湖北巨猿牙齿化石龋病观察

本文共调查了267枚从鄂西山区收集的巨猿牙齿化石现发生情况,发现其中有52枚（占19.5%)的颊齿有程度不同的龋蚀现象,其患龋率显著高于古人类,同时也高于广西巨猿的患龋率。巨猿牙齿的这种高频率龋蚀现象,除牙齿结构因素外,可能与该物种食性的狭窄化和营养贫乏导致牙齿不良钙化有关,是伴随巨猿体型的巨型化而趋向该物种衰退和绝灭的病理表征之一。     

新型绿色阻垢剂γ-聚谷氨酸的阻垢性能

以实验室自制的低相对分子质量γ-聚谷氨酸(LMPGA)为研究对象,系统研究其阻碳酸钙垢、硫酸钙垢性能及其相关影响因素。结果表明:LMPGA的平均相对分子质量在5.0×103和7.0×103时,具有相近的阻碳酸钙垢性能,且在药剂投加质量浓度达到20 mg/L时,阻垢率可达88%左右;随着Ca2+浓度、pH值、恒温温度及恒温时间的增加,其阻碳酸钙垢性能发生下降;LMPGA是一种优良的硫酸钙阻垢剂,在药剂投加质量浓度达10 mg/L时,其硫酸钙阻垢率可达90%以上。     

降雨能量对东北典型黑土区土壤溅蚀的影响

溅蚀特征研究可揭示溅蚀发生机理,而现有研究大多用溅蚀量来表征溅蚀特征,不能全面准确地反应溅蚀作用过程。为此,基于改进的试验土槽进行室内模拟降雨试验,研究降雨能量对坡面不同方向溅蚀量及溅蚀过程的影响。试验设计包括2种降雨强度(50 mm/h和100 mm/h)和10个降雨能量,其中10个降雨能量是通过2种降雨强度(50 mm/h和100 mm/h)和5个雨滴降落高度(3.5,5.5,7.5,9.5、11.5 m)来实现的。结果表明:在相同降雨强度下,坡面总溅蚀分量均随降雨能量的增加而增大。次降雨坡面溅蚀量均为向下坡最大,其次为侧坡溅蚀量,而向上坡溅蚀量最小。当降雨强度由50mm/h增加至100mm/h时,坡面向上坡溅蚀量增加2.3—5.0倍,向下坡溅蚀量增加1.7—5.1倍,侧坡溅蚀量增加1.9—4.3倍,总溅蚀量增加1.9—4.5倍,净溅蚀量增加1.2—6.4倍。对于不同降雨能量处理,坡面溅蚀率均表现为坡面产流前随降雨历时的增加而递增,产流后迅速达到峰值,之后逐渐减小并趋于稳定。定量分析了各溅蚀分量、总溅蚀量、净溅蚀量与降雨能量的关系,提出了溅蚀发生的降雨能量阈值,发现雨滴溅蚀发生的临界能量为3—6 J m~(-2)mm~(-1),且向上坡溅蚀量,向下坡溅蚀量,净溅蚀量和总溅蚀量皆与降雨能量呈幂函数关系,而侧坡溅蚀量与降雨能量呈二次多项式关系。     

大肠杆菌O157显色培养基检测效果的评价

【目的】评价显色培养基对大肠杆菌O157:H7(Escherichia coli O157:H7)的检测效果。【方法】本实验室研制的大肠杆菌O157显色培养基(HKM),与国外梅理埃、科玛嘉及国内厂家的同类产品及传统培养基CT-SMAC作比较,对相关菌株以及污染样品和实际样品进行对比测试。【结果】实验室研制的HKM大肠杆菌O157显色培养基与科玛嘉同类产品在特异性、灵敏度及检测效果方面均无明显差异,均优于梅里埃、国内厂家产品及CT-SMAC。【结论】HKM大肠杆菌O157显色培养基具有高检出率及高特异性的特点,具有较好的应用价值和前景。     

不同施肥制度下潮棕壤钾素肥力变化和土壤缺钾指标

通过在潮棕壤上进行的15年定位试验研究了不同施肥制度下钾素肥力变化和土壤缺钾指标.结果表明:不施钾肥处理加剧了土壤钾素的消耗,土壤速效钾和缓效钾浓度均有不同程度的下降;单施钾肥处理不能维持土壤钾素平衡,土壤中速效钾和缓效钾浓度仍有下降趋势;循环堆肥处理可在一定程度上补偿土壤钾的支出,但需配施钾肥;循环堆肥和钾肥配施处理土壤速效钾和缓效钾浓度基本保持不变.根据历年试验结果进行统计分析表明,用十字交叉法得出的玉米和大豆土壤速效钾临界值均为73mg.kg-1.     

