Cavity Size Research Articles

Accurate computation of gas binding in the nanoscale porous organic cage CC3 via coupled cluster theory.

This study investigates the binding of seven gas molecules-N2, CH4, C2H2, CO2, H2O, SF6, and CHCl3-within the central cavity of the nanoscale porous organic cage CC3, using a high-level local coupled cluster method that accounts for single, double, and perturbative triple excitations, extrapolated to the complete basis set limit. This results in the formation of the CC3@7 dataset, which presents unique challenges due to the need for accurate descriptions of confinement effects and many-body interactions that contribute to binding. The CC3@7 dataset is used to evaluate a variety of lower-cost computational approaches. Among the methods tested for accurately predicting the binding order for all seven gas molecules, the recommended MP2-based approach is MP2+aiD(CCD), which achieves a mean absolute error (MAE) of 0.4 kcal/mol. For density functional theory (DFT) methods, B97M-V+EABC, B97M-V, M06-L-D3, B97M-rV+EABC, PBE0+D4, and PBE+D4 are recommended, with MAEs ranging from 0.3 to 0.4 kcal/mol. Additionally, r2SCAN-3c and ωB97X- 3c are identified as low-cost options, with MAEs of approximately 1 kcal/mol. Considering both accuracy and stability, PBE0+D4 is recommended for investigating nanoscale host-guest bindings when only DFT methods are feasible. Furthermore, PBE0+D4 has been successfully applied to study the binding of additional atoms and hindered solvent molecules, demonstrating the flexibility of the CC3 cage to accommodate larger molecules that exceed its cavity size.

Lithographically defined cavities with high Quality and Purcell factors

Abstract We introduce and analyze a lithographically defined cavity (Li-cavity) incorporating a buried mesa defect in a planar vertical structure, which induces transverse photonic confinement while enabling compatibility with electrical injection. We systematically investigate the influence of key cavity parameters on optical behavior and fundamental properties using a comprehensive three-dimensional optical model. Our analysis reveals that the Li-cavity exhibits low optical scattering, resulting in high Q and Purcell factors, even at sub-wavelength dimensions. Furthermore, the Li-cavity supports single-mode operation within a broader aperture size range compared to conventional cavity designs, promising enhanced optical power of single-mode emission. Adequately designed structures demonstrate superior Q and Purcell factors at wavelength scale sizes,- outperforming conventional micropillar cavities. These improved properties and customizable device characteristics stem from a simple fabrication process that precisely controls the cavity size, shape, and optical mode. Superior characteristics, along with its adaptability to diverse materials, wavelengths, and photonic integration platforms, promise a broad range of applications and potential adaptation of this design to diverse photonic devices.

Experimental analysis of rock mass transport during dolomite and gas outburst

In this paper, the problem of transporting rock material deep into the working is addressed. In the case of coal, literature reports indicate that sorbed gas is responsible for coal mass transport. As a result of laboratory tests, the marginality of sorption phenomena occurring in dolomite was confirmed. Transport of rock material during rock and gas outburst takes place in several stages. In the first stage, the post-outburst masses by gravity onto the bottom of the excavation and gas is released from the cavern which, after reaching a critical speed, entrains the accumulated material. A study was carried out to estimate the minimum start-up speed for grain transport. On the basis of analyses of the occurring gas-geodynamic phenomena and the conducted experimental tests, it can be concluded that on the basis of the size of the post-throw cavity and the length of the retention of the post-outburst masses, the work of transporting the post-outburst masses can be estimated. Finally, an energy balance of the rock-gas outburst phenomenon was performed based on the rock-gas system parameters estimated after two outbursts in dolomite.

Association of the Genotype of TNFα with the Efficiency of the Intensive Phase of Chemotherapy and Formation of the Sizes of Destruction Cavities in Patients with Pulmonary Tuberculosis.

The interrelation between the TNFα gene polymorphism and the effectiveness of the intensive phase of chemotherapy in patients with pulmonary tuberculosis, as well as the formation of diameter of the sizes of destruction cavities was studied. It was revealed that the most adverse course of the disease and a high frequency of formation of destruction cavities are associated with the GG genotype of the TNFα gene.

