Effects of Ultraviolet Radiation,High Temperature and Alkaline Chemicals on Ageing of Silicone Sealants Used in Ballastless Track Expansion Joints

Expansion joints silicone sealants used in high speed railway construction suffer from ultraviolet radiation（UV）, high temperature combined with the alkaline environment. To evaluate the durability and analyse the ageing mechanism, six one-component silicone sealants from different companies were selected and subjected to accelerated ageing tests including UV, thermal and alkali ageing treatments. The ageing effects on the performance of the sealants were evaluated via the appearance and the mechanical property changes. The changes in molecular structure were studied by means of Fourier transform infrared spectroscopy（FTIR）, differential scanning calorimetry（DSC） and thermogravimetry（TG）. This study revealed that different materials displayed different sensibilities to the ageing methods, in which 15 %-20 % decreases of mechanical properties could be observed under UV radiation test, owning the most significant effects. Structure analysis showed that the physical changes of aggregative states were the principal factors to the performance, along with the chemical slight changes. The glossiness dropped significantly in ageing test, which could be used as one of the effective evaluation parameters for ageing conditions in the field.

Evaluation and Selection of Sealants and Fillers Using Principal Component Analysis for Cracks in Asphalt Concrete Pavements

The objective of this paper was to develop a comprehensive evaluation method and index to evaluate the performance of sealants and fillers for cracks in asphalt concrete pavements using the method of principal component analysis. The performance experiments including cone penetration, softening point, flow, resilience and tension at low temperature respectively were conducted by reference of ASTM D5329 for eight sealants and fillers often used in China. There by a principal component model was developed and weight of every index was calculated. The experimental results show that there are significantly different performances for sealants and fillers often used in China. Principal component analysis is an objective method that evaluates and selects the performance of sealants and fillers for cracks in asphalt concrete pavements.

The Dynamic Tribological Performance of One Certain Resin-based Friction Materials under Different Temperature Conditions

A fixed-point observation method was designed to research the dynamic tribological performance of one certain resin-based friction materials. The friction test was performed through a constant speed friction tester under various temperature conditions. It was found that the dynamic tribological performance of materials has a good consistency with the dynamic evolution of worn surfaces. At lower temperatures, the friction coefficient and wear rate were constant, resulted from the stable worn surfaces. At higher temperatures, the friction coefficient increased gradually, while the wear rate decreased, due to the increasing contact area and Fe concentration. A fade occurred above 250 ℃, which can be explained by the degradation of binders.

Pancreatic duct disruption and nonoperative management: the SEALANTS approach

Pancreatic-duct disruption (PDD) can be difficult to manage, with diverse etiologies and sequelae in a heterogeneous population. Common etiologies include pancreatitis, iatrogenic injury, and trauma. Sequelae of PDD include pseudocyst, pancreatic ascites,

Synthesis and Application of a Novel Organosilane Modifier for Surface Paintability of Organosiloxane Sealants

A novel organosilane, N-n-butyl-γ-aminopropylmethyldimethoxysilane was synthesized through aminization reaction and the chemical structure of resulting products was characterized by 1HNMR, 13CNMR, FT-IR and elemental analysis. The results of test on probation for this organosilane proved that it was effective to modify surface-paintability of organosiloxane sealants.

Compatibility between glass sealants and electrode materials of solid oxide fuel cells

BaO-CaO-Al2O3-SiO2-La2O3-B2O3 system glass materials were investigated as sealants for a solid oxide fuel cell （SOFC）. The transition temperature （Tg and the crystal temperature （Td） values decrease greatly with the increase of BaCO3 content when the other components do not change. For the thermal expansion coefficient （TEC） values, the trend is inverse. The sealant has superior thermal expansion coefficient matching properties with La（Sr）MnO3 （LSM） cathode, La（Sr）FeO3 （LSF） cathode, Ni-LDC （La doped CeO2） anode, and Ni-YSZ （yttria stabilized zirconia） cermet anode. The sealant also has superior stability, compatibility, and good bonding characteristic with these electrode materials at 800-900℃. The results indicate that the aluminosilicate system glass sealant possesses superior compatibility with electrode materials of the solid oxide fuel cell

