“以物化人”——物型化学在初中化学教学中的静悄悄革命

物型化学是初中化学教育理念的延展,“文化”可以理解为以文化人,那么“物化”则可理解为以物化人。物型化学就是通过物我合一培养学生的化学实证精神。文章论述了物型化学的几个明显特征:科学合理的教学设计、实景在场的生本体验以及精彩纷呈的小组汇报。

管腔型化学指示物灭菌过程挑战装置在压力蒸汽灭菌效果监测中的应用

目的观察管腔型化学指示物灭菌过程挑战装置(PCD)在压力蒸汽灭菌效果监测中的应用及其影响因素,为科学合格选用管腔型化学PCD提供参考。方法通过不同规格管腔PCD观察两种5类化学指示物对压力蒸汽灭菌过程的监测验证性能并作出评价。结果两种5类化学指示物在134℃脉动真空压力蒸汽灭菌器内规范灭菌程序条件下变色全部合格。把管腔型化学PCD分别置于灭菌器内排气口上方、灭菌器上层中部和灭菌器下层后门处等3个部位,合格率分别为94. 87%、96. 15和96. 15%。管腔PCD直径相同,其长度不同,化学PCD监测结果存在差异,监测失败均出现在管腔长度3 m及以上。结论在化学指示物合格的条件下,PCD管腔长度对结果产生影响,灭菌器内较难灭菌部位容易出现监测失败。

Hydrogen desorption kinetics mechanism of Mg-Ni hydride under isothermal and non-isothermal conditions

The Mg-Ni hydride was prepared by hydriding combustion synthesis under a high magnetic field. The dehydriding kinetics of the hydrides was measured under the isothermal and non-isothermal conditions. A model was applied to analyzing the kinetics behavior of Mg-Ni hydride. The calculation results show that the theoretical value and the experimental data can reach a good agreement, especially in the case of non-isothermal dehydriding. The rate-controlling step is the diffusion of hydrogen atoms in the solid solution. The sample prepared under magnetic field of 6 T under the isothermal condition can reach the best performance. The similar tendency was observed under the non-isothermal condition and the reason was discussed.

Velocity of a Liquid Drop with a Sorption-Controlled Surfactant

The terminal velocity of a liquid droplet settling in a sulfactant solution has been studied for the non-linear adsorption Langmuir frameworks accounting for monolayer saturation and non-ideal surfactant interactions. Most prior research uses a linear adsorption model which cannot capture these effects, The Maragoni migration of a liquid drop settling through a surfactant solution is examined by using Langmuir framework. The solution concentration Ceq is assumed large enough for the surfactant mass transfer to be adsorption-controlled. Langmuir model generates non-linear Marangoni stresses which diverge in the limit of approaching ∝, strongly retarding U'.

Correlation of Cooperatively Localized Rearrangement on the ＂Fluidized Domain＂ of Polymers to Their Nonexponentially Viscoelastic Behaviors at Double Aging Processes （I）： A Set of Reduced Universal Equations on the Stress Relaxation Modulus and Creep Comp

Based on the structure of glass （or liquid） polymers consisting of α-domain, β-co-domain, and entanglement constituent chain networks, and the nonexponentially viscoelastic behavior, a “heterophase fluctuation” model was proposed. It was found that the dynamics of cooperative rearrangement on the “fluidized domain” has a great shear rate, domain size, and temperature dependences. When the shear rate, domain size, and temperature dependences were taken account into the cooperatively localized rearrangement on the fluidized domain by the degradation of primary α-domain and the reformation of secondary β-co-domain constituent chains. A new dynamic theory of cooperatively localized rearrangement on the fluidized domain constituent chains with different size and different network chain length during physical and mechanical aging was established. The total viscoelastic free en-ergy of deformation resulting from the change in conformations of α-domain, β-co-domain, crytallite, crosslinked, and trapped entanglement constituent chains during aging processes was calculated by the combining method of kinetics and statistical mechanics. The constitu- tive equations and reduced stress relaxation modulus and creep compliances for three types of polymers were also derived. Finally, two reduced universal equations on creep compliance and stress relaxation modulus with a non-linear and two nonexponential parameters α and β were theoretically derived from the dynamic theory and a statistically extended mode coupling theory for double aging effects of polymers was developed. Results show that the two reduced universal equations have the same form as Kohlraush-Williams-Watts （K-W-W） stretched exponential function. The nonlinearity and the nonexponentiality are, respectively, originated from the memory effects of nonthermal and thermal history. The correlation of nonlinearity, α and β to the aging time, aging temperature, and the mesomorphic structure of fluidized domains was also established.

