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1.
Experiment I compared constant (CI), variable-between (VBI), and variable-within (WVI) irrelevant cues during an extradimensional (ED) shift discrimination. Performance was better for CI than for VBI and better for VBI than for VWI. Experiment II combined CI, VBI, and VWI cues with ED or intradimensional (ID) shifts. Irrelevant-cue conditions did not affect ID performance but did affect ED performance. The typical superiority of ID, as compared to ED, shifts was observed in the VWI condition but not in the CI condition. Implications for mediating-response (i.e., attention or observing-response) theories were indicated.  相似文献   

2.
以丙二酸二乙酯为原料,对2,2-二甲基-5,5-二乙氧羰基-1,3-二氧六环的合成进行了研究,产物结构经1H-NMR确定.  相似文献   

3.
目的:观察一氧化氮(NO)供体硝酸异山梨酯(Isosorbride Dinitrate,ID)及一氧化氮合酶(NOS)抑制剂氨基胍(Aminoguanidine,AG)对双侧卵巢切除(OVX)大鼠骨组织形态计量学的影响。方法:49只雌性大鼠随机分成7组,每组7只。①假手术(Sham)组、②卵巢切除(OVX)组、③卵巢切除 雌激素(OVX EB)组、④卵巢切除 NO供体(OVX ID)组、⑤卵巢切除 NO供体和雌激素(OVX ID EB)组、⑥卵巢切除 NOS抑制剂(OVX AG)组、⑦卵巢切除 NOS抑制剂和雌激素(OVX AG EB)组。实验10周后处死大鼠,对第4、5腰椎进行骨组织形态计量学分析。结果:与Sham组相比:OVX组、OVX AG组和OVX AG EB组组织形态计量学参数BV/TV和Tb.Th减少,Tb.Sp和MAR增加(P<0.05);而OVX EB组、OVX ID组和OVX ID EB组骨组织形态计量学参数BV/TV、Tb.Th、Tb.Sp和MAR均无明显差异(P>0.05)。与OVX组相比:OVX EB组、OVX ID组和OVX ID EB组骨组织形态计量学参数BV/TV和Tb.Th明显增加,Tb.Sp和MAR明显减少(P<0.05);而OVX AG组和OVX AG EB组骨组织形态计量学参数BV/TV、Tb.Th、Tb.Sp和MAR均无明显差异(P>0.05)。结论:NO供体预防OVX鼠骨丢失,NOS抑制剂则阻止雌激素预防OVX鼠骨丢失的作用。  相似文献   

4.
Separation of fluoxetine enantiomers on five chiral stationary phases (chiralcel OD-H, chiralcel OJ-H, chiralpak AD-H, cyclobond 1 2000 DM and kromasil CHI-TBB) was investigated. The optimal mobile phase compositions of fluoxetine separation on each column were hexane/isopropanol/diethyl amine (98/2/0.2, v/v/v), hexane/isopropanol/diethyl amine (99/1/0. l, v/v/v), hexane/isopropanol/diethyl amine (98/2/0.2, v/v/v), methanol/0.2% triethylamine acetic acid (TEAA) (25/75, v/v; pH 3.8) and hexane/isopropanol/diethyl amine (98/2/0.2, v/v/v), respectively. Experimental results demonstrated that baseline separation (Rs〉1.5) of fluoxetine enantiomers was obtained on chiralcel OD-H, chiralpak AD-H, and cyclobond I 2000 DM while the best separation was obtained on the last one. The eluate orders of fluoxetine enantiomers on the columns were determined. The first eluate by chiralcel OJ-H and kromasil CHI-TBB is the S-enantiomer, while by chiralpak AD-H and cyclobond 12000 DM is the R-enantiomer.  相似文献   