Ultrathin cyclodextrin-based nanofiltration membrane with tunable microporosity for antibiotic desalination

Nanofiltration (NF) membranes play a crucial role in ion separation and antibiotic purification due to their energy efficiency and environment-friendliness. However, conventional polymeric membranes are susceptible to the “trade-off” between permeability and selectivity due to the lack of intrinsically rigid micropores. Herein, the amino-cyclodextrins (amino-CDs) with different cavity sizes were synthesized and employed as the building block to construct 15-nm-thick nanofilms. The rational incorporation of macrocycles with well-defined and tunable cavity into nanofilm enabled a significant enhancement of water permeance and a precise manipulation of molecular weight cut-off of the membranes. Thanks to the significant difference of inherent energy barrier for passage of ions through CD cavity, the CD-incorporated membranes achieved a high Cl−/SO42− selectivity of 87. In addition, the CD-regulated membranes showed an excellent antibiotic desalination performance, out-performing the state-of-the-art membranes for antibiotic purification. This work provides a gateway to the development of nanofiltration membranes with precise molecular sieving for antibiotic desalination.

Tunable diode laser absorption spectroscopy monitoring of the water vapor condensation process in the high-speed flow

Abstract In this work, non-invasive high-precision quantitative measurements of the water vapor condensation process have been carried out using tunable diode laser absorption spectroscopy(TDLAS) at the sub-millisecond level. The high-speed condensation of water vapor is achieved by a self-designed rarefaction wave reflection system. Combined with different sizes of experimental cavities, the condensation process is realised at various time scales of sub-milliseconds (0.2-0.66 ms). The processes of temperature and water vapor content during the high-speed condensation are measured using the water vapor absorption spectra near 7168.437 cm-1 and 7185.597 cm^-1. The experimental results show that the hypervelocity expansion flow field generated by the experimental system demonstrates good uniformity and reaches a cooling rate of 10^5 K/s, which has the same order as that of the supersonic nozzle. The condensation process is similar on different sub-millisecond timescales and the normalised temperature change curves are approximately the same. Moreover, the higher the water vapor content, the shorter the condensation time.

Enhancing the Chemical Stability of P12L24 Cage: Transformation of the Chemically Labile Imine Cage into a Robust Carbamate Cage.

Herein, we report enhancement in chemical stability of the imine-based porphyrinic cage P12L24 by converting it into a robust carbamate porphyrinic cage, c-P12L24, through a two-step post-synthetic modification process. First, the imine bonds in P12L24 were reduced to form an amine-based cage, r-P12L24, followed by carbamation using N,N'-carbonyldiimidazole (CDI) to yield c-P12L24. The resulting carbamate cage exhibits high stability under acidic and basic conditions (pH 1-13) and in the presence of moisture. 1H NMR, DOSY NMR, and DFT calculations revealed that reducing the imine bonds to amine increases the framework's flexibility, causing partial structural collapse, whereas the carbamate formation restores structural rigidity. The insertion of a 4.0 nm molecular ruler into the cavity of zinc-metallated c-P12L24 via metal-ligand coordination further confirmed restoration of the cavity size and geometry of the original cage. This enhancement of chemical stability through carbamate formation can pave the way to a wide range of potential applications for the gigantic porphyrinic cage.

Kratom Alkaloids: A Blood-Brain Barrier Specific Membrane Permeability Assay-Guided Isolation and Cyclodextrin Complexation Study.

Mitragynine is an "atypic opioid" analgesic with an alternative mechanism of action and a favorable side-effect profile. Our aim was to optimize the alkaloid extraction procedure from kratom leaves and to determine and isolate the most relevant compounds capable of penetrating the central nervous system. The PAMPA-BBB study revealed that mitragynine and its coalkaloids, speciociliatine, speciogynine, and paynantheine, possess excellent in vitro BBB permeability. An optimized sequence of CPC, flash chromatography, and preparative HPLC methods was used to isolate the four identified BBB+ alkaloids. To improve the bioavailability of the isolated alkaloids, their cyclodextrin (CD) complexation behavior was investigated via affinity capillary electrophoresis using almost 40 CD derivatives. The apparent alkaloid-CD complex stability constants were determined and compared, and the most relevant CDs phase-solubility studies were also performed. Both the neutral and negatively charged derivatives were able to form complexes with all four kratom alkaloids. It was found that cavity size, substituent type, and degree of substitution also influenced complex formation. The negatively charged Sugammadex, Subetadex, and the sufoalkylated-beta-CD analogs were able to form the most stable complexes, exceeding 1000 M-1. These results serve as a good basis for further solubility and stability enhancement studies of kratom alkaloids.

