拉伸速率对双向拉伸聚乙烯薄膜拉伸性能的影响

通过平膜法分步双向拉伸工艺制备具有不同纵向(MD)拉伸速率的双向拉伸聚乙烯(BOPE)薄膜。采用差示扫描量热仪、广角X射线衍射仪、透射雾影仪和电子拉力试验机对BOPE薄膜进行表征,同时利用双向拉伸实验设备上的拉伸力传感器记录BOPE薄膜在拉伸成型过程中的MD拉伸力。结果表明,当拉伸速率较慢或者较快时,BOPE薄膜中的分子链在MD方向没有取向或者取向较弱,仅在横向(TD)产生较强取向,此时BOPE薄膜的MD拉伸强度较低;而当拉伸速率适中时,BOPE薄膜不仅TD方向发生取向,而且在MD方向也具有一定程度的取向,此时BOPE薄膜沿着MD方向的拉伸强度较高。

高韧性无卤阻燃PC/ABS合金制备及其性能研究

研究了不同增韧体系以及不同组分丙烯腈-丁二烯-苯乙烯共聚物对阻燃聚碳酸酯(PC)/丙烯腈-丁二烯-苯乙烯共聚物(ABS)力学性能、阻燃性能与耐热性能的影响;制备的聚碳酸酯(PC)/丙烯腈-丁二烯-苯乙烯共聚物(ABS)复合材料的冲击性能可达到62.3 kJ/m^2,垂直燃烧可以达到V-0级。微观结构测试表明,阻燃剂在基材中的均匀分散是制备高韧性无卤阻燃PC/ABS合金的关键。

Key gene and protein changes in the beta-amyloid pathway following Longyanshen polysaccharides treatment in a mouse model of Alzheimer's disease

BACKGROUND： During onset and development of Alzheimer＇s disease, β-amyloid （Aβ） precursor protein （APP）, β-site amyloid precursor protein cleaving enzyme （BACE）, and β-amyloid are key genes and proteins in the Aβ pathway, and over-expression of these genes can lead to Aβ deposit/on in the brain. OBJECTIVE： To observe the influence of Longyanshen polysaccharides on expression of BACE, APP, and Aβ in the senescence-accelerated mouse prone/8 （SAMP8） brain, and to compare these effects with huperzine A treatment. DESIGN, TIME AND SETTING： A randomized, controlled, neurobiochemical experiment was performed at the Department of Pharmacology and Scientific Experimental Center of Guangxi Medical University from September 2005 to January 2008. MATERIALS： Longyanshen polysaccharfdes powder was extracted from the dried slices of the medicinal plant Longyanshen. The active component, Longyanshen polysaccharides, was provided by the Department of Pharmacology, Guangxi Medical University; huperzine A was purchased from Yuzhong Drug Manufactory, China. METHODS： Healthy SAMP8 mice were used to establish a model of Alzheimer＇s disease. A total of 50 SAMP8 mice were randomly assigned to 5 groups （n = 10）： SAMP8, huperzine A, low-, middle-, and high-dose polysaccharides. In addition, 10 senescence-accelerated mouse resistant 1 （SAMR1） mice were selected as normal controls. SAMP8 and SAMR1 mice were administered 30 mL/kg normal saline; the huperzine A group was administered 0.02 mg/kg huperzine A; the low-, middle-, and high-dose polysaccharides groups were respectively administered 45, 90, and 180 mg/kg Longyanshen polysaccharides. Each group was treated by intragastric administration, once per day, for 50 consecutive days. MAIN OUTCOME MEASURES： One hour after the final administration, immunohistochemical analysis was used to determine Aβ expression in the cortex and hippocampus of SAMP8 mice. Reverse-transcription polymerase chain reaction was used to determine mRNA levels of BACE and APP in SAMP8 brain tissue. RESULTS： Compared with the SAMR1 group, Aβ expression in the cerebral cortex and hippocampus, as well as expression of BACE, APP mRNA in the brain was significantly increased in the SAMP8 group （P 〈 0.05-0.01）. Compared with the SAMP8 group, Aβ expression, as well as BACE and APP mRNA expression, were significantly decreased in the cerebral cortex and hippocampus of huperzine A and low-, middle-, and high-dose polysaccharides groups （P 〈 0.05-0.01）. In particular, the effect of high-dose polysaccharides was the most significant （P 〈 0.05-0.01 ）. CONCLUSION： Longyanshen polysaccharides reduced or inhibited over-expression of BACE, APP, and Aβ in SAMP8 mice in a dose-dependent manner, and the effect was not worse than huperzine A.