Evaluation of Ion Release from Four Dental Sealants

The purpose of this study was to determine the ion release from four commercially available pit-and-fissure sealants [3M Clinpro, 3M ConciseTM, BeautiSealant （BS）, and GI FX-Ⅱ）]. With each brand, 18 specimens were prepared. Their fluoride release in de-ionized water was measured by fluoride electrode, while the release of silicate （Si）, aluminum （A1）, sodium （Na）, calcium （Ca）, strontium （Sr）, and phosphorus （P） was measured by inductively coupled plasma atomic emission spectroscopy （ICP-AES） on days 1, 3, 7, 14, 21, and 28. The result showed that fluoride was not released from 3M ConciseTM. GI FX-II displayed the largest fluoride release, which, however, dropped rapidly on day 3.3M Clinpro exhibited less fluoride release than GI FX-II and BS did. At any time during the 28-day experimental period, GI FX-II released more Na than the other sealants （P〈0.001）. BS ranked the second in Na release, and a small amount of Na ions was released from the 3M Clinpro and 3M ConciseTM samples. Al ions were only detected from BS and GI FX-Ⅱ, but not from the 3M Clinpro and 3M ConciseTM. Additionally GI FX-II had the largest Si release among the four brands at any time during the experimental period （P〈0.001）. Ca ions were detected from 3M Clinpro and 3M ConciseTM, but not from GI FX-Ⅱ. BS released more Sr than the other sealants at any time during the experimental period （P〈0.001）. All the samples released similar amounts of P continuously during these 28 days. In conclusion, based on the type and the amount of ion release, BS is the best pit-and-fissure sealant among the four brands.

High-temperature glassy-ceramic sealants SiO_2-Al_2O_3-BaO-MgO and SiO_2-Al_2O_3-ZrO_2-CaO-Na_2O for solid oxide electrochemical devices

Glasses of the SiO_2-Al_2O_3-BaO-MgO and SiO_2-Al_2O_3-ZrO_2-CaO-Na_2O systems were synthesized in the perspective to apply them as sealants in SOFC at operating temperatures of 700-900 °C. Thermal properties of the chosen glass compositions and their compatibility with the SOFC materials(YSZ-electrolyte and alloy-interconnector Crofer22 APU, 15Х25Т) were investigated by means of synchronic thermal analysis and high-temperature dilatometry. The elemental analysis was performed by atomic emission spectroscopy. The average values of the temperature coefficients of the linear extension are 10.0×10^(-6) °С^(-1) for glass 45%SiO_2-15%Al_2O_3-25%BaO-15%MgO and 9.5×10^(-6) °С^(-1) for glass 60%SiO_2-10%Al_2O_3-10%ZrO_2-5%CaO-15%Na_2O. The gluing microstructure in YSZ/glass/Crofer22 APU was studied by scanning electron microscopy. The crystallization process of silicate phases was revealed to occur in the SiO_2-Al_2O_3-BaO-MgO glass. The analysis of the crystallization products was performed by Raman spectroscopy and X-ray diffraction. Glassy ceramics was proved to possess better parameters in comparison with amorphous glass to be used as a sealant in electrochemical sensors and oxygen sensors. The SiO_2-Al_2O_3-ZrO_2-CaO-Na_2O low-temperature amorphous glass can be applied in SOFC.

Bilayered Glass-Ceramics as Sealants for SOFCs

Glass-ceramics are often used as sealants in solid oxide fuel cells (SOFC). But interfacing components, such as ferritic stainless steel and YSZ electrolyte, may vary in their requirements regarding sealing properties, especially in terms of thermal expansion. A bilayered glass-ceramic system was developed to overcome the mismatch in coefficients of thermal expansion (CTE) between ferritic steel and YSZ. Therefore, two different glass-ceramics with slightly different CTEs were developed, one with good bonding characteristics to the ferritic steel and the other to the YSZ electrolyte. Steel and electrolyte components were coated with a layer of their corresponding glass sealant paste and heated up to form a sandwich sample. During the heat treatment of the sealing process, the glasses are crystallized into glass-ceramics. The resulting interface between the two glass-ceramics is of special interest. Cross-sections of the sandwich samples were cut, polished and investigated using SEM. The glass-ceramics show continuous, gap-free layers and excellent bonding to both steel and YSZ. Energy release rates are measured for single and bilayered glass sealants by mechanical testing. The designed bilayered glass-ceramics fulfill the special requirements of ferritic steel and YSZ. They show excellent potential to become a new outstanding sealant for SOFCs.

