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Analysis of the intensive phase of biowaste composting process with the addition of sour buttermilk
Abstract The sustainable management of dairy industry waste remains a major environmental challenge, particularly for sour buttermilk, which is characterized by low pH and high concentrations of slowly degradable biogenic compounds. Its discharge to wastewater treatment systems contradicts circular economy principles and highlights the need for alternative valorization pathways. In this research, the feasibility of incorporating waste sour buttermilk into green biomass during composting was evaluated, and its effects on the intensive phase, selected physicochemical and microbiological properties, and the phytotoxicity of the resulting material were assessed. Sour buttermilk was applied at proportions ranging from 0 to 30% (w/w). Its addition reduced ammonia concentrations in emitted gases from maximum values exceeding 1000 ppm in the control to approximately 600–700 ppm in treatments with 9% and higher additions. At levels above 6%, the addition of sour buttermilk limited the extent of drying during the thermophilic phase. However, additions exceeding 12% adversely affected process performance, as thermophilic conditions (> 45 °C) were achieved only briefly and at relatively low temperatures. This inhibition was associated with decreased pH, increased moisture content, and reduced air-filled porosity. Higher application rates also increased the phytotoxicity of the obtained materials. No potentially pathogenic bacteria were detected in any treatment. Overall, the results indicate that controlled incorporation of sour buttermilk may influence composting dynamics, with 9% (w/w) showing the most balanced process performance under the tested conditions.
Site-dependent defect formation and evolution in 4H-silicon carbide: A molecular dynamics study
Displacement cascades induced by ion implantation are a crucial process for fabricating color centers in 4H-silicon carbide, while the differences in defect formation and evolution at hexagonal and cubic lattice sites are often overlooked. In this study, molecular dynamics simulations were employed to systematically investigate the site-dependent formation and evolution of point defects and divacancies in 4H-silicon carbide. The results indicate that the stable number of displaced atoms at cubic sites is significantly higher than that at hexagonal sites, primarily driven by carbon displaced atoms, whereas vacancy concentrations show no substantial site difference. This behavior is attributed to the lower threshold displacement energy of cubic carbon atoms (∼30.19 eV) relative to hexagonal carbon atoms (∼33.31 eV), together with a site-exchange recombination process amplifying the displaced-atom disparity while narrowing the vacancy disparity. Moreover, the divacancies generated during the initial cascades are highly unstable, with approximately 80% undergoing recombination. Among the surviving stable divacancies, the production of basal configurations is significantly higher than that of axial configurations. This study provides critical data for developing site-resolved radiation damage models in 4H-SiC and offers valuable microscopic theoretical insights into the fabrication of solid-state quantum color centers via ion irradiation.
At the boundary: Law and AI
Recapitulating gestational progression: a high-throughput 3D bioprinted vascularized human placenta demonstrating stage-specific molecular and functional signatures of human pregnancy
Abstract The placenta is a highly dynamic organ that supports the growth and development of the fetus during gestation. Malfunction of the placenta causes disorders of the pregnancy, including preeclampsia and pre-term birth. The study of the pathophysiology of the placenta throughout pregnancy has been hindered by limited access to the human placenta and lack of predictive cellular and animal models. Here, we describe 3D bioprinted human placenta barrier (hPB) tissue models using primary human trophoblasts and stroma cells that recapitulate the physiology of the human placenta at early and late stages of gestation. These bioprinted vascularized hPB tissue models mimic the architecture and function early and late-stages human placenta, including barrier function, nutrient uptake, transporters activity and hormones secretion. Assembled in a 96-well transwell plate format, this deeply characterized platform provides a robust high-fidelity system for predictive screening of therapeutics and potentially hazardous agents for placenta diseases and safety, and a better understanding of placental pathophysiology.