Effects of Longyanshen polysaccharides on free radical metabolism in senescence accelerated-prone mice

BACKGROUND： Along with aging, antioxidase activity decreases and oxygen-derived free radicals greatly accumulate, resulting in cellular senescence, or even cell death. This is manifested by hypomnesia and disordered metabolism of free radicals. Studies have reported that Longyanshen polysaccharides have the function of antioxidation and improved brain memory. OBJECTIVE： To observe the effects of Longyanshen polysaccharides on free radical metabolism in brain tissue to verify the anti-aging mechanisms in senescence accelerated-prone （SAMP8） mice. DESIGN, TIME AND SETTING： The randomized, controlled, biochemical experiment was performed in the Department of Pharmacology and Scientific Experimental Center of Guangxi Medical University （China） from September 2005 to January 2008. MATERIALS： Forty SAMP8 mice were randomized into four groups： SAMP8 control group, as well as low-, mid-, and high-dose polysaccharide, with 10 mice in each group. Ten senescence accelerated-resistantprone （SAMR 1） mice served as the normal control group. Longyanshen polysaccharides, extracted from the medical plant Longyanshen, were supplied by the Department of Pharmacology, Guangxi Medical University Superoxide dismutase （SOD）, glutathione peroxidase （GSH-Px）, malonaldehyde （MDA）, nitric oxide （NO）, and total protein test kitwere purchased from Nanjing Jiancheng Bioengineering Institute （China）. METHODS： SAMP8 mice were used to establish a dementia animal model. SAMP8 and SAMR1 control mice were administered 30 mL/kg saline. The low-, middle-, and high-dose polysaccharide groups were administered 45, 90, and 180 mg/kg Longyanshen polysaccharides, respectively. Each group was treated by intragastric administration, once daily, for 50 continuous days. MAIN OUTCOME MEASURES： One hour after the last administration, mouse brain tissues were collected, and retro orbital blood sampling was performed. Spectrophotometry was used to measure SOD and GSH-Px activity, as well as MDA and NO concentration in sera and brains of SAMP8 mice. RESULTS： SOD and GSH-Px activity decreased significantly, and MDA and NO concentration increased significantly, in SAMP8 control group brain tissues, compared with the SAMP1 control group （P 〈 0.05）. Compared with the SAMP8 control group, Longyanshen polysaccharide-treated groups exhibited enhanced SOD and GSH-Px activity, as well as decreased MDA and NO concentration, in serum and brain tissue （P 〈 0.05）. Longyanshen polysaccharides exerted a similar effect on SOD, GSH-Px, MDA, and NO concentrations in serum and brain tissues of SAMP8 mice. CONCLUSION： Longyanshen polysaccharides scavenged free radicals effectively, reduced NO concentration and ameliorated NO toxicity, thereby influenced aging and stress, as well as improving memory capacity in the brain.

Clinical Study on Dark Tea with Pericarpium Citri Reticulatae Combined with Metformin for Type 2 Diabetes Mellitus

[Objectives]To observe the clinical effect of dark tea with pericarpium citri reticulateae combined with metformin for type 2 diabetes mellitus.[Methods]A total of 80 cases of patients with type 2 diabetes mellitus were randomly divided into the control group and the observation group with 40 cases in each group.The control group was given metform for treatment,and the observation group was given dark tea with pericarpium citri reticulateae combined with metformin for treatment.The two groups were continuously treated for 12 weeks.The indexes of patients were observed and recorded,such as the body mass index(BMI),abdominal circumference(AC),hemoglobin A1c(HbA1c),fasting blood glucose(FBG),postprandial 2 h blood glucose(P2hBG),uric acid(UA),total cholesterol(TC),and triglyceride(TG).The incidence of adverse reactions during the treatment period and the patient satisfaction for treatment in the two groups were counted.[Results]After treatment,the FBG,P2hBG and HbA1c in the two groups were decreased when compared with those before treatment(P<0.05)and the decrease of the above indexes in the observation group was more significant than that in the control group(P<0.05).After treatment,the BMI,AC,UA,TC and TG in the observation group were decreased more significantly when compared with those before treatment and those in the control group after treatment,differences were statistically significant(P<0.05).The above indexes in the control group did not change significantly before and after treatment(P>0.05).The incidence of adverse reactions was 2.5%in the observation group and 5.0%in the control group,the difference was not statistically significant(P>0.05).The patient satisfaction was 97.5%in the observation group and 55.0%in the control group,the difference was significant(P<0.05).[Conclusions]The curative effect of dark tea with pericarpium citri reticulateae combined with metformin for type 2 diabetes mellitus is better than that of western medicine alone and has no obvious adverse reactions,thus it is worthy of clinical promotion and application.

