Permanent Cavities Research Articles

Supramolecular Interfacial Assembly: Integrating Supramolecular Hosts into Polymeric Membranes through an Aqueous Interface

AbstractEfficient incorporation of macrocycles in polymeric membranes can impart the overall matrix with new properties for a range of cutting‐edge applications. Here, we introduce a Supramolecular Interfacial Assembly (SIA) method for the fabrication of polymeric membranes featuring embedded macrocycles. Through harnessing the quasi‐liquid nature of the concentrated polymer solution, SIA orchestrates the homogeneous spreading of macrocycles in an aqueous layer on its surface, leading to the creation of an interface between “water/water” phases, subsequently forming a cross‐linked membrane driven by supramolecular electrostatic interactions. Remarkably, compared to the traditional interfacial polymerization, SIA adheres to a “green” paradigm without the need for organic solvents. The resultant composite membrane exhibits superior performance in organic solvent nanofiltration (OSN), owing to the precise molecular sieving property provided by the macrocycles with well‐defined permanent cavities. This fabrication method holds great promise for the innovative design and production of composite membranes that seamlessly integrates macrocycles with conventional polymers, which can greatly impact the design and preparation of advanced membrane materials in the future.

Supramolecular Interfacial Assembly: Integrating Supramolecular Hosts into Polymeric Membranes through an Aqueous Interface.

Efficient incorporation of macrocycles in polymeric membranes can impart the overall matrix with new properties for a range of cutting-edge applications. Here, we introduce a Supramolecular Interfacial Assembly (SIA) method for the fabrication of polymeric membranes featuring embedded macrocycles. Through harnessing the quasi-liquid nature of the concentrated polymer solution, SIA orchestrates the homogeneous spreading of macrocycles in an aqueous layer on its surface, leading to the creation of an interface between "water/water" phases, subsequently forming a cross-linked membrane driven by supramolecular electrostatic interactions. Remarkably, compared to the traditional interfacial polymerization, SIA adheres to a "green" paradigm without the need for organic solvents. The resultant composite membrane exhibits superior performance in organic solvent nanofiltration (OSN), owing to the precise molecular sieving property provided by the macrocycles with well-defined permanent cavities. This fabrication method holds great promise for the innovative design and production of composite membranes that seamlessly integrates macrocycles with conventional polymers, which can greatly impact the design and preparation of advanced membrane materials in the future.

Experimental Tests on External and Terminal Ballistics of Different Types of Projectiles Fired From .38 SPL Caliber Cartridges and Study of Permanent Cavitation in Anatomical Modeling With 10% Ballistic Gelatin.

The present study investigated the main morphological differences between the permanent cavities formed by 4 different types of projectiles fired from .38 SPL caliber cartridges in blocks of 10% ballistic gelatin with standardized formulation (Federal Bureau of Investigation Protocol), all fired from the same distance and from the same firearm, associated with its performances in external and terminal ballistics. The velocity or the mass presented by a firearm projectile will not always be solely responsible for the final configuration of the permanent cavity, in which the projectile design, for example, is an equally important element. Each type of projectile tested in the present work generated a different kind of permanent cavity, but they also varied in velocity (m/s) and energy (J). The use of 10% ballistic gelatin in scientific research that seeks to investigate the external and terminal ballistics of projectiles can contribute to the practice of professionals working either in forensic pathology or applied ballistics scenarios, as they can experimentally simulate the events that can occur in the tissues of victims inflicted by gunshot wounds, which also allows important applications in the medical, commercial, civil, and military sectors that deal with products and technologies related to the human body.

