Fabrication and Characterization of Carrageenan/ZnO/Chitosan Composite Films.

In this study, a high-performance carrageenan/ZnO/chitosan composite film (FCA/ZnO/CS) was fabricated by the solution/dispersion casting method and layer-by-layer method. The first layer was nano-ZnO dispersed in carrageenan solution, and the second layer was chitosan dissolved in acetic acid. The morphology, chemical structure, surface wettability, barrier properties, mechanical properties, optical properties, and antibacterial activity of FCA/ZnO/CS were evaluated compared with a carrageenan film (FCA) and carrageenan/ZnO composite film (FCA/ZnO). This study revealed that the Zn element in FCA/ZnO/CS existed in the form of Zn2+ in FCA/ZnO/CS. There existed electrostatic interaction and hydrogen bonding between CA and CS. As a result, the mechanical strength and transparency of FCA/ZnO/CS were enhanced and the water vapor transmittance of FCA/ZnO/CS was decreased compared with that of FCA/ZnO. Furthermore, the addition of ZnO and CS greatly enhanced the antibacterial activity of Escherichia coli and also had a certain inhibitory effect on Staphylococcus aureus. FCA/ZnO/CS is expected to be a potential candidate material for food packaging, wound dressings, and various surface antimicrobial coatings.

Long non-coding RNA expression profiles in neutrophils revealed potential biomarker for prediction of renal involvement in SLE patients.

OBJECTIVE: The long non-coding RNA plays an important role in inflammation and autoimmune diseases. The aim of this study is to screen and identify abnormally expressed lncRNAs in peripheral blood neutrophils of SLE patients as novel biomarkers and to explore the relationship between lncRNAs levels and clinical features, disease activity and organ damage. METHODS: RNA-seq technology was used to screen differentially expressed lncRNAs in neutrophils from SLE patients and healthy donors. Based on the results of screening, candidate lncRNA levels in neutrophils of 88 SLE patients, 35 other connective disease controls, and 78 healthy controls were qualified by real-time quantitative polymerase chain reaction. RESULTS: LncRNA expression profiling revealed 360 up-regulated lncRNAs and 224 down-regulated lncRNAs in neutrophils of SLE patients when compared with healthy controls. qPCR assay validated that the expression of Lnc-FOSB-1:1 was significantly decreased in neutrophils of SLE patients when compared with other CTD patients or healthy controls. It correlated negatively with SLE Disease Activity Index 2000 (SLEDAI-2K) score (r = -0.541, P < 0.001) and IFN scores (r = -0.337, P = 0.001). More importantly, decreased Lnc-FOSB-1:1 expression was associated with lupus nephritis. Lower baseline Lnc-FOSB-1:1 level was associated with higher risk of future renal involvement (within an average of 2.6 years) in patients without renal disease at baseline (P = 0.019). CONCLUSION: LncRNA expression profile in neutrophils of SLE patients revealed differentially expressed lncRNAs. Validation study on Lnc-FOSB-1:1 suggest that it is a potential biomarker for prediction of near future renal involvement.

Preparation of Ion-Exchanged TEMPO-Oxidized Celluloses as Flame Retardant Products.

Cellulose, as one of the most abundant natural biopolymers, has been widely used in textile industry. However, owing to its drawbacks of flammability and ignitability, the large-scale commercial application of neat cellulose is limited. This study investigated some TEMPO-oxidized cellulose (TOC) which was prepared by selective TEMPO-mediated oxidation and ion exchange. The prepared TOC was characterized by Fourier transform infrared (FT-IR) spectroscopy and solid-state 13C-nuclear magnetic resonance (13C-NMR) spectroscopy. The thermal stability and combustion performance of TOC were investigated by thermogravimetry analysis (TG), microscale combustion calorimetry (MCC) and limiting oxygen index (LOI). The results demonstrated that the thermal stability of TOC was less than that of the pristine material cellulose, but the peak of heat release rate (pHHR) and the total heat release (THR) of all TOC were significantly reduced. Additionally, the LOI values of all TOC products were much higher 25%. In summary, the above results indicated that the modified cellulose with carboxyl groups and metal ions by selective oxidation and ion exchange endows efficient flame retardancy.

Prokaryotic expression and functional analysis of the Mb1514 gene in Mycobacterium bovis.

