不同培养条件对环草石斛愈伤组织中次生代谢产物的影响

[目的]探索环草石斛生长与其主要的次生代谢产物——石斛碱和石斛多糖积累之间的关系。[方法]用苯酚-浓硫酸法和溴甲酚绿酸性染料比色法测定了不同培养条件对环草石斛愈伤组织中的多糖和总生物碱含量的影响。[结果]环草石斛悬浮培养的愈伤组织生长曲线呈"S"型。在光照条件下,环草石斛悬浮培养的愈伤组织中总生物碱和多糖含量的积累与其生长基本同步,光照有利于悬浮培养愈伤组织的生长和多糖的积累;在暗培养条件下,愈伤组织生长缓慢,多糖的积累不与其生长同步,但暗培养却可以提高愈伤组织中总生物碱的含量。[结论]环草石斛生长与其主要的次生代谢产物——总生物碱和石斛多糖积累之间有着密切的关系,不同培养条件对环草石斛中次生代谢产物具有一定的影响。

环草石斛愈伤组织和拟原球茎中生物碱和多糖含量的研究

用苯酚-浓硫酸法和溴甲酚绿酸性染料比色法测定了不同培养条件下得到的环草石斛愈伤组织和拟原球茎中总生物碱和多糖的含量。结果表明,愈伤组织和拟原球茎具备了代替原植物作为药用和提取原药成分的可能性;悬浮培养的愈伤组织中总生物碱和多糖的含量最高。该研究结果为从环草石斛愈伤组织中直接提取原药成分的研究提供了参考。

体外震波碎石配合磁疗排石疗法和机理初探

用JT-ESWL-Ⅱ型碎石机震碎肾和输尿管结石有效率高,但排石率不高,解放军303医院罗信善等采用旋磁仪治疗排石,效果显著。方法:将XCL-4型旋磁仪磁头置于结石石路阻塞的体表相应位置,每天1次或2次,每次30分钟。本组取肾结石29例、输尿管结石7例,其中1、2次震波后29例,3—6次震波碎石7例。结果2周内排净17例,40天内排净8例。

NMR research on deterioration characteristics of microscopic structure of sandstones in freeze-thaw cycles

In order to study the deterioration characteristics of the microscopic structure of sandstones in freeze-thaw cycles, tests of180 freeze-thaw cycles were performed on sandstone specimens. The nuclear magnetic resonance （NMR） technique was applied tothe measurement of sandstone specimens and analysis of the magnetic resonance imaging. Then, the fractal theory was employed tocompute the fractal dimension values of pore development of rocks after different freeze-thaw cycles. The results show that the massand porosity of rocks grow with the increase of freeze-thaw cycles. According to the NMR T2 distribution of sandstones, the poresizes of rock specimens increase after 180 freeze-thaw cycles, especially that of the medium-sized and small-sized pores. The spatialdistribution of sandstone pores after freeze-thaw cycles has fractal features within certain range, and the fractal dimension ofsandstones tends to increase gradually.

Experimental Study on Damage Properties of Rocks Under Dynamic Loading

The damage properties of two types of rocks under dynamic loading are studied. The shock induced experiments are done using planar impact technique on the one? stage light gas gun, and the ultrasonic tests on the damaged rocks have been made by use of the ultrasonic pulse? transmission method. The shock induced damage of rock is related to the shock speed and the attenuation coefficient of sonic wave, and the latter reflects the damage degree in rock fairly well. The attenuation coefficient α can be used as main damage parameter for constructing damage model of rock under dynamic loading.

日本纺绩协会对劳动事故的调查

日本纺绩协会技术委员会从1979年起就劳动事故问题对17个成员公司进行了调查,结果如下:据统计,被调查的17个成员公司的77～95个纺织工厂,约450万纺锭,2万台织机,1979年发生事故57件,1986年减少为33件.纺部以每10万锭计算,事故件数从1979年的0.5件上升到1984年的0.7件.据调查,产生事故的原因有六种:1)操作方法不正确(占事故总数的36%),2)疏忽大意(占总数的19%),3)思想不重视(占总数的7%),4)不停车操作(占总数16%),5)缺少操作指导(占总数7%),6)其他.

