拟环的强素根

本文定义了强素Ｎ－群的概念，利用它给出拟环Ｎ的强素根σ（Ｎ）的模刻划，证明了σ：Ｎ→σ（Ｎ）是根映射且σ（Ｉ）＝σ（Ｎ）∩Ｉ，其中ＩＮ是Ｎ的直和项．

拟环强素根的模刻划

给出拟环N的强素根S(N)的模刻划 ,证明了S :N→S(N)是根映射且S(I) =S(N)∩I,其中I N是N的直和项 .最后得到了有关US_素根及US(1)

强素Γ－模

类似环上模定义Γ－环Ｍ的强素模的概念，通过强素ＭΓ－模给出Ｍｒ－模的强素根的刻划．引入ｓｆ－系的概念，并用它刻划强素模、强素根．讨论了Γ－环Ｍ的强素模与Γ－环Ｍ的右算子环Ｒ的强素模之间的关系．

拟环的强素根

本文闸明魏宗宣引进的根是拟环的一种新根,它不同于Van der Walt的素根和Groenwald的完全素根,将其称之为强素根。

关于强素子模

本文定义了强素理想,强素子模及环的m*-系和模的m*-系,且给出了它们之间的两个等价关系:(1)设L是环R的理想,那么L是R的强素左理想当且仅当C(L)=R-L是m*-系;(2)设K是左R-模M的子模,那么K是M的强素子模当且仅当C(K)=M-K是m*-系.

R_0代数上的MP滤子格

在R0代数M的全体M P滤子集F(M)上定义格运算和伴随对,证明如此定义的M P滤子格F(M)也构成一个剩余格。在R0代数M的强素M P滤子子格F P(M)上引进一个逆序对合对应,得到了强素M P滤子子格F P(M)是一个拟布尔代数。

Influencing factors analysis of hard limestone reformation and strength weakening under acidic effect

Roof disaster has always been an important factor restricting coal mine safety production.Acidic effect can reform the rock mass structure to weaken the macroscopic strength characteristics,which is an effective way to control the hard limestone roof.In this study,the effects of various factors on the reaction characteristics and mechanical properties of limestone were analyzed.The results show that the acid with stronger hydrogen production capacity after ionization(pK_(a)<0)has more prominent damage to the mineral grains of limestone.When pKa increases from−8.00 to 15.70,uniaxial compressive strength and elastic modulus of limestone increase by 117.22%and 75.98%.The influence of acid concentration is manifested in the dissolution behavior of mineral crystals,the crystal defects caused by large-scale acid action will lead to the deterioration of limestone strength,and the strength after 15%concentration reformation can be reduced by 59.42%.The effect of acidification time on limestone has stages and is the most obvious in the initial metathesis reaction stage(within 60 min).The key to the strength damage of acidified limestone is the participation of hydrogen ions in the reaction system.Based on the analytic hierarchy process method,the influence weights of acid type,acid concentration and acidification time on strength are 24.30%,59.54% and 16.16%,respectively.The research results provide theoretical support for the acidification control of hard limestone roofs in coal mines.

环与其商环的若干类理想

本文讨论一个环R与其商环R/I之间关于若干类理想的关系.设I■K■R且K是R的理想,我们证明了K是R的二素理想(强素理想,左T-幂零理想,根对称理想)当且仅当K/I是商环R/I的二素理想(强素理想,左T-幂零理想,根对称理想).

Photoinhibition in Shaded Cotton Leaves After Exposing to High Light and the Time Course of Its Restoration

Chlorophyll fluorescence emission, pigment composition and photosynthetic rate of shade-grown cotton ( Gossypium hirsutum L.) plants were measured immediately after suddenly exposing to full sunlight and at regular intervals there after within 15 d. Photoinhibition occurred in shade-grown cotton leaves immediately after exposed to full sunlight. The chlorophyll fluorescence parameter F-v/F-m and PhiPS II, which reflect the efficiency of PS II,obviously decreased in shade-grown leaves, much lower than that of the full sunlight-grown leaves. On the contrary, F-o value was sharply increased. Neither of these parameters could completely recover till next morning. The photoinhibition was chronic and continued for about 4 d, while the F-v/F-m and the net photosynthetic rate ( P-n) continued to decline, then began to increase gradually 6 d later and turned stable after 10 - 12 d, appearing as an acclimation phenomenon. However, the final value of F-v/F-m and P-n did not reach the level as in those leaves grown in the full sunlight ever before. The final P-n was higher by 60% than that before exposure, but lower for more than 40% than that of the full sunlight-grown leaves. The most notable response of chloroplast pigment composition was a pronounced increase in the pool size of carotenoids in xanthophyll cycle over a period of 3 d. The results indicated that when shade-grown cotton seedlings were suddenly transferred to the full sunlight, the decline of F-v/F-m and P-n might associate with the damage of the PS II reaction center. During the light acclimation, photoprotective mechanisms such as the xanthophyll cycle-dependent energy dissipation were increased, so that photodamage in leaves transferred from low to high light might be reduced.