The ability of mycobacteria to grow and invade target tissues is the key component in the process of Mycobacterium bovis infection. Therefore, analysis of the proteins responsible for cell invasion will assist clinicians in combating bovine tuberculosis. The Mb1514 gene of M. bovis encodes a hypothetical invasion protein (designated here as MbINV protein), whose function has not yet been directly identified. In this study, the Mb1514 gene from M. bovis was cloned, and expressed in E. coli. The recombinant MbINV protein (a single band of approximately 28 kDa) was purified for biological analysis. Our data demonstrated that recombinant MbINV protein significantly inhibited the viability of RAW264.7 macrophages in a dose-dependent manner (P < 0.05), and induced cell necrosis, indicating that the protein is toxic. MbINV protein infection significantly enhanced the mRNA expression levels of TNF-α, IL-1ß, and NOS2 (P < 0.01), suggesting that MbINV protein may be one of the virulence factors which directly interact with macrophages and modulate the host immune response to M. bovis. An invasion inhibition assay showed that MbINV-inhibited M. bovis invasion of RAW264.7 cells in a concentration-dependant manner, demonstrating it is an invasion protein.

3D density imaging using gravity and gravity gradient in the wavenumber domain and its application in the Decorah.

Density imaging is a method that uses the inversion of the gravity and gravity gradient spectra in the wavenumber domain to create accurate 3D reconstructions of subsurface density distributions. This approach offers computational efficiency and rapid calculations. This research used preliminary inversions to examine the spectral characteristics of gravity and gravity gradient anomalies, as well as the resulting models, were scrutinized through preliminary inversions. 3D density imaging of gravity and gravity gradient was performed in the wavenumber domain using depth weighting on both noise-added and theoretical data, producing a density model that was consistent with the theoretical one. The technique was then used in the Decorah region of the United States, where 3D density imaging was performed and an examination of the properties of gravity and gravity gradient anomalies was conducted. The results showed where high-density Decorah complexes, low-density siliceous intrusive rocks, and high-density intrusive rock masses, were the distributed within the surrounding rock. Each of these provided comprehensive insights into the intrusive pathways to the rock mass. Thus, the appropriateness and effectiveness of the density imaging method were confirmed, supporting a deeper understanding of the structural division and geological evolution in the region.

Effect of the pre-crosslinking of Ba2+ ions on wet spinning of agar fibers.

Decreased coagulation bath concentration and difficult recovery are classical issues observed during the wet spinning of fibers. In this paper, a novel method was presented for preparing environment-friendly agar fibers using deionized water as the coagulation and stretch baths. The addition of Ba2+ into the spinning solution increased the crosslinking time and improved the performance of spinning solution. The results showed that the introduction of Ba2+ in the spinning solution increased the viscosity of the spinning solution. Particularly, when the concentration of BaCl2 in the spinning solution was 7 wt%, the viscosity increased to 39.29 Pa·s, which made the molecular chain arrangement of agar more compact and ordered and promoted the gelation transformation of the spinning solution, resulting in an increase in the gel temperature from 0.2 °C (Ba-0/agar) to 5.4 °C (Ba-7/agar). The spinning solution was more conducive to the formation of fibers in deionized water. In addition, the physical and chemical properties of agar fibers were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, tensile testing, and scanning electron microscopy. The results showed that the use of deionized water as the coagulation bath can improve the color of fiber and solve the problem of fiber adhesion, whereas the mechanical strength of agar fibers with pre-cross-linking metal ions was also improved. For example, the breaking strength of Ba-7/agar/DIW was 0.73 cN/dtex while the breaking strength of Ba-0/agar/DIW was only 0.62 cN/dtex.

Depth distribution of Moho model and tectonic patterns in South China Sea and adjacent areas.