5.
Many Anglo‐American universities have undertaken a paradigm shift in how the dissection of human material is approached, such that students are encouraged to learn about the lives of body donors, and to respectfully “personalize” them as human beings, rather than treating the specimens as anonymous cadavers. For the purposes of this study, this provision of limited personal information regarding the life of a body donor will be referred to as “personalization” of body donors. At this time, it is unknown whether this paradigm shift in the personalization of body donors can be translated into the German‐speaking world. A shift from donor anonymity to donor personalization could strengthen students' perception of the donor as a “first patient,” and thereby reinforce their ability to empathize with their future patients. Therefore, this study aimed to collect data about the current status of donation practices at German‐speaking anatomy departments (n = 44) and to describe the opinions of anatomy departments, students (n = 366), and donors (n = 227) about possible donor personalization in medical education. Anatomy departments in Germany, Austria, and Switzerland were invited to participate in an online questionnaire. One‐tenth of registered donors at Ulm University were randomly selected and received a questionnaire (20 items, yes‐no questions) by mail. Students at the University of Ulm were also surveyed at the end of the dissection course (31 items, six‐point Likert‐scale). The majority of students were interested in receiving additional information about their donors (78.1%). A majority of donors also supported the anonymous disclosure of information about their medical history (92.5%). However, this information is only available in about 28% of the departments surveyed and is communicated to the students only irregularly. Overall, 78% of anatomy departments were not in favor of undertaking donor personalization. The results appear to reflect traditional attitudes among anatomy departments. However, since students clearly preferred receiving additional donor information, and most donors expressed a willingness to provide this information, one could argue that a change in attitudes is necessary. To do so, official recommendations for a limited, anonymous personalization of donated cadaveric specimens might be necessary. Anat Sci Educ 11: 282–293. © 2017 American Association of Anatomists.  相似文献   

6.
以二羟甲基丙酸引入亲水成分,通过预聚体分散法合成了阴离子水性聚氨酯(WPU)。对丙酮用量、加入方式,加水及加料方式,甲苯二异氰酸酯(TDI)中-NCO与聚丙二醇(PPG)中-OH摩尔量之比(R),DMPA含量及加入方式等因素对WPU制备性能的影响进行探讨。结果表明:多次加丙酮至30mL,可以缩短反应时间至5h,制备成功率达100%,且乳液性能优良;二步法实验稳定性好;在30s内分两次缓慢加水最佳;R、DMPA的量及加入方式对乳液性能有影响。  相似文献   

7.
TiO2 nanoparticles(NPs)were prepared via the hydrothermal route of TiO2 xerogel in nitric acid, hydrochloric acid and acetic acid. The physico-chemical properties of the powders were characterized by X-ray diffraction(XRD)and N2 adsorption desorption techniques. The effects of the different acids on the structure(crystal phase)and texture(primary particle size and porosity)of the TiO2 powders were explored. Results indicated that acetic acid facilitated the formation and stability of pure anatase phase. On the other hand, nitric acid and hydrochloric acid led to the transformation from anatase to rutile. The catalyst synthesized via the hydrothermal route of TiO2 xerogel in the low concentration hydrochloric acid solution(Ti-HCl-0.15)had the highest photocatalytic activity than the catalysts obtained in the other two acid solutions. The effects of the different acids were discussed in terms of acid strength, chelating effect and the thermal stability of the adsorbed acidic anions.  相似文献   

8.
The altruistic act of body donation provides a precious resource for both teaching and researching human anatomy. However, relatively little is known about individuals who donate their bodies to science (donors), and in particular whether donors in different geographical locations share similar characteristics. A multicenter prospective survey of donors registering during 2010 in three different geographical locations, New Zealand, Ireland, and the Republic of South Africa, was conducted to identify donor characteristics. The 28-question survey included sections on body donation program awareness, reasons for donating, giving tendency, education, ethnicity, relationship status, occupation, religion, and political preference. Two hundred surveys (81%) were returned [New Zealand 123 (85% response rate), Republic of South Africa 41 (67%), and Ireland 36 (92%)]. Results indicate that donors share certain characteristics including reason for donating (80% cited a desire to aid medical science as the main reason for wishing to donate their body); family structure (most donors are or have been in long-term partnerships and ≥ 85% have siblings); and a higher proportion with no religious affiliation compared to their reference population. Some variations between locations were noted including donor age, the mode of program awareness, occupation, relationship status, political preference, organ donor status and with whom donors had discussed their decision to donate. This information could be important for assisting the identification of potential body donors in new and established bequest programs.  相似文献   

9.
在有效质量近似理论下,利用变分法研究了外电场下圆柱形GaAs/Al_xGa_(1-x)As量子环中类氢施主杂质束缚能。讨论了施主杂质束缚能与量子环尺寸(径向厚度、高度)、杂质位置以及外电场间的变化规律。结果表明:随着量子环径向厚度(高度)的增大,中心施主杂质束缚能先增大后减小,显示有一极大值;施加的电场明显地改变了量子环中电子波函数的分布,导致施主杂质束缚能相应的改变;施主杂质束缚能随杂质位置的变化呈现出规律性。  相似文献   