Peridynamics simulations of the damage of reinforced concrete structures under radial blasting

Concrete is prone to damage under explosive loads, which can cause a large number of casualties and property losses. The concrete fragmentation process during explosion is transient and dynamic, and the experimental measurement of such events is difficult and risky to conduct, and the intermediate explosion process is difficult to observe in the experimental tests. Therefore, the numerical simulation is an ideal method to model and simulate the explosion process of concrete. Different from the traditional finite element method, Peridynamics (PD) method uses the spatial integral equation to replace the traditional local differential equation to solve the fragmentation problem with massive and complex discontinuous patterns. In this study, a peridynamics (PD) model is developed to simulate the failure process of reinforced concrete (RC) structures under radial blasting. Concrete PD models with different cavity sizes and reinforcement conditions were established and calibrated with the experimental data. We find that the crack growth and damage pattern obtained in the peridynamics simulation is consistent with the experiment test results, which verifies the feasibility of peridynamics method as a modeling tool for modeling concrete damage under explosive load and for evaluating anti-explosion performance of RC concrete structures.

Numerical Simulation on the Influence of the Distribution Characteristics of Cracks and Solution Cavities on the Wellbore Stability in Carbonate Formation

The development of cracks and solution cavities in carbonate reservoirs can notably reduce the rock’s mechanical properties, leading to a severe wellbore collapse problem during drilling operations. To clarify the influence of the characteristics of cracks and solution cavities on the wellbore stability in the Dengying Formation carbonate reservoir in the Gaoshiti–Moxi area of Sichuan, the mechanical properties of carbonate rock were analyzed. Then, the influences of the attitude and width of cracks, the size and quantity of solution cavities, and their connectivity on wellbore stability were studied using FLAC3D 6.00 numerical simulation software. Our results show the following: (1) The cracks and solution cavities in the Dengying Formation carbonate rock cause significant differences in the rock’s mechanical properties. (2) The equivalent drilling fluid density of collapse pressure (ρc) considering the effects of cracks and solution cavities is 6.4% higher than without these effects, which is in good accordance with engineering practice. Additionally, cracks play a more significant role than solution cavities in affecting the wellbore stability. (3) When the orientation of a crack is closer to the direction of maximum horizontal stress, and the dip angle and width of the crack increase, the stress and deformation at the intersection of the crack and wellbore gradually increase, and correspondingly, ρc also increases. (4) The stress and displacement of various points around the solution cavities gradually increase with the increases in diameter and quantity of solution cavities, and ρc also increases. (5) Compared with the situation where cracks and solution cavities are not interconnected, the stress disturbance area around the wellbore is larger, and ρc is greater when cracks and solution cavities are interconnected.

Comparative clinical evaluation of correct anatomic contour and tight contact in Class II direct composite restoration using two newer contact forming instruments

Aim: The aim of the study was to compare and evaluate proximal contact tightness and contours using two newer contact-forming systems in Class II composite restorations. Materials and Methods: After institutional ethical approval and Clinical Trials Registry-India registration, patients were chosen according to the inclusion-exclusion criteria with informed consent. A total of 60 patients were randomly assigned to two groups. Group A: LM Arte contact former (n = 30) and Group B: The design village (TDV) contact former (n = 30). Quadrant isolation was performed after the complete elimination of dental caries, preceded by the insertion of a matrix band and retainer with the proper wedging system. The LM Arte with the appropriate tip was selected for Group A, whereas the TDV contact former was selected for Group B based on the cavity size. Following the conversion of Class II cavities to Class I, nanohybrid resin composite restoration was done by cuspal layering. It was followed by finishing and polishing. E. B. Hencock criteria were used to evaluate gingival index, pocket depth, interproximal calculus, overhangs, food impaction, and contact integrity in both groups at baseline, 6 months, and 1 year. Statistical Methods: The data were analyzed using the Chi-Square test with SPSS (Statistical Package for Social Sciences) software version 18.0, IBM. Results: A statistically significant reduction in gingival index score was observed in both groups 6 months and 1 year after the procedure. However, the values revealed in terms of gingival index (P < 0.05) and (P > 0.05) for pocket depth, interproximal calculus, overhangs, food impaction, and contact integrity in both groups for 6 months (P > 0.05) and (P > 0.05) after the procedure. Conclusion: Both the LM Arte and TDV contact-forming systems are effective in establishing perfect proximal contacts and contours. However, the LM Arte contact-forming system edges out the TDV contact-forming system.

