New oxide structures clearing up the origin of two-dimensional electron gas in AlGaN/GaN heterostructures.

Control over the two-dimensional electron gas (2DEG) in AlGaN/GaN heterostructures is crucial for their practical applications in current semiconducting devices. However, the oxide surface structures inducing 2DEG are still ambiguous because oxide-stoichiometry (OS) matching structures possess occupied surface donor states at 1.0-1.8 eV below the conduction band minimum of bulk but are usually not available in energy than electron counting (EC) rule structures. In this work, a global optimization algorithm was introduced to explore the possible oxidation structures on GaN (0001) and AlN (0001) surfaces; the method was demonstrated to be available due to the fact that the reported oxidized structures were reproduced at each stoichiometry. Interestingly, the two similar oxide structures with close energy were found in each oxide-bilayer, which can be used to clarify the experimental observations of disordered surface oxide layers below 550 °C. Additionally, new stable oxidation structures with low surface energy were proposed. Interestingly, the new OS matching structures are proposed with remarkably lower energy than EC rule structures under cation-rich and oxygen-poor conditions, which is caused by the large formation enthalpy of Al2O3 and Ga2O3. Further electronic structure calculations demonstrate that the new OS structures possess highest occupied states above the half of the gap and are the origin of 2DEG in AlGaN/GaN heterostructures.

Tractable Method for Rapid Quality Assessment of Therapeutic Antibodies in Harvested Cell Culture Fluid based on FcγRIIIa-Immobilized Magnetic Microspheres.

FcγRIIIa-binding affinity is one of the key factors to ensure the efficacy of many antitumor therapeutic antibodies, which should be monitored along with the titer, protein aggregation, and other critical quality attributes. The conventional workflow for the quality assessment of therapeutic antibodies in harvested cell culture fluid (HCCF) is time-consuming and costly nevertheless. In this study, a tractable method was established for rapid quality assessment of a HCCF sample through differentially extracting IgG with different FcγRIIIa affinity levels using FcγRIIIa-immobilized magnetic microspheres, followed by size exclusion chromatography (SEC) to determine the amount and monomer percentage of IgGs in the preceding eluate. FcγRIIIa-immobilized magnetic microspheres with polydopamine (PDA) and hydrophilic dendrimer (PAMAM) coating (denoted as Fe3O4@PDA@PAMAM-FcγRIIIa) were synthesized for the first time as magnetic adsorbents. The PDA cladding endowed the composites with good chemical stability in acidic elution buffer, and the PAMAM dendrimer empowered the composites of high ligand immobilization capacity and hydrophilic surface. The labile FcγRIIIa was immobilized under mild conditions. By directly applying a simple magnetic solid phase extraction procedure to treat HCCF, favored IgG species with high FcγRIIIa affinity would be selectively captured by Fe3O4@PDA@PAMAM-FcγRIIIa composites for subsequent SEC analysis. The monomer peak area value in SEC, which was set as the read-out of the proposed method, correlated directly with the theoretical overall quality of standard-spiked HCCF samples.

Extension of a fifth-order intrinsic aberration for a soft x-ray and vacuum ultraviolet optical system from a one- to two-dimension field light source.

Based on the fifth-order intrinsic aberration of a soft x-ray and vacuum ultraviolet (XUV) optical system with a one-dimension field light source, it is extended to the case of two-dimension in this paper, and the corresponding aberration calculation method is studied. Firstly, we derived sixth-order intrinsic wave aberration expressions of these kinds of optical systems with the aperture-ray coordinates on the reference exit wavefront; and then, derived the calculation expressions for fifth-order intrinsic aberration on the image plane caused by the contributions of wave aberration and defocus, respectively. Finally, the aberration expressions derived in this paper are applied to calculate the aberration distributions of two design examples of these kinds of optical systems, and these calculation results are compared with the ray-tracing program Shadow to validate the aberration expressions. The study shows that the calculation accuracy of aberration expressions is very satisfactory.

Fifth-order aberration for soft x-ray and vacuum ultraviolet multi-element optical systems.

