Phosphorus/Bromine Synergism Improved the Flame Retardancy of Polyethylene Terephthalate Foams.

Polyethylene terephthalate (PET) foams have the characteristics of being lightweight and high strength, as well as offering good heat resistance, minimal water absorption, etc., and they have been widely used in the wind power field. In addition, they are being promisingly applied in automotive, rail, marine, construction, and other related fields. Therefore, the flame retardancy(FR) of PET foams is an issue that requires investigation. The addition of flame retardants would affect the chain extension reaction, viscoelasticity, and foamability of PET. In this study, zinc diethyl hypophosphite (ZDP) and decabromodiphenylethane (DBDPE) were used to form a synergistic FR system, in which ZDP is an acid source and DBDPE is a gas source, and both of them synergistically produced an expanded carbon layer to improve the flame retardancy of PET foams. The ratio of ZDP and DBDPE is crucial for the carbon yield and the expansion and thermal stability of the char layers. At the ZDP/DBDPE ratios of 9/3 and 7/5, the thickness of the char layers is about 3-4 mm, the limiting oxygen index (LOI) values of FR modified PET are 32.7% and 33.6%, respectively, and the vertical combustion tests both reached the V-0 level. As for the extruded phosphorous/bromine synergism FR PET foams, ZDP/DBDPE ratios of 3:1 and 2:1 were applied. As a result, the vertical combustion grade of foamed specimens could still reach V-0 grade, and the LOI values are all over 27%, reaching the refractory grade.

Morphology and Compressive Properties of Extruded Polyethylene Terephthalate Foam.

The cell structure and compressive properties of extruded polyethylene terephthalate (PET) foam with different densities were studied. The die of the PET foaming extruder is a special multi-hole breaker plate, which results in a honeycomb-shaped foam block. The SEM analysis showed that the aspect ratio and cell wall thickness of the strand border is greater than that of the strand body. The cells are elongated and stronger in the extruding direction, and the foam anisotropy of the structure and compressive properties decrease with increasing density. The compression results show typical stress-strain curves even though the extruded PET foam is composed of multiple foamed strands. The compression properties of PET foam vary in each of the three directions, with the best performing direction (i.e., extrusion direction) showing stretch-dominated structures, while the other two directions show bending-dominated structures. Foam mechanics models based on both rectangular and elongated Kelvin cell geometries were considered to predict the compressive properties of PET foams in terms of relative density, structure anisotropy, and the properties of the raw polymer. The results show that the modulus and strength anisotropy of PET foam can be reasonably predicted by the rectangular cell model, but more accurate predictions were obtained with an appropriately assumed elongated Kelvin model.

Quantitative assessment of early kidney injury using high frame rate contrast-enhanced ultrasonography in a rabbit model of diabetic nephropathy.

AIM: To explore benefits of high-frame-rate contrast-enhanced ultrasonography (H-CEUS) for early kidney injury in a rabbit model of diabetic nephropathy (DN). METHODS: Diabetic rabbits were induced with alloxan administration and split into 2 groups with or without urinary microalbuminuria after a fatty and sugary diet: diabetic rabbits with nephropathy (Group A) and diabetic rabbits without nephropathy (Group B). The control group (Group C) comprised healthy rabbits. Renal H-CEUS and conventional CEUS (C-CEUS) imaging were conducted. Serum creatinine (SCR), blood urea nitrogen (BUN) and urinary microalbuminuria were measured. RESULTS: SCR and BUN levels were barely changed in Groups B and C (p>0.05), whereas Group A exhibited a rise (p<0.05). Perfusion parameters of the two CEUS modalities showed reduced peak intensity (PI) and ascending slope (AS) and elevated area under the curve (AUC) and time to peak (TTP) in Group A versus Group B (p<0.05) and Group B versus Group C (p<0.05). The arrival time (AT) and descending slope (DS) exhibited little difference among the three groups. H-CEUS had a stronger correlation of perfusion parameters with SCR and BUN than C-CEUS. CONCLUSIONS:  H-CEUS outperforms C-CEUS in diagnosing early renal damage in DN. H-CEUS perfusion parameters demonstrate temporal superiority over routine laboratory indices.