Empirical Analysis of the Typical Breeding Pattern of Clam in Hongdao Town and the Preliminary Estimates of Costs and Benefits

Based on the survey data about clam breeding farmers in Hongdao Town in August 2011,this paper analyzes the production and operation of typical clam breeding pattern,and estimates the costs and benefits. Through the analysis of operation conditions and economic conditions of Hongdao clam breeding,this paper aims to explore a more reasonable and effective breeding pattern so as to reduce breeding costs and market risks,and increase breeding farmers' income.

Preliminary Breeding of Superior Maize Combinations in Zhaotong,Yunnan

[Objectives]This study was conducted to select superior maize combinations.[Methods]With the control maize variety Haihe 2 in the middle altitude area of Yunnan Province as the control,adopting a single-factor randomized block three-replicate experiment design,a one-year field cultivation experiment was carried out in Luyin Village,Yongfeng Town,Zhaoyang District,Zhaotong City.[Results]A total of 11 new superior maize combinations including ZT-1 and ZT-2 were obtained.Through comprehensive comparison analysis with Haihe 2(CK),we selected six superior combinations of ZT-1,ZT-3,ZT-4,ZT-6,ZT-7 and ZT-9,which showed overall performance better than the control Haihe 2(CK)in terms of resistance,yield,and ear traits.[Conclusions]The selected 6 superior combinations have promotion value,and are recommended for higher-level trials and demonstrations.

Microwave-Assisted Modification of Carbon Nanotubes with Biocompatible Polylactic Acid

Polylactic acid (PLA) was successfully covalently grafted onto multi-walled carbon nanotubes (MWCNT) by microwave-assisted polymerization of lactide monomers. The final products MWCNT-g-PLA were characterized with Fourier-transform IR (FTIR), Raman spectroscopy, thermogravimetric analyses (TGA) and transmission electron microscopy (TEM). The results indicated PLA chain was covalently attached to the MWCNT. The grafted PLA was uniformly coated on the surface of MWCNT with a layer thickness of 2 ~ 6 nm. The grafted PLA content could be controlled by microwave irradiation time and the concentrations of reactant. The product with 60.5% grafted PLA content can be synthesized in one hour.

Electrical Conductivity and Crystallization of Polylactic Acid Nanocomposites Containing Surfactant Modified Carbon Nanotubes

In order to extend the usage of PLA-based nanocomposites, the modification of multi-walled carbon nanotubes (MWCNT) and preparation of surfactant modified carbon nanotubes (SMCNT) involved PLA nanocomposites (PLA/SMCNT) were investigated. The morphologies, electrical properties and crystallization behavior of PLA/SMCNT composites were investigated. The TEM images indicated that SMCNTs were dispersed homogenously in the PLA matrix without forming aggregates. The electrical conductivity of PLA/SMCNT was greatly improved and the percolation threshold of PLA/SMCNT was calculated to be 0.61% which is much lower than 1.45% of PLA/MWCNT composite. The crystallization behavior suggested that SDBS together with MWCNT acted as heterogeneous nucleating agent and accelerated the nucleation. Meanwhile, the SMCNT also devoted further restrained effect to spherulites growth due to its well dispersion and improved compatibility with matrix.

