A crossbar array of magnetoresistive memory devices for in-memory computing.

Implementations of artificial neural networks that borrow analogue techniques could potentially offer low-power alternatives to fully digital approaches1-3. One notable example is in-memory computing based on crossbar arrays of non-volatile memories4-7 that execute, in an analogue manner, multiply-accumulate operations prevalent in artificial neural networks. Various non-volatile memories-including resistive memory8-13, phase-change memory14,15 and flash memory16-19-have been used for such approaches. However, it remains challenging to develop a crossbar array of spin-transfer-torque magnetoresistive random-access memory (MRAM)20-22,  despite the technology's practical advantages such as endurance and large-scale commercialization5. The difficulty stems from the low resistance of MRAM, which would result in large power consumption in a conventional crossbar array that uses current summation for analogue multiply-accumulate operations. Here we report a 64 × 64 crossbar array based on MRAM cells that overcomes the low-resistance issue with an architecture that uses resistance summation for analogue multiply-accumulate operations. The array is integrated with readout electronics in 28-nanometre complementary metal-oxide-semiconductor technology. Using this array, a two-layer perceptron is implemented to classify 10,000 Modified National Institute of Standards and Technology digits with an accuracy of 93.23 per cent (software baseline: 95.24 per cent). In an emulation of a deeper, eight-layer Visual Geometry Group-8 neural network with measured errors, the classification accuracy improves to 98.86 per cent (software baseline: 99.28 per cent). We also use the array to implement a single layer in a ten-layer neural network to realize face detection with an accuracy of 93.4 per cent.

Heterogeneous integration of single-crystalline complex-oxide membranes.

Complex-oxide materials exhibit a vast range of functional properties desirable for next-generation electronic, spintronic, magnetoelectric, neuromorphic, and energy conversion storage devices1-4. Their physical functionalities can be coupled by stacking layers of such materials to create heterostructures and can be further boosted by applying strain5-7. The predominant method for heterogeneous integration and application of strain has been through heteroepitaxy, which drastically limits the possible material combinations and the ability to integrate complex oxides with mature semiconductor technologies. Moreover, key physical properties of complex-oxide thin films, such as piezoelectricity and magnetostriction, are severely reduced by the substrate clamping effect. Here we demonstrate a universal mechanical exfoliation method of producing freestanding single-crystalline membranes made from a wide range of complex-oxide materials including perovskite, spinel and garnet crystal structures with varying crystallographic orientations. In addition, we create artificial heterostructures and hybridize their physical properties by directly stacking such freestanding membranes with different crystal structures and orientations, which is not possible using conventional methods. Our results establish a platform for stacking and coupling three-dimensional structures, akin to two-dimensional material-based heterostructures, for enhancing device functionalities8,9.

Thyroid hormone regulates proximodistal patterning in fin rays.

Processes that regulate size and patterning along an axis must be highly integrated to generate robust shapes; relative changes in these processes underlie both congenital disease and evolutionary change. Fin length mutants in zebrafish have provided considerable insight into the pathways regulating fin size, yet signals underlying patterning have remained less clear. The bony rays of the fins possess distinct patterning along the proximodistal axis, reflected in the location of ray bifurcations and the lengths of ray segments, which show progressive shortening along the axis. Here, we show that thyroid hormone (TH) regulates aspects of proximodistal patterning of the caudal fin rays, regardless of fin size. TH promotes distal gene expression patterns, coordinating ray bifurcations and segment shortening with skeletal outgrowth along the proximodistal axis. This distalizing role for TH is conserved between development and regeneration, in all fins (paired and medial), and between Danio species as well as distantly related medaka. During regenerative outgrowth, TH acutely induces Shh-mediated skeletal bifurcation. Zebrafish have multiple nuclear TH receptors, and we found that unliganded Thrab-but not Thraa or Thrb-inhibits the formation of distal features. Broadly, these results demonstrate that proximodistal morphology is regulated independently from size-instructive signals. Modulating proximodistal patterning relative to size-either through changes to TH metabolism or other hormone-independent pathways-can shift skeletal patterning in ways that recapitulate aspects of fin ray diversity found in nature.

Optoelectronic Synapse Based on 2D Electron Gas in Stoichiometry-Controlled Oxide Heterostructures.