Effect of minor B addition on microstructure and properties of AlCoCrFeNi multi-compenent alloy

The influences of slight amount of B element on the microstructure and properties of AlCoCrFeNiBx high entropy alloys（x = 0,0.01,…,0.09 and 0.1,mole fraction） were investigated.The AlCoCrFeNi high entropy alloy exhibits equiaxed grain structures with obvious composition segregation.However,with the addition of B element,the alloys exhibit dendrite structures.Inside the dendrites,spinodal decomposition structure can be clearly observed.With the addition of B element,the crystal structures change from（B2 ＋ BCC） to（B2 ＋ BCC ＋ FCC） structures,and the hardness firstly increases from HV 486.7 to HV 502.4,then declines to HV 460.7（x ≥ 0.02）.The compressive fracture strength firstly shows a trend of increasing,and then declining（x ≥ 0.08）.The coercive forces and the specific saturation magnetizations of the alloys decrease as B addition contents increase,the decreasing coercive forces show a better soft magnetic behavior.

分次环的分次分式环

设R是G-分次环,给出了分次环R和它的分次右分式环Q_G(R)的相关性质:分次强素性,分次非奇异性,分次半素性。

Multivariate Analysis of Recurrence in Meningioma

Objective: To evaluate the clinical and radiological factors that affect therecurrence of the meningioma patient so as to effectively prevent and cure recurrence of meningiomapatients more earlier. Methods: The clinical features and radiological aspects in 145 cases ofmeningiomas undergoing operation during 1993-1997 were retrospectively studied. The data of only 83cases of all 145 cases were available. The factors were evaluated with univariate and multivariateanalysis. Results: With univariate analysis, 7 factors showed highly significance to recurrence ofmeningiomas: tumor size, tumor location, tumor shape, edema, extent of resection, pathologicalgrade, CT enhancement. With multivariate analysis, 4 factors showed significant danger to recurrenceof meningiomas: pathological grade, extent of resection, tumor shape and CT enhancement.Conclusion: The main factors that affect the recurrence of meningioma patients are pathologicalgrade, extent of resection, tumor shape and CT enhancement.

Effects of Ti and Be addition on microstructure and mechanical properties of Mg_(58.5)Cu_(30.5)Y_(11) bulk metallic glass

Based on the Mg58.5Cu30.5Y11 alloy, 10% Ti, 10% Be and 10% Ti70Be30 （mole fraction） were respectively added to the alloy and samples with a diameter of 3 mm were fabricated by conventional Cu-mold casting method. The phase constituent, thermal stability and microstructure of the alloys were investigated by using X-ray diffraction, differential scanning calorimetry and scanning electron microscopy, respectively. The effects of alloying elements Ti and Be on the microstructure and mechanical properties of Mg58.sCu3o.sYll alloy were discussed. The results show that CuTi phase is distributed in （Mg0.585Cu0.305Y0.11）90Ti10 and （Mg58.5Cu30.5Y11）90（Ti0.7Be0.3）10 alloys, while CuYBe glassy phase containing CuY crystals is embedded in the matrix of （Mg58.5Cu30.5Y11）90Be10 alloy. Under uniaxial compressive loading, the largest compressive fracture strengths for （Mg58.5Cu30.5Y11）90Ti10, （Mg58.5Cu30.5Y11）90Be10 and （Mg58.5Cu30.5Y11）90（Ti0.7Be0.3）10 alloys are 797.6, 952.6 and 1007.8 MPa, respectively, and the strengths are increased by about 17%, 40% and 48% compared with Mg58.5Cu30.5Y11 alloy. The strength reliability for the three alloys is much improved according to the strength distribution region of 10 samples of each alloy.

Effect of Radiative Forcing on Growth and Photosynthetic Responses of Elaeocarpus glabripetalus Merr.

