Study on Explosion Characteristics and Mechanism of Electrostatic Spray Powder.

In order to fully understand the explosion risk of electrostatic spraying powder, corresponding preventive measures are put forward. The explosion characteristics, ignition sensitivity, and flame propagation of three typical electrostatic spraying powders were tested using a 20 L spherical explosion test device, a G-G furnace test device, and a Hartmann tube test device, and the explosion process and mechanism of electrostatic spraying powders were discussed. The results show that the maximum explosion pressure and the maximum explosion pressure rise rate increase first and then decrease with the increase in mass concentration. The maximum explosion pressure and the maximum explosion pressure rise rate of acrylic powder coating are the largest, which are 0.75 and 85.4 MPa/s, respectively. The shortest burning time is 97.5 ms, and the highest explosion danger level is 23.46 MPa·m/s. The flame propagation of electrostatic spraying powder develops slowly; the flame front spreads linearly and the average flame velocity increases first and then decreases. The explosive development process of powder coating particles is concentrated in the three-phase system of solid particles, molten particles, and pyrolytic gasification combustible gas, which goes through the kinetic process of particle heating melting, cross-linking curing, pyrolytic gasification, combustion, and extinction.

Exploring the causal relationship between gut microbiota and frailty: a two-sample mendelian randomization analysis.

Background: Frailty is a complex geriatric syndrome that seriously affects the quality of life of older adults. Previous observational studies have reported a strong relationship of frailty with the gut microbiota; however, further studies are warranted to establish a causal link. Accordingly, we aimed to conduct a bidirectional Mendelian randomization study to assess the causal relationship between frailty, as measured by the frailty index, and gut microbiota composition. Methods: Instrumental variables for the frailty index (N = 175, 226) and 211 gut bacteria (N = 18,340) were obtained through a genome-wide association study. A two-sample Mendelian randomization analysis was performed to assess the causal relationship of gut microbiota with frailty. Additionally, we performed inverse Mendelian randomization analyses to examine the direction of causality. Inverse variance weighting was used as the primary method in this study, which was supplemented by horizontal pleiotropy and sensitivity analyses to increase confidence in the results. Results: Bacteroidia (b = -0.041, SE = 0.017, p = 0.014) and Eubacterium ruminantium (b = -0.027, SE = 0.012, p = 0.028) were protective against frailty amelioration. Additionally, the following five bacteria types were associated with high frailty: Betaproteobacteria (b = 0.049, SE = 0.024, p = 0.042), Bifidobacterium (b = 0.042, SE = 0.016, p = 0.013), Clostridium innocuum (b = 0.023, SE = 0.011, p = 0.036), E. coprostanoligenes (b = 0.054, SE = 0.018, p = 0.003), and Allisonella (b = 0.032, SE = 0.013, p = 0.012). Contrastingly, frailty affected Butyrivibrio in the gut microbiota (b = 1.225, SE = 0.570, p = 0.031). The results remained stable within sensitivity and validation analyses. Conclusion: Our findings strengthen the evidence of a bidirectional causal link between the gut microbiota and frailty. It is important to elucidate this relationship to optimally enhance the care of older adults and improve their quality of life.

Tunable templating of photonic microparticles via liquid crystal order-guided adsorption of amphiphilic polymers in emulsions.

Multiple emulsions are usually stabilized by amphiphilic molecules that combine the chemical characteristics of the different phases in contact. When one phase is a liquid crystal (LC), the choice of stabilizer also determines its configuration, but conventional wisdom assumes that the orientational order of the LC has no impact on the stabilizer. Here we show that, for the case of amphiphilic polymer stabilizers, this impact can be considerable. The mode of interaction between stabilizer and LC changes if the latter is heated close to its isotropic state, initiating a feedback loop that reverberates on the LC in form of a complete structural rearrangement. We utilize this phenomenon to dynamically tune the configuration of cholesteric LC shells from one with radial helix and spherically symmetric Bragg diffraction to a focal conic domain configuration with highly complex optics. Moreover, we template photonic microparticles from the LC shells by photopolymerizing them into solids, retaining any selected LC-derived structure. Our study places LC emulsions in a new light, calling for a reevaluation of the behavior of stabilizer molecules in contact with long-range ordered phases, while also enabling highly interesting photonic elements with application opportunities across vast fields.

Research on the Inhibition Effect of NaCl on the Explosion of Mg-Al Alloy Powder.