This study aims to investigate the depth distribution of Mohorovicic discontinuity (Moho) and its relationship with the tectonic pattern of the South China Sea and adjacent areas. To achieve this, the spatial characteristics of the full tensor gravity gradient data are analyzed to identify 17 large and deep faults and to divide the study area into 9 tectonic units with distinct geological structures. Using a three-dimensional (3D) interface inversion method, the Moho depth is determined, constrained by the Moho depth information obtained from sonar-buoy detection and submarine seismograph detection profiles. By analyzing the relationship between the distribution characteristics of Moho and tectonic units, the study summarizes the trend, relief, gradient of Moho, and crustal properties in the study area. Additionally, the seismically constrained Moho undulation combined with the gravity data, gravity gradient anomalies and unconstrained 3D correlation imaging are employed to study the crustal structure of the South China Sea, investigate the vertical and horizontal changes of the crustal structure, and reveal the large-scale crustal and regional structure of the South China Sea. Through the coupling analysis of shallow and deep structures, the study reveals that the gravity gradient anomalies and 3D correlation imaging are consistent with the variations of the Moho depth, indicating the presence of a trench-island arc-back arc basin system and the distribution of continental crust, oceanic crust, and transitional crust in the South China Sea.

Ultrasonographic manifestations and the effective diagnosis of epididymal leiomyosarcoma: Case report and systematic literature review.

Background: Epididymal leiomyosarcoma is an extremely rare tumor. In this study, we describe the sonographic features of this uncommon tumor. Methods: A case of epididymal leiomyosarcoma diagnosed at our institute was retrospectively analyzed. Ultrasonic images, noted clinical manifestations, treatment procedures, and pathology results were collected for this patient. The same information was collected from a systematic literature search on epididymal leiomyosarcoma, including the PUBMED, Web of Science and Google Scholar databases. Results: The literature search resulted in 12 articles; we were able to extract data from 13 cases of epididymal leiomyosarcomatosis. The median patient age was 66 (35-78) years, and the average tumor diameter was 2-7 cm. All patients had unilateral epididymal involvement. The lesions were all solid, irregular-shaped in almost half of the cases, featured clear borders in six cases, and had unclear borders in four cases. The internal echogenicity was heterogeneous in the majority of lesions: six cases were hypoechoic (7/11) and three cases moderately echoic (3/10). Information on blood flow within the mass was provided in four cases, but all were noted with significant vascularity. Surrounding tissue invasion was discussed in 11 cases, with 4 featuring peripheral invasion or metastasis. Conclusion: Epididymal Leiomyosarcoma demonstrates sonographic characteristics common to many malignant tumors, such as increased density, irregular shape, heterogeneous internal echogenicity, and hypervascular. Ultrasonography is helpful to differentiate benign epididymal lesions, and can provide some reference for clinical diagnosis and treatment. However, compared with other malignant tumors of the epididymis, it has no characteristic sonographic features,and pathological confirmation is required.

Comparison of the efficacy and safety of the adalimumab biosimilar TQ-Z2301 and adalimumab for the treatment of Chinese patients with active ankylosing spondylitis: a multi-center, randomized, double-blind, phase III clinical trial.

OBJECTIVE: To assess the clinical equivalence of TQ-Z2301, a biosimilar of adalimumab, to the reference adalimumab in the treatment of Chinese patients with active ankylosing spondylitis. METHODS: This multicenter, randomized, double-blind, positive-controlled phase III clinical trial was conducted in 19 centers across China. Chinese adults with active ankylosing spondylitis despite being treated with non-steroidal anti-inflammatory drugs for ≥ 4 weeks were randomized in a 1:1 ratio to subcutaneously receive 40 mg of TQ-Z2301 or adalimumab every other week for 24 weeks. The primary endpoint was the percentage of patients who achieved at least 20% improvement according to the Assessment of Spondyloarthritis International Society criteria (ASAS20) at week 24. The equivalence was established if the 90% CI for RR of ASAS20 between two groups at week 24 fell within (0.80, 1.25). Secondary endpoints included efficacy measures of disease activity, spinal mobility, physical function and quality of life, immunogenicity, and pharmacokinetic parameters. Safety analysis was done for all patients who received at least one study drug. RESULTS: A total of 380 patients were enrolled in the study between September 2018 and October 2019, including 188 in the TQ-Z2301 group and 192 in the adalimumab group. In the full analysis population, the ASAS20 response rate at week 24 was 86.70% in the TQ-Z2301 group, and 80.73% in the adalimumab group, the RR of ASAS20 for TQ-Z2301 versus adalimumab was 1.074, 90% CI (0.997, 1.157), fell within the predefined equivalence boundary (0.80, 1.25). Except for the SF-36 at week 12, there was no statistical difference between the two groups for all the secondary endpoints (P>0.05). The incidence of adverse events group was 82.45% in the TQ-Z2301, and 83.85% in the adalimumab group, the safety profile of the two groups was similar. The profiles of immunogenicity and pharmacokinetics were also similar between the two groups. CONCLUSION: TQ-Z2301 is equivalent to adalimumab for the treatment of Chinese patients with active ankylosing spondylitis. The safety, immunogenicity, and pharmacokinetic characteristics of both drugs are similar. TRIAL REGISTRATION: The study (CTR20181863) was registered in the Chinese Clinical Trial Registry on 19 October 2018. Key Points • TQ-Z2301 showed the equivalence of efficacy compared with the reference adalimumab for the treatment of Chinese patients with active ankylosing spondylitis. • The safety, immunogenicity, and pharmacokinetics profiles of TQZ-2301 were similar to those of the reference adalimumab.