Mechanism of strain-modulated photonic spin Hall effect in Td-WTe2
Weyl semimetals (WSMs) provide a promising platform for exploring strain modulation of the photonic spin Hall effect (PSHE) because of their topologically nontrivial band structures and strongly anisotropic optical responses. To clarify how strain modulates the PSHE through the optical response of WSMs, a first-principles-based strain–optical conductivity–PSHE framework was established, and a non-contact strain-measurement PSHE-based scheme was proposed. For this purpose, the type-II WSM Td-WTe2 was chosen as the study object, and density functional theory, Wannier interpolation, and the linear-response Kubo formalism were integrated to analyze the complex optical conductivity tensor, the Fresnel coefficients, and the resulting photonic spin Hall displacement. Under monochromatic illumination, the dependence of the photonic spin Hall displacement on incident angle and uniaxial strain was obtained by scanning incident angles from 30° to 90° and strains from −5% to +5%. The calculations showed that introducing Td-WTe2 at the reflection interface gave rise to a pronounced peak–valley pair within a narrow angular range. The angular positions of these features remained nearly unchanged, whereas their amplitudes varied systematically with strain. The strain-modulation mechanism was clarified by tracing the strain-dependent evolution of the conductivity tensor and its transfer, through the Fresnel response, to the photonic spin Hall displacement. Based on this relation, strain was quantitatively retrieved from the photonic spin Hall displacement measured at a fixed incident angle. This scheme provided a physics-based solution for optical strain analysis and measurement in anisotropic WSMs.
Echolocating bats sacrifice binaural localization cues for target-focused hearing during high-speed foraging
Accurate sound localization is critical to navigation and foraging in echolocating animals. During both passive listening and active echolocation, bats are thought to rely solely on interaural level differences (ILDs) between the two ears, attaining very large ILDs by orienting their outer ears apart. However, detecting weak prey echoes during high-speed foraging should instead favor target-focused pinnae that maximize sonar range and reduce clutter interference. Therefore, we propose that flying bats orient their pinnae toward prey. We test this hypothesis using a unique wind tunnel and by employing deep-learning-facilitated high-speed stereo photogrammetry and show that freely flying bats indeed orient their pinnae forward, directly on target. This produces large spatial overlap between each ear’s receiving beams, markedly reducing ILDs, and rejects the hypothesis that bats rely solely on ILDs for localization in flight. Instead, bats achieve a highly directional acoustic field of view through coordinated alignment of the emitted and received sonar beams, which amplifies the central acoustic axis and attenuates off-axis echoes. Parallel to visual object tracking, flying bats likely prioritize signal-to-noise ratio, trading off large ILDs for clutter-filtering and sonar range, which allows them to use very weak echoes and simplify their self-generated auditory scene. We hypothesize that this highly directional acoustic field of view aids in localization, potentially in combination with interaural time differences, in the absence of large ILDs. This envisions an inherently simplified acoustic scene that better accounts for how bats hunt efficiently in complex environments.
Phytochemical profiling, antioxidant activity, and allelopathic potential of Jatropha podagrica Hook. leaf extract and fractions
Bending and vibration of nanoplates: Symmetry lowering and surface elastic effects
In this study, we investigate the bending and vibration of nanoplates under the coupled effects of surface elasticity, residual surface stress, symmetry lowering, and additional elastic constants. A significant size dependence is observed for the maximum deflections and natural frequencies at nanoscale. Increasing nanoplate thickness reduces surface effects and restores symmetry, causing deflections and frequencies to converge to the conventional Kirchhoff plate limit. Si 〈100〉 oriented nanoplates with various surface reconstructions were adopted as examples. In all cases except the (2 × 1)-type reconstruction on both surfaces, the maximum deflection not only decreases in magnitude but also reverses direction. The resultant positive residual stresses, resulting from specific combinations of surface reconstruction on the upper and lower surfaces, can increase the nanoplate's deflection and vibration frequency, while negative values have the opposite effect. The resultant negative residual stresses, arising from surface reconstruction on the upper and lower surfaces, are a more critical factor influencing the bending characteristics than surface elasticity and symmetry lowering, whereas the reverse holds for resultant positive residual stresses. A decrease in the maximum deflection is associated with both a reduction in resultant residual stresses and an increase in bending stiffness. Due to the reduced influence of surface effects and symmetry lowering on higher-order vibration modes, the normalized natural frequency of the nanoplates tends to a stable value in higher-order modes.