A study was conducted on the explosion overpressure and flame propagation law of magnesium-aluminum (Mg-Al) alloy powder, and the suppression mechanism of sodium chloride (NaCl) on the explosion of magnesium-aluminum alloy powder was explored. Adding NaCl powder can effectively reduce the explosion pressure, flame front position, and flame propagation speed. The higher the amount of NaCl powder added, the lower the explosion pressure of magnesium-aluminum alloy powder, the slower the flame propagation speed, and the lower the flame brightness. NaCl adsorbed on Mg-Al alloy powder isolated heat transfer and played a cooling role. The Cl- produced by NaCl decomposition will react with the free radicals H+ and OH- in the reaction system, which will reduce the concentration of H+ and OH- in the combustion process and hinder the propagation and expansion of the flame. The research results provide theoretical guidance for the explosion prevention of Mg-Al alloy powder and the preparation of a physical-chemical compound explosion suppressor in the later stage.

TGFß2 mediates oxidative stress-induced epithelial-to-mesenchymal transition of bladder smooth muscle.

Bladder outlet obstruction (BOO) is the primary clinical manifestation of benign prostatic hyperplasia, the most common urinary system disease in elderly men, and leads to associated lower urinary tract symptoms. Although BOO is reportedly associated with increased systemic oxidative stress (OS), the underlying mechanism remains unclear. The elucidation of this mechanism is the primary aim of this study. A Sprague-Dawley rat model of BOO was constructed and used for urodynamic monitoring. The bladder tissue of rats was collected and subjected to real-time reverse transcription-quantitative polymerase chain reaction (RT-qPCR), histological examination, and immunohistochemical staining. Through bioinformatics prediction, we found that transforming growth factor ß2 (TGFß2) expression was upregulated in rats with BOO compared with normal bladder tissue. In vitro analyses using primary bladder smooth muscle cells (BSMCs) revealed that hydrogen peroxide (H2O2) induced TGFß2 expression. Moreover, H2O2 induced epithelial-to-mesenchymal transition (EMT) by reducing E-cadherin, an endothelial marker and CK-18, a cytokeratin maker, and increasing mesenchymal markers, including N-cadherin, vimentin, and α-smooth muscle actin (α-SMA) levels. The downregulation of TGFß2 expression in BSMCs using siRNA technology alleviated H2O2-induced changes in EMT marker expression. The findings of the study indicate that TGFß2 plays a crucial role in BOO by participating in OS-induced EMT in BSMCs.

Engineering Entropy-Driven Nanomachine-Mediated Morphological Evolution of Anisotropic Silver Triangular Nanoplates for Colorimetric and Photothermal Biosensing.

A DNA/RNA biosensor capable of single nucleotide variation (SNV) resolution is highly desirable for drug design and disease diagnosis. To meet the point-of-care demand, rapid, cost-effective, and accurate SNV detection is of great significance but still suffers from a challenge. In this work, a unique nonenzymatic dual-modal (multicolorimetric and photothermal) visualization DNA biosensor is first proposed for SNV identification on the basis of an entropy-driven nanomachine with double output DNAs and coordination etching of anisotropic silver triangular nanoplates (Ag TNPs). When the target initiates the DNA nanomachine, the liberated multiple output DNAs can be utilized as a bridge to produce a superparamagnetic sandwich complex. The incoming poly-C DNA can coordinate and etch highly active Ag+ ions at the tips of Ag TNPs, causing a shift in the plasmon peak of Ag TNPs from 808 to 613 nm. The more target DNAs are introduced, the more output DNAs are released and thus the more Ag+ ions are etched. The noticeable color changes of anisotropic Ag TNPs can be differentiated by "naked eye" and accurate temperature reading. The programmable DNA nanotechnology and magnetic extraction grant the high specificity. Also, the SNV detection results can be self-verified by the two-signal readouts. Moreover, the dual-modal biosensor has the advantages of portability, cost-effectiveness, and simplicity. Particularly, the exclusive entropy-driven amplifier liberates double output DNAs to bridge more poly-C DNAs, enabling the dual-modal visualization DNA biosensor with improved sensitivity.

Exploring the micromorphological characteristics of adult lower cervical vertebrae based on micro-computed tomography.