The effect of ergosterol on the allogrooming behavior of termites in response to the entomopathogenic fungus Metarhiziumanisopliae

Termites have physiological and behavioral immunities that make them highly resistant to pathogen infections,which complicates biocontrol efforts.However,the stimuli that trigger the pathogen-avoidance behaviors of termites are still unclear.Our study shows that workers of Coptotermes formosanus exposed to the conidia of Metarhizium anisopliae exhibited a significantly higher frequency and longer duration of allogrooming behaviors compared with untreated termites.Volatile compounds in the cuticle of control termites and termites previously exposed to a suspension of M.anisopliae conidia were analyzed and compared using a gas chromatography-mass spectrometer(GC-MS).Our results showed that the amount of ergosterol differed between the fungus-exposed and control termites.Choice tests showed that termites significantly preferred to stay on filter paper treated with ergosterol(0.05,0.1,or 1.0 mg/mL)compared with control filter paper.In addition,termites exposed to ergosterol followed by M.anisopliae conidia were allogroomed at a significantly higher frequency and for a longer duration than termites exposed to alcohol(the solvent used with the ergosterol in the ergosterol trials)alone followed by M.anisopliae conidia.These results showed that ergosterol may enhance the allogrooming behavior of termites in the presence of entomopathogenic fungi.

Preparation of carbon nanotube films towards mechanical and electrochemical energy storage

Due to unique and excellent properties,carbon nanotubes(CNTs)are expected to become the next-generation critical engineering mechanical and energy storage materials,which will play a key role as building blocks in aerospace,military equipment,communication sensing,and other cutting-edge fields.For practical application,the assembled macrostructures from individual CNTs are the common paradigms such as fibers or films.As the main representative,CNT films can not only retain the unique properties of their CNTs components,but also are more likely for mass-production than other macrostructures.Therefore,in this review,we focus on preparation of CNT films and discuss their emerging applications in the field of mechanical and electrochemical energy storage/conversion.Firstly,different preparation processes are systematically summarized.Then we introduce some typical strategies to improve their mechanical performances besides strengthening mechanism.Based on the progress of mass-production and performance optimization,we further discuss their potential utilization in mechanical and electrochemical energy storage/conversion devices.Finally,future perspectives for the development of CNT films in both production and application are proposed.We hope that this review will shed light on the preparation/assembly of CNT films and integrated application of excellent properties from individual to macroscopic dimensions.Moreover,the preparation and cross-scale application paradigms of CNT films also offer a good model for other macroscopic ordered assemblies of one-dimensional nanomaterials.

Jianpijiedu Fang improves survival of hepatocarcinoma mice by affecting phosphatase and tensin homolog, phosphoinositide 3-kinase, and focal adhesion kinase

OBJECTIVE: To investigate the effect of Jianpijiedu Fang (JPJDF) on phosphatase and tensin homolog (PTEN), phosphoinositide 3-kinase (PI3K), and focal adhesion kinase (FAK), and on the survival of hepatocellular carcinoma (HCC) nude mice. METHODS: Forty male nude mice were randomly divided into 4 groups. Human HCC tissue was implanted in the livers of three groups. After 24 h, the three groups were treated respectively with JPJDF (37.5 g/kg), saline (20 mL/kg) and Tegafur (FT-207, 160 mg/kg) once a day for 10 weeks. The control group without implanting the tissue was concurrently treated with saline (20 mL/kg). The survival data and body weight of all mice were recorded, and expression levels of PTEN, PI3K and FAK in normal tissue and cancer tissue of the livers were eval-uated with immunohistochemical method. RESULTS: The cumulative survival rate of the mice in the JPJDF group was higher than those of the other groups. The rate of weight loss was the lowest in JPJDF group. The survivability and weight loss rate in FT-207 group were the poorest in all groups. The expression intensity of PTEN was higher in normal tissues than in cancer tissues, and lower in the normal tissues of HCC models than in that of mice without HCC. The PTEN expression intensity in normal tissue and cancer tissue from mice treated with FT-207 were lower than that from the mice treated with JPJDF or saline.The expression intensity of PI3K was higher in cancer tissue than in normal tissue. The PI3K expression intensity was the lowest in normal tissue and cancer tissue from mice treated with JPJDF, and the intensity from mice treated with FT-207 was the highest. In mice treated with JPJDF, the expression intensity of FAK was higher in the normal tissue and lower in the cancer tissue than those of the other treatment groups. CONCLUSION: The mechanism accounting for the prolonged survival of HCC-bearing mice treated with JPJDF might be related to the reduction in weight loss and the benign regulation of PTEN, PI3K, and FAK.