Damage constitutive model for strain-softening rock based on normal distribution and its parameter determination

Firstly, using the damage model for rock based on Lemaitre hypothesis about strain equivalence, a new technique for measuring strength of rock micro-cells by adopting the Mohr-Coulomb criterion was developed, and a statistical damage evolution equation was established based on the property that strength of micro-cells is consistent with normal distribution function, through discussing the characteristics of random distributions for strength of micro-cells, then a statistical damage constitutive model that can simulate the full process of rock strain softening under specific confining pressure was set up. Secondly, a new method to determine the model parameters which can be applied to the situations under different confining pressures was proposed, by deeply studying the relations between the model parameters and characteristic parameters of the full stress-strain curve under different confining pressures. Therefore, a unified statistical damage constitutive model for rock softening which can reflect the effect of different confining pressures was set up. This model makes the physical property of model parameters explicit, contains only conventional mechanical parameters, and leads its application more convenient. Finally, the rationality of this model and its parameters-determining method were identified via comparative analyses between theoretical and experimental curves.

Study on the cutting plane friction law of sandstone

The friction characteristics of rock damage plane have important impact on the stability of block structure formed after the stratum is broken. The mechanics properties of rock damage plane are described by parameters such as roughness coefficient, wall compress strength and basic friction angle. These three coefficients for fine grain sandstone and medium granular sandstone and grit sandstone are test. The friction stress is researched at the condition of different normal compressive stress acting on the tension damage plane. The friction law of tension damage plane of sandstone abided by is summed up. This law will provide scientific basis for block structure stability judging in basic roof stratum and roof pressure intensity calculating.

Study on damages constitutive model of rocks based on lognormal distribution

The damage constitutive relation of entire rock failure process was established using the theory of representative volume element obeying the Iognormal distribution law, and the integrated damages constitutive model of rock under triaxial compression was established. Comparing with triaxial compression test result, it shows that this model correctly reflects the relationship of stress-strain. At the same time, according to the principle of the rock fatigue failure that conforms to completely the static entire process curve, a new method of establishing cyclic fatigue damage evolution equation was discussed, this method form is simple and the physics significance is clear, it may join preferably the damage relations of the rock static entire process curve.

钙离子对干旱胁迫下铁皮石斛愈伤组织保护酶系统的影响

采用铁皮石斛愈伤组织为材料,利用PEG6000模拟干旱胁迫,同时施以CaCl2或Ca(NO3)2两种外源钙处理,通过测定四种过氧化物酶系SOD、POD、ASP、CAT酶活性变化情况,研究铁皮石斛抗旱机制以及Ca2+对铁皮石斛抗旱性的影响,结果显示在干旱胁迫下,铁皮石斛体内会发生一系列生理响应机制,其中在过氧化物酶类中SOD、POD、ASP与干旱胁迫密切相关,可以作为考察铁皮石斛抗旱性的指标。通过适当钙处理,这三类酶的活性迅速提高或维持在较稳定的状态,并以此来消除干旱胁迫产生的危害。而CAT在中低程度干旱胁迫中变化不大,在重度干旱胁迫下活力下降较大,且钙处理对其影响不大。因此,本研究对于铁皮石斛愈伤组织在生长过程中减少活性氧积累以及维持膜结构的完整具有实际意义,也对铁皮石斛在组织培养、快速繁殖及抗逆栽培方面提供理论指导。

Damage and fragmentation of rock under experiencing impact load

The principle of energy dissipation in rock impacted by impulse loading was investigated. Associated with damage mechanics, a new method was proposed to calculate the cumulative damage of rock under a repeated loading at the damage stage, which was studied from the point of the action density of energy. The concept of abstract fractal characteristic of damage parameter was put forward based on the intrinsic physical meaning of damage, which was applied to the fragmentation phase of rock. The relationship between fractal damage and the number of fragments was set up. According to the principles of energy dissipation and dynamic fracture of rock experiencing impact load, the damage evolution equation in the fragmentation phase of rock was presented. The results of experiment show that the two methods coincide well with each other.