Buildings and civil engineering works-Sealants-Determination of changes in cohesion and appearance of elastic weatherproofing sealants after exposure of statically cured specimens to artificial weathering and mechanical cycling

Foreword ISO(the International Organization for Standardization)is a worldwide federation of national standards bodies(ISO member bodies).The work of preparing International Standards is normally carried out through ISO technical committees.Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee.

猪源纤维蛋白粘合剂在冠状动脉旁路移植术中的应用研究

目的评估猪源纤维蛋白粘合剂在冠状动脉旁路移植术(CABG)中的有效性、安全性以及经济性。方法回顾性分析2023年3—10月于首都医科大学附属北京安贞医院冠心病外科中心143例接受非停跳CABG患者的临床资料,其中67例患者术中使用了猪源纤维蛋白粘合剂(观察组),76例患者术中未使用(对照组)。分析2组重症监护病房(ICU)停留时间、术后引流量、引流管留置时间、术后住院时间、术后血液制品使用率、凝血功能及药物过敏发生情况。结果2组ICU停留时间、术后引流量、术后血液制品使用率比较差异均无统计学意义(均P>0.05)。观察组术后引流管留置时间以及住院时间均短于对照组[44(38,49)h比46(41,65)h、5(4,6)d比5(5,6)d](均P<0.05)。术前及术后第1天,2组凝血酶原活动度、活化部分凝血活酶时间、纤维蛋白原水平比较差异均无统计学意义(均P>0.05)。术后第1天,观察组纤维蛋白降解产物水平高于对照组(P<0.05)。2组均未发生药物相关过敏反应,住院费用比较差异无统计学意义(P>0.05)。结论CABG术中使用猪源纤维蛋白粘合剂具有良好的生物相容性,可缩短患者术后引流管留置时间及术后住院时长,但并不会减少术后引流量及输血率,对患者住院费用也无明显影响。

聚酰亚胺固化成型密封用有机硅密封剂的研制

通过耐高温抗氧化、抗密闭降解体系和催化剂体系研究,制备得到一种聚酰亚胺固化成型用有机硅密封剂,并对其密封性能进行了考核验证。研制得到的有机硅密封剂耐温等级可达380℃,在350℃×24h老化后仍具备一定弹性,具备优异的耐高温抗密闭降解性能。此外,该有机硅密封剂在高达380℃的聚酰亚胺固化温度下,3MPa的压力下,能够保证热压罐成型工艺所需的密封作用,满足聚酰亚胺复合材料的批量固化成型的需求。

欧标硅酮结构密封胶在太阳能光伏组件中的应用及可靠性

太阳能光伏发电行业的迅猛发展,推动了太阳能地面光伏组件用硅酮结构密封胶的广泛应用。本文分别从光伏组件用硅酮结构密封胶的应用特点、检测标准的先进性、检测方法与实际受力的符合性、耐长期人工老化的持久性、绿色环保型等方面,阐述了通过GB/T 29595—2023《地面用光伏组件密封材料硅橡胶密封剂》测试项目的硅酮结构密封胶,并再次满足欧洲标准ETAG002的技术要求时,在太阳能地面光伏组件中的应用更合理可靠。

混合填料不同配比对免垫片硅酮密封胶性能的影响

免垫片硅酮密封胶是一种可以用于要求高密封性的场合,如汽车、高铁、航天航空等领域的单组分室温硫化型密封胶。通过在密封胶中加入填料,可以提升密封胶的理化性能。以纳米碳酸钙和硅微粉作为填料,在填料总质量固定的情况下研究不同填料比例对免垫片硅酮橡胶性能的影响。试验发现,当纳米碳酸钙与硅微粉的质量比减小时,免垫片硅酮胶的表干速度、固化深度和耐高温性有所增加,而力学性能和对金属基材的粘接性能逐渐减弱。结合综合性能,纳米碳酸钙与硅微粉的质量比为5∶2时制备的免垫片硅酮密封胶具有更全面的理化性能。

Reduction of the closure time of postoperative enterocutaneous fistulas with fibrin sealant