Emulating synaptic functionalities in optoelectronic devices is significant in developing artificial visual-perception systems and neuromorphic photonic computing. Persistent photoconductivity (PPC) in metal oxides provides a facile way to realize the optoelectronic synaptic devices, but the PPC performance is often limited due to the oxygen vacancy defects that release excess conduction electrons without external stimuli. Herein, a high-performance optoelectronic synapse based on the stoichiometry-controlled LaAlO3/SrTiO3 (LAO/STO) heterostructure is developed. By increasing La/Al ratio up to 1.057:1, the PPC is effectively enhanced but suppressed the background conductivity at the LAO/STO interface, achieving strong synaptic behaviors. The spectral noise analyses reveal that the synaptic behaviors are attributed to the cation-related point defects and their charge compensation mechanism near the LAO/STO interface. The short-term and long-term plasticity is demonstrated, including the paired-pulse facilitation, in the La-rich LAO/STO device upon exposure to UV light pulses. As proof of concepts, two essential synaptic functionalities, the pulse-number-dependent plasticity and the self-noise cancellation, are emulated using the 5 × 5 array of La-rich LAO/STO synapses. Beyond the typical oxygen deficiency control, the results show how harnessing the cation stoichiometry can be used to design oxide heterostructures for advanced optoelectronic synapses and neuromorphic applications.

Association between substantia nigra degeneration and functional outcome in patients with basal ganglia infarction.

BACKGROUND AND PURPOSE: Cerebral infarction in the basal ganglia may cause secondary and delayed neuronal degeneration in the substantia nigra (SN). However, the clinical significance of SN degeneration remains poorly understood. METHODS: This retrospective observational study included patients with acute ischemic stroke in the basal ganglia on initial diffusion-weighted imaging who underwent follow-up diffusion-weighted imaging between 4 and 30 days after symptom onset. SN degeneration was defined as a hyperintensity lesion in the SN observed on diffusion-weighted imaging. We compared functional outcomes at 3 months between patients with and without SN degeneration. A poor outcome was defined as a score of 3-6 (functional dependence or death) on the modified Rankin Scale. RESULTS: Of 350 patients with basal ganglia infarction (median age = 74.0 years, 53.7% male), 125 (35.7%) had SN degeneration. The proportion of functional dependence or death was 79.2% (99/125 patients) in patients with SN degeneration, which was significantly higher than that in those without SN degeneration (56.4%, 127/225 patients, p < 0.001). SN degeneration was more frequent in patients with functional dependence or death (99/226 patients, 43.8%) than in those with functional independence (26/124 patients, 21.0%, p < 0.001). Multivariable logistic regression analysis showed a significant association between SN degeneration and functional dependence or death (odds ratio = 2.91, 95% confidence interval = 1.17-7.21, p = 0.021). CONCLUSIONS: The study showed that patients with degeneration of SN were associated with functional dependence or death at 3 months, suggesting that secondary degeneration is a predictor of poor stroke outcomes and a potential therapeutic target.

Using Artificial Intelligence to Diagnose Lacrimal Passage Obstructions Based on Dacryocystography Images.

Dacryocystography (DCG) has been used to illustrate the morphological and functional aspects of the lacrimal drainage system in the evaluation of patients with maxillofacial trauma and epiphora. This study developed deep-learning models for the automatic classification of the status of the lacrimal passage based on DCG. The authors collected 719 DCG images from 430 patients with nasolacrimal duct obstruction. The obstruction images were further manually categorized into 2 binary categories based on the location of the obstruction: (1) upper obstruction and (2) lower obstruction. An upper obstruction was defined as one occurring within the canaliculus or common canaliculus, whereas a lower obstruction was defined as one within the lacrimal sac, duct-sac junction, or nasolacrimal duct. The authors then established a deep-learning model to automatically determine whether a passage was patent or obstruction. The accuracy, precision, sensitivity, F1 score, and area under the receiver operating characteristic curve for the evaluation set of each deep-learning model were 99.3%, 98.8%, 99.5%, 99.2%, and 0.9998, respectively, for obstruction detection, and 95.5%, 93.0%, 93.0%, 93.0%, and 0.9778 for classifying the obstruction location. Both receiver operating characteristic curves were skewed toward the left-upper region, indicating the high reliability of these models. The high accuracies of the obstruction detection model (99.3%) and the obstruction classification model (95.5%) demonstrate that deep-learning models can be reliable diagnostic tools for DCG images. This deep-learning model could enhance diagnostic consistency, enable non-specialists to interpret results accurately and facilitate the efficient allocation of medical resources.