10.
Bundles of pure carbon nanofibers were prepared by catalytic decomposition of acetylene on foam Ni. The morphological and structural characteristics of the carbon nanostructures, in the as-prepared state, were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HTEM). A special conformation of carbon nanofibers composed of segmented structures was found among the products by both SEM and TEM observations. Further HTEM examination indicated that the segments were stacked with well ordered graphite platelets arranged perpendicular to the axis of the filaments. Project supported by NSFC(Grant Nos 107202 n 19920 and 59872030)  相似文献   

11.
The copolymerization of CO and styrene catalyzed by Pd/C toward the formation of polyketones(PK)was studied in the N-valeronitrile-N'-methylimidazolium hexafluorophosphate([C4CNmim]+PF-6) medium. The synthesized PK was characterized by Fourier transform infrared(FTIR), elemental analysis, 13C-nuclear magnetic resonance(13C-NMR), differential scanning calorimetry(DSC), thermogravimetric analysis(TGA) and gel permeation chromatography(GPC). The supported ionic liquid film on the surface of Pd/C catalyst can prevent the products from covering the hole of active carbon due to its chemical stability and weak coordination ability with metal ions, and thus efficiently improve the catalytic activity. The effects of different amounts of ionic liquid on the catalytic activity and reusability of the catalyst and the molecular weight of PK were discussed. When the usage of ionic liquid is 10wt%(0.1 g ionic liquid / 1 g active carbon carrier) and the theoretical content of Pd2+ is 5wt%(0.05 g Pd2+/ 1 g active carbon carrier), the highest catalytic activity 2 963.64 gSTCO/(gPd·h) is achieved with the molecular weight and polydispersity index of PK as Mn=9 684, Mw=13 452 and Mw /Mn=1.389.  相似文献   

12.
研究目的:优化获得血红密孔菌(P.sanguineus)的最佳培养基组成,提高耐热漆酶的产量。创新要点:获得了目前文献报道的最高水平的漆酶活力。研究方法:通过单因素试验研究了不同培养基(番茄汁、麦麸、麦芽提取物和葡萄糖细菌蛋白胨培养基)和不同组合诱导剂(大豆油、阿魏酸、没食子酸、二甲基苯胺、酸性蓝62和活性蓝19分别与硫酸铜组合诱导剂)对P.sanguineus产耐热漆酶的影响。在此基础上采用中心组合试验设计,进一步研究了番茄汁培养基结合硫酸铜和大豆油组合诱导剂对P.sanguineus产耐热漆酶的影响。利用SAS10.0和响应面分析方法对试验结果进行了统计分析和建立回归模型。重要结论:通过中心组合设计优化得出P.sanguineus产耐热漆酶的最优培养基条件:以36.8%番茄汁为培养基,以3 mmol/L硫酸铜和1%大豆油作为组合诱导剂。该条件下在10 L搅拌槽生物反应器中漆酶活力达到了143 000 IU/L(2,2'-联氮双(3-乙基苯并噻唑啉-6-磺酸)为底物,pH值为3.0)。  相似文献   

13.
The Anatomical Donations Program at the University of Michigan Medical School (UMMS) has begun a multiphase project wherein interviews of donors will be recorded and later shown to medical students who participate in the anatomical dissection course. The first phase of this project included surveys of both current UMMS medical students and donors concerning their perceptions of such a program. A five‐question survey administered via Qualtrics software was electronically mailed to all current medical students at UMMS, and a survey was mailed to registered and potential donors requesting information from the UMMS on anatomical donations. A total of 224 medical student responses (response rate 33%) and 54 donor responses (response rate 27%) were received. Seventy‐four percent of students and 81% of donors reported they would participate in this program if it existed. Students and donors supported the implementation of this program for varying reasons, though many felt strongly they would not want to participate in a donor interview program. These qualitative results support those of previous studies that show a majority of students desire a closer personal relationship with the donor, and these are the first results to be reported on donor perceptions of a donor interview program. Although many students and donors are in favor of instituting this program, others feel strongly that such an experience could be traumatic. The causes of these differing reactions need to be further explored, and the opinions of those who object to this study will be respected by maintaining voluntary participation in future phases of this study. Anat Sci Educ 6: 90–100. © 2012 American Association of Anatomists.  相似文献   

