Machine-learning potentials for nanoscale simulations of deformation and fracture: example of TiB2_2 ceramic

Machine-learning interatomic potentials (MLIPs) offer a powerful avenue for simulations beyond length and timescales of ab initio methods. Their development for investigation of mechanical properties and fracture, however, is far from trivial since extended defects -- governing plasticity and crack nucleation in most materials -- are too large to be included in the training set. Using TiB$_2$ as a model ceramic material, we propose a strategy for fitting MLIPs suitable to simulate mechanical response of monocrystals until fracture. Our MLIP accurately reproduces ab initio stresses and failure mechanisms during room-temperature uniaxial tensile deformation of TiB$_2$ at the atomic scale ($\approx{10}^3$ atoms). More realistic tensile tests (low strain rate, Poisson's contraction) at the nanoscale ($\approx{10}^4$--10$^6$ atoms) require MLIP up-fitting, i.e. learning from additional ab initio configurations. Consequently, we elucidate trends in theoretical strength, toughness, and crack initiation patterns under different loading directions. To identify useful environments for further up-fitting, i.e., making the MLIP applicable to a wider spectrum of simulations, we asses transferability to other deformation conditions and phases not explicitly trained on

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

First-principles calculation of thermal transport properties driven by the ferro- and antiferroelectric phase transition : A comprehensive study for ABC structures

Previous research expected the ABC (G1-G2-G15) compounds to have similar ferroelectricity with perovskite compounds, but there is a lack of research about their thermal transport properties, which are essential for practical application. Based on the Density Functional Theory (DFT), their lattice thermal conductivities (kappaL) are calculated in this study by using the Self-Consistent Phonon Method (SCP) combined with the Compressive Sensing (CS) approach. Using LiBeP, NaMgBi, NaMgP, and LiMgP as target examples, their structural, electronic, and thermal transport properties changes between ferro- and anti-ferroelectric phase transitions are calculated. The anti-ferroelectric to the ferroelectric phase transition increases the bulk kappaL of LiBeP and NaMgBi by 53% and 17% at 300 K, respectively. By contrast, the bulk kappaL of NaMgP exhibits a decreasing rate of 42%. Among the four materials in the polar phase, their bulk kappaL order from highest to lowest is LiBeP, LiMgP, NaMgP, and NaMgBi. Remarkably, the bulk kappaL of polar LiBeP (25.5 W/mK) is 5 times larger than the rest three materials in polar phases (around 4.9 W/mK). With temperature increasing from 250 to 900 K, the bulk kappaL of LiBeP, NaMgBi, and LiMgP are reduced by 68%, 64% and 55%, respectively. From 250 to 450 K caused by a different converged range, it of NaMgP decreases 57%. Moreover, the comparison of the harmonic and anharmonic methods indicates that the anharmonic method hosts higher physical rationality for ABC compounds. By analyzing the structural parameters, mode-level properties (phonon lifetime, group velocity, Grüneisen parameter), and electronic properties (band structure, electron localization function), the reasons for the kappaL change under different phases and temperatures are explained with details in terms of anisotropy, anharmonicity, scattering, and covalent bonding

Editable Neural Radiance Fields Convert 2D to 3D Furniture Texture

Our work presents a neural network designed to convert textual descriptions into 3D models. By leveraging the encoder-decoder architecture, we effectively combine text information with attributes such as shape, color, and position. This combined information is then input into a generator to predict new furniture objects, which are enriched with detailed information like color and shape.[1] The predicted furniture objects are subsequently processed by an encoder to extract feature information, which is then utilized in the loss function to propagate errors and update model weights. After training the network, we can generate new 3D objects solely based on textual input, showcasing the potential of our approach in generating customizable 3D models from descriptive text.[2

An EHBP-1-SID-3-DYN-1 axis promotes membranous tubule fission during endocytic recycling.

The ACK family tyrosine kinase SID-3 is involved in the endocytic uptake of double-stranded RNA. Here we identified SID-3 as a previously unappreciated recycling regulator in the Caenorhabditis elegans intestine. The RAB-10 effector EHBP-1 is required for the endosomal localization of SID-3. Accordingly, animals with loss of SID-3 phenocopied the recycling defects observed in ehbp-1 and rab-10 single mutants. Moreover, we detected sequential protein interactions between EHBP-1, SID-3, NCK-1, and DYN-1. In the absence of SID-3, DYN-1 failed to localize at tubular recycling endosomes, and membrane tubules breaking away from endosomes were mostly absent, suggesting that SID-3 acts synergistically with the downstream DYN-1 to promote endosomal tubule fission. In agreement with these observations, overexpression of DYN-1 significantly increased recycling transport in SID-3-deficient cells. Finally, we noticed that loss of RAB-10 or EHBP-1 compromised feeding RNAi efficiency in multiple tissues, implicating basolateral recycling in the transport of RNA silencing signals. Taken together, our study demonstrated that in C. elegans intestinal epithelia, SID-3 acts downstream of EHBP-1 to direct fission of recycling endosomal tubules in concert with NCK-1 and DYN-1