The Physical Models of Cyclone Diplegs in Fluidized Beds

In most industrial fluidization units, two- or three-stage cyclone systems are used to clean the product gases. To return the solids to the bed, these cyclones are fitted with diplegs. By pass of gas from the bed through the dipleg is partially overcome by the back pressure build-up in the dipleg and by adding a trickle valve at the bottom of the dipleg. Diplegs of primary cyclones, operating at a high solid loading behave differently from diplegs of secondary and tertiary cyclones which operate at low solid loading. Both types have been investigated by pressure drop measurements, visual observation and by measurements of the air flow rate flowing up the riser. The primary dipleg was also studied using electrical capacitance tomography. The results are reported hereafter and will give a first indication towards the right design of the dipleg and the selection of the trickle valve. The influence of gas flow in the dipleg on the conversion in a catalytic fluidized bed reactor is found to be negligible.

Modeling transportation of suspended solids in Zhujiang River estuary, South China

A three-dimensional transportation model for suspended solids (SS) in Zhujiang (Pearl) River estuary, South China, was developed by coupling with a three-dimensional hydrodynamic model. The model was validated using hourly measured data of sediment contents during 25–26, July 1999. The results showed that modeled contents matched well with measured ones and that the modeled top layer distribution agreed with the remotely sensed image of suspended solids in summer. The modeled results showed clearly the layers of sus- pended solids in depth, with larger sediment contents in lower layers though in the interface between salt water and freshwater the lowest contents appeared in middle layer. In overall, the suspended solids inflow from 8 rivers, transport southwestward, and carried by strong coastal flow in Zhujiang River estuary. Contours of sediment contents in the estuary spread further to the open sea during ebb tide rather than flood tide which reflects that the suspended solids in the estuary are land sourced.

Virological course of hepatitis A virus as determined by real time RT-PCR: Correlation with biochemical, immunological and genotypic profiles

AIM： To undertake analysis of hepatitis A viral load, alanine aminotransferase （ALT）, and viral genotypes with duration of viremia, and to correlate these parameters with CD4^＋/ CD8^＋ lymphocyte populations that control cell-mediated immunity. METHODS： Cell counts were carried out using fresh whole blood collected in EDTA vials using a fluorescence activated cell sorter. Hepatitis A virus （HAV） RNA was extracted from blood serum, reverse transcribed into cDNA and quantified by Real-Time polymerase chain reaction and was genotyped. RESULTS： Among 11 patients, 10 could be analyzed completely. Of these, 3 had severe acute hepatitis （s-AH） and the remainder had a self-limited acute hepatitis A （AHA）, with one patient with fulminant disease （encephalopathy Grade IV） dying on the 4^th d. The ALT level was significantly higher both in AHA （1070.9±894.3; P = 0.0014） and s-AH （1713.9±886.3; P = 0.001） compared to normal controls （23.6±7.2）. The prothrombin time in s-AH patients （21.0 ±2.0; P=0.02） was significantly higher than in AHA （14.3±1.1;P = 0.44）. The CD4^＋/CD8^＋ ratio in AHA patients （1.17 ＋ 0.11; P = 0.22） and s-AH （0.83 ＋ 0.12; P = 0.0002） were lower than seen in normal healthy controls （1.52）. Self-limited cases had peak viral load at the beginning of analysis while in s-AH patients this occurred at the 15TM or 30^th d. In acute and severe groups, one patient each belonged to genotype IA, with the remaining 8 cases belonging to genotype IIIA. The only fulminant hepatic failure case belonged to genotype IA. HAV viral load and AIT values collected during the entire course of the selflimited infection were directly correlated but this was not the case for s-AH patients.CONCLUSION： Based on a small-scale study, the persistently higher viral load of s-AH might be due to diminished cellular immunity and hemolysis. The duration of viremia was dependent on the host, as the viral genotype had no apparent role in clinical outcome of AVH and s-AH cases.

