Spectrum of Temperature-Dependent Rotational Frequency of the Rotor in a Thermally Diven Rotary Nanomotor

By fixing of the outer tube of double-walled carbon nanotubes, a thermally driven rotary nanomotor can be obtained one or more carbon atoms at the end of the stator have an obvious inward radial deviation. Due to the asymmetry of the potential field of the stator, a collision between two tubes leads to the axial component of angular momentum that drives the rotation of the rotor. Relative sliding between the two tubes is resisted due to the roughness of the potential field of stators. Hence, the rotational frequency of the rotor has a maximal value in the balanced state. The spectrum of rotational frequency with respect to temperatures from 8 to 2000 K is presented by means of molecular dynamics simulation. The temperature interval is divided into five zones on the basis of the characteristics of the spectrum. In the robust zone, the nanomotor exhibits stationary rotation. In the controllable zone, the rotational frequency of rotor can be adjusted by varying the temperature. In particular, if a rotating rotor is cooled to an ultralow temperature, the final stable value of the rotational frequency is still very high and is slightly lower than the maximal value rather than zero; i.e., the nanomotor will theoretically never stop rotating

Over-Speeding Rotational Transmission of a Carbon Nanotube-Based Bearing

In studying the rotational transmission behavior of a carbon nanotube-based bearing (e.g., (5, 5)/(10, 10)) driven by a CNT motor (e.g., (9, 9)) at finite temperature, one can find that the rotor has different dynamic states from the motor at different environmental condition. In particular, the rotor can be in the overspeeding rotational transmission (ORT) state, in which the rotational speed of the rotor is higher than that of the motor. If we change the rotational frequency of the motor (e.g., >100 GHz) and the curved angle of the rotor, the bearing can reach the ORT state. Besides, in the ORT state, the ratio of the rotor’s rotational speed over that of the motor will be not higher than the ratio of the motor’s radius over that of the rotor. There are two major reasons that result in the bearing to the ORT state. One is that the thermal vibration of atoms between the carbon–hydrogen (C–H) end of the motor and that of the rotor has a drastic collision when the motor is in a high rotational speed. The collision causes the atoms at the end of the rotor to have a circular and axial velocity. The circular velocity leads to the rotation of the rotor and the axial velocity causes the oscillation of the rotor. Another reason is sourced from the oblique angle between the rotor and the stators due to the rotor having a curved angle. A higher oblique angle results in higher friction between the rotor and stator, and it also provides higher collision between the rotor and motor. Hence, one can adjust the transmission state of the rotor by changing not only the environmental temperature but also the rotational speed of the motor, as well as the curved angle of the rotor. The mechanism is essential in guiding a design of a rotational transmission nanodevice which transforms the rotation of the motor into other states of the rotor as output signals

Self-Assembly of a Jammed Black Phosphorus Nanoribbon on a Fixed Carbon Nanotube

Nanotube synthesizing from black phosphorus (BP) is still challenging in laboratory. Fabricating a BP nanotube by self-assembling of a BP nanoribbon seems promising. To estimate the feasibility of such fabrication method, this study performs numerical experiments of self-assembling a jammed BP ribbon on a fixed carbon nanotube using molecular dynamics simulation. The study is based on the following two facts: The phosphorus–phosphorus (P–P) bond is weaker than the bond of carbon–carbon (C–C) and the van der Waals interaction among nonbonding phosphorus atoms is stronger than that between phosphorus atoms and carbon atoms. The results show that when a longer BP ribbon is jammed by a shorter BP ribbon the self-assembling result depends on the relative positions of carbon nanotube (CNT) and the two BP ribbons. Only when the shorter BP ribbon is on the outside of the longer ribbon can the longer BP ribbon be wound on the CNT to form an ideal BP nanotube. The finding is helpful for practical applications of BP nanotubes in nanodevices

Data_Sheet_1_Genetic evidence strengthens the bidirectional connection between gut microbiota and Shigella infection: insights from a two-sample Mendelian randomization study.ZIP