We will use micro-computed tomography to scan 31 sets of the adult lower cervical vertebrae (155 vertebrae) to observe the morphological characteristics and direction of trabeculae in the lower cervical vertebrae by outlining and reconstructing the regions of interest and to calculate the variation laws of the microstructure in the regions of interest to reveal their structural characteristics and weak areas. As a result, the images showed that the trabeculae in the lower cervical pedicle near the medial and lateral cortices were relatively dense, and their bone plates were lamellar. There were cavities between the superior and inferior articular processes where the ossification centers had not been absorbed after ossified. The lamellar trabeculae in the vertebral plates near the cortical bones were only 1-2 layers, extended and transformed into rod-shaped trabeculae in a radial shape toward the medullary space. The lamellar trabeculae of the vertebral plate extend over the spinous process near the cortical bone. The statistical results of the trabeculae's morphological parameters showed significant differences in bone volume fraction values among the four parts (P < 0.05). There were substantial differences in BS/BV, except for no differences between the pedicle and the vertebral plate (P < 0.05). There was a significant difference in trabecular pattern factor values between the articular process, the spinous process, and the vertebral plate (P < 0.05) and a significant difference between the pedicle, the spinous process, and the vertebral plate (P < 0.05). There were no significant differences in trabecular bone thickness and trabecular space values among the four parts (P < 0.05). The anatomical microstructural perspective confirms that the optimal choice is internal fixation via the pedicle. If using pedicle screws, the nail tract needs to be placed into the spinous process to increase its holding power and resistance to extraction.

miR-199a-5p from bone marrow mesenchymal stem cell exosomes promotes the proliferation of neural stem cells by targeting GSK-3ß.

Bone marrow mesenchymal stem cell (BMSC)-derived exosomes are a promising therapeutic agent for human disease, but their effects on neural stem cells (NSCs) subject to spinal cord ischaemia-reperfusion injury (SCIRI) remain unknown. Here, we examine the impact of miR-199a-5p-enriched exosomes derived from BMSCs on NSC proliferation. We establish a rat model of aortic cross-clamping to induce SCIRI in vivo and a primary NSC model of oxygen-glucose deprivation/reoxygenation (OGD/R) to simulate SCIRI in vitro. CCK8, EdU, and BrdU assays are performed to evaluate the proliferation of NSCs. Hematoxylin and eosin (H&E) staining is used to determine the number of surviving neurons. The Basso, Beattie, and Bresnahan (BBB) scale and inclined plane test (IPT) are used to evaluate hind limb motor function. DiO-labelled exosomes are efficiently internalized by NSCs and increase ectopic amounts of miR-199a-5p, which promotes the proliferation of NSCs. In contrast, exosomes derived from miR-199a-5p-depleted BMSCs exert fewer beneficial effects. MiR-199a-5p targets and negatively regulates glycogen synthase kinase 3ß (GSK-3ß) and increases nuclear ß-catenin and cyclin D1 levels. miR-199a-5p inhibition reduces the total number of EdU-positive NSCs after OGD/R, but the GSK-3ß inhibitor CHIR-99021 reverses this effect. In vivo, intrathecal injection of BMSC-derived exosomes increases the proliferation of endogenous spinal cord NSCs after SCIRI. In addition, more proliferating NSCs are found in rats intrathecally injected with exosomes overexpressing miR-199a-5p. In summary, miR-199a-5p in BMSC-derived exosomes promotes NSC proliferation via GSK-3ß/ß-catenin signaling.

Highly conductive and tough polyacrylamide/sodium alginate hydrogel with uniformly distributed polypyrrole nanospheres for wearable strain sensors.

Conductive hydrogels have attracted widespread attention because of their integrated characteristics of being stretchable, deformable, adhesive, self-healable, and conductive. Herein, we report a highly conductive and tough double-network hydrogel based on a double cross-linked polyacrylamide (PAAM) and sodium alginate (SA) network with conducting polypyrrole nanospheres (PPy NSs) uniformly distributed in the network (PAAM-SA-PPy NSs). SA was employed as a soft template for synthesis of PPy NSs and distribution of PPy NSs uniformly in the hydrogel matrix to construct SA-PPy conductive network. The PAAM-SA-PPy NS hydrogel exhibited both high electrical conductivity (6.44 S/m) and excellent mechanical properties (tensile strength of 560 kPa at 870 %), as along as high toughness, high biocompatibility, good self-healing and adhesion properties. The assembled strain sensors showed high sensitivity and a wide sensing range (a gauge factor of 1.89 for 0-400 % strain and 4.53 for 400-800 % strain, respectively), as well as fast responsiveness and reliable stability. When used as a wearable strain sensor, it was able to monitor a series of physical signals from human large-scale joint motions and subtle muscle movements. This work provides a new strategy for the development of electronic skins and flexible strain sensors.