[Expression of phosphatase and tensin homolog in lower rectal cancer on neoadjuvant chemoradiotherapy].

OBJECTIVE: To explore the expression of phosphatase and tensin homolog deleted on chromosome ten (PTEN) in low rectal cancer on neoadjuvant chemoradiotherapy with capecitabine plus radiotherapy. METHODS: Sixty-six patients with low rectal cancer on therapy with capecitabine (1650 mg×m(-2)×d(-1) in 2 divided doses) for two course and concurrent radiotherapy (50 Gy, 2 Gy/day, 5 days a week). Then the investigators analyzed the relationship between the preoperative neoadjuvant chemoradiotherapy and prognosis and measured the expression of PTEN during neoadjuvant chemoradiotherapy. RESULTS: 92.4% (61/66) of patients received neoadjuvant chemoradiotherapy as planned. 87.9% (58/66) tumor stages were down-staged, tumor size decreased while the distance from anal edge increased. And curative resection with sphincter-sparing was carried out in all patients. The rate of sphincter preservation was 90.9% (60/66). Among which, 85.5% patients showed an excellent function of sphincter. The 2-year survival rate was 87.9% (58/66). The survival period was an average of 35.3 months (range: 25-60). The PTEN mRNA and protein expression in cancer tissues on neoadjuvant chemoradiotherapy were significantly higher than those before neoadjuvant chemoradiotherapy (P=0.0079, 0.0269). CONCLUSIONS: The preoperative neoadjuvant chemoradiotherapy in lower rectal cancer patients has shown its efficacy in down-staging cancer, enhancing resectability, offering sphincter preservation, up-regulating PTEN expression, promoting the apoptosis of cancer cell and achieving a better survival rate. Thus preoperative neoadjuvant chemoradiotherapy is an effective adjuvant measure.

High-strength carrageenan fibers with compactly packed chain structure induced by combination of Ba2+ and ethanol.

Carrageenan fibers have attractive applications in textile, but their low strength remains a problem that needs to be urgently addressed. In this work, a novel facile, environmental friendly method for fabricate high-strength carrageenan fibers is proposed. It involves the crosslinking of a small amount of Ba2+ ions in the carrageenan solution, followed by using recyclable alcohol in coagulation and stretching baths. Carrageenan molecular chains were allowed to first sufficiently interact with metal barium ions, and then were stretched and dehydrated with alcohol to increase the hydrogen bonding interaction between the molecular chains. As a result, the carrageenan fibers with high-strength ionic and hydrogen bonds were obtained. The fibers obtained by the novel method had high tensile strength at 1.63 cN/dtex, which is two times higher than that of those obtained by the traditional process.

Comparison of Two Different Preparation Methods of Wet-Spun Carrageenan Fibers Directly from Chondrus Extractions.

In order to improve the characters of carrageenan fibers, two different process methods were presented in this study. Dopes prepared directly from Chondrus extraction by Route A-adding NaOH after Chondrus extraction-or Route B-using NaOH solution to extract Chondrus and carrageenan fibers (Fibers A and Fibers B)-were obtained using the wet spinning process using barium chloride as the coagulant at room temperature. The properties of dopes were studied by dynamic light scattering and gel permeation chromatography. The properties of Fibers A and Fibers B were comprehensively studied by Fourier transform infrared, thermal analysis, scanning electron microcopy, and tensile testing. The results showed that carrageenan with a larger molecule weight in Dope A and Fibers A showed higher intensity, better morphology, and stable thermal properties.

