Polymer Coatings Affect Transport and Remobilization of Colloidal Activated Carbon in Saturated Sand Columns: Implications for In Situ Groundwater Remediation.

Colloidal activated carbon (CAC) is an emerging technology for the in situ remediation of groundwater impacted by per- and polyfluoroalkyl substances (PFAS). In assessing the long-term effectiveness of a CAC barrier, it is crucial to evaluate the potential of emplaced CAC particles to be remobilized and migrate away from the sorptive barrier. We examine the effect of two polymer stabilizers, carboxymethyl cellulose (CMC) and polydiallyldimethylammonium chloride (PolyDM), on CAC deposition and remobilization in saturated sand columns. CMC-modified CAC showed high mobility in a wide ionic strength (IS) range from 0.1 to 100 mM, which is favorable for CAC delivery at a sufficient scale. Interestingly, the mobility of PolyDM-modified CAC was high at low IS (0.1 mM) but greatly reduced at high IS (100 mM). Notably, significant remobilization (release) of deposited CMC-CAC particles occurred upon the introduction of solution with low IS following deposition at high IS. In contrast, PolyDM-CAC did not undergo any remobilization following deposition due to its favorable interactions with the quartz sand. We further elucidated the CAC deposition and remobilization behaviors by analyzing colloid-collector interactions through the application of Derjaguin-Landau-Verwey-Overbeek theory, and the inclusion of a discrete representation of charge heterogeneity on the quartz sand surface. The classical colloid filtration theory was also employed to estimate the travel distance of CAC in saturated columns. Our results underscore the roles of polymer coatings and solution chemistry in CAC transport, providing valuable guidelines for the design of in situ CAC remediation with maximized delivery efficiency and barrier longevity.

DOVE: Doodled vessel enhancement for photoacoustic angiography super resolution.

Deep-learning-based super-resolution photoacoustic angiography (PAA) has emerged as a valuable tool for enhancing the resolution of blood vessel images and aiding in disease diagnosis. However, due to the scarcity of training samples, PAA super-resolution models do not generalize well, especially in the challenging in-vivo imaging of organs with deep tissue penetration. Furthermore, prolonged exposure to high laser intensity during the image acquisition process can lead to tissue damage and secondary infections. To address these challenges, we propose an approach doodled vessel enhancement (DOVE) that utilizes hand-drawn doodles to train a PAA super-resolution model. With a training dataset consisting of only 32 real PAA images, we construct a diffusion model that interprets hand-drawn doodles as low-resolution images. DOVE enables us to generate a large number of realistic PAA images, achieving a 49.375% fool rate, even among experts in photoacoustic imaging. Subsequently, we employ these generated images to train a self-similarity-based model for super-resolution. During cross-domain tests, our method, trained solely on generated images, achieves a structural similarity value of 0.8591, surpassing the scores of all other models trained with real high-resolution images. DOVE successfully overcomes the limitation of insufficient training samples and unlocks the clinic application potential of super-resolution-based biomedical imaging.

Unexpected metabolic rewiring of CO2 fixation in H2-mediated materials-biology hybrids.

A hybrid approach combining water-splitting electrochemistry and H2-oxidizing, CO2-fixing microorganisms offers a viable solution for producing value-added chemicals from sunlight, water, and air. The classic wisdom without thorough examination to date assumes that the electrochemistry in such a H2-mediated process is innocent of altering microbial behavior. Here, we report unexpected metabolic rewiring induced by water-splitting electrochemistry in H2-oxidizing acetogenic bacterium Sporomusa ovata that challenges such a classic view. We found that the planktonic S. ovata is more efficient in utilizing reducing equivalent for ATP generation in the materials-biology hybrids than cells grown with H2 supply, supported by our metabolomic and proteomic studies. The efficiency of utilizing reducing equivalents and fixing CO2 into acetate has increased from less than 80% of chemoautotrophy to more than 95% under electroautotrophic conditions. These observations unravel previously underappreciated materials' impact on microbial metabolism in seemingly simply H2-mediated charge transfer between biotic and abiotic components. Such a deeper understanding of the materials-biology interface will foster advanced design of hybrid systems for sustainable chemical transformation.

Peak-tracking BOTDA with dynamic ternary search.