Based on the recently developed fifth-order intrinsic aberration of a soft x-ray and vacuum ultraviolet single-element optical system, this paper proposes a fifth-order aberration (including intrinsic aberration and extrinsic aberration) calculation method for this kind of optical system with multiple elements. First, the fifth-order intrinsic aberration expressions of soft x-ray and vacuum ultraviolet multi-element optical systems are studied; second, the extrinsic aberration calculation method of this kind of optical system is discussed, and corresponding calculation expressions are derived; third, to improve aberration calculation accuracy, the modification of aberration expressions due to the transfer relationship of aperture-ray coordinates with second-order accuracy on the reference exit wavefront between adjacent optical elements is obtained. Finally, the resultant aberration expressions are applied to calculate the aberration of two design examples of soft x-ray and vacuum ultraviolet double-element optical systems with large apertures, and their images are compared with ray-tracing results using Shadow software to validate the aberration expressions. The study shows that the accuracy of the aberration expressions derived in this paper is satisfactory.

Magnetic covalent-organic frameworks-based extraction followed by UHPLC-MS/MS for determination and pharmacokinetic study of trace angoroside C in rat plasma after oral administration of Xuanbo Shuangsheng Granule.

The composition of the traditional Chinese medicine compound preparation is complex, while the content of each active ingredient is extremely low, which brings difficulties to the plasma concentration detection. In this study, the magnetic covalent-organic frameworks were synthesized by a simple one-step Schiff base reaction and applied for the specific extraction of trace angoroside C in rat plasma prior to ultra-high-performance liquid chromatography-tandem mass spectrometry detection. The synthesized magnetic covalent-organic frameworks have high magnetic responsiveness (35.67 emu·g-1 ), large surface area (110.9 m2 ·g-1 ), and strong stability. The as-prepared material can quickly extract angoroside C from plasma with high extraction efficiency, be easily separated with a magnet afterward, and can be reused for at least five times. The established method was systematically validated showing good linearity (0.1-5 ng·ml-1 ), low limit of quantification (0.1 ng·ml-1 ), good accuracy (93.18-105.36%), and good precision (percentage relative standard deviation 3.60-10.90%). Finally, the method was used to the pharmacokinetic study of trace angoroside C in rats after oral administration of Xuanbo Shuangsheng Granule.

Interactions between Human Serum Albumin and Sulfadimethoxine Determined Using Spectroscopy and Molecular Docking.

Sulfonamides are widely used antibiotics in agricultural production. However, the potential threat of these drugs to human health has increased global concern. Human serum albumin (HSA) is the main reservoir and transporter of exogenous small molecules in humans. In this study, the interaction between sulfadimethoxine (SMT) and human serum albumin (HSA) was studied using spectroscopy and computer simulation. Our results showed that the hydrogen bonding and van der Waals forces drove SMT to enter the binding site I of HSA spontaneously and resulted in the fluorescence quenching of HSA. The stability of the HSA-SMT complex decreased with an increase in temperature. The binding of SMT to HSA induced alterations in the secondary structure of HSA, where the content of α-helix decreased from 61.0% of the free state to 59.0% of the compound state. The π-π, π-σ, and π-alkyl interactions between HSA and SMT were found to play important roles in maintaining the stability of the complex.

Two-Dimensional Organic Supramolecule via Hydrogen Bonding and π-π Stacking for Ultrahigh Capacity and Long-Life Aqueous Zinc-Organic Batteries.

Aqueous zinc-ion batteries (ZIBs) are promising for next-generation energy storage. However, the reported electrode materials for ZIBs are facing shortcomings including low capacity and unsatisfactory cycling stability etc. Herein, hexaazatrinaphthalene-quione (HATNQ) is reported for aqueous ZIBs. The HATNQ electrodes delivered an ultrahigh capacity (482.5 mAh g-1 at 0.2 A g-1 ) and outstanding cyclability of >10 000 cycles at 5 A g-1 . The capacity sets a new record for organic cathodes in aqueous ZIBs. The high performances are ascribed to the rich C=O and C=N groups that endowed HATNQ with a 2D layered supramolecular structure by multiple hydrogen bonds in plane with π-π interactions out-of-plane, leading to enhanced charge transfer, insolubility, and rapid ion transport for fast-charge and -discharge batteries. Moreover, the 2D supramolecular structure boosted the storage of Zn2+ /H+ , particularly the storage of Zn2+ , due to the more favorable O⋅⋅⋅Zn⋅⋅⋅N coordination in HATNQ.