Preparation of CdTe/Alginate Textile Fibres with Controllable Fluorescence Emission through a Wet-Spinning Process and Application in the Trace Detection of Hg2+ Ions.

Fluorescent textile fibres (FTFs) are widely used in many industrial fields. However, in addition to fibres with good fluorescence, fibres with excellent colour controllability, structural stability and appropriate mechanical strength still need to be developed. In this work, CdTe/alginate composite FTFs are prepared by taking advantage of the interactions between CdTe nanocrystals (NCs) and alginate macromolecules via a wet-spinning machine with a CaCl2 aqueous solution as the coagulation bath. CdTe NCs were chemically fixed in the fibre due to the interactions among surface ligands, macromolecules and coagulators (calcium ions), which ensured the excellent dispersity and good stability of the fibres. Förster resonance energy transfer (FRET) between NCs in the fibre was found to be restricted, which means that the emission colour of the fibres was totally controllable and could be predicted. Other properties of alginate fibres, such as flame retardance and mechanical strength, were also well preserved in the fluorescent fibres. Finally, FTFs showed good selectivity toward trace Hg2+ ions over other metallic ions, and the detection could be identified by the naked eye.

Effect of SiO2 nanoparticle on the physical and chemical properties of eco-friendly agar/sodium alginate nanocomposite film.

Agar/sodium alginate (AG/SA) nanocomposite films were prepared using solution casting method in presence of various concentrations of nano-SiO2 (2.5, 5, 7.5, and 10 wt%). The effect of nano-SiO2 concentration on the nanocomposite film was investigated. The result of Fourier transform infrared (FTIR) illustrated the formation of hydrogen bonding between nano-SiO2 and polysaccharide. As nano-SiO2 concentration rose from 0 to 10 wt%, the tensile strength and elongation at break all increased up to maximum, respectively. The tensile strength and elongation at break of film containing 10 wt% nano-SiO2 increased by 65.29% and 60.38% respectively when compared to those of film prepared without nano-SiO2. The reason for enhancing in tensile strength might be related to the formation of molecular interaction. The film containing 2.5 wt% nano-SiO2 had maximum water contact angle and minimum water vapor permeability among those of all films prepared in this work. However, the film containing 10 wt% nano-SiO2 had minimum swelling degree and water solubility, further demonstrating the formation of strong interaction. The addition of nano-SiO2 improved the properties of film against UV light and thermal stability. Overall, the addition of nano-SiO2 enhanced the mechanical properties, water resistance and thermal stability of polysaccharide film.

Study on the preparation and flame retardant properties of an eco-friendly potassium-calcium carrageenan fiber.

Potassium-calcium carrageenan fibers were prepared in an eco-friendly fashion by wet spinning method. The forming process and flame retardant properties of this fiber compared with the traditional barium carrageenan fibers were studied in this paper. The results showed that the potassium ions were combined with the sulfate group in the carrageenan by ion bonding that made the potassium-calcium carrageenan fibers form a gel structure, which was a relative loose spatial network, while barium ions reacted with the sulfate groups of carrageenan to induce barium carrageenan fibers form a precipitated structure, which was a relative close spatial network. The limiting oxygen index, cone calorimeter, thermogravimetric analysis and pyrolysis-gas chromatography-mass spectrometry tests implied that K+-Ca2+ affected the pyrolysis behavior of potassium-calcium carrageenan fibers and catalyzed it to produce different pyrolysis products from Ba2+ in barium carrageenan fibers. In addition, the pyrolysis mechanism of potassium-calcium carrageenan fibers was elucidated in this paper.

Cooking-Inspired Versatile Design of an Ultrastrong and Tough Polysaccharide Hydrogel through Programmed Supramolecular Interactions.

Simultaneously achieving strength and toughness in soft materials remains a challenge, especially for physically crosslinked hydrogels with many inactive interaction sites. In this work, inspired by the cooking of thick soup in China, a facile method that includes free water evaporation of the diluted pregel solution followed by crosslinking (WEC) is proposed to fabricate polysaccharide hydrogels. Herein, without the constraints of viscosity and crosslinking, polymer chains can homogenously approach as much as possible, thereby enabling the transformation of inactive supramolecular interaction (H-bonding and ionic coordination) sites into active sites until reaching the maximum level. Through facilely tuning the concentrating degree, programmed supramolecular interactions, serving as energy-dissipating sacrificial bonds, impart the hydrogels with strength and toughness over a very wide range, where a "ductile-to-tough" transition is discovered to occur first. Using WEC in alginate, the concentration can be as high as 25 wt% without sacrificing processing ability, a result that is significantly beyond common value (3-7 wt%), and the extremely stiff and tough hydrogels are obtained, superior to isotropic alginate hydrogels ever reported. This research offers a facile and versatile strategy to fabricate isotropic polysaccharide hydrogels, which become ideal matrix materials for further fabrication of hybrid or anisotropic hydrogels.