用猫豆渣为原料制备口服水解蛋白

本文介绍从提取左旋多巴后的废渣——猫豆[Mueuna Cochinchinenris(Lour) A.Cheual]渣为原料制备口服水解蛋白。首先从豆渣中提取酪蛋白,再经酸水解法而制备。工艺设计考虑到原料的特点,排除了残存的左旋多巴,收得率为豆渣的11～13％。成品经氨基酸分析仪测定,证明含有七种必需氨基酸在内的十七种氨基酸,氨基氮的含量较国内同类产品高。各种必需氨基酸的配比,接近人乳模式。经测定小白鼠经口LD_(50)及95％可信限范围为27.8(25.4～30.2)g/kg。在亚急性毒性试验中未发现任何不良反应。     

壳聚糖接枝胍乙酸缓蚀剂的研究

本文以1氯-胍乙酸和自制壳聚糖为原料,合成了一种良好的酸洗缓蚀剂-胍乙酸壳聚糖。以失重法研究了其对N80碳钢的缓蚀性能,并以交流阻抗谱研究了其在N80钢表面的吸附行为,得出缓蚀剂分子在N80钢表面吸附满足Langmu ir模式,同时算出了其吸附热。本文还采用色谱-质谱联用仪研究了缓蚀剂在酸中的降解规律,分析了其较长时间维持较高缓蚀作用的机理。     

生物防治因子

<正> 水生霉菌雕蚀菌是蚊子幼虫的寄生物。研究了该菌作为生防因子的可能性。骚蚊雕蚀菌的减数分裂在抗逆抱子囊中发生,这证实这种假设,即这个寄生物的双倍期仅在蚊子体内出现,其单倍期存在于挠足纲体内。     

耳唇槽舌兰——中国兰科一新种

对产于云南的兰科新种耳唇槽舌兰(Hotcoglossum auriculatum)进行了描述和绘图。该新种具有显著特征：萼片与花瓣基部有长爪;花瓣边缘具不规则齿或呈啮蚀状;唇瓣椭圆状圆形,边缘有短流苏或啮蚀状流苏,基部有爪和耳,极易区别于该属已知的种类,包括它的近缘种白唇槽舌兰(H．subulifolium)。     

黄土丘陵沟壑区撂荒地不同演替阶段植物群落的土壤抗蚀性——以坊塌流域为例

采用野外调查取样与室内试验相结合的方法,在分析土壤颗粒组成、级配状况与群体特性、团粒结构的分形特征及其稳定性变化的基础上,研究了黄土丘陵沟壑区撂荒地不同演替阶段植物群落的土壤抗蚀性.结果表明： 撂荒后植被从一年生草本群落阶段演替到多年生蒿禾类草本群落阶段的过程中,土壤的级配状况在不断改良,颗粒分形维数增大,团粒结构有所改善,土壤团粒结构的分形维数与结构体破坏率均不断减小,稳定性不断增强,从而提高了土壤的抗蚀性.实现植被的自然恢复对改善该区土壤结构、提高土壤抗蚀性、减少水土流失和促进区域生态环境可持续发展具有重要意义.     

The corrosion behaviour of galvanized steel in cooling tower water containing a biocide and a corrosion inhibitor

The corrosion behaviour of galvanized steel in cooling tower water containing a biocide and a corrosion inhibitor was investigated over a 10-month period in a hotel. Planktonic and sessile numbers of sulphate reducing bacteria (SRB) and heterotrophic bacteria were monitored. The corrosion rate was determined by the weight loss method. The corrosion products were analyzed by energy dispersive X-ray spectroscopy and X-ray diffraction. A mineralized, heterogeneous biofilm was observed on the coupons. Although a biocide and a corrosion inhibitor were regularly added to the cooling water, the results showed that microorganisms, such as SRB in the mixed species biofilm, caused corrosion of galvanized steel. It was observed that Zn layers on the test coupons were completely depleted after 3?months. The Fe concentrations in the biofilm showed significant correlations with the weight loss and carbohydrate concentration (respectively, p?<?0.01 and p?<?0.01).     