Fifth-order intrinsic aberration calculation method for soft x-ray and vacuum ultraviolet optical systems.

In this paper, we propose the fifth-order intrinsic aberration calculation method for soft x-ray and vacuum ultraviolet optical systems. First, the sixth-order intrinsic wave aberrations with the aperture-ray coordinates on the optical surface are derived based on the wave aberration method, and then applying the sixth-order mapping relationship of aperture-ray coordinates between the optical surface and the reference exit wavefront, the expressions with those on the reference exit wavefront can be obtained. Second, we derived the calculation expression for the fifth-order intrinsic aberration on the image plane. Finally, the fifth-order intrinsic aberration calculation expressions of the soft x-ray and vacuum ultraviolet optical system derived in this paper are applied to calculate the aberration distribution on the image plane of two design examples of this kind of optical system, and the calculation results are compared with the ray-tracing ones with Shadow software to validate the aberration expressions. The study shows that the accuracy of the aberration expressions is satisfactory.

Third-order aberration of soft X-ray optical systems with orthogonal and coplanar arrangement of the main planes of elements.

A third-order aberration analytical analysis method of soft X-ray optical systems with orthogonal and coplanar arrangement of the main planes of elements is proposed. Firstly, the transfer equations of the aperture ray and the principle ray are derived; then, based on the third-order aberration theory with the aperture-ray coordinates on the reference exit wavefront of a plane-symmetric optical system, the aberration expressions contributed by the wave aberration and defocus of this kind of optical system are studied in detail. Finally, the derived aberration calculation expressions are applied to calculate the aberration of two design examples of such types of optical systems; the images are compared with ray-tracing results obtained using the Shadow software to validate the aberration expressions. The study shows that the accuracy of the aberration expressions is satisfactory. The analytical analysis method of aberration is helpful in the design and optimization of the soft X-ray optical systems with orthogonal and coplanar arrangement of the main planes of optical elements.

Method of calculating the aberrations of soft X-ray and vacuum ultraviolet optical systems.

Based on the the third-order aberration theory of plane-symmetric optical systems, this paper studies the effect on aberrations of the second-order accuracy of aperture-ray coordinates and the extrinsic aberrations of this kind of optical system; their calculation expressions are derived. The resultant aberration expressions are then applied to calculate the aberrations of two design examples of soft X-ray and vacuum ultraviolet (XUV) optical systems; images are compared with ray-tracing results using SHADOW software to validate the aberration expressions. The study shows that the accuracy of the aberration expressions is satisfactory.

Chromatic aberration of plane-symmetric optical systems: publisher's note.

This publisher's note amends the funding in Appl. Opt.58, 227 (2019)APOPAI0003-693510.1364/AO.58.000227.

Chromatic aberration of plane-symmetric optical systems.

This paper presents a calculation method of chromatic aberration of such kinds of optical systems based on the aberration theory of plane-symmetric optical systems, and the analytic expressions of the axial chromatic aberration and chromatic change in the magnification at an image plane of any position are derived. The resultant expressions are used to calculate the chromatic aberration of two single-lens optical systems with a large incidence angle, and the calculation results are compared to the ones obtained from a ray-tracing program to validate the chromatic aberration expressions. The study shows that the calculation accuracy of the chromatic aberration expressions is satisfactory. The analytical analysis of chromatic aberration is helpful in the imaging analysis and design of plane-symmetric optical systems.

Sixth-order wave aberration theory of ultrawide-angle optical systems: erratum.