Exploring optimal methods for age-at-death estimation using pulp/tooth area ratios: a South African study.

Age-at-death estimation is pivotal in the identification of unknown human decedents in forensic medicine. The pulp/tooth area ratio (PAR) method, assessing pulp cavity size as a marker of secondary dentine apposition, is widely utilised for adult age estimation. Despite extensive evaluation of this technique, the influence of image type and enamel area inclusion on method accuracy is insufficiently explored. The present study evaluated the PAR method's applicability using maxillary canines from a South African cadaveric sample, examining reliability, sex bias, and accuracy across different image types and enamel area considerations. An observational, cross-sectional study design was followed. Fifty-two adult maxillary canines were radiographed, sectioned, and analysed using stereomicroscopy. Labiolingual and mesiodistal periapical radiographs, alongside labiolingual stereomicroscopic tooth section images, were analysed using ImageJ to calculate PARs. Age estimation linear regression models were developed for each image type, with and without enamel area inclusion. Models were compared for performance and accuracy using best-subsets regression and cross-validation analyses. Results indicated that the PAR method is a reliable, sex-independent technique, providing relatively accurate age-at-death estimates for South African adults. Image type significantly influenced accuracy, with tooth section images exhibiting the best/lowest error values, followed by labiolingual and mesiodistal radiographs, respectively. Exclusion of enamel area consistently enhanced model performance across all image types. This study contributes valuable data to the underexplored field of dental age estimation techniques for South African adults, highlighting optimal approaches when applying the PAR method to maxillary canines. Additionally, it introduces a refined stereomicroscopic technique, augmenting and enhancing existing practices.

Defect-controlled confined growth of nano-MOFs to prepare materials with hierarchical micro/mesoporous structures for efficient CO2 capture

In recent years, nanoporous materials with special structure have been widely used in various fields. In view of the poor stability of MOFs materials and the poor mass transfer ability, in this study, we developed a simple method to restrict the growth of UiO-66-NH2 crystals in hollow silica by “vacuum evaporation” strategy, different kinds of acid regulators were introduced, to obtain a composite material with hierarchical pore structure. By characterizing the physical chemistry and microstructure of the composite adsorbent, and calculating the structural defects under different acid regulation, the adsorption and desorption performance and stability of the adsorbent for CO2 were comprehensively investigated. The mechanism of action on CO2 was further analyzed by in-situ infrared and other techniques. The results show that the change of coordination environment and coordination rate caused by the competition of organic acids, which increases the defects and reduces the nucleation and aggregation effect of UiO-66-NH2, promotes the formation of hierarchical pore structure of the composites. Among them, benzoic acid is the best regulating monocarboxylic acid, which makes UiO-66-NH2 have good dispersion in the cavity and suitable crystal size. The specific surface area of the composite material is 717.96 m2 g−1. At the same time, due to its excellent CO2 adsorption capacity (3.35 mmol g−1) at 298 K and 1.06 bar, it is 48.07 % higher than the original UiO-66-NH2. In order to accomplish the goal of effective CO2 adsorption performance of composites, this study offers a novel approach for the synthesis and modification of MOFs-based composites.