We propose a peak-tracking BOTDA (PT-BOTDA) equipped with an efficient dynamic Brillouin frequency shift (BFS) searching scheme based on ternary search. The proposed scheme establishes a feedback loop between the selected frequency and the corresponding Brillouin gain to reduce the required number of scanning frequencies in one measurement. We also demonstrate the performance evaluation of the proposed scheme under scenarios with different searching granularities and dynamic sensing ranges. Experimental results indicate that in all situations, the proposed PT-BOTDA can achieve at least 85% and 97% reduction in the number of scanning frequencies for 1-MHz and 0.1-MHz frequency steps, respectively, with a 3-meter spatial resolution, while maintaining a convincing BFS searching accuracy under sufficient SNR condition using a smaller searching interval.

Effects of Micro-Shot Peening on the Fatigue Strength of Anodized 7075-T6 Alloy.

Micro-shot peening under two Almen intensities was performed to increase the fatigue endurance limit of anodized AA 7075 alloy in T6 condition. Compressive residual stress (CRS) and a nano-grained structure were present in the outermost as-peened layer. Microcracks in the anodized layer obviously abbreviated the fatigue strength/life of the substrate. The endurance limit of the anodized AA 7075 was lowered to less than 200 MPa. By contrast, micro-shot peening increased the endurance limit of the anodized AA 7075 to above that of the substrate (about 300 MPa). Without anodization, the fatigue strength of the high peened (HP) specimen fluctuated; this was the result of high surface roughness of the specimen, as compared to that of the low peened (LP) one. Pickling before anodizing was found to erode the outermost peened layer, which caused a decrease in the positive effect of peening. After anodization, the HP sample had a greater fatigue strength/endurance limit than that of the LP one. The fracture appearance of an anodized fatigued sample showed an observable ring of brittle fracture. Fatigue cracks present in the brittle coating propagated directly into the substrate, significantly damaging the fatigue performance of the anodized sample. The CRS and the nano-grained structure beneath the anodized layer accounted for a noticeable increase in resistance to fatigue failure of the anodized micro-shot peened specimen.

Transparent and Stretchable Au─Ag Nanowire Recording Microelectrode Arrays.

Transparent microelectrodes have received much attention from the biomedical community due to their unique advantages in concurrent crosstalk-free electrical and optical interrogation of cell/tissue activity. Despite recent progress in constructing transparent microelectrodes, a major challenge is to simultaneously achieve desirable mechanical stretchability, optical transparency, electrochemical performance, and chemical stability for high-fidelity, conformal, and stable interfacing with soft tissue/organ systems. To address this challenge, we have designed microelectrode arrays (MEAs) with gold-coated silver nanowires (Au─Ag NWs) by combining technical advances in materials, fabrication, and mechanics. The Au coating improves both the chemical stability and electrochemical impedance of the Au─Ag NW microelectrodes with only slight changes in optical properties. The MEAs exhibit a high optical transparency >80% at 550 nm, a low normalized 1 kHz electrochemical impedance of 1.2-7.5 Ω cm2, stable chemical and electromechanical performance after exposure to oxygen plasma for 5 min, and cyclic stretching for 600 cycles at 20% strain, superior to other transparent microelectrode alternatives. The MEAs easily conform to curvilinear heart surfaces for colocalized electrophysiological and optical mapping of cardiac function. This work demonstrates that stretchable transparent metal nanowire MEAs are promising candidates for diverse biomedical science and engineering applications, particularly under mechanically dynamic conditions.

Dynamic polarization-insensitive BOTDA in direct-detection OFDM with CNN-based BFS extraction.

We propose a dynamic polarization-insensitive Brillouin optical time domain analyzer (D/PI-BOTDA) with orthogonal frequency division multiplexing (OFDM) based on intensity-modulated direct-detection (IM-DD). A polarization-division-multiplexed (PDM) pump signal enables polarization diversity of the stimulated Brillouin scattering while a multi-frequency OFDM probe signal realizes dynamic sensing with single-shot transmission. We experimentally demonstrated distributed temperature sensing along a total 940-meter fiber with a temperature sensing coefficient of 1.2°C/MHz. The experimental results indicated a remarkable suppression of Brillouin gain fluctuation up to 4.38 times compared to the case without polarization diversity. To facilitate the Brillouin frequency shift (BFS) extraction process, we also implement a CNN-based BFS extraction method with SE-Res2Net block. The adopted algorithm achieves a higher accuracy than conventional curve fitting method, with a 10-time enhancement in the time efficiency.

Shortcut to adiabaticity in a silicon polarization splitter rotator using multi-wavelength adiabaticity engineering.