CHARACTERISTICS OF SOFT TISSUE WOUNDS CAUSED BY BULLETS FROM INFANTRY GUNS ON EXPERIMENTAL ANIMALS

Objectives: To describe some characteristics of soft tissue wounds caused by bullets from infantry guns on experimental animals. Methods: A descriptive study on the characteristics of macroscopic lesions of soft tissue wounds caused by bullets from infantry guns on experimental animals. Shooting on each pig corresponds to a type of ammunition, including 5.56 x 45mm bullet, 7.62 x 39mm bullet, and 9 x 19mm bullets to create wounds in the chest area, liver area, abdomen, and buttock area, then those lesions were examined. Results: All wounds had entry wounds with a size smaller than the size of the corresponding bullet. Most entry wounds were round (range of 65% - 75%), while others were oval in shape. Bullets 9 x 19mm caused the most graze wounds (45%). Bullets with high damage energy and velocity caused larger outlet damage and were larger than the corresponding bullet size. The exit wounds caused by 7.62 x 39mm bullets and 5.56 x 45mm bullets were mainly in oval shape (80% and 85%, respectively); the rest were star-shaped. Exit wounds from the 9 x 19mm bullet were mostly oval in shape (92.5%). The shape of the 7.62 x 39mm and 5.56 x 45mm bullet-related permanent cavities had an angular, jagged form, the 9 x 19mm bullet permanent cavities were mostly straight, with little angle. Conclusion: All entry wounds had a smaller size than that of the corresponding bullet, most of which were round. The bullets with high velocity and energy damage caused larger damage and larger than the corresponding bullet size, mostly oval in shape, the rest were star-shaped. The shape of the 7.62 x 39mm and 5.56 x 45mm bullet permanent cavities had an angular, jagged form, the 9 x 19mm bullet permanent cavity was mostly straight, with little angle.

Transformation of Type III to Type II Porous Liquids by Tuning Surface Rigidity of Rhodium(II)‐Based Metal‐Organic Polyhedra for CO2 Cycloaddition

AbstractPorous liquids (PLs), a summation of porous hosts and bulky solvents bestowing permanent cavities, are the prominent emerging materials. Despite great efforts, exploration of porous hosts and bulky solvents is still needed to develop new PL systems. Metal‐organic polyhedra (MOPs) with discrete molecular architectures can be considered as porous hosts; however, many of them are insoluble entities. Here we report the transformation of type III PL to type II PLs by tuning the surface rigidity of insoluble MOP, Rh24L24, in a bulky ionic liquid (IL). Functionalization of N‐donor molecules on Rh−Rh axial sites ensue their solubilization in bulky IL which confer type II PLs. Experimental and theoretical studies reveal the bulkiness of IL as per the cage apertures, and the cause of their dissolution as well. The obtained PLs, capturing more CO2 than neat solvent, have depicted higher catalytic activity for CO2 cycloaddition compared to individual MOPs and IL.

Transformation of Type III to Type II Porous Liquids by Tuning Surface Rigidity of Rhodium(II)-Based Metal-Organic Polyhedra for CO2 Cycloaddition.

Porous liquids (PLs), a summation of porous hosts and bulky solvents bestowing permanent cavities, are the prominent emerging materials. Despite great efforts, exploration of porous hosts and bulky solvents is still needed to develop new PL systems. Metal-organic polyhedra (MOPs) with discrete molecular architectures can be considered as porous hosts; however, many of them are insoluble entities. Here we report the transformation of type III PL to type II PLs by tuning the surface rigidity of insoluble MOP, Rh24L24, in a bulky ionic liquid (IL). Functionalization of N-donor molecules on Rh-Rh axial sites ensue their solubilization in bulky IL which confer type II PLs. Experimental and theoretical studies reveal the bulkiness of IL as per the cage apertures, and the cause of their dissolution as well. The obtained PLs, capturing more CO2 than neat solvent, have depicted higher catalytic activity for CO2 cycloaddition compared to individual MOPs and IL.

Preparation of Chiral Porous Organic Cage Clicked Chiral Stationary Phase for HPLC Enantioseparation.

Porous organic cages (POCs) are a new subclass of porous materials, which are constructed from discrete cage molecules with permanent cavities via weak intermolecular forces. In this study, a novel chiral stationary phase (CSP) has been prepared by chemically binding a [4 + 6]-type chiral POC (C120H96N12O4) with thiol-functionalized silica gel using a thiol-ene click reaction and applied to HPLC separations. The column packed with this CSP presented good separation capability for chiral compounds and positional isomers. Thirteen racemates have been enantioseparated on this column, including alcohols, diols, ketones, amines, epoxides, and organic acids. Upon comparison with a previously reported chiral POC NC1-R-based column, commercial Chiralpak AD-H, and Chiralcel OD-H columns, this column is complementary to these three columns in terms of its enantiomeric separation; and can also separate some racemic compounds that cannot be separated by the three columns. In addition, eight positional isomers (iodoaniline, bromoaniline, chloroaniline, dibromobenzene, dichlorobenzene, toluidine, nitrobromobenzene, and nitroaniline) have also been separated. The influences of the injection weight and column temperature on separation have been explored. After the column has undergone multiple injections, the relative standard deviations (RSDs) for the retention time and selectivity were below 1.0 and 1.5%, respectively, indicating the good reproducibility and stability of the column for separation. This work demonstrates that POCs are promising materials for HPLC separation.