Investigation of the melting and solidification processes of a phase change material in cylindrical annular enclosures: A parametric study for energy densification in hot water tanks

The present study focuses on the analysis of the effect of the phase change material (PCM) cavity size on the melting and solidification processes for application to thermal energy densification in a hot water tank through latent heat thermal energy storage in cylindrical annular cavities. A 2D axisymmetric composite geometrical pattern is considered, formed by a phase change material surrounded by a conductive and an insulating material. A parametric study is conducted on the phase change material cavity size, and the results are presented using non-dimensional numbers: Fourier number, Rayleigh number, and aspect ratio. Two approaches have been developed based on local and global analyses. The local one showed the predominance of the conductive or convective heat transfer process concerning the influence of the phase change material size, and thus the Rayleigh number, on the evolution of the solid/liquid interface and streamline shapes. The global one allowed correlations for melting and solidification Fourier numbers with respect to the Rayleigh number and aspect ratio to be built from simulation data. Two parameters for each process have been identified and defined from the present study: the critical Fourier number and the aspect ratio constant. The critical Fourier number corresponds to the maximum Fourier number that the phase change material needs to achieve for a melting or solidification process. The aspect ratio constant provides information on the phase change material aspect ratio value where the Rayleigh number no longer influences the process. In the case of the melting process, this parameter is an indication that convection has reached a maximum intensity and no longer influences the process. Finally, this study proposes a suitable aspect ratio for optimizing the melting process: 19.32, and another for optimizing the solidification process: 16.29.

Exploring the criterion for the self-pulsing suppression of mid-IR intracavity OPO with self-Raman scattering.

The stimulated Raman scattering (SRS) from the Nd:YVO4 gain medium is originally employed to eliminate the self-pulsing effect from the intracavity optical parametric oscillator (OPO) for achieving a continuous-wave (CW) mid-infrared output. The SRS with a second-order pump-wave power depletion is applied as the damping for the coupling between OPO pump-wave relaxation oscillation and signal-wave depletion. The SRS threshold conditions for different cavity and diode-pumped mode size designs are theoretically and experimentally explored. By using different resonators, the CW mid-infrared output from 120 mW to 1.56 W at the diode pump power from 3 to 19.3 W can be successfully demonstrated.

Mode selective damping behavior of additively manufactured beam structures

AbstractAdditive manufacturing, with its inherent process-related degrees of freedom, offers significant potential for manufacturing high-performance parts. This allows effects to be integrated that enable completely new solution mechanisms for existing conflicting objectives, which means that the degrees of design freedom make it possible to optimize the application-specific behavior of a part. In addition to the thermal or electrical properties, the dynamic behavior of a part can also be optimized, for example. This article focuses on the integration of the particle damping effect, which can contribute significantly to increased part damping. Unfused powder inside the part leads to energy dissipation through impact and friction mechanisms. However, the particle damping effect is not yet fully explored, lacking essential knowledge for application in product design. Therefore, test specimens with particle dampers, manufactured using laser powder bed fusion by laser beam from 1.2709 tool steel, are investigated, with variations in the position and size of the particle-filled cavities. To determine damping, the samples are freely supported and excited with an impulse. The damping ratio is calculated based on the recorded decay behavior. The results show an increase in damping ratio of up to a factor of 70, with the extent of improvement strongly dependent on the cavity’s volume and, crucially, its position relative to the part’s mode shape. A linear relationship between the damping ratio and the displacement of the volume of the cavities of the beams is shown.

Diversity of heart failure phenotypes in transthyretin amyloid cardiomyopathy. More than just heart failure with preserved ejection fraction