In this erratum, two errors in our recently published paper [Appl. Opt.56, 8570 (2017)APOPAI0003-693510.1364/AO.56.008570] are corrected.

Modulation transfer function of a fish-eye lens based on the sixth-order wave aberration theory.

A calculation program of the modulation transfer function (MTF) of a fish-eye lens is developed with the autocorrelation method, in which the sixth-order wave aberration theory of ultra-wide-angle optical systems is used to simulate the wave aberration distribution at the exit pupil of the optical systems. The autocorrelation integral is processed with the Gauss-Legendre integral, and the magnification chromatic aberration is discussed to calculate polychromatic MTF. The MTF calculation results of a given example are then compared with those previously obtained based on the fourth-order wave aberration theory of plane-symmetrical optical systems and with those from the Zemax program. The study shows that MTF based on the sixth-order wave aberration theory has satisfactory calculation accuracy even for a fish-eye lens with a large acceptance aperture. And the impacts of different types of aberrations on the MTF of a fish-eye lens are analyzed. Finally, we apply the self-adaptive and normalized real-coded genetic algorithm and the MTF developed in the paper to optimize the Nikon F/2.8 fish-eye lens; consequently, the optimized system shows better MTF performances than those of the original design.

Aberrations of soft x-ray and vacuum ultraviolet optical systems with orthogonal arrangement of elements.

The wave aberration of plane-symmetric optical systems is expressed with the aperture-ray coordinates on the reference exit wavefront in the paper; the defocus aberration caused by the meridional field of source is analyzed in detail. Based on the expressions of the wave aberration and the defocus, the aberrations of the soft x-ray and ultraviolet (XUV) optical systems with an orthogonal arrangement of elements are studied as a whole. The resultant aberration expressions are used to calculate the aberrations of two design examples; the images are compared to the ray-tracing results with Shadow to validate the aberration expressions. The study shows that the accuracy of the aberration expressions is satisfactory. The analytical analysis of aberrations is helpful in the design and optimization of the XUV optical systems with an orthogonal arrangement of elements.

Sixth-order wave aberration theory of ultrawide-angle optical systems.

In this paper, we develop sixth-order wave aberration theory of ultrawide-angle optical systems like fisheye lenses. Based on the concept and approach to develop wave aberration theory of plane-symmetric optical systems, we first derive the sixth-order intrinsic wave aberrations and the fifth-order ray aberrations; second, we present a method to calculate the pupil aberration of such kind of optical systems to develop the extrinsic aberrations; third, the relation of aperture-ray coordinates between adjacent optical surfaces is fitted with the second-order polynomial to improve the calculation accuracy of the wave aberrations of a fisheye lens with a large acceptance aperture. Finally, the resultant aberration expressions are applied to calculate the aberrations of two design examples of fisheye lenses; the calculation results are compared with the ray-tracing ones with Zemax software to validate the aberration expressions.

MMBERT: a unified framework for biomedical named entity recognition.

Named entity recognition (NER) is an important task in natural language processing (NLP). In recent years, NER has attracted much attention in the biomedical field. However, due to the lack of biomedical named entity identification datasets, the complexity and rarity of biomedical named entities and so on, biomedical NER is more difficult than general domain NER. So in this paper, we propose a framework (MMBERT) based on Transformer to solve the problems above. To address the scarcity of biomedical named entity recognition datasets, we introduce ERNIE-Health, a new Chinese language representation model pre-trained on large-scale biomedical text corpora. Because of the complexity and rarity of biomedical named entities, we use the Bert and CW-LSTM structures to get the joint feature vector of word pairs relations. In addition, we design multi-granularity 2D convolution to refine the relationship and representation between word pairs. Finally, we design a convolutional neural network (CNN) structure and a co-predictor to improve the model's generalization capability and prediction accuracy. We have conducted extensive experiments on three benchmark datasets, and the experimental results show that our model achieves the best results compared with several baseline models in the experiment.

Research on carbon and nitrogen removal of tetramethylammonium hydroxide containing wastewater by combined anaerobic/integrated fixed film activated sludge process.