Non-Destructive Determination of Bayberry Sugar and Acidity by Hyperspectral Remote Sensing of Si-Sensor and Low-Cost Portable Instrument Development.

The digitalization of information is crucial for the upgrading of the bayberry digital agriculture industry, while the low-cost information detection sensing equipment for bayberry are a bottleneck for the digital development of the industry. The existing rapid and non-destructive detection devices for fruit acidity and sugar content mainly use near-infrared and mid-infrared spectral characteristic for detection. These devices use expensive InGaAs sensor, which are difficult to promote and apply in the bayberry digital industry. This study is based on the high-spectral range of 454-998 nm in bayberry fruit to study the mechanism of fruit sugar and acidity content detection and to develop a portable bayberry fruit sugar and acidity detection device using Si-sensor in order to achieve low-cost quality parameter detection of bayberry fruit. The research results show that: Based on the hyperspectral of bayberry fruit, the sensitive wavelength for sugar content inversion is 610 nm, and the inversion accuracy (RMSE) is 1.399Brix; the sensitive wavelength for pH inversion is 570 nm, and the inversion accuracy (RMSE) is 0.1329. Based on the above spectroscopic detection mechanism and spectral dimension reduction methods, combined with low-cost Si-sensor (400-1000 nm), a low-cost non-destructive portable bayberry fruit sugar and acidity detection device has been developed, with detection accuracies of 94.74% and 97.14%, respectively. This bayberry fruit sugar and acidity detector provides a low-cost portable non-destructive quality detection instrument of bayberry, which is in line with the industrial group of low consumption in which the bayberry is mainly cultivated on a small scale, accelerating the digitalization process of the bayberry industry.

Study on Chain Extension Blending Modification and Foaming Behavior of Thermoplastic Polyamide Elastomer.

In order to improve the melt foaming properties of thermoplastic polyamide elastomers and reduce the shrinkage rate of foamed materials, acid anhydride chain extenders SMA (styrene maleic anhydride copolymer) are used in this paper to in situ reactive blending thermoplastic polyamide elastomers (TPAE) and polyamide 6 (PA6). The rheological and crystalline properties of the modified samples were characterized by a rotational rheometer and differential scanning calorimeter, and the melt batch foaming experiment with CO2 as the foaming agent was carried out. The results showed that the melting enthalpy of modified TPAE reduced with the addition of content of PA6, which implied that the crystallinity of the hard phase of the system was depressed. Nevertheless, the reduction of crystallinity was beneficial to improve the penetration of gas and reduce the effect of the pressure difference inside and outside the cell on foam shrinkage. Additionally, the microcross-linked structure formed with the increase of PA6 content enhanced the storage modulus of modified TPAE, which could accelerate recovery of strain. The foaming temperature zone and recovery performance of all modified TPAE samples were significantly improved. The overall shrinkage rate was reduced to less than 10%, the maximum expansion ratio could reach 11-13 times with a more complete and uniform cell structure, and the resilience was improved by about 12%.

Identification of Bladder Cancer Subtypes Based on Necroptosis-Related Genes, Construction of a Prognostic Model.