BackgroundIn recent investigations, substantial strides have been made in the precise modulation of the gut microbiota to prevent and treat a myriad of diseases. Simultaneously, the pressing issue of widespread antibiotic resistance and multidrug resistance resulting from Shigella infections demands urgent attention. Several studies suggest that the antagonistic influence of the gut microbiota could serve as a novel avenue for impeding the colonization of pathogenic microorganisms or treating Shigella infections. However, conventional research methodologies encounter inherent challenges in identifying antagonistic microbial agents against Shigella, necessitating a comprehensive and in-depth analysis of the causal relationship between Shigella infections and the gut microbiota.Materials and methodsUtilizing the aggregated summary statistics from Genome-Wide Association Studies (GWAS), we conducted Mendelian Randomization (MR) analyses encompassing 18,340 participants to explore the interplay between the gut microbiota and Shigella infections. This investigation also involved 83 cases of Shigella infection patients and 336,396 control subjects. In the positive strand of our findings, we initially performed a preliminary analysis using the Inverse Variance Weighting (IVW) method. Subsequently, we undertook sensitivity analyses to assess the robustness of the results, addressing confounding factors’ influence. This involved employing the Leave-One-Out method and scrutinizing funnel plots to ensure the reliability of the MR analysis outcomes. Conclusively, a reverse MR analysis was carried out, employing the Wald ratio method due to the exposure of individual Single Nucleotide Polymorphisms (SNPs). This was undertaken to explore the plausible associations between Shigella infections and genetically predicted compositions of the gut microbiota.ResultsIn this study, we employed 2,818 SNPs associated with 211 species of gut microbiota as instrumental variables (IVs). Through IVW analysis, our positive MR findings revealed a significant negative correlation between the occurrence of Shigella infections and the phylum Tenericutes (OR: 0.18, 95% CI: 0.04–0.74, p = 0.02), class Mollicutes (OR: 0.18, 95% CI: 0.04–0.74, p = 0.02), genus Intestinimonas (OR: 0.16, 95% CI: 0.04–0.63, p = 0.01), genus Gordonibacter (OR: 0.39, 95% CI: 0.16–0.93, p = 0.03), and genus Butyrivibrio (OR: 0.44, 95% CI: 0.23–0.87, p = 0.02). Conversely, a positive correlation was observed between the occurrence of Shigella infections and genus Sutterella (OR: 10.16, 95% CI: 1.87–55.13, p = 0.01) and genus Alistipes (OR: 12.24, 95% CI: 1.71–87.34, p = 0.01). In sensitivity analyses, utilizing MR-Egger regression analysis and MR Pleiotropy Residual Sum and Outlier (MR-PRESSO) detection, all outcomes demonstrated robust stability. Simultaneously, in the reverse MR analysis, Shigella infections resulted in an upregulation of four bacterial genera and a downregulation of three bacterial genera.ConclusionIn summation, the MR analysis outcomes corroborate the presence of bidirectional causal relationships between the gut microbiota and Shigella infections. This study not only unveils novel perspectives for the prevention and treatment of Shigella infections but also furnishes fresh insights into the mechanistic underpinnings of how the gut microbiota contributes to the pathogenesis of Shigella infections. Consequently, the established dual causal association holds promise for advancing our understanding and addressing the complexities inherent in the interplay between the gut microbiota and Shigella infections, thereby paving the way for innovative therapeutic interventions and preventive strategies in the realm of Shigella-related diseases.</p

Hypersensitive Detection and Quantitation of BoNT/A by IgY Antibody against Substrate Linear-Peptide

<div><p>Botulinum neurotoxin A (BoNT/A), the most acutely poisonous substance to humans known, cleave its SNAP-25 substrate with high specificity. Based on the endopeptidase activity, different methods have been developed to detect BoNT/A, but most lack ideal reproducibility or sensitivity, or suffer from long-term or unwanted interferences. In this study, we developed a simple method to detect and quantitate trace amounts of botulinum neurotoxin A using the IgY antibody against a linear-peptide substrate. The effects of reaction buffer, time, and temperature were analyzed and optimized. When the optimized assay was used to detect BoNT/A, the limit of detection of the assay was 0.01 mouse LD₅₀ (0.04 pg), and the limit of quantitation was 0.12 mouse LD₅₀/ml (0.48 pg). The findings also showed favorable specificity of detecting BoNT/A. When used to detect BoNT/A in milk or human serum, the proposed assay exhibited good quantitative accuracy (88% < recovery < 111%; inter- and intra-assay CVs < 18%). This method of detection took less than 3 h to complete, indicating that it can be a valuable method of detecting BoNT/A in food or clinical diagnosis.</p> </div

Effects of buffer in the ALc endopeptidase assay.

<p>A) The concentration–response relations between OD₄₅₀ and ALc with different buffer combinations. B buffer: 0.02 M Na₃PO₄, 0.5 M NaCl, 0.4 M imidazole, pH 7.4; PBS buffer: 0.008 M NaH₂PO₄, 0.002 M Na₂HPO₄, 0.145 M NaCl, pH 7.2; PB buffer: 0.008 M d NaH₂PO₄, 0.002 M Na₂HPO₄, pH 7.2. B) Sensitivity of endopeptidase assay in different buffer combinations.</p

Single- and Double-Layer Structures and Sorption Properties of Two Microporous Metal–Organic Frameworks with Flexible Tritopic Ligand