Distribution and Assessment of Soil and Land Degradation in Subtropical China—A Case Study of the Dongxi River Basin, Fujian Province *1

Some alternative methods for estimating soil erosion rates rapidly were used to elucidate the relationship between the land use types and land degradation. The 137 Cs content, magnetic susceptibility, aggregate stability, and soil properties were studied in the Dongxi River Basin, a mountainous area of western Fujian. A plot of 137 Cs inventory (Y) against slope angle (X) shows a strong inverse log log relationship ( r = -0.83 ), indicating that much more soil erosion occurs on steeper slopes. Average soil loss (in thickness of top soil per year) in the past 30 years for arable slope crest, arable slopes and tea plantation slopes are 1.6 , 10.4 and 8.0 mm year -1 respectively. The surface layer enrichment factor of magnetic susceptibility (Y) in soil also shows an inverse log log relationship ( r =-0.63), indicating a similar tendency with the relationship between the 137 Cs inventory (Y) against slope angle (X). The physical and chemical properties of soils among different land use types show different degraded characteristics at different significant levels.

Diagnostic accuracy of serum biochemical fibrosis markers in children with chronic hepatitis B evaluated by receiver operating characteristics analysis

METHODS： We determined the serum level of apolipoprotein A-I （APO A-I）, haptoglobin （HPT） and a-2 macroglobulin （A2I） with an automatic nephelometer in 63 children （age range 4-17 years, mean 10 years） with biopsy-verified chronic HBeAg-positive hepatitis B. Fibrosis stage and inflammation grade were assessed in a blinded fashion according to Batts and Ludwig. We defined mild liver fibrosis as a score ≤2 and advanced fibrosis as a score equal to 3. ROC analysis was used to calculate the power of the assays to detect advanced liver fibrosis （AccuROC, Canada）. RESULTS： Serum concentrations of APO A-I, HPT and A2M were not significantly different in patients with chronic hepatitis B compared to controls. However, APO A-I level of 1.19 ng/L had a sensitivity of 85.7% and a specificity of 60.7% （AUC = 0.7117, P = 0.035） to predict advanced fibrosis. All other serum biochemical markers and their combination did not allow a useful prediction. None of these markers was a good predictor of histologic inflammation. CONCLUSION： Apolipoprotein A-I may be a suitable serum marker to predict advanced liver fibrosis in children with chronic hepatitis B.

Geochemical Forms of Phosphorus in Sediments of Three Large, Shallow Lakes of China

A sequential extraction method for the fractionation of phosphorus （P） in lake sediments was used to analyze phos- phorus fractions of sediments taken from three large, shallow. eutrophic freshwater lakes of China-Talhu Lake. Chaohu Lake, and Long.an Lake. All three lakes are located in the lower reaches of the Changjiang River （Yangtze River）. In Taihu Lake and Chaohu Lake, algae blooms occurred every year, while Longgan Lake was a macrophyte-dominated lake. Results showed that exchangeable phosphorus fractions were much higher in the eutrophic lake sediments than in the macrophyte-flourishing lake sediment. Also, the ratio of Fe：P in the sediments of the algae-predomlnant lakes was generally much lower than that in the macrophyte-predominant lakes. Thus, the geochemical fractions of phosphorus in sediments had a closer relationship with the type of aquatic vegetation.

Degradation of Organic Pollutants by the Advanced Oxidation Processes

A kinetic model has been developed for the degradation of organic pollutants concerning with hydroperoxide ion as the initial step for generation of hydroxyl radical and its subsequent reaction mechanisms. Rate equations were derived for depletion of ozone and pollutants in the peroxone oxidation process using ozone and hydrogen peroxide as combined oxidants. Kinetic data obtained experimentally from the hydrogen peroxide-ozone reaction and peroxone oxidation of nitrobenzene were analyzed by using the proposed rate equations.

A novel model for cost performance evaluation of pulverized coal injected into blast furnace based on effective calorific value

The combustion process of pulverized coal injected into blast furnace involves a lot of physical and chemical reactions. Based on the combustion behaviors of pulverized coal, the conception of coal effective calorific value representing the actual thermal energy provided for blast furnace was proposed. A cost performance evaluation model of coal injection was built up for the optimal selection of various kinds of coal based on effective calorific value. The model contains two indicators: coal effective calorific value which has eight sub-indicators and coal injection cost which includes four sub-indicators. In addition, the calculation principle and application of cost performance evaluation model in a Chinese large-scale iron and steel company were comprehensively introduced. The evaluation results finally confirm that this novel model is of great significance to the optimal selection of blast furnace pulverized coal.