Background: Necroptosis is associated with the development of many tumors but in bladder cancer the tumor microenvironment (TME) and prognosis associated with necroptosis is unclear. Methods: We classified patients into different necroptosis subtypes by the expression level of NRGS (necroptosis-related genes) and analyzed the relationship between necroptosis subtypes of bladder cancer and TME, then extracted differentially expressed genes (DEGS) of necroptosis subtypes, classified patients into different gene subtypes according to DEGS, and performed univariate COX analysis on DEGS to obtain prognosis-related DEGS. All patients included in the analysis were randomized into the Train and Test groups in a 1:1 ratio, and the prognostic model was obtained using the LASSO algorithm and multivariate COX analysis with the Train group as the sample, and external validation of the model was conducted using the GSE32894. Results: Two necroptosis subtypes and three gene subtypes were obtained by clustering analysis and the prognosis-related DEGS was subjected to the LASSO algorithm and multivariate COX analysis to determine six predictors to construct the prognostic model using the formula: riskScore = CERCAM × 0.0035 + POLR1H × -0.0294 + KCNJ15 × -0.0172 + GSDMB × -0.0109 + EHBP1 × 0.0295 + TRIM38 × -0.0300. The results of the survival curve, roc curve, and risk curve proved the reliability of the prognostic model by validating the model with the test group and the results of the calibration chart of the Nomogram applicable to the clinic also showed its good accuracy. Necroptosis subtype A with high immune infiltration had a higher risk score than necroptosis subtype B, gene subtype B with low immune infiltration had a lower risk score than gene subtypes A and C, CSC index was negatively correlated with the risk score and drug sensitivity prediction showed that commonly used chemotherapeutic agents were highly sensitive to the high-risk group. Conclusion: Our analysis of NRGS in bladder cancer reveals their potential role in TME, immunity, and prognosis. These findings may improve our understanding of necroptosis in bladder cancer and provide some reference for predicting prognosis and developing immunotherapies.

Electric-Field-Driven Ion Emission from the Free Surface of Room Temperature Ionic Liquids.

Electric-field-driven ion emission from the free surface of a planar room-temperature ionic liquid (RTIL) film was studied by using molecular dynamics simulations. We calculated ion emission rate (je) as a function of the electric field normal to the RTIL/vacuum surface (En) and found that the logarithm of je over the charge density on the surface (σ) is proportional to En1/2, in agreement with classical ion evaporation theories. The composition of emitted ions includes monomers and dimers. It was found that the monomer has to move across two barriers before emission. The fraction of dimers was found to depend on the external field and ion-ion interactions. We further performed replica exchange molecular dynamics simulations and identified different metastable states of the emitting ion near the liquid film. Our results showed that En and molecular details of ion/surface determine the rate and composition of ion emission from RTIL/vacuum surfaces. Fundamental insights revealed in this study form the basis to improve ion evaporation theories and performance of electrospray applications ranging from space propulsion to nanomanufacturing.

Hepatic adrenal adenoma-rare tumor on right lobe of liver: a case report and literature review.

BACKGROUND: Hepatic adrenal ectopia is a common clinical diagnosis, whereas adrenal tumors developed from hepatic adrenal ectopia are rare. Hepatic adrenal tumors are easily misdiagnosed as hepatic carcinoma and frequently treated by unnecessary operations. CASE PRESENTATION: A 50-year-old female patient was hospitalized due to B-ultrasonic detection of "right focal liver lesions." After hospitalization, enhanced CT examination was performed. A 2.2 cm × 1.8 cm tumor was found in the seventh section of the right liver, as indicated by obvious enhancement of the arterial phase and low density during the portal vein and delay stages. Enhanced MRI examination detected a 2.0 cm × 1.8 cm tumor on the right liver, which was considered a "primary hepatic carcinoma". The patient was treated by open hepatectomy and recovered well after the operation. The postoperative pathological diagnosis was hepatic adrenal adenoma. No relapse was observed through the 1-year follow-up visit. CONCLUSIONS: According to imaging manifestations, pathological immunohistochemical treatment, alpha fetoprotein (AFP) and clinical features, hepatic adrenal tumors should be considered in the diagnosis of hepatic carcinoma to prevent misdiagnosis. Hepatic adrenal tumors should be ruled out during the diagnosis to avoid unnecessary operation.

A novel detection of correlated alarms with delays based on improved block matching similarities.

