Synergistic effect of novel ionic liquid/graphene complex on the flame retardancy of epoxy nanocomposites

Zhang Chunhong,Xu Zice,Sui Wenbo,Zang Junbo,Ao Yuhui,Wang Lu,Shang Lei 한국탄소학회 2023 Carbon Letters Vol.33 No.2

Epoxy resin (EP) is a thermosetting resin with excellent properties, but its application is limited due to its high brittleness and poor flame retardancy. Therefore, to solve this problem, a dispersion system of imidazole-containing ionic liquid ([Dmim]Es) and graphene in epoxy resin is designed based on the π–π stacking effect between imidazole and graphite layers. The study on the thermal and flame-retardant properties of the composites show that the modified [Dmim]Es–graphene nanosheets improved the flame retardancy, smoke suppression and thermal stability of epoxy resin. With the addition of 5wt% [Dmim]Es and 1% Gra, the exothermic rate (HRR) and total exothermic (THR) of the composites decrease by 35% and 30.2% compared with the untreated epoxy cross-linking, respectively. The limiting oxygen index reaches 33.4%, the UL-94 test rating reaches V-0. The characterization of mechanical properties shows that the tensile properties and impact properties increased by 13% and 30%, respectively. Through SEM observation, the addition of [Dmim]Es improves the dispersion of graphene in the EP collective and changes the mechanical fracture behavior. The results show that ionic liquid [Dmim]Es-modified graphene nanosheets are well dispersed in the matrix, which not only improves the mechanical properties of epoxy resin (EP), but also has a synergistic effect on flame retardancy. This work provides novel flame-retardant and graphene dispersion methods that broaden the range of applications of epoxy resins.

The Changes of Proteomes Components of Helicobacter pylori in Response to Acid Stress without Urea

Chunhong Shao,Qunye Zhang,Wei Tang,Wei Qu,Yabin Zhou,Yundong Sun,Han Yu,Jihui Jia 한국미생물학회 2008 The journal of microbiology Vol.46 No.3

Acid stress is the most obvious challenge Helicobacter pylori encounters in human stomach. The urease system is the basic process used to maintain periplasmic and cytoplasmic pH near neutrality when H. pylori is exposed to acidic condition. However, since the urea concentration in gastric juice is approximately 1 mM, considered possibly insufficient to ensure the survival of H. pylori, it is postulated that additional mechanisms of pH homeostasis may contribute to the acid adaptation in H. pylori. In order to identify the acid-related proteins other than the urease system we have compared the proteome profiles of H. pylori strain 26695 exposed to different levels of external pH (7.4, 6.0, 5.0, 4.0, 3.0, and 2.0) for 30 min in the absence of urea using 2-DE. Differentially expressed proteins were identified by MALDI-TOF-TOF-MS analysis, which turned out to be 36 different proteins. The functions of these proteins included ammonia production, molecular chaperones, energy metabolism, cell envelope, response regulator and some proteins with unknown function. SOM analysis indicated that H. pylori responds to acid stress through multi-mechanisms involving many proteins, which depend on the levels of acidity the cells encounter.

Effect on Viability of Microencapsulated Lactobacillus rhamnosus with the Whey Proteinpullulan Gels in Simulated Gastrointestinal Conditions and Properties of Gels

Minghao Zhang,Dan Cai,Qiumei Song,Yu Wang,Haiyue Sun,Chunhong Piao,Hansong Yu,Junmei Liu,Jingsheng Liu,Yuhua Wang 한국축산식품학회 2019 한국축산식품학회지 Vol.39 No.3

Lactobacillus rhamnosus GG (LGG) has low resistance to low pH and bile salt in the gastrointestinal juice. In this study, the gel made from whey protein concentrate (WPC) and pullulan (PUL) was used as the wall material to prepare the microencapsulation for LGG protection. The gelation process was optimized and the properties of gel were also determined. The results showed the optimal gel was made from 10% WPC and 8.0% PUL at pH 7.5, which could get the best protective effect; the viable counts of LGG were 6.61 Log CFU/g after exposure to simulated gastric juice (SGJ) and 9.40 Log CFU/g to simulated intestinal juice (SIJ) for 4 h. Sodium dodecyl sulphite polyacrylamide gel electrophoresis (SDS-PAGE) confirmed that the WPC-PUL gel had low solubility in SGJ, but dissolved well in SIJ, which suggested that the gel can protect LGG under SGJ condition and release probiotics in the SIJ. Moreover, when the gel has highest hardness and water-holding capacity, the viable counts of LGG were not the best, suggesting the relationship between the protection and the properties of the gel was non-linear.