A Unified Model for the Degradation Kinetics of Pesticides Applied Continually to Soils

This paper deduces a kinetic model for microbial degradation of pesticides in soils:where x is the concentration of pesticide at time t, so the initial concentration of the pesticide, me the initial number of pesticide-degrading microorganisms, M the carrying capacity for the microorganisms, μ the specific growth rate of the microorganisms, and k the rate constant for the pesticide degradation.In periodic applications of pesticides, this model can be used to continuously describe every degradation curve. Whether a lag phase occurs or not, we can obtain the minimum residue of the pesticide (xe):xe=xdexp(-kMr)/[1-exp(-ker) ]where r is the regular time internals between applications, and xd the dosage of the pesticide.

Pegylated-interferon alpha 2a treatment for chronic hepatitis C in patients on chronic haemodialysis

AIM： To evaluate the response to pegylated-interferon alpha 2a in chronic hepatitis C patients on chronic haemodialysis. METHODS： Ten patients with chronic C hepatitis were enrolled in this study. All had increased aminotransferases for more than 6 too, positive antiHCV antibodies and positive PCR HCV-RNA. We administrated Peg-Interferon alpha 2a 180 μg/wk for 48 wk. After 12 wk of treatment we evaluated the biochemical and early virological response （EVR）. At the end of the treatment we evaluated the biochemical response and 24 wk after the end of the treatment we evaluated the sustained virological response （SVR）. We monitored the sideeffects during the treatment. RESULTS： Two patients dropped out in the first 12 wk of treatment and 2 after the first 12 wk of treatment. After 12 wk of treatment, 7 out of 8 patients had biochemical response and EVR and 1 had biochemical response but persistent viremia. We had to reduce the dose of pegylated-interferon to 135 μg/wk in 2 cases. Three out of 6 （50%） patients had SVR 24 wk after the end of the treatment. Intention-to-treat analysis showed that 3 out of 10 patients （30%） had SVR. Side-effects occurred in most of the patients （flu-like syndrome, thrombocytopenia or leucopoenia）, but they did not impose the discontinuation of treatment. CONCLUSION： After 12 wk of treatment with Peg-Interferon alpha 2a （40 ku） in patients on chronic haemodialysis with chronic C hepatitis, EVR was obtained in 87.5% （7/8） of the cases. SVR was achieved in 50% of the cases （3/6 patients） that finished the 48 wk of treatment.

Bio-dissolution of pyrite by Phanerochaete chrysosporium

The dissolution of pyrite was studied with Phanerochaete chrysosporium(P.chrysosporium).This fungus resulted in the dissolution of 18%iron and 33%sulfur.The oxidization layer was formed on the pyrite surface,which probably consisted of iron oxide,iron oxy-hydroxide,iron sulfate,elemental sulfur and mycelia.The electrochemical characteristics of pyrite were studied in the systems without and with P.chrysosporium.P.chrysosporium could accelerate the dissolution of pyrite by decreasing pitting potential and polarization resistance plus improving polarization current,corrosion potential and corrosion current density.The dissolution of pyrite is the combined effect of enzymes,hydrogen peroxide,ferric iron and organic acids.Enzymes attack the chemical bonds by free radicals.Organic acids dissolve pyrite by acidolysis and complexolysis.Enzymes and hydrogen peroxide play an essential role in this process.

Use of chemically activated cotton nut shell carbon for the removal of fluoride contaminated drinking water: Kinetics evaluation

Chemically activated cotton nut shell carbons （CTNSCs） were prepared by different chemicals and they were used for the removal of fluoride from aqueous solution. Effects of adsorption time, adsorbent dose, pH of the solution, initial concentration of fluoride, and temperature of the solution were studied with equilibrium, ther- modynamics and kinetics of the adsorption process by various CTNSC adsorbents. It showed that the chemically activated CTNSCs can effectively remove fluoride from the solution. The adsorption equilibrium data correlate well with the Freundlich isotherm model. The adsorption of fluoride by the chemically activated CTNSC is spon- taneous and endothermic in nature. The pseudo first order, pseudo second order and intra particle diffusion kinetic models were applied to test the experimental data. The pseudo second order kinetic model provided a better correlation of the experimental data in comparison with the pseudo-first-order and intra particle diffusion models, A mechanism of fluoride adsorption associating chemisorption and physisorption processes is presented allowing the discussion of the variations in adsorption behavior between these materials in terms of specific surface area and porosity. These data suggest that chemically activated CTNSCs are promising materials for fluoride somtion.