Statistical analysis method has emerged as a general approach to detect relation alarms in the process industries. However, the delay between related alarms is the main cause leading to wrong analysis results from traditional approaches to detect correlated alarms. This paper proposed a novel detection of correlated alarms based on block matching similarities with delay (BMS-d). First, blocking alarm data sequence method is to transform alarm data into time node sequences, which is able to reduce the calculation burden of the correlation analysis. Second, a novel maximal block correlation coefficient method is presented to estimate the correlation delay between alarms. Third, a novel method is proposed to detect correlated alarms based on the block matching similarities and related alarm delay information. A numerical case and TE process are employed to demonstrate the effectiveness and efficiency of the proposed method.

Double helical conformation and extreme rigidity in a rodlike polyelectrolyte.

The ubiquitous biomacromolecule DNA has an axial rigidity persistence length of ~50 nm, driven by its elegant double helical structure. While double and multiple helix structures appear widely in nature, only rarely are these found in synthetic non-chiral macromolecules. Here we report a double helical conformation in the densely charged aromatic polyamide poly(2,2'-disulfonyl-4,4'-benzidine terephthalamide) or PBDT. This double helix macromolecule represents one of the most rigid simple molecular structures known, exhibiting an extremely high axial persistence length (~1 micrometer). We present X-ray diffraction, NMR spectroscopy, and molecular dynamics (MD) simulations that reveal and confirm the double helical conformation. The discovery of this extreme rigidity in combination with high charge density gives insight into the self-assembly of molecular ionic composites with high mechanical modulus (~ 1 GPa) yet with liquid-like ion motions inside, and provides fodder for formation of other 1D-reinforced composites.

Peptide-guided functionalization and macrocyclization of bioactive peptidosulfonamides by Pd(II)-catalyzed late-stage C-H activation.

Peptides and peptidomimetics are emerging as an important class of clinic therapeutics. Here we report a peptide-guided method for the functionalization and macrocyclization of bioactive peptidosulfonamides by Pd(II)-catalyzed late-stage C-H activation. In this protocol, peptides act as internal directing groups and enable site-selective olefination of benzylsulfonamides and cyclization of benzosulfonamides to yield benzosultam-peptidomimetics. Our results provide an unusual example of benzosulfonamide cyclization with olefins through a sequential C-H activation, which involves the generation of a reactive palladium-peptide complex. Furthermore, this protocol allows facile self-guided macrocyclization of sulfonamide-containing peptides by intramolecular olefination with acrylates and unactivated alkenes, affording bioactive peptidosulfonamide macrocycles of various sizes. Together, our results highlight the utility of peptides as internal directing groups in facilitating transition metal-catalyzed functionalization of peptidomimetics.

Synthesis of bioactive and stabilized cyclic peptides by macrocyclization using C(sp3)-H activation.

Cyclic peptides have attracted increasing attention in recent years due to their ability to inhibit protein-protein interactions. Current strategies to prepare cyclic peptides often rely on functional amino acid side chains or the incorporation of unnatural amino acids, thus limiting their structural diversity. Here, we describe the development of a highly versatile peptide macrocyclization strategy through a palladium-catalyzed C(sp3)-H activation and the synthesis of cyclic peptides featuring unique hydrocarbon linkages between the ß-carbon of amino acids and the aromatic side chains of Phe and Trp. We demonstrate that such peptides exhibit improved biological properties compared to their acyclic counterparts. Finally, we applied this method in the synthesis of the natural product celogentin C.

Molecular Structure and Dynamics of Ionic Liquids in a Rigid-Rod Polyanion-Based Ion Gel.