Branched polyethylenimine-assisted boronic acid functionalized magnetic nanoparticles for highly efficient capture of lincomycin and clindamycin.

As lincosamide antibiotics, lincomycin and clindamycin are widely used in the drug manufacturing industry for the health of human beings and animals. Thus, the quantitative detection of them in real samples is of great significance. Due to the presence of complex interfering components in actual samples, the separation and enrichment of lincomycin and clindamycin prior to analysis are key. Therefore, it is necessary to develop a non-complex, cost-effective enrichment method for them. A five- or six-membered boronic cyclic ester is formed through boronate affinity materials binding a cis-diol-containing compound in aqueous media, which is a reversible reaction. However, low binding capacity and affinity, and high binding pH of boronate affinity materials are key concerns. In this study, polyethylenimine-assisted 3-fluoro-4-formylphenylboronic acid functionalized magnetic nanoparticles were developed to capture efficiently cis-diol-containing lincomycin and clindamycin under neutral conditions. Thereinto, polyethylenimine (PEI) was applied as a scaffold to amplify the number of boronic acid moieties. And 3-fluoro-4-formylphenylboronic acid was used as an affinity ligand due to its excellent water solubility and low pKa value toward lincomycin and clindamycin. The results indicated that the prepared branched boronic acid-functionalized MNPs provided high binding capacity and fast binding kinetics under neutral conditions. Furthermore, the obtained MNPs exhibited relatively high binding affinity (Kd ≈ 10-4 M) and low binding pH (pH ≥ 6.0).

The Extended Pterional Approach Allows Satisfactory Results for the Resection of Huge Medial Sphenoid Ridge Meningioma.

OBJECTIVE: To investigate the surgical method and efficacy of the extended pterional approach in the resection of huge medial sphenoid ridge meningiomas (MSRMs). METHODS: Retrospective analysis of clinical data from 41 patients diagnosed with MSRMs (diameter ≥4.0 cm) from Nanjing Brain Hospital between January 2012 and February 2022 was conducted. Within 24 hours after surgery, head computed tomography and magnetic resonance imagingwere reviewed to evaluate the extent of tumor resection based on Simpson grading. Cranial magnetic resonance imagingwas repeated 3 to 60 months after surgery to assess tumor recurrence or progression. Preoperative, discharge, and follow-up Karnofsky functional status scores (KPS) were assessed to determine patients' functional status. Repeated-measures analysis of variance was utilized to compare KPS at preoperative, hospital discharge, and final follow-up. RESULTS: The 41 selected cases included 38 cases (92.7%) of Simpson I-III resection and 3 cases (7.3%) of Simpson IV resection. All the cases had typical pathological features and definite pathological diagnoses. There were 2 recurrent tumors and 4 progressed tumors when the patients were followed up from 3 months to 60 months after operations. The results demonstrated that the KPS score at the final follow-up (91.4 ± 9.6) was higher than at hospital discharge (85.3 ± 8.9) and preoperation (78.2 ± 8.5) (F = 69.46, P = 0.033). CONCLUSIONS: The use of the extended pterional approach in the resection of huge MSRMs appears to be an effective surgical method. Careful dissection and preservation of vascular and neural structures, as well as meticulous microsurgical techniques in managing cavernous sinus tumors, can lead to reduced surgical complications and improved treatment outcomes.

Identification of Ubr1 as an amino acid sensor of steatosis in liver and muscle.