AIM: To assess whether the use of fibrin sealantshortens the closure time of postoperative enterocutaneous fistulas (ECFs). METHODS: The prospective case-control study included 70 patients with postoperative ECFs with an output of < 500 mL/d, a fistulous tract of > 2 cm and without any local complication. They were divided into study (n = 23) and control groups (n = 47). Esophageal, gastric and colocutaneous fistulas were monitored under endoscopic visualization, which also allowed fibrin glue application directly through the external hole. Outcome variables included closure time, time to resume oral feeding and morbidity related to nutritional support. RESULTS: There were no differences in mean age, fistula output, and follow-up. Closure-time for all patients of the study group was 12.5 ± 14.2 d and 32.5 ± 17.9 d for the control group (P < 0.001), and morbidity related to nutritional support was 8.6% and 42.5%, respectively (P < 0.01). In patients with colonic fistulas, complete closure occurred 23.5 ± 19.5 d after the first application of fibrin glue, and spontaneous closure was observed after 36.2 ± 22.8 d in the control group (P = 0.36). Recurrences were observed in 2 patients because of residual disease. One patient of each group died during follow-up as a consequence of septic complications related to parenteral nutrition. CONCLUSION: Closure time was significantly reduced with the use of fibrin sealant, and oral feeding was resumed faster. We suggest the use of fibrin sealant for the management of stable enterocutaneous fistulas.

填料对硅烷改性聚醚密封胶性能的影响研究

探讨了填料在硅烷改性聚醚密封胶中的应用,重点分析了不同种类填料复配对密封胶力学性能和施工性能的影响。通过优化单一填料用量并进行复配试验,系统评估了各填料组合对密封胶整体性能的贡献。结果表明,合理选择填料及其配比能够显著改善密封胶的综合性能。

聚氨酯泡沫填缝剂制备优化及在高强复合路基中的应用

对高强复合路基耐久性优化过程中使用的单组分聚氨酯泡沫填缝剂进行制备和应用,解决高强复合路基耐久性不强的问题。按照配合比,将准备的材料进行预处理,按照不同的材料配比,制备单组分聚氨酯泡沫填缝剂,并放置24 h。根据某铁路工程路基的特性,制备高强复合路基试件,并对路基试件的耐久性能进行测试。将上述制备好的单组分聚氨酯泡沫填缝剂应用到制备的高强复合路基样本中,填缝完成后,将填缝好的试件进行养护,并对路基试件进行编号。利用马歇尔稳定度仪对填缝好的路基试件进行抗水渗测试,利用电子万能试验机对填缝好的路基试件进行抗弯拉强度测试,记录2次试验的测试结果。在抗水渗试验测试中,在60℃温度下,用水浸泡路基试件48 h后,A02路基试件的马歇尔稳定度最大,为14.5。在抗弯拉强度测试中,A02路基试件的抗弯拉强度数值最大,为562.36 MPa。结果显示:60%聚氨酯预聚体的单组分聚氨酯泡沫填缝剂能够实现对高强复合路基抗水渗性和抗弯拉强度的有效提高,实现对路基耐久性的优化。

Effect of implanting fibrin sealant with ropivacaine on pain after laparoscopic cholecystectomy

AIM:To investigate the safety and efficacy of implant-ing fibrin sealant with sustained-release ropivacaine in the gallbladder bed for pain after laparoscopic chole-cystectomy(LC).METHODS:Sixty patients(American Society of Anes-thesiologists physical status wasⅠorⅡand underwent LC)were randomly divided into three equal groups:group A(implantation of fibrin sealant in the gallbladder bed),group B(implantation of fibrin sealant carrying ropivacaine in the gallbladder bed),and group C(normal saline in the gallbladder bed).Postoperative pain was evaluated,and pain relief was assessed by visual analog scale(VAS)scoring.RESULTS:The findings showed that 81.7%of patients had visceral pain,50%experienced parietal,and 26.7% reported shoulder pain after LC.Visceral pain was significantly less in group B patients than in the other groups(P<0.05),and only one patient in this group experienced shoulder pain.The mean VAS score in group B patients was lower than that in the other groups.CONCLUSION:Visceral pain is prominent after LC and can be effectively controlled by implanting fibrin sealant combined with ropivacaine in the gallbladder bed.