Ballistic Wound Evaluation Based on Dye Diffusion Method

Ballistic gelatin is widely used as a kind of tissue simulants in wound ballistics. Evaluations of the wound tract of gelatin by projectiles are mainly based on fissures in the gelatin slices. For there are difficulties in building relationships between the areas and the fissures, a new method based on dye diffusion is proposed in this paper. Colored regions in the slices are obtained after penetration of a Chinese 7.62mm rifle bullet into the gelatin block. The colored regions can be divided into ‘X’, ‘I’ and branching ‘I’ shapes. In the second half of the penetration, there is a strong correlation between the areas of the regions and the energy dissipation of the bullet. However, the correlation is poor in the first half of the penetration. Branches of the colored regions mainly distributed at the heads and tails of the permanent cavities. The permanent cavities’ shapes have a great dependence on the nutation angles of the bullets. Orientation angles of the permanent cavities are determined by the precession angles of the bullets.

Transition Metal Nanoparticles‐Catalyzed Organic Reactions within Porous Organic Cages

AbstractTransition metal catalysis has played an important role in modern organic chemistry. In order to develop highly efficient and sustainable methodologies, considerable efforts have been devoted to combining the benefits of homogeneous catalysis and heterogeneous catalysis. Porous organic cages (POCs) are a relatively new type of discrete molecules with permanent cavities and good solubilities. These intrinsic properties make POCs expedient catalyst support for the homogenization of heterogeneous transition metal nanoparticles (MNPs). This review mainly focuses on the recent progress of MNPs‐catalyzed reductions and coupling reactions within POCs. In most cases, the MNPs@POC complexes have exhibited outstanding reactivity, dispersibility, stability, and reusability. These pioneering contributions have enriched the methodology toolbox for advanced organic synthesis.

Permanent cavities in ionic liquids created by metal–organic polyhedra

A new porous liquid system based on the coalition of MOPs and bulky IL was designed. The liquid materials exhibit permanent cavities, long-term durability, and good ability to separate CO2 from N2 and CH4 not only as an entity but also as a membrane.

The method of closing macular holes with partial preservation of the internal limiting membrane

To suggest a new technique and to evaluate the dynamics of anatomical and functional parameters after surgery for macular hole with preservation of ILM. The study examined the results of treatment of 52 patients (52 eyes) with end-to-end macular holes of stages 2 to 4 according to the Gass classification. Patients of the 1st group underwent standard surgical treatment: vitrectomy and then circular maculorhexis. Patients of group 2 were operated according to the original method with partial preservation of ILM in the foveolar zone. All patients underwent standard ophthalmological examination before and after the surgery. The morphometric data was evaluated using optical coherence tomography (OCT). Statistical processing of the results was carried out using IBM SPSS Statistics 23 software. Morphofunctional parameters of the retina did not differ between patients of the two groups before treatment. According to the results of surgical treatment, on day 7 after the operation, higher indices of functional parameters of the retina were observed in patients of the 2nd group. On day 30, patients of group 2 were observed to have an increase in best-corrected visual acuity (BCVA) in comparison with these indicators on day 7, and a significant increase in comparison with the data before surgery. In patients of group 1, no improvement of vision was observed. It was also revealed that holes with permanent cystic cavities have the worst prognoses in terms of increasing visual functions and restoring the foveolar profile. The described procedure allows partial preservation of ILM, which reduces the risk of intraoperative damage to the retinal layers; the observed functional results were higher.