We introduce adiabaticity engineering in coupled waveguide devices to achieve shortcuts to adiabaticity in multi-wavelength systems. By engineering the adiabaticity distribution using a single control parameter, we obtain large operating bandwidth in a compact device. Multi-wavelength adiabaticity engineering is applied to the design of silicon polarization splitter-rotators. The total length of the designed polarization splitter-rotator is 141 µm, and simulations show that the device exhibits extinction ratios above 28 dB and 16 dB for the TE0 and TM0 modes, respectively, with a bandwidth of 300 nm (from 1.4 µm to 1.7 µm). The fabrication tolerance of the designed device is also simulated.

Maximizing light-driven CO2 and N2 fixation efficiency in quantum dot-bacteria hybrids.

Integrating light-harvesting materials with microbial biochemistry is a viable approach to produce chemicals with high efficiency from the air, water, and sunlight. Yet it remains unclear whether all absorbed photons in the materials can be transferred through the material-biology interface for solar-to-chemical production and whether the presence of materials beneficially affect the microbial metabolism. Here we report a microbe-semiconductor hybrid by interfacing CO2/N2-fixing bacterium Xanthobacter autotrophicus with CdTe quantum dots for light-driven CO2 and N2 fixation with internal quantum efficiencies of 47.2 ± 7.3% and 7.1 ± 1.1%, respectively, reaching the biochemical limits of 46.1% and 6.9% imposed by the stoichiometry in biochemical pathways. Photophysical studies suggest fast charge-transfer kinetics at the microbe-semiconductor interfaces, while proteomics and metabolomics indicate a material-induced regulation of microbial metabolism favoring higher quantum efficiencies compared to the biological counterparts alone.

Perfluorocarbon Nanoemulsions Create a Beneficial O2 Microenvironment in N2-fixing Biological | Inorganic Hybrid.

Powered by renewable electricity, biological | inorganic hybrids employ water-splitting electrocatalysis and generate H2 as reducing equivalents for microbial catalysis. The approach integrates the beauty of biocatalysis with the energy efficiency of inorganic materials for sustainable chemical production. Yet a successful integration requires delicate control of the hybrid's extracellular chemical environment. Such an argument is evident in the exemplary case of O2 because biocatalysis has a stringent requirement of O2 but the electrocatalysis may inadvertently perturb the oxidative pressure of biological moieties. Here we report the addition of perfluorocarbon (PFC) nanoemulsions promote a biocompatible O2 microenvironment in a O2-sensitive N2-fixing biological | inorganic hybrid. Langmuir-type nonspecific binding between bacteria and nanoemulsions facilitates O2 transport in bacterial microenvironment and leads to a 250% increase in efficiency for organic fertilizers within 120 hours. Controlling the biological microenvironment with nanomaterials heralds a general approach accommodating the compatibility in biological | inorganic hybrids.

Silver nanoparticles boost charge-extraction efficiency in Shewanella microbial fuel cells.

Microbial fuel cells (MFCs) can directly convert the chemical energy stored in organic matter to electricity and are of considerable interest for power generation and wastewater treatment. However, the current MFCs typically exhibit unsatisfactorily low power densities that are largely limited by the sluggish transmembrane and extracellular electron-transfer processes. Here, we report a rational strategy to boost the charge-extraction efficiency in Shewanella MFCs substantially by introducing transmembrane and outer-membrane silver nanoparticles. The resulting Shewanella-silver MFCs deliver a maximum current density of 3.85 milliamperes per square centimeter, power density of 0.66 milliwatts per square centimeter, and single-cell turnover frequency of 8.6 × 105 per second, which are all considerably higher than those of the best MFCs reported to date. Additionally, the hybrid MFCs feature an excellent fuel-utilization efficiency, with a coulombic efficiency of 81%.

De Novo Approach to Encapsulating Biocatalysts into Synthetic Matrixes: From Enzymes to Microbial Electrocatalysts.

Biocatalysts hold great promise in chemical and electrochemical reactions. However, biocatalysts are prone to inhospitable physiochemical conditions. Encapsulating biocatalysts into a synthetic host matrix can improve their stability and activity, and broaden their operational conditions. In this Review, we summarize the emerging de novo approaches to encapsulating biocatalysts into synthetic matrixes. Here, de novo means that embedding of biocatalysts and construction of matrixes take place simultaneously. We discuss the advantages and limitations of the de novo approach. On the basis of the nature of the biocatalysts and the synthetic frameworks, we specifically focus on two aspects: (1) encapsulation of enzymes (in vitro) in metal-organic frameworks and (2) encapsulation of microbial electrocatalysts (in vivo) on the electrode. For both cases, we discuss how the encapsulation improves biocatalysts' performance (stability, viability, activity, and etc.). We also highlight the benefit of encapsulation in facilitating the transport of charge carriers in microbial electrocatalysis.