The recent fabrication of liquid crystalline ion gels featuring rigid-rod polyanions aligned within room-temperature ionic liquids (RTILs) opens up exciting new avenues for engineering ion conducting materials. These gels exhibit an unusual combination of properties including high ionic conductivity, distinct transport anisotropy, and widely tunable elastic modulus. Using molecular simulations, we study the structure and dynamics of the ions in an ion gel consisting of rigid-rod polyanions and [C2mim][TfO] RTILs. We show that the ion distribution in the interstitial space between polymer rods exhibits the hallmarks of the RTIL structure near charged surfaces; i.e., cations (C2mim+) and anions (TfO-) form alternating layers around the polymer rods and the charge on the rod is overscreened by the ionic layer surrounding it. The distinct ordering of ions suggests the formation of a long-range "electrostatic network" in the ion gel, which may contribute to its mechanical cohesion and high modulus. The dynamics of both C2mim+ and TfO- ions slow down due to the fact that some C2mim+ ions become associated with the sulfonate groups of the polymer rod on nanosecond time scales, which hinders the dynamics of all ions in the gel. C2mim+ and TfO- ion diffusion in the gel are only 2-10 times slower than in bulk RTILs, which is still much faster than, e.g., Li ions in typical ion conducting polymers. This fast ion transport combined with strong mechanical cohesion open up exciting opportunities for application of these gels in electrochemical devices including Li-metal batteries.

Importance of Ion Packing on the Dynamics of Ionic Liquids during Micropore Charging.

Molecular simulations of the diffusion of EMIM(+) and TFSI(-) ions in slit-shaped micropores under conditions similar to those during charging show that in pores that accommodate only a single layer of ions, ions diffuse increasingly faster as the pore becomes charged (with diffusion coefficients even reaching ∼5 × 10(-9) m(2)/s), unless the pore becomes very highly charged. In pores wide enough to fit more than one layer of ions, ion diffusion is slower than in the bulk and changes modestly as the pore becomes charged. Analysis of these results revealed that the fast (or slow) diffusion of ions inside a micropore during charging is correlated most strongly with the dense (or loose) ion packing inside the pore. The molecular details of the ions and the precise width of the pores modify these trends weakly, except when the pore is so narrow that the ion conformation relaxation is strongly constrained by the pore walls.

Probing Nanoscale Thermal Transport in Surfactant Solutions.

Surfactant solutions typically feature tunable nanoscale, internal structures. Although rarely utilized, they can be a powerful platform for probing thermal transport in nanoscale domains and across interfaces with nanometer-size radius. Here, we examine the structure and thermal transport in solution of AOT (Dioctyl sodium sulfosuccinate) in n-octane liquids using small-angle neutron scattering, thermal conductivity measurements, and molecular dynamics simulations. We report the first experimental observation of a minimum thermal conductivity occurring at the critical micelle concentration (CMC): the thermal conductivity of the surfactant solution decreases as AOT is added till the onset of micellization but increases as more AOT is added. The decrease of thermal conductivity with AOT loading in solutions in which AOT molecules are dispersed as monomers suggests that even the interfaces between individual oleophobic headgroup of AOT molecules and their surrounding non-polar octane molecules can hinder heat transfer. The increase of thermal conductivity with AOT loading after the onset of micellization indicates that the thermal transport in the core of AOT micelles and across the surfactant-oil interfaces, both of which span only a few nanometers, are efficient.

Dynamic Charge Storage in Ionic Liquids-Filled Nanopores: Insight from a Computational Cyclic Voltammetry Study.

Understanding the dynamic charge storage in nanoporous electrodes with room-temperature ionic liquid electrolytes is essential for optimizing them to achieve supercapacitors with high energy and power densities. Herein, we report coarse-grained molecular dynamics simulations of the cyclic voltammetry of supercapacitors featuring subnanometer pores and model ionic liquids. We show that the cyclic charging and discharging of nanopores are governed by the interplay between the external field-driven ion transport and the sloshing dynamics of ions inside of the pore. The ion occupancy along the pore length depends strongly on the scan rate and varies cyclically during charging/discharging. Unlike that at equilibrium conditions or low scan rates, charge storage at high scan rates is dominated by counterions while the contribution by co-ions is marginal or negative. These observations help explain the perm-selective charge storage observed experimentally. We clarify the mechanisms underlying these dynamic phenomena and quantify their effects on the efficiency of the dynamic charge storage in nanopores.