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21.

In this study, exposure experiments were conducted to assess the effects of polystyrene nanoparticles (PS) and amine-modified polystyrene nanoparticles (APS) at environmental concentrations (1, 10, and 100 µg L??1) on two fungal species (Geotrichum candidum and Aspergillus niger), isolated from leaf litter in streams, concerning their growth and metabolic activity. Results showed that PS at 1 and 10 µg L??1 have hormesis effects on G. candidum growth. Compared with G. candidum, A. niger had higher sensitivity to nanoplastic exposure. Besides, the peroxidase and cellobiohydrolase activities of A. niger were significantly inhibited by nanoplastics (except 1 µg L??1 PS), which would weaken its metabolic activity in carbon cycling. These results provided a new thought on how the growth and functions of aquatic fungi cope with the stress induced by nanoplastics. Overall, the study provided evidence for the different responses of aquatic fungi to nanoplastics in streams.

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22.
明确了公路费用分摊的概念,指出了它在道路使用者税费制定过程中的地位与作用;阐述了费用分摊的两大基本目标--效率与公平,并据此对国外公路费用分摊方法进行了分类,提出了公路费用分摊研究的基本框架;介绍了每种分摊方法的基本内容,并着重分析了它们的优缺点.  相似文献   
23.
夏玉凤  王强  濮祖茂 《中药材》2003,26(5):323-326
分别采用扫描电镜和紫外光谱法对地肤子、藜、小藜和扫帚菜四种药材进行了比较鉴别。结果表明:扫描电镜下四种药材的胞果、毛茸、气孔和种子形态特征有较为明显的区别;紫外光谱扫描结果表明地肤子和扫帚菜无明显区别,但与藜和小藜之间有显著区别。  相似文献   
24.
Over the last decade kidney transplantation has become a common therapeutic procedure for patients with end-stage renal diseases. Between 1988 and 1998 donors rate per million population has dramatically increased in our environment, thus providing us with more chances to offer kidney transplantation to a larger number of patients. The technico-surgical difficulties that have to be faced however, are increasingly frequent and require a search for new approaches and innovative changes to the usual surgical techniques for our patient's benefit.  相似文献   
25.
我国鼻外科的现状及存在的问题   总被引:4,自引:0,他引:4  
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26.
OBJECTIVE: To compare the effectiveness of three new topical anesthetics that do not contain cocaine (prilocaine-phenylephrine, tetracaine-phenylephrine [tetraphen], and tetracaine-lidocaine-phenylephrine) to that of tetracaine-adrenaline-cocaine (TAC) during laceration repair in children. DESIGN: Prospective, randomized, double-blind clinical trial. SETTING: The emergency department of an urban children's hospital. PARTICIPANTS: Children 1 year of age or older with a laceration /= 5 years of age using a visual analogue scale (VAS). Suture technicians, research assistants, and parents also scored pain using a seven-point Likert scale. In addition, suture technicians completed an anesthetic effectiveness scale. RESULTS: There was consistently no difference demonstrated between the effectiveness of tetraphen and that of TAC for each outcome measure of each observer group. A statistically significant difference was seen among anesthetics when comparing VAS and Likert scale scores of suture technicians and Likert scale scores of research assistants. Based on post hoc analyses, these statistically significant differences were between TAC and prilocaine-phenylephrine (suture technician VAS and Likert scale) and between TAC and tetracaine-lidocaine-phenyl-ephrine (suture technician Likert scale), but not between TAC and tetraphen. When power analyses were performed using alpha = 0.05 and beta = 0.20, it was possible to detect a difference of 1.2 VAS units for each of the observer groups. Based on anesthetic effectiveness scale scores, the three new topical preparations collectively performed significantly better on the face and scalp than on the extremities (relative risk = 1.83; 95% confidence interval 1.20 < relative risk < 2.79). CONCLUSION: This study demonstrated the effectiveness and safety of three new non-cocaine-containing topical anesthetics. Consistently, there was no statistical difference demonstrated between the effectiveness of tetraphen and that of TAC for each outcome measure of each observer group. Tetraphen offers an effective alternative to TAC during laceration repair in children.  相似文献   
27.
Increased placental apoptosis in intrauterine growth restriction   总被引:2,自引:0,他引:2  
OBJECTIVES: Our purpose was to investigate a possible role for apoptosis in the pathophysiologic mechanisms of intrauterine growth restriction. STUDY DESIGN: Placental samples were obtained from 43 uncomplicated third-trimester pregnancies and from 26 pregnancies complicated by intrauterine growth restriction. The definition used to identify cases of intrauterine growth restriction depended on three criteria: clinical evidence of suboptimal growth, ultrasonographic evidence of deviation from an appropriate growth percentile, and individualized birth weight ratios <10th percentile. Light microscopy was used to quantify the incidence of apoptosis. Electron microscopy and TUNEL (terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick end labeling) staining were used to confirm the occurrence of apoptosis. RESULTS: Quantification of apoptosis (medians and interquartile ranges) resulted in the following values: normal third trimester (n = 43) 0.14% of cells (0.08% to 0.20%) and intrauterine growth restriction third trimester (n  = 26) 0.24% of cells (0.16% to 0.29%). The incidence of apoptosis was significantly higher in placentas from pregnancies with intrauterine growth restriction compared with normal third-trimester placentas (p < 0.01, Mann Whitney U test). CONCLUSIONS: These results suggest that apoptosis may play a role in the pathophysiologic mechanisms of intrauterine growth restriction.(Am J Obstet Gynecol 1997;177:401)  相似文献   
28.
29.
目的应用前庭诱发的肌源性电位(vestibular evoked myogenic potentials,VEMPs),观察Tullio现象与Ramsay Hunt综合征的电位特点,为诊断提供客观依据.方法Tullio现象与Ramsay Hunt综合征各1例,通过已经建立的VEMPs检查方法观察两者的电位引出情况.结果正常人VEMP刺激声在阈上85dB nHL可引出VEMPs.本文Tullio现象患者在刺激强度降至39dB nHL时仍可引出.而健侧在69dB nHL时就已不能引出.Ramsay Hunt综合征在阈上105dBHL右侧不能引出VEMP;而左侧可以引出.结论VEMPs可用来了解前庭下神经的功能状态.由于VEMPs的检查特点,可用于动态观察前庭神经病变后的恢复情况.  相似文献   
30.
为了了解资中县HIV/AIDS纳入新型合作医疗所产生的影响,分析该渠道筹集并解决艾滋病医药费用的可行性。结果发现,HIV/AIDS纳入新型合作医疗一定程度上可以有效分担艾滋病医药费用,但若感染者人数超过合作医疗所能覆盖的临界范围,则需开启政府分担功能,设立艾滋病专项基金用于补偿合作医疗无法覆盖的部分。  相似文献   
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