Fibrin sealant for closure of mucosal penetration at the cardia during peroral endoscopic myotomy: A retrospective study at a single center

AIM To assess the efficacy and safety of fibrin sealant for closure of mucosal penetration at the cardia during peroral endoscopic myotomy(POEM).METHODS Twenty-four patients who underwent POEM and experienced mucosal injury of the cardia during the procedure were retrospectively identified. Of the 24 patients, 21 had mucosal penetration and 3 had only slight mucosal damage without penetration. The 21 patients with mucosal penetration received fibrin sealant for closure at the site of penetration. Penetration-related characteristics, treatment, and recovery were reviewed for all 21 patients to assess the efficacy and safety of fibrin sealant for closure of mucosal penetration at the cardia. Clinical data, including general characteristics, procedure-related parameters, Eckardt scores, lower esophageal sphincter pressures (LESP), and esophagogastroduodenoscopy(EGD) results, were analyzed to determine their influence on treatment success after mucosal penetration during POEM.RESULTS All 21 patients had a solitary mucosal penetration in the cardia (12 in esophageal region of the cardia, 9 in the stomach region of the cardia, and 1 in both the esophageal and stomach regions). Twelve had ahole-like penetration and 9 had a linear penetration. For those with a hole-like penetration, the mean size was 0.14 cm2 (0.02-0.32 cm2). For those with a linear penetration, the median size was 0.37 cm (0.10-1.00 cm). Closure of the mucosal penetration using fibrin sealant was performed successfully in all 21 patients(two patients required 5 m L fibrin sealant, and the remaining 19 patients required 2.5 mL). Two patients had a nasogastric tube placed for five days after POEM; the remaining 19 patients were kept fasting for 3 d. All 21 patients were discharged after a median of 5 d(range: 5-7 d) postoperatively. During a median 42 mo (range: 9-62 mo) follow-up, all 21 patients with a mucosal penetration successfully healed without the occurrence of infection, ulcer, or esophagitis. Furthermore, the median LESP decreased from 31.9 mm Hg (range: 21.9-67.1 mm Hg) preoperatively to 20.3 mm Hg (range: 6.0-41.0 mm Hg) postoperatively(P < 0.05). The median preoperative and postoperative Eckardt scores were 5.0(range; 4-10) and 1.0(range: 0-4), respectively (P < 0.05). Of the 21 patients with mucosal penetration, symptom remission, which is defined as a postoperative Eckardt score ≤ 3, was achieved in 20 patients(95.2%) indicating that mucosal penetration did not influence the success of POEM treatment if closed successfully using fibrin sealant.CONCLUSION Fibrin sealant is safe and effective for closure of mucosal penetration during POEM. Mucosal penetrations do not appear to influence the treatment success of POEM if closed successfully using fibrin sealant. Additional studies regarding the feasibility, efficacy, and safety of fibrin sealant for closure of larger mucosal penetrations is warranted.

Bioinspired Injectable Self-Healing Hydrogel Sealant with Fault-Tolerant and Repeated Thermo-Responsive Adhesion for Sutureless Post-Wound-Closure and Wound Healing

Hydrogels with multifunctionalities,including sufficient bonding strength,injectability and self-healing capacity,responsive-adhesive ability,fault-tolerant and repeated tissue adhesion,are urgently demanded for invasive wound closure and wound healing.Motivated by the adhesive mechanism of mussel and brown algae,bioinspired dynamic bonds cross-linked multifunctional hydrogel adhesive is designed based on sodium alginate(SA),gelatin(GT)and protocatechualdehyde,with ferric ions added,for sutureless post-wound-closure.The dynamic hydrogel cross-linked through Schiff base bond,catechol-Fe coordinate bond and the strong interaction between GT with temperature-dependent phase transition and SA,endows the resulting hydrogel with sufficient mechanical and adhesive strength for efficient wound closure,injectability and self-healing capacity,and repeated closure of reopened wounds.Moreover,the temperature-dependent adhesive properties endowed mispositioning hydrogel to be removed/repositioned,which is conducive for the fault-tolerant adhesion of the hydrogel adhesives during surgery.Besides,the hydrogels present good biocompatibility,near-infrared-assisted photothermal antibacterial activity,antioxidation and repeated thermo-responsive reversible adhesion and good hemostatic effect.The in vivo incision closure evaluation demonstrated their capability to promote the post-wound-closure and wound healing of the incisions,indicating that the developed reversible adhesive hydrogel dressing could serve as versatile tissue sealant.