Introduction Current guidelines recommend suspecting transthyretin amyloid cardiomyopathy (ATTR-CM) in patients over 65 years of age with unexplained left ventricular (LV) hypertrophy in a non-dilated LV, heart failure (HF) and preserved ejection fraction (HFpEF), hypertrophic cardiomyopathy or severe aortic stenosis. However, there is evidence indicating a high prevalence of ATTR-CM in other HF phenotypes. As such, this study aimed to characterize the diversity of HF phenotypes of ATTR-CM by examining the LV ejection fraction and LV dilatation using echocardiography. Methods This multicentre, retrospective observational study included patients diagnosed with ATTR-CM between 2015–2023. The diagnosis was based on a positive cardiac biopsy or positive bone scintigraphy without monoclonal gammopathy. Echocardiographic measurements were categorized according to LV ejection fraction (LVEF) into HFpEF (LVEF ≥50%), HF with mildly reduced EF (HFmrEF, LVEF 40–49%), and HF with reduced EF (HFrEF, LVEF <40%). LV cavity size was categorized by LV end-diastolic diameter (LVEDD) and volume index (LVEDVi) as normal, moderately increased and severe dilatation. Results The study included 135 patients with ATTR-CM (mean age, 78 years; 89% male; 89% wild-type ATTR-CM). Most patients were screened for ATTR-CM because of unexplained HF and increased LV wall thickness (57%). Echocardiography showed LVEF <50% in 60% of the patients, with a significant portion presenting with HFrEF. Patients with LVEF <50% had higher NYHA class and elevated N-terminal pro-B-type natriuretic peptide levels than HFpEF patients. LV dilatation was observed in 43% of the patients, with 10% presenting with both LVEF <50% and severe LV dilatation. Conclusion This study revealed significant variability in HF phenotypes among patients with ATTR-CM, from HFpEF without LV dilatation to HFrEF with severe LV dilatation. Relying solely on HFpEF for screening may lead to under-diagnosis. These findings suggest the need for more comprehensive diagnostic criteria beyond echocardiographic measures to improve ATTR-CM detection and management.

An Increase in The Cross-Section of Two-Photon Absorption of Styrene Dye in Supramolecular Complexes with Cucurbituriles

Two-photon absorption cross sections of aqueous solutions of the styryl dye trans-4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide (DASPI) and its inclusion complexes with cucurbit[n]urils (CB[n] n = 6–8) were measured using fluorescence spectroscopy. A nonmonotonic dependence of the cross-section size on the excitation wavelength and on the cavitand cavity size was found. Compared with a free dye, a sevenfold increase in the two-photon absorption cross section was observed in DASPI inclusion complexes with CB[8] at an excitation wavelength of 980 nm.

Sensitivity analysis of an inverted T-shaped vertical tunneling field effect transistor biosensor based on inserted finger type

This paper presents a biosensor based on a finger-inserted inverted T-shaped vertical tunneling field effect transistor (FP-T-TFET). In order to improve the sensitivity and performance of the biosensor, a finger-inserted contact between the source and the channel is used. A comparative analysis between the biosensor based on FP-T-TFET and conventional inverted T-shaped TFET (T-TFET) is simulated for the electrical properties and sensitivity of neutral biomolecules with different dielectric constants and charged biomolecules with different charge densities. The noise analysis of the proposed structure is also performed. Then, the effects of insertion finger distribution, cavity size and filling volume on the performance of FP-T-TFET are investigated. Finally, the structure was subjected to linear analysis, in which the pearson coefficient was 0.92, indicating that the structure has good linear correlation. The results show that the FP-T-TFET biosensor has higher sensitivity in detecting various neutral and charged biomolecules. All device simulations were performed in the TCAD environment with a well-calibrated structure.

Unlocking of Hidden Mesopores for Enzyme Encapsulation by Dynamic Linkers in Stable Metal-Organic Frameworks.

Mesoporous metal-organic frameworks (MOFs) are promising supports for the immobilization of enzymes, yet their applications are often limited by small pore apertures that constrain the size of encapsulated enzymes to below 5 nm. In this study, we introduced labile linkers (4,4',4''-(2,4,6-boroxintriyl)-tribenzoate, TBTB) with dynamic boroxine bonds into mesoporous PCN-333, resulting in PCN-333-TBTB with enhanced enzyme loading and protection capabilities. The selective breaking of B-O bonds creates defects in PCN-333, which effectively expands both window and cavity sizes, thereby unlocking hidden mesopores for enzyme encapsulation. Consequently, this strategy not only increases the adsorption kinetics of small enzymes (<5 nm) such as cytochrome c (Cyt C) and horseradish peroxidase (HRP), but also enables the immobilization of various large-sized enzymes (>5 nm), such as glycoenzymes. The glycoenzymes@PCN-333-TBTB platform was successfully applied to synthesize thirteen complex oligosaccharides and polysaccharides, demonstrating high activity and enhanced enzyme stability. The dynamic linker-mediated enzyme encapsulation strategy enables the immobilization of enzymes exceeding the inherent pore size of MOFs, thus broadening the scope of enzymatic catalytic reactions achievable with MOF materials.