Data analysis between controllable variables and the performance of CuS crackle based electrode

In this article, we provide the data analysis between controllable variables and the performance of CuS crackle based electrode, there are four important factors which could influence the formation of cracks, the colloid concentration, drying temperature, colloid dosage and ambient humidity. We carried out and summed nineteen controlled data experiments below and other variates which could affect the performance were discussed in this article

Cerebral Autoregulation Status in Relation to Brain Injury on Electroencephalogram and Magnetic Resonance Imaging in Children Following Cardiac Surgery

Background Disturbed cerebral autoregulation has been reported in children with congenital heart disease before and during cardiopulmonary bypass surgery, but not after. We sought to characterize the cerebral autoregulation status in the early postoperative period in relation to perioperative variables and brain injuries. Methods and Results A prospective and observational study was conducted in 80 patients in the first 48 hours following cardiac surgery. Cerebral oximetry/pressure index (COPI) was retrospectively calculated as a moving linear correlation coefficient between mean arterial blood pressure and cerebral oxygen saturation. Disturbed autoregulation was defined as COPI >0.3. Correlations of COPI with demographic and perioperative variables as well as brain injuries on electroencephalogram and magnetic resonance imaging and early outcomes were analyzed. Thirty‐six (45%) patients had periods of abnormal COPI for 7.81 hours (3.38 hours) either at hypotension (median 90 mm Hg) or both. Overall, COPI became significantly lower over time, suggesting improved autoregulatory status during the 48 postoperative hours. All of the demographic and perioperative variables were significantly associated with COPI, which in turn was associated with the degree of brain injuries and early outcomes. Conclusions Children with congenital heart disease following cardiac surgery often have disturbed autoregulation. Cerebral autoregulation is at least partly the underlying mechanism of brain injury in those children. Careful clinical management to manipulate the related and modifiable factors, particularly arterial blood pressure, may help to maintain adequate cerebral perfusion and reduce brain injury early after cardiopulmonary bypass surgery. Further studies are warranted to determine the significance of impaired cerebral autoregulation in relation to long‐term neurodevelopment outcomes

Inducing long lasting B cell and T cell immunity against multiple variants of SARS-CoV-2 through mutant bacteriophage Qβ – receptor binding domain conjugate

More than two years into the global pandemic, SARS-CoV-2 remains a significant threat to public health. Immunities acquired from infection or current vaccines fail to provide long term protection against subsequent infections, mainly due to their fast-waning nature and the emergence of variants of concerns (VOCs) such as Omicron. To overcome these limitations, SARS-CoV-2 Spike protein receptor binding domain (RBD)-based epitopes were investigated as conjugates with a powerful carrier, the mutant bacteriophage Qβ (mQβ). The epitope design was critical to eliciting potent antibody responses with the full length RBD being superior to peptide and glycopeptide antigens. The full length RBD with orientation-controlled conjugation with mQβ activated both humoral and cellular immune systems in vivo, inducing broad spectrum, persistent and comprehensive immune responses effective against multiple VOCs including Delta and Omicron variants, rendering it a promising vaccine candidate

Cu(II)-Doped Polydopamine-Coated Gold Nanorods for Tumor Theranostics

Gold nanorods (AuNRs) are potentially useful in tumor theranostics, but the poor stability, high toxicity, and rapid removal by the immune system seriously limit their theranostic applications. In our study, we demonstrate the fabrication of Cu­(II)-doped polydopamine-coated AuNR (AuNR@CuPDA), which significantly improves the potentials in tumor theranostics. Besides the improvement of physiological stability and biocompatibility, the PDA shell increases the photothermal performance and prolongs the blood circulation time of AuNRs. The half-life of AuNRs during blood circulation increases from 0.7 to 4.5 h after PDA coating, and the injected dose per gram of tumor tissue is 4.6% ID g^–1 for AuNR@CuPDA. In addition to computer tomography imaging, the loading of Cu­(II) in PDA shell endows AuNR@CuPDA with magnetic resonance imaging function. Cu­(II) doped in PDA shell also exhibits chemotherapeutic behavior, and the tumor inhibitor rate is 31.2%. Further combining 808 nm laser-driven photothermal therapy, tumors were completely ablated, and no recurrence was observed. Liver and renal functions tests and histological analysis of major organs confirm that AuNR@CuPDA is in good safety