Assessing the Changes in the Moisture/Dryness of Water Cavity Surfaces in Imlili Sebkha in Southwestern Morocco by Using Machine Learning Classification in Google Earth Engine

Imlili Sebkha is a stable and flat depression in southern Morocco that is more than 10 km long and almost 3 km wide. This region is mainly sandy, but its northern part holds permanent water pockets that contain fauna and flora despite their hypersaline water. Google Earth Engine (GEE) has revolutionized land monitoring analysis by allowing the use of satellite imagery and other datasets via cloud computing technology and server-side JavaScript programming. This work highlights the potential application of GEE in processing large amounts of satellite Earth Observation (EO) Big Data for the free, long-term, and wide spatio-temporal wet/dry permanent salt water cavities and moisture monitoring of Imlili Sebkha. Optical and radar images were used to understand the functions of Imlili Sebkha in discovering underground hydrological networks. The main objective of this work was to investigate and evaluate the complementarity of optical Landsat, Sentinel-2 data, and Sentinel-1 radar data in such a desert environment. Results show that radar images are not only well suited in studying desertic areas but also in mapping the water cavities in desert wetland zones. The sensitivity of these images to the variations in the slope of the topographic surface facilitated the geological and geomorphological analyses of desert zones and helped reveal the hydrological functions of Imlili Sebkha in discovering buried underground networks.

Recent advances of application of porous molecular cages for enantioselective recognition and separation.

Porous materials with well-defined pore structures have received considerable attention in the past decades due to their unique structures and wide applications. Most porous materials such as zeolites, metal-organic frameworks, covalent organic frameworks, and porous organic polymers are extended to infinite frameworks or networks by robust covalent or coordination bonds. Porous molecular cages composed of discrete molecules with permanent cavities are an emerging class of porous material and the discrete molecules assemble into solids by weak intermolecular interaction. In comparison to porous extended solids such as metal-organic frameworks and covalent organic frameworks, porous molecular cage solids are generally soluble in organic solvents thus allowing solution processing, making them more convenient to apply in many fields. This review mainly focuses on the recent advances of application of porous molecular cages (porous organic cages and metal-organic cages) for enantioselective recognition and separation from 2010 to present, including gas chromatography, capillary electrochromatography, chiral fluorescent recognition, chiral potentiometric sensing, and enantioselective adsorption. Furthermore, the two important family members of porous molecular cages, porous organic cages and metal-organic cages, are also discussed.

µ-metal magnetic cavities for polarization and maintenance of polarization of 3He gas

Low gradient magnetic holding fields are required for maintaining the polarization of polarized 3He, as diffusion though non-ideal gradients can cause total relaxation rates much greater than the intrinsic total 3He relaxation rate of a particular 3He cell in optimal conditions. For neutron scattering applications we often rely on µ-metal cavities to provide a degree of shielding from the many other sources of magnetic fields and gradient experienced on a typical neutron instrument. The JCNS utilizes two concepts for such cavities, one based on inexpensive plastic-bonded magnets to provide magnetic flux, and the other based on field coils wound on the sides of the µ-metal cavity. 2 different sized of permanent magnet cavities and three different geometries of coil-based cavities have been produced. Both types of boxes will be presented with magnetic design as well as mechanical construction details along with the achieved performance of the constructed devices.

Enantioseparations by Gas Chromatography Using Porous Organic Cages as Stationary Phase.

The resolution of chiral compounds into optically pure enantiomers is very important in various fields, such as pharmaceutical, chemical, agricultural, and food industries. Chiral gas chromatography (GC) is one of the efficient methods for enantioseparations of volatile compounds. In recent years, porous materials as stationary phases for chromatographic separations have achieved increasing attention. Porous organic cages (POCs) represent an emerging class of porous materials, which are assembled by discrete organic molecules with shape-persistent and permanent cavities through weak intermolecular forces. This chapter describes several chiral POCs as chiral stationary phases for GC enantioseparations of racemic compounds.

A metal-nano GO frameworks/PPS membrane with super water flux and high dyes interception

Nano graphene oxide (NGO) particles with the multiscale structure were prepared, and divalent metal cations (Ca2+, Cu2+ and Mg2+) were employed as crosslinking agents to closely stack nano NGO particles both on the surface and in the pore-channels of poly(p-phenylene sulfide) (PPS) membrane support forming the novel filter layer which had the similar structure with metal-organic frameworks (MOFs) through electrostatic forces and coordination bonds. Metal-NGO framework exhibited the similar MOFs structure with permanent nanoscale cavities and open channels, and Metal-NGO frameworks modified PPS membrane displayed the most excellent H2O permeability and high dyes rejection performance. In Metal-NGO/PPS hybrid membrane, Metal-NGO frameworks were closely attached with PPS membrane surface though the coordination between metal ions and -S- of PPS. Compared with the transversal interlayer molecular transport channel of conventional GO membranes, Metal-NGO frameworks modified PPS membrane possessed the shortest permeable channel, highest pore-opening rate, continuous GO transmission layer and multistage structure of nano channel, endowing the membrane with ultrafast water molecular transport rate and high pure-water flux of 3109.5 LMH/MPa. Furthermore, the prepared Metal-NGO frameworks modified PPS membrane exhibited the high rejection rate at 99.9% in RB rejection.