Effects of loading waveforms on rock damage using particle simulation method

The particle simulation method is used to study the effects of loading waveforms （i.e. square, sinusoidal and triangle waveforms） on rock damage at mesoscopic scale. Then some influencing factors on rock damage at the mesoscopic scale, such as loading frequency, stress amplitude, mean stress, confining pressure and loading sequence, are also investigated with sinusoidal waveform in detail. The related numerical results have demonstrated that： 1） the loading waveform has a certain effect on rock failure processes. The square waveform has the most damage within these waveforms, while the triangle waveform has less damage than sinusoidal waveform. In each cycle, the number of microscopic cracks increases in the loading stage, while it keeps nearly constant in the unloading stage. 2） The loading frequency, stress amplitude, mean stress, confining pressure and loading sequence have considerable effects on rock damage subjected to cyclic loading. The higher the loading frequency, stress amplitude and mean stress, the greater the damage the rock accumulated; in contrast, the lower the confining pressure, the greater the damage the rock has accumulated. 3） There is a threshold value of mean stress and stress amplitude, below which no further damage accumulated after the first few cycle loadings. 4） The high-to-low loading sequence has more damage than the low-to-high loading sequence, suggesting that the rock damage is loading-path dependent.

A damage constitutive model of rock-like materials containing a single crack under the action of chemical corrosion and uniaxial compression

To describe the deformation and strength characteristics of the corroded rock-like specimens containing a single crack under uniaxial compression,a damage constitutive model combining hydro-chemical damage with coupling damage of micro-flaws and macro-cracks is proposed.Firstly,based on phenomenological theory,the damage variable of the rock-like specimens subjected to water environment erosion and chemical corrosion is obtained.Secondly,a coupled damage variable for cracked rock-like specimens is derived based on the Lemaitre strain equivalence hypothesis,which combines the Weibull statistical damage model for micro-flaws and the fracture mechanics model for a macro single crack.Then,considering the residual strength characteristics of the rock-like materials,the damage variable is modified by introducing the correction coefficient,and the damage constitutive model of the corroded rock-like specimens with a single crack under uniaxial compression is established.The model is verified by comparing the experimental stress−strain curves,and the results are in good agreement with those provided in the literature.Finally,the correction coefficient of the damage variable proposed in this paper is discussed.The damage constitutive model developed in this paper provides an effective method to describe the stress−strain relationship and residual strength characteristics of the corroded rock-like specimens with a single crack under uniaxial compression.

CT IDENTIFICATION OF THE MECHANIC CHARACTERISTICS OF DAMAGE PROPAGATION OF ROCK

The computerized tomography technique is applied to study the damage propagation of rock for the first time in this paper. CT values and their distribution regularity of damage propaga-tion of rock are analyzed in detail. The relation between CT values and stresses (strains) of the damage propagation of rock is then discussed. This provides the foundation for establishing the constitutive relation of damage propagation of rock.

Acute transient hepatocellular injury in cholelithiasis and cholecystitis without evidence of choledocholithiasis

AIM： To investigate acute transient hepatocellular injury in patients with cholelithiasis and cholecystitis but no evidence of choledocholithiasis.METHODS： The medical records of patients with cholelithiasis who underwent cholecystectomy between July 2003 and June 2007 were retrospectively reviewed. Imaging studies to detect common bile duct （CBD） stones were performed in 186 patients, who constituted the study population. Biochemical liver tests before and after surgery, and with the presence or absence of CBD stones were analyzed.RESULTS： In 96 patients with cholelithiasis and cholecystitis without evidence of CBD stones, 49 （51.0%） had an alanine aminotransferase level elevated to 2-3 times the upper limit of normal, and 40 （41.2%） had an elevated aspartate aminotransferase level. Similar manifestations of hepatocellular injury were, as would be expected, even more obvious in the 90 patients with CBD stones. These markers of hepatocellular injury resolved almost completely within 2 wk to 1 mo after cholecystectomy. Compared to 59 patients with histologically less severe cholecystitisin the group undergoing urgent surgery （total 74 patients）, the 15 patients with a gangrenous gallbladder had a higher mean level of total bilirubin （2.14 ± 1.27 mg/dL vs 2.66 ± 2.97 mg/dL, P 〈 0.001） and white cell count （9480 ± 4681/μL vs 12840 ± 5273/μL, P = 0.018）.CONCLUSION： Acute hepatocellular injury in cholelithiasis and cholecystitis without choledocholithiasis is mild and transient. Hyperbilirubinemia and leukocytosis may predict severe inflammatory changes in the gallbladder.

