsPC detection. Performance of AI was tested in 410 internal and 169 external sets against 24 radiologists categorizing into junior, general and subspecialist group. Gleason score >6 was identified as CsPC at pathology.
Statistical Tests
Area under the receiver operating characteristic curve (AUC‐ROC); Delong test; Meta‐regression I2 analysis.
Results
In average, for internal test, AI had lower AUC‐ROC than subspecialists (0.85 vs. 0.92, P < 0.05), and was comparable to junior (0.84, P = 0.76) and general group (0.86, P = 0.35). For external test, both AI (0.86) and subspecialist (0.86) had higher AUC than junior (0.80, P < 0.05) and general reader (0.83, P < 0.05). In individual, it revealed moderate diagnostic heterogeneity in 24 readers (Mantel–Haenszel I2 = 56.8%, P < 0.01), and AI outperformed 54.2% (13/24) of readers in summary ROC analysis. In multivariate test, Gleason score, zonal location, PI‐RADS score and lesion size significantly impacted the accuracy of AI; while effect of data source, MR device and parameter settings on AI performance is insignificant (P > 0.05).
Data Conclusion
Our AI system can match and to some case exceed clinicians for the diagnosis of CsPC with prostate MRI.
Evidence Level
3
Technical Efficacy
Stage 2
Amino acids are the building blocks of proteins and are widely used as important ingredients for other nitrogen‐containing molecules. Here, we report the sustainable production of amino acids from ...biomass‐derived hydroxy acids with high activity under visible‐light irradiation and mild conditions, using atomic ruthenium‐promoted cadmium sulfide (Ru1/CdS). On a metal basis, the optimized Ru1/CdS exhibits a maximal alanine formation rate of 26.0 molAla ⋅ gRu−1 ⋅ h−1, which is 1.7 times and more than two orders of magnitude higher than that of its nanoparticle counterpart and the conventional thermocatalytic process, respectively. Integrated spectroscopic analysis and density functional theory calculations attribute the high performance of Ru1/CdS to the facilitated charge separation and O−H bond dissociation of the α‐hydroxy group, here of lactic acid. The operando nuclear magnetic resonance further infers a unique “double activation” mechanism of both the CH−OH and CH3−CH−OH structures in lactic acid, which significantly accelerates its photocatalytic amination toward alanine.
Here we report ruthenium single‐atom catalysts loaded on ultrathin CdS nanosheets (Ru1/CdS), which efficiently catalyze biomass‐derived α‐hydroxy acids to produce amino acids under visible light irradiation. The optimal system predominates the conventional thermocatalytic and photocatalytic systems in terms of conversion, selectivity, yield, and amino acid formation rates.
Detailed information about the influences of the cooperative motion of water and methanol molecules on practical solid–liquid heterogeneous photocatalysis reactions is critical for our understanding ...of photocatalytic reactions. The present work addresses this issue by applying operando nuclear magnetic resonance (NMR) spectroscopy, in conjunction with density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations, to investigate the dynamic behaviors of heterogeneous photocatalytic systems with different molar ratios of water to methanol on rutile-TiO2 photocatalyst. The results demonstrate that methanol and water molecules are involved in the cooperative motions, and the cooperation often takes the form of methanol–water clusters that govern the number of methanol molecules reaching to the active sites of the photocatalyst per unit time, as confirmed by the diffusion coefficients of the methanol molecule calculated in the binary methanol–water solutions. Nuclear Overhauser effect spectroscopy experiments reveal that the clusters are formed by the hydrogen bonding between the −OH groups of CH3OH and H2O. The formation of such methanol–water clusters is likely from an energetic standpoint in low-concentration methanol, which eventually determines the yields of methanol reforming products.
PDF