AgII -Mediated Electrocatalytic Ambient CH4 Functionalization Inspired by HSAB Theory.

Although most class (b) transition metals have been studied in regard to CH4 activation, divalent silver (AgII ), possibly owing to its reactive nature, is the only class (b) high-valent transition metal center that is not yet reported to exhibit reactivities towards CH4 activation. We now report that electrochemically generated AgII metalloradical readily functionalizes CH4 into methyl bisulfate (CH3 OSO3 H) at ambient conditions in 98 % H2 SO4 . Mechanistic investigation experimentally unveils a low activation energy of 13.1 kcal mol-1 , a high pseudo-first-order rate constant of CH4 activation up to 2.8×103  h-1 at room temperature and a CH4 pressure of 85 psi, and two competing reaction pathways preferable towards CH4 activation over solvent oxidation. Reaction kinetic data suggest a Faradaic efficiency exceeding 99 % beyond 180 psi CH4 at room temperature for potential chemical production from widely distributed natural gas resources with minimal infrastructure reliance.

Overlaying 5G radio access networks on wavelength division multiplexed optical access networks with carrier distribution.

As 5G communication matures, the requirement for advanced radio access networks (RAN) drives the evolution of optical access networks to support these needs. Basic RAN functions, mobile front-haul to the backbone and interconnected front-end remote radio units, must support and enable data rate surges, low-latency applications, RF coordination, etc. Wavelength division multiplexed optical access networks (WDM-OANs) provide sufficient network capacity to support the addition of RAN services, especially in unused portions of WDM. We propose and demonstrate a method for RAN overlay in WDM-OANs that employ distributed carriers. In such systems, the carrier is modulated at the central office for direct-detected downstream digital data services; later the same carrier is remodulated for the uplink. We propose the use of silicon photonics to intercept the downstream and add 5G signals. We examine the distributed-carrier power budget issues in this overlay scenario. The carrier power must be harvested for direct detection of both digital and RoF services, and yet hold in reserve sufficient power for the uplink remodulation of all services. We concentrate on the silicon photonics subsystem at the remote node to add RoF signals. We demonstrate the overlay with a fabricated chip and study strategic allocations of carrier power at the optical network units housing the radio units to support the overlay. After the successful drop and reception of both conventional WDM-OAN and the newly overlaid RoF signals, we demonstrate sufficient carrier power margin for the upstream remodulation.

Isolated interrupted aortic arch in an adult: A case report.

BACKGROUND: Interrupted aortic arch (IAA) is a rare congenital heart disease defined by an interruption of the lumen and anatomical continuity between the ascending and descending major arteries. It is usually found within a few hours or days of birth. Without surgery, the chances of survival are low. If IAA patients have an effective collateral circulation established, they can survive into adulthood. However, IAA in adults is extremely rare, with few reported cases. CASE SUMMARY: A 27-year-old woman presented with a 6-year history of progressively worsening shortness of breath and chest tightness on exertion. She had cyanotic lips and clubbing of the fingers. A transthoracic echocardiogram revealed an enlarged heart and dilation of the main pulmonary artery. There was an abnormal 9 mm passage between the descending aorta and pulmonary artery. The ventricular septal outflow tract had a 14 mm defect. Doppler ultrasound suggested a patent ductus arteriosus and computed tomographic angiography showed the absence of the aortic arch. The diagnoses were ventricular septal defect, patent ductus arteriosus, and definite interruption of the aortic arch. Although surgical correction was recommended, the patient declined due to the surgical risks and was treated with medications to reduce pulmonary artery pressure and treat heart failure. Her condition has been stable for 12 mo of follow-up. CONCLUSION: Although rare, IAA should be considered in adults with refractory hypertension or unexplained congestive heart failure.

Manipulated Optical Absorption and Accompanied Photocurrent Using Magnetic Field in Charger Transfer Engineered C/ZnO Nanowires.

The rarely explored, spin-polarized band engineering, enables direct dynamic control of the magneto-optical absorption (MOA) and associated magneto-photocurrent (MPC) by a magnetic field, greatly enhancing the range of applicability of photosensitive semiconductor materials. It is demonstrated that large negative and positive MOA and MPC effects can be tuned alternately in amorphous carbon ( a-C )/ZnO nanowires by controlling the sp2/sp3 ratio of a-C . A sizeable enhancement of the MPC ratio (≈15%) appears at a relatively low magnetic field (≈0.2 T). Simulated two peaks spin-polarized density of states is applied to explain that the alternate sign switching of the MOA is mainly related to the charge transfer between ZnO and C. The results indicate that the enhanced magnetic field performance of ( a-C )/ZnO nanowires may have applications in renewable energy-related fields and tunable magneto-photonics.