Identification of Renal Long Non-coding RNA RP11-2B6.2 as a Positive Regulator of Type I Interferon Signaling Pathway in Lupus Nephritis.

Objective: Lupus nephritis (LN) is one of the most serious complications of systemic lupus erythematosus (SLE). Type I interferon (IFN-I) is associated with the pathogenesis of LN. Long non-coding RNAs (lncRNAs) have been implicated in the pathogenesis of SLE, however, the roles of lncRNAs in LN are still poorly understood. Here, we identified and investigated the function of LN-associated lncRNA RP11-2B6.2 in regulating IFN-I signaling pathway. Methods: RNA sequencing was used to analyze the expression of lncRNAs in kidney biopsies from LN patients and controls. Antisense oligonucleotides and CRISPRi system or overexpression plasmids and CRISPRa system were used to perform loss or gain of function experiments. In situ hybridization, imaging flow cytometry, dual-luciferase reporter assay, and ATAC sequencing were used to study the functions of lncRNA RP11-2B6.2. RT-qPCR, ELISA, and western blotting were done to detect RNA and protein levels of specific genes. Results: Elevated lncRNA RP11-2B6.2 was observed in kidney biopsies from LN patients and positively correlated with disease activity and IFN scores. Knockdown of lncRNA RP11-2B6.2 in renal cells inhibited the expression of IFN stimulated genes (ISGs), while overexpression of lncRNA RP11-2B6.2 enhanced ISG expression. Knockdown of LncRNA RP11-2B6.2 inhibited the phosphorylation of JAK1, TYK2, and STAT1 in IFN-I pathway, while promoted the chromatin accessibility and the transcription of SOCS1. Conclusion: The expression of lncRNAs is abnormal in the kidney of LN. LncRNA RP11-2B6.2 is a novel positive regulator of IFN-I pathway through epigenetic inhibition of SOCS1, which provides a new therapeutic target to alleviate over-activated IFN-I signaling in LN.

Preparation and properties of wet-spun agar fibers.

Motivated by the extensive application of agar, this work developed a wet-spinning process to fabricate micro-scale fibers using the gelation process of agar. The effect of three vital spinning parameters, namely dope concentration, coagulation bath composition, and fiber post-processing on morphological properties, tensile properties and chemical structure of the fiber have been discussed. The concentration of agar was determined by the results of rheological measurement. The addition of barium chloride in the coagulation process improved the mechanical properties of fibers as compared to deionized water as coagulation. The agar fibers immersed in amino silicone demonstrated significantly showed better mechanical properties compared to the agar fibers only immersed in ethanol. The physical and chemical properties of agar fibers were characterized by X-ray diffraction, FTIR, tensile testing, and SEM. The results showed that excellent agar fibers with several potential applications can be produced with amino silicone modification in optimum coagulation bath.

Preparation of carrageenan fibers with extraction of Chondrus via wet spinning process.

Traditionally, the carrageenan fibers were prepared by process of extracting, drying, dissolving of carrageenan power and wet spinning process of fibers. However, in this study, carrageenan fibers were prepared by carrageenan solution directly from the extraction of Chondrus, without the steps of precipitation, and drying. The properties of carrageenan powder, spinning solution and carrageenan fibers were characterized with zeta potential, NMR, FTIR, dynamic light scattering (DLS), SEM, tensile testing and energy dispersive spectrometer (EDS). The results showed that the Chondrus contained mainly iota-carrageenan. The extraction of Chondrus was a uniform liquid with good properties of a solution, which was suitable as a spinning solution. The so prepared carrageenan fibers possessed good morphology and tensile properties. The excellent tensile properties of the carrageenan fibers were attributed to the combination of sulfate ester in the carrageenan and barium ions in the coagulation and then form a three-dimensional network structure.