BACKGROUND: Malnutrition is implicated in human metabolic disorders, including hepatic steatosis and myosteatosis. The corresponding nutrient signals and sensors as well as signalling pathways have not yet been well studied. This study aimed to unravel the nutrient-sensing mechanisms in the pathogenesis of steatosis. METHODS: Plin2, a lipid droplet (LD) protein-inhibiting lipolysis, is associated with steatosis in liver and muscle. Taking advantage of the Gal4-UAS system, we used the Drosophila melanogaster wing imaginal disc as an in vivo model to study the regulation of Plin2 proteostasis and LD homeostasis. Drosophila Schneider 2 (S2) cells were used for western blotting, immunoprecipitation assays, amino acid-binding assays and ubiquitination assays to further investigate the regulatory mechanisms of Plin2 in response to nutrient signals. Mouse AML12 hepatocytes, human JHH-7 and SNU-475 hepatoma cells were used for immunofluorescence, western blotting and immunoprecipitation to demonstrate that the mode of Plin2 regulation is evolutionarily conserved. In addition, we purified proteins from HEK293 cells and reconstituted in vitro cell-free systems in amino acid-binding assays, pulldown assays and ubiquitination assays to directly demonstrate the molecular mechanism by which Ubr1 senses amino acids to regulate Plin2 proteostasis. RESULTS: As a lipolysis inhibitor, Plin2 was significantly elevated in liver (P < 0.05) and muscle (P < 0.05) in patients with steatosis. Consistently, we found that the ubiquitin moiety can be conjugated to any Lys residue in Plin2, ensuring robust clearance of Plin2 by protein degradation. We further demonstrated that the E3 ubiquitin ligase Ubr1 targets Plin2 for degradation in an amino acid-dependent manner. Ubr1 uses two canonical substrate-binding pockets, independent of each other, to bind basic and bulky hydrophobic amino acids, respectively. Mechanistically, amino acid binding allosterically activates Ubr1 by alleviating Ubr1's auto-inhibition. In the absence of amino acids, or when the amino acid-binding capacity of Ubr1 is diminished, Ubr1-mediated Plin2 degradation is inactivated, leading to steatosis. CONCLUSIONS: We identified Ubr1 as an amino acid sensor regulating Plin2 proteostasis, bridging the knowledge gap between steatosis and nutrient sensing. Our work may provide new strategies for the prevention and treatment of steatosis.

Development and Experimental Validation of a Novel Prognostic Signature for Gastric Cancer.

BACKGROUND: Gastric cancer is a malignant tumor with high morbidity and mortality. Therefore, the accurate recognition of prognostic molecular markers is the key to improving treatment efficacy and prognosis. METHODS: In this study, we developed a stable and robust signature through a series of processes using machine-learning approaches. This PRGS was further experimentally validated in clinical samples and a gastric cancer cell line. RESULTS: The PRGS is an independent risk factor for overall survival that performs reliably and has a robust utility. Notably, PRGS proteins promote cancer cell proliferation by regulating the cell cycle. Besides, the high-risk group displayed a lower tumor purity, higher immune cell infiltration, and lower oncogenic mutation than the low-PRGS group. CONCLUSIONS: This PRGS could be a powerful and robust tool to improve clinical outcomes for individual gastric cancer patients.

A Celastrol Drug Delivery System Based on PEG Derivatives: The Structural Effects of Nanocarriers.

The therapeutic efficacy of nanoscale drug delivery systems is related to particle size, zeta potential, morphology, and other physicochemical properties. The structure and composition of nanocarriers may affect their physicochemical properties. To systematically evaluate these characteristics, three analogues, namely polyethylene glycol (PEG), PEG-conjugated octadecylamine (PEG-C18), and tri(ethylene glycol) (TEG), were explored as nanocarriers to entrap celastrol (CSL) via the injection-combined dialysis method. CSL nanoparticles were successfully prepared as orange milky solutions, which revealed a similar particle size of approximately 120 nm, with narrow distribution and a negative zeta potential of -20 mV. All these CSL nanoparticles exhibited good storage stability and media stability but presented different drug-loading capacities (DLCs), release profiles, cytotoxicity, and hemolytic activity. For DLCs, PEG-C18/CSL exhibited better CSL entrapment capacity. Regarding the release profiles, TEG/CSL showed the lowest release rate, PEG-C18/CSL presented a moderate release rate, and PEG/CSL exhibited a relatively fast release rate. Based on the different release rates, PEG-C18/CSL and TEG/CSL showed higher degrees of cytotoxicity than PEG/CSL. Furthermore, TEG/CSL showed the lowest membrane toxicity, and its hemolytic rate was below 20%. These results suggest that the structural effects of nanocarriers can affect the interactions between nanocarriers and drugs, resulting in different release profiles and antitumor activity.

Explosive Characteristics and Kinetic Mechanism of Methane-Air Mixtures under High-Temperature Conditions.