Two 2D multifunctional microporous metal–organic frameworks, [Cd₃(L)₂(H₂O)₆]·1.5H₂O·2EtOH·DMF (<b>1</b>, H₃L = 2,4,6-tris-(4-carboxyphenoxy)-1,3,5-triazine) and [Zn₃(L)₂(H₂O)₂]·3H₂O·TEA·2DMF (<b>2</b>), with single- and double-(6,3)-layer structures, respectively, have been synthesized by the reaction of Cd­(Zn) nitrate with H₃L in a mixed solvent of DMF, ethanol, and H₂O. TGA and PXRD analysis showed that compounds <b>1</b> and <b>2</b> were thermally stable up to 250 °C. Gas sorption measurement indicates that compounds <b>1</b> and <b>2</b> exhibited selective sorption capabilities for CO₂ over CH₄ and N₂ and could adsorb considerable amounts of H₂ at low temperature. These two compounds also showed high sorption capabilities for water, methanol, and ethanol vapors. The highest adsorption amounts of compounds <b>1</b> and <b>2</b> are 168.8 and 257.3 cc/g for H₂O, 175.1 and 140.8 cc/g for methanol, and 91.7 and 76.2 cc/g for ethanol, respectively. Furthermore, the maximum luminescence emission peaks of compounds <b>1</b> and <b>2</b> exhibit blue shifts of 138 and 132 nm, respectively, compared to the free ligand

SDS-PAGE results of purified SNAP25 and ALc, as well as cleaved SNAP25 by BoNT/A and ALc.

<p>A) SDS-PAGE result of purified SNAP25. M: marker; 1: purified SNAP25. B) SDS-PAGE result of purified ALc. M: marker; 1: purified ALc. C) SDS-PAGE result of purified SNAP25 mixed with ALc. M: marker; 1: 10 µl of SNAP25; 2: 10 µl of SNAP25 + 5 µl of ALc; 3: 10 µl of SNAP25 + 10 µl of ALc; 4: 10 µl of SNAP25 + 15 µl of ALc; 5: 10 µl of SNAP25 + 20 µl of ALc.</p

Single- and Double-Layer Structures and Sorption Properties of Two Microporous Metal–Organic Frameworks with Flexible Tritopic Ligand

Two 2D multifunctional microporous metal–organic frameworks, [Cd₃(L)₂(H₂O)₆]·1.5H₂O·2EtOH·DMF (<b>1</b>, H₃L = 2,4,6-tris-(4-carboxyphenoxy)-1,3,5-triazine) and [Zn₃(L)₂(H₂O)₂]·3H₂O·TEA·2DMF (<b>2</b>), with single- and double-(6,3)-layer structures, respectively, have been synthesized by the reaction of Cd­(Zn) nitrate with H₃L in a mixed solvent of DMF, ethanol, and H₂O. TGA and PXRD analysis showed that compounds <b>1</b> and <b>2</b> were thermally stable up to 250 °C. Gas sorption measurement indicates that compounds <b>1</b> and <b>2</b> exhibited selective sorption capabilities for CO₂ over CH₄ and N₂ and could adsorb considerable amounts of H₂ at low temperature. These two compounds also showed high sorption capabilities for water, methanol, and ethanol vapors. The highest adsorption amounts of compounds <b>1</b> and <b>2</b> are 168.8 and 257.3 cc/g for H₂O, 175.1 and 140.8 cc/g for methanol, and 91.7 and 76.2 cc/g for ethanol, respectively. Furthermore, the maximum luminescence emission peaks of compounds <b>1</b> and <b>2</b> exhibit blue shifts of 138 and 132 nm, respectively, compared to the free ligand

Single- and Double-Layer Structures and Sorption Properties of Two Microporous Metal–Organic Frameworks with Flexible Tritopic Ligand

Two 2D multifunctional microporous metal–organic frameworks, [Cd₃(L)₂(H₂O)₆]·1.5H₂O·2EtOH·DMF (<b>1</b>, H₃L = 2,4,6-tris-(4-carboxyphenoxy)-1,3,5-triazine) and [Zn₃(L)₂(H₂O)₂]·3H₂O·TEA·2DMF (<b>2</b>), with single- and double-(6,3)-layer structures, respectively, have been synthesized by the reaction of Cd­(Zn) nitrate with H₃L in a mixed solvent of DMF, ethanol, and H₂O. TGA and PXRD analysis showed that compounds <b>1</b> and <b>2</b> were thermally stable up to 250 °C. Gas sorption measurement indicates that compounds <b>1</b> and <b>2</b> exhibited selective sorption capabilities for CO₂ over CH₄ and N₂ and could adsorb considerable amounts of H₂ at low temperature. These two compounds also showed high sorption capabilities for water, methanol, and ethanol vapors. The highest adsorption amounts of compounds <b>1</b> and <b>2</b> are 168.8 and 257.3 cc/g for H₂O, 175.1 and 140.8 cc/g for methanol, and 91.7 and 76.2 cc/g for ethanol, respectively. Furthermore, the maximum luminescence emission peaks of compounds <b>1</b> and <b>2</b> exhibit blue shifts of 138 and 132 nm, respectively, compared to the free ligand