Electricity-powered artificial root nodule.

Root nodules are agricultural-important symbiotic plant-microbe composites in which microorganisms receive energy from plants and reduce dinitrogen (N2) into fertilizers. Mimicking root nodules using artificial devices can enable renewable energy-driven fertilizer production. This task is challenging due to the necessity of a microscopic dioxygen (O2) concentration gradient, which reconciles anaerobic N2 fixation with O2-rich atmosphere. Here we report our designed electricity-powered biological|inorganic hybrid system that possesses the function of root nodules. We construct silicon-based microwire array electrodes and replicate the O2 gradient of root nodules in the array. The wire array compatibly accommodates N2-fixing symbiotic bacteria, which receive energy and reducing equivalents from inorganic catalysts on microwires, and fix N2 in the air into biomass and free ammonia. A N2 reduction rate up to 6.5 mg N2 per gram dry biomass per hour is observed in the device, about two orders of magnitude higher than the natural counterparts.

Synthesis of 2D Layered BiI3 Nanoplates, BiI3 /WSe2 van der Waals Heterostructures and Their Electronic, Optoelectronic Properties.

Two-dimensional layered materials (2DLMs) have attracted considerable recent interest as a new material platform for fundamental materials science and potential new technologies. Here we report the growth of layered metal halide materials and their optoelectronic properties. BiI3 nanoplates can be readily grown on SiO2 /Si substrates with a hexagonal geometry, with a thickness in the range of 10-120 nm and a lateral dimension of 3-10 µm. Transmission electron microscopy and electron diffraction studies demonstrate that the individual nanoplates are high quality single crystals. Micro-Raman studies show characteristic Ag band at ≈115 cm-1 with slight red-shift with decreasing thickness, and micro-photoluminescence studies show uniform emission around 690 nm with blue-shift with decreasing thickness. Electrical transport studies of individual nanoplates show n-type semiconductor characteristics with clear photoresponse. Further, the BiI3 can be readily grown on other 2DLMs (e.g., WSe2 ) to form van der Waals heterostructures. Electrical transport measurements of BiI3 /WSe2 vertical heterojunctions demonstrate p-n diode characteristics with gate-tunable rectification behavior and distinct photovoltaic effect. The synthesis of the BiI3 nanoplates can expand the library of 2DLMs and enable a wider range of van der Waals heterostructures.

Physical-layer network coding for passive optical interconnect in datacenter networks.

We introduce physical-layer network coding (PLNC) technique in a passive optical interconnect (POI) architecture for datacenter networks. The implementation of the PLNC in the POI at 2.5 Gb/s and 10Gb/s have been experimentally validated while the gains in terms of network layer performances have been investigated by simulation. The results reveal that in order to realize negligible packet drop, the wavelengths usage can be reduced by half while a significant improvement in packet delay especially under high traffic load can be achieved by employing PLNC over POI.

Growth of Single-Crystalline Cadmium Iodide Nanoplates, CdI2/MoS2 (WS2, WSe2) van der Waals Heterostructures, and Patterned Arrays.

Two-dimensional layered materials (2DLMs) have attracted considerable recent interest for their layer-number-dependent physical and chemical properties, as well as potential technological opportunities. Here we report the synthesis of two-dimensional layered cadmium iodide (CdI2) nanoplates using a vapor transport and deposition approach. Optical microscopy and scanning electron microscopy studies show that the resulting CdI2 nanoplates predominantly adopt hexagonal and triangular morphologies with a lateral dimension of ∼2-10 µm. Atomic force microscopy studies show that the resulting nanoplates exhibit a thickness in the range of 5-220 nm with a relatively smooth surface. X-ray diffraction studies reveal highly crystalline CdI2 in hexagonal phase, which is also confirmed by the characteristic Raman Ag mode at 110 cm-1. High-resolution transmission electron microscopy and selected area electron diffraction reveal that the resulting CdI2 nanoplates are single crystals. Taking a step further, we show the CdI2 nanoplates were readily grown on other 2DLMs (e.g., WS2, WSe2, MoS2), forming diverse van der Waals heterostructures. Using prepatterned WS2 monolayer square arrays as the nucleation and growth templates, we also show that regular arrays of CdI2/WS2 vertical heterostructures can be prepared. The synthesis of the CdI2 nanoplates, heterostructures, and heterostructure arrays offers a valuable material system for 2D materials science and technology.