In the gas extraction and utilization process of coal mines, gas (mainly containing methane) explosion accidents happen occasionally under high-temperature conditions, causing serious casualties and economic losses. To reveal the mechanism and risk evolution of methane explosion under high-temperature conditions and control such accidents, the explosive characteristics of methane at 25∼200 °C were experimentally investigated by establishing a test platform for gas explosion under high-temperature conditions. In the experiments, three conditions were considered: the concentration near the upper explosion limit (CNUEL) (15.47 vol %), stoichiometric concentration (SC), and concentration near the lower explosion limit (4.68 vol %). Furthermore, the explosion pressure of methane-air mixtures and sensitivity characteristics of key free radicals at different high temperatures were determined based on the GRI-Mech 3.0 reaction mechanism of methane and using software CHEMKIN-PRO. The results show that at SC, P max decreases, while (DP/DT)max remains unchanged as the temperature increases, indicating a gradual decrease in the explosion risk. Near the explosion limits, P max and (DP/DT)max both grow as an exponential function, which implies that the explosion risk gradually increases. The temperature rise exerts a greater effect in improving the risk of explosion overpressure of methane at CNUEL (15.47 vol %), and compared with P max, the temperature rise has a greater improvement effect on (DP/DT)max. In the early stage of consuming methane, methane at SC mainly has two chemical reaction paths: CH4 → CH3 → CH3O → CH2O → HCO → CO and CH4 → CH3 → HCO → CO. The former and the latter to some extent separately promote and inhibit the explosive reactions. As the temperature increases, the proportion of methane consumed by the former reduces, while that by the latter slightly increases. The temperature rise inhibits the increase in the explosion risk of methane at SC, which is consistent with the experimental results.

Influence of High Sulfate Mine Water on Spontaneous Combustion of Coal.

Mine water cannot be discharged until it has been treated, which increases the cost of mining and causes environmental damage. This paper attempted to use sulfate mine water as a flame retardant material for the treatment of coal spontaneous combustion (CSC) in underground mines. The temperature-programed experimental device and gas chromatograph were used to simulate the low-temperature oxidation process of coal. Infrared spectroscopy was used to study the influence and inhibition mechanism of mine water and chloride inhibitor on active functional groups. It was found that although the sulfate mine water inhibited the formation of -OH, it accelerated the cleavage of the aromatic ring. The thermogravimetric experiment was used to analyze the ignition temperature and activation energy of different coal samples. It was found that mine water had an obvious effect on inhibiting CSC in the combustion stage, which could increase the oxidation temperature of coal.

Examination of the microstructures of the lower cervical facet based on micro-computed tomography: A cadaver study.

The cervical facet has complicated 3D microstructures and inhomogeneities. The cervical facet joint, which also participates in the formation, plays a certain role in regulating and limiting the movement of the spine. Correct identification and evaluation of its microstructure can help in the diagnosis of orthopedic disease and predict early phases of fracture risk. To evaluate the safety of the cervical spine by measuring and analyzing the microstructures and morphometric parameters of bone trabeculae in the normal cervical facet with high-resolution 3D micro-computed tomography. Thirty-one sets of C3 to C7 lower cervical vertebrae (155 vertebrae) were scanned using micro-computed tomography. The morphological characteristics and direction of trabecular bone in the facet of the lower cervical vertebrae were observed by selecting and rebuilding the areas of interest, and the changes in the microstructure of the areas of interest were calculated to reveal the structural characteristics and weak areas. Images indicated an ossified center between the superior and inferior articular processes of the lower cervical spine. The cellular bone trabeculae of the articular process had complex reticular microstructures. The trabecular bone plate near the cortical bone was lamellar and relatively dense, and it extended around and transformed into a network structure, and then into the rod-shaped trabecular bone. The rod-shaped trabeculae converged with the plate-shaped trabeculae with only 1 to 2 layers surrounding the trabeculae cavity. Statistical results of the morphological parameters of the trabecular bone showed that trabecular bone volume fraction values were significantly higher for C7 than for C3 to C6 (P < .05). There were significant differences between C7 and C3 to C5 and between C6 and C4 in bone surface area/bone volume (P < .05). There was a significant difference between C7 and C3 to C6 in trabecular bone thickness values (P < .05). The degree of anisotropy value was significantly smaller for C3 than for C6 and C7 (P < .05). The changes in the C3 to C7 microstructure were summarized in this study. The loading capacity and stress of the C7 articular process tended to be limited, and the risk of injury tended to be higher for the C7 articular process.