[Objective] This study aimed to reveal the impact of radiative forcing on the woody plants in subtropical regions of China through the study on the effect of radiative forcing on growth and photosynthetic responses of Elaecarpus glabripetalus Merr. seedlings. [Method] Three gradients of radiative forcing treatments were applied to the species namely, control group （100% natural light）, weak radiative forcing group （39% natural light） and strong radiative forcing group （16% natural light）. The relative contents of chlorophyll, photosynthetic parameters of E. glabripetalus in different periods were measured to analyze the effects of different gradients of radiative forcing on plant height, ground diameter, chlorophyll content, gas exchange parameters, light response cure parameters. [Result] The increased ground diameter of E. glabripetalus in different treatments was the control weak radiative forcing group strong radiative forcing group; the increased plant height in the early period was strong radiative forcing group weak radiative forcing group control, but there was no significant difference during the late period; the relative content of chlorophyll was strong radiative forcing group weak radiative forcing group control. The light compensation point （LCP）, light saturation point （LSP） and the maximum net photosynthetic rate （A max ） were reduced in radiative forcing treatments. The stomatal conductance （G s ）, transpiration rate （Tr） of E. glabripetalus in strong radiative forcing group were significantly smaller than that in the control group, while there was no significant change in dark respiration rate （R d ） and apparent quantum yield （AQY）. [Conclusion] In summary, the radiative forcing can change the environmental factors which have significant effect on the ground diameter, plant height, relative content of chlorophyll and photosynthetic physiological parameters, but with the processing of treatment the effects on ground diameter and plant height increase are not significant in the late period, indicating that E. glabripetalus seedlings have some resistance and adaptability to the radiative forcing environment.

Photochemical Efficiency of PSⅡ and Membrane Lipid Peroxidation in Leaves of indica and japonica Rice (Oryza sativa) Under Chilling Temperature and Strong Light Stress Conditions

Relationships between fluorescence parameters and membrane lipid peroxidation in leaves of indica and japonica rice (Oryza sativa L.) during later growth stage were studied under chilling temperature and strong light stress conditions. Results showed that D1 protein contents of PSⅡ in photosynthetic apparatus dropped, the generation of antheraxanthin (A) and zeaxanthin (Z) of xanthophyll cycle were inhibited partly, PSⅡ photochemical efficiency (F v/F m)and non-photochemical quenching (q N) were also decreased obviously. In addition, endogenous active oxygen scavenger—superoxide dismutase (SOD) reduced, superoxide anion radical (O -· 2) and malondialdehyde (MDA) accumulated, as a result, photooxidation of leaves occurred under chilling temperature and strong light stress conditions. Obvious differences in the changes of the above mentioned physiological parameters between indica and japonica rice were observed. Experiments in leaves treated with inhibitors under chilling temperature and strong light conditions showed that indica rice was more sensitive to chilling temperature with strong light and subjected to photooxidation more than japonica rice. Notable positive correlation between D1 protein contents and F v/F m or (A+Z)/(A+Z+V), and a marked negative correlation between F v/F m and MDA contents were obtained by regression analysis in indica and japonica rice during chilling temperature and strong light conditions. According to the facts mentioned above, it was inferred that PSⅡ photochemical efficiency(F v/F m) was the key index to forecast for the prediction of photooxidation under stress circumstances and the physiological basis were the synthetic capacity of D1 protein and the protection of xanthophyll cycle.

Establishment of an artificial β-cell line expressing insulin under the control of doxycycline

AIM: Artificial beta-cell lines may offer an abundant source of cells for the treatment of type I diabetes, but insulin secretion in beta-cells is tightly regulated in physiological conditions. The Tet-On system is a &quot;gene switch&quot; system, which can induce gene expression by administration of tetracycline (Tet) derivatives such as doxcycline (Dox). Using this system, we established 293 cells to an artificial cell line secreting insulin in response to stimulation by Dox. METHODS: The mutated proinsulin cDNA was obtained from plasmid pcDNA3.1/C-mINS by the polymerase chain reaction (PCR), and was inserted downstream from the promoter on the expression vector pTRE2, to construct a recombined expression vector pTRE2mINS. The promoter on pTRE2 consists of the tetracycline-response element and the CMV minimal promoter and is thus activated by the reverse tetracycline-controlled transactivator (rtTA) when Dox is administrated. pTRE2mINS and plasmid pTK-Hyg encoding hygromycin were co-transfected in the tet293 cells, which express rtTA stably. Following hygromycin screening, the survived cells expressing insulin were selected and enriched. Dox was used to control the expression of insulin in these cells. At the levels of mRNA and protein, the regulating effect of Dox in culture medium on the expression of proinsulin gene was estimated respectively with Northern blot, RT-PCR, and radioimmunoassay. RESULTS: From the 28 hygromycin-resistant cell strains, we selected one cell strain (tet293/Ins6) secreting insulin not only automatically, but in response to stimulation by Dox. The amount on insulin secretion was dependent on the Dox dose (0,10,100,200,400,800 and 1000 microg.L(-1)), the level of insulin secreted by the cells treated with Dox (1000 microg.L(-1)) was 241.0pU.d(-1).cell(-1) , which was 25-fold that of 9.7pU.d(-1).cell(-1) without Dox treatment. Northern blot analyses and RT-PCR further confirmed that the transcription of insulin gene had already been up-regulated after exposing tet293/Ins6 cells to Dox for 15 minutes, and was also induced in a dose-dependent manner. However, the concentration of insulin in the media did not increase significantly until 5 hours following the addition of Dox. CONCLUSION: Human proinsulin gene was transfected successfully and expressed efficiently in 293 cells, and the expression was modulated by tetracycline and its derivatives, improving the accuracy, safety, and reliability of gene therapy, suggesting that conditional establishment of artificial beta-cells may be a useful approach to develop cellular therapy for diabetes mellitus.