Refinement of robot-assisted nipple-sparing mastectomy utilizing the da Vinci SP system and SP access port device: the RASPB-1 Pilot Trial
Comprehensive analysis of the anisotropic dielectric response of wurtzite (0001¯)Sc <i>x</i> Al1− <i>x</i> N for 0.1 ≤ <i>x</i> ≤ 0.3
We present evaluation and detailed modeling of the anisotropic dielectric response of single-phase, (0001¯) oriented wurtzite (wz) ScxAl1−xN films employing spectroscopic ellipsometry (SE) in a spectral range from 0.037 to 6.5 eV. The samples were grown by plasma-assisted molecular-beam epitaxy and cover a composition range from 0.1 ≤ x ≤ 0.3. Clear signatures of the extraordinary dielectric function are observed in the SE data, providing evidence that the anisotropy is accessible from (0001¯) oriented films in this case. We obtain both the ordinary and extraordinary dielectric functions from point-by-point and parametric model fits, respectively. In the ultraviolet spectral range, we find negative and significantly different bowing parameters for ordinary and extraordinary absorption edges, resulting in an enormous increase in the crystal field splitting. In the infrared spectral range, a linear decrease in phonon frequency is observed for transverse optical and longitudinal optical phonons of E1 (ordinary) and A1 (extraordinary) symmetry, consistent with the linear increase in crystal volume. Finally, we derive estimates for dielectric constants, Born-effective charges, and the spontaneous polarization. We find that the dielectric limits and Born-effective charges increase, while the spontaneous polarization decreases with increasing x.
Legal infrastructure for transformative AI governance
Most of our AI governance efforts focus on substance: What rules do we want in place? What limits or checks do we want to impose on AI development and deployment? But a key role for law is not only to establish substantive rules but also to establish legal and regulatory infrastructure to generate and implement rules. The transformative nature of AI calls especially for attention to building legal and regulatory frameworks. In this Perspective, I review three examples: the creation of registration regimes for frontier models; the creation of registration and identification regimes for autonomous agents; and the design of regulatory markets to facilitate a role for private companies to innovate and deliver AI regulatory services.
Multi-objective optimization of a hybrid photovoltaic–thermal energy system under load demand uncertainties using Bat algorithm
Enhancing laser-induced damage threshold of picosecond laser mirrors using graded-refractive-index multilayer structures
Graded-refractive-index (n) multilayer architectures are examined as a means of improving the laser-induced damage threshold (LIDT) of picosecond laser mirrors. The Al2O3 and Al2O3/HfO2 nano-laminates are employed as high-n materials to form a mirror structure, where the n values of the high-n layers gradually increase along the direction of the electric-field attenuation. Compared with a conventional M-Constant mirror based on a fixed-n Al2O3–HfO2 mixture, the M-Graded mirror shows a 1.49-fold increase in LIDT under picosecond laser irradiation, while the reflection bandwidth above 99.5% reflectivity decreases by only ∼6.9%. Observation of laser-induced damage sites indicates that damage initiation is mainly associated with nanoscale absorbing defects on the coating surface, suggesting that redistribution of the material composition profile through graded-refractive-index multilayers helps suppress damage and improve the LIDT of high-power picosecond laser mirrors.