Research on the Relationship Between Meckel's Cavity Shape, Balloon Shape, and Intracapsular Pressure During Percutaneous Balloon Compression.

OBJECTIVE: Percutaneous balloon compression is a safe, effective, and minimally invasive therapeutic method for trigeminal neuralgia. Intraoperatively precise compression after the formation of the pear-shaped balloon is the key to the expected effect. In this study, we assessed the relationship between the structure of Meckel's cavity and the shape and intracapsular pressure of the balloon by preoperative magnetic resonance. METHODS: We respectively analyzed 58 patients with typical trigeminal neuralgia who underwent percutaneous balloon compression surgery in our department. Reconstruction of magnetic resonance imaging 3-dimensional fast imaging employing steady-state acquisition thin-layer scanning sequence was also performed before the operation to analyze the sagittal features of Meckel's cavity. The pressure was recorded continuously when a pear-shaped balloon was forming during the operation. Meanwhile, the balloon height/length (h/l) ratio was measured. The relationship between Meckel's cavity shape, balloon shape, and pressure was analyzed by mentioned parameters. RESULTS: The pain of 57 patients was relieved immediately after the operation, and the effective rate was 98.27% (57 of 58); Recurrence in 2 cases within the median follow-up time (7.5 months). Meckel's cavity classification on magnetic resonance showed that the clubbing type, oval type, and flat type accounted for 31.1% (18 of 58), 58.6% (34 of 58), and 10.3% (6 of 58), respectively. The results demonstrated that the intracapsular pressure was low, while the h/l ratio of Meckel's cavity was relatively high. We also found the corresponding pressure results when the ratio was low. However, no significant difference was found between the balloon h/l ratio and Meckel's cavity h/l ratio. CONCLUSIONS: Intracapsular pressure of balloon is negatively correlated with the h/l ratio of Meckel's cavity. The individually differentiated formation of the pear-shaped balloon has little correlation with the sagittal shape of Meckel's cavity.

Effects of Multi-Pass Turning on Stress Corrosion Cracking of AISI 304 Austenitic Stainless Steel.

Austenitic stainless steels are extensively used in mechanical engineering. The machined surface integrity has an essential influence on the stress corrosion cracking (SCC) performance of stainless steels. In this paper, the effects of multi-pass turning on the SCC susceptibility of AISI 304 austenitic stainless steel were investigated by correlating the SCC crack density to the machining-induced surface characteristics in terms of roughness, micro-hardness, and residual stress. In the multi-pass turning, the surface roughness and residual stress were the least after the double pass turning, and the surface micro-hardness was the maximum after the triple-pass turning. The SCC susceptibility was evaluated after SCC tests in boiling MgCl2 solution. The results showed that the weakest SCC sensitivity was observed in double-pass turning 304 stainless steel, while the most susceptible SCC was found in triple-pass turning. Compared with the double-pass turning, the increase in SCC sensitivity of triple-pass turning was attributed to the larger roughness, higher micro-hardness and greater residual tensile stresses.

Unclonable human-invisible machine vision markers leveraging the omnidirectional chiral Bragg diffraction of cholesteric spherical reflectors.

The seemingly simple step of molding a cholesteric liquid crystal into spherical shape, yielding a Cholesteric Spherical Reflector (CSR), has profound optical consequences that open a range of opportunities for potentially transformative technologies. The chiral Bragg diffraction resulting from the helical self-assembly of cholesterics becomes omnidirectional in CSRs. This turns them into selective retroreflectors that are exceptionally easy to distinguish-regardless of background-by simple and low-cost machine vision, while at the same time they can be made largely imperceptible to human vision. This allows them to be distributed in human-populated environments, laid out in the form of QR-code-like markers that help robots and Augmented Reality (AR) devices to operate reliably, and to identify items in their surroundings. At the scale of individual CSRs, unpredictable features within each marker turn them into Physical Unclonable Functions (PUFs), of great value for secure authentication. Via the machines reading them, CSR markers can thus act as trustworthy yet unobtrusive links between the physical world (buildings, vehicles, packaging,…) and its digital twin computer representation. This opens opportunities to address pressing challenges in logistics and supply chain management, recycling and the circular economy, sustainable construction of the built environment, and many other fields of individual, societal and commercial importance.