Homology modeling and evolutionary trace analysis of superoxide dismutase from extremophile Acidithiobacillus ferrooxidans

The gene sod in Acidithiobacillusferrooxidans may play a crucial role in its tolerance to the extremely acidic, toxic and oxidative environment of bioleaching. For insight into the anti-toxic mechanism of the bacteria, a three-dimensional （3D） molecular structure of the protein encoded by this gene was built by homology modeling techniques, refined by molecular dynamics simulations, assessed by PROFILE-3D and PROSTAT programs and its key residues were further detected by evolutionary trace analysis. Through these procedures, some trace residues were identified and spatially clustered. Among them, the residues of Asn38, Glyl03 and Glul61 are randomly scattered throughout the mapped structure; interestingly, the other residues are all distinctly clustered in a subgroup near Fe atom. From these results, this gene can be confirmed at 3D level to encode the Fe-depending superoxide dismutase and subsequently play an anti-toxic role. Furthermore, the detected key residues around Fe binding site can be conjectured to be directly responsible for Fe binding and catalytic function.

Biochemical response to lamivudine treatment in HBeAg negative chronic hepatitis B patients in Iran

AIM： To study the effect of a one-year lamivudine regimen in patients with chronic hepatitis B. METHODS： Medical records of HBeAg negative hepatitis B patients who attended a hepatitis clinic in Tehran between March 2002-March 2004 were evaluated. The patients received 100 mg lamivudine tablets once daily for at least 12 mo. Liver enzymes and complete blood count were checked at baseline and the end of treatment （12th mo） and 6 mo after discontinuation of treatment. RESULTS： Of all patients, 24 were excluded. Of 71 patients left, 58 （81.7%） were men. Mean age of the patients was 38 ± 14 years. Mean level of ALT in serum was 1437 ± 205 nkat/L at baseline with a significant reduction at the end of treatment to a mean level of 723 ± 92 nkat/L （P = 0.002）. In 38 patients （53.5%）, the ALT level was normal after one-year treatment. Five patients （7.3%） relapsed （biochemically） within 6 mo after discontinuing lamivudine therapy （the patients with good end of treatment response）. Mean level of AST in serum was 1060 ± 105 nkat/L at baseline which decreased significantly to 652 ± 75 nkat/L at the end of treatment （P = 0.002）. CONCLUSION： Over half （53.5%） of chronic hepatitis B patients with HBeAg negative have normal liver enzyme level at 12-mo lamivudine therapy.

Modeling the Effects of Nutrient Dynamics and Surface Circulation on the Productivity of Hooghly Estuary

River estuarine environment plays a key role in the cycling of biological and chemical parameters and a significant region for the transaction of freshwater and seawater. In the present study, a first attempt has been made towards the development of a coupled three-dimensional hydrodynamic circulation model with four compartment （nitrate, phytoplankton, zooplankton and detritus） biogeochemical model in the Hooghly estuary （21 °36′-22° 16′1 and 87°42＇-88°15′E） to simulate the varying effect of plankton biomass with the heavy input of anthropogenic litter from industrial effluents of Haldia port which is effecting the chemical and biological processes that control the plankton dynamics in the estuary. In-situ observational data for physico-chemical and biological parameters are collected from Calcutta University during 2010 are assimilated using multiscale OA （objective analysis） for different seasons and incorporated in ROMS （Regional Ocean Modeling System） to develop a high resolution （0.5 km x 0.5 kin） biogeochemical model. Recent analysis on physico-chemical parameters of the estuary is done as it is one of the largest estuaries in India and is the habitat for vast biodiversity. Influence of high nitrate （above 34 μg/L） and phosphate （5.22 μg/L） is predominant whereas DO （dissolved oxygen） is low （4.07 mg/L） in the Haldi River mouth which is sliding the productivity （less than 1 mg/L） and also affects water quality.