14.
采用熔体快淬-去合金化法制备多孔PtFe纳米材料,通过X射线衍射、扫描电子显微镜及高分辨透射电子显微镜对其结构进行了表征.并研究了其在H2O2和3,3’,5,5’-四甲基联苯胺(TMB)催化体系中作为过氧化物酶的催化活性.研究发现,此纳米酶对H2O2和TMB具有较好的亲和性能,该催化反应符合Michaelis-Menten动力学理论.  相似文献   

15.
采用浸渍法对SBA-15分子筛进行铈改性,制备了催化剂Ce–SBA–15。X射线衍射、透射电镜和感应耦合等离子体原子发射光谱表征结果表明铈改性后的催化剂保持SBA–15高度有序的二维六方孔道结构。将该催化剂用于合成乙酸正丁酯,考察了催化剂用量,催化剂中铈含量、醇酸摩尔比及反应时间对乙酸正丁酯酯化率的影响。确定较佳操作条件:催化剂质量分数为10%,催化剂中铈的质量分数为10.74%,醇酸摩尔比为1.5∶1,反应时间为1.5 h。催化剂重复使用试验表明Ce–SBA–15具有良好的稳定性及催化活性。  相似文献   

16.
The dipping method was devised to deposit Pd onto carbon nanotube as supported catalyst(Pd/CNT) for the copolymerization of carbon monoxide(CO) and styrene(ST) towards the formation of polyketone(PK).The Pd/CNT was characterized by X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD) and high-resolution transmission electron microscopy(HRTEM).The construction and crystallization property of PK were evaluated by Fourier transform infrared spectroscopy(FTIR),13C-nuclear magnetic resonance(NMR) and XRD,respectively.The catalyst showed excellent activity and reusability in promoting the fabrication of PK.It can be recycled 14 times with the highest total catalytic activity of 4 239.64 gPK/(gPd·h) at Pd content of 8.63wt%.The results indicate that the prepared catalyst is effective to catalyze the copolymerization of CO and styrene.  相似文献   

17.
This study examined whether iron deficiency (ID) in infancy contributes to problem behaviors in adolescence through its influence on poor regulatory abilities in childhood. Chilean infants (N = 1,116) were studied when there was no national program for iron fortification (1991–1996), resulting in high rates of ID (28%) and iron‐deficiency anemia (IDA, 17%). Infants (54% male) were studied at childhood (Mage = 10 years) and adolescence (Mage = 14 years). IDA in infancy was related to excessive alcohol use and risky sexual behavior in adolescence through its effect on poor emotion regulation in childhood. Attentional control deficits at age 10 were also related to both infant IDA and heightened risk taking in adolescence. Findings elucidate how poor childhood regulatory abilities associated with infant IDA compromise adjustment in adolescence.  相似文献   

18.
A liquefied petroleum gas (LPG) sensor with high selectivity, sensitivity and low power consumption has been developed based on indium oxide with very low resistance. Nanocrystalline In203 gas sensing materials were directly synthesized through a one-step controllable solvothermal process at 210 ℃ for 24 h, using InCI3.4H2O as the starting material, cetyltrimethyl ammonium bromide (CTAB) as additive and ethanol as the solvent. The obtained samples were characterized by X-ray diffraction (XRD), and transmission electron microscopy (TEM). The results showed that indium oxide takes on uniform cubic shape with range size of 10~30 nm and fine dispersivity. Gas sensitivity was measured in a mixing static gas. The results indicated that 3.0 V is the best working voltage of the sensor to LPG. Sensitivity is 12.6. The response-time and recovery-time are 3 s and 10 s respectively. Power consumption is only around 200 mW.  相似文献   

19.
InfluenceofPoly(methylmethacrylate)DopantonButadieneDerivativeElectroluminescenceWangGuangming1(王光明)WangGuangmin2(王广民)YuanChu...  相似文献   

20.
以固体酸为催化剂,苯甲醛和醋酸酐为原料合成了1,1-二乙酸酯.此法具有操作简便,反应时间短,产率高,催化剂价廉易得,活性高,不易中毒等优点.  相似文献   

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