Reversible Photomodulation of Two-Dimensional Electron Gas in LaAlO3/SrTiO3 Heterostructures.

Long-lived photoinduced conductance changes in LaAlO3/SrTiO3 (LAO/STO) heterostructures enable their use in optoelectronic memory applications. However, it remains challenging to quench the persistent photoconductivity (PPC) instantly and reproducibly, which limits the reversible optoelectronic switching. Herein, we demonstrate a reversible photomodulation of two-dimensional electron gas (2DEG) in LAO/STO heterostructures with high reproducibility. By irradiating UV pulses, the 2DEG at the LAO/STO interface is gradually transformed to the PPC state. Notably, the PPC can be completely removed by water treatment when two key requirements are met: (1) the moderate oxygen deficiency in STO and (2) the minimal band edge fluctuation at the interface. Through our X-ray photoelectron spectroscopy and electrical noise analysis, we reveal that the reproducible change in the conductivity of 2DEG is directly attributed to the surface-driven electron relaxation in the STO. Our results provide a stepping-stone toward developing optically tunable memristive devices based on oxide 2DEG systems.

Cancer Prediction With Machine Learning of Thrombi From Thrombectomy in Stroke: Multicenter Development and Validation.

BACKGROUND: We aimed to develop and validate machine learning models to diagnose patients with ischemic stroke with cancer through the analysis of histopathologic images of thrombi obtained during endovascular thrombectomy. METHODS: This was a retrospective study using a prospective multicenter registry which enrolled consecutive patients with acute ischemic stroke from South Korea who underwent endovascular thrombectomy. This study included patients admitted between July 1, 2017 and December 31, 2021 from 6 academic university hospitals. Whole-slide scanning was performed for immunohistochemically stained thrombi. Machine learning models were developed using transfer learning with image slices as input to classify patients into 2 groups: cancer group or other determined cause group. The models were developed and internally validated using thrombi from patients of the primary center, and external validation was conducted in 5 centers. The model was also applied to patients with hidden cancer who were diagnosed with cancer within 1 month of their index stroke. RESULTS: The study included 70 561 images from 182 patients in both internal and external datasets (119 patients in internal and 63 in external). Machine learning models were developed for each immunohistochemical staining using antibodies against platelets, fibrin, and erythrocytes. The platelet model demonstrated consistently high accuracy in classifying patients with cancer, with area under the receiver operating characteristic curve of 0.986 (95% CI, 0.983-0.989) during training, 0.954 (95% CI, 0.937-0.972) during internal validation, and 0.949 (95% CI, 0.891-1.000) during external validation. When applied to patients with occult cancer, the model accurately predicted the presence of cancer with high probabilities ranging from 88.5% to 99.2%. CONCLUSIONS: Machine learning models may be used for prediction of cancer as the underlying cause or detection of occult cancer, using platelet-stained immunohistochemical slide images of thrombi obtained during endovascular thrombectomy.

Supramolecular Senolytics via Intracellular Oligomerization of Peptides in Response to Elevated Reactive Oxygen Species Levels in Aging Cells.

Senolytics, which eliminate senescent cells from tissues, represent an emerging therapeutic strategy for various age-related diseases. Most senolytics target antiapoptotic proteins, which are overexpressed in senescent cells, limiting specificity and inducing severe side effects. To overcome these limitations, we constructed self-assembling senolytics targeting senescent cells with an intracellular oligomerization system. Intracellular aryl-dithiol-containing peptide oligomerization occurred only inside the mitochondria of senescent cells due to selective localization of the peptides by RGD-mediated cellular uptake into integrin αvß3-overexpressed senescent cells and elevated levels of reactive oxygen species, which can be used as a chemical fuel for disulfide formation. This oligomerization results in an artificial protein-like nanoassembly with a stable α-helix secondary structure, which can disrupt the mitochondrial membrane via multivalent interactions because the mitochondrial membrane of senescent cells has weaker integrity than that of normal cells. These three specificities (integrin αvß3, high ROS, and weak mitochondrial membrane integrity) of senescent cells work in combination; therefore, this intramitochondrial oligomerization system can selectively induce apoptosis of senescent cells without side effects on normal cells. Significant reductions in key senescence markers and amelioration of retinal degeneration were observed after elimination of the senescent retinal pigment epithelium by this peptide senolytic in an age-related macular degeneration mouse model and in aged mice, and this effect was accompanied by improved visual function. This system provides a strategy for the treatment of age-related diseases using supramolecular senolytics.