Tetramethylammonium hydroxide (TMAH) is widely used as a developer and etchant in the thin-film transistor liquid crystal display industry, which is the main component of developer wastewater with low C/N ratio. This study investigated TMAH degradation by combined anaerobic/integrated fixed film activated sludge (A/IFAS) process, especially for nitrogen removal. Effects of process condition on the TMAH degradation were studied, including dissolved oxygen concentration in IFAS reactor and the temperature of anaerobic reactor. Especially, the nitrogen removal was studied through the monitoring of intermediate products during TMAH biodegradation. The results indicated that lower the anaerobic treatment temperature can provide more available organic matters to enhance the denitrification in the subsequent IFAS reactor. Less oxygen supply in the IFAS reactor contributed to simultaneous nitrification and denitrification. Removal efficiency of total organic carbon and total nitrogen was up to 95.8% and 80.7%, when the temperature of anaerobic treatment was controlled at 30 °C with the DO kept at 0.7 mg/L. It indicated that A/IFAS process was efficient in carbon and nitrogen removal for TMAH degradation. The results also confirmed intermediate products of TMAH biodegradation can be used as the electron donor during denitrification, including trimethylamine, dimethylamine and methylamine. Illumina MiSeq sequencing showed that Proteobacteria was the dominant phylum contribute to nitrogen removal. Compared to sludge flocs in IFAS reactor, richer community and higher microbial diversity were observed in the biofilm.

NMDA Receptor-Dependent Synaptic Potentiation via APPL1 Signaling Is Required for the Accessibility of a Prefrontal Neuronal Assembly in Retrieving Fear Extinction.

BACKGROUND: The ventromedial prefrontal cortex has been viewed as a locus for storage and recall of extinction memory. However, the synaptic and cellular mechanisms underlying these processes remain elusive. METHODS: We combined transgenic mice, electrophysiological recording, activity-dependent cell labeling, and chemogenetic manipulation to analyze the role of adaptor protein APPL1 in the ventromedial prefrontal cortex in fear extinction retrieval. RESULTS: We found that both constitutive and conditional APPL1 knockout decreased NMDA receptor (NMDAR) function in the ventromedial prefrontal cortex and impaired fear extinction retrieval. Moreover, APPL1 undergoes nuclear translocation during extinction retrieval. Blocking APPL1 nucleocytoplasmic translocation reduced NMDAR currents and disrupted extinction retrieval. We also identified a prefrontal neuronal ensemble that is both necessary and sufficient for the storage of extinction memory. Inducible APPL1 knockout in this ensemble abolished NMDAR-dependent synaptic potentiation and disrupted extinction retrieval, while chemogenetic activation of this ensemble simultaneously rescued the impaired behaviors. CONCLUSIONS: Our results indicate that a prefrontal neuronal ensemble stores extinction memory, and APPL1 signaling supports these neurons in retrieving extinction memory by controlling NMDAR-dependent potentiation.

Core-shell structured magnetic covalent-organic frameworks for rapid extraction and preconcentration of okadaic acid in seawater and shellfish followed with LC-MS/MS quantification.

Core-shell structured magnetic covalent-organic frameworks (Fe3O4@TaTp) were facilely synthesized based on one-step functionalization at room temperature and applied for magnetic solid-phase extraction of okadaic acid from seawater and shellfish prior to LC-MS/MS detection. Parameters, including adsorbent amount, extraction time, desorption solution, and desorption time which could affect the extraction efficiency, were respectively investigated. The developed methods demonstrated good linearity (R2 > 0.99), acceptable accuracy and good precision (<15%), and low limit of detection (0.5 pg·mL-1 for seawater and 0.04 µg·kg-1 for shellfish). The amount of the material used (1 mg for seawater and 5 mg for shellfish) and the time required (4 min for seawater and 15 min for shellfish) for extracting analyte from 5 mL of seawater and 2 g of shellfish are both greatly shortened compared with the previous reports. In addition, we successfully applied this method to real sample analysis.