Production of Benzene from Lignin through Current Enhanced Catalytic Conversion

The directional production of benzene is achieved by the current-enhanced catalytic conversion of lignin. The synergistic effect between catalyst and current promotes the depolymerization of lignin and the selective recombinant of the functional groups in the aromatic monomers. A high benzene yield of 175 gbenzene/kglignin was obtained with an excellent selectivity of 92.9 C-mol%. The process potentially provides a promising route for the production of basic petrochemical materials or high value-added chemicals using renewable biomass.

Esophageal ulceration complicating doxycycline therapy

AIM;TO report present state of iatrogenic drug-induced esophageal injury(DIEI)induced by medications in a private clinic. METHODS:Iatrogenic drug-induced esophageal injury (DIEI)induced by medications has been more frequently reported.In a private clinic we encountered 36 cases of esophageal ulcerations complicating doxycycline therapy in a mainly younger Saudi population(median age 29 years). RESULTS:The most frequent presenting symptoms were odynophagia,retrosternal burning pain and dysphagia(94 %, 75 % and 56 %,respectively).The diagnosis was according to medical history and confirmed by endoscopy in all patients. Beside withdrawal of doxycycline,when feasible,all patients were treated with a proton-pump inhibitor(PPI)and a prokinetic.Thirty patients who reported to the clinic after treatment were improved within 1-7(median 1.7)days. CONCLUSION:Esophageal ulceration has to be suspected in younger patients with odynophagia,retrosternal burning pain and/or dysphagia during the treatment with doxycycline.

X（1835）： A Possible Baryonium？

We point out that the large pp^- coupling of X（1835） and the suppression of the three-body strange final states strongly indicate that X（1835） may be a pp^- baryonium. We also point out that the branching ratio of X（1835） →ηππ should be bigger than that of X（1835） →η′ππ. We suggest BES search X（1835） in the ηππ channel Finally, X（1835） may be used a tetraquark generator if X（1835） is really established as a baryonium state.

Combined effects of light intensity and NH_4^+-enrichment on growth, pigmentation, and photosynthetic performance of Ulva prolifera(Chlorophyta)

The aim of this study was to investigate the effects of light intensity and enhanced nitrogen supply on the growth and photosynthesis of the green-tide macroalga, Ulvaprolifera. Thalli of U. prolifera were grown in natural or NH^-enriched seawater under two different light intensities for 7 days, and then the growth rate, pigmentation, and photosynthetic performance of the thalli were evaluated. The results show that the relative growth rate （RGR） was markedly higher under the high light level than under the low light level. Enrichment with NH~ enhanced the RGR under high light intensity, but did not affect RGR under low light intensity. In low light conditions, NH;-enrichment resulted in a marked decrease in the maximal photosynthetic rate （Pro） and the maximum carbon fixation rate （Vmax）, but it did not affect the half saturation constant for carbon （K0.5） or the ratio of Vmax to K0.5, which reflects the carbon acquisition efficiency. In high light conditions, Pm, K05, and the dark respiration rate （Rd） increased under NHI enrichment, but Vmax and the Vmax/Ko5 ratio decreased. Regardless of the light intensity, NH^＋4-enrichment did not affect the apparent photosynthetic efficiency （a）, which reflects the ability of the alga to use light energy at low light levels. Under both low and high light intensities, the chlorophyll a （Chl a）, chlorophyll b （Chl b）, and carotenoids （Car） contents in thalli were higher in NH1-enriched than in natural seawater, except that there was a decrease in the Chl b content of thalli in NH1-enriched seawater under low light intensity. Therefore, NH^＋4 enrichment improved the growth and photosynthetic performance of U. prolifera under high light intensity, but not under low light intensity. We discuss the possible mechanisms underlying these physiological responses.