Collective Control of Potential-Constrained Oxygen Vacancies in Oxide Heterostructures for Gradual Resistive Switching.

Filamentary resistive switching in oxides is one of the key strategies for developing next-generation non-volatile memory devices. However, despite numerous advantages, their practical applications in neuromorphic computing are still limited due to non-uniform and indeterministic switching behavior. Given the inherent stochasticity of point defect migration, the pursuit of reliable switching likely demands an innovative approach. Herein, a collective control of oxygen vacancies is introduced in LaAlO3 /SrTiO3 (LAO/STO) heterostructures to achieve reliable and gradual resistive switching. By exploiting an electrostatic potential constraint in ultrathin LAO/STO heterostructures, the formation of conducting filaments is suppressed, but instead precisely control the concentration of oxygen vacancies. Since the conductance of the LAO/STO device is governed by the ensemble concentration of oxygen vacancies, not their individual probabilistic migrations, the resistive switching is more uniform and deterministic compared to conventional filamentary devices. It provides direct evidence for the collective control of oxygen vacancies by spectral noise analysis and modeling by Monte-Carlo simulation. As a proof of concept, the significantly-improved analog switching performance of the filament-free LAO/STO devices is demonstrated, revealing potential for neuromorphic applications. The results establish an approach to store information by point defect concentration, akin to biological ionic channels, for enhancing switching characteristics of oxide materials.

QUANTIFIED ANASTOMOTIC AREAS OF NEOVASCULARIZATION AS FACTORS ASSOCIATED WITH FREQUENT RECURRENCE IN NEOVASCULAR AGE-RELATED MACULAR DEGENERATION.

PURPOSE: To investigate the quantitative characteristics of anastomoses of macular neovascularization (MNV) in neovascular age-related macular degeneration using optical coherence tomography angiography according to the frequency of intravitreal injections. METHODS: Eighty-six eyes of 86 patients treated for neovascular age-related macular degeneration were classified into two groups based on the number of intravitreal injections administered over 12 months: stable (<3) and unstable (≥3). Anastomotic areas were defined as areas surrounded by neighboring vessels in the MNV; their total number, mean area, maximal and minimal diameters (i.e., maximal and minimum Feret diameters), and ratio (Feret aspect ratio) were analyzed in the inner and outer areas of the MNV. RESULTS: Forty-four and 42 eyes were classified into the stable and unstable groups, respectively. The eyes in the unstable group had larger anastomotic areas with longer minimum Feret diameters and longer perimeters in the outer MNV. In the logistic regression analysis, instability was associated with a larger anastomotic area and a longer minimum Feret diameter in the outer MNV. Multivariate analysis revealed that a longer minimum Feret diameter in the outer MNV was the most significant factor ( P = 0.03). CONCLUSION: The quantitative characteristics of the anastomotic areas in the MNV might indicate the need for intravitreal injections in patients with neovascular age-related macular degeneration.

Intensive vs Conventional Blood Pressure Lowering After Endovascular Thrombectomy in Acute Ischemic Stroke: The OPTIMAL-BP Randomized Clinical Trial.