Synergetic delivery of triptolide and Ce6 with light-activatable liposomes for efficient hepatocellular carcinoma therapy

Hepatocellular carcinoma(HCC)has been known as the second common leading cancer worldwide,as it responds poorly to both chemotherapy and medication.Triptolide(TP),a diterpenoid triepoxide,is a promising treatment agent for its effective anticancer effect on multiple cancers including HCC.However,its clinical application has been limited owing to its severe systemic toxicities,low solubility,and fast elimination in the body.Therefore,to overcome the above obstacles,photo-activatable liposomes(LP)integrated with both photosensitizer Ce6 and chemotherapeutic drug TP(TP/Ce6-LP)was designed in the pursuit of controlled drug release and synergetic photodynamic therapy in HCC therapy.The TP encapsulated in liposomes accumulated to the tumor site due to the enhanced permeability and retention(EPR)effect.Under laser irradiation,the photosensitizer Ce6 generated reactive oxygen species(ROS)and further oxidized the unsaturated phospholipids.In this way,the liposomes were destroyed to release TP.TP/Ce6-LP with NIR laser irradiation(TP/Ce6-LP+L)showed the best antitumor effect both in vitro and in vivo on a patient derived tumor xenograft of HCC(PDXHCC).TP/Ce6-LP significantly reduced the side effects of TP.Furthermore,TP/Ce6-LP+L induced apoptosis through a caspase-3/PARP signaling pathway.Overall,TP/Ce6-LP+L is a novel potential treatment option in halting HCC progression with attenuated toxicity.

Effect of polypeptide 2B1 on condition of dampness pattern in rats in terms of Traditional Chinese Medicine

OBJECTIVE: This study investigated how polypeptide 2B1 is involved in regulating and governing dampness in rat models with dampness pattern defined in terms ofTraditional Chinese Medicine.METHODS: We randomly divided 48 SPF10-week-old male Sprague-Dawley(SD) rats into a normal group, normal + Aristolochic acid I(AA-I) for5 min group, normal + AA-I for 60 min group,dampness pattern group(DS-Group), dampness pattern + AA-I for 5 min group, and dampness pattern + AA-I for 60 min group. Groups were then treated accordingly. We took out the lung, stomach, liver, spleen, kidney, large intestine, and small intestine tissues to detect gene and protein expression of organic anion transporter polypeptide 2B1(OATP2B1).RESULTS: Gene expression of OATP2B1 in spleen,kidney, and small intestine of rats with dampness pattern was lower than that in normal rats(P<0.05).The gene expressions of OATP2B1 in liver, stomach,large intestine, and small intestine were lower than that in control rats at different time points after being stimulated by AA-I(P<0.05).CONCLUSION: There is coordination among multiple viscera in handling the condition of dampness,and the mechanism underlying the action may rely on regulating the expression of OATP2B1.

Correlation between pathogenesis of dampness syndrome and Interleukin-2,Interleukin-8 in rats

OBJECTIVE: To explore the pathogenesis of dampness syndrome by detecting the changes of interleukin-2 (IL-2) and interleukin-8 (IL-8) levels. METHODS: Female Sprague Dawley rats were divided randomly into five groups according to the random number table: a normal group (GroupⅠ), an external dampness group (GroupⅡ), an internal dampness group (Group Ⅲ), and an external and internal dampness group (GroupⅣ). Twenty days after the model made, IL-2 and IL-8 levels were detected by radioimmunoassay method. RESULTS: The IL-2 and IL-8 levels among groups were significant (F=3.102, P<0.05; F=2.657, P<0.05, respectively). The level of IL-2 in Group Ⅱ and Group Ⅲ were higher than that in GroupⅠ(P<0.05, P<0.01, respectively), especially higher in the Group Ⅲ compared with GroupⅡ (P<0.05). The lev- el of IL-8 in Group Ⅲ were higher than those inGroupⅠ, GroupⅡ and GroupⅣ (P<0.05, P<0.01, P< 0.05, respectively). In the GroupⅢ, the 24-hour wa ter and body weight were higher than that in the GroupⅣ (all P<0.05), and spontaneous movemen frequency was higher than those in GroupⅡ and GroupⅣ (P<0.05). CONCLUSION: Immune activation and inflammato ry reaction might be easily caused by externa danpness other than internal dampness.