Thermal-hydro-mechanical coupling damage model of brittle rock

Based on fluid mechanics, thermodynamics and damage mechanics, thermal-hydro-mechanical （THM） coupling damage model of brittle rock is established by analyzing THM coupling mechanism, where THM coupling damage variable DTHM is dominated by TH coupling damage variable DTH, TM coupling damage variable DTM and HM coupling damage variable DHM, and DTH is firstly expressed in term of dimensionless total thermal conductivity of the water Nu. Permeability test, uni-axial compression test and THM coupling test are conducted to measure the permeability, elastic modulus and THM coupling stress-strain curves of brittle rock. The tested values of THM coupling elastic modulus E＇HM are in good agreement with the predicted values of THM coupling elastic modulus ETHM, which can verify the newly established THM coupling damage model.

The advance and development of damage measurement technique of rock

The key problem of rock damage mechanics is that determination of the variable of rock damage and the establishment of damage constitutive relation of rock, which is inevitable involved in the measurement problem of rock. In this paper, the measurement technology and method of rock damage are comprehensively narrated, analyzed and studied. On the basis of the narrating the former study, a new method (Computerized Tomography,CT for short) is introduced, which is applied to rock damage measurement. On the other hand, some newest study results and laws in the field are also introduced, which are from some scholars, the author of this paper.

Properties of failure mode and thermal damage for limestone at high temperature

The mechanical properties of limestone such as the stress-strain curve, the variable characteristics of peak strength and the modulus of elasticity of limestone were studied under the action of temperatures ranging from room temperature to 800 °C.Our results show that:1) the temperature has not clear effect on the mechanical properties of limestone from room temperature to 600 °C.However, the mechanical properties of limestone deteriorate rapidly when the temperature is above 600 °C.In this case, the peak stress and modulus of elasticity decrease rapidly.When the temperature reaches 800 °C, the entire process, showing the stress-strain curve is displayed indicating an obvious state of plastic-deformation;2) the failure mode of limestone shows the breakdown of tensile strength from room temperature to 600 °C, as well as the compress shearing damage over 600 °C;3) combining our test results with the concept of thermal damage, a thermal damage equation was derived.

IRRIGATION AND TRACTION THERAPY FOR OPEN FRACTURE WITH LARGE－SIZED FULL－THICKNESS SKIN－DEFICIT AND SEVERELY INFECTED WOUND

In this paper the results of skeletal traction and irrigation therapy (STIT) used for open fracture complicated with large-sized full-thickness skin-deficit and infection wounds (OFIW) were presented. Fourteen patients of OFIW were treated by the plaster cast and wound dressing (PCWD), and 30 patients of OFIW were treated by STIT. The results indicated that after one week of treatment, the white blood cell count in the STIT group, compared to 17. 6±l. 0×109/L from before treatment, returned to 8. 8±0. 8×109/L,and in contrast, the cell count of the PCWD group was about 13. 0±1. 4×109/L. All of wound exudate culture in the STIT group was negative, and those of 7 cases (7/14) in PCWD group were positive (P<0. 0l). The symptoms and signs such as pain, fever and septic exudate on the wound in the STIT group were much milder than those in the PCWD group. There were 5 cases (35. 7%) of toxicemia and septicemia, 2 cases (14. 3%) of osteomyelitis, 2 cases (14. 3 %) of amputation, 1 case (7. 1%) of delayed union and 3 cases (21. 4 %) of malunion in the PCWD group, and no complications in the STIT group.