LARP1 at the nexus of oncogenic MYC and mTOR signaling
Wearable near-infrared photoimmunotherapy using a flexible LED sheet light device
Effective parameters for dielectric waveguides and resonators in linear and nonlinear regimes
Modern waveguiding structures contain various materials that extend their properties beyond mere waveguiding. Here, the most common cases are considered: materials with linear loss or gain and Kerr-type nonlinearity. A convenient and insightful description of how guided waves are affected by these materials is to recast their properties into material parameters and electromagnetic modal parameters, giving rise to the concept of effective parameters, e.g., geometrical loss factor, gain confinement factor, effective modal area, and effective nonlinear refractive index. The literature contains abundant formulas for the effective parameters. At times, they are applied beyond their range of validity, scope of applicability, or are even incorrect. Here, key effective parameters are consistently derived and corresponding formulas from the literature are discussed. This Tutorial serves two purposes. First, it guides the reader step-by-step through the derivation of waveguide and resonator characteristics, introduces effective parameters, and discusses related issues. Second, it provides formulas for many practical situations for the reader more interested in using them directly for specific calculations, such as analyzing experimental data or making theoretical predictions, without delving into mathematical details. This also applies to choosing correct parameters in commercial software packages.
The backfiring effect of weak AI safety regulation
Recent policy proposals aim to improve the safety of general-purpose AI, but there is little understanding of the efficacy of different regulatory approaches. We present a strategic model that explores interactions between safety regulation, general-purpose AI technology creators, and domain specialists—those who adapt the technology for specific applications. Our analysis examines how regulatory measures targeting different parts of the AI development chain affect the outcome of this game. Our model assumes AI technology is characterized by two key attributes: safety and performance. The regulator first sets a minimum safety requirement that applies to one or both players. The general-purpose creator then invests in the technology, establishing its initial safety and performance levels. Next, domain specialists refine the AI for their use cases, updating the safety and performance levels and taking the product to market. Resulting revenue is shared between the specialist and generalist. Our analysis reveals two insights: first, weak safety regulation imposed predominantly on domain specialists can backfire. While it might seem logical to regulate AI use cases, our analysis shows that weak regulations targeting domain specialists alone can reduce safety in a large class of parameterizations. Second, in contrast to the previous finding, we observe that stronger, well-placed regulation can mutually benefit all players. When regulators impose appropriate safety standards on both general-purpose AI creators and domain specialists, the regulation can function as a commitment device, leading to safety and performance gains, surpassing what is achievable under no regulation or regulating only one player.
FractureAgent: a multi-tool LLM-based intelligent agent for personalized fracture rehabilitation management
Effect of aqueous sulfide treatments on HgCdTe surface after KI-based polishing for MWIR FPA fabrication
In this work, aqueous sulfide passivation of Hg1−xCdxTe (x = 0.29) surfaces was systematically investigated using a combination of spectroscopic and electrical techniques. Time-dependent treatments in ammonium sulfide [(NH4)2Sx], sodium sulfide (Na2S), and thioacetamide (CH3CSNH2) were examined by ellipsometry and x-ray photoelectron spectroscopy (XPS) on the epilayers. Ellipsometry measurements confirmed the formation of a uniform sulfide film upon (NH4)2Sx treatment, with an average thickness of ∼6.5 nm and a refractive index of 2.6 after 30 min of exposure. XPS spectra revealed the progressive replacement of surface oxides (TeO2, CdTeO3, and HgTeO3) by stable sulfide compounds (HgS and CdS), indicating stabilization of the HgCdTe interface. Overall, the results demonstrate that 30 min of (NH4)2Sx treatment produces an optimally passivated HgCdTe surface, characterized by minimal oxides, uniform sulfide coverage, and superior electrical stability. These findings highlight the potential of sulfur passivation for improving the performance and reliability of HgCdTe-based infrared detectors. Metal–insulator–semiconductor (MIS) capacitors in the form CdS/CdTe/ZnS/Cr–Au MIS were subsequently fabricated, and high-frequency C–V measurements at 80 K were performed to evaluate the electrical stability of the passivated interfaces. The results identify a 30 min (NH4)2Sx treatment leading to an electrolytic growth of CdS, followed by CdTe/ZnS deposition as an effective route for reducing oxide content at the interface, supporting its use in achieving a stable HgCdTe interface suitable for high-performance infrared device applications.