Biodegradation and corrosion behaviour of <Emphasis Type="Italic">Serratia marcescens</Emphasis> ACE2 isolated from an Indian diesel-transporting pipeline

A facultative anaerobic species Serratia marcescens ACE2 isolated from the corrosion products of a diesel-transporting pipeline in North West India was identified by 16S rDNA sequence analysis. The role of Serratia marcesens ACE2 on biodegradation of commercial corrosion inhibitor (CCI) and its influence on the corrosion of API 5LX steel has been enlightened. The degrading strain ACE2 is involved in the process of corrosion of steel API 5LX and also utilizes the inhibitor as organic source. The quantitative biodegradation efficiency of corrosion inhibitor was 58%, which was calculated by gas chromatography mass spectrum analysis. The effect of CCI on the growth of bacteria and its corrosion inhibition efficiency were investigated. Additionally, the role of this bacterium in corrosion of steel has been investigated by powder X-ray diffractometer (XRD) and scanning electron microscope studies. The presence of high-intensity ferric oxides and manganese oxides noticed from the XRD indicates that ACE2 enhances the corrosion process in presence of inhibitor as a carbon source. This basic study will be useful for the development of new approaches for the detection, monitoring and control of microbial corrosion in petroleum product pipelines.     

Use of surface analysis techniques to determine the mechanisms of metal corrosion in animal buildings

Recognizing the severity of metal corrosion problems in animal buildings has prompted an attempt to finally determine the fundamental causes of corrosion. Based on a two-year field test, this paper investigated the corrosion mechanisms of various metal products exposed in three animal buildings by analyzing the composition of corrosion products, using advanced material surface analysis techniques, including energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) analyses. Data from these analyses showed that the corrosion products were mainly iron oxides (Fe₂O₃, Fe₃O₄, and FeO) on uncoated 1010 carbon steel and zinc oxides, sulfides, and carbonates on galvanized steel and galvalume (ZnO, ZnS, Zn(CO)₃, and Al₂O₃). Thus, it could be concluded that the fundamental mechanisms of metal corrosion in animal buildings are similar to the classic corrosion mechanisms and the high corrosion rates of metal products in animal buildings are due to the presence of high moisture levels.     

Mathematical modelling of the degradation behaviour of biodegradable metals

A mathematical model for the biodegradation of magnesium is developed in this study to inspect the corrosion behaviour of biodegradable implants. The aim of this study was to provide a suitable framework for the assessment of the corrosion rate of magnesium which includes the process of formation/dissolution of the protective film. The model is intended to aid the design of implants with suitable geometries. The level-set method is used to follow the changing geometry of the implants during the corrosion process. A system of partial differential equations is formulated based on the physical and chemical processes that occur at the implant-medium boundary in order to simulate the effect of the formation of a protective film on the degradation rate. The experimental data from the literature on the corrosion of a high-purity magnesium sample immersed in simulated body fluid is used to calibrate the model. The model is then used to predict the degradation behaviour of a porous orthopaedic implant. The model successfully reproduces the precipitation of the corrosion products on the magnesium surface and the effect on the degradation rate. It can be used to simulate the implant degradation and the formation of the corrosion products on the surface of biodegradable magnesium implants with complex geometries.     