Effects of Antiepileptic Drugs on the Carotid Artery Intima-Media Thickness in Epileptic Patients

Qilun Lai,Chunhong Shen,Yang Zheng,Yinxi Zhang,Yi Guo,Meiping Ding 대한신경과학회 2017 Journal of Clinical Neurology Vol.13 No.4

Background and Purpose It has been reported that taking antiepileptic drugs (AEDs) may increase the risk of atherosclerosis. We performed a meta-analysis to evaluate the carotid artery intima-media thickness (CA-IMT) as a surrogate factor for atherosclerosis in epileptic patients. Methods We searched NCBI (PubMed), ISI Web of Knowledge, EMBASE, and the Cochrane Library databases for studies of the association between AEDs and CA-IMT in epileptic patients. A random-effects meta-analysis was used to pool results across studies. Results Fifteen studies involving 1,775 epileptic patients were included in the analysis. The overall CA-IMT was significantly larger among users of AEDs [mean difference (MD)=0.09 mm, 95% confidence interval (CI)=0.06–0.12 mm). When stratified by age, the MD was similar in adult patients (MD=0.09 mm, 95% CI=0.06–0.13 mm), but no significant difference was observed in children (MD=0.03 mm, 95% CI=0.00–0.07 mm). Regarding specific AEDs, monotherapy with carbamazepine (CBZ) or valproic acid (VPA) was associated with a larger CA-IMT, while phenytoin monotherapy was not and the result for lamotrigine was inconclusive. Conclusions This study suggests that using AEDs is associated with the CA-IMT in patients with epilepsy, particularly for adult patients. In particular, CBZ and VPA may be related to a significant increase in CA-IMT.

Helicobacter pylori Proteins Response to Nitric Oxide Stress

Wei Qu,Yabin Zhou,Chunhong Shao,Yundong Sun,Qunye Zhang,Chunyan Chen,Jihui Jia 한국미생물학회 2009 The journal of microbiology Vol.47 No.4

Helicobacter pylori is a highly pathogenic microorganism with various strategies to evade human immune responses. Nitric oxide (NO) and reactive nitrogen species (RNS) generated via nitric oxide synthase pathway are important effectors during the innate immune response. However, the mechanisms of H. pylori to survive the nitrosative stress are not clear. Here the proteomic approach has been used to define the adaptive response of H. pylori to nitrosative stress. Proteomic analysis showed that 38 protein spots were regulated by NO donor, sodium nitroprusside (SNP). These proteins were involved in protein processing, antioxidation, general stress response, and virulence, as well as some unknown functions. Particularly, some of them were participated in iron metabolism, potentially under the control of ferric uptake regulator (Fur). Real time PCR revealed that fur was induced under nitrosative stress, consistent with our deduction. One stress-related protein up-regulated under nitrosative conditions was thioredoxin reductase (TrxR). Inactivation of fur or trxR can lead to increased susceptivity to nitrosative stress respectively. These studies described the adaptive response of H. pylori to nitric oxide stress, and analyzed the relevant role of Fur regulon and TrxR in nitrosative stress management.

An improved unified description of charge-carrier mobilities in disordered organic semiconductors

Liguo Wang,Huaiwu Zhang,Xiaoli Tang,Chunhong Mu,Jun Li 한국물리학회 2010 Current Applied Physics Vol.10 No.4

An improved unified description of the dependence of the charge-carrier mobility on temperature, carrier density, and electric field in disordered organic semiconductors is proposed based on the Arrhenius temperature dependence ln(μ) ∝ / 1=T and non-Arrhenius temperature dependence ln(μ) ∝ / 1=T2. The improved description of the mobility can quite well fit the numerical solution of the master equation at both the low densities and high densities, the latter of which cannot be accurately described using the model introduced by Pasveer et al. [6]. Experimental current–voltage characteristics in devices based on organic semiconductors are also excellently reproduced with this improved description. Finally, we calculate and analyze the distribution of the charge-carrier density and electric field with position in polymer layer for two organic semiconductors in detail by using the improved description.