Importance: Optimal blood pressure (BP) control after successful reperfusion with endovascular thrombectomy (EVT) for patients with acute ischemic stroke is unclear. Objective: To determine whether intensive BP management during the first 24 hours after successful reperfusion leads to better clinical outcomes than conventional BP management in patients who underwent EVT. Design, Setting, and Participants: Multicenter, randomized, open-label trial with a blinded end-point evaluation, conducted across 19 stroke centers in South Korea from June 2020 to November 2022 (final follow-up, March 8, 2023). It included 306 patients with large vessel occlusion acute ischemic stroke treated with EVT and with a modified Thrombolysis in Cerebral Infarction score of 2b or greater (partial or complete reperfusion). Interventions: Participants were randomly assigned to receive intensive BP management (systolic BP target <140 mm Hg; n = 155) or conventional management (systolic BP target 140-180 mm Hg; n = 150) for 24 hours after enrollment. Main Outcomes and Measures: The primary outcome was functional independence at 3 months (modified Rankin Scale score of 0-2). The primary safety outcomes were symptomatic intracerebral hemorrhage within 36 hours and death related to the index stroke within 3 months. Results: The trial was terminated early based on the recommendation of the data and safety monitoring board, which noted safety concerns. Among 306 randomized patients, 305 were confirmed eligible and 302 (99.0%) completed the trial (mean age, 73.0 years; 122 women [40.4%]). The intensive management group had a lower proportion achieving functional independence (39.4%) than the conventional management group (54.4%), with a significant risk difference (-15.1% [95% CI, -26.2% to -3.9%]) and adjusted odds ratio (0.56 [95% CI, 0.33-0.96]; P = .03). Rates of symptomatic intracerebral hemorrhage were 9.0% in the intensive group and 8.1% in the conventional group (risk difference, 1.0% [95% CI, -5.3% to 7.3%]; adjusted odds ratio, 1.10 [95% CI, 0.48-2.53]; P = .82). Death related to the index stroke within 3 months occurred in 7.7% of the intensive group and 5.4% of the conventional group (risk difference, 2.3% [95% CI, -3.3% to 7.9%]; adjusted odds ratio, 1.73 [95% CI, 0.61-4.92]; P = .31). Conclusions and Relevance: Among patients who achieved successful reperfusion with EVT for acute ischemic stroke with large vessel occlusion, intensive BP management for 24 hours led to a lower likelihood of functional independence at 3 months compared with conventional BP management. These results suggest that intensive BP management should be avoided after successful EVT in acute ischemic stroke. Trial Registration: ClinicalTrials.gov Identifier: NCT04205305.

Association between periodontal disease status and risk of atrial fibrillation: a nationwide population-based cohort study.

BACKGROUND: Periodontal disease can activate an immune process linked to systemic diseases, including atrial fibrillation. However, the relationship between periodontal disease and atrial fibrillation remains unclear. AIM: This study aimed to investigate whether changes in periodontal disease status are associated with the risk of atrial fibrillation. METHODS: Using the National Health Insurance Database Korea, participants who underwent the first oral health examination in 2003 and a second examination in 2005-2006 without a history of atrial fibrillation were included. Participants were grouped according to changes in periodontal disease status during two oral examinations: periodontal disease-free, periodontal disease-recovered, periodontal disease-developed, and periodontal disease-chronic. The outcome was the incidence of atrial fibrillation. RESULTS: The study included 1,254,515 participants, with a median follow-up of 14.3 years and 25,402 (2.02%) cases of atrial fibrillation occurred. During follow-up, the risk of atrial fibrillation was highest in the periodontal disease-chronic group, followed by the periodontal disease-developed, periodontal disease-recovered, and periodontal disease-free groups (p for trend < 0.001). Moreover, recovery from periodontal disease was associated with a reduced risk of atrial fibrillation compared to a chronic periodontal disease status (Hazard ratio: 0.97, 95% Confidence interval: 0.94-0.99, p = 0.045). The development of periodontal disease was associated with an increased risk of atrial fibrillation compared to being periodontal disease-free (Hazard ratio: 1.04, 95% Confidence interval: 1.01-1.08, p = 0.035). CONCLUSION: Our findings suggest that changes in periodontal disease status impact the risk of atrial fibrillation. Management of periodontal disease may help prevent atrial fibrillation.

Accelerated aging phenotypes in the retinal pigment epithelium of Zmpste24-deficient mice.

Age-related macular degeneration (AMD) is a chronic and progressive disease characterized by degeneration of the retinal pigment epithelium (RPE) and retina that ultimately leads to loss of vision. The pathological mechanisms of AMD are not fully known. Cellular senescence, which is a state of cell cycle arrest induced by DNA-damage or aging, is hypothesized to critically affect the pathogenesis of AMD. In this study, we examined the relationship between cellular senescence and RPE/retinal degeneration in mouse models of natural aging and accelerated aging. We performed a bulk RNA sequencing of the RPE cells from adult (8 months old) and naturally-aged old (24 months old) mice and found that common signatures of senescence and AMD pathology - inflammation, apoptosis, and blood vessel formation - are upregulated in the RPE of old mice. Next, we investigated markers of senescence and the degree of RPE/retinal degeneration in Zmpste24-deficient (Zmpste24-/-) mice, which is a model for progeria and accelerated aging. We found that Zmpste24-/- mice display markedly greater level of senescence-related markers in RPE and significant RPE/retinal degeneration compared to wild-type mice, in a manner consistent with natural aging. Overall, these results provide support for the association between cellular senescence of RPE and the pathogenesis of AMD, and suggest the use of Zmpste24-/- mice as a novel senescent RPE model of AMD.