Comparative evaluation of the microbial community in biological processes treating industrial and domestic wastewaters

Aims: Comparison of the microbial composition and process performance between laboratory scale processes treating domestic and vegetable oil wastewaters. Methods and Results: Two laboratory scale modified Ludzack–Ettinger processes were operated under similar operating conditions. One process was fed domestic wastewater and the other an industrial wastewater, vegetable oil effluent. Nitrogen removal capacities of the processes were similar. The industrial process exhibited a lower COD removal capacity and oxygen utilization rate, although a greater mixed liquor volatile suspended solids concentration was observed in the industrial process. Fluorescent in situ hybridization (FISH) with probes EUBmix, ALF1b, BET42a, GAM42a and HGC69a revealed that 81% and 72% of total cells stained with 4′, 6‐diamidino‐2‐phenylindole (DAPI) within the domestic and industrial processes respectively bound to EUBmix. This indicated a slightly lower Eubacterial population within the industrial process. The alpha‐proteobacteria was the dominant community in the industrial process (31% of EUBmix), while the beta‐proteobacteria dominated the domestic process (33% of EUBmix). Conclusions: The findings served to establish a difference in the microbial population between the processes. Therefore, the class alpha‐proteobacteria could play a primary role in the degradation of vegetable oil effluent. Significance and Impact of the Study: This research will aid in process design and retrofitting of biological processes treating vegetable oil effluent.     

In situ corrosion control in industrial water systems

The main objective of this study was to evaluate the efficacy of a biocide and a corrosion inhibitor against the corrosion of a circulating pipe in a cooling tower. Isothiazolone was tested as the industrial biocide. The results showed that the biocide by itself or combined with a dispersant was not efficient to control corrosion in the industrial system. Corrosion rates of 0.324 mm/year were recorded in both the presence and absence of the biocide. Corrosion control was successfully accomplished by using a corrosion inhibitor. In the latter case the maximum corrosion rate of 0.024 mm/year were obtained.     

可降解镁合金材料在医学领域的研究和应用现状

作为最有潜力的第三代生物材料,新型可降解镁合金具有良好的生物相容性,与人体骨骼相近的力学性能,可避免二次手 术带来的不良影响等诸多优点,已成为当今研究的热点之一。然而镁合金在医学中的应用也受到其降解速度过快和随之引起机 械完整性丧失的影响。随着对镁合金研究的深入,在控制降解方面的研究已有显著成效。目前关于镁合金的研究主要集中在改善 其生物相容性、耐腐蚀性和机械性能等方面。本文将从镁合金降解产物对机体的影响,降解速度的控制和在医学中应用对其在当 今科研领域的研究进行综述。     

The effects of DDE, PCB and chlordane on the binding of progesterone to its cytoplasmic receptor in the eggshell gland mucosa of birds and the endometrium of mammalian uterus

1. The specific binding of progesterone to its cytoplasmic receptor in the mucosa of the shell gland from egg-laying ducks, domestic fowls and from the endometrium of the rabbit uterus was compared. The effect of DDE, PCBs and chlordane added in vitro was also studied. 2. The KD value for progesterone with regard to its receptor was about four times lower in the domestic fowl and the rabbit than in the duck. 3. The chlorinated hydrocarbons decreased the binding of progesterone to its receptor. Their potency was higher in the duck than in the domestic fowl. In rabbit uterine mucosa their effects were similar to those observed in the duck. 4. DDE is an inhibitor of calmodulin: other calmodulin inhibitors as calmidazolium and trifluoperazin also reduced the binding of progesterone in similar concentrations. It is suggested that DDE reduced the progesterone binding by inhibiting calmodulin.     

Corrosion behavior of carbon steel in the presence of two novel iron-oxidizing bacteria isolated from sewage treatment plants

In this work, two novel iron oxidizing bacteria (IOB), namely Gordonia sp. MZ-89 and Enterobacter sp. M01101, were isolated from sewage treatment plants and identified by biochemical and molecular methods. Then, microbially influenced corrosion (MIC) of carbon steel in the presence of these bacteria was investigated. The electrochemical techniques such as potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS) were used to measure the corrosion rate and observe the corrosion mechanism. The results showed that the existence of these microorganisms decreased the corrosion potential and enhanced the corrosion rate. Scanning electron microscopy (SEM) images revealed the ground boundary attacks and pitting on carbon steel samples in the presence of these bacteria after polarization. Corrosion scales were identified with X-ray diffraction (XRD). It was demonstrated that these bacteria can greatly affect the crystalline phase of corrosion products that also confirmed by SEM results. It was inferred that these bacteria were responsible for the corrosion of carbon steel, especially in the form of localized corrosion.