Magnetorheological finishing of ferromagnetic blind-hole type surfaces

ABSTRACTProducts having blind-hole type surfaces such as bottle caps are being manufactured in today’s industry and are of great use. Such products are made in permanent blind-hole type mold cavities. At present, these cavities are being finished by internal grinding operations. After grinding, surface defects such as deep-seated groove, cavity, axial scratch, and ploughed material are induced because of uncontrollable finishing forces applied by grinding pins onto the workpiece surface. To obtain a better quality on final-made products, the blind-hole type mold cavities should be made defect-free. In the present process, two different tools based on magnetorheological fluid are developed to finish the lateral and bottom surfaces of cylindrical blind-hole type mold cavities. The workpiece used for finishing is the hardened EN31 die steel. The finite element studies determined the variation in magnetic field within the working gaps. The change in surface roughness (Ra) values of both inner lateral and bottom surfaces reduced by 67.7% and 69.5%, respectively, and found significant improvement in surface characteristics as compared to the initial grind surfaces. The results revealed the usefulness of present process to finish the blind-hole type mold cavities in manufacturing industries for producing a better quality of final-made products.

An experimental study on the effects of the head angle and bullet diameter on the penetration of a gelatin block

This research conducts 300 small-scale ammunition experiments using moderate bullet speeds and a variety of bullet configurations in order to understand the relationship between penetration behavior and bullet shape. To maximize the survivability of soldiers and reduce their vulnerability and ballistics wounds, it is very important to understand the penetration physics of bullets. Inside human bodies, tumbling and traveling trajectories are important factors to consider when analyzing human injuries due to ballistics. Therefore, many kinds of bullets and armor have been proposed to minimize or maximize human damage. In this study, to support the development of bullets, 10 bullets with different head angle shapes and different diameters were manufactured and fired at speeds less than 200m/s towards transparent gelatin blocks, and the damage mechanisms, i.e., temporary cavities and permanent cavities, were studied by taking penetration images using a high speed camera. It was found that the tumbling and rotations of bullets are influenced by kinetic energies and the shapes of bullets, and several empirical relationships are derived. The results suggest that the shapes and the diameters are crucial factors for ballistics wounds.

Ballistics and anatomical modelling - A review.

Ballistics is the study of a projectiles motion and can be broken down into four stages: internal, intermediate, external and terminal ballistics. The study of the effects a projectile has on a living tissue is referred to as wound ballistics and falls within terminal ballistics. To understand the effects a projectile has on living tissues the mechanisms of wounding need to be understood. These include the permanent and temporary cavities, energy, yawing, tumbling and fragmenting. Much ballistics research has been conducted including using cadavers, animal models and simulants such as ballistics ordnance gelatine. Further research is being conducted into developing anatomical, 3D, experimental and computational models. However, these models need to accurately represent the human body and its heterogeneous nature which involves understanding the biomechanical properties of the different tissues and organs. Further research is needed to accurately represent the human tissues with simulants and is slowly being conducted.

A chiral porous organic cage for molecular recognition using gas chromatography

Molecular organic cages as shape-persistent organic molecules with permanent and accessible cavities have attracted a lot of interest because of their importance as host-guest systems. Herein, we report a chiral porous organic cage (POC) CC9 diluted with a polysiloxane OV-1701 to fabricate a CC9-coated capillary column, which was used for the high-resolution gas chromatographic separation of organic compounds, including positional isomers and racemates. On the CC9-coated capillary column, a large number of racemic compounds such as chiral alcohols, esters, ethers and epoxides can be resolved without derivatization. By comparing the chiral recognition ability of the CC9-coated column with the commercially available β-DEX 120 column and the POC CC3-R coated column recently reported by our group, the CC9-coated column offered good resolution during the separation of some racemates, that were not separated using the β-DEX 120 column or POC CC3-R coated column. Therefore, the CC9-coated column can be complementary to the β-DEX 120 column and CC3-R coated column. The results indicated that the CC9-coated column exhibited great potential for application in the separation of positional isomers and enantiomers with great selectivity, high resolution and good reproducibility.