Electron pairing without superconductivity.

Strontium titanate (SrTiO3) is the first and best known superconducting semiconductor. It exhibits an extremely low carrier density threshold for superconductivity, and possesses a phase diagram similar to that of high-temperature superconductors--two factors that suggest an unconventional pairing mechanism. Despite sustained interest for 50 years, direct experimental insight into the nature of electron pairing in SrTiO3 has remained elusive. Here we perform transport experiments with nanowire-based single-electron transistors at the interface between SrTiO3 and a thin layer of lanthanum aluminate, LaAlO3. Electrostatic gating reveals a series of two-electron conductance resonances-paired electron states--that bifurcate above a critical pairing field Bp of about 1-4 tesla, an order of magnitude larger than the superconducting critical magnetic field. For magnetic fields below Bp, these resonances are insensitive to the applied magnetic field; for fields in excess of Bp, the resonances exhibit a linear Zeeman-like energy splitting. Electron pairing is stable at temperatures as high as 900 millikelvin, well above the superconducting transition temperature (about 300 millikelvin). These experiments demonstrate the existence of a robust electronic phase in which electrons pair without forming a superconducting state. Key experimental signatures are captured by a model involving an attractive Hubbard interaction that describes real-space electron pairing as a precursor to superconductivity.

AUTOMATED QUANTIFICATION OF VITREOUS HYPERREFLECTIVE FOCI AND VITREOUS HAZE USING OPTICAL COHERENCE TOMOGRAPHY IN PATIENTS WITH UVEITIS.

PURPOSE: Development of an automated method to quantify the count of vitreous hyperreflective foci (vHF) and intensity of vitreous haze in patients with uveitis by optical coherence tomography. METHODS: A method based on deep learning to automatically segment the vHF, vitreous, and retinal pigment epithelium (RPE) in optical coherence tomography was developed using 1,058 scans from 88 optical coherence tomography volumes of 33 patients with intermediate, posterior or panuveitis. Based on segmented images, the vHF count and the relative intensity of vitreous to RPE (VIT/RPE-relative intensity) were quantified. Dice coefficient and intraclass correlation coefficient were calculated between ground truth and the trained network. RESULTS: The segmented area of vHF, vitreous, and RPE by the deep learning-based model showed good agreement with the clinicians' results, yielding a Dice coefficient of 0.69, 0.99, and 0.88, respectively. The intraclass correlation coefficient of the vHF count and the VIT/RPE-relative intensity per scan was 0.99 and 1.00, respectively. In eyes of test set, changes in vHF and VIT/RPE-relative intensity during treatment did not show similar patterns. CONCLUSION: Automated segmentation of the vHF, vitreous, and RPE in optical coherence tomography images of patients with uveitis was accomplished by a deep learning approach. The vHF count and VIT/RPE-relative intensity could be quantified with high reliability.

POST-TREATMENT PREDICTION OF OPTICAL COHERENCE TOMOGRAPHY USING A CONDITIONAL GENERATIVE ADVERSARIAL NETWORK IN AGE-RELATED MACULAR DEGENERATION.

PURPOSE: To develop a deep learning model to generate posttreatment optical coherence tomography (OCT) images of neovascular age-related macular degeneration. METHODS: Two hundred ninety-eight patients with neovascular age-related macular degeneration were included. The conditional generative adversarial network was trained using 15,183 augmented paired OCT B-scan images obtained from 723 scans of 241 patients at baseline and 1 month after 3 loading doses of an anti-vascular endothelial growth factor treatment. The network was also trained using baseline fluorescein angiography (FA) or indocyanine green angiography (ICGA) images together with baseline OCT images. A test set of 150 images of 50 eyes was used to evaluate its ability to predict the presence of intraretinal fluid, subretinal fluid, PED, and subretinal hyperreflective material. Posttreatment OCT images were compared with images generated from baseline OCT with or without FA and indocyanine green angiography images. RESULTS: The predicted images inferred from baseline OCT images achieved an acceptable accuracy, specificity, and negative predictive value for four lesions (range: 77.0-91.9, 94.1-95.1, and 54.7-96.5%, respectively). The addition of both FA and indocyanine green angiography images improved the accuracy, specificity, and negative predictive value (range: 80.7-96.3, 97.3-99.0, and 59.0-98.3%, respectively). CONCLUSION: A conditional generative adversarial network is able to generate posttreatment OCT images from baseline OCT, FA, and indocyanine green angiography images.

Gate-Tunable Optical Nonlinearities and Extinction in Graphene/LaAlO3/SrTiO3 Nanostructures.

We explore the ultrafast optical response of graphene subjected to intense (∼106 V/cm) local (∼10 nm) electric fields. Nanoscale gating of graphene is achieved using a voltage-biased, SrTiO3-based conductive nanowire junction "written" directly under the graphene and isolated from it by an insulating ultrathin (<2 nm) LaAlO3 barrier. Upon illumination with ultrafast visible-to-near-infrared (VIS-NIR) light pulses, the local field from the nanojunction creates a strong gate-tunable second-order nonlinearity in the graphene and produces a substantial difference-frequency (DFG) and sum-frequency generation (SFG) response detected by the nanojunction. Spectrally sharp, gate-tunable extinction features (>99.9%) are observed in the VIS-NIR and SFG spectral ranges, in parameter regimes that are positively correlated with the enhanced nonlinear response. The observed graphene-light interaction and nonlinear response are of fundamental interest and open the way for future exploitation in graphene-based optical devices such as phase shifters, modulators, and nanoscale THz sources.

Large-Scale Assembly of Peptide-Based Hierarchical Nanostructures and Their Antiferroelectric Properties.

An effective strategy is developed to create peptide-based hierarchical nanostructures through the meniscus-driven self-assembly in a large area and fabricate antiferroelectric devices based on these nanostructures for the first time. The diphenylalanine hierarchical nanostructures (FF-HNs) are self-assembled by vertically pulling a substrate from a diphenylalanine (FF) solution dissolved in a miscible solvent under precisely controlled conditions. Owing to the unique structural properties of FF nanostructures, including high crystallinity and α-helix structures, FF-HNs possess a net electrical dipole moment, which can be switched in an external electric field. The mass production of antiferroelectric devices based on FF-HNs can be successfully achieved by means of this biomimetic assembly technique. The devices show an evident antiferroelectric to ferroelectric transition under dark conditions, while the ferroelectricity is found to be tunable by light. Notably, it is discovered that the modulation of antiferroelectric behaviors of FF-HNs under glutaraldehyde exposure is due to the FF molecules that are transformed into cyclophenylalanine by glutaraldehyde. This work provides a stepping stone toward the mass production of self-assembled hierarchical nanostructures based on biomolecules as well as the mass fabrication of electronic devices based on biomolecular nanostructures for practical applications.

ASSOCIATION OF TREATMENT RESPONSE WITH QUANTITATIVE CHANGES IN CHOROIDAL NEOVASCULARIZATION AND CHOROIDAL VESSEL IN NEOVASCULAR AGE-RELATED MACULAR DEGENERATION.

PURPOSE: To evaluate the association between treatment response and quantitative morphological changes in choroidal neovascularization and outer choroidal vessels using optical coherence tomography angiography (OCTA) and en face OCT in neovascular age-related macular degeneration (nAMD). METHODS: We retrospectively analyzed 75 eyes of typical nAMD patients and 53 polypoidal choroidal vasculopathy eyes of 124 patients with OCTA performed at least 6 months after initial antivascular endothelial growth factor treatment. Quantitative parameters, including vessel area, vessel diameter, branch vessel length, fractal dimension, and lacunarity were analyzed based on en face images of the choroidal neovascularization and choroidal vessel in Haller's layer. Parameters associated with loss of logarithm of the minimum angle of resolution visual acuity with the basis of 0.3 and the treatment interval (good vs. poor responder based on 12 weeks) were analyzed. Analyses were conducted for "before OCTA" (initial visit to OCTA) and "after OCTA" (OCTA to 6 months post-OCTA). RESULTS: In typical nAMD, visual acuity loss before OCTA was associated with a higher SD of choroidal neovascularization diameter and lower choroidal fractal dimension. Visual acuity loss after OCTA in typical nAMD was associated with higher lacunarity of the choroid. Poor responders before OCTA were not associated with any factor. Poor responders after OCTA were associated with a lower SD of outer choroidal vessel diameter in typical nAMD. In polypoidal choroidal vasculopathy, no factor was associated with clinical outcomes in either period. CONCLUSION: Quantitative analyses of choroidal neovascularization on OCTA and choroidal vessels on en face OCT provide information about treatment response, including changes in